bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystallographic orientation on raft-like structure developed by tensile deformation in Cu-Fe dual phase alloy sheet
Authors: Koga N. , Tomono S. , Umezawa O.
Published: April 2021

The crystallographic orientation of a raft-like structure developed by tensile deformation in Cu-40 mass % Fe dual phase alloy sheet was investigated. The sheet exhibited Cu and Fe layer structure aligned along the rolling direction (RD). The tensile tests were carried out parallel to the RD. The rearrangement of the layer structure was observed in a necked region, where the layers were distorted and aligned along the normal direction (ND). The layered structure perpendicular to the tensile direction is similar to the raft structure developed by creep deformation in a nickel-based super alloy. The bending of layers in the raft-like structure and shear fracture were detected in the cross-section of the samples. The raft-like structure in Cu-Fe dual phase alloy displayed a specific crystal orientation such as <111>Cu//ND, <101>Cu//RD, <101>Fe//ND, and <111>Fe//Rd. The orientations are matched to those rotated 90 degrees around the transverse direction of the layer structure. Therefore, the bending of the layer structure in a necked part and/or local shear deformation may be responsible for the raft-like structure development in Cu-Fe dual phase alloy.
Suppression of serration of Al-Mg sheet by periodic indentation
Authors: Utsunomiya H , Ochi N , Koshi S , Natori K , Matsumoto R
Published: April 2021

Al-Mg alloy sheets often exhibit surface defects, e.g., stretcher strain, after sheet metal forming. The surface defects are formed by nonuniform deformation due to the dynamic strain aging where serrations appear on stress-strain curves in tensile test. In order to suppress the nonuniform deformation, the authors propose periodic micro indentation on sheet surface in this study. Four Al-Mg alloy sheets were subjected to the tensile test after the indentation. Strain gauges on specimen surface were used to investigate the evolution of local strain. It is concluded that the periodic indentation can suppress nonuniform deformation.
Recrystallization behaviour of IF steel at the interface of Al junction
Authors: Okuda K , Han K , Kainuma R
Published: April 2021

The recrystallization behavior of an IF steel was investigated at the interface with aluminum junction, using cold-rolled IF steel sheets with high recrystallization temperature. In the region surrounded by the tongue-like η phase, recrystallization of the steel was fast at first glance, and the equiaxed structure was formed, but actually, it had a subgrain structure. The η phase grew preferentially to the c axis, and the growth of the η-Fe2Al5 phase distorted the surrounding iron due to the difference in the molar volume; compressive deformation was expected in the a-axis and b-axis directions, and tensile deformation was expected in the c-axis. The growth of η phase obviously changed the recrystallization behavior of the IF steel. The development of γ-fiber crystalline texture (<111>/ND), which was a typical recrystallization texture of IF steel, was not observed in the region surrounded by η phase.
Growth of Grains in the Third Orientation in an Inhomogeneous Matrix Consisting of Two Orientation Groups - A Modified Potts–Monte Carlo Simulation
Authors: Ito Kunio
Published: April 2021

The growth of a C-grain embedded in the matrix of A-and B-grains has been simulated. A, B, and C denote orientation groups. Boundaries were defined as “specified” if they consisted of A and C grains, else they were defined as “unspecified”. The edges of an embedded grain were named according to component grains as CAA, CAB, and CBB triple lines. The inhomogeneity of the matrix structure was presented as the ratio between their numbers. When the mobility of specified boundary is higher than that of unspecified boundary, the volume fraction of the C-grain increases with grain coarsening, which is affected by the ratio between triple lines. The results suggest that the development of the grain growth texture is affected by the orientation distribution in a specimen and that the influence must be bigger when the mobility of the triple line depends on the combination of relevant grains.
Variant selection during β to α transformation for Ti-6Al-4V alloy produced by Selective Laser Melting printing
Authors: Xiang H. , Kestens L.A.I. , Van Paepegem W.
Published: April 2021

During 3D printing by Selective Laser Melting (SLM) of the alloy Ti-6Al-4V, the phase transformation of BCC to HCP is associated with selection of particular crystallographic variants. In the present paper, the distribution of misorientation angle along grain boundaries was investigated by EBSd. It is revealed that the main misorientation pairs were located in the interval between 56° and 66°, which contains three theoretical misorientation angles, i.e. 60.00°, 60.83° and 63.26°. The observed misorientation axis/angle pairs were represented in the Rodrigues–Frank space with a certain tolerance angle, which illustrated clearly the distribution of the observed misorientations around the 5 theoretical values. The main peak of the misorientation pairs was observed for

[

10

5

5

3

]

/

63.26

°

with 43.8% frequency, followed by

1

2

0
]
/

60

°

with 21.8% population, whereas a distribution in the absence of variant selection would have produced values of 18.2% and 36.4%, respectively.
Cyclic ring fiber textures in single tungsten fiber-reinforced tungsten composites
Authors: Ciucani U M , Haus L , Gietl H , Riesch J , Pantleon W
Published: April 2021

