x. li

The deflagration of oil mist in closed chambers often causes severe ship fire accidents. Based on a self-built visual oil mist deflagration experiment platform, this research analyzed the effect of the spray time on the oil mist deflagration characteristics and focused on the flame propagation process, velocity, gas temperature, and overpressure in a closed chamber. The results show that with increasing spray time, the flame propagation velocity, gas temperature and deflagration overpressure increased. However, with the continuous increase in spray time, the deflagration characteristics of oil mist decreased. When the spray continued for 35 s, the peak overpressure was measured to be approximately 1.655 MPa. When the spray time extended to 95 s, the peak overpressure decreased by approximately 31.2% relative to the value at 35 s because the increase in spray time contributed to a more stable spray state and a larger diffusion range. Concurrently, the evaporation of liquid droplets increased of the kerosene vapor content. These factors contribute to a more intense oil mist deflagration. However, continuous increase in spray time results in an excessive accumulation of fuel, which makes an insufficient reaction and a significant reduction in deflagration characteristics. Oil mist deflagration process can be divided into four stages: deflagration, turbulent combustion, stretching and self-extinguishing. The high-temperature and high-pressure range of oil mist deflagration concentrate near the deflagration center, approximately 100 cm from left wall of the chamber.

Due to the installation space constraints in practical applications, centrifugal compressors often utilize bent intake pipes. Quantifying the correlation between the centrifugal compressor’s operating performance and the flow dynamics within curved inlet tubes is essential. In this research, the accuracy of the numerical methodology was validated using the experimental outcomes. Subsequently, the centrifugal compressor’s performance was simulated for two intake curved ducts, i.e., Pc with a coplanar central axis and Pnc with a non-coplanar central axis, followed by the analysis of the flow characteristics for each intake configuration. The results indicated that Pc produced a symmetrical swirling flow field at the outlet, which was characterized by a lower plane superimposed distortion intensity (PSDI), while Pnc generated an asymmetrical offset swirling flow field with a higher PSDI. The PSDI increased with the flow rate, reaching maximum values of 0.137 for Pc and 0.386 for Pnc. Compared to the inlet straight tube, the performances of the centrifugal compressor connected to Pc and Pnc both decreased, while Pnc exhibited a more significant performance deterioration degree. Under high-speed conditions, the maximum degradation degrees of pressure ratio for Pc and Pnc reached approximately 5.7% and 9.8%, respectively, while the efficiency reduction degree reached approximately 5.3% and 8.7%, respectively. The performance reduction degree for both bent pipes increased with the rising PSDI, exhibiting an exponential correlation. The flow characteristics of the intake pipelines affected the flow behavior within the impeller, with the flow field variation locations closely resembling the distorted regions of the bent pipes.

The purpose of this study is to evaluate the value of computed tomography (CT) / magnetic resonance imaging (MRI) fusion imaging technology in the diagnosis and staging of liver cancer.

Sixty patients with primary hepatocellular carcinoma diagnosed by histopathology and cytology who visited our hospital from April 2021 to May 2023 were selected. All patients underwent CT and MRI single mode scans, as well as CT/MRI fusion imaging scans. Based on the pathological diagnosis results, the consistency and accuracy of three imaging methods in evaluating the number, maximum diameter, and staging of liver cancer patients were compared.

CT/MRI fusion imaging can more accurately determine the number (F=8.62, P<0.001), maximum diameter (F=86.69, P<0.001), and pathological staging of liver cancer lesions compared to single CT or MRI. In terms of determining the number of tumors, CT/MRI fusion imaging is superior to CT (Kappa 0.695 vs 0.654) and MRI (Kappa 0.872 vs 0.695). In terms of evaluating the maximum pathway, CT/MRI fusion imaging has the highest consistency with MRI results (Kappa 0.931), which is significantly better than CT (Kappa=0.818). In staging judgment, CT/MRI fusion imaging improves the diagnostic accuracy of stages II and III tumors. 

The CT/MRI fusion imaging technology, which integrates the advantages of CT and MRI imaging examination modes, can improve the display rate, quantitative and staging evaluation accuracy of liver cancer lesions. And it is worthy of further promotion to improve the imaging fine diagnosis level of liver cancer.

The objective of this study was to examine the impact of synchronous low-dose splenic irradiation (LDSR) on immune function in patients with esophageal cancer undergoing radiotherapy.

