Effect Of Temperature Research Articles

Pyrolytic conversion of Mesua ferrea testa to nitrogen-doped porous carbon for supercapacitor applications

Developing a high energy density supercapacitor is of great challenge due to the low surface area of commercial activated carbon. The present work aims at developing highly porous nitrogen-doped porous carbon from biomass for supercapacitors. Herein, Mesua ferrea (Nahor) shells, a widely available biomass in northeast India, was used to prepare porous carbon. The effect of activation temperature on structural, textural properties, and electrochemical performance is studied. The carbonization temperature highly influenced the pore structure, porosity, surface area, and thereby influencing the electrochemical performance. The porous carbon pyrolyzed at 700 °C delivered a high specific capacitance of 210 F g-1 at 1 A g-1, higher than porous carbon made at higher temperature (27.5 F g-1 at 1 A g-1 for carbon pyrolyzed at 800 °C). The results provide insights that will be of use in the development of high-energy-density capacitors employing biomass-derived porous carbon.

Effect of Extrusion Temperature on the Microstructure, Mechanical Properties, and In Vitro Corrosion Behavior of a Biodegradable Mg-Zn-Ca-Mn-Sn Alloy

Effect of Extrusion Temperature on the Microstructure, Mechanical Properties, and In Vitro Corrosion Behavior of a Biodegradable Mg-Zn-Ca-Mn-Sn Alloy

Mitigating cold stress in rice: a study of genotype performance and sowing time

Rice (Oryza sativa L.) is an essential food for half of the global population and is vital in maintaining global food security. Climate change, increasing population and recent incident of COVID pandemic has generated financial burden and threaten the global food security. Due to theses factors rice cultivation also has to face significant challenges. frequent weather changes pose a considerable challenge to agricultural planning, which was previously relaying on consistent seasonal variations. In this context, rice cultivation is particularly sensitive to cold, where its development and productivity inhibited by low temperatures (< 18 °C). Developing rice varietes with low temprature tolerence and good yield potential is one of the major goals of current breeding efforts of plant scientists. For this purpose, short duration and early rice varieties are most favorable to avoid cold stress and yield more in less number of days. this study was designed to investigate the effect of low temperatures on different rice varieties. the study was designed to identify low temprature tolerent genotypes with early and regular cultivation. For this, thirty-four genotypes were evaluated in two gorwing seasons (2018–2019) with four different sowing times. Statistically sowing time showed significant interaction between all yield contributing parameters. The data indicate that exposure to low temperatures during the reproductive phase prolongs the maturation period of the crop, also length of the panicle and the fertility of the spikelets drops, resulting in a significant decrease in the production of sensitive varieties. Some varieties are more sensitive to cold stress compared to others. In the Egyptian context, Giza176, Sakha104, and Sakha107 are recommended for early cultivation, while the genotypes Giza 179, Sakha101, Sakha104, and GZ 9730-1-1-1-1 are indicated for the normal cultivation period. The Sakha104 variety is particularly notable, as it is recommended for both purposes. In addition, the data obtained in this study provide valuable information for selecting rice varieties suitable for double cropping in the North Delta of Egypt. This study also contributes to the existing literature, providing insights into the resilience of rice cultivation in the face of climate change.

Investigation of the role of sintering temperature on microstructure, ac conductivity, and dielectric constant of single phase NiSnO3 nanopowder

