ARTICLE | doi:10.20944/preprints202107.0241.v1
Subject: Business, Economics And Management, Accounting And Taxation Keywords: circular economy; environment; consumer
Online: 12 July 2021 (11:14:35 CEST)
The circular economy is an alternative paradigm whose purpose is the protection of the environment, the prevention of pollution and the growth of economic prosperity. This paper covers research which is qualitative in nature but has an exploratory scope through a documentary review, and includes proposals to promote sustainability. A more responsible consumption or use can be achieved by educating the user or consumer to return the product to production or repair through a collection service by way of reverse logistics (recovery of materials), followed by recycling or reuse of the product or its components to then offer these as recovered or recycled products on the market.
ARTICLE | doi:10.20944/preprints202308.2144.v1
Subject: Environmental And Earth Sciences, Sustainable Science And Technology Keywords: circular economy; circular society; Australia; intermediary
Online: 31 August 2023 (07:15:59 CEST)
Australia has recently declared its commitment to a circular economy. Policy and initiatives to date have focused on recycling and waste management and research to date has highlighted the need for more ambitious policy, clearer definitions, collaboration, and consensus on goals. There are also calls from some government and non-business sectors for more inclusive circular models, including Doughnut Economics. In a context of competing mainstream circular economy and inclusive circular society discourses, circular intermediary organizations and their representatives are key to achieving change. Compared to the green growth business narrative of policy and industry media, intermediary representatives are aware of the diversity of challenges and solutions for Australia. Based on semi-structured interviews with twenty representatives of circular intermediaries in Australia and thematic discourse analysis, this study finds circular economy, circular society and de-growth discourses informing themes about government, business, growth, consumers, society, and policy present and future. The study concludes with recommendations for a more holistic policy and practice beyond the current circularity for circularity’s sake.
REVIEW | doi:10.20944/preprints202310.0087.v1
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: sustainability; circular economy; additive manufacturing; recyclability
Online: 3 October 2023 (05:43:52 CEST)
The paper delves into an extensive exploration of the integration of the circular economy paradigm within the realm of additive manufacturing (AM). The objective is to comprehensively investigate existing methodologies for structuring the symbiotic relationship between circular economy and additive manufacturing, while meticulously analyzing the current research gap concerning the implementation of circular economy principles in additive manufacturing practices. A thorough review focusing on the sustainability of additive manufacturing within the circular economy framework was conducted. This review aims to recognize and delineate pertinent aspects related to post-use material valuation in AM, recyclability of materials, and the environmental footprint associated with these processes. Emphasis was placed on the significance of examining circular economy facets concerning additive manufacturing processes to establish a holistic understanding. The overarching goal of this review is to augment knowledge regarding the potential advantages and benefits derived from the seamless integration of circular economy principles within AM. By elucidating the activities essential to attain compliance with the Sustainable Development Goals, this study endeavors to illuminate the pathway toward promoting sustainable development through the harmonious marriage of additive manufacturing and the circular economy.
Subject: Business, Economics And Management, Economics Keywords: values of repair; circular economy; environmental justice; politicization
Online: 10 February 2021 (16:21:37 CET)
The idea of replacing the broken linear economy with circular forms to help address the current sustainability crisis is gaining world-wide traction in policy, industry, and academia. This article presents results from an international interview study with 34 repair practitioners and experts in different fields. The article aims to improve understandings of the potential of repair so as to contribute to a more just, sustainable, and circular economy. Through a five-step qualitative method the results reveal and explore three tensions inherent in repair: first, repair activities constitute different forms of subjectivity; second, repair entails different and sometimes contested temporalities; and finally, even though repair is deeply political in practice, the politics of repair are not always explicit, and some repair activities are actively depoliticized. The opportunities and obstacles embodied in these tensions are generative in repair practices and debates, but poorly reflected in contemporary circular economy discourse. We conclude that a richer, more inclusive and politicized understanding of repair can support environmental justice in the implementation of CE and provide greater opportunities for just and transformational sustainability strategies and policies.
REVIEW | doi:10.20944/preprints202205.0275.v1
Subject: Biology And Life Sciences, Ecology, Evolution, Behavior And Systematics Keywords: Circular economy; linear economic model; plastics; recycling
Online: 20 May 2022 (09:18:26 CEST)
The Circular Economy of plastics is a promising concept that has the potential to reduce pollution and close the loop on plastic waste. However, further research is needed to develop more efficient and environmentally friendly methods of recycling plastic. This review article discusses the Circular Economy of plastics, its potential benefits and drawbacks, and the challenges that need to be addressed to make it a reality. Some case studies are also examined to explore how the Circular Economy of plastics has been implemented across the globe.
REVIEW | doi:10.20944/preprints202209.0168.v1
Subject: Engineering, Civil Engineering Keywords: Keywords: Circular economy; building sector; Europe
Online: 13 September 2022 (10:04:31 CEST)
This article evaluates Europe's building sector's circular economy (CE). This industry is respon-sible for 42% of energy consumption, more than 50% of extracted materials, 30% of Europe's wa-ter and waste generation, and 35% of greenhouse gas (GHG) emissions. This study focuses on peer-reviewed articles from Scopus and Web of Science databases. Of the first 1750 publications, 2.9% were eligible for a full-text reading and analysis. Most of the trending studies, 92%, pro-mote the circular economy concept through construction materials rather than analyzing the im-pact of the construction sector on the environment and finding solutions for better implementa-tion, and 41% promote recycling and reuse as the only options. New Design solutions are in 12% of the studies, six-fold more than Law and Legislation, only 2%. Finding an optimal combination of assessing the life cycle of buildings and components and searching for different ways of man-aging the Construction and Demolition Waste at end-of-life is between 33% and 39%. Ultimately, one evaluated CE proposed frameworks for the building industry based on 10R principles varia-tions. One presents an alternative framework for a circular strategy for the building industry that focuses on Upcycling, replacing the Recover principle.
ARTICLE | doi:10.20944/preprints201806.0268.v1
Subject: Business, Economics And Management, Business And Management Keywords: Circular economy; sustainability; environmental management; resource management; strategy; motivations; knowledge; challenges.
Online: 18 June 2018 (14:15:28 CEST)
The move towards a new Circular Economy (CE) economic model has been advocated and supported in Portugal, however, there is limited research on this topic. To address this gap, a quantitative research based on an online survey was carried out among 99 Portuguese organizations, encompassing a wide range of sectors and sizes. The results show that CE is regarded as a strategic and relevant issue for profitability and value creation. Furthermore, the perception that it requires the adoption of new business models in addition to the classical “reduce, reuse, and recycle” approach is growing. Moreover, based on the hypotheses raised, results suggest that the level of CE adoption is positively impacted by the status of the EMS (Environmental Management System) certification and the willingness to improve the environmental performance and achieve a sustainable business model. However, CE activities are still relatively modest and a friendlier context (fiscal, legal, organizational, etc.) and the stronger support from supply chain agents and consumers are required. Future research should focus on how to design and shape the transition from a linear to a CE economy, and to ascertain if the positive attitude towards CE is materialized in changing the way business is done.
ARTICLE | doi:10.20944/preprints202304.1039.v1
Subject: Environmental And Earth Sciences, Water Science And Technology Keywords: Circular economy; phosphorus; struvite; valorization; wet oxidation.
Online: 27 April 2023 (04:40:57 CEST)
Environmental legislation on waste management coupled with the potential for nutrients recovery are key factors encouraging the use of advanced treatment technologies to manage biosolids waste. In this context, phosphorus recovery from a sewage sludge treated by a wet oxidation process was carried out. High organic matter (up to 85% in COD) and Total Solids content (up to 75%) removal values were achieved at elevated temperature (up to 300 ºC) and pressure (up to 200 bar) conditions. The liquid and solid fractions found in oxidation process effluent contain amounts of phosphorus that can be recovered. This research aims to maximize its valorization in both liquid and solid fractions. In the liquid effluent, phosphorus was recovered (up to 90 mg P L-1) by chemical precipitation as struvite (MgNH4PO4∙6 H2O), a slow-release fertilizer. In this case, P recoveries greater than 95% were achieved. Also, the solid fraction, analyzed after filtration and drying (68 mg P gsolid-1), was treated by acid leaching, to achieve up to 60% phosphorus recovery. All phosphorus extracted was in orthophosphate form.
ARTICLE | doi:10.20944/preprints202309.0239.v1
Subject: Environmental And Earth Sciences, Waste Management And Disposal Keywords: circular economy; solid waste management; Language R; bibliometrics
Online: 5 September 2023 (05:12:17 CEST)
The circular economy (CE) has emerged as a viable alternative for tackling the problems caused by rising consumption, including solid waste (SW). The present study conducted a meta-analysis of research published between 2012 and 2022 on CE and solid waste management (SWM). A bibliometric analysis was used from the Web of Science (WoS) and Scopus databases. By studying the articles, we briefly discussed the connections between them and how one contributes to the evolution of the other. Some findings point to greater collaboration between Italy and Bolivia, followed by China and Malaysia. However, they move away from the traditional axes as the United States and Canada. In addition, it was found that the adoption of reuse and selective collection, in fact, allow the reduction of the volume of discarded materials. In this way, it was possible to conclude that a greater connection between CE and GRS makes it possible to optimize the useful life of landfills through the treatment of organic waste and recycling, to encourage waste picker cooperatives and selective collection programs, and to reduce the financial costs of the system as a whole, making it more durable and sustainable.
REVIEW | doi:10.20944/preprints202009.0044.v1
Subject: Environmental And Earth Sciences, Environmental Science Keywords: Circular Economy; Social Aspects; Systematic Review; Sustainable Development
Online: 2 September 2020 (11:42:04 CEST)
Circular Economy (CE) is a growing topic among scholars, industry and government aiming at decoupling economic growth and development from the consumption of finite resources. CE incorporates different meanings, from reduce, reuse and recycle activities to environmental degradation or resource scarcity, and supported by specific indicators to attain sustainable development. However, so far, there has been no agreement to measure how effective an industry/product is in making the transition from linear to circular approaches, particularly those affected the society. This research work aims to perform a systematic literature review (n=60) to analyze and discuss how social aspects have been considered and integrated in the CE research so far. Moreover, this review provides and overview of the literature on social impact within CE, that resulted in three main outputs: a knowledge map of the CE, an analysis of social aspects within CE, and the theories/frameworks used to evaluate social impact of CE. Finally, this study brings to light how CE implementation can affect society and highlights the importance of social dimension in the domains of CE and policy-making community, which could help moving CE towards a sustainable development.
ARTICLE | doi:10.20944/preprints201905.0012.v1
Subject: Chemistry And Materials Science, Electrochemistry Keywords: lithium-ion battery; battery recycling; battery electric vehicle; circular economy
Online: 5 May 2019 (11:10:23 CEST)
Driven by the rapid uptake of battery electric vehicles, Li-ion power batteries are increasingly reused in stationary energy storage systems, and eventually recycled to recover all the valued components. Offering an updated global perspective, this study provides a circular economy insight on lithium-ion battery reuse and recycling.
ARTICLE | doi:10.20944/preprints201902.0023.v1
Subject: Chemistry And Materials Science, Food Chemistry Keywords: anchovy; omega-3; limonene; circular economy; fish processing waste; marine fishery discards
Online: 3 February 2019 (02:58:23 CET)
Fish oil rich in polyunsaturated omega-3 fatty acids is extracted in high yield from anchovy filleting waste using d-limonene as green biosolvent in a simple solid-liquid extraction performed by mechanically stirring and maceration followed by limonene removal via evaporation under reduced pressure. As limonene is renewably obtained from waste orange peel, this protocol establishes a circular bioeconomy method to obtain valued omega-3 extracts from biowaste available worldwide in several million t/year amount. The method closes the materials cycle and opens the route to full valorisation of an important biological resource so far mostly discarded as waste. Significant economic opportunities benefiting local communities, the ecosystem and public health are anticipated.
ARTICLE | doi:10.20944/preprints202109.0522.v1
Subject: Social Sciences, Behavior Sciences Keywords: recycled PET products; circular economy; intention to purchase.
Online: 30 September 2021 (15:06:49 CEST)
Circular Economy involves structural changes in traditional business models and consumers’ behaviour toward recycled products. The recycling of PET products has been increasing but there is still a gap between consumption and demand for PET packaging in Brazil. In this research, the waste reduction was examined under a projective scenario to the current ecological purposes in Brazil for reducing environmental pollution. In that manner, this paper aimed to comprehend the intention to purchase recycled PET products of Brazilian consumers. With a non-probabilistic and convenience sample, the study counts 422 participants. The method employed was based on Structural Equation Modelling and Partial Least Squares, used to test the hypotheses of causality among the variables. Results showed the perception of low quality about recycled products reduced consumers’ intention to purchase. Also, the sustainability of recycled products positively influenced the intention to purchase. In addition, recycled products presented a negative impact on the perceived safety, which could influence the purchase of recycled products in Brazil. We conclude that the image that Brazilian consumers have about recycled products positively affects the intention to purchase.
ARTICLE | doi:10.20944/preprints201811.0128.v1
Subject: Chemistry And Materials Science, Other Keywords: circular economy; education; reuse; sustainability; self-produced materials; waste
Online: 6 November 2018 (04:40:59 CET)
The article presents an experience based on the design of DIY materials (Do-It-Yourself) as a phenomenon that contributes to the circular economy, making use of household waste and organic binders. The development context is the southernmost Industrial Design School in Latin America, where students are educated through the transfer of knowledge emphasized on the experimentation and territory assessment. Methodology corresponds to the traditional industrial design process, inserting DIY design of materials in the strategic stage. Objective and subjective variables are determined applied in the definition of new materials, being able to determine a range of proposals based on household waste. Citrus × Sinensis, Peperomia caperata (Piperaceae), Radiata pine veneers, among them, which are conceived by students to be self-produced at the user level. The results are materials elaborated based on household waste, exemplified with three types based on organic husks. Beyond findings associated to technique, compatibilities between residual materials and results expressed in materials and catalogs, it is possible to educate future designers on the innovative theme, with the potential to improve life quality of people and their environments.
