相变蓄冷技术在食品冷链运输中的研究进展

目的 概述相变蓄冷技术在食品冷链运输中的研究进展,为冷链运输发展提供一定的研究思路。方法 综述相变蓄冷技术在蓄冷式冷藏车、蓄冷保温箱及其他冷链运输设备中的应用,主要对其相变蓄冷材料、蓄冷技术与保温材料的结合、运输过程内部温度分布的影响因素及其新型的运输方式进行论述。结果 相变蓄冷技术在食品冷链的各种运输设备中都有广泛的应用领域和较大的发展空间。结论 相变蓄冷技术是提高能源利用效率的有效手段,在冷链运输系统中具有广阔的应用前景。相变蓄冷材料、保温材料以及运输过程中温度稳定分布的研究及多温共配技术是今后的研究方向。     

相变蓄冷技术在食品冷链中的应用与进展

相变蓄冷技术在食品冷链领域应用中有着广泛的前景。本文综述了相变冷藏技术在食品冷链的近期发展现状,介绍了相变蓄冷技术应用于蓄冷板冷藏库、蓄冷板冷藏车、冷藏保温箱等冷链不同领域的研究进展。本文也呈现了使用计算应用流体动力学(CFD)数值模拟软件ANSYS描述蓄冷板和蓄冷板冷藏车蓄冷过程的温度分布。结果表明,当进口温度不变,蓄冷量随换热流体流速的增加而增加。相变蓄冷技术的应用,在冷藏运输设备领域有巨大的发展前景。根据国内外相变蓄冷技术的研究情况,本文提出了相变蓄冷技术需要解决的问题,为今后进一步研究提供了一定的参考依据。     

PCM蓄冷板式冷藏车温度场数值模拟研究

本文以冷藏车为研究对象,建立了冷藏车箱体的物理模型和数学模型,将已研制的新型相变材料(HWY-1)运用到蓄冷式冷藏车内,并利用ANSYS-FLUENT对冷藏车车厢内的温度场进行了数值模拟。通过对冷藏车车厢内有蓄冷板和无蓄冷板温度场的模拟分析,研究车厢内不同横截面的温度。结果表明,在有蓄冷板的条件下距车厢底部500 mm、1000mm、1500 mm、1800 mm处的温度点,7 h后与初始温度相比分别下降了5.7%、24.5%、51.9%、76.3%,而在无蓄冷板的条件下,这些温度测点都有不同度的提高。因此,应用PCM蓄冷板式冷藏车车厢内的温度可以保持长时间低温,符合冷藏运输过程中实际需求。     

蓄冷保温冷藏车

本文详细阐述了影响蓄冷保温冷藏车性能的一些因素及其相互关系。通过与机械制冷冷藏车比较，指出在冷藏温度要求较低或恒定的短程冷藏运输中，蓄冷保温冷藏车是一种适宜的运输工具，值得予以重视推广。     

一种新型冷藏车箱体模型的设计与实验验证

设计了一种具有蓄冷功能的冷藏车箱体模型。为了评估此箱体的保温功能,首先对其传热效果进行了三维数值模拟, 然后以上海青为例对其进行了实验验证。结果表明,此冷藏箱体可以有效地减缓冷藏运输过程中上海青的温度回升速率,说明在冷藏车的箱体中添加复合相变材料可以有效提高其保冷效果。     

蓄冷技术在冷链物流中的研究进展

对比无机相变材料、有机相变材料及复合相变材料的优缺点,分析保温材料在蓄冷保温箱和冷库等低温仓储设备中的应用情况,阐述蓄冷技术应用于冷库与低温仓储等领域的研究进展。蓄冷材料性能的提升、冷藏运输装备温度场的均匀性、保温材料的优化、低温仓储的节能性等是今后蓄冷技术在冷链物流中应用的研究重点。     

有机相变蓄冷材料的研究进展

本文概述了有机相变蓄冷材料和有机-无机复合相变蓄冷材料的研究进展,探讨了采用公式指导低共融物相变蓄冷材料配比和提高有机相变材料导热能力的方法,介绍了相变材料在太阳能利用、电力的峰谷平衡、空调节能与冷藏运输等方面的应用研究。指出相变材料的性能特性、相变机理、传热理论模型及复合技术是有机相变蓄冷材料研究的重点内容,有机复合相变蓄冷材料是今后有机相变材料的重点发展方向。     

蓄冷型运输保温箱在冷链中的应用

本文综述了蓄冷型运输保温箱在冷链中的应用。与传统的冷藏车对照分析,蓄冷型运输保温箱具有灵活性、环保性、经济性、安全性、可控性等特点。文中分析了蓄冷型运输保温箱的发展现状及不足。对现有保温箱使用的相变蓄冷剂和保温材料进行了分析,提出了使用真空绝热板作为保温材料的可行性。蓄冷型运输保温箱已在医疗领域得到广泛的应用,现在又是冷藏运输发展的方向之一。     

有机相变蓄冷复合材料的研究

研制了一种新型三元复合相变蓄冷材料.利用差示扫描量热仪测量物质的性能,测得相变材料相变温度为-14℃,相变潜热为172J/g.主要成分是丙三醇、乙酸钠和水,原材料价格便宜且易购得,可以大规模应用于冷库冷藏、低温物流等领域.     

蓄冷技术在食品冷链物流中的研究进展

目的 研究蓄冷技术在食品冷链物流中的应用进展, 提出仍需解决的问题。方法 综述了蓄冷技术应用于蓄冷板冷藏车、 蓄冷型保温运输箱、 控温包装、 低温仓储冷库等领域的研究进展, 同时对食品冷链用蓄冷剂的相变温度、 相变潜热、 用量等相关参数及其与微胶囊等技术的复合研究进行了论述。结果 蓄冷技术在食品冷链的各环节中都具有广泛的应用背景和节能潜力。结论 蓄冷材料本身、 蓄冷板冷藏车、 蓄冷式多温共配技术等是今后蓄冷技术在食品冷链物流中应用的研究方向。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to