Life Cycle Scenario Research Articles

Rehabilitation or Demolition of Small Hydropower Plants: Evaluation of the Environmental and Economic Sustainability of the Case Study “El Cerrajón”

During the 1950s, numerous small-capacity hydroelectric power plants were built in Spain. Seventy-five years on, it must now be decided whether to continue their operation or demolish them. In order to provide a valid answer, it is necessary to have access to decision-making tools that enable sustainable economic and environmental decision making. The present work proposes a methodology that employs an economic indicator of life cycle cost and environmental indicators of carbon footprint and embodied energy by means of life cycle data analysis. Quantification of the impacts was carried out with the support of construction cost databases and the PREDICE software tool for the quantification of environmental impacts incorporated into maintenance tasks. The case study of the “Cerrajón” power plant was analyzed, where historical hydrological cycles were considered. A life cycle scenario was evaluated in which renovation extended the life of the power plant by a further 75 years. The results show savings in environmental impacts with respect to the impacts of the Spanish energy mix of up to 175 kgCO2 per MWh produced, although no economic benefit was found. It was also shown that in climate change scenarios, the profit price breakeven increases. Rehabilitation appears to present the best choice when combining the two criteria.

Unraveling the climate neutrality of wood derivatives and biopolymers

This work compares fossil-based polymers to wood derivatives and polylactic acid using a lifecycle scenario analysis. The aim is to unravel the climate neutrality and advantages of bio-based polymers like wood derivatives.

DURABOT: THE TOOL TO INTRODUCE DURABILITY IN THE DESIGN PROCESS

AbstractThe extension of the product lifecycle is crucial in the application of Circular Economy principles. However, when Energy Related Products are concerned, managing a durable product does not necessarily mean dealing with sustainable products. This happens because components and/or materials are affected by aging and lead to increased requirement of resources to run (i.e. electricity); there are certain trends that, although distinct from the previous facts, balance the effects of aging, i.e. energy grid mix decarbonization. In the present work an approach that considers both the economic and environmental consequences of durable products is proposed. The Durabot tool has been developed to accomplish the environmental analysis. The work overcomes the main literature criticalities: enables the assessment of environmental consequences of durability ; the evolution of energy grid mix is introduced; the environmental consequences of durable products in different lifecycle scenarios can be assessed during the design phase; therefore, the components to substitute and to make accessible are identified. The tool is intended to be used aiming at design for product lifecycle extension, maintaining both economic and environmental convenience

Estimation of global waste smartphones and embedded critical raw materials: An industry life cycle perspective

Considering the quarterly fluctuation characteristics of global smartphone shipment, a novel and improved Verhulst model was proposed for forecasting smartphone shipments under different industry life cycle scenarios. The number of waste smartphones between 2007 and 2039 was estimated via using the lifespan distribution of electronics. The weight of the disposals was then converted by using product data collected from 2766 sampled smartphone devices. It was found that under the scenario of maturity, approximately 126,000 tons critical raw materials (CRMs) were expected to be recovered by 2039. According to the CRMs lists published by China and the European Union, the recoverable amount compared to about 62,000 tons and 64,000 tons, respectively. Enhancing the recycling of waste smartphones worldwide, will provide a new option to ensure an important part of the stability of the CRMs supply chains.

Sustainability Evaluation of a Concrete Gravity Dam: Life Cycle Assessment, Carbon Footprint Analysis, and Life Cycle Costing

