Last glacial maximum summer temperature gradients from terrestrial gastropod assemblages in Peoria Silt (loess), Midcontinent USA

Too close for comfort? Mesozooplankton dynamics in Marine Protected Areas adjacent to mining tailings on the southeastern Brazilian shelf.

• Variable porosity open receivers can reduce maximum receiver temperature. • Selection of the porosity distribution within the receiver can increase the receiver efficiency. • Variable porosity changes flow velocity through porous receiver sections. Hotspots caused by asymmetric solar flux distributions present a critical design challenge in cavity receivers used for concentrated solar power (CSP) systems. These thermal nonuniformities induce steep temperature gradients that compromise the thermo-mechanical integrity and operational lifetime of receivers. This study proposes and evaluates a variable porosity design methodology for porous volumetric absorbers as a passive means to mitigate the effects of nonuniform solar irradiance. Using Monte Carlo Ray Tracing (MCRT), heat flux distributions for a spherical cavity receiver were computed based on site-specific heliostat field data from a Lancaster, CA test facility. These flux maps served as inputs for a coupled finite element model (FEM) incorporating radiative transfer (via the P1 approximation), local thermal non-equilibrium (LTNE) energy balances, and flow through porous media governed by Brinkman-Forchheimer extended Darcy’s law. The receiver was discretized into angular sectors, and six porosity distribution functions, including linear, quadratic, and piecewise variants, were applied to redistribute airflow and minimize solid matrix temperature gradients. Results show that the piecewise upward distribution, which channels more flow to high-flux regions, significantly improves receiver thermal efficiency and reduces peak solid temperatures under both summer and winter operating conditions. Performance metrics such as outlet air temperature, maximum solid-phase temperature, and average fluid velocity were used to evaluate each configuration. The proposed variable porosity framework demonstrates that tailored spatial control of internal flow can mitigate hotspot effects, enhance thermal performance, and support the economic viability of high-flux solar receivers. Future work will focus on optimization of the porosity distribution function and integration with structural stress modeling to quantify reliability improvements.

Influence of the burial depth of series-connected shallow vertical U-tube ground heat exchangers on rock mass temperature

From invisible to quantifiable: unmasking non-extractable HT2/T2 glycosides.

This study presents results of an effort to validate the numerical implementation of the thermo-hydro-mechanical model with thermo-osmosis in the finite-element simulator OpenGeoSys. The simulator’s capability to capture thermo-osmotic effects on pressure fields under thermal gradients is evaluated by comparison with a reference analytical solution and field data from the Mont Terri Deep Borehole experiment. The results demonstrate that the thermo-osmosis significantly influences subsurface pressure dynamics, and OpenGeoSys effectively reproduces this phenomenon. Additionally, an improved formulation of the THM process is outlined, and a model of the experiment is extended by inhomogeneous effects to reproduce the observed data better. This work illustrates how combining analytical verification, numerical modeling and field observations can improve the interpretation of complex THM processes in clay formations. • Validation of simulation software for thermo-osmosis based on borehole data. • Discussion of sources of uncertainty in thermo-osmosis models. • Tests of different hypotheses on physical phenomena to improve fit to data. • Variable geothermal gradients and permeability heterogeneity act synergistically. • Heterogeneity is important and has to be considered appropriately in the models.

Plugging criteria based on stress analysis for high-pressure feedwater heater tubes with external circumferential wall-thinning flaws

Comparative study of spark plasma sintering and microwave synthesis for high-entropy oxides: Lu-Yb-Tm-Er-Ho-O system

Amphibians, like other ectotherms, must balance conflicting demands for energy expenditure, physiological processes, and behaviour in response to environmental temperature variations that influence their survival and reproduction. Understanding these dynamics is crucial for assessing amphibians' resilience to climate change and identifying the stressors they face in their thermal environments. Our study investigated the influence of ambient temperature (Ta) on resting metabolic rate (RMR) in adult Rana temporaria and how the frogs' thermoregulatory reality in the field (field body temperature, Tb) while being active aligns with their responses to a wider range of temperatures in a thermal gradient (preferred temperature, Tpref). As anticipated for ectotherms, the RMR increased with Ta, doubling with each 10°C increment, in accordance with the Q10 coefficient. Consequently, absolute changes in RMR increased with increasing temperature. In the thermal gradient experiment, frogs primarily selected temperatures around 25°C. At this temperature, which is not too far from the critical maximum temperature (CTmax) of 30°C, RMR was 0.106mL O2 g-1h-1. The mismatch between actual field Tb and laboratory Tpref highlights the constraining influence of other environmental factors such as favourable microhabitat availability or hygric conditions. This study suggests an effective balance between energy requirements and thermoregulatory behaviour in R. temporaria, if favourable conditions are available. However, it also shows that the environmental reality of animals often deviates from unimpeded preferences of active individuals and thus results from experimental procedures might not necessarily reflect the situation in the field.

