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• Fracture mechanism of graphite stationary ring in one type of mechanical seal is explained logically based on the results obtained via scanning electron microscopies. • A method considering the fluid, solid and thermal coupling effects is developed for calculation of loading conditions of graphite stationary ring. • The finite element analysis of the graphite ring, taking into account loading conditions, is carried out for the simulation of failure process. The loss of kinetic energy of moving parts due to viscous friction of lubricant causes the reduction of piston pump efficiency. The viscosity of lubricant film is mainly affected by the thermal effect. In order to improve energy efficiency of piston pump, this research presents a numerical method to analyze the lubricant film characteristics in axial piston pump considering the thermal effect by the coupled multi-disciplinary model, which include the fluid flow field expressed by Reynolds equation, temperature field expressed by energy equation and heat transfer equation, kinematics expressed by the motion equation. The velocity and temperature distributions of the gap flow of piston/cylinder interface in steady state are numerically computed firstly. Then the distributions are validated by the experiment. Finally, by changing the thermal boundary condition, the influence of thermal effect on the lubricant film, the eccentricity and the contact time between the piston and cylinder are analyzed. Results show that with the increase of temperature, the contact time increases in the form of a hyperbolic tangent function, which will reduce the efficiency of the axial piston pump. There is a critical temperature beyond which the contact time will increase rapidly, thus this temperature is the recommended as a design value. [ABSTRACT FROM AUTHOR]

• The interaction of the electron beam with the all-optical image sensor has been simulated based on the Monte Carlo computational method for the first time. • An InP-based all-optical image sensor was firstly applied in spatio-temporal characterization of pulse laser beams and paved the way for applications in electron and other particle beams. • Fringes in the recorded images have been effectively removed with a filter method based on Fourier transformation. • A differential method has been developed to increase the temporal resolution over the duration time of probe beams. A method for analyzing the spatio-temporal intensity distribution of pulse beams, such as photons, electrons and other particles, with an all-optical image sensor has been developed. The image sensor measures the photon or particle intensity by probing the induced refractive index change due to their excitation in the semiconductor. In order to prove this scheme, the interaction of the electron beam with the image sensor has been simulated, indicating that the transient phase grating can be created in the semiconductor. The transient phase grating can be probed with a laser to evaluate the spatio-temporal intensity distribution of the incident electrons. In addition, an InP-based image sensor has been established for analyzing pulse laser beams. A pump-probe technique has been utilized to record images with varying delays between the analyzed and probe lasers and a differential method has been developed to improve the temporal resolution to be less than the duration time of probe lasers. Sequential images, representing the spatio-temporal distribution of the analyzed laser beams with several hundreds of picoseconds temporal resolution, have been obtained, indicating the ability of this scheme for analyzing the spatio-temporal distribution of pulse laser beams and paving the way for promising applications in characterization of pulse particle beams. [ABSTRACT FROM AUTHOR]

Complete pump characteristics (CPCs) are the key for establishing pump boundary conditions and simulating hydraulic transients. However, they are not normally available from manufacturers, making pump station design difficult to carry out. To solve this issue, a novel method considering the inherent operating characteristics of the centrifugal pump is therefore proposed to predict the CPCs. First, depending on the Euler equations and the velocity triangles at the pump impeller, a mathematical model describing the complete characteristics of a centrifugal pump is deduced. Then, based on multiple measured CPCs, the nonlinear functional relationship between the characteristic parameters of the characteristic operating points (COPs) and the specific speed is established. Finally, by combining the mathematical model with the nonlinear relationship, the CPCs for a given specific speed are successfully predicted. A case study shows that the predicted CPCs are basically consistent with the measured data, showing a high prediction accuracy. For a pump-failure water hammer, the simulated results using the predicted CPCs are close to that using the measured data with a small deviation. This method is easy to program and the prediction accuracy meets the requirements for hydraulic transient simulations, providing important data support for engineering design. [ABSTRACT FROM AUTHOR]

Abstract: An underground power cavern situated in bedded sandstone rocks was evaluated using the finite element method. The rock formation had a set of joints vertically with an opening of less than 0.1mm. A “bedded model” was used to analyze the stability of the cavern excavation. The calculations were then checked by an “imitative model”. The results from these two models were consistent with each other. The results from the “bedded model” were similar to the displacements from the field measurements. The paper describes details of the numerical model, presents the results of the numerical calculations and discusses possible reasons for the similarities between the field measurements and results of the computations. [Copyright &y& Elsevier]

