. The effects of che

stimated.damping, Mg-Zr alloys, research中国人民解放军武器装备重点基金项目(6140502)0材料导报Materials Review436-439 450TG132B0222B;B022_2刘广;425-42     

Condensation of Mixed Vapors—Integral vs. Differential

Abstract

The heat and mass transfer processes taking place within a condenser for a mixture of vapors (total or partial condensation) will differ very significantly depending on whether integral or differential condensation is involved. It will be demonstrated that a failure to recognize this difference and thus to select an inappropriate condenser geometry can lead to the catastrophic failure of the unit to perform the anticipated duty.     

Multilayered Plate Model with “Adaptive” Representation of Displacements and Temperature Across the Thickness and Fixed D.O.F.

A new multilayered zig-zag plate model for analysis of thermo-elastic problems is developed. It a priori fulfils the boundary conditions and the stress contact conditions on interlaminar shear and normal stresses and the continuity of the heat flux and temperature at the layer interfaces, as prescribed by the elasticity theory and heat conduction equation. The functional d.o.f. are the mid-plane displacements and shear rotations, like for classical plate models, and the temperature at the upper and lower bounding faces. A non-classical feature, a high-order piecewise variation of the transverse displacement is assumed across the thickness aimed at accurately describing the transverse normal stress, as it has a significant bearing for keeping equilibrium in thermo-elastic problems. Also non classical feature, the representation of displacements and temperature can be different from point to point across the thickness, to adapt to the variation of solutions. This refinement is obtained by keeping the number of functional d.o.f. unchanged, since the coefficients of the hierarchic contributions are determined enforcing the fulfillment of the equilibrium and heat conduction equation at selected points across the thickness. As shown by the comparison with exact solutions of benchmark test cases, the present model accurately predicts displacement, stress and temperature variations across the thickness from constitutive equations, even when thickness is extreme and the thermo-elastic properties of layers are distinctly different. Its basic advantage over existing models is a lower computational effort under the same accuracy.     

Reviews of selected 100 recent papers for lithium batteries （Oct. 1,2014 to Nov. 30,2014）

该文是一篇近两个月的锂电池文献评述,我们以“lithium”和“batter*”为关键词检索了Web of Science从2014年10月1日至2014年11月30日上线的锂电池研究论文,共有971篇,选择其中100篇加以评论。层状氧化物正极材料主要研究了NCA的热稳定性及表面包覆对材料循环寿命的影响,高电压的尖晶石结构LiNi_0.5M_1.5O₄材料主要研究了掺杂和表面包覆的作用。高容量的硅、锡基负极材料研究侧重于纳米材料、复合材料、黏结剂及电极制备和反应机理研究,电解液添加剂、固态电解质、锂空电池、锂硫电池的论文也有多篇。理论模拟工作包括SEI研究、材料中的锂扩散和材料与电池安全性关系的分析,除了这些以材料为主的研究之外,针对电池的原位分析、电池模型、电极制造技术的研究论文也有多篇。     

Reviews of selected 100 recent papers for lithium batteries （Dec. 1,2014 to Jan. 31,2015）

该文是一篇近两个月的锂电池文献评述,我们以“lithium”和“batter*”为关键词检索了Web of Science从2014年12月1日至2015年1月31日上线的锂电池研究论文,共1890篇,选择其中100篇加以评论。正极材料主要研究了富锂相材料的结构演变及表面包覆对层状和尖晶石材料循环寿命的影响。高容量的硅、锡基负极材料研究侧重于纳米材料、复合材料、黏结剂及反应机理研究,电解液添加剂、固态电解质、锂空电池、锂硫电池的论文也有多篇。理论模拟工作包括材料体相、界面结构和输运性质,除了以材料为主的研究之外,针对电池的原位分析、电池模型的研究论文也有多篇。     

Impact of H.I. Schlesinger's discoveries upon the course of modern chemistry on B−(N−)H hydrogen carriers

