Optimization and performance evaluation of silk fabrics dried in the domestic dryer

To determine the optimal drying procedure for large load and non-ironing procedure for small load when silk fabrics were drying-cared in daily usage; change in appearance, mechanical properties and microstructure of silk fabrics before and after drying with various drying parameters (heater power, air velocity and drum-rotating speed) were investigated. Results revealed that the performance of silk fabric after drying is more sensitive to air velocity (humidity of drying-air) rather than heater power (temperature). Heater power of 3000W, air velocity of 8.5m/s and drum rotating speed of 45-50rpm (No.2) was proved to be optimal for drying silk fabrics due to its ideal smoothness appearance, dimensional stability and drying efficiency. When consumers dry a small amount of clothes, a drying procedure of heater power of 3000W, air velocity of 8.5m/s and drum-rotating speed of 0rpm (No.6) is more reasonable procedure because it reduces or eliminates ironing. And indicating drying in dryer can be an effective alternative to indoor-drying or sunlight-drying if suitable procedure being set. This finding provided reference for manufacturers to design and improve of dryers, especially for drying procedures optimization of delicate textiles, and consumers a feasible care method without reducing the quality of fabric.     

Modelling of the carding process for spunlace nonwovens with particular regard to selected mechanical parameters in a double-drum card. Part 2: Modelling of delay times in the longitudinal mixing process

Abstract

The production of Spunlace nonwoven fabric is a complex process and includes, among other things, several important stages, such as carding, needling and drying. One of the most important stages is the carding process, which has a significant impact on the shaping of the physico-mechanical and qualitative characteristics of the nonwoven fabric. The article presents the modelling of the carding process in a two-drum system. A mathematical model, determining the expected number of drum and carding card cycles was proposed. Based on this model, delays were determined, due to longitudinal shifts of fibre in the carding process. Numerical simulations have been made and discussed in relation to fibre collection factors, at different production speeds and the number of carding rollers in the worker-stripper system.     

Effect of Feed Concentration on the Production of Pregelatinized Starch in a Double Drum Dryer

An industrial-scale double drum dryer is operated for producing pregelatinized maize starches using feed starch slurries of different solids content. Steam pressure, the level of pool between the drums and speed of drums rotation are varied together with the feed solids content in a practical range of values. The response of the dryer is registered by measuring several output variables, i.e. external drum temperature, product moisture content, mass flow rate and specific load (equivalent to product's film thickness). Experiments are also conducted with a different steam pressure in each drum and by preheating the feed slurry. The measurements of this work demonstrate for the first time that the concentration-dependent rheological and transport properties of the drying material dominate the drying process over and above the thermal condition of the drums. This information combined with the notion of thick momentum boundary layers surrounding the drums at the region of the gap are employed to explain the material application as a thin film over the drums.     

棉织物干燥过程热湿传递特性软件计算与分析

以单层多孔薄棉织物为对象,分析并建立其热风干燥过程中的热质传递机理及数学模型,得到织物在烘干过程中含水率与温度的变化规律,并采用MATLAB APP designer设计了棉织物传热传质数值计算软件,简易又直观地显示了各干燥段干燥时间与温湿度变化曲线。结果表明,薄棉织物在干燥过程中,内部温度与含水率的梯度基本可忽略不计,薄棉织物恒速段干燥时间占总时间的70%以上,但在结束恒速干燥段后内部仍有一定的吸附水含量。可为印染热定形机的风道结构设计和棉织物热定形工艺参数的设定提供理论参考价值。     

Effect of dehydration on phenolic compounds and antioxidant activity of blackcurrant (Ribes nigrum L.) pomace

This study examined the effect of dehydration on the phenolic compounds and antioxidant activity of blackcurrant (Ribes nigrum L.) pomaces (DBP) subjected to hot air oven drying (HOD), industrial rotary drying (IRD) and freeze drying (FD). Temperature and residence time were evaluated for HOD, whereas air-on and air-off temperature, ratio of drum rotor speed to air speed and particle size were evaluated for IRD. The highest total anthocyanins (ATC) and flavonols (FLV) were obtained in particle size of> 5.0 mm using IRD at 475°C/97°C (air-on/air-off) and higher ratio of drum rotor speed to air speed. Smaller size particles were found susceptible to degradation due to high temperature and retention time applied in IRD, resulting in loss of phenolic compounds in DBP, and thus, HOD was deemed more suitable. Overall, drying method selection and parameters of operation are key in preserving the concentrations of individual HCA and FLV in DBP.     

