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Visar resultat 1 - 5 av 331 avhandlingar som matchar ovanstående sökkriterier.

1. 1. On wear in rolling/sliding contacts

   Författare :Rickard Nilsson; Ulf Olofsson; I. Sherrington; KTH; []
   Nyckelord :Technology; wear; rolling; sliding; contact; environment; TEKNIKVETENSKAP; TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : The aim of this thesis is to increase the understanding of wear in rolling/sliding contacts such as the wheel-rail contact for railroads and the roller-washer contact for roller bearings. The Stockholm commuter train network has been the subject of papers A and B in this thesis in which the wear and surface cracks on rails has been observed for a period of three years. LÄS MER

3. 2. Modelling calving and sliding of Svalbard outlet glaciers : Spatio-temporal changes and interactions

   Författare :Dorothée Vallot; Rickard Pettersson; Veijo Pohjola; Ken Mattsson; Tómas Jóhannesson; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cryospheric science; glacier modelling; time-lapse imagery; undercutting; sliding inversion; discrete particle model; calving model; subglacial hydrology; sliding law; automatic detection method; calving events size and frequency; ocean interaction; melt water runoff; ice dynamics; ice flow model; Geovetenskap med inriktning mot naturgeografi; Earth Science with specialization in Physical Geography;

   Sammanfattning : Future sea level rise associated to global warming is one of the greatest societal and environmental challenges of tomorrow. A large part of the contribution comes from glaciers and ice sheets discharging ice and meltwater into the ocean and the recent worldwide increase is worrying. LÄS MER

4. 3. Minimum-time sliding mode control of robot manipulators

   Författare :Boyko Iliev; Ivan Kalaykov; Krzysztof Kozlowski; Örebro universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Reglerteknik; minimum-time sliding mode control; sliding mode control; maximum-slope sliding lines; Takagi-Sugeno fuzzy systems; robot manipulators; reglerteknik; Automatic control; Reglerteknik; Reglerteknik; Automatic Control;

   Sammanfattning : Robot manipulators have a complex and highly nonlinear dynamics, accompanied with a high degree of uncertainty. These properties make them difficult for time-optimal control. The theory of sliding mode control can provide methods, able to cope with the uncertainty and nonlinearity in the system. LÄS MER

5. 4. A study on wear characteristics of high strength steels under sliding contact

   Författare :Abdulbaset Mussa; Pavel Krakhmalev; Jens Bergström; Jens Hardell; Karlstads universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; High strength steels; thread joint wear; punch wear; sliding wear; surface cracking; reciprocal sliding; fatigue; surface delamination; white etching layer; nano-structured layer; friction; Materialteknik; Materials Engineering;

   Sammanfattning : In the last decades, significant improvements regarding the design, materials and technology of rock drills have been made. Likewise, in sheet metal forming, forming tools experience very high contact pressures when processing high strength steel sheets. LÄS MER

7. 5. Tribology of self-lubricating polymer composites for hydropower applications

   Författare :Maria Rodiouchkina; Jens Hardell; Kim Berglund; Jan Ukonsaari; Michał Wasilczuk; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; polymer composites; hydropower; sliding wear; sliding friction; self-lubricating; transfer layers; material characterization; surface analysis; high contact pressure; low sliding speed; Machine Elements; Maskinelement;

   Sammanfattning : The ongoing global climate crisis and its impacts calls for urgent actions, such as significant reduction of CO2 emissions by introducing more renewable energy. This has led to a rapid integration of variable power sources, such as wind and solar power, into the electricity systems. LÄS MER