bluuebunny/crossref_metadata_2025_split huggingface dataset:
A reliability evaluation method for RV reducer by combining multi-fidelity model and Bayesian updating technology
Authors: Jiang Z H , Zhang X L , Liu J Q 
Published: February 2021

Abstract
RV (rotating vector) reducer is a two-stage transmission mechanism composed of involute planetary gear transmission and cycloid gear transmission with small tooth difference. It is widely used in the transmission mechanism of industrial robots and CNC machine tools. Nonlinear dynamics of gear system is always an important and difficult problem, the randomness of manufacturing and assembly makes the dynamic response become more complex. In this paper, the stochastic dynamic response analysis and dynamic reliability estimation method is proposed for RV reducer. In this method, firstly, considering the uncertainties of manufacturing error and assembly error, the dynamic transmission performance is analyzed respectively using physical prototype test, virtual prototype simulation and theoretical model. Secondly, multifidly model and Bayesian theory are combined to estimate the statistical distribution and distribution parameters of the dynamic transmission error. Finally, the reliability of RV reducer is estimated, and the effects of uncertainties from manufacturing error and assembly error on the transmission accuracy are discussed.
GEOMETRIC UNCERTAINTY ANALYSIS OF A CENTRIFUGAL COMPRESSOR USING KRIGING MODEL
Authors: Li Shujiang , Huang Min , Liu Xuejun 
Published: February 2021

AbstractCentrifugal compressor, which is an important turbomachinery, plays a significant role in the gas turbine engine. Various uncertain factors in the manufacturing process can lead to the geometric variations, which often cause noticeable variations in compressor performance. In this paper, a surrogate-based uncertainty analysis method is used to investigate the effect of geometric uncertainty on the aerodynamic performance of a centrifugal compressor. Firstly, a scaled-up version of NASA DDA’s 404-III centrifugal compressor is chosen as the research object. Considering the structural features of the compressor, a parameterized model with 38 independent control parameters is established to define the geometry of the compressor, enabling rapid modification of the geometry. Then, a widely-used simulation method based on computational fluid dynamics is employed to predict the aerodynamic performance at a series of specified geometries generated using Latin Hypercube Design. Next, based on the sample data, two Kriging models are built to emulating the complex functional relationship between the control parameters and the performance of compressor. Finally, a Kriging model-based Monte Carlo simulation method is used to perform the geometric uncertainty analysis. After specifying a reasonable probability distribution for each control parameter, the statistical distributions of the compressor performance are obtained and analyzed. The analysis results yield new insights for compressor designers.
Predicting workers’ unsafe workspace with fuzzy logic-based procedures; exploiting injury count in work hours
Authors: Adeyemi H O 
Published: February 2021

Abstract
Loss due to accident in any workspace is either material or personal and its associated with costs of damages to machines and also injuries, disabilities and death to workers. In this study, a fuzzy logic based expert system called Workspace Injury Sensitive Expert System (WISES) was developed to predict the unsafe level of any workspace. Two input variables, hours-worked” and “Injury-Rate were fired into the system’s Mamdani inference engine to generate the output as “Workspace-unsafe-ratings”. Data were collected from 20 workers in 20 workspaces and were run with WISES. The outcomes were compared with values obtainable using the existing Workplace Hazards Rating Mathematical Expression (WHRME). There existed a strong relationship (correlation coefficient of 0.710) between WISES and WHRME. The WISES had a statistically significantly lower level of rating (0.50 ± 0.02, SEM= 0.007), t(38) = 1.613, p = 0.115 compared to WHRME (0.60 ± 0.30, SEM=0.004) and the prediction capacity of both the systems were not significantly different. The developed expert system can find applications in any work environment that is prone to accident. It can also enhance the planning ability of managers and decision makers in industries when assessing workplaces and/or work methods disposed to accidents.
The ensemble of surrogate model based on local and global errors
Authors: Zhang X , Li H , Xiang G , Xu H W 
Published: February 2021

