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Essential oils of sweet lime peel, a waste by-product in the juice industry, were extracted using the vacuum assisted solvent free microwave extraction (VASFME) method. The effects of microwave output power (500–1000 W) and extraction time (20–30 min) on the essential oils yield and antimicrobial property were investigated. Optimal conditions were observed at 797.844 W microwave output power and 30 min extraction time. The essential oils yield and antimicrobial property under these conditions were 0.792 ± 0.03% and 18.25 ± 1.45 mm, respectively, which agrees with the predicted values of 0.757% and 16.50 mm. The essential oils were extracted at optimized conditions and analyzed through GCMS for compound identification. A total of 49 compounds were identified, with limonene content (43.47%) being the highest among all sweet lime peel oil compounds. Moreover, the sweet lime peels were subjected to ultrasound pre-treatment before microwave extraction. The ultrasound pre-treatment helped to increase the essential oils yield from 0.84 to 1.06% as the treatment time increased from 30 to 90 min. The increase in yield was 37.66% more compared to VASFME at 90 min treatment time.

Quick‐cooling heat exchangers are used for a wide range of industrial applications. This study is aimed at employing the wavy surfaces of the vortex generators to reduce pressure drops and enhance heat transfer performance. The turbulent conditions for mixture (water and air) flow with Re w = 3500–5000. The current numerical results are supported by experimental data from earlier literature. Subsequently, the impact of the working fluid flow rate on the parameters ( N u / N u o ), ( f / f o ) and thermohydraulic performance (THP) is investigated for both water flow and mixture flow (water and air) in a downward configuration at a 15° angle of attack in an oval tube bank heat exchanger. Also, this study investigated the performance of wavy VGs and oval and circular tubes, as well as downward and forward configurations, across different angles of attack (15°, 20° and 25°) in the mixture flow (water and air) by using Ansys Workbench 19.0 and SolidWorks 2018. The design of wavy VGs achieves optimal performance at an angle of attack ( α = 15 ° ) for circular tube banks within a mixture flow, characterised by both transition and turbulent zones.

Even though Photovoltaic technology is considered to be among the most convenient sources of electricity production, surface heat accumulation has consistently reduced its conversion efficiency. Therefore, many cooling strategies have been proposed, among which the Reversed Circular Flow Jet Impingement RCFJI is the most recent. This study seeks to address challenges associated with RCFJI, such as low turbulence generation and a high friction penalty, by developing a new design featuring Swirling Reversed Circular Flow Jet Impingement. The study was performed employing a solar simulator under air mass flow rates of (0.01–0.13) kg/s and an irradiance of (500–900) W/m 2 . The principal results showed that mass flow rate positively influences the efficiency of the proposed prototype, whereas solar irradiance has the opposite effect. The new design enhanced electrical energy efficiency by 12.42%, thermal energy efficiency by 4.33%, electrical exergy efficiency by 11.46%, and thermal exergy efficiency by 4.81%. Power production increased by 22.00% compared to a bare PV module. These data provide evidence that the proposed study design can better manage the thermal challenges of PV modules than PV alone or standard RCFJI.

In recent times, there has been increasing interest to address climate change by implementing renewable energy to enhance the energy sector as soon as possible. However, solar radiation turns into heat reducing the photovoltaic (PV) panel efficiency. The waste heat from PV panels can be utilized by thermoelectric (TE) to convert into electricity and enhance PV panel efficiency. In this study, the 3D CFD and thermal-electric numerical model was developed for thermal and electrical analysis of different heat sink designs and materials for a thermoelectric generator (TEG) to be used in a (PV) system. Heat sink was installed on the cold side of the Photovoltaic-Thermoelectric (PVTE) system to dissipate the heat from the PV panels, where varying flow inlets and convection coefficient parameters for dissipating the heat on the cold side of the PVTE system were investigated. The simulated TEG power generation with different heat sink designs, heat sink materials, convection coefficients (h) and flow inlets (v) were compared. The results showed that the TEG with pin fin heat sink design (H3) made from aluminium (Al) generated the highest power generations than the other designs. The results also showed the power generation significantly increases until saturation point around 2.01 m s − 1 for the flow inlet and also increases when the convection coefficient increases above 20 (W/m 2 ) °C.

Atrium spaces are widely applied in university buildings. However, achieving effective energy reduction while maintaining adequate daylighting and indoor comfort remains a major challenge at the early design stage. This study identifies key building form design variables significantly influencing atrium daylighting, energy use, and thermal comfort, including building orientation, atrium width-to-depth ratio, atrium aspect ratio, atrium bottom area ratio, and skylight–roof ratio. A multi-objective optimization (MOO) framework is proposed to balance daylight performance, energy consumption, and thermal comfort under fixed envelope parameters. Using typical single- and double-atrium teaching buildings in cold regions as case studies, this research adopts Useful Daylight Illuminance (UDI), Energy Use Intensity (EUI), and Discomfort Time Percentage (DTP) as key indicators to evaluate the interactions between design parameters and building performance. Based on the Pareto-optimal results for the studied prototypes, a south-by-west orientation, moderately slender atrium proportions, relatively compact atrium bottom areas, and medium skylight–roof ratios together yield a balanced performance. Compared with the reference to the initial solution, the optimized solutions reduce EUI by up to 5.66% while also improving UDI and DTP. These results are intended as quantitative references and optimization for early-stage geometric forms design of atrium teaching buildings in cold regions.

