两种大提花面料主要性能的对比分析

为了研究莱赛尔大提花面料的基本性能,对比测试了莱赛尔大提花面料与棉与再生纤维素纤维交织大提花面料的拉伸断裂强力、顶破强力、耐磨性、刚柔性、悬垂性、保暖率、透湿性和折皱弹性等主要性能;试验结果表明：莱赛尔纤维大提花面料的经向拉伸断裂强力、抗顶破强力、柔软性、悬垂性、透湿性及折皱弹性均优于棉与再生纤维素纤维交织大提花面料,纬向拉伸断裂强力、耐磨性和保暖率低于棉与再生纤维素纤维交织大提花面料。     

储存时间对医用一次性防护服性能的影响研究

文章选取26件医用一次性防护服样品,针对其抗渗水性、断裂强力、断裂伸长率、阻燃性能、过滤效率、抗静电性6个项目进行测试,测试周期为每半年测试1次,共测试3个周期,将3次试验后的数据进行对比,分析储存时间对医用一次性防护服性能的影响。结果表明,储存期限对样品的抗渗水性及过滤效率未产生影响,对样品的断裂强力、断裂伸长率影响较小,但随着储存时间的增长,样品的抗静电性能、阻燃性能开始衰退,部分已无法达到标准要求。     

蚕丝/PHA长丝织物的性能研究

为了研究桑蚕丝与聚羟基脂肪酸酯(PHA)长丝交织物的性能,选用生丝作经线,PHA长丝或PHA长丝与桑蚕丝生丝交替作纬线,制成9种不同规格交织物坯布,进一步采用酶精练法脱胶制成成品,测试织物力学性能、抗皱性、起毛起球性、热学性能和通透性等服用性能。试验结果表明:蚕丝并捻后与PHA交织,织物的断裂强力、透气性、接触暖感和导热性均优于以单根蚕丝作经的织物,但抗皱性、透湿性和保温性下降。在织物纬向加入聚酯纤维,织物纬向断裂强力、断裂伸长、抗皱性、接触暖感和透气性增强,抗起毛起球性、导热性、保温性和透湿性下降。随着织物盖覆紧度的增加,织物拉伸性能、接触暖感和导热性均得到改善。总体而言,蚕丝/PHA织物经向拉伸断裂性能、抗皱性、保温性、通透性:斜纹平纹,导热性和接触冷感:平纹斜纹。     

含吸湿排汗涤纶面料的前处理

对含吸湿排汗涤纶纤维的混纺面料分别进行碱冷轧堆精练和热定形加工处理,测试其性能变化。结果表明,对织物进行碱冷轧堆精练时,较低碱浓度（100～150g/L）可以显著提高其吸湿透湿性;较高碱浓度对吸湿排汗纤维表面形态的损伤明显,吸湿透湿性下降,并使织物的断裂强力及断裂伸长率下降;选择适当的温度和拉伸率对吸湿排汗涤纶面料进行热定形,可以提高其吸湿性、断裂强力及断裂延伸性,但柔软度会变差。     

丝素整理棉织物技术

文章研究了丝素水解时间和碱溶液浓度整理棉织物后结构和性能的变化。断裂强力和断裂伸长随水解时间的延长而保持稳定,但达到120 min时显著降低;折皱回复性和白度随水解时间的延长而增加,但达到120 min时显著降低。断裂强力、断裂伸长、折皱回复性和白度随碱溶液浓度的增加而增加,但达到17%时显著降低。研究表明棉织物经过碱处理和丝素溶液整理破坏了纤维素的结晶结构,增加了丝素的可及性和交联性。在水解时间120 min、碱浓度17%时整理棉织物的效果最好。     

REF改性亚麻织物服用性能的研究

用REF对亚麻织物改性,和未改性的亚麻织物进行各项物理机械指标测试对比后发现:REF改性亚麻织物服用性能整体提高.主要体现在织物的弹性恢复性变好;回潮率、耐磨性能增加;柔软性和悬垂性提高:断裂伸长率增加而断裂强力下降:透气性和透湿性变差.     

