人体局部皮肤的气流敏感性及其影响因素

为探究人体不同体段皮肤对气流的敏感性差异及影响因素,测试了人体前胸、后背上、后背下、大腿前和大腿后5个体段在接受低于皮肤温度5 ℃、等于皮肤温度和高于皮肤温度5 ℃的气流刺激时,各体段的局部皮肤温度变化率以及主观气流强度感觉,应用韦伯分数分析各体段对气流的敏感性差异。结果表明:通风温度对人体气流敏感性有显著影响,当通风温度与局部皮肤温度相等时,皮肤气流敏感性最差,说明温度感受器对皮肤气流感知发挥重要作用;后背上部与大腿前部对热气流最敏感,而后背下部与大腿后部对冷气流最敏感,但各部位之间并未发现显著的统计学差异。     

Convection and radiation combined surface heat transfer coefficient in baking ovens

The combined surface heat transfer coefficient is a determining parameter of convective baking process time and efficiency, as well as the resulting food product quality. By this study, the combined surface heat transfer coefficient term was determined at the convective oven temperature range of 70–220 °C, with fan (turbo) and without fan (static oven) applications. The methods of “Lumped Capacity” and “Time–Temperature Matching” were used. Both methods utilize the time–temperature data at a fixed position of a definite material, during unsteady state heating up period inside the convective oven. The increase in oven temperature and the fan application in the oven derived higher calculated values of surface heat transfer coefficients. Good agreement was observed between both methods and the literature values. The given methods are applicable to other oven types and heating modes.     

BF-12型卫生纸机气罩空气平衡分析实践

气罩通风系统的空气平衡状况对扬克纸机的热效率有重要的影响。本研究结合企业实际情况,对两台典型的BF-12型纸机(PM1及PM2)进行了测量及分析。研究结果发现:PM1气罩空气平衡率过低,应该减少通风系统的抽风量;PM2气罩干区的空气平衡率过高,应该减少通风系统的送风量。     

德国青泽Z360细纱长车工艺排风节能改造

根据德国青泽Z360机台的结构状况,对机台进行了节能改造,取消原10 kW的工艺排风风机,改用2台2.2 kW的风机分别安装在机台的车头和车尾,工艺排风也由原来的从车头排改为从两头排,并在车尾处增加一只吸风箱,使得工艺排风的负压由原来的740~1 100 Pa改善为900~1 000 Pa,缩小了车头、车尾负压的差异,使其基本相同。改造后,降低了吸棉功率,节约了耗电量,成纱指标也较为一致,提高了产品质量。     

Effect of oven temperature profile and different baking conditions on final cake quality

This study discusses the effect of airflow on oven temperature profiles, the internal cake temperature and the final cake quality. It was found that the presence of airflow reduced the oscillation in the oven temperature profile from 12.98–30.27% to 3.17–4.02%. The bottom of the oven chamber experienced the greatest reduction in temperature oscillation in the presence of airflow. During the second stage of baking with airflow, the heating rate was increased from 5.07 to 7.52 °C min^?1 and 8.35 °C min^?1 to the increase of the baking temperature from 160 to 170 °C and 180 °C, respectively. The cake volume expansion rate was also increased 5–10% during second stage when baking with airflow condition. The cakes baked in the presence of airflow had a more porous crumb texture and lower moisture content compared to the cakes baked without airflow.     

利用空气幕提高抽油烟机抽吸效率

油烟是室内空气的主要污染源,控制其扩散是抽油烟机实现高效率捕集油烟的有救手段.采用在集气罩上加装空气幕的技术措施,能够阻止油烟蔓延,保持室内外压力平衡.从提高空气射流的动力性能和阻断能力着手,开发稳定性和封闭性较好的空气幕应用于抽油烟机,不仅提高了工作效率,而且节能效果显著.     

FHG型细纱吸棉风机的设计及节能效果

探讨FHG型细纱吸棉风机的节能效果.在保持传统细纱机吸棉风机基本结构特点不变的基础上,根据三元流场理论计算分析模拟结果,对传统细纱机吸棉风机的叶轮、叶片形状及出口角度、前盘、蜗壳构件等进行了改进设计.通过对风机性能测试及运行试验的应用研究,认为:FHG型细纱吸棉风机运行效率较高、实耗功率较低,在节电40%的情况下,完全能够满足细纱机断头吸棉的要求.     

