amr saleh

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Manta Ray Foraging Optimization for the Virtual Inertia Control of Islanded Microgrids Including Renewable Energy Sources

Sustainability

Nowadays, the penetration level of renewable energy sources (RESs) has increased dramatically in ... more Nowadays, the penetration level of renewable energy sources (RESs) has increased dramatically in electrical networks, especially in microgrids. Due to the replacement of conventional synchronous generators by RESs, the inertia of the microgrid is significantly reduced. This has a negative impact on the dynamics and performance of the microgrid in the face of uncertainties, resulting in a weakening of microgrid stability, especially in an islanded operation. Hence, this paper focuses on enhancing the dynamic security of an islanded microgrid using a frequency control concept based on virtual inertia control. The control in the virtual inertia control loop was based on a proportional-integral (PI) controller optimally designed by the Manta Ray Foraging Optimization (MRFO) algorithm. The performance of the MRFO-based PI controller was investigated considering various operating conditions and compared with that of other evolutionary optimization algorithm-based PI controllers. To achiev...

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Encoderless Finite Control Set Predictive Current Control of Synchronous Reluctance Motor

2019 21st International Middle East Power Systems Conference (MEPCON)

In this paper, a simplified robust method for encoderless finite control set predictive current c... more In this paper, a simplified robust method for encoderless finite control set predictive current control (FCSPCC) for synchronous reluctance motor (SRM) is suggested, discussed, and simulated. The predictive current control replaces the conventional PI current controllers used in field oriented control to a strategy that uses a discrete model for SRM which predicts the future values of the currents for all the possible switching vectors for two-level inverter. Furthermore, the cost function is performed to select the optimal switching vector to apply in the next sampling interval. Additionally, PCC establishes a convergence mechanism to follow the reference values of the desired speed. For encoderless control, Extended Kalman filter (EKF) is composed in the rotating reference frame to estimate the position and speed of the rotor and the currents for SRM. Those estimated values are fed back into the predictive model. To demonstrate its feasibility, the presented control is executed through MATLAB/Simulink during different speed area including zero and reversal speed. Simulation results show high robustness and reliability of the drive with low harmonic distortion (THD).

Additional file 3: of Pilot randomized controlled trials in the orthopaedic surgery literature: a systematic review

References of Included Pilot and Definitive RCTs. (DOCX 30 kb)

Additional file 2: of Pilot randomized controlled trials in the orthopaedic surgery literature: a systematic review

Modified Scoring of the CLEAR NPT Scale. (DOCX 87 kb)

Additional file 1: of Pilot randomized controlled trials in the orthopaedic surgery literature: a systematic review

Search Strategy. (DOCX 63 kb)

High-Performance Position Sensorless control of Reluctance Synchronous Motor using High-Frequency Injection

2019 IEEE 13th International Conference on Power Electronics and Drive Systems (PEDS), 2019

This paper presents an enhanced method for a self-sensing (Sensorless) Field Oriented Control (FO... more This paper presents an enhanced method for a self-sensing (Sensorless) Field Oriented Control (FOC) of Reluctance Synchronous Motor (SRM) based on high-frequency signal injection. The rotor saliency characteristic with the difference between the $d$-axis and $q$-axis inductance of the motor is used for position estimation through adding a small high-frequency current signal injected in an arbitrary rotating frame. Modulation technique is applied to the sensed voltages and currents to extract a signal that is proportional to the difference between the actual position and an estimated position. This error signal is used as input to a Phase-Locked Loop (PLL) to get the position and the speed of the machine. Particle Swarm Optimization technique (PSO) is used to tune the parameters of speed, current and PLL controllers. The major objective of this drive is to give a robust and dynamic estimation of the rotor angle and speed independent of the operating condition. The proposed methodology is validated by simulation results to clarify the ability of the proposed technique in different speed area.

Disguised Terrorism Versus Political and Economic Failures- Which Diagnosis Do We Need to Recognize? 205 Countries in Two Decades of Analysis

International Journal of Economics and Finance, 2021

Identifying the causes of terrorism has been a goal of researchers for decades. The evidences and... more Identifying the causes of terrorism has been a goal of researchers for decades. The evidences and implications of terrorism are both extremely ambiguous, but also poignant. Dealing with terrorism has become the centerpiece of political debates for years. Despite of that, it has always been followed by the similar and identical uncompromising and intransigent security measures in different parts of the world, even if the reasons behind the acts combine many and different types of human sides, including political, social, security, psychological, cultural, and religious dimensions. There are lots of tremendous feelings, not only for the victims but also for the assailants that believe in their unprejudiced acts and are continuously able to justify their significance of the use of violence. That is why the paper started by introducing the subject to the reader, including the terms related to the phenomena, but also introducing the idea that there is an economic cost associated with thi...

