EH_skinarchitecture_mh

Skin Architecture:Michele HanThe SkinThe first line of defense, skin protects against infec-tion, abrasion, and water loss. It contains nerveendings vital for sensation, such as touch, pain, heat, and cold. It produces vitamin D on exposure to UV rays in sunlight, monitors the body’s salt balance, and regulates body temperature. Skin is the body’s largest organ.It is a boundary, separating man from environment. Adapting and responding, it maintains a constant equilibrium; it creates homeostasis.The term homeostasis is referred to by Flood and Carson (1993) as a process by which a system preserves its existence through the maintenance of its dynamic equilibrium.dermal papillaeillustrations from THE PEOPLE’S COMMON SENSE MEDICAL ADVISER IN PLAIN ENGLISH, FIFTY-FOURTH EDITION. R.V. Pierce, MD, 1895 </files/18467/18467-h/advise.html>Thermoregulation Blood is shunted around the body to create a different heat distribution depending on the external climate, internal heat genera-tion and heat loss mechanisms.Despite the extreme variance of environ-mental temperatures, the body restricts its core to a very narrow thermal range, the extremes of either of which is death.The skin provides the interface by which the body controls this internal thermal environment. Embedded with sensors and equipped with an array of mechanistic re-sponses, the skin acts as a surface through which to radiate or absorb heat.RISE IN CORE BODY TEMPReceptors in hypothalamus detect increase in core temp/temp of bloodVASODILATION of arteriolesSHUNT VESSELS CONSTRICT increased blood flow to skin surface; heat loss by RADIATIONHeat loss by EVAPORATION of sweat; sweating leads to a lower skin tempVOLUNTARY ACTION - remove clothing; seek cooler area; or cold drink86939698101011February, South Pole Station -403268July, Yuma Arizona 86104July , Death Valley 122 140Hot desert sand 176Very hot sauna212Environmental Temperatures°F°FHuman Co Temperatu86 Decreased shivering, erratic movements, incoherent93 Violent shivering; speech and thought impaired 96 Intense shivering and Impaired coordination98 Normal Range100 Extreme physical exercise and fever107 Heat stroke, brain damage111Upper limit for survival, impaired thermal regulation403268860422407612Thermal Ranges, adapted from “The Skin’s Role in Human Ther-moregulation and Comfort” (Edward A. Arens_ H. Zhang).DROP IN CORE BODY TEMPReceptors in hypothalamus detect increase in core temp/temp of blood.VASOCONSTRICTION of capillaries in the skin narrow SHUNT VESSELS DILATE Less blood flows to skin surface = less heat is lost by RADIATION Hair raising - greater insulationShivering - rapid contraction and relaxation of muscles produces heat by RESPIRATIONAdrenaline INCREASES METABOLIC RATE of cells VOLUNTARY ACTION - put on clothes; seek warmer areas or warm drink30’10° F 0° F20° F 30° F 40° F 50° F 60° F 70° F 80° F 90° F 100° F110° FThe problemUnfortunately, the NYC subway is not as efficient in its thermoregulation.In the summer, when an underground tunnel would seem a refuge, temperatures commonly register 110 degrees on popular platforms – the human body, subjected to prolonged exposure to such heat risks heatstroke and brain damage.“Sometimes it’s so hot on the platform that I can’t breathe. I would think the MTA would want to do something about the temperature on the platforms so they don’t have people passin’ out all over the place.” Victoria Jeter, Second Ave Sagas Blogger < http:///2007/07/11/key-temperature-question-conspicuously-absent-from-summer-subway-reports-cards/#comment-905>“The Metropolitan Transportation Authority has tried to calculate the sources of this seasonal discomfort. It found that brakes produced 60 percent of the heat, air-conditioning provided 20 percent and accelera-tion 13 percent -- a total of 93 percent of the heat from the trains. Humans and electrical equipment (they are lumped into one category by the M.T.A. for the purposes of assessing heat, it seems) added only 7 percent to the mix.” “The City Life; Summer’s InfernalSubway, ELEANOR RANDOLPH. August 9, 1998. NEW YORK TIMES </gst/fullpage.html?res=9C04E4D6103BF93AA3575BC0A96E958260>.Air-conditioning - meant to temper the environment - only adds to the discomfort, producing 20% of platform heat gain.The thermal mass of the ground acts as an insula-tor, preventing the dissipation of accumulated heat.Ventilation draws air in from the street, and vents it