Low Thermal Sensitivity Research Articles

An Ultra-low Thermal Sensitivity Drift Piezoresistive Pressure Sensor Compensated by Passive Resistor/Thermistor Network

This paper presents a piezoresistive pressure sensor that exhibits extremely low thermal sensitivity drift across a broad range of temperatures, which integrates a passive resistor/thermistor network for compensation. Standard microfabrication processes were conducted to fabricate the sensor chip. From the experimental results, the proposed sensor demonstrated an extremely low thermal sensitivity drift of 0.01% FS/°C within temperature range of -55 °C to 85 °C, which is a significant improvement compared with the sensor with no temperature compensation (0.17% FS/°C) and the sensor with conventional temperature compensation (0.09% FS/°C). The compensation method developed in this study has the potential to serve as a facilitating instrument in pressure measurements with large temperature variations.

Experimental study on thermo-physiological differences between children and adults during indoor sedentary conditions

Previous research has shown that children prefer cooler environments and have lower thermal sensitivity than adults. This disparity may be attributed to physiological differences between these age groups. However, studies are scarce that specifically measure children's physiological parameters. In this study, we measured the physiological parameters of children aged 6–9 years and their parents, concurrently collecting their thermal comfort votes. Measured physiological parameters include metabolic rate, blood flow, body composition, core temperature, blood oxygen, heart rate, skinfold thickness, and skin temperature.We found that the average metabolic rate of the measured children was 1.20 met, 39% higher than the measured adults who had their average metabolic rate as 0.86 met. Children consistently exhibited higher metabolic rates than their own parents. Children were observed to have less body fat and thinner skin folds compared to adults. Additionally, children exhibited higher skin temperatures in core areas, elevated heart rates, and quicker recovery of skin blood flow and local skin temperature after experiencing cold exposure on hand compared to adults. These characteristics reveal children's superior thermoregulatory abilities, explaining their preference for cooler environments and reduced thermal sensitivity. Besides, no gender difference was observed in the thermal physiology of the measured children.All of the distinctive thermal physiological traits of children underscore the necessity of specific criteria for evaluating the thermal comfort of children.

Ultrasensitive NIR-II Ratiometric Nanothermometers for 3D In Vivo Thermal Imaging.

Luminescent nanothermometry, particularly the one based on ratiometric, has sparked intense research for non-invasive in vivo or intracellular temperature mapping, empowering their uses as diagnosis tools in biomedicine. However, ratiometric detection still suffers from biased sensing induced by wavelength-dependent tissue absorption and scattering, low thermal sensitivity (Sr ), and lack of imaging depth information. Herein, this work constructs an ultrasensitive NIR-II ratiometric nanothermometer with self-calibrating ability for 3D in vivo thermographic imaging, in which temperature-insensitive lanthanide nanocrystals and strongly temperature-quenched Ag2 S quantum dots are co-assembled to form a hybrid nanocomposite material. Precise control over the amount ratio between two sub-materials enables the manipulation of heat-activated back energy transfer from Ag2 S to Yb3+ in lanthanide nanoparticles, thereby rendering Sr up to 7.8% °C-1 at 43.5 °C, and higher than 6.5% °C-1 over the entire physiological temperature range. Moreover, the luminescence intensity ratio between two separated spectral regions within the narrow Yb3+ emission peak is used to determine the depth information of nanothermometers in living mice and correct the effect of tissue depth on 2D thermographic imaging, and therefore allows a proof-of-concept demonstration of accurate 3D in vivo thermographic imaging, constituting a solid step toward the development of advanced ratiometric nanothermometry for biological applications.

