bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on the Reliability of the Operating Performance of the Relief Valve of Nuclear Power Plant under Seismic Conditions
Authors: Huazheng Shang , Xinhai Yu
Published: April 2021

Nowadays, environmental and energy problems are becoming increasingly prominent. Nuclear power plants are an important means to solve these two problems. Therefore, research on the reliability of nuclear power plants is closely related to environmental and energy issues. The reliability research of nuclear safety valves has always been the top priority in the reliability research of nuclear power plants, so the reliability of the operation performance of such relief valves must be considered under seismic conditions. This article borrows ANSYS to carry out fluid-solid coupling simulation of relief valves, including simulations under seismic conditions and non-seismic conditions, and explores changes during opening and closing under various conditions, including the opening height, pressure and velocity in internal flow field ,inlet pressure ,solid stress and solid strain. Finally, a test comparison shows that the effect of longitudinal seismic load on the return pressure of the relief valve can be ignored.
Boosting dimensional stability and proton conductive of proton exchange membrane by introducing SO3H-UiO-66 coated nanofibers
Authors: Zhu Bensheng , Sui Yang , Wei Peng , Wen Jihong , Cao Hui , Cong Chuanbo , Meng Xiaoyu , Zhou Qiong
Published: April 2021

In this work, we fabricated cross-linked pre-oxidized polyacrylonitrile nanofibers (PPNF) coating SO3H-UiO-66 coated (named SU6@PPNF), which was introduced into sulfonated poly (ether ether ketone) SPEEK to produce membrane with superior proton conductivity, dimensional stability and mechanical properties under hydrated condition. The membrane displays a maximum power density of 172.1 mW cm-2 under 100% RH and 60 °C, which is an increase of 12.2% compared with primary membrane.
Research on New Battery System with Energy-Saving and Environment-Friendly Materials
Authors: Junming Li , Fang Zhang , Xiaochen Yu , Hainan Su , Xin Yu , Jing Pang , Hongxu Xie
Published: April 2021

Applying the lithium iron phosphate battery online monitoring system to the DC power supply system of the substation is an innovative measure for energy saving and environmental protection of power enterprises. Nowadays, the world is advocating the use of energy-saving and environmentally-friendly green resources, which undoubtedly opens up a wider space for the research of lithium iron phosphate batteries. The article focuses on the performance analysis of the lithium iron phosphate battery system, the research significance, the composition of the system and the key technologies used.
The reduction process of petroleum content in marine oil spill in Jiaozhou Bay
Authors: Yang Dongfang , Li Haixia , Lin Dong , Zhang Yuan , Wang Qi
Published: April 2021

According to the survey data about the waters of Jiaozhou Bay in May, September, and October 1993, this paper studies the content of PHC and its horizontal distribution in the surface waters of Jiaozhou Bay. The result shows that the range of PHC content in the waters of Jiaozhou bay is 4.16–51.00μg/L, which conforms to the national first, second and third water quality standards. In terms of PHC content, the water quality of Jiaozhou Bay is slightly polluted by PHC content in May, September and October. In May, the range of PHC content in the water of Jiaozhou Bay is 4.16–51.00μg/L, which is slightly polluted by PHC content. In the center of east waters, the water quality is slightly polluted by PHC content and the range of PHC content in other water fields of Jiaozhou Bay is 4.16–48.40μg/L which indicates that the water quality is not polluted by PHC content. In September, the range of PHC content in the waters of Jiaozhou Bay is 6.17–12.70μg/L, which is not polluted by PHC content. In October, the range of PHC content is 11.40–11.80μg/L, indicating that the waters of Jiaozhou Bay are not polluted by PHC. The content of PHC in the waters of Jiaozhou Bay only has one source, the transportation of marine oil spill, and the PHC content transported is 12.70–51.00μg/L. Therefore, as time changes, the ocean polluted by PHC content resulting from marine oil spill has gradually reduced over the course of the year. The marine oil spill has caused the waters in May to be slightly polluted by the PHC content. By September, the waters are not polluted by the PHC content. And then, in October, the marine oil spill has disappeared.
Hot topics and frontier evolution of research on entrepreneurial intentions——Visual analysis based on the core collection of Web of science database
Authors: Liu Lou , Chen Bingni
Published: April 2021

