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681 Uppsatser om Soil moisture gradient - Sida 39 av 46
Etableringsstrategier för spannmål : en studie av investeringsbeslut i maskinsystem
In order to produce grain in an economically rational manner numerous decisions have to be made. One of these decisions is what tillage system to use. The cost of the tillage system is a large part of the total cost in grain production. Different tillage systems result in different distribution of fixed costs, operating costs and timeliness costs. The price of the produced grain and cost of inputs also affect the best way to produce grain.
Rotinträngning i VA-ledningar : en fallstudie i Växjö
Mitt syfte var att, genom min uppsats få en ökad förståelse för de faktorer som påverkar när och hur en rotinträngning uppstår, och genom denna förståelse försöka utarbeta rekommendationer för att både minska risken för rotinträngningar och hitta lämpliga lösningar på befintliga rotproblem.
Uppsatsen består av två delar, en litteraturstudie och en fallstudie. Litteraturstudien bygger på relevant litteratur som ska ge en bild av problemen med träd i städer och tidigare gjord forskning inom ämnet. Fallstudien är gjord på fyra olika områden i Växjö som har problem med rotinträngningar i VA-ledningar. Där det har gått har jag jämfört tidigare filmningar med filmning som gjorts nu i höst för att få en uppfattning av hur stort problemet med rotinträngningar är i de valda områdena.
De fyra områdena i min fallstudie har alla olika rotinträngningsproblem, och därigenom olika rekommenderade åtgärder. Alpgatan består av privatägda träd med endast ett fåtal större rotinträngningar.
Påskön. Myten om Rapa Nui
This essay will examine the historical picture of the island Rapa Nui as it is portrayed in popular science and in ecohistorical literature of the university of Gothenburg. This historical picture states that the inhabitants of the island cut down a lot of trees in the process of transporting the big and heavy statues, moai, from the quarry to the platforms along the coastline of the island. During this process all trees disappeared and resulted in soil erosion. The cultivation was destroyed and brought hunger to Rapa Nui. The following rivalry for food led to a situation of war followed by a cultural collapse.
Erfarenheter från Olika Produktutvecklingsprocesser vid Utvecklingen av en Atmosfärisk Vattengenerator
This Master of Science thesis was completed at the Department of Machine Design at the Royal Instituteof Technology in Stockholm in collaboration with Lund Faculty of Engineering, Luleå University ofTechnology and Stanford University. At Stanford University a global product development project wasrealized as part of the course ME310. The project was initiated by the American company ImmerseGlobal whose vision was to develop a new type of Atmospheric Water Generators, a machine that absorbsthe moisture in the air and via a water system transforms it to pure drinking water. The project was partlyfinanced by the Product Innovation Engineering program, a Swedish research and development programfor increased innovation capability in organizations.In parallel with the global project in the ME310 course the product development process was studied inorder to compare it with a product development course at the Royal Institute of Technology, IPU. Thetwo courses are similar to each other in several aspects.
Grundvattenmodellering av föroreningstransport : Ett uppdragsanpassat beräkningsverktyg
Grundvattenmodellering av föroreningstransport ? Ett uppdragsanpassat beräkningsverktygEmil Friberg Målet för detta arbeta var att bygga upp en modell i modelleringsprogrammet MODFLOW för spridning av förorenande ämnen i grundvattnet. Syftet med modellen var att finna en balans mellan den mycket enkla modellen som Naturvårdsverket har satt upp för förorenad mark och en fullskalig platsspecifik modell.Utgångspunkten var att studera litteraturen för att finna lämpliga generella parametrar som beskriver föroreningstransport i grundvattnet. Tre genomförda uppdrag med förorenad mark användes som referenskälla, men även för att evaluera den framtagna modellen. Föroreningarna som förekom i dessa uppdrag och som studerades i detta arbete är bensen, PCE och arsenik.
Kolbalansen vid olika skötselstrategier för skogen på Tagels fastighet.
