电容式均匀度仪基础问题的探讨

本分析了电容式均匀度仪传感器的工作原理，根据纱条在电容传感器中的实际情况及实验结果，提出了满意度很小时纤维物质和空气组成并联介质的分析方法，讨论了纤维的介电常数及混纺比对测试信号的影响，对于等定量或单位细度的混纺纱条，所产生的电压信号与混纺比成线性关系。     

Outlast改性腈纶棉混纺纱混纺比的优化

为了优化Outlast改性腈纶棉混纺纱的混纺比,设计了11种混纺比,通过对不同混纺比Outlast改性腈纶棉混纺纱的断裂强力、回潮率、熔融热焓值、结晶热焓值等指标进行测试分析与计算,并使用Origin7.5软件拟合出Outlast改性腈纶纤维含量与混纺纱各指标的模拟曲线和函数关系,采用多目标优化方法建立统一目标函数,利用lingo9.0软件确定出Outlast改性腈纶棉混纺纱的最优混纺比。表明:当Outlast改性腈纶纤维的含量约为60%时,纱线的综合性能指标达到最优。     

混纺比对竹浆棉混纺纱条干和毛羽的影响

为探讨竹浆纤维棉纤维混纺纱中竹浆纤维含量的变化对纱线条干和毛羽的影响规律,测试分析了不同混纺比例的竹浆纤维棉纤维混纺纱线的条干和毛羽性能.测试结果表明:当混纺纱中竹浆纤维与棉纤维混纺比为30/70时,混纺纱的条干明显恶化,在实际生产中,应避免选用这一临界混纺比;竹浆纤维与棉纤维混纺比在55/45～70/30之间时对纱线条干较有利;竹浆纤维与棉纤维混纺比例为55/45时,混纺纱的毛羽指数较低;综合考虑,竹浆纤维棉纤维混纺纱在混纺比为55/45时成纱性能较佳.     

竹炭改性涤纶纤维/棉混纺纱线力学性能研究

为了研究竹炭改性涤纶纤维/棉混纺纱中竹炭纤维含量与混纺纱力学性能的变化关系,对不同混纺比混纺纱线在YG061电子单纱强力仪上进行拉伸性能、应力松弛性能测试,并对测试结果进行了分析和比较.结果表明:竹炭改性涤纶纤维/棉混纺纱的断裂强力随着竹炭改性涤纶纤维含量的增加先有逐渐减小的趋势,然后增大.竹炭改性涤纶纤维/棉的混纺比小于临界混纺比时,混纺纱的断裂伸长率变化趋于平直;一旦超过临界混纺比,随着竹炭改性涤纶纤维含量的增加,断裂伸长率迅速增大.在实际应用中,混纺纱最低断裂强度对应的临界混纺比在设计中应尽量避免选用.随着竹炭改性涤纶纤维含量的增加,混纺纱的弹性越来越好.     

混纺比对丝维尔与莱赛尔混纺纱强伸性能的影响

探讨混纺比对丝维尔与莱赛尔混纺纱强伸性能的影响。运用混纺纱强度预测理论预测混纺纱强力,并对不同混纺比的混纺纱进行了拉伸性能试验,分析了混纺比与纱线强度之间的关系。结果表明:用理论模型预测的混纺纱强力变化曲线与实际测试曲线基本相符;混纺纱的断裂强度随着丝维尔纤维含量的增加而呈现逐渐降低的趋势,当丝维尔纤维的含量达到80%左右时,混纺纱线的断裂强度达到最低值。认为,实际生产中,可根据混纺比对强伸性能的影响规律,从调温要求和混纺纱的强度综合考虑,合理选用混纺比,混纺纱中丝维尔纤维的含量控制在50%左右比较适宜。     

用显微镜法分析涤棉混纺纱的混纺比

通过显微镜法与二组分法对涤棉混纺纱混纺比的对比测试,分析了涤棉混纺纱中两种纤维的混和均匀和纤维分布,成纱截面纤维根数与纤维细度,长度,体积质量之间的关系,并用回归分析法分析了显微镜法和二组分法测试的涤棉混纺纱的混纺比。结果表明：二组分法试验涤纶纤维净干重量混纺比与显微镜法试验涤纶纤维根数混纺比呈显著正相关,采用显微镜法测试涤棉混纺纱的混纺比弥补了二组分法不能测试少量试样的不足。     