Since the Chinese slogan “Mass Entrepreneurship, Mass Innovation” was put forward, entrepreneurship has become a hot topic of research in academic circles and even people from all walks of life. Entrepreneurial Intentions is the best indicator to effectively predict entrepreneurial behavior. In order to understand the research status and trends of entrepreneurship intentions, based on the bibliometric method, this paper uses citespace software to visually analyze 1,038 core collections published in the Web of science database platform from January 1, 1997 to December 31, 2020. The results show that in the past 20 years, the research on entrepreneurial intentions has mainly focused on scholars from foreign universities. The distribution of research institutions is relatively concentrated, but the distribution of journals is relatively loose. Antecedent variables have become the focus of research. Future research should focus on outcome variables.
Finite Element Analysis of Oil and Gas Field Development Completion Tool Based on ANSYS
Authors: Liu Yanli , Fu Daqi , Zhang Gaofeng , Yang Yanzheng , Zhang Haijun , Li Haiwei
Published: April 2021

At persent, multi expandable patching can’t be operated below the patched period of casing damage wells, a varible diameter expandable cone has been designed, so expandable tools can be put into wells with small diameter and expanded with large diameter which can achieve the purpose of patching for casing damage wells for many times. The indoor prototype testing showed that the tools had a suitable structure, start-up pressure was 3–5MPa,complete closure pressure was 52MPa,maximum overall diameter increased from 188 mm to 220 mm, with the same size of conventional expandable cone, expandable rate was 17.02%.The research results showed that expandable force increases linearly with the increase of thrust, expandable tools could be put into wells with small diameter and expanded with large diameter with the help of variable diameter expandable cone, it should have a broad application prospect after rudcing the closure pressure.
Advances and prospects in heat pipe: A critical eview
Authors: Chen Li-Ping , Yu Li-Peng , Hao Meng-Chao , Li Yu-Sen , Wang Qi-Wu
Published: April 2021

As an efficient heat transfer element, the heat pipe has excellent thermal conductivity. It has important application value in chemical, building materials, metallurgy, power engineering, bioengineering and other fields. In order to systematically analyze the development trend of heat pipe, the paper takes the literature on heat pipe from 2010 to 2020 included in the Web of Science database as the data source, and analyzes the collected data with information visualization software CiteSpace to draw out the heat pipe technology countries, institutions, research authors distribution network map, showing the technology research power distribution and cooperation in scientific research. The use of software co-occurrence analysis of the hot science and technology of heat pipe technology, at the same time, the key words co-occurrence network diagram and literature citation network are used to analyze the research hotspots, research frontiers and trends of heat pipe technology.
Selection and Evaluation of influencing Parameters for Heat Load Forecasting Model
Authors: Wu Yuli , Li Rui
Published: April 2021

This paper analyses the factors affecting the heating consumption of a heating substation. The input parameters of neural network prediction model are analysed and selected. The average absolute error, average absolute percentage error, and mean square error are used to evaluate the effect of the prediction model. The results show that when the model input parameters are the maximum outdoor temperature, the average outdoor temperature, the average temperature difference between the primary supply and return of domestic hot water, the heating load in the previous three days, the heating load in the previous two days, the heating load in the previous day and when the model input parameters are the maximum outdoor temperature, the minimum outdoor temperature, the average outdoor temperature, the average temperature difference between the primary supply and return of domestic hot water, the heating load of the previous three days, the heating load of the previous two days, the heating load of the previous day, the effects are better.
Research on the Optimal Path of Enterprise Green Technology Innovation
Authors: Li Zhiyu , Lv Pengjuan , Hong Shuai
Published: April 2021

