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The larval alimentary canal of the Antarctic insect,Belgica antarcticaJames B.Nardi a ,*,Lou Ann Miller b ,Charles Mark Bee c ,Richard E.Lee,Jr.d ,David L.Denlinger eaDepartment of Entomology,University of Illinois,320Morrill Hall,505S.Goodwin Avenue,Urbana,IL 61801,USAbCenter for Microscopy and Imaging,College of Veterinary Medicine,University of Illinois,2001S.Lincoln Avenue,Urbana,IL 61801,USA cImaging Technology Group,Beckman Institute for Advanced Science and Technology,University of Illinois,405N Mathews Avenue,Urbana,IL 61801,USA dDepartment of Zoology,Miami University,Oxford,OH 45056,USA eDepartment of Entomology,Ohio State University,400Aronoff Laboratory,318West 12th Avenue,Columbus,OH 43210,USAa r t i c l e i n f oArticle history:Received 26October 2008Accepted 17April 2009Keywords:Alimentary canal Midge AntarcticaStomodeal valve MicrovilliRegenerative cellsa b s t r a c tOn the Antarctica continent the wingless midge,Belgica antarctica (Diptera,Chironomidae)occurs further south than any other insect.The digestive tract of the larval stage of Belgica that inhabits this extreme environment and feeds in detritus of penguin rookeries has been described for the ﬁrst time.Ingested food passes through a foregut lumen and into a stomodeal valve representing an intussus-ception of the foregut into the midgut.A sharp discontinuity in microvillar length occurs at an interface separating relatively long microvilli of the stomodeal midgut region,the site where peritrophic membrane originates,from the midgut epithelium lying posterior to this stomodeal region.Although shapes of cells along the length of this non-stomodeal midgut epithelium are similar,the lengths of their microvilli increase over two orders of magnitude from anterior midgut to posterior ldings of the basal membranes also account for a greatly expanded interface between midgut cells and the hemocoel.The epithelial cells of the hindgut seem to be specialized for exchange of water with their environment,with the anterior two-thirds of the hindgut showing highly convoluted luminal membranes and the posterior third having a highly convoluted basal surface.The lumen of the middle third of the hindgut has a dense population of resident bacteria.Regenerative cells are scattered throughout the larval midgut epithelium.These presumably represent stem cells for the adult midgut,while a ring of cells,marked by a discontinuity in nuclear size at the midgut-hindgut interface,presumably represents stem cells for the adult hindgut.Ó2009Elsevier Ltd.All rights reserved.1.IntroductionDespite the dominance of insects and other terrestrial arthro-pods throughout the world,only a few species are found in Antarctica.Most are collembolans and mites,with the Class Insecta represented by only two endemic species of midges (Diptera:Chironomidae)(Convey and Block,1996).Of these,the range of the more abundant midge Belgica antarctica extends further south on the Antarctic Peninsula than that of any other insect.B.antarctica has a patchy distribution on the Peninsula,but it is particularly abundant near penguin rookeries on the small,off-shore islands near Palmer Station.In this habitat,midge larvae are subjected to a range of environmental stresses including desicca-tion,freezing,anoxia,pH ﬂuctuation from the nitrogenous run-off,and inundation from seawater as well as fresh water fromprecipitation and ice melt.Numerous physiological adaptations are apparent in the larvae:heat shock proteins are continuously up-regulated (Rinehart et al.,2006),agents to counter oxidative stress are present in abundance (Lopez-Martinez et al.,2008),loss of a high percentage of body water is tolerated and in fact contributes to enhanced freeze tolerance (Hayward et al.,2007;Elnitsky et al.,2008).Dramatic changes in metabolites (Michaud et al.,2008)and gene expression (Lopez-Martinez et al.,2009)accompany these physiological responses to environmental stress.In addition to these distinctive biochemical features of cells of B.antarctica ,it is quite possible that structural features of this insect may also deviate somewhat from the patterns observed in insects at lower latitudes.The harsh environment of Antarctica obviously places great demands on the resiliency of cells that are exposed to periodic desiccation and freezing.To promote formation of ice crystals within extracellular spaces rather than within cells,insect cells must rapidly exchange water with their extracellular environments.Expansion of luminal and/or basal surface areas of epithelial cells would facilitate this rapid exchange.*Corresponding author.Tel.:þ12173336590;fax:þ12172443499E-mail address:j-nardi@ (J.B.Nardi).Contents lists available at ScienceDirectArthropod Structure &Developmentjournal homepage :www.else /locate/asd1467-8039/$–see front matter Ó2009Elsevier Ltd.All rights reserved.doi:10.1016/j.asd.2009.04.003Arthropod Structure &Development 38(2009)377–389Special emphasis in this manuscript has been placed on the cellular architecture of the three well-delineated epithelial regionsof the insect alimentary canal–foregut,midgut,and hindgut. Secretion from the midge’s large salivary gland cells aggregates detritus particles and facilitates uptake of detritus into the gut (Oliver,1971).After passage of ingested food through the midge larva’s short and narrow foregut,digestion and absorption of ingested material occurs across the peritrophic membrane and microvilli that line the lumen of the midgut.Subsequently digested food passes into the hindgut where ions,small molecules and water are absorbed across a cuticular lining.Comparisons of internal gut morphology of arthropods complement existing studies of external morphological features and molecular characters on which traditional phylogenetic relationships,representing genetic differences among organisms, are based.Although the alimentary canals of other species in the family Chironomidae have not been examined at the cellular level of organization examined in this manuscript,a compre-hensive comparison of internal morphological characters among related species would reveal differences that presumably are based on environmental adaptations.In this study we explore the possibility that the extreme environment in which these midge larvae live shapes the architecture of their gut epithelial cells.2.Materials and methodsLarvae of B.antarctica were collected from sites near penguin rookeries on Cormorant and Humble Islands,near Palmer Station, Antarctica(64 460S,64 040W)in January and February2007.The high nitrogen run-off from penguin rookeries provides the nutrient base for the microbes,algae(Prasiola crispa),lichens and moss with which midge larvae are usually rval development is restricted to the brief austral summer,from late December until mid-February;and larvae remain immobilized in the frozen substrate for the remainder of the year.Two years are required for the larva to complete its development(Usher and Edwards,1984),and adult life is compressed into a1–2week period in late December/early January(Sugg et al.,1983).Larvae collected in Antarctica were shipped to the laboratory at Ohio State University where they were maintained with their substrate at4 C.Digestive tracts and salivary glands from32individuals were dissected withﬁne watchmaker’s forceps in Grace’s insect culture medium.Tissues were immediatelyﬁxed at4 C in a primary ﬁxative of2.5%glutaraldehyde(v/v)and0.5%paraformaldehyde (w/v)dissolved in a rinse buffer of0.1M cacodylate(pH7.4) containing0.18mM CaCl2and0.58mM sucrose.After3h in this ﬁxative,tissues were washed three times with rinse buffer before being transferred to secondaryﬁxative(2%osmium tetroxide dissolved in rinse buffer,w/v)for4h.After thoroughly washing with rinse buffer,tissues were gradually dehydrated in a graded ethanol series(10–100%,v/v).From absolute ethanol,tissues were transferred to propylene oxide and inﬁltrated with mixtures of propylene oxide and resin before being embedded in pure LX112 resin.Semithin sections for light microscopy were mounted on glass slides and stained with0.5%toluidine blue in1%borax(w/v). Ultrathin sections were mounted on grids and stained brieﬂy with saturated aqueous uranyl acetate and Luft’s lead citrate to enhance contrast.Images were taken with a Hitachi600transmission electron microscope operating at75kV.Whole mounts were prepared byﬁxing tissues at room temperature for30min in a4%solution of paraformaldehyde (w/v)dissolved in phosphate-buffered saline(PBS).After Fig.1.(a)Whole mount of larval gut with the three major divisions of the gut demarcated with arrows:fm¼foregut–midgut boundary;mh¼midgut–hindgut boundary.The stomodeal valve lies immediately posterior to fm(see Fig.4).The sclerotized head capsule is attached at the anterior end and four Malpighian tubules attach at the midgut–hindgut boundary.(b)Lateral view of the larva. Dorsal is to the right.Beneath the relatively translucent integument of the three thoracic segments(arrows point to prothoracic and metathoracic segments),lie imaginal discs for the three pairs of legs.Dorsal to these leg discs in the meso-thoracic and metathoracic segments are wing and haltere discs,respectively.Scale bar¼1.0mm.J.B.Nardi et al./Arthropod Structure&Development38(2009)377–389 378several rinses in PBS,nuclei of cells were labeled with1:1000 dilution of40,6-diamidino-2-phenylindole(DAPI,1mg/ml water)afterﬁrst permeabilizing cells for30min in a solution of 0.1%Triton X-100in PBS(v/v).Tissues were mounted under cover glasses in a solution of70%glycerin in0.1M Tris at pH 9.0(v/v).3.Results3.1.Global organization of the Belgica larval gutThe larval gut is a straight alimentary canal that is associated with a pair of salivary glands at its anterior end and four Malpighian tubules that converge with the alimentary canal at the junction of midgut and hindgut(Fig.1,mh).A prominent stomodeal valve occupies the interface between foregut and midgut(Fig.1,fm).The foregut occupies only about5%of the total length of the alimentary canal,while the endodermal midgut that occupies the region between fm and mh in Fig.1 clearly represents more than half the length of the alimentary canal.3.2.Salivary glands and foregutConspicuous salivary glands occupy the anterior end of the larval midge.These glands are both polyploid and polytene(Fig.2).Fig.3.Cuticles of foregut and epidermal epithelia have different stratiﬁcation.At higher magniﬁcation,the internal folded foregut cuticle(a)is compared with the cuticle of the external epidermis(b).A bracket extends across the foregut cuticle.The gut lumen(*)is surrounded by relatively thin cuticle compared to the thicker epidermal cuticle in(b) epithelial cells(e),pigmented fat body(f).In(c)the convoluted integument of the foregut(arrowhead)is surrounded by muscles(arrows),tracheoles(t),neural tissue(n)and salivary gland(g).Scale bars:(a)1.0m m,(b)5m m,and(c)20mm.Fig.2.Whole mount of Belgica salivary gland as viewed with Nomarski optics(a)and after labeling DNA with DAPI(b).The salivary duct is located at the arrow.Scale bar¼50m m.J.B.Nardi et al./Arthropod Structure&Development38(2009)377–389379Like glands found in other larval members of the Chironomidae,these salivary glands secrete silken threads that entrap food particles.On the foregut’s apical surface,the cuticle lining the narrow foregut lumen is about 0.3–0.5m m thick (Fig.3a).Unlike the thicker,contiguous cuticle of the larva’s exoskeleton with its inner electron-dense layer (Fig.3b),this foregut cuticle is highly convoluted and its outermost layer is electron-dense.Conspicuous muscle layers surround the foregut.The large salivary glands and larval brain in turn surround these muscles on the basal surface of the larval foregut (Fig.3c).3.3.Stomodeal valve at foregut–midgut interfaceAfter being channeled through a foregut lumen lined by a convoluted cuticle,the contents of the gut pass through a conspicuous stomodeal valve into the endoperitrophic space of the midgut epithelium.The stomodeal valve represents anintussusception of the foregut epithelium into the midgut (Figs.4a–d and 5a–c).This folding of the foregut epithelium and its cuticle creates a caecum that is lined centrally by foregut cuticle and peripherally by midgut microvilli.The interface of foregut and midgut lies at the anterior end of the caecum.At this junction of foregut and midgut,a peritrophic membrane origi-nates and lines the lumen of the more posterior midgut epithelia.3.4.Spatial differentiation of the midgut epitheliumAn abrupt epithelial discontinuity marked by disparity in midgut microvillar length occurs at the interface between the stomodeal region and the more posterior midgut epithelium (Fig.4c and 5d).Certain cells at this interface are specialized for secretion (Fig.5d–f)and possibly are endocrine cells.These cells at the posterior edge of the stomodeal valve were the only cells of the midgut observed to contain conspicuous secretorygranulesFig.4.The stomodeal valve represents an intussusception of posterior foregut epithelium (fe)into anterior midgut epithelium (me).(a)The folded foregut epithelium is surrounded by the anterior midgut.Anterior is to the right.(b,c)Longitudinal sections show inner lumen cuticle (ic)and outer lumen cuticle (oc)of the foregut.Between these two cuticles lie two foregut epithelial layers and an enteric muscle layer (m).Midgut epithelium is the outermost layer of the valve.(c)Represents the region delimited by the rectangle in (b).The morphological discontinuity is indicated by the arrow.The peritrophic membrane (p)lies in the lumen separating foregut and midgut.(d)The concentric arrangement of three epithelia,two lumina and one muscle layer is shown in this transverse section of the valve.From periphery to center:(1)midgut epithelium with microvilli lining the lumen in which the peritrophic membrane forms;(2)foregut epithelium faces this lumen and (3)enteric muscles (m)occupy the space between this foregut epithelium and the foregut epithelium facing the innermost lumen.Scale bars:(a,b,d)50m m;(c)20m m.J.B.Nardi et al./Arthropod Structure &Development 38(2009)377–389380Fig.5.At higher resolution,longitudinal sections of the stomodeal valve reveal details of peritrophic membrane formation and the presence of special secretory cells.(a)At the interface between the foregut epithelium and midgut epithelium lies a conﬂuence of muscle (m),foregut epithelium covered by cuticle (fg)and secretory microvilli (arrows)of midgut epithelium.Anterior is at the bottom.(b,c)Copious secretion of peritrophic membrane material (*)occurs from the microvilli of midgut epithelial cells at the anterior end of the stomodeal valve.Note the high density of mitochondria in the adjacent midgut cells.In (b)the newly formed peritrophic membrane (arrow)lies between the foregut (fg)cuticle and the tips of the microvilli.(d)Distinctive secretory cells (arrow)lie within the midgut epithelium of the stomodeal valve at the border between midgut cells with microvilli and midgut cells without obvious microvilli (See Fig.4c).The gut lumen is at upper left.(e,f)Close-ups of the secretory cell showing the nucleus (n),rough enoplasmic reticulum (arrowhead)and the high density of secretory granules (*).Scale bars:(a)10m m;(b,c)2m m;(d)5m m;(e)1m m;and (f)0.2m m.J.B.Nardi et al./Arthropod Structure &Development 38(2009)377–389381(Fig.5e and f).Posterior to the stomodeal valve,a striking gradient of microvillar length occurs along the antero-posterior (AP)axis of the midgut epithelium (Fig.6),with short (w 0.1to 0.2m m)microvilli occupying anterior regions of the midgut and extremely long,straight and densely packed (w 10m m,Figs.7and 9)microvilli occupying posterior regions of the midgut.This morphological gradient is evident in longitudinal sections of the midgut (Fig.6a–c)as well as the series of transverse sections from different locations along the AP axis of the Belgica gut (Figs.6d–f and 7–9).Underlying the antero-posterior topography revealed by the microvilli of the midgut is a parallel topography,at the base of the microvilli,reﬂected by contours of the apical surfaces of the midgut cells.These surfaces are most convoluted in regions of the midgut with the shortest microvilli and are least convoluted in regions of the midgut with the longest microvilli (Fig.6d–f).Rough endoplasmic reticulum (RER)is present throughout all regions of the midgut (Figs.7d,8d,and 9d).Stacks of large ﬂattened sacs of endoplasmic reticulum are especially evident in the posterior region of the midgut epithelium.Some smooth endoplasmic reticulum (SER)is interspersed among the RER of the anterior third of the midgut,with little if any SER is observed in the middle third or the posterior third of the midgut.However,clearly deﬁned Golgi complexes are not evident in any of the midgut cells.The lumen of the middle third of the Belgica midgut is lined with microvilli of intermediate length (w 1m m)that are associ-ated with electron-dense particles of uniform size (w 0.05m m).These particles lie within the ectoperitrophic space and show a strong afﬁnity for the microvilli (Fig.8a–c).Within the cyto-plasm of the underlying midgut cells,electron-dense particles of identical size are concentrated in autophagic vacuoles,each delimited by a plasma membrane,and are presumed to enter these epithelial cells by endocytosis.Numerous coated vesicles atthe base of microvilli on the luminal surfaces of these midgut cells (Fig.8c)offer an obvious route for the cellular uptake of these electron-dense particles from the ectoperitrophic space of the gut lumen.Infoldings of the basal membranes of epithelial cells are most prominent in the anterior and the posterior regions of the midgut (Figs.7c,8e,and 9c);mitochondria are most conspicuous along the basal surface of the anterior midgut (Fig.7a,c);and infoldings of the basal plasma membrane contain numerous mitochondria and electron-lucent vacuoles (Figs.7c and 9c).Regenerative cells are scattered throughout the larval midgut epithelia and presumably represent imaginal stem cells that replace the larval epithelium at metamorphosis.These cells are located basally in the larval epithelium and are densely packed with ribosomes and endoplasmic reticulum (Fig.10).3.5.Contents of the midgut lumen3.5.1.Endoperitrophic spaceWithin the gut lumen,the peritrophic membrane separates an inner endoperitrophic space from an outer ectoperitrophic space (Terra and Ferreira,1994;Fig.6).The anterior endoperitrophic space of the midgut is packed with relatively intact multicellular microbial organisms.Gradual digestion of microbes is reﬂected in the disappearance of pigmentation from the gut lumen in the posterior third of the midgut (Fig.1a).Within the conﬁnes of the midgut’s peritrophic membrane,microbial cells arranged singly or in various aggregates can be readily discerned.These cells can be identiﬁed as predominantly nonbacterial microbes –i.e.,algae,fungi,lichens,protists (Fig.11a–c).3.5.2.Ectoperitrophic spaceThe surrounding ectoperitrophic space is lined by midgut epithelium with microvilli whose lengths are graded alongtheFig.6.Longitudinal (a–c)and transverse (d–f)sections of midgut epithelium posterior to the stomodeal valve show regional differences along the antero-posterior axis of the gut.Three equally spaced regions along this axis are illustrated:(a,d)anterior region;(b,e)middle region;(c,f)posterior region.In each image the microvillar surface and gut lumen are at top.The peritrophic membrane (arrow)is visible in (a,b,d,and e).Scale bars ¼20m m.J.B.Nardi et al./Arthropod Structure &Development 38(2009)377–389382antero-posterior axis.Within one of the 10whole mounts of larval guts prepared,gregarines with distinctive appendages were found in this midgut zone (between the peritrophic matrix and midgut epithelial surface)(Fig.11d and e).Considering the isolation of these gregarines from other related host species,these protists most likely represent a distinct species of dipteran parasite.3.6.Spatial differentiation of the hindgut3.6.1.Ring of undifferentiated,presumptive adult hindgut epitheliumIn the images of the Belgica gut labeled with DAPI (Fig.12a),a discontinuity in nuclear labeling is observed at the midgut–hindgut boundary.At the anterior-most region of the larval hindgut,an imaginal ring of undifferentiated presumptive adult hindgut cells appears in whole mounts as a zone of cells with small nuclei among the polyploid nuclei in cells of the larval hindgut epithelium.Immediately posterior to the imaginal ring of epithelial cells,the anterior third of the hindgut is lined by a smooth cuticle approximately 0.25m m thick.This hindgut cuticle,like the foregut cuticle,is contiguous with the exoskeleton.Also,like the foregut cuticle,the hindgut cuticle secretes a well-delineated,electron-dense outermost cuticular layer.The arrangement of these different layers secreted by hindgut epithelial cells is distinct from the arrangement of the cuticular layers secreted by epidermal epithelia (Fig.3b).The anterior hindgut cuticle is secreted by attenuated,highly folded extensions of the apical surfaces of the hindgut epithelium containing conspicuous mitochondria and separated by large vacuoles that lack electron-density (Fig.12b andc).Fig.7.These are ultrastructural images of the anterior region of the midgut epithelium.Note the high concentration of mitochondria along the basal surface of the epithelium in (a)as well as the dark cell (arrow)at the basal surface of this epithelium.Lumen is marked with an asterisk (*).(b)The epithelial surface facing the lumen (*)is covered by short microvilli.(c)Mitochondria (arrows)are localized among membrane infoldings that lie adjacent to the basal lamina and enteric muscles (arrowhead).(d)Perinuclear region of midgut cell.Rough endoplasmic reticulum (ER)marked with arrowhead.Smooth ER marked with double arrowhead.Arrows point to mitochondria.n ¼nucleus.Scale bars:(a)5m m;(b,c)2m m;and (d)1m m.J.B.Nardi et al./Arthropod Structure &Development 38(2009)377–389383While apical ends of epithelial cells in the anterior third of the hindgut have conspicuous large vacuoles,the central region of the hindgut is occupied by epithelial cells that lack vacuoles but that have extremely convoluted apical membranes characteristic of epithelial cells involved in active transport of ions and water (Fig.12d and e).Also in the central region of the hindgut,the presence of the electron-dense bacteria observed in high-resolu-tion images is reﬂected in the pigmentation of the central portion of the hindgut as viewed in whole mounts of larval guts (Fig.1a).In the posterior third of the hindgut or rectum,the highly convoluted cuticle lining the lumen mirrors the structure of the foregut.The apical surfaces of the epithelial cells of the rectum lack infolded membranes associated with mitochondria and are apparently not specialized for transport of ions and water.The basal surface of this region,by contrast,is highly infolded.Association of this basal surface with numerous muscles suggeststhis posterior-most hindgut epithelium serves a mechanical function.In this most posterior portion of the hindgut,the lumen is devoid of both resident microbes as well as ingested microbes (Fig.12f).3.7.Muscles associated with the gut epitheliaThe basal surface of the hindgut epithelium,like the foregut epithelium,is closely apposed to a uniformly thick layer of circum-ferential muscles (w 10m m)(Figs.3c,12e,f).By contrast,muscles associated with the midgut epithelium are sparsely but regularly distributed over the midgut’s basal surface (Figs.6–9).Relatively widely dispersed muscle cells lie on the basal surface of the midgut epithelium and are embedded in the matrix of the epithelial basal lamina.These represent the longitudinal muscles of the gut.Sparsely distributed circumferential muscles are alsopresent.Fig.8.Different magniﬁcations of the middle region of the midgut are illustrated in (a–e).In images a and c,the midgut lumen is at the top;in e,it is down.Electron-dense particles occupy the space between the peritrophic membrane (arrow in a)and the microvillar parable particles are observed in autophagic vacuoles of midgut cells (arrowheads in b).(c)Higher resolution images suggest that these particles are taken up by endocytosis (arrows)at the microvillar surface.(d)Perinuclear region of midgut cell.Arrowheads indicate rough endoplasmic reticulum;arrows point to mitochondria;n ¼nucleus;me ¼membrane between two cells.(e)Basal lamina (arrowhead)and muscles (m)cover the basal surface of this ldings of the basal surface of plasma membrane are not conspicuous.Scale bars:(a)5m m;(b,c)1.0m m;(d)1m m;and (e)2m m.J.B.Nardi et al./Arthropod Structure &Development 38(2009)377–3893844.DiscussionThe study of insect diversity and evolution has been advanced by extensive surveys of molecular phylogeny and morphology of external integuments;however,knowledge and appreciation of insect diversity remain incomplete without adequate knowledge of the diversity of internal anatomy/physi-ology of insects and how this diversity is inﬂuenced by environment.With the paucity of information on the cellular architecture of insect guts,however,associating particular gut epithelial struc-tures with adaptation to particular diets and/or environments remains in a rudimentary state.Conventional descriptions of gut epithelial diversity (Lehane,1998;Noble-Nesbitt,1998;Terra et al.,1988)clearly do not consider the marked regional differ-entiation of microvilli on midgut cells of B.antarctica to be a common feature of epithelial cells of insect guts.Establishinghow general or how unique internal features are among insects,however,awaits additional structural studies on other related insect species.4.1.Differentiation of foregut–midgut boundary:structure of the peritrophic membrane and stomodeal valveA specialized luminal region at the foregut–midgut boundary can be visualized even in whole mounts of the alimentary canal (Fig.1a).In cross-sections and longitudinal sections of the alimentary canal at this boundary region,an inner concentric ring of folded foregut epithelium and associated muscle layers lies within the anterior midgut epithelium (Figs.4,5).Among the Diptera,the degree of specialization of foregut and midgut epithelial cells varies among the suborders.The most complex specialization of the foregut–midgut interface is found among the muscoid ﬂies,in which specialized anteriormidgutFig.9.In a–c,the midgut lumen is to the left.Different magniﬁcations of the posterior region of the midgut are illustrated.(a)Note numerous clear vacuoles (arrows)that lie between the luminal microvilli and the basal lamina (lower right).(b)The long microvilli are densely packed and extend approximately 10m m into the lumen.(c)The basal membranes of cells in this posterior region are highly folded.Basal lamina is indicated with arrowheads.Muscle ¼m.(d)Perinuclear region of midgut cell.Arrowheads indicate rough endoplasmic reticulum;arrows point to mitochondria.Scale bars:(a)10m m;(b)5m m;(c)2m m;and (d)1m m.J.B.Nardi et al./Arthropod Structure &Development 38(2009)377–389385epithelium is closely apposed to the stomodeal valve to form the distinctive cardia (Eisemann et al.,2001;Binnington,1988);but the simplest specialization of the foregut–midgut interface is observed in the suborder Nematocera,of which Belgica is a member.In these ﬂies,the foregut has been described as forming a short intussusception into the anterior midgut referred to as the stomodeal valve (King,1991;Wigglesworth,1930).For Belgica ,however,this intussusception of foregut as a percentage of total foregut surrounded by midgut is higher than that reported by Volf et al.(2004)for four other nem-atoceran Diptera in the families Culicidae (Culex pipiens )and Psychodidae (Lutzomyia longipalpis ,Phlebotomus duboscqi ,Phle-botomus papatasi ).Peritrophic structures for many insect species have often been described as chitinous,reticulated membranes with chitin micro-ﬁbrils in a hexagonal or orthogonal arrangement (Lehane,1998).These peritrophic structures consist of chitin networks embedded in protein–carbohydrate matrices (Wang and Granados,2001;Tellam et al.,1999).The origin and consistency of peritrophic membranes,gels and matrices differ among the insects (Terra,2001;Binnington et al.,1998).The peritrophic structures of some insects,such as lepi-dopteran larvae,have traditionally been described as arising from cells along the length of the midgut epithelium (type I peritrophic matrix).Recent studies involving labeling of lepidopteran peri-trophic proteins have indicated that while one peritrophic protein (i.e.,invertebrate intestinal mucin)is secreted by epithelial cells throughout the length of the midgut (Harper and Granados,1999),certain peritrophic proteins recognized by an antibody raised against the peritrophic membrane of Heliothis virescens are produced by specialized cells near the foregut–midgut interface (Ryerse et al.,1992).At the junction of foregut and midgut epithelia in Diptera,the peritrophic structure (type II)arises from microvilli of midgut epithelia (Eisemann et al.,2001)and lines the lumen of the more posterior midgut epithelia.In Belgica ,the midgut epithelial cells of the stomodeal valve are the only cells observed to produce a copious secretion associated with a newly formed structure that represents a type II peritrophic membrane.4.2.Regional differentiation of midgut epitheliumAt least in some insects,the midgut is differentiated both structurally and functionally along its length (Lehane,1998;Marana et al.,1997;Ferreira et al.,1990;Terra et al.,1988;Dow,1981).The marked and graded differences in microvillar lengths observed for Belgica midgut epithelial cells,however,represent an extreme example of such regional differentiation (Fig.6).Extensive infolding of the basal epithelial surface of midgut and hindgut cells,however,as frequently observed in other insects,is only evident in certain regions (anterior third and posterior third)of the Belgica midgut and the posterior third (rectum)of its hindgut (Villaro et al.,1999;Lehane,1998;Marana et al.,1997).See Figs.7c,8e,9c and 12f.The high concentrations of electron-dense particles that occupy the ectoperitrophic space of the central region of the midgut are not observed elsewhere in the alimentary canal.The presence of comparable particles in autophagic vacuoles of these midgut cells suggests that these particles are taken up by cells rather than secreted by gut cells.The high concentration of particles in the gut lumen also implies that their movement proceeds toward the low concentration of particles observed within the midgut epithelial cells.Although regenerative cells have not been observed in midgut epithelia of certain immature arthropods such aslarvalFig.10.Regenerative cells (asterisks)of midgut epithelium are scattered throughout the larval epithelium.Cells from different regions along the antero-posterior axis are shown.(a)Anterior third.(b)Middle third.(c)Posterior third.Arrowheads point to basal laminae;m ¼muscles;n ¼nuclei of regenerative cells.Scale bars ¼2.0m m.J.B.Nardi et al./Arthropod Structure &Development 38(2009)377–389386。

