Temporal and dosage impact of magnesium oxide nanoparticles on grass carp: unveiling oxidative stress, DNA damage, and antioxidant suppression.

Magnesium oxide nanoparticles (MgO NPs) have gained significant importance in biomedicine and variety of nanotechnology-based materials used in the agriculture and biomedical industries. However, the release of different nanowastes in the water ecosystem becomes a serious concern. Therefore, this study was executed to evaluate the toxic impacts of MgO NPs on grass carp. A total of 60 grass carp were randomly divided in three groups (G0, G1, and G2). Fish reared in group G0 were kept as control while fish of groups G1 and G2 were exposed to 0.5 mg/L and 0.7 mg/L MgO NPs, respectively, mixed in water for 21 days. The 96h median lethal concentration (LC50) of MgO NPs was found to be 4.5 mg/L. Evaluation of oxidative stress biomarkers, antioxidant enzymes, DNA damage in different visceral organs and the presence of micronuclei in erythrocytes were determined on days 7, 14, and 21 of the trial. Results revealed dose- and time-dependent significantly increased values of reactive oxygen species, lipid peroxidation product, DNA damage in multiple visceral organs and formation of micronuclei in the erythrocytes of treated fish (0.7 mg/L). The results on antioxidant profile exhibited significantly lower amounts of total proteins, catalase, superoxide dismutase, and peroxidase in visceral organs of the fish exposed to MgO NPs (0.5 and 0.7 mg/L) at day 21 of trial compared to control group. In conclusion, it has been recorded that MgO NPs severely influence the normal physiological functions of the grass carp even at low doses.

Thermal performance of dual flow slotted fin mini channel heat sink using Al2O3-H2O and TiO2-H2O: a numerical and experimental approach.

To overcome the extensive heat generation inside the microprocessors nanofluids have gained importance because of their better thermophysical properties as compared with air and water. This work proposes a two-pronged strategy for thermal performance enhancement of mini channel heat sinks. Firstly, a novel dual flow slotted fin mini channel heat sink flow configuration is proposed. Secondly, a detailed numerical investigation is performed to assess heat transfer enhancement property of Al2O3-H2O and TiO2-H2O nanofluids. Considering the first step, fin spacing, number of slots, slot thickness and slot angle are investigated in detail yielding to the selection of best structural parameters. Two slots per fin of 0.5 mm thickness at an angle of 45° is selected because it provides better thermal performance as compared with water. Further, numerical assessment of nano fluid behavior was carried out at volumetric concentrations of 0.005% and 0.01%. For the case of novel dual flow slotted fin mini channel heat sink, maximum numerical and experimental advantages in all targeted system properties is observed for Al2O3-H2O nano fluid at volumetric concentration of 0.01%, as compared with water. Al2O3-H2O nano fluid provides better thermal performance both numerically and experimentally as compared with TiO2-H2O nanofluids. Increment in the pressure drop is noted with increasing volumetric concentrations.

Enhanced heat transfer characteristics of the mini hexagonal tube heat sink using hybrid nanofluids.

The thermal performance of different hybrid nanofluids on the mini hexagonal tube heat sink has been investigated experimentally. Al2O3/SiO2-DIW, Al2O3/CuO-DIW, and CuO/SiO2-DIW nanofluids have been used as the working fluids. The aggregate of 0.01 volume fraction of Al2O3, CuO, and SiO2nanoparticles for hybridizing ratios (80:20) has been considered to prepare deionized water-based hybrid nanofluids. The thermal performance of three different hybrid nanofluids inside the mini hexagonal tube heat sink has been assessed. The varying volumetric flow rates of 15-50 lph have been maintained on the hexagonal tube side and 50 lph on the mini passage side. Herein, the proposed hexagonal-shaped heat sink provides a larger heat contact surface to exchange the heat between the hybrid nanofluids and hot DIW. It is divulged that the increase in the volume flow rate of nanofluids promotes the higher Brownian motion, leading to an increase in convective heat transfer. Amongst three hybrid nanofluids, CuO/SiO2-DIW nanofluids have revealed a slight increase in pumping power while increasing the volume flow rate. From the experimental results, it is shown that the heat transfer coefficient, effectiveness, and Nusselt number have been improved by 54.5%, 42%, and 28.4%, respectively, for Al2O3/CuO-DIW nanofluids. Thus, Al2O3/CuO-DIW nanofluid can be deemed to be an efficient working fluid for the miniature heat sinks to accelerate the heat transfer rates.

