Search results for "53"
showing 10 items of 2908 documents
Modelling of a hydro-pneumatic system for heave compensation
2017
Masteroppgave i mekatronikk MAS500 - Universitetet i Agder 2017 Testing of control systems on simulators has been found to be both cost and time e cient. To get good results from testing, a realistic response from the simulator is important. In this thesis, a mathematical model of a hydropneumatic heave compensation system for such purposes is proposed. The emphasis has been on developing a relatively simple model which is easy to run, but also accounts for important e ects like friction, non-ideal gas behaviour and temperature variation in the gas system. The mathematical model is veri ed against log data obtained from real drilling operations. Then, it is compared to simpler versions to i…
Secondary Control of a Digital Hydraulic Motor for Winch Applications
2018
Master's thesis Mechatronics MAS500 - University of Agder 2018 The reliable traditional hydraulic systems for industrial purposes is being challenged by an emerging technology called digital hydraulics. This technology shows promising improvements in regards to e ciency, especially in comparison to systems dependent on hydraulic pumps or motors with variable displacement. Digital hydraulic motors eliminate the need for a servo valve by connecting each individual motor cylinder directly to the high-pressure and low-pressure line by means of fast-acting on/o -valves. In this thesis, the potential of digital hydraulics is investigated by developing a control system intended for a digital displ…
Fault Diagnosis of an Electrical Winch based on Structural Analysis
2018
Master's thesis Mechatronics MAS500 - University of Agder 2018 This report covers development and implementation of a model-based fault-detection and fault diagnosis algorithm based on structural analysis, providing deeper knowledge of predictive maintenance, which o ers the industry increased uptime and reduced spending. Failure mode and e ect analysis are carried out at component level for an electrical winch. Construction of a Simulink model, used to verify the algorithms, are described in detail including governing equations and implementation. The basis of a structural analysis is outlined and tested on the electrical winch system. Results from the simulation model covers faults in per…
Modelling, Simulation and Control of offshore crane Develop a kinematic and dynamic crane model and study of several control designs
2018
Master's thesis Mechatronics MAS500 - University of Agder 2018 This master thesis is about Modelling, Simulation and Control of a MacGregor Active Heave Compensation (AHC) 250t crane operating on the supply vessel Gran Canyon. The crane model was developed mathematically using robot modeling theory including both kinematic and dynamic equations. This model was developed and simulated in Matlab and Simulink and further compared, where the two models showed equal results. Control designs for an offshore crane can be developed in several ways, but in this thesis the control task only concerns position control of the crane and can be divided into two control tasks. The main goal is to determine…
Dual-speed planetary gearbox for internal mounting in winch drum : design, actuation, and control
2018
Master's thesis Mechatronics MAS500 - University of Agder 2018 Konfidensiell til / confidential until 01.07.2023
Silica Green Stone as an SCM in concrete paving stones production : In order to reduce the total environmental footprint
2021
Master's thesis in Civil and structural engineering (BYG508) The cement industry is responsible for around 7% of the global CO2 emissions. Reducing this number has been on the forefront of the industry's mind for decades, but even with constant improvement and constant reduction in CO2 emissions per tonne cement used, the increasing globalization has kept the emissions high. Research in the industry has discovered supplementary cementitious materials (SCMs), that when partly replacing cement will produce most of the same results. SCMs are by-products from other industries and natural progression has led to the need for new ones. This thesis is, together with UiA, Aaltvedt Betong, SINTEF and…
Post weld heat treatment of welded low alloyed steel pipes : Use of AISI 4130 steel in hydrogen sulfide environment and its post weld heat treatment …
2019
Master's Thesis Civil and Constructional Engineering BYG508 - University of Agder 2019 Based on the results from pre-projectand workcovered by this thesis, no better alternatives to AISI 4130 material was found, neither could it be safely concluded for removal of NACE MR0175/ISO 15156 requirementsin any parts of high-pressure drilling fluid system. SinceAISI 4130 hasshown to be the optimal choice for the system,it was decided to look forimprovementsof welding procedure by optimization ofpost weld heat treatmentforthis steel.Heat treatment is an expansive and time-consuming procedure that,if not done correctly,could weaken the materialand jeopardize the safetyof the system.Inthis thesis, whi…
Investigation of the effect of different post-weld heat treatment procedures on pipe strength and integrity : Calibration of numerical plasticity for…
2020
Master's thesis in Civil and structural engineering (BYG508)
Regional climate model simulations for Europe at 6 and 0.2 k BP: sensitivity to changes in anthropogenic deforestation
2014
International audience; This study aims to evaluate the direct effects of anthropogenic deforestation on simulated climate at two contrasting periods in the Holocene, ∼ 6 and ∼ 0.2 k BP in Eu-rope. We apply the Rossby Centre regional climate model RCA3, a regional climate model with 50 km spatial resolution, for both time periods, considering three alternative descriptions of the past vegetation: (i) potential natural vegetation (V) simulated by the dynamic vegetation model LPJ-GUESS, (ii) potential vegetation with anthro-pogenic land use (deforestation) from the HYDE3.1 (History Database of the Global Environment) scenario (V + H3.1), and (iii) potential vegetation with anthropogenic land …
Electronic structure of EuO spin filter tunnel contacts directly on silicon
2011
We present an electronic structure study of a magnetic oxide/ semiconductor model system, EuO on silicon, which is dedicated for efficient spin injection and spin detection in silicon-based spintronics devices. A combined electronic structure analysis of Eu core levels and valence bands using hard X-ray photoemission spectroscopy was performed to quantify the nearly ideal stoichiometry of EuO “spin filter” tunnel barriers directly on silicon, and the absence of silicon oxide at the EuO/Si interface. These results provide evidence for the successful integration of a magnetic oxide tunnel barrier with silicon, paving the way for the future integration of magnetic oxides into functional spintr…