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In electronic warfare, a robust perception of the surrounding signal environment is vital for optimal countermeasures. In this article, a new approach to a cognitive electronic support measures (COG-ESM) system based on computer vision techniques is proposed. The proposed approach overcomes the limitations of the traditional ESM when subjected to complex radar signals in a dense environment. The proposed approach relaxes the deinterleaving process of the concurrent radar signals to a 2D emitter localization in the time-frequency (TF) domain. Also, it integrates the modulation classification process with the 2D emitter localization in one process. This merge allows for sharing the hardware and software assets required for both processes. The proposed COG-ESM applies the state-of-the-art object detection networks to the TF images to localize and classify the individual radar emitters. The COG-ESM is trained to perform both 2D localization and modulation classification under the multipath effect, hence it is more robust under channel impairments. A new dataset of complex interleaved radar signals representing a dense signal environment under the multipath channel effect is introduced. Typical scenarios, signal parameters, and modulation types are considered in generating the dataset. That dataset is called wideband radar signals in dense environment (WBR-DE).

Symbolic control is an abstraction-based controller synthesis approach that provides, algorithmically, certifiable-by-construction controllers for cyber-physical systems. Symbolic control approaches usually assume that full-state information is available, which is not suitable for many real-world applications with partially observable states or output information. This article introduces a framework for output-feedback symbolic control. We propose relations between original systems and their symbolic models based on outputs. They enable designing symbolic controllers and refining them to enforce complex requirements on original systems. We provide an example methodology to synthesize and refine output-feedback symbolic controllers.

One of the most effective ways to deal with the effects of the current global energy crisis is to reduce energy consumption and rely energy management strategies. As a result, waste heat/energy recovery might be a helpful option for decreasing energy costs and environmental effect. It entails finding a practical way to apply any engineering system’s wasted heat where the percentage of wasted heat is too high in global. In this context, waste hot water is a rich source of wasted energy that, if recovered, can significantly cut down on the amount of electricity used worldwide. Within this framework, the present research paper provides a thorough analysis of Waste Water Heat Recovery Systems (WWHRS) in terms of performance, design, tools and applications. In addition, it is highlighting the key elements associated with WWHRS, including the wastewater sources and approaches used in the literature for waste water heat recovery. Moreover, the present paper demonstrates the effect of the heat recovery from the drain waste water on economically and discuss the technical barriers to using WWHRS. It will be demonstrated that the feasibility of recovering heat from waste water could decrease significantly the cost of energy consumption for residential or industrial application. In addition, the main tools that are used for heat recovery systems is the heat exchanger where various types are used and the thermal performance are strongly affected by the choice of heat exchangers. Moreover, based on the literature review, it is shown that the methods of studying the thermal performance of the heat recovery system are experimental and/or numerical and in some cases the study is performed analytically. Finally, all discussed and presented studies demonstrate that the WWHRS has a significant benefits and could be considered for new residential construction.

In this manuscript, a new concept of power generation from thermoelectric generators TEGs using the sun irradiation and two oil tanks, one hot and one cold, is proposed. It consists of two oil tanks separated by a plate covering several TEGs in series. The oil tank at the bottom of the system constitutes a cold convection condition for the TEGs plate; on the other hand, the upper oil tank accounts for a hot convection condition since its upper surface is transparent and therefore subjected to the sun irradiation that will heat up the oil. To test the feasibility of this concept, an appropriate thermal modeling is developed and associated parametric analysis was carried out. It shows that powers up to 242 W can be generated with a system having a hot oil tank height of 0.2 m along with a width and length of 2 m each.

The present work concerns an experimental study of the utilization of insulation and phase change material PCM in building structures. It particularly presents an efficient heating system modulated with thermal insulations and phase change materials where an appropriate experimental setup is devised to help in making energy management possible. The experimental setup consists of insulated and non-insulated room models that enable direct observation of different heat transfer results between a well-insulated room with PCM (paraffin wax) and a non-insulated room. The integrated heating-insulation-PCM set-up proved that it can work toward a more comfortable and efficient system where energy bills are 74% lower with an average improvement factor reaching 50% in comparison with the non-insulated room model.

In the present study, a solid biofuel based on Olive Pomace Waste (OPW) is manufactured in order to estimate the energy for heating water. A mechanical hydraulic press is constructed in order to create the block of OPW biofuel. To proceed, the standard form is burned to heat water in a tank where a thermocouple is placed to estimate the heating energy created by OPW blocks. Then, the standard OPW blocks are compared experimentally with other mixed biofuel blocks such as, waste Beeswax, oak charcoal, dry olive leaf and waste wood sawdust. It is shown that the standard OPW blocks could increase the temperature of 3 Liters of water to 34 °C whereas with the modified OPW mixed with other constituents temperatures up to 65 °C can be reached.

