共查询到20条相似文献,搜索用时 187 毫秒
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分别研究了溶剂法与SFE-CO2法从大蒜中萃取大蒜油的生产工艺,通过各项优化方法,确定了两种方法合理的工艺参数,通过比较大蒜油的产率,确定出两种方法的优缺点. 相似文献
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本文探讨了一种纺织品创新设计的新方法及其应用效果。针对创新设计灵感来自于经验与天分而起步于构思的特点,提出了方向思维创新设计方法,并将其归纳为向后、向前、向外、向内、侧向五种方向。结合机织物视觉效应创新设计中不同方向思维法的实例应用分析,总结了方向思维法的效果与应用要点。经论证方向思维法以常规设计思路的应用为参照,对纺织品创新设计效果明显且易于实施,在创新设计具有广泛性,并且可以是将两种及以上不同方向思维法的结合应用。 相似文献
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对采用汗渍试验仪给试样均匀施加负重下的干热试验、湿热试验和磨损涂层后的抗湿热粘连试验方法进行了考察,试验结果表明三种测定方法能测定出皮革面料抗粘连性的差异,并且一般情况下干热试验方法测定所得皮革面料抗粘连等级较另外两种方法的高。 相似文献
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全封闭热泵干燥系统冷凝温度对干燥能力的影响 总被引:2,自引:0,他引:2
本文针对全封闭热泵干燥系统不同冷凝温度下的干燥速度进行了分析,依据计算结果绘制出了不同风速时干燥速度随冷凝温度的变化曲线,提出了设计全封闭热泵干燥系统选取合适冷凝温度及风速的原则。 相似文献
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Nikolaos G. Stoforos João Noronha Marc Hendrickx Paul Tobback Dr. Kan‐lchi Hayakawa 《Critical reviews in food science and nutrition》1997,37(5):411-441
Kinetic data on thermal destruction of spoilage and quality factors coupled with the temperature history of a product during a heat sterilization cycle are the basic information needed for the evaluation and the design of thermal processes through a physical‐mathematical approach. A critical review on the available physical‐mathematical procedures used for thermal process calculations of in‐container processed foods is presented. The origin and the limitations of each method are discussed. The equations associated with each method, for internal product temperature predictions, are explicitly given. The relative performance of selected methods under identical processing conditions is illustrated. Several problems associated with thermal process calculations are discussed. 相似文献
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A bibliographic search yielded a set of empirical equations that constitute an easy method for the calculation of some thermophysical properties of both liquid water and ice I, properties that are involved in the modeling of thermal processes in the high-pressure domain, as required in the design of new high-pressure food processes. These properties, closely interrelated in their physical derivation and experimental measurement, are specific volume, specific isobaric heat capacity, thermal expansion coefficient, and isothermal compressibility coefficient. Where no single equation was found, an alternative method for calculation is proposed. Keeping in mind the intended applications and considering the availability of both experimental data and empirical equations, the limits for the set of equations where set in -40 to 120 degrees C and 0 to 500 MPa for liquid water and -30 to 0 degrees C and 0 to 210 MPa for ice I. The equations and methods selected for each property are described and their results analyzed. Their good agreement with many existing experimental data is discussed. In addition, the routines implemented for the calculation of these properties after the described equations are made available in the public domain. 相似文献
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为有效避免低热辐射环境中消防作业人员遭受热损伤,揭示消防服系统内复杂的热交换机制并由此指导产品设计与开发,由消防服系统传热理论出发,从消防服织物基本性能和服装的款式特征、人体的形态结构与活动状态、辐射热源的特征以及热湿耦合作用4个角度对当前的研究进展进行了回顾与讨论。基于对以往研究中存在的难点和瓶颈问题的分析,提炼出未来研究中值得探索的方向,包括:非均匀空气层的分布与模拟方法的升级、非稳态人体运动和环境风形成的气流场和速度场变化规律及其与传热的关系、耦合人体热调节模型拓展服装传热机制研究的内涵3个层面。 相似文献
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以北京首都机场扩建南区主体建筑T3航站楼热网管线为例,对热水管道直埋敷设方式进行了比较,总结出无补偿直埋敷设的设计方法采用应力分类法,计算难度大于有补偿直埋敷设,但无补偿直埋敷设的管道布置形式、施工难度、运行维护及经济性均优于有补偿直埋敷设。 相似文献
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SIMON Y. H O 《Journal of food science》2004,69(5):E224-E231
ABSTRACT: A 3-dimensional conjugate heat-transfer model for the analysis of freezing food products has been developed. The food-freezing process is a multi-medium, multi-phase, and transient heat-exchange phenomenon in connection with the cooling flow around the food items. The developed numerical model couples the energy equation with the Navier-Stokes equations outside the food items to simulate the velocity distribution around the food items and the heat flux across the food surfaces. The conjugate heat-transfer methodology and enthalpy method was used to solve the energy equation across the fluid-solid interface into the food item. The heat convection in the fluid and conduction in the foods are implicitly coupled to predict the heat-transfer rate and the enthalpy change during its freezing process. The conjugate heat-transfer model presented here is applicable to perform various heat-transfer calculations involved in the design of storage and refrigeration equipment and to estimate the process time required for freezing of foods. The article presents the mathematical model used, the outline of the numerical scheme, and the results of computations. The model-predicted results are compared with the experimental data available in the literature. Overall good agreement was obtained. 相似文献
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基于Pro/E的直齿圆柱齿轮参数化设计 总被引:6,自引:1,他引:5
齿轮是多参数驱动的标准机械零件,在Pro/E中由于没有机械零件的标准库,齿轮的设计步骤多、工作量大。本文利用Pro/E2001软件中自动化零件设计程序Program,开发了渐开线变位直齿圆柱齿轮的参数化造型设计方法,并采用该程序进行了实例设计,结果表明该程序可以实现直齿圆柱齿轮的快速设计。 相似文献