Mathematical simulation and experimental measurement of clothing surface temperature under different sized air gaps

The influence of air gap thickness on clothing surface temperature is analyzed by means of experimental and simulated methods. A three-dimensional body scanner is used to determine the air gap distribution between different-sized garments. The clothing surface temperature is measured by an infrared thermal camera to evaluate the heat transfer through air gap layer. The combination of two non-contact measuring techniques is a novel way to investigate the relationship between air gap thickness and clothing surface temperature. A mathematical model is set up to simulate the heat and moisture transfer from skin to environment by including the sensible and latent heat transfer through air gap layer under clothing, fabric layer and boundary air layer adjacent to the fabric. The established mathematical model is used to forecast the surface temperature and evaluate the heat transfer capacity of different sized garments.     

Effects of air gap entrapped in multilayer fabrics and moisture on thermal protective performance

Thermal protection of firefighter protective clothing is greatly influenced by the air gap entrapped and moisture in clothing. In this paper, the effects of air gap size and position on thermal protective performance exposed to 84 kW/m² heat source were investigated. Water was also added to thermal liner to understand the effect of air gap coupled with moisture on thermal protection. It was indicated that the TPP of fabrics system increased with the air gap size. The air gap position also greatly influenced the heat transfer during exposure to flash fire. Moisture added weakened the positive effect of air gap size when the air gap exists far from heat source, and almost eliminated the favorable effect of air gap position. However, when there is no air gap or small air gap between outer shell fabric and moisture barrier, moisture increased the thermal protection performance of multilayer fabrics system. The results obtained suggested that certain air gap entrapped in fabrics system and clothing microclimate could improve thermal protection, and the complicated effect of moisture should also be considered.     

云南小粒种咖啡热风干燥特性及其数学模型

以云南小粒种咖啡为原料,探究小粒种咖啡热风干燥特性及最佳数学模型,为咖啡热风干燥工艺提供参考。对小粒种咖啡湿豆进行热风干燥,用正交试验的方法研究其在不同热风温度、风速、铺装厚度和搅拌转速下的热风干燥特性,比较10种数学模型在热风干燥特性中的适用性。结果表明：热风风速在干燥实验中对传热传质有催进作用;搅拌可加快热传递提高热效率,减少干燥时间;铺装厚度主要影响干燥用时,铺装厚度与干燥速率变化成反比;咖啡干燥以降速干燥为主,无明显恒速干燥阶段,热风温度对热风干燥的干燥特性影响最大;对正交试验进行极差、方差分析可知,温度40℃,风速1 m/s,搅拌转速2 r/min为最优热风干燥方案,最佳数学模型为Logarithmic模型,热风温度、热风风速与搅拌转速3个因素对热风干燥总时长影响的极差值为19、6.67、5.5,3个因素在95%置信区间下P值为0.011、0.082、0.391。主次顺序为热风温度A>热风风速B>搅拌转速C;由评价指标R²、SSE、残差均方及对比实验数据与常用干燥模型进行非线性回归拟合分析,结果显示Logarithmic模型拟合度最好,其中R²为0.986444、SSE为0.021734、残差均方为0.002075。该数学模型可预测云南小粒种咖啡湿豆的热风干燥特性曲线,也为实际的生产与加工提供依据和参考。     

