Search

The composition of friction materials is being revolutionised to exclude contentious components. This work comparatively used palm kernel shells, maize husks, cocoa bean shells and melon shells separately with seven other component materials to achieve novel friction materials. Friction and wear of the friction materials were measured using the test rig designed and constructed in-house for this research. Results showed that the maize husk-based friction material performed greatest in terms of thermal stability, wear, porosity and water absorption. Their thermal stability level indicates suitability for use in low-speed passenger cars and other allied braking applications. Using the selected agricultural residues in place of the contentious components in traditional friction materials would potentially solve health and environmental safety challenges. [ABSTRACT FROM AUTHOR]

Thermosets and composites were prepared from blends of epoxidized waste vegetable oils and diglycidyl ether of bisphenol-A to investigate this material as an alternative triglyceride source for epoxy resins. Purification of the waste oil was developed to remove impurities derived from thermal degradation in the frying process and different epoxidation methodologies were investigated. Effects of epoxidized vegetable oil content (up to 30 wt%) and origin on the tensile properties were studied and revealed that purified waste oils performed similarly to neat oil in contents up to 10 wt%, proving that this strategy does not compromise tensile properties when waste oils are used in suitable proportions. Furthermore, a more prominent plasticizing effect was observed when more than 15 wt% of bio-based resin was used as confirmed by DMA. Composites were prepared with recycled carbon fibres (up to 30 wt%) and thermosets with 10 wt% of bio-based epoxy resins, significantly improving the mechanical properties. [ABSTRACT FROM AUTHOR]

The variability in viscosity and combustion quality has been identified from the literature as a barrier to the use of biodiesel fuels in motorsport. These parameters can affect performance, emissions and fuel consumption. Diesel engines have had recent success in endurance and touring car racing; biodiesel is an opportunity to increase the sustainability of this emerging area of motorsport. Methyl esters from rapeseed, soybean and sunflower oils were tested alongside EN 590 diesel fuel. Variations in fuel consumption, output torque and power were observed between the fuels. Further tests were carried out on an automotive diesel engine to evaluate the in–cylinder pressures for soybean B100, beef tallow B50 and EN 590 to gain understanding of the reasons behind the performance differences noted in the initial tests. Retarding the start of injection for B50 and B100 biodiesel improved the peak torque by up to 5% enabling the production of equal torque at the same engine speed when compared to EN 590 but with lower peak in–cylinder pressure and a shorter ignition delay. The application of this to motorsport is the potential to achieve higher peak power outputs; the shorter ignition delay and more rapid combustion has the potential to be used to raise the maximum engine speed and therefore the peak power output of diesel engines for motorsport. [ABSTRACT FROM AUTHOR]

