Impact Of Elevated Temperature Research Articles

The impact of elevated temperatures and CO2 on seed germination and early plant morphology: The case of native Fabaceae plants in the UAE

The impact of elevated temperatures and CO2 on seed germination and early plant morphology: The case of native Fabaceae plants in the UAE

Impact of elevated temperatures on the genetic and morpho-physiological traits of cotton genotypes cultivation

Impact of elevated temperatures on the genetic and morpho-physiological traits of cotton genotypes cultivation

Thermal effects on mechanical and failure behaviors of anisotropic shale subjected to direct shear

The stimulation of shale reservoirs frequently involves significant shear failure, which is crucial for creating fracture networks and enhancing permeability to boost production. As the depth of extraction increases, the impact of elevated temperatures on the anisotropic shear strength and failure mechanisms of shale becomes pronounced, yet there is a notable lack of relevant research. This study conducts, for the first time, direct shear experiment on shales at four different temperatures and seven bedding angles. By employing acoustic emission (AE) and digital image correlation (DIC) techniques, the evolution of damage and the mechanism of crack propagation under anisotropic direct shearing at varying temperatures is revealed. The results indicate that both shear displacement and strength of shale increase with temperature across different bedding angles. Additionally, shale demonstrates distinct brittle failure characteristics under various conditions during direct shearing tests. The types of anisotropic shear failure observed under the influence of temperature include central shearing fracture, central shearing with secondary fracture, and deflected slip along the bedding. Moreover, the temperature effect enhances shear-induced crack propagation along bedding planes. Shear failure in shale predominantly occurs during higher loading stages, which coincide with a substantial amount of AE signals. Finally, the introduction of the anisotropy index and temperature sensitivity coefficient further elucidates the interaction mechanism between thermal effects and anisotropy. This study offers a novel methodology to explore the anisotropic shear failure behavior of shale under elevated temperatures, and also provides crucial theoretical and experimental insights into shear failure behavior relevant to practical shale reservoir stimulation.

Timing-dependent effects of elevated temperature on reproductive traits in the European corn borer moth.

Elevated temperature often has life stage-specific effects on ectotherms because thermal tolerance varies throughout ontogeny. Impacts of elevated temperature may extend beyond the exposed life stage, if developmental plasticity causes early exposure to carry over, or if exposure at multiple life stages cumulatively produces effects. Reproductive traits may be sensitive to different thermal environments experienced during development, but such effects have not been comprehensively measured in Lepidoptera. In this study, we investigate how elevated temperature at different life stages alters reproduction in the European corn borer moth, Ostrinia nubilalis. We tested effects of exposure to elevated temperature (28°C) separately or additively during larval, pupal, and adult life stages compared to control temperatures (23°C). We found that exposure to elevated pupal and adult temperature decreased the number of egg clusters produced, but exposure limited to a single stage did not significantly impact reproductive output. Furthermore, elevated temperature during the pupal stage led to a faster transition to the adult stage and elevated larval temperature altered synchrony of adult eclosion, either by itself or combined with pupal temperature exposure. These results suggest that exposure to elevated temperature during development alters reproduction in corn borers in multiple ways, including through carry-over and additive effects. Additive effects of temperature across life stages are thought to be less common than stage-specific or carry-over effects, but our results suggest thermal environments experienced at all life stages need to be considered when predicting reproductive responses of insects to heatwaves.

Impacts of elevated temperature, decreased salinity and microfibers on the bioenergetics and oxidative stress in eastern oyster, Crassostrea virginica

