Effect of Milling Medium on the Properties of Superconducting YBa2Cu3O7–x

Ball milling can be used for preparing large quantities of dense YBa₂Cu₃O₇. Studies of superconducting properties show that while a medium of alumina in hexane can be used to mix and to reduce particle size of the starting materials, it contaminates the reacted ceramic. Copper slugs produce an excess of Cu through wear, while balls made of partially stabilized zirconia produce the best results.     

Defect control at nanoscale and flux pinning enhancement in MgB2 superconductor

Railway Engineering Science - Defect control at nanoscale of MgB2 by doping various nanoparticles including Ti, C, nano-diamond, and HoB4, and their roles played to enhance flux pinning force in...     

Effects of AlPO4 addition on the corrosion resistance of andalusite-based low-cement castables with molten Al-alloy

This paper investigates the effects of AlPO₄ addition on the corrosion resistance of andalusite LCC refractories. Corrosion tests using the Alcoa cup test (850 °C and 1160 °C for 150 h and 72 h, respectively) were conducted to determine the extent of penetration. The addition of AlPO₄ was shown to improve the corrosion resistance of the castables in contact with molten Al-alloy. SEM/EDS analyses of the interfacial reaction zone showed the formation of corundum in the interfacial layer, along with a significant decrease in the phosphorus content in the interface. Thermodynamic calculations revealed that reaction with the alloy leads to the formation of corundum as the reaction product along with gaseous products (phosphorus trioxide gas) and small amounts of aluminum phosphide. Corundum formation at the interface enhances the corrosion resistance of sample due to high stability of corundum against molten Al alloy, while the metal quality is enhanced due to absence of dissolved phosphorus in the metal.     

Solar-hydrogen: Unresolved problems in solid-state science

The present work considers unresolved problems that need to be addressed for the development of photo-electrodes for photo-electrochemical generation of hydrogen from water using solar energy. The present work is focused on photo-electrodes based on oxide semiconductors, including TiO₂ and TiO₂-based materials, which are the most promising candidates for photo-electrodes. The properties of photo-sensitive oxide semiconductors are considered in terms of the concepts of photo-electrochemistry and the concepts of defect chemistry. The role of defect chemistry as a framework for the development of photo-electrode is considered. The effect of defect disorder on the performance-related properties of TiO₂-based photo-electrodes are discussed. The major challenges in the development of materials with optimized performance are considered in terms of both collective and local properties that must be assessed and modified simultaneously.     

Application of the risk oriented accident analysis methodology (ROAAM) to severe accident management in the AP600 advanced light water reactor

An important part of the AP600 design, as well as of the design certification review by the US Nuclear Regulatory Commission, is devoted to ensuring defense in depth through deep consideration and management of severe accidents. Going beyond the traditional Level 2 PRA, in this article we show how this defense in depth was achieved and demonstrated in a consistent manner between prevention and mitigation, through application of the Integrated ROAAM approach. This requires the up-front integration of probabilistic and deterministic thought, which leads naturally to clear and coherent safety goals as an overall guide toward closure.     

Effects of La- and Pr-Substitution on the Structure and Superconductivity of Ba0.6K0.4BiO3

利用熔盐法制备了Ba0.6-yLayK0.4BiO3和Ba0.6-zPrzK0.4BiO3 2个系列的样品,其中La和Pr的掺杂量y和z分别为 0, 0.025, 0.05, 0.1, 0.2, 0.3, 0.4。X射线粉末衍射结果显示,Pr掺杂使得BKBO晶体结构由最初的立方晶系转变成为正交晶系,但是La掺杂样品却没有发生此种晶体结构的变化。La掺杂样品Ba0.6-yLayK0.4BiO3的准晶格参数ap随掺杂量的增大而线性减小,其变化遵循ap = 4.28257–0.02469y (0.025 ≤ y ≤ 0.4)的规律。样品磁性测量结果表明,掺杂样品的超导转变温度Tc均随着掺杂量的增大而系统性地减小,并且当掺杂量达到0.2时,2个系统中的超导转变均消失。认为掺杂引起的晶体结构扭曲及铋化合价的不均衡导致了BKBO掺杂系统超导电性的变化。     

Improving the evidence base for energy policy: The role of systematic reviews

The concept of evidence-based policy and practice (EBPP) has gained increasing prominence in the UK over the last 10 years and now plays a dominant role in a number of policy areas, including healthcare, education, social work, criminal justice and urban regeneration. But despite this substantial, influential and growing activity, the concept remains largely unknown to policymakers and researchers within the energy field. This paper defines EBPP, identifies its key features and examines the potential role of systematic reviews of evidence in a particular area of policy. It summarises the methods through which systematic reviews are achieved; discusses their advantages and limitations; identifies the particular challenges they face in the energy policy area; and assesses whether and to what extent they can usefully be applied to contemporary energy policy questions. The concept is illustrated with reference to a proposed review of evidence for a ‘rebound effect’ from improved energy efficiency. The paper concludes that systematic reviews may only be appropriate for a subset of energy policy questions and that research-funding priorities may need to change if their use is to become more widespread.     

The economics of energy service contracts

Energy service contracting can provide a cost-effective route to overcoming barriers to energy efficiency. Energy service contracts allow the client to reduce operating costs, transfer risk and concentrate attention on core activities. However, the energy services model may only be appropriate for a subset of energy services and energy using organisations. A challenge for both business strategy and public policy is to identify those situations in which energy service contracting is most likely to be appropriate and the conditions under which it is most likely to succeed.