Since the 19th century the concentration of CO2 in the atmosphere hasincreased by 40 percent as an effect of the use of fossil energy sources.Increased concentration of CO2 will likely lead to increased temperature,changes in precipitation, rising sea level and increased frequency of extremeweather like storm events. A step to reduce emissions of CO2 and mitigateclimate change, for the property of Tagel, can be to adopt new silviculturalstrategies and analyse which is the most effective. As a result of that, threescenarios was produced, business-as-usual (BAU), increased set aside landand energy. An introduction of windpower at Tagels estate (property) andeffects on carbon balance was also examined. By using the Heureka systemand LCA-analysis in this study, it showed that the scenario of increased setaside land was the most efficient way to reduce carbon dioxide (CO2)emissions for the analysed period of 100 years.
Samband mellan vattenkemi, ekosystemstruktur och -funktion i två dagvattendammar
Dagvatten bildas då regnvatten inte kan infiltrera marken på grund av hårdgjorda ytor såsom vägar och hustak. Dagvatten är ofta kontaminerat av metaller, näringsämnen och andra föroreningar och bör därför renas i en anläggning innan det når recipient. En allt populärare metod för att omhänderta dagvatten är att anlägga dagvattendammar. I dammarna renas det inkommande dagvattnet genom flera olika processer, varav sedimentation är den viktigaste.
År 2006 startades projektet NOS-dagvatten (Norrortskommuner i samverkan) i syfte att erhålla ökade kunskaper om funktionerna hos fem dagvattenanläggningar i Stockholmsområdet. I detta arbete utreds sambandet mellan den kemiska vattenkvaliteten och ekosystemens hälsostatus i Ladbro- och Tibbledammen som ingår i NOS-dagvatten.
Östra Kvillebäcken En gröna stadsdelen? En fallstudie över Östra Kvillebäcken i Göteborg
The study is a case study about the green urban district, East Kvillebäcken, located in Gothenburg, Hisingen. East Kvillebäcken is the first urban district in Sweden with ambition to build sustainable according to the certification system Miljöbyggnad, which make it a pioneer project. The purpose is to investigate the upcoming and the meaning of the green urban district in East Kvillebäcken and show how public employees think the urban district can affect social, ecologic and economic aspects in the area. Dialogue interviews were done with four public employees, one estate agent and two residents. Local plans and other authority documents were used to get a deeper understanding for the case study.
Köpa jordbruksmark i Ukraina :
We have chosen to write our examination essay about Ukraine, we wanted to find out
what kind of possibilities there is to run a farm there, and also find out what kind of
problems that might arise. Ukraine is still heavily influenced by Russia and the legacy
from the former Soviet Union. The agriculture today looks pretty much like it did before
the collapse of the Soviet system. There are large governmental or cooperatively owned
farms. The large farms have to deal with bad cash-liquidity and they often have trouble
getting a hold of seed and artificial manure to their whole acreage.
Förstudie till våtmark i Rimbo : Design för optimal hydrologi och kväverening
The euthropthication of the Baltic Sea is a threat that is beginning to be taken seriously by the governments concerned. In Sweden, regulations concerning the allowed nitrogen (N) concentration in the effluent water from wastewater treatment plants are being tightened up. The Rimbo wastewater treatment plant has been imposed to reduce the annual mean concentration of total N in the effluent water to levels below 15 mg l-1. A more and more common way to reduce the nitrogen level in wastewater is to let the water pass through a wetland. This study investigates the possibility to build this kind of wetland at the outlet of the Rimbo wastewater treatment plant.A prestudy of the topography, soil characteristics and groundwater flow indicates that the land area in question is well suited for the construction of a wetland.