The development of different renewable energy techniques has shown their ability in limiting the environmental crisis and meeting future needs. In recent years many efforts have been made in order to produce hybrid systems that work on integrating renewable energy systems with thermoelectric generators (TEGs) in order to increase energy efficiency. This review attempts to discuss and summarize different configurations of hybridizing TEGs with different renewable energy sources (solar, fuel cell, biomass) underlying the concepts and approaches used to reach these hybridizations. This review will give necessary information about this type of hybridization and encourage for future research due to its promising results.

As the world deviates towards sustainability in buildings due to massive increase in energy demand, the effective integration of Phase Change Material (PCM) in buildings gained substantial attention. The capability of PCM in enhancing the thermal performance of buildings relies heavily on the encapsulation technique used as it is in direct link with enhancement techniques required for upgrading thermo-physical, chemical and environmental PCM properties. The current study reviews shortly recent literature involving PCM integration in buildings and highlights different encapsulation techniques used for their proper active and passive incorporation. It also summarizes recent methodologies of properties enhancements prior to encapsulation. Preliminary results reflect the importance of proper encapsulation using the five distinct techniques: direct mixing, imbibing, shape-stabilization, macro-encapsulation and micro-encapsulation. Commercialization of macro-encapsulated PCMs is dominant over other techniques, where micro/nano-encapsulation technique is still limited and requires further study being the most promising.

Reducing energy consumption has its direct impact on the worldwide environmental status. Smart energy processes must be adopted in order to enhance the reduction capacity of energy usage. In this view, both renewable energy as well as heat recovery strategy has been used in a wide range of engineering applications. With this in mind, hot wastewater is considered as a valuable source of energy that could be recovered. The present paper illustrates an overall review on the waste water heat recovery systems (WWHR). All systems can be classified based on their structural configuration and application. It has been shown that under some conditions a 50% energy could be stored or recovered using a heat recovery system. In addition, all systems are considered as an economic as well as environmental effective methods.

Phase change materials proved their capability of enhancing buildings’ thermal inertia and improving occupants’ thermal comfort. More attention was triggered by the scientific community as the use of thermal energy storage systems kept evolving in the building sector. Previous experimental investigations examined the effectiveness of enhanced macro-encapsulated coconut oil bio-based PCM integrated with underfloor water radiant heating system in two similar small-scale test facilities that are modular. The current study focuses on performing comparative energetic and economic analyses of the system performance in regards to: weather conditions, PCM application, PCM type and properties, and PCM plates position at the underfloor. Results highlighted the effectiveness of utilizing coconut oil PCM in active floor, and passive wall and roof as load shifting and energy savings were obtained. It was shown that with the combination of active and passive systems, annual savings of 227 USD can be achieved; and by placing the PCM underneath the heating system, energy saving of 393.5 kWh was achieved corresponding to 169 USD annual savings. However, 32 USD annual saving was achieved by the system integrated with paraffin wax compared to that integrated with cocoa-nut oil PCM. Finally, the PCM capability in cost savings was reflected with the payback periods being evaluated as follows: 6.82 years for experiment 2, 6.75 years for experiment 3 (both encountering load shifting), and 3.94 years for experiment 4 (encountering energy saving).

Currently, the world is perceiving a change-over from its existing conventional energy sources to a future with optimized and inventive energy sources. Nowadays, the world is more and more oriented to the use of renewable energy sources to decrease the consumption form the conventional energy sources in particular the fuel energy. In addition, the use of renewable energy source decrease the impact of the conventional energy on the environment. For all these reasons, researchers are currently focusing on studies that implement and innovate methods for the purpose of optimizing and increasing the efficiency of existing renewable energy sources. Of the proposed methods are the hybrid systems. These systems are applicable in both residential and industrial sectors. However, hybrid systems can be applied to renewable energy, wind energy, fuel cell, Desalination, Heating, Ventilating, and Air Conditioning, Engines, Electric Vehicles, Heat Pump, Redrying, PV cells, Engines, Solar Cells, and many other systems. In this context, the aim of the present paper is to provide a short recent review focusing on the types and applications of hybrid renewable energy systems and hybrid recovery energy systems that are applied in industrial and residential sectors. Moreover, the environmental impact, cost and the efficiency will also be presented and discussed.

This paper presents a simplified theoretical model for analyzing the temperature dynamics of photovoltaic (PV) modules. The model is built on an energy balance approach, considering solar irradiation as the primary energy input. It accounts for the conversion of solar power into electricity and the storage of thermal energy within the PV module, which subsequently increases the PV temperature leading to decay in its electrical efficiency. Heat loss from the top and bottom surfaces of the module, with variations for cooling techniques, is also included. The model is validated against three different experimental studies, demonstrating good agreement with the experimental temperature variations, with a maximum discrepancy ranging from 4 % to 16 %. This simplified model is then applied to two case studies: one representing typical daytime conditions and another simulating cold weather events. By comparing the PV temperature dynamics between the model and the experimental data, it is shown that the model accurately captures the dynamic response of the PV temperatures to changes in solar irradiation and ambient temperatures. Moreover, a parametric analysis is conducted to investigate the effects of key parameters on PV temperature and efficiency. Higher cooling rates from the bottom surface significantly boost electric power output, aligning closely with solar irradiance variations. Enhanced upper surface cooling, through increased convection, reduces PV temperature and thereby improves electric efficiency and power production. The PV temperature increases quasi-linearly with ambient temperature, especially at lower wind speeds, and decreases with higher wind speeds, eventually stabilizing at high values. Additionally, both ambient temperature and solar irradiance contribute to rising PV temperatures, with ambient temperature having a slightly greater effect. These findings underscore the critical role of cooling techniques in optimizing PV performance amidst varying environmental conditions.