温敏核不育水稻植株温度的变化规律及与环境关系的模型

以温敏核不育水稻培矮64S为材料,采用10～15 cm水层灌溉处理和无水层对照,对植株温度及其与植株冠层小气候和灌溉水因子的关系作了分析。水稻植株温度与150 cm大气温度在数值和相位上均存在一定差异。8:00～20:00植株温度均明显低于大气温度,21:00～次日7:00植株温度与大气温度基本相同;日最高植株温度出现在13:00,比最高大气温度提前1 h,但日最低植株温度和最低大气温度均出现在6:00;植株温度的平均日较差比气温小。在同一高度上相比,晴天6:00～13:00植株温度比空气温度高,而且提前1 h升温,18:00～次日6:00则两者逐渐趋同或植株温度稍低;而在阴天,植株温度则全天一直高于空气温度,最高温度出现的时间也相同。植株温度白天的变化主要受太阳辐射的影响,天空状况（云量或日照时数）和风速都通过对辐射强度的调节和热量的交换而产生作用。植株温度夜间的变化主要受灌溉水的影响。在本试验条件下,日平均气温（Ta）29.6℃是灌溉水提高或降低植株温度的临界温度值,当Ta＞29.6℃时,灌溉水具有降低植株温度的作用,反之,灌溉水具有提高植株温度的作用。植株温度与水 气温差符合二次曲线关系。植株冠层在白天吸收或反射太阳辐射,夜间则阻挡热量散失,对调节植株温度具有明显的缓冲效应。通过相关分析和回归拟合,建立了两个可供实用的水稻植株温度的环境模型。     

Investigation on acoustic behavior and air permeability of struto nonwovens

This work deals with the study of acoustic performance of struto nonwovens and their relation to fabric air permeability. In order to achieve the objective of the research, sound absorption coefficient of struto nonwovens was determined via impedance tube method, the average value of sound absorption coefficient (α?) was calculated. Air permeability of struto nonwovens was examined by using FX3300 Textech Air Permeability Tester. Results showed that struto nonwoven exhibited good absorption ability at frequency bands 3000-6400 Hz while it was ineffective for frequency lower than 3000 Hz. Struto nonwovens with high GSM and fabric thickness showed better acoustic performance and lower air permeability. It was observed that α? was inversely proportional to air permeability, with correlation coefficient 0.95. It was concluded that air permeability can be used as a criterion of sound absorption behavior of struto nonwovens. A lower air permeability suggests a better sound absorption performance for struto nonwoven fabrics.     

NaN_3诱变小麦矮抗58后代变异的研究及SSR分析

为创造新的小麦种质,并探讨叠氮化钠对小麦诱变处理的适宜方法,采用种子处理同时鼓入空气、种子处理不鼓入空气、颖苞内滴加、生长点注射、穗茎注射5种方法诱变小麦矮抗58。其中种子处理同时鼓入空气方法处理的种子出苗率高,后代性状变异类型丰富,变异率高,是适合小麦诱变处理的一种切实可行的方法。通过多代选择选出了Y 58-1,Y 58-5,Y 58-7三个稳定的变异种质系;利用SSR分子标记检测＂矮抗58＂及其变异种质系的基因组DNA,引物xgwm 213,xgwm 219,xgwm 400,xgwm 428检测出了丰富的多态性片段,从分子水平上证明了叠氮化钠对矮抗58的诱变效果。     

Investigation and modeling of air permeability of Cotton/Polyester blended double layer interlock knitted fabrics

The aim of this study was to analyze and model the effect of knitting parameters on the air permeability of Cotton/Polyester double layer interlock knitted fabrics. Fabric samples of areal densities ranging from 315–488 g/m² were knitted using yarns of three different cotton/polyester blends, each of two different linear densities by systematically varying knitting loop lengths for achieving different cover factors. It was found that by changing the polyester content in the inner and outer fabric layer from 52 to 65 % in the double layer knitted fabric did not have statistically significant effect on the fabric air permeability. Air permeability sharply increased with increase in knitting loop length owing to decrease in fabric areal density. Decrease in yarn linear density (tex) resulted in increase in air permeability due to decrease in areal density as well as the fabric thickness. It was concluded that response surface regression modeling could adequately model the effect of knitting parameters on the double layer knitted fabric air permeability. The model was validated by unseen data set and it was found that the actual and predicted values were in good agreement with each other with less than 10 % absolute error. Sensitivity analysis was also performed to find out the relative contribution of each input parameter on the air permeability of the double layer interlock knitted fabrics.     

