Authors:Ahmed Ali El Adoly; Mohamed Gheith; M. Nashat Fors Abstract: Publication date: Available online 12 February 2018 Source:Alexandria Engineering Journal Author(s): Ahmed Ali El Adoly, Mohamed Gheith, M. Nashat Fors Nurse Scheduling Problem (NSP) is the assignment of a number of nurses to a number of shifts in order to satisfy hospital’s demand. The objectives of NSP are the minimization of the overall hospital cost, and the maximization of nurses’ preferences while taking into consideration the governmental rules and hospital standards. In this article, a proposed mathematical model for the NSP is presented, which is based on the idea of multi-commodity network flow model. The proposed model was verified using hypothetical instances as well as benchmark instances, then, it is applied to a real case study in an Egyptian hospital. The results demonstrate the advantage of using the proposed model in generating schedule required to solve the problem. Furthermore, it proves the superiority of the obtained schedule to those generated manually by the supervisor head nurse as it improves the level of nurses’ satisfaction by creating fair schedule system take care about nurses’ preferences as well as decreases the overall overtime cost by 36%.
Authors:Ramesh Babu Vallabhaneni; V. Rajesh Abstract: Publication date: Available online 1 February 2018 Source:Alexandria Engineering Journal Author(s): Ramesh Babu Vallabhaneni, V. Rajesh The paper presents an automatic brain tumour detection technique in noise corrupted images. The Denoising of the image is implemented using Edge Adaptive Total Variation Denoising Technique (EATVD). The technique is used to preserve the edges in the process of Denoising image. Once the noise is removed from the image, the image is segmented using mean shift clustering. The segmented parts are sent to gray level co-occurrence matrix for feature extraction. The features are used by multi class SVM to detect the tumour in the images. The step followed extracts the tumour with increased precision in noisy images.
Authors:A. Abd_Elsalam; M.A. Gohary; H.A. El-Gamal Pages: 345 - 357 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): A. Abd_Elsalam, M.A. Gohary, H.A. El-Gamal This paper presents experimental modal analysis of non-rotating tires under different boundary conditions. A test rig with four guides in vertical (radial) direction and two guides in axial direction was designed to support the tire-rim assembly with a free support. The setup permits to carry out the experiments on the grounded supported tire-rim assembly while changing the value of the static load acting on the wheel axis. Under static load condition, it is found that, tire deflection depends on the applied static radial force in a hysteresis manner and a third-order polynomial was used to fit the data during loading and unloading conditions. The relationship between static stiffness in radial direction and tire deflection is nonlinear and depends on loading/unloading conditions for different tire pressures. The response of the tire is quite similar to the response of viscously damped mass system for impulse force which is provided by an impact hammer. The results show that the system modal parameters can be obtained respective of loading or unloading conditions with a maximum difference of 1.992% for frequency values and 3.66% for damping values. This study has a practical value for the description of mechanical properties of tires.
Authors:Mahmoud Omar; M.M. El-kassaby; Walid Abdelghaffar Pages: 359 - 370 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Mahmoud Omar, M.M. El-kassaby, Walid Abdelghaffar A fully active electro-hydraulic and passive automotive quarter car suspensions with their experimental test-rigs are designed and implemented. Investigation of the active performance compared against the passive is performed experimentally and numerically utilizing SIMULINK's Simscape library. Both systems are modeled as single-degree-of-freedom in order to simplify the validation process. Economic considerations were considered during the rig's implementation. The rig consists of two identical platforms fixed side by side allowing testing two independent suspensions simultaneously. Position sensors for sprung and unsprung masses on both platforms are installed. The road input is introduced by a cam and a roller follower mechanism driven by 1.12kW single phase induction motor with speed reduction assembly. The active hydraulic cylinder was the most viable choice due to its high power-to-weight ratio. The active control is of the proportional-integral-differential (PID) type. Though this technique is quite simple and not new, yet the emphasis of this paper is the engineering, design and implementation of the experimental setup and controller. A successful validation process is performed. Ride comfort significantly improved with active suspension, as shown by the results; 24.8% sprung mass vibration attenuation is achieved. The details of the developed system with the analytical and experimental results are presented.
Authors:I.M. El-Galy; M.H. Ahmed; B.I. Bassiouny Pages: 371 - 381 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): I.M. El-Galy, M.H. Ahmed, B.I. Bassiouny The design of metal matrix composites can be enhanced by integrating the concept of functionally graded materials (FGM) to produce engineering materials with tailored contradictory properties that suit multifunctioning components. The present investigation focuses on characterization of functionally graded metal matrix composites (FGMMCs) based on pure aluminium matrix reinforced with different percentages and sizes of SiC particles. The investigated FGMs have been produced by horizontal centrifugal casting process under different conditions. Microstructure investigation, tensile, hardness and wear rate measurements have been correlated with the size and percentage of SiC particles and their distribution/gradient across the thickness of the cast tubes resulting from the used casting parameters.
