Temperature Rise Research Articles

Type I Hsp40s/DnaJs aggregates exhibit features reminiscent of amyloidogenic structures.

A rise in temperature triggers a structural change in the human Type I 40 kDa heat shock protein (Hsp40/DnaJ), known as DNAJA1. This change leads to a less compact structure, characterized by an increased presence of solvent-exposed hydrophobic patches and β-sheet-rich regions. This transformation is validated by circular dichroism, thioflavin T binding, and Bis-ANS assays. The formation of this β-sheet-rich conformation, which is amplified in the absence of zinc, leads to protein aggregation. This aggregation is induced not only by high temperatures but also by low ionic strength and high protein concentration. The aggregated conformation exhibits characteristics of an amyloidogenic structure, including a distinctive X-ray diffraction pattern, seeding competence (which stimulates the formation of amyloid-like aggregates), cytotoxicity, resistance to SDS, and fibril formation. Interestingly, the yeast Type I Ydj1 also tends to adopt a similar β-sheet-rich structure under comparable conditions, whereas Type II Hsp40s, whether human or from yeast, do not. Moreover, Ydj1 aggregates were found to be cytotoxic. Studies using DNAJA1- and Ydj1-deleted mutants suggest that the zinc-finger region plays a crucial role in amyloid formation. Our discovery of amyloid aggregation in a C-terminal deletion mutant of DNAJA1, which resembles a spliced homolog expressed in the testis, implies that Type I Hsp40 co-chaperones may generate amyloidogenic species in vivo.

Preparation and thermal properties of latent functional thermal fluid based on size-controllable phase change nanocapsules

Size-controllable 1-octadecanol@polystyrene phase change nanocapsules (NEPCMs) were prepared using the miniemulsion polymerization and dispersed in deionized water containing multi-walled carbon nanotubes to prepare a latent functional thermal fluid (LFTF). The results demonstrate that the NEPCMs exhibit a typical core-shell structure. The average particle size (55.28–143.8 nm) of the NEPCMs can be regulated by controlling the content of compound emulsifiers. The optimal phase change enthalpy has an excellent heat storage capacity of about 222.7 J/g, the encapsulation efficiency is up to 80.63 %, and the average particle size is about 88.3 nm. The heating/cooling cycles results show that NEPCMs have excellent cycle stability. LFTF containing 10 wt% NEPCMs was considered the optimal choice for its excellent photothermal conversion efficiency (up to 64.91 %), excellent dispersion stability (zeta potential 39.17 mV) and thermal storage capacity (peak specific heat capacity 5.72 J g−1 K−1). Under the influence of solar radiation, the temperature rise curve of LFTF exhibited a rapid initial warming rate followed by a plateau period of approximately 76 min upon reaching the melting point of the NEPCMs, whose photothermal conversion efficiency is roughly 2.18 times that of water. The experimental findings demonstrate the potential application of LFTF based on NEPCMs in the solar thermal industry.

Adsorption characteristics and applications of andesite in removing some pollutants from wastewater

