A novel approach to the Poisson’s ratio of the yarn

Abstract

The Poisson’s ratio is a fundamental and inherent property of the materials in their reaction to loading. Determining the correct value of the Poisson’s ratio leads to more accurate predictions of the mechanical behavior of the material, especially in employing mechanical or numerical finite element modeling methods. In this study, seven different types of medium and coarse yarn were digitally filmed in seven sections from three various angles while tensile strength testing. Then, longitudinal and transverse strains and consequently, momentary deformation index and Poisson’s ratio of the yarns were calculated. Significance level of the mean Poisson’ ratio was also determined at different angles and sections using statistical comparison test. The results showed that the transverse strain has a convergent state at the end of the test and the start of the yarn breaking occurs at the convergence point. Additionally, in upper sections of yarn near to the movable jaw of the strength tester, the amount of the longitudinal strain increases which leads to reduce in momentary deformation index and Poisson’s ratio of the yarn. Moreover, a sectional mode to measure the Poisson's ratio was presented.     

Analysis of warp-knitted fabric structure part IV: modeling the initial Poisson’s ratio in elastic deformation region

The effect of Poisson’s ratio on the mechanical properties of fabrics is undeniable. In the present study, a geometrical model for the Poisson’s ratio of two-guide-bar warp-knitted fabrics is developed, based on the presented models in the previous parts of this series. For this purpose, warp-knitted fabrics are categorized into two groups, according to their structures. Thereafter, a geometrical model is presented to predict the Poisson’s ratio of each group. To verify the generated models, theoretical results are compared with the available experimental data. The results show that the generated models are a suitable guidance to consider the Poisson’s ratio of warp-knitted fabrics.     

Poisson’s ratio of the MDF in respect to vertical density profile

The work deals with Poisson’s ratios (PR’s) of medium density fiberboard (MDF) measured using digital image correlation and correlated to vertical density profiles (VDP). MDFs of four different thicknesses were first scanned by X-ray to obtain VDPs and then subjected to compression while measuring by DIC. PR’s of MDF reveal low correlations with VDP (<0.08), but strong local behavior ranging from 0.025 to 0.06 for 12 mm thickness, from 0.018 to 0.105 for 18 mm, from 0.03 to 0.175 for 25 mm, and from 0 to 0.43 for 38 mm.     

Investigating the effect of weight reduction treatment on Poisson’s ratio of microfiber polyester woven fabric

Polyester is one of the important fibers among man-made fibers. One of the finishing processes for improving the performance of polyester fabrics is weight reduction treatment. This treatment has a considerable effect on the mechanical properties of such fabrics. In this research, the effect of weight reduction treatment on changes in the Poisson’s ratio of a microfiber polyester woven fabric treated with four different sodium hydroxide concentrations was studied. Poisson’s ratio of the fabric at 10 levels of extension was measured. Results show that from 1% to about 5%, the Poisson’s ratio increases non-linearly. After this point up to 10%, the Poisson ratio decreases by a linear trend. There is a significant variation in the results at lower extensions, and by increase in extension, this variation reduces. Statistical analysis showed that weight reduction at percentages lower than 25% does not affect the Poisson’s ratio of the fabric. In the range of 6–10%, there is a high non-linear correlation between the weft crimp and Poisson’s ratio. In addition, there is a high non-linear correlation between Poisson’s ratio and fabric cover factor.     

Young’s Modulus and Poisson’s Ratio Changes in Japanese Radish and Carrot Root Tissues during Boiling

Young’s modulus and Poisson’s ratio changes in Japanese radish and carrot during boiling were examined. Young’s modulus decreased rapidly within 2 min, then the decrease moderated. Carrot (3.0 to 0.5 MPa) exhibited increased modulus values relative to radish (1.8 to 0.3 MPa) during the same boiling period. Poisson’s ratio decreased slightly during boiling; carrot Poisson’s ratio (0.40 to 0.33) was smaller than radish (0.35 to 0.23) during the same boiling period. Boiling in saline solutions increased moduli reductions under the same treatment conditions. These results indicated that carrot maintained hardness, but reduced volume relative to radish during boiling.     

