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254 Uppsatser om Density - Sida 1 av 17

Inverkan av nederbörd, temperatur och frost på årsringens egenskaper hos boreal tall (Pinus sylvestris L.) :

The wide distribution range of our boreal pine (Pinus sylvestris L.) provides a great variation in growing conditions and climate/weather factors that influence the wood development of the trees. A great number of extensive studies have been conducted over the years in order to clarify growth trends of this and other species over more or less wide-ranging areas. In this thesis effects of weather factors were instead compared between different forest stands from the about same geographical location. The effects of precipitation, temperature and frost on the year ring characteristics of pine were studied in the research forest of Svartberget Vindeln, in northern Sweden. The stands differed in site index and silvicultural treatment; fertile ? high stem Density, fertile ? low stem Density, poor ? high stem Density and poor ? low stem Density.

Social hållbarhet och förtätning : en kritisk studie i förtätningens sociala paradoxer

Densification is one of the urban visions for sustainable development - a vision that has become a part of the solution to the unsustainable sake dilemma. With the dense city land will be saved, energy consumption reduced and social cohesion improved. The dense city is considered to be ecologically, economically and socially sustainable. Applying an urban design concept has thus proven to be problematic. Density has been found to be a complex concept which is far more complicated than measuring how much built surface that needs to be covered. It is also not disputed what different degrees of densification mean and whether densification in itself is sustainable.

Jämförelse av fyra rundbalspressars packningsförmåga som funktion av grödans torrsubstanshalt :

To succeed, and make money at your animal production you need to feed your animals with high quality fodder. Other condition to succeed is that you keep your production costs at a minimum. To be able to produce baled silage at a low cost it?s very important that the bales have a high Density. Density is measured in kg dry matter (DM) per cubic meter. The purpose with this report was to learn more about making silage in round bales and to how much the bale Density varies between different brands of round balers.

Röjningsförbandets betydelse för avverkningsekonomin i södra Sverige :

The aim of this work is to demonstrate how the net present value (NPV) at the time of the first thinning depends on the spacing after pre-commercial thinning, and show how net value from first thinning in same stand is influenced. This study is performed with models based on non-distant dependent growth models for single trees. Two different growth models have been used, one for cleaning (pre-commercial thinning) and one for thinning. The first one yields stem Density distributed over diameter classes. In the second one, (the thinning model), it is possible to choose when thinning should be done, the thinning method, thinning grade and numbers of thinning.

Identifiering av gallringsbehov med hjälp av flygburen laserskanning :

Thinning is one of the most important silvicultural activities in middle aged forests, partly to minimize damages and partly because it leads to earlier harvesting revenues and increases the value of the remaining trees. There are many different indices used to describe stand Density and thereby the need of thinning in forests today. Studies have shown that forest variables can be estimated with high accuracy using airborne laser scanning and it is likely that the method could also be used to estimate forest Density indices. In this study, the possibility of using the forest Density index ?H² to determine and map priorities for thinning operations for a forest area was examined.

Hur påverkar förtätningen stadens grönstruktur? :

Urban Density is not new, but rather one side of the continous processes of change underway in the city. During the urbanizing boom of the industrialization, when the cities grew bigger, the first spaces to be built on were vacant and planted areas in the interior of the district. The gardens that once were there were replaced by yardhouses. The idea of urban Density is that a dense city means less distance between residential areas and workplaces, resulting in fewer shipments and travelers, which ultimately leads to lower energy consumption and lower emissions. Urban Density may lead to shorter distances, but not necessarily. In the wake of urban Density the greenstructures of the city is shattered. The possibilities for green areas to contribute to the health of the city and its inhabitants is dramatically reduced.

Röjning på snö och röjning på barmark : effekter på produktivitet och kvarvarande bestånd

Approximately 4000-5000 hectares, of SCA´s forest land area in Västerbotten, are in need of pre-commercial thinning (PCT) every year. Within the management district, the areas annually treated with PCT must increase, in order to decrease the area with an urgent need for PCT. This can be done by employing more forest workers or entrepreneurs, by mechanized PCT or by an extended season for PCT. Positive experiences from a private forest owner, who started to carry out PCT when the first snow came and then continued for several months, gave an idea to investigate the possibilities to prolong the season of PCT. The purpose of this experiment was to compare PCT carried out when there was snow on the ground with PCT performed when there was no snow on the ground.