Andesite was employed to effectively extract mercury(II) in an aqueous solution. After evaluating its characteristics, andesite was characterized by applying modern techniques such as BET and TGA methods. The study employed SEM and TEM measurements to analyze the variation in the surface shape and crystallinity of the metal due to adsorption. Using the EDX process, the chemical composition, weight, and atomic percentage of each element of andesite were determined. FTIR techniques were also used to confirm the TEM–EDX findings. Zeta potential was estimated. Cycles of regeneration and desorption have been examined. 99.03% was the highest uptake percentage. Adsorbent quantity (0.0025–0.05) g/L, contact time (5–60) min, pH (2–10), temperature (25–60) °C, and dose (0.0027, 0.0044, 0.0125, 0.0155, and 0.0399) mg/L all affect the amount of removal that increases with the increase in contact time, pH, dose, and temperature but drops as the metal ion concentration rises. The ideal values for contact time, pH, metal ion concentration, dose, and temperature were found to be, respectively, 30 min, 0.0155 mg/l, 0.02 g/l, and 40 °C. The calculation of thermodynamic parameters, including ΔH, ΔG, and ΔS, was imperative in establishing that the mechanism of heavy metal adsorption on andesite was endothermic, exhibiting a physical nature that escalated with temperature rise. The Freundlich adsorption equation's linear form is matched by the adsorption of mercury(II) on andesite; constant n was 1.85, 1.06, 1.1, and 1.1, whereas the Langmuir constant qm was found to be 1.85, 2.41, 3.54, and 2.28 mg/g at 25–60 °C. Furthermore, adsorption follows a pseudo-second-order rate constant of (3.08, 3.24, 3.24, and 13) g/mg/min under identical temperature conditions, as opposed to a first-order rate constant of 4, 3, 2.6, and 2. Hg2+, NH4+, Cl−, Br−, NO3−, SO42−, Na+, K+, H2S, and CH3SH were all extracted from wastewater by this application.

Observed changes in the climate and snow dynamics of the Third Pole

The Third Pole (TP) is the world’s largest highland and has one of the biggest reservoirs of glacier ice mass and snow cover on the Earth. Three major Asian rivers (the Indus, Ganga and Brahmaputra) are nourished by the melting of glaciers and snow in Central Himalaya, which are inevitable for the socioeconomic sustainability and water security of South Asia. Here, we investigate the long-term (1980–2020) changes in snow depth and precipitation in TP, where major precipitation occurs in the form of rainfall in summer, and snowfall in winter and spring. The seasonal mean snow depth is deep (≥1 m) in winter and shallow (≤0.2 m) in summer. The average snowmelt and snow water equivalent are higher in the central and western Himalaya and Karakoram ranges in spring, which are the regions with most glaciers in TP. There is a significant positive trend in total precipitation, about 0.01–0.03 mm d−1 yr−1 in the central and eastern TP during the South Asian Summer Monsoon for the 1980–2020 period. Snowmelt is also increasing (>0.5 × 10−3 mm yr−1) in the western Himalaya during spring, which is consistent with the temperature rise (0.04–0.06 °C yr−1) there. In addition, there is a notable increase in the annual mean glacier melt (here, the water equivalent thickness) in TP (−1 to −5 cm w.e. yr−1), with its highest values in the eastern and central Himalaya (−3 to −5 cm w.e. yr−1), as estimated for the period 2003–2020. On top of these, by the end of the 21st century, the Coupled Model Intercomparison Project Phase 6 (CMIP6) projections show that there would be a significant decrease in snow depth and an increase in temperature of TP in all shared socioeconomic pathways (SSPs). Henceforth, the increasing trend in temperature and melting of snow/glaciers in TP would be a serious threat to the regional climate, water security and livelihood of the people of South Asia.

Comparative Study of Simulation of Temperature Rise in Ring Main Unit

Comparative Study of Simulation of Temperature Rise in Ring Main Unit

Effects of different load variation rates on the operational stability in an S–CO2 Brayton cycle coupled natural circulation lead-cooled fast reactor

The thermal inertia results in net heat absorption in natural circulation lead-cooled reactors during power variation processes, increasing the risk of core meltdown. In this study, a dynamic simulation model of a natural circulation lead-cooled fast reactor coupled with a supercritical carbon dioxide Brayton Cycle power generation system has been developed based on Vpower. The influence of thermal inertia on system operating temperature under different power variation rates was discussed. The results indicate that during power reduction, different decline rates only affect the temperature variation range of the system without impacting the final stable state. However, during power increase, different ramp rates not only affect the temperature variation range but also lead to varying degrees of system temperature rise. To address this issue, an optimized turbine throttling scheme is proposed. Compared to the original plan, the new plan successfully stabilizes the temperature at the rated value after increasing the system power. This study provides insights for the operation control strategy of similar reactor types.

