Temperature Changes Research Articles

"Grafting-to" Polymers of Xylan-g-allyl Glycidyl Ether Toughen PEG Hydrogel via Microphase Separation: Thermoresponsive and Photoreactive Molecular Assembly in DLP 3D Printing.

Utilizing naturally derived biopolymers in the macromolecular design of thermoresponsive polymers offers sustainable and biodegradable smart building blocks to functional materials. Here, a novel graft polymer of xylan-g-allyl glycidyl ether (xylan-g-AGE) that is thermoresponsive to self-assemble and photoreactive in photopolymerization is reported. This research highlights an innovative use of the debranched wood xylan, a chemically engineered linear polysaccharide of β-1,4-linked xylose, as the backbone in grafting polymer, which allows a greater degree of spatial coordination for sidechains than the analogous cellulose. Induced by the reformation of H-bonds and hydrophobic effect, xylan-g-AGE transits from solvated coil chain to self-assembled mesoglobules upon the temperature change above its lower critical solution temperature (LCST). When xylan-g-AGE is used in photoresins to fabricate hydrogels with good geometric fidelity via DLP 3D printing, solvated xylan-g-AGE stiffens the polyethylene glycol (PEG) hydrogel strongly, due to higher crosslink density of available AGE moiety and faster crosslinking rate, while self-assembled xylan-g-AGE toughens the PEG hydrogel better, attributed to the strategy of "dual chemically independent domains" that smartly combines tough domain of PEG and soft domain of self-assembled xylan-g-AGE. Conductive hydrogel is fabricated by incorporating 2D MXene sheets into this hydrogel matrix in DLP printing, which demonstrates superior performance as wearable strain sensors.

Thermal Threshold for Localized Blood-Brain Barrier Disruption.

The Blood-Brain Barrier (BBB) is the gatekeeper of the central nervous system, effectively shielding the brain from blood-borne threats but simultaneously representing a significant challenge for treating neurological diseases. Altering the permeability of the BBB enables increasing the local drug concentration enhancing therapeutic effects. This study aims to explore the BBB permeability alteration through localized mild temperature increases, addressing the challenge of accurately determining and monitoring thermal dosages during hyperthermia treatments. To investigate the BBB permeability alteration, an infrared laser was used applying minimal thermal doses in a highly localized manner. The necessary threshold temperature for opening the BBB was determined in rats. In an exploratory rat study, noninvasive techniques, such as dynamic contrast enhancement-magnetic resonance imaging and magnetic resonance thermometry, were employed to show and monitor the effective BBB permeability alteration and the thermal dosage. Post-mortem verification was performed using Evan's Blue dye to assess BBB disruption. The study found that a localized increase in brain temperature of approximately 6 K (from a baseline of 37 °C to 43 °C) was sufficient to effectively disrupt the BBB. This temperature threshold was verified in-vivo and was consistent with post-mortem findings from the Evan's Blue extravasation method. The findings demonstrate that BBB permeability can be altered and controlled by applying minimal, localized thermal doses improving the delivery of therapeutics to the brain. Noninvasive imaging techniques such as DCE-MRI and MRT offer precise monitoring of the temperature changes required for BBB disruption enabling better control over thermal dosages.

Conductive Heat Flux Over Arctic Sea Ice From 1979 to 2022

Abstract The conductive heat flux (CHF) from the ocean to the snow/sea ice‐atmosphere interface through sea ice is a crucial component of the surface energy budget over the sea ice‐covered Arctic Ocean. The CHF is influenced by surface skin temperature, sea ice thickness, and depth of snow on sea ice. This study uses monthly mean surface skin temperature from ERA5 reanalysis, and sea ice thickness and snow depth from the Pan‐Arctic Ice‐Ocean Modeling and Assimilation System to derive the means and changes of CHF over the Arctic Ocean from 1979 to 2022. The findings reveal that CHFs are generally positive (from flux to the surface from below) from November to March and negative from June to August. CHFs are large in peripheral seas with thin sea ice and low snow depth, and small over pack ice with thick sea ice and snow. The thinning of sea ice and snow on sea ice contributes to increasing CHF, while rising surface skin temperatures lead to decreasing CHF. Overall, CHF increases from 1979 to 2022, primarily driven by the thinning of sea ice. The magnitude of CHF changes during this period is comparable to or higher than those in sensible heat flux, latent heat flux, and net longwave/thermal radiation flux at the surface from November to March over the peripheral seas. A better representation of sea ice thickness and snow depth over sea ice in the reanalysis would possibly improve the depiction of CHF and surface temperature changes.

