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897 Uppsatser om Mechanical properties - Sida 47 av 60

Ljusets betydelse för rotknoppars groningsvillighet i åkermolke (Sonchus arvensis L.)

This study is about how changed light conditions induce dormancy in plants. It is divided in two parts. First a literature study where quantification of light, the concept dormancy, photoperiod and light quality are discussed. Second an experimental part, where the importance of light for sprouting capacity in root buds of perennial sow thistle (Sonchus arvensis L.) is investigated.In the science in how flowering in plants are induced the concepts short day/long day plants and light dominant/dark dominant are well-established. These concepts can also be applied to how light induce dormancy in plants.

Analys av lageregenskaper utifrån mätningar i testrigg

Vertical hydropower units has a rotating mass of up to 1000 tons. For the generator and turbine to work well the rotating system is required to be centered in relation to the surrounding structure. This is achieved by means of radial bearings. The dynamic characteristics of these bearings have a strong impact on the overall rotational dynamics of the total system and thus influence the vibrations in the unit. At Vattenfall Research & Development in Älvkarleby ongoing research is taking place on how the bearing parameters should be represented in the rotor dynamic calculations.

En ?terinventering och analys av den svenska populationen av svart nervmossa (Campylopus atrovirens)

Bristly swan-neck moss (Campylopus atrovirens) is in Sweden a very rare moss that only grows on a few blocks and cliffs around Gothenburg. The species can globally only be found in areas with high precipitation. Rain fall in Gothenburg has increased with a stronger greenhouse effect. Air pollution in Gothenburg has also improved. Mosses generally benefit from these conditions and this papers hypothesis is that the population of the species has grown because of these more beneficial conditions.

Vad skapar boendekvalitet? : Analys av småhusområden

The purpose of this thesis has been to signify what creates quality for the dwellers. Bycreating a definition of the term we have showed how well the qualitycriteria?s has been fulfilled in the newly built one family house area Pumpkällehagen in Viskafors.The questions the thesis gives answers to is: What is quality for the dwellers inhousebuilding of today? and How well have these quality aspects been carried out in tracthousing areas? These questions have taken us to our main goal: To describe what qualityfor the dwellers is and how well it has been carried out in a certain area.The literature review is describing what was published before the making of this thesis.From four different publications within the concept of quality an analysis template hasbeen enacted. This template has been used for our case study, but is also supposed towork in future analysis of tract housing areas.Interviews was carried out with the areas architects; Ola Nylander and Mattias Karlsson,as well as the client; Mikael Bengtsson. From these we have gathered their point of viewon the background of the area, as well as their view on the term quality for the dwellers.Our work has brought us to enact nine different quality aspects, which we considercreates quality for the dwellers:? The Non-measurable properties? The rooms relative connections? Sufficient and user-friendly property complements? The property complements connection to the apartment? Location of the apartment and connections to the environment? Opportunities of outdoor activities? Orientation and transportation within the area? The social unity? The cost of the apartment and its form of tenureFrom the case study, using the analysis template, we can state that Pumpkällehagen is avery successfully built area where most of our assessment criteria?s and quality aspectshave been fulfilled.

Småskalig biobränsleeldad kraftvärmeproduktion : teknik och investeringsutrymme

To achieve the requirements to decrease emissions of greenhouse gases by 20 % by 2020, Swedenneeds to increase its use of bioenergy. In doing so it seems natural that those who already haveaccess to large amounts of biofuels in the form of by-products such as straw, wood chips anddigestible materials take advantage of these assets locally. By combining production of heat withpower production at the farm it may be possible to not only reduce the direct use of fossil fuel forheating but also reduce energy costs.The purpose was to simulate different cases of using a small scale biofueled combined heat andpower plant for farm-based systems. A MatLab-model was developed and used to draw conclusionsabout the costs for production of heat and electricity with different conversion technologies.The model uses climate data to simulate the variations in heat energy demand on a day-to-day basis.The given heat demand is the base of the simulation and from this the possible electric output iscalculated. This study has focused on the impact of the following properties: electric-, heat- andtotal efficiency, fuel, fuel price and specific fuel requirements.

Habitat use and ranging behaviour of GPS tracked juvenile golden eagles (Aquila chrysaetos)

Throughout its wide distribution in the northern hemisphere, the golden eagle occurs in a diverse range of environments, e.g., mountainous, forest and open areas. The literature on juvenile golden eagles is limited, and this study provides further knowledge on habitat use and ranging behaviour during the post-fledging period in boreal Sweden. A total of 14 golden eagle juveniles were tagged with GPS transmitters during 2010 and 2011, and nine could be followed during the entire post-fledging period from fledging until migration. The juveniles fledged at the end of July and beginning of August and initiated migration during October and beginning of November. The length of the post-fledging period, until migration started, ranged from 49 to 97 days. During this period, the juveniles? distance from their natal nest and their GPS height increased with time as their flying abilities developed.

Ställtidsreducering med hjälp av SMED i pressgjuterianläggningar

To maintain production in high salaries countries and strength in competition against other companies, it is today more important than ever to maximize production, offer a wide spectra of products and be able to deliver on the customers desire of shorter and shorter delivery time. Flexible production and short time spent on die changes is vital to achieve these desires. The interest for die changeover time reduction grew in the same pace as the demand for increased product variety grew. SMED as a method of reducing time spent on die changeovers were developed in between 1950-1970, by the Japanese Shigeo Shingo.The purpose of this thesis work has been to investigate the result of SMED in a die casting facility, and compare the result from it with the result considering time spent on die changeovers when investing in new equipment. The goal is to implement a thorough investigation by using the SMED method at Tenhults Pressgjuteri AB and make a brochure that have to be simple to understand, in purpose to draw interest to the advantages of using SMED as a method.Commissioned by the Swedish foundry association Swecast, the work has been carried out by studying die changeovers at Tenhults Pressgjuteri AB, where filming and interviews with the operators have been included in the analysis.