Facilitated core-edge integration through divertor nitrogen seeding in the HL-2A tokamak

Abstract Divertor detachment with the sustainable high-performance plasmas has been achieved through divertor nitrogen seeding in the HL-2A tokamak. The closed divertor structure facilitates achieving high divertor neutral pressure due to its efficient particle containment effect as demonstrated by both experimental and SOLPS simulation results, which aids in achieving the divertor detachment. The radiative divertor is conducive to high-frequency small ELMs operation, characterized by the reduced pedestal ion temperature gradient ∇T_i and the enhanced electron density gradient ∇n_e. The presence of minority nitrogen at the edge plasma, which results from the divertor nitrogen seeding, contributes to the rise of ion temperature T_i in the confinement region by suppressing the turbulence through the impurity dilution effect and E×B shear. The increased ion temperature T_i and electron density n_e compensate the energy loss resulted from the increased edge radiation during detachment, which contributes to the confinement sustainment combined with reduced pedestal energy loss caused by small ELMs. This work advances our understanding on the fundamental physics governing the closed divertor detachment with sustainable high-performance plasmas through divertor nitrogen seeding.

SENSITIVITY OF THE KOLYMA RIVER RUNOFF TO MODERN CLIMATE CHANGE

The Kolyma River is a large river in the continuous permafrost zone. Its basin is subject to significant climatic changes. An information-modeling complex ECOMAG is employed for the study of water regime features and dynamics. ECOMAG calculates daily water flow rates at specified points based on meteorological data with a one-day resolution.This study analyzes the actual dynamics of water runoff and runoff-forming factors during the period from 1979 to 2013. A physical-mathematical model is adapted for the Kolyma River basin. Furthermore, the study examines the sensitivity of water regime characteristics to changing climate parameters. Calibration and verification demonstrated the ECOMAG’s ability to accurately reproduce observed water discharges for two points on the Kolyma River and the satisfactory performance on its tributary, the Bolshoy Anyui River. The ECOMAG model was for the first time employed for the Kolyma River basin, thus allowing the investigation of climate-related runoff changes. The preliminary statistical analysis revealed that if the average hydrological characteristics in the Kolyma River basin from 2000 to 2013 are compared with those from 1979 to 1999 a 5,1% rise of annual river runoff is evident for the Kolymskoye river section 283 km upstream the Kolyma River mouth (from 99,4 km3 in 1979-1999 up to 104,5 km3 in 2000-2013). The ECOMAG model also effectively captures changes in the annual water runoff and its intra-annual distribution.A rise in the mean annual air temperature by 1,3°C is characteristic of the modern time period. According to weather station data, the air temperature in March, April, November, and December increased by more than 2,5°C. The total annual precipitation increased by 8,3%, with September and March experiencing the most pronounced growth.To gain a more comprehensive understanding of the mechanisms governing the Kolyma River’s response to climate changes, the sensitivity of water runoff characteristics to air temperature and precipitation changes was analyzed using the ECOMAG model to generate artificial meteorological data series. The study demonstrates that water discharge is more sensitive to a 5% increase in precipitation than to a 1ºС rise in air temperature.

Synergistic adsorption of methylene blue using ternary composite of phosphoric acid geopolymer, calcium alginate, and sodium lauryl sulfate.

