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- Christina, Keller, 1961-, et al.
(författare)
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Structured knowledge transfer through online education : Mutual benefits for academia and industry
- 2016
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Konferensbidrag (refereegranskat)abstract
- Scientists are required to disseminate the results of research to the society and companies participating in research projects. The dissemination procedure normally consists of seminars, scientific and layman journal contributions, and conferences that generally are not flexible and timely enought to capture industrial needs. In an effort to accelerate knowledge transfer and technology implementation to sustain and improve competitiveness, Jönköping University has developed a one-year online master programme in cast metals and processes in collaboration with the industry. The collaboration includes development of the curriculum, case studies, lectures and study visits. To explore the development process, we performed interviews and a survey with participating students/professionals, teachers and industrial partners. Our results show that a profound two-way knowledge transfer took place, and that course content and teaching were highly relevant to the industry. Furthermore, industry and academia engaged in new joint research collaborations. Consequently, we hypothesize that the procedure for structured knowledge transfer can be implemented in materials education at advanced level to foster engagement between university, industry and society.
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| 2. |
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| 3. |
- Sjögren, Torsten, et al.
(författare)
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Comparison of Mechanical Properties in Flake Graphite and Compacted Graphite Cast Irons for Piston Rings
- 2004
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Ingår i: International Journal of Cast Metals Research. - : Maney Publishing. - 1364-0461 .- 1743-1336. ; 17:2, s. 65-71
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Tidskriftsartikel (refereegranskat)abstract
- Cast iron is often used as the piston ring material in marine diesel engines. The mechanical properties of cast irons are to a great extent governed by the size, distribution and shape of the incorporated graphite particles. In a set of experiments, the mechanical properties of a pearlitic grey cast iron and a pearlitic compacted graphite cast iron are compared. Both cast iron grades have a eutectic composition. The experiments confirm the importance of micro-yielding of the matrix at the tip of the graphite particles on the macroelastic behaviour of the studied cast irons. This applies especially for the flake graphite cast iron where the graphite tip is sharper and the matrix bridges between the graphite particles are shorter than in the case of the compacted graphite cast iron resulting in micro-yielding at the graphite tip at a very low macro-stress and macro-strain. The high local stresses at the graphite tips also result in the opening of the graphite cavities which is much more severe in the flake graphite cast iron than in the compacted graphite cast iron. The mechanical properties of the eutectic flake graphite cast iron are largely affected by the size and amount of the graphite particles. The smaller the graphite particles (faster solidification) in the microstructure, the lower the values of the mechanical properties. In compacted graphite cast iron, the macro-elastic behaviour is influenced by the matrix and the overall coarseness of the microstructure to a greater extent and the effect of the incorporated graphite particle size is much less pronounced.
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| 4. |
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| 5. |
- Sjögren, Torsten, et al.
(författare)
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High Performance Piston Rings for Two-Stroke Marine Diesel Engines
- 2004
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Ingår i: Proceedings // 24th CIMAC World Congress on Combustion Engine Technology.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The piston ring is a key component in a marine combustion engine. High mechanical loads, relatively high temperatures and corrosive gases and liquids influence its performance in terms of sealing capacity, wear of cylinder liner and the ring itself. Base material of the ring, coating technology and ring geometry design are discussed in the article.When tailoring cast iron materials suitable as piston ring base material two parameters are of importance; the morphology of the graphite and the constituents of the matrix. To optimize the properties of the cast iron a compromise is needed to achieve a satisfactory performance of the piston rings.Daros Piston Rings AB is currently developing a second generation of chromium-ceramic coating the so called Z-chrome. The objective of this project has been to increase the maximum operating temperature of the coating and leave the other characteristics of the coating unaffected. The difference between the commercial Daros coating Tritor® and the Z-chrome is the ceramic component included in the coated layer.Insufficient conformability of piston ring and liner geometry may produce a large local cylinder wall pressure which will destroy the oil film leading to uncontrolled wear and scuffing. Lack of conformability can also produce leakage paths for the combustion gases. Therefore a correct ring shape is of utmost importance. A new design philosophy designated OPCORE® has been developed and is presented here.
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| 6. |
- Vomacka, Peter
(författare)
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Crystallization of glasses in the system (Zr)-Y-Si-Al-O-(N)
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Glass is a group of materials that has been used for structural and functional purposes for many centuries. Nevertheless, interest in the science and technology of glass has expanded significantly in recent years as a result of the need to develop new materials for advanced applications. Examples of new materials in which glasses of various kinds are an essential constituent include glass ceramics which are prepared by crystallizing glass, glass matrix composities, glass fibre reinforced composities and optical-fibre glass. Sintered covalent ceramics, used for example for wear resistance and high temperature applications often also contain a small proportion of glass phase which is added intentionally to aid densification during sintering. In the development of such materials it has proved necessary to widen knowledge of the physical, chemical and mechanical properties of glass and how these are influenced by composition and microstructural morphology. The aim of the work presented in this thesis is to develop a better understanding of the crystallization behaviour of glasses in the system YSi-Al-0-(N) with small additions of ZrO2 as a nucleating agent. Interest in the Y-Si-Al-0-(N) system stems not only from the fact that it forms the basis of glass phases added as sintering aids found as microstructural constituents in sintered Si3N4-based ceramics but also because glasses in this system have potential to form a relatively new group of refractory glass-ceramics. The study of compositions within this system in this work has involved investigation of: the glass formation in the Al2O3-Y2O3-Si02 system under conditions of laser melting; the crystallization behaviour and properties of selected oxide and oxynitride glasses with / without addition of zirconia; the role of zirconia addition on the crystallization behaviour of Y-Si-Al-0-(N) glasses and on the melting of Y-Si-Al-0-(N) glass-ceramics; the YAG crystallization from an oxynitride glass relevant to the improved heat treatment of YAG-based glass-ceramics and YAG/beta-SiAlON materials. Techniques used in the investigations involved laser glass melting, conventional furnace glass melting, glass-ceramic furnace heat treatment, scanning electron microscopy, room temperature X-ray diffractometry, high temperature X-ray diffractometry, differential thermal analysis, differential scanning calorimetry, dilatometry, infrared spectroscopy, Vickers hardness and density measurements. The glass-forming region in the system Y2O3-Al2O3-SiO2 under conditions of laser melting was found to be more extensive than in earlier studies. No glass formed in compositions with less than 20 wt % SiO2. 6 wt % of ZrO2 can be dissolved in the investigated composition of the yttria-alumina-silica liquid at 1700°C. When larger amounts are added a cubic crystalline phase of "yttria-stabilized zirconia" with a composition of Y0.15Zr0.8501.9 forms. The hardness and density of the zirconia-containing glasses are slightly higher than for the zirconiafree glasses. The glass transition temperature and softening temperature are lowered by the addition of zirconia. The Zr4+ cation acts as a glass-network modifier causing lowering of the viscosity of the glass with a consequent decrease of the nucleation density. The optimum nucleation temperature of the ZrO2-containing glasses is marginally lower than that of the ZrO2-free glass. ZrO2 acts as a crystal growth modifier rather than a nucleating agent during the crystallization of the ZrO2-containing glasses. Addition of ZrO2 promotes the formation of the y-Y2Si2O7 phase. Due to the lower viscosity of the retained glass in the ZrO2-containing glass-ceramics the rates of the phase transformations involved in the melting process are increased. The YAG crystallization from a ZrO2-free oxynitride glass was studied by high temperature X-ray diffractometry. It was found that the crystallization occurred preferably at free surfaces.
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