Changes In Environmental Temperature Research Articles

Spectral Characteristics of Water-Soluble Rhodamine Derivatives for Laser-Induced Fluorescence.

We present a comprehensive fluorescence characterization of seven water-soluble rhodamine derivatives for applications in laser-induced fluorescence (LIF)techniques. Absorption and emission spectra for these dyes are presented over the visible spectrum of wavelengths (400 to 700nm). Their fluorescence properties were also investigated as a function of temperature for LIF thermometry applications. Rhodamine 110 depicted the least fluorescence emission sensitivity to temperature at -0.11%/°C, while rhodamine B depicted the most with a -1.55%/°C. We found that the absorption spectra of these molecules are independent of temperature, supporting the notion that the temperature sensitivity of their emission only comes from changes in quantum yield with temperature. Conversely, these rhodamine fluorophores showed no change in emission intensities with pH variations and are, therefore, not suitable tracers for pH measurements. Similarly, fluorescent lifetime, which is also a property sensitive to local environmental changes in temperature, pH, and ion concentration, measurements were conducted for these fluorophores. It was found that rhodamine B and kiton red 620 have shorter fluorescence timescales compared to those of the other five rhodamine dyes, making them least suitable for applications where temporal changes in emission are monitored. Lastly, we conducted experiments to assess the physicochemical absorption characteristics of these dyes' molecules into polydimethylsiloxane (PDMS), the most common material for microfluidic devices. Rhodamine B showed the highest diffusion into PDMS substrates as compared to the other derivative dyes.

Autonomous Thermal Modulator Based on Gold Film‐Coated Liquid Crystal Elastsomer

AbstractRadiative cooling has been recently intensively explored for thermal management and enhancing energy efficiency. Yet, traditional materials with singular emissivity fall short in dynamic thermal management, highlighting the need for materials that can adjust their thermal radiation in real time. Active modulation methods, requiring external stimuli such as mechanical stretch, electric potential, or humidity change, offer adaptability but can increase energy use and complexity. Passive approaches, using materials' inherent thermal‐responsive properties, face manufacturing and scalability challenges. Here, a scalable yet effective passive approach is introduced for adaptive thermal modulation based on gold (Au) and liquid crystal elastomer (LCE) with a reversible response to environmental temperature changes. This modulator enables a “low thermal resistance” state through actuation‐induced microcracks that expose a high‐emissivity polymer substrate, and a “high thermal resistance” state by closing these microcracks and forming a high thermal resistance air gap between the modulator and the target object. The flexible design and fixed external dimensions of the Au‐LCE thermal modulator make it adaptable to various surface geometries. Furthermore, by adjusting the LCE's chemical composition, the modulator's transition temperature can be tailored, broadening its applications from enhancing building energy efficiency to improving clothing thermal comfort.

FeverNet: Enabling accurate and robust remote fever screening

Remote human fever screening via thermal infrared imaging helps reduce the risk of respiratory disease transmission and plays an important role in public health monitoring. However, the accuracy of such systems often falls prey to variations in measurement distance and environment temperature. Most previous methods tend to employ sensors to overcome these variations, which are expensive schemes and have limited performance improvement. To address above problems, this paper presents a novel and robust remote fever screening framework named FeverNet. Specifically, FeverNet introduces depth estimation network and temperature distribution constraints across time periods to reduce the influence of distance variations and environment temperature changes. The fever attention module is thus proposed to enhance feature representation and expand the difference between fever faces and normal ones. In addition, we provide the Extended Thermal Infrared Face dataset (ETIF), which further gives visible images (paired with thermal infrared images) for depth estimation and improve the fever face generated method based on the maximum temperature of the face. Extensive experiments on ETIF demonstrate the advantages of our FeverNet over the state-of-the-art methods.

