Search

Solar‐induced thermal challenges in buildings, cold chain logistics, and spacecrafts may be overcome by integrating passive radiative cooling (PRC) with aerogels having thermal insulation (TI). Herein, a universal radiative cooling silica aerogel (UCSA) is prepared through the simple regeneration and freeze‐drying of commercial quartz fiber membranes. The optically engineered UCSA with a hybrid structure (silica nanofibers/microbeads) achieves remarkable solar reflectance (RS.E. = 98.1%) and atmospheric transparency window emittance (εATW = 92.1%) under Earth conditions, with a theoretical daytime cooling power of 103.3 W m−2. In the harsh space environment, it exhibits ultrahigh average solar reflectance (RS.E. = 99.1%) and broadband mid‐infrared emittance (εMIR = 90%), achieving a cooling power of 354.1 W m−2. Compared to single‐functional approaches, UCSA synergistically integrates the PRC and TI performance for excellent thermal management capability. Moreover, this ceramic aerogel can resist temperatures up to 830 °C, safeguarding building occupants and spacecraft electronics. Furthermore, UCSA passes environmental aging and thermal vacuum outgassing tests for long‐term viability both on Earth and in space. Finally, a USCA‐covered box achieves an average sub‐ambient cooling of 18.6 °C when exposed to sunlight. In summary, UCSA opens a path for energy‐efficient and sustainable cooling strategy with universal applications. [ABSTRACT FROM AUTHOR]

This study aims to fully evaluate the radiation effect in existing cooling systems. The research, a combination of experimental analysis and numerical simulations using ANSYS Fluent, examines the complexity of radiative cooling processes and their impact on thermal management in various engineering applications. The experiments began by carefully placing a 112.5 W heater into the thermal channel. Next, temperature measurements were made under various conditions. In particular, the use of black cotton fabric as the inner duct lining applied in the thermal channel stands out as an innovation that aims to optimize heat absorption by increasing radiative properties. The findings highlight the significant impact of radiation on cooling performance. A temperature drop of 2–3°C was observed in cooling under the effect of radiation. Additionally, numerical simulations reveal the feasibility of radiative cooling systems by providing valuable information about the flow dynamics and heat transfer mechanisms within the channel. The novelty of this work is its detailed examination of radiative cooling effects and its focus on its potential to optimize thermal management strategies in various engineering applications. Explaining the role of radiation in heat transfer and providing practical information to improve cooling efficiency demonstrates that this research brings important insight and lays the foundation for future advances in the field. Considering the urgent need for energy‐efficient cooling solutions and the increasing demand for sustainable engineering practices, the findings of this study will provide important insights for researchers and practitioners. This study provides innovative perspectives and solutions to address the increasing challenges of heat transfer and energy conservation in engineering systems. It makes a significant contribution to the field of thermal management by offering methodologies. [ABSTRACT FROM AUTHOR]

Post‐exercise hot (HWI) and cold (CWI) water immersion are popular strategies used by athletes in a range of sporting contexts, such as enhancing recovery or adaptation. However, prolonged heating bouts increase neuroendocrine responses that are associated with perceptions of fatigue. Fourteen endurance‐trained runners performed three trials consisting of two 45‐min runs at 95% lactate threshold on a treadmill separated by 6 h of recovery. Following the first run, participants completed one of HWI (30 min, 40°C), CWI (15 min, 14°C) or control (CON, 30 min rest in ambient conditions) in a randomised order. Perceived effort and recovery were measured using ratings of perceived exertion (RPE) and the Acute Recovery and Stress Scale (ARSS), whilst physiological responses including venous concentrations of a range of neuroendocrine markers, superficial femoral blood flow, heart rate and rectal temperature were measured. Exercise increased neuroendocrine responses of interleukin‐6, adrenaline and noradrenaline (all P < 0.001). Additionally, perceptions of overall recovery (P < 0.001), mental performance capacity (P = 0.02), physical performance capability (P = 0.01) and emotional balance (P = 0.03) were reduced prior to the second run. However, there was no effect of condition on these variables (P > 0.05), nor RPE (P = 0.68), despite differences in rectal temperature, superficial femoral blood flow following the first run, and participants' expected recovery prior to the intervention (all P < 0.001). Therefore, athletes may engage in post‐exercise hot or cold‐water immersion without negatively impacting moderate‐intensity training sessions performed later the same day. What is the central question of this study?Does post‐exercise heating or cooling alter recovery and perception of effort during subsequent exercise?What is the main finding and its importance?Neither post‐exercise heating nor post‐exercise cooling altered perceived recovery or perception of effort during subsequent exercise, despite heating inducing large increases in blood flow to the lower limbs. Contrary to our hypotheses, neither heating nor cooling had any impact on inflammatory or neuroendocrine responses in plasma. Post‐exercise heating does not appear to exacerbate fatigue as previously suggested in other studies. [ABSTRACT FROM AUTHOR]

In this paper, the seeded batch cooling crystallization of sodium phosphite (SP) is simulated and optimized through a coupled method of the genetic algorithm and nonlinear programming. At first, the modeling and simulation test methods of the crystallization process are applied for the crystallization of SP, which expands the relevant study of SP from the experiment to the simulation. A comprehensive model is established in MATLAB/Simulink, and based on this model, the results of the common cooling strategy (linear cooling) on the process are investigated. Meanwhile, the process sensitivity to the change of seeding conditions is analyzed. Then, the coupled optimization method based on the genetic algorithm and nonlinear programming is applied to optimize the crystallization process for the first time, and the obtained optimized cooling strategy is compared to the result of the traditional nonlinear programming method (NLPM). The traditional NLPM has more significant effects on large seeding mass and small mean size, while the coupled method has better adaptability. When the coefficient of variation is almost fixed, the cooling strategy obtained by the coupled method could produce more crystals with large mean size. In addition, the end of the process can be reached earlier. The results show that the coupled method is more suitable for the optimization of the batch cooling crystallization of SP. [ABSTRACT FROM AUTHOR]

This perspective provides an overview of the state of research and innovation in the areas of magnetocaloric and pyromagnetic materials, and electrocaloric and pyroelectric materials, including the overlapping sub‐areas of multicaloric and multipyro materials that can operate simultaneously under the application of magnetic and electric fields. These materials are critically examined for their potential to revolutionize cooling, heating, and energy‐harvesting applications. This perspective first summarizes the state‐of‐the‐art advancements and highlights recent significant developments. Then, it is identified and discussed that the prevailing challenges hindering the widespread adoption of technologies based on these materials. In this context, after consulting with members of the caloric and pyro communities, a technology roadmap is outlined to guide research efforts in overcoming current barriers to applications, with the goal of achieving impactful results by 2040. This roadmap emphasizes the importance of focusing on under‐researched materials, novel devices, and application spaces, paving the way for interdisciplinary efforts that can lead to significant reductions in carbon dioxide emissions. [ABSTRACT FROM AUTHOR]

Forecasting warm‐sector rainfall (WR) remains a major challenge, primarily due to weak synoptic forcing. Through cloud‐permitting numerical simulations, in addition to direct triggering mechanism from low‐level jets, we identify the important role of gravity waves in a heavy WR event in South China via convective preconditioning. The preconditioning manifests as mid‐level moistening and destabilization with wave‐like variations. This process is driven by fast‐propagating (∼24 m s−1) n = 2 waves, associated with lower‐tropospheric ascents and upper‐tropospheric descents. Waves are generated during the evolution of northern frontal rainfall (FR). As FR intensifies, surges in low‐level diabatic cooling mainly resulting from microphysical processes, trigger n = 2 waves, which further precondition the environment along their path. In contrast, a sensitivity experiment involving stably developing FR fails to reproduce the preconditioning process by waves and the subsequent occurrence of WR. Overall, our study illuminates a new pathway through which FR significantly influences WR via gravity waves. Plain Language Summary: During the rainy season, the coastal regions of South China frequently experience heavy rainfall, leading to significant socio‐economic losses. Unfortunately, understanding the mechanisms underlying this heavy rainfall and accurately predicting it remains a great challenge, as it often occurs without evident synoptic influences such as fronts and low‐pressure vortex. Another rainband occasionally forms to the north of the coastal heavy rainfall through frontal lifting. The northern inland frontal rainfall could be considered a potential contributor to the initiation of coastal heavy rainfall, yet no concrete connection has been established until now. Our research reveals that this frontal rainband can generate low‐frequency gravity waves that have a substantial influence on coastal heavy rainfall. These waves primarily result from the sharp cooling associated with the frontal rainband, featuring lower‐tropospheric upward motions. They are capable to travel considerable distances ahead of the frontal rainband at high speeds. Along their journey, they moisten and destabilize the cloud environment ahead of the frontal rainband, thereby favoring the occurrence of coastal rainfall. Key Points: The initiation of warm‐sector heavy rainfall at the coast is related to the evolution of northern frontal rainfall that located 300 km awayVariations in latent cooling resulting from the frontal rainfall produce gravity waves featuring ascents over the lower troposphereThese gravity waves moisten and destabilize mid‐level environment along their paths, promoting warm‐sector rainfall [ABSTRACT FROM AUTHOR]