Disinfection of corona virus in histopathology laboratories.

Severe acute respiratory syndrome (SARS CoV-2/COVID-19) is a highly contagious and deadly disease caused by a virus belonging to the coronaviridae family. Researchers working in histopathology laboratories, dealing with morbid samples, are particularly vulnerable to infection unless they have very strong immunity. Hence, a proper precautionary protocol is required for the safety of the laboratory staff. The current review highlights the biological and physical agents that can be used to inactivate the virus and disinfect the surrounding environment in the laboratory.

Effect of foliar applied triacontanol on wheat (Triticum aestivum L.) under arsenic stress: a study of changes in growth, yield and photosynthetic characteristics.

In this study, changes in growth, yield and photosynthetic characteristics were assessed by foliar application of triacontanol (TRIA) in wheat (Triticum aestivum L.) varieties Anaj-2017, Ujala-2016 and AARI-2011 under arsenic (As) stress. Seeds of all three wheat varieties were sown in sand filled plastic pots. The experiment was conducted in a completely randomized design (CRD) with three replicates. All the plants were irrigated with full strength Hoagland's nutrient solution till the termination of experiment. Plants were applied with three levels of sodium arsenite (NaAsO2) i.e. 0 ppm, 50 ppm and 100 ppm and two levels of foliar treatment of triacontanol i.e. control (no spray), and TRIA 1 µM applied. After 16 week of germination, data of all photosynthetic characteristics was collected, while yield was taken at maturity. Arsenic (50 ppm and 100 ppm) stress exerted significantly adverse effects on various growth and photosynthetic parameters i.e. shoot fresh and dry weights, total leaf area per plant, total grain yield per plant, 100 grain weight, number of seeds per plant, chlorophyll (chl.) pigments, chl. a, b chl. a/b ratio, flavonoids, anthocyanin contents, rate of photosynthesis (A), transpiration rate (E), internal CO2 concentration (C i), water use efficiency (A/E), and stomatal conductance (g s). Foliar application of TRIA significantly increased growth and yield attributes, chlorophyll b, internal CO2 concentration, stomatal conductance, rate of photosynthesis, flavonoids and anthocyanin contents in all wheat varieties. Moreover, the results also indicated that 1 µM TRIA proved to be effective in reducing the adverse effects of arsenic stress on all three wheat varieties. Of three wheat varieties, AARI-2011 is more sensitive to arsenic stress and Anaj-2017 proved to be more tolerant against arsenic stress. However, foliar application of TRIA proves to be more effective for var. AARI-2011.

Bacterial, PCR and clinico-pathological diagnosis of naturally occurring pneumonic pasturellosis (mannheimiosis) during subtropical climate in sheep.

Mannheimia haemolytica is causative agent of pneumonic pasteurellosis (mannheimiosis) that causes huge economic losses to livestock farmers. We investigated the microbial and clinico-pathological patterns associated with ovine pneumonic pasturellosis during an outbreak. Prior to death, infected sheep revealed clinical signs including dyspnoea, salivation, pyrexia and mucopurulent nasal discharge. Mortality was significantly (p < 0.05) high in young sheep as compared to adults. Necropsy findings revealed presence of froth in trachea, congestion and consolidation of lungs, pulmonary edema, severe pleural adhesions, pericarditis, hemorrhages on mucosa of jejunum and kidneys. Histopathological examination revealed circumscribed and centrally calcified necrotic areas punctuated with chronic inflammatory cells and interstitial pneumonia. Moreover, bronchial epithelial hyperplasia, edema, congestion, mononuclear cell infiltration, thick interlobular septae and peri-vascular cuffing were the striking changes in lungs. Furthermore, lungs showed severe fibrin depositions along with abundant amount of fibrin meshwork on pleura infiltrated with chronic inflammatory cells. Histologically, liver, kidneys and lymph nodes showed degenerative changes. Mannheimia haemolytica and Pasteurella multocida were differentially identified on the basis of culture characteristics and biochemical tests. M. haemolytica was further confirmed by using polymerase chain reaction. From the findings of current study, it is concluded that M. haemolytica is a major respiratory threat in small ruminants that causes severe pneumonic changes in infected animals.

