Mechanical Engineering

Damping is the material's ability to dissipate elastic strain energy during cyclic loading. Materials with high damping capacity are significant in the present day scenario for transportation and other industrial applications. The development of materials with high damping capacity is one of the efficient measures to reduce vibrations, thereby noise. Low weight materials like aluminum and magnesium have excellent mechanical properties, but poor in damping.

The study has been done on the basis of questionnaire survey in the twenty-degree engineering colleges from West Bengal and foreign countries by random selection, ten colleges from each to measure the current or baseline performance level. The feedback for this questionnaire survey has been considered independently for service providers such as administrators, faculties, other supporting staff as well as students who receive these services and are direct customers. A total of 2168 persons have been surveyed from the 20 colleges. The baseline or current performance level of the colleges has been assessed based on the sigma level through quantification of the survey questionnaire consisting of eight enablers. Each enabler contains several questions or drivers. A seven-point scale has been designed for each driver ranging from “Unsatisfactory” to “Outstanding”.

Sand inclusion is an important defect in Cast Iron castings. On an average this defect is almost thirty to forty per cent of the total defects occurring in a foundry. Sand inclusion is undesirable since it results in reduction in the strength of the casting and bad finish of the casting surface. More than hundred parameters are responsible for sand inclusion and hence it is difficult to control defect during casting. A detailed Literature review of the previous work mostly on sand inclusion for almost last fifty years is done in this paper to find appropriate parameters for defect formation of sand inclusion. From the literature review it is found that the exact remedy for sand inclusion is not easy. The papers describing different techniques like Quality Function Deployment, cause and effect diagram, Design of Experiments etc. are also referred for finding the appropriate parameters responsible for sand inclusion. Corrective action should be taken on responsible parameters to eliminate the defect and improve quality of ferrous castings.

The present work deals with experimental studies on heat transfer and flow characteristic for buoyancy induced flow through inclined tubes. The parameters varied during the experimentation are; tube inclination and heat supply. It was found that mass flow rate and heat transfer coefficient increases with increase in heat flux supplied. The flow rate decreases for increase in tube inclination.

In the present day scenario rapid product development (RPD) becomes essential for product manufacturers for their survival. However, success of RPD depends on advancement and effective utilization of many more available technologies. Now with the availability of Computer Aided Design (CAD) / Computer Aided Manufacturing (CAM) for RPD making the demands of the present day industry are taken care. The product development by CAD/CAM reduces the considerable time of equipment and is made with higher accuracy and repeat-ability resulting in faster development of products and less rejection in the long run this approach to product developing results in cost effectiveness. This paper reviews the technological advancements in CAD/CAM Systems. This paper also depicts the lead-time reduction in product development through modeling with CAD/CAM and application of reverse engineering, Rapid prototyping and CNC approach to RPD.

Agricultural Machinery is mostly used in off road i.e. in the field. In the field these machines perform different field operations like Ploughing, where the parts are subjected to stresses like tensile stress, compressive stress and shear stress thereby high wear due to heavy loads. The critical components in the agriculture machinery are either forged or fabricated out of medium carbon steel by unorganized sectors in India. As a result the users suffer on account of quality and short service life of these components. Recently Austempered Ductile Iron (ADI) has come up which has high strength, high wear resistance and less manufacturing cost. This material is now being widely used in production of critical agricultural machinery components for cost effectiveness uses. The paper described the Mechanical, Tribological properties of Austempered ductile iron and its application areas in agricultural machinery in India and abroad.

Heat exchanger is a necessary laboratory equipment in a thermo-fluid laboratory, and lack of this equipment makes learning ineffective. Hence, this study aims to design and construct a shell and tube heat exchanger for laboratory use. To achieve this aim, mechanical and thermal factors were considered. The thermal design was done using the Bell Delaware method. The heat exchanger was designed based on the assumption that there is no phase change, while water at a cold inlet temperature of 15 °C enters the heat exchanger through the tube and hot water at 100 °C enters the heat exchanger through the shell. Results show that the geometry of the heat exchanger favours turbulent flow which enhances heat transfer. This causes a heat load of 107.973 kW to be transferred from the hot fluid to the cold fluid through the tube wall when hot fluid of 0.5 kg/sec flows at a velocity of 0.3 m/s and cold fluid of 2.58 kg/sec flows with a velocity of 1 m/sec. This heat transfer caused the cold fluid temperature to increase by 10 °C as it exits the tube, while the temperature of the hot fluid fell to 45 °C as it exits the shell. The pressure drops in both the shell and tubes were within the allowable range, and hence, accepted. With the overall heat coefficient at 134.23 W/m2K and the efficiency of the system at 73.3%, the study is said to have achieved its objective.

It has been found that the solar tree produces more energy than a conventional flat rooftop arrangement of solar PV system or modules. The solar energy converts the sunlight energy directly into electrical energy by making use of photo -voltaic or concentrated solar power. The energy demand is increasing with each period, as a result the grid electric supply unit prices are also increasing day by day. For example, with the supply of oil the quantity of oil is decreasing and the prices are increasing. Similarly in case of coal which is abundantly for the production of electricity is available for few more hundred years. So in order to fulfill the increasing demand of energy we must have some alternative sources of nonconventional sources of energy. The energy from the sun is the best alternative among all the renewable sources of energies. It is available free of cost, inexhaustible, non-polluting, eco-friendly and continuously. The main drawback of solar panels is the land requirement for the installation of solar panels. The developed solar artifact requires only 1% of the land compared to the flat rooftop to produce same amount of energy. A single converting cell or more generally known as a photo voltaic cell, but a combination of cells in series or parallel designed to increase the power output is called solar module or solar array. In this article the load capacity or energy requirement of a small house in India is estimated to 1.74kWhr/day [6]. All the calculations are done considering solar radiation data at Durgapur, West Bengal. As per experimentation it is found that tracking system can be easily employed in solar artifact, hence its performance will be better than flat solar PV system. The solar cells are mounted in a phyllotaxy pattern to avoid any obstruction from the others. Keywords: Solar artifact, phyllotaxy pattern, PV system, Solar module, manual tracking.

The need for eco friendly alternatives to conventional cutting fluids arises because usage of conventional cutting fluids poses threat to ecology and health of workers. The present work focuses on performance of nano solid lubricant suspensions in vegetable oils in turning of AISI1040 steel in minimum quantity lubrication(MQL). Soyabean, canola and coconut oils are taken as base lubricants with suspensions of 100nm sized boric acid particles. These particles are characterized by X-Ray Diffraction (XRD) and particle size analyzer to confirm their purity and particle size. Variation of basic properties like thermal conductivity, specific heat and heat transfer coefficient are evaluated from empirical relations, to check the viability of nano lubricants in machining. Variation of cutting tool temperatures, average tool flank wear and surface roughness of the machined surface with cutting speed and feed are studied with the prepared nano lubricants. Results are encouraging and coconut oil seems to be more advantageous compared to other vegetable oils.

This paper presents the failure analysis of the turbine blade of a gas turbine engine 9E GE type, installed in a certain type of simple systems consisting of the gas turbine driving an electrical power generator. A non-linear finite element method was utilised to determine the stress state of the blade segment under operating conditions. High stress zones were found at the region of the lower fir-tree slot, where the failure occurred. A computation was also performed with excessive rotational speed. Attention of this study is devoted to the mechanisms of damage of the turbine blade and also the critical high stress areas.