Experimental study of the burner for FAA fire test: NexGen burner

The NexGen (Sonic) burner is the new burner developed by the Federal Aviation Administration, FAA, to replace old oil burners used for the required fire certification tests on power plant‐related materials, as it provides the capability to control both air and fuel flow rates. During a fire test, the burner is supposed to simulate a certain fire condition, so the flame properties should be robust and repeatable. The NexGen burner can achieve this due to the precise fuel and air controls. However, the current calibration criterion (ISO2685:1998 and AC20‐135) may not be good enough to ensure consistent flame properties. In the presented work, the sensitivity of the burner performance to air and fuel flow rate, as measured by the temperature and heat flux for calibration purposes, was studied. Additionally, the influence of the turbulator and the thermocouple size used for flame calibration was also studied. The impact of varying fuel/air ratio and thermocouple sizes was studied by conducting fire tests on aluminum samples, to show the inadequacies in the current calibration standards.     

黑龙江省农垦建三江管理局区域农业水资源系统恢复力研究

为研究黑龙江省农垦建三江管理局区域农业水资源系统恢复力,运用可变模糊优选模型研究了其下属15个农场的水资源系统恢复力,分析了水资源、社会、经济以及生态环境四个子系统对农业水资源系统恢复力的影响机制,并利用ArcGIS绘制农业水资源系统恢复力等级空间分布图。结果显示建三江管理局农业水资源系统恢复力自西南向东北逐渐增强;其中洪河农场农业水资源系统恢复力最强,勤得利农场次之,创业、前锋、二道河、浓江农场农业水资源系统恢复力一般,其余9个农场农业水资源系统恢复力最弱。研究结果对建三江管理局农业水资源的可持续利用具有重要意义。     

Development of an experimentally validated semi-empirical fully-coupled performance model of a PEM electrolysis cell with a 3-D structured porous transport layer

A semi-empirical non-isothermal model incorporating coupled momentum, heat and mass transport phenomena for predicting the performance of a proton exchange membrane (PEM) water electrolysis cell operating without flow channels is presented. Model input parameters such as electro-kinetics properties and mean pore size of the porous transport layer (PTL) were determined by rotating disc electrode and capillary flow porometry, respectively. This is the first report of a semi-empirical fully coupled model which allows one to quantify and investigate the effect of the gas phase and bubble coverage on PEM cell performance up to very high current densities of about 5 A/cm². The mass transport effects are discussed in terms of the operating conditions, design parameters and the microstructure of the PTL. The results show that, the operating temperature and pressure, and the inlet water flowrate and thickness of the PTL are the critical parameters for mitigating mass transport limitation at high current densities. The model presented here can serve as a tool for further development and scale-up effort in the area of PEM water electrolysis, and provide insight during the design stage.     

A tree-structured crash surrogate measure for freeways

In this paper, we propose a novel methodology to define and estimate a surrogate measure. By imposing a hypothetical disturbance to the leading vehicle, the following vehicle’s action is represented as a probabilistic causal model. After that, a tree is built to describe the eight possible conflict types under the model. The surrogate measure, named Aggregated Crash Index (ACI), is thus proposed to measure the crash risk. This index reflects the accommodability of freeway traffic state to a traffic disturbance. We further apply this measure to evaluate the crash risks in a freeway section of Pacific Motorway, Australia. The results show that the proposed indicator outperforms the three traditional crash surrogate measures (i.e., Time to Collision, Proportion of Stopping Distance, and Crash Potential Index) in representing rear-end crash risks. The applications of this measure are also discussed.     

核电厂堆芯物理试验功率亏损和功率系数项目的探讨

核电厂首次临界和后续燃料循环都需要进行一系列的试验,其中包括堆芯物理试验,目的是验证堆芯设计计算的正确性。国内压水堆核电厂物理试验由于堆型差异,存在多种堆芯物理试验管理文件。目前,国家核安全局（NNSA）的审评参照法国体系,将堆芯物理试验的文件（堆芯物理试验监督要求GORX）作为最终安全分析报告（FSAR）技术规格书的...     

Optimisation of immobilisation conditions for chick pea β-galactosidase (CpGAL) to alkylamine glass using response surface methodology and its applications in lactose hydrolysis

Response surface methodology was advantageously used to optimally immobilise a β-galactosidase from chick pea onto alkylamine glass using Box–Behnken experimental design, resulting in an overall 91% immobilisation efficiency. Analysis of variance was performed to determine the adequacy and significance of the quadratic model. Immobilised enzyme showed a shift in the optimum pH; however, optimum temperature remained unaffected. Thermal denaturation kinetics demonstrated significant improvement in thermal stability of the enzyme after immobilisation. Galactose competitively inhibits the enzyme in both soluble and immobilised conditions. Lactose in milk whey was hydrolysed at comparatively higher rate than that of milk. Immobilised enzyme showed excellent reusability with retention of more than 82% enzymatic activity after 15 uses. The immobilised enzyme was found to be fairly stable in both dry and wet conditions for three months with retention of more than 80% residual activity.     

Obituary: Samuel Kavruck (1915–2009).

Presents an obituary for Samuel Kavruck, a retired division chief of the U.S. Office of Education and professor emeritus of George Washington University, died of respiratory failure in Rockville, Maryland, on February 24, 2009. After serving in the military as a private during World War II, Kavruck worked with the Veterans Administration and later with the Civil Service Commission as a specialist in test research and development, and he continued with his specialty when he moved to the U.S. Office of Education (1959). Kavruck became a professor of education at George Washington University in 1975, specializing in educational and psychological measurement and research. He also became editor of the Washington Counseletter, a newsletter for educators. He retired in 1984 with emeritus status from George Washington University but continued his work with the newsletter into his final years. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

应用模型拼接建立的全电网模型

为提高电网分析的准确性,调度中心采用的电网模型应从外网等值模型逐步过渡到全电网模型。通过BPA(bonneville power administration)电网模型与能量管理系统电网模型进行模型拼接可生成全电网模型,分析了模型拼接的难点、步骤。算例结果表明应用全电网模型进行电网分析可提高计算精度。     

我国输美食品企业该如何应对美国食品药品监督管理局的趋严检查

近年来,随着我国输美食品的不断增长,美国食品药品监督管理局(Food and Drug Administration,FDA)不断加强对我国输美食品生产企业的检查力度。2016年质检总局(General Administration of Quality Supervision,AQSIQ)对65家出口食品生产企业接受检查案例进行调研,发现随着2011年美国《食品安全现代法》(Food Safety Modernization Act,FSMA)的颁布,美国FDA的检查要求日趋严格,检查范围逐年扩大,对我国输美食品生产企业造成较大影响。本文通过分析美国FDA对我国输美食品生产企业的检查内容,总结该检查对企业造成的主要影响,并提出了相应的应对建议和措施,旨在提醒我国输美食品生产企业沉着应对,依据相关法律法规,制定好"人、机、料、法、环"各个环节的规章制度并严格实施,促使企业顺利通过美国FDA的现场检查,使得对美贸易更加顺畅。