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• Companies implement continuous improvement (Lean Six Sigma) to increase efficiency. • LSS can compromise workers' health because increases physical and mental stress, if wrongly implemented. • LSS and Ergonomics complement each other and can have a synergistic effect. • There are no other scientific reviews about SS and Ergonomics until today. • The paper provides a scientific review to encourage and support future studies. Organisations seek to adopt strategies to increase their productivity and quality in highly competitive markets. For this purpose, Lean Six Sigma (LSS) is often used. It is frequently combined with other scientific areas such as Ergonomics. Integrating LSS and Ergonomics may improve productivity while preserving workers' health and safety. This study presents a systematic literature review to clarify the impacts of integrating LSS and Ergonomics on organisations. Also, it seeks to assess the main limitations while answering the defined research questions. The research was conducted in Scopus and Web of Science. From the 74 results, 16 articles were included based on the eligibility criteria. The results show that few scientific studies report the application of both areas. As for integrating LSS and Ergonomics, no pattern is observed in the methods and tools to be applied, highlighting that the most common were the DMAIC cycle and the Value Stream Mapping tool. Nevertheless, this review evidences many positive effects of this integration, both for organisations and workers. In general, the topic of this review has the potential to be further studied through conceptual studies and case studies in organisations from different sectors to provide broader conclusions and show the relevance of this theme. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the implications of the use of maritime pine non-debarked wood chips as an alternative solid fuel in industrial boilers in Portugal, highlighting the energy properties and chemical composition of the produced ash. Several samples are collected from different sources, on which a proximate analysis is carried out in order to determine the volatile matter content, fixed carbon content, ash content and higher heating value (HHV). The chemical composition of the ash samples is determined by the scanning electron microscope (SEM) method. Then, empirical indices were used to assess the utilization of the ash and its tendency to create slagging and fouling deposits in industrial boilers during the combustion process. It was concluded from the obtained results that the use of maritime pine non-debarked wood chips can significantly contribute to the formation of slagging and fouling phenomena in industrial boilers. These phenomena will be responsible for a higher number of technical stoppages of the equipment and for an increase in maintenance costs. [ABSTRACT FROM AUTHOR]

There is a growing demand for alternative forms of energy that could firstly replace fossil fuels, with the environmental advantages resulting therefrom, but that could be as well economically more beneficial by allowing companies to obtain competitive advantages from the aforementioned alternative forms of energy. In this sense, the use of waste to produce thermal energy is presented as an alternative worthy of study. In this paper, an analysis is made of the use of waste from the textile industry, more precisely cotton waste, which is used as a renewable resource for the production of thermal energy. After the characterization of the waste, the energetic potential is determined comparatively to other fuels such as woodchips and wood pellets. A comparative economic assessment with other fuels is carried out. The obtained results show that the cotton briquettes have a heating value of 16.80 MJ/kg and a cost of 0.006 €/kWh when used as fuel. This predicts an annual reduction in fuel cost of 80, 75 and 70% when compared with fuel-oil, wood pellets and wood chips, respectively. Thus, the use of cotton waste could be a viable alternative, economically and environmentally, to produce thermal energy. [ABSTRACT FROM AUTHOR]

This paper presents a home area network (HAN)-based domestic load energy consumption monitoring prototype device as part of an advanced metering system (AMS). This device can be placed on individual loads or configured to measure several loads as a whole. The wireless communication infrastructure is supported on IEEE 805.12.04 radios that run a ZigBee stack. Data acquisition concerning load energy transit is processed in real time and the main electrical parameters are then transmitted through a RF link to a wireless terminal unit, which works as a data logger and as a human-machine interface. Voltage and current sensing are implemented using Hall effect principle-based transducers, while C code is developed on two 16/32-bit microcontroller units (MCUs). The main features and design options are then thoroughly discussed. The main contribution of this paper is that the proposed metering system measures the reactive energy component through the Hilbert transform for low cost measuring device systems. [ABSTRACT FROM AUTHOR]