Business efficiency, stakeholder pressure and the need for legislative compliance compel the automotive sector to design and manufacture fuel-efficient, low-impact, environmentally responsible and sustainable vehicles. Managing and responding to these multiple and sometimes conflicting interests requires the measurement of economic, environmental and societal performance. Although a number of automotive sustainability measures are mentioned within the literature, there is no single and unique approach for the complete and integrated sustainability assessment of vehicles. This study has developed a comprehensive automotive sustainability assessment framework by selecting a set of sustainability assessment criteria from the literature and refining these through an interview study with 24 automotive experts from academia, car manufacturers, consultancies and non-governmental organisations. Based on this approach, 26 midpoint and 9 end-point environmental, resource, social and economic impact categories have been identified for the construction of a framework for automotive sustainability assessment. The proposed framework can be used as a decision-supporting tool at the early stages of the vehicle development process. It allows source and sustainability issues to be identified throughout the entire vehicle life cycle and provides the means to sharpen analysis and discussion around these issues. The framework can also serve as a design structure for a wide range of sustainability assessment methods and tools (e.g. multi-criteria decision adding or sustainability accounting methods). It serves as guidance on what needs to be measured in an integrated sustainability assessment of vehicles and leaves the choice of what to include in the decision-making process to the discretion of individual companies. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Sustainability assessments require the management of a wide variety of information types, parameters and uncertainties. Multi criteria decision analysis (MCDA) has been regarded as a suitable set of methods to perform sustainability evaluations as a result of its flexibility and the possibility of facilitating the dialogue between stakeholders, analysts and scientists. However, it has been reported that researchers do not usually properly define the reasons for choosing a certain MCDA method instead of another. Familiarity and affinity with a certain approach seem to be the drivers for the choice of a certain procedure. This review paper presents the performance of five MCDA methods (i.e. MAUT, AHP, PROMETHEE, ELECTRE and DRSA) in respect to ten crucial criteria that sustainability assessments tools should satisfy, among which are a life cycle perspective, thresholds and uncertainty management, software support and ease of use. The review shows that MAUT and AHP are fairly simple to understand and have good software support, but they are cognitively demanding for the decision makers, and can only embrace a weak sustainability perspective as trade-offs are the norm. Mixed information and uncertainty can be managed by all the methods, while robust results can only be obtained with MAUT. ELECTRE, PROMETHEE and DRSA are non-compensatory approaches which consent to use a strong sustainability concept, accept a variety of thresholds, but suffer from rank reversal. DRSA is less demanding in terms of preference elicitation, is very easy to understand and provides a straightforward set of decision rules expressed in the form of elementary “if … then …” conditions. Dedicated software is available for all the approaches with a medium to wide range of results capability representation. DRSA emerges as the easiest method, followed by AHP, PROMETHEE and MAUT, while ELECTRE is regarded as fairly difficult. Overall, the analysis has shown that most of the requirements are satisfied by the MCDA methods (although to different extents) with the exclusion of management of mixed data types and adoption of life cycle perspective which are covered by all the considered approaches. [ABSTRACT FROM AUTHOR]

Abstract: During the cultivation of mushrooms on straw, the degradation of lignocellulose takes place under the action of enzymes releasing degradation products with small molecular weight, some of which are potentially valuable (sugars, phenolics, fatty acids, etc). These compounds may be extracted from straw after mushroom cultivation in two stages: an aqueous extraction followed by a solvent extraction. The present work is focused on the first stage of the process where water soluble compounds are extracted. It is important to conduct experiments at a scale that would reflect the amount of waste straw generated by a mushroom farm. A study was performed using a vessel of 300 L capacity with mixing impeller, by observing the influence of the temperature, extraction time and water-to-dry straw ratio on the total extracted matter and especially on sugar and phenolic compounds yields. The optimum extraction conditions were determined by taking into account the yields. From this study, it emerged that the room temperature is recommended, the water-to-straw ratio would not exceed 40:1 kg kg−1 of dry straw and the extraction time should be limited to 4 h. [Copyright &y& Elsevier]

• MECs are a novel wastewater treatment technology, producing hydrogen gas. • Recycled carbon fibre (rCF) can be an inexpensive alternative anode material. • MECs with rCF anodes perform significantly better than MECs using graphite anodes. • Normalised rCF anode MEC H 2 gas = 66 L d−1 m−3; Graphite = 3.6 L d−1 m−3. • rCF anodes are up to 93% less expensive than similar graphite anodes. Growing energy demands of wastewater treatment have made it vital for water companies to develop less energy intensive processes for treating wastewater if net zero emissions are to be achieved by 2050. Microbial electrolysis cells (MECs) have the potential to do this by treating water and producing renewable hydrogen gas as a product, but capital and operational costs have slowed their deployment. By using recycled carbon fibre mats, commercially viable MECs can brought closer to reality, where recycled carbon fibre anode MECs treating real wastewater (normalised ~3100 L d−1) were producing 66.77 L H 2 d−1 while graphite felt anode MECs produced 3.65 L H 2 d−1 per 1 m3 reactor, anodes costing £5.53 m−2 and £88.36 m−2 respectively, resulting in a total anode cost saving of 93%. This could incentivise the development of larger pilot systems, opening the door for generating greater value and a more sustainable wastewater treatment industry. [ABSTRACT FROM AUTHOR]

