Temperature Rise Research Articles

Can Aluminum Cations Promote Nucleation for THF Hydrate Growth?

Rapid nucleation of tetrahydrofuran (THF) hydrate is essential for developing a THF hydrate-based cold storage technology. Earlier works have hypothesized the role of aluminum complexes in initiating the nucleation of clathrate hydrates using aluminum metal electrodes and substrates. This study investigates if the nucleation promotional effect of hydrate can be achieved using the aluminum salt, AlCl3, due to the formation of aluminum aqua complexes in water. Metal chlorides NaCl and MgCl2 are also utilized to evaluate the effect of cation type in initiating nucleation, i.e., the effect of charge/radius ratio. The induction time is measured in a stirred reactor at various subcoolings and concentrations of 0.05, 0.1, 0.5, 1, and 2 wt %. The nucleation time is studied in two reactor configurations based on the nature of salt introduction in the THF solution, i.e., salt premixed in solution and salt injected inside the solution. The sudden rise in the reactor temperature due to hydrate formation is used as an indicator of hydrate formation. Results indicate that AlCl3 promotes hydrate nucleation as AlCl3 reduces induction time by 92.2% at 0.05 wt % concentration compared with water. Nearly instantaneous nucleation is also achieved by directly injecting AlCl3. MgCl2 and NaCl do not show a similar effect on induction time as AlCl3. The pH and Raman spectra measurements with and without salts are carried out to explain the effect of cations on the THF-water solution.

MR Safety of Inductively Coupled and Conventional Intraoral Coils.

Intraoral coils (IOCs) in magnetic resonance imaging (MRI) significantly improve the signal-to-noise ratio compared with conventional extraoral coils. To assess the safety of IOCs, we propose a 2-step procedure to evaluate radiofrequency-induced heating of IOCs and compare maximum temperature increases in 3 different types of IOCs. The 2-step safety assessment consists of electric field measurements and simulations to identify local hotspots followed by temperature measurements during MRI. With this method, 3 different coil types (inductively coupled IFC, transmit/receive tLoop, and receive-only tLoopRx) were tested at 1.5 T and 3 T for both tuned and detuned coil states. High SAR and regular MRI protocols were applied for 2 coil positions. The measured E field maps display distinct hotspots for all tuned IOCs, which were reduced by at least 40-fold when the IOCs were detuned. Maximum temperature rise was higher when the coils were positioned at the periphery of the phantom with the coil planes parallel to B0. When neither active nor passive detuning was applied, maximum temperature increase of ΔT = 1.3/0.5/1.8 K was found for IFC/tLoop/tLoopRx coils. Hotspots detected by E field measurements, and simulations were consistent. In the simulations, the results were different for homogeneous phantoms compared with full anatomical models. The 2-step test procedure is applicable to different coil types. The results indicate that a risk for radiofrequency-induced heating exists for tuned IOCs, so that adequate detuning circuits need to be integrated in the coils to ensure safe operation.

Thermal modal analysis of hypersonic composite wing on transient aerodynamic heating

Considering the influence of thermal stress and material property variations, this study employs the Navier–Stokes equations and Fourier heat conduction law to establish a semi-implicit time-domain numerical analysis method for hypersonic aerothermal-structural coupling. Study the temporal variation pattern of different regions of the composite material wing under aerodynamic heating. Using the obtained transient temperature field of the wing, the thermal modal of the wing at different time points is calculated using the finite element method. Additionally, it conducts an analysis and discussion on the factors influencing the thermal modal. Composites can be effectively utilized as thermal protection materials for aircraft. During the aerodynamic heating process, the leading edge temperature reaches thermal equilibrium first, followed by the trailing edge, and the belly plate experiences a slower thermal response. Temperature rise significantly affects higher-order modes, with the change in material properties during the early stages of heating being the dominant factor. This leads to a faster decrease in natural frequency. As heat conduction progresses, the influencing factors of thermal stresses gradually increase, and the natural frequency decreases slowly or even rises.

