1,721,015 research outputs found
Sustainable Order Quantity of Repairable Spare Parts
No full textIn the last few years companies and researchers have focused their attention on the sustainable issues of supply chain management. In spare parts (SPs) research, traditionally focused on inventory modeling, supply chain aspects have become of relevant interests. Many contributions could be found in scientific literature about logistics of spare parts, but there is a lack of attention on the sustainable issues. In this paper, authors give a contribution to the concept of sustainable management of spare parts, by defining a spare parts logistic model. The model considers the environmental impacts and benefits related to the possibility of repairing failed parts rather than purchasing new ones. It aims at identifying the optimal means of transport, as well as the optimal SP order quantity minimizing the global logistic costs function in which economic and environmental costs of both the options of repairing and purchasing SPs are considered. The capability of the model has been tested with reference to a numerical example based on real data of a leader manufacturer of bearings
Optimal dry port configuration for container terminals: A non-linear model for sustainable decision making
Full text linkIn recent years the maritime freight transport has rapidly increased, causing congestion in many port areas. In some cases, in order to improve the capacity and the reliability of the temporary storage, a solution, recommended by industry officials, is the expansion of the terminal capacity. When this solution is not available, the ‘dry port’ area represents an effective alternative. The adoption of a dry port, if on one hand leads to benefits on terminal congestion, on the other hand requires resources and investments due to the transport of the container from port to dry port and vice versa. In the evaluation of the strategy to be adopted different aspects shall be evaluated to estimate time required for the container handling inside and outside the terminal on the basis of the congestion degree. In this paper, to support decision makers in identifying the best strategy to be adopted, a mathematical model allowing to identify the number of containers to be stocked in port and/or in dry port is defined considering the intra-/inter-terminal handling of the containers, in order to minimize the overall running costs and of the carbon footprint. The model, based on a computational algorithm for non-linear programming, is able to provide the number of containers to be stocked in port and/or in dry port, ensuring an effective strategy dependent on ‘road’ and ‘non-road' material handling equipment adopted, on the number and size of containers, as well as on the distance from port to dry port. Results obtained from numerical experiments show that, on the basis of the running cost and the carbon footprint of the container handling activities, it is possible to identify the most economic and eco-friendly container handling configuration. The case study of the Port of Bari (Italy) is investigated. In this case, given the overall number of containers to be stocked and the distance between port and dry port, the solutions found by the model identify a configuration able to ensure a reduction of 7% and 11% of the running cost and of the carbon footprint, respectively, when compared to the configuration in which all containers are stored in the port
Waste collection with smart bins and residual capacity forecasting: The case of an Apulia Town
No full textIn most countries, Municipal solid waste (MSW) collection and disposal are among the major problems of the urban environment. To this concern, the Key Enabling Technologies of Industry 4.0 (I4.0) play a crucial role. The I4.0 brings the new industrial paradigm in the smart cities, with strong cooperation of the digital and physical worlds through the cyber-physical systems. In particular, the intelligent bins (so-called smart bins) allow monitoring and provide real-time information on their capacity use. If, on the one hand, the MSW collection process is a topic widely investigated in the scientific literature, on the other hand, the studies on the adoption of the smart bins in MSW collection aren't that widespread. A technical-economic assessment of the implementation of the MSW collection based on the dynamic vehicle routing led by smart bins for a southern Italian town is proposed in the present work. The study evaluates the impact on the MSW collection considering the changes in terms of frequency of bins collected and dynamic vehicle routing, given by the residual capacity data provided from smart bins. To this concern, the costs and the emission due to MSW collection are minimized conducting a scenario analysis finalized to identify the proper service level to the citizenship, under municipal regulations, forecasting the residual capacity of each smart bin. Results of the case study showed that the adoption of the smart bins leads to significant benefits in both economic and environmental terms, providing proper service level for citizens
Modelling the 2D object recognition task in manufacturing context: An information-based model
No full textIn the last decays, manufacturing systems evolved to meet the high product variety required by the market. Different products can be manufactured in the mixed-model assembly lines, with an increase in the process complexity. In these production systems, the required flexibility is mainly provided by operators in the final assembly stages. Here, human errors could lead to high economic losses. A lack is observed in available research concerning a formal quantification of manufacturing complexity considering the joint effect of shape complexity and similarity in the mix variety. This paper focuses on operator decision-making in 2D object recognition tasks, since this is the most critical task performed in mixed model assembly systems. A novel model to quantify the information content in 2D object recognition task is proposed. The model is based on the Shannon's Entropy theory and considers both shape complexity and object similarities. Numerical experiments are provided, and results obtained show the effectiveness of the model in capturing the joint effect of shape complexity and similarities on the task information content. The proposed model can be adopted in a production environment for re-allocating tasks/sub-tasks to avoid the high amount of information to be processed affecting operators' performance
SIMULATING PERT-PATH NETWORKS FOR SOLVING A RESOURCE ALLOCATION PROBLEM IN PROJECT-TYPE SYSTEMS
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Minimum Emissions Configuration of a Green Energy–Steel System: An Analytical Model
