bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fracture toughness of hot rolled pure magnesium: Correlation with microstructure and texture
Authors: C.Prakash Gautam , Bar H.N. , Sivaprasad S. , Tarafder S. , Biswas Somjeet 
Published: April 2021

Abstract
Pure magnesium possesses high specific strength, and hence it has excellent potential for biodegradable structural bioimplants. Such a load-bearing application requires the material to have sufficient fracture toughness to sustain the presence of undesirable microcracks. In this work, biomedical grade pure magnesium was hot-rolled to obtain equiaxed microstructure with basal texture. Single edge notch bending specimens with a notch along the rolling direction, transverse direction, and 45° to both were prepared. Fatigue pre-cracking was performed, followed by the fracture toughness tests. All the samples show sufficient plasticity during the fracture toughness test to evaluate J
1C
. The characterization was done by electron backscatter diffraction. The influence of initial texture and the strain state on the evolution of twins in the vicinity of the crack path and fracture toughness was comprehended.
Change in intragranular misorientation during stress relaxation in Al-Cu-Mg-Mn alloy subjected to continuous cyclic bending
Authors: Hoshino Takumi , Miura Kouki , Takayama Yoshimasa , Watanabe Hideo 
Published: April 2021

Abstract
Change in intragranular misorientation during stress relaxation in Al-Cu-Mg-Mn (2024) alloy sheet subjected to continuous cyclic bending (CCB) has been investigated by electron back scatter diffraction (EBSD) technique. EBSD analysis revealed that kernel average misorientation (KAM) value was heitened not only in the sheet worked by CCB but also during stress relaxation test. Grain orientation spread (GOS) value, another misorientation parameter, was also calculated and compared with KAM value of each sample. Both of KAM and GOS values varied with four stages about stress and stored strain: (a) unloaded before stress relaxation test (SRT), (b) loaded before SRT, (c) loaded after SRT and (d) unloaded after SRT. Change in KAM value was likely corresponding to sum of applied and residual stresses. Quantitative relationship between increase and decrease in KAM value between the stages was divided into two types according to dynamic restoration mechanisms.
Texture-related biological properties of severely deformed titanium
Authors: Wojtas D , Mzyk A , Kawalko J , Trembecka-Wójciga K , Wierzbanowski K , Imbir G , Marzec M , Maj L , Jarzçbska A , Bieda-Niemiec M , Chulist R , Sztwiertnia K , Pachla W 
Published: April 2021

Abstract
Pure titanium manufactured by hydrostatic extrusion has been investigated with the aim to find the clear origin of superior biological properties observed in the materials processed by various severe plastic deformation techniques. In so doing, physicochemical properties of the surface were characterised as well as protein adsorption tests and cell culture examinations were thoroughly carried out. It has been found that, irrespective of the grain size, the basal planes exposed to the surface favour protein adsorption, whereas it is prismatic planes that experience pronounced cell activity on the surface of hydrostatically extruded titanium substrates. Biological behaviour of severely deformed titanium-based materials should be attributed to crystallographic orientation of grains, chemical composition of the surface as well as the presence of surface irregularities in the form of various nano-peaks or nano-grooves, while the effect of grain size might be of less importance.
3D simulation of texture evolution induced grain coarsening in FCC polycrystals during severe plastic deformation
Authors: Zhang Chi , Toth Laszlo S 
Published: April 2021

Abstract
In the present work, results obtained in 3D polycrystal simulations are reported on the coalescence effect of neighbouring grains due to texture evolution. A 3D cellular automaton model was developed for this purpose, which permits to take into account the effect of topology on coalescence. The grains constituting the polycrystal were divided into voxels to have realistic representations of grain shapes. The Taylor polycrystal plasticity approach was applied to calculate the orientation change for each voxel. When the disorientation angle between neighbour voxels belonging to different grains was less than 5°, the voxel volume was reallocated to the neighbouring grain. For a random initial texture, after a shear strain of 6, the relative volume that was re-assigned between neighbours was 29.7%, which is not negligible. The effect of initial texture and topology was also investigated. The 3D morphologies of some typical coarsening grains were monitored to illustrate the simulation results.
Influence of laser beam scanning strategy in the selective laser melting of 316L steel powder on macrostress
Authors: Isaenkova MG , Yudin A V , Rubanov A E , Osintsev A V , Degadnikova L A 
Published: April 2021