A temperature sensor based on multi-beam capture and interference

In this study, we proposed and validated a temperature fiber sensor based on optical signal capture Mach-Zehnder Interferometer (OSC-MZI) with high-precision temperature measurement capabilities. By creating three air cavities on a continuously offset-spliced no-core fiber (NCF), the optical signal experiences reflection and divergence within these cavities, which enhances the optical path of propagating light. Gradually, filling these NCF cavities with polymethyl methacrylate (PMMA) microspheres to increase the light coupling efficiency and as a sensing unit. Due to the directly contact between the optical fiber waveguide and PMMA, the state of incident lights is easily influenced by the refractive index (RI) variations of PMMA. When the environmental temperature changes, RI of the PMMA with high thermal-optic coefficient shows marked change, which finally leads to the obvious wavelength shift of interference dips in the transmission spectrum. Experimental results show that MZI coated with the polymer materials achieves a temperature sensitivity of up to 2.04 nm/°C within the temperature range of 25–50 °C. Furthermore, as an interference-based MZI sensor, its total length is only 4.75 mm. The proposed OSC-MZI provides a new approach for combining optical fiber sensors with polymer materials.

Влияние температуры на терморегуляцию и активность соболя (Martes zibellina L. 1758)

The purpose of the study is to identify the dynamics of thermoregulation and activity of the sable in the process of changing environmental temperature. Objectives: assessment of the dynamics of changes in the temperature of sable fur at positive and negative air temperatures; studying the dynamics of physical thermoregulation of sable due to convection and heat radiation; the influence of low air temperatures on the activity of the sable and the body’s costs of supporting vital functions. During long-term observations of sable activity, data were collected on the length of the animals’ daily movement in the Turukhansk and Evenk Districts of the Krasnoyarsk Region under accompanying weather conditions. Data on the dynamics of sable body temperature depending on the ambient temperature were collected in the Krasnoyarsk Flora and Fauna Park “Roev Ruchey”. The temperature period of the surface layer of air is covered from –30 to 30 °C. The pyrometer Testo 830-T1 was used. These studies expand and clarify ideas about the influence of the temperature factor on aspects of sable activity at low air temperatures in natural habitats. Analysis of data on the dynamics of physical thermoregulation of sable due to convection and heat radiation revealed temperature ranges of optimum for sable. Temperature optimum – 0 °C. The range of favorable temperatures for moving sable is from –5 to –25 °C. The largest number of sable tracks was recorded at a tempe¬rature of –15 °C. The data obtained make it possible to estimate the costs of the animal’s body to support vital functions during the winter period. At an air temperature of –15 °C, a sable in a calm state loses 2.78 Kcal per hour. Under favorable conditions, the predator spends 3 to 4 hours searching for food, losing 33,400 calories at a time.

A 1.65‐nW 11.14‐ppm/°C self‐biased subthreshold CMOS voltage reference with temperature compensation circuit

SummaryThis paper presents a subthreshold CMOS voltage reference (VR) that utilizes self‐biased circuits. This voltage reference includes temperature compensation circuits to expand its operating temperature range and reduce its temperature coefficient. The proposed CMOS voltage reference is designed using a standard 0.18‐μm CMOS process and has a small area of only 0.005 mm2. Post‐layout simulation results demonstrate that the power consumption of the circuit at room temperature (25°C) is only 1.65 nW at a power supply voltage of 1 V. In this case, the voltage reference output is 316.56 mV, with an average temperature coefficient (TC) of 11.14 ppm/°C in a wide temperature range from −40°C to 140°C. Furthermore, the line sensitivity (LS) of the circuit is 0.024%/V, and the power supply rejection ratio (PSRR) of the circuit is −86.5 dB at 10 Hz. In summary, the subthreshold CMOS voltage reference structure proposed in this paper demonstrates excellent performance characteristics, such as low power consumption, a small area, and high‐temperature stability. These features make it a promising candidate for voltage reference for low‐power applications with significant changes in environmental temperature.

