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Boosted methanol production over MnOx/ZrO2 catalyst could be achieved via plasma-assisted catalytic CO2 hydrogenation at ambient temperature and pressure.

Three Ru-induced structural interconversion polyoxometalates (POMs), Na

Radiologist is "doctor's doctor", biomedical image segmentation plays a central role in quantitative analysis, clinical diagnosis, and medical intervention. In the light of the fully convolutional networks (FCN) and U-Net, deep convolutional networks (DNNs) have made significant contributions in biomedical image segmentation applications. In this paper, based on U-Net, we propose MDUnet, a multi-scale densely connected U-net for biomedical image segmentation. we propose three different multi-scale dense connections for U shaped architectures encoder, decoder and across them. The highlights of our architecture is directly fuses the neighboring different scale feature maps from both higher layers and lower layers to strengthen feature propagation in current layer. Which can largely improves the information flow encoder, decoder and across them. Multi-scale dense connections, which means containing shorter connections between layers close to the input and output, also makes much deeper U-net possible. We adopt the optimal model based on the experiment and propose a novel Multi-scale Dense U-Net (MDU-Net) architecture with quantization. Which reduce overfitting in MDU-Net for better accuracy. We evaluate our purpose model on the MICCAI 2015 Gland Segmentation dataset (GlaS). The three multi-scale dense connections improve U-net performance by up to 1.8% on test A and 3.5% on test B in the MICCAI Gland dataset. Meanwhile the MDU-net with quantization achieves the superiority over U-Net performance by up to 3% on test A and 4.1% on test B., 10 pages, 6 figures, 6 Table

The movement characteristics of yarn in the profiled reed groove of an air-jet loom can have a great impact on the performance of the fabric. Unstable yarn movement tends to lead to weft defects, as short wefts or weft breaks may occur, which could deteriorate the quality of the final fabric. In this paper, the characteristics of the yarn movement in a profiled reed groove are numerically studied. The arbitrary Lagrangian–Eulerian method is used to solve the two-way airflow–yarn interaction and the yarn is simulated with the ball–socket model. A fluctuation ratio is defined to characterize the unsteadiness of the yarn movement. Our simulation first investigates the effect of the gap ratio of the profiled reed groove (β) on the yarn movement then compares the movements of different yarn kinds. The simulation results indicate that a larger β not only decreases gas leaks (thus saves gas consumption), but also stabilizes the yarn movement. Our simulation results also show that the movement of the yarn of polypropylene is more stable than the other two weft-yarn materials. An experiment is also conducted to validate our numerical results, which shows a favorable agreement between them. Our numerical results of the yarn movement in the profiled reed groove can provide a valuable insight into the optimization of the weft insertion system of the air-jet loom.

In this study, a Eulerian Wall Film (EWF) model and a discrete phase model (DPM) are applied to simulate the phenomenon of droplet re-entrainment in a baffle demister. The primary objective was to ...

Collisions between particles and the wall covered by a liquid layer play an important role in many different industrial processes (e.g., chemical, pharmaceutical, and transportation). Understanding the rebound motion law of the collision between particles and the wall covered by a liquid layer is vital to ensure the high efficiency of processes such as wet granulation and fluid catalytic cracking. In the present study, we investigated the influence of different collision angles on the liquid bridge geometry, particle motions, particle energy, and other collision details based on the oblique collisions between particles and the target plate covered by a liquid layer. Results showed that the collision angle of particles has a great effect on the liquid bridge geometry. Moreover, the liquid bridge caused by different collision angles initially increases the particle deflection angle difference and then decreases, and this influence gradually increases with the increase of the collision angle. In addition, the collision angle greatly affects the particle’s energy.

Tetrameric POM 1 containing the largest number of Rh atoms was successfully synthesized. Results indicate that 1, with a suitable energy band structure, enables the photocatalytic reduction of nitrobenzenes to anilines and catalytic oxidation of anilines to azobenzenes.

