Search results for: Abdelrahman Mahmoud Abdelgwad

Authors: Dina Mohamed Ahmed Mahmoud Bakr

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The concept of a circular economy is gaining increasing attention as a way to promote sustainable economic growth and reduce the environmental impact of human activities. The circular economy is a systemic approach that aims to keep materials and resources in use for as long as possible, minimize waste and pollution, and regenerate natural systems. The purpose of this article is to present a summary of the principles and tactics employed in the circular economy, along with examples of prosperous circular economy projects implemented in different sectors across Japan, Austria, the Netherlands, South Africa, Germany, and the United States. The paper concludes with a discussion of the challenges and opportunities associated with the transition to a circular economy and the policy interventions that can support this transition.

Keywords: circular economy, waste reduction, sustainable development, recycling

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Authors: Rana Mahmoud

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This study represents a systematic study of the Operational Transconductance Amplifiers capacitance (OTA-C) filters or as it is often called Gm-C filters. OTA-C filters have been paid a great attention for the last decades. As Gm-C filters operate in an open loop topology, this makes them flexible to perform in low and high frequencies. As such, Gm-C filters can be used in various wireless communication applications. Another property of Gm-C filters is its electronic tunability, thus different filter frequency characteristics can be obtained without changing the inductance and resistance values. This can be achieved by an OTA (Operational Transconductance Amplifier) and a capacitor. By tuning the OTA transconductance, the cut-off frequency will be tuned and different frequency responses are achieved. Different high-order analog filters can be design using Gm-C filters including low pass, high pass and band pass filters. 1st and 2nd order low pass, high pass and band pass filters are presented in this paper.

Keywords: Gm-C, filters, low-pass, high-pass, band-pass

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Authors: Abdelrahman Taha, Niloofar Malekghaini, Hamed Ebrahimian, Ramin Motamed

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This paper compares the substructure and direct methods for soil-structure interaction (SSI) analysis in the time domain. In the substructure SSI method, the soil domain is replaced by a set of springs and dashpots, also referred to as the impedance function, derived through the study of the behavior of a massless rigid foundation. The impedance function is inherently frequency dependent, i.e., it varies as a function of the frequency content of the structural response. To use the frequency-dependent impedance function for time-domain SSI analysis, the impedance function is approximated at the fundamental frequency of the structure-soil system. To explore the potential limitations of the substructure modeling process, a two-dimensional reinforced concrete frame structure is modeled using substructure and direct methods in this study. The results show discrepancies between the simulated responses of the substructure and the direct approaches. To isolate the effects of higher modal responses, the same study is repeated using a harmonic input motion, in which a similar discrepancy is still observed between the substructure and direct approaches. It is concluded that the main source of discrepancy between the substructure and direct SSI approaches is likely attributed to the way the impedance functions are calculated, i.e., assuming a massless rigid foundation without considering the presence of the superstructure. Hence, a refined impedance function, considering the presence of the superstructure, shall be developed. This refined impedance function is expected to significantly improve the simulation accuracy of the substructure approach for structural systems whose behavior is dominated by the fundamental mode response.

Keywords: direct approach, impedance function, soil-structure interaction, substructure approach

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Authors: Rayan Elsiddig Eltaib, Yamanaka Norikazu, Mubarak Abdelrahman Abdalla