The construction of a green technology innovation system should not only give attention to technological innovation, but also pay attention to the heterogeneity of the enterprise itself. Therefore, from the dual perspectives of environmental regulation and corporate heterogeneity, we analyze the impact of corporate green technology innovation and believe that building a market-oriented green technology innovation system requires improving green development efficiency, promoting green technology R&D and application, and strengthening the combination of policy tools. Thus to support green transformation and development.
Inanspruchnahme der gesundheitlichen Versorgung von Menschen mit geistiger Behinderung, eine Querschnittstudie in 3 Werkstätten
Authors: Wellkamp Randi , de Cruppé Werner , Schwalen Susanne , Geraedts Max
Published: April 2021

Ziel der Studie Menschen mit geistiger Behinderung weisen eine geringere Lebenserwartung und häufigere Komorbidität als die Allgemeinbevölkerung sowie ungedeckte Gesundheitsbedarfe auf. Als ein Grund wird eine unzureichende medizinische Versorgung vermutet, wozu in Deutschland wenige Daten vorliegen. Die Studie widmet sich deshalb der Frage, wie Menschen mit geistiger Behinderung die medizinische Versorgung einschließlich Vorsorge und präventive Angebote in Anspruch nehmen.

Methodik Querschnittstudie in 3 Werkstätten für Menschen mit geistiger Behinderung. Von Angehörigen wurde die Inanspruchnahme der Gesundheitsversorgung per Fragebogen erhoben. Die Auswertung erfolgte deskriptiv und inferenzstatistisch im Vergleich zur Allgemeinbevölkerung sowie innerhalb der Teilnehmenden auf soziodemografische Unterschiede.

Ergebnisse Fast alle 181 Teilnehmer (Teilnahmequote 19,3%) haben einen Hausarzt. Im Vergleich zur Allgemeinbevölkerung nehmen die Teilnehmer die hausärztliche und die Versorgung durch zahlreiche andere Facharztgebiete häufiger in Anspruch. Die Krebsvorsorge für Dickdarm, Brust, Gebärmutterhals und Prostata nehmen sie seltener, für Haut und den Check-up öfter in Anspruch. Bei Zahnarztkontrollen und Maßnahmen der Gesundheitsförderung zeigt sich kein Unterschied. Teilnehmer aus Wohnheimen nehmen die Regelangebote mehr in Anspruch als die bei Angehörigen oder alleine Lebenden. Teilnehmer mit Migrationshintergrund kennen die Versorgungsangebote weniger gut.

Schlussfolgerung Hinweise auf eine generelle gesundheitliche Unterversorgung zeigen die Ergebnisse nicht. Die Teilnahme an der Krebsvorsorge mit aufwändigeren Untersuchungen sollte gefördert werden, insbesondere für die allein oder bei Angehörigen lebenden Menschen mit geistiger Behinderung; Menschen mit Migrationshintergrund und ihre Angehörigen sollten gezielt informiert werden.
Clinical validation of the SIMPLE classification for optical diagnosis of colorectal polyps
Authors: Alaoui Ahmed Amine , Oumedjbeur Kussil , Djinbachian Roupen , Marchand Étienne , Marques Paola N. , Bouin Mickael , Bouchard Simon , von Renteln Daniel
Published: April 2021

Background and study aims A novel endoscopic optical diagnosis classification system (SIMPLE) has recently been developed. This study aimed to evaluate the SIMPLE classification in a clinical cohort.

Patients and methods All diminutive and small colorectal polyps found in a cohort of individuals undergoing screening, diagnostic, or surveillance colonoscopies underwent optical diagnosis using image-enhanced endoscopy (IEE) and the SIMPLE classification. The primary outcome was the agreement of surveillance intervals determined by optical diagnosis compared with pathology-based results for diminutive polyps. Secondary outcomes included the negative predictive value (NPV) for rectosigmoid adenomas, the percentage of pathology exams avoided, and the percentage of immediate surveillance interval recommendations. Analysis of optical diagnosis for polyps ≤ 10 mm was also performed.

