Block truncation coding with color clumps: A novel feature extraction technique for content based image classification

The paper has explored principle of block truncation coding (BTC) as a means to perform feature extraction for content based image classification. A variation of block truncation coding, named BTC with color clumps has been implemented in this work to generate feature vectors. Classification performance with the proposed technique of feature extraction has been compared to existing techniques. Two widely used public dataset named Wang dataset and Caltech dataset have been used for analyses and comparisons of classification performances based on four different metrics. The study has established BTC with color clumps as an effective alternative for feature extraction compared to existing methods. The experiments were carried out in RGB color space. Two different categories of classifiers viz. K Nearest Neighbor (KNN) Classifier and RIDOR Classifier were used to measure the classification performances. A paired t test was conducted to establish the statistical significance of the findings. Evaluation of classifier algorithms were done in receiver operating characteristic (ROC) space.     

New pseudo-dynamic analysis of two-layered cohesive-friction soil slope and its numerical validation

Natural slopes consist of non-homogeneous soil profiles with distinct characteristics from slopes made of homogeneous soil. In this study, the limit equilibrium modified pseudo-dynamic method is used to analyze the stability of two-layered c-φ soil slopes in which the failure surface is assumed to be a logarithmic spiral. The zero-stress boundary condition at the ground surface under the seismic loading condition is satisfied. New formulations derived from an analytical method are proposed for the predicting the seismic response in two-layered soil. A detailed parametric study was performed in which various parameters (seismic accelerations, damping, cohesion, and angle of internal friction) were varied. The results of the present method were compared with those in the available literature. The present analytical analysis was also verified against the finite element analysis results.     

Conjugation and H ∞ control of discrete-time systems

We establish conjugation notion in discrete-time systems, first introduced into the H ^∞ control theory of continuous-time systems by Kimura (1989). In discrete-time systems, conjugation is a very elementary operation on rational transfer functions that replaces some of their poles by their reflections with respect to the unit circle. With the aid of J-lossless conjugation conjugation by a J.lossless system), it is shown that the parametrization of sub-optimal solutions of H ^∞ model-matching problems is reduced to a Lyapunov-type equation. The parametrization of all solutions is given in an extremely simple way. It is further proved that the J-lossless conjugation of the H ^∞ model-matching problem is a natural state-space representation of classical interpolation in discrete-time systems.     

氨浸出混合铜矿石的表征及动力学(英文)

研究了含8.8%Cu和36.1%Fe的混合铜矿石的氨浸出动力学。矿物学表征表明,该矿石的含铁成分以菱铁矿为主,硫化矿以黄铜矿为主。研究了工艺参数,如搅拌速度、反应温度、氨浓度、矿石粒径、氧分压对氨浸出过程的影响。在标准的浸出条件下,即粒径125~212μm、反应温度120°C、NH3浓度1.29 mol/L、氧分压202 kPa,在2.5 h内Cu的浸出率达到83%。在使用较高浓度的氨和较小粒径的矿石时,Cu的浸出率能够达到95%。动力学研究结果表明,浸出过程为表面反应控制,估算出的活化能为(37.6±1.9)kJ/mol,氧分压与氨浓度的反应级数分别为0.2和1。     

Crack resistance of austenitic stainless steel pipe and pipe welds with a circumferential crack under monotonic loading

This paper describes the experimental studies carried out on cracked austenitic stainless steel pipe and pipe welds under bending loads. Pipe welds were produced by gas tungsten arc welding (GTAW) and shielded metal arc welding (SMAW). Fracture resistance curves for pipe and pipe welds were compared. Results indicate that the fracture resistance of pipe and pipe weld (GTAW) is comparable but that of pipe weld (GTAW+SMAW) is inferior. Cracks do not deviate from their original plane during propagation as observed in the cases of carbon steel pipe and pipe welds. The fracture resistance of pipe welds does not depend on the loading histories to which it has been subjected prior to fracture test. Initiation and crack propagation were observed prior to the maximum moment. An existing limit load expression is applicable for the pipe base material but gives non‐conservative results for the pipe welds. Multiplication factors have been suggested for the pipe welds for evaluation of limit loads using the existing expression. Fracture resistance for the pipe and compact tension specimens have also been compared for base material and welds.     

DISPERSION STATE OF PROTEIN-STABILIZED EMULSIONS

The stability of concentrated benzene-in-water emulsions emulsified by bovine serum albumin (BSA) in the presence of various concentrations of sodium chloride has been measured in the light of the coalescence kinetics. On the acid and alkaline sides of the isoelectric point of BSA (pH 4.9), the rate of coalescence between globules decreased and approached that at the isoelectric point of BSA with increasing concentrations of sodium chloride. In these systems, the interfacial tension at the benzene/aqueous BSA solution interface, and the globule size distribution in the emulsions, reached the values observed at the isoelectric point when the concentration of sodium chloride was above about 50 mM. The role of the adsorbed film of BSA on the surface of dispersed globules is considered in relation to the dissociation state of the BSA molecules.     

Environmentally assisted cracking resistance of Al–Cu–Li alloy AA2195 using slow strain rate test in 3.5% NaCl solution

The general corrosion and environmental cracking resistances of Al–Cu–Li alloy AA2195 were investigated in 3.5% NaCl environment and compared with those of another high strength alloy AA2219. The general corrosion resistance of these alloys was examined using immersion corrosion and potentiodynamic polarization tests, while the stress corrosion cracking (SCC) resistance was evaluated by slow strain rate test (SSRT) method. The tested samples were further characterized by SEM–EDS and optical profilometry to study the change in corrosion morphology, elemental content and depth of corrosion attack. The reduction in ductility was used as a parameter to evaluate the SCC susceptibility of the alloys. The results indicated that the corrosion resistance of AA2195 alloy was better than that of AA2219 alloy as it exhibited lower corrosion rate, along with lower pit depth and density. However, the SCC index (?_NaCl/?_air) measured was greater than 0.90, indicating good environmental cracking resistance of both the alloys. Detailed fractography of the failed samples under SEM–EDS, in general, revealed a typical ductile cracking morphology for both the alloys.     

尼日利亚钛铁矿的矿物学特征和浸出行为

研究尼日利亚钛铁矿矿物学特征和经机械活化和碱性焙烧处理后的浸出行为。研究了 NaOH/矿石比、H2SO4浓度、浸出和焙烧温度对钛回收率的影响。结果表明,机械活化对钛铁矿石的浸出有明显的增强作用。钛铁矿经机械活化后,加入60%NaOH在850°C下焙烧,在温度为90°C,经60%H2SO4浸出4 h下的浸出率为72%。对焙烧矿、水处理后残渣和酸浸滤渣的XRD物相分析证实了反应机理和实验结果。     

不同热处理态2024铝合金的腐蚀行为

分别在3.5%NaCl溶液、3.5%NaCl＋1.0%H2O2溶液和pH=12的3.5%NaCl溶液中进行动电位极化实验,研究2024 Al-Cu-Mg合金在不同热处理状态下的腐蚀行为。极化曲线表明,随着合金时效时间的延长,合金的腐蚀电位向负方向移动;向NaCl溶液中添加H2O2会使腐蚀电位正移;在pH=12的3.5%NaCl溶液中的极化曲线表现出明显的钝化现象。腐蚀试样表面表现为常见的腐蚀特征,但也有扩大的点蚀、晶间腐蚀现象出现。循环动电位极化曲线显示有宽的循环极化滞后环,不同的腐蚀模式表明合金的点蚀生长对合金的热处理状态敏感。通过显微组织分析,探讨了不同热处理状态下合金在不同NaCl溶液中的腐蚀机理。