In this paper an overloading prevention of a private customer power distribution transformer (PDT) in an island in Portugal through the means of a new smart electric vehicle (EV) charging scheduler is proposed. The aim of this paper is to assess the repercussion of the penetration of additional power to restore the full level of EV battery state of charge (SoC) on dielectric oil deterioration of the PDT of a private industry client. This will allow EVs to charge while their owners are at work at three different working shifts during the day. In addition, the system is part of an isolated electric grid in a Portuguese Island. A transformer thermal model is utilised in this paper to assess hot-spot temperature by having the information of the load ratio. The data used for the main inputs of the model are the private industry client daily load profile, PDT parameters, the characteristics of the factory and EV parameters. This paper demonstrates that the proposed solution allows avoiding the overloading of the PDT, thus mitigating the loss-of-life, while charging all the EVs plugged-in at the beginning of each working shift. [ABSTRACT FROM AUTHOR]

Transformers are one of the more expensive pieces of equipment found in a distribution network. The transformer's role has not changed over the last decades. With simple construction and at the same time mechanically robust, they offer long term service that on average can reach half a century. Today, with the ongoing trend to supply a growing number of non-linear loads along with the notion of distributed generation (DG), a new challenge has arisen in terms of transformer sustainability, with one of the possible consequences being accelerated ageing. In this paper we carefully review the existing studies in the literature of the effect of loads and other key factors on oil-transformer ageing. The state-of-the-art is reviewed, each factor is analysed in detail, and in the end a smart transformer protection method is sought in order to monitor and protect it from upcoming challenges. [ABSTRACT FROM AUTHOR]

The paper discusses Home Area Networks (HAN) communication technologies for smart home and domestic application integration. The work is initiated by identifying the application areas that can benefit from this integration. A broad and inclusive home communication interface is analysed utilizing as a key piece a Gateway based on machine-to-machine (M2M) communications that interacts with the surrounding environment. Then, the main wireless networks are thoroughly assessed, and later, their suitability to the requirements of HAN considering the application area is analysed. Finally, a qualitative analysis is portrayed. [ABSTRACT FROM AUTHOR]

Global warming's major cause is the emission of greenhouse-effect gases (GHG), especially carbon dioxide (CO 2) whose main source is the combustion of fossil fuels. Fossil fuels serve as the primary energy source in many industries, including shipping, which is the focus of this study. One of the measures proposed to tackle GHG emissions is the development of green shipping corridors - carbon-free shipping routes that require the transition to alternative fuels, which are gaining competitiveness. One of the reasons for that is carbon pricing, which taxes CO 2 emissions. However, the lack of consensus on the most cost-advantageous alternative fuel in the long run results in the delay of the implementation of green shipping corridors. To make it more accessible for stakeholders to conduct an economic analysis of the various options, a framework to determine and minimize the costs of transitioning from fossil fuels to any alternative fuel is proposed, over the period of one voyage, considering the lost opportunity cost, the deployment cost of bunkering vessels at the necessary call ports, the cost of converting the vessel, the car-bon emissions tax cost, and the fuel cost. This will allow stakeholders to choose the most economical alternative fuel, accelerating the development of green shipping corridor initiatives. To validate the effectiveness of the framework, it was applied in a case study involving a shipowner seeking to transition from heavy fuel oil (HFO) to Ammonia, Hydrogen, Liquefied Natural Gas (LNG), or Methanol. This study faced limitations due to the unknown costs of installing bunkering vessels for Ammonia and Hydrogen. However, it evaluates the cost-effectiveness of alternative fuels, providing insights into their short-term economic viability. The results showed that Hydrogen is the most cost-advantageous fuel until a deployment cost per bunkering vessel of 1,990,285$ for a sailing speed of 22 knots and 2,190,171$ for a sailing speed of 18 knots is reached, after which LNG becomes the most economical option regardless of variations in the carbon tax. Moreover, a sensitivity analysis was conducted to determine the effects of variations in parameters, such as carbon tax, fuel prices and vessel conversion costs in the total cost of each fuel option. Results highlighted that even though HFO remains the most economical fuel option, even when considering a high increase in carbon tax, the cost gap between HFO and alternative fuels narrows significantly with the increase in carbon tax. Furthermore, the sailing speed impacts the fuels' competitiveness, as the cost difference between HFO and alternative fuels decreases at higher speeds. • A tool has been developed to guide the transition from fossil fuels, towards green shipping corridors. • An analysis was conducted to determine if increasing carbon taxes would make alternative fuels more financially viable than HFO. • The study identifies hydrogen as cost-advantageous, followed by LNG, influenced by varying carbon taxes. • Results demonstrated that HFO is still the most economical fuel option, even considering a very high carbon tax. • Challenges lie in uncertain bunkering vessel costs, potential profit, and the need for a model extension for fleet use. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) technologies have demonstrated a promising material efficiency potential in comparison to traditional material removal processes. A new directed energy deposition (DED) category AM process called wire arc additive manufacturing (WAAM) is evolving due to its benefits which include faster build rates, capacity to build large volumes, and inexpensive feedstock materials and machine tools compared to more technologically mature powder-based AM technologies. However, WAAM products present challenges like poor surface finish and lower dimensional accuracy compared to powder-based processes or machined parts, prevalence of thermal distortions, residual stresses, and defects like porosity, cracks, and humping, often requiring post-processing operations like finish machining and heat treatment. These post-processing operations add to the production cost and environmental footprint of WAAM-built parts. Therefore, considering the opportunities and challenges presented by WAAM, this paper analyses the environmental impact, production costs, and mechanical properties of WAAM parts and compares them with those achieved by laser powder bed fusion (LPBF) and traditional computer numerical control (CNC) milling. A high-strength low-alloy steel (ER70S) mechanical part with medium complexity was fabricated using WAAM. Based on the data collected during this experiment, environmental impact and cost models were built using life cycle assessment and life cycle costing methodologies. WAAM was observed to be the most environmentally friendly option due to its superior material efficacy than CNC milling and has a better energy efficiency than LPBF. Also, WAAM was the most cost-friendly option when adopted in batch production for batch sizes above 3. The environmental and cost potential of WAAM is amplified when used for manufacturing large products, resulting in significant material, emission, and cost savings. The fabricated WAAM part demonstrated good mechanical properties comparable to that of cast/forged material. The methodology and experimental data presented in this study can be used to calculate environmental impacts and costs for other products and can be helpful to manufacturers in selecting the most ecofriendly and cost-efficient manufacturing process. [ABSTRACT FROM AUTHOR]