最全ASCII码对照表

最全ASCII码对照表Bin Dec Hex 缩写/字符解释0000 0000 0 00 NUL (null) 空字符0000 0001 1 01 SOH (start of handing) 标题开始0000 0010 2 02 STX (start of text) 正文开始0000 0011 3 03 ETX (end of text) 正文结束0000 0100 4 04 EOT (end of transmission) 传输结束0000 0101 5 05 ENQ (enquiry) 请求0000 0110 6 06 ACK (acknowledge) 收到通知0000 0111 7 07 BEL (bell) 响铃0000 1000 8 08 BS (backspace) 退格0000 1001 9 09 HT (horizontal tab) 水平制表符0000 1010 10 0A LF (NL line feed, new line) 换行键0000 1011 11 0B VT (vertical tab) 垂直制表符0000 1100 12 0C FF (NP form feed, new page) 换页键0000 1101 13 0D CR (carriage return) 回车键0000 1110 14 0E SO (shift out) 不用切换0000 1111 15 0F SI (shift in) 启用切换0001 0000 16 10 DLE (data link escape) 数据链路转义0001 0001 17 11 DC1 (device control 1) 设备控制1 0001 0010 18 12 DC2 (device control 2) 设备控制2 0001 0011 19 13 DC3 (device control 3) 设备控制3 0001 0100 20 14 DC4 (device control 4) 设备控制4 0001 0101 21 15 NAK (negative acknowledge) 拒绝接收0001 0110 22 16 SYN (synchronous idle) 同步空闲0001 0111 23 17 ETB (end of trans. block) 传输块结束0001 1000 24 18 CAN (cancel) 取消0001 1001 25 19 EM (end of medium) 介质中断0001 1010 26 1A SUB (substitute) 替补0001 1011 27 1B ESC (escape) 溢出0001 1100 28 1C FS (file separator) 文件分割符0001 1101 29 1D GS (group separator) 分组符0001 1110 30 1E RS (record separator) 记录分离符0001 1111 31 1F US (unit separator) 单元分隔符0010 0000 32 20 空格0010 0001 33 21 !0010 0010 34 22 "0010 0011 35 23 #0010 0100 36 24 $0010 0110 38 26 & 0010 0111 39 27 ' 0010 1000 40 28 ( 0010 1001 41 29 ) 0010 1010 42 2A * 0010 1011 43 2B + 0010 1100 44 2C , 0010 1101 45 2D - 0010 1110 46 2E . 0010 1111 47 2F / 0011 0000 48 30 0 0011 0001 49 31 1 0011 0010 50 32 2 0011 0011 51 33 3 0011 0100 52 34 4 0011 0101 53 35 5 0011 0110 54 36 6 0011 0111 55 37 7 0011 1000 56 38 8 0011 1001 57 39 9 0011 1010 58 3A : 0011 1011 59 3B ; 0011 1100 60 3C < 0011 1101 61 3D = 0011 1110 62 3E > 0011 1111 63 3F ? 0100 0000 64 40 @ 0100 0001 65 41 A 0100 0010 66 42 B 0100 0011 67 43 C 0100 0100 68 44 D 0100 0101 69 45 E 0100 0110 70 46 F 0100 0111 71 47 G 0100 1000 72 48 H 0100 1001 73 49 I 0100 1010 74 4A J 0100 1011 75 4B K 0100 1100 76 4C L 0100 1101 77 4D M 0100 1110 78 4E N 0100 1111 79 4F O 0101 0000 80 50 P0101 0010 82 52 R 0101 0011 83 53 S 0101 0100 84 54 T 0101 0101 85 55 U 0101 0110 86 56 V 0101 0111 87 57 W 0101 1000 88 58 X 0101 1001 89 59 Y 0101 1010 90 5A Z 0101 1011 91 5B [ 0101 1100 92 5C \ 0101 1101 93 5D ] 0101 1110 94 5E ^ 0101 1111 95 5F _ 0110 0000 96 60 ` 0110 0001 97 61 a 0110 0010 98 62 b 0110 0011 99 63 c 0110 0100 100 64 d 0110 0101 101 65 e 0110 0110 102 66 f 0110 0111 103 67 g 0110 1000 104 68 h 0110 1001 105 69 i 0110 1010 106 6A j 0110 1011 107 6B k 0110 1100 108 6C l 0110 1101 109 6D m 0110 1110 110 6E n 0110 1111 111 6F o 0111 0000 112 70 p 0111 0001 113 71 q 0111 0010 114 72 r 0111 0011 115 73 s 0111 0100 116 74 t 0111 0101 117 75 u 0111 0110 118 76 v 0111 0111 119 77 w 0111 1000 120 78 x 0111 1001 121 79 y 0111 1010 122 7A z 0111 1011 123 7B { 0111 1100 124 7C |0111 1110 126 7E ~0111 1111 127 7F DEL (delete) 删除ESC键VK_ESCAPE (27)回车键：VK_RETURN (13)TAB键：VK_TAB (9)Caps Lock键：VK_CAPITAL (20)Shift键：VK_SHIFT ()Ctrl键：VK_CONTROL (17)Alt键：VK_MENU (18)空格键：VK_SPACE (/32)退格键：VK_BACK (8)左徽标键：VK_LWIN (91)右徽标键：VK_LWIN (92)鼠标右键快捷键：VK_APPS (93)Insert键：VK_INSERT (45)Home键：VK_HOME (36)Page Up：VK_PRIOR (33)PageDown：VK_NEXT (34)End键：VK_END (35)Delete键：VK_DELETE (46)方向键(←)：VK_LEFT (37)方向键(↑)：VK_UP (38)方向键(→)：VK_RIGHT (39)方向键(↓)：VK_DOWN (40)F1键：VK_F1 (112)F2键：VK_F2 (113)F3键：VK_F3 (114)F4键：VK_F4 (115)F5键：VK_F5 (116)F6键：VK_F6 (117)F7键：VK_F7 (118)F8键：VK_F8 (119)F9键：VK_F9 (120)F10键：VK_F10 (121)F11键：VK_F11 (122)F12键：VK_F12 (123)Num Lock键：VK_NUMLOCK (144)小键盘0：VK_NUMPAD0 (96)小键盘1：VK_NUMPAD0 (97)小键盘2：VK_NUMPAD0 (98)小键盘3：VK_NUMPAD0 (99)小键盘4：VK_NUMPAD0 (100)小键盘5：VK_NUMPAD0 (101)小键盘6：VK_NUMPAD0 (102)小键盘7：VK_NUMPAD0 (103)小键盘8：VK_NUMPAD0 (104)小键盘9：VK_NUMPAD0 (105)小键盘.：VK_DECIMAL (110)小键盘*：VK_MULTIPLY (106)小键盘+：VK_MULTIPLY (107)小键盘-：VK_SUBTRACT (109)小键盘/：VK_DIVIDE (111)Pause Break键：VK_PAUSE (19)Scroll Lock键：VK_SCROLL (145)关键字：最全ASCII码对照表ASCII码值对照表ASCII码值ASCII码中英文对照表。

