Authors:B.M. Vinay Kumar; H. Ananthan; K.V.A. Balaji Pages: 100 - 108 Abstract: Publication date: Available online 26 May 2017 Source:Alexandria Engineering Journal Author(s): B.M. Vinay Kumar, H. Ananthan, K.V.A. Balaji This experimental study deals with utilization of Coarse Recycled Concrete Aggregate (CRCA) and Fine Recycled Concrete Aggregate (FRCA) in High Performance Concrete (HPC) mixes. The concrete mix is designed for target strength of 60MPa. Four mixes are considered in the study viz., Control Mix (CM) with natural aggregates, 20% replacement of CRCA, FRCA and both. The fresh and hardened properties are assessed for all the four mixes. The experimental results indicate the satisfactory performance of all the four mixes with respect to hardened properties. The HPC mixes with 20% FRCA content shows reduction in workability and requires a higher dosage of Superplasticizer (SP) to achieve a slump of 170±10mm. The durability tests such as sulphate and acid attack are conducted for the mix containing 20% CRCA and FRCA. The mix is found to be least susceptible to sulphate attack. The significant reduction in compressive strength is noticed, when the HPC mix is exposed to H2SO4 solution.
Authors:E.M. Attia; N.M. Elsodany; H.A. El-Gamal; M.A. Elgohary Pages: 189 - 200 Abstract: Publication date: June 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 2 Author(s): E.M. Attia, N.M. Elsodany, H.A. El-Gamal, M.A. Elgohary A Magneto-Rheological (MR) fluid disc brake is a device that transmits a torque by the shear force of MR fluid. The fluid is inserted between the rotating and fixed discs and a magnetic field is imposed on the fluid. In this paper, a complete test rig for an MR fluid disc brake is introduced. Experiments are conducted to measure the braking torque and speed of shaft during braking process and the results are presented at different voltage input to the brake. Also theoretical analysis for both MR brake and the mechanical system is developed and is solved numerically using finite difference method and Matlab software. Effect of current input to the MR brake, viscosity of fluid and design parameters is taken into consideration. A validation of the theoretical results with CFD model is introduced. The experimental results are performed and both angular velocity and the braking torque are obtained as responses during the braking process. A comparison between braking torques obtained from theoretical and experimental work shows agreement when voltage is 2V at speed of 150rpm and also agreement when voltage is 2 and 3V at speed of 250rpm.
Authors:Mohamed Ghorab; Evgueniy Entchev; Libing Yang Pages: 201 - 212 Abstract: Publication date: June 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 2 Author(s): Mohamed Ghorab, Evgueniy Entchev, Libing Yang In recent years Solar Domestic Hot Water systems have increased significantly their market share. In order to better understand the real-life performance of SDHW systems, a single detached house was selected for extensive monitoring. Two solar panels were installed on the house roof to provide thermal energy to the Domestic Hot Water (DHW) system. The house was equipped with data logging system and remotely monitored with performance data collected and analyzed over one year. The paper presents the inclusive analysis and performance evaluation of SDHW system, including DHW recirculation loop, under Canadian weather conditions for average family occupancy (two adults and two kids) with daily average DHW, draws of 246L. Moreover, the study is carried out a significant recommendation to improve the SDHW performance, decrease the gas energy consumption and reduce greenhouse gas (GHG) emissions. The SDHW performance depends mainly on DHW flow rate, draw time and duration, city water temperature, DHW recirculation loop control strategy and system layout. The performance analysis results show that 91.5% of the collected solar energy is transferred to the DHW heating load through the solar tank. The contribution to DHW heating load is about 69.4% from natural gas and 30.6% from solar. The recirculation loop is responsible for close to 34.9%, of DHW total energy.
Authors:Mahmoud T. El-Sayed; Mohamed N.A. Nasr; B.M. El-Souhily; Mahmoud A. Moustafa Pages: 213 - 223 Abstract: Publication date: June 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 2 Author(s): Mahmoud T. El-Sayed, Mohamed N.A. Nasr, B.M. El-Souhily, Mahmoud A. Moustafa Most of the shaft theories have based their analysis on bending moment, twisting moment or combined between them. Nevertheless, the dynamic behavior of flexural-torsional coupled vibrations in the rotating shafts is affected by the internal resistance forces due to torsion. It is expected that the deflected shafts shall be exposed to this resistance, where these forces were not considered in the analysis before. The objective of the present work was to estimate the effect of internal torsional resistance in shafts which is caused by deflection, for the reason that it has the upper hand on misalignment problem. With the aim of fulfilling this objective, an experimental rig has been constructed to verify the existence of the torsional resistance in deflected shafts and its variation with the rotation angle.
Authors:Md. Asaduzzaman; Ali Newaz Bahar; Md. Mohiuddin Masum; Md. Mahmodul Hasan Pages: 225 - 229 Abstract: Publication date: June 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 2 Author(s): Md. Asaduzzaman, Ali Newaz Bahar, Md. Mohiuddin Masum, Md. Mahmodul Hasan We have investigated the simulation approach of a one-dimensional online simulator named A Device Emulation Program and Tool ( ADEPT 2.1 ) and the device performances of a thin film solar cell based on Cu 2 ZnSn ( S,Se ) 4 ( CZTSSe ) absorber have been measured. Initiating with a thin film photovoltaic device structure consisting of n-ZnO : Al / i-ZnO / Zn 1 - x Sn x O y ( ZTO ) / CZTSSe / Mo / SLG stack, a graded space charge region ( SCR ) and an inverted surface layer ( ISL ) were inserted between the buffer and the absorber. The cadmium ( Cd ) free ZTO buffer, a competitive substitute to the CdS buffer, significantly contributes to improve the open-circuit voltage, V oc without deteriorating the short-circuit current density, J sc . The optimized solar cell performance parameters including V oc , J sc , fill factor ( FF ) , and efficiency ( η ) were calculated from the current density-voltage curve, also known as J – V characteristic curve. The FF was determined as 73.17 % , which in turns, yields a higher energy conversion efficiency of 14.09 % .
Authors:S. Ashok Kumar; T. Shanmuganantham; D. Dileepan Pages: 231 - 234 Abstract: Publication date: June 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 2 Author(s): S. Ashok Kumar, T. Shanmuganantham, D. Dileepan The behaviour of various families of the antenna structures is studied. In that, CPW (Coplanar Waveguide) fed antennas show better behaviour for the Wireless applications. The slot antenna is used for precise operating frequency, where the frequency spectrum is 2.45GHz and 5.5GHz. To achieve the proposed frequency, the slot antenna is fed with Coplanar waveguide is implemented and measured with dimensions of 70mm×70mm. To increase the bandwidth, first the mid section of two short slots of either side of the single pole length is increased slowly to check out the maximum bandwidth. The achieved peak bandwidth gradually starts decreasing at some length, considering the achieved peak value, The length responsible for decreasing peak value is to be noted. Now for obtaining the operating frequency lies in the frequency band, the mid section of long slot has to be decreased gradually; thus, operating frequency shows at 2.45GHz and 5.51GHz with return loss of −20dB, and the whole design is printed on the FR4 substrate for better efficiency to the proposed frequency at maximum bandwidth, and thereafter to check out the characteristics of antenna the parameters such as Return loss characteristics, VSWR, Azimuth pattern, Elevation pattern and 3D distribution pattern.