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This study investigated the effects of Acacia Senegal, Calotropis procera, Leptadenia pyrotechnica, Ziziphus spina Christi, Balanites aegyptiaca, Indigofera oblongigolia, Arachis hypogea and Sesimum indicum grown in the western region of White Nile State on soil properties of the 0-10, 10-30, 30-60 and 60-90 cm depths. Soil properties were: pH(paste), electrical conductivity of the saturation extract (ECe), total N (TN), organic carbon (OC), soluble K, available P, aggregate stability and water holding capacity. Triplicate Soil samples were collected after the end of the rainy season using 5 cm diameter auger. Results indicated that pH, ECe and TN were not significantly different among plant cover types. In the top 10-30 cm depth, OC under all types was significantly higher than the control (4.1 to 7.7 fold). The highest (0.085%) OC was found under the Z. spina Christi and A. Senegal whereas the lowest (0.045%) was reported under the A. hypogea. In the 10-30 cm depth, with the exception of A. hypogea, Z. spina christi and S. indicum, P content was almost similar but significantly higher than the control by 72 to 129%. In the 10-30 cm depth, K content under the S. indicum (0.46 meq/L) was exceptionally high followed by Z. spina christi (0.102 meq/L) as compared to the control (0.029 meq/L). Water holding capacity and aggregate stability of the top 0-10 cm depth were not significantly different among plant cover types. Based on the fact that accumulation of organic matter in the soil profile of any ecosystem is an important indicator of soil quality, results of this study may conclude that (1) cultivation of A.senegal, B.aegyptiaca and Z. spina Christi improved soil quality whereas (2) cultivation of A. hypogea or soil that is solely invaded with C. procera and L.pyrotechnica may induce soil degradation.

Keywords: canopy, crops, shrubs, soil properties, trees

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Authors: Mohamed Mahmoud

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This paper has developed an effect-cause analysis technique for fault diagnosis in digital circuits. The main algorithm of our technique is based on the Enhanced Deduction Algorithm, which processes the real response of the CUT to the applied test T to deduce the values of the internal lines. An experimental version of the algorithm has been implemented in C++. The code takes about 7592 lines. The internal values are determined based on the logic values under the permanent stuck-fault model. Using a backtracking strategy guarantees that the actual values are covered by at least one solution, or no solution is found.

Keywords: enhanced deduction algorithm, backtracking strategy, automatic test equipment, verfication

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Authors: Mohammad Mahmoud Mandurah

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The existence of InfoMiracles in scripture is evidence that the scripture has a divine origin. It is also evidence to the existence of God. An InfoMiracle is an information-based miracle. The basic component of an InfoMiracle is a piece of information that could not be obtained by a human except through a divine channel. The existence of a sufficient number of convincing InfoMiracles in a scripture necessitates the existence of the divine source to these InfoMiracles. A mathematical equation is developed to prove that the Qur’an has a divine origin, and hence, prove the existence of God. The equation depends on a single variable only, which is the number of InfoMiracles in the Qur’an. The Qur’an is rich with InfoMiracles. It is shown that the existence of less than 30 InfoMiracles in the Qur’an is sufficient proof to the existence of God and that the Qur’an is a revelation from God.

Keywords: InfoMiracle, God, mathematical proof, miracle, probability

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Authors: M. S. Mahmoud

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In this paper, the adsorption performance of a novel environmental friendly material, calcium alginate gel beads as a non-conventional technique for the successful removal of copper ions from aqueous solution are reported on. Batch equilibrium studies were carried out to evaluate the adsorption capacity and process parameters such as pH, adsorbent dosages, initial metal ion concentrations, stirring rates and contact times. It was observed that the optimum pH for maximum copper ions adsorption was at pH 5.0. For all contact times, an increase in copper ions concentration resulted in decrease in the percent of copper ions removal. Langmuir and Freundlich's isothermal models were used to describe the experimental adsorption. Adsorbent was characterization using Fourier transform-infrared (FT-IR) spectroscopy and Transmission electron microscopy (TEM).

Keywords: adsorption, alginate polymer, isothermal models, equilibrium

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Authors: Ahmed Elsebaay, Maged A. Abu Adma, Mahmoud Ramadan

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This study presents a technique clarifying the effect of ambient air temperature and loads power factor changing from standard values on electric generator power rating. The study introduces an optimized technique for selecting the correct electric generator power rating for certain application and operating site ambient temperature. The de-rating factors due to the previous effects will be calculated to be applied on a generator to select its power rating accurately to avoid unsafe operation and save its lifetime. The information in this paper provides a simple, accurate, and general method for synchronous generator selection and eliminates common errors.