ARTICLE | doi:10.20944/preprints201712.0112.v1
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: life cycle assessment; circular economy; material efficiency; recycling; reuse
Online: 18 December 2017 (06:36:56 CET)
Material efficiency is a key element of new thinking to address the challenges of reducing impacts on the environment and of resource scarcity, whilst at the same time meeting service and functionality demands on materials. Directly related to material efficiency is the concept of the Circular Economy, which is based on the principle of optimising the utility embodied in materials and products through the life cycle. Whilst steel, as a result of high recycling rates, is one of the most ‘circular’ of all manufactured materials, significant opportunities for greater material efficiency exist, which are yet to be widely implemented. In the field of Life Cycle Management, Life Cycle Assessment (LCA) is commonly used to assess the environmental benefits of recovering and recycling materials through the manufacturing supply chain and at end-of-life. As well as containing information to calculate environmental impacts, LCA models also provide the flows of materials through the product life cycle and can also be used to quantify material efficiency and the circularity of a product system. Using an example taken from renewable energy generation, this paper explores the correlation between product circularity and the environmental case for strategies designed to improve material efficiency. An LCA-based methodology for accounting for the recovery and re-use of materials from the supply chain, and at end-of-life, is used as the basis for calculating the carbon footprint benefits of five material efficiency scenarios. Resulting carbon footprints were then compared with a number of proposed material circularity indicators. Two conclusions from this exercise were that i) LCA methodologies based around end-of-life approaches are well placed for quantifying the environmental benefits of material efficiency and circular economy strategies and ii) when applying indicators relating to the circularity of materials these should also be supported by LCA studies.
ARTICLE | doi:10.20944/preprints202011.0359.v1
Subject: Business, Economics And Management, Accounting And Taxation Keywords: Circular economy; Sustainable development; EU countries; Ranking; Classification
Online: 12 November 2020 (18:10:48 CET)
In this paper, we have analysed the level of advancement in circular economy (CE) in the EU-28 countries. Firstly, we used a synthetic measure to examine CE advancement in EU countries in each of the Eurostat CE distinguished areas, i.e. production and consumption, waste management, secondary raw materials, and competitiveness and innovation. For the empirical analysis, we applied 17 Eurostat indicators to the CE areas. To find the synthetic measure in 2010, 2012, 2014, and 2016, we used multidimensional comparative analysis, i.e. a zero unitarisation method. Secondly, based on the synthetic measures of the CE areas, we created a general synthetic measure of the CE advancement of the EU-28 countries as well as the countries’ rankings. Thirdly, we classified the countries into groups according to their level of advancement in CE, i.e. high level, medium-high level, medium-low level, and low level groups. Finally, we applied a similarity measure to evaluate the correlation between obtained rankings in two most extreme moments in the period of analysis (2010, 2016). Our analysis covers all EU member states, as well as "old" and "new" EU countries separately. Our results confirm that highly developed Benelux countries, i.e. Luxembourg, the Netherlands, and Belgium, have the highest CE advancement level. Malta, Cyprus, Estonia, and Greece are the least advanced in CE practice. Apart from that, on average, there is some progress in CE implementation, significant disproportions between the EU countries were observed, especially among the "new" member states.
ARTICLE | doi:10.20944/preprints201908.0251.v1
Subject: Environmental And Earth Sciences, Environmental Science Keywords: anthropogenic mineral; recycling; circular economy; metals; urban mining
Online: 25 August 2019 (15:15:47 CEST)
An increasingly large quantity of primary mineral resource is being converted into manufactured products and destined for solid waste disposal. This material can be reclassified as “anthropogenic mineral reserves” and be a potential source of metals for a range of manufacturing uses. China is implementing a range of policy interventions which can lead to such a classification that will raise the profile of recycling programs as a means of metal supply. China is not only a major producer of consumer products and importer of secondary metals, but also has a major urban infrastructure footprint. Here we consider three product groups, 30 products, and imports, and map the recycling potential of anthropogenic mineral and 23 types of the capsulated materials by targeting their evolution from 2010 to 2050. Total weight of anthropogenic mineral on average in China reached 39 Mt in 2010, but it will double in 2022 and quadruple in 2045. Stocks of precious metals and rare earths will increase faster than most base materials. The total economic potential in yearly-generated anthropogenic mineral is anticipated to grow markedly from 100 billion US$ in 2020 to 400 billion US$ in 2050. Anthropogenic mineral of around 20 materials will be able to meet projected consumption of three product groups by 2050, due to high availability of recycled content and gradual saturation of consumption. Durability of material usage and the concomitant stock of the anthropogenic mineral remain major challenges in determining the viability of this supply in the second half of the coming century.
Subject: Social Sciences, Geography, Planning And Development Keywords: circular economy; social ecology; consumerism; dialectical naturalism; mining
Online: 12 September 2016 (09:55:09 CEST)
The concept of a "circular economy" needs a more cogent theoretical anchor which will allow for transference of its goals and methods of attainment across cases. Tensions between ecological goals of this concept and the social implications of its implementation need to be addressed. This paper attempts to provide a theoretical framework for harnessing the strengths of a circular economy. Building on theories of social ecology which are predicated in Murray Bookchin's notion of "dialectical naturalism", the analysis presented here addresses some of the criticism of circular economic paradigms, such as their potential for stifling innovation or a neglect of human development challenges. A model for managing human "need" and "greed" within a circular economy framework is presented that also incorporates consumer choice and innovation. Planned obsolescence as a means of livelihood generation is also problematized with a view towards balancing durability of products on the one hand and ensuring throughput for manufacturing employment and innovation incentives on the other. Finally, the need for governance systems is considered to ensure that a planetary vision for a circular economy can be realized that efficiently harnesses local initiatives rather than an atomized and insular view of circularity.
ARTICLE | doi:10.20944/preprints202309.1170.v1
Subject: Engineering, Civil Engineering Keywords: Wastewater; Circular Economy; Life Cycle Sustainability Assessment; Decision Making
Online: 18 September 2023 (10:25:55 CEST)
The wastewater circular economy (WW-CE) promises a solution to improve water and sanitation management worldwide. However, the transition from conventional to circular wastewater treatment plants (WWTPs) requires facilitation to aid in decision makers understanding of integral sustainability impacts of alternative WW-CE configurations. This research implemented Life Cycle Sustainability Assessment (LCSA), combining Life Cycle Assessment, Social Life Cycle Assessment and Life Cycle Costing with a Multi-criteria Decision Making (MCDM) model to quantify environmental, socio-cultural, and economic impacts of conventional WWTPs with the WW-CE. Two real WWTPs in Chile have embraced the WW-CEs and adopting the title of Biofactories. These were considered as case studies, compared under three scenarios to demonstrate the sustainability trade-offs of the transition from no sanitation to conventional WWTPs and Biofactory WW-CE configurations. Results demonstrated that the transition to WW-CEs improved integral sustainability according to the LCSA model implemented in both WWPTs. This study highlights the urgent need to adopt sustainable decision-making models to not only improve sanitation coverage, but also improve sustainability performance of the sanitation industry across the globe.
REVIEW | doi:10.20944/preprints202209.0365.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: pineapple; wastes; biorefinery; COVID-19; circular economy; biomedical.
Online: 23 September 2022 (09:22:33 CEST)
Pineapple is a highly demanded fruit in international markets, thanks to its unique appearance and flavor, high fiber content, vitamins, folic acid, and minerals. It makes the pineapple production and processing market a significant source of income for producing countries, such as Costa Rica. Nowadays, its processing produces a large amount of waste with negative consequences for the environment. However, pineapple waste is an essential source of cellulose, hemicellulose, lignin, and other high-value products like enzymes (bromelain). These by-products can be obtained by pineapple waste biorefinery, generating an additional source of export goods and foreign currency, framing pineapple processing in the concept of the circular economy. This review discusses how incorporating biorefinery in the pineapple production processes can contribute to the post-COVID 19 economy in Costa Rica. Pineapple production in Costa Rica is explored, and the contamination of generated residues is delineated. Furthermore, the primary processes for by-product extraction via biorefinery, their general characteristics and applications in the medical field, and their contribution to the circular economy are presented.
ARTICLE | doi:10.20944/preprints201712.0146.v2
Subject: Business, Economics And Management, Business And Management Keywords: Circular Economy; sustainability; family business; model; case study; Mercadona
Online: 22 February 2018 (10:33:56 CET)
Sustainability addresses environmental and social issues affecting this and future generations. When family businesses perceive that the community is disrupted, recognize an environmental problem and respond by implementing new environmental policies or regulations, the family business’s socio-emotional values press to transition to a more sustainable production system, such as the ‘Circular Economy.’ Drawing on the Dubin (1978) methodology—a paradigm for building models through deduction—we design a sustainable model, which shows family businesses’ responses to changes in the environment. It explains the reasons why family firms transition to the Circular Economy, based on the theory of Socio-Emotional Wealth (SEW). We check the model through the case study of the food retail leader in the Spanish market—Mercadona—which applies policies about energy, resources and waste to become a Circular Economy business model. Because of the strong family character of Mercadona, this case can be useful for the decision-making of other family businesses.
REVIEW | doi:10.20944/preprints202204.0192.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: pineapple; wastes; biorefinery; COVID-19; circular economy; biomedical
Online: 21 April 2022 (07:54:36 CEST)
Pineapple is a highly demanded fruit in international markets, thanks to its unique appearance and flavor, high fiber content, vitamins, folic acid, and minerals. It makes the pineapple production and processing market a significant source of income for producing countries, such as Costa Rica. Nowadays, its processing produces a large amount of waste with negative consequences for the environment. However, pineapple waste is an essential source of cellulose, hemicellulose, lignin, and other high-value products like enzymes (bromelain). These by-products can be obtained by pineapple waste biorefinery, generating an additional source of export goods and foreign currency, framing pineapple processing in the concept of the circular economy. This review discusses how incorporating biorefinery in the pineapple production processes can contribute to the post-COVID 19 economy in Costa Rica. Pineapple production in Costa Rica is explored, and the contamination of generated residues is delineated. Furthermore, the primary processes for by-product extraction via biorefinery, their general characteristics and applications in the medical field, and their contribution to the circular economy are presented.
REVIEW | doi:10.20944/preprints202310.0729.v1
Subject: Engineering, Mechanical Engineering Keywords: circular economy; circularity assessment; industries; circularity enhancement; digital tools
Online: 11 October 2023 (12:20:59 CEST)
Circular economy has recently emerged as a key strategy for promoting sustainability and reducing waste in various industrial sectors. This paper provides an overview of circularity in aerospace, wind energy, transportation, automotive and sports goods using data and information from the literature and the EC funded project "RECREATE". The survey reviews the different definitions, assessment methods and metrics used to explore and evaluate circularity, including assessment frameworks such as Life Cycle Assessment (LCA) and assessment indicators. Furthermore, explores the challenges, possibilities and the available tools for enhancing circularity, such as digital tools. The survey highlights the importance of a holistic and systemic technique to circularity, concerning all stakeholders along the value chain. Overall, this study aims to contribute to a better understanding of circular economy and provides insights for future research.
REVIEW | doi:10.20944/preprints202308.0674.v1
Subject: Social Sciences, Sociology Keywords: circular economy; planetary boundaries; green lifestyle; moral licensing
Online: 8 August 2023 (11:56:45 CEST)
The concept of an economy that is circular and without the need for material or energy input has an irresistible appeal to those who have recognized that planetary boundaries exist and that resources are not unlimited. Thus, in the public discourse its narrative outperforms other lines of arguments when it comes to keeping radical critics of destructive extractivism and the growth imperative in check and averting the uptake of diverging opinions by larger segments of the population and government bodies. Moreover, the myth of a circular economy has the additional benefit that it can win over parts of the environmental movement that dread radical and transformative change, particularly in the urban milieus of a middle-class that enjoys the privileges of the current social order. In this paper I argue that the circular economy narrative tends to hinder the necessary systemic transformation while entailing a wide range of specific measures that deserve to be recognized for their merit.
COMMUNICATION | doi:10.20944/preprints202310.0027.v1
Subject: Engineering, Architecture, Building And Construction Keywords: circular economy; building information modeling; built environment; building sector; digitalization
Online: 2 October 2023 (04:05:45 CEST)
With the advent of digitization, the integration of advanced technologies in operations and projects across all sectors is in progress. Accordingly, efforts are being made to utilize cutting-edge technologies to improve the circularity of the built environment. This study aimed to review the existing applications and limitations of building information modeling (BIM) tools for circular economy (CE) implementation from this perspective. A literature review was conducted to provide an overview of the use of BIM tools for conducting life cycle assessments, energy analysis, waste management, and formulation of material passports for buildings. It was found that BIM tools, which are available across all life cycle phases of building, have a great potential to improve the circularity of the sector. The overview provided on the use of various BIM tools may help stakeholders of the built environment understand the role of BIM for CE adoption in the sector.
ARTICLE | doi:10.20944/preprints202205.0045.v1
Subject: Environmental And Earth Sciences, Environmental Science Keywords: circular economy; eco-design; business education; economics education; competencies; Management Education; ADKAR
Online: 5 May 2022 (15:57:09 CEST)
The Circular Economy is matter of recent discussions and quite popular, however the meaning has not been understood by most Business stakeholders. This Case study proposes to illustrate the Circular Economy importance and its status now. The contribution that UAE education sector can make to the Circular Economy is immense and is the focus of this study. Circular Economy awareness and its inner meaning can be only spread by the education sector and the author emphasizes the role of the education can play in implementing the Circular Economy. The study shows the way for the future Managers and Business stakeholders to participate in this crucial endeavor of Businesses to follow the Circular Economy. The ADKAR change management can be adopted to inspire the CE initiatives of the UAE Education sector.
REVIEW | doi:10.20944/preprints201808.0159.v1
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: circular economy; industry 4.0; data; 9R’s; digital technologies; digital intelligence
Online: 8 August 2018 (05:31:47 CEST)
The Circular Economy has been of growing significance within academic, policymaking and industry groups. Latest developments in the field of Circular Economy has led to an expansion of CE studies focused on interrogating CE as a paradigm, its relationship with sustainability and concepts and definitions of the Circular Economy. Research has also identified the significant potential of applying circular approaches to areas of the economy, including manufacturing and Industry 4.0, which, with data, is enabling latest the advances in digital technologies. This is the first review paper to integrate the fields of CE and digital technologies resulting in a framework which provides directions for policymakers and guidance for future research. To achieve this, we conduct a systematic literature review of the empirical literature related to digital technologies, industry 4.0 and circular approaches, from the point of the 9 Rs. The systematic literature review (SLR) is based on peer-reviewed articles published between 2000-2018. The findings reveal that while research on the circular economy has been on an annual rise, research on digital technologies enabled circular economy is still relatively an untouched area of research across all nine (9) circular approaches. As such this is an area rife for further research. This paper also presents illustrative charts and graphs to summarize the current trends in circular economy research in manufacturing. From this, a framework for future circular economy research for manufacturing for digital technologies is proposed.