Passive radiative cooling represents a transformative approach to achieving sustainable cooling on Earth without relying on energy consumption. In this research, the optical characteristics of five readily accessible metal‐organic frameworks (MOFs): ZIF‐67(Co), MOF‐74(Ni), HKUST‐1(Cu), MOF‐801(Zr), and UiO‐66(Zr) are meticulously explored. The objective is to identify the pivotal factors that influence their ability to facilitate radiative cooling. Through an in‐depth analysis encompassing spectroscopic features, surface texture, and porosity, it is found that the MOFs' cooling efficacy is largely influenced by their optical bandgaps and functional groups, although other factors like chemical composition and structural characteristics remain to be considered. Notably, UiO‐66(Zr) emerged as the standout performer, boasting an impressive solar reflectance of 91% and a mid‐infrared emissivity of 96.8%. Remarkably, a fabric treated with UiO‐66(Zr) achieved a substantial sub‐ambient cooling effect, lowering temperatures by up to 5 °C and delivering a cooling power of 26 W m−2 at 300 K. The findings underscore the vast potential of MOFs in offering new opportunities to advance passive radiative cooling technologies, paving the way for their extensive application in this field. [ABSTRACT FROM AUTHOR]

Daytime radiative cooling (DRC) has emerged as a promising method for temperature reduction of surfaces exposed to sunlight, without energy consumption. Despite advancements in DRC design, existing reflector‐based methodologies often lack transparency because of visible reflection, hindering the widespread application of this technology using glass. Efforts to address this challenge have led to the development of transparent radiative cooling (TRC), although efficient cooling during daylight remains challenging because of the dominant solar energy absorption. This paper proposes a novel TRC design comprising a polydimethylsiloxane (PDMS) emitter atop a transparent dual‐reflector structure. An optimized Bragg reflector (OBR) and a 90 µm‐hole‐punctured Ag window screen reflector (WR) are used to reflect band A of the near‐infrared (NIR) spectrum (0.74 < λ < 1.4 µm) and the overall solar spectrum, respectively. During the daytime, the proposed TRC lowers the temperature by 22.1 °C through the transparent dual reflector system, compared to a PDMS‐coated glass. Thus, this approach optimizes the balance between solar reflection and visibility using a dual reflector, offering an optimal solution for applications requiring both cooling and transparency. [ABSTRACT FROM AUTHOR]

The Late Pleistocene Marine Isotope Stage (MIS) 5 – MIS 4 transition (at ca. 75 ka) is globally known to correspond to a period of strong cooling and sea‐level lowering. Terrestrial records indicate the transition had a large impact on terrestrial environments, but the impact on coastal and shallow‐marine areas is poorly documented due to a lack of well‐dated, continuous archives caused by erosion during succeeding glacial lowstands. The extensive offshore deposits of the Brown Bank Formation in the southern North Sea yield a valuable record of this transition in a shallow‐marine environment. We show that the southern North Sea experienced subarctic marine conditions with a high input of terrestrial material during the MIS 5–4 transition. These continued marine conditions, which have not been described earlier for northwestern Europe, show that sea level remained relatively high, and lagged cooling on land inferred from lipid‐biomarker palaeothermometry. The time‐lag between terrestrial cooling and sea‐level fall created a sediment preservation window during the onset of MIS 4 in a shallow‐marine environment. Our record captures changes in both the terrestrial and shallow‐marine environments, and allows for linking terrestrial and marine records of the MIS 5–4 transition in NW Europe. [ABSTRACT FROM AUTHOR]

Metal halide perovskite (MHPs) nanocrystals (NCs) have recently emerged as promising materials for optoelectronic applications due to their exceptional photophysical properties. A comprehensive understanding of the underlying principles and key challenges associated with controlling the hot carrier (HC) cooling dynamics in MHPs is pivotal for the design of efficient perovskite‐based optoelectronic applications. This review highlights the general carrier cooling mechanism and identifies influencing crucial controlling parameters for carrier dynamics. The discussion includes strategies for manipulating HC cooling dynamics through carrier‐phonon and carrier‐carrier interactions. Notably, recent advancements in HC extraction with suitable acceptors are explored, as efficient HC extraction is imperative for the advancement of optoelectronic applications. The objective of this review is to outline potential pathways for strategically modifying carrier cooling processes to align with specific optoelectronic applications. A profound comprehension of charge carrier dynamics in MHPs NCs will pave the way for the development of highly efficient optoelectronic applications. [ABSTRACT FROM AUTHOR]

Time series of radiative cooling of the upper mesosphere and lower thermosphere (UMLT) by carbon dioxide (CO2) are examined for evidence of trends over 20 years. Radiative cooling rates in K day−1 provided by the SABER instrument are converted to time series of infrared power radiated from three distinct layers between 0.1 hPa and 0.0001 hPa (65–105 km). Linear regression against time and a predictor for solar variability provides estimates of the trend in exiting longwave radiation (ELR) from these layers. Trends in ELR are not significantly different from zero at 95% or 99% confidence in each layer. These results demonstrate energy conservation in the UMLT on decadal time scales and show that the UMLT continues to radiate the same amount of energy it receives despite cooling and contracting over two decades. These results are enabled by the long‐term stability of the SABER instrument calibration. Plain Language Summary: The Earth's upper mesosphere and lower thermosphere (UMLT) is the region between approximately 65 and 105 km in altitude. Infrared radiation emitted by CO2 is a fundamental component of the energy budget of the UMLT. Carbon dioxide (CO2) is increasing in this region. The amount of infrared energy emitted by CO2, over time, must balance the amount of energy from sunlight that is absorbed in the UMLT. Observations from orbiting satellites over the past two decades have shown that the temperature in the UMLT is decreasing due to the increasing CO2. A decreasing temperature implies a decrease in infrared energy emitted by an object. Energy conservation, however, requires that the amount of infrared energy radiated from the UMLT balance the amount of energy received, regardless of the temperature. In this paper we show that there is no significant long‐term change with time (i.e., zero trend) in the infrared energy emitted from the UMLT even though the UMLT temperature has been decreasing for the last 20 years (and longer) due to increasing CO2. This result confirms that energy is conserved in a cooling and contracting UMLT. Key Points: Time series of infrared power (W) radiated by CO2 from the upper mesosphere & lower thermosphere (UMLT) are developedTrends in radiated power are not different from zero at 95% or 99% confidence in the three layers examined between 0.1 and 0.0001 hPaIncreasing CO2 reduces the UMLT temperature while radiating the same amount of energy over time, thus conserving energy [ABSTRACT FROM AUTHOR]

Recently, passive radiative cooling (PRC) that realizes thermal management without consuming any energy has attracted increasing attention. However, few studies focus on low‐cost and robust PRC film fabricated by a facile and environmentally friendly method. In this study, via coextrusion blow film molding and water leaching, sandwiched PRC film (SPRCF) is efficiently prepared, and its skin and core layer are respectively high‐density polyethylene (HDPE) film and oriented ZnO@HDPE microfiber layer. Of note, such a sandwiched structure enables SPRCF to possess remarkable mechanical properties, abrasion, and weather resistance. Moreover, with the introduction of ZnO, SPRCF shows lower sunlight transmittance (≈3.8%) but higher mid‐infrared transmittance (≈88.8%), endowing it with remarkable PRC performance (the maximum cooling power of daytime and nighttime are respectively 73.8 and 96.7 W m−2). Furthermore, the decent self‐cleaning performance of SPRCF‐45 endows it with maintenance‐free features outdoors. This work proposes a facile and environmentally friendly method for preparing low‐cost and robust SPRCF, opening a new pathway to develop PRC film following the concept of polymer "structuring" processing. [ABSTRACT FROM AUTHOR]

