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416 Uppsatser om Carbon dioxide gradient - Sida 12 av 28
Aktivering av en dissolvingmassa med enzymer före en konventionell viskosprocess
In conventional viscose manufacturing, a large amount of carbondisulfide is consumed. This amount has to be decreased to keep the production cost down and to reduce the environmental impact. The purpose with this work was to show if an enzyme treatment of a dissolving pulp could increase the degree of substitution in the viscose so that the amount of carbon disulfide consumed in the process could be decreased. Previous investigations by Kvarnlöf (2007), Engström et.al. (2006) and Henriksson et.al.
Små skogliga vattendrag i Värmland - Generell beskrivning, förekomst av traktorspår samt spårens inverkan på bottenfaunan :
Modern forestry requires a high degree of machine traffic for clear felling and scarification operations. The machines most frequently used are big and the traffic often results in tracks on the forest ground. There are many small streams running through a forest, in connection to logging operations, machines might cross these frequently. These crossings could result in the erosion of fine particulate inorganic matter, which ends up in the stream. The aim of this thesis was to give a general description of small forest streams of order-one in the county of Värmland and to determine the frequency of machine tracks in small streams.
Miljöekonomiska analyser av smog och luftföroreningsproblemen i Kina
Rapid economic development and urbanization has led to an improved standard of living for the Chinese people. Meanwhile, a series of environmental problems have also appeared and smog, in particular, has caused the Chinese people to realize how serious the situation is. Smog has seriously affected normal economic activities and people's everyday lives, resulting in financial losses, increased mortality and disease. How to handle the smog becomes particularly important. The purpose of this study is to describe and discuss the underlying causes of two sources of pollution, particulate matter and sulfur dioxide, as well as what drives individuals' and firms' environmentally destructive behavior.
Ackumulation av CO2 och CH4 i istäckta boreala sjöar : Hur förändras ackumulationen i sjöar påverkade av avverkning jämfört med referenssjöar?
The aim of this report was to quantify the accumulation of carbon dioxide (CO2) and methane (CH4) in ice-covered lakes in winter (October-March) during three consecutive years, and to assess whether the concentrations of DIC and CH4, as well as the ratio DIC:CH4 differs between years and between lakes affected by clearcutting and untreated reference lakes. Water- and gas samples were collected from four boreal lakes (two affected by clearcutting and two untreated reference lakes) located in Västerbottens inland in spring. The lakes were found to accumulate on average 91, 55, and 84 mgCm-2d-1 during winters 2012-2013, 2013-2014, and 2014-2015, mostly originating from CO2. The concentrations of DIC (autumn and spring) were higher in the affected clear-cut lakes compared to reference lakes for all years, including the reference year (2012-2013) before clear-cutting. No such difference was found for CH4 or the ratio DIC:CH4.
Gaspotentialen i en deponi, idag och i en framtid :
Deposited waste material degrades within a short period in anaerobic environments. The
methane gas that is formed provides a harmful contribute to the greenhouse effect, 23 times larger impact than carbon dioxide. It is therefore desirable to minimize the emissions of methane gas from landfills. This may be achieved by drain the landfill of gas.
In this thesis the amount of produced methane gas at the landfill at Örebro has been
calculated. Estimations have also been made of the amount of methane gas that might be
produced in the landfill in the future.
Underlag till energieffektiviserande åtgärder i nätstationer
Umeå Energi are working towards a goal, that in the year of 2018, they will be completely climate neutral. As a part of this, one target is to reduce their grid losses by 4 % of the 2012 level, which corresponds to an overall reduction of the grid losses of just over 1.7 GWh. In many residential areas, the distribution grid is designed and rated for electric heating as the heating in the houses. As many of the houses later has been converted to other types of heating, their electricity use has decreased and the total power output from many of the secondary substations has decreased significantly. Because of this, many of these stations today are well oversized, which in turn means that the energy losses in these stations are unnecessarily high.In this degree project, 25 secondary substations have been studied, all located in residential areas in and around central Umeå.
Valsningsteknik för extremt höghållfasta tunna stål
New high strength steels require improved cold rolling techniques. The aim of this degree project was to develop a new and money saving cold rolling technique to manufacture steel strip for saw blades. The work is based on earlier rolling experiments made with a high carbon steel grade at LuCoil Steel AB. The work also focused on the mill requirements to cold roll high strength steels. The results show that LuCoil?s existing cold rolling mill was actually designed for rolling low carbon steel.
Bokhögstubbar i Klåveröds strövområde : utbredning, egenskaper och betydelse för rödlistade vedlevande skalbaggar
Lack of dead wood is the main cause of decaying or loss of populations for many
forest species. To increase the amount of dead wood is a prerequisite to maintain
biodiversity in forests of northern Europe. In summer 2006 the recreation area
Klåveröd, at Söderåsen in Skåne, Sweden, has been inventoried for high stumps
(snags) of beech, (Fagus sylvatica). The result of the inventory has been compared
with data of the real estate and forest management directories from the owner,
region Skåne. The results have also been matched with the results from an
inventory of saproxylic beetles in 2005, performed with windowtraps on selected
snags both in the area and the adjacent national park Söderåsen.