Tungsten fiber-reinforced tungsten composites are considered as plasma-facing material in future fusion reactors. Such composites are obtained by chemical vapor deposition of tungsten on potassium-doped, drawn tungsten wires. In model composites containing single fibers, particular texture types develop due to the cylindrical geometry of the deposition process. The vapor-deposited tungsten layers form a cyclic <100> ring fiber texture with one of the <100> directions pointing radially along the growth direction. The procedure for revealing this non-standard texture type from orientation data obtained by electron backscatter diffraction is presented. Identification of cyclic textures requires carefully chosen acquisition regions as well as a suitable coordinate system for their analysis. It is demonstrated that quite erroneous conclusions about the texture of the layer would be drawn if this is not accounted for properly.
Twin induced Strain Hardening, Grain Fragmentation, and Texture Evolution during Cold Compression of CP-Ti
Authors: Chouhan Devesh Kumar , Biswas Somjeet
Published: April 2021

This work is a systematic investigation of the twin induced strain hardening behavior, grain fragmentation, and texture evolution during titanium’s cold compression. The compression tests were stopped at intermediate strains for quantitative microscopy by electron backscattered diffraction. The microstructural examination indicates the evolution of {1012} extension twins (ET), {1122} contraction twins (CT) and the interaction between them. The strain hardening rate and its derivative plot could be corroborated with the microstructural features and distinguishes regions of slip and twin dominating zones. The texture evolution indicates that dislocation slips were active apart from deformation twins during deformation. Texturally hard ET evolves, broadens, and interacts in texturally soft grains at low and intermediate strains. The ET regions are suitable for the nucleation of texturally soft CT with further strain. During deformation, ET-ET ∼56.8〈1010〉, CT-CT ∼77〈1010〉, ET-CT ∼87〈4221〉 interactions boundaries and CT-ET ∼44.5〈5140〉 double twins develop.
The role of deformation twins in recrystallization texture formation of the FeGa alloy
Authors: Milyutin V A , Gervasyeva I V
Published: April 2021

It has been found that at cold axial deformation of the (Fe83.4Ga16.6)99.9(NbC)0.1 alloy by hydrostatic extrusion, along with the slip processes, deformation twins are formed. The orientations of these formations in the plane perpendicular to the deformation direction coincide with the crystallographic planes {100} or {110}. It is believed that in bcc alloys, the axial deformation texture <110> is stable and undergoes only a small scattering upon recrystallization. Using the EBSD technique in this work, we have shown that the desired <100> / / DD grains can grow into a deformed <110> / / DD matrix upon primary recrystallization. At the same time, recrystallization of as-deformed samples leads to almost complete destruction of the original texture. The <100> orientation probably develops in connection with the presence of nuclei in the form of the least deformed twins, which are not observed in ordinary iron alloys. This feature of Fe-Ga alloys gives principal possibility of creating necessary cube texture and achieve a high magnetostriction value.
Heterogeneity of microstructure, texture and mechanical properties along the building direction of Ti-6Al-4V alloy developed by SLM
Authors: Widomski C , Solas D , Baudin T , Brisset F , Lebel S , Helbert A-L
Published: April 2021

Selective Laser Melting (SLM) is of great interest to the aerospace industry due to its ability for producing components with complex geometries. The laser melting process induces a high cooling rate (105-107 K/s) and a germination by epitaxy which leads to a columnar microstructure. In the case of Ti-6Al-4V the rate of cooling from the β domain generates a martensitic α’ structure made up of fine needles. The present work describes the microstructural, textural and mechanical heterogeneities along the building direction of Ti-6Al-4V samples produced by SLM with two strategies that have different melt pool size. Characterizations show that both strategies lead to a martensitic microstructure but only the SLM with the greater melting area allows to get homogeneous hardness, texture and β grain size (reconstructed by ARPGE) along building direction.
Effect of post-rolling cooling on the hot-rolled microstructure and texture of a new medium-carbon steel
Authors: Javaheri V , Sadeghpour S , Kaijalainen A , Kamali M R , Kömi J
Published: April 2021

Thermomechanical processing consisted of hot-rolling in the austenitic region with deformation both above and below the non-recrystallization temperature. Immediately after rolling, specimens were directly quenched in water to three different temperatures of 560 °C, 420 °C and room temperature. The first two samples, which were quenched to 560° C and 420°C, immediately cooled slowly in the furnace. The microstructure of samples quenched to 560 °C mostly comprised of upper bainite whereas the samples quenched to 420 °C mainly consisted of lath-type bainite. The microstructure of sample direct-quenched to room temperature was mainly martensite. The transformation texture of all samples at the midthickness position showed the same general texture, consisted of mainly ᵅ and ᵞ fibers components with high intensities close to the transformed copper {112}<110>ᵅ, transformed brass {111}<112>ᵅ and rotated cube {001}<110>ᵅ components. However, the direct-quenched sample produced slightly more intense texture compared to the bainitic samples. The local texture of samples near the rolled surface owing to sever deformation showed the shear features consisting of major components of {112}<111>ᵅ, {110}<112>ᵅ and {110}<111>ᵅ.
Secondary Recrystallization of Grains with Cube Orientation for Pure Iron Tape
Authors: Okai D , Yamamoto A , Doi T , Adachi H
Published: April 2021

