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The prediction of dose distribution in volumetric modulated arc therapy (VMAT) plays a curial role in radiotherapy. Accurate VMAT dose prediction for prostate cancer is always a great challenge because of the complexity of the VMAT dose distributions and the low contrast of the organs and tissues in the male pelvic CT images. In this paper, a novel progressive refinement UNet (PRUNet) with rank loss is proposed to address the aforementioned problem. On the one hand, the proposed PRUNet extends the traditional UNet with a novel progressive refinement module to generate more realistic dose distributions. The progressive refinement module generates multiple dose predictions with different resolutions in one forward pass and refines the dose prediction with predicted details at finer levels from lower resolution to higher resolution. On the other hand, it turns out that the dosimetric metrics are sensitive to the order relation among the dose values in dose distributions. A new rank loss function is proposed to optimize the similarity between the order relations among the dose values in dose predictions and that in real dose distributions. The proposed PRUNet is trained in a multi-task framework to jointly learn the dose distribution and the order relation among dose values. To evaluate the performance of the proposed PRUNet, the VMAT dose distributions and anatomical information of 64 prostate cancer patients are collected. The proposed model generates more accurate dose distributions with better quantitative dosimetric metrics than the state of the art UNet models do.

Ultrasonography of the breast mass is an important imaging technology for diagnosing breast cancer. In China, ultrasound equipment is widely used in medical institutions. Patients obtain a report with highlighted ultrasonography images through an initial clinical screening. However, analyzing these images manually is highly subjective for the variation in the clinical competence of doctors, resulting in poor consistency and low sensitivity. In this study, an automated breast cancer diagnosis system is developed to increase diagnostic accuracy. The system is deployed on mobile phones, takes a photo of the ultrasound report as input and performs diagnosis on each image. The developed system consists of three subsystems. The first subsystem is to reduce noise in the taken photos, reconstructing high-quality images. We develop the first subsystem based on the frameworks of stacked denoising autoencoders and generative adversarial networks. The second subsystem is to classify images into malignant and non-malignant; to extract high-level features from the images, deep convolutional neural networks are employed. The third subsystem is to detect anomalies in model performances, reducing false negative rates. Generative adversarial networks are utilized to distinguish false negative samples from true negative samples. 18225 breast ultrasonography images and 2416 ultrasound reports are collected to train and evaluate the system. Experimental results show that the performance of our system is comparable to that of human experts. It is believed that this is the first system for breast cancer diagnosis deployed on mobile phones. The developed system is integrated with a cloud computing platform and accessible online to aid in the initial screening and diagnosis of breast cancer, thereby promoting earlier treatment, reducing the morbidity and mortality.

Lithium-sulfur battery is desirable for the future potential electrochemical energy storage device with advantages of high theoretical energy density, low cost and environmental friendliness. However, some natural hindrances, particularly fast capacity degradation resulting from the migration of dissolved polysulfide intermediates, remain to be significant challenges prior to the practical applications. In this work, a composite interlayer of carbon nanofibers (CNFs) which are enriched by Co-based metal organic frameworks (ZIF-67) growth in-situ is exploited. Notably, physical blocking and chemical trapping abilities are obtained synergistically from the ZIF/CNFs interlayer, which enables to restrain the dissolution of polysulfides and alleviate shuttle effect. Moreover, the three-dimensional fiber networks provide an interconnected conductive framework between each ZIF microreactor to promote fast electron transfer during cycling, thus contributing to excellent rate and cycling performance. As a result, Li-S cells with ZIF/CNFs interlayer show a high specific capacity of 1334 mAh g−1 at 1 C with an excellent cycling stability over 300 cycles. Besides, this scalable and affordable electrospinning fabrication method provides a promising approach for the design of MOFs-derived carbon materials for high performance Li-S batteries.

