In situ consolidation of thermoplastic prepreg tape using automated tape placement technology: Potential and possibilities

The key parameters of the in-situ consolidation of carbon fibre reinforced poly-ether-etherketone (AS4-CF/PEEK) by automated tape placement (ATP) process were investigated by manufacturing of continuous rings and by laying tape onto pre-consolidated laminates. In order to establish and understand correlations between the process parameters and mechanical properties, a number of parametric studies were performed by manufacturing and testing the interlaminar shear strength, single lap shear strength and fracture toughness samples. The main process parameters investigated were the compaction force, tape laying speed and tool temperature. To achieve a uniform heat distribution across the thermoplastic tape, a new nozzle was designed. Baseline samples were also manufactured using the autoclave process to provide a comparison for the ATP composites produced. Optical microscopy was used for investigating the microstructure of composites compared. It was found that increasing the tool temperature reduced the temperature gradient between the incoming tape and substrate, resulting in better lap-shear strength and fracture toughness properties

Anaerobic digestion and gasification of seaweed

The potential of algal biomass as a source of liquid and gaseous biofuels is a highly topical theme, with over 70 years of sometimes intensive research and considerable financial investment. A wide range of unit operations can be combined to produce algal biofuel, but as yet there is no successful commercial system producing such biofuel. This suggests that there are major technical and engineering difficulties to be resolved before economically viable algal biofuel production can be achieved. Both gasification and anaerobic digestion have been suggested as promising methods for exploiting bioenergy from biomass, and two major projects have been funded in the UK on the gasification and anaerobic digestion of seaweed, MacroBioCrude and SeaGas. This chapter discusses the use of gasification and anaerobic digestion of seaweed for the production of biofuel

Design, weaving and manufacture of a large 3D composite structures for automotive applications

The Automotive sector is undergoing transformation from conventional metallic materials to textiles manufactured using conventional 2D processing techniques. It is envisaged that although still immature, composite applications into the sector will grow significantly over the next 5 to 10 years and enter more mass market vehicle applications. With the opportunity offered by 3 dimensional advanced flexible materials, the adoption process could be more attractive to Automotive and wider industrial sectors. Currently the benefits of 3D woven preforms are being exploited in the aerospace sector by Safran ltd, with approximately 30% weight reduction over metallic components for the leap fan blade. These reductions in weight due to superior performance are allowing the development of more efficient aerospace components and are leading the way for adoption into the automotive sector. With the need for high speed manufacturing of composite components, it is expected that weaving 3D woven near-net-shapes could offer superior benefits to the automotive sector. Larger scale components have a particular attraction and when manufactured as a one piece woven structure (preform) will offer significant benefits to a wide range of composite applications. Manufacturing composite components is labour intensive with precise placement of multiple layers of pre-impregnated woven plies required. As the composite industries mature, further development of processes is anticipated, with high deposition rates and repeatability high on the priority list. Although many methods of processing from fibre to fabric structure exist, the ability to reduce layup times combined with rapid manufacturing using high speed looms, weaving multilayers at once is an attractive proposition and capable with conventional weaving machines. Traditionally 3D weaving and 3D woven structures have been classed as expensive and slow to process, severely limiting the adoption in to wider end uses and applications. This paper demonstrates how mass manufacturing capability is linked to woven 3D structures and how output and costs in materials manufacture can be further optimised. Initial designs from CAD software were conducted and inputted into a standard weaving loom without Jacquard technology and then a 3D one piece woven structure was obtained. The considerations of weave design, conformability, and permeability were discussed and large scale single- and various-weave one piece woven preform were designed, woven and resin-infused

Ubiquitous Computing and Communication Journal FAIR QUEUE OPTIMIZATION-BASED RESOURCE ALLOCATION ALGORITHM FOR VIDEO TRAFFIC OVER WIRELESS MULTIMEDIA SYSTEM

the main design challenge of suitable medium access control (MAC) protocol for wireless multimedia system is to maximize the utilization of the limited wireless resources while guaranteeing the various QoS requirements for all traffic classes especially for the stringent real-time constraint of real time variable bit rate (rt-VBR) video service. In this paper a novel resource allocation algorithm for video traffic is proposed. The proposed allocation algorithm aims to optimize queue fairing for video packets by minimizing the queue length difference among user’s buffers. At the same time it adaptively controls the allocated resources (bandwidth) for video traffic around the corresponding average bit rate. A minimized control overhead of only two bits is needed to increase the utilization efficiency. Simulation results show that the proposed algorithm achieves very high utilization and allocation efficiency while enhances QoS offered for video traffic and provides nearly fair queuing for video packets. Its efficiency is also investigated under traffic integration condition with voice and data traffic. Under traffic integration condition the data traffic increases the utilization while a good QoS is achieved for all traffic classes