Abstract
The use of selective laser melting (SLM) leads to the formation of a complex material structure with high residual elastic stresses. The work investigates the distribution of macrostresses in SLM samples using five different scanning strategies. The stresses were measured by X-ray method and by recording the change in the shape of the specimens as a result of their separation from the platform using digital correlation image method. The combined use of the two methods provides more reliable results for SLM samples. It is shown that depending on the scanning strategy, the nature and magnitude of macrostresses change which are distributed more isotropically and have a smaller value when using scanning strategies with different directions of the laser beam movement.
A simple model of additive process mechanics for controlling the evolution of stresses in filament-wound cylindrical composites during the manufacturing process
Authors: Parshin D A 
Published: April 2021

Abstract
A relatively simple mathematical model is proposed and developed that allows using additive process mechanics approaches to trace the evolution of technological stress fields in cylindrical composites during their manufacture by slow multi-layer winding of fibre-reinforced material with an arbitrary variation in the pre-tension force and fibre packing density. The constructed closed analytical dependences make it possible to state problems on controlling the distributions of these stresses.
Estimation of the additive and multiplicative error of the standard algorithm of acoustic emission sources linear location
Authors: Makhutov N A , Vasil’ev I E , Chernov D V , Mishchenko I V , Moskovskaia D S 
Published: April 2021

Abstract
The paper deals with the results of the standard acoustic emission (AE) source linear location algorithm, which evaluates the location of developing damage in a steel sample under static load test to destruction. The linear location algorithm error is due to many factors: acquisition threshold of the AE signals and the dispersion properties of recorded signals, in particular, the dependence of the AE signal propagation velocity on its amplitude. According to the test results, the additive error in determining the time difference of arrival (TDA) of the AE signals to the transducers array is 52.8 μs and the average multiplicative error level is 0.67.
Features of accounting machining process influence on fiber reinforced composites characteristics
Authors: Vlasov D D , Tatus’ N A , Polilov A N , Kh Akhmedshin E 
Published: April 2021

Abstract
The results of the experimental study of machining effect on the fiberglass specimens’ tensile strength realization are presented. According to the data obtained, the size of the damaged zone, which does not carry applied loads and reduces the actual net cross-section of the specimen, has been estimated.
Influence of the composition of polymeric materials on the tribological characteristics under abrasive wear
Authors: Prince A N , Biryukov V P 
Published: April 2021

Abstract
The paper presents the results of tribological tests of thermoplastic polyurethanes (TPU), UHMWPE, polypropylene and rubber based on nitrile butadiene rubber (BNR) on fixed silicon carbide and free abrasive. The influence of pressure and sliding speed on the coefficients of friction is shown. For PP2015 polypropylene, the coefficient of friction and mass loss were 0.3-0.35 and 0.003 g, which is 4-10 times lower than for BNR.
Mathematical model of the polymer concrete by fractional calculus with respect to a spatial variable
Authors: Aleroev Temirkhan S , Mahmoud Elsayed I , Elsayed Asmaa M 
Published: April 2021

Abstract
The article presents a solution of the vibration string equation containing the fractional derivative concerning the spatial variable, in which the fractional derivative is defined by Caputo. This model is utilized for characterizing the oscillation mechanical process in a viscoelastic medium. The theoretical solution is presented, and the fractional derivative parameter is determined. We compared the theoretical solution and the experimental data for polymer concrete samples. A sample of the problem of structural mechanics has been considered. This sample allows the demonstration of some advantages of the application of the suggested approach to solve the fractional vibration equation.
Influence of technological load on the stability of synchronous anti-phase motion of the jaws of a vibratory crusher
Authors: Altshul G , Gouskov A , Panovko G 
Published: April 2021

