| 1. |
- Johansson, Bengt, 1966-, et al.
(författare)
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Vatten- och avloppsinstallationer : en kunskapssammanställning
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna kunskapssammanställning om vatten- och avloppsinstallationer i Sverige kan ge en bred och korrekt förståelse om branschens aktörer, vilka regler som tillämpas, var det finns kunskap och vilka utvecklingsbehov som behöver stödjas. Några viktiga punkter är:Legionella – finns i tappvattensystem och orsakar ohälsa. Begränsning av risker behöver utredas vidare inte mot bakgrund av risker med förväntade högre temperaturer och önskemål om att ta fram system för med lägre energiförbrukning för varmvatten. Risk för legionella i kallvatten finns också.Utformning och placering av rörkopplingar – har stor betydelse för beständighet hos installationer och möjlighet att upptäcka och hantera läckage. Regler och vägledningar som utvecklats över tid har möjliggjort den goda standarden på vatten- och avloppsinstallationer vi har idag.Dimensionering av system – komponenter och flöden samverkar i samma system. Därför finns risker om en komponent eller ett delsystem optimeras av något skäl utan att konsekvenserna för hela förstås. Spillvattensystem är t.ex. beroende av flöden för tappdricksvatten.Det är viktigt att ta med sig förvärvade kunskaper och lärdomar för att undvika problem som tidigare visats sig vara kostsamma. Det gäller i synnerhet för system som installeras dolt, och som förväntas ha en livslängd på flera decennier.Ett regelverk som tar hänsyn till de problem som har lösts genom åren, och som ger goda förutsättningar att förebygga framtida problem, kommer att gynna den som bor eller vistas i byggnaden, den som äger byggnaden, den som bygger eller installerar, den som levererar byggprodukterna och den som försäkrar byggnaden. Det är även bra ur ett hållbarhetsperspektiv, eftersom lång problemfri livslängd oftast minskar miljöbelastningen.
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| 2. |
- Kuzmin, Leonid
(författare)
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Interfacial kinetic ski friction
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- It is no doubt, that the ski glide over the snow is a very complicated object of research. However, ski glide is just a one area of many other areas of human knowledge. As a rule, the scientists and practitioners, who work in these areas, operate with some publicly expressed more or less solid hypotheses. These researchers work with one hypothesis until another and a better one comes up. Our literature studies and our own observations regarding modern skis preparations, did not give us any solid hypotheses, which are able to explain the actual form and content of this procedure. The present work is an attempt to reveal such hypotheses. Conclusion: To achieve an optimal glide on skis with the base (the ski sole) made of some high hydrophobic durable polymer, e.g. UHMWPE, PTFE; we only have to create an adequate topography (texture) on the ski running surface, adequate to the actual snow conditions.
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| 3. |
- Jonsson, Carl-Johan, et al.
(författare)
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A case-based reasoning method including tooling function for case retrieval and reuse in stamping tooling design
- 2023
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Ingår i: Computer-Aided Design and Applications. - : CAD solutions. - 1686-4360. ; 20:5, s. 839-855
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Tidskriftsartikel (refereegranskat)abstract
- Design of sheet metal forming tooling is currently based on that experienced tooling designers with good knowledge of how stamping tools previously have been designed and operated in production, apply their knowledge when making a new design. For retrieving former designs, they often need to rely on their good memory. In this paper, an automatic method for retrieving relevant former cases is presented. A major challenge is defining the similarity between the current and the former cases i.e., finding the relevant parameters to include in the CBR (Case-based reasoning) search. This is here addressed by using CAD model parameters both from former components and the tooling for their production. By interviewing tooling designers in industry, a set of relevant parameters has been identified. To arrive at the correct weight of each parameter, a genetic algorithm has been used to optimize the search results. This resulted in a quick and automated way of retrieving the most relevant former cases and presenting them to the designer. The method has been tested on actual cases with promising results. This has the potential of making sheet metal part and tooling design less reliant on memory and experience.
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| 4. |
- Jonsson, Carl-Johan, et al.
(författare)
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Design knowledge reuse in design of progressive stamping tools : A qualitative study
- 2021
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Ingår i: Proceedings of the Design Society , Volume 1 , August 2021. - : Cambridge University Press. ; , s. 1053-1062
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Konferensbidrag (refereegranskat)abstract
- Progressive stamping tools are widely used in mass-production of sheet metal components and their performance is critical as the design of the tool impact the cost of the manufactured component significantly. Knowledge reuse is an important part of successful design in general, and in progressive stamping tool design in particular. In the study described in this paper, 8 tool designers from 5 different Swedish companies were interviewed about (1) at what points in the tool design process they search for previously designed tools for information and knowledge reuse, (2) under what conditions and for what reasons does this reuse take place, and (3) what types of information and knowledge are sought for at each point. The results show that reuse of information and knowledge from previously designed tools happens in many parts of the tool design process. The reasons and conditions for reuse vary depending on where in the process the designer is. High component complexity is one example of a common factor triggering reuse. Also, information about the performance of the tool is important to tool designers, as they only want to reuse information and knowledge from tools with good performance and low maintenance.
