Mechanical Engineering

Field experiment conducted to measured Slippage, Effective field capacity, Field Efficiency, Soil Volume Disturbed and Specific Productivity Tillage in silt clay loam soil with depth 18 cm in Baghdad- Iraq. Split – split plot design under randomized complete block design with three replications using Least Significant Design 5 % was used. Three factor used in this experiment included Two types of plows included Chisel and Disk plows which represented main plot , Three Tires Inflation Pressure was second factor included 1.1 ,1.8 and 2.7 Bar, and Three forward speeds of the tillage was third factor included 2.35 , 4.25 and 6.50 km/hr. Result show chisel plow recorded best parameters performance.

The objective is to determine blend which gives less emission and good performance characteristics, comparing emissions and performance characteristics between blends and pure gasoline fuel at different speeds, different compression ratios and different loads and carry out the test on VCR engine at full throttle valve opening without modification and without knocking at, different gasoline-ethanol blends (E5,E10,E15) and pure gasoline, different compression ratios (8,9,10) and different speeds (1600,1700,1800 in rpm) where, performance characteristics are volumetric efficiency, brake power, brake thermal efficiency and emissions of CO, CO2, HC.

This paper outline is an experimental study to optimize process parameters of plasma arc cutting for stainless steel 420. Three process parameters were chosen these are cutting speed, cutting current and torch height. The experiments are conducted based on taguchi’s L9 OA. The objective of optimization is to attain minimum Ra and maximum MRR individually. Regression models for Ra and MRR are developed based on Regression analysis in Minitab 17 Software. The optimal settings is obtained for Ra and MRR by using Genetic algorithm optimization technique in MATLAB R2013a software.

One of the most challenging problems encountered by a fluidized-bed designer is assessing how changes in bed geometry and operating conditions affect the gasifier performance while scaling up to demonstration / commercial size. Typically, commercial gasifier designs are based on operating experience from small pilot plants. A cold model of a gasifier represents an inexpensive and convenient platform for conducting detailed hydrodynamic studies that would otherwise be impossible in the hostile high pressure and temperature environment of fluidized bed gasifier. A perspex three dimensional semicircular cold model test rig of ID 940mm which is hydro dynamically scale down model of a demonstration plant of 168 TPD pressurized fluidized bed gasification (PFBG) plant is established and hydro dynamic parameters viz Froude no., bubble rise velocity, and bubble diameter are presented which are used for further scale up. Besides performance of the gasification process involves knowledge of dynamics of two phases viz. solid (coal) and gaseous for scale-up of the gasifier. The measurement of mean residence time (MRT) and degree of axial mixing of solid phase is required for evaluation of PFBG .The paper presents the residence time distribution (RTD) studies carried out in a pilot scale hot model of PFBG of 200 mm dia and verified in a hydro dynamically similar cold model .The coal particles labeled by radio tracer Lanthanum -140 was used to measure RTD by collimated scintillating detectors located at ash extraction points at the bottom and gas outlet at the top of the gasifier .The measured RTD data of coal / ash particles were treated and normalized for arriving at the mean residence time (MRT). The treated RTD data were simulated using gamma distribution model and found that model predicated MRTs of cold and hot model tests were in good agreement. The paper suggest the parameters which assist to minimize the bypassing of the coal particles in the gasifier thus improving the carbon conversion efficiency and hence enable scale-up of the PFBG.

The prediction of long term mechanical properties of sandwich structures consisting of PU foam core and Vinyl Ester (VE) / Glass face sheet material under temperature, humidity and salt fog environment were performed by accelerated testing methodology based on the Time-Temperature superposition principle (TTSP). PU foam cored VE/ glass fibre reinforced sandwich structures with varied densities of PU foam were prepared and tested for degradation in flexurall properties at three different temperatures (30° C, 40° C, and 50° C) and RH 95% for a period of 120 days. The degradation in flexural properties such as Facing Bending Strength (FBS), Core Shear Strength (CSS) and compression properties (edgewise and flatwise strength) were studied. The master curves for FBS, CSS,ECS and FCS were constructed by using the test data obtained from the degradation studies at three different temperature conditions based on Time temperature super position principle and the acceleration factor has been determined. An effort has been made to develop methodologies for accelerated testing of sandwich structures for long term durability considering time, marine ambiance, temperature and humidity as major influencing parameters

