两种牦牛绒集聚纱性能的对比分析

探讨两种集聚纺装置纺制牦牛绒集聚纱和赛络集聚纱的成纱性能。分别采用网格圈式和空心罗拉式集聚纺装置纺制牦牛绒20.8tex集聚纱和16.7tex赛络集聚纱,并进行了性能对比测试。结果表明:纺制20.8tex牦牛绒集聚纱,两者毛羽水平相当,空心罗拉式集聚纺所纺纱强伸性能显著提高,条干均匀度略好;纺制16.7tex牦牛绒赛络集聚纱,空心罗拉式所纺纱强伸性显著提高,毛羽明显减少,条干均匀度显著改善。认为:实际生产中,可根据纺纱品种和质量要求,合理选择集聚纺装置和赛络纺工艺,能够纺制出性能较好,质量满足要求的牦牛绒纱。     

中空罗拉式集聚纺系统的改造实践

探讨中空罗拉式集聚纺改造装置的特点及使用效果.分析了现有网格圈式聚集纺存在的缺陷以及中空罗拉式集聚纺改造装置的结构特点和工作原理,并进行了纺纱效果对比试验.结果表明:中空式罗拉式集聚纺纱效果与网格圈式集聚纺纱效果基本相当.认为:中空罗拉式集聚纺装置对各类紧密纺纱号均有较强的适纺性;由于无网格圈及相关小部件损耗因而运行比较稳定,运转成本低,能耗较少,成纱质量较稳定.且对运行环境及清洁工作要求较低.     

空心罗拉式和网格圈式紧密纺成纱质量对比

简述了空心罗拉式紧密纺的成纱机理,并通过纺制C29.2 tex、CJ14.6 tex、CJ9.7 tex、CJ7.3 tex纱线,对空心罗拉式紧密纺和普通环锭纺、三罗拉网格圈式紧密纺、四罗拉网格圈式紧密纺在成纱质量方面进行了对比分析,通过分析指出:空心罗拉式紧密纺的成纱质量优于普通环锭纺纱,其成纱质量水平与网格圈式紧密纺基本相同。     

降低纱线毛羽的实践

为了降低纱线毛羽,提高筒纱质量,结合粘胶集聚纺11.7tex纱的生产实践,对影响纱线毛羽指数的几大因素,如器材专件、车间温湿度、络筒工序等进行了综合分析,并验证车间温湿度、钢丝圈钢领使用时间、络筒速度等对纱线毛羽指标的影响,提出相应的措施进行改进。指出:粘胶集聚纺11.7tex纱筒纱1mm毛羽偏高的主要因素是纺纱湿度和络筒湿度;要减少纱线毛羽,应合理设置工艺,配好器材专件,做好车间温湿度控制并加强管理及跟踪检测。     

空心罗拉式集聚纺包芯纱的工艺优化

探讨空心罗拉式集聚纺包芯纱的工艺优化。选用吸风压力、细纱捻系数、钢丝圈号数、氨纶丝预牵伸倍数等工艺参数,通过进行四因素三水平正交试验,优选出JC 14.8 tex(44.4 dtex)、JC 11.8 tex(44.4 dtex)两种棉氨纶包芯纱较优的纺纱工艺,并与同号网格圈式集聚纺棉氨纶包芯纱、传统环锭纺棉氨纶包芯纱进行了质量对比。认为:空心罗拉式集聚包芯纺采用优化后的工艺配置可纺制出质量较好的棉氨纶包芯纱。空心罗拉式集聚纺包芯纱和网格圈式集聚纺包芯纱的质量都明显优于传统环锭纺包芯纱。两种集聚纺包芯纱条干及强伸性能接近,3 mm毛羽数量基本相当,但空心罗拉式集聚纺包芯纱短毛羽数量相对较多,可在减少有害毛羽的同时,较好地满足某些织物保持手感柔软的要求。     

空心罗拉集聚压力对粘胶成纱性能的影响

探讨空心罗拉式集聚纺压力对粘胶成纱性能的影响。阐述了空心罗拉式集聚纺装置的结构和集聚原理。在加装该装置的DTM129型细纱机上,采用5种不同集聚压力分别纺制19.7 tex、14.8 tex、9.8 tex粘胶集聚纱。分析了集聚压力对粘胶集聚纱条干、毛羽、强力的影响。试验结果表明:随集聚压力的增加,粘胶集聚纱的条干CV呈改善趋势;纱号较细纱的改善作用比较明显,而纱号较粗纱的条干CV呈现波动的趋势,规律性不明显;集聚压力的增加有利于降低3 mm有害毛羽,纱号较细的9.8 tex纱、14.8 tex纱降低作用比较明显,对较粗的19.7 tex纱作用不明显;随着集聚压力的增大成纱强力呈增大趋势,但集聚压力达到一定数值后成纱强力则趋于稳定。认为:可参考以上试验结论,综合考虑纱线的性质和质量要求,选择适宜的集聚压力,达到满足使用要求、降低能耗、增加经济效益的目的。     

精梳纱络筒工序工艺探讨

分析络筒工序对CJ29.2 tex和CJ9.7 tex两种精梳纱毛羽的影响,从络纱速度和络纱张力两个因素,探讨了纱线毛羽在络纱速度和络纱张力相互影响、相互制约下的增长情况,并确定了两种纱线工艺参数调整的最优方案,使高速络筒时毛羽增长幅度达到最小.     