The formation mechanism of secondary recrystallized grains with cube orientation has been investigated for a pure iron tape prepared by a three-stage cold-rolling method. The crystal orientation before the final cold-rolling affected the appearance of secondary recrystallized grains with cube orientation. The {0 ī 2}<1 0 0> orientation before the final cold-rolling led to the formation of secondary recrystallized grains with cube orientation on the tape surface.
Evolution of recrystallization texture for Cu-30% Zn alloy sheets with high Young’s modulus in the transverse direction
Authors: Inoue Hirofumi , Ituchi Fumito , Cho Tetsuo
Published: April 2021

Miniaturization of electric connecters with higher stability in the coupling force is demanded as components of electric vehicles. Copper alloys are attractive materials from the perspective of electric conductivity. It is considered that Brass orientations {110}<112> has high Young’s modulus along the transverse direction (TD) since the Young’s moduli of copper single crystals show a maximum value at the <111> direction. The authors could successfully develop the near-Brass orientation in TD of the annealed sheets by performing additional warm rolling at a low reduction in thickness for cold rolled Cu-30% Zn alloy (brass) sheets with material cost lower than pure copper. The near-Brass recrystallization texture with a main component {110}<223> showed maximum orientation density after annealing at 723 K when warm rolling was performed at 623 K. In addition, we discussed the mechanism of the recrystallization texture evolution for Cu-30% Zn alloy sheets, which were subjected to the combined rolling consisting of cold and warm rolling using a conventional rolling mill and subsequently annealed at 723 K, in view of annealing twinning in the early stage of recrystallization.
Regularities of Crystallographic Texture Formation in Products Obtained by Selective Laser Powder Melting
Authors: Isaenkova Margarita , Perlovich Yuriy , Rubanov Anatoliy , Fesenko Vladimir , Yudin Artyom
Published: April 2021

As examples of austenitic steel 316L, nickel alloy (Inconel 625) and titanium alloy VT1-0, the regularities of the development of crystallographic texture in monolithic samples and lattice structures obtained by selective laser melting (SLM) of powder are considered. Crystallization of all of these alloys is carried out by the formation of crystals with a cubic structure {100} <001> (bcc or fcc). Upon subsequent cooling, the titanium samples additionally undergo a β→α phase transformation while maintaining the Burgers orientation relation. A sharp cubic texture {100}<001> is formed in the middle-height layers of a monolithic product, which determines the anisotropy of the properties of SLM samples. The layer-by-layer change in the crystallographic texture is associated with the growth of columnar crystals of the cubic phase, which are formed due to the thermal effect of the molten region on the underlying layers, which determine the orientation of the crystal during its crystallization. This texture is typical for both the fcc-phase of steel and the bcc-titanium phase. In the case of the formation of lattice structures, columnar crystals with a preferred orientation of <001> along the growth direction are formed in the central part of the ribs and nodes along the diameter of the structural elements. On the basis of the crystallographic texture of the steel lattice structures and the mechanical properties of the monolithic specimens, the strain curves of the lattices under their compression were calculated.
Microstructural anisotropy in Electron Beam Melted 316L stainless steels
Authors: Kumar Deepak , Shankar Gyan , Suwas Satyam
Published: April 2021

In recent years electron beam melting has been explored to establish its suitability for product manufacturing as this additive manufacturing route offers advantages which are not achieved in other similar processes. This paper focusses on the prime issues associated with 316L manufactured using electron beam melting. Location dependent microstructure and strain accumulation is found to be completely different at central and peripheral regions in a particular layer. Coarser grains as well as lesser amount of strain value is observed at central region when compared to periphery. Crystallographic texture at centre is seen as intensified <100> parallel to build direction whereas it is weak and relatively scattered (<100> and <110> both) for periphery. BD parallel plane gives a glimpse of available energy as well as repeated thermal cycling as long elongated grains were observed and lowest strained region, depicting the high anisotropic structure altogether.
Research of the occurrence and development of metal defects in sulfide stress cracking inducing environment
Authors: Gabelchenko N I , Kidalov N A , Belov A A , Grigoreva N V , Grebnev Yu V , Zhiltsov N P
Published: April 2021

Comparative studies of the metal of equipment after long-term operation in high hydrogen sulfide environment are carried out. To compare their resistance to sulfide stress cracking, the samples were hydrogenated under a stress of 0.6-0.9 of yield stress in a hydrogen sulfide environment. Characteristic of surface defects (blisters and bubbles) were identified, their size and time of occurrence were determined. To study the further development of the process, the samples were subjected to intense hydrogenation for 6 hours at maximum tensile stresses of 0.95 of the yield stress. Then they were cut across for conducting a metallographic study in order to identify the initiation and development of cracks in the metal. It is shown that steel containing cerium, which promoted the formation of relatively small globular sulfides, has the highest resistance to sulfide stress cracking. Such inclusions, in contrast to sulfide stringers of the FeS and MnS type, were not sources of crack initiation. Another source of crack initiation was the boundaries of pearlite and ferrite grains contaminated with microimpurities.
Investigation of the influence of softening modifiers on the knockout of investment castings
Authors: Kidalov N A , Zhiltsov N P , Gabelchenko N I , Belov A A , Grigoreva N V , Zharkova V F
Published: April 2021