Exploring the life cycle of infrastructures, like dams, is important for decision-makers since it allows for evaluating its overall sustainability, and identifying ways to balance the benefits and costs of dam development. In this study, the life cycle assessment (LCA) of the existing concrete gravity Pine Flat dam in the stages of construction to destruction, disposal, and recycling is investigated through ReCiPe 2016 methodology and the effect of two approaches of seismic retrofitting and non-retrofitting in the life cycle of the dam is studied. For a comprehensive understanding of the sustainability of the dam's life cycle, carbon footprint analysis (CFA) and life cycle costing (LCC) are also conducted to identify the main sources of greenhouse gas (GHG) emissions and evaluate the economic performance. These demands begin by assessing the dam’s life cycle across three distinct stages, namely, initial construction, seismic retrofitting, and decommissioning, assuming recycling 20% of demolished concrete for the last stage. The outcomes of the evaluation are then presented for four different life cycle scenarios. The findings have underscored the importance of reducing air pollution and emphasize that human health is the most significant environmental concern as compared to the ecosystem and resource indicators. The concrete recycling considered during the decommissioning stage led to a 32% reduction in pollution caused by the dam disposal process. Additionally, the effect of retrofitting dams in decreasing environmental impact indicators such as carbon footprint and human health has been considered when compared to dam disposal. The economic and environmental costs of retrofitting Pine Flat dam were obtained about half of the equivalent expenses for its disposal and recycling stage.

CORPORATE STRATEGY FOR MANAGING EVOLUTIONARY PROCESSES OF THE ENTERPRISE DEVELOPMENT

The method for analyzing phase portraits of bifurcation diagrams of enterprise life cycle scenario models using IT pattern recognition has been proposed, which allowed to numerically determine the geometric parameters of the spatial forms that form the surfaces of phase portraits, and their size, corresponding to the loci of stability and interaction of four populations in a network of trophic relations. To analyze the results of the recognition of phase portraits of ELC bifurcation diagrams, singular points of perturbation, attenuation, cycles, equilibrium, their stability, the input examples of the state of bifurcation have been classified into five separate clusters in accordance with the ELC development scenarios. An IT support algorithm for the corporate strategy for managing the evolutionary processes of enterprise development has been developed. It covers the following stages: analysis and evaluation of the internal and external environment of the enterprise population and trophic relations; identification of possible motives for changing trophic relations and causes of synergy; studies of the nonlinear dynamics of ELC model scenarios; analysis of many strategic alternatives; selection of a strategy and preparation of a strategic plan; monitoring the results of achieving a synergistic effect, which will allow choosing strategies depending on the ELC stages and ensuring the competitiveness of the enterprise.

Life cycle greenhouse gas emissions of hemp-lime concrete wall constructions in Serbia: The impact of carbon sequestration, transport, waste production and end of life biogenic carbon emission

The construction industry contributes to climate change through significant greenhouse gas emissions. Utilising sustainable building materials with low embodied environmental impacts and low greenhouse gas emissions is key to future sustainable development. Bio-based materials, such as hemp-lime concrete, possess environmental advantages as they make use of a renewable raw material and can sequester CO2 from the atmosphere. Through the use of life cycle assessment methodology the study analyses the greenhouse gas emissions associated with the life cycle of a hemp-lime concrete wall and examines the effects of variations that can arise during the life cycle of the material. Sensitivity analyses were used to examine the effects of varying the hemp shiv sequestration factor, binder carbonation factor, gate to site transport distances and raw material construction waste on greenhouse gas emissions, culminating in the creation of three primary emission scenarios (average, pessimistic and optimistic). It was found that the examined variables can have a large impact on greenhouse gas emissions and the environmental perception of the material, as the optimistic life cycle scenario had a negative global warming potential (−9.696kgCO2eq.), while the pessimistic scenario had a positive global warming potential (10.165kgCO2eq.). Additionally alternative end of life scenarios were developed to examine the effects of varying hemp shiv degradability at the end of life stage, demonstrating the potentially large impacts a high factor of degradable organic carbon can have on life cycle greenhouse gas emissions.