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Robust Sensorless Direct Speed Predictive Control of Synchronous Reluctance Motor

2020 IEEE 29th International Symposium on Industrial Electronics (ISIE), 2020

To achieve a fast dynamic response, sufficient load response, and good tracking performance, a pr... more To achieve a fast dynamic response, sufficient load response, and good tracking performance, a precision and robust method for sensorless direct speed predictive control (DSPC) of synchronous reluctance motor (SynRM) is proposed and simulated in this paper. The proposed method replaces the cascaded control structure (i.e. speed and currents loops) of the field-oriented control to a strategy that exploits all the electrical and mechanical variables in one control law to select the optimal switching vector for the two-level inverter to apply in the next sampling interval. Furthermore, for robustness, an extended Kalman filter (EKF) is used to observe rotor speed and position, stator currents, and mechanical load torque, and consequently, the system reliability is improved and the cost is decreased. Then, the observed variables are fed back into the prediction model. For simplicity, particle swarm optimization (PSO) is applied to tune the weighting factors of the cost function and EKF covariance matrices. Simulation results reveal the robustness and reliability of the proposed method.

Modal Analysis of a Vertical-Axis Darrieus Wind Turbine Blade with a Troposkein Shape

Topics in Modal Analysis & Testing, Volume 9, 2018

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Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

The Lancet, 2021

Background Congenital anomalies are the fifth leading cause of mortality in children younger than... more Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58•0%) were male. Median gestational age at birth was 38 weeks (IQR 36-39) and median bodyweight at presentation was 2•8 kg (2•3-3•3). Mortality among all patients was 37 (39•8%) of 93 in low-income countries, 583 (20•4%) of 2860 in middle-income countries, and 50 (5•6%) of 896 in high-income countries (p<0•0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90•0%] of ten in lowincome countries, 97 [31•9%] of 304 in middle-income countries, and two [1•4%] of 139 in high-income countries; p≤0•0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2•78 [95% CI 1•88-4•11], p<0•0001; middle-income vs high-income countries, 2•11 [1•59-2•79], p<0•0001), sepsis at presentation (1•20 [1•04-1•40], p=0•016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4-5 vs ASA 1-2, 1•82 [1•40-2•35], p<0•0001; ASA 3 vs ASA 1-2, 1•58, [1•30-1•92], p<0•0001]), surgical safety checklist not used (1•39 [1•02-1•90], p=0•035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1•96, [1•41-2•71], p=0•0001; parenteral nutrition 1•35, [1•05-1•74], p=0•018). Administration of parenteral nutrition (0•61, [0•47-0•79], p=0•0002) and use of a peripherally inserted central catheter (0•65 [0•50-0•86], p=0•0024) or percutaneous central line (0•69 [0•48-1•00], p=0•049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030. Funding Wellcome Trust.

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Advanced Strategy of Speed Predictive Control for Nonlinear Synchronous Reluctance Motors

Machines, 2020

To gain fast dynamic response, high performance, and good tracking capability, several control st... more To gain fast dynamic response, high performance, and good tracking capability, several control strategies have been applied to synchronous reluctance motors (SynRMs). In this paper, a nonlinear advanced strategy of speed predictive control (SPC) based on the finite control set model predictive control (FCS-MPC) is proposed and simulated for nonlinear SynRMs. The SPC overcomes the limitation of the cascaded control structure of the common vector control by employing a novel strategy that considers all the electrical and mechanical variables in one control law through a new cost function to obtain the switching signals for the power converter. The SynRM flux maps are known based on finite element method (FEM) analysis to take into consideration the effect of the nonlinearity of the machine. To clear the proposed strategy features, a functional and qualitative comparison between the proposed SPC, field-oriented control (FOC) with an anti-windup scheme, and current predictive control (C...

