Articles in This Issue
Abstract
Thousands of tons of marble waste can be reused every year in Iraq. Few investigations are made to study the effect of marble as a filler on hot mix asphalt concrete.. This big amount of waste has a bad effect on the environment and needs a lot of money and effort for recycling or disposal. Lime stone dust was used as a control filler. The laboratory tests have been conducted in order to evaluate the properties of each type of filler, which consist of the grain size distribution, the specific gravity (Gs), specific surface area (SA), pore volume(PV), mineral composition, pH and chemical composition.To study the effect of SM on the performance of HMA mixture, several tests were made consist of Marshall stiffness, Indirect tensile strength, Moisture susceptibility and Creep tests. Many conclusions were achieved referring the importance of using Sulaimania Marble waste (SM) in the enhancing most of the properties of HMA concrete.
Abstract
In most cases, the concrete wall panels are subjected to axial eccentric distributed loading; due to this type of loading, concrete wall panels behave and fail somehow. There are many parameters that affect the structural behavior of the concrete wall panels. This study presents experimental investigation the structural behavior of concrete wall panels subjected to axial eccentric distributed loading; also evaluates the effect of the parameters, slenderness ratio (H/t), aspect ratio (H/L) and concrete strength on the behavior of concrete wall panels. The experimental program includes testing fifteen concrete wall panels hinged at top and bottom with free sides, by applying the load axially with eccentricity equal to (t/6); these panels are divided into five groups, each group consists of three panels with slenderness ratio (H/t) equals to (20 , 25 , 30) for each panel, three groups of normal concrete strength with aspect ratio (H/L) equal to (1.0 , 1.5 . 2.0) for each group and the other two groups are of high strength concrete with aspect ratio (H/L) equal to 2.0 for both two groups. The deflections of concrete wall panels depend on the slenderness ratio (H/t), aspect ratio (H/L) and concrete strength. The failure mode of the concrete wall panels is greatly affected by the aspect ratio (H/L); the panels with low aspect ratio tend to fail by crushing, while panels with high aspect ratio tends to fail by buckling.
Abstract
This research investigates the impact resistace of reinforced high strength concrete slabs with steel meshes (BRC) modified by styrene butadiene rubber (SBR) with different weight ratios of polymer to cement as follows: 3%, 5% and 7%. Reference mix was produced for comparison of results. For all selected mixes, cubes (100×100×100mm) were made for compressive strength test at (365) days. In conducting low-velocity impact test, method of repeated falling mass was used: 1400gm steel ball falling freely from height of 2400mm on reinforced panels of (50×50×800 mm) reinforced with one layer of (BRC). The number of blows causing first crack and final perforation (failure) were calculated, according to the former results, the energy of each case was found. Results showed an improvement in compressive strength of polymer modified high strength concrete (PMHSC) over reference mix; the maximum increase being of it were (3.93%-11.96%) at age of (365) days. There is significant improvement in low-velocity impact resistance of all polymer modified mixes over reference mix. Results illustrated that polymer modified mix of (3%) give the its higher impact resistance than others, the increase of its impact resistance at failure over reference mix was (154.76%) while, for polymer modified mix (5%) it was (30.95%) and it was (14.28%) for polymer modified mix of (7%).
Abstract
This paper presents an analytical investigation which includes the use of three dimensional nonlinear finite elements to model the performance of the space trusses by using (ANSYS 11.0) computer program. The numerical results show very good agreement (100%) with experimental results, while the graphical option reflects the behavior of the structure under the applied loads because of the ability of this option to simulate the real behavior of the structure under these loads. Also finite element models of the space truss simulate the lateral deflection of the top chord members especially at the corners, and the twisting of the bottom chords.
Abstract
The aim of this paper is to study experimentally the effect of steel fibers content on the modulus of elasticity of High Performance concrete HPC in different curing age. The results showed that adding steel fibers to HPC led to a considerable improvement in static and dynamic modulus of elasticity where at 90 day water curing the percentages of increasing in static modulus of elasticity of High Performance Steel Fiber Concrete HPSFC relative to HPC were 8.2%, 9.98%, and 11.88% at 0.5%, 1%, and 1.5% steel fibers by total concrete volume, respectively. While, the improvement of dynamic modulus of elasticity of HPSFC relative to HPC at 28 day were 8.09%, 10.7%, and 11.07% % at 0.5 %, 1 %, and 1.5 % respectively.
Abstract
Linearised dynamic analysis of beams subjected to lateral forces and composed of materials which have different moduli in tension and compression is presented. The position of the neutral surface was rendered independent of the spatial and temporal coordinates by introducing a special assumption which reduced the coupled nonlinear problem of the flexure of such a beam into a linear one. The actual position then became a function of section geometry and the two elastic moduli and was determined by the equivalent section method. The elemental dynamic stiffness matrix was derived using the exact displacement shape functions governed by the governing partial differential equation and the structural stiffness matrix was assembled according to the usual assembling methodology of structural analysis. Symbolic and numerical examples were solved to show the applicability and efficacy of the proposed method.
