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Go to Editorial ManagerIn this paper, computation fluid dynamics model (CFD) is used to simulate a turbulence flow fields along the jet ejector. A Steady-state 2-D compressible flow model utilities the standard k- turbulent model has been used. The performance of jet ejector is simulated by FLUENT 6.3 (code) and GAMBIT software, using finite-volume scheme to solve transport NAVIER STOKE equations. The objective of this study is to investigate the high- performance of jet ejector geometry (mass flow and head ratio) nozzle to throat diameter at eight cases (DN/DT) with different initial pressure. Research is performed to optimize jet performance by varying initial pressure and nozzle diameter ratios from (1/8) to (8/8). To increase understanding of the axial velocity distribution at an important regions along the ejector, three regions are chosen, at inlet (1,3), nozzle exit(2) and midpoint of throat(4), with an important different diameters ratio cases 1,2,3,5,7 and 8 respectivly. The comparison of these results is presented by the axial velocity magnitude, mass and head ratio of the ejector at the above cases. Results show that higher pressure ratio and mass ratio (high performance) occur when the nozzle to throat diameter ratio (DN/DT) was (5/8) and (1/8) respectively. Also mass ratio is decreased at all initial pressure when the diameter ratio increased.
In this research, a two – dimensional numerical investigation is conducted to show the ability of the jet-ejector to prepare the air – methane mixture at different equivalence ratio. The basic dimensions (diameters ratio, throat length, angle α , and angle θ ) of the jet-ejector are taken into account on calculating the equivalence ratio. The results showed that the ratio of the diameters has a higher effect than other parameters on preparing a mixture for equivalent ratios including both rich and lean mixture. The rest of the factors did not have a significant effect on the value of the equivalence ratio, and only had a role in preparing an equivalence ratio for rich mixture type.
Parallel flow microchannel heat exchanger performance was numerically investigated, for laminar, 3-D, incompressible and steady state flow with slip flow and temperature jump conditions. The continuity, Navier-Stokes equations and the energy equations for the hot and cold fluids were solved by using finite volumes method and SIMPLE algorithm method with FORTRAN code to obtain the velocity and temperature distributions for the two fluids and the separated wall between them. The main investigation parameter that affected on the performance and effectiveness of heat exchanger are: Reynolds number Re, thermal conductivity ratio Kr, Knudsen number Kn, thickness of separating wall, heat capacity ratio Cr and aspect ratio α. Increasing of Reynolds number, Knudsen number, thickness of separating wall, heat capacity ratio and aspect ratio each separately leads to decrease the effectiveness while increasing of thermal conductivity ratio up to 10 leads to increase the effectiveness. Also, it is found that friction number and Nusselt number both decreases with increasing Knudsen number.
This work uses different shapes of intake manifold for study the effect on a single cylinder four stroke gasoline engine. A numerical simulation of the flow achieved through five intake manifold designs, using 3D Computational Fluid Dynamic (CFD) software package FLUINT (6.3.). Accordingly, the three-dimensional resolution of Navier-Stokes equations in conjunction with the standard k-ε turbulence model is undertaken to provide knowledge of the air movement nature and examining the intake manifold optimal geometry. Five cases of intake manifold are examined experimentally in order to produce a comprehensive and realistic data set. These data are in the form of engine performance, exhaust gas products and relative AFR for each case separately under different engine speeds. Exhaust gas analyzer type (Infragas-209) is used in the present work to measure exhaust gas concentrations and relative air/fuel ratio ( ). The results were obtained in this investigation showed that a Simulate numerically and experimentally is capable to select the optimized intake system geometry with reliability. Velocity is highest near the outer wall at increased the curvature ratio and pressure is highest near the inner wall at increased the curvature ratio. The secondary flow increases when the engine speeds and curvature ratio increase because of increasing the pressure difference between the inner wall and the outer wall. The effect of these parameters explained on the swirl air movement and tumble inside the cylinder are increasing by increase the engine speed and γ respectively. The increasing in the engine speed and the optimum selection of the manifold which designed enhanced the mixing of the fuel with air. The results showed that the optimized manifold 135º- NE (case 5) due to enhance AFR, fuel consumption and exhaust emissions are improved.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
The flow control around the airfoil is widely investigated and utilized in the aircraft industry. The benefit of reducing the separation effect and its impact on the aerodynamic performance made the effort on this area is more desirable as this will impact to enhance the flight control as well as to reduce the fuel consumption during the flight. In this paper, the flow control using leading-edge blowing technique has been conducted for NACA0018 airfoil at Reynolds number 6.85 and 13.7 × 10 5 . A CFD analysis has been conducted to examine several flight parameters and blowing speed to explore the benefit of using the blowing in this wing section. The results indicate that the lift coefficient can be enhanced to be increased by 4-6% as compared with no blowing case. However, this increase ratio is affected by the operational Reynolds number and blowing ratio. Higher speed means less benefit from blowing within the limit of blowing ratio of 1. The benefit of using the blowing could come with an increase in the drag at some angle of attack. It is noticed that the blowing technique can generate positive pitching moment at lower angle of attack and can reduce the negative moment when the separation is happening at higher angle of attack. Also, the lesson learned in this paper is that the blowing benefit is more pronounced when the flight is under low Reynolds number environment.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
This study investigates the effect of the shear span-to-effective depth ratio (a/d) on the behavior of high-strength steel fiber–reinforced concrete deep beams without stirrups containing circular web openings. A circular opening of 12.6 cm diameter was positioned at the center of the shear span, and beam performance was evaluated in terms of crack patterns, load–deflection response, and stress–strain behavior. Four specimens were tested experimentally. The control specimen consisted of a solid deep beam without openings and without steel fibers, while the remaining three specimens were reinforced with 1% steel fibers and included circular openings. All specimens were reinforced with 2Ø12 mm top bars, 3Ø16 mm bottom bars, and two stirrups at the supports to prevent local failure. The beams had different shear span ratios (a/d = 0.75, 1.0, and 1.5) and corresponding total lengths of 1025 mm, 1200 mm, and 1550 mm, respectively. All specimens were simply supported and subjected to two-point loading. The experimental results revealed that the optimal shear span ratio for maximum performance was a/d = 0.75 when combined with 1% steel fiber reinforcement. In addition, the ultimate strength of beams with circular openings decreased as a/d increased, with a strength increase of approximately 5.48% at a/d = 0.75 compared with a/d = 1.0.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Due to the wide use of rubber components in different engineering applications such as vibration isolators, engine mounts, car tires, and bridge bearing pads, etc. This rubber component mostly subjected to high levels of vibration and noise which are among the most reasons that lead to the failure of the structures. In the present paper has been performed experimentally to investigate the influences: different content ratios of natural rubber (NR) and polybutadiene (BR.cis) rubber blends [1: (50/50) %, 2: (60/40) %, 3: (70/30) %, 4: (80/20) %, 5: (90/10) %, 6: (100/0) % pphr], and two carbon blacks types (N375, and N220) on the dynamic properties (Rebound Resilience, Damping Time, and Decay Rate). The experimental results showed that the rubber compound that has the blending ratio [1: (50/50) %] has high resilience (low damping), high damping time and high displacement for two carbon black types used in this work. While these properties were improved whenever the rubber blend close to the percentage [5: (90/10) %]. The damping time, amplitude, and resilience of a rubber compound with a blending (90/10) % and carbon black (N220) are decreased by (24.53 %, 36.854 %, and 36.852 %), respectively, compared with a rubber blend that has the blending ratio of (50/50) %.
