Vol. 6 No. 4 (2013)
Articles
Abstract: Although the earth crust is not rich with Lead element but large quantities have been released into environment as a result of humanity activities in particular through the last decades. Consumption of gasoline plays a rule in increasing the concentration levels in the atmosphere in radical change, that cease of using fuel type leaded gasoline in vehicles such as tetraethyl lead (TEL) and tetramethyl lead (TML) to improve the octane number and as an inhibitor to knocking phenomenon that happened in gasoline engines. Our research aimed to determine concentration levels of lead in gasoline available in the local gasoline stations in Baghdad city and its impact on the environment. Eleven gasoline samples were gathered from gasoline stations spreading in Baghdad city. Six of which in Karkh site: Al-Autaifaih, Al-Hurai, Al-Latifaih, Al-Yarmook, Mulla-Howaish, and Umo-Altobule gasoline stations. And other five in Rusafa site: Al-Solaikh, Vegetable Oils, Al-Kamalai, Al-Saadre City, and Al-Kailany gasoline stations. In this research the reaction of alkyl lead compound with solution of tricaprylmethyl ammonium chloride ( Aliquat 336 ) and iodine I2 that dissolved in isobutyl ketone (MIBK) have been used to increase the stability of lead ions in the samples solutions that were subjected to tests using atomic absorption (AAS) technique. Standard calibration curve for lead has been drawn, so by using the rectilinear equation for the given standard curve the level of total alkyl lead in gasoline samples was estimated. By this work it was found that the content of alkyl lead in some gasoline samples approaches the 7 mg/L or the gasoline lead free ( references of this research ) and other samples below this range, whereas the higher concentration in samples that were subjected to test have been denoted to pollution to the gasoline was occurred from previous additions. Our research references also denoted that concentration of 500 mg/L of alkyl lead must be added to the gasoline fuel in order to increase its performance. Using the procedure that has been used in our work the minimum level of alkyl lead in gasoline samples was found equal to 0.17 mg/L and the maximum value of alkyl lead was found equal to 43.69 mg/L. These levels of alkyl lead found in our research are below the natural additions that give higher performance of gasoline product toward vehicles of gasoline engines
Abstract: The aim of this study is to investigate the effect of two of oil products (kerosene and fuel oil which is locally called as black oil) on compressive strength of reactive powder concrete (RPC). RPC was prepared using cement, silica fume, fine sand, steel fibers and superplasticizer to cast and test 63 specimens of cubes with various steel fibers ratios of 0%, 1% and 2% at different exposure times in oil products (0, 30, 90 and 180) days. In general the results showed that RPC has good resistance to the effect of kerosene and fuel oil. A slight decrease in compressive strength occurred as the time of exposure to the oil products increases. The RPC specimens of 2% steel fibers content had the lower decrease in compressive strength as a result of the denser microstructure. The decreasing ratio of RPC compressive strength exposed to fuel oil (1.33%) was lower than that of kerosene (2.91%). This may be attributed to the lower viscosity of kerosene than fuel oil.
Abstract: The mechanical behavior of filled elastomeric materials (rubber or rubber-like materials) is known to be incompressible, or nearly-incompressible, hyperelastic and time-dependent, or viscoelastic. This complex behavior of rubbery materials needs more understanding, and a good knowledge is required for such behavior in order to attain a constitutive modeling for better design of a rubber component for a specific application. To achieve this objective, theoretical and experimental works are presented in this paper. Theoretical works are considered for modeling the hyperelastic and viscoelastic behaviors of rubber. The hyperelastic behavior is modeled using Mooney–Rivlin constitutive model. While the time-dependent behavior (viscoelasticity) was modeled by using Prony series. Modeling and parameters identification, for both hyperelastic and viscoelastic behaviors, were performed and compared with ANSYS 14. To do this, different tests were performed on filled rubber in the present work, all tests were performed on filled rubber material with three different kinds of carbon black, N326, N375, and N660 at room temperature. Tensile stress-stretch curves were generated from the test data at strain rates 10 mm/min. Relaxation stress-time curves were generated from the test data at mean strain (200%) from the effective length of the specimen, at constant strain rate (200 mm/min). From the work it is found that a two-term Mooney-Riviln adequately describes the hyperelasticity of the material. The numerical results, using ANSYS, exhibit good agreement with experimental data.
