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A tooth root bending stress analysis method is proposed to study the tooth surface load distribution and tooth root bending stress during the meshing process of orthogonal face gear. Firstly, the tooth surface equation, transition surface equation and tooth width constraints are derived. Then, Through the tooth contact analysis (TCA), the contact path and spots of the face gear pair are obtained. What's more, the proposed method based on Load tooth contact analysis (LTCA) is utilized to calculate the tooth surface load distribution and root bending stress of the face gear along the mesh cycle and compared with the finite element method. Meanwhile, root bending stress tests were carried out to verify the proposed method. The comparisons indicate that the proposed method has higher computational efficiency compared with the finite element method (e.g. the finite element method takes about 5 h for a mesh cycle and the proposed method costs 40 s). The results show that the tooth surface load distribution and root bending stress of the proposed method are consistent with those obtained by the finite element method and gear root stress experiment. [ABSTRACT FROM AUTHOR]

Due to machining errors, location inaccuracies, human error, and various other factors, it is challenging to avoid assembly errors during the production of spiral bevel gears (SBGs). When SBG assembly errors occur, it can cause the appearance of edge contact and may even lead to severe tooth tip chipping. In this study, we propose an improved method based on loaded tooth contact analysis (LTCA) to examine mesh characteristics, including time-varying mesh stiffness (TVMS), unloaded transmission error, and contact stress. Furthermore, we explore the effects of assembly errors and tooth tip chipping. Moreover, it is observed that assembly errors can alter the contact area of SBGs and potentially reduce the peak-to-peak value of TVMS. Additionally, the occurrence of tooth tip chipping decreases TVMS within the chipping region, lowers transmission error, and increases maximum contact stress. Notably, when assembly errors are present, the reduction in TVMS due to tooth tip chipping exceeds that of a properly assembled SBG pair. [ABSTRACT FROM AUTHOR]

Simple Summary: The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) is an endangered freshwater whale unique to the Yangtze River in China. We compared and analyzed the gene expression of the Yangtze finless porpoise in semi-natural and controlled environments, based on blood transcriptomics methods. The results showed that the acoustic behavior and auditory-related genes of the Yangtze finless porpoise may show responsive changes and differential expression under different environment conditions, and thus the auditory sensitivity may also show corresponding adaptive characteristics. This study provides a new perspective for the further exploration of the responsive changes of the two populations to various environments and provides a theoretical reference for further improvements in conservation practices for the Yangtze finless porpoise. The Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis) living in different environments display significant differences in behavior and physiology. To compare and analyze gene expression differences between an ex situ population and a controlled environment population of the Yangtze finless porpoise, we sequenced the transcriptome of blood tissues living in a semi-natural reserve and an artificial facility, respectively. We identified 6860 differentially expressed genes (DEGs), of which 6603 were up-regulated and 257 were down-regulated in the controlled environment vs ex situ comparison. GO and KEGG enrichment analysis showed that the up-regulated genes in the controlled environment population were significantly associated with glucose metabolism, amino acid metabolism, and the nervous system, while those up-regulated in the ex situ population were significantly associated with energy supply and biosynthesis. Further analysis showed that metabolic and hearing-related genes were significantly affected by changes in the environment, and key metabolic genes such as HK, PFK, IDH, and GLS and key hearing-related genes such as OTOA, OTOF, SLC38A1, and GABBR2 were identified. These results suggest that the controlled environment population may have enhanced glucose metabolic ability via activation of glycolysis/gluconeogenesis, the TCA cycle, and inositol phosphate metabolism, while the ex situ population may meet higher energy requirements via enhancement of the amino acid metabolism of the liver and muscle and oxidative phosphorylation. Additionally, the acoustic behavior and auditory-related genes of Yangtze finless porpoise may show responsive changes and differential expression under different environment conditions, and thus the auditory sensitivity may also show corresponding adaptive characteristics. This study provides a new perspective for further exploration of the responsive changes of the two populations to various environments and provides a theoretical reference for further improvements in conservation practices for the Yangtze finless porpoise. [ABSTRACT FROM AUTHOR]

