Investigation of titanium liquid/gas diffusion layers in proton exchange membrane electrolyzer cells

In a proton exchange membrane electrolyzer cell (PEMEC), liquid/gas diffusion layer (LGDL) is expected to transport electrons, heat, and reactants/products to and from the catalyst layer with minimum voltage, current, thermal, interfacial, and fluidic losses. In addition, carbon materials, which are typically used in PEM fuel cells (PEMFCs), are unsuitable in PEMECs due to the high ohmic potential and highly oxidative environment of the oxygen electrode. In this study, a set of titanium gas diffusion layers with different thicknesses and porosities are designed and examined coupled with the development of a robust titanium bipolar plate. It has been found that the performance of electrolyzer improves along with a decrease in thickness or porosity of the anode LGDL of titanium woven meshes. The ohmic resistance of anode LGDL and contact resistance between anode LGDL and the anode catalyst play dominant roles in electrolyzer performance, and better performance can be obtained by reducing ohmic resistance. Thin titanium LGDLs with straight-through pores and optimal pore morphologies are recommended for the future developments of low-cost LGDLs with minimum ohmic/transport losses.     

Investigation of the effects of battery types and power management algorithms on drive cycle simulation for a range-extended electric vehicle powertrain

Fuel cell (FC) hybrid vehicle power trains are an attractive technology especially for automotive applications because of their higher efficiency and lower emissions compared to conventional vehicles. This study focuses on the design of an FC hybrid power train system and evaluation of its simulations for a given speed profile through two alternative power management algorithms (PMAs). Parameters suitable for a small vehicle were taken into consideration in the mathematical model of the vehicle. The proposed hybrid power train consists of an energy storage system, composed of a 4-kg battery pack (either lithium-ion (Li-ion) battery, nickel metal hydride, or nickel–cadmium) and a direct methanol fuel cell (DMFC) as the range extender. The PMAs basically aim to fulfill the power requirements of the vehicle and decide how to command the power split between the battery and the FC. The model comprising a DMFC, a battery, and PMAs was developed in MATLAB/Simulink environment. The polarization curve of the FC was obtained using a one-dimensional DMFC model. Vehicle power requirements for a drive cycle were calculated using the equations of longitudinal dynamics of vehicle, and the results were integrated into MATLAB/Simulink model. As a result of the simulations, methanol consumption, state of charge of the battery, and power output of the FC were compared for the PMAs. This comparison shows the effect of PMAs on the hybrid vehicle performance for three battery types. The results indicate that the vehicle range could be increased when proper strategy is used as PMA.     

电化学技术及其在印染废水处理中的应用

电化学技术因其具有高度灵活性、易于控制、污染少等特点倍受研究者的重视。本文主要介绍了电化学技术的各种方法，包括电沉积法、电化学氧化还原法、电吸附法和电渗析法等基本原理。采用上述方法处理染料废水均得到良好效果。同时指出了电化学技术存在电极消耗多、电流效率低等问题；在开发新型电极材料和电化学反应器等方面有待研究。     

Effect of air supply on the performance of an active direct methanol fuel cell (DMFC) fed with neat methanol

Unlike the situation in the direct methanol fuel cell (DMFC) fed with dilute liquid methanol solution, the required water in anode for a DMFC fed with neat methanol is entirely transported from cathode. In this study, the water concentration in anode catalyst layer of such a DMFC operating with fully active mode is theoretically analyzed, followed by the experimental investigations on the effects of air flow rate and operating temperature on cell performance. The results revealed that the air flow rate has a strong impact on cell performance, especially at larger current density. Overmuch air causes rapid decline of cell performance, which results from the dehydration of membrane and lack of water in the anode reaction sites. Raising temperature induces faster reaction kinetics, while undesired stronger water dissipation from the DMFC. In practice, the stable cell resistance can be used as a criterion to help the DMFC to achieve a high and sustainable performance by finely combining the air flow rate and operating temperature.     