Passive daytime radiative cooling has emerged as a promising green technology for the thermal management of buildings, vehicles, textiles, and electronics. Typically, both high solar reflectance and high thermal emissivity are prerequisites to achieve sufficient daytime cooling. However, colored radiative cooling materials are facing the dilemma of introducing visible light absorption, leading to challenges in balancing cooling and aesthetic demands. Here, three colored bilayer radiative cooling coatings, each comprised of a white base layer and a colored top layer with fluorescence enhancement are fabricated. Three phosphors (Sr2Si5N8:Eu2+, Y3Al5O12:Ce3+, and (Ba,Sr)SiO4:Eu2+) are employed with respective photoluminescence quantum yields (PLQYs) of 81%, 95.8%, and 91.0% as the colored pigment in the top layer. To mitigate the contradiction between coloration and solar reflectance, SiO2 microspheres are introduced into the top layer and utilize their Mie‐resonance‐based multiple scattering to increase the photoluminescent (PL) properties of the phosphors, which jointly boosts the effective solar reflectance (ESR) of the top layer. As a result, the three bilayer coatings exhibit soft colors while achieving subambient cooling with temperature drops of up to 1.5 °C. This fluorescence‐enhancement strategy may pave the way for preparing highly efficient radiative cooling coatings with tunable colors. [ABSTRACT FROM AUTHOR]

The authors investigate a semi‐flooded cooling technology for modular permanent magnet machines using flux gaps (FGs) in alternate stator teeth for extra cooling channels. The investigated machine is separated into stationary and rotational components by a polyether ether ketone sleeve. Liquid is directed into the stationary component to achieve a significant temperature reduction, at the same time, avoiding the liquid leakage into the rotating component that will cause an increase in friction losses. The FGs in the modular machine increase the contact area between coolant and machine components, resulting in better cooling efficiency. Furthermore, the FGs contribute to reduced pressure loss by minimising system flow resistance. The influence of the FG width on improving machine cooling efficiency, lowering machine temperature, and reducing pressure losses is delved. Additionally, the investigation considers the impact of inlet and outlet areas to reveal the influences stemming from fluid expansions and contractions in these regions. Computational fluid dynamics (CFD) modelling is employed to simulate the cooling performances of the investigated machines. In addition, the flow network analysis has also been employed to help understand the fluid behaviour within machines. A series of tests have been carried out to validate the CFD modelling. [ABSTRACT FROM AUTHOR]

To maintain a comfortable indoor living environment in low latitude or tropical regions, humans consume significant amounts of electrical energy in air conditioning, leading to substantial CO2 emissions. Passive daytime radiative cooling (PDRC) allows objects to cool down during the daytime without any energy consumption by dissipating heat through the atmospheric transparency window (8−13 µm) to outer space, which has garnered significant attention. However, the practical applications of common PDRC materials are hindered by their poor optical selectivity and high‐reflective silver backing. Additionally, the availability of artificial photon emitters with complex structures and excellent performance is also limited by their high cost. Herein, a novel multilayer prismatic photonic metamaterial film without any silver reflector, easily scalable and produced by a roll‐to‐roll method is demonstrated, which exhibits ≈96.4% sunlight reflectance (0.3−2.5 µm) and ≈97.2% emissivity in mid‐infrared (IR) (8−13 µm). At an average solar intensity of ≈920 W m−2, it is on average 6.8 °C below ambient temperature during the day and theoretically yields a radiative cooling power of 88.9 W m−2. Furthermore, the film exhibits excellent hydrophobicity, superior flexibility, and robust mechanical strength, providing an attractive and viable pathway for practical applications addressing the pressing challenges of climate and energy issues. [ABSTRACT FROM AUTHOR]

Objective: Focal cooling is emerging as a relevant therapy for drug‐resistant epilepsy (DRE). However, we lack data on its effectiveness in controlling seizures that originate in deep‐seated areas like the hippocampus. We present a thermoelectric solution for focal brain cooling that specifically targets these brain structures. Methods: A prototype implantable device was developed, including temperature sensors and a cannula for penicillin injection to create an epileptogenic zone (EZ) near the cooling tip in a non‐human primate model of epilepsy. The mesial temporal lobe was targeted with repeated penicillin injections into the hippocampus. Signals were recorded from an sEEG (Stereoelectroencephalography) lead placed 2 mm from the EZ. Once the number of seizures had stabilized, focal cooling was applied, and temperature and electroclinical events were monitored using a customized detection algorithm. Tests were performed on two Macaca fascicularis monkeys at three temperatures. Results: Hippocampal seizures were observed 40–120 min post‐injection, their duration and frequency stabilized at around 120 min. Compared to the control condition, a reduction in the number of hippocampal seizures was observed with cooling to 21°C (Control: 4.34 seizures, SD 1.704 per 20 min vs Cooling to 21°C: 1.38 seizures, SD 1.004 per 20 min). The effect was more pronounced with cooling to 17°C, resulting in an almost 80% reduction in seizure frequency. Seizure duration and number of interictal discharges were unchanged following focal cooling. After several months of repeated penicillin injections, hippocampal sclerosis was observed, similar to that recorded in humans. In addition, seizures were identified by detecting temperature variations of 0.3°C in the EZ correlated with the start of the seizures. Significance: In epilepsy therapy, the ultimate aim is total seizure control with minimal side effects. Focal cooling of the EZ could offer an alternative to surgery and to existing neuromodulation devices. [ABSTRACT FROM AUTHOR]

In this paper, the effect of p–n heterostructures on the electro‐optical and heat regulation performances of polymer dispersed liquid crystal (PDLC) dimming films are studied. In detail, the WO3, Ag2O, and WO3/Ag2O p–n heterostructures are successfully synthesized via the co‐precipitation method. The products are analyzed by XRD, SEM, TEM, and XPS and the results demonstrated that the WO3 nanorods successfully grew on the surface of Ag2O. Compared to the primitive sample, the incorporation of p–n heterostructures into the composite films significantly enhances the electro‐optical properties. For a 20µm‐thick film, the saturation voltage (Vsat) decreases by 38.7% from 24.8 to 15.2 V, and the threshold voltage (Vth) is reduced by 22.9% from 12.7 to 9.8 V, while the contrast ratio reaches 132. Due to the molecular structure of the polymer monomers and the micro‐network structure of the film, the film exhibits high emissivity in the mid infrared spectrum, enabling enhanced dynamic cooling management through radiative cooling around the clock. Matrix & laboratory (MATLAB) calculations show that the maximum cooling power during the day and night reached 97.63 and 136.24W m‐2 K‐1, respectively. This research has great significance for the development of highly energy‐efficient smart windows. [ABSTRACT FROM AUTHOR]

Passive radiative cooling is a zero‐energy consumption approach, which can dissipate heat to outer space by emitting infrared radiation through the transparency window. Traditional cooling materials, such as photonic films, metafabrics, and polymer foams, still suffer from complex preparation processes and high costs. In this work, it is reported that natural cellulose can be converted into a “green” optical metamaterial by rational structure reconfiguration at the micro/nano level via scalable ball milling technology for efficient daytime radiative cooling. Specifically, fine‐tuning the shearing kinetics in the mechanochemistry process, cellulosic optical metamaterial (COM) with ≈98% solar reflectivity and ≈0.97 infrared emissivity has been successfully achieved, which can break through the theoretical value of photonic crystals as well as the conventional synthetic optical materials. The COMSOL simulation reveals that the excellent optical properties of the cellulose metamaterial are explained by the “confined scattering” effect caused by the rearranged heterostructure at the micro/nano level. Outdoor tests demonstrat that the COM‐based coating exhibits a daytime radiative cooling efficiency of 5.7 °C in hot Nanjing. Meanwhile, the COM can be produced into different scattering materials via spray coating, freeze casting, and solution casting technology. This study will facilitate the development of scalable and sustainable optical metamaterials for mitigating energy consumption. [ABSTRACT FROM AUTHOR]

