Effect of time at temperature for natural fibres

The manufacture of natural fibre reinforced polymer matrix composites is generally assumed to be limited to temperatures not exceeding 200°C. However, given the covalent bonding in the various constituents of natural fibres, they should retain properties to an extent dependent on the time at temperature. This study considers fibre mechanical properties after heating in air for various temperatures and times

P-43 Doing Astronomy with Gravitational Waves

With the first detection of gravitational waves on September 14, 2015, the new era of gravitational wave astronomy began. Gravitational wave detections, along with observations made by optical telescopes, have given us new information about the universe. This includes new estimates of the numbers of black holes in the universe and their properties, as well as confirming theories about the sources of some gamma ray bursts and how those sources produce heavy elements

Fractal Dimension: correlate performance to images

Fractal dimension (D or FD) is a measure of the complexity of self-similar data. One common method to quantify an image is to cover the picture with a grid of boxes, count the number of boxes in which the required feature appears, progressively increase the box size and count, then plot the detected feature measurement against box size. The slope of the line is D and the method works for images without self-similarity. The process is a feature of the NIH ImageJ freeware (other packages are available) image processing and analysis software. This technique reduces a processed image to a single real number, even where subjective assessment cannot perceive differences, which can then be used on one axis of a graph. The weave pattern of a woven reinforcement fabric, the permeability of reinforcement fabrics, the strength of fibre-reinforced composites, and reflections from a gel-coated surface have all been found to correlate to D. A rising issue is agglomeration of nanoparticles producing composites with reduced strength compared to uniformly distributed particles, which is normally discussed with qualitative judgement of microstructures, but the variation between images could easily be quantified by FD

All-Sky Search for Continuous Gravitational Waves from Isolated Neutron Stars Using Advanced LIGO O2 Data

We present results of an all-sky search for continuous gravitational waves (CWs), which can be produced by fast spinning neutron stars with an asymmetry around their rotation axis, using data from the second observing run of the Advanced LIGO detectors. Three different semicoherent methods are used to search in a gravitational-wave frequency band from 20 to 1922 Hz and a first frequency derivative from −1×10−8 to 2×10−9  Hz/s. None of these searches has found clear evidence for a CW signal, so upper limits on the gravitational-wave strain amplitude are calculated, which for this broad range in parameter space are the most sensitive ever achieved

The Mechanical Properties of Carbon Fibre With Glass Fibre Hybrid Reinforced Plastics

Merged with duplicate record 10026.1/2475 on 15.03.2017 by CS (TIS)Fibre composite hybrid materials are generally plastics reinforced with two different fibre species. The combination of these three materials (in this thesis they are carbon fibres, glass fibres and polyester resin) allows a balance to be achieved between the properties of the two monofibre composites. Over the fifteen years since the introduction of continuous carbon fibre as a reinforcement, there has been considerable speculation about the "hybrid effect", a synergistic strengthening of reinforced plastics with two fibres when compared with the strength predicted from a weighted average from the component composites. A new equation is presented which predicts the extent of the hybrid effect. Experiments with a variety of carbon-glass hybrids were undertaken to examine the validity of the theory and the effect of the degree of inter-mixing of the fibres. The classification and quantification of the hybrid microstructures was examined with a view to crosscorrelation of the intimacy of mixing and the strength. Mechanical tests were monitored with acoustic emission counting and acoustic emission amplitude distribution equipment. Some specimens were subjected to one thermal cycle to liquid nitrogen temperature prior to testing. Fracture surfaces were examined in the scanning electron microscope. Numerical analysis by finite element methods was attempted. A constant strain triangular element was used initially, but in the later analyses the PAFEC anisotropic isoparametric quadrilateral elements were used. The system was adapted so that a \Ir singularity could be modelled, and post processor software was written to allow nodal averaging of the stresses and the presentation of this data graphically as stress contour maps

In-Mould Gel-Coating for polymer composites

Surface coatings (gel-coats) are often used on commercial composite mouldings for cosmetic and/or durability reasons. They have traditionally been prepared in open moulds with styrene vapour allowed to escape to the workspace and environment. This paper considers the development of in-mould gel-coating processes. A Double Glass Plate Mould (DGPM) was used to prepare flat composite test panels. Laminates were manufactured by liquid composite moulding processes. Conventional hand painted gel-coat, innovative In-Mould Gel-Coating with a trilayer separator fabric (IMGC) or In-Mould Surfacing with a silicone shim (IMS) were studied. The surface quality of the final products was measured using a Wave-Scan device while the adhesion of the gel-coat was characterised by pull-off tests. The new processes offer reasonable properties in a cleaner, more controlled process

Forensic identification of bast fibres

This book focuses on future research directions that will make biocomposites a successful player in the field of high-strength structural applications