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353 Uppsatser om Chemical precipitation - Sida 18 av 24

Survey of regulations concerning pesticides in Sweden and the EU : cultivation techniques and competition aspects for Swedish onion and apple producer

As a member of the EU, Sweden has, in some cases, transferred the controlling rights to the Union. This means that the rules defined by the EU must be followed in all member countries, including Sweden. The European Agricultural policy constitutes the largest part of the EU's annual budget and is in contrast to many other areas fully funded at EU level. The last decade, many new regulations on chemicals and pesticides have been introduced which brought great changes and a lot of work throughout the Union, including Sweden. Sweden has always had a strict policy on chemicals and has been at the forefront when it comes to sustainable agriculture and environmental management.

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.

Strukturell konservering av måleri på duk Studie kring den långsiktiga stabiliteten hos Plextol D 360, Plexisol P550 och Beva 371

In the early 80s, several new synthetic materials have come to be used in the treatment of canvaspaintings, among them Plextol D 360, Plexisol P 550 and Beva 371. Today, many conservatorsfind the information about the long term sustainability of these binding mediums to beincomplete. Evaluation of synthetic materials is mostly done through clinical research, sometimesartificial aging is simulated. The correlation between artificial and natural aging is however notestablished, useful information can therefore be gained through evaluations of actualconservation treatments. The intention of this study is to find out more about how thementioned products perform over time in normal museum conditions.

Design av försöksanläggning för trycksatt rökgasrening vid oxy-fuelförbränning

Reducing the CO2-pollution, resulting from the combustion of fossil coal for energyproduction, is important to affect environmental changes. One way to achieve a reductionis to use the oxy-fuel technology. The technology uses O2 and re-circulated flue gasduring the combustion which results in a flue gas mainly consisting of CO2. The flue gascould then be compressed and stored without environmental effects. A problem thatfollows from the compression is the risk of acidification in sensitive parts of the process.Acidification can occur because of reactions following from the contact of condensedwater and sulphur- and nitrogen-oxides which are also present in the flue gas.This report compiles and evaluates the basis of a scientific unit with the purpose ofexploring the possibilities of extracting impurities of SOx and NOx from the flue gases.The dimensions of the unit are based on basic conditions, defined for an existing oxy-fuelprocess at Chalmers, and on the results of computer modelling.

Förbättrad planeringspolicy mot lågfrekventa beläggningsprocesser : - I en av Sandviks produktionsenheter

Att ha en god planeringspolicy för samtliga produktionsavsnitt i en produktionsanläggning är en viktig del i en organisation. Inom en industri med många produktvariationer och artiklar är det lämpligt att anpassa flera planeringsmetoder för effektiv planering mot samtliga operationer. I en av Sandviks produktionsenheter för skärtillverkning i Gimo var fokus riktat till att förbättra planeringspolicyn mot lågfrekventa beläggningsprocesser. I denna studie presenterar och optimeras planeringen mot två beläggningstyper vardera inom Physical Vapor Deposition (PVD) och Chemical Vapor Deposition (CVD). I grund för detta examensarbete finns en teoretisk studie, simulering samt fallstudier på Sandvik Coromant AB.

Phosphorus in agricultural soils around the Baltic Sea : comparisons of different laboratory methods as indices for phosphorus leaching to waters

Eutrophication of the Baltic Sea is a serious problem. A major contributing factor is diffuse losses of phosphorus (P) from agricultural land in surrounding countries. In order to estimate P losses, environmental monitoring of small agriculture-dominated catchments is being carried out in most of these countries. Evaluation of the risk of P leaching to waters is usually based on chemical tests originally developed to quantify the amount of soil P available for plant production. The tests are performed in different ways in the different countries and a number of different extraction agents are in use.

Isolating microorganisms from marine and marine-associated samples : a targeted search for novel natural antibiotics

The search for antibiotic compounds from the natural environment has been going on for seven decades, ever since penicillin entered the market and antibiotic treatments became routine. The evolutionary pressure put on the pathogenic microorganisms induced a rapid spreading of naturally occurring resistance genes, leaving only the option of finding new antibiotics to treat the resistant pathogens. Microorganisms have been extensively mined for their biosynthetic abilities to produce biologically active compounds. To date, more than 23 000 microbial natural products have been discovered. The Actinomycetales are ubiquitous bacteria that have been used for antibiotic discovery for more than half a century, and over 10 000 natural products have been identified from the order.

