Arab Academy for Science, Technology & Maritime Transport
Recent publications
This paper presents the modeling and control process of recently developed manipulator with 3 limbs having prismatic-universal-universal (3-PUU) joints. It has 3 degrees of freedom (3-DOF), consisting of 2 rotational DOFs and 1 translational DOF (2R1T). To avoid the computational complexity of solving the manipulator’s kinematics in real-time application, two artificial neural networks (ANNs) are trained to estimate the forward and inverse kinematics solutions. Training and testing results show that the developed ANNs have great prediction capabilities. The manipulator’s dynamic model is deduced using MATLAB Simscape environment. Control schemes are investigated starting with motor control, first using PID controller, and then adding feed-forward control which greatly improved the motors’ response. Closed-loop trajectory control based on Cartesian space feedback of the manipulators’ position and orientation and inverse kinematics ANN is then studied. The closed-loop control scheme can enhance the system’s performance, eliminating the error resulting from any change in the manipulator’s actual model due to manufacturing or assembly defects. Simulation results of a defected manipulator model show that the closed-loop control scheme improved the manipulator’s trajectory tracking capability, reducing the z-axis position error by 89.23% and the orientation error by 86.76% and 82.83% about x-axis and y-axis directions respectively.
A novel 120 Gbps free space optics (FSO) transmission scheme is introduced by combining orbital angular momentum (OAM) multiplexed signals with spectral amplitude coded (SAC)-optical code division multiplexing access (OCDMA) technique. Four OAM beams, each carrying three independent channels with 10 Gbps data rate, are used for increasing the capacity of the FSO system to 120 Gbps. Enhanced double weight (EDW) codes are employed for the SAC-OCDMA system. The proposed system is simulated and its performance is compared for the twelve channels under different weather conditions including clear air (CA), varying levels of rain, haze and fog conditions. The obtained results reveal that longer propagation distances between transmitter and receiver are possible with a bit error rate (BER) of ∼ 10⁻⁵. The possible distances are, respectively, 300 m, 160 m, 200 m, and 150 m, under CA, heavy rain (HR), heavy haze (HH), and heavy fog (HF), with a system capacity of 120 Gbps.
Savonius turbine is a vertical axis wind turbine (VAWT) which is suitable to operate at low wind velocities. The experimental investigation to improve its performance is a big challenge as; it is expensive, complicating and time consuming. Numerical prediction using CFD simulation could be a valuable alternative. This paper introduces a new modification of Savonius wind rotors to improve its performance. The proposed modification consists of a curtain arrangement together with fin addition on blade. The effect of the proposed modification was predicted using a CFD simulation employing ‘ANSYS FLUENT 16′. The curtain arrangement was located in front of the rotor to avoid the opposing torque to the rotor rotation. The fins were added to exploit the space in the blade for guiding the wind flow. The performance of the rotor with different curtain arrangements and variable number of fins was predicted and assessed against that of the conventional rotor. This comparison aimed to optimize the geometrical data of the proposed curtain arrangement with the number of added fins. The maximum power coefficient of the Savonius wind rotor was found to be increased to about 42 % with the optimum curtain arrangement (lengths of the curtain blades 1000 and 1150 mm and the angles of the curtain blades 30 and 50) together with adding only one fin. The simulation results showed that the performance of Savonius wind rotors could be significantly enhanced with a proper selection of curtain arrangement and number of fins to be added on the blade.