In recent years, passive radiative cooling has garnered considerable attention as a sustainable thermal regulation without relying on external energy sources, thus mitigating pollutants generation. However, an intrinsic limitation of these cooling systems lies in the reflective glare, often characterized by an ivory or silvery appearance. This drawback limits their practical application, especially where both functional efficiency and aesthetic appeal are pivotal. Herein, a biomimetic approach inspired by Saharan silver ants' thermoregulatory capabilities is adopted. These ants, equipped with distinctive triangular‐shaped hair, maintain body temperature lower than the ambient air. Leveraging insights from this natural model, a reusable silicon template is employed to fabricate a metasurface structural colored film with a triangular prism array structure using thermoplastic polyurethane (TPU) and the phase separation technique. The film demonstrates an average emissivity of 96% within the atmospheric window and an average solar reflectivity of 93%, leading to a maximum temperature reduction of 8.6 °C during daytime and 5.9 °C at night. Furthermore, the film displays stretchability and mechanical resilience, bolstered by the microscale prismatic structure enhancing superhydrophobicity. This work introduces a biomimetic strategy aimed at augmenting thermal emission while reconciling the challenge of achieving visual appealand high radiative cooling performance. [ABSTRACT FROM AUTHOR]

Global climate crises are the most significant challenges to be solved these days. As one of the technological endeavors to tackle the issue, radiative cooling is amongst the most attractive approaches for sustainable heat energy regulation, which involves maximizing solar heat reflection and thermal heat emission. These green technologies inevitably require architectural applicability, considering that building facades take a large proportion of the heat‐radiating surfaces. For mass‐production suitability and durability, radiative coolers (RCs) fabricated in a fully ceramic context are recently suggested, featuring scalable, thermally insulative, and non‐shrinking advantages. However, the visual effects are also imperative for architectural instances but are seldom accounted for. In this context, this article suggests the enhanced color‐preserving radiative cooling (ECRC) structure for practical architectural applications of glass‐infiltrated ceramic RCs. By simply blending ceramic pigment into the uppermost porous alumina layer, the ECRC structure can maintain the physical, and thermal features of all‐ceramic RC, while exhibiting color by visible reflectance adjustment. ECRCs exhibit an additional cooling performance of up to ≈17.3 °C depending on their color, compared to their conventional counterparts. With additional chromatic features, ECRC can further enhance the availability of radiative cooling technology for practically realizing the energy‐saving structures in real‐world architectural circumstances. [ABSTRACT FROM AUTHOR]

Silk fibroin (SF) is a natural biomaterial from silk, which has outstanding biocompatibility. However, regeneration SF materials usually suffer from brittleness, which restricts their applications. Here, a novel supramolecular co‐assembly strategy is reported for the preparation of a Bolas‐shaped polyethylene glycol peptide (BPP)/SF film, where the peptide and SF form a robust payload co‐assembled network and polyethylene glycol (PEG) fragments form supramolecular cross‐linking in this network. The obtained BPP/SF film shows both high stress (27.8 MPa), high toughness (3.64 MJ m−3), high transparency (89%), and high mid‐infrared (MIR) emissivity (90.5%). In passive radiative cooling, the BPP/SF film results in a 2.7 °C reduction in the temperature of the human arm skin and a 14.6 °C reduction in the temperature of the solar cell. More importantly, this novel BPP co‐assembly SF material can be recycled and reused while maintaining its original mechanical strength. This work provides a novel strategy for fabricating regenerative SF materials with ultra‐strong and ultra‐tough mechanical performance. [ABSTRACT FROM AUTHOR]

Building integrated photovoltaic modules, applied to industrial and commercial buildings, generally used metal as the backsheet. In summer, the operating temperature of modules is as high as 70°C, resulting in instability of output power and service life. Therefore, it is very important to reduce the operating temperature of photovoltaic modules. In this work, Al2O3/graphene/poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) composite radiative cooling coatings were prepared and utilized for reinforcing heat dissipation of photovoltaic modules. The results indicate that 0.75 wt%Al2O3/1wt%graphene/PVDF‐HFP composite coating exhibited a thermal diffusivity of 3.24 μm2/s and an average emissivity of 0.94. The maximum temperature drop of the coating in the outer door reached 5.8°C. In addition, a mini photovoltaic module coated with the composite coating achieved the cooling effect of 2.4°C, and the output power and conversion efficiency were increased by 5.8% and 7%, respectively. This demonstrates that the heat conduction radiative cooling coating possesses potential applications for improving the reliability of photovoltaic modules. [ABSTRACT FROM AUTHOR]

Passive daytime radiative cooling dissipates heat from surfaces by reflecting sunlight and emitting infrared radiation to the cold outer space, featuring a zero‐energy consumption. Polymer‐dielectric radiative cooling coatings have received significant attention because of their scalable preparation, low cost, and ease of use. However, current dielectric scatterers reveal limited solar reflectance in the polymer‐dielectric coatings due to the optical crowding, which reduces cooling effect and hinders practical application. Employing a scalable emulsion templated method, reversed yolk–shell dielectric scatterers (RYSS) are developed to alleviate optical crowding effects in polymer‐dielectric coatings. This results in coatings with a solar reflectance of ≈97.4% and an infrared emittance of ≈96.9%, while achieving a substantial reduction in scatterers content. Besides, simulation results show that RYSS outperforms core–shell, hollow, and solid scatterers in enhancing solar reflectance. Using phase change materials as emulsion templates, RYSS with high heat storage effectively enhance daytime cooling and reduce nighttime over‐cooling. Moreover, cooling experiments on concentrating photovoltaics demonstrate a temperature drop of 42 °C (≈26.2 times extension of lifetime) and a notable 22% increase in open‐circuit voltage. This work suggests that RYSS presents a promising solution to overcome the challenges of radiative cooling materials and pave the way for their practical applications. [ABSTRACT FROM AUTHOR]

Passive radiative cooling technologies play an integral role in advancing sustainable development. While the potential of polymer‐based radiative cooling materials is increasingly recognized, they often degrade under prolonged ultraviolet (UV) radiation exposure, which undermines both their mechanical and radiative cooling performance. To address this challenge, a coaxial electrospinning method to prepare a BST@TPU membrane, with a core layer of strontium barium titanate nanorods (BST NRs) and a shell layer of thermoplastic polyurethane (TPU) is employed. Capitalizing on the UV absorption and free radical adsorption properties of BST NRs, the UV stability of the TPU membrane is significantly increased. Additionally, the inclusion of high refractive index BST NRs compensates for the decrease in reflectivity caused by their UV absorption. After 216 h of continuous 0.7 kW m−2 UV irradiation, the BST@TPU membrane, which initially exhibits a reflectance of 97.2%, demonstrated a modest decline to 92.1%. Its net radiative cooling power maintains 85.78 W m−2 from the initial of 125.21 W m−2, extending the useful lifetime of the TPU membrane threefold. This innovation extends promise for enhancing the efficiency and durability of radiative cooling materials, contributing to sustainable cooling solutions across various applications. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate whether cooled anaesthetic eyedrops and antiseptics alleviate pain and minimise subconjunctival haemorrhage following intravitreal injection. Methods: A prospective, double‐masked, randomised controlled trial of 100 participants receiving either cooled (n = 50) or room temperature (n = 50) topical anaesthetic eyedrops and antiseptics before receiving an injection of bevacizumab. Baseline tolerability was estimated using a self‐reported pain sensitivity questionnaire. Results: Overall tolerability was comparable between the study group and the control group (0.75 ± 0.13 vs. 0.74 ± 0.14, respectively, p = 0.99). Subconjunctival haemorrhage incidence was similar in both groups (80% vs. 86%, respectively, p = 0.113), as was subconjunctival haemorrhage size (2.75 ± 5.51 mm2 vs. 5.53 ± 10.72 mm2, respectively, p = 0.11). Sub‐group analysis demonstrated that the participants taking daily ocular eyedrops who received cooled anaesthetic eyedrops and antiseptics reported less pain at 10 min and less burning sensation at 24 h compared with matched controls (0.67 ± 1.50 vs. 2.50 ± 3.03, respectively, p = 0.040 and 0.00 ± 0.00 vs. 1.44 ± 2.96, respectively, p = 0.045). Participants who received cooled eyedrops and did not use antithrombotic therapy had smaller‐sized subconjunctival haemorrhages compared with matched controls (1.55 ± 1.87 mm2 vs. 8.29 ± 14.61 mm2, respectively, p = 0.038). Participants with hypertension who received cooled eyedrops had smaller‐sized subconjunctival haemorrhage compared with matched controls (2.33 ± 4.99 mm2 vs. 6.89 ± 12.41 mm2, respectively, p = 0.045). Conclusion: The benefit of using cooled anaesthetic eyedrops and antiseptics to alleviate pain and minimise subconjunctival haemorrhage following intravitreal injection was not proven in the general population. It may be beneficial in part for some patients, such as those who regularly use eyedrops, patients with hypertension or those not on antithrombotic therapy. [ABSTRACT FROM AUTHOR]

