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695 Uppsatser om Frequency - Sida 14 av 47

Trafikverkets effektstyrningssystem - EFS 132 kV : Bidraget till minskade förluster

The technological legacy from the early electrification of the Swedish railroads has resulted in a power grid with a lower grid Frequency than the national power grid from which it is fed. Energy transfer between these power grids with different frequencies requires substations, adapting the grid Frequency for the rail road power grid. For this purpose, a feeding power grid has been built, stretching across the country from Boden in the north to Tälle/Häggvik in the south.Power transfer in the Swedish power grid results in voltage angle differences which increase with increasing loads and transfer distance. These voltage angle differences are transferred from the power feeding substations to the rail road power grid, will in some extent cause loss of energy due to unwanted power flows from north to south.To minimize the losses due to this phenomenon, a power management system called EFS 132 kV has been developed and implemented. The system minimizes the unwanted power flows and controls the desired power flow for a good distribution of loads between the power feeding substations.This thesis investigates the extent of the transmission losses avoided due to the EFS 132 kV that coordinates the idling angles to a common reference point.The results indicate that EFS 132 kV affects the power flow, especially between the northern substations through an improved load distribution.

Orsaker till kalvningssvårigheter och dödfödslar hos SLB och SRB

Difficult calvings and stillborn calves are costly for the producer and lowering these frequencies can decrease the costs for the dairy operation. Each calving in the herd is registered by the farmer and stored in a central database. The information is used to monitor the level of calving-difficulties and stillborn calves in the herd and nationally. Monitoring of these registrations is important to detect possible changes. Breeding-value prediction for calving traits is based on the calving information in the database.

Analys av PWM-mönster i Matlab

One of ABB Power Systems´s business areas is HVDC (High Voltage Direct Current) technology. HVDC is used for transmissions for both short and long distances. One of Power Systems?s products is called HVDC Light. HVDC Light is a relatively new technology for power transmission, but have before only been used for motor drives applications.

Analys av Husqvarna AB:s lastbilstransporter till Italien

The thesis has been written as a part of the Bachelor degree in Industrial engineering and management at the School of Engineering in Jönköping. The work is focused on the part of Husqvarna AB?s supply chain that is associated with the lorry transports to Italy. Husqvarna AB has approximately ten Italian customers, whose delivery patterns have been studied from January 2007 to July 2008. Some of the customers have a low delivery Frequency and small amounts of goods that they therefore have not been fully analyzed in this report.

Reducering av effektförbrukning i inbyggda system med Linux

Linux is a growing operating system in embedded systems. Today, Linux is not only in heavy servers but also in cell phones, PDAs, cameras and other devices running on battery power. While current technology is more energy efficient, more and more technologies are implemented into a single unit resulting in an overall increase of power consumption.Low power consumption is an increasingly important feature of a system today. Lower power consumption means lower costs, less environmental impact, and longer life for applications that runs on batteries.This work compiles methods to reduce power consumption of Linux systems. The work includes examining whether the available opportunities are platform-specific or of a more general nature.

Effect of low light intensities on dairy cows? behavior

The animal welfare act in Sweden states that dairy cows need to have at least a dim light present at night, but there are no recommendations for what intensity the light should have. It is unknown how cows perceive and react to low light intensities and earlier studies on this topic are limited. Red light as night light has also been suggested, based on the cows? inability to perceive red light. This have however been questioned. The aim with this study was to investigate how four different light intensities affect dairy cows behavior.

The effect of rapeseed oil and palm oil supplement and milking frequency on milk yield and milk fat quality

Milk fat is an important feature in many different milk products and other foodstuffs and it is often crucial for the dairy plants that the milk fat is stable for different manufacturing processes. Lipolysis is the enzymatic degradation of fat and is the one of the causes for an elevated amount of free fatty acids (FFA) in milk. Further, the change in fatty acid (FA) composition in milk can affect the stability of the product and also the manufacturing process. Both internal and external factors, at farm level or at the dairy plants can affect both FA composition and content of FFA. Milking Frequency (MF=number of milkings per cow and day) and the composition of feed are two examples of factors generally performed at farm level. The objective of the present study was to evaluate how FA composition of milk and amount of FFA are influenced by two different ingredients supplemented to concentrate.

Statistisk kartläggning av dimma längs E4:an mellan Helsingborg och Jönköping

Fog is a small-scale weather phenomenon that are fascinating to people. However, the presence of fog in road traffic reduces the visibility and increases the risk of road accidents. By the Swedish Road Weather Information System (VViS), the safety on roads could ameliorate and road accidents caused by fog and other weather hazards could be prevented. Fog is however a complex and usually local phenomenon, why fog formation generally is not easy to predict. For that reason, a statistical mapping of fog, especially along a motorway with high traffic volumes, could be useful in planning to prevent road accidents.