Authors:Ossama Mokhiamar; Semaan Amine Pages: 383 - 394 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Ossama Mokhiamar, Semaan Amine This paper introduces a control system to stabilize the motion of skid steering vehicles, extends their stability limit and makes their handling performance similar to that of the conventional two-wheel steering vehicle. For this purpose, the yaw rate response of the two degree of freedom (2DOF) linear model of the conventional two-wheel steering vehicle is chosen as a model response. The model following control theory is used to introduce the direct yaw moment needed to stabilize and steer the skid steering vehicle. The direct yaw moment has been split into the four tires based on two methods. The first method is based on a simple distribution technique (SD), whereas the second method is based on an independent distribution technique (ID) where the four wheels can be driven individually using a full drive-by-wire system. A comprehensive nonlinear dynamic model of the skid steering vehicle has been simulated using Matlab/Simulink in order to examine the effectiveness of the proposed control system. The results of both open and closed loop tests show that the proposed control system has a significant effect on stabilizing the lateral motion of skid steering vehicles as well as improving their handling characteristics.
Authors:A.E. Kabeel; Mohamed Abdelgaied; Ravishankar Sathyamurthy; T. Arunkumar Pages: 395 - 403 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): A.E. Kabeel, Mohamed Abdelgaied, Ravishankar Sathyamurthy, T. Arunkumar In the present paper, the effects of the indirect evaporative cooler with internal baffle on the performance of the hybrid air conditioning system are numerically investigated. The hybrid air conditioning system contains two indirect evaporative coolers with internal baffle, one is utilized to pre-cool the air inlet to the desiccant wheel and the other is utilized to pre-cool the supply air inlet to the room. The effects of the inlet conditions of the process and reactivation air and working air ratio on the thermal performance of the hybrid air conditioning system have been analyzed. The results of this study show that in the hybrid air conditioning system for using the indirect evaporative cooler with internal baffle as a pre-cooling unit, the supply air temperature reduced by 21% and the coefficient of performance improved by 71% as compared to previous designs of the hybrid air conditioning system at the same inlet conditions. For increasing process air inlet temperature from 25°C to 45°C, supply air temperature increases from 12.7°C to 14.2°C, thermal COP increases from 1.87 to 2.84, and supply air relative humidity increases from 76.7% to 77.4%. Also, for increasing the reactivation air inlet temperature from 70°C to 110°C, supply air temperature dropped from 15.9°C to 10.9°C, supply air relative humidity dropped from 82.7% to 71.8%, and thermal COP dropped from 4.5 to 1.7. The recommended optimal air working ratio in the indirect evaporative cooler with internal baffle should be 0.15.
Authors:A.E. Geweda; M.A. El-Gohary; A.M. El-Nabawy; T. Awad Pages: 405 - 414 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 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:A.KH. EL-Said; B.M. EL-Souhily; W.A. Crosby; H.A. EL-Gamal Pages: 423 - 432 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): A.KH. EL-Said, B.M. EL-Souhily, W.A. Crosby, H.A. EL-Gamal The present research work deals with studying the steady state performance and dynamic stability of sliding element hydrodynamic bearings of the three-lobe type and provided with a bushing surface textured with uniform micro protrusions. A mathematical model has been put forward for the problem using the Reynolds equation governing the unstable fluid lubrication inside the bearing as well as the equations governing the dynamic movement of the journal. The equations have been put in their numerical forms suitable for computer solution using the finite difference method. Two types of three lobe bearings have been considered, one with its plain bushing and the other with bushing textured with uniform micro protrusions. This is in addition to other two plain journal bearings one with plain bushing and the other with textured bushing. This is for the purpose of carrying out a general comparison to include the steady performance of these bearings in terms of their load carrying capacity and the friction losses in their parts in addition to their dynamic stability. It was concluded in the present work that the inclusion of these textured micro protrusions in the bushing of bearings, whether they are plain or of the three-lobe geometry improves their performance in terms of reducing their friction losses and raising their load carrying capacity along. It was found that the three-lobe bearing with protruded bushing surface texture is superior to the other types of bearings considered in the present work as far as steady state performance is concerned. Regarding the margin of stability to small sinusoidal disturbances the protruded three-lobe bearing shows a relatively lower margin. Some useful recommendations for future research work in this field of study are given in this work and the most important one is to carry out extensive experimental studies on sliding bearings surfaces fitted with textured bushings of different micro protrusions designs.
Authors:Mohamed M.Y.B. Elshabasy; Khaled T. Mohamed; Atef A. Ata Pages: 439 - 447 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Mohamed M.Y.B. Elshabasy, Khaled T. Mohamed, Atef A. Ata Optimum trajectory planning for a planar redundant manipulator which consumes minimum power is considered in this paper. The equations of motion for the manipulator are derived in matrix form using Lagrange Equation. Two hybrid optimization algorithms with constrained variables during the search have been presented and compared to design an optimal trajectory for planar redundant manipulator based on minimum power to be consumed. Two trajectories with the same initial angular displacement of the manipulator joints and two different angular positions at the end of the trajectories are studied. Both the hybrid technique of the Genetic Algorithm (GA) and the constrained Fmin function (GA-Fmincon) and the hybrid genetic algorithm with the pattern search (GA-PS) subjected to the same constraints give the same results for the trajectory that ends with angular displacements of (π/2,0,0)rad with trivial differences in the power values at any arbitrary mission period. For the second trajectory, which ends with angular positions of (1,1,1)rad, the GA-PS gives a penalty function of smaller value.
Authors:Mazhar B. Tayel; M.A. Massoud; Y. Farouk Pages: 449 - 457 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Mazhar B. Tayel, M.A. Massoud, Y. Farouk Coronary heart diseases are ranked as the top diseases causing death in many countries worldwide. Intravascular Ultrasound (IVUS) directly images the vessel from inside and allows the extraction of vessel bounders and the measurement of vessel cross-sectional area. This paper introduces an approach for detection of lumen and media-adventitia borders in an Intravascular (IV) image. In the proposed method, a modified fast algorithm is applied to determine the lumen and media-adventitia contours. The modified fast algorithm is fully tested and it showed an improvement in speed of up to 200% while preserving an accuracy rate of 98%.