Keywords: ambient temperature, de-rating factor, electric generator, power factor

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Authors: Mahmoud M. Othman, Y. G. Hegazy, A. Y. Abdelaziz

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This paper proposes a novel heuristic algorithm that aims to determine the best size and location of distributed generators in unbalanced distribution networks. The proposed heuristic algorithm can deal with the planning cases where power loss is to be optimized without violating the system practical constraints. The distributed generation units in the proposed algorithm is modeled as voltage controlled node with the flexibility to be converted to constant power factor node in case of reactive power limit violation. The proposed algorithm is implemented in MATLAB and tested on the IEEE 37 -node feeder. The results obtained show the effectiveness of the proposed algorithm.

Keywords: distributed generation, heuristic approach, optimization, planning

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Authors: Aya Mousa, Mahmoud Alsaheb

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Question Answering System (QAS) aims to provide the most suitable answer to the user's question in any natural language. In the recent future, it will be a future version of web search. Much research has already been done on answering Arabic factoid questions and achieved good accuracy. In contrast, the progress in research on Arabic non-factoid question answering is still immature. In this survey, we summarize, discuss, and compare the existing Arab non-factoid question-answering systems to identify the limitations and the achievements that were accomplished. Furthermore, we investigate the challenges in developing non-factoid Arabic QAS and the possible future improvements. The survey is written to help the researchers to understand the field of Arabic non-factoid QAS and to motivate them to utilize different approaches to develop and enhance the Non-factoid Arabic QAS

Keywords: Arabic question answering system, non-factoid question answering, Arabic NLP, question answering

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Authors: Fadila Mohamed Mahmoud., Derkaoui I., Krimi Z.

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Date palm is a plant which presents a very good adaptation to the difficult conditions of the environment in particular to the drought and saline stress even at high temperatures. This adaptation is related on the biology of the plant and to the presence of a microflora endophyte which live inside its tissues. Fifteen endophytics fungi isolated from date palm were tested in vitro in the presence of various NaCl concentrations to select halotolerantes isolates. These same endophytes were tested for their colonizing capacity by the description of the production of secondary metabolites more particularly the enzymes (pectinases, proteases, and phosphorylases), and the production of antibiotics and growth hormones. Significant difference was observed between the isolates with respect to the tests carried out.

Keywords: Date palm, Halotolerantes, endophyte, Secondary metabolites.

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Authors: Mohammad Asadpour, Maryam Sadeghi, Mahmoud Jafari

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The transformation of carbon dioxide into fuels and commodity chemicals is considered one of the most attractive methods to meet energy demands and reduce atmospheric CO₂ levels. Cobalt complexes have previously shown high faradaic efficiency in the reduction of CO₂ to CO. In this study, a nanostructure, referred to as a porphyrin-like buckyball, is simulated and analyzed for its electrical properties. The investigation aims to understand the unique characteristics of this material and its potential applications in electronic devices. Through computational simulations and analysis, the electrocatalytic reduction of CO₂ to CO by Cobalt-porphyrin-like buckyball is explored. The findings of this study offer valuable insights into the electrocatalytic properties of this predicted structure, paving the way for further research and development in the field of nanotechnology.

Keywords: porphyrin-like buckyball, DFT, nanomaterials, CO₂ to CO

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Authors: Mohamed Moustafa Mahmoud Sedky

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In line start permanent magnet synchronous motor, eccentricity is a common fault that can make it necessary to remove the motor from the production line. However, because the motor may be inaccessible, diagnosing the fault is not easy. This paper presents an FEM that identifies different models, static eccentricity, dynamic eccentricity, and mixed eccentricity, at no load and full load. The method overcomes the difficulty of applying FEMs to transient behavior. It simulates motor speed, torque and flux density distribution along the air gap for SE, DE, and ME. This paper represents the various effects of different eccentricities types on the transient performance.

