我国水溶性维纶无捻纱线发展前景分析

水溶性维纶无捻纱线是一种用途广泛的纺织原料,由于该产品具有普通维纶的强度和模量,耐腐蚀、耐酸碱及干热稳定性好,最大特点是可溶于一定温度的水中。文章对水溶性维纶无捻纱线的生产特点、地域分布及替代品情况进行了分析,并预测其发展趋势前景。     

棉/水溶性维纶无捻纱线及其织物的退维分析

退维时间和温度是棉/水溶性维纶无捻纱线生产工艺的关键性技术条件,采用称重法分析了环锭纺棉/水溶性维纶无捻纱线及其不同线密度无捻纱线平纹、透孔组织织物的退维时间和温度。结果表明,棉/水溶性维纶无捻纱线与水分子接触较充分退维迅速,40℃水溶性维纶在75℃恒温水溶液里,5 min便可完成退维纶;而其机织物因交织点紧密退维时间较长,在85℃恒温水溶液里完全退维要35 min。同时纱线线密度小,其织物的退维时间相对较少。     

不同混纺比水溶性维纶纱线的性能测试与分析

分析对比不同混纺比水溶性维纶混纺纱线的性能指标。对3种混纺比的29tex和14.5tex棉水溶性维纶混纺纱性能指标进行了测试,并与同号纯棉纱进行了对比。结果表明:C/V 65/35纱各项指标均较好,C/V 85/15纱指标较差,纯棉纱断裂伸长率和耐磨次数较低。认为:应根据成品质量和风格要求,在成本许可的情况下,适当增加水溶性维纶的混纺比,有利于提高水溶性维纶混纺纱的织造性能。     

无捻棉纱机织物性能分析

介绍了在经简单改进的环锭细纱机上,利用短纤水溶性维纶纤维与棉纤维纺制无捻棉纱的工艺流程,分析了退维后无捻棉纱的外观特点及其性能。利用所纺制的纱线织造出了无捻平纹机织物,并分析了无捻纱织物的性能。     

水溶性维纶及其产品开发

文章叙述了水溶性维纶的基本性状,及其开发现状,介绍了以水溶性维纶作载体纱的纺纱方法及其产品特点。以典型的6类产品为例,阐述了如何发挥水溶性维纶的水溶特点来开发新产品,指明了这些产品的用途和发展方向。     

色纺溶变技术及产品探讨

探讨色纺溶变技术产品的性能特点及生产技术要点。将水溶性维纶与其他纤维混纺、均匀分布于纱线服饰中,通过维纶的溶解消失来实现服饰色彩、结构的变异。主要过程包括可变元素选择、分布方法、控制变换等几个环节。除颜色深浅变化的基本类产品外,与花式纺纱技术相结合,可以实现更加丰富多彩的色纺溶变产品。指出色纺溶变技术的要点是合理选配维纶原料,采用色纺精密混和技术,水溶性维纶不能作为纱线服饰的主体骨架,织物后处理工艺应避免高温给湿,防止意外溶变等。最终生产出的色纺溶变技术产品性能可满足要求。     

水溶性维纶纯纺纱生产实践

介绍了水溶性维纶的性能、应用和纺纱工艺。7.4 tex水溶性维纶纯纺纱的生产必须从合理的工艺配置、半制品的质量控制技术措施等方面着手,还需重视温湿度的控制,如此才能确保成纱质量水平。详细分析了各工序工艺配置对半成品和成纱质量的影响。     

驼绒/水溶性维纶包芯纱及其针织物退维工艺探讨

采用驼绒与水溶性维纶制备了几种包芯纱及针织物试样。通过正交试验对驼绒/水溶性维纶包芯纱及其针织物退维过程进行研究,探讨芯纱含量、包芯纱捻度、织物密度、温度、时间对退维率的影响。试验得出:包芯纱退维比针织物退维更容易,但维纶的溶解导致纱线收缩纠缠,且所形成的中空结构在编织过程中会受到破坏,因此选用针织物退维,试验结果表明:采用芯纱含量为19.1%,捻度为325捻/m的驼绒/水溶性维纶包芯纱,针织物总密度为1 368线圈/25 cm2时,在温度60℃下恒温处理40 min,针织物退维率可达99%。     

