Shelf-Life Evaluation of Lead-Free Component Finishes

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Lead Free HASL- A Viable Option

PRODUCT PROFILEELECTROLOY in partnership with FCT Asia Pte Limitedin ManufacturingNihon Superior Lead Free Solder BarSN100CLProduct Name Product CodeLEAD FREE BAR SN100CLLEAD FREE BAR SN100CLe(TOP UP ALLOY)The information and statements herein are believed to be reliable but are not to be construed as a warranty or representation for which we assure legal responsibility. Users should undertake sufficient verification and testing to determine the suitability for their own particular purpose of any information or products referred to herein. No warranty of fitness for a particular purpose is made. Properties are typical and not to be used as specifications.DOC CATEGORY: 3 PF – SN100CL – 09022009 – REV.B – Page 1 of 6DOC CATEGORY: 3PF – SN100CL – 09022009 – REV.B – Page 2 of 6PRODUCT INFORMATIONElectroloy has entered into an agreement with FCT Asia Pte Limited to manufacture SN100CL solder alloy with patent license from Nihon Superior.SN100CL is a lead-free solder containing tin, copper, nickel and other proprietary elements that make this alloy suitable for Hot Air Solder Leveling (HASL) process. All of the final finishes available in the market today have both their merits and demerits. Many in the PCB industry are concerned about switching from HASL to a less forgiving final finish as they transit to the up and coming lead free era.The SN100CL alloy use in the HASL process should arise these concerns.The patented addition of nickel to the tin-copper eutectic offers the following advantages: o Low cost lead free alloyo Low dross than other lead free alloyo Excellent fluidity with very uniform and flat surfaces o Bridge free coating and fine pitch circuitry o Low copper erosion o Good shelf lifeo Minimal attack on stainless steel pot o Close to eutectic temperatureo Easy to manage alloy compositiono Compatible with both 63/37 and lead free final assemblyEXCELLENT FLUIDITYFig. 2 Good penetration small diameters holes & uniform coating thickness and smooth bright finishFig. 1 Excellent fluidity of SN100CL ensures no bridges onfine pitch track patternDOC CATEGORY: 3PF – SN100CL – 09022009 – REV.B – Page 3 of 6LOW COPPER EROSIONo SN100CL does not corrode copper onthrough-hole walls and shoulders quickly. o The quality of copper coatings and tracks are maintained.o Less maintenance is required to maintaincomposition of solder bath.o Presence of nickel retards the diffusion ofcopper and slows down corrosion.STABLE INTERMETALLIC FORMATIONo Aging experiments at 1200C for 0, 192 and 768 hours shows that the intermetallic layer grows relativelyslowly than that Sn-3.0Ag-0.5Cu.o The thickness of the Intermetallic layer of SN100CL remains effectively constant even after 768 hours ofageing at 1200C.o Nickel in the Intermetallic layer slows down diffusion of copper atoms into this layer and improves thestability of this layer.o Stability of the Intermetallic layer enables good solderability.Fig.3 Copper thickness after immersion in a solder bath at 2750C for 3 seconds (a) and 8 seconds (b). Copper thickness decreases only by 0.5 μm to 2.0 μm after immersion for 8 seconds.Fig. 4 Stability of the Intermetallic layer in SN100CL coating (a) (b)DOC CATEGORY: 3PF – SN100CL – 09022009 – REV.B – Page 4 of 6SOLDERABILITYo Solderability is lost when the Intermetallic layer grows through the surface.o The stability of the Intermetallic layer in the presence of nickel ensures lasting solderability. o The solderability can survive several cycles of adhesive curing or paste reflow.o A properly applied SN100CL coating has a solderability shelf life of about one year.oSolderabilty of SN100CL in comparison with other board finishes was tested as a function of thermal aging with reflow cycles and 4 hours 155ºC aging.o Solderability decreases expectedly with multiple reflow and heat aging steps. It can be seen from theresult, however, that SN100CL is a reliable surface finish and performs well.THICKNESS CRITERIAo Solder layer thickness in HASL are affected not only by the air pressure, pad size and board orientation,but also by the type of solder used.o A thickness of pure SN100CL of 0.9 μm is required for good solderability.o Experiments to compare the thickness of HASL layer using SN100CL and a leaded solder show thatSN100CL thickness of 1.5 to 2.5 μm is easily achievable.Fig. 5 Solderability of SN100CL coatingFig. 6 Thickness obtainable in HASL SN100CL coatingDOC CATEGORY: 3PF – SN100CL – 09022009 – REV.B – Page 5 of 6CHEMICAL COMPOSITION OF ALLOYThe composition of SN100CL & SN100CLe lead free bar is strictly controlled to the following specification: -ELEMENT SN100CL SPECIFICATION SN100CLe SPECIFICATION J-STD-006B (TOP UP ALLOY ) Amendment 1TINREMAINDERREMAINDER REMAINDERLEAD < 0.050 %< 0.050 %MAX.0.070 %ALUMINIUM < 0.002 % < 0.002 % MAX.0.005 %ANTIMONY< 0.050 %< 0.050 % MAX.0.200 %ARSENIC < 0.030 % < 0.030 % MAX.0.030 %BISMUTH < 0.030 %< 0.030 % MAX.0.100 %COPPER 0.65 ± 0.05 % < 0.1 % -IRON < 0.020 % < 0.020 % MAX.0.020 %ZINC < 0.002 % < 0.002 % MAX.0.003 %CADMIUM < 0.002 %< 0.002 % MAX.0.002 %SILVER < 0.050 % < 0.050 %MAX.0.100 %NICKEL 0.05 ± 0.01 % 0.05 ± 0.01 %-INDIUM --MAX.0.100 %GOLD--MAX.0.050 %PRODUCT APPLICATIONThe SN100CL lead free alloy can be used in both vertical and horizontal HASL machines.As the SN100CL solder bath is used, copper tends to dissolve into the solder from the bare board. If the copper content of the solder bath exceeds 0.85%, there is likely to be an increase in the incidence of bridges, and overall graininess.In order to maintain the proper copper level in the bath, Electroloy recommends the SN100CLe as the top-up alloy.The recommended operating window for copper is between 0.5 and 0.85%. Verification of copper content is easy with free Solder Pot Analysis offered by Electroloy. The statistical analysis of your solder pot will help you monitor the copper level over time & make critical decision to achieve good production yield with the SN100CL bars.Recommended Operating ParametersSetting/ ProcesstypeDip TimeConveyor SpeedContact TimeAir Knife TempPot TempVertical 1.0s – 3.0sNA NA 260-265°C 260-270°C Horizontal NA10-15m/min. 0.5s – 1.0s260-265°C260-270°CDOC CATEGORY: 3PF – SN100CL – 09022009 – REV.B – Page 6 of 6PHYSICAL APPEARANCEThe SN100CL lead free bars come in triangle casted and extruded types. The SN100CL exhibit a shiny appearance & uniform silver-grey in color. The brand & alloy code is embossed onto the surface of each bar. Each bar is approximately 700 – 900 grams in weight. The physical dimension is about 330mm x equal side of 24mm.PACKAGINGThe SN100CL lead free bars are pack into “White “carton boxes of 20kg each. Each box contains the following traceable information:1. The Supplier2. Grade3. Product Code / Type4. Lot Number5. Weight per BoxDELIVERYEach shipment shall be accompanied with a Certificate of Analysis for each lot, which indicates the impurity level of each element according to SN100CL Specification.STORAGE AND SHELF LIFEThe SN100CL lead free bars have no limited shelf life when handled properly. Storage must be in a dry & non-corrosive environment.To minimize the bars from further oxidation, ensure that the packaging is not damaged.The solder surface may lose its shine & appear a dull shade of light yellow. This is a surface phenomenon & is not detrimental to product functionality & performance.HEALTH AND SAFETYRefer to the MSDS for guidance on safety and health issues.Fig. 7 SN100CL solder bars。

全程低温陈列柜销售对带鱼品质变化的影响_高志立_谢晶_杨胜平_施建兵_熊青

DOI：CNKI:11-1759/TS.20130625.1052.014 网络出版时间：2013-06-25 10:52网络出版地址：/kcms/detail/11.1759.TS.20130625.1052.014.html全程低温陈列柜销售对带鱼品质变化的影响高志立，谢晶*，杨胜平，施建兵，熊青（上海海洋大学食品学院/上海水产品加工及贮藏工程技术研究中心，上海201306）摘要：针对目前我国市场上带鱼销售过程中出现的货架期短暂、操作困难等问题，本文提出了全程低温陈列柜的销售方式，并与模拟的农贸市场销售和超市销售条件下带鱼的品质变化进行比较。