MODEL FOR CALCULATING THE COSTS OF A BUG BOUNTY PROGRAM FOR TESTING SECURITY VULNERABILITIES

The article describes the ways of researching bug bounties of programs and proposes a new approach for calculating the score of the found vulnerabilities. The paper begins with an introduction to the understanding of vulnerability management processes and the concept of an attack surface. The paper analyzes the statistics of all vulnerabilities found in information systems over the past ten years, which are divided according to the standard CVSS score. The types and vectors of attacks are analyzed in the example of the financial sector. Additionally, hacking and incidents are categorized by attack vectors in the financial sector. The following is the ratio of the most popular types and vectors of attacks to the criticality of information systems. A rating of critical and high vulnerabilities of one of the bug bounty platforms is presented with a detailed description of the types of attacks and exploitation techniques. An integral part of the vulnerability management process is the categorization of importance and impact on the organization. Possible life cycle scenarios for the identified vulnerability in an information system are also presented through the eyes of the owner of the vulnerability information and the owner of such an information system. A comparative quantitative and qualitative analysis of the maturity of bug bounty programs from the moment of launch and over the years, as well as the factors influencing the maturity of the program, are carried out. The statistics of vulnerabilities found in public bug bounty programs over the past six years are analyzed. The author proposes her approach to calculating the effective cost of a bug bounty program and conducts an experimental test on three programs. The factors influencing the calculation of the effective cost of vulnerabilities are highlighted. Approaches to vulnerability assessment and validation by bug bounty platforms and the stages of arbitration between the owner of the information system and the vulnerability researcher are considered. The study concludes with recommendations for achieving a higher level of maturity in vulnerability management processes. The forging highlights the continuity of the emergence and disappearance of additional factors in vulnerability management processes, in which bug bounty programs are an integral part. The interdependence of the maturity of the company’s processes and its bug bounty program requires the attraction of sufficient resources for its effectiveness.

Process Simulation Integrated Life Cycle Net Energy Analysis and GHG Assessment of Fuel-Grade Bioethanol Production from Unutilized Rice Straw

For the life cycle scenario of bioethanol production from unutilized rice straw, the life cycle stage of paddy rice cultivation can be excluded with a zero-inventory allocation rule, i.e., rice straw with no applied valorization in current practice. This study evaluates the life cycle net energy analysis and greenhouse gas (GHG) assessment for a scaled-up bioethanol production plant using unutilized rice straw as the feedstock. The process simulation technique is integrated to model a scaled-up production plant to produce bioethanol at 99.7 vol% purity from unutilized rice straw, and the simulation results are retrieved to calculate inventory data for the life cycle assessment (LCA). The simulated mass flow and energy flow results are comparable with that of real plants, reported in the published literature, which validates the process simulations in this study. Including energy generation using waste flows in the process (i.e., wastewater and solid residues), the life cycle net energy analysis results show a net energy gain of 7804.0 MJ/m3 of bioethanol with a net renewable energy gain of 38230.9 MJ/m3 of bioethanol that corresponds to a net energy ratio of 1.20 and renewability factor of 5.49. The life cycle GHG assessment exhibits a net global warming potential of 584.8 kg CO2 eq/m3 of bioethanol. The effect of system boundary expansion up to the end-of-life stage as gasohol (E10), the sensitivity of the key process parameters, and the economic benefit via valorization of unutilized rice straw are further analyzed and discussed.

Mechanical Upcycling Immiscible Polyethylene Terephthalate-Polypropylene Blends with Carbon Fiber Reinforcement.

Ineffective sorting of post-consumer plastics remains one of the major obstacles in the recycling of plastics. Consequently, these highly heterogeneous, mixed post-consumer plastics will end up in landfill or have to be incinerated as repurposing them directly would lead to a polymer blend with inferior quality for many end-uses. In this work, we demonstrate the use of carbon fibers (CFs) to practically upgrade the mechanical properties of mixed plastics, adding value to them. This will create a stronger demand for mixed plastics to be used in various engineering applications. Using polyethylene terephthalate (PET) and polypropylene (PP) as the model immiscible polymer blend, we showed that the incorporation of CFs increased the tensile, flexural, and single-edge notched fracture toughness of the resulting CF-reinforced PET/PP composite blends. Despite the high environmental burden associated with the production of CFs, cradle-to-grave life-cycle analysis showed that CF-reinforced PET/PP composites have a lower environmental impact than the life-cycle scenarios of “doing nothing” and repurposing immiscible PET/PP blends as it is without CF reinforcement. This can be attributed to the weight saving achieved, a direct result of their higher mechanical performance. Our work opens up opportunities for the use of mixed plastics in various higher value applications such that they can be diverted away from landfill or incineration, in line with the concept of circular economy.

