l. zhang

To enhance the firefighting capabilities of traditional dry powder extinguishers, we incorporated an air-assisted supersonic nozzle, which is simulated using Euler-Lagrange interphase coupling to simulate the injection of firefighting agents into a supersonic, two-dimensional axisymmetric gas flow from a bypass injector. During the simulation, we employed our newly developed modified drag coefficient model, capable of accommodating a broad spectrum of particle Reynolds and Mach number conditions. Parameter studies show that an increase in the injector position, angle, and total pressure ratio generally causes a decrease in the average particle velocity vp,a, and an increase in the dispersion Ψp and velocity unevenness Φvp; an increase in the total pressure ratio of the main nozzle leads to an increase in Φvp and vp,a. However, under specific conditions, the monotonic dependency upon these parameters may be disrupted. For example, the performance indicators at the position of the injector near the nozzle throat and a larger total injector pressure ratio, as well as vp,a at smaller injection angles and Ψp at larger injection angles, may run counter to the monotonicity.

The water-entry process of solid and hollow hyperelastic spheres was numerically simulated using the arbitrary Lagrange–Euler method, based on the finite element analysis software LS-DYNA. The effect of the different initial velocities on the cavity evolution and deformation of the sphere in a range of low Froude (Fr) numbers was investigated. The evolution of the cavity, deformation of the hyperelastic sphere and parameters at the time of cavity closure were analysed. In addition, the difference in the water-entry process between solid and hollow spheres was given. The numerical results shows that the size of the cavity, fluctuation on the cavity profile, closure time and closure depth increased with Fr and that the closure time was proportional to Fr1/2 for both solid and hollow spheres. However, the relationship between the closure depth and Fr of the hollow sphere differed from that of the solid one. Within the investigated low Froude numbers, whether for the solid or hollow spheres, the deformation amplitude increased with the Froude number. However, the deformation period remained nearly the same for different conditions. Under the same physical and motion parameters, the hollow sphere exhibited larger deformations compared with the solid sphere. The deformation period for the hollow sphere was also longer than that for the solid one.

Since the constant power loads (CPLs) have negative-impedance characteristics, the system damping of DC microgrid is reduced, which will lead to the collapse of bus voltage. In addition, the errors of current sharing within parallel-connected DC-DC converters amplify due to different line impedances. To address these issues, a hybrid coordination control strategy is proposed for parallel-connected boost converters, which realizes the stable control and maintains the accuracy of current distribution. Firstly, a passivity-based control (PBC) with a proportional-integral (PI) regulator is developed for the boost converter with CPL. The virtual damping based PBC enhances the system damping and PI regulator eliminates the steady-state error caused by the variation of load. On this basis, a secondary voltage control (SVC) featuring in simplicity and weak dependence on communication is introduced to remove the errors of current distribution. Finally, a RT-LAB-based hardware in the loop (HIL) experimental platform is established and the experimental results verify the effectiveness of the proposed hybrid coordination control strategy.

To investigate the value of 3.0T magnetic resonance perfusion-weighted imaging (PWI) in the preoperative differential diagnosis and grading assessment of gliomas. The PWI features of 23 single brain metastases and 73 gliomas (32 low-grade and 41 high-grade) were retrospectively analyzed with postoperative pathological findings. The cerebral blood volume (CBV) values of the tumour parenchyma, the peritumoral oedema area and the contralateral normal brain tissue were measured, and the relative CBV (rCBV) values were calculated and statistically analysed. A total of 96 patients, comprising 66 men and 30 women with a mean age of 47 ± 11 years, were included in the study. The time-signal curves of gliomas of different grades obtained by magnetic resonance perfusion have different characteristics. The rCBV values for tumor parenchyma and peritumoral edema were higher in the high-grade glioma group than in the low-grade glioma group and the single brain metastasis group ([6.01 ± 1.64] vs [2.16 ± 0.87] vs [4.37 ± 1.03]) and ([1.82 ± 0.47] vs [0.79 ± 0.34] vs [0.81 ± 0.21]), and the differences were significant (p < 0.05). The rCBV value of the tumour parenchyma in the single brain metastasis group was higher than that in the low-grade glioma group ([4.37 ± 1.03] vs [2.16 ± 0.87]), and the difference was significant (p < 0.05). Magnetic resonance PWI has high clinical value in the preoperative diagnosis and grading evaluation of gliomas.