Low temperature induces a significant decrease in auditory sensitivity of Xenopus laevis

ABSTRACT Temperature is a critical factor in shaping the physiological and metabolic processes of animals, notably impacting their auditory systems. Particularly, ectotherms face heightened vulnerability to temperature fluctuations. To comprehend the impact of rapid temperature changes on the auditory sensitivity of ectotherms, we measured the auditory sensitivity of Xenopus laevis at 10°C, 20°C, and 30°C respectively, using the auditory brainstem response. Our results reveal a significant decrease in auditory sensitivity of X. laevis at 10°C, with auditory thresholds markedly higher than those observed at 20°C and 30°C. Conversely, as the test temperature increased from 20°C to 30°C, their hearing sensitivity did not decline but tended to become more sensitive. In conclusion, our results suggest that rapid temperature changes have a discernible impact on the hearing sensitivity of X. laevis, particularly at low temperatures. These rapid environmental temperature changes significantly impact the sensory capabilities and courtship behaviours of animals, thereby influencing their population dynamics. Hence, revealing the consequences of rapid temperature fluctuations on sensory sensitivity in ectotherms is crucial for understanding the repercussions of climate change on animal population dynamics. These insights have profound implications for both environmental management and animal conservation.

Thermal parameter identification of concrete dams based on hybrid particle swarm optimization using distributed optical fiber monitoring data

The temperature of concrete arch dam during construction is affected by factors such as ambient temperature, cooling through water, and surface insulation. There is often a significant discrepancy between the actual thermal parameters and the values measured in indoor experimental tests. In this study, intelligent identification of thermal parameters is performed based on temperature monitoring data and an intelligence optimization algorithm so that the thermal characteristics of concrete in a real pouring environment can be obtained in real time. A hybrid algorithm of particle swarm optimization and grey wolf optimizer (HPSOGWO) is proposed. The performance of the hybrid particle swarm algorithm is verified to have some advantages over the other seven algorithms by twelve different test functions. Considering the influences of environmental temperature changes and multistage cooling water, HPSOGWO is utilized for inverse analysis of the thermal parameters of concretes with the same strength grade and concretes with different strength grades. The analysis results show that the concrete temperature values calculated based on the inversion of the HPSOGWO algorithm are in good agreement with the measured values, and the HPSOGWO algorithm has good adaptability in the inversion of thermal parameters of arch dams. The inversion results are of essential to clarify the relationship between temperature changes and thermal parameters.

Resource Scheduling Optimization of Fresh Food Delivery Porters Considering Ambient Temperature Variations

In the context of an evolving socio-economic landscape and rising living standards, the online market for fresh products, encompassing fruits, vegetables, meats, dairy, and eggs, has seen substantial growth, necessitating sophisticated logistics for e-commerce home delivery. This study tackles the distinct challenges of fresh product delivery, which demand rigorous adherence to climate conditions and product mix during transport, significantly influencing the operational strategies and scheduling of delivery platforms. To address these challenges, a comprehensive mathematical model was developed to optimize fresh food home delivery scheduling, focusing on reducing spoilage rates and accommodating the dynamic impact of environmental temperature changes. The model posits assumptions of a consistent and ample supply of fresh goods, standard initial quality loss, and efficient porter assignment for multi-category order combinations. It introduces three objective functions, targeting the minimization of fresh food loss, maximization of customer satisfaction, and reduction of distributor costs. The efficacy of the model and its genetic-algorithm-based solution method was assessed through numerical analysis and case studies, illustrating that the model enhances delivery efficiency and service quality across varying temperature conditions. This substantiates the critical role of environmental temperature management in optimizing fresh food delivery, offering a robust framework for advancing logistical operations in the perishable goods sector and ensuring quality and efficiency in fresh food e-commerce delivery.

HYPK: A marginally disordered protein sensitive to charge decoration

Intrinsically disordered proteins (IDPs) that lie close to the empirical boundary separating IDPs and folded proteins in Uversky's charge-hydropathy plot may behave as "marginal IDPs" and sensitively switch conformation upon changes in environment (temperature, crowding, and charge screening), sequence, or both. In our search for such a marginal IDP, we selected Huntingtin-interacting protein K (HYPK) near that boundary as a candidate; PKIα, also near that boundary, has lower secondary structure propensity; and Crk1, just across the boundary on the folded side, has higher secondary structure propensity. We used a qualitative Förster resonance energy transfer-based assay together with circular dichroism to simultaneously probe global and local conformation. HYPK shows several unique features indicating marginality: a cooperative transition in end-to-end distance with temperature, like Crk1 and folded proteins, but unlike PKIα; enhanced secondary structure upon crowding, in contrast to Crk1 and PKIα; and a cross-over from salt-induced expansion to compaction at high temperature, likely due to a structure-to-disorder transition not seen in Crk1 and PKIα. We then tested HYPK's sensitivity to charge patterning by designing charge-flipped variants including two specific sequences with identical amino acid composition that markedly differ in their predicted size and response to salt. The experimentally observed trends, also including mutants of PKIα, verify the predictions from sequence charge decoration metrics. Marginal proteins like HYPK show features of both folded and disordered proteins that make them sensitive to physicochemical perturbations and structural control by charge patterning.

