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Abstract Background Biofilm formation has a crucial role in the cariogenic virulence of Streptococcus mutans, which leads to resistance to common antibacterials. The antimicrobial resistance crisis has led to increased research about traditional natural products. Purpose Quercus infectoria extract (QI extract) and nano hydrogels containing QI extract (QI-NH) and tannic acid (TA-NH) were evaluated against this pathogen. Methods QI extract was analyzed by HPLC and the physiological characteristics of nanohydrogels were assessed by SEM, FTIR, zeta potential, DLS and determination of release kinetics and encapsulation efficiency. Determination of MIC and MBC of the material and their anti-biofilm effect was done by the microtiter method and on the extracted tooth surface. The properties of extracts and nano hydrogels in the expression of genes codifying glucosyltransferases (gtfB, gtfC and gtfD) and glucan binding protein B (gbpB) were quantified. Their toxicity was tested by the MTT method against the KB cell line. Results According to HPLC, 55.18% of QI extract contained TA. The encapsulation efficiency of QI-NH and TA-NH was equal to 60% and 80%, respectively. SEM and FTIR exhibited that QI extract and TA were successfully entrapped in the networks resulting from the chemical bonding of chitosan and TPP. The average size of QI-NH and TA-NH was 70.45 and 58.43 nm, and their zeta potential was 6.17 ± 2.58 and 0.25 ± 0.03 mv, respectively. PDI

This research sought to investigate the association between the occurrence of the pvl and mecA genes and the strength of biofilm formation, as well as to assess the efficacy of vancomycin and ceftaroline against Staphylococcus aureus strains obtained from skin and soft tissue infections (SSTIs). A total of 134 S. aureus isolates were collected from SSTI patients and identified through standard microbiological techniques. Vancomycin and ceftaroline susceptibility testing were performed using the agar dilution and disc diffusion methods, respectively. PCR analysis was conducted to identify the nuc, mecA, and pvl genes. Biofilm production was measured using the tissue culture plate method. Methicillin-resistant S. aureus (MRSA) represented 58.2 % of the isolates. All isolates displayed biofilm-forming capability, with 10.4 % classified as high-grade biofilm producers, 85.7 % of which were positive for the mecA gene (P = 0.02). 16.4 % of the isolates had pvl gene and 59 % of PVL-positive strains identified as MRSA. Most of the low-grade biofilm producers had the pvl gene (P = 0.03). Vancomycin susceptibility was observed in 98.5 % of isolates, with an MIC₅₀ of 1 μg/mL in 51.4 % of cases. Among MRSA strains, 1.4 % exhibited intermediate resistance to vancomycin, with MICs between 4 and 8 μg/mL. No resistance to ceftaroline was found. The results demonstrate a significant association between biofilm production strength and the occurrence of the mecA and pvl genes; mecA correlated with increased biofilm production, while pvl was associated with lower biofilm levels. These findings offer valuable insights for future studies, suggesting that ceftaroline could be an effective alternative to vancomycin for treating MRSA-related SSTIs, particularly given the increasing resistance to vancomycin.

Abstract Humidification and dehumidification (HDH) desalination units compared with the other thermal desalination systems have relative advantages due to working under ambient pressure and low temperatures and are more attractive. In this research, the application of an HDH desalination unit with indirect‐contact of air and water streams in a steam power plant is investigated. To increase the energy efficiency of the system, a closed air cycle has been considered. Also, by application of the closed water cycle in the humidifier, the recovery rate of the desalination unit increases according to the concentration of discharge flow. The flow rate of boilers blowdown in the studied steam power plant is around 2.2 kg/s and can be used as a unique source of required thermal energy in the desalination system to produce freshwater from power plant chemical effluents. On the basis of the available cooling water (30 m3/day), this stream is considered as the limiting flow in the modeling. The detailed design of different parts of the desalination unit, including the humidification tower, condensers, wet air circulation fans, the required pumps, and the heat exchanger, is presented in this study. The maximum production of freshwater and the minimum energy intensity are obtained for the circulating air flow rate of 4 kg/s. By 14% recovery of lost steam in the power plant, 20.8 m3/h of desalinated water is produced. The gain output ratio and the energy intensity of the system are 1.025 and 2201 kJ/L, respectively. The production cost with the proposed indirect‐constant HDH system is equal to 0.56 $/m3 of freshwater.

Abstract Objective The ongoing outbreak of the respiratory disease coronavirus disease 2019 (COVID‐19) is currently presenting a major global health threat. This pandemic is unprecedented in recent human history. The objective of this study was to examine the relationship between cycle quantitation (Cq) and laboratory parameters in COVID‐19 patients, aiming to determine if Cq levels can provide valuable insights into the COVID‐19 disease. Methods This study involved 234 participants who were divided into case and control groups. Real‐time PCR tests were used to diagnose COVID‐19 cases in the study participants. Blood tests, including complete blood count, C‐reactive protein (CRP), erythrocyte sedimentation rate (ESR), lactate dehydrogenase (LDH), D‐dimer, IgG, and IgM, were also conducted. Statistical analysis was performed using SPSS 22 software. Results The findings showed that COVID‐19‐positive cases had significantly higher levels of the neutrophil‐to‐lymphocyte ratio (NLR), platelet‐to‐lymphocyte ratio (PLR), D‐dimer, ESR, CRP, and LDH compared to normal cases. Additionally, the case group had significantly lower lymphocyte and platelet counts. There was a statistically significant positive correlation between Cq levels and lymphocyte count (r = .124, p = .014). Conversely, there was a statistically significant inverse correlation between Cq levels and NLR (r = −.208, p = .017). Furthermore, the evaluation of hematological, inflammatory, and biochemical indexes in COVID‐19 patients using the receiver‐operating characteristics curve demonstrated statistically appropriate sensitivity and specificity. Conclusion Our outcomes indicated a significant association between Cq levels and PLR, NLR, D‐dimer, CRP, and ESR in COVID‐19 patients. Consequently, including the report of laboratory parameters alongside Cq values offers a promising prognosis.

Abstract Drinking water is a crucial need for human survival and solar stills (SSs) have emerged as a cost‐effective solution to meet this need from an economic point of view. In this work, the working of various SSs, their productivity factors, and various devices that can be integrated to improve their efficiency have been studied. The conversion of saline water into freshwater water using SSs has the potential to address the issue of drinking water. This study highlights the importance of SSs as a viable and sustainable solution for drinking water access. On the basis of various parameters correlating to the performance of the SSs, energy, exergy, economics, exergoeconomics, exergoenvironment, and enviroeconomics analysis has been analyzed in this study. To improve the performance and sustainability of SSs, various combinations were studied. These combinations include SSs with different nanoparticle coatings, phase‐change materials, photovoltaic modules, external condensers, wick materials, and reflectors. It is concluded that a comprehensive framework that integrates thermodynamic, economic, and environmental criteria can guide the development of more efficient and sustainable SS technologies.

Electric vehicles (EV) played an important role fighting greenhouse gas emissions that contributed to global warming. The construction of the charging pile, which was called as the ''gas station'' of EV, developed rapidly. The charging speed of the charging piles was shorted rapidly, which was a challenge for the heat dissipation system of the charging pile. In order to reduce the operation temperature of the charging pile, this paper proposed a fin and ultra-thin heat pipes (UTHPs) hybrid heat dissipation system for the direct-current (DC) charging pile. The L-shaped ultra-thin flattened heat pipe with ultra-high thermal conductivity was adopted to reduce the spreading thermal resistance. ICEPAK software was used to simulate the temperature and flow profiles of the new design. And various factors that affected the heat dissipation performance of the system were explored. Simulation results showed that the system had excellent heat dissipation capacity and achieved good temperature uniformity. Rather than solely relied on the fans, this new design efficiently dissipated heat with a lower fan load and less energy consumption.