最全ASCII码对照表

最全ASCII码对照表2009-04-15 00:00Bin Dec Hex 缩写/字符解释0000 0000 0 00 NUL (null) 空字符0000 0001 1 01 SOH (start of handing) 标题开始0000 0010 2 02 STX (start of text) 正文开始0000 0011 3 03 ETX (end of text) 正文结束0000 0100 4 04 EOT (end of transmission) 传输结束0000 0101 5 05 ENQ (enquiry) 请求0000 0110 6 06 ACK (acknowledge) 收到通知0000 0111 7 07 BEL (bell) 响铃0000 1000 8 08 BS (backspace) 退格0000 1001 9 09 HT (horizontal tab) 水平制表符0000 1010 10 0A LF (NL line feed, new line) 换行键0000 1011 11 0B VT (vertical tab) 垂直制表符0000 1100 12 0C FF (NP form feed, new page) 换页键0000 1101 13 0D CR (carriage return) 回车键0000 1110 14 0E SO (shift out) 不用切换0000 1111 15 0F SI (shift in) 启用切换0001 0000 16 10 DLE (data link escape) 数据链路转义0001 0001 17 11 DC1 (device control 1) 设备控制1 0001 0010 18 12 DC2 (device control 2) 设备控制2 0001 0011 19 13 DC3 (device control 3) 设备控制3 0001 0100 20 14 DC4 (device control 4) 设备控制4 0001 0101 21 15 NAK (negative acknowledge) 拒绝接收0001 0110 22 16 SYN (synchronous idle) 同步空闲0001 0111 23 17 ETB (end of trans. block) 传输块结束0001 1000 24 18 CAN (cancel) 取消0001 1001 25 19 EM (end of medium) 介质中断0001 1010 26 1A SUB (substitute) 替补0001 1011 27 1B ESC (escape) 溢出0001 1100 28 1C FS (file separator) 文件分割符0001 1101 29 1D GS (group separator) 分组符0001 1110 30 1E RS (record separator) 记录分离符0001 1111 31 1F US (unit separator) 单元分隔符0010 0000 32 20 空格0010 0001 33 21 !0010 0010 34 22 "0010 0011 35 23 #0010 0100 36 24 $0010 0101 37 25 %0010 0110 38 26 &0010 0111 39 27 '0010 1000 40 28 (0010 1001 41 29 )0010 1101 45 2D - 0010 1110 46 2E . 0010 1111 47 2F / 0011 0000 48 30 0 0011 0001 49 31 1 0011 0010 50 32 2 0011 0011 51 33 3 0011 0100 52 34 4 0011 0101 53 35 5 0011 0110 54 36 6 0011 0111 55 37 7 0011 1000 56 38 8 0011 1001 57 39 9 0011 1010 58 3A : 0011 1011 59 3B ; 0011 1100 60 3C < 0011 1101 61 3D = 0011 1110 62 3E > 0011 1111 63 3F ? 0100 0000 64 40 @ 0100 0001 65 41 A 0100 0010 66 42 B 0100 0011 67 43 C 0100 0100 68 44 D 0100 0101 69 45 E 0100 0110 70 46 F 0100 0111 71 47 G 0100 1000 72 48 H 0100 1001 73 49 I 0100 1010 74 4A J 0100 1011 75 4B K 0100 1100 76 4C L 0100 1101 77 4D M 0100 1110 78 4E N 0100 1111 79 4F O 0101 0000 80 50 P 0101 0001 81 51 Q 0101 0010 82 52 R 0101 0011 83 53 S 0101 0100 84 54 T 0101 0101 85 55 U 0101 0110 86 56 V 0101 0111 87 57 W 0101 1000 88 58 X0101 1100 92 5C \0101 1101 93 5D ]0101 1110 94 5E ^0101 1111 95 5F _0110 0000 96 60 `0110 0001 97 61 a0110 0010 98 62 b0110 0011 99 63 c0110 0100 100 64 d0110 0101 101 65 e0110 0110 102 66 f0110 0111 103 67 g0110 1000 104 68 h0110 1001 105 69 i0110 1010 106 6A j0110 1011 107 6B k0110 1100 108 6C l0110 1101 109 6D m0110 1110 110 6E n0110 1111 111 6F o0111 0000 112 70 p0111 0001 113 71 q0111 0010 114 72 r0111 0011 115 73 s0111 0100 116 74 t0111 0101 117 75 u0111 0110 118 76 v0111 0111 119 77 w0111 1000 120 78 x0111 1001 121 79 y0111 1010 122 7A z0111 1011 123 7B {0111 1100 124 7C |0111 1101 125 7D }0111 1110 126 7E ~0111 1111 127 7F DEL (delete) 删除ESC键VK_ESCAPE (27)回车键：VK_RETURN (13)TAB键：VK_TAB (9)Caps Lock键：VK_CAPITAL (20)Shift键：VK_SHIFT ()Ctrl键：VK_CONTROL (17)Alt键：VK_MENU (18)空格键：VK_SPACE (/32)退格键：VK_BACK (8)左徽标键：VK_LWIN (91)右徽标键：VK_LWIN (92)鼠标右键快捷键：VK_APPS (93) Insert键：VK_INSERT (45) Home键：VK_HOME (36) Page Up：VK_PRIOR (33) PageDown：VK_NEXT (34)End键：VK_END (35)Delete键：VK_DELETE (46)方向键(←)：VK_LEFT (37)方向键(↑)：VK_UP (38)方向键(→)：VK_RIGHT (39)方向键(↓)：VK_DOWN (40)F1键：VK_F1 (112)F2键：VK_F2 (113)F3键：VK_F3 (114)F4键：VK_F4 (115)F5键：VK_F5 (116)F6键：VK_F6 (117)F7键：VK_F7 (118)F8键：VK_F8 (119)F9键：VK_F9 (120)F10键：VK_F10 (121)F11键：VK_F11 (122)F12键：VK_F12 (123)Num Lock键：VK_NUMLOCK (144) 小键盘0：VK_NUMPAD0 (96) 小键盘1：VK_NUMPAD0 (97) 小键盘2：VK_NUMPAD0 (98) 小键盘3：VK_NUMPAD0 (99) 小键盘4：VK_NUMPAD0 (100) 小键盘5：VK_NUMPAD0 (101) 小键盘6：VK_NUMPAD0 (102) 小键盘7：VK_NUMPAD0 (103) 小键盘8：VK_NUMPAD0 (104) 小键盘9：VK_NUMPAD0 (105) 小键盘.：VK_DECIMAL (110) 小键盘*：VK_MULTIPLY (106) 小键盘+：VK_MULTIPLY (107) 小键盘-：VK_SUBTRACT (109) 小键盘/：VK_DIVIDE (111) Pause Break键：VK_PAUSE (19) Scroll Lock键：VK_SCROLL (145)。

ASCII码表二进制十进制十六进制

ASCII码表（二进制十进制十六进制）控制字符二进制十进制十六进制缩写解释0000 0000 0 0 NUL 空字符(Null)0000 0001 1 1 SOH 标题开始0000 0010 2 2 STX 正文开始0000 0011 3 3 ETX 正文结束0000 0100 4 4 EOT 传输结束0000 0101 5 5 ENQ 请求0000 0110 6 6 ACK 收到通知0000 0111 7 7 BEL 响铃0000 1000 8 8 BS 退格0000 1001 9 9 HT 水平制表符0000 1010 10 0A LF 换行键0000 1011 11 0B VT 垂直制表符0000 1100 12 0C FF 换页键0000 1101 13 0D CR 回车键0000 1110 14 0E SO 不用切换0000 1111 15 0F SI 启用切换0001 0000 16 10 DLE 数据链路转义0001 0001 17 11 DC1 设备控制10001 0010 18 12 DC2 设备控制20001 0011 19 13 DC3 设备控制30001 0100 20 14 DC4 设备控制40001 0101 21 15 NAK 拒绝接收0001 0110 22 16 SYN 同步空闲0001 0111 23 17 ETB 传输块结束0001 1000 24 18 CAN 取消0001 1001 25 19 EM 介质中断0001 1010 26 1A SUB 替补0001 1011 27 1B ESC 溢出0001 1100 28 1C FS 文件分割符0001 1101 29 1D GS 分组符0001 1110 30 1E RS 记录分离符0001 1111 31 1F US 单元分隔符0111 1111 127 7F DEL 删除可显示字符二进制十进制十六进制字符0010 0000 32 20 空格0010 0001 33 21 !0010 0010 34 22 "0010 0011 35 23 #0010 0100 36 24 $0010 0101 37 25 %0010 0110 38 26 &0010 0111 39 27 '0010 1000 40 28 (0010 1001 41 29 )0010 1010 42 2A *0010 1011 43 2B +0010 1100 44 2C ,0010 1101 45 2D -0010 1110 46 2E .0010 1111 47 2F /0011 0000 48 30 00011 0001 49 31 10011 0010 50 32 20011 0011 51 33 30011 0100 52 34 40011 0101 53 35 50011 0110 54 36 60011 0111 55 37 70011 1000 56 38 80011 1001 57 39 90011 1010 58 3A :0011 1011 59 3B ;0011 1100 60 3C <0011 1101 61 3D =0011 1110 62 3E >0011 1111 63 3F ?可显示字符二进制十进制十六进制字符0100 0001 65 41 A0100 0010 66 42 B0100 0011 67 43 C0100 0100 68 44 D0100 0101 69 45 E0100 0110 70 46 F0100 0111 71 47 G0100 1000 72 48 H0100 1001 73 49 I0100 1010 74 4A J0100 1011 75 4B K0100 1100 76 4C L0100 1101 77 4D M0100 1110 78 4E N0100 1111 79 4F O0101 0000 80 50 P0101 0001 81 51 Q0101 0010 82 52 R0101 0011 83 53 S0101 0100 84 54 T0101 0101 85 55 U0101 0110 86 56 V0101 0111 87 57 W0101 1000 88 58 X0101 1001 89 59 Y0101 1010 90 5A Z0101 1011 91 5B [0101 1100 92 5C \0101 1101 93 5D ]0101 1110 94 5E ^0101 1111 95 5F _0110 0000 96 60 `可显示字符二进制十进制十六进制字符0110 0001 97 61 a0110 0011 99 63 c 0110 0100 100 64 d 0110 0101 101 65 e 0110 0110 102 66 f 0110 0111 103 67 g 0110 1000 104 68 h 0110 1001 105 69 i 0110 1010 106 6A j 0110 1011 107 6B k 0110 1100 108 6C l 0110 1101 109 6D m 0110 1110 110 6E n 0110 1111 111 6F o 0111 0000 112 70 p 0111 0001 113 71 q 0111 0010 114 72 r 0111 0011 115 73 s 0111 0100 116 74 t 0111 0101 117 75 u 0111 0110 118 76 v 0111 0111 119 77 w 0111 1000 120 78 x 0111 1001 121 79 y 0111 1010 122 7A z 0111 1011 123 7B { 0111 1100 124 7C | 0111 1101 125 7D } 0111 1110 126 7E ~。