Do males and females with matched body size/composition possess comparable physiological and perceptual responses in transient neutral-cool environments?

Do males and females with matched body size/composition possess comparable physiological and perceptual responses in transient neutral-cool environments?

The Eye-Opening Arbiter-PUF FPGA Implementation with Auto Error Detection

We present the first implementation of an FPGA-based PUF that leverages the usually contradictory requirements of stability and response time. Many state-of-the-art implementations of PUFs are either slow with a low error rate, like the ring oscillator-PUF, or fast with a higher error rate, like the arbiter-PUF. The presented implementation of an eye-opening PUF uses the phase-integrating effect of a ring oscillator to realize the shortest possible response for the required stability of the readout. This principle also allows for new automatic detection of unstable bits based on counting the number of oscillations required until an arbitration is conducted. This first implementation of an eye-opening PUF reduces the bit error rate to a number under our measurement limits, while the readout time is simultaneously kept as low as ≤1.54 μs, with an average of 0.85 μs. In addition, environmental temperature changes are evaluated, and methods for limiting these effects are discussed.

Combining scientific and local knowledge to understand climate change effects in high mountains: A case study from Porshinev Jamoat, Tajikistan

Abstract While climate change is widely recognised to threaten livelihoods and sustainable development, communities at high altitudes are some of the most vulnerable because of their low adaptive capacity and fragile environment. The Pamir has already experienced climate uncertainties given that this is the poorest, most marginalised and least developed region of Tajikistan. Changes in weather patterns and hydrological cycles create challenges for local farmers who depend on a high level of subsidised agriculture. Due to sparse instrumental data, as well as the low accuracy of climate models in this mountainous area, current local climate trends are poorly understood. To address these challenges, a combination of local knowledge with scientific data is a viable option. Here we analysed 84 years of air temperature and precipitation data and conducted semi‐structured interviews with local farmers. Average annual air temperature increased significantly during this period, with winter and spring temperatures significantly increasing; insignificant increasing trends were observed during summer and autumn. During winter and spring, only May did not experience significant temperature increases. Precipitation exhibited a gradual (but insignificant) decline of about 46 mm during the 84‐year period in a region where annual precipitation is about 250–300 mm. Precipitation decreased in winter and spring and increased in summer and autumn. This shift affects the ratio between solid and liquid precipitation and reflects a decrease in snow‐pack accumulation in the mountains, which decreases water availability. The shift of the rainy season to summertime decreased the local thermal regime and affected crop maturation. Local farmers' perceptions correlated well with the mean and seasonal precipitation changes and mean and winter air temperature changes. Discrepancies between perceptions and actual data occurred related to summer temperature change; 46% of respondents perceived a change in annual temperature, 56% perceived an increase in winter and 71% a decrease in summer temperature. For precipitation, 77% reported a change in annual precipitation, 80% a decrease in winter precipitation and 54% an increase in summer precipitation. Changes in annual air temperature and precipitation affect the growing season and plant maturation time and therefore bring uncertainties to local cropping systems.

Thermal Hysteresis and Reversibility of the Giant Magnetocaloric Effect at the Ferromagnetic Transition of Nd2In.

The Nd2In compound exhibits an intriguing borderline first-/second-order transition at its Curie temperature. Several studies have pointed to its potential for magnetic cooling, but also raised controversies about the actual order of the transition, the amplitudes of the hysteresis, and of its magnetocaloric effect. Here, we estimate the thermal hysteresis using magnetic and thermal measurements at different rates. It is found to be particularly small (0.1-0.4 K), leading to almost fully reversible adiabatic temperature changes when comparing zero-field cooling and cyclic protocols. Some open questions remain with regard to the magnetostriction of Nd2In, which is presently found to be limited, in line with the absence of a thermal expansion discontinuity at the transition. The comparison of the magnetocaloric effect in Nd2In and Eu2In highlights that the limited saturation magnetization of the former affects its performance. Further efforts should therefore be made to design materials with such borderline first-/second-order transitions using heavier rare earths.