浆纱可织性预测方法的探讨

1经纱织造断裂机理1.1纤维滑移和断裂引起的经纱断裂经纱织造断裂是由于纤维的滑移和断裂引起的。经纱上浆的目的主要是为了提高纤维的耐滑移性和保护纱线表面的纤维免受各种摩擦引起的纤维断裂。对于未上浆的纱,当其受到各种     

MTG酶处理真丝织物的性能研究

采用超声波结合MTG酶对真丝电力纺进行抗皱整理,通过MTG酶处理的时间、质量分数及温度单因素试验,全面考察了处理样的抗皱性、缩水性、白度、吸湿性及断裂强力和断裂伸长率等性能,选择出比较适宜的处理条件,并初步分析了原因。     

纤维素酶水解作用对织物性能的影响

采用酸性纤维素酶对纯棉、粘胶、竹浆织物进行酶水解处理,分析比较了水解处理前后织物的质量、断裂强力、折皱弹性、硬挺度、悬垂性等性能变化。结果表明棉、粘胶、竹浆织物经酸性纤维素酶水解处理后,竹浆织物的水解失重率最大,其次是粘胶织物;酶水解作用后,棉、粘胶、竹浆织物的坚牢性、外观形态保持性均降低,粘胶织物断裂强力损伤最严重,棉、竹浆织物的断裂伸长、折皱回复性降低严重,竹浆织物的硬挺度损伤最大,同时棉、粘胶、竹浆织物的悬垂性均得到改善,纯棉织物的提高最为显著。     

喷气涡流纺成纱工艺对色纺竹浆纤维针织物性能的影响

为研究喷气涡流色纺成纱工艺参数对色纺竹浆纤维针织物性能的影响,基于Box-Behnken设计方法,借助Minitab16软件,分析探讨了喷气涡流纺成纱工艺（喷嘴气压、纱线线密度、纺纱速度）对色纺竹浆纤维针织物断裂强力、透气性、悬垂性及耐磨性的影响。结果表明：纱线线密度减小,织物断裂强力下降,透气性和悬垂性先显著增加,而后略有下降;纺纱速度提高,织物断裂强力缓慢减小,透气性降低,悬垂性增加;喷嘴气压对针织物断裂强力、透气性、耐磨性均无显著影响,但当喷嘴气压增加时,织物悬垂性能先增加后降低;织物耐磨性主要受纺纱速度和纱线线密度的影响,且影响较为复杂。     

帘线钢丝铅浴淬火与水浴淬火组织性能对比

介绍帘线钢丝热处理的作用和淬火方式,说明铅浴淬火和水浴淬火的工艺原理和控制要点。指出经水浴淬火的钢丝组织以索氏体为主,有少量的铁素体,铅浴淬火后钢丝组织中的铁素体比水浴淬火的少些;铅浴淬火后钢丝的抗拉强度比水浴淬火后钢丝的抗拉强度略高,断面收缩率相差不大。使用证明:热处理1 t钢丝,采用水浴淬火工艺比铅浴淬火工艺减少铅耗0.9 kg,节约电能约100 kW.h,断丝率降低26.4%。     

Heating Characteristics of Ravioli in Brine and in Tomato Sauce Processed in Agitating Retorts

Ravioli in brine and in tomato sauce was processed in two agitating retorts to determine the heating lag within the ravioli and other critical parameters influencing sterilization. For 603 × 700 cans of ravioli in brine in a batch retort, ravioli fill was most significant. Increasing ravioli count from 100 to 130 decreased F, by 4.6. Spore count reduction and heat penetration conducted in the can and in a water bath indicated the F, in the ravioli was 4.6–8.5 less than in the brine. For 300 × 407 cans of ravioli in tomato sauce in a continuous retort, one significant factor was sauce consistency. The heating rate increased from an fb of 45.9 with full-strength sauce (2600 cps) to broken heating with an f2 of 14.9 when the sauce was diluted with water (280 cps).     