The traditional method of manufacturing propellant tanks for rockets and spaceships involves significant amounts of forging, and machining, making it expensive and environmentally unfriendly. A novel approach for manufacturing propellant tanks that reduces the need for machining and friction stir welding processes has been presented in this paper. This approach involves manufacturing a tank half starting from a single metal plate, using innovative and advanced metal forming processes such as hot stretch forming, magnetic pulse forming, hub forming, and integrated stiffened cylinder (ISC) flow forming followed by orbital welding of two tank halves. A life cycle assessment (LCA) study was conducted in accordance with ISO 14044:2006 standard using the ReCiPe 2016 Midpoint (H) method to compare the environmental impacts of the traditional and newly developed approaches for manufacturing propellant tanks. The results of the LCA study showed that the new approach based on advanced forming technologies reduced carbon footprint by 40%, cumulative energy demand by 35%, water footprint by 17%, and materials waste by 4% compared to traditional manufacturing. The lower environmental impact of the new approach was attributed to a decrease in friction stir welding requirements due to the implementation of advanced forming techniques that enable integrated tank production. This lowered the overall energy consumption in the novel approach by a factor of 1.5 and in turn resulted in lower environmental impact compared to traditional forging and machining-based method. Furthermore, a futuristic scenario that involves in-house tank production using the novel approach with minimal transportation of inventories was also simulated. Based on the LCA results, it was seen that the newly developed approach for manufacturing propellant tanks was more environmentally friendly than the traditional approach and its environmental footprint could be further reduced by implementing the futuristic scenario with minimal transportation. This novel approach is also expected to reduce the lead time and production cost of manufacturing a propellant tank. Hence, future efforts in cost assessment and further optimization of raw material and energy usage are recommended. [ABSTRACT FROM AUTHOR]

