| 1. |
- Marimon Giovannetti, Laura, et al.
(författare)
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The effects of hydrodynamic forces on maneuvrability coefficients for wind-assisted ships
- 2020
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Ingår i: ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering (OMAE2020). - 9780791884379
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Konferensbidrag (refereegranskat)abstract
- Assessing the manoeuvring performances of a ship at a design stage is becoming more important, especially when trying to improve shipping efficiency to reduce fuel consumption. When designing a hull with appendages, it is necessary to balance hydrodynamic efficiency with manoeuvrability. Therefore, the possibility of simulating a captive test at a design stage will increase the chances of understanding the behaviour of a ship from an early stage in the design process. The current research is based on the evaluation of hydrodynamic efficiency of a hull and appendages in a pure resistance, self-propulsion and in a wind-assisted mode. The forces and moments acting on the hull and appendages are then analysed and used as inputs for a Virtual Captive Test (VCT) [1]. In order to correctly perform a VCT and further analyse the performances of a ship with a Velocity Prediction Programme (VPP), particular care has been put in correctly capturing the manoeuvrability coefficients. Those are derived with polynomial fittings once the forces and moments acting on the ship are extracted from the Computational Fluid Dynamics (CFD) simulations. Many CFD simulations were performed to assess the hydrodynamic characteristics of the hull and appendages in a range of flow directions, rudder angles and rotating flow. Those simulations encompass the whole range of datapoints needed to describe a wind-assisted ship during manoeuvring. Taking into consideration both hydrodynamic characteristics and manoeuvrability effects at an early design stage can reduce model tests costs and will allow to inspect a larger number of hull-appendages scenarios when analysing the final VPP results.
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| 2. |
- Olsson, Fredrik, et al.
(författare)
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A Performance Depowering Investigation for Wind Powered Cargo Ships Along a Route
- 2020
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Ingår i: Journal of Sailing Technology. - : The Society of Naval Architects and Marine Engineers. - 2475-370X. ; 5:1, s. 47-60
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Tidskriftsartikel (refereegranskat)abstract
- For a sailing yacht, depowering is a set of strategies used to limit the sail force magnitude by intentionally moving away from the point of maximum forward driving force, potentially reducing the ship speed. The reasons for doing this includes among others; reduction of quasi-static heeling angle, structural integrity of masts and sails and crew comfort. For a wind powered cargo ship, time spent on a route is of utmost importance. This leads to the question whether there is a performance difference between different depowering strategies and if so, how large. In this research, a wind-powered cargo vessel with rigid wings is described in a Velocity Prediction Program (VPP) with four-degrees of freedom, namely surge, sway, roll and yaw, with a maximum heel angle constraint. The resulting ship speed performance for different depowering strategies are investigated and the implications in roll and pitch-moments are discussed. The wind conditions when depowering is needed are identified. A statistical analysis on the probability of occurrence of these conditions and the impact of the different depowering strategies on the required number of days for a round-trip on a Transatlantic route is performed.
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| 3. |
- Svanberg, Martin, 1982, et al.
(författare)
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Analyzing animal waste-to-energy supply chains: The case of horse manure
- 2018
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Ingår i: Renewable Energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 129, s. 830-837
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Tidskriftsartikel (refereegranskat)abstract
- To reduce human impact upon the environment, a transition from fossil to renewable energy sources such as biomass is imperative. Biomass from animal waste such as horse manure has unutilized potential as it has yet to be implemented at a large scale as an energy source. Research has demonstrated the technical feasibility of using animal waste for energy conversion, though their supply chain cost poses a barrier, as does a gap in research regarding the specific design of efficient horse manure-to-energy supply chains. In response, we investigated the design of horse manure-to-energy supply chains through interviews and site visits at stables, as well as through interviews with transport companies. Our findings show that horse manure-to-energy supply chains have distinct attributes at all stages of the supply chain such as the geographical spread of stables that determines supply chain design and hampers efficiency. They share several such attributes with forest biomass-to-energy supply chains, from which important needs can be identified, including the industrial development of trucks dedicated to the purpose, mathematical modeling to handle the trade-off of cost of substance loss in storage and cost of transport, and business models that reconcile the conflicting goals of different actors along the supply chains. (C) 2017 Elsevier Ltd. All rights reserved.
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| 4. |
- Svanberg, Martin, 1982, et al.
(författare)
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Logistics issues in manure-to-energy supply chains
- 2016
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Ingår i: 1st International Conference on Bioresource Technology for Bioenergy, Bioproducts & Environmental Sustainability, 23-26 October 2016, Sitges, Barcelona, Spain. - : 1st International Conference on Bioresource Technology for Bioenergy, Bioproducts & Environmental Sustainability, 23-26 October 2016, Sitges, Barcelona, Spain.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Waller, William H., et al.
(författare)
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FM14 Session 2: Communicating Astronomy in our Changing World
- 2018
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Ingår i: Proceedings of the International Astronomical Union. - : Cambridge University Press. - 1743-9213 .- 1743-9221. ; 14:A30, s. 528-530
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Tidskriftsartikel (refereegranskat)abstract
- As the IAU heads towards its second century, many changes have simultaneously transformed Astronomy and the human condition world-wide. Amid the amazing recent discoveries of exoplanets, primeval galaxies, and gravitational radiation, the human condition on Earth has become blazingly interconnected, yet beset with ever-increasing problems of over-population, pollution, and never-ending wars. Fossil-fueled global climate change has begun to yield perilous consequences. And the displacement of people from war-torn nations has reached levels not seen since World War II. © International Astronomical Union 2020.
