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Lithium metal anodes suffer from low Coulombic efficiency and dendritic growth owing to an unstable solid electrolyte interphase (SEI), which limit the practical applications of lithium metal anodes. Here, zincone (ZnHQ) is conformally fabricated on 3D copper nanowires (CuNWs) via a molecular layer deposition (MLD) technology. Upon polarization, the terminal oxygen of ZnHQ serves as a strong nucleophilic agent to attack Li bis(trifluoromethanesulfonyl)imide, yielding a LiF‐rich SEI. This SEI facilitates the Li transport, shuts off the electron conduction, and inhibits the growth of lithium dendrites. In addition, the zinc atoms of ZnHQ induce favorable Li deposition owing to their lithiophilicity. These advantages enabled by MLD make the ZnHQ‐modified CuNW (CuNW@ZnHQ) an ideal Li metal anode, which demonstrates excellent cyclability. A symmetrical cell of CuNW@ZnHQ shows high cycling stability for more than 7000 h at the current density of 1 mA cm−2. When pairing with a Ni/Co/Mn ternary oxide cathode (NCM523), the resultant CuNW@ZnHQ||NCM full cell is cycled for 1000 cycles with a 90% capacity retention at an areal capacity of 3.2 mAh cm−2. The MLD technology brings new opportunities for next‐generation high‐energy Li metal batteries. [ABSTRACT FROM AUTHOR]

The receiver serves as a critical component in tower-type concentrated solar power plants. Responsible for light-heat conversion, the efficiency of the receiver significantly affects the overall performance of the power plant. In the current study, the thermal performance of external receivers was investigated. An experiment was set up similarly using the solar simulator to experimentally investigate the heat losses of a billboard receiver. A billboard-type external receiver was designed, fabricated, and experimented with. A solar simulator having seven xenon lamps characteristics similar to the sunlight spectrum was used to obtain heat flux at the surface of the receiver. Convection losses in the head-on wind direction were evaluated, along with the radiation losses. The thermal efficiency of the billboard receiver calculated experimentally was around 83.9%. Numerical simulations were also carried out to compare the results against the experimental data. A variation of ±5% observed between both results validate the model proposed in the current study. [ABSTRACT FROM AUTHOR]

[Display omitted] • A Nb-based hybrid coating for Si anodes was synthesized by MLD and annealing. • The coating provides enhanced tolerance of stress and resistance to side reactions. • A thin, stable LiF-rich SEI layer is established on the Si anode. • Fast Li+ transport kinetics and low stress distribution in the SEI is confirmed. • The Si anode exhibits advantageous rate capability and capacity retention. Silicon material anodes are attractive for a range of high energy density lithium-ion battery applications, but their huge volume expansion, interfacial side reactions, and fast capacity decay are limitations. Herein, molecular layer deposition (MLD) is used to deposit a Nb-based inorganic-organic coating onto casted silicon nanowire (Si NW) electrodes, forming an artificial solid-electrolyte interphase (SEI). Post annealing of the coated composite (Si NW@NbHQ-500) drives a general cross-linking reaction within (-Nb-O-benzene-O-) n units, achieving enhanced mechanical and chemical robustness of the interface. The coating material and its reduced products (Nb4+ species) appear to be involved in a thin and LiF-rich SEI framework, accelerating interfacial Li+ diffusion. With mechanical strain dissipation and natural SEI erosion suppression, the anode exhibits an advantageous rate capability of 940 mAh/g at 4 A/g, a high reversible areal capacity of 4.0 mAh cm−2, an impressive capacity retention with a capacity decay of only ≈0.06 % per cycle over 800 cycles at 1 A/g, as well as a stable full cell electrochemical cycling performance when integrated with a LiFePO 4 cathode. Additionally, SEI modulus test verifies that the Si NW@NbHQ-500 anode undergoes gentle reversible interfacial evolution during cycling with a slight average modulus rise (≈10.3 to 37.9 GPa) from surface to bulk. This work demonstrates the great potential of Nb-based inorganic-organic hybrid nano coatings for mechanical and electrochemical stabilization of silicon anodes. [ABSTRACT FROM AUTHOR]

A simulation method consisting of Monte Carlo Ray-Trace and Finite volume coupled model is proposed in the present work for simulation of complex photo-thermal conversion in the particle entrapped cavity receiver. The solar heat flux distribution in the cavity receiver was simulated by using the Monte Carlo ray tracing, while the convection-radiation-conduction process taking place in the cavity receiver was simulated by the Finite Volume Method. Solar heat flux was introduced as a source term in the energy equation for the Finite Volume Method part, and correlations for flow boiling heat transfer were chosen to calculate the surface temperature of the boiling tubes. Based on the simulation model, the thermal performance of the receiver, the temperature distribution and the mean square deviation of temperature at the outer surface of the boiling tubes were analyzed at varying albedo ω , diameter D and time (8:00–16:00). It was revealed that the temperature distribution on the outer surface of the boiling tubes can be uniformed by entrapping carbon particle sin the receiver. The results indicate that the collision between photon and carbon particles resulted in scattering and absorbing, with a tendency to decrease the maximum heat flux and temperature gradient at the surface of tubes. Although the thermal efficiency of the receiver decreases by 4.5%, the maximum temperature was reduced from 665 K to 630 K and the mean square deviation of temperature on the outer surface of backpanel was reduced from about 43 K to 26 K at noon. The results are useful for choosing suitable parameters for entrapped particles in cavity receivers to improve efficiency and operational safety. • MCRT and FVM methods were applied to evaluate the thermal efficiency of a cavity receiver. • Thermal efficiency of the cavity receiver at varying sun positions along the passage of day was evaluated. • Effects of particle's radiation properties on thermal performance of the receiver were investigated. • Carbon aerosol was used to achieve uniform heat flux distribution and overcome the localized heating problem. [ABSTRACT FROM AUTHOR]