Authors:N. Mahalakshmi; A. Thenmozhi Pages: 235 - 239 Abstract: Publication date: June 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 2 Author(s): N. Mahalakshmi, A. Thenmozhi This paper presents a novel hexagon shape bow-tie antenna for implantable bio-medical application at a frequency ranging from 2.4GHz to 2.48GHz of ISM band. In order to achieve high frequency response the proposed antenna is designed with CPW feed. Alumina ceramic ( Al 2 O 3 ) is used as the substrate material with 1mm thickness and the dielectric constant is 9.8. The proposed antenna has the total size of 10∗10∗1mm which is located at human tissues such as muscle, fat and skin and some of the parameters such as gain, return loss, radiation pattern and VSWR are measured. The main advantage of the proposed system is it has reduced size with increased accuracy. The proposed antenna possesses the return loss of −29dB at 2.43GHz. Thus the proposed hexagon shape bow-tie antenna can be employed for several implantable applications.
Authors:Hamdy Abou-Elfath; Mostafa Ramadan; Mohamed Meshaly; Heba Alzobair Fdiel Pages: 241 - 249 Abstract: Publication date: June 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 2 Author(s): Hamdy Abou-Elfath, Mostafa Ramadan, Mohamed Meshaly, Heba Alzobair Fdiel The design of Moment Resisting Steel Frames (MRSFs) is usually governed by drift limits rather than strength because of their high flexibility. The purpose of this study is to evaluate the seismic performance of a 6-story MRSF designed according to the Egyptian code with three different levels of allowable story drift limits: 0.5%, 0.75% and 1.0%. Seismic evaluation in this study has been carried out by static pushover analysis and time history earthquake analysis. Ten ground motions with different PGA levels are used in the analysis. The mean plus one standard deviation values of the roof-drift ratio, the maximum story drift ratio and the maximum beam- and column-strain responses are used as the basis for the seismic performance evaluations. The results obtained indicated that the strength and the initial stiffness of the designed frames decrease as the allowed story drift limit of the frame increases. Two of the designed frames exhibit maximum story drifts that are higher than the allowed limits specified by the code. The maximum story drift and beam-strain responses of the designed frames under the earthquake loading increase with the increase in the allowable story drift limits.
Authors:Hamdy Abou-Elfath; Mostafa Ramadan; Fozeya Omar Alkanai Pages: 251 - 262 Abstract: Publication date: June 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 2 Author(s): Hamdy Abou-Elfath, Mostafa Ramadan, Fozeya Omar Alkanai Many existing RC buildings do not meet the lateral strength requirements of current seismic codes and are vulnerable to significant damage or collapse in the event of future earthquakes. In the past few decades, buckling-restrained braces have become increasingly popular as a lateral force resisting system because of their capability of improving the strength, the stiffness and the energy absorbing capacity of structures. This study evaluates the seismic upgrading of a 6-story RC-building using single diagonal buckling restrained braces. Seismic evaluation in this study has been carried out by static pushover analysis and time history earthquake analysis. Ten ground motions with different PGA levels are used in the analysis. The mean plus one standard deviation values of the roof-drift ratio, the maximum story drift ratio, the brace ductility factors and the member strain responses are used as the basis for the seismic performance evaluations. The results obtained in this study indicate that strengthening of RC buildings with buckling restrained braces is an efficient technique as it significantly increases the PGA capacity of the RC buildings. The results also indicate the increase in the PGA capacity of the RC building with the increase in the amount of the braces.
Authors:N. Sandeep; I.L. Animasaun Pages: 263 - 269 Abstract: Publication date: June 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 2 Author(s): N. Sandeep, I.L. Animasaun This study reports the enhanced heat transfer of electrically conducting magnetic-nanofluids with thermal radiation and inclined magnetic field effects. We consider water as a base fluid embedded with the two different types of aluminum alloy nanoparticles namely AA 7072 and AA 7075. AA 7072 is a special type of heat treatable aluminum alloy with 98% Al and 1% of Zn with the additives such as Si, Fe and Cu. Similarly, AA 7075 contains 90% Al, 5–6% Zn, 2–3% Mg, 1–2% Cu with the additives such as Si, Fe and Mn. Numerical results are explored with the aid of R-K and Newton’s techniques. Results are depicted diagrammatically and discussed on the common profiles of interest (velocity and temperature). The heat transfer rate of water-AA 7075 nanofluid is significantly high when compared with the rate of heat transfer of water-AA 7072 nanofluid.
Authors:Bahram Agheli; Rahmat Darzi Pages: 271 - 276 Abstract: Publication date: June 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 2 Author(s): Bahram Agheli, Rahmat Darzi We have applied the new approach of homotopic perturbation method (NHPM) for Burger differential system equations featuring time-fractional derivative. A combination of NHPM and multiple fractional power series form has been used the first time to present analytical solution. In order to illustrate the simplicity and ability of the suggested approach, some specific and clear examples have been given. All numerical calculations in this manuscript have been carried out with Mathematica.
Authors:M. Sheikholeslami; M. Nimafar; D.D. Ganji Pages: 277 - 283 Abstract: Publication date: June 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 2 Author(s): M. Sheikholeslami, M. Nimafar, D.D. Ganji Nanofluid flow between two circular cylinders is studied in existence of magnetic field. KKL model is applied for nanofluid. Thermal radiation effect has been considered in energy equation. AGM is selected for solving ODEs. Semi analytical procedures are examined for various active parameters namely; aspect ratio, Hartmann number, Eckert number and Reynolds number. Results indicate that temperature gradient enhances with rise of Ha, Ec and η but it reduces with augment of Re. Velocity reduces with rise of Lorentz forces but it augments with rise of Reynolds number.
Authors:Dharmendra Tripathi; Shashi Bhushan; O. Anwar Bég Abstract: Publication date: Available online 21 June 2017 Source:Alexandria Engineering Journal Author(s): Dharmendra Tripathi, Shashi Bhushan, O. Anwar Bég Electrokinetic transport of fluids through microchannels by micro-pumping and micro- peristaltic pumping has stimulated considerable interest in biomedical engineering and other areas of medical technology. Deeper elucidation of the fluid dynamics of such transport requires the continuous need for more elegant mathematical models and numerical simulations, in parallel with laboratory investigations. In this article we therefore investigate analytically the unsteady viscous flow driven by the combined effects of peristalsis and electro-osmosis through microchannel. An integral number of waves propagating in the microchannel are considered as a model for transportation of fluid bolus along the channel length. Debye-Hückel linearization is employed to evaluate the potential function. Low Reynolds number and large wavelength approximations are employed. Closed-form solutions are derived for the non-dimensional boundary value problem. The computations demonstrate that magnitude of electric potential function is increased with a decrease in the thickness of the electrical double layer (EDL). Stronger electric field also decelerates the flow and decreases local wall shear stress. Hydrodynamic pressure is increased with EDL thickness whereas it is suppressed with electric field. Streamline visualization reveals that the quantity of trapped bolus is decreased with increase in EDL thickness and also with higher external electric field.
