Using satellite-derived land surface temperatures to clarify the spatiotemporal warming trends of the Alborz Mountains in northern Iran

The Alborz Mountains are some of the highest in Iran,and they play an important role in controlling the climate of the country’s northern regions.The land surface temperature(LST)is an important variable that affects the ecosystem of this area.This study investigated the spatiotemporal changes and trends of the nighttime LST in the western region of the Central Alborz Mountains at elevations of 1500-4000 m above sea level.MODIS data were extracted for the period of 2000-2021,and the Mann-Kendall nonparametric test was applied to evaluating the changes in the LST.The results indicated a significant increasing trend for the monthly average LST in May-August along the southern aspect.Both the northern and southern aspects showed decreasing trends for the monthly average LST in October,November,and March and an increasing trend in other months.At all elevations,the average decadal change in the monthly average LST was more severe along the southern aspect(0.60°C)than along the northern aspect(0.37°C).The LST difference between the northern and southern aspects decreased in the cold months but increased in the hot months.At the same elevation,the difference in the lapse rate between the northern and southern aspects was greater in the hot months than in the cold months.With increasing elevation,the lapse rate between the northern and southern aspects disappeared.Climate change was concluded to greatly decrease the difference in LST at different elevations for April-July.

Development of a RBFNN prediction model for carrot quality based on meteorological temperatures at vegetable stations

To evaluate and predict the quality of carrots during logistics process in North China under extreme temperature conditions,quality indicator changes of carrots were investigated,and temperature-coupled quality prediction models were developed.Seven temperatures were selected from meteorological temperature data by cluster analysis to simulate the changes in extreme temperatures during the short-term transportation of carrots.No carrots rotted during the 48h storage period.Under both isothermal and nonisothermal conditions,weight loss andΔE increased while the firmness and sensory evaluation(SE)decreased.The RBFNN performed better than the Arrhenius model in predicting weight loss andΔE,with R^(2)>0.97,MSE<0.009 and relative errors within±18%.The results of the predictive confidence level and standardized residual indicated the good performance of the RBFNN model.The temperature-coupled prediction models of RBFNN were promising candidates for predicting the quality of vegetable products and therefore reducing economic loss of vegetable industry.

Climate warming is significantly influenced by rising summer maximum temperatures: insights from tree-ring evidence of the Western Tianshan Mountains, China

As one of the regions most affected by global cli-mate warming,the Tianshan mountains has experienced sev-eral ecological crises,including retreating glaciers and water deficits.Climate warming in these mountains is considered mainly to be caused by increases in minimum temperatures and winter temperatures,while the influence of maximum temperatures is unclear.In this study,a 300-year tree-ring chronology developed from the Western Tianshan Moun-tains was used to reconstruct the summer(June-August)maximum temperature(T_(max6-8))variations from 1718 to 2017.The reconstruction explained 53.1% of the variance in the observed T_(max6-8).Over the past 300 years,the T_(max6-8)reconstruction showed clear interannual and decadal vari-abilities.There was a significant warming trend(0.18°C/decade)after the 1950s,which was close to the increasing rates of the minimum and mean temperatures.The increase in maximum temperature was also present over the whole Tianshan mountains and its impact on climate warming has increased.The T_(max6-8) variations in the Western Tianshan mountains were influenced by frequent volcanic eruptions combined with the influence of solar activity and the sum-mer North Atlantic Oscillation.This study reveals that cli-mate warming is significantly influenced by the increase in maximum temperatures and clarifies possible driving mech-anisms of temperature variations in the Western Tianshan mountains which should aid climate predictions.