An uneven heat flux distribution on the receiver's surface can lead to a highly non-uniform temperature distribution and high local temperature on the receiver tubes which results in fatigue failure. In the present work, a carbon aerosol entrapped cavity receiver of "DAHAN" power plant was numerically simulated to achieve homogenized heat flux distribution with improved safety of the receiver. A three-dimensional Monte Carlo Ray Tracing (MCRT) and Finite Volume Method (FVM) coupled model was developed to simulate the radiation-conduction-convection heat transfer in the receiver. Firstly, the MCRT method is used to simulate the solar heat flux distribution on the surface of the receiver. Then, the thermal performance and heat losses in the receiver were investigated by the coupled model. Finally, the levelized cost of energy (LCOE) was calculated and stress analysis was performed to predict the lifespan of the receiver. Moreover, with this strategy, the peak solar heat flux on the back panel significantly dropped from 290 kW/m2 to 135 kW/m2, while the peak temperature dropped from 652K to 620K. Carbon aerosol particle slightly decreases the thermal performance of the receiver. However, it decreases stress concentration on the receiver panels. Also, the economic analysis revealed that carbon aerosol entrapped receiver is more economical. • Thermal performance of carbon aerosol entrapped receiver is evaluated through a 3D MCRT-FVM coupling model. • Effects of the varying carbon aerosol density on heat flux and temperature distribution on the tube surfaces are examined. • Effect of varying carbon aerosol density on the thermal performance and heat losses of the cavity receiver is evaluated. • Economic and stress analyses of the receiver are performed with varying carbon aerosol density. [ABSTRACT FROM AUTHOR]

Highlights • Thermal performance of an external receiver is numerically evaluated. • Different wind directions and wind velocities are experimented to evaluate the losses. • A novel design using wind blocking walls is tested to successfully reduce the losses. • Receiver and wind characteristics dependent correlation is derived to evaluate losses. Abstract The efficiency of a CSP plant heavily depends on the performance of the receiver. The receiver is responsible for light-heat conversion in a power generation system. With the objective of numerical evaluation of the thermal losses of an external receiver, a method was developed in the present study. Solar flux was obtained on a north-facing receiver using the "SolarPilot" software, through Monte-Carlo ray tracing technique. Apposite boiling heat transfer coefficients were selected and then applied to obtain the temperature at the surface of the boiling tubes. Numerical simulations were performed to quantify the heat losses in the receiver at different wind velocities. Maximum heat flux and temperature were obtained at the center of the receiver. The results indicated that wind direction and wind velocity have a significant impact on the extent of heat losses. Maximum heat losses occur in the side-on wind direction (i.e., west bound) while losses are minimum in the head-on wind direction (i.e., north bound). Thermal losses through the receiver contribute a sizeable portion to overall energy losses in power tower systems, hence, to attenuate the heat losses a new, yet simple, design is proposed with the addition of wind-blocking walls at the receiver's periphery. The walls achieve noticeable heat retention in all wind directions, but their role is more prominent in the head-on wind direction. In best case scenario, attaching 1 m wide wind blocking walls resulted in a diminution of about 33 percent of losses in the head-on wind direction at 9 m/s wind velocity. Results obtained are then employed to derive a simplified correlation model to evaluate convective heat losses as a function of wind direction, wind velocity, receiver's surface area and wind blocking wall width. [ABSTRACT FROM AUTHOR]

Highlights • An integrated method based on a two-band semi-gray surface approximation is employed. • The solar absorptivity is a critical parameter relative to other surface properties. • The receiver efficiency shows different variations with the thermal emissivity. • The infrared heat transfer direction between passive and active surfaces is crucial. • The passive surfaces should be highly reflective due to the great cavity effect. Abstract Solar cavity receiver is one of the most crucial components in a solar power tower system, where the solar-thermal conversion process is achieved. Optimizing the surface properties (viz. absorptivity and emissivity) of a designed cavity receiver is a viable option to improve its thermal efficiency. In the present paper, an integrated simulation approach was employed to quantify the influence of surface optical and radiative properties on the thermal performance of a typical water/steam solar cavity receiver. Firstly, the different candidate surface materials, solar selective and non-coated, were compared. The results showed that the thermal efficiency of the receiver with the ideal coating and Pyromark 2500 is respectively enhanced by 12.5% and 7.8% compared with that of the non-coated receiver. And then, the effects of surface spectral selectivity on the thermal performance of the receiver were carefully analyzed. It can be found that the solar absorptivity is the most critical parameter for improving the receiver efficiency, which is enhanced by about 12.6% as the solar absorptivity rises from 0.8 to 1.0. However, the receiver efficiency shows different variation tendencies with the thermal emissivity of active surfaces, which are closely related to the infrared heat transfer direction between the passive surfaces and the active surfaces. Furthermore, with the increase of reflectivity of passive surfaces over the full spectrum, the receiver efficiency is determined by a trade-off between the increasing reflective heat loss and the decreasing radiative and convective heat losses. For the present receiver, the thermal efficiency is improved by about 4.8% with the reflectivity increasing from 0 to 1.0 due to its great cavity effect. Therefore, the passive surfaces should be highly reflective throughout the spectrum inside the present receiver. [ABSTRACT FROM AUTHOR]