通过对这三种不同销售过程中带鱼的感官、微生物指标、pH值、挥发性盐基氮（TVB-N）、三甲胺（TMA-N）、硫代巴比妥酸（TBA）和K值等指标进行测定，结果表明：农贸市场销售和超市销售的带鱼货架期分别为3d和4d，而全程低温陈列柜销售能更好的延长带鱼的货架期，可保藏带鱼到第6d。

与农贸市场和超市销售的带鱼相比，全程低温陈列柜销售的带鱼的货架期延长了2~3d，值得推广。

关键词：带鱼销售；模拟；陈列柜；农贸市场；超市；货架期Quality changes of Trichiurus haumela in the low temperaturedisplay cabinet sales processGAO Zhi-li, XIE Jing, YANG Sheng-ping, SHI Jian-bing, XIONG QingAbstract: In this paper, low temperature display cabinet sales mode was proposed to solve the problems appearedin the sales process of Trichiurus haumela.Quality changes in the low temperature display cabinet sales weremeasured and compared with farmer's market sales and supermarket sales. The sensory evaluation, microbial andphysicochemical indicators including pH value, total volatile basic nitrogen (TVB-N), trimethylamine (TMA-N),thiobarbituric acid (TBA), K value of T richiurus haumela were analyzed in these selling processes. The resultsshowed that the shelf-life of farmer's market and supermarket sales mode were 3d and 4d, respectively. Theshelf-life of low temperature display cabinet sales mode was 6d, which extended the shelf-life with 2 ~ 3 d andshould be promoted.Key words:Trichiurus haumela sales; simulate; display cabinet;farmer's market; supermarket; shelf-life中图分类号：TS205.7 文献标志码：A带鱼（Trichiurus haumela）是我国最著名的大宗物流海水鱼[1]，是我国最重要的经济鱼类之一，其中东海带鱼尤为出名。

退役铅酸蓄电池铅膏回收策略及研究进展

第15卷第2期2024年4月有色金属科学与工程Nonferrous Metals Science and EngineeringVol.15，No.2Apr. 2024退役铅酸蓄电池铅膏回收策略及研究进展裴启飞1，卢文鹏1，邓蓉蓉2，高明远2，张启波*2（1.云南驰宏锌锗股份有限公司，云南曲靖655011； 2.昆明理工大学冶金与能源工程学院，昆明 650093）摘要：推动再生铅产业的高质量发展，是铅资源实现生产-消费-再生良性循环的重要保障，缓解铅资源枯竭的同时，有效降低铅的生产成本和改善环境污染，对促进铅工业可持续发展具有重要的战略意义。

本文概述了近年来铅酸蓄电池铅膏回收的最新研究进展，基于铅酸蓄电池的资源特点和再生产品的经济效益，详细总结了以金属铅、氧化铅、硫化铅及功能性铅基材料为目标的回收工艺技术，重点分析了不同铅产品回收方法的优缺点及需注意的关键环节。

结合铅产业链的下游应用，介绍了废铅酸蓄电池再生产品在电池及传感器等领域的应用。

最后从实际应用角度出发，展望了未来废铅酸蓄电池铅膏回收及再生铅产品的发展方向。

关键词：铅酸蓄电池；回收；金属铅；氧化铅；硫化铅；含铅电池材料中图分类号：TF812 文献标志码：ARecent advances in recovery strategies of lead paste fromretired lead-acid batteriesPEI Qifei 1, LU Wenpeng 1, DENG Rongrong 2, GAO Mingyuan 2, ZHANG Qibo *2（1. Yunnan Chihong Zn & Ge Co.， Ltd.， Qujing 655011， Yunnan ， China ；2. Faculty of Metallurgical and Energy Engineering ， KunmingUniversity of Science and Technology ， Kunming 650093， China ）Abstract: Promoting the high-quality development of the recycled lead industry is not only an essential guarantee for lead resources to enter a virtuous cycle of manufacture-expense-regeneration but also a vital strategy to alleviate the depletion of lead resources, effectively reduce production costs, and alleviate environmental pollution, which is of a great strategic significance for the sustainable development of the lead industry. This paper reviewed the latest research progress on lead recovery from spent lead acid battery paste. Based on the resource characteristics of lead-acid batteries and the economic benefits of recycled products, the new recycling technologies targeting metal lead, lead oxide, lead sulfide, and functional lead-based materials were summarized in detail. It also introduced the advantages, disadvantages, and critical links of recovery methods for different lead products, and then presented the applications of recycled products in the field of batteries and sensors, combining the downstream applications of the lead industry chain. From actual application perspectives, the future development direction of recovery and regeneration lead products from the waste lead paste has finally been prospected.Keywords: lead-acid battery ； recycling ； lead metal ； lead oxide ； lead sulfide ； lead-containing battery materials收稿日期：2023-04-18；修回日期：2023-06-13基金项目：国家自然科学基金资助项目（21962008）通信作者：张启波（1984—　），博士，教授，博士生导师，主要从事电化学冶金方向研究。

新视野大学英语第三版Book1UNIT2带课后答案分析解析

Unit 2 Section A
A child’s clutter awaits an adult’s return
Loving parents, loving children
There is no friendship, no love, like that of the parent for the child.
— Henry Ward Beecher
While we try to teach our children all about life, our children teach us what life is all about.
— Angela Schwindt
Section A
Objectives
desk. 2) get rid of sth. 丢弃；人们处理掉垃圾，有时候丢在树林，污染了环境。 People get rid of trash and dump them in the woods,
which caused serious pollution .
Word formation NOTE 名词后缀:- ment v.+ment表示1) 结果，产物(如movement)；2）方法
Usage NOTE await, wait 区别
await是及物动词，后面直接跟宾语，用法比较正式； wait一般用作不及物动词，常与for，till，until等词连用。
b) 一般来说，await的宾语大多为抽象名词，如decision， reply， arrival，return等；
and subjects, books, clothes, …
Mother’s response
pack … into a box, stack …onto a single shelf, separate … into two piles, turn … into …

Lead free与Halogen free

The comparison of Tin / Lead and Lead / FreeW.S270 ℃----------------------Reflow:225 ℃183℃----------------------------------Tin/Lead Soldering Lead -Free Soldering有鉛與無鉛之優劣比較¾SAC305液化熔點高出34 ℃，操作時間延長20秒，熱量大增¾Sn63之reflow峰溫平均225 ℃，波焊峰溫平均250 ℃；SAC305reflow reflow峰溫245 ℃，僅提高20 ℃，波焊峰溫平均270 ℃。

¾無鉛wetting time : 2秒，Sn63 : 0.6秒¾SnCu熔點227 ℃，會對板材與綠漆造成軟化與傷害，易氧化、短路或空銲。

¾無鉛強熱快速溶銅之污染，每增加0.1% wt則熔點上昇3℃，流動性不足，粘度增加，焊錫性變差¾無鉛表面張力大，散錫性及上錫性差¾無鉛插腳之波焊可能改錫膏填孔再插腳熔焊¾無鉛操作溫度距熔點之落差變小，造成液錫的移動性及流動性變慢表面處理之性質比較項目/ 種類OSP I-Ag I-Sn ENIG1. 平坦度良好良好良好良好2. Shelf Life 6月 6 月6月1年3. 3次250 ℃熔焊很差很差尚好佳60sec後之焊錫性4. 是否需N2環境需要需要可免用5. 可重工性容易困難容易困難6. S/M匹配性無無必需必需7.反應時間60秒60秒12分鐘10~25分鐘8.反應溫度45℃50℃70℃85℃註: HASL逐漸淘汰，波焊逐漸減少，錫膏主流Sn /Ag /CuPCB Surface Finished ComparisonPCB Surface FinishPros ConsPb-free HASL Good solderability Lack of consistency and flatness OSP Low cost ；flatness Solder ability degradation@ elevatedtemperatures for multiple heat cycles ENIG Excellent solderability；flatness；Al-wireBondability；low contact resistance“Black pad” concernElectrolytic Ni/Au Excellent solderability；flatness；Wirebondability；low contact resistanceHigh cost；Au embrittlement if toothickI-Ag Good solderability；flatness；Al - wirebondability；low contact resistanceTarnish (cosmetic)I-Sn Flatness；Excellent solderability withfresh board Solderability degradation @ elevated temperatures for multiple heat cycles表面處理研討化金1.IMC:Ni3Sn4，金愈厚發生金脆，純鎳易鈍化，薄金保護免生鏽及鈍化‧2.鎳液老化易生黑墊(Black pad)，因金水活性太猛，氧化鎳未全數水解前即被金披覆，鎳與金界面出現很多疏孔，Ni表面鈍化、氧化不易和Sn 結合，造成SMT後之元件脫落，分析異常之磷含量10%↑。