While neonatal pneumothorax (NP) is uncommon, it presents a serious condition requiring immediate and precise diagnosis and treatment. To achieve this, dependence on imaging techniques is crucial for detecting gas accumulation within the infant's thoracic cavity. Traditionally, diagnosing NP relies heavily on Chest X-ray (CXR) examinations, involving ionizing radiation exposure, a persisting concern. Conversely, lung ultrasonography (LUS) has gained widespread recognition due to its convenience, expediency, and radiation-free attributes. The debate over whether LUS can completely replace traditional CXR remains contentious. Our objective is to conduct a thorough analysis of the efficacy of LUS and CXR examinations in diagnosing NP, with the intention of offering additional references for clinicians to optimize medical care for infants, minimizing radiation exposure and ensuring comprehensive protection of their health and safety.

In this study, we aim to examine the influence of water entry velocity of a single and two tandem projectile(s) on the supercavitation flow and projectile loading under wave conditions using numerical simulation. The volume of fluid model, renormalization group (RNG) κ-ε turbulence model, and Schnerr–Sauer cavitation model are adopted to simulate the multiphase, turbulent, and cavitation flow, respectively. The projectile movement is considered using overlapping grids and a six-degree-of-freedom model. The results show that as the projectile velocity increases, both the dimensionless maximum radius and length of the cavity, as well as the yaw angle, also increase with the rising water entry velocity. For the two tandem projectiles, the cavity pattern on the second projectile varies as the projectile velocity changes. With a lower projectile velocity, the second projectile cannot directly access the front cavity, and there may be situations wherein the part of the second projectile is not enveloped by cavity. As the projectile velocity increases, the second one can directly enter the cavity of the first projectile without forming a separate cavity around itself. In all of the examined cases, the peak pressure on the first projectile is approximately an order of magnitude higher than that on the second one. Furthermore, with increasing projectile velocity, the pressure peak ratio between the first and second projectiles increases.

We aimed to analyze the value of volume rendering (VR) in diagnosing different solitary pulmonary nodules (SPNs) with diameter less than 1.0 cm and assessing invasion depth in lung adenocarcinoma.

In total, 908 patients with SPN that was confirmed by postoperative pathology were included, followed by an analysis of the imaging characteristics (including microvascular sign, vascular convergence, lobulation, and spiculation) of malignant and benign SPN based on VR. Moreover, the detection rates of imaging signs of three types of malignant SPNs (pure ground grass nodule, pGGN; part-solid nodule; and solid nodule) classified by SPN density and three invasion depths of adenocarcinoma (pre-invasion lesion, PIL; micro invasive adenocarcinoma, MIA; and invasive adenocarcinoma, IAC) were also analyzed.

The microvascular sign detection rate was higher while vascular convergence and spiculation detection rates were lower in malignant SPN than in benign SPN. The microvascular sign possessed high sensitivity (82%) and specificity (72%) in predicting malignant and benign SPNs. The microvascular sign detection rate decreased while vascular convergence, lobulation, and spiculation detection increased with the rising density of malignant SPN. Furthermore, the detection rates of the four imaging signs all increased with the adenocarcinoma invasion depth. Microvascular sign showed good detecting ability in low density SPNs pGGN (81.8%), part-solid nodules (95.8%), and in all three invasion depths of adenocarcinoma (PIL [68.2%], MIS [95.3%], and IAC [87.2%]).

These imaging features distinguished by VR exhibited an excellent differential diagnostic ability of various SPNs as well as invasion depth of lung adenocarcinoma.

It is essential to maintain the aerodynamic performance of the air-conditioning system meanwhile reducing the noises (including aerodynamic, broadband, and discrete noises), determining the consumer's comfort level. In this work, depending on the coupling of the wavy leading-edge and the seagull airfoil, the aeroacoustics noise and aerodynamic performance of the impellers with the coupling bionic blade were investigated in detail. The results indicate the aerodynamic performance was improved by the coupling bionic optimization. Moreover, the total pressure efficiency (η) of the coupling bionic blade increases by 2.28% in comparison to the original blade. Furthermore, A smaller static differential pressure is observed between the suction and pressure sides, and vortices and backflows from the pressure side to the suction side are hampered, causing a reduction in turbulence noise. Additionally, the broadband noise of the coupling bionic blade decreases by 3.59 dB. Besides, the coupling bionic blade improves the directivity of the sound pressure level, especially in the middle-frequency and low-frequency region, resulting in a decrease of 7.9 dB for the aeroacoustics noise of the coupling bionic blade. What's more, the modal analysis demonstrates the security of the designed coupling bionic blade. In generally, this work provides some inspiration to design axial flow fans with excellent aerodynamic performance and low-noise characteristics.