ARTICLE | doi:10.20944/preprints202305.0046.v1
Subject: Business, Economics And Management, Business And Management Keywords: textile industry; clothing industry; sustainable development; circular economy; CE; digital technology; digitalisation; corporate social responsibility; CSR.
Online: 2 May 2023 (03:01:09 CEST)
The textile and clothing (T&C) industry is not usually viewed as an exemplar of sustainable de-velopment and the circular economy, as the industry has hitherto made its products in linear fashion, with relatively little recycling of the finished goods. This article examines the industry’s approach to the core sustainability concept and the circular economy in particular, through a re-view of the available academic literature, evidence from corporate sustainability reports and websites, and feedback from an online survey of industry professionals. The role of digital technology deployment in engendering sustainability and the circular economy in the industry is also explored. The study finds that whilst sustainability is now firmly embedded at the strategic level in the vast majority of companies studied, attitudes towards the circular economy remain fickle. The use of digital technologies in support of sustainability objectives is also limited at present, but the article concludes that the need to meet compliance requirements and new cus-tomer perceptions of sustainability will speed the transition to circular economy activities, facili-tated by greater exploitation of digital technologies. Building upon the research findings, existing models and an initial conceptual framework, a simple operational model for initiating such a transition for small-to-medium sized enterprises in the T&C industry is put forward.
REVIEW | doi:10.20944/preprints202111.0518.v1
Subject: Biology And Life Sciences, Insect Science Keywords: polystyrene; polyethylene; worms; Hermetia illucens; Tenebrio molitor; Zophobas morio; plastic; bioremediation; food-waste; circular economy
Online: 29 November 2021 (09:47:04 CET)
The negative impact of the modern-day lifestyle on the environment is aggravated during the COVID-19 pandemic through the increased use of single-use plastics from food takeaways to medical supplies. Similarly, the closure of food outlets and disrupted supply chains have also resulted in significant food wastage. As the pandemic rages on, the aggravation of increased waste becomes an increasingly urgent problem that threatens the biodiversity, ecosystems, and human health worldwide through pollution. While there are existing methods to deal with the organic and plastic waste, many of the solutions also cause additional problems. Increasingly proposed as a natural solution to man-made unnatural problems, there are insect solutions for dealing with the artificial and organic waste products towards a circular economy, making the use of natural insect solutions commercially sustainable. This review discusses the findings and how some of these insects, particularly the Hermetia illucens, Tenebrio molitor, and Zophobas morio, can play an increasing important role in food and plastics, with a focus on the latter.
ARTICLE | doi:10.20944/preprints202003.0264.v1
Subject: Environmental And Earth Sciences, Waste Management And Disposal Keywords: recycling; composting; waste-to-energy; incineration; municipal solid waste; circular economy; green jobs
Online: 17 March 2020 (03:46:53 CET)
Sharing the same raw material, recycling and composting are in direct conflict with incineration of municipal solid waste in combined heath and power plants. Indeed, waste-to-energy plants in regions with high recycling rates import urban waste from other countries to use otherwise unused capacity, and raise revenues. Using the case of Italy’s second largest and economically most developed region, I discuss the economic viability of municipal solid waste incineration to produce electricity and heath in the context of the increasing role of electricity production from renewable energy sources as well as of the emerging mass-scale uptake of bioplastics. Four lessons and three guidelines aimed to local authorities and policy makers emerge from the present study.
ARTICLE | doi:10.20944/preprints202107.0276.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: life cycle assessment; sisal production; circular economy; nutrient depletion; anaerobic digestion; waste management; bioenergy; biogas.
Online: 12 July 2021 (23:02:10 CEST)
Nutrient depletion in Tanzanian sisal production has led to yield decreases over time. We use nutrient mass balances embedded within a life cycle assessment to quantify the extent of nutrient depletion for different production systems, then used circular economy principles to identify potential cosubstrates from within the Tanzanian economy to anaerobically digest with sisal wastes. The biogas produced is then used to generate bioelectricity and the digestate residual can be used as a fertilizer to address the nutrient depletion. If no current beneficial use of the cosubstrate was assumed, then beef manure and marine fish processing waste were the best cosubstrates. If agricultural wastes were assumed to have a current beneficial use as fertilizer, then marine fish processing waste and human urine were the best cosubstrates. The largest reduction in environmental impacts resulted from bioelectricity replacing electricity from fossil fuels in the national electricity grid and improved onsite waste management practices. There is significant potential to revitalize Tanzanian sisal production by applying circular economy principles to sisal waste management and bioenergy production.
ARTICLE | doi:10.20944/preprints202011.0438.v1
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: Life cycle assessment; circular economy; multiple product life cycles; temporal variability; life cycle inventory; emission intensity
Online: 16 November 2020 (17:24:26 CET)
Life cycle assessment (LCA) is used frequently as a decision support tool for evaluating different design choices of products based on their environmental impacts. A life cycle usually comprises several phases of varying timespan. The amount of emissions generated from different life cycle phases of a product could be significantly different from one another. In conventional LCA, the emissions generated from the life cycle phases of a product are aggregated at the inventory analysis stage, which is then used as an input for life cycle impact assessment. However, when the emissions are aggregated, the temporal variability of inventory data is ignored, which may result in inaccurate environmental impact assessment. Besides, the conventional LCA does not consider the environmental impact of circular products with multiple use cycles. It poses difficulties in identifying the hotspots of emission-intensive activities with the potential to mislead conclusions and implications for both practice and policy. To address this issue and to analyse the embedded temporal variations in inventory data in a CE context, the paper proposes to calculate the emission intensity for each life cycle phase. It is argued that calculating and comparing emission intensity, based on the timespan and amount of emissions for individual life cycle phases, at the inventory analysis stage of LCA offers a complementary approach to the traditional aggregate emission-based LCA approach. In a circular scenario, it helps to identify significant issues during different life cycle phases and the relevant environmental performance improvement opportunities through product, business model and supply chain design.
ARTICLE | doi:10.20944/preprints202012.0800.v1
Subject: Business, Economics And Management, Accounting And Taxation Keywords: organizational learning; circular economy; small and medium enterprises (SMEs); business model; supply chain; construction; Italy; Barrier and enabler
Online: 31 December 2020 (12:40:30 CET)
To contribute to small and medium enterprises (SMEs) sustainable transition into the circular economy, the study proposes the activation of organizational learning (OL) processes – denoted here as multi-level knowledge creation, transfer, and retention processes – as a key phase in introducing circular business models (CBMs) at SME and supply chain (SC) level. The research employs a mixed-method approach, using the focus group methodology to identify contextual elements impacting on CBM-related OL processes, and a survey-based evaluation to single out the most frequently used OL processes inside Italian construction SMEs. As main result, a CBM-oriented OL multi-level model offers a fine-grained understanding of contextual elements acting mutually as barriers and drivers for OL processes, as possible OL dynamics among them. The multi-level culture construct – composed of external stakeholders’, SC stakeholders’, and organizational culture – identify the key element to activate CBM-oriented OL processes. Main implications are related to the identification of cultural, structural, regulatory, and process contextual elements across the external, SC, and organizational levels, and their interrelation with applicable intraorganizational and interorganizational learning processes. The proposed model would contribute to an improved implementation of transitioning into the circular economy utilizing sustainable business models in the construction SMEs.
REVIEW | doi:10.20944/preprints202102.0447.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: circular economy; Covid-19; Voyant tools; environmental sustainability; social sustainability; economic sustainability; text mining
Online: 20 February 2021 (01:42:10 CET)
The emergence of the Covid-19 pandemic has created both negative and positive changes, including implementing the circular economy across the globe. This Systematic Review follows the PRISMA statement and employs the Text Mining (Voyant Tools) technique to visualize and analyze the impacts of the Covid-19 on three aspects of the circular economy: economic, social, and environmental. The research employs Latent Dirichlet Allocation (LDA) to identify five major topics: (1) Shortage of medical equipment but high medical waste during Covid-19 due to the high demand in healthcare; (2) The long term negative impacts of lockdown on economic and social activities because of Covid-19 pandemic; (3) The reports on impacts of Covid-19 pandemic on the manufacturing globally, and their coping strategies and new opportunities; (4) The impacts of international restriction on the tourism, trade, shipping, and aviation industry, causing billion-dollar losses; (5) The reduction of pollution with health environment improvements with example cases from China and EU. The research identifies current literature gaps in the circular economy and Covid- 19 topics and encourages the application of text mining tools into researching to stimulate the research process and assist in communicating with the public.
ARTICLE | doi:10.20944/preprints202307.1685.v1
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: Reverse logistic; Reverse Chain; WEEE; Industry 4.0 Technology; Simulation; Artificial intelligence; Eco-efficiency; Circular Economy
Online: 26 July 2023 (02:43:27 CEST)
The objective of this study was to apply simulation and computational intelligence techniques using artificial intelligence and genetic algorithm for economic and environmental optimization of the reverse network (manufacturers, waste managers and recyclers in São Paulo, Brazil) of waste electrical and electronic equipment (WEEE) to promote circular economy. For the economic evaluation, the reduction of: fuel, drivers, insurance, depreciation, maintenance and charges was considered and for the environmental evaluation, the environmental impact was measured in the abiotic, biotic, water, land, air and greenhouse gases compartments. It is concluded that the optimized structure of the WEEE reverse chain for São Paulo, Brazil reduced the number of collections, making the most of the cubage. It also generated economic and environmental gains, contributing to the strategic actions of the circular economy. Thus, the proposed simulation allows replication in organizational practice, mainly to meet the 2030 agenda on reducing the carbon footprint generated in transport in large cities. Thus, this study can guide companies on structuring the reverse WEEE chain in São Paulo, Brazil for economic and environmental optimization, a relevant aspect considering the exponential generation of WEEE, requiring the implementation of the national solid waste policy, and subsequently the signature of the electronics sector agreement in São Paulo.
ARTICLE | doi:10.20944/preprints201802.0024.v1
Subject: Environmental And Earth Sciences, Environmental Science Keywords: resource efficiency; zero waste; resource recovery from waste; low-carbon economy; circular economy infrastructure; clean growth; resource productivity; sustainable development goals; transdisciplinary research; participatory action research
Online: 5 February 2018 (03:27:02 CET)
The UK economy is overly reliant on unsustainable production and consumption practices, depleting finite resources at rates that will increase production costs, business risk and economic instability. This over-consumption produces emissions and waste that cause climate change and environmental degradation, impacting on the wellbeing of people in the UK and beyond. The Resource Recovery from Waste programme (RRfW) promotes a transition towards waste and resource management in a circular economy that restores the environment, creates societal benefits and promotes clean growth by engaging relevant actors in the transition process. RRfW collaborates with academia, government, and industry to co-produce a shared vision and approach to realise such a transition. Reflecting insights from RRfW’s government engagement, this article presents a positive outlook for changing the UK economy and society. It envisions a long-term future for waste and resource management that maximises the value of materials by circulating them in the economy for as long as possible. Four themes and an approach are proposed, including recommendations for regulatory instruments and a stable policy framework. It recommends further collaborative research to capitalise on opportunities for economic growth, innovation and resilient infrastructure whilst contributing to quality jobs and welfare in all four UK nations.
ARTICLE | doi:10.20944/preprints202307.0487.v1
Subject: Business, Economics And Management, Other Keywords: Circular Business Model; Digitalization; Circular transition; Digital transformation; equipment lifecycle extension.
Online: 7 July 2023 (10:37:37 CEST)
Digitalization technologies have been identified as enablers for the adoption of Circular Economy practices. The machinery value chain, addressed in this study, is affected by the introduction of digital technologies that enable real-time monitoring data on product condition and control optimization deploying predictive analytics techniques, as well as the offerings of circular-based services. Machinery lifetime extension can be digitally enabled on both old and new machines. The research objectives were to investigate how digital technologies enable the adoption of circular economy-based business models in manufacturing companies and provide an answer about i) what Life Cycle Extension Strategy is suitable for digital circular business model adoption and ii) how digitalization of machines enables manufacturing companies to innovate their business model. The correlation matrix is the tool developed from the proposed approach; it aims at supporting manufacturers in the very first contact with circular business models. In the context of the European RECLAIM project, two manufacturers apply the approach, proving its validity and wide applicability. The next steps are expected to introduce quantitative indicators to define thresholds for the steps toward circularity, without replacing the qualitative approach, as it guarantees the wide applicability of the approach in context that never considered circularity yet.
ARTICLE | doi:10.20944/preprints202312.0094.v1
Subject: Arts And Humanities, Architecture Keywords: maker spaces; circular cities; urban manufacturing; circular economy; case study; Leuven; Maakleerplek
Online: 1 December 2023 (16:33:15 CET)
The coordination of policy, makers and materials is critical to the success of circular city development. The network of maker activities in the city of Leuven is a flagship initiative that illustrates the mechanisms that support integrated circular urban production. This paper draws on the Pop-Machina project, funded by EC Horizon 2020, which identifies the links between the maker movement and the circular economy in seven European cities. The case study project in Leuven, confirmed as the most impactful amongst those studied in the Pop-Machina project, is examined to assess how local knowledge and policy measures, can provide a means of activating a circular maker ecology. Through desk research, spatial urban analysis and interviews with key stakeholders, this paper provides a critical narrative of the development, success factors and hurdles related to circular making processes in the city. It demonstrates how hybrid makers are supported by local, national, and international policy on the one hand, and by integration with the city’s community, educational and business groups on the other. It is this constellation of social, political, and spatial conditions that lies at the success of the project.
ARTICLE | doi:10.20944/preprints202310.1136.v1
Subject: Arts And Humanities, Architecture Keywords: maker spaces; circular cities; urban manufacturing; circular economy; reuse; repair; craft; fabricate; distribute.
