| 1. |
- Andersson, Karin, 1952, et al.
(författare)
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Environmental trade-offs in nitrogen oxide removal from ship engine emissions
- 2011
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Ingår i: Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment. - 2041-3084 .- 1475-0902. ; 225:1, s. 33-42
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Konferensbidrag (refereegranskat)abstract
- The emissions of nitrogen oxides (NOx) from ship engines constitute an increasing part of the total global emissions of NOx while the share from land-based sources is decreasing. In the coming years, new regulations will set limits to emissions in specific areas and various technical countermeasures will be developed and implemented. However, when taking technical measures against emissions on a local scale, there is always a risk of inducing an increase in the total environmental impact related to the technology used, owing to increased energy use and emissions in other places.In the present study, an investigation of the difference in environmental impact from passenger transport vessels with and without catalytic NOx emission purification was performed in a life cycle assessment. The production and transport of chemicals used in the catalyst are included in the study.The study shows that the use of selective catalytic reduction (SCR) gives a considerable decrease in the environmental impact compared with using a diesel engine without a catalyst. The transport of urea solution over a 500 km distance makes a very small contribution to the total environmental impact. The global warming potential is the only impact category for which values are increased when including the urea production and transport. When looking at the contribution from urea to the total impact from the SCR process, the increase is less than 10 per cent for most impact categories.
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| 2. |
- Bengtsson, Selma, 1984, et al.
(författare)
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A comparative life cycle assessment of marine fuels: liquefied natural gas and three other fossil fuels
- 2011
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Ingår i: Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment. - : SAGE Publications. - 2041-3084 .- 1475-0902. ; 225:2, s. 97-110
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Tidskriftsartikel (refereegranskat)abstract
- Air emissions from shipping have received attention in recent years and the shippingindustry is striving for solutions to reduce their emissions and to comply with stricter regulations.Strategies to reduce emissions can consist of a fuel switch, engine changes, or end-ofpipetechnologies, but they do not necessarily imply reduced life cycle emissions. The presentpaper assesses the environmental performance of marine fuels from well-to-propeller using lifecycle assessment (LCA). Four fossil fuels are compared: heavy fuel oil (HFO), marine gas oil,gas-to-liquid (GTL) fuel, and liquefied natural gas (LNG), combined with two exhaust abatementtechniques: open-loop scrubber and selective catalytic reduction. LNG and other alternativesthat comply with the SECA 2015 and Tier III NOx requirements give decreased acidification andeutrophication potentials with 78–90 per cent in a life cycle perspective compared with HFO. Incontrast, the use of LNG does not decrease the global warming potential by more than 8–20 percent, the amount depending mainly on the magnitude of the methane slip from the gas engine.None of the fossil fuels scrutinized here would decrease the greenhouse gas emissions significantlyfrom a life cycle perspective. The study supports the need for LCA when evaluating theenvironmental impact of a fuel change, e.g. it is found that the highest global warming potentialduring the whole life cycle is connected to the alternatives with GTL fuel.
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| 3. |
- Bengtsson, Selma, 1984, et al.
(författare)
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Fuels for short sea shipping: A comparative assessment with focus on environmental impact
- 2014
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Ingår i: Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment. - : SAGE Publications. - 2041-3084 .- 1475-0902. ; 228:1, s. 44-54
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Tidskriftsartikel (refereegranskat)abstract
- Short sea shipping is facing harder requirements on exhaust emissions in the coming years as stricter regulations are enforced in some regions of the world. In addition, shortage of conventional fuels as well as restrictions on greenhouse gas emissions makes the search for new fuels of interest. The objective of this article is to assess important characteristics to evaluate when selecting fuels for short sea shipping. The following four criteria are considered: (1) local and regional environmental impacts, (2) overall environmental impact, (3) infrastructure and (4) fuel cost and competition with other transport modes. Special focus is put on environmental impact, and life cycle assessment is used for the environmental assessment. The fuels compared in this study are heavy fuel oil, marine gas oil, biomass-to-liquid fuel, rapeseed methyl ester, liquefied natural gas and liquefied biogas. This study shows that liquefied natural gas will reduce the local and regional environmental impacts more relative to the other fuels investigated here. Furthermore, liquefied biogas is found to be the most preferable if all envirtsonmental impact categories are considered. This study also highlights the importance to consider other impact categories for short sea shipping compared to deep sea shipping and shows that NOX emission is the dominant contributor to all assessed environmental impact categories with local and regional impac
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| 4. |
- Burman, Magnus, et al.