Droplet impact on film is a common natural appearance in industrial production. The numerical simulation method is used to simulate the evolution process of droplet impact on different convex surfaces with liquid film to study the influence of various surface structures on the impact of droplets on the film. The mechanism of droplet impact on irregular wall is also explored. The effect of the height and width of the convex on the evolution of the interphase interface and the characteristic parameters of the crown and cavity are discussed. Based on the results, the convex has a great effect on the change form of droplets after impacting the liquid film. A region of high pressure will appear above the convex, and vortices will form around it. In terms of the characteristics of the crown, the growth rate of the crown height increases with the height of the convex. The spreading diameter of the crown increases with the height of the convex. The effect of convex width on the crown is less than that of convex height. The convex has a great influence on the evolution of the cavity, and the convex of different scales will affect the development shape of the cavity. The present finding provides theoretical guidance for the application of droplets impinging on liquid film.

This study systematically investigates the interaction between an oscillating flow and primary cilia using numerical simulations. The primary cilia are modeled as elastic filaments with rotatable basal ends to mimic real ciliary deflections. How some governing parameters [i.e., the peak Reynolds number ( Repeak), Womersley number ( Wo), cilium length ( L*), and streamwise spacing interval ( Ld*)] regulate fluid–cilia interaction is explored. Our results indicate that within a certain range, both the span of deflection (SD) and the maximal curvature increase with the increase in Repeak, L*, and Ld*, while they decrease as the Wo increases. Compared with other parameters, Ld* affects ciliary deflection less significantly and its impact becomes nearly negligible when the cilia are separated over twice their length. Three typical stretch states are captured. For primary cilia with a short or medium length, an increase in the SD is accompanied by a greater propagation distance of the location of the maximal tensile stress (LMTS). However, this is not the case for long cilia that protrude into 1/3 of the lumen, as the arising third stretch state may greatly suppress the LMTS propagation. Our study further confirms the role of primary cilia in decreasing the wall shear stress (WSS) and altering its oscillating feature. The WSS decrease is more significant for cilia undergoing a larger SD and/or when Ld* is reduced. For a constant Ld*, a larger SD corresponds to a more uneven oscillatory shear index distribution, and the affected (i.e., less oscillatory) region appears to greatly depend on Ld*.

Cancer is an important factor threatening human life and health; in recent years, its morbidity and mortality remain high and demosntrate an upward trend. It is of great significance to study its pathogenesis and targeted therapy. As the complex mechanisms of epigenetic modification has been increasingly discovered, they are more closely related to the occurrence and development of cancer. As a reversible response, epigenetic modification is of great significance for the improvement of classical therapeutic measures and the discovery of new therapeutic targets. It has become a research focusto explore the multi-level mechanisms of RNA, DNA, chromatin and proteins. As an important means of cancer treatment, radiotherapy has made great progress in technology, methods, means and targeted sensitization after years of rapid development, and even research on radiotherapy based on epigenetic modification is rampant. A series of epigenetic effects of radiation on DNA methylation, histone modification, chromosome remodeling, RNA modification and non-coding RNA during radiotherapy affects the therapeutic effects and prognosis. Starting from the epigenetic mechanism of tumorigenesis, this paper reviews the latest progress in the mechanism of interaction between epigenetic modification and cancer radiotherapy and briefly introduces the main types, mechanisms and applications of epigenetic modifiers used for radiotherapy sensitization in order to explore a more individual and dynamic approach of cancer treatment based on epigenetic mechanism. This study strives to make a modest contribution to the progress of human disease research.

Ga-doped ZSM-5 zeolites were directly synthesized by a facile one-step hydrothermal method without organic templates and calcination and then investigated in the cyclohexene hydration reaction. The structure, component, textural properties, and acidity of the as-prepared samples were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence (XRF), Brunauer-Emmett-Teller (BET), ammonia temperature-programmed desorption (NH