The high temperature receivers in CSP plants should startup frequently, so the thermal stress and the fatigue failure are critical important for its safety and stability. In our present study, a computation model is proposed for a water/steam cavity receiver in CSP plant. The model couples the light propagation, the light-heat conversion, the thermo-elasticity and the thermal fatigue analysis together. Monte Carlo ray tracing method (MCRT), finite volume method (FVM) and boiling heat transfer are coupled to get the thermal boundary of the boiling panel. Finite element method (FEM) is adopted to obtain the temperature and stress–strain distribution of the boiling panel. Elastic stress analysis and equivalent stress fatigue assessment method is used to investigate the fatigue failure of the boiling panel. Two different structures of the boiling panel are researched, following results are obtained: The heat flux on the boiling panel is highly non-uniform and it results in the similar non-uniform distributions of temperature and stress-strain as well as the displacement of the boiling panel. The non-uniform stress-strain leads to the warping of the boiling panel and the largest displacement is in the direction normal to the heat absorbing surface toward the cavity internal, the largest displacement range is 17 cm. Fins of the boiling panel at the elbow region (case-1 in the present study) can lead to hot spots of which the temperature is extremely higher than that of boiling tubes, cutting off the fins at the elbow region (case-2 in the present study) can eliminate the hot spots and has no impact on temperature distribution of the boiling panel’s main part. The temperature difference on the cross section of the boiling tube is very high (about 130 °C while the heat flux is about 350 kW/m 2 ) both in radial and circumferential direction, and this high temperature difference results in the high thermal stress on the boiling panel and the maximum thermal stress occurs at the welding region. The welding quality has a significant impact on the fatigue failure of the boiling panel. For a receiver design life of 20 years, membrane wall with cutting off the fins at the elbow region (case-2 in the present study) is a good design and the welding quality level 3 should be ensured at least and only one cold startup for a day is permitted. [ABSTRACT FROM AUTHOR]

A non-uniform solar flux leads to a non-uniform temperature distribution on the walls of cavity receiver. There exists a large temperature gradient, which can cause great challenges for the safety and high-efficiency operation of concentrating solar power system (CSP). To overcome this problem, micron particles with strong properties of absorption, scatter and radiation are added into the cavity receiver to improve the non-uniform heat flux distribution on the wall. In the present research, a coupled simulation method based on Monte Carlo Ray Tracing (MCRT) method and Finite Volume Method (FVM) is established to simulate the complex photo-thermal conversion process of a two-dimension square solar cavity filled with air-carbon particle mixtures. In the model, first, the solar heat flux distribution on the surface of cavity receiver is simulated by MCRT and the photo-thermal conversion process in the receiver is modeled by FVM. Then both are coupled in the cavity receiver by transferring the absorbed solar energy computed by MCRT to FVM, and this energy is applied as a source term for the energy equation in the FVM part. Based on the coupling model, the thermal performance and the temperature distribution characteristics on the wall of the cavity receiver are studied at various particle densities. The results show that as carbon particle density increases, the heat flux and temperature distribution on the walls of the receiver becomes more uniform and the effects of different L / D and N on σ T of the receiver are further investigated. [ABSTRACT FROM AUTHOR]

In this study, core-shell structured silica-coated silicon carbide (SiC@SiO 2 ) whisker reinforced vitrified matrix composites with four distinct whisker concentrations were prepared by pressureless sintering. The effects of SiC@SiO 2 core-shell filler on the morphology, mechanical properties, open porosity, and Rockwell hardness of the sample were investigated. The mechanical behaviour and void structures were correlated with the microstructure evolution, including the whisker/matrix interaction. When the whisker added fractions were 4 wt% (SiC whisker) and 3 wt% (SiC@SiO 2 whisker), the flexural strength of the samples reached their maximum values of about 72.13 MPa and 71.60 MPa, respectively. Furthermore, the bending strength of the SiC@SiO 2 whisker (2 wt%) reinforced vitrified composites was 71.51 MPa, and the open porosity and hardness were 23.69% and 48.5 HRB, respectively; these values were higher than those for the composites with the SiC whiskers (2 wt%). This result can be attributed to the protective coating of the SiO 2 shell and the good wetting between the SiC@SiO 2 filler and the glass bond. [ABSTRACT FROM AUTHOR]

The application of conventional tin oxide thin film sensors is limited by its low response. In this study, a heterojunction thin film composed of nickel oxide deposited by electron beam evaporation and tin oxide prepared by radio-frequency (RF) magnetron sputtering has enhanced gaseous ethanol sensing properties. The 5 nm NiO/100 nm SnO 2 gas sensor shows the excellent response 7.9 at 250 °C for 100 ppm gaseous ethanol, good reproducibility, as well as good linearity. In addition, this sensor can measure the ultra-low concentration of gaseous ethanol, and the concentration can be as low as 100 ppb. The gas sensitive properties is related to the thickness of nickel oxide and the mechanism is discussed. [ABSTRACT FROM AUTHOR]