Numerical study on the effects of viscous heating and random rough surface on cavitating flow in fuel injection nozzles

A transient numerical model was developed to investigate cavitating flow in fuel injection nozzles, incorporating the effects of viscous heating and latent heat of phase change. A three-dimensional Gaussian rough surface generated by Monte Carlo simulation was compared to a wall function correction-based roughness model to assess the impact of surface roughness on both flow and thermal fields. Results demonstrated that viscous heating increased fuel temperature significantly near the nozzle wall, whereas latent heat had minimal effect due to the diesel fuel's low thermal sensitivity. The random rough surface performed better than the wall function correction-based model in inducing local cavitation, reflecting sub-micron scale roughness, and revealing significant randomness in velocity, temperature, and cavitation fields. Roughness height and correlation length were found to be critical factors characterizing surface roughness, where an increase in roughness height and a decrease in correlation length predicted a rougher surface and enhanced effect of viscous heating. The ratio of these two parameters showed a clear linear relationship with temperature rise. Geometric and localized cavitation were observed, leading to temperature increases caused by cavity evolution and collapse. These insights are valuable for improving fuel atomization and combustion efficiency.

Utilizing Energy Transfer in Mn2+/Ho3+/Yb3+ Tri-doped ZnAl2O4 Nanophosphors for Tunable Luminescence and Highly Sensitive Visual Cryogenic Thermometry.

Lanthanide (Ln3+)-doped upconversion (UC) phosphors converting near-infrared (NIR) light to visible light hold very high promise toward biomedical applications. The scientific findings on luminescent thermometers revealed their superiority for noninvasive thermal sensing. However, only few reports showcase their potential for applications in extreme conditions (temperatures below -70 °C) restricted by low thermal sensitivity. Here, we demonstrate the tailoring of luminescence properties via introducing Ho3+-Mn2+ energy transfer (ET) routes with judicious codoping of Mn2+ ions in ZnAl2O4/Ho3+,Yb3+ phosphor. Preferentially, a singular red UC emission is required to improve the bioimaging sensitivity and minimize tissue damage. We could attain UC emission with 94% red component by a two-photon UC process. Higher temperature annealing brings the color coordinates to the green domain, highlighting the potential for color-tunable luminescence switch. Moreover, this work investigates the thermometric properties of ZnAl2O4/Yb3+, Ho3+ in the range of 80-300 K and influence of inducing extra ET pathways by Mn2+ codoping. Interestingly, the luminescence intensities for nonthermally coupled (5F4,5S2) and the 5F5 radiative transitions of Ho3+ ions display opposite behavior at 80 and 300 K, which revealed competition between temperature-sensitive decay pathways. The codoping of Mn2+ ions is fruitful in causing a fourfold increase of absolute sensitivity. Notably, the color tunability from green through yellow to red is helpful in rough temperature estimation by naked eyes. The maximum relative (Sr) and absolute sensitivities (Sa) were estimated to be 1.89% K-1 (140 K) and 0.0734 K-1 (300 K), respectively. Even at 80 K, a Sa of 0.00447 K-1 and Sr of 0.6025% K-1 were achievable in our case, which are higher than most of the other Ln3+-based systems. The above-mentioned results demonstrate the potential of ZnAl2O4/Yb3+,Ho3+ for cryogenic optical thermometry and a strategy to design new Ln3+-based UC thermometers by taking advantage of ET routes.

