Present studies show that steel fibres can improve the bond of steel bar in steel fibre reinforced concrete (SFRC) with a correlation to the fibre factor and the fibre distribution uniformity. As a foundation of high-flowability SFRC working together with 400 MPa grade hot-rolled ribbed (HRB400) steel bar in reinforced structures, the bond between them was evaluated through a series of pull-out testing on 48 specimens with a central arranged steel bar. The bond behaviours of steel bar were estimated with a constant bond length of 5d (d is the diameter of steel bar) embedded in high-flowability SFRC, the main research parameters included the ingot mill steel fibres with a fibre volume fraction varied from 0.
View Article and Find Full Text PDFThe development of structures that can adapt spontaneously to achieve desired functions in complex environments is crucial for new unmanned countermeasures, such as prey capture or net-recovery. Conventional structural optimization methods based on a singular net-like configuration may lead to functional limitations and fail to achieve specific objectives. In this study, we utilized an evolutionary algorithm that incorporated mechanical features and biological corrections to construct spider threads with advanced properties capable of efficient and reliable trapping behavior in arbitrary boundary conditions.
View Article and Find Full Text PDFBiological structures possess excellent damage tolerance, which makes them attractive for ballistic protection applications. This paper develops a finite element modelling framework to investigate the performance of several biological structures that are most relevant for ballistic protection, including nacre, conch, fish scales, and crustacean exoskeleton. Finite element simulations were conducted to determine the geometric parameters of the bio-inspired structures that can survive projectile impact.
View Article and Find Full Text PDFStanniocalcin 2 (STC2) has been identified as a prognostic marker in renal cell carcinoma. However, the role of STC2 in renal cell carcinoma is still unclear. In this study, we investigated the relationship between high expression of STC2 and sunitinib resistance in cells and the underlying mechanism.
View Article and Find Full Text PDFJ Mech Behav Biomed Mater
November 2021
The unique, hierarchical patterns of leaf veins have attracted extensive attention in recent years. However, it remains unclear how biological and mechanical factors influence the topology of leaf veins. In this paper, we investigate the optimization mechanisms of leaf veins through a combination of experimental measurements and numerical simulations.
View Article and Find Full Text PDFWorld J Clin Cases
January 2021
Background: Paragonimiasis is a parasitic disease that has multiple symptoms, with pulmonary types being common. According to our clinical practices, the pleural effusion of our patients is full of fibrous contents. Drainage, praziquantel, and triclabendazole are recommended for the treatment, but when fibrous contents are contained in pleural effusion, surgical interventions are necessary.
View Article and Find Full Text PDFThermoplastic polyurethane (TPU) is a polymer material that has high ductility, good biocompatibility and excellent abrasion resistance. These properties open a pathway to manufacturing functional TPU parts for applications in various fields such as aerospace engineering, medical devices and sports equipment. This study aims to investigate the mechanical properties of additively manufactured TPU material affected by three different processing parameters, including build orientation, mix ratio of the new and reused powders and post-processing.
View Article and Find Full Text PDFNumerical investigation into the impact-resistance of complex biological organs remains challenging because of the difficulties in obtaining accurate models and precise material properties. In this work, the elegance of a woodpecker's head, including a slender hyoid connected by a spherical hinge and two revolute hinges, a long upper beak, a short lower beak, and an encephalocoele filled with viscoelastic brain substances, was obtained via a reaction-diffusion based imaging process on the micro-CT data. The material heterogeneity was fully considered in subsequent finite element analysis in LS-Dyna via categorizing the intensity into 53 groups and interpolating their properties from available data of rhamphotheca, hyoid, skull, and beak.
View Article and Find Full Text PDFThe aim of present study is to investigate the feasibility of patient-specific ankle-foot orthoses fabricated using additive manufacturing (AM) techniques. Then, clinical performance of the AFOs manufactured using material PA12 was evaluated in stroke survivors based on gait analysis data. The ankle and foot were scanned by EinScan-Pro 3D scanner.
View Article and Find Full Text PDFLignin-carbohydrate complexes, i.e. LCC-48 and LCC-72 were isolated with vibrational ball milling for 48 h and 72 h, respectively.
View Article and Find Full Text PDFBio-inspired functionally graded cellular materials (FGCM) have improved performance in energy absorption compared with a uniform cellular material (UCM). In this work, sheet-based and strut-based gyroid cellular structures with graded densities are designed and manufactured by stereo-lithography (SLA). For comparison, uniform structures are also designed and manufactured, and the graded structures are generated with different gradients.
