A new technique is presented by which lateral outflows of material , from an oblique impact collision between wax projectile and a rigid surface , are collected to form a high speed single jet. This jet has been shown to be capable of producing cavities in semi-infinite target of wax in a manner similar to that produced in a hypervelocity impact situation. The produced jet capability of penetration is found to be maximum at higher velocities of impact , lower values of standoff and with projectiles having angle of obliquity in the range (â=20-25o). A preliminary theoretical model is also presented in an attempt to describe the process of jet creation and jet characteristics. The present technique is proved to be promising in simulating penetration of semi-infinite targets by the impact of high speed jet .
The reducing of heat gain through the outer walls of the buildings in summer will contribute in reducing the air conditioning costs. This is one of the best features of design requirements nowadays. To achieve this, the phase change materials (PCM) can be used as an embedded material in the walls to reduce heat transfer. The paraffin wax is one of the common materials used as a PCM in the building walls. The paraffin wax is used in this study with (20%) volume percentage in the external layer of the treated wall. In the present work, the treated wall (with embedded wax in the wall) and non-treated walls have been experimentally investigated. Two Iraqi wall models were employed to run the experiments, whereby these models were exposed to an external heat source using (1000 W) projector for each model. The temperatures were recorded at different locations in the walls during the charging and discharging periods. The results showed that the temperature of the internal surface for the treated wall was lower than that of the non-treated wall at the end of the discharging period (6 hr) where the temperature difference between the treated and non-treated walls was reached (1.6℃).
This paper describes a numerical method for calculating the temperature distribution and latent heat storage (LHS) in the treated wall (TW) and non-treated wall (NTW). The developed method was assumed that the outer cement layer (Iraqi wall) enveloping the external wall of building and houses are contains paraffin wax as a phase change material (PCM). (25%) is the volume percentage of paraffin wax is mixed with cement which forming a treated layer. A comparison results between the (TW) and (NTW) has been done. The paper presents a simple calculation of case study for air-conditioning in two walls type of residential building. The outer solar air temperatures as function of day time are considered for a hot day in summer (July) for Baghdad city. The aim of this paper was to obtain physical validation of the numerical results produced from using developed FORTRAN program. This validation was obtained through a comparison of numerical solution of two different wall compositions exposed to the same external and internal load conditions. The calculations on transient heat transmissions across different walls were conducted. It was found that when using the (TW) with (PCM) produces lower surface and heat flux towards the cooling space with respect to (NTW).
The Cooper-Harper rating of aircraft handling qualities has been adopted as a standard for measuring the performance of aircraft. In the present work, the tail plane design for satisfying longitudinal handling qualities has been investigated with different tail design for two flight conditions based on the Shomber and Gertsen method. Tail plane design is considered as the tail/wing area ratio. Parameters most affecting on the aircraft stability derivative is the tail/wing area ratio. The longitudinal handling qualities criteria were introduced in the mathematical contributions of stability derivative. This design technique has been applied to the Paris Jet; MS 760 Morane-Sualnier aircraft. The results show that when the tail/wing area ratio increases the aircraft stability derivative increases, the damping ratio and the natural frequency increases and the aircraft stability is improved. Three regions of flight conditions had been presented which are satisfactory, acceptable and unacceptable. The optimum tail/wing area ratio satisfying the longitudinal handling qualities and stability is (0.025KeywordsLongitudinal Handling---Stability---Tail Design