Support-Free Thermally Insensitive Hollow Core Fiber Coil

Light traversing an optical fiber is subject to various local phase perturbations driven by temperature. This thermal phase sensitivity is undesirable in fiber interferometers and their applications which require that a fixed, stable phase be received after propagation. The use of hollow core fiber (HCF) has been shown to reduce this thermal phase sensitivity over solid core fibers and here we propose and demonstrate how coiling HCF to a prescribed geometry can further significantly reduce this sensitivity. Our proof-of-concept experiment shows reduction by a factor of ∼90 with respect to the uncoiled HCF, and over three orders of magnitude with respect to uncoiled solid core optical fiber. Our strategy exploits a nuance of the elastic properties of fiber coils whereby the constrained thermal expansion of the composite material (fiber + coating) can result in a coil having compressed inner layers and expanded outer layers. Thermal expansion is the dominant effect responsible for thermal phase sensitivity in HCFs, and in this scheme the compressed inner coil layers compensate the thermal expansion of the outer layers. In this study we design the coil parameters using finite element simulations, studying the relationship between coil performance and its key parameters. The proof-of-principle coil has 160 mm diameter and incorporates a 548 m length of HCF out of which a 230 m section shows almost zero (slightly negative) thermal phase sensitivity. Though the coil shows low thermal phase sensitivity over tens of hours, the long-time constant viscoelastic properties of the coating materials used in the HCF under study are shown to limit these benefits. To make this strategy practical for systems with fast temperature dynamics, a coating having more stable mechanical properties could be used. For precision timing systems in which long thermal time constants are already the norm, this scheme represents a low-cost and provides a significant reduction to thermal sensitivity which is immediately practicable.

Stabilising effects of karstic groundwater on stream fish communities

AbstractAlthough groundwater exchange processes are known to modulate atmospheric influences on stream temperature and flow, the implications for ecological stability are poorly understood. Here, we evaluated temporal change in stream fish communities across a gradient of groundwater influence defined by karst terrain (carbonate parent materials) within the Potomac River basin of eastern North America. We surveyed 12 sites in 2022 that had been sampled 29–30 years previously with similar methods. We also collected stream temperature data from each site and used the regression slope of the air‐water temperature relationship to index stream thermal sensitivity and groundwater exchange processes. Sites in karst terrain exhibited strong groundwater controls on stream temperature, and fish communities were more stable over time in these locations than elsewhere. However, stream thermal sensitivity was a stronger predictor of species persistence than the spatial distribution of karst terrain in contributing areas, highlighting the ecological importance of local variation in groundwater discharge processes. The presence of calcium precipitates (marl) in stream substrates was associated with low thermal sensitivity and ecological stability over time, and we suggest such visible features may be a useful indicator of climate change refugia in stream ecosystems.

Fully Integrated Solid-State LiDAR Transmitter on a Multi-Layer Silicon-Nitride-on-Silicon Photonic Platform

We report a LiDAR transmitter incorporating both a hybrid-integrated tunable external cavity laser and a high-resolution 2-D optical phased array beam-steerer. Widely tunable single-mode lasing over a span of approximately 100 nm is achieved with >42 dB side-mode-suppression-ratio, 18 mW output power, and 2.8 kHz linewidth. Two-dimensional beam steering in a field-of-view of 140° × 16° exhibits a beam divergence of 0.051° × 0.016° measured in full width at half maximum. Leveraging the low propagation loss, negligible nonlinear loss, and low thermal sensitivity of silicon nitride, and combining the high mode confinement and efficient thermal tuning of silicon, the device affirms the feasibility of high-power on-chip lasing, power bottleneck elimination, and low on-chip insertion loss. It represents the first demonstration of a fully integrated LiDAR transmitter on the multi-layer silicon-nitride-on-silicon photonic platform, revealing the potential of complementary integration in the effort toward a LiDAR transmitter of sufficient optical power budget.

Leaf thermal tolerance and sensitivity of temperate tree species are correlated with leaf physiological and functional drought resistance traits