Sweeping jet impingement heat transfer on concave surface: Influence of trapped vortex ring revealed by generalized k-ω (GEKO) model

Jet impingement-based heat transfer enhancement is widely employed due to the significant mass, momentum, and energy it accompanied. While the steady jet with high energy flux is commonly favored, it still exhibit few defects, including heat transfer deterioration away from the stagnation point and mutual flow interference in the jet arrays, which are particularly critical in demanding applications. Recently, the sweeping jet has been proposed to resolve the above challenges owing to its self-excited and self-sustaining unsteady oscillation. However, current research predominately focuses on impinging on the flat surface, neglecting impinging on the concave surface, such as internal cooling at the gas turbine blade leading-edge as well as the hot gas de-icing at the aircraft wing leading-edge. Understanding the heat transfer characteristics in these scenarios is crucial as they notably differ from those on flat surfaces. Therefore, this paper investigates the heat transfer characteristics and the related essential flow dynamics of a sweeping jet with a Reynolds number of 2577 impinging on a concave surface, and those of a steady jet under the same conditions are compared. The jet-to-wall distance and the curvature of the impingement surface are 4 and 10 times the jet's hydraulic diameter, respectively. To correctly capture the three-dimensional characteristics of the sweeping jet, this research employs the Reynolds stress model for turbulence modeling and the Generalized k-ω (GEKO) model for better calibration of the jet's spreading and dissipation rates, as well as the characteristics of trapped vortex generated due to the confined concave flow channel. The study initially focuses on the average Nusselt number on the impingement surface, revealing a 15.2% increase in heat transfer intensity of the sweeping jet compared to the steady jet, and the sweeping jet covers a larger area with enhanced uniformity. Subsequent analysis on streamlines in two perpendicular planes and Q criterion iso-surfaces in the spatial domain shows the formation of a trapped vortex ring with a constant location around the jet, restricting the effective cooling range to its inner side and thus resulting in a steep temperature rise on the two lateral sides of the vortex ring. The stability of the trapped vortex is enhanced by the curved impingement wall in the oscillation plane, which on the one hand forces the high-temperature fluid that has exchanged heat with the wall to repeatedly wash the same location, and on the other hand significantly reduces the jet oscillation angle compared to a free sweeping jet. Consequently, the heat transfer intensity of the sweeping jet is lower in the main oscillation plane than in the non-oscillation plane. Analysis of the near-wall flow parameters indicates that the sweeping jet generates higher velocity and turbulence kinetic energy in the wall jet zone far away from the stagnation point compared to the steady jet, which results in a higher local heat transfer intensity. The unsteady transverse oscillation of the sweeping jet disturbs the wall jet zone and disrupts the formation of the wall boundary layer, causing a higher velocity gradient at the wall and hence the lower thicknesses of the velocity boundary layer and the thermal boundary layer than those of the steady jet. In conclusion, this study reveals the flow and heat transfer features of the sweeping jet impingement on confined concave surface, with the influence of the trapped vortex ring mattering significantly. The findings provide a reference for designing a more effective jet arrangement. Future work will focus on investigating the effects of jet Reynolds number and impingement distance variations on the trapped vortex ring, and how to mitigate the adverse effects of the trapped vortex ring on impingement heat transfer.

Research on the thermal runaway characteristics and risks of square soft lithium‐ion batteries nail penetration

AbstractTo conduct a comprehensive investigation into the nail penetration thermal runaway (TR) characteristics of 16 Ah/5 Ah lithium‐ion batteries (LIBs) and their modules. The study aims to analyze the burst characteristics and examine the variations in TR behavior under specific conditions, with the goal of improving early warning and protection against LIB TR incidents. The research findings demonstrate that mechanical nail penetration can rapidly trigger TR, resulting in the highest temperature 522.3°C within 51.9 s, and the fastest is 20 s. In the case of LIB modules, a secondary temperature rise occurs, exhibiting an increased rate of up to 77%. Notably, when the battery bulges, there is a release of high‐temperature two‐phase heat flow accompanied by a significant discharge of combustible gases. This escalation increases the risk of further explosions. Moreover, the study observes repeated spray fires and the generation of a considerable amount of smoke. Additionally, the study highlights the role of sudden rise in temperature and the release of H2 as early indicators of TR. These findings provide valuable theoretical insights into the characteristics and risks of square soft LIBs, enhance safety measures, and contribute to the development of early warning systems for LIBs.

