bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mathematical model of a radial sliding bearing with a porous layer on its operating surface with a low-melting metal coating on shaft surface
Authors: Akhverdiev K S , Bolgova E A , Mukutadze M A , Vasilenko V V 
Published: February 2021

Abstract
The paper considers the steady flow of a liquid lubricant and a melt of a low-melting metal coating of the shaft surface, which have viscous rheological properties in the operating clearance of an endless radial sliding bearing, as well as in the body of the porous coating of the surface of bearing bush. In order to solve this problem, the authors used the equation of the movement of viscous lubricant for a thin layer, the equation of continuity and also the equation describing the radius of the molten contour of the fusible coating of the shaft surface, taking into account the rate of dissipation of mechanical energy. Having averaged the acceleration of the movement of the liquid lubricant in the operating clearance, the authors obtained the dependence for the contour of the molten coating of the shaft surface. As a result of the integration of the obtained dependence, the expression was found that allowed solving the function characterizing the contour of the molten surface of the coating by the method of successive approximations. Using the well-known method of finding an exact self-modal solution, the velocity field and pressure in the lubricating and porous layer, as well as the load capacity and friction force, were found. On the basis of the performed theoretical studies, the experimental study was carried out taking into account the parameters characterizing the melt of a low-melting metal coating, as well as a porous coating on the surface of the bearing bush and the rheological properties of a viscous lubricant. As a result, the original expression was obtained for the calculation of the load capacity of a radial bearing and the magnitude of the friction force in the range under the following loading conditions v=0.5÷3 m/s, σ=2÷7 MPa. The research results can be used in mechanical engineering, aircraft construction, instrument engineering, where the supply of lubricant is associated with great difficulties.
Automation of the procedure for assessing the quality of transport service for the population in the conditions of digitalization of the railway transportation system
Authors: Bulokhova T A , Olentsevich V A , Konyukhov V Yu , Lysenko D A 
Published: February 2021

Abstract
The Strategic Program for the Development of Railway Transport until 2030 focuses on the development of a customer-oriented approach as one of the conditions for the company’s competitiveness. The customer focus is one of the elements of anti-crisis management of transport systems, it provides additional opportunities, especially when the volume of traffic decreases, when it is necessary to fight for attracting customers. A customer-oriented approach is closely related to the quality of the organization of transport services for passengers, which is certainly impossible without the use of modern automated technologies. Thus, a modern passenger is characterized by mobility and the habit of being online, in connection with which the passenger infrastructure and rolling stock must be provided with equipment and software that allows the passenger to remain in the familiar information environment.
Automation of preproduction processes for high-precision small-sized parts on CNC machines
Authors: Karlina Yu I , Kargapoltsev S K , Gozbenko V E , Leonovich D S , Karlina A I 
Published: February 2021

Abstract
The theoretical basis of the processes of preparation for the production of high-precision small-sized parts of coaxial radio components on CNC machines allows you to supplement the existing CAD / CAE / CAM with fragments of algorithmizing. To integrate the stages of technological preparation for the production of high-precision small-sized parts of coaxial radio components on CNC machines, a study of the features of the production of parts and the standard functionality of CAM systems was carried out. A classification of these parts by the type of equipment, types, serial production, variable parameters within the type, materials, and tools has been developed. The possibilities of the extensibility of the functions of CAM systems, the existing methods of creating and verifying control programs are considered. An example of a successful expansion of the functionality of a standard CAM system in the radio-electronic industry is given - a module for increasing machining accuracy with a constant cutting mode by optimizing the mutual positioning of the tool and the workpiece. Requirements have been developed for the creation of a specialized combined method for verification of control programs using all existing verification capabilities and minimal use of debugging and verification directly on the machine with the maintenance of reference books of worked processing modes in which the number and size of burrs are minimal, as well as a library of control programs equipped with a search system for the parameters of the difference in the execution of parts.
Studying the dynamics of contact interactions during machining based on a system of nonlinear piecewise linear differential equations
Authors: Vasilkov D V , Alexandrov A S , Golikova V V , Kochina T B 
Published: February 2021