A method for the analysis of multiple novel halogenated flame retardants in cow’s milk

A method was developed for the extraction and analysis of cow’s milk to measure 21 halogenated flame retardants (FRs), including individual isomers plus eight methoxy-polybrominated diphenyl ethers (MeO-PBDEs). Extraction was performed using homogenisation with acetone:hexane with size exclusion chromatography followed by adsorption chromatography clean-up. Analysis was undertaken using gas chromatography high-resolution mass spectrometry. The method was validated in fortified cow’s milk with FRs and 2-methoxy-PBDE 68 at three levels (low [12.5–1250 pg g^–1], mid [37.5–5000 pg g^–1] and high [400–10 000 pg g^–1]). Additional methoxy-PBDEs were tested at two fortification levels. Isotope dilution was used to correct for losses during sample preparation and average recoveries ranged from 58% (allyl 2,4,6-tribromophenyl ether [ATE]) to 121% (γ-tetrabromoethylcyclohexane (γ-TBECH)). Limits of detection ranged from 0.055 pg g^–1 (6-methoxy-PBDE 47) to 38.9 pg g^–1 (decabromodiphenylethane (DBDPE)). Matrix effects were overcome through the use of surrogate and performance standards. A single FR (1-bromomethyl-2,3,4,5,6-pentabromobenzene [PBBB]) and two methoxy-PBDEs were detected in commercially available cow’s milk collected from local supermarkets in Ottawa, ON, Canada. Detection frequency was < 25% for these compounds and, where present, concentrations were low.     

Construction of recombinant industrial brewer’s yeast with lower diacetyl production and proteinase A activity

The characteristic buttery taste of diacetyl has long been a major problem in the brewing industry, and the foam stability of unpasteurized beer is often influenced by proteinase A (PrA), which is encoded by PEP4 and released from yeast cells into beer during brewing. A recombinant industrial brewer’s yeast strain that reduces the diacetyl content of beer and improves foam stability was constructed. We constructed a PGK1p-ILV5-PGK1t expression cassette, which was introduced into one of the PEP4 alleles via PCR-mediated homologous recombination. Then, the second PEP4 allele was disrupted using the Cre-loxP recombination system, and the recombinant strain was designated as S-CSIK12. The results show that the diacetyl production of S-CSIK12 is always lower than that of the host strain at all stages of beer fermentation. In addition, brewing with S-CSIK12 reduced the PrA activity of the final beer by 44 % compared with that using the wild-type strain. The head retention of the beer brewed with S-CSIK12 (260 ± 2 s) was better than that of the host strain S-6 (212 ± 3 s). Considering that more PrA is released from yeast cells during the final stage of main fermentation and that the timing of yeast cropping is determined by diacetyl reduction, brewing with strains that have low diacetyl production also reduced the PrA activity of the beer and improved its head retention. The present study provides reference for the brewing industry as well as research on the diacetyl reduction and foam stability of beer.     

Brewer’s yeast in controlled and uncontrolled fermentations,with a focus on novel,nonconventional, and superior strains

Historically, brewing beer came from uncontrolled spontaneous fermentations; nowadays, spontaneous fermentation is still used in speciality products such as Belgian acid beers (e.g., lambic, gueze, and Rodenbach) or in various traditional beers worldwide. On the other hand, industrial fermentations sometimes require a combination of phenotypic traits that might not be commonly encountered in nature. In some cases, the demand for increased productivity, as well as changing consumer preferences, leads to a great interest towards improvement and/or design new strains or yeast variants. This review addresses the following topics: controlled and uncontrolled fermentations, and advances in the selection of novel, nonconventional, and superior strains for beer.     

