EFFECTS OF WELDING CURRENT AND SPEED ON RESIDUAL STRESS AND DISTORTION OF JOINING ST52 ROLLED PLATE IN DIFFERENT WELDING SEQUENCES

Welding is a process of permanent joining parts by different welding methods. Residual stress and distortion are the most common phenomena of this process. Reduction of the residual stresses, distortion and improving the quality of welding are the important subjects of this field. Determining and analyzing the residual stresses and distortion is the main step for these purposes. Welding sequences, speed and current are the most effective parameters of this process. In this study, effects of welding parameters such as welding speed and current, in order to reduce residual stress and distortion of welding ST52 rolled plate in different welding sequences have been studied with three-dimensional thermo-mechanical finite element model by means of ANSYS APDL. By comparing different considered situations, the most efficient welding methods with the least residual stress and distortion by considering different welding sequences have been suggested. It obtains that welding the ST52 rolled plate from edge to edge with higher current and lower speed is the best option in fatigue and load-bearing situations, and welding from the center to both sides simultaneously with lower current and higher speed is the best option for assembly problems.

EXPERIMENTAL STUDY OF AIRBORNE DUST GENERATION DURING POWDER FREE FALLING

Powder handling produces airborne dust to the surrounding that can poses various hazards to peoples, industrial facilities and environment. This paper describes an experimental set up to examine the airborne dust generated in free falling of powders from a conveyor belt and investigates the influence of particle properties on the drop heights and conveying velocities to the formation of airborne dust. For this purpose, a dust generation measurement device was fabricated to quantify the amount of the airborne dust. It is found that the powder properties, drop height and conveying velocity have strong influence to the amount of airborne dust generated during free falling.

THE ASSESSMENT OF INHIBITIVE EFFECT OF CYMBOPOGON CITRATUS ON MARINE CORROSION OF MILD STEEL

Numerous extensive efforts have been done to acquire the applicable green corrosion inhibitors in order to decrease the corrosion rate of the materials. The corrosion inhibition of mild steel is vital for technology due to the increased industrial applications of these materials. In this report, the inhibitive action of Cymbopogon Citratus on the marine corrosion of mild steel was evaluated. The inhibition efficiency was calculated using weight loss measurement method, electrochemical measurement and inhibitor mechanism analysis. It was found that, Cymbopogon Citratus exhibited a very good performance as a green corrosion inhibitor for mild steel corrosion in seawater. All the experimental methods used for this project show that the presence of Cymbopogon Citratus in the seawater significantly decreases the corrosion rates and further decreasing the corrosion rates as the concentration of Cymbopogon Citratus increases. To sum it up, the inhibition efficiency increases with an increase in Cymbopogon Citratus concentration.

PERFORMANCE EVALUATION OF WHEAT STRAW CHOPPER BLOWER

The combine harvesters compete only with the crops, leaving large stubbles and machine-thrown straw on the ground. Removing wheat residues from the field can be very costly and laborious, farmers generally burn this left-over straw for cultivation operation of subsequent crop. Wheat straw chopper is an agricultural resource conservation environment friendly technology to collect stubbles from combine-harvested wheat fields. Currently, this technology is being used but, not evaluated in fields intensively. Therefore, the main the purpose of this study was to assess the wheat straw chopper output at Rana Agric after combine-harvested wheat, Jatoi estate, Punjab and the economies of this machine. Four different wheat varieties Sehar-2006, Lasani, Faisalabad-2008 and Punjab-2011 were in the test fields. Wheat straw chopper was operated with 75 hp tractor at two selected forward speeds 1.5 and 3.5km h-1. Results showed that the average effective field range of the chopper was 0.3 to 0.7 ha h-1 and 65 percent field efficiency. For the chaff the approximate volume recovered was 2234 kg ha-1. The running cost for the Chopper setup was $41.24 ha-1. The total value of the chaff and grain recovered was $216 ha-1 (@$0.1 kg-1) and $17.13 ha-1 (@$0.25 kg-1) respectively. The net savings for the wheat straw chopper were 192$ha-1. Wheat straw chopper has proven to be an effective technology which is gaining popularity in combined harvested wheat fields to save chaff and increase farmers ‘ income.

THE ROLE OF CONCAVE WALLS OF INNER CYLINDER ON NATURAL CONVECTION IN ANNULAR SPACE

The objective of the present research is to provide correct results of the roles of physical and geometrical parameters on the natural convection in an annular space of square cylinders. The physical parameters of the fluid are considered as follow: Prandtl number (0.71, 7.01, 50 and 100) and Rayleigh number (10 power 3, and 10 power 4). However, the studied geometrical modification is based on converting the walls of inner square cylinder from the straight form to the concave form. The work is well done numerically. The predicted results are mainly shown as representative contours of streamlines and isotherms. It was understood that the concave walls of inner cylinder reduces the heat transfer rate that can be useful to use this form in insulating applications instead of straight walls.

