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| 2. |
- Burman, Magnus, 1966-, et al.
(författare)
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Comparative Life Cycle Assessment (LCA) of theHull of a High Speed Craft
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Ingår i: Composite structures. - 0263-8223 .- 1879-1085.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A comparative Life Cycle Assessment (LCA) has been performed on the hull of a 24 meter long high speed patrol craft. The aim of the study is to compare different structural materials concepts to determine differences and sensitivities in environmental impact, especially in relation to the total impact including fuel burn. The material concepts studied are aluminium and various composite combinations consisting of glass fibre and carbon fibre with vinyl ester resin both as single skins and as sandwich with a Divinycell foam core. For each material concept a unique and weight optimized structural design was employed fulfilling the DNV high speed craft design code [1]. All identical systems and components for the five hull concepts are omitted in the LCA and hence a comparative study is performed focused on the hull structure. The commercial software SimaPro have been utilized for the LCA calculations and the impact assessment method chosen is the CML Baseline 2000. The structural optimization carried out in [1] show that a weight reduction by to up to 50% (on the hull) could be achieved by switching from aluminium to a carbon fibre sandwich concept. The weight reduction switching from glass fibre single skin to a carbon fibre sandwich concept is roughly 20%. The LCA study performed herein shows that, regardless of hull material concept, the environmental impact is by large dominated by the usage phase due to relatively large fuel consumption. A lower structural weight will reduce the fuel consumption and hence the environmental impact. This is illustrated in fig. 1 for the aluminum hull. All different phases of the life cycle are plotted for all environmental impact categories assessed herein. The green color is related to the operation phase and the red is the manufacturing phase. As observed the operation phase is dominating. In fig. 2 are the results from the LCA presented for all hull concepts and for all environmental impact factors. The Al-hull is the concept with highest structural weight (red bars) and hence was found to have the highest environmental impact. The carbon fibre sandwich hull (green bars) had the lowest weight of the five and consequently the lowest environmental impact. In the normalization analysis performed, in which different impact factors are assessed using a common impact unit, three impact factors stand out as dominating, independent of hull concept; Abiotic depletion, Global warming and Acidification. All these impact factors are herein associated with the usage phase and diesel consumption. If the operation phase is omitted and only the manufacturing phase (including the material extraction/manufacturing) is studied the observation is that the aluminium concept still will have the largest environmental impact for all categories. The most significant environmental impact is now on the marine and the fresh water aquatic ecotoxicity which is associated with the aluminium raw material excavation and manufacturing processes.
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| 3. |
- Bridel, Claire, et al.
(författare)
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Diagnostic Value of Cerebrospinal Fluid Neurofilament Light Protein in Neurology : A Systematic Review and Meta-analysis
- 2019
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Ingår i: JAMA Neurology. - : American Medical Association (AMA). - 2168-6149 .- 2168-6157. ; 76:9, s. 1035-1048
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Forskningsöversikt (refereegranskat)abstract
- Importance Neurofilament light protein (NfL) is elevated in cerebrospinal fluid (CSF) of a number of neurological conditions compared with healthy controls (HC) and is a candidate biomarker for neuroaxonal damage. The influence of age and sex is largely unknown, and levels across neurological disorders have not been compared systematically to date.Objectives To assess the associations of age, sex, and diagnosis with NfL in CSF (cNfL) and to evaluate its potential in discriminating clinically similar conditions.Data Sources PubMed was searched for studies published between January 1, 2006, and January 1, 2016, reporting cNfL levels (using the search terms neurofilament light and cerebrospinal fluid) in neurological or psychiatric conditions and/or in HC.Study Selection Studies reporting NfL levels measured in lumbar CSF using a commercially available immunoassay, as well as age and sex.Data Extraction and Synthesis Individual-level data were requested from study authors. Generalized linear mixed-effects models were used to estimate the fixed effects of age, sex, and diagnosis on log-transformed NfL levels, with cohort of origin modeled as a random intercept.Main Outcome and Measure The cNfL levels adjusted for age and sex across diagnoses.Results Data were collected for 10 059 individuals (mean [SD] age, 59.7 [18.8] years; 54.1% female). Thirty-five diagnoses were identified, including inflammatory diseases of the central nervous system (n = 2795), dementias and predementia stages (n = 4284), parkinsonian disorders (n = 984), and HC (n = 1332). The cNfL was elevated compared with HC in a majority of neurological conditions studied. Highest levels were observed in cognitively impaired HIV-positive individuals (iHIV), amyotrophic lateral sclerosis, frontotemporal dementia (FTD), and Huntington disease. In 33.3% of diagnoses, including HC, multiple sclerosis, Alzheimer disease (AD), and Parkinson disease (PD), cNfL was higher in men than women. The cNfL increased with age in HC and a majority of neurological conditions, although the association was strongest in HC. The cNfL overlapped in most clinically similar diagnoses except for FTD and iHIV, which segregated from other dementias, and PD, which segregated from atypical parkinsonian syndromes.Conclusions and Relevance These data support the use of cNfL as a biomarker of neuroaxonal damage and indicate that age-specific and sex-specific (and in some cases disease-specific) reference values may be needed. The cNfL has potential to assist the differentiation of FTD from AD and PD from atypical parkinsonian syndromes.