Abstract
When manufacturing parts for thermal control systems for operation in especially difficult conditions of the North and in spacecraft, titanium and complex alloyed alloys are used. They are subject to increased quality requirements. They are achieved through simulation modeling. The solution is based on a dynamic model in which the contact interaction between the tool flank and the workpiece is differentiated. The process of contact interaction is considered as two-phase in the form of a sequence of states of adhesion and sliding. In the space of state variables, a system of nonlinear differential equations of piecewise linear type is constructed based on a set of rheological models. Based on this model, simulation modeling was carried out in the form of a computational experiment. A periodic solution is obtained which is formed as a result of switching the sliding and adhesion phases. In the graphs presented in the paper, the transition from the adhesion phase to the sliding phase is accompanied by a surge in displacement. In this case, in the phase portrait, the phase trajectory reaches the limit cycle with a limited amplitude. At the moment of transition from the adhesion phase to the sliding phase, a characteristic deviation of the phase trajectory from the limit cycle with an increased amplitude is observed, followed by a return to the limit cycle. With a wide variation in cutting speed, the conditions for technical stability are determined. During the simulation, a dynamic manifestation of the formation of chip elements was found, which did not have a serious impact on the nature of dynamic processes. The results obtained make it possible to study the dynamics of contact interactions during cutting in the framework of nonlinear dynamic models. This makes it possible to assess the level of vibration amplitudes and determine the regulated parameters of processing accuracy and surface roughness of manufactured products.
Identification of problem parts made by longitudinal stretching when compensating for springing
Authors: Mironenko V V , Govorkov A S 
Published: February 2021

Abstract
The paper considers problem related to the compensation of springing of parts produced by longitudinal stretching. It proposes the method of eliminating this effect by replacing the shaping method with transverse stretching. A finite element simulation of transverse stretching for the selected element produced by longitudinal stretching was carried out. The analysis of results revealed elimination of negative phenomenon of springing. After changing the scheme, the nature of the workpiece movement during springing became classic. The paper describes the procedure for the geometry of the element to determine problems in the compensation of fitting related to springing. The method takes into account the geometric parameters of the curvature radii of the element in different directions and the relations between them. The criteria for identifying problem parts are presented.
Assessment of strength of elements produced using 3D printing technology
Authors: Perelygina A Yu , Raspopina V B , Rudykh A V , Grigorov P A 
Published: February 2021

Abstract
In some cases, 3D-printed products must be able to resist the stresses caused by their functionality. The design of bionic artificial hand is considered as a construction made using 3D printing technology, the strength of which must be assessed. The artificial limb is made using extrusion plastic printing. In order to assess the strength of the artificial limb, the experimental study of the samples made using 3D printing technology was carried out. The influence of three parameters on the strength characteristics of the samples was studied: the percentage of filling, the filling pattern and the direction of the material layering in the sample.
Appropriate use of dissolved gas energy in fields at the final stage of development
Authors: Yusupova L F , Almukhametova E M , Nosirov D S , Safiullina A R 
Published: February 2021

Abstract
In order to improve the development of fields at a later stage, this article considered the use of water-gas repression together with the dissolved gas energy. The theoretical basis of the study is based on the application of the method of physical modeling of oil displacement by water. As a result, it was found that waterflooding would be more effective when such an activity is carried out in the early stages of development. Waterflooding can also be effective in old, depleted fields with shallow depths of oil-bearing horizons. The article states that in flooded deposits, where the reservoir pressure did not drop below the bubble point pressure, it is advisable to reduce the reservoir pressure to the bubble point pressure (to carry out forced withdrawal). After that, water injection should be resumed with 30-50% compensation. It has been established that in order to increase the efficiency of the development of fields developed in the dissolved gas mode, waterflooding must be started at a reservoir pressure that is 30–70% less than the bubble point pressure. The best option for the development of such deposits is the presence of active edge waters. If they are absent, it is advisable to end water in the aquifer with compensation of withdrawals from 20 to 40% after the start of gas extraction from oil.
Micro-electrode channel guide (µECG) technology: an online method for continuous electrical recording in a human beating heart-on-chip
Authors: Visone Roberta , Ugolini Giovanni S , Cruz-Moreira Daniela , Marzorati Simona , Piazza Stefano , Pesenti Enrico , Redaelli Alberto , Moretti Matteo , Occhetta Paola , Rasponi Marco 
Published: February 2021

Abstract
Cardiac toxicity still represents a common adverse outcome causing drug attrition and post-marketing withdrawal. The development of relevant in vitro models resembling the human heart recently opened the path towards a more accurate detection of drug-induced human cardiac toxicity early in the drug development process. Organs-on-chip have been proposed as promising tools to recapitulate in vitro the key aspects of the in vivo cardiac physiology and to provide a means to directly analyze functional readouts. In this scenario, a new device capable of continuous monitoring of electrophysiological signals from functional in vitro human hearts-on-chip is here presented. The development of cardiac microtissues was achieved through a recently published method to control the mechanical environment, while the introduction of a technology consisting in micro-electrode coaxial guides allowed to conduct direct and non-destructive electrophysiology studies. The generated human cardiac microtissues exhibited synchronous spontaneous beating, as demonstrated by multi-point and continuous acquisition of cardiac field potential, and expression of relevant genes encoding for cardiac ion-channels. A proof-of-concept pharmacological validation on three drugs proved the proposed model to potentially be a powerful tool to evaluate functional cardiac toxicity.
Neural ordinary differential equation and holographic quantum chromodynamics
Authors: Hashimoto Koji , Hu Hong-Ye , You Yi-Zhuang 
Published: February 2021