Premixed hydrogen/air micro-flame stabilizations in a narrow channel confined by two parallel plates with thermally isotropic and orthotropic wall materials are numerically studied using a OpenFOAM-based, reacting flow code. For a range of simulated equivalence ratios and inflow velocities, two modes of flame shapes (convex-shaped and concave-shaped) are observed, accompanying with variations of the number of heat release rate peaks in flame structures, which can be attributed to the appearance of some critical O-participating and H-participating elementary reactions. Flame stability limits are studied for three sets of wall thermal conductivities of k = 16 W/m K, k = 128 W/m K (isotropic) and k x x = 128 W/m K & k y y = 16 W/m K (orthotropic). The low velocity limits show invariant with wall thermal conductivities, while the high velocity limits in descending order are found to be: “k = 128 W/m K” > “ k x x = 128 W/m K & k y y = 16 W/m K” > “k = 16 W/m K”. The logic behind is the competition between two mechanisms: the wall pre-heating effects and the transverse heat losses to the ambient. The critical convective heat transfer coefficients that reflect the combustor's ability to resist heat losses are also investigated among the three cases. The reduction of the transverse thermal conductivity can have a high critical coefficient value in the low-inflow velocity regime while makes negligible impacts on extending the critical coefficient in the high-inflow velocity regime. In summary, the use of thermally orthotropic wall materials leads to a slightly decreased high velocity limit ( ~ 3% lower) but a considerably increased critical convective heat transfer coefficient in the high-inflow velocity-regime ( ~ 25% higher), as compared to the thermally isotropic combustor of k = 128 W/m K.

There is a noticeable gap in diagnostic evidence strength between the thick and thin scans of Low-Dose CT (LDCT) for pulmonary nodule detection. When the thin scans are needed is unknown, especially when aided with an artificial intelligence nodule detection system.A case study is conducted with a set of 1,000 pulmonary nodule screening LDCT scans with both thick (5.0mm), and thin (1.0mm) section scans available. Pulmonary nodule detection is performed by human and artificial intelligence models for nodule detection developed using 3D convolutional neural networks (CNNs). The intra-sample consistency is evaluated with thick and thin scans, for both clinical doctor and NN (neural network) models. Free receiver operating characteristic (FROC) is used to measure the accuracy of humans and NNs.Trained NNs outperform humans with small nodules6.0mm, which is a good complement to human ability. For nodules6.0mm, human and NNs perform similarly while human takes a fractional advantage. By allowing a few more FPs, a significant sensitivity improvement can be achieved with NNs.There is a performance gap between the thick and thin scans for pulmonary nodule detection regarding both false negatives and false positives. NNs can help reduce false negatives when the nodules are small and trade off the false negatives for sensitivity. A combination of human and trained NNs is a promising way to achieve a fast and accurate diagnosis.

“Flame-street” refers to the interesting combustion phenomenon that a diffusion flame in a narrow channel is separated into a discrete series of flame segments. Although flame-street has been observed experimentally for more than a decade, numerical simulations of this phenomenon with realistic chemistry and detailed analysis of its thermo-chemical structures have yet to be performed. In this paper, the methane-oxygen diffusion flame-street observed by Misse et al. (2005) [36] in a microchannel was numerically reproduced using a reacting flow solver developed based on the open-source framework OpenFOAM. The main purpose of the present work is to investigate the detailed thermo-chemical structures of diffusion flame-street in the anticipation of a deep understanding of the underlying mechanisms responsible for its formation. Our simulation results show that the presence of discrete flame segments can strongly affect the flow field. In addition, the flame-street was found to consist of a bibrachial leading flame with a long diffusion tail and a much weaker fuel-lean premixed branch, and consecutive downstream “new moon”-like flamelets each with a fuel-lean and a fuel-rich premixed branch. Chemical structures of these flame branches were analyzed by examining critical reactions that contribute significantly to the overall heat release. Finally, the effects of channel wall thermal conditions and species mass diffusion on the formation of the flame-street were investigated. It was found that the flame street could be established only at a moderate level of heat loss to the wall: significantly enhanced or reduced heat losses would result in either a single short edge flame or a long continuous edge flame. Increased mass diffusivity was seen to enhance combustion, elongate the leading flame, and even lead to more flame segments that appeared within the channel, although they may exist in a unsteady mode, being repetitively split, moving downstream and being blown-out/extinguished.