The paper considers the problem of laboriousness of cleaning and knocking out investment casting castings from ceramic molds material. The influence of softening modifiers on the structure and residual strength of ceramic samples was analyzed. A magnesium sulfide and copper chloride were selected for the study because of their temperature of destruction, which is in the range of the calcination temperature of the ceramic shells and the temperature of pouring the mold with liquid metal. For comparative studies of particle size distribution after exposure to shock loading the samples were formed from ceramic suspension with introduction of 1.5 and 3 wt.% of softening modifiers. Fractures of ceramics were examined using a two-beam electron scanning microscope “Versa 3D”. It was shown that the use of copper chloride as a softening modifier in the composition of ceramics is facilitate the process of knockout the mold of investment casting.
Strength analysis of composite plates with auxetic honeycomb at static bending by the finite element method
Authors: Mazaev A V
Published: April 2021

In this paper, three-layer composite plates with continuous outer layers and an auxetic honeycomb interlayer of the chiral type based on rotating circles with tangentially attached rods are modeled. The physical and mechanical properties of the D16 aluminum alloy were chosen as the material properties of the layers of the composite plates. In the course of modeling, the discretization and volume of honeycomb structures in composites were varied at a constant thickness of the layers. Under the conditions of static bending of composite plates, load values were determined, at which maximum stresses in composites were equated to the conditional yield strength. The problem was solved using the finite element method in the framework of the theory of elasticity. The aim of this work is to study the influence of the discretization parameter and volume of the auxetic honeycomb interlayer on the magnitudes of load at yield strength stresses for the proposed composite plates.
Modelling and experimental validation of thermoset resin curing during pultrusion
Authors: Vedernikov A N , Safonov A A , Akhatov I S
Published: April 2021

Mathematical modelling of the pultrusion manufacturing process involves many parameters of the resin mixture. In this article thermo-chemical behavior of resin used for pultrusion of glass fiber/epoxy-vinyl L-shaped profiles was characterized. Profiles were manufactured at pulling speeds of 200, 400, and 600 mm·min-1. Dependency of resin specific heat from temperature was determined by differential scanning calorimetry (DSC); the influence of temperature on resin’s thermal conductivity was found; parameters of resin cure kinetics were described. Subsequently, the gained parameters were used for numerical simulation of the pultrusion thermo-chemical problem in ABAQUS software. The temperature and cure degree evolutions obtained from the experiments run at different pulling speeds, and those from the numerical model were shown to be correlated.
The analysis of technologies and modeling for forming parts in isothermal conditions
Authors: Yakovlev Y I , Rakov D L , Sukhorukov R Y
Published: April 2021

One of the most promising ways to parts making is isothermal in a state of superplasticity. Mathematical modeling is an effective way to determine the necessary energy-force parameters of the process. Examples include the method of analysis and selection of technological processes of parts production in isothermal conditions. The technological processes and simulation of deformation-thermal treatment has been carried out. The simulation ensured the formation of the ultra-fine-grain structure in the blanks under the super-plastic roll-out of the shaft from the alloy EhK79. The modeling shows the effect of the microstructure of alloys on the physical-mechanical and operational properties of parts. Model used to predict microstructure evolution is the Johnson-Mehl-Avrami-Kolmogorov model.
Fracture toughness experimental investigations of metal structures from low-alloyed steel
Authors: Chelnokov A V , Erofeev M N
Published: April 2021

Presented are the results of experimental fracture toughness investigations of metal structures from low-alloyed steel (<0.12% C, 0.6-0.9% Cr, 0.8-1.1% Si, 0.5-0.8% Ni, 0.4-0.6% Cu and others), the influence of structural, technological and operational factors taken into account. The results of the investigations can be used to form a fracture toughness data bank of metal structures for mechanical engineering, to conduct of metal structure defectation, to assess of the brittle fracture risk due to the presence of crack defects, to improve the quality control system at the production stage and to solve other problems of ensuring the safety of machinery and equipment.
Research of the strength of structural elements (wing console) for aviation purposes obtained using 3d printing
Authors: Latypov A D , Moskvitin G V , Naumov O V , Pugachev M S
Published: April 2021

3D printing technology allows you to obtain parts with a number of characteristics that have great importance for a number of areas, in particular small aircraft. The article presents a statistical and modal analysis of the naca0012 configuration wing console made of ABS and PLA plastics. These calculations allow us to draw conclusions about the possibility of using printing technology in the development and design of aircraft.
Influence of running-in in dry and wet conditions on the interfacial adhesion of tire tread rubber
Authors: Morozov A V , Makhovskaya Yu Yu , Kravchuk K S
Published: April 2021