Abstract
The weight coefficient is the key factor for the success of the ensemble of surrogate model construction. In this paper, a method for constructing ensemble of surrogate model by combining local and global errors to calculate weight coefficient has been put forward. Radial basis function (RBF) and the Kriging model are built as the meta models, and the cross validation strategy is applied to calculate the global errors and the local errors of samples. The inverse proportion average method is used to calculate the weight coefficient by combining the local errors and global errors. In order to verify the effectiveness of the proposed method, two meta models and three methods to construct the ensemble of surrogate models are tested with six benchmark functions. The results show that the proposed method can improve the accuracy, robustness and universality of the surrogate model.
An Advanced Method of Collision Risk Assessment in terms of Encountering Ships
Authors: Deng Yuting , Zhang Weibin , Feng Xinyu 
Published: February 2021

Abstract
In the risk management of maritime transportation, near-miss collisions by ships comprise a significant risk. Under the background of intelligent transportation, the emergence of technologies such as unmanned driving put forward higher requirements for maritime risk detection models. Previous studies have rarely been able to adaptively estimate the risk of near-miss collisions in different situations, especially for rare but existing encounters. Given this, this paper aims to improve the Vessel collision risk operator (VCRO) and proposes an exponential model of the safety distance in terms of the imbalance of risk assessment in the case of ships meeting close to the safety zone. Then combining the two risk standards set in the ship collision risk operator, and considering the impact of relative speed and relative course on collision risk, the risk detection model is further improved. The simulation results show that the improved ship collision risk assessment model is more applicable and accurate for the detection of collision risk in the open sea.
Analysis of the influence of inductance and capacitance on film bulk acoustic wave filter
Authors: Peng C R , Liu G , Zhong H , Shi Y 
Published: February 2021

Abstract
Film bulk acoustic wave (BAW) filter is a kind of new type filter based on MEMS technology. And it has the advantages of high working frequency, simple manufacturing process, small size, integrating and has become a research hotspot in recent years. Compared with surface acoustic wave filter and ceramic dielectric filter, it has higher operating frequency and Q value. In this paper, the working principle of film bulk acoustic wave filter is briefly analysed, and ADS simulation software is used to further explore the influence of inductance and capacitance on its S parameter.
Atmospheric plasma: a simple way of improving the interface between natural polysaccharides and polyesters
Authors: Carette X , Mincheva R , Herbin M , Noirfalise X , Nguyen T C , Leclere P , Godfroid T , Kerdjoudj H , Jolois O , Boudhifa M , Raquez J 
Published: February 2021

Abstract
In this study, a novel simple and fast method was developed of immobilizing a natural polysaccharide (chitosan) on a polylactide (PLA) surface. In order to overcome the lack of surface adhesion between the chitosan and the PLA due to incompatibility issues, atmospheric pressure plasma was used. The plasma activation was able to modify the PLA surface by generating surface chemistry proper for stabilizing the chitosan layer. The activation of the surface was monitored through water contact angle (WCA) measurements and X-ray photoelectron spectroscopy (XPS). Indeed, the introduction of new functionalities lowers the hydrophobicity of the PLA surface allowing an effective spreading and immobilization of the chitosan layer. The presence of chitosan on the polyester’s surface was proven by Fourier transform infrared spectroscopy (FTIR).
Investigation of the deviation during the information transfer from the prosthetic field to the laboratory scanners
Authors: Galeva H. , Uzunov T. , Stoev Y. , Sofronov Y. , Todorov G. 
Published: February 2021

Abstract
The aim of this work is to investigate the deviations during the first stage of the information transfer from the prosthetic field to the dental laboratory scanners for CAD/CAM technology. The first upper left molar on an artificial acrylic resin dental model was prepared for full metal-ceramic crown according to the standard guidelines for step cut. The prepared prosthetic field was scanned by a high-precision industrial scanner with a 1-mm ruby ball stylus and a digital copy was made. With a standard tray, a two-phase two-stage silicon (A-silicone Zhermack hydrorise putty and light body) impression from the acrylic model was taken following the technology recommended by the manufacturer. The impression was powdered with dental stone type IV and a stone model was created 1 h after impression, the time delay taking place ordinarily in dental practice. Using the same measurement methods, the stone model’s surfaces were digitized. Both digital models were compared using the acrylic resin dental model as a reference. The results on the deviation during the transfer of information between the prosthetic field and the stone model represent the first level of inaccuracy in the CAD/CAM processing technology. The difference in the alteration of each dimension according to the reference and the stone model is not more than 20 μm in shrinkage or expansion direction. Thus, the widely used approach for information transfer using stone models from the prosthetic field to laboratory scanner for CAD/CAM technology could be considered as relevant with an accuracy of about ±10 μm. If the silicon impression is performed carefully, the stone models are sufficiently accurate representations of the prosthetic field and their digitalization in the dental laboratory is a reliable starting point for the CAD/CAM technology.
Optically-controlled density of alkali atom vapor for biomagnetic sensing applications
Authors: Tsvetkov S , Gateva S 
Published: February 2021