Patho-bacteriological investigation of an outbreak of Mycoplasma bovis infection in calves - Emerging stealth assault.

Mycoplasma bovis (M. bovis) is an important bacterium, causing severe respiratory infection, and arthritis in dairy animals worldwide. This study is based on 50 suckling calves among which 15 showed respiratory distress, lameness and swollen joints and died later. M. bovis was isolated and identified from all dead (n = 15) and live (17.14%; 06 out of 35) calves on the basis of bacteriological examination. In morbid calves, the carpus and stifle joints were severely affected, while necropsy revealed multiple well-circumscribed calcified abscesses and caseous exudates in cranio-ventral and diaphragmatic lobes of lungs. Suppurative polyarthritis, fibrino-suppurative, teno-synovitis and otitis media were the common and striking lesion observed at postmortem examination. Histopathological examination revealed broncho-interstitial pneumonia and necrotic fibrino-purulent broncho-pneumonia in lungs. Similarly, synovial membranes and joints revealed presence of multiple foci of liquefactive necrosis surrounded by lymphocytes, plasma cells, macrophages and peripheral fibroplasia. In the bacteriological investigations, the characteristic fried egg colonies of M. bovis further confirmed this infection in all suspected cases. In conclusion, the current clinico-histo-pathological features are the depictive picture, and is the first report of M. bovis infection in calves in Pakistan.

Thermal performance enhancement of lauric acid using nanomaterials as composite phase change material.

In the present work, lauric acid was taken as a phase change material (PCM), and different nanoparticles (NPs) such as SiO2, TiO2, CuO, and ZnO were taken as the supporting materials. CuO NPs were prepared through the co-precipitation technique; SiO2, TiO2, and ZnO NPs were synthesized via the sol-gel technique. These NPs with different weight fractions were dispersed into molten lauric acid, individually. The variations in thermal properties (phase change temperature and latent heat for solid and liquid) of the prepared composite PCMs due to the dispersion of NPs were observed by DSC analyses. An increase in thermal conductivity of the composite PCMs was observed with the increasing weight fraction of NPs. In order to ascertain the long-term utility, a thermal reliability test was conducted on the composite PCMs with repeated heating and cooling cycles. Also, the specific heats of the pure PCM and the composite PCMs were determined as a function of temperature. Further, the experimental investigation was performed on the pure PCM and the prepared composite PCMs to assess their phase change behavior, and the test results clearly proved that the time required for the complete melting and freezing process of the composite PCMs was less when compared to pure PCM. By considering the above facts, the newly prepared composite PCMs can be recommended as a potential candidate for low-temperature solar heating applications.

Effectiveness of cephalosporins in hydrolysis and inhibition of Staphylococcus aureus and Escherichia coli biofilms.