Representatives of B?(N?)H hydrogen carriers are alkali borohydrides (e.g. LiBH₄ and NaBH₄) and amine boranes (e.g. NH₃BH₃ and NaNH₂BH₃). These are old compounds; they were discovered in the first half of the 20th century. One of the main contributors to their development is Prof. Hermann I. Schlesinger (1882–1960). In the recent years, there has been new interest in these old compounds as novel chemical H storage materials. Sodium borohydride NaBH₄ is a typical example. It was discovered by Schlesinger and collaborators in the 1950s. At that time it was found to be an attractive H₂ generator; owing to this property it reemerged in the early 2000s for on-board H₂ generation. Today, Schlesinger is commonly considered as the pioneer of NaBH₄ as hydrogen carrier but the impact of Schlesinger and collaborators' discoveries upon the course of modern chemistry on B?(N?)H hydrogen carriers is far more extensive … This is highlighted herein.     

Reviews of selected 100 recent papers for lithium batteries （Aug. 1,2015 to Sept. 30,2015）

该文是一篇近两个月的锂电池文献评述,我们以“lithium”和“batter*”为关键词检索了Web of Science 从2015年8月1日至2015年9月30日上线的锂电池研究论文,共有2432篇,选择其中100篇加以评论。正极材料主要研究了富锂相材料、三元材料和尖晶石材料的掺杂和表面包覆及界面层改进对其循环寿命的影响。高容量的硅、锡基复合负极材料研究侧重于SEI界面层、复合材料、黏线剂及反应机理研究,电解液添加剂、固态电解质、锂空电池、锂硫电池的论文也有多篇。理论模拟工作包括电极材料体相和界面结构以及电解质的输运性质,除了以材料为主的研究之外,针对电池的状态估计、失效分析、热安全分析的研究论文也有多篇。     

Decarbonization of the U.S. electricity sector: Are state energy policy portfolios the solution?

State governments have taken the lead on U.S. energy and climate policy. It is not yet clear, however, whether state energy policy portfolios can generate results in a similar magnitude or manner to their presumed carbon mitigation potential. This article seeks to address this lack of policy evidence and contribute empirical insights on the carbon mitigation effects of state energy portfolios within the U.S. electricity sector. Using a dynamic, long-term electricity dispatch model with U.S. power plant, utility, and transmission and distribution data between 2010 and 2030, this analysis builds a series of state-level policy portfolio scenarios and performs a comparative scenario analysis. Results reveal that state policy portfolios have modest to minimal carbon mitigation effects in the long run if surrounding states do not adopt similar portfolios as well. The difference in decarbonization potential between isolated state policies and larger, more coordinated policy efforts is due in large part to carbon leakage, which is the export of carbon intensive fossil fuel-based electricity across state lines. Results also confirm that a carbon price of $50/metric ton CO₂e can generate substantial carbon savings. Although both policy options – an energy policy portfolio or a carbon price – are effective at reducing carbon emissions in the present analysis, neither is as effective alone as when the two strategies are combined.     

How do oil price shocks affect the output volatility of the U.S. energy mining industry? The roles of structural oil price shocks

This paper focuses on how explicit structural shocks that characterize the endogenous character of international oil price change affect the output volatility of the U.S. crude oil and natural gas mining industries. To this end, we employ a modified structural vector autoregressive model (SVAR) to decompose real oil-price changes into four components: U.S. supply shocks, non-U.S. supply shocks, aggregate demand shocks, and oil-specific demand shocks mainly driven by precautionary demand. The results indicate that output volatility of the U.S. crude oil and natural gas mining industry has significantly negative responses to U.S. supply shocks, aggregate demand shocks, and oil-specific demand shocks, while lacks significant response to non-U.S. supply shocks. Variance decomposition and historical decomposition confirm that U.S. supply shocks occupy most explaining variations in output volatility among the four structural oil shocks. Moreover, the oil-specific demand shocks explain more variation than that of aggregate demand shocks for the crude oil mining industry, but the opposite is true for the natural gas mining industry.     

