Comparative analysis of thermoregulation models to assess heat strain in moderate to extreme heat.

As global temperatures rise due to climate change, the frequency and intensity of heatwaves are increasing, posing significant threats to human health, productivity, and well-being. Thermoregulation models are important tools for quantifying the risk of extreme heat, providing insights into physiological strain indicators such as core and skin temperatures, sweat rates, and thermal comfort levels. This study evaluated four thermoregulation models of varying complexity, differentiated by the geometry and underlying thermoregulatory mechanisms.

Photoredox-Catalyzed Decarboxylation of Oxetane-2-Carboxylic Acids and Unique Mechanistic Insights.

Oxetanes are valuable motifs in medicinal chemistry applications, with demonstrated potential to serve as bioisosteres for an array of functional groups. Through the visible-light-mediated photoredox hydrodecarboxylation of 2-aryl oxetane 2-carboxylic acids this work enables access to the products of a [2+2]-photocycloaddition between alkenes and aryl aldehydes without the challenges associated with a traditional UV-light-mediated Paternò-Büchi reaction. Investigation into the hydrodecarboxylation mechanism reveals substrate-dependent modes of initiation under the conditions reported herein.

Impact of rheology on formation of oil-in-liquid metal emulsions.

To quantify how the viscosities of silicone oil (SO) and liquid metal (LM) relate to emulsion-formation (LM-in-SO SO-in-LM), a process was developed to produce LM pastes with adjustable viscosity and minimal oxide and bubbles. Increased LM viscosity allows greater silicone oil intake and/or intake of higher-viscosity silicone oils.

First Exploration of Monopole-Driven Shell Evolution above the N=126 Shell Closure: New Millisecond Isomers in ^{213}Tl and ^{215}Tl.

Isomer spectroscopy of heavy neutron-rich nuclei beyond the N=126 closed shell has been performed for the first time at the Radioactive Isotope Beam Factory of the RIKEN Nishina Center. New millisecond isomers have been identified at low excitation energies, 985.3(19) keV in ^{213}Tl and 874(5) keV in ^{215}Tl.

Impact of tent shade on heat exposures and simulated heat strain for people experiencing homelessness.

Concurrent increases in homelessness and heat intensity, duration, and frequency translate to an urban heat risk trap for the unsheltered population. Homelessness is both a driver and consequence of poor health, co-creating distinct geographies with various risk factors that exacerbate heat vulnerability. We tested the efficacy of different tent shadings over identical tents often observed in the Phoenix area (white bedsheet, mylar, tarp, and aluminum foil) and compared them to a control tent (uncovered) and ambient conditions.

Simultaneous imaging of multi-pore sweat dynamics and evaporation rate measurement using wind tunnel ventilated capsule with infrared window.

Sweat evaporation is critical to human thermoregulation, but current understanding of the process on 20 μm to 2 cm scale is limited. To this end, we introduce a wind-tunnel-shaped ventilated capsule with an infrared window for simultaneous infrared sweat imaging and evaporation rate measurement. Implementing the capsule in pilot human subject tests suggests that the common assumption of sweat being an isothermal film is only valid when the evaporation rate is low and sweat forms puddles on the skin.

Particle-assisted formation of oil-in-liquid metal emulsions.

Gallium-based liquid metals (LMs) have surface tension an order of magnitude higher than water and break up into micro-droplets when mixed with other liquids. In contrast, silicone oil readily mixes into LM foams to create oil-in-LM emulsions with oil inclusions. Previously, the LM was foamed through rapid mixing in air for an extended duration (over 2 h).

Proton Shell Gaps in N=28 Nuclei from the First Complete Spectroscopy Study with FRIB Decay Station Initiator.

The first complete measurement of the β-decay strength distribution of _{17}^{45}Cl_{28} was performed at the Facility for Rare Isotope Beams (FRIB) with the FRIB Decay Station Initiator during the second FRIB experiment. The measurement involved the detection of neutrons and γ rays in two focal planes of the FRIB Decay Station Initiator in a single experiment for the first time. This enabled an analytical consistency in extracting the β-decay strength distribution over the large range of excitation energies, including neutron unbound states.

Characterization of human extreme heat exposure using an outdoor thermal manikin.

Extreme heat is a current and growing global health concern. Current heat exposure models include meteorological and human factors that dictate heat stress, comfort, and risk of illness. However, radiation models simplify the human body to a cylinder, while convection ones provide conflicting predictions.

A simple three-cylinder radiometer and low-speed anemometer to characterize human extreme heat exposure.

As populations and temperatures of urban areas swell, more people face extreme heat and are at increasing risk of adverse health outcomes. Radiation accounts for much of human heat exposure but is rarely used as heat metric due to a lack of cost-effective and accurate sensors. To this end, we fuse the concepts of a three-globe radiometer-anemometer with a cylindrical human body shape representation, which is more realistic than a spherical representation.

Printable Liquid Metal Foams That Grow When Watered.

Pastes and "foams" containing liquid metal (LM) as the continuous phase (liquid metal foams, LMFs) exhibit metallic properties while displaying paste or putty-like rheological behavior. These properties enable LMFs to be patterned into soft and stretchable electrical and thermal conductors through processes conducted at room temperature, such as printing. The simplest LMFs, featured in this work, are made by stirring LM in air, thereby entraining oxide-lined air "pockets" into the LM.

Thermal modulation of skin friction at the finger pad.