1-s2.0-S0146638012000599-main

A ﬁrst step towards identiﬁcation of tannin-derived black carbon:Conventional pyrolysis (Py–GC–MS)and thermally assisted hydrolysis and methylation (THM–GC–MS)of charred condensed tanninsJoeri Kaal a ,⇑,Klaas G.J.Nierop b ,Peter Kraal c ,Caroline M.Preston daInstituto de Ciencias del Patrimonio (Incipit),Consejo Superior de Investigaciones Cientíﬁcas (CSIC),San Roque 2,15704Santiago de Compostela,Spain bDepartment of Earth Sciences –Organic Geochemistry,Faculty of Geosciences,Utrecht University,P.O.Box 80021,3508TA Utrecht,The Netherlands cSouthern Cross GeoScience,Southern Cross University,P.O.Box 157,Lismore,2480New South Wales,Australia dPaciﬁc Forestry Centre,Natural Resources Canada,506West Burnside Rd.,Victoria,BC,Canada V8Z 1M5a r t i c l e i n f o Article history:Received 5October 2011Received in revised form 13March 2012Accepted 26March 2012Available online 5April 2012a b s t r a c tTannins account for a signiﬁcant proportion of plant biomass and are likely to contribute to the residues formed by incomplete biomass combustion (black carbon,BC).Nonetheless,the molecular properties of thermally modiﬁed tannins have not been investigated in laboratory charring experiments.We applied conventional analytical pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS)and thermally assisted hydrolysis and methylation (THM–GC–MS)to investigate the effects of heat treatment with a mufﬂe furnace on the properties of condensed tannins (CT)from Corsican pine (Pinus nigra )needles.Py–GC–MS showed a decrease in the relative abundance of the 1,2,3-trihydroxybenzenes (pyrogallols)at P 300°C and of the dihydroxybenzenes (mainly catechols)at P 350°C due to dehydroxylation of the CT B ring.Further dehydroxylation led to formation of monohydroxybenzenes (phenols),which showed a strong enrichment between 350and 400°C and,at higher temperatures,to a series of mono-cyclic and polycyclic aromatics [benzene,alkyl benzenes and polycondensed aromatic hydrocarbons (PAHs)].Degradation of the A ring could not be recognized via Py–GC–MS,probably because of the poor chromatographic behavior of 1,3,5-trihydroxybenzenes (phloroglucinols).The progressive dehydroxyla-tion and eventual polycondensation of the CT B ring was corroborated using THM–GC–MS.In addition,with THM–GC–MS the thermal rearrangement of CT A rings at 300°C and higher was inferred from the relative abundance of 1,3,5-trimethoxybenzenes (methylated phloroglucinol derivatives).These com-pounds were observed at moderate/high temperature (up to 450°C)and can not be produced from THM of lignin,suggesting that they may be markers of CT in natural BC samples.Ó2012Elsevier Ltd.All rights reserved.1.IntroductionTannins are among the most abundant plant biopolymers,typ-ically comprising 10–25%of foliar mass (Kraus et al.,2003).In leaves,needles and bark,tannin content often exceeds that of lig-nin (Hernes and Hedges,2004)and it is also present in woody tis-sue (Rogge et al.,1998).Tannins are strong antioxidants with multiple ecosystem functions,such as defense against herbivores,metal mobilization,radical scavenging and regulation of nutrient dynamics by protein precipitation and suppression of microbial activity (Zucker,1983;Kennedy et al.,1996;Fierer et al.,2001).Tannins from terrestrial plants can be divided into two main groups:condensed tannins (CT)and hydrolyzable tannins.Con-densed tannins are oligomers and polymers based on ﬂavan-3-ol monomers linked through covalent bonds (Fig.1).Within thegroup of CT,there is variation in the distribution of OH groups on the aromatic B ring,forming procyanidin and prodelphinidin CT (e.g.Khanbabaee and van Ree,2001).Each CT monomer con-tains up to six OH functionalities concentrated on the aromatic A and B rings (Fig.1).These aromatic OH groups,especially those in adjacent positions on the B ring,give rise to the exceptional reactivity of CT in the environment (Slabbert,1992).Despite the fact that tannins form a major component of plant biomass,they have often been ignored as a possible source of poly-phenolic substances in soil organic matter;these have commonly been ascribed to lignin (Filley et al.,2006).This is also the case for phenolic moieties in biomass burning residue (black carbon,BC)(Baldock and Smernik,2002;Krull et al.,2003),which are abundant in BC formed at low/moderate temperature (e.g.Knicker et al.,2005,2007;Rumpel et al.,2006).In the light of growing interest in BC or ‘biochar’,amendment programs for soil ameliora-tion and C sequestration (Lehmann et al.,2006;Jeffery et al.,2011),the possible effects of charred tannins on soil microbial and nutri-ent dynamics must be understood (Warnock et al.,2010),as they0146-6380/$-see front matter Ó2012Elsevier Ltd.All rights reserved./10.1016/geochem.2012.03.009Corresponding author.Tel.:+34881813588;fax:+34881813601.E-mail address:joeri.kaal@incipit.csic.es (J.Kaal).may be anticipated to be vastly different from that of charred lig-nin.This is not possible,however,as methodologies for identifying charred tannins are not available and the thermal degradation pathways of tannins are largely unknown.The thermal alteration of plant tissue has been investigated in numerous studies,as reviewed by e.g.González-Pérez et al.(2004)and Preston and Schmidt (2006).Pyrolysis–gas chromatog-raphy–mass spectrometry (Py–GC–MS)is one method that can provide information on the molecular properties of BC (De la Rosa et al.,2008;Kaal and Rumpel,2009;Kaal et al.,2009;Fabbri et al.,2012),despite the fact that pyrolysis itself is a heat-induced scission reaction and that secondary rearrangements generate structures that may resemble the pyrolysis products of BC (Saiz-Jiménez,1994;Wampler,1999).Pyrolysis is a relatively inex-pensive and rapid technique that has also proven of value for tan-nin characterization (Galletti et al.,1995).Flash heating in the presence of tetramethylammonium hydroxide (TMAH)is referred to as thermally assisted hydrolysis and methylation (THM)or ther-mochemolysis.With THM,hydrolyzable bonds are cleaved and the resulting CO 2H and OH groups are transformed in situ to the corre-sponding methyl esters and methyl ethers,respectively (Challinor,2001;Hatcher et al.,2001;Shadkami and Helleur,2010),which are more amenable to GC than their underivatized counterparts.As such,THM–GC–MS provides additional information on tannin structure through detection of derivatized polyfunctionalized A and B rings (Nierop et al.,2005).In the present study the thermal degradation of CT was studied using laboratory charring experiments followed by characteriza-tion with Py–GC–MS and THM–GC–MS.The aim was to provide guidelines for the identiﬁcation of CT-derived BC and identify the molecular changes as a function of charring temperature.2.Material and methodsCondensed tannins were isolated from Corsican pine (Pinus ni-gra var.maritima )needles from the coastal dunes in The Nether-lands (52°2004500N,4°3105700E)using the scheme proposed by Preston (1999)and described in detail by Nierop et al.(2005,2006).The CT were completely isolated from other components and had a prodelphinidin:procyanidin ratio of 2:1and average chain length of 6.6(Nierop et al.,2005).It has been used in various studies (Kaal et al.,2005;Nierop et al.,2006;Kraal et al.,2009).For the charring experiments,ca.200mg of CT were double wrapped in Al foil to simulate limited O 2availability during wild-ﬁres.The samples were placed (30min)in a preheated mufﬂe fur-nace at temperatures (T CHAR )from 200°C to 600°C.Similar experiments have been performed by Turney et al.(2006),Hall et al.(2008)and Wiesenberg et al.(2009).Weight loss was deter-mined gravimetrically before and after charring.C and H contents were determined by way of combustion using a LECO carbon ana-lyzer (model CHN-1000).Uncharred CT was used as a control.Py–GC–MS was performed in duplicate using a Pt ﬁlament coil probe Pyroprobe 5000pyrolyzer (CDS Analytical,Oxford,USA).Approximately 1–1.5mg sample was embedded in quartz tubes using glass wool.Pyrolysis was applied at 750°C for 10s (heating rate 10°C/ms).The method produces limited artiﬁcial charring during pyrolysis and a relatively high proportion of pyrolyzable biomass in comparison with pyrolysis at lower temperatures (Pastorova et al.,1994;Kaal et al.,2009;Song and Peng,2010).The pyrolysis interface was coupled to a 6890N GC instrument and 5975MSD (Agilent Technologies,Palo Alto,USA).The pyrolysis interface and GC inlet (split ratio 1:20)were set at 325°C.The GC instrument was equipped with a (non-polar)HP-5MS 5%phenyl,95%dimethylpolysiloxane column (30m Â0.25mm i.d.;ﬁlm thickness 0.25l m)and He was the carrier gas (constant ﬂow 1ml/min).The GC oven was heated from 50to 325°C (held 10min)at 20°C/min.The GC–MS transfer line was held at 270°C,the ion source (electron impact mode,70eV)at 230°C and the quadrupole detector at 150°C scanning a range between m /z 50and 500.Peak areas of the pyrolysis products were obtained from one or two characteristic or dominant fragment ions,the sum of which (total quantiﬁed peak area;TQPA)was set as 100%.Relative contributions of the pyrolysis products were calculated as %of TQPA.This is a semi-quantitative exercise that allows better comparison between samples than visual inspection of pyrolysis chromatograms alone.Benzofuran and styrene could not be quantiﬁed because of co-elution with contaminants.For THM–GC–MS,samples were pressed onto Curie-Point wires,after which a droplet of a 25%solution of TMAH in water was added,prior to drying under a 100W halogen lamp.THM was car-ried out using a Horizon Instruments Curie-Point pyrolyzer.Sam-ples were heated for 5s at 600°C.The pyrolysis unit was connected to a Carlo Erba GC8060furnished with a fused silica col-umn (Varian,25m Â0.25mm i.d.)coated with CP-Sil 5(ﬁlm thick-ness 0.40l m).He was the carrier gas.The oven temperature program was:40°C (1min)to 200°C at 7°C/min and then to 320°C (held 5min)at 20°C/min.The column was coupled to a Fi-sons MD800MS instrument (m /z 45–650,ionization energy 70eV,cycle time 0.7s).Like Py–GC–MS,the relative contributions of the THM products were calculated as relative contributions to TQPA using 1–2dominant fragment ions.Benzene and toluene were not detected because they co-eluted with trimethylamine,the main side product of TMAH-based THM (Challinor,2001),i.e.with-in the solvent delay period (3min).Py–GC–MS and THM–GC–MS results were analyzed via princi-pal component analysis (PCA)to illustrate the major effects of heating on the pyrolysis and THM ﬁngerprints,respectively,using SPSS 13.0.3.Results and discussion3.1.Weight loss and elemental compositionWeight loss from CT increased from 17%at T CHAR 200°C towards 56%at T CHAR 600°C (Table 1).The CT C content increased from 51%to 81%with increasing T CHAR .The atomic H/C ratio of the samples declined from 1.2to 0.6with increasing T CHAR ,reﬂecting loss of functional groups and formation of fused aromatic clusters through condensation (Braadbaart et al.,2004).Model structure of a condensed tannin oligomer;procyanidin,prodelphinidin,R =OH.47(2012)99–108chromatograms of uncharred(control)and charred(200–600°C)CT,from Py–GC–MS.Relative peak intensity vs.retention time3.2.Charred condensed tannin composition:Py–GC–MSPy–GC–MS total ion chromatograms are depicted in Fig.2.Total quantiﬁed peak area (Table 1),a rough measure of signal intensity,decreased with increasing T CHAR .This can be explained by the for-mation of non-pyrolyzable structures upon charring,probably through the formation of polycondensed aromatic clusters stable under pyrolysis conditions.However,this does not imply that the results from the high temperature chars should be dismissed for representing only a small and relatively volatilefraction:a more appropriate interpretation is that the samples consist largely of non-pyrolyzable fused aromatic clusters,corroborated by the dom-inant pyrolysis products of such samples (benzene and PAHs;see below)and lack of pyrolysis products from less intensely charred structures.The major pyrolysis products are listed in sponding retention times,fragment ions used and relative proportions.Products were structure,in particular the hydroxylation between benzenes (benzene and alkyl (with one OH),dihydroxybenzenes (DHB),(THB)and other compounds.The DHB are while the THB are based on pyrogallol moieties exclusively from prodelphinidin B rings.The uncharred CT isolate produced mainly pyrolysis (Table 2;Fig.3),which originate from prodelphinidin B rings,respectively.In contrast delphinidin:procyanidin ratio determined et al.,2005),the DHB were more abundant may be explained by way of the poor ‘‘visibility’’a non-polar GC column.The high proportion of and 4-methylpyrogallol points to scission of the the heterocyclic pyran C ring (Fig.1),which has sociation energy than the aromatic A and B acetone and acetic acid may represent the after pyrolysis.Products from the A ring were may be explained by the poor chromatographic rivatized 1,3,5-trihydroxybenzene principal pyrolysis product from the A ring (The lack of unambiguous A ring markers implies that Py–GC–MS cannot be used to study the degradation of the predominantly C-4/C-8and C-4/C-6intermonomeric linkages (Fig.1),and thus to investigate CT depolymerization.Some methoxyphenols (guaiacol and 4-vinylguaiacol)and catechol carbonate were detected.The guaiacols are commonly attributed to lignin and its derivatives (e.g.Kögel-Knabner,2002),but here they might alternatively orig-inate from C ring ﬁssion in CT (Galletti et al.,1995).The possibility of tannins as a source of the guaiacols is supported by the absence of resonances from methoxyphenols in liquid-state 13C NMR tra (Nierop et al.,2005)and guaiacols bearing a C 3side chain pyrolyzate,which should be detectable if residual lignin was ent in the fresh needle isolate (Saiz-Jiménez and de Leeuw,The results for uncharred CT were in good agreement with earlier pyrolysis experiments with tannin,catechin and gallocate-Relative proportion (TQPA)of pyrolysis product groups from CT vs.charring temperature (200–600°C);0°C,control (uncharred CT);THB,trihydroxybenzene;dihydroxybenzene;PAH,polycyclic aromatic hydrocarbon.Error bars reﬂect standard error of mean of two replicates.Note differences in y -axis scaling.Pyrolysis products plotted in PC1–PC2space (PCA).THB,trihydroxybenzene;dihydroxybenzene;PAH,polycyclic aromatic hydrocarbon.Arrow indicates trend in pyrolysis patterns with increasing charring temperature.The sample charred at200°C gave a pyrogram similar to that of uncharred CT,indicating limited thermal rearrangement at this temperature(Fig.2).At T CHAR300°C,the proportion of THB de-creased from ca.20%to ca.5%of the TQPA,while the proportion of DHB increased towards ca.70%(Fig.3).This reﬂects elimination of one OH from the prodelphinidin B ring during charring,causing a relative increase in the contribution of DHB to the pyrolyzate. Thus,the presence of DHB in pyrolyzates does not necessarily indi-cate the presence of uncharred CT.This sheds new light on results from previous studies(Quénéa et al.,2005a,b)in which the pres-ence of DHB in the pyrolyzate of BC-containing forest soil was interpreted as being from uncharred CT,whereas it may alterna-tively originate from CT-derived BC.A more drastic shift in pyro-lyzate composition occurred at T CHAR350°C:the relative abundance of DHB diminished,with a concomitant increase in phenols(from ca.10%to50%),as well as benzenes,PAH and other compounds(Fig.3).Also,the relative contribution of THB de-creased further.The results are indicative of strong B ring dehydr-oxylation at350°C.At T CHAR400°C,a further decrease in DHB contribution and increased relative abundance of benzenes and PAH were observed.The high biphenyl/naphthalene ratio may be speciﬁc for the pyrolyzate of CT-derived BC,as it is usually much lower in the pyrolyzate of char obtained from lignocellulose(Kaal et al.,2009).At T CHAR450°C,phenols decreased while the relative abundance of benzenes increased towards60%and that of PAHs to-wards10%,suggesting the loss of most of the OH groups from theB Fig.5.Total ion chromatograms of uncharred(control)and charred(200–600°C)CT,from THM–GC–MS.ring.The relatively weak signal for this sample (Table 1;Fig.2)sug-gested that a signiﬁcant proportion of the CT was converted to non-pyrolyzable polycondensed aromatics.After charring at 600°C the phenolic pyrolysis products and the possible products of the C ring (acetylacetone,acetone and acetic acid)were absent,while the benzenes and PAH had increased to 75%and 20%,respec-tively (Fig.3).This combination constitutes a typical set of pyroly-sis products from strongly charred biomass (Kaal et al.,2009;Fabbri et al.,2012).The general trends for experimental charring of CT as deter-mined with Py–GC–MS became apparent with PCA.In Fig.4,the pyrolysis products are plotted in PC1–PC2space.PC1explained 62%of the total variance and PC222%.PC1and PC2reﬂect the same process however,namely thermally-induced dehydroxylation:benzenes and PAH had positive loadings on PC1(recording increas-ing abundance with increasing T CHAR )while DHB and THB had neg-ative loadings (compounds showing an opposite trend of decreasing abundance with increasing T CHAR ).PC2separated the phenols from the other pyrolysis products:the phenols had a small contribution to the pyrolyzate at the lower and highest tempera-tures,while they dominated the pyrolyzates of the samples charred between 350and 400°C.The arrow in Fig.4represents the dehydroxylation pathway of CT with increasing T CHAR .The pro-cess is reﬂected in the THB/DHB,DHB/phenol and phenol/benzene ratios (not shown),which decreased signiﬁcantly with increasing T CHAR (P <0.001for all ratios).Under the experimental conditions of the present study,the thermal modiﬁcation of the CT B ring oc-curred predominantly between 300and 400°C.3.3.Charred condensed tannin composition:THM–GC–MSTHM–GC–MS total ion chromatograms are depicted in Fig.5.Similar to TQPA from Py–GC–MS,TQPA decreased with increasing T CHAR (Table 1).The THM products are listed in Table 3,with corresponding relative contributions to TQPA.The likely origin of the THM products was identiﬁed on the basis of the substitution pattern of the functional groups.As such,the THM products were grouped according to the number of O-containing functional groups (OFG).Furthermore,trimethoxybenzenes with the methoxyl groups in the m positions (methylated phloroglucinol derivatives)were assumed to originate from A ring moieties,while the trimethoxybenzenes with the methoxyl groups in the o positions (methylated pyrogallol derivatives)were assumed to originate from prodelphinidin B ring moieties.For the uncharred CT,major products from the A ring were 1,3,5-trimethoxybenzene and 2-methyl-1,3,5-trimethoxybenzene,while procyanidin and prodelphinidin B ring products were pres-ent mainly as methyl esters of 3,4-dimethoxybenzoic acid and 3,4,5-trimethoxybenzoic acid,respectively.These compounds have been found to be the dominant THM products of CT isolated from various plant species (Nierop et al.,2005).The presence of A ring products and absence of CH 2-bridged diaromatic (i.e.diphenylme-thane-based)products suggests that CT was readily depolymerized during THM.The exact location of depolymerization is unknown because it cannot be elucidated whether the Me group in 2-methyl-1,3,5-trimethoxybenzene originated from the C-4carbon in the same monomer or from a C-4carbon in the C ring of an adja-cent monomer.The fact that uncharred CT produced no detectable intermonomeric THM products implies that charring-induced depolymerization cannot be studied either.Parameters used by Nierop et al.(2005)to indicate the %of procyanidin B rings of CT were ‘‘PC-acid’’(dimethoxybenzoic acid,methyl ester/sum di-and trimethoxybenzoic acids,methyl esters;26.9%)and ‘‘PC-THM’’(based on all compounds related to di-and trihydroxy B rings;36.2%),are 49.4%and 34.2%,respectively,for the (uncharred)CT used isolated from Corsican pine used here.The cause of the large difference in the ‘‘PC-acid’’parameter may be of an analytical nature.The fact that the ‘‘PC-THM’’values,which were often closer to those determined with NMR (Nierop et al.,2005),were similar suggests that this parameter to estimate the %procyanidin B rings from THM–GC–MS is reproducible.Analogous to Py–GC–MS,the THM–GC–MS pattern from the CT charred at 200°C was similar to the uncharred CT (Fig.5).At T CHAR 300°C,a major decline was observed for 1,3,5-trimethoxybenzene and 2-methyl-1,3,5-trimethoxybenzene from the A ring (Fig.6),which coincided with an increase in relative contribution of most of the products with two or three adjacent methoxyl groups de-rived from CT B-rings.This is suggestive of a greater thermalstabil-Relative proportion (%of TQPA)of THM product groups from CT vs.charring temperature (200–600°C).0°C,control (uncharred CT);OFG refers to number containing functional groups;PAH,polycyclic aromatic hydrocarbon.Note differences in y -axis scaling.ity of B rings than A rings.Between T CHAR300and400°C,the rela-tive contribution of compounds with three and four OFG de-creased,that of two OFG maximized,while that of compounds with only one OFG increased.The trend was especially strong for the compounds with three o methoxyl groups,suggesting thor-ough thermal rearrangement of prodelphinidin B rings in this tem-perature range.At higher charring temperatures,the proportions of benzene,alkyl benzenes and PAH increased strongly,while the proportions of the other compounds decreased.Like the benzenes, benzoic acid methyl ester increased progressively with increasing T CHAR,but it is not clear whether the carboxylic group was formed upon oxidation during the charring experiment or upon Cannizz-aro reactions during THM(Hatcher and Minard,1995;Tanczos et al.,1997).Relatively intact CT A ring products were still recog-nized at T CHAR450°C(R1,3,5-trimethoxybenzenes>10%of TQPA), suggesting that THM–GC–MS might allow unequivocal identiﬁca-tion of CT markers in weak/moderately charred BC.McKinney et al.(1996)identiﬁed these THM products from cutan isolated from Agave americana.Apart from its presence in CAM plants only (Boom et al.,2005),a possible interference from cutan-derived 1,3,5-trimethoxybenzenes would be recognized by the presence of methylated aliphatic compounds including fatty acid methyl es-ters.More importantly,these1,3,5-trimethoxybenzenes are not formed upon THM of lignin(e.g.Chefetz et al.,2002;Nierop and Filley,2008;Shadkami and Helleur,2010),a more likely interfering component in plant-derived BC.No O-substituted PAH such as methoxynaphthalenes were de-tected,suggesting that thorough elimination of functional groups preceded the polycondensation reactions.Finally,methylated ben-zene polycarboxylic acids(with three or more carboxyl groups) found among the THM products of aged charcoal(Kaal et al., 2008)were not detected,probably because the necessary oxidation reactions occur during aging in soil and not during heat treatment under limited O2availability.The PC1(58%)–PC2(22%)plot of the THM products showed a similar distribution according to hydrox-ylation pattern(Fig.7).The arrow indicates the progressive loss of OFG with increasing T CHAR.Unsurprisingly,the main difference between Py–GC–MS and THM–GC–MS was the higher abundance of OFG among THM prod-ucts,independent of charring intensity,conﬁrming the protection of functional groups resulting from TMAH derivatization and the loss and/or poor detection of polar compounds using conventional Py–GC–MS.4.ConclusionsThe charring of CT caused progressive dehydroxylation at T CHAR6400°C(under the conditions of the present study)and polyaromatization in the higher temperature range at T CHAR400–600°C.Based on Py–GC–MS,it is suggested that pyrogallol and, more tentatively,catechol derivatives may act as indicators of CT-derived BC formed at low temperature,while a high relative abundance of biphenyl might be indicative of a signiﬁcant CT con-tribution in more severely charred material.Py–GC–MS is not suit-able for detection of A ring products.From THM–GC–MS,initial A ring degradation occurred at lower temperatures than B ring deg-radation.Nonetheless,the signiﬁcant contribution of1,3,5-tri-methoxybenzenes from the phloroglucinol A ring up to T CHAR 450°C suggested that these compounds can be used to distinguish between lignin and CT-derived BC in weakly/moderately charred BC samples.The results show that CT is a possible source of pheno-lic moieties in BC and provide a framework for estimating the de-gree of thermal degradation of CT based on the functional group distribution of Py–GC–MS and THM–GC–MS products.Incubation experiments using this CT are currently being developed,aimed at determining the effects of CT charred at different temperatures on organic matter mineralization.AcknowledgmentsWe thank Carmen Pérez Llaguno(Universidade de Santiago de Compostela)for elemental analysis and two anonymous reviewers for their time and comments.Associate Editor—S.DerenneReferencesBaldock,J.A.,Smernik,R.J.,2002.Chemical composition and bioavailability of thermally altered Pinus resinosa(red pine)anic Geochemistry33, 1093–1109.Boom,A.,Sinninghe Damsté,J.S.,De Leeuw,J.W.,2005.Cutan,a common aliphatic biopolymer in cuticles of drought-adapted anic Geochemistry36, 595–601.Braadbaart,F.,Boon,J.J.,Veld,H.,David,P.,Van Bergen,P.F.,boratory simulations of the transformation of peas as a result of heat treatment:changes of the physical and chemical properties.Journal of Archaeological Science31, 821–833.Challinor,J.M.,2001.Review:the development and applications of thermally assisted hydrolysis and methylation reactions.Journal of Analytical and Applied Pyrolysis61,3–34.Chefetz, B.,Salloum,M.J.,Deshmukh, A.P.,Hatcher,P.G.,2002.Structural components of humic acids as determined by chemical modiﬁcations and13C NMR,pyrolysis-,and thermochemolysis–gas chromatography/mass spectrometry.Soil Science Society of America Journal66,1159–1171.De la Rosa,J.M.,Knicker,H.,López-Capel,E.,Manning,D.A.C.,González-Pérez,J.A., González-Vila,F.J.,2008.Direct detection of black carbon in soils by py–GC–MS, 13C NMR spectroscopy and thermogravimetric techniques.Soil Science Society of America Journal72,258–267.Fabbri, D.,Torri, C.,Spokas,K.A.,2012.Analytical pyrolysis of synthetic chars derived from biomass with potential agronomic application(biochar).Relationships with impacts on microbial carbon dioxide production.Journal of Analytical and Applied Pyrolysis93,77–84.Fierer,N.,Schimel,J.P.,Cates,R.G.,Zou,J.,2001.Inﬂuence of balsam poplar tannin fractions on carbon and nitrogen dynamics in Alaskan taigaﬂoodplain soils.Soil Biology and Biochemistry33,1827–1839.Filley,T.R.,Nierop,K.G.J.,Wang,Y.,2006.The contribution of polyhydroxyl aromatic compounds to tetramethylammonium hydroxide lignin-based anic Geochemistry37,711–727.Galletti,G.C.,Reeves,J.B.,1992.Pyrolysis/gas chromatography/ion-trap detection of polyphenols(vegetable tannins):preliminary anic Mass Spectrometry27,226–230.Galletti,G.C.,Modafferi,V.,Poiana,M.,Bocchini,P.,1995.Analytical pyrolysis and thermally assisted hydrolysis–methylation of wine tannin.Journal of Agricultural and Food Chemistry43,1859–1863.González-Pérez,J.A.,González-Vila,F.J.,Almendros,G.,Knicker,H.,2004.The effect ofﬁre on soil organic matter–a review.Environment International30,855–870.THM products plotted in PC1–PC2space(from PCA).OFG refers to numberO-containing functional groups;PAH,polycyclic aromatic hydrocarbon.Theindicates the major trend in dominant THM products with increasing charringtemperature.47(2012)99–108107。