Seeley and Wordsworth (2021, https://doi.org/10.1038/s41586‐021‐03919‐z) showed that in small‐domain cloud‐resolving simulations the temporal pattern of precipitation transforms in extremely hot climates (≥320 K) from quasi‐steady to organized episodic deluges, with outbursts of heavy rain alternating with several dry days. They proposed a mechanism for this transition involving increased water vapor greenhouse effect and solar radiation absorption leading to net lower‐tropospheric radiative heating. This heating inhibits lower‐tropospheric convection and decouples the boundary layer from the upper troposphere during the dry phase, allowing lower‐tropospheric moist static energy to build until it discharges, resulting in a deluge. We perform cloud‐resolving simulations in polar night and show that the same transition occurs, implying that some revision of their mechanism is necessary. We perform further tests to show that episodic deluges can occur even if the lower‐tropospheric radiative heating rate is negative, as long as the magnitude of the upper‐tropospheric radiative cooling is about twice as large. We find that in the episodic deluge regime the period can be predicted from the time for radiation and reevaporation to cool the lower atmosphere. Plain Language Summary: Precipitation plays an important role in Earth's climate and habitability, and also influences important weathering processes such as the carbonate‐silicate cycle. In the distant future, Earth may experience a very hot and wet "hothouse" climate, just like it may have in the Archean. Modeling results show that in a hothouse climate, precipitation transforms into an "episodic deluge" pattern, with outbursts of heavy rain alternating with several dry days. In this study, we find that positive lower‐tropospheric heating is not the necessary cause for episodic deluges. Instead, vertical radiative cooling contrast is critical in triggering the episodic deluges in small‐domain hothouse climates. We also try to understand the underlying mechanism of episodic deluges through CIN and CAPE analyses. Key Points: Episodic deluges can occur during polar nightLower‐tropospheric radiative heating is not necessary for the occurrence of episodic delugesA strong vertical gradient of radiative cooling is a key factor in triggering episodic deluges [ABSTRACT FROM AUTHOR]

The ureilite parent body (UPB) was, in all likelihood, completely broken apart when hit by another object early in its history and reassembled into daughter bodies. We here present a study tailored to constrain the dimensions of the impact debris produced in the catastrophic disruption. Using a customized Python code to simulate the thermal evolution of the UPB fragments, we compared the FeO profiles modeled for different depths within those fragments with those measured across the reduction rims in olivines of 12 different ureilites (n = 37). Our profile data were fitted to the theoretical cooling profiles determined with a transient thermal model. The results are coherent and consistent with earlier studies and, despite using simplified boundary conditions (fragments described as ideal spheres and maximum radiation), our data provide valuable context on possible cooling pathways of the UPB debris. In detail, we found that the average depths within the given fragments from which our samples of ureilites originated were limited to 0.3–0.4 ± 0.1 m, with only few exceptions (e.g., one highly reduced sample lacked suitable reduction profiles suggesting either a depth of origin of >2 m or shielding of this fragment from rapid cooling, e.g., due to hovering in the center of a relatively dense cloud of debris). In addition, we calculated that the cooling from 1473 to 1100 K of the average fragment at the depth of our samples took no more than 3–4 days, suggesting that the reassembly of the ureilite daughter bodies could have been a very fast process. [ABSTRACT FROM AUTHOR]

Personal protective clothing is designed to safeguard medical personnel from highly infectious diseases. However, it often compromises comfort, especially when worn outdoors during epidemics like the global COVID‐19 outbreak. This can lead to discomfort and even heatstroke. To tackle this issue, radiative cooling is incorporated into personal protective clothing by integrating hierarchically porous poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) membranes into the fabric. These membranes possess a remarkable solar reflection rate of 96.9% and a strong mid‐infrared emittance of 95.2%. In practical scenarios, when exposed to clear sunny weather at midday, wearing radiative cooling personal protective clothing has the potential to reduce the temperature by 4.7 °C compared to commercially available personal protective clothing. Moreover, the lamination of porous PVDF‐HFP membranes enhances the protective capacity by increasing the synthetic blood penetration pressure from 7 to 20 kPa. The manufacturing process is straightforward, cost‐effective, and aligns with industry standards, making it suitable for large‐scale implementation in epidemic prevention and control. This technology offers comfortable protection while minimizing the risk of heatstroke. [ABSTRACT FROM AUTHOR]

One impeding factor for faster solidification in typical investment casting processes is the limited heat removal capability. This study compares the classical Bridgman technique and the fluidized carbon bed cooling (FCBC) casting method. In particular, the influence of the thermal design is investigated in terms of microstructural and compositional homogeneity in single-crystalline CMSX-4. These investment casting processes mainly differ in the baffle type used to insulate the hot and cold zones inside of the casting vessel. While the Bridgman process is based on radiation cooling, the FCBC casting process relies on a dynamic baffle made of expanded graphite that is buoyant on fluidized bed of glassy carbon beads. Such a dynamic insulation layer can adapt to the crosssectional variation of ceramic shell molds and provide a better thermal insulation, which results in more uniform solidification conditions. This enables a reduction in the primary dendrite arm spacing by up to 26%, an increase in the homogeneity of the microstructure and composition, as well as a reduction in overall porosity and mean pore size of 41%. [ABSTRACT FROM AUTHOR]

Adsorption cooling and desalination systems have a distinct advantage over other systems that use low‐grade waste heat near ambient temperature. Since improving their performance, including reliability and failure prediction, is challenging, developing an efficient diagnostic system is of great practical significance. The paper introduces artificial intelligence (AI) and an automated machine learning approach (AutoML) in a real‐life application for a computational diagnostic system of existing adsorption cooling and desalination facilities. A total of 1769 simulated data points containing data indicating a failure status are applied to develop a comprehensive AI‐based Diagnostic (AID) system covering a wide range of 42 input parameters. The paper introduces a conditional monitoring system for adsorption cooling and desalination systems. The novelty of the presented study mainly consists of two aspects. First, the intelligent system predicts the health or failure states of various components in a complex three‐bed adsorption chiller installation using the extensive input data sets of 42 different operating parameters. The developed AID expert tool, based on selecting the best from 42 models generated by the DataRobot platform, was validated on the complex, existing three‐bed adsorption chiller. The AID system correctly identified healthy and failure states in various installation components. The developed expert system is very efficient (AUC = 0.988, RMSE = 0.20, LogLoss = 0.14) in predicting emergency states. The proposed method constitutes a quick and easy technique for failure prediction and represents a complementary tool compared to the other condition monitoring methods. [ABSTRACT FROM AUTHOR]

Developing passive radiative cooling fabrics could effectively prevent the harmful consequences of global warming, including heat stress and other related illnesses. By enhancing the material compositions and optimizing the structural parameters of conventional fabrics, the creation of radiative cooling fabric that offers both comfort and durability holds great potential. However, the researched simulation models are over‐simplistic, rendering it challenging to precisely portray the fine fabric's structure with the low accuracy of optical properties prediction. In this work, a high‐fidelity model is developed for fabric structure, which allows for precise control of structural parameters of fiber, yarn, texture, and doping particles. Subsequently, by utilizing the FDTD Solutions software, the optical performance of the fabric model is successfully addressed. Furthermore, the coupled heat transfer equation is employed to determine the actual cooling effect of the fabric. It is observed that doping 1% TiO2 nanoparticles and increasing the number of fibers significantly enhances the solar reflectivity, resulting in a cooling effect of approximately 2 °C. To maintain the skin temperature of 34°C, the additional cooling energy required would be reduced by 36 W m−2. These findings are expected to provide crucial guidance and predictions for the development of passive radiative cooling fabrics. [ABSTRACT FROM AUTHOR]