Authors:Yokus Abstract: Publication date: Available online 19 June 2017 Source:Alexandria Engineering Journal Author(s): Asıf Yokus In this paper, we study the fractional differential operators thereby considering the space and time order Burger type equation with initial condition. The extended finite difference method which is based on shifted Grünwald, Caputo and Riemann formulas are used. The fractional terms are approximated using two fractional difference schemes. Time Order Burger type Equation, Space Order Burger type Equation and Space-Time Order Burger type Equation are discussed with an example and error estimates obtained for the Finite difference method (FDM) and Generalized Taylor Series Methods (GTSM). The numerical methods have been applied to solve a numerical example, and results are compared with the exact solutions. By these methods, the numerical solutions of space and time order Burger type equation are obtained with the help of Wolfram Mathematica 11 software package. We present the tables of the obtained numerical results.
Authors:Magdi El Messiry; Shaimaa El-Tarfawy; Rania El Deeb Abstract: Publication date: Available online 19 June 2017 Source:Alexandria Engineering Journal Author(s): Magdi El Messiry, Shaimaa El-Tarfawy, Rania El Deeb The objective of this work was to study the influence of low fiber volume fraction on the mechanical properties of the Jute fabric reinforced cementitious composites, suggesting the thin sheet of pultruded fabric instead of Jute as a suitable solution for the forming complex matrix shapes. The present work investigates the pultrusion of a Jute fabrics reinforced by the polymeric matrix material, which protects the Jute fabrics and improves the durability of fiber cement sheets. Different fiber volume fraction as well as polymeric matrix material blending ratios were investigated through the pultrusion technique and compared with the control untreated Jute fabrics reinforced cementations composites. Microstructure characteristics of the fabric–matrix interface were also explored and correlated with the mechanical properties of the pultruded Jute fabrics reinforced cementations composite. It was found that an improvement in the behavior of mechanical properties of the cement composite with pultruded Jute fabrics compared to similar composites. Acceptable correlations were found on the mechanical properties of the composite, particularly bending stiffness. Pultrusion Jute reinforced polymeric matrix material increases the tensile stress, the modulus of elasticity, and the flexure strength than in control untreated Jute fabrics reinforced cementations composites.
Authors:Vikas Poply; Phool Singh; A.K. Yadav Abstract: Publication date: Available online 19 June 2017 Source:Alexandria Engineering Journal Author(s): Vikas Poply, Phool Singh, A.K. Yadav A study has been done on axisymmetric magnetohydrodynamic (MHD) flow of a viscous incompressible outer velocity fluid along a stretching cylinder. The momentum and heat partial differential equations are mold using similarity transformations into a set of nonlinear ordinary differential equations. These equations have been solved with the help of Runge-Kutta Fehlberg scheme numerically with shooting technique. It is found that the solution is not unique for stretching cylindrical surface. The dual solution exists for a certain range of fluid parameters on stretching surface. The stability analysis shown that the upper branch is a stable solution and the lower branch is a unstable solution. The critical point λ c = - 0.03211 of outer velocity parameter and the range of the unstable solution - 0.03211 = λ c ⩽ λ ⩽ λ r = 0.1411 have been obtained for certain magnetic parameter. Also, the effects of MHD and outer velocity parameter with various other fluid parameters on heat transfer and flow characteristics have been analyzed and shown by figures and tables. The outcomes show that the outer velocity parameter has a substantial effect on MHD fluid flow in stretching cylindrical surface.
Authors:M.S.R. Naidu; P. Rajesh Kumar; K. Chiranjeevi Abstract: Publication date: Available online 19 June 2017 Source:Alexandria Engineering Journal Author(s): M.S.R. Naidu, P. Rajesh Kumar, K. Chiranjeevi Image segmentation is a very important and pre-processing step in image analysis. The conventional multilevel thresholding methods are efficient for bi-level thresholding because of its simplicity, robustness, less convergence time and accuracy. However, a mass of computational cost is needed and efficiency is broken down as an exhaustive search is utilized for finding the optimal thresholds, which results in application of evolutionary algorithm and swarm intelligence to obtain the optimal thresholds. The main aim of image segmentation was to segregate the foreground from background. For the first time this paper established a naturally inspired firefly algorithm based multilevel image thresholding for image segmentation by maximizing Shannon entropy or Fuzzy entropy. The proposed algorithm is tested on standard set of images and results are compared with the Shannon entropy or Fuzzy entropy based methods that are optimized by Differential Evolution (DE), Particle Swarm Optimization (PSO) and bat algorithm (BA). It is demonstrated that the proposed method shows better performance in objective function, structural similarity index, peak signal to noise ratio, misclassification error and CPU time than state of art methods.
Authors:N. Kousar; R. Mahmood; A. Nawaz Abstract: Publication date: Available online 16 June 2017 Source:Alexandria Engineering Journal Author(s): N. Kousar, R. Mahmood, A. Nawaz Objectives The objective of this article was to simulate a mathematical model of diffusive transport of nutrients which affects the nonlinear cell proliferation rate. The governing coupled equations are solved under the assumption that the nutrient delivery to the scaffold is purely depends on diffusion. Methods The homotopy analysis method (HAM) is applied to find the approximate series solution for the nonlinear coupled PDEs. This method is very powerful analytical tool for solving nonlinear and coupled equations. Findings The results are obtained of different physical parameters for the uniform cell seeding strategy. The results show the appearance of cell proliferated regions near the nutrient supply. We have compared our results with the results given in the literature (Lewis et al., 2005). Novelty Upto the best of author’s knowledge, no series solution is found so far in the literature for this tissue engineering model.
Authors:H. Moustabchir; J. Arbaoui; Zitouni Azari; S. Hariri; Catalin Iulian Pruncu Abstract: Publication date: Available online 13 June 2017 Source:Alexandria Engineering Journal Author(s): H. Moustabchir, J. Arbaoui, Zitouni Azari, S. Hariri, Catalin Iulian Pruncu This paper presents an experimental-numerical investigation on the mechanical behaviour of pressurized cylindrical shells with external longitudinal and circumferential cracks of semi-elliptical shape. The research is motivated by the need to develop advanced design methodologies for shell structures. For that purpose, strain gauges are utilized to monitor strain concentrations near the cracks, and finite element simulations are carried out to predict the corresponding stress intensity factor distributions. A good agreement between numerical simulations and experimental data is found. This confirms that virtual simulations/calculations provide a reliable approach to evaluating mechanical behaviour of pressurized cylindrical shells with crack defects.
