286 research outputs found
A comprehensive review of full cost accounting methods and their applicability to the automotive industry
Full cost accounting has been applied in many industrial settings that include the oil and gas, energy, chemical and waste management industries. Presently, it is not known how it can be applied in an automotive industry context. Therefore, the objective of this paper is to review existing full cost accounting methods and identify an appropriate approach for the automotive sector. This literature review of 4381 papers extracted ten full cost accounting methods with a diverse level of development and consistency in application. Based on a careful examination and critical analysis of each approach and existing automotive sustainability measures, the Sustainability Assessment Model developed by British Petroleum and Aberdeen University has been proposed as a well-developed and potentially practical tool for automotive applications. The Sustainability Assessment Model can be used by both academics and practitioners to translate a range of conflicting sustainability information into a monetary unit score. This is an effective way of communicating trade-offs and outcomes for complex and multi-disciplinary sustainable decisions in the automotive sector. It measures a broad range of economic, environmental, resource and social effects (internal and external), which is currently lacking in existing automotive systems. Its other strengths are the ability to provide both monetary and physical metrics for sustainability assessment, its flexibility and the ability to combine multiple sustainability dimensions. Furthermore, this paper provides helpful clues for researchers interested in exploring full cost accounting in the future by reviewing, analysing and synthesising the broad range of relevant sources from diverse fields in this topic area
Biocomposites for bone tissue engineering : innovation report
Historically, bone defects resulting from trauma, disease or infection are treated with autograft or allograft. Autograft is bone transplanted from a non-critical area of the skeleton and allograft is bone donated from another member of the same species. The drawbacks with these treatments such as limited availability, donor site morbidity, high cost and disease transmission have driven increasing use of bone graft substitute (BGS) materials. These represent 15% of the £1.6 billion global orthobiologics market. BGS materials available to date are not suitable for use in grafts that are intrinsic to the stability of the skeleton. Thus, the aim for this project was to fabricate an off the shelf and economically viable BGS that will support the skeletal structure whilst healing occurs. This project employed an empirical approach utilising both rapid prototyping (RP) and conventional manufacturing processes to produce novel BGSs. A range of RP techniques were attempted and discovered to be unsuitable as a result of their long build and postprocessing times, poor availability of suitable materials, and undesirable surface finish. Experiments with injection moulding and laser drilling of polylactic acid (PLA) successfully produced 10 mm blocks with a compressive strength of 67 – 80 MPa and compressive modulus of 1.5 – 2.2 GPa. This line of research led to the hypothesis that ceramic extrusion, a process hitherto untested for use in bone tissue engineering (BTE), may be feasible for production of a novel and high strength BGS. In collaboration with an international expert in the manufacture of ceramic monoliths it was possible, for the first time, to manufacture hydroxyapatite (HA) monoliths by adapting the process used for manufacture of automotive exhaust catalysts. These HA monoliths exhibited a compressive strength of 142 – 265 MPa and compressive modulus of 3.2 – 4.4 GPa. The exceptional strength of these monoliths match the properties of cortical bone whilst retaining the high levels of porosity (> 60 %) found in cancellous bone. This combination of strength and porosity will enable treatment of large structural bone defects where the high strength will withstand typical skeletal forces whilst the high porosity allows blood vessels to infiltrate the monolith and begin the healing process. Furthermore, these HA monoliths support the proliferation and differentiation of human osteoblast-like MG63 cells and compare very favourably with a market leading BGS material in terms of their biological performance. It is suggested that this work will result in the development of a new family of high strength and high porosity BGSs for use in challenging clinical situations. The International Preliminary Examination Report for the patent issued to the author (WO 2007/125323) decreed that all 45 claims contained novelty and an inventive step. Two successful applications for research funding have raised nearly £50,000 that helped fund this research effort. Warwick ventures are currently involved in negotiating with medical partners to licence this technology for clinical use.EThOS - Electronic Theses Online ServiceEngineering and Physical Sciences Research Council (EPSRC)Spinner (Firm)Warwick Innovative Manufacturing Research CentreGBUnited Kingdo
Sustainable development model for measuring and managing sustainability in the automotive sector