The removal of dyes from the aquatic ecosystem is necessary being a major threat to life. For enhanced remediation of methylene blue (MB) dye, a new ternary biopolymer-geopolymer-surfactant composite adsorbent is synthesized by combining phosphoric acid geopolymer (PAGP), calcium alginate (Alg), and sodium lauryl sulfate (SLS). During the synthesis of the composites, PAGP and SLS were mixed with the alginate matrix, producing porous hybrid beads. The PAGP-SLS-alginate (PSA) beads prepared were characterized using different analytical tools, i.e., scanning electron microscopy (SEM), Fourier transform infrared spectrophotometry (FTIR), X-ray diffractometry (XRD), surface area and porosimetery (SAP), and thermogravimetric analysis (TGA). To ascertain the ideal conditions for the adsorption process, a batch reactor procedure was used to investigate the effects of several parameters on MB adsorption, including pH (2, 4, 6, 8, 10), PSA adsorbent dosage (0.06-0.12 g), MB concentration (50-500 mg/L), contact time (15 to 300 min), and temperature (25, 35, and 45 °C). The SEM investigation indicated that ~ 1860 μm-sized PSA beads with 6-8 μm voids are generated. Based on XRD, FTIR, and SAP examinations, the material is amorphous, having numerous functional groups and an average pore size of 6.42 nm. Variation of pH has a little effect on the adsorption process, and the pH of 7.44 was found to be the pHpzc of the PSA beads. According to the findings of the batch study, equilibrium adsorption was obtained in 270-300 min, showing that the adsorption process was moderately slow-moving and effective. The dye adsorption linearly increased with initial dye concentration over concentration range of 50-500 mg/L and reciprocally decreased with rise in temperature. 0.06 g adsorbent dose, 25 °C, pH10, and 270 min were found to be the better conditions for adsorption experiments. Langmuir isotherm fitted well compared to Freundlich, Temkin, and Dubinin-Radushkevich (DR) isotherm models on the experimental data, and the maximum adsorption capacity(qmax) calculated was 1666.6 mg. g-1. Pseudo-second-order (PSO) kinetics model and multi steps (two) intra particle diffusion (IPD) model fitted well on the adsorption kinetics data. The system's entropy, Gibbs free energy, and change in enthalpy were measured and found to be -109.171 J. mol-1. K-1, - 8.198 to - 6.014 kJ. mol-1, and - 40.747 kJ. mol-1. Thermodynamics study revealed that adsorption process is exothermic, energetically favorable and resulting in the decrease in randomness. Chemisorption is found to be the dominant mechanism as confirmed by pH effect, Langmuir isotherm, PSO kinetics, IPD model, and thermodynamics parameters. PSA beads were successfully regenerated using ethanol in a course of 120 min and re-used for five times. To sum up, the PSA adsorbent's impressive adsorption capability of 1666.66 mg/g highlights its potential as a successful solution for methylene blue removal. The results of this study add to the expanding corpus of information on sophisticated adsorption materials and demonstrate PSA's potential for real-world uses in wastewater treatment and environmental clean-up.

Radiocarbon dating of naturally shed reindeer antlers melted out of retreating and down-wasting ice patches and ice caps in western Norway

A rise in summer temperatures, especially since the turn of the 21st century, has caused negative mass balance and marginal retreat of ice caps and ice patches in western Norway. Twentytwo naturally shed reindeer antlers found at retreating and down-melting margins of fourteen retreating ice patches and ice caps on mountain summits in western Norway during the recent decades have been radiocarbon dated. The reindeer antlers show no evidence of being sawed or cut off the skull or any engravings/scrape marks if the antlers had been handled by humans. The oldest reindeer antler in this study dates at 2201-2132 cal. yr BCE. Four dated antlers fall within the age range 2300-2000 cal. yr BCE. Single dates fall within the time ranges 1100 to 1000, 900 to 800, and 500 to 300 cal. yr BCE. Four dated antlers are within the time range 200 BCE to 100 cal. yr CE and two dated antlers fall within the time range 600 to 800 cal. yr CE. Finally, fifteen dates fall within the time range 1300-1900 cal. yr CE, the highest number (n=11) between 1300 and 1600 cal. yr CE. The temperature decline and increased precipitation causing advancing glaciers and ice caps, accompanied by growing ice patches during the Neoglacial period, including the early phase of the Little Ice Age, provided good preservation conditions for the reindeer antlers during the Little Ice Age, with extensive ice and snow cover in the high mountains in western Norway.