Recyclable multifunctional ion conductive elastomers for strain/temperature sensors and bioelectrodes

Ionic conductive elastomers based on polymerizable deep eutectic solvents (PDES) have shown great application prospects in research fields such as lithium-ion batteries, smart soft materials, and wearable devices. However, most of these materials currently face the challenge of difficult recycling and reuse, resulting in environmental pollution and resource waste. In this work, we introduced PDES made of acrylic acid (AA) and choline chloride (ChCl) into polymerizable ionic liquid monomers [ATAC][TFSI] and prepared a physically crosslinked multifunctional ionic conductive elastomer PIL-PDES through a simple and rapid “one-step” photopolymerization strategy. This elastomer not only has satisfactory mechanical properties (tensile strength: 3.93 MPa, elongation at break: 760 %), high transparency (80 %), strong adhesion (iron: 135 kPa) and rapid self-healing but can also be recycled and reused. Based on the good conductivity of the elastomer (conductivity: 2.49 × 10−3 S/m), it can be used not only as a sensor to monitor human activities and changes in environmental temperature but also as a biological electrode to record human electrocardiogram signals. We believe that due to its superior overall performance and simple preparation method, PIL-PDES has broad potential for practical application in flexible wearable electronic devices.

Change of Natural Oscillation Frequencies of Buildings and Structures Depending on External Factors

Abstract —This work is devoted to the development of the engineering seismic monitoring method created in Geophysical Survey of the Russian Academy of Sciences (GS RAS). In previous years, the “method of standing waves” was created and put into practice. It helps to separate natural oscillation modes of buildings and other engineering structures. The natural oscillations of hundreds of various objects (buildings, bridges, dams, etc.) had been studied and identified. We assumed that the physical condition of studied constructions could be controlled during exploitation by measuring the changes of natural oscillation frequencies. That would help to identify the appearance of defects in constructions, to prevent the risk of their destruction. However, it turned out that not everything is that simple: changes in frequency values are logically affected by changes in the environment around the studied objects. This article provides examples of these relations, influence of changes in environmental temperature, mass of objects and precipitation on the frequencies of natural oscillations.

Diet effects on ectotherm thermal performance.

The environment is changing rapidly, and considerable research is aimed at understanding the capacity of organisms to respond. Changes in environmental temperature are particularly concerning as most animals are ectothermic, with temperature considered a key factor governing their ecology, biogeography, behaviour and physiology. The ability of ectotherms to persist in an increasingly warm, variable, and unpredictable future will depend on their nutritional status. Nutritional resources (e.g. food availability, quality, options) vary across space and time and in response to environmental change, but animals also have the capacity to alter how much they eat and what they eat, which may help them improve their performance under climate change. In this review, we discuss the state of knowledge in the intersection between animal nutrition and temperature. We take a mechanistic approach to describe nutrients (i.e. broad macronutrients, specific lipids, and micronutrients) that may impact thermal performance and discuss what is currently known about their role in ectotherm thermal plasticity, thermoregulatory behaviour, diet preference, and thermal tolerance. We finish by describing how this topic can inform ectotherm biogeography, behaviour, and aquaculture research.