Online: 18 October 2023 (08:30:16 CEST)
Maker spaces can contribute significantly to the circular economy of cities: they demonstrate not only the economic potential of inner loop circularity, but also provide tangible evidence of spatial and social integration of production into the urban context. This paper presents findings from a typological analysis of 326 maker spaces in seven European cities, with a focus on selected exemplar case studies to reveal design characteristics, principles and opportunities for circular city development. The research shows that circular economy principles of ‘reduce-reuse-recyle’ are aligned with maker spaces such as repair cafés, secondhand shops and fab labs. In the context of cities, circularity is revealed by a spatial tightening of resource cycles that close the loops of product life cycles. Furthermore, urban maker spaces demonstrate social engagement and a relationship to local production which inherently includes maintenance, repair, reuse, and redistribution. This paper defines five maker typologies, presents exemplars of each from different urban contexts and posits hybrid design strategies for the transition to circular maker cities. Through the adoption of these findings into urban planning policy it is possible accelerate circular urban production and close the sustainability gap between small scale local and large scale regional manufacturing.
ARTICLE | doi:10.20944/preprints202308.0681.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: recycle; circular economy; cryogenic removal
Online: 8 August 2023 (13:02:27 CEST)
Finished tanned leather are usually covered by a thin polymeric layer. This layer has the scope to change the morphological aspect of the last leather layer, as well as to improve the impermeabilization properties. Often, the finished product is refused by the final client and tanneries must restore significant quantity of materials. Therefore, it is very important to remove this finished polymeric layer, to recover the underneath tanned leather and to predispose it to a new finishing. The bonding between the polymeric film and leather is so strong that, today, only a blade shaving process can perform this separation at the expenses of also removing a layer of tanned leather and consequently reduce the leather thickness. Here, a novel separation method was developed, based on the significant difference in the dilation properties between the tanned hide and the polymeric film at low temperature. The use of cryogenic fluids, in particular the direct application of liquid nitrogen, can freeze the polymeric layer under the glass transition temperature and then inducing a brittle behaviour. The result is an easy separation without any alteration of the tanned leather layer. Thus, the process here developed, allows the reuse of the tanned leather towards a new life in the respect of the circular economy principles.
REVIEW | doi:10.20944/preprints201907.0108.v1
Subject: Medicine And Pharmacology, Obstetrics And Gynaecology Keywords: endometriosis; circular; microRNA; diagnosis; plasma
Online: 8 July 2019 (06:10:33 CEST)
Plasma microRNAs are considered to be potential diagnostic biomarkers for endometriosis. Increasing evidence has shown that a huge amount of miRNAs are abnormally expressed in endometriosis plasma and play irreplaceable roles in diagnosis. The aim of the our study was to identify the differential expression of circular miRNA by reviewing the PubMed, ScienceDirect, and Cochrane databases between normal women and women with endometriosis and analyzing the miRNA data downloaded from the GEO database. Because of the differential miRNA expression in this review, we evaluated the diagnostic values of the differentially expressed miRNAs, particularly during the menstrual phases. According to the cut-off criteria with |log 2 FC|>1.0 and P < 0.05, 36 differentially expressed miRNAs were identified, including 13 upregulated miRNAs and 23 downregulated miRNAs. We developed miR-155, miR-574, miR-23a, and miR-520d via a Venn diagram. Functional enrichment analysis considered that the target miRNAs might be involved in various pathways related to endometriosis, including neurotrophin, Hippo, oocyte meiosis, ubiquitin mediated proteolysis, HTLV-Infection, FoxO, and Rap1 signaling pathways. CTNNB1, MYC, and ES R1 of transcription factors were related to the differentially expressed miRNAs. In summary, our study suggested that a four-miRNA could be included as a prognostic marker in endometriosis.
ARTICLE | doi:10.20944/preprints202012.0370.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: Heme; Hemopexin; Circular dichroism; Recombinant hemopexin
Online: 15 December 2020 (10:24:49 CET)
Abstract: Plasma hemopexin (HPX) is the key antioxidant protein of the endogenous clearance pathway that limits the deleterious effects of heme released from hemoglobin and myoglobin. During intra-vascular hemolysis, heme partitioning to protein and lipid increases as the plasma concentration of HPX declines. Therefore, the development of HPX as a replacement therapy during high heme stress could be a relevant intervention for hemolytic disorders. A logical approach to enhance HPX yield involves recombinant production strategies from human cell lines. The present study focuses on a biophysical assessment of heme binding to recombinant human HPX (rhHPX) produced in the Expi293FTM (HEK293) cell system. In this report, we examine rhHPX in comparison with plasma HPX using a systematic analysis of protein structural and functional characteristics related to heme binding. Analysis of rhHPX by UV/Vis absorption spectroscopy, circular dichroism (CD), SEC-HPLC and catalase-like activity demonstrated a similarity to HPX fractionated from plasma. In particular, the titration of HPX apo-protein(s) with heme was performed for the first time using a wide range of heme concentrations to model HPX-heme interactions to approximate physiological conditions (from extremely low to more than 2-fold heme excess). The CD titration data showed an induced bisignate CD Soret band pattern typical for plasma and rhHPX versions at low heme-to-protein molar ratios and demonstrated that further titration is dependent on the amount of protein-bound heme to the extent that the arising opposite CD couplet results in a complete inversion of the observed CD pattern. The data generated in this study suggests more than one binding site in both plasma and rhHPX. Further, our study provides a useful analytical platform for detailed characterization of HPX-heme interactions and potentially, novel HPX fusion constructs.
REVIEW | doi:10.20944/preprints202004.0190.v1
Subject: Computer Science And Mathematics, Algebra And Number Theory Keywords: circular functions; hyperbolic functions; exponential functions
Online: 12 April 2020 (09:21:08 CEST)
In this paper, we provide alternative proofs to some results proposed in the article "New inequalities involving circular, inverse circular, hyperbolic, inverse hyperbolic and exponential functions" authored by Yogesh J. Bagul.
ARTICLE | doi:10.20944/preprints201805.0060.v1
Subject: Engineering, Civil Engineering Keywords: concrete; slag; valorization; cement; circular economy
Online: 3 May 2018 (09:00:22 CEST)
Concrete consumption greatly exceeds the use of any other material in engineering. This is due to its good properties as construction material and the availability of its components. Nevertheless, the present worldwide construction increase and the high-energy consumption for cement production means a high environmental impact. On the other hand, one of the main problem in iron and steel industry is waste generation and by-products that must be properly processed or reused to promote the environmental sustainability. One of these by-products are blast furnace slag. Cement substitution by slag strategy achieves two goals, raw materials consumption reduction and waste management. In the present work, four different concrete mixtures are evaluated. 25% cement is substituted by different blast furnace slag. Tests are made to evaluate the advantages and drawbacks of each mixture. Depending on the origin, characteristics and treatment of the slag, concrete properties change. Certain mixtures provide proper concrete properties. Stainless steel slag produces a fluent mortar that reduces the water consumption whit a slight mechanical strength loss. Mixture with electric arc slag furnace properties are better to the reference concrete (without slag) when slag is treated similarly to the cement.
ARTICLE | doi:10.20944/preprints202310.2012.v1
Subject: Biology And Life Sciences, Forestry Keywords: upcycling; particleboard; plywood; dust; circular economy; filler
Online: 31 October 2023 (09:07:09 CET)
Due to its size, wood dust often plays the role of a raw material used as a source of energy. However, it is nevertheless an unavoidable byproduct generated during the milling of wood or wood-based composites. The research presented here is focused on the selected properties of 3-layer plywood, produced with the utilization of dust from the milling of three-layer particleboard as a filler in the bonding mass. Four types of filler were used in the study: commercial rye flour, wood dust naturally occurring in the composition of particles used industrially for particleboard production, wood dust from the first batch of shredded particleboard, and dust from the second round of milled particleboard. In the context of this investigation, the highest modulus of elasticity (MOE) values were observed in reference samples. Conversely, for samples featuring filler material from the initial milling process, there were no substantial differences in filler content. Notably, in samples where the filler was sourced from the secondary milling of particleboard, the modulus of elasticity exhibited an upward trend in conjunction with increasing filler content. A similar trend was observed in samples utilizing the naturally occurring dust. Meanwhile, the modulus of rupture (MOR) decreased with an elevated degree of milling, though it displayed a slight increase as the filler content increased. With regard to shear strength testing, the most favorable outcomes were achieved in samples incorporating filler material from the initial milling of particleboard. The thickness swelling of the plywood reached its peak in variants utilizing filler material from both the initial and secondary milling of particleboards. In contrast, water absorption testing exhibited a more pronounced response in the newly introduced variants, although samples incorporating filler from the initial and secondary milling processes eventually yielded results akin to the reference sample, with the naturally occurring dust displaying higher water absorption values. In terms of density profiles, the highest density values were observed in samples utilizing rye flour as the filler material. A similar density profile was observed in samples with 5 parts of wood flour as filler, although the density of the adhesive was slightly lower in these cases. An increase in the quantity of wooden filler material resulted in a commensurate increase in plywood thickness. The research confirms the possibility of using the aforementioned dust as an alternative to conventional fillers in plywood technology. It also raises the question of how to effectively remove glue residues from wood-based composite dust, which would enhance their absorption properties.
ARTICLE | doi:10.20944/preprints202310.1761.v1
Subject: Environmental And Earth Sciences, Sustainable Science And Technology Keywords: reused wood; building construction; architecture; circular construction
Online: 27 October 2023 (06:52:16 CEST)
This study explores the perspectives and practices of architects regarding the reuse of wood in construction across five South-Central European countries: Slovenia, Serbia, North Macedonia, Bosnia and Herzegovina (BiH), and Montenegro. Based on a survey of architectural professionals, the research explores their attitudes, challenges, and motivations for using reclaimed wood, with a focus on circular construction principles. Key findings reveal unanimous agreement among re-spondents that both their profession and government entities inadequately support or promote wood reuse within the context of circular construction. While architects value reclaimed wood, there are country-specific variations. Environmental benefits, unique aesthetics, historical value, and sustainability are cited as primary motivators for reclaimed wood use. Additionally, re-spondents emphasize the ecological aspect as the most important consideration in wood product reuse, followed by economic and technological factors. Common concerns revolve around the long-term quality and maintenance of wood products. This research provides insights into the challenges and opportunities surrounding reclaimed wood use in South-Central Europe, high-lighting the need for support mechanisms and increased awareness to advance circular construc-tion practices in the region. These findings can have implications for architects and investors by identifying market opportunities, promoting eco-friendly practices, and providing valuable in-sights for future building designs with a focus on reclaimed wood elements within circular con-struction.
REVIEW | doi:10.20944/preprints202310.0210.v2
Subject: Chemistry And Materials Science, Biomaterials Keywords: acerola; acerola waste; circular economy; nutraceutical; biopolymers
Online: 17 October 2023 (08:06:24 CEST)
Acerola (Malpighia spp.) is a tropical plant genus of shrubs and trees whose fruit is rich in nutrients and bioactive compounds. However, its production generates significant waste that could pose an environmental issue. This review aims to summarize recent research on the potential uses of acerola wastes, including the extraction of bioactive compounds such as polyphenols, carotenoids, and pectins, as well as the development of materials such as nanomaterials, chitosan, and biofuels. Additionally, the paper discusses the potential medical applications of acerola wastes, such as wound healing, antioxidant, and anticancer effects. Finally, the paper explores the challenges and opportunities of using acerola waste as a sustainable source of raw materials and energy. The findings suggest that acerola waste could be a valuable resource for developing high-value products and promoting sustainable production practices in the fruit industry.
ARTICLE | doi:10.20944/preprints202103.0326.v2
Subject: Physical Sciences, Acoustics Keywords: circular torus; deformation; vibration; Gauss curvature; Maple
Online: 25 January 2022 (10:04:29 CET)
The formulation used by most of the studies on an elastic torus are either Reissner mixed formulation or Novozhilov's complex-form one, however, for vibration and some displacement boundary related problem of a torus, those formulations face a great challenge. It is highly demanded to have a displacement-type formulation for the torus. In this paper, I will carry on my previous work [ B.H. Sun, Closed-form solution of axisymmetric slender elastic toroidal shells. J. of Engineering Mechanics, 136 (2010) 1281-1288.], and with the help of my own maple code, I am able to simulate some typical problems and free vibration of the torus. The numerical results are verified by both finite element analysis and H. Reissner's formulation. My investigations show that both deformation and stress response of an elastic torus are sensitive to the radius ratio, and suggest that the analysis of a torus should be done by using the bending theory of a shell, and also reveal that the inner torus is stronger than outer torus due to the property of their Gaussian curvature. Regarding the free vibration of a torus, our analysis indicates that both initial in u and w direction must be included otherwise will cause big errors in eigenfrequency. One of the most intestine discovery is that the crowns of a torus are the turning point of the Gaussian curvature at the crown where the mechanics' response of inner and outer torus is almost separated.
ARTICLE | doi:10.20944/preprints202107.0139.v1
Subject: Business, Economics And Management, Accounting And Taxation Keywords: circularity; waste streams; circular approaches; regression equation
Online: 6 July 2021 (11:40:19 CEST)
In this paper, the authors identified key elements important for circularity: (1) Background: The primary goal of circularity is to eliminate waste and to prove the constant use of resources. In the paper, we classify studies according to circular approaches. The authors identified main elements and classified them into categories important for circularity, starting with the managing and reducing waste and the recovery of resources; and ending with the circularity of material, and general circularity-related topics and presented scientific works dedicated to each of the above-mentioned categories. The authors analyzed several core elements from the first category aiming to investigate and connect different waste streams and provided a regression model; (2) Methods: The authors used a dynamic regression model to identify relationships among variables and selected the ones, which has an impact on the increase of biowaste. The research was delivered for the 27 European Union countries during the period between 2020 and 2019; (3) Conclusions: The authors indicated that the recycling rate of wasted electrical equipment in the previous year has an impact on the increase of recycling biowaste next year. This is explained as non-metallic spare parts of electronic equipment are used as biowaste for fuel production. And the separation process of the composites of electric equipment takes some time, on average the effect is evident in one year period.
REVIEW | doi:10.20944/preprints201810.0708.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: circular visualization; circos; genomics; next-generation sequencing
Online: 30 October 2018 (07:06:35 CET)
After human genome sequencing and rapid changes in genome sequencing methods, we have entered in the era of rapidly accumulating genome-sequencing data. This has poses development of several types of methods for representing results of genome sequencing data. Circular genome visualizations tools are also critical in this area as they provide rapid interpretation and simple visualization of overall data. In the last 15 years, we have seen rapid changes in circular visualization tools after the development of the circos tool with 1–2 tools published per year. Herein we have summarized and revisited all these tools until the third quarter of 2018.