Results 399 patients (median age 62.6 years; 55.6 % female) were enrolled. For patients with at least one polyp ≤ 5 mm undergoing optical diagnosis, agreement with pathology-based surveillance intervals was 93.5 % (95 % confidence interval [CI] 91.4–95.6). The NPV for rectosigmoid adenomas was 86.7 % (95 %CI 77.5–93.2). When using optical diagnosis, pathology analysis could be avoided in 61.5 % (95 %CI 56.9–66.2) of diminutive polyps, and post-colonoscopy surveillance intervals could be given immediately to 70.9 % (95 %CI 66.5–75.4) of patients. For patients with at least one ≤ 10 mm polyp, agreement with pathology-based surveillance intervals was 92.7 % (95 %CI 89.7–95.1). NPV for rectosigmoid adenomas ≤ 10 mm was 85.1 % (95 %CI CI 76.3–91.6).

Conclusions IEE with the SIMPLE classification achieved the quality benchmark for the resect and discard strategy; however, the NPV for rectosigmoid polyps requires improvement.
Fertilitätserhalt bei Patienten in der Dermatoonkologie – Eine aktuelle Übersicht
Authors: Günther V. , Alkatout I. , Maass N. , von Otte S.
Published: April 2021

Bei vielen Patienten, die an einem Malignom erkranken, ist die Familienplanung noch nicht abgeschlossen, sodass für den Erhalt des fertilen Potenzials Maßnahmen der Fertilitätsprotektion sinnvoll sind. Durch eine Polychemotherapie, unabhängig ob im neoadjuvanten oder adjuvanten Setting, Molekular- oder Immuntherapien kann es zu einer irreversiblen Schädigung der Follikel bzw. Spermatogenese kommen, was u. U. zu einer permanenten Infertilität führen kann. Abhängig von der verwendeten Therapie und der altersabhängigen Ovarialreserve der Frau muss das gonadotoxische Risiko als niedrig, mittel oder hoch eingeschätzt werden. Möglichkeiten des Fertilitäserhalts sind: a) die Kryokonservierung von fertilisierten oder unfertilisierten Oozyten. Hierbei werden nach ovarieller Hyperstimulation reife Oozyten mittels transvaginaler Follikelaspiration gewonnen und im Anschluss entweder unfertilisiert oder nach erfolgter IVF- oder ICSI-Behandlung kryokonserviert. Bei b) der Kryokonservierung von Ovarialgewebe wird mithilfe eines laparoskopischen Eingriffs etwa 50 % des Ovarkortex eines Ovars reseziert und kryokonserviert. Die Verwendung von c) GnRH-Agonisten als medikamentöse Therapieoption unternimmt den Versuch einer endokrinen Ovarialsuppression, um Oozyten, Granulosa- und Thekazellen vor dem zytotoxischen Einfluss der jeweiligen Therapie zu schützen. Bei männlichen Patienten können Spermien vor Therapiebeginn kryokonserviert werden.
A Concept for the Reduction of Mucosal SARS-CoV-2 Load using Hypochloric Acid Solutions
Authors: Mueller Christian A. , Winter Michael , Renner Bertold
Published: April 2021

During the next few months or years, vaccination against SARS-CoV-2 infection will significantly reduce the morbidity and mortality of COVID-19. However, additional measures are needed to protect those who are still not immunized. This is even more important in view of new viral mutations that result in increased transmission rates. We propose that the use of long-standing medicinal solutions based on hypochloric acid (HOCl) and intended for application on wounds may be effective as a gargling solution or nasal irrigation in blocking transmission of the virus. Here, we propose the use of HOCl-containing solutions for blocking the transmission of SARS-CoV-2 in combination with other prevention measures. This may constitute another important cornerstone in the fight against the COVID-19 pandemic.
Analysis of tunable Bleustein–Gulyaev permittivity sensors
Authors: Elhady Alaa , Basha Mohamed , Abdel-Rahman Eihab M.
Published: April 2021

