1,720,984 research outputs found
Assessment of GHG emissions from materials during building design - Methods for improved reliability and quality
Full text linkConstruction materials in buildings contribute significantly to climate change. Globally, nations have committed to drastic reductions of greenhouse gases (GHG), among them Norway which has committed to 50-55% reduction by 2030 and 90-95% by 2050. Building material use and the related construction activities are among the areas that must drastically reduce impacts to achieve those goals.
Such mitigation efforts are limited by current assessment methods. Improved methods for esti- mation of these climate change impacts are needed in the early project phases to improve the design and planning. Methods for benchmarking results against reference values are needed both to improve design and for effective regulation. Quantification methods are also immature. Material use in buildings affects the climate over centuries, however, temporal aspects are often ignored in Life Cycle Assessment (LCA). Results too often promise uncontested precision of impacts occurring far into the future. Additionally, the validity of building LCAs is being ques- tioned over inadequate scope and inventory. The goal of this thesis is to contribute with methods addressing those limitations, to enable effective reduction of building materials’ contribution to climate change.
The body of research on the impacts of individual buildings is growing, but the results and data remain inaccessible and incomparable due to insufficient reported information, differences in system boundaries, assumptions, methods, and data used. This inhibits further utilization of results in statistical applications and makes interpretation and validation of results difficult. A database of empirical material use and emission data from building LCA case studies was developed to mitigate these challenges, providing a framework for impact assessment in the planning and design phases. Systematizing and storing relevant information for these case studies in a compatible format enables comparison and harmonization of results across system boundaries and assumptions, improves the transparency and reproducibility of the assessments, and makes utilization of the results in statistical applications possible.
A dynamic LCA method for material use in buildings was developed. It addresses uncertainty and temporal effects arising from the long lifetime of buildings. In particular, novel solutions for accounting for delayed emissions and future emission reductions due to technological im- provements are proposed. Climate change effects of material use in construction, operation, and end-of-life phases are estimated, from production, transport, construction-waste incinera- tion, biogenic carbon-sequestration, and cement carbonation. The importance of choosing a normative time horizon for the estimated climate change impacts is emphasized.
A method was also developed for evaluating and visualizing the climate change impacts of material use by linking the material inventory data with the aggregated results through a set of metrics for a building and its subparts. These subpart metrics can be compared to the rest of the building and to results from other buildings, and statistical benchmarks can be established. This intermediate calculation step simultaneously serves as a breakdown of the results and an aggregation of the building’s inventory data. The subpart metrics lay the foundation for applications throughout the project phases by enabling combined use of case-specific data and statistical data.
Uncertainty is estimated from variation in the dataset, and further, from sampling results while varying assumptions. Parameter influence is assessed with global sensitivity analysis. The time horizon for the impacts, the building lifetime (long time horizons only), and the construction waste parameters are found most sensitive. The method reduces uncertainty of postulated future impacts; an important step in the direction of policy-relevant modeling. It is recommended that building LCA modeling practice adopts the presented methodological concepts to gain trust and policy-relevance.
Case studies are used to demonstrate the methods and to generate statistical results. Rarely have the climate change impacts of material use in buildings been studied by statistical methods, and never this sophisticated. In the early phases of a building project, empirical statistical emission profiles of construction materials can inform mitigation efforts. However, engineers and archi- tects do currently not have sufficient information at disposition. The climate change impacts of building material use in 20 Norwegian case studies of low-emission buildings are made com- parable, harmonized, and then studied statistically to find how the impact varies with building types (typology, timber/ concrete), building subparts (building elements, material categories), and time horizon. Anticipated future technological development, and delaying emissions in the coming decades, will together lead to significant reductions of accumulated impacts and thus reduce the importance of future replacements and end-of-life. Results show that global warming policy targets require that the building industry focuses on interventions with short-term effects, such as low immediate impact of materials in the construction phase, as well as demonstrating the importance of reducing impacts from construction waste throughout the building lifetime
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
Exploring the Integration of Embodied Carbon Assessment in Architectural Design: An Analysis of Current Practices
Full text linkMaterialene som brukes til bygninger står globalt for ca. 28 % av de årlige karbondioksidutslippene i byggesektoren. Sporing av disse innebygde karbonutslippene i et byggeprosjekt gjøres ved å gjennomføre en livssyklusvurdering (LCA). Den norske byggtekniske forskriften TEK 17 vil inkludere en LCA for det ferdige prosjektet som en del av godkjenningsprosessen fra juli 2023 og viser til strengere krav i fremtiden. Med viktigheten av å redusere det innebygde karbonet i bygninger på agendaen, øker naturligvis også behovet for å ta hensyn til innebygd karbon i designprosessen. Arkitekter har stor innflytelse på den arkitektoniske utformingen og dermed på bygningers miljøpåvirkning. Per i dag er imidlertid vurderingen av innebygd karbon ikke godt integrert i designprosessen. Denne studien undersøker hvordan livssyklusvurdering av innebygde karbonutslippene kan integreres i arkitektonisk design.
