Article
Green & Sustainable Science & Technology
William J. Cameron, Mussad M. Alzahrani, James Yule, Katie Shanks, K. S. Reddy, Tapas K. Mallick
Summary: With the increasing demand for renewable energy, concentrator photovoltaic thermal hybrids show great potential. By using multi-stage optics, the concentration ratio can be maximized to achieve high power outputs from multi-junction solar cells. A capable cooling system is necessary to prevent thermal stress and extract thermal energy. The primary objective of this study is to maximize the effective concentration ratio and optimize the energetic and exergetic efficiencies of the system.
Article
Energy & Fuels
Ehab Awad
Summary: Concentration photovoltaics utilize small-area solar cells to focus solar energy and achieve high efficiency at a reasonable cost. This study proposes an array of gold plasmonic concentrator cells that can nano-focus solar radiation to a spot size of 60 nm. It works over a wide solar energy bandwidth up to 2400 nm wavelength, surpassing the maximum operating wavelength of conventional solar cells. The concentrator consists of a coaxial waveguide and a tapered section for plasmonic nano-focusing, followed by a straight waveform section with integrated graphene metamaterial for optical absorption.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2023)
Article
Energy & Fuels
Ahmed Abdo, Takushi Saito, Shinichi Ookawara, Ali Radwan, Mahmoud Ahmed
Summary: The study compared the performance of different configurations of hybrid CPV-TEG systems and found that a new design achieved lower solar cell temperature and higher output power. Increasing heat flux to the TEG unit can boost total output power, highlighting the importance of selecting an effective heat sink to enhance electrical power output in hybrid systems.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Article
Thermodynamics
William J. Cameron, Mussad M. Alzahrani, James Yule, Katie Shanks, K. S. Reddy, Tapas K. Mallick
Summary: High concentration photovoltaic thermal hybrids are important for meeting energy demands, and a cooling system is necessary for optimal performance. This study develops a simulation model for a concentrated photovoltaic thermal hybrid system with serpentine-based cooling. The model has been validated through indoor experimentation and the effectiveness of cooling is evaluated based on thermal stresses. The double serpentine design and copper heat sink material demonstrated the highest performance and the recommended operating temperature was maintained.
APPLIED THERMAL ENGINEERING
(2023)
Article
Engineering, Chemical
Muhammad Ibrahim, Tareq Saeed
Summary: This article investigates the cooling of photovoltaic cells using a newly designed heatsink, finding that using nanofluids can increase heat transfer coefficient but also require more pumping power. Addition of alumina nanoparticles can improve thermal efficiency, while addition of copper oxide nanoparticles can reduce it.
JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS
(2021)
Article
Green & Sustainable Science & Technology
Husam Abdulrasool Hasan, Jenan S. Sherza, Jasim M. Mahdi, Hussein Togun, Azher M. Abed, Raed Khalid Ibrahim, Wahiba Yaici
Summary: In this study, a photovoltaic-thermal assembly with a water-cooled heat sink was designed and experimentally evaluated in the southern region of Iraq during summer. The results showed that the water-cooled heat sink effectively reduced the PV temperature and increased the electrical output.
Article
Thermodynamics
Asmaa Ahmed, Katie Shanks, Senthilarasu Sundaram, Tapas Mallick
Summary: The study compared new heat sink configurations based on a serpentine design with straight channel arrangement for high concentrator photovoltaic systems, finding that the serpentine design offers better cooling efficiency. At a concentration of 2000x, the serpentine design can maintain uniform temperature distribution in the system, achieving the highest energy and exergy efficiencies.
APPLIED THERMAL ENGINEERING
(2021)
Article
Energy & Fuels
Ramy Rabie, Mohamed Emam, Ahmed Elwardany, Shinichi Ookawara, Mahmoud Ahmed
Summary: This study aims to enhance the performance of concentrator photovoltaic cells integrated with passive heat sinks by utilizing combined aluminum fins and phase change materials (PCMs) for passive cooling. The developed design effectively improves the steady state temperature of solar cells and elongates the melting time of PCM materials. Traditional aluminum heat sinks and heat sinks with PCM are unable to control temperature effectively after the PCM materials have fully melted, while the new heat sink design can maintain a steady state temperature even after PCM complete melting.