Climate warming is significantly influenced by rising summer maximum temperatures:insights from tree-ring evidence of the Western Tianshan Mountains,China

As one of the regions most affected by global climate warming,the Tianshan mountains has experienced several ecological crises,including retreating glaciers and water deficits.Climate warming in these mountains is considered mainly to be caused by increases in minimum temperatures and winter temperatures,while the influence of maximum temperatures is unclear.In this study,a 300-year tree-ring chronology developed from the Western Tianshan Mountains was used to reconstruct the summer(June-August)maximum temperature(Tmax6-8) variations from 1718 to2017.The reconstruction explained 53.1% of the variance in the observed Tmax6-8.Over the past 300 years,the Tmax6-8reconstruction showed clear interannual and decadal variabilities.There was a significant warming trend(0.18 ℃/decade) after the 1950s,which was close to the increasing rates of the minimum and mean temperatures.The increase in maximum temperature was also present over the whole Tianshan mountains and its impact on climate warming has increased.The Tmax6-8variations in the Western Tianshan mountains were influenced by frequent volcanic eruptions combined with the influence of solar activity and the summer North Atlantic Oscillation.This study reveals that climate warming is significantly influenced by the increase in maximum temperatures and clarifies possible driving mechanisms of temperature variations in the Western Tianshan mountains which should aid climate predictions.

Predictive modeling of critical temperatures in magnesium compounds using transfer learning

This study presents a transfer learning approach for discovering potential Mg-based superconductors utilizing a comprehensive target dataset.Initially,a large source dataset(Bandgap dataset)comprising approximately∼75k compounds is utilized for pretraining,followed by fine-tuning with a smaller Critical Temperature(T_(c))dataset containing∼300 compounds.Comparatively,there is a significant improvement in the performance of the transfer learning model over the traditional deep learning(DL)model in predicting Tc.Subsequently,the transfer learning model is applied to predict the properties of approximately 150k compounds.Predictions are validated computationally using density functional theory(DFT)calculations based on lattice dynamics-related theory.Moreover,to demonstrate the extended predictive capability of the transfer learning model for new materials,a pool of virtual compounds derived from prototype crystal structures from the Materials Project(MP)database is generated.T_(c) predictions are obtained for∼3600 virtual compounds,which underwent screening for electroneutrality and thermodynamic stability.An Extra Trees-based model is trained to utilize E_(hull)values to obtain thermodynamically stable materials,employing a dataset containing Ehull values for approximately 150k materials for training.Materials with Ehull values exceeding 5 meV/atom were filtered out,resulting in a refined list of potential Mg-based superconductors.This study showcases the effectiveness of transfer learning in predicting superconducting properties and highlights its potential for accelerating the discovery of Mg-based materials in the field of superconductivity.

Dependence of impact regime boundaries on the initial temperatures of projectiles and targets

Towards higher impact velocities,ballistic events are increasingly determined by the material temperatures.Related effects might range from moderate thermal softening to full phase transition.In particular,it is of great interest to quantify the conditions for incipient or full melting of metals during impact interactions,which result in a transition from still strength-affected to hydrodynamic material behavior.In this work,we investigate to which extent the respective melting thresholds are also dependent on the initial,and generally elevated,temperatures of projectiles and targets before impact.This is studied through the application of a model developed recently by the authors to characterize the transition regime between high-velocity and hypervelocity impact,for which the melting thresholds of materials were used as the defining quantities.The obtained results are expected to be of general interest for ballistic application cases where projectiles or targets are preheated.Such conditions might result,for example,from aerodynamic forces acting onto a projectile during atmospheric flight,explosive shapedcharge-jet formation or armor exposure to environmental conditions.The performed analyses also broaden the scientific understanding of the relevance of temperature in penetration events,generally known since the 1960s,but often not considered thoroughly in impact studies.