The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis, YFP) is an endangered species endemic to the Yangtze River in China, and it is the only freshwater whale in the genus Neophocaena. In terms of protection, three effective conservation strategies exist: in situ conservation, ex situ conservation, and artificial breeding, all of which have been implemented by the Chinese government. Of these, ex situ conservation involves the relocation of Yangtze finless porpoises to semi-natural waters with less human interference, and artificial breeding involves the relocation of Yangtze finless porpoises to a controlled environment that is more strictly managed. To compare and analyze the responsive changes in gene expression of the YFPs between the ex situ and controlled environments, we performed the RNA sequencing of blood tissues from these YFPs. A total of 1201 differentially expressed genes (DEGs) were identified, of which 423 were up-regulated in the ex situ population and 778 were up-regulated in the controlled-environment population. Gene enrichment analysis showed that 1201 DEGs between the ex situ and controlled-environment populations were generally enriched for vision-, digestion- and immune-system-related pathways. Further analysis revealed that several key immune system pathways, such as the chemokine signaling pathway and B cell receptor signal pathway, were activated in the ex situ population. In addition, the key pathways related to vision, including phototransduction and the inflammatory mediator regulation of TRP channels, as well as the pathways related to the digestive system, such as protein digestion and absorption and salivary secretion, were activated in the controlled-environment population. These results suggest that the ex situ populations may respond to complex environmental conditions in semi-natural waters by enhancing their immune function through the increased expression of immune-related genes and that the visual function and protein digestion of the YFPs were improved compared to those of the ex situ population based on the conditions of artificial feeding, such as the higher transparency of the water and regular feeding. This study provides clues for evaluating the adaptability of YFPs to different environments and is a useful reference for future ex situ conservation and artificial breeding. [ABSTRACT FROM AUTHOR]

The tooth root crack fault is a common fault type of the spiral bevel gear pair (SBGP). Affected by the strong bearing capacity, the early crack fault of the SBGP cannot be found in time. In this study, a finite element (FE) model of the SBGP is established and assembled through the tooth contact analysis. The maximum tooth root stress is analyzed considering the variation of assembly errors. Meanwhile, this study simulates the tooth root crack fault of the bevel pinion with different crack degrees. The initial position of the crack is located where the maximum tooth root stress appears. The time-varying mesh stiffness (TVMS) of the SBGP considering different degrees of the pinion tooth root crack fault is obtained. The TVMS and the non-load transmission error are brought into a hybrid FE dynamic model, and steady responses are solved. Based on this, the sensitivities of various statistical indicators for identifying the tooth root crack fault of SBGP under the influence of assembly errors are verified. This paper can provide the necessary theoretical basis for the analysis and diagnosis of tooth root crack faults in the SBGP transmission system. [ABSTRACT FROM AUTHOR]

Taking the effect of actual surface topography under elastohydrodynamic lubrication (EHL) conditions on the contact state of gear pairs into consideration, a combination model with the analytical sliced method and two-dimensional (2D) EHL model is proposed to characterize the three-dimensional (3D) meshing characteristics of spur gears. Firstly, the surface topology of gears is tested by a surface profiler, which reflects that the topography of tooth surface accords with fractal characteristics. Thus, by adopting the Weierstrass–Mandelbrot (W-M) fractal function, the gear surface is characterized. Secondly, the numerical 2D EHL model with fractal roughness is established, and distributions of oil film pressure (OFP) and oil film thickness (OFT) at different meshing positions are obtained. Finally, considering the different topography distributions in the direction of face width, time-varying mesh stiffness (TVMS) is calculated based on the analytical sliced method. Thus, the influence of 3D surface topography can be considered. The Hertz contact stiffness is substituted by the time-varying lubricating oil film stiffness (OFS). The influences of tooth surface topography and lubricant film characteristics on meshing characteristics are investigated. The results show that the 3D rough tooth surface may be well characterized by a fractal function with random phase. Moreover, there is a great difference in the distribution of OFP and OFT between rough and smooth surfaces, which certainly influences the gear meshing characteristics. [ABSTRACT FROM AUTHOR]