Centrifugal pumps as turbines (PATs) are widely used in chemical engineering for recycling the abundant energy from high-pressure fluid. The operation of PATs is significantly affected by their upstream conditions, which are not steady (i.e., with a constant flow rate) in reality, thus, research on the flow mechanism of PATs under transient conditions should be considered of higher importance. In this study, a numerical model of a PAT was developed by employing the sliding mesh method to describe turbine rotation, and a user-defined function (UDF) for characterizing transient flow conditions. Corresponding experiments were also conducted to provide validation results for the simulation, and the simulation results agreed well with the experimental outcomes. The instantaneous characteristic curves under the current working conditions were obtained for different transient flow rates. The results show that the turbine’s efficiency is significantly affected by transient flow conditions. In particular, a rapid increase (large time derivative) of flow rate results in a large energy dissipation at the turbine outlet, and therefore, the turbine efficiency decreases. In addition, as the flow rate increases, the hydrodynamic force on the impeller, and the pressure fluctuation amplitude in the volute first decrease and then increase, reaching the minimum near the design flow rate. The current study provides a reliable and precise approach for the estimation of hydrodynamic performance of fluid machinery under transient flow conditions.

The deflector and the rod bank are commonly used to optimize flue gas distribution in the original spray tower (OST) of a wet flue gas desulfurization system (WFGD). In this paper, the internal optimization mechanism of the deflector desulfurization spray tower (DST) and the rod bank desulfurization spray tower (RBST) are studied. Based on the Euler–Lagrange method, the standard k-ε turbulence model, an SO2 absorption model and a porous media model, the numerical simulation of the desulfurization spray tower is carried out with the verification of the model rationality. The results show that there are gas-liquid contact intensification effects in DST and RBST. Compared with OST, gas-liquid contact intensification enhances the heat and mass transfer effects of DST and RBST. The temperature difference between inlet and outlet of flue gas increased by 3.3 K and the desulfurization efficiency of DST increased by 1.8%, the pressure drop decreased by 37 Pa. In RBST, the temperature difference between the flue gas inlet and outlet increased by 5.3 K and the desulfurization efficiency increased by 3.6%, the pressure drop increased by 33 Pa.

Fluid–structure interaction (FSI) phenomenon is very common in pneumatic-type textile field. However, the motion of flexible bodies, for instance, fibers or yarns, are usually difficult to simulate due to their large fineness ratio and high flexibility. Conventional FSI solvers based on the body-fitted grid method are difficult to handle the large deformation due to severe grid distortion. In this paper, we studied the fluid–fiberinteraction for fiber conveyance in a fiber transport channel (FTC) using the immersed boundary-lattice Boltzmann method (IB-LBM). The effect of three parameters on fiber conveyance, i.e. the conical degree of the FTC ( tan α ), the bending rigidity of fiber ( K ˆ b ) and the flow Reynolds number ( R e ), are particularly investigated. The calculated results indicate that the converging shape of FTC helps to straighten fiber and adjust its orientation to a more horizontal degree during the conveyance, however, it may not improve fiber delivery efficiency. A larger conical degree would bring a better straighten effect and a smaller leading angle if fiber-wall contact does not occur. Under the conditions that tan α > 0 , R e 400 and K ˆ b 1 e − 3 , the straightness undergoes a “leap–slump–grow–drop” evolution process and the leading angle follows an “increase–decline” tendency. Moreover, the simulation results show that the bending rigidity have a significant effect on fiber configuration and orientation during its conveyance. A fiber with a larger bending rigidity is more likely to maintain a straighter configuration and a more horizontal orientation during its conveyance. As R e increases in simulations, the fiber gets less straight in configuration and more vertical in orientation, and deviates more from the horizontal path.

Understanding light propagation in skin tissues with complex blood vessels can help improve clinical efficacy in the laser treatment of cutaneous vascular lesions. The voxel-based Monte Carlo (VMC) algorithm with simple blood vessel geometry is commonly used in studying the law of light propagation in tissues. However, unavoidable errors are expected in VMC because of the zigzag polygonal interface. A tetrahedron-based Monte Carlo with extended boundary condition (TMCE) solver is developed to discretize complex tissue boundaries accurately. Tetrahedra are generated along the interface, resulting in a polyhedron approximation to match the real interface. A comparison between TMCE and VMC shows neglected differences in the overall distribution of energy deposition of different models, but poor adaptability of the curved tissue interface in VMC leads to a higher energy deposition error than TMCE in a mostly deposited region in blood vessels. Replacing the real blood vessel with a cylinder-shaped vessel shows an error lower than that caused by VMC. Statistical significance analysis of energy deposition by TMCE shows that mean curvature has stronger relationship with energy deposition than the Gaussian curvature, which indicates the importance of this geometric parameter in predicting photon behavior in vascular lesions.