Exhaust gases from the smelting furnace have high temperature and mass flow rate, and there is huge potential to use them for energy-related purposes such as electricity generation, cooling and heating. Utilization of the gases for energy-related purposes would lead to fuel savings and emissions reduction. To use this potential, it is necessary to design proper systems and cycles and apply a heat recovery unit. Several technologies are useable for heat recovery depending on the characteristics of exhaust gases, such as their mass flow rate, temperature and compositions. Due to the higher potential of combined heating, cooling and power (CCHP) generation systems compared with the systems with a single output, a CCHP is designed and investigated in the present study by consideration of the specifications of the exhaust gases. The applied system in this study comprises a Supercritical CO2 (SCO2) cycle, heat exchanger and single-stage absorption chiller for simultaneous heating, cooling and power production. Engineering Equation Solver (EES) is employed to model the proposed system by considering the properties of the flows and characteristics of the components. To get deep insight into the effective parameters on the outputs of the designed system, the impact of three factors, namely the mass flow rate of the gases, the effectiveness of heat exchanger and temperature of exhaust gases, are analyzed and investigated by the implementation of sensitivity analysis. As one of the main conclusions, it is found that an increment in the mass flow rate of exhaust gases from 30 kg/s to 70 kg/s causes augmentation in the power generation from 2037 kW to 4754 kW. Furthermore, exergy analysis is carried out, and it is found that an increase in the temperature or mass flow rate of exhaust gases or a decrease in the effectiveness of heat exchangers would lead to decrement in the exergy efficiency of the system. According to the performed sensitivity analysis, the mass flow rate of exhaust gases has the most remarkable influence on the heating and cycle-generated power among the considered factors.

Abstract Background and Aims Inflammation is one of the immune thrombocytopenic purpura (ITP)'s aggravating elements due to inflammatory cells' function. This study aims to identify and evaluate hematological inflammatory parameters, including neutrophil‐to‐lymphocyte ratio (NLR), platelet‐to‐lymphocyte ratio (PLR), and hemoglobin‐to‐platelet ratio (HPR), in patients with ITP compared to the control group. Methods We retrospectively analyzed the profile of 190 ITP patients from August 2019 to January 2021 at Imam Reza Hospital of Mashhad, Iran, along with 100 healthy individuals who had no ITP‐related clinical or laboratory symptoms. Immune cell counts, NLR, PLR, and HPR were calculated using the complete blood count at the time of diagnosis and after the treatment. The results were analyzed through MedCalc, SPSS software, and the receiver operating characteristic curve. Results The result showed that white blood cell (WBC) and neutrophil counts were higher in ITP patients (WBC: p: 0.001, neutrophil: p: 0.001), and conversely, platelet and lymphocyte counts were higher in the control group compared to ITP patients (platelets: p: 0.001, lymphocytes: p: 0.001). The indices analysis between the two groups revealed that NLR was significantly increased in ITP patients (p: 0.001), but PLR was significantly reduced in ITP patients (with the mean platelet count of 23.44 ± 35.26 × 109/L) compared to the control group (with the mean platelet count of 234.04 ± 55.88 × 109/L). The HPR index also significantly increased in ITP patients (p: 0.001). Conclusion An increase in NLR, PLR, and a decrease in HPR can be considered a valuable diagnostic algorithm in patients with ITP.

The aim of the present study was to evaluate the role of extracellular death factor (EDF) derived from Escherichia coli in the induction of programmed cell death (PCD) in methicillin-resistant and -susceptible Staphylococcus aureus (MRSA and MSSA). The confirmation of bacterial strains as well as the minimum inhibitory concentration (MIC) test were performed according to CLSI, 2022. The extraction and efficacy determination of EDF as well as the CFU assessment were done. The expression of mazE and mazF gens in different conditions was evaluated by Real-time PCR. The likely formation of persister cells from MRSA and MSSA, and the possible synthesis of EDF in old cultures of these pathogens was evaluated, as well. The combination of EDF of two E. coli strains and sub-MIC rifampin reduced the CFUs of MRSA and MSSA strains in mid-logarithmic growth phase while increased the expression of mazF several times more than mazE gene. The expression of these genes in different conditions were unlike. EDF was produced in the old cultures of MRSA and MSSA. The supernatant of E. coli 25922 was more powerful than the clinical strain ones to decrease the CFUs of the MRSA and MSSA. The EDF derived from E. coli in combination with sub-MIC rifampin could induce PCD in MRSA and MSSA through activation of the MazEF system. This phenomenon could be exploited as a non-antibiotic treatment candidate to combat the infections caused by the antibiotic-resistant pathogens. However, more studies should be performed in this regard.

Mini solar flat plate collectors have gained traction due to their cost-effectiveness, high efficiency in converting solar radiation to heat energy, and versatility in residential and commercial applications, offering long lifespans with minimal maintenance. Optimizing the thermal performance of solar flat plate collectors using numerical simulations helps enhance their efficiency, making them even more appealing for small-scale heating and hot water applications. This study investigates the flow behavior and temperature distribution of air within a small-sized solar collector (286 × 800 × 70 mm) and optimizes its design for achieving the highest outlet air temperature. The optimization process included varying geometric parameters, such as the wavy structure hole diameter, and considering a range of operating conditions, including ambient conditions and solar intensities. This analysis aimed to understand the flow behavior and temperature distributions within the solar collector. The numerical studies provided valuable insights into the thermal and flow characteristics of the collector. The velocity distribution of the fluid within the collector aided in understanding the flow behavior, optimizing the flow path to minimize pressure drop, and maximizing heat transfer. Additionally, calculations were performed to determine total useful heat, outlet temperatures, and efficiencies. The study also discusses the optimal design and operating conditions for the collector.

Heating and thermal comfort have remarkable share of final energy consumption. Until now, most of the demand for heating applications in buildings is supplied by fossil fuels and electrical technologies. Concerning the exhaustion of fossil fuels in the future and the environmental problems related to their consumption, making use of renewable energy sources can be a practical alternative. On this point, solar energy is an appropriate source to be applied for heating by utilizing different technologies. The function and output of solar heaters depends on numerous factors, and this causes difficulties in the prediction of their performance and modelling. In this scenario, intelligent techniques are helpful and have been used by several scholars in recent years. This paper reviews proposed models for the prediction of the performance of different solar heaters. The literature review reveals that artificial neural Networks represent one of the most used approaches for the performance prediction of solar heaters; however, other intelligent techniques, namely support vector machines, have been used for this purpose too. Moreover, it is found that these methods have the ability to predict with great precision by applying the appropriate approach and architecture. In addition, it can be noted that the function of the models generated based on intelligent techniques are associated with some elements such as the employed function and architecture of the model.

Background & Objectives: Beta-thalassemia is one of the complex diseases that causes many social and economic problems for the patient and his family. This study aimed to investigate factors influencing the birth of thalassemia (intermedia or major) in family members with thalassemia major in Sistan and Baluchistan province. Materials & Methods: This descriptive-analytical study was conducted by census sampling on 48 families of thalassemia major patients with at least two children with thalassemia (intermedia or major) in their members. Data were collected through direct interviews and a review of patients' documents. The results were analyzed by SPSS (version 22) and Mann-Whitney U, Independent t-test, Wilcoxon, and Chi-square tests. Results: In this study, statistical evaluations showed that the birth of thalassemia in family members with thalassemia major whose mothers are housewives was 100% and in families that had no premarital counseling was 91.7%. There was a significant relationship between variables related to mothers' awareness of thalassemia, including their place of residence and Sistani and Baluchestani ethnics, and the birth of thalassemia in family members with thalassemia major (in both cases, P-value = 0.05); However, there was no significant relationship between other variables related to mothers' awareness such as age groups and maternal education with the birth of thalassemia in family members with thalassemia major (P-Value = 0.98 and P-Value = 0.22, respectively). Conclusion: Informing and educating before marriage for high-risk families with thalassemia children, as well as financial support for low-income families can inform parents, prevent the birth of thalassemia, and improve the quality of life of these patients.