Experimental determination of elastic modulus of elasticity and Poisson’s coefficient of date palm tree fiber

The present study is an attempt to valorize local vegetable fibers by evaluating thire effectiveness as a new composite biomaterial. Our aim was to determine the mechanical characteristics, namely the elastic modulus and Poisson’s coefficient, of a fiber, locally called “Lif,” that is a natural material extracted from different date palm tree varieties in Biskra, a region situated in southeastern Algeria. This study compares the mechanical characteristcs of the Lif date palm tree fiber with other synthetic and plant fibers studied previously.     

A role of sea buckthorn on Alzheimer’s disease

Evidence suggests that diets rich in antioxidants reduce the risk factors of Alzheimer’s disease (AD). Hippophae rhamnoides, commonly known as sea buckthorn (SB), is rich in antioxidants which could have direct effects on amyloid-beta (Aβ) levels and consequently influence AD pathogenesis. In this study, sea buckthorn powder (SBP) was administered at varying concentrations (0.6, 0.9, 1.2, 1.5 and 1.8 µg mL⁻¹) to cell cultures (BE(2)-M17) with 20 mm Aβ for 72 h. MTS test indicated that SB significantly increased cell viability in Aβ-induced cells up to 95%. Results of Western blot showed maximum 38% inhibition of Aβ compared to the control (Aβ only). ELISA demonstrated significantly lower amyloid-β level (6672 pg mL⁻¹) than the control (10189 pg mL⁻¹). Images of AFM further confirmed the presence of low quantity of amyloid beta in SBP-treated cells. These findings suggest that SB warrants further investigation as potential therapeutic agent in the treatment of AD.     

A novel α-l-rhamnosidase with potential applications in citrus juice industry and in winemaking

The production of monoglycosylated flavonoids by α-l-rhamnosidases (EC 3.2.1.40) is an interesting development in biocatalysis. Applications of rhamnosidases in industry include removal of bitterness caused by naringin from citrus juices. In the present work, a psychrotolerant bacterial strain with α-l-rhamnosidase activity was isolated. The α-l-rhamnosidase was found to be able to degrade naringin and was purified and characterized. The α-l-rhamnosidase from Brevundimonas sp. Ci19 was able to release both rhamnose and prunin from naringin. The enzyme was partially purified with a performance of 2.7-fold purification. The α-l-rhamnosidase showed an optimum pH between 6.00 and 7.00 with substantial residual activity at pH 5.00 (85.3 %). The optimum temperature was between 20 and 37 °C. The enzyme showed activation in the presence of Ca²⁺ and Cd²⁺ ions and at a high ethanol concentration level (10 % v/v). Activity was found for β-d-glucosidase (EC 3.2.1.21) in the partially purified extract, but it was inactive in the acid pH region. This result indicates the potential for inactivation of β-d-glucosidase along with the high level of α-l-rhamnosidase activity necessary for the production of flavonoid glycosides. The α-l-rhamnosidase from Brevundimonas sp. Ci19 showed interesting properties for potential use not only in the citrus juice industry but also in winemaking.     

Scanner Digital Images Combined with Color Parameters: A Case Study to Detect Adulterations in Liquid Cow’s Milk

This study presents a proposition of a low-cost screening method for detection and quantification of adulterations in liquid cow’s milk samples. The studied adulterations were made with water and NaOH. Digital images from the adulterated samples were obtained using a flatbed scanner, and the means of ten color parameters were used to evaluate the information from images: red, green, blue, hue, saturation, value, relative colors (r, g, and b), and intensity. Regression models for water quantification were proposed using multiple linear regression (MLR), principal components regression (PCR), and partial least squares (PLS). The best models were obtained using PCR and PLS, with root mean square error for prediction smaller than 7%. These results were compared with near-infrared (NIR), and the prediction capability was very similar. In the case of adulterations with NaOH, the colors B, S, g, and b presented the highest differences between fresh and adulterated milk samples.     

