Rate of nitrogen desorption from liquid iron-carbon and iron-chromium alloys with argon

The rate of nitrogen desorption from inductively stirred liquid iron, iron-carbon, and iron-chromium alloys with argon carrier gas has been measured by the sampling method for a wide range of nitrogen, carbon, and chromium contents mainly at 1600 °C. The results obtained by the present work and other data of previous investigators are used to clarify the reaction mechanism of nitrogen desorption from liquid iron. The rate of nitrogen desorption from liquid iron and iron alloys is second order with respect to nitrogen content in the metal under the present condition, and mutual relationships among interfacial chemical reaction, liquid-phase mass transfer, and gas-phase mass transfer are elucidated. The effects of oxygen and sulfur on the rate of nitrogen desorption are given byk _' ^{c ’} = 3.15?_N ² [1/(1 + 300a₀ + 130a_s)]. Carbon dissolved in iron increases the rate of nitrogen desorption, and chromium decreases it. The effects of these alloying elements can be explained by the change of the nitrogen activity in the metal.     

Toughened glass-ceramics in the ZrO2-Al2O3-SiO2 system prepared by the sol-gel process

Monolithic glass-ceramics containing Al₂O₃ or TiO₂ were prepared in the ZrO₂-SiO₂ system by the sol-gel process from metal alkoxides. Tetragonal ZrO₂ was precipitated by heat treatment at 900–1200 °C and its crystal growth was increased by adding TiO₂ or Al₂O₃. Further heating at higher temperature resulted in the precipitation of zircon and monoclinic ZrO₂ which was transformed from tetragonal ZrO₂. The addition of Al₂O₃ had less effect on both the tetragonal-to-monoclinic ZrO₂ transformation and the precipitation of zircon. The fracture toughness increased as the size of tetragonal ZrO₂ particles increased and then decreased with the appearance of monoclinic ZrO₂ or zircon. The fracture toughness of the glass-ceramics was measured in the glass-forming regions of the ZrO₂-Al₂O₃-SiO₂ system. The fracture toughness was sensitively dependent on both Al₂O₃ and ZrO₂ content, of which the highest value achieved was 9 MPa m^1/2 for the 50ZrO₂·10Al₂O₃·40SiO₂ composition.     

Simultaneous measurement of surface tension and kinematic viscosity using thermal fluctuations

We have developed a surface laser-light scattering apparatus to measure simultaneously surface tension and kinematic viscosity. In this method, we can obtain the surface properties by the laser heterodyne detection of light scattered from thermally excited capillary waves (called ripplon), which are typically of low amplitude (1 nm) and a characteristic wavelength (100m). Two gratings (d=100 and 200m) were employed to select the wave number of the capillary waves and to produce a reference beam for heterodyne detection. It was found through an experimental study on water that this contact-free method has considerable potential for application to measurements under extreme conditions such as high temperatures and high pressures.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

Development of a micro optical diffusion sensor using laser‐induced dielectrophoretic manipulation

We have developed a novel micro optical diffusion sensor (MODS) based on laser‐induced dielectrophoresis (LIDEP), which enables rapid measurement with a small sample volume and on‐site sensing of protein conformation. This paper presents the measurement principle, the chip design, and the validity of the proposed method. To verify the applicability of MODS, we confirmed a sinusoidal concentration distribution of polystyrene beads in a surface‐modified microchannel generated by LIDEP force. The decay time of the diffusion of the concentration distribution agreed well with theoretical calculations, confirming the applicability of MODS as a technique for measuring the diffusion coefficient. © 2010 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20303     

EPA and DHA Status of South Asian and White Canadians Living in the National Capital Region of Canada