Determining the climate adaptive capacity of urban actors: a case study of Mongla port-townin Bangladesh

Purpose In an urban environment, different types of actors (individuals, households, community groups, institutions, governmental organizations, nongovernmental organizations (NGO), community-based organizations (CBO) and public and private organizations, etc.) play critical roles in enhancing urban resilience to adapt to the impacts of climate change. To identify and prioritize aspects of climate resilience planning, this study aims to examine the potential impacts of climate change on diverse urban systems and evaluate the capacities of various actors to adapt to climatic stress. Design/methodology/approach This research selects Mongla, a coastal as well as port town in south-western Bangladesh that faces climate risks including frequent cyclones, storm surges and salinity intrusion due to sea-level and temperature rise, as reported in the National Climate Vulnerability Index 2018. This research uses the methodology proposed by ICLEI South Asia’s Climate Resilient Cities Action Plan and accesses different urban actors’ adaptive capacity for contributing to enhancing climate resilience based on three broad characteristics: the capacity to organize and respond, availability of resources and access to information. The cumulative scores of these characteristics aid in determining the climate adaptive capacity of each urban actor. Findings The identified 53 actors are grouped into four categories: government (local and national); international/local NGOs, CBOs and associations; community representatives and private sectors and groups and individuals. The group of NGOs, CBOs and associations has a higher overall adaptive potential than all other actor groups, according to the study. When it comes to practicing adaptive capacity, government institutions are in the second-highest position. But, the Khulna development authority, the government agency that is in charge of overseeing all forms of urban development, scored poorly on all fragile urban systems. However, the performance of the fourth group of urban actors is very subpar when it comes to adapting to climatic stress, which emphasizes the need for focused interventions. Research limitations/implications Variations in adaptive capacities to climate change across different actors are particularly useful for targeting actors with lower levels of climate adaptive capacities in Mongla town. Originality/value This paper particularly addresses the research gap in assessing the adapting capacity of urban actors in Mongla port-town. Policymakers and practitioners can create and carry out targeted interventions that address the particular needs and concerns of vulnerable actors by making use of the insights obtained from this kind of study, thereby assisting in the development of climate resilience in any urban area.

Long range transport of South and East Asian anthropogenic aerosols counteracting Arctic warming

The large-scale convection during the Asian summer monsoon plays an important role in the rapid transport of boundary layer aerosols into the Asian summer monsoon anticyclone. Here, using the state-of-the-art ECHAM6–HAMMOZ aerosol-chemistry-climate model, we show that these aerosols are further transported to the Arctic along isentropic surfaces by the Brewer-Dobson-Circulation (BDC) during the monsoon season. Our model simulations show that East and South Asian anthropogenic emissions contribute significantly to the aerosol transported to the Arctic, which causes a higher negative net aerosol radiative forcing at the surface (dimming) of −0.09 ± 0.02 Wm−2 and −0.07 ± 0.02 Wm−2, respectively. Over the Arctic, the East Asian anthropogenic aerosols that include large amounts of sulfate cause a seasonal mean net radiative forcing at the top of the atmosphere (TOA) of −0.003 ± 0.001Wm−2 and a surface cooling of −0.56 K while the black carbon dominated aerosol from South Asia shows a positive TOA forcing of +0.004 ± 0.001Wm−2 with an only minor surface cooling of −0.043 K. Overall, the long-range transport of South Asian aerosols results in a notably warming throughout the atmospheric column but minimal temperature response at the Arctic surface. Conversely, East Asian aerosols cool the troposphere and heat the lower stratosphere in the Arctic. The Asian aerosol thus plays an ambivalent role, with the East Asian sources in particular having the potential to counteract the rapid rise in Arctic temperatures and the associated melting of snow and ice.