Abstract
The neural ordinary differential equation (neural ODE) is a novel machine learning architecture whose weights are smooth functions of the continuous depth. We apply the neural ODE to holographic QCD by regarding the weight functions as a bulk metric, and train the machine with lattice QCD data of chiral condensate at finite temperature. The machine finds consistent bulk geometry at various values of temperature and discovers the emergent black hole horizon in the holographic bulk automatically. The holographic Wilson loops calculated with the emergent machine-learned bulk spacetime have consistent temperature dependence of confinement and Debye-screening behavior. In machine learning models with physically interpretable weights, the neural ODE frees us from discretization artifact leading to difficult ingenuity of hyperparameters, and improves numerical accuracy to make the model more trustworthy.
A reinforcement learning application of a guided Monte Carlo Tree Search algorithm for beam orientation selection in radiation therapy
Authors: Sadeghnejad-Barkousaraie Azar , Bohara Gyanendra , Jiang Steve , Nguyen Dan 
Published: February 2021

Abstract
Current beam orientation optimization algorithms for radiotherapy, such as column generation (CG), are typically heuristic or greedy in nature because of the size of the combinatorial problem, which leads to suboptimal solutions. We propose a reinforcement learning strategy using a Monte Carlo Tree Search (MCTS) that can find a better beam orientation set in less time than CG. We utilize a reinforcement learning structure involving a supervised learning network to guide the MCTS and to explore the decision space of beam orientation selection problems. We previously trained a deep neural network (DNN) that takes in the patient anatomy, organ weights, and current beams, then approximates beam fitness values to indicate the next best beam to add. Here, we use this DNN to probabilistically guide the traversal of the branches of the Monte Carlo decision tree to add a new beam to the plan. To assess the feasibility of the algorithm, we used a test set of 13 prostate cancer patients, distinct from the 57 patients originally used to train and validate the DNN, to solve five-beam plans. To show the strength of the guided MCTS (GTS) compared to other search methods, we also provided the performances of Guided Search, Uniform Tree Search and Random Search algorithms. On average, GTS outperformed all the other methods. It found a better solution than CG in 237 s on average, compared to 360 s for CG, and outperformed all other methods in finding a solution with a lower objective function value in less than 1000 s. Using our GTS method, we could maintain planning target volume (PTV) coverage within 1% error similar to CG, while reducing the organ-at-risk mean dose for body, rectum, left and right femoral heads; the mean dose to bladder was 1% higher with GTS than with CG.
Associations of Lifestyle and Anthropometric Factors With the Risk of Herpes Zoster: A Nationwide Population-Based Cohort Study
Authors: Schmidt Sigrun A J , Sørensen Henrik Toft , Langan Sinéad M , Vestergaard Mogens 
Published: February 2021

AbstractThe role of lifestyle in development of herpes zoster remains unclear. We examined whether smoking status, alcohol consumption, body mass index, or physical activity were associated with zoster risk. We followed a population-based cohort of 101,894 respondents to the 2010 Danish National Health Survey (baseline, May 1, 2010) until zoster diagnosis, death, emigration, or July 1, 2014, whichever occurred first. We computed hazard ratios for zoster associated with each exposure, using Cox regression with age as the time scale and adjusting for potential confounders. Compared with never smokers, hazards for zoster were increased in former smokers (1.17, 95% confidence interval (CI): 1.06, 1.30), but not in current smokers (1.00, 95% CI: 0.89, 1.13). Compared with low-risk alcohol consumption, neither intermediate-risk (0.95, 95% CI: 0.84, 1.07) nor high-risk alcohol consumption (0.99, 95% CI: 0.85, 1.15) was associated with zoster. We also found no increased hazard associated with weekly binge drinking versus not (0.93, 95% CI: 0.77, 1.11). Risk of zoster varied little by body mass index (referent = normal weight) and physical activity levels (referent = light level), with hazard ratios between 0.96 and 1.08. We observed no dose-response association between the exposures and zoster. The examined lifestyle and anthropometric factors thus were not risk factors for zoster.
A General Propensity Score for Signal Identification Using Tree-Based Scan Statistics
Authors: Wang Shirley V , Maro Judith C , Gagne Joshua J , Patorno Elisabetta , Kattinakere Sushama , Stojanovic Danijela , Eworuke Efe , Baro Elande , Ouellet-Hellstrom Rita , Nguyen Michael , Ma Yong , Dashevsky Inna , Cole David , DeLuccia Sandra , Hansbury Aaron , Pestine Ella , Kulldorff Martin 
Published: February 2021

