Synergy of elemental Fe and Ti promoting low temperature hydrogen sorption cycling of magnesium

We studied the catalytic effects of Titanium, Iron and FeTi intermetallic on the desorption kinetics of magnesium hydride. In order to separate the catalytic effects of each element from additional synergistic and alloying effects, Mg-Ti and Mg-Fe mixtures were studied as a baseline for Mg-Fe-Ti elemental and Mg-(FeTi) intermetallic composites. Sub-micron dimensions for MgH₂ particles and excellent nanoscale catalyst dispersion was achieved by high-energy ball-milling as confirmed by analytical electron microscopy techniques. The composites containing Fe shows desorption temperature of 170 K lower than as-received MgH₂ powder, which makes it suitable to be cycled at relatively low temperature of 523 K. Furthermore, the low cycling temperature prevents the formation of Mg₂FeH₆. In sorption cycling tests, Mg-10% Ti and Mg-10% (FeTi), after about 5 activation cycles, show fast desorption kinetics initially, but the kinetics also degrade faster than for all other composites, eventually slowing down by a factor of 7 and 4, respectively. The ternary Mg-Fe-Ti composite shows best performance. With the highest BET surface area of 40 m²/g, it also shows much less degradation during cycling. This is attributed to titanium hydride acting as a size control agent preventing agglomeration of particles; while Fe works as a very strong catalyst with uniform and nanoscale dispersion on the surface of MgH₂ particles.     

Introduction to the Asian Energy Security project: Project organization and methodologies

The spectacular recent economic growth in the Asia-Pacific region in general, and in many of the economies of Northeast Asia in particular, has spurred a vast expansion in the need for energy services, and an expansion in the demand for the fuels that help to supply these services. Future projections suggest that the growth of fossil fuel use in Northeast Asia, especially in China, will have major consequences for financial and fuel markets and pollution both regionally and globally. Before the project described in this paper was initiated, there was no ongoing forum for energy experts from all of the countries of the region to meet, informally and in an unofficial capacity, to discuss openly and in a targeted fashion the energy situations in their countries, and to work together to evaluate the energy efficiency costs and benefits of different ways of meeting regional demand. The Asian Energy Security (AES) project provides such a forum, and as such constitutes a unique resource in the engagement of the countries of Northeast Asia on the topic of energy security.     

Energy security and sustainability in Northeast Asia

“Energy Security” has typically, to those involved in making energy policy, meant mostly securing access to oil and other fossil fuels. With increasingly global, diverse energy markets, however, and increasingly transnational problems resulting from energy transformation and use, old energy security rationales are less salient, and other issues, including climate change and other environmental, economic, and international considerations are becoming increasingly important. As a consequence, a more comprehensive operating definition of “Energy Security” is needed, along with a workable framework for analysis of which future energy paths or scenarios are likely to yield greater Energy Security in a broader, more comprehensive sense. Work done as a part of the Nautilus Institute's “Pacific Asia Regional Energy Security” (PARES) project developed a broader definition of Energy Security, and described an analytical framework designed to help to compare the energy security characteristics – both positive and negative – of different quantitative energy paths as developed using software tools such as the LEAP (Long-range Energy Alternatives Planning) system.     

Reliable in the long run? Petroleum policy and long-term oil supplier reliability

Accelerating oil import dependence in energy consuming nations highlights the importance of having energy supplies at sufficient levels and at stable and reasonable prices. Consequently, it is crucial that oil exporters realize their full production potential. Current debates on energy security are often focused on short-term risks e.g. sudden disruptions due to wars, domestic instability, etc. However, when it comes to assessing oil supplier reliability it is equally important to assess their longer term ability and willingness to deliver oil to the global market. This study analyzes the effects of petroleum investment policies on crude oil production trends in 14 major oil producing countries (2000–2010) by focusing on the political–institutional frameworks that shape the investment conditions for the upstream oil sector. Our findings indicate that countries with less favorable oil sector frameworks systematically performed worse than countries with investor friendly and privatized sectors. The findings indicate that assessments based on remaining reserves and planned production capacities alone could inflate expectations about future oil supplies in a world where remaining crude reserves are located in countries with unfavorable investment frameworks.     