This paper introduces a novel empirical correlation designed to predict the overall heat transfer coefficient (U) in concentric tube heat exchangers. The study utilizes a comprehensive dataset of 2700 data points from CFD simulations, examining the impact of critical variables including hot and cold fluid Reynolds numbers (Reh, Rec), Prandtl numbers (Prh, Prc), and heat exchanger dimensions (tube hydraulic diameter Dh, annular space hydraulic diameter Dc, and overall length L). The analysis incorporates a range of fluid combinations in the tube and annular sections – air–air, air–water, water-air, and water–water – across Reynolds number ranges from 1000 to 20000, covering both laminar and turbulent flow regimes. The correlation was developed using the Adam optimizer to minimize the Weighted Mean Squared Error (WMSE), achieving an impressive convergence to an average prediction error of 6.7% compared to actual Uvalues. The model categorizes flow into four distinct categories, each corresponding to a combination of flow patterns in the tube and annular spaces regimes – Laminar–Laminar, Laminar–Turbulent, Turbulent–Laminar, and Turbulent–Turbulent – integrating both hydrodynamic and thermal entry effects to enhance prediction accuracy. Rigorous error analysis revealed a median error of 5.18%, substantially outperforming existing models. Notably, 10% of the predictions deviate by less than 1%, with 90th percentile errors staying below 15%. Parameters were finely tuned through extensive numerical simulations, ensuring accurate application of the correlation across diverse operational conditions. The study concludes by highlighting the model’s potential to significantly enhance the design and efficiency of heat exchangers and proposes future enhancements to further improve its predictive accuracy.

Vortex generators are very effective tools in increasing heat transfer from one region to another, especially by convection, and appear to be a very promising concept to be coupled with heat recovery systems. On the other hand, Thermoelectric Generators (TEGs) are devices able to convert differences in temperature into electrical power using the Seebeck effect, the main advantage being working on high or even low differences in temperature. These TEG modules could be very effective tools in the hybridization of heat recovery systems. In this context, the present paper suggests an innovative system that couples three important energy axes together such as Heat recovery, TEGs, and Vortex generators. The current study employs a TEG in a rectangular channel to analyze the influence of the TEG on the flow and the effect of the effect of flow regime on producing electric power in order to assess the viability of this recently proposed concept. The investigation is conducted by varying the Reynolds number in a range of five values: 1000, 2000, 4000, 7000, and 10,000, applying six different configurations. Consequently, the results show that several factors affect the electrical power generated by TEG such as the emplacement, angle of attack, and absence/presence of vortex generators. On the other side, the heat recovered by the flow is affected by the TEG and Re, where the highest heat recovery is achieved at Re= 10,000 for configuration 4 with electrical power of 7.4 W, and for configuration 5 heat recovered by the flow of 1913 W. Besides, it was concluded that TEGs decreased the losses in both hot and cold sides by 1.42 times.

Background: People all around the world are affected by primary liver cancers like hepatocellular carcinoma (HCC), which is usually associated with cirrhosis. Early HCC detection is crucial for better prognosis, but effective biomarkers are still needed. Hepcidin, a hormone-regulating iron homeostasis, has been implicated in liver diseases. In this study, blood hepcidin levels were evaluated in cirrhotic individuals as a possible biomarker for HCC. Methods: There were three groups involved in this case-control study: cirrhotic patients with no HCC (group I), cirrhotic patients diagnosed with HCC (group II), and healthy controls (group III). Clinical and laboratory data, such as those from tests indicating the liver function, hepcidin levels, and imaging, were all analyzed using a number of statistical tests. Results: When compared to those with cirrhosis, serum hepcidin levels were significantly lower in HCC patients, but there was no significant difference statistically between the two studies involved: cirrhotic groups and the controls. Serum alpha-fetoprotein (AFP) was also significantly greater in HCC patients. Conclusions: The start and progression of liver diseases, such as HCC in cirrhotic people, appear to be influenced by hepcidin. It can be utilized as a potential HCC biomarker when cirrhotic liver is present, despite the fact that it cannot be used to diagnose cirrhosis by itself.