In the field of the automotive painting industry, the conventional cleaning process uses solvents and high amounts of water to clean different substrates. However, not all solvents are suitable for every type of material, so different types of solvents should be used in order to successfully clean different types of material, as the product under fabrication changes, otherwise, a compromise has to be reached. The current cleaning operation system and respective apparatus occupies a significant area of the industrial facility and uses abundant water. Such use of water requires subsequent drying of the cleaned parts and for residual water treatment, leading to high running costs. In this sense, dry ice blasting appears as an alternative to the current process. This method consists of the projection of solid carbon dioxide particles onto a surface as a means of eliminating stains and contaminants prior to the painting. It is suitable for a wider range of substrates, and the necessary equipment occupies significantly less space when compared with the current process. Thus, there is potential for cost savings. In an industrial painting context, this application is considered new, although its physical principle has been established since the late 1980s. The present study aims to qualitatively evaluate the dry ice blasting process according to the quality standards of an industrial unit. Two types of plastic substrates for automotive parts are tested on-site by using a manual dry ice blasting kit, subject to the normal painting process, and then analyzed according to industrial standards. The results show that the process under study meets all the required quality standards. After being painted, the average number of stains per piece is of the same order of magnitude as the normal production, emphasizing that the average primary stains are lower in the process under study. CO 2 emissions and cleaning time is greatly reduced, the cleaning runtime decreased by 96.9% if the dry ice is used as an alternative. The viability of dry ice blasting in the pre-painting of plastic surfaces was demonstrated, and the eco-innovation of the new process discussed. • Application of dry ice blasting in automotive painting industry. • The process under study meets all the required quality standards. • Viability of dry ice blasting in pre-painting of plastic surfaces is demonstrated. • CO 2 emissions and cleaning time is greatly reduced. • The cleaning runtime decreased by 96.9% if the dry ice is used. [ABSTRACT FROM AUTHOR]

Industrial symbiosis, which allows entities and companies that traditionally be separated, to cooperate among them in the sharing of resources, contributes to the increase of sustainability with environmental, economic and social benefits. Examples of industrial symbiosis have grown over the years with increasing geographic dispersion. Thus, through a comprehensive review of previous studies, this work aims to trace the trend of industrial symbiosis research and to map the existing case studies around the world, with a critical analysis of its impact. The analysis of the 584 selected publications allowed tracing the evolution of these according to their content and the type of article, as well as its distribution by journals. Based on the literature review, the main lines for research in industrial symbiosis are assessed, as well as an updated study of the published case studies is provided with emphasis on the location, type of industry and employed methodologies. Several challenges are then identified for future research. The results reveal the number of articles on industrial symbiosis has greatly increased since 2007 and China is the country with the largest number of publications and cases of industrial symbiosis, followed by the United States. The methods for quantifying impacts and analysing industrial symbiosis networks were the most widely used. The analysis of the published case studies allowed an overview of the industrial symbiosis in the world and showed that the potential for application is enormous, both in developed countries and in countries with developing economies, and although the most present economic activities in the synergies are associated with the manufacturing sector, the possibilities of industrial symbiosis are not restricted to these activities nor to the number of entities involved. The symbioses between industry and the surrounding community also have great potential for development with numerous advantages for both parties. [ABSTRACT FROM AUTHOR]

The amount of energy generated from a photovoltaic installation depends mainly on two factors—the temperature and solar irradiance. Numerous maximum power point tracking (MPPT) techniques have been developed for photovoltaic systems. The challenge is what method to employ in order to obtain optimum operating points (voltage and current) automatically at the maximum photovoltaic output power in most conditions. This paper is focused on the structural analysis of mathematical models of PV cells with growing levels of complexity. The main objective is to simulate and compare the characteristic current-voltage (I-V) and power-voltage (P-V) curves of equivalent circuits of the ideal PV cell model and, with one and with two diodes, that is, equivalent circuits with five and seven parameters. The contribution of each parameter is analyzed in the particular context of a given model and then generalized through comparison to a more complex model. In this study the numerical simulation of the models is used intensively and extensively. The approach utilized to model the equivalent circuits permits an adequate simulation of the photovoltaic array systems by considering the compromise between the complexity and accuracy. By utilizing the Newton–Raphson method the studied models are then employed through the use of Matlab/Simulink. Finally, this study concludes with an analysis and comparison of the evolution of maximum power observed in the models. [ABSTRACT FROM AUTHOR]