Projected increases in temperature and decreases in salinity associated with global climate change will likely have detrimental impacts on eastern oyster, Crassostrea virginica, as these variables can influence physiological processes in these keystone species. We set out to determine how the interactive effects of temperature (20 °C or 27 °C) and/or salinity (27‰ or 17‰) impacted the energetic reserves, aerobic and anaerobic metabolism, and changes to oxidative stress or total antioxidant potential as a consequence of an altered environment over a 21-day exposure. Gill and adductor muscle were used to quantify changes in total glycogen and lipid content, Electron Transport System and Citrate Synthase activities, Malate Dehydrogenase activity, Protein Carbonyl formation, lipid peroxidation, and total antioxidant potential. A second exposure was performed to determine if these environmental factors influenced the ingestion of microfibers, which are now one of the leading forms of marine debris. Elevated temperature and the combination of elevated temperature and decreased salinity led to an overall decline in oyster mass, which was exacerbated by the presence of microfibers. Changes in metabolism and oxidative stress were largely influenced by time, but exposure to elevated temperature, decreased salinity, the combination of these stressors or exposure to microfibers had small impacts on oyster physiology and survival. Overall these studies demonstrate that oyster are fairly resilient to changes in salinity in short-term exposures, and elevations in temperature or temperature combined with salinity result in changes to the oyster energetic response, which can be further impacted by the presence of microfibers.

Analysis of converter transformer pressboard insulation degradation under surge using mathematical morphology

Nowadays, with the significant expansion of industrial growth, the bulk power requirement can only be satisfied through high-voltage direct current HVDC transmission. The converter transformer is the utmost vital part of the HVDC transmission. Pressboard insulation is most commonly used as inter-disc insulation in converter transformers. During working conditions due to elevated temperature and different operational stresses, insulation material gets deteriorated. It may cause a risk to the life of the converter transformer. The effects of elevated temperatures as well as frequency on pressboard insulation of the converter transformer are examined in this study. The condition evaluation and morphological changes in pressboard insulation at elevated temperatures can evaluate with the help of frequency domain spectroscopy (FDS) and atomic force microscopy (AFM) techniques. The impact of elevated temperatures on insulation material can be analyzed based on surface roughness and dielectric parameters. In MATLAB Simulink environment, a dual winding single-phase converter transformers valve side star winding 60 discs model is constructed for impulse test. Based upon arrival time and velocity of traveling wave, insulation degradation location can be identified by using mathematical morphology. The simulation results demonstrate that the suggested method can notably located degradation across disc winding.

Temperature effects on adsorption and capillarity water retention mechanisms in constrained unsaturated soils

AbstractThis paper focuses on the impact of elevated temperatures on the adsorptive and capillarity water retention mechanisms of unsaturated soils under constrained (constant volume) conditions. This topic is critical for simulating the thermo-hydraulic behavior of soils in hydrogeological or geotechnical applications, including climate change effects on near surface soils, energy piles or soil borehole thermal energy storage systems in unsaturated soil layers, and buffers for geological nuclear waste repositories. A nonisothermal soil water retention curve (SWRC) that separately considers the temperature-dependency of the key parameters governing adsorptive and capillarity water retention mechanisms and soil physical parameters (e.g., surface tension, contact angle, adsorption capacity, cation exchange capacity, mean cavitation suction, air entry value and equilibrium film thickness) was developed to provide insights into the impact of temperature on water retention over the full suction range. The nonisothermal SWRC was validated using experimental data on high plasticity clays, with a good prediction of temperature effects on adsorption and capillarity water retention mechanisms in constrained unsaturated soils.

Impacts of elevated temperature and vapour pressure deficit on leaf gas exchange and plant growth across six tropical rainforest tree species.

Elevated air temperature (Tair) and vapour pressure deficit (VPDair) significantly influence plant functioning, yet their relative impacts are difficult to disentangle. We examined the effects of elevated Tair (+6°C) and VPDair (+0.7 kPa) on the growth and physiology of six tropical tree species. Saplings were grown under well-watered conditions in climate-controlled glasshouses for 6 months under three treatments: (1) low Tair and low VPDair, (2) high Tair and low VPDair, and (3) high Tair and high VPDair. To assess acclimation, physiological parameters were measured at a set temperature. Warm-grown plants grown under elevated VPDair had significantly reduced stomatal conductance and increased instantaneous water use efficiency compared to plants grown under low VPDair. Photosynthetic biochemistry and thermal tolerance (Tcrit) were unaffected by VPDair, but elevated Tair caused Jmax25 to decrease and Tcrit to increase. Sapling biomass accumulation for all species responded positively to an increase in Tair, but elevated VPDair limited growth. This study shows that stomatal limitation caused by even moderate increases in VPDair can decrease productivity and growth rates in tropical species independently from Tair and has important implications for modelling the impacts of climate change on tropical forests.