Abstract
Biomagnetic sensing is a powerful non-invasive tool for sensing the extremely small magnetic signals of living organisms. In recent years, the efforts to achieve higher resolution has brought about a demand for novel methods of increasing this tool’s sensitivity and further its miniaturization. In this paper, we present our studies on the optical control of the atomic vapor density in antirelaxation coated cells for application in optical magnetometry. A special system for homogeneous illumination of the cell walls is used to increase the atomic density, avoid the deposition of alkali atoms on the cell walls and reduce the coating deterioration.
Synthesis and characterization of polypyrrole-coated iron oxide nanoparticles
Authors: Lett J Anita , Sagadevan Suresh , Alshahateet Solhe F , Murugan Baranya , Jasni Ainil Hawa , Fatimah Is , Hossain M A Motalib , Mohammad Faruq , Oh Won Chun 
Published: February 2021

Abstract
Conducting polymers are gaining importance in recent years for their remarkable electrical and ionic properties and so, in order to further improve the fundamental properties, they are being integrated with iron oxide (Fe3O4) nanoparticles (NPs). Therefore, in the present study, polypyrrole (PPy) doped with iron oxide NPs to form PPy@Fe3O4 nanocomposite by adopting a simple chemical precipitation method of in situ polymerization. The various spectroscopic (UV–vis, FTIR, Raman, XRD, and XPS), and electron microscopic (FESEM and HRTEM) analysis were employed to study the effects of Fe3O4 NPs onto the polymer mixture. The analysis of results revealed the successful doping of Fe3O4 NPs onto the PPy polymer and also, the Raman spectral studies confirmed not only for the stabilization of doped nanocomposites in its polaronic form but also prevented from the auxiliary oxidation of polymer.
Research on the preparation method, microstructure and performance of hard silver plated/Cu-Cr0.6-Zr0.02 alloy contact
Authors: Shao Xinghai , Yang Qianqian , Liu Yuan , Zhao Molin , Wang Biao , Xu Yu , Wang Yao , Zhang Changle , Cao Lei 
Published: February 2021

Abstract
This paper developed a new type of disconnect switch contact with high-conductivity, oxidation resistance and wear resistance. Contact material and preparation were researched. The Cu–Cr–Zr alloy was prepared by vacuum induction melting, then the plate was obtained after rolling and aging strengthening. Contact sample was formed by die stamping, at last, a wear-resistant coating/Cu–Cr–Zr alloy switch contact was manufactured, after the silver antimony alloy hard coating was electroplated on the surface. In order to further study the Cu–Cr–Zr alloy and hard silver coating of the contact, microstructure analysis and performance testing are carried out. A large number of nano-sized pure Cr phases were found to exist in the Cu–Cr–Zr alloy matrix, and the material conductivity was 76.3% IACS. Compared with T2 copper, its mechanical properties and oxidation resistance were significantly improved, which helped to delay the corrosion progress of the substrate after the coating disappeared. The hard silver coating contains 1% of the alloy element Sb. Compared with the silver coating, its wear resistance was increased by 135.30%. Cu–Cr–Zr alloy and hard silver plating technology are effective for improving strength, corrosion resistance and wear resistance of contact.
In-line MRI-LINAC depth dose measurements using an in-house plastic scintillation dosimeter
Authors: Madden Levi , Roberts Natalia , Jelen Urszula , Dong Bin , Holloway Lois , Metcalfe Peter , Rosenfeld Anatoly , Li Enbang 
Published: February 2021

