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738 Uppsatser om Wave Spring - Sida 3 av 50

Konstruktion av Industriellt Vibrationsmätningssystem med signalbehandling baserad på Digitala Vågfilter av Lattice-struktur

In this bachelor thesis a complete prototype of an industrial vibration measurement platform has been developed. By measuring a number of variables such as acceleration, temperature and speed conclusions can be drawn on machinery health. The aim is to evaluate hardware and software solutions for a possible future product. Based on a requirement specification a proper hardware design has be developed. The hardware consists of a four-layer PCB with an ARM Cortex-M3 microcontroller and about 250 other components. The PCB was designed, assembled, tested and finally housed in a box.

MPD-vågformer för helikopterradar

A helicopter based system equipped with a millimetre-wave fire control radar is studied for improvement of the detection probability for moving ground targets. The system is a pulse doppler radar that sends out the electromagnetic wave in repetitive pulses. The frequency in which radar sends this pulse is called Pulse Repetition Frequency (PRF). The velocity of the moving targets is measured by spectral analysis of the pulses received. With this sort of system some targets will not be possible to detect.

Val av tidpunkt för markberedning vid naturlig föryngring under skärm av Pinus sylvestris i Svealand : Timing of scarification when using natural regeneration in seed tree stands of Pinus sylvestris in Central Sweden

This thesis is built on a field study that was carried out in two seed-tree stands near by Götbrunna in Uppland, Sweden. The aim was to examine if scarification carried out in spring time could generate a more dense seedling establishment when using natural generation, than scarification carried out in autumn. It was also investigated whether there were differences in mortality the first season between the two plot-types. Plots were established block-wise with 50 blocks (pairs) on each site. The spring scarification was made with a hoe during 22-23 of April.

Doing Business in China - A Best-practice Model for Foreign Invested Small and Medium-sized Enterprises (SMEs)

Foreign invested SMEs have recently become increasingly interested in China. The enterprises are in this report categorized as second wave companies since they follow the footsteps of previous pioneers, of which mostly were larger companies. The ambitions of the SMEs are either to sell products on the ever expanding Chinese market or to utilize the potential of low cost production for global markets. The existing literature is fragmented and solely based on the experience of larger companies. We believe that SMEs are facing new and different challenges, and thus a new generic theoretical frame work is desirable.

Fånggrödor i Norra Östersjöns vattendistrikt

70 % of the lakes and waters in the water district of northern Baltic Sea do not reach the requirements for good ecological status. This is mostly due to eutrophication caused by a too high deliverance of nutrients from agricultural land or effluents. Losses of particulate phosphorus through water erosion contribute to a great extent to this eutrophication. In the action plan for the water district cover crops are mentioned as a measure for reducing losses of phosphorus from arable land. This paper reviews the possible effect of cover crops in the water district and discusses what crop that would be most suitable.

Kustnära ekosystem som skydd mot naturkatastrofer : en litteraturstudie från ett riskhanteringsperspektiv

Research suggests that society's vulnerability to natural disasters along coasts could increase as a result of climate change, which is likely to lead to elevated sea levels and possibly an increase in the occurance of meteorological phenomena such as storms and tropical cyclones. Following the Indian Ocean tsunami disaster in 2004 and Hurricane Katrina in 2005, both of which received considerable media attention, empirical data has indicated that coastal vegetation might be able to protect and reduce damages to coastal communities during tsunami events and tropical cyclones.The aim of the essay has been to study the function of coastal ecosystems as protection against tsunami waves and storms from a risk management perspective, meaning that I have, through an overview of scientific articles, compiled current research on how coastal ecosystems can attenuate storm surges and tsunami waves, and analysed how this knowledge can be put into practice in coastal communities from a risk management perspective, i.e. if coastal ecosystems are a viable risk reduction measure, are practically applicable, and if so, how they could be applied.There is empirical evidence suggesting that coastal ecosystems, particularly mangroves, can reduce the strength of a tsunami wave, but full scientific consensus on this issue has not yet been reached. With regard to protection against storm surges, there is extensive scientific evidence that coastal vegetation can mitigate damages and reduce the height of a storm surge, although the wave has to traverse several kilometres inland through thick vegetation for the protection to be effective. A synthesis in the form of a figure regarding the many physical factors that influence wave development through coastal ecosystems has been created in an attempt to simplify and explain the phenomenon.The conservation and restoration of coastal ecosystems can be justified from a risk management perspective, but planting new forest belts for the purpose of disaster mitigation is quite unrealistic and can rarely be sustainable, since, for protection to be effective, the forest belt must extend several kilometres inland from the coast, and would thus likely prove difficult to implement along coastal societies..

Doing Business in China - A Best-practice Model for Foreign Invested Small and Medium-sized Enterprises (SMEs)

Foreign invested SMEs have recently become increasingly interested in China. The enterprises are in this report categorized as second wave companies since they follow the footsteps of previous pioneers, of which mostly were larger companies. The ambitions of the SMEs are either to sell products on the ever expanding Chinese market or to utilize the potential of low cost production for global markets. The existing literature is fragmented and solely based on the experience of larger companies. We believe that SMEs are facing new and different challenges, and thus a new generic theoretical frame work is desirable.

