AL-Rafidain Engineering Journal (AREJ)

Concrete behavior subjected to repeated loads is differs than the one subjected to static loads. Repeated loads caused crushing in some part of concrete due to loading and unloading process. Concrete behavior under static loads is affected by adding steel fibers, which improved many properties especially concrete tensile strength. These improvements are studied in this research under the effect of repeated loads, by testing simply supported fibrous reinforced concrete beams with dimensions (1000x150x160) mm, reinforced with different percentages of steel fibers (0.0, 0.5, 0.75, and 1.0%). Repeated loads were applied to the beams through two points and for many cycles up to failure. The physical properties and compressive strength of the concrete used was found by casting standard cylinders (150x300) mm for the different percentages of fibers. All the results show improvements in beams behavior due to fiber addition to the concrete under repeated loads, by increasing the deflection, strain, ductility and energy dissipation due to increasing of added fibers percentages

In this paper, a comprehensive practical test to a Wireless Internet Service Provider (WISP) system is presented. The structure of the system is investigated and its performance is measured for different time units ranging from a Day to a Year periods. The effect of the different parameters on the system behavior is determined and their contribution is detected. The goal of this study is to give a realistic picture to the behavior of such a system as a result of its users demands, network infrastructure and service management techniques.

In this research, (192) concrete cubes were taken from different concrete mixes incorporating coarse and fine aggregate from four different sources with two types of cement; Iraqi cement & Turkish cement. The compressive strength of these cubes was examined to know the most suitable materials to product good concrete for use in the projects of Tikrit University. The results indicate that, the aggregate from Al-Mosul source gives compressive strength higher than the aggregate from other sources. The Turkish cement gives compressive strength higher than that given by Iraqi cement.

An FPGA real time Implementation of Time Delay Neural Network (TDNN) is presented in this paper. The design and all of the work are geared towards the implementation of the TDNN in a scalable fashion. The TDNN is an adaptive FIR filter with 18-bit input and 18-bit output resolution. In this paper, the filter adapts its tap weights using the Least-Mean-Square (LMS) algorithm and then stores them in FPGA memory cell. The LMS algorithm that is used for weight adaptation is off chip implemented. The input is processed through a digital tapped delay line. The FIR neural network is used for real time adaptive noise cancellation. When the filter order is 10, the filter consumes 1168 Spartan 3E FPGA logic elements

The research studies the impact of Mosul Dam Lake on the climate of Mosul city, and comparison of the climate before and after the lake establishment. Monthly values of various climatic elements were analyzed for a period of twenty years before the establishment (1966-1985) and twenty years after it(1986-2005).The analysis shows that there is an increase in cooling capacity calculated, according to the equation Cena et. al. after the establishment and at a rate ranging between (5 -24)% in most months but not in summer months and September. It is found that the value of P/E is also increased in this period compared with that before the establishment. this value increases in winter months compared with the other months with low this percentage to reach zero during the summer months. In addition, there is an increase in the quantity of rainfall during winter months and March which highly affects wheat and barley growth in the region, whereas the comparison between the two periods concerning the amount of rainfall in spring and Autumn months is very simple. Quantity of evaporation increases gradually after January and reaches its highest values in June and July then it starts decreasing.. There is no difference between the two periods except for quantities of evaporation a where a noticeable increase in June and July by 30% in the second period after the establishment. Furthermore, a significant increase in wind acceleration is also observed after the establishment especially during November, December, January, February and March,. this increase is ranged between (56-67%) while during April, May and October, it is ranged (36-45)%.the summer and September, the rate of increase is minor compared to other months.

this paper, circular contourlet transform (CCT) is proposed, designed and realized. As in the classical contourlet transform (CT), a double filter bank structure is also considered in this work but in different manners. A circularly-decomposed filter bank is first used to capture the points of discontinuities in the image edges, and then followed by a directional filter bank to obtain smoothed contours. The resulting CCT contains a critically sampled filter bank that decomposes images into any power of two's number of directional subbands at multiple scales. The designed CCT is realized by 2-D lattice allpass sections with separable and non-separable 2-D functions of z1 and z2. The resulting structure preserves both modularity and regularity properties which are suitable for VLSI implementations. Objectively, the performances of the realized CCT are tested and proved to be better than the classical CT in detail image preservation. The resulting subband images also indicate the superiority of the proposed CCT.

In this study the effect of adding pure ethanol (99.2%) to leaded gasoline on the performance of spark ignition engine have been investigated. All tests were carried out using ethanol- leaded gasoline blends ( E10, E20, E30, E40 and E50) at various compression ratio ( 9:1, 10:1 and 11:1) for different ignition time ( 0º TDC- 30º BTDC), engine speed of 2000 rpm and an equivalence ratio ) ).The experimental results showed that blending leaded gasoline with ethanol slightly increased the torque , specific fuel consumption and exhaust gas temperature and in particular when E30, E40 and E50 blends are used. However, results also shows a significant reduction in exhaust emission for high percentage ethanol-gasoline blend, i.e for E30, E40 and E50. In addition to all that blending gasoline with ethanol allows engine to operate at high compression ratio without knock occurrence.