1-s2.0-S0306261907001742-main

Application of the Miller cycle to reduce NO x emissionsfrom petrol enginesYaodong Wang a,b,*,Lin Lin c ,Shengchuo Zeng b ,Jincheng Huang b ,Anthony P.Roskilly a ,Yunxin He b ,Xiaodong Huang b ,Shanping Li daThe Sir Joseph Swan Institute for Energy Research,Newcastle University,Newcastle upon Tyne,NE17RU,United KingdombMechanical Engineering College,Guangxi University,Nanning,Guangxi 530004,China cNanning College for Vocational Technology,Nanning,Guangxi 530003,ChinadGuangxi University of Technology,Liuzhou,545006,ChinaAccepted 26October 2007Available online 7February 2008AbstractA conceptual analysis of the mechanism of the Miller cycle for reducing NO x emissions is presented.Two versions of selected Miller cycle (1and 2)were designed and realized on a Rover ‘‘K ”series 16-valve twin-camshaft petrol engine.The test results showed that the application of the Miller cycle could reduce the NO x emissions from the petrol engine.For Miller cycle 1,the least reduction rate of NO x emission was 8%with an engine-power-loss of 1%at the engine’s full-load,compared with that of standard Otto cycle.For Miller cycle 2,the least reduction rate of NO x emission was 46%with an engine-power-loss of 13%at the engine’s full-load,compared with that of standard Otto cycle.Ó2007Elsevier Ltd.All rights reserved.Keywords:Petrol engine;Miller cycle;NO x emission1.IntroductionIt has been more than a century since petrol engines were ﬁrst and widely used as primary movers for human activities,such as transportation and stand-by power generation.The technologies to design and to make petrol engines are well developed.But environmental concerns since the 1970s have made the control of engine emissions a challenge for the engine industry.Engineers and researchers have taken numerous mea-sures to reduce engine emissions and to comply with restrictions on the quality and quantity of emissions allowed in diﬀerent applications.The need to meet the emissions legislation means that it is appropriate con-tinuously to investigate the ways of reducing emissions without compromising engine-eﬃciency or increasing the cost of manufacturing engines.0306-2619/$-see front matter Ó2007Elsevier Ltd.All rights reserved.doi:10.1016/j.apenergy.2007.10.009*Corresponding author.Address:Newcastle University,The Sir Joseph Swan Institute,Newcastle upon Tyne NE17RU,United Kingdom.Tel.:+4401912464934;fax:+4401912464961.E-mail address:y.d.wang@ (Y.Wang).Available online at Applied Energy 85(2008)463–474/locate/apenergyAPPLIED ENERGYThe main gaseous emissions from petrol engines are hydrocarbon (HC),carbon monoxide (CO),carbon dioxide (CO 2)and nitrogen oxides (NO x ,i.e.NO and NO 2).Among them,NO x is the most harmful gas that needs to be minimized.Currently there are two ways to reduce NO x emissions:one way is reducing NO x at source,such as exhaust-gas recirculation or homogenous combustion.This method is preferred from the view point of cost.Another way is after-treatment.This is an eﬀective but expensive way to reduce NO x emissions.In order to reduce the NO x emissions at source,it is necessary to know the mechanism of NO x formation in the engine cylinder.The factors that inﬂuence the formation of NO x in engines are:(a)the peak ﬂame-tem-perature during the combustion process,(b)the duration of the heat-release process,and (c)the air–fuel ratio.Among these factors,the peak ﬂame-temperature in the cylinder is the key factor.If the highest temperature of the ﬂame is reduced,the amount of NO x formed in the cylinder will be less.Consequently,the NO x emissions will be reduced.Thus,searching for a way to lower or to control the peak ﬂame-temperature in the engine’s cylinder is one of the main aim for engine engineers and scientists.The Miller cycle was ﬁrst proposed by ler in 1947.The proposal was for the use of early intake valve closing (EIVC)to provide internal cooling before compression so as to reduce the compression work [1].Miller further proposed increasing the boost of the inlet charge to compensate for the reduced inlet duration [2].The cycle that Miller proposed is a cold cycle which has allowed an increase in engine performance with an upraise of the knocking threshold.At that time,the Miller cycle was focused on improving the thermal eﬃciency of engine [3–10].This is still the aim [11–15].Since the Miller cycle is a cold cycle,there is the possibility to apply it to reduce the combustion temperatures in engines thus reducing the NO x formation and emissions.The objective of this study is to investigate experimentally the feasibility of the application of the Miller cycle in order to reduce NO x emissions from petrol engines.2.The concept of Miller cycle 2.1.Description of Miller cycleFor the Miller cycle,the expansion-ratio exceeds its compression-ratio [15],that is,the eﬀective expansion stroke of the engine is longer than the compression stroke.A comparison of the standard Otto cycle with the Miller cycle is shown in Fig.1.Assuming the cylinder pressure at the starting point 0is P 0,the volume is V 0,the swept volume of cylinder for Otto cycle is V c and for Miller cycle is V 0c .As shown in Fig.1a,the work processes of Otto cycle are:intake process 0?1,compression process 1?2,combustion and expansion process 2?3?4,and exhaust process 4?1?0.For the cycle,theNotation M 1Miller cycle 1M 2Miller cycle 2n engine speed (r/min)P pressure in the cylinder (kPa)P 0ambient pressure (kPa)V volume of cylinder (m 3)V 0clearance volume (m 3)V c swept volume of Otto cycle (m 3)V 0c swept volume of Miller cycle (m 3)D Pe power diﬀerence between the Otto cycle and the Miller cycle (kW)D Tr exhaust-temperature diﬀerence between the Otto cycle and the Miller cycle (°C)e D NO x relative NO x emission diﬀerence between the Otto cycle and the Miller cycle e D Pe relative power diﬀerence of Otto cycle from that of the Miller cyclee D Trrelative exhaust-temperature diﬀerence between the Otto cycle and the Miller cycle464Y.Wang et al./Applied Energy 85(2008)463–474Y.Wang et al./Applied Energy85(2008)463–474465compression-ratio is identical to the expansion-ratio;a higher expansion-ratio causes a higher compression-ratio.However,the Miller cycle allows the compression-and expansion-ratios to be preset independently,as shown in Fig.1b.The work processes are:intake process0?1a?1;then an additional‘‘intake blow-back”process1?1a,which is the main diﬀerence between the Miller cycle and the Otto cycle;compression process 1a?2;combustion and expansion process2?3?4?4a;and exhaust process4a?1?1a?0.From the P–V diagram of the Miller cycle,it can be seen that a higher engine-eﬃciency is expected with an increased expansion-ratio because more heat is changed to mechanical power.This was the original idea behind the Miller cycle.466Y.Wang et al./Applied Energy85(2008)463–4742.2.Basic idea of the Miller cycle to reduce NO x emissionsAs mentioned above,NO x is one of the most harmful gases emitted from engines and the main cause of NO x formation is the peakﬂame-temperature in the engine cylinder during the combustion.The Miller cycle is a‘‘cold cycle”.The application of this‘‘cold”characteristic may reduce the temperature at the end of the compression process(at point2in the P–V diagram).Thus it reduces the temperature at the end of the com-bustion process(point3in the P–V diagram).Therefore,it reduces the NO x emissions.This is the basic idea of the application of the Miller cycle to reduce the NO x emission from petrol engines.Fig.2presents the P–V diagram for this concept.Cycle0?1?2?3?4?1?0is the standard Otto cycle.Cycle0?1?1a?2a?3a?4a?1?0is the Miller cycle.The intake valve is kept open during a portion of the compression stroke.Some of intake air into the cylinder is rejected.Thus the amount of intake air into the cylinder is relatively less than for the Otto cycle and this reduces the eﬀective compression-ratio.At the end of the compression stroke,the pressure and temperature in the cylinder are lower than those of stan-dard Otto cycle.The combustion temperature is then lower;this may result in less NO x formation in the cyl-inder of engine.2.3.Main methods to realize the Miller cycleThere are three main methods to realize a Miller cycle in practice[5–8]:(a)installing a rotating valve between intake manifold and intake valve(on the cylinder head)to control the intake air quantity–early rotary-valve closing(ERVC);(b)closing the intake valve before the termination of the intake stroke–early intake valve closing(EIVC);and(c)keeping the intake valve open during a portion of the compression stroke, thus rejecting part of the charge and reducing the net compression-ratio–late intake valve closing(LIVC–as shown in Fig.2).For this experimental study,the LIVC version of the Miller cycle was selected.A schematic valve timing diagram of the LIVC is shown in Fig.3.Two versions of the LIVC Miller cycle were designed and tested; the detail parameters are presented in Section3.6.3.Experimental rig,instrumentation and test plan3.1.The engineA Rover‘‘K”series16-valve twin-camshaft petrol engine,type K-161400TBI,made by the Rover Group Ltd.in1991,shown Fig.4,was used for the experimental investigation.It has a1397cm3displacement,max-imum power70.8kW/6250r/min(torque106.7Nm),maximum torque124Nm/4000r/min,equipped for Rover200&400series cars.Y.Wang et al./Applied Energy85(2008)463–4744673.2.The dynamometer(see Fig.5)A Heenan Dynamatic Dynamometer MK1,made by Froude Consine Ltd.,was used to measure the engine performance:i.e.its torque,power and fuel consumption.3.3.Emission analyzersFour exhaust-gas analyzers,as shown in Fig.6,made by Analytical Development Company Ltd.(Hoddes-don,Hertfordshire,EN110DB,England),were used to analyze the exhaust emissions(carbon monoxide,car-bon dioxide,hydrocarbon and nitrogen oxides)from the engine.Prior to testing,the analyzers were calibrated separately by using the special sample gases supplied by BOC Ltd.3.4.Pressure and temperature measurementPressures were measured at the air-inlet manifold,for the engine oil at the outlet of the oilﬁlter,and the ambient-air pressure was measured by a barometer.Thermocouples type K (which have a temperature range from À200°C to 1200°C)were used to measure the temperature at the following positions on the engine:air-inlet,exhaust-gas,engine oil,and the engine’s cooling-water inlet andoutlet.Fig.5.Dynamometer.Fig.6.Emission analyzers.468Y.Wang et al./Applied Energy 85(2008)463–474Y.Wang et al./Applied Energy85(2008)463–474469 3.5.The test rigFig.7presents the schematic design of the test rig for the experimental study.Fig.8shows the completed test rig in the laboratory.470Y.Wang et al./Applied Energy85(2008)463–4743.6.Experimental planA test plan was designed to carry out the engine tests on the original Otto cycle and two Miller cycles.For comparison,the intake throttle wasﬁxed at the maximum open position for all the tests.There were no changes for the other engine systems,except for the intake valve timing.The running range of the engine was from2000r/min to6250r/min.Two versions of the Miller cycle were designed and tested as follows:ler1:the intake valve closed15°later than that of original Otto cycle;ler2:the intake valve closed30°later than that of original Otto cycle.The whole experimental plan was realized in two stages:(i)running engine on standard Otto cycle;and(ii) running engine on the two Miller cycles.Each test was repeated3times to make sure the data were reliable. The detailed test plan is listed in Table1.4.Test results and discussionThe test results of the engine-power output,brake speciﬁc fuel-consumption(BSFC),exhaust-gas temper-ature and the NO x emissions for the original Otto cycle and the two Miller cycles are shown in Figs.9–16.The engine’s brake engine-power outputs at diﬀerent engine speeds from the three cycles are presented in Fig.9.The engine’s power outputs of Miller cycle1were almost the same as those of the Otto cycle;the Table1The experimental planEngine speed(r/min)Cycle testedOtto cycle Miller cycle1Miller cycle2Time tested2000Three Three Three3000Three Three Three3500Three Three Three4000Three Three Three4500Three Three Three5000Three Three Three5500Three Three Three6250Three Three ThreeY.Wang et al./Applied Energy85(2008)463–474471472Y.Wang et al./Applied Energy85(2008)463–474Y.Wang et al./Applied Energy85(2008)463–474473diﬀerences were from0.0to1.2kW.The diﬀerences between Miller cycle1and Otto cycle were from0%to 2%,as shown in Fig.10.For Miller cycle2,the engine-power outputs at diﬀerent engine speeds were much less than those of original Otto cycle.The diﬀerences of power outputs were between4.7and10.8kW,as shown in Fig.9.The relative diﬀerences were from13%to22%for the Miller cycle2compared with those of Otto cycle.The results are also presented in Fig.10.The engine’s brake speciﬁc fuel-consumption related to the power outputs at diﬀerent engine speeds for the three cycles are shown in Fig.11.For the Miller cycle1,the BSFCs were from2.5to28.2g/kWh,higher than those of the Otto cycle.The relative diﬀerences were under8%in all the cases.The results are shown in Fig.12.For the Miller cycle2,the BSFCs were also higher than those of the Otto cycle,i.e.from57.5to146.6g/ kWh,which are also presented in Fig.11.The relative diﬀerences were from17%to44%,as shown in Fig.12.The exhaust-gas temperatures at the outlet of the engine’s exhaust-manifold related to the power outputs at diﬀerent engine speeds for the Otto cycle and the two Miller cycles are shown in Fig.13.The exhaust-gas tem-peratures for the Miller cycles at diﬀerent engine speeds were all lower than those of Otto cycle.For the Miller cycle1,as shown in Fig.13,the diﬀerences of exhaust-gas temperatures were from20°C to 62°C,compared with those of Otto cycle.The relative diﬀerences were from2%to11%–see Fig.14.For the Miller cycle2,compared with that of the Otto cycle,the diﬀerences of exhaust-gas temperatures were between45°C and112°C.The relative diﬀerences were from6%to19%–see Fig.14.The results of NO x emissions from the three cycles at diﬀerent engine speeds are presented in Fig.15.For the cycles tested,the NO x emissions from the Otto cycle were the highest;those from the Miller cycle1came second;and those from the Miller cycle2were the lowest.For the Miller cycle1,compared with the Otto cycle,the diﬀerence of NO x emissions ranged from130to 665ppm.The relative diﬀerences were from8%to51%.The results are shown in Figs.15and16.For the Miller cycle2,compared with the Otto cycle,the diﬀerences of NO x emissions were from360to 850ppm.The relative diﬀerences were from44%to69%.The results are also shown in Figs.15and16.From these results,it can be seen that the engine-power outputs of the Miller cycle1(M1)were nearly the same as those of the original Otto cycle;the exhaust-gas temperatures of M1were lower than those of the Otto cycle;and the NO x emissions were also lower than those of the Otto cycle.For the Miller cycle2(M2),the exhaust-gas temperatures were lower than those of M1and the Otto cycle; and the NO x emissions were much lower than those of the Otto cycle.The eﬀect of the Miller cycle in reducing the NO x emission is obvious,although the engine power outputs were much lower than those of the Otto cycle.The reason for the power-loss is because the late intake valve closure during the compression stroke led to some of the mixture of air and fuel being pushed out of the cylinder;this resulted in the charge being less than that of original Otto cycle.As a result,the engine-power outputs were reduced.474Y.Wang et al./Applied Energy85(2008)463–4745.Conclusions and recommendationThe investigation of the feasibility of applying the Miller cycle to petrol engines to reduce NO x emissions was completed.The results showed that it was feasible to apply the Miller cycle to petrol engines in order to reduce NO x emissions.For the two versions of the Miller cycles tested,the NO x emissions were less than those of the original Otto cycle.Of the two versions of the Miller cycle tested,Miller2is the better,in terms of the reductions of NO x emis-sion only.Of the two versions of the Miller cycle tested,Miller1is the better,in terms of both the reductions of NO x emissions and the engine-power outputs.For the two Miller cycles tested,the engine-power outputs were all less than those of the Otto cycle.This is due to there being less charge in the engine cylinder,which is a characteristic of Miller cycle.In order to make up for the charge losses as well as to make up for the power-losses,it is necessary to carry out an investigation on the application of a supercharger with an inter-cooler added to the above Miller cycles.A better engine performance with NO x reduction may then be able to be achieved. AcknowledgementsThe authors wish to thank Mr.Ian Pinks who helped set up the test rig for the experiments.The support of the Faculty of Computing,Engineering and Technology of Staﬀordshire University,UK is greatly appreciated.References[1]Miller RH.Supercharging and internal cooling cycle for high output.Trans ASME1947;69:453–7.[2]Miller RH,Lieberherr HU.The Miller supercharging system for diesel and gas engines operating characteristics,CIMAC,1957.In:Proceedings of the4th international congress on combustion engines,Zurich.June15–22;1957.p.787–803.[3]Okamoto K,Zhang FR,Shimogata S,Shoji F,Kanesaka H,Sakai H.Study of a Miller-cycle gas-engine for co-generation systems–eﬀect of a Miller cycle on the performance of a gas engine,vol.1171.1996:SAE Special Publications;1996,p.125–36.[4]Thring RH.Theﬂexible diesel engine.In:Proceedings of the international congress and exposition,Detroit,USA,1990.SAE PaperNo.900175.SAE Special Publications;1990,p.484–92.[5]Clarke D,Smith WJ.Simulation,implementation and analysis of the miller cycle using an inlet control rotary-valve,variable valveactuation and power boost,vol.1258(SAE,No.970336).SAE Special Publications;1997.p.61–70.[6]Shimogata S,Homma R,Zhang FR,Okamoto K,Shoji F.Study on Miller cycle gas engine for co-generation systems-numericalanalysis for improvement of eﬃciency and power.SAE Paper No.971709.SAE Special Publications;1997.p.61–67.[7]Franca ler cycle–outline and general considerations,Diesel Ricerche S.P.A.Technical report;1996.[8]Okamoto K,Zhang FR,Morimoto S,Shoji F.Development of a high-performance gas engine operating at a stoichiometric condition–eﬀect of Miller cycle and EGR.In:Proceedings of CIMAC congress1998Copenhagen.1998.p.1345–60.[9]Stebler H,Weisser G,Horler H,Boulouchos K.Reduction of NO x emissions of D.I.diesel engines by application of the Millersystem:an experimental and numerical investigation.SAE Paper No.960844.SAE Special Publications;1996.p.1238–48.[10]Ueda N,Sakai H,Iso N,Sasaki J.A naturally aspirated Miller cycle gasoline engine–its capability of emission,power and fueleconomy.SAE Paper No.960589.SAE Special Publications;1996.p.696–703.[11]Hatamura Koichi,Hayakawa Motoo,Goto Tsuyoshi,Hitomi Mitsuo.A study of the improvement eﬀect of the Miller-cycle on meaneﬀective pressure limit for high-pressure supercharged gasoline engines.JSAE Rev1997;18:101–6.[12]Hiroyuki Endo,Kengo Tanaka,Yoshitaka Kakuhama,Yasunori Goda,Takao Fujiwaka,Masashi Nishigaki.Development of thelean-burn Miller cycle gas engine(3-04).In:Proceedings of theﬁfth international symposium on diagnostics and modeling of combustion in internal combustion engines(COMODIA2001).Nagoya,Japan:July1–4;2001.p.374–81.[13]Fukuzawa Yorihiro,Shimoda Hiromi,Kakuhama Yoshitaka,Endo Hiroyuki,Tanaka Kengo.Development of a high eﬃciencyMiller cycle gas engine,Mitsubishi Heavy Industries Ltd..Tech Rev2001;38(3):146–50.[14]Wu Chih,Puzinauskas Paul V,Tsai Jung S.Performance analysis and optimization of a supercharged Miller cycle otto engine.ApplTherm Eng2003;23:511–21.[15]Al-Sarkhi A,Jaber JO,Probert SD.Eﬃciency of a Miller engine.Appl Energy2006;83:343–51.。