We present a novel electric permittivity sensor based on Bleustein–Gulyaev (BG) waves. Toward that end, we formulate the nonlinear electromechanical partial differential equations governing a BG wave resonator. We find that the permittivity of the material-under-test changes the sensor natural frequencies, thereby enabling the implementation of a frequency-shift permittivity sensor. We also find that the sensor sensitivity is enhanced by increasing bias voltage to drive the sensor into the nonlinear regime. Bias was found to be limited by electrical breakdown. The sensor was fabricated by depositing aluminum electrodes on a shear-poled lead zirconate titanate piezoelectric substrate. Experimental measurements of the displacement on the sensor surface were in good agreement with the developed model.
Effect of the initial temperature on the shock response of Cu50Zr50 bulk metallic glass by molecular dynamics simulation
Authors: Wen Peng , Demaske Brian , Spearot Douglas E. , Phillpot Simon R. , Tao Gang
Published: April 2021

The effect of initial temperature on the shock response of Cu50Zr50 bulk metallic glass (BMG) is investigated by molecular dynamics simulations using the multiscale shock technique. The shock Hugoniot relationship of Cu50Zr50 BMG shows an obvious temperature dependence. At the Hugoniot elastic limit (HEL), the critical shear stress decreases with increasing initial temperature; this is modeled based on the activation of shear transformation zones. Shock at high temperatures shows a pressure-dependent HEL. The deformation map reveals that there are three deformation regimes under different shock intensities and temperatures: elastic, plastic, and shock-induced melting. The flow stress decreases with increasing initial temperature confirming that high temperatures reduce the shear resistance of the Cu50Zr50 BMG. At high temperatures and pressures, a shock-induced melting regime is identified using a diffusivity-based analysis.
Excessive rumen-protected choline in the daily diet compromises sperm quality of male dairy goats as a result of aberrant DNA methylation modification
Authors: Wu Hao , Pan Xiaorong , Li Rong , Song Wangcheng , Hua Song
Published: April 2021

Context Choline is added to the diet of ruminants to improve animal growth, development and reproduction; however, little information is available regarding effects of dietary choline supplementation, in the form of rumen-protected choline (RPC), on fertility of male ruminants. Excess RPC in the diet might damage ram fertility through abnormal alteration of methylation patterns at the imprinting control region (ICR) of imprinted genes H19/IGF2. Aims The present study evaluated the influence of different levels of RPC supplementation on the sperm quality of male Saanen dairy goats. Methods Different proportions of RPC (0%, 0.5%, 1.0% and 2.0% of daily concentrate feed) were added to the diet of Saanen bucks. Sperm quality parameters, subsequent in vitro embryo development potential, and kidding rates post artificial insemination were examined. In addition, differences in methylation status of the global DNA, and at 20 CpG sites in the ICR of imprinted genes H19/IGF2, were compared. Key results Supplementation of the daily diet with 0.5% RPC significantly improved sperm quality, and increased subsequent embryo development and kidding rates. However, the two higher RPC-supplemented groups showed significantly reduced kidding rate. Moreover, methylation levels of both the ICR of H19/IGF2 and the global DNA increased significantly with increasing supplemental RPC, and the expression of IGF2 was significantly inhibited in sperm samples from the 1.0% and 2.0% RPC groups, whereas H19, which should had been silenced, showed high expression. Conclusions Adding excessive RPC (≥1%) to the daily diet of male goats might disturb the process of spermatogenesis and is associated with abnormal methylation modification caused by aberrant expression of DNMT1, DNMT3a and DNMT3b in sperm. Implications This study determines the safe amount of choline to add to the diet during the breeding of male dairy goats. This provides a reference for improving the breeding efficiency and saving the breeding cost of dairy goats.
Solanum quitoense (naranjilla).
Authors: Rojas-Sandoval Julissa
Published: April 2021

