Differential scanning calorimetry, x-ray diffraction, and polarized optical microscopy were used to investigate the quiescent crystallization and melting behavior of isotactic polypropylene (iPP) nanocomposites based on synthetic organic-soluble Ag nanocrystals (NCs). The effects of Ag loading and crystallization temperature on the crystallization behavior and crystalline structure were studied. The results showed that the synthetic Ag NCs as a novel effective β-crystal nucleating agent for iPP could promote the overall crystallinity, decrease the size of spherulites, and induce the formation of large amounts of β-crystals in the nanocomposites under quiescent crystallization. The relative content of β-crystals significantly increased with increasing Ag loading, and slightly increased with decreasing crystallization temperature. The quiescent crystallization kinetics was analyzed using the Avrami model. The results showed that the iPP nanocomposites with added Ag NCs had higher crystallization rate constant (k) and lower crystallization half-times (t1/2) as well as the Avrami exponent (n) than pure iPP, indicating that the presence of Ag NCs acted as heterogeneous nucleating sites and promoted the crystallization rate of iPP.
Two-dimensional (2D) and three-dimensional (3D) computer-aided design and manufacture (CAD/CAM) are extensively applied in the fashion industry to increase efficiency and save time and labour cost. Two of the drivers for re-engineering the current manufacturing approach of sportswear are to reduce material waste and to improve the comfort of sports bras. This research bridges the 3D anthropometry with technical 3D seamless weaving techniques exploiting cross-platform software technology—3D reverse engineering system, 2D CAD clothing system and textile CAD/CAM system—to develop seamless woven sports bra cups. The flattened 2D geometry pattern, obtained with segmentations and artificial boundary lines, was used in the weaving process, and the final woven sample proved the geometric and digital methodological feasibility.
The nonisothermal crystallization behaviors for poly(ethylene 2,6‐naphthalate) (PEN) and poly(ethylene 2,6‐naphthalate) (PEN)/montmorillonite nanocomposites prepared by melt intercalation were investigated using differential scanning calorimetry (DSC). The Jeziorny, Ozawa, Ziabicki, and Kissinger models were used to analyze the experimental data. Both the Jeziorny and the Ozawa models were found to describe the nonisothermal crystallization processes of PEN and PEN/montmorillonite nanocomposites fairly well. The results obtained from the Jeziorny and the Ozawa analysis show that the montmorillonite nanoparticles dispersed into PEN matrix act as heterogeneous nuclei for PEN and enhance its crystallization rate, accelerating the crystallization, but a high‐loading of montmorillonites restrain the crystal growth of PEN. The analysis results from the Ziabicki and the Kissinger models further verify the dual actions stated above of the montmorillonite nanoparticles in PEN matrix.
Anthropometric data form the cornerstone of garment pattern-making. This article introduces an artificial intelligence-driven approach, employing a back-propagation artificial neural network (BP-ANN), to predict the anthropometric data essential for crafting patterns for women's upper tops. The model adeptly processes minimal critical data from women's upper bodies, yielding projected dimensions that are arduous to manually measure yet crucial for tailoring body-fitting tops. Utilising a three-dimensional body scanner for accurate anthropometric data collection from 196 women in Sichuan Province, China, our study compares the BP-ANN model with a Linear Regression (LR) model. Results demonstrate superior predictive accuracy for BP-ANN. Notably, the BP-ANN model excels in efficiency and accuracy, particularly in challenging anthropometric parameters. The findings underscore the transformative potential of AI-based models in optimizing garment production processes, offering a precise alternative to traditional methods. This research contributes valuable insights for the integration of AI technology in advancing pattern-making practices.
The crystallization behavior of poly(ethylene terephthalate) (PET)/poly(ethylene‐ 2,6‐naphthalate) (PEN) blends before and after microwave irradiation for different time intervals has been investigated by means of wide angle X‐ray diffraction (WAXD) and differential scanning calorimetry (DSC) techniques. It was found that microwave irradiation could greatly affect the crystallization behavior of PET/PEN blends and significantly enhance their degree of crystallinity. For the PET/PEN (90/10) blends, the degree of crystallinity increased from 15 to 45%; for the PET/PEN (60/40) blends, the degree of crystallinity significantly increased, from 1 to 36%. However, with increasing irradiation time, the degree of crystallinity didn't continually increase. It reached a maximum at certain time point. The cold crystallization enthalpy △Hcc gradually decreased as microwave irradiation time increased and the melting enthalpy △Hm vis‐à‐vis the long time interval of such irradiation was decreased. In addition, the mechanism for microwave irradiation affecting the crystallization behavior of polymers is discussed.