The impact of high temperature on mechanical properties and behaviors of sandstone

The impact of high temperature environments on the physical and mechanical properties of rocks is a significant factor to consider. The investigation into the impact of elevated temperatures on the physical and mechanical characteristics of rocks holds great importance in the advancement and exploitation of deep-seated mineral reserves, as well as in ensuring the safety and stability of subterranean engineering projects. This study utilizes the state-of-the-art GCTS Mechanical Loading Test System to conduct uniaxial and triaxial compression tests on sandstone after thermal treatment from 25°C to 650°C. In addition, XRD, SEM and nuclear magnetic resonance experiments were carried out on the sandstone after thermal treatment. The aim of the experiments is to provide a quantitative characterization of mechanical properties and behaviors of the rock samples. The results show that the mass, density, and wave velocity of sandstone decrease with increasing temperature, while volume and porosity increase. The mass, volume, and rate of density change of sandstone exhibit a significant increase when subjected to temperatures above 500°C. The uniaxial compressive strength and elastic modulus exhibit an initial increase followed by a subsequent decrease as the temperature rises, with 300°C serving as the critical turning point. The axial peak strain and Poisson’s ratio increase with increasing temperature. The cohesion decreases with increasing temperature, while the internal friction angle increases. Additionally, it is observed that the rate of change for both properties exhibits an increase beyond the temperature threshold of 400°C.

Elevated CO2 ameliorates the high temperature stress effects on physio-biochemical, growth, yield traits of maize hybrids

The rising temperatures and levels of carbon dioxide in the atmosphere are anticipated to have a significant impact on the productivity of agricultural crops. Although, the individual effects of elevated CO2 and temperature have been extensively studied in C3 and C4 crops, there remains a scarcity of research investigating their interactive effects specifically on maize hybrids. The impact of elevated temperature and its interaction with elevated CO2 on phenology, physiology, biomass, and grain yield of maize hybrids was assessed in a field experiment using Free Air Temperature Elevation (FATE) facility. The results showed that elevated temperature (eT) increased the anthesis silking interval (ASI), while the presence of elevated CO2 along with elevated temperature (eT + eCO2) mitigated this effect. The differential expression were observed between hybrids depending on their genetic potential. Furthermore, the net photosynthetic rate (Anet), stomatal conductance (gs), and transpiration rate (Tr) of hybrids decreased under elevated temperature but eT + eCO2 condition helped in reverting its impact to some extent. In term of leaf composition, the highest level of total soluble sugars (TSS) and starch was observed under eT + eCO2 conditions, possibly due to improved Anet in the presence of elevated eCO2. The negative impact of eT was also evident through increased proline and MDA content, but eT + eCO2 ameliorated the adverse effect of eT. The biomass and grain yield also responded similarly, among the hybrids 900M GOLD recorded superior performance for grain yield at eT condition exceeding 35 °C. On the other hand, DHM117 experienced a significant reduction in grain yield under eT, but performed better under eT + eCO2 due to its improved physiological response to eCO2. The study indicated that elevated levels of carbon dioxide can actually mitigate the detrimental effects of elevated temperature on maize crop. This positive impact on maize crop can be attributed to an enhanced physiological performance in the presence of eCO2 which enables the plants to maintain satisfactory yield levels despite the challenging environmental conditions.