Impact of high-energy electron beam irradiation on piezoelectric properties of lead zirconate titanate

Abstract We measured the resonant and anti-resonant frequencies of lead zirconate titanate (PZT) elements at various temperatures and investigated the change in the electromechanical coupling coefficient to clarify the temperature dependence of the elements. Based on these results, we performed a 20 MeV electron beam irradiation experiment on the PZT elements. We found that the electromechanical coupling coefficient decreased as the cumulative energy absorption due to beam irradiation increased, even when the effect of the temperature rise due to beam irradiation was negligible.

A Comprehensive Examination of the Effects of Climate Change on Maternal, Fetal, and Neonatal Health: An In-Depth Review

The substantial elevation in atmospheric greenhouse gas levels is a consequence of human activities, resulting in a 1.1°C elevation in surface temperature as the worldwide average. The detrimental outcomes of this temperature rise encompass severe weather events, deterioration in food, water, and air quality, alongside an escalation in vector-borne infectious diseases and/or transmission risks. The mitigation and adaptation to climate change are pivotal factors for the survival of humanity in the midst of this existential crisis. Climate change exerts notable effects on maternal, fetal, and neonatal health, with women experiencing more adverse impacts compared to men. Pregnant women may face conditions such as hypertensive disorders like preeclampsia and eclampsia, gestational diabetes mellitus (GDM), variations in pregnancy duration, and mental health disorders. Fetal and newborn health can be affected, leading to results like preterm birth (

Inherent Thermal-Noise Problem in Addressing Qubits

Qubit-specific measurement in a superconducting quantum processor requires physical interconnects that traverse 4 orders of magnitude in temperature from 293 K to 10 mK. Although the quantum processor can be thermalized and shielded from electromagnetic noise, the interconnects themselves introduce an unavoidable remote heat bath that causes decoherence of quantum states. In the present work, we report quantitative and device-independent measurements of the power radiated to the quantum processor from its control lines. Our results have been obtained using a calibrated bolometer that operates within a millikelvin environment with time-resolved measurement capability. In the limit of zero applied power, the noise power emitted to the quantum processor is equivalent to that of a blackbody with temperature 63–71 mK for the prototypical drive lines in the study. Experimentally, we increase the applied power of a simulated control signal to map out the resulting temperature rise and thermal time constant of five prototypical drive-line varieties. We input the data to an open quantum system model to demonstrate the trade-off between dissipated signal power, transmon-qubit lifetime, pure dephasing, gate fidelity, and the implied decoherence rates due to self-heating during microwave operations. Beyond explaining dephasing rates observed in the literature, our work sets the stage for accurate noise modeling in novel quantum computer interfacing methods due to our device-agnostic approach. Published by the American Physical Society 2024

Effect of Channel Depth Ratio and Absorber Plate Configuration on Performance of a Solar Air Heater

An experimental evaluation of the effect of channel depth ratio and absorber plate configuration on the performance of a baffled counter flow double-pass solar air heater (BCDSAH) is main objective of current work. The BCDSAH was constructed so as to permit adjustments of channel depth ratio (CDR) to 2, 3 and 4. During experimentation, the lower channel depth was kept at 50 mm while the upper channel depth was adjusted to 100 mm, 150 mm and 200 mm, yielding various channel depth ratios. The assessments were conducted for three configurations of absorber plate: (i) flat absorber plate, (ii) baffled absorber plate and (iii) baffled absorber plate with phase change material (PCM). The performance of the BCDSAH was evaluated at an air mass flow rate of 0.07 kg/s for temperature rise, useful heat gain (UHG), energy efficiency, and exergy efficiency. For CDR = 2 and a baffled absorber plate with PCM, the obtained average values of temperature rise, UHG, energy efficiency and exergy efficiency were 15.3 oC, 1075.2 W, 76.2% and 2.7% respectively. For the baffled absorber plate with PCM, increases of 8.5%, 9.4%, 10.1% and 10.9% were obtained in temperature rise, UHG, energy efficiency and exergy efficiency respectively for CDR = 2 compared to CDR = 4. Finally, a value of CDR = 2 and a baffled absorber plate with PCM are suitable for applications like drying of agricultural products and space heating.