Analysis of the Impact of Temperature Changes on the Productivity of Arabica Coffee Plants (Coffea arabica) Based on Coffee Farmer Adaptation Response

The productivity of coffee plants is highly dependent on changes in environmental temperature. This change caused several problems with its productivity, including: crop failure, decreased coffee bean quality, and decreased crop quantity. In addition, coffee farmers do not understand the impact it causes so that farmers are unable to make appropriate adaptation responses to the threat of changes in environmental temperature. This study aims to determine the impact caused by changes in environmental temperature on Arabica coffee plants based on the response of coffee farmers in Cipaganti village, Garut regency, Indonesia. The research method used is descriptive qualitative. Data collection was carried out using interviews, observation and documentation studies. Sampling using purposive sampling technique with the criteria of respondents who have their own land and have been farming for at least 5 years. The results showed that all farmers knew and felt changes in environmental temperature at the study site with an indicator of temperature rise. Changes in temperature have caused a decrease in productivity, a decrease in fruit quality, an increase in pest and disease attacks such as fruit borer, stem borer and leaf rust.

Comprehensive Investigation of the Temperature-Dependent Electromechanical Behaviors of Carbon Nanotube/Polymer Composites.

The performances of flexible piezoresistive sensors based on polymer nanocomposites are significantly affected by the environmental temperature; therefore, comprehensively investigating the temperature-dependent electromechanical response behaviors of conductive polymer nanocomposites is crucial for developing high-precision flexible piezoresistive sensors in a wide-temperature range. Herein, carbon nanotube (CNT)/polydimethylsiloxane (PDMS) composites widely used for flexible piezoresistive sensors were prepared, and then the temperature-dependent electrical, mechanical, and electromechanical properties of the optimized CNT/PDMS composite in the temperature range from -150 to 150 °C were systematically investigated. At a low temperature of -150 °C, the CNT/PDMS composite becomes brittle with a compressive modulus of ∼1.2 MPa and loses its elasticity and reversible sensing capability. At a high temperature (above 90 °C), the CNT/PDMS composite softens, shows a fluid-like mechanical property, and loses its reversible sensing capability. In the temperature range from -60 to 90 °C, the CNT/PDMS composite exhibits good elasticity and reversible sensing behaviors and its modulus, resistivity, and sensing sensitivity decrease with an increasing temperature. At room temperature (30 °C), the CNT/PDMS composite exhibits better mechanical and piezoresistive stability than those at low and high temperatures. Given that environmental temperature changes have significant effects on the sensing performances of conductive polymer composites, the effect of ambient temperature changes must be considered when flexible piezoresistive sensors are designed and fabricated.

Research on the adaptability of STF-Kevlar to ambient temperature under low-velocity impact conditions

Composite fabric formed by combining shear thickening fluid (STF) with aramid fabric (Kevlar) exhibits heightened impact resistance, rendering it extensively utilized within the realm of energy absorption. Given that composite fabrics often encounter various low-velocity impact scenarios in daily use, such as object falls, this study conducts rheological property tests and low-velocity impact experiments at different ambient temperatures to unveil the correlation between the low-velocity impact resistance of STF-Kevlar and environmental temperature. Rheological tests indicated that as temperature decreased, shear thickening behavior became more prominent, resulting in higher viscosity. Low-velocity impact tests demonstrated that with increasing temperature, the capability to withstand low-velocity impact gradually diminished in both STF and neat Kevlar, whereas the anti-impact property of STF-Kevlar increased. At a temperature of 60 °C, the peak load experienced by STF-Kevlar during low-velocity impact reached 1627 N, marking a notable 300% increase compared to the 407 N observed for neat Kevlar. Under changing environmental temperatures, alterations in the low-velocity impact resistance of STF-Kevlar were not contingent upon STF's viscosity but rather correlated with inter-yarn friction. The elevated inter-yarn friction at low temperatures hindered yarn sliding, leading to a decrease in the impact resistance of STF-Kevlar.