Abstract
Plastic scintillation dosimeters (PSDs) have many properties that make them desirable for relative dosimetry with MRI-LINACs. An in-house PSD, Farmer ionisation chamber and Gafchromic EBT3 film were used to measure central axis percentage depth dose distributions (PDDs) at the Australian MRI-LINAC Mean errors were calculated between each detector’s responses, where the in-house PSD was on average within 0.7% of the Farmer chamber and 1.4% of film, while the Farmer chamber and film were on average within 1.1% of each other. However, the PSD systematically over-estimated the dose as depth increased, approaching a maximum overestimation of the order of 3.5% for the smallest field size measured. This trend was statistically insignificant for all other field sizes measured; further investigation is required to determine the source of this effect. The calculated values of mean absolute error are comparable to the those of trusted dosimeters reported in the literature. These mean absolute errors, and the ubiquity of desirable dosimetric qualities inherent to PSDs suggest that PSDs in general are accurate for relative dosimetry with the MRI-LINAC. Further investigation is required into the source of the reported systematic trends dependent on field-size and depth of measurement.
Polydisperse inter-electrode plasma of Pd nanoclusters as a random cavity for x-ray spontaneous emission bursts
Authors: Smetanin I V , Kurilenkov Yu K , Oginov A V , Tarakanov V P , Samoylov I S 
Published: February 2021

Abstract
It is demonstrated experimentally that polydisperse Pd plasma of low energy (∼1 J) nanosecond vacuum discharge operating in a virtual cathode regime becomes an effective stochastic cavity in hard x-ray domain. A diffusion model of stochastic propagation of spontaneous x-ray radiation in the volume of randomly located reflecting clusters is developed also. The model provides qualitative explanation of both the experimentally observed effects of high-intensity bursts and partial ‘trapping’ of x-ray radiation. The x-ray burst emerges when photons are stored inside the plasma volume followed by instant release at the end of the discharge while the trapping regime corresponds to the slow developing x-ray diffusion with the characteristic time larger than the discharge duration. The results obtained are compared qualitatively with well-known concept of Letokhov’s random laser.
Random walks and community detection in hypergraphs
Authors: Carletti Timoteo , Fanelli Duccio , Lambiotte Renaud 
Published: February 2021

Abstract
We propose a one-parameter family of random walk processes on hypergraphs, where a parameter biases the dynamics of the walker towards hyperedges of low or high cardinality. We show that for each value of the parameter, the resulting process defines its own hypergraph projection on a weighted network. We then explore the differences between them by considering the community structure associated to each random walk process. To do so, we adapt the Markov stability framework to hypergraphs and test it on artificial and real-world hypergraphs.
Dysphagia due to necrotizing otitis externa
Authors: Dwivedi Rajesh , Rasquinha Melroy , Harwood Rowan 
Published: February 2021

Abstract
An 88-year-old man presented with delirium, and subsequently developed hoarseness and oropharyngeal dysphagia. This was due to skull-based osteomyelitis from necrotizing otitis externa (NOE), causing lower cranial nerve (X, XII) palsies and venous sinus thrombosis. Diagnosis was delayed as the patient reported no otalgia, had an almost normal looking external auditory canal and was not diabetic. He deteriorated and died despite intravenous antibiotics. We need a high index of suspicion for NOE and its complications in patients presenting with otolaryngeal symptoms.
The Effects of Placebo and Moderate Dose Alcohol on Attentional Bias, Inhibitory Control and Subjective Craving
Authors: McNeill Adam M , Monk Rebecca L , Qureshi Adam W , Litchfield Damien , Heim Derek 
Published: February 2021