In this study a two dimensional, steady state propagation of the laminar premixed flame was numerically and experimental are investigated. The energy, momentum, continuity equations for species and global reaction mechanism with equation of stat for ideal gases were solved. Constant temperature boundary condition is applied on axi – symmetric in y – direction domain. The governing equations were discretized by using computation fluid dynamics (CFD) and finite-volume method - central differencing scheme, then solved using Gauss-Seidel Iteration method on uniformed grid with VISUAL BASIC code. Effects of equivalence ratio and initial temperature of fresh gases (air – fuel mixture) were investigated for three types of fuel Methane, Propane and Butane. Also the flame speed and flame temperature were experimentally measured for air – fuel (Methane, Propane, Butane and LPG) mixtures. The burning velocity was calculated depending on the flame speed and flame temperature measuring. The flame speed and flame temperature were measured by using optical technique. Effects of equivalence ratio and initial temperature of fresh gases (air – fuel mixtures) on flame speed and flame temperature are investigated experimentally. Results were generated for the detailed description of the local fluid flow and heat transfer characteristics including temperature, axial velocity, density and mole fractions profiles. For example the flame speed reached 274.4 cm/s as a maximum value at Ø=1.1 for propane air mixture, and flame temperature comparison give a good agreement between theoretical and experimental results at rich mixtyre
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Several geometrical elements influence the aerodynamic properties of the Darrieus vertical axis wind turbines (VAWTs). Many extant studies have examined properties, such as solidity, pitching axis position ( x /c), length of chord (c), blade quantity (N), diameter (d) of the rotor, and aspect ratio. However, not many have examined the shape of the airfoil (AF), which is a vital property that remains to be thoroughly investigated. Therefore, this present study used computational fluid dynamics (CFD) to investigate many airfoils blade characteristics, such as blade thickness (BT), maximum camber ratio (MCR), MCR location (MCRL), and air speed (AS), to determine their impact on VAWT performance. The results demonstrate a blade thickness BT of 10 to 12%, MCR of 0 to 22%, and MCRL of 24 to 23% yield a comparatively high coefficient of power, adequate optimal blade rotation to airspeed ratio (TSR), broader operational area, and high band efficiency while air velocities of 15 to 10% yield a comparatively higher power coefficient.
The paper presents an experimental and theoretical study on the behavior of circular concrete filled aluminum tubular columns. The main purpose of the experimental program was to investigate the structural behavior of aluminum-concrete composite columns under axial compression loading conditions. Twenty four specimens were tested to investigate the effect of diameter, D/t ratio and slenderness ratio of a aluminum tube on the load carrying capacity of the concrete filled tubular columns. Diameter to wall thickness ratio ranged between 11.9 ≤ D/t ≤ 22.8, and the length to tube diameter ratios of 3 ≤ L/D ≤ 10 were investigated. The main purpose of the theoretical investigation was to predict the strength of aluminum -concrete composite columns subjected to axial compression loading conditions. The empirical equations proposed in the present study are capable of predicting the values of ultimate loads of aluminum -concrete composite columns and were in good agreement with the experimental values. The average values of ratios of experimental to predicted values of ultimate loads are 1.0104 for the proposed empirical equations. The circular hollow section tubes were fabricated by extrusion using 6061-T6 heat-treated aluminum alloy. The column strengths, load-axial shortening relationship and failure modes of columns were presented.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
Experimental investigation was conducted on low speed wind tunnel with (50 mm x100 mm) rectangular working section. Five smooth circular cylinders, as bluff bodies were applied. Cylinders diameters are 12.5, 15, 17, 35, and 37 mm which experience blockage ratio of 12.5%, 15%, 17%, 35%, and 37%, respectively. The range of Reynolds No. and air velocity for present study is 0.7x10^4-5x10^4 and 10-20 m/s respectively which are more applicable in engineering field. The experiments were carried out in fluid mechanics laboratory, Faculty of engineering and technology, Sebha University, Libya. Results indicate that cylinders of blockage ratio of 35% and 37% experience lower pressure coefficients around bodies, lower velocity distribution in the wake, and higher drag coefficients. Drag coefficient correction is agreed with unconfined flow for blockage ratio less than 17%. Wake and buoyancy blockages may have effect on models of higher blockage ratios.
This study aims to evaluate quality of groundwater samples in south of Basrah Province for industrial, construction and agricultural purposes. Groundwater samples were collected in summer season of the year 2015 from (29) wells located in different districts in Basrah province (Safwan, Zubair and Um- Qasir). The groundwater samples were analyzed for pH, electrical conductivity (EC), total dissolved solids (TDS) and other major ions. The chemical results indicate that the groundwater in the study area was unsuitable for industrial uses according to standard classification. Some other standard classification recommended that, the unsuitable groundwater could be used after treatment of some of its element while groundwater in study area may be used for construction purposes with suitable treatment of high ions concentration. After studying the factors that determine the suitability of groundwater for irrigation purpose such as pH, electrical conductivity, total dissolved solids, Sodium ratio(Na%) and sodium adsorption ratio (SAR). The groundwater in study area can be classify based on (EC) values, as unacceptable for irrigation except for very salt-tolerant plants and excellent drainage. According to other parameters like Na% and SAR , groundwater of the study area are classify as poor to very poor water and need for suitable treatment before using it.
The effect of fouling due to scale formation of pre-heater tubes on the thermal performance of Reticulating multi stage flash Distillation plant performance ratio and the increase of the ratio of Makeup water to the product Quantity for a 5MGPD recirculating System has been prediction The results appeared That eth Effect of scale formation is more Effected as the Maximum brine temperature decrease.
