q. liu

The complex transient flow field in the entire hydraulic system of a large pump turbine under load rejection conditions, involving the simultaneous closing of the ball valve and guide vanes, is comprehensively investigated using the Re-Normalization Group (RNG)k-e model and Fast Fourier Transform (FFT) technique. The predicted pressures at the volute inlet and guide vane outlet show good agreement with the field test data, with corresponding relative errors of 0.87% and 0.33%, respectively, between the predicted maximum pressures and those measured in the field. The main frequencies of pressure at the volute inlet are the unit rotating frequency during the initial time stages (0–3s), and low-frequency fluctuations in the later stages (3–8s and 8–11s). In contrast, the corresponding frequencies at the guide vane outlet are consistent with the blade frequency. During the ball valve closing process, as the unit rotational speed increases, complex flow separations cause vortices near the middle of the runner to coalesce into two large vortices of similar size. Meanwhile, the cross-sectional area of the vortex rope in the draft tube increases, and its spiral shape becomes increasingly irregular until it breaks apart. Based on the Q criterion, a series of 3D complex vortices form inside and downstream of the ball valve at the onset of the combined closing stage, intensifying as the guide vanes close. A spiral-shaped vortex rope in the draft tube extends downstream, breaking into smaller vortices after passing through the draft tube elbow, with the location of the fracture moving upstream as the flow rate decreases further.

Pulmonary artery intimal sarcoma (PAIS), a rare malignancy arising primarily within the pulmonary artery's intimal layer, exhibits an estimated prevalence ranging from 0.001% to 0.003%. Due to overlapping clinical manifestations and imaging characteristics, PAIS is frequently mistaken for acute or chronic pulmonary thromboembolism. Tissue biopsy remains the authoritative method for establishing diagnosis. Regarding therapy, surgery is the principal approach, and undertaking thorough surgical resection alongside endarterectomy yields improved survival outcomes.

This study presents three cases of PAIS, analyzing their radiological characteristics, pathological findings, and therapeutic approaches. A comprehensive review of the literature on this condition is also provided.

Timely detection proves paramount and can significantly enhance patient prognosis. Complete surgical resection is pivotal for improving prognosis, and multidisciplinary collaboration (e.g., radiology, pathology, and thoracic surgery) plays a vital role in formulating precise diagnostic and therapeutic strategies.

Surface roughness of ski suits can have a significant effect on the aerodynamic performance of ski jumping athletes. Herein, several typical surface roughness configurations are examined through numerical simulations. Force parameters such as lift, drag and pitching moment are analyzed to evaluate the aerodynamic performance of varying surface roughness. Furthermore, the athlete model is segmented into distinct body parts to conduct a comprehensive analysis of the aerodynamic contributions from each individual segment. Generally, the surface roughness has a significant effect on the aerodynamic performance during the flight phase. Specifically, the lift-drag ratio of the entire multibody system shows a trend of increasing first and then decreasing. Moreover, the trunk of the athlete plays a predominant role in generating aerodynamic forces during the flight phase. Therefore, when designing high-performance ski jumping suits, prioritizing the surface roughness of this part can be considered first. Flow structures are also presented to analyze the impact of these various surface roughness conditions. Notably, flow suppression near the back region of the athlete body can significantly reduce the resistance force in the horizontal direction. Consequently, this revelation of the impact mechanism of ski suit surface roughness on the aerodynamic performance of the multibody system can guide the design of appropriate ski suits, and will also assist athletes in achieving superior aerodynamic performance during flight.

The issue of pedestrian-level wind environments around high-rise buildings is closely related to the comfort and safety of human settlements. In this paper, we study the effects of different wind direction angles and spacing ratios on the wind environment at pedestrian heights around buildings arranged in an equilateral triangle configuration. Three-dimensional steady-state numerical simulation was employed, with the standard k-ε model selected as the turbulence model. Wind speed ratios and different area ratio parameters are used to quantitatively express the degree and range of influence of wind speed by buildings. The results show that the maximum wind speed ratio at the corner of a building is greatly affected by the wind direction angle, with 45°, 135°, and 157.5° being the unfavorable wind direction angles. Conversely, the area ratio of different areas is greatly affected by the spacing ratio. As the spacing ratio increases, the mutual interference effect between buildings weakens, resulting in a better pedestrian wind environment. Owing to the unique layout of the building group, different degrees of ventilation corridors are formed among the three buildings. The wind speed amplification effect in the corridors is more significant, and the areas with poor wind environments are concentrated in these corridors.