集聚纺纱方式对纱线性能的影响

为了探究集聚纺纱方式对纱线性能的影响,采用以传统环锭纺为基础的四罗拉网格圈紧密纺、紧密赛络纺、全聚纺及低扭矩纺四种集聚纺纱方式纺制了28.1、18.5、14.7 tex的纯棉纱。通过对纯棉纱线的断裂强度、断裂伸长率、毛羽和条干均匀度等性能进行测试分析,探究了四种集聚纺纱方式对纱线性能产生影响的原因。实验结果表明:由于不同集聚纺纱方式的成纱结构特点不同,影响了纱线的内在性能。紧密赛络纺的成纱强力最高,全聚纺的成纱有益毛羽最多,低扭矩纱在假捻器的作用下纱线品质得到了提高其纱线条干最好,紧密赛络纺的纱线总毛羽数最少。     

转轮集聚纺纱装置与工艺设计

针对目前负压式集聚纺能耗大的问题,设计了转轮集聚纺纱装置。选用粗纱定量为6.33 g/(10 m)的普梳棉粗纱为原料,采用转轮集聚纺纱装置与传统环锭纺,设计纺纱线密度分别为32.4、24.3、19.4 tex纺制纱线,并对其单纱线密度、断裂强度、毛羽、条干均匀度和捻度进行测试对比,客观评价该转轮集聚纺纱装置的应用效果。结果表明：与环锭纱相比,转轮集聚纱4 mm以上有害毛羽减少量达40%～80%,单纱断裂强度下降1%～3%,断裂强力不匀率下降25%～50%,24.3和19.4 tex的单纱条干均匀度有3%～6%的轻微恶化,捻度基本无影响,说明使用转轮集聚纺纱装置可显著减少纱线的有害毛羽;转轮集聚纺纱装置安装在前罗拉下方,可在环锭细纱机上快速安装与拆卸,实现传统环锭纺与集聚纺的便捷切换,同时该装置具有构造简单、能耗低等优点。     

集聚槽倾角对紧密纱质量的影响

探讨集聚槽倾角对紧密纱质量的影响。分析了紧密纺异形管集聚槽的形态与作用,并采用集聚槽倾角为5°、7°、9°3种不同的异形管,分别纺制5种不同线密度的紧密纱,进行纺纱质量对比试验。结果表明:随着集聚槽倾角的增大,单纱强力降低,有害毛羽数减少;集聚槽倾角的增大对29.2tex和19.4tex纱条干CV值影响规律不明显,但14.6tex、11.7tex与9.7tex纱线的条干CV值则随着集聚槽倾角的增大而升高。     

空心罗拉集聚纺吸风槽形对成纱质量的影响

探讨空心罗拉集聚纺吸风槽形对成纱质量的影响.选取8种不同截面形状尺寸的吸风槽形,分别纺制29.5 tex、14.8 tex、9.8 rex纯棉集聚纱,并对各项成纱性能指标进行测试分析.结果表明:当吸风槽宽度过宽、截面尺寸较大时,气流的横向集聚作用减弱,成纱质量较差;纱号不同,所适用的吸风槽形有所不同,随着所纺纱号变细,吸风槽的截面尺寸应相应减小;等宽且与须条方向平行的A形槽对提高成纱强力较为有利,而上宽下窄,具有一定倾斜角度的槽形对较细号纱的毛羽和条干较为有利.     

对AATCC 81湿处理纺织品水萃取pH值测试方法的探讨

在进行AATCC 81 pH值测试时,不同测试人员之间的结果偏差较大,可达0.2个pH单位。本文改进了测试方法,采用冷凝装置后,使数据的重现性较好。     

Numerical simulation of three-dimensional internal flow field in the spinning channel on rotor spinning unit北大核心CSCD

view of the complex airflow variation in spinning channel on air-extraction rotor, an unstructured fluid calculation domain with single phase and steady slate was built by ICKM CFI) and FLUENT software, based on RNG k-e turbulence physical model.The pressure-velocity coupling of I he internal How field in the spinning channel was solved through SIMPLE algorithm, and the mass flow difference between inlet and outlet Am =0.001 4 g/s was obtained through calculation.The numerical simulation satisfied the convergence condition of residual.The results showed that there was an obvious pressure gradient in the rotor, and the static and dynamic pressure gradually increased from central area of the rotor to the edge of condensing groove.Besides, there was turbulence velocity at the outlet of fil>er pipeline, and the air velocity(342 - 428.68 m/s) on the slip surface and flow area in the condensing groove was relatively high.The trajectory and boundary of two airflow lines in the spinning channel was clear and the flow direction was regular, the line characteristics conformed to the analysis expectation of the pressure field and velocity field.Our work strongly supports research on the flow field characteristics and spinning mechanism of high-speed rotor. © 2021 China Silk Association. All rights reserved.     

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.     

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.     

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.