The aim of the research is to investigate the ability of improving the vehicle safety, performance, and reduce operating coast by using nitrogen inflated tires. In this study, three cases were proposed to study the effect of Nitrogen Tires on Car Vibration and Fuel Consumption. The study was conducted according to the three cases; filling the tires with air only, 50% air and 50% nitrogen and nitrogen only. When adding 50% of the nitrogen with the air to the tires, it reduced the vibration velocity to 10% at 60 km/h, 6.6%at 80 km/h and 7.5% at 100 km/h. Also when filling tires with nitrogen, it reduced the vibration velocity to 28.4% at 60 km/h, 23.6% at 80 km/h and 22.7% at 100 km/h. The decrease in fuel consumption for the addition of 50% of the nitrogen was 4.05% while the addition of nitrogen by 100% was 6.1%.

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Experimental and computational investigations have studied the heat transfer, friction factor, and enhancement of heat transfer in a horizontal tube equipped with rectangular cut ring inserts and different diameter ratios (D/d) and pitch-to-tube diameter ratios (p/d t ). In the present study, air having a Reynolds no. range of 6700-20,100 was used as a working fluid. Three diameter ratios (D/d) were considered experimentally and numerically as 1.2, 1.25, and 1.3, and the pitch-totube diameter ratio (p/d t ) was (1, 0.625, and 0.5). Air was forced as working fluid through the tube and a uniform heat flux of 2000, 3500, and 5000 W/m 2 was applied through the tube's exterior surface. On the basis of the turbulence model k-ɛ with various parameters, three-dimensional numerical simulations using the ANSYS Fluent software 17.2 were investigated. Under the same working conditions, the results manifested a higher heat transfer rate and friction factor as compared to the plain tube. The results evinced that the Nusselt number for a horizontal tube equipped with rectangular cut ring inserts having various pitch ratios and diameter ratios is discovered to be higher than that for the plain tube. With the increased ring spacing, the overall improvement in heat transfer occurred. And, with a rise in Re, the total

The nature of natural fibers is porous, which is useful feature for sound absorption. These types of materials (natural) are less ecofriendly and ecofriendly. This study deal with the effect of using natural composite material as sound insulation, many types of natural materials with fiber glass had been used in this study, i.e. cotton, wool, fronds and vegetarian fibers with different thicknesses. The study consist of built attest rig to measure the different frequencies and sound waves experimentally to calculate the transmission losses and coefficient of transmission losses that are dialing from function generator use sound pressure level. The best results of transmission losses recorded for the composite materials (Polyester +Random + wool) and (polyester + fiber glass + cotton) in three thickness 6mm, 8mm and 10mm. From other side, the best results of absorption of noise at different frequencies recorded for (polyester + fiber glass + cotton) and (Epoxy + fiber glass + plan fronds) in three thicknesses.

Natural convection from flat plate built in variable height duct was investigated experimentally. With air as the working liquid the impact of variable height duct on the heat transmission of the flat panel were studied. Duct was with Square section of (300×300) mm2 and the elevation of the duct H was various asl00, 200 and 300 mm. square flat plate (300×300) mm2 which heated surface facing upwards, was built in the bottom of the duct and exposed to different input power which represent a heat flux of (423, 660 and 830 W/m2. The experimental results showed that the variable height duct deteriorate the heat transmission. heat transmission of the flat panel built in a variable height duct become lower than those do not have a channel and heat transmission are significantly reduced in the circumference of the duct. at circumference of variable height duct, heat transmission for flat board become 27% smaller than heat transfer for flat panel that do not have a duct owing to that the perpendicular duct hinders airflow from the top of the perpendicular duct this causes decrease of heat transmission.