The (2 + 1) dimensional Konopelchenko–Dubrovsky equation (2D-KDE) is an integro differential equation which describes two-layer fluid in shallow water near ocean shores and stratified atmosphere. In this respect, the solutions of (2D-KDE) describe two dual functions which represent two-layer fluid. Here, we are concerned with deriving self-similar (similarity) solutions of the inhomogeneous-nonautonomous (2D-KDE). In this context, the model equations are nonlinear partial differential equations (NLPEs) with space and time dependent coefficients. It is worth noticing to mention that, the (2D-KDE) with space and time dependent coefficients was not considered in the literature up to date. So that, the present work is novel. In fact, only the study of (NLPDEs) with space dependent or time dependent coefficients was carried. This was done by using Lie symmetry. Here, we use a different technique together with introducing similarity transformations. The similarity solution are obtained via the extended unified method (EUM), which is an alternative technique to the use of Lie group symmetries of (NLPDEs). It is worthy to mention that the (EUM) is of low cost time in symbolic computations and it provides a wide class of solutions. The solutions presented here, are classified to hyperbolic and elliptic functions.The results are obtained via symbolic computations and they are evaluated numerically and displayed in graphs. Multiple solutions structures are observed. Among them dromian pattern, bridge shape, lumps vector and interaction between longitudinal and lateral complex waves. These results are completely new. A unified approach for analyzing the stability of the steady state solution is established. The stability of the is determined against varying the relevant parameters. It is found that stability holds against the dispersion coefficient, while instability holds against the nonlinearity coefficient and the phase velocity.
Lithium-ion (Li-ion) batteries are the workhorse of energy storage systems in electric vehicles (EVs) due to their high energy density and desirable characteristics. To obtain an optimized and safe operation, a battery management system (BMS) should be implemented to provide the main safety features based on the estimation of different battery states, which entails an accurate, fast, and adaptive mathematical model. In this paper, a data-driven linear model using dynamic mode decomposition is proposed. The proposed modeling procedure bridges the gap between abstracted models (e.g., circuit-based models) and empirical models (e.g., data-driven models) of Li-ion batteries. Unlike the abstracted models, the proposed model does not impose any assumptions on what the model should be, and also considers the battery as a black box similar to the empirical techniques, and yet gives an interpretable linear model in state space form. In order to generate this model, only one discharge cycle that contains high dynamic content is required, and no other specialized tests are required. Two models are proposed for the Li-ion battery, namely, a model-based estimator based on Kalman filter for BMS purposes and a piecewise model for offline simulation. The results are verified experimentally via a lab scale prototype.
Prediction of wireless channel scenarios is fundamental for modern wireless communication systems with diverse propagation conditions. Moreover, the type of data extracted from a wireless communication channel impulse response (CIR) is complex. In recent research, machine learning (ML) techniques have proven their success in classification problems of wireless communication scenarios and provide reasonable results. In this paper, a new enhanced feature selection method is proposed to improve the training model and classification performance of the conventional model. This improvement is achieved based on the concept of regularization in which the selection of the best features is considered before training the model under any propagation environment. The adoption of regularization leads to a high Total Explained Variance (TEV) during the process of kernel Principal Component Analysis (k-PCA). As a consequence, two principal features are used instead of three. The proposed model has high generalization ability since it reduces the features dimensionality (computational complexity) and, generally, enhances the ML classification performance. Experimental simulation is executed to compare the proposed model and the conventional one in terms of accuracy, precision and recall. The accuracy is increased from 97% to 99%, from 96% to 99%, from 89% to 97% and from 90% to 98% for k-nearest neighbor (k-NN), support vector machine (SVM), k-Means and Gaussian mixture model (GMM), respectively.