Higher Grain-Filling Rate in Inferior Spikelets of Tolerant Rice Genotype Offset Grain Yield Loss under Post-Anthesis High Night Temperatures

Increased nighttime respiratory losses decrease the amount of photoassimilates available for plant growth and yield. We hypothesized that the increased respiratory carbon loss under high night temperatures(HNT) could be compensated for by increased photosynthesis during the day following HNT exposure. Two rice genotypes, Vandana(HNT-sensitive) and Nagina 22(HNT-tolerant), were exposed to HNT(4 ℃ above the control) from flowering to physiological maturity. They were assessed for alterations in the carbon balance of the source(flag leaf) and its subsequent impact on grain filling dynamics and the quality of spatially differentiated sinks(superior and inferior spikelets). Both genotypes exhibited significantly higher night respiration rates. However, only Nagina 22 compensated for the high respiration rates with an increased photosynthetic rate, resulting in a steady production of total dry matter under HNT. Nagina 22 also recorded a higher grain-filling rate, particularly at 5 and 10 d after flowering, with 1.5- and 4.0-fold increases in the translocation of ^(14)C sugars to the superior and inferior spikelets, respectively. The ratio of photosynthetic rate to respiratory rate on a leaf area basis was negatively correlated with spikelet sterility, resulting in a higher filled spikelet number and grain weight per plant, particularly for inferior grains in Nagina 22. Grain quality parameters such as head rice recovery, high-density grains, and gelatinization temperature were maintained in Nagina 22. An increase in the rheological properties of rice flour starch in Nagina 22 under HNT indicated the stability of starch and its ability to reorganize during the cooling process of product formation. Thus, our study showed that sink adjustments between superior and inferior spikelets favored the growth of inferior spikelets, which helped to offset the reduction in grain weight under HNT in the tolerant genotype Nagina 22.

Contribution of Surface Waves to Sea Surface Temperatures in the Arctic Ocean

The aim of our study was to examine the contribution of surface waves from WAVEWATCH-III(WW3)to the variation in sea surface temperature(SST)in the Arctic Ocean.The simulated significant wave height(SWH)were validated against the products from Haiyang-2B(HY-2B)in 2021,obtaining a root mean squared error(RMSE)of 0.45 with a correlation of 0.96 and scatter index of 0.18.The wave-induced effects,i.e.,wave breaking and mixing induced by nonbearing waves resulting in changes in radiation stress and Stokes drift,were calculated from WW3,ERA-5 wind,SST,and salinity data from the National Centers for Environmental Prediction and were taken as forcing fields in the Stony Brook Parallel Ocean Model.The results showed that an RMSE of 0.81℃ with wave-induced effects was less than the RMSE of 1.11℃ achieved without the wave term compared with the simulated SST with the measurements from Argos.Considering the four wave effects and sea ice freezing,the SST in the Arctic Ocean decreased by up to 1℃ in winter.Regression analysis revealed that the SWH was linear in SST(values without subtraction of waves)in summer and autumn,but this behavior was not observed in spring or winter due to the presence of sea ice.The interannual variation also presented a negative relationship between the difference in SST and SWH.

Improving tree health assessment accuracy at low temperatures:considering the effect of trunk ice content on electrical resistance and stress wave tomography

Accurate decay detection and health assessment of trees at low temperatures is an important issue for forest management and ecology in cold areas.Low temperature ice formation on tree health assessment is unknown.Because electric resistance tomography and stress wave tomography are two widely used methods for the detection of tree decay,this study investigated the effect of ice content on trunk electrical resistance and stress wave velocity to improve tree health assessment accuracy.Moisture content,trunk electrical resistance and stress wave velocity using time domain reflectometry were carried out on Larix gmelinii and Populus simonii.Ice content is based on moisture content data.The ice content of both species showed a trend of increasing and then decreasing.This was opposite with ambient temperatures.With the decrease of temperatures,daily average ice content increased,but the range narrowed gradually and both electrical resistance and stress wave velocity increased.Both increased rapidly near 0℃,mainly caused by ice formation(phase change and freezing of free water)in live trees.In addition,both are positively correlated with ice content.The results suggest that ice content should be considered for improving the accuracy of tree decay detection and health evaluation using electric resistance tomography and stress wave velocity methods under low temperatures.