Abstract
Vibratory jaw crushers are based on the effect of self-synchronization of jaws and body, when its elements vibrate with frequencies that are in a rational relationship due to the influence of links already existing in the system. The technological load acting on the jaws of a vibratory crusher during its operation can have a significant effect on which operating mode of the crusher (synchronous antiphase or synchronous inphase) is implemented. This paper investigates the influence of the proposed crushing model on the dynamics of a vibratory jaw crusher. The model takes into account the elastoplastic properties of the rock being crushed and its one-way connection with the jaws. The destruction of the material, its movement along the crushing chamber and the change in the properties of the processed rock as it is crushing has been implemented. Conclusions are made about the influence of the processed rock on the implementation of the crusher operating modes.
Modeling of a vibrating machine with spatial oscillations of the working body
Authors: Lyan I P , Panovko G Y , Shokhin A E 
Published: April 2021

Abstract
In modern industry, vibration technological machines with unbalanced vibration exciters (vibrating conveyors, vibrating screens, vibrating crushers, etc.) are widely used. The variety of vibration technological machines typical schemes leads to a need to take into account the dynamic system features in the mathematical models that are being created. The aim of this work is to create a spatial mathematical model and determine the dynamic system unknown parameters of a vibrating screen experimental sample with two self-synchronizing unbalanced vibration exciters that create the working body spatial motion. The mathematical model motion equations are derived using the Lagrange equations of the second kind. Using the obtained experimental data (natural frequencies and logarithmic damping decrement), the mathematical model mass-geometric parameters and the damping parameters values were calculated. The investigation result is a verified mathematical model of a vibrating screen sample with two self-synchronizing unbalanced vibration exciters.
Nonlinear oscillation modes of double pendulum
Authors: Smirnov A S , Smolnikov B A 
Published: April 2021

Abstract
The article investigates nonlinear oscillations of the double mathematical pendulum having identical parameters of its links and end loads. Approximate solutions in the nonlinear zone are constructed and analyzed on the basis of exact solution in the linear zone. These solutions clearly illustrate the drift of frequencies and modes of double pendulum with increasing oscillation amplitudes. The obtained analytical results are very useful for the synthesis of controlled movement modes of wide range of manipulators and various robotic structures, and they are also necessary for constructing optimal locomotion modes of walking machines and mechanisms. These solutions are also interesting as illustrative examples of nonlinear mechanics in the teaching and engineering practice.
Development of an algorithm for determining the degree of fatigue of a human operator under the influence of vibration
Authors: Tikunova K V , Brysin A N , Mikaeva S A , Soloviev V S 
Published: April 2021

Abstract
The article discusses the issue of selecting methods for studying human muscle fatigue in the operator-joystick system. The article discusses ways to measure potentials from human muscles. The applicability of the chosen method for evaluating the work of the research object is considered. This article provides an overview of the methods for diagnosing muscle fatigue parameters in the operator-joystick system.
Evaluation of the accuracy of the recognition algorithm of an autonomous robotic device to control weeds
Authors: Dyshakov A I , Mirzaev M A 
Published: April 2021

Abstract
The main problem in the agro-industrial sector is the use of harmful herbicides, resulting in some of the weeds becoming more resistant to common herbicides and therefore using more and more powerful and expensive options. To overcome this problem, t is necessary to reduce the amount of herbicide use. The proposed study aims to develop a system that can detect and map weeds and perform mechanically applied spot spraying. The weed detection techniques described in this study include several aspects: imaging, a new algorithm for detecting plants through contour and colour segmentation. The method developed can detect weeds at early stages of growth. Further development of the methods is aimed at solving problems related to complex background without soil treatment, faster image acquisition speed and shorter processing time for spot injection in real time. The results of the experiment show that the proposed hybrid method can be used as a tool for weed control.
Development of a control system for a mobile robot based on Markov processes
Authors: Fedorov A A , Orekhov S Y , Veysman P I , Vasilchuk N Y 
Published: April 2021

Abstract
The purpose of this work is to develop and study a control system for mobile robots based on Markov processes. The paper investigates the adequacy of the control system algorithms based on Markov processes as applied to a mobile tracked robot.
Magnetic memory. Mechanical tests and proposed mechanisms
Authors: Sklemina O Yu , Skvortsov A A , Pshonkin D E , Tsilenko L P 
Published: April 2021