ARTICLE | doi:10.20944/preprints202310.0317.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: Kunkur fines; blended cement; mixture design; circular economy
Online: 6 October 2023 (06:18:39 CEST)
Ternary blended cements such as limestone calcined clay cement (LC3) represent a strategic binder type for the mitigation of environmental impact associated with cement production and are estimated to reduce CO2 emissions by about 40% compared to ordinary Portland cement (OPC). In this paper we explore the possibility of producing such ternary blends by utilizing secondary raw materials that may be locally available. Specifically, the primary limestone that is commonly used in LC3 is here substituted by quarry dust obtained by sourcing of “kunkur”, a carbonate-rich sedimentary rock (also known as caliche) that can be locally utilized for the production of ordinary OPC clinker. To optimize the blending proportions of ternary cements consisting of OPC, calcined clay and kunkur fines, a Design of Experiment (DoE) approach was implemented, with the further goal of exploring the possibility of reducing the amount of the OPC fraction to values lower than 50%. The properties of the formulated blends were assessed by a combination of techniques that comprise mechanical strength testing, XRD time-dependent quantitative phase analysis, SEM-EDS microstructural and microchemical analysis. The results suggest that ternary blended cements based on kunkur fines form hydration products, such as hemicarboaluminates, which are also observed in LC3. This shows that such a waste material can potentially be used in sustainable cement blends, however, the presence of kaolinite in the kunkur fines seems to affect the development of strength when compared to both OPC and conventional LC3.
ARTICLE | doi:10.20944/preprints202305.2243.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: Activated carbon regeneration; pesticide removal; reuse; circular economy
Online: 31 May 2023 (12:00:20 CEST)
This paper describes the influence of the regeneration treatments on 4-chloro-2-methyl-phenoxyacetic acid (MCPA)-loaded activated carbons (ACs) on adsorption-desorption cycles with two commercial ACs, Merck and Norit 1240 X ( Norit 1240 X was used in a granular and powder form). The ACs were saturated with MCPA and then submitted to four regeneration cycles, by washing with ethanol, NaOH solutions and washed with NaOH solutions followed by a thermal treatment. The ACs regenerated with ethanol showed a better performance concerning the successive adsorption-desorption cycles. On the first cycle, the MCPA desorbed, from washing with ethanol, from all ACs was higher than 99%. After a fourth adsorption-desorption cycle, washing regeneration combined with thermal treatment allowed excellent regeneration results. The amount of MCPA adsorbed on Norit 1240 X AC was higher than the amount adsorbed in the first cycle. MCPA adsorption kinetic data were analyzed by applying pseudo-first-order, pseudo-second-order, and Weber-Morris models. The pseudo-second-order fit better fit to the data and the Weber-Morris representation allows confirming that on Norit 1240 X, in a granular form, the pore diffusion was the limiting factor concerning the MCPA adsorption.
REVIEW | doi:10.20944/preprints202304.1274.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: grain waste; grain by-products; valorization; circular economy
Online: 30 April 2023 (11:05:57 CEST)
In an increasingly resource-constrained era, the utilization approach of waste and by-products from grain processing, is attractive widely, considering both nutritive value and economic aspects and move towards more sustainable food systems. Following the fundamentals of a circular economy, the need of the hour lies in its effective utilization as a grain waste and by-products conversion into value-added products in food industry. The aim of this study is twofold: 1. Understanding the progress of grain waste and by-products to valorization in human nutrition, using bibliometrics; different literature databases namely Google Scholar, Web of Science and Elsevier Scopus have been evaluated for their merits and values; 2. Exploration of knowledge-based strategies, by reviewing the literature concerning the possible use of grain waste and by-products for food processing industry, reducing burden on virgin raw materials. The review allowed to unlock the latest-advances of upcycling side streams and waste from grain processing industry.
REVIEW | doi:10.20944/preprints202301.0070.v1
Subject: Environmental And Earth Sciences, Water Science And Technology Keywords: Circular Economy; Water; Wastewater; Resource Use; Latin America
Online: 4 January 2023 (06:39:53 CET)
Circular Economy (CE) is noted as an emerging tool or framework to support sustainable production and consumption agenda. In addition, CE is aiming to be a trigger for redefining economic growth pathways to be sustainable, inclusive, and sensitive to ecological and environmental agendas and to focus its operational standards on co-creating societal benefits. Concerning the guiding principles and the standards of practice applied to implement and scale circular economy, this study will provide an overview of the water sector-specific circularity roadmaps and strategies in the Latin American Region. By using a semi-systematic review, document analysis, and qualitative assessment approach, we highlight framings and operational pathways, gaps, and needs within existing practices of circularity in the water sector. The results provide an overview of CE pathways at the national level of selected countries in LAR iterating those nations reflect various levels of advancement (low to high) with CE-focused innovations and policy support structures specific to the water and wastewater sectors. Towards the closing, the study is pointing to the ‘call for action’ to integrate outstanding advances and innovations in the circular economy within sectoral mandates for water and wastewater management, making an argument that circularity in the water sector could serve as an accelerator toward implementing the agenda outlined in Sustainable Development Goals (SDGs) and in particular for SDG 6 (water security for all).
ARTICLE | doi:10.20944/preprints202207.0162.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Circular RNA; Cutaneous Melanoma; Immunotherapy; metastasis; LncRNA; ecRNA
Online: 11 July 2022 (14:14:53 CEST)
Cutaneous Melanoma (CM) is the most lethal form of skin cancer if it becomes metastatic, where treatment options and survival chances decrease dramatically. Immunotherapy treatments based on the immunologic checkpoint inhibitors (PD-1 and CTLA4) constituted a main breakthrough in the treatment of metastatic CM, particularly in the long-term benefit. However, several molecular pathways are responsible for the failure of this strategy in about 50-70% of CM patients. Some Long Non-coding RNAs (lncRNAs), and circular RNAs (circRNA) are implicated in triggering pro- and antitumorigenic responses to various cancer treatments. The relationship between lncRNA, circRNA and Immune Checkpoint Blockade (ICB) immunotherapy is not extensively explored in cutaneous metastatic melanoma (CMM). The aim of this study is to evaluate the potential role of both circRNA and lncRNA as a predictive immunotherapy biomarker in CMM. RNA-seq from 12 FFPE samples from the metastatic biopsy of metastatic melanoma patients treated with Nivolumab were analyzed. Our findings indicate that specific lncRNA and circRNA are involved in regulatory networks of the immune response against metastatic melanoma under treatment with nivolumab. Moreover, we have established a risk score that allows the prediction of Overall survival (OS) and Progression-free survival (PFS) of CMM patients with high accuracy. This proof of principle work provides a possible insight on the function of ceRNA, contributing to decipher the complex molecular mechanism of ICB cancer treatment response.
ARTICLE | doi:10.20944/preprints202112.0297.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: Achiral plasmonic structure; Circular dichroism; Glucose; ellipsometry method.
Online: 20 December 2021 (09:44:59 CET)
Various efforts have been made to detect minimum value of glucose in any medium like water or body buffer solutions with high-sensitivity, accurate, and low-cost sensors in order to enhance life style. Therefore, the present study was done to investigate reliability of two-dimensional plasmonic structure by circular dichroism (CD) and ellipsometry tools in different concentrations of glucose. Our results confirmed a dependency of the CD signal on glucose concentrations and also a very good sensitivity based on the phase difference between each polarization in ellipsometry parameters with the help of an achiral plasmonic structure.
ARTICLE | doi:10.20944/preprints202102.0620.v1
Subject: Chemistry And Materials Science, Food Chemistry Keywords: IntegroPectin, naringin, eriocitrin, citrus, flavonoids, pectin, circular economy
Online: 26 February 2021 (13:47:16 CET)
Following the analysis of terpenes present in new lemon and grapefruit “IntegroPectin” pectins obtained via the hydrodynamic cavitation of industrial lemon and grapefruit processing waste, the HPLC-MS analysis of the flavonoid compounds reveals the presence of eriocitrin, naringin, hesperidin and kaempferol typical of the respective citrus fruits. The pectic fibers rich in rhamnogalacturonan-I “hairy” regions act as chemical sponges adsorbing and concentrating at their outer surface highly bioactive citrus flavonoids and terpenes. These findings, together with the unique molecular structure of these new whole citrus pectins, provide preliminary insight into the broad-scope and powerful biological activity of these biomaterials. Numerous new biomedical applications beyond prevention and treatment of microbial infections and neurodegenerative disease are anticipated.
ARTICLE | doi:10.20944/preprints202011.0190.v1
Subject: Engineering, Automotive Engineering Keywords: zero waste; plastic waste; circular economy; recycling performance
Online: 4 November 2020 (10:45:14 CET)
Despite the increase in popularity of Zero Waste (ZW) concept, the successful implementation of this concept in waste management is still facing many challenges. The plastic recycling rate in Australia is currently only about 9.4%, which could leave up to 90.6% of plastic consumption being sent to landfills. The state of Victoria (in Australia) has proposed an ambitious plan to upgrade its waste and recycling system and to divert about 80% of waste from landfills by 2030. The aim of this research is to study Victoria’s current waste management plan and to develop a simulation model to assess the feasibility of it achieving zero plastic waste by 2035. In this direction, a fundamental knowledge of global ZW implementation needs to be acquired in order to understand the challenges, obstacles, and uncertainties in achieving ZW target. A simulation model is established using a method called double baselines. This method was developed as an improvisation to address the limitation of data availability for the model development. The model will run on 4 scenarios including one from Victoria’s current plan. Outcomes from the model are produced in comparative charts covering 6 key considerations including the rates of plastic consumption, waste to landfill, diversion, recycling, relative accumulative cost and effort. The findings of this study pointed out that Victoria’s current plan are feasible for its goal and presented with opportunities for improvement especially towards zero plastic waste. Besides, study results also reveal that the Victoria’s current plan to achieve 80% diversion rate by 2030 is possible but the zero plastic waste target by 2035 is less likely to happen.
ARTICLE | doi:10.20944/preprints202006.0296.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: antennas; wideband antennas; probe-fed antennas; circular patch
Online: 24 June 2020 (09:53:44 CEST)
In this paper, a new probe-fed wideband antenna with a circular patch and a coupled stacked ring is proposed. This antenna can be implemented by using suspended microstrip technique with total thickness of about 0.09 of center frequency wavelength. By using a novel feeding technique, in this antenna about 40 % reduction in area compared to similar works can be achieved. The obtained bandwidth in this antenna according to simulation results satisfying VSWR<2 is about 27.5 % from 5 to 6.6 GHz using two resonant frequencies. Also a comprehensive theoretical and parametric study is done in order to facilitate its designing in various frequency bands.
REVIEW | doi:10.20944/preprints202311.0334.v1
Subject: Engineering, Civil Engineering Keywords: railway; track; sustainability; materials; maintenance; monitoring; circular economy; LCA
Online: 7 November 2023 (02:49:46 CET)
Rail, as the cleanest and greenest high-volume transport, has a central role in the decarbonizing, and it is expected to become the backbone of future mobility in the world. It is worthy to highlight that rail generates the lowest CO2 emissions and energy consumption in operation with respect to the other transportation modes but during construction and maintenance phases CO2 emission, energy consumption and other environmental impacts are significant and need to be carefully assessed and properly mitigated. This paper, based on an extensive literature review, provides a comprehensive framework of trends and challenge in railway sustainability. Attention is focused on track and related materials, maintenance strategies, and methods of assessment of the sustainability. Results show that improvement of materials and practices used in construction and appropriate strategies in maintenance, supported by effective monitoring of the state of the track, can reduce the negative effects on the environment and society and contributes to make this transportation mode greener. Proper methods for the assessment of the sustainability, (LCA, Circularity Index) help to quantify the potential of environmental enhancement of different solutions and constitute effective and indispensable tools in the decision-making process.
REVIEW | doi:10.20944/preprints202308.1920.v1
Subject: Engineering, Chemical Engineering Keywords: Integrated Management; Industrial Wastewater; Food Sector; sustainable; circular economy
Online: 29 August 2023 (03:55:07 CEST)
The physicochemical treatment/recovery techniques, including precipitation, membrane technology, solvent extraction, foam fractionation, adsorption, and aqueous two-phase systems, will be reviewed. The bio-treatment processes, based on microorganisms and/or enzymes consuming nutrients available in food-processing wastewater as low-cost substrates to produce valuable products, will be discussed in detail, including the production of microalga biomass in wastewater treatment systems. Finally, future research direction will be proposed to integrate the circular economy and develop integrated food processing wastewater management systems.
REVIEW | doi:10.20944/preprints202307.1988.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: Macroalgae; Microalgae; Yeast; Biomass conversion; Climate change; Circular bioeconomy
Online: 28 July 2023 (13:36:48 CEST)
: Seaweeds are among the most important biomass feedstocks for the production of third generation biofuels. They are also efficient in carbon sequestration during growth, and produce a variety of high value chemicals. Given these characteristics together with the relatively high carbohydrate content, seaweeds have been discussed as an ideal means for CO2 capture and biofuel production. Though third generation biofuels have emerged as some of the best alternatives to fossil fuels, there is currently no large-scale production or mainstream use of such liquid fuels due to the many technical challenges and high production costs. The present study describes the concept of coastal marine biorefineries as the most cost-effective and sustainable approach for biofuel production from sea-weeds as well as atmospheric carbon capture and storage (CCS). The suggested refinery system makes use of marine resources, namely seawater, seaweed, and marine microorganisms. Firstly, extensive screening of the current literature was performed to determine which technologies would enable the emergence of such a novel biorefinery system and its merits over conventional refineries. Secondly, the study investigates various scenarios assessing the potential of seaweeds as a means of carbon sequestration. We demonstrate that the removal of 100 Gigatons of excess CO2 using seaweed farms can be achieved in around 4 months to less than 12 years depending on the area under cultivation and the seaweed species. The total bioethanol that could be generated from the harvested biomass is around 8 trillion litres. In addition, high-value chemicals (HVC) that could potentially be recovered from the process represent a considerable op-portunity with multi-billion-dollar commercial value. Overall, coastal marine biorefineries have strong potential for a sustainable green economy and rep-resent a rapid approach for climate change mitigation.