The geometry of a solar cavity receiver affects the absorption of incident solar energy and the temperature distribution on the absorber tube panels, and hence affects the operation stability and efficiency of the solar receiver. A modified combined computational method was proposed to investigate the thermal performance of the three dimensional (3-D) molten salt cavity models in steady state. This computational method was also used to calculate the thermal performance of the receiver in the Molten-Salt Subsystem/Component Test Experiment (MSS/CTE) in the United States, and the results agree well with published data. Molten salt cavity receivers with different heights were studied. The results show that a too-low or too-high height leads to low thermal efficiency of a receiver. Therefore, appropriate heights shall be chosen to enable receivers achieve relatively high efficiencies and reach low temperatures. The molten salt cavity receivers with different cross-sections in the chosen heights were then studied, to obtain a high-efficiency cavity receiver structure without increasing the inner surface area or the depth of the cavity, under the condition that the molten salt cavity receivers were in the same perimeter of the cross-section, aperture size, cavity height, tube panel and fluid flow layouts but different cavity depths. When only the lengths of the back walls next to the side walls had been increased, the thermal efficiency decreased first and then increased with the depth decreasing, which reached the lowest value when the depth was 2.71 m. When the depth of the modified receiver is small enough, its thermal efficiency can be higher than that of the MSEE receiver. When only the lengths of the two walls adjacent to the aperture had been increased, the thermal efficiency increased with the depth decreasing, and was always higher than that of the receiver in the Molten-salt Electric Experiment (MSEE) in the United States. The thermal-efficiency difference between the two arrangements of the side walls decreased with a decrease in the cavity depth. The cross-section of the MSEE receiver is similar to that of the receiver in the molten salt electric experiment by Sandia National Laboratories. Under the condition of side-on wind at a velocity of 8.3 m/s, the thermal efficiency of the modified cavity with the minimum depth is 2% higher than that of the MSEE cavity with the maximum depth. The convective heat loss is 3.1% lower, while the radiative and reflective heat losses changed slightly. Therefore, the modified cavity in the present study is capable of achieving a higher efficiency with a less depth. [ABSTRACT FROM AUTHOR]

This paper focuses on the influence of fly ash cenosphere (as a pore former) content and particle size on the porosity, microstructure and mechanical properties of vitrified bond diamond tools. The sintered specimens were examined using comprehensive thermal analysis, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, three point bending tests and porosity measurements. The porous morphological parameters (volume, size and distribution of pores) of the sample correlated with the content and size of the fly ash cenosphere, and diffusion layers were formed between the pore former and the vitrified matrix. The bending strength of the porous vitrified matrix varied between 27.28 and 35.92 MPa as the porosity changed from 40.66–43.97%. Based on response surface methodology (RSM) studies, two second-order response models for the open porosity and bending strength were established, and the utilization of the response surface model was evaluated with regards to the content and size of fly ash cenosphere present. [ABSTRACT FROM AUTHOR]

Background The mortality and morbidity rates in children with lower respiratory tract infection (LRTI) remain high. Objective To describe the number of bacteria that is associated with leukocytes in differential diagnosis of bacterial, mycoplasma, and viral LRTI in children. Methods Sputum smears were Gram stained for counting single-morphology bacteria associated with leukocytes. The differential diagnostic values of bacterial number were assessed in children with LRTI. Results The area under the receiver operating characteristic (ROC) curve was 0.95 for bacterial number in the differential diagnosis of bacterial infection from mycoplasma and viral infections. The area under the ROC curve was 0.62 for procalcitonin and 0.94 for bacterial number in the differential diagnosis of bacterial infection from mycoplasma infection. Conclusion The number of bacteria associated with leukocytes in sputum was valuable and rapid in differential diagnosis of bacterial infection in children with suspected bacterial, mycoplasma, and viral LRTI. [ABSTRACT FROM AUTHOR]

• Bed-to-tube heat transfer in fluidized bed with mixed-size particles are simulated. • Average HTC increases nonlinearly with the proportion of small-size component. • Local HTC is improved by enlarging the size difference between components. • A modified heat transfer correlation for complex particle systems is proposed. Mixed-size particles with low processing cost have great potential to act as the absorbing media in the next-generation concentrated solar power plants. However, the research on the heat transfer from the particles to heated surfaces in gas–solid fluidized beds is limited. In this paper, the bed-to-tube heat transfer coefficient (HTC) in a shallow fluidized bed with immersed tubes is determined numerically. The Eulerian–Eulerian approach that incorporated the kinetic theory of granular flow has been implemented in a two-dimensional model. The distribution of the local HTC around the tube is investigated for various particle systems. The results show that the HTC reaches a maximum at the upper right (45°) and upper left (135°) of the tube, respectively, indicating a strong relation between the local HTC and solid volume fraction (SVF). The average HTC increases as the mean particle size gets smaller. For monosized particles, the HTC increases from 925 W/(m2·K) to 3033 W/(m2·K) as the particle size decreases from 300 to 100 µm. For binary particles, the growth in the HTC is nonlinear, with an increase in growth rate being observed as the small-size component becomes dominant. For mixed-size particles with the same mean size, a higher HTC can be achieved by enlarging the size difference between the components. A modified correlation for predicting the bed-to-tube HTC is established. Besides, the impacts of gas velocity and temperature, and heat radiation on the bed-to-tube HTC are discussed. It is found that an optimal gas velocity exists to maximize the average HTC and SVF simultaneously, while the gas temperature has a minor contribution. Due to the small heat transfer temperature difference, the effect of thermal radiation on the HTC can be neglected even though the bed temperature reaches 800 °C. [ABSTRACT FROM AUTHOR]