Temperature‐sensitive hydrogels have been widely used for rapid adaptive cooling in electronic device thermal management with promising applications. However, existing temperature‐sensitive hydrogels can only regulate the flow in the chip cooling system after the ambient temperature reaches their lower critical solution temperature (LCST). Before reaching LCST, effective rapid heat dissipation for electronic chips is not achievable. This study aims to develop a temperature‐sensitive hydrogel that can provide assisted adaptive cooling for electronic chips before reaching its LCST. This requires the hydrogel to have a thermal conductivity far surpassing existing hydrogel materials. Using the temperature‐sensitive hydrogel PNIPAm and graphene molecules as base materials, this research utilized molecular dynamics simulations to graft graphene molecules onto PNIPAm molecules in different ways, resulting in the temperature‐sensitive hydrogel material PNIPAm‐g‐graphene. Non‐equilibrium molecular dynamics (NEMD) was employed to calculate the thermal conductivity of this material under different temperature conditions. The results indicate that the thermal conductivity of PNIPAm‐g‐graphene can reach up to 1.95474 W/m K (graphene grafted at CH3 functional group, temperature at 280 K). Compared to the thermal conductivity of PNIPAm under the same conditions (0.45 W/m K), the increase in thermal conductivity is significant, demonstrating excellent thermal conductivity compared to PNIPAm. Subsequently, this study analyzed the underlying mechanisms of different thermal conductivities in materials obtained by grafting graphene molecules at different points using the method of overlap in Phonon Density of States Curves (PDOS) from the perspective of interfacial thermal conduction. Finally, through computational fluid dynamics (CFD) simulations, this study investigates the chip's adaptive cooling performance with PNIPAm‐g‐graphene material. The results show that, compared to traditional temperature‐sensitive hydrogels, PNIPAm‐g‐graphene can achieve efficient adaptive cooling of chip hotspots before the cooling fluid temperature reaches its LCST value. This finding is significant for the field of chip cooling. The study proposes a new method for rapid, adaptive cooling of chip hotspots and explores its feasibility from the perspectives of molecular dynamics and CFD simulation. It holds importance in the thermal management of electronic devices and the rapid adaptive cooling of electronic chips. [ABSTRACT FROM AUTHOR]

Radiative cooling, taking advantage of the coldness of the sky, has a potential to be a sustainable alternative to meet cooling needs. The performance of a radiative cooling device is fundamentally limited by the emissivity of the sky, therefore depends heavily on the regional weather conditions. Although the sky emissivity is known to increase with the dew point temperature, the feasibility of radiative cooling remains elusive in the equatorial tropical climate, where the weather is humid, cloudy, and constantly changing. It is pointed out that a high degree of thermal insulation of the radiative cooling system can be effective under such extreme weather conditions. A new method to characterize dynamic sky conditions is presented, namely to measure the sky window emissivity in the zenith direction. It is shown that a sub‐ambient cooling up to 8 °C is possible during daytime and that the cloud base is not a complete blackbody and can be used as a heat sink for radiative cooling. [ABSTRACT FROM AUTHOR]

A field campaign in a valley near Seefeld, Austria, well known for the frequent occurrence of cold‐air pools, was conducted to identify the processes leading to the formation and erosion of the cold‐air pool. Here, we focus on a case study in January 2020 that featured cold‐air pool formation interrupted by a wind disturbance. Simulations with the Weather Research and Forecasting model were performed at a horizontal grid spacing of 40 m and compared with measurement results. The model was able to reproduce the intense cooling in the beginning of the night and the cold‐air pool erosion in the middle of the night caused by the wind disturbance, but stronger winds than observed prevented the cold‐air pool from fully re‐establishing in the model after the disturbance. The dominant cooling processes were long‐wave radiative heat loss and turbulent exchange, both of which are parametrized and cool the air locally. Advection was the most important warming contribution during the cold‐air pool disturbances, especially its cross‐valley and vertical components. Owing to numerical constraints and the shallow nature of the cold‐air pool, its extent was limited to the lowest model level. Further improvements to the cold‐air pool's representation in the model would require a finer grid resolution. [ABSTRACT FROM AUTHOR]

Residual strength tests are commonly used to characterize the high‐temperature mechanical properties of concrete materials. In these tests, the specimens are heated to a target temperature in a furnace and then cooled down to room temperature, followed by mechanical testing at room temperature. This research investigates the influence of the cooling method on the residual strength of Strain Hardening Cementitious Composites (SHCC) after exposure to 400°C and 600°C. Two types of cooling methods — furnace‐cooling (within a closed furnace) and water‐cooling (immersed in a water tank) — were adopted. Four different SHCC previously investigated by the authors for high‐temperature residual mechanical and bond behavior with steel were studied. Two different specimen sizes were tested under uniaxial compression and flexure to characterize the residual compressive strength and modulus of rupture. The effect of the cooling method was prominent for the normalized residual modulus of rupture at 400°C, but not at 600°C. The cooling method had no effect on the normalized residual compressive strength of any material at either of the two temperatures, except one of the SHCC (PVA‐SC) at 400°C. Specimen size also had no effect on the normalized residual compressive strength and modulus of rupture irrespective of the cooling method. [ABSTRACT FROM AUTHOR]

Finding a real thermoelectric (TE) material that excels in various aspects of TE performance, mechanical properties, TE power generation, and cooling is challenging for its commercialization. Herein, we report a novel multifunctional Ge0.78Cd0.06Pb0.1Sb0.06Te material with excellent TE performance and mechanical strength, which is utilized to construct candidate TE power generation and cooling devices near room temperature. Specifically, the effectiveness of band convergence, combined with optimized carrier concentration and electronic quality factor, distinctly boosts the Seebeck coefficient, thus greatly improving the power factor. Advanced electron microscopy observation indicates that complex multi‐scale hierarchical structures and strain field distributions lead to ultra‐low lattice thermal conductivity, and also effectively enhance mechanical properties. High ZT ~ 0.6 at 303 K, average ZTave ~ 1.18 from 303 to 553 K, and Vickers hardness of ~200 Hv in Ge0.78Cd0.06Pb0.1Sb0.06Te are obtained synchronously. Particularly, a 7‐pair TE cooling device with a maximum ΔT of ~45.9 K at Th = 328 K, and a conversion efficiency of ~5.2% at Th = 553 K achieving in a single‐leg device. The present findings demonstrate a unique approach to developing superior multifunctional GeTe‐based alloys, opening up a promising avenue for commercial applications. [ABSTRACT FROM AUTHOR]

Passive daytime radiative cooling technology presents a sustainable solution for combating global warming and accompanying extreme weather, with great potential for diverse applications. The key characteristics of this cooling technology are the ability to reflect most sunlight and radiate heat through the atmospheric transparency window. However, the required high solar reflectance is easily affected by environmental aging, rendering the cooling ineffective. In recent years, significant advancements have been made in understanding the failure mechanisms, design strategies, and manufacturing technologies of daytime radiative cooling. Herein, a critical review on anti‐environmental aging passive daytime radiative cooling with the goal of advancing their commercial applications is presented. It is first introduced the optical mechanisms and optimization principles of radiative cooling, which serve as a basis for further endowing environmental durability. Then the environmental aging conditions of passive daytime radiative cooling, mainly focusing on UV exposure, thermal aging, surface contamination and chemical corrosion are discussed. Furthermore, the developments of anti‐environmental aging passive daytime radiative cooling materials, including design strategies, fabrication techniques, structures, and performances, are reviewed and classified for the first time. Last but not the least, the remaining open challenges and the insights are presented for the further promotion of the commercialization progress. [ABSTRACT FROM AUTHOR]