This paper computationally investigates the turbulent heat transfer of sCO flows cooled in large horizontal tubes with diameter of 15.75 mm, 20 mm and 24.36 mm using RANS turbulence models. The numerical models were validated against experimental data published in literature to demonstrate the reliability of CFD simulations on the heat transfer coefficient prediction and buoyancy effect capture to turbulent sCO. Based on the validated model, a number of computations, involving a wide range of operating conditions, have been carried out. The effect of mass flux (200–800 kg/ms), pressure (8–10 MPa), heat flux (5–36 kW/m) and tube diameter has been analysed. Results demonstrate that the AKN model shows the best consistencies with the experimental measurements and is also able to well reproduce the heat transfer characteristics under various conditions. As the mass flux increases, the heat transfer coefficients go up due to the enhanced turbulence diffusion. Pressure has a significant effect on the distribution of heat transfer coefficient, and its peak drops sharply with rising pressure. At T > T, with the heat flux and tube diameter increasing, sCO heat transfer performance is improved; whereas at T < T, the heat flux and tube diameter almost have no effects on the heat transfer performance. Considerable deviations with the existing heat transfer correlations necessitate the development of a new correlation to predict the heat transfer coefficients of cooling turbulent sCO in large horizontal pipes. Based on the reliable computational datasets, a Nusselt number equation based on the Gnielinski form with the ratio of density incorporated is formulated.

In concentrated solar power (CSP) plants built in dry and arid areas, natural draft dry cooling tower (NDDCT) are commonly employed to dissipate waste heat into the atmosphere. The cooling performance of NDDCT mainly depends on the induced air flow caused by the buoyancy effect. However, the high ambient temperature in summers reduce the cooling efficiency of dry cooling towers and cause significant power loss for CSP plants. To address this problem, spray cooling system utilizing water evaporation was developed to pre-cool the inlet hot air. Different designs of spray cooling systems were proposed and tested on a 20 m high experimental tower. Experimental data were collected to evaluate the performance of the spray cooling system. To our knowledge, this is the world's first attempt to practice spray cooling on a full-scale natural draft dry cooling tower. This study confirms the feasibility and effectiveness of employing spray cooling for cooling performance enhancement of NDDCT. With the goal of maximal cooling effect with least water consumption, the optimal design was proposed, which consists of 3 upward injections at the low level (Height = 2 m), 2 counterflow injections at the middle level (H = 3 m) and 3 counterflow injections at the high level (H = 4 m). The cooling capacity of NDDCT increases from 789 kW to 841.73 kW, as the result of an intensified natural convection. Moreover, in the spray zone, the presence of a low-temperature area is featured by high relative humidity (70%–80%). The intensified natural convection caused by pre-cooled air and the presence of high vapour concentration are attributed to spray evaporation, which confirms the necessity to introduce the spray cooling system.

A novel coaxial eccentric indexing cam mechanism (CEC) is proposed for high-speed automatic machineries. In comparison with the conventional indexing cam mechanisms such as parallel, globoidal, cylindrical cam mechanisms as well as the Geneva mechanism, the merits of this novel mechanism are: (1) more compact structure and (2) higher indexing rate. The structure and transmission principle of the mechanism are introduced and the cam profiles are formulated with an emphasis to derive two design criteria. The influences of the geometric parameters on the kinematic performance of the mechanism are also discussed through significant numerical analyses. Finally, the dynamic performance of a virtual prototype is analyzed with the aid of SolidWorks, and the physical prototype is manufactured to verify the validity of this design.

