Sök:

Sökresultat:

46 Uppsatser om Gravel - Sida 1 av 4

Bibaggar i Halländska grustäkter

This report is a result of a first survey of Halland?s Gravel pits as an assignment from the County Administrative Board of Halland. The focus has been on Apalus bimaculatus, since the Swedish Environmental Protection Agency are creating a restoration program as it is red listed as Near Threatened. The purpose was also to get an overview of the pits since the County Administrative Board wants to continue this project. Apalus bimaculatus is easy to overlook since it is a short-lived beetle and it lives early in the spring.

Möjlig kvittblivning och eftermarknad av ridbaneunderlag - topplager

The aim of this study is to find information about what to do when riding arena footings are worn-out. Especially, the surface layer of riding arena footings is very interesting because of its importance of giving grip in every step for the horse, as well as shock ab-sorption. Generally, surface layers are containing several different parts in order to achieve desirable properties. These different parts can consist of organic material or in-organic material (mostly Gravel). Gravel and many other materials in the top-layer are environmental friendly, and therefore, easy to get rid of.

Flodpärlmusslans status i Laxtjärnbäcken : Effekter på flodpärlmusslan av sedimentbelastning och förekomst av bäckröding

The aim of this present study was to determine and evaluate whether the presence of brooktrout (Salvelinus fontinalis) and sediment load may be a threat against the reproduction anddistribution of freshwater pearl mussel (Margaritifera margaritifera) in a creek located innorthern Sweden. Freshwater pearl mussel is an endangered species and is dependent ofbrown trout (Salmo trutta) to reproduce. Therefore there are concerns of indirect effects onthe population of pearl mussel by competition between brown trout and brook trout. Ditchesfrom a nearby Gravel road have been fixed to lower the sediment load into the creek. I tried toevaluate this action plan.

Skydd mot yterosion i slänter av finmorän

Slopes in fine till soils are exposed to surface erosion due to rainfall, snowmelt and upland water sources. Large areas of road slopes are therefore covered for surface erosion protection. Preventive methods like ditches and trenches are also being used. Silt tills are particularly troublesome since the water can bring the soil into suspension and cause mudslides. Different methods for erosion protection have been studied in this work, with the emphasis placed on rockfill covering. The need for and the dimensioning of this type of covering has been examined in literature and field studies.

Gullrisbock (Phytoecia nigricornis) i grus- och sandtäkter i Halland.

This dissertation is done as a preparatory step for the action plan of environmental protection shall issue to preserve the Phytoecia nigricornis in the country when it is red-listed and classified as vulnerable (VU). My task was to investigate the prevalence of the Phytoecia nigricornis in Halland County. They wanted to see if it existed in Halland (Ehnström, 1999). If it did not exist they wanted to know how to improve its habitat.the Phytoecia nigricornis is difficult to inventory because when it is larvae it lives in the roots and lower parts of the trunk of the Solidago Virgaurea plant and the adult beetles only keeps to Solidago Virgaurea by mating and egg laying and larval caterpillars when they hatch (Bily, 1989; Molander, 1999). Often it is overlooked or missed, and one question was whether it existed  in the whole country or only in those parts where it was previously found in, Skåne, Blekinge and Östergötland (Ehnström, 1999).One problem for the Phytoecia nigricornis is that their habitats is declining.

Bottensubstrat och dess inverkan på reducering av BOD5, COD och TKN i lakvatten genom konstruerade rotzonsanläggningar : En pilotstudie vid Univates, Lajeado ? RS Brasilien

Treatment wetlands been showed efficient for reducing pollutant in waste water. In Lajeado ? RS, Brazil the landfill has poor leachate water treatment. It is necessary to supplement the treatment plant because they need to reduce BOD, COD and nitrate of the water going to recipient. A subsurface flow wetland (SSF) can be a good choice.  In order to be able to design an efficient SSF it is important to understand how the grain sizes of a substrate affect the reducing of pollutants in waste water.

Fälttest av en ny metod att med objektiva mätmetoder karaktärisera egenskaperna hos ridunderlag- en pilotstudie. :

Background Research concerning footing and its contribution to injuries has been conducted primarily in racing Thoroughbreds. Studies in UK and Japan indicate that some specific factors could be responsible for an increase in performance-associated injuries. Researchers in Sweden have performed studies on Standardbred trotters. More research is needed to be done on equestrian sports since requirements on footing are not exactly the same in riding and trotting horses. The lack of scientific evidence on the construction of equestrian surfaces has lead to anecdotal validation of designs.

Stenmjöl eller naturgrus i betong : En jämförande studie

 The objective of this thesis is to examine the difference in workability in fresh concrete, when crushed fine aggregate replaces natural Gravel. The shape of the fine aggregate,  packing and flow of six crushed material and three natural materials will be determined by easy studies, the results will be compared with a slump cone test..