Kaliumgödsling på torvmark - effekt på tillväxten hos planterade granar (Picea abies)
Peat lands are a great potential resource for increased forest growth in Sweden, there are approximately 6.5 million hectares of peat lands, whereof around 70% produce less wood than one m3sk/ha and year and are therefore classed as forest waste land. There are over 200 000 hectares of peat land that is already drained and wooded, and that may be suitable for fertilization. Forest production on peat soils usually requires drainage and fertilization. Dewatering requires ditching the area, so that the roots can have access to oxygen. Nitrogen is often abundant in the peat but other nutrients; especially potassium is in short supply. The purpose of this work was to examine the effects of potassium fertilization on the growth of spruces that were planted on drained peat land and how different amount of fertilizers affects the growth. Potassium deficiency is strongly growth inhibiting, since potassium is important for substance transport in the tree. Potassium is also important for the carbohydrate formation, and because increasing the sugar content of the cells constitutes a lower freezing temperature does potassium availability in the soil play a major role in the winter resistance of many species. Potassium is not found in any organic compounds in the tree, but is present in cell and tissue fluids. A fertilization trial was started in 1978 in Siljansfors Experimental Forest. The plots in the experiment were fertilized with different amounts of potassium and one plot was left without fertilization. All plots that were fertilized with potassium grew considerably better than the unfertilized plot. The difference in production between the unfertilized plot and the plot that received the most potassium was 7.2 m3sk/ha and year. The unfertilized plot can still be classified as waste land. The theoretical production capacity was estimated using a Swedish system for site quality estimation of wetlands after ditching (dikningsbonitering). The plot with most potassium produced after fertilizationaproximately in level with theoretical estimations. Key words: Peat land, Fertilization, Ditching, Growth, site quality..
Retention of stumps on wet ground at stump-harvest and its effects on saproxylic insects
Low stumps represent on their own up to 80% of the dead wood remaining on clear cuts and therefore supply suitable habitat for saproxylic insects i.e. insects depending on dead wood for their survival. Recent stump harvesting activities threaten this substrate of ecological importance and increase the anthropogenic negative impacts on these species. Because of technical and environmental reasons (nutrient leakage, erosion) guidelines for stump harvesting recommend to retain stumps standing in wet parts of clear cuts. However, stumps in wet positions might not be a satisfactory substrate for saproxylic insects and therefore might not be as much used as stumps in dry positions.
Mikrosensorer i nätverk
The purpose of this thesis is to investigate the possibility to make small, cheap and ultra low power sensor platforms, connected in wireless networks for monitoring of home and industrial environments. The concept is based on ideas from our supervisor, Jerry Lindblom. The developed system consists of a generic platform for different sensors, a receiver and software. A GPRS module from RO Rollytech AB and a database from Gema Industri AB have been modified and used to demonstrate an example of a complete system. To the platform, it is possible to connect any resistive sensor and any sensor that can act as a switch.
Klimat i djurtransportbil med slaktgrisar sommartid : jämförelse mellan naturlig och mekanisk ventilation
SAMMANFATTNING
Uppskattningsvis transporteras 171 miljoner grisar inom EU varje år, varav ca 3,5
miljoner i Sverige. Grisarna kommer, under hela förloppet från förflyttningen från box i
stallet till bedövningen i slakteriet, att utsättas för stressande moment. Orsakerna är
bland annat omgrupperingar, nya miljöer, vibrationer i bilen samt, speciellt under
sommaren, värmestress.
Temperaturen i djurtransportbilen är en nyckelfaktor som dessutom kan förstärka
effekten av andra stressorer. Lastning i höga temperaturer ökar risken för värmestress.
Värmestress innebär att djuren får allt svårare att avge sin värme. Även den relativa
luftfuktigheten har betydelse, framförallt vid temperaturer över 30°C.
Det är ventilationen i transportbilen som ska transportera bort värme och fukt från
bilen.
Hårdhetsvariation i grundvatten längs Badelundaåsen mellan Leksand och Avesta
Water hardness indicates the concentration of calcium and magnesium ions in water. Water with high concentrations of these ions is described as hard water and water with low concentrations is described as soft water. Water that is too hard or too soft can lead to technical and economical problems. In collaboration with Midvatten AB, groundwater hardness in the Badelunda esker between Leksand and Avesta has been mapped, and an attempt has been made to explain the variations. For this purpose, different GIS programs, such as ArcView, ArcInfo, IDIRISI, and one geochemical modelling program, PHREEQC, has been used.