Shelf Life Testing Procedures and Prediction Methods for Frozen Foods

Shelf Life Testing:Procedures and Prediction Methods for FrozenFoodsBin FuKellogg's Battle Creek MITheodore P. LabuzaDept. of Food Science & Nutrition, University of Minnesota1334 Eckles Ave., St. Paul, MN 5510819.1IntroductionThe shelf life of a food can be defined as the time period within which the food is safe to consume and/or has an acceptable quality to consumers. Just like any other food, frozen foods deteriorate during storage by different modes or mechanisms, as summarized in Table 1. Microbes usually are not a problem since they cannot grow at freezing temperatures unless subjected to extensive temperature abuse above the freezing point. Enzymes are a big concern for frozen foods, which can cause flavor change (lipoxygenase) in non-blanched fruits and vegetables and accelerated deterioration reactions in meat and poultry (enzymes released from disrupted membranes during precooking). Cell damage or protein and starch interactions during freezing cause drip and mushiness upon thawing. Discoloration could occur by non-enzymatic browning, bleaching, and freezer burn. Vitamin C loss is often a major concern for frozen vegetables. Physical changes, such as package ice formation, moisture loss, emulsion destabilization, recrystallization of sugars and ice of frozen desserts are often accelerated by fluctuating temperatures.For any specific frozen product, which mode determines its shelf life, depends on the product characteristics (raw materials, ingredients, formulation), pre-freezing treatment, freezing process, packaging film and processes, and of course storage conditions. All of the quality deterioration and potential hazards are usually exaggerated or complicated by a fluctuating time-temperature environment (e.g. freeze/thaw cycle) during storage. On the other hand, the shelf life of a frozen food can be extended through ingredient selection, process modification and change of package or storage conditions, as discussed in Section 3 of this book.This chapter will focus on shelf life testing of frozen foods for product development and market practices. Shelf life testing consists basically of selecting the quality characteristics which deteriorate most rapidly in time and the mathematical modeling of the change. Table 19.1 can be used as a reference for the selection of quality characteristics, which depends on the specific product and usually requires professional judgment. Mathematical modeling of quality deterioration will be discussed next.Table 19.1 Deterioration modes of frozen foodsFrozen Foods Deterioration ModesFrozen meats, poultry and seafood RancidityToughening (protein denaturation)DiscolorationDesiccation (freezer burn)Frozen fruits and vegetables Loss of nutrients (vitamins)Loss of texture (temperature abuse)Loss of flavor (lipoxygenase, peroxidase)Loss of tissue moisture (forming package ice)DiscolorationFrozen concentrated juices Loss of nutrients (vitamins)Loss of flavorLoss of cloudinessDiscolorationYeast growth (upon temperature abuse)Frozen dairy products(ice cream, yogurt, etc.)Iciness (recrystallization of ice crystals) Sandiness (lactose crystallization) Loss of flavorDisruption of emulsion systemFrozen convenience foods Rancidity in meat portionsWeeping and curdling of saucesLoss of flavorDiscolorationPackage iceFrozen bakery products (raw dough, bread, croissants)Burst can (upon temperature abuse) (dough) Loss of fermentation capability (dough) Staling (becoming leathery)Loss of fresh aroma19.2Modeling of quality deterioration19.2.1 Basic equationA frozen food starts to degrade once it is produced (Figure 19.1). The rate and the degree of degradation depends on both the composition and the environmental conditions during storage and distribution. In general, the loss of food quality or shelf life is evaluated by measuring a characteristic quality index, "A". The change of quality index A with time (dA/dt) can usually be represented by the following kinetic equation:- dA/dt = k A n(19.1)where k is called a rate constant depending on temperature, product and packaging characteristics; n is a power factor called reaction order which defines whether the rateof change is dependent on the amount of A present. If environmental factors are held constant, n also determines the shape of deterioration curve.AAtFigure 19.1 Quality deterioration curves: a) linear; b) exponential;c) hyperbolic; d) quadratic; e) complex.19.2.2 Zero and first order kineticsEquation 19.1 can also be written as:f(A) = k t(19.2)where f(A) is the quality function, k and t are the same as above. The form of f(A) depends on the value of n. When n is equal to zero it is called zero order reaction kinetics, which implies that the rate of loss of quality is constant under constant environmental conditions (curve (a) in Fig. 19.1). If n is equal to one it is called first order reaction kinetics, which results in an exponential decrease in rate of loss as quality decreases (curve (b) in Fig. 19.1, which becomes a straight line if plotted on a semi-log plot). These quality functions can be expressed as follows:f(A) = A o - A = k z t zero order(19.3a)f(A) = ln A o - ln A = k f t first order(19.3b)where A o is the initial quality value. If A e corresponds to the quality value at the end of shelf life, th e shelf life (θ) of the food is inversely proportional to the rate constant:θ = (A o - A e) / k z zero order(19.4a)θ = ln (A o/A e) / k f first order(19.4b)It should be noted that most chemical reactions leading to quality loss in frozen food systems are much more complex. However, the reaction kinetics can be simplified into either pseudo-zero order or pseudo-first order kinetics. In the case of complex reaction kinetics with respect to reactants, an intermediate or a final product (e.g. peroxides or hexanal in lipid oxidation ) could be used as a quality index. There are few cases where neither zero nor first order kinetics apply. Curve (c) in Fig. 19.1 shows the degradation curve for a 2nd order reaction (with single reactant), which also shows a straight on a semi-log paper. A fractional order should be used to describe the curve (d) in Fig. 19.1.Sometimes, there is an induction period or lag time before the quality deterioration begins (e.g. browning pigment formation in the Maillard reaction or a microbial growth lag phase, as shown in curve (e) in Fig. 19.1. The length of the lag depends on many factors, but temperature is a predominant factor. Given this, modeling of both the induction or lag period and deterioration phase are necessary for accurate prediction of quality loss or shelf life remaining. An example of such work has been demonstrated by Fu et al. (1991) for the growth of bacteria in milk.In certain circumstances (e.g. A represents a sensory hedonic score), a non-kinetic approach, e.g. a statistical data fitting technique can also be used to describe the deterioration curves. Varsanyi and Somogyi (1983) found that the change in quality characteristics as a function of time could be approximately described with linear, quadratic and hyperbolic functions and that storage temperature and packing conditions affected the shape of the deterioration curves. However, the parameters determined by data fitting are difficult to use for prediction under variable storage conditions except for the linear curve.19.2.3 Temperature dependence of deterioration rate19.2.3.1 Arrhenius kineticsOnce a frozen product is made and packaged and starts its journey from the manufacturer's plant to warehouse, distribution center, retail store and finallyconsumer's freezer, the rate of quality loss is primarily temperature dependent(Zaritzky, 1982). The Arrhenius relationship is often used to describe the temperature dependence of deterioration rate where for either zero or first order:k = k o exp (-E a /RT)(19.5a)or ln k = ln k o - E a /(RT)(19.5b)where k o is a pre-exponential factor; E a is an activation energy in cal/mol; R is the gas constant in cal/mol K and equal to 1.986; T is an absolute temperature in K (273 + °C).Thus, a plot of the rate constant on semi-log paper as a function of reciprocal absolute temperature (1/T) gives a straight line as shown as Fig. 19.2. The activation energy is determined from the slope of the line (divided by the gas constant R). A steeper slope means the reaction is more temperature sensitive, i.e., a small change in T produces are large change in rate.Figure 19.2 Arrhenius plotln k1/TThus, by studying a deterioration process and measuring the rate of loss at two or three temperatures (higher than storage temperature), one could then extrapolate on an Arrhenius plot with a straight line to predict the deterioration rate at the desired storage temperature. This is the basis for accelerated shelf life testing (ASLT), which will be discussed later. One should note however that in some cases a straight line will not ensue for a variety of reasons, especially if a phase change occurs (Labuzaand Riboh, 1982). Thus for frozen foods, extrapolation from temperatures above 0∞C are meaningless for shelf life prediction.19.2.3.2 WLF kineticsBesides the Arrhenius equation, another popular equation at least in the more recent food literature, is the