KUFA JOURNAL OF ENGINEERING

Wireless Networks became very important in this latest decade and especially Wi-Max system because of high bit rate, handover flexibility and longer distance of mobility. Signal strength and coverage is one of the challenges for this systems which leads to affect directly on Quality of Service (QoS), this paper is an attempt to design and study of Wi-Max network for a certain coverage area, testing the coverage of the signal for the area that can hold the sufficient amount of data with less latency has been studied depending upon the Wi-Max advanced specification and data stream behavior benefit’s, some Wi-Max parameters like coverage, quality of service, data rate are optimized, the study and design has been done using OPNET modeler used in the a simulation of the certain coverage area, in this paper the new campus of university of Salahaddin has been used on supposed area of about 4 X4 km. The results show a perfect bit rate as a bit stream for the global characteristics in which is sufficient to the students and teachers of the university in addition of providing the mobility by high performance. It is needed to design a wireless computer network to Salahaddin University to improve mobility and to let the teachers and students to stay connected at any time in any university location Especially with the nowadays learning techniques and requirements which needs both teacher and students to be online with each other especially like E-learning and online remount learning especially with the COVID-19 university campus blocking. Therefore, it is needed to cover overall area of the university campus and with additional coverage that exceed the university boundaries to improve the reliability of the hall network and to insure the required coverage area. To do that is very efficient to design an advanced computer network like Wi-Max with the most powerful and advanced hardware capabilities to full-fit the teachers and students requirement of fast net browsing and download in addition in e-learning bases it is very regular to use video conferencing or video streaming which normally needs a very fast network data transfer

Tube drawing are one of the most important forming processes manufacturing whole board. This process suffers from many problems regarding the deformation behavior of the tube material, as there is no control on the inner radius, i.e. wall thickening and failure at the end. This research involved implementing analytical and numerical simulation to investigate the ability of the tube to resist the failure under applied forces. The mathematical analysis was performed using Tresca yield criterion and the basis of force equilibrium to a representative element in the deformation zone, as it being drawn into the die under quasi-static equilibrium. Explicit dynamic analysis to the tube drawing process was performed using ANSYS 19.2 Workbench program. The analytical solution was used to validate the finite element results obtained from ANSYS program. Two types of material used in this analysis. The die material is made by 304 stainless steel. However, AL2024T351 was selected as tube material. The developed longitudinal stress and the thickness strain drawing process of the tube through conical die are studied. Investigated parameters that can affect the deformation behavior are taken into account. Such as, the die semi-angle (

One of the difficulties of using algae produces of biofuels the development of an active and economically feasible process for oil extraction from these unicellular algae. Algae have a high fat content. In this study two types of algae were used, Fucus vesiculosus and Cladophora glomerata moss algae. Where these algae are collected from swamps and marine waters and left under sunlight to dry for a period of three days. A comparative study was conducted to extract fats from algae using Soxhlet where organic solvents were used in the separation process such as methanol and ethyl acetate. Methanol is used more often because it is cheap and has chemical and physical characteristic. We use the ethyl acetate to prove that not good for extraction. The extraction processes by using organic solvents in the Soxhlet device have shown promising results. Different ratios of solvent to algal weight were tested. The properties of bio oil also were characterized using FTIR and GC-MS spectroscopy methods. The maximum yield of bio oil obtained using C.glomerata and F.vesiculosus were 0.134 and 0.195 using methanol solvent.

The ill-condition of stiffness matrix at the unstable region for example at the strain-softening region, the load control method will not be valid to give the solution therefore the displacement control method is essential to use. The stiffness matrix is changed at different steps by used load control and solution is found using any nonlinear solution method of Newton’s family. Therefore, Newton’s method will not give a solution to the unstable region. The iteration method and solution process may also stop when the diagonal element of the stiffness matrix becomes negative or zero if Newton's method is adopted. These difficulties need to be overcome and a non-positive definite stiffness matrix is retained and used for iteration in the arc-length method. A scientific review of literature has been made to pinpoint the difficulties faced in the prediction of complete load-displacement response of structures and techniques available to overcome the same. Displacement control methods have been reviewed with emphases on the arc length methods which can be integrated with the traditional finite element method.

This study investigates the compressive strengths of concrete cubes and reinforced columns cast with partial replacement of cement using 0- 25 wt.% Aluminum dross (AlDr) and cured in Lagoon water for 7-42days and 1-6 months respectively. The results indicated cubes with 5 wt.% AlDr, 10 wt. % AlDr and control possess strength of 15N/mm2,14.59N/mm2 and 13.48N/mm2 respectively at 28-day curing while at 42-day the results are 16.89N/mm2, 12.22N/mm2 and 16.96N/mm2 for control, 5 and 10 wt.% AlDr respectively. The 42-day compressive strength (79.48%) confirmed the performance at 28-day strength (75%). Control cube (74.6-95.5%) has higher crystallinity compared to cement (65.1-90.1%) and AlDr (62.4-74.0%) but at 15 wt.% AlDr concrete the crystallinity (78.1-96.2%) is superior with marginal crystal sizes variation (12.8-16.9). The strength (~9.5 N/mm2) with 10 wt. % AlDr column cured for 6 months was better than the control columns environment (~7 N/mm2) at 2-month.

A finite volume analysis of laminar natural convection of air within full parabolic enclosures heated from below is reported for the enclosure aspect ratio 0.27 £ AR £ 0.7 and a range of the Rayleigh number 5.5 x 106 £ Ra £ 9.8 x 107. The shape of the enclosures strongly affects the results obtained. Quasi-symmetrically arranged counter-rotating vortices are formed in each of the enclosures. The shape of the cells are influenced by the bounding curved and flat surfaces as they change from being rectangular at the periphery to circular at the core. There are reduction in the size and intensity of the on the cells from the center to the bottom corners. At steady state, there exists in each enclosure a central thermal plume that thickens as the roof pitch angle increases. The heat transfer pattern matches the flow of the plumes and jets from the walls. For the 15o roof pitch enclosure, the heat transfer rate increases sharply at a critical Ra value of 5 x 106.