Correction: Experimental and Numerical Investigations of the Effect of Curing Conditions on the Temperature Rise of Concrete

Correction: Experimental and Numerical Investigations of the Effect of Curing Conditions on the Temperature Rise of Concrete

Thermal management and switching performance of β-Ga2O3 vertical FinFET with diamond-gate structure

Abstract In this paper, a beta-phase gallium oxide (β-Ga2O3) vertical FinFET with diamond-gate has been studied by Silvaco-ATLAS simulation. The diamond-gate structure achieves adjustable pin (p-insulator-n) junction owing to the diamond-SiO2-Ga2O3 heterostructure. This design also enhances heat dissipation by virtue of the high thermal conductivity of the diamond. Compared to conventional FinFETs, the diamond-gate FinFET (DG-FinFET) reduces the static operating temperature rise by around 17.30%. Additionally, due to its greater heat dissipation capacity, DG-FinFETs provide an 5.84% increase in current density at 1 kA/cm2 current density level. The structural changes in the diamond-gate also result in a significant reduction in the gate-source capacitance (CGS). At 1 MHz operating frequency and the same gate voltage, DG-FinFETs have 69.29% less gate-source charge (QGS), 70.80% less charge/discharge delay time, 73.70% less switching loss, and 57.15% less conduction loss. Overall, the simulation and analysis presented in this work indicate a promising advancement of the DG-FinFET structure in high-power and rapid switching applications.

Liquid‐Metal‐Loaded Hydrogel with Antibacterial Effect and Sustained Release of Growth Factor for Wound Healing

AbstractMultifunctional medical hydrogels play an important role in wound healing because of their excellent biocompatibility, convenient operation, and drug release capacity. So far, many efforts have been exploited to developing new‐generation hydrogels with distinctive capabilities in promoting wound healing. Herein, the liquid‐metal (LM)‐loaded hydrogels are reported with antibacterial effect under an 808 nm near‐infrared laser irradiation for wound healing therapeutic strategies. The addition of LM droplets enables the hydrogel to control the temperature rise and plays an antibacterial effect with the release of gallium3+ under laser irradiation. Benefiting from the porous network structure of hydrogels, the encapsulated growth factors can be released stably at the wound site. Under the synergistic effect of LM and growth factors in the wound tissue, the hydrogel displays antibacterial features and promotes the regeneration of epithelial tissue and neovascularization, thereby further accelerating wound healing. This hydrogel has proven biosafety and low toxicity in vitro and in vivo. With these advantages, such hydrogel is a promising candidate to be developed as a new medical product for future clinical medicine.

Electromagnetic–thermal–mass transport triple hybrid model for energy-efficient hydrogen release from metal particles by induction heating

Hydrogen storage in metals is anticipated to be a highly promising technical approach for managing hydrogen in diverse energy applications, emphasizing the need to establish efficient operating conditions. In this study, we developed a numerical model that can simultaneously calculate hydrogen and heat transport combined with electromagnetic induction heating of metal particles. Using the developed numerical simulator, we investigated the behavior of the hydrogen release process from the hydrogen-absorbing metal and proposed important indicators for the operation. The fractions of the electromagnetic energy absorbed by the metal particle used for the hydrogen release, sensible heat, interfacial heat conduction, and thermal radiation were systematically evaluated. Considering the trade-off between temperature rise and the hydrogen concentration gradient, an optimal diameter of metal particles existed for the maximum hydrogen release rate. Similarly, the trade-off between temperature rise and energy consumption revealed an optimal electromagnetic power density for the heat utilization fraction for hydrogen release. Our electromagnetic–thermal–mass transport triple hybrid model constitutes a useful numerical simulator for the design of energy-efficient hydrogen storage systems.

Effect on combustion performance and emission behavior of diesel engine fueled with hybrid biodiesel produced from a novel ternary oil mixture incorporated with nano additive