The ocean thermal energy conversion (OTEC) systems, as renewable energy-based power plants, have the potential to play a significant role in meeting future electricity demands due to the vast expanse of the world's oceans. These systems employ the temperature difference between surface ocean waters and deep ocean waters to drive a thermodynamic cycle and produce electricity. The temperature of deep ocean waters, approximately 1000 m below the surface, is approximately 4 °C, while surface ocean temperatures typically range between 20 and 30 °C. The generated power of OTEC systems is dependent on these temperature differences and may vary with changes in surface ocean temperatures. In this study, the main focus is to find the impact of temperature variation on the failure rates of OTEC system components and the generated power output of these plants. The findings indicate that as the demand for the power system increases, its reliability decreases. In order to improve the reliability of the power system, the integration of a new generation unit, such as the close cycle OTEC power plant under investigation, could be necessary. The findings also indicate the importance of considering temperature variation in the evaluation of the reliability of such types of power plants based on renewable energy. [ABSTRACT FROM AUTHOR]

Rural fires are currently one of the main global disasters, and Portugal is among the countries that have suffered from them for decades. These fires pose economic, environmental, and social threats to the country. A primary cause of rural fires is the burning of biomass to clear agroforestry residues. Thus, combating rural fires requires more effective forest management, particularly the removal of forest residues that serve as fuel. These residues, also known as biomass, have significant potential for energy production and biofuel use. This paper proposes a model that integrates the PROMETHEE decision-making method with the roadmapping. This proposed model includes 7 steps, including the planning of the roadmap, the definition of the decision problem, gathering information and building the roadmap. The proposed model was applied to develop a roadmap proposal for the recovery of surplus agroforestry biomass in Portugal, identifying the most emerging conversion technologies in the national context. With the roadmap developed, it was possible to understand that the recovery of surplus agroforestry biomass in Portugal involves several sectors. The energy sector is one of those that can benefit from the recovery of leftover agroforestry biomass, both from the point of view of carbon neutrality and energy independence. Forestry management is another of the great advantages of recovering leftover forestry biomass and, consequently, reducing the number of fires. In the context of recovery, combustion is the most widely used technology for producing energy or heat. The technology identified as most emerging in the upcoming years is gasification. Investment in scientific research is essential for the success of this sector, as is the development of public incentive policies and more engagement from all stakeholders. This paper conclude that valorizing agroforestry residues can reduce rural fire risks while promoting energy independence, sustainable regional development, and innovation in Portugal. • The paper proposes an integrated PROMETHEE II-Roadmap model. • The proposed model is applied to the valorization of residual agroforestry biomass in Portugal (RAFB). • Benefits of RAFB valorization include reduction of rural fires, increased renewable energy alternatives, and sustainable regional development. • An evaluation of biomass conversion technologies is performed, and gasification is identified as the most emerging. • The paper emphasizes the need in the sector for research investment, stakeholder engagement and development of supply chains. [ABSTRACT FROM AUTHOR]

The biomass industry is growing due to the current search for greener and more sustainable alternatives to fossil energy sources. However, this industry, due to its singularity, presents several challenges and disadvantages related to the transportation of raw materials, with the large volumes that are usually involved. This project aimed to address this internal logistics situation in torrefied biomass pellets production with two different biomass storage parks, located in Portugal. The main park receives raw material coming directly from the source and stores it in large amounts as a backup and strategic storage park. The second park, with smaller dimensions, precedes the production unit and must be stocked daily. Therefore, a fleet of transport units with self-unloading cranes is required to help to unload the biomass at the main park and transport the raw material from this park to the one preceding the production unit. Thus, the main goal was to determine the dimensions of the fleet used in internal transportation operations to minimize the idle time of the transport units using a methodology already in use in the mining and quarrying industry. This methodology was analyzed and adapted to the situation presented here. The implementation of this study allows the elimination of unnecessary costs in an industry where the profit margins are low. [ABSTRACT FROM AUTHOR]