Climate change is causing more frequent and severe climatic events, such as extreme heat and co-occurring drought, potentially accelerating tree mortality. Which tree species will cope better with those extreme events is still being researched. This study focuses on heat as a physiological stress factor and interspecific variation of thermal tolerance and sensitivity traits in 15 temperate coniferous and broad-leaved tree species. We investigate (1) whether thermal tolerance and sensitivity traits correlate with a drought-related physiological trait, particularly the leaf turgor loss point (πtlp, wilting point), and (2) how thermal tolerance and sensitivity traits co-vary within different tree-functional types classified by morphological and physiological traits of the leaf, i.e., leaf mass per area (LMA) and percentage loss of area (PLA). The study was carried out in the Traunstein Forest Dynamics Plot of the ForestGEO network in Germany. The temperature response of the maximum quantum yield of photosystem II (Fv/Fm) on leaf discs was determined, from which various physiological leaf traits were estimated, one of which is the breaking point temperature (T5), the temperature at which Fv/Fm declines by 5%. Additionally, the temperature of 50% (T50) and 95% (T95) decline in Fv/Fm was evaluated. The decline width between T50 and T5 (DWT50−T5) was taken as an indicator of the species’ thermal sensitivity. The breaking point temperature ranged from 35.4 ± 3.0 to 47.9 ± 3.9 °C among the investigated tree species and T50 ranged between 46.1 ± 0.4 and 53.6 ± 0.7 °C. A large interspecific variation of thermal tolerance and sensitivity was found. European ash (Fraxinus excelsior L.) was the most heat-sensitive species, while Wild cherry (Prunus avium L.) was the least heat-sensitive species. Species with a more negative πtlp tended to have a higher breaking point temperature than species with a less negative πtlp. A lower thermal sensitivity characterized species with a higher LMA, and high PLA was found in species with low thermal sensitivity. Accordingly, species with thicker and tougher leaves have lower thermal sensitivity which coincides with a lower wilting point. We conclude that species that develop drought-adapted foliage can cope better with heat stress. Further, they might be able to maintain transpirational cooling during combined heat and drought stress, which could lessen their mortality risk during climatic extremes.

A localized adaptive comfort model for free-running low-income housing in Mumbai, India

The nexus of thermal comfort, affordability, and resilient buildings is receiving great attention in the rapidly urbanizing world. Understanding the thermal comfort needs, and preferences of the low-income population are crucial in developing an equitable approach to fight climate change and meet sustainable development goals. However, thermal comfort is a contextual construct that requires a localized rather than a universal one-size-fits-all approach. This study proposes a novel AdaptiveComfort forLow-Income Housing (ACL) model for the free-running low-income housing of Mumbai, India through a longitudinal field study method. 6266 observations from low-income housing located within the warm humid region were gathered to examine the thermal comfort conditions of the vulnerable population. Lower thermal sensitivity and a wider comfort temperature band of 25.1 °C to 31.9 °C for occupants were observed as compared to their affluent counterparts. The existing national and international comfort standards proved to be ineffective in predicting comfort conditions for Indian low-income occupants. The localized ACL model developed here is a first-of-its-kind attempt in the Indian context toward improving thermal comfort and built environment sustainability in low-income housing.

Comprehensive physico-chemical and rheo-mechanical characterization of multiple asphalt binder microphases to meet Egyptian conditions

Egypt, nowadays, has obvious complementary advantages in the infrastructure construction sector especially in the fields of highways and airports, resulting in drawing attention to utilizing polymer-modified asphalt (PMA). The main aim of this study is investigating physical, chemical, mechanical, and rheological characteristics of five asphalt binder microphases at different aging conditions to nominate which one best suit the Egyptian climatic conditions through a comprehensive experimental testing matrix. The five examined binder microphases are: base asphalt (BA), recovered asphalt (RA), crumb rubber-modified asphalt (CRMA), CRMA with RA (CRRA), and styrene–butadiene styrene-modified asphalt (SBSMA) which are locally available. First, qualitative, and quantitative analytical tests are used to study the physical and microstructural properties of each microphase component of the tested asphalt binders. Additionally, the mechanical and rheological properties of the investigated asphalt binder microphases at original, short-term aged, and long-term aged conditions are examined at different temperature levels. Overall, the testing results show physico-chemical interactions between the BA and the used polymers during mixing and aging processes. The CR and SBS play a significant role in delaying the decomposition process, improving thermal stability, softening point, and Superpave performance grade as well as enhancing rutting, fatigue, low thermal resistance, aging sensitivity, and temperature susceptibility. Carbonyl, Sulfoxide, and Phase angle aging indices are significantly correlated and are rationally able to characterize the aging behavior of the investigated binder microphases. Finally, CRMA, CRRA, and SBSMA proved their performance suitability among the investigated microphases to match the Egyptian climatic conditions.