This study investigates the effect of sintering temperature on the structural and electrical properties of co-precipitated nickel stannate (NiSnO3) nanopowder. Sintering temperatures, determined using Thermo Gravimetric Analysis (TGA), reveal a pure hexagonal perovskite structure through X-ray diffraction (XRD) analysis. Crystallite size increased from 10.56 nm to 26.04 nm and lattice strain decreased from 23.05×10−3 to 2.35×10−3 with higher sintering temperatures, analyzed via the Scherrer formula. d-spacing values from SAED patterns align with XRD results, and TEM analysis shows particle size growth from ∼11.43 nm to ∼28.16 nm as sintering temperature rises from 600°C to 900°C. Elemental composition has been confirmed through EDX, and elemental mapping analysis. Impedance spectroscopy via Cole-Cole plots indicated non-Debye-type or multiple relaxations with depressed semicircles due to grain and grain boundary effects. The sample sintered at 900°C exhibits the highest conductivity (8.35×10−5 Ω−1cm−1) with lowest activation energy of 0.31 eV and maximum dielectric constant values, with a minimum relaxation time of 0.00029 sec. Also the frequency variation of Z′′ and M′′ confirm the presence of non-Debye type relaxation. Scaling behavior of the imaginary part of complex impedance and conductivity spectra confirms temperature-independent conduction and relaxation mechanisms. These materials are used in energy storage applications.

Propagation and evaporation of contaminated droplets, emission and exposure in surgery environments revealed by laser visualization and numerical characterization

The contaminated liquid mixture containing mucosalivary fluid and blood would be aerosolized during medical procedures, resulting in higher-risk exposures. The novelty of this research is integrating laser visualization and numerical characterization to assess the propagation and evaporation of contaminated droplets, and the interactive effects of humidity and temperature on exposure risks will be numerically evaluated in surgery environments. The numerical model evidenced by experiments can predict the mass balance of ejection droplets, the minimum required fallow time (FT) between appointments, and the disinfection region of greatest concern. Around 98.4 % of the ejection droplet mass will be removed after the cessation of ultrasonic scaling, while the initial droplet size smaller than 72.6μm will dehydrate and become airborne. The FT recommendation of 30 min is not over-cautious, and the extended FT (range of 28–37 min) should be instituted for low temperature (20.5 °C) and high humidity levels (60 %RH). The variation of the temperature and humidity in the range for human thermal comfort has little influence on the area of the disinfection region (0.15m2) and the cut-off size (72.6μm) of droplet deposition and suspension. This research can provide scientific evidence for the guidelines of environmental conditions in surgery rooms.

Effects of polishing disc material and substrate surface temperature on the tribological behaviors and machining results of β-Ga2O3(100)

Effects of polishing disc material and substrate surface temperature on the tribological behaviors and machining results of β-Ga2O3(100)

Thermodynamic analysis of a solar-assisted supercritical water gasification system for poly-generation of hydrogen-heat-power production from waste plastics

The resource utilization of waste plastics is an effective approach to address the issue of energy shortage. In this study, a comprehensive disposal system for polypropylene plastics was designed by supercritical water gasification coupled with a solar heat collector for poly-generation of power, hydrogen, and heat. The study first demonstrated the transfer behavior and exchange capacity of different streams throughout the entire system. It was found that the disposal system maintained mass conservation by checking the material streams. The thermodynamic results indicated that the largest exergy losses occurred in the oxidizer, accounting for 50.2 % of the total system exergy loss, followed by the heat exchanger at 14.51 %, with other units remaining below 10 %. A sensitivity analysis demonstrated that feedstock concentration significantly impacted exergy efficiency and output steams. Exergy efficiency rose from 49.5 % to 58 % as feedstock concentration increased from 5 wt% to 20 wt%. In contrast, changes in oxidation temperature had a slightly impact, with output power rising slightly from 9089 kW to 9598 kW. The effect of gasification temperature was intermediate between them. Finally, an optimal gasification conditions achieved 58.47 % exergy efficiency at 800 °C gasification, 960 °C oxidation with 5 wt% feed, producing 9496 kW of power, 76.2 kg/h of hydrogen, and 144.7 t/h of hot water.