Kraftig anemi hos tax :

The Clinical Pathology Laboratory at SLU in Uppsala has analysed several blood samples from Dachshunds with severe anemia. As there are no previous studies on this topic, a study was performed to evaluate if Dachshunds are more prone to severe anemia compared with other breeds. In addition, a retrospective case study on Dachshunds with severe anemia was done to search for common risk factors or diseases. Hemoglobin values in samples from 1272 Dachshunds and 2269 German Shepherds analyzed from September 1994 to October 2007 were used to compare the Frequency of severe anemia in Dachshund and German shepherd. The samples were identified by laboratory information system.

Det gör ont när stockar spricker!

The aim of this study was to provide SCA Forest Norrbotten District with material to assist in their work towards decreasing the Frequency of bucking splits in their saw timber logs. SCA Forest supplies the Munksund sawmill with pine timber. Periodically the sawmill experiences problems related to bucking splits in their logs. The purpose of this study was to find an available method to measure the occurrence of splits directly on incoming timber. The ambition was also to gain some knowledge about possible variations between different logging crews in terms of split Frequency. If possible, this information could be used to investigate if certain crews produced more splits than others, and thereby making it possible to provide feedback to the logging machine operators. The study consisted of two major parts, a literature review, and a practical sawmill study.

Mätningar av statiska och dynamiska egenskaper för bakaxel.

To design new and high tech products the engineers rely more and more on computer based simulations to investigate the properties and behavior for a component or system.To verify these computer based simulations the dynamic properties for the components of the drivetrain needs to be verified. Therefore measurements of the stiffness and vibrations for the rear axle has been performed. This report show how the measurements has been implemented and evaluated, along with some interesting results for the rear axles properties.The static stiffness for the drive shaft along with the axle-gear has been determined. It is found that the stiffness for the whole rear axle is near the stiffness for the drive shaft, which means that the drive shaft becomes the dominant component of the system and affects the rear axle stiffness the most. The measured stiffness of the driveshaft is close to its theoretical stiffness.The stiffness for solely the hypoid-gear have been calculated using the stiffness for the rear axle and driveshaft, and thus has a range for the stiffness of the hypoid gear been determined.The backlash for the whole rear axle and for some individual components has been determined, where the backlash between pinion and crown-wheel has negligible impact on the total backlash.Measurements of the crown-wheel and pinion movements have been conducted, where the direction of movement is consistent with the theoretical direction of the forces.The vibration measurements show that the vibrations are more severe at certain rotational speeds.

Informationsutbyte och anpassning i affärsrelationen mellan elbolag och kunder

To identify the exchange and adaptation that takes place in the business relationship between electricity suppliers and electricity customers and analyze how these factors affect the strength of the relationship.The investigated concepts create synergies. The strength of the business relationship in the current situation is dominated by weak reciprocity in adaptation and an inefficient exchange of information with low Frequency..

Studie av en medeltida husgrund : en analys av bronsfynd från husgrund 6, Västergarn, Gotland

This essay is an analysis of the objects made of bronze found in an excavation Västergarn parish, Gotland, in 2010, conducted by the University of Gotland. The studied material presented in this essay comes from contexts inside, as well as nearby the foundation of a medieval building which purpose is still not certain. The first purpose of this study is to present the bronze-objects found inside and nearby the foundation of house 6, and to see if there are any datable objects. There is also a discussion whether there has been any bronze-crafting in the area. The second purpose is to make a contextual analysis to see if there are any differences between the material found outside and inside of the building, and what conclusions can be made regarding the function and use of the building.

Evaluation of Xilinx System Generator

This Master?s Thesis is an evaluation of the software Xilinx System Generator (XSG) and blockset for Matlab. XSG is a module to simulink developed by Xilinx in order to generate VHDL code directly from functions implemented in Matlab. The evaluation was made at Saab Avionics AB in Järfälla, north of Stockholm. In order to investigate the performance of this new module XSG to simulink, a model of a Frequency estimator often used in digital radar receivers were implemented in Matlab using XSG.

Vibrationsträning vid knäledsartros

In cooperation with Hälsoteamet Halmstad a pilot study was made to see if whole body vibration exercise has any effect on muscle strength, movement and experience of pain in people with knee osteoarthritis. Today whole body vibration exercise is a revolutionary exercise method that needs more studies to show the positive and negative effects. Osteoarthritis is a degenerative disease where more cartilage is destroyed than replaced. The most common symptoms are pain, stiffness, restricted movement, muscularly atrophy, tenderness and instability. The cartilage needs pressure to rebuild, it is therefore important that the patient exercise.

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