Environmental Temperature Fluctuations Research Articles

Quantitative analysis of the impact of room temperature stability on cryostat performance

The constant temperature in laboratories is crucial for precise low-temperature measurements. Currently, there are no reports on the specific temperature needs for such experiments or quantitative analyses of how room temperature fluctuations affect cryostat control. This paper proposes a method to quantitatively analyze these fluctuations and their impact on cryostat temperature control. Taking the cryostat using for 2 K-5 K thermodynamic temperature measurement as the research object, and conducts model simulation and experimental validation. The research results indicate the primary influence on the sphere’s temperature is the time-dependent fluctuation of the room temperature. As temperature fluctuations propagate from the cryostat’s outer casing to the sphere, heat conduction is the dominant factor. The temperature fluctuations inside the system caused by environmental temperature fluctuations can be quantitatively expressed by a simple linear formula, with the coefficient being the fluctuation attenuation rate, which is 6.590 × 10-4 in this system. The deviation between experimental results and simulation results is within 5 %. To keep the sphere’s ambient temperature influence below 0.077mK, or 20 % of cryocooler-induced fluctuations, the room temperature must be controlled within 0.12 °C. In addition, the fluctuation period of room temperature is controlled below 1 h, the 0th flange is thickened, the rod is lengthened, and the material of the rod is changed to G10 above 4.2 K and stainless steel below 4.2 K can also effectively attenuate the influence on system temperature control.

Wind Rose Analysis of Temperature Variation with Sensor Implantation Technique for Wind Turbine

This study focuses on analysing the impact of seasonal variations in heat on different parts of a "wind energy system," serving as a representative mechanical system. The proposed methodology utilizes wind rose analysis, offering a straightforward means to assess heat transfer effects, applicable to any mechanical system comprising numerous small heat-dissipating components. Furthermore, this work elucidates the correlation between mechanical component performance and heat dissipation impact, providing breakdown alerts for various wind turbine components. Additionally, it analyses the influence of mechanical part temperatures on energy generation, highlighting how high temperatures can indicate component deterioration, such as bearing damage. Notably, the study focuses on wind speeds ranging from 10 to 15 m/s, a typical operational range for wind turbines. By employing wind rose charts and real-time readings, the graded heat dissipating potential of mechanical parts under various wind velocities and weather conditions is determined. Moreover, the study emphasizes the significance of heat transfer analysis in optimizing wind turbine performance, demonstrating how temperature differentials between mechanical components and the environment, along with increased surface area, affect heat transfer. The proposed analysis underscores the importance of considering heat's impact on each mechanical component in tandem with seasonal environmental temperature fluctuations. The wind rose methodology, integrated with sensor implantation, emerges as a cost-effective tool for studying -level heat variances in mechanical systems, enabling the development of heat profiles for future turbine designs and computational fluid dynamics (CFD) analyses. As heat transfer coefficient increases the wind turbine performance decrease. The heat transfer coefficient decreases 14.28% from rainy to winter season and 42.85% from winter to summer season. The wind rose analysis provides valuable insights into wind patterns and characteristics at a specific location, which can inform decision-making in various fields such as energy, construction, environmental management, and safety planning. As the turbine temperature increases the wind velocity decreases. Here it decreases 28 % from rainy to winter season.