ABSTRACT Global energy demand has been above 80% fossil fuels for decades, creating a greater and more complicated energy crisis. Biodiesel is a great alternate energy source for future energy demand. Producing biodiesel from a mixture of waste and non-edible oils may be a practical solution to address the growing global need of biodiesel. In this study, hybrid biodiesel is produced from a ternary oil mixture of Waste cooking oil, Ricinus communis oil, and Melia azedarach oil. The hybrid biodiesel blends are prepared by 10% blending (HB10), 20% blending (HB20) and 30% blending (HB30) and 30ppm multiwall carbon nanotube has been added in the blended fuel through sonicating process. At steady 1500rmp and variable load (0–100%), the engine behavior has been examined. The results show that the hybrid biodiesel blend (HB10) with 30ppm MWCNT has shown highest cylinder pressure of 70.9 bar, maximum mean gas temperature 1467.56°C. The engine shows 34.08% rise in net heat release and 9.13% rise in exhaust gas temperature as compare to diesel. The maximum rise in break thermal efficiency of 19.74% and minimum reduction in break specific fuel consumption of 13.79% is noticed in comparison to B00. The highest reduction of HC emission is found as 20.83% for HB20MWCNT30 and 19.34% for HB30MWCNT30 as compare to B00. The inclusion of multiwall carbon nanotube in hybrid biodiesel reduces the HC, CO, NOx and smoke emission and increases CO2 emission as compare to respective hybrid biodiesel blend and diesel. The hybrid biodiesel-diesel blend, with multiwall carbon nanotube can be utilized efficiently in diesel engine with improved overall engine behavior.

Full-Scale Modeling and FBGs Experimental Measurements for Thermal Analysis of Converter Transformer

As the imbalance between power demand and load capacity in electrical systems becomes increasingly severe, investigating the temperature variations in transformers under different load stresses is crucial for ensuring their safe operation. The thermal analysis of converter transformers poses challenges due to the complexity of model construction. This paper develops a full-scale model of a converter transformer using a multi-core high-performance computer and explores its thermal state at 80%, 100%, and 120% loading ratios using the COUPLED iteration method. Additionally, to validate the simulation model, 24 FBGs are installed in the experimental transformer to record the temperature data. The results indicate a general upward trend in winding the temperature from bottom to top. However, an internal temperature rise followed by a decrease is observed within certain sections. Moreover, as the loading ratio increases, both the peak temperature and temperature differential of the transformer windings rise, reaching a peak temperature of 107.9 °C at a 120% loading ratio. The maximum discrepancy between the simulation and experimental results does not exceed 3.5%, providing effective guidance for the transformer design and operational maintenance.

Design, Simulation and Optimization of a Novel Transpired Tubular Solar Air Heater

In this paper, a novel tubular solar air heater is introduced. In this air heater, the hot boundary layer is drawn into the absorber tube and can provide thermal energy at moderate temperatures. Several different cases were simulated and a correlation was proposed to predict the collector’s effectiveness as a function Rayleigh number and Reynolds number. An equation was derived to find the effectiveness of this collector. Finally, a real case was studied with non-uniform solar flux distribution, as well as radiation heat loss. Good agreement was found between the results and those derived by the proposed analytical method. For different suction values, the first-law and the second-law efficiencies were calculated. Based on the exergy analysis, exergy destruction in absorption is the dominant factor that is unavoidable in low-temperature collectors. It was shown that there is an optimum suction value at which the second-law efficiency is maximized. At the optimum point, temperature rise can reach 54 K, which is hardly possible with a flat plate collector. Based on the exergy analysis, the relation between tube wall temperature and air outlet temperature in their dimensionless forms at the optimum working condition was derived, and it was shown that effectiveness at the optimum working condition is around 0.5. This means that the air temperature rise shall be half of the temperature difference between collector wall and the ambient temperatures. A high outlet temperature besides the low cost of construction and maintenance are the main advantages of this air heater. With such a high temperature rise, this type of collector can increase the use of solar energy in domestic applications.

A dusty rain falls on the nova V959 Monocerotis

Abstract We present archival and ground-based infrared observations of the γ-ray-emitting nova V959 Mon, covering the period 100–4205 days after the 2012 eruption. We use these data to determine that the secondary in the nova system is a G5 main sequence star. Data from the NEOWISE survey reveal a significant increase in the emission at 3.4$\, \mu$m and 4.6$\, \mu$m at late (≳ 600 days) times, which we interpret as emission by dust. Other interpretations are considered but cannot be reconciled with the data. The presence of such late dust emission, and in particular its variation with time, are unprecedented in the context of novae. The behaviour of the dust emission suggests a qualitative interpretation in which ejecta from the 2012 eruption encounter denser pre-eruption circumbinary material, giving rise to Rayleigh-Taylor instabilities that cause clumps of dust-bearing material to fall back towards the central binary, the dust undergoing destruction by chemisputtering as it does so. The observed rise in the dust temperature, the decline in the nova-dust distance and in the dust mass, are consistent with this interpretation. Not all novae are expected to show this behaviour, but inspection of resources such as NEOWISE might reveal other novae post-eruption that do.