Keywords: line start permanent magnet, synchronous machine, static eccentricity, dynamic eccentricity, mixed eccentricity

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Authors: Abdelrahman Elsehsah

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The main objective of this study is to assess changes in the water capacity of Aswan High Dam Lake (AHDL) caused by evaporation and seepage losses. To achieve this objective, a comprehensive methodology was employed. The methodology involves acquiring Sentinel-3 imagery and extracting the surface area of the lake using remote sensing techniques. Using water areas calculated from sentinel images, collected field data, and the lake’s water balance equation, monthly evaporation and seepage losses were estimated for the years 2021 and 2022. Based on the water balance method results, the average monthly evaporation losses for the year 2021 were estimated to be around 1.41 billion cubic meters (Bm3), which closely matches the estimates provided by the Ministry of Water Resources and Irrigation (MWRI) annual reports (approximately 1.37 Bm3 in the same year). This means that the water balance method slightly overestimated the monthly evaporation losses by about 2.92%. Similarly, the average monthly seepage losses for the year 2022 were estimated to be around 0.005 Bm3, while the MWRI reports indicated approximately 0.0046 Bm3. By another means, the water balance method overestimated the monthly seepage losses by about 8.70%. Furthermore, the study found that the average monthly evaporation rate within AHDL was 210.88 mm/month, which closely aligns with the computed value of approximately 204.9 mm/month by AHDA. These findings indicated that the applied water balance method, utilizing remote sensing and field data, is a reliable tool for estimating monthly evaporation and seepage losses as well as monthly evaporation rates in AHDL.

Keywords: Aswan high dam lake, remote sensing, water balance equation, seepage loss, evaporation loss

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Authors: Mustapha Mahmoud, Fouzia Toumi Benali, Mohamed Benyahia, Sofiane Bouazza

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This work focuses on the influences of biological and chemical parameters on the phenolic compounds such as flavonoids and tannins in different medicinal plants in western Algeria (Papaver rhoeas, Daphnegnidium, Lavandula multifida, Lavandula dentata, Lavandula stoicha, ...). Thus we look the difference between species of the same genus, difference between the different organs of the same species, the influence of environment all temperature influences, time, percentage of solvent on the extraction. Quantification of the phenolic compounds was performed by spectrophotometric method then treated with statistics tools such as variance analysis, multivariant analyzes, response surface methodology). The results show that the polyphenols are influenced by the parameters mentioned.

Keywords: polyphenols, influences, medicinal plants, west Algeria

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Authors: Ahmed M. Khedr, Saad M. Abdelrahman, Kareem M. Tonbol

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Two geo-referenced sea level datasets (September 2008 – November 2010) and (April 2012 – January 2014) were recorded at Alexandria Western Harbour (AWH). Accurate re-definition of tidal datum, referred to the latest International Terrestrial Reference Frame (ITRF-2014), was discussed and updated to improve our understanding of the old predefined tidal datum at Alexandria. Tidal and non-tidal components of sea level were separated with the use of Delft-3D hydrodynamic model-tide suit (Delft-3D, 2015). Tidal characteristics at AWH were investigated and harmonic analysis showed the most significant 34 constituents with their amplitudes and phases. Tide was identified as semi-diurnal pattern as indicated by a “Form Factor” of 0.24 and 0.25, respectively. Principle tidal datums related to major tidal phenomena were recalculated referred to a meaningful geodetic height datum. The portion of residual energy (surge) out of the total sea level energy was computed for each dataset and found 77% and 72%, respectively. Power spectral density (PSD) showed accurate resolvability in high band (1–6) cycle/days for the nominated independent constituents, except some neighbouring constituents, which are too close in frequency. Wind and atmospheric pressure data, during the recorded sea level time, were analysed and cross-correlated with the surge signals. Moderate association between surge and wind and atmospheric pressure data were obtained. In addition, long-term sea level rise trend at AWH was computed and showed good agreement with earlier estimated rates.

Keywords: Alexandria, Delft-3D, Egypt, geodetic reference, harmonic analysis, sea level

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Authors: Mahmoud Salari

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Corruption and gender inequality are the main topics of interest for both economists and policymakers. This study develops various static and dynamic estimation models to examine the impact of gender inequality in politics and the labor market on corruption using data of 170 countries from 1998 to 2014. This study uses two most reliable corruption indexes, including Corruption Perceptions Index (CPI) and Corruption Control (CC), to evaluate corruption levels across countries. The results indicate that gender inequality in politics has a strong impact on corruption level, and those countries that have larger/smaller gender inequality in their parliaments are faced with higher/lower corruption, respectively. Meanwhile, there is no enough evidence that supports the relationship between gender inequality in the labor market and corruption, and the results indicate that gender inequality in the labor market is not directly linked to the corruption level.

