322,886 research outputs found

    Reuse scenarios of tires textile fibers: an environmental evaluation

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    Abstract End of Life Tires (ELT) constitute a major portion of End of life Vehicles (ELV). The treatment process of ELTs is primarily aimed at recovering steel and rubber, which jointly represent the main portion of the ELT material and are currently applied in different sectors. During the treatment of ELTs, other sub-products are generated in significant quantities (about 10-15% in weight), as textile fibers that currently are landfilled or used for energy recovery. The aim of this study is a comparative evaluation of the environmental impacts related to three different end of life scenarios for the textile fibers. In addition to landfilling and incineration, this study considers the possibility to reuse textile fibers as reinforcement in bituminous conglomerates. Results obtained through the Life Cycle Assessment study confirms that the reuse scenario leads to a relevant reduction of impacts in terms of Global Warming Potential. However, by considering other environmental metrics the reuse scenario is not always the less impactful one

    Achieving a holistic view of the life cycle performance of existing dwellings

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    Models which fully evaluate the life cycle energy and greenhouse gas (GHG) emissions of national housing stocks are not reported in literature. Capturing a holistic view of energy and emissions of the residential sector is an important process that can lead to a more effective policy making. This paper presents a methodology which evaluates the life cycle energy and GHG emissions of retrofitting housing stocks considering all life cycle stages and incorporating, to the greatest extent possible, all upstream inputs. To achieve this, we developed a hybrid model of the existing Irish housing stock, comprising a process-based approach supplemented by input-output LCA for installation of materials and fit-outs and maintenance of appliances. Life cycle analysis (LCA) is a commonly accepted technique for evaluating cradle-to-grave environmental impacts of a product. Using an assumed 50-year life span in all cases, representative archetypes were used to estimate the performance along retro fitting, operation, maintenance and disassembly phases of the three selected house retrofit scenarios: BaseCase (no interven- tion), Current Standards (retrofitting to meet current building regulations) and Passive House (retrofitting to meet Passive House Standards). Results show that detached houses displayed the highest range of life cycle energy and exhibited the greatest absolute and percentage reductions compared to other house types, as life cycle energy ranges from 386-614 kWh/m2yr, 225-261 kWh/m2yr and 126-137 kWh/m2yr for all house scenarios, respectively. Using these results an assessment is provided for policy makers on a holistic view of the life cycle performance of existing dwellings

    A culturally-focused life cycle sustainability assessment: Analysis of forestry value chain options with Māori land owners : A thesis presented in partial fulfilment of the requirements of Doctor of Philosophy in Life Cycle Management At Massey University, Palmerston North, New Zealand

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    The purpose of this research was to 1) explore the potential for the more distinctive representation of Māori culture in Life Cycle Sustainability Assessment (LCSA), and 2) understand the relationship between culturally-focused LCSA and the Māori decisionmaking process. These two interrelated aspects were investigated through participatory engagement with three members of the Ngāti Porou iwi (tribe), and through collaborative development of three forestry LCSA scenarios (radiata pine, rimu, and mānuka). Aligning with principles of kaupapa Māori research, a participatory LCSA methodology approach was created which encapsulated five phases: 1) understand Ngāti Porou aspirations and concerns, 2) co-develop options for forestry scenarios, 3) co-develop and select LCSA indicators (including a cultural indicator), 4) LCSA indicator data collection and modelling, and 5) communication of results. The methodology utilised a mixed methods approach as Stage 1, 2, 3, and 5 are predominantly qualitative while Stage 4 is predominantly quantitative. Culture was represented in the participatory LCSA in two ways. Firstly, a bespoke cultural indicator (Cultural Indicator Matrix) was co-developed to distinctly include culture within LCSA. The Cultural Indicator Matrix was based on and adapted an existing cultural decision-making framework (i.e. the Mauri Model) in order to ensure its capability to represent both Ngāti Porou aspirations and the forestry value chains explored in this research. The Cultural Indicator Matrix was completed by each participant and subjectively measured the impact they perceived each forestry process or product had upon a range of Ngāti Porou aspirations. Secondly, a participatory research approach was utilised that itself made the LCSA process more culturally-focused. The participatory approach relied on active engagement with the research participants throughout the LCSA study, primarily with the utilisation of semi-structured interviews. Such collaborative participatory engagement with the research participants allowed for their cultural input, preferences, and knowledge at each stage of the LCSA process. This research has yielded several original and meaningful results: 1. The Cultural Indicator Matrix is a new culturally-focused mechanism which can be used to support the Māori decision-making process. The participants viewed the Cultural Indicator Matrix as an effective method for gathering community impressions of how potential forestry life cycle processes could impact upon their cultural aspirations. 2. The participants felt the participatory LCSA aspect was crucially important; the open and consistent communication between themselves and the LCSA practitioner provided them with more control, access to information, understanding of the LCSA process, and enhanced their acceptance of the final results. They considered that the results of the culturally-focused LCSA gave them “validation” and “direction”, and justified their interests in pursuing forestry options for their land. 3. The participatory LCSA process led to the identification of a need to formally include a Cultural Compliance process with the LCSA. The Cultural Compliance process is comprised of six cultural components occurring throughout the forestry life cycle. Recognition of these components helps to ensure that appropriate and necessary cultural considerations are taken into account during relevant forestry life cycle processes. It is unlikely that this insight would have been reached if not for the participatory engagement focus of this LCSA research. 4. The development and analysis of three forestry scenarios using a range of sustainability indicators generated distinctive datasets on the life cycles of radiata pine, rimu, and mānuka. As the rimu and mānuka scenarios are particularly underrepresented in forestry-life cycle literature, this research has provided a contribution to knowledge regarding these two forestry options. For the first time, indigenous culture has been represented alongside economic, social, and environmental impacts in LCSA. This comprehensive presentation of results facilitates the decision-making process by providing the decision maker(s) with information about the “big picture”, thus supporting educated and informed decisions. Furthermore, a culturally-focused LCSA approach helps to ensure that culture is not lost during the decision-making process, but rather is an active component. Finally, of critical importance, both the culturally-focused LCSA process and associated results will further enable the recognition cultural groups, including their values and aspirations. The explicit acknowledgement of culture in LCSA will engender more awareness and protection for culture, lessen the isolation and marginalisation of culture, and empower cultural groups to develop and pursue brave choices