平行纺水溶性维纶包芯柔体纱生产工艺探讨

探讨平行纺水溶性维纶柔体纱的生产工艺利用空心锭子平行纺纱原理,纺制出涤纶长丝作为芯纱,水溶性维纶作为外包纤维,棉纤维平行排列的三组分包芯复合纱经过退维工艺,制成包芯柔体纱,并对退维前后纱线性能及退维工艺进行了测试分析认为:该纺纱方法退维容易,工艺简单,较好地提升了产品档次和附加值建议在满足织造要求的前提下,选择单包纺纱,退维容易且比较彻底还应合理控制退维温度、时间和浴比,并采用连续溢流换水方法,防止维纶分子进入棉纤维使纱线手感变硬,影响柔体纱品质。     

利用水溶性纤维开发低线密度纱线织物的研究

探讨利用水溶性维纶混纺开发纯棉普梳低线密度纱线织物的方法。采用水溶性维纶散纤维与棉卷混和一起喂入梳棉机以及三道并条混和的方法生产混纺纱,设计了两种组织的股线织物,测试了退维前后织物的表面结构、厚度、吸湿快干等性能。结果表明:开发生产的水溶性纤维普梳低线密度纱线织物经退维处理后结构完整,白度、光泽等外观有明显改善,厚度减小,干燥时间明显缩短,吸水性能显著提高。认为:该种混和方法混和均匀,退维后织物性能的变化与维纶含量、织物规格等参数有关。     

Application of RFID technologies in the temperature mapping of the pineapple supply chain

Current temperature tracking systems lack the convenience and accuracy demanded by the real conditions of a fast-paced produce supply chain. In recent years RFID technology has been suggested to be an enhanced method for temperature tracking because of its many benefits, such as using little instrumentation, offering the quick readings necessary for real-time decision making, and allowing the capture of long-duration temperature profiles. However its limitation lies in that probeless systems fail to provide accurate temperature readings in some of the critical points of the pallet and the load. The objective of this work was to study the use of RFID in temperature monitoring by comparing the performance of RFID temperature tags versus conventional temperature tracking methods, as well as RFID temperature tags with probe versus RFID temperature tags without probes and their utilization along the supply chain. Therefore, the temperature mapping of a shipping trial comprising pallets of crownless pineapples instrumented using different RFID temperature dataloggers and traditional temperature dataloggers and packed in two kinds of packages (corrugated boxes and reusable plastic containers) inside a container was performed. The results showed that RFID temperature tags are analogous with regards to accuracy to the conventional methods, but have a superior performance because they allow quick instrumentation and data recovery, and the possibility of accessing the sensor program and data at any point of the supply chain without line of sight. In addition, the use of RFID tags with probe was justified by its role in determining the efficiency of the pre-cooling operations and low temperature abuse tracking during transportation and refrigerated storage; while the RFID tags without probe proved useful for high temperature abuse monitoring during transportation and refrigerated storage. The creation of a RFID sensor with a probe, able to record both ambient and pulp temperatures simultaneously is suggested. Presented at Food Processing Automation Conference, American Society of Agricultural and Biological Engineering (ASABE), Providence, RI, USA, June 28–29 2008.     

Effects of Concentration,Bloom Degree,and pH on Gelatin Melting and Gelling Temperatures Using Small Amplitude Oscillatory Rheology

Concentration, gel strength (Bloom), and pH effects on both melting and gelling temperatures of gelatin were studied using small amplitude oscillatory rheology. Temperature sweeps were applied to gelatin gel samples for heating and cooling at fixed frequencies. Results showed that melting temperatures were higher than gelling temperatures, and both increased with increasing concentration at pH from 3 to 6 for all gel strength. For constant gelatin concentration and pH, as gel strength increased, melting temperatures decreased, whereas gelling temperatures increased. A mathematical model was obtained which correlates melting and gelling temperatures, respectively, with pH and concentration at fixed Bloom degrees. All gelatin gels showed storage modulus higher (2 to 10 kPa) than loss modulus (50 to 500 Pa).     

基于温度场的储粮区域划分研究

现阶段我国储粮生态区域划分为高寒干燥、低温干燥、低温高湿、中温干燥、中温高湿、中温低湿、高温高湿7个储粮区。按生态特点，15℃以上有效积温既有重叠交叉、又有隔离间断；年平均相对湿度范围跨度过大，在科学指导粮库建设、仓型选择上存在一定偏差。研究利用113座城市2018—2020年大气数据，通过统计分析，获得气温高于15℃不利积温与时长累积值这一最具特征指标，利用Origin软件构建积温云图，将储粮区划分为超低积温区、低积温区、中积温区、高积温区、大跨度积温区5个区域，建议将不利积温与时长累积作为储粮区划分主要指标。     

