冷藏、冷加工制冷剂选择

本文通过分析了不同制冷剂的基本性质、使用现状,对冷冻冷藏及冷加工制冷剂的选择进行了探讨     

V-4Cr-4Ti合金的时效与冷加工强化

利用力学性能测试和微观结构观察,研究了V-4Cr-4Ti合金的时效与冷加工强化,以及冷加工与氧含量对时效进程的影响.结果表明:钒合金在时效处理过程中产生了Ti-(C,O,N)沉淀相,其中650℃×3 h时效处理的V-4Cr-4Ti合金可以取得比较好的综合力学性能;时效与冷加工能对该合金起到综合的强化效果,但冷加工对时效进程有抑制作用.另外,氧含量增加对该合金的时效强化进程有促进作用.     

冷藏链现状及进展

冷藏链系统是保证易腐产品质量最重要的保障技术措施.通过分析国内蔬菜、水果、肉产品、水产品、冷饮等易腐产品的市场发展趋势,指出发展冷藏链技术是保证我国易腐产品可持续发展的重要保障.在这基础上,从冷藏链流程上分析了国内冷藏链关键技术的现状和不足,包括预冷技术、冷藏运输技术、冷藏库技术及冷藏链末端技术.最后对国内发展冷藏链技术的方向进行了阐述,包括冰温技术、无线信息管理技术.这些工作将为发展和健全我国冷藏链系统起指导作用.     

5083铝合金板材折角加工的研究

研究了5083高强度铝合金板材折角加工性能,通过工艺试验,确定出铝合金板材冷加工的最佳方案和工艺参数,以确保铝合金板材冷加工成型质量,满足结构设计和隐身设计的要求。     

冷库技术管理交流会在柳州召开

商业系统肉类加工冷藏企业中南区技术协作组于不久前在广西柳州召开了“冷藏技术和冷库管理经验交流会”,参加会议的有中南五省(区)的肉联、冷冻厂、禽蛋厂等55个单位77名科技管理人员。在会上进行交流的有肉、蛋冷加工工艺,冷库制冷系统的节能,冷库排管自动扫霜装置,冷库除霉和冷库管理等方面的论文和总结共20篇,大致地反映了中南地     

食品加工类企业冷加工、冷藏设施宏观节约概述

食品加工类企业冷加工、冷藏设施宏观节约的关键点在确定经营意图并据此完成工程设计的阶段，重要保障是合理的工程项目运作模式。找到固定资产投资和运行费用的均衡点是在确定经营意图并据此完成工程设计阶段的主要工作目标之一。     

冷藏集装箱热工性能测试装置设计

本文将对冷藏集装箱测试装置--环境室进行设计,设计参数参照ATP协议、ARI-1110标准及ABS标准,运用校准箱法进行测试.设计的方案满足了用户设计的需求.     

基于风机盘管加新风系统的空调系统自动控制实验室设计与建设方案研究

通过对高职制冷与冷藏专业工学结合的课程体系重塑工作的认识和理解,阐述了基于风机盘管加新风系统的空调系统自动控制实验室设计与建设的目的和重要意义,确定了该设计与建设方案的三个基本原则,并在此基础上提出了以现代电子控制系统与传统机电式控制装置相结合,以对空调机组自动控制与现场手动测控相结合的基于风机盘管加新风系统的空调系统自动控制实验室设计与建设方案.并进一步阐述了该方案在高职制冷与冷藏专业实验实训教学中六个方面的重要作用.     

城市岩体爆破方案优选的熵模糊物元决策模型

针对城市岩体爆破方案综合评价中各指标的不相容性,从破岩效果和环境因素2个角度出发,选用根底率、价格比、耗时比、振速、声压、声持续等指标,将信息熵理论与模糊物元理论相结合,建立了基于熵权的城市岩体爆破方案优选的模糊物元评价模型.利用该模型对重庆市区中某商业城平基工程岩石爆破方案进行评价,以待选方案与最优方案间的海明贴近度来决策综合效益最优的方案,并与模糊综合评判法的评价结果进行比较.研究结果表明:该模型引用信息熵所反映数据本身的效用值来计算指标的权重系数,有效地避免了权重分配困难的问题,并可得出评价样本与评价标准之间的远近关系,与实际情况相符,进而为城市岩体爆破方案综合评价提供了一种新思路.     

GH625合金的冷变形及其对力学性能的影响

研究了冷加工变形量对GH625合金板材力学性能的影响。研究表明,随冷加工变形量的增加,GH625合金的拉伸强度增加,但塑性降低。冷加工变形量对待持久寿命和冷热疲劳性能影响显著,20％左右的冷变形量可使合金具有最挂的持久寿命和疲劳性能及良好的综合力学性能。合金冷作硬化效果与合金的回复和再结晶程度及固溶化处理温度有关。     

First results of a pilot installation of a solar thermally driven cold store

Within the scope of the project AgroKühl, a pilot plant of a solar thermally driven cold store has been developed and installed near Freiburg in Germany. The system consists of a linear concentrating Fresnel collector system with mirror area of 88 m², an ammonia-water absorption chiller of 12 kW cooling capacity with an integrated cooling tower, two ice storages of 52 kWh latent storage capacity and a cold store of 100 m³. With the aim to guarantee observation of quasi-realistic system behaviour and to avoid restrictions in the operation, the cold store was equipped with computer-controlled fan heaters and humidifiers. This allows the emulation of sensible and latent loads in the room. The system was installed in summer 2012 and since August 2012 it is in continuous operation during summer period. This publication describes the system in detail, summarizes the first operational results and highlights optimization potential of the plant.     

