深圳抽水蓄能电厂球阀动水关闭试验研究

为验证深圳抽水蓄能电厂球阀具备动水关闭能力且不会产生有害振动进行了球阀动水关闭试验,获得不同负荷下球阀动水关闭实测各项动应力值及振动位移值。试验数据表明深蓄电厂球阀在不关闭导叶情况下能可靠关闭阻断上游来水,验证了在100%负荷动水关闭球阀最不利工况下,球阀混凝土支墩结构强度满足设计要求,球阀体系的振动位移是安全的,且对设备未产生有害变形及损坏。     

Pittsburgh's translocal social movement: A case of the new public water

This paper contributes to the water privatization and governance literatures by examining the case of Pittsburgh where renewed efforts of water privatization have emerged after a failed private management arrangement between the local water authority and Veolia ended abruptly in 2015. We argue that, as the water authority aims to rebuild trust in the community, resident mobilization has played a key role in hindering further privatizing arrangements and has exerted influence in defining what constitutes the “new public” water in Pittsburgh, by advocating for increased transparency and accountability in governance, infrastructure improvements and protections for low-income residents.     

A fuel cell powered autonomous surface vehicle: The Eco-SWAMP project

Autonomous surface vehicles are becoming consolidated robotic tools for marine, coastal and inland surveys. Autonomous surface vehicles are usually equipped with electronic instruments to perform remotely controlled or autonomous geo-morphological, biological, chemical, physical analyses and data collection. Actually, well-established solutions provide battery power but the research focuses on introducing a fuel cell to decrease the environmental impact meanwhile increasing the cruising range. In this paper, the design of the Eco-SWAMP, a fuel cell powered autonomous surface vehicle, is presented starting from its battery-powered version, the SWAMP prototype. The experimental power consumption profile of the SWAMP during four missions is analysed to define the primary energy sources ratings of the Eco-SWAMP. After a commercial choice of primary sources, power management algorithms are designed and compared in MATLAB/Simulink environment by simulation results. The proposed procedure can be easily applied to any autonomous marine vehicle.     

我国两部制电价制度对天然气发电企业盈利能力的影响

上海、浙江和江苏等地陆续出台了两部制电价制度,以期解决天然气发电(以下简称气电)企业成本高、经营困难等问题。为了研究该电价制度对气电企业盈利能力的影响,在对比分析上述三地电价政策和实施效果的基础上,基于不同类型机组的三大经营指标(项目财务内部收益率、经济净现值、动态投资回收期),采用项目经济性分析模型探究了不同类型燃气电厂的经济性。研究结果表明:①现行两部制电价与单一制电价相比,电价水平小幅度下降,给企业经营带来了一定的冲击,但从长远看,则有利于形成可持续的发展机制;②两部制电价是各地政府经过充分调研和测算后根据该区具体情况制定的,在该政策下多数企业处于盈亏平衡点附近,综合条件优、管理水平高的企业能取得一定的盈利,反之则亏损;③当电量电价一定且大于盈亏平衡点时,企业效益随年利用小时数的增加而提升,反之则随年利用小时数的增加而降低。结论认为:①两部制电价能起到促进企业管理和技术水平提升,引导和鼓励电力投资的作用,符合我国电力体制改革的方向;②政策制定时应针对不同时期建成的项目加以区别对待,实现上网电价、天然气价格和供热蒸气价格的"三个联动";③应建立大数据平台,实行气网、电网联合调度;④发电企业应创新管理,降低电厂建设及维护成本,提升机组效率,降低气耗。     

上海天然气市场和液化天然气的现状与展望

2009年,上海能源供应体系自从引入液化天然气以来,进口液化天然气对全市天然气供应总量和来源多元化做出了重要贡献。2013年,液化天然气消费在全市天然气消费总量中占比达50%,在天然气供应体系中发挥了越来越重要的作用。近年来,上海天然气市场发生了深刻变化,天然气需求增长放缓,与2013年之前十多年的两位数增长形成了鲜明对比。为了更好地理解市场的基本面,首先回顾了上海天然气消费的历史趋势,随后分析了影响需求增长的驱动因素和约束条件,以判断未来天然气需求的趋势和液化天然气在市场中扮演的角色,认为天然气需求增长的潜力主要在民用及商业领域。结合分析可能的供应选择,其结论是未来液化天然气将继续作为上海天然气供应体系的主力气源,同时提供市场急需的灵活性以保障高峰时段的用气需求。     

Multi-stage power source and grid coordination planning method considering grid uniformity

Given the increasing uncertainties in power supply and load, this paper proposes the concept of power source and grid coordination uniformity planning. In this approach, the standard deviation of the transmission line load rate is considered as the uniformity evaluation index for power source and grid planning. A multi-stage and multi-objective optimization model of the power source and grid expansion planning is established to minimize the comprehensive cost of the entire planning cycle. In this study, the improved particle swarm optimization algorithm and genetic algorithm are combined to solve the model, thus improving the efficiency and accuracy of the solution. The analysis of a simple IEEE Garver’s 6-node system shows that the model and solution method are effective and feasible. Moreover, they are suitable for the coordinated planning of the power source and grid under a diversified nature of power supply and load.     