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| 6. |
- Andersson, Anton, et al.
(författare)
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Design of a Foiling Optimist
- 2018
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Ingår i: Journal of Sailboat Technology. ; 2018, s. 1-24
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Tidskriftsartikel (refereegranskat)abstract
- Because of the successful application of hydrofoils on the America's Cup catamarans in the past two campaigns the interest in foiling sailing craft has boosted. Foils have been fitted to a large number of yachts with great success, ranging from dinghies to ocean racers. An interesting question is whether one of the slowest racing boats in the world, the Optimist dinghy, can foil, and if so, at what minimum wind speed. The present paper presents a comprehensive design campaign to answer the two questions. The campaign includes a newly developed Velocity Prediction Program (VPP) for foiling/non-foiling conditions, a wind tunnel test of sail aerodynamics, a towing tank test of hull hydrodynamics and a large number of numerical predictions of foil characteristics. An optimum foil configuration is developed and towing tank tested with satisfactory results. The final proof of the concept is a successful on the water test with stable foiling at a speed of 12 knots.
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| 7. |
- Andersson, A, et al.
(författare)
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The Foiling Optimist
- 2017
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Ingår i: The Proceedings of the 4th International Conference on Innovation in High Performance Sailing Yachts, Lorient, France, 28-30 June 2017.. ; , s. 19-30
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Konferensbidrag (refereegranskat)
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| 8. |
- Brynzér, Henrik, et al.
(författare)
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Sustainability and cost efficiency in Supply Chains
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The project was formed from three basic observations, which together considerably alter the requirements when designing the supply chains. First, the lean production deployment is now ruling the design of the work cells, e.g. the assembly stations. Second, the focus on sustainability and environmental consideration is calling for new models when designing the supply chains, and third, great cost and time reduction potentials are revealed in the supply chains when applying value stream mapping. The purpose of the project was to contribute to the understanding and to the methods of how to design and evaluate sustainable and cost efficient supply chains that supports lean production processes. The project involved all industrial actors of the FFI programme and relied to a large extent on case studies performed in the companies. These cases often combined the development of models and methods with testing and pilot implementations at the companies. Results were disseminated among the actors through workshops and seminars, which further strengthened the results and understanding of applicability. Among the theoretical contributions is the development of the concept of material exposure, as an interface between materials supply and assembly. This interface realizes the product of the material supply system in the form of an available component for the assembly system to assemble, given the requirements of the customer in form of the assembly system. These requirements govern how material exposure is realized and provides a framework for how materials supply systems can be designed. In this way, the principles of lean production in the assembly is supported by the material supply, while allowing the development of a material supply system that itself is lean.One case study investigated systems for repacking of material between packaging types, that may be necessary to meet the requirements of the assembly system at the same time as the transport costs are kept down. From the case study, a classification of compo¬nents that can be handled manually in this type of repacking were derived, and five different types of components were identified. The case study conclusions include the time to pick these components between different packaging types. These results have been put into further work in the case study company, regarding designing systems for repacking of material.A theoretical model was developed to compare how the choice of packaging affect cost and CO_2 emissions for the supply of materials. A case study chose to compare two different packages with fundamentally different characteristics, one of which was a conventional returnable packaging based on plastics and the other a disposable one-way packaging. In this case the disposable packaging turned out to be clearly advantageous from both a cost and an environmental perspective.A new methodology to describe and evaluate the fulfilment of requirements of material flows was developed within the sub-project ‘Materials Flow Mapping’. This methodol¬ogy provides the ability to better, and in more detail, study material flows and its activi¬ties. Such a level of detail in the analysis proved valuable as a basis for improvement work in the materials supply system, where there is a need to be able to describe the often non-value-added activities that occur.One sub-project was carried out with the aim of developing a cost model for estimating the cost of packaging, transport and in-plant logistics in a supply chain from suppliers to assembly, and to implement this in a software. This is an important contribution to the development of a decision tool for the selection of materials supply set up. The model represents a comparatively fast tool for obtaining cost estimates of various configura¬tions of the materials supply system.Finally, one sub-project has treated materials control, to support the research being done on the physical flows. The focus has been on pull-based materials planning with consid-eration to man, technology and organization (MTO), a need that was identified during the project. The result is two-fold, the first part being a model consisting of MTO factors that are important to take into account in the design and implementation phase of a pull-based system. Secondly, research has provided a better understanding of the potential problems during a process of implementing an external pull system and classified these problems based on the MTO dimensions.
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| 9. |
- Daun, Viktor, et al.
(författare)
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Demonstrating the use of urban and inland waterways – for densely populated cities and more sustainable transport
- 2017
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Ingår i: SSPA Highlights. ; 64, s. 8-11
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Demonstrating new logistics solutions is shown to be an important step for gaining understanding of system prerequisites for commercialisation, both with regard to technical issues such as vessel design characteristics and cargo handling equipment, and social matters such as the importance of practitioner involvement and the evaluation of performance criteria. SSPA demonstrated the use of urban and inland waterways as part of two large collaboration projects: DenCity and NÖKS II. This is a promising path for the future, both for managing the trend towards more densely populated cities and for using more sustainable transport solutions.
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| 10. |
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