• Supercritical CO 2 mixture Brayton cycle with floating critical points is proposed. • Energy consumptions of distillation based composition tuning systems are analyzed. • CO 2 -H 2 S cycle shows the most significant efficiency improvement. • Hourly efficiency of SBC-CTS is calculated based on typical daily temperatures. A novel concept of supercritical Brayton cycle with floating critical points is proposed to cope with the rapid deterioration of cycle performance at high heat sink temperatures. By coupling the power cycle with a distillation based composition tuning subsystem, the circulating mixture composition in the cycle can be altered dynamically to obtain the desired critical points at various ambient temperatures, thereby leading to a better match between the cold-end parameters of power cycle and the heat sink conditions. A thermodynamic model is established for the proposed novel system based on a recompression layout with single stage reheating. Four binary mixtures, including CO 2 –H 2 S, CO 2 –Butane, CO 2 –Isobutane, and CO 2 –Butene are employed. Simulation results indicate that an increasingly larger improvement in cycle efficiency compared to the pure CO 2 cycle can be obtained as the ambient temperature increases from 20 to 50 °C. When the composition tuning process is not considered, the CO 2 –H 2 S cycle shows the best performance among the four mixture cycles, with an improvement between 1.3% and 7.4% being achieved over the entire temperature range. Several feasible schemes for composition tuning subsystem are proposed and compared in terms of energy consumption. Finally, the hourly efficiencies of the integrated system are evaluated based on typical daily weather conditions, with a piecewise control strategy for critical points. It is found that although the use of CO 2 –H 2 S causes relatively high energy consumption for distillation, a significant improvement in the daily average thermal efficiency of the integrated system can still be achieved, with efficiency being increased by 3.5%-5.1% in comparison with pure CO 2 cycle on hotter days. [ABSTRACT FROM AUTHOR]

• Innovative design of concentrators with Multiple Reflections Elimination in Cross Compound Parabolic Concentrator. • Reduction in material consumption. • Enhanced solar flux uniformity. This paper evaluates low-profile solar concentrators with low-material consumption that improve the optical performance of Crossed-Compound-Parabolic-Concentrators (CCPCs) by using Eliminating-Multiple-Reflections (EMR). Three CCPC designs, LEMR, HEMR, and hybrid, were analysed using Monte-Carlo ray tracing, with optical efficiency and light flux uniformity as primary metrics. The LEMR and HEMR CCPCs achieved almost 88% average optical efficiency at the outlet aperture within the half acceptance angle. At the BCP, the LEMR CCPC attained an average efficiency of 85.7%, while the HEMR CCPC achieved an average efficiency of 85%. The hybrid CCPC achieved an average optical efficiency of 80% and 86% when the incidence angle was varied in the XY and YZ planes. The results showed that the non-uniformity of the light flux at the BCP remained low compared to the outlet aperture with changes in the incidence angle. A material consumption analysis revealed that the LEMR CCPC has the lowest material consumption as compared to the HMR and hybrid CCPCs and has a more uniform irradiance flux at the BCP. The LEMR CCPC has a relatively lower acceptance angle than the HEMR CCPC, making it suitable for a tracking system with a higher concentration ratio. The HEMR CCPC, on the other hand, can be used as a stationary concentrator due to its larger acceptance angle with a lower concentration ratio and can be applied in rooftops and building-integrated photovoltaics. Similarly, the hybrid CCPC has two different ranges of acceptance angles, making it advantageous for use in rooftops and building-integrated photovoltaics with seasonal tracking. [ABSTRACT FROM AUTHOR]

• Innovative combination of optical concentrator and solar steam generation module. • Better yield of the system with water flux of 3.5 kg∙m−2∙h−1 under outdoor conditions. • Economizing of installation area and a lower water production cost of 7.03 $/m3. Solar steam generation (SSG) for water treatment has attracted great interest for its convenience, accessibility and eco-friendliness. However, water production rate of traditional floating structure SSG system is relatively low. To further increase the water production rate, we develop a solar thermal-latent heat cascade utilization SSG system coupled with compound parabolic concentrator for desalination. A 2 × compound parabolic concentrator (CPC) was used in the outdoor experiment to improve the incident solar flux. Solar absorber of the SSG module has a high solar absorbance of 95 % which can effectively harvest solar energy and convert it into heat. A thin air gap above the solar absorber can restrain thermal loss through convection and radiation. Within the SSG module, seawater was supplied for the evaporation process driven by the capillary force in the capillary wick. Through the multi-stage design, solar thermal conversion and latent heat cascade recovery were achieved. As a result, the SSG module can achieve a gain to output ratio (GOR) of 185.09 % with a water flux of 2.82 kg∙m−2∙h−1 under one sun. Concentrating solar flux reached 1300 W∙m−2 in an early autumn day and a corresponding water flux of 3.5 kg∙m−2∙h−1 was achieved. Theoretical analysis showed that higher solar flux can increase the GOR. Optical concentration of 2 × can increase annual fresh water by 1.72 times while maintaining economic benefit. An insulation air gap above the solar absorber can reduce thermal loss from the solar absorber. Increasing stages can increase number of times the latent heat being reused and improve GOR, but economic benefit decreased with the increase of stage number. Considering the economic benefit and floor area, optical stage number of the system should be 4. Annual water production evaluation showed that a 1 m2 area system can annually generate 6321.29 kg fresh water with a water production cost of 7.03 $/m3. [ABSTRACT FROM AUTHOR]

