Influence of yarn structures; part B-on performance and functional properties of carpets

Three different Indian wools of significantly different characteristics are selected for the study. Structurally different yarns were produced using different approaches of fibre mixing and spinning systems. The performance and functional properties of handloom carpets made from structurally different yarns were studied. Carpets made of multi-component engineered yarns give higher value of carpet durability factor, tuft withdrawal force, thermal insulation and lower burnt area in comparison to carpets made from control yarns.     

Study on thickness loss of cut-pile carpet produced with heat process-modified polyester pile yarn. Part I: static loading

Carpet as a home textile is usually subjected to static loading. Therefore, compression behavior or thickness loss after a long-term loading is important from point of view of carpet appearance as well as its lifetime. In this study, four types of cut-pile carpet were woven based on face-to-face weaving system. Pile yarns were air-jet textured polyester filament yarns that were modified by different heat processes. Then, the carpets’ compression behavior was investigated by static loading test. Results show that by increasing the temperature in setting of pile yarns twist at the autoclave process, the carpet static recovery increases. However, the friezing and heat-setting processes of pile yarns have no significant effect on the carpet static recovery.     

Study on thickness loss of cut-pile carpet produced with heat process modified polyester pile yarn. Part II: dynamic loading

Thickness loss (TL) is one of the most important mechanical properties in each carpet. In this research, four types of ATY polyester pile yarns were used to prepare the cut-pile carpet samples. They were normal ATY polyester filament pile yarns and three yarns that modified by heat processes including friezing, heat setting, and twist heat setting. Woven carpet samples are subjected to standard dynamic loading test. Results show that friezing and heat setting processes have no significant effects on carpet dynamic recovery or TL after dynamic loading. Also, decreasing temperature of twist heat setting, the polyester pile yarns could not modify carpet TL after dynamic loading.     

复合纱线结构对单纱强力利用率的影响与分析

纱线的强力利用率是关乎原材料性能是否得到充分利用的指标之一,为提高纱线强力在不改变原料的前提下,通过纺纱方式调整成纱的结构来提高其强力。为此,从理论公式预测角度和实验论证角度分别对单纱结构、股纱结构和包缠结构纱线的强力利用率进行了研究,用理论模型描绘出3种结构纱线在不同捻系数下的单纱强力利用系数,再通过实验在环锭细纱机上加捻长丝单纱和并捻长丝股纱,在花式捻线机上纺制包缠结构纱线,考虑了因加捻引起的纱线线密度和捻系数的增长因素,分析对比了3种结构纱线的单纱强度利用系数,结果与理论预测大致相似,因此,所推导的力学模型可以用来定量确定强度利用系数变化趋势,在纺纱之前可用来寻找较优的加捻工艺参数,对生产实践起到一定的指导作用。     

相依竞争失效模型下细纱机性能退化对成纱质量的影响

针对细纱机性能退化对纺纱质量影响难以精确表征的问题,首先,利用棉纺生产数据分析了细纱机性能退化对成纱质量指标的影响,研究了质量指标之间的关系。然后,通过细纱机性能退化的参数筛选、指标建立以及突发失效过程预测,对细纱机性能退化过程进行了表征。其次,利用Wiener过程、Weibull分布对细纱机性能退化过程进行了模拟,构建了一种基于Copula函数的细纱机性能退化相依竞争失效模型,并对比分析了模型应用前后纺纱质量关键指标的变化。最后,依托海量棉纺生产数据,验证结果表明构建的相依竞争失效模型较好地解决了细纱机性能退化对纺纱质量影响的问题,而且经模型应用,使得纱线的粗节减少了10.09%,毛羽减少了23.5%,单纱断裂强度提升了4.26%。     