In the past few decades, there have been remarkable advances in our knowledge of gold nanoparticles (AuNPs) and synthesizing methods. AuNPs have become increasingly important in biomedical and industrial applications. As a newly implemented method, AuNPs are being used in nanopackaging industries for their therapeutic and antibacterial characteristics as well as their inert and nontoxic nature. As with other NPs, AuNPs have privileges and disadvantages when utilized in the food sector, yet a significant body of research has shown that, due to the specific nontoxic characteristics, AuNPs could be used to address other NP flaws. In this mini review, we present synthesizing methods, food industry applications, and mechanisms of action of gold nanoparticles. Regarding the investigations, gold nanoparticles can play a major role to reduce microbial load in foodstuff and therefore can be implemented in food packaging as an effective approach.

Plants employ various defence strategies to ameliorate the effects of heavy metal exposures, leading to re-establishment of metal homeostasis. One of the strategies includes the biosynthesis of main heavy metal detoxifying peptides phytochelatins (PCs) by phytochelatin synthase (PCS). In the present study, 14 PCS homologues were identified in the genomes of 10 selected plants. The size of these PCSs was 452-545 amino acid residues, with characteristic phytochelatin and phytochelatin_C domains. The N-terminal site of the proteins is highly conserved, whereas the C-terminal site is less conserved. Further, the present study also identified fully conserved Cys residues involved in heavy metal binding reported earlier. In addition, other preserved cysteines, with minor substitutions Cys(C)→Ser(S) or Tyr(Y) or Trp(W), were also identified in the PCS sequences that might be associated with metal binding. The reported catalytic triad residues from Arabidopsis, Cys56, His162 and Asp180, are all conserved at the respective sites of PCSs. A clear monocot/dicot separation was revealed by phylogenetic analysis and was further corroborated by the exon-intron organisations of the PCS genes. Moreover, gene ontology terms, co-expression network, cis-regulatory motif and miRNA analyses indicated that the complex as well as dynamic regulation of PCSs has significant involvement in different metabolic pathways associated with signalling, defence, stress and phytohormone, in addition to metal detoxification. Moreover, variations in protein structure are suggested to confer the functional divergence in PCS proteins.

Heat convection plays an important role in many industries, equipment, and human lives, and heat exchangers emerge as fundamental devices for controlling this crucial orientation. The primary objective of this work was to assess the effect of single‐ and two‐phase flows associated with wavy winglets on heat exchanger performance. Two‐phase flows as the working fluid with wavy winglets are used in the oval tube bank heat exchanger (HE). The Reynolds number area (3639–4813) is investigated in this experimental work. Wavy winglets at an attack angle of 15° have been shown to affect heat transfer rate through comparisons between the experimental results and various water‐air mixture flow rates ( Q w  = 15, 17.5, and 20 Lpm) ( Q a  = 8.33, 16.67, and 25 Lpm). A Nusselt number (Nu) is increased by 64.5%, and the friction factor ( f ) is decreased by 12.6% in water flow; the Nu is increased by 15.5%, and f remains almost constant in water‐air mixture flow at moderate turbulent flow. It can be noted that the Nu and the performance parameter ( j / f ) are directly proportional to the velocity of flow at moderate turbulent flow with any increase in turbulent flow, and the Nu and j / f are inversely proportional to the velocity of flow. Many parameters have been studied experimentally to establish their impact on performance parameters.

This paper investigates double-pass solar air thermal collectors with lava rock as the porous media. The addition of lava rock serves as short-term sensible thermal storage for a solar drying system. It also enhances the convective heat transfer rate to the airflow due to an increased heat transfer area and increased turbulence in the air channel. A mathematical model was developed based on energy balance equations and was numerically solved in MATLAB. The collector’s thermal performance was studied at various levels of solar intensity and at different wind speeds for different design parameters: collector size, air mass flow rate, and lava rock volume. From the study, the optimum efficiencies that were obtained in the range between the intensities of 500 W/m2 and 800 W/m2 were 62% to 64%, respectively, with an optimum flow rate of 0.035 kg/s. The optimum porosity of about 89% was selected for the collector by considering the pressure drop and thermal efficiency. An optimal temperature output range between 41.7 °C and 48.3 °C could be achieved and was suitable for agricultural and food drying applications. Meanwhile, compared to conventional DPSAHs, the average percentage increase in the output temperature of the DPSAH with lava rock was found to be higher by 17.5%.

Enhancing heat transfer in compact thermal systems remains a key engineering challenge, where internal geometry plays a decisive role in disrupting flow, increasing surface exposure, and boosting convective efficiency. In this study, a novel star-core fin insert was developed, featuring angularly spaced radial fins mounted on a central rod to improve the thermal-hydraulic performance factor (THPF). The design was optimized using a hybrid approach that combined the Taguchi method with Computational Fluid Dynamics (CFD) simulations, enabling systematic evaluation of five geometric parameters: fin diameter, number of fin edges, number of fins per rod, fin thickness, and angular offset. These parameters were varied concurrently to capture interaction effects and identify the most effective configuration. The optimal configuration (Case 31) achieved a THPF of 1.75, representing a 75% improvement over the smooth pipe baseline, with a fin diameter of 14.5 mm, five edges, four fins per rod, a thickness of 3 mm, and a 0° angular offset. A physical prototype of the absorber tube was fabricated and tested experimentally, showing strong agreement with numerical predictions (correlation = 95.5%, RMSE = 4.5%). These findings demonstrate that the integrated optimization framework is reliable and effective, improving heat transfer performance while maintaining acceptable pressure losses. The proposed passive design offers a scalable and energy-efficient solution for next generation compact heat exchangers.