In this work, the efficiency of double Gauss quadrature method, used to integrate over a rectangular element in 3D BEM, has been investigated. The efficiency of a quadrature or integration scheme is investigated by estimating the critical ratio for which the absolute relative error of the numerical integration is less than $1\times10^{-6}$. As small as the critical ratio is, the quadrature is more efficient. Also, special transformation techniques have been introduced and used to increase the accuracy and efficiency of double Gauss quadrature especially for near singular cases, where the source point is very close to the element under consideration. Three types of kernels were considered, weak, strong and hyper singular kernels which can be encountered in the integral equation of 3D elastodynamics BEM problems.
Continuously Variable Transmission (CVT) combines the efficiency of manual transmissions with the driving comfort of automatic transmissions while providing an infinite range of gear ratios, improved fuel economy, and enhanced acceleration performance. This study presents a comparative evaluation of CVT performance against manual and automatic transmissions in a parallel hybrid electric vehicle (HEV), focusing on fuel consumption and exhaust emissions. A baseline HEV model equipped with a CVT gearbox was selected from ADVISOR simulation software and subsequently modified by replacing the CVT with manual and automatic transmissions for comparison. Exhaust emissions, including catalytic converter pollutant reactions, were recorded for all configurations. Performance assessments were conducted using several global standard driving cycles to simulate real driving conditions. Results indicated that the CVT configuration achieved superior fuel economy and a significant reduction in exhaust emissions compared with manual and automatic transmissions. This improvement is attributed to the CVT’s effective control of speed ratio and overall transmission efficiency. The findings support the suitability of CVT gearboxes for urban hybrid vehicle applications due to their low fuel consumption and high efficiency in speed ratio control.
Fluidized bed reactor (FBR) is an attached growth system used mainly for biological treatment of industrial wastewater of high organic content. These wastewaters are usually resulted from refineries and milk, starch, and olive oil industries. The objective of this study is to investigate the use of fluidized bed reactor for treating sanitary sewage. The study was accomplished using a pilot plant of the FBR. The pilot plant was constructed and installed in Hamdan Sewage Treatment Plant in Basrah governorate. That was to maintain continuous source of settled sewage which is the influent to the FBR. The period of plant operation was nine weeks. During, this period, the plant was operated at three phases of different conditions (up flow velocity and recirculation ratio). To study the performance of FBR, the main measured parameters were; BOD, DO, VSS, pH, and temperature. The most important conclusions of this study are; (1) the maximum efficiency of BOD removal is 78.6% which was obtained for hydraulic retention time (HRT) of 24min and upflow velocity of 1.59m/min, (2) the effluent BOD values during phases-1 and 2 of plant operation match that of stabilization ponds and trickling filters and during phase-3 matches that activated sludge process, (3) during all operation phases, the values of effluent pH are within the limits specified in national standards of secondary effluents, (4) as F/M increases, the efficiency of BOD removal decreases and the maximum efficiency of BOD removal (78.6%) was obtained at F/M ratio equals 23.47 day -1 , and (5) the HRT of fluidized bed reactor is on order of minutes, while, the values of HRT of activated sludge systems and stabilization ponds are on order of hours and days, respectively.
In this paper friction stir welding process has been studied whereby utilized FEM method (Ansys software ver. 20). The main effective parameter in this process were rotational speed, linear speed, tool shoulder radius, heat transfer coefficient and clamping percentage to study their influence on represent temperature, von misses stress and frictional stress distribution. Because of the difficulty to obtained the number of the simulation cases in order to get the most important results, Taguchi L27 orthogonal array was apply to reduce the total number of the simulation cases. Pure copper (t = 3.18 mm) material type was applied as work plate material. ANOVA statistical tool was utilized to achieved the optimization process after the simulation cases done. Percentage of contribution of each parameter can be obtained by ANOVA table and mean of S/N ratio plot. Validation process was achieved between the Current study and experiment work in the temperature distribution field with percentage of error 2.7 %. From optimization result It is found that the optimum condition in order to obtained good results for temperature was rotational speed of (450 rpm), linear speed (2.75 mm/s), tool shoulder radius (7 mm), heat transfer coefficient (300 w/m 2 K), clamping distance percentage (40 %). And for von misses stress was rotational speed of (550 rpm), linear speed (3 mm/s), tool shoulder radius (7 mm), heat transfer coefficient (300 w/m 2 K), clamping distance percentage (20 %). While for frictional stress was rotational speed of (450 rpm), linear speed (2.5 mm/s), tool shoulder radius (7 mm), heat transfer coefficient (300 w/m 2 K), clamping distance percentage (30 %).
The conjugate natural convection-conduction heat transfer in a domain composed of nanofluids filled porous cavity heated by a vertical solid wall is studied under steady-state conditions. The vertical left wall of the solid is kept isothermal at hot temperature Th. The vertical right wall of the solid is in contact with the nanofluid saturated porous medium contained in the cavity. The right vertical wall of the cavity is kept isothermally at the lower temperature Tc. The upper and lower horizontal walls are kept adiabatic. The governing equations of the heat transfer in the solid wall and heat and nanofluid flow, based on the Darcy model, in the nanofluid-saturated porous medium together with the derived relation of the interface temperature are solved numerically using the over-successive relaxation finite- difference method. A temperature independent nanofluids properties model is adopted. The investigated parameters are the nanoparticles volume fraction (0-0.2), Rayleigh number Ra (10-1000), solid wall to base-fluid saturated porous medium thermal conductivity ratio kwf (0.1, 1, 10), and the solid wall thickness D (0.05-0.5). The results are presented in the conventional form; contours of streamlines and isotherms and the average Nusselt number. At a very low Rayleigh number Ra=10, an enhancement in heat transfer within the porous cavity with is observed. Otherwise, the heat transfer may be unchanged or deteriorated with depending on the wall thickness D and the conductivity ratio kwf.
This paper demonstrates experimental and numerical studies to investigate in perforation pipes with a phasing 180° and perforation densities 9 spm in a horizontal wellbore. The experimental study was conducted to investigate the phasing angle 180° in a horizontal wellbore. The wellbore has an inner diameter of 44 mm, as well as the length of the pipe is 2 m. For this purpose, a simulation model was created in the wellbore using the ANSYS FLUENT simulation software by using the standard k - e model and applied to the (CFD) with changing the axial flow from (40 - 160) lit/min and constant inflow through perforations from range (20 - 80) lit/min. Concerning the findings of this study, it was noticed that the total pressure drop (friction, acceleration, mixing) goes high as the total flow rate ratio increases. As well as, an increase of the inflow concerning the main flow rate ratio leads to an increase in the total pressure drop and a decrease in the productivity index. Furthermore, the percentage error of the total pressure drop between the numerical and experimental results in test 4 is about 5.4 %. Also, the average velocity goes high with increasing the total flow rates and the velocity keeps increasing along the length of the pipe until it reaches its maximum value at the end of the pipe due to the effect of the perforations. It was concluded that there are the numerical and experimental results reflected a good agreement concerning the study of the flow-through perforations at 180° angle in terms of pressure drop and apparent friction factor, etc.