Heat transfer processes in 'Shine Muscat' grapevine leaves in solar greenhouses under different irrigation treatments

The use of solar greenhouses in China is increasing because they permit environmental conditions to be controlled. Studies of the heat transfer processes in the leaves of plants cultivated within solar greenhouses are needed. Here, we studied heat transfer processes in 'Shine Muscat' grapevine leaves under moderate deficit irrigation (MDI), severe deficit irrigation (SDI), and full irrigation (FI) treatments under varying weather conditions. The stomatal conductance, leaf temperature, and transpiration rate of both shade and sun grapevine leaves were measured, and the effects of ambient temperature and relative humidity on these variables were determined. A thermal physics model of the leaves was established to explore the heat dissipation process. On sunny days, the transpiration heat transfer of sun leaves in the MDI, SDI, and FI treatments was 2.62 MJ m−2·day−1, 2.44 MJ m−2·day−1, and 3.86 MJ m−2·day−1and 0.818 MJ m−2·day−1, 0.782 MJ m−2·day−1, and 1.185 MJ m−2·day−1 on rainy days, respectively. There was a significant difference in transpiration heat transfer under fully irrigated and deficit irrigation conditions under different weather conditions. Furthermore, transpiration heat transfer accounted for 41.49 % and 25.03 % of the total heat transfer of sun leaves in the FI treatment and 33.94 % and 29.43 % of the total heat transfer of shade leaves on rainy days, respectively, indicating that relative humidity plays a key role in determining transpiration heat transfer and leaf temperature and that its effect was greater on sun leaves than on shade leaves.

The influence of coupling effect between stress and high temperature on the degradation of microstructure and hardness in P91 steel

Interrupted aging and creep tests were performed in the condition of 650 °C/70 MPa for P91 steel. The mechanisms of hardness and microstructure evolution during aging and creep were studied through hardness test, SEM/EBSD and TEM/EDS. By comparing the difference between aging and creep, the coupling effect of temperature and stress in P91 steel was elucidated. Results show that creep stress could accelerate the entire degradation process in P91 steel. Firstly, the dislocation density increased rapidly at the beginning of creep, and then decreased also at a high rate after reaching its peak value. On the other hand, the dislocation density decreased slowly in aging condition. Additionally, with the migration of grain boundaries under creep stress, some intergranular M23C6 entered inside grains and afterwards dissolved into matrix. On the other hand, other M23C6 which remained intergranular continuously ripened and congregated with time, and finally turned into large ones at triple junctions of grain boundaries. Furthermore, stress had the greatest impact on dislocation density, whereas temperature affected volume fraction of M23C6 the most. In creep condition, the degradation of mechanical properties of P91 steel was mainly caused by the reduction of dislocation strengthening which was followed by grain boundary strengthening.

Early life exposure to high temperature enhances locomotor performance without alteration in thermal ecology in different populations of Thoropa taophora tadpoles (Anura, Cycloramphidae).

Understanding the intricate relationship between temperature and physiological processes in ectotherm vertebrates is crucial for predicting how these animals respond to environmental changes, including those associated with climate change. This is particularly relevant for the anurans, given their limited capacity for thermoregulation, particularly in larval stages. Herein, we investigated the capacity for thermal acclimatization in Thoropa taophora tadpoles, an endemic species in the Atlantic rainforest of Southeast Brazil, inhabiting distinct thermal environments. These semi-terrestrial tadpoles develop on rocky surfaces with some populations inhabiting exposed regions near the marine coast where temperatures may reach up to 30 °C in sunny conditions, while other populations occupy forested areas near waterfalls that maintain lower temperatures. We aimed to understand the effects of temperature on locomotor performance and on the activity of metabolic enzymes that support performance in tadpoles sampled in four different populations. Moreover, we measured several aspects of thermoregulation including the critical thermal maximum (CTmax), the body temperature of activity (Tb), the preferred temperature (Tpref) and the effectiveness of thermoregulation (E). Despite differences in body size, tadpoles from warmer environments consistently demonstrate higher locomotor performance, with minimal or no acclimatization seen in other variables. Correlations between habitat temperature and biological endpoints underscore the significance of maximum locomotor performance in shaping physiological responses. Our results show how temperature can impact tadpole behavior and performance, without change in many organismal measures of thermal acclimatization, providing insights into potential ecological implications, particularly in the context of climate change.