Authors:Mohamed El-Borhamy Abstract: Publication date: Available online 13 June 2017 Source:Alexandria Engineering Journal Author(s): Mohamed El-Borhamy In this work, numerical schemes for the generalized stationary regularized viscoplastic fluids equations with highly nonlinear viscosities are analyzed. The discretisation using certain high order finite elements ( Q 2 P 1 disc ) is achieved to transform the nonlinear continuous form to the corresponding nonlinear discretized one. The solution process is analyzed in the sense of successive continuous Newton method (CNM) with minimal residual method as a linear solver. The convergence of the method is proved using the sense of the minimization technique due to the monotone decreasing feature of their viscosities. It is shown that, the convergence process of the successive nonlinear iterative method is mostly approaching a semi-quadratic behavior for slow flow cases. The numerical tests are achieved to have good fitting with the theoretical results using a self implemented Matlab code for the interested problem.
Authors:Mohie El-Din Shoukry; Zaki I. Mahmoud; Nessreen A. Khalf Abstract: Publication date: Available online 12 June 2017 Source:Alexandria Engineering Journal Author(s): Mohie El-Din Shoukry, Zaki I. Mahmoud, Nessreen A. Khalf Recently, a considerable research effort has been devoted to bridge design and evaluation in Egypt. The traffic loading in the Egyptian code (ECP) gets heavier from 1963 to 2012. So, it was necessary to evaluate how much safe are the existing bridges when loaded with heavier traffic loading. For this reason, a comparative study is presented between the internal forces (bending moments) in longitudinal girders and deck slabs, in slab/girder bridges, resulting from traffic loads recommended by ECP 1963, ECP 1994 and ECP 2012. Tables and figures are displayed to show the variation in live load moments when using the three different codes for bridges with 10.5m width (three traffic lanes) and with spans 15, 20 and 25m. Since most highway bridges are continuous ones, the present analysis was expanded to cover the effects of the different recommended live loads on continuous bridges. The results reveal big differences between the different versions of traffic loads in the Egyptian codes. In addition, modified equations to calculate maximum moments in longitudinal girders according to ECP2012 are proposed. The proposed equations show excellent results when compared with the numerical study.
Authors:M. Nawaz; Rahila Naz; M. Awais Abstract: Publication date: Available online 12 June 2017 Source:Alexandria Engineering Journal Author(s): M. Nawaz, Rahila Naz, M. Awais This article examines Joule heating and viscous dissipation effects in axisymmetric stagnation point flow of Casson fluid with temperature dependent thermal conductivity. The governing boundary layer equations are transformed into a set of ordinary differential equations using the similarity transformations. Resulting boundary value problem is solved by homotopy analysis method (HAM). The homotopy solutions are compared with the numerical results. The behavior of sundry parameters is analyzed through the dimensionless velocity, temperature, wall shear stress and Nusselt number. The upshot of Casson fluid parameter appears to accelerate the fluid velocity. The system heats up by the effects of dissipation and Joule heating.
Authors:Rasha T.S. Mabrouk; Amr Bakr; Hany Abdalla Abstract: Publication date: Available online 10 June 2017 Source:Alexandria Engineering Journal Author(s): Rasha T.S. Mabrouk, Amr Bakr, Hany Abdalla Punching is one of the most important phenomena to be considered during the design of reinforced concrete flat slabs. Three main factors affect the punching behavior. These factors are concrete compressive strength, horizontal flexural reinforcement, and vertical shear reinforcement in the form of stirrups, studs or other forms. This paper is part of an ongoing research program conducted at the concrete laboratory of the Faulty of Engineering, Cairo University to assess the contribution of horizontal flexural reinforcement and vertical shear reinforcement on the punching behavior of reinforced concrete flat slabs. In the current research, seven half scale specimens are cast and tested. The specimens had dimensions of 1050×1050mm and a total thickness of 100mm. All specimens were connected to a square column of dimensions 150×150mm and loaded at the four corners with a span 950mm. The parameters considered in this research included spacing between vertical stirrups, width of the stirrups, number of stirrups branches and the ratio of the horizontal flexural reinforcement. During testing, ultimate capacity, steel strain, cracking pattern and deformation were recorded. The experimental results were analyzed and compared against values estimated from different international design codes.
Authors:Rasha T.S. Mabrouk; Ahmed Mounir Abstract: Publication date: Available online 9 June 2017 Source:Alexandria Engineering Journal Author(s): Rasha T.S. Mabrouk, Ahmed Mounir Many research studies have been carried out on the different parameters affecting the bond strength of tension lap splices in RC beams but limited attention has been given to the effect of using transverse reinforcement along the splice length. The first part of this research is an experimental program which consisted of sixteen reinforced concrete beams tested at the concrete laboratory of the Faculty of Engineering, Cairo University. The parameters under study herein are the diameter of the transverse reinforcement as well as its shape and distribution while using three different types of concrete. The beams were all simply supported with 1800mmspan and 150×250mm cross section. The tensile steel was spliced in the constant moment zone. The second part of the research consisted of an analytical study to enhance the understanding of the topic of this research. Three-dimensional nonlinear finite element analysis was carried with the help of the well-known finite element software; ABAQUS. The concrete damaged plasticity model is selected at this study because it is capable of representing the complete inelastic behavior of concrete both in tension and in compression including damage characteristics. The analytical and experimental results were compared and contrasted. Good agreement was obtained.
Authors:Isa Ebtehaj; Hossein Bonakdari; Amir Hossein Zaji Abstract: Publication date: Available online 7 June 2017 Source:Alexandria Engineering Journal Author(s): Isa Ebtehaj, Hossein Bonakdari, Amir Hossein Zaji A new hybrid decision tree (DT) technique based on two artificial neural networks (ANN), namely multilayer perceptron (MLP) and radial basis function (RBF), is proposed to predict sediment transport in clean pipes (i.e. without deposition). The parameters affecting densimetric Froude number (Fr) prediction were extracted from the literature in order to build the model proposed in this study. The effect of each parameter is first examined using MLP and RBF and a sensitivity analysis. According to the sensitivity analysis, the optimal model indicates that using the volumetric sediment concentration (CV ), median diameter of particle size distribution to pipe diameter (d/D) and ratio of median diameter of particle size distribution to hydraulic radius (d/R) parameters yield the best Fr prediction results. Subsequently, the hybrid DT-MLP and DT-RBF model results are compared with MLP and RBF. According to the results, MLP with all models predicted Fr more accurately than RBF, and DT-MLP exhibited the best performance (R 2 =0.975, MARE =0.063, RMSE =0.328, SI =00.081, BIAS =−0.01). Moreover, the comparison between DT-MLP and existing regression-based equations indicates that the models presented in the current study are superior.