back; hot air produced within the subway tunnels is vented out onto the streets and sidewalks. Dur-ing the winter this might seem like a good thing, but during the summers it makes the city heat even more unbearable.The proposalThis project looks at an alternate means of ventila-tion, using the regulatory properties of human skin as precedent to create a homeostatic environment within the new subway extension.OFF-ISLAND TRANSFER STATIONSESTIMATED HEAT GAIN2ND AVE TUNNEL EXTENSIONThe site:providing a new line of running N-S.The modelA performative model was designed to explore ameans of taping these pressure differentials.A series of clear chambers equipped with permeable deformable membranes that animate the creation of pressure differentials and the direction of air flow.A 2” pvc pipe was used to simulate a subway tunnel, with a 2” plastic plunger pump to simulate the pass-ing train.Check valves direct and control the inlet and outlet of air. A check valve allows fluid (liquid or gas) to flow through it in only one direction. When the pump is set in motion, a high pressure compression wave pushes air out of the outlet valves in front of the plunger, while a low pressure wake behind the plunger draws air in through inlet valves.DIRECTIONAs the pump passes, depending on the direction of the valve, air is pushed either in or out of the cham-bers. With each pass, the membrane separating the chambers deflects towards the side of lower pres-sure. When the pump ceases, air is diffused through the membranes. The result is a choreographed diffu-sion of air from high to low pressure, animated by the slowly deforming shapes of the membranes.The systemApplying this logic to the site, a network of check valves embedded throughout the Second Avenue tun-nel is used to channel air through a vascular system that uses the thermal mass of the earth to create a temperate subway environment.As the train passes, tunnel inlet valves draw surfaceair in from the street level. The air is passed through filters to sift out particulates, and long pipes that use the constant temperature of the earth (approximately 50 degrees Fahrenheit) to temper the air.This cleaned and tempered air is drawn through the stations into the tunnel, and expelled by outlet valves onto the sidewalks.heatNO 14th Street2nd Aveheat sensitive inlet valve supply pipeInlet ValvesONOFFONAir Pressure, bladderintakeAB!4th Street Station SectionsReferencesSkinillustrations from THE PEOPLE’S COMMON SENSE MEDICALADVISER IN PLAIN ENGLISH, FIFTY-FOURTH EDITION. R.V. Pierce,MD, 1895 </files/18467/18467-h/advise.html>“Modelling and Simplification of a Human Thermoregulation Modelfor thermal comfort regulation in a car interior” Lakhdar Benasser,Genevieve Dauphin-Tanguy, & Jean-Christophe kat. Proceedings ofthe 1999 EEUASME International Conference on Advanced Intel-ligent Mechatronics September 19-23, 1999 Atlanta, USA.“The Skin’s Role in Human Thermoregulation and Comfort” (Ed-ward A. Arens_ H. Zhang).“Skin Blood Flow in Adult Human Thermoregulation: How It Works,When It Does Not, and Why” Nisha Charkoudian, PHD. Mayo ClinicProceedings. 2003;78:603-612“Thermal sensation and Thermoregulation” Professor Alan Hedge,Cornell University, January 2007Histologic Diagnosis of Inflammatory Skin Diseases, A. BernardAckerman, Almut Böer, Bruce Bennin, and Geoffrey J. Gottlieb.2002–2006 Ardor Scribendi, Ltd. </public/freesamples/inflam001.html>Subway“Design of a modern subway ventilation system.” Tunnels & Tun-neling International NOVEMBER 2004. (pg 48-50)MTA Capital Construction - Second Avenue Subway Planning Study.</capconstr/sas/sas_documents.htm>“Fainting dieters a top cause of NYC subway delays”PostedBy Gina Pellrine, 9 January 2007. <http://www.thefinalsprint.com/2007/01/fainting-dieters-a-top-cause-of-nyc-subway-de-lays/>Arup Capability Statement, Consultancy Services for Ventila-tion, Aerodynamics, Fire Smoke Control and MEP Systems inTunnels.</industrial>“Analysis of Flow and Transport in Subway Systems”, W. E. Dunn,*B. R. Green U.S. Army, DOE ANL 980072401“Manhattan East Side Transit Alternatives (MESA)/Second AvenueSubway Summary Report”, MTA New York City Transit, VollmerAssociates, LLP SYSTRA Consulting, Inc. Allee King Rosen & Flem-ing, Inc. October 2001“The City Life; Summer's Infernal Subway, ELEANOR RANDOLPH.August 9, 1998. NEW YORK TIMES </gst/fullpage.html?res=9C04E4D6103BF93AA3575BC0A96E958260>.Skin Architecture20Michele Han21。