In this research ,the sediment load in Shat Al- Gharaf River , lies in the south of Iraq ,has been studied . Two empirical formulas those have been presented by ; Bagnold and Van Rijin were adopted as a deterministic equations for computing the sediment discharge in selected reaches of river . The application of these equations requires to do different hydraulic , sediment , and geometric measurements for the selected reaches . Accordingly , thirteen sections along the river within a study area have been adopted . After analyzing the available data , a new formula for estimating the suspended sediment load in Shat Al-Gharaf was developed , depending on the data for ten sections of this river and by using SPSS program , the determination coefficient of the new formula was (R 2 =0.94) . The validity of the established formula has been verified using some well related (i.e., nearly the same hydraulics and geometrical circumstances) of field data over the world was selected from published literatures [8] these are : Colorado river data of the U.S.B.R.(1958) ,River data from Leopold (1969) , and India canal data of Chaudry et.al.(1970). As well as ,those observed in the remaining three sections of present river , the verification shows a good agreement . The results of the adopted two formulas and the new formula were compared with field measurements using Discrepancy Ratio (bais) method . The suggested new formula gave the best results where 50% of data located within a discrepancy ratio close to one and 30% of data located within an error ±20% , that is refer to suitability adoption this formula as a deterministic equation to estimate the sediment load in Shat Al-Garaf river within a study reach .
In this study, a numerical investigation has been carried out for single phase flow behavior for thirty six internally finned tubes to demonstrate the effect of axial pitch to fin height ratio (p/e) for 0.8≤p/e≤6.345, helix angle of internal fins (β) for 30°≤β≤70°, apex angle of internal fins (α) for 0°≤α≤53.13°, internal fin height (e) for 0.6mm≤e≤1.0mm, internal tube diameter (di) with 14 mm and Reynolds number (Re) of single phase flow for 10000≤Re≤50000 on enhancement of forced convection heat transfer and reduction of friction factor by using ANSYS CFX program. It solves the three- dimensional Navier-Stokes equations for steady state turbulent with SST model and enhance wall treatment. The numerical analysis provided at fully developed velocity and temperature. Numerical results showed that the smallest axial pitch to fin height ratio (p/e) =0.8 and with apex angle α=10 degree provided enhancement of heat transfer of 2.8 to 3.55 times higher than of smooth tube. Finally, present numerical results are seen to be in good agreement with literature experimental correlations.
In this study, a numerical investigation has been carried out for single phase flow behavior for thirty six internally finned tubes to demonstrate the effect of axial pitch to fin height ratio (p/e) for 0.8≤p/e≤6.345, helix angle of internal fins (β) for 30°≤β≤70°, apex angle of internal fins (α) for 0°≤α≤53.13°, internal fin height (e) for 0.6mm≤e≤1.0mm, internal tube diameter (di) with 14 mm and Reynolds number (Re) of single phase flow for 10000≤Re≤50000 on enhancement of forced convection heat transfer and reduction of friction factor by using ANSYS CFX program. It solves the three-dimensional Navier-Stokes equations for steady state turbulent with SST model and enhance wall treatment. The numerical analysis provided at fully developed velocity and temperature. Numerical results showed that the smallest axial pitch to fin height ratio (p/e) =0.8 and with apex angle α=10 degree provided enhancement of heat transfer of 2.8 to 3.55 times higher than of smooth tube. Finally, present numerical results are seen to be in good agreement with literature experimental correlations.
In this paper, a new model of beam was built to study and simulate the buckling behavior of function graded beam. All equations of motion are derived using the principal of the minimum total potential energy and based on Euler-Bernoulli, first and high order shear deformation Timoshenko beam theory. The Navier solution is used for simply supported beam, and exact formulas found for buckling load. The properties of material of FG beam are assumed to change in thickness direction by using the power law formula. The dimensionless critical buckling load is calculated analytically by the FORTRAN program and numerically by ANSYS software. In the beginning, the analytical and numerical results are validated with results available in previous works and it is also has very good agreement in comparison with and some researchers. In the present study, the lower layer of the graded beam is made up of aluminum metal. As for the properties of the rest of the layers, they are calculated based on the modulus ratios studied. The effect of length to thickness ratio, modulus ratio, and power law index on the dimensionless critical buckling load of function graded beam calculating by FORTRAN and ANSYS programs are discussed. The numerical analysis of function graded beam offers accurate results and very close to the analytical solution using Timoshenko Beam theory.
This study investigates the shear strength behavior of two-layer reinforced concrete beams consisting of two different types of concrete. One of the layers made of lightweight concrete (LWC) and the other was normal weight concrete (NWC). A total of 16 shear deficient reinforced concrete beams were fabricated and cast with NWC, LWC, and two-layer beam of both material with different configuration. All the beams were tested under four-point loading after 28 days. The variables of the experimental program include the ratio of thickness of the lightweight concrete layer to the overall depth of beam ( h LW / h ), and concrete compressive strength. Experimental results which include load-deflection response curves along with failure modes for NWC, LWC and two-layer beams. The results showed that all beams failed in a similar mode, due to diagonal tension shear crack. Based on the experimental results it can be also concluded that the shear load is governed by compressive strength of lower layer of the concrete when the shear span to overall depth ( a / h ) of the beams is 2.75 or more. While for the a / h 2.375 and 2.00 the two-layer beam has a significant reduction in the shear capacity compared to the NWC beams and increasing compared to LWC beam. The ratio of experimental shear stress divided by the root square of concrete compressive strength (vexp √f c ' ) , which demonstrates the diagonally cracked concrete's ability to transfer strain and shear was maintained for all configurations greater than 0.17, which is the minimal value recommended by ACI318-19.
Orthogonal frequency division multiplexing (OFDM) has become a popular modulation method in high-speed wireless communication systems due to its high data rate transmission capability and robustness against multipath fading effects. One of the major drawbacks of OFDM at the transmitter side is the high peak-to-avenge power ratio (PAPR) of the OFJ)M signal. In this paper, an algorithm is proposed to reduce the peak-to-average power ratio of OFDM signal with a large number of sub-carriers. This algorithm is based on the tone reservation method. The computer simulation tests show that the suggested algorithm reduces the PAPR to a factor of S.2S dB and needs less number of iterations as compared with the traditional tone reservation algorithm.
