环境样品有机物分析预处理技术研究进展

在环境污染治理过程中,对环境样品进行预处理以进行分析检测必不可少,尤其针对环境中痕量存在的污染物,需经过预处理,浓缩被测痕量组分,以便提高检测方法的灵敏度,降低最小检测极限,并且可以使样品变得容易保存和运输。文章详细介绍了环境样品中有机物分析的预处理方法,将方法分为传统预处理方法和较新预处理方法,传统预处理方法包括:索氏提取法、超声波提取法、真空升华法、气相色谱法、液相色谱法;较新预处理方法包括:超临界流体萃取技术、固相微量萃取技术和吹扫捕集法。分别就传统和较新预处理方法的原理、优缺点及适用范围进行归纳总结和对比,并以多环芳烃的提取为例列举了各方法的应用步骤,从而为其他环境样品其他有机物分析预处理提供参考。     

废弃钻井液固化处理pH值控制措施

提出了在原有固化处理技术的基础上,根据钻井泥浆原样pH值的高低,在固化材中适量加入酸性盐类混凝剂有效控制pH值的方法。采用此方法后,废弃钻井液的固化处理效果好,能够满足环保标准要求。     

基于形态滤波遗传算法对目标红外图像特征检测

将形态滤波和自适应遗传算法结合起来,提出了一个用于目标检测的形态滤波器参数优化遗传算法。通过设计了形态滤波的遗传算法,寻求最佳结构元,以实现对目标的自适应检测。作为2个特殊环境中的应用检测实例,分别对固体推进器尾喷焰红外图像和复杂背景下的弱小目标进行检测。实验结果表明该方法能够更好地适应环境变化,更大程度地提高目标信号检测的信号噪声（SNR）比,有效地检测出复杂背景下的目标。     

Review of hydrogen safety during storage,transmission, and applications processes

Hydrogen is considered an excellent clean fuel with potential applications in several fields. There are serious safety concerns associated with the hydrogen process. These concerns need to be thoroughly understood and addressed to ensure its safe operation. To better understand the safety challenges of hydrogen use, application, and process, it is essential to undertake a detailed risk analysis. This can be achieved by performing detailed consequence modellings and assessing risk using the computational fluid dynamics (CFD) approach. This study comprehensively reviews and analyses safety challenges related to hydrogen, focusing on hydrogen storage, transmission, and application processes. Range of release and dispersion scenarios are investigated to analyse associated hazards. Approaches to quantitative risk assessment are also briefly discussed.     

多源数据支持下城市火灾风险评估及规划响应

为探析城市火灾风险的空间格局特征,提出科学的火灾防控体系,以合肥市为研究对象,基于火灾风险兴趣点(POI)数据、NPP/VIIRS夜间灯光影像数据、消防站与道路信息等多源数据,运用SAVEE模型和迭代方程评估城市火灾风险,并引入区位-配置(L-A)模型,从不同目标情境优化消防站点布局。研究表明:火灾高风险区主要集中于合肥市二环以内的建成区,尤其是老城区、合肥西站片区、政务区、科学城和东部新中心等区域;现有48座消防站对研究区内的POI覆盖效果较好,覆盖率为86.76%,而对NPP/VIIRS覆盖效果一般,覆盖率仅为55.94%,覆盖率在合肥市东北部、西北部和南部部分地区仍有不足;基于最大化覆盖模型,规划新增44座消防站,明显提升5 min响应时间的覆盖率,可进一步夯实城市消防安全。     

Green energy generation through PEHF – a blueprint of alternate energy harvesting

In this work, an attempt has been made to harvest green energy from piezoelectric material using fluid flow in a conduit. Piezoelectric Energy Harvesting using Fluid Flow (PEHF) experimental model has been designed and the outputs obtained are compared with results obtained from simulations using ANSYS (computational fluid dynamics) and also with the mathematical modeling. The PEHF model has been utilized to analyze the effect of flow rate of water with reference to energy extracted. The full wave bridge rectifier and voltage doubler circuits have been used to obtain the direct current (DC) from the PEHF model. It is observed that the output obtained using experiments holds good in agreement with the results retrieved through simulations and mathematical results. The increase in flow rate of fluid leads to initially increase and then decrease in output of PEHF model as the maximum energy generated when flow rates (external force) matches with the frequency of excitation of the systems, i.e., at its resonance. The maximum energy output is generated at its resonance frequencies. It is observed that the full wave bridge rectifier circuit gives greater output as compared to a voltage doubler circuit.     