Abstract Background This study aimed to evaluate the effect of vitamin D3 supplementation on body composition and anthropometric measures of nursing mothers. Methods In a double-blind, randomized clinical trial, 90 nursing mothers with overweight or obesity were randomized into three groups for 12 weeks: two groups of vitamin D3 supplementation (2000 IU/d (VD1), n = 32 and 4000 IU/d (VD2), n = 29) and placebo (PL) group (n = 29). The information on body composition was obtained using the body impedance analysis (BIA) method. Serum 25-Hydroxy vitamin D (25(OH) D), Intact Parathyroid Hormone (iPTH), calcium, and phosphorus were measured before and after the intervention. Data were analyzed based on the intention-to-treat (ITT) method. Two-way repeated measure ANOVA (mixed ANOVA) was applied to assess whether the mean changes in the results from baseline to 12 weeks differ in the three groups. Results There was a significant increase in the serum 25(OH) D concentration in the VD2 group compared to VD1 and PL groups (mean change (MC), 12.3 ng/ml; 95% CI, 9.4/15.0, p-value

In this study a 2D cubic chamber model filled with paraffin is analyzed with and without the inclusion of magnetic Fe3O4 nanoparticles at concentrations of 0.5, 1, 1.5 and 2 wt%, and an external magnetic field of intensities 0.005, 0.01, 0.015 and 0.02 T. It is ascertained that adding magnetic nanoparticles leads the horizontal temperature gradient to be reduced owing to increments in thermal conductivity. Additionally, this feature is found to be accelerated by applying an external magnetic field, which shapes highly conductive cluster formations of nanoparticles. However, since the increase in nanoparticle concentration and magnetic intensity increases the composite viscosity, there is an optimum configuration while applying both schemes. As such, the addition of 1 wt% nanoparticles provides the best results, as the melting time is reduced up to 25% compared to pure paraffin. Meanwhile, the melting time of a 1 wt% nanoparticle-containing phase change material (PCM) in the presence of an external magnetic field is improved up to 24% compared to the case with no external magnetic field. Also, the heat transfer coefficient of a 1 wt% nanoparticle-containing PCM both with and without an external magnetic field is also staggeringly enhanced compared to pure paraffin. Good correspondence with experimental data was achieved.

Introduction: Given the role of chronic inflammation in developing GDM (gestational diabetes mellitus), investigating hematological inflammatory indicators such as platelet-to-lymphocyte ratio (PLR), hemoglobin-to-platelet ratio (HPR), and other blood biomarkers can be helpful in GDM patients. The present study was conducted aimed to evaluate the hematological inflammatory indicators of women with GDM compared to the control group. Methods: In this retrospective study, the profiles of 300 pregnant women with a definite diagnosis of GDM admitted to Mohebbe Yas Hospital (Tehran) from 2019 to 2021 were investigated. In this study, the absolute number of blood cells and other hematological parameters were evaluated in separate groups of diabetic and normal pregnant mothers. The sensitivity and specificity of each statistically significant variable were determined by ROC curve analysis. Data were analyzed by SPSS (version 22) and Mann-Whitney U, Independent t-test, Wilcoxon, and Chi-square tests. P˂0.05 was considered statistically significant. Results: In terms of absolute lymphocyte count (ALC), the results of comparison between GDM and normal groups showed that this index had a sensitivity of 84.07% and a specificity of 37.98% in the diagnosis of GDM patients, and it was statistically significant (p= 0.022). The absolute neutrophil count (ANC) index had a sensitivity of 66.78% and a specificity of 53.49%, which was statistically significant (p= 0.012). The PLR index had a sensitivity of 54.08% and a specificity of 66.67% (p0.05). Conclusion: This study showed that in GDM patients, ALC and ANC indices decrease and PLR increases. To improve the screening process of high-risk pregnant women for GDM, the predictive value of each of these indices in the incidence of GDM can be investigated in future studies.

The price of constructing hydrogen generation units is very high and sometimes it is not possible to build them in the desired location, so the transfer of hydrogen from the hydrogen generation system to the units that need it is justified. Since the storage of hydrogen gas needs a large volume and its transportation is very complex, so if hydrogen is stored in liquid form, this problem can be resolved. In transporting liquid hydrogen (LH2) over long distances, owing to heat transfer to the environment, the LH2 vaporizes, forming boil-off gas (BOG). Herein, in lieu of only reliquifying the BOG, this study proposes and assesses a system employing the BOG partially as feed for a novel liquefaction process, and also the remaining utilized in a proton exchange membrane fuel cell (PEMFC) to generate power. Using the cold energy of the onsite liquid oxygen utility of the LH2 cargo vessel, the mixed refrigerant liquefaction cycle is further cooled down. In this regard, by using 130 kg/h BOG as input, 60.37 kg/h of liquid hydrogen is produced and the rest enters PEMFC with 552.7 kg/h oxygen to produce 1592 kW of power. The total thermal efficiency of the integrated system and electrical efficiency of the PEMFC is 83.18% and 68.76%, respectively. Regarding the liquefaction cycle, its specific power consumption (SPC) and coefficient of performance (COP) were achieved at 3.203 kWh/kgLH 2 and 0.1876, respectively. The results of exergy analysis show that the exergy destruction of the whole system is 937.4 kW and also its exergy efficiency is calculated to be 58.38%. Exergoeconomic and Markov analyses have also been applied to the integrated system. Also, by changing the important parameters of PEMFC, its optimal performance has been extracted.

The drinkable water storages shortage is one of the main obstacles that many societies are envisaged with. In addition, the water content of humid air is known as the main storage of drinkable water for the future. In this paper, the energy and exergy analysis of a solar driven atmospheric water generator which contains an absorption refrigeration cycle coupled to a compound parabolic collector is performed. The mathematical model of the proposed system is developed in MATLAB software. In the solar thermal system provided in this paper, the storage tank is employed for extending the working hours of the system leading to improvement of total water generation rate. Furthermore, the performance of the system is evaluated in various climates included arid, semi-arid and Mediterranean, and for this purpose three cities of Iran named Bandar Abbas, Ramsar and Tehran were selected. Moreover, by comparing the water production in various months during the year, the highest value of water production during the year is held by Bandar Abbas city leading to owning the lowest values of specific power consumption and specific collector area. The maximum rate of water production of proposed system is approximately 400 lit per month in tropical climates with specific energy consumption of 3 kWh/lit. Based on the results of exergy analysis of whole system, the most exergy destruction rate belongs to compound parabolic collector component, therefore, large amount of energy is wasted through compound parabolic collector which can be recovered for generation of chilled water. Moreover, the impacts of geographical and environmental parameters on the energy and exergy efficiencies of the atmospheric water generator are also assessed.

A new engine patent was awarded to Meletis and Georgiou in 1998. The engine is with vane rotor and the rotor is fully balanced and symmetric. It also has an exhaust gas recirculation (EGR) process. Symmetric rotor mechanism leads much smother running, and EGR process makes working fluid (WF) preheated before entering to compression stage which provides very high temperature after compression so that the compression ignition can be implemented. An irreversible (practical) Meletis–Georgiou heat engine cycle (IMGC) model with irreversible heat transfer loss (IHTL) as well as internal irreversibility loss (IIL) is built by applying finite-time thermodynamic theory. A non-linear relation between specific heat (NLRSH) of WF and WF’s temperature is considered. Analytical expressions of output work and thermal efficiency versus compression ratio (CPR) of the IMGC are derived. Performance analyses and optimizations of the IMGC are done using numerical calculations. Both of output work and thermal efficiency of the IMGC with NLRSH of WF and its temperature are larger than those with constant specific heat of WF at the same CPR. There are an optimal CPR make output work approaches maximum and another optimal CPR make thermal efficiency approaches maximum. The range of maximum output and maximum thermal efficiency gives the design optimization criterion for the IMGC, which means the thermodynamic trade-off optimization with the two performance indicators for the IMGC. Effect features of IHTL, IIL, NLRSH and other parameters on the optimal performances and optimization criterion are analyzed.