A datasheet on Solanum quitoense covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Dark etching regions under rolling contact fatigue: A review
Authors: Echeverri Restrepo S. , Ooi S. W. , Yan P. , Andric P. , Vegter R. H. , Lai J.
Published: April 2021

Bearing performance depends on the ability of steel to cope with a large number of stress cycles. Long bearing lives are possible because the microstructure of bearing steel has excellent resistance to Rolling Contact Fatigue (RCF). Nevertheless, it is observed that the microstructure suffers changes in the region where the maximum Hertzian contact stress occurs. Here we give an overview of the present knowledge in the area of the formation of dark etching regions (DERs) during RCF. Factors that influence the formation of DERs, various types of characterisation techniques, and the observations made in the literature are discussed. In addition, the applicability of several proposed simulation models of the formation of DERs is discussed.
The effect of sex hormones on skeletal muscle adaptation in females
Authors: Alexander Sarah E. , Pollock Alexander C. , Lamon Séverine
Published: April 2021

Sex steroids, commonly referred to as sex hormones, are integral to the development and maintenance of the human reproductive system. In addition, male (androgens) and female (estrogens and progestogens) sex hormones promote the development of secondary sex characteristics by targeting a range of other tissues, including skeletal muscle. The role of androgens on skeletal muscle mass, function and metabolism has been well described in males, yet female specific studies are scarce in the literature. This narrative review summarises the available evidence around the mechanistic role of androgens, estrogens and progestogens in female skeletal muscle. An analysis of the literature indicates that sex steroids play important roles in the regulation of female skeletal muscle mass and function. The free fractions of testosterone and progesterone in serum were consistently associated with the regulation of muscle mass, while estrogens may be primarily involved in mediating the muscle contractile function in conjunction with other sex hormones. Muscle strength was however not directly associated with any hormone in isolation when at physiological concentrations. Importantly, recent evidence suggests that intramuscular sex hormone concentrations may be more strongly associated with muscle size and function than circulating forms, providing interesting opportunities for future research. By combining cross‐sectional, interventional and mechanical studies, this review aims to provide a broad, multidisciplinary picture of the current knowledge of the effects of sex steroids on skeletal muscle in females, with a focus on the regulation of muscle size and function and an insight into their clinical implications.

Highlights

Free testosterone, but not total testosterone, is associated with lean mass but not strength in pre‐ and post‐menopausal females.

Progesterone and estrogens may regulate muscle mass and strength, respectively, in females.

Intra‐muscular steroids may be more closely associated to muscle mass and strength, compared to systemic fractions.
Mavacamten has a differential impact on force generation in myofibrils from rabbit psoas and human cardiac muscle
Authors: Scellini Beatrice , Piroddi Nicoletta , Dente Marica , Vitale Giulia , Pioner Josè Manuel , Coppini Raffaele , Ferrantini Cecilia , Poggesi Corrado , Tesi Chiara
Published: April 2021