Keywords: corruption, female labor force participation, politics, gender inequality

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Authors: Saeed Kamarian, Mahmoud Shakeri

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Sandwich structures are used in a variety of engineering applications including aircraft, construction and transportation where strong, stiff and light structures are required. In this paper, frequency maximization of Functionally Graded Sandwich (FGS) beams resting on Pasternak foundations is investigated. A generalized power-law distribution with four parameters is considered for material distribution through the thicknesses of face layers. Since the search space is large, the optimization processes becomes so complicated and too much time consuming. Thus a novel meta–heuristic called Imperialist Competitive Algorithm (ICA) which is a socio-politically motivated global search strategy is implemented to improve the speed of optimization process. Results show the success of applying ICA for engineering problems especially for design optimization of FGM sandwich beams.

Keywords: sandwich beam, functionally graded materials, optimization, imperialist competitive algorithm

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Authors: Mahmoud I. Syam

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Stratified double median ranked set sampling (SDMRSS) method is suggested for estimating the population mean. The SDMRSS is compared with the simple random sampling (SRS), stratified simple random sampling (SSRS), and stratified ranked set sampling (SRSS). It is shown that SDMRSS estimator is an unbiased of the population mean and more efficient than SRS, SSRS, and SRSS. Also, by SDMRSS, we can increase the efficiency of mean estimator for specific value of the sample size. SDMRSS is applied on real life examples, and the results of the example agreed the theoretical results.

Keywords: efficiency, double ranked set sampling, median ranked set sampling, ranked set sampling, stratified

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Authors: Mahmoud Samkan

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Dispersed Generation (DG) is a promising solution to many power system problems such as voltage regulation and power loss. This paper proposes a heuristic two-step method to optimize the location and size of DG for reducing active power losses and, therefore, improve the voltage profile in radial distribution networks. In addition to a DG placed at the system load gravity center, this method consists in assigning a DG to each lateral of the network. After having determined the central DG placement, the location and size of each lateral DG are predetermined in the first step. The results are then refined in the second step. This method is tested for 33-bus system for 100% DG penetration. The results obtained are compared with those of other methods found in the literature.

Keywords: optimal location, optimal size, dispersed generation (DG), radial distribution networks, reducing losses

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Authors: Ghada Hasabo, Mahmoud Saber Elbasiouny, Mervat Abdelsalam, Sherin Ghaleb, Niveen Eldessouky

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In the near future, nanotechnology is envisaged for large scale use. Hence health and safety issues of nanoparticles should be promptly addressed. In the present study the acute hepatoxicity assessment due to high single oral dose of nano iron and micro iron particles were studied. The normal daily activities, biochemical alterations, blood coagulation, histopathological changes in Wister rats were the aspect of the toxicological assessment.This work found that significant alterations in biochemical enzymes (serum iron level, liver enzymes, albumin, and bilirubin levels), blood coagulation (PT, PC, INR), and histopathological changes occurred more prominently in the nano iron particle treated group.

Keywords: nanobiotechnology, nanosystems, nanomaterials, nanotechnology

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Authors: Adel M. Mahmoud

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This Investigation was conducted to determine the productivity and water use efficiency for new sunflower genotypes. Ten sunflower genotypes were evaluated under drip irrigation using two treatments of. Results indicate that decreasing the amount of irrigation water from 1500 to 1130 mm/hectar significantly reduced all studied traits. Mutation (M1-63) surpassed all the other one genotypes in seed yield and WUE. Lines which gave the highest yield of the seed have water use efficiency under drought conditions higher than water use efficiency under normal irrigation. The lowest depression in seed yield due to drought conditions has been registered for Line 20, Line M1-63 and Sakha 53 genotypes (11 , 18 and 16 %, respectively). Genotypes (Line 20 , Line M1-63 and Sakha 53) are more tolerant to drought than others and we can used its in breeding program to develop sunflower hybrids suitable for cultivation under drought condition.