水分含量对鲜湿米粉品质影响

研究不同水分含量对鲜湿米粉成品感官品质,蒸煮特性方面影响;并研究水分含量对鲜湿米粉储藏期内感官品质、微生物指标、蒸煮特性(蒸煮损失率和熟断条率)和酸度影响。结果表明,水分含量为65%鲜湿米粉成品感官评分最高;在储藏期内,随水分含量增加,鲜湿米粉感官品质变劣速度、微生物指标超标、蒸煮损失率和熟断条率及酸度增加也越快。经综合考虑,选鲜湿米粉最宜水分含量为65%。     

低聚原花色素提取技术研究

分别以冷水、热水、乙酸乙酯 水、60％乙醇为提取剂,对葡萄籽中低聚原花色素进行提取研究。结果表明,以粉碎的葡萄籽、石油醚脱脂干燥后的葡萄籽壳为原料,乙酸乙酯 水为提取剂所得提取产物纯度高,提取率可达0.4％～o.6％,质量分数≥98％。     

紫外照射对留胚米稳定性的影响

为了提高留胚米的稳定性，采用紫外照射对留胚米进行稳定化处理。采用单因素实验及响应面分析研究紫外照射对留胚米脂肪酶灭活率的影响，同时考察留胚米水分损失率、碎米率和爆腰率的变化。结果表明：紫外照射最佳条件是照射时间11.50min，照射距离为4.5cm，初始水分含量13%，此时脂肪酶灭活率66.73%、且碎米率增加0.12%、爆腰率增加1.63%、水分散失率增加0.38%，处于可以接受范围内，因此可以选为紫外照射稳定留胚米的工艺参数。     

乳酸湿热处理改善大米粉性质及粉条品质的研究

主要研究乳酸湿热处理对大米粉性质及其干粉条和湿粉条品质的影响。以水磨籼米粉为原料,通过不同浓度乳酸、湿热以及乳酸与湿热联用的方法对米粉进行处理,研究不同条件下制备的大米粉的糊化特性、溶解度、膨胀率以及干粉条和湿粉条的蒸煮品质和质构品质。实验结果表明:乳酸湿热处理对大米粉糊化特性影响显著,大米粉通过湿热处理、乳酸处理、乳酸湿热联用处理后,大米粉的峰值黏度、谷值黏度、衰减值、最终黏度、回生值都有所降低。在乳酸处理(pH=4)时,峰值黏度最高。乳酸湿热处理对大米粉的溶解度和膨胀度都有一定的影响,与原样相比,被处理过的样品其溶解度、膨胀度都逐渐降低。在粉条蒸煮品质测定中,乳酸处理(pH=4)后,干粉条和湿粉条的断条率、蒸煮损失率都达到最低。在粉条质构品质测定中,经过湿热处理、乳酸处理和乳酸湿热联用处理三种方法处理以后,湿粉条的硬度、咀嚼性均有所下降,在乳酸处理(pH=4)时,湿粉条的弹性达到最大;在湿热处理、乳酸处理和乳酸湿热联用处理中,干粉条的黏度有所下降,在乳酸(pH=4)时,干粉条的弹性达到最大。最终结果:在乳酸处理(pH=4)时,对改善大米粉性质及粉条品质的效果是最优的。     

米蛋白-海藻酸钠互穿网络水凝胶的制备及性能表征

为满足食品领域目前对于高机械强度水凝胶的需求,本研究以碎米蛋白和海藻酸钠为主要原料,通过热处理和离子交联法制备一种高力学性能的食品级碎米蛋白（RP）-海藻酸钠(SA)互穿聚合物网络（IPN）水凝胶。通过改变米蛋白与海藻酸钠凝胶体系中米蛋白的浓度（80、100、120、140、160 mg/mL）调节IPN水凝胶的力学性能,混合液加热及钙离子交联形成水凝胶后,测定其质构性能、流变性能、白度、溶胀性、含水量等性质。结果表明:随着凝胶体系中碎米蛋白浓度的增大,RP-SA IPN水凝胶的储存模量G'、损耗模量G"和凝胶硬度均增加,当碎米蛋白浓度达到为140 mg/mL时,凝胶硬度增加幅度变小。水凝胶溶胀性先降低后趋于平缓,但水分分布更为均匀。因此,适量的碎米蛋白能对RP-SA IPN水凝胶网络有很好的填充效果,并对水凝胶的形态没有太大的改变,同时可通过调节蛋白的添加量来调节水凝胶的力学性能,该研究为米蛋白在食品领域的应用提供了理论基础。     

