Numerical modeling of internal nozzle flow can be regarded as an essential investigation in the field of gasoline direct injection system of combustion engines since it is directly connected with fuel spray atomization and subsequently efficiency of exhaust gas emission. Internal nozzle flow can be changed and formed according to several PARAMETERs such as; system pressure, chosen fuel type, the orientation of spray holes according to injector axis, conicity of spray holes and distribution of spray holes on valve-seat, etc. The changes in these PARAMETERs also affect the formation of cavitation inside of whole domain, spray angle and create wall-wetting on the spray hole surfaces. The present work investigates the PARAMETER and DESIGN analysis in the valve-seat region of direct gasoline injection (GDI) injector using Computational Fluid Dynamics (CFD) and DESIGN of Experiments (DOE). CFD is employed to study the behaviors of internal flow inside the valve-seat region according to several DESIGN PARAMETERs, whereas a mixed-level factorial DESIGN is used to test the significance of the effects on the response variables. In conclusion, the effects of the most significant factors on response PARAMETERs as amount of vapor formation, spray (Tau) angle, and pre-hole wall wetting are determined for further efficient DESIGN.

Response surface is an e ective method for robust PARAMETER DESIGN. Previous response surface methodologies assume that independent variables are measured without errors. However, this assumption might be violated due to the low capability of the measurement system. The present study employs the response surface method for robust PARAMETER DESIGN with measurement errors in variables. In addition, an unbiased estimator is presented in the presence of some measurement errors and an optimal setting which is determined to minimize the expected quadratic loss. An example is then illustrated to verify the e ectiveness of the proposed approach. The results showed that the proposed method could achieve better operating conditions, despite measurement errors, than the conventional method.

Measurement of the air PARAMETERs above the Earth's surface has many research and operational applications including weather forecast. A radiosonde system is carried by a balloon up to the top of the troposphere or above it and obtains various information such as pressure, humidity, temperature, location, velocity, and wind direction at different altitudes from the Earth's surface during its climb. Then, the measured data are transmitted to the ground station using a radio transmitter. In this paper, the system DESIGN and fabrication and testing steps of a radiosonde operating at 400. 6 MHz with the ground receiver and the associated antenna are described in detail. The aim of the project is to build a local radiosonde system to meet the requirements of the meteorological organization. Although the price of this system is very low compared to its foreign equivalent, its measured performance and stability under severe temperature changes are in good agreement with those of foreign counterparts.

Poly (vinyl chloride) (PVC) /acrylonitrile butadiene rubber (NBR) /organoclay (Cloisite 30B) nanocomposites have been prepared via direct melt mixing in an internal mixer. The application of Taguchi method for reducing cost and improving properties in NBR/PVC nanocomposites is reported. Processing PARAMETERs such as temperature, rotor speed and mixing time have been verified in relation to the mechanical properties of nanocomposites. The relative magnitude of each specific factor, interactions between all possible combinations of two factors and the performance estimation at any arbitary condition are also determinded. The experimental data are compared with the estimated data obtained by Taguchi method to examine the accurancy of the predicted values. The structures of nanocomposites have been characterized by X-ray diffraction, scanning electron microscopy and small amplitude oscillatory shear rheometry. X-Ray diffraction results show that the interlayer spacing is significantly influenced by processing conditions. The study of linear viscoelastic properties shows that storage modulus (G') and complex viscosity, |h*|, are very sensitive to the microstructure of the nanocomposite. Dynamical mechanical analysis of NBR/PVC nanocomposite samples has been investigated as well. The results confirm that the Taguchi method is a useful tool for estimating the mechanical properties of NBR/PVC nanocomposites.