The mixing characteristics of natural gas and hydrogen based on the Soave–Redlich–Kwong equation of state

This study investigates the blending characteristics of natural gas (NG) and hydrogen in a Kenics static mixer using computational fluid dynamics. The effectiveness of the adopted numerical model is experimentally validated. The scenario of high-pressure, long-distance NG pipelines is considered, and the Soave–Redlich–Kwong equation of state is applied. The mixing uniformity and pressure loss are adopted as evaluation criteria to analyze the impact of factors such as the deflection angle of spiral blades, the number of blades, the length-to-diameter ratio, the hydrogen blending ratio (HBR), the pipeline pressure, and the temperature on mixer performance, followed by structural optimization of the mixer. It is found that a Kenics static mixer with two spiral blades, a length-to-diameter ratio of 2, and a deflection angle of 135° can achieve a mixing uniformity of 95% at the blade outlet while minimizing pressure loss. Increasing the HBR helps improve the mixing uniformity but also increases the pressure loss of the mixer. Increasing the pipeline pressure while keeping the hydrogen mole fraction constant enhances the mixing uniformity but also increases the pressure loss. Increasing the gas temperature reduces the mixing uniformity and the pressure loss. Overall, pipeline pressure and temperature changes have a minimal impact on the mixing characteristics. Under high-pressure conditions, the use of a real gas model is essential. This study provides theoretical guidance for the design of static mixers for hydrogen blending in high-pressure NG pipelines.

Effects of climate change on stream temperature and salmonid habitats in a Cascades river basin.

Effects of climate change on stream temperature and salmonid habitats in a Cascades river basin.

Environmental effect analysis of temperature-induced mounting failures in electronic products

Abstract The test product showed many signs of a nonlinear jump regarding output voltage during the temperature cycle test. After the components were analyzed, the parameter jump was found to be caused by the nonlinear jump of the terminal resistance. A microdefect with a thickness of about 1 μs was discovered between the plating and substrate of the faulty sample by comprehensively using methods such as metallographic sampling, micromorphology imaging, and energy spectrum analysis techniques during the environmental effect analysis. The analysis shows that the primary cause of the resistance jump is the binding defect between the plating and the substrate. The difference between expansion coefficients of different materials and the effect of the thermal stress cause cracking between plating layers and a change in the contact area between the terminal substrate and the plating/solder layer, making this component show abnormal electrical characteristics during temperature change.

Physiology of athletes

Sports equipment is crucial in achieving athletic performance by providing comfort, flexibility, and support during physically demanding activities. Its functionality not only enhances athletes' performance but also helps maintain body temperature and comfort, allowing athletes to fully dedicate themselves to sporting challenges. This research focuses on sportswear, specifically football jerseys, emphasizing the importance of comfort. By analysing the thermal properties of football jerseys, the study aims to better understand the effects of clothing on thermal comfort during different phases of activity. Using an infrared thermographic camera and recording images of the participants before and after intense activity, zones of sweating and temperature changes are identified. The results of the study provide guidelines for the behaviour of athletes in sportswear made of three different materials. The results should also serve to improve the development of sportswear to better meet the needs of athletes and increase their comfort and performance.

Simulating stepwise depressurization production of natural gas hydrate using a three-dimensional test system

In the three-dimensional scale, the gas hydrate reservoir can be more accurately simulated, and on this basis, the stepwise depressurization production characteristics study can provide a scientific basis for improving the efficiency and controllability of gas hydrate production. This study used a three-dimensional gas hydrate production simulation device to conduct stepwise depressurization production tests with a single horizontal well in three-dimensional scale. The results were compared with two-dimensional tests to investigate the effects of reservoir scale and stepwise depressurization on hydrate production characteristics and efficiency. The results showed that in the early stage of depressurization, free gas production dominated, and the pressure change rate was easy to control. However, in the middle and late stages, hydrate decomposition led to more complex pressure changes. Compared to the two-dimensional tests, the Joule–Thomson effect had a more significant impact on temperature changes in the three-dimensional tests, making temperature stratification more noticeable than pressure stratification. The cumulative gas production in the three-dimensional tests was only 7.2 times that of the two-dimensional tests, which may be attributed to the combined effects of reservoir heterogeneity, low heat transfer efficiency, complex gas migration pathways, and dynamic changes in pore structures, all of which reflect the inherent complexity of hydrate production in realistic geological conditions, characterized by nonlinear production behavior and strong coupling among thermal, hydraulic, mechanical, and chemical fields. The average gas production rate changed in stages over time, with higher rates during depressurization and lower rates during constant pressure. Unlike the two-dimensional tests, the gas production capacity gradually weakened in the three-dimensional tests, aligning more closely with real-world conditions. The peak gas production rate showed a sequential change trend throughout the test, reflecting the system's dynamic behavior.