Maize migration mitigates the negative impact of climate change on China’s maize yield

Crop migration as an adaptation to modulate climate change’s impact on crop yields presents both benefits and risks. We explored how maize migration in China modulates yield responses to climate change and quantified the potential economic benefits of maize migration as an adaptation strategy. We employed a panel data model to identify and measure the factors driving the relocation of maize area, linear regression to quantify the effects of maize migration on climate exposure and irrigated area, and an econometric model to estimate the effects of maize migration on yield. The results show that rise in temperature has a significant negative effect on maize area and that precipitation has a significant positive effect. The migration of maize area is driven by socio-economic factors including agricultural gross domestic product, power of farming machines, and fertilizer input. Moreover, expanded irrigation reduces the adverse effects of high temperatures on maize yield, thereby influencing adaptive crop migrations. The beneficial effects of maize migration are primarily achieved by reducing the adverse effects of extreme heat and strengthening the positive effects of irrigation. However, the extent of this adaptation is jointly affected by agricultural policies, irrigation infrastructure, and economic factors. Current market-oriented agricultural policies may be effective in guiding spatial shifts in maize distribution to align with climate-driven changes, potentially decreasing the vulnerability of China’s maize yield to the impact of climate change. China’s food security policies need to consider climate-driven spatial shifts in crop cultivation and enhance food subsidy policies to highlight the benefits of investment in climate change adaptation, such as adjusting cropping acreage and irrigation to farmers in North China.

Solubility determination, model evaluation, molecular simulation and thermodynamic analysis of Dehydroacetic acid in thirteen pure solvents

The solid–liquid equilibrium solubility of DHA in thirteen pure solvents (methanol, ethanol, n-propanol, isopropanol, n-pentanol, ethyl formate, ethyl acetate, N, N-dimethyl acetamide (DMA), N, N-dimethyl formamide (DMF), acetonitrile, acetone, 2-butanone, dimethyl sulfoxide (DMSO)) was determined at temperatures ranging from 288.15-323.15 K under local atmosphere by gravimetric method. The experimental results showed that the solubility of DHA was positively correlated with the rising of temperatures. Five thermodynamic models, including Ideal model, Apelblat model, λh model, NRTL model and Wilson model, were employed to fit the experimental data and Wilson model provided a better correlation. The KAT-LSER model and molecular dynamic simulations were also carried out to investigate the effects of solvent–solute interactions on solubility. Furthermore, the thermodynamic properties of the dissolution process were calculated and the results argued a spontaneous, exothermic and entropy-driven process.

Hygrothermal aging mechanism of epoxy composites used for medium-frequency transformers

The integration of medium-frequency transformer design and the harsh service environment raise higher demands for the medium-frequency insulation performance of epoxy composites. As epoxy composite's frequency response characteristics and sensitivity to moisture intrusion are still unknown, its application as the insulation materials of medium-frequency transformers under hygrothermal conditions is limited. This paper investigates the mechanism of moisture intrusion damage to the molecular structure of the epoxy resin matrix and its cross-linking points with the curing agent. The regularity of medium-frequency insulation performance degradation of epoxy composites after hygrothermal aging is studied. Results indicate that after 40 days of hygrothermal aging, moisture together with high temperature damaged the main chain of the epoxy resin and its cross-linking points with the curing agent, resulting in a 23°C decrease in the glass transition temperature and an 82% decrease in cross-linking density of the epoxy composite. Moisture ionization and the increase of carriers due to epoxy resin hydrolysis lead to an increase in the amount of space charge. The temperature rise caused by dipole steering polarization facilitates the formation of internal conductive pathways in the epoxy composite, resulting in a 73% decrease in the medium-frequency breakdown strength and a four-order magnitude decrease in the medium-frequency volume resistivity of the epoxy composite. This study can guide the insulation design of high-reliability medium-frequency transformers.