Article
Thermodynamics
Mahdi Deymi-Dashtebayaz, Mojtaba Rezapour
Summary: Concentrator photovoltaic thermal system with Al2O3 nanofluid flow in porous channel under transient heat flux was analyzed in this study using finite element method. The numerical results showed good agreement with experimental data, with efficiency of the photovoltaic cell and first law efficiency increasing with Reynolds number, while second law efficiency decreasing.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Article
Thermodynamics
Masoumeh Azizi, Reza Tabatabaeekoloor, Ali Motevali, Seyed Reza Mousavi Seyedi
Summary: Considering the problems caused by non-renewable energy use, such as climate change and environmental destruction, it is necessary to utilize alternative and renewable energy sources, particularly solar power. This study analyzed the efficiency of a photovoltaic-thermal system with a parabolic trough concentrator and an eccentric receiver using different nano-fluids. The use of hybrid nano-fluids improved the filling coefficient and increased the electrical and thermal efficiencies, as well as the overall efficiency compared to pure water.
APPLIED THERMAL ENGINEERING
(2023)
Article
Green & Sustainable Science & Technology
Sajid Abbas, Yanping Yuan, Jinzhi Zhou, Atazaz Hassan, Min Yu, Ji Yasheng
Summary: Solar energy is a vital and promising renewable energy source, and solar photovoltaic/thermal systems (PV/T) have gained popularity for their ability to provide heat and electricity concurrently. The choice of base plate material and design parameters significantly impact the long-term reliability and performance of the PV/T system. Different base plate materials exhibit varied effects on the system's average temperature, electrical efficiency, thermal efficiency, and coefficient of performance (COP). Moreover, the packing factor of the photovoltaic module and the pitch of the heat pipe also play a crucial role in determining the system's performance.
Article
Construction & Building Technology
Zhiying Song, Jie Ji, Zhaomeng Li
Summary: The study investigates the combination of concentrated photovoltaics and direct-expansion solar-assisted heat pump, and finds that photovoltaic heat pump systems based on different concentrators show variations in electrical efficiency, coefficient of performance, and exergy efficiency.
ENERGY AND BUILDINGS
(2021)
Article
Chemistry, Physical
Adriana Elena Balan, Ali AL-Sharea, Esmaeil Jalali Lavasani, Eugenia Tanasa, Sanda Voinea, Bogdan Dobrica, Ioan Stamatin
Summary: In this study, multilayer graphene-paraffin composites with different graphene contents were prepared and characterized. The addition of graphene led to a decrease in energy storage capacity but a significant improvement in thermal conductivity. The composite material was used as a thermal heat sink for an embedded electronic processor, reducing the operating temperature by up to 20% and improving its performance.
Article
Thermodynamics
Hesham Zaghloul, Mohamed Emam, M. A. Abdelrahman, M. F. Abd Rabbo
Summary: The study focuses on passive cooling of triple-junction solar cells using straight fins heat sink and found that the fins are effective in reducing cell temperature and increasing system efficiency under high temperatures. Environmental factors such as ambient temperature, wind speed, and concentration ratio have significant effects on the cooling system's performance and carbon emission reduction.
ENERGY CONVERSION AND MANAGEMENT
(2021)
Article
Green & Sustainable Science & Technology
Bartlomiej Milewicz, Magdalena Bogacka, Krzysztof Pikon
Summary: The study focuses on the combination of silicon cell technology and dye concentrator, with experiments showing that using luminescent red PMMA as the concentrator resulted in the highest improvement in solar cell performance by an average of 1.21%. This demonstrates the potential for implementing a luminescent dye concentrator in solar electric technology.
Article
Mathematics
Sid Ahmed Ould Ahmed Mahmoud, El Moctar Ould Beiba, Fei Zuo
Summary: This work introduces and studies the concepts of n-quasi-m-hypercontractive and n-quasi-m-hyperexpansive operators on a Hilbert space. Some characterizations of these classes of operators are established, and many algebraic and spectral properties related to the members of these classes are extracted from these characterizations.
LINEAR & MULTILINEAR ALGEBRA
(2023)
Article
Engineering, Environmental
Tomoki Yasuda, Shinichi Ookawara, Shiro Yoshikawa, Hideyuki Matsumoto
Summary: This study proposes a framework for discovering porous materials that can improve the actual manufacturing process. By optimizing design variable recipes, ideal structures with high permeability and filtration efficiency have been obtained.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Thermodynamics
Mohamed G. Gado, Shinichi Ookawara, Hamdy Hassan
Summary: In this study, triply periodic minimal surface (TPMS) structures were used in adsorption cooling systems (ACSs) to improve performance. The use of metal TPMS-based structures significantly increased the thermal conductivity of the porous media/metal composite due to its large surface area. A CFD model was created and validated using Ansys Fluent. Five TPMS-based structures were compared with conventional Fins-based structures under different conditions. The results showed that TPMS structures had better cyclic cooling power (SCP) at certain porosities and can increase cooling capacity per day.