ARTICLE | doi:10.20944/preprints202306.0104.v1
Subject: Environmental And Earth Sciences, Sustainable Science And Technology Keywords: Circular Economy; Life Cycle Assessment; Carbon Footprint; Information Systems
Online: 1 June 2023 (15:22:06 CEST)
Abstract: The need to rapidly reduce GHG has accelerated the adoption of circular models of production. However, this has proved to be a challenging task for SMEs, who lack the financial, organizational and informational capabilities to implement circular business models. In this context, calculating the carbon footprint (CF) of their products could provide the basis for assessing the different circular economy (CE) practices. The aim of this study is to present a CF calculation tool that can be used to calculate the CF of SMEs. The design of the tool was based on the Life Cycle Assessment (LCA) methodology, taking into account the various barriers that SMEs face in adopting CE practices. The tool was tested in a small cheese factory in northern Greece. The pro-duction process was mapped, a GHG inventory was created and the total emissions related to the production of a specific product was estimated. The final aim is to test this tool at a large scale.
ARTICLE | doi:10.20944/preprints202305.1607.v1
Subject: Chemistry And Materials Science, Metals, Alloys And Metallurgy Keywords: Circular flow configuration; Multi-field coupling; Cementation; Cadmium; Kinetic
Online: 23 May 2023 (08:02:11 CEST)
In this work, an novel flow-electric field coupling configuration for enhanced Zn-Cd cementation was designed and utilized. A series of tests were conducted to explore the optimization of Zn-Cd cementation process and its mechanism.Firstly, the various characterisations of the cadmium sponge at different locations in the device were compared and it was concluded that the purity of the cadmium sponge was optimal from the anode surface. The generation and stripping of cadmium sponge was revealed for the first time by cross-sectional electron microscopy. The four stages of the apparent reaction in the system were analysed in relation to the pH, cadmium concentration and cadmium sponge flaking at each flow rate. It was proved that the separation of cadmium sponge mainly occurred in the third phase. Secondly, by comparing the morphology and specific surface area of cadmium sheep at different flow rates, the optimum flow field velocity was identified as 30 ml/s. Six flow field configurations were compared and preferred. The results demonstrate that the LCAH modulation results in a more sparse structure of the cadmium sponge, which is more easily exfoliated from the zinc anode surface by fluid impact. This was considered to be the most beneficial flow field configuration for improving the cadmium cementation rate and reducing the cost of the reaction. Further, the reaction steps of the system were analysed. The diffusion process under different flow field configurations was confirmed by calculations to follow first order kinetics. The diffusion coefficient of LACH proved to be the highest in the comparative tests and this result was also supported by the apparent experimental results.
ARTICLE | doi:10.20944/preprints202305.0514.v1
Subject: Engineering, Telecommunications Keywords: Circular Polarization; CubeSat; Multi-band Antenna; Antenna on Structure
Online: 8 May 2023 (10:26:45 CEST)
This article presents a wide-band antenna designed for the Cube Satellite (CubeSat). Based on a quadrifilar structure, the antenna provides circular polarization radiation, which is suitable for satellite communication. Moreover, the antenna is designed and fabricated using two 1.6 mm thickness FR4-Epoxy boards that connect together by the metal pins. In order to improve the robustness, a ceramic spacer is placed in the centerboard, and four screws at the corners are added to fix the antenna with the CubeSat structure. These additional parts reduce antenna damage caused by vibrations in the launch vehicle lift-off stage. The proposal has a dimension of 77mm x 77mm x 10mm and covers the LoRa frequency bands of 868 MHz, 915 MHz, and 923 MHz. According to the measurements in an anechoic chamber, antenna gains are obtained with the values of 2.3 dBiC and 1.1 dBiC for the 870 MHz and 920 MHz, respectively. Finally, the antenna is integrated into a 3U CubeSat that was launched by a Soyuz launch vehicle. The terrestrial-to-space communication link was measured, and the antenna performance was confirmed in the real-life scenario.
ARTICLE | doi:10.20944/preprints202301.0062.v1
Subject: Engineering, Civil Engineering Keywords: stress distribution; model sand; circular footing; finite element analysis
Online: 4 January 2023 (03:54:30 CET)
This paper presents the experimental and numerical studies of the vertical stress distribution beneath the centerline of circular footings resting on the sand. Vertical stress values due to circular load in medium-dense sand were measured using soil stress transducers. Reduced-scale laboratory model tests were carried out in a square-shaped test box and vertical stresses were measured at the centerline of the circular footing at different depths of the sand. In order to determine the effect of footing width on vertical stress distribution, laboratory experiments were performed on circular footings of different diameters. In addition, a series of finite element analyses was carried out on the test model to validate the findings of the experimental study. In the numerical analysis, the sand was modeled as a non-linear elastoplastic material. The analyses were performed using the finite element method with two-dimensional axisymmetric and three-dimensional conditions. The results obtained from laboratory model tests and numerical analysis were compared with the vertical stress values obtained from the theoretical solution in the literature. Vertical stress distribution in horizontal planes at any depth from the footing base shows the same characteristic form in all methods. However, some differences were observed between experimental, numerical, and theoretical results and discussed.
ARTICLE | doi:10.20944/preprints202210.0088.v1
Subject: Engineering, Civil Engineering Keywords: Circular City Index; Urban Regeneration; Energy and Ecological Transition
Online: 8 October 2022 (03:06:49 CEST)
Cities consume over 75% of natural resources, produce over 50% of global waste and emit 60 - 80% of greenhouse gases. The scenario that by 2050 two thirds of the world population will live in cities, highlights how cities are still responsible of the growing consumption characterized by linear economy processes, with the production of various types of waste. In this unsustainable framework, the Circular Economy offers the opportunity to shape the urban system by means of rethinking the possibility to produce and use goods and services exploring new ways to ensure long-term prosperity. The Circular City paradigm contains in fact all the principles of the Circular Economy: recovery, recycling and sharing. In particular, Circular City also introduces actions related to the development of renewable energy communities, use of green materials, CO2 absorption approaches and Proximity Cities. The aim of this work is to develop a methodology to build a composite index (Circular City Index) capable of measuring the degree of implementation of urban policies that enable the territory to initiate an ecological transition of public assets. The city of Cagliari (Sardinia, Italy) represents the case study to apply circular urban policies in public properties, for civil and military use.
REVIEW | doi:10.20944/preprints202208.0530.v1
Subject: Engineering, Civil Engineering Keywords: Resource recovery; circular economy; food waste; anaerobic co-digestion
Online: 31 August 2022 (03:10:30 CEST)
The emergence of the circular economy, and the evolving paradigms in the treatment and management of wastewater, have opened up an opportunity for co-digestion of organic waste (i.e., food waste) with sewage sludges to enhance resource recovery at wastewater treatment plants (WWTPs). This paper reviewed the potential for anaerobic co-digestion of food waste and sewage sludges, as well as alternative sustainable food waste handling systems in South Africa. The promotion of the circular economy by the latest national solid waste management strategy and the ongoing efforts for resource recovery by the wastewater sector suggests that anaerobic co-digestion of food waste and sewage sludge is possible in South Africa. Furthermore, an integrated food waste disposer (FWD) system was identified as a sustainable alternative for food waste handling. To formulate a roadmap for future food waste and sewage sludge co-digestion implementation, a multi-disciplinary investigation is required to bridge the literature gap.
ARTICLE | doi:10.20944/preprints202201.0100.v1
Subject: Engineering, Mechanical Engineering Keywords: circular torus; finite element method; analytical solution; Gaussian curvature
Online: 10 January 2022 (11:27:25 CET)
The Gol'denveizer problem of a torus was studied analytically by Audoly and Pomeau (2002), and the accuracy of the Audoly and Pomeau linear law was confirmed numerically by Sun (2021). However, the law does not include the major radius R of the torus. To find the influence of the major radius, we used finite element numerical simulation to simulate different cases, and we propose a modified Audoly and Pomeau linear law for vertical deformation, which includes R. A linear law of horizontal deformation is presented as well. Our studies show that the Audoly and Pomeau linear law has high accuracy. With modified vertical and horizontal deformation, a displacement-compatible relation between them is formulated.
ARTICLE | doi:10.20944/preprints202102.0142.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: Anaerobic digestion; circular economy; biogas; fish waste; anchovy; limonene
Online: 4 February 2021 (15:03:46 CET)
Anchovies are amid the largest fish catch worldwide. The anchovy fillet industry generates a huge amount of biowaste (e.g. fish heads, bones, tails) that can be used for the extraction of several potentially valuable bioproducts including omega-3 lipids. Following the extraction of valued fish oil rich in omega-3, vitamin D3 and zeaxanthin from anchovy fillet leftovers using biobased limonene in a fully circular process, the solid residue was used as starting substrate for the production of biogas by anaerobic digestion. The results first reported in this study demonstrate good potential energy recovery of the anchovy sludge of about 280 mLCH4∙gVS-1. Due to unbalanced C/N ratio typical of marine biowaste, co-digestion with a carbon rich substrate is recommended.
ARTICLE | doi:10.20944/preprints201808.0540.v1
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: circular economy; remanufacturing; fuel cells; data-driven; systems dynamics
Online: 31 August 2018 (05:31:03 CEST)
Remanufacturing is a viable option to extend the useful life of an end-of-use product or its parts, ensuring sustainable competitive advantages under the current global economic climate. Challenges typical to remanufacturing still persist, despite its many benefits. According to the European Remanufacturing Network a key challenge is lack of accurate, timely and consistent product knowledge as highlighted in a 2015 survey of 188 European remanufacturers. With more data being produced by electric and hybrid vehicles, this adds to the information complexity challenge already experienced in remanufacturing. Therefore, it is difficult to implement real-time and accurate remanufacturing for the shop floor; there are no papers that focus on this within an electric and hybrid vehicle environment. To address this problem this paper attempts to (1) identify the required parameters/ variables needed for fuel cell remanufacturing by means of interviews (2) rank the variables by Pareto analysis (3) develop a casual loop diagram for the identified parameters/ variables to visualise its impact on remanufacturing (4) model a simple stock and flow diagram to simulate and understand data and information-driven schemes in remanufacturing.
ARTICLE | doi:10.20944/preprints201708.0108.v1
Subject: Physical Sciences, Astronomy And Astrophysics Keywords: AGN; jets; polarisation; linear; circular; radio; polarised radiative transfer
Online: 31 August 2017 (15:25:30 CEST)
The polarised emission from AGN jets carries information about the physical conditions at the emitting plasma elements while its temporal evolution probes the physical processes that introduce variability and dynamically modify the local conditions. Here we present the analysis of multi-frequency radio linear and circular polarisation datasets with the aim to exactly quantify the conditions in blazar jets. Our analysis includes both the careful treatment of observational datasets and numerical modelling for the reproduction of synthetic polarisation curves that can be compared to the observed ones. In our approach the variability is attributed to traveling shocks. The emission from the cells of our jet model is computed with radiative transfer of all Stokes parameters. The model also accounts for Faraday effects which map the low-energy particle populations. We present two extreme cases in terms of the significance of Faraday conversion in the production of circular polarisation. As we show, in both regimes the model gives realistic reproduction of the observed emission.
ARTICLE | doi:10.20944/preprints202312.0435.v1
Subject: Political Science, Social Sciences Keywords: mineral resource; policymaking; critical mineral; input-output analysis; circular economy
Online: 7 December 2023 (03:05:51 CET)
The circular economy is based on maintaining a circular flow of resources. Policymakers face difficulties in balancing national security and circular economy aspects in the field of mineral resources policy. With a uniquely expanded input-output table, this study estimates the final destination of several critical minerals (lithium, cobalt, yttrium, lanthanum, cerium, neodymium and dysprosium) and base metals (iron, copper and aluminum) in the Japanese economy for 2015. Our model shows quite a good similarity between the estimated composition and the actual data of products. The results reveal a detailed distribution of critical minerals and indicate prioritized implementation for creating and maintaining a circular flow of critical minerals. Developed decision flow guidance provides a comprehensive approach to national security and circular economy aspects for policymakers. For further actions, inclusive indicator development is required for policymakers to support the determination of implementation possibilities from social and technological aspects.
ARTICLE | doi:10.20944/preprints202311.0052.v1
Subject: Physical Sciences, Condensed Matter Physics Keywords: skyrmion; circular ring nanotrack; skyrmion Hall effect; Dzyaloshinskii–Moriya interaction
Online: 1 November 2023 (09:22:05 CET)
As an outstanding information carrier, skyrmion is increasingly widely used in devices based on complex geometries. To achieve the skyrmion-based spintronic devices, a reasonable and feasible nanotrack is essential. In this paper, we conducted a study on the current-driven skyrmion movement in a circular-ring-shaped nanotrack. Our results suggest that the asymmetry of the inside and outside boundary of the circular ring changed the stable position of the skyrmion, causing it to move like the skyrmion Hall effect when driven by currents. Moreover, the asymmetric boundaries have advantages in enhancing or weakening the skyrmion Hall effect. Additionally, we also compared the skyrmion Hall effect from the asymmetric boundary of circular ring nanotracks with that from inhomogeneous DMI. It is found that the skyrmion Hall effect caused by the circular ring is significantly greater than that caused by the inhomogeneous DMI. These results contribute to our understanding of the skyrmion dynamics in confined geometries and offer an alternative method for controlling the skyrmion Hall effect of skyrmion-based devices.
ARTICLE | doi:10.20944/preprints202310.0500.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: circular polarization; mobile communications; slot antenna; base station; offset feeding
Online: 10 October 2023 (02:51:56 CEST)
In this paper, a circularly polarized broadband slot antenna is designed for base station applications. The antenna is built on a square-shaped FR4 Epoxy substrate that measures 60mm in length and 1mm in height with a relative permittivity of 4.4. The ground plane has a recessed slot, and the feeding mechanism employs an offset microstrip line. The slot enables circular polarization and optimal impedance matching, which are enhanced further by offset feeding and the addition of stubs to create a composite-shaped patch. With an impedance bandwidth of 106% (1.28 GHz-4.16 GHz) and an axial ratio bandwidth of 69% (1.71 GHz-3.51 GHz), the CP broadband slot antenna effectively covers popular mobile communication bands such as GSM 1800, GSM 1900, 3G/LTE 2100, 3G/LTE 2300, 4G/LTE 2500, and 2.4 GHz Wi-Fi bands. The maximum gain is simulated to be 3.5 dB.