(författare)
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Comparative Life Cycle Assessment of the hull of a high-speed craft
- 2016
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Ingår i: Journal of Engineering for the Maritime Environment (Part M). - : Sage Publications. - 1475-0902 .- 2041-3084. ; 230:2, s. 378-387
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Tidskriftsartikel (refereegranskat)abstract
- A comparative Life Cycle Assessment is performed for different structural material concepts on a 24-m-long high-speed patrol craft. The study is comparative and determines the differences in and sensitivities to environmental impact, especially in relation to the total impact of fuel burn for the different material concepts. The material concepts 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. Commercially available standard Life Cycle Assessment software is used for the Life Cycle Assessment calculations. The study shows that regardless of hull material concept, the environmental impact is dominated by the operational phase due to relatively large fuel consumption. In the operational phase, the lightest carbon-fibre concept is shown to have least environmental impact. Considering the manufacturing phase exclusively for the different hull concepts, it is concluded that the manufacturing of the aluminium hull has a somewhat larger environment impact for the majority of Life Cycle Assessment impact categories in comparison to the different composite hulls. The significant impact on the marine and the fresh water aquatic ecotoxicity originates from the aluminium raw material excavation and manufacturing processes. It is shown that the lightest hull, the carbon-fibre sandwich concept, with a 50% structural weight reduction compared to the aluminium design, can be utilized to reduce the fuel consumption by 20% (775 ton of diesel) over the lifetime with significant impact on the dominating environmental aspects considered herein, abiotic depletion, global warming and acidification.
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| 5. |
- Cullinane, Kevin, et al.
(författare)
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A financial evaluation of the design concept for a 'clean energy producing vessel'
- 2015
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Ingår i: Proceedings of the Institution of Mechanical Engineers Part M-Journal of Engineering for the Maritime Environment. - : SAGE Publications. - 1475-0902 .- 2041-3084. ; 229:2, s. 201-217
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Tidskriftsartikel (refereegranskat)abstract
- The design concept for a clean energy producing vessel' proposes the exploitation of remote offshore gas reserves, primarily from stranded fields, using a floating electrical power generation plant. In comparison to conventional approaches utilising liquefied natural gas and pipeline technologies, the clean energy producing vessel represents a highly innovative approach to the production and transportation logistics of natural gas for electricity generation. The main objective of this article is to undertake a financial evaluation of the clean energy producing vessel design concept. This is achieved by developing a financial model comprising cost and revenue modular elements that reflect the major technical components of the design concept: the floating production, storage and offloading unit; the electrical generation plant; cable transmission; carbon capture and electricity prices. The results for net present value and internal rate of return are derived for all combinations of either high- or low-revenue scenarios and for high- or low-cost scenarios. With a rather low internal rate of return of just 15.53%, the only scenario that yields a positive outcome is that of the high-revenue and low-cost combination. Accounting for savings in carbon dioxide emissions exerts only a negligible impact upon the results. Analysis of future research required concludes that following its deployment and implementation, the feasibility of the clean energy producing vessel design concept depends on the outcomes of economic and technological assessments, which are difficult to predict with any degree of certainty.
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| 6. |
- Dashtimanesh, Abbas, et al.
