Mechanical Engineering

One of the most important factors for agricultural mechanization is management of repair and maintenance costs. Today, tractor is one of the main sources of power in agriculture. The engine overhaul cost is the most rates of repair and maintenance costs. Suitable and high quality engine oil consumption is a more effective factor on engine life increasing. The Nano-science is a new effective method to improving the quality of engine oil and controlling of costs. This study was carried to evaluate the impact of Nano-diamond as an engine oil additive on increasing the oil quality and wearing reduction in the engine oil components. For this purpose, 10 Massey Ferguson 399 tractors were selected from the common tractors in Iran and were classified in two groups. The Nano-diamond as an oil additive material was added to engine oil in one group and was used pure engine oil (without adding any additive) in other one. Then the oil sampling were carried on all tractors engine oil at 50, 100 and 120 hours service time durations and elemental analysis were completely performed on samples. The data were analyzed by SPSS software. Results showed a significant difference at 5% level, between the two groups based on the life oil additives as well as the quantity of erosion particles. The results showed that it is effective to increasing of engine lubricant oil quality as well as reducing of erosion particles quantity, when this additive is used whit 1% concentration based on weight in MF 399 engine lubricant oil tractor. Additionally, resulting from hard Nano-diamond structure, some of the large ferrous particles observed that their quantities have been decreased gradually.

Evaluation of 20 min. shot peening surface treatment on fatigue strength of 6063-T6 Al allay is presented under 3.5% NaCl solution from one day, one week and one month under room temperature and stress ratio R= -1. The results show that the shot peening has strong effect on the fatigue strength at 107 cycles for corroded specimens. In case of shot peening ,only 17.5% loss in fatigue strength even after submerging for one week compared with 60% of the fatigue strength was reduced in case of un shotted specimen . But for one month pre – corroded specimens, the fatigue strength was reduced by 64% in corrosion environment while shot peening improved the above reduction to be about 44%.

Environmenatal factors such as climate change, gradual decrease in water resources and threatened habitants prompted the need to monitor our environment and implement better policies to protect it, thus monitoring soil pF (potential factor) values become increasingly important for environmental monitoring. The commonly available instrument(tensiometer) do not measure the range of available moisture in all soil types rather measures soil water suction. The need to measure the range of available moisture in all soil types with accuracy led to the modification of tensiometer for satisfactory laboratory results. Due to the shortcomings associated with tensiometer readings, the pressure membrane apparatus is an important instrument for optimizing irrigation and erosion prediction models.This pressure membrane with extractor has two main components:a porous plate with air entry pressure and a sealed pressure cell. The soil from which pF value was to be determined was placed in a chamber in which the pressure increased above atmospheric pressure. The side of the chamber which supports the soil consists of a pressure relief valve supported on a pressure hose. This is to ensure that the extractor chamber was not over-pressurized. The soil water potential with the corresponding mositure contents of four soil samples: A (clay soil), B(loamy soil), C (sandy soil) and D (silt) obtained from different locations were determined using pressure membrane apparatus. At a potential of 104hPa, samples A,B,C,D showed moisture content of 0.05,0.25,0.30, and 0.45cm3/cm3respectively. From the obtained results, at potentail close to zero, sandy soil is close to saturation and moisture held in the soil, primarily by capillary forces. From the laboratory analysis, moisture content decreases with high moisture cohesion.

The reduction of fix and variable costs has significant impacts on proper machinery management. To measure the effects of new machinery management on fuel and oil consumption, a study was conducted using empirical data on eight Massey Ferguson 399 model agricultural tractors at Amir-Kabir agro-industry, Iran in 2011. The performance of Nano?-Diamond additive oil was compared with conventional oils. Results were shown that naturally low coefficient of friction combined with excellent chemical inertness made these additives very attractive in a wide range of applications in engine oils. Also, results shown : 21% and 25% reduction in fuel and oil consumption, respectively where Nano?-Daimond additives was applied in oil and consequently a reduction of pollution was measured on engine exhausts. The use of Nano?-Daimond oil shown a better performance for the reduction of fuel and oil on tractor engines’ costs by 14% where compared to the conventional oil.?

