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Radiative 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. [ABSTRACT FROM AUTHOR]

• Room-temperature magnetocaloric refrigeration prototype with helium as the heat transfer fluid and packed particle Gd 0.8875 Ce 0.1025 Si 0.84 Cr 0.19 as the refrigerant. • Measurements on temperature spans and cooling power with three particle sizes at two different operating cycles. • Reduction of performance in large particles from insufficient thermal diffusion in faster cycle. • Validated numerical model and compared effects of viscous dissipation and thermal diffusion. • Implications of magnetocaloric refrigerant with low thermal diffusivity for cryogenic temperatures discussed. Magnetocaloric refrigeration has strong potential towards achieving high efficiency hydrogen liquefaction. Optimising parameters such as particle size and operating cycles can have a significant impact on liquefaction performance. This work reports on a room temperature magnetocaloric refrigeration prototype designed with helium as the heat transfer fluid and packed particle Gd 0.8875 Ce 0.1025 Si 0.84 Cr 0.19 as the refrigerant. The temperature spans and cooling power with three different particle sizes at two different operating cycles were measured. A maximum temperature span of 16.7 K and a maximum cooling power of 8.6 W kg−1 were obtained. Reduction of performance in the faster cycle was observed in larger particles due to insufficient thermal diffusion time and its implications for cryogenic temperatures are discussed. A numerical model was developed based on the experimentally observed variation of the temperature span and cooling power with particle size and cycle duration. This model was then used to study the competing effects of viscous dissipation and thermal diffusion for different particle sizes and cycle durations. [ABSTRACT FROM AUTHOR]

• A coupled conduction-radiation model to analyze high-temperature LFA data. • Accurate thermal conductivity of glass is obtained up to 1000 °C. • Develop a simple modified transparent model without optical properties. • Applicability of the modified transparent model is established. Laser flash analysis (LFA) is a widely used technique in the scientific and industrial communities for measuring the thermal diffusivity and conductivity of materials. However, traditional fitting methods based solely on heat conduction do not account for radiation heat transfer in transparent and semi-transparent materials, which becomes significant at high temperatures. In this study, we have developed a coupled radiation-conduction model that considers the optical properties of materials to accurately extract thermal diffusivity from LFA measurements. We conducted LFA measurements on fused silica glass samples of varying thicknesses and within the temperature range of 25 to 1000 °C and fitted the data with the model. Since the coupled model requires optical properties as input parameters, which are often unavailable for new materials, we have also proposed a modified transparent model. Compared to the coupled model, results from the modified transparent model generally overestimate thermal conductivity, but the errors are acceptable in silica glass with small thickness. We also investigated the applicability of the modified transparent model with materials of different optical properties. [ABSTRACT FROM AUTHOR]

• Non-contact technique to handle high-temperature corrosive liquids. • Frequency controlled thermal penetration depth eliminates natural convection. • Front-side sensing and vertical holder orientation minimize salt creeping effect. • Accurate thermal conductivity data obtained for nitrate and chloride salts. • MPR is applicable for in-situ diagnostics of high-temperature thermal system. Molten salts are being used or explored for thermal energy storage and conversion systems in concentrating solar power and nuclear power plants. Thermal conductivity of molten salts is an important thermophysical property dictating the performance and cost of these systems, but its accurate measurement has been challenging, as evidenced by wide scattering of existing data in literature. The corrosive and conducting nature of these fluids also leads to time consuming sample preparation processes of many contact-based measurements. Here, we report the measurement of thermal conductivity of molten salts using a modulated photothermal radiometry (MPR) technique, which is a laser-based, non-contact, frequency-domain method adopted for molten salts for the first time. By unitizing the advantages of front side sensing of frequency-domain measurements and the vertical holder orientation, the technique can minimize the natural convection and salt creeping effects, thus yielding accurate molten salt thermal conductivity. The MPR technique is first calibrated using standard molten materials including paraffin wax and sulfur. It is then applied on measuring pure nitrate salts (NaNO 3 and KNO 3), solar salt (NaNO 3 –KNO 3 mixture), and chloride salt (NaCl–KCl–MgCl 2). The measurement results are compared with data from literature, especially those obtained from laser flash analysis (LFA). Our results demonstrate that the MPR is a convenient and reliable technique of measuring thermal conductivity of molten salts. Accurate thermal conductivity data of molten salts will be valuable in developing the next-generation high-temperature thermal energy storage and conversion systems. [ABSTRACT FROM AUTHOR]