Cogeneration systems, exploiting waste heat sources, have emerged as crucial solutions in decreasing energy consumption and mitigating CO2 emissions across diverse industrial domains. This study delves into the innovative integration of multiple waste heat recovery (MWHR) mechanisms with thermoelectric generators (TEGs) within industrial contexts, with a specific emphasis on harnessing exhaust gas heat. Through meticulous investigation, six distinct configurations of TEG placement covering three unique systems were examined to expose their influence on overall system efficacy. Findings clarify a deep correlation between TEG positioning and system performance, with TEGs strategically positioned in close to heat sources, particularly along the inner walls of exhaust pipes, demonstrating the most auspicious outcomes in terms of power generation. Furthermore, the study reveals notable metrics, including a maximum power efficiency of 0.11 W per TEG and a water heat flow rate peaking at 5114 W. However, a comprehensive analysis underscores the imperative for interpreting the primary mechanisms governing TEG placement's impact on system performance, alongside defining the practical implications of the observed power efficiency and water heat flow rate. These empirical insights underscore the transformative potential of WHR-TEG interactions in optimizing energy utilization within industrial ecosystems, highlighting the request for further research actions aimed at implementation strategies and sustainability benchmarks.

In this paper, a unique method for using thermoelectric generators (TEGs) to generate electricity is introduced, a technique that makes use of a cold oil tank and hot exhaust gases from generators. A set of TEGs and an integrated cold oil tank are connected to the diesel generator as part of the suggested design. A pertinent thermal modeling was designed and a thorough parametric study was carried out to show the validity of this innovative concept. The parametric study has demonstrated that when the generator power and the thickness to thermal conductivity ratio of each TEG in the system are increased, the temperature differential in each TEG module and the power produced by the assembly of TEGs both exhibit linear increases. The length of the TEG plate and the height of the exhaust gas duct cause an exponential increase in the temperature differential across each TEG module. The TEG assembly's power output increases linearly with TEG surface length and decreases exponentially with exhaust gas duct height. Using an exhaust gas duct height of 0.05 m, and a TEGs plate length of 1 m, the parametric study showed that power generation of up to 2778 W is feasible under the predetermined circumstances of a diesel generator with an output of 125 kW. When compared to a conventional setup, the new hybrid generator in this scenario may be able to increase power generation by up to 2.22 %.

Purpose: To determine the prevalence of keratoconus (KC) among children with ocular allergy.Methods: A cross-sectional study was conducted on all children presenting with ocular allergic disease from September 2017 to September 2018. All study participants were subjected to history taking (a specially designed questionnaire), routine ophthalmological examination, and corneal tomography.Results: A total of 79% of the study patients had vernal keratoconjunctivitis (VKC) while the remaining had perennial allergic conjunctivitis (10%), seasonal allergic conjunctivitis (9%) and atopic keratoconjunctivitis (2%). Manifest KC was seen in 7% of cases, suspect KC was found in 27% of cases, and 66% had no evidence of KC. For the manifest KC, 56% had clinical signs, while 44% were diagnosed by tomography. For the purpose of statistical analysis, the cohort was divided into group KC (manifest or suspicious KC) and group non-KC (no KC). The mean age was 11.2 years in group KC, and 9 years in group non-KC (p< 0.001). The mean duration of allergic symptoms was 3.75 years in group KC, and 2.5 years in group non-KC (p= 0.001). The mean duration of eye rubbing was 2.5 years in group KC, and 0.83 years in group non-KC (p= 0.02). Systemic atopy was present in 35.3% of group KC, and in 12.5% in group non-KC (p= 0.005).Conclusion: The overall prevalence of KC was 34%. Risk factors for the development of KC in patients with ocular allergy were age, duration of symptoms specially eye rubbing, systemic atopy and VKC. Tomographic diagnosis of KC can be present in absence of clinical signs.

Solar radiation is captured by photovoltaic (PV) panels, which use it to create electricity. However, an overabundance of photons striking the PV's surface raises its temperature, which lowers its efficiency. These days, cooling solar panels is very important, and research on these methods is widely available in the literature. Thus, the study field's problems truly lie in developing new or improved methods for doing the same tasks. The goal of this work is to further boost the efficiency of photovoltaic (PV) panels beyond what can be achieved with PCM and free/forced convection alone. To do this, phase change materials (PCM) are cooled using both free and forced convection. In accordance with the latitude of Lebanon's Bekaa Valley, four cooling techniques are experimentally investigated. A photovoltaic panel using phase-change material (PCM) with copper and aluminum wires in a 70 %–20 %–10 % mass ratio (CPCM-PV), respectively, is the first cooling method. In the second approach, four 5 cm long fins are fixed under free convection using the same combination of aluminum fins inside the PCM container while preserving the same ratio (IEF-PCM-Free-PV). The third technique is the same as the second but with forced convection (IEF-PCM-Forced-PV), while the fourth technique uses an aluminum finned plate with 16 finned plates under forced convection (F-Forced-PV). IEF-PCM-Forced-PV showed the most relative increases in efficiency rate of energy dissipated of 20.36 % and 62.24 %, respectively, as compared to the regular PV panel, according to the results. F-Forced-PV, IEF-PCM-Free-PV, and CPCM-PV showed an increase in relative efficiency of 16.87 %, 6.3 %, and 3.9 % respectively, and correspondingly, these enhancements were accompanied by an increase in energy dissipation of 55.80 %, 44.85 %, and 41.18 % for each system. Economically, the IEF-PCM-Forced-PV had the highest total yearly savings of $17.87 with a payback period of 1.9 years. An appropriate transient energy balance is conducted and permitted to demonstrate clearly the transient behavior of the system under the various cooling techniques. Finally, the percentage of enhancement using the newly suggested composite PCM with internal and external fins under forced convection is compared to the enhancement found in the literature for various classical techniques and shows greater potential for further enhancement of the PV performance.