Compiler compatible 5.66 Mb/mm2 8T 1R1W register file in 14 nm FinFET technology

1-read/1-write (1R1W) register file (RF) is a popular memory configuration in modern feature rich SoCs requiring significant amount of embedded memory. A memory compiler is constructed using the 8T RF bitcell spanning a range of instances from 32 b to 72 Kb. An 8T low-leakage bitcell of 0.106 μm² is used in a 14 nm FinFET technology with a 70 nm contacted gate pitch for high-density (HD) two-port (TP) RF memory compiler which achieves 5.66 Mb/mm² array density for a 72 Kb array which is the highest reported density in 14 nm FinFET technology. The density improvement is achieved by using techniques such as leaf-cell optimization (eliminating transistors), better architectural planning, top level connectivity through leaf-cell abutment and minimizing the number of unique leaf-cells. These techniques are fully compatible with memory compiler usage over the required span. Leakage power is minimized by using power-switches without degrading the density mentioned above. Self-induced supply voltage collapse technique is applied for write and a four stack static keeper is used for read Vmin improvement. Fabricated test chips using 14 nm process have demonstrated 2.33 GHz performance at 1.1 V/25 °C operation. Overall V_min of 550 mV is achieved with this design at 25 °C. The inbuilt power-switch improves leakage power by 12x in simulation. Approximately 8% die area of a leading 14 nm SoC in commercialization is occupied by these compiled RF instances.     

Experimental study of the pyrolysis of waste bitumen for oil production

This work focuses on bitumen slow pyrolysis. Mass and energy yields of oil, solid and gas were obtained from pyrolysis experiments using a semi-batch reactor in a nitrogen atmosphere, under three non-isothermal conditions (maximum temperature: 450 °C, 500 °C and 550 °C). The effect of temperature on the product yields was discussed. The gas compositions were analysed using gas chromatography (GC) and the heating value of oil and solid residue was also measured. Using a thermo-gravimetric analyser, kinetic parameters were evaluated through Ozawa-Flynn-Wall (OFW) method. Results showed that oil yield is maximum at 500 °C (50%). Moreover, gas yield increased with increasing pyrolysis temperature from 18% to 36%. On the other hand, solid yield showed an opposite trend: it decreased from 39% to 32%. As regard energy yields, they showed a similar trend with the mass ones. H_2, CH₄, C₂H₄, C₂H₆ and C₃H₈ are the main components of the produced gas phase. It has been noticed that the recovery of bitumen to liquid oil through pyrolysis process had a great potential since the oil produced had high calorific value comparable with commercial fuels.     

Improving hydrogen evolution reaction and capacitive properties on CoS/MoS2 decorated carbon fibers

We report a facile method to transform abundantly dumped banana stem fibers into carbon fibers (CFs) useful for energy applications. The CFs surface area is increased by varying the quantity of KOH activation to 488 m²g^-1. The solvothermal method is used to synthesize CoS, CoS/MoS₂ and also grown on the activated carbon fibers (ACFs). Nano nodules of CoS arranged into sheets and layers of MoS₂ stacked together were found in FESEM analysis. The morphology of the CoS/MoS₂ differs when grown on ACFs. The growth of CoS/MoS₂ along the ACFs length prevents any stacking of the pseudocapacitance materials. The ternary composite ACFs/CoS/MoS₂ exhibits superior supercapacitor behavior as well as hydrogen evolution reaction (HER) due to the synergetic effect of the conducting ACF surface and redox active CoS/MoS₂. A maximum specific capacitance of 733 Fg^-1, energy and power density of 33 WhKg⁻¹ and 999 WKg^-1 respectively are obtained. A low Tafel slope value of 61 mVdec⁻¹ is obtained for the ACFs/CoS/MoS₂ ternary composite electrode. The present work therefore offers a fresh insight into the effective conversion of waste materials into electrode material for energy storage and conversion applications.