Wavelet neural network algorithm for hybrid GA in infrared CO2 gas sensor

As the economy develops and the environmental impact of the greenhouse effect becomes more apparent, the need for precise measurement of specific gas concentrations in the air has become increasingly pressing. Nevertheless, as a representative of greenhouse gases, CO2 gas detectors are susceptible to environmental temperature fluctuations, which impairs the accuracy of detection. To address this issue, the research team innovatively combined the genetic algorithm (GA) and the wavelet neural network (WNN) to develop a solution for the temperature compensation problem of the infrared CO2 gas sensor. The non-dominant sorted genetic algorithm II (NSGA-II) was integrated into the GA to achieve a balance between the accuracy, complexity, and temperature performance of the model through multi-objective optimization. The results showed that compared with other existing models, the GA-WNN model proposed in this study can significantly reduce the difference between the detected values and the actual environmental values under various temperature conditions when processing data. Especially at an ambient temperature of 49 °C, for a true CO2 concentration of 2000 ppm, the detection value processed by the GA-WNN algorithm was 2046 ppm, with a relative error of only 2.3 %, far lower than the 9.8 % of Faster RCNN algorithm and 11.5 % of WNN algorithm. The contribution of the research is the proposal of a novel temperature compensation method that significantly enhances the precision of infrared CO2 gas sensors. This is of paramount importance for enhancing the accuracy of gas detection in environmental monitoring and industrial control.

Endophytic Bacterial Biofilm-Formers Associated with Antarctic Vascular Plants.

Deschampsia antarctica and Colobantus quitensis are the only two vascular plants colonized on the Antarctic continent, which is usually exposed to extreme environments. Endophytic bacteria residing within plant tissues can exhibit diverse adaptations that contribute to their ecological success and potential benefits for their plant hosts. This study aimed to characterize 12 endophytic bacterial strains isolated from these plants, focusing on their ecological adaptations and functional roles like plant growth promotion, antifungal activities, tolerance to salt and low-carbon environments, wide temperature range, and biofilm formation. Using 16S rRNA sequencing, we identified several strains, including novel species like Hafnia and Agreia. Many strains exhibited nitrogen-fixing ability, phosphate solubilization, ammonia, and IAA production, potentially benefiting their hosts. Additionally, halotolerance and carbon oligotrophy were also shown by studied bacteria. While some Antarctic bacteria remain strictly psychrophilic, others demonstrate a remarkable ability to tolerate a wider range of temperatures, suggesting that they have acquired mechanisms to cope with fluctuations in environmental temperature and developed adaptations to survive in intermediate hosts like mammals and/or birds. Such adaptations and high plasticity of metabolism of Antarctic endophytic bacteria provide a foundation for research and development of new promising products or mechanisms for use in agriculture and technology.

Numerical investigation of photovoltaic performance improvement using Al2O3 nanofluid

To further elucidate the impact of fluctuations in environmental temperature and radiation intensity within a day on the temperature and performance of photovoltaic systems with and without nanofluid cooling, this study established a photovoltaic panel temperature and efficiency calculation model based on a nanofluid cooling system that considers the dynamic changes of photovoltaic panel temperature and air temperature over time. An empirical formula for predicting photovoltaic panel efficiency has been derived based on experimental data. Then a PV panel temperature and efficiency calculation model is established and validated. The simulation results show that using nanofluids to cool the PV panel can significantly reduce the temperature and improve the PV efficiency. Compared to the bare PV panel, the average PV panel temperature decreases by 7.99 ℃, 8.48 ℃, and 8.92 ℃ respectively when nanofluid volume fraction is 1 vol%, 3 vol%, and 5 vol%, and it decreases by 8.48 ℃, 9.27 ℃, and 9.94 ℃ respectively when nanofluid mass flow rate is 0.08 m3/h, 0.10 m3/h, and 0.12 m3/h. As the nanofluids' concentration increases, nanofluids' cooling ability in the high temperature range also increases.

Abiotic stressors in poultry production: A comprehensive review.