This article presents an experimental study of heat pipes supported by phase‐change materials (PCMs) coated at their adiabatic sections in application for electronics cooling. The PCMs investigated in this research are palmitic acid and beeswax, the latter being considered as a more cost‐effective alternative. The study focuses on three powers: 20, 25, and 30 W. The experimental results reveal that the incorporation of palmitic acid as a PCM leads to a reduction in component's maximum temperature by 13.3%, 12.6%, and 11.8% for the respective powers. Utilization of beeswax results in temperature reductions of 5%, 5.2%, and 8.4%. Notably, for higher heat flux conditions, the influence of beeswax on temperature control is comparable to that of palmitic acid. Furthermore, beeswax demonstrates a significantly higher capability to mitigate temperature decrease during cooldown, serving as a superior measure against overcooling. Moreover, during the thermal cycling scenario considered in this study, beeswax reduces the peak‐valley temperature by 25%, while palmitic acid achieves a reduction of 14.6%. These findings suggest that beeswax has the potential to serve as an alternative to traditional organic PCMs in electronics cooling applications that utilize heat pipes. [ABSTRACT FROM AUTHOR]

Passive radiative cooling without energy consumption is increasingly being explored as an eco‐friendly alternative to electric cooling for mitigating heat stress caused by global warming. Incorporating radiative cooling into personal thermal management has garnered widespread interest. However, existing sub‐ambient radiative cooling textiles face challenges related to inferior solar reflectance, poor outdoor durability, or health concerns. Here, a durable multilayer silk textile (MST) is developed that achieves excellent comprehensive performance for the first time, including both ultrahigh solar reflectance (96.5%) and ultrahigh infrared emittance (97.1%), safety, air and moisture permeability, high mechanical strength, washability, abrasion resistance, surface hydrophobicity, and UV resistance. The MST achieves a remarkable sub‐ambient temperature drop of 5.1 °C under 892.4 W m−2 of ultra‐strong solar radiation and surpasses both commercial silk and cotton textiles at noon with temperature reductions of 6.0 and 8.3 °C, respectively. For proof of concept, a hat using the MST is fabricated, which shows improved cooling performance compared to commercial hats. Considering its outstanding cooling performance, durability, zero energy consumption, abundant raw materials, and scalable production ability, it is believed that the radiative cooling MST holds great promise for practical applications in daytime personal thermal management. [ABSTRACT FROM AUTHOR]

As the body's largest organ, the skin is an integrated multisensory system with self‐healing ability and helps stabilize body temperature. It is herein, inspired by natural skin, a wearable patch made from porous polydimethylsiloxane (PDMS) skeleton, poly(vinyl alcohol) (PVA) hydrogel, and silicon oxide (SiO2) particles, offers a combination of self‐healing properties, along with hybrid radiative and evaporative cooling mechanisms, designed for electromyographic (EMG) signal detection and human‐machine interaction. The patch has both high mid‐infrared (MIR) emittance (96%) and visible to near‐infrared (visNIR) reflectance (80%), coupled with efficient water evaporation from the PVA hydrogel, resulting in a hybrid cooling power of 180 W m−2. It obtains a temperature drop of ≈7.7 °C using this patch under a solar intensity of ≈700 W m−2. Furthermore, the patch demonstrates self‐healing ability with ultrafast recovery of electrical conductivity (1 s) and a self‐healing efficiency (≈71%) of fracture strain. Thus, the wearable patch can detect high‐quality EMG signals and provide cooling effects and self‐healing capabilities that enhance comfortability and durability. These features make the patch an advanced solution for developing next‐generation wearable patches that can meet the rigorous demands of durable body temperature control in various applications. [ABSTRACT FROM AUTHOR]

Pathway‐dependent self‐assembly, in which a single building block forms two or more types of self‐assembled nanostructures, is an important topic due to its mimic to the complexity in biology and manipulation of diverse supramolecular materials. Here, we report a pathway‐dependent self‐assembly using chiral glutamide derivatives (L or D‐PAG), which form chiral nanotwist and nanotube through a cooperative slow cooling and an isodesmic fast cooling process, respectively. Furthermore, pathway‐dependent self‐assembly can be harnessed to control over the supramolecular co‐assembly of PAG with a luminophore β‐DCS or a photopolymerizable PCDA. Fast cooling leads to the co‐assembled PAG/β‐DCS nanotube exhibiting green circularly polarized luminescence (CPL), while slow cooling to nanofiber with blue CPL. Additionally, fast cooling process promotes the photopolymerization of PCDA into a red chiral polymer, whereas slow cooling inhibits the polymerization. This work not only demonstrates the pathway‐dependent control over structural characteristics but also highlights the diverse functions emerged from the different assemblies. [ABSTRACT FROM AUTHOR]

The purpose of this paper was to systematically review the literature and perform a meta‐analysis of the existing data on the effects of postexercise cold water immersion (CWI) coupled with resistance training (RT) on gains in measures of muscle growth. To locate relevant studies, we comprehensively searched the PubMed/MEDLINE, Scopus, and Web of Science databases. A total of 8 studies met the inclusion criteria; all investigated CWI as the means of cold application. Preliminary analyses conducted on noncontrolled effect sizes provided strong evidence of hypertrophic adaptations with RT that were likely to be at least small in magnitude (SMD0.5 = 0.36 [95% CrI: 0.10–0.61]; p (>0) = 0.995, p (>0.1) = 0.977). In contrast, noncontrolled effect sizes provided some evidence of hypertrophic adaptations with CWI + RT that were likely to be small to negligible in magnitude (SMD0.5 = 0.14 [95% CrI: −0.08–0.36]; p (>0) = 0.906, p (>0.1) = 0.68). The primary analysis conducted on comparative effect sizes provided some evidence of greater relative hypertrophic adaptations with RT compared to CWI + RT (cSMD0.5 = −0.22 [95% CrI: −0.47 to 0.04]) with differences likely to be greater than zero (p (<0) = 0.957) and of at least a small magnitude of effect (p (<−0.1) = 0.834). Meta‐regression did not indicate a potential moderation effect of training status (βTrained:Untrained0.5 ${\beta }_{\text{Trained}:{\text{Untrained}}_{0.5}}$ = −0.10 [95% CrI: −0.65 to 0.43] p < 0) = 0.653). In conclusion, based on the current data, the application of CWI immediately following bouts of RT may attenuate hypertrophic changes. Given the overall relatively fair to poor quality of the studies examined, the results of the current study should be interpreted with some caution. Highlights: Application of CWI immediately following bouts of RT may attenuate muscle hypertrophy in both trained and untrained individuals.The quality of evidence comparing RT versus CWI + RT is generally fair to poor, indicating a need for higher quality studies on the topic to draw stronger inferences. [ABSTRACT FROM AUTHOR]

Circumstellar disk (CD) around the first generation of stars have been numerically investigated here to see if the cooling regimes also play a role in the formation and evolution of the disk associated with the most massive protostars (MMPS). Also, an emphasis is given to exploring the effect of the initial turbulent motion of the metal‐free gas on the resulting morphology of the CD. For this, a systematic range of Mach number ℳ=0.1−1.0$$ \mathcal{M}=0.1-1.0 $$ has been examined. It has been found that the disk‐to‐star mass ratio Mdisk$$ {M}_{\mathrm{disk}} $$/Mstar$$ {M}_{\mathrm{star}} $$ is larger when the model evolution is based on the first H 2$$ {}_2 $$ line cooling followed by subsequent cooling via collision‐induced emission than in the model where only H 2$$ {}_2 $$ line cooling remains operative. Also, irrespective of the initial turbulence in the cloud, the former type of model yields a CD as massive as 7.66 M ⊙$$ {}_{\odot } $$ while the latter type produces a disk as massive as 1.29 M ⊙$$ {}_{\odot } $$. Moreover, the inner part of the CD is found dominated by higher subsonic turbulent motions in the case of the former type of models than in the latter type. CDs around MMPS in both types of models show stable disk structures. [ABSTRACT FROM AUTHOR]