Full text linkThe need to significantly reduce emissions from the steelmaking sector requires effective and ready-to-use technical solutions. With this aim, different decarbonization strategies have been investigated by both researchers and practitioners. To this concern, the most promising pathway is represented by the replacement of natural gas with pure hydrogen in the direct reduced iron (DRI) production process to feed an electric arc furnace (EAF). This solution allows to significantly reduce direct emissions of carbon dioxide from the DRI process but requires a significant amount of electricity to power electrolyzers adopted to produce hydrogen. The adoption of renewable electricity sources (green hydrogen) would reduce emissions by 95–100% compared to the blast furnace–basic oxygen furnace (BF–BOF) route. In this work, an analytical model for the identification of the minimum emission configuration of a green energy–steel system consisting of a secondary route supported by a DRI production process and a renewable energy conversion system is proposed. In the model, both technological features of the hydrogen steel plant and renewable energy production potential of the site where it is to be located are considered. Compared to previous studies, the novelty of this work consists of the joint modeling of a renewable energy system and a steel plant. This allows to optimize the overall system from an environmental point of view, considering the availability of green hydrogen as an inherent part of the model. Numerical experiments proved the effectiveness of the model proposed in evaluating the suitability of using green hydrogen in the steelmaking process. Depending on the characteristics of the site and the renewable energy conversion system adopted, decreases in emissions ranging from 60% to 91%, compared to the BF–BOF route, were observed for the green energy–steel system considered It was found that the environmental benefit of using hydrogen in the secondary route is strictly related to the national energy mix and to the electrolyzers’ technology. Depending on the reference context, it was found that there exists a maximum value of the emission factor from the national electricity grid below which is environmentally convenient to produce DRI by using only hydrogen. It was moreover found that the lower the electricity consumption of the electrolyzer, the higher the value assumed by the emission factor from the electricity grid, which makes the use of hydrogen convenient
A carbon footprint calculator for the municipal waste collection system of Bari
No full textThe concept of smart city is being receiving wide consideration as a guiding principle of European public policy. Providing "smartness" to modern society is emerging as a strategy to coordinate sets of interventions aiming at make city more sustainable. Following the principle that what is not measured cannot be managed, the authors propose a Carbon Footprint Calculator (CFC) to evaluate and monitor emissions resulting from the collection of municipal solid waste system. This user-friendly tool has been developed in the frame of European project "RES NOVAE" with the aim of providing the city with a 'smart governance'. Smart governance is a cornerstone of smart city: it means stakeholders cooperating in decision making process and public or social service. Indeed, the calculator is suitable for both public decision makers and citizens. Policy maker can use the CFC proposed to support greenhouse gases monitoring as well as to provide an estimation of a potential change in emissions associated with management and technological changes in waste collection. 'Smart' citizens will use the carbon footprint calculator to glean consciousness about personal behaviours affecting green house gas emissions. The tool stands as a formative instrument to involve citizens in societal challenges and increase their public participation
Economic and environmental savings from upgraded biogas applications
No full textThe directive 2009/28 CE state a mandatory 10% minimum target to be achieved by all member states for the share of biofuels in transport petrol and diesel consumption by 2020. In the Directive, the advantage, in terms of greenhouse gas (GHG) saving, of agricultural manure and municipal organic waste treatments for biogas production is highlighted. Key biogas applications are identified in both direct energy conversion (combined heat and power-CHP) and in its use as biomethane (biogas upgrading). In the attempt to achieve EU targets, Italian incentive policies are moving from generation-based incentive (GBI) towards premium for reducing GHG emissions from power plant. In this context, the evaluation of biogas applications feasibility, from both an economic and an environmental point of view, is required. In this paper economic and environmental savings obtainable from both direct biogas application (CHP) and upgraded biogas applications (in-grid feeding or traditional petroleum based fuel replacement) are compared. Municipal organic wastes as substrate for biogas production have been considered. Economic and environmental performances of different scenarios are evaluated. Scenarios differ for biogas treatments and final applications. In all scenarios, emission savings have been calculated by means of an LCA approach. In case of CHP application, GHG emissions are compared with those corresponding to the national fuel mix used to generate electricity. In case of in-grid feeding of upgraded biogas (biomethane), GHG from biomethane production are compared with emissions from extraction, production and transportation of natural gas. Concerning fuel replacement application, Well To Tank (WTT) and Tank to Wheels (TTW) approaches are implemented in order to evaluate the Well To Wheels (WTW) environmental performance of the scenario considered. The purpose of this research is twofold: on one hand, to compare benefits in terms of GHG and local (NOx, PM, CO) emissions achievable of biogas/biomethane applications; on the other hand, to identify effective incentive policies allowing to give economic feasibility to biogas/biomethane applications
Investigating the circular economy’s rebound effect in manufacturing: a systematic literature review
No full textCircular economy (CE) is a model of production and consumption for closing material loops, based on the implementation of different circular strategies (e.g., refuse, reduce, reuse and recycle). This paradigm relies on the maximization of the value of resources in use by minimizing negative environmental impacts as well as social and economic ones. As matter of fact, CE is widespread in manufacturing firms to reduce both the consumption of virgin materials and energy and the production of waste along the whole value chain to achieve sustainability. Nevertheless, the implementation of the CE paradigm is hampered by multiple and heterogeneous barriers and sometimes leads to the socalled rebound effect (defined in the energy research domain as resources overuse due to an improved efficiency of a system). To this concern, this paper presents a systematic literature review to explore how in the manufacturing industry the research context of CE is related to the rebound effect. First, it provides the domains, boundaries and open issues to better understand the link between the two topics. Second, it contributes to show the principals enablers and potential business models to manage the CE’s rebound effect. Lastly, it offers a schematic organization of the large number of studies extant in the research domain explored, to provide guidelines to policymakers, managers and consumers in coping with the rebound effect of CE, and to define a baseline for future research
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