In modern animal husbandry, stress can be viewed as an automatic response triggered by exposure to adverse environmental conditions. This response can range from mild discomfort to severe consequences, including mortality. The poultry industry, which significantly contributes to human nutrition, is not exempt from this issue. Although genetic selection has been employed for several decades to enhance production output, it has also resulted in poor stress resilience. Stress is manifested through a series of physiological reactions, such as the identification of the stressful stimulus, activation of the sympathetic nervous system and the adrenal medulla, and subsequent hormonal cascades. While brief periods of stress can be tolerated, prolonged exposure can have more severe consequences. For instance, extreme fluctuations in environmental temperature can lead to the accumulation of reactive oxygen species, impairment of reproductive performance, and reduced immunity. In addition, excessive noise in poultry slaughterhouses has been linked to altered bird behaviour and decreased production efficiency. Mechanical vibrations have also been shown to negatively impact the meat quality of broilers during transport as well as the egg quality and hatchability in hatcheries. Lastly, egg production is heavily influenced by light intensity and regimens, and inadequate light management can result in deficiencies, including visual anomalies, skeletal deformities, and circulatory problems. Although there is a growing body of evidence demonstrating the impact of environmental stressors on poultry physiology, there is a disproportionate representation of stressors in research. Recent studies have been focused on chronic heat stress, reflecting the current interest of the scientific community in climate change. Therefore, this review aims to highlight the major abiotic stressors in poultry production and elucidate their underlying mechanisms, addressing the need for a more comprehensive understanding of stress in diverse environmental contexts.

Neuromodulatory Compensation of Cortical Neural Activity on Electrodeposited Pt/Ir Modified Microelectrode Arrays for Temperature Transients.

Temperature has a profound influence on various neuromodulation processes and has emerged as a focal point. However, the effects of acute environmental temperature fluctuations on cultured cortical networks have been inadequately elucidated. To bridge this gap, we have developed a brain-on-a-chip platform integrating cortical networks and electrodeposited Pt/Ir modified microelectrode arrays (MEAs) with 3D-printed bear-shaped triple chambers, facilitating control of temperature transients. This innovative system administers thermal stimuli while concurrently monitoring neuronal activity, including spikes and local field potentials, from 60 microelectrodes (diameter: 30 μm; impedance: 9.34 ± 1.37 kΩ; and phase delay: -45.26 ± 2.85°). Temperature transitions of approximately ±10 °C/s were applied to cortical networks on MEAs via in situ perfusion within the triple chambers. Subsequently, we examined the spatiotemporal dynamics of the brain-on-a-chip under temperature regulation at both the group level (neuronal population) and their interactions (network dynamics) and the individual level (cellular activity). Specifically, we found that after the temperature reduction neurons enhanced the overall information transmission efficiency of the network through synchronous firing to compensate for the decreased efficiency of single-cell level information transmission, in contrast to temperature elevation. By leveraging the integration of high-performance MEAs with perfusion chambers, this investigation provides a comprehensive understanding of the impact of temperature on the spatiotemporal dynamics of neural networks, thereby facilitating future exploration of the intricate interplay between temperature and brain function.

Dependence of frequency-temperature stability on support tethers in dual-beam piezoresistive sensing MEMS resonators

This paper investigates the dependence of frequency stability over temperature on support tethers in dual-beam piezoresistive length-extensional (LE) mode microelectromechanical systems (MEMS) resonators. The designed dual-beam resonator consists of two identical single-crystal silicon beams, which are mechanically coupled and excited into vibrating in opposite phase to eliminate the inherent capacitive feedthrough signals. Both straight and folded beams are adopted as the support tethers for the reported dual-beam piezoresistive resonators. Quality factor (Q) and temperature distribution across the resonators with various support tethers are investigated by finite element method (FEM) analysis. It is found that folded beam tethers can reduce the support loss and hence improve the Q for the designed dual-beam resonator, while it comes with a tradeoff of high temperature rise on resonator body. The reported dual-beam resonator with straight beam tethers has low temperature rise on the resonator body, which is less sensitive to environmental temperature fluctuations, compared to its counterpart with folded beam tethers. Experimental results show that the fabricated dual-beam piezoresistive resonator with four straight beam tethers achieves a 0.5 ppm frequency shifts in the temperature-control chamber, which is nearly four times better than those with folded beam tethers.