Extensive assessment about the efficiency and quality of the power production is important to the floating wind turbine (FWT) development. The power performance of a wind turbine depends on turbine dynamics, control strategy, and atmospheric conditions. As for FWTs, the additional floater oscillations should be particularly incorporated. In this paper, extensive simulations are conducted for a Spar‐type FWT using the FAST software. The relative wind velocity introduced by floater oscillations and the corresponding power capture mechanisms are analyzed in detail. A concept of equivalent turbulence intensity is proposed to generally describe the intensity of floater oscillation. It is observed to satisfyingly serve as an independent variable for FWT power production. The mapping relationship between the FWT power generation and the equivalent turbulence intensity is constructed. Results show that the FWT output power increases linearly with the equivalent turbulence intensity square in the below‐rated region, while it is well regulated around the rated power by the bladepitch controller in the above‐rated region. The normalized power fluctuation augments linearly with equivalent turbulence intensity over the whole operating wind speeds except the rated‐nearby region. The findings are potentially helpful for the power forecasting, controller development, economical evaluation, and wind farm optimizations. [ABSTRACT FROM AUTHOR]

In recent years, vision-based vibration measurement methods have been widely used in the field of mechanical engineering for structural health monitoring and fault diagnosis. However, these current methods mainly focus on monitoring the stationary vibrations of time-invariant systems or structures, which cannot deal with the time-varying conditions. In this paper, a video camera is used to monitor the non-stationary vibrations of a time-varying structure for an unexplored usage of moving mass detection. In the study, the laboratory time-varying structure is a clamped beam with one or more masses sliding on. The general parameterized time-frequency transform is first introduced to extract the time-dependent instantaneous frequencies (IFs) from the video motions. Then a parameterized mathematical model is proposed to estimate the weight of the moving mass based on the extracted IFs. By optimizing the parameters in this model, the moving mass can be estimated with high precision. Besides, multi-moving masses can be also detected for abnormal mass classification and identification. Both the finite element method (FEM) and experiments are performed to demonstrate the performance of the proposed vision-based moving mass detection (VMMD) technique. The VMMD technique has valuable potential for online detection, localization and classification of inferior products with abnormal mass in industrial automation. [ABSTRACT FROM AUTHOR]

A “slice method” is adopted to calculate the time-varying mesh stiffness (TVMS) of helical gear pairs, where the tooth is divided into many individual sliced spur gears along the tooth width, and the TVMS of helical gear pairs is obtained by accumulating the TVMS of the sliced spur gear pairs. Based on the slice method, an improved analytical method (IAM) is proposed to calculate TVMS of the helical gear pairs. The proposed method is also verified by comparing TVMS obtained from IAM with that obtained from references and the finite element method. Based on the proposed IAM, the effects of the helix angle, gear width, modification coefficient and friction coefficient on mesh characteristics are also discussed. The results show that the total contact ratio of helical gear changes under different helix angles and gear tooth widths, and the fluctuation of mesh stiffness will reduce when the overlap contact ratio approaches an integer. Meanwhile, addendum modifications can not only change the total contact ratio but also affect the mean mesh stiffness of gear pairs. Furthermore, not only will the friction coefficients affect the mean mesh stiffness, and it can lead to an abrupt change of TVMS in double-teeth engagement region. [ABSTRACT FROM AUTHOR]

Evodiamine-induced apoptosis has been shown to have anticancer activity by eradication of some carcinoma cell lines. This study was designed to evaluate the effects of evodiamine on the viability of human gastric cancer SGC-7901 cells and to define the cell death pathway. Flow cytometry detection showed that 1.5 μM evodiamine significantly induced SGC-7901 cell apoptosis in a time-dependent manner. This apoptosis was partially inhibited by the pancaspase inhibitor carbobenzoxy-valyl-alanyl-aspartyl-[ O-methyl]-fluoro-methylketone, which suggests that evodiamine-induced apoptosis in SGC-7901 cells is partially caspase independent. Further, the total content of sphingomyelin was decreased and expression of acid sphingomyelinase (aSMase) and neutral SMase genes in the SGC-7901cells was upregulated. Protein expression of aSMase, which was exposed to evodiamine, was shown to be increased by western blot analysis and could have been responsible for inducing caspase-independent apoptosis. Our results indicate that evodiamine stimulates upregulation of aSMase expression and hydrolysis of sphingomyelin into ceramide, which might be one of the mechanisms by which apoptosis occurs in SGC-7901 cells. [ABSTRACT FROM AUTHOR]