Recent studies have shown that ceramic particles reinforced high entropy alloy (HEA) has attracted increased attention due to their excellent strength and wear resistance. In this work, the directional array TiN-reinforced AlCoCrFeNiTi HEA coating was synthesized via magnetic field-assisted laser cladding. Besides, the wear resistance of HEA coating was systematically investigated. The atomic structure, ideal adhesion work (Wad) and electronic structure of the interface between matrix and TiN were calculated by first principles method. The results show that the microstructures of in-situ TiN display a “cross” shape of the directional array, and a coherent interface in TiN (2 0 0)/(Ni, Co)Ti2 (5 1 1) and the high bonding strength between TiN and BCC improve the wear resistance of HEA coating.

Currently, the preparation and application of functional waterborne polyurethane has become a research hotspot in the field of polyurethane. In the present work, Different weight ratios of diacetyl oxime and coumarin diol were used as the reactive filler with isophorone diisocyanate (IPDI) and Poly propylene glycol (PPG) to prepare superior amine-response, self-healing and recyclable waterborne polyurethane films (WPU-x). Dynamic mechanical analysis was carried out to identify the self-healing properties of WPU-x. It was revealed that the WPU-2 film show an excellent self-healing capability based on the combination of the mobility of the soft segment, dynamic reaction of oxime carbamate bond and hydrogen bonds, and the mechanical properties self-healing efficiency can reach 91.11% after self-healing at 90 °C for 7 h. UV testing and fluorescence imaging results shown that WPU-2 film exhibit a rapid and concentration-dependent response to dimethylamine (DMA), and it also shows varying degrees of response to other organic amines. The WPU-2 film could be readily applied in cold chain transportation of shrimp and fish for real-time and visual monitoring the freshness of seafoods. At the same time, the WPU-2 film could be recycled via hot-pressing and solution casting. Therefore, this strategy provides some insights for preparing multi-functional waterborne polyurethane.

This paper presents the results of computational investigations on cooling heat transfer of turbulent sCO2 in three horizontal tubes with diameter of 15.75 mm , 20.00 mm and 24.36 mm using RANS turbulence models at a pressure of P = 8.0 MPa . Four models with good prediction performance demonstrated in literature (RNG k - e model and three other low-Reynolds number k - e models of LS, YS and AKN) have been validated against experimental measurements and to observe that results from the AKN model are closer to experimental data. Details of heat transfer behaviour of sCO2 cooled in horizontal tubes within this diameter range are revealed and the influence of heat flux, tube diameter and buoyancy on heat transfer performance have been discussed. Results demonstrate that at T b > T pc (pseudocritical temperature), sCO2 heat transfer performance is enhanced as the heat flux and tube diameter increase; whereas at T b T pc , the heat flux and tube diameter almost do not affect the heat transfer performance. The buoyancy effect only generates slight enhancement for turbulent heat transfer from sCO2 flowing in horizontal tubes with large diameters. However, as the values of Richardson number Ri that quantifies the buoyancy effects continue increasing within Ri > 0.1 , the buoyant force is enhanced, which in turn impairs the heat transfer near T pc . This is a result contrary to past reports confined to small diameter tubes, which is mainly attributed to the accumulation of denser cold fluids at the bottom of the pipe when buoyancy effects are strong.

Composite sulfide Fe0.5Co0.5S2 used as cathode material in thermal batteries can be prepared through traditional high-temperature solid-state method and liquid phase method, which combines precipitation and high temperature sulfuration. The single cells with S-Fe0.5Co0.5S2 and L-Fe0.5Co0.5S2 exhibit discharge capacities of 1547.17 A s g−1 and 1872.89 A s g−1 with the cut-off voltage of 1.25 V. For comparison, the single cell with FeS2 also discharged, demonstrating a discharge capacity of 1221.45 A s g−1. Moreover, the physical properties and electrochemical behaviors of L-Fe0.5Co0.5S2 are obviously superior to that of S-Fe0.5Co0.5S2. Due to its excellent electrochemical properties, Fe0.5Co0.5S2 compound, especially synthesized by liquid phase method, can be used as cathode material instead of FeS2 for thermal batteries.