    Detection of advanced persistent threat using machine-learning correlation analysis

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    As one of the most serious types of cyber attack, Advanced Persistent Threats (APT) have caused major concerns on a global scale. APT refers to a persistent, multi-stage attack with the intention to compromise the system and gain information from the targeted system, which has the potential to cause significant damage and substantial financial loss. The accurate detection and prediction of APT is an ongoing challenge. This work proposes a novel machine learning-based system entitled MLAPT, which can accurately and rapidly detect and predict APT attacks in a systematic way. The MLAPT runs through three main phases: (1) Threat detection, in which eight methods have been developed to detect different techniques used during the various APT steps. The implementation and validation of these methods with real traffic is a significant contribution to the current body of research; (2) Alert correlation, in which a correlation framework is designed to link the outputs of the detection methods, aims to identify alerts that could be related and belong to a single APT scenario; and (3) Attack prediction, in which a machine learning-based prediction module is proposed based on the correlation framework output, to be used by the network security team to determine the probability of the early alerts to develop a complete APT attack. MLAPT is experimentally evaluated and the presented sy

    Life cycle assessment of completely recyclable concrete

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    Since the construction sector uses 50% of the Earth. s raw materials and produces 50% of its waste, the development of more durable and sustainable building materials is crucial. Today, Construction and Demolition Waste (CDW) is mainly used in low level applications, namely as unbound material for foundations, e.g., in road construction. Mineral demolition waste can be recycled as crushed aggregates for concrete, but these reduce the compressive strength and affect the workability due to higher values of water absorption. To advance the use of concrete rubble, Completely Recyclable Concrete (CRC) is designed for reincarnation within the cement production, following the Cradle-to-Cradle (C2C) principle. By the design, CRC becomes a resource for cement production because the chemical composition of CRC will be similar to that of cement raw materials. If CRC is used on a regular basis, a closed concrete-cement-concrete material cycle will arise, which is completely different from the current life cycle of traditional concrete. Within the research towards this CRC it is important to quantify the benefit for the environment and Life Cycle Assessment (LCA) needs to be performed, of which the results are presented in a this paper. It was observed that CRC could significantly reduce the global warming potential of concrete

    Life cycle assessment of biofuels from Jatropha curcas in West Africa: a field study