Authors:G. Alaa El-Din; A.A. Amer; G. Malsh; M. Hussein Abstract: Publication date: Available online 3 June 2017 Source:Alexandria Engineering Journal Author(s): G. Alaa El-Din, A.A. Amer, G. Malsh, M. Hussein Nowadays, oil spill is one of the most serious pollutants that have negative effects on the ecosystem and marine life. Environmentalists face major challenges in the treatment of spills and in developing an alternative product with low cost. Among all different sorbents, agriculture waste is preferred as an oil cleanup technology due to its biodegradation and buoyancy. This study investigates the oil sorption capacity of crude and gas oils, using banana peel as a substitutional material from local fruit wastes. The research detected that the capacity of this sorbent to clean up crude oil from produced water toward different factors is associated with surface characteristics, oil type, oil film thickness, sorption time, temperature, in addition to the salinity of crude oil. Analytical techniques of banana peel, such as microstructure and morphology using FTIR spectrometry and scanning electron microscopy (SEM) are also studied. Banana peel is tested using gas oil, 1- and 7-day weathered Almein crude oil. The results explain that the best conditions were established at 0.3625mm particle size and temperature at 25°C for 15min.
Authors:Yasir Awais Butt Abstract: Publication date: Available online 3 June 2017 Source:Alexandria Engineering Journal Author(s): Yasir Awais Butt The problem of stabilization of a class of nonholonomic systems that can be transformed into chained form is considered. Since nonholonomic systems cannot be stabilized using smooth and time invariant control, a switching algorithm comprising three distinct steps is employed to stabilize the system. The proposed algorithm allows the system to be reduced into simpler subsystems and affords employing different controllers in each step. Using this approach, desired performance and robustness properties of the feedback control system can be guaranteed. The effectiveness of the proposed algorithm is established by applying it on a unicycle type system moving on hyperbolic plane. In order to make the controller robust, integral sliding mode control is introduced that guarantees robust stabilization. Simulation results confirm the mathematical developments.
Authors:Amir Hamzeh Haghiabi; Abbas Parsaie; Samad Ememgholizadeh Abstract: Publication date: Available online 1 June 2017 Source:Alexandria Engineering Journal Author(s): Amir Hamzeh Haghiabi, Abbas Parsaie, Samad Ememgholizadeh In this paper, the discharge coefficient of triangular labyrinth weir was predicted using multi-layer perceptron (MLP) neural network and Adaptive Neuro Fuzzy Inference System (ANFIS). To this purpose, 223 related dataset were collected. The Gamma Test (GT) was carried out to obtain the most affective parameters on the discharge coefficient. The results of the GT indicated that the ratio of length of crest of weir to the main channel width Lw/Wmc, the ratio of length of one cycle to its width (Lc/Wc) and the ratio of total upstream head flow to the weir height H/P are the most important parameters. With regarding to the results of the GT, the structure of ANFIS model was designed. The results of ANFIS model with error indices including coefficient of determination value of 0.97 and root mean square error value of 0.03 was so suitable. Comparison the results of MLP with ANFIS model showed that both models has so suitable performance however the structure of ANFIS model is more optimal.
Authors:O.A. Abegunrin; I.L. Animasaun; N. Sandeep Abstract: Publication date: Available online 1 June 2017 Source:Alexandria Engineering Journal Author(s): O.A. Abegunrin, I.L. Animasaun, N. Sandeep Bonnet of a car, the upper surface of a pointed bullet and upper surface of the pointed part of an aircraft are typical examples of an upper horizontal surface of a paraboloid of revolution (uhspr). However, the flow of some fluids past these kinds of objects fit the description of Eyring-Powell fluid flow. Theoretical investigation of two-dimensional Eyring-Powell fluid flow over such object which is neither cone/wedge nor horizontal/vertical is investigated. It is assumed that the flow of Eyring-Powell fluid is induced by catalytic surface reaction and stretching fluid layers at the free stream. The numerical solutions of the governing equation are obtained using classical fourth order Runge-Kutta scheme together with shooting techniques. The impacts of the most important parameters on the flow are presented. It is concluded that the maximum velocity of the flow is ascertained when the flow is characterized as Newtonian fluid flow. On the surface of uhspr, rapid increase and suppress in the temperature distribution and concentration with an increase in the magnitude of one of the Eyring-Powell fluid parameters are guaranteed. A significant fall in the local skin friction coefficients is ascertained due to rise in the magnitude of thickness parameter.
Authors:Zhongjin Guo; Lili Xia; Wei Zhang Abstract: Publication date: Available online 31 May 2017 Source:Alexandria Engineering Journal Author(s): Zhongjin Guo, Lili Xia, Wei Zhang In this paper, we construct a residue harmonic balance solution procedure to improve the accuracy of approximate vibration period and steady response for a strongly nonlinear oscillator from the motion of rigid rod rocking back and forth on a circular surface without slipping. In this new solution procedure, all the unbalanced residuals due to Fourier truncation are considered into next order approximation by iteration to improve the accuracy. The presented approximate analytical results are compared with the other existing solutions such as Newton harmonic balance method, variational approach method, amplitude-frequency formulation, He’s energy balance method and the exact ones which are shown in graphs. It is evident that the method considered here is quickly convergent and only the second order approximation leads to high accuracy of the steady state solutions. In addition, four numerical examples are presented to highlight the effects of system parameters on the nonlinear vibration period, and excellent agreement between approximate periods and exact ones in the steady state. It is predicted that the solution method can be found wide application in the other nonlinear oscillation problems.
Authors:Ingy El-Darwish; Mohamed Gomaa Abstract: Publication date: Available online 31 May 2017 Source:Alexandria Engineering Journal Author(s): Ingy El-Darwish, Mohamed Gomaa With the excessive energy consumption worldwide, the demand for saving strategies increases. Energy consumption in public buildings increased drastically over the last decade. Significant policy actions towards the promotion of energy-efficiency in the building sector have been developed with different intensity and structure. This study aims at proposing a retrofit strategy in an attempt to improve energy efficiency in a sample of higher educational buildings located in a hot arid climate (Egypt). Retrofitting some of the building’s envelope features can provide comfort without compromising functional needs. Comfort needs, which include thermal, visual and acoustical, can reduce energy consumption. Emphasis is placed on thermal comfort in terms of energy efficiency. Some of the important measures used in the retrofitting process of the building envelope include: external walls’ insulation, windows’ glazing type, air tightness (infiltration) and solar shading. The study results show that simple retrofit strategies such as solar shading, window glazing, air tightness then insulation can reduce energy consumption of an average of 33%. From the feasible envelope features’ used in this study, the research provides a suggestion for design codes that maintains thermal comfort, propose a feasible strategy for retrofitting and a baseline reference specifically devised for local energy efficiency.
