KUFA JOURNAL OF ENGINEERING

Local scour downstream of hydraulic structures, such as low head and high head structures, spillways, and culverts is an important research field due to its significant practical value. In this study laboratory experiments were conducted to compute the local scour downstream apron of an ogee spillway under different slopes of apron to study its effect on the characteristics of the scour. Developed physical models for spillway and aprons are installed into the water in the channel where conducted under subcritical flow and clear-water condition by using uniform cohesionless (soil) as bed material with a medium grain size (d50 = 0.65 mm).

Four angles of an apron were used (0 ̊, 2.73 ̊, 5.19 ̊, and 7.43 ̊) to show the effect of the slope for apron on local scour. It is found that the slope of an apron is one of the important parameter to reduce the local scour depth and the extent of scour hole. The influence of slope for aprons angle showed a reduction of about (53, 46, and 35) % in the maximum scour depth and about (33, 49, and 33) % in the maximum scour length compared with horizontal apron for angles (2.73 ̊, 5.19 ̊, and 7.43 ̊), respectively.

In this paper, an experimental study has been presented to investigate the effects of web opening on the behavior and failure of steel columns with cold formed thin walled sections (CFS) subjected to axial compressive load. Twenty small scale steel columns with cold formed box and channel sections and a total length of 500 mm have been considered in the experimental tests. Ten of the tested steel columns specimens have a box section with dimensions of (100×100×2) mm (height × width× thickness), and the other ten columns specimens have a channel sections with dimensions of (100×50×2) mm (height × width× thickness). To investigate the effect of the number and the shape of web opening on the axial compressive strength of steel columns, each ten columns with same cross section shape was divided into three groups of three columns in addition to the reference column which has no web openings. All groups of columns have same opening area which is located at the web of the section, but each group has a different opening shape (square, rectangular, and circular shapes), and each steel column within each group has different numbers of opening distributed along column length (one, two, and three openings). Each steel column specimens was subjected to an increasing static load up to column failure which indicated by the reloading of the test machine. The study has shown that for most of the tested columns, increasing the numbers of web openings results in decreasing the column axial strength compared to the reference steel column. The maximum percentage of the reduction in the columns axial compressive strength caused by the presence of web opening was found to be about 30% and 45% of the reference columns strength for columns with box and channel shape sections, respectively. It has also been found that the reduction in the axial compressive strength of the column specimens caused by the presence of web openings is lower for the circular shape openings compared to that for rectangular and/or square shape web openings.

The present work focused on the effect of glass fiber orientation that reinforced polymeric matrix in car bumper composite to understand the mechanical behavior of these materials during work conditions. Tensile test and bending test were performed and discussed for (0o, 30 o, 45 o, 60 o, and 90 o) angles of fibers orientation. The finite element method by program (ANSYS V.13 software) was used to study the behavior of these compounds. The results showed that the extension and deflection values were higher at (0o) and decreased with increasing fiber angle orientation until reached to a lower value at perpendicular state between fibers and applied loads. The study used to improve the mechanical properties of the composite materials depending on the fiber orientation angle.

This study aims to evaluate the management of medical solidwaste in some hospitals in Najaf city as a case study. For this study, three big local hospitals were selected that are different in specialties. The generation quantities of medical solidwaste were collected for one time in a week over four months (August - November 2010). The most important factors affecting the rate of generation of these wastes in selected hospitals were analyzed statistically to get a mathematical formula to calculate the amount of waste generated per day for each hospital. It is found that the generation rates were ranged from (1.074 - 3.844) Kg/capita/day through the study period. Due to the absence of regular application and workers conscious in management of medical solidwaste, the system management requires a safety environmental program to manage this waste, which minimizes the risks of public health and the environment.

There are many of industrial plasticizers materials used to improve mechanical properties of polypropylene. In this study chlorophyll, natural pigment is used. Its eco – friend and not toxic material, extracted from plants. The chlorophyll, natural pigment is extracted and mixed with polypropylene with following weight percentages (0.0, 0.1, 0.25, 0.5, 0.75, and 1.0), then extruded as a sheet by screw extrusion machine. The mechanical properties of specimens are examined by mechanical testing, such as (Tensile test, Impact test).

The results showed improvements in mechanical properties of polypropylene plasticized by chlorophyll. Where it gives ultimate tensile strength of (32.64, 33.972, 44.63, 40.633, 33.306, and 45.962) Mpa, the modulus of elasticity of (439.27, 1040, 1195.63, 700, 1785, and1525) Mpa, the maximum elongation % at fracture of (24.46, 16.182, 19.632, 61.584, 17.587, and 12.121) mm/mm %, and impact strength of (0.1, 0.2, 0.25, 0.355, 0.24, and 0.2) Joule, respectively with each chlorophyll addition weight percent wt%.

The polypropylene blend consisting chlorophyll of 0.5 wt % presents significant improvements of mechanical properties, high ductility, and impact strength, suitable ultimate strength, and modulus of elasticity.Â

There are several uses of granular soils in civil engineering works such as but not limited to under foundations structures, subbase course of roads, unpaved roads and soil embankments. This research attempts to overcome the problems of low-quality (by means of strength) of granular soil by enhancing California Bearing Ratio (CBR) test by utilizing geogrid. The research aim's to investigate the potential benefits of using the geogrid to improve CBR of granular soil. The results of tests showed that the granular soil under study was inferior than the materials comply on class C of Iraqi specifications for granular soil material. On the other hand, using of geogrid type Tensar SS2 at 0.15H (where H the total thickness of granular material samples) improves extremely the CBR value of the granular soil as it is increased by about three times in comparison with untreated soil.