The sport of half-pipe skiing, characterized by its dynamic maneuvers and high-speed descents, often faces challenges posed by unpredictable wind conditions.  To address this, an advanced wind-blocking system incorporating an air curtain capable of generating a jet flow is proposed. This pioneering design offers a dual advantage: the system can significantly reduce the windbreak size in the vertical dimension while maintaining a satisfactory wind-blocking effect. A comprehensive study is conducted to analyze the effects of the height of the windbreak and the jet emission angle from the air curtain. When the jet speed is 40 m/s, a 50° emission angle and a 2 m height of the windbreak result in an optimal wind-blocking effect. Furthermore, delving deeper to understand the underpinnings of this phenomenon, we discovered that a counterrotating vortex pair, which forms in the presence of this jet under crossflow conditions, plays a pivotal role in augmenting the wind-blocking capabilities of the system.

An oscillating water column (OWC) is typical of axial rotor turbines, which are used to convert ocean wave energy into electrical energy. This device impacts downstream pressure pulsations when its rotor becomes eccentric. This study compared the details of pressure pulsations downstream of eccentric and non-eccentric rotors under three operating conditions: low flow A, high-efficiency flow B, and high flow C. Computational fluid dynamics (CFD) simulations based on the pulsation tracking network (PTN) method were used for the OWC device to compare the experimental results. The results indicate downstream pressure pulsations were mostly dominated by the blade frequency in non-eccentric low-flow cases. In the other eccentric operating conditions, downstream pressure pulsations were mainly dominated by the 2-, 3.6-, 6-, and 7-times rotation frequencies and the 0.5-times blade frequency. The phase change of downstream pressure pulsations in eccentric and non-eccentric conditions is consistent with the flow direction. The phase change is relatively uniform and steady before eccentricity and becomes turbulent after eccentricity, which affects its steadiness. In this study, the OWC device did not significantly change with or without rotor eccentricity at a 1-time blade frequency intensity; however, at a 1-time rotation frequency, the OWC device showed a significant increase in the pressure pulsation amplitude after rotor eccentricity. The study of the dominant frequency, amplitude, and phase of pressure pulsations in OWC devices with eccentric rotors can help prevent excessive pressure pulsations that can lead to incidents.

Pulmonary Aspergillus has a high incidence and mortality rate, but is difficult to be diagnosed. It is mainly caused by Aspergillus fumigatus. Pulmonary Aspergillus caused by Aspergillus oryzae is rare. This case reports an 8-year-old male patient with acute lymphoblastic leukemia (ALL) who was found to have pulmonary Aspergillus oryzae infection by NGS of alveolar lavage fluid.

Case Summary: 

The patient had ALL and received induction remission chemotherapy. During chemotherapy, the patient developed severe agranulocytosis and severe pneumonia. The treatment was performed accordingly. The second-generation sequencing of alveolar lavage fluid identified the pathogen as Aspergillus oryzae. After combined antifungal treatment with caspofungin and voriconazole, pneumonia was absorbed and improved. One week later, spontaneous fluid pneumothorax accompanied by massive hemoptysis occurred, and the patient received rescue therapy, which was successful. Finally, the patient recovered after pulmonary lobectomy and purulent moss stripping.

Early diagnosis and treatment of pulmonary Aspergillosis are very important. Aspergillus oryzae infection has only rarely been reported in humans. Second-generation sequencing of alveolar lavage fluid is an accurate and effective detection method to assist diagnosis of microorganism infection. Combination of caspofungin and voriconazole is an effective method to treat severe Aspergillus pneumonia.

Wind loads of high-rise buildings are a key parameter in architectural design. The magnitude and distribution characteristics of wind loads are of great importance for the safety and economy of structural design. The wind loads of high-rise buildings are quite different from those of monomer buildings. The wind-induced interference effect could significantly increase the local wind pressure of buildings, causing potential safety hazards for the main structure and enclosure structure. For the three common high-rise buildings, we adopted the wind tunnel test method to measure the surface pressure of each building. The corresponding Re number was 8.2×106. This paper studied the shape coefficients, fluctuating wind pressure coefficients and base bending moment coefficient of each building with different wind direction angles and different spacing ratios, and the maximum value of each parameter and the corresponding working condition were statistically analyzed. The results showed that, under any wind direction angle, the fluctuating wind pressure coefficients on all sides of the building were affected by the spacing ratio, and the fluctuation range was large. When the wind angle was 180º, the fluctuating wind pressure coefficients on the sides of Building 1 were most affected by the slope ratio. At this wind angle, the maximum value was 0.43 at a slope ratio of 5.0, which was 65% different from the minimum. Partition shape coefficients of some sides and top surfaces changed significantly with the spacing ratio. When the spacing ratio was 5.0, the base bending moment coefficients in the downwind and crosswind directions reached their maximum values, and the wind direction angles where the maximum values of the base bending moment coefficients in the downwind direction were 40º and 50º, respectively, and the wind direction angle where the maximum value of the base bending moment coefficients in the crosswind direction was 10º. Due to the influence of the wind angle and the building spacing ratio, the wind loads on the facades of the pyramidal group of buildings varied greatly, and the wind-induced interference effect was evident. The wind load between the building facades in the three buildings was different, and the wind disturbance effect was evident. Therefore, the most unfavorable stress state and interference state of the structure should be comprehensively considered in the wind resistance design of the three buildings. The building spacing ratio should preferably be set to 3.0, and wind angles of 10º, 40º, and 50º should be avoided whenever possible.