ZJ116B型卷接机组滤嘴供应系统的改进

为解决ZJ116B型卷接机组生产中因滤嘴切割轮负压过大而造成滤棒缺失等问题,对机组的滤嘴供应系统进行改进。通过在负压管道上安装阀门机构,对滤嘴供应系统的负压值进行调节;为保证并行轮上滤嘴横移到位且切割轮、错位轮、加速轮上滤嘴不掉落,对滤嘴运动和受力进行分析,结果显示阀门开度为5/6、切割轮负压风孔半径由1.75 mm缩小至1.25 mm时,可大幅减少因滤棒卡阻而导致的切割轮上滤嘴缺失数量。以淮阴卷烟厂生产的“南京（煊赫门）”细支烟为对象进行测试,结果表明:改进后ZJ116B机组切割轮上滤嘴缺失数量减少97.59%且未出现设备停机现象。该技术可为提高细支卷接设备运行效率提供支持。      

基于DEM离散元技术的玉米直线振动筛仿真分析

目的：分析物料颗粒在直线振动筛面上的运动情况,以便直线振动筛的机构优化。方法：基于离散单元法,采用EDEM软件对直线振动筛面上物料颗粒的运动情况进行仿真分析。以堆积角为响应,采用批处理的形式对仿真物料颗粒的离散元仿真参数进行校准;采用SolidWorks软件建立直线振动筛的三维模型,以物料在筛网面的下落高度、物料颗粒的形状尺寸为变量,以物料颗粒在筛网面上运动的平稳程度为指标,通过仿真,观察物料颗粒在晒网面的运动速度及位置分布情况。结果：单球形颗粒的速度分布相对较大,在达到振动筛分平稳阶段,单球形玉米颗粒的速度分布相对稳定,颗粒跳动现象明显减少。双球形玉米颗粒的速度分布相对较小,在达到筛分的稳定阶段,双球形玉米颗粒的位置跳动比较明显。双球形玉米颗粒在振动筛面的速度明显低于单球形玉米颗粒,不同下落高度的单球形玉米颗粒对振动筛分有一定的影响。结论：在对直线型振动筛分设计过程中,不同的高度,不同的颗粒形状对筛分的效率都有较大的影响,基于离散元法可以有效地分析物料振动筛分情况。     

聚丙烯腈/聚氨酯透明膜的制备及其性能

为改善静电纺聚丙烯腈/聚氨酯(PAN/PU)纳米纤维透明膜的力学性能,在静电纺丝过程中采用旋转滚筒作为接收装置,并经热处理的方法制备取向性PAN纳米纤维增强PU基(PANNFs/PU)透明多孔膜。借助扫描电子显微镜、红外光谱仪、多功能拉伸仪表征纤维膜的形态结构和力学性能,并讨论了不同纺丝转速对PANNFs/PU膜力学性能的影响。结果表明:随着接收滚筒转速的提高,PAN/PU多孔膜中纤维沿着滚筒旋转方向排列的趋势越来越明显;当滚筒转速为1 500 r/min时,PAN/PU多孔膜沿滚筒旋转方向断裂应力为103.3 MPa;当PANNFs-PU透明膜沿滚筒旋转方向的断裂应力达到306.8 MPa,垂直滚筒旋转方向的断裂应变达到163.1%,PANNFs/PU透明膜的力学性能相比于PAN/PU多孔膜显著提高。     

新型粉丝烘干室流场模拟与结构优化

目的:提高现有粉丝烘干室热空气利用效率。方法:以k—ε湍流模型作为模拟分析的理论模型,应用Fluent软件对烘干室进行模拟仿真运算,得到空气在烘干室中的运动特征和流速分布情况。结果:对烘干室结构进行优化后,加入引流管道,较原烘干室在垂直于粉丝烘干板方向的速度可提升120.83%,对引流管道的横截面形状及尺寸进一步优化,200 mm×200 mm横截面的引流管道出口位置的平均速度较第1次优化后可提升19.2%,风速不均匀系数下降8.89%。结论:优化后,烘干室的热空气利用效率提高,各出口处风速均匀性表现得到改善。     

滚筒干燥数学模拟的研究进展

滚筒干燥机因其操作简便、适应性广、热效率高、干燥时间短而被广泛应用于食品工业中.以经验为基础的滚筒干燥工艺不能满足生产需要.建立滚筒干燥过程的数学模型有助于优化工艺参数、提高产品质量、改进滚筒干燥机设计.本文对滚筒干燥原理及其传热传质机理进行了概述,重点介绍了滚筒干燥过程数学模拟的研究进展,并通过对文献的分析总结,对数...     