In this study, a numerical investigation has been carried out for single phase flow behavior for thirty six internally finned tubes to demonstrate the effect of axial pitch to fin height ratio (p/e) for 0.8≤p/e≤6.345, helix angle of internal fins (β) for 30°≤β≤70°, apex angle of internal fins (α) for 0°≤α≤53.13°, internal fin height (e) for 0.6mm≤e≤1.0mm, internal tube diameter (di) with 14 mm and Reynolds number (Re) of single phase flow for 10000≤Re≤50000 on enhancement of forced convection heat transfer and reduction of friction factor by using ANSYS CFX program. It solves the three- dimensional Navier-Stokes equations for steady state turbulent with SST model and enhance wall treatment. The numerical analysis provided at fully developed velocity and temperature. Numerical results showed that the smallest axial pitch to fin height ratio (p/e) =0.8 and with apex angle α=10 degree provided enhancement of heat transfer of 2.8 to 3.55 times higher than of smooth tube. Finally, present numerical results are seen to be in good agreement with literature experimental correlations.
The reason for the widespread use of steel box girders is that they have high structural efficiency due to the high bending, high torsional stiffness and rapid erection. For bottom flange of the girders, the buckling behavior during production and erection due to compression strength can be a problem. The compression plate with longitudinal stiffeners typically renders an economic. The optimal design of longitudinal stiffeners is discussed. The results are based on 3-D FEA (ANSYS19.2) of many stiffened compression bottom flange models, the moment of inertia requirement of bottom flange longitudinal stiffener is investigated by studying the effect of many parameters as longitudinal stiffeners numbers, stiffener sections, plate aspect ratio and compression flange thickness. Also, the stiffeners effect on the compression panel plate stresses were studied by modeling girder with and without longitudinal stiffeners. The finite element method is useful as they can be used to study the plate with stiffeners in an economical way, and we don’t need experimental and laboratory tests.
This research is devoted to investigate the effect of Carbon Fibre Reinforced Polymer (CFRP) strips on the behaviour and load carrying capacity of strengthened and repaired reinforced concrete corbels. Experimental investigation were carried. The experimental program variables include location, direction, amount of CFRP strips and effect of shear span to effective depth (a/d) ratio on the behaviour of strengthened corbels. All corbels had the same dimensions and flexural reinforcement and they were without horizontal shear steel reinforcement. The experimental results obtained from the adopted strengthening and repairing CFRP techniques showed a significant improvement in the behaviour and carrying capacity of the tested corbels. An increase of about (44.5 - 60) % in the ultimate load has been obtained for specimens strengthening by inclined technique compared to the ultimate load of control corbel and (14.7 - 31.2)% for specimens strengthening horizontal technique. For corbels repaired with CFRP strips, an increase of (56%) with respect to the ultimate load of control corbel is achieved. Also the strengthened corbels show stiffer load deflection response than corresponding control corbels (unstrengthened corbels).
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
This study is to investigate the effect of partially replacement of coarse aggregate by waste plastic and using the paper sludge as additive material at concrete, on the hardened concrete properties and its impact on structural behavior of the reinforced concrete members (slab, column, and beam). Plastics and paper are widely used in daily life in huge amounts. Both incineration and landfilling are options for disposing of plastic and paper waste, but either one could be harmful to the environment. Therefore, reducing waste or increasing its value can reduce pollution and reduce disposal costs. The variables of the experimental program include the ratio of waste plastic and paper sludge, the used ratios for plastic and paper were (5%, 10%, and 15%) by volume. Hardened concrete properties were investigated for concrete include: flexural strength, modulus of elasticity, and splitting tensile strength. For each structural reinforced member, the (Load – Deflection) curve has been extracted. The study shows that the plastic waste negatively affects most of concrete properties. The research indicates that using waste plastic in reinforced concrete members with percentage of (5% and 10%) by volume as a partially replacement of coarse aggregate giving acceptable results. However, when adding (5%) by mixture volume of waste paper in reinforced concrete members, the load-deflection behavior and ultimate load-bearing capacity have been improved. In general, using waste plastic and paper sludge in concrete mixtures lead to reduction in ultimate load ranging between (4.62%-10.82%) for slab under point load, (4.85-18.99%) slab under distributed load, (3.72%-12.21%) column, and (1.78%-7.16%) beam specimens respectively.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
In this study, glass-filled epoxy functionally graded material (FGM) was prepared by adopting the hand lay-up method. The vertical gravity casting was used to produce a continuous variation in elastic properties. A 30 % volume fraction of glass ingredients that have mean diameter 90 µm was spread in epoxy resin ( ρ = 1050 kg/m 3 ). The mechanical properties of FGM were evaluated according to ASTM D638. Experimental results showed that a gradually relationship between Young’s modulus and volume fraction of glass particles, where the value of Young’s modulus at high concentration of glass particles was greater than that at low concentration, while the value of Poisson’s ratio at high concentration of glass particles was lower than that at low concentration. The manufacture of this FG beam is particularly important and useful in order to benefit from it in the field of various fracture tests under dynamic or cyclic loads.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
In this paper, a compact ultra-wide band (UWB) printed patch antenna is designed and optimized using four biologically and plant inspired optimization algorithms. These algorithms are the newly adopted Moss Rose Optimization Algorithm (MROA), Runner Root Algorithm (RRA), Sunflower Optimization Algorithm (SFOA) and Particle Swarm Optimization (PSO). These algorithms are modified in an optimizer software, which merges the attributes of the design of electromagnetic environment of CST Microwave Studio with those of the technical programming environment of MATLAB. A compact (12 × 21.5) mm 2 printed patch antenna has been proposed and simulated over the whole UWB frequency range using these four optimization algorithms. The simulation results show the superiority of the antenna design using MROA, which has the widest covered frequency range, the lowest reflection coefficient and the lowest standing wave ratio.
The natural convection heat transfer from horizontal isothermal three cylindrical rods inside equilateral triangular enclosure has been studied numerically. The enclosure is filled with air, and the heated rods are located at equal distances (E) from triangle center. A finite element software package (FLEXPDE) is used in the present study to solve the set of non-linear equations governing the process. Solutions are obtained for aspect ratio D/H=1/6 and range of distance E=0.2-0.6 and Rayleigh (Ra) number changes from 103 to 106. The effect of Ra and E were examined. Results are presented by streamlines, isotherms and Nusselt number and it indicates that the Nusselt number is significantly increase with increasing both Ra and E. A comparison of the Nusselt number was made with that obtained by [7], and showed substantial improvement to about 65% in some cases.