Zeotropic refrigerant mixtures are promising alternatives to high–global warming potential fluids due to their thermodynamic flexibility and temperature glide, which enables improved thermal matching in heat exchangers. However, the non-isothermal phase change and associated mass transfer effects introduce strong non-equilibrium behavior that challenges accurate prediction of flow boiling heat transfer. In this study, a generalized non-equilibrium heat transfer model is developed for annular flow boiling of binary zeotropic mixtures based on film theory. The model explicitly resolves coupled heat and mass transfer across the liquid film, vapor–liquid interface, and vapor core, accounting for interfacial temperature variation, axial and radial mass diffusion resistance, and species segregation. An iterative solution strategy is employed to simultaneously determine the interfacial temperature and heat flux by enforcing energy balance across all phases. A key advantage of the proposed framework is its flexibility, allowing integration of multiple liquid-film flow boiling correlations to optimize predictive performance for different mixtures and operating conditions. The model is validated against 1139 experimental data points covering 28 binary refrigerant pairs, a wide range of operating conditions, and temperature glides up to 35.8 °C, and it has achieved 81% of predictions within ±30% deviation. Overall, the proposed non-equilibrium framework consistently outperforms eleven existing flow boiling correlations, demonstrating improved robustness and broad applicability for modeling evaporation in zeotropic mixtures and supporting the design of advanced refrigeration and heat pump systems. • A generalized non-equilibrium model is developed for binary zeotropic evaporation. • Interfacial temperature and concentration gradients are included. • Validated against 1139 data points from various refrigerant pairs. • Allows tailored predictions for specific refrigerant mixtures. • Outperforms eleven existing correlations with 81% accuracy within ±30%.

Polycyclic aromatic hydrocarbons (PAHs) are organic pollutants widely abundant in multi-stressed coastal environments worldwide. Herein, seawater (dissolved phase/suspended particles) and sediment samples were collected during a survey on June 2024 across five stations, reflecting multiple anthropogenic stressors, at the heavily impacted Saronikos Gulf, Greece. In the collected samples, 47 PAH homologues were monitored by gas chromatography - mass spectrometry, resolved into source-related profiles by employing the EPA's Positive Matrix Factorization model and examined in relation to bacterial community composition inferred from eDNA metabarcoding sequencing. Our aim was to assess the potential links of PAH sources to microbial diversity and community structure, providing a targeted tool to support coastal monitoring of complex PAHs mixtures in multi-stressed environments. Total PAHs (TPAH₄₇) concentrations ranged between 127 and 462ngL-1 in the dissolved phase with alkylated 2- and 3-ring compounds dominating, 5.78-10.4ngL-1 in suspended particles and 860-5450ngg-1 in sediments, dominated by high-MW 4- to 7-ring compounds. Bacterial community composition based on 16S rRNA gene metabarcoding differed between seawater and sediments. In seawater, community co-varied with physicochemical gradients (temperature, salinity, dissolved oxygen, chlorophyll-a), while PAH source profiles showed weaker associations. In sediments, bacterial assemblages exhibited a stronger statistical association with source-resolved PAH profiles based on the constrained ordination framework. In the dissolved phase the taxa Flavobacterium, Sulfitobacter, and Labedella gwakjiensis, in the suspended particles the genus Algiphilus, and in sediments the species Parahaliea maris were identified as source-associated candidate indicator taxa, highlighting compartment-specific potential bioindicators that require functional validation with -omics tools.

Silica crystal grain growth in a soda-lime-silicate melt subject to a temperature gradient

Co-optimization of area ratio and material fraction in segmented N-type thermoelectric legs using XGBoost–ANN surrogates

A lubricant film separates metal-to-metal contacts and is critical for industrial components such as bearings, engines, and transmissions, to assure their durability and energy efficiency. The lubricant film thickness can reflect oil rheological properties and thus its degradation, while the interfacial temperature variation is mainly caused by friction heating that can reflect wear conditions. Therefore, simultaneous monitoring of these two key variables will enable comprehensive characterization of the lubrication condition, facilitating predictive maintenance of energy equipment. Traditional ultrasonic measurement techniques based on longitudinal waves have been widely employed for monitoring lubricant film thickness; however, the acoustic velocity in such methods is highly sensitive to temperature and lacks effective compensation mechanisms. This severely limits their applicability in high-precision scenarios. To address this issue, this paper proposes a hybrid ultrasonic measurement approach that employs co-located longitudinal and shear waves. Shear waves propagate only in solids and are unaffected by the lubricant film, while longitudinal waves travel through both solids and liquids. Thus, the method utilizes the longitudinal wave to estimate film thickness and the shear wave to evaluate solid temperature and infer interfacial temperature. This temperature information is then used to improve estimates of the phase of the wave that is propagating in the solid medium and the assumed acoustic velocity in the lubricating film, thereby enhancing the accuracy and robustness of thickness measurements. Experimental validation was conducted on both a heating plate and a rheometer system. The temperature experiments demonstrated the feasibility of using ultrasound to measure temperature gradients within solids. On the rheometer platform, practical lubrication conditions were simulated by adjusting the upper plate temperature, allowing for further evaluation of the shear-wave-based temperature sensing method. Experimental results confirm that the proposed method can accurately obtain interfacial temperatures and compensate for temperature-induced errors in the lubricant film thickness measurements.

Effect of temperature gradients in large-format pouch-type NMC/graphite lithium-ion battery on degradation

Effects of cooling step and static magnetic field on the freezing characteristics of apple.

Evaluation of fluid behavior and turnover in aquaculture tanks using CFD and transient temperature fields

Finite element modeling of particle-scale heating of reclaimed asphalt pavement (RAP) in drum plants considering size, material, and internal temperature gradients

Sodium alginate-based biomimetic crack-network Janus foam evaporator toward robust solar desalination, wastewater purification, and thermoelectric power generation.

A spiral aerogel-fabric composite evaporator for all-weather freshwater generation via solar tracking and synergistic hydrothermal management.