Characterization of the state of health of a complex system at the end of use

The state of health (SoH) of an end-of-life product is one of the levers for optimizing the circular economy (CE) process in order to allow the product life-extension. Many approaches have been developed in the literature to estimate the SoH of a complex system (CS). In this study, we asked ourselves the following two questions: First, how to optimize the circular lifecycle scenarios of the components of a product at its end of life? And second, how to estimate the SoH of a product at the end of its life? To answer these questions, we proceeded as follows. First of all, the state of health of a product needs to be considered as an important parameter as well as performance or reliability. To estimate the SoH, it is necessary to identify the product parameters to be observed. The problem here is to choose the most relevant parameters among all those available for a CS. To do this, we have proposed a conditional-based maintenance approach (CBM) which consists in establishing the fault tree of a product. It consists of functionally breaking down a product into its various components and identifying the main failures for each of them. Then, these failures are used to identify the parameters to be monitored. Second, based on the most relevant parameters, the health indicators needed to estimate the SoH of the product are obtained. Then, the Prognostic and Health Management approach (PHM) is proposed in order to estimate the SoH. In the objective of providing a general solution that could be used for estimating the health status of any product, we have proposed a generic framework for the PHM approach. It serves as a guide in choosing the right approach according to the situation. Then, we proposed a decision-making strategy to optimize the process of orienting components in circular loops. This strategy is based only on the technical-functional indicator, which is the SoH of the components. Finally, we showed an example of the implementation of the proposed method for the case of the electrical scooter motor.

Designing Immortal Products: A Lifecycle Scenario-Based Approach

Immortal products are updated and upgraded to go from application to application and, in so doing, to extend their life as long as possible. Designing such products is the key to a sustainable society from the circular economy perspective. It is a new way of designing that must be supported by engineering tools to be deployed in companies, small and medium-sized enterprises (SMEs) included. The implementation of circular loops and the associated industrial systems are very dependent on the contexts and life scenarios of the products. Thus, depending on the products to be re-circulated, the processes controlled, and the actors involved, the requirements to be reported at design level are very diverse. This paper proposes a new design method based on lifecycle scenarios to be analyzed and designed. Supported by classical engineering tools that has been adapted for circular economy (CE) context, the lifecycle model enables simultaneous design of businesses, products and services and the evaluation of their environmental values. Three industrial design cases showing the application of engineering tools for implementation of CE lifecycle scenarios are presented.

A new approach of ecologically based life cycle assessment for biological wastewater treatments focused on energy recovery goals.

The energy potential of high-organic loaded agro-industrial effluents receiving biological treatment is often neglected, particularly in emergent regions, because of different technical and regulatory drawbacks. In addition, small alternative bioenergy sources are forced to compete disadvantageously with conventional energy supply, hindering their more extended exploitation. Thus, smart strategies to prove the environmental/economic potential of biogas and sludge produced in biological wastewater treatment systems (Bio-WWTs) are required to promote them as truly sustainable energy sources. In this view, the present study depicts a refined methodological framework for a more appropriate appraisal of Bio-WWTs promoting bioenergy recovery. Life cycle assessment (LCA) and emergy analysis (EmA) methods were merged around the statement of some identified and stated Principle-Criteria of Sustainability (PCS) for this kind of "water-energy nexus." As a result, a novel set of four single sustainability development indicators (SDIs) and one aggregated SDI were obtained to address sustainable conditions for valorization of bio-energy from agro-industrial Bio-WWTs. These indicators were made up of an environmental term coming from an LCA based on a system expansion approach as well as a second or "eco-economic" term obtained by means of EmA. This work introduces and shapes the "additionality" notion as an expression of overall sustainability and uses novel sustainability charts to interpret the obtained SDIs and their shifting or changes for different Bio-WWTs' life cycle scenarios. The "proof of concept" of this methodology is discussed along the obtained results for two case studies in Colombia.