• Modeled hydrogen liquefication from 80 to 20 K in a multi-stage AMR system using permanent magnets with 1-Tesla field. • Achieved over 60% of Carnot COP with the multistage design with optimized operation conditions. • Compared two types of 1D AMR models: steady state and time-dependent models. Hydrogen (H 2) is promising alternative to replace fossil fuels, but its transport and storage has been challenging. As H 2 fuel cell vehicles are gaining traction, the infrastructure for storing large amounts of liquid H 2 is needed. However, liquid H 2 would suffer from boil-off loss, and traditional vapor compression refrigeration systems would not be able to economically recover the lost H 2 due to the low efficiencies at cryogenic temperature. Magnetocaloric (MC) refrigeration systems could possess much higher coefficient of performance (COP) at cryogenic temperature compared to the vapor compression ones. Previous work on cryogenic MC systems, however, have only focused on large scale applications which use superconducting magnets to provide a large magnetic field but are prohibitively expensive to operate for small scale applications, such as that of a H 2 refilling station. In this work, we model the performance of a MC refrigeration cycle using 1-Tesla permanent magnets for H 2 liquefaction, with the objective of cooling H 2 from 80 K (using liquid nitrogen as the heat sink) to 20 K (boiling point of hydrogen). We evaluate main performance metrics including the total work input to the refrigeration system, COP, total MCM mass in the system, and total volume of the permanent magnets, etc. Our modeling results indicate that such a permanent magnet-based MC cooling system is feasible for small-scale H 2 liquefaction, with projected COP values significantly higher than those of vapor compression systems. This work provides design guidelines for future experimental efforts on permanent magnet MC cooling systems for cryogenic cooling. [ABSTRACT FROM AUTHOR]

The use of light to control the course of a chemical/biochemical reaction is an attractive idea because of its ease of administration with high precision and fine spatial resolution. Staudinger ligation is one of the commonly adopted conjugation processes that involve a spontaneous reaction between azides and arylphosphines to form iminophosphoranes, which further hydrolyze to give stable amides. We designed an anthracenylmethyl diphenylphosphinothioester ( 1) that showed promising Staudinger ligation reactivity upon photo-excitation. Broadband photolysis at 360-400 nm in aqueous organic solvents induced heterolytic cleavage of its anthracenylmethyl-phosphorus bond, releasing a diphenylphosphinothioester ( 2) as an efficient traceless Staudinger-Bertozzi ligation reagent. The quantum yield of such a photo-induced heterolytic bond-cleavage at the optimal wavelength of photolysis (376 nm) at room temperature is ≥0.07. This work demonstrated the feasibility of photocaging arylphosphines to realize the photo-triggering of the Staudinger ligation reaction. [ABSTRACT FROM AUTHOR]

PLGA porous microspheres loaded with doxorubicin (DOX) and paclitaxel (PTX) were developed for in situ treatment of metastatic lung cancer. The synergistic effect of the combined drugs was investigated against B16F10 cells to obtain the optimal prescription for in vivo studies. The combination therapy showed great synergism when DOX was the majority in the combination therapy, while they showed moderate antagonism when PTX is in major. The combination of DOX and PTX at a molar ratio of 5/1 showed the best synergistic therapeutic effect in the free form. However, the drugs exhibited more synergism in the PLGA microspheres at a molar ratio of 2/1, due to the difference in drug release rate. The in vivo study verified the synergism of DOX and PTX at the optimal molar ratio. These results suggested that dual encapsulation of DOX and PTX in porous PLGA microspheres would be a promising technology for long effective lung cancer treatment. [ABSTRACT FROM AUTHOR]

Increasingly stringent regulations regarding vehicle emissions have contributed to the diversification of vehicle technologies, resulting in the increasing complexity of typical vehicles that make up a fleet. In order to investigate the real gas emissions of different typical vehicles, tests were conducted using a portable emission measurement system (PEMS) in Beijing and emission studies were conducted on eight light-duty passenger vehicles (LDPVs, including light-duty gasoline passenger vehicles and hybrid electric vehicles), eight heavy-duty passenger vehicles (HDPVs), and four light-duty trucks (LDTs). The results show that the emissions of relevant pollutants from LDPV meet the emission standard limits. The emission factors of CO2, CO, NOX, and HC of China IV and China V hybrid electric vehicles (HEVs) are much smaller than the emission standard limits and the emission factors of other vehicles, which have better emission reduction effects. Among LDPV, heavy-duty passenger vehicles (HDPVs), and LDT, the emissions of HDPV and LDT are extremely high. Emission characteristics vary on different types of roads, with the highest emission factors generally occurring on secondary roads. The micro-trip method was used to explore the influence of speed on emission factors. HEV are less sensitive to speed changes and can still maintain a low emission level at low speeds. The average speed and emission factors of HDPV in micro-trip has a strong correlation. [ABSTRACT FROM AUTHOR]