Air pollution in trains is an important factor threatening human health, which has attracted more and more attention in the worldwide public health researches. In this study, one cabin of a fully enclosed train was taken as an example to conduct experimental and numerical research on pollution level and distribution characteristic of total volatile organic compound (TVOC). The results show that when the average emission rate under daily environmental conditions was taken as the reference, TVOC concentration in the cabin exceeded the limit level of Chinese Indoor Air Quality Standard by more than 4 times. The obvious pollutants accumulative phenomenon could be found at bottoms and corners under the action of airflow. Setting air inlets at the roof of the train, mean age of air ranged from 30 s to 50 s in the breathing area. The concentration of pollutants was the lowest at 2.5–5 m from the center point of the cabin structure, and the ventilation efficiency was the highest. The introduction of clean fresh air could effectively eliminate pollutants. When the complete displacement ventilation rates were 51.4 h−1 and 28.6 h−1, the removal efficiency of pollutants was about 0.85 and 0.48 mg/m3 per minute, respectively. This study was helpful to the improvement and optimization design of air quality and ventilation mode in trains.

Industrial hydraulic turbines, a kind of small-scaled turbine in a more compact and flexible application, are frequently used in hydrogen cracking, synthesis ammonia, and circulating water field. Besides the energy recovery efficiency, the working stability at variable speed situations is a critical issue, since its rotation speed changes with the flow parameters of the upstream. In this paper, a conventional turbine was numerically investigated under three different rotation speeds and its best efficiency points (BEPs). The velocity profiles, blade load, pressure fluctuation, and vibration features were discussed to form a comprehensive evaluation of turbine stability. The numerical results were validated through turbine external characteristic and vibration tests. The results indicate that the pressure pulsation and vibrations increase when it deviates from the rated rotation speed, but the relatively low flowrate point behaves better than the large point in the aspect of turbine stability, the main reasons are the angle of incidence and rotor circumferential vortex. The conclusions can provide significant reference for turbine hydraulic optimization and engineering application.

Nonthermal plasma has a great potential for the partial oxidation of gasoline to form cleaner fuels. However, the formation of deep oxidation products and cracking products makes plasma environmentally unfriendly. This paper reports the partial oxidation of simulated gasoline (n-C5H12) to syngas and oxygenated products. For this purpose, a dielectric barrier discharge reactor was used in which the background temperature and gas pressure could be individually controlled. We found that the conversion of n-C5H12 increased with increasing background temperature until 498 K, then reduced at 523 K because of the resistive loss of discharge power. In contrast, the selectivity of oxygenates and the H2/CO value monotonously decreased with increasing background temperature. It was inferred that the conversion of n-C5H12 depends on both the thermo-chemistry and the electron-induced chemistry, and their contribution to this process was almost the same at 498 K. In contrast, the mechanism of product formation was mainly controlled by thermo-chemistry. The benefits of using cold plasma to simultaneously produce syngas and oxygenates were highlighted. Our results may be used to develop a new concept for designing an environmentally friendly plasma reformer.

The opening unit is an important device in a rotor spinning unit to comb fibres and remove trash. In this paper, numerical simulation is carried out to study the flow structure in the rotor spinning channel and the trash removal process in the trash removal unit. Firstly the effect of the opening unit on the airflow field in the rotor channel is investigated by singlephase simulation. The result shows that the effective area for fibre conveyance enlarges as the absolute value of negative pressure at the outlet increases, while it decreases as the opening roller speed increases. However, the effect of the negative pressure and the opening roller speed on the length of the vortex in the axial direction is quite small. Secondly the trash separation process in the trash removal unit is simulated using the Discrete Phase Model (DPM). Suitable rotational speeds of particles of different diameters are acquired. These results could provide a valuable reference for parameter selection in the trash-removal process.