The global research community has increasingly focused on sustainable energy solutions to combat the environmental challenges posed by extensive fossil fuel consumption. This paper presents a new simple approach to enhance the electric efficiency of photovoltaic (PV) panels through efficient cooling techniques using simple parallel water pipes on the back of the PV panel. Additionally, the waste heat generated during this process is harnessed as a valuable heat source for residential hot water systems. Experimental measurements were conducted on both the reference PV panels without cooling and the PV/T system equipped with cooling pipes. A comprehensive energy analysis was performed to compare their performance. The results demonstrate that the cooled PV/T system exhibits consistently higher electric efficiency due to effective cooling by about 10%, resulting in surface temperature reduction and enhanced performance. The system also demonstrates a significant improvement in waste heat recovery, making it a practical and promising choice for sustainable energy applications.

This study delves into exploring and comparing various cooling technologies for PV panels, with a special focus on revealing the harmful effect of excessive heat absorption on solar energy efficiency. Effective temperature management and dissipation of excess heat are essential to protect the integrity of PV panels and improve power generation. With a strong emphasis on the importance of experimental setups, this comprehensive research examines the methodologies and cooling methods used across a wide range of experimental studies, illustrating the complexities of data collection and analysis. Supported by schematic illustrations depicting various experimental setups, this study demystifies the complexities inherent in distinct PV cooling methods. Furthermore, the research extends beyond experimentation to include a comprehensive examination of the energy and economic aspects associated with various cooling technologies, including the calculation and presentation of energy efficiency ratios. It is worth noting that the results confirm the superiority of passive cooling techniques, including heat sinks (43%), PCM (25), evaporation techniques (36%), and spray cooling systems (54%), in contrast to active cooling methods, as indicated by their net energy efficiency ratios. Passive cooling is advantageous for its low maintenance and cost-effectiveness, whereas active cooling, though effective in hot climates and enhancing PV efficiency, incurs higher initial costs and maintenance requirements. The novelty of this research lies in its detailed classification of cooling techniques and the specific materials used for each method, coupled with a thorough examination of the measuring tools employed. Furthermore, this study includes a comprehensive comparative analysis based on energy and economic aspects, alongside the advantages and disadvantages of each cooling technique. These invaluable insights hold the potential to revolutionize the development of efficient and dependable cooling strategies for PV systems, thereby elevating the feasibility and sustainability of solar energy as a pivotal cornerstone in our future energy landscape.

All of scientific findings, economic considerations, public awareness, and technology progress highlighted together the rising importance of energy management to avoid various environmental issues. Electric vehicles (EVs) nowadays play an essential role in lowering the environmental effect of transportation in general, notably greenhouse gas emissions. Knowing that the majority of modern EVs are powered by lithium-ion batteries that have significant benefits such as high energy density, prolonged durability, and quick charging. However, temperature changes have a substantial impact on li-ion batteries performance making them having a reduced capacity, longevity, and safety. Due to the mentioned challenge, this study aims to provide an understanding of the growing environment of lithium-ion batteries (LIB) thermal management against the rising demand for EVs and the challenges these vehicles face due to climate variations. To achieve its objective, this study offers an in-depth review of experimental and computational investigations that were performed between 2020 and 2023 for various heating and cooling systems. Paper findings reflect a dynamic balance in research focus between heating and cooling technologies, which demonstrates the field's adaptation to the upcoming challenges. The yearly research distribution demonstrates the adaptive nature of the research overview with a significant increase in efforts in 2023. Furthermore, the distribution of study methodologies shows a synergy between experimental and computational approaches with stressing a comprehensive knowledge of LIB thermal behavior. As a result, this article serves as a comprehensive yet informative reference for researchers and industry professionals through providing an overview of recent achievements and trends in the fundamental area of the lithium-ion batteries thermal management for electric vehicle technology.