(författare)
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Effects of step configuration on hydrodynamic performance of one- and doubled-stepped planing flat plates : A numerical simulation
- 2020
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Ingår i: Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment. - : SAGE Publications. - 1475-0902 .- 2041-3084. ; 234:1, s. 181-195
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Tidskriftsartikel (refereegranskat)abstract
- Categorized as one of high-speed marine vehicles, stepped planing hulls have the potential to reach relatively high speed in the sea by decreasing wetted surface. There were and still are some challenges in modeling of these vessels and design of ideal situation of steps. In the current study, a numerical-based method has been used to provide understanding about the effect of step height and its location on hydrodynamic characteristics of double-stepped planing plates. At the first step, one-stepped planing plate is numerically simulated. Results are compared against exiting numerical data, suggesting that results of the current numerical simulation are similar to results of previous numerical simulations. Then, double-stepped planing plates are modeled and pressure distribution, wetted length, free surface elevation and drag over lift ratio are computed. It is seen that, ventilation length behind the step and pressure coefficient are increased when step height of one- and a double-stepped planing plates are increased. It has been shown that, unlike an one-stepped planing plate, drag coefficient of a double-stepped planing plate can be increased when the step height is increased. The effects of the location of the second step on the performance of the planing plate have been explored, showing that this position plays a critical role on hydrodynamic forces. It is demonstrated that when the smallest possible lift force is produced by the middle-body, the plate shows the best performance (highest lift over drag ratio).
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| 7. |
- de Alwis, Pahansen, 1980-, et al.
(författare)
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Effect of occupational exposure to shock and vibration on health in high-performance marine craft occupants
- 2021
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Ingår i: Journal of Engineering for the Maritime Environment (Part M). - : SAGE Publications. - 1475-0902 .- 2041-3084. ; 235:2, s. 394-409
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Tidskriftsartikel (refereegranskat)abstract
- Working conditions of High-performance Marine Craft (HPMC) occupants are inherent with shock and vibration. Therefore, HPMC occupants are usually investigated believing that their psychophysical health and performance are negatively affected by exposure to these conditions. However, the association between the regular occupational vibration exposures of HPMC occupants and the deterioration of their health and performance is disputable. Therefore, a sample of HPMC occupants are investigated in a prospective cohort study by measuring perceived work exposure, health and performance via validated web-based questionnaires and physical work exposure as vibration using measurement systems installed onboard their craft. Incidence of musculoskeletal pain (MSP) during four operational seasons is determined and presented as incidence proportion (IP). Association between accumulated vibration exposure aboard HPMC and incidence of MSP is systematically assessed using multiple logistic regression models and expressed as odds ratio (OR). Moreover, the correlation between objectively and subjectively measured vibration exposures is determined using the Spearman’s rank correlation coefficient (rs). Incidence proportion of neck pain was 63.4% and that of lower back pain ranged from 12.5% to 87.5% over the four seasons. The accumulated vibration exposure was strongly associated with the incidence of MSP primarily with lower back pain. However, the association was not statistically significant. The objective and subjective vibration exposures of the craft drivers showed a statistically significant positive monotonic correlation. The study suggests that occupational exposure to shock and vibration aboard HPMC is a factor increasing the incidence of MSP. The HPMC occupants regularly experience attrition in their performance. The perceived vibration exposure of the drivers can be used to rank the exposure severity aboard HPMC in the absence of objective measurements. The current vibration exposure assessment methods are also recommended to be revised accounting for shock and vibration inherent in HPMC exposures.
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| 8. |
- de Alwis, Pahansen, 1980-, et al.
(författare)
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Exposure aboard high-performance Marine craft increases musculoskeletal pain and lowers contemporary work capacity of the occupants
- 2021
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Ingår i: Journal of Engineering for the Maritime Environment (Part M). - : SAGE Publications. - 1475-0902 .- 2041-3084. ; 235:3, s. 750-762
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Tidskriftsartikel (refereegranskat)abstract
- High-Performance Marine Craft (HPMC) occupants are currently being investigated for various psychophysical impairments degrading work performance postulating that these deteriorations are related to their occupational exposures. However, scientific evidence for this is lacking and the association of exposure conditions aboard HPMC with adverse health and performance effects is unknown. Therefore, the study estimates the prevalence of musculoskeletal pain (MSP) among HPMC occupants and the association of their work exposure with MSP and performance degradation. It also presents a criterion for evaluating the self-reported exposure severity aboard three different types of mono-hull HPMC; displacement, semi-displacement and planing, on a par with the available standard criteria for objectively measurable exposures. Furthermore, another criterion is proposed to assess the performance-degradation of HPMC occupants based on self-reported fatigue symptoms and MSP. Swedish Coast Guard HPMC occupants were surveyed for MSP, fatigue symptoms as well as for work-related and individual risk indicators using a validated web-based questionnaire. Prevalence of MSP and performance-degradation during the past 12 months were assessed and presented as a percentage of the sample. Associations of exposure conditions aboard HPMC with MSP and performance-capacity were systematically evaluated using multiple logistic regression models and expressed as odds ratio (OR). Prevalence of MSP was 72% among which lower back pain was the most prevalent (46%) followed by neck pain (29%) and shoulder pain (23%) while 29% with degraded performance. Exposure to severe conditions aboard semi-displacement craft was associated with lower back (OR = 2.3) and shoulder (OR = 2.6) pain while severe conditions aboard planing craft with neck pain (OR = 2.3) and performance-degradation (OR = 2.6). MSP is common among Swedish coast guards. Severe exposure conditions aboard HPMC are significantly associated with both MSP and performance-degradation. The spine and shoulders are the most susceptible to work-related MSP among HPMC occupants which should be targeted in work-related preventive and corrective measures.