Variable temperature neutron diffraction studies of single crystals of LiND2

We have synthesized a single crystal of lithium amide (LiNH₂, LiND₂) by melting method, and performed neutron diffraction of the single crystal at variable temperature. LiND₂ is tetragonal structure and I-4 space group. Lattice parameters and unit cell volume of LiND₂ at room temperature, 50 °C, 100 °C, 150 °C and 200 °C were determined. Both of the lattice parameters and the unit cell volume increase with increase of temperature. From these results, we have estimated coefficient of volumetric thermal expansion α_V of LiND₂ to be 222 × 10⁻⁶/K. With increase of temperature, all thermal ellipsoids gradually expand because of thermal vibration.     

Polychlorinated biphenyl,DDT and dieldrin residues in grey seal (Halichoerus grypus) males,females and mother-foetus pairs sampled at the Farne Islands,England, during the breeding season

PCB, DDT, DDE, dieldrin and total non-polar organohalogen residues have been determined in the blubber-lipid of grey seals (Halichoerus grypus) sampled during the 1972 breeding season (November) at the Farne Islands off the north eastern coast of England. PCBs were analysed by gas-liquid chromatography linked to a chlorine- and carbon-selective microwave plasma detector and total organohalogen residues were determined by microcoulometry.Total organohalogen residues were negatively correlated with blubber thickness and positively correlated with age in males (aged 1 to 24 y) and females (aged 5 to 38 y). However, the correlation of blubber-lipid residue with age in males depended upon the inclusion of immature (aged < 6 y) animals, and in females reflected only a small residue increment. The mean blubber organohalogen concentration of the males was significantly greater than that of the females. PCB and DDT group residue concentrations were significantly correlated.PCB, DDT, DDE and dieldrin were detected in the liver of mother/foetus pairs demonstrating transplacental movement of these residues.The possibility of the condition of the seals at breeding time influencing residue levels and of these residues influencing the health of the population is discussed.     

Long-Wave and Integral Boundary Layer Analysis of Falling Film Flow on Walls With Three-Dimensional Periodic Structures

Falling films exhibit very complex wavy patterns, which depend on the properties of the liquid, the Reynolds number, the wall inclination angle, and the distance from the film inlet. The film hydrodynamics governs the heat and mass transfer in the liquid films. Our vision is to control and enhance heat and mass transport by using walls with specific microscale topographies that influence the falling film flow, stability, and wavy pattern. In this work, long-wave theory and integral boundary layer approximation are used for modeling the falling film flow on walls with three-dimensional periodic microstructures. The wall topography is periodic both in the main flow direction and in the transverse direction. Examples of such microstructures are longitudinal grooves with sinusoidal path (or meandering grooves) and herringbone structures. The effects of the Reynolds number, the wall inclination angle, and the longitudinal and transverse periods of the structure on the shape of liquid–gas interface are investigated. It is shown that, as opposed to straight grooves in longitudinal direction, grooves with meandering paths may lead to significant interface deformations.     

Application of geothermal absorption air-conditioning system: A case study

Possible applications of geothermal energy are increasingly attracting worldwide interest as a low carbon source of energy. Sedimentary basins offer an accessible low grade geothermal heat source to launch energetically efficient air-conditioning systems. The natural temperature, porosity and permeability of these sedimentary basins may be sufficient to provide usable geothermal power for heat-driven sorption air-conditioning system. In the Perth metropolitan region, hot sedimentary aquifers with temperatures between 70 and 100 °C are generally available at around 3 km depth or shallower. This paper outlines the possible application of a large scale geothermal absorption air-conditioning system to provide baseload cooling to the main campus of the University of Western Australia (UWA). The conceptual design of this system is proposed. The design considerations and the performance outcomes are presented. The economic analysis based on the real-time cooling load profile at the UWA and the chiller operation scheme demonstrates the viablity of geothermal absorption air-conditioning system. This paper will help engineers appreciate the opportunities and barriers to geothermal applications, the latest developments and how this technology may help to significantly reduce carbon dioxide emissions.     

口罩认知与SARS防护

本文介绍了口罩的分类、规格、相应的测试方法以及过滤机理。针对SARS病毒的特性及传播途径 ,提出了所用口罩的要求和改善建议