The construction industry is one of the most important in today’s world, having a significant impact on any country’s economy and society. As per a current worldwide prediction, it will be a key contributor to worldwide economic expansion in this decade until 2030, with output expected to be 35% greater than in the past 10 years to 2020. Making a significant contribution to societal needs by improving people’s quality of life. Otherwise, and based on volume, this industry accounts for 35 % of global Dioxide (Co2) emissions, approximately 30 % of greenhouse gas emissions, and generating 45 % to 65 % of waste disposed of in landfills. With global environmental awareness growing, the construction industry is starting to take action to decrease its environmental impact. Suitable construction and demolition waste management can provide significant benefits in aspects of sustainability and life quality, as well as significant benefits to the global construction industry. Diesel is the utility player in the construction industry, powering more than three-fourths of all heavy-duty trucks and being the major source of greenhouse emissions, so a suitable alternative had to be found. Biodiesel as a suitable alternative fuel has interesting properties such as renewability, non-toxicity, biodegradability, and environmental friendliness. The cost of feedstocks is one of the vital challenges with biodiesel production. Recycling construction and demolition waste to produce biodiesel as a raw material or as a co-solvent to improve biodiesel quality and operation conditions, such as carbon dioxide and calcium oxide, would save a significant number of resources, lowering operation and production costs. The focus of this paper is to manage the construction and demolition waste and find the suitable exploitation of it, by technical comparison between crude tall oil and waste cooking oil with Co2 as a co-solvent has been applied and simulated in ASPEN HYSYS® V9. The use of non-catalytic transesterification to generate biodiesel from crude tall oil and waste cooking oil with Co2 from construction and demolition waste has been recognized as an efficient technique. It has a few benefits over traditional catalytic transesterification, including the elimination of catalyst preparation and separation of negative issues. HYSYS® was used to generate detailed operating specifications and unit design details for each process. These processes were applied to a technological assessment to define their technical benefits and drawbacks. The findings indicate that the crude tall oil supercritical process recommended, as it is the lowest in terms of the number of equipment used by 30% and the more economical in the amount of using raw materials by 80% in a quarter of the reaction time compared by waste cooking oil with Co2 process under somewhat similar operating conditions. However, all processes were proven to be able to produce a high-quality biodiesel product that matched EN14214 biodiesel standards and requirements.
Adopting unsustainable farming strategies and practices in Egypt led to several socio-economic and environmental problems that are strongly reflected in human health and lifestyle. An example of these problems in the livestock sector is insufficient meat production leading to the dependence on imported meat or cattle. This is in addition to the pollution caused by the unprocessed and wasted cattle manure. To develop the livestock sector in Egypt researchers must introduce new energy solutions to farmers and smallholders. This paper aims to economically compare Photovoltaic (PV) to Anaerobic Digestion (AD) projects’ benefits within the livestock sector in Egypt, considering their Life Cycle Costs (LCC) and other parameters using systems components available in the local market. The study proves that the electricity load is the main reason for using either PV or AD. A real case study of a livestock farm is considered to determine its energy profile. Later on, an optimization procedure is implemented for hybrid PV/AD power supplies to optimize the Cost of Energy (CoE) and guarantee a continuous power supply depending on the best use of land and cattle number covered within the comparison. The results show that the CoE produced from renewables is still higher than the CoE from the grid. Furthermore, the rated tariff set by the government to buy electricity from investors will never attract farmers and smallholders to invest in renewables in case of consistent grid power. In other words, farmers under these conditions would only invest in renewables in case a power outage threatens their businesses.
Underwater flowlines (pipelines and cables) have become a popular option worldwide as communication lines. Correspondingly the demand for underwater trenching increased with the most desirable method internationally, jet trenching for its benefits in protecting the flowlines from external hazards. However, the trenching method is suffering from a main problem that can affect the construction and operation phases. This problem is the use of maximum jetting pressure needed for underwater trenching which leads to extra costs in the construction phase. Furthermore, the unstraightening of the trench can cause extra stress on the flowline requiring extra maintenance in the operation phase. The key cause of this problem is the classification of the underwater soil, as if the underwater soils cannot be classified as accurately as possible, the suitable jetting pressure required to trench these soils could not be applied correctly. Therefore, this research aims to develop a machine learning classifier for soil classification as a solution for enhancing the performance of the underwater trenching process. This classifier was constructed, trained, and evaluated by MATLAB R2020a to classify the underwater soil type by analyzing the soil image samples by an artificial neural network (ANN). Then a prototype that mimics exactly the real trenching mechanism was built to test the developed classifier based on three different types of soil (sand, clay & gravel). The results showed that the classifier successfully identify and classify the three different types of soil used. Finally, the results confirmed that the classifier will enhance the trenching processes. As it eliminates the need for soil classification by conventional methods while executing it in an easy fast process that will save energy, and cost, and decrease the need for future maintenance processes.
