1,720,962 research outputs found
Life Cycle Assessment of Red Mud-Based Geopolymer Production at Industrial Scale
No full textNowadays the production of traditional building materials continues to be highly energy consuming and polluting. Therefore, the development of sustainable materials that allow the reuse of industrial waste could lead to a faster ecological transition of the construction industry. Among lab-scale developed materials, geopolymers are widely recognized as a future and sustainable alternative to traditional Portland cement, allowing to reuse various wastes from different industrial sectors. This paper aims to perform an environmental analysis of geopolymers large-scale production based on the use of red mud, a waste product from the aluminum supply chain. Previous studies on red mud-based geopolymers have focused mainly on optimizing the laboratory formulations, without analyzing their real environmental advantage over traditional building materials. Therefore, this study uses the life cycle assessment approach to verify the environmental benefit of the large-scale production for the circular economy. Starting from the literature analysis, a four-steps scale-up procedure was applied to identify a potential industrial production. Results showed a clear reduction in CO2 emissions compared to the production of conventional Portland cement and highlighted the need to reduce the use of alkaline activators in geopolymers production. © 2023, IFIP International Federation for Information Processing
From lab to industry: Scaling up green geopolymeric mortars manufacturing towards circular economy
No full textConstruction is nowadays considered an extremely energy intensive industry and one of the main sources of environmental pollution in the world. Therefore, the research and the development of novel energy-saving manufacturing processes and sustainable construction materials is more than ever urgent and challenging. This paper aims at identifying the industrial process for the production of novel geopolymers to be used as a greener substitute for cement, especially the Portland one, widely used for structural applications to significantly reduce the environmental impact of the construction industry. Here, the materials sustainability and the manufacturing process are improved by valorising and reusing wastes, deriving from the pulp-paper industry, as raw materials. This industry generates a great quantity of wastes that represent a real concern both for their environmental impact and cost of disposal. The new industrial process was evaluated after scaling up the laboratory procedure to an industrial dimension. Consequently, each small-scale process was deeply analysed (raw materials involved and processes) and transposed into a massive-production. The most relevant processes that show an elevated environmental impact were identified and the energy consumption of the whole process has been assessed resulting, for the analysed geopolymeric product, an embodied energy of 645 MJ/ton, being about one sixth of the OPC. Moreover, a preliminary economic analysis has been conducted in terms of raw materials involved in the proposed industrial process revealing a decreasing cost per ton increasing the waste recycling. All considered, the main conclusions are that the industrial scale up of the proposed geopolymeric product, assessed for the first time in literature along with the related proposed considerations, could be highly competitive to the Portland production involving greener processes with a much lower energy consumption and a greater financial saving by improving the wastes quantity
Development of a Vessel Scheduling Optimization Model to improve Maritime Transport sustainability
Full text linkThe social and economic development of the islands is generally dependent on the interconnection level with the mainland obtained through maritime transport services. When connecting many islands, the route planning is essential and typically a variety of constraints must be considered. Various optimization methods have been established to improve cost-efficiency but today environmental concerns, like the reduction of CO2 emissions, have become mandatory. This paper proposes a vessel scheduling optimization model able to simultaneously consider compulsory and optional tasks and vehicle-dependent profits. The algorithm was applied to seven islands of the Tyrrhenian Sea located in front of Sicily, named “Aeolian Islands”. Considering the regional requirements in terms of minimum number of routes and maximum fare prices for each season, this research compared the optimal vessels option obtained maximizing the profit with the one obtained minimizing the emissions. In particular, we have conducted three different analyses, in the first one we have considered only the mandatory routes while the second one was carried out identifying a series of potentially attractive additional activities based on historical demand data provided by the company that currently manages the service. Finally, the third analysis addresses a scenario where older fuel-powered vessels were replaced with hybrid electric ones
Life cycle analysis of innovative building materials based on circular coffee ground supply chain
Full text linkThe construction sector is widely recognized as one of the most polluting mainly due to its intensive exploitation of natural resources and large energy consumption to produce traditional building materials. In the last years, alternative building materials have been developed with the aim to reduce the environmental burden of this sector. In particular, the use of geopolymer mortars as alternative cementitious materials is gaining increasing acceptance among scientists. Numerous laboratory studies demonstrate their suitability for construction applications, highlighting the potential environmental benefits that can be obtained from their large-scale production. This study aims to perform a preliminary evaluation of the environmental performance of a geopolymer mortar, whose production includes the reuse of a food waste: Spent Coffee Ground (SCG). By using the Life Cycle Assessment (LCA) approach, an environmental comparison with a traditional production of cement mortar was carried out on the basis of the Global Warming Potential (GWP) indicator
Human error contribution to accidents in the manufacturing sector: A structured approach to evaluate the interdependence among performance shaping factors
Full text linkSince the 1970s, Human Reliability Analysis (HRA) methods have received a great interest for the quantification of the Human Error Probability (HEP) in Nuclear Power Plants (NPPs). To this purpose, the second-generation HRA methods consider contextual and cognitive factors - named Performance Shaping Factors (PSFs) - that may influence the workers’ performance during tasks execution. Despite the recent extension of HRA methods to different fields, only few studies refer to the manufacturing sector. In addition, the majority of contributions assume the independence among PSFs, which may result in an over or under estimation of HEP. Therefore, the present paper focuses on the manufacturing sector to propose a Fuzzy DEMATEL (FDEMATEL) based method to support the risk analyst in the quantification of PSF interrelationships and importance, when computing HEP. As a result, the most influential human factors on which taking priority actions to improve the overall human reliability may be identified accurately. Based on a selected list of PSFs, the methodological approach is implemented in an Italian textile company, where experience and training factors are demonstrated to be the most central ones to increase the human reliability when performing the weaving process tasks. The designed approach is well structured and effortless as well as it allows at considering the uncertainty and vagueness of input data and a group decision context
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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