This study proposed a crystallographic texture-based multi-scale modelling framework to predict mechanical anisotropy of textured aluminium alloy sheet. The multi-scale scheme was constructed by the ...combination of a full-field crystal plasticity model in mesoscopic scale and a newly developed phenomenological yield function in continuum scale. In this approach, the mechanical anisotropy of materials is directly obtained from crystal plasticity (CP) modelling without extensive directional tensile tests. The results show that the multi-scale scheme predicted earing profiles coincide well with experimental measurements. This multi-scale modelling could be utilised to design an optimised blank shape with minimum earing for the deep-drawn component, and a convoluted cut-edge was devised accordingly.
An LSSA-BP neural network prediction model was established for more accurate onshore wind power cost prediction. Optimise the weights and thresholds of the BP neural network using the sparrow search ...algorithm. Comparison of the traditional BP model, GA-BP model and LSSA-BP model to verify the superiority of the LSSA-optimised BP model. Moreover, using LSSA-BP in compared with Support Vector Regression Forecasting (SVR) and Random Forest Regression Forecasting (RFR) models. The results of model trial calculations and analysis showed that the LSSA-BP model had the highest prediction accuracy and could be used as a reference for the onshore wind power cost prediction.
This paper proposed a hierarchical multi-level model to study the crystallographic texture induced mechanical anisotropy of AA3104-H19 aluminium sheet from mesoscale to continuum scale. In the ...mesoscale, full-field crystal plasticity finite element method (CPFEM) was used to provide both in-plane and out-of-plane yield stresses and plastic potential points in various deformation modes. In the continuum scale, these materials sampling points were used to determine the parameters of two phenomenological yield functions (Yld2000-2d in plane stress space and Yld2004-18p in 3D stress space) using associated flow rule (AFR) and non-associated flow rule (non-AFR). The results indicate that higher accuracy obtained by Yld2000-2d and Yld2004-18p yield functions associated with non-AFR in comparison with AFR. These phenomenological models were successfully implemented into finite element (FE) code using an explicit integration scheme to simulate sheet metal forming. It is found that the 3D Yld2004-18p model involved with both in-plane and out-of-plane anisotropies is superior to 2D Yld2000-2d model which only accounts for in-plane anisotropy.
Microglia have been shown to contribute to the clearance of brain amyloid β peptides (Aβ), the major component of amyloid plaques, in Alzheimer's disease (AD). However, it is not known whether ...microglia play a similar role in the clearance of tau, the major component of neurofibrillary tangles (NFTs). We now report that murine microglia rapidly internalize and degrade hyperphosphorylated pathological tau isolated from AD brain tissue in a time-dependent manner in vitro. We further demonstrate that microglia readily degrade human tau species released from AD brain sections and eliminate NFTs from brain sections of P301S tauopathy mice. The anti-tau monoclonal antibody MC1 enhances microglia-mediated tau degradation in an Fc-dependent manner. Our data identify a potential role for microglia in the degradation and clearance of pathological tau species in brain and provide a mechanism explaining the potential therapeutic actions of passively administered anti-tau monoclonal antibodies.
This study provides a novel methodology to evaluate fatigue life with the consideration of both confidence level and reliability for CFRP laminates by combining fracture fatigue entropy (FFE) theory ...and knowledge of statistics. After carrying out distribution analysis and statistical hypothesis testing, it is found that the FFEs obey well to log-normal distribution and the average values and deviations of logarithmic FFEs under different stress levels exhibit no obvious difference. The γ-p-S-N curves are predicted by single side allowance factor analysis and the prediction is found to be more conservative and have a larger scatter comparing to experimental results.
•The correlation coefficients show FFE data obey well to log-normal distribution.•The FFE values under different stress levels exhibit no obvious different.•A new method based on statistical analysis is developed to predict p-r-S-N curves.•The predicted p-r-S-N curves are conservative comparing to experimental ones.
A new anisotropic yield function which accurately describes the complex anisotropy of aluminium alloy sheet metal is proposed in this paper. A non-linear least square method is used to determine the ...coefficients of this yield function based on the experimental results. By employing the back-Euler stress integration algorithm, this anisotropic constitutive model has been successfully implemented in commercial FEM software ABAQUS via user material subroutine UMAT to predict earing profile of AA3104-H19 deep-drawn and redrawn cups. Good agreement was found in the predicted earing profiles and those obtained in experimental deep-drawn and redrawn cups. The FE model was used in an iteration optimisation process to determine the optimal shape of non-round blanks to obtain the ear-free deep-redrawn cups, and non-round tooling was designed accordingly. Results showed the height of the ears is significantly reduced in the cup formed using this non-round blank compared with that of a conventional round blank which is important for smooth running of high-speed multi-step forming of aluminium can body.