Considering the high installation cost of renewable systems and reliance on weather conditions, as well as high energy consumption in post-combustion carbon capture system, the use of the combined method can assist to achieve net-zero carbon emission. Carbon dioxide (CO2) capturing based on renewable energies is introduced as a practical emission-control tool and method to tackle environmental, economic, and social challenges. In this study, to present a novel and optimized CO2 capture system an integrated layout is presented to facile and efficient utilization of fossil fuels. This layout is comprised of two sub-sections: a combined gas and steam power production unit, and a geothermal-assisted CO2 capture unit. The presented layout is simulated and its performance is evaluated concerning exergy analysis. In addition, sensitivity analysis is carried out to show the effect of changes in some influential parameters on the overall performance of the designed layout. Obtained results show that the presented scheme obtains a total thermal efficiency of 43.11%. In addition, the heat duty in the CO2 capture section is obtained to be 3.689 MJ/kgCO2 expressing the effectiveness of the presented scheme for the CO2 post-production procedure. The exergy study demonstrates that maximum irreversibility happens in the combustion chamber (47.43%), heat exchangers (35.05%), and turbines (6.257%). Besides, sensitivity assessments declare that the natural gas flow rate and the number of stages in the stripper column are the two crucial variables that also influence other functional parameters. The overall thermal efficiency increases up to 0.4331 and heat duty in the carbon dioxide capture section decreases to 3.725 MJ/kgCO2 when the stage number in the stripper column increases from 5 to 19.

The rising demand for electricity, along with the need to minimize carbon footprints, has motivated academics to investigate the flexible and efficient integration of energy conversion technologies. A novel hybrid power generation system based on environmentally friendly and cost-effective technologies to recover the waste heat of a working gas turbine is designed and assessed in different scenarios of multi-objective optimization from energy, exergy, exergoeconomic, and environmental (4E) perspectives. In the proposed system, a steam methane reformer and a water gas shift reactor are utilized for hydrogen production, while a polymer electrolyte membrane fuel cell (PEMFC) and steam/organic Rankine cycles are run for generating additional power. Aspen Plus, in conjunction with Fortran, Microsoft Excel, and MATLAB, is used to model and simulate the designed plant. The response surface methodology (RSM) is utilized to determine accurate surrogate models to describe the evaluation criteria, and the Non-dominated Sorting Genetic Algorithm II technique is employed to seek the optimal conditions. Moreover, TOPSIS and LINMAP decision-making approaches are used to find the best final solution among Pareto frontiers. The analysis of variance (ANOVA) and sensitivity analysis are also applied to evaluate the importance of the design variables. In this regard, three single-objective optimizations and four multi-objective optimization scenarios based on the maximization of the ecological coefficient of performance (ECOP) and the minimization of CO2emissions and total system product cost (Ċp) are carried out. It is demonstrated that the system’s evaluation criteria have the highest and lowest sensitivity to the variation of reformer temperature and ORC pressure, respectively. From the triple-objective optimization procedure, the decision variables including reformer temperature, ORC pressure, Rankine cycle I pressure, and Rankine cycle II pressure are 544 °C, 4.35 bar, 158.12 bar, and 52.82 bar, respectively. At these conditions, the total hybrid system’s energy efficiency, exergy efficiency, exergy destruction, net generated power, and total investment cost rate are 45.96%, 46.83%, 215.72 MW, 203.67 MW, and 9791 $/h, respectively. The findings of this paper conclude that it is necessary to address all objective functions simultaneously in the system’s ultimate optimum design. Furthermore, the objective of this paper becomes even more apparent when there is no choice but to cut greenhouse gas emissions while also addressing the rising global energy demand.

Abstract Background Occult hepatitis B infection (OBI) is a transfusion‐transmitted infection. Although, screening the hepatitis B virus among blood donors can play an important role in increasing the health of blood products, OBI screening in blood transfusion centers is still a challenge. This review study aimed to appraise the challenges of OBI screening and its associated do's and don'ts in blood transfusion centers. Methods In this review study, a search was conducted on the electronic databases of PubMed, Web of Science, Scopus, Ovid, Irandoc, and Magiran from January 1996 to December 2020. Also, cross‐sectional studies that determined the prevalence of OBI or anti‐HBc were included in the study. In addition, studies with incomplete data on the prevalence of OBI were excluded. Results The prevalence of OBI varies among Iranian blood donors. The rates reported by blood transfusion centers of Mashhad, Ahvaz, and Tehran were 0%, and Isfahan, Shiraz, and Kerman were 0.9%, 0.08%, and 2.36%, respectively. In areas with high prevalence of hepatitis B virus, OBI screening only by anti‐HBc test led to the exemption of blood donors from donating blood. Avoiding OBI screening also effected the risk of virus transmission to blood recipients. Plasma products had a higher risk (85%) of virus transmission. Conclusions Determining an appropriate screening strategy based on prevalence status, the cost‐effectiveness of screening tests, and the policies of each blood transfusion center is essential.

Background: Breast cancer (BC) is the most common malignancy in women worldwide. The methylation status of MyoD1, a tumor suppressor gene, is enrolled in various cancers, i.e., BC. Various studies showed the impact of MyoD1 epigenetic dysregulation in BC. This study aimed to investigate the methylation status and expression level of MyoD1 in BC patients and its association with the expression of DNMT1. Materials and Methods: This case-control study was conducted on 30 cases (pathology-confirmed ductal carcinoma) and 18 controls (fibroadenoma and fibrocystic masses), referred to Velayat Hospital, Qazvin, Iran. The expression of the MyoD1 and DNMT1 and the promoter methylation of the MyoD1 were evaluated in tissue blocks of BC patient masses using qRT-PCR and MS-PCR assays, respectively. SPSS 24.0 was used to analyze the data. Results: The MyoD1 promoter is hypermethylated in BC patients compared to controls (p =0.001). The expression level of MyoD1 in BC patients was significantly reduced compared to controls (fold change =0.13, p =0.042). In addition, in BC patients, the reduced expression level of MyoD1 was significantly associated with methylation of the MyoD1 promoter (p =0.001). There is no significant difference between the expression level of DNMT1 in BC patients and controls (p =0.197). A significant association is found between the expression of DNMT1 and the methylation status of the MyoD1 promoter (p =0.038). Discussion: The expression level of MyoD1 is affected by the methylation status of the promoter of this gene. Moreover, the expression level and methylation status of MyoD1 are correlated with clinical parameters.

Abstract The use of different energy storage materials can have a high effect on the water productivity of solar desalination. This study evaluates the impact of magnetic powders on modified solar still (MPSS) performance and compares the results with conventional solar still (CSS). Black iron oxide magnetic powder was selected to increase solar radiation absorption. The black iron magnetic powder simultaneously acts as a thermal storage material and a porous absorber medium. The thermal energy stored in the magnetic powder improved the performance of the MPSS during peak solar irradiation hours, resulting in higher productivity. The results showed that the thermal performance of MPSS was higher than CSS. The MPSS exhibited a 39.8% higher evaporative and 14.5% higher convective heat transfer rate compared with CSS. Results showed that the cumulative water productivity of MPSS was 31.2% greater than CSS. Also, the energy and exergy efficiencies of MPSS were improved by 18.9% and 19.04%, respectively, compared with CSS. Moreover, the predicted payback period in MPSS and CSS were 3.2 and 4.3 months. Additionally, the CO2 reduction of MPSS was improved by approximately 45.53% compared with that of CSS. The results also showed that the exergoeconomic parameter of MPSS and CSS with energy base was equal to 33.1 and 24.56 kWh/$, respectively.