Optimization of Flow-By CO2 Electrolyzers: Impact of Differential Pressure and Gas Diffusion Layer Composition

The electrochemical reduction of CO2 (eCO2R) into valuable chemicals offers a great ecological solution to lower anthropogenic CO2 in the atmosphere, since it can close the carbon cycle by utilizing renewable energy, resulting in a sustainable carbon recycling system. Consequently, it has gathered significant scientific interest over the past decade [1,2]. However, to make significant progress towards making the process industrially feasible, it would be beneficial to replace the typical anodic oxygen evolution reaction at the counter electrode with an economically more interesting one, like alkane dehydrogenation, while at the same time lowering cell potential and increasing energy efficiency. However, this requires the CO2 reduction to operate efficiently at elevated temperatures (up to 100°C) [3]. Unfortunately, little is known on the impact of elevated temperatures on the overall performance of CO2 electrolyzers and its components.In this research, we studied the effect of increasing the temperature on CO2 electrolyzers to ultimately enable selective and stable eCO2R to formic acid not only at room temperature. Heating the system leads to many changes (e.g. decreased electrolyte surface tension, decreased hydrophobicity of the gas diffusion layer (GDL), lower dissolved CO2 content and, increased CO2 diffusion coefficient), all affecting the performance of a conventional CO2 electrolyzer, consequently raising the need for re-evaluating many of its components and their configuration, considering they have been optimized for operation at ambient conditions. Specifically, we focused on the three-phase boundary, where the eCO2R reaction actually takes place. Logically, it is important that this boundary is at the exact location of the catalyst layer (CL), as the catalyst is the active species towards the desired reaction. To this end, GDLs are specifically designed to align this boundary to the right location through variations in hydrophobic additives, thickness, porosity, etc. However, we have found that all these efforts to perfect the GDL's properties can be forfeited if the differential pressure across it were to change as it shifts the three-phase boundary. A shift inwards the GDL will result in a flooded CL, lengthening the diffusion path of the gaseous CO2 in the electrolyte to the active sites of the CL resulting in increased hydrogen evolution. A shift outward the GDL will result in a CL that is not fully used, as such lowering the activity. Since the CL is a thin layer, it can be easily understood that the margin within which the boundary can shift without becoming catastrophic for the overall performance is very small, making it extremely critical to have precise control over its position. Changing the temperature of the system will affect the location of the boundary layer and by optimizing the differential pressure we can shift its location back to its optimal position and increase the performance of the CO2 electrolyzer.We investigated the influence of deliberately altering the differential pressure across a GDE in a flow-by electrolyzer with Bi2O3 nanoparticles for the eCO2R towards formate, at different temperatures. At higher temperatures (i.e. 85°C), flooding was a pronounced problem, which resulted in a rapid decrease of performance, and after 24 hours of electrolysis only a 40% faradaic efficiency towards formate (FEHCOOH) was maintained from the initial 70%. We discovered that by increasing the differential pressure, by elevating the backpressure at the gas side, we could limit flooding of the GDE. By mitigating the flooding, the system was able to maintain a better performance, i.e. FEHCOOH of 65% after 24 hours of electrolysis was maintained, which is a 1.6 factor increase (Figure). The present findings confirm that, without altering any of the more significant electrochemical aspects of the electrolyzer, it is possible to increase performance by solely varying the differential pressure over the GDE, showing the importance of also optimizing the operational conditions.Once the optimal differential pressure of the system was established, it was still necessary to investigate the GDE structure itself. Indeed, the GDE should be designed to appropriately mediate all transport processes necessary to achieve high eCO2R performance and further reduce flooding phenomena, by favourably affecting CO2 transport, local pH and water transport [4]. Therefore, the next step was to investigate and compare other commercially available GDLs. For this research we selected commercially available GDLs that are primarily used in high-temperature proton exchange fuel cells, since their required characteristics (hydrophobicity, thickness and pore structure) are similar to the needs of our system.By re-evaluating and optimizing these (operational) conditions, we are getting closer to making the electrochemical CO2 reduction efficient, also at elevated temperatures.[1] https://doi.org/10.1016/j.petlm.2016.11.003[2] https://doi.org/10.1016/j.joule.2017.09.003[3] https://doi.org/10.1002.celc.201900872[4] https://doi.org/10.1038/s41578-021-00356-2 Figure 1