Abstract: The main objective of the research reported in this paper was to present an experimental and analytical study for the effect of external strengthening by CFRP laminates on the behavior of beams containing tensile reinforcement lap splices such as ultimate load, ductility and mode of failure. To meet the objective, seventeen NSC beam specimens were tested with cross section of (200x300) mm and overall length 2100mm. Each beam was designed with bars spliced in a constant moment region at midspan. The variables used in the investigation were bar size, presence of transverse reinforcement in the splice region and strengthening scheme by CFRP laminates. From the experimental study the results show that the use of CFRP sheet to upgrade the R.C beams containing tensile reinforcement lap splices has significant effect on the behavior of these beams such as ultimate load, cracking load, deflection and mode of failure where the percent increase in ultimate load was about (11-47)% and with elimination the possibility of the brittle failure. Analytically, three dimensional finite element were used to analyze these members by nonlinear solution technique. ANSYS computer program (version 9.0, 2004) was performed throughout this study. Eight-node brick element has been used to model concrete, two node link element has been used to model steel reinforcement and four node shell element was used to model CFRP straps. The bond between steel reinforcement and concrete has been modeled by using two-node contact element (CONTAC52). The comparison between the experimental and analytical results referred to reasonable agreement and asserted the validity of the numerical analysis and methodology developed in this study with difference by about 10% for ultimate load and 16% for maximum deflection with good estimation for mode of failure
Abstract: This research studies the heat transfer in porous medium experimentally. Experimental investigation is carried out of free convection heat transfer for three dimensional in a box. The box filled with saturated porous medium, manufactured from glass with dimensions (30 × 30 × 30) cm. The porous media of plastic balls is used with homogeneous in diameter (11.7 mm). The lower wall of the box is heated by an electrical heater, while the other walls are thermally isolated. The effect of a porous medium on free convection heat transfer is studied for five values of heat fluxes (348, 576, 839, 1147, and 1384W/m2).Rayleigh number is ranging between () and for average Nusselt number between (). The results showed that the temperature inside the space increases as Rayleigh number increases. Also, the average Nusselt number increases with increase of Rayleigh number for the first three values of heat flux, but it decreases after heat flux because of domination of the conduction heat transfer on convection heat transfer. Also an empirical correlations were obtained in this study.
Abstract: Drip irrigation system can apply frequent and small amounts of irrigation water at many points of a field surface/subsurface near the plants with drip irrigation, plant water and fertilizer requirements can also be applied to the plant root zone with minimum losses, maintaining steady moisture in the soil profile. In addition, drip irrigation systems have the advantage of fitting difficult topography. The research studied drip irrigation system (looped with carrier network) in analogue system, to generate data by using analogue system, it an electrical board is constructed to simulate the field network. That means to use thermal wires to simulate the laterals, and resistances to simulate the emitters. A relationship has been concluded through the derived equation between the emitters discharge and resistance voltage. Comparing both equations that are derived from the field, a new relative equation has been concluded; with a new relative reflect the head and current relationships. The analogue results confirm the field results by using three types of emitters (Turbo, Adjustable flow drippers and Long-Path emitter). The field results took from studied at 2010
Abstract: Fine aggregate contaminated with interior sulfates is an important problem of concrete manufacture in Iraq. It is difficult to obtain well graded fine aggregate with sulfates content within standard specifications. The main objective of this study is to investigate the effect of internal sulfates in sand on some properties of self compacting concrete (SCC) by adding natural gypsum to fine aggregate as a partial replacement by weight. In this work, two basic categories of selfcompacting concrete are used: (SCC) incorporating limestone powder (LSP) and SCC incorporating 10% high reactivity metakaolin (HRM) Class N plus limestone powder(LSP) .Four levels of sulfates contents in fine aggregate were investigated, these levels were ( 0.37, 0.5, 1.0, and 1.5)% which it is equal to(3.74, 3.99, 4.96 and 5.93)% by weight of cement for mixes contained limestone powder (LSP) and it is equal to (3.76, 4.01,4.98 and 5.96) % by weight of cement for mixes contains high reactivity metakaolin (HRM) Class N plus limestone powder(LSP). The experimental program is divided into two parts; the first part is devoted to produce self compacting concrete by using superplasticizers and fillers then determine the workability. Different test methods are adopted such as slump flow and T50 cm, V-funnel, VFunnel at T5 minutes, L-box and sieve segregation test. The second part is devoted to study the mechanical properties such as the compressive strength and splitting tensile strength. The results obtained from this work show that the optimum gypsum content was 0.5% by weight of fine aggregate for all mixes which gives increases in the compressive strength by a range(5.9 -10.1)% and in the splitting tensile strength by a range (1.2 – 8.5 )% for mixes of (SSC) with (LSP) and (LSP +HRM).
Abstract: Copper oxide (CuO) thin films were prepared by cold spray process using inert atmosphere (helium gas) without employing any catalyst. CuO dry powder was sprayed onto microscope glass slide by heating carrier gas at 100, 200, 300, and 400 °C ,with 30 bar gas pressure onto substrates of 300 ± 5°C at different angles 0°, 30°, 45°, then study the effect of these parameter on the structural, and optical properties of the resulted thin film. The X-ray diffraction (XRD) studies showed that the as-deposited CuO has the monoclinic structure with low strain. SEM images show that the thin film has no porosity or agglomeration and deposit on the entire region. The CuO thin film exhibited a high transmittance of about (96%)
Abstract: Radon gas is unstable, it releases energy by emitting alpha particles, and is soluble in water and is often found in the ground water. Decays of radon emits alpha particles and beta particles. The energy released from these decay products results in damage to biological tissues which may lead to cancer. The health consequences of radon are well documented. Measurements of natural radioactivity in soil and ground water have been studied. Radionuclides present in soil include Ra226 , Th232 , and K40. Gamma rays dose depends on the geological and geographical and appears in many levels in soils , the knowledge of gamma distribution in soils and well water play important role for protection against radiation. Drilling company drills 4 wells in Babylon Institute. Doses, statistical information's about these wells are studied, also contours between real and estimated values are drawn. Testes are done in Babylon Environmental Office