风道口流场对茶叶漂移轨迹及风选质量影响分析

为提高茶叶风选质量,以空气动力学为基础,将茶叶颗粒简化近似为球形颗粒;通过数值计算,研究不同重量的茶叶颗粒在不同的风道口流场(不同风速分布)作用下的漂移轨迹、水平漂移规律,以及风向角对茶叶风选质量的影响,并进行了相关试验验证。结果表明:在风选室相同情况下,风速按上小下大分布,茶叶颗粒群的有效漂移距离大于其他风速分布方案;风向角α=16.3°,风速分布系数β=0.17为最佳风口流场参数组。本研究为优化设计茶叶风选机提供了理论基础。     

Study of kernel structure of high-amylose and wild-type rice by X-ray microtomography and SEM

Rice kernels of a transgenic high-amylose rice line and its wild type were examined by a high-resolution X-ray microtomography (XMT) and an environmental scanning electron microscope. Two-dimensional (2-D) cross-sectional images and 3-D objects from XMT were reconstructed and analyzed to elucidate their structural features. The lack of two isoforms of starch branching enzyme, termed SBEI and SBEIIb in high-amylose rice (HAR), resulted in a distinctly different grain inner density than wild-type rice (WTR). HAR had smaller, elongated starch granules with air spaces inside the kernels resulting in an opaque grain, whereas WTR had a tight endosperm with little air space and polygonal starch granules. XMT allowed a full 3-D characterization of the rice kernel structure and revealed that air space distribution was not uniform in the HAR kernel.     

Air pollution injury of potato in Michigan

A disorder of Michigan potatoes tentatively called speckle leaf is associated, in part, with air pollution injury. The disease is characterized by reduced yields following early vine maturity, premature vine death, and yellowing of the lower leaves. Necrotic spots developed on the upper surface of leaves, followed by bronzing, and upward leaf rolling. Severely affected leaves became chlorotic and remained attached to the stem. Potato plants were grown in two plastic houses through which was blown either ambient field air or ambient air filtered through activated charcoal. Plants grown in the plastic house receiving ambient air developed symptoms similar to nearby field plants. Plants grew normally in filtered ambient air and remained free of speckle leaf and air pollution injury symptoms. The potato varieties Haig, Norchip, and Superior were most sensitive, Sebago was intermediate, and Kennebec and Katahdin were most tolerant. Tobacco plants in ambient non-filtered air developed symptoms typical of ozone injury. Bean leaves became bronzed with brown necrotic flecks on both surfaces, and severely affected leaves dropped. Neither tobacco nor bean was affected in the filtered air.     

Impact of sampling and storage technique,and duration of storage,on the composition of fresh grass when analysed using near‐infrared reflectance spectroscopy

The objective of this study was to examine the effect of sampling technique (pluck or cut), storage duration (immediate analysis, 24‐h or 48‐h), storage temperature (ambient or chilled) and storage conditions (air present, air excluded or breathable) on the composition of fresh grass sampled from a sward managed to simulate grazing. Treatments were repeated across four sampling dates, with grass samples stored in grip seal bags prior to analysis using near‐infrared reflectance spectroscopy. Grass sampled by ‘pluck’ had a higher crude protein and ME content, and a lower acid detergent fibre (ADF) content, compared to that sampled by ‘cut’. Grass stored for 48 h had a lower water soluble carbohydrate (WSC) and ME content and a higher ADF content than for immediate analysis. Samples stored for 24 h did not differ from immediate analysis. Grass stored at ambient temperature had a lower WSC and ME content compared to immediate analysis. Grass stored under ‘breathable’ conditions had a lower ME content and higher ADF content than immediate analysis or samples stored with air present or air excluded. It is recommended that grass for analysis should be sampled by cutting, stored chilled (4°C) in a sealed bag to minimize exposure to oxygen and analysed within 24 h of harvest.     