The research presents ANN ("Artificial Neural Networks") estimation of confined peak strength for R.C columns. The modeling of the strength of reinforced concrete columns by uses of the (FEM) finite element method gets many difficulties, starting in geometric representation down to nonlinearities due to loads. The use of neural networks trained well can give us a model that can be utilized as an alternative and successful model for those columns. Experimental sets of data for concrete of square and circular concrete columns were gathered from many researches to develop an Artificial Neural Network formula as input data set parameters consist of ultimate strengths, size of mainly longitudinal and ties reinforcements, compressive concrete strength, thickness of concrete cover for reinforcement, specimen geometric dimension, and stirrup bars spacing. Confined Peaking Compressive Strength (CPCS) of square and circular concrete columns is predicted by neural networks technique and sorted with analytical models and found that they are scientifically accepted. The prediction was performed by package program (Mat Lap).

Environmental and economic considerations have encouraged civil engineers to find ways to reuse recycled materials in new constructions. The objective of this research was studying the possibility of utilizing recycled concrete RC in a surface course of hot mix asphalt HMA mixtures and evaluating the volumetric and mechanical properties of hot mix asphalt mixtures containing recycled concrete aggregates. For this purpose, the performance of HMA mixtures containing various percentages of RC has been evaluated based on experimental tests, such as Marshall Stability MS, Marshall flow, Marshall stiffness, and Indirect tensile strength ITS. 90 specimens contain 5% asphalt bitumen and RC in various percentages (10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%) were mixed with virgin crushed stone aggregates and compacted by using Marshall Compactor to produce HMA specimen then Marshall mix design method was used to measure the optimum RC content.The results of MS and flows slightly decreased with the addition of RC. Marshall stiffness values for 10 percent RC was higher than the Control Specimen CS and the others. ITS values decreased with increasing RC.A mixture without recycledconcrete RC and varies gradation of maximum size of ( 1/2,1, and 1/2) incheswas prepared as control mix to CM test the Marshall stability –flow , ITS, and temperature sensitivities properties of mixes with 58% ( optimum percent) of RC that is obtained from a mix design that was investigated in this study. Specimens showedslightly improvements in Marshall Stability, flow, and ITS as compared with CM.

In this investigation, the influence of using waste office paper fibers (WOPF) on the behavior of drying shrinkage in cement mortar have been presented. Cement mortar specimens size of (25×25×285) mm and a length change measuring apparatus including a dial gauge capable of measuring the length accurately to ±0.002 mmhave been used to study free drying shrinkage of cement mortar according to ASTM C596 –01 method.The workability of cement mortar reinforced with WOPF was assessed by using flow table test method. WOPF was added to the cement mortar in five ratios (0.2%, 0.4%, 0.6%, 0.8%, and 1%) by weight of cement with two categories. In first one WOPF added after being soaked in water for 24 hours while in the second one WOPF added after being soaked in cooking oil for 48 hours. The total mixes were 10 in addition to the reference mix (the 11thmix) which is made without WOPF. The results of the study indicated that the increase in WOPF ratio led to reduce in workability. In first category, when WOPF ratio increased to 0.4%, the flow percent still within 110±5%, and when WOPF ratio increased to 0.6% and above the flow percent clearly reduced. While in second category, when WOPF added, the flow percent dropped obviously for all ratios. Drying shrinkage percent increased when WOPF was added to mixes compared with reference mix for all ratios used in both categories except the fifth ratio (i.e. WOPF 1%) in which the drying shrinkage percent decreased at age of drying 11, 18, 25 days for first category and at age of 18 and 25 days for second category. Drying shrinkage percent of mixes has equal ratio of WOPF in the both categories had the same tendency in variation with time. The loss of weight percent variation for all the mixes is approximately linear. The loss of weight percent of category I is more than that of category II.

Fabrication of titanium dioxide (TiO2) thin film (200nm) has been done by using RF helicon magnetron sputtering from metallic Ti target under changing of O2 flow rate and substrate temperature. Film structure was measured by X-ray diffraction (XRD). The films were examined by an X-ray photoelectron spectroscopy (XPS) to study the structure; atomic force microscopy (AFM) and field-emission scanning electron microscope (FE-SEM) were employed to investigate the surface morphology and the cross section of films, respectively. Optical properties and optical band gap were calculated by using UV-VIS spectrophotometer. Photocatalytic activity was evaluated by light induced degradation of methylene blue (MB) solution using UV and Vis light. TiO2 thin film with a rutile phase at substrate temperature 100oC and O2 flow rate to 0.5 - 1.0sccm can be obtained, also an anatase phase can be fabricated when set substrate temperature to 300 oC and O2 flow rate to 2.5sccm. Obtained films showed a high dense with smooth surface and high crystalline. Maximum degradation rate (about 85%) of MB has been indicated at anatase phase under UV light irradiation, while under Vis light irradiation rutile and anatase mixture phase showed a maximum degradation rate (about 15%).

In this work, the morphological, structural, optical, and photocatalytic properties of TiO2 thin films that were fabricated by RF helicon magnetron sputtering under change of O2 flow rate and substrate temperature have been investigated. It is expected that the change of substrate temperature and/or O2 flow rate will make ability to control the film structure.