Improving CZTS/ZTO solar cell efficiency with inorganic BSF layers

Copper zinc tin sulfide (CZTS) thin-film solar cells have garnered significant attention in the solar energy sector. This study aims to enhance the performance of CZTS solar cells by replacing the conventional, toxic CdS buffer layer with Zn1−xSnxO (ZTO) for x = 0.2. Utilizing the one-dimensional solar cell capacitance simulator (SCAPS-1D) and informed by experimental data on the physical properties of the solar cell layers, we investigated the effects of thickness, doping density, and defect density of the CZTS absorber layer on the cell’s performance. Initially, an efficiency of 14.76% was achieved. To improve this efficiency, an inorganic back surface field (BSF) layer was incorporated to mitigate charge carrier recombination at the absorber/back contact metal interface. Various materials, including CuO, Cu2O , Mo S2 and Mo Se2 , were evaluated as potential BSF layers. Comparative analysis indicated that the inclusion of the BSF layer significantly enhances the solar cell efficiency, achieving up to 27% with Cu2O as the BSF material. Furthermore, the study included an analysis of temperature effects and parasitic resistances to comprehensively assess the solar cell’s performance.

Simultaneously achieving high Li leaching efficiency and Li/Co selectivity from lithium-ion batteries cathode by using natural low-melting mixture solvents (LoMMSs) as green solvents

Simultaneously achieving high Li leaching efficiency and Li/Co selectivity from lithium-ion batteries cathode at mild condition with high sustainability is difficult up to now. To achieve this goal, we here utilize amino acid-based low-melting mixture solvents (LoMMSs) as green solvents. Representative LoMMSs valine:lactic acid (1:12) could leach nearly 100% Li with the high Li/Co selectivity of 48.39 from lithium cobalt oxide (LCO). Effect of temperature, time and leaching agent mass is investigated. Higher temperature continuously increases the Li leaching efficiency, while Co leaching efficiency first increases during the temperature from 25 °C to 60 °C and then decreases at higher temperature. Both Li and Co leaching efficiency when extending the time or adding the leaching agent mass. Mechanism study shows that acid-base interaction and coordination are the main interaction for the high efficiency of metal leach while redox reaction is negligible. This work would provide a useful guide for promoting the industrial application of selectively recycling lithium-ion batteries cathode with high sustainability and low cost.

Effect of Temperature on Nestmate Recognition in the Ant Odontomachus chelifer

Cuticular hydrocarbons play multiple roles in social insects. Their primary function is to waterproof the external surface of the body of individuals in order to prevent desiccation, however, they also act as a chemical signature in social insects, unique to each colony, through which individuals recognize themselves as nestmates. These compounds may undergo changes due to exogenous factors, aiming to maintain the integrity of the cuticle. However, changes in cuticular chemical composition may impair recognition among nestmates. Thus, this study tested the hypothesis that nestmates of the ant Odontomachus chelifer, when submitted to different temperature conditions, may undergo changes in their normal pattern of recognition. To do this, groups of workers were kept under two different temperatures, 15 and 30 °C, during a period of 24 hours, and then submitted to induced encounters with workers who remained for this same period at a temperature of 25 °C. As a form of control, the same type of encounter was performed between ants that remained isolated, but at the same temperature and also between ants from different colonies. The results show that ants that remain for 24 hours under different temperature conditions, present some level of difficulty in recognizing themselves as nestmates, performing more aggressive behaviors and taking longer touching themselves (antennation) than in the control condition.