In digital signal processing (DSP), FIR digital filter is very important device to deal with particular frequencies of a certain signal to be appropriate for some applications such as communications, sound equalizers, etc. In this paper, FIR filters are adopted to decompose the original sound signal into four signals. Each one is created by one FIR filter and each filter represents a narrow band of frequencies. The filter output is used to drive a certain variable speed drive (VSD) to control the speed of a water pump and light intensity of a colored lamp. This filter output signal is applied to the analog control voltage terminals of the VSD unit to control the frequency and magnitude of the voltage supplied to the lamp and pump. Thus, the heads of the water jets and the light intensity are controlled according to the analog control signals which are created by the FIR filters (The VSD is used to map the filter output into light intensity and water head by controlling the supplied voltage of them). The goal of this study is to design and simulate four sound harmonics bands produced by FIR filters to drive four VSDs which are simulated using V/F ratio constant method for musical fountain operation.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
This paper presented experimental and numerical studies to investigate pressure drop in perforation horizontal wellbore with a 90° phasing and 20 spm perforation density. The experimental apparatus has been constructed to calculate the static pressure drop and calculate the exit velocity in the horizontal pipe after mixing the axial flow with the radial flow through the perforations in the wellbore. The specifications of the wellbore used were the inner diameter is 44 mm, length is 2 m, and perforation diameter is 4 mm. For this objective, a simulation model was created in the wellbore using the ANSYS Fluent simulation software by using the standard k-ε model and applied to the (CFD) by changing the axial flow from (40-160) lit/min and constant inflow through perforations from range (0 - 80) lit/min. According to the study's findings, the increase in the radial flow through the perforations increases the total flow rate ratio and the total pressure drop and vice versa. In addition, an increase in the axial flow mixed with radial flow increases the total pressure drop, friction factor, and a decrease in productivity index. Furthermore, the percentage error of the total pressure drop between the numerical and experimental results in test 4 is about 3.83 %. It was found that the numerical and experimental results represented a good agreement about the study of the flow-through perforations at 90° angle in terms of pressure drop and productivity index, etc.
Castor Oil is a natural raw material, used to prepare Brominated Castor Oil (BCO) and quaternary ammonium salt based castor oil (TEt-CO). The two products were tested as demulsifiers and compared with a commercial demulsifier (Chimec2439) by using bottle test method. BCO showed a high ability on water separation efficiency 90% with a dose of 150µl at 120min time settling while TEt- CO showed a low water separation efficiency reached to 10%. The effect of the demulsifier BCO was tested by varying different variables which have an obvious effect on water separation efficiency such as: dose, temperature, time of mixing emulsion, pH and salinity of aqueous phase of emulsion, and water ratio. The effect of some additives (i.e. methanol, ethanol, xylene and toluene) on the efficiency of the BCO was tested for the purpose of enhancing its effectiveness to break the crude oil emulsion. The experimental data obtained by using BCO were formulated as a model using the Artificial Neural Networks (ANNs) to evaluating the water separation efficiency. Multi-layer perceptron artificial neural network was developed based on the collected data of this study. The results showed that the training algorithm of back propagation (BP) is sufficient enough in predicting BCO efficiency under different operation conditions. It was found that the correlation coefficient values are 0.9995 and 0.9999 for the testing and training data, respectively and the mean square error (MSE) was 6.18*10^-5 at 200 epochs.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
Due to the significance of structural sandwiches with hexagonal cores, utilized in various applications including aerospace, marine industries, and rail transport, and their design that imparts superior strength compared to conventional forms. In this paper, fracture behavior of these structural sandwiches was examined. Initially, the equivalent modulus of elasticity was empirically determined for many cell side lengths, utilizing the stress-strain relationship derived from tensile tests on hexagonal specimens. The fracture behavior was analyzed numerically using Abaqus software. The core and the complete sandwich structure were examined under various loads, including tensile and shear forces. The influence of the hexagonal cell dimensions on the fracture modules and the stress intensity factor (SIF), was assessed. It was observed that when the cell thickness remains constant while the side length varies, the SIF increases with the increasing in side length. This leads to the influence of stiffness, where it decreases with the increase in side length of the cell core. For instance, when the side length is 10, the stress intensity factor is 4.821, while when the side length is 20, the stress intensity factor becomes 22.35. A relationship was found between the stress intensity factor and thickness, similar to the tension case. However, here, a relationship between (kl) and the (a/tc) ratio was established.
This research studied the critical load of composite columns theoretical and numerical by using ANSYS14 package depended on experimental tensile properties of composite specimens. The composite specimens were prepared by hand lay-up technique made from unsaturated polyester reinforced with glass fibers with different fiber volume fraction V f , aspect ratio (L/T), and angle of fibers for coarse and fine woven fibers. The critical load that obtained by using program (ANSYS 14) have also shown a good agreement with results that were obtained theoretically and the maximum difference was (0.7%). The results show that the maximum value of the critical load can be observed at V f =11%, L/T = (3.5) and θ = (0 º /90 º ) for fine woven fibers was (622.115N). Also its found the maximum critical load for coarse woven fibers can be observed at V f %=8%, L/T=(3.5) and θ = (0 º /90 º ) was (486.887N). Also the observed values of tensile properties and predicated values are scattered close to the (45 ˚ ) line.
The functionally graded beam is a wide field of research, which attracts great interest today in the field of engineering, science, and medicine society. This type of beam is made from functionally graded material that is characterized by several properties one of them is the high strength to weight ratio. In the current years, this beam has witnessed great developments in the mechanism of its composition and the materials used in its manufacture. This research provides an overview of the properties, types, advantages and challenges, and applications of the functionally graded materials. In addition, this paper review provides a summary of the analysis of bending and buckling that occurs on the functionally graded beam with and without crack effect from (2008-2021) year. Through this review, the following was noted: Firstly, a small number of researchers have worked experimentally, and the properties of a beam in most of the research are gradual towards thickness using the mixing rule. Secondly, the crack has a very severe effect on the behavior of both bending and buckling for the graded beam. This critical review can be considered a milestone in future analyzes of the graded beam and is also beneficial to designers and researchers working in this field.
The natural convection heat transfer in a porous media filled and isothermally heated from the bottom wall of triangular enclosure is analyzed using finite element software package (FLEXPDE). Darcy's law was used to write equations of porous media . The curved bottom wall shape, with Radii R= 0.8 , 1 and 1.5, was applied to a triangular enclosure. The boundary condition of the vertical wall is isothermal and of the inclined wall is adiabatic. The study was performed for different Rayleigh numbers (100 ≤ Ra ≤ 1000 ) and aspect ratios (0.4 ≤ AR ≤ 1 ) . Numerical results are presented in terms of streamlines, isotherms and Nusselt numbers. It was observed that heat transfer enhancement was formed with increasing Rayleigh number and aspect ratio . A comparison of the flow field and isotherm field is made with that obtained by [11], which revealed a good agreement .