棉/涤皮芯结构粗纱参数对其细纱结构与性能的影响

为探究皮芯粗纱参数对粗纱—细纱两步法纺制棉/涤皮芯结构短纤纱的外观形貌及性能的影响,研究皮芯粗纱纺纱工艺、粗纱定量、粗纱捻度,以及芯纤维含量等因素对棉/涤皮芯结构短纤纱的芯纤维外露比例和纱线性能的影响规律。并借助图像处理技术,实现了芯纤维外露比例的定量化测试。结果表明:当粗纱工序输出须条宽度由10.2 mm增至16.3 mm,皮芯粗纱中芯纤维束偏心度由26.5%降低至19.2%,细纱芯纤维外露比例降低11.3%(29.2 tex)和12.3%(19.4 tex);粗纱定量增大或捻系数减小,芯纤维外露比例降低;芯纤维涤纶含量由15%增加至25%,芯纤维外露比例增加35.6%(29.2 tex)和30.5%(19.4 tex)。     

Influence of fibre strength and yarn structural characteristics on tensile failure of blended spun yarns: a prediction model

The study reports on the static failure behaviour of P/V blended ring, rotor and air-jet spun yarns explained on the basis of fibre failure coefficient. Fibre failure coefficient is an index introduced to represent fibre break and slip in combination occurring during tensile failure. Fibre break/slip during tensile failure is found dependent on fibre strength, fibre cohesiveness and internal structural developments in yarns. Tensile failure behaviour of ring, rotor and air-jet yarns found to be different owing to their difference in fibre consolidation mechanism. The contribution of individual components towards fibre failure coefficient varies with the spinning technology. An attempt has been made to develop mathematical models to explain the spun yarn failure behaviour under static condition. The developed mathematical models have incorporated the fibre property (fibre strength) and few structural characteristics of yarns which are strategically selected to justify the essence of models to enhance the prediction capability. Individual models are developed for ring, rotor and air-jet yarns owing to their structural changes caused by their inherent fibre consolidation mechanism. The developed mathematical models are free from assumptions and based on pure applied mathematics and have very high potential for prediction of spun yarn failure behaviour.     

Simulation on fiber random arrangement in the yarn part II: joint effect of fiber length and fineness distribution

Simulation on fiber random arrangement in the yarn has been studied in our previous research, where only fiber length distribution was considered. In this study, fiber fineness distribution was also taken into account in order to study the joint effect of fiber length and fineness distribution on fiber arrangement in the yarn. Eight-millimeter term limit irregularity of simulated yarn can be re-expressed by calculating the irregularity of the total weight of fibers within each yarn subsection. It can be seen from the results that the calculated irregularities considering fiber fineness distribution are closer to tested values compared with those without considering fiber fineness distribution. Besides, when the variance of fiber fineness gets greater, the difference between the calculated values with and without considering fiber fineness distribution becomes more obvious. For fiber length, the effect of average fiber length on yarn limit irregularity is very little, while its distribution has no significant effect on yarn limit irregularity. The improved simulation on fiber random arrangement in the yarn is more reasonable and can be applied for the prediction of yarn qualities.     

A study on the kinetic behavior of Listeria monocytogenes in ice cream stored under static and dynamic chilling and freezing conditions

The kinetic behavior of Listeria monocytogenes in 2 commercial ice cream products (A and B) that were inoculated and stored under static chilling (4 to 16°C), static freezing (−5 to −33°C), dynamic chilling, and dynamic chilling-freezing conditions was studied, simulating conditions of the aging process and of normal or abuse conditions during distribution and storage. The ice cream products A and B had different compositions but similar pH (6.50 and 6.67, respectively) and water activity (0.957 and 0.965, respectively) values. For both chilling and freezing conditions, the kinetic behavior of the pathogen was similar in the 2 products, indicating that the pH and water activity, together with temperature, were the main factors controlling growth. Under chilling conditions, L. monocytogenes grew well at all temperatures tested. Under freezing conditions, no significant changes in the population of the pathogen were observed throughout a 90-d storage period for either of the inoculum levels tested (10³ and 10⁶ cfu/g). Growth data from chilled storage conditions were fitted to a mathematical model, and the calculated maximum specific growth rate was modeled as a function of temperature by using a square root model. The model was further validated under dynamic chilling and dynamic chilling-freezing conditions by using 4 different storage temperature scenarios. Under dynamic chilling conditions, the model accurately predicted the growth of the pathogen in both products, with 99.5% of the predictions lying within the ± 20% relative error zone. The results from the chilling-freezing storage experiments showed that the pathogen was able to initiate growth within a very short time after a temperature upshift from freezing to chilling temperatures. This indicates that the freezing conditions did not cause a severe stress in L. monocytogenes cells capable of leading to a significant “additional” lag phase during the subsequent growth of the pathogen at chilling conditions. As a result, the application of the model at chilling-freezing conditions resulted in satisfactory performance, with 98.3% of the predictions lying within the ± 20% relative error zone. The present study provides useful data for understanding the behavior of L. monocytogenes in ice cream stored under single or combined chilling and freezing conditions. In addition, the study showed that such data can be expressed in quantitative terms via the application of mathematical models, which can be used by the dairy industry as effective tools for predicting the behavior of the pathogen during the manufacture, distribution, and storage of ice cream products.     