Mesopause temperatures and relative densities at midlatitudes observed by the Mengcheng meteor radar

The atmospheric temperatures and densities in the mesosphere and lower thermosphere(MLT)region are essential for studying the dynamics and climate of the middle and upper atmosphere.In this study,we present more than 9 years of mesopause temperatures and relative densities estimated by using ambipolar diffusion coefficient measurements observed by the Mengcheng meteor radar(33.4°N,116.5°E).The intercomparison between the meteor radar and Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Sounding of the Atmosphere by Broadband Emission Radiometry(TIMED/SABER)and Earth Observing System(EOS)Aura/Microwave Limb Sounder(MLS)observations indicates that the meteor radar temperatures and densities agree well with the simultaneous satellite measurements.Annual variations dominate the mesopause temperatures,with the maximum during winter and the minimum during summer.The mesopause relative densities also show annual variations,with strong maxima near the spring equinox and weak maxima before the winter solstice,and with a minimum during summer.In addition,the mesopause density exhibits a structure similar to that of the zonal wind:as the zonal wind flows eastward(westward),the mesopause density decreases(increases).At the same time,the meridional wind shows a structure similar to that of the mesopause temperature:as the meridional wind shows northward(southward)enhancements,the mesopause temperature increases(decreases).Simultaneous horizontal wind,temperature,and density observations provide multiple mesospheric parameters for investigating mesospheric dynamics and thermodynamic processes and have the potential to improve widely used empirical atmospheric models.

Microstructural characteristics and low-cycle fatigue properties of AZ91 and AZ91-Ca-Y alloys extruded at different temperatures

The commercial AZ91 alloy and nonflammable SEN9(AZ91-0.3Ca-0.2Y,wt%)alloy are extruded at 300°C and 400°C.Their microstructure,tensile and compressive properties,and low-cycle fatigue(LCF)properties are investigated,with particular focus on the influence of the extrusion temperature.In the AZ91 and SEN9 materials extruded at 300°C(300-materials),numerous fine Mg_(17)Al_(12)particles are inhomogeneously distributed owing to localized dynamic precipitation during extrusion,unlike those extruded at 400°C(400-materials).These fine particles suppress the coarsening of recrystallized grains,decreasing the average grain size of 300-materials.Although the four extruded materials have considerably different microstructures,the difference in their tensile yield strengths is insignificant because strong grain-boundary hardening and precipitation hardening effects in 300-materials are offset almost completely by a strong texture hardening effect in 400-materials.However,owing to their finer grains and weaker texture,300-materials have higher compressive yield strengths than400-materials.During the LCF tests,{10-12}twinning is activated at lower stresses in 400-materials than in 300-materials.Because the fatigue damage accumulated per cycle is smaller in 400-materials,they have longer fatigue lives than those of 300-materials.A fatigue life prediction model for the investigated materials is established on the basis of the relationship between the total strain energy density(ΔW_(t))and the number of cycles to fatigue failure(N_(f)),and it is expressed through a simple equation(ΔW_(t)=10·N_(f)-0.59).This model enables fatigue life prediction of both the investigated alloys regardless of the extrusion temperature and strain amplitude.

Emergency department rectal temperatures in over 10 years:A retrospective observational study

