Strengthening of the existing structures is an important task that civil engineers continuously face. Compression members, especially columns, being the most important members of any structure, are the most important members to strengthen if the need ever arise. The method of strengthening compression members by direct wrapping by Carbon Fiber Reinforced Polymer (CFRP) was adopted in this research. Since the concrete material is a heterogeneous and complex in behavior, thus, the behavior of the confined compression members subjected to uniaxial stress is investigated by finite element (FE) models created using Abaqus CAE 2017 software. The aim of this research is to study experimentally and numerically, the behavior of square plain (without steel reinforcement) concrete compression members, that has concrete strength of = 24.41 MPa, confined with one layer of CFRP wraps under uniaxial compressive loading. Finally, the outcomes are compared with the finite element models using Abaqus software. Laboratory experimental results showed that confining compression members with CFRP wraps is an efficient strengthening method. In terms of load carrying capacity, an enhancement was measured for about 56.1% of the reference non-confined members. This enhancement was also reached using Abaqus software.
The thyroid gland is a vital part of the overall endocrine system, which is regulated some of body function as oxygen use, basal metabolic rate, growth, cellular metabolism and development This study shed light on a number of extracts that have been shown to have beneficial effects on the thyroid and its function, as well as the various factors linked to thyroid dysfunction. The experiment was conducted to determine the effect of a mixture of two extracts of "Fucus vesiculosus (150 mg/ kg) with Coleus forskohlii (1000 mg/ kg) and Rosmarinus officinalis (220 mg/ kg) with Camellia sinensis (1.25 mg/ kg)" on thyroid hormones as well as lipids profile and tested the effectiveness of two drugs one of them stimulates the hormones of the thyroid (
... Show MoreThe Wang-Ball polynomials operational matrices of the derivatives are used in this study to solve singular perturbed second-order differential equations (SPSODEs) with boundary conditions. Using the matrix of Wang-Ball polynomials, the main singular perturbation problem is converted into linear algebraic equation systems. The coefficients of the required approximate solution are obtained from the solution of this system. The residual correction approach was also used to improve an error, and the results were compared to other reported numerical methods. Several examples are used to illustrate both the reliability and usefulness of the Wang-Ball operational matrices. The Wang Ball approach has the ability to improve the outcomes by minimi
... Show MoreIn the present work experiments were conducted to study the effect of solid loading (1,5 and 9 vol.%) on the enhancement of carbon dioxide absorption in bubble column at various volumetric gas flow rate (0.75, 1 and 1.5 m3/h) and absorbent concentration (caustic soda)( 0.1,0.5 and 1 M ). Activated carbon and alumina oxide (Al2O3) are used as solid particles. The Danckwerts method was used to calculate interfacial area and individual mass transfer coefficients during absorption of carbon dioxide in a bubble column. The results show that the absorption rate was increased with increasing volumetric gas flow rate, caustic soda concentration and solid loading. Mass transfer coefficient and interfac
... Show MoreMany researchers consider Homogeneous Charge Compression Ignition (HCCI) engine mode as a promising alternative to combustion in Spark Ignition and Compression Ignition Engines. The HCCI engine runs on lean mixtures of fuel and air, and the combustion is produced from the fuel autoignition instead of ignited by a spark. This combustion mode was investigated in this paper. A variable compression ratio, spark ignition engine type TD110 was used in the experiments. The tested fuel was Iraqi conventional gasoline (ON=82).
The results showed that HCCI engine can run in very lean equivalence ratios. The brake specific fuel consumption was reduced about 28% compared with a spark ignition engine. The experimental tests showed that the em
... Show MoreThe experimental study showed the use of closed cavity wall (the thickness of the cavity 5cm) made a percentage reduction in the cooling load caused by heat gain from the wall by (21.5 %) compared with the conventional wall. also the thermal resistance of the closed cavity was an average (0.2 m2.oC/W).
The experimental results of the study showed that the use of closed cavity wall reduced the average temperature of the inner surface of the wall during the day, and that the reduction was an average (0.45 oC) when compared with the conventional wall , as well as the use of closed cavity wall reduced the temperature difference range of the inner surface of the wall during the day, and that the
... Show MoreThe performance and lifetime of the flexible asphalt pavement are mainly dependent on the interfacial bond strength between layer courses. To enhance the bond between layers, adhesive materials, such as tack coats, are used. The tack coat itself is a bituminous material, which is applied on an existing relatively non-absorbent surface to ensure a strong bond between the old and newly paved layer. The primary objective of this study was to evaluate the effects of various types of tack coat materials on interlayer bond strength and to determine the optimal application rate for each type. The tack coat types used in this paper were RC-70, RC-250, and CSS-1h. Both laboratory-prepared and field-constructed hot mix asphalt concrete pavements usin
... Show MoreA theoretical and protection study was conducted of the corrosion behavior of carbon steel surface with different concentrations of the derivative (Quinolin-2-one), namly (1-Amino-4,7-dimethyl-6-nitro-1H-quinolin-2-one (ADNQ2O)). Theoretically, Density Functional Theory (DFT) of B3LYP/ 6-311++G (2d, 2p) level was used to calculate the optimized geometry, physical properties and chemical inhibition parameters, with the local reactivity to predict both the reactive centers and to locate the possible sites of nucleophilic and electrophilic attacks, in vacuum, and in two solvents (DMSO and H2O), all at the equilibrium geometry. Experimentally, the inhibition efficiencies (%IE) in the saline solution (of 3.5%) NaCl were st
... Show MoreThis work is concerned with the study of the effect of cement types, particularly OPC and SRPC, which are the main cement types manufactured in Iraq. In addition, study the effect of mineral admixtures, which are HRM and SF on the resistance of high performance concrete (HPC) to internal sulphate attack. The HRM is used at (10%) and SF is used at (8 and 10)% as a partial replacement by weight of cement for both types. The percentages of sulphate investigated are (1,2 and 3)% by adding natural gypsum as a partial replacement by weight of fine aggregate. The tests carried out in this work are: compressive strength, flexural strength, ultrasonic pulse velocity, and density at the age of 7, 28, 90 and 120 days.
The r
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