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The Impact of Covid-19 Spread on Stock Markets: The Case of the GCC Countries

International Business Research, 2020

This paper attempts to investigate the effects of 2020 Covid-19 world-wide spread on stock market... more This paper attempts to investigate the effects of 2020 Covid-19 world-wide spread on stock markets of GCC countries. Coronavirus spread has been measured by cumulative cases, new cases, cumulative deaths and new deaths. Coronavirus spread has been measured by numbers per million of population, while stock market return is measured by Δ in stock market index. Papers conducted in this topic tend to analyze Coronavirus spread in the highly infected countries and focus on the developed stock markets. Countries with low level of infection that have emerging financial markets seem to be less attractive to scholars concerning with Coronavirus spread on stock markets. This is why we try to investigate the GCC stock markets reaction to Covid-19 spread. Findings show that there are significant differences among stock market indices during the research period. Besides, stock market returns seem to be sensitive to Coronavirus new deaths. Moreover, this has been confirmed for March without any...

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Automatic Speech Segmentation Using Hybrid Wavelet Features and HMM

The Egyptian Journal of Language Engineering, Sep 16, 2016

In this research, a novel feature set is used to automatically segment speech signal. Automatic s... more In this research, a novel feature set is used to automatically segment speech signal. Automatic segmentation is very useful especially for large database. A hybrid features model is created from wavelet packet analysis and mel-scale is used to train Hidden Markov Model (HMM) for phone boundary detection. HMM is implemented using the Hidden Markov Model Toolkit (HTK).The database (Ked-TIMIT) is used for result verifications and Mel Frequency Cepstral Coefficients (MFCC) is used as reference for evaluating the results of the proposed Hybrid model. The results are categorized for vowels, consonants and short phones. Phone duration and start location are used as metrics to evaluate the system success rate. Success rate of 74% is achieved for consonant detection, 72% for vowel detection and 58% for short phone detection. Using the simple metric that relies only on boundary locations but ignoring duration, the achieved results are 92.5% for consonant detection, 90% for vowel detection and 77.5% for short phoneme detection. In addition to boundary detection the proposed hybrid model is utilized to compare newly developed features called Mel scale Best Tree Encoding (Mel-BTE) to the mostly used popular features MFCC along with all experiments using the same database. The relative results for Mel-BTE with respect to MFCC are 94.77% for consonant detection, 87.5% for vowel detection and 93.33% for short phoneme detection.

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In Situ Analysis of Deformation Mechanics of Constrained Cutting Toward Enhanced Material Removal

Journal of Manufacturing Science and Engineering, 2019

Chip formation in conventional cutting occurs by deformation that is only partially bounded by th... more Chip formation in conventional cutting occurs by deformation that is only partially bounded by the cutting tool. The unconstrained free surface makes it difficult to determine and to control the deformation of chip formation. The constrained cutting employs a constraining tool in the cutting process to confine the otherwise free surface and enable direct control of the chip formation deformation. The presented work is a study of the deformation mechanics of plane strain constrained cutting using high-speed imaging and digital image correlation (DIC) methods. For different constrained levels (including unconstrained free cutting), the material flow of chip formation is directly observed; the strain rate and strain in the chip as well as the subsurface region are quantified; cutting forces are measured; and surface finish is examined. The study shows that chip formation in constrained cutting can occur in two different deformation modes, i.e., simple shear and complex extrusion, depen...

The Light Years: Combined optical and environmental electron microscopy to visualize photonic processes with atomic-scale resolution

Microscopy and Microanalysis, 2019

Pearl Jam's hit, "The Light Years," declares "We were but stones, light made us stars." Bringing ... more Pearl Jam's hit, "The Light Years," declares "We were but stones, light made us stars." Bringing light to the transmission electron microscope (TEM) promises to transform our understanding of materials, enabling both direct observation of light-mediated processes and detection of optical emission with atomic scale resolution. To help achieve this goal, my lab is developing capabilities for concurrent optical and electron microscopy within an environmental TEM. This presentation will describe our efforts to visualize a variety of photochemical processes in situ with nanometer-to-atomic scale resolution. We focus in particular on i) observing photocatalytic phase transitions in nanoparticles; ii) detecting quantum light emission from two-dimensional materials; and iii) developing TEM-Raman with nanometer-scale resolution.

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Measurement of Dynamic Surface Tension of Suspension Sprays Based on Oscillating Jet Technique

Atomization and Sprays, 2019

Dynamic surface tension plays an important role in the atomization process and droplet formation.... more Dynamic surface tension plays an important role in the atomization process and droplet formation. We report measurement of dynamic surface tension of liquid suspensions in the range of submilliseconds time scales. An elliptic oscillating jet technique, combined with an analytical model, was applied to various types of liquids. First, distilled water and ethanol as pure liquids with constant surface tension were examined, followed by a mixture of distilled water and a surfactant (Triton X-100) at three different concentrations with variable surface tension. The final measurements were carried out on hydrophilic and hydrophobic solid particles, suspended in distilled water at different concentrations. The static surface tension of all liquids was measured with a du Nouy ring tensiometer and compared with the dynamic surface tension.