Authors:Rana Elgendy; Amr Morad; Hicham G. Elmongui; Ayman Khalafallah; Mohamed S. Abougabal Pages: 459 - 468 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Rana Elgendy, Amr Morad, Hicham G. Elmongui, Ayman Khalafallah, Mohamed S. Abougabal Privacy becomes a major concern for both consumers and enterprises; therefore many research efforts have been devoted to the development of privacy preserving technology. The challenge in data privacy is to share the data while assuring the protection of personal information. Data privacy includes assuring protection for both insider ad outsider threats even if the data is published. Access control can help to protect the data from outsider threats. Access control is defined as the process of mediating every request to resources and data maintained by a system and determining whether the request should be granted or denied. This can be enforced by a mechanism implementing regulations established by a security policy. In this paper, we present privacy preserving data publishing model based on integration of CPBAC, MD-TRBAC, PBFW, protection against database administrator technique inspired from oracle vault technique and benefits of anonymization technique to protect data when being published using k-anonymity. The proposed model meets the requirements of workflow and non-workflow system in enterprise environment. It is based on the characteristics of the conditional purposes, conditional roles, tasks, and policies. It guarantees the protection against insider threats such as database administrator. Finally it assures needed protection in case of publishing the data.
Authors:Nehal M. El Azaly; Ehab F. Badran; M.R.M. Rizk; M. Amr Mokhtar Pages: 469 - 475 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Nehal M. El Azaly, Ehab F. Badran, M.R.M. Rizk, M. Amr Mokhtar Cognitive radio wireless networks CRNs have been considered as an efficient communication paradigm to the utilization of scarce spectrum. The main purpose of channel reservation of dynamic spectrum access (DSA) is to access these idle channels intelligently which are specialized for primary users (PUS) to be used by unlicensed users temporarily, which are called secondary users (SUS) without causing critical interference to the licensed user’s activity. In this paper, continuous-time Markov chain paradigm is improved via channel reservation to show the best usage of the radio spectrum bands, and the transition matrix are deduced for the proposed model. Moreover, the probability state vector is proved by performing steady state analysis. The deduced expressions of the suggested model are illustrated in the numerical results section.
Authors:V.N.V. Satya Prakash; K. Satya Prasad; T. Jaya Chandra Prasad Pages: 477 - 483 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): V.N.V. Satya Prakash, K. Satya Prasad, T. Jaya Chandra Prasad Images contain three primary colors at each pixel, but single sensor digital cameras capture only one of the primary channels. Process of color image reconstruction by finding the missing color component is called color image demosaicing. Various approaches have been proposed in this field of image demosaicing such as interpolation based and frequency based approaches due to sharp image edge and higher color saturation, and these techniques fail to reconstruct image efficiently. To overcome this, in this work we propose a new approach, sparse based RBF network for color image demosaicing. According to this approach a sparse model is constructed first and based on that weights are computed which are used to minimize the reconstruction error. To improve this we use optimal weight computation and RBF training for missing color component value prediction. Proposed method is implemented using MATLAB tool and experimental results show the efficiency of the proposed work in terms of color peak signal to noise ratio (CPSNR). Simulation results show 16.20% improvement in the performance in terms of CPSNR.
Authors:Kasiprasad Mannepalli; Panyam Narahari Sastry; Maloji Suman Pages: 485 - 497 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Kasiprasad Mannepalli, Panyam Narahari Sastry, Maloji Suman Due to the rapid development of human computer interaction systems, the recognition of emotion becomes a challenging task. Various handheld devices such as smart phones and PCs are utilized to recognize the human emotion from the speech. But, the recognition of emotion is burdensome to the human computer interaction system since it differs according to the speaker. To resolve this problem, the Adaptive Fractional Deep Belief Network (AFDBN) is proposed in this paper. Initially, the spectral features are extracted from the input speech signal. The features obtained are the tonal power ratio, spectral flux, pitch chroma and MFCC. The extracted feature set is then given into the network for the classification. Thus, the AFDBN is newly designed by the fractional theory and Deep belief network. Then, the proposed AFDBN method is used to find out the optimal weights which are used to recognize the emotion efficiently. Finally, the experimental results are evaluated and its performance is analyzed by the evaluation metrics which is compared with the existing systems. The outcome of the proposed method attains 99.17% accuracy for Berlin database and 97.74% for Telugu database.
Authors:D.B. Prakash; C. Lakshminarayana Pages: 499 - 509 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): D.B. Prakash, C. Lakshminarayana In present days, continuous effort is being made in bringing down the line losses of the electrical distribution networks. Therefore proper allocation of capacitors is of utmost importance because, it will help in reducing the line losses and maintaining the bus voltage. This in turn results in improving the stability and reliability of the system. In this paper Whale Optimization Algorithm (WOA) is used to find optimal sizing and placement of capacitors for a typical radial distribution system. Multi objectives such as operating cost reduction and power loss minimization with inequality constraints on voltage limits are considered and the proposed algorithm is validated by applying it on standard radial systems: IEEE-34 bus and IEEE-85 bus radial distribution test systems. The results obtained are compared with those of existing algorithms. The results show that the proposed algorithm is more effective in bringing down the operating costs and in maintaining better voltage profile.
