Faculty Of Engineering Research Paper

Permanent URI for this collectionhttp://185.252.233.37:4000/handle/123456789/306

Browse

Now showing 1 - 20 of 940

Dipoles formulation for the method of fundamental solutions applied to potential problems
(Copyright © 2006 Elsevier Ltd. All rights reserved., 01/01/2007) S.A.Fam, George,; F.Rashedb2, Youssef,
This paper generalizes and extends the traditional source formulation within the method of fundamental solutions (MFS) to use dipoles (or even series of multi-poles). In this paper, two-dimensional potential problems are considered. The present formulation is formulated by taking the limiting case of two adjacent sources. The necessary kernels are derived in explicit forms. Some numerical examples, covering different cases of boundary conditions and geometry, are solved. Several parametric studies are presented to demonstrate different configurations for placement of sources (monopoles or dipoles). The accuracy of the presented new formulation is verified by comparing its results to those obtained from other numerical and analytical methods. The main advantage of the present formulation lies in decreasing the oscillation in the sources intensity and reducing the number of sources required which is useful especially in concave and narrow geometries.
On the Vibrational Analysis for the Motion of a Rotating Cylinder
(Springer, 01/01/2022) Bek, M. A; Amer, Tarek; Abohamer, Mohamed
The main purpose of this work is to study the motion of 2-DOF of an auto-parametric dynamical system attached with a damped system. The governing equations of motion are gained utilizing Lagrange’s equations in terms of the generalized coordinates. The method of multiple scales (MS) is used to obtain the solutions of the governing equations up to the third order of approximation. The primary external resonance simultaneously with the internal one are investigated to establish the solvability conditions and the modulation equations. The graphical representations of the time histories together with the amplitude and phases of the dynamical system are represented in some plots to describe the motion of the system at any instance. The stability of the solution has been made with use of Mathematica.
Dual-band all textile antenna with AMC for heartbeat monitor and pacemaker control applications
(Cambridge University press, 01/12/2021) Kareem, Farah R; El Atrash, Mohamed; Ibrahim, Ahmed A; Abdalla, Mahmoud A
Currently reading: Abstract Get access Share Cite Rights & Permissions [Opens in a new window] Abstract All textile integrated dual-band monopole antenna with an artificial magnetic conductor (AMC) is proposed. The proposed design operates at 2.4 and 5.8 GHz for wearable medical applications to monitor the heartbeat. A flexible and low-profile E- shaped CPW dual-band textile antenna is integrated with a 4 × 4 dual-band textile AMC reflector to enhance the gain and specific absorption rate (SAR). The SAR is reduced by nearly 95% at both 1 and 10 g. The design was measured on the body with a 2 mm separation. The simulated and measured results appear in high agreement in the case of with and without AMC array integration. The measurement was performed in the indoor environment and in an anechoic chamber to validate the design based on reflection coefficient and radiation pattern measurements.
A Design Chart to Determine the Sizing of Vertical Windows for Daylighting
(Springer, 02/12/2020) Shawky Saifelnasr, Shady
The main objective of this paper is to introduce a simple quick tool for architects represented by a design chart that determines the sizing of vertical windows for providing minimum or average amount of daylight as a function of the properties of the window, the room, and the surrounding environment. One of the most important purposes for introducing windows to a building envelope is providing adequate daylight suitable for the different uses within the different functional spaces. And daylighting might be one of the main reasons for the sizing of those windows. Different calculation methods could be used for daylight calculation and analysis; formula methods, graphical methods, scale models, and computer programs. Although formula methods are not the most accurate daylighting calculation method, they could be used as a rule of thumb especially within the preliminary stages of design. The proposed design charts are derived from formula methods to be used by architects as a simple quick tool that could be used for both design and analysis. They could be used within the design process by finding the sizing of vertical windows. Moreover, they could be used in the analysis of an existing case by finding the available daylight factor. The design charts are a combination of more than one graph to include most of the specifications of the window, the room, and the surrounding environment, to find the sizing of vertical windows, that would ensure the minimum or average amount of daylight for any city all over the world, within the low, middle, or high latitudes.
Proposed structural system for mixed hollow flat slab
(Taylor and Francis, 03/02/2022) Hashad, Ahmed; Helal, Emad
ABSTRACT The economic design of the slabs is the most influential on the construction cost and choosing the appropriate system is the key to the slabs optimal design, and there are many systems that have been developed recently to reach the most economical design. In this research, we try to mix two systems, each of them has its optimal use, and each of them has its advantages and limits for uses, and they have been mixed to try to find a dual system with more advantages. This paper presents a slab system consisting of flat slab system that its field strip areas were replaced with two-way hollow block systems. Consequently, the total weight of the resulting slab was reduced, which positively affected the quantities of steel reinforcement used directly, in addition to its reflection on the design of columns and foundations due to the low self-weight of the slabs. The validity of the proposed concept has been verified through a finite element analysis using Program SAP2000 that was applied to several cases with different configurations under static and dynamic loadings.