Keywords: sunflower genotypes, water use efficiency, mutation, inbred lines

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Authors: Mohaddeseh Ahmadnezhad, Shahrbano Oryan, Mahmoud Bahmani, Mohammadd Sayad Bourani

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Changes in abundance and size of skin ionocytes were investigated in two larval stage of Caspian sea zander, Sander lucioperca, before and after yolk sac absorption, at 96h after transfer from fresh water (FW; <0.5‰) to 7‰ (estuary) and 12‰ (Caspian sea water=CW) salinity. Survival rate in the stage of after yolk sac absorption were more than larval pre-absorbed yolk sac in condition of salinity (p<0.05). Ionocyte abundance increased significantly in 7 and 12‰ salinity (p<0.05), but not about ionocyte size. The results of this study suggest that development of skin Ionocyte osmoregulatory function and osmoregulation capability of Caspian Sea zander larvae increased with growth of the larvae.

Keywords: Caspian Sea, larvae, Sander lucioperca, salinity, skin ionocyte

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Authors: Mahmoud M. S. Albattah

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Urbanization results in the expansion of administrative boundaries, mainly at the periphery, ultimately leading to changes in landcover. Agricultural land, naturally vegetated land, and other land types are converted into residential areas with a high density of constructs, such as transportation systems and housing. In urban regions of rapid growth and change, urban planners need regular information on up to date ground change. Amman (the capital of Jordan) is growing at unprecedented rates, creating extensive urban landscapes. Planners interact with these changes without having a global view of their impact. The use of aerial photographs and satellite images data combined with topographic information and field survey could provide effective information to develop urban change and growth inventory which could be explored towards producing a very important signature for the built-up area changes.

Keywords: highway design, satellite technologies, remote sensing, GIS, image segmentation, classification

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Authors: Nour S. Abdelrahman, Seunghyun Hong, Hassan A. Arafat, Daniel Choi, Faisal Al Marzooqi

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Abstract—The advancement of lithium extraction methods from water sources, particularly saltwater brine, is gaining prominence in the lithium recovery industry due to its cost-effectiveness. Traditional techniques like recrystallization, chemical precipitation, and solvent extraction for metal recovery from seawater or brine are energy-intensive and exhibit low efficiency. Moreover, the extensive use of organic solvents poses environmental concerns. As a result, there's a growing demand for environmentally friendly lithium recovery methods. Membrane-based separation technology has emerged as a promising alternative, offering high energy efficiency and ease of continuous operation. In our study, we explored the potential of lithium-selective sieve channels constructed from layers of 2D graphene oxide and MXene (transition metal carbides and nitrides), integrated with surface – SO₃₋ groups. The arrangement of these 2D sheets creates interplanar spacing ranging from 0.3 to 0.8 nm, which forms a barrier against multivalent ions while facilitating lithium-ion movement through nano capillaries. The introduction of the sulfonate group provides an effective pathway for Li⁺ ions, with a calculated binding energy of Li⁺ – SO³⁻ at – 0.77 eV, the lowest among monovalent species. These modified membranes demonstrated remarkably rapid transport of Li⁺ ions, efficiently distinguishing them from other monovalent and divalent species. This selectivity is achieved through a combination of size exclusion and varying binding affinities. The graphene oxide channels in these membranes showed exceptional inter-cation selectivity, with a Li⁺/Mg²⁺ selectivity ratio exceeding 104, surpassing commercial membranes. Additionally, these membranes achieved over 94% rejection of MgCl₂.