Vilken föryngringsmetod ger bäst resultat på torra och friska marker, höst- eller vårplanering? : en jämförande studie utförd på uppdrag av Stora Enso Skog

Regeneration with scarification and planting is a well known method, but the plants have a tuff period in the beginning. Decease of plants comes from pine weevils, dry weather, browsers, wrong method of scarification and wrong time for the planting. These are some courses why not every planting gets successful. The purpose with this study is to investigate witch time of planting gives the best result, spring or autumn planting and to give a answer of witch factors are the main course of deceases. The goal is to have the study to decide witch time to plant after final felling. The choices of plantings were maid from a period of three years. Spring plantings were from year 2005, 2006 and 2007 and autumn plantings were from 2004, 2005, and 2006.The purpose was to compare differences in deceases at the same spring weather.

Underkambriska böljeslagsmärkens bildningsmiljö : Ett försök att fastställa fossila ripplars avsättningsmiljö med hjälp av recenta sandbottnar

ABSTRACTThe fauna of the Lower Cambrian is far from fully understood, as is the environment of that epoch. Some of the most crucial moments in the history of evolution takes place during this epoch; the Cambrian explosion and the appearance of ecosystems as we know them. That makes it an important period to investigate. Doing so, the Lower Cambrian offers a lot of problems, one of which is that body fossils are seldom preserved. That has often left us with trace fossils to create an image of the Lower Cambrian life, but also some bedrock features such as ripple marks.The main purpose of this work has been to investigate the possibilities of relating the wave lengths and forms of recent wave-generated ripples to fossil ones, and also to evaluate the methods for that kind of comparison.

Brikettillverkning på gårdsnivå :

In my work I have chosen to examine the profitability for small scale production of hemp briquettes. My study also includes a review of which briquette technique that is the most common one among small scale producers. The reason that I have chosen this subject is because of the discussions about climate and energy that we face almost every day. I also think the subject is extra interesting in these days when the grain prizes are at a historic high level. In order for me to achieve a reliable report, a hemp and briquette producer has given me the actual data from his farm. In that way I have been able to make my calculations from a concrete perspective.

Effekter av predationsrisk på sånglärkors (Alauda arvensis) habitatval på åkermark

Along with other European farmland birds, the skylark (Alauda arvensis) has declined rapidly since the 1970?s. Between 1975 and 2003, the Swedish population of skylarks declined with 64 %. In Britain, the decline is often explained by alterations in farming practices in general and the shift from spring-sown to winter-sown cereals in particular. The dense vegetation structure of winter cereals is limiting the number of breeding attempts possible, causing the entire population to decline.

Reducerad jordbearbetning : en fallstudie

This is a study made because I would like to see how much money can be saved when reduced soil preparations is used. This is a case study, the farm is located in the north vest part of Skåne, Sweden. I have calculated with four different soilpreparation methods. Alternative 1: Conventional soil preparation, the way the farm is managed today. Alternative 2: Ploughing on depth of 12 centimeters, with a ridge packer followed with sowing. Alternative 3: Eco-tillage Alternative 4: Direct drilling The results of my study showes that Alternative 2 is the most profitable. Alternative 4 is very good if you see to dieselexpenses and hours of work, but the yield is far to low. If the numbers are further analized, it showes that in spring barley the differense between Alternative 2 and Alternative 4 is at a minimum. So if there is lack of time for one reason or another, this might be an alternative in spring barley. The differense in how the farm is managed today and the most profitable alternative in the study, Alternative 2 showes that it can be saved up to 60 940 SEK..

Geografisk prioritering av CTI-utrustad virkestransportkapacitet

Previous studies of central tire inflation (CTI) in truck transport of roundwood have shown potential benefits to include more even wood flow and reduced road damage. The greatest benefits are found to be during periods of low bearing capacity such as spring thaw. No previous studies have examined geographical variations in the potential benefit of CTI-equipped trucks. The aim of the study was to develop and use a simple method for geographically prioritizing the use of CTI-equipped trucks within a forest company´s sector of activity.The host company for the study was Holmen Skog. The area studied consisted of Holmen Skog?s entire sector of activity extending from the province of Västerbotten to the province of Småland.

Rekursiv greyboxidentifiering av drivsystem i industrirobot.

In modern industrial robots the components in the transmission contain nonlinearities. These nonlinearities need to be to estimated either for better control or to use the parameters for diagnosis of the system. There is a lot of work done within system identification and mainly within the field of iterative parameter estimation.This thesis considers recursive grey-box identification for a nonlinear model of the transmission in an industrial robot. The nonlinearities that are identified are friction, spring stiffnes, hysteresis and backlash. These nonlinearities are a part of the models that are presented in this thesis.

Kraftanalys och framtagning av mätanordning för vertikala vindkraftverket Lucias bärarmar

The project contains a force analysis of the vertical axis wind turbine Lucia's supporting arms and a measuring device to experimentally measure the forces is made. The forces between the supporting arms and the tower are calculated theoretically and then simulated by a computere. A measuring devise is then designed to measure the forces experimentally. The forces acting on the attachment between the supporting arms and the tower is primarily the centripetal force, gravitational force and the aerodynamic forces on the rotor wings. The maximum forces were theoretically calculated and is 13.38 kN along the x-axis, -0.25 kN along the y-axis and then 0.5 kN along the z-axis.

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