Effect of mist cooling technique on exergy and energy analysis of steam injected gas turbine cycle
(PERGAMON-ELSEVIER SCIENCE LTD, 04/05/2016) Abdala, Antar M. M.; Elwekeel, Fifi N. M
The common cogeneration application is steam injected gas turbine. By using cogeneration, it can be obtained with the greatest benefit from fuel energy. In steam injected gas turbine the heat of exhaust gases is used to produce the steam, and this steam injects to combustion chamber. In the present work, the generated steam not only will be directed to the combustion chamber but also will be used to cool the blade turbine by using a closed loop. In this study, the effect of addition mist to steam as coolant fluid was investigated. The energy and exergy analyses for steam injected gas turbine cycle with a closed loop cooling technique by using steam and steam/mist were investigated. The investigation was made at varied values of steam coolant temperature, mist fraction, mist temperature, pressure ratio, turbine inlet temperature and blade temperature. These parameters affected network, plant efficiency, energy ratio, fuel conversion ratio and exergy efficiency. The results show that the efficiency can reach 47.2% at low coolant temperature with a mist fraction of 2%. The coolant heat gain is enhanced at lower mist temperature, so the blade surface temperature can be improved with mist addition to steam. At a mist fraction of 2% exergy efficiency is decreased by 0.03% than that for exergy efficiency of steam only. (C) 2015 Elsevier Ltd. All rights reserved.
Direct Mori-Tanaka calculations of strains in ellipsoidal inclusions with multiple orientations – Comments on the papers: Naili, G. et al. Comp Sci Tech, 187: 107942, 2020 (https://doi.org/10.1016/j.compscitech.2019.107942) and Jain, A. et al., Comp Sci Tech, 87: 86–93, 2013
(ELSEVIER LTD, 04/12/2020) Lomov, S.V; Van Paepegem, W; Abdin, Y; Jain, A
Recently, Naili et al. [1] compared the predictions of strains in inclusions by two methods viz. FE-MT and FE-Voigt for RVE containing 2D ellipsoidal inclusions. In this schemes, multiphase composite (composite having fibers with varying orientations) are homogenized by first homogenizing “pseudo-grains” consisting of fibers having same orientation and aspect ratio using full field Finite Element (FE) simulations. The second step of the homogenization was subsequently performed using the Mori-Tanaka (MT) formulation (the method designated as “FE-MT” homogenization) and the Voigt approximations (“FE-Voigt”). FE homogenization was chosen as the first step of homogenization to ensure that the comparison is “unbiased”. It is known that for uni-directional composites, the MT formulation and FE yield identical results for effective stiffness as well as the strains in the inclusions. Thus, the first step of homogenization could have been MT formulation with no or little change in the results. Further, Naili et al. show that MT-MT is equivalent to the full analytic MT formulation while MT-Voigt is equivalent to the pseudo-grain discretized formulation of the Mori Tanaka homogenization [2].
Constancy of Speed of Light in Inertial Frames
(Natural Sciences Publishing, 05/01/2020) Radi, Hafez A.; Ward, Thomas E.
This article proves that speed of light in all uniformly moving inertial reference frames is absolute as postulated by Einstein. This is first done by considering light propagating with a speed c in all directions in an inertial frame of reference. If that frame is moving uniformly with a speed ν relative to a second stationary inertial frame, we assume that light in the second frame is propagating in all directions with a different speed cρ=ρ c. Consequently, modified transformation Equations are formed. The established Poincaré ellipsoidal light waves are then used to find the Equation that governs the relation of ρ at any speed ν. The analytical solution and numerical calculations to this equation yield a value ρ =1. This proves that speed of light propagates through empty space with speed c independent of the speed of the light source or the observer
Enclosurotopias: A Heterotopian Simulation of Reality
(A+U, 05/08/2020) Abdel-Ghani, Taher; Tahoon, Zeinab
Michel Foucault identifies heterotopias as forms of space that exists somewhere between reality and utopia. It’s real but does not serve or correspond to reality. What appears to be real within heterotopias is the notion of signs, a parallel hyperreal world that encompasses the definition of reality to an extent that it has become the actual meaning of being. Gated communities have long been categorized as the places where fragments of utopia and simulation coexist, and where the illusion of safety flourishes in its most vivid forms. This paper attempts to highlight such heterotopian features within gated communities, with an analytical focus on the Fuyunxindu community in the Tiexi district of Shenyang – a highly controlled residential zone that gave rise to the insider/outsider dichotomy. Through this outlook, the reader gets to answer a simple question: What kind of spatial vision do gated communities provide within the urban realm? Keywords: Gated Communities; Heterotopias; Chinese Urbanism; Neoliberalism; Contemporary Urbanization.