This study aimed to evaluate the relationship of tumor size and ultrasound (US) Breast Imaging Reporting and Data System (BI-RADS), and further analyze if tumor size can impact the evaluation for US features in patients with breast cancer.

In this retrospective study, preoperative US features and postoperative pathological results were collected from 498 patients with breast cancer. The association of BI-RADS classification with tumor size was analyzed, and the US features related to tumor size were determined.

A significant association was found between tumor size and BI-RADS category, and tumor with small size was classified into the low BI-RADS category (p < 0.05). Some US features including shape, growth orientation, microcalcification and color Doppler flow imaging (CDFI) were influenced by tumor size (p<0.001).

Tumor size can influence the diagnosis performance for US BI-RADS category in patients with breast cancer.

On account of the idea of maximum fuzzy entropy and  symmetric implicational mechanism under the environment of intuitionistic fuzzy sets,  we come up with the intuitionistic fuzzy entropy derived symmetric implicational (IFESI) algorithm.  Above all, novel symmetric implicational principles are presented, and the unified solutions of the IFESI algorithm are  acquired for IFMP (intuitionistic fuzzy modus ponens) and IFMT (intuitionistic fuzzy modus ponens), which build upon in view of residual intuitionistic implications. Thereafter, the reductive properties and continuity of the  IFESI algorithm are validated for IFMP and IFMT. In addition, the IFESI algorithm is extended to the $alpha$-IFESI algorithm, and the unified solutions of the $alpha$-IFESI algorithm are obtained for IFMP and IFMT. Finally, two examples of fuzzy classification for the $alpha$-IFESI algorithm are presented to demonstrate the detailed computing process of the IFESI algorithm.

Aggregation of fluidization media may appear at the dense phase region of the pant-leg fluidized bed near the incline walls. When the particles flow along the inclined wall, the friction and drag force will cause the particles to accumulate on the inclined wall, resulting in an uneven distribution of particles. The stagnant zones can be minimized by correctly arranging secondary air. Computational particle fluid dynamics (CPFD) method was used to simulate the gas-solid two-phase flow pattern in the dense phase region of pant-leg fluidized bed. Cold tests were performed on a benchtop pant-leg fluidized bed. A high speed imaging technology was used to monitor the flow pattern in the dense phase area, whereas the bubble size and residence time were compared to verify the accuracy of the simulation. The gas-solid flow patterns under various models were simulated. The influence of different secondary air velocities on the reduction of stagnant zone in the dense phase zone of the fluidized bed were predicted. The results indicated that the introduction of secondary air could effectively promote the mixing of particles, and weaken the accumulation of particles on the inclined wall surface. Moreover, secondary air can effectively promote the flow between the gas-solid two-phases and improve the combustion characteristics in the furnace.

Lycium barbarum is a traditional Chinese medicine. Its pharmacological effects mainly rely on a component called Lycium barbarum polysaccharide (LBP). The present study aims to explore the mechanism by which LBP reduces radiation damage in X-ray-irradiated cultured mouse bone marrow mononuclear cells （BMNCs） and the potential involvement of apoptosis.

Mouse BMNCs were cultured in vitro and exposed to radiation. After 24 hours of LBP treatment, BMNCs viability was detected by cck-8 method, apoptosis rate was examined by Flow cytometry (FCM), Mitochondrial membrane potential (MMP) fluorescence was detected by JC-1, and the expression of mitochondrial pathway-associated protein was measured by immunoblotting.

LBP significantly increased BMNCs viability and reduced the apoptosis rate of radiation-exposed BMNCs 24 h after treatment compared to the non-treated control group. In a mitochondrial membrane potential fluorescence assay, LBP reduced the radiation-induced decrease in mitochondrial membrane potential. Western blot analysis further proved this point, where LBP inhibited the release of cytochrome C from mitochondria and also inhibited the expression of caspase 9 and other mitochondrial-related proteins.

The mechanism of LBP action in radiation-exposed mouse BMNCs cells seems to involve inhibition of the mitochondrial apoptosis pathway.