REVIEW | doi:10.20944/preprints202307.1822.v1
Subject: Environmental And Earth Sciences, Waste Management And Disposal Keywords: Medicinal and aromatic plants; sustainability; circular economy; waste management; valorisation
Online: 27 July 2023 (09:13:06 CEST)
Due to the growing demand for Medicinal and Aromatic Plants (PAMs), environmental risks associated with overexploitation and inadequate waste management are increasing. Since MAPs residues have a notable potential to be valorised, the implementation of Circular Economy solutions can play a central role in transforming waste management problems into economic opportunities and in responding to the growing demand for MAPs. Circular economy is viewed as a solution for fostering a sustainable system planet and positively contributes to the economy and society. A systematic review was conducted aiming to identify potential applications for the valorisation of MAP, under a sustainable waste management and circular economy approach. A total number of 47 studies were analysed and it was verified that MAPs residues can be valorised for energy purposes, crop management and applications in chemical, food, pharmaceutical, cosmetic industries, among others. Despite the wide range of possible applications, to promote a progressive implementation of circular economy strategies by the industry, further investigation is needed regarding the development of more efficient techniques and technology to develop value-added products and the assessment of sustainable performance in empirical investigations, considering both economic and environmental indicators.
ARTICLE | doi:10.20944/preprints202305.1141.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: Phase shifter; Circular polarizer; High-power microwave (HPM); Waveguide component
Online: 16 May 2023 (09:38:27 CEST)
This paper presents a novel high-power rotary waveguide phase shifter based on circular polarizers specifically engineered for high-power microwave (HPM) applications. The phase shifter is capable of performing a precise 360° linear phase shift through rotation and consists of three parts: a linear polarized to left-handed circular polarized (LP-LHCP) mode converter, a left-handed to right-handed circular polarized (LH-RHCP) mode converter, and a linear polarized to right-handed circular polarized (LP-RHCP) mode converter. The paper analyzes the phase shifting principle, optimizes the three parts of the X-band rotary waveguide phase shifter, and conducts simulation studies on the entire phase shifter made of aluminum. The results show that the reflection is less than -20dB and the transmission efficiency is over 95% within 9.5GHz to 10.2GHz. The phase shift has a linear relationship with the rotation angle by a factor of two within this frequency range. Specifically, the phase shifter can achieve a linear phase shift of 360° when rotated from 0° to 180°, with a maximum deviation of less than 1.2°. Moreover, the power-handling capacity of the phase shifter in vacuum exceeds 242mW.
ARTICLE | doi:10.20944/preprints202304.0176.v1
Subject: Engineering, Telecommunications Keywords: Annular leaky-wave antenna; conical and broadside beams; circular polarization
Online: 11 April 2023 (03:13:27 CEST)
In order to properly cover different scenarios, radiation patterns of antennas should be accordingly adjusted before fabrication. However, most antennas are unable to provide both broadside beam and designable conical beam which are usually-used radiation patterns for radio coverage. In this paper, a planar Circular Polarized (CP) annular Leaky-Wave Antenna (LWA) with conical beam is proposed, which is realized on annular Substrate-Integrated Waveguide (SIW). Broadside beam or conical beam could be easily obtained by fabricating the LWA with modified structural parameters. The central operating band is 5.8 GHz. The LWA allows only the -1th spatial harmonic to radiate, while the fundamental wave and other spatial harmonics are suppressed in slow wave mode. In order to validate the design effectiveness, two examples for broadside beam and conical beam radiation are fabricated and measured. The measurement results show good agreement with the simulation results. The proposed LWA presents a promising radiation performance and is a good candidate for wireless communication applications.
ARTICLE | doi:10.20944/preprints202301.0352.v1
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: conformational chiralty; atropisomers; racemization; xray structure; circular dichroism; computa-tional
Online: 19 January 2023 (09:13:54 CET)
Dibenzocycloctynes have emerged as a promising scaffold for bioorthogonal ligation. An important structural aspect that has not been addressed so far is connected with their chirality. Herein, we explore by theoretical and experimental methods this structural aspect that has been so far neglected. First, a computational analysis is conducted and results are used as a guideline for experimental investigation. Next, an array of different experiments (HPLC on chiral columns, chiroptical spectroscopy, X-ray diffraction) for structure elucidation are scrutinized in concert. Finally, this work demonstrates the chirality and the stereodynamic behavior of dibenzocycloctynes and of their triazole adducts with simple azides and uncover their conformational behavior.
ARTICLE | doi:10.20944/preprints202210.0372.v1
Subject: Chemistry And Materials Science, Applied Chemistry Keywords: Keywords carbochlorination; spent lithium-ion batteries; circular economy; recycle; LiCl.
Online: 25 October 2022 (02:05:51 CEST)
The abundant use of lithium-ion batteries (LIBs) in a wide variety of electric devices and vehicles will generate a large number of depleted batteries, which contain several valuable metals such as Li, Co, Mn, and Ni present in the structure of the cathode material (LiMO2). The present work investigates chemical, technological, and environmental aspects in the treatment of such wastes, development of a methodology for the extraction of lithium, cobalt, nickel, manganese, and graphite by a carbochlorination pyrometallurgical process. Mixtures of cathode and anode materials (called black mass, mixed oxides of Li, Co, Ni, Mn, and graphite) from different LIBs, carbon black (as reducing agent), and CaCl2 (as chlorinating agent) were used. Non-isothermal thermogravimetric tests up to 850°C and isothermal tests at 700°C of the mixtures in an inert atmosphere were carried out. It was experimentally observed that the LiMO2-C-CaCl2 reaction takes place at 700°C. LiCl, Ni, and Co were obtained as final products, and to a lesser extent, CoO, NiO, and MnO2. CaCO3 was also obtained as a by-product. The obtained results show that carbochlorination is an efficient and effective alternative route for the extraction and recovery of metals from different LIBs, focused on the sustainability and circular economy
ARTICLE | doi:10.20944/preprints202205.0391.v1
Subject: Business, Economics And Management, Business And Management Keywords: circularity of materials; circular activity; recycling; regression model; key elements
Online: 30 May 2022 (09:59:03 CEST)
The authors have revised the circularity of materials, which is important to stimulate circular activity processes. The theoretical part starts with describing the characteristics of the circular activity and the comparison of circular and linear systems in terms of recycling. Later on, the authors examined key elements important for the circularity and the results of an examination of various sectors. The authors formed a correlation matrix and used a dynamic regression model to identify the circular material use rate. The authors suggested a three-level methodology, using it provided a dynamic regression model which could be applied for forecasting the size of circular material use rate in European Union countries. The results show that private investments into recycling and the recycling of electronic waste and the recycling of other municipal waste categories are important in seeking to increase the usage rate of circular materials.
ARTICLE | doi:10.20944/preprints202203.0195.v1
Subject: Engineering, Architecture, Building And Construction Keywords: circular meshes; free-form surfaces; 3D concrete printing; shell structures
Online: 15 March 2022 (06:51:19 CET)
Shell-like, double curved and thus above-average performance structures, are usually produced monolithically on site. For industrial advancement, however, they must be divided into transportable modules which can be assembled on the construction site (design for assembly). Models are lattice shells made of steel and glass, in which predominantly flat sub-surfaces (modules) are used. Therefore, the main question is: Which modularizations are suitable for flow production with mineral building materials? In this paper designed free-form surface is going to be discretized as PQ circular mesh system, suitable modules for 3D concrete printing. Moreover, the multi-criteria optimization is done with Response Surface Methodology (RSM) in order to get optimal final shape. The goal is to start from the arbitrary shape, that can be generated from two curves, with possible two-way division into modules and compare it with the resulted discretized PQ circular mesh system, realized with new algorithm. The comparison can be defined through two main criteria: geometrical and structural.
ARTICLE | doi:10.20944/preprints202203.0092.v1
Subject: Engineering, Architecture, Building And Construction Keywords: Circular Economy; Built Environment; Reuse; Upcycling; Industrial Waste; Urban Waste
Online: 7 March 2022 (09:14:42 CET)
The growing concern about climate change and the recognition of the planet’s limits led society to look for alternatives that promote the balance between the natural and the built environment. The circular economy emerges as an alternative to the linear economic model, inspired by natural metabolisms, by circulating resources in continuous loops, where their intrinsic value is maintained and improved. This research proposes a closed-loop strategy in the built environment by studying innovative constructive solutions that aim to find use, value, and inspiration in what is considered waste. A literature review is conducted on the circular design strategies, re-use and recycle typologies, and waste transformation processes. Then, the development of a methodology for qualitative evaluation and selection of re-used and upcycled construction materials from post-consumer waste and by-products is presented and then applied to thirty-five cases of constructive solutions from plastic, wood, paper, steel, aluminium, and agricultural waste. The research reports that the developed framework is adequate. The analysed alternative materials have good environmental performance and can be used as building materials despite their functional limitations, reflecting the enormous potential of waste as a resource for the construction industry.
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: circular RNAs (circRNAs); biogenesis; trans-acting proteins; cis-regulatory elements
Online: 16 July 2021 (14:48:13 CEST)
Circular RNAs (circRNAs), which are a class of non-coding RNA with covalently closed loops, play important roles in epigenetics regulation of gene expression at both the transcriptional and post-transcriptional level. Accumulating evidence demonstrated that numerous circRNAs were abnormally expressed in tumors and their dysregulation was involved in the tumorigenesis and metastasis of cancer. Although the functional mechanisms of many circRNAs have been revealed, why circRNAs are dysregulated in cancer remains elusive. CircRNAs are generated by a “backsplicing” process, which is regulated by different cis-regulatory elements and trans-acting proteins. Therefore, how these cis- and trans-elements change during tumorigenesis and how they regulate the biogenesis of circRNAs in cancer are two questions that interest us. In this review, we summarized the pathways for the biogenesis of circRNAs; and then illustrated why circRNAs dysregulated in cancer by discussing the changes of cis-regulatory elements and trans-acting proteins that related to circRNA splicing and maturation in cancer.
ARTICLE | doi:10.20944/preprints202107.0371.v1
Subject: Physical Sciences, Acoustics Keywords: circular torus; nonlinear deformation; shear deformation; Mindlin; Gauss curvature; Maple
Online: 16 July 2021 (12:47:16 CEST)
The nonlinear deformation and stress analysis of a circular torus is a difficult undertaking due to its complicated topology and the variation of the Gauss curvature. A nonlinear deformation (only one term in strain is omitted) of Mindlin torus was formulated in terms of the generalized displacement, and a general Maple code was written for numerical simulations. Numerical investigations show that the results obtained by nonlinear Mindlin, linear Mindlin, nonlinear Kirchhoff-Love, and linear Kirchhoff-Love models are close to each other. The study further reveals that the linear Kirchhoff-Love modeling of the circular torus gives good accuracy and provides assurance that the nonlinear deformation and stress analysis (not dynamics) of a Mindlin torus can be replaced by a simpler formulation, such as a linear Kirchhoff-Love theory of the torus, which has not been reported in the literature.
ARTICLE | doi:10.20944/preprints202010.0044.v1
Subject: Environmental And Earth Sciences, Waste Management And Disposal Keywords: Scrap; waste; materials; trade; resource flows; embedded emissions; circular economy
Online: 2 October 2020 (13:56:05 CEST)
Growing evidence about the negative socio-environmental consequences of plastic pollution led to various initiatives for better plastic scrap governance and its trade. At the same time, an examination of recent data shows that plastic scrap represents only a fraction of recyclable materials which are traded internationally and are also subject to similar problems of cross-border environmental governance. A limited analysis comparing plastics, textiles, paper and ferrous metals suggests that ongoing momentum for improvement of plastic scrap governance and circularity should also be framed to consider other types of secondary materiais.
ARTICLE | doi:10.20944/preprints202006.0273.v1
Subject: Physical Sciences, Optics And Photonics Keywords: femtosecond laser; plasma channel; filament elongation; circular aperture quartz plate
Online: 21 June 2020 (14:29:42 CEST)
We propose a new approach of extending the laser filament plasma channel. By adding a circular aperture quartz plate before the focusing lens, the extension of the plasma channel is doubled. The effects of different diameters, thicknesses of the circular aperture quartz plate and different pulse energies on the length of the plasma channel were investigated. The experimental results show that the thickness of the quartz plate and the depth of the hole have little effects on the plasma channel of the filament, and the diameter of the hole in the center of the quartz plate has a significant effect on the length of the optical filament. The moving-focus model is used to explain the extension of the optical filament.
ARTICLE | doi:10.20944/preprints201809.0037.v1
Subject: Engineering, Architecture, Building And Construction Keywords: residential house; deconstruction; resource harvesting; whole house reuse; circular economy
Online: 3 September 2018 (13:49:34 CEST)
This study analyses the case study of a deconstruction project called the ‘Whole House Reuse’ (WHR) which aimed, firstly, to harvest materials from a residential house, secondly, to produce new products using the recovered materials, and thirdly, to organize exhibition for the local public to promote awareness on resource conservation and sustainable deconstruction practices. The study applies characterization of recovered materials through deconstruction. In addition to the material recovery, the study assesses the embodied energy saving and greenhouse gas emission abatement of the deconstruction project. Around twelve tonnes of various construction materials were harvested through a systematic deconstruction approach, most which would otherwise be disposed to landfill in the traditional demolition approach. The study estimates that the recovered materials could potentially save around 502,158MJ of embodied energy and prevent carbon emission of around 27,029kg (CO2e). Deconstruction could eventually contribute to New Zealand’s national emission reduction targets. In addition, the project successfully engages local communities and designers to produce 400 new products using the recovered materials and exhibited to the local people. The study concludes that there is a huge prospect in regard to resource recovery, emission reduction, employment and small business opportunities using deconstruction of the old house. The socio-cultural importance of the WHR project is definitely immense; however, the greater benefits of such projects are often ignored and remain unreported to wider audiences as most of the external and environmental costs have not been considered in the traditional linear economy. It is acknowledged that under a favourable market condition and with appropriate support from local communities and authorities, deconstruction could contribute significantly to resource conservation and environmental protection despite its requirement of labour intensive efforts.