IMPORTANCE: Staphylococcus aureus and Escherichia coli contribute to global health challenges by forming biofilms, a key virulence element implicated in the pathogenesis of several infections. OBJECTIVE: The study examined the efficacy of various generations of cephalosporins against biofilms developed by pathogenic S. aureus and E. coli. METHODS: The development of biofilms by both bacteria was assessed using petri-plate and microplate methods. Biofilm hydrolysis and inhibition were tested using first to fourth generations of cephalosporins, and the effects were analyzed by crystal violet staining and phase contrast microscopy. RESULTS: Both bacterial strains exhibited well-developed biofilms in petri-plate and microplate assays. Cefradine (first generation) showed 76.78% hydrolysis of S. aureus biofilm, while significant hydrolysis (59.86%) of E. coli biofilm was observed by cefipime (fourth generation). Similarly, cefuroxime, cefadroxil, cefepime, and cefradine caused 78.8%, 71.63%, 70.63%, and 70.51% inhibition of the S. aureus biofilms, respectively. In the case of E. coli, maximum biofilm inhibition (66.47%) was again shown by cefepime. All generations of cephalosporins were more effective against S. aureus than E. coli, which was confirmed by phase contrast microscopy. CONCLUSIONS AND RELEVANCE: Cephalosporins exhibit dual capabilities of hydrolyzing and inhibiting S. aureus and E. coli biofilms. First-generation cephalosporins exhibited the highest inhibitory activity against S. aureus, while the third and fourth generations significantly inhibited E. coli biofilms. This study highlights the importance of tailored antibiotic strategies based on the biofilm characteristics of specific bacterial strains.

Effects of sub-lethal concentrations of lindane on histo-morphometric and physio-biochemical parameters of Labeo rohita.

Lindane is a broad-spectrum insecticide widely used on fruits, vegetables, crops, livestock and on animal premises to control the insects and pests. The extensive use of pesticides and their residues in the soil and water typically join the food chain and thus accumulate in the body tissues of human and animals causing severe health effects. The study was designed to determine the toxicity effects of sub-lethal concentrations of lindane on hemato-biochemical profile and histo-pathological changes in Rohu (Labeo rohita). A significant increase in the absolute (p<0.05) and relative (p<0.05) weights was observed along with severe histo-pathological alterations in liver, kidneys, gills, heart and brain at 30µg/L and 45µg/L concentration of lindane. A significant (p<0.05) decrease in RBCs count, PCV and Hb concentration while a significant (p<0.05) increased leukocytes were observed by 30µg/L and 45µg/L concentrations of lindane at 45 and 60 days of the experiment. Serum total protein and albumin were significantly (p<0.05) decreased while hepatic and renal enzymes were significantly (p<0.05) increased due to 30µg/L and 45µg/L concentrations of lindane at days-45 and 60 of experiment compared to control group. The observations of thin blood smear indicated significantly increased number of erythrocytes having nuclear abnormalities in the fish exposed at 30µg/L and 45µg/L concentrations of lindane. ROS and TBARS were found to be significantly increased while CAT, SOD, POD and GSH were significantly decreased with an increase in the concentration and exposure time of lindane. The results showed that lindane causes oxidative stress and severe hematological, serum biochemical and histo-pathological alterations in the fish even at sub-lethal concentrations.

Molecular identification of different toxinogenic strains of Clostridium perfringens and histo-pathological observations of camels died of per-acute entero-toxaemia.

Enterotoxaemia is a severe disease caused by Clostridium perfringens and render high mortality and huge economic losses in livestock. However, scanty information and only few cases are reported about the presence and patho-physiology of enterotoxaemia in camels. The bacterium induces per-acute death in animals due to rapid production of different lethal toxins. The necropsy of camels (per-acute = 15, acute = 3) was conducted at 18 outbreaks of enterotoxaemia in camels in the desert area of Bahawalpur region. At necropsy, the serosal surfaces of visceral organs in the abdominal, peritoneal and thoracic cavities were found to have petechiation with severe congestion. Moreover, both the cut-sections of different visceral organs and the histo-pathological analysis revealed the pathological lesions in heart, lungs, kidneys, spleen, small and large intestines. Grossly, the kidneys were severely congested, hyperemic, swollen and softer in consistency. Under the microscope, different sections of kidneys indicated that the convulated and straight tubules were studded with erythrocytes. In the intestines, there were stunting fusion of crypts and villi. Similarly, various histo-pathological ailments were also observed in the heart, lungs and spleen. At blood agar, the collected samples showed beta hemolytic colonies of C. perfringens that appeared as medium sized rods microscopically and stained positively on Gram staining. Multiplex PCR revealed C. perfringens type A (α and ß2 genes) and D (epsilon gene) and the deaths were found to be significantly higher due to C. perfringens type D compared to those by C. perfringens type A. Hence, it has been concluded that enterotoxaemia in camel affects multiple organs and becomes fatal, if occurred due to C. perfringens type D.