Dependence of the conversion efficiency of CIGS solar cells on the incident laser wavelength for optical wireless power transmission

Abstract CIGS solar cells for optical wireless power transmission (OWPT) were irradiated with four lasers having a wavelength of 635 nm, 850 nm, 1064 nm, and 1208 nm. We investigated the dependence of conversion efficiency on the incident laser intensity and device temperature. The highest conversion efficiency was 30.3 % when irradiated with a 1064 nm light with 0.18 W/cm2, followed by 850 nm, 635 nm, and 1208 nm, in that order. The conversion efficiencies decreased with a temperature change from 20°C to 60°C, with the rate of decrease being the smallest at 1064 nm and the largest at 635 nm.

2D Ruddlesden–Popper X-FPEA2PbI4 perovskites for highly stable PeLED with improved opto-electro-mechanical properties

We investigate the opto-electro-mechanical characteristics and stability of Ruddlesden–Popper X-FPEA2PbI4 perovskites, where X represents para (p), meso (m), and ortho (o) configurations. The findings reveal that the transition from para to meso and ortho configurations results in a progressive increase in the bandgap, with values of 2.097 eV, 2.133 eV, and 2.177 eV, respectively. Notably, p-FPEA2PbI4 exhibits superior stability, characterized by an enhanced formation energy of − 4.825 eV, compared to m-FPEA2PbI4 (− 4.647 eV) and o-FPEA2PbI4 (− 4.581 eV). Thus, p-FPEA2PbI4 emerges as a leading candidate for the active layer in perovskite light-emitting diodes (PeLEDs). Internal quantum efficiencies of 6.289% for PEA2PbI4 and 2.285% for p-FPEA2PbI4 have been achieved, both of which are higher than those of MAPbI3. In contrast, the dependence of efficiency on temperature fluctuations for p-FPEA2PbI4 is 0.01 1/K, compared to PEA2PbI4’s 0.0282 1/K, highlighting its enhanced stability under temperature changes. Furthermore, the stability of the emission spectrum against temperature fluctuations for p-FPEA2PbI4, with a value of 0.0156 nm/K, is greater than that of PEA2PbI4, which has a value of 0.0245 nm/K. Although the efficiency of PeLEDs utilizing p-FPEA2PbI4 is somewhat lower than that of PEA2PbI4, its superior stability makes it a compelling choice for future applications, paving the way for more reliable and durable light-emitting devices.

Detection of gamma irradiation with milligray resolution using a slow-light fiber Bragg grating.

For many medical and safety applications, it is important to develop fiber sensors that can detect very low doses of gamma radiation (mGy) with integration times of 1 s or shorter. Here, we describe a sensor based on a new calorimetric technique that we believe is one of the most sensitive and compact reported to date. The fiber subjected to irradiation has a silica core doped with Ce-doped lutetium aluminum garnet nanocrystals selected to achieve a strong radiation-induced absorption (RIA). Light launched in the irradiated fiber is absorbed by RIA, the fiber heats up, and the temperature change is measured with a slow-light fiber Bragg grating (FBG) placed in physical contact with it. Thanks to the doped fiber's large RIA, and the excellent resolution (mK/√Hz) and low drift (a few mK/min) of the slow-light sensor, with 1.2 W of excitation power at 1040 nm, this sensor has a very low detection limit of ∼6 mGy/√Hz. Thanks to the use of a short FBG (7 mm), it is also extremely small. With straightforward improvements, the detection limit can be reduced to sub-mGy/√Hz. For in situ measurements, this technique can also be easily extended to use the slow-light FBG itself as the radiation sensor.

Triaxial accelerometers and subcutaneous biologgers as tools to record diurnal and nocturnal changes in locomotor activity, body temperature, heart rate, and heart rate variability in melatonin-treated lambs (Ovis aries).

Triaxial accelerometers and subcutaneous biologgers as tools to record diurnal and nocturnal changes in locomotor activity, body temperature, heart rate, and heart rate variability in melatonin-treated lambs (Ovis aries).

