Iraqi journal of mechanical and material engineering

An experimental investigation was conducted to study single-phase fluid flow and heat transfer in a copper micro channel. To investigate the effect of artificial cavities on fluid flow and single phase heat transfer in micro channel heat sink, two model of straight micro channel recognized as two models (model -1and model -2) were designed and manufactured ,where model-1 have smooth bottom surface while Model-2 have 47 artificial cavities distributed uniformly at the bottom surface along the micro channel length. The two models having the same nominal dimension of 300μm height and 300μm depth while the real dimension value are 367 μm for width and 296 μm for depth .De-ionized water was used as the working fluids. Experimental test was conducted at 30ᵒC inlet temperature with Reynolds numbers range from 700 to 2200 covering laminar flow conditions. The experiments were conducted with horizontal micro channel under both adiabatic (for friction factor calculation) and diabatic (for Nusselt number calculation) conditions. The results indicated that the experimental Darcy friction factor can be predicted well with conventional scale fanning friction factor correlations for developing flow in laminar region by shah and London (1978) correlation for two models. Also, the experimental Nusselt number Agree well with each correlation of shah and London (1978) and Mirmanto correlation in laminar region.

An experimental investigation involves the effect of the turning hollow-cylinder within a solar water distillation on the output of distillate water. This study is to be conducted in order to validate the optimum productivity of purification water by turning hollow-cylinder. The experiments were carried out in Kirkuk city, Iraq, 2018.
Experimental results demonstrated that a basin water height is (1 cm) gives the better productivity of (1225 ml/ m2.day) for the conventional solar water distillation, and (2 cm) basin water height for the modification solar water distillation gives the optimum productivity which is (3540 ml/m2.day) which represent an increase of 188% when compared with the productivity of the conventional solar water distillation. 0.5 rpm and 1rpm are the optimum rpm for the hollow cylinder for the modification solar water distillation without and with flat plate solar water collector. The maximum percentage of productivity obtained from the modification solar water distillation which connected to a solar water heater with automatically varying speed according to the solar radiation intensity (Auto turning + Collector) gives more than (310%) enhancement. The estimated cost of one litre distillate water output for modification and conventional solar water distilleries were 136 ID and 175 ID respectively.

The aim of this research is to determine a simulation of an electric control unit (ECU) for direct injection compression ignition combustion engine, in order to improve an engine performance and reduced fuel consumption. The simulation comprises thermodynamic model for determining engine parameters according to Spray Penetration Mixing Length, and imposes in Matlab and Simulink. This model allows closed loop control interferences with Arduino MEGA-2560 to manage amount of injected fuel and start of injection that, could be lead to obtain the optimum thermodynamic energy. The results of thermodynamic model show that, the engine parameters can be related linearly, and matching the other published researches on the same conditions and specifications. The results of (ECU) show synchronization between desired and output signals and appear more accuracy when compared with other methods.

Experimental ּּinvestigation of performance and emission of conventional a four-stroke, single-cylinder direct injection (DI) diesel engine at variable engine speed range from (1500 to 3000 rpm), carried out at steady-state tests conditions with diesel fuel and biodiesel which is produced from sun flower oil mixed with the higher alcohol. The blends effects on the performance and emission for the blended fuels measured and compared. 10% and 15% of Pentanol, Octanol added to the biodiesel blended with diesel for various test conditions. The experimental results showed an approximately 2–9% increase in the brake-specific fuel consumption (BSFC) for the prepared blends of pentanol and octanol due to the lower heating value (LHV), with higher brake thermal efficiency compared to diesel fuel. With expressively reduction of (9.8-21% vol.) in carbon monoxide (CO), and total unburned hydrocarbons (THCs) of (65-78.3% ppm), and nitric oxides (NOx) (44.4–52.9% ppm). The combustion analyses showed that the addition of biodiesel to conventional diesel fuel decreased the ignition delay and reduced the properties. These results indicated that biodiesel and higher alcohol could be used without any engine modifications as an alternative and environmentally friendly fuel. "

The present study represents an attempt to improve wet wear resistance through electroplating coating samples of low carbon steel. Minitab 18 program was used to precipitate a composite coating layer (Ni-SiC) because it is used in many industrial applications that require wear resistance. The samples were coated using different variables as inputs: SiC concentration, stirring velocity (r.p.m) and deposition time (min) for three levels using central composite design for design laboratory experiments. The factors of coating thickness (C.T), surface roughness (Ra) and Brinell hardness (HB) were adopted as outputs response and a complete analysis of variances (ANOVA) at constants significances levels of %5, was done to fully identify the most significant parameters. The surface response methodology (RSM) was used to give an optimal model with the best optimum properties such as Brinell hardness, surface roughness and coating thickness to improve wet wear resistance of low carbon steel samples. The results showed respectively that the SiC wt.% was the most effective on all the outputs response then deposition time (min) and stirring velocity (r.p.m).

Spin coating is used in various industrial and engineering applications, inducing the producing of thin films within nano-scale boundaries. In industrial processes, different substrates can be subjected to spin coatings, for example, micro microfilms, etc. In this research, Titanium tetra-isoperopoxide (TTIP) is used in the preparing of composite coatings by sol-gel spin method. The structure and chemical compositions of the composite coatings are studied using X-ray, SEM and EDS methods. The XRD pattern clearly shows the additions of 2% and 4% ZrO2 and their effects on the morphology and crystalline structure of titanium oxide, in addition; increasing the additives of ZrO2 in TiO2 films improves the intensity of diffraction peaks. The optical photographs show the microstructure of TiO2 doped 2% and 4% ZrO2 crystallization beads film measured to be 100.81 μm and TiO2 doped with (2 and 4% ZrO2) films are approximately 122.8813 μm in thickness. The SEM results of pure sol-gel TiO2 are relatively smooth, almost uniform dispersion of ZrO2 particles occurs in the matrix. The EDX results show the presence of the Ti and high amounts of Zr in the structure of the matrix. Coating hardness measurements exceed 70% with doped TiO2 and it increases with increasing the amount of zirconia.

Silicone rubber (SIR) is superior to natural rubbers due to having special features like high chemical stability, heat, abrasion and ozone resistance. Global markets show huge attention to produce and use silicone rubber in many applications such as aerospace, automobile, construction, electric insulators and medical industries. Although silicone rubber is hugely utilized in high voltage insulators, it shows low properties such as mechanical properties. Therefore, fillers are added to silicone rubber in order to reducing cost and improving the surface hydrophobicity, thermal and/or electrical conductivity, thermal and/or electric insulation and mechanical properties. This paper reviews on structure, types, general properties, manufacturing methods, applications of SIR, fillers and silicone rubber nanocomposites. It is focused on the popular micro/nanoparticles for dielectric applications. Organic montmorillonite (OMMT) represents one of the most important fillers that are used for dielectric applications. OMMT is added to SIR to improve the cost and electric and thermal insulation and mechanical properties. Tensile properties of SIR/OMMT nanocomposites increased with increasing the content of OMMT. SIR/OMMT nanocomposites with smaller OMMT size showed the highest compression strength and the lowest tear strength. SIR/OMMT Nanocomposites with high content of OMMT displayed greater thermal stabilities, flame retardant properties, dielectric permittivity and dielectric loss.