Investigation of Using ANN and Stereovision in Delta Robot for Pick and Place Applications
(IIETA, 05/10/2021) Youssef, Abdelrahman; Bayoumy, Amgad M; Atia, Mostafa R.A
Although the Delta robot has many applications in pick-and-place operations, some problems limit its use. The difficult programming is one of these limitations. Parallel robot programming depends on solving the forward and inverse kinematics equations of the robot. These equations relate the geometric parameters, such as length and angle of every robot arm, to the position of the end effector and vice versa. The kinematic equations are hard to be derived. Moreover, any change in the robot geometry, due to a change in the application condition, requires that new kinematic equations be derived. This needs a very sophisticated and specialized programmer, who is not always available. Consequently, this problem limits the use of parallel robots. This paper discusses the use of ANN and embedded systems in addition to stereo vision to command delta robot in pick-and-place operations. The method is implemented and tested giving satisfactory results.
Concept and analysis of a coupled split-ring resonator for wide-/dual bands, self-filtering, high out-of-band suppression and highly efficient antennas
(Cambridge University Press, 05/12/2020) Abdalla, Mahmoud A.; El Atrash, Mohamed; El-Sobky, Nour A.; Zahran, Sherif R.
An inspired metamaterial-based highly efficient monopole antenna displaying wide-/dual-band resonances along with self-filtering properties is presented. The monopole has high out-of-band suppression characteristics that lead to very close to 0 dB band-stop between the antenna dual resonant bands. The antenna operates at the two WLAN services of 2.65-3.25 and 5-7 GHz with stopband with total reflection at 4.5 GHz. The designed filtering characteristics are based on current coupling for the dual-band functions and current neutralization for the stopband function. Moreover, the proposed antenna has a very high radiation efficiency of 97 and 99% at 3 and 6 GHz, respectively. Furthermore, the proposed antenna exhibits an omni-directional radiation pattern with coplanar waveguide feed for simple integration with passive/active devices. Moreover, the antenna properties are achieved with a compact antenna size (30 × 30 mm2). With all presented results, the proposed antenna is very competitive over recent relevant antennas. In addition, a very good agreement between theoretical, full-wave simulations and measurements is achieved. © 2020 Cambridge University Press and the European Microwave Association
Process optimization in Poultry Feed Mill
(Springer, 06/02/2022) Amin, Sameh; Sobhi, Nahed
Poultry feed industry is a pretty much active in a lot of countries and it is achieved market acceptance. The final products are supposed to meet certain specifications to fulfill the nutritional need for animals at different life periods. The final product for poultry is shipped in the form of pelleted feed for the convenience of consumption. This paper focuses on improving production rates while maintaining quality specifications of the final products in an Egyptian poultry feed factory. The improvement approach is conducted by observing the main operating parameters of productivity; statistical analysis is conducted to observe the effect of those parameters on the production rate and the quality of the product. Comparison between parameters levels is done through analysis of variance to determine the significance of the tested parameters. The optimization of parameters was applied with Minitab and designed expert software to determine the best operating conditions. The obtained results showed that the downtime decreases by 16% monthly and the productivity increased by 35% and the pellet durability index increased by 0.8% after applying these parameters with total saving 2,160,000 LE.