The correct Table 1 is as below: Table 1 Clinical and intracranial plaque characteristics of study population and comparison between stroke and non-stroke patients. B Text Correction b In Abstract, the sentence "They were assigned to the posterior circulation stroke (49 patients) and non-posterior circulation stroke group (159 patients) based on clinical presentation and diffusion-weighted imaging (DWI)" should be replaced with "They were assigned to the posterior circulation stroke (59 patients) and non-posterior circulation stroke group (149 patients) based on clinical presentation and diffusion-weighted imaging (DWI)". A Predictive Model for the Risk of Posterior Circulation Stroke in Patients with Intracranial Atherosclerosis Based on High Resolution MRI. [Extracted from the article]

[Display omitted] • Microfluidic strategy for continuous and high-throughput synthesis of nanofluids. • Flexible preparation of boehmite nanofluids with controllable morphology and sizes. • Effect of morphology on heat transfer performance was systematically explored. • CHF and HTC of sphere nanofluids were increased by 24% and 14.4%, respectively. • Enhanced heat transfer mechanism was analyzed via bubble image processing. Enhanced boiling heat transfer through nanofluids represents a significant approach to improving the cooling performance of electronic devices. However, the preparation of nanofluids poses challenges regarding production efficiency, morphology control, and structural stability. In addition, the underlying mechanism of flow boiling heat transfer enhancement of nanofluids, particularly changes in vapor behavior, remains a limited understanding. This study presents a facile and straightforward microfluidic strategy for the controllable synthesis of nanofluids toward efficient heat transfer enhancement. The microfluidic flow synthesis approach effectively enhances mixing efficiency at various flow rates, enabling continuous and high-throughput synthesis of boehmite nanofluids with different morphologies. The synthesized nanofluids exhibit long-term stability (>50 days) at room temperature. Both rod- and sphere-shaped nanofluids under equivalent concentrations can significantly improve critical heat flux (CHF) and maximum heat transfer coefficient (HTC) across various operating parameters, but with similar enhancement characteristics. Analysis of the period of bubble growth and burst, bubble size distributions, number of bubbles, and vapor phase fractions reveals that rod- and sphere-shaped nanofluids could shorten the period, enhance surface wetting, increase nucleation sites, and reduce bubble size efficiently and similarly. Furthermore, the effect of the concentration of nanofluid on phase-change heat transfer performance is systematically explored. 0.01 wt% nanofluid behaves the most remarkable enhancement, CHF and maximum HTC are improved by 24 % and 14.4 %, respectively. These findings not only shed new light on the controllable synthesis of functional nanomaterials but also provide important guidelines for the rational design of nanofluids for efficient two-phase cooling of electronic devices. [ABSTRACT FROM AUTHOR]

Cemented paste backfill mining technology that recycling tailings and waste rocks can effectively reduce heat damage. Heat pipe exchangers, demonstrating much higher thermal conductivity than water pipe exchangers, led to the development of a novel phase change backfill body system with a built-in casing heat pipe exchanger (HP-PCB). Numerical analysis revealed that, for the melt and solidification of a large amount of PCM, the temperature step phenomenon was observed at both heat storage and heat storage/heat release coexistence stages. Increased surrounding rock temperatures enhanced heat storage and heat release capacities, but reduced system energy efficiency. The optimal water flow velocity was identified at the laminar-turbulent transition flow rate, 0.32 m/s. An increase in water inlet temperature resulted in lower heat release capacity and system energy efficiency. The energy efficiency of the HP-PCB system exceeded that of the traditional water pipe-backfill system by 37.22%. At a surrounding rock temperature of 45 °C, cooling water velocity of 0.32 m/s, and a 6 °C inlet water temperature, the HP-PCB system achieved its highest energy efficiency coefficient, 86.38%. These findings highlight the HP-PCB system potential for efficient geothermal energy extraction in mine. [ABSTRACT FROM AUTHOR]

Solar cavity receiver is quite often utilized in the solar tower power system. It is a photo-thermal conversion component, which absorbs solar radiation energy and heats the working fluid. The safety and thermal efficiency of solar cavity receiver can directly affect the efficiency of the entire power system. In this paper, a modified combined method is proposed to simulate the thermal performance of a saturated water/steam solar cavity receiver. Compared with the combined method presented previously, this modified one can describe the whole steady process of the receiver and accurately estimate the steady-state efficiency and the mass flow rate of the generated steam in the boiling tubes. Under the given boundary condition of incident solar flux, the modified method is adopted to find an optimized distribution of absorptivity in the solar wavelength band for the absorber surfaces in order to improve the uniformity of surface heat flux distribution. The simulation results show that the uniformity of surface heat flux is improved effectively and the maximum mean square deviation of the external tube temperature drops from 32.4 °C to 23.6 °C after optimizing. Based on the relatively uniform heat flux distribution, the effect of thermal emissivity of the absorber surfaces on the thermal performance of the cavity receiver is further investigated. Being different from those of parabolic trough and external cylindrical receivers, both the radiative and the convective heat loss of the present cavity receiver decrease with increasing thermal emissivity, which improves the receiver’s efficiency. These results can provide a useful reference for the design and selection of surface coatings for the cavity receivers. [ABSTRACT FROM AUTHOR]