Co-liquefaction of Yatağan lignite and waste tire under catalytic conditions. Part 1. Effect of fresh tetraline and recycled tetraline on the conversion

In this study, the effect of solvent type and the solvent/solid ratio on the liquefaction of Mu?la-Yatagan lignite (YL) combined with waste tire (WT) under catalytic conditions investigated. Liquefaction experiments carried out the following conditions, a reaction temperature of 400°C, a catalyst concentration of 3%, solvent/solid ratio from 1/1 to 9/1, reaction time of 90 min, lignite/waste ratio of 1/1. In addition, mixing speed was 400 rpm, and the nitrogen gas pressure fixed at 30 bar. After the each of liquefaction experiments finished, the soluble products (SP) classified as preasphaltene (PAS), asphaltene (AS) and oil+gas (OG), by solvent extraction. Due to the optimum total conversion determined, fresh tetraline obtained as the most favorable solvent with 71.71%, for the liquefaction of YL with WT. However, the total conversion for recycling tetraline is 68.6%. According to the results, co-liquefaction of YL combined with WT using recycle solvent is the one way to offer, alternatively of using crude oil, producing SP for not crude oil, producing SP for not only fuel-oil production but also prefer chemical raw materials. With respect to the optimum oil+gas yield results, the most convenient solvent type and the solvent/solid ratio are the recycled solvent and its 3/1 ratio.     

Counter-current hydrogen–oxygen vortex combustion chamber. Thermal physics of processing

The expediency is substantiated for the use of a vortex counter-current circulation flow of water steam and the stoichiometric hydrogen-oxygen mixture as a source of heat generation. That flow is essential for the purpose of making efficient models of high-temperature combustion chambers for the cogeneration cycles.An experimental investigation was carried out of hydrogen-oxygen mixture combustion in a counter-current combustion chamber-superheater. Operating range values of heat power were obtained. A maximum temperature of the superheated steam at the combustion chamber outlet was 1350 K. There were determined the optimal modes of hydrogen-oxygen mixture outflow ensuring its steady combustion in the counter-current flow core of the water steam.     

Direct solar thermal splitting of water and on-site separation of the products—II. Experimental feasibility study

The development of a process of hydrogen production by solar thermal water splitting (HSTWS) presents a formidable technological task. The process has, however, great potential from the thermodynamic point of view and, when combined with fuel cell technology, it can lead to efficient conversion of solar energy to power. In the process under development at the Weizmann Institute of Science, water vapor is partially dissociated in a solar reactor at temperatures approaching 2500 K. Hydrogen is separated from the hot mixture of water splitting products by gas diffusion through a porous ceramic membrane.The paper describes the problems encountered during the development of the HSTWS process. The following topics are discussed in some detail: (a) achievement of very high solar hydrogen reactor temperatures by secondary concentration of solar energy; (b) materials problems encountered in the manufacture of the solar reactor; (c) development of special porous ceramic membranes that resist clogging by sintering at very high temperatures.     

Red Eléctrica de España S.A.: Instrument of regulation and liberalization of the Spanish electricity market (1944–2004)

To understand the regulation system of the Spanish electricity market it is first necessary to understand on the one hand the system of tariffs and prices, and on the other the organization of the market for high voltage distribution. This article is concerned with this second aspect and traces its history from 1944, this is because before that date it was not possible to speak of a truly national market, but rather only of regional monopolies. In the 1940s, with Franco's new political regime, and the development of the Spanish electricity sector, it became necessary to completely rethink business strategies in relation to competition and cooperation, as well as the regulatory function of the state. In the 1950s, the main feature of the sector was the system of business self-regulation permitted by the state. Throughout the remaining years of Franco's government state intervention was particularly focussed on the subject of tariffs, but with the onset of democracy the state was to involve itself in the transmission network as well. A debate began as to whether it should be run by a private or public operator. In this dispute were ranged, on the one hand, the economic policy concepts of the major parties (PSOE and PP), and against them the strategic interests of the companies. Although the high voltage transmission network was nationalized by the state in the mid-1980s, establishing a ‘traditional’ model of regulation, the 1990s saw the triumph of a market-based regulation, strongly influenced by the dominant ideas in the European Union, which has converted Red Eléctrica into a private company. Currently the TSO (Transmission System Operators) model has been extended to Portugal and has entered into competition–cooperation with the other models of the European electricity market.