Prediction of the heat of hydration of fly ash concrete by adiabatic temperature rise test and regression analysis

This paper deals with the proposal of a model that can predict heat of hydration of concrete containing fly ash and the adiabatic temperature rise test results that are the basis of the model. For the adiabatic temperature rise tests, total of twelve concrete mixtures were prepared with variables of the percentage of fly ash replacement and w/cm. The test results indicate that the replacement of fly ash significantly reduces the adiabatic temperature rise and delays the early hydration of fly-ash blended cements. Additionally, w/cm was found to influence not only the maximum adiabatic temperature rise but also the slope of the temperature rise. Therefore, a regression analysis was conducted to propose three parameters (hydration time parameter, hydration slope parameter, ultimate degree of hydration) for the heat of hydration model of concrete containing fly ash. The developed heat of hydration model was validated using test data. Models that did not consider w/cm, similar to those proposed by other researchers, failed to accurately predict the test results. However, the final model developed, which incorporates w/cm, accurately predicted the test results, as confirmed through this study.

Numerical simulation of geothermal reservoir thermal recovery of heterogeneous discrete fracture network-rock matrix system

In contrast to previous methodologies utilizing smooth fractures for predicting production in fractured geothermal reservoirs, this study introduces a novel approach employing a non-uniform rough discrete fracture network model characterized by heterogeneous apertures. Partial differential equations governing dual porosity flow and heat transfer are formulated, followed by a multi-physical field coupling simulation for the reservoir-scale formation model. The investigation focuses on the 50-year production performance of an enhanced geothermal system (EGS) under various parameters. Findings indicate a 15 % increase in production temperature with a 10-degree rise in injection temperature and a 10 % increase when well spacing is halved. Conversely, doubling the injection velocity or increasing the fracture aperture from 2 mm to 5 mm results in a 20 % and 25 % decrease in production temperature, respectively. These results highlight the negative impacts of faster fluid movement and larger fracture apertures on thermal retention. Conventional smooth fracture networks tend to underestimate both production temperature and the operational lifespan of EGS. An effective flow rate is defined, and an empirical prediction model for thermal recovery is established. This study provides valuable insights into the interplay of parameters affecting EGS production performance, serving as a pertinent reference for analyzing the influence of heterogeneous apertures on geothermal reservoirs.

An effective parametric sensitivity analysis to improve electrical and thermal energy/exergy efficiency of PVT system using nanofluid

A 3D steady-state model of a photovoltaic/Thermal system with nanofluid is studied to investigate the electrical and thermal performance of PVT by utilizing a combination of statistical modeling and numerical simulation. The 3D CAD (Computer Aided Design) modeling of the photovoltaic thermal (PV/T) is performed using Ansys Space Claim. The current study is based on using a 2-way coupling FSI approach for modeling nanofluid-based PVT systems. Five output responses electrical power, thermal power, electrical exergy, thermal exergy, and entropy generation are chosen against four input parameters, solar radiation (G_sun), ambient temperature (Tamb), mass flow rate (ṁ), and nanoparticles concentration % (φ) to analyze system performance. A statistical prediction model is developed using response surface methodology (RSM) that starts from the design of experiment (DOE). The predicted outcomes obtained from the statistical model and the numerical simulation of the heat transfer model exhibit the existence of good fitness. Furthermore, optimization is performed using RSM for various optimization objectives to suggest the ideal design parameter values for optimal system performance. Sensitivity analysis illustrates that a rise in ambient temperature causes a drop in electrical power production and leads to an increase in thermal power. However, the increase in solar radiation boosts electrical power and causes a drop in thermal exergy, entropy generation increases with an increase in solar irradiation. Similarly, an increase in mass flow rate leads to an increase in thermal power. Multi-objective optimization with the highest composite desirability values depicts the influence of input design parameters and has a favorable effect on the objective of concurrently maximizing electrical and thermal power.