Authors:Laila Elhifnawy; Hamdy Abou-Elfath; Emad El-Hout Pages: 511 - 522 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Laila Elhifnawy, Hamdy Abou-Elfath, Emad El-Hout The inelastic behavioral characteristics of three RC buildings having 6-, 10- and 20-stories under near-source multi-component earthquake excitations are investigated. Ten earthquake records are used in the analysis to cover a wide range of vertical to horizontal spectral ratios. The performances of the buildings are evaluated through the roof displacements, the maximum story drift ratios and the maximum axial forces and strain ductility factors in the building members. Four analysis cases are considered for each earthquake including, one lateral earthquake component (X-case), two lateral earthquake components (XY-case), one lateral earthquake component accompanied with the vertical earthquake component (XZ-case) and two lateral earthquake components accompanied with the vertical earthquake component (XYZ-case). The results obtained in this study indicate that the multi-component effect of the earthquakes has a considerable effect on the axial forces and strain ductility factors of the building columns although it does not significantly affect the building lateral-deformation response.
Authors:Mahmoud Abu Yaman; Metwally Abd Elaty; Mohamed Taman Pages: 523 - 532 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Mahmoud Abu Yaman, Metwally Abd Elaty, Mohamed Taman Self compacting concrete (SCC) is a highly flowable type of concrete that spreads into form without the need of mechanical vibration. This paper presents a comparative study between two methodologies which have been applied on two different data sets of SCC mixtures, which were gathered from the literature, using artificial neural network (ANN). The two methodologies aim to get the best prediction accuracy for the SCC ingredients using the 28-day compressive strength and slump flow diameters as inputs of the ANN. In the first methodology, the ANN model is constructed as a multi input – multi output neural network with the six ingredients as outputs. In the second methodology, the ANN model is constructed as a multi input – single output neural network where the six ingredient outputs are predicted separately from six different neural networks of multi input – single output type. Also, the influence of the mixes homogeneity on the prediction accuracy is investigated through the second data set. The results demonstrate the superiority of the second methodology in terms of accuracy of the predicted outputs. Moreover, the uniformity of the training data assures the accuracy of the predicted ingredients.
Authors:Asmaa Barakat; Hany Ayad; Zeyad El-Sayed Pages: 533 - 543 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Asmaa Barakat, Hany Ayad, Zeyad El-Sayed Improving outdoor human thermal comfort could be considered as one of the most important targets for achieving successful open space designs. In hot arid climate, residential neighborhoods are responsible for the high request of energy to provide cooling needs for the occupants’ comfort. The main problem is the non-responsive contemporary urban design to human thermal comfort and energy. In this context, this paper aims at testing specific landscape parameters that could enhance outdoor human thermal comfort. The study is limited to the microclimate at urban open space and will be conducted in New Borg El-Arab (hot arid city according to Middleton and others [1], Alexandria, Egypt). The adopted methodology is based on the use of ENVI-met 4.0 software to measure four thermal indices (air temperature, relative humidity, MRT and PMV) and assess outdoor human thermal comfort in an existing neighborhood. In addition, different design scenarios that emphasize different landscape elements were also assessed. The results of this analysis depict changing street networks, landscape design and materials could enhance the level of thermal comfort in the urban open spaces.
Authors:Sara Osama; Mohamed Elkholy; Rawya M. Kansoh Pages: 557 - 566 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 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 Pages: 567 - 578 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 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:Ingy El-Darwish; Mohamed Gomaa Pages: 579 - 589 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 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:Rasha T.S. Mabrouk; Amr Bakr; Hany Abdalla Pages: 591 - 599 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 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:Nourhan Samir; Rawya Kansoh; Walid Elbarki; Amr Fleifle Pages: 601 - 612 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Nourhan Samir, Rawya Kansoh, Walid Elbarki, Amr Fleifle In the last decades water resources availability has been a major issue on the international agenda. In a situation of worsening scarcity of water resources and the rapidly increasing of water demands, the state of water losses management is part of man’s survival on earth. Leakage in water supply networks makes up a significant amount, sometimes more than 70% of the total water losses. The best practices suggest that pressure management is one of the most effective way to reduce the amount of leakage in a water distribution system. The approach presented in this study is aimed at modeling leakage as a function of pressure and pipe length, calibrating leakage coefficient, using fixed pressure reducing valves (PRVs) to develop pressure fluctuation and developing WaterCAD scenarios to minimize leakage through the most effective settings of PRVs. This approach was applied on a district metered area (DMA) in Alexandria, Egypt. The application of this approach produced some encouraging results, where the leakage through DMA was dropped by 37% for the best scenario. Thus, this approach is recommended as a decision support tool for determining a desirable solution for leakage reduction.
Authors:J. Rahimi; D.D. Ganji; M. Khaki; Kh. Hosseinzadeh Pages: 621 - 627 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): J. Rahimi, D.D. Ganji, M. Khaki, Kh. Hosseinzadeh The aim of this article was to apply collocation method for boundary layer flow of an Eyring-Powell fluid over a stretching sheet in unbounded domain. The collocation method combined with a special technique, has been successfully applied for nonlinear equations of momentum with infinite boundary values. The solution for velocity is computed by applying the collocation method. The governing nonlinear differential equations are reduced to the ordinary differential equations by similarity transformations. The physical significance of different parameters on the velocity profile is discussed through graphical illustrations. It is noticed that the velocity increases by increasing the Eyring-Powell fluid material parameter (ε) whereas it decreases by increasing the fluid material parameter (δ).