To minimize the risk of cardiovascular disease (CVD), most dietary guidelines have recommended consuming 500 mg/day of eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) or two servings of oily fish/week. The sum of percent EPA and DHA in red blood cell (RBC) total fatty acids-termed the omega-3 index-has been proposed as a biomarker for assessing the risk of death from CVD. The omega-3 indices of ≤4, >4 to <8 and ≥8 % have been proposed to be associated with high, intermediate and low CVD risks, respectively. In this study, we determined the EPA + DHA intake level and the omega-3 index of South Asian Canadians (SAC; n = 308) and white Canadians (WC; n = 341) age 20–79 years living in the National Capital Region of Canada. The mean EPA + DHA intake levels were 569 ± 571 mg/day for SAC and 684 ± 865 mg/day for WC and 46 % of SAC and 43 % of WC met the recommended EPA + DHA intake level of 500 mg/day. The mean omega-3 indices were 6.6 and 5.9 % for SAC and WC respectively. The suggested cardio-protective target level for the omega-3 index of ≥8 % was observed only in 19.8 % of SAC and in 9.4 % of WC subjects. The majority of the participants (74.4 % of SAC and 82.7 % of WC) were in the >4 to <8 % range. These results suggest that although study participants’ dietary intake of EPA + DHA is adequate, this intake was not sufficient to provide an omega-3 index that is considered cardio-protective.     

Application of B MAS-NMR to the characterization of boron in coal fly ash generated from Nantun coal

Boron and its compounds are environmentally hazardous substance and are well-known condensed products that appear in coal fly ash during combustion of coal in coal-fired electric power stations. In a previous study, we suggested that boron in coal fly ash obtained from Nantun coal in China, identified as Ash-N, may exist on the surface of relatively large coal fly ash particles or as very fine particles generated by homogeneous nucleation. Although the characterization of boron in coal fly ash is important for its effective stabilization or removal, its detection is quite difficult because of its low concentration in coal fly ash and its light atomic weight. In the present work, solid-state magic angle spinning nuclear magnetic resonance (MAS-NMR) technique has been applied to reveal the local chemical structures of boron in Ash-N. In the ¹¹B MAS-NMR spectrum of Ash-N, two peaks which are attributed to a three-oxygen coordinated boron unit (BO₃) and a four-oxygen coordinated boron unit (BO₄) were observed with high resolution. We have estimated quadrupole parameters of the BO₃ unit in Ash-N using computer simulation, and we have fingerprinted these moieties with the parameters of borates. The result of the present analysis shows that calcium- or magnesium-bearing orthoborate or pyroborate are the most likely forms of boron in Ash-N.     

A novel high-torque reluctance motor with rare-earth magnet

An entirely new concept of an electromagnetic structure which exploits the excellent characteristics of a rare-earth magnet is proposed. Thin rare-earth metal magnet pieces are mounted on the surface of the stator teeth which face the airgap. The rotor has a variable reluctance structure type. This type of motor is suitable for low-speed high-torque applications by the action of tooth and slot structure. The relationship between the performance and electromagnetic geometry is investigated through the finite element method (FEM) analysis and experiments. The principle of torque generation and the associated characteristics is also introduced     

Welding techniques development of CLAM steel for Test Blanket Module

Fabrication techniques for Test Blanket Module (TBM) with CLAM are being under development. Effect of surface preparation on the HIP diffusion bonding joints was studied and good joints with Charpy impact absorbed energy close to that of base metal have been obtained. The mechanical properties test showed that effect of HIP process on the mechanical properties of base metal was little. Uniaxial diffusion bonding experiments were carried out to study the effect of temperature on microstructure and mechanical properties. And preliminary experiments on Electron Beam Welding (EBW), Tungsten Inert Gas (TIG) Welding and Laser Beam Welding (LBW) were performed to find proper welding techniques to assemble the TBM. In addition, the thermal processes assessed with a Gleeble thermal-mechanical machine were carried out as well to assist the fusion welding research.     

中国低活化马氏体钢CLAM研究进展

低活化铁素体/马氏体钢(RAFM钢)被普遍认为是未来聚变示范堆和聚变动力堆的首选结构材料。国际上给予了高度重视,许多国家都在研发其特有的RAFM钢。中科院等离子体物理研究所在与国内外多家单位的合作下发展了中国低活化马氏体钢———CLAM。本文总结了CLAM钢研制发展的主要进展,包括其成分优化设计、冶炼加工制备工艺、物理性能、机械性能、辐照性能及与液态LiPb的相容性等测试与研究以及各种焊接工艺研究等,并对今后的发展方向进行了展望。