Multi-response optimization in machining: exploration of TOPSIS and Deng’s similarity based approach

Machining deals with removal of unwanted material from the work piece in the form of chips in order to get required dimension. Consumption of energy, wastage of material, requirement of skilled person etc. make the process expensive. Hence, machining industries have to face the inevitable challenge to reduce cost as well as to machine material within the tolerance limit which can be accepted by the customers. The output characteristics like Material Removal Rate (MRR), surface roughness, tool wear, tool life, cutting temperature, cutting force etc. are greatly influenced by the input cutting parameters like speed, feed rate, depth of cut etc. Therefore, selection of cutting parameter plays an important role for a sound production. Optimization techniques are quite helpful for selection of appropriate cutting parameters through offline check. The industries have to concern about a number of performance characteristics simultaneously because focus on a single objective may appear as loss for rest of the objectives, and, hence, multi-objective optimization techniques may be suitable. In the present work, turning operation of aluminum was carried out using a HSS tool on a lathe machine. Cutting parameters: speed, feed rate, and depth of cut was varied at five different levels; Taguchi method was employed for designing a L25 orthogonal array. The output performances viz. MRR, surface roughness, cutting temperature, and cutting forces were recorded for each run. Deng’s similarity based method and TOPSIS (integrated with Taguchi method) were explored for determining appropriate process environment (parameter setting) for simultaneous optimization of multiple process-performance-yields

Mineralogical Characterization of Iron Ores

Mineralogical characterization of iron ore is a very important and basic aspect that has to get due attention before any attempt for its processing and has become almost inevitable these days because of the increasing demand of the ore. Mineral processing technology is evol-ved to separate and recover ore minerals from gangue in a commercially viable method and is mainly based on the process of mineral liberation and the process of mineral separation. Therefore, it is important to first get a clear understanding about ore- and gangue minerals. A mineral is a natural inorganic substance having definite chemical composition and atomic structure. If the internal atomic arrangement is lacking, then it is an amorphous substance. A rock is generally composed of various mine-rals and if the rock contains valuable minerals from which metals can be extracted at a profit, it is called n 'ore'. The unwanted mineral in an ore is called gangue (i.e., generally rock forming minerals). For example, hematite (Fe203) and magnetite (Fe304) are oxides of iron and are ore forming minerals. In iron-ore, these minerals gene-rally dominate but other unwanted minerals that occur are quartz (Si02), kaolinite (clay) etc., are gangue minerals. The terminologies `ore' and 'gangue' are subjective. For example in a mine, when the ore/rock is mined with an objective to extract iron, hematite is the desired mineral and is called ore. The same mineral hematite if found in a sulfide ore (that is being mined to extract Pb, Zn or Cu) is called gangue. Therefore, `ore' and `gangue' terminologies can broadly be assumed as the desired and `undesired' material in a rock mass respectively. Even though ore is mined with the highest efficiency of the technology, the excavated ore gets partly contaminated by the surrounding host rock (overburden) and the geol-ogical material closely associated with the ore during mining. Both the materials are undesirable and hence form the gangue

Gold in the Beach Placer Sands of Chavakkad-Ponnani, Kerala Coast, India

Although sporadic mining of placer gold from river beds is not uncommon in India, there is no documented literature on the occurrence of gold in the beach placer sand deposits of the country. While characterizing the heavy minerals of the Chavakkad-Ponnani (CP) beach placer sands along the North Kerala coast, the association of gold with the pyriboles in these sands has been observed. A native gold grain of about 25 micrometer was seen to occur as an inclusion within an amphibole of hornblendic composition. The pyriboles of the CP deposit are angular to sub-angular indicating a nearby provenance that may be in the upstream reaches of the Ponnani river in the districts of Malappuram and Palakkad or further north in the auriferous tracts of the Wynad-Nilambur or Attapadi regions. It is argued that the occurrence of native gold in CP deposit is not a freak occurrence and that it warrants thorough investigation of all the pyribole-ilmenite-rich placers to examine the possible presence of gold and its abundance in the beach placers of northern Kerala coast

Teaching of Critical Analysis of Drug Advertisements to Medical Students

Background: Medical practitioners utilize drug promotional materials from pharmaceutical companies as a major source of information especially in developing countries. These promotional materials can be highly informative as long as they are critically appraised but when they are accepted without question, they lead to irrational prescribing. Aim: To sensitize the students regarding WHO criteria for medicinal drug promotion and to determine the impact of teaching critical appraisal of medicinal drug promotion to medical students. Design: The medical students of second year were given a pre test questionnaire to identify the violations in generic labeling, pharmacological information, claims, relevance and references cited in the drug advertisements. Later they were sensitized about the WHO criteria for medicinal drug promotion and how to critically appraise a drug advertisement. This was followed by a post test questionnaire with the same drug advertisement. Result: The number of students answering the post test correctly was significantly (p<0.05) more than that of pre test. Conclusion: Education of medical students regarding critical analysis of drug advertisements should be a part of the medical curriculum

Study of electronic properties of III-V semiconductors and semiconductor-superlattices

We have studied different methods for calculating band structures of solids and their density of states which can predict the electronic properties of solids accurately. Especially, computational methods like tight binding approximation and pseudo potential method have been studied and applied to find the band structures and density of states of semiconductors and its superlattices. The project work is divided into two parts. In first part, pseudo potential method has been used to solve computationally by MATLAB, the energy Eigen values of III-V semiconductors like GaAs and AlAs and IV semiconductor i.e. Ge and get a graphical representation of their band structures. In second part, TB-LMTO program which uses tight binding method has been applied to find the band structures and density of states of GaAs and AlAs semiconductors and their superlattices (GaAs/AlAs). A comparison of conducting behaviour of these materials is made finally