In this study, the film cathode for thermal batteries with wonderful reproducibility and homogeneity is fabricated and investigated. The film cathode is prepared by screen printing process. A single cell with a 50 µm film cathode using screen printing process exhibited a specific capacity of 2092.61 As g−1. For comparison, a single cell with a 600 µm pellet cathode is also discharged, demonstrating a specific capacity of 1076.65 As g−1. These significant improvements can be attributed to the optimal thickness of cathode. The film cathode also exhibited excellent utilization of the electrode material and excellent mechanical strength making it applicable to thermal batteries.

Buoyancy has been found to have a significant influence on the flow and heat transfer behaviors of turbulent sCO2. This paper uses the computational method to investigate the flow and heat transfer characteristics of turbulent sCO2 in a large horizontal tube with the buoyancy effects taken into account, RNG and three selected low-Reynolds number k - e turbulence models have been validated against experiments published in literatures. Using the validated CFD model, the buoyancy mechanisms affecting sCO2 flow and heat transfer within large horizontal tubes are revealed, and the effect of the heat flux have been analyzed. Comparison against experimental results suggests that AKN low-Reynolds number model exhibits the best prediction. Buoyancy influences the flow structure and turbulence levels mainly via the induced secondary circulation. Buoyancy effects are stronger at increased heat flux values. The secondary circulation becomes pronounced at higher heat flux levels and increases the temperature difference between the top and bottom tube surfaces. In large horizontal tubes, slight heat transfer enhancements in the mixed convection are observed near the pseudocritical point. However, a significant deterioration is found at higher heat load density. This is a result contrary to past reports confined to small diameter tubes.

Introduction Many cell types (including muscle cells and fibroblasts) can contract at physiological conditions and their contractility may change during tissue injury and repair or other diseases such as allergy and asthma. The conventional gel contraction assay is commonly used to monitor the cellular contractility. It is a manual assay and the experiment usually takes hours even days to complete. As its readout is not always accurate and reliable, the gel contraction assay is often used to qualitatively (but not quantitatively) characterize cellular contractility under various conditions. Method To overcome the limits of the gel contraction assay, we developed an impedance-based contraction assay using the xCELLigence RTCA MP system. This technology utilizes special 96-well E-plates with gold microelectrode arrays printed in individual wells to monitor cellular adhesion by recording the electrical impedance in real time. The impedance change (percentage vs. control) can be used as the readout for cellular contraction. Results We demonstrated that the impedance-based contraction assay can be performed within 2 h. Using this new method, we quantitatively characterized the effects of several contractile stimulators and inhibitors on human primary bronchial smooth muscle cells and primary lung fibroblasts. Discussion The impedance-based contraction assay can be applied to both basic research and drug discovery for characterizing cellular contraction quantitatively. Because it has high throughput capacity and high reproducibility, the impedance-based contraction assay is useful for high throughput functional screening in drug industry.

Hydroxy-terminated oligomers with narrow molecular weight distribution using as soft segment of polyurethane can significantly increase the modulus, tensile strength, and elongation at break of the polyurethane. Thus, design and synthesis of new hydroxy-terminated oligomers having narrow molecular weight distribution can improve the properties of polyurethane and further expand the use range of polyurethane. A set of side-chain hydroxyl-terminated polybutadiene (HTPB) derivatives were successfully synthesized by anionic polymerization and blue light photocatalytic thiol-ene reaction. Firstly, HTPB with narrow molecular weight distribution was synthesized via anionic polymerization using mono-lithium based initiator and followed by de-protection. Then, HTPB derivatives with different side-chains such as butyl, ethyl acetate, or myristyl, namely HTPBbut, HTPB eac and HTPBtet, were obtained by blue light photocatalytic thiol-ene reaction using Ru(bpy)3Cl2 as photoredox catalyst and HTPB as matrix polymer. Similar with HTPB, those HTPB derivatives also have narrow molecular weight distribution. Polyurethane elastomers (PUs) were synthesized with HTPB or HTPB derivatives as soft segment, toluene diisocynate (TDI) as hard segment, and 1, 4-butanediol as chain extender. Compared study the performances of polymers, the results showed that glass transition temperature (Tg) and viscosity of HTPB derivatives were increased when short-chain side groups were introduced. But instead, Tg and viscosity of HTPB derivatives was reduced following long-chain side groups being grafted. Through comparing research of properties for PUs, tensile strength is reduced and elongation at break is augmented, when side groups were introduced in HTPB backbone. Research on the contact angle tests of PUs indicated that the contact angle of PUs using HTPB, HTPBbut or HTPBeac as soft segment, is similar, and PUs using HTPBtet as soft segment has a larger contact angle about 137.2 °C.