竹炭改性涤纶纤维／棉混纺纱线力学性能研究

为了研究竹炭改性涤纶纤维／棉混纺纱中竹炭纤维含量与混纺纱力学性能的变化关系,对不同混纺比混纺纱线在YG061电子单纱强力仪上进行拉伸性能、应力松弛性能测试,并对测试结果进行了分析和比较。结果表明：竹炭改性涤纶纤维／棉混纺纱的断裂强力随着竹炭改性涤纶纤维含量的增加先有逐渐减小的趋势,然后增大。竹炭改性涤纶纤维／棉的混纺比小于临界混纺比时,混纺纱的断裂伸长率变化趋于平直;一旦超过临界混纺比,随着竹炭改性涤纶纤维含量的增加,断裂伸长率迅速增大。在实际应用中,混纺纱最低断裂强度对应的临界混纺比在设计中应尽量避免选用。随着竹炭改性涤纶纤维含量的增加,混纺纱的弹性越来越好。     

聚噁二唑纤维阻燃维纶纤维混纺纱的性能分析

研究不同混纺比的聚噁二唑纤维阻燃维纶纤维混纺纱的成纱性能。纺制了不同混纺比的聚噁二唑纤维阻燃维纶纤维混纺纱,并测试其拉伸性能、毛羽、条干均匀度和阻燃性能,分析了混纺比与纱线整体品质以及阻燃性能的关系。试验结果表明:当聚噁二唑纤维含量为30%时,混纺纱强度最低;随着聚噁二唑纤维含量的增加,混纺纱的条干均匀度和毛羽得到改善,阻燃性能下降,但燃烧过程中的尺寸稳定性变好。认为,应根据生产成本、纱线用途优选聚噁二唑纤维阻燃维纶纤维混纺纱的混纺比。     

牛角瓜纤维混纺纱的开发

探讨牛角瓜纤维混纺纱的开发要点。采用不同的混纺比,纺制了几种牛角瓜棉混纺纱和牛角瓜棉涤混纺纱,并对所纺混纺纱性能进行了测试分析。结果表明:随着牛角瓜纤维含量的增加,混纺纱强力和条干均变差;涤纶对条干均匀度改善较大;当牛角瓜纤维含量不超过40%时,纱线性能可以满足织造要求。认为:开发牛角瓜纤维混纺纱,除了要控制其混纺比外,还要选择性能及可纺性均较优的纤维品种与其混纺。     

磁性改性丙纶纤维混纺纱性能及混纺比的优化

探讨磁性改性丙纶纤维混纺纱性能及混纺比的优化.通过测试多种混纺比的磁性改性丙纶纤维混纺纱的断裂强力、断裂伸长、捻度、毛羽等指标,分析了纤维含量与纱线性能之间的关系,得出拟合关系式;进而根据多目标理论,利用MATLAB遗传算法工具箱对拟合关系式进行计算,选择纱线断裂强力、断裂伸长、毛羽数的权重系数,得出当权重系数为[0.5,0.2,0.3]时,磁性改性丙纶纤维竹浆纤维棉纤维混纺纱的适宜混纺比为67:20:13.     

电容检测纱线传感器转换特性对纱线不匀率测试的影响

讨论了纱线测试中受电容检测纱线传感器转换特性的非线性影响，测得的条干不匀率值与纱线的实际条干不匀率值之间的差异，从理论上估计了纱线在不同的电容检测槽内测试时，由于其截面充满系数不同而引起的相对差异，并用试验数据加以验证。     

Dielectric spectroscopy-based characterisation of different types of Paneer (Indian cottage cheese) in terms of texture,microstructure and functional groups

Different variants of Paneer were prepared with cow milk (CM), buffalo milk (BM), skimmed milk powder (SMP) and blends (40:60, 50:50, 60:40) of SMP with CM/BM. The Paneer composition, texture, microstructure and spread of functional groups were correlated with the dielectric capacitance values. Results depicted a strong correlation (R² > 0.95) between milk used for Paneer making and its proximate composition in terms of the capacitance value, and it was highest for CM followed by BM; 100% SMP Paneer recorded lowest values. Paneer made from blends of SMP and liquid milk had the lowest transmittance value, indicating higher total protein content.     

A capacitive technique to assess water content in extra virgin olive oils

The present research investigated the correlations between capacitance and water content of extra virgin olive oils (EVOO). A commercial capacitor probe for radio applications and an LCR meter were used for electric tests in the frequency range from 500 Hz to 512 kHz. Seventeen samples of different EVOO with a moisture content ranging from 178 to 1321 mg/kg oil were selected for study. To assess the influence of moisture only, the oil with the maximum water content was filtered down to 288 mg/kg oil and five samples with intermediate water contents were prepared and submitted to electrical measurements. Subsequently, the capacitance of all 17 EVOO samples was measured at selected frequencies.     