AbstractAimsPrevious research indicates that acute alcohol intoxication and placebo can inhibit people’s control over consumption behaviour and heighten attentional bias (AB) towards alcohol-related stimuli and craving. We designed a study to disentangle anticipated from pharmacological effects of alcohol in order to gain a clearer view of their relative contributions to alcohol consumption.MethodsIn a within-participants design (moderate alcohol dose, placebo and control), and over a minimum 2-week period, participants completed a battery of questionnaires and cognitive tasks, followed by a bogus taste task to measure ad libitum consumption.ResultsBoth alcohol preload and placebo resulted in cognitive and psychological changes, including impaired inhibitory control, heightened AB and craving. However, ad libitum consumption only increased following alcohol and not placebo. Furthermore, inhibitory control impairments did not mediate the relationship between initial intoxication and ad libitum consumption, and findings indicate that increases in craving may mediate this association.ConclusionPsychological processes such as craving may be more important in driving consummatory behaviour relative to transient changes in cognitive processes, such as inhibitory control.
Long-Term Effects of Platelet-Rich Fibrin on Fat Graft Survival and Their Optimal Mixing Ratio
Authors: Yu Panxi , Yang Xiaonan , Zhai Zhen , Gao Qiuni , Yang Zhenyu , Qi Zuoliang 
Published: February 2021

Abstract

Background
Platelet-rich fibrin (PRF) can promote fat graft survival, but the reported mixing ratio of PRF to fat ranges from 1:25 to 1:2, lacking a clear standard for clinical application.

Objectives
The authors sought to explore the long-term effects of PRF on grafted fat and their optimal mixing ratio.

Methods
Nude mice were randomly divided into a control group (receiving subcutaneous injection of fat granules) and 4 PRF groups (receiving subcutaneous injection of PRF and fat granules at volume ratios of 1:5, 1:10, 1:15, and 1:20, respectively). The graft samples (n = 12) were obtained in weeks 4, 8, and 12 to (1) calculate retention rates; (2) evaluate gene and protein expression of vascular endothelial growth factor A (VEGF-A), peroxisome proliferator-activated receptor-γ (PPAR-γ), type I collagen A1 (COL1-A1), and B-cell lymphoma-2 associated X protein (BAX); (3) perform hematoxylin and eosin, Masson’s trichrome, α-smooth muscle action, and periplipin-1 stainings; and (4) count the microvessels and viable adipocytes.

Results
Compared with the control group, PRF groups had higher retention rates, a higher gene/protein expression of VEGF-A, a lower gene/protein expression of COL1-A1 and BAX, less fibrosis, and more microvessels and viable adipocytes. Group 1:10 was superior to other groups in terms of retention rates and other evaluation indexes. The expression of PPAR-γ did not significantly differ among groups.

Conclusions
PRF may not play a long-term effect on adipogenesis, but it can still promote fat graft survival through facilitating vascularization, regulating collagen production, and inhibiting apoptosis. PRF can achieve the best promoting effect when the mixing ratio of PRF to fat is 1:10, which is recommended as the optimal ratio for clinical application.
Regulation of gene expression in the bovine blastocyst by colony-stimulating factor 2 is disrupted by CRISPR/Cas9-mediated deletion ofCSF2RA
Authors: Xiao Yao , Uh Kyungjun , Negrón-Pérez Veronica M , Haines Hannah , Lee Kiho , Hansen Peter J 
Published: February 2021

AbstractColony-stimulating factor 2 (CSF2) functions in the reproductive tract to modulate the function of the preimplantation embryo. The β subunit of the CSF2 receptor (CSF2RB) is not expressed in the embryo, and signal transduction is therefore different than for myeloid cells where the receptor is composed of α (CSF2RA) and β subunits. Here, we produced embryos in which exons 5 and 6 of CSF2RA were disrupted using the CRISPR/Cas 9 system to test whether CSF2RA signaling was essential for actions of CSF2 in the bovine embryo. Wild-type and CSF2RA knockout embryos were treated with 10 ng/mL CSF2 or vehicle at day 5 of development. Blastocysts were harvested at day 8 to determine transcript abundance of 90 genes by real-time polymerase chain reaction (PCR). Responses in female blastocysts were examined separately from male blastocysts because actions of CSF2 are sex-dependent. For wild-type embryos, CSF2 altered expression of 10 genes in females and 20 in males. Only three genes were affected by CSF2 in a similar manner for both sexes. Disruption of CSF2RA prevented the effect of CSF2 on expression for 9 of 10 CSF2-regulated genes in females and 19 of 20 genes in males. The results confirm the importance of CSF2RA for regulation of gene expression by CSF2 in the blastocyst.