Corrosion behavior analyses of metallic membranes in hydrogen iodide environment for iodine-sulfur thermochemical cycle of hydrogen production

HI decomposition in Iodine-Sulfur (IS) thermochemical process for hydrogen production is one of the critical steps, which suffers from low equilibrium conversion as well as highly corrosive environment. Corrosion-resistant metal membrane reactor is proposed to be a process intensification tool, which can enable efficient HI decomposition by enhancing the equilibrium conversion value. Here we report corrosion resistance studies on tantalum, niobium and palladium membranes, along with their comparative evaluation. Thin layer each of tantalum, palladium and niobium was coated on tubular alumina support of length 250 mm and 10 mm OD using DC sputter deposition technique. Small pieces of the coated tubes were subject to immersion coupon tests in HI-water environment (57 wt% HI in water) at a temperature of 125–130 °C under reflux environment, and simulated HI decomposition environment at 450 °C. The unexposed and exposed cut pieces were analyzed using scanning electron microscope (SEM), energy dispersive X-ray (EDX) and secondary ion mass spectrometer (SIMS). The extent of leaching of metal into liquid HI was quantified using inductively coupled plasma-mass spectrometer (ICP-MS). Findings confirmed that tantalum is the most resistant membrane material in HI environment (liquid and gas) followed by niobium and palladium.     

测试测量与医学成像领域的模拟技术趋势

架构领域的系统集成及发展是未来电子市场成功的关键.实现成功的主要目标包括:使产品外型更小、功能更多、功耗更低,并且成本也更低.未来的集成解决方案将以当今的分离式解决方案为开发基础.制造商利用工艺技术推动市场发展,向市场提供集成度更高的产品,在缩小尺寸、降低功耗及成本、提高可靠性的同时提高性能.     

Environmental science research in India: An analysis of publications

Investigates the trends in environmental science research in India with regard to its various branches, channels of communication used, authorship pattern of the papers, institution-wise output, rank of journals, extent of collaboration and scholarship of papers basing the entries noticed in theParyavaran Abstracts. Major areas of interest of Indian environmentalists are given and prolific investigators have been listed. Journals used by Indian workers for publication of their work are studied. Subject areas with number of papers, number of authors, and average authorship are tabulated.     

Laser backscattering and transillumination imaging of human tissues and their equivalent phantoms

Surface backscattering profiles from a human forearm and transmission profiles through a human thumb, of red and near-infrared lasers, were determined. For the preparation of tissue-equivalent phantoms, white paraffin wax mixed with various wax color pigments were used. The surface reflectance profiles of a human forearm were matched with that of the phantom by mixing color pigments in various proportions. The reconstructed surface reflectance image of the phantom prepared by this procedure was similar to that of the human forearm. The transmission tomogram of the human thumb was obtained in fan-beam configuration by a near-infrared laser tomography system. Based on the horizontal scan of this tomogram, a two-layered phantom was made. The color composition of the phantom was so adjusted that its horizontal scan was matched with that of the thumb tomogram. The phantoms of complex tissues, prepared by this procedure, could be used for evaluation and calibration of new optical diagnostic imaging techniques.     

全差分放大器(一)

差分信号固有的外部噪声抑制特性使其多年来普遍应用于音频、数据传输和电话系统。如今，差分信号技术正在高速数据采集领域日益普及，这种应用场合中ADC带有差分输入，需要差分放大器来驱动。差分信号还可减少偶次谐波和增加动态范围。重点讨论集成全差分放大器的结构、电压定义及应用（包括与差分ADC输入的接口电路，抗混叠滤波器以及驱动传榆线）。     

Airflow distribution through perforated tiles in raised-floor data centers

Raised-floor data centers are the most commonly used facilities for housing computer and telecommunication equipment. To adequately cool this equipment, the cooling air through perforated tiles must be distributed properly. The airflow distribution depends on the pressure distribution or the flow field in the space under the raised floor (plenum); it is a complex function of a large number of variables, including the size of the plenum, the open area of the perforated tiles, the locations and flow rates of the computer room air conditioner (CRAC) units, and the size and location of the under-floor obstructions like cables and pipes. In this article, the effect of these parameters on the airflow distribution is studied using an idealized one-dimensional computational model. Within the one-dimensional framework, the airflow distribution is governed by two dimensionless parameters: one related to the pressure variation in the plenum and the other to the frictional resistance. Results, in terms of distributions of pressure in the plenum and flow rates through the perforated tiles, are presented over a range of values of these two parameters. These results provide an understanding of the fundamental fluid mechanical processes controlling the airflow distribution through the perforated tiles. The one-dimensional model is used to calculate flow rates for two possible arrangements of the CRAC units, and these results are compared with those given by a three-dimensional model.     

Temperature and Material Flow Prediction in Friction-Stir Spot Welding of Advanced High-Strength Steel

Friction-stir spot welding (FSSW) has been shown to be capable of joining advanced high-strength steel, with its flexibility in controlling the heat of welding and the resulting microstructure of the joint. This makes FSSW a potential alternative to resistance spot welding if tool life is sufficiently high, and if machine spindle loads are sufficiently low that the process can be implemented on an industrial robot. Robots for spot welding can typically sustain vertical loads of about 8 kN, but FSSW at tool speeds of less than 3000 rpm cause loads that are too high, in the range of 11–14 kN. Therefore, in the current work, tool speeds of 5000 rpm were employed to generate heat more quickly and to reduce welding loads to acceptable levels. Si₃N₄ tools were used for the welding experiments on 1.2-mm DP 980 steel. The FSSW process was modeled with a finite element approach using the Forge^® software. An updated Lagrangian scheme with explicit time integration was employed to predict the flow of the sheet material, subjected to boundary conditions of a rotating tool and a fixed backing plate. Material flow was calculated from a velocity field that is two-dimensional, but heat generated by friction was computed by a novel approach, where the rotational velocity component imparted to the sheet by the tool surface was included in the thermal boundary conditions. An isotropic, viscoplastic Norton-Hoff law was used to compute the material flow stress as a function of strain, strain rate, and temperature. The model predicted welding temperatures to within 4%, and the position of the joint interface to within 10%, of the experimental results.     

Polycaprolactone/Graphene Oxide–Silver Nanocomposite: A Multifunctional Agent for Biomedical Applications

Journal of Inorganic and Organometallic Polymers and Materials - In recent times, the global demand for multi-biofunctional tissue scaffolds is rising gradually. The present study deals with the...     

Plastic Deformation in a Molecular Crystal Enables a Piezoresistive Response

Organic materials are promising candidates for the development of efficient sensors for many medicinal and materials science applications. Single crystals of a small molecule, 4-trifluoromethyl phenyl isothiocyanate (4CFNCS), exhibit plastic deformation when bent, twisted, or coiled. Synchrotron micro-focus X-ray diffraction mapping of the bent region of the crystal confirms the mechanism of deformation. The crystals are incorporated into a flexible piezoresistive sensor using a composite constituting PEDOT: PSS/4CFNCS, which shows an impressive performance at high-pressure ranges (sensitivity 0.08 kPa⁻¹ above 44 kPa).