Stretchable, Bio-Compatible, Antioxidant and Self-Powering Adhesives from Soluble Silk Fibroin and Vegetal Polyphenols Exfoliated Graphite

The development of bio-glues is still a challenging task, regarding adhesion on wet surfaces; often, high performance and adaption to complex geometries need to be combined in one material. Here, we report biocompatible adhesives obtained by blending regenerated silk (RS) with a soluble plant-derived polyphenol (i.e., chestnut tannin) that was also used to exfoliate graphite to obtain graphene-based RS/tannin (G-RS/T) composites. The resultant G-RS/T hybrid material exhibited outstanding stretchability (i.e., 400%) and high shear strength (i.e., 180 kPa), superior to that of commercial bio-glues, and showed sealant properties for tissue approximation. Moreover, we showed how such nanocomposites exhibit electromechanical properties that could potentially be used for the realization of green and eco-friendly piezoelectric devices. Finally, we demonstrate the in vitro glue’s biocompatibility and anti-oxidant properties that enable their utilization in clinical applications.

Parametric study of I-shaped shear connectors with different orientations in push-out test

A great deal of research has been conducted to improve the understanding of the behavior of new types of shear connectors. This article presents the study of I-shaped connectors behavior under monotonic load welded in four different orientations in order to get the position which gives the high shear strength and the best ductility. For this purpose, eight push-out test specimens with I-shaped shear connectors with different orientations and dimensions were tested in C20/25 and C30/37 concrete classes. The load-slip behavior and failure modes of the tested connectors are presented and discussed. Furthermore, a non-linear 3D finite element modelling of the push-out test is performed in order to further investigate the influencing parameters on the I-shaped connectors behavior. Hence, a parametric study is carried out by using the established 3D finite elements model to study the influence of concrete strength, connector’s steel grade, reinforcements, height and length of the connector. Both experimental and numerical results show that there is a privilege orientation for which the shear strength of an I-shaped shear connector is significantly higher than that of all other tested orientations.

Carbon nanotube-reduced graphene oxide fiber with high torsional strength from rheological hierarchy control

High torsional strength fibers are of practical interest for applications such as artificial muscles, electric generators, and actuators. Herein, we maximize torsional strength by understanding, measuring, and overcoming rheological thresholds of nanocarbon (nanotube/graphene oxide) dopes. The formed fibers show enhanced structure across multiple length scales, modified hierarchy, and improved mechanical properties. In particular, the torsional properties were examined, with high shear strength (914 MPa) attributed to nanotubes but magnified by their structure, intercalating graphene sheets. This design approach has the potential to realize the hierarchical dimensional hybrids, and may also be useful to build the effective network structure of heterogeneous materials.

Chitin–amyloid synergism and their use as sustainable structural adhesives

Chitin, lysozyme, and lysozyme amyloids are evaluated as single-component and composite structural adhesives. A high shear strength is observed for chitin and lysozyme, which can be further improved by at least 25% upon compositing.

Re-weathering of stabilized clay shale with Portland cement behavior

Clay shale is a claystone which in fresh condition has a very high shear strength. When it reacts with the atmosphere or hydrosphere it will weather so that the shear strength of clay shale will drop drastically. The weathering potential of clay shale is generally done by the slake durability test and the weathering process is measured by disintegration ratio test (DR). The strength of clay shale that has fully weathered will increase again when it is stabilized with a minimum of 6% PC (Portland Cement). It was found from the wetting drying cycle process testing that durability of re-weathering of stabilized clay shale with PC is increased compared to natural clay shale. Disintegration ratio of natural clay shale DR was smaller than stabilized clay shale with 6% PC. Additionally, more than 6% PC increased the durability of re-weathering of clay shale.

Selection of cutting parameters for the machinability of Inconel 718 using Grey Relational Analysis

Inconel 718 is considered to be most difficult to machine superalloy because of its high shear strength, work hardening and precipitation hardening. Abrasive particles which are in microstructure have tendency have forming chip to be welded to tool and form built up edge (BUE) making it more difficult to machine. Friction between tool and material and its low thermal conductivity results in high temperature generation. Certain tools such as Ceramics are present which machine this material at prime cutting conditions. This paper addresses the cutting parameters needed most for providing low surface roughness