A study of subtropical park thermal comfort and its influential factors during summer

Outdoor thermal comfort is significantly relevant to human's quality of life. Thus, it has been frequently studied by investigators. This study explored people's thermal responses to environments and the subjective factors that might affect thermal comforts with respect to two urban parks in Xindu, a satellite city in the Chengdu Plain (CDP). CDP is located at the southwest of China, which has a subtropical climate. The environment from each of the two parks was studied using current micrometeorology and hoped-for landscape changes (tree canopies, artificial canopies, non-canopying plants, and water surfaces); subjective factors included gender, age, body mass index, clothing isolation, and physical activities. It was found that canopies were the most preferred objective cooling elements, while individual thermal perceptions varied subjectively by age. The highest proportion of volunteers voted for tree canopies as their favourite thermal adjusting element. It was observed that those aged above 55 showed low thermal sensitivity. The remaining group's neutral temperatures (indicated by physiologically equivalent temperature, PET) were close, at approximately 25 °C. This study provides significant direction for future urban planning and landscape design.

Temperature Insensitive Delay-Line Fiber Interferometer Operating at Room Temperature

Environmental temperature fluctuations cause phase changes of the light propagating through optical fibers due to their thermal sensitivity. This limits the stability of fiber delay-line interferometers. Here, we present a thermally-insensitive fiber Mach-Zehnder interferometer. It consists of a hollow core fiber (HCF), which has a low thermal sensitivity coefficient, in one branch and a standard single-mode fiber with a thermal sensitivity coefficient about 25 times larger in the other. By setting their associated length ratio to approximately 25:1, the optical phase of the light in both arms changes by the same amount with temperature, making the difference in their optical paths insensitive to temperature and thus producing thermally-insensitive interference. As the thermal sensitivity coefficient of the optical fibers is itself slightly temperature dependent, exactly-zero sensitivity is achieved at a specific temperature only. We show how this zero-sensitivity temperature can be controlled via control of the relative fiber lengths in the two interferometer arms and set it to room temperature. Further, we show that our interferometer is over 100 times less sensitive to temperature than a single-mode fiber-based interferometer over temperature range as large as 25–50 °C. When considering a simple temperature control that keeps the interferometer within ±1 °C, the demonstrated interferometer achieves over 2000 times lower thermal sensitivity than a single-mode fiber-based interferometer and over 100 times lower sensitivity than an HCF-only based interferometer. Finally, we discuss how the thermal sensitivity of such interferometer depends on the light source wavelength.

Thermoresponsive Polymeric Nanolenses Magnify the Thermal Sensitivity of Single Upconverting Nanoparticles.

Lanthanide-based upconverting nanoparticles (UCNPs) are trustworthy workhorses in luminescent nanothermometry. The use of UCNPs-based nanothermometers has enabled the determination of the thermal properties of cell membranes and monitoring of in vivo thermal therapies in real time. However, UCNPs boast low thermal sensitivity and brightness, which, along with the difficulty in controlling individual UCNP remotely, make them less than ideal nanothermometers at the single-particle level. In this work, it is shown how these problems can be elegantly solved using a thermoresponsive polymeric coating. Upon decorating the surface of NaYF4 :Er3+ ,Yb3+ UCNPs with poly(N-isopropylacrylamide) (PNIPAM), a >10-fold enhancement in optical forces is observed, allowing stable trapping and manipulation of a single UCNP in the physiological temperature range (20-45°C). This optical force improvement is accompanied by a significant enhancement of the thermal sensitivity- a maximum value of 8%°C+1 at 32°C induced by the collapse of PNIPAM. Numerical simulations reveal that the enhancement in thermal sensitivity mainly stems from the high-refractive-index polymeric coating that behaves as a nanolens of high numerical aperture. The results in this work demonstrate how UCNP nanothermometers can be further improved by an adequate surface decoration and open a new avenue toward highly sensitive single-particle nanothermometry.