Dynamic Lifecycle Cost Modeling for Adaptable Design Optimization of Additively Remanufactured Aeroengine Components

Additive manufacturing (AM) is being used increasingly for repair and remanufacturing of aeroengine components. This enables the consideration of a design margin approach to satisfy changing requirements, in which component lifespan can be optimized for different lifecycle scenarios. This paradigm requires lifecycle cost (LCC) modeling; however, the LCC models available in the literature consider mostly the manufacturing of a component, not its repair or remanufacturing. There is thus a need for an LCC model that can consider AM for repair/remanufacturing to quantify corresponding costs and benefits. This paper presents a dynamic LCC model that estimates cumulative costs over the in-service phase and a nested design optimization problem formulation that determines the optimal component lifespan range to minimize overall cost while maximizing performance. The developed methodology is demonstrated by means of an aeroengine turbine rear structure.

The Influence of Graphene Oxide on Nanoparticle Emissions during Drilling of Graphene/Epoxy Carbon-Fiber Reinforced Engineered Nanomaterials

Graphene oxide (GO) nanoparticles are increasingly being used to tailor industrial composites. However, despite the advantages, GO has shown conceivable health risks and toxicity to humans and the environment if released. This study investigates the influence that GO concentrations have on nanoparticle emissions from epoxy-reinforced carbon fiber hybrid composites (EP/CF) during a lifecycle scenario, that is, a drilling process. The mechanical properties are investigated and an automated drilling methodology in which the background noise is eliminated is used for the nanoparticle emissions measurements. Real-time measurements are collected using a condensation particle counter (CPC), a scanning mobility particle sizer spectrometer (SMPS), a real-time fast mobility particle spectrometer (DMS50) and post-test analytical methods. The results observe that all three nanoparticle reinforced samples demonstrated a statistically significant difference of up to a 243% increase in mean peak particle number concentration in comparison to the EP/CF sample. The results offer a novel set of data comparing the nanoparticle release of GO with varying filler weight concentration and correlating it the mechanical influence of the fillers. The results show that the release characteristics and the influence in particle number concentration are primarily dependent on the matrix brittleness and not necessarily the filler weight concentration within the nanocomposite.

Assessing public acceptance of the life cycle of CO2-based fuels: Does information make the difference?

Reducing the high CO 2 emissions from the transportation sector requires alternatives to current fossil-based power trains. One possible approach is the development of alternative fuels produced from CO 2 , water, and renewable energy. Besides technological feasibility of required process steps (CO 2 capture, CO 2 transport, fuel production infrastructure), a successful adoption requires acceptance of alternative CO 2 -based fuels and their infrastructure. This study focuses on public acceptance of CO 2 -based fuels' life cycle by laypeople (N = 325) using conjoint analysis. The laypeople evaluated life cycle scenarios consisting of diverse options regarding CO 2 capture, transport, and production infrastructure. To analyze the impact of information on acceptance evaluations, all respondents received information on energy efficiency and environmental impact of the process step options (2nd evaluation stage). The results revealed that CO 2 source and transport are most relevant for participants' decisions. Significant impacts of information were found: higher levels of information changed extremely the evaluation of the CO 2 capture options (e.g., air capture, chemical plant). The results highlight the importance of investigating laypeople's evaluations of life cycle scenarios, emphasize the relevance of providing adequate information to laypeople, and enable to derive information recommendations to reach a sustained public adoption of alternative fuels and their life cycle. • Laypeople's acceptance evaluation of the CO 2 -based fuel life cycle in conjoint study. • Higher acceptance for end products than for production steps of CO 2 -based fuels. • CO 2 capturing and transport represent the most acceptance-relevant process steps. • Preferred production scenarios vary widely between laymen and technical perspectives. • Information on environmental impact and energy demand change public preferences.

