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4906 Uppsatser om High-frequency - Sida 12 av 328
Hållbar utveckling i Kungsängen : ett gestaltningsarbete med fokus på folkhälsa, biologisk mångfald och ekologisk dagvattenhantering
Tail-biting in pigs is an animal welfare issue and in Sweden during 2002 the producers lost tree million Swedish crowns because of tail biting. This economic loss depends on the pigs which are discarded at slaughter because of tail biting. Tail biting can be separated into two stages, "pre-injury" and "injury". The aim of this study is to investigate if tail biting depends on environment or genetic background.A lot of research on the environments effects on the behaviour of pigs but not so much on the genetic effects has been performed. The frequency of tail biting in pig farms influence among others of environment enrichment, ventilation, gender and breed of the pig.
Upplevelse av arbetsglädje och känsla av sammanhang - en enkätstudie bland anställda på en högskola
Man spends most part of the day at work and is therefore influenced by it?s ambience. That?s why it?s important that the environment at work is health promoting and can function as a supportive environment. The purpose of this study was to describe job satisfaction among employees and to analyse a possible connection between job satisfaction and employees experiences of SOC.
Vakuumbrytare i småskaliga vattenkraftstationer
This master thesis has been performed at Vattenfall Power Consultant in Gothenburg and Trollhättan for Vattenfall Vattenkraft. In this report vacuum circuit breaker in small-scale hydropower stations with the rated power 4 MVA and below has been studied. Models of the stations are modeled and analyzed in PSCAD/EMTDC to study the high voltage transients that are created after current chopping with vacuum circuit breaker. Vacuum circuit breaker may chop the current before it reaches zero value, which means that high voltage transients can be created. The equipment of the stations can be destroyed by high voltage transients.The purpose of this thesis is to examine the use of vacuum circuit breaker in small-scale hydropower stations and the risk for high voltage transients from current chopping.According to the results there is a risk of high voltage transients after current chopping with small synchronous generators in stations with the operating voltages 0.4 kV and 3.6 kV.
Social Demokrati : Sociala medier, Politiker och Demokrati
The aim was to explore how the first page of a student newspaper has been changed over time since it was founded in the 1960´s.This thesis explores how the front page of the student newspaper Lösnummer has been changed since it was founded in 1966. It concerns the location and frequency of elements and it is based on theories of layout, the first page and visual communicationIn addition, the thesis develops a new kind of method for determining the location of elements on the type area. The method is based on the hexadecimal number system. It is formed as a grid which is placed on the first page to determine the location of the elements.It concludes that the frequency of elements had its peak during the 1970´s and has ever since decreased gradually. Image placement has gone from being scattered all over the front page to be centered and increase in size. .
Motivation for eating roughage in sows : as an indiction of hunger
Today?s feeding methods can determine the domestic pig?s abilities to fulfill basic behavioral needs, such as foraging, and the way in which pigs are feed is an important aspect. Feed does not only provide the energy and nutrients critical for survival, but feeding is also associated with a number of other factors contributing to well-being and reproduction. Today the feed for gestated sows is often composed by high energy and low dietary fiber grain products such as wheat. Three kg of this kind of feed can often be consumed by the sow within 20 minutes.
A comparison of transporters? paddle use when unloading pigs at slaughter
Today, pigs are moved on farm, between farms, between countries and to abattoirs. This movement of live pigs requires handling practices that are designed for the purpose. The objective of this study was to research the use of paddle in moving pigs, to investigate if there were different methods of paddle practice, explore the time efficiency of different kinds of paddle use and if there were any time variations in methods that varied in intensity of touch. This study was done on two Swedish abattoirs for a total of five weeks. A total of 22 transporters working at two different abattoirs where studied during unloading of pigs at the abattoirs.
What can change the nature of a grade? : A study of computer games and how they affect English grades.
The purpose of this study is to establish whether or not there is a connection between a highincidence of computer gaming and English proficiency in Swedish 9th-graders. The study also takescomputer game genres into account, attempting to see if there is a link between frequent playing ofcertain genres and high English grades.According to this study, there is a clear correlation between the gaming habits of Swedish 9thgradersand the grades they receive in English, with a higher frequency of gaming corresponding toa higher grade. The study also suggests that the Strategy, MMO (Massively Multiplayer Online) andCRPG (Computer Role-Playing Game) genres have a higher representation amongst students withgood grades in English..
Gränsöverskridande handel ur importörens perspektiv
Research in international trade situations has mainly focused on understanding the exporter?s actions and has showed ways on how these can be optimized. Although the importer in most cases, until this day, has been left outside this focus, it has been showed that the importer often is the active participant in an international dyad. It is the importer who is actively seeking suppliers for its production or distribution. Based on previous research in the area, the following study identifies the factors that are vital to the importer for satisfactory relations.