"Flip‐flop" detachment mode represents an endmember type of lithosphere‐scale faulting observed at almost amagmatic sections of ultraslow‐spreading mid‐ocean ridges. Recent numerical experiments using an imposed steady temperature structure show that an axial temperature maximum is essential to trigger flip‐flop faults by focusing flexural strain in the footwall of the active fault. However, ridge segments without significant melt budget are more likely to be in a transient thermal state controlled, at least partly, by the faulting dynamics themselves. Therefore, we investigate which processes control the thermal structure of the lithosphere and how feedbacks with the deformation mechanisms can explain observed faulting patterns. We present results of 2‐D thermo‐mechanical numerical modeling including serpentinization reactions and dynamic grain size evolution. The model features a novel form of parametrized hydrothermal cooling along fault zones as well as the thermal and rheological effects of periodic sill intrusions. We find that the interplay of hydrothermal fault zone cooling and periodic sill intrusions in the footwall facilitates the flip‐flop detachment mode. Hydrothermal cooling of the fault zone pushes the temperature maximum into the footwall, while intrusions near the temperature maximum further weaken the rock and promote the formation of new faults with opposite polarity. Our model allows us to put constraints on the magnitude of two processes, and we obtain most reasonable melt budgets and hydrothermal heat fluxes if both are considered. Furthermore, we frequently observe two other faulting modes in our experiments complementing flip‐flop faulting to yield a potentially more robust alternative interpretation for existing observations. Plain Language Summary: At mid‐ocean ridges, two plates diverge and new seafloor is created. The nature and appearance of this new seafloor strongly depend on spreading velocity and the availability of magmatic melts. At one of the melt‐poorest and slowest‐spreading ridges, a special form of large‐scale tectonic faults, so‐called flip‐flop detachments, can be observed. Tectonic faults can act as pathways for fluids circulating through the seafloor, which provides a significant cooling effect for the young plate. The interplay of magmatic activity, faulting and fluid circulation is evident at many different ridges with different magmatic activity and spreading rates. Flip‐flop faulting is restricted to only a few ridge sections worldwide, and we here investigate the prerequisites for this special spreading mode. To do so, we set up a computer model of an ultraslow‐spreading mid‐ocean ridge including the effects of sparse magmatism as well as the cooling effect associated with fluid circulation. We find that feedbacks between faulting dynamics, hydrothermal cooling and magmatic activity control the magnitude and spatial location of each individual process. Seafloor and subsurface observations are best explained by calculations with moderate melt input and hydrothermal circulation acting together. Key Points: We implemented hydrothermal cooling and magmatic intrusion in a thermo‐mechanical model to explain detachment faulting at ultraslow ridgesStable flip‐flop detachment faulting is observed for setups considering both melt input and hydrothermal heat fluxes at realistic magnitudesTwo other faulting modes frequently observed in our model offer potential alternative interpretations for existing seafloor observations [ABSTRACT FROM AUTHOR]

Building cooling loads, which continue to increase with increasing global temperatures, are responsible for large quantities of greenhouse gas emissions. Radiative cooling (RC), whereby structures are cooled by emitting radiation in the atmospheric window, from 8–13 μm, to outer space, is a promising clean technology that can be used to meet ever‐increasing building cooling demands. However, the effects of using RC on the airflow velocity and temperature distributions within the occupied zone of buildings are yet to be investigated. Herein, computational fluid dynamics simulations are performed to study the transient airflow velocity and temperature distributions in buildings that are cooled using RC material on their rooftops. For idealized conditions when the thermal mass of the house is neglected, the results show that when the cooling power provided by the RC material is qc″=−50Wm2 $q_{\text{c}}^{''} = - 50 \frac{W}{m^{2}}$ , and qc″=−100Wm2 $q_{\text{c}}^{''} = - 100 \frac{W}{m^{2}}$ the average temperature of the occupied zone in the building is reduced from 295 K to about 293 and 289.7 K after two minutes, respectively. These rapid cooling rates were attained without exceeding head‐to‐ankle temperature differences of about 2.7 °C and with air flow velocities maintained below 19.0 cm s−1, which is consistent with a comfortable environment. [ABSTRACT FROM AUTHOR]

In recent years, an increasing number of passive radiative cooling materials are proposed in the literature, with several examples relying on the use of silica (SiO2) due to its unique stability, non‐toxicity, and availability. Nonetheless, due to its bulk phonon‐polariton band, SiO2 presents a marked reflection peak within the atmospheric transparency window (8‐13 µm), leading to an emissivity decrease that poses a challenge to fulfilling the criteria for sub‐ambient passive radiative cooling. Thus, the latest developments in this field are devoted to the design of engineered SiO2 photonic structures, to increase the cooling potential of bulk SiO2 radiative coolers. This review seeks to identify the most effective photonic design and fabrication strategies for SiO2 radiative emitters by evaluating their cooling efficacy, as well as their scalability, providing an in‐depth analysis of the fundamental principles, structural models, and results (both numerical and experimental) of various types of SiO2 radiative coolers. [ABSTRACT FROM AUTHOR]

Two new pentagon‐embedded carbo[11]helicenes have been designed and synthesized in a three‐step process, which are the first example of carbo[11]helicenes through the post‐functionalization of twistacene. TD‐DFT analyses indicate that both of them possess high enantiomerization barriers of 42.29 kcal/mol and 40.76 kcal/mol, respectively. They emit strong red fluorescence and can be chemically oxidized into stable cationic radicals upon addition of AgSbF6 evidenced by the bathochromic‐shifted absorption spectra and the appearance of electronic paramagnetic resonance (EPR) signals. In addition, such helical derivatives can be chosen as radiative cooling materials in a glass model house, and the maxima of 5.4 °C for the former and 6.5 °C for the latter are found in the comparative tests, which might be caused by the NIR reflective response. [ABSTRACT FROM AUTHOR]

With the great increase in installation, photovoltaics will develop as the main power supply source for the world shortly. However, the actual power generation and lifetime of photovoltaics are greatly compromised by the high working temperature under outdoor operation. In this review, the recent advances of four promising passive photovoltaic cooling methods are summarized with the aim to uncover their working principles, cooling performance, and application potential in photovoltaic devices. For radiative cooling, light management strategies with ultraviolet‐photon downshift and sub‐bandgap reflection are discussed in detail to reveal their great potential in reducing photovoltaic working temperature and enhancing power generation. Subsequently, the great cooling benefits of passive evaporative cooling are underlined in terms of its superior cooling power and temperature drop of photovoltaic devices. Moreover, the promising integrated cooling strategy is further highlighted due to its great potential in enhancing electricity production and fresh water supply. Most crucially, the remaining challenges and the authors'r insights are presented to advance the commercial applications of passive cooling methods in photovoltaics. [ABSTRACT FROM AUTHOR]

Plastic 3D printing allows the replacement of metal parts in a water/silica gel adsorption heat transformer module and its rapid manufacturing at low cost. This research investigates a simple design using three finned metal heat exchangers (HEXs) enclosed in one plastic 3D‐printed vessel. The dynamics of a conventional packed bed adsorber of Siogel silica gel grains with thermal response method is first identified to establish a benchmark case and allow to focus only on the challenges introduced by plastic 3D printing. Final testing of the device across a range of operating conditions and cycle times representative of cooling, desalination, and intermediate shows the adsorber follows an unconventional thermodynamic cycle. Generation of larger powers is achievable by coupling multiple small modules. [ABSTRACT FROM AUTHOR]

Barium sulfate (BaSO4) has high reflectance throughout entire solar waveband (280–2500 nm). In this study, the melt blending method was used to incorporate BaSO4 into a plasticized polyvinyl chloride (PVC) matrix. The aim was to create composites that exhibit excellent reflective cooling performance in the solar waveband, specifically for use in building roofs. By increasing the content of BaSO4 from 0 to 200 phr, the total reflectance of the samples in the solar waveband showed significant improvement, rising from 6% to 48.8%. Furthermore, the thermal conductivity of the samples accordingly emerged apparent enhancement, increasing by 46.3% from 0.178 to 0.262 W m−1 K−1. Additionally, when subjected to irradiation by a solar simulator under a solar light intensity of 1000 W/m2 for 1 h, the indoor simulated irradiation temperature decreased from 41.4 to 27.4°C. Highlights: White plasticized polyvinyl chloride (PVC) films with reflective cooling performance were prepared.The solar reflectance and cooling performance of PVC was enhanced by BaSO4.The reflectance mechanism of BaSO4 in PVC was established. [ABSTRACT FROM AUTHOR]