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- Ammenberg, Jonas, et al.
(författare)
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Improving the CO2 performance of cement, part III : The relevance of industrial symbiosis and how to measure its impact
- 2015
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Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 98, s. 145-155
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Tidskriftsartikel (refereegranskat)abstract
- Cement production contributes to extensive CO2 emissions. However, the climate impact can vary significantly between different production systems and different types of cement products. The market is dominated by ordinary Portland cement, which is based on primary raw materials and commonly associated with combustion of vast amounts of fossil fuels. Therefore, the production of Portland cement can be described as a rather linear process. But there are alternative options, for example, involving large amounts of industrial byproducts and renewable energy which are more cyclic and thus can be characterized as relatively “synergistic”.The main purpose of this article is to study how relevant the leading ideas of industrial symbiosis are for the cement industry based on a quantitative comparison of the CO2 emissions from different cement production systems and products, both existing and hypothetical. This has been done by studying a group of three cement plants in Germany, denoted as ClusterWest, and the production of cement clinker and three selected cement products. Based on this analysis and literature, it is discussed to what extent industrial symbiosis options can lead to reduced CO2 emissions, for Cluster West and the cement industry in general.Utilizing a simplified LCA model (“cradle to gate”), it was shown that the CO2 emissions from Cluster West declined by 45% over the period 1997e2009, per tonne of average cement. This was mainly due to a large share of blended cement, i.e., incorporation of byproducts from local industries as supplementary cementitious materials. For producers of Portland cement to radically reduce the climate impact it is necessary to engage with new actors and find fruitful cooperation regarding byproducts, renewable energy and waste heat. Such a development is very much in line with the key ideas of industrial ecology and industrial symbiosis, meaning that it appears highly relevant for the cement industry to move further in this direction. From a climate perspective, it is essential that actors influencing the cement market acknowledge the big difference between different types of cement, where an enlarged share of blended cement products (substituting clinker with byproducts such as slag and fly ash) offers a great scope for future reduction of CO2 emissions.
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- Ammenberg, Jonas, 1973-, et al.
(författare)
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Industrial symbiosis for improving the CO2-performance of cement
- 2012
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Konferensbidrag (refereegranskat)abstract
- Justification of the paper Cement production is one of the largest contributors to global CO2-emissions. However, the context and characteristics of the production and the cement products vary a lot. A significant part of the production must be characterized as rather linear, for example, to a large extent based on fossil fuels and involving material flows that are not closed. But there are also much more synergistic examples, involving industrial by-products, renewable energy, etc. Clearly, there are opportunities for improvement within the cement industry and it is interesting to analyze to what extent increased industrial symbiosis can lead to improved climate performance. This has been done by studying the production of cement clinker and three selected cement products produced within the Cluster West in Germany, consisting of three cement plants that are owned by the multinational company CEMEX. The methodology is mostly based on Life Cycle Assessment (LCA), from cradle-to-gate.PurposeThe overall purpose is to contribute to a better understanding of the climate performance of different ways of producing cement, and different cement products. The climate impact is assessed for “traditional”, rather linear, ways of making cement, but also two more synergistic alternatives, where the by-product granulated blast furnace slag (GBFS) is utilized to a large extent, substituting cement clinker. It is also shown how the climate performance of the West Cluster has changed from 1997 until 2009 (the main year of study), and investigated how further industrial symbiosis measures could improve the performance.Theoretical frameworkTo a large extent this project has been based on mapping and analysis of relevant flows of material and energy, where LCA methodology has played an important part. Theoretical and methodological aspects related to the fields of Industrial Ecology and Industrial Symbiosis have played an important role. The findings are discussed in relation to some of the key ideas within these fields. The paper generates insight into the methodological challenge of quantifying environmental performance of different production approaches and basically what CO2 improvement potential cement industry has by taking industrial symbiosis measures.ResultsThe results showed that the cement clinker produced at Cluster West is competitive from a climate perspective, causing CO2-eq missions that are a couple of percent lower than the world average. During the twelve year period from 1997 to 2009 these emissions became about 12 percent lower, which was mainly achieved by production efficiency measures but also via changing fuels. However, the most interesting results concern the blended cement products. It was manifested that it is very advantageous from a climate perspective to substitute clinker with granulated blast furnace slag. For example, the CO2-eq emissions were estimated to be 65 percent lower for the best product compared to “ordinary cement”.ConclusionsInformation and measures at the plant level are not sufficient to compare products or to significantly reduce the climate impact related to cement. To achieve important reductions of the emissions, measures and knowledge at a higher industrial symbiosis level are needed.