Surface properties of three cationic bolaamphiphile eicosanediyl 1,20-bis(pyridinium bromide) [Py+(CH2)20Py+]2Br−, phenyl 1,4-bis(oxyhexyl trimethyl ammonium bromide) (C6PhC6), phenyl 1,4-bis(oxydecyl trimethyl ammonium bromide) (C10PhC10), and their mixed systems with oppositely charged conventional surfactant sodium dodecyl sulfite (SDS) were studied. The results showed that bolaamphiphiles with rigid group also adopted reverse U-shape conformation at the air/water interface as those with flexible skeleton. Micellization in these bolaamphiphile systems is easier than those of the comparable conventional surfactants. Micellization thermodynamic parameters were calculated according to the phase separation model and entropy was found to be the main driving force in the process of micellization. Diagrams for the C6PhC6/SDS and C20Py2/SDS mixed systems were constructed based on the regular solution theory. It was found that the structural difference between the two bolaamphileles affects the interaction between the two components in each mixed systems greatly. [Copyright &y& Elsevier]

With the development of society and changes in the human living environment, people are increasingly attaching importance to their own health. Regarding medical imaging examinations of certain parts of the body, the process of medical image segmentation has become extremely important. This paper presents a novel hybrid algorithm: SAOBL-IA, a fusion of the Simulated Annealing(SA), Opposition-based Learning(OBL)and Island Algorithm(IA). The Island Algorithm itself suffers from slow convergence speed and the tendency to get stuck in local optimum. To address these limitations, we introduce opposition-based learning to enhance the search range and avoid local optimum. Furthermore, we leverage the simulated annealing approach to accelerate the convergence of SAOBL-IA. Comparing the experimental results, it can be seen that SAOBL-IA has better comprehensive performance. Subsequently, the SAOBL-IA algorithm is utilized in conjunction with an optimized two-dimensional OTSU fusion segmentation technique for the purpose of medical image processing. This study proposes an application of image segmentation based on the SAOBL-IA. The segmentation of pixels around the background and target regions using the two-dimensional OTSU method faces challenges in terms of accuracy. To address this issue, an adaptive thresholding technique known as Adaptive Forking is employed for optimization. By determining the slope of the fork based on the misclassified pixel ratio, enhanced segmentation accuracy can be achieved. This improved approach is then integrated with the SAOBL-IA algorithm and applied to the segmentation of lung medical images. The experimental findings show that the amalgamation of SAOBL-IA with the adaptive two-dimensional OTSU segmentation approach, as proposed in this study, manifests superior segmentation speed and enhanced precision in the context of medical image segmentation., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 JiMing et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Backgrounds: Distal pancreatectomy fistula risk score (D-FRS) and DISPAIR-FRS has not been widely validated for predicting postoperative pancreatic fistula (POPF) after distal pancreatectomy (DP)., Methods: We retrospectively analysed 104 patients undergoing DP. The predictive value of the D-FRS and DISPAIR-FRS were compared. Risk factors associated with POPF were investigated by multivariate analysis., Results: Of the 104 patients, 23 (22.1%) were categorized into the POPF group (all grade B). The areas under the ROC (AUCs) of the D-FRS (preoperative), D-FRS (intraoperative), and DISPAIR-FRS were 0.737, 0.809, and 0.688, respectively. Stratified by the D-FRS (preoperative), the POPF rates in low-risk, intermediate-risk, and high-risk groups were 5%, 22.6%, and 36.4%, respectively. By the D-FRS (intraoperative), the POPF rates in low-risk, intermediate-risk, and high-risk groups were 8.8%, 47.1%, and 47.4%, respectively. By the DISPAIR-FRS, the POPF rates in low-risk, intermediate-risk, and extreme-high-risk groups were 14.8%, 23.8% and 62.5%, respectively. Body mass index and main pancreatic duct diameter were independent risk factors of POPF both in preoperative (P = 0.014 and P = 0.033, respectively) and intraoperative (P = 0.015 and P = 0.039) multivariate analyses., Conclusion: Both the D-FRS (preoperative), D-FRS (intraoperative), and DISPAIR-FRS has good performance in POPF prediction after DP. The risk stratification was not satisfactory in current Asian cohort., (© 2023 Royal Australasian College of Surgeons.)

A single-shot imaging system with multiple frames has been developed, which can record sequential multiple frames by delaying multiple optical images with fiber bundles and then capturing the images with a single intensified camera. The observed optical object is imaged through four lenses onto the end faces of four sets of fiber bundles. These fiber bundles with different lengths can provide different delays for delivering optical images, which determine the inter-frame separation times. The optical images exported from the fiber bundles are captured with a single intensified CMOS camera simultaneously. This imaging system has been applied for investigating the dynamic x-ray spot of the rod-pinch diode via a combination of scintillators, which are used to convert x-ray images to optical images. Four sequential x-ray images in a single shot have been obtained, which show the dynamic development of the rod-pinch x-ray spot. The results experimentally reveal the dynamics of the electrons flow bombarding the rod, which roughly agrees with the theoretical modeling of the rod-pinch diode.

