Influence of equibiaxial extensional strain on stress relaxation of glycerol plasticised wheat gluten

BACKGROUND: Glycerol plasticised wheat gluten shows advantages for non-food applications such as biodegradable package films and bioplastics because of their abundant resources, low cost, good biodegradability and suitable mechanical and oxygen barrier properties. The intention of this study was to evaluate to the equibiaxial stress relaxation of 400 g kg(-1) glycerol plasticised gluten at different biaxial strains at room temperature for a better understanding of the processibility. RESULTS: The plasticised gluten shows significant stress relaxation and the spectra span over six decades of time at biaxial strains from 0.03 to 1.51. Plotting the instantaneous modulus against strain reveals strain softening and strain hardening at strains below and above 0.25, respectively. The relaxation modulus as a function of time can be fitted to the Kohlrausch-Williams-Watts equation. CONCLUSION: These results suggest that stress relaxation of plasticised gluten is highly dependent on strain level and biaxial deformation accelerates the network relaxation by widening the distribution of relaxation times. (c) 2008 Society of Chemical Industry

Adaptive Label Allocation for Unsupervised Person Re-Identification

Most unsupervised methods of person re-identification (Re-ID) obtain pseudo-labels through clustering. However, in the process of clustering, the hard quantization loss caused by clustering errors will make the model produce false pseudo-labels. In order to solve this problem, an unsupervised model based on softened labels training method is proposed. The innovation of this method is that the correlation among image features is used to find the reliable positive samples and train them in a smooth manner. To further explore the correlation among image features, some modules are carefully designed in this article. The dynamic adaptive label allocation (DALA) method which generates pseudo-labels of adaptive size according to different metric relationships among features is proposed. The channel attention and transformer architecture (CATA) auxiliary module is designed, which, associated with convolutional neural network (CNN), functioned as the feature extractor of the model aimed to capture long range dependencies and acquire more distinguishable features. The proposed model is evaluated on the Market-1501 and the DukeMTMC-reID. The experimental results of the proposed method achieve 60.8 mAP on Market-1501 and 49.6 mAP on DukeMTMC-reID respectively, which outperform most state-of-the-art models in fully unsupervised Re-ID task

Microrheology of magnetorheological silicone elastomers during curing process under the presence of magnetic field

A microrheological method is employed for the first time to continuously and undisturbedly monitor variations of viscoelasticity of magnetorheological elastomers (MREs) based on silica-coated carbonyl iron particles (SiCIPs)-filled silicone during the curing process. Results indicate that the elasticity of MREs dramatically increases with increasing magnetic field intensity, which is much more significant in comparison with the slow process of silicone curing at 25 % and 40 % SiCIPs. The formations of chain-like structure of SiCIPs and cured network of silicone are recognized, both contributing to the rheology of MREs, suggesting the possibility of developing a facile method for adjusting the rheology and fixing the structure of a wide range of MREs by applying magnetic field during the curing of matrix

Adaptive Label Allocation for Unsupervised Person Re-Identification

Most unsupervised methods of person re-identification (Re-ID) obtain pseudo-labels through clustering. However, in the process of clustering, the hard quantization loss caused by clustering errors will make the model produce false pseudo-labels. In order to solve this problem, an unsupervised model based on softened labels training method is proposed. The innovation of this method is that the correlation among image features is used to find the reliable positive samples and train them in a smooth manner. To further explore the correlation among image features, some modules are carefully designed in this article. The dynamic adaptive label allocation (DALA) method which generates pseudo-labels of adaptive size according to different metric relationships among features is proposed. The channel attention and transformer architecture (CATA) auxiliary module is designed, which, associated with convolutional neural network (CNN), functioned as the feature extractor of the model aimed to capture long range dependencies and acquire more distinguishable features. The proposed model is evaluated on the Market-1501 and the DukeMTMC-reID. The experimental results of the proposed method achieve 60.8 mAP on Market-1501 and 49.6 mAP on DukeMTMC-reID respectively, which outperform most state-of-the-art models in fully unsupervised Re-ID task

Effect of Hydrogen Bonding on Dynamic Rheological Behavior of PVA Aqueous Solution

The rheological behavior of polyvinyl alcohol (PVA) aqueous solution is crucial to optimizing the processing technology and performance of PVA products. In this paper, the dynamic rheological behavior of PVA aqueous solution was investigated in detail. PVA solution with a concentration of 10 wt% showed unnormal rheological behaviors, that is, the liquid-like behavior in the high frequency (ω) region and the solid-like behavior in the low ω region. A storage modulus (G′) plateau appears in the relatively low ω region as a gel with a network structure. Different from conventional hydrogel, this plateau has a low modulus, and the corresponding size of the relaxation unit is estimated to be 554 nm, being higher than the size of a whole PVA chain. It is believed that the network mesh is formed by the intermolecular hydrogen bonding interactions among PVA chains. The relaxation time of these meshes is longer than the reptation time of a PVA chain. Based on the relaxation spectrum and calculation analysis, it is found that the destruction of intermolecular hydrogen bonds, such as by heating up, adding sodium dodecyl sulfate, and shear operation, will make the relaxation unit (mesh) larger and lead to the left shift of the intersection of G′ and loss modulus (G″). In a PVA solution with a high concentration, multiple meshes of various sizes could be formed and thus generate multiple relaxation peaks. The large-sized meshes mainly contribute to the left shift of the intersection of G′ and G″, and the small-sized meshes contribute to the high plateau modulus. The results in this paper offer a new angle to analyze polymer solutions with strong intermolecular interaction

Enhanced toughness of PLLA/PCL blends using poly(d-lactide)-poly(ε-caprolactone)-poly(d-lactide) as compatibilizer

Poly(l-lactide) (PLLA)/poly(ε-caprolactone) (PCL) blends traditionally show low ductility because of the immiscibility between PLLA and PCL. In this study, this ductility challenge was addressed by modifying the compatibility between PLLA and PCL using poly(d-lactide)-poly(ε-caprolactone)-poly(d-lactide) (PDLA-PCL-PDLA or PCDL) tri-block copolymer. PLLA/PCL and PLLA/PCL blends with 0.7 phr and 3.5 phr PCDL were prepared by melt-compounding and extrusion and analyzed. The compatibilized PLLA/PCL blend with 3.5 phr of PCDL exhibited an elongation-at-break of 43%, compared to 18% in uncompatibilized PLLA/PCL, although PLLA/PCL/PCDL3.5 showed the higher crystallinity of 10.0% compared to 3.1% in PLLA baseline. The stereocomplexation effect between PLLA and PDLA was confirmed with a melting peak of a stereocomplex crystallite at 212 °C through differential scanning calorimetry. PCDL compatibilization improved miscibility between PLLA and PCL as evidenced through the interfacial morphology analysis, and supported by the rheological analysis, which elucidated the enhanced melting viscosity and interfacial adhesion of PLLA/PCL. Overall, the compatibilization of PLLA/PCL blends with PCDL was effective in achieving an enhanced interfacial morphology and adhesion, and improved elongation-at-break