Grassland is an important part of terrestrial ecosystems and contain substantial amounts of soil carbon. However, 90% of grasslands suffer from degradation in northern China, where soil inorganic carbon (SIC) is a major reservoir. Previous studies have focused primarily on soil organic carbon (SOC) stock, while the effects of grassland degradation in SIC stock remains largely unexplored. Therefore, accurate assessments of both SOC and SIC stocks and their profile distributions are necessary to fully understand the role of grassland degradation in China’s carbon budget. Here, we conducted an experiment to estimate the stocks, profile distributions, and environmental controls of both SOC and SIC in patchy saline-alkaline grasslands under three degraded degrees (non-degraded patches, ND; moderately degraded patches, MD, and heavily degraded patches, HD). Our results showed that grassland degradation destroys not only SOC but also SIC stocks in saline-alkaline grasslands. SIC is the main component of soil carbon in saline-alkaline grasslands, and their distributions changed dramatically. Compared with ND, SIC losses caused by degradation accounted for 84% and 86% of total carbon loss under MD and HD patches, respectively. SIC loss primarily occurred at the intermediate soil layers (30–70 cm), while the loss of SOC was mainly in the topsoil (0–40 cm). Moreover, the distributions of SIC from 20 to 60 cm were closely related to soil pH, while it is mainly regulated by EC from 60 to 100 cm. In addition, soil pH, EC, and above-ground biomass were important variables driving the profile distributions of SOC in the upper soil. Our work provides evidence that grassland degradation mainly damages the SIC stocks. Our findings, therefore, highlight the non-negligible role of SIC dynamics in the carbon budget of degraded grassland ecosystems and the need to consider these dynamics in terrestrial carbon cycle research.

Kalina cycle is a promising power cycle to utilize or recover the heat of low-grade heat sources. Most of previous works focused on the thermodynamic and thermoeconomic analysis or optimization for the cycle. In this paper, an off-design mathematical model for Kalina cycle is established to examine the off-design performance of the cycle with the variation of heat source mass flow rate, heat source temperature and cooling water temperature. A modified sliding pressure regulation method, which regulates the turbine inlet pressure to keep the temperature difference between heat source temperature and turbine inlet temperature constant, is applied to control the cycle when off-design conditions occur. The results show that the modified sliding pressure regulation method keeps Kalina cycle with a good off-design performance. With the increase of heat source mass flow rate or heat source temperate, both of the net power output and thermal efficiency increase. With the increase of cooling water temperature, both of the net power output and thermal efficiency decrease. In addition, the turbine efficiency almost keeps the designed value under the off-design conditions.

The nonlocal integrable defocusing coupled nonlinear Schrodinger system from a 3 × 3 spectral problem is investigated. The Backlund transformation of the nonlocal defocusing coupled nonlinear Schrodinger system is presented from the pseudopotentials derived from the Lax pair. The nonsingular localized wave solutions including the breather wave and exponential-rational solutions are obtained, whose evolutions and dynamical properties are discussed.

