The machining accuracy of a copper electrode gear (CEG), especially the pitch deviation of CEG, is affected by the wear of the ball end mill (BEM) with the increase of the length of milling path. ...Based on the error mapping principle, this work focuses on the influence of BEM wear on pitch deviation. In order to dynamically compensate the influence of the BEM wear on pitch deviation, a novel milling pitch deviation compensation model was proposed based on the formation mechanism and measurement principle of pitch deviation. To ensure the uniform wear at the milling edge of the BEM during the milling process, BEM wear was firstly copied to the pitch deviation according to the tooth-by-tooth milling strategy. Then, the BEM wear curve was fitted based on orthogonal experiments and multiple linear regression. According to the wear curve, an offline compensation method was adopted to compensate for the pitch deviation caused by BEM wear. In addition, the reverse compensation principle was used to compensate for the normal deviation of BEM milling path. Finally, the compensation model was verified by milling experiments. Pitch deviation met the requirements of Levels 4
∼
5 in GB/T 38192-2019. The model can be used to guide the milling process of CEG.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Resolving the detailed structures of metal organic frameworks is of great significance for understanding their structure-property relation. Real-space imaging methods could exhibit superiority in ...revealing not only the local structure but also the bulk symmetry of these complex porous materials, compared to reciprocal-space diffraction methods, despite the technical challenges. Here we apply a low-dose imaging technique to clearly resolve the atomic structures of building units in a metal-organic framework, MIL-125. An unexpected node structure is discovered by directly imaging the rotation of Ti-O nodes, different from the unrotated structure predicted by previous X-ray diffraction. The imaged structure and symmetry can be confirmed by the structural simulations and energy calculations. Then, the distribution of node rotation from the edge to the center of a MIL-125 particle is revealed by the image analysis of Ti-O rotation. The related defects and surface terminations in MIL-125 are also investigated in the real-space images. These results not only unraveled the node symmetry in MIL-125 with atomic resolution but also inspired further studies on discovering more unpredicted structural changes in other porous materials by real-space imaging methods.Resolving the structures of MOFs is significant for understanding their structure-property relation. Here, authors apply a low-dose imaging technique to resolve the atomic structures of building units in MOF MIL-125. A low-symmetry structure of MIL-125 is discovered by directly imaging the rotated Ti-O nodes, different from the unrotated one predicted in previous works.
Through digitization, maintaining and promoting cultural heritage is being strengthened. Concerning this background, this study presents a new Indonesia cultural events dataset and automatic image ...classification for cultural events. The dataset was developed using the Flickr image platform, and the five cultural events image was collected including the Baliem Festival, Jember Fashion Festival, Nyepi Festival, Pacu Jawi, and Pasola Festival. Further, Convolutional Neural Networks (CNN) was developed for the classification method. A comparison of CNN models (VGG16 and VGG19) using several optimization configurations was performed to get the best model. The results showed that the VGG16 with image augmentation and dropout regularization technique performed best with 94.66% accuracy. This study hoped to support the heritage's digital documentation process and preserve Indonesia's cultural heritage.
When a milling tool is used to mill small modulus copper electrode gears (SMCEG), the deformation is inevitable, thus leading to the helix slope deviation (HSD) of copper electrode gears (CEG). To ...compensate the influence of milling tool deflection (MTD) on the HSD, a universal HSD compensation model was established for different sizes of milling tools. First, using the principle of orthogonal experiment, a linear regression model of milling parameters and milling tool radius is established. Secondly, the average value of the HSD obtained by the gear measuring instrument is converted into the maximum of MTD according to the principle of helix line formation. The maximum deflections of the milling tools are used as the response value of the regression analysis to fit the maximum deflection curve of the milling tool. Through the reverse adjustment of the rotation angle of the rotating motor, the HSD compensation is realized. Finally, the model was verified by the milling tests. The results showed that the helix deviation reached the requirements of level 4 to 5 in GB/T 38192-2019, and proved the correctness of the established MTD model. The model is significant for milling SMCEG.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Early fault warning for large-scale high-speed rotating machinery can effectively reduce unplanned downtime and avoid major safety accidents. Aiming at the problems of difficult screening of ...multi-source common sensitive features, the challenging training of neural networks with a small number of sensitive features, and the difficulty of directly using generative adversarial networks for early fault warning, this paper constructs an early fault warning model based on multi-source common sensitive features and an improved Wasserstein generative adversarial network, proposing an early fault warning method for rotating machinery. The model was verified by using the open XJTU-SY bearing laboratory data, the P3409A centrifugal pump bearing fault engineering case data of a petrochemical company and the rotor system engineering case data of a circulating hydrogen centrifugal compressor of a petrochemical company. The early fault warning method of rotating machinery proposed in this paper warns the bearing fault of centrifugal pump 160 hours in advance and the rotor system fault of centrifugal compressor 1330 minutes in advance. Compared with the two published methods, the proposed method has better early fault warning effect, better normal and abnormal health index discrimination and less false warning.