地下电缆隧道通风设计及分析

比较了自然通风与机械通风,介绍了地下电缆隧道通风需要满足的几种运行工况,结合隧道实际布局给出了合理的通风方式,并指出在通风设计过程中应注意的几个问题;重点介绍及探讨了地下电缆隧道内通风机房的设置和通风区段的划分、发热量和通风量的计算、隧道断面风速的控制、工艺控制等,以期对类似工程具有参考价值。     

小型数据中心机房布局及气流组织研究

以实际项目的机房为例,通过CFD模拟的方法研究小型机房的合理布局形式,分析各形式下的温度和速度分布情况,利用热环境评价指标来评价冷却效果,并对刚投入使用的机房进行了实验测试。研究表明,敞开式冷热通道的两侧和顶部都存在冷热空气掺混现象,降低了冷空气的利用效率;在机房尺寸允许的情况下,空调送风方向应与冷热通道平行,布置机架时应尽量增加每排的机柜数量;当机房发热量较小时,冬季室外空气的自然冷量可以满足冷却要求;封闭冷通道的方式可以减少冷空气短路,提高冷却效率。     

Simulation of special bubble detectors for PICASSO

The PICASSO project is a cold dark matter (CDM) search experiment relying on the superheated droplet technique. The detectors use superheated freon liquid droplets (active material) dispersed and trapped in a polymerised gel. This detection technique is based on the phase transition of superheated droplets at about room temperature and ambient pressure. The phase transition is induced by nuclear recoils when an atomic nucleus in the droplets interacts with incoming subatomic particles. This includes CDM particles candidate as the neutralino (a yet-to-discover particle predicted in extensions of the standard model of particle physics). Simulations performed to understand the detector response to neutrons and alpha particles are presented along with corresponding data obtained at the Montreal Laboratory.     

大型LNG储罐底部泡沫玻璃绝热层保冷性能

通过理论分析和工程实例对比计算,得出泡沫玻璃绝热保冷层厚度与储罐底部冷损失、蒸发量、蒸发率关系式和关系曲线,证明在绝热层一定厚度范围内,冷损失、蒸发量、蒸发率均随绝热层厚度呈双曲线关系,降低较快,此后保冷性能趋于稳定。计算表明实际工程中所采用的绝热层普遍偏厚,如实例中绝热层厚度减少53.3%,冷损失仅为最大冷损失的7.58%,仅比实际值增加3.82%;日蒸发率为0.04%,仅比实际值增大0.02%,表明实际工程中大型LNG储罐底部绝热层厚度优化大有空间。     

谈加工间低温空调设计中需注意的若干问题

阐述了在冷库加工间低温空调设计过程中需要特别注意的一些问题,为冷库加工间低温空调系统设计提供更加经济合理的设计思路和方法。     

Cryogenic valve pneumatically actuated by use of vapour pressure

A new concept of a cold actuator chamber is realized to avoid using cumbersome high-pressure helium gas cylinders in space for the cold valves in AMS-2 project [Cryogenic system for a large superconducting magnet in space, Part IV, alloy]. A good repeatability was shown in the first experiment with the cold valve opened and closed.     

NUMERICAL PREDICTION OF CONTAMINANT TRANSPORT AND INDOOR AIR QUALITY IN A VENTILATED OFFICE SPACE

A numerical study of air movement and contaminant transport is made to predict air flow patterns, ventilation performance and indoor air quality in a typical office space. Both conventional cooling and cold air jet cooling methods are investigated. The space heat load is from a hot wall that creates a plume. This plume either opposes or aids the flow of the jet depending on its location. The transient variation of room occupied zone average concentration is exponential after a change of the source strength equivalent to a change in the number of people in the room. The ventilation efficiency as well as the contaminant removal effectiveness of cold jet cooling is nearly the same as conventional cooling. Turnover time for cold air jet cooling is about 53% higher than conventional cooling when the hot plume aids the jet and 43% higher when it opposes the jet. The highest ventilation efficiency was η_v = 1.3 when the room is cooled with conventional temperature supply air, the plume opposed the jet and the contaminant source was located near the hot wall. The worst condition, η_v = 0.8, occurs when the air close to the pollutant source is stagnant. This happens for the room with an opposing plume, cold air jet cooling and a contamination source near the wall opposite the heated wall.     

Design and deformation behavior of high strength Fe–Mn–Al–Cr–C duplex steel

The influence of cold rolling reduction on microstructures and mechanical properties at room temperature of the duplex Fe–28Mn–7Al–5Cr–0.3C steel was investigated. In the Fe–28Mn–7Al alloy system, the duplex microstructure was obtained by lowering the carbon content to about 0.3 wt.%. The steel was austenito-ferritic with a low to moderate stacking fault energy. Two thermomechanical cycles were performed, which included cold rolling/annealing at 1100 °C, and cold rolling/annealing at 1100 °C/cold rolling/annealing at 1000 °C.The effects produced by cold rolling on the duplex steel were grain refinement and different strain-induced marks within the ferrite and austenite phases. They were easily observed within the austenite phase at a relatively smaller reduction than within the ferrite phase. Mechanical twinning plays a dominant role within the austenite phase during deformation at room temperature, resulting in extreme mechanical properties. No edge or longitudinal cracks were observed during cold rolling of the duplex steel.     

冷库地坪防冻架空层通风问题的研究

架空式地坪防冻是国内目前大中型多层冷库地坪防冻的主要方式。实际工程中发现,架空层内地面潮湿、积水,个别冷库架空层内常年潮湿的空气环境对冷库架空层结构产生了损害。本文根据实际工程建立计算模型,通过对不同地区和采用不同通风量进行计算,分析冷库地坪防冻架空层通风对架空层内温度和冷间地坪冷耗的影响。