Here, we present a composite polymer electrolyte incorporated with mesoporous zeolite SBA-15 fillers with improved Li transport and interfacial properties. By regulating Li transport through finely dispersed fillers and improving their interaction with the polyethylene oxide matrix, the symmetrical cell with Li metal exhibits a long cycle time of 730 h, and the Li/5% SBA-15 CPE/LFP delivers a specific capacity of 126 mA h g−1 and capacity retention of 86% after 110 cycles. [ABSTRACT FROM AUTHOR]

Probing short‐lived reaction species is challenging owing to the need for both high signal‐to‐noise ratio, which can require long measurement time, and fast time resolution. Here, a novel in situ sample environment is presented that decouples time resolution from measurement time by distributing reaction time over space for the reaction under flow. In the mixing‐flow reactor, precursor solutions are mixed at a specific position along the flow path, where the reaction is initiated. As the reaction mixture flows within a reaction capillary, the reaction time increases with distance from the mixing point. A measurement can be taken at a specific distance from the mixing point for as long as is needed to accumulate good statistics without compromising the time resolution of the measurement. Applications of the mixing‐flow reactor for pair distribution function measurements of the initial nuclei formed during the hydrolysis of Al3+ at high pH are shown. [ABSTRACT FROM AUTHOR]

Particle beds are widely used in various systems and processes, such as particle heat exchangers, granular flow reactors, and additive manufacturing. Accurate modeling of the thermal conductivity of particle beds and understanding of their heat transfer mechanisms are important. However, previous models were based on simple cubic packing of particles, which could not accurately represent the actual heat transfer processes under certain conditions. Here, we examine the effect of the packing structure on the thermal conductivity of particle beds. We use monodispersed silica microspheres with average particle sizes ranging from 23 to 330 μm as a model material. We employ a transient hot-wire technique to measure the thermal conductivity of the particle beds with packing density of 43%–57% within a temperature range of room temperature to 500 °C and under N2 gaseous pressures of 20–760 Torr. We then use a discrete element method (DEM) to obtain the realistic packing structure of the particles, which is then fed into a finite-element model (FEM) to calculate the thermal conductivity, with the consideration of solid conduction, gas conduction, and radiation heat transfer. Our results show that the thermal conductivity model based on the more realistic random packing structure derived from the DEM shows better agreement with the experimental data compared to that based on the simple cubic-packing structure. The combined DEM and FEM methodology can serve as a useful tool to predict the effective thermal conductivity of particle beds and to quantify different heat transfer mechanisms under various conditions. [ABSTRACT FROM AUTHOR]

• A reversible redox-induced order-disorder transition (ODT) is discovered. • A 10-component single-phase ordered pyrochlore oxide is stable at 1600 °C in air. • Reduction at 1600 °C induces an ODT to form single-phase disordered fluorite oxide. • Re -oxidation at 1600 °C reverses the ODT to form single-phase ordered pyrochlore. • In-situ neutron diffraction reveals the mechanism of oxygen vacancy induced ODT. This study discovers a reversible order-disorder transition (ODT) in a 10-component compositionally complex ceramic, (Nd 0.15 Pr 0.15 Dy 0.8 Ho 0.8 Er 0.8 Ti 0.2 Yb 0.1 Hf 0.1 Zr 0.1 Nb 0.8)O 7-δ , induced via annealing in oxidized vs. reduced environments at 1600 °C. Notably, the 10-cation oxide remains a homogenous single-phase high-entropy solid solution before and after the ODT in the pyrochlore vs. fluorite structure that can be quenched. In-situ neutron diffraction reveals the oxygen vacancy formation and atomic displacement during this ODT. This study reveals a new pathway to induce ODT via a redox transition to tailor the properties of compositionally complex fluorite-based oxides. [Display omitted] [ABSTRACT FROM AUTHOR]