A numerical study is presented on the effects of chemical reaction and magnetic field on the unsteady free convection flow, heat and mass transfer characteristics in a viscous, incompressible and electrically conducting fluid past an exponentially accelerated vertical plate embedded in a porous medium by taking into account the heat due to viscous dissipation. The problem is governed by coupled non-linear partial differential equations. The dimensionless equations of the problem have been solved numerically by the implicit finite difference method of Crank – Nicolson’s type. The effects of governing parameters on the flow variables are discussed quantitatively with the aid of graphs for the flow field, temperature field, concentration field, skin-friction, Nusselt number and Sherwood number. It is found that under the influence of chemical reaction, the flow velocity as well as concentration distributions reduce, while the velocity reduces as porous medium increases. Viscous dissipation parameter leads to increase the temperature.

This paper reveals the mechanical and metallurgical properties of the dissimilar joints of AA2024 aluminium alloy and commercial grade copper alloy fabricated by diffusion bonding process. Three diffusion bonds with varying diffusion layer thickness were fabricated and study the effect of diffusion layer thickness on mechanical and metallurgical properties. Mechanical properties such as lap shear strength, bonding strength and hardness are evaluated, Metallurgical characteristics such as diffusion layers thickness, phases in diffusion layer, elemental composition of diffusion layers were analysed. From this investigation, it is found that the diffusion bond with a medium diffusion layer thickness (in between very minimum to very maximum) exhibits superior mechanical properties.

Higher quality and cost effective welds can be achieved by understanding the weld metal properties and influence of welding parameters. Submerged arc welding is preferred process for the higher productivity and better finishing of deposited metal. Welding input parameters have significant role in determining the quality of a weld joint. The joint quality can be assessed in terms of weld bead geometry and weld metal properties. Investigation has been made on influence of welding input parameters on weld bead geometry and metallurgical properties.

In this paper, we used Taguchi design to find an optimum condition for semi-solid Al-Si aluminum alloy fabricated by cooling slope plate method. In CS method, molten alloy was poured over an inclined cooling plate in order to make the semisolid slurry. The semisolid slurry ?owed and solidi?ed into a mold placed at the bottom end of the slope. In Taguchi’s design, it is well-known that high value of S/N ratio (Signal vs. Noise) is better. Consequently, manufacturing conditions were arranged as table of orthogonal array L9(34), and then pouring temperature and tilt angle of cooling plate factors were determined. From microstructural observations, grain size and shape factor were measured by image analyzer. The results of S/N ratios showed that the pouring temperature has the main effect on grain size and morphology of silicon phase of an Al-23%Si alloy cast by cooling slope plate method, since S/N ratio which is sensibility on surround environment was the highest. The optimum conditions were also identified.

The experiment was conducted at the fields of Agriculture College-University of Baghdad Al- Jadiriyah in 2015 in sandy loam soil to evaluate using locally Ultrasonic device for determining the tillage appearance for different primary tillage equipment. New Holland" tractor was used in this study. Two levels of soil moisture included 18-20% and 14-16% and primary tillage implements included: disc plow , chisel plow and sweep plow were used . Soil surface roughness, number of clods with diameter larger than 10 cm , disturbed soil volume, bulk density, total porosity were measured. Split plot design under randomized complete block design (RCBD) with three replicates was used. The results were showed that the best soil surface roughness was obtained at the second moisture level, and higher porosity 53.89 % at the first moisture level and there were no significant differences for levels moisture in both the number of clods with diameter larger than 10cm , disturbed soil volume and bulk density. Sweep plow superior in obtained less soil surface roughness , less number of clods with diameter large than 10cm 10.00 clod / m2 and higher porosity 53.94 % compared with chisel plow and disc plow. Higher disturbed soil volume obtained at the chisel plow 1193.00 m3 / hr, while no significant differences in bulk density attributed by plows types. Sweep plow with second moisture level was the superior in obtained less soil surface roughness and less number of clods with diameter large than 10cm 9.33 clod / m2, and sweep plow with first moisture level obtained less bulk density 1.17 mg / cm3 , higher porosity 55.33% While higher disturbed soil volume 1202.00 m3 / hr. obtained in chisel plow with first moisture level treatment

The present paper has focused on the development of an Alluminium metal matrix composite (AMMC) which posses good mechanical properties to meet the functional requirements as the materials of machine elements. The AMMC samples are prepared by mixing reinforcement materials like SiC, Al2O3, Al3C4 in different sizes and percentages with Alluminium base materials like Al6061, Al6063, Al7075 using stir casting furnace according to taguchi orthogonal array OA L9 for minimizing experimental cost. The properties (responses) like density, tensile strength, impact strength, and hardness are determined for the samples. These responses are studied and analyzed using fuzzy logic and the optimum combination of influential factors are identified. A new sample is prepared as per identified combination and tested for confirmation, and it is satisfactory.