Radon i flerbostadshus : Kartläggning av fastighetsförvaltarnas egenkontroll avseende radon

Radon is a hazardous substance that cannot be perceived by our senses. It has long been known that exposure to high radon levels for a long period of time will ultimately cause lung cancer. The Swedish Radiation Safety Authority estimates that 500 people die annually due to this. Although most of them are smokers, even non-smokers suffer from lung cancer caused by radon. The statutory value for radon in homes today is 200 Bq/m³.

Effekt på mark och gröda av olika bearbetningssystem, med och utan CTF

Swedish agriculture has gone through big changes in the latest 60 years. The farm sizes have increased, which has led to raised tractor and machinery sizes and therefore increasing problems with soil compaction. A method to reduce these problems is to implement controlled traffic farming, CTF. All field operations are then concentrated to specific tracks by using GPS guidance. The aim of this work was to study how the tillage regime, with or without CTF, affects the soil, with the main focus on macroporosity. In Säby close to Uppsala, and Alnarp close to Malmö, randomized block trials has been carried out, and the data has mainly been taken from these trials.

Design och konstruktion av mätuppställning för induktiv mätning av magnetisk spinndynamik

Development in spin dynamic occurs in the whole world because of therising demands on fast electronic storage for example hard drivesand RAM (Random Access Memory). Measuring the spin resonance of amaterial gives you the insight of the theoretical speed for amagnetic memory. This means the maximum storage speed is below thefirst resonance. All magnetic materials have different propertiesthat will inflict the resonance frequency which brings that theconstructors of memories need to know which magnetic material theywill use to obtain best results. In the market for normal users themaximum storage speed in a RAM memory is 1.6 GHz.

Torrefaction of biomass : a comparative and kinetic study of thermal decomposition for Norway spruce stump, poplar and fuel tree chips

Stump biomass is energy rich and stump harvesting for use as fuel become more and more interesting in Sweden. Swedish Forest Agency (2009) has estimated that stump harvesting in Sweden would respond to an annual energy supply of 57 TWh/year. However, stump has not been recognized as a bioenergy resource in Sweden. Suitable methods for pre-treatment of stump are probably of great importance to make it accepted as fuel. It is therefore rewarding to carry out an investigation in this area for stump. This report represents results from a diploma project, which was aimed to develop a fixed bed reactor for experimental study of biomass torrefaction, followed by TG analysis and kinetic modelling employing Ozawa method and different kinetic models including one-step and three-pseudo-component models.

INVERKAN AV HAVSF?RSURNING P? PROTONERBARA ORGANISKA F?RORENINGARAS EKOTOXICITET

Resulting from anthropogenic carbon dioxide emissions, average surface seawater pH is estimated to decline from today's approximately 8.05 to between 7.78 and 8.03 towards 2100. For ionisable organic pollutants, changes in pH can lead to a change in the degree of ionisation, which could influence the ecotoxicity of a compound by altering its bioavailability. In this study, potential changes in ecotoxicity of ionisable organic compounds resulting from ocean acidification are examined. This is achieved partly by conducting a literature review, analysing existing literature that investigates this relationship. Potential changes are also evaluated by examining marine ecotoxicity data for ionisable organic compounds on the watch list pursuant to Directive 2008/105/EC of the European Parliament and of the Council, as well as on the list of priority substances according to the 2022 proposal for amending the Water Framework Directive (2000/60/EC).

CE-ma?rkning av produkter under byggproduktfo?rordningen

The purpose of this study is to achieve an understanding of how a CE- marking process is conducted and to identify the relevant factors that must be considered in such a process. We have conducted our study at Lo?vhults Svets & Smide AB (Lo?vhults) in Skruv, Sma?land Sweden, which are manufacturing brackets for small covering constructions.To understand how a CE-marking process is conducted several documents and provisions have been reviewed to achieve a basic understanding and insight of the subject. It thus led to that guideline ETAG 015 were studied and the factors to be considered in the CE-marking of brackets were identified. Together with Jan-A?ke Johansson at Lo?vhults we agreed on four different brackets to investigate for a potential CE-marking.

Controlled traffic for grass silage production : an economic evaluation for dairy farmers

The farm management system controlled traffic farming (CTF) aims to reduce soil compaction by restricting the field traffic from agricultural machinery to permanent traffic lanes. Literature and empirical findings show that soil compaction and field traffic from heavy machinery may affect crop growth negatively, reducing crop yields. If grass-clover leys are subject to heavy field traffic the botanic composition might be altered, providing a lower clover content in the forage. Clover as a silage feed is rich in protein providing good conditions for high yielding dairy cows. Grass-clover silage production is generally associated with intensive field traffic.

Den goda platsen : om varför vi tycker mer om vissa platser än andra

How can man´s place preferences be explained? What aspects influence our experience of place? This essay attempts to define a good place to be drawing from sources of environmental psychology as well as other landscape theories and relating these findings to the landscape architect?s field of work. Physical place properties, like physical elements and their juxtaposition in space are examined in relation to place preferences as well as psychological properties, such as place attachment and place identity due to cultural or social aspects.There are strong cross-cultural similarities in our place preferences but there are also some differences. Natural elements, like trees or water, are widely preferred over man-made ones, like buildings, roads or fences.Man seems to be sensitive for the balance between different place characteristics, like the balance between ?soft?, natural, elements and ?hard? man-made ones or the complexity versus the legibility of place.

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