KUFA JOURNAL OF ENGINEERING

This paper considers the practical application of nonlinear models in the analysis of Vierendeel truss. Results of some analyses performed using the reinforced concrete model of the general purpose finite element code ANSYS which had been obtained from previous works are presented and discussed. An incremental loading procedure is adopted following step by step nonlinear response. ANSYS program has the ability to use conventional Newton-Raphson (N-R), full (N-R) and modified (N-R) Procedure to perform the analysis process. The defaulted choice (program chosen) is used in this work which allows for automatically chosen of the most suitable method. Number of sub-steps for each case was changed until converged solution and full load deflection curve were obtained. Good agreement with the experimental tests of some previous studies was obtained using ANSYS solution. The maximum difference with the experimental test is found to be less than 10%. The effect of shear transfer coefficients of an open and a closed cracks are also studied. It was found that changing shear transfer coefficient of an open crack has more effect than changing of closed crack on the behavior of Vierendeel truss.

An analysis of mixed convection heat transfer inside a rectangular enclosure with side openings was numerically examined. The fluid enters the enclosure through an opening in the left vertical wall and exits from another opening placed in the right vertical wall. Two-dimensional Navier-Stockes equations are solved by using control volume based finite element technique .For mixed convection, the significant parameters are Grasfof number, Richrason number, and Reynolds number by which different fluid and heat transfer characteristics inside the enclosure are obtained. Streamlines, isotherms, average Nusselt number ,maximum temperature and other parameters of the heated wall are reported in the present study for Ri=0 to 10,Re=50,100,500,1000,Pr=0.7 to 100 and different aspect ratios. The computational results indicate that the heat transfer coefficient is strongly affected by Reynolds number and Richarson number. Higher Nusselt number is observed at large value of Pr. The comparison of the present results has been made are found in good agreement with known results.

Throughout urban and suburban areas, congestion at intersections going continuously to worsen, especially, in such high religious tourism cities like Najaf city. One potential treatment to combat congestion and safety problems at intersections is the Median U-Turn Intersection Treatment (MUTIT), which has been used worldwide extensively for many years and has been implemented successfully in recent years.

This paper summarizes the advantages and disadvantages of the MUTIT as alternative to conventional, un-signalized and signal-controlled intersections with left turns permitted. Furthermore, presents the design guidelines including the location and design of the median crossovers on the major roads. Many of the guidelines presented here are from the Michigan Department of Transportation (MDOT), and the 2004 AASHTO Green Book (AASHTO2004) The paper also takes three intersections in Najaf city in traffic volume counting, evaluation as intersection controls by roundabout once and by traffic signal in another, and discusses application criteria for the MUTIT, and presents how the performance of intersections, can be improved.

This study is devoted to investigate the behavior and performance of R.C. slabs strengthened with near surface mounted (NSM-CFRP). A system of computer program (ANSYS V.12.1) is used for analysis at this study. The ordinary reinforced concrete is modeled by 8-node isoparametric brick elements, while the steel reinforcing bars is modeled as axial members (bar elements) connecting opposite nodes in the brick elements with a full interaction assumption. The NSM CFRP strips were modeled by shell element. The effect of some selected parameters (thickness and shape) is studied. It is found that the ultimate load increased efficiently with increasing the thickness of NSM (87% & 123% for slabs S1 & S2 respectively). Concrete strength of R.C. slabs tested is (fc' 18.85). The maximum increment in terms of the slab load carrying capacity is limited by the concrete crushing.

Fuzzy Inference System appears a promising approach to address many important aspects of networks, particularly in allied fields of civil engineering. In this paper a Fuzzy Inference System for land soil erosion assessment was investigated.

The land soil erosion is controlled by multifarious parameters, such as slope, soil physical properties (texture, structure, permeability, etc.), rainfall, runoff, and crop cover.

The rainfall coefficient(R), slope coefficient (LS), soil erodibility factor (K), cropping system(C), and supporting practices (P) parameters are treated as antecedents and the land soil erosion (A) is the consequent. Developing the basis model using generalized Mamdani method based on data collected from available literature and assessment of the validity of the basic model depending on experimental data. The obtained results with Fuzzy Inference System are compared with experimental values and found remarkably close to each other values and found remarkably close to each other.

The effect of adding cempatch SBR ( Styrene- Butadiene – Rubber) emulsion to the following was studied: Cement mortar with different dosages of SBR ( 10 %, 25%, 35% ) by volume of water. Compressive strength of this mortar was tested at ages ( 7, 28, 60 ) days. Initial and final setting time were also recorded. SBR also added to concrete mix 1 : 2 : 4 with 0.45 water to cement ratio by weight, and SBR in dosages of ( 10 %, 2 5%, 35 % )by volume of water . Compressive strength in ages ( 7, 28, 60 ) days was tested, also absorption, slump loss with time and flexural strength were also measured. And SBR was also used as bonding mortar layer between old and new concrete layers, the compressive strength and flexural strength of bonded samples were tested. The results of adding SBR emulsion to cement mortar affects compressive strength negatively at all age. Initial and final setting time decrease with increasing the dosage of SBR. The using of SBR emulsion as admixture for concrete mix affects compressive strength negatively at early ages ( 7 days ) and positively at later ages. It also reduces; the absorption of concrete and slump loss with time and increase the flexural strength. The use of SBR as bonding layer showed increasing in compressive and flexural strength of the bonded samples compared with samples having old and new concrete without bond layer.