This paper proposes a fuzzy logic based controller for boost type DC/DC converter. It forms an improvement to the dynamic performances of the well known PI like fuzzy controller which uses the output voltage error & its rate of change as an inputs. The proposed controller generates a duty ratio control signal through the addition of a weighted part of the input voltage and of the low pass filtered signal of the inductor current to that of the fuzzy controller which is fed by voltage error and a signal representing the differences of the output voltage from its low pass filtered version. The controlled boost DC/DC converter exhibited excellent performances under small and larger disturbances of the input voltage and output load resistance and also showed good reference tracking ability.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
The dieless drawing process is an innovative method emanated and appeared in coincidence with development of the concept of metal superplasticity. It is utilized from the local heating of a wire or tube to a specified temperature and followed by a local cooling, so an additional deformation is inhibited. In this study, a special dieless drawing machine was designed to carry out an experimental program on SUS304-stainless steel wire having diameter of (1.6-2) mm to investigate the main process parameters such as speeds, heat quantity, heating coil width and heating-cooling separation distance. Also, a numerical model based on thermo-mechanical analysis was developed and validated with experimental program. Furthermore, an artificial neural network ANN model based on current experimental data was prepared to predict the dieless drawing behavior. A maximum area reduction of 40.7% was obtained in single pass. A 3.12mm/s feeding velocity and 4.97mm/s drawing velocity were realized through the experimental tests. The results showed that both drawing force and wire profile were effected by increasing of feeding speed, heating coil width and separation distance. Also, it is confirmed that strain rate was reduced by increasing the heating coil width and the reduction ratio was promoted. A maximum error of 21% was recorded between ANN model and experimental results. The results showed a good agreement among experimental, numerical and ANN models.
In this work, the turbulent buoyancy driven fluid flow and heat transfer in a differentially heated tall rectangular enclosure filled with nanofluid is quantified numerically. The two dimensional governing differential equations (continuity, momentum, energy and low Reynolds number LRN k-ω turbulence equations) are discretized using the finite volume method. SIMPLE algorithm is employed to obtain stabilized solution for high Rayleigh numbers. Two types of nanofluids namely, Al2O3-water and Cu-water, were considered. The effect of Rayleigh number (1010 to 1012), diameter of nanoparticles in the range 25-100 nm, nanoparticle volume fraction in range 0-0.08 and the aspect ratio (30, 40 and 50) on fluid flow and heat transfer are investigated. The present results are compared with previously published work and a qualitative agreement with good validation is obtained. Results show that addition of nanoparticles makes the liquid be more viscous which decreases the vertical velocity component and also decreases the temperature gradient near the walls. Also an announced heat transfer enhancement is obtained with nanoparticle volume fraction reaching a maximum point called optimal volume loading, at which the maximum convective heat transfer is obtained, and then it decreased with further increase of volume fraction.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
This paper investigates the possibility of recycled aggregate use in concrete slabs with hollow cores. The main variables considered in the experimental study for the slabs were the recycled aggregate percentage and the hollow core number. Six slabs with dimensions of (1000 × 500 × 120) mm was fabricated and tested. The results showed that the addition of recycled aggregate in the concrete slabs affected the ultimate strength, ductility, and energy absorption of the concrete members. An increase of the recycled aggregate percentage to 25 % decreased the ultimate strength capacity by 3.54 %, but the increase of recycled aggregate to 50 % led to a decrease in the ultimate strength of about 6.64%. The existence of a hollow core reduced the cracking and ultimate load capacity of the RCA slabs, and this reduction was according to the core number which the fabrication of more cores caused more decrement. The ductility and energy absorption were decreased when the replacement ratio of the recycled aggregate increased. Also, the core number affected the ductility and energy absorption. The energy absorption was the most property affected by the core number increase which caused an average reduction of 71.5 % when the core number increased from two to three hollow cores.
The current approach to cooling water treatment is to use a multi – component inhibitors. Cooling water formulations containing mixtures of inhibitors usually offer better and increased protection to ferrous metals than similar concentrations of either of the individual components. Such mixtures are synergistic in their action .But; the synergistic effects between nitrites, molybdates and inorganic phosphate were not investigated until recently. A weight loss technique was used to investigate such mixture and to optimize the concentrations of the components in the blend.Consequently; an efficient and effective blend was developed as a corrosion inhibitor for carbon steel in aerated Al–Daura refinery re-circulating cooling water in the pH range 6.75 to 7.25. The preferred concentrations of components in the multi- component inhibitor blend (as ppm ) were: (SN + SM): SHMP = 800: 20 with SN: SM weight ratio =3:2.The reduction in corrosion rate was 97.6 % .
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
Solar energy is the most suitable among all renewable energy options for competing with fossil fuels in desalination due to its ability to utilize both heat and power for the process. In this study, the Parabolic Trough Solar Collector (PTSC) for powering a Single Stage Flash (SSF) desalination unit was proposed for Basrah city climate, Iraq. The desalination system comprises two directly coupled sub-systems: the PTSC and the SSF desalination unit. The preheated feed brine water coming from condenser was used as a Heat Transfer Fluid (HTF) for PTSC, which gets heated to a desired temperature referred to as the Top Brine Temperature (TBT). The numerical simulations were performed via EBSILON professional 16.02 (2022) software. The effects of TBT, mass flowrate of feed brine water to get the desired TBT, solar collector area, and vacuum pressure inside flash chamber on the performance of the desalination system was studied. A major finding of the current study can be summarized as follows: The collector efficiency is enhanced eventually as TBT increases. The maximum values of distillate water in June are around 5.5, 4.56, 3.69, 2.75 and 1.85 kg/h for 12.408, 10.434, 8.3472, 6.26, and 4.1736 m² collector area respectively, when TBT 107 °C and vacuum pressure 40 kPa. For 1.598 m² collector area, the total distillate in the 1st of June amounted to 7.9 kg, with an average production rate of around 0.7 kg/h. The solar SSF system's productivity per solar collector unit area at 20 kPa, 15 kPa, and 10 kPa vacuum pressures was 4.7 kg/day/m², 5.3 kg/day/m², and 6.25 kg/day/m², respectively. The average Performance Ratio (PR) values are determined to be 0.694, 0.577, and 0.491 for 10 kPa, 15 kPa, and 20 kPa, respectively. These results are very acceptable when compared with an existing literature.
This numerical study aimed to investigate the torsional behaviour of hollow cross section reinforced concrete members strengthened with steel fibers (end hooked and corrugated), subjected to pure torsion. The numerical results were compared with experimental results and show good agreement. The experimental study was conducted on ten steel fiber reinforced concrete specimens with low longitudinal reinforcement ratio to investigate the torsional behavior under pure torsion. For this analysis, a computer program (ANSYS 18.2) was used. The brick elements 8-nodes (SOLID65) were used to concrete simulation, while the steel bars simulated as axial members (link 180). The steel fibre was represented theoretically by the stress-strain relationship. The theoretical results indicated that the adopted smeared crack model is capable of making relatively acceptable estimations of cracking and ultimate torsional capacity of the members.
