Plasma simulation using the massively parallel processor

Two dimensional electrostatic simulation codes using the particle-in-cell model are developed on the Massively Parallel Processor (MPP). The conventional plasma simulation procedure that computes electric fields at particle positions by means of a gridded system is found inefficient on the MPP. The MPP simulation code is thus based on the gridless system in which particles are assigned to processing elements and electric fields are computed directly via Discrete Fourier Transform. Currently, the gridless model on the MPP in two dimensions is about nine times slower that the gridded system on the CRAY X-MP without considering I/O time. However, the gridless system on the MPP can be improved by incorporating a faster I/O between the staging memory and Array Unit and a more efficient procedure for taking floating point sums over processing elements. The initial results suggest that the parallel processors have the potential for performing large scale plasma simulations

Energy consumption and capacity utilization of galvanizing furnaces

An explicit equation leading to a method for improving furnace efficiency is presented. This equation is dimensionless and can be applied to furnaces of any size and fuel type for the purposes of comparison. The implications for current furnace design are discussed. Currently the technique most commonly used to reduce energy consumption in galvanizing furnaces is to increase burner turndown. This is shown by the analysis presented here actually to worsen the thermal efficiency of the furnace, particularly at low levels of capacity utilization. Galvanizing furnaces are different to many furnaces used within industry, as a quantity of material (in this case zinc) is kept molten within the furnace at all times, even outside production periods. The dimensionless analysis can, however, be applied to furnaces with the same operational function as a galvanizing furnace, such as some furnaces utilized within the glass industry. © IMechE 2004

Creative haptics: an evaluation of a haptic tool for non-sighted and visually impaired design students, studying at a distance

Design students who are blind or sight-impaired face distinct challenges when studying a visually centric discipline such as design practice. Students who are sighted use computer-aided design (CAD) which is presented via high definition using a PC mouse. However, design students who are blind or sight-impaired are not able to use visual display technology; therefore, this creates a barrier to access for this community. The aim of this study is to present a haptic prototype trial (Haptic Application Prototype Test [HAPT]) designed to assist design students who are blind/sight-impaired to interact with prototype assembly at the Open University (OU). The study specifically assessed the user feedback and the efficacy of access to CAD interface through the affordances of the haptic interface. The experiment included two groups of participants: one group included students who were blind and sight-impaired and the second group students who were classed fully sighted. Both groups were tested in two conditions of haptic engagement – manual and virtual. The parameters examined were (a) time – set at an industry-recognized time taken to assemble a ‘sketch model’ or prototype, and (b) ncollision – the number of collisions created by a collision algorithm which calculated any random collisions with the virtual environment or objects therein. Quantitative results showed that there was little statistical difference between time and a between-group test. From this we can imply that the haptic interface had offered equal access to CAD for people in the trial who were sighted and blind/sight-impaired indiscriminate of their sight acuity. Further future work using HAPT could be developed to a wider audience and a larger more diverse range of sight-impaired users. Future work will focus on new explorations of teaching using of haptics for greater immersion for distance learners at the OU science, technology, engineering and mathematics (STEM) labs

Heterogeneously catalyzed lignin depolymerization

Biomass offers a unique resource for the sustainable production of bio-derived chemical and fuels as drop-in replacements for the current fossil fuel products. Lignin represents a major component of lignocellulosic biomass, but is particularly recalcitrant for valorization by existing chemical technologies due to its complex cross-linking polymeric network. Here, we highlight a range of catalytic approaches to lignin depolymerisation for the production of aromatic bio-oil and monomeric oxygenates

Review on catalytic cleavage of C-C inter-unit linkages in lignin model compounds: Towards lignin depolymerisation

Lignin depolymerisation has received considerable attention recently due to the pressing need to find sustainable alternatives to fossil fuel feedstock to produce chemicals and fuels. Two types of interunit linkages (C–C and C–O linkages) link several aromatic units in the structure of lignin. Between these two inter-unit linkages, the bond energies of C–C linkages are higher than that of C–O linkages, making them harder to break. However, for an efficient lignin depolymerisation, both types of inter-unit linkages have to be broken. This is more relevant because of the fact that many delignification processes tend to result in the formation of additional C–C inter-unit bonds. Here we review the strategies reported for the cleavage of C–C inter-unit linkages in lignin model compounds and lignin. Although a number of articles are available on the cleavage of C–O inter-unit linkages, reports on the selective cleavage of C–C inter-unit linkages are relatively less. Oxidative cleavage, hydrogenolysis, two-step redox-neutral process, microwave assisted cleavage, biocatalytic and photocatalytic methods have been reported for the breaking of C–C inter-unit linkages in lignin. Here we review all these methods in detail, focused only on the breaking of C–C linkages. The objective of this review is to motivate researchers to design new strategies to break this strong C–C inter-unit bonds to valorise lignins, technical lignins in particular