Influence of heavyweight aggregate on the fresh, mechanical, durability, and microstructural properties of self-compacting concrete under elevated temperatures

Recently, attention has been drawn to the production of heavyweight self-compacting concrete which combines the benefits of heavyweight concrete (HWC) and self-compacting concrete (SCC). This paper investigates the effect of using the barite coarse aggregate (size 4–8 mm) as substitution of volume of the natural coarse aggregate (size 4–8 mm) with various percentages (0, 20, 40, 60, 80, and 100%) on self-compacting concrete (SCC) properties. Slump-flow, T500 time, V-funnel, J-ring, L-box test, and fresh density were used to evaluate the fresh SCC characteristics. However, compressive strength, flexural strength, splitting tensile strength, water absorption, dry density, sulphate attack, and ultrasonic pulse velocity were used to evaluate the mechanical and durability characteristics. In addition, the impact of elevated temperatures (600 °C and 800 °C) on SCC containing various ratios of barite was studied through the evaluation of the density and compressive strength losses. Also, using fourier transform infrared radiation (FTIR) technique, mercury intrusion porosimetry (MIP), and scanning electron microscope (SEM), a microstructural investigation was conducted on hardened SCC containing various ratios of barite to determine the behaviour of barite in comparison to the control mix. The results demonstrate a slight negative effect on fresh and hardened of SCC properties with increasing percentages of barite. However, concrete incorporating up to 80% barite fulfilled all of the EFNARC-recommended criteria for SCC and the dry density of samples containing 80% barite was 2.660 kg/m3. Therefore, the self-compacting and heavyweight concrete characteristics were met by incorporating 80% barite as coarse aggregates. Nevertheless, the rate of increment in compressive strength increased with increasing barite ratios after exposure to 15 cycles of sulphate attack compared to the non-exposed samples.

Empirical investigation of temperature effects on the mechanical properties of glass textile reinforced concrete

Textile Reinforced Concrete (TRC) is an innovative composite material that combines fine-grained concrete with textile fibers, resulting in improved mechanical properties for building materials. This research focuses on the impact of elevated temperatures on the mechanical characteristics of Glass TRC. Specifically, it investigates the tensile strength and bonding between glass rovings and fine-grained concrete. The study includes pullout tests on bonding TRC specimens and uniaxial tensile tests on tensile specimens exposed to temperatures of 30°C, 80°C, 150°C, and 200°C. The experimental results reveal that at 30 °C, the fiberglass mesh exhibits strong adhesion to fine-grained concrete, with an average bonding strength of 23.2 N/mm and an anchor length of approximately 120 mm. However, as the temperature increased to 150 °C and 200 °C, the bonding strength decreased by 33.4% and 46.2%, respectively. The tensile strength of TRC was 1470 MPa at 30 °C, but it decreased by 21.9% and 30.4% at temperatures of 150ºC and 200ºC.

Impacts of elevated temperature on morphology, oxidative stress levels, and testosterone synthesis in ex vivo cultured porcine testicular tissue

Heat stress has been recognized as a major environmental factor affecting reproductive performance in livestock. However, the underlying mechanisms through which high temperature impairs testicular function remain elusive. This study aimed to investigate the effects of high temperature on morphology, oxidative stress levels, and testosterone synthesis in porcine testicular tissue in vitro. Testicular tissue samples from boars were subjected to different temperature conditions: control (37 °C) and heat stress (39 °C) for 4 h. The morphology of the testicular tissue was assessed using histological analysis, while oxidative stress levels were evaluated by measuring reactive oxygen species (ROS) production and antioxidant enzyme activities. Additionally, the expression of key enzymes involved in testosterone synthesis was examined using quantitative real-time polymerase chain reaction (qRT-PCR). Our results revealed that exposure to high temperatures significantly altered testicular tissue morphology. Histological analysis demonstrated degeneration and disorganization of seminiferous tubules, reduction in germ cell populations, and disruption of the blood-testis barrier. Moreover, high-temperature exposure significantly increased ROS production and decreased the activities of antioxidant enzymes (p < 0.05), indicating elevated oxidative stress levels in the testicular tissue. Furthermore, qRT-PCR analysis showed that high-temperature exposure suppressed the expression of key enzymes involved in testosterone synthesis, including steroidogenic acute regulatory protein and cytochrome P450 family 11 subfamilies A member 1. These findings suggest high temperature impairs testicular function by disrupting testicular morphology, inducing oxidative stress, and inhibiting testosterone synthesis. In conclusion, our study demonstrates that high-temperature exposure adversely affects morphology, oxidative stress levels, and testosterone synthesis in porcine testicular tissue. These findings provide insights into the potential mechanisms underlying heat-induced reproductive dysfunction in male pigs and highlight the importance of heat stress management in swine production to maintain optimal reproductive performance. Further investigations are warranted to elucidate the precise molecular pathways involved in the heat-induced testicular impairments observed in this study.