Energy hub (EH) is a concept that is commonly used to describe multi-carrier energy systems. New advances in the area of energy conversion and storage have resulted in the development of EHs. The efficiency and capability of power systems can be improved by using EHs. This paper proposes an Information Gap Decision Theory (IGDT)-based model for EH management, taking into account the demand response (DR). The proposed model is applied to a semi-realistic case study with large consumers within a day ahead of the scheduling time horizon. The EH has some inputs including real-time (RT) and day-ahead (DA) electricity market prices, wind turbine generation, and natural gas network data. It also has electricity and heat demands as part of the output. The management of the EH is investigated considering the uncertainty in RT electricity market prices and wind turbine generation. The decisions are robust against uncertainties using the IGDT method. DR is added to the decision-making process in order to increase the flexibility of the decisions made. The numerical results demonstrate that considering DR in the IGDT-based EH management system changes the decision-making process. The results of the IGDT and stochastic programming model have been shown for more comprehension. [ABSTRACT FROM AUTHOR]

This article presents an innovative switched-capacitor based nine-level inverter employing single DC input for renewable and sustainable energy applications. The proposed configuration generates a step-up bipolar output voltage without end-side H-bridge, and the employed capacitors are charged in a self-balancing form. Applying low-voltage rated switches is another merit of the proposed inverter, which leads to extensive reduction in total standing voltage. Thereby, switching losses as well as inverter cost are reduced proportionally. Furthermore, the comparative analysis against other state-of-the-art inverters depicts that the number of required power electronic devices and implementation cost is reduced in the proposed structure. The working principle of the proposed circuit along with its efficiency calculations and thermal modeling are elaborated in detail. In the end, simulations and experimental tests are conducted to validate the flawless performance of the proposed nine-level topology in power systems. [ABSTRACT FROM AUTHOR]

The principal aim of this study is to devise a combined market operator and a distribution network operator structure for multiple home-microgrids (MH-MGs) connected to an upstream grid. Here, there are three distinct types of players with opposite intentions that can participate as a consumer and/or prosumer (as a buyer or seller) in the market. All players that are price makers can compete with each other to obtain much more possible profitability while consumers aim to minimize the market-clearing price. For modeling the interactions among partakers and implementing this comprehensive structure, a multi-objective function problem is solved by using a static, non-cooperative game theory. The propounded structure is a hierarchical bi-level controller, and its accomplishment in the optimal control of MH-MGs with distributed energy resources has been evaluated. The outcome of this algorithm provides the best and most suitable power allocation among different players in the market while satisfying each player's goals. Furthermore, the amount of profit gained by each player is ascertained. Simulation results demonstrate 169% increase in the total payoff compared to the imperialist competition algorithm. This percentage proves the effectiveness, extensibility and flexibility of the presented approach in encouraging participants to join the market and boost their profits. [ABSTRACT FROM AUTHOR]

This study suggests a model to include a solar power system or photovoltaic system (PV) in the control of frequency by taking into account a percentage of the PV power production for back-up reserve. This is done by investigating two scenarios: PV contribution in (1) initial primary frequency control and (2) entire primary frequency control. As explained in section three, 10% power of the PV modules which receive more than 400 w/m2 irradiation is allocated for the power reserve. The power generation of photovoltaic systems depends largely on weather conditions which makes their output power associated with some degree of uncertainty. For this reason, in this paper, a PV system is considered along with conventional hydro and thermal units and they are modeled in MATLAB/Simulink (version 9.3, MathWorks, Natick, MA, USA) with the purpose of exploring the behavior of the intended method. In the next phase, for further studies, this system is extended to multi-area power systems including gas turbines. The results of the simulation demonstrated that the photovoltaic involvement in the control of frequency can successfully amend the frequency of the overall network. Not only it can decrease the overshoot and undershoot of the frequency response, it has the ability to improve the settling time as well, which helps the system reach the steady state easily and in shorter time. Specifically, the overshoot has reached nearly zero in both one area and two area systems and undershoot has declined up to 60% and 50% in the one area and two-area system, respectively. Considering settling time, while it had a negligible improvement in the one area system, it showed a remarkable enhancement in the two-area system, which improved from about 25 s to 6 s by using the proposed method. [ABSTRACT FROM AUTHOR]