Abstract
The article considers the issue of an attempt to experimentally study the effect of constant magnetic fields on the processes of plastic deformation of aluminum alloys. An analysis of the influence of a magnetic field on the creep of an Al alloy with iron inclusions is presented. Estimates of the supposed mechanisms of the influence of the magnetic field on the creep processes are given.
Urates of colubroid snakes are different from those of boids and pythonids
Authors: Thornton Alyssa M , Schuett Gordon W , Swift Jennifer A 
Published: April 2021

AbstractUricotelic species, such as squamate reptiles, birds and insects, effectively eliminate nitrogen as uric acid in a solid form commonly called urates. Observations made over a decade suggested that the voided urates produced by colubroids (modern snake species) exhibit remarkable differences from those of boids and pythons (ancient snake species). Here, we compare the urates generated by eight captive snake species fed the same diet. Although all fresh urates were wet at the time of excretion, those produced by modern snakes dried to a powdery solid, whereas those of ancient species dried to a rock-hard mass that was tightly adherent to surfaces. Powder X-ray diffraction and infrared spectroscopy analyses performed on voided urates produced by five modern and three ancient snakes confirmed their underlying chemical and structural differences. Urates excreted by ancient snakes were amorphous uric acid, whereas urates from modern snakes consisted primarily of ammonium acid urate, with some uric acid dihydrate. These compositional differences indicate that snakes have more than one mechanism to manage nitrogenous waste. Why different species use different nitrogen-handling pathways is not yet known, but the answer might be related to key differences in metabolism, physiology or, in the case of ancient snakes, the potential use of urates in social communication.
Acceptance and Perceived Control are Independently Associated With Quality of Life in Inflammatory Bowel Disease: Introduction of a New Segmentation Model
Authors: van Erp Liselot W , van Gerven Jop , Bloem Sjaak , Groenen Marcel J M , Wahab Peter J 
Published: April 2021

Abstract

Background and Aims
Segmentation of patients based on psychological determinants of subjective health may provide new ways to personalized care. The cross-disease segmentation model developed by Bloem & Stalpers discriminates patients based on disease acceptance and perceived control. We aimed to validate the segmentation model, compare segments and evaluate whether segments independently correlate with quality of life in inflammatory bowel disease [IBD].

Methods
A cross-sectional study of adult IBD patients was performed with questionnaires on quality of life [32-item inflammatory bowel disease questionnaire], acceptance and perceived control [six items with 7-point Likert scale]. Four segments were formed [cut-off &gt; 5]: [I] high acceptance, high control; [II] high acceptance, low control [III]; low acceptance, high control and; [IV] low acceptance, low control.

Results
We included 686 patients. The acceptance and perceived control scales were unidimensionally structured and internally consistent. Segments differed significantly in age, smoking behaviour, diagnosis, disease duration, extra-intestinal manifestations, IBD medication, clinical disease activity and quality of life. High acceptance (standardized beta coefficient [ß] 0.25, p &lt; 0.001), high perceived control [ß 0.12, p &lt; 0.001] or both [ß 0.53, p &lt; 0.001], were associated with a significantly better health-related quality of life compared with low acceptance and low perceived control. Sociodemographic and clinical factors explained 25% of the variance in quality of life. The explained variance significantly increased to 45% when the patients’ segment was added to the model [ΔR2 20%, p &lt; 0.001].

Conclusions
The segmentation model based on disease acceptance and perceived control is valid in IBD patients and discriminates different segments that correlate independently with quality of life. This may open new strategies for patient care.
18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging in atrial fibrillation: a pilot prospective study
Authors: Xie Boqia , Chen Bi-Xi , Nanna Michele , Wu Jiao-Yan , Zhou Yang , Shi Liang , Wang Yanjiang , Zeng Lijun , Wang Yuetao , Yang Xing , Liu Xingpeng , Yang Min-Fu 
Published: April 2021

Abstract

Aims
This prospective study explored relevant factors and clinical significance of atrial 18F-fluorodeoxyglucose (FDG) uptake in patients with atrial fibrillation (AF).