The attachment of turbulators, such as baffles, fins, ribs, bars, and blocks, inside the thermal solar receiver ducts, is among the most effective mechanisms for important thermal exchange by creating the turbulence, extending the trajectory of the flow, increasing the surface of heat exchange, forcing recycling cells, and hence a high thermal exchange. The solar finned and baffled heat exchangers are employed in a wide application interval, and it is important to examine the design of a duct for this configuration of the flow field and its effect on the heat transport phenomenon. In This study, dynamic field simulations are reported in horizontal rectangular form ducts, using three obstacles with oil HTF (heat transfer fluid). Two various finned and baffled duct configurations are treated, i.e., case (A) with one fin and two baffles, and case (B) with two fins and one baffle. Different hydrodynamic fields, i.e., X-velocity and Y-speed, as well as various X-velocity profiles in many flow stations, related to Re value, are analyzed. A computational approach is applied in order to simulate the oil flow, using finite volume (FV) integration method, SIMPLE discretization algorithm, QUICK interpolation scheme, Standard k-epsilon turbulence model, and ANSYS FLUENT 12.0 software. Simulation results reported an unstable flow structure, with powerful recycling cells, on the backsides of each fin and baffle, as a result of fluid detachment at their upper front sharp edges, in both studied models (A and B). As expected, the first duct model, i.e., Case A, has better X- and Y-velocity values, due to its large recirculation regions. In This paper, many physical phenomena, such as the turbulence, instability, flow separation, and the appearance of reverse secondary currents, are reported. As its data confirmed by many previous numerical and experimental results, the suggested new models of finned and baffled heat exchangers filled with high thermal conductivity oil, allow an improvement in the dynamic thermal-energy behavior of many thermal devices such as flat plate solar collectors.

Background: Mycoplasma hominis (M. hominis) is an important cause of bacterial infections of the genital tract. Macrolides are the first selective agents used to treat mycoplasma infections. However, widespread use of macrolides has led to a rapid and global emergence of macrolide-resistant strains. We evaluated macrolide resistance in M. hominisisolated from endocervical specimens of patients who referred to Ibn Sina Infertility Centre in Tehran, Iran.Materials and Methods: In this cross-sectional descriptive-analytical study, 160 samples of Dacron endocervix swabs (80 infertile patient samples and 80 healthy controls) were collected and transferred to the laboratory. All samples were cultured in liquid pleuropneumonia-like organisms (PPLO) broth and PPLO agar solid media. After culturing and genome extraction, polymerase chain reaction (PCR) was performed using specific primers. Then, minimum inhibitory concentration (MIC) was obtained using the broth microdilution method. The MIC was recorded and reported for all samples positive for M. hominis against erythromycin.Results: From the 160 endocervical specimens cultured in PPLO agar medium, 19 cases (23.75%) were positive. A total of 35 cases (42.5%) were positive using specific primers of M. hominis species. MIC results from all samples positive for M. hominis were measured against erythromycin. All of the M. hominis samples were resistant to erythromycin.Conclusion: The results of the present study showed that a significant percentage of infertile women were infected with M. hominis. Also, MIC results from the broth microdilution method indicated that all strains positive for M. hominis were also resistant to erythromycin.

Considering the waste of fresh water in a 256 MW steam power plant located in the southeast of Iran, and to compensate a part of its water consumption, a humidification-dehumidification (HD) desalination system is proposed. Because of sedimentation problems in indirect-contact HD systems, in this research, the application of direct-contact HD method to recover the effluent stream in a steam power plant is presented. Considering unit cross-sectional area for HD towers and based on primary results of the modeling, up to 119 lit/hr can be produced when the height of both humidifier and dehumidifier is 1.8 m and the flow rate of air is 0.7 kg/s. Three different scenarios based on (I) full capacity of available steam from the blowdown of boilers, (II) available chemical effluent (salt water), and (III) available cooling water, are examined and compared in this research. As, required salt water or/and cooling water are much more than the available amounts in the power plant, scenario I and II are rejected. Based on obtained resulted from the scenario III, the cost of production is 0.8 $/m3 of fresh water, and the GOR of proposed HD desalination unit is 1.03. With consumption of less than 5% and 10% of the available steam and salt water in the power plant, respectively, more than 7.5 m3/day of fresh water can be produced by the proposed direct-contact HD desalination system.

Chemically enhanced oil recovery techniques have been considered efficient tertiary methods to improve the oil production from oil reservoirs regarding their compatibility with the reservoir characteristics. Moreover, gravity segregation and viscous fingering during carbon dioxide flooding would be the main problems of oil recovery techniques. In this paper, a hybrid chemical flooding that contained the subsequent flooding of surfactant–polymer​ (henceforth; SP) coupled with supercritical carbon dioxide was performed to enhance the oil recovery factor. The foaming agent that is used in this experiment is solely formed by CO2. It is concluded that SP-foam flooding had witnessed the highest blockage, which is caused to have the maximum cumulative oil recovery factor (about 78%) due to the more mobilization oil in low permeable pores and cracks. Furthermore, direct foam flooding has the second-highest oil recovery factor (nearly 70%), which is considered as the preferable techniques to SP-CO2 flooding (65%). On the contrary, SP-foam flooding has provided the highest pressure drop after the minimum miscible pressure circumstances, which is about 0.27 MPa at the end of the process.

This paper experimentally investigated influential thermodynamic reservoir characteristics such as pressure, temperature, soaking time, core stimulation, number of cycles, shale particle size, and carbon dioxide phase during the cycling carbon dioxide injection. The carbon dioxide supercritical phase has reached the maximum recovery factor of 40%. When carbon dioxide is in the supercritical phase, its density will become lower than the liquid phase due to the high pressure. Therefore, the oil recovery factor has been increased in micro and nanopores. It is concluded that more than 12 h of carbon dioxide soaking would not play a significant role in oil recovery enhancement. It was observed that each shale particle size distribution would be a proper representative for the carbon dioxide adsorption calculation. Therefore, by doing this, the required time to equilibrate pressure for carbon dioxide adsorption would be decreased by pulverizing the shale cores into micro and nanoparticles. In higher temperatures, carbon dioxide helps to retrograde vaporize hydrocarbon liquid as carbon dioxide provided a higher gas–oil ratio (GOR), higher value of condensate oil density. Thereby, due to increased carbon dioxide content, oil recovery has been increased, indicating that carbon dioxide would be properly soluble. Therefore, at 120 °C, the oil recovery factor has the highest value of 64%. At 3000 psi, the oil recovery factor has the highest value, and it has reached 60% after 14 cycles of carbon dioxide injection. It would be related to the more surface area of carbon dioxide with shale matrixes. Finally, temperature increase would reduce the carbon dioxide absorption, which has a reverse pattern with oil recovery factor increase by the temperature increase.

The regasification of liquefied natural gas provides considerable cold energy that would have practical potential in different industrial fields and makes a suitable option for integrating with cryogenic air separation systems that requires a significant amount of energy. In this research, two-column cryogenic air separation units are driven with solar photovoltaic panels to produce oxygen and nitrogen. The gaseous natural gas feeds a molten carbonate fuel cell (MCFC), producing electricity and heat. The heat is recovered by an absorption–compression refrigeration cycle (ACRC) to supply a high-intensity cooling load at −67 °C. The proposed scheme is designed to provide 1781 kmol/h oxygen, 8574 kmol/h nitrogen, 136 MW electrical power, and 13.09 MW cooling load. The thermal efficiency of the whole combined structure and the electrical efficiency of the fuel cell are 51.07% and 51.93%, respectively. The exergy analysis illustrates that the solar photovoltaic collectors and heat exchanges are the two most exergy destructive components compared to others. The exergy efficiency and irreversibility of the developed hybrid process are 52.77% and 160.5 MW, respectively. The effect of working temperatures has been studied on the performance of the molten carbonate fuel cell, including voltage, power density, and efficiency. The exergy and thermal efficiencies of the proposed system increase up to 56.18% and 55.05%, respectively with an increase of LNG molar flow rate from 892 to 992 kmol/h.

Increasing the performance of heat exchangers is one of industry’s most pressing challenges. Pulsating heat pipes (PHPs), as a novel technology with high-performance, are broadly used in solar distilled water and systems solar water heaters. In the present work, the impact of three nanofluids including zirconium dioxide (ZrO2), bismuth ferrite (BiFeO3)/ZrO2 (ZBF), and ZrO2/SiO2composites under concentrations of 0.25, 0.5, and 1.0 g/L was investigated on the PHPs performance. The thermal resistance of the base fluid and the produced nanofluids was compared under a constant filling ratio of 50% and different input powers to the evaporator. The obtained results revealed that the use of working fluid such as nanofluids increased the heat transfer of PHPs in comparison to the base fluid and reduced the thermal resistance. Among the nanofluids used, the concentration of 0.25 g/L of the prepared nanocomposites provided the best performance. The resistance of the PHPs at some fluxes was reduced by up to 40%. In general, from the point of view of materials engineering, the structure of compounds used in nanofluids should have low thermal resistance, high thermal conductivity, and low viscosity. From a chemical point of view, using metals and compounds with high thermal conductivity is essential due to significant electron exchange.