ARTICLE | doi:10.20944/preprints201704.0191.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: uniform circular array; source localization; least square algorithm; lossy medium
Online: 28 April 2017 (11:09:06 CEST)
In this paper, the methods and their analysis for estimating the location of three dimension (3-D) single source buried in lossy medium are presented with uniform circular array (UCA). The mathematical model of the signal in the lossy medium is proposed. Using location information in the covariance matrix obtained by sensors’ output, the equations of the source location (azimuth angle, elevation angle and range) are obtained. The phase and amplitude of the covariance matrix function are used to process these equations respectively. Then, the phase and amplitude of the covariance matrix function are used to process the source localization in the conductive medium together. By analyzing the characteristics of the proposed methods and MUSIC method, the computational complexity and the valid range of these methods are given. From the results, whether the loss is known, we can choose the appropriate method to process the issues (localization in lossless medium or lossy medium).
ARTICLE | doi:10.20944/preprints202311.1241.v1
Subject: Business, Economics And Management, Business And Management Keywords: Energy Sector; Circular Economy; Sustainable Development Goals; SDG; Text Mining; VOSviewer
Online: 20 November 2023 (13:56:34 CET)
This text mining study delves into the multifaceted contributions of the energy sector to the Sus-tainable Development Goals (SDGs). By analyzing a wide range of academic literature, we un-cover key themes, trends, and challenges shaping the intersection of energy and sustainability. The findings reveal that the energy sector plays a pivotal role in achieving SDGs such as affordable and clean energy (SDG 7) and climate action (SDG 13). Critical issues encompass governance, policy frameworks, and technological innovations. This research underscores the need for inter-disciplinary collaboration and holistic approaches in addressing complex energy-related sus-tainability challenges. The insights derived here provide guidance to policymakers, researchers, and stakeholders seeking to harness the energy sector's potential for a more sustainable and eq-uitable future.
ARTICLE | doi:10.20944/preprints202306.0367.v1
Subject: Engineering, Telecommunications Keywords: Aerial base station; Multiple drones; Circular polarization; Two-ray model; Antennas
Online: 6 June 2023 (03:46:35 CEST)
In recent years, drones have been used in a wide range of fields such as agriculture, transportation of goods, and security. Drones equipped with communication facilities are expected to play an active role as base stations in areas where ground base stations are unavailable, such as disaster areas. In addition, asynchronous operation is being considered for local 5G in order to support all kinds of use cases. In asynchronous operation, cross-link interference between base stations is an issue. This paper attempts to reduce the interference caused by the drone network by introducing circularly polarized antennas. Numerical analyses are conducted to validate the effectiveness of the proposed system, where SIRs (Signal-to-Interference Ratio) are shown to be improved significantly as the numerical evaluation results.
ARTICLE | doi:10.20944/preprints202210.0188.v1
Subject: Medicine And Pharmacology, Ophthalmology Keywords: Glaucoma; Optical Coherence Tomography; Circular Statistics; Directional Statistics; RNFL; Clus-tering
Online: 13 October 2022 (07:36:37 CEST)
Using the OCT platform, we can generate high-resolution data on retinal nerve fiber layer (RNFL) thickness in a given eye at a large number of angular-points defined on a circular coordinate system. However, insightful characteristics of OCT RNFL data such as its circularity and granularity generally remain unutilized in its common downstream statistical analyses. We present a new circular statistical framework that defines an Angular Decay function and thereby provides a directional representation of an eye in terms of its focused RNFL loss. By applying to a clinical cohort of Asian Indian eyes, the generated circular data was modeled with a finite mixture of von Mises distributions, which led to unsupervised identification in different age-groups of 2 recurrent clusters of glaucomatous eyes with distinct directional signatures of RNFL decay. New indices of global and local RNFL loss were computed for comparing the structural differences between these glaucoma clusters across the age-groups.
ARTICLE | doi:10.20944/preprints202011.0226.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: activated carbon; hydrothermal carbonization (HTC); exergy analysis; thermoeconomic analysis; circular economy.
Online: 6 November 2020 (08:07:04 CET)
An activated carbon manufacturing process using winemaking waste is analyzed and designed at industrial scale. Starting from experimental research, the chemical transformations and thermodynamics during pruning wood conversion are studied as a basis for plant design. In this way, mass and energy balances of hydrothermal carbonization and physical activation are fulfilled and a thermoeconomic methodology is applied to develop an energy-integrated plant. To achieve this target, a network of heat exchangers is allocated to minimize heat consumption and supply hot domestic water, while a cogeneration cycle is designed to provide electricity and satisfy the remaining heat demand. Furthermore, a sensitivity analysis is carried out to determine the influence of the production scale and other operation parameters, such as annual workload, service life, and capital and feedstock costs, on the economic viability of the plant. The energy balance of the plant indicates that the energy integration design manages to provide 48.9% of the overall process energy demand by crossing hot and cold streams and recovering heat from residual flue gas. On the other hand, the exergy cost analysis identifies the combustion of pruning wood used to provide heat demands as the main source of exergy destruction, confirming the suitability of integration to improve the thermodynamic performance. Including activated carbon production, electricity, and hot domestic water, the exergy efficiency of the plant stands at 11.5%.
ARTICLE | doi:10.20944/preprints202010.0589.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: Natural Hydrogen System; circular depressions; Archean iron-rich Craton; Western Australia
Online: 28 October 2020 (11:57:31 CET)
There is a marked momentum towards the use of clean hydrogen energy as an alternative for fossil fuels. Renewable energies such as solar and wind are being used to generate hydrogen from the water hydrolysis process. Indeed, this approach stores renewable energies in the form of combustible hydrogen for other energy uses. The other alternative that could be economically more cost-effective at the current technology stage is to explore the natural “Hydrogen System” where the natural hydrogen is generated and accumulated within the earth system, the same that stands for a “Petroleum System”. The Discovery of a large accumulation of relatively pure natural hydrogen (H2) in Mali has triggered the opportunity of searching for natural hydrogen accumulations in other countries. The generation of hydrogen from a circular depression in Mali and some other countries is linked to the presence of geologically very old iron-rich basement rocks. Solid-liquid redox reactions between iron-rich minerals and groundwater that split water are a possible source of H2 in deep basement rocks. It is believed that the hydrogen degassing may be detected by surface topographic circular to sub-circular shallow depressions. Chemical processes such as dissolution by hydrogen are considered to play the main role in the formation of the circular depressions through preferential vertical hydrogen migration channel. Archean iron-rich Yilgarn Craton that covers a vast area of Western Australia (WA) contains abundant iron-rich mafic-ultramafic rocks. The craton reveals many surficial circular depressions visible through satellite images. The area has abundant fault systems and is blanketed with Eocene sedimentary rocks containing high-quality reservoir rocks. All these characteristics seem to provide most of the required elements, such as hydrogen source, migration pathway, and reservoir rock for a “Hydrogen System” in this area.
ARTICLE | doi:10.20944/preprints202005.0214.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: Wilkinson power divider; RFID; dual port feeder; port distance; circular polarization
Online: 12 May 2020 (12:48:32 CEST)
In this paper a microstrip Wilkinson power divider with a 90° phase delay at one output port is proposed to obtain circular polarization to feed a dual port RFID antenna. The 90° phase delay was obtained by embedding an extra quarter wavelength at one port of the Wilkinson power divider. The feeding circuit is then mounted on the ground plane of the microstrip antenna feeding the radiating patch directly through the ground plane and dielectric layer thus reducing any fringing effect and resulting a mechanically compact unit. The proposed feeding method offers better expectation of antenna performance with minimal attenuation and coupling losses. The design process generalizes geometric pa- rameters of the Wilkinson power divider for variable port distances. The paper considers both UK and US RFID center frequencies, 870 MHz and 915 MHz respectively. Numeri- cally computed values for geometric design parameters for both frequencies are tabled as future design tools for port distances varying from 18 mm up to 34 mm at 870 MHz and 17 mm up to 32 mm at 915 MHz. Simulation results indicate a return loss (S11) of -20 dB and -26 dB at 870 MHz and 915 MHz operational frequencies respectively at 270° angled quarter wavelength.
ARTICLE | doi:10.20944/preprints201809.0295.v2
Subject: Engineering, Mechanical Engineering Keywords: FGM porous circular plate; free vibration; exact solution; multiparametric frequency equations
Online: 18 October 2018 (06:23:35 CEST)
Free vibration analysis of the porous functionally graded circular plates has been presented on the basis of classical plate theory. The three defined coupled equations of motion of the porous functionally graded circular/annular plate were decoupled to one differential equation of free transverse vibrations of plate. The one universal general solution was obtained as linear combination of the multiparametric special functions for the functionally graded circular and annular plates with even and uneven porosity distributions. The multiparametric frequency equations of functionally graded porous circular plate with diverse boundary conditions were obtained in the exact closed-form. The influences of the even and uneven distributions of porosity, power-law index, diverse boundary conditions and the negligibled effect of the coupling in-plane and transverse displacements on the dimensionless frequencies of the circular plate were comprehensively studied for the first time. The formulated boundary value problem, the exact method of solution and the numerical results for the perfect and imperfect functionally graded circular plates have not yet been reported.
ARTICLE | doi:10.20944/preprints201801.0272.v2
Subject: Physical Sciences, Particle And Field Physics Keywords: circular array; current measurement; un-center; un-perpendicular; Tunnel Magnetoresistance sensors
Online: 15 February 2018 (16:32:12 CET)
This paper analyzes the measurement error, caused by the position of the current-carrying conductor, of circular array of magnetic sensors for current measurement. The circular array of magnetic sensors is an effective approach for AC or DC non-contact measurement, as its low cost, large linear range, wide bandwidth, light weight and low noise. Especially it has claimed that such structure has the excellent reduction ability for the errors caused by the position of the current-carrying conductor, crosstalk current interference, shape of the conduction cross section and the earth magnetic field. However, the positions of the current-carrying conductor, including un-center and un-perpendicularity, has not analyzed in detail until now. In this paper, the theoretical analysis has been proposed based on vector inner and exterior product. In the presented mathematical model of relative error, the un-center offset distance, the un-perpendicular angle, the radius of the circle and the number of the magnetic sensor are expressed in one equation. The comparison of the relative error caused by the position of the current-carrying conductor between four and eight sensors is conducted. The Tunnel Magnetoresistance (TMR) sensors are used in the experimental prototype to verify the mathematical model. The analysis results can be the reference to design the detail of circular array of magnetic sensors for current measurement in practical situation.
REVIEW | doi:10.20944/preprints202311.0935.v1
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: manufacturing waste; sustainable energy generation; circular economy; future trends in waste utilization
Online: 14 November 2023 (13:35:42 CET)
The paper presents a thorough examination of the burgeoning field of utilizing manufacturing waste for sustainable energy generation, aligning with the global imperative for resource efficiency and clean energy solutions. With the manufacturing sector being a significant contributor to waste generation, this study explores innovative approaches to transform waste materials into valuable resources, thereby mitigating environmental impacts and contributing to a circular economy. This work critically reviews current trends, emphasizing technological advancements, policy interventions, and market dynamics shaping the manufacturing waste utilization landscape. Noteworthy developments, such as advanced sorting technologies and the integration of digital solutions, are discussed in detail, showcasing their role in enhancing the efficiency of waste management processes. The study outlines future trends in the field, anticipating a shift towards closed-loop systems guided by circular economy principles. This comprehensive review aims to contribute to the discourse on sustainable waste management and energy generation by providing a holistic perspective on the field's current state and offering insights into the future trajectories that will propel manufacturing waste toward a more sustainable and circular future. The synthesis of technological innovation, collaborative efforts, and evolving regulatory frameworks presents a compelling case for the continued exploration of manufacturing waste as a valuable resource in the pursuit of a more sustainable and energy-efficient world.
ARTICLE | doi:10.20944/preprints202305.1031.v1
Subject: Computer Science And Mathematics, Artificial Intelligence And Machine Learning Keywords: Additive manufacturing; Artificial intelligence; Design customisation; Wheelchair; Footrest; Kyklos 4.6; Circular economy
Online: 15 May 2023 (10:48:22 CEST)
In the current paper, we present our work towards developing a solution combining computer vision and AI to support footrest design customization in the wheelchair industry. Wheelchairs and postural systems are complex and often user centric in the design process. Those products require a wide range of adjustments to adapt to the various anthropometries and disabilities of patients. Most commercial products, dedicated to severe disability, also include a series of additional elements, designed to keep the patient in a comfortable but “fixed” position. Such systems do not allow to “fix and maintain” the position of patient foot, especially for patients who have no control over their lower limbs. For that reason, it becomes essential to supply wheelchairs with specific elements to hold patient's shoe in place. Commercial foot supports are typically developed on standard sizes and do not always cover the entire population. In addition, those designs are based on standard shoes, thus they do not lend themselves well to adapting to special shoes or orthopedic shoes. Feet final position therefore becomes a key element in correct postural management. In this paper, we investigate the use of computer vision and AI to correctly define customization parameters of the footrest. The proposed design has been developed based on the specifications received from the Pro Medicare S.r.l orthopedic technicians. We present suitable algorithms, design principles and well defined components towards the implementation of our proof of concept. We also present the testing activities we have undertaken and the obtained performance results.
ARTICLE | doi:10.20944/preprints202304.0886.v1
Subject: Social Sciences, Education Keywords: POGIL-based instruction; lecture-based instruction; unit of circular motion; science performance
Online: 25 April 2023 (04:23:47 CEST)
The aim of this study was to investigate the impact of Process Oriented Guided Inquiry Learning (POGIL)-based instruction versus lecture-based instruction on Grade 12 students’ performance in circular motion unit. A quasi-experimental, pretest-posttest design, the impact of POGIL-based instruction versus lecture-based instruction on students’ performance as measured by three types of cognitive outcomes: Knowing, Applying and Reasoning (KAR). The total number of participants was approximately 110 students (N=110); 54 were assigned to treatment groups (25 girls and 29 boys) and 56 were assigned to control groups (27 girls and 29 boys). The treatment group was taught a unit of circular motion in physics using POGIL-based instruction while the control group was taught the unit using lecture-based instruction. The findings of the study showed statistically significant differences between students of the control group and the treatment group in favor of the later regarding their circular motion performance, suggesting the superiority of the POGIL in enhancing student understanding of the circular motion.