THERMAL STRESS ANALYSIS OF INTEGRATED COMBUSTION ENGINE PISTON USING CAE TOOLS (ALUMINUM SILICON ALLOY, ALUMINUM SILICON ALLOY STEEL)

The main indention of this research work is to investigate and analyze the stress distribution of piston at actual engine Condition. In this paper thermal stress analysis is done by two different materials Aluminum Silicon alloy and Aluminum Silicon alloy steel. The parameter used for the analysis is operating temperature and material properties of piston. In I.C(internal combustion) Engine piston is most complex and significant part therefore for smooth running of vehicle piston should be in proper working condition. Piston fails mainly Due to mechanical stresses and thermal stresses. Analysis of piston is done with boundary conditions and uneven temperature distribution from piston head to skirt. The analysis predicts that due to temperature whether the top surface of the piston may be damaged during the operating conditions, because damaged parts are so expensive to replace and generally are not easily available. The CAD model is created Using CATIA V5 R20 software. CAD model is then imported into ANSYS12 software for geometry and meshing purpose. The FEA Performed by also using ANSYS14.

IMPACTS OF AGRICULTURAL MECHANIZATION: A CASE OF PALPA DISTRICT OF NEPAL

A study was conducted in 2019 to assess the impacts of agriculture mechanization in Palpa district of Nepal. Two hundred and twenty farmers who have been the beneficiaries of mechanization programs launched by any of the three different tiers of government and other non-governmental organizations were selected randomly by adopting snowball method and interviewed. Majority (72.3%) of the farmers of the study area were found adopting mini tiller as the result of which the bullock driven plough was found almost replaced by it. Majority (92.7 %) of the farmers had experienced increase in cost of production for first and second year and decrease in cost of production afterwards. Most of the farmers experienced increase in working efficiency and improvement in the living standard after the adoption of machines in different agriculture operations. Agriculture mechanization was found having positive impacts in productivity of agriculture products because majority (89%) of the farmers experienced increase in productivity of their agriculture products after mechanization. Assuming those farmers who did not experienced any increase in productivity of their agriculture products (11%) as 100% majority (43.5 %) of them had pointed out lack of technical skills to operate machines as the major factor responsible for it. Therefore, the concerned authorities should be focused in proper arrangements of trainings and capacity building programs for farmers to operate those machines in addition to purchase and distribution of machines for the transformation of existing traditional agriculture into commercial, modern and mechanized agriculture.

EFFECTS OF WELDING PARAMETERS, TIME INTERVAL AND PREHEATING ON RESIDUAL STRESS AND DISTORTION OF JOINING ST52 STIFFENER RING IN AN AISI 4130 TUBULAR SHELL

Stiffener rings and stringers are used commonly in offshore and aerospace structures. Welding the stiffener to the structure causes the appearance of residual stress and distortion that leads to short-term and long-term negative effects. Residual stress and distortion of welding have destructive effects such as deformation, brittle fracture, and fatigue of the welded structures. This paper aims to investigate the effects of preheating, time interval and welding parameters such as welding current and speed on residual stress and distortion of joining an ST52-3N (DIN 1.0570) T-shape stiffener ring to an AISI 4130 (DIN 1.7218) thin-walled tubular shell by eleven pairs of welding line in both sides of the ring by means of finite element method (FEM). Results in tangent (longitudinal), axial and radial directions have been compared and the best welding methods proposed. After the comparison of the results, simultaneous welding both sides of the ring with preheating presented as the best method with less distortion and residual stresses among the studied conditions. The correctness of the FEM confirmed by the validation of the results.

STRUCTURAL, THERMAL AND THERMO-MECHANICAL ANALYSIS OF FOUR STROKE PETROL ENGINE PISTON USING CAE TOOLS

As we are known numerous reciprocating parts is contained in IC Engine which are responsible for giving the motion. The abnormal piston working is given poor performance in comparison of other parts. The main intention of this research is to investigate and analyse the stress distribution of automobile piston at definite engine Condition. In this paper pressure (Mechanical), thermal (Heat) and thermo-mechanical analysis is accomplished by help of CAE Tool. The constraint used for the analysis is pressure of operating gas, temperature and material properties of piston. In this research piston are designed for a single cylinder four stroke petrol engine using CATIA V5R20 and analysis is performed by ANSYS 14. Two different material are induced in this investigation. First one is Aluminium alloy and second is Cast Iron. In this end of the Results are shown and a comparison is made to find the most suited material for splendour automobile vehicle piston by various CAE analyses.

STRATEGIC EVALUATION IN OPTIMIZING THE INTERNAL SUPPLY CHAIN USING TOPSIS: EVIDENCE IN A COIL-WINDING MACHINE MANUFACTURER

Most of manufacturing firm aims to optimize their Supply Chain in-terms of improved profitability of their products through value Addition. This study takes a critical look into the factors that affect the Performance of internal supply chain with respect to specific criteria’s. Accordingly, ranking these factors to get the critical dimensions of supply chain performance in the manufacturing industry. A semi-structured interview with the pre-defined set of questions used to collect the responses from decision makers of the firm. Multi criteria decision-making tool called TOPSIS is used to evaluate the responses and rank the factors. The results of this indicate that supplier relationship and inventory planning were most principal factors positively influencing on-time delivery of the product, production flexibility, cost savings, additional costs. This study helps to identify and optimize the process parameters using objective and subjective evaluation approach. The combined influence of thought process of manager to optimize the internal supply chain is extracted in this work