This paper presents reliability, availability, and maintainability (RAM) analysis framework for evaluating the performance of a circulation system of water (WCS) used in a coal-fired power plant (CFPP). The performance of WCS is evaluated using a reliability block diagram (RBD), fault tree analysis (FTA), and Markov birth–death probabilistic approach. In this work, the system under study consists of five subsystems connected in series and parallel configuration namely condensate extraction pump (CEP), low-pressure feed water heater (LPH), deaerator (DR), boiler feed pump (BFP), high-pressure feed water heater (HPH). The reliability block diagram (RBD) and fault tree approach (FTA) have been employed for the performance evaluation of WCS. The Markov probabilistic approach based simulation model is developed. The transition diagram of the proposed model represented several states with full working capacity, reduced capacity, and failed state. The ranking of critical equipment is decided on the basis of criticality level of equipment. The study results revealed that the boiler feed pump affects the system availability at most, while the failure of deaerator affects it least. The availability of the system is optimized using the particle swarm optimization method. The optimized availability parameter (TBF, TTR) based modified maintenance strategy is recommended to enhance the availability of the plant system. The optimized failure rate and repair rate parameters of the subsystem are used to suggest a suitable maintenance strategy for the water circulation system of the thermal power plant. The proposed RAM framework helps the decision-makers to plan the maintenance activity as per the criticality level of subsystems and allocate the resources accordingly.

In this investigation, a solar-driven multi-generation plant is developed and studied through exergy assessment. The developed integrated system is designed to provide power, cooling, freshwater, and hot water for an industrial complex. The designed layout consists of solar parabolic trough collectors as the main driver which can provide the driving temperature of 220 °C at its maximum output, a combination of Kalina cycle and ejector refrigeration to produce cooling load and power for the industrial complex, and multi-effect distillation unit to generate freshwater. Exergy assessment shows that collectors are the most destructive equipment in the designed layout. The exergy efficiency of the solar parabolic trough collectors reaches to 49.36%. The total exergy efficiency of the presented system achieves up to 25.92%. The designed system provides 32.27 kW of power, 156.3 kW of cooling, 4.907 m3/h of freshwater, and 1.449 m3/h of hot water at 61.4 °C. Additional assessments show that vapor generator pressure is a key factor on the output performance of the presented system. It has been shown that the total exergy efficiency of the system decreases by increasing the vapor generator pressure. The economic assessment illustrates that the investment return period and the prime cost of the product are 3.958 years and 1.773 US$/m3 freshwater, respectively.

Abstract This research is proposed to fully investigate the performance of a single‐effect water/lithium bromide absorption chiller driven by geothermal energy. Since absorption cycles are considered as low‐grade energy cycles, this innovative idea of rejecting fluid from a single‐flash geothermal power plant with low‐grade energy would serve as efficient, economical, and promising technology. In order to examine the feasibility of this approach, a residential building which is located in Sharjah, UAE, considered to evaluate its cooling capacity of 39 kW which is calculated using MATLAB software. Based on the obtained cooling load, modeling of the required water/lithium bromide single‐effect absorption chiller machine is implemented and discussed. A detailed performance analysis of the proposed model under different conditions is performed using Engineering Equation Solver software (EES). Based on the obtained results, the major factors in the design of the proposed system are the size of the heat exchangers and the input heat source temperature. The results are presented graphically to find out the geofluid temperature and mass flow and solution heat exchanger effectiveness effects on the chiller thermal performance. Moreover, the effects of the size of all components of the absorption chiller on the cooling load to meet the space heating are presented. The thermal efficiency of the single‐flash geothermal power plant is about 13% when the power plant is at production well temperature 250℃, separator pressure 0.24 MPa, and condenser pressure 7.5 kPa. The results show that the coefficient of performance (COP) reaches about 0.87 at solution heat exchanger effectiveness of 0.9, when the geofluid temperature is 120℃.

Abstract Background There has been an increasing resistance rate to tetracyclines, the first line treatment for cholera disease caused by V. cholera strains, worldwide. The aim of the present study was to determine the global status of resistance to this class of antibiotic among V. cholera isolates. Methods For the study, electronic databases were searched using the appropriate keywords including: ‘Vibrio’, ‘cholera’, ‘Vibrio cholerae’, ‘V. cholerae’, ‘resistance’, ‘antibiotic resistance’, ‘antibiotic susceptibility’, ‘antimicrobial resistance’, ‘antimicrobial susceptibility’, ‘tetracycline’, and ‘doxycycline’. Finally, after some exclusion, 52 studies from different countries were selected and included in the study and meta-analysis was performed on the collected data. Results The average resistance rate for serogroup O1 to tetracycline and doxycycline was 50% and 28%, respectively (95% CI). A high level of heterogeneity (I 2 > 50%, p-value 0.05). However, the Egger’s tests showed some evidence of publication bias in the studies conducted on serogroup O1. Conclusions The results of the present study show that the overall resistance to tetracyclines is relatively high and prevalent among V. cholerae isolates, throughout the world. This highlights the necessity of performing standard antimicrobial susceptibility testing prior to treatment choice along with monitoring and management of antibiotic resistance patterns of V. cholerae strains in order to reduce the emergence and propagation of antibiotic resistant strains as well as the failure of treatment.

Abstract Marine renewable energy has made significant progress in the last few decades. Even after making substantial progress, the cost of electricity produced by tidal turbines is high. Therefore, the current paper concentrated on reducing the cost of transportation and installation of the turbine by performing a model. Extreme Learning Machine and Support Vector Machines as well as Genetic Programming were applied to predict the performance of the turbine model by creating short‐term, multistep‐ahead prediction models to compute the performance of the H‐rotor vertical axis Folding Tidal turbine. The performance of the turbine was verified by a numerical study using the three‐dimensional approach for the viscous model with the unsteady flow. Statistical evaluation of the outcomes pointed out that advanced Extreme Learning Machine simulation made the assurance in formulating an innovative forecasting strategy for investigating the performances of the tidal turbine. This study shows that the application of the new procedure resulted in confident generality performance and learns faster than orthodox learning algorithms. In conclusion, the assessment indicated that the advanced Extreme Learning Machine simulation was capable as a promising alternative to existing numerical methods for computing the coefficient of performance for turbines.

The coronavirus disease 2019 (COVID-19) is an emerged infectious disease characterized by a severe pneumonia leading to death in some cases. Currently, no licensed vaccines, drugs, or biologics have been confirmed to be absolutely effective in prophylaxis or treatment of this novel infection. Therefore, the treatment of this highly contagious disease remains a global concern and emergency. The viral interference is a competition phenomenon by which a primary virus infecting a cell prohibits the infection of the same cell by another (secondary) virus. The phenomenon has recently been indicated to be exploited for antiviral strategies. This strategy, particularly when there is no efficient drug against a viral infection, is of high importance. Some researchers have studied the application of the phenomenon among different viruses. In this paper, I discussed the possibility of the application of interference phenomenon in prophylaxis of the disease.