A growing number of organizations across a variety of industries are now pursuing sustainable management business goals to improve business efficiency, manage stakeholder expectations, or for legislative compliance. This is also the case for automotive manufacturing organizations who are under pressure from their stakeholders to manage and improve sustainability performance. This requires the development of credible measurement tools and systems to enable capture and monitoring of sustainability. This paper describes the development process for an innovative model, named the Automotive Sustainability Assessment Model (A-SAM), to drive sustainable decision-making in the automotive sector. The process of developing the model consisted of four major steps, each of which contained series of intermediate steps, individual objectives, and research methods. The model measures, quantifies, and translates a broad range of external effects (both positive and negative) into their monetary equivalents, enabling large car manufacturers to evaluate options, identify win–wins, and optimize trade-off, while making complex and multidisciplinary sustainability decisions. It allows managers and design engineers in the automotive sector to develop a better understanding of the environmental, resource, and social impacts of their activities, products, processes, and materials used, while still ensuring cost-effectiveness when making decisions. The A-SAM shows promise as an effective tool for supporting sustainability decisions in a business environment. Although developed in the context of the automotive industry, it can be adapted by organizations of any type, operating across many different sectors for managing sustainability in a more holistic, comprehensive, and integrated manner
The use of a complexity model to facilitate in the selection of a fuel cell assembly sequence
Various tools and methods exists for arriving at an optimised assembly sequence with most using a soft computing approach. However, these methods have issues including susceptibly to early convergence and high computational time. The typical objectives for these methods are to minimise the number of assembly change directions, orientation changes or the number of tool changes. This research proposes an alternative approach whereby an assembly sequence is measured based on its complexity. The complexity value is generated using design for assembly metrics and coupled with considerations for product performance, component precedence and material handling challenges to arrive at a sequence solution which is likely to be closest to the optimum for cost and product quality. The case presented in this study is of the assembly of a single proton exchange membrane fuel cell. This research demonstrates a practical approach for determining assembly sequence using data and tools that are used and available in the wider industry. Further work includes automating the sequence generation process and extending the work by considering additional factors such as ergonomi
Hydrogen fuel cell pick and place assembly systems : heuristic evaluation of reconfigurability and suitability
Proton Exchange Membrane Fuel Cells (PEMFCs) offer numerous advantages over combustion technology but they remain economically uncompetitive except for in niche applications. A portion of this cost is attributed to a lack of assembly expertise and the associated risks. To solve this problem, this research investigates the assembly systems that do exist for this product and systematically decomposes them into their constituent components to evaluate reconfigurability and suitability to product. A novel method and set of criteria are used for evaluation taking inspiration from heuristic approaches for evaluating manufacturing system complexity. It is proposed that this can be used as a support tool at the design stage to meet the needs of the product while having the capability to accept potential design changes and variants for products beyond the case study presented in this work. It is hoped this work develops a new means to support in the design of reconfigurable systems and form the foundation for fuel cell assembly best practice, allowing this technology to reduce in cost and find its way into a commercial space
Predicted distribution of High Nature Value farmland in the Republic of Ireland
peer-reviewedHigh Nature Value (HNV) farmland is typically characterised by low-intensity farming associated with high biodiversity and species of conservation concern. Mapping the occurrence and distribution of such farmland are useful for appropriate targeting of conservation measures and supporting associated rural communities. We mapped the likely distribution of HNV farmland in the Republic of Ireland using a linear regression model incorporating established European indicators, adapted for Ireland and weightings based on expert opinion. The indicators used were semi-natural habitat cover, stocking density, hedgerow density, river and stream density and soil diversity, with highest weightings placed on the first two indicators (40% and 30%, respectively). The map provides information on the likely occurrence and distribution of HNV farmland in each electoral division as a reference point for future monitoring of the distribution of HNV farmland in the Republic of Ireland in order to assist with planning and policy development for the rural environment.This study was conducted by Teagasc and IT Sligo as part of the IDEAL-HNV project [Ref. 11/S/108], funded by the Department of Agriculture, Food and the Marine (DAFM)
under the National Development Plan 2007–2013
A framework for automatically realizing assembly sequence changes in a virtual manufacturing environment