Dynamic contact angle effects on gas-liquid behaviors in the cathode of proton exchange membrane fuel cell with stirred tank reactor design

Liquid water management is still a critical issue in the improvement of proton exchange membrane fuel cell (PEMFC) performance. In this work, for the first time, the liquid water behavior and transport inside the cathode of a PEMFC with a stirred tank reactor (STR) design, rather than the conventional PEMFC flow channel design, are numerically studied. The dynamic contact angle (DCA) is applied to multiple wall boundaries in the numerical model through a user-defined-function (UDF) code, i.e., STR-DCA model. Another numerical model with the static contact angle (SCA) and same operating conditions, i.e., STR-SCA model, is also developed for comparison. The volume of fluid (VOF) method is employed in the simulation to track the gas-liquid interface. The results show that the liquid water distribution and transport are significantly different between these two models, indicating the remarkable effects of DCA on the simulation results. It is also verified the capability of STR-PEMFC to reduce the liquid water flooding, showing the potential of this channel-less type fuel cell in the further development.     

Assumptions beyond the science: encouraging cautious conclusions about functional magnetic resonance imaging research on organizational behavior

Functional magnetic resonance imaging (fMRI) is likely to become the major tool for studying the neural underpinnings of organizational behavior. It is a technique for brain imaging that, according to advocates, provides information about which areas of the brain are activated during organizational processes (e.g., leadership and decision‐making). In this article, we take a critical look at this tool from a technical perspective. In particular, we take the reader through the assumptions that must be made at the three main steps of the research process (study design, data capture, and interpretation of results) in order to draw conclusions about organizational phenomena from fMRI research. Applying this analysis to three case studies demonstrates the gap between what fMRI can actually tell us and the claims often made about the contribution of fMRI to understanding and improving organizational behavior. Our discussion provides researchers with a series of recommendations oriented toward optimizing the use of fMRI to help it live up to its potential in the field of organizational behavior and consumers with a means of evaluating fMRI research in order to draw appropriate and warranted conclusions. Copyright © 2016 John Wiley & Sons, Ltd.     

Estimating emissions from crop residue open burning in China based on statistics and MODIS fire products

With the objective of reducing the large uncertainties in the estimations of emissions from crop residue open burning, an improved method for establishing emission inventories of crop residue open burning at a high spatial resolution of 0.25°× 0.25° and a temporal resolution of1 month was established based on the moderate resolution imaging spectroradiometer(MODIS) Thermal Anomalies/Fire Daily Level3 Global Product(MOD/MYD14A1). Agriculture mechanization ratios and regional crop-specific grain-to-straw ratios were introduced to improve the accuracy of related activity data. Locally observed emission factors were used to calculate the primary pollutant emissions. MODIS satellite data were modified by combining them with county-level agricultural statistical data, which reduced the influence of missing fire counts caused by their small size and cloud cover. The annual emissions of CO_2, CO, CH_4,nonmethane volatile organic compounds(NMVOCs), N_2O, NO_x, NH_3, SO_2, fine particles(PM2.5),organic carbon(OC), and black carbon(BC) were 150.40, 6.70, 0.51, 0.88, 0.01, 0.13, 0.07, 0.43,1.09, 0.34, and 0.06 Tg, respectively, in 2012. Crop residue open burning emissions displayed typical seasonal and spatial variation. The highest emission regions were the Yellow-Huai River and Yangtse-Huai River areas, and the monthly emissions were highest in June(37%).Uncertainties in the emission estimates, measured as 95% confidence intervals, range from a low of within ±126% for N_2O to a high of within ± 169% for NH_3.     

生物酶破胶水基压裂液影响因素的试验研究

与其他压裂液破胶剂相比,生物酶破胶剂能很好地保护环境,而影响生物酶破胶水基压裂液效果的因素主要是底物的浓度、酶的加量、pH值以及破胶温度.本文采用正交试验设计,分析了各因素对生物酶破胶水基压裂液效果的影响程度,并分析了各因素不同水平对压裂液黏度的影响趋势,结果表明调整各因素的不同水平可以实现不同的压裂液黏度和破胶时间,...