This paper proposes a robustness analysis based on Multiple Criteria Decision Aiding (MCDA). The ensuing model was used to assess the implementation of green chemistry principles in the synthesis of silver nanoparticles. Its recommendations were also compared to an earlier developed model for the same purpose to investigate concordance between the models and potential decision support synergies. A three-phase procedure was adopted to achieve the research objectives. Firstly, an ordinal ranking of the evaluation criteria used to characterize the implementation of green chemistry principles was identified through relative ranking analysis. Secondly, a structured selection process for an MCDA classification method was conducted, which ensued in the identification of Stochastic Multi-Criteria Acceptability Analysis (SMAA). Lastly, the agreement of the classifications by the two MCDA models and the resulting synergistic role of decision recommendations were studied. This comparison showed that the results of the two models agree between 76% and 93% of the simulation set-ups and it confirmed that different MCDA models provide a more inclusive and transparent set of recommendations. This integrative research confirmed the beneficial complementary use of MCDA methods to aid responsible development of nanosynthesis, by accounting for multiple objectives and helping communication of complex information in a comprehensive and traceable format, suitable for stakeholders and/or decision-makers with diverse backgrounds. [ABSTRACT FROM AUTHOR]

Nanotechnology applications (nanoproducts) have entered the market or are expected to do so in the near future. Robust and science-based criteria are required to appraise and manage their sustainability. This paper describes the approach used to develop a comprehensive and reliable framework of criteria, which was missing until now, for evaluating the sustainability of nanoproducts. A literature review of the frameworks and tools employed to assess nanoproducts sustainability implications was firstly performed to select an initial set of criteria. A survey of experts in the sustainable nanotechnology domain was then conducted to elicit their knowledge in terms of completeness, reliability and validity of the criteria set. Ranking and correlation analyses completed the research by identifying the parameters of major interest as well as the links and dependencies between them. A total of 54 and 65 experts replied to the pilot and main survey, respectively. The reliability and validity of the criteria was assessed with the responses from both questionnaires, whereas the answers from the main survey were used to calculate the relative index of the criteria as well as their correlations. This research resulted in a framework composed of 68 criteria, which are structured into six main areas: (i) economic performance; (ii) environmental impacts, (iii) environmental risk assessment; (iv) human health risk assessment; (v) social implications and (vi) technical performance. This study helps to broaden the understanding on the identification of criteria for sustainability assessments. It also provides those interested in evaluating nanotechnology implications with the basis for real case studies, possibly by integrating available information with the stakeholders using tools that support decision-making. [ABSTRACT FROM AUTHOR]

Carbon fibre epoxy composites are sought after for their excellent specific energy absorption (SEA) but are costly. A range of prepreg carbon fibre epoxy layups were subjected to a 10 m/s impact with 4 kJ of energy. Fibre volume fraction and voidage were determined for each sample and the fracture analysed in detail. SEA ranged from 35.27 J/g to 60.25 J/g with the highest performance from 8 plies of 200 gsm 2 × 2 twill all laid at 0°. Vacuum assisted oven cure resulted in higher voidage than autoclave cure (2.52% versus 0.17%) but did not affect SEA. According to a ratio of performance to cost the highest rated samples were an 8 ply oven cure and a 3 ply autoclave cure specimen and there was little difference between them. This work has highlighted that there is enormous potential for cost reduction of prepreg carbon fibre epoxy energy absorption structures through the use of heavier areal weight fabrics and fewer plies as well as through the use of oven cured prepreg. [ABSTRACT FROM AUTHOR]

Abstract: Fibre reinforced composites have excellent specific properties and are widely sought after by engineers seeking to reduce mass. However, end of life disposal is a significant problem and so research into more sustainable natural fibre composites is extremely topical. This paper examines the applicability of natural fibre composites for high performance structural applications. Woven flax and regenerated cellulose (Cordenka) textiles were pre-impregnated with commercially available epoxy resins and consolidated into test laminates in an autoclave to determine their static (compressive, tensile, flexural) and dynamic (energy absorption) properties. The range of compressive strengths was 77.5–299.6MPa. Tensile strengths ranged from 63 to 92.6MPa and interlaminar shear strength (ILSS) from 10.7 to 23.3MPa. Specific energy absorption (SEA) varied between 21.2–34.2kJ/kg. Biotex flax combined with MTM49 resin matched the SEA of T300 carbon fibre using the same resin system and layup. This work has demonstrated that natural fibre composites have significant scope for use in structural applications but additional work is required on fibre to matrix bonding in order to maximise their properties whilst remaining an environmentally credible option. [Copyright &y& Elsevier]

