A stepped short tube orifice has been proposed as a replacement for the expansion mechanism in a residential refrigerator that runs on R-290. The present work is primarily concerned with the impacts of stepped short tube orifices on system characteristics such as net refrigeration effect, compressor effort, pull down time, and coefficient of performance. A stepped short tube orifice is made up of two short tube orifices linked serially and having varying sizes. It is used as an extension to the capillary tube in the refrigeration system. A stepped short tube orifice is built and fitted to a home refrigerator in this experiment. The experiments must be done on a home refrigerator equipped with a stepped short tube orifice, R-290 refrigerant, and a 0.5% weight SiO2 nanoparticle. Following the completion of all trials, the effects of the stepwise short tube orifice on a residential refrigerator were studied using comparison charts. The results indicate that the performance of the home refrigerator with stepped short tube orifice and SiO2 nano particle inclusion was much better than the domestic refrigerator without stepped short tube orifice

The free convection phenomenon from a heated square cylinder submerged in Bingham Plastic fluids is numerically investigated. The governing equations are solved for a wide range of physical dimensionless parameters, such as Rayleigh number (102 ? Ra ? 105), Prandtl number (10 ? Pr ? 100) and Bingham number (0 ? Bn ? 107). The heat transfer characteristics are investigated in terms of local Nusselt number distribution over the surface of the cylinder surface average Nusselt number. Streamlines, isothermal contours, yielded and unyielded regions are visualized in detail.

A Multilevel inverter is a very important tool for PV Array and Electric Vehicle etc. in Modern ERA Because the non-renewable energy is important for our future. The non-renewable energy is reducing the pollution and carbon content in the environment and also reducing the fossil fuel requirement for transportation and producing electricity. The multilevel inverter can provide higher level of sinusoidal output with less total harmonic distortion with the help of pulse width modulation. Different type of Pulse width modulation like POD APOD etc. can be implemented. 3 level inverters with the use of Phase Opposition Disposition pulse width modulation (POD-PWM) technique with 2 carrier signal with inverter with 4 IGBT switches is proposed. All the carrier signals are above X-axis are out of phase with the below signal by 180?. Total harmonic distortion of load voltage is 35.45 % and load current is 35.51 % obtained. This inverter can be use with solar photo voltaic cell. By the use of this inverter the higher-level output and less harmonic distortion output obtained. By the use of this output the electrical equipment is in very safe condition.

A Multilevel inverter is a very important tool for PV Array and Electric Vehicle etc. in Modern ERA Because the non-renewable energy is important for our future. The non-renewable energy is reducing the pollution and carbon content in the environment and also reducing the fossil fuel requirement for transportation and producing electricity. The multilevel inverter can provide higher level of sinusoidal output with less total harmonic distortion with the help of pulse width modulation. Different type of Pulse width modulation like POD APOD etc. can be implemented. 17 level inverters with the use of Phase Opposition Disposition pulse width modulation (POD-PWM) technique with 16 carrier signals with cascaded inverter with 16 IGBT switches is proposed. All the carrier signals are above X-axis are out of phase with the below signal by 180?. Total harmonic distortion of load voltage is 7.26% and load current is 3.09% obtained. This inverter can be use with solar photo voltaic cell. By the use of this inverter the higher-level output and less harmonic distortion output obtained. By the use of this output the electrical equipment is in very safe condition.

The elemental composition and trace elements determination of limestone deposits in Ikpeshi, Edo State is done through qualitative analysis of the limestone, and it was aimed at determination of the major and trace elements present in the limestone from the study area. Five limestone samples were collected from the study area for qualitative analysis using X-ray fluorescence spectrometer. The result shows that the major elemental composition of the limestone in the study area is Ca (90.59%), with Si (3.33%), Al (0.92%) and Mg (1.58%) and the minor elements are S (0.66%), Sn (0.53 %), Sb (0.52 %), K (0.49 %), P (0.37%) and Mo (0.29 %). The trace elements present in the limestone are V (0.0017 %), Mn (0.0015 %), Co (0.0033 %), Ni (0.0194 %), Cu (0.0151 %), Zn (0.03 %), As (0.0005 %), W (0.0131 %), Au (0.0178 %), Ag (0.0009 %), Rb (0.0031 %), Nb (0.0016 %). The chemical relationship for purity determination between Ca/Mg ratio in the limestone from the study area is 98.40, while the Mg/Ca ratio is 0.01 and this ratios falls into the pure limestone class which revealed that the limestone in the study area is a pure limestone.