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- Ammenberg, Jonas, 1973-, et al.
(författare)
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Industrial symbiosis for improving the CO2-performance of cement production : Final report of the CEMEX-Linköping University industrial ecology project, 2011
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report contains information about a research project lead by researchers from Environmental Technology and Management at Linköping University in Sweden. It has been conducted in cooperation with staff from the global cement company CEMEX. The study has been focused on three cement plants in the western parts of Germany, referred to as CEMEX Cluster West. They form a kind of work alliance, together producing several intermediate products and final products. One of the plants is a cement plant with a kiln, while the other two can be described as grinding and mixing stations. The overall aim has been to contribute to a better understanding of the climate performance of different ways of producing cement, and different cement products. An important objective was to systematically assess different cement sites, and production approaches, from a climate perspective, thereby making it easier for the company to analyze different options for improvements. Theoretical and methodological aspects related to the fields of Industrial Ecology (IE) and Industrial Symbiosis (IS) have played an important role. A common way of making cement is to burn limestone in a cement kiln. This leads to the formation of cement clinker, which is then grinded and composes the main component of Ordinary Portland Cement. One very important phase of the production of clinker is the process of calcination, which takes place in the kiln. In this chemical reaction calcium carbonate decomposes at high temperature and calcium oxide and carbon dioxide are produced. The calcination is of high importance since it implies that carbon bound in minerals is transformed to CO2. A large portion of the CO2 emissions related to clinker production is coming from the calcination process. Both clinker and Ordinary Portland Cement (CEM I 42.5) were studied. However, there are other ways of making cement, where the clinker can be substituted by other materials. Within Cluster West, granulated blast furnace slag from the iron and steel industry is used to a large extent as such a clinker substitute. This slag needs to be grinded, but an important difference compared to clinker is that it has already been treated thermally (during iron production) and therefore does not have to be burned in a kiln. With the purpose to include products with clearly different share of clinker substitutes, the project also comprised CEM III/A 42.5 (blended cement, about 50% clinker) and CEM III/B 42.5 N-. (blended cement, about 27% clinker). To sum up, this means that the study involved “traditional”, rather linear, ways of making cement, but also two more synergistic alternatives, where a byproduct is utilized to a large extent instead of clinker. The methodology is mostly based on Life Lycle Assessment (LCA), from cradle-to-gate, using the SimaPro software. This means that the cement products have been studied from the extraction of raw materials until they were ready for delivery at the “gate” of Cluster West. The functional unit was 1 tonne of product. A lot of data was collected regarding flows of material and energy for the year of 2009. In addition, some information concerning 1997 was also acquired. Most of the used data has been provided by CEMEX, but to be able to cover upstream parts of the life cycle data from the Ecoinvent database has also been utilized. The extensive data concerning 2009 formed the base for the project and made it possible to study the selected products thoroughly for this year. However, the intention was also to assess other versions of the product system – Cluster West in 1997 and also a possible, improved future case. For this purpose, a conceptual LCA method was developed that made it possible to consider different products as well as different conditions for the product system. Having conducted the baseline LCA, important results could be generated based on knowledge about six key performance indicators (KPIs) regarding overall information about materials, the fuel mix and the electricity mix. The conceptual LCA method could be used for other products and versions of Cluster West, without collecting large amounts of additional specific Life Cycle Inventory (LCI) data. The developed conceptual LCA method really simplified the rather complex Cluster West production system. Instead of having to consider hundreds of parameters, the information about the six KPIs was sufficient to estimate the emissions from different products produced in different versions of the production system (Cluster West). The results showed that the clinker produced at Cluster West is competitive from a climate perspective, causing CO2-eq missions that are a couple of percent lower than the world average. During the twelve year period from 1997 to 2009 these emissions became about 12 percent lower, which was mainly achieved by production efficiency measures but also via changing fuels. However, the most interesting results concern the blended cement products. It was manifested that it is very advantageous from a climate perspective to substitute clinker with granulated blast furnace slag, mainly since it reduces the emissions accounted related to calcination. For example, the CO2-eq emissions related to CEM III/B product were estimated to be 65 percent lower than those for CEM I. A framework for identifying and evaluating options for improvement has been developed and applied. Based on that framework the present production system was analyzed and illustrated, and different measures for reducing the climate impact were shown and evaluated. Two possible scenarios were defined and the conceptual LCA model used to estimate their climate performance. The authors’ recommendation is for CEMEX to continue to increase the share of CEM III (the share of good clinker substitutes), and to make efforts to shift the focus on the market from clinker and cement plants to different types of cement (or concrete) or even better to focus on the lifecycle of the final products such as buildings and constructions. Information and measures at the plant level are not sufficient to compare products or to significantly reduce the climate impact related to cement. To achieve important reductions of the emissions, measures and knowledge at a higher industrial symbiosis level are needed.