•Numerical simulations of laminar flows around heated bumped surface cylinders with square, triangular, and dimple shapes are performed.•The effects of the bump's location and Re on the imposed pressure on the cylinder and heat transfer enhancement are studied.•A bumped-surface cylinder has a distinct vortex shedding frequency compared to a smooth cylinder.•The magnitude of the Nu number changes with the location of the bump.•Apart from the bump shape, the minimum and maximum Nu occur at θ = 45 and = 90 °, respectively.

Utilizing a cooling technique can help prevent overheating, which can have a detrimental impact on the performance of solar panels. Instead of using a water cooling system that requires a pump, an alternative method uses the return air from a Heating, Ventilating, and Air Conditioning (HVAC) system often utilized in industrial settings. An air cooling system that uses the HVAC system's return air was previously recommended by the co-authors of the current study. Using numerical methods, they carried out a feasibility analysis and showed how a variety of parameters, such as the convection coefficient and the flow type (natural or forced), might affect the output power (efficiency) of the system. As a continuation of the previous study, the present study examines two cooling scenarios to further their past findings. Three different configurations for external flow were tested: cooling the upper and lower surfaces of the PV with exhaust air, installing a vortex generator at the leading edge of the lower surface while relying on natural convection for the upper part, and installing a vortex generator on both the upper and lower surfaces. The efficiency of the PV system increases from 11 % to 18 % with an increase in cooling demand from 0 to 160 kW with solar radiation of 500 W/m2. Efficiency was improved by generating turbulent flow at the leading edge of the panel. While using an internal flow on the bottom surface, the system's efficiency increased as the PV module's length increased.

This paper presents a heat recovery system (HRS) that exploits the chimney`s exhaust gasses to heat water. Optimization of a waste HRS called the "multi tube tank," as suggested by Khaled et al., is performed through experimental means. The design is described in detail and constructed, after which it is tested. Investigation of the impact of altering the head shape on the performance of the system is performed by constructing two distinct heads, one cylindrical (Cyl) and one conical (Con). Results indicate that the conical head (ConH) outperforms the cylindrical head (CylH). Specifically, in 275 min, the water temperature increases to a maximum of 59 °C with the CylH, while the ConH can raise the water temperature to 68 °C. Moreover, in 400 min, the ConH system can augment the water temperature up to 80 °C. Furthermore, economic and environmental analyses are performed, which show that the ConH system can save approximately 16 $/month more than the CylH system when the system is exploited 140 times/month for 275 min. Additionally, the payback period for the ConH system is about half that of the CylH system (6 months). Finally, the ConH system can reduce emissions of CO2gas by 2 tons/year more than the CylH system when utilized 140 times/month.

The increasing global demand for renewable energy sources underscores the significance of Solar Water Heating Systems (SWHS), emphasizing the need for thorough research and analysis in this domain. SWHS play a pivotal role in addressing energy efficiency and environmental sustainability, making it imperative to conduct in-depth studies on their utilization. Hence, this paper aims to provide a comprehensive overview of SWHS. It starts by explaining the principles behind these systems, including their components and classification. Moreover, this review consolidates various studies that have been conducted on SWHS to highlight both their advantages and disadvantages. Additionally, a case study is conducted in which it takes into consideration important economic and environmental factors. In particular, it focuses on several scenarios present in Lebanon such as family homes, schools, restaurants hotels and gyms to estimate potential cost savings achieved through implementing SWHS as opposed to relying solely on electric heaters. Furthermore, this investigation also examines the corresponding payback period associated with adopting SWHS along with assessing the significant reduction in carbon dioxide emissions possible if these systems were widely implemented. The findings of the study demonstrate that there is a direct correlation between the extent to which SWHS are utilized and both the payback period and reduction in CO2emissions. It was observed that when SWHS are used more frequently, with a high percentage of time (Pr=0.9), significant advantages can be achieved. For instance, for different types of establishments such as family homes, schools, restaurants, hotels, and gyms, it was estimated that average payback periods would be 14.2 years, 4.6 years, 9.2 years, 4.4 years, and 5.3 years, respectively. These results indicate that adopting a greater dependency on SWHSs not only leads to quicker cost recovery but also significantly contributes towards reducing carbon dioxide emissions. The analysis reveals that the yearly decrease in carbon dioxide emissions per individual is 0.16 t within a household, 0.016 t per student in an educational institution, 0.04 t per customer within a dining establishment, 0.37 t for each occupied bed in a hotel accommodation, and 0.11 t per individual at a gym. This paper serves as guidelines to SWH community. Additionally, it adds a practical insights into economic and environmental issues relevant to both Lebanon and countries with similar climates.