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| 5. |
- Jonsson, Carl-Johan, et al.
(författare)
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Method for Task-based Model Retrieval for Reuse in Stamping Tool Design
- 2022
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Ingår i: CAD'22 Proceedings. ; , s. 189-193
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Konferensbidrag (refereegranskat)abstract
- Introduction: Shorter lead-times are a constant driver for improving efficiency in the design and manufacturing of stamping tools for sheet metal components. Finding and reusing past solutions in design is an important way for improving efficiency and quality in stamping tool development. This can be done in the form of retrieving CAD-models of relevant past tooling designs. This type of knowledge reuse is standard practice among tool designers through remembering past problems, and solutions from previous projects, or having a collection of good examples of tools of different varieties, to reuse solutions from. Automatically indexing and retrieving relevant CAD-models of the tools can enable the tool designers to conduct the search more systematically and automatically. Retrieving relevant similar CAD-models automatically, however, has some challenges regarding how similarity should be defined, as geometric similarity is ill-defined [4]. A relevant metric of similarity depends on the application context, the objective, and what knowledge that the designer is searching for [3].In this work, focus is on variations in the different use cases and situations of the stamping tool design process. The existing work done in the application to stamping tools has provided retrieval mechanisms for blanking dies [1], deep drawn features [6], and overall similarity [5]. In the stamping tool design process, the information and knowledge sought for at different stages are different in nature [2] and require individual similarity metrics and parameters to be effective. An example of this is that, the relevant CAD-models to retrieve when designing the functionality for part ejection from the tool is different from the relevant models when designing forming dies of the same tool.
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| 6. |
- Jonsson, Carl-Johan, et al.
(författare)
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Stamping tools for sheet metal forming : Current state and future research directions
- 2020
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Ingår i: Transdisciplinary engineering for complex socio-technical systems – Real-life applications. - Clifton, VA : IOS Press. - 9781643681108 - 9781643681115 ; , s. 281-290
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Konferensbidrag (refereegranskat)abstract
- Sheet metal forming tools play an important role in the manufacturing of many products. With shorter product life cycles and demand for shorter time to market for new products, the process for design and manufacturing of stamping tools becomes a critical part. Stamping dies are often designed and manufactured by smaller, specialized companies. For a tooling company, knowledge and experience is an important competitive advantage. Traditionally the design process has been characterized by being based on few key individuals with much experience and craftsmanship. To stay competitive in this market there is a need for more efficient processes, systems, tools and supports in order to become more industrialized. This paper presents results from a study of the state of practice in industry within progressive stamping tool design as well as a review of relevant literature. The design and manufacturing processes for stamping dies in six companies have been investigated through semi-structured interviews, from which the main challenges in the current state for the companies are identified. The results from the interviews was analyzed and compared to the established concepts and frameworks of methods found in the literature review. The results and analysis points in the direction of efforts needed in supporting the formalization and reuse of information and knowledge from previous tool projects and production, especially during the critical steps of tool process planning and creating the tool layout.
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| 7. |
- Jonsson, Roland, et al.
(författare)
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Multi-Target tracking with background discrimination using PHD filters
- 2012
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Ingår i: Proceedings of the 15th International Conference on Information Fusion.
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose a new double PHD filter for simultaneous multi-target tracking and background discrim- ination for airborne radar applications. Both the foreground and the background processes are modeled as Poisson point processes, which gives a symmetric formulation of the coupled filters. The differences between foreground and background lie in the assumed target dynamics, and in the sensor detection probabilities. Although there are proposals for PHD filter with adaptive background models in the literature, our filter appears to be novel and also the simplest possible. To implement the filter we use a Gaussian mixture approximation of the intensities, which enables simple and effective ways to extract tracks. For the evaluations we use a simulated target tracking scenario with an airborne radar tracking a number of flying targets over a background of road objects. First, the performance of the Gaussian mixture PHD filter with track extraction is illustrated. Second, the superior ability of the foreground-background PHD filter to suppress clutter and disturbing road traffic is illustrated.
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| 8. |
- Lord, John, et al.
(författare)
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The Luleå ball and disc apparatus
- 2001
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Ingår i: Bench testing of industrial fluid lubrication and wear properties used in machinery applications. - West Conshohocken, Pa : ASTM International. - 0803128673 ; , s. 53-67
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Konferensbidrag (refereegranskat)abstract
- The ability to measure lubricant film thickness in elastohydrodynamic point contacts was greatly improved when the method of interferometry was introduced in the late 1960s. Constant refinements of the technique have made it possible to measure the thickness of thin films with an accuracy of a few nanometers. In order to further develop the technique and provide a tool for advanced lubricant experiments, a Ball and Disc Apparatus was developed. The aim was to accomplish an apparatus with an open architecture for easy expansion and the ability to use several sub-methods for film thickness determination.
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