Authors:Mohammed Abou-Galala; Mostafa Rabah; Mosbeh Kaloop; Zaki M. Zidan Abstract: Publication date: Available online 29 May 2017 Source:Alexandria Engineering Journal Author(s): Mohammed Abou-Galala, Mostafa Rabah, Mosbeh Kaloop, Zaki M. Zidan Precise Point Positioning (PPP) is a well-known positioning method that removes, models, or estimates GNSS system errors to reach the optimal position accuracy from a single receiver. The accuracy of static PPP was tested for 523 daily observation files from 75 IGS globally distributed stations observed at the period from DOY 49 to 55 in 2012. Also, the convergence period was examined to reach different levels of the horizontal accuracy to serve two applications: precision agriculture and geodetic control surveying. The accuracy of static PPP was 4, 5 and 9mm in the north, east and vertical components, respectively. Static PPP needs 60min to reach five-centimeter horizontal accuracy at the 95% confidence level and 24h to achieve one-centimeter horizontal accuracy at the 95% confidence level.
Authors:R. Ganapathy; A. Mohan Abstract: Publication date: Available online 29 May 2017 Source:Alexandria Engineering Journal Author(s): R. Ganapathy, A. Mohan Assuming the validity of the Darcy model, the steady-state development of the flow and heat transfer induced by a temperature gradient in a hemispherical porous medium with a free surface is investigated using a semi-analytical method. The streamlines are in the form of eddies with expanding vortices on either side of the axis of symmetry with the intensity of the flow field increasing with an increase in the Rayleigh number. The rate of momentum transfer is relatively higher than in a non-Darcy regime. The axial velocity is monotonic and is found to increase with an increase in the Rayleigh number. The behavior of the fluid motion on the free surface is similar to that of the axial flow. The thermal field exhibits two distinctive regions, one with a lower temperature gradient and the other with a higher but constant temperature gradient. Around the deepest end of the hemisphere, the local heat transfer rate remains unaffected by heat convection and a singularity in the graph of the Nusselt number is noticed for which a theoretical justification is given.
Authors:M. Sathish Kumar; N. Sandeep; B. Rushi Kumar; S. Saleem Abstract: Publication date: Available online 29 May 2017 Source:Alexandria Engineering Journal Author(s): M. Sathish Kumar, N. Sandeep, B. Rushi Kumar, S. Saleem Theoretical investigation is performed to discuss the heat and mass transfer behavior of chemically reacting magnetohydrodynamic Casson and Maxwell fluids past a stretching sheet with Brownian moment and thermophoresis effects with internal heat source/sink. Runge-Kutta based shooting procedure is employed to yield the solutions of the problem. Effects of the pertinent parameters on velocity, thermal and concentration boundary layers are analyzed through graphical illustrations. Also computed the reduced Nusselt and Sherwood numbers and presented through tables. It is found that the boundary layers of temperature and concentration fields are non-uniform for Casson and Maxwell fluids. Thermal and concentration fields of Maxwell fluid is highly influenced by the pertinent parameters when compared with the Casson fluid.
Authors:A.E. Geweda; M.A. El-Gohary A.M. El-Nabawy Awad Abstract: Publication date: Available online 27 May 2017 Source:Alexandria Engineering Journal Author(s): A.E. Geweda, M.A. El-Gohary, A.M. El-Nabawy, T. Awad In this paper a MATLAB SIMULINK model of seven Degrees Of Freedom (DOF) full vehicle model is developed. Mathematical equations are obtained using Newton’s second law and free body diagram concept. Validation of the SIMULINK model is obtained to ensure that the model is suitable for studying the ride comfort. A Genetic algorithm optimization technique is used to find the optimum values of spring stiffness and damping coefficient for front and rear passive suspension system of the seven DOF vehicle model at variable velocities which improve the performance of the suspension system of the vehicle. Also Proportional Integral (PI) controller is implemented to the model to study its effect on ride comfort. Comparison of the results for body acceleration and sprung mass displacement of the optimized data of suspension parameters and model with PI controller are illustrated. The results show that the optimized parameters and PI controller give significant improvements of the vehicle ride performance over the passive suspension system.
Authors:Walaa Younes El-Nashar; Ahmed Hussien Elyamany Abstract: Publication date: Available online 27 May 2017 Source:Alexandria Engineering Journal Author(s): Walaa Y. El-Nashar Drains coverings (DC) are used to pass the small discharge to function as bridge. There are two types for coverings, pipe or box type. The main problems which lead to a perceived need to cover a drain are: to minimize the adverse impact of a polluted drain, especially close to residential areas, need to use the land area occupied by the drain for an access road or some other use, poor soil stability leading to bank failure, and to protect them from pollution. DC has many effects on the environment. The main objective of this study is using value engineering (VE) to explain the effects of DC on the environment. Life cycle cost (LCC) methodology is used also to compare between two alternatives for drains. These alternatives are (i) surface drains, (ii) drains coverings. Results show that the best alternative for the environment is drains coverings.
Authors:Mohammad Tamsir; Neeraj Dhiman Vineet Srivastava Abstract: Publication date: Available online 27 May 2017 Source:Alexandria Engineering Journal Author(s): Mohammad Tamsir, Neeraj Dhiman, Vineet K. Srivastava This paper concerns through the numerical treatment of Fisher’s reaction-diffusion equation by using a hybrid numerical method. In this method, the combination of cubic trigonometric B-spline (CTB) base functions and differential quadrature method is used. This reduces the problem to a system of first order ODEs which is solved by “an optimal five stage and fourth-order strong stability preserving Runge-Kutta (SSP-RK54)” scheme. Four examples are considered to compare the present results with exact solutions and the results obtained by existing methods. It is found that the present method is not only quite easy to implement, but also it gives better results than the ones already existing in the literature.
Authors:Morteza Salehi_Panahi; Mortaza Abbaszadeh Abstract: Publication date: Available online 27 May 2017 Source:Alexandria Engineering Journal Author(s): Morteza Salehi_Panahi, Mortaza Abbaszadeh Three of the basic discussions in wireless sensor networks are routing, information exchange and lack of energy hole problem in network nodes. Considering the limitation of energy resources in these networks, the selection of an appropriate clustering method, clustering environment and proper routing has a tremendous effect on improving the efficiency of the network. Energy Hole in wireless sensor networks due to energy discharging of the nodes which are close to sink are caused because of sending its information and the further clusters from these nodes to the sink. In this article we will try to offer a method for solving this problem. By mixing some methods and utilizing of a new method. At first we will divide the network into concentric circles and each of these circles will be a layer. Then the circles will be divided into four equal parts from the largest circle. In the next step the first layer will be selected lager than the other layers and smaller than radio board and a number of sensor nodes will be placed in this layer, to reduce the extra charge from these sensors. In the next stages the life time of the network will be increased by appropriate directing and classifying to restrict of initiating energy hole.
