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729 Uppsatser om Erosion of rock mass - Sida 1 av 49
Bergerosion i utskovskanaler
Today?s climate changes will probably give rise to precipitation in Sweden, which will cause more floods in Swedish rivers. Many of the Swedish rivers are regulated and have lots of hydro-electro power plants. Higher floods in the rivers will give greater water loads on the dams, which mean that a higher discharge through the sluice gates and in the spillway channels is needed. High discharge of water in a spillway channel can create scour of the material in the channel.
Erosionsskydd i strandzoner :
Erosion in coastal areas is a common problem all around the world. The range of the problem depends on several factors, i.e. type of bed-rock and soil, wind and wave climate. Another factor is whether the area is of high interest, i.e. if the area is important for tourism and recreation, if there are houses and other buildings close to the shoreline or if it is a site of special scientific interest.
Vegetationens roll i erosiva vattendrag : en review och fältstudie av två nyckelområden i Rönne å
The vegetation?s impact on erosion control is widely explored, even though research? results are scattered where it suggests a both positive and negative relationship between roots and erosion tendency. Research has measured the roots? impact on erosion by many different methods, hence the aim of this study is to offer a clearance of what factors play an important role in the choice of appropriate species controlling river bank erosion. I have therefore
studied 17 articles concerning vegetation and erosion control, which were found in different databases such as: Web of Knowledge, Biological Sciences, Academic Search Elite and Google Scholar.
Ungdomars kunskaper om dental erosion och deras konsumtionsvanor av sura drycker- en enkätstudie i åk 2 vid en gymnasieskolaAdolescents? knowledge of dental erosion and their consumption habits of soft drinks -a questionnaire study among secondary school
The aim of this study was to investigate the knowledge of dental erosion and the consumption habits of soft drinks among secondary school students. Differences between the sexes should also be investigated. The study consisted of 102 students, 60 women and 42 men, in the eleventh grade from a school in the south of Sweden. A questionnaire with 25 questions, divided in two parts with focus on knowledge respective consumption pattern and behaviour, was handed out and collected by the authors. The data showed that more than 50% of the participants had knowledge about dental erosion.
Organisation av pop- och rockmusiksamlingar i Sverige: en värderingsfråga?
The purpose of this paper is to examine different methods for organisation and retrieval of pop and rock music recordings, and the problems concerned with this organisation. The focus is the question whether values towards pop and rock music influence the organisation of music in major Swedish record collections. As a background for this discussion, the study also discusses how music is organised in these collections, and what kind of problems are associated with their organisation. Also included in the paper is a minor investigation of how problems with the organisation of pop and rock music are dealt with in library and information science, and how values towards pop and rock music are dealt with in society in general. The main focus of the study, however, is an empirical study of how values towards pop and rock music manifest themselves in the pop and rock organisation of six Swedish institutions with major collections of music recordings.
Vegetationslösningar och andra metoder mot stranderosion :
Today 70 percent of the world's sand beaches are under recession due to erosion. The global warming may have the effect upon the sea level increasing and the erosion increasing on the sand beaches. To save these sand beaches, the erosion must be prevented. Coast erosion shelters like gabions and sea walls are functioning extremely well to protect the land behind the sand beach, but due to the wave reflections, created in front of these so called hard erosion shelters, the erosion of the front beach is accelerated. During the last decades, artificial sand supply (beach nourishment) has been the adopted praxis.
Skattning av fordonsmassa med driftstatistik
In the automatic manual transmission system, Opticruise, the choice of gear is based on several parameters such as road incline, driving resistance and vehicle mass. Many different mass estimations are made during driving. A final vehicle mass is then used to determine the current gear. Construction vehicles are often not equipped with air suspension and can therefore not estimate the vehicle mass when standing still. If that sort of vehicle is reloaded while standing still an incorrect mass estimation will be used and as an effect of that also a wrong gear.
Registreringsmetoder för initial och avancerad dental erosion : Litteraturstudie
Introduktion: Dental erosion definieras som förlust av tandens hårdvävnad genom en kemisk process som inte involverar bakterier. Dagens förändrade livsstil och kosthållning medför att våra tänder oftare utsätts för kemisk påverkan som kan leda till erosion. Det är flera faktorer som samverkar och dental erosion har en multifaktoriell etiologi.Syfte: Syftet är att beskriva olika registreringsmetoder för dental erosion.Frågeställningar: Vilka metoder kan användas för registrering av initial erosion? Vilka metoder kan användas för registrering av avancerad erosionsskada? Vilka metoder är kliniskt beprövade på patient?Metod: LitteraturstudieResultat: Ett flertal registreringsmetoder fanns beskrivna i litteraturen, merparten var inte applicerbara kliniskt. Registeringsmetoderna som framgick i den beskrivande litteraturstudien var: 3D scanning microscope (IFM), Atomic absorption spectroscopy (AAS), Digital photography (DP), Focus-variation 3D microscopy (FVM), Longitudinal microradiography (LMR), Non-contact confocal laser scanning microscopy (CLSM), Optical assessment, Optical profilometry (OP), Quantitative light-induced fluorescence (QLF), Scanning electron microscopy (SEM), Stylus profilometry (SP), Ultrasound, White light interferometry (WLI) och X-ray diffraction (XRD).Konklusion: Vid registrering av initial erosion krävs analys av tandytans mineralinnehåll samt optiska analyser med hjälp av instrument.