To study the running-in effects on the adhesion properties of tire tread compounds, an approach is proposed based on theoretical analysis of experimental load-distance curves. The approach uses the Maugis model of adhesion in an axisymmetric elastic contact. Classical AFM tests with a ball of 450 nm glued to the probe are performed for two different surfaces of the tire tread rubber after running-in in dry and wet friction regimes and for the original rubber surface. It is shown that running-in in wet conditions decreases the surface energy of rubber. Also, running-in in both wet and dry conditions leads to softening of a surface layer of rubber.
Solid lubricating coatings tribological test rig development
Authors: Prozhega M V , Reschikov E O
Published: April 2021

Solid lubricant coatings are commonly used under difficult operating conditions. Compositions containing graphite and molybdenum disulphide are the most used worldwide. Friction and wear tests are carried out to evaluate solid lubricant quality. Tribological properties are characterised by friction coefficient. The following paper presents the design of a ball-on-disc scheme testing rig. The normal load is applied by weights and remains constant during the entire testing time. The sliding speed is controlled by computer and changes smoothly. A strain gauge is installed to friction force determination. The sensor provides direct measurement of the bending strain and also the torque. The latter to be reduced for higher accuracy. To evaluate the design stiffness and contact point displacement the finite element analysis was done. The test rig is developed in accordance with ASTM G99.
Influence of a thin interlayer and a distribution of microdefects on guided wave dispersion properties in an elastic laminate plate
Authors: Eremin A A , Golub M V , Doroshenko O V , u Gurinovich S Y
Published: April 2021

Adequate mathematical and computational models for damaged interfaces and thin interlayers between two solids are necessary for the non-destructive ultrasonic evaluation of the reliability and safety of bonded structures in service. However, the complexity of real interfaces does not allow to describe their mechanical behaviour precisely. In this paper, the problem of elastic guided wave propagation in a multi-layered structure with thin polymeric plies with possible weakened adhesion is treated uniformly employing effective boundary conditions at sublayer interfaces. While for the pristine structure continuity of the displacements and stresses at the interfaces is assumed, for the damaged interfaces, an approach relying on springlike boundary conditions is used. The effect of the internal layer and damaged interfaces b etween sub-layers on an elastodynamic behaviour of a laminate is analysed. Their influence on the dispersion properties of guided waves propagating in a laminated composite structure is illustrated both theoretically and experimentally.
Wake-induced vibration of two-phase conductors connected by spacers
Authors: Shavnya R A , Danilin A N
Published: April 2021

Considering finite element approach applied to modelling of wind-induced split-phase overhead power line conductor oscillations caused by aerodynamic wake. Model represents an aeroelastic system including twin bundled conductor with spacers. Modified Simpson’s theory is used for conductor wake coupling simulation. Assuming small oscillating conductor deflection from element ends connection line compared to element length, thus the element tension and element tensile strain can be considered as constant values. Strain, as function of transverse displacements, defines as quadratic approximation. Element absolute displacements and twisting angles, together with Ritz’s method coefficients is taken as generalized coordinates, in which conductor move equations are compiled with non-linear elastic, inertial and aerodynamic forces. Appropriate linearized small oscillation equations near the static equilibrium are derived – those can be used for defining system flutter critical wind velocity. An example with split-phase twin bundled conductor, three-sub-span system is presented.
Bearings stiffness parameter estimation by sensitivity method
Authors: Vlasevskiy V N , Belkin A E , Ivanov I I
Published: April 2021

The sensitivity method is applied for bearings stiffness parameter estimation of an experimental rotor system. For model updating, critical shaft speeds are used. The reliability of the sensitivity method is tested on a simple example. The results show that this method can be successfully applied to adjust the finite element model to the experimental data.
Contact-communicative approach to research and development the smart prosthesis for the transradial amputees
Authors: Kovalev N S , Solovyev A A , Sergeev A M
Published: April 2021

The article is devoted to further researches and developments of the smart prosthesis for transradial amputees. Describes the solutions of thematically related tasks to increase the effectiveness of the amputee’s interaction with the external subject-spatial and social environment. One of the tasks is to study the behavior of experimental resistive pressure sensors protective materials in order to optimize sensor contact. Another task is to the provision with the help of conductive materials of the effect of “digital touch” with the aim of creating the amputee through the agency of the screen-compatible prosthesis conditions for active social communication.
Cognitive ergonomics of DNA-algorithms
Authors: Stepanyan I V
Published: April 2021

To improve the ergonomic qualities of graphical interfaces and optimize the visual perception of large data presented in text form, a method of information processing based on DNA algorithms is proposed. These algorithms were developed by the author in the study of the molecular genetic and structural properties of long nucleotide sequences. The result of processing information presented in text form is an object of discrete geometry, two-dimensional projections of which can serve for visual identification of the internal structure of information, as well as for interpretation as characteristic symbols. At the same time, the considered transformations have the property of visualizing the characteristic cluster structure of information. It is shown that genetic nucleotide sequences, as well as texts in natural language, lend themselves to visual classification, which contributes to an increase in the productivity of mental work when analyzing big data. It is shown that DNA algorithms can reduce the load on the visual analyzer during the initial examination of data presented in text form. This makes it possible to apply this method when operators interact with various information streams and text data of arbitrary nature, as well as to improve the ergonomic qualities of specialized graphical interfaces.
The research of a movement dynamics two-legged robot with spring-loaded weight
Authors: Bordyugov D V , Briskin E S , Sharonov N G
Published: April 2021

