Top Arc Seam Weld Shear Strength and Stiffness for Sheet-to-sheet Connections

The North American Specification for the Design of Cold-Formed Steel Structural Members does not provide specific design guidance for sheet-to-sheet top arc seam welds in shear. A collaborative industry study has developed design guidance for both strength and stiffness of the connection to facilitate analytical evaluation of floor and roof diaphragm assemblies and wall assemblies. The test program was performed per AISI S905 and addressed material ductility, weld length, sheet thickness and the distribution of the force being transferred by the weld connection

Nitrogen incorporation and optical studies of GaAsSbN/GaAs single quantum weil heterostructures

Cataloged from PDF version of article.In this work, the effects of N incorporation on the optical properties of GaAsSbN/GaAs single quantum wells (SQWs) have been investigated using temperature, excitation, and magnetic dependencies of photoluminescence (PL) characteristics. These layers were grown in an elemental solid source molecular beam epitaxy system with a rf plasma N source. The N concentrations in the range of 0.5%-2.5% were investigated in this study. The SQW with N similar to 0.5% exhibits a behavior similar to that in an intermediate regime where the contributions from the localized states in the band gap are dominant. The temperature and excitation dependencies of the PL characteristics indicate that for the N concentration of 0.9% and above, the alloy behavior is analogous to that of a regular alloy and the changes in optical properties are only marginal. The conduction band effective mass (m(eff)) values computed from the magnetophotoluminescence spectra using a variational formalism and the band anticrossing model are in good agreement and indicate enhanced values of m(eff). However, there is no significant variation in m(eff) values of QWs for N >= 0.9%. Small redshift of about 30-50 meV for the temperature variations from 10 to 300 K in conjunction with unusually small blueshift observed in the excitation dependence of PL for N >= 0.9% indicate that this system holds a great promise for laser applications at 1.55 mu m and beyond

Abrasive water jet drilling of advanced sustainable bio-fibre-reinforced polymer/hybrid composites : a comprehensive analysis of machining-induced damage responses

This paper aims at investigating the effects of variable traverse speeds on machining-induced damage of fibre-reinforced composites, using the abrasive water jet (AWJ) drilling. Three different types of epoxy-based composites laminates fabricated by vacuum bagging technique containing unidirectional (UD) flax, hybrid carbon-flax and carbon fibre-reinforced composite were used. The drilling parameters used were traverse speeds of 20, 40, 60 and 80 mm/min, constant water jet pressure of 300 MPa and a hole diameter of 10 mm. The results obtained depict that the traverse speed had a significant effect with respect to both surface roughness and delamination drilling-induced damage responses. Evidently, an increase in water jet traverse speed caused an increase in both damage responses of the three samples. Significantly, the CFRP composite sample recorded the lowest surface roughness damage response, followed by C-FFRP, while FFRP exhibited the highest. However, samples of FFRP and hybrid C-FFRP recorded lowest and highest delamination damage responses, respectively. The discrepancy in both damage responses, as further validated with micrographs of colour video microscopy (CVM), scanning electron microscopy (SEM) and X-ray micro-computed tomography (X-ray μCT), is attributed to the different mechanical properties of the reinforced fibres, fibre orientation/ply stacking and hybridisation of the samples.Peer reviewe

Rewriting DNA Methylation Signatures at Will:The Curable Genome Within Reach?

DNA methyltransferases are important enzymes in a broad range of organisms. Dysfunction of DNA methyltransferases in humans leads to many severe diseases, including cancer. This book focuses on the biochemical properties of these enzymes, describing their structures and mechanisms in bacteria, humans and other species, including plants, and also explains the biological processes of reading of DNA methylation and DNA demethylation. It covers many emerging aspects of the biological roles of DNA methylation functioning as an essential epigenetic mark and describes the role of DNA methylation in diseases. Moreover, the book explains modern technologies, like targeted rewriting of DNA methylation by designed DNA methyltransferases, as well as technological applications of DNA methyltransferases in DNA labelling. Finally, the book summarizes recent methods for the analysis of DNA methylation in human DNA. Overall, this book represents a comprehensive state-of-the-art- work and is a must-have for advanced researchers in the field of DNA methylation and epigenetics

Tuned thermoelectric properties of TiS1.5Se 0.5 through copper intercalation

Polycrystalline samples of copper intercalated Cux TiS1.5Se 0.5 (x = 0, 0.025, 0.05 and 0.1) are synthesized by classical high temperature reaction. The resulting powders are successfully densified by using spark plasma sintering. As expected, XRD refinements show that Cu intercalation between TiS1.5Se 0.5 slabs induces an increase in the c lattice parameter. Electrical resistivity and Seebeck coefficient decrease drastically with increasing Cu content, direct consequence of the increased carrier concentration. In parallel, the lattice thermal conductivity of CuxTiS1.5Se 0.5 is significantly reduced compared to unfilled TiS1.5Se 0.5. Overall, the dimensionless thermoelectric figure of merit increases with temperature and reaches a maximum value of 0.54 at 700 K for Cu0.05TiS1.5Se 0.5, the highest value so far observed in layered titanium chalcogenides. © 2015 Elsevier B.V. All rights reserved