Instabilities and soot formation in high pressure explosion flames

Flame instabilities, cellular structures and soot formed in high pressure, rich, spherically expanding iso-octane-air flames have been studied experimentally using high speed Schlieren cinematography, OH fluorescence, and laser induced incandescence. Cellular structures with two wavelength ranges developed on the flame surface. In rich flames with equivalence ratio ?> 1.8, soot was formed in a honeycomb-like structure behind flame cracks associated with the large wavelength cellular structure

The Potential of Critical E-Applications for Engaging SMEs in E Business: A Provider Perspective

YesAgainst a background of the low engagement of SMEs in e-business this paper investigates the emergence of, and potential for, critical e-applications defined as `an e-business application, promoted by a trusted third party, which engages a significant number of SMEs by addressing an important shared business concern within an aggregation.¿ By a review of secondary data and empirical investigation with service providers and other intermediaries the research shows that such applications can facilitate the e-business engagement of SMEs. There are three key findings, namely: the emergence of aggregation specific e-business applications; the emergence of collaboratively based `one to many¿ business models; and the importance of trusted third parties in the adoption of higher complexity e-business applications by SMEs. Significantly this work takes a deliberately provider perspective and complements the already considerable literature on SME IT adoption from a user and network perspective. In terms of future research the importance of a better conceptual understanding of the impact of complexity on the adoption of IT by SMEs is highlighted

Conducting market research using the internet: The case of Xenon laboratories

The way market research is conducted has changed dramatically over the past 30 years, as a result of both the development of the prevailing view of best practice and the state of technology available to researchers. While it is clear that the World Wide Web (WWW) will increasingly be used as a medium for conducting market research, the full implications of this new channel are not yet fully understood. This paper examines the potential for an Internet-based financial services firm (Xenon Laboratories) to analyse conduct market research using the WWW. The case demonstrates that, by employing a novel approach to market research, Xenon Laboratories is in a unique position to understand the charging structures in its market, the market for international payments using credit or charge cards. In doing so, the paper highlights the opportunity to unobtrusively gather market information from an international group of customers by providing Internet-based value-added services

ATTITUDES OF SMALL FARMERS AS 1995 FARM BILL STAKEHOLDERS

Agricultural and Food Policy,

A knowledge based expert system for moulded part design

In today's competitive market many consumer products are designed with complex curved shapes to meet customers' demands for styling and ergonomics. These styled products are commonly manufactured using moulding processes because they can produce a wide range of freeform shapes at relatively low cost. However, although injection moulding and metal casting allow a great deal of design freedom they also make significant demands on the designer to ensure that parts are designed with due regard for manufacturability. This paper describes a knowledge based moulding advisor that has been developed to provide design for moulding advice to designers during the design process. The main contributions of the research are the development of a hierarchical knowledge representation to allow moulding advice to be generated at different levels of detail and the integration of the expert system with a geometric part description extracted from a Computer Aided Design (CAD) solid model. A demonstrator for the manufacturing advisor has been implemented using the expert system shell CLIPS and integrated with CAD using feature recognition. The moulding advisor is able to generate tailored design for moulding advice for a range of manufacturing processes and materials and evaluate the manufacturability of a designed part at the feature level. The paper provides a case study for a simple moulded test part

Instabilities and soot formation in high-pressure, rich, iso-octane-air explosion flames - 1. Dynamical structure

Simultaneous OH planar laser-induced fluorescence (PLIF) and Rayleigh scattering measurements have been performed on 2-bar rich iso-octane–air explosion flames obtained in the optically accessible Leeds combustion bomb. Separate shadowgraph high-speed video images have been obtained from explosion flames under similar mixture conditions. Shadowgraph images, quantitative Rayleigh images, and normalized OH concentration images have been presented for a selection of these explosion flames. Normalized experimental equilibrium OH concentrations behind the flame fronts have been compared with normalized computed equilibrium OH concentrations as a function of equivalence ratio. The ratio of superequilibrium OH concentration in the flame front to equilibrium OH concentration behind the flame front reveals the response of the flame to the thermal–diffusive instability and the resistance of the flame front to rich quenching. Burned gas temperatures have been determined from the Rayleigh scattering images in the range 1.4⩽ϕ⩽1.9 and are found to be in good agreement with the corresponding predicted adiabatic flame temperatures. Soot formation was observed to occur behind deep cusps associated with large-wavelength cracks occurring in the flame front for equivalence ratio ϕ⩾1.8 (C/O⩾0.576). The reaction time-scale for iso-octane pyrolysis to soot formation has been estimated to be approximately 7.5–10 ms

Applying Design for Assembly Principles in Computer Aided Design to Make Small Changes that Improve the Efficiency of Manual Aircraft Systems Installations

The installation of essential systems into aircraft wings involves numerous labour-intensive processes. Many human operators are required to perform complex manual tasks over long periods of time in very challenging physical positions due to the limited access and confined space. This level of human activity in poor ergonomic conditions directly impacts on speed and quality of production but also, in the longer term, can cause costly human resource problems from operators' cumulative development of musculoskeletal injuries. These problems are exacerbated in areas of the wing which house multiple systems components because the volume of manual work and number of operators is higher but the available space is reduced.To improve the efficiency of manual work processes which cannot yet be automated we therefore need to consider how we might redesign systems installations in the enclosed wing environment to better enable operator access and reduce production time.This paper describes a recent study that applied design for assembly and maintainability principles and CATIA v5 computer aided design software to identify small design changes for wing systems installation tasks. Results show positive impacts for ergonomics, production time and cost, and maintainability, whilst accounting for aircraft performance and machining capabilities