Role of supplementary cementiteous materials in mitigating heat of hydration in mass concrete elements

Concrete’s heat of hydration can cause wide restraint cracks, delayed ettringite formation and low strength. The heat of hydration in concrete poses significant challenges in the construction industry particularly in mass concrete elements. Addressing these challenges, the utilization of supplementary cementitious materials (SCMs) such as fly ash (FA) and ground granulated blast furnace slag (GBFS) in concrete has been extensively studied for their individual contributions in modifying the heat of hydration. However, the comparative effectiveness of FA and GBFS, as well as the implications of their combined use in a ternary blend mix, remain underexplored. This study aims to bridge this gap by investigating the heat evolution profiles of concrete blends incorporating varying proportions of FA, GBFS, and general Portland cement (GPC). Through a series of semi-adiabatic tests, the study evaluates the hydration kinetics, maximum temperature rise, and time delay to peak temperature for binary and ternary mixes. The findings suggest that while individual SCMs like FA and GBFS offer distinct thermal benefits, their combined use in a ternary blend presents a synergistic effect, optimizing heat management in concrete. In essence, this study not only underlines the potential of ternary blends in enhancing concrete's thermal performance but also emphasizes their role in promoting sustainable and resilient construction practices.

Thermal Insulation of “akassa” Hot Preservation Baskets Using Cow Dung Coatings

The use of eco-materials for thermal insulation is becoming more and more recommended compared with synthetic materials. They have the advantage of being biodegradable and sometimes less expensive. To this end, the use of packaging with the function of hot preservatives but made from local and biodegradable materials is a very interesting alternative to synthetic enclosures. This work involved formulating eco-materials made from cow dung coatings and a mixture of cow dung coatings with a framework of fibres extracted from the stalks of oil palm leaves. In addition, to monitor the temperature rise in the various eco-materials manufactured and characterise them using the hot ribbon method to determine their effusivity and thermal conductivity. The pair of materials exposed to heating showed a gradual rise in temperature within the materials when the resistor was energised. A slightly faster rise was observed in the first fifty minutes. The results obtained indicate that the cow dung has a higher effusivity (E = 517.32 J.m<sup>-2</sup>. °C<sup>-1</sup>. s<sup>-1/2</sup>) than its composite (E = 501.20 J.m<sup>-2</sup>. °C<sup>-1</sup>. s<sup>-1/2</sup>). The thermal conductivity values obtained indicate that the cow dung has a higher thermal conductivity (λ'=0.19 W.m^(-1).K^(-1)) than that of the composite structure (λ=0.15 W.m^(-1).K^(-1)). From the above, the presence of the fibre frame has the effect of reducing thermal conductivity because it absorbs more energy. The materials produced therefore have proven insulating properties, which are improved when the framework is made from fibres extracted from the stalks of oil palm leaves. Using oil palm fibres in combination with cow dung as eco-materials for thermal insulation is an excellent alternative to synthetic insulation.

Predicting wheat flour quality for making Japanese sponge cake using flour pasting properties as measured by the Rapid Visco Analyzer

AbstractBackground and ObjectivesThe objective of this study was to evaluate a series of Rapid Visco Analyzer (RVA) methods for their ability to produce results that were predictive of Japanese sponge cake (JSC) quality. Two solvents (water and 50% [w/w] sucrose in water) and two temperature profiles [Standard 1 (STD 1) and an internal cake temperature profile] were selected to run across a diverse set of flour samples from two crop years that possessed variable bake performance. The results were analyzed for predictive outcomes for JSC prepared using a mechanical fold method.FindingsThe solvent retention capacity (SRC) results did not show any significant trends with JSC quality. The RVA results from both profiles using water as the solvent did not show a significant correlation with JSC quality while the 50% (w/w) sucrose solvent was significantly correlated (p ≤ .01). The STD 1 and internal cake temperature profile batter pasting viscosity (BPV) using the sucrose solvent showed significant (p ≤ .01) correlations with mechanical folded JSC volume (r = .97), firmness (r = −.88), and overall score (r = .85).ConclusionsThe RVA BPV results showed that a 50% sucrose solvent could more accurately be used to predict and screen for JSC quality outcomes. Both RVA profiles could be used with a sucrose solvent to predict JSC quality. JSC volume and overall score showed significant positive correlations with BPV while firmness had a significant negative correlation.Significance and NoveltyThis research identified two RVA profiles that when paired with a 50% (w/w) sucrose solvent could be used to screen for JSC quality using less flour and taking less time than a bake test. This test could potentially assist breeders and millers in quicky screening flours for efficient decision making. This is the first time an RVA temperature profile that mimics the internal rise in temperature for a JSC during baking has been used to predict JSC quality. In addition, the STD 1 profile using the 50% (w/w) sucrose solvent has not been previously used to predict JSC quality.