酸雾风机系统的修复

酸雾风机系统损坏造成酸洗车间挥发性和腐蚀性气体难以及时排出。造成损坏的原因有:酸洗工艺由硫酸改为盐酸,排风机底部钢结构支架断裂,管道系统阻力较高。改进的措施:在排风机进口前增加喷淋除酸装置,风机叶轮表面采用玻璃钢防腐处理,钢结构支架用钢板或槽钢加固,调整橡胶减振垫的数量和安装位置,适当降低离心风机的转速。对系统风量和管道阻力进行计算校核,校核结果满足使用要求。生产使用表明,修复后的酸雾风机系统满足酸洗生产的要求。     

国产沙门氏菌免疫磁珠的制备及其应用

目的优化免疫磁珠制备条件,获得捕获性能高、成本低的国产沙门氏菌免疫磁珠,为国产沙门氏菌免疫磁珠的产业化制备奠定基础。方法采用亚微米级羧基磁珠及沙门氏菌多克隆抗体,利用碳二亚胺缩合法制备2 mg级免疫磁珠。以目标菌捕获率、磁珠表面抗体偶联率为评价指标,对4种粒径(100、300、500、1000 nm)的磁珠原材料进行筛选;以目标菌捕获率、磁珠表面抗体偶联率、免疫磁珠表面FITC荧光强度为评价指标,对磁珠与抗体不同的投料比(100:1、100:1.5、100:2、100:2.5、100:3)进行优化;同时,对国产沙门氏菌免疫磁珠与进口免疫磁珠(Dynalbeads~?沙门氏菌免疫磁珠、Bac Trace~?沙门氏菌免疫磁珠)的性能进行比较分析,考察了捕获率、免疫磁珠与目标菌的结合情况、特异性捕获能力等,并在实际样品中进行了应用检测。结果以粒径为300 nm的磁珠为原材料制备的免疫磁珠对浓度为10~2 CFU/mL的目标菌的捕获率为99%、抗体偶联率为34.64%,明显高于其他粒径的免疫磁珠;当投料比为100:2(磁珠:抗体)时,制备的免疫磁珠对浓度为10~2 CFU/m L的目标菌的捕获率为100%,偶联率为52.34%,优于其他投料比;针对不同浓度的鼠伤寒沙门氏菌(10~0~10~6 CFU/mL),国产免疫磁珠的捕获率高于进口免疫磁珠(国产:83%~100%;Dynalbeads~?:57%~74%;Bac Trace~?:9%~40%);在25 mL牛奶中添加(11.9±3.7)CFU鼠伤寒沙门氏标准菌株,国产沙门氏菌免疫磁珠的检出率高于进口免疫磁珠(国产:100%;Dynalbeads~?:70%;Bac Trace~?:40%)。结论优化了制备条件后所制备的国产沙门氏菌免疫磁珠的捕获能力强、价格低、能够实现大体积实际样品中痕量目标菌的100%检出,具有广阔的应用前景,本研究为沙门氏菌免疫磁珠的国产化应用提供了科学数据。     

自堆积式螺旋速冻机流场数值模拟

研究了在入口风速不变的条件下,通过改进结构和改变冻品参数,增大流场气流平均速度,达到降低装置能耗、提高冻结效率的目的。建立二维紊流模型,采用SIMPLE算法,对未放冻品原有结构的流场、开孔和增设隔板后的流场、食品不同摆放密度的流场以及不同食品高度的流场进行模拟计算分析,结果表明:网带的对螺旋塔内流场的平均速度影响小。增设隔板和开孔有利于提高流场内气流的平均速度,增加热交换的充分性。冻品摆放密度增加需要综合考虑气流平均速度、压力、和风机功率等因素。冻品高度在满足不超过孔的位置高度下,增高能增加气流平均速度。     

Nanostructured sorbents for capture of cadmium species in combustion environments