En jämförelse mellan TLS och UAV-fotogrammetri : Inmätning av hårdgjorda ytor

At present day there are several different methods for measuring of paved surfaces.The most common methods today are measuring with a total station, the GlobalNavigation Satellite System (GNSS) and terrestrial laser scanning (TLS). Recently thedevelopment of unmanned aerial vehicles, known as drones, has increasedexponentially and today there are several ways of using drones for measuring surfacesby photographing and laser scanning.This thesis contains a comparison between the methods terrestrial laser scanning(TLS), and unmanned aerial vehicle photogrammetry (UAV). The measurements havebeen applied on two different test surfaces, one of asphalt and one of Gravel. Thepurpose of the comparison is to investigate whether the airborne photogrammetry isequivalent accurate in its height levels as the terrestrial laser scanning. For thecomparison to be more extensive, these two methods have not only been comparedin precision but also in the areas of ease of use and economy.The precision was analyzed by comparing the height levels in randomly placed controlpoints on the test surfaces.

Tidsstudier i kalvuppfödning :

Swedish agriculture stands in front of big changes the whole time. As a milking producer you have to adapt and develop the company to these changes and find the best solution. This potential is easy to find if you compare your company with other similar companies. Labour cost is the biggest cost in milking production after the cost for food. Today it is rather easy to measure how many hours per cow different system of cow houses needs, but we do not know so much about how many hours it takes to breed a calf. To learn more about the labour time with the calves during the first time after the calf was born, I made time studies on five different farms with calf hutches, automatic milk system, large calf boxes, and smaller calf boxes with teat buckets.

Sammanvägda avrinningskoefficienter i rationella metoden : en jämförelse mellan idag och 1970-talet

Storm water is rain and melted snow that runs off, primarily from impervious surfaces.Future storm water management is facing the challenges of increased precipitation, asclimate changes, and increased areas of impervious surfaces due to the expansion anddensification of the cities. Impervious surfaces reduce the potential for water to infiltratein the ground leading to increased surface runoff and higher peak discharge.The runoff coefficient is closely related to the percentage of impervious surfaces andrepresents the maximum percentage of a catchment that can contribute to runoff. In thisstudy, the objective was to evaluate the weighted runoff coefficient for three differenturban types; apartment buildings, townhouses and residential areas and a comparisonbetween today and the 1970`s was made.The runoff coefficient was determined by manual mapping of the different surface typesin each area based on data in the form of orthophotos and aerial photographs. The surfacetypes that were mapped were asphalt, permeable areas, tiles, sand/Gravel and roof.Tiles and sand/Gravel were the most difficult surface types to map. In order to see towhat extent these categories influenced the weighted runoff coefficient a sensitivityanalysis was carried out and the runoff coefficient based on surface type was changed indifferent scenarios.The results of the sensitivity analysis showed that the surface types tiles and sand/Gravelhad little impact on the weighted runoff coefficient which in mainly due to the fact thatthe percentage of these surfaces types of the total area is small.The result of the study showed that the largest change in the runoff coefficient occurredin residential areas where the increase in the percentage of impervious surfaces causedby new roofs in the form of porches and garages and from paved or tiled driveways.

Avsättningsmöjligheter för slaggrus från avfallsförbränning vid Åmotfors Energi

The incineration of waste is steadily increasing in Sweden and so is the production ofashes. The bottom ash has for many years been used as construction material inlandfills. Now many of the nation's landfills are closed and there is a great need to findanother beneficial use for the ash. Bottom ash is a Gravel-like material and with itsmaterial properties it can replace natural Gravel in parts of roads and surfaceconstructions. Today this use is only approved within landfill areas where leachate iscollected and checked.

Avsättningsmöjligheter för slaggrus från avfallsförbränning vid Åmotfors Energi

The incineration of waste is steadily increasing in Sweden and so is the production of ashes. The bottom ash has for many years been used as construction material in landfills. Now many of the nation's landfills are closed and there is a great need to find another beneficial use for the ash. Bottom ash is a Gravel-like material and with its material properties it can replace natural Gravel in parts of roads and surface constructions. Today this use is only approved within landfill areas where leachate is collected and checked.

Bottensubstratets inverkan på föryngring av Flodpärlmussla

The freshwater pearl mussel (Margaritifera margaritifera) is threatened throughout its range. There has been a substantial decline of the species and one major reason is habitat degradation. We investigated how the substrate composition of the bottom floor affects the regeneration of the mussel by analyzing data from the Västerbotten County Board?s inventory of the freshwater pearl mussel. The results implied that fine material such as fine sediment and sand might be detrimental to regeneration whereas Gravel and boulders and in particular stone seem to be beneficial.

Att Synliggöra det Osynliga : GIS som verktyg i sökandet  efter bosättningsområden från bronsåldern på Gotland

In this bachelor essay an attempt is done, to recreate a probable Bronze Age landscape on Gotland, with GIS as a tool. The landscape on Gotland is situated with many different monuments dated Bronze Age, such as cairns and stone ships. In creating of the maps, two possible shorelines contemporary with the Bronze Age have been calculated and marked on the maps. Furthermore, peat lands have been drawn upon the maps, by using the information from geological maps.A landscape variable have been compared between Bronze Age places and Early Iron Age houses; the soil type. On Bronze Age places Gravel is the most common, while moraine marl is the most common on places with Early Iron Age houses.From a selection that were made, all Bronze Age places where within 3 km from the water, either the recreated shoreline or peat land.

1 Nästa sida ->