Recent Advances in the Applications of Green Synthesized Nanoparticle based Nanofluids for the Environmental Remediation.

With the ever-growing importance of green technology, the utilization of inorganic metal oxide nanoparticles and their nanofluids against microorganisms garnered more attention than organic metal oxides in recent years. Therefore, using safer, energy and cost-effective natural raw materials, stabilizing agents, and solvents are the fundamental considerations of the greener process. Due to their unique properties, larger surface area to volume ratio, higher stability and selective toxicity towards microbial pathogens, ZnO, TiO2 and silver nanoparticles are considered environmentally friendly and cost-effective antimicrobial agents. Furthermore, amine-based silica nanoparticles and carbon nanotubes are used for the carbon dioxide and hydrogen sulfide separation. The review mainly focuses on the green synthesis of the various nanoparticles to form nanofluids and their application in environmental remediation. In this light, the current paper briefly summarizes the preparation methods and the prospective environmental remediation applications of various nanofluids in the field of microorganisms controlling mechanisms, wastewater treatment methods and harmful gaseous removal methods.

Building Resilient communities: Techno-economic assessment of standalone off-grid PV powered net zero energy (NZE) villages.

The use of renewable energy resources for off-grid electricity production has gained more importance in recent decades for meeting the energy needs of remote areas, even with limited resources. This research aims to provide an optimized and cost-effective approach for generating electricity in rural areas. By using current methodology, a stand alone energy source of PV is designed for development of NZE village. Solar irradiance of the selected location is 6.16 kWh/m2/day while the estimated electric load data for whole village is 64.259 kWh. Electric load and solar irradiance of the loaction is used in the Hybrid Optimization Model for Electric Renewable (HOMER) to design and analyze the techno-economic feasibility of the stand alone PV system to meet the load requirements. The study obtained the total Net Present Cost (NPC) of $0.511 M and the Cost Of Electricity (COE) is 2.26$/unit through the HOMER analysis, which is further refined by performing sensitivity analysis using parameters such as PV panel price, battery price, solar irradiance, variations in electric load and discount rates. According to the results, system is feasibile by annual electricity production of 30,078 kWh with initial capital investment of $0.434 M. This analysis compared the system performance and showed that it is economically and technically viable to meet the complete electricity needs of the village with a payback period of 7.2 years. Research can be utilized for policy making and implementation of NZE approach in remote areas by the government.

Effect of Different Host Plants on Life Type Characteristics of Three Spider Mite Pests (Acari: Prostigmata: Tetranychidae).

The present study evaluated the host plant effect on life type characteristics of three important spider mite pest species, Tetranychus urticae Koch, Eutetranychus orientalis (Klein), and E. palmatus Attiah (Acari: Prostigmata: Tetranychidae), based on both field and laboratory observations. The polyphagous species, T. urticae with complicated web (CW-u) life type, occupying unstable habitats, showed variations in the sites for quiescence (SQ), sites for oviposition (SO), sites for defecation (SD), and webbing density (WD) on different annual/perennial host plants. The SQ, SO, and SD of T. urticae were observed either on the leaf, web threads, or trichomes. Tetranychus urticae constructed the lowest WD on tomato plants and the highest WD on maize/mulberry plants. Two spider mite species of the genus Eutetranychus Banks, the polyphagous E. orientalis and the oligophagous E. palmatus, inhabit stable host plants, depicted in the little web (LW-j) life types with persistency in all characteristics on different plants. It is concluded that polyphagous spider mites have restricted their life types, showing their high adaptability to utilize the resources of different host plants for survival with slight variation in some important life type characteristics.

