حيدر عباس علي اليوسفي

Recently, the use of recycled plastic waste in civil engineering applications has been increased. This paper aims to investigate the effect of water-cement ratio on the compressive strength of concrete that contents 2.5 % polypropylene (P.P) as plastic waste. Two references concrete mixes were prepared. The first mix had a water-cement ratio of 0.45 with 2.5% plastic waste, the second mix with 0.45 water cement ratio but without plastic waste. Three concrete mixes with water cement ratios of (0.5, 0.4, and 0.3) were also used as parametric study cases. The results indicated that decreasing the water-cement ratio from 0.45 to 0.4 increases the compressive strength by 20.2%. In addition, the compressive strength increases by 36.2% with decreasing of water cement ratio from 0.45 to 0.3. While the compressive strength decreases by 12% with the increase of water-cement ratio from 0.45 to 0.5.

A new experimental and numerical study was presented to investigate the effect of downstream spillway face's angle on the stilling basin’s energy dissipation (ED) efficiency. Six composed physical plywood models with downstream slopes of spillway face ranged from 30o to 55o for the spillway was built and used in the experimental tests. The hydraulic parameters of the flow were measured and the ED has calculated accordingly. The experimental results showed that the relative energy dissipation (RED) of the flow on the stilling basin decreased when the discharge was increased. On the other hand, the energy dissipation increased when the angle of the downstream face of the spillway was decreased. These models were simulated using 3-D Computational Fluid Dynamics (CFD) tool through (Flow-3D V.10.0.3) software. The comparison between the experimental work and numerical model indicated a significant convergence between them with R2 equals to 0.99.

There are several factors affect the determination of the best location for schools, however, it is very difficult to satisfy by one method for location determination. These factors can be classified to environmental, economic, technical and political social demands. In this study, a frame work, depended on analytic hierarchy process, for determination of the best location an ArcGIS10.1 software was applied to deal with geographical information system and uncertainty situations. Nine sets were used in this study: distance from emergency facilities, distance from existing schools, distance from roads, distance from rivers, distance from railway, distance from land use, distance from gas pipe and population density. Four scores then were found depending on normalizing of the nine sets: Unsuitable, Less Suitable, Suitable and Most Suitable areas. This research aims to find the best locations for primary schools by creating a model which applied into construction and making digital maps and hard copy for the schools that can be updated with demanded. Using GIS will make a huge development in selecting the locations of new schools and also can be applied in different other sectors.

ABSTRACT The current study examines the flow characteristics under free flow conditions over a crump weir. The impact of the side slopes of the weir on the coefficient of discharge (Cd) is taken into account. Four physical models with crest heights of 0.15 m under free flow circumstances and four upstream side slope (1:3, 1:2.5, 1:2 and 1:1.5) were used to investigate the impact of various variables on discharge coefficient (Cd). Using the dimensional analysis technique, the elements influencing the crump weir's discharge coefficient were determined based on laboratory tests. For the same flow rate, Cd value decrease by decreasing upstream side slope. It notices that a decrease in upstream slope (from 1:3 to 1:2.5) reducing Cd value about (2.61 %), decrease upstream slope from (1:3 to 1:2) reducing Cd value about (4.16 %) and when decrease upstream slope from (1:3 to 1:1.5) reducing Cd value about (5.81 %).

Abstract. This investigation aims to use corn cover as natural fibers in concrete mixes to improve some mechanical properties like compressive strength, tensile strength, and flexural strength. using any type of fiber in concrete, in general, can improve the tensile and flexural strength of concrete. Concrete is weak in tension, so using fibers such as natural fibers like trunk fibers or industrial fibers such as steel fibers can improve tensile, the flexural strength of concrete and that may be decreasing the use of steel reinforcement in concrete, and also fibers can improve toughness and ductility of concrete because of its work inside the concrete that can reduce the propagation of cracks under loading. This study shows slight improvement on compressive strength by using fibers, but high increments in flexural strength, the optimum ratio of corn cover fibers was 2.5% by weight of cement which gives the highest values in compressive strength and flexural strength. compressive strength increased from (31.2 to 35.9) MPa (about 15% increment), increment for flexural strength was 70.6% for the optimum fibers content and the failure by using corn fibers was a ductile failure compared with plain concrete that gives sudden failure under flexure load, also tensile strength increased by using fibers, more fibers content beyond or more than 2.5% give lower values for the mechanical properties.

In this research, an improvement in alternative heat transfer and thermal properties of ZnO nanoparticles (NPs)/ distilled water, DW nanofluid are experimentally studied and investigated. The two-step approach is utilized to prepare the ZnO NPs/water nanofluid using different concentrations and different inlet temperatures. Scanning Electron Microscopy (SEM) and UV–visible spectrophotometer is employed to characterize the nanofluid. Varying flow rates and the temperatures are examined in the heat exchanger's horizontial tube and shell pipe as well as the impacts of ZnO nanoparticles and the temperatures are studied on nanofluid's thermal conductivity and viscosity. The findings show improvements in the thermal conductivity of ZnO NPs / DW nanofluid. A maximum value of 6.67% of the thermal conductivity is achieved at a temperature of 343K using 1 % ZnO NPs. Nusselt Number also shown an improvement of 38% at a temperature of 343K using 0.2% wt of ZnO NPs under the turbulent condition (Reynolds Number range of 8000 to 20000). Experimental results are compared with previous correlations and an acceptable agreement is observed.