Twenty-one patients who were diagnosed with esophageal cancer were randomly allocated to either the control or experimental groups. The control group received routine radiotherapy alone, whereas the experimental group underwent simultaneous LDSR during radiotherapy. Low dosage radiation refers to a beam with a low linear energy transfer (LET) that delivers a dose of 0.2 Gy or less, or a high LET beam that delivers a dose of 0.05 Gy or less, while maintaining an exposure dose rate of 0.005 cGy/min. The lymphocyte subsets in the two groups were analyzed using flow cytometry at various time points during and after treatment. Additionally, complications and their occurrence times were recorded simultaneously.

Gradual decreases were observed in CD16+CD56+, CD3+CD4+, and CD4+/CD8+ ratios following radiotherapy in the control group (p < 0.05). However, no considerable differences were observed between the experimental groups in these ratios (p > 0.05). LDSR was found to induce immunological enhancement and counteract immune suppression caused by radiotherapy. Furthermore, the experimental group experienced larger cumulative dosages that led to problems compared to the control group, with a delayed onset. Despite receiving a higher cumulative dose, the experimental group exhibited lower levels of myelosuppression and radiation esophagitis than the control group (p < 0.05). Overall, the results suggest that synchronous LDSR can enhance immune function during radiotherapy in patients with esophageal cancer and reduce the adverse effects associated with routine radiotherapy.

Synchronous LDSR may induce immunological enhancement during radiotherapy in patients with esophageal cancer, reduce adverse reactions to routine radiotherapy, and enhance tolerance.

We aimed to develop a mould for the over-flexion and over-extension positions to solve the technical problem of patients who find it difficult to form the over-flexion and over-extension positions of the cervical spine by lowering their heads forwards and raising their heads backwards.

We calculated the average physiological bending radian of normal people and measured the depth of the cervical physiological curve using Borden's method. Finally, we designed a mould that conformed to the characteristics of the human cervical spine to conduct nasal bone examinations in the over-flexion and over-extension positions in combination with the patient's examination position.

When the neck is equipped with an over-flexion and over-extension mould when performing coronal nasal bone examinations, the nasal bone structure is more fully displayed than in routine examinations; furthermore, the clinical diagnosis efficiency greatly improves, and the rate of misdiagnosis significantly reduces.

This model increases the comfort of patients and solves the technical problem of patients who cannot maintain the over-flexion and over-extension positions for an extended period.

With the increasing complexity of the industrial production process, the transmission medium of the hydraulic turbine is no longer satisfied, and the gas-liquid two-phase mixed medium has to be considered. The presence of gas in the transmission medium will alters the internal flow structure of the hydraulic turbine and affect its operational stability. Therefore, for the purpose of clarifying the influence of inlet gas content on the internal flow of PAT, the unsteady flow of the PAT is simulated in this paper using numerical simulation. Based on the numerical simulation results, the influence of inlet gas content on the internal flow characteristics, characteristics of pressure fluctuation in impeller and volute, and vortex evolution of flow field are analyzed. The accumulation of gas phase leads to the emergence of vortices, and regions with low pressure values appear at the vortex generation. The major factor of the periodic variation of pressure fluctuation between volute and cut-water is the dynamic and static interference of impeller. The increase of gas content causes more flow disorder in the cut-water region and the volute contraction section. Since the gas in the flow channel is predominantly on the suction side of blades, the flow field on the suction side is more complex than that on the pressure side, and the amplitude of pressure fluctuation increases appropriately. The vortex structure is mainly distributed on balance hole, inlet area of impeller and suction side of blade. As the blade rotates, there are new shedding and growth of vortices, and finally attached to the volute wall. Increasing gas content enhances the influence of blade rotation on the vortex evolution characteristics in the volute and impeller.

Water lubricated bearings can be used to reduce contamination due to lubricant leakage in heavy machinery such as power positioning systems of offshore platforms and ship propulsion systems. The lubrication model of a textured two-dimensional parallel friction pair and a textured water-lubricated journal bearing are developed to investigate the lubrication performance. The governing equation is solved, and the fluid cavitation is analyzed using the Zwart-Gerber-Belamri (ZGB) model. A multi-objective optimization method combining the response surface and Non-dominated Sorting Genetic Algorithm-II (NSGA-II) is used to optimize the textured journal bearings. The results indicate that a small texture width will inhibit the occurrence of liquid film cavitation. With the rise in the texture width, the cavitation effect gradually rises and stabilizes. As the texture depth deepens, the micro dynamic pressure effect is enhanced and liquid film pressure rises. Through the tests, it is found that the optimized texture parameters can be implemented to effectively diminish the friction and wear volume, also the optimized textured bearing hydrodynamic pressure effect is enhanced at the same speed.