ENERGY CONVERSION AND MANAGEMENT
(2023)
Article
Materials Science, Multidisciplinary
M. Ismail, W. K. Zahra, Shinichi Ookawara, Hamdy Hassan
Summary: The performance of an air conditioning unit combined with phase change material as thermal energy storage in hot climates was investigated. A theoretical transient model was developed and numerically solved for plate and cylinder configurations. The results showed that the cylinder configuration had shorter discharging and charging durations compared to the plate configuration. Increasing the inlet air temperature decreased the exit air temperature and air conditioning coefficient of performance, but shortened the cooling time. Using phase change material with a lower melting temperature increased the melting time and exit air temperature. Mixing hybrid nanoparticles with phase change material had a short-term positive influence on air conditioning performance. The maximum power saving was 16.4% for the cylinder and 6.4% for the plate over a 2-hour and 10-hour working period, respectively.
Article
Clinical Neurology
Hani Chanbour, Lakshmi Suryateja Gangavarapu, Jeffrey W. Chen, Gabriel A. Bendfeldt, Iyan Younus, Mahmoud Ahmed, Steven G. Roth, Leo Y. Luo, Silky Chotai, Amir M. Abtahi, Byron F. Stephens, Scott L. Zuckerman
Summary: This study aims to investigate the incidence of unplanned readmission, identify associated risk factors, and determine the impact of unplanned readmission on long-term outcomes in patients undergoing surgery for cervical spine metastases. The results showed that 15% of patients experienced unplanned readmission, with 33% for surgical reasons and 67% for medical reasons. Preoperative radiation was associated with increased unplanned readmission rate, but readmission had no association with overall survival or local recurrence.
WORLD NEUROSURGERY
(2023)
Article
Energy & Fuels
Ramadan Gad, Hatem Mahmoud, Shinichi Ookawara, Hamdy Hassan
Summary: This study evaluates the thermal regulation of photovoltaic solar cells using a hybrid cooling system of flat heat pipes (HP) and phase change material (PCM), with and without hybrid nanoparticles. The evaluation is based on energetic, exergetic, economic, and environmental approaches. Results show that the HP-PCM cooling system outperforms natural solar panel cooling and the use of hybrid nanoparticles further enhances its performance. The proposed cooling system achieves significant reductions in operating temperature and improvements in solar panel efficiency compared to conventional systems. Additionally, the hybrid cooling system exhibits higher energy and exergy efficiency, as well as lower production costs, making it more effective and sustainable.
JOURNAL OF ENERGY STORAGE
(2023)
Article
Medicine, Research & Experimental
Mahmoud S. Ahmed, Ayman B. Farag, Ian N. Boys, Ping Wang, Ivan Menendez-Montes, Ngoc Uyen Nhi Nguyen, Jennifer L. Eitson, Maikke B. Ohlson, Wenchun Fan, Matthew B. McDougal, Katrina Mar, Suwannee Thet, Francisco Ortiz, Soo Young Kim, Ashley Solmonson, Noelle S. Williams, Andrew Lemoff, Ralph J. DeBerardinis, John W. Schoggins, Hesham A. Sadek
Summary: The study aimed to identify therapeutic options for the COVID-19 pandemic through structure-based drug repurposing. FDA-approved drugs were screened for their inhibitory effects against SARS-CoV-2's main protease enzyme (Mpro) substrate-binding pocket. Five promising candidates, including atovaquone and mebendazole, demonstrated antiviral activity against SARS-CoV-2. Atovaquone was also found to potentially inhibit viral replication by targeting host purine metabolism.
BIOMEDICINE & PHARMACOTHERAPY
(2023)
Article
Energy & Fuels
Shadrack K. Musyoka, Ahmed S. G. Khalil, Shinichi A. Ookawara, Ahmed E. Elwardany
Summary: In this experimental study, the effect of oxyfuel type, oxygen content, and blend volume on diesel engine performance, combustion, and emission characteristics was investigated. Seven fuel blends were tested and it was found that the additives had minimal effect on in-cylinder pressure and heat release rate. However, they were effective in reducing NOx emissions. Both fuel additives were suitable for CI engine at low blending ratios.