Abstract Background The beneficial effects of polyphenols have been reported. This study aimed to investigate the effect of oral Ellagic acid (EA) supplement on insulin resistance (IR) and Fetuin-A and serum sirtuin1 (SIRT1) in type 2 diabetics. Methods In this double-blind, randomized clinical trial, 44 diabetic patients were selected. Patients were assigned to the intervention group (22 subjects) and placebo (22 subjects) and received a capsule containing 180 mg of EA per day or placebo for eight weeks, respectively. At the beginning and end of the study, anthropometric indices, fasting plasma glucose (FPG), plasma insulin level, IR, Fetuin-A, and SIRT1 were measured. Statistical analysis was performed using SPSS software. Results At the beginning and end of the study, there was no significant difference between the two groups regarding anthropometric indices (P > 0.05). At the end of the survey, EA supplementation significantly reduced FPG, insulin, IR, and Fetuin-A and increased SIRT1 levels compared with the placebo group (P 0.05). Conclusion EA with antioxidant properties plays an essential role in reducing the macrovascular and microvascular complications of diabetes by reducing inflammation and insulin resistance. Trial registration The protocol of this clinical trial is registered with the Iranian Registry of Clinical Trials ( http://www.IRCT.IR , identifier: IRCT20141025019669N13)

Heat and flow pattern of a vertical free jet impinging on a hot disk were numerically investigated. A cylinder with various thicknesses and materials exposed simultaneously to uniform heat flux on one side and a free impinging jet on the other side is simulated by ANSYS Fluent 19.3. For simulations, the thermal boundary condition on the hot surface might differ due to the nature of the heat flow. The Volume of Fluid (VOF) approach is used to model the free jet heat transfer and fluid dynamics with the presence of air, while only the energy equation is solved in the cylinder. Heatline equation is solved to reveal the heat flow direction and effects of different geometry conditions. The maximum heat flux of 2.5 MW/m2 was obtained at the edge of stagnation region for hot target made of copper, while the value was 1.5 MW/m2 when the material was combined with stainless steel. However, the general thermal and hydrodynamic features of the jet flow were not influenced. It means that hot object condition may only affect the balance between heat flux and temperature, and the ideal uniform heat flux on the impinging wall may not be achieved in any experimental conditions.

The turbulent convective thermal transfer in channel heat exchangers (CHEs) is studied numerically via the CFD (Computational Fluid Dynamics) method. Deflectors are inserted on the hot bottom walls of the heat channel to enhance the hydrothermal characteristics. Various shapes of in-line deflectors are considered, namely: rectangular (a/b = 0.00), cascaded rectangular-triangular (a/b = 0.25, 0.50, and 0.75), and triangular (a/b = 1.00) shapes. From the obtained results, the inclusion of in-line deflectors with a/b = 0.75 has given the most significant thermal enhancement factor, which was higher than that for a/b = 0.00, 0.25, 0.50, and 1.00 by about 5.36, 5.06, 67.27, and 3.88%, respectively. Also, the in-line cascaded deflector’ case (a/b = 0.75) shows an increase in the enhancement factor (η) from 4 to 15.44% over the cases of one deflector (corrugated, rectangular, triangular, trapezoidal, arc, (+), S, 45° V, 45° W, T, Γ, and ε-shaped) or two deflectors (staggered corrugated). This highlights the effectiveness of in-line cascaded rectangular-triangular deflectors with a/b = 0.75 in improving the performance of the proposed exchanger for the conditions adopted.

The appropriate maintenance strategy is essential for maintaining the thermal power plant highly reliable. The thermal power plant is a complex system that consists of various subsystems connected either in series or parallel configuration. The boiler–furnace (BF) system is one of the most critical subsystems of the thermal power plant. This paper presents availability based simulation modeling of the boiler–furnace system of thermal power plant with capacity (500MW). The Markov based simulation model of the system is developed for performance analysis. The differential equations are derived from a transition diagram representing various states with full working capacity, reduced capacity, and failed state. The normalizing condition is used for solving the differential equations. Furthermore, the performance of the system is analyzed for a possible combination of failure rate and repair rate, which revealed that failure of the boiler drum affects the system availability at most, and the failure of reheater affects the availability at least. Based on the criticality ranking, the maintenance priority has been provided for the system.The availability of the boiler–furnace system is optimized using particle swarm optimization method by varying the number of particles. The study results revealed that the maximum system availability level of 99.9845% is obtained. In addition, the optimized failure rate and repair rate parameters of the subsystem are used for suggesting an appropriate maintenance strategy for the boiler–furnace​ system of the plant. The finding of the study assisted the decision-makers in planning the maintenance activity as per the criticality level of subsystems for allocating the resources.

Abstract Nowadays, the low efficiency of solar energy power plant systems brings about uneconomical performance and high‐cost uncompetitive industries compared with the traditional fossil fuel ones. In order to overcome these kinds of issues, in this study, the performance of a solar tower coupled with a Rankine cycle is scrutinized using the first and second laws of thermodynamic. Moreover, a numerical code has been developed in the GNU Octave software environment to calculate the precise value for both energy and exergy losses of each component. Furthermore, the sensitivity analysis approach corresponds to the variation of several inner parameters such as direct normal irradiation (DNI), molten salt outlet temperature (MSOT), and the molten salt velocity (MSV), environmental parameters such as wind speed and ambient temperature have been performed. In addition, the overall losses are calculated by considering all possible forms of losses such as convection, conduction, reflection, and emission, and also, the portion of each source of these losses are determined. The obtained results indicate that the maximum exergy loss occurs in the central receiver system (CRS), while the major energy loss occurs in the turbine located in the power block. The sensitivity analysis shows that the rise of DNI significantly increases the exergy%energy efficiency of the cycle and also, the portion of loss related to emission heat transfer would be enhanced. Moreover, the variation of the MSV and MSOT illustrate influencing the performance of the cycle; consequently, the MSOT changes demonstrate a reverse relation with energy and direct relation with exergy efficiency. Accordingly, an optimum value of 650K is calculated for the MSOT as well as an optimum value of 2 m%s for the MSV. The environmental sensitivity analysis indicates that the enhancement of wind speed and ambient temperature has a negative impact on the net output of the cycle, which is not desirable.

Abstract In the present investigation, a solar parabolic trough concentrator (PTC) with a linear cavity was examined by using a developed numerical model. More specifically, a V‐shape cavity receiver was studied in this work as a new and alternative design. The use of a cavity in a PTC is a very promising idea because it leads to high efficiency and to low investment cost. Up today, the emphasis in the use of cavities is given in dish concentrators and so there is a need for investigation of cavities also in linear concentrators. Different dimensional and operational parameters of the PTC with a V‐shape cavity were considered. More specifically, the position, aperture area, and the tube diameter of the V‐shape cavity, solar irradiance, inlet temperature level, and mass flow rate were evaluated based on sensitivity analysis. The results revealed that the highest optical performance was attained when the cavity was placed at the PTC focal line. Moreover, it is found that there is an optimum cavity aperture area to determine the greatest thermal efficiency. For the optical errors of 5, 10, 15, 20, and 35 mrad, the optimum cavity aperture wide was calculated at 5, 5, 6, 7, and 8 cm, respectively, with the tracking error to be 0°. The highest thermal performance has found when the collector operates with low inlet temperature, high flow rate, high solar irradiation level, and small cavity tube diameter.

Abstract In this research, it is investigated to numerically evaluate the performance of a polymer electrolyte membrane fuel cell (PEMFC). The performance is investigated through the nonuniformity gradient loading at the catalyst layer (CL) of the considered PEMFC. Computational fluid dynamics is used to simulate a 2D domain in which a steady‐state laminar compressible flow in two‐phase for the PEMFC has been considered. In this case, a particular nonuniform variation inside the CL along the channel is assumed. The nonuniform gradient is created using a nonisothermal domain to predict the flooding effects on the performance of the PEMFC. The computational domain is considered as the cathode of PEMFC, which is divided into three regions: a gas channel, a gas diffusion layer, and a CL. The loading variation inside the catalyst is defined as a constant slope along the channel. In order to find the optimum slope, different slope angles are analyzed. The results point out that the nonuniform loading distribution of the catalyst (platinum) along the channel could improve the fuel cell performance up to 1.6% and 5% for power density and voltage generation, respectively. It is inferred that it is better to use more catalyst in the final section of the channel if the performance is the main concern.