气流对做青环境及乌龙茶品质形成的影响

模拟正压全面送风空调做青环境和密闭空调做青环境,对做青过程两种环境的气温、气湿、气质等参数以及青叶呼吸速率进行在线测定,探明气流对做青环境、青叶生理变化及毛茶品质的影响。实验表明,两种气流条件下的叶层空气湿度、CO2含量和青叶呼吸速率存在极显著差异。气流控制的空调做青环境的毛茶品质优于密闭空调做青环境的毛茶品质。     

Effect of opening roller speed, drums speed difference and suction air pressure on properties of open-end friction spun polyester and acrylic yarns

The present paper is concerned with the influence of opening roller speed, drum speed difference and suction air pressure on properties of polyester and acrylic open-end friction spun yarns. The results shows that the opening roller speed and the suction air pressure have considerable influence on the characteristics of polyester and acrylic open-end friction spun yarns. In case of polyester yarns the unevenness, imperfection and hairiness decreases and the yarn tenacity increases with the increase in opening roller speed and suction air pressure. However for acrylic yarns the unevenness and imperfections decreases and tenacity increases with the increase in opening roller speed and suction air pressure.     

低氧热泵干燥技术的国内外研究概况

低氧热泵干燥技术是采用其他气体,如二氧化碳和氮气等代替常规空气作干燥介质,密闭循环系统进行低氧环境的气调干燥加工。该技术提升干燥品质,节约能耗,提高干燥效率,有效解决氧敏性、热敏性物质的干制问题,有广阔的应用前景。本文介绍低氧热泵干燥技术中不同气体作干燥介质的物性研究、对干燥品质特性的影响、相关装置的研制等方面的国内外研究概况。     

Predicting the date of harvest of vining peas by means of air and soil temperature sums and node countings

Predictions of the date of harvest of vining peas (Pisum sativum L.) were performed by means of statistical models. Simple models based on sowing-to-harvest prediction criteria and two-component models based on a combination of sowing-to-emergence and emergence-to-harvest prediction criteria were applied. The criteria used were number of days, and soil and air temperature sums, with base temperature in the range 2.6–3.8°C and 3.0–6.0°C, respectively.The best predictions of the harvest date were obtained with two-component models, and sowing-to-emergence predictions criteria based on soil temperature were better than others examined. Among two-component models, the smallest error of prediction-2.4 days-was obtained with the model using sowing-to-emergence soil temperature sums with base temperature 3.0°C, and emergence-to-harvest number of days as prediction criteria. The prediction model traditionally used in practice applies sowing-to-harvest air temperature sums with base temperature 4.5°C as prediction criterion, and the error of prediction of this model was 4.3 days.Close linear relationships were found between number of nodes and air temperature sums accumulated from sowing or emergence. In consequence, the number of nodes is a reliable indicator of the actual air temperature sum status of the crop.Some practical aspects of applying two-component models and node counting for predicting the date of harvest of vining peas are discussed.     

Open-Top Chambers with Solar-Heated Air Introduction Tunnels for the High-Temperature Treatment of Paddy Fields

Abstract

The quality of rice grain has been deteriorating as a result of the high temperature during the ripening stage caused by global warming. Easy and effective methods of high-temperature treatment are essential for the analysis of high-temperature tolerance and to screen for tolerant strains. We have improved the open-top chamber (OTC) by adding a solar-heated air introduction tunnel (SAT). The air is warmed by solar radiation as it passes through the tunnel and then flows into the OTC. The increase in temperature in the OTC-SAT was powered by solar radiation. Thereby, the temperature in OTC-SAT rose during the day according to the distance from the air intake (the nearer, the higher). A more uniform increase in temperature of approximately 1.2°C in the daytime was achieved by attaching a sloping wall and funnel-shaped air exhaust tunnel to the OTC-SAT to improve the air flow. The area of the high-temperature treatment was easily increased by increasing the width of the OTC-SAT; this finding might be useful for screening a large number of strains. The increase in the percentage of chalky grains by the use of OTC-SAT was similar to that obtained with the other treatment methods; the OTC-SAT will thus be useful for investigating high-temperature tolerance during the ripening stage, particularly in areas where the wind direction is stable. The use of an OTC with a funnel-shaped tunnel on both the air entrance and the air exit sides might be useful in areas where the wind direction is often reversed.     