The pathways of cadmium species to form a submicrometer-sized aerosol in a combustion system exhaust were established. Cadmium oxide was the predominant species formed in the experiments and resulted in particles of a mean size of 26-63 nm with number concentrations in the range of 2-8 x 10(6) cm(-3). Two different nanostructured sorbents, a solid montmorillonite (MMT) and an in situ generated agglomerated silica, were used for capture of the cadmium species. The MMT sorbent was not stable at 1000 degrees C, and structural changes resulted. MMT did not suppress nucleation of cadmium species and partially captured it by weak physisorption as established by the leachability tests. In contrast, the in situ generated silica nanostructured agglomerates had a high surface area, suppressed nucleation of cadmium species vapors, and chemisorbed them effectively resulting in a firm binding, as compared to the MMT sorbent. There is an optimal temperature-time relationship at which the capture process is expected to be most effective. The leaching efficiency under these conditions was less than 3.2%. The nanostructured silica agglomerate size can be tuned for effective capture in existing particle control devices.     

Evaluation of baking performance by means of mid-infrared imaging

The present work aims to validate mid-infrared imaging as a promising method for evaluating oven systems. Therefore, a novel approach by analyzing mid-infrared radiation patterns captured by a thermal camera and subsequent image processing was developed. A thermal camera was adapted to two different oven systems: a standard electric deck oven and a novel gas-fired baking oven with integrated volumetric ceramic burners (VCBs). The baked goods were analyzed and key indicators describing the final product quality were determined. Specific volume, surface browning and mid-infrared image processing demonstrated a comparable performance of both oven systems. Furthermore, the determined surface heat homogeneity of the items to be baked was 0.65 ± 0.05 (–) for the electronic oven and 0.70 ± 0.03 (–) for the VCB oven. The proposed approach proved its fundamental qualification for comparing and evaluating different oven systems.     

Performance Evaluation of Top-Spray Fluidized Bed Coating for Healthy Coated Rice Production

Coating with top-spray fluidized bed at inappropriate operating condition not only provides low product quality but also leads to low coating efficiency and improper energy consumption. The objective of this study was therefore to study the effects of superficial air velocity (Vf), atomization air pressure (Ap), and recycled exhaust air (Ra) on the performance of top-spray fluidized bed coating (TSFBC) in terms of product quality, coating efficiency (CE), and energy consumption for producing turmeric extract coated rice (TECR). The experimental results showed that the operation of TSFBC without Ra provided the final moisture content (MC) of TECR lower than 12 % (wet basis (w.b.)) for all Vf’s and Ap’s. The lowering final MC of TECR below 11.8 % (w.b.) led to the fissure of all TECR kernels. The Ra with 80 % could significantly reduce the number of fissured kernels and the energy consumption of electric heater by 41.7–46.5 %. The operation of TSFBC at low Vf, i.e., 2 m/s, resulted in high number of uncoated white rice kernels (UCWR) for all Ap’s and Ra. When the Vf was increased to 2.5 or 3 m/s, the number of UCWR was significantly reduced and the value of CE was higher than that at 2 m/s. At such both velocities, the Ap and Ra insignificantly affected the CE but the Ra slightly affected the number of UCWR.     

两种干燥方式对鸡油菌氨基酸组成及评价的影响

为探究烘干（干燥箱60℃ 16 h）、自然晾干（在室温（25±2）℃、湿度38%±1%、东南三级风、晒干5 d）两种干燥方式对西藏林芝野生鸡油菌样品19种氨基酸的组成及评价的影响。采用2,4-二硝基氟苯衍生高效液相法检测18种氨基酸,色氨酸检测采用比色法。结果表明,林芝鸡油菌的蛋白质较为丰富,烘干（22.52%）较自然晾干（31.13%）有损失;必需氨基酸占总氨基酸的比值（自然晾干28.27%、烘干28.10%）低于理想蛋白模式;有较高的鲜味氨基酸（F/T为自然晾干37.38%、烘干32.02%）和药用氨基酸（D/T为自然晾干57.01%、烘干54.78%）;谷氨酸、天冬氨酸、精氨酸、丝氨酸、丙氨酸含量相对较高,烘干较自然晾干有减少;从3种氨基酸评价模式（WHO/FAO氨基酸模式成人需要量、11~18岁需要量和鸡蛋白）看,两种样品的第一限制性氨基酸均为赖氨酸,烘干样品的化学评分（CS）和氨基酸评分（AAS）均高于自然晾干样品,含硫氨基酸（蛋氨酸＋半胱氨酸）的评分最高,两份样品EAAI均低于鸡蛋白模式。可采用烘干方式干燥鸡油菌以提高干燥效率。     