Background& Aims: Hepatosteatosis, defined as excessive intrahepatic lipid accumulation, represents the first step of NAFLD. When combined with additional cellular stress, this benign status progresses to local and systemic pathological conditions such as NASH and insulin resistance. However, the molecular events directly caused by hepatic lipid build-up, in terms of its impact on liver biology and peripheral organs, remain unclear. Carnitine palmitoyltransferase 1A (CPT1A) is the rate limiting enzyme for long chain fatty acid beta-oxidation in the liver. Here we utilise hepatocyte-specific Cpt1a knockout (LKO) mice to investigate the physiological consequences of abolishing hepatic long chain fatty acid metabolism.Approach& Results: Compared to the wild-type (WT) littermates, high fat diet (HFD)-fed LKO mice displayed more severe hepatosteatosis but were otherwise protected against diet-induced weight gain, insulin resistance, hepatic ER stress, inflammation and damage. Interestingly, increased energy expenditure was observed in LKO mice, accompanied by enhanced adipose tissue browning. RNAseq analysis revealed that the peroxisome proliferator activator alpha (PPARα)- fibroblast growth factor 21 (FGF21) axis was activated in liver of LKO mice. Importantly, antibody-mediated neutralization of FGF21 abolished the healthier metabolic phenotype and adipose browning in LKO mice, indicating that the elevation of FGF21 contributes to the improved liver pathology and adipose browning in HFD-treated LKO mice.Conclusions: Liver with deficient CPT1A expression adopts a healthy steatotic status that protects against HFD-evoked liver damage and potentiates adipose browning in an FGF21-dependent manner. Inhibition of hepatic CPT1A may serve as a viable strategy for the treatment of obesity and NAFLD. [ABSTRACT FROM AUTHOR]

• The first in-situ thermal conductivity measurement of flowing molten chloride salt. • Non-contact modulated photothermal radiometry for high-temperature measurement. • Increased effective thermal conductivity of flowing salt due to convection. • Heat transfer coefficient is obtained from experiments and Gnielinski's correlation. Molten salts are leading candidates for high-temperature heat transfer fluids (HTFs) for thermal energy storage and conversion systems in concentrated solar power (CSP) and nuclear energy power plants. The ability to probe molten salt thermal transport properties in both stationary and flowing status is important for the evaluation of their heat transfer performance under realistic operational conditions, including the temperature range and potential degradation due to corrosion and contamination. However, accurate thermal transport properties are usually challenging to obtain even for stagnant molten salts due to different sources of errors from convection, radiation, and corrosion, let alone at flowing status. To the best of authors' knowledge, there is no available in-situ technique for measuring flowing molten salt thermal conductivity. Here, we report the first in-situ flowing molten salt thermal conductivity measurement using modulated photothermal radiometry (MPR). We could successfully perform the first in-situ thermal conductivity measurement of flowing molten NaCl-KCl-MgCl 2 in the typical operating temperature (520 and 580 °C) with flow velocities ranging from around 0.3 to 1.0 m s−1. The relative change of the molten salt thermal conductivity was measured. Gnielinski's correlation was also used to estimate the heat transfer coefficient h of the flowing NaCl-KCl-MgCl 2 in the given experimental condition. The work showed the potential of the MPR technique serving as an in-situ diagnostics tool to evaluate the heat transfer performance of flowing molten salts and other high-temperature HTFs. [ABSTRACT FROM AUTHOR]

Persistent, unresolved inflammation in adipose tissue is a major contributor to obesity-associated metabolic complications. However, the molecular links between lipid-overloaded adipocytes and inflammatory immune cells in obese adipose tissues remain elusive. Here we identified adipocyte-secreted microRNA-34a (miR-34a) as a key mediator through its paracrine actions on adipose-resident macrophages. The expression of miR-34a in adipose tissues was progressively increased with the development of dietary obesity. Adipose-selective or adipocyte-specific miR-34a-KO mice were resistant to obesity-induced glucose intolerance, insulin resistance, and systemic inflammation, and this was accompanied by a significant shift in polarization of adipose-resident macrophages from proinflammatory M1 to antiinflammatory M2 phenotype. Mechanistically, mature adipocyte-secreted exosomes transported miR-34a into macrophages, thereby suppressing M2 polarization by repressing the expression of Krüppel-like factor 4 (Klf4). The suppressive effects of miR-34a on M2 polarization and its stimulation of inflammatory responses were reversed by ectopic expression of Klf4 in both bone marrow-derived macrophages and adipose depots of obese mice. Furthermore, increased miR-34a expression in visceral fat of overweight/obese subjects correlated negatively with reduced Klf4 expression, but positively with the parameters of insulin resistance and metabolic inflammation. In summary, miR-34a was a key component of adipocyte-secreted exosomal vesicles that transmitted the signal of nutrient overload to the adipose-resident macrophages for exacerbation of obesity-induced systemic inflammation and metabolic dysregulation. [ABSTRACT FROM AUTHOR]