双捻机生产钢丝绳过程中断丝原因分析

捻股生产过程中细规格制绳钢丝断丝率出现较大波动。制绳钢丝生产时,选取的半成品钢丝进线直径为0.7 mm,加热温度900～1000℃,铅温550～600℃,Dv值30 mm.m/min,水箱拉丝生产出线直径0.15 mm,拉拔速度8～10 m/s,定尺长度32000 m,抗拉强度2650～2850 MPa,锌层面质量12.3～15.4 g/m2,扭转值波动较大。对双捻机捻股断丝断口进行扫描电镜分析,导致断丝率高的原因是电镀锌生产时钢丝出现氢脆。改进生产设备,采用滴定添加系统,进行电镀锌H2SO4溶液的添加,精确控制电镀溶液pH,确保生产稳定进行,降低了捻制断丝率,提高生产效率。     

Comparison of casein micelles in raw and reconstituted skim milk

During the manufacture of skim milk powder, many important alterations to the casein micelles occur. This study investigates the nature and cause of these alterations and their reversibility upon reconstitution of the powders in water. Samples of skim milk and powder were taken at different stages of commercial production of low-, medium-, and high-heat powders. The nature and composition of the casein micelles were analyzed using a variety of analytical techniques including photon correlation spectroscopy, transmission electron microscopy, turbidity, and protein electrophoresis. It was found that during heat treatment, whey proteins are denatured and become attached to the casein micelles, resulting in larger micelles and more turbid milk. The extent of whey protein attachment to the micelles is directly related to the severity of the heat treatment. It also appeared that whey proteins denatured during heat treatment may continue to attach to casein micelles during water removal (evaporation and spray-drying). The process of water removal causes casein and Ca in the serum to become increasingly associated with the micelles. This results in much larger, denser micelles, increasing the turbidity while decreasing the viscosity of the milk. During reconstitution, the native equilibrium between colloidal Ca and serum Ca is slowly reestablished. The reequilibration of the caseins and detachment of the whey proteins occur even more slowly. The rate of reequilibration does not appear to be influenced by shear or temperature in the range of 4 to 40°C.     

Thermophysical properties and thermal behavior of leafy vegetables packaged in clamshells

Little is known about the thermophysical properties of fresh-cut lettuce other than heat of respiration. Empirical correlations based on food composition remain the only way to estimate the thermophysical properties of fresh-cut lettuce. The objectives of this study were (i) to determine the thermophysical properties of several baby-leaf lettuce and brassica greens and (ii) to verify the measured thermophysical properties by using them in a heat transfer model and comparing the predicted product temperatures with measured product temperatures in a simulated interruption of a cold chain. Density, leaf thickness, thermal conductivity, specific heat and water activity from nine varieties of baby-leaf lettuce and brassica greens were measured. A broken cold chain was simulated in a low temperature incubator set at 10 °C for a length of time before readjustment at 2 °C. Results showed that density (1078–1112 kg m⁻³), leaf thickness (0.18–0.54 mm), thermal conductivity (0.55–0.70 W (m °C)⁻¹) and specific heat (3.1–4.3 kJ (kg °C)⁻¹) varied significantly (P < 0.05) between varieties. However, no significant differences were observed for water activity (0.959 ± 0.006). Using thermophysical properties as input in the heat transfer model, experimental and calculated temperatures were well correlated (R² = 0.98) with a root mean square error of 0.57 °C over the 10–40 mg CO₂ (kg h)⁻¹ range of respiration rate. The measured thermophysical properties adequately predicted the temperature of the baby-leaf greens during simulated broken cold chains. A sensitivity analysis performed with the heat transfer model showed that the thermal conductivity, the specific heat and the density were relatively more important on the thermal behaviour of the baby-leaf greens than the heat of respiration.