The boundary layer's separation loss in compressor cascades constitutes a significant portion of profile loss, critically influencing aerodynamic performance optimization and control. This study employs Large Eddy Simulation (LES) to examine separation losses at varying attack angles, focusing on a rectangular compressor cascade. Specifically, it explores the long separation bubble at a 45% blade height cross-section under designed incidence. Analysis of the separation bubble's transition process revealed a notable surge in total pressure loss rate prior to transition, which stabilized following reattachment. The study thoroughly investigates the evolution of long bubbles, employing quadrant analysis of Reynolds stress, critical point theory, and an in-depth examination of individual vortex dynamics. The findings indicate that the peak of cross-flow within the separation bubble acts as the primary mechanism initiating the transition. This insight is corroborated by DNS calculations of natural transitions on flat plates. Building upon these findings, the study discusses the effects of varying attack angles on transition processes. Notably, increased incidence prompted the upstream migration of the long separation bubble, transforming it into a short bubble at the leading edge. This shift led to a fivefold increase in separation loss and doubled the frequency of transverse flow fluctuations.

The study aimed to elucidate the clinical application significance of prospective ECG-gated dual-source CT in central venous (CV) imaging.

Eighty patients who took CT imaging of CV (CTV) check using dual-source Force CT were enrolled. The control group (helical pitch, 0.8; rotation speed, 0.5 s) and the experimental group (rotation speed, 0.25 s). For both groups, image quality and radiation dose were computed.

Cases in the experimental group required longer scanning durations than those in the contro lgroup. In respect to the experimental group, the image quality scores of the superior vena cava and left and right brachiocephalic veins of the patients sharply increased relative to those in the control group. Individuals in the experimental group also presented better image quality scores in left and right subclavian veins, left and right jugular veins, however, this difference was not statistically significant. Lastly, no increase in the radiation dose was bited with the application of prospective ECG gating.

The clinical use of prospective ECG-gated technology significantly reduced cardiovascular pulsing artifact interference on the central vein, especially the superior vena cava segment, and remarkably improved the image quality without increasing the radiation dose to patients.

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.

Atanassov's intuitionistic fuzzy sets have succussed in the application of decision making, data mining, artificial intelligence, image processing, and so on. In these applications, intuitionistic fuzzy reasoning plays a crucial role. To improve the quality of intuitionistic fuzzy reasoning, this paper presents a quintuple intuitionistic fuzzy implication principle (QIIP) to resolve intuitionistic fuzzymodus ponens (IFMP) and intuitionistic fuzzy modus tollens (IFMT) problems. The QIIP algorithms of IFMP and IFMT problems for intuitionistic R-implication, S-implication, and several fuzzy implications are represented. Moreover, we investigate the recovery property and continuity of QIIP algorithms for IFMP and IFMT.Finally, an application example for medical diagnosis is implemented to illustrate our proposed approaches.

NatuAt present, radioactive seed implantation is a common treatment for prostate cancer, the TPS (treatment planning system) calculates the dose by adding the dose attributed to each source. However, the interseed attenuation effect would result in a difference between the actual dose and the calculated dose. The aim of this study was to identify the factors influencing the interseed attenuation effect.

I-125 seed sources were selected, and MC (Monte Carlo) method was used to simulate the dose distribution around seed sources. The results obtained from the linear addition of a single-source dose were compared with those obtained considering the interseed attenuation effect. The effects of the medium, source arrangement and source number on the dose were evaluated.

The MC simulation results for multiple seed sources are lower than those for linear additive doses in most areas. In different medium, the mean error caused by interseed attenuation effect is the smallest in adipose tissue (0.52%) and the largest in bone (1.41%). Taking four sources as examples, the maximum error is 9.34%, appearing in the plane where the source is located. The error decreases to 1.3% when the source is located 2 mm away from the source plane. The more scattered the sources are in space, the smaller the error will be.

A high atomic number and high-density medium will cause a high error. The area with a high error is mainly observed in the plane where the sources are located, the edge error of the source distribution area is larger.

