Elastic deformability and luminescence of crystals of polyhalogenated platinum(II)-bipyridine complexes

Single crystals showing elastic or plastic flexibility have attracted increasing attention as next-generation soft materials. Herein, we successfully developed a series of polyhalogenated platinum(II)-bipyridine complexes showing solvent-of-crystallisation-dependent elastic flexibility. Notably,...

Approaching diamond’s theoretical elasticity and strength limits

Diamond is the hardest natural material, but its practical strength is low and its elastic deformability extremely limited. While recent experiments have demonstrated that diamond nanoneedles can sustain exceptionally large elastic tensile strains with high tensile strengths, the size- and orientation-dependence of these properties remains unknown. Here we report maximum achievable tensile strain and strength of diamond nanoneedles with various diameters, oriented in <100>, <110> and <111> -directions, using in situ transmission electron microscopy. We show that reversible elastic deformation depends both on nanoneedle diameter and orientation. <100> -oriented nanoneedles with a diameter of 60 nm exhibit highest elastic tensile strain (13.4%) and tensile strength (125 GPa). These values are comparable with the theoretical elasticity and Griffith strength limits of diamond, respectively. Our experimental data, together with first principles simulations, indicate that maximum achievable elastic strain and strength are primarily determined by surface conditions of the nanoneedles.

A Characteristic of Selected Properties of Vulcanised Rubber Elements Used on the “Izabel” Inland Vessel

Vulcanised rubber as a complex system is made from the basic component being virgin rubber and various components amounting to 10-15 per cent or even more. The material gains its most valuable properties in the final phase of processing i.e. vulcanisation. In mechanical as well as automotive engineering it is important for vulcanised rubber to be resistant to grease, oil and fuel in high operating temperatures. Being one of the very valuable isolation materials, vulcanised rubber is also characterised by dielectric and elastic properties as well as distinguished resistance to operating conditions (high/low temperature, weather conditions). All the above mentioned applications of vulcanised rubbers are also found in the shipyard industry. Their use is also very much predicated on the properties such as: ability to attenuate mechanical vibrations, high elasticity, considerable elastic deformability under static and dynamic loads, low permeability of water and gas, resistance to various chemicals, and other. The purpose of this article was to determine the hardness of vulcanised rubber samples obtained from various places on the “Izabel” inland barge. The scope of the study covered sampling and preparing the samples for testing (i.e. cleaning and degreasing the samples). Then, the hardness of the samples was measured using the Shore hardness test. The first part of the article presents the general concept of vulcanised rubber, its main components, properties, applications, and ageing. The second part focuses on the research scope and measuring the hardness of vulcanised rubber samples obtained from the “Izabel” inland barge.

The Experimental Validation of Pseudoelastic Shape Memory Sheet Elements in Tooling Applications

Shape memory alloys (SMA) are capable to remember a previously programmed form even after strong deformation. The reversible deformation of pseudoelastic SMA takes place on the basis of stress-induced martensitic phase transformation. These alloys are also interesting for elastic spring and damping elements, making their use in a variety of different machining and tool applications conceivable. Examples are elastic spring elements in forceps or damping elements in the field of sawing applications. The use of sheet like pseudoelsatic elements is of particular relevance for applications in handheld- and machining-tools. High elastic deformability, the damping properties and the potential of setting a horizontal spring characteristic curve in SMA elements come with problems such as strong temperature dependence of the spring and damping characteristics, possible limitations on the durability due to aging effects in cyclically occurring loads. Therefore, it requires a more extensive characterization and validation of sheet-shaped NiTi spring and damping elements. Hence different sheet-shaped SMA elements are analyzed in this publication due to different bends and thicknesses as well as different heat treatments for programming shapes into the sheets. Prepared sheets are characterized, especially cycle dependent force to displacement and damping properties. The publication shows experimental results of this analysis for various SMA sheets and potential industrial applications in the field of machine tools.

Increased Collagen Mineralization Affects the Yield Stress But Not the Yield Strain in Cortical Bone of Rats: Implications for Age-Related Tissue Embrittlement

It has been well documented that the fracture susceptibility of cortical bone increases significantly with age [1]. Although the age-related decline in the fracture resistance of the cortical bone is attributed to reduced bone quantity; a substantial overlap in the bone mass of normal subjects and those sustaining fractures suggests that bone mass alone does not identify the fracture risk on an individual basis [2]. Therefore, the conceptual framework should be improved to include bone quality measures in addition to bone quantity to refine fracture risk assessment. In this study, Raman microspectroscopy was used to assess two key variables of bone tissue quality in aging rat cortical bone: the relative amount of mineral with respect to the amount of collagen (i.e. collagen mineralization) and the mineral crystallinity (i.e. size and stoichiometric perfection of mineral crystals). In this regard the first aim of this study was to investigate age-related changes in the extent of mineralization of collagen fibers and to test its relationship to elastic deformability of cortical bone tissue. The second aim of the study was to investigate age-related changes in the mineral crystallinity and to test its relationship to elastic deformability of cortical bone tissue. The first hypothesis of this study is that both collagen mineralization and mineral crystallinity will increase with age. The second hypothesis of this study was that age-related changes in compositional properties will compromise the elastic deformation capacity of cortical bone tissue.

Tolerance Analysis of Deformable Assemblies

This article describes the use of a mechanical approach taking deformation into account in the computation of tolerances for welded, riveted, bolted or glued assemblies of sheetmetal parts. Integration of the FEM to model the elastic deformability in the assembly process results in a finer and more realistic simulation. Both analysis and synthesis tools can be based on this approach.