Williams Landau Ferry (WLF) model (Williams et al., 1955). Its original form was based on the variation of the viscosity in the temperature range above T g as addressed in Chapter 3. When the rate constant at T g' is substituted for T g (T g' is the T g of a maximally freeze-concentrated system), the WLF model can be written as follows:log (k T/k g) = C1(T-T g')/[(C2+(T-T g')] (19.6a) or[log (k T/k g)]-1 = (C2/C1)/(T-T g') + 1/C1(19.6b)where C1 and C2 are constants. Thus a plot of [log (k T/k g)]-1 vs. (T-T g)-1 will be a straight line with the slope equal to C2/C1 and the intercept equal to 1/C1. As can be seen this is a two parameter temperature dependent model as is the Arrhenius equation.Frozen foods stored below T g' are stable to ice recrystallization and other physical changes. Levine and Slade (1988) postulated that stability is related to the temperature difference between storage temperature and T g'. This cryostabilization of foods assumes stability below T g' and rapid decrease of stability above T g' according to the WLF relationship, exhibiting an increase in reaction rate, much higher than expected from the Arrhenius kinetics. However, this may not be true since the rate of chemical reactions can be expected to be influenced by temperature increase in a complex way: (i) an increase of the rate constant, resulting from both the viscosity decrease and the increased molecular mobility (Fennema 1996); (ii) a decrease of the reaction rate as a consequence of the increasing dilution of the reactants Roos et al. (1996). For these reasons, it seems that the WLF model over predicts the temperature effect of rate constant (Simatos et al., 1989). As noted by Nelson and Labuza (1994), because of the small temperature range over which foods are stored, e.g., about ∆30°C for dry foods and ∆20°C for frozen foods, both the Arrhenius and the WLF model give good correlations as long as one does not use the universal coefficients suggested by Slade and Levine (1991). In fact as shown by Nelson and Labuza (1994), their use of the Lim and Reid (1991) data for enzymatic activity in the frozen state as shown in 19.3 is not proof that the Arrhenius relationship does not apply, WLF was assumed because the rate was negligible below -10°C which was the measured Tg. But as seen inFigure 19.3b if the data is plotted as Arrhenius plot an r 2 of 0.999 ensues. The challenge in applying the WLF model for stability or shelf life prediction is that (1) T g is not known; (2) T g is difficult to determine; and (3) the universal coefficients of Levine and Slade (1986) are not applicable.Time (hours)R e l a t i v e a b s o r b a n c e 0.00390.00380.00371/T (K -1)l n (k )Figure 19.3 Hydrolysis of maltodextrin in the frozen state (Lim and Reid; 1991)a. Rate as a function of temperature (Note T g is -10 ¡C)b. Arrhenius plot19.2.3.4 Shelf life modelMost published data related to quality deterioration do not give rates or rate constants but rather are in the form of an overall shelf life (end-point analysis) as a function of storage temperature. Since the temperature range used is usually quite narrow, the following exponential relationship exists between shelf life and storage temperature:θ = exp(-bT+c)(19.7a) or ln θ = -bT+c (19.7b)where θ is shelf life at temperature T in °C, b is the slope of the semilog plot of θ vs T and c is the intercept or reference temperature as shown as Fig. 19.4. Practically, this is used frequently for shelf life determination and prediction due to its simplicity and straightforwardness.Figure 19.4 Shelf life plotln θT19.2.3.4 Q 10 or q 10The Q 10 approach is also often used for estimation of the temperature acceleration of shelf life, which is defined as :Q 10 = rate @ T 1+10 °C / rate @ T 1 (19.8a)Q 10 = shelf life @T 1 / shelf life @T 1+10 °C (19.8b) Q 10 = (q 10)1.8(19.8c)where T 1 is temperature in °C. If the temperature unit is in °F, then the term q 10 is used, which in fact is more often used than Q 10 in the frozen food literature.The magnitude of Q 10 depends on the food system, the temperature and the absolute range. Q 10 values from 2 up to 20 have been found for frozen foods (Labuza,1982) Labuza and Schmidl, 1985. Q 10 can be shown to be related to the Arrhenius equation and the shelf life model through the following expression:Q 10 = exp [10 E a /(R T (T+10)](19.9a)Q 10 = exp (10 b)(19.9b)Thus Q 10 is not constant but depends on E a and the absolute temperature T.Some data gleaned from July (1989) and Labuza (1982) is shown in Table 19.2.Table 19.2for shelf life of selected frozen foodsEstimate of the Q10Days of HQLItem-10°C-20°C Q10pork sausage201204pork504008beef60200 3.3ground hamburger 250800 3.2fried hamburger352507raw poultry200700 3.5fried poultry25700 3.2fatty fish 7 60919.2.3.5 Other modelsThe following models have also been proposed to describe the temperature dependence of the rate constant (Kwolek and Bookwalter, 1971) for frozen systems: k T = a + b T(19.10a)k T = a T b(19.10b)k T = a / (b - T)(19.10c)where a, and b are constants. In most cases, Equation 19.10c fits data better. However, all these have very limited practical application.19.2.4 Time-temperature toleranceFrozen foods are often exposed to a variable temperature environment, e.g. during distribution or due to freezing/defrosting cycle in retail or home freezers. In general, the value of the quality function, f(A), at time t under changing environmental conditions can be estimated from:f(A) = ∫ k[T(t)] dt(19.11)where T(t)is the temperature as a function of time. The form of f(A) depends on the reaction order as discussed previously. If an effective temperature, T eff, is defined asthat constant temperature exposure which causes the same quality change as the variable temperature condition, as proposed by Schwimmer et al. (1955), thenf(A) = k eff t(19.12)The rate constant at that defined temperature is termed the effective rate constant, i.e. k eff.To estimate the quality change under variable temperature conditions, one needs to either solve for f(A) numerically or know the value of T eff or k eff thatcorresponds to the variable conditions.The numerical approach for a randomly variable temperature history is essentially the same as the Time/Temperature/Tolerance (TTT) approach initiated by Van Arsdel et al. (1969) and derived empirically in the 1960's for the prediction of shelf life of frozen foods (July, 1984). It is assumed that the temperature history of the product is known. Thus the fraction of shelf life consumed, f con, was calculated as the sum of the times at each temperature interval, t i, divided by the shelf life at that temperature, θi:f con = Σ (t i / θi)(19.13)Thus the remaining shelf life at a reference temperature is equivalent to (1-f con)*θ.Equation 19.13 assumes that the rule of additivity is valid for frozen foods (July, 1984), which means that the loss of remaining storage life or quality can be calculated from knowledge of the prior time-temperature episodes the product has been exposed to. This also implies that the prior sequence of the time-temperature episodes is of no importance except to calculate the amount of quality remaining up to that time, i.e. there is no history effect. If the rule of additivity is valid with reasonable accuracy, the use of time-temperature integrators (TTI) should provide reliable results with respect to prediction of shelf life remaining, which will be discussed later.However, there are some cases where the total effect of various temperature experiences may not be independent of the order in which they occur or of the nature of temperature history. For example, widely fluctuating temperatures may cause freezer burn or in-package desiccation, which is not additive (July, 1984). Where the colloidal nature of a product is affected, the effect of time-temperature history may not be additive either, especially with a freeze/thaw cycles. This is also true when growth of microorganisms occurs (Fu et al., 1991). Certain chemical reactions, enzymatic as well as nonenzymatic, could even proceed more rapidly at temperatures belowfreezing. This is called a negative effect of temperature (Singh and Wang, 1977), which could be caused by one or more of the following factors: (1) a freeze concentration effect; (2) the catalytic effect of ice crystals; (3) a greater mobility of protons in ice than in water; (4) a change in pH, up or down with freezing; (5) a favorable orientation of reactants in the partially frozen state; (6) a salting in or out of proteins; (7) decrease in dielectric constant; and (8) the development of antioxidants at higher temperatures. As has been shown by Fennema (1975), the freeze concentration effect can cause rates of chemical reactions to increase dramatically just below the freezing point (Figure 19.5), e.g. ascorbic acid loss at -3°C can be faster than at higher temperatures this one should not use data in the -4°C to 0°C range or above as part of an accelerated shelf life test to predict rates at lower temperatures. Fennema (1975), showed that the time to 50% loss of vitamin C in broccoli was 44 days at -5°C, 120 days at -2°C and 162 days at +2°C. This concentration effect is evident in the shelf life plot of frozen strawberries as shown in Fig. 19.6 using the data