A novel thermostable β-galactosidase from Bacillus coagulans with excellent hydrolysis ability for lactose in whey

β-Galactosidase is one of the most important enzymes used in dairy industry. Here, a novel thermostable β-galactosidase was cloned and overexpressed from Bacillus coagulans NL01 in Escherichia coli. The phylogenetic trees were constructed using neighbor-joining methods. Phylogeny and amino acid analysis indicated that this enzyme belonged to family 42 of glycoside hydrolases. The optimal pH and temperature were, respectively, 6.0 and 55 to 60°C. The purified enzyme had a 3.5-h half-life at 60°C. Enzyme activity was enhanced by Mn²⁺. Compared with other β-galactosidases from glycoside hydrolase family 42, B. coagulans β-galactosidase exhibited excellent hydrolysis activity. The Michaelis constant (K_m) and maximum rate of enzymatic reaction (V_max) values for p-nitrophenyl-β-d-galactopyranoside and o-nitrophenyl-β-d-galactopyranoside were 1.06 mM, 19,383.60 U/mg, and 2.73 mM, 5,978.00 U/mg, respectively. More importantly, the enzyme showed lactose hydrolysis ability superior to that of the commercial enzyme. The specific enzyme activity for lactose was 27.18 U/mg. A total of 104.02 g/L lactose in whey was completely hydrolyzed in 3 h with addition of 2.38 mg of pure enzyme per gram of lactose. In view of the high price of commercial β-galactosidase, B. coagulans β-galactosidase could be a promising prototype for development of commercial enzymes aimed at lactose treatment in the dairy industry.     

Thirty years of ‘quiet eye’ with etafilcon A contact lenses

Frequent replacement contact lenses made from the etafilcon A hydrogel lens material were introduced onto the market over 30 years ago, and etafilcon A remains the most widely used hydrogel lens material today. Although the prescribing of silicone hydrogel lenses is increasing, millions of lens wearers globally have been wearing hydrogel lenses for many years and exhibit a physiologically-stable ‘quiet eye’, with a low profile of adverse events. Hydrogel lenses are demonstrated to maintain a low inflammatory response and infection risk profile during daily wear, which in the case of etafilcon A, may be related to its low modulus, and the naturally-protective, anti-microbial, non-denatured lysozyme absorbed into the lens from the tear fluid. Although improved corneal physiology from decreased hypoxia with silicone hydrogel lenses is well accepted, equivalent levels of corneal oxygenation are maintained during daily wear of low to medium powered hydrogel lenses, which do not impede the daily corneal de-swelling process, and do not induce clinically significant changes in ocular health. Therefore, hydrogel lenses remain an important alternative for daily wear in modern contact lens practice.     

Predicting Stability of Distiller’s Wet Grains (DWG) with Color Analysis

Distiller’s wet grain (DWG) is one of the coproducts from the fuel ethanol industry. Although many studies have investigated the nutritional properties of DWG, little work has investigated the storability and shelf life for these feed products or how to measure these quantities. The objectives of this research were to measure the development of microorganisms and their respiration over time in freshly produced DWG and to determine if there was a quantitative relationship between these microbiological parameters and a more easily measured physical property, DWG color. The numbers of aerobic heterotrophic bacteria, molds and yeasts, and carbon dioxide generated by microbial respiration were measured at t = 0, 1, 2, 4, and 7 days as were Hunter color (L, a, b) values. All of the microbial parameters increased significantly over time (p < 0.05). Hunter L and a values appeared to change over time as well, but these differences became significant only at t = 7 days; at this time period, Hunter b changed significantly also. Hunter a and b values were negatively correlated with aerobic heterotroph numbers (r = −0.74 for Hunter a; r = −0.77 for Hunter b), yeast and mold counts (r = −0.78 for Hunter a; r = −0.81 for Hunter b), and CO₂ production (r = −0.89 for Hunter a; r = −0.87 for Hunter b). Hunter L values had moderate positive correlations with the microbial parameters (r values ranged from 0.42 to 0.57). Using Hunter a and b color parameters as predictor variables, multiple linear and nonlinear regressions produced R ² values of 0.751, 0.665, and 0.816 for aerobic heterotrophs, molds and yeasts, and CO₂ generation, respectively. Additional research should quantify spoilage criteria, the relationship to palatability, and determine how best to use color changes as indicators of each.     