Article
Mechanics
Ahmed Elhanafy, Yasser Abuouf, Samir Elsagheer, Shinichi Ookawara, Mahmoud Ahmed
Summary: Diagnostic technology based on magnetic fields is commonly used in medicine, but exposure to strong electromagnetic fields has adverse effects on patients. This study investigates the effects of external uniform magnetic fields on blood flow in healthy and diseased cases, and determines safe values for field strength. A three-dimensional non-Newtonian flow model is developed to investigate the effects of the magnetic field on shear rate and hematocrit. Numerical simulations are conducted at different field strengths and orientations, and results demonstrate the dominant effect of the magnetic field in the Y-direction.
Article
Genetics & Heredity
Dalal Al-Sharshani, Dinesh Velayutham, Muthanna Samara, Reham Gazal, Ayman Al Haj Zen, Mohamed A. Ismail, Mahmoud Ahmed, Gheyath Nasrallah, Salma Younes, Nasser Rizk, Sara Hammuda, M. Walid Qoronfleh, Thomas Farrell, Hatem Zayed, Palli Valapila Abdulrouf, Manar AlDweik, John Paul Ben Silang, Alaa Rahhal, Rana Al-Jurf, Ahmed Mahfouz, Amar Salam, Hilal Al Rifai, Nader I. Al-Dewik
Summary: This study aimed to investigate the association between selected single nucleotide polymorphisms (SNPs) and dyslipidemia, as well as the increased susceptibility risks of cardiovascular diseases, type 2 diabetes mellitus, and non-alcoholic fatty liver disease. The results showed significant differences in genotypic frequencies of six SNPs between dyslipidemia patients and control individuals. These differences were found to be associated with gender, obesity, hypertension, and diabetes.
MOLECULAR GENETICS & GENOMIC MEDICINE
(2023)
Article
Oncology
Trang Huyen Lai, Mahmoud Ahmed, Jin Seok Hwang, Md Entaz Bahar, Trang Minh Pham, Jinsung Yang, Wanil Kim, Rizi Firman Maulidi, Dong-Kun Lee, Dong-Hee Kim, Hyun Joon Kim, Deok Ryong Kim
Summary: Breast cancer is a common tumor type in women with a high fatality rate due to metastasis. Raf kinase inhibitory protein (RKIP) is a potential metastasis suppressor candidate, but its expression is reduced or lost in aggressive cancer variants. This study explores the role of RKIP as an anti-metastatic gene using two breast cancer cell lines with different levels of RKIP expression. The findings suggest a potential strategy to reverse the metastatic capability of breast cancer cells by chemically manipulating RKIP expression.
FRONTIERS IN ONCOLOGY
(2023)
Article
Mathematics, Applied
Naeem Ahmad, E. S. Kamel, Sid Ahmed Ould Ahmed Mahmoud
Summary: In this work, we extend the concept of n-quasi-p-isometric operators from a single operator to multi-dimensional operators. We present new interesting results of these tuples of operators, which expand upon recently published works that focus on a single operator.
Article
Mining & Mineral Processing
Khaled Yassin, Mahmoud Ahmed, Mohamed Gamal Eldin Khalifa, Ayman Aly Hagrass
Summary: Dry magnetic separation is an effective technique for reducing iron in feldspar, especially in arid regions with limited water resources. This study conducted dry magnetic separation experiments on feldspar ore in the Wadi Umm Harjal area in Egypt, successfully removing iron content and improving the quality of the sample to meet industry specifications.
ARCHIVES OF MINING SCIENCES
(2023)
Article
Multidisciplinary Sciences
Sid Ahmed Ould Ahmed Mahmoud, Naeem Ahmad
Summary: In this paper, new classes of operators related to polynomially normal operators are introduced. The first class is m-quasi polynomially normal operators, which includes polynomially normal operators studied in recent papers. A bounded linear operator S is said to be an m-quasi polynomially normal operator if there exists a nontrivial polynomial P and a natural number m satisfying a certain equation. The second class is called polynomially C-normal operators, which includes C-normal operators studied in other papers. An operator S is called a polynomially C-normal operator if there exists a nontrivial polynomial P and a conjugation operator C satisfying a certain equation. The paper presents a detailed study of certain properties of the first class of operators and gives an introduction to the second class.
IRANIAN JOURNAL OF SCIENCE
(2023)
Article
Management
Mahmoud Ahmed
Summary: This paper investigates how women's representation on corporate boards affects financial reporting quality. The study finds that increasing women's representation on boards reduces undue CEO influence over the board and improves accounting quality. However, this effect is only significant in the long run and is attenuated for larger firms and larger boards.
INTERNATIONAL JOURNAL OF DISCLOSURE AND GOVERNANCE
(2023)
