Effect of Rotation Speed Parameter on Mechanical Properties of Similar AISI 1040 Parts Joined by Friction Welding

Friction welding is one of the important joining methods widely used, especially for welding cylindrical parts, in many industries. In this study, friction welding of similar material steel AISI 1040 cylindrical parts having 12 mm diameter is successfully realised at different welding parameters. In order to determine mechanical properties of welds, the tensile strength and microhardness tests as well as microstructural analysis are carried out and discussed. In addition, the comparison between parts welded at different revolutions per minute (rpm) is made in terms of mechanical properties. Experimental results show that the highest tensile strength is nearly 400 MPa, which is obtained at the parts welded through 1500 rpm.Сварка трением является одним из важных способов соединения, который широко используется, в частности, для сварки цилиндрических деталей, во многих отраслях промышленности. В данной работе была проведена сварка трением цилиндрических деталей диаметром 12 мм из стали AISI 1040 при разных параметрах сварки. Для характеризации механических свойств сварных швов определены прочность на растяжение и микротвёрдость, а также выполнен микроструктурный анализ. Кроме того, проведён сравнительный анализ механических свойств деталей, сваренных при различных скоростях вращения. Результаты экспериментов показывают, что максимальная прочность составляет около 400 МПа и достигается при 1500 об/мин.Зварювання тертям є одним з важливих способів з’єднання, який широко використовується, зокрема, для зварювання циліндричних деталів, у багатьох галузях промисловости. В даній роботі було виконано зварювання тертям циліндричних деталів діяметром у 12 мм зі сталі AISI 1040 за різних параметрів зварювання. Для характеризації механічних властивостей зварних швів визначено міцність на розтяг і мікротвердість, а також виконано мікроструктурну аналізу. Крім того, проведено порівняльну аналізу механічних властивостей деталів, зварених за різних швидкостей обертання. Результати експериментів показують, що максимальна міцність становить близько 400 МПа і досягається при 1500 об/хв

The Current Perspectives of Stem Cell Therapy in Orthopedic Surgery

Context: Musculoskeletal injuries may be painful, troublesome, life limiting and also one of the global health problems. There has been considerable amount of interest during the past two decades to stem cells and tissue engineering techniques in orthopedic surgery, especially to manage special and compulsive injuries within the musculoskeletal system. Evidence Acquisition: The aim of this study was to present a literature review regarding the most recent progress in stem cell procedures and current indications in orthopedics clinical care practice. The Medline and PubMed library databases were searched for the articles related with stem cell procedures in the field of orthopedic surgery and additionally the reference list of each article was also included to provide a comprehensive evaluation. Results: Various sources of stem cells have been studied for orthopedics clinical care practice. Stem cell therapy has successfully used for major orthopedic procedures in terms of bone-joint injuries (fractures-bone defects, nonunion, and spinal injuries), osteoarthritis-cartilage defects, ligament-tendon injuries, femoral head osteonecrosis and osteogenesis imperfecta. Stem cells have also used in bone tissue engineering in combining with the scaffolds and provided faster and better healing of tissues. Conclusions: Large amounts of preclinical studies have been made of stem cells and there is an increasing interest to perform these studies within the human population but preclinical studies are insufficient; therefore, much more and efficient studies should be conducted to evaluate the efficacy and safety of stem cells

Discovery of Delta Scuti variables in eclipsing binary systems II.Southern TESS field search

The presence of pulsating stars in eclipsing binary systems (EBs) makes these objects significant since they allow us to investigate the stellar interior structure and evolution. Different types of pulsating stars could be found in EBs such as Delta Scuti variables. Delta Scuti stars in EBs have been known for decades and the increasing number of such systems is important for understanding pulsational structure. Hence, in this study, a research was carried out on the southern TESS field to discover new Delta Scuti stars in EBs. We produced an algorithm to search for detached and semi-detached EBs considering three steps; the orbital period (P$_{orb}$)'s harmonics in the Fourier spectrum, skewness of the light curves, and classification of \textsc{UPSILON} program. If two of these steps classify a system as an EB, the algorithm also identifies it as an EB. The TESS pixel files of targets were also analyzed to see whether the fluxes are contaminated by other systems. No contamination was found. We researched the existence of pulsation through EBs with a visual inspection. To confirm Delta Scuti-type oscillations, the binary variation was removed from the light curve, and residuals were analyzed. Consequently, we identified 42 Delta Scuti candidates in EBs. The P$_{orb}$, $L$, and M$_{V}$ of systems were calculated. Their positions on the H-R diagram and the known orbital-pulsation period relationship were analyzed. We also examined our targets to find if any of them show frequency modulation with the orbital period and discovered one candidate of tidally tilted pulsators.Comment: Published in MNRA

Universal transport in 2D granular superconductors

The transport properties of quench condensed granular superconductors are presented and analyzed. These systems exhibit transitions from insulating to superconducting behavior as a function of inter-grain spacing. Superconductivity is characterized by broad transitions in which the resistance drops exponentially with reducing temperature. The slope of the log R versus T curves turns out to be universaly dependent on the normal state film resistance for all measured granular systems. It does not depend on the material, critical temperature, geometry, or experimental set-up. We discuss possible physical scenarios to explain these findings.Comment: 4 pages, 3 figure

Evaluation of a clinical decision support tool for matching cancer patients to clinical trials using simulation-based research

There is a growing need for alternative methodologies to evaluate digital health solutions in a short timeframe and at relatively low cost. Simulation-based research (SBR) methods have been proposed as an alternative methodology for evaluating digital health solutions; however, few studies have described the applicability of SBR methods to evaluate such solutions. This study used SBR to evaluate the feasibility and user experience of a clinical decision support (CDS) tool used for matching cancer patients to clinical trials. Twenty-five clinicians and research staff were recruited to match 10 synthetic patient cases to clinical trials using both the CDS tool and publicly available online trial databases. Participants were significantly more likely to report having sufficient time (p = 0.020) and to require less mental effort (p = 0.001) to complete trial matching with the CDS tool. Participants required less time for trial matching using the CDS tool, but the difference was not significant (p = 0.093). Most participants reported that they had sufficient guidance to participate in the simulations (96%). This study demonstrates the use of SBR methods is a feasible approach to evaluate digital health solutions and to collect valuable user feedback without the need for implementation in clinical practice. Further research is required to demonstrate the feasibility of using SBR to conduct remote evaluations of digital health solutions

Evaluation of a clinical decision support tool for matching cancer patients to clinical trials using simulation-based research

AbstractSimulation-based research (SBR) methods have been proposed as an alternative methodology for evaluating digital health solutions; however, applicability remains to be established. This study used SBR to evaluate a clinical decision support (CDS) tool used for matching cancer patients to clinical trials. 25 clinicians and research staff were recruited to match 10 synthetic patient cases to clinical trials using both the CDS tool and publicly available online trial databases. Participants were significantly more likely to report having sufficient time (p = 0.020) and to require less mental effort (p = 0.001) to complete trial matching with the CDS tool. Participants required less time for trial matching using the CDS tool, but the difference was not significant (p = 0.093). Most participants reported that they had sufficient guidance to participate in the simulations (96%). This study demonstrates the use of SBR methods is a feasible approach to evaluating digital health solutions.</jats:p