织物纹样特征提取与匹配方法比较

针对织物纹样自动识别过程中因尺度、旋转和褶皱等因素引起图像差异的问题,探索了复杂纹样特征的准确提取与匹配方法。以江崖海水纹样为例,采集尺度、旋转、模糊、光照、褶皱5种变化下的织物纹样图像,分别运用尺度不变特征变换(SIFT)、快速鲁棒性尺度不变特征(SURF)、二进制鲁棒不变可扩展关键点(BRISK)3种方法提取纹样局部特征,然后采用欧氏距离进行特征匹配计算,最后通过随机抽样一致算法剔除误匹配对。结果表明:采用BRISK算法的准确配对率最高,平均准确匹配率达87.10%;褶皱对织物特征匹配的影响最大,该变化下BRISK算法的鲁棒性优于SIFT和SURF算法;BRISK算法速度最快,图像平均匹配时间0.551 s;在织物纹样特征匹配中,BRISK算法比SIFT和SURF算法具有更好的适用性。     

Microwave drying characteristics of potato and the effect of different microwave powers on the dried quality of potato

Little detailed information is available on the microwave drying characteristics of potato and the use of different microwave powers to dry food products. Experiments were conducted to study the microwave drying characteristics and the dried quality of potato. The study focuses on describing the microwave drying characteristics of potato and discussing the effect of sample thickness, drying power and mass. The results show that if the power level increases, the mass load decreases and the thickness of the sample decreases, the dehydration rate increases and the drying energy consumption decreases. There are two falling rate periods during microwave drying of potato: the first falling rate period is for a moisture content of more then 1.1 (dry basis, DB); the second falling rate period is for a moisture content of less than 1.1 (DB). The same water loss will consume more energy when the moisture content is less than 1.1 (DB). A two-stage drying process was employed during microwave drying of potato. The microwave power of the first drying stage differed form that of the second drying stage. The moisture content of the breakpoint for the conversion of the first drying stage into the second drying stage is a moisture content of 1.1 (DB). A quadratic orthogonal regression experiment was conducted, and the effects of slice thickness, the first drying load power and the second drying load power on sensory quality, the rehydration ratio and the energy consumption rate were established. The slice thickness, the first drying load power and the second drying load power linearly affected the three indices. The effect of the product of the second drying load power and the potato slice thickness on the rehydration ratio and the energy consumption rate is significant. The optimum drying parameter combination for the three indices was obtained. The rehydration ratio of the dried products decreased with an increase of the second drying load power and the slice thickness. The concave curves of the sensory quality versus the three factors were shown.     

聚乳酸棉混纺机织面料的生产

为了成功开发聚乳酸纤维织物,分析了聚乳酸纤维的性能,根据纤维性能特征,设计了聚乳酸棉混纺机织面料.在络筒工序采用中速、中张力;在整经工序采用适当的车速和张力;在浆纱工序浆料配方以被覆为主,兼顾毛羽,浆纱工艺以小张力、中车速为宜;在织造工序采用中低后梁、迟开口、早投梭、中张力的工艺原则,从而使织造效率保持在92%以上.     