A study of peeling-off tension in rotor spinning and its dependence on rotor and fibre variables part I: theoretical

While assessing the overall yarn tension in rotor spinning, most of the researchers have ignored the contribution of peeling-off tension (T₀) assuming this being small. However, experiments in the present study showed a significant discrepancy between the calculated and the measured mean yarn tension due to neglect of T₀. Further, T₀ has a bearing in twist propagation and compacting the fibres in the zone of Peripheral Twist Extent (PTE) for ensuring continuity of the yarn formation. In the present study, a theoretical deduction has been made to estimate T₀ by summing up the contributions due to fibre tension at the yarn formation point and the tension arising out of the length of the PTE sliding in the rotor groove. The dependence of T₀ on various rotor and fibre variables has also been established.     

A study on siro-, solo-, compact-, and conventional ring-spun yarns. Part II: yarn strength with relation to physical and structural properties of yarns

The strength of siro-, solo-, compact-, and conventional ring-spun yarns has been examined with reference to yarn migration parameters, spinning-in-coefficient, number of broken fibers, and yarn hairiness. The measured results are presented in the forms of diagrams and tables. Results reveal that at various levels of gage length and strain rate, siro-spun yarns exhibit the highest tenacity, followed by compact-spun yarns, solo-spun yarns, and conventional ring-spun yarns. Analysis of the results demonstrate that the higher tenacity values of siro-spun yarns can be attributed to the higher mean fiber position, higher migration factor, greater proportion of broken fibers, and lower hairiness. It is also found that the strength of yarns to a considerable extent is governed by yarn structure, gage length, and strain rate.     

New proposals on “hyperentanglement” of galactomannans: Solution viscosity of fenugreek gum under neutral and alkaline conditions

Previous studies have shown that double-logarithmic plots of ‘zero-shear’ specific viscosity versus degree of space occupancy (c[η]) for disordered polysaccharide coils fall into two linear regions, with an abrupt change in slope from ∼1.4 to ∼3.3 at c[η] ≈ 4, due to interpenetration of neighbouring coils to form an entangled network. For guar gum and other galactomannans of higher mannose:galactose ratio, however, the transition from dilute to semi-dilute solution properties occurs at lower degree of space occupancy (typically at c[η] ≈ 2.5) and the subsequent slope is steeper (typically ∼5). These departures from “normal” concentration-dependence have been attributed to association (“hyperentanglement”) of unsubstituted mannan regions of the galactomannan chains. The purpose of the present investigation was to test this interpretation by studies of fenugreek gum, in which the mannan backbone is almost fully substituted with galactose sidechains.     

Influence of processing conditions on the physicochemical and sensory properties of sesame milk: A novel nutritional beverage

Production of sesame milk is one of the methods for increasing consumption of sesame as an excellent nutritional resource. The aim of this study was to examine the effects of sodium bicarbonate concentration in soaking water (0, 0.5 and 1 g/100 mL NaHCO₃), roasting temperature (0 and 145 °C) and blanching time (0, 15 and 30 min) on physicochemical and sensory properties of sesame milk. Changes promoted by these processing conditions were also evaluated via color analysis and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The processing parameters mainly affected pH, total solids, protein, fat, ash, lipoxygenase activity, stability, specific gravity, viscosity, color features and sensory properties. Sensory evaluation revealed that overall acceptability was higher in all treatments than the control. SDS-PAGE analysis showed that 7S globulins decreased by roasting and soaking while 11S globulins of sesame milk proteins increased by roasting. The optimum processing conditions were found to be soaking in water containing 0.5 g/100 mL NaHCO₃, blanching for 15 min and without any roasting when desirability function method was applied.     

