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445 Uppsatser om Load dump - Sida 7 av 30
Momentbärförmåga för semikompakta ståltvärsnitt av HSQ-balkar : En modell för interpolering mellan eurokodens klass 2 och 3
The current standards for design of steel beams are divided into four classes based on the slenderness of cross-sectional parts. Depending on the section class a beams load capacity is either determined by a plastic, elastic or a reduced elastic model. The division between cross-sections calculated by a plastic and an elastic model is today done in a very harsh way with no smooth transition. This leads to a large difference in the calculated resistance for the sections located near the class limits. Elasto-plastic sections are in the current situation calculated as purely elastic and their large plastic reserve is not considered in the current standards.
Utredning av frekvensregleringens påverkan på mekanisk utrustning i en kaplanturbin
As a consequence of increasing wind power installations in the Nordic grid the last years, the need for regulating power has become larger. In the Nordic grid, regulating power is mainly provided by hydro power. One part of the regulating power is called frequency control, which ensures that the grid frequency is stable and close to 50 Hz.However, setting the turbine into frequency controlled operation may cause stress and wear of the components in the mechanical control system. Frequency controlling implies large and frequent servo forces and longer travelling distance of the sliding bearings in the Kaplan turbine.Based on one selected Kaplan turbine, Selsfors G1, measurements and MATLAB calculations have been performed in order to determine forces and movements of the linkage system. With these forces and movements as input, stresses and fatigue have been determined as well as sliding distances, bearing pressures and wear of bearings during a typical lifetime of 40 years.The results indicate that no severe wear exists on the bearings during 40 years of service.
Det allmännas skadeståndsansvar : Skadeståndsansvar för ideell skada enligt frihetsberövandelagen
BACKGROUND: Today?s societal changes, including high rate of change and increasing information flows, are increasing the demand on the individual mental capacity. It becomes increasingly difficult to analytically process all the different dilemmas and everyday decisions as individuals have a limited mental capacity available to make these decisions. Thus, it has been suggested that ego-depleted relies more heavily on intuition, which is less burdensome, when making decision. However little is known about to what extent intuitive decisions differ from analytic.
Dimensionering av betongkonstruktioner : En jämförande studie av BBK 04 och Eurokod 2 vid dimensionering av balkar och pelare
Today, we use BKR and BBK 04 when designing concrete structures inSweden, which will, in the near future, be replaced by Eurocode 2. When you are designing buildings, you will use Eurocode 2 Part 1-1 and with this new standard, some new rules and general rules will be necessary to adopt. To examine how BKR and BBK 04 tells apart from Eurocode 2 when designing concrete structures, one beam and one column with often common dimensions, is studied. The beam is designed with consideration of (considerate to) durability at bending moments, shear forces and control of cracking. The column is designed with consideration of durability at eccentric axial load and bending moments in cross section on account of (due to) geometric imperfections. BBK 04 has gone one step closer to Eurocode 2 than earlier editions and the things that are different, when calculating reinforcement, is how they use the partial factors.
Jämförelsestudie för tre olika metoder att beräkna genomstansning i betong : Skillnader i genomstansningskapacitet för metoderna i BBK04, EK2 och BHB
Before the European construction standards were introduced in January 2011, it was mainly themethod in BBK04 that was used for calculating punching capacity in concrete structures, and in lesscommon cases the method in BHB. The method of BBK04 is easy to use and have had the samestructure since the first was published in 1979. The Concrete handbook method (BHB) where usuallyonly used when a higher punching capacity was needed and the cross-sectional height where fixed,calculations using this method entails more work, but will in return usually give a higher capacity. Italso allows the use of shear reinforcement to increase the cross-section capacity. The method ofcalculating punching shear in EC2 differs largely from the methods of BBK04 and BHB.
Frekvensreglering i det nordiska kraftsystemet
Svenska Kraftnät is (together with the other transmission system operators of the Nordic power system) responsible for keeping balance between the generated and demanded power in the Nordic power system. Spontaneous load variations and system disturbances, however, lead to power imbalance followed by frequency variations. The frequency deviations can be limited to an acceptable level by the spinning reserve, mainly by hydro power control. But there are also other system properties which have a great influence on the frequency and system stability. The frequency and voltage dependence of the loads have a direct influence on the power balance.
Utvärdering av den bärande tegel- och betongstommen i en byggnad från år 1916
This Master thesis is about a postal- and telegraphic building in Eskilstuna, Sweden. The construction methods for the specific building and buildings in general from the same time are described. The purpose of the report is to describe the loads acting on the building and how it has been built and why it has been rebuilt during the years. After this, possibilities of reconstruction and adaptation for today?s demands can be evaluated.
Skotares bränsleförbrukning :
In published studies it is found that the fuel consumption on a forwarder is relatively constant, on time basis. A certain variation between different sizes of forwarders occurs as well as between different working elements.