Authors:Navdeep Singh; Irfan Haq Mir Ankush Raina Ankush Anand Vinay Abstract: Publication date: Available online 27 May 2017 Source:Alexandria Engineering Journal Author(s): Navdeep Singh, Irfan Ul Haq Mir, Ankush Raina, Ankush Anand, Vinay Kumar, Sanjay Mohan Sharma In this study, a novel self lubricating nano-composite Al-SiC-nAl2O3-WS2 has been synthesized via powder metallurgy method. Nano-Al2O3 has been prepared via combustion synthesis. Three different compositions by varying the amount of solid lubricant, WS2 (0, 5, 9) wt.% were synthesized and analyzed. The density measurements of composites were carried out by using Archimedes Principle. The micro hardness value of every composition was obtained by using micro hardness tester. The tribological properties were investigated under dry and unidirectional sliding conditions on a pin on disk tribometer. Taguchi L9 orthogonal array was used to study the effects of various parameters like load, content, speed and sliding distance on wear and frictional behavior of the composites. Analysis of variance (ANOVA) was used to investigate the percentage contribution of various parameters on the wear and friction behavior. It was observed that composite with 5wt.% of WS2 exhibited lower friction and wear. SEM images obtained therein revealed that ploughing and abrasion are the two dominant mechanisms of wear.
Authors:Amolkumar Narayan Jadhav; N. Gomathi Abstract: Publication date: Available online 26 May 2017 Source:Alexandria Engineering Journal Author(s): Amolkumar Narayan Jadhav, N. Gomathi Data present in abundance increases the complexity of handling them, which affects the effective decision-making process. Hence, data clustering gains remarkable importance in knowledge extraction and an efficient clustering method promotes the efficient decision making. Therefore, this paper proposes a method of data clustering using the WGC algorithm that determines the optimal centroid for performing the clustering process. The WGC algorithm uses the computation steps of the Whale Optimization Algorithm (WOA) with the integration of the WEGWO with a newly formulated fitness function. The WGC algorithm uses the minimum fitness measure to locate the optimal centroid and the fitness measure depends on three constraints, namely inter-cluster distance, intra-cluster distance, and the cluster density. The optimal centroid corresponding to the minimal value of the fitness is utilized for clustering the data. Experimentation is carried out using three datasets and the comparative performance analysis is carried out, which proves that the proposed WGC outperforms the existing methods. The proposed WGC attained a maximum value of F-measure, rand coefficient, and Jaccord coefficient at a rate of 0.9716, 0.9695, and 0.8949 and a minimum value of 1.463 for MSE proving that the proposed WGC algorithm outperformed the existing Particle Swarm Clustering (PSC), modified Particle Swarm Clustering (mPSC), Grey Wolf Optimization (GWO), Exponential Grey Wolf Optimization (EGWO), Kernel-based exponential grey wolf optimizer (KEGWO), and WOA.
Authors:Cleophas A. Loto Abstract: Publication date: Available online 26 May 2017 Source:Alexandria Engineering Journal Author(s): Cleophas A. Loto Electrochemical noise evaluation and statistical analysis during stress corrosion cracking (SCC) of aluminium alloy 7075-T6 has been investigated in 3.5% NaCl solution under free corrosion potential. The obtained data results were analysed using the maximum entropy method. The electrochemical noise was observed as spontaneous potential fluctuations. With all the specimens tested, a low frequency (LF) noise was obtained and it indicated characteristically LF or “flicker” noise. All the statistical parameters used in the results analysis bear close correlation with the spectral density curves/noise amplitudes. The noise generated from the corroding specimen/bulk solution interface was shown to increase with the degree of corrosion. Cracking of the specimen is indicated by the highest standard deviation peaks and the mean potentials. For this aluminium alloy, the results obtained from the electrochemical investigation and the SEM micrographs show the corrosion cracking behaviour to be consistent with the film rupture/anodic dissolution mechanism.
Authors:Samuel O. Adesanya; C.R. Makhalemele; L. Rundora Abstract: Publication date: Available online 24 May 2017 Source:Alexandria Engineering Journal Author(s): Samuel O. Adesanya, C.R. Makhalemele, L. Rundora In this paper, analysis has been conducted to investigate the effects of couple stresses and internal heat generation on the magnetohydrodynamic (MHD) natural convection channel flow with steady-periodic heat input. By applying the steady-periodic heating assumptions, the flow-governing equations driving the fluid system are reduced to boundary-value problems and solved by a convergent successive approximation. The result of the computation shows that the skin friction at the lower wall decreases with increasing values of the couple stress parameter while it enhances the heat transfer rate.
Authors:Majid Niazkar; Seied Hosein Afzali Abstract: Publication date: Available online 24 May 2017 Source:Alexandria Engineering Journal Author(s): Majid Niazkar, Seied Hosein Afzali Circular weirs have been utilized as a flow-measuring device in open channel hydraulics. Since the corresponding theoretical equation for computing discharge is not adequately suited for practical purposes due to its complexity, empirical models are utilized as a preferable alternative. In this research, new improved simple formulas for semicircular weirs with sharp and semicircular crests were proposed in favor of achieving more accurate results. These relations were obtained using a new hybrid method for an experimental database. The proposed correlations were compared with the ones in the current literature. The comparison shows that the proposed models reduce the mean absolute relative errors, MARE, by about 32% and 46% for calculating discharge with sharp and semicircular crests, respectively. Finally, the obtained results demonstrate that not only the new hybrid method is capable of rigorous calibrating process, but also the proposed models facilitate computing discharge values with more accuracy.
Authors:Sara Osama; Mohamed Elkholy; Rawya M. Kansoh Abstract: Publication date: Available online 23 May 2017 Source:Alexandria Engineering Journal Author(s): Sara Osama, Mohamed Elkholy, Rawya M. Kansoh Continuous increase of population in Egypt, limited fresh water, poor maintenance and low efficiency of irrigation systems lead to a real burden on the Egyptian natural water resources. Accordingly, for Egypt, land and water resources management is considered an absolutely strategic priority. In this study, a linear optimization model is developed to maximize the net annual return from the three old regions of Egypt. Data for 28 crops in five years from 2008 to 2012 are being analyzed. The spatial variations of crops, irrigation water needs, crop yields and food requirements are incorporated in the model. The results show that there is a significant reduction in the allocated areas for onion, garlic, barley, flax, fenugreek, chickpeas, lentil and lupine since they are considered as non-strategic crops. On the other side, the allocated areas for strategic crops such as wheat, maize, clover, rice, sugar products and cotton remained almost the same to satisfy their actual food requirements. However, crops with high net returns such as tomatoes have increased substantially. The trend for the gross net benefit is decreasing and is expected to reach a lower value in year 2017. Different approaches and scenarios are analyzed. The developed model proposes a change in the cropping pattern in the old lands of Egypt to increase the gross net return without adding further any other expenses.