The improved delayed detached eddy simulation (IDDES) method was employed based on the shear–stress transport (SST) k-w two-equation turbulence model to simulate the slipstream distribution characteristics of a high-speed train traversing a tunnel. The accuracy of the numerical simulation method was verified through a full-scale test. First, the wake vortex structure and the distribution of slipstreams of the train with a streamlined nose length of 7 m running in a tunnel were analyzed. Then, the influence of the streamlined nose length on the wake dynamics and slipstream was compared and analyzed. The slipstream positive peak decreased with increasing distance from the top of the rail and center of the track. As the streamlined nose length increases, the vortex intensity in the wake area weakens; moreover, the influence ranges of the wake vortex and the slipstream positive peak value become smaller. Compared with the results of a train having a streamlined nose length of 5 m, the slipstream positive peak value at 1.4 m from the top of the rail and 100 m from the tunnel entrance decreased by 46.6% from that of a train with a streamlined nose length of 9 m.

This study aims to investigate voxel-level dose calculation methods and improve its calculation efficiency in nuclear medicine that can consider animal-specific heterogeneous tissue compositions and radiopharmaceutical biodistributions simultaneously.

The voxelized mouse phantom was constructed from real mouse CT images and simulated using the Monte Carlo GEANT4 code. According to the dynamic PET images of real mouse, the real distribution of radiopharmaceutical activity was set in the Monte Carlo simulation. The sampling method to improve the calculation efficiency was proposed. Two voxel-level dose calculation methods were implemented in this study. The average absorbed dose in vital target organs and the tumor was calculated by the proposed voxel-level dose calculation methods and the traditional MIRD method respectively. The results of the average absorbed dose calculated by the two methods were compared. Based on the voxel-level dose calculation method, the three-dimensional dose distribution in organs and the tumor was obtained and evaluated.

The relative difference of average absorbed dose between the two voxel-level dose calculation methods was mostly less than 10%. The sampling method proposed to improve calculation efficiency for the voxel-level dose calculation can decrease the calculation time by ~34% with less deviation.

The results confirmed that the voxel-level dose calculation methods proposed in this study allow for more accurate and efficient assessment of the internal radiation dose.

Heilongjiang province is the main cattle-producing area in China, and molecular epidemiological studies of bovine viral diarrhea viruses (BVDV) in cattle have not been performed in the province.

The objective of this research was to determine the genetic and clinical characteristics of BVDV in cattle.

Fifty-three BVDV-positive clinical samples were collected from 22 cattle farms in Heilongjiang, and the 5´-untranslated region (5´-UTR) was used to carry out a phylogenetic analysis of the viruses.

The similarity of the 5´-UTR sequences among these BVDVs was 84.2%-100%, and the phylogenetic analysis showed that all viruses belong to the BVDV-1 species, which is classified into five subtypes: BVDV-1b (47.17%, n=25), 1c (15.09%, n=8), 1d (16.98%, n=9), 1 m (3.77%, n=2), and 1o (16.98%, n=9). The statistical results showed that the BVDV-1b subtype had a positive correlation with gastrointestinal disease (P<0.05; 95% CI: 1.19 to 3.34). There were up to three or four BVDV-1 subtypes in some dairy cattle farms, but farms with a single subtype were prevalent (5/10).

BVDV-1b is predominant in cattle herds of Heilongjiang province, China, and shows a positive correlation with gastrointestinal disease. BVDV-1o was found for the first time in Chinese cattle, which increased the complex distribution of BVDV-1 subtypes in cattle herds of China.

The gas-liquid two-phase flow with interfacial behaviors and bubble-liquid interactions is widely encountered in industrial processes such as that in gas-liquid reactors. The complicated phase structure makes it difficult to be modeled. The present work proposes a multi-scale mathematical model to simulate the bubbly flow in a square column. The volume of fluid (VOF) method is applied to treat the separated interface, and the discrete bubble model (DBM) is incorporated to handle the dynamics of dispersed bubbles. The hybrid model is validated against the benchmark experimental data to study the accuracy and suitability of the modeling framework for bubbly flows. And the influence of interphase forces on bubbly flow patterns and velocity profiles is investigated. It is found that the employment of both pressure gradient force and Ishii-Zuber drag model provides fairly good agreements with experimental data for velocity profiles.