Bastu-frigidarium,energieffektivt system för återhämtning

Sweden is considered to have one of the world's highest animal welfare standards in agriculture. Despite this, there are shortcomings in animal husbandry. One example is overcrowding, which is a way to increase stock size without making costly investments in the buildings. It can be carried out systematically to increase profitability or due to, for example uneven calving during the year. The European Commission criticizes the fact that stocking Density is not controlled under Swedish welfare inspections.

UTVÄRDERING AV ARBETSMETODER OCH KONTROLL AV BELÄGGNINGSGRAD BLAND MJÖLKKOR I LÖSDRIFT I HALLAND

Sweden is considered to have one of the world's highest animal welfare standards in agriculture. Despite this, there are shortcomings in animal husbandry. One example is overcrowding, which is a way to increase stock size without making costly investments in the buildings. It can be carried out systematically to increase profitability or due to, for example uneven calving during the year. The European Commission criticizes the fact that stocking Density is not controlled under Swedish welfare inspections.

Jämförelse mellan sådd och naturlig föryngring av tall i Härjedalen

The purpose of this study was to compare naturally regenerated Scots pine (Pinus sylvestris (L.)) against seeded Scots pine in terms of benefits and differences. An inventory was performed at a number of different sites, 4 ? 6 years after soil scarification and data on the number of new established plants, their height growth as well as ground-line diameter was collected. Information about site conditions such as altitude, quarter exposure and frost risk was also collected. A review of previous studies was conducted in addition to the field study.

Cassava as an additive in biomass fuel pellet production :

In this study, the effects of using fine milled cassava stems as an additive in biofuel pellet production was compared to the effects of refined starch addition. The bulk biomass fuel raw material, to which the additive was added, was a blend of spruce and pine sawdust. An experimental design in the factors cassava/starch content, moisture content and material temperature was used. Measured responses were pellet bulk Density, pellet durability, amount of fines, pelletizer motor current, pellet temperature, die temperature and CV for pelletizer motor current (a measure of process stability). Each response was modeled by multiple linear regression (MLR).

Flottledsåterställning i norra Sverige: : effekter på habitatkvalitet och populationstätheter av juvenil öringar (Salmo trutta L.)

In an effort to evaluate the effects of restorations of float ways on population Density of stream dwelling fish in relation to the changes in habitat, I studied the physical habitat restored and channalized sites and their population Density of brown trout (Salmo trutta L.) in three streams in the municipality of Sorsele. The differences between the channalized and the restored sites where most noticeable regarding substrate which where generally coarser in the restored sites. The analyses showed that the proportion of habitat that where suitable to the age class 0+ where significantly lower in the restored sites compared to the channalized sites. Regarding age class ?2+, no statistical differences in habitat quality were found.

Akustisk mätning av U-värde

This pre-study investigates the possibility of U-value measurements through an acoustic method. A hypothesis about an acoustic model built on acoustic theories combined with U-value theories is presented to answer the questions: ? Can U-value theory be combined with acoustic theories? ? Can the coefficient of heat be affirmed trough an acoustic measurement? The idea for this dissertation begun with a logical idea in mathematical similarity, between the coefficient of heat transmission units and sound intensity units. The U-value theory is based on assumptions such as initial resistance for inner walls and initial resistance for outer walls. The resistance in the material is interpreted through sound intensity theory. The argument is built upon mass law theory, which means if the frequency or thickness of the material layer doubles it implies an increase of sound reduction by 6 dB.

Visuell utvärdering av frekvensmodulerat raster på obestruket papper.

This thesis investigated if a combination of increased under colour removal (decreasing the total ink limit), normal andincreased Density and modern FM-screening could be used to provide a visually better print on uncoated and coated paperin comparison with AM-screening using the same conditions.Two different test groups (one with graphic background, the other with no graphic background) were asked to a visuallyassess the quality of the prints presented in a pair comparison using a reference image.The results show that the FM-screening did not obtain any significant visual difference in comparison with AM-screening,regardless of paper types and Density levels. In general however, prints on coated paper were graded higher..

Fåglar i urbana miljöer : kvaliteten på urbana habitat och om beståndstäthet är ett bra mått på habitatkvalitet

The urbanization of the world is increasing. How it affects bird populations have been well studied during the last decade, and comparisons between urban and non-urban habitats have been carried out. A common method for measuring habitat quality is to calculate the population Density. This method is easy to use, but have been criticized during the last couple of years. In this study, data of population densities was compared with data on reproduction success.

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