Enhancement of combustion effect leading to improved performance and exhaust emissions of an SI engine with ferrous oxide and graphite nanoparticles.

The present study was conducted to investigate the effectiveness of new, less toxic, less harmful, and nonmetallic graphite (G) and metallic iron oxide (Fe2O3) nanofuel additives by analyzing experimentally their consequences on exhaust emissions and performance of an air cooled, single cylinder, 4-stroke gasoline engine. Fe2O3 and graphite nanoparticles at 40, 80, and 120 mg/l of gasoline concentrations were mixed with gasoline by means of a magnetic stirrer. Brake power (BP), brake-specific fuel consumption (BSFC), torque (T), brake thermal efficiency (BTE), nitrogen oxides (NOx), carbon monoxide (CO), hydrocarbons (HC), and carbon dioxide (CO2) emissions were the investigated parameters. Experimental results indicated that G-blends showed a higher rise in brake power, brake thermal efficiency and torque and a greater reduction in the brake-specific fuel consumption as compared to that of Fe2O3 fuel blends. Moreover, the G-blends produced less NOx and CO2 than Fe2O3 blends but produced more emissions of CO and HC than that of Fe2O3 blends. On average, G-blends produced 0.46%, 0.71%, and 1.71% more torque, power, and BTE and 2.43%, 1.87%, and 13.39% less brake-specific fuel consumption (BSFC), NOx, and CO2 than Fe2O3 blends, respectively. So, in terms of the eight parameters, four performance parameters (i.e., T, BP, BSFC, BTE), and four engine emission exhaust indicators (i.e., CO, NOx, HC, CO2), graphite nanoparticles showed more positive results for 6 parameters (T, BP, BSFC, BTE, NOx, CO2), while two parameters HC and CO showed negative results with graphite as compared to that of Fe2O3 nanoparticles. So, overall, we conclude that nanoparticles of graphite are more engine and environment friendly than that of iron oxide fuel additives.

Application of Nanofluids for Machining Processes: A Comprehensive Review.

According to the demand of the present world, as everything needs to be economically viable and environment-friendly, the same concept applies to machining operations such as drilling, milling, turning, and grinding. As these machining operations require different lubricants, nanofluids are used as lubricants according to the latest technology. This paper compares different nanofluids used in the same machining operations and studies their effects. The variation in the nanofluid is based on the type of the nanoparticle and base fluid used. These nanofluids improve the lubrication and cooling in the machining operations. They also aid in the improvement in the surface roughness, cutting forces, cutting temperature of the workpiece, and tool life in the overall process taking place. It is worth noting that nanofluids are more effective than simple lubricating agents. Even within the nanofluid, the hybrid type is the most dominating, and helps to obtain a maximum efficiency through certain machining processes.

Experimental Analysis of Nano-Enhanced Phase-Change Material with Different Configurations of Heat Sinks.

The demand for high-performance and compact electronic devices has been increasing day by day. Due to their compactness, excessive heat is generated, causing a decrease in efficiency and life. Thermal management of electronic components is crucial for maintaining excessive heat within the limit. This experimental research focuses on the combined effect of nano-enhanced phase-change material (NePCM) with different configurations of heat sinks for cooling electronic devices. Multi-walled carbon nanotubes (MWCNTs) are used as nanoparticles with concentrations of 3 wt% and 6 wt%, RT-42 as the phase-change material (PCM), and aluminum as the pin fin heat sink material. Different configurations of the heat sink, such as circular, square, and triangular pin fins, are used against the fixed volume fraction of the fins. It is found that the square configuration has the highest heat transfer with and without PCM. A maximum base temperature reduction of 24.01% was observed in square pin fins with RT-42 as PCM. At 6 wt% of NePCM, the maximum base temperature lessened by 25.83% in the case of a circular pin fin. It is concluded from the results that a circular pin fin with NePCM is effective for base temperature reduction, and all fin configurations with NePCM collectively reduce the heat sink base temperature.

Thermal and Tribological Properties Enhancement of PVE Lubricant Modified with SiO2 and TiO2 Nanoparticles Additive.