Herein, a novel composite nanofiber, which consists of TiO-TiO2 heterostructure nanoparticles and boron, nitrogen co-doped carbon nanofibers (BNCNF), has been successfully prepared through a facile electrospinning method. Remarkably, as interlayer for Li S batteries, the TiO-TiO2 heterostructure not only enhances the adsorbability of the interlayer to lithium polysulfides (LiPSs) via the Lewis acid-base interactions, but also accelerates the redox reaction kinetics of the Li S batteries dramatically. Moreover, the BNCNF as a flexible framework can remit the volumetric change of the sulfur cathode, physically retard the migration of LiPSs and chemically adsorb to the LiPSs. Attributing to the synergistic effect of TiO-TiO2 nanoparticle and BNCNF membrane, the Li S batteries with the novel composite interlayer (named as TiO-TiO2/BNCNF) exhibit outstanding cycling stability and high discharge capacity, especially at high current density. With the sulfur loading of 2.5 mg cm−2, the cell with the TiO-TiO2/BNCNF interlayer delivers a high initial discharge capacity of 1014.7 mA h g−1 with a decay rate of 0.092% over 400 cycles at 0.5C, and also possesses excellent initial discharge capacity of 650.0 mA h g−1 with a decay rate of 0.068% over 120 cycles even at 2.0C.

In order to achieve both power and cooling supply for users, a new combined cooling and power system using ammonia–water mixture is proposed to utilizing low grade heat sources, such as industrial waste heat, solar energy and geothermal energy. The proposed system combines a Kalina cycle and an ammonia–water absorption refrigeration cycle, in which the ammonia–water turbine exhaust is delivered to a separator to extract purer ammonia vapor. The purer ammonia vapor enters an evaporator to generate refrigeration output after being condensed and throttled. Mathematical models are established to simulate the combined system under steady-state conditions. Exergy destruction analysis is conducted to display the exergy destruction distribution in the system qualitatively and the results show that the major exergy destruction occurs in the heat exchangers. Finally a thermodynamic sensitivity analysis is performed and reveals that with an increase in the pressure of separator I or the ammonia mass fraction of basic solution, thermal efficiency and exergy efficiency of the system increase, whereas with an increase in the temperature of separator I, the ammonia–water turbine back pressure or the condenser II pressure, thermal efficiency and exergy efficiency of the system drop.

To accelerate the start-up period of Gatton NDDCT, windbreak walls are introduced under the heat exchanger inspired by theoretical analysis, which suggests quicker start-up with increasing values of β, which is a factor that represents the proportion of crosswind redirected into the tower via the heat exchanger by windbreak walls. Three-dimensional (3-D) numerical models at three different wind angles of attack and at crosswind ranging from 1 m/s to 15 m/s produce results consistent with the theoretical analysis. The start-up time with crosswind always follows the similar trend, i.e., first increasing to the peak and decreasing monotonously until a critical speed, beyond which the start-up time keeps almost constant. The air flows through individual heat exchanger bundle due to the interaction between the natural draft (due to heating) and the crosswind effects. These effects are resolved separately at each bundle location at the acting wind speed. Finally, optimum orientations to accelerate the start-up duration are numerically computed. When the wind is mild at up to 4 m/s, windbreak walls are better designed at a 60° wind angle of attack. For crosswind speeds from 5 to 8 m/s, 0° windbreak walls have a better performance. Finally, for wind speeds over 9 m/s, the 30° windbreak walls seem to be most effective. These results should be applicable to any relatively short NDDCT and also imply that at sites with non-uniform wind conditions, a facility to change the windbreak walls orientation with respect to the wind speed would be useful.

A visible-light-responsive hybrid photocatalyst, K-doped g-C3N4/BiOBr, has been synthesized by K-doped g-C3N4 (K–CN) and BiOBr. The property of photocatalysts was characterized by XRD, FT-IR, TEM, SEM, DRS, PL, EIS and HPLC. The photocatalytic activity of K-doped g-C3N4/BiOBr was evaluated by degradation of Rhodamine B (RhB) and tetracycline hydrochloride under visible-light irradiation. The K-doped g-C3N4/BiOBr hybrid photocatalyst which contains K–CN with mass fraction of 20% (20K–CN/BiOBr) shows the best degradation efficiency of RhB. The degradation efficiency of RhB (20 mg/L) can be achieved to 99% and the degradation efficiency of tetracycline hydrochloride by BiOBr decreased with the increase of K-doped g-C3N4 doping. The results of photocurrent and EIS assumed that the tight coupling between K–CN and BiOBr can enhance the separating efficiency of photo-generated carrier. In addition, the capture experiment proof that h+ is the primary active substance in the system of reaction and ·OH is the auxiliary active substance. After five degradation experiments, the efficiency of the degradation of Rhodamine B by the sample can still reach 90%, which proves that the samples are stable. A new and efficient method is provided in this work to solve the pollution of organic dyes and antibiotics.