For å skaffe en god forståelse for temaet og dagens praksis ble det gjennomført et bredt litteraturstudie av prosjekteringsprossessen i Norge samt forskning på om og hvordan LCA av innebygd karbon og relaterte emner blir gjennomført som en del av byggeprossessen. Fem semistrukturerte intervjuer, med fire arkitekter og én ingeniør, ble gjennomført for å få innsikt i arbeidspraksis, prosjektstrukturer, valg under prosjekteringen samt kunnskap og oppfatninger om innebygde utslipp. Fire intervjuer fra skole-prosjektet Voldsløkka, som er relatert til forskningsprosjektet ARV, ble inkludert i intervjuanalysen. Basert på innsikten fra intervjuene ble ulike hensyn knyttet til innebygd karbon og LCA-beregninger utforsket i detalj. Disse tilleggsbetraktningene ga ytterligere innsikt og tok opp kontroverser og usikkerhet som ble identifisert under intervjuene.
Intervjuene ga verdifull innsikt i tre hovedområder: den arkitektoniske designprosessen og involverte parter, integrering av LCA i designprosessen, og hensyn til og påvirkning av innebygd karbon. Den supplerende undersøkelsen gikk nærmere inn på bruken av forenklet dokumentasjon og belyste viktige aspekter å ta hensyn til i LCA-beregninger.
Konklusjonen i denne studien er at integrering av LCA i designprosessen er et felt i utvikling, og i takt med at miljøaspektene får mer oppmerksomhet, utvikler designprosessen seg i retning av en mer tverrfaglig prosess. Integrering av LCA i den tidlige designfasen er avgjørende for en vellykket forbedring av bygningers innebygde karboninnhold, men strømlinjeformede tilnærminger og forståelige retningslinjer må videreutvikles. I tillegg må arkitekter og andre interessenter erkjenne at det å ta hensyn til innebygd karbon er en kompleks og utfordrende oppgave i en allerede kompleks designprosess. Det krever innsats og en bred forståelse av sammenhengene mellom ulike aspekter for å kunne ta informerte beslutninger. Samtidig bør forskere og ingeniører etterstrebe å kommunisere LCA-konsepter på en mer tilgjengelig måte, slik at arkitekter ikke blir overveldet av de store mengdene med informasjon og de ulike beregningsmetodene.The material used in buildings is globally responsible for approximately 28% of the annual carbon dioxide emissions within the building sector. Tracking these embodied carbon emissions within a building project is done by conducting a life cycle assessment (LCA). The Norwegian building code TEK 17 will include an LCA for the finished project as part of the approval process from July 2023 and refers to stricter requirements in the future. With the importance of lowering embodied carbon in buildings on the table, the urgency of including embodied carbon considerations in the design process increases. Architects have a large influence on architectural designs and consequently on the environmental impact of buildings. However, as of now embodied carbon assessment is not well integrated into their design process. This study investigates the integration of embodied carbon assessment in architectural design.
A broad literature review about the design process in Norway as well as research about LCA of embodied carbon and related topics was conducted to investigate the current practice and provide an understanding of the topic. Five semi-structured interviews were conducted, with four architects and one engineer, to gain insight regarding work practices, project structures, choices during the design, and knowledge and perceptions regarding embodied emissions. Four interviews from the Voldsløkka school project, which is related to the research project ARV, were included in the interview analysis. Based on the insights gained in the interviews, various considerations related to embodied carbon and LCA calculations were explored in detail. These additional considerations provided further insights and address controversies and uncertainty identified during the interviews.
The interviews provided valuable insights into three key areas: the architectural design process and involved parties, integration of LCA into the design process, and embodied carbon considerations and influences. The supplementary investigation further delved into the use of simplified documentations and highlighted important aspects to consider in LCA calculations.
This thesis concludes that the integration of LCA into the design process is a developing field and with environmental aspects getting more attention the design process is evolving towards a more interdisciplinary process. Integration of LCA in the early design is crucial for a successful enhancement of the embodied carbon in buildings, but streamlined approaches and understandable guidelines need to be advanced further. Additionally, architects and other stakeholders must acknowledge that addressing embodied carbon is a complex and challenging task within an already compound design process. It requires effort and a broad understanding of the correlations between different aspects to take informed decisions. Simultaneously, researchers and engineers should strive to communicate LCA concepts in a more accessible manner, ensuring that architects are not overwhelmed by the vast amount of information and various calculation approaches
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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