Constructing a conceptual tool of sociable public places: An integrated approach
(Cairo University, 06/03/2020) Shehata, L.M; Gabr, H.S; Alsadaty, A.H
This paper presents an attempt to construct a conceptual tool for urban designers, architects, and landscape architects to use for developing an analytical guideline model for redevelopment of sociable public open spaces in contemporary cities. The construction of the conceptual tool is developed based on the integration between the continuum place-shaping process and the qualities of sociability in public open spaces as a direct outcome of such process; an issue that has been omitted by most post-occupancy review of urban design projects. Consequently, the theoretical knowledge of this paper is constructed based on readings and pertinent research studies of place-shaping process, place sociability and place phenomenon that are relevant to the research problem. The theoretical foundation of thoughts and concepts are combined to create a conceptual tool to understand place-shaping of sociable public places as a real assemblage. This conceptual tool is put forward as a positive step for establishing analytical guideline models for redevelopment of sociable public spaces. This tool can also be used as a comprehensive evaluation method based on the integration between place-shaping process and places that are in a changeable emergence state over time
A study of the relationship between contemporary memorial landscape and user perception
(Ain Shams University, 06/03/2021) Attwa, Yousra; Refaat, Mohammed; Kandil, Yasmin
Contemporary Memorial landscape (CML) integrated within the city and people's life is rapidly growing. It is a landscaped space commemorating individuals or events of the past and keeping them in the memory of people, through physical representation in public areas, by being active rather than passive spaces. Users experience these memorials through engagement with different perceptions, as a result of senses experienced at that space. Placing CML in everyday life and allowing users to engage strengthen their memory and place attachment. This research carries an analysis of CML classification, urban physical configuration, and user sensual experience. The research is carried through literature review and analytical studies for three examples; 9/11, Diana's, and Jewish memorial. This research highlights the difference between monuments, memorials, and CML. The research concludes a theoretical framework, based on user's interpretation highlighting their sensual perception, helping the designers bridge their ideas to the user, leading to memorial success. © 2021 THE AUTHORS
Wearable high gain low SAR antenna loaded with backed all-textile EBG for WBAN applications
(Institution of Engineering and Technology, 07/01/2020) Mohamed, Ibrahim S.; El Atrash, Mohamed; Abdalgalil, Omar; Mohamed, Ibrahim; Abdalla, Mahmoud Abdelrahman; Zahran, Sherif. R.
View references (37) A high gain, low specific absorption rate, oval-shaped monopole antenna is presented. It is backed by an all-textile 3 × 3 array of electromagnetic bandgap (EBG) unit cells. The antenna is printed on the thin Rogers ULTRALAM 3850 substrate, while the EBG array is composed of the conductive ShieledIT Super and dielectric substrate felt. The design operates at 2.45 GHz of the Industrial, Scientific, and Medical band. Due to the close distance between the extended grounds of the co-planar waveguide feeding configuration and the oval-shaped monopole antenna, current-coupling was achieved, leading to gain enhancement. However, with body-loading cases, resonance at 2.45 GHz was attained at a separation of 30 mm. By incorporating the EBG array, as an isolator, this issue was resolved. In free space and over a gap of 3 mm from the human body, gain enhancements by 2.68 and 11.54 dB were achieved at 2.45 GHz, respectively. Simulated and measured results are benchmarked. Furthermore, SAR simulation study showed reductions by 99.5%, averaged over 1 and 10 g of tissue. © The Institution of Engineering and Technology 2020
Efficient Resource Allocation Scheme in Multi-User LiFi Networks Based on Angle Oriented Transceiver
(Institute of Electrical and Electronics Engineers Inc., 07/01/2021) Selmy, Hossam A. I; Elsayed, Hany M
In this paper, an efficient resource allocation scheme in multi-user LiFi networks is proposed using the angle oriented (AO) technology at the receiver and transmitter sides. To cope with the inter-symbol and inter-user interferences and to further enhance the fairness between the users, we efficiently allocate the resources by choosing the most suitable LED for each AO transmitter (i.e., user) to be ON. The none-selected LEDs are switched OFF to maximize the received signal-to-interference-plus-noise-ratios (SINRs). The resource allocation problem under consideration is a discrete non-convex one with multi-objective optimizations. To obtain the optimal solution, the exhaustive-search (ES) method is used while to reduce the complexity, a suboptimal method is proposed using genetic algorithm (GA) scheme. Our results confirm the accuracy of the proposed sub-optimal solution where less than 0.5 dB difference in the SINR value is noticed. Also, the proposed LiFi system with AO technology shows a superior performance compared to the conventional systems with single transmitter (ST) scheme. © 2021 IFIP TC6 WG6.10.
Enhancement of device characteristics of CNT-TFET: Role of electrostatic doping and work function engineering
(Ain Shams University, 07/06/2022) Ossaimee, Mahmoud; Salah, Ahmed; Gamal, Salah H; Shaker, Ahmed; Salem, M.S
In this work, an Electrostatic Doped Carbon Nanotube Tunneling FET (ED CNT-TFET) has been designed and simulated using a work function engineering technique. An intrinsic CNT is introduced as a channel material and a doped pocket is created between the source and the channel by utilizing an appropriate work function to boost the ON-state current of the device. Moreover, dielectric pocket engineering is applied to boost the high-frequency performance. The simulations, performed in this work, are conducted through a 2D solution of Poisson and Schrodinger equations which are done by utilizing the unbalanced Green function formalism. Simulation results demonstrate that the proposed device structure could improve the ON-current, cut-off frequency, and achieve a low subthreshold swing (SS) value which makes it suitable for low power applications. Additionally, the presented structure could also eliminate ambipolar conduction.