“双碳”背景下长三角地区大气污染治理绩效审计评价

本文基于“压力—状态—响应”模型的视角,结合长三角地区客观条件构建了大气污染防治绩效评价审计指标体系。并采用极值熵权法对上述各类指标赋权,结合环境优值模型对长三角地区2016—2020年大气污染治理的效果进行了综合审计评价。研究结果表明,2016—2020年长三角地区平均环境优值整体下降了0.0178,下降幅度达27.16%,大气污染治理绩效具有明显提升趋势;上海市大气环境改善效果最佳,环境优值下降幅度为49.5%;各省（区、市）完成了《打赢蓝天保卫战三年行动计划》的废气污染物减排目标,针对影响大气环境的主要指标推出的各项监管政策得到了有效落实。     

Determination of effects of turbulence flow in a cathode environment on electricity generation using a tidal mud-based cylindrical-type sediment microbial fuel cell

We examined the possibility of harvesting electricity from the surface of a tidal mud flat using a cylindrical-type sediment microbial fuel cell (SMFC), a marine mud battery (MMB), which can be applied in a sea environment where the ebb and flow occur due to tidal difference. In addition, we indirectly investigated the influence of ebb and flow in a lab, using aeration, argon gassing, and by agitating the cathodic solution. The MMBs consisted of cylindrical acrylic compartments containing a nylon membrane, an anode, and a cathode in a single body. The MMBs were stuck vertically into an artificial tidal mud flat such that the anode electrode was in direct contact with the tidal mud surface. As a result, the maximum current and power density generated were 35 mA/m² and 9 mW/m², respectively, thus verifying that it is possible to harvest electricity from the surface of a tidal mud flat using an MMB without burying the anode electrode in the tidal mud. Furthermore, the results of tests using an artificial turbulence flow showed the flow induced by the tidal ebb and flow could allow the performance of MMBs to be enhanced.     

雾化介质阻挡放电联合电晕放电对染料溶液脱色研究

实验将介质阻挡放电与电晕放电组合在一个反应器内,以靛蓝二磺酸钠溶液为实验废水,将高压电极上通入50Hz交流高压电,在常压空气中形成介质阻挡放电-电晕放电系统,放电产生的低温等离子体及其活性基团作用于染料分子。考察了电源电压、电极间距、处理时间对染料溶液脱色率和能量效率水平的影响,确定反应器工作状态为介质阻挡放电系统电极间距30mm、电晕放电系统电极间距25mm、电源电压20kV。     

Experimental Study on the Influence of Rotational Speed on the Performance of a Single-screw Expander with a 175 mm Screw Diameter

A single-screw expander has been designed and manufactured independently. Based on this prototype, testing system has been built and performance experiment has been made. In this article, compressed air was used as working fluid and performance test for the prototype was finished at conditions including different rotational speed and different inlet pressure.

From the experimental data, it is shown that when inlet pressure less than 0.8MPa the output power increases with the increase of rotational speed because of not enough expansion; when inlet pressure more than 0.8MPa, the every biggest output power is appeared in the condition of rotational speed 2600 rpm. The test results also show that the total efficiency is influenced by rotational speed obviously, and the highest total efficiency of this machine is 69.64% in the condition of 3000 rpm and 15 bar.     

Research on distribution performance of desert sand for heat storage in downcomer

In this research, desert sand is used as the sensible heat storage medium, which exchanges heat with air in the downcomer to realize heat storage and heat release. The desert sand distribution uniformity has a significant impact on the heat exchange performance and efficiency between desert sand and air for the process of convection in the downcomer. Given the superiority of sensible heat storage in convective heat transfer between desert sand and air, distributors with cylinder or conical bore solid particles and homogeneity performance testing device are designed and manufactured on the basis of convection system equipped with solid particle–air downcomer. Then, the convection experiment between solid sand and air is researched. The greater the desert sand flow rate and higher the volume density, the larger the variance of regional mass flow rate and the worse the homogeneity performance. For the cylinder bore distributor, the smaller the sand particle size is, the greater affected the sand groups can be. The sand homogeneity performance is preferable with the two particle size ranges: 0.18-0.25 mm and 0.15-0.18 mm. The total sand flow rate decreases, but the uniformity improves with the increase of the air flow velocity, and the best distribution performance is achieved at an air velocity of 0.6 m/s. However, the distribution performance declines with the air flow velocity persistently increasing because the sand groups are pushed to one pipe side close to the wall. The sand groups deflect seriously with the air flow velocity increasing.     