The turbulent flow friction of a water solution with a small amount of surfactant additive is dramatically reduced when compared to that of pure water. This effect offers a significant reduction in pumping power and energy consumption. Commercial implementation of drag reducing fluids have proved successful for oil pipeline transportation, district heating and cooling systems, fire fighting, sewer throughput, jet cutting, etc.

The investigation was carried out on a facility with a forced closed loop for pressure drop measurements. A type of anionic surfactant (Sodium dodecyl sulfate) mixed with same weight of counter ion material (Sodium nitrate) was used as a drag reducing additive to tap water at a mass concentration ranged from 50 to 2000 ppm. Pressure drop data was collected over a 1668 mm flow pipe of carbon steel with 15.8 and 26.6 mm internal diameter and different solution flow rate (up to 8 m3/h) at constant temperature of 30 ÌŠC (ambient temperature).

The paper focused on calculation of friction factor from experimental data. It was found that the friction factor values lies near Blasuis asymptote for pure solvent, while they positioned towards maximum drag reduction asymptotes when surfactant is added. A maximum drag reduction percent of about 66% was obtained by using 2000 ppm surfactant – counter ion aqueous solution. Also, it was concluded that there is a critical Reynolds number equals to about 96000 not to be exceeded because any further increasing leads to decrease in drag reduction. In addition, a correlation equation was found to correlate wall shear stress as a function of bulk mean fluid velocity. This correlation equation is of value in scale up of results obtained in small laboratory equipments to larger diameter pipes and different operating conditions. Another objective was to investigate the mechanism behind a possible drag reduction.

Sensor fault detection is carried out based on the characteristics of the soft computing techniques; neural network and adaptive neural fuzzy inference system ANFIS. In this paper, a neural network (non-model based technique) and ANFIS has been used for detection and isolation of temperature sensor fault TMP36. The measured states are then compared with true estimated states and if their difference exceeds threshold value, the particular sensor measurement is ignored and replaced by the true estimated state. Residual generation is an essential part of model-based fault detection schemes. This paper develops and implements neural-network and ANFIS based system identification techniques for nonlinear systems with the specific goal of residual generation for fault detection purposes. The two approaches are tested on a temperature sensor model. Performance comparisons of the two neural network and ANFIS are presented.

Strength and Durability of fiber reinforced polymer composites (FRP) are controlled by the durability of their constituents: reinforcement fibers, resin matrices, and the status of interfaces. A great deal of research has been focused on the relationship of fibers with matrix, on the other hand, the diameter of the fiber and properties of fiber-matrix composites. The present investigation aims to study the effects of adding steel woven fibers to polymer (polyethylene) on some mechanical properties for resulting composite materials.

This research tries to study the using of metal woven fibers as a reinforcement Material with Matrix from polyethylene grades (LDPE,LLDPE) as a composite material that was prepared using an injection molding process at 180- 200 Co and 60 rpm with different diameter (0.25- 1.0 mm).the results show that the tensile strength will slightly increase with percentage about (9%-18%) for the LLDPE and LDPE polymer composite respectively, and tensile modulus will significant increase about (80%- 190%) with woven metal fibers .The ductility is decrease with 68% for LDPE but it was 78% for LLDPE . The flexural strength will decrease with percentage about (36%-22%) for the LLDPE and LDPE polymer composite and impact strength with percentage about (78%-68%) and impact strength about (47%-40%) for the LLDPE and LDPE polymer composite respectively

This paper studies the effect of different ratios of clay addition on the concrete properties. Most of the standards limit the ratio of the clay in aggregates due to its harmful effect on the concrete properties. For example, ASTM C33 limits the fine contents in fine aggregate to 5% whereas the ratio of clay lumps is limited to 0.5% as deleterious substances included in the fine materials as very fine substances .This study has considered many ratios of clay addition(0%,2%,3%,4% and 5%) of the total aggregate weight to the concrete mixes and observed the governed values of compressive strengths and workability. A series of cube groups were fabricated with different water-cement ratios (0.45,0.5 and 0.55) and different mix ratios(1:1:2,1:1.5:3 and 1:2:4).It is seen that as the ratio of clay increases, slump decreases; therefore, more water will be needed to reach a reasonable workability while the compressive strength is severely affected in high ratios of clay existence. There is no effect of age on the ratio of strength decrease when a high ratio of clay is added or existed. The strength will decrease by about 33% if a 5% of clay is available in fine material. This study has come as a result of investigating the reasons behind the continuous deterioration in concrete cubes that came to the laboratory for the aim of testing through local construction companies and contractors who are working in most of projects all over the middle region governorates in Iraq.