Physics-informed data-driven model of dehydration reaction stage in the sintering process of ternary cathode materials

The sintering process is the main process that affects the performance of ternary cathode materials. Due to the closed, continuous, and long-term characteristics of the sintering process carried out in a roller kiln, the reaction state including reaction degree, particle size, and etc., of the raw materials cannot be directly obtained through sampling detection, resulting in ineffective temperature control. This article mainly focuses on modeling the dehydration reaction stage of the sintering process to obtain the reaction state of the raw materials. Firstly, a two-sphere model is established based on Newton’s second law and the particle volume conservation equation to describe the relationship between the particle radius and sintering temperature of lithium hydroxide and ternary precursor; Secondly, the chemical kinetic parameters of the dehydration reaction in the two-sphere model are obtained by combining the single heating rate scanning method with the multiple heating rate scanning method; Then, in order to improve the accuracy of the two-sphere model and reduce the impact of external environmental temperature changes, a physics-informed neural network model is constructed by combining the two-sphere model with the neural ordinary differential equation model. Finally, the effectiveness of the modeling method is verified through numerical simulation and empirical data.

Novel baseline-free ultrasonic Lamb wave defect location method based on path amplitude matching

Ultrasonic Lamb wave detection technology constitutes a non-destructive evaluation approach extensively employed for the identification of flaws within plate-like structures. The conventional method for detecting and localizing defects in isotropic plate-like structures using ultrasonic Lamb waves relies on baseline signal data. However, the reliability of baseline data as a reference value is diminished due to varying working conditions of the structure. Therefore, to overcome the influence of mismatched baseline data, this paper proposes a novel non-baseline Lamb wave defect detection and localization method. Through simulation and experiment studies, it is discovered that defects at different positions have varied impacts on the amplitude of direct wave-packets under the same propagation path. By eliminating differences in the piezoelectric excitation characteristics of the sensing array (normalized through boundary reflect wave), the direct wave amplitude of multiple sensor pairs in the circular array can be compared and ranked. The paths closest to the location of the damage can be identified, enabling to obtain the defect location information. In this paper, the feasibility and effectiveness of this method has been verified by simulation and practical experiments. The experimental data and imaging results obtained over a four-month period demonstrate that, compared to the traditional baseline localization method, the baseline-free method proposed in this study exhibits a greater ability to resist interference caused by changes in environmental temperature. By increasing the number of sensors from 16 to 32, the positioning accuracy can be significantly improved, reducing the positioning deviation from 13 mm to 0.42 mm. This new non-baseline method based on path amplitude matching demonstrates enhanced practicality within the realm of engineering. Notably, this method holds the potential to be synergistically incorporated and applied in conjunction with various other measurement techniques.

A New Method for the Correction of Spectrum Drift Caused by Temperature Changes When Using a NaI(Tl) Seawater Radioactivity Sensor

The seawater radioactivity sensor based on the NaI(Tl) scintillation crystal detection method is prone to spectrum drift due to environment temperature changes during actual measurement, which pose difficulties in the activity analysis of seawater radionuclides. This paper adopts experiment design and analysis methods to study the relationship laws between temperature and peak position channel address and between gain and the peak position channel address. On the basis of studying and summarizing the two relationship laws of the NaI(Tl) seawater radioactivity sensor, a spectrum drift correction method combining gain adjustment and spectrum processing is proposed. Laboratory air and water environment experiments verify that the peak position channel address drift after air environment correction does not exceed ±2 channels, and after water environment correction does not exceed ±1 channel. Long-term verification experiments at the seawater work site have shown that this correction method can effectively correct the spectrum drift of the NaI(Tl) seawater radioactivity sensor and meet the requirements of long-term automatic operations at sea for the measured spectrum.

A new infrared radiation calibration method based on lens cover deduction of internal stray radiation

A new infrared radiation calibration method based on lens cover deduction of internal stray radiation is proposed to address the issue of grayscale deviation of infrared radiation measurement systems caused by environmental temperature changes, which leads to the failure of the traditional infrared radiation calibration method. Firstly, the influence of environmental temperature on the traditional radiation calibration was analyzed. Then, a mathematical model for infrared radiation calibration based on lens cover deducting internal stray radiation was established, and compared the environmental adaptability with the traditional radiation calibration. Finally, the experimental results show that this method has the ability to enhance the environmental adaptability of infrared radiation measurement systems, improve the accuracy of infrared radiation measurement, and especially for the optical system with high attenuation attenuator, the calibration coefficient can achieve the same environmental adaptability as that for the 100% transmittance attenuator. The environmental adaptability of the calibration coefficient is also greatly better than the traditional calibration for the 100% transmittance attenuator.