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Modal Analysis of a Vertical-Axis Darrieus Wind Turbine Blade with a Troposkein Shape

Topics in Modal Analysis & Testing, Volume 9, 2018

Darrieus wind turbines with troposkein shaped blades are an important type of vertical axis wind ... more Darrieus wind turbines with troposkein shaped blades are an important type of vertical axis wind turbines. When designing these turbines it is important to consider how vibrations may affect blade failure. In order to avoid resonance, the blade natural frequencies need to be determined. The goal of this research is to determine the blade free vibration mode shapes and modal frequencies, neglecting the variation of the upstream wind speed for simplicity. The blade modal vibration is studied numerically using ANSYS software, and analytically using thin-beam theory and an assumed modes method. Firstly, the analysis is performed on a 17 m diameter Sandia simplified troposkein shaped blade with a NACA 0015 airfoil. The first ten modes and the corresponding natural frequencies were calculated using ANSYS. The analysis was done for stationary and spinning blade at 54 rpm. The spin case compared very well to previous Sandia results. The same analysis was then applied to an ideal troposkein shaped blade, and a slightly modified cross section. Results show consistency across the blade shapes. The Sandia blade shape was studied analytically using thin-beam theory and an assumed modes method. Kinetic and potential energies were derived. Mass and stiffness matrices are formulated for the discretized model, to which modal analysis is applied. The natural frequencies were calculated analytically for same simplified Sandia blade shape used for finite element model under stationary condition. The results of the two methods were compared for consistency. Copyright by AMR FAWZY ABDEL HAKEEM SALEH 2017 iv I would like to dedicate this work to my mother and my father's soul, and my lovely wife v ACKNOWLEDGMENTS I would like to thank my advisor and my master Professor Brian Feeny for his endless technical and mental support and sharing his wisdom generously to influence me to go further. Without his dedication this research would have never existed. vi

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Penetration of Aerated Suspension Spray in a Gaseous Crossflow

Atomization and Sprays, 2018

The breakup of a suspension in the atomization process differs from that of a pure liquid by the ... more The breakup of a suspension in the atomization process differs from that of a pure liquid by the influence of the suspended particles on the fragmentation kinetics. In the suspension spraying process, different types of atomizers are used but clogging problems can occur due to the suspension properties. Effervescent atomizers have shown to be a good alternative to the conventional atomizers to solve clogging issues when liquids with a large variety of viscosity and density such as suspensions are atomized. In this study, effervescent atomization of suspensions in a crossflow of air is investigated experimentally. The tests have been performed at different liquid-to-air momentum flux ratios and different gas-to-liquid mass ratios. Different types of suspended solid particles, hydrophilic and hydrophobic, at different concentrations are tested. Shadowgraphy and image processing have been employed in order to capture the penetration height of the spray. New correlations have been developed to predict the spray penetration height of suspensions in crossflow for nonaerated and aerated liquid jets.

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Endovascular visual verification of anastomotic patency in coronary bypass

The Journal of thoracic and cardiovascular surgery, Jan 25, 2018

Endovascular visualization of coronary anastomosis. Central Message Endovascular visualization of... more

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Pilot randomized controlled trials in the orthopaedic surgery literature: a systematic review

BMC musculoskeletal disorders, Jan 24, 2018

The primary objective of this systematic review is to examine the characteristics of pilot random... more The primary objective of this systematic review is to examine the characteristics of pilot randomized controlled trials (RCTs) in the orthopaedic surgery literature, including the proportion framed as feasibility trials and those that lead to definitive RCTs. This review aim to answer the question of whether pilot RCTs lead to definitive RCTs, whilst investigating the quality, feasibility and overall publication trends of orthopaedic pilot trials. Pilot RCTs in the orthopaedic literature were identified from three electronic databases (EMBASE, MEDLINE, and Pubmed) searched from database inception to January 2018. Search criteria included the evaluation of at least one orthopaedic surgical intervention, research on humans, and publication in English. Two reviewers independently screened the pool of pilot trials, and conducted a search for corresponding definitive trials. Screened pilot RCTs were assessed for feasibility outcomes related to efficiency, cost, and/or timeliness of a lar...

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