Saving energy is as important as energy production. In systems like cars, trains, elevators, and machines that require frequent start/stop operation, a significant amount of kinetic energy is wasted during braking. It may be necessary to employ a sophisticated breaking mechanism to catch waste kinetic energy for later usage. Several criteria influence the proposed braking mechanism. A hydraulic test bench is developed and built to investigate how much kinetic energy can be absorbed and stored during braking using a hydraulic circuit. The test bench’s driving power is a variable voltage and variable frequency electric motor that drives a flywheel that constitutes the majority of the kinetic energy with speeds ranging from 876 to 2975 rpm. A positive displacement gear pump, flow control valve, non-return valve, on/off valve, direction control valve, and an accumulator are the major components of the hydraulic circuit. The use of an automated contactor and a magnetic clutch allows for alternate operations between the mechanical system and the hydraulic brake circuit. The entire system is theoretically modeled, and a MATLAB code is created to investigate the impact of various parameters on the braking mechanism’s performance. Four groups of experiments were conducted to investigate the features of the driving and braking systems, as well as the influence of various factors on the amount of energy that may be collected during braking. The results indicate that 18% to 55% of the kinetic energy may be absorbed and transformed into hydraulic power stored in the accumulator. The amount of hydraulic power gained is governed by the operating speed and restriction ratio (hydraulic system resistance). At certain rotational speeds and restriction ratios, maximum gain hydraulic power could well be produced. Not only can braking energy regeneration improve system efficiency, but it also provides environmental benefits. Alexandria, Egypt is used as a case study to investigate the economic and environmental benefits of employing this technology in cars.
As a result of the copious interest and development in multifunctional electronics, the need for a multifunctional platform with a stable and unique performance has become one of the most important research concerns. In this embodiment, the amorphous Ge2Sb2Te5 (a-GST) thermally evaporated phase-change thin films are utilized for photo/thermodetection applications. The structural, compositional, and topographical methodologies confirm the amorphous nature with smooth surface topology and average particle size of about 31 ± 10 nm. Furthermore, the optical properties of the deposited a-GST revealed the broadband absorption spectrum with indirect energy gap and Urbach energy of about 0.54 eV and 380 meV, respectively. Furthermore, the dispersion and electronic parameters of the deposited films are determined. The switchable resistivity properties of Au/a-GST/Au are evaluated, and the phase change transition is observed in the temperature range (413–463) K. Moreover, the microelectronic parameters and interface features, in addition to the charge carriers' dynamics in the fabricated Ag/a-GTS/n-Si/Au–Sb heterojunction, are interpreted and analyzed in detail. Besides, the thermodetection capability of the fabricated heterojunction is evaluated in the temperature range (303–573) K. The estimated values of the thermosensitivity of about – (28.02 ± 1) and – (3.60 ± 0.13) mV/K at driving activation current of 600 μA for the two phases regions, respectively. Additionally, the photodetection performance of the implemented architecture is tested under halogen illumination of intensity (20–100) mW/cm². The fabricated device shows a remarkably stable light signal response with responsivity, specific detectivity, and trise/tfall of about 203.1 mA/W, 2.84 × 10⁹Jones, and 267 ms/84 ms, respectively. Ultimately, based on the recorded results, the Au/a-GST/n-Si/Au–Sb heterojunction is suggested for multifunctional applications with promising performance.
Multiphase winding configurations have gained significant attention in high-performance variable speed drives and wind energy conversion systems (WECS) owing to their myriad advantages. In the available literature, various multiphase winding layouts have been designed aiming at boosting the machine performance to meet the requirements of the proposed applications. Ultimately, this paper surveyed the state-of-the-art in the available multiphase winding layouts proposed for various innovative applications. Various types of windings were discussed, while investigating their advantages and limitations. This typically considers the winding layouts employed in multiphase induction motors (IMs) and permanent magnet (PM) machines with prime phase and multiple three-phase orders. This study extensively provides innovative winding arrangements that offer better machine characteristics in terms of torque density, efficiency, and fault-tolerance capability. Moreover, the construction of multiphase machines with general n -phase using standard three-phase stator frames has been elaborated. This latter technique obviates the basic necessity of special stator frames with a prime number of phases. Finally, this paper sheds light on the commercial applications that include multiphase winding layouts.