Influence of postharvest water stress on lipoxygenase and alcohol dehydrogenase activities, and on the composition of some volatile compounds of Gewürztraminer grapes dehydrated under controlled and uncontrolled thermohygrometric conditions

Gewürztraminer grapes with a sugar content of around 212 g/L (21.7^oBrix) were dried at 17^oC, 40% relative humidity and 1.5 m/sec air flow in a 300 L thermo-conditioned tunnel. Control grapes were dried traditionally in a window ventilated room, under uncontrolled environmental conditions varying with outside climate. Tunnel-dried grapes reached the desired sugar concentration (305 g/L, 29.5^oBrix) in 17 days, loosing 36% of their weight. Control grapes lost only 22% of their weight and grey mould developed in several bunches at the last sampling. Titratable acidity decreased for tunnel-dried and control grapes from 6.5 g/L to 4 g/L and 5 g/L, respectively. Lipoxygenase (LOX) activity declined in both samples from 120 to 90 U/mg protein dw, with a subsequent significant increase after 20% weight loss in tunnel-treated grapes while the control grapes showed a small peak (150 U/mg protein dw) at 13% weight loss. Six carbon compound evolution showed a loose correlation with LOX activity. Alcohol dehydrogenase specific activity and the concentrations of ethanol and of acetaldehyde plus ethyl acetate showed fluctuating patterns of change, with the evolution of these three variables showing similarity, particularly evident in the tunnel-dried grapes. Carotenoids declined significantly, to increase slightly at the end of the experiment in both samples, with the decline more rapid in the control grapes. Traditional, uncontrolled conditions, did not permit constant dehydration, and provoked a rapid stress to the berries (10% of weight loss). Controlled conditions permitted uniform dehydration, postponed water stress, giving a higher quality product without loss of berries.     

Modelling survival kinetics of Staphylococcus aureus and Escherichia coli O157:H7 on stainless steel surfaces soiled with different substrates under static conditions of temperature and relative humidity

The survival of Escherichia coli O157:H7 and Staphylococcus aureus on stainless steel surfaces with Saline Solution (SS), Tryptone Soy Broth (TSB) and meat purge was studied, and based on results, mathematical models describing survival of pathogens as a function of time were proposed. Results indicated that S. aureus was able to survive longer than E. coli O157:H7 in all substrates. The type of substrate had a greater impact on the survival of E. coli O157:H7. This microorganism only remained viable for 8 and 50 h (hours) on surfaces with SS and TSB, respectively while on meat purge, the microorganism could be recovered after 200 h. For S. aureus, SS and TSB led to similar survival times (250 h) whereas on meat purge, survival capacity increased to 800 h. Survival data for S. aureus could be well described by a log-linear model or a Weibull model depending on the type of substrate (R² > 0.85). E. coli O157:H7 displayed an evident tail zone which made the Weibull model more appropriate (R² > 0.94). These survival models may be used in quantitative risk assessment to produce more accurate risk estimates. Finally, the results highlight the importance of performing effective cleaning procedures to prevent cross contamination.     

Water sorption and cooking time of red kidney beans (Phaseolus vulgaris L.): part I – Effect of freezing and drying conditions on water sorption and cooking time

Water sorption and cooking time of kidney beans were determined. The beans were manually harvested at 19.2 ± 0.1% moisture content and stored at ?20 and ?10 °C for about half a year. The beans were further dried at 30, 40 and 50 °C inside a thin‐layer drier for 7.5 h or under room conditions for 4 week. The freezing storage temperature before the beans were dried did not influence their cooking time and water sorption. The saturated kernel volumes decreased approximately 7% after drying. The beans decreased their sphericity during water sorption and had a larger swelling ratio in the thickness direction than in other directions. Lower initial moisture content, especially with a higher drying temperature, decreased water sorptivity and resulted in higher percentage of uncooked kernels if the beans were not soaked before cooking. However, there was no relationship between initial moisture content and uncooked percentage if the beans were soaked before cooking. High drying temperature resulted in hard‐to‐cook (HTC) phenomenon.     

