A bearing is an important component in contemporary machinery and equipment, whose main function is to support the mechanical rotator, reduce the friction coefficient during its movement, and guarantee the turning accuracy. However, assembly of a nanoscale bearing and sleeve is a challenging process for micro-nano mechanical manufacturers. Hence, we show the cold-welding mechanism of a copper nanobearing-nanosleeve via molecular dynamic simulations. We demonstrate that it is feasible to assemble a bearing and sleeve at the nanoscale to form a stable mechanism. The effect of temperature in the range of 150 to 750 K is investigated. As the temperature rises, the mechanical strength and the weld stress of the welded structures markedly decrease, accompanied by the observation of increasing disorder magnitude. This comparison study is believed to facilitate future mechanical processing and structural nano-assembly of metallic elements for better mechanical performance.
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http://dx.doi.org/10.3390/nano8100785 | DOI Listing |
Surg Obes Relat Dis
December 2024
Department of Surgery, Rush University Medical Center, Chicago, Illinois. Electronic address:
Background: Metabolic bariatric surgery is the most effective therapy for severe obesity, which affects the health of millions, most of whom are women of child-bearing age. Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) are the most common bariatric procedures and are associated with durable weight loss and comorbidity resolution. Although obstetric outcomes broadly improve, the safety profile comparing the impact of RYGB and SG on obstetric outcomes is underexplored.
View Article and Find Full Text PDFJBJS Essent Surg Tech
December 2024
Department of Orthopaedics and Rehabilitation, Yale School of Medicine, New Haven, Connecticut.
Background: For complete disruption of the posterolateral corner (PLC) structures, operative treatment is most commonly advocated, as nonoperative treatment has higher rates of persistent lateral laxity and posttraumatic arthritis. Some studies have shown that acute direct repair results in revision rates upwards of 37% to 40% compared with 6% to 9% for initial reconstruction. In a recent study assessing the outcomes of acute repair of PLC avulsion injuries with 2 to 7 years of follow-up, patients with adequate tissue were shown to have a much lower failure rate than previously documented.
View Article and Find Full Text PDFSci Rep
October 2024
School of Civil Engineering, Henan University of Technology, Zhengzhou, 450001, China.
This paper discusses the seismic performance of five reduced-scale shear walls, including one cast-in-place (CIP) concrete shear wall, two precast concrete (PC) shear walls with overlapping U-bar loop connections, and two PC shear walls with modified form-overlapping U-bar loop connections combined with extruded sleeve connections. A quasi-static test was conducted to evaluate the reliability of the overlapping U-bar loop connections and the modified form by comparing the corresponding mechanical parameters of PC specimens with those of the CIP specimen. Moreover, the differences in seismic performance between the CIP specimen and PC specimens with different connection methods were also analyzed in terms of damage process, hysteretic loops and skeleton curves, load carrying capacity, ductility, equivalent stiffness, and energy dissipation.
View Article and Find Full Text PDFMaterials (Basel)
August 2024
China Nonferrous Metals (Guilin) Geology and Mining Co., Ltd., Guilin 541004, China.
The reliable anchorage of carbon fiber-reinforced polymer (CFRP) tendons is a critical issue influencing the stable bearing capacity of bridge cables. This study introduces a novel CFRP single-strand extrusion anchoring structure, where the strand is compressed at its end. By integrating this with internal cone filler wrapping, we create a CFRP multi-strand cable composite anchoring system.
View Article and Find Full Text PDFMaterials (Basel)
July 2024
Henan Provincial Communications Planning & Design Institute Co., Ltd., Zhengzhou 451450, China.
In order to reveal the mechanism of sleeved stud connectors, 15 push-out specimens were designed, and static loading tests were conducted to evaluate the mechanical performance. The shear performance differences between the novel sleeved studs and conventional welded studs were compared. Referring to the experimental results, an Abaqus nonlinear finite element model was established to study the shear mechanism of sleeved stud connectors.
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