Methods and results
One hundred AF patients underwent baseline FDG imaging prior to radiofrequency catheter ablation (RFCA). Of those, 30 subjects underwent additional FDG imaging at 3 months post-RFCA. Voltage mapping of the left atrium was analysed as a voltage score. Patients who received RFCA were followed for 26 months (17–31 months) to assess recurrence. At baseline FDG imaging, 74% of patients with persistent AF (PsAF) and 24% of patients with paroxysmal AF showed increased atrial FDG uptake. The prevalence was higher in the right atrium (49%) than in the left atrium (15%, P &lt; 0.001) or left atrial appendage (21%, P &lt; 0.001). Multivariate analysis demonstrated that PsAF and elevated B-type natriuretic peptide (BNP) were related to enhanced right atrial (RA) activity, and increased epicardial adipose tissue (EAT) activity was predictive of left atrial (LA) activity. LA activity was inversely associated with voltage score, while increased FDG uptake in the right atrium was predictive of successful AF termination by RFCA. Atrial FDG activities decreased significantly post-RFCA, but none of the FDG parameters were predictive of AF recurrence.

Conclusions
Enhanced RA activity was associated with elevated BNP level, whereas LA activity was related to the increased activity of EAT and inversely correlated with LA fibrosis. Increased RA activity was predictive of successful AF termination by RFCA in PsAF patients.
A Caenorhabditis elegans Pheromone Antagonizes Volatile Anesthetic Action Through a Go-Coupled Pathway
Authors: van Swinderen Bruno , Metz Laura B , Shebester Laynie D , Crowder C Michael 
Published: April 2021

Abstract
Volatile anesthetics (VAs) disrupt nervous system function by an ill-defined mechanism with no known specific antagonists. During the course of characterizing the response of the nematode C. elegans to VAs, we discovered that a C. elegans pheromone antagonizes the VA halothane. Acute exposure to pheromone rendered wild-type C. elegans resistant to clinical concentrations of halothane, increasing the EC50 from 0.43 ± 0.03 to 0.90 ± 0.02. C. elegans mutants that disrupt the function of sensory neurons required for the action of the previously characterized dauer pheromone blocked pheromone-induced resistance (Pir) to halothane. Pheromone preparations from loss-of-function mutants of daf-22, a gene required for dauer pheromone production, lacked the halothane-resistance activity, suggesting that dauer and Pir pheromone are identical. However, the pathways for pheromone’s effects on dauer formation and VA action were not identical. Not all mutations that alter dauer formation affected the Pir phenotype. Further, mutations in genes not known to be involved in dauer formation completely blocked Pir, including those altering signaling through the G proteins Goα and Gqα. A model in which sensory neurons transduce the pheromone activity through antagonistic Go and Gq pathways, modulating VA action against neurotransmitter release machinery, is proposed.
A hobo Transgene That Encodes the P-Element Transposase in Drosophila melanogaster: Autoregulation and Cytotype Control of Transposase Activity
Authors: Simmons Michael J , Haley Kevin J , Grimes Craig D , Raymond John D , Niemi Jarad B 
Published: April 2021

Abstract
Drosophila were genetically transformed with a hobo transgene that contains a terminally truncated but otherwise complete P element fused to the promoter from the Drosophila hsp70 gene. Insertions of this H(hsp/CP) transgene on either of the major autosomes produced the P transposase in both the male and female germlines, but not in the soma. Heat-shock treatments significantly increased transposase activity in the female germline; in the male germline, these treatments had little effect. The transposase activity of two insertions of the H(hsp/CP) transgene was not significantly greater than their separate activities, and one insertion of this transgene reduced the transposase activity of P(ry+, Δ2-3)99B, a stable P transgene, in the germline as well as in the soma. These observations suggest that, through alternate splicing, the H(hsp/CP) transgene produces a repressor that feeds back negatively to regulate transposase expression or function in both the somatic and germline tissues. The H(hsp/CP) transgenes are able to induce gonadal dysgenesis when the transposase they encode has P-element targets to attack. However, this ability and the ability to induce P-element excisions are repressed by the P cytotype, a chromosomal/cytoplasmic state that regulates P elements in the germline.