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- Andersson, Kennet, 1979-, et al.
(författare)
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Assessment of cerebrospinal fluid outflow conductance using an adaptive observer-experimental and clinical evaluation
- 2007
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Ingår i: Physiological Measurement. - : IOP Publishing. - 0967-3334 .- 1361-6579. ; 28:11, s. 1355-1368
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Tidskriftsartikel (refereegranskat)abstract
- Idiopathic normal pressure hydrocephalus (INPH) patients have a disturbance in the dynamics of the cerebrospinal fluid (CSF) system. The outflow conductance, C, of the CSF system has been suggested to be prognostic for positive outcome after treatment with a CSF shunt. All current methods for estimation of C have drawbacks; these include lack of information on the accuracy and relatively long investigation times. Thus, there is a need for improved methods. To accomplish this, the theoretical framework for a new adaptive observer (OBS) was developed which provides real-time estimation of C. The aim of this study was to evaluate the OBS method and to compare it with the constant pressure infusion (CPI) method. The OBS method was applied to data from infusion investigations performed with the CPI method. These consisted of repeated measurements on an experimental set-up and 30 patients with suspected INPH. There was no significant difference in C between the CPI and the OBS method for the experimental set-up. For the patients there was a significant difference, −0.84 ± 1.25 µl (s kPa)−1, mean ± SD (paired sample t-test, p < 0.05). However, such a difference is within clinically acceptable limits. This encourages further development of this new real-time approach for estimation of the outflow conductance.
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- Devinney, Hannah, 1995-, et al.
(författare)
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Developing a multilingual corpus of wikipedia biographies
- 2023
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Ingår i: International conference. Recent advances in natural language processing 2023, large language models for natural language processing. - Shoumen, Bulgaria : Incoma ltd.. - 9789544520922
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Konferensbidrag (refereegranskat)abstract
- For many languages, Wikipedia is the mostaccessible source of biographical information. Studying how Wikipedia describes the lives ofpeople can provide insights into societal biases, as well as cultural differences more generally. We present a method for extracting datasetsof Wikipedia biographies. The accompanying codebase is adapted to English, Swedish, Russian, Chinese, and Farsi, and is extendable to other languages. We present an exploratory analysis of biographical topics and gendered patterns in four languages using topic modelling and embedding clustering. We find similarities across languages in the types of categories present, with the distribution of biographies concentrated in the language’s core regions. Masculine terms are over-represented and spread out over a wide variety of topics. Feminine terms are less frequent and linked to more constrained topics. Non-binary terms are nearly non-represented.
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- Eklund, Anton, 1994-, et al.
(författare)
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An empirical configuration study of a common document clustering pipeline
- 2023
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Ingår i: Northern European Journal of Language Technology (NEJLT). - : Linköping University Electronic Press. - 2000-1533. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Document clustering is frequently used in applications of natural language processing, e.g. to classify news articles or create topic models. In this paper, we study document clustering with the common clustering pipeline that includes vectorization with BERT or Doc2Vec, dimension reduction with PCA or UMAP, and clustering with K-Means or HDBSCAN. We discuss the inter- actions of the different components in the pipeline, parameter settings, and how to determine an appropriate number of dimensions. The results suggest that BERT embeddings combined with UMAP dimension reduction to no less than 15 dimensions provides a good basis for clustering, regardless of the specific clustering algorithm used. Moreover, while UMAP performed better than PCA in our experiments, tuning the UMAP settings showed little impact on the overall performance. Hence, we recommend configuring UMAP so as to optimize its time efficiency. According to our topic model evaluation, the combination of BERT and UMAP, also used in BERTopic, performs best. A topic model based on this pipeline typically benefits from a large number of clusters.
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