Air-jet loom is a kind of shuttleless loom, which is widely used in textile industries. The weft insertion system is composed of main nozzle, auxiliary nozzles, and profiled dent groove. The jets from the main and auxiliary nozzles intersect in the profiled dent groove. The velocity and stability of the intersecting airflows have a direct impact on the yarn’s motion. In this paper, the commercial software is adopted to simulate the intersecting airflows in the profiled dent groove. The result shows it is reasonable that the distance from the main nozzle to the first dent is 15 mm. The optimal distance from the main nozzle to the first auxiliary nozzle is between 45 and 50 mm based on the criteria of the utilization efficiency of the airflow. According to the standard of airflow stability, when the spray angle of auxiliary nozzle is about 7°, the standard deviation of the radical airflow velocity is the smallest in different cross sections. Therefore, the intersecting airflows are the most stable w...

An experimental platform is constructed to photograph fibers’ motion within rotor spinning unit, which is mainly composed of a transparent rotor and a transport channel based on the similarity theory. The fibers will stretch and gather into a fiber bundle in the transport channel. The velocity of fibers is increasing along the inlet to the outlet of the transport channel, and the fibers’ maximum velocity appears at the outlet of transport channel. The straightness of the fiber bundle is related to the convergence degree of the transport channel, and the greater the convergence degree is, the straighter the fiber bundle stretches. The results will provide a useful insight to the yarn-forming mechanism of rotor spinning.

In response to the risks of privacy leakage caused by uploading vehicle participants' sensing data (such as location data or task sensing data) in the vehicle crowdsensing environment, an improved DBSCAN Clustering Algorithm (I-DP-DBScan) is proposed in the paper. The proposed algorithm is improved by optimizing the parameters Eps and MinPts, and differential privacy is adopted for guaranteeing participants' privacy. Laplace noise is added to the Euclidean distance of sensing data. Experimental results show that the I-DP-DBScan algorithm not only protects data privacy but also has good clustering efficiency.

A three-dimensional numerical study of a single droplet splashing vertically on a liquid film is presented. The numerical method is based on the finite volume method (FVM) of Navier–Stokes equations coupled with the volume of fluid (VOF) method, and the adaptive local mesh refinement technology is adopted. It enables the liquid–gas interface to be tracked more accurately, and to be less computationally expensive. The relationship between the diameter of the free rim, the height of the crown with different numbers of collision Weber, and the thickness of the liquid film is explored. The results indicate that the crown height increases as the Weber number increases, and the diameter of the crown rim is inversely proportional to the collision Weber number. It can also be concluded that the dimensionless height of the crown decreases with the increase in the thickness of the dimensionless liquid film, which has little effect on the diameter of the crown rim during its growth.

The dynamics of an elastic fiber with various initial states in a laminar channel flow is investigated using the immersed boundary-lattice Boltzmann method. Fiber-wall collisions are solved by adding a repulsive force in the model. Our simulation results demonstrate that the initial fiber state closely relates to the stability of the considered conveyance system. Different initial states may lead to different dynamic patterns in the downstream. The fiber is found to go straight forward along a horizontal path when it is horizontally and symmetrically placed at the channel centerline. Breaking this symmetry by varying the fiber's initial vertical position or orientation will induce the instability of the system, which then causes deviations and fluctuations in fiber's conveyance path. No matter how large the deviation occurs in the upstream, the fiber is always found to migrate to the channel central region in the downstream and would eventually settle in a vertical position slightly away from the channel centerline. Moreover, the off-centerline distance that a fiber settles depends on its dynamic pattern rather than a specific initial fiber state. For our system, there are two kinds of dynamic patterns observed in the downstream channel. In the first pattern, the fiber eventually reaches its equilibrium state and is observed to do a translational motion. In the second pattern, no equilibrium state is observable, and the fiber is found to do a periodically tumbling motion. The fiber's eventual conveyance speed depends on the vertical position it eventually settles and can be roughly approximated by the local flow velocity.