This research work includes an experimental investigation to study the effect of high temperatures on the mechanical properties of concrete containing admixtures. A comparative study was conducted on concrete mixes, reference mix without an additive and that with an admixture. Concrete was exposed to three levels of high temperatures (200,400,600) °C, for a duration of one hour, without any imposed load during the heating. Five types of admixtures were used, superplasticizer, plasticizer, retarder and water reducing admixture, an accelerator and an air entraining admixture. Mechanical properties of concrete were studied at different high temperatures, including: compressive strength, splitting tensile strength, modulus of elasticity and ultimate strain. Test results showed a reduction in the studied properties by different rates for different additives and for each temperature, the decrease was very limited at temperature up to (200°C) but was clear at (400,600) °C.

This research include a practical study on the effect of pre-annealing in different conditions and the number of forming steps on the formability of low carbon steel sheet of thickness(10)mm which is widely used due to popular industrial uses especially in the cold pressing processes. A particular specimens were annealed at different temperatures then a set of tests were applied on these specimen. It was noticed that the annealing improve the ductility of the specimens especially the temperature that equal to 550°C with (12) minute soaking time which gave the best ability of cold pressing for the specimen . Also it was found that use of two steps of cold pressing with annealing between improve the formability of the specimen as compared with the single step of cold pressing.

This paper provides a method of changing the effective value of the capacitor for starting a single phase induction motor starting. This capacitor is connected in series with the auxiliary winding. Its effective value can be controlled by static switches in parallel with the capacitor through a series of pulses. The focus was on finding ways of obtaining the best effective capacitor during starting condition through computer simulation software using (Matlab). By using this method, only one capacitor is used for both the starting and running conditions and a similar starting performance can be obtained when compared with the conventional method using two capacitors. The computer simulation results are validated by building a laboratory model and comparison of results

In the present work nonlinear finite element program written in fortran language to simulate the behavior of masonry wall under the action of monotonic loading has been developed. The masonry is modeled as a two-phase material, treating bricks and mortar joints separately, thus allowing for nonlinear deformation characteristic and progressive local failure of both bricks and mortar joints. The influence of the mortar joint is taken into account by using an interface cap model as a part of a rational unit-joint model able to describe cracking, slipping and crushing of the material. The capabilities of the program have been examined and demonstrated by analyzing two different types of masonry wall. The accuracy of the analytical results was assessed by comparing them with the experimental results and shown to be good.

Many of modern studies attached special importance to the phenomenon of employing tradition in Architecture generally, and in Arabic region especially, because it considered as a tool for reviving societies, as it has rational and human principles which could be employed, therefore it was the problem area for this research, trying to recognize it first, and come out with theoretical framework by scrutiny in previous studies in this context second, it appears that items of theoretical framework related with conceptual principles which architects believes toward tradition employing, formulations and degree of employing, and finally employing mechanisms . The research appliance for framework items in practical study was aiming to test it scientifically, and it chosen the Architect Rasem Badran to show his specialty. The findings show that Badarn has fixed conceptual principle in tradition employing which was the evolving interpretative one, which related with certain values to the rest of theoretical framework items. The conclusions proved the research hypotheses, and confirm thinkers viewpoints about Badran especially, as he respects and dignifies tradition, therefore architects could apply Badran's manner in their new products, but the conclusions also rises many questions about preciseness of previous classifications dealing with conceptual principles for the architects and there belonging to it .

One of the main feature of wireless cellular network is to achieve continuous (uninterrupted) services using handoff when mobile subscribers cross the boundaries of cells in the coverage area. Handoff calls are usually given higher priority than new calls initiated.Various algorithms are investigated using simulation and the results obtained show that the received signal strength with hysteresis and threshold in the serving cell (RSS-HTser.) and the received signal strength with hysteresis and threshold in the new cell (RSS-HTnew.) are the two methods which are closely representing the cellular system environment since they contain additional constrains in Handoff (HO) execution. Simulation are carried out by varying the governing parameters including the effects of fading on the received signal strength, averaging of signal strength, hysteresis and threshold, window size on average signal strength, and the standard deviation which represent worsening signal fading.

The basic urban residence pattern changes in Iraq during the previous century have formed a foundation for a basic problems in its facade ability to provide environmental privacy and specially in its role as a physical filter to provide the thermal control inside the house.This research is trying , through the benefit of analyzing the residential reality product ,to criticize the indices of the precedent local studies which try to solve this problem and its application difficulties in the residential reality. and offer its real indices to improve the climatic control system through the residential façade, which could be implied in the future housing projects, integrated with the other resident needs in façade.

In the present study the effect of drawing ratio in deep drawing process on the thickness distribution along the cup (wall, base and nose) has been performed. Obviously, the drawing ratio is the one of the most important parameter has been adopted to design the drawing die. Both experimental and numerical models were carried out on various drawing ratios (1.484, 1.589, 1.739, 1.908, 2.12 and 2.332).Tthe simulation results showed that the best drawing ratio is 1.484, which gives small difference between maximum and minimum thickness distribution along the cup. To examine the simulation results, experimental tests were performed one of the drawing ratios which shows the same behavior and pattern approximately.