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    In recent years, liquid biofuels for transport have benefited from significant political support due to their potential role in curbing climate change and reducing our dependence on fossil fuels. They may also participate to rural development by providing new markets for agricultural production. However, the growth of energy crops has raised concerns due to their high consumption of conventional fuels, fertilizers and pesticides, their impacts on ecosystems and their competition for arable land with food crops. Lowinput species such as Jatropha curcas, a perennial, inedible crop well adapted to semiarid regions, has received much interest as a new alternative for biofuel production, minimizing adverse effects on the environment and food supply. Here, we used life-cycle assessment to quantify the benefits of J. curcas biofuel production inWest Africa in terms of greenhouse gas emissions and fossil energy use, compared with fossil diesel fuel and other biofuels. Biodiesel from J. curcas has a much higher performance than current biofuels, relative to oil-derived diesel fuels. Under West Africa conditions, J. curcas biodiesel allows a 72% saving in greenhouse gas emissions compared with conventional diesel fuel, and its energy yield (the ratio of biodiesel energy output to fossil energy input) is 4.7. J. curcas production studied is eco-compatible for the impacts under consideration and fits into the context of sustainable development

    Techno-economic and greenhouse gas savings assessment of decentralized biomass gasification for electrifying the rural areas of Indonesia

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    This study explored the feasibility of decentralized gasification of oil palm biomass in Indonesia to relieve its over-dependence on fossil fuel-based power generation and facilitate the electrification of its rural areas. The techno-feasibility of the gasification of oil palm biomass was first evaluated by reviewing existing literature. Subsequently, two scenarios (V1 and V2, and M1 and M2) were proposed regarding the use cases of the village and mill, respectively. The capacity of the gasification systems in the V1 and M1 scenarios are determined by the total amount of oil palm biomass available in the village and mill, respectively. The capacity of the gasification systems in the V2 and M2 scenarios is determined by the respective electricity demand of the village and mill. The global warming impact and economic feasibility (net present value (NPV) and levelized cost of electricity (LCOE)) of the proposed systems were compared with that of the current practices (diesel generator for the village use case and biomass boiler combustion for the mill use case) using life cycle assessment (LCA) and cost-benefit analysis (CBA). Under the current daily demand per household (0.4 kWh), deploying the V2 system in 104 villages with 500 households each could save up to 17.9 thousand tons of CO2-eq per year compared to the current diesel-based practice. If the electricity could be fed into the national grid, the M1 system with 100% capacity factor could provide yearly GHG emissions mitigation of 5.8 × 104 ton CO2-eq, relative to the current boiler combustion-based reference scenario. M1 had a positive mean NPV if the electricity could be fed into the national grid, while M2 had a positive mean NPV at the biochar price of 500 USD/ton. Under the current electricity tariff (ET) (0.11 kWh) and the biochar price of 2650 USD/ton, daily household demands of 2 and 1.8 kWh were required to reach the break-even point of the mean NPV for the V2 system for the cases of 300 and 500 households, respectively. The average LCOE of V2 is approximately one-fourth that of the reference scenario, while the average LCOE of V1 is larger than that of the reference scenario. The average LCOE of M1 decreased to around 0.06 USD/kWh for the case of a 100% capacity factor. Sensitivity analysis showed that the capital cost of gasification system and its overall electrical efficiency had the most significant effects on the NPV. Finally, practical system deployment was discussed, with consideration of policy formulation and fiscal incentives

    Modelling Private Wealth Accumulation and Spend-down in the Italian Microsimulation Model CAPP_DYN: A Life-Cycle Approach

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    In microsimulation literature a limited number of models include a module aimed at analyzing and projecting the evolution of privat e wealth over time. However, this issue appears crucial in order to comprehensively evaluate the li kely distributional effects of institutional reforms adopted to cope with population ageing. In this work we describe the implementation in the Italian dynamic micro simulation model CAPP_DYN of a new module in which households\u2019 savings and asset allocation are modelled. In parti cular, we aim to account for possible behavioural responses to pension reforms in househo ld savings. To this end, we rely on an approximate life cycle structural framework for est imating saving behaviour, while adopting a traditional stochastic micro simulation approach fo r asset allocation. In line with Ando and Nicoletti Altimari (2004), we emphasize the role of lifetime economic resources in households\u2019 consumption decisions, yet we further account for i nternal habit formation and subjective expectations on pension outcomes in the econometric stage. In addition, we model intergenerational transfers of private wealth in a probabilistic fashio

    Integration of end-of-life options as a design criterion in methods and tools for ecodesign

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    Ecodesigning a product consists (amongst other things) in assessing what its environmental impacts will be throughout its life (that is to say from its design phase to its end of life), in order to limit them. Some tools and methods exist to (eco)design a product, just like methods that assess its environmental impacts (more often, a posteriori). But it is now well accepted that these are the early design decisions that will initiate the greatest consequences on the product’s end-of-life options and their impacts. Thus, the present work aims at analysing traditional design tools, so as to integrate end-of-life possibilities in the form of recommendations for the design step. This proposal will be illustrated by means of a wind turbine design.EcoSD networ
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