Vortex generators (VGs) have been extensively studied and utilized in multifunctional heat exchangers/reactors due to their remarkable ability to create coherent flow structures and streamwise vortices. These characteristics significantly enhance the mixing and heat transfer performance in laminar and turbulent flow regimes. With the advancement of computational power, VG shape optimization has become feasible, leading to the discovery of various optimized shapes in the literature for different Reynolds numbers. In this paper, the response surface polynomial method is employed as a surrogate model to optimize the angle of attack and inclination angle of a delta winglet VG at a Reynolds number of 4,600. The potential applications of these optimized designs are diverse, particularly in scenarios that require cooling or heating. Some examples include photovoltaic (PV) panel cooling, waste heat recovery in hybrid PV/solar water heating systems, energy-efficient HVAC systems, and thermal management in electric vehicles. To achieve this objective, Computational Fluid Dynamics (CFD) simulations are conducted to compute the thermal performance factor of each VG design at various values of attack and inclination angles. By enhancing mixing and heat transfer capabilities, this design can have a substantial impact on various renewable energy applications, contributing to a greener and more sustainable future. The highest thermal enhancement factor of 1.15 is found to be achieved for an inclination angle of −45°and an angle of attack of 35°. This means that optimized VG enhances heat transfer by 15% compared to empty channel flow, while maintaining the same pumping power.

In light of the environmental concerns associated with the misuse of fossil fuels and the increasing consumption of energy, heat recovery systems have become an essential option for conserving energy. In this study, an innovative design that couples a highly efficient vortex generator-based heat exchanger with a new multi-drain water application for 48 accommodations is suggested. A numerical study is done by varying the flow rate and investigating the effect on the heat transfer, overall heat transfer, and thermal enhancement factor. Besides, the economic and environmental impacts of the system are studied to investigate its sustainability. Four types of input energy are studied: coal, diesel, gas, and electricity. Results show that the design provides a temperature increase of 3.5 to 7.5 °C of cold water, consequently, the daily environmental savings are up to 0.87 € (for gas), 1.74 € (for diesel), 4.63 € (for coal), 17.63 € (for electricity US) and 2.26 € (for electricity FR). Besides, the daily economical savings are up to 7.54 $, 8.63 $, 4.63 $, and 15.07 $ respectively with a payback period of around 0.61, 1.2, 1.42, and 2.89 years for gas, diesel, coal, and electricity respectively.

Scientists all over the world are striving to improve the efficiency of the photovoltaic panel by many different techniques to maintain its temperature in the range of PV operation. In this paper a new technique of cooling photovoltaic panels PVs is suggested and investigated theoretically based on experimental behaviour obtained for a single PV panel. This technique is based on a flipping method consisting of two PV panels A and B installed at the opposite direction of each other. Initially Panel A is active, after certain time when the temperature of panel A increases above a prescribed limit, the system rotates the panels to become panel B the active panel. This technique is based on previous experiment and studied at two different flipping temperatures (36°C, 42°C). Results showed that as the flipping temperature decrease, the operating temperature of the PV will decrease, which results in higher power generation. There is a significant enhancement in the power per unit area that can be a solution for using PVs in restricted areas.

The last decade has witnessed significant attention on networked control systems (NCSs) due to their ubiquitous presence in industrial applications, and in the particular case of wireless NCSs, because of their architectural flexibility and low installation and maintenance costs. In wireless NCSs, the communication between sensors, controllers, and actuators is supported by a communication channel that is likely to introduce variable communication delays, packet losses, limited bandwidth, and other practical nonidealities leading to numerous technical challenges. Although stability properties of NCSs have been investigated extensively in the literature, results for NCSs under more complex and general objectives, and, in particular, results dealing with verification or controller synthesis for logical specifications, are much more limited. This paper investigates how to address such complex objectives by constructively deriving symbolic models of NCSs, while encompassing the mentioned network nonidealities. The obtained abstracted (symbolic) models can then be employed to synthesize hybrid controllers enforcing rich logical specifications over the concrete NCS models. Examples of such general specifications include properties expressed as formulas in linear temporal logic or as automata on infinite strings. We thus provide a general synthesis framework that can be flexibly adapted to a number of NCS setups. We illustrate the effectiveness of the results over some case studies.

Pulmonary hypertension is the major cardiac complication of chronic obstructive pulmonary diseases (COPD). Also it is considered as a predictor of mortality independent of the pulmonary obstruction severity. Due to different methods of diagnosis and lack of the gold standard Right heart catheterization (RHC), diagnosis of PH in COPD patients could be missed and hence its treatment may be deficient which could impair the quality of life and lead to poor prognosis. So the aim of this work is to detect the frequency of pulmonary hypertension (PH) among stable COPD patients, and to evaluate the possible correlation of PH with the severity of the disease.

Air heating is currently an essential part in many industrial and residential applications. One of its disadvantages is the higher energy consumption. Therefore, the renewable energy sources present now different solutions in order to decrease the energy consumption and to enhance the performance of existing systems by the hybridization. For these reasons the energy management at all levels became one of the most important research. In this context, the present paper proposes a design for a solar air heater that could be applied in more than one application. A modelling and an experimental study are presented. The presented solar air heating system allows reducing the energy consumption by replacing completely or partially an electrical air heating system. In addition, an in-house code is developed in order to simulate the suggested solar air heater and to study its performance. The experimental setup is implemented and designed to validate the developed code. Accordingly, a relative error of the modelling is estimated and it varies between 4 and 14%. Finally, the system is evaluated economically and environmentally by assessing the effect of replacing the electrical heating system of a fruit dryer by the suggested solar heating. It has been shown that adopting such system allows to save up to $106 per year and to reduce about 2045 kg of carbon dioxide emission.