Authors:Md. Mahtab Hossain Mondal; Md. Helal Uddin Molla; Md. Abdur Razzak; M.S. Alam Pages: 629 - 634 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Md. Mahtab Hossain Mondal, Md. Helal Uddin Molla, Md. Abdur Razzak, M.S. Alam In this paper, a new analytical approach based on harmonic balance method (HBM) is presented to obtain the approximate periods and the corresponding periodic solutions of quadratic nonlinear oscillators. The result obtained in new approach has been compared with that obtained by other existing method. The present method gives not only better result than other existing result but also gives very close to the corresponding numerical result (considered to be the exact result). Moreover, the method is simple and straightforward.
Authors:M. Sheikholeslami; D.D. Ganji Pages: 635 - 645 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): M. Sheikholeslami, D.D. Ganji Influence of adding CuO nanoparticles in the base fluid on flow and heat transfer in an inclined half-annulus was studied considering constant heat flux as boundary condition of hot wall. Control Volume based Finite Element Method (CVFEM) is applied in order to simulate procedure. Pressure gradient source terms are eliminated by using vorticity stream function formulation. Influences of CuO volume fraction, inclination angle and Rayleigh number on hydrothermal manners are presented. Results indicate that inclination angle makes changes in flow style. The strength of eddies reaches to its minimum value when the upper wall is hot. Temperature gradient enhances with rise of buoyancy forces while it reduces with augment of inclination angle.
Authors:M. Jayachandra Babu; N. Sandeep; S. Saleem Pages: 659 - 669 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): M. Jayachandra Babu, N. Sandeep, S. Saleem The knowledge of heat and mass transfer of MHD flows over different geometries is very important for heat exchangers design, transpiration, fiber coating, etc. With this initiation, a mathematical model is proposed to investigate the two-dimensional flow, heat and mass transfer of magnetohydrodynamic flow over three different geometries (vertical cone, vertical wedge, and a vertical plate). Cattaneo-Christov heat flux with external magnetic field, thermophoresis and Brownian movement effect are introduced in the model. Runge-Kutta and Newton’s methods are employed to solve the altered governing nonlinear equations. The influences of the parameters of concern on the common profiles (velocity, temperature, and concentration) are conversed (in three cases). By viewing the same parameters, skin friction coefficient, heat and mass transfer rates are discussed with the assistance of tables. It is discovered that the momentum and thermal boundary layers are non-uniform for the MHD flow over three geometries (vertical cone, wedge, and a plate). Thermal and solutal Grashof numbers regulate the temperature and concentration fields. The heat and mass transfer rates of the flow over a cone are highly influenced by the thermal relaxation parameter.
Authors:Alok Kumar Pandey; Manoj Kumar Pages: 671 - 677 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Alok Kumar Pandey, Manoj Kumar Investigation of heat transfer effect on Cu-water nanofluid flow past a stretching cylinder is focused in the recent article. The numerical method of nonlinear known as RKF 4–5th has been taken into account along with shooting process to obtain the solution of required ODEs with supplementary boundary conditions. The influence of thermal radiation parameter on non-dimensional skin friction and Nusselt number along with convection parameter, solid particle volume fraction and heat generation/absorption parameter are represented in the tabular and graphical way. The volume fraction of nanofluid is considered as 0–6% with an increment of 2%. The thermal radiation parameter lies in the domain of [ 0.3 , 5 ] . Moreover, the values of porosity parameter ( λ ) and heat generation/absorption parameter (Q) are varied as 0.5 ⩽ λ ⩽ 2.5 and - 2 ⩽ Q ⩽ 2 , respectively. The data of authors declared that augmentation is perceived in temperature curves with the volume fraction of solid particles; moreover, momentum boundary layer depreciates with boost in volume fraction parameter of copper (Cu) particles. The obtained data are distinguished with earlier study and admirable agreement has been noted.
Authors:P. Aparna; N. Pothanna; J.V. Ramana Murthy; K. Sreelatha Pages: 679 - 685 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): P. Aparna, N. Pothanna, J.V. Ramana Murthy, K. Sreelatha The analytical study of the flow generated by the slow steady rotation of a permeable sphere in an incompressible micro-polar fluid is considered. Both the flows internal and external to the sphere are coupled. The result will degenerate to independent equations for the case of viscous fluids for the inner and external flows. The flow field in the form of velocity w and micro rotation function φ are obtained in terms of modified Bessel functions and Gegenbauer polynomials. The flow pattern is shown in the form of graphs. It is interesting to note that the velocity and micro-rotation functions within the sphere are constant at distances from the axis of rotation since it represents a rigid body rotation. Effects of physical parameters on the Couple are also shown in the form of graphs.
Authors:K. Karimi; H. Roohani Ghehsareh; K. Sadeghi Pages: 687 - 694 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): K. Karimi, H. Roohani Ghehsareh, K. Sadeghi Solutions for the magnetohydrodynamic nano boundary layer fluid flow over a permeable stretching surface embedded in a porous medium are obtained numerically by rational Legendre collocation method. Two-dimensional and axisymmetric flows induced by stretching of the surface are considered. The effects of magnetic parameter, the porous parameter, first and second order slip and suction/injection parameters on the flow are discussed. A comparison of numerical results with previous published results is made and the results are found to be in good agreement.
