Distribution of mineral species in different coal seams of Talcher coalfield and its transformation behavior at varying temperatures

International Journal of Coal Science & Technology - Mineral phase characterization and thorough understanding of its transformation behavior during combustion are imperative to know the...     

Effect of Thermomechanical Fatigue on Precipitation Microstructure in Two Precipitation-Hardened Cast Aluminum Alloys

Thermal loading induces modifications of the precipitation microstructure of Al–Si–Cu–Mg alloys. This study focuses on the effect of deformation on precipitation microstructure during thermomechanical loadings. Several specimens were thermomechanically cycled while others were exposed to the same thermal cycles without any mechanical loading. The nature and morphological characteristics of the precipitation microstructure of the thermomechanically cycled specimens are compared to those of the thermally aged ones, using transmission electron microscopy (TEM), in order to assess the effect of deformation on the precipitation microstructure and especially on the kinetics of precipitate growth. The absence of any significant effect of superimposed straining during thermal cycling is discussed. Implications for the prevision of yield strength degradation during service operation are briefly presented.

     

Buckling-Induced Delamination of TiN Film on Stainless Steel in the Presence of Stress Concentration

TiN coating is provided by reactive magnetron coating on a 304 stainless steel sample with a notch introduced at the edge of the sample. The sample is subjected to a tensile stress close to that of yield strength of the stainless steel. Optical and scanning electron microscopy characterization showed the distribution of buckled and delaminated regions around the notch. The distribution of the size of the partially delaminated regions of the film on the substrate is determined by transient thermo-reflectance. The stress field due to the notch is represented by that of a circular hole present at the tip and the variation of compressive and shear strain as a function of radial and angular coordinates is determined. The distribution of buckled and delaminated regions is found to follow the compressive strain variation around the notch. The size of the partially delaminated film is found to be larger near the notch and decreased with distance from the notch. The results illustrate that structures with regions of stress concentration should not be provided with brittle protective coatings that will delaminate.

     

基于故障判别逻辑图的测试用例设计

本文通过分析故障判别逻辑图,研究了各电压等级智能站的测试用例最小数量,提出了一种自动生成测试用例的方法,结合具体工程应用实例,测试了用例的可行性。测试用例的生成提高了测试系统的工作效率,方便了工作人员的操作。     

Plastic Deformation Resistance of Steel Grades EP450-Sh and EP823-Sh in Hot and Cold State

Metallurgist - The article presents the results of plastometric studies on hot deformation and studies on the hardening curves in cold deformation of EP450-Sh (12H12M1BFR-Sh) and EP823-Sh...     

数据融合技术在变压器状态评估中的应用

电力变压器是电力系统及变电站的最至关重要的设备之一。对电力系统进行运行维护时,监测并预报变压器运行状态并且能够有效地监测并判断变压器的故障情况具有非常现实的意义。基于设备状态信息融合技术,分析了D-S证据理论的基本原理、组合规则和决策过程。通过具体的实例论述了诊断方法的具体可行性,比较了单一诊断方法(只经神经网络判断的结果)与信息融合技术的正确率,并指出信息融合技术的发展优势和可实现性。     

Cerium Effect on the Phase Composition and Crystallization Behavior of Aluminum Casting Alloys Based on the Al–Mg–Si System

Russian Journal of Non-Ferrous Metals - Using a Thermo-Calc software package (TCAl4.0 database), unexplored data concerning the phase composition and crystallization behavior of...     

Ensuring Strength in Laser Welds Made Using the Dispersion-Hardened EP693 Nickel Alloy

Russian Journal of Non-Ferrous Metals - The process of making a weld using the heat-resistant EP693 alloy (Ni–Cr–W–Co–Co–Mo system) to make assemblies and components...     

Production of Powdered α-Fe2O3 with Multilevel Gradient Porosity

Russian Journal of Non-Ferrous Metals - This article discusses methods for producing a material with gradient multilevel porosity by sintering layer-by-layer distributed α-Fe2O3 nanopowders...     

Laboratory study of impacts of concrete fragment sizes on wetland water chemistry

This study investigated the effects of urban concrete materials, of different particle sizes, immersed in water through a laboratory-based experiment. Water was sourced from a high conservation-value wetland (Blue Mountains upland swamp). Prior to the experiment, wetland water was dilute (32.5 μS/cm), acidic (pH 5.3) and had detectable major ion concentrations of only sodium and chloride. Water was exposed to three treatments of different concrete fragment sizes (whole, crushed and fine). All treatments increased conductivity and pH and also resulted in modified ionic composition where calcium, potassium, hydroxide, carbonate and sulphate were recorded at much high levels. The extent and speed of water chemistry changes was linked to the particle size of the concrete. The results of this study support the hypothesis that concrete can be an environmentally hazardous material influencing water quality in urban catchments.