594 snags were found on 747 ha.
Radialtätning till Retarder
This thesis has the overall objective to develop the optimum sealing system between the retarder and transmission. Today, there is a pressure-relief and two radial seals separation between the retarder and transmission. It has been found that carbon residue formation may occur between retarder axle and seal lips with, in some cases, leakage as a result.We have in this thesis tried to explain the phenomenon of carbon residue, how it is formed and why it can be seen just on the seals? A rig test was conducted where we show how friction, speed, transmission temperature and mitigation phases of the retarder affects temperatures in the sealing environment. Factors affecting the coke structure are reported, together with proposals for measures that provide a mitigating seal environment.
Miljöbyggnad i ombyggnadsprocessen : Miljöcertifiering av Jakobsbergsskolan i Kristinehamn
Climate change is an increasingly widely known concept. In the EU the construction sector is responsible for more than a third of the carbon dioxide emissions and 40 % of the total energy use. In Sweden, measures have been taken to prevent this climate change. By 16 targets, three of which can be linked to the construction sector, Sweden will reduce the negative trend. None of the three goals with relation to the construction sector will however be achieved before 2020.
Svält vid akut diarré hos hund, beprövad forskning eller gammal vana?
The idea for this project was initiated together with one of the leaders in the forest, paper and packaging industry. To get through an A/R CDM process the company is exposed to the risk of failing the process or that the overall costs will exceed the benefits of the project. This would delete the incentives to invest in GHG removals compared to purchasing emission allowances on the carbon market. The questions that have been raised and needs clarification in the thesis are the following:? From a company perspective, what are the incentives for implementing Forest Clean Development Mechanism (CDM) projects?? What is a likely financial outcome of a reforestation CDM project on degraded land in the Guangxi province of the Peoples Republic of China?? When does an investment like this break even with the cost of buying market based carbon emission allowances? The objective of this master thesis is to carry out a research about the incentives for forest, paper and packaging companies to invest in reforestation through the clean development mechanism.
Etanolmetabolismen ur ett alkoholistperspektiv : Kemin vid nedbrytning av etanol i kroppen, dess betydelse för kroppens kemiska processer i övrigt samt dess betydelse för hälsa och sjukdom
The present study discusses the metabolism of ethanol in the human body from the ingestion of ethanol to the excretion of its break down products water and carbon dioxide. Ethanol is a small molecule, soluble in water as well as in organic solutions. It is quickly distributed to every section in the body, where it exerts a direct toxic effect on the cells. Ethanol cannot directly leave the body efficiently so it needs other metabolic pathways. The molecule is metabolized by oxidation, predominately in the liver.
Produktutveckling och prestandatest av ett vattenvärmedrivet torkskåp : Jämförelse mellan tre utvecklade versioner av ett vattenvärmedrivet torkskåp
AbstractElectricity consumption is a globally increasing problem caused by the high share of electricity produced in coal power plants. These contribute to high carbon emissions when only about 1/3 of the heat generate electricity and the remaining 2/3 of the heat cools off. Combined heat and power plants (CHP) have high efficiency because they use the residual heat for domestic heating. The CHP plant often use fuels from renewable resources, giving them a lower carbon footprint, but are also depending on the heat demand. If electric powered products such as drying cabinets convert to heat powered products more environmentally friendly electricity will be produced by CHP plants, which can supplant electricity, produced from coal power plants and reduce carbon emissions.
Livscykelanalys av en ekologisk bomullsskjorta - miljöpåverkan från vagga till grav
This study includes a life cycle assessment, LCA, on an ecological produced cotton shirt for the company Reflective Circle, which designs ethical and ecological clothes.Initially were cotton farming and textile production studied to gather basic knowledge about the processes. Since this shirt is being ecological produced in the whole production chain, we studied what an ecological production means, but also how a conventional production works. When this was done we could start to discuss the differences and similarities between the production of the shirt and general conventional production.When the LCA was first initiated, the main focus was on the green house gas emissions from the manure at the cultivation. Thereafter the process steps such as picking, ginning, carding, spinning, weaving and sewing were being studied. The picking is done by hand, but the rest of the processes are handed by machines which consumes energy.
Epiphytic lichen flora in a boreal forest chronosequence
Epifytiska lavar utgör en viktig del av floran i den boreala zonen. Några miljövariabler är kända för att styra artrikedomen och artsammansättningen av epifytiska lavar på beståndsnivå, såsom träddiversitet, beståndsålder, fuktighet och trädens barkstruktur. Skogsbränder utgör den viktigaste störningen i boreala skogar men studier på brandeffekter på epifytiska lavar är mycket få. Detta arbete undersökte artrikedomen, diversiteten och artsammansättningen av epifytiska lavar på basala delar av björkar längs en gradient av 30 skogsbeklädda öar som skiljer sig i storlek och brandhistorik i den norra boreala zonen i Sverige. Målet med studien var att undersöka hur lavfloran påverkades av östorleken och miljövariablerna längs gradienten.