Intracranial vertebrobasilar atherosclerosis is the main cause of posterior circulation ischemic stroke. We aimed to construct a predictive model for the risk of posterior circulation ischemic stroke in patients with posterior circulation atherosclerosis based on high-resolution MRI (HR-MRI). A total of 208 consecutive patients with posterior circulation atherosclerosis confirmed by HR-MRI, from January 2020 to July 2021, were retrospectively assessed. They were assigned to the posterior circulation stroke (49 patients) and non-posterior circulation stroke group (159 patients) based on clinical presentation and diffusion-weighted imaging (DWI). Demographic data, risk factors of atherosclerosis, laboratory findings, and imaging characteristics were extracted from electronic health records. Plaque features were investigated by HR-MRI. Fifty-three clinical or imaging features were used to derive the model. Multivariable logistic regression analysis was employed to construct the prediction model. The nomogram was evaluated for calibration, differentiation, and clinical usefulness. Plaque enhancement, plaque irregular surface morphology, artery location of plaque, and dorsal quadrant of plaque location were significant predictors for posterior circulation stroke in patients with intracranial atherosclerosis. Subsequently, these variables were selected to establish a nomogram. The model showed good distinction (C-index 0.830, 95% CI 0.766-0.895). The calibration curve also showed excellent consistency between the prediction of the nomogram and the observed curve. Decision curve analysis further demonstrated that the nomogram conferred significantly high clinical net benefit. The nomogram calculated from plaque characteristics in HR-MRI may accurately predict the posterior circulation stroke occurrence and be of great help for stratification of stroke decision making. [ABSTRACT FROM AUTHOR]

Core-shell structure (FA@SiO 2) pore former is employed to fabricate high porosity and low mechanical behavior loss vitrified bond diamond abrasive tools. Four different pore former contents i.e. 2, 4, 6, and 8 wt% are used to fabricate the composites. The effects of content of the FA/FA@SiO 2 on the phase, morphology structure, open porosity, fracture strength, as well as Rockwell hardness of the FA/FA@SiO 2 pore former in the composite are investigated. With increasing FA/FA@SiO 2 content from 0 to 8 wt%, open porosity of the composites increases significantly and fracture strength drops ~15%. As compared with FA composite, FA@SiO 2 composite exhibits improved pore structures, thus suppressing dramatically bending strength loss and grade loss while remains high porosity. Moreover, the FA@SiO 2 in the matrix facilitates the enhancement of interfacial debonding owing to the high contact area, supported SiO 2 interlayer and processes of early crack capture at FA@SiO 2 /glass matrix interface. Therefore, the 4 wt% FA@SiO 2 composite shows superior bending strength and hardness (65.08 MPa; 46.25 HRB), which are 15% and 37% higher than those of 4 wt% FA composites (56.33 MPa; 33.67 HRB). Unlabelled Image • High porosity and low mechanical behavior loss vitrified bond diamond abrasive tools were fabricated. • FA@SiO 2 spheres were synthesized via a modified Stöber method treatment of original FA. • The network structure of Borosilicate glass was studied by 27Al and 29Si nuclear magnetic resonance (NMR). • The FA@SiO 2 specimens presented smooth pores surfaces and good interfacial debonding between pores and verified matrix. [ABSTRACT FROM AUTHOR]

Low-concentration and low-profile compound parabolic concentrators (CPCs) in the quasi-stationary state were designed and investigated for potential use in rooftop and building-integrated concentrating photovoltaic–thermal applications. All the designs were investigated with a geometric concentration ratio of two. The first design was the lowest-position-truncated CPC (LEMR), and the second was the highest-position-truncated CPC (HEMR). The performances of both concentrators were compared with a full CPC (without truncation). At the outlet aperture, the optical efficiency within the half acceptance angle for the LEMR and HEMR CPCs averaged nearly 97%, whereas for the full CPC, it was 95%. At the best concentration plane (BCP), the optical efficiency within the half acceptance angle was the highest for the LEMR CPC 95%. A distributive method was used to estimate accurately the nonuniformity in the solar flux at both the outlet and the BCP. The nonuniformity analysis revealed that the LEMR and HEMR designs exhibited a uniform distribution of solar flux at the BCP. The incident-angle modifiers for all three cases were investigated, and the annual accumulated solar energy was estimated for Xi'an, China. The material consumption of the LEMR CPC was approximately 48% that of the full CPC and 78% that of the HEMR CPC. The LEMR also exhibited the highest annual-energy efficiency per unit material consumption (ηm = 1.30). Finally, the results indicate that the LEMR CPC possesses higher solar flux uniformity and represents a better trade-off between energy collection and cost reduction, and thus, the novel design can be used as a quasi-stationary concentrator. [ABSTRACT FROM AUTHOR]