Children’s liking and intake of vegetables: A school-based intervention study

This study investigated effects on vegetable liking and intake gained from exposing children to snack vegetables of different liking levels. In total, 345 9–11-year-old children participated. The intervention consisted of two exposure periods. First, children were either exposed to a neutrally liked vegetable (cauliflower), a mixture of a neutrally liked and a liked (sugar snap peas) vegetable, or a mixture of a neutrally liked and a disliked (celery) vegetable. In the second, period all children were served all vegetables. Intake of individual vegetables was measured daily. Liking was assessed before and after exposures and at a subsequent follow-up. Liking for most vegetables decreased during the exposure periods but tended to recover somewhat during follow-up. Intake of all vegetables was either stable or decreased during the intervention, no increases were observed. Intake levels depended on type of vegetable servings: When served with a liked vegetable, children consumed more of a neutrally liked vegetable than when served alone (p = 0.0005) or together with a disliked vegetable (p = 0.005).     

Consumers’ associations with wellbeing in a food-related context: A cross-cultural study

Consumers’ perception of wellbeing in a food context can affect food choices and might provide a more holistic evaluation of products than overall liking or healthfulness scores. However, considering that wellbeing is a broad concept which lacks of a unique definition, it is necessary to explore how consumers perceive wellbeing in a food-related context. The present work aims at exploring consumers’ associations with wellbeing in a food-related context, taking into account the views of consumers from five countries: Brazil, France, Portugal, Spain and Uruguay. A total of 755 consumers were asked to complete a questionnaire comprising five open-ended questions about foods and wellbeing. The elicited terms were translated into English, coded and grouped into categories. The frequency of mention of the categories was determined and differences among countries were evaluated. In the five countries wellbeing was mainly associated with calmness, health, happiness, food products, positive emotions and satisfaction with specific aspects of life. The effects of foods on wellbeing were strongly related to physical health, pleasure and emotional aspects. Meanwhile, consumers regarded sensory characteristics, manufacturing processes, nutritional composition and context of food consumption as the main factors underlying food-related wellbeing. Vegetables, fruits, fish and seafood, meat products, grains and cereals, and dairy products were the main foods recognized as positive for wellbeing, whereas foods high in fat, salt and sugar, meat products, junk food and fried food were perceived as harmful. Significant differences among countries were identified in the frequency of mention of the categories elicited in the five questions, suggesting that culture affected consumers’ associations with wellbeing.     

Effect of alkali treatment of lower concentrations on the structure and tensile properties of Pakistan’s coarse cotton fibre

Abstract

Cotton fibres of high Micronaire values are known to have inferior spinning performance. Either reduction of fibres’ fineness or increase in tensile strength is generally expected to improve the spinnability of fibres. In this piece of research, the effects of alkali treatment at lower concentrations (0.75–2.25M) and higher temperatures (70–100?°C) on the cross-section of cotton fibre and on the tensile strength have been investigated. Observations were made using scanning electron microscopy (SEM) and single fibre tensile strength testing. It was found that the roundness of the fibre cross section was improved and the tensile strength of the fibres also increased after treatment with alkali at lower concentration (0.75?M) and relatively lower temperature (70?°C). It is proposed that such changes occurred due to possible cellulose dissolution/transformations. It was thus concluded that the alkali treatment of cotton fibres at lower concentrations (0.75?M) and 70?°C for a shorter period of time (45 mins) could lead to improvement in tensile strength and roundness of fibre cross-section, thereby improving micronaire.