海外油气业务HSSE绩效考核体系建设与实践

为提升HSSE(健康、安全、安保、环境)绩效管理水平,中国石油海外勘探开发公司在海外油气业务建设并推进HSSE绩效考核体系。结合海外实际情况,配套制定一系列制度,并就四类指标进行考核,即杜绝性指标、控制性指标、管理性指标和过程性指标。经过与国际油气生产商(OGP)就亿工时死亡率、损工伤害率、总可记录伤害率对标比较,中国石油海外油气业务HSSE绩效达到国际同行先进水平。海外油气业务推行HSSE绩效考核体系能够有效维持安全环保及社会安全业绩稳定,能够有效保障海外油气项目平稳安全运行。     

基于深度学习的大数据空气污染预报

为了更好地反映环境污染变化趋势,为环境管理决策提供及时、全面的环境质量信息,预防严重污染事件发生,开展城市空气质量预报研究是十分必要的.本文针对环境大数据时代下的城市空气质量预报,提出了一种基于深度学习的新方法.该方法通过模拟人类大脑的神经连接结构,将数据在原空间的特征表示转换到具有语义特征的新特征空间,自动地学习得到层次化的特征表示,从而提高预报性能.得益于这种方式,新方法与传统方法相比,不仅可以利用空气质量监测、气象监测及预报等环境大数据,充分考虑污染物的时空变化、空间分布,得到语义性的污染物变化规律,还可以基于其他空气污染预测方法的结果(如数值预报模式),自动分析其适用范围、优势劣势.因此,新方法通过模拟人脑思考过程实现更充分的大数据集成,一定程度上克服了现有方法的缺陷,应用上更加具有灵活性和可操作性.最后,通过实验证明新方法可以提高空气污染预报性能.     

The right to a healthy environment

Summary The right to have clean water, pure air and wholesome food is as fundamental as the proclamations of The World Charter on Human Rights and The World Charter for Nature. Governments have an obligation to invest in the health and quality of life instead of giving subsidies to polluters. Environmental justice is a level of civilization that we will attain through respect for life and through public information.Mr Yvon Dubé is a forest engineer by training and Assistant Director General, Department of Recreation, Fish and Game, for the Province of Quebec, Canada. He is a member of the Canadian, UNESCO Man and the Biosphere (MAB) Programme Committee. The paper was first presented as a plenary session address to the 1985 Annual Conference of the North American Association for Environmental Education, at Chevy Chase, Maryland, Washington, DC, USA (27 September to 2 October, 1985). The paper has been translated from the original French.     

Optimizing Li2O-2B2O3 coating layer on LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material for high-performance lithium-ion batteries

ABSTRACT

In this paper, a wet chemical method is used to coat LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathode material by Li₂O-2B₂O₃ (LBO) layer for Lithium-ion batteries (LIBs). For performance optimization, the effects of different contents (thicknesses) of LBO coating layers on NCM811 particle surface on the morphologies, structures, compositions, and electrochemical properties of the corresponding LIBs are studied using XRD, SEM, TEM, and electrochemical measurements. Coin LIBs are assembled with such coated NCM811 cathode materials for performance validation. Results show that LBO coating layer does not change the original lattice structure of the bulk material, it can only adhere to the surface of the bulk material. After coating, NCM811 shows a good crystallinity and the ordered layered structure. TEM images show that the thickness of LBO coating is increased with increasing LBO content, and that the appropriate LBO coating thickness and uniform coating state are conducive to the improvement of the electrochemical properties of NCM811 cathode materials. Particularly, NCM811 with LBO coating content of 1000 ppm shows the best performance compared to other coating contents. In this case, the coating thickness is relatively uniform, which is about 40～100 nm, giving a good first charge-discharge capacity of 214.1mAh/g, and a high Coulomb efficiency of 90.06%. After 50 cycles, the capacity retention rate of LIBs still keeps as high as 99.64%. Therefore, LBO coating can improve the performance of NCM811 and then the lithium-ion batteries.     

Comparison study and parameter identification of three battery models for an off-grid photovoltaic system

There is growing interest in solar batteries, especially for photovoltaic (PV) applications. Therefore, an accurate battery model is required for the PV system because of its influence on system efficiency. Several mathematical models of batteries have been described in the scientific literature. However, this paper reviews three electrochemical models most commonly used for PV systems, such as Shepherd, Manegon and Coppetti, in order to define the most appropriate model for PV systems. This paper discusses an application of the pattern search optimization technique to extract the parameters of three battery models derived from experimental test results obtained from sealed gelled lead acid batteries for both charge and discharge modes. A comparative case and regression analysis based on statistical tests and a quantitative method were conducted to demonstrate the effectiveness and accuracy of the updated model from the three aforementioned. The simulation results and tests performed on the battery charge and discharge modes lead us as well to approve the algorithm’s accuracy regarding the updated model.     