of Guadagni (1968). If the data collected only at 25 and 30°F (-3.9°C and -1.1°C) are used, the predicted shelf life at 0°F (-17.8°C) is over 27 years, if data are collected at only 20 and 25°F (-6.7 and 3.9°C), the shelf life predicted at 0°F is 40 days while data below 20∞F extrapolated to the true expected shelf life is about 280 days.Figure 19.5 Rate of chemical reaction as a function of temperature above and below the freezing point of a food.Figure 19.6. Shelf life plot of frozen strawberries showing the influence of the freeze concentration effect just below the freezing point on prediction of shelf life at 0¡F . Data from Guadagni (1968). Each line represents a regression through a different selected set of temperatures.The response ratio of the food to changes in environmental temperature (R T) is dependent on the fluctuating temperature conditions as well as the heat transfer properties of the food as well as the package (Cairnes and Gordon, 1976; Dagerskog, 1974). In the analysis of food shelf life, an inherent assumption is made that the food is responding instantaneously to the environmental temperature changes, i.e., R T = 1. This may be acceptable if a surface deterioration process is the deterministic factor for shelf life, e.g. mold growth in some foods. Freeze-defrost cycles generally can be considered as sinusoidal oscillations. The amplitude of the effect is reduced inside the package by some factor thus R T. < 1. It can be expected that the shorter the period of the ambient variation the smaller the R T, and hence the smaller the amplitude of the cyclic temperature variation in the package. Zuritz and Sastry (1986) also studied the effect of packaging materials on temperature fluctuations for frozen ice cream and found that packaging materials coupled with a layer of stagnant air were effective barriers against thermal fluctuations.19.2.5 Hazard functionAfter the product is produced, it may fail at any point in time in accordance with its life distribution (Nelson, 1972). The hazard function h(t) of a distribution is defined for t ≥ 0 by:h(t) = f(t)/[1-F(t)](19.14)where f(t) is a probability density function and F(t) is a cumulative distribution function. The h(t) is the conditional probability of failure at time t, given that failure has not occurred before ..The behavior of a hazard function for studying the shelf life of food products can be easily understood by examining the "bathtub" shaped curve in Fig. 19.7. Note that at time t o, a frozen food product begins its journey to many distribution outlets for consumption. During the time between t o and t1, early failures may occur owing to a failure in the process itself, faulty packaging, extreme initial product abuse, and many other environmental stresses to which the product is subjected. Early failure should not be taken as a true failure relative to the shelf life of the product unless it represents the normal condition. From t1 to t2 one can expect, barring chance major temperature fluctuations, no failures. This interval represents the true period of the product's stability. The failure rate is almost constant and small during this time. The hazard or failure rate increases from time t2 to the termination point t3, owing to the true deteriorative changes occurring within the product. The concept of hazard function is important in the analysis and interpretation of the failure times of a product.A fundamental assumption underlying statistical analysis of shelf life testing is that the shelf life distribution of a food product belongs to a family of probability distributions and that observations are statistically independent. Parameters of a shelf life distribution are estimated by use of shelf life testing experimental data. Once the parameters of a shelf life model have been estimated, it can be used to predict the probabilities of various events, such as future failures (Nelson, 1972). Five statistical models, normal, log normal, exponential, Weibull and extreme-value distributions were tested for a few food products (Gacula and Kubala, 1975; Labuza and Schmidl, 1988) and it was found that the Weibull distribution fits best, which will be demonstrated later.19.3Shelf life testing — overall aspects19.3.1 PurposeIn the development of any new food product including reformulating, change of packaging or storage/distribution condition (to penetrate into a new market), one important aspect is the knowledge of shelf life. The shelf life of a food product is vital to its success in the marketplace. This life must at least exceed the minimum distribution time required from the processor to the consumer. Shelf life testing can assess problems that the product has in the development stage, following a "fail small fail early" philosophy, thereby eliminating large disasters later. Marketing/brand managers also need reliable shelf life data to position the products and to establish the brand. Periodic determination of shelf life help to provide assurance that the product remains consistent over time with respect to quality.Different shelf life testing strategies are necessary at different stages, as illustrated in Fig. 19.8. If the objective is to identify whether pathogens and spoilage microbes will grow in the case of temperature abuse, then a challenge study is necessary. If the objective is to quickly estimate the approximate shelf life of the product then an ASLT can be used, as long as the proper temperature range is chosen. A confirmatory shelf life test may be conducted at the last stage with simulated distribution chain conditions, although in today’s R & D environment, this may be skipped.Figure 19.8 Shelf life testing strategy at different product development stages19.3.2 Shelf life criteriaThe criterion for the end of shelf life may be variable depending on the definition of product quality grade, so the shelf life of a product may also be variable. The shelf life of most perishable and semiperishable foods is almost solely based on sensory quality. For example, fresh meat degrades mainly by bacterial activity and rapid chemical oxidations that cause an off-flavor development and loss of color. This is readily recognizable by consumers. In contrast, many longer shelf-life foods including most frozen foods degrade mainly by slow chemical reactions such as loss of nutritional value. For example, the vitamin C content of some frozen fruits and vegetables, may fall below the required standard as listed on the label before sensory quality becomes inadequate.The criteria for shelf life may also vary depending on the sensitivity of the consumer. For consumers, taste, odor, and appearance are the most obvious criteria; in academia and in the industry, sensory evaluation correlated with instrumental measurements of a given quality index (e.g., vitamin C level) are usually conducted. In general, the criteria level corresponding to the end of shelf life of a product dependson: (i) any legal requirement, e.g. zero tolerance for botulinum toxin; (ii) consumer preferences or marketing requirements; and (iii) cost. In essence, the end of shelf life depends on the percentage of consumers a company is willing to displease. If 100% acceptance is required then high cost ingredients and absolute control of distribution up to point of consumption is necessary, otherwise there will always be some people who will get foods beyond shelf life. The aim is to keep this as small as possible.19.3.2.1 Just noticeable difference (JND)Sensory (organoleptic) examination of foods was a general procedure used by the human race to evaluate wholesomeness of foods long before the discovery of microorganisms. Sensory evaluation of foods by scientific methods can be used to evaluate such attributes as taste, odor, body, texture, color and appearance. Changes in these attributes may be brought out by microbial or non-microbial actions, usually the latter for frozen foods.The methods used to evaluate sensory shelf life data include difference testing and hedonic scoring. Difference testing can involve paired comparisons, duo-trio tests, or triangle tests. The paired comparison procedure determines the time when a measurable difference in quality occurs between two test samples at a certain level of probability. When applied to frozen foods, this method is often referred to as the Just Noticeable Difference (JND) test or High Quality Life (HQL) test (July, 1984), which is usually based on flavor changes. Duo-trio testing compares two unknowns to an unabused control sample and asks the question of whether either of the unknowns are the same as or different from the identified control. Triangle testing determines the one different product among three test samples presented randomly to a set of judges (at least 10). Probability plots are used to predict shelf life at a given probability level. The difference method can result in finding a difference when none really exists (Type I error), or not finding one when indeed there is a true difference (Type II error). Labuza and Schmidl (1988) have discussed this topic more thoroughly in relationship to shelf life testing, which is not commonly found in sensory textbooks. Table 19.3 shows some data from Guadagni (1968) for HQL of frozen foods.。