BACKGROUND:Fever in patients can provide an important clue to the etiology of a patient's symptoms.Non-invasive temperature sites(oral,axillary,temporal) may be insensitive due to a variety of factors.This has not been well studied in adult emergency department patients.To determine whether emergency department triage temperatures detected fever adequately when compared to a rectal temperature.METHODS:A retrospective chart review was made of 27 130 adult patients in a high volume,urban emergency department over an eight-year period who received first a non-rectal triage temperature and then a subsequent rectal temperature.RESULTS:The mean difference in temperatures between the initial temperature and the rectal temperature was 1.3 °F(P<0.001),with 25.9%of the patients having higher rectal temperatures >2°F,and 5.0%having higher rectal temperatures >4 °F.The mean difference among the patients who received oral,axillary,and temporal temperatures was 1.2 °F(PO.001),1.8 °F(PO.001),and 1.2 °F(P<0.001) respectively.About 18.1%of the patients were initially afebrile and found to be febrile by rectal temperature,with an average difference of 2.5 °F(P<0.001).These patients had a higher rate of admission(61.4%,P<0.005),and were more likely to be admitted to the hospital for a higher level of care,such as an intensive care unit,when compared with the full cohort(12.5%vs.5.8%,P<0.005).CONCLUSIONS:There are significant differences between rectal temperatures and noninvasive triage temperatures in this emergency department cohort.In almost one in five patients,fever was missed by triage temperature.

Physiological Responses of Clam(Ruditapes philippinarum)to Transport Modes with Different Temperatures

Given the increased circulation time after fishing,a series of changes take place in live clams,leading to a deterioration in quality even after death.Thus,in this study,we aimed to explore the optimal mode of transportation of clams.The container for holding clams was reformed,and a water circulation temperature control system was established.The physiological responses of clams during anhydrous and watery transportation at two temperatures(4 and 15℃)were investigated based on the aforementioned system.When comparing the transportation patterns after 3 d of transport,a higher survival rate was observed at 4℃(97%)than at 15℃(63%)in the anhydrous transportation groups and a lower survival rate was observed at 4℃(93%)than at 15℃(99%)in the watery transportation groups.In addition,the glycogen content,condition index(CI),and adenylate energy charge(A.E.C)value were higher at4℃((40.87±0.99)mg g^(-1),13.71%±0.50%and 57.45%±1.60%)than at 15℃((30.54±0.81)mg g^(-1),9.09%±0.30%and 43.12%±1.65%)in the anhydrous transportation groups.In the watery transportation groups,a lower glycogen content,CI,and A.E.C.value were observed at 4℃((33.78±0.84)mg g^(-1),9.78%±0.50%and 64.65%±1.25%)than at 15℃((41.53±0.93)mg g^(-1),12.72%±0.83%and 71.58%±1.27%).Results from this study show that anhydrous transportation(4℃)is the optimal transport condition for clams to maintain a high quality and good physiological conditions.Thus,this study will be particularly useful for establishing shellfish transportation systems.

An investigation on failure behavior of semi-flexible composite mixture at different temperatures

Semi-flexible composite mixture(SFCM)is a kind of pavement material formed by pouring cement-based grout material into a porous asphalt mixture with air voids from 20%to 30%.SFCM is widely used for its outstanding anti-rutting performance.Its mechanical performance is complicated due to its heterogeneity and interlocking structure.According to the present study,asphalt deforms at different temperatures,whereas cement-based grout has no similar characteristics.Rare research focuses on the temperature-based performance of SFCM.Therefore,the study was on the thermal performance of SFCM by seven open-graded asphalt mixture skeletons with different porosities and two types of grouts with early strength(ES)and high strength(HS).The test temperatures ranged from 10℃to 60℃.The mechanical investigation was performed using the semi-circular-bending(SCB)and beam bending tests.The strain sensor was used for analyzing the thermal performance of SFCM.The results show that the temperature significantly affected the SFCM's performance.The porosity was selected for three sections based on the trend of fracture energy(Gf)curves at 25℃.The turning points were the porosity values of 20%and 26%.The initiation slope during elastic deformation increases with the porosity increase.This trend was more evident at intermediate temperature.The shrink strain of SFCM was lower than that of the usual asphalt mixture(AC).The thermal stress of the SFCM filled with HS(HS-SFCM)was higher than that of the SFCM filled with ES(ES-SFCM)at 10℃.Moreover,the thermal failure characteristics of SFCM were influenced by porosity.