燃料电池法去除空气中的CO2

：以Ｐｔ／Ｃ作电极，石棉作电池隔膜，组装成去除ＣＯ２用电池，试验了各种工作条件对电池性能的影响。实验结果证明了电化学方法去除空气中ＣＯ２的可行性。     

Non-linear autoregressive neural network approach for inside air temperature prediction of a pillar cooler

The volcanic plate made pillar cooler system is designed for outdoor spaces as a heat exchanging medium and reduces the outcoming air temperature which flows through the exhaust port. This paper proposes the use of artificial neural networks (ANNs) to predict inside air temperature of a pillar cooler. For this purpose, at first, three statistically significant factors (outside temperature, airing and watering) influencing the inside air temperature of the pillar cooler are identified as input parameters for predicting the output (inside air temperature) and then an ANN was employed to predict the output. In addition, 70%, 15% and 15% data was chosen from a previously obtained data set during the field trial of the pillar cooler for training, testing and validation, respectively, and then an ANN was employed to predict inside air temperature. The training (0.99918), testing (0.99799) and validation errors (0.99432) obtained from the model indicate that the artificial neural network model (NARX) may be used to predict inside air temperature of pillar cooler. This study reveals that, an ANN approach can be used successfully for predicting the performance of pillar cooler.     

三维电极法处理废水的研究进展

传统二维电极面体比小、电流效率低、能耗高等不足而制约了其降解废水的实际应用。三维电极相对于二维电极来说,具有面体比大、离子间距小、传质效果好等优势,因而在降解废水中得到了广泛应用。本文介绍了三维电极的分类、制备方法和载体种类,并对三维电极电催化废水的研究进行了简单的综述。阐述了三维电极在处理废水中的电化学催化机理,同时对三维电极所面临的急需解决的问题和发展趋势作了简要的分析。     

Diversity in sub-national EU implementation: the application of the EU Ambient Air Quality directive in 13 municipalities in the Netherlands

This paper offers an analysis of the implementation performance of the EU Ambient Air Quality directive in the Netherlands. It provides a systematic evaluation of the implementation of a procedural provision – the obligation to design air quality policy. It draws on original data on air quality policy measures that have been collected in 13 medium-sized Dutch municipalities. The analysis of differences in the implementation performance was performed using a novel three-dimensional conceptual framework. The findings illustrate great differences in the implementation performance between the municipalities. The focused comparison allowed establishing very precisely where the implementation performance is poor or even lacking, and which municipalities take their EU implementation task more seriously than others. Most puzzling, environmental problem pressure turned out not to act as a sufficient trigger for municipalities to take far-reaching air quality measures. In contrast to previous research, a more nuanced picture is painted when it comes to the concepts of ‘compliance’, ‘non-compliance’ and ‘over-compliance’. A careful dissection of the implementation performance based on the aspects of the conceptual framework produces hands-on recommendations to municipalities seeking to improve their air quality policy.     

Optimal Design Methods for Hybrid Renewable Energy Systems

Renewable and hybrid energy systems (HESs) are expanding due to environmental concerns of climate change, air pollution, and depleting fossil fuels. Moreover, HESs can be cost effective in comparison with conventional power plants. This article reviews current methods for designing optimal HESs. The survey shows these systems are often developed on a medium scale in remote areas and stand-alone, but there is a global growing interest for larger scale deployments that are grid connected. Examples of HESs are PV–wind–battery and PV–diesel–battery. PV and wind energy sources are the most widely adopted. Diesel and batteries are often used but hydrogen is increasing as a clean energy carrier. The design of an efficient HES is challenging because HES models are nonlinear, non-convex, and composed of mixed-type variables that cannot be solved by traditional optimization methods. Alternatively, two types of approaches are typically used for designing optimal HESs: simulation-based optimization and metaheuristic optimization methods. Simulation-based optimization methods are limited in view of human intervention that makes them tedious, time consuming, and error prone. Metaheuristics are more efficient because they can handle automatically a range of complexities. In particular, multi-objective optimization (MOO) metaheuristics are the most appropriate for optimal HES because HES models involve multiple objectives at the same time such as cost, performance, supply/demand management, grid limitations, and so forth. This article shows that the energy research community has not fully utilized state-of-the-art MOO metaheuristics. More recent MOO metaheuristics could be used such as robust optimization and interactive optimization.     

矿山地质环境保护与治理恢复方案编制中几个技术问题的探讨

以国土资源部颁布的《矿山地质环境保护规定》、《矿山环境保护与综合治理编制规范》和《地质灾害危险性评估技术要求》为原则,结合工作实践,尝试对矿山地质环境评估要求进行了强调与细化,对评估范围的确定方法,对现状评估、预测评估及综合评估的关系、方案适用年限、成果图件的编制等几个矿山地质环境保护与治理恢复方案中的主要技术问题做了初步探讨。