Abstract
The tree-based scan statistic (TreeScan; Martin Kulldorff, Harvard Medical School, Boston, Massachusetts) is a data-mining method that adjusts for multiple testing of correlated hypotheses when screening thousands of potential adverse events for signal identification. Simulation has demonstrated the promise of TreeScan with a propensity score (PS)-matched cohort design. However, it is unclear which variables to include in a PS for applied signal identification studies to simultaneously adjust for confounding across potential outcomes. We selected 4 pairs of medications with well-understood safety profiles. For each pair, we evaluated 5 candidate PSs with different combinations of 1) predefined general covariates (comorbidity, frailty, utilization), 2) empirically selected (data-driven) covariates, and 3) covariates tailored to the drug pair. For each pair, statistical alerting patterns were similar with alternative PSs (≤11 alerts in 7,996 outcomes scanned). Inclusion of covariates tailored to exposure did not appreciably affect screening results. Inclusion of empirically selected covariates can provide better proxy coverage for confounders but can also decrease statistical power. Unlike tailored covariates, empirical and predefined general covariates can be applied “out of the box” for signal identification. The choice of PS depends on the level of concern about residual confounding versus loss of power. Potential signals should be followed by pharmacoepidemiologic assessment where confounding control is tailored to the specific outcome(s) under investigation.
Age and Body Mass Index Affect Patient Satisfaction Following Reduction Mammoplasty: A Multicenter Study Using BREAST-Q
Authors: Jørgensen Mads Gustaf , Albertsdottir Elin , Dalaei Farima , Hesselfeldt-Nielsen Jørgen , Schmidt Volker-Jürgen , Sørensen Jens Ahm , Toyserkani Navid Mohamadpour 
Published: February 2021

Abstract

Background
Reduction mammoplasty effectively improves quality of life for women with macromastia. However, little is known whether surgical- or patient-related factors affect satisfaction.

Objective
The authors sought to investigate factors associated with altered patient satisfaction following reduction mammoplasty.

Methods
A cross-section study was performed by sending the BREAST-Q Reduction module to all patients who had undergone reduction mammoplasty between January 2009 and December 2018 at 2 tertiary Danish hospitals. Demographics and pre-, peri-, and postoperative details were gathered from electronic medical records.

Results
A total of 393 patients returned the questionnaire and were eligible for the study. Increasing age at the time of surgery was associated with higher satisfaction with breasts nipples, headache, psychosocial well-being, and outcome. Increased body mass index at the time of surgery negatively affected satisfaction with breasts and psychosocial well-being. Increase in body mass index after surgery was further associated with lower satisfaction with breasts, nipples, sexual well-being, and more pain in the breast area. Postoperative scar revision and wound infection was more common following inferior pedicle technique than superomedial technique and negatively affected satisfaction with outcome and pain in the breast area.

Conclusions
Patients should be motivated to optimize their weight prior to reduction mammoplasty to achieve optimal satisfaction. Age was associated with improved patient satisfaction, which should considered when operating on younger patients. Postoperative complications affect patient satisfaction, and the superomedial technique seems to be a better choice than the inferior pedicle technique in medium-large breasts.

Level of Evidence: 4
Asian Upper Blepharoplasty in Women: A Comprehensive Approach for a Natural and Aesthetically Pleasing Outcome
Authors: Wang Chunmei , Mei Xiaoxia , Pu Lee L Q 
Published: February 2021

Abstract

Background
Asian upper blepharoplasty is the most popular cosmetic procedure for Asian women. However, there is no standardized approach to this procedure and suboptimal results are still common.

Objectives
The aim of this article was to describe a comprehensive approach to Asian upper blepharoplasty in women and report the clinical outcomes obtained with this approach.

Methods
The comprehensive approach described here for Asian upper blepharoplasty in women includes: (1) determining the height and length of the upper eyelid skin crease; (2) creating a more optimal anatomy of the upper eyelid by removing excess eyelid skin, a portion of the orbicularis oculi muscle, and septal fat; (3) reconstructing the desired anatomic structures of the upper eyelid skin crease through plication of the levator aponeurosis, if necessary, and closure of the upper eyelid skin incision through the septum and the mobile portion of the levator aponeurosis; (4) adding a medial epicanthoplasty if needed to enhance final cosmetic results.

Results
Over a 5-year period, 332 Asian women underwent upper blepharoplasty for creation of double eyelids, or conversion from less visible to more ideal double eyelids, with the above comprehensive approach. There were no surgical complications postoperatively and 326 patients (98.2%) rated their outcome satisfactory over a 5-year follow-up. Only 6 patients (1.8%) required surgical revision for asymmetry or suboptimal shape of the upper eyelid.

Conclusions
The comprehensive approach to Asian upper blepharoplasty described here can be used for Asian women and produces a natural and aesthetically pleasing outcome and low revision rates.

Level of Evidence: 4