最全ASCII码对照表

ASCII码表

113
q
18
DC2
50
2
82
R
114
r
19
DC3
51
3
83
XHale Waihona Puke 115s20
DC4
52
4
84
T
116
t
21
NAK
53
5
85
U
117
u
22
SYN
54
6
86
V
118
v
23
TB
55
7
87
W
119
w
24
CAN
56
8
88
X
120
x
25
EM
57
9
89
Y
121
y
26
SUB
58
:
90
Z
122
z
27
ESC
59
;
91
[
123
‹
171
«
203
Ë
234
ê
140
Œ
172
¬
204
Ì
235
ë
141
173
205
Í
236
ì
142
Ž
174
®
206
Î
237
í
143
175
¯
207
Ï
238
î
144
176
°
208
Ð
239
ï
145
‘
177
±
209
Ñ
240

ASCII码表完整版

ESC FS GS RS US SP ! " # $ % & ' ( ) * + , . / 0 1 2 3 4 5 6 7 8 9 : ; < = > ? @ A B C D E F
(Escape) (File Separator) (Group Separator) (Request to Send)(Record Separator) (Unit Separator) (Space) (exclamation mark) (double quote) (number sign) (dollar sign) (percent) (ampersand) (single quote) (left/opening parenthesis) (right/closing parenthesis) (asterisk) (plus) (comma) (minus or dash) (dot) (forward slash)
EOY ENQ ACK BEL BS HT LF
传输结束询问字符承认报警退一格横向列表换行
SI DLE DC1 DC2 DC3 DC4 NAK
移位输入空格设备控制 1 设备控制 2 设备控制 3 设备控制 4 否定
SUB ESC FS GS RS US DEL
换置换码文字分隔符组分隔符记录分隔符单元分隔符删除
Text only 语言: Ascii 码表（全） ASCII Table (7-bit) (ASCII = American Standard Code for Information Interchange) Decimal ------000 001 002 003 004 005 006 007 008 009 010 011 012 013 014 015 016 017 018 019 020 021 022 023 024 025 026 Octal ------000 001 002 003 004 005 006 007 010 011 012 013 014 015 016 017 020 021 022 023 024 025 026 027 030 031 032 Hex -----000 001 002 003 004 005 006 007 008 009 00A 00B 00C 00D 00E 00F 010 011 012 013 014 015 016 017 018 019 01A Binary ----00000000 00000001 00000010 00000011 00000100 00000101 00000110 00000111 00001000 00001001 00001010 00001011 00001100 00001101 00001110 00001111 00010000 00010001 00010010 00010011 00010100 00010101 00010110 00010111 00011000 00011001 00011010 NUL SOH STX ETX EOT ENQ ACK BEL BS HT LF VT FF CR SO SI DLE DC2 DC4 NAK SYN ETB CAN EM SUB (Null char.) (Start of Header) (Start of Text) (End of Text) (End of Transmission) (Enquiry) (Acknowledgment) (Bell) (Backspace) (Horizontal Tab) (Line Feed) (Vertical Tab) (Form Feed) (Carriage Return) (Shift Out) (Shift In) (Data Link Escape) (Device Control 2) (Device Control 4) (Negative Acknowledgement) (Synchronous Idle) (End of Trans. Block) (Cancel) (End of Medium) (Substitute) Value

最全ASCII码对照表

ASCII码对照表以及各个字符的解释（精华版）

ASCII码对照表以及各个字符的解释（精华版）ASCII（American Standard Code for Information Interchange，美国信息互换标准代码）是一套基于拉丁字母的字符编码，共收录了128 个字符，用一个字节就可以存储，它等同于国际标准ISO/IEC 646。

ASCII 规范于 1967 年第一次发布，最后一次更新是在 1986 年，它包含了 33 个控制字符（具有某些特殊功能但是无法显示的字符）和95 个可显示字符。

ASCII 码对照表对控制字符的解释ASCII 编码中第 0~31 个字符（开头的 32 个字符）以及第 127 个字符（最后一个字符）都是不可见的（无法显示），但是它们都具有一些特殊功能，所以称为控制字符（ Control Character）或者功能码（Function Code）。

这 33 个控制字符大都与通信、数据存储以及老式设备有关，有些在现代电脑中的含义已经改变了。

有些控制符需要一定的计算机功底才能理解，初学者可以跳过，选择容易的理解即可。

下面列出了部分控制字符的具体功能：•NUL (0)NULL，空字符。

空字符起初本意可以看作为NOP（中文意为空操作，就是啥都不做的意思），此位置可以忽略一个字符。

之所以有这个空字符，主要是用于计算机早期的记录信息的纸带，此处留个 NUL 字符，意思是先占这个位置，以待后用，比如你哪天想起来了，在这个位置在放一个别的啥字符之类的。