Axial and hoop stiffness can describe the elastic responses of reinforced thermoplastic pipes (RTPs) subjected to axisymmetric loads, such as tension, compression, pressure, and crushing loads. ...However, an accurate analytical prediction cannot be provided because of the anisotropy of RTP laminates. In the present study, a stiffness surface method, in which the analytical expressions of the axial and hoop stiffness are derived as two concise formulas, is proposed. The axial stiffness formula is obtained by solving the equilibrium equations of RTPs under a uniaxial stress state based on the homogenization assumption, whereas the hoop stiffness formula is derived from the combination of the elastic stability theory, the classical lamination theory, and NASA SP-8007 formula. To verify the proposed method, three types of RTPs are modeled to conduct the quasi-static analyses of the tension and crushing cases. The consistency between numerical and analytical results verifies the effectiveness of the proposed method on the prediction of the axial and hoop stiffness of RTPs, which also proves the existence of stiffness surfaces. As the axial stiffness is proportional to the radii, the axial stiffness surface consists of a series of straight lines, which can be used to predict both thin-walled and thick-walled RTPs. Meanwhile, the hoop stiffness is more applicable for thin-walled RTPs because the proposed method ignores the proportional relationship between the homogenized hoop elastic moduli and the reciprocal radii in helical structures.
Here, we report the generation and characterization of a novel Huntington's disease (HD) mouse model BAC226Q by using a bacterial artificial chromosome (BAC) system, expressing full-length human HTT ...with ~226 CAG-CAA repeats and containing endogenous human HTT promoter and regulatory elements. BAC226Q recapitulated a full-spectrum of age-dependent and progressive HD-like phenotypes without unwanted and erroneous phenotypes. BAC226Q mice developed normally, and gradually exhibited HD-like psychiatric and cognitive phenotypes at 2 months. From 3 to 4 months, BAC226Q mice showed robust progressive motor deficits. At 11 months, BAC226Q mice showed significant reduced life span, gradual weight loss and exhibited neuropathology including significant brain atrophy specific to striatum and cortex, striatal neuronal death, widespread huntingtin inclusions, and reactive pathology. Therefore, the novel BAC226Q mouse accurately recapitulating robust, age-dependent, progressive HD-like phenotypes will be a valuable tool for studying disease mechanisms, identifying biomarkers, and testing gene-targeting therapeutic approaches for HD.
Phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1) and PARK2/Parkin mutations cause autosomal recessive forms of Parkinson's disease. Upon a loss of mitochondrial membrane ...potential ( $\Delta \Psi _m$ ) in human cells, cytosolic Parkin has been reported to be recruited to mitochondria, which is followed by a stimulation of mitochondrial autophagy. Here, we show that the relocation of Parkin to mitochondria induced by a collapse of $\Delta \Psi _m$ relies on PINK1 expression and that overexpression of WT but not of mutated PINK1 causes Parkin translocation to mitochondria, even in cells with normal $\Delta \Psi _m$ We also show that once at the mitochondria. Parkin is in close proximity to PINK1, but we find no evidence that Parkin catalyzes PINK1 ubiquitinationorthatPINKI phosphorylates Parkin. However, co-overexpression of Parkin and PINK1 collapses the normal tubular mitochondrial network into mitochondrial aggregates and/or large perinuclear clusters, many of which are surrounded by autophagic vacuoles. Our results suggest that Parkin, together with PINK1, modulates mitochondrial trafficking, especially to the perinuclear region, a subcellular area associated with autophagy. Thus by impairing this process, mutations in either Parkin or PINK1 may alter mitochondrial turnover which, in turn, may cause the accumulation of defective mitochondria and, ultimately, neurodegeneration in Parkinson's disease.
This paper deals with the problems of finite-time boundedness (FTB) and H∞ FTB for time-delay Markovian jump systems with a partially unknown transition rate. First of all, sufficient conditions are ...provided, ensuring the FTB and H∞ FTB of systems given by linear matrix inequalities (LMIs). A new type of partially delay-dependent controller (PDDC) is designed so that the resulting closed-loop systems are finite-time bounded and satisfy a given H∞ disturbance attenuation level. The PDDC contains both non-time-delay and time-delay states, though not happening at the same time, which is related to the probability distribution of the Bernoulli variable. Furthermore, the PDDC is extended to two other cases; one does not contain the Bernoulli variable, and the other experiences a disordering phenomenon. Finally, three numerical examples are used to show the effectiveness of the proposed approaches.
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