Influence of the method and degree of milling on the rate of milling and leaching of industrial alumina

Conclusions An investigation was made of the influence of the method and degree of milling on the time required to obtain a given mean particle size, and on the leaching of refired industrial alumina.It was found that much more time is required for milling of alumina in a ball mill than in a vibrational mill, the more so, the higher the temperature of the preliminary firing of the alumina. At the same time, the mean surface diameter of the powder increases, together with the content of grains of radius greater than 5, while the content of grains of radius less than 2, which is important to ensure good properties of the fired ceramic, decreases.During milling in a ball mill, the amount of ground iron is increased considerably compared with the amount during vibrational milling to the same particle size of the alumina.Leaching of alumina after milling in a ball mill is less satisfactory than after milling in a vibrational mill. As a result, the Al₂O₃ content in the washed material is decreased and the amount of Na₂O, Fe₂O₃, and other impurities is increased.Translated from Ogneupory, No. 1, pp. 43–50, January, 1969.     

面源污染中磷流失多重影响因素主成分分析

为全面了解对美国中部Illinois州具有浅层排水系统的轮作农业地区的面源污染问题,利用主成分分析方法及多元线性回归,对Little Vermillion River流域磷流失影响因素主成分进行分析.结果表明,磷流失的影响因素基本分为3大主成分:一是生物主成分,包括温度、植被类型、覆盖因子、生物量、散蒸量;二是水力主成分,降雨及流量;三是人为干扰主成分,施肥量及耕作内容.其中水力主成分对流失的影响最大,尤其是对浅层排水中磷流失的影响.     

Surveillance of Drinking Water Quality for Safe Water Supply—A Case Study from Shillong,India

To ascertain the quality of drinking water being supplied and maintained, it is necessary to conduct water quality surveillance for evolving suitable strategy for future planning. In the present investigation, water quality was monitored in treatment plants, service reservoirs, and at consumer ends in three seasons to assess the baseline water quality status at Shillong in Meghalaya. There are three water treatment plants at Shillong namely Umkhen, Mawlai and GSWS with design capacities of 1.5, 3.4 and 34 Million liter per day (MLD) respectively. Each treatment plant is having rapid sand filtration followed by disinfection. The study reveals that the physico-chemical parameters of water quality at consumer end meets Indian drinking water quality standards (BIS 1991) after conventional treatment followed by disinfection, whereas the bacteriological parameters for raw water sources exceed the permissible limit indicating the treatment need for drinking purposes. Throughout year the average feacal coliform contamination at service reservoir and to consumer end were found as 44 to 156 CFU/100 ml which may be attributed to the general management practices for maintenance of service reservoirs and the possibility of en route contamination.     

A comparative study on the metaheuristic-based optimization of skew composite laminates

Engineering with Computers - Plate structures are the integral parts of any maritime engineering platform. With the recent focus on composite structures, the need for optimizing their design and...     

Optimizing process parameters for laser beam micro-marking using genetic algorithm and particle swarm optimization

Laser micro-marking is an efficient technique for permanent marking and logo printing on materials. This study details the selection of an optimal parametric combination for laser micro-marking. In this work, markings were performed on Gallium Nitride (GaN) with varying the levels of marking parameters. The parameters considered in the present work are current (A), pulse frequency (Hz), and scanning speed (mm/sec). This experiment was designed using a “central composite design,” grounded in the response surface methodology. Mark intensity, which is a prominent response in laser marking, was considered the output response. The data interpretation involved analysis of variance (ANOVA) and mathematical modelling between the input parameters. It is essential to determine the relationship and significance of input-output variation. The interaction effect of various input parameters on mark intensity was also studied. Finally, two techniques, namely genetic algorithm (GA) and particle swarm optimization (PSO), were applied, and the optimal settings of input constraints were predicted.     

Design and Uncertainty Evaluation of a Strain Measurement System

Strain measurement is very important in various industrial applications as well as different disciplines of science and technology for direct and indirect observations of certain parameters. Designing signal conditioning circuit is always a challenging and important task for satisfactory and reliable performance of a sensor as well as the system. The design and implementation details of a signal conditioning circuit of resistive sensor (strain gauge) for strain measurement are presented in this paper. Also the important aspects in designing a signal conditioning circuit for resistive sensor are presented and a novel method for the measurement of strain is discussed. Quarter bridge configuration with AC voltage excitation is used for the measurement along with the necessary circuitry to get a suitable and measurable output DC voltage. The measurement system is calibrated using a cantilever of stainless steel and the details of calibration are presented in the paper. The uncertainty associated with the measurement system is evaluated.     

Creation of TiN paths on titanium alloy OT4-1 by the use of a laser beam

TiN paths have been created on the surface of the titanium alloy OT4-1 by the use of a laser beam. The results of investigations of structure, phase composition, microhardness and surface roughness of the created TiN paths are given in the paper. The paths created in the work are inhomogenous two-phase mixtures of TiN and -Ti, in which the TiN phase with strong (2 0 0) texture is predominant over the other phase and presents a dendritic structure. © 1998 Chapman & Hall     

Development of a Virtual Reality Structural Analysis System

This paper discusses the development of virtual structural analysis program (VSAP). This is a virtual environment (VE) based structural analysis system developed through a collaborative effort between the School of Architecture + Design and the Department of Computer Science at Virginia Polytechnic Institute and State Univ. (Virginia Tech). The VSAP was developed by linking a visualization routine using the simple VE library and a structural analysis software, the PC-SAP4. Details of the design of four user interfaces for the VSAP are presented. These user interfaces are: the immersive pen and tablet interface, the desktop interface, the portable immersive interface, and the cave automatic VE immersive interface. Usability studies for each interface were conducted. Results of these studies indicated that the users of VSAP were highly satisfied with the experience. In addition, all the developed interfaces were found to be successful for their specific application.     

Evaluation of Optimal River Training Work Using GA Based Linked Simulation-Optimization Approach

Use of structural measures for controlling a river to minimize its devastating effect and to utilize it for the benefit of mankind is a common practice all over the world. Because of high investment, such measures require prior investigation through model study. As lab based physical model study is very expensive and time consuming, mathematical modeling is generally used for investigating different alternatives of river training works. In this study, a new approach is proposed for deciding appropriate river training measure in a particular reach of a river or channel. In this methodology, an optimization model is linked with the hydrodynamic model for obtaining cost effective combination of groynes which will maintain a user defined flow speed in a pre-decided portion of a river reach. The optimization model is developed using binary coded Genetic Algorithm (GA) and the flow simulation model uses the Beam and Warming scheme for solving the two dimensional (2D) hydrodynamic equations of unsteady flow. The performance of the model is tested by applying the methodology in a rectangular channel for attaining different target speed values at a pre-defined portion of the channel and logical results have been obtained for all the tested scenarios.     

The Effect of Thermal Treatment Modes on the Structure and Corrosion Resistance of Plasma Coatings Made of Alloys Based on Nickel and Iron

Protection of Metals and Physical Chemistry of Surfaces - The structural state and corrosion resistance of the plasma coatings based on iron (FBKh6-2 alloy) and nickel (RW 12496 alloy from Castolin...