The lattice Boltzmann models, especially the pseudopotential models, have been developed to investigate multicomponent multiphase fluids in presence of phase change process. However, the interparticle force between different components causes compressibility error in the non-phase-change component. This restricts the model capability in quantitative analysis of the physical foaming process, such as expansion rate and decay time. In the present study, a multicomponent multiphase pseudopotential phase change model (the MMPPCM) is improved by introducing an effective mass form of high-pressure-difference multicomponent model in the non-phase-change component. The improved model is compared with the MMPPCM based on simulations of the phase change process of static and moving fluids, as well as the physical foaming process. Density variation of non-phase-change component and its effect on flow field characteristics are analyzed during the phase change process. Simulation results of physical foaming process lead to about 10% ~ 20% reduction of the compressibility error for the improved model as compared with the results of MMPPCM. The improved model also enhances the computational stability of phase change simulation of the static droplets.

The head shape of a high-speed maglev train was optimized in this study, based on the adjoint method, and the aerodynamic drag of four optimized train models were simulated and compared using different control point generation methods. The effectiveness of using the adjoint method to develop a compressible model for a maglev train was verified. The results show that the adjoint matrix optimization method can quickly and effectively capture the shape characteristics of the train head that are sensitive to aerodynamic resistance. When the design variables of the head are not defined separately, the grid control point set and surface control point set can be used to carry out the adjoint closed-loop optimization of the train head shape, and the exchange control point generation method can be used to perform closed-loop optimization. The results of a numerical simulation show that the optimized train model reduces aerodynamic resistance by approximately 4.8%.

The branch baffle heat exchanger, being an improved shell-and-tube heat exchanger, for which the flow manner of the shell-side fluid is a mixed flow of oblique flow and local jet. The computational fluid dynamics (CFD) method has been implemented to investigate the fluid pattern and heat transfer performance. The accuracy of the modeling approach has been confirmed by an experimental approach using a Laser Doppler Velocimeter system. Flow field, temperature field, and pressure field are displayed to study the physics behavior of fluid flow and thermal transport. Heat transfer coefficient, pressure drop, and efficiency evaluation criteria are analyzed. In contrast with the shell-and-tube heat exchanger with segmental baffles and shutter baffles, the pressure loss in the proposed heat exchanger with branch baffles has been dramatically improved, accompanied by a slight decrease in heat transfer coefficient under the same volume flow rate. The efficiency evaluation criteria of the heat exchanger with branch baffles are 28%-31%,13.2%-14.1% higher than those with segmental baffles and shutter baffles, respectively. Further analysis in accordance with the field synergy principle illustrates that the velocity and pressure gradients of the heat exchanger with branch baffle have finer field coordination. The current heat exchanger structure provides a reference for the future optimization design to reach energy saving and emission reduction.

Ratoon Rice (RR) has been proposed to be an effective alternative rice system to increase productivity growth and reduce the environmental impact, but data on the economic performance of RR for farmers are limited. A survey of paddy farms was conducted to assess the impact of the adoption of RR in Hubei, China. Endogenous switching regression framework was used to account for observed and unobserved heterogeneity. We analyzed the effect of yield, income, and technical efficiency of RR adoption. Results show that adoption of RR has great impact on yield, income, and technical efficiency. Increase in rice yield (by 5.12%) and rice income (3.74%) was found for RR farmers; increases of yield, income and technical efficiency was also significant if farmers cultivating single rice shifted to RR. Technical efficiency showed a large difference when RR was adopted by farmers cultivating single rice. Small farms and large farms benefit from the adoption of RR. Large farms benefit more yield and income than small farmer, while small farms are more efficient than large farms. Our findings provide meaningful and timely implications for future national programs and policies to promote the implementation of RR in China that aim to promote more sustainable practices and lower environmental impact in agriculture.