Scope: Choline is an essential nutrient and a primary dietary source of methyl groups that are vital for brain development. Low choline (LC) in the maternal diet during pregnancy alters neurogenesis in the fetal brain and leads to low cognitive performance. However, the key signaling pathways that are sensitive to maternal choline supply during neural progenitor cell (NPC) development and the epigenetic mechanisms by which choline availability regulates gene expression are unclear., Methods and Results: Timed-pregnant Nestin-CFPnuc transgenic mice are fed either a control diet or LC diet during E11-17. Gene expression changes in sorted E17 NPCs are identified by RNA sequencing. A maternal LC diet significantly increases Tlr4 transcription, causing premature neuronal differentiation and enhanced ethanol-induced NLRP3 inflammasome activation. No changes in DNA methylation at the Tlr4 gene promoter region are detected; however, a 70% decrease in H3K27me3 is observed in the LC-treated NPCs. Inhibition of EZH2 decreases H3K27me3 levels and increases Tlr4 expression. Conversely, the application of catalytically inactive Cas9 with EZH2 to increase H3K27me3 at the Tlr4 promoter causes reduced Tlr4 expression., Conclusion: These data reveal an epigenetic mechanism for the effect of maternal choline availability on brain development, suggesting a likely intervention for neurodevelopmental diseases., (© 2020 Wiley-VCH GmbH.)

An all-optical framing camera has been developed which measures the spatial profile of photons flux by utilizing a laser beam to probe the refractive index change in an indium phosphide semiconductor. This framing camera acquires two frames with the time resolution of about 1.5 ns and the inter frame separation time of about 13 ns by angularly multiplexing the probe beam on to the semiconductor. The spatial resolution of this camera has been estimated to be about 140 μm and the spectral response of this camera has also been theoretically investigated in 5 eV-100 KeV range. This camera has been applied in investigating the imploding dynamics of the molybdenum planar wire array Z-pinch on the 1-MA "QiangGuang-1" facility. This framing camera can provide an alternative scheme for high energy density physics experiments.

In order to eliminate the intrinsic noise due to special structure of the wrist, a new curve fitting algorithm based on singular value decomposition (SVD) was developed to increase the measurement accuracy. This algorithm could be subdivided into SVD and curve fitting algorithm (SCFA). SVD was used to extract the dominant component of oscillation waves at wrist. Then oscillation amplitudes of dominant component and cuff pressure were used to determine arterial blood pressure (ABP) with curve fitting algorithm. To test the performance of SCFA, 45 subjects underwent the ABP measurement with different methods. The correlation coefficient between the pooled blood pressure measured by the auscultation and those by SCFA was 0.96. Comparison the results of SCFA with those of traditional curve fitting algorithm (TCFA), we found that the proposed SCFA could be used to reduce the partial intrinsic interference and efficiently improve the accuracy of the ABP at wrist.

A facile, dextran-directed solution route for the morphology- and structure-controlled synthesis of PbWO(4) crystals, such as monoclinic raspite PbWO(4) nanobelts and tetragonal stolzite PbWO(4) crystals with penniform and wheat-ear-like morphologies, has been demonstrated. Three differently charged dextrans were employed for the PbWO(4) crystallization and they turned out to be very effective in the morphological and structural modulation of PbWO(4) crystals, as evidenced by the scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD) and Raman spectroscopy characterizations. In particular, novel monoclinic raspite PbWO(4) nanobelts were produced under the direction of anionic dextran with a suitable concentration, probably due to the specific interactions between SO(4)(2-) groups from anionic dextran molecules and Pb(2+) ions from PbWO(4) crystals. To the best of our knowledge, this is the first synthesis of monoclinic raspite PbWO(4) in the laboratory, which usually exists as a natural crystal. In addition, the photoluminescence properties of the obtained PbWO(4) crystals with different morphologies and crystal structures have been characterized and discussed, which provides useful information for the fundamental investigation and potential application of PbWO(4) crystals.

The formation of penniform BaWO4 nanostructures made of nanowires or nanobelts under the direction of a block copolymer in catanionic reverse micelles has been studied in detail. On the basis of the experimental results obtained from the BaWO4 crystallization in aqueous polymer solutions and careful transmission electron microscopy (TEM) observations of BaWO4 nanostructures formed in reverse micelles containing polymers, a detailed two-stage growth mechanism has been proposed for the formation of the penniform nanostructures in reverse micelles, which involves the polymer-controlled shaft formation (Stage 1) and the mixed surfactants-controlled barb growth (Stage 2). During Stage 1, poly(ethylene glycol)-block-poly(methacrylic acid) (PEG-b-PMAA) induced the formation of c-axis-oriented shuttle-like nanocrystals and the subsequent oriented attachment of these shuttle-like nanocrystals resulted in the formation of [100]-oriented shafts with many parallel [001]-oriented pricks. During Stage 2, [001]-oriented nanowires or nanobelts grew gradually from the pricks into barbs, leading to the formation of well-defined penniform BaWO4 nanostructures with the barb morphology essentially determined by the mixing ratio r of the anionic to cationic surfactants (i.e., nanowires were formed at r=1 while nanobelts were formed at r deviating from 1). The current understanding of the growth mechanism of penniform BaWO4 nanostructures in catanionic reverse micelles involving polymers may be potentially applied for designing a new synthesis system for the controlled synthesis of other hierarchical 1D nanostructures with desired architectures.