Investigation on the impact of elevated temperature on sustainable geopolymer composite

Geopolymer concrete (GPC) is an eco-friendly, sustainable, cementless and green concrete. It could be an alternative to the conventional concrete. In alkaline circumstances, the alumina and silica concentration in geopolymer concrete creates the geopolymer bond, while regular concrete creates C-S-H (calcium silicate hydrate bond). The final result of the geopolymer bond does not include any water. At elevated temperatures, geopolymer concrete would thus be more stable. Due to its greater strength and durability quality, geopolymer concrete may be the ideal replacement for ordinary portland cement (OPC) concrete. This research intends to examine how specimens of geopolymer concrete and regular concrete respond to exposure to increased temperatures between 100°C and 800°C. Mass loss, ultrasonic pulse velocity, compressive strength, X-ray diffraction, thermogravimetric analysis and derivative thermogravimetric analysis were all examined throughout the experimental examination. Both concrete specimens lose mass or weight as the exposure temperature rises; OPC concrete samples spalls at 600°C, while GPC sample fail at 800°C. GPC specimens lose around 12% of their original mass after being exposed to temperatures of 800°C, while OPC specimens lose about 7%. The GPC specimens maintained 60% of their initial compressive strength after being exposed to a temperature of 700°C, but the OPC concrete specimens only kept 52%. With each increase in exposure to extreme temperatures, the peaks of quartz and cristobalite are lowered. Only the form or structure of the mineral oxide would change; the chemical linkages would remain. The GPC samples subjected to temperatures of 100°C exhibit effective thermal stability than all other specimens exposed to extreme temperatures. As the exposure temperature rises, the GPC specimens become more thermally stable. According to the experimental findings, the GPC specimens’ bonding structure makes them more resistant to high temperatures than regular concrete specimens. Micropores are present in the voids of the geopolymer matrix, while mesopores and micropores are present in the voids of the OPC matrix. While OPC bonding is C-S-H formed by the hydration of lime and silica contained in the cement, the geopolymer bonding did not include the water content in the final or end result of geopolymerisation for strengthening.

Impact of heat treatment on spark plasma sintered magnesium-containing lightweight AlFeCuCrMg high entropy alloy

In this study, the impact of heat treatments on AlFeCuCrMgx (x = 0, 0.5, 1, and 1.7) alloys prepared by mechanical alloying and spark plasma sintering were examined. The behavior of these high-entropy alloys (HEAs) was thoroughly studied after they had been heated to 470, 600, and 820 °C in a natural atmosphere. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to study the phase evolution of the heat-treated alloys. The XRD data of the AlFeCuCrMgx (x = 0 and 0.5) alloys heated at 470, 600, and 820 °C present the dispersion of FCC Cu particles at the grain boundaries of parental phases. By contrast, the AlFeCuCrMgx (x = 1 and 1.7) alloys do not exhibit this characteristic. The microstructures of these alloys have been correlated with these results. Their sub-micron structures indicate that the precipitates are unaffected up to 820 °C. The impact of elevated temperatures on the AlFeCuCrMgx alloys was thoroughly examined based on conventional theory.