The movement of a two-legged robot which moves due to oscillations of a load with a given mass fixed on the robot body with the help of the springs, is considered in this research. By changing parameters, such as mass of the load, stiffness of the springs, size of the robot’s body and the initial speed of movement, the various trajectories of movement are executed. In this article mathematical model and calculation results have been presented.
About the geometrical form of the underwater robot platform with non-parallel system the anchor-rope propulsion
Authors: Briskin E S , Sharonov N G , Kalinin Y V , Samozheev I A
Published: April 2021

The underwater mobile transport robot, which is a platform assembled from the polygonal pontoon modules, is considered. The system are used anchor-rope movers, which ensures high stability and energy efficiency of the entire system due to interaction with the bottom surface. The aim of the study is to select the geometric shape of the module according to such criteria as specific heat losses in the movers, the length of the step and the tension of the ropes. The formulated criteria characterize the energy consumption and the level of dynamic loads in the considered dynamic system, and the achievement of their optimal values contributes to the increase of autonomy. It takes into account not only the exchange rate resistance to movement, but also the influence of the current, which, depending on the direction, can both promote the movement of the platform and counteract it.
Synthesis of algorithm for stabilization of spatial position of manipulator gripper of parallel structure
Authors: Dyashkin-Titov V V , Zhoga V V
Published: April 2021

Method of synthesis of kinematic algorithm of stabilization of spatial position of manipulator gripper of parallel-serial structure relative to given position is described in work. Coordinates and speeds and accelerations of generalized coordinates of manipulator are taken as control parameters. Analytical ratios of the control signals of the drive electric motors are obtained, which ensure the movement of the working body of the manipulator in the vicinity of the designated point. Numerical examples of the implementation of the obtained control laws are given.
The results of the impact theory application in modeling the gear shifting processes in automatic transmissions
Authors: Korendyasev G K , Salamandra K B , Tyves L I
Published: April 2021

The process of gear shifting in vehicles automatic transmissions is considered in the paper as the shock interaction of transmission elements. Two mathematical models are proposed and considered for simulation the gear shifting processes. Computer simulation of the models’ movement during acceleration of a vehicle, as well as modes of low - and high-frequency gear shift cycling (self-oscillations of the output shaft of the gearbox) is carried out. Methods for decreasing the amplitude of the gearbox output shaft oscillations caused by the impact nature of gear shifting are proposed.
Research of the process of creating a vacuum on air-permeable surfaces
Authors: Lapikov M A , Kalinin Y V , Makarov A M , Serdobintsev Y P
Published: April 2021

A research of the process of vacuuming on air-permeable surfaces is carried out. A mathematical model is presented for calculating the parameters of the gas filtration process through porous surfaces during their vacuumation. This model allows you to calculate the parameters of vacuum systems for gripping devices necessary for reliable capture of breathable materials.
Precise positioning of mechanisms based on dynamics
Authors: Orekhov S Y , Masyuk V M , Kuznetsov V S , Dolgolenko S P , Kislov K G
Published: April 2021

The purpose of this work is to study the factors that affect the positioning accuracy and find a way to determine the positioning accuracy of a mechatronic system. The paper investigates a model of a hexapod manipulator with six degrees of freedom. A mathematical model of the manipulator has been built. The study of the dependence of the positioning accuracy on the influence of external forces was carried out. It is concluded that manipulators of a parallel structure are applicable for light loads.
Development of a skid for manual contact welding with the machine movement in the working areas
Authors: Boslovyak P V , Dvoretsky V V
Published: April 2021

There is represented the creation of a skid for manual contact welding. It consists of a metal structure of the skid itself and a movement carriage. Strength and stiffness calculations of the metal structure of the skid and of the carriage were performed. A full-scale sample of the skid assembly result is shown.
Calculation and comparative analysis of bucket of the belt elevator
Authors: Boslovyak P V , Shagimardanov V R
Published: April 2021

The calculations of the bucket of a belt elevator for two working cases are presented - at the moment of scooping up the load by the bucket and at the moment of transporting the load into the vertical direction. A 3D model of the bucket was developed in the SolidWorks software package. The calculations of strength and stiffness of the bucket were performed. A comparative analysis of one size range of a bucket with different thicknesses of its walls is carried out.
The influence of 3D printing layer height on frictional properties of ABS plastic
Authors: Slavkina V E , Shitov A O , Lopatina Yu A
Published: April 2021