Enhancing the resistance of cementitious composites to environmental thermal fatigue using high-volume fly ash and steel slag

Daily fluctuations in environmental temperature induce thermal fatigue and cause degradation in concrete structures. This study introduces a novel approach of utilizing high-volume fly ash, steel slag fine aggregates, and basalt-polypropylene fibres to prevent degradation against environmental thermal fatigue (ETF). Five mixes were considered with variations in fine aggregate type, fibre length and volume. The compressive and flexural strengths were analysed after exposure to 60, 120, 180, 240, and 300 ETF cycles between 20 and 60 °C (at constant relative humidity). The residual compressive strength of mix with 100 % river sand and 100 % steel slag as fine aggregates was ∼106 % and ∼112 % respectively after 300 ETF cycles. The developed cementitious composites performed significantly better than the mixes utilized in the existing literature. The mix with 100 % steel slag aggregate even demonstrated a continual rise in compressive strength as opposed to mixes with river sand whose strength declined after 180 or 240 ETF cycles. Flexural strength also improved up to 180 ETF cycles and then started to decline in all mixes. A thorough microstructural analysis was also conducted using scanning electron microscopy, differential scanning calorimetry, and mercury intrusion porosimetry to gain further insights into the underlying mechanism of the newly introduced matrix composition against ETF.

Tensile and compressive properties of bamboo scrimber under different temperature conditions

AbstractBamboo scrimber demonstrates vulnerability to environmental temperature fluctuations, such as exposure to cold or fire, when deployed in structural applications. Consequently, its mechanical properties can substantially diverge from the intended design values under varying thermal conditions. This study aims to study the tensile and compressive properties of bamboo scrimber under different temperatures to provide data support for studying bamboo scrimber under low and high temperatures. The compressive properties of bamboo scrimber under temperatures ranging from −30°C to 250°C and the tensile properties under −20°C to 250°C were determined by a series of tests with a total of 125 specimens. The results show that the mass loss of bamboo scrimber increases gradually with the increase in temperature, and the increasing trend intensifies after 120°C. With the increase of temperature, the failure mode of the specimens under compression changes from the bottom compression cracking damage to the local destabilization of longitudinal fibers, while the tensile damage modes aren't influenced by temperature, and both “straight‐line” and “folded‐line” types of damage modes occur at different temperatures. The tensile and compressive strengths and elastic modulus of the specimens decreased with the increase in temperature, and the strength was more susceptible to the temperature than the elastic modulus: a rise in temperature from 20°C to 250°C resulted in a reduction of compressive strength and tensile strength by 80.80% and 84.11%, respectively, the compressive modulus and tensile modulus experienced decreases of 49.51% and 53.28%. Furthermore, equations of temperature influence coefficients of strength and elastic modulus were established based on the test results.Highlights Bamboo scrimber's mechanical properties under different temperatures are studied. Tendency and explanation of temperature influence coefficients are analyzed. Temperature coefficient equations for strength and elastic modulus are proposed.

Design Implementation of a Logger-Based Digital Thermometer

LM35 temperature sensor is a widely used 3-terminal sensor known for its precise temperature measurement capabilities without the need for external calibration circuitry. With a sensitivity of 10mV/°C, it operates within a temperature range of -55°C to 150°C, with an error margin of 0.5°C. This paper presents the development and testing of a logger-based digital thermometer using LM35 sensor, integrated with a dsPIC30F4013 digital signal processing controller, an LCD, a real-time clock (DS1307), and other essential components. The methodology involves the analysis of the sensor's sensitivity and its response under both stress and non-stress temperature conditions. The findings indicate that the sensor's output closely follows the theoretical sensitivity, with a negligible offset, ensuring accurate temperature measurements. Comparative analysis with a standard laboratory thermometer suggests that the digital sensor provides superior precision, with an error margin of ±0.01°C. The results confirm LM35's suitability for accurate ambient temperature monitoring and validation of environmental temperature fluctuations.