Impact of elevated temperatures on properties of concrete with blast furnace slag as partial replacement of fine aggregate as green building material

Concrete is widely used as construction material because it’s high durability and fire resistance. When any structures exposed to fire, its room temperature will raise continually, which cause deterioration of concrete structures. During high temperatures concrete loss it structural capacity and it may require strengthen and rehabilitations. This paper is an efforts to investigate the effect of elevated temperature on conventional concrete and concrete with granulated blast furnace slag( GBFS) as partial replacement of fine aggregate in proportions of 20%, 40 % and 60 % and 1 % steel fibers. The strength parameter was determine and compared with conventional concrete at controlled elevated temperatures like 200°C, 400°C, 600°C, 800°C, 1000°C for 0.5 hour, 1 hour and 1.5 hour constant heating and tested after 1.0 hours of natural cooling. This experimentation shown the strength of concrete with GBFS 40 performs well at all elevated temperatures as compared with conventional concrete.

Impact of Elevated Temperature and Carbon dioxide on Seed Physiology and Yield

Food security is of utmost priority to humankind. This is the implication of various interconnected factors that lead to climate change. Elevated temperature and carbon dioxide levels are just 2 of these. The nutrient is an inseparable aspect of food. The change in climate is posing threat not only to the amount of available food but also to the nutrients laden in the food items. Seeds are the miniature form of plants and are a reflection of their future health and nutritional status. The changes in environmental factors predominantly challenge the growth and development of a seed. This review is an attempt to understand the impact of elevated CO2 and temperature on seed germination, the nutritional status of the seed and the yield in form of total seed production. It gives a direction for analysis and future studies that may use the latest available tools like gene editing to tackle and counteract the retarding effect of climate change on these parameters of seed, thereby offering a climate resilient agriculture.

Numerical analysis of a steel frame in a fire situation

In the paper, the stages of modelling of a steel frame under fire conditions were discussed. Numerical computations were performed using SIMULIA Abaqus software. The way of defining and developing the computational model was described. In the numerical procedure adopted in the paper, much attention was paid to formulas related to various types of the model parameters that depend on the fire temperature. The results were shown in a graphic form. They were compared with the results obtained from the analysis, in which the impact of elevated temperatures was disregarded. Based on numerical simulation results, an attempt was made to assess the effect of fire on the steel frame components. The paper is exploratory in character and provides an introduction to the issues related to the modelling of steel structure fires. The numerical modelling of the structure fire described in the paper can have practical potential for structural engineers.

A review of the role of elevated temperatures on the mechanical properties of fiber-reinforced geopolymer (FRG) composites

In recent years geopolymers (GPs) have emerged as environmentally friendly construction materials and as incombustible mineral matrices for use in fiber-reinforced composites. The incorporation of fibers, either in discrete or continuous form, changes brittle behavior to ductile or quasi-ductile, resulting in high-performance, fiber-reinforced geopolymer (FRG) composites.For a larger-scale use of FRGs in construction and infrastructure industries, the impact of elevated temperatures is an inevitable matter of concern. The results obtained from existing studies on the fire response of GP composites differ significantly due to the differences in adopted geopolymer (GP) matrix designs, fibre types and their dosage, or testing methods. Mechanical properties of FRGs, including flexural and tensile strength, fracture toughness, and compressive strength, are comprehensively reviewed at ambient and elevated temperature levels and then correlated to microstructural changes.The article at hand aims to establish a conceptual and technical novel background for the current understanding of the combined influence of such factors and deliver an in-depth review of their effects on the performance of FRG at elevated temperatures depending on the fiber typology. Significant findings show inherently superior heat resistance for FRG composites as compared to either cement or polymer-based matrices, while it requires careful compositional design for sufficient processability, effectiveness of fibers, low volume changes and strength endurance. Furthermore, pointed out are potential applications and recommendations for heat and fire resistance, all of which still need to be addressed through further experimental and numerical studies.