Global market pressures and the rapid evolution of technologies and materials force manufacturers to constantly design, develop and produce new and varied products to maintain a competitive edge. Although virtual design and engineering tools have been key to supporting this fast rate of change, there remains a lack of seamless integration between and within tools across the domains of product, process, and resource design - especially to accommodate change. This research examines how changes to designs within these three domains can be captured and evaluated within a component based engineering tool (vueOne, developed by the Automation Systems Group at the University of Warwick). This paper describes how and where data within these tools can be mapped to quickly evaluate change (where typically a tedious process of data entry is required) decreasing lead times and cost and increasing productivity. The approach is tested on a sub-assembly of a hydrogen fuel cell, where an assembly system is modelled and changes are made to the sequence which is translated through to control logic. Although full implementation has not yet been realized, the concept has the potential to radically change the way changes are made and the approach can be extended to supporting other change types provided the appropriate rules and mapping
Effects of tool coating and tool wear on the surface quality and flexural strength of slotted CFRP
Machining of carbon fibre reinforced polymer (CFRP) is abrasive and causes significant tool wear. The effect of tool wear on static flexural strength is investigated, using edge trimming with uncoated carbide and chemical vapour deposition (CVD) diamond coated burr style tools. Edge rounding (ER) criteria along with flank wear are used to observe tool degradation with ER shown to preferentially wear allowing the tool to become cyclically sharper and duller, corresponding to fluctuating dynamometer readings, a novelty for CFRP machining. Areal surface metrics degraded for an uncoated tool due to changes in cutting mechanism, whilst for up to 16.2 m of linear traverse, the coated tool showed limited changes. Tool wear, caused by edge trimming 7.2 m of CFRP, using an uncoated carbide tool, provided a flexural strength reduction of up to 10.5 %, directly linking tool wear to reduced mechanical strength
Ecological homogenization of oil Properties in the American Residential Macrosystem
The conversion of native ecosystems to residential ecosystems dominated by lawns has been a prevailing land-use change in the United States over the past 70 years. Similar development patterns and management of residential ecosystems cause many characteristics of residential ecosystems to be more similar to each other across broad continental gradients than that of former native ecosystems. For instance, similar lawn management by irrigation and fertilizer applications has the potential to influence soil carbon (C) and nitrogen (N) pools and processes. We evaluated the mean and variability of total soil C and N stocks, potential net N mineralization and nitrification, soil nitrite (NO2−)/nitrate (NO3−) and ammonium (NH4+) pools, microbial biomass C and N content, microbial respiration, bulk density, soil pH, and moisture content in residential lawns and native ecosystems in six metropolitan areas across a broad climatic gradient in the United States: Baltimore, MD (BAL); Boston, MA (BOS); Los Angeles, CA (LAX); Miami, FL (MIA); Minneapolis–St. Paul, MN (MSP); and Phoenix, AZ (PHX). We observed evidence of higher N cycling in lawn soils, including significant increases in soil NO2−/NO3−, microbial N pools, and potential net nitrification, and significant decreases in NH4+ pools. Self-reported yard fertilizer application in the previous year was linked with increased NO2−/ NO3− content and decreases in total soil N and C content. Self-reported irrigation in the previous year was associated with decreases in potential net mineralization and potential net nitrification and with increases in bulk density and pH. Residential topsoil had higher total soil C than native topsoil, and microbial biomass C was markedly higher in residential topsoil in the two driest cities (LAX and PHX). Coefficients of variation for most biogeochemical metrics were higher in native soils than in residential soils across all cities, suggesting that residential development homogenizes soil properties and processes at the continental scale
Ecological Homogenization of Urban USA
A visually apparent but scientifically untested outcome of land-use change is homogenization across urban areas, where neighborhoods in different parts of the country have similar patterns of roads, residential lots, commercial areas, and aquatic features. We hypothesize that this homogenization extends to ecological structure and also to ecosystem functions such as carbon dynamics and microclimate, with continental-scale implications. Further, we suggest that understanding urban homogenization will provide the basis for understanding the impacts of urban land-use change from local to continental scales. Here, we show how multi-scale, multi-disciplinary datasets from six metropolitan areas that cover the major climatic regions of the US (Phoenix, AZ; Miami, FL; Baltimore, MD; Boston, MA; Minneapolis–St Paul, MN; and Los Angeles, CA) can be used to determine how household and neighborhood characteristics correlate with land-management practices, land-cover composition, and landscape structure and ecosystem functions at local, regional, and continental scales
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