A decision support methodology for integrated machining process and operation plans for sustainability and productivity assessment

This paper presents a systematic methodology to enable environmental sustainability and productivity performance assessment for integrated process and operation plans at the machine cell level of a manufacturing system. This approach determines optimal process and operation plans from a range of possible alternatives that satisfy the objectives and constraints. The methodology provides a systematic procedure to highlight parameters that have significant impact on both sustainability and productivity performance metrics. We developed models and applied them to analyze manufacturing life cycle scenarios for collecting and categorizing key concepts towards building a material information model for sustainability. Integration of process and operation plans allows globalized assessment of sustainability and productivity, while development of a multi-criteria decision-making method leads to optimization of process planning activities based on the impact of conflicting sustainability and productivity metrics. A case study is detailed to demonstrate the sustainability-focused methodology, wherein integrated simulation and optimization techniques are used to support analysis of candidate scenarios and selection of preferred alternatives from a finite set of alternate process and operation plans. A discrete event simulation tool is used to model evolution of sustainability metrics (e.g., energy consumption) and productivity metrics (e.g., production time, cost) of a shop floor. The outcomes of this work include determination of optimized feature sequence plans which optimize various key performance indicators depending on stakeholder interest based on time, sustainability and production cost.

Environmental assessment of an animal fat based biodiesel: Defining goal, scope and life cycle inventory

Abstract The energy crisis and environmental problems have resulted in an increase of biofuels production. However, the production cost is the biggest commercialization drawback for fuels such as biodiesel; the highest cost in its production chain is associated with the raw material. Biodiesel is usually produced from vegetable oils; nevertheless, water supplies, fertilizers and large land areas are required for its production. An alternative is to use animal fat as the most economic raw material for biodiesel production. It does not compete with food safety and reduces the environmental impact caused by an inadequate disposal. But the use of biodiesel causes damages on some different parts of unmodified diesel engines and decrease their performance. Therefore, it is necessary to study additives that modify the thermodynamic and transport properties of biodiesel such as density, viscosity or surface tension. The aim of this research is to present the goal, scope and life cycle inventory necessary to evaluate the potential environmental impacts of ternary diesel + biodiesel + additives blends, as biofuels through life cycle assessment. Mass of reagents and blends components were identified, while they have already been tested and validated from the experimental data. The life cycle scenarios will include beef tallow, biodiesel, diesel and additives production, mixing processes, and blends combustion.

Addressing Circularity to Product Designers: Application to a Multi-Cell Power Electronics Converter

Abstract Design for enhancing a 4th industrial revolution thinking questions the sustainability of a massive use of IT devices. The communication between people and objects (IoT) inside and outside industries are supported by an increasing diversity of electronics using electric power. This causes irreversible damages on the ecosystems guarantying the livability of our planet. This paper therefore proposes a three stage method for product designers to design multiple-usage life cycle electronic products. The originality of the proposition stands in modeling the multiple-usage life cycle scenario to support the reparability of the electronic device based on a modular design of power converters. The method is applied on a power converter for photovoltaic panels. The paper concludes on the opportunity to merge technological innovations with a circular thinking in the early design stage of electronic based products. The multi-impact analysis and systemic vision as a basis of circular thinking and are a major challenge addressed to product designers in today’s 4.0 industries.

The use of recycled semiconductor material in crystalline silicon photovoltaic modules production - A life cycle assessment of environmental impacts

To offset the negative impact of photovoltaic modules on the environment, it is necessary to introduce a long-term strategy that includes a complete lifecycle assessment of all system components from the production phase through installation and operation to disposal. Recycling of waste products and worn-out systems is an important element of this strategy.As the conclusions from the previous studies have shown, thermal treatment provides an efficient first step in the recycling process, while chemical treatment was more advantageous in the second step.This study aims to assess the environmental impact of recovering and recycling the valuable semiconductor silicon wafer material from photovoltaic solar cells. A comparison was made between producing new solar cells with or without recycled silicon material.The analysis of the photovoltaic cell life cycle scenario including material recycling presented in this article was performed using SimaPro software and data combined and extended from different LCI databases. The idea is that the use of recycled materials, which were energy-consuming in the primary production stage, allows to meaningly reduce the energy input in the secondary life cycle.All stages of the silicon cell life cycle contribute to the Global Warming Potential (GWP) and greenhouse gas emissions reductions through the use of recycled silicon material represented 42%. The total environmental impact of photovoltaic production can be reduced by as much as 58%, mainly through reduced energy consumption in the production process of high purity crystalline silicon.