A new series of vinyl amide-, imidazolone-, and triazinone-linked combretastatin A-4 analogues have been designed and synthesised. These compounds have been evaluated for their cytotoxic activity against MDA-MB-231 breast cancer cells. The triazinone-linked combretastatin analogues (6 and 12) exhibited the most potent cytotoxic activity, in sub-micromolar concentration compared with combretastatin A-4 as a reference standard. The results of β-tubulin polymerisation inhibition assay appear to correlate well with the ability to inhibit β-tubulin polymerisation. Additionally, these compounds were subjected to biological assays relating to cell cycle aspects and apoptosis induction. In addition, the most potent compound 6 was loaded on PEG-PCL modified diamond nanoparticles (PEG-PCL-NDs) and F4 was picked as the optimum formula. F4 exhibited enhanced solubility and release over the drug suspension. In the comparative cytotoxic activity, PEG-PCL modified F4 was capable of diminishing the IC50 by around 2.89 times for nude F4, while by 3.48 times relative to non-formulated compound 6.
Novel closed-form solutions of the dynamic vibration equations of seismically excited structures are derived by using the Laplace transform. Structures with single-degree-of-freedom (SDOF) and multi-degree-of-freedom (MDOF) are considered and modelled as lumped mass systems. Several earthquake records with different peak ground accelerations (PGAs) are used to excite such systems. To be compared, time-history responses are obtained numerically by using Newmark's step-by-step iteration method and analytically by the proposed approach. After conducting such comparisons, the proposed approach successfully computes the exact responses of seismically excited structures. ARTICLE HISTORY
This work introduces a novel model that describes the elastic-mechanical-thermodiffusion waves of semiconductor material. The holes and electrons interaction is considered when the material is exposed to laser pulses. The thermal conductivity can be chosen as a function of temperature. The photothermal (PT) effect during the thermoelasticity theory is obtained according to the temperature gradient. The one-dimensional (1D) deformation (thermoelastic and electronic) is used to explain the main governing equations. The dimensionless fields and initial conditions are introduced during the PT transport processes. The main physical fields are obtained algebraically using the Laplace transform. The solution mechanism of the problem depends on boundary conditions which are taken at the free surface. The boundary conditions are formulated according to the mechanical ramp type. To obtain the solutions of the fields in the real space–time domain, the inversion of the Laplace transform according to the Riemann-sum approximation method is used. According to the numerical results and the graphical representations, some comparisons are made under the impact of laser pulses and variable thermal conductivity as well as the variation of thermal memories.
Propagation of nonlinear waves in the magnetized quantum Thomas–Fermi dense plasma is analyzed. The Zakharov–Kuznetsov–Burgers equation is derived by using the theory of reductive perturbation. The exact solution contains both solitary and shock terms. Also, it is shown that rarefactive waves propagate in most cases. Both the associated electric field and the wave energy have been derived. The effects of dust and electrons temperature, dust density, magnetic field magnitude, and direction besides the effect of the kinematic viscosity on the amplitude, width, and energy of the formed waves are discussed. It is shown that the negative energy wave is formed and its value is enhanced due to the increase of the kinematic viscosity and the ambient magnetic field which lead to an increase in the instability. The present results are helpful in controlling the stabilization of confined Thomas–Fermi dense magnetoplasma that are found in white dwarfs and in the high-intensity laser-solid matter interaction experiments.