Abstract: This paper compares the mechanical properties of virgin and recycled woven carbon fibre prepreg and goes on to assess the potential for recycled carbon fibre reinforced plastic (rCFRP) to be used in high performance energy absorption structures. Three sets of material were examined: fresh containing virgin fibres and resin, aged which was an out of life but otherwise identical roll and recycled which contained recycled fibre and new resin. The compressive strength and modulus of rCFRP were approximately 94% of the values for fresh material. This correlated directly with the results from impact testing where rCFRP conical impact structures were found to have a specific energy absorption of 32.7kJ/kg versus 34.8kJ/kg for fresh material. The tensile and flexural strength of rCFRP were 65% of the value for fresh material. Tensile and flexural moduli of rCFRP were within 90% of fresh material and ILSS of rCFRP was 75% that of fresh. Overall rCFRP has been proved to remain a highly satisfactory engineering material. This is a significant finding as it proves that carbon fibre can be recycled and reused in high performance applications. This has significant implications for use of carbon fibre in the automotive industry where End of Life Vehicle (ELV) legislation requires 85% of materials to be recyclable. This work opens the door to significantly expanded use of carbon fibre in the automotive industry. Of equal significance is the finding that the mechanical properties of fresh and aged carbon fibre were all within ±6% of one another. This highlights an opportunity to understand resin system life in more detail in order to prevent the creation of composite waste at source. [Copyright &y& Elsevier]

Abstract: Natural fibre composites represent an environmentally sustainable alternative to conventional glass and carbon fibre composites. Fibres derived from plants are renewable and have low levels of embodied energy compared to synthetic fibres. They are also low cost, low density, have high specific properties, are non-abrasive and less harmful during handling. In motorsport the front and rear impact structures are required to act as both load-bearing members and energy absorption devices. The requirement to absorb large amounts of energy means that the specific energy absorption (SEA) of the material is critical to maintaining a low mass. This work focuses on the potential for natural fibres to replace synthetic fibres for future environmentally friendly energy absorption structures. Conical test specimens of jute, flax and hemp were manufactured using vacuum assisted resin transfer moulding (VARTM) and subjected to impact testing. The natural fibre cones exhibited high values of SEA: unwoven hemp 54.3J/g, woven flax 48.5J/g and woven jute 32.6J/g. The SEA was influenced primarily by fibre volume fraction (Vf) where a high Vf leads to high SEA. Significant variability in SEA resulted from the variation in fibre strength and Vf as a result of the VARTM manufacturing process. Natural fibre composites have the potential to be widely applied as low cost, sustainable energy absorption structures. [Copyright &y& Elsevier]

Abstract: This study was designed to ascertain if the addition of lignin to hemp-epoxy composites was beneficial to their mechanical properties. Composites were made using a VARTM method with a two-part epoxy resin and a non-woven hemp fibre mat. Lignin was added to the resin before infusion at concentrations varying between 0 and 10% w/w. Samples were then tested according to the relevant ISO standards. There was an increase in impact properties of the fabricated composites with the energy absorbed by the composite containing 5% w/w lignin being 145% higher than the composite with no lignin added. Both flexural and tensile modulus showed an increase when lignin was added up to 2.5% w/w, although there was a drop in both when the lignin was increased to 5% w/w, attributed to poor mixing and infusion due to the increased viscosity of the resin. In all cases, the addition of lignin increased the structural properties of the composites to some degree when compared with composites with no additional lignin. [Copyright &y& Elsevier]

Abstract: This paper examines the possibilities of using an established energy crop; Miscanthus giganteus as a filler/reinforcement in injection mouldable thermoplastic composites utilising a starch-based biopolymer; Novamont Mater-Bi as the matrix. A design of experiments methodology was used to reveal how varying the processing parameters and material formulation affected the impact performance of the biocomposite. The addition of Miscanthus fibres to the polymer results in composites with higher impact absorbance and loading than those of standard Mater-Bi. [Copyright &y& Elsevier]