The influence of some soil physical properties on potato yields and grade distribution

Yields of U. S. No. 1 potatoes and numbers of deformed tubers were significantly correlated with air permeability near the surface and soil bulk densities down to 8 inches. Yields of No. 1 grade were correlated positively with soil air permeability and negatively with soil bulk density, whereas for deformed tuber production the correlations were the reverse. Total tuber production had a low correlation with soil factors because of the opposing responses of U. S. No. 1’s and deformed tubers. In a multiple-regression analysis, large variations in total yield, grade distribution, emergence rate, and final stand were accounted for by considering soil bulk density, soil strength, and air permeability. Production of quality tubers was closely associated with mechanical-impedance factors in the immediate zone of tuber development. Yields of U. S. No. 1’s were reduced 35% by a severe soil-compaction treatment in the beds.     

Comparison of regression and adaptive neuro-fuzzy models for predicting the compressed air consumption in air-jet weaving

The aim of this study was to compare the response surface regression and adaptive neuro-fuzzy models for predicting the compressed air consumption in air jet weaving. The prediction models are based on the experimental data of 100 samples comprising weft yarn count, fabric width, loom speed and reed count as input variables and compressed air consumption as output/response variable. The models quantitatively characterize the linear and quadratic relationships as well as interactions between the input and output variables exhibiting very good prediction ability and accuracy, with ANFIS model being slightly better in performance than the regression model. The models could be used for estimating the compressed air consumption, identifying air leakages and production planning in a weaving mill.     

Heat and mass transfer studies of palm kernel cake (PKC) in fluidized bed fermenter

Solid state fermentation (SSF) which involves the growth of microorganism on moist solid substrates in the absence of free flowing water, has gained renewed attention over submerged fermentation for specific applications. During the SSF process in fermenter, there are three main engineering problems encountered such as the removal of metabolic heat from the substrate, diffusion of O₂ and moisture through the substrate, and heterogeneity of the substrate and inoculum. A fluidized bed fermenter in which the particles move independently like a fluid was proposed to conduct the study. Throughout the study, rapid heat transfer from PKC to air was experimentally observed within the first 150 s with a temperature drop of 30 °C. This indicated that the excellent heat transfer between palm kernel cake and air allows solid state fermentation of PKC without accumulation of metabolic heat in the fermenter. Apart from heat removal, water adsorption study on PKC from air to bed was carried out. It showed that the increase of adsorbed water in PKC was proportional to air relative humidity and inversely proportional to superficial air velocity. The maximum moisture content adsorbed by PKC under fluidization conditions was around 10% (on dry basis). Finally, mathematical models for heat and mass transfer were proposed which can predict the experimental data quite satisfactorily.     

Evaluation of seed dressing dust dispersion from maize sowing machines

The present study analysed the constructive and operative parameters of pneumatic seeders and researched and assessed possible technical solutions for limiting the unwanted dispersion of dust from seed dressing during sowing of maize seeds. Tests were made on several maize pneumatic seeder models. The air flow rates and the air velocities at the fan outlet were assessed, the sizes of the areas contaminated with the material from the maize seeds was evaluated and the air velocities along the contour of the sowing machines were measured. Results showed that by decreasing the fan air flow rate by 30% it was possible to consistently reduce the size of the area contaminated by seed dressing dust while maintaining a good quality of seeding. They also showed that the technical solutions proposed by the seeder manufacturers reduced the environmental contamination with the pesticide-containing dust by more than 90%.