Within visual culture, postcyberpunk films are best approached as places of Otherness whereby human identity and agency are downplayed and posthumans are magnified in highly technopolic societies marked with scientific determinism. Postcyberpunk treats the posthuman enclave as a heterotopic site, oscillating between utopian and dystopian spaces, potentially and optimistically, creating a space for humanity to be reassessed and renegotiated. Against this backdrop, the current research endeavor proposes a Spatio-Cognitive Model of Posthuman Representation focusing attention on heterotopic ‘spaces’ and ‘bodies’ in hyperconnected environments. While the model owes a substantial debt to Foucault’s writings on heterotopia and the utopian body, in tilting the focus of enquiry, this paper is informed by the tenets of polyrhythmia, hypermimesis, spatial repertoires, semiotic assemblages and cognitive embodiment as insightful interventions. Blade Runner 2049 is taken as a fertile case study grounded in paradoxes and ambiguities around the contradiction between humans and replicants, artificial intelligence and super-large enterprises. The hybridity pertinent to the postcyberpunk film genre and the inner and outer topographies of posthuman representation proved to be insightful investigative vantage points of multimodal inquiry for the socio-political and technocratic implications they underlie. With technology seamlessly integrated into social spaces and posthuman bodies, Blade Runner 2049 is arguably structured as an emotional journey composed of multiple heterotopias (spatial layers, ruptures and bifurcations expressed through socio-political capitalist projections). The article adamantly argues for new philosophical perspectives and praxis in redefinition of the social relationship between human and posthuman.
A new hybrid polarization division multiplexing (PDM) spectral amplitude coding optical code division multiple access (SAC-OCDMA) is proposed for free space optical (FSO) for capacity enhancement. Two polarization signals are utilized; one is x-polarization and carries three different channels at 0° azimuthal angle while the other is y-polarization at 90° azimuthal angle, and carries the same three channels. Each channel is assigned with a diagonal permutation shift (DPS) code and carries 10 Gbps. The suggested system is simulated, and its performance is evaluated in terms of maximum allowable number of users, propagation range, bit error rate (BER), Q-factor, and received power for the different channels under various fog, dust storm, and rain scenarios. The reported results indicate that the system can support a signal travelling up to 2, 0.9, and 1.3 km, respectively, under light fog (LF), light dust (LD), and light rain (LR). As the level of these weather conditions is increased from light to moderate, the FSO link length decreases to 1.3, 0.25, and 1.8 km under medium fog (MF), medium dust (MD), and medium rain (MR), respectively. Furthermore, the shortest propagation range is achieved as the level of weather conditions becomes heavy, where the FSO link range becomes 1, 0.095, and 1.1 km under heavy fog (HF), heavy dust (HD), and heavy rain (HR), respectively. All these ranges are considered at BER ≤ 10–3 and a received power ≤ − 27 dBm with 60 Gbps overall data transmission. This new hybrid FSO system is suggested to be implemented in desert areas that affects by dust storms and in 5G wireless transmission communications.
Locally available apricot ( Prunus armeniaca L.) seed shell wastes were utilized for the preparation of an efficient dye biosorbent. The as-prepared apricot seed shell powder ( ASP ) was thoroughly characterized using FTIR, SEM-EDX, XRD, BET surface area, and pH PZC measurements to elucidate its functional groups, as well as its surface texture morphology and charge. The effect of several process variables (such as contact time, biosorbent dosage, pH, temperature, and initial concentration) on the dye uptake capacity was also investigated. Based on the experimental finding, the following optimum process conditions were established in the study: pH 2.0, 0.2 g/L adsorbent mass, 30 °C, and time of 120 min. The BET surface area, pore volume, and average pore size of the ASP were estimated as 97.493 m ² /g, 0.0691 cm ³ /g, and 1.922 nm, respectively. The experimental equilibrium and kinetic data were properly described by the Temkin isotherm and pseudo-first-order kinetics model, respectively. Therefore, the effectiveness of ASP as an acid blue 193 dye biosorbent was established in the study.
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3,455 members
mohamed b Abdelhalim
  • College of Computing and Information Technology
Magdy M. Saeb
  • Former Head of Department of Computer Engineering
Mohamed Mostafa Fouad
  • College of Management and Technology
Ali Shahata
  • Department of Mechanical Engineering
Walid Abdelmoez
  • College of Computing and Information Technology
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Prof. Ismail Abd El-Ghafaar
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