This work is devoted to the study of tribotechanical properties of 3D printed samples from ABS plastic. The results of determining the coefficient of friction and mass wear of the samples obtained by 3D-printing with different printing heights during the friction testing on machine II 5018 are presented. It is shown that in order to reduce the coefficient of friction and mass wear of the ABS plastic specimen, it is recommended to produce specimens with a higher print height. 3D printed parts with 0.3 mm layer height have shown the best results because of greater layer adhesion.
Feasibility of patient-reported outcome research in acute geriatric medicine: an approach to the ‘post-hospital syndrome’
Authors: Franke Alexander D
Published: April 2021

Background

A patient’s self-reported health-related quality of life (HRQoL) can be quantified by a patient-reported outcome measure (PROM). A patient’s HRQoL can provide another avenue to understand the ‘post-hospital syndrome’, a period after hospital discharge that a patient remains vulnerable to subsequent re-admission. The purpose of the study was to establish the feasibility of collecting HRQoL of older inpatients treated for acute illnesses on medical ward. Feasibility of the PROM would be qualitatively judged upon completion time, response rate and sensitivity to change in HRQoL over time.

Methods

A prospective observational cohort of consecutively admitted patients to a step-down medical ward over 1 year. The COOP/WONCA chart was the PROM. Patients were interviewed by the author face-to-face within 48 hours of admission and then 2 weeks after discharge by telephone.

Results

From the 300 patients admitted, 182 were excluded. Of the remaining 118, median age was 78 years (interquartile range, IQR, 64–86 years), and 71 (60.2%) were female. Proxies were used for 26 (22%) patients. Ninety-two (78%) completed follow-up. The participants were contacted at a median of 14 days (IQR, 13–16) after discharge. Exploratory analyses found that the COOP/WONCA had test–retest responsiveness, that is detected change in HRQoL over time.

Conclusion

The completion time of 3 minutes, high response rate (78%) and test–retest responsiveness are evidence that collecting PROs from acutely unwell elderly patients using the COOP/WONCA is feasible. PRO research could become fundamental to the understanding of the ‘post-hospital syndrome’.
Clinicopathologic Findings in Patients With Initial Diagnosis of Extranodal Marginal Zone B-Cell Lymphoma of Mucosa-Associated Lymphoid Tissue (MALT) in Colorectal Mucosa
Authors: Soma Lorinda A , Smith Stephen D , Reddy Prathima , Edlefsen Kerstin L , Wu David , Cherian Sindhu , Chen Xueyan , Zhou Yi , Reddi Deepti , Fromm Jonathan R
Published: April 2021

Objectives

To evaluate clinicopathologic features, management, and behavior of colorectal extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT).

Methods

Clinical data, laboratory studies, and radiographic records were reviewed (2005-2018), and fluorescence in situ hybridization studies were performed.

Results

Eleven patients were identified, six of whom were discovered as an incidental finding on endoscopy. Morphologic and immunophenotypic features were similar to MALT lymphomas at other sites except that lymphoepithelial lesions were uncommon. Three of nine patients were positive for BIRC3/MALT1 fusions, two of whom had identical B-cell clones identified in subsequent gastric biopsy specimens. Eight of 10 patients had no clinically evaluable disease after observation (±antibiotics; n = 4) or radiation/chemotherapy (n = 4).

Conclusions

Patients with incidental and localized colonic MALT lymphoma demonstrated an excellent prognosis with conservative management, although longer follow-up and data based on consistent staging and surveillance methods (including gastric evaluation) are necessary for informed management.
How I Diagnose Angioimmunoblastic T-Cell Lymphoma
Authors: Xie Yi , Jaffe Elaine S
Published: April 2021

Objectives

Angioimmunoblastic T-cell lymphoma (AITL) is a subtype of peripheral T-cell lymphoma derived from T-follicular helper cells. For pathologists, diagnosing AITL may be challenging due to its wide clinical and histopathologic spectrum, which can mimic a variety of reactive and neoplastic processes.

Methods

We summarize and discuss the clinicopathologic features of AITL, emphasizing diagnostic tools available to the practicing pathologist. Common diagnostic dilemmas are discussed.

Results

AITL exhibits various histologic patterns and is often associated with a prominent microenvironment that can obscure the neoplastic cells. Atypical B-cell proliferations, which can take a number of forms, are common in AITL, and clonal B-cell expansion can be seen. The atypical B cells can closely resemble Hodgkin/Reed-Sternberg cells, leading to misdiagnosis as classic Hodgkin lymphoma. Molecular studies have revealed recurrent genetic alterations, which can aid in differential diagnosis, particularly in problematic cases.

