气动折入边装置中纱线初始位置对折边效果的影响

为改进气动折入边装置的结构设计,提高纱线的折入效率和稳定性,采用数值模拟和实验相结合的方法,探究纱线初始位置对纱线折入的影响机制。基于单向流固弱耦合算法提出了适用于模拟纱线从斜吹到折入行为的数值模型,探究一端固定另一端自由的单根纱线在不同初始位置先后受斜吹和折入气流作用的运动规律。搭建可视化实验平台,通过高速摄像机记录纱线的运动行为。通过数值模拟结果和实验数据进行比较,验证了单向流固弱耦合算法的准确性。结果表明:纱线折入所需的时间和伸长量与其初始位置有关,折入效果与其初始纵坐标有关;不同初始位置的纱线均能在7.425 ms内完成折入。     

气动折入装置异向射流场中纱线的运动规律

为提高纯气动毛边折入装置的折入效率以及稳定性,对纯气动毛边折入装置的折入机制进行研究,建立纯气动折入装置二维纱线气流场流固耦合模型,对不同长度的纱线线头整个折入过程进行流固耦合仿真。对比实验中不同长度的纱线线头最终的折入状态,分析纱线与斜吹、折入气流场之间的相互作用以及纱线在该气流场中的运动规律。在仿真模拟中,斜吹气流作用在纱线线头上时,驱使线头向－y 方向移动;当纱线线头弯曲到一定程度时,开启折入气流,关闭斜吹气流,使纱线头端开始向－x 方向移动,并完成折入过程;随着长度的减小,纱线线头折入难度逐步加大。结果表明：在空间异向射流气流场的作用下,长度为10 mm的纱线可在5.7 ms内完成折入过程,可用于转速为800 r/min 的无梭织机的光边处理。     

新型织机折入边设计刍议

新型织机织物的边纹,由于引纬方式的改变,纬丝梭梭被剪断,而采用折入边、绞边、剪边和熔边等形式。本文仅对新型织机制织真丝绸中折入边的设计谈点看法,供参考。     

折入边装置应用于特种织物的实践分析

特种织物使用折入边装置的情况正在扩展,结合已知特种织物如黄麻、玻璃纤维、塑胶线等应用折入边装置的实践,对折入边装置自身的性能、可靠性和织物的边组织、钢筘、织物废边等上机工艺进行说明。总结实践经验,使折入边装置应用于其它特种织物时能更快地上织机调整,并在实际开机织造时提高效率。     

毕佳诺OMNI—280型喷气织机折入织边浅析

对毕佳诺ＯＭＮＩ－２８０型喷气机折入织边装置和折入边组织进行了简要分析，为引进喷气织机厂家用好设备提供参考。     

毕佳诺OMNI-280型喷气织机折入织边浅析

对毕佳诺OMNI－280型喷气织机折入织边装置和折入边组织进行了简要分析．为引进喷气织机厂家用好设备提供参考，     

斜吹气流入射角对纱线折入的影响

为优化无梭织造中纬纱气动折入装置喷嘴的设计,针对纱线线头进行气动折入时运动稳定性不高的问题,通过有限元分析软件建立二维流固耦合模型来研究纱线在不同角度气流作用下的运动规律。采用高速摄像机拍摄气动折入装置中纱线在不同工况下的运动状况,并与二维流固耦合仿真结果相验证。在仿真过程中,纱线固定端位于坐标原点,其初始位置处于X轴正方向。纱线自由端在斜吹气流作用下绕原点向Y轴负方向运动;当纱线运动至接近与Y轴平行时,斜吹气流关闭,折入气流打开并作用在纱线上使其继续运动至完成折入。研究结果表明:斜吹气流角度为90°、60°、45°、30°时,纱线均能在3.98 ms内完成折入动作;不同入射角度的斜吹气流对纱线折入稳定性有显著的影响;入射角度为45°的斜吹气流最为优异,大大提高了纱线折入稳定性。     

片梭织机折入边的结构与设计

介绍了片梭织机折入边的形成方法，根据折入边的组织结构，重点针对折入边双倍纬密带来的布边增厚、边经屈曲波增大而造成的织造难度，提出了锁边经的设置、布边降低厚度和减少交织点的方法，以及地一边交接处的经密控制等三大工艺要素的改进措施，并介绍了具有代表性织物的折入边工艺设计应用实例。     

围巾织物用折入边装置时边撑的设计和使用

围巾是种常见的装饰性织物，对布面质量和美观性要求很高。现在许多高档的围巾在织造时直接用折入边装置织成光边。折入边装置工作时对布边稳定性要求很高，就对边撑提出了高要求，要慎重选择使用。同时围巾上的流苏会卡在边撑内，所以要对边撑重新设计。     

片梭织牛仔布折入边的设计

片梭织机的布边成形方法很多,用以适应后整理及服装裁剪各加工工序的需要。瑞士苏尔寿昌蒂公司生产的片梭织机,所加工的织物约90,可以采用折入边。虽然牛仔布可以全部使用假纱罗边,但由于纱罗绞边边撑上的纱挡等小零件,运转中容易脱落,以及专用绞纱轴     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.