View Article and Find Full Text PDFBy curving a rectangular diamondene, an sp /sp composite carbon film, a diamondene nanotube (DNT) can be formed when the two straight edges are sewn together. In this study, thermal stabilities of DNTs are investigated using molecular dynamics simulation approaches. An interesting thermal shrinkage of damaged DNTs is discovered.
View Article and Find Full Text PDFA nano rotation-translation convertor with a deformable rotor is presented, and the dynamic responses of the system are investigated considering the coupling among the van der Waals (vdW), centrifugal and frictional forces. When an input rotational frequency (ω) is applied at one end of the rotor, the other end exhibits a translational motion, which is an output of the system and depends on both the geometry of the system and the forces applied on the deformable part (DP) of the rotor. When centrifugal force is stronger than vdW force, the DP deforms by accompanying the translation of the rotor.
View Article and Find Full Text PDFDiamondene, a carbon nanomaterial containing both sp2 and sp3 carbon atoms, is obtained by compressing two or more layers of graphene. By curving rectangular diamondene and matching the unsaturated C-C bonds on the two unbent edges, a nanotube is built. We build two diamondene nanotubes (DNTs) with different radii and test their strengths under uniaxial tension.
View Article and Find Full Text PDFBeing one of the commonest deformation modes for soft matter, shell buckling is the primary reason for the growth and nastic movement of many plants, as well as the formation of complex natural morphology. On-demand regulation of buckling-induced deformation associated with wrinkling, ruffling, folding, creasing and delaminating has profound implications for diverse scopes, which can be seen in its broad applications in microfabrication, 4D printing, actuator and drug delivery. This paper reviews the recent remarkable developments in the shell buckling of soft matter to explain the most representative natural morphogenesis from the perspectives of theoretical analysis in continuum mechanics, finite element analysis, and experimental validations.
View Article and Find Full Text PDFBackground: Electroacupuncture (EA) is a modern form of acupuncture therapy where stainless steel acupuncture needles are used as percutaneous electrodes to apply electrical stimulation. The concern about electrolytic corrosion of needles during EA has not been conclusively addressed.
Aim: To examine whether corrosion of stainless steel acupuncture needles occurs after EA to establish the safety profile of this therapy.
Background: An ideal placebo design in clinical research should resemble the intervention under investigation to facilitate blinding, yet remain clinically inert. With regard to physical interventions such as acupuncture, a true placebo device has not been developed and validated. Since 1998, researchers have designed several placebo acupuncture devices (PADs).
View Article and Find Full Text PDFA nano continuous variable transmission (nano-CVT) system is proposed by means of carbon nanotubes (CNTs). The dynamic behavior of the CNT-based nanosystem is assessed using molecular dynamics simulations. The system contains a rotary CNT-motor and a CNT-bearing.
View Article and Find Full Text PDFA common spinning toy, called "buzzer", consists of a perforated disk and flexible threads. Despite of its simple construction, a buzzer can effectively transfer translational motions into high-speed rotations. In the present work, we find that the disk can be spun by hand at an extremely high rotational speed, e.
View Article and Find Full Text PDFIn this paper we propose a general method for creating a new type of hierarchical structures at any level in both 2D and 3D. A simple rule based on a rotate-and-mirror procedure is introduced to achieve multi-level hierarchies. These new hierarchical structures have remarkably few degrees of freedom compared to existing designs by other methods.
View Article and Find Full Text PDFThe size effects that reveal the dramatic changes of mechanical behaviour at nanoscales have traditionally been analysed for regular beam systems. Here, the method of using finite-element analysis is explored with the intention of evaluating the size effects for complex nanostructures. The surface elasticity theory and generalized Young-Laplace equation are integrated into a beam element to account for the size effects in classical Euler-Bernoulli and Timoshenko beam theories.
View Article and Find Full Text PDFJ Biomater Sci Polym Ed
February 2017
A new anticoagulant agent was prepared by introducing sulfate groups into corn stover xylan through homogeneous reactions. Three organic solvents, N, N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and formamide (FA), were adopted as reaction media, with the assistance of LiCl. Structural characterization by FT-IR and CNMR showed that xylan sulfate (XS) could be successfully synthesized with SO∙Pyridine (SO∙Py) complexes sulfation reagent in the three media.
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