Response analysis of asymmetric monostable energy harvester with an uncertain parameter

The nonlinear piezoelectric vibration energy harvesting system offers a solution to the power supply challenge for low-power sensors. However, In practical engineering, structural parameter uncertainties arise from manufacturing errors, environmental temperature fluctuations, and changes in material properties. Besides, due to inherent flaws in the structure and materials, asymmetry may occur in the potential well, which leads to the complexity of the dynamic behavior exhibited in energy harvesting system. In this paper, in order to investigate the dynamics of the asymmetric monostable piezoelectric energy harvesting system under an uncertain parameter, the orthogonal polynomial approximation method is applied to transform the stochastic system into an equivalent deterministic system. Then, the responses of the equivalent deterministic system are used to reveal the stochastic behavior of the uncertainty system. The results indicate that, when the uncertainty intensity of the cubic nonlinear coefficient is 0, an increase in the asymmetry level of the potential well leads to an increase in the output voltage. Increasing the other parameters, the output voltage is reduced. In addition, as the uncertainty intensity increases, the parameter intervals of chaotic response become wider and the energy harvesting efficiency decreases. Moreover, as the potential well asymmetry increases, the sensitivity of energy harvesting system to uncertain parameter increases.

Advanced functionalities of Gd0.1Ta0.1Ti0.1O2 ceramic powder/P(VDF-TrFE) films for enhanced triboelectric performance

Triboelectric nanogenerator (TENG) had gained significant traction for their adeptness in converting diverse mechanical energies into electrical power. However, maintaining operational efficiency and stability amidst environmental temperature fluctuations had been a pressing concern. In this study, we addressed this challenge by leveraging Gd0.1Ta0.1Ti0.1O2(GTT) ceramic powder to engineer temperature-stable dielectric materials with heightened dielectric constants. These materials were seamlessly integrated with P(VDF-TrFE) to fabricate a composite thin film serving as the GTT-TENG triboelectric layer. The resultant GTT-TENG demonstrated remarkable electrical attributes, boasting an open-circuit voltage (VOC) of 134.6 V and a short-circuit current (ISC) of 3.75 μA, excellent P(VDF-TrFE) thin film-based TENGs. Notably, the relative change in VOC and ISC over a temperature range from −10°C to 180°C was recorded at 17.21% and 22.53%, respectively. Furthermore, the GTT-TENG showcased its capacity to concurrently power 60 LEDs, underscoring its versatility as a self-powered device. This study not only propelled TENG performance from a materials-centric standpoint but also alleviated its susceptibility to environmental temperature, thereby broadening its potential utility across diverse applications.

Study on the estradiol degradation gene expression and resistance mechanism of Rhodococcus R-001 under low-temperature stress

Estradiol (E2), an endocrine disruptor, acts by mimicking or interfering with the normal physiological functions of natural hormones within organisms, leading to issues such as endocrine system disruption. Notably, seasonal fluctuations in environmental temperature may influence the degradation speed of estradiol (E2) in the natural environment, intensifying its potential health and ecological risks. Therefore, this study aims to explore how bacteria can degrade E2 under low-temperature conditions, unveiling their resistance mechanisms, with the goal of developing new strategies to mitigate the threat of E2 to health and ecological safety. In this paper, we found that Rhodococcus equi DSSKP-R-001 (R-001) can efficiently degrade E2 at 30 °C and 10 °C. Six genes in R-001 were shown to be involved in E2 degradation by heterologous expression at 30 °C. Among them, 17β-HSD, KstD2, and KstD3, were also involved in E2 degradation at 10 °C; KstD was not previously known to degrade E2. RNA-seq was used to characterize differentially expressed genes (DEGs) to explore the stress response of R-001 to low-temperature environments to elucidate the strain's adaptation mechanism. At the low temperature, R-001 cells changed from a round spherical shape to a long rod or irregular shape with elevated unsaturated fatty acids and were consistent with the corresponding genetic changes. Many differentially expressed genes linked to the cold stress response were observed. R-001 was found to upregulate genes encoding cold shock proteins, fatty acid metabolism proteins, the ABC transport system, DNA damage repair, energy metabolism and transcriptional regulators. In this study, we demonstrated six E2 degradation genes in R-001 and found for the first time that E2 degradation genes have different expression characteristics at 30 °C and 10 °C. Linking R-001 to cold acclimation provides new insights and a mechanistic basis for the simultaneous degradation of E2 under cold stress in Rhodococcus adaptation.