Physiological responses and adjustments of corals to strong seasonal temperature variations (20-28°C).

Temperature is a key driver of metabolic rates. So far, we know little about potential physiological adjustments of subtropical corals to seasonal temperature changes (>8°C) that substantially exceed temperature fluctuation experienced by their counterparts in the tropics. This study investigated the effect of temperature reductions on Montastraea cavernosa and Porites astreoides in Bermuda (32°N; sea surface temperature ∼19-29°C) over 5 weeks, applying the following treatments: (i) constant control temperature at 28°C, and (ii) temperature reduction (0.5°Cday-1) followed by constant temperature (20 days; acclimatization period) at 24°C and (iii) at 20°C. Both species decreased photosynthesis and respiration during temperature reduction as expected, which continued to decrease during the acclimatization period, indicating adjustment to a low energy turnover rather than thermal compensation. Trajectories of physiological adjustments and level of thermal compensation, however, differed between species. Montastraea cavernosa zooxanthellae metrics showed a strong initial response to temperature reduction, followed by a return to close to control values during the acclimatization period, reflecting a high physiological flexibility and low thermal compensation. Porites astreoides zooxanthellae, in contrast, showed no initial response, but an increase in pigment concentration per zooxanthellae and similar photosynthesis rates at 24°C and 20°C at the end of the experiment, indicating low acute thermal sensitivity and the ability for thermal compensation at the lowest temperature. Respiration decreased more strongly than photosynthesis, leading to significant build-up of biomass in both species (energy reserves). Results are important in the light of potential poleward migration of corals and of potential latitudinal and species-specific differences in coral thermal tolerance.

Air flowing induced thermo-optic effect for thermal sensitivity reduction in anti-resonant hollow core fibers

The signal propagation delay through an optical fiber changes with environmental temperature, imposing a fundamental limit on performances in many fiber-optic applications. It has been shown that the thermal coefficient of delay (TCD) in hollow core fibers (HCFs) can be 20 times lower than in standard single-mode fibers (SSMFs). To further reduce TCD over a broad wavelength range at room temperature, so that to enrich fiber-optic applications in time- synchronization scenarios, the thermal expansion effect of silica glass must be compensated for. Exploiting the thermo-optic effect of air inside an anti-resonant hollow core fiber (ARF) can be a feasible solution. Nevertheless, an accurate description of the air flow in the course of temperature variation is highly needed to predict the influence of this effect. This work develops an analytical model for quantitatively calculating this temperature-induced air-flowing effect. Across a range of parameters of core diameter, fiber length, and temperature change rate, the experimentally measured propagation delay changes agree well with our model. The resultant low thermal sensitivity is also validated in non-steady conditions and in a practically usable SSMF-ARF-SSMF chain. Our model indicates that a >40-fold TCD reduction relative to SSMFs can be realized in a 60-m-long, 50-µm-diameter ARF, and further TCD reduction should be possible by properly engineering the gas type and the ambient pressure.

Hollow-core fiber Fabry-Perot interferometers with reduced sensitivity to temperature.

We demonstrate a 3× thermal phase sensitivity reduction for a hollow-core fiber (HCF) Fabry-Perot interferometer by winding the already low temperature sensitivity HCF on to a spool made from an ultralow thermal expansion material. A record low room temperature fiber coil phase thermal sensitivity of 0.13 ppm/K is demonstrated. The result is of particular interest in reducing the thermal sensitivity of HCF-based Fabry-Perot interferometers (for which existing thermal sensitivity reduction methods are not applicable). Our theoretical analysis predicts that significantly lower (or even zero) thermal sensitivity should be achievable when a spool with a slightly negative coefficient of thermal expansion is used. We also suggest a method to fine-tune the thermal sensitivity and analyze it with simulations.