Temperature effect on the microstructural refinement of equiatomic CoCrNi medium entropy alloy via cyclically multi-directional impact

Severe plastic deformation can effectively refine alloy microstructure and improve the mechanical properties of alloys surprisingly. In this work, a new approach of severe plastic deformation was proposed based on split Hopkinson pressure bar, i.e., cyclically multi-directional impact. Using this newly developed technique for microstructural refinement at different temperatures (77 K, 293 K, and 1073 K), bulk equiatomic CoCrNi medium entropy alloys with refined microstructures were obtained, and the stress vs. strain relation of the equiatomic CoCrNi medium entropy alloy during the cyclically multi-directional impact can be in situ measured. The strain rate of the cyclically multi-directional impact was controlled at about 1500 /s. The hardnesses of the CoCrNi medium entropy alloy increase dramatically from 216 Hv to 460 Hv after the cyclically multi-directional impact at 77 K, 484 Hv after the cyclically multi-directional impact at 293 K, and 434 Hv after the cyclically multi-directional impact at 1073 K. The microstructural evolutions of the CoCrNi MEA after cyclically multi-directional impact at three temperatures were characterized and analyzed. This study aims to provide a new approach to microstructural refinement for bulk alloys.

Effect of aging temperature on the microstructure and properties of alloyed high‐manganese steel

Effect of aging temperature on the microstructure and properties of alloyed high‐manganese steel

Study on electrochemical polishing mechanism of TC4 titanium alloy

To achieve a high-quality and precise surface on TC4 titanium alloy for demanding engineering applications, electrochemical polishing (ECP) technology was employed to investigate the polishing process of TC4 titanium alloy in an ethylene glycol-sodium chloride green electrolyte. The macro and micro morphology, surface roughness, material removal rate, surface elements, surface corrosion resistance, and surface hardness of TC4 titanium alloy were measured before and after polishing. Single-factor experiments were conducted to explore the effects of processing gap, electrolyte temperature, polishing voltage, and polishing time on TC4 titanium alloy surface quality. Optimal polishing parameters were determined to be an electrode gap of 12 mm, a voltage of 20 V, a temperature of 40 °C, and a polishing time of 10 min. The experimental results indicated that after electrochemical polishing, the workpiece surface roughness Ra decreased from 256 nm to 25 nm, achieving a roughness reduction rate of 90.23%, the material removal rate was 3.348 μm min−1. The self-corrosion potential of the polished surface increased from −0.416 V to −0.375 V and the self-corrosion current density decreased from 4.447 × 10−7 A·cm−2 to 1.873 × 10−7 A·cm−2, the surface indentation hardness of the workpiece decreased from 5.8669 GPa to 4.6726 GPa. Based on the characterization of polished surface, the mechanism of electrochemical polishing of TC4 titanium alloy was proposed. The results demonstrate that electrochemical polishing of TC4 titanium alloy is highly efficient, involves no mechanical action, and causes no subsurface damage, making it a promising technology to meet medical requirements.

Experimental study on the dynamics of a liquid nitrogen droplet impacting a surface under Leidenfrost conditions

Liquid nitrogen droplet impacting a superheated surface is a fundamental phenomenon of liquid nitrogen spray cooling, whereas the mechanisms behind which are still unclear. We designed and developed a visual experimental system to investigate the dynamics of a liquid nitrogen droplet impacting a superheated surface under cryogenic conditions. The impact dynamics of the liquid nitrogen droplet at the Leidenfrost state are captured, and the effects of Weber number (We) and surface temperature on the spreading and rebound characteristics of the droplet are analyzed. The findings show that the droplet exhibits spreading, retraction and rebound at a low We. Droplet spreading and rebound characteristics are mainly affected by We while insensitive to surface temperature. The maximum spreading coefficient exhibits a power-law increase with We, while the maximum rebound coefficient shows an upward and then downward trend with We. The dimensionless maximum spreading time, dimensionless residence time, and dimensionless maximum rebound time show power-law increase with We. Corresponding fitting correlations for these factors for liquid nitrogen droplets are also proposed. This study contributes to an in-depth understanding of the impact dynamics of cryogenic liquid droplet under cryogenic conditions.