缓冲预处理对玻璃化转变温度的影响

利用调制式差示扫描量热仪对牛肉糜和牛肉肌动球蛋白在低温情况下的玻璃化转变温率进行了实验研究，发现肌动球蛋白在－10℃和－3℃附近有两次明显的吸热峰值，并且添加的羧甲基纤维素钠、海藻酸钠和明胶对DSC曲线无明显影响。从牛肉糜和牛肉肌动球蛋白的DSC曲线变化看，出现双吸热峰值与缓冲预处理过程无关。     

温度场下利用元胞自动机建立粮仓害虫模型研究

粮仓温度是影响粮仓害虫种群发展的主要因素之一,试验基于元胞自动机对赤拟谷盗害虫在静态温度场和动态温度场进行模拟,发现害虫种群为了适应生存会趋向于有利于本种群发展的温度。周围温度可以影响害虫种群的发展,区域位置的变化。结果表明通过改变温度,能影响害虫种群的发展趋势。如果害虫的变化跟不上温度的变化,将会因温度过高或者过低而死亡。     

冷季入温极差对汾酒发酵的影响

打破汾酒传统工艺入缸温度均一的发酵模式,将酒醅入缸温度进行差异化调整,考察入温极差对发酵过程及产酒情况的影响。结果表明:温度差异化入缸所产酒酒体"香气较大,乙酯香略突出,较醇厚,香味较长"。     

Effects of pH and temperature on metmyoglobin solubility in a model system

From a series of experiments heating metmyoglobin solutions at pH 5.0 through 7.0, the effects of temperature and pH on the thermal stability of metmyoglobin were investigated. The percent metmyoglobin denatured at temperatures from 25 to 80 °C was determined. pHs lower than 6.5 caused metmyoglobin denaturation at various temperatures from 25 to 80 °C, but it was particularly apparent when pH was < 5.6. Thermal stability of metmyoglobin increased as pH increased. Metmyoglobin denaturation occurred at 55 °C at pH 5, however, denaturation did not occur until 60 °C at pHs from 5.3 to 7.0. A slower heating rate (0.9 °C/min) resulted in more metmyoglobin thermal denaturation than a faster heating rate (1.3 °C/min) when the temperature was above 55 to 60 °C. The denaturation caused by low pH alone was reversible, while that caused by high temperature was not. Techniques which increase muscle pH, such as the injection of sodium bicarbonate, could effectively improve the color condition of PSE meat.     

Kinematic Viscosity of Ternary Aqueous Solutions of Ethanol and Sucrose

A capillary viscosimeter was used to measure the kinematic viscosity data of aqueous solutions of ethanol and sucrose at several temperatures (from 20 up to 45°C) and concentrations (from 5% up to 95.11% w/w ethanol concentration with variable sucrose concentrations as a function of its solubility). Two models were proposed for fitting the experimental data (one for water/ethanol and another for water/ethanol/sucrose solutions). These models were based in pre-existing equations like Redlich-Kister and Torok-Rard-Miller (for dependency on concentration), and also Vogel-Fulcher-Tamman (for dependency on temperature). The estimated values by these two models gave low deviations from the experimental data for binary and ternary mixtures.     

A constant humidity air supply system for pilot scale applications

This paper outlines the development of an apparatus to supply air with both controlled temperature and relative humidity, at a variety of flow rates up to 114 L min⁻¹. To achieve adjustable constant relative humidities in the air, the two-pressure principle was used. This method involved saturating the air at a higher pressure, and then passing the air through a pressure release valve to the lower working pressure to achieve the desired humidity, while controlling the temperature to the desired level. The absolute pressure when the saturation is achieved determines the humidity of the final air. Standard design procedures were followed to ensure the air approached saturation in the pressurized column and that the amount of water was sufficient to make sure the columns would not run out of water during an experiment. The problems encountered included a pressure fluctuation coming from the compressor through the pressure regulator, and a regular fluctuation in the temperature of the water, within a 90 min period, when the water temperature was used to control the air temperature exiting the column. These problems were overcome by using two-pressure regulators on the air supply and by controlling the temperature of the water rather than the air temperature. The result was a stable but adjustable temperature and relative humidity air supply.     

不同浸汁条件对山楂原汁品质的影响

以菲克浸透扩散定律为依据。就山楂的切片厚度、浸汁时间、浸汁温度3因素在不同的处理条件下对浸出汁的主要理化指标的影响情况做了分析比较。较理想的浸汁条件为:切片厚度2~3mm,浸汁时间10~12h,浸汁温度40℃。