Efficient energy conversion devices are the most important need of the hour looking at the global energy scenario. Catering to this need, better and more efficient designs are been put forward regularly. New and better methods of energy conversion are also been proposed. The use of Turbocharger in an engine is an example of the same. But the critical examination and of these devices is of utmost importance. Simulation is a tool that can reduce the efforts that need to be put in physically and can carry out virtual calculations and can respond the results too. There are various pre-programmed software that contain a variety of models that can be employed to study the parametric variation and carry out the simulation. This paper deals with study of three such turbulence models namely the k-epsilon, k-omega and the Shear Stress Transport model. A number of parameters will be considered and simulations will be carried out on all the three models with the view of determining the most suitable model among the three with the ability to provide optimum results for the study of a turbocharger turbine stator optimized for producer gas. The results will be obtained in the form of graphs and contour images which will be studied to determine the most suitable model for further use. Based on the results, suitable conclusion will be drawn and stated towards the end.

In recent years, the food industries experts have drawn their attention toward using high frequency ultrasound waves in producing processes. The main part of these equipments is the ultrasonic probe which called sonotrode. The performance of ultrasonic equipments depends on properly design of sonotrode shape. In this study, four methods were used to design the ultrasonic probes for use in food and chemical industries. Two types of probes, namely, step type and cylindrical type were considered and the related calculations for the both types of probes were performed based on the four design methods. For both of the cylindrical and step type probes, the length of the designed probe was equal to half of the ultrasonic wavelength. Modal analysis of the models were determined by the numerical simulation using finite element method (FEM) design procedures. The results showed that although the probe material does not affect vibration amplitude, it can affect stress distribution along the probe. In the cylindrical type probe, the maximum stress raised in the middle part of probe, whilst in the step type probe, regardless of design probe, the maximum stress was occurred in the surface variation location. Based on the results, to design a probe, it should be noted that the maximum created stress in the probe must not exceed the yield stress of the selected material.

The study focused on the modelling of a candle flame using CFD modelling technique. Governing equation which formed the basis of a CFD modelling using SolidWorks flow simulation was developed, and the simulation result was compared with an existing experimental result. Modelling results show that the heat flux is maximum at the wick base and minimum at a distance of 0.1m from the wick tip, where it maintains averagely a constant value of 55.23kW/m2. This implies that the heat flux generated by a typical candle is large enough to ignite secondary objects such as wood materials located even 100 mm above the wick of the candle as they are capable of auto-ignition at heat flux above 40kW/m2. However, nearby objects that are not directly over the candle base can also be ignited, but must be located much closer for ignition to occur.

Overheating is the major problem ofhermetic compressor due to extra amount of heat added from the motor windings to the shell. It reduces the mass flow rate of the system which results in reduced compressor volumetric efficiency and extremely high discharge temperature. The refrigerant injection is a technique to improve the system performance. This paper reviews the major research on refrigerant injection techniques in detail. The refrigerant injection technique divided into two categories, first is vapor injection and another is liquid injection. Flash tank and internal heat exchanger are two cycles for refrigerant injection. These two cycles are discussed in detail.

Piezoelectric materials appealing for use in smart structures as sensors and actuators instantaneously transform mechanical energy to electrical energy and contrariwise. They remember configurations and guarantee them when subject to stimulus, have superb electromechanical coupling characteristics and outstanding frequency response .Innumerous utilization of smart structures technology to diverse physical systems have progressed to actively control shape, aeroelastic stability, noise, damping, vibration and stress distribution. In this article the research activities of piezoelectric materials for smart structures is grouped into characterization, formulation, analysis, applications & debonding in aid in future research activities in any of the grouped class.