The effect of the research setting on the emotional and sensory profiling under blind,expected, and informed conditions: A study on premium and private label yogurt products

Although sensory and emotional evaluation of food products mostly occurs in a controlled laboratory environment, it is often criticized as it may not reflect a realistic situation for consumers. Moreover, products are mainly blind evaluated by participants, whereas external factors such as brand are often considered as key drivers of food choice. This study aims to examine the role of research setting (central location test versus home-use test) and brand information on the overall acceptance, and sensory and emotional profiling of 5 strawberry-flavored yogurts. Thereby, private label and premium brands are compared under 3 conditions: blind, expected, and informed (brand information). A total of 99 adult subjects participated in 3 sessions over 3 consecutive weeks. Results showed that overall liking for 2 yogurt samples was higher in the laboratory environment under the informed evaluation condition, whereas no effect of research setting was found under the blind and expected conditions. Although emotional profiles of the products differed depending on the research setting, this was less the case for the sensory profiles. Furthermore, brand information clearly affected the sensory perception of certain attributes but had less influence on overall liking and emotional profiling. These results indicate that both scientists and food companies should consider the effect of the chosen methodology on ecological validity when conducting sensory research with consumers because the laboratory context could lead to a more positive evaluation compared with a home-use test.     

A wild strain of Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) from farm-stored maize in South Carolina: Development under different temperature, moisture, and dietary conditions

The purpose of this study was to determine the duration of immature development and survivorship of Plodia interpunctella (Hübner) on maize over a range of temperatures and grain moisture contents encountered in maize stored on farms in the southeastern states (USA). Laboratory cultures were established with moths collected from farm-stored maize in South Carolina and maintained on cracked maize at 30 °C and 60% r.h. The incubation period and percentage hatch of eggs was determined at 18 combinations of temperature and r.h. Hatch was <1% at 15 and 40 °C. In the range 20-35 °C, percentage hatch declined as temperature increased, and the mean incubation period ranged from 3.1 to 8.5 d. Neither percentage hatch nor incubation period were affected by r.h. between 43% and 76%. The relationship between mean developmental period (oviposition to adult eclosion) and temperature was well described by a quadratic polynomial that predicted a decline from 67.6 to 30.1 d as temperature increased from 20 to 31.1 °C, followed by an increase to 38.5 d as temperature increased further to 35 °C. The results suggest a lower temperature threshold for development near 15 °C and an upper limit slightly greater than 35 °C. Moisture content had a significant effect on developmental period at all the temperatures studied, but the pattern of variation with moisture depended upon the temperature.     

Influence of Lipid Content in a Corn Oil Preparation on the Bioaccessibility of β‐Carotene: A Comparison of Low‐Fat and High‐Fat Samples

Some individuals with fat maldigestion have compromised digestive systems, which causes the incomplete hydrolyzation of ingested lipids within the gastrointestinal tract (GIT). We studied the influence of high‐fat (20%) and low‐fat (4%) contents on the bioaccessibility of a highly hydrophobic nutraceutical (β‐carotene) through a simulated GIT model consisting of mouth, stomach, and small intestine phases. The low‐fat and high‐fat values were chosen to simulate low‐fat and high‐fat diets. The triglycerides in the low‐fat system were fully digested, whereas those in the high‐fat system were only partially digested, thereby mimicking the digestive systems of individuals who exhibit fat maldigestion. The carotenoids were initially solubilized within oil‐in‐water nanoemulsions prepared using a nonionic surfactant (Tween 20) as emulsifier and a long‐chain triglyceride (corn oil) as the oil phase. After digestion, the total β‐carotene concentration in the filtered micelle phase was much greater for the high‐fat group (0.072 μg/mL) than for the low‐fat group (0.032 μg/mL). Conversely, the β‐carotene bioaccessibility of the high‐fat group (39%) was much lower than that of the low‐fat group (84%), which was attributed to a fraction of the carotenoids remaining in the nondigested lipid phase of the high‐fat group. These results highlight the importance of delivering hydrophobic nutraceuticals in a form where the fat phase is fully digested.