Proportional and servo valves are used to control the velocity, or force of an actuator. In some cases, two or more parameters have to be controlled. For example, as a cylinder is extended, its velocity might be controlled. At the end of the cylinder's stroke, the servo system may be used to either position the cylinder or to control the exerted force on the work piece. In present study the dynamic performance of an electrohydraulic system, containing a proportional directional valve, has been investigated theoretically and verified experimentally. The electro-hydraulic system, under investigation, contains an electrohydraulic proportional valve which is used to control a hydraulic cylinder velocity under constant load. The electrohydraulic system consists of a hydraulic tank, a gear pump; a relief valve; a proportional directional valve; a hydraulic cylinder with vertical load; and connecting hoses. Experimental works have been carried out to measure the pump-relief valve characteristics and the pressure losses in the connecting hoses. These measured data have been curve fitted to simulate the characteristic of the pump-relief valve and the connecting hoses. A verified theoretical model of the directional proportional valve, which was previously presented and published in [Menshawy, T.M., "Investigation of Dynamic Behavior of an Electro-hydraulic Proportional System", M.Sc. Thesis, Military Technical College, Cairo, Egypt, 2006.], has been used here. The simulation model of the hydraulic cylinder with vertical load has been carried out. All these models have been introduced within the MATLAB-SIMULINK environment in order to obtain the theoretical simulation program of the electrohydraulic system operation. The model of the electrohydraulic proportional system has been validated experimentally and has been used to investigate the performance of the system when works under different operating conditions.

Prior methods for tracking multiple military objects include various optimal and suboptimal two-dimensional assignment algorithms which make nearest-neighbour measurement-to-track association. This method works reasonably well in case of small number of targets and high signal to noise ratio. Another method is to assign a weight for each measurement and use a weighted centroid of those measurements to update the track. This method of weighting the measurements is known as all-neighbour and overcomes the disadvantages of the nearest-neighbour data association. Unfortunately, the computational complexity of an optimal all-neighbour data association technique limits its practical realization using even the fastest computers available. For this reason, many different tracking techniques have been developed which sacrifice optimal performance for the sake of computational feasibility. This paper proposes a new computationally feasible measurement weighting method to the problem of multiple targets tracking in a noisy environment. Computer simulation results indicate that the proposed weighting method successfully tracks multiple targets with a lower computational complexity and a little prior knowledge.

Muzzle blast wave in small arms represents special problems for many applications. They may be attributed to supersonic flow of the discharged propellant gases from the barrel muzzle after the projectile departure. Herein, experimental investigation of controlled and uncontrolled blast wave has been carried out under different working and design parameters. Different silencer design theories were carried out, to control the blast wave in both subsonic and supersonic cases, which produced from automatic small arms. The pressure-time history of gases discharging from an automatic rifle 7.62 x 39-mm was measured for different mass of propellants. In addition, recoil force for the rifle without as well as with silencer and the projectile muzzle velocity has been measured. Results showed that, for different mass of propellants in ammunition and suitable design of silencer, the sounds could be reduced by about 90 percent. In addition, silencers reduced recoil energy by about 20 percent. Also, the silencer efficiency increases by decreasing blast wave pressure as well as mass of propellant of ammunition decreasing.