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| 9. |
- de Alwis, Pahansen, 1980-, et al.
(författare)
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Monitoring and characterization of vibration and shock conditions aboard high-performance marine craft
- 2018
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Ingår i: Journal of Engineering for the Maritime Environment (Part M). - UK : Institution of Mechanical Engineers. - 1475-0902 .- 2041-3084. ; 233:4, s. 1068-1081
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Tidskriftsartikel (refereegranskat)abstract
- The stochastic environmental conditions together with craft design and operational characteristics make it difficult to predict the vibration environments aboard high-performance marine craft, particularly the risk of impact acceleration events and the shock component of the exposure often being associated with structural failure and human injuries. The different timescales and the magnitudes involved complicate the real-time analysis of vibration and shock conditions aboard these craft. The article introduces a new measure, severity index, indicating the risk of severe impact acceleration, and proposes a method for real-time feedback on the severity of impact exposure together with accumulated vibration exposure. The method analyzes the immediate 60s of vibration exposure history and computes the severity of impact exposure as for the present state based on severity index. The severity index probes the characteristic of the present acceleration stochastic process, that is, the risk of an upcoming heavy impact, and serves as an alert to the crew. The accumulated vibration exposure, important for mapping and logging the crew exposure, is determined by the ISO 2631:1997 vibration dose value. The severity due to the impact and accumulated vibration exposure is communicated to the crew every second as a color-coded indicator: green, yellow and red, representing low, medium and high, based on defined impact and dose limits. The severity index and feedback method are developed and validated by a data set of 27 three-hour simulations of a planning craft in irregular waves and verified for its feasibility in real-world applications by full-scale acceleration data recorded aboard high-speed planing craft in operation.
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| 10. |
- Evegren, Franz, 1984-, et al.
(författare)
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Fire safety regulations and performance of fibre-reinforced polymer composite ship structures
- 2017
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Ingår i: Journal of Engineering for the Maritime Environment (Part M). - : SAGE Publications. - 1475-0902 .- 2041-3084. ; 231:1, s. 46-56
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a procedure for how to relate fire performance of fibre reinforced polymer (FRP) composite structures to the fire safety regulations in SOLAS II-2. It can be used as basis when performing a fire risk assessment to demonstrate that the degree of safety is at least equivalent to that provided by prescriptive requirements. A key issue is that requirements and test methods are based on a use of steel structures, which requires seeking the safety level implied by the regulations. This was demonstrated for the regulations and introduced hazards affecting the growth stage of a fire. The safety implied by regulations was related to fire performance of FRP composite by reference to fire tests involving typical materials and some relevant safety measures. Ignition was described as uncritical whilst the fire growth on an FRP composite surface can be rapid. Flammability requirements are generally not achieved by an untreated panel but different means can be used for protection. A fire protective coating can be used to prevent ignition and sprinkler is effective both for fire prevention and extinguishment on interior and external surfaces. For interior spaces it can be relevant with a coating or thermal insulation also to hinder increased generation of smoke and toxic gases during fire evacuation. In total it is shown that fire hazards during the fire growth stage are manageable and a foundation is lain out for a well-structured fire risk assessment.
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