电机弱磁节能技术在干燥风机上的应用

食品干燥加工设备多选用高效离心风机,此类风机的效率已经处于一个较高的水平线上,难以再大幅度提高风机本身的效率。文章阐述的最有效的风机节能方案就是利用现有的变频调速器来调节流量、风量,在此类节能的基础上,再根据风机特性曲线,利用电机弱磁技术实现比变频器的节能再提高1%～10%,实现食品干燥设备最大化提高效率,本系统阐述的方案符合中国资源节约型、环境友好型和谐社会发展的需要。     

数值模拟技术预测风机两种摆放方式对冷库堆垛货物的影响

为研究不同风机摆放方式对满载货物冷库气流分布以及堆垛货物温度分布的影响,以实际参观走访的中型冷库(24.3m×21.6m×7.2m)为蓝本,利用多孔介质模型并运用ergun方程对货物侧进行建模,分别建立风机下吹型和对吹型冷库模型,使用fluent软件对模型进行稳态模拟,对比分析两种风机摆放方式对该库及堆垛货物内部气流组织分布的影响。结果发现:下吹风冷库气流在货物区域温度和流速分布均匀,对吹风式冷库在货物区域温度分布并不均匀,气流风机射流末端货物区域存在大片高温区,因而可以得出:在所讨论的冷库中,风机下吹风摆放方式优于冷库风机对吹风摆放方式。     

染色织物潮态定形色差的产生原因

染色织物潮态定形时产生色差的原因,包括轧车压力不匀,烘箱循环风机转速不匀,烘箱结构使织物水分蒸发速率过快,染料和整理剂选择不当等,应针对实际情况采取相应的解决措施.     

管道主动噪声控制系统

根据声场固有特性．提出基于相位自动跟踪（PAT）的前馈控制系统。并应用于管道降噪试验研究。结果表明该算法在单频管道噪声消除中稳定有效。为了解决更复杂的噪声,本文基于FmLMS算法进行了主动消声仿真研究,结果表明FIRLMS算法处理复杂管道噪声的有效性,仿真中对参数的提取也为以后高效实施做了准备。图11参12     

Effects of Frozen Storage and Cooking on Lipid Oxidation in Chicken Meat

Fresh chicken breast and leg meat samples, which were frozen for 3 months or 6 months at −18°C, were cooked in microwave and convection ovens and then tested for levels of lipid oxidation. After 6 months storage, malonaldehyde in fat from meat samples, as measured by a TBA assay, modified to avoid sample autoxidation, increased 2.5 fold, while the fluorescence excitation (360 nm) and emission (440 nm) spectra increased an average of 34%. Fat from meat cooked in a convection oven averaged 83% higher malonaldehyde concentration and 21% higher fluorescence compared to levels before cooking. Levels of lipid oxidation products in fat from chicken breast and leg meat were not significantly different in microwave compared to convection oven cooking; but certain secondary fluorescent products were higher in meats cooked by convection oven.     

烤房不同通风方式对有关烘烤参数的影响

机械辅助排风烤房比自然通风烤房进风口进风速度明显增强,烟叶失水速度明显增大。自然通风状态下,进风口进风速度随烤房内温度的升高而近直线增大,烟叶的失水速度也明显提高,而在具有一定排风强度的机械排风状态下,进风口进风速度受烤房内温度变化的影响很小,烟叶失水的速度虽随温度的升高而加大,但变化的幅度比自然通风状态下要小。恒定供热情况下,烤房内温度、烟叶失水速度随通风方式的不同而改变,且具有一定的规律性。机械辅助排风有利于提高烟叶的烘烤质量。