The addition of nanoparticles may have a positive or negative impact on the thermal and tribological properties of base lubricant. The objective of this paper is to investigate the effect of nanoparticle dispersion in lubricant base in relation to its application in refrigeration system compressors. An investigation of tribological and thermal properties of nanolubricants for rolling piston rotary systems was carried out through four-ball tribology tests and thermal conductivity measurements. Nanolubricants dispersed with SiO2 and TiO2 nanoparticles were tested at various concentrations and temperatures. The changes in thermal conductivity and coefficient of friction (COF) were analyzed while wear weight loss was also calculated from wear scar size. A regression model of thermal conductivity enhancement was proposed for both types of nanoparticles. Zeta potential results show that nanolubricants have excellent stability. The thermal conductivity increases by the increment of nanoparticle concentration but decreases by temperature. The R-square for the regression model is more than 0.9952 with an average deviation not more than 0.29%. The COF for SiO2/PVE nanolubricant at 0.003 vol.% reduced 15% from the baseline. The COF for nanolubricants exceeds the result for base lubricants when the concentration is more than the threshold value. The optimum concentration of SiO2 and TiO2 nanoparticles improved the thermal and tribological properties of PVE lubricant and may offer an advantage when applied to refrigeration systems.

Heat Transfer Enhancement in Parabolic through Solar Receiver: A Three-Dimensional Numerical Investigation.

Parabolic trough collectors (PTC) are one of the most established solar concentrating systems which have been used in a wide variety of applications. Enhancing their performance is critical to establish them as a viable technology. Internal obstacles are an intriguing way for improving the collector's performance. However, the usage of obstacles results in increasing pressure loss. The purpose of this research is to numerically explore the impact of introducing obstacles to the receiver tube of a parabolic trough collector on heat transmission in PTCs and its overall thermal performance. The first part analyzed the effects of geometrical parameters, orientation angle (α = 45°, 90° or 135°), and spacing of obstacles (P/D = 1, 2, or 3) on the fluid motion, heat transfer, and performance. Then, a non-uniform heat flow was applied to the absorber's outer surface. The effects of nanoparticles type, temperature profile, and heat transfer performance of three different nanofluids (Cu/thermal oil, Al2O3/thermal oil, andTiO2/thermal oil) were studied in the second part. The simulation results show that, the friction factor increased when P/D decreases, and that the absorber tube with obstacles discs (α = 90°) and P/D = 2 achieved the best thermal performance. Additionally, increasing the concentration of solid nanoparticles in thermal oil improves heat transmission, and the Cu nanofluid has the greatest Nusselt number.

Performance of Air-Conditioning System with Different Nanoparticle Composition Ratio of Hybrid Nanolubricant.

To reduce fuel consumption, the automotive air-conditioning (AAC) system's coefficient of performance (COP) needs to be improved. The use of a diverse selection of hybrid nanolubricant composition ratios is expected to improve the properties of single nanolubricants, resulting in improved AAC system performance. The goal of this study was to find the best combination of hybrid nanolubricants for the best performance of the AAC system. Al2O3-SiO2/PAG hybrid nanolubricants at 0.06% volume concentrations with various composition ratios (20:80, 40:60, 50:50, 60:40, and 80:20) were investigated. An initial refrigerant charge of up to 155 g and a compressor speed of up to 2100 rpm were used in the experiment. The cooling capacity, compressor work, and COP of the AAC system were measured to determine its efficiency. The COP enhancement and compressor work reduction were recorded up to 16.31% and 18.65% for the 60:40 composition ratio, respectively. The maximum cooling capacity up to 75.84% was recorded for the 80:20 ratio, followed by 60:40. The maximum COP value of 8.81 for 155 g of hybrid nanolubricants was obtained at 900 rpm with a 60:40 composition ratio. Therefore, for optimal performance in the AAC system, a 60:40 composition ratio of the Al2O3-SiO2/PAG nanolubricant combination is strongly recommended.