【英语阅读】Shelf Life(货架人生)

Shelf Life货架人生（shelf life也有“保质期”之意——译者注）By Anthony DanielsIf you ask anyone for his idea of a dead-end job, the chances are that he will reply “stacking supermarket shelves.”如果你问任何人他对无出路的工作的想法，他很可能会回答：“整理超市的货架。

”This occupation, indeed, has become a trope for the futility of existence at the lower end of the social spectrum. Not long ago, for example, a columnist in the Guardian wrote that 1) it was scarcely any wonder that teenage girls had babies when the only alternative open to them was stacking supermarket shelves. As far as she was concerned, having a baby could 2) prevent a worse fate.这个职业，事实上，已经成为社会的底端生存无用的比喻。

例如，不久前《卫报》的专栏作家写道，几乎毫无疑问，一个十几岁的女孩有了孩子，她唯一的选择就是去整理超市货架。

在她看来，有孩子能避免更糟糕的命运。

But if supermarkets are necessary, then so are supermarket shelves—they have to be stacked by someone.但如果超市是必要的，那么超市的货架也是——必须有人来整理它们。

Leadfree与Halogenfree

¾無鉛wetting time : 2秒，Sn63 : 0.6秒¾SnCu熔點227 ℃，會對板材與綠漆造成軟化與傷害，易氧化、短路或空銲。

市场营销ppt图片课件

30
Media Adv
20
Cons. Promo
10
0
1986 88 90 92 94 1996
Year ©2000 Prentice Hall Cox Direct 19th Annual Survey of Promotional Practices
在日常生活中，随处都可以看到浪费粮食的现象。也许你并未意识到自己在浪费，也许你认为浪费这一点点算不了什么
selectivity; low cost
Limitations:
Audio only; fleeting exposure; lower attention;
nonstandardized rates; fragmented audiences
Magazines Advantages:
High geographic and demographic selectivity; credibility and prestige; high-quality reproduction; long life; good pass-along readership
在日常生活中，随处都可以看到浪费粮食的现象。也许你并未意识到自己在浪费，也许你认为浪费这一点点算不了什么
Objectives
Developing & Managing an Advertising Program Deciding on Media & Measuring Effectiveness Sales Promotion Public Relations
©2000 Prentice Hall
在日常生活中，随处都可以看到浪费粮食的现象。也许你并未意识到自己在浪费，也许你认为浪费这一点点算不了什么

the shelf-life of foods

Concepts

Shelf-life in GB 7718-2004,Pre-packaged foods specified on the label storage conditions, the duration of the shelflife quality. Over this period, within a certain time, pre-packaged food may still be edible.
View” Reporters recently tracked in Beijing, Hunan who found that some merchants borrow printing machinery, toxic chemicals and other “props” to alter food shelf as a “juggler” .
The third is elastic type label The shelf life marked on the label from 1 month to 3 months. Should had the food has gone bad，manufacturers, distributors could be argued that its shelf-life is one month; should had the goods be still selling after a month , they will turn claims that its shelf life up to three months.
The shelf-life of foods
Food science and engineering college Food quality and safety, Class 2 Grade 09

湖北省武汉市部分重点中学2023-2024学年高二上学期期末联考英语试卷

武汉市部分重点中学20232024学年度上学期期末联考高二英语试卷命审题单位：武汉六中英语学科组审题单位：圆创教育研究中心湖北省武昌实验中学本试卷共10页，67题。

满分150分。

考试用时120分钟。

考试时间：2024年1月24日下午14：0016：00★祝考试顺利★注意事项：1. 答题前，先将自己已的姓名、准考证号填写在试卷和答题卡上，并将准考证号条形码贴在答题卡上的指定位置。

2. 选择题的作答：每小题选出答案后，用2B铅笔把答题卡上对应题目的答案标号涂黑。

写在试卷、草稿纸和答题卡上的非答题区域均无效。

3. 非选择题的作答：用黑色签字笔直接答在答题卡上对应的答题区域内。

写在试卷、草稿纸和答题卡上的非答题区域均无效。

4. 考试结束后，请将本试卷和答题卡一并上交。

第一部分听力(共两节，满分30分)第一节(共5小题；每小题1. 5分，满分7. 5分)听下面5段对话。

每段对话后有一个小题，从题中所给的A、B、C三个选项中选出最佳选项。

听完每段对话后，你都有10秒钟的时间来回答有关小题和阅读下一小题。

每段对话仅读一遍。

例：How much is the shirt?A. ￡19. 15.B. ￡9. 18.C. ￡9. 15.答案是C。

1. What will the speakers do on Thursday?A. Play football.B. Watch a movieC. Go hiking.2. What does the man want to do?A. Place an order.B. Design a uniform.C. Form a team.3. What is Sally’s favorite city?A. Paris.B. Madrid.C. Venice.4. Where will the speakers go?A. To a cafe.B. To a dessert shop.C. To a bookstore.5. What relation is Mr. Gomez to the man?A. His teacher.B. His client.C. His boss.第二节(共15小题；每小题1. 5分，满分22. 5分)听下面5段对话或独白。

PGD-01 PERMA-GUARD

Form: GDH-77 1 .DESCRIPTION AND USES .Perma-Guard ™Mold & Mildew-Proof ™Interior Sealer is a high performance acrylic interior sealer formulated to protect interior surfaces while preventing mold & mildew growth on the paint film. Perma-Guard is designed toproduce a tough, durable, washable finish that withstands moisture and resists dirt pick up. It protects and restores the soundness of new, aged or water damaged material against mold and moisture.It is suitable for application to interior walls, wall cavities, trusses, frame and interior side OSB lumber, unfinished cement block basements and related surfaces. It is recommended for interior use on new or previously painted gypsum drywall, cured plaster, cement, poured concrete and stucco, concrete block, ceramic tile, wood and metal. Seals porous and semi-porous construction surfaces and provides a moisture resistant finish. Perma-Guard can be used for residential, institutional or commercial use in schools, hospitals, hotels, nursing homes, restaurants and athletic facilities. DAMP SURFACESPerma-Guard may be applied over damp surfaces but isnot designed to stop active water leaks. Use Water-Tite®Mold & Mildew-Proof ™Waterproofing Paint for masonry prone to water intrusion. Perma-Guard may be used over any quality waterproofing paint to prevent mold and mildew growth on the paint film.PERFORMANCE CHARACTERISTICS .∙ Antimicrobial – Inhibits the growth of odor causing microbes on the paint film∙ Self-priming – Applies white and dries clear∙ Excellent adhesion – Bonds to glossy and hard-to-paint surfaces∙ Durable – Non-corrosive and moisture resistant finish ∙ Low odor, fast drying – Recoat in 2 hours ∙Soap and water clean-up.PRODUCTS .SKU Description02680 5-Gallon 02681 1-GallonPRODUCT APPLICATION .SURFACE PREPARATIONSurfaces should be clean, dry, sound and free of dust, dirt, grease, wax, wallcovering adhesive, soap film, loose paint or any contamination that may interfere with adhesion. Remove all existing mold and mildew before painting. If you are concerned about mold and mildew behind walls, underneath flooring, in ventilation systems or other unseen areas, contact a professional who specializes in mold and mildew remediation. For commercial buildings andschools, follow appropriate guidelines for mold removal. To effectively kill mold and mildew and clean surfaces, use Perma-Wash Disinfectant and Fungicide Interior Concentrate or a suitable biocidal wash.WARNING! If you scrape, sand or remove old paint, you may release lead dust. LEAD IS TOXIC. EXPOSURE TO LEAD DUST CAN CAUSE SERIOUS ILLNESS, SUCH AS BRAIN DAMAGE, ESPECIALLY IN CHILDREN. PREGNANT WOMEN SHOULD ALSO AVOIDEXPOSURE. Wear a NIOSH-Approved respirator to control lead exposure. Clean up carefully with a HEPA vacuum and a wet mop. Before you start, find out how to protect yourself and your family by contacting the National Lead Information Hotline at 1-800-424-LEAD or log on to /lead. STAINSSeal all stains and wood knots with Bulls-Eye ®Shellac before coating. When sealing over stained areas, attempt to remove as much of the stain as possible by washing, sanding, scraping, etc. APPLICATIONTwo coats are required for proper performance and mold & mildew-proof resistance. Apply only when air, material, and surface temperatures are between 50-90ºF (10-32ºC) and the relative humidity is below 80%. Shake or mix thoroughly before using. May be applied to a damp surface.Apply with a synthetic (nylon, polyester or blend) bristle brush, roller, or airless sprayer. Follow manufacturer's instructions when using spray equipment. For airless spraying use a 0.015" tip at 900-1500 psi. Wear NIOSH approved respirator and provide adequate ventilation.Form: GDH-772 .PRODUCT APPLICATION (cont.) .LIMITATIONSPerma-Guard Mold & Mildew-Proof Interior Sealer is not intended for application to floors, HVAC ductwork, or any surface subject to immersion or prolonged contact with water including shower enclosures, saunas or steam rooms. Not designed as a water-proofer. DRY TIMEDries to the touch in 30 minutes and can be recoated 2 hours after applying the first coat. Scrape resistance over glossy surfaces develops in 5 to 7 days. Do not scrub the new coating for seven days. CLEAN-UPClean up spills and paint drips with detergent and warm water. Wash application tools in detergent and warm water immediately use. If product has dried on application tools, soak overnight in a solution of equal parts household ammonia and water. Follow equipment manufacturer’s directions to clean spray equipment. Dispose of unused or unwanted product in accordance with local laws regulating water-based coatings. STORAGEKeep lid tightly closed during storage. Protect from freezing. If contents freeze, thaw to room temperature before using.Rust-Oleum Corporation Form: GDH-77 11 Hawthorn Parkway Phone: 877•385•8155.PHYSICAL PROPERTIES .The technical data and suggestions for use contained herein are correct to the best of our knowledge, and offered in good faith. The statements of this literature do not constitute a warranty, express, or implied, as to the performance of these products. As conditions and use of our materials are beyond our control, we can guarantee these products only to conform to our standards of quality, and our liability, if any, will be limited to replacement of defective materials. All technical information is subject to change without notice.。