Broadband Silicon Nitride Power Splitter Based on Bent Directional Couplers with Low Thermal Sensitivity.

Directional couplers, as power splitters, have provided a significant contribution for light splitting and combining in silicon photonics. However, the splitting ratio of conventional directional couplers is very sensitive to wavelength, which limits the bandwidth and the transmission performance of the devices. In this work, a silicon nitride bent directional coupler with large bandwidth, large fabrication tolerance, and low thermal sensitivity is proposed and demonstrated through simulation analysis and experiments. Moreover, the fabrication process of 400 nm thick silicon nitride photonic devices is described, which are compatible with complementary metal–oxide–semiconductor technology. The 1 dB bandwidth of the bent waveguide coupler can reach 80 nm, and the thermal sensitivity is reduced by 85% compared to the silicon-based devices.

Temperature Extremes and Sex-Related Physiology, Not Environmental Variability, Are Key in Explaining Thermal Sensitivity of Bimodal-Breathing Intertidal Crabs

Global temperature increases are predicted to have pronounced negative effects on the metabolic performance of both terrestrial and aquatic organisms. These metabolic effects may be even more pronounced in intertidal organisms that are subject to multiple, abruptly changing abiotic stressors in the land-sea transition zone. Of the available studies targeting the intertidal environment, emphasis has largely been on water-breathing model organisms and this selective focus resulted in limited reliable forecasts on the impact of global warming on primarily air-breathing intertidal species. We investigated the thermal sensitivity of six phylogenetically related fiddler crab species that occupy different microhabitats on intertidal shores from south America and east Asia to test how bimodal-breathing intertidal ectotherms cope with thermal stress. We examined the metabolic physiology and thermal limits of the crabs by measuring their cardiac function and oxygen consumption along a thermal gradient. Their specific thermal microhabitat was also appraised. We found that subtropical fiddler crab species inhabiting vegetated microhabitats have lower upper lethal temperatures and therefore greater thermal sensitivity in comparison to their tropical counterparts. Additionally, females exhibited higher oxygen consumption and lower lethal temperatures in comparison to males. Our results contradict previous predictions that species from higher latitudes that experience greater temperature variability have broader latitudinal distributions, greater phenotypic plasticity and lower thermal sensitivity. Furthermore, the higher thermal sensitivity demonstrated by female fiddler crabs with respect to males strongly suggests a role of both gametogenesis and physiological dimorphism on the thermal performance of tropical and subtropical intertidal organisms. These observations ultimately, advocates for further studies on sex-biased and development-biased thermal sensitivity before drawing any generalizations based on a single sex or life stage.

Performance evaluation of personal thermal comfort models for older people based on skin temperature, health perception, behavioural and environmental variables

Personal thermal comfort models hold the promise of a more accurate way to predict thermal comfort and therefore a more reliable approach for managing indoor thermal environments. They can be especially relevant as an assistive tool for people with lower thermal sensitivity or with limitations to thermal management and adaptation, such as older people. Nonetheless, although in constant development, studies on personal comfort models continue to focus on office environments and younger adults. This paper explores the development of personal comfort models to predict older people's thermal needs in their homes and evaluates the models' predictive performances in comparison with conventional generalised approaches. Machine learning and environmental, behavioural, health and skin temperature measurements were used to develop individual models for a set of older adults in South Australia. The results show that, on average, the personal thermal comfort models using all studied inputs, except for health perception, presented an optimal accuracy of 66.72%, a Cohen's Kappa of 50.08% and AUC of 0.77, a superior performance when compared with generalised approaches. Results have also highlighted the need for further research on combining physiological sensing, individualised predictive modelling and wearable comfort systems, as well as on defining thermal preference misclassification costs in the context of older people.