Mavacamten (MYK-461) is a small-molecule allosteric inhibitor of sarcomeric myosins being used in preclinical/clinical trials for hypertrophic cardiomyopathy treatment. A better understanding of its impact on force generation in intact or skinned striated muscle preparations, especially for human cardiac muscle, has been hindered by diffusional barriers. These limitations have been overcome by mechanical experiments using myofibrils subject to perturbations of the contractile environment by sudden solution changes. Here, we characterize the action of mavacamten in human ventricular myofibrils compared with fast skeletal myofibrils from rabbit psoas. Mavacamten had a fast, fully reversible, and dose-dependent negative effect on maximal Ca2+-activated isometric force at 15°C, which can be explained by a sudden decrease in the number of heads functionally available for interaction with actin. It also decreased the kinetics of force development in fast skeletal myofibrils, while it had no effect in human ventricular myofibrils. For both myofibril types, the effects of mavacamten were independent from phosphate in the low-concentration range. Mavacamten did not alter force relaxation of fast skeletal myofibrils, but it significantly accelerated the relaxation of human ventricular myofibrils. Lastly, mavacamten had no effect on resting tension but inhibited the ADP-stimulated force in the absence of Ca2+. Altogether, these effects outline a motor isoform–specific dependence of the inhibitory effect of mavacamten on force generation, which is mediated by a reduction in the availability of strongly actin-binding heads. Mavacamten may thus alter the interplay between thick and thin filament regulation mechanisms of contraction in association with the widely documented drug effect of stabilizing myosin motor heads into autoinhibited states.
Losing the trace to find dynamical Newton or Planck constants
Authors: Jiroušek Pavel , Shimada Keigo , Vikman Alexander , Yamaguchi Masahide
Published: April 2021

We show that promoting the trace part of the Einstein equations to
a trivial identity results in the Newton constant being an integration
constant. Thus, in this formulation the Newton constant is a global
dynamical degree of freedom which is also a subject to quantization
and quantum fluctuations. This is similar to what happens to the cosmological
constant in the unimodular gravity where the trace part of the Einstein
equations is lost in a different way. We introduce a constrained variational
formulation of these modified Einstein equations. Then, drawing on
analogies with the Henneaux-Teitelboim action for unimodular gravity,
we construct different general-covariant actions resulting in these
dynamics. The inverse of dynamical Newton constant is canonically
conjugated to the Ricci scalar integrated over spacetime. Surprisingly,
instead of the dynamical Newton constant one can formulate an equivalent
theory with a dynamical Planck constant. Finally, we show that an
axion-like field can play a role of the gravitational Newton constant
or even of the quantum Planck constant.
Evolutions of Mechanical Properties and Macro Textures of AZ91D sheets by Hot Rolling and Subsequent Annealing
Authors: Kaneko S , Takenouchi S , Lee S M , Utsunomiya H
Published: April 2021

The mechanical properties and textures of 75% hot unidirectionally rolled and cross rolled commercial magnesium die-casting alloy AZ91D sheets were investigated for the different rolling temperatures 623K and 673K, respectively. As for mechanical properties, tensile testing results show total elongations of both as-unidirectional and as-cross-rolled sheets are enhanced by the repetition of rolling passes and inter-pass heating. The planar anisotropy of tensile strengths and elongations of cross-rolled at 673K are the smallest among the rolling conditions employed in the present study. Annealed sheets demonstrate the significant elongation to failure due to the static recrystallisation at 623K. Macro textures of the as-unidirectional-rolled sheets show typical double-peak (0001) basal textures with inclined peaks towards ±15° in RD. Contrastingly, macro textures of the as-cross-rolled sheets show the significant (0001) basal textures having double peaks at ±10° in TD and concentrically broader orientation distribution in RD and TD.
Texture and mechanical properties of Cu alloy by cryogenic high-speed rolling
Authors: Lee S , Muchime R , Matsumoto R , Utsunomiya H
Published: April 2021

Cryogenic high-speed rolling (CHSR), where the sheet cooled in liquid nitrogen is supplied to rolls rotating at 1500 m/min at room temperature, was applied to several Cu alloys. After the CHSR, mechanical strength was improved with texture transition from the ‘copper-type’ to the ‘brass-type’ components. This trend was clearly observed in the case of Cu alloys with intermediate SFE. It is considered that the deformation mode changed from the dislocation slip to deformation twinning and shear banding under high Z parameter conditions of CHSR. It is also found that CHSR can improve the strength of Cu alloys with less decrease in electrical conductivity.
The Origin of the Cube ({001}<100>) Texture in Non-oriented Electrical Steel Sheets
Authors: He Youliang , Mehdi M , Hilinski E J , Kestens L A I , Edrisy A
Published: April 2021

