Methodology for dependence-based integrated constitutive modelling: An illustrative application to SiCp/Al composites

In industrial forming and machining process, the large plastic deformation of material takes place in wide loading ranges of strain-rate and forming temperature. A satisfactory modelling of quasi-static and dynamic material behaviors is of great importance for understanding physical process and processes optimization. A dependence-based integrated methodology, together with an improved weighted multi-objective parameter identification strategy is presented for the development of phenomenological constitutive model and the parameter identification using experimental data from quasi-static and dynamic tests with instantaneous strain rate variations and plastic strain-related temperature changes. The improved multi-objective parameter identification model is reformulated by introducing three weighting factors for valuing different measure errors and fit standard errors in individual objective function corresponding to each test, considering the sampling point number and active material parameter number under different loading conditions, and balancing optimization opportunity of quasi-static and dynamic sub-objective functions. The methodology is verified for feasibility through illustrative constitutive identification for SiC_p/Al composites. This may provide a methodology of constitutive modelling for predicting material behaviors in quasi-static and dynamic modes equally well.     

Minimization of the Theoretical Error of Input Parameters for a Vapor Permeation Apparatus

All input experimental errors for membrane flux determination were analyzed. The overall error in pressure did not largely influence the determination of membrane flux. The main contribution to errors was ascribed to flow meters and membrane thickness. The choice of an optimal operational range for input parameters led to elimination of at least 2/3 of the theoretical relative error for subsequent evaluation of the permeability of individual species. This is especially valuable for low‐permeable membranes, whereas a very low relative theoretical error can be obtained in the case of highly permeable materials.     

Optimal parameter estimation for PEMFC using modified monarch butterfly optimization

The present study develops a new optimization method called monarch butterfly optimization algorithm for optimal parameter estimation of the polymer electrolyte membrane fuel cell (PEMFC). After designing the proposed methodology, it is implemented to 250 MW PEMFC stack under different operating conditions to show the system efficiency and the results are compared with some state-of-the-art methods including Grass Fibrous Root Optimization Algorithm, hybrid Teaching Learning Based Optimization-Differential Evolution Algorithm, and the basic MBO algorithm. Two operational conditions in 3/5 bar and 80°C and 2.5/3 bar, 70°C are used for model verification. The main idea is to minimize the sum of square error (SSE) between the estimated and the actual data. Simulation results in the first condition give an SSE of value 7.277667729 with 9.28434e−16 SD value and in the second condition, an SSE of value 4.52810115 with 0.043581628 standard deviations has been reached as the minimum value among the other compared methods that indicate the accuracy and the robustness of the suggested method toward the analyzed methods. The algorithm also gives a convergence speed of 540 iterations and 370 iterations for conditions 1 and 2, respectively that are the fastest in the study.     

Identification of hydrogen permeability parameters of membrane materials in an aggregated experiment

The study of the hydrogen permeability of materials for membrane-based separation/purification technologies employs a variety of experimental methods with their own specific features, advantages and shortfalls. The method of penetration with vacuum pumping allows determining the diffusion coefficient from so-called lag time. The accuracy of the estimation depends on the degree of proximity to the DLR (diffusion limited regime) mode. The method of “communicating vessels” is more sensitive to surface processes. The thermal desorption (TDS) technique permits “scanning” the material dynamically across a wide range of temperatures. “Separate” application of these methods leads to a situation where the materials studied are in fact somewhat different (for example, due to different impacts on the surface), and significant differences in parameter estimates ensue. This paper suggests and implements a technique for a combined three-stage ‹‹penetration (with and without vacuum pumping)+TDS›› experiment and the corresponding mathematical toolkit. The informative capacity of the experiments and the accuracy of the estimation of hydrogen permeability parameters (adsorption, dissolution, diffusion and desorption) of the membrane materials under study are thus enhanced.     

综掘设备人员识别预警系统

为解决煤矿井下综合掘进设备由于视野盲区造成的后部输送机摆动误伤行人的安全问题,以红外成像和图像处理技术为基础,设计出一种适用于井下综掘设备的人员识别预警系统。系统采用模块化设计和集成封装,在连续采煤机上进行应用测试并进行结构优化,测试证明系统识别精度高,响应迅速,能够准确识别综掘设备危险区域内的行人,并实现危险区域外2 m范围内的人员预警及1 m范围1 s内的中断停机操作。     

自动矿物学：Ⅰ. 技术进展与应用

近年来，“自动矿物学”（或“定量矿物学”）的概念和相关技术得到了显著的发展和广泛的应用，使矿物学研究，尤其是工艺矿物学研究从人工测试走向自动化测试、从定性研究走向定量研究。本文评述了自动矿物学的技术进展与应用，主要包括：①矿物分析技术发展阶段；②自动矿物学技术国际研究进展与国内研究现状；③自动矿物学的应用领域及发展趋势。在此基础上，总结了基于扫描电镜的自动矿物学技术的基本原理以及选矿产品环氧树脂抛光片制备过程中需要注意的一些问题。以期为固体地球科学研究和矿产资源开发利用过程中遇到的一些瓶颈问题提供新的研究途径和新的思路。     

Efficient model selection for real-time adaptive cold start strategy of a fuel cell system on vehicular applications

The PEMFC maximum power is greatly influenced by subfreezing temperature and degradation phenomena. Therefore, a dependable model is required to estimate the power with respect to the variation of the operating conditions and state of health. Semi-empirical models are potent tools in this regard. Nonetheless, there is not much information about their cold environment reliability. This paper comprehensively compares the performance of some models (already tested in normal ambient temperature) in subfreezing condition to introduce the most reliable one for PEMFC cold start-up application. Firstly, seven models are compared regarding voltage losses and precision. Subsequently, the three most dependable ones are selected and experimentally compared at sub-zero temperature in terms of polarization curve estimation for three PEMFCs with different degradation levels. The results of this study indicate that the model introduced by Amphlett et al. has a superior performance compared to other ones regarding the characteristic's estimation in below-zero temperature.     

蓝莓溃疡病生防链霉菌CX3的抑菌效果及其鉴定

[目的]为了明确从吉林省长白山保护区池西保护站马鞍山云杉人工林林下土壤分离,所获得1株拮抗菌株(编号记为CX3)的生防效果及分类地位。[方法]分别采用平板对峙法和杯碟法测定该菌株活菌及其发酵液的抑菌活性和抑菌谱;并通过形态学、生理生化特征、16S rRNA序列分析等方法研究了其分类地位。[结果]该菌株对13种供试植物病原菌均有抑制作用,抑菌谱广,其中对蓝莓溃疡病菌有极强的抑制作用,抑菌带达25.91 mm,发酵液的抑菌圈直径达31.73 mm;根据其菌株形态、生理生化特性、16S rRNA序列比对,最终鉴定菌株为链霉菌属Streptomyces sp.。[结论]该菌株对蓝莓溃疡病菌有显著的抑制效果,应用开发前景良好,此次是国内首次报道该菌株杀真菌活性。     

爆破工程安全评价初探

开展爆破工程安全评价可有效地减少各种危险和有害因素 ,减少爆破事故的发生 ,大型或特殊爆破工程均应进行安全评价。本文提出了对爆破工程开展安全评价的设想 ,并对爆破工程安全评价的内容和方法进行了探讨。文中指出 :根据爆破工程的特点 ,可采用事故树分析和预先危险性分析等方法进行爆破工程的安全评价