Keywords: ion permeation, lithium extraction, membrane-based separation, nanotechnology

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Authors: Mahmoud Karimi, Golmohammad Khoobbakht

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This study focuses on the exergy flow analysis in the transesterification of waste cooking oil with methanol to decrease the consumption of materials and energy and promote the use of renewable resources. The exergy analysis performed is based on the thermodynamic performance parameters namely exergy destruction and exergy efficiency to investigate the effects of variable parameters on renewability of transesterification. The experiment variables were methanol to WCO ratio, catalyst concentration and reaction temperature in the transesterification reaction. The optimum condition with yield of 90.2% and exergy efficiency of 95.2% was obtained at methanol to oil molar ratio of 8:1, 1 wt.% of KOH, at 55 °C. In this condition, the total waste exergy was found to be 45.4 MJ for 1 kg biodiesel production. However high yield in the optimal condition resulted high exergy efficiency in the transesterification of WCO with methanol.

Keywords: biodiesel, exergy, thermodynamic analysis, transesterification, waste cooking oil

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Authors: Nidal H. Abu-Zahra, Mahmoud Algazzar

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In this research, n-dodecylthiol was added to P3HT/PC70BM polymer solar cells to improve the crystallinity of P3HT and enhance the phase separation of P3HT/PC70BM. The improved crystallinity of P3HT/PC70BM doped with 0-5% by volume of n-dodecylthiol resulted in improving the power conversion efficiency of polymer solar cells by 33%. In addition, thermal annealing of the P3HT/PC70MB/n-dodecylthiolcompound showed further improvement in crystallinity with n-dodecylthiol concentration up to 2%. The highest power conversion efficiency of 3.21% was achieved with polymer crystallites size L of 11.2nm, after annealing at 150°C for 30 minutes under a vacuum atmosphere. The smaller crystallite size suggests a shorter path of the charge carriers between P3HT backbones, which could be beneficial to getting a higher short circuit current in the devices made with the additive.

Keywords: n-dodecylthiol, congugated PSC, P3HT/PCBM, polymer solar cells

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Authors: M. Mourad, K. Mahmoud

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Recently hybrid vehicles have become a major concern as one alternative vehicles. This type of hybrid vehicle contributes greatly to reducing pollution. Therefore, this work studies the influence of electrification phase of hybrid electric vehicle on emission of vehicle at different road conditions. To accomplish this investigation, a simulation model was used to evaluate the external characteristics of the hybrid electric vehicle according to variant conditions of road resistances. Therefore, this paper reports a methodology to decrease the vehicle emission especially greenhouse gas emission inside cities. The results show the effect of electrification on vehicle performance characteristics. The results show that CO₂ emission of vehicle decreases up to 50.6% according to an urban driving cycle due to applying the electrification strategy for hybrid electric vehicle.

Keywords: electrification strategy, hybrid electric vehicle, driving cycle, CO2 emission

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Authors: Hasan S. Mahmoud, Salwa M. Beheiry, Vian Ahmed

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In light of the repercussions of the 2008 global economic crisis, the response of the United Arab Emirates economy and growth, and the vast construction activities that are undergoing, there is a need to investigate the relationship between construction activities and the Gross Domestic Product (GDP). This study aims to investigate the causality relationship between the construction industry in the United Arab Emirates and the GDP of the country in the last decade. For that, this study will investigate the relationship between the growth of the GDP and the growth of construction activities and their value addition to the economy. To ascertain this relationship, Granger Causality method is used to identify the causality between the time-dependent series.

Keywords: construction value addition, Granger causality, growth of gross domestic product, United Arab Emirates

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Authors: Mahmoud I. Syam, Osama K. El-Hafy

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With lack of student motivation, there will be a little or no real learning in the class and this directly effects student achievement and test scores. Some students are naturally motivated to learn, but many students are not motivated, they do care little about learning and need their instructors to motivate them. Thus, motivating students is part of the instructor’s job. It’s a tough task to motivate students and make them have more attention and enthusiasm. As a part of this research, a questionnaire has been distributed among a sample of 155 students out of 1502 students from Foundation Program at Qatar University. The questionnaire helped us to determine some methods to motivate the students and encourage them to study such as variety of teaching activities, encouraging students to participate during the lectures, creating intense competition between the students, using instructional technology, not using grades as a threat and respecting the students and treating them in a good manner. Accordingly, some hypotheses are tested and some recommendations are presented.

Keywords: learning, motivating, student, teacher, testing hypotheses

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