Although cube ({001}<100>) is a preferred final texture in non-oriented electrical steel (NOES) sheets, this texture is rarely produced in commercial NOES products. The major texture of fully processed NOES is usually the unfavorable <111>//ND (normal direction) fibre, which originates from the deformed <111>//ND texture. To reduce/eliminate the <111>//ND texture and promote the cube texture, one method is to change the initial texture before cold rolling. In this research, two electrical steels containing 0.88 wt% and 2.8 wt% Si are cold rolled with the initial textures rotated by 60° around the ND before cold rolling. This rotation leads to the rotated Goss ({110}<110>) texture in the deformed microstructure. Within the shear bands of the rotated Goss grains, crystallites with cube orientation are formed. Regions of these crystallites may have lower stored energy than their neighboring areas. During annealing, these crystallites preferentially nucleate and grow, and form a strong cube texture in the final steel sheets.
Effects of Fe, Si, and Cu on Recrystallization Behavior in High Purity Aluminum Foil
Authors: Yamanoi T
Published: April 2021

The correlation between the recrystallization behavior of high purity aluminum foil, which is used as the electrode material of electrolytic capacitors, and the influence of Fe, Si, and Cu contents on the formation of recrystallization texture was systematically investigated. The following results were obtained: (1) Room-temperature recrystallization, which occurs during cold rolling of the highest-purity material, was suppressed by adding approximately 10 mass ppm of Fe, Si, and Cu. The effect was strongest for Cu, followed by that for Si and Fe. (2) The main component of texture after the final heat treatment changed in the order {001}<100>→ {011 }<411>→> {126}<411>→ {123}<412> as the purity of the aluminum foil decreased. In particular, {126}<411> was an characteristic orientation for extremely coarse grains and was considered to have originated from the rolling texture (β-fiber). This coarse grain growth was considered to be related to the decrease in the growth rate of the recrystallized grains depending on the purity of the matrix.
Strong rotated cube textures in thin cold-rolled potassium-doped tungsten sheets during annealing up to 1300 °C
Authors: Tarras Madsen D , Ciucani U M , Hoffmann A , Pantleon W
Published: April 2021

Due to the high operation temperatures, microstructural changes will occur in tungsten when used as plasma-facing material in future fusion reactors. In drawn tungsten wires, potassium doping has proven to prevent such undesired changes effectively. This strategy has been adapted to thin cold-rolled tungsten sheets containing 80 ppm potassium. Their texture evolution during annealing is investigated using electron backscatter diffraction. In the as-rolled condition, a strong cube texture is present with a volume fraction of 67.0 % deviating maximal 15° from the rotated cube orientation. This texture intensifies strongly during isochronal annealing for 2 h at temperatures between 1000 °C and 1300 °C; the higher the temperature, the higher the rotated cube fraction. The volume fraction of 94.8 % obtained after 2 h at 1300 °C does not change significantly during further annealing. These are remarkably strong textures for a body-centered cubic metal compared e.g. to commonly reported high volume fractions of 30 % for Goss orientations in silicon steels. Reliable quantification of such strong texture components requires analysis of orientations individually.
Variant Selection in Phase Transformation and its Influence on Texture and Martensite Starting Temperature in Steel
Authors: Tomida T , Sato S
Published: April 2021

A mechanism is proposed that can predict the textures as well as the influence of austenite grain size on martensite starting temperature in steels. The anisotropic elastic energy by shape change of martensite changes depending upon variants in neighbour austenite grains, whereas it does not in immediate parent grains in which martensite grows. A mechanism based on this behaviour of elastic energy can explain not only the texture formation of martensite but also the well-known austenite grain size dependence of Ms, particularly the abrupt drop of about 30K in the grain size range below 20 μm.
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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.