Authors:Dalia M. El-Gazzar Pages: 695 - 707 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Dalia M. El-Gazzar The main objective of this research was to evaluate and enhance dynamic performance for a vertical pumping unit. The original electric motor of the pump unit had been replaced by another one different in design and weights. Vibration has been increased greatly after installing the new motor. Consequently, it is necessary to estimate the change in the vibration characteristics owing to the difference in the boundary conditions of the new motor. Measured vibration levels and frequency analysis were dangerous at 1× due to resonance problem. Finite Element Analysis was used to model the motor structure in order to find its natural frequencies and mode shapes. The results confirm that the third natural frequency is very close to 1× operating speed with deviation about 1%. To solve the resonance problem, it was recommended to increase the structure stiffness. The results after modifications confirmed that the overall vibration level decreases by 89%.
Authors:Ahmed Al-Samari Pages: 721 - 726 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 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:Amir Reza Mahmoudi; Iman Khazaee; Mohsen Ghazikhani Pages: 737 - 748 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Amir Reza Mahmoudi, Iman Khazaee, Mohsen Ghazikhani The main objective of this work was to respond to the global concern for the rise of the emissions and the necessity of preventing them to form rather than dealing with their after-effects. Therefore, the production levels of four main emissions, namely NOx, CO2, CO and UHC in gasoline engine of Nissan Maxima 1994 is assessed via 1-D simulation with the GT-Power code. Then, a proper matching of turbine-compressor is carried out to propose a turbocharger for the engine, and the resultant emissions are compared to the naturally aspirated engine. It is found that the emission levels of NOx, CO, and CO2 are higher in terms of their concentration in the exhaust fume of the turbocharged engine, in comparison with the naturally aspirated engine. However, at the same time, the brake power and the brake specific emissions produced by the turbocharged engine are respectively higher and lower than those of the naturally aspirated engine. Therefore, it is concluded that, for a specific application, turbocharging provides the chance to achieve the performance of a potential naturally aspirated engine while producing lower emissions.
Authors:Ola Abdelwahab; Samir M. Nasr; Walaa M. Thabet Pages: 749 - 755 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 Author(s): Ola Abdelwahab, Samir M. Nasr, Walaa M. Thabet The cleanup of oil spill using natural adsorbents is considered as an eco-friendly and cost-effective way, emphasizing the importance of such natural and effective promising technique. Palm fibers, PFs, were used as natural sorbent material for oil spill removal. The present study examines the sorption efficiency and capacity of raw and modified fibers for three types of oil: diesel oil, crude oil and vegetable oil. The results revealed that the efficiency of fibers to remove different types of oil from artificial saline water was related to sorption time and the system conditions such as oil film thickness, particle size, sorbent dosage and temperature. The results showed high sorption efficiency and capacity of palm fibers for different kinds of oil. PFs were very proved to be promising fibers because of all advantages of agricultural wastes plus the high resistance of that fibers which appeared obviously in the present study.
Authors:Magdi El-Messiry; Shaimaa El-Tarfawy; Rania El Deeb Pages: 297 - 307 Abstract: Publication date: December 2017 Source:Alexandria Engineering Journal, Volume 56, Issue 4 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:B. Samuyelu; P. Rajesh Kumar Abstract: Publication date: Available online 9 November 2017 Source:Alexandria Engineering Journal Author(s): B. Samuyelu, P. Rajesh Kumar This paper extends the adaptive normalized sub-band adaptive filtering (NSAF) by introducing variable error bound and memorizing the error convergence. The variable error bound attempts to vary the updating point of the filter coefficients. The error memory aids in updating the point based on the history of error rather than the previous error. The extended adaptiveness significantly improved NSAF in terms of convergence, complexity and noise robustness. The algorithm is also proved for its stability though the step-size is varied. The characteristics of the step-size are also investigated to determine its significance and nature on minimizing the error. The superiority of the MVS-SNSAF algorithm is proved against conventional algorithm using the aforesaid analysis.
Authors:Ayesha Sohail; Farid Chighoub; ZhiWu Li Abstract: Publication date: Available online 2 November 2017 Source:Alexandria Engineering Journal Author(s): Ayesha Sohail, Farid Chighoub, ZhiWu Li A numerical solution of the stochastic fractional order Korteweg-de Vries equation arising in oceanography and plasma physics is approximated using a novel spectral/finite difference tool. The special case for additive time-dependent noise is discussed by taking into account both the uniform and the Gaussian random inputs. A spectral technique for space and a multi-step finite difference scheme for time are employed. Emphasis is made on the spatial spectral discretization error in conjunction with the stochastic approximation error, on the stability bounds and on the amplitude of the stochastic perturbation.
Authors:T.R. Vijaya Lakshmi Abstract: Publication date: Available online 31 October 2017 Source:Alexandria Engineering Journal Author(s): T.R. Vijaya Lakshmi The historical writings were found on stones, palm leaves, cloth, etc. This paper deals with the identification of Telugu Palm leaf characters by acquiring a additional 3D feature on palm leaves. The background of these manuscripts is identical to the writings on them. Removing background from such scripts is a tedious task. This is achieved with the 3D feature depth in the current work. With the help of this 3D feature, an improved classification rate is also achieved.