Deoxyuracil triphosphate nucleotide (dUTP) pyrophosphatase (dUTPase, DU) is an enzyme of caprine arthritis-encephalitis virus (CAEV) that minimizes incorporation of dUTP into the DNA. Caprine arthritis-encephalitis virus relies partly on its ability to escape from innate immunity to cause persistent infections. Interferon β (IFN-β) is an important marker for evaluating the innate immune system, and it has a broad spectrum of antiviral activity. This study was conducted to investigate the details of the IFN-β response to CAEV infection. The expression of IFN-β and the proliferation of Sendai virus (SeV) and vesicular stomatitis virus (VSV) were determined by real-time quantitative polymerase chain reaction (qPCR). The effect of DU on the IFN signaling pathway was evaluated using luciferase reporter assays. In our study, the expression of IFN-β was significantly inhibited and the proliferation of SeV and VSV was promoted in cells overexpressing CAEV-DU. DU affected interferon stimulated response element (ISRE) and IFN-β promoter activities induced by RIG-I/MDA5/MAVS/TBK1 pathway, while did not affect them induced by interferon regulatory factor 3 (IRF3-5D). DU protein downregulated the production of IFN-β by inhibiting the activity of the signal transduction molecules upstream of IRF3, thereby, helping CAEV escape innate immunity. Findings of this work provide an evidence to understand the persistent infection and multiple system inflammation of CAEV.

This paper studies the mechanical behavior of two types of KLP sleeper, namely low-density polyethylene sleeper (LDPE-16) and high-density polyethylene sleeper (HDPE-25) with 16 mm and 25 mm steel bars diameter, respectively, in static, dynamic and longtime static three points bending moment tests. Therefore, HDPE-25 and LDPE-16 with six strain gauges mounted on their steel bars, were manufactured to assess their mechanical responses. Moreover, a finite element method (FEM) model is developed to perform a sensitivity analysis based on different diameters of steel bars for HDPE with 16 mm (HDPE-16) and LDPE with 25 mm (LDPE-25). The results show that steel bars of LDPE-16 yielded under 4 hours of 30 kN load, while, HDPE-25 shows significant resistance. Numerical results show that HDPE-25 is overdesigned and can be replaced by LDPE-25 which has lower weight and price. The natural frequencies of HDPE-25 are almost 16%, 19%, 16% and 33% higher than the three first bending frequencies and first torsion frequency of LDPE-25, respectively, that proves the better performance of LDPE-25 in case of preventing resonance. Moreover, the bending modulus HDPE-25 is almost 42%, 45% and 65% is higher than HDPE-16, LDPE-25 and LDPE-16, respectively.

Variation in flow direction requires extensive consideration in the practical application of riblet surfaces. However, studies scarcely examine the impact of flow angle α for riblet, which is usually adopted to reduce flow drag. Accordingly, this research conducted large eddy simulation for a wide range of flow angles. We explored the effect of 0° to 90° flow angle on the surface drag change of triangular riblet. The time-averaged statistical data and instantaneous flow details indicated that skin friction is decreased with the increase in α. However, pressure drag increased much faster than the friction decrease. Result revealed that skin friction reduction by 4.537% is obtained when α=0°, and it inhibits turbulence in the spanwise direction. When α≈20°, the total drag reduction disappeared. Within this range, the deviation angle showed little influence on the total drag reduction. When α=90°, skin friction is reduced by 73.3%; however the pressure drag and total drag increased, accompanied by an increased turbulence. The flow must be nearly parallel to the riblet to achieve drag reduction. Otherwise, the transverse riblet is an effective method to increase the drag.

A systematic way is presented for the construction of multi-step iterative method with frozen Jacobian. The inclusion of an auxiliary function is discussed. The presented analysis shows that how to incorporate auxiliary function in a way that we can keep the order of convergence and computational cost of Newton multi-step method. The auxiliary function provides us the way to overcome the singularity and ill-conditioning of the Jacobian. The order of convergence of proposed p-step iterative method is p + 1. Only one Jacobian inversion in the form of LU-factorization is required for a single iteration of the iterative method and in this way, it offers an efficient scheme. For the construction of our proposed iterative method, we used a decomposition technique that naturally provides different iterative schemes. We also computed the computational convergence order that confirms the claimed theoretical order of convergence. The developed iterative scheme is applied to large scale problems, and numerical results show that our iterative scheme is promising.