Abstract
The research evaluated the wastewater effluents , Two pump stations discharged directly without any treatment in AL-WARAR Canal in Ramadi City ,located in the southern bank of the Canal . These effluents collects the storm water from the residential area , the drainage open channel which bypassing by septic tanks of domestic wastewater , bypassing from septic tanks of domestic wastewater. Laboratory Tests out on (December 2010 to May 2011) for the Canal (upstream) , wastewater effluents, and Canal ( downstream) to determine the quality characteristics and the wastewater effects upon the AL-WARAR Canal . The results show an increase in almost concentrations of characteristics compared to the Iraqi Standards NO. (25 –B1) in (1967) of the conservation of water resources , where the Bio-chemical oxygen demand , chemical oxygen demand and Total Bacterial Count were increased by (11, 9.7 and 535) times respectively. According to the organic load , the wastewater effluents classified as low strength . This study shows that the value of the reaction constant rate (k1) and Reaeration constant rate (k2)were about (0.187/day) and (0.556 /day ) respectively . Two stations downstream were located to determine the wastewater effects upon the Canal , Dissolved Oxygen was measured and calculated by using (STREETER –PHELPS) equations , then Sag curve of AL-WARAR Canal was determined .In spite of that the wastewater effluent does not comply with the Iraqi Standards discharged into water resources NO. (25 –B1) in (1967) , AL-WARAR Canal still comply with the Iraqi standards (NO. 25-A1) in (1967) of the conservation of water resources by the effect of self-purifications.
Abstract
Many studies were achieved in order to improve water efficiency treatment and to remove high turbidity by using Coagulants like Alum with Coagulants aid like polymers. Many researches explain the effect of these polymers on the removal of high water turbidity over the past years attempting to improve the coagulation and flocculation processes. Several experiments were performed to investigate the effect of using other types of coagulants aid on the percentage removal of turbidity and to find the optimum dosage of coagulant (alum) and coagulant aid. The coagulants used in this study were alum, Porcelanite and Silica Gel which are used in general company of ceramic and glass factory in Ramadi City as liquid state .The initial turbidity at 450 NTU was used with floc growth and floc formation was studied for Kaolinite 10 µm particles size. The results were obtained and plotted to show the effect of using different dosages of the mentioned coagulants on the residual and percentage removal of turbidity. Also, other parameters like TDS, Ec, pH and salt were calculated. The results indicated that the efficient coagulant type with dose of 30 mg/l is 4.56 NTU residual turbidity and removal percentage of 98.98% by using alum with silica, with the percentage of alum is 60% and 40% of Silica and pH value 7.66.
Abstract
Rising energy prices and growing environmental concerns are making solar electric systems more attractive to homeowners. A solar electric system reduces high energy costs and keeps your home up and running during power out-ages. The advantages to buying a solar electric system include: Saving a significant amount on your electric bill. Increasing your home’s appraisal value. Enjoying reliable, clean, free power for 25 to 30 years. Helping and assist to boost our economy by creating jobs and new solar companies. A solar electric system is typically made up of solar panels, an inverter, battery, charge controller, wiring, and support structure. The three most common types of solar electric systems are grid-connected, grid-connected with battery backup, and off-grid (stand-alone). This work presents design and analysis of high performance of home solar energy, that include: the orientation and pitch of the southernmost facing roof to maximize solar gain, the roof vents, chimneys, gables or other obstructions in order to sit to the north side of the planned array. Ensure that the roof structure is strong enough. Structural support into the roof to handle the weight of a rack-mounted system. The space for inverters and disconnects near the main service panel. Finally comparison between these systems with other sources of energy.
Abstract
This research provides a comparison between the performances of Sugeno type versus Mamdani-type fuzzy inference systems. The main motivation behind this research was to assess which approach provides the best performance for satellite image classification. The performance of each approach has been evaluated for six bands (from Landsat-5) for West Iraq image classification and compared with traditional method (Maximum likelihood), based on pixel-by-pixel technique. Due to the importance of performance in online systems we compare the Mamdani model, used previously, with a Sugeno formulation using four types of membership function (MF) generation methods. The first method triangular membership function using the mean, minimum and maximum of the histogram attribute values. The second approach generates triangular membership function using the peak and the standard deviation of attributes values. The third procedure generates Gaussian membership function using the mean and the standard deviation of the histogram attributes values. The fourth approach generates Gaussian membership function using the peak and the standard deviation of the histogram attributes values. The results show that the Mamdani models perform better in most of the case under study.
Abstract
The world is moving now to the energy of water to generate electric power and too much on several considerations, most important is that this energy is a clean and renewable energies as well as reasonably available. So we are going to create a small hydro power stations with limited power can be linked via the national grid or the completion of feeding limited areas to ease the load on the national network in addition to low cost of establishment and the costs of power processed. And now that we need t this specification at this stage and the availability of waterways and weirs in the governorate of AL-anbar has been building this research. We have in this search by selecting the barrage of Fallujah for the establishment of a hydroelectric plant it was a survey of geographical and engineering on the site of this barrage was recorded the water levels over the full year and found that the height of the water in which at least 3.5 meters, so the choice of equipment needed to build a hydroelectric plant with capacity of (140) KW aided with catalogues of well known international companies and accredited globally.
Abstract
The corrosion of reinforcement iron is one of the dangerous problems in middle and west of Iraq and Arabian gulf which is needed to large investigations because of increasing of chloride salts in soil and ground water and rising of temperature at summer which encourage of finding the shrinkage cracks in their two types : Plastic and drying shrinkage . cracks are easy way for harmful ions present at soil and ground water to enter through reinforced concrete making damage for protection film a rounding rein forced iron and led to rust with cracks in concrete cover a rounding rein forced iron added to its may be to cause structural damage in members of rein forced concrete because of absence of a adhesive between concrete and steel leading to structural failure . This research presents study for this problem and knowing their causes and methods to reduce it. Experimental work show that the concrete exposed to chlorides leads to decreasing in density with ratio (1.5%) and decreasing in flextural strength with ratio (138%) at age (28) day .