后来呢，NUL 被用于C语言中，表示字符串的结束，当一个字符串中间出现 NUL 时，就意味着这个是一个字符串的结尾了。

这样就方便按照自己需求去定义字符串，多长都行，当然只要你内存放得下，然后最后加一个\0，即空字符，意思是当前字符串到此结束。

•SOH (1)Start Of Heading，标题开始。

如果信息沟通交流主要以命令和消息的形式的话，SOH 就可以用于标记每个消息的开始。

最全ASCII对应码表-键值

OCT(八进制)最全ASCII码对应表—与键盘按键对应值(二进)Bin (十进)Dec (十六进)Hex 缩写/字符解释0000 0000 0 00 NUL (null) 空字符0000 0001 1 01 SOH (start of handing) 标题开始0000 0010 2 02 STX (start of text) 正文开始0000 0011 3 03 ETX (end of text) 正文结束0000 0100 4 04 EOT (end of transmission) 传输结束0000 0101 5 05 ENQ (enquiry) 请求0000 0110 6 06 ACK (acknowledge) 收到通知0000 0111 7 07 BEL (bell) 响铃0000 1000 8 08 BS (backspace) 退格0000 1001 9 09 HT (horizontal tab) 水平制表符0000 1010 10 0A LF (NL line feed, new line) 换行键0000 1011 11 0B VT (vertical tab) 垂直制表符0000 1100 12 0C FF (NP form feed, new page) 换页键0000 1101 13 0D CR (carriage return) 回车键0000 1110 14 0E SO (shift out) 不用切换0000 1111 15 0F SI (shift in) 启用切换0001 0000 16 10 DLE (data link escape) 数据链路转义0001 0001 17 11 DC1 (device control 1) 设备控制1 0001 0010 18 12 DC2 (device control 2) 设备控制20001 0011 19 13 DC3 (device control 3) 设备控制3 0001 0100 20 14 DC4 (device control 4) 设备控制4 0001 0101 21 15 NAK (negative acknowledge) 拒绝接收0001 0110 22 16 SYN (synchronous idle) 同步空闲0001 0111 23 17 ETB (end of trans. block) 传输块结束0001 1000 24 18 CAN (cancel) 取消0001 1001 25 19 EM (end of medium) 介质中断0001 1010 26 1A SUB (substitute) 替补0001 1011 27 1B ESC (escape) 溢出0001 1100 28 1C FS (file separator) 文件分割符0001 1101 29 1D GS (group separator) 分组符0001 1110 30 1E RS (record separator) 记录分离符0001 1111 31 1F US (unit separator) 单元分隔符0010 0000 32 20 空格0010 0001 33 21 !0010 0010 34 22 "0010 0011 35 23 #0010 0100 36 24 $0010 0101 37 25 %0010 0110 38 26 &0010 0111 39 27 '0010 1000 40 28 (0010 1010 42 2A * 0010 1011 43 2B + 0010 1100 44 2C , 0010 1101 45 2D - 0010 1110 46 2E . 0010 1111 47 2F / 0011 0000 48 30 0 0011 0001 49 31 1 0011 0010 50 32 2 0011 0011 51 33 3 0011 0100 52 34 4 0011 0101 53 35 5 0011 0110 54 36 6 0011 0111 55 37 7 0011 1000 56 38 8 0011 1001 57 39 9 0011 1010 58 3A : 0011 1011 59 3B ; 0011 1100 60 3C < 0011 1101 61 3D = 0011 1110 62 3E >0100 0000 64 40 @0100 0001 65 41 A 0100 0010 66 42 B 0100 0011 67 43 C 0100 0100 68 44 D 0100 0101 69 45 E 0100 0110 70 46 F 0100 0111 71 47 G 0100 1000 72 48 H 0100 1001 73 49 I 0100 1010 74 4A J 0100 1011 75 4B K 0100 1100 76 4C L 0100 1101 77 4D M 0100 1110 78 4E N 0100 1111 79 4F O 0101 0000 80 50 P 0101 0001 81 51 Q 0101 0010 82 52 R 0101 0011 83 53 S0101 0101 85 55 U 0101 0110 86 56 V 0101 0111 87 57 W 0101 1000 88 58 X 0101 1001 89 59 Y 0101 1010 90 5A Z 0101 1011 91 5B [ 0101 1100 92 5C \ 0101 1101 93 5D ] 0101 1110 94 5E ^ 0101 1111 95 5F _ 0110 0000 96 60 ` 0110 0001 97 61 a 0110 0010 98 62 b 0110 0011 99 63 c 0110 0100 100 64 d 0110 0101 101 65 e 0110 0110 102 66 f 0110 0111 103 67 g 0110 1000 104 68 h 0110 1001 105 69 i0110 1011 107 6B k 0110 1100 108 6C l 0110 1101 109 6D m 0110 1110 110 6E n 0110 1111 111 6F o 0111 0000 112 70 p 0111 0001 113 71 q 0111 0010 114 72 r 0111 0011 115 73 s 0111 0100 116 74 t 0111 0101 117 75 u 0111 0110 118 76 v 0111 0111 119 77 w 0111 1000 120 78 x 0111 1001 121 79 y 0111 1010 122 7A z 0111 1011 123 7B { 0111 1100 124 7C | 0111 1101 125 7D } 0111 1110 126 7E ~0111 1111 127 7F DEL (delete) 删除键盘常用ASCII码（十进制表示值）ESC键VK_ESCAPE (27)回车键：VK_RETURN (13)TAB键：VK_TAB (9)Caps Lock键：VK_CAPITAL (20)Shift键：VK_SHIFT (16)Ctrl键：VK_CONTROL (17)Alt键：VK_MENU (18)空格键：VK_SPACE (/32)退格键：VK_BACK (8)左徽标键：VK_LWIN (91)右徽标键：VK_LWIN (92)鼠标右键快捷键：VK_APPS (93)Insert键：VK_INSERT (45)Home键：VK_HOME (36)Page Up：VK_PRIOR (33)PageDown：VK_NEXT (34)End键：VK_END (35)Delete键：VK_DELETE (46)方向键(←)：VK_LEFT (37)方向键(↑)：VK_UP (38)方向键(→)：VK_RIGHT (39)方向键(↓)：VK_DOWN (40)F1键：VK_F1 (112)F2键：VK_F2 (113)F3键：VK_F3 (114)F4键：VK_F4 (115)F5键：VK_F5 (116)F6键：VK_F6 (117)F7键：VK_F7 (118)F8键：VK_F8 (119)F9键：VK_F9 (120)F10键：VK_F10 (121)F11键：VK_F11 (122)F12键：VK_F12 (123)Num Lock键：VK_NUMLOCK (144) 小键盘0：VK_NUMPAD0 (96) 小键盘1：VK_NUMPAD0 (97) 小键盘2：VK_NUMPAD0 (98) 小键盘3：VK_NUMPAD0 (99) 小键盘4：VK_NUMPAD0 (100) 小键盘5：VK_NUMPAD0 (101) 小键盘6：VK_NUMPAD0 (102) 小键盘7：VK_NUMPAD0 (103) 小键盘8：VK_NUMPAD0 (104) 小键盘9：VK_NUMPAD0 (105) 小键盘.：VK_DECIMAL (110) 小键盘*：VK_MULTIPLY (106) 小键盘+：VK_MULTIPLY (107) 小键盘-：VK_SUBTRACT (109) 小键盘/：VK_DIVIDE (111) Pause Break键：VK_PAUSE (19) Scroll Lock键：VK_SCROLL (145)常见ASCII码的大小规则：0~9＜A~Z＜a~z1）数字比字母要小。

最全ASCII码对照表

最全ASCII码对照表Bin Dec Hex 缩写/字符解释0000 0000 0 NUL (null)空字符0000 0001 1 SOH (start of heading)标题开始0000 0010 2 STX (start of text)正文开始0000 0011 3 ETX (end of text)正文结束0000 0100 4 EOT (end of n)传输结束0000 0101 5 ENQ (enquiry)请求0000 0110 6 ACK (acknowledge)收到通知0000 0111 7 BEL (bell)响铃0000 1000 8 BS (backspace)退格0000 1001 9 HT (horizontal tab)水平制表符0000 1010 10 LF (NL line feed, new line)换行0000 1011 11 VT (vertical tab)垂直制表符0000 1100 12 FF (NP form feed, new page)换页0000 1101 13 CR (carriage return)回车0000 1110 14 SO (shift out)不可见换码0000 1111 15 SI (shift in)启用换码0001 0000 16 DLE (data link escape)数据链路转义0001 0001 17 DC1 (device control 1)设备控制1 0001 0010 18 DC2 (device control 2)设备控制2 0001 0011 19 DC3 (device control 3)设备控制3 0001 0100 20 DC4 (device control 4)设备控制4 0001 0101 21 NAK (negative acknowledge)拒绝接收0001 0110 22 SYN (synchronous idle)同步空闲0001 0111 23 ETB (end of trans. block)传输块结束0001 1000 24 CAN (cancel)取消0001 1001 25 EM (end of medium)媒介结束0010 0000 32 SP (space)空格0010 0001 33 ! 叹号0010 0010 34 " 双引号0010 0011 35 # 井号0010 0100 36 $ 美元符0010 0101 37 % 百分号0010 0110 38 & 和号0010 0111 39 ' 单引号0010 1000 40 ( 左括号0010 1001 41 ) 右括号0010 1010 42 * 星号0010 1011 43 + 加号0010 1100 44 , 逗号0010 1101 45 - 减号/破折号0010 1110 46 . 句号0010 1111 47 / 斜杠0011 0000 48 0 零0011 0001 49 1 一0011 0010 50 2 二0011 0011 51 3 三0011 0100 52 4 四0011 0101 53 5 五0011 0110 54 6 六0011 0111 55 7 七0011 1000 56 8 八0011 1001 57 9 九0100 0001 65 A 大写字母A0100 0010 66 B 大写字母B 0100 0011 67 C 大写字母C 0100 0100 68 D 大写字母D 0100 0101 69 E 大写字母E 0100 0110 70 F 大写字母F 0100 0111 71 G 大写字母G 0100 1000 72 H 大写字母H 0100 1001 73 I 大写字母I 0100 1010 74 J 大写字母J 0100 1011 75 K 大写字母K 0100 1100 76 L 大写字母L 0100 1101 77 M 大写字母M 0100 1110 78 N 大写字母N 0100 1111 79 O 大写字母O 0101 0000 80 P 大写字母P 0101 0001 81 Q 大写字母Q 0101 0010 82 R 大写字母R 0101 0011 83 S 大写字母S 0101 0100 84 T 大写字母T 0101 0101 85 U 大写字母U0101 0110 86 V 大写字母V0101 0111 87 W 大写字母W0101 1000 88 X 大写字母X0101 1001 89 Y 大写字母Y0101 1010 90 Z 大写字母Z0111 1111 127 DEL (delete)删除以上这些码和字符都是二进制编码，由0和1组成。