Using Neural Networks, this paper present a method of generating virtual images under virtual lighting conditions. The relationship between the lighting conditions and the color of image is non-linear, several neural networks technologies are introduced to make curve fitting. As a result, virtual images of same scene under different lighting conditions can be deduced from known real scene image, and the inherent relations of image color and outside lighting conditions are discovered. Combining techniques of IBMR or panoramic image, the model of scene is recovered. Further, combining the dynamic virtual images obtained by our method, time-sequence dynamic virtual scene can be reconstructed and revisited in virtual reality. [Copyright &y& Elsevier]

Background: Hepatic inflammation in patients with hepatocellular carcinoma (HCC) remains unclear. This study aimed to construct a clinically expedient predictive model to grade hepatic inflammation in HCC patients. Methods: This is a two-center retrospective cohort study of HCC patients comprising Derivation cohort and External Validation cohort of 1201 and 505 patients, respectively. Variables of liver inflammation identified through uni- and multi-variate logistic regression analyses were incorporated into predictive nomograms and applied to Derivation cohort, subject to internal and external validation. Results: Liver fibrosis severity score, portal hypertension severity, and model for end-stage liver disease-sodium independently predicted hepatic inflammation grade. Performance for distinguishing G1 and non-G1 (≥ G2) patients was good with C-index of 0.810 and 0.817 in Derivation and External Validation cohort, respectively. The nomogram performed poorly to predict grade G2, G3 and G2 + G3, but performed well to predict G4. Conclusions: Our nomogram exhibited good performance for scaling hepatic inflammation (G1 and G4) in HCC, and could be employed as adjunctive diagnostic tools to guide HCC management strategy. [ABSTRACT FROM AUTHOR]

To ensure the track of the deep buried hill horizontal wells can effectively enter the buried hill reservoir and drill in the favorable reservoirs as geologists desired, we have established a method for designing the hole deviation angle of horizontal well for detecting the surface of deep buried hills. Taking the designing of the well trajectories starting from the high position of the buried hill to the low position, where entering the buried hill reservoir is relatively dififcult and the favorable reservoirs tend to be drilled through as the research object, we have analyzed the relationship of the formation dip, reservoir thickness, tool angle building capability, and the designed inclination for detecting the surface of buried hills;considered the main inlfuence factors, such as the angle between forma-tion dip and designed azimuth, prediction error of the formation dip, the error of thickness prediction of the proiftable reservoirs, etc.;established the model for calculation of the hole inclination for detecting the buried hills and have applied it to the design of horizontal wells into buried hills in Jidong Oilifeld. The actual drilling shows that the design method has achieved the goal of effectively detecting the buried hill surface and drilling along the proiftable reservoirs as the geologists desired. [ABSTRACT FROM AUTHOR]

This manuscript describes the synthesis of green long afterglow nanophosphors SrAl2O4:Eu2+, Nd3+ using the combustion process. The study encompassed the photoluminescence behavior, elemental composition, chemical valence, morphology, and phase purity of SrAl2O4:Eu2+, Nd3+ nanoparticles. The results demonstrate that after introducing Eu2+ into the matrix lattice, it exhibits an emission band centered at 508 nm when excited by 365 nm ultraviolet light, which is induced by the 4f65d1→4f7 transition of Eu2+ ions. The optimal doping concentrations of Eu2+ and Nd3+ were determined to be 2% and 1%, respectively. Based on X-ray diffraction (XRD) analysis, we have found that the physical phase was not altered by the doping of Eu2+ and Nd3+. Then, we analyzed and compared the quantum yield, fluorescence lifetime, and afterglow decay time of the samples; the co-doped ion Nd3+ itself does not emit light, but it can serve as an electron trap center to collect a portion of the electrons produced by the excitation of Eu2+, which gradually returns to the ground state after the excitation stops, generating an afterglow luminescence of about 15 s. The quantum yields of SrAl2O4:Eu2+ and SrAl2O4:Eu2+, Nd3+ phosphors were 41.59% and 10.10% and the fluorescence lifetimes were 404 ns and 76 ns, respectively. In addition, the Eg value of 4.98 eV was determined based on the diffuse reflectance spectra of the material, which closely matches the calculated bandgap value of SrAl2O4. The material can be combined with polyacrylic acid to create optical anti-counterfeiting ink, and the butterfly and ladybug patterns were effectively printed through screen printing; this demonstrates the potential use of phosphor in the realm of anti-counterfeiting printing. [ABSTRACT FROM AUTHOR]