The aim of the study was to establish a forwarders comparatively fuel consumption when driving on road and in the terrain, loaded and unloaded, with high and low gear and with high and low speed as well as with hydrostatic and hydrodynamic transmission. A hypothesis was that low rpm gives lower fuel consumption on distance basic, at all trials.
The test driving was made with a Hemek 750 which is a three geared hydrostatic machine and with a Hemek 700 which is a hydrodynamic machine with six gears.
Undersökning av elkvalitet i distributionsnät med omfattande vindkraftselproduktion
The goal for this master thesis project has been to investigate the power quality in adistribution grid, which has a high fraction of dispersed power production due towindmills. The study has been done on a grid in Laholm South of Halmstad, whereapproximately 45 windmills are connected to the distribution grid owned by SHKEnergi. The investigation has been focused on to two radialy fed 20 kV lines, wheretwelve windmills are connected.Voltage variations have been studied by creating a model of the grid in the simulationprogram SIMPOW. The largest deviation that has been found in any point of the gridis ±1.9 % of the nominal voltage. This deviation is a result of varying powergeneration from the windmills and the voltage regulation at the connection point ofthe line.
Kinematisk och dynamisk modellering av den haptiska enheten TAU i sex frihetsgrader
The thesis presents an optimally designed kinematic structure for a new 6-DOF haptic devicebased on TAU configuration. The configuration of the TAU-2 proposed by Suleman Khan andKjell Andersson [1] was modified and its mobility was verified by using Grübler criterion tohave a 6 DOF. Analytical kinematic models for the inverse and forward kinematics weredeveloped for the haptic TAU configuration to determine a set of optimal design parameters.Kinematic performance indices such as volume of the workspace, kinematic isotropy and payload index, were defined based on the singular values of the Jacobian matrix. The Jacobianmatrix was scaled to homogenize the physical units. The Jacobian matrix dependent on theposition and orientation of the end-effector gives local isotropy and pay load index, so globaldesign indices were defined, which represent the performance of the mechanism in the wholeworkspace.
End of line test : En studie av företaget Emotrons linjetestning i produktionen
Emotron is a company specialised in developing, producing and marketing equipment to con-trol, monitor and protect processes and machinery driven by electric motors, with an applica-tion focus. Examples of uses for their products are fans, pumps, lifts and cranes.The project is to look at Emotrons end of line test. The company has seen that at the final test-ing there is a bottleneck that restricts the outflow and prevents an increase in the number of tested products.The purpose of this project is to review how Emotrons end-of-line test works today and if there is a possibility to make the test more efficient in such a way that the quality is not at risk, while increasing the outflow of tested products.The projects first step is to look at and analyse what is causing the bottleneck at the end-of-line. When the analysis is complete, the next step is to review whether there is a possibility to solve the bottleneck and if so in what way can this be done. Emotrons most overall objective of the project is to increase the outflow of the number of tested products without jeopardizing the quality.An analysis has been made on frequency inverters, soft starters and shaft power monitors.
How Does Ego Depletion Affect Moral Judgments and Pro-social Decisions?
BACKGROUND: Today?s societal changes, including high rate of change and increasing information flows, are increasing the demand on the individual mental capacity. It becomes increasingly difficult to analytically process all the different dilemmas and everyday decisions as individuals have a limited mental capacity available to make these decisions. Thus, it has been suggested that ego-depleted relies more heavily on intuition, which is less burdensome, when making decision. However little is known about to what extent intuitive decisions differ from analytic.
En studie av retentionen i floden Oder och dess avrinningsområden, Polen.
Nutrient enrichment is the main cause of the increasing eutrophication process in the Baltic Sea during last century. A prerequisite counteract this process the load of nutrients to the Sea must be investigated. The large contribution of nutrients to the Sea is caused by emission from the rivers within the drainage basin. For the total emission of nutrient into the Sea the retention process in the rivers has big influence. This process in the river system has been assumed as a not important part of the nutrient cycle.
Värmning av avloppsvatten med spillvärme för att förbättra kvävereningen -Temperaturens inverkan på kvävereningen
The goal for this master thesis project has been to investigate the power quality in adistribution grid, which has a high fraction of dispersed power production due towindmills. The study has been done on a grid in Laholm South of Halmstad, whereapproximately 45 windmills are connected to the distribution grid owned by SHKEnergi. The investigation has been focused on to two radialy fed 20 kV lines, wheretwelve windmills are connected.Voltage variations have been studied by creating a model of the grid in the simulationprogram SIMPOW. The largest deviation that has been found in any point of the gridis ±1.9 % of the nominal voltage. This deviation is a result of varying powergeneration from the windmills and the voltage regulation at the connection point ofthe line.
Konstruktion av infästning till dysa
The goal of this thesis is to design an attachment between a duct and a pod. A pod is what could be compared to an outboard engine for larger vessels. The pod is placed on the outside of the ship?s hull and can rotate 360 ?. A duct is a large steel ring that can be placed around the propeller on the pod to increasethe propulsion force of the ship in lower velocities.