Normalized fatigue properties of asphalt mixture at various temperatures

This study normalized the mixture's fatigue behavior at various temperatures,and the strength and fatigue tests of the mixture were conducted.The stress state of the asphalt mixture includes direct tensile,uniaxial compression,and indirect tensile.The Desai yield surface and fatigue path were proposed.And a normalized fatigue characteristics model of the mixture was established.The following conclusions were obtained.With the increases in the loading rate,the strength of the asphalt mixture increased.As the temperature increases,the strength of the mixture is reduced.At various temperatures and rates,the strength forms a closed curved surface.The Desai strength yield surface was established,which forms a closed curved surface.When the loading rate and temperature are below a certain critical line,the asphalt mixture will not undergo strength damage.At a fixed stress state,the fatigue damage path of the mixture was determined.The stress ratio was determined considering the influence of the loading rate.In this way,a normalized model can be described to express the asphalt mixture fatigue properties at various temperatures and stress levels.For the asphalt mixture in an indirect tensile state,the normalized fatigue equation parameter is 4.09.This model is more suitable for reflecting the viscous-elastic behavior of the mixtures than the fatigue equation determined by the notional stress ratio.

Lithium-Sulfur Batteries at Extreme Temperatures:Challenges,Strategies and Prospects

High-energy-density-batteries working at a wide-temperature range are urgently required in many performance-critical areas.Lithium-sulfur batteries(LSB)are promising high-energy-density batteries that have the potential to maintain high performance at extreme temperatures.However,some problems like severe shuttling and safety issues at high temperatures or sluggish reaction kinetics and charge-transfer process at low temperatures decrease the performance and hinder their practical uses in extreme temperature conditions.Therefore,broadening the working temperature of LSB with stable electrochemical performance becomes a crucial topic.In this paper,the key stumbling blocks for high and low-temperature LSB are comprehensively discussed.The solutions from the aspects of electrolyte and electrode materials are discussed to solve the aggravating shuttle effect and thermal safety issues under high temperature and the sluggish reaction kinetics under low temperature.Moreover,some specific promising solutions to extend the operating temperature range of LSB are also proposed and highlighted,which provide potential research directions on the practical LSB application in future.

Seed Priming Improves Enzymatic and Biochemical Performances of Rice During Seed Germination under Low and High Temperatures

As an abiotic stress,adverse germination temperatures cause serious disruptions in physiological and biochemical processes involved in seed germination.Using a factorial experiment,we examined the effects of different seed priming treatments on enzymatic and biochemical performances of rice seed germination under different temperatures.Each of the rice genotypes(Hashemi,Sadry-domsefid,IRON-70-7053-7 and NORIN-22)was primed with hydro-hardening,KCl,CaCl2 and ascorbic acid(AsA)and without a priming agent as a control at low(15℃),optimum(25℃)and high(35℃)germination temperatures.The results showed that the enzymatic and biochemical performances of all the rice genotypes were affected by the seed priming agents,especially under the low germination temperature.At 15℃,seed priming with AsA was found to be the best agent for the activities of amylase,α-amylase,catalase(CAT),peroxidase(POX),ascorbate peroxidase(APOX)and superoxide dismutase(SOD)as well as the content of soluble sugars in the NORIN-22 genotype,and for protease activity and soluble protein content in the IRON-70-7053-7 genotype.SOD at the low germination temperature and CAT,POX and protease at the optimum and high germination temperatures were the most important enzymes in occurrence of germination potential in terms of seedling length,vigor index,normal seedling rate and germination rate.Under the priming agents,the highest changes in normal seedling rate were observed at the low and optimum germination temperatures by AsA priming in the Hashemi and NORIN-22 genotypes,and at the high germination temperature under KCl priming in the Hashemi genotype.