shelf life extension program 结论汇总

shelf life extension program 结论汇总Shelf Life Extension Program ConclusionsIntroduction:The Shelf Life Extension Program (SLEP) is an important initiative undertaken by various industries to ensure that products remain viable and safe for extended periods of time. In this article, we will summarize the conclusions drawn from the SLEP and highlight the key findings.I. Background of the Shelf Life Extension Program:The SLEP was established with the aim of assessing the stability and viability of products beyond their designated expiration dates. It involves conducting extensive testing and evaluation to determine whether these products can still be utilized effectively and safely.II. Findings from the Shelf Life Extension Program:1. Stability of Pharmaceuticals:The SLEP has shown that many pharmaceuticals remain stable and retain their potency beyond their printed expiration dates. This finding is significant as it reduces unnecessary waste and allows for the safe use of medications that would otherwise be discarded.2. Nutritional Supplements:The SLEP also yielded positive results for nutritional supplements, indicating that they can retain their nutritional value even after their statedexpiration dates. This is crucial information for manufacturers, retailers, and consumers.3. Food and Beverages:The SLEP findings have highlighted that certain food and beverage products can remain safe for consumption beyond their indicated expiration dates. This information is particularly valuable during times of crisis, such as natural disasters, when access to fresh food is limited.4. Cosmetics and Personal Care Products:The stability testing conducted as part of the SLEP has shown that certain cosmetics and personal care products can remain safe and effective for longer periods. This finding has implications for the consumer, allowing them to make informed decisions about product usage.5. Environmental Impact:The SLEP has shed light on the environmental benefits of employing shelf life extension techniques, as it reduces waste and minimizes the disposal of still usable products. This finding supports the push for sustainability and responsible resource management.III. Recommendations:Based on the conclusions drawn from the Shelf Life Extension Program, the following recommendations can be made:1. Regulatory Guidelines:Regulatory authorities should consider revising guidelines and regulations regarding expiration dates, taking into account the findings fromthe SLEP. This will ensure accurate labelling, reducing unnecessary product waste and improving consumer confidence.2. Consumer Education:Manufacturers and retailers should actively educate consumers about the potential extended shelf life of products. This will enable consumers to make informed decisions and avoid unnecessarily discarding items that are still safe and effective.3. Continued Research and Testing:The SLEP should continue to be supported, and further research and testing should be conducted to expand the knowledge base surrounding shelf life extension. This will help identify additional products and sectors where extended shelf life can provide significant benefits.Conclusion:The Shelf Life Extension Program has demonstrated that many products, including pharmaceuticals, nutritional supplements, food and beverages, and cosmetics, can maintain their quality and safety beyond their indicated expiration dates. These findings have important implications for waste reduction, environmental impact, and consumer well-being. By implementing the recommendations mentioned, we can optimize the use of these products and contribute to a more sustainable future.。

Avago Technologies ASMT-Rx45 0.45mm Leadframe-Base

ASMT-Rx45-xxxxx 0.45mm Leadframe-Based Surface Mount ChipLED
Data Sheet
Description
Avago Technologies’ ultra-thin ASMT-Rx45 ChipLEDs were developed based on the industrial standard ChipLED 0603 platform which requires less board space. These ChipLEDs provide a wide viewing angle of 130 degrees to improve visibility in bright sunlight.
CAUTION: ASMT-Rx45 LEDs are Class 1C ESD sensitive per JESD22-A114C.01. Please observe appropriate precautions during handling and processing. Refer to Application Note AN-1142 for additional details.
Min 5 5 5 5
Thermal Resistance RqJ-PIN (°C/W) Typical 246 246 246 246
Optical Characteristics at TA = 25°C
Part Number ASMT-RR45 ASMT-RJ45 ASMT-RF45 ASMT-RA45
2. The dominant wavelength, ld, is derived from the CIE Chromaticity Diagram and represents the perceived color of the device. 3. q½ is the off-axis angle where the luminous intensity is ½ the peak intensity.

炭材料在铅酸电池中的应用.kdh

收稿日期：２０１０－０４－２４作者简介：张浩（１９８１—），男，河南省人，博士后，主要研究方向为超级电容器与锂离子电池。

联系人：张浩，ｄｒ．ｈ．ｚｈａｎｇ＠ｈｏｔｍａｉｌ．ｃｏｍ炭材料在铅酸电池中的应用张浩，曹高萍，杨裕生(防化研究院，北京100191)摘要：超级电池与铅炭电池是两类具有高功率、长寿命性能的新型铅酸电池，其性能突破均是依靠将高比表面炭材料或炭电极用到铅酸电池中。

两种器件的关键技术也有相似之处：适合于硫酸电解液的高性能电容炭材料。

综述了近年来炭材料在铅酸电池中的应用进展，并对炭材料的作用机制进行讨论。

关键词：铅蓄电池；超级电池；铅炭电池；炭材料；改性中图分类号：ＴＭ９１２．９文献标识码：Ａ文章编号：１００２－０８７Ｘ（２０１０）０７－０７２９－０５Application of carbon materials in lead acid batteriesZHANG Hao,CAO Gao-ping,YANG Yu-sheng(Research Institute of Chemical Defense,Beijing 100191,China)Ａｂｓｔｒａｃｔ：Ｕｌｔｒａｂａｔｔｅｒｙａｎｄｌｅａｄ－ｃａｒｂｏｎｂａｔｔｅｒｙａｒｅｔｗｏｋｉｎｄｓｏｆｎｏｖｅｌｌｅａｄ－ａｃｉｄｂａｔｔｅｒｉｅｓｏｂｔａｉｎｉｎｇｈｉｇｈｐｏｗｅｒｄｅｎｓｉｔｙａｎｄｌｏｎｇｃｙｃｌｅｌｉｆｅ，ａｎｄｔｈｅｉｒｂｒｅａｋｔｈｒｏｕｇｈｉｎｐｅｒｆｏｒｍａｎｃｅｒｅｌｉｅｓｏｎｔｈｅａｐｐｌｉｃａｔｉｏｎｏｆｈｉｇｈｓｕｒｆａｃｅａｒｅａｃａｒｂｏｎｍａｔｅｒｉａｌｓｏｒｃａｒｂｏｎｅｌｅｃｔｒｏｄｅｓｉｎｔｏｔｈｅｌｅａｄａｃｉｄｂａｔｔｅｒｉｅｓ．Ｔｈｅｋｅｙｔｅｃｈｎｏｌｏｇｙｏｆｔｈｅｓｅｔｗｏｃｅｌｌｓｉｓｓｉｍｉｌａｒ：ｈｉｇｈｐｅｒｆｏｒｍａｎｃｅｃａｐａｃｉｔｏｒｃａｒｂｏｎｍａｔｅｒｉａｌｓｓｕｉｔａｂｌｅｆｏｒＨ２ＳＯ４ｅｌｅｃｔｒｏｌｙｔｅｓ．Ｔｈｅｐｒｏｇｒｅｓｓｏｆｔｈｅａｐｐｌｉｃａｔｉｏｎｏｆｃａｒｂｏｎｍａｔｅｒｉａｌｓｉｎｌｅａｄ－ａｃｉｄｂａｔｔｅｒｉｅｓｗａｓｒｅｖｉｅｗｅｄａｎｄｔｈｅｍｅｃｈａｎｉｓｍｏｆｔｈｅｍｗａｓｄｉｓｃｕｓｓｅｄｉｎｔｈｉｓｐａｐｅｒ．Ｋｅｙｗｏｒｄｓ：ｌｅａｄ－ａｃｉｄｂａｔｔｅｒｉｅｓ；ｕｌｔｒａｂａｔｔｅｒｉｅｓ；ｌｅａｄ－ｃａｒｂｏｎｂａｔｔｅｒｉｅｓ；ｃａｒｂｏｎｍａｔｅｒｉａｌｓ；ｍｏｄｉｆｉｃａｔｉｏｎ2009年8月，美国总统奥巴马宣布，拨款24亿美元支持美国48个项目发展“下一代电池和电动车”生产，其中用于电池及其材料生产的为15亿美元。