No reliable data whether periprocedural myocardial necrosis (PPN) has same poor prognostic value as periprocedural myocardial infarction (PMI) or not. We aimed to assess the impact of PPN on short term clinical outcome.

In this paper, a contemporary concept that is based on dividing, by means of multi-passages, the water flow rate of water-air cross flow heat exchangers (HXs) is proposed. The thermal performance of water-air cross flow heat exchangers varies through a rationale function when the water flow rate changes. The new concept is based on dividing high flow rates of water entering a water-flow heat exchanger into several passages. This fragmentation prevents keeping the thermal performance from being nearly constant at high flow rates which lead to increasing the thermal performance globally. The feasibility of this concept was examined and had been proven through calculations on a double passage heat exchanger using an in-house two-dimensional computational code that had been developed and validated to evaluate the thermal performance of Heat Exchangers (HX) using a prescribed set of parameters. It was observed that the thermal performance increases rapidly with the water flow rates at low flow rates and become nearly constant at high flow rates. Furthermore, results revealed that the implementation of the novel concept can increase the thermal performance of a standard water-air cross flow heat exchanger by up to 25.7 %. The enhancement is more significant at high mean air velocities and low water flow rates.

This paper presents a simulation model and parametric analysis of a parabolic trough thermoelectric hybrid system. The structure of the system under study mainly consists of a parabolic trough with a triangular receiver equipped with a photovoltaic layer and thermoelectric generators at its back. A thermal model of this system is described and simulated using MATLAB software. The thermal model is utilized to investigate the system performance by performing a parametric analysis. This analysis is conducted to analyze the influence of several parameters such as fluid and air velocities, fluid channel diameter, receiver side length, and the thermal conductivity of the thermoelectric generator on the performance of the system. The results reveal that the thermal efficiency increases noticeably by 6% and 21% when increasing the dimensionless tube diameter from 0.5 to 1 and the dimensionless receiver side length from 1.67 to 8.33, respectively. It decreases significantly by 23% when rising the air Reynolds number from 1.90  ×  106to 18.98  ×  106, whereas the fluid velocity and thermoelectric generators thermal conductivity have a negligible effect on it. Furthermore, the electric efficiency is enhanced considerably by 36% and 14% when augmenting the dimensionless tube diameter from 0.5 to 1 and the fluid Reynolds number from 5982 to 19940 respectively. However, it is noticeably reduced by 13% when increasing the dimensionless receiver side length from 1.67 to 8.33, while it is affected negligibly when varying the air velocity (air Reynolds number) and the thermal conductivity of thermoelectric generators.

A new concept of power generation from thermoelectric generators TEGs using the hot exhaust gas of boilers and a cold oil tank is proposed. The suggested concept consists of a flow of exhaust gas of boilers and cold oil in a tank separated by a plate comprising several TEGs in series. The oil tank at the bottom of the system constitutes the cold convection condition for the TEG plate and the upper hot exhaust gas flow constitutes the hot convection condition. Accordingly, a temperature gradient is created across the thickness of the TEGs, which play the role of a separation plate, and converted to an electrical power. To justify the feasibility of this new concept, a suitable thermal modeling is developed and the associated parametric analysis is carried out. The parametric analysis reveals that powers up to 622 W can be generated with a system having a space heating load of 200 kW, an exhaust gas duct height of 0.05 m, and a TEG plate length of 1 m. The temperature difference across each TEG module decreases exponentially when the TEGs plate length increases and decreases exponentially when the exhaust gas duct height increases.

Food addiction (FA) is a recent term used to describe craving for food in addition to functional impairment. FA has not been thoroughly studied in adolescents, so the aim of this study was to assess its presence in Egyptian adolescents and its relations to some psychiatric correlates; anxiety and depression.

The current work aims to present systematic information about encrusting fouling bryozoan fauna collected from Hurghada, Egyptian Red Sea. During September 2015, scraped fouling samples were collected from beneath the jetty of the National Institute of Oceanography and Fisheries, Red Sea branch, Egypt. Five species of encrusting bryozoan are recorded in the present study. These are Celleporaria aperta, Parasmittina egyptiaca, Watersipora subtorquata, Hippopodina feegeensisand Scorpiodinipora costulata, affiliating to 5 families, which belong to the suborder Neocheilostomina. Parasmittina egyptiaca, Hippopodina feegeensisand Scorpiodinipora costulataare new records from Hurghada, Red Sea waters. Descriptions of the recorded species are given with illustrative photos as well as their geographical distribution and habitats.