A novel ternary direct Z-scheme + isotype heterojunction, Δ(Z + H)-scheme photocatalyst CN-TU/BiOBr was fabricated by an effective combination of thermal decomposition and solvothermal method. The samples of g-C3N4 prepared using urea, thiourea and thiourea-urea complexes as precursors were named CN-U, CN-T and CN-TU, respectively. In addition, CN-M was prepared by physically mixing CN-U and CN-T. The structure, morphology, optical and electronic properties of the prepared samples were characterized by XRD, FTIR spectra, SEM-EDS, BET, XPS and DRS. The photocatalytic activities of the synthesized samples were estimated by the degradation of Rhodamine B (RhB), Fluorescein isothiocyanate (FITC) and antibiotic tetracycline hydrochloride (TC) in the presence of visible light. Compared with other as-prepared samples, the ternary 1%CN-TU/BiOBr photocatalyst exhibited an excellent activity, which is attributed to the construction of the ternary Δ(Z + H)-scheme not only benefit to maintain outstanding redox capability of the electrons, but also facilitates the separation of photo-generated carrier. Furthermore, the stability of the sample is tested by cyclic experiments. This work will provided a new insight into optimizing the structure and designing similar Z-scheme photocatalytic system.

Summary Clearance of apoptotic cells by macrophages prevents excessive inflammation and supports immune tolerance. Here, we examined the effect of blocking apoptotic cell clearance on anti-tumor immune response. We generated an antibody that selectively inhibited efferocytosis by phagocytic receptor MerTK. Blockade of MerTK resulted in accumulation of apoptotic cells within tumors and triggered a type I interferon response. Treatment of tumor-bearing mice with anti-MerTK antibody stimulated T cell activation and synergized with anti-PD-1 or anti-PD-L1 therapy. The anti-tumor effect induced by anti-MerTK treatment was lost in Stinggt/gt mice, but not in Cgas−/− mice. Abolishing cGAMP production in Cgas−/− tumor cells, depletion of extracellular ATP, or inactivation of the ATP-gated P2X7R channel also compromised the effects of MerTK blockade. Mechanistically, extracellular ATP acted via P2X7R to enhance the transport of extracellular cGAMP into macrophages and subsequent STING activation. Thus, MerTK blockade increases tumor immunogenicity and potentiates anti-tumor immunity, which has implications for cancer immunotherapy.

An accurate prediction of heat transfer characteristics is essential for the design of bearings in supercritical CO2 power cycles, where the flow at the rotating surface is characterised as Taylor Couette flows. However, the high pressure CO2 leads to Taylor numbers exceeding the applicable range of existing empirical correlations, challenging the suitability. Few studies are found to consider this issue. In this paper, the heat transfer characteristics and windage losses of Taylor Couette flows are investigated. Two representative pressures of 1.4 MPa and 7.8 MPa are studied. It is demonstrated that the heat transfer performance is significantly enhanced at high operation pressures, in particular for the operation temperature towards the critical regime, while a reasonable windage loss is maintained. This is attributed to the increased Taylor number and abrupt changes of thermophysical properties near the critical regime. In addition, empirical correlations underpredict the heat transfer performance, particularly for high operation pressures. The difference is up to three times. The effect of annual gap, cylinder radius and axial length are further compared. This work provides the insight into heat transfer characteristics of Taylor Couette flows operating with CO2. The outcome can be used to the design of CO2 bearings.