Thermal Effects on Fines Migration: Insights from Sand Pack Experiments

Mobilisation of in situ fine particles within oil sands reservoirs plays a critical role in permeability reduction and pore throat blockage, ultimately impairing reservoir performance and diminishing well productivity during thermal recovery operations. Variations in reservoir fluid conditions, such as changes in salinity and temperature, trigger the detachment, transport, and redeposition of fines within porous media. This study introduces a novel high-pressure high-temperature (HP-HT) sand retention testing (SRT) facility designed for evaluating formation damage by fines migration in SAGD producer wells, under salinity change and elevated temperature conditions. Such an integrated approach accounting for conditions closer to near-wellbore SAGD producers has not been explored in previous SRT methodologies. Laboratory tests were conducted on synthetic sand mixtures replicating the particle size distribution (PSD) and sand composition of the McMurray Formation, packed over a slotted liner coupon as a common sand control device used in SAGD producer wells. Produced fines concentration analysis, permeability measurements, and post-mortem retention profile analysis were employed to explain the fines transport mechanisms. The results highlighted the influence of repulsive electrostatic forces in mobilising, transport mechanisms and retention of fine particles at elevated temperature and low salinity conditions. The findings of this paper provide a deeper understanding of fines migration in SAGD reservoirs, delivering insights for optimising field strategies to mitigate fines-related flow restrictions and enhance bitumen recovery efficiency.

The impact of ambient air pollution and meteorological factors on emergency hospital admissions of COPD patients in Poland (2012–2019)

The relations between ambient air pollution, meteorological factors, and the number of emergency hospital admissions due to chronic obstructive pulmonary disease (COPD) were analyzed. The study utilized a nationwide collection of emergency hospital admissions from anonymous public registries covering the period of 8 years (2012–2019). Separated analyses were presented by sex, age group, and place of residence (rural vs. urban area), a group of major pollutants (PM2.5, PM10, SO2, NOx, and NO2), and meteorological factors (daily air temperature minimum (Tmin), air temperature maximum (Tmax) and the daily change of an average air temperature (dTc), relative humidity (Rh) and wind speed (Ws)). This analysis confirmed association between environmental factors and an increase in the number of emergency hospital admissions of COPD patients. The greatest correlations (p < 0.001) were r = 0.58 and day lag = 5 days for PM10, r = 0.63 and day lag = 20 days for PM2.5, r = 0.73 and day lag = 20 days for SO2, r = 0.57 and day lag = 25 days for NO2 and r = 0.51 and day lay = 30 for NOx as well as r = -0.78 and day lag = 19 days for Tmax, r = -0.79 and day lag = 19 days for Tmin, r = − 0.57 and day lag = 22 days for dTc, r = 0.42 and day lag = 30 days for Rh and r = 0.40 and day lay = 14 for Ws. Variations of SO2 and temperature were the most important factors associated with emergency hospital admissions of COPD patients in Poland. Women, patients aged 60–79 as well as inhabitants of urban areas showed stronger and faster responses to changes in environmental elements.

Identifying Wet Troposphere Delay in L‐Band InSAR Using Weather Radar Reflectivity

Abstract Synthetic Aperture Radar (SAR) pulses undergo variable propagation delays in the atmosphere due to changes in pressure, temperature, and humidity within the troposphere, causing large error in Interferometric SAR (InSAR) measurements of land surface displacement. Wet troposphere delay, resulting from condensed water and water vapor clouds, can introduce delays of tens of centimeters that significantly impact surface displacement estimates. This study provides unequivocal evidence of the wet troposphere's impact on InSAR phase measurements by examining spatial patterns in NOAA NEXRAD weather radar reflectivity and interferometric phase outliers. We utilize a feature‐comparison approach with reflectivity data from NEXRAD radar stations to identify artifacts from wet tropospheric delays in InSAR phase measurements derived from rapid repeat‐pass data acquired by UAVSAR L‐band SAR. NEXRAD's 5‐min scanning interval, compared to UAVSAR's 30‐min revisit time, enabled detection of phase artifacts caused by fast‐moving and developing clouds. We identify regions in InSAR interferograms with troposphere‐induced phase artifacts by matching features common to InSAR phase outlier masks and NEXRAD high reflectivity masks. Matched results between InSAR phase noise and NEXRAD reflectivity show phase delays of up to 25 radians in L‐band, corresponding to 48 cm of delay. Comparison with tropospheric delays calculated using the Generic Atmospheric Correction Online Service for InSAR (GACOS) showed global weather models lack sufficient spatial and temporal resolution to accurately estimate observed wet troposphere delays. While our study focused on UAVSAR, findings apply to other SAR missions, including L‐band NISAR and ALOS2/4, aiding identification and interpretation of InSAR results affected by tropospheric delays.

Biodistribution and long-term toxicity of neutron-activated Samarium-153 oxide-loaded polystyrene microspheres in healthy rats.

Biodistribution and long-term toxicity of neutron-activated Samarium-153 oxide-loaded polystyrene microspheres in healthy rats.