Drivförstärkare : Bredbandig drivförstärkare med hög verkningsgrad
This report present the design and manufacturing of a wide-band driver amplifier placed in radar module for airborne applications. The major goals for the amplifier were a high efficiency and to deliver a predefined output power. To reach the second goal an additional preamplifier had to be constructed. The amplifiers were constructed in three steps: Design and Layout in the software Microwave Office, Mounting components and Verification. The driver amplifier was decided to be a push pull configuration consisting of two parallel transistors biased in class AB.
Upplevelse av arbetsglädje och känsla av sammanhang - en enkätstudie bland anställda på en högskola
Man spends most part of the day at work and is therefore influenced by it?s ambience. That?s why it?s important that the environment at work is health promoting and can function as a supportive environment. The purpose of this study was to describe job satisfaction among employees and to analyse a possible connection between job satisfaction and employees experiences of SOC.
Relationen mellan cyklister och fotgängare vid Södra Älvstranden, Göteborg En utvärdering av trafiken på cykelstråket Älvsborgsbron - Centrum
This paper describes a method for wireless energy transfer via near-field electromagnetic inductionthat is inexpensive, simple and can be applied to almost any type of system, regardless of size andenergy demands.The method uses a primary unit consisting of an oscillator, amplifier and inductive coil thattransfers energy to a secondary unit consisting of a coil, rectifier and voltage regulator. Two typesof oscillators and several amplifier designs were realized and evaluated together with a multitudeof flat coils of both monofilar and bifilar type.The results show that it is important to use an oscillator whose frequency is dependent on theinductance of the connected transmission coil, such as the Colpitts oscillator. This is preferable toan oscillator with a preset frequency, such as a Schmitt-trigger oscillator..
Produktivitet vid selektiv mekaniserad bioenergiröjning av eftersatta röjningsbestånd :
In Sweden, harvesting pre-commercial thinning (PCT) stems for energy purposes is a interesting way of financing the high cost of preparing dense stands for a profitable first conventional thinning. This concept can be labelled bioenergy thinning.
The aim of this study was to quantify the productivity of a Vimek 404R light harvester with an accumulating Naarva-Grip cutting head during the bioenergy thinning of a self-regenerated stand west of Sunnansjö in Dalarna. The stand was birch-dominated, contained 15 371 stems/ha, and measured on average 4,6 cm Dbh and 7 m tall. Even though the driver was well experienced with the machine, the stand in question was the first one that he ever thinned in this manner. Nevertheless, the driver strived to accumulate as many stems as possible during each crane cycle and chose to cut taller stems in half so as to make the handling and forwarding of the harvested stems easier.
Barn och buller : Hur barn och verksamhet på förskolan påverkas av en hög ljudnivå
There are a lot of different sounds in our sound saturated time. Noise is an unwishable soundand a high sound level can give short- or lingering problems for both children and adults.The purpose was to find out if and in that case why children and the activity at the pre-schoolaffects by a high soundlevel. Another purpose was to examine what the effects would be if thepedagogues set about the work to get a good sound environment at pre-school.The investigation was accomplished in shape of qualitative interwievs where six pedagoguesfrom different pre-schools answered questions about a high soundlevel.All of them have been educated to hearing pilotes.The result of this investigation shows that some pre-schools have a high sound levels but notall of them. In those cases where there is a high soundlevel are there often too many childrenat the same place on the same time. That makes the soundlevel even higher and both childrenand adults are getting tired.By improving the sound environment at the pre-school both children and adults often gets abetter activity.Keywords: high soundlevel, hearingpilot, noise, affects on children..
Järnberikning av mjöl : exemplifierat med Egypten och Iran
The purpose of this study is to give an overview about iron fortification from the view of technique and health. Example of a technical aspect is different iron compounds which are used for fortification like ferrous sulfate, ferrous fumarate and elemental iron. In the aspect of health the big question is if iron fortification can improve the health in reducing the prevalence of anemia. The study focuses on flour fortification with iron in Egypt and Iran and involves a literature study with scientific articles. Also information from WHO (World Health Organization), FAO (Food and Agriculture Organization) and FFI (Flour Fortification Initiative) are used.Fortification means an intentionally increasing of the content of micronutrient in foods with the aim to improve the food quality and deliver a nutritional benefit to the consumer.
Vad styr förekomsten av sälg och asp? : en studie av olika beståndstyper inom Hamra kronopark, Dalarna
Aspen (Populus tremula L.) and goat willow (Salix caprea L.) are two important tree species in the aspect of nature conservation. Due to the elimination of forest fires, a former negative attitude towards deciduous trees in forestry and a strong herbivore pressure, these tree species have been negatively affected during the last fifty years. The aim of this study was to investigate whether the occurrence of aspen and goat willow could be related to either human impact or to site properties, such as ground moisture and vegetation type. A side study included an inventory of a number of cyanobacterial tree lichens on aspen and goat willow in order to try to relate the occurrence of these lichens species to stand history and stand properties.
The study was performed in Hamra State Forest in northern Dalarna. Nature reserves were compared with stands in managed areas.