Authors:Nakone Bello; Alhaji Jibril Alkali; Abubakar Roko Abstract: Publication date: Available online 31 October 2017 Source:Alexandria Engineering Journal Author(s): Nakone Bello, Alhaji Jibril Alkali, Abubakar Roko Recently Kilicman et al. (2006) propose a variational fixed point iteration technique with the Galerkin method for the determination of the starting function for the solution of second order linear ordinary differential equation with two-point boundary value problem without proving the convergence of the method. In this paper, a fixed point iteration method similar to Mann iteration process is proposed and successfully applied to the solution of two-point boundary value problems. We use an affine function satisfying the boundary conditions as a starting approximate solution. We also show the convergence of the method and design a Maple program for the numerical computations. Examples are given to demonstrate the agreement of the results of the proposed method with that of exact solution and existing methods.
Authors:Ahmed S. Negm; Osama A. Hassan; Ahmed H. Kandil Abstract: Publication date: Available online 26 October 2017 Source:Alexandria Engineering Journal Author(s): Ahmed S. Negm, Osama A. Hassan, Ahmed H. Kandil In the era of digital microscopic imaging, Image Processing, data analysis, classification, decision support systems have emerged as one of the most important tools for diagnostic research. Physicians can observe cellular internal structures abnormalities by visualizing and analyzing images. Leukemia is a malignant disease characterized by the uncontrolled accumulation of abnormal white blood cells. The recognition of acute leukemia blast cells in colored microscopic images is a challenging task. The first important step in the automatic recognition of this disease, image segmentation, is considered to be the most critical step. In this study, we present a decision support system that includes the panel selection, segmentation using K-means clustering to identify the leukemia cells and features extraction, and image refinement. After the decision support system successfully identifies the cells and its internal structure, the cells are classified according to their morphological features of this analysis the decision support system was tested using a public dataset designed to test segmentation techniques for identifying specific cells, and the results of this analysis were compared with those of other techniques, which were suggested by other researchers, applied to the same data. The algorithm was then applied to another dataset, extracted under the supervision by an expert pathologist, from a local hospital; the total dataset consisted of 757 images gathered from two datasets. The images of the datasets are labeled with three different labels, which represents three types of leukemia cells: blast, myelocyte, and segmented cells. The process of labeling of these images was revised by the expert pathologist. The algorithm testing using this dataset demonstrated an overall accuracy of 99.517%, the sensitivity of 99.348%, and specificity of 99.529%. Therefore, this algorithm yielded promising results and warrants further research.
Authors:M. Salai Mathi Selvi; G. Hariharan; K. Kannan; M.H. Heydari Abstract: Publication date: Available online 23 October 2017 Source:Alexandria Engineering Journal Author(s): M. Salai Mathi Selvi, G. Hariharan, K. Kannan, M.H. Heydari A mathematical model of an immobilized enzyme system with Michaelis-Menten mechanism for an irreversible reaction is discussed. The model is developed on the basis of diffusion equations containing a nonlinear term related to Michaelis-Menten (M-M) kinetics. In this paper, Legendre wavelets operational matrix of derivatives are used to solve the nonlinear reaction-diffusion equations. The concentration profile of substrate is computed for various parameter values. Also the dimensionless concentration of substrate is established for the slab, cylinder and spherical pallets in different cases. An approximate/analytical expression for substrate concentration is obtained as a function of the Thiele modulus and the Michaelis constant. The proposed wavelet solutions are compared with Adomian decomposition method (ADM) and numerical solutions. Satisfactory agreement with ADM and numerical is observed for all Thiele modulus and M-M constants. Power of the proposed methods is confirmed.
Authors:T. Bharath Kumar; O. Chandra Sekhar; M. Ramamoorty Abstract: Publication date: Available online 21 October 2017 Source:Alexandria Engineering Journal Author(s): T. Bharath Kumar, O. Chandra Sekhar, M. Ramamoorty The composite power system reliability analysis is generally based on minimal path or cut enumeration, tracing of power flow paths from which the related reliability indices are calculated. The minimal cut set is a popular method in the reliability analysis for simple and complex configurations. Average availability of power supply at the consumer end is one of the reliability assessment parameter. This paper is concerned about the evaluation of this reliability index. A step by step procedure for a modified minimal cut set method is explained in this paper using IEEE 6 bus, 14 bus and Single area IEEE RTS 96 system. The proposed algorithm is easy to program and can be applicable to any system. The proposed algorithm is validated with the Classical Node Elimination method, Step by Step algorithm using Conditional Probability and Monte Carlo Simulation method. The proposed technique is tested with a practical example taken from Roy Billinton paper (Reliability evaluation in distribution and transmission systems).
Authors:Hagar Alm El-Din; Medhat Elkelawy; Abd Elnaby Kabeel Abstract: Publication date: Available online 12 October 2017 Source:Alexandria Engineering Journal Author(s): Hagar Alm El-Din, Medhat Elkelawy, Abd Elnaby Kabeel In the present analysis, the dissemination of dimethyl ether (DME) asan alternative fuel with the charged air inside the HCCI engine chamber until accomplishing the burning procedure have been numerically expected by utilizing CFD with detailed chemical kinetics mechanism. The physical technique of the ignition and pollution arrangement in the engine barrel with DME fuel is examined with a developed hydrocarbon reaction mechanism at various HCCI engine loads. The mechanism is including 81 chemical species and 362 basic chemical reactions. Along these lines, the used CFD/discipline code predicts the admittance of the fuel spray, ignition, and pollutant development of DME asa biodiesel fuel. The split injection technique has been used to inject the dimethyl ether remotely at the engine admission tube. The in-cylinder flow field enhances farther the engine chamber fuel/air distribution. The outcomes showed that the blend of DME fuel with charged air is exact and efficient to accomplish the in-barrel blend homogeneity. It is anticipated that, under every engine working condition the production of the methyl radical is considered as imperative part in dimethyl ether pyrolysis and oxidation. In the meantime, the formaldehyde sub-component is a huge division of the general dimethyl ether (DME) ignition system.