Abstract Transparent wood is an environmentally friendly material that could be used as building materials or substrates for solar cells to reduced electrical energy consumption. Many problems remain in the delignification process, such as energy consumption and gas pollution. In this paper, the optimum conditions for two stage delignification of low density balsa wood (Ochroma pyramidale) and high density of basswood (Tilia tuan) were studied. The optimized single layer transparent wood was laminated to produce transparent wood with high thickness. The results showed that the lamination method cut the delignification time in half and improved the dimensional stability of the transparent wood. Optical testing showed that the maximum transmittance of the same direction laminated transparent wood was similar to the single layer transparent wood with the same thickness. The mechanical experiments showed that the transparent basswood had a better tensile strength, which reached 75.12 MPa. Optimizing the process of the transparent wood could greatly reduce the preparation time and the energy consumption, so that mass production of enterprises could become a reality. [ABSTRACT FROM AUTHOR]

In Fig. 3B of article cited above, for images of iWAT and eWAT, the labels "WT" and "LKO" were inadvertently transposed. LKO (Cpt1a knockout) should have been the label for the first set of images of adipose tissue, and WT (wild type) should have been the label for the second set of images. The authors apologize for the error. The online version of the article (https://doi.org/10.2337/db21-0363) has been updated to correct the error. [ABSTRACT FROM AUTHOR]

• First non-contact in-situ thermal conductivity measurement of flowing fluid. • Identify experimental conditions to obtain intrinsic thermal conductivity of fluid. • Demonstrate the technique on water, ethanol, and two types of oils. • Measure oil from room temperature to 170 °C. In situ thermal transport measurement of flowing fluid could be useful for the characterization and diagnosis of practical thermal systems such as fluid heat exchangers and thermal energy storage systems. Despite abundant reports on the ex-situ thermal conductivity measurement of stagnant fluids, a suitable technique for the thermal conductivity measurement of flowing fluid has been rarely reported. This paper presents the thermal conductivity measurement of flowing fluid within a pipe using a non-contact modulated photothermal radiometry (MPR) technique, where the surface of the pipe is heated by an intensity-modulated laser and the heat diffuses into the fluid with suitable modulation frequency. We design a tube section with small wall thickness suitable for the MPR measurements to maximize the sensitivity of the thermal response to the fluid properties while minimizing the lateral heat spreading effect. Intrinsic thermal conductivity of different fluids was obtained within a proper range of frequency and flow velocity where the forced convection effect is negligible. The forced convection effect became prominent at high flowing velocity and at low modulation frequency, leading to higher effective thermal conductivity of the fluid. It is found that the intrinsic thermal conductivity could be obtained when the flow velocity is less than 100 mm/sec and Re D 1/2Pr1/3 < 100 for DI water and Xceltherm oil under the specified experimental conditions, where R e D is the Reynolds number and P r is the Prandtl number. [ABSTRACT FROM AUTHOR]

A systematic study was performed to measure the effective thermal conductivity of ceramic particle beds, a promising heat transfer and thermal energy storage medium for concentrating solar power (CSP). The thermal conductivity of the ceramic particle beds was measured using a transient hot-wire (THW) method within a temperature range of room temperature to 700 °C, the target operating temperature of the next-generation CSP systems. Two different types of ceramic particles were examined: (1) CARBOBEAD HSP 40/70 and (2) CARBOBEAD CP 40/100 (also known as ACCUCAST ID 50) with the average particle sizes of ~405 μm and ~275 μm, respectively, and thermal conductivities ranging from ~0.25 W m−1 K−1 to ~0.50 W m−1 K−1 from 20 °C to 700 °C in both air and N 2 gas. The gaseous pressure dependence of the thermal conductivity of the ceramic particle beds was also studied in the N 2 environment to differentiate the contributions from gas conduction, solid conduction, and radiation. Calculations using the Zehner, Bauer, and Schlünder (ZBS) model showed good agreements with the measurements. Based on the model, it is concluded that the effective thermal conductivity of the packed particle beds is dominated by the gas conduction while the solid conduction and radiation contributes to about 20% of the effective thermal conductivity at high temperature. • First thermal conductivity measurement of CARBOBEAD HSP 40/70 and CP 40/100 up to 700 °C. • Analysis of thermal conductivity from temperature and gaseous pressure dependence. • Quantification of relative contributions from gas, solid contacts, and radiation at various temperature. • Gaseous conduction is found to be the dominant mechanism. [ABSTRACT FROM AUTHOR]