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| 4. |
- Burman, Magnus, 1966-, et al.
(författare)
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Blister propagation in sandwich panels
- 2019
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Ingår i: Journal of Sandwich Structures and Materials. - : SAGE Publications Ltd. - 1099-6362 .- 1530-7972. ; 21:5, s. 1683-1699
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with the problem of face/core interfacial disbonds in sandwich panels that are pressurised, i.e. the disbond has an initial fluid pressure that causes the disbond to deform. The problem is often referred to as a blister. The panel with a blister is then subjected to an in-plane compressive load. Four different panels are analysed and tested, having different size disbonds and different initial internal pressure. The cases are analysed using a finite element approach where the blister is modelled using fluid elements enabling the pressure inside the blister to vary as the in-plane load is applied. The analysis uses non-linear kinematics, and in each load step, the energy release rate is calculated along the disbond crack front. This model is used for failure load predictions. The four cases are then tested experimentally by filling a pre-manufactured disbond cavity with a prescribed volume of air. This air volume is then entrapped, and the panel is subjected to an in-plane compressive load. The load and blister pressures are measured throughout the test and compared with the finite element analysis. Surface strains and blister deformations are also measured using digital correlation measurements. The predicted failure loads compare well with the experimental results, and so does the blister pressures, the latter at least qualitatively. © The Author(s) 2019.
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| 6. |
- Burman, Magnus, 1966-
(författare)
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Composites in ships
- 2010
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Ingår i: 1st conference on Service vessels for offshore wind park.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Burman, Magnus, 1966-, et al.
(författare)
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Cost and Energy Assessment of a High Speed Ship
- 2008
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Ingår i: International Journal of Small Craft Technology, RINA - Part B. - London : RINA. - 1740-0694. ; 150:1, s. 1-10
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Tidskriftsartikel (refereegranskat)
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| 8. |
- Burman, Magnus, 1966-, et al.
(författare)
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Cost and energy assessment of a high speed ship
- 2006
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Ingår i: Second Conference on High Performance Yacht Design. - 9781622761852
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A comparison in total life cycle costs and energy consumption for one high speed ship design with three different structural materials have been performed. The investigation considers a high speed ferry with a steel hull and an aluminium superstructure, an all aluminium concept and a ship built in sandwich material with carbon fibre faces. The different materials will affect several cost elements during the design, the production and the operation of the ship until and including its disposal. Furthermore, the material selection has an impact on the energy consumption within all stages of the ships life cycle. The assessment is made in a comparative manner. Hence, identical out fitting components, e.g. interior, instrumentation, and ventilation are left out. It is shown that the steel version causes the highest costs and energy consumption. The sandwich construction has the lowest life cycle costs while the aluminium version has the lowest energy consumption. The break-even point between the steel and the composite versions appears after 4 years (only 2 years of operation!), the break-even point between the aluminium and the composite ferry is after 12 years (10 years of operation). A sensitivity analysis with different possible scenarios, e.g. change in interest, petrol cost, maintenance cost, has been performed. All of the investigated scenarios identify the composite version to have the lowest life cycle costs. This paper summarises an original work carried out as a master of science work as given in [1-2].
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