Al-Qadisiyah Journal for Engineering Sciences

The city of Gaza is considered as one of the oldest cities in history with its roots extends to three thousand years BC. The City was a cradle for many civilizations including Canaanite to the Byzantine and Christian periods and then to the Islamic era and subsequent periods, i.e. Mamluks and Ottoman rule. All these periods have affected its development and left us a unique legacy and cultural heritage represented by a lot of historical buildings. In order to preserve this heritage from destruction, the researcher aims to develop an approach to adaptive reuse historical buildings in the city of Gaza as much as possible by adopting a scientific research method relied on the description and analysis based on five main themes. The first point addressed some concepts related to the adaptive reuse of historical buildings in terms of the principles and goals. The second section attempted to shed light on Gaza City and its urban heritage and the most important historic buildings. The third part presented a proposed approach for adaptive reuse of building, which includes three phases: preparation of historical studies, on site survey to assess the current status of the building and the technical studies phase. The fourth issue handled the analytical study of Hammam Alsamra in the old city of Gaza as a case study. The last section referred to the most important findings and recommendations concerning the aim of the study.

This study is attempt to design development model for architectural education and it's about the process of development of architectural engineering departments in Iraq to improvement performance to arrive appropriate outcomes for work market and planning of development , in the other word to implement first step to quality assurance. This study not for critique departments of architectural engineering but it is try to design a system for development can be defined as a yardstick to evolution of development process designed according to new design methods and quality assurance programs in Arabic area and USA standard for architectural education . This system consist of three rings : First ring : management sides . Second ring : the scientific sides of architectural profession. Third ring : the applied sides for method of the development.

In the present study, the effect of the stress ratio change on the threshold of the fatigue cracks for an aluminum alloy have been researched. This aluminum alloy was taken from a blade of Russian MI25 helicopter. A specimen of MI25 blade has been cut into testing specimens of standard dimensions; the stress intensity factor as a basic variable has been calculate and used by making an initial crack in the test specimens.
The test have been conducted for five different stress ratio : ( R = - 1 , 0.0 , 0.1 , 0.3 , 0.5 ) : Several tested have been done to study the effect of these change on the threshold of fatigue crack result obtained in this research were compared to some well knows previous scientific theories and research in this field . At each stress ratio ( R ) , several specimens have been used to obtain the threshold stress intensity factor for that value of ( R ) . From the results obtained , it is clear that the value of the threshold stress intensity factor range (ΔK) decreases as the stress ratio increases. Whereas ; at a negative stress ratio: (ΔK) increase for threshold fatigue crack .

Nondestructive tests (NDT) are considered one of the methods of evaluation and quality control of concrete. In addition, Nondestructive testing give, good indications about strength and durability of concrete samples and structural members. There are many studies about Nondestructive tests for concrete NSC &HSC. So the fundamental aim of study is to construct a mathematical model to predict compressive strength of two types of concrete (Normal concrete and self compacting concrete ) exposed to high temperatures from Nondestructive testing ,by using (rebound number &ultrasonic pulse velocity). Where mathematical models proposed for concrete normal conditions with previous studies, do not give a true picture of the nature of concrete exposed to high temperature. The study included the preparation of three mathematical models for each type of concrete, two of which are based method of Multiple Linear Regression Analysis with a different number of independent variables supported model, while the third, it depends on the construct of a model of Non - Linear Regression Analysis using the exponentional equation .
The statistical models for normal concrete was high reliability, and owns two of them on two variables only were to hammer Schmidt test , ultrasonic pulse velocity test , and be more practical than the third model, which depends on several variables, where he finds it difficult in most cases Empirical lack of information application . The same result was reached to models for self compacting concrete with a different rate of reliability for both types of concrete for statistical indicators of each model.