In this study, we investigated the effects of chain length and degree of unsaturation of fatty acid (FA) on the structure, physicochemical properties, and in vitro digestibility of maize starch (MS)–FA complexes. Differential scanning calorimetry, X-ray diffraction, and Raman spectroscopy revealed that crystalline structure with V-type was formed between MS and FA. Nuclear magnetic resonance spectroscopy confirmed that the complexes with various FA structures displayed different V-type polymorphs. The thermal stability of the complexes with 14-carbon and 16-carbon FAs was better than that of other complexes. The complexes with 12-carbon (21.77%) and 14-carbon (26.31%) FAs displayed high resistant starch (RS) content, whereas those with 10-carbon FAs exhibited high slowly digestible starch (SDS) content (28.99%). Additionally, the FAs with a chain length of 10–14 carbons produced more ordered structures and showed stronger intermolecular interactions with MS than other FAs. For the 18-carbon FAs, the complexes with unsaturated FAs displayed higher RS and SDS content than those with saturated FAs. Moreover, the unsaturated FAs showed stronger intermolecular interactions with MS than the saturated FAs. These results indicated that FA structures significantly affected the structures of complexes, further affecting their physicochemical and digestive properties.

Rotor spinning is an open-end spinning method that uses air as the medium to transform the fibers into yarn. Nowadays, the properties of its final product—yarn—such as yarn strength and yarn twist, are not satisfied due to the fiber morphology, which greatly depends on the distribution of the massive fibers in the rotor spinning unit (RSU). In this paper, theoretical analysis is given to describe the trajectory of fiber on the slide wall. A numerical study is performed with the massive fibers being simplified into granules to study their distribution characteristics in the RSU. According to our numerical results, the forming process of the fibrous ring is discussed and the effects of two variables, the rotor speed and the angle of the slide wall, on the distribution of fiber granules were also studied. The simulation results indicate that the fiber granules are not evenly distributed during their transport in the fiber transport channel (FTC) and they tend to accumulate on the upper and lower edge of the FTC. The distribution of fiber granules in the groove (fibrous rings) is closely related to the rotor speed. The higher the rotor speed, the longer and thinner the fibrous ring. The distribution of fiber granules on the slide wall is related to the angle of the slide wall such that a smaller angle leads to a scattered distribution on the slide wall, while a larger angle tends to bring a concentrated one. The simulation results show good agreements with our experimental results.

The air-jet loom is widely used in the textile industry. The interaction mechanism of airflow and yarn is not clear in such a narrow flow channel, the gas consumption is relatively large, the yarn motion is unstable and the weft insertion is often interrupted during the operation. In order to study the characteristics of the semi-closed flow field in profiled dents, the momentum conservation equation is modified and the model parameters and boundary conditions are set. Compared with the different r, the ratio of profiled dent’s thickness and gap, the results show that the smaller the r is, the smaller the velocity fluctuations of the airflow is. When the angle of profiled dents α is close to zero, the diffusion of the airflow will be less. The experiment is also conducted to verify the result of the simulation with a high-speed camera and pressure sensor in profiled dents. The airflow characteristics in the semi-closed irregular narrow flow channel in the paper would provide the theoretical basis for optimizing the weft insertion process of the air-jet loom.

The cancer area segmentation of esophageal histopathology images is a crucial step in determining the stage of esophageal cancer. This task is very important. However, manual segmentation will cost a lot of time. The rise of computational pathology has led to the development of automatic methods for cancer area detection. In the automatic segmentation problem, a well-labeled dataset is the most important part. One of the main contributions of this paper is to establish a dataset contains 1388 patches (958 Normal and 430 Abnormal containing tumor cells), marked with cancer, all of which are manually labeled and supervised by professional pathologists. We test the currently popular networks on our dataset, such as DeeplabV3, FCN+ResNet, Unet and so on. And FCN+ResNet achieves the best performance on our dataset with the highest Mean IoU (85.06%) and Pixel Acc (92.63%).