Authors:A.E. Kabeel; Z.M. Omara; F.A. Essa; A.S. Abdullah; T. Arunkumar; Ravishankar Sathyamurthy Abstract: Publication date: Available online 12 October 2017 Source:Alexandria Engineering Journal Author(s): A.E. Kabeel, Z.M. Omara, F.A. Essa, A.S. Abdullah, T. Arunkumar, Ravishankar Sathyamurthy Effects of utilizing nanomaterial on the solar still productivity investigated experimentally. Cuprous oxides (CuO) chosen asa nanoparticles material. The nanoparticles added to the black paint of the solar still walls to enhance the solar still performance. Experiments conducted with cuprous oxide nanoparticles weight concentrations ranged from 10% to 40%. It is found that adding nanoparticles to paint increase heat transfer rate and saline water temperature. Solar still productivity of the proposed system is higher than that for the conventional still. Results acquired that utilizing CuO nanoparticles boosted the distillate by 16% and 25% as compared to the conventional solar still (CSS) at weight fraction concentration of 10% and 40%, respectively. Payback period of the distillation system for the modified still using CuO nanomaterials is about 96days, at weight fraction 10%, which is considerable as compared by 89days for CSS.
Authors:Engy Farrag Abstract: Publication date: Available online 14 September 2017 Source:Alexandria Engineering Journal Author(s): Engy Farrag Islam is the fastest growing religion in the world. The Muslim population increases as Islam spreads around the world, which leads to an increasing demand for Islamic buildings such as mosques and Islamic centres. Mosques play an important role in Islam and Muslim life. In several countries, in particular, the Western mosques are seen asa newcomer whose building type is both unique and foreign to local people who are unaccustomed to the visual expression of Islam in the West. The mosque is one of the most visual expressions of global Muslim religious identity in non-Muslim context. The significant numbers of countries have a lot of different architecture styles of their Islamic buildings. Each mosque has its own individual touch. The most important factors behind this variation in form and styles can be divided into nature impacts as (local materials and environment), followed by man-made impacts by (Muslim immigrants, colonialism, funding, and laws, culture, and traditions). The study aims to examine each factor and their influences on the architecture of mosques and Islamic centers in non-Muslim context through analysis and a comparison of a number of examples.
Authors:I.L. Animasaun; I. Pop Abstract: Publication date: Available online 14 September 2017 Source:Alexandria Engineering Journal Author(s): I.L. Animasaun, I. Pop Geometrically, the upper pointed surface of an aircraft and bonnet of a car are examples of upper horizontal surfaces of a paraboloid of revolution (uhspr). The motion of these objects strongly depends on the boundary layer that is formed within the immediate space on it. However, each of these surfaces is neither a horizontal/vertical nor cone/wedge and neither a cone nor a wedge. This article presents the motion of 2-dimensional Blasius flow of Carreau fluid on the surface of such object. The case in which the reaction between the Carreau fluid and catalyst at the surface produces significant temperature differences which consequently set up buoyancy-driven flows within the boundary layer is investigated. Single first-order Arrhenius kinetics is adopted to model the reaction on the surface of the catalyst situated on uhspr which initiates the free convection. Suitable similarity variables are applied to non-dimensionalized, parameterized and reduce the governing partial differential equations to a coupled ordinary differential equations (BVP). The BVP is solved numerically using the shooting technique. Temperature distribution in the flow of viscoelastic Carreau fluid is greater than that of a Newtonian fluid. Local heat transfer rate decreases faster when the Carreau fluid is characterized as shear-thinning. Maximum concentration is guaranteed at a small value of power-law index n and large value of thickness parameter.
Authors:M. El-Adawy; M.R. Heikal; A. Rashid A. Aziz; M.I. Siddiqui; Hasanain A. Abdul Wahhab Abstract: Publication date: Available online 12 September 2017 Source:Alexandria Engineering Journal Author(s): M. El-Adawy, M.R. Heikal, A. Rashid A. Aziz, M.I. Siddiqui, Hasanain A. Abdul Wahhab In-cylinder air flow structures are known to strongly impact on the performance and combustion of internal combustion engines (ICE). Therefore the aim of this paper is to experimentally study an IC engine in-cylinder flow under steady-state conditions. Different methods can be used to characterize the in-cylinder flow which are optical engines and laser diagnostics, computational fluid dynamic and steady-state flow bench. Here we are concentrating on two different types of flow benches. The first (Ricardo) uses the impulse torque meter method while the other (FEV) uses the paddle wheel technique. The experiments were carried out on the same cylinder head and the same pressure difference across the inlet valves of 600mmH2O in order to compare the results. The experimental results are presented in terms of the measured air flow rate, flow coefficient, discharge coefficient and non-dimensional rig tumble. Moreover, number of modifications were conducted on the FEV flow bench in order to apply particle image velocimetry measurements on the vertical tumble plane, which passing through the middle of the cylinder at different valve lifts. The results show that a reasonably good level of agreement can be achieved between both methods, providing the methods of calculations of the various parameters are consistent.
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