Hydrogen production at intermediate temperatures with proton conducting ceramic cells:Electrocatalytic activity,durability and energy efficiency

Proton conducting ceramic cells(PCCs)are an attractive emerging technology operating in the intermediate temperature range of 500 to 700℃.In this work,we evaluate the production of hydrogen at intermediate temperatures by proton conducting ceramic cell electrolysis(PCCEL).We demonstrate a highperformance steam electrolysis owing to a composite positrode based on BaGd_(0.8)La_(0.2)Co_(2)O_(6-δ)(BGLC1082)and BaZr0.5Ce0.4Y0.1O3-δ(BZCY541).The high reliability of PCCEL is demonstrated for 1680 h at a current density as high as-0.8 A cm^(-2)close to the thermoneutral cell voltage at 600℃.The electrolysis cell showed a specific energy consumption ranging from 54 to 66 kW h kg^(-1)that is comparable to state-of-the-art low temperature electrolysis technologies,while showing hydrogen production rates systematically higher than commercial solid oxide ceramic cells(SOCs).Compared to SOCs,the results verified the higher performances of PCCs at the relevant operating temperatures,due to the lower activation energy for proton transfer comparing with oxygen ion conduction.However,because of the p-type electronic conduction in protonic ceramics,the energy conversion rate of PCCs is relatively lower in steam electrolysis.The faradaic efficiency of the PCC in electrolysis mode can be increased at lower operating temperatures and in endothermic conditions,making PCCEL a technology of choice to valorize high temperature waste heat from industrial processes into hydrogen.To increase the faradaic efficiency by optimizing the materials,the cell design,or the operating strategy is a key challenge to address for future developments of PCCEL in order to achieve even more superior techno-economic merits.

Tensile Properties and Prediction Model of Recombinant Bamboo at Different Temperatures

The destruction of recombinant bamboo depends on many factors,and the complex ambient temperature is an important factor affecting its basic mechanical properties.To investigate the failure mechanism and stress–strain relationship of recombinant bamboo at different temperatures,eighteen tensile specimens of recombinant bamboo were tested.The results showed that with increasing ambient temperature,the typical failure modes of recombinant bamboo were flush fracture,toothed failure,and serrated failure.The ultimate tensile strength,ultimate strain and elastic modulus of recombinant bamboo decreased with increasing temperature,and the ultimate tensile stress decreased from 154.07 to 96.55 MPa,a decrease of 37.33%,and the ultimate strain decreased from 0.011 to 0.008,a decrease of 26.57%.Based on the Ramberg-Osgood model and the pseudo‒elastic design method,a predictive model was established for the tensile stress–strain relationship of recombinant bamboo considering the temperature level.The model can accurately evaluate the tensile stress–strain relationship of recombinant bamboo under different temperature conditions.

Quasi-static and low-velocity impact mechanical behaviors of entangled porous metallic wire material under different temperatures

To improve the defense capability of military equipment under extreme conditions,impact-resistant and high-energy-consuming materials have to be developed.The damping characteristic of entangled porous metallic wire materials(EPMWM)for vibration isolation was previously investigated.In this paper,a study focusing on the impact-resistance of EPMWM with the consideration of ambient temperature is presented.The quasi-static and low-velocity impact mechanical behavior of EPMWM under different temperatures(25℃-300℃)are systematically studied.The results of the static compression test show that the damping energy dissipation of EPMWM increases with temperature while the nonlinear damping characteristics are gradually enhanced.During the impact experiments,the impact energy loss rate of EPMWM was between 65%and 85%,while the temperatures increased from 25℃to 300℃.Moreover,under the same drop impact conditions,the overall deformation of EPMWM decreases in the temperature range of 100℃-200℃.On the other hand,the impact stiffness,energy dissipation,and impact loss factor of EPMWM significantly increase with temperature.This can be attributed to an increase in temperature,which changes the thermal expansion coefficient and contact state of the internal wire helixes.Consequently,the energy dissipation mode(dry friction,air damping,and plastic deformation)of EPMWM is also altered.Therefore,the EPMWM may act as a potential candidate material for superior energy absorption applications.