Oxygen consumption rate during recovery from loss of equilibrium induced by warming, hypoxia, or exhaustive exercise in rainbow darter (Etheostoma caeruleum).

Animals routinely encounter environmental (e.g., high temperatures and hypoxia) as well as physiological perturbations (e.g., exercise and digestion) that may threaten homeostasis. However, comparing the relative threat or "disruptiveness" imposed by different stressors is difficult, as stressors vary in their mechanisms, effects, and timescales. We exploited the fact that several acute stressors can induce the loss of equilibrium (LOE) in fish to (i) compare the metabolic recovery profiles of three environmentally relevant stressors and (ii) test the concept that LOE could be used as a physiological calibration for the intensity of different stressors. We focused on Etheostoma caeruleum, a species that routinely copes with environmental fluctuations in temperature and oxygen and that relies on burst swimming to relocate and avoid predators, as our model. Using stop-flow (intermittent) respirometry, we tracked the oxygen consumption rate (MO2) as E. caeruleum recovered from LOE induced by hypoxia (PO2 at LOE), warming (critical thermal maximum, CTmax), or exhaustive exercise. Regardless of the stressor used, E. caeruleum recovered rapidly, returning to routine MO2 within ~3 h. Fish recovering from hypoxia and warming had similar maximum MO2, aerobic scopes, recovery time, and total excess post-hypoxia or post-warming oxygen consumption. Though exhaustive exercise induced a greater maximum MO2 and corresponding higher aerobic scope than warming or hypoxia, its recovery profile was otherwise similar to the other stressors, suggesting that "calibration" to a physiological state such as LOE may be a viable conceptual approach for investigators interested in questions related to multiple stressors, cross tolerance, and how animals cope with challenges to homeostasis.

Improving the environmental temperature adaptability of an electric temperature measurement subsystem by matching temperature coefficients of substitutable resistors

The electrical temperature measurement subsystem in space gravitational wave detectors requires micro-Kelvin precision in the submillihertz band. However, the low-frequency stability of the measurement circuit, excluding the sensor, is susceptible to environmental temperature fluctuations, closely related to the residual temperature coefficient of the circuit. This paper proposes a method to minimize the residual temperature coefficient for a thermistor-based temperature measurement , enabling the circuit to be mounted on surfaces with less stringent thermal stability requirements. Through extensive testing of resistors with the same nominal resistance, a best-matched pair is selected to compensate for the residual temperature coefficient by replacing two gain resistors in the low-pass filter. Our assessment demonstrates that this matching and replacement process reduces the residual temperature coefficient of the circuit from −0.135 mV K−1 to −0.027 mV K−1, resulting in a significant five-fold improvement in the subsystem’s adaptability to environmental temperatures within the specified frequency band. This method contributes to the development of measurement subsystems that meet stringent stability requirements.

Construction of a bearing capacity testing model for reinforced bridges based on material performance deterioration

Reinforced concrete beam bridges have been extensively utilized in transportation engineering due to their advantages such as simplified material selection and low cost. However, the mechanical performance of steel bars and concrete deteriorates over time due to factors such as prolonged bridge service life, fluctuations in environmental temperature and humidity, and other influences. To achieve a precise and effective prediction of the bearing capacity of reinforced concrete structures, this study proposes a method for assessing bearing capacity in the context of material performance degradation. The study commenced by examining the factors that impact the degradation of bridge performance and subsequently utilized material performance test values along with predicted and corrected values to estimate the reduced bearing capacity of the bridge. Additionally, the mechanical and bonding properties of modified reinforced concrete materials were calculated. The experiment results demonstrate that the calculated values from the modified model closely align with the measured values with a differential range of 0.06 to 0.38. At a micro level, nano-SiO2 modification enhances rubber concrete by improving the compactness of the matrix and enhancing bond strength between steel fiber-and-nanosilica-reinforced crumb rubber concrete and deformed steel bars. The revised model in this study exhibits excellent predictive capability for concrete strength, thereby enhancing the accuracy of outcomes in evaluating bridge technical conditions. This method holds potential for practical engineering applications and scientific research on bridge evaluation.