This paper deals with the computer simulation of stress distribution in a plane model of mild steel under biaxial tensile loading. The goal is to visualize the crack behavior under deferent ratios of biaxial loading through linear elastic fracture mechanics theory. A finite element method is considered in calculating the mixed mode of stress intensity factor that governing the influence of stresses distribution around the crack. Aspects of crack propagation are considered. It is found that the mw.imum ci..-cumfcrcnce .stress is not of the plane of crack but that inclined by an angle (68) from it.
An investigation was conducted to study the effect of loading level with respect to shear center and span length on lateral torsional buckling of steel I-section beams using linear and nonlinear finite element analysis available in ANSYS (version 12.0) computer program. The steel beams which have been studied included prismatic beams and linearly web- tapered beams with web tapering ratio of (0.5). The maximum height of all beams was 300 mm with span length of 4, 6 and 8 m. The critical buckling loads for prismatic and linearly tapered cantilever and simply supported beams subjected to point load and uniformly distributed load were determined. The results showed that, the bottom flange loading gives a buckling loads higher than that of the top flange loading with percentage increases of 148% and 155% for the linear and nonlinear analysis respectively for the prismatic beams. While for the tapered beams, these percentages increases were 61% and 67% respectively.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
Interest in neural networks as an alternative to the conventional algorithmic techniques has grown rapidly in recent years. Noise removal or noise suppression is an important task in image processing. In general, the results of the noise removal have a strong influence on the quality of the following image processing techniques. In this paper, two feed forward NN schemes have been presented for impulsive noise removal. The computation is reduced by using an artificial image in training. Results of NN schemes show high performance especially when the ratio of impulsive noise in testing are the same or greater than that of training image. The presented schemes are used for grayscale and also for truecolor.
The effect of pore fluid chemistry on the engineering properties of soil in Garmatt-Ali zone of Basrah was investigated. The tested soil is described as silty clay of low plasticity. The pore fluid was altered to include distilled water, raw sewage, and solutions of various salts such calcium carbonate, magnesium sulphate, and calcium chloride. Also, the solutions of salts were used with different concentration (0.25, 0.5, 0.75, 1.0 normality). The prepared samples of soil were tested after different exposure periods. The test program included determination of shear strength characteristics, consolidation characteristics, and Atterberg limits. The changes in shear strength, coefficient of permeability, void ratio – effective stress relationship, and Atterberg limits were recorded with the change in exposure period or the concentration of pore fluid solution. Generally, it was found that there are reductions in the shear strength of soil when the pore fluid is changed from distilled water to solutions of salts or raw sewage. Also it was found that there is a change in the calculated values of permeability, upon changing the type of pore fluid. The coefficient of consolidation for polluted soil was found to be less than that for the reference samples with distilled water.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
The choice of aggregate type in producing reinforced concrete depends on the availability of the source sometimes and the intended concrete requirements like lightweight or normal aggregate concrete or high strength concrete. The punching shear resistance is being considered to be influenced by numbers of parameters including aggregate size and types. These parameters have not accounted in most of codes of design and have given a little attention by researchers. Most of available knowledge are based on outcomes from experimental works on beams. In this paper, the considerable slab tests without shear reinforcement are collected from literature in which aggregate types and sizes are given and they were failed in punching. The test results are compared to those calculated by ACI, EC2 and CSCT. The deficits of shear resistance are found clear where high compressive strength is combined with reinforcement ratio.
The present work investigates the effects of drinking water on the erosion- corrosion rate and Vickers hardness of (Al-Si) and (Al-Mg-Si). (Al-Si) alloy Which is well-known as casting alloy with high wear resistance, low thermal expansion coefficient, good corrosion resistance and improved hardness at a wide range of temperatures While (Al-Mg-Si) alloys have good formability, weld ability, machine ability and corrosion resistance. The alloys specimens which are used for piping and containing water and carbonated water were exposed in erosion- corrosion system in factories by using drinking water type AQUAFINA as exposure media for different exposure time (1-30)h. to measure the erosion-corrosion rate. The results show that there is small different in the rate of corrosion, moreover (Al-Mg-Si) alloy have high resistance to erosion-corrosion in drinking water due to the consisting of (Mg2Si) phase which is precipitate as fine particles due to resist dislocations movement lead to high corrosion strength and the (Al-Si) alloy have high Vickers hardness at natural aging due to the present of high ratio hardening silicon element.
The goal of this study is to evaluate the mechanical characteristics and energy absorption capabilities of both closed-cell pure Aluminum foam and closed-cell A356 foam. A portion of the lightweight pure foam samples (17.12, 17.77 and 15.27 g) is produced through casting of raw material (99.9 % pure aluminum) using Titanium Hydride (TiH 2 ) as a foaming agent, which lead to (7.5, 7 and 8) Pores Per Inches (PPI); and samples of A356 foam (38.24, 38.18 and 35.88 g) is produced through casting of A356 alloyed material with same procedure which lead to (11, 10 and 12) PPI. In order to determine the maximum compressive strength, strength-to-weight ratio, energy absorption density, complementary energy, and energy absorption efficiency, a uniaxial compression test is conducted. The results indicate that compression of pure foam structure smashed in a ductile manner and shows a lamellar eutectic structure while A365 foams under compression are crashed with brittle character with complex phases distribution inside (polyhedral and globular morphologies), A noticeable enhancement is observed in the mechanical characteristics of the A356 foam. The maximum compressive strength and specific energy absorption of alloyed foam are increased by a factor nearly of 4 and 2 respectively for all tested samples. Also, the result shows a significant decreasing in compressive strength with increasing of PPI for both pure and alloyed foam. The notable enhancements in the properties of alloyed closed cell foam render these advanced materials a viable option for high-strength applications.
An incompressible three dimensional continuity and Navier-Stokes (momentum equations) equations are numerically solved to obtain the pressure drop and fluid friction in laminar steady state micro-channel flow of water. The governing equations are solved by using SIMPLE algorithm with finite volume method and FORTRAN code to obtain pressure field in rectangular micro-channel and then from the pressure field both friction factor f and friction constant Cf are obtained. The results showed that the factors affecting the pressure drop, friction factor f and friction constant Cf are; channel length L, Reynolds number Re, aspect ratio a, channel volume Vch and hydraulic diameter Dh. Increasing of channel length L leads to increase each pressure drop, f and Cf. On other hand, increasing of Re leads to increase pressure drop and decrease the f, while the Cf increase with low value of Re (Re less than 50) and then nearby with approximately constant value. Moreover, increasing of a, Vch and Dh separately leads to decrease pressure drop and increase both f and Cf.