1-s2.0-S0360544213007809-main

Unveiling the mystery of Combined Heat&Power(cogeneration) Aviel Verbruggen a,*,1,Pierre Dewallef b,Sylvain Quoilin b,Michael Wiggin ca University of Antwerp,Belgiumb Energy Systems Research Unit,University of Liège,Belgiumc P.Eng J Michael Wiggin Consulting Inc.,Ottawa,Canadaa r t i c l e i n f oArticle history:Received29April2013Received in revised form12September2013Accepted13September2013Available online5October2013Keywords:CHP merit and qualityDesign power-to-heat ratioVirtual bliss pointElectricity e Heat production possibility set CHP paradox a b s t r a c tThe article unveils the mystery of cogeneration.Cogeneration is an add-on or embedded activity in thermal power plants,with as merit the use of part or whole of their point source heat exhausts.EU’s talk of“high-efﬁciency cogeneration”is an unfounded transfer of responsibility from the hosting thermal power generation plant onto CHP(Combined Heat&Power)activity.The quality of a CHP activity is univocally deﬁned by its design power-to-heat ratio s,a tombstone parameter derived from the design characteristics of the power plant.A thermal power plant may house more than one cogeneration ac-tivity.Identifying s requires positioning the bliss point in the electricity e heat production possibility set of the cogeneration activity.The bliss point is where after electric output is maximized,the sum of that output and the maximum recoverable quantity of heat occurs.Once CHP’s mystery of virtual bliss points is unveiled,the proper s are found.With known s by CHP activity,the quantity of cogenerated electricity is reliably assessed as best indicator of cogeneration performance.Our analysis is applicable on all relevant thermal power cycles that host CHP activities,and illustrated with a numerical example.Our lean method is necessary and sufﬁcient for proper CHP regulation.Ó2013Elsevier Ltd.All rights reserved.1.IntroductionCogeneration or CHP(Combined Heat&Power)is as old as its natural cradle,the thermal power plant.CHP is applied in thermal power plants employing diverse technologies and ranging from a few kW to a few hundreds of MW[1].Cogeneration diffusion in countries with similar economies is uneven,due to diverging en-ergy policies and related regulations[2,3].Dedicated sector orga-nizations(COGEN Europe,Euroheat&Power,International District Energy Association)support CHP deployment.The overwhelming breakthrough has not yet arrived.CHP is not fancy.Now and then,it is embraced by policy circles[4],kindling the hope for a boost of its application.Public policy in favor of efﬁcient fuel use,argues sup-port for cogeneration.This was intended by the EU CHP directive 2004/8/EC[5],but not realized by lack of effective and efﬁcient regulation.The EU[6]admitted that the2004CHP directive“failed to fully tap the energy saving potential”,but shows no assessment of theﬂaws in its regulation.The EU continues the2004frame-work,now incorporated in the Energy Efﬁciency Directive[7],without any improvement in answering the essential questions that impede improved regulation of cogeneration activity and its support:What is quality of CHP?What is CHP merit?How exactly to monitor and measure CHP performance?A partial remedy was suggested by CEN(European Committee for Standardization)[8], but failed on crucial points[9].The adage of this article is”everything should be made as simple as possible,but not simpler”.We care extremely about didactic transparency in communicating insights on the paradoxes of joint electricity e heat generation processes[10].Cogeneration only ex-ists when heat from the plant is recovered and used(what supports the idea of‘priority to heat’);yet net power output always should be maximized(‘priority to power’).This double priority is also called the CHP paradox.Effective communication is based on clear terminology,now missing in CHP’s world.It starts with the proper deﬁnition of what cogeneration/CHP is,of the power-to-heat ratios,of cogenerated electricity,etc.We add a few essential concepts to develop our analysis of CHP for unveiling its mystery:Electricity e Heat(E e Q) production possibility sets,and bliss points[9,11].We also invoke vocabulary from the environmental sciences,like point source and nonpoint source pollution[12].The article is developed along the logic summarized in the ab-stract.Section2deﬁnes CHP or cogeneration as an activity added*Corresponding author.Prinsstraat13;BE2000Antwerp,Belgium.Tel.:þ32476 888239;fax:þ3232654420.E-mail address:aviel.verbruggen@ua.ac.be(A.Verbruggen).1www.avielverbruggen.be.Contents lists available at ScienceDirectEnergyjournal h omepage:w/locate/energy0360-5442/$e see front matterÓ2013Elsevier Ltd.All rights reserved./10.1016/j.energy.2013.09.029Energy61(2013)575e582on or embedded in a thermal power generation process.Fig.1il-lustrates that CHP activity may convert part or all of the point source (and so recoverable)thermal pollution of the power plant into used heat.This leads to the proper de ﬁnition of CHP being the recovery and use of all or part of the point source heat exhaust,otherwise being rejected to the ambient environment,by a thermal power generation plant.CHP is comparable to other environmental mitigation activities.CHP activity is not responsible for the power conversion ef ﬁciency of the hosting thermal power plant.EU ’s talk of “high-ef ﬁciency cogeneration ”and its “Primary Energy Saving ”approach are unfounded transfers of responsibility from the host-ing thermal power generation plant onto CHP activity.Section 3explains that the design power-to-heat ratio of a CHP activity par-allels the electricity conversion ef ﬁciency of the hosting power cycle.It shows that the design ratio is the necessary and suf ﬁcient indicator of CHP quality.For identifying the proper design power-to-heat ratios,the positioning of bliss points is necessary.Here CHP analysts go astray when they overlook that most bliss points in practical CHP applications are virtual.The bliss point is where after electric output is maximized,the sum of this maximum and the maximum recoverable quantity of heat is reached (CHP paradox).Section 4states the basic merit of CHP activity being the use of part or all of a thermal power plant ’s point source heat exhaust,reducing heat rejection to the environment,and avoiding the use of other energy sources to obtain the used heat.Yet,the quantity of used heat is not adopted as the proper indicator of CHP perfor-mance because this implies incentives to downgrade a (expensive)power plant to the supply of heat that less expensive heat plants can deliver.The proper indicator is the quantity of cogenerated electricity,being the product of the design power-to-heat ratio and the recovered quantity of heat.As such this indicator overarches the CHP paradox,because the more heat is recovered and the more electricity is generated,the better scores the indicator.Section 5offers applied analysis.With the help of ﬁve graphs,the concepts and indicators proposed in the previous sections are implemented for all major power generation cycles:gas turbines,internal com-bustion engines,and extraction-condensing and backpressure steam turbines.Classing the cycles by temperature of their point source heat exhausts separates CHP activities without impact on the power output of the plant (e.g.CHP on reciprocating engines or gas turbines),from the ones with impact (e.g.CHP on steam tur-bines).Section 6is a short numerical example of the methods explained in Section 5.A few comments on the regulation of cogeneration activities are offered in Section 7,mainly recom-mending caution on the perverse impacts of the EU ’s externalbenchmark approach,because the latter leads to unfounded “high-ef ﬁciency ”calls.A conclusion is added in Section 8.Because the analysis breaks ground on an accurate de ﬁnition of what cogeneration really is,and because several basic concepts (electricity e heat production possibility sets,real and virtual bliss points,design power-to-heat ratios)are explained,perseverance and patience are requested from the reader to process the consecutive sections.Some proof readers of the article get the “eureka ”by the numerical example of Section 6,but it is not possible to provide the example without prior description of the concepts and methods.2.CHP is an activity added on/embedded in a thermal power generation processIn a thermal power generation plant,fuel is converted into a high temperature heat ﬂow,partly turned into power,and partly discarded from the process as residual heat at lower temperature [13](Fig.1,left side).The power obtained from steam turbines,gas turbines,or internal combustion engines,is convertible into elec-tricity.2Heat rejection to the ambient environment is called ther-mal pollution [12].Pollution is often classed as point source or nonpoint source pollution.A point source is a single identi ﬁable localized source,from which ﬂux or ﬂow is emanating,manageable for capture,treatment,or storage.Nonpoint sources cause diffuse emissions,spreading and mixing with ﬂows and mass in the ambient environment.In thermal power generation cycles,point sources are the con-densers at the end of the steam expansion in steam turbines,out-lets of gas turbines,and radiators for engine mantle and oil cooling.Flue gas stacks are thermal point sources when heat is still recov-erable,or are diffuse sources when non-recoverable.Heat radiation at various parts of the process is also considered non-recoverable.CHP or cogeneration is the recovery and use of all or part of the point source heat exhaust,otherwise being rejected ,by a thermal power generation plant.Fig.1represents CHP activity as a valve splitting the point source heat exhaust ﬂow in a used andrejectedFig.1.Thermal power generation:CHP is the recovery of (a share of)the point source heat exhaust.2Few applications are direct drive (for example running a compressor on a turbine ’s shaft power),except for delivering torque or thrust for transport (vehicles,ships,planes).Fuel cells also convert (hydrogen)fuel in power and heat,but are not widely applied yet.A.Verbruggen et al./Energy 61(2013)575e 582576share:in position0no heat is used/all heat is rejected to the ambient environment;in position0.3thirty percent of the heat is used/seventy percent is rejected;in position0.6sixty percent is used/forty percent rejected;in position1all heat is used/no heat is rejected to the environment.The continuum of positions reﬂects all imaginable operational CHP activities.In practice CHP activity may be constrained by the design and the availability of speciﬁc facilities for recovering or for rejecting heat.For example,a steam turbine thermal power plant may be designed as a condensing power unit without possibility of using the point source heat exhaust(ﬁxed at position0);when designed as full backpressure unit it isﬁxed at position1and cannot reject point source heat to the ambient environment;when facilities are installed for recovering a maximum of thirty percent of the point source heat exhaust,CHP activity can range over all positions be-tween0and0.3,but not beyond the latter.In the latter case, confusion arises,and is strengthened by dense but misleading terminology.The physical phenomenon“CHP/cogeneration activity added on or embedded in a thermal power generation plant”is mostly shortcut as“CHP/cogeneration plant”.3The shortcut obscures that CHP is an added or embedded facility to recover point source thermal pollution;as such CHP is similar to other mitigation techniques(for example scrubbers removing SO2from theﬂue gases of coal plants).The properties of the polluting installation may affect the mitigation facility,but the latter carries no re-sponsibility for those properties.Unfounded carrying over of re-sponsibility from the hosting thermal power generation plant onto the CHP activity is the EU’s and others talk about“high-efﬁciency cogeneration”[7].The merit of CHP activity is in recovering as much as possible of the point heat source exhaust.CHP activity is not responsible for the power conversion efﬁciency of the hosting thermal power plant.3.The quality of CHP and how to measure itThe quality of a thermal power generation process is the efﬁ-ciency h in generating power from the fuel,measured by the ratio E/ F.In case of CHP,the cogeneration efﬁciency(EþQ)/F is often used as efﬁciency yardstick.This yardstick assigns equal weight and value to electricity and heat.However,electricity and heat do not have the same value.From the thermodynamic point of view, electricity can be entirely converted into heat or work while the conversion of heat into work is limited by the second principle of thermodynamics.From the economic point of view,expensive power plants are required to produce high-quality power while low temperature heat can be produced with not so expensive com-bustion facilities(burners,furnace,boilers,etc.).Optimizing a thermal power cycle with cogeneration activities requires maxi-mizing the output of electricity per unit of heat produced for given fuel inputs.Applying theﬁrst principle of thermodynamics on a thermal power plant leads to F¼EþQþL.When the diffuse losses L are stabilized at their minimum level,the efﬁciency ratio E/F is paral-leled by the ratio E/Q called the design power-to-heat ratio and denoted s.The latter is a crucial variable for understanding cogeneration.When h goes up,so does s,and vice versa.The quality of thermal power generation processes is reﬂected by the capacity to generate relatively more electricity than heat,with the ratio E/Q reﬂecting the quality of cogeneration.There exists a general consensus that cogeneration quality is given by the power-to-heat ratio.However,confusion is widespread on the precise deﬁnition of that ratio and on the methods to quantify the ratio. Fig.1provides the basic elements to resolve the confusion,with extended arguments and methods for assessing s values discussed in Section5.The northeast corner of Fig.1formats an electricity e heat(E,Q) diagram;the ordinate is the quantity of electricity(E)generated; the abscissa is the heat(Q)that may have been recovered from the point source heat exhaust.The words in italic in the previous sentence reveal that Q is an unsettled variable.Full recovery occurs in only a few power plants;in most power plants a(small)share of the point source heat exhaust is recovered for use.For the proper analysis of a CHP activity,the corresponding bliss point S needs identiﬁcation.A bliss point in a(E,Q)diagram is the point where after E is maximized,the sum E maxþQ max(Q max being the maximum recoverable quantity of heat)is also at its maximum. In positioning the bliss point S,abstraction is made of the actual use of the point source heat exhaust.When for example,the plant is equipped to only use at maximum30%of the point source heat exhaust of the power plant,S will be a virtual bliss point.The recognition and identiﬁcation of virtual bliss points,not directly observable,unveils the CHP mystery,what is crucial for the eval-uation of partial CHP activity.Once the bliss point S of a CHP activity is marked in the(E,Q) diagram of a power plant,the design power-to-heat ratio s is calculated as the slope of the vector O e S.Because s is a design attribute of the plant,s is a tombstone parameter,easy to reveal from the as built plans of the power plant with its various equip-ment and installations to manage and optimize the energyﬂows. When public policy meddles in the world of cogeneration,it should come up with regulations that support the maximization of s,the real quality parameter,decided during the design phase of the plant [9].This implies the maximization of electricity output,because the ﬁrst goal of expensive power plants remains the provision of high-quality power,not low-quality heat.Therefore heat recovery maximization is always secondary to power maximization(see: CHP paradox and bliss point deﬁnition).4.The merit of CHP and how to measure itPublic policy may support speciﬁcally CHP activity when demonstrating particular merit(Section4.1).In case of support, what outcomes of CHP activity are adopted as proper performance indicators(Section4.2)?4.1.Specifying CHP activity meritThe visions on the merit of cogeneration in the energy economy are not universal,leading to diverging and even opposite policies ranging from stimulating to actually destroying cogeneration’s role and development[9].The basic merit of CHP activity is the use of part or all of a thermal power plant’s point source heat exhaust, reducing heat rejection to the environment,and avoiding the use of other energy sources to provide the used heat.Ceteris paribus,this merit is sufﬁcient for ranking thermal power plants with heat re-covery facilities principally higher than its counterparts without such facilities.Adopting this merit is rooted in preferences for efﬁcient above wasteful energy use practices that cause greenhouse gas emissions[7].The argument is weakly strengthened by refer-ence to the reduction of local climate change effects caused by concentrated waste heat releases[14].Few countries have enacted or enforce a policy with a prefer-ence for cogeneration activities.An exception is Denmark where the1979Heat Supply Act has made this priority real.The important role of cogeneration in the Danish electricity system is evident[3].3This resembles shortcut language“heat”and“work”for the proper scientiﬁcterms“energy transferred as heat”and“energy transferred as work”,emphasized bye.g.Reynolds and Perkins[13].A.Verbruggen et al./Energy61(2013)575e5825774.2.Indicators of CHP performanceAlthough the merit of CHP is in recovering all or part of therejected point source heat,the recovered quantity of heat(Q used)isnot recommendable as indicator,because for investors and opera-tors rewarding Q used holds no stimulus to maximize the designpower-to-heat ratio.Amazingly,the2009adaptations to theemissions trading scheme[15]have changed the allocation rulesfor CHP generation,such that from2013onwards CHP plants willreceive only allowances for the used heat and no longer forcogenerated power.Westner and Madlener[16]assess the negativeimpact of this rule on future investment in large-scale CHP plants.Presumably,the reason of the EU adaptation is due to persistinglack of reliable and easily auditable methods for calculating thecogenerated power output.This article offers the approach to closethis gap.Including Q used as an additional indicator with accounting forthe quality of the recovered heat is proposed by experts in ther-modynamics[17].While heat at higher temperature corresponds toa higher availability(quality)of heatﬂows[13],rewarding this inCHP activities counteracts the incentives to reduce the appliedtemperatures of heat end-uses in buildings and processes.Thelower the useful end-use temperatures of heating applications canbe set,the smaller is b,the used heat for generated power substi-tution rate and the higher is s,the power-to-heat ratio of CHP ac-tivities embedded in steam turbines.The necessary and sufﬁcient CHP performance indicator is theaccurately assessed amount of cogenerated electricity E CHP.The E CHP variable is not directly observable when condensing and cogeneration activities are mixed,which is the dominant practicebecause few power plants face a sufﬁciently high heat demand torecover their full point source heat exhausts.E CHP is a part of themeasured E plant and has to be assessed.Generally accepted is therule E CHP¼“power-to-heat ratio”ÂQ used but lacking are deﬁni-tion and assessment of the proper power-to-heat ratio[7e9].Section5provides the methods for assessing the proper s for every CHP activity added on or embedded in various thermal powergeneration units.With measurements of the Q usedﬂows,the ac-curate E CHP¼s.Q used is calculated.The remainder(E plantÀE CHP)is condensing electricity.Rewarding E CHP includes incentives tomaximize E CHP,what also means investors and operators arestimulated to maximize the design quality(s)of the CHP activity and to maximize the quantities of recovered heat(Q used).This is the appropriate way to address the joint production paradox.5.Monitoring and measuring CHP activityThe temperatures of used heat demanded have a signiﬁcantimpact on some CHP activities,and on the choice of the hostingthermal power generation plants.Heat use is characterized by therequired temperature,needed for performing intended functions,such as space heating,washing,cooking,drying,eful heat isheat available at temperature sufﬁciently above ambient temper-ature to provide useful functions.Banding heat demand by tem-perature is recommended,for example:lowest(above ambienttemperature to50 C),low(50 e100 C),medium(100 e200 C), high(200 e400 C),very high(above400 C).Depending on the thermal power generation process,point heatsource exhausts deliver at different temperatures.Gas turbineoutlets range in the very high temperature band;at stacks of en-gines medium to high temperature heat is recoverable,and lowtemperature heat at mantle and oil coolers;the cold condensers ofsteam turbines offer massive heatﬂows in the lowest band.Only aminiscule part of the latter is useful for some nearby activities,suchas greenhouse or tropicalﬁsh culture.The height of the temperature of the point source heat exhausts is a crucial discre-tionary variable for classifying cogeneration activities in two groups:CHP activities without impact on the power output of the plant,and CHP activities with impact.The former refer to“added on”,and the latter to“embedded in”CHP activity.5.1.CHP activities without impact on the power output of the plantGas turbines and internal combustion engines deliver heatﬂows at sufﬁcient high temperature to match demand by a wide variety of applications.Gas turbine outlets are sufﬁciently hot to deliver pressurized steam for driving a steam turbine(the Combined Cycle Gas Turbine e CCGT(combined cycle gas turbine)plant).Directing their point source heat exhaust to used heat does not signiﬁcantly affect the electricity output of such plants.Fig.2a and b show representative shapes of their(E,Q)production possibility sets.In these cases,the coefﬁcient b is zero.When running the plant at full load,and an electricity output of E max is obtained,the discarded point source heat Q max¼FÀE maxÀL.The bliss point S is located at the coordinate(Q max,E max).When all that heat is used,the“bliss point”S is actually reached,maximizing the energy conversion efﬁciency(EþQ)/F of the plant.The design power-to-heat ratio s of this CHP activity is the slope of the vector O e S.In practical settings the demand for used heat at the plant may always be lower than the maximum recoverable heatﬂow Q max, and the capacity of the heat recovery facilities will be limited to the peak heat demand Q peak demand.The production possibility setisFig.2.(a)Cogeneration(E,Q)production possibility set of gas turbines and of internal combustion engines.(b)Truncated cogeneration(E,Q)production possibility set of gas turbines and of internal combustion engines.A.Verbruggen et al./Energy61(2013)575e582 578truncated.The bliss point becomes a virtual point,which results in it being overlooked.However,identi ﬁcation of the virtual bliss point is a necessity for a proper assessment of the design power-to-heat ratio s .5.2.CHP activities with impact on the power output of the plant Steam turbines are the main hosts of CHP activities.The tem-perature of their point source heat exhaust is scantly above the ambient temperature,hence not widely useful,although the ﬂows are massive due to the latent heat of condensing the steam rejected at the end of the turbine.Practical heat uses require higher than near ambient temperatures,which necessitates steam extraction at higher temperature and pressures.For optimizing steam cycles,small steam ﬂows are extracted from the turbines,and re-used in the cycles.Steam extracted for external heat demand before the end of a turbine where cold condensing conditions prevail,shortens the expansion path,i.e.reduces the work delivered and the power generated [13].A Mollier diagram offers a visible steam expansion path,which segment lengths re ﬂect the amount of po-wer extracted.Fig.3a shows how cogeneration is embedded in a steam cycle that is equipped with cold condensers (approaching near vacuum pressure conditions for the steam outlet)to function as an only cold condensing plant.For clarity of the argument here it is assumed all steam ﬂow can also be extracted either at a low or at a high backpressure (BP).To describe the production possibility sets of CHP activities,ﬁrst consider the full cold condensingstatus of the turbine:E cond electricity is generated,and the point heat source exhaust equals Q cond .Because Q cond has no economic value,one increases the temperature of the exhaust,viz.the backpressure to BP-low.This reduces the electric output to E BP-low ,and enlarges the point source heat ﬂow to Q BP-low ;this substitution of used heat for generated power is generally called “power loss ”(we prefer the term “used heat for generated power substitution ”),with b as common symbol.The value of b is evidently dependent on the backpressure experienced by the turbine ’s steam ﬂow [18].Fig.3a shows two levels of backpressure (low and high),with production possibility sets respectively triangle O e E cond e S BP-low ,and O e E cond e S BP-high (both truncated by minimum plant load constraints).Their used heat for generated power substitution rates differ,with as a corollary that their design power-to-heat ratios differ.Generalizing the argument reveals that a continuum of backpressures or hot condensing temperatures are feasible,each one de ﬁning another CHP activity embedded in the steam turbine power plant.Every CHP activity is characterized by its speci ﬁc b and s ,crossing in the speci ﬁc bliss point S BP .Fig.3a also shows the continuum of bliss points,as a segment of the line re ﬂecting the ﬁrst principle of thermodynamics F ÀL ¼E þQ,with the diffuse losses L stabilized at their minimum level [9].The ratio of latent to sensible heat in the total heat ﬂow decreases with higher back-pressure,as visually shown by more declining E cond e S BP lines (caused by higher b values).The incremental heat for power sub-stitution,by higher backpressure relative to a lower backpressure,is re ﬂected in the (equal to À1)slope of the set of bliss points.In practice,a steam turbine may have two major hot condensers for steam extraction.Assuming all steam can be extracted at all three condensers (one cold þtwo hot),the production possibility set of the steam plant is shown by area O e E cond e S BP-low e S BP-high e O .Generally,the heat extraction capacity at large steam plants will be limited by the demanded heat capacity of the end-uses (e.g.,the base load of a district heating system).This is shown in Fig.3b,derived from Fig.3a.The actual possibility set of the plant is the solid bordered pentagon,as a cut from the wider set dis-cussed in Fig.3a.When only viewing the smaller set without the virtual components underlying the set,it is dif ﬁcult to recognize the crucial parameters,such as the proper design power-to-heat ratio.Assessing E CHP is done ﬁrst by CHP activity:the heat recovery Q used at every hot condenser is measured and multiplied bytheFig.3.(a)Cogeneration (E ,Q )production possibility set of extraction-condensing steam turbines.(b)Truncated cogeneration (E ,Q )production possibility set of extraction-condensing steamturbines.Fig. 4.Cogeneration (E ,Q )production possibility set of pure backpressure steam turbines.A.Verbruggen et al./Energy 61(2013)575e 582579。

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538
18th International Conference on Computers and Industrial Engineering
different systems. Some techniques were introduced or invented for these purposes, such as technical innovation and revolution movement, mechanization and automation campaign in Anshan Iron and Steel Co., I-lao's operating method, Huang's warehouse-keeping method, Li's train-switching method, etc.[16]. These techniques contained a number of individual techniques in IE from nowadays viewpoint, though the term IE was not known at all at that time. An important event in this period is worth to be mentioned [4]. From 1965 to early 80's but interrupted for five years during the Culture Revolution, Prof. Hua Lo-geng, a world-wide famous mathematician, organized a team to popularize and apply Overall Planning Methods (OPM) and Optimum Seeking Methods (OSM). The former were similar to CPM, PERT and project management while the latter to Optimization. The team members visited thousands of industrial factories over 27 provinces, giving plain lectures to and making experiments with technicians and workers. Remarkable results in improving productivity and technology convinced vast numbers of people that scientific methods were useful and important to their own practical work (see [3] for example). IL Initiation Period (1978 - 1989) The Reform and Open Poficy promulgated in 1978 made great changes in industrial enterprises. In stead of political movements, economic development turned to be the focal point of the nation. Advanced technology and management techniques regained attention. In early 80's, the State Economy & Trade Commission issued an important document. It called for promoting 18 techniques aiming at the modernization of management. Among those techniques were, for instance, optimum seeking and optimization, overall planning, TQC, value engineering, card control, ABC analysis, etc., which could be classified as techniques in IE Many advanced management techniques, like modem IE, GT, CIMS, CAD/CAM/CAPP, TQC, physical distribution techniques .-" etc., were introduced into China by invited foreign experts or Chinese scholars who had studied abroad. Intensive training courses on special subjects of IE, like work study and materials handling, were organized. More and more IE applications were made in some large enterprises, In this period, more than one hundred of universities and colleges established, earlier or later, specialties or departments for Management Engineering (ME). Among the ME courses, many subjects are relative to IE: TQC, value engineering, MIS, human engineering, engineering economics, coordinated planning, system engineering, operations research, etc.. Many students who got well educated with these subjects became active researchers, trainers or practitioners in the IE field during the recent years. III. Developing Period (after 1990) A landmark decision was promulgated to call for transferring from the planned economy to Socialist Market Economy. Many enterprisers and managers are getting conscious of the importance of modern management techniques like IE that are efficient for improving productivity and profitability hence are powerful for market competition. Initiated by some foresighted experts, like Mr. Renkang Wang and Mr. Shuwu Zhang, the Industrial Engineering Institute attached to the Chinese Mechanical Engineermg Society (IEI-CMES) was established in !990, which was the first national academic IE organization in China. smee then, Modern IE has been energetically and organizationally promoted in industrial as well as academic circles, and gets rapid development in many aspects which will be introduced in next section.
Computersind.gaSa8, VoL31,No.3/4,pp.537- 542,1996
Pergamon S0360-8352(96)00059.9 o360-8352~6 Sls.0o + 0.00
~ g h t © 1995ChinMachmPr~ PublishedbyElsevierSeie~oe Ltd.Pt~edin GreatBritain
engineers and IE courses were seldom given in higher education until late 70's. In receat years, IE has made considerable progress. Emerging market economy provides an arena for industrial engineers to fully display their talents. IE certainly will get rapidly developed in the near future. Keywords: Industrial Engineering, Work Study, Facility Planning and
I k s ~ ~mgment ~
Optimization.
பைடு நூலகம்
1. The Course of IE Development in China

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