This study was conducted to evaluate the control efficacy of Pseudomonas chlororaphis, Erwinia herbicola, Bacillus amyloliquefaciens, and Bacillus subtilis, as well as solutions of zinc sulfate, sodium malonate, and oxalic acid against potato white mold caused by Sclerotinia sclerotiorum under field conditions during growing seasons of 2017 and 2018 in Bahar and Lalehjin, Hamedan, Iran. The results showed that strains of Bacillus subtilis as well as zinc sulfate had the highest inhibitory effect against carpogenic germination of sclerotia. The myceliogenic germination of sclerotia was inhibited by solutions of zinc sulfate and sodium malonate with statistically similar results followed by oxalic acid. In addition, activities of resistance-related enzymes including β-N-acetyl hexosaminidase, endochitinase, chitin 1,4-β-chitobiosidase, β-1,3-glucanase, phenylalanine ammonia lyase, polyphenoloxidase, and peroxidase markedly increased in potato leaves due to application of bacteria on plants. The results showed that all treatments were able to reduce significantly (P< 0.05) the number of infected and dead plants in both years. The mixtures of five bacterial biocontrol agents and solution of zinc sulfate were found to be the most effective treatments to control white mold.

Window glass of the train was broken several times when running in the strong wind/sandy areas, causing safety risks to passengers and serious problems to the operation of the train. The aerodynamic performances of the train with broken windows in strong wind condition are uncertain. These problems remain the challenging research issues. To study these issues, the influence of the broken windows on the aerodynamic performances of the train model was analyzed using three-dimensional numerical simulation methods. The results showed that the aerodynamic forces on the second passenger car first decreased and then increased within a very short period when the two middle windows on the windward side had been broken. However, the side force and the overturning moment increased sharply when the wind angle was increasing. In addition, the number of broken window glass has significant effects on train aerodynamics when running in cross wind area, and the absolute value of the side force and of the overturning moment increased significantly with the increase in the number of broken windows on windward side.

Onsite utilization of wind energy in the urban environment is an effective solution to environmental protection and energy security. The typically micro wind turbines, including Savonius vertical axis wind turbine, H-type vertical axis wind turbine and micro horizontal axis wind turbine are more suitable for distributed generation, relative to centralized generation of large scale wind turbines. However, the wind in the urban environment characterized by low wind speed, high levels of turbulence and strongly unsteady direction and speed, directly affecting the aerodynamic characteristics of wind turbine. In the present work, wind tunnel tests have been conducted to investigate the low Reynolds number effect on aerodynamic characteristics for these three typical micro wind turbines, and the aerodynamic differences among them have been compared qualitatively and quantitatively. The experimental results show that micro horizontal axis wind turbine and H-type vertical axis wind turbine, belonging to lift-type wind turbine, have relatively higher startup wind speed and lower power coefficient due to deteriorative aerodynamic performance of airfoil at low wind speed. However, Savonius vertical axis wind turbine, as a drag-type wind turbine, exhibits excellent aerodynamic performance at low Reynolds number. The Savonius wind turbine has apparent output power at 5m/s, and the peak power coefficient exceeding 0.2 at 9m/s being superior to that of two other lift-type wind turbines at the same wind speed. In addition, in consideration of natural advantage of vertical axis wind turbine, Savonius wind turbine is the best option for applying at low Reynolds number urban environment.

Salmonella can cause serious human gastroenteritis and is frequently isolated from various food samples. The cell culturing, immunoassay, and polymerase chain reactions (PCR) are the current methods to detect such pathogenic agents. However, these methods are time-consuming and labor-intensive, and thus unavailable for rapid-monitoring of Salmonella.

This study aimed to develop an immunocapture-loop-mediated isothermal amplification (IC-LAMP) for rapid and sensitive detection of Salmonella.

Salmonella was used as antigen to produce monoclonal antibody (mAb) and mAbs were prepared via subcloning three times. The mAb 1B12 with high affinity was coated on the surface of the immuno-magnetic beads (IMBs) to capture Salmonella. The enriched products (IMBs-Salmonella) were used for LAMP using the special primers targeted the conserved invA gene of Salmonella.

The IC-LAMP was developed based on mAb 1B12 and LAMP. Targeting the conserved invA gene of Salmonella, the detection time was shortened to 50 min from three days. If the reaction contains Salmonella, the green fluorescence and the trapezoidal strip can be clearly observed. Importantly, the method combines the specificity of antibody and LAMP with a detection limit of 5 CFU/ml in artificially contaminated water and milk. The specificity of this method was demonstrated by testing other similar bacteria. The results indicate that the IC-LAMP reacts only with Salmonella and does not cross-react with other similar bacteria.

The IC-LAMP assay developed here is a rapid, sensitive, one-step-visual method to screen for the presence of Salmonella in food samples. This method is faster than traditional PCR, LAMP, and other methods, and can be used as a primary screening method for the detection.