Organic-soluble Ag nanocrystals (NCs) with tunable sizes in the range from 5.4 to 22.1 nm were synthesized by a facile, reproducible and easily scaled up route using water as solvent in the presence of oleic acid and an alkylamine. The synthetic Ag NCs exhibits excellent hydrophobicity and can be well re-dispersed in various non- or weak-polar media. The tunable sizes of the Ag NCs were achieved by simply adjusting the initial precursor AgNO3 concentration. Large-scale synthesis of the Ag NCs was realized at a high AgNO3 concentration (0.4 mol/L). As much as 16.2 g highly uniform organic-soluble Ag NCs with 5 nm average diameter can be readily synthesized at low cost in a single reaction only using 400 mL water as solvent, which is adaptable to the industrial scale production. The structure of the obtained Ag NCs was investigated in detail by X-ray diffractometry, transmission electron microscopy, Fourier transform infrared and thermal gravimetric analysis measurements. The results reveal that the surface of the organic-soluble Ag NCs is coated with the monolayer surfactants consisting of oleic acid and the alkylamine. In addition, on the basis of the sufficient evidences, a proposed mechanism based on the "bilayer surfactant-controlled reaction" successfully demonstrates the formation of high quality organic-soluble Ag NCs in the aqueous solution.
The effects of addition of synthesized organic-suspension silver nanoparticles on the crystallization and thermal stability of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were studied by transmission electron microscopy (TEM), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (XRD), UV-Vis absorption spectroscopy, polarized optical microscopy (POM), and thermal gravimetric analysis (TGA). The TEM images showed the average primary size of the as-synthesized silver nanoparticles, coated with a monolayer of the surfactants consisting of oleic acid and an alkylamine, was about 5 nm with narrow distribution, and that they were uniformly dispersed in n-heptane. PHBV/silver nanocomposites were prepared by melt mixing in an internal mixer and then injection molded into rectangle-shaped specimens by a labscale injection molding device. The coated silver nanoparticles showed a homogenuous dispersion in the PHBV matrix when the content of coated silver nanoparticles was about 1%. Both the DSC and POM data showed the efficient heterogeneous nucleation by the coated silver nanoparticles for facilitating PHBV crystallization. The thermal stability of the PHBV/silver nanocomposites improved with the increase in the content of the coated silver nanoparticles.
An investigation was conducted to estimate the effectiveness of air bags as a function of velocity. The study consisted of three parts: a theoretical idealization, an analysis of National Automotive Sampling System/Crashworthiness Data System (NASS/CDS), and a reanalysis of previously published Fatality Analysis Reporting System (FARS) data. The theoretical analysis looked at idealized risk curves as a function of velocity; assuming that the air bag offers a benefit for both belted and unbelted occupants. Analysis of the NASS/CDS data looked at the effectiveness of air bags as a function of velocity for Maximum Abbreviated Injury Scale (MAIS) 3+ injuries. The reanalysis of the previously published FARS data looked at the effectiveness of the air bag as a function of velocity for fatalities. The theoretical analysis indicates that the air bag effectiveness should be greatest at the low velocities. The field data analysis of both NASS/CDS and FARS were consistent with the theoretical analysis, indicating that air bags are most effective at the lower velocities, below 40 kph (25 mph), for both belted and unbelted occupants. Although it was not possible to estimate a different effect for belted and unbelted for fatalities using FARS, it was possible for MAIS 3+ using NASS/CDS. For unbelted occupants the effectiveness goes to zero or becomes negative above 40 kph (25 mph) for MAIS 3+, and for belted occupants the effectiveness stays positive but with significantly lower magnitude for speeds above 40 kph (25 mph).
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