对薄页纸机表面施胶装置的改造

在生产特种薄页纸时,通常需要对薄页纸进行表面施胶处理。但该过程通常会增大烘缸负荷,限制造纸机车速,降低生产效率。根据表面施胶的性能要求,通过对传统表面施胶装置进行改造,减小了表面施胶对烘缸干燥能力的影响。     

雪莲果热泵干燥特性及品质研究

研究雪莲果样品厚度、装料量、干燥温度、风速和旁通比对雪莲果热泵干燥特性及质量变化的影响。结果表明：雪莲果干燥速率随着样品厚度和装料量的增加而降低,随着干燥温度和风速的升高而增加。雪莲果热泵干燥过程绝大部分以降速干燥为主伴随相对较短时间的恒速干燥,而有些干燥速率曲线只存在降速干燥阶段。综合考虑单位能耗除湿率、色泽差异、收缩率、复水比,雪莲果热泵干燥最适参数范围：样品厚度2～4 mm、装料量1～2 kg/m2、干燥温度25～35 ℃、风速1.5～2.0 m/s。而旁通比对雪莲果热泵干燥进程影响不显著。     

汽车用机织座椅绒织物的开发

介绍了双剑杆织机机织绒的开发过程、生产工艺及成品的物理性质.机织座椅绒织物技术含量高,织造难度大.用一个产品的实例讲述了组织设计的要点和生产的各个工序应该控制的关键,通过均匀控制整经张力、采取较大的综平度等方法,减少了断经、开口不清等疵病,提高了生产效率,增加了产品开发的成功率.     

PROTOS2-2高速卷接机组调头轮技术的改进

PROTOS2-2高速卷接机组采用锥齿轮式锥形调头轮技术,安装精度要求高,在高速运行下容易产生磨损和噪声,在烟支交接点存在速度差异,对烟支交接造成较大冲击,容易影响烟支外观质量。为此,对PROTOS2-2卷接机组的调头轮进行了改进。改进后的锥形调头轮:①无凸轮结构,避免了高速旋转下凸轮磨损带来的不利影响;②利用独立伺服电机代替齿轮传动,避免了齿轮结构造成的易磨损、噪声大、安装要求高等问题;③烟支运动控制准确,保证了烟支在调头前后交接柔和平稳。PRO/E动态仿真结果表明,烟支交接速度和伺服电机扭矩均达到了预期设计效果。采用伺服电机驱动的锥形调头轮安装快速,调整方便,可以满足PROTOS2-2卷接机组16000支/m in的生产要求。     

High-oil-load encapsulation of medium-chain triglycerides and D-limonene mixture in modified starch by spray drying

Oil mixtures of medium-chain triglycerides (MCT) and D-limonene in mixing ratios from 10 to 100 wt% were encapsulated in modified starch (wall material) by spray drying to produce oil-rich powders. The oil load (mass ratio of oil mixture to wall material) of the infeed emulsion markedly influenced the properties of the infeed liquid and the characteristics of the resulting powder. The viscosity of the infeed liquid and the particle size of the powder exponentially decreased with increasing oil load, while the emulsion droplet size in the infeed liquid increased. In addition, retention of D-limonene during spray drying also decreased markedly with increasing oil load. Irrespective of the different oil loads and concentrations of the wall material, D-limonene retention was well correlated with the emulsion droplet diameter of the infeed liquid. The encapsulation efficiency of the oil mixture exhibited a maximum value (almost 100%) at an oil load between 0.5 and 1.0, before decreasing at higher oil loads. At an oil load of 2.0, the encapsulation efficiency of D-limonene was reduced to almost zero, while around 40% of the initial MCT was encapsulated in the powder. The increase in oil load also led to increased amounts of surface oil of MCT and D-limonene in the resulting powder due to the increasing emulsion droplet diameter of the infeed liquids. PRACTICAL APPLICATION: This study proposes the microencapsulation of medium-chain triglycerides under high-oil-load conditions by spray drying. The powders prepared by this process provide significant benefits in terms of rapid energy conversion after consumption without accumulation in the body. Important quality factors of the powder products such as the encapsulation efficiency and the amount of surface oil were examined to understand the optimum process conditions for spray drying.     

带地网贾卡经编针织物花纹图案的自动识别

带网孔效应的贾卡经编针织物花纹图案曲线复杂,导致织物意匠图的设计耗时费力,为简化这一设计过程,提出一种针对该类贾卡经编针织物花纹图案的自动识别方法。在扫描获取织物图像并预处理后,综合运用Laws纹理能量测量、迭代阈值分割、边缘光滑算法,自动获得织物花纹图案,进而生成意匠图。测试结果表明,这种方法能够有效地去除织物中网孔为图像识别带来的噪音,快速、准确地完成对所需花纹图案的自动识别,生成设计意匠图。识别准确率可达到90%,对于提高该类织物的设计效率具有实用价值。