This study presents a genetic algorithm integrated with dynamic programming to address the challenges of the hydropower unit commitment problem, which is a nonlinear, nonconvex, and discrete ...optimization, involving the hourly scheduling of generators in a hydropower system to maximize benefits and meet various constraints. The introduction of a progressive generating discharge allocation enhances the performance of dynamic programming in fitness evaluations, allowing for the fulfillment of various constraints, such as unit start-up times, shutdown/operating durations, and output ranges, thereby reducing complexity and improving the efficiency of the genetic algorithm. The application of the genetic algorithm with dynamic programming and progressive generating discharge allocation at the Manwan Hydropower Plant in Yunnan Province, China, showcases increased flexibility in outflow allocation, reducing spillages by 79%, and expanding high-efficiency zones by 43%.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Cancer cells adapt to nutrient-deprived tumor microenvironment during progression via regulating the level and function of metabolic enzymes. Acetyl-coenzyme A (AcCoA) is a key metabolic intermediate ...that is crucial for cancer cell metabolism, especially under metabolic stress. It is of special significance to decipher the role acetyl-CoA synthetase short chain family (ACSS) in cancer cells confronting metabolic stress. Here we analyzed the generation of lipogenic AcCoA in bladder cancer cells under metabolic stress and found that in bladder urothelial carcinoma (BLCA) cells, the proportion of lipogenic AcCoA generated from glucose were largely reduced under metabolic stress. Our results revealed that ACSS3 was responsible for lipogenic AcCoA synthesis in BLCA cells under metabolic stress. Interestingly, we found that ACSS3 was required for acetate utilization and histone acetylation. Moreover, our data illustrated that ACSS3 promoted BLCA cell growth. In addition, through analyzing clinical samples, we found that both mRNA and protein levels of ACSS3 were dramatically upregulated in BLCA samples in comparison with adjacent controls and BLCA patients with lower ACSS3 expression were entitled with longer overall survival. Our data revealed an oncogenic role of ACSS3 via regulating AcCoA generation in BLCA and provided a promising target in metabolic pathway for BLCA treatment.
Background Dental follicle stem cells (DFSCs) show mesenchymal stem cell properties with the potential for alveolar bone regeneration. Stem cell properties can be impaired by reactive oxygen species ...(ROS), prompting us to examine the importance of scavenging ROS for stem cell-based tissue regeneration. This study aimed to investigate the effect and mechanism of N-acetylcysteine (NAC), a promising antioxidant, on the properties of DFSCs and DFSC-based alveolar bone regeneration. Methods DFSCs were cultured in media supplemented with different concentrations of NAC (0-10 mM). Cytologic experiments, RNA-sequencing and antioxidant assays were performed in vitro in human DFSCs (hDFSCs). Rat maxillary first molar extraction models were constructed, histological and radiological examinations were performed at day 7 post-surgery to investigate alveolar bone regeneration in tooth extraction sockets after local transplantation of NAC, rat DFSCs (rDFSCs) or NAC-treated rDFSCs. Results 5 mM NAC-treated hDFSCs exhibited better proliferation, less senescent rate, higher stem cell-specific marker and immune-related factor expression with the strongest osteogenic differentiation; other concentrations were also beneficial for maintaining stem cell properties. RNA-sequencing identified 803 differentially expressed genes between hDFSCs with and without 5 mM NAC. "Developmental process (GO:0032502)" was prominent, bioinformatic analysis of 394 involved genes revealed functional and pathway enrichment of ossification and PI3K/AKT pathway, respectively. Furthermore, after NAC treatment, the reduction of ROS levels (ROS, superoxide, hydrogen peroxide), the induction of antioxidant levels (glutathione, catalase, superoxide dismutase), the upregulation of PI3K/AKT signaling (PI3K-p110, PI3K-p85, AKT, phosphorylated-PI3K-p85, phosphorylated-AKT) and the rebound of ROS level upon PI3K/AKT inhibition were showed. Local transplantation of NAC, rDFSCs or NAC-treated rDFSCs was safe and promoted oral socket bone formation after tooth extraction, with application of NAC-treated rDFSCs possessing the best effect. Conclusions The proper concentration of NAC enhances DFSC properties, especially osteogenesis, via PI3K/AKT/ROS signaling, and offers clinical potential for stem cell-based alveolar bone regeneration. Keywords: N-acetylcysteine, Dental follicle stem cells, Cell differentiation, Bone development, Reactive oxygen species, Signal transduction
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Signal time-frequency analysis is widely used in industrial fields, for example, machinery fault diagnosis. Current methods cannot well address the multicomponents' signals with crossing frequency ...trajectories. For example, the adaptive decomposition methods have a mode-mixing problem. The linear transforms have smear problems due to the mutual interference caused by crossing frequencies. To address these issues, in this article, we propose an iterative approach named adaptive linear chirplet transform (ALCT). It works by calculating the signal linear chirplet transform (LCT) with a series of chirp rates as parameters, iteratively estimating the characteristics of the signal mode with the highest amplitude in the residual LCT and updating the residual LCT by removing the LCT of the detected mode, and constructing the signal time-frequency representation (TFR) based on the estimated characteristics of the detected modes. The ALCT can clearly reveal the TFRs of signals with crossing frequency trajectories. It does not have the frequency estimation errors caused by mode mixing and avoids the mutual interference of the crossing frequencies. It is efficient, as it can obtain the LCT of the detected mode by directly weighting and shifting the LCT reference. The effectiveness of the ALCT is validated using simulations and real-world signals.
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