压电陶瓷驱动高频喷射阀的结构设计

为了提高喷气织机的引纬性能,降低能耗,课题组设计了一种基于压电陶瓷驱动的高频喷射阀.首先对喷射阀的核心部件压电弯曲片的刚度性能做了仿真分析和理论验证;然后对压电陶瓷驱动型高频喷射阀进行FLUENT模拟仿真;最后利用MATLAB软件对压电驱动系统进行动态仿真,确认了合理的工作间隙,进而对喷射阀的结构进行了优化.模拟得到最...     

立式盘类转子动平衡机箱体有限元分析

为了解决盘类转子的动平衡问题,研究设计一种立式的自动平衡机,建立三维机构模型。通过有限元分析的方法,对其底面的箱体的框架和立柱进行载荷的力学性能分析,得到箱体的应力变化规律。结果验证了平衡机箱体在设计上的合理性及可行性,表明箱体整体满足设计的标准要求,可为同类型动平衡机整体及部件的设计优化提供了理论依据与参考,可有效降低产品开发的成本和缩短研发的周期。     

盘类转子可收缩式接盘自动动平衡机

为了解决盘类转子的动平衡问题,研究了立式盘类转子自动动平衡机的整体机构设计方案,对其进行功能模块化的划分,建立了其相互校正量闭环反馈系统以及校正系统工作流程图。在此基础上研究设计了一种新式的可收缩式接盘装置,消除定位夹紧时夹具产生径向力对主轴损害的功能;可收缩式接盘装置相对传统解决此类问题的技术结构简单易行,在提高了立式自动动平衡机可靠性的基础上降低了成本。     

纺织器材类高速回转体动平衡工艺的创新实践

为了解决纺织器材类高速回转体振动、磨损和噪声等问题,介绍回转体平衡的基本概念、类型及选择原则,阐述调整回转体质量分布的方法,给出回转体平衡精度的定义及其校正关系。以捻线锭子锭杆结合件为例,采用双面动平衡工艺校正法对其平衡工艺进行计算和设计,分析并确定动平衡工艺试验方案。指出:由多个回转体刚性组装的结合件需采用预动平衡法降低部分不平衡量;锭子锭杆结合件需先对锭杆进行预平衡工艺处理后,在去重面A、B预留一定的不平衡量以抵消出纱嘴的不平衡量;锭杆结合件动平衡工艺实践为组合式高速回转体动平衡工艺的创新提供一种新的思路和方法。     

一种立式动平衡机摆架结构的分析

在传统的立式动平衡机的基础上,设计一种新的立式动平衡机的摆架结构,并对这种摆架结构进行了振动分析,列出了其振动微分方程,对方程进行分析求解,并对这种摆架系统的特征和校正面的分离解算进行说明。     

造纸机械旋转件现场动平衡方法与实践

对造纸机械旋转件现场动平衡技术进行了系统研究.结果表明,对于现场诊断过程中可能出现的耦合故障,可通过模拟研究确定;影响系数法更适于造纸机旋转件的现场动平衡;采用非接触电涡流传感器测轴振较接触式传感器测振,减少了振动信号的干扰,实现了快速、准确对不平衡故障的诊断.通过对复卷机底辊的现场测试与动平衡实践,成功地完成了目标辊体的现场动平衡.     

纺机高速回转件的精密动平衡

本文介绍QJD-1A 型动平衡仪的平衡对象和效果,并分析设计特点与技术条件。在制造高速件的纺织机械厂,不仅对产品而且对加工产品的关键设备,可以建立起定期的振动分析和动平衡制度,在使用厂同样可以建立起例行的振动分析和动平衡制度.     

磨粉机磨辊动平衡的探讨

随着我国制粉设备迈上新台阶的同时,磨粉机磨辊动平衡的问题也摆上了议事日程,本文主要就磨辊动平衡精度等级的选择作一些探讨。众所周知,当机械不平衡时,会使运动副中附加摩擦力和在构件中产生附加应力,从而增加运动副中的磨损,影响构件的强度以至降低效率等.同     

纺织机械回转体动平衡研究

文章阐述了不同的动平衡方式和精度等级表示方法,对纺织机械回转体动平衡问题进行分类研究,并结合实例给出具体动平衡计算方法,为回转体动平衡问题提供解决方案。     

1760/350长网多缸文化纸机生产线的技术改造

分析了1760/350文化纸机运行达不到设计车速现象,找出了产生问题的主要原因--烘缸动平衡精度差,通过对烘缸动平衡校正,改造了烘缸旋转接头的型式,解决旋转接头虹吸管磨损问题,并完善了纸机流送系统、引纸系统,纸机车速由原来250m/min提高到320m/min,提高了约28%.     

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.     

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.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

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

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status