Recycling of waste material is a recent technique aims to change the waste material into new products to reduce the pollution and detrimental effect on the environment and reduce the demand of new fresh natural sources. Plastic bags and Recycled Concrete Aggregate (RCA) are samples of these waste materials can be re-used in road construction. Over one million bags are used every minute worldwide, whereas, aggregate is consist of about 95% of asphalt mixture and can be obtained as RCA from demolished infrastructure. This paper presents laboratory tests results of using waste plastic and RCA in production of asphalt mixture. Since the cement past attached to RCA particles contribute to lower their density and increase the porosity, the waste plastic are used to enhance the engineering properties of asphalt mixture and consume these large amount of waste material. The results showed that Waste Plastic Modified Bitumen (WPMB) mix containing 100% RCA produces higher Marshall Stability, higher retained stability and higher indirect tensile strength compared with conventional mix. The percents of the increase were 10% for Marshall Stability, 7% for Marshall retained stability and 9% for higher indirect tensile

Dynamic analysis of parallel robotic mechanisms plays a vital role in the design and control of such robotic mechanisms. To simplify the dynamic analysis formulation, many researches had been done assuming the robotic mechanism joints as ideal joints (without friction). This paper represents a novel mathematical model for evaluation of friction forces, torques acting in the spherical, prismatic joints of parallel robotic mechanism and their effect on the dynamic formulation of any parallel robotic mechanism.
The aim of this paper is to obtain a new mathematical formulation for evaluation of the dynamic analysis in non – ideal robotic mechanism.
The results show that the friction forces and torques acting on the robotic mechanism joints have actual effects on the actuators to implement the same tasks. The actuators forces shall be increased about ten percentages than the power of the actuators in case of ideal robotic joints

In this work, a two-dimensional numerical model has been developed to study the thermal performance of a cylindrical heat pipe utilizing nanofluids. Al2O3-water based is considered as the working fluid. The numerical model represented as steady-state incompressible flow. The governing equations in cylindrical coordinates have been solved in vapor region, wick structure and wall region, using finite deference with forward-backward upwind scheme. A substantial change in the heat pipe liquid pressure drop, temperature difference, maximum heat transfer limit, capillary pressure and thermal resistance is observed when using a nanofluid. The nanoparticles within the liquid enhance the thermal performance of the heat pipe by reducing the thermal resistance and temperature difference by 0.168 K/W and 5.06 K respectively. While increasing the maximum heat load and the capillary pressure by 96 W and 192.46 Pa respectively. All these results at input heat of 30 W and nanoparticles concentration of 5 Vol. %.The results of wall temperature distribution for the heat pipe have been compared with the previous study for the same problem and a good agreement has been achieved.

Aluminum alloys are very important in many industrial applications because of their lights weight and good mechanical properties. There is a great need to recycle the metals and alloys used in the metallurgical industry and various engineering applications, particularly aluminum alloys due to
their low melting point and usefulness. In this work, the effect of copper wires addition with different percent on the microstructure and mechanical properties of Al-Si alloy (piston part as a scrape) were studied. Tensile test, hardness, microstructure SEM and XRD were conducted .The results showed that the addition of copper to the alloy (Al-12wt%Si) have improved its mechanical properties (tensile strength, yield strength and hardness) also changed microstructure of Al-Si alloy as compared with the base alloy.

A new implementation for the volume of fluid model with finite volume method is applied to simulate two-phase flow involving nano-particles. The model is used to investigate the laminar flow utilizing nanofluids in a lid-driven cavity. The fluid in the cavity is a water-based nanofluid containing Cu, CuO or Al2O3 nano-particles. The effects of adding extra phase (solid phase) and solid volume fraction for different nanofluids on hydrodynamic characteristics are investigated. The effective density and viscosity of nano-particles are calculated by Chon and Brinkman models, respectively. The CFD model is validated for laminar flow and the results showed good agreement with available numerical data. Then the model is tested for liquid and nano-particles where the results indicate that the effects of solid volume fraction approximately depend strongly on the effective density sequentially for Al2O3, CuO and Cu. In addition the effective viscosity has less effect on the flow field.