shelf life

shelf lifeShelf LifeIntroductionShelf life refers to the length of time a product can be stored before it is no longer fit for use or consumption. It is an important consideration for both businesses and consumers as it affects the quality, safety, and nutritional value of the products we buy. In this document, we will explore the concept of shelf life, factors that influence it, and ways to extend the shelf life of various products.Factors Affecting Shelf LifeShelf life can vary significantly depending on several factors. Some of the key factors that influence the shelf life of products include:1. Product Type: Different products have different shelf lives. For example, fresh produce like fruits and vegetables have a shorter shelf life compared to canned or frozen varieties.Similarly, perishable items like dairy products and meats generally have a shorter shelf life compared to dried goods.2. Packaging: The type of packaging used also plays a crucial role in determining the shelf life of a product. Proper packaging can help protect against factors like moisture, oxygen, and light, which can contribute to spoilage. Vacuum-sealed packaging, for instance, can help extend the shelf life of food products.3. Temperature: Temperature is a critical factor that affects the shelf life of perishable items. Most products require specific temperature conditions to maintain their quality and safety. For example, storing perishable food items at temperatures above the recommended range can promote bacterial growth and spoilage, thereby reducing their shelf life.4. Storage Conditions: Besides temperature, storage conditions such as humidity and exposure to sunlight can also impact shelf life. Products that are stored in a cool, dry, and dark environment generally have a longer shelf life compared to those exposed to unfavorable conditions.Extending Shelf LifeExtending the shelf life of products is essential for minimizing wastage and ensuring consumer satisfaction. Here are some tips to help extend the shelf life:1. Proper Storage: Follow the recommended storage instructions provided by the manufacturer. This may include keeping products refrigerated, frozen, or stored in a dry pantry. Adhering to the specified storage conditions can help maintain the product's quality and shelf life.2. Use-By Dates: Pay attention to the use-by or expiration dates on products and consume them before they expire. These dates are determined by manufacturers and indicate the estimated period of time during which the product will be at its peak quality.3. Freezing and Canning: Freezing and canning are effective preservation methods that can prolong the shelf life of many food products. Freezing slows down the growth of bacteria and other microorganisms, while canning creates a sealed environment that prevents spoilage.4. Oxygen Barrier Packaging: Investing in oxygen barrier packaging can help protect products from the deteriorating effects of oxygen. This type of packaging is commonly used for products like coffee beans, biscuits, and snacks, and helps maintain their freshness for a longer time.ConclusionShelf life is a crucial consideration for both businesses and consumers. By understanding the factors that influence shelf life and implementing proper storage and preservation techniques, we can ensure that products remain safe, nutritious, and of good quality for an extended period. Adhering to use-by dates and investing in proper packaging can go a long way in reducing wastage and maximizing the shelf life of various products.。

IT-158

IT-158
Mid-Tg, Low-CTE, Multifunctional Epoxy Resin with Fillers, Phenolic-Curing, Lead-free Process Compatible
Process Guideline
1. Prepreg Handling & Storage (1) Shelf life is at least 3 months when prepreg stored in a cool dry environment (Temperature: <20℃ Humidity: <50%).
4. Lamination Overview (1) Stacks must be prepared in lay-up room to avoid moisture absorption.
(2) Stacks with the core and prepreg are recommended to use the vacuum process for 30 minutes before heated. Recommended
Specification
180/90
<1.5 -
V-0 -
Units
Test Method
Days
AABUS
As per IPC-4412 or AABUS
%
2.3.19
AABUS
AABUS
rating
UL94
Ref. Para
3.17
3.9.2.2.8 1.1.7
3.10.2.1
2
Your best Partner for High Performance Laminate & Masslam Service

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9Figure 2.Group 1A NiPdAu 0.01-m m (0.4-m ”) Pd, Loose, 96 h, 25y , Bottom Lead View Figure 3.Group 1A NiPdAu 0.01-m m (0.4-m ”) Pd,Loose, 96 h, 200yFigure 4.Group 2A NiPdAu 0.02-m m (0.8-m”)Pd, Loose, 96 h, 25yFigure 5.Group 2A NiPdAu 0.02-m m (0.8-m”)Pd, Loose, 96 h, 200yFigure 6.Group 3A NiPdAu 0.02-m m (0.8-m”)Pd, Loose, 96 h, 25yFigure 7.Group 3A NiPdAu 0.02-m m (0.8-m”)Pd, Loose, 96 h, 200yFigure 8.Group 6A NiPdAu 0.02-m m (0.8-m”) Pd, Loose, 96 h, 25yFigure 9.Group 6A NiPdAu 0.02-m m (0.8-m”) Pd, Loose, 96 h, 200yAuger also confirmed that the Cu-bearing compound deposits seen in the micrographs are thin. Twenty seconds of sputtering was sufficient to bring the surface composition of an area with corrosion products to that of a corrosion-free area. (This thickness is roughly equivalent toFigure 10.Reflow Profile Used for 20-Pin SOIC Units Figure 11.Reflow Profile Used for 16-Pin SOIC UnitsFigure 12.Group 1A, NiPdAu Finish, Stored Loose, 96-h Exposure Figure 13.Group 1B, NiPdAu Finish, Stored in Tubes, 96-h ExposureFigure 14.Group 2A, NiPdAu Finish, Stored Loose, 96-h Exposure Figure 15.Group 2B, NiPdAu Finish, Stored in Tubes, 96-h ExposureFigure 16.Group 3A, NiPd Finish, Stored Loose, 96-h Exposure Figure 17.Group 3B, NiPd Finish, Stored in Tubes, 96-h ExposureFigure 18.Group 4A, Sn Finish, Stored Loose, 96-h Exposure Figure 19.Group 4B, Sn Finish, Stored in Tubes, 96-h ExposureFigure 20.Group 5A, SnPb Finish,Figure 21.Group 5B, SnPb Finish,Figure 22.Group 6A, NiPdAu-Ag Finish, Stored Loose, 96-h Exposure Figure 23.Group 6B, NiPdAu-Ag Finish, Stored in Tubes, 96-h ExposureAll groups exhibited good solder wetting. For all groups (1–6), all units exhibited good solderIMPORTANT NOTICETexas Instruments Incorporated and its subsidiaries(TI)reserve the right to make corrections,modifications,enhancements,improvements, and other changes to its products and services at any time and to discontinue any product or service without notice.Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment.TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard warranty.Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty.Except where mandated by government requirements,testing of all parameters of each product is not necessarily performed.TI assumes no liability for applications assistance or customer product design.Customers are responsible for their products and applications using TI components.To minimize the risks associated with customer products and applications,customers should provide adequate design and operating safeguards.TI does not warrant or represent that any license,either express or implied,is granted under any TI patent right,copyright,mask work right, or other TI intellectual property right relating to any combination,machine,or process in which TI products or services are rmation published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a warranty or endorsement e of such information may require a license from a third party under the patents or other intellectual property of the third party,or a license from TI under the patents or other intellectual property of TI.Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties,conditions,limitations,and notices.Reproduction of this information with alteration is an unfair and deceptive business practice.TI is not responsible or liable for such altered rmation of third parties may be subject to additional restrictions.Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice.TI is not responsible or liable for any such statements.TI products are not authorized for use in safety-critical applications(such as life support)where a failure of the TI product would reasonably be expected to cause severe personal injury or death,unless officers of the parties have executed an agreement specifically governing such use.Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications,and acknowledge and agree that they are solely responsible for all legal,regulatory and safety-related requirements concerning their products and any use of TI products in such safety-critical applications,notwithstanding any applications-related information or support that may be provided by TI.Further,Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in such safety-critical applications.TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are specifically designated by TI as military-grade or"enhanced plastic."Only products designated by TI as military-grade meet military specifications.Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is solely at the Buyer's risk,and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use. 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