电子清纱器清除长粗节的效果分析

为有效清除布面上的粗经、粗纬疵点,充分发挥电子清纱器的作用,对五种型号的电子清纱器清除长粗节的效果进行了试验对比,结果表明:DQSS-14型、UQC型电容式清纱器和Payer-150型光电式清纱器清除长粗节疵点效率高且漏疵少.指出:DQSS-14型、UQC型电容式清纱器采用的是绝对测量方式,与采用相对测量方式的DQSS-1型、DQSS-4A型电容式清纱器对比,清纱门限范围扩大,切疵准确、漏疵少.     

纺纱过程均匀度检测及控制方法研究

针对现有纺纱生产过程中半制品和制品均匀度检测系统存在的检测精度低、反馈速度慢、调节工艺参数复杂等缺陷 ,提出了采用电容式传感器检测纺纱半制品均匀度的方法 ;并就此方法中存在的输入输出特性呈非线性曲线的缺陷 ,提出了采用计算机通过软件方式加以修正的设想 ,并给出了相应的计算机控制系统框图及程序流程图     

Influence of pulsed electric field energy on the damage degree in alfalfa tissue

The objectives of this study were to investigate the influence of pulsed electric field (PEF) parameters on the damage degree of alfalfa mash, and to determine the relationship between the maximum damage degree and the energy used. Alfalfa mash was treated with PEF at various electric field strengths of 1.25, 1.90, and 2.50 kV/cm. The capacitance of the discharge capacitor was varied from 0.5 to 1.5 μF in steps of 0.5 μF. The pulse number was increased gradually to the point where the impedance became constant. There was no significant increase in the rate of damage beyond 0.5 kJ applied energy. The rate of change of the damage degree at 0.5 kJ was highest when the capacitance was 1.5 μF for all the voltages. Increase in the electric field strength led to decrease in energy needed to obtain the maximum damage degree. To achieve an efficient result for alfalfa juice extraction, the capacitance of the discharge capacitor should preferably be 1 μF or more. In order to minimize energy consumption for a given damage degree in alfalfa, it is desirable to have the highest energy per pulse and fewer number of pulses.     

Design and performance of a capacitor sensor and impedance analyzer for nondestructive moisture content determination

In this work, the design and performance of a low-cost impedance analyzer, called the CI Meter, that was assembled and calibrated to measure impedance and phase angles at 1, 5 and 9 MHz is given. A cylindrical sample holder with a single set of parallel-plate electrodes embedded inside along its length that can hold samples (100–150 g) of peanut pods (in-shell peanuts) was built and used with this instrument. The measured values of impedance and phase angle with this experimental setup were used in an empirical equation to obtain the average moisture content values of peanut samples with moisture contents in the range of 6–23%. The moisture content values determined by this system and a commercial impedance meter were compared with those obtained by a standard method. For over 90% of the samples tested in the moisture range between 6 and 23% the moisture content values were found to be within 1% of the standard values for both systems. Ability to determine the average moisture content of in-shell peanuts without shelling and cleaning them, with a low-cost instrument, will be of considerable use in the peanut industry. This method could be extended to other types of in-shell nuts.

Electrical Properties of Garut Citrus Fruits at Low Alternating Current Signal and its Correlation with Physicochemical Properties During Maturation

In this research, local citrus fruits, namely Garut citrus, were analyzed for electrical properties related to physicochemical properties. Electrical measurement on fruit was done by using low alternating current with a frequency varying from 50 Hz to 1 MHz. The fruits are placed between two plate electrodes and treated as dielectric material. Electrical parameters per unit of weight were used in this study to compensate variations in weight. Electrical impedance, resistance, and reactance per weight of citrus fruits will decrease if the frequency is increased. Electrical circuit models have been constructed to describe the internal conditions of citrus fruits. To indicate the fruit maturity, the physicochemical properties were used, i.e., firmness, total soluble solids, pH, and hydrogen ion concentration. The value of resistance, impedance, and reactance per weight declined during citrus fruits maturation. The correlations between electrical and physicochemical properties are investigated too. The highest consistency of correlations happens at a frequency of 1 MHz. Based on the model of an electrical circuit, the highest value of electrical resistance is outer shell and the lowest is seed. And then, the highest value of electrical capacitance is albedo and the lowest is segment. Resistance values of the parts of citrus fruits, i.e., seed, segment, segment wall, and outer shell, were decreased during maturation. While capacitance value of segment, albedo, and flavedo were increased.     

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.     

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.