Abstract Increasing greenhouse gas emissions and negative environmental consequences have raised worldwide attention to ecological issues. The development of carbon regulations (CRs) beside carbon capture and storage (CCS) systems is part of carbon mitigation policies (CMPs), which are following in recent years to control and manage carbon liberation. Along with environemtal policies, the utilization of renewable energy resources have been promoted significantly. However, the economic opportunities for renewable energy development considering CMPs have not addressed extensively. In this study, a stochastic mathematical programming model has been presented to minimize cost and downside risk (DSR) of the bioelectricity generation supply chain considering the pre‐ and postdisaster conditions. The role of several CMPs on the economic behavior of the system has been analyzed by investigating the potential uncertainties on material availability, material quality, and consumer demand. To consider disruption effects, the postdisaster stage has been classified into several substages including damage, recovery, and back to the sustainability stages. Mississippi State after the Katrina Hurricane is addressed as a case study to examine the performance of the proposed model. The results demonstrated that the occurrence of disruptive uncertainties creates 8,978,502 $, 8,864,335 $ and 8,884,055 $ as the DSR, under carbon tax policy (CTP), carbon offset policy (COP), and CCS, respectively. The effect of disruptive scenario 1 with a 15% reduction of resource has led to the greatest postdisaster supply chain costs in comparison with other scenarios. Although the financial analysis showed CTP has the greatest DSR after the occurrence of disaster, this policy has the most investment attractions, as well as COP, with the internal rate of return (IRR) of 9%. While implementing the CCS policy with the IRR of 2% creates 7% missed opportunity costs compared with other CMPs.

Abstract In order to attain an efficient path into the enhancement of the sustainable conservation and management of energy resources in the buildings and residential sections, efforts by all relevant institutions in the area of energy are essential and primitive. Hence, the development of the energy supply model in the building and the provision of fundamental solutions in this area is rudimentary. The key to any program related to this matter is to boost and extend energy efficiency and energy resource management. According to the global statistics and processed data, the residential sector accounts for 34 percent of the total energy consumption in Iran, which is the highest energy consumption compared to all existing sectors; therefore, immeasurable research has been done on optimizing energy usage in the building sector. One of the most efficient energy optimization methods can be achieved by using energy storage materials in the outer walls of the buildings. In this project, a research‐based residential building is considered as a case to investigate for energy optimization. In the first stage, the building is simulated and the energy consumption of the building is measured. Afterward, with actual measurements, real consumption is approximated and compared with the results of the software. After verifying the software data, the insulation is simulated in the software and the outcomes of using this insulator are investigated to reduce energy consumption. Energy storage materials are considered as a type of phase‐change material. These materials have the same characteristics which is having a different melting point and, by capturing and losing heat at design temperatures, they can help maintain energy inside the building that is how they can be considered as an insulator. Within the appropriate software which is Design‐Builder, miscellaneous types of these materials are available with various features. The final results point out that the use of this material saves up to 30% of the heating energy and about 8% in the cooling load of the building.

Abstract Recently, energy‐related CO2 emissions are considered as one of the most crucial issues and are promptly augmented due to further urbanization. In this paper, in order to model and calculate yearly CO2 emission, an artificial neural network is used. For the first time, the IWO‐SVM method has been applied in modeling energy‐related CO2 emissions. In this regard, consumption of different energy sources such as renewable energy, natural gas, coal, and oil, and GDP of the G8 countries in various years (from 1990 to 2016) are regarded as input in the present study. For the aim of evaluating the exact ability of the SVM and SVM‐IWO models, the performance of these models in three different modes is carried out on the basis of the number of data in the test and train sections. For this purpose, implementations are split into three categories (a = 80% of the data for the train section and 20% for the test section; b = 70% of the data for the train section and 30% for the test section; and c = 60% of the data for the train section and 40% for the test section). Furthermore, five scenarios were selected on the basis of the number of input parameters and input parameters for achieving the best model. As indicated in the results in all scenarios, the correlation of the model with the hybrid invasive weed algorithm based on SVM is more favorable than that in the support vector machine model, due to better training of the SVM‐IWO model than the SVM model. Moreover, the technological orientations of the G8 countries to mitigate CO2 emissions are determined through patent analysis. While the patents have essential information, investigating the published patent by a country could be helpful for determination of technological orientations. Hence, all published patents by these countries are extracted and deeply analyzed. In the next step, to find out main technological approaches, all patents and their intents have been studied. Eventually, the technological life cycles and trends of each main technology are drawn.

Agriculture and energy are inextricably connected; many energy systems can be driven by biomass supplied from agricultural waste products. In this study, a combined biomass/natural gas fed multi-generation system, prodcuing cooling, heating, and power is investigated from exergetic and thermo-economic standpoints. The system consists of four susbsystems, encompassing a gasification cycle, a gas cycle, a Rankine steam cycle, and a double effect absorption refrigeration cycle. To increase the lower heating value of the fuel injected into the combustion chamber, natural gas is mixed with syngas. Also, to exploit the exhaust gas from the stack of the gas turbine, the flue gas is divided into two streams by a spliter,providing the required heat for the Rankine steam and absorption refrigeration cycles. The effects of parameters such as the gas turbine inlet temperature , combustion chamber inlet pressure, the amount of natural gas mixed with syngas, and split ratio of the exhaust gas from the gas turbine on the thermodynamic and thermo-economic outputs are studied. The results show that the gas cycle with 61% and the double-effect absorption refrigeration cycle with 6% exergy destruction rates have the largest and lowest shares of the total exergy destruction rate, respectively. By changing the mixing ratio of the natural gas injected into the cycle from 0.5 to 1, the system's net work is seen to increase by 90.77%, while the modified ecological coefficient of the system performance boosts by 9.49%. In addition, such a change leads to 53.45% increase in the net present value of the total cost over the defined economic life, and also an increase of 90.25% in the net present value of the total output of the cycle equivalent to electricity over the economic life. Moreover, it brings about 19.36% decrease in the system's levelized cost of energy.

A fabric air dispersion system (FADS) is a type of flexible air supply system that integrates air transmission and distribution. This innovative system has the potential to address common issues such as uneven air supply and surface condensation, which are often associated with traditional ventilation systems. Existing numerical simulation studies on fiber ducts have encountered problems with mesh generation and simulation accuracy. This work develops a simulation method based on the equivalent discounting method to overcome these challenges. The proposed method is utilized to investigate the flow and heat transfer characteristics inside fiber ducts while also examining the effects of various shapes and opening configurations. The findings indicate that the temperature rise inside the duct is positively correlated with flow rate, with higher temperatures resulting from faster flow speeds. The temperature rise of FADS with four rows of openings increased by 0.4 k compared to other opening methods. Additionally, the study shows that increasing the number of rows of openings in the fiber duct leads to a faster decay of flow velocity and a higher temperature rise. At the same time, increasing the number of openings in the duct slightly reduces flow velocity while slightly increasing the temperature rise. The presence of more fiber duct elbows leads to greater local resistance, which accelerates the decay of the flow velocity and increases the temperature rise. Compared to the “1”-shaped FADS, the temperature rises of the “L”-shaped and “U”-shaped systems have increased by 0.9 k and 2.9 k, respectively.

Although various investigations of Atkinson cycle have been carried out, distinct output power and thermal efficiencies of the engine have been achieved. In this regard, thermal efficiency, Ecological Coefficient of Performance (ECOP), and Ecological function (ECF) are optimized with the help of NSGA-II method and thermodynamic study. The Pareto optimal frontier which provides an ultimate optimum solution is chosen utilizing various decision-making approaches, containing fuzzy Bellman-Zadeh, LINMAP, and TOPSIS. With the help of the results, interpreting the performances of Atkinson cycles and their optimization is enhanced. Error analysis has also been performed for verification of optimization and determining the deviation in the study.

In this study, machine learning methods of artificial neural networks (ANNs), least squares support vector machines (LSSVM), and neuro-fuzzy are used for advancing prediction models for thermal performance of a photovoltaic-thermal solar collector (PV/T). In the proposed models, the inlet temperature, flow rate, heat, solar radiation, and the sun heat have been considered as the input variables. Data set has been extracted through experimental measurements from a novel solar collector system. Different analyses are performed to examine the credibility of the introduced models and evaluate their performances. The proposed LSSVM model outperformed the ANFIS and ANNs models. LSSVM model is reported suitable when the laboratory measurements are costly and time-consuming, or achieving such values requires sophisticated interpretations.