Authors:Mounir Mahmoud Moghazy Abdel-Aal Abstract: Publication date: Available online 20 May 2017 Source:Alexandria Engineering Journal Author(s): Mounir Mahmoud Moghazy Abdel-Aal In the travel demand modeling field, mode choice is the most important decision that affects the resulted road congestion. The behavioral nature of the disaggregate models and the associated advantages of such models over aggregate models have led to their extensive use. This paper proposes a framework to determine the value of time (VoT) for the city of Alexandria through calibrating a disaggregate linear-in parameter utility-based binary logit mode choice model of the city. The mode attributes (travel time and travel cost) along with traveler attributes (car ownership and income) were selected as the utility attributes of the basic model formulation which included 5 models. Three additional alternative utility formulations based on the transformation of the mode attributes including relative travel cost (cost divided by income) and log (travel time) and the combination of the two transformations together were introduced. The parameter estimation procedure was based on the likelihood maximization technique and was performed in EXCEL. Out of 20 models estimated, only 2 models are considered successful in terms of the parameters estimates correct signs and the magnitude of their significance (t-statistics value). The determination of the VoT serves also in the model validation. The best two models estimated the value of time at LE 11.30/hr and LE 14.50/hr with a relative error of +3.7% and +33.0%, respectively, of the hourly salary of LE 10.9/hr. The proposed two models prove to be sensitive to trip time and income levels as factors affecting the choice mechanism. The sensitivity analysis was performed and proved the model with higher relative error is marginally more robust.
Authors:Ahmed Al-Samari Abstract: Publication date: Available online 20 May 2017 Source:Alexandria Engineering Journal Author(s): Ahmed Al-Samari Parallel hybrid electric vehicles (PHEVs) increasing rapidly in the automobile markets. However, the benefits out of using this kind of vehicles are still concerned a lot of costumers. This work investigated the expected benefits (such as decreasing emissions and increasing fuel economy) from usingthe parallel HEV in comparison to the conventional vehicle modelofthe real-worldand standard driving cycles. The software Autonomie used in this study to simulate the parallel HEV and conventional models on these driving cycles. The results show that the fuel economy (FE) can be improved significantly up to 68% on real-world driving cycle, which is representedmostly city activities. However, the FE improvement was limited (10%) on the highway driving cycle, and this is expected since the using of brake system was infrequent. Moreover, the emissions from parallel HEV decreased about 40% on the real-world driving cycle, and decreased 11% on the highway driving cycle. Finally, the engineefficiency, improvedabout 12% on the real-world driving cycle, and about 7% on highway driving cycle.
Authors:Mohamed M. Hassan; Mohamed A. Teamah; Wael M. El-Maghlany Abstract: Publication date: Available online 19 May 2017 Source:Alexandria Engineering Journal Author(s): Mohamed M. Hassan, Mohamed A. Teamah, Wael M. El-Maghlany Impinging jet is one of various methods of cooling with the ability to achieve high heat transfer rates and improve average surface’s Nusselt number. This method has vast industrial applications including integrated use in solar collectors, gas turbine cooling, refrigeration, air conditioning and electronics cooling. A numerical study is conducted to study the effects of using nanofluids on impinging slot jet over a flat plate with a ribbed surface. The main objective of the study was to investigate the possibility of improving the overall heat transfer rate by focusing on the improvements in the local and average surface Nusselt number values. Several parameters effects are studied including Solid Volume Fraction, Richardson number and Reynolds number. These results indicated a marked improvement in average Nusselt number with the increase in the solid volume fraction. Also, there is an amended value when the buoyancy effect is dominant over the whole domain. The results are shown in the form of streamlines, isotherms and Nusselt numbers contra other variables. The current work was simulated using a FORTRAN CFD Code, which discretizes the non-dimensional forms of the governing equations utilizing the finite volume method and solving the consequent algebraic equations using Gauss-Seidel method Utilizing TDMA.
Authors:J. Dhalia Sweetlin; H. Khanna Nehemiah; A. Kannan Abstract: Publication date: Available online 17 May 2017 Source:Alexandria Engineering Journal Author(s): J. Dhalia Sweetlin, H. Khanna Nehemiah, A. Kannan Background Computer-aided diagnosis (CAD) systems for the detection of lung disorders play an important role in clinical decision making. CAD systems provide a second opinion to the physician in interpreting computed tomography (CT) images. In this work, a CAD system to diagnose pulmonary hamartoma nodules from chest CT images is proposed. Methods Segmentation of lung parenchyma from CT images is carried out using Otsu’s thresholding method. Nodules are considered to be the region of interests (ROIs) in this work. Texture, shape and run length based features are extracted from the ROIs. Cosine similarity measure (CSM) and rough dependency measure (RDM) are used independently as filter evaluation functions with ant colony optimization (ACO) to select two subsets of features. The selected subsets are used to train two classifiers namely support vector machine (SVM) and Naive Bayes (NB) classifiers using 10-fold cross validation. All the four trained classifiers are tested and the performance measures are estimated. Results CT slices of patients affected with pulmonary cancer and hamartoma are used for experimentation. From the lung parenchymal tissues of 300 CT slices, 390 nodules are extracted. The feature selection algorithms, ACO-CSM and ACO-RDM are run for different feature subset sizes. The selected features are used to train SVM and NB classifiers. From the results obtained, it is inferred that SVM classifier with the feature subsets chosen by ACO-RDM feature selection approach yielded a maximum classification accuracy of 94.36% with 38 features. Conclusion From the results, it can be clearly inferred that selecting relevant features to train the classifier has a definite impact on the performance of the classifier.
Authors:Abdulsalam A. Fadhil; Magdy S. Ghattas; Berlanty A. Iskander; Sami A. Ajeel; Tawakol A. Enab Abstract: Publication date: Available online 17 May 2017 Source:Alexandria Engineering Journal Author(s): Abdulsalam A. Fadhil, Magdy S. Ghattas, Berlanty A. Iskander, Sami A. Ajeel, Tawakol A. Enab The structure of leaded brass alloy used for gas valves production is studied. Some scientific knowledge and facts about this subject are introduced. The melting and casting of leaded brass billets, hot extrusion with cold drawing of rods and hot forging of gas valves are performed. Some changes in production parameters are performed and 30% of pure materials added to improve the final products and minimize the defects. The structure of alloy is studied using optical and SEM/EDS devices for inspections. Radiographic and ultrasonic tests are used to detect the cracks and other defects in final products. The results indicated that the structures, phase distribution and the quality of leaded brass alloys differ slightly during casting, extrusion and hot forging processes. Also, most of samples consist of α and β phases with lead particles distributed on the grain boundaries or inside these phases. Very small crack is appeared in one sample of the forged gas valve, while the other valves are free. Improving the production parameters and also using of pure materials in charge elements are contributed by result improvement. SEM/EDS investigation results confirm the microstructure results of optical microscope for sample element distribution.
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