The effect of UV degradation on the recovery behavior of cut-pile carpets after static loading

UV exposure is a major source of degradation and deterioration of textile materials including carpets. Samples of machine-woven cut-pile carpets were prepared and exposed to different UV exposure times using a UV chamber. The short-term static loading was then applied to the carpets and the recovery properties and the thickness loss of the samples were measured using standard methods. The results showed that the variation of the thickness loss in different load removal times was steep at first and obeyed an exponential trend. As the time was increased, it tended to a lower slope and at a certain point, it reached a constant value. No statistically significance difference was observed in the thickness losses following 60 min of load removal time after static loading. UV radiation caused a significant increase in the thickness loss, or compression of piles, under static loading. Curve fitting process was applied and then the theoretical recovery speed equation was predicted. The results revealed that the compression of the carpets under static loading was higher in the case of UV exposure carpets. However, the speed of the recovery after load removal was much higher in the case of UV exposure carpets, in comparison to the non-exposure carpets.     

Analysis of the effect of traffic exposure on the recovery properties of cut pile carpet using analytical and viscoelastic modeling

Viscoelastic models composing of different combination of spring and dashpot are usually used to explain the mechanical behavior of textile materials. In this work, a viscoelastic model was presented to analyze the effect of traffic exposure on the compression and recovery performance of the pile carpet. Wear test, performed by a Hexapod tumbling machine, was conducted to simulate the traffic exposure. Using a tensile tester, adjusted in compression mode, one cycle of compression–decompression was applied to the samples. The standard nonlinear model was presented to fit the experimental data. Best curve fitting based on the least square method was then used to fit the model to the experimental curve. Different attributions of compression were then analyzed and discussed. The results showed that the standard nonlinear model was fitted to the experimental curves with an acceptable coefficient of regression (R²). The district model parameters, i.e. the spring and dashpot constants, were both decreased as the wear cycles increased. At the higher level of wear cycles, the model parameters showed some increment. The initial compression modulus showed the same trend. This may be explained by the more compactness of the carpet at higher wear cycles. The decompression modulus, compression and the decompression work also decreased with the increase of wear cycles. However, no significant increase of the formers was observed at the higher wear cycles.     

Prediction of the thickness loss and recovery of cut-pile carpets imposed to UV exposure and wear using polynomial regression method

Ultraviolet radiation which exists in environment around can be regarded as a major source of textile materials. In this study, the effect of UV exposure on the cut-pile carpet was investigated. A UV chamber was used to expose different levels of accelerated UV radiation on the samples of the machine-woven pile carpet. Wear test were then carried out on all samples using a Hexapod tumbler machine. The short-term static loading was applied to the carpets and the thickness loss percent (TL) and recovery percent (RP) of the samples at different times after load removal was measured using standard methods. Factorial experimental design and response surface method were applied for to create polynomial regression models and predict each of the thickness loss and recovery percent of carpet samples. The model is capable to determine the contribution of different variables. The results of the modeling revealed a desirable fit. The adjusted R² values were also high and significant. The ANOVA test indicated that the presented models were valid at 5% significant level.     

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.     

紫外和超高压诱导漆酶产生菌变异的对比研究

分别利用紫外线和超高压诱变漆酶产生菌灵芝(Ganoderma.lucidum Karst),发现超高压的诱变幅度较大.经初步筛选和发酵,获得了2株具有较大应用潜力的漆酶超高压突变株G1502和G2001,前者漆酶活力比出发菌株提高了2.83倍,发酵时间缩短了1 d;后者漆酶活力提高了0.89倍,发酵时间缩短了3 d.     

The effect of cyclic loading on the mechanical properties of artificial ligaments

In this study, artificial anterior cruciate ligaments (ACLs) were manufactured using braiding and knitting processes. These artificial ligaments were designed to match the mechanical requirements of a native human ACL, including the fatigue performance. The effect of cyclic loading on the mechanical performance of the artificial ligaments was studied at different deformation rates (slow: 2% per second, medium: 50% per second and fast: 100% per second). The primary results showed that the deformation rate had no significant effect on the ultimate tensile strength, strain or stiffness. Single tensile loading to failure performed for each prosthesis before and after cyclic loading allowed the determination of its effect on the mechanical performance of the artificial ligaments. The increase in the number of cycles decreased the maximum strain and the ultimate tensile strength but had no significant effect on the stiffness. At 60,000th cycle, the braided prosthesis presented a better performance with a lower residual deformation compared with the knitted prosthesis.     

Understanding the influence of fibre,yarn and fabric parameters on UV protection of wool-knitted fabrics

This work investigated the influence of fibre, yarn and fabric parameters on the UV protection of fabrics. It proposed a model for UV interaction based on a theoretical hypothesis, targeted experimentation and statistical analysis. Undyed and untreated wool-knitted fabrics with varying mean fibre diameter, yarn linear density, yarn twist, fabric cover factor and fabric structure were examined. A statistical model was presented to report the relationship between fibre/yarn/fabric parameters and fabric UPF values. An optical model on the interaction between the UV light and a single jersey fabric was constructed to understand the penetration of UV light. The models were verified by the UV transmittance results of knitted wool fabrics. The results obtained from the statistical and optical models were used to propose a set of optimized parameters for lightweight summer/spring UV-protective knitted fabrics. Testing confirmed that these fabric parameters provided both high UV protection and good tactile comfort.     

A study on relationships between durum wheat semolina properties,technological mixing parameters and the properties of dough after mixing

Partial least square regression analysis was used to study the correlation between X variables (semolina quality, hydration level and mixing time) and Y variables, which were, in a first model, dough consistency during mixing, and, in a second model, dough properties after mixing (strength, elasticity, density) and leavening (maximum volume). The first model showed a predictive residual sum of squares (PRESS) of 2.98 and a predictive R² (Q²) of 0.92, and highlighted the key role of hydration and mixing time on dough consistency. The second model had the best PRESS (8.25) and Q² (0.94) values for dough volume and indicated that the volume increased with increasing mixing time until the dough consistency decreased of 20–30%. Dough volume was primarily affected by hydration. The model indicated that maximum volume after leavening, corresponding to optimum mixing time, was obtained with a soft and elastic dough, with a low‐density value.     

Modeling the effect of elastane linear density,fabric thread density,and weave float on the stretch,recovery, and compression properties of bi-stretch woven fabrics for compression garments

The aim of this study was to investigate the effect of elastane linear density, thread density, and weave float on the stretch, recovery, and compression properties of bi-stretch woven fabrics for compression garments. Fabric samples were produced using elastane core-spun cotton yarns both in the warp and weft. The elastane linear density, fabric thread density, and weave float size were used as input variables while fabric contraction, subgarment pressure, fabric stretch, and recovery were taken as response variables. Two different elastane linear densities, i.e. 44 and 78 dtex, two different thread densities, and three different weave designs, i.e. 1/1 plain, 2/2 z-twill, and 3/3 z-twill were used. The results of fabric samples were analyzed in Minitab statistical software. The coefficients of determinations (R-sq values) of the regression equations showed good prediction ability of the developed statistical models. The findings of the study may be helpful in deciding appropriate manufacturing specifications of bi-stretch fabrics to attain specific stretch, recovery, and compression properties.