Conclusions

Given the complex diagnostic challenges in AITL, an integrated approach, incorporating clinical, morphologic, immunophenotypic, and molecular findings, is helpful to reach an accurate diagnosis.
Body Mass Index and Mortality Among Adults With Incident Myocardial Infarction
Authors: Al-Shaar Laila , Li Yanping , Rimm Eric B , Manson JoAnn E , Rosner Bernard , Hu Frank B , Stampfer Meir J , Willett Walter C
Published: April 2021

The relationship between body mass index (BMI; weight (kg)/height (m)2) and mortality among survivors of myocardial infarction (MI) remains controversial. We examined the relationships of BMI before and after MI and change in weight with all-cause mortality among participants in the Nurses’ Health Study (1980–2016) and Health Professionals Follow-up Study (1988–2016) cohorts. During a follow-up period of up to 36 years, we documented 4,856 participants with incident nonfatal MI, among whom 2,407 died during follow-up. For pre-MI and post-MI BMI, overweight was not associated with lower mortality. Obesity (BMI ≥30) was associated with higher risk of mortality. Compared with participants with post-MI BMI of 22.5–24.9, hazard ratios were 1.16 (95% confidence interval (CI): 1.01, 1.34) for BMI 30.0–34.9 and 1.52 (95% CI: 1.27, 1.83) for BMI ≥35.0 (P for trend < 0.001). Compared with stable weight from before MI to after MI, a reduction of more than 4 BMI units was associated with increased mortality (hazard ratio = 1.53, 95%: CI: 1.28, 1.83). This increase was seen only among participants who lost weight without improving their physical activity or diet. Our findings showed no survival benefit of excess adiposity in relation to risk of mortality. Weight loss from before to after MI without lifestyle improvement may reflect reverse causation and disease severity.
Clinical impact of pharmacist-led antibiotic stewardship programs in outpatient settings in the United States: A scoping review
Authors: St. Louis James , Okere Arinze Nkemdirim
Published: April 2021

Purpose

To provide an overview of the impact of pharmacist interventions on antibiotic prescribing and the resultant clinical outcomes in an outpatient antibiotic stewardship program (ASP) in the United States.

Methods

Reports on studies of pharmacist-led ASP interventions implemented in US outpatient settings published from January 2000 to November 2020 and indexed in PubMed or Google Scholar were included. Additionally, studies documented at the ClinicalTrials.gov website were evaluated. Study selection was based on predetermined inclusion criteria; only randomized controlled trials, observational studies, nonrandomized controlled trials, and case-control studies conducted in outpatient settings in the United States were included. The primary outcome was the observed differences in antibiotic prescribing or clinical benefits between pharmacist-led ASP interventions and usual care.

Results

Of the 196 studies retrieved for full-text review, a cumulative total of 15 studies were included for final evaluation. Upon analysis, we observed that there was no consistent methodology in the implementation of ASPs and, in most cases, the outcome of interest varied. Nonetheless, there was a trend toward improvement in antibiotic prescribing with pharmacist interventions in ASPs compared with that under usual care (P < 0.05). However, the results of these studies are not easily generalizable.

Conclusion

Our findings suggest a need for a consistent approach for the practical application of outpatient pharmacist-led ASPs. Managed care organizations could play a significant role in ensuring the successful implementation of pharmacist-led ASPs in outpatient settings.
Molecular characterization and enzyme inhibition studies of NADP+- farnesol dehydrogenase from diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)
Authors: Zifruddin Anis-Nadyra , Mohamad-Khalid Khairunnisa-Atiqah , Suhaimi Saidi-Adha , Mohamed-Hussein Zeti-Azura , Hassan Maizom
Published: April 2021

Juvenile hormone III (JH III) plays an important role in insect reproduction, development, and behavior. The second branch of JH III production includes oxidation of farnesol to farnesal by farnesol dehydrogenase. This study reported the identification and characterization of Plutella xylostella farnesol dehydrogenase (PxFoLDH). Our results showed that PxFoLDH belongs to the short-chain dehydrogenase/reductase superfamily, consisting of a single domain with a structurally conserved Rossman fold, an NAD(P) (H)-binding region and a structurally diverse C-terminal region. The purified enzyme displayed maximum activity at 55$\ $°C with pH 9.5 and was stable in the temperature below 70$\ ^\circ $C. PxFoLDH was determined to be a monomer with a relative molecular weight of 27 kDa and highly specific for trans, trans-farnesol, and NADP+. Among analog inhibitors tested, farnesyl acetate was the most effective inhibitor with the lowest Ki value of 0.02 µm. Our findings showed this purified enzyme may represent as NADP+-farnesol dehydrogenase.
Barricyclin D1—a dimeric ellagitannin with a macrocyclic structure—and accompanying tannins from Barringtonia racemosa
Authors: Yoshikawa Shinji , Chen Lih-Geeng , Yoshimura Morio , Amakura Yoshiaki , Hatano Tsutomu , Taniguchi Shoko
Published: April 2021

Our examination of high molecular weight polyphenolic constituents in the leaves of Barringtonia racemosa of the family Lecythidaceae uncovered 5 previously undescribed ellagitannins. One, barringtin M1 (1), among them was a hydrolysable tannin monomer, while remaining 4, barringtins D1 (2), D2 (3), D3 (4), and barricyclin D1 (5), were all dimers. Barricyclin D1 had a first macrocyclic structure formed from casuarictin (6) and tellimagrandin I (7), and the other ellagitannins had structures related to 5. Two additional known phenolics, valoneic acid dilactone (8) and schimawalin A (9), were also isolated from the leaves. These results suggested that the leaves of B. racemosa are a natural resource rich in hydrolysable tannin oligomers.