• An experimental investigation of flow boiling on micro-pin-fined surfaces in a horizontal narrow microchannel was performed. • The CHF and HTC were enhanced up to 51% and 240%, respectively. • The bubble behaviors were captured to explain the heat transfer enhancement mechanism. • A new correlation was proposed to predict flow boiling HTC in the microchannel by considering the micro-pin-fins. In this paper, an experimental investigation of flow boiling in a horizontal narrow microchannel with hydraulic diameter of D h = 952 μm was conducted. Flow boiling heat transfer characteristics of micro-pin-finned surfaces were evaluated over the mass fluxes range from 200 - 500 kg/m2s (corresponding flow velocity: 0.2 - 0.5 m/s), using deionized water as the working fluid with different inlet temperatures T in = 30 - 50 °C. The outlet pressure of the microchannel was about 1 atm. The boiling curves, heat transfer coefficients, bubble behaviors and heat transfer enhancement mechanism were discussed with the variation of heat flux, mass flux and inlet temperature. The results indicated that the micro-pin-finned surfaces could improve the critical heat flux (CHF) and heat transfer coefficient (HTC) greatly due to numerous nucleate sites and large heat transfer area enhancement ratio. The CHF up to 360 W/cm2 has been demonstrated at a mass flux of 500 kg/m2s. Compared with a smooth surface, a 240% higher heat transfer coefficient (18.4 W/cm2K) on the S30-120 surface has been achieved at a mass flux of 500 kg/m2s with an inlet temperature of 30 °C. The boiling curves of the micro-pin-finned surfaces presented an obvious "hook back" phenomenon after reaching the onset of the nucleate boiling (ONB) and then the wall temperature had a slight rise with the increase of the heat flux. Moreover, the intensive micro-pin-finned arrangements showed a significant wicking effect and promoted liquid replenishment, which could destroy the liquid boundary and enhance turbulence. The bubble behaviors were also captured to explain the heat transfer enhancement mechanism in a horizontal narrow microchannel. [ABSTRACT FROM AUTHOR]

[Display omitted] • The property and influence of Ni supported on 5 zeolites on SCWG of lignin were studied. • The order of catalytic activity on SCWG: Ni/4A > Ni/3A > Ni/5A > Ni/13X > Ni/ZSM-5. • The superiority of type-A zeolites over ZSM-5 as Ni support was the proper-size pores. • H 2 yield was increased by 1.9 times with catalysis of 30 wt% Ni loaded on 4A zeolite. In the present study, supercritical water gasification of dealkaline lignin catalyzed by Ni supported on different zeolites (3A, 4A, 5A, 13X and ZSM-5) was investigated. Scanning electron microscopy-energy dispersive X‐ray spectrometry (SEM-EDS), N2 adsorption–desorption and X-ray diffraction (XRD) were used to characterize the catalyst. Most of these catalysts enhanced the gasification except Ni/ZSM-5, and the order of their catalytic activity was: Ni/4A > Ni/3A > Ni/5A > Ni/13X > Ni/ZSM-5. The higher activity of Ni/4A was probably because it has mesopores with proper size to disperse Ni and provide more active sites for the reaction. With the catalysis of Ni/4A, the hydrogen selectivity was increased from 27.07% to 42.61%, and the H 2 yield increased from 3.14 mol/kg to 5.63 mol/kg. With Ni/4A, the prolongation of reaction time improved the gasification efficiency and hydrogen production, but its impact became less pronounced when it was above 20 min. The increase of the Ni loading amount from 0 to 30 wt% in Ni/4A improved the hydrogen yield by 1.9 times to 6.2 mol/kg, but its further increase from 30 wt% to 50 wt% had less influence. [ABSTRACT FROM AUTHOR]

Abstract: Experiments were conducted to study the subcooled flow boiling heat transfer performance of FC-72 over silicon chips. For boiling heat transfer enhancement, two kinds of micro-pin-fins having fin thickness of 50 μm and fin heights of 60 and 120 μm, respectively, were fabricated on the silicon chip surface with the dry etching technique. The fin pitch was twice the fin thickness. The experiments were conducted at the fluid velocities of 0.5, 1 and 2 m/s and the liquid subcoolings of 15, 25 and 35 K. The micro-pin-finned surfaces showed a sharp increase in heat flux with increasing wall superheat and a large heat transfer enhancement compared to a smooth surface. The nucleate flow boiling curves for the two micro-pin-finned surfaces collapsed to one line showing insensitivity to fluid velocity and subcooling, while the critical heat flux values increased with fluid velocity and subcooling. The micro-pin-finned surface with a larger fin height of 120 μm provided a better flow boiling heat transfer performance and a maximum critical heat flux of 145 W/cm2. The wall temperature at the critical heat flux for the micro-pin-finned surfaces was less than 85 °C for the reliable operation of LSI chips. [Copyright &y& Elsevier]

Abstract: For the purpose of cooling electronic components with high heat flux efficiently, some experiments were conducted to study the flow boiling heat transfer performance of FC-72 on silicon chips. Micro-pin-fins were fabricated on the chip surface using a dry etching technique to enhance boiling heat transfer. Three different fluid velocities (0.5, 1 and 2m/s) and three different liquid subcoolings (15, 25 and 35K) were performed, respectively. A smooth chip (chip S) and four micro-pin-finned chips with the same fin thickness of 30μm and different fin heights of 60μm (chip PF30–60) and 120μm (chip PF30–120), respectively, were tested. All the micro-pin-finned surfaces show a considerable heat transfer enhancement compared to the smooth one, and the critical heat flux increases in the order of chip S, PF30–60 and PF30–120. For a lower ratio of fin height to fin pitch and/or higher fluid velocity, the fluid velocity has a positive effect on the nucleate boiling curves for the micro-pin-finned surfaces. At the velocities lower than 1m/s, the micro-pin-finned surfaces show a sharp increase in heat flux with increasing wall superheat, and the wall temperature at the critical heat flux (CHF) is less than the upper limit, 85°C, for the reliable operation of LSI chips. The CHF values for all surfaces increase with fluid velocity and subcooling. The maximum CHF can reach nearly 150W/cm2 for chip PF30–120 at the fluid velocity of 2m/s and the liquid subcooling of 35K. [Copyright &y& Elsevier]