Investigating temperature-induced torque noise of a torsion pendulum based on temperature modulation at different frequencies.

Torsion pendulums are widely used for the measurement of small forces. In this study, we investigated the impact of temperature fluctuations on a torsion pendulum using heating devices to modulate the environmental temperature at different specific frequencies. The response coefficient between the temperature variation and the torque of the torsion pendulum was found to vary at different frequencies, with values from 4 × 10-15 N mK-1 at 0.1 mHz to 3 × 10-13 N mK-1 at 10 mHz. A passive thermal-insulation system was used to reduce the torque response within this frequency band, which is dominated by temperature noise. The results demonstrate that this modulation method provides a useful way to independently investigate the noise in a torsion pendulum resulting from environmental temperature fluctuations over a wide frequency band.

Seasonal Variation in the Thermoregulation Pattern of an Insular Agamid Lizard.

Ectotherms, including lizards, rely on behavioral thermoregulation to maintain their body temperature within an optimal range. The benign climate of islands is expected to favor the thermoregulation efficiency of reptiles throughout their activity period. In this study, we investigated the seasonal variation in thermoregulation in an insular population of the roughtail rock agama (Laudakia stellio) on Naxos Island, Greece. We measured body, operative, and preferred temperatures across three seasons (spring, summer, and autumn), and we evaluated the effectiveness of thermoregulation, using the Hertz index (E). Our results revealed that the effectiveness of thermoregulation was significantly influenced by seasonality. E was quite high in summer (0.97) and spring (0.92), and lowest in autumn (0.81). Accordingly, the quality of the thermal environment was significantly low during autumn, and maximum during summer. However, despite the environmental temperature fluctuations, lizards exhibited remarkable stability in body temperatures. They also adjusted their preferred temperatures seasonally and doubled the thermal niche breadth they occupied during summer, thus enhancing thermoregulation efficiency. Whether or not these adjustments are plastic or fixed local adaptations remains to be explored in further research across multiple years and seasons, including additional insular populations.

Microstructural characteristics evolution of asphalt mastics under cyclic environmental temperature variations

Environmental temperature-effect is the primary factor responsible for asphalt pavement failure. Asphalt pavement exposed to the atmosphere is constantly subjected to the thermal cycles induced by environmental temperature fluctuations, and the resulting thermal cracks significantly reduce the durability of asphalt pavement. Nevertheless, the influence of cyclic temperature variations on the performance degradation of asphalt binder materials is often overlooked. To address this, accelerated thermal cycling test was conducted on two asphalt mastics to simulate repeated environmental temperature variations. Dynamic shear rheological test (DSR) and atomic force microscopy test (AFM) were performed to characterize the evolution of the macroscopic rheological properties and microstructural characteristics under five cyclic temperature ranges. Pearson correlation analysis was utilized to explore the correlation between macro and micro properties. Following thermal cycling, it was observed that the two asphalt mastics experienced a decline in their viscous properties and became more elastic, resulting in a decrease in their stress relaxation capacity and asphalt-aggregate interaction on a macroscopic level. The microstructure transitioned from a multiphase to a homogeneous structure, while the expansion of the valley structure indicated the accumulation of microscopic defects. The larger the temperature variations and the higher the cyclic temperatures are, the more severe the deterioration in the viscoelasticity and microstructures of asphalt mastics is; the degradation of the micromechanical characteristics directly affects the macroscopic rheological properties. The bee structure ratio, the adhesion, and relaxation properties are sensitive to cyclic temperature variations and recommended to characterize the thermal cycling resistance. In comparison to 90# asphalt mastic, the SBS modified asphalt mastic exhibits great resistance to thermal deterioration. This study deepens the understanding of the causes of asphalt pavement performance deterioration in regions with frequent environmental temperature fluctuations.