Preliminary human studies show that reduced skin temperature minimises the risk of mechanically induced skin damage. However, the mechanisms by which cooling enhances skin tolerance to pressure and shear remain poorly understood. We hypothesized that skin cooling below thermo-neutral conditions will decrease kinetic friction at the skin-material interface.

Rare ^{40}K Decay with Implications for Fundamental Physics and Geochronology.

Potassium-40 is a widespread, naturally occurring isotope whose radioactivity impacts subatomic rare-event searches, nuclear structure theory, and estimated geological ages. A predicted electron-capture decay directly to the ground state of argon-40 has never been observed. The KDK (potassium decay) collaboration reports strong evidence of this rare decay mode.

Thermophysiological aspects of wearable robotics: Challenges and opportunities.

Technological advancements in the last two decades have enabled development of a variety of mechanically supporting wearable robots (i.e. exoskeletons) that are transitioning to practice in medical and industrial settings.

Microsecond Isomer at the N=20 Island of Shape Inversion Observed at FRIB.

Excited-state spectroscopy from the first experiment at the Facility for Rare Isotope Beams (FRIB) is reported. A 24(2)-μs isomer was observed with the FRIB Decay Station initiator (FDSi) through a cascade of 224- and 401-keV γ rays in coincidence with ^{32}Na nuclei. This is the only known microsecond isomer (1  μs≤T_{1/2}<1  ms) in the region.

Impact of human body shape on forced convection heat transfer.

Predicting human thermal comfort and safety requires quantitative knowledge of the convective heat transfer between the body and its surrounding. So far, convective heat transfer coefficient correlations have been based only upon measurements or simulations of the average body shape of an adult. To address this knowledge gap, here we quantify the impact of adult human body shape on forced convection.

Crossing N=28 Toward the Neutron Drip Line: First Measurement of Half-Lives at FRIB.

New half-lives for exotic isotopes approaching the neutron drip-line in the vicinity of N∼28 for Z=12-15 were measured at the Facility for Rare Isotope Beams (FRIB) with the FRIB decay station initiator. The first experimental results are compared to the latest quasiparticle random phase approximation and shell-model calculations. Overall, the measured half-lives are consistent with the available theoretical descriptions and suggest a well-developed region of deformation below ^{48}Ca in the N=28 isotones.

β-Delayed One and Two Neutron Emission Probabilities Southeast of ^{132}Sn and the Odd-Even Systematics in r-Process Nuclide Abundances.

The β-delayed one- and two-neutron emission probabilities (P_{1n} and P_{2n}) of 20 neutron-rich nuclei with N≥82 have been measured at the RIBF facility of the RIKEN Nishina Center. P_{1n} of ^{130,131}Ag, ^{133,134}Cd, ^{135,136}In, and ^{138,139}Sn were determined for the first time, and stringent upper limits were placed on P_{2n} for nearly all cases. β-delayed two-neutron emission (β2n) was unambiguously identified in ^{133}Cd and ^{135,136}In, and their P_{2n} were measured.

Mechanism of Oil-in-Liquid Metal Emulsion Formation.

Gallium-based liquid metals (LMs) combine metallic properties with the deformability of a liquid, which makes them promising candidates for a variety of applications. To broaden the range of physical and chemical properties, a variety of solid additives have been incorporated into the LMs in the literature. In contrast, only a handful of secondary fluids have been incorporated into LMs to create foams (gas-in-LM) or emulsions (liquid-in-LM).

Photochemical Strategies Enable the Synthesis of Tunable Azetidine-Based Energetic Materials.

Despite their favorable properties, azetidines are often overlooked as lead compounds across multiple industries. This is often attributed to the challenging synthesis of densely functionalized azetidines in an efficient manner. In this work, we report the scalable synthesis and characterization of seven azetidines with varying regio- and stereochemistry and their application as novel azetidine-based energetic materials, enabled by the visible-light-mediated Paternò-Büchi reaction.

Human body radiation area factors for diverse adult population.

Radiation accounts for a significant fraction of the human body and environment heat exchange and strongly impacts thermal comfort and safety. The direct radiative exchange between an individual and a source or sink can be quantified using the effective (f) and projected radiation area factors (f). However, these factors have not been quantified for half of the population of the USA with an above-average body mass index (BMI).

Analysis of thermocouple-based finger contact temperature measurements.

The understanding of heat conduction during finger contact with cooler or hotter objects is important for designing many electronic devices and for setting safety standards in a variety of occupational settings. In the most common experimental approach to study this process, a micro-thermocouple is placed at the finger-object interface. However, the interpretation of what this measurement corresponds to is not clear.

Enhancing Thermal Transport in Silicone Composites via Bridging Liquid Metal Fillers with Reactive Metal Co-Fillers and Matrix Viscosity Tuning.

Polymer matrix composites containing room temperature liquid metal (LM) microdroplets offer a unique set of thermo-mechanical characteristics that makes them attractive candidates for high performance thermal interface materials. However, to achieve the desired level of the composite thermal conductivity, effective bridging of such fillers into interconnected percolation networks needs to be induced. Thermal percolation of the LM microdroplets requires two physical barriers to be overcome.

Gallium oxide-stabilized oil in liquid metal emulsions.

Gallium based liquid metals (LM) have prospective biomedical, stretchable electronics, soft robotics, and energy storage applications, and are being widely adopted as thermal interface materials. The danger of gallium corroding most metals used in microelectronics requires the cumbersome addition of "barrier" layers or LM break-up into droplets within an inert matrix such as silicone oil. Such LM-in-oil emulsions are stabilized by native oxide on the droplets but have decreased thermal performance.