Effects of soldering temperatures and composition on the microstructures and shear properties of Sn58Bi-xSAC0307/ENIG solder joints

PurposeThis paper aims to systematically study the effects of reflow temperature and SAC0307 (SAC) content on the micromorphology and mechanical properties of Sn58Bi-xSAC0307 composite solder joints to meet the requirements of high integration and low-temperature packaging of devices and provide references for the application of composite solder joints.Design/methodology/approachSn58Bi and SAC0307 solder paste was mechanically mixed in different proportions to prepare Sn58Bi-xSAC0307/ENIG solder joints. The thermal properties, microstructure and mechanical properties of the composite solder joints were studied.FindingsAs SAC content in the solder increases, the balling temperature of SnBi-SAC solder gradually increases. The addition of SAC alloy reduces the grain size of large Bi-rich phase, and there are small-sized dispersed Bi and Ag3Sn particles in the bulk solder. The intermetallic compounds composition of the SnBi-xSAC/ENIG solder joint changes from Ni3Sn4 to (Ni, Cu)3Sn4 and (Cu, Ni)6Sn5 with SAC increasing. As the soldering temperature increases, the strength of all solder joints shows a rising trend. Among them, the shear strength of SnBi-20SAC solder joints at a reflow temperature of 150°C is approximately 37 MPa. As the reflow temperature increases to 250°C, the shear strength of solder joints increases to approximately 67 MPa.Originality/valueThis study provides a reference for the optimization of low-temperature solder composition and soldering process under different package designs.

Hydrogen embrittlement of a V+Nb-microalloyed medium-carbon bolt steel subjected to different tempering temperatures

The effect of different tempering temperatures on the hydrogen embrittlement (HE) resistance of a V + Nb-microalloyed medium-carbon bolt steel was studied by slow strain rate tensile testing and hydrogen thermal analysis. The HE resistance represented by notch tensile strength σbN of hydrogen-charged specimens increases with increasing tempering temperature Ttem, and the σbN of the in situ hydrogen-charged sample is considerably lower than that of the pre-hydrogen-charged sample. Both the diffusible hydrogen content Cdiff and hydrogen-trapping capability of the precipitates show a significant increase-decrease change trend with Ttemp. The ratio of Cdiff primarily trapped by nanoscale V-rich MC precipitates increases linearly with increasing Ttemp. The control of V-rich MC through suitable increasing Ttemp is vital for obtaining the best HE resistance although at the cost of decreased strength. It is thus suggested that a compromise between strength and HE resistance should be considered for the practical application of this type of steel.

Analytical and Functional Characterization of Plasmid DNA Topological Forms and Multimers.

Plasmid DNA (pDNA) is an essential tool in genetic engineering that has gained prevalence in cell and gene therapies. Plasmids exist as supercoiled (SC), open circular (OC), and linear forms. Plasmid multimerization can also occur during the manufacturing process. Even though the SC forms are thought to provide optimal knock-in (KI) efficiency, there is no strong consensus on the effect of the topological forms and multimers on the functional activity. In addition, the results obtained for conventional pDNAs (>5 kbp) do not necessarily translate to smaller pDNAs (∼3 kbp). In this study, a workflow was developed for the analytical and functional characterization of pDNA topological forms and multimers. An anion exchange chromatography (AEC) method was first developed to quantify the topological forms and multimers. Four AEC columns were initially compared, one of which was found to provide superior chromatographic performance. The effect of mobile phase pH, various salts, column temperature, and acetonitrile content on the separation performance was systematically studied. The method performance, including precision and accuracy, was evaluated. The final AEC method was compared to capillary gel electrophoresis (CGE) by analyzing several pDNA sequences and lots. A forced degradation study revealed unexpectedly high degradation of the SC forms. Finally, the KI efficiency was compared for the SC and OC forms, and the multimers.