Gate Dielectric Constant Engineering for Alleviating Ambipolar Conduction in MOS-GNRFET
(The electrochemical journal, 07/09/2021) Mahmoud, MennaTullah; Salem, Marwa. S; Ossaimee, M
In the current study, a gate dielectric constant engineering approach is reported to minimize the ambipolar conduction in MOSFET-Like Graphene Nano Ribbon (MOS-GNRFET). The dielectric constants, k, over different regions of the device play a crucial role in energy band diagram modification. So, by choosing suitable values of k over the drain, channel and source regions, the band-to-band tunneling (BTB) path at the drain–channel interface can be minimized. Subsequently, the ambipolar current in MOS-GNRFET is decreased substantially. In addition, the high frequency performance is investigated considering the cutoff frequency, fT, as a figure of merit. It has been found that the proposed technique reduces the ambipolar current by about four orders, decreases OFF-current by two orders and consequently increases ON/OFF current ratio by two orders giving a value of 2.9 × 1010. It has been found that the proposed technique does not deteriorate the gate capacitance which, in turn, enhances fT that reaches about 23 THz, making the proposed structure efficient for digital and analog performance.
Numerical analysis and design of high performance HTL-free antimony sulfide solar cells by SCAPS-1D
(Elsevier, 07/12/2021) Salem, Marwa S; Shaker, Ahmed; Othman, Mohamed S; Al-Bagawia, Amal H; Fedawy, Mostafa; Aleid, Ghada Mohamed
Among the various absorbers encountered in thin film solar cells (TFSCs), antimony sulfide (Sb2S3) is considered a suitable candidate as it is a non-toxic and earth-abundant besides its high absorption coefficient. However, some critical issues cause its poor photovoltaic performance. These include unoptimized Sb2S3 layer, interface recombination and cell properties like the ineffective carrier collection and transport. To enhance the power conversion efficiency (PCE) of Sb2S3 solar cell, we suggest some design guidelines by employing device simulation. First, a calibration step is performed vs an experimental arrangement consists of FTO/TiO2/Sb2S3/Spiro-OMeTAD/Au to validate the simulation model. Next, as the organic hole transport material (HTM) often has poor long-term operation stability and demands high-cost fabrication processes, an HTL-free cell is proposed and designed by investigating the impact of the main technological and physical parameters. In the first step in the design of the HTL-free cell, we provide an affinity engineering methodology to tune the conduction band offset between the electron transport layer (ETL) and the absorber. Based on this approach, the most appropriate electron transport material (ETM) is chosen that fulfills the maximum efficiency. Then, an optimization routine is performed to select the most appropriate design parameters and the PCE of the optimized case is found to be about 22%. All simulations, carried out in this work, are performed by SCAPS-1D device simulator under AM1.5G illumination and 300 K temperature.
Analysis of Hybrid Hetero-Homo Junction Lead-Free Perovskite Solar Cells by SCAPS Simulator
(MDPI, 09/12/2021) Salem, Marwa. S; Shaker, Ahmed; Zekry, Abdelhalim; Abouelatta, Mohamed; Alanazi, Adwan; Alshammari, Mohammad T; Gontand, Christian
In this work, we report on the effect of substituting the active intrinsic i-layer on a conventional pin structure of lead-free perovskite solar cell (PSC) by a homo p-n junction, keeping the thickness of the active layer constant. It is expected that when the active i-layer is substituted by a p-n homo junction, one can increase the collection efficiency of the photo-generated electrons and holes due to the built-in electric field of the homo junction. The impact of the technological and physical device parameters on the performance parameters of the solar cell have been worked out. It was found that p-side thickness must be wider than the n-side, while its acceptor concentration should be slightly lower than the donor concentration of the n-side to achieve maximum efficiency. In addition, different absorber types, namely, i-absorber, n-absorber and p-absorber, are compared to the proposed pn-absorber, showing a performance-boosting effect when using the latter. Moreover, the proposed structure is made without a hole transport layer (HTL) to avoid the organic issues of the HTL materials. The back metal work function, bulk trap density and ETL material are optimized for best performance of the HTL-free structure, giving Jsc = 26.48, Voc = 0.948 V, FF = 77.20 and PCE = 19.37% for AM1.5 solar spectra. Such results highlight the prospective of the proposed structure and emphasize the importance of using HTL-free solar cells without deteriorating the efficiency. The solar cell is investigated by using SCAPS simulator.

Browse

Browsing Faculty Of Engineering Research Paper by Issue Date