Hawkingmassa i Kerr-rumtid
In this thesis we calculate the Hawking mass numerically for surfaces in Kerr spacetime. The Hawking mass is a useful tool for proving the Penrose inequality and the result does not contradict the inequality. It also does not contradict the assumption that the Hawking mass should be monotonic for surfaces in Kerr spacetime. The Hawking mass is quasi-local and defined by the spin coefficents of Newman and Penrose, so first we give a discussion about quasi-local quantities and then a short description of the Newman-Penrose formalism..
Modellering av rotationssystem
This master thesis was conducted during the spring of 2014 at Atlas Copco Rock Drills AB in Örebro. The purpose of the thesis was to develop a simulation model of the rotation system for a hydraulic rock drill. In the future, the model will be used to investigate the phenomena called ?jerky rotation?. In order to validate the simulation model a test bench was designed and tests were made.
Förutsättningar och hinder för att använda offentlig upphandling som styrmedel för en hållbar hantering av entreprenadberg
Large volumes of excavated soil and rock are generated in building- and construction projects. These materials need to be transported longer and longer distances due to the densifications of cities. The transportation affects the environment in terms of noise and emissions, but also makes high demands on road infrastructure. To reduce the transport distances an increased responsibility for the excavated rock generated needs to be taken. Responsibility can be increased through an introduction of means of control.
Gröna tak i urbana områden
Bergkaraktäriseringssystem såsom RMR och Q (Rock mass rating och Rock tunneling quality index) används ofta i förstadiet av ett byggprojekt för att ge en tidig uppfattning om bergmassans karaktär och kvalitet. Informationen underlättar planeringen och det fortsatta arbetet genom att påvisa korrekta arbetsmetoder och risker. De två vanligaste systemen för att karaktärisera berg är RMR och Q, vilka båda med hjälp av fältbedömningar och beräkning betygsätter den aktuella bergmassan. RMR och Q har här använts för att karaktärisera en bergmassa i Huddinge kommun inför en planerad byggnation. Resultaten av karaktäriseringen med de båda systemen skiljer sig åt på vissa platser vilket sannolikt kan förklaras med systemens olika tillvägagångssätt.
Simulering av hydrauliska dämpare i borrslagverk
This master thesis consists of the creation of shock absorber models for percussive rock drills. A model of the rock was also developed. These models were connected to existing models of the rock drill to create a complete simulation of the rock drilling process.When the models had been created the rock model was evaluated by comparison with measured values from lab tests. The verified rock model was then used to evaluate the shock absorber models.Four new shock absorber concepts have been developed. Three of these have been modelled, while the fourth have only been sketched and described.The evaluation of the models showed the following:? Simulations of the single shock absorber don?t correlate to reality very well.
Rocksång - Fem sångpedagogers erfarenheter av den kvinnliga rösten
Rock singing - five vocal teachers´ experience of the female voice.The purpose of this study is to find out what different vocal teachers have to say about rock singing and the female singing voice. The method I have used to gather information is a phenomenographically inspired qualitative interview. The study begins with a few thoughts about my interest in rock singing, followed by a short overview about other research and literature that has been published on the subject. I have interviewed five vocal teachers in this study. All of them with many years experience of singing, both singing themselves and teaching professionally.
Erosionsproblematik vid dagvattenhantering : vegetationens betydelse
Erosion är en ständigt pågående naturlig process som kan bli ett problem när hastigheten överstiger vad som är hållbart för naturmarken eller den urbana miljön. Denna uppsats första del behandlar erosion som naturfenomen och produkt orsakad av människan. Erosionshastigheten och omfattning-en påverkas av jordens egenskaper, graden av täckande vegetation och markens lutning samt de naturkrafter som eroderar jorden. Tyngdpunkten i arbetet ligger på erosion i vattendrag. Texten skildrar vidare ingenjörsbiologi som lösningsmetod vid släntstabilisering.