In the Internet of Everything era, the Energy Internet of Things (IoT), as a typical application of IoT technology, has been extensively studied. Meanwhile, blockchain technology and energy IoT can be coordinated and complementary. The energy IoT is diversified and has a high transaction demand. it is an issue worthy of research to discuss the impact of the energy IoT environment on the performance of blockchain consensus algorithms and guarantee blockchain stability in energy IoT environment. In the research, an incentive mechanism based on Stackelberg game is proposed for the network scenario involving multiple roadside units and user nodes. The proposed strategy is analyzed through the Matlab simulation platform. The simulation results show that the proposed scheme can effectively protect the interests of blockchain users and miners. It also can improve the security and stability of the blockchain-based energy IoT system. Moreover, the numerical results not only verify the model feasibility. It also shows that when there are many blockchain miners, the model performance is fine. However, when the number of miners reaches a certain value, there will be unobvious growth. Furthermore, it is also confirmed that the wireless energy IoT environment will also create a certain impact on the game model.

Semi-open centrifugal pump has the disadvantage of low efficiency in chemical industry for its unique structure. For the purpose of improving its efficiency as much as possible on the premise of meeting the head demand, in this case, an optimization strategy combining Bezier curve, Genetic Algorithm (GA), Fuzzy Logic (FL), Artificial Neural Network (ANN) and solution space model based on stratified sampling is proposed to optimize the efficiency of semi-open centrifugal pump. The fourth-order Bezier curve is used as parametric method to control the blade profile, GA combined with FL is used as optimization strategy to seek the optimal individual. Besides, the optimization solution space based on stratified sampling method and ANN training are used to shorten computing time. Finally, the semi-open centrifugal pump corresponding to the optimal parameter combination of blade profile has been found, and on the premise of meeting the head requirements, the efficiency has been significantly improved. Entropy production rate is carried out to analyze the reason of efficiency improvement. The whole optimization strategy proposed in this study provides a good reference for parametric control and performance optimization of bladed pump.

Pomfrets are one of the most ample high priced fisheries of the Bay of Bengal, Bangladesh. The present study featuring the comparison of the life history parameters of three Pomfrets i.e. Silver (Pampus argenteus), Chinese (P. chinensis) and Black (Parastromateus niger) is based on the monthly length frequency data from the commercial landings from July 2015 through June 2016. The length (TL) of all three Pomfrets ranged from 8 to 55cm and weight (W) varied from 24 to 1302g. An allometric growth pattern was found in all cases when estimating LWR. The VBGF parameters for silver pomfret was L∞= 54.6cm, K= 0.39yr-1 while it was 54.6cm, 0.62yr-1, 57.75cm, and 0.94yr-1 for both Chinese and black pomfrets, respectively. Based on LCCC analysis the total mortality (Z), natural mortality (M) and fishing mortality (F) for silver and Chinese pomfrets were found to be the lowest compared with some previous studies related to the Indian Ocean, whereas black pomfret showed higher mortality rates to some extent. The exploitation ratio (E=F/Z) of silver and Chinese pomfrets were lower than the Gulland (1971) criterion of demarcation point of 0.5 and was higher for black pomfret which showed over-exploited stocks.  The YPR analysis also showed the heavily exploited state of black pomfret fishery, therefore, immediate management approach should be required to maintain sustainable stocks.

Eriocheir sinensis, which is an important aquaculture species, belongs to the class Crustacea. To discuss the temperature tolerance of E. sinensis, the survival rates of juvenile crabs of E. sinensis were determined in this paper using a series of temperature settings (normal temperature, 25°C, 30°C, 32°C, 34°C, 35°C, 36°C, 38°C, 40 °C). The results indicated that except the normal temperature level, mortality rate almost reached 100% at other temperatures. The time of death of all crabs at 30℃, 35℃, and 40℃ was different. All the crabs died in only 10 minutes at 40℃, while they died after 3 days and 7 days at 35 ℃ and 30℃, respectively. In addition to normal temperature conditions, minimum survival time of the juvenile crabs of E. sinensis at other temperature condition was no more than 24 h. Before the 8th day, the death rate at 30℃ and normal temperature was different, change of turning slope for concentration of NH3-N and TN was contrary. Under normal temperature, the behavior of abdomen extension was not observed in juvenile crabs but the percentage time of abdomen extension was relatively long at 25℃. This research studied the influence of temperature stress on the survival of juvenile crabs of E. sinensis to provide information reference for the production and transportation of juvenile crab of E. sinensis.