Seasonal Scale Climatic Factors on Grassland Phenology in Arid and Semi-Arid Zones

Influenced by climate change, significant alterations in vegetation phenology have been observed globally. Grassland phenology is highly sensitive to climate change. However, research on the variations in grassland phenology and its responses to seasonal climatic changes in arid and semi-arid regions remains scarce. This study, utilizing Solar-Induced Chlorophyll Fluorescence (SIF) data, meteorological station data, and grassland type data, employs trend analysis and time series analysis to explore the trends of seasonal climatic variability and the sensitivity response of grassland phenology in Xinjiang to seasonal climates. The findings reveal the following: (1) The region experiences more pronounced warming in winter and spring than in summer and autumn, with ground temperature increments outpacing those of air temperatures. The summer season registers the peak in precipitation volume and rate of increase, where mountainous zones accrue more rainfall compared to basins and plains. The distribution of sunshine duration is characterized by higher values in eastern areas than in the west and more in the plains than in mountainous regions, potentially due to escalating cloudiness, which has contributed to a diminishing trend in sunshine hours across Xinjiang over the past 20 years. (2) Over the past two decades, the perennial greening phase of Xinjiang grasslands has predominantly occurred in early May, showing an overall trend of occurring earlier by approximately 5.47 days per decade, while the yellowing phase mainly occurs at the end of September and the beginning of October, demonstrating a delaying trend (6.61 days/decade). The average length of the growing season is 145 days, generally showing a slightly increasing trend (11.97 days/decade). (3) In spring, the rise in air and ground temperatures, along with increased sunshine duration, all promote grassland growth, leading to an earlier greening phase. Conversely, in autumn, increases in air temperature, ground temperature, and sunshine duration can inhibit grassland growth, resulting in an earlier yellowing phase. Increased precipitation in summer and autumn can delay the yellowing phase and extend the length of the grassland growing season. This research provides new insights into the factors influencing large-scale grassland phenology and offers references for grassland adaptation to future climate changes.

Stretch-forming characteristics of austenitic material stainless steel 304 at hot working temperatures

Abstract The need for sheet metal forming using highly resistant materials such as titanium alloys and stainless steel has increased recently. These materials possess elevated mean flow stress values, which make them difficult to draw at room temperature. To achieve a homogeneous distribution of strain in the stretched component, reduce the load required for plastic deformation, and greatly improve material formability, hot forming is helpful. The goal of the current study is to conduct stretch-forming experiments to investigate the forming characteristics of Austenitic material Stainless Steel (ASS) 304 at Hot working temperatures. Stretch forming experiments have been conducted on the Servo electrical sheet press test machine at 650 and 800°C. The formability has been estimated by constructing a Fracture forming diagram (FFLD), limiting the height of the dome (LDH) and the distribution of the strain of stretched cups. It has been discovered that the limit of forming bounds rises with the temperature reaching 800°C, while the DSA effect causes the necking region – the area between the safe and fracture limits ‒ to decrease with additional temperature rise from 800 to 900°C. Within the experimental limitations, it has been considered that the Hot forming of ASS 304 at 650°C gives the highest strain forming limits with a uniform strain distribution in the stretched cups. From the Formability limit diagram, dome height, and strain distribution, it can be observed that ASS 304 has good limiting strain up to 800°C with lower load application.