FASTIGHETSPAKETERING : Alltid ett godkänt förfarande?

Chemicals are everywhere in todays society, in humans, animals as well as nature, and they are difficult to avoid. The chemical industry is regarded to be the fastest growing industrial sector, accounting for ten percent of the global economy. A large amount of chemicals are used to produce hygiene products and cosmetics, products that in Sweden only are consumed in quantities of 110 tons per day. Researchers find it increasingly difficult to determine which chemicals that are dangerous and which that are safe, and how they might affect us in the long run. Correlations have been found between chemicals, diseases and other health effects such as cancer, allergies, reproductive and endocrine disorders.

Möjligheter att minska kväveutlakningen genom att anpassa kvävegödslingen till variationer inom stråsädesfält

Due to excess precipitation that cause runoff, all soils in Sweden naturally leaches nitrogen.High leaching from arable land is an environmental problem when the runoff reacheswaters. In the international agreement, Baltic Sea Action Plan, the aim is to reduce therunoff of nutrients. Sweden has agreed to reduce its load of e.g. nitrogen to the Baltic Sea.One of the proposed measures is an increased use of site-specific N-fertilization, which hasbeen shown to increase nitrogen use efficiency and therefore also reduce the nitrogen runoff.Either yields are increased with the same total amount of nitrogen, or the total quantityof nitrogen is reduced with preserved yield levels, which is profitable for the farmers.The dynamics of nitrogen leaching differs between top dressing applications above orbelow the economical optimum. There is a consensus about a difference in the dynamics,but not about its magnitude.

Faror i varor : En studie av unga vuxnas medvetenhet om kemikalier i hygienprodukter och kosmetika

Chemicals are everywhere in todays society, in humans, animals as well as nature, and they are difficult to avoid. The chemical industry is regarded to be the fastest growing industrial sector, accounting for ten percent of the global economy. A large amount of chemicals are used to produce hygiene products and cosmetics, products that in Sweden only are consumed in quantities of 110 tons per day. Researchers find it increasingly difficult to determine which chemicals that are dangerous and which that are safe, and how they might affect us in the long run. Correlations have been found between chemicals, diseases and other health effects such as cancer, allergies, reproductive and endocrine disorders.

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.

Provtagning av trädkärnor för att bedöma föroreningsgraden av klorerade lösningsmedel i grundvatten

Chlorinated aliphatic hydrocarbons (CAH´s) were used widely within dry cleaning facilities and for metal degreasing until their toxicity was discovered. PCE is still used as dry cleaning liquid. Today CAH´s are found in soil environment at places where they have been used in the past. The CAH-concentration in trees growing on contaminated land has quite recently received attention as a cheap and effective way of assessing the extent of a CAH-contamination. The method has however, not been put into use in Sweden.The aim of the study has been to investigate whether the CAH-concentration in tree cores could be used to delineate the spread of CAH in a soil environment under Swedish conditions in different seasons.

Fireball 2 : Energieffektiv fiber produktion

The development within the textile industry is always ongoing with development of new andbetter textiles, which often mean the use of non-natural materials like polyester. This doesn?t lineup with the work shared around the world against an improved environment, so the idea came touse a form of linen fibers instead of polyester as the reinforcing material together with cotton.The idea was to use flax, linen of low quality, which is seen as a waste product and garbage inthe production of high quality linen and flax seed oil. This flax of low quality needs to beseparated before it can be used in cotton spinning machines. Fireball 2 is just that, a process toseparate flax fibers through the treatment of a technique called electrohydraulic discharge.The thesis works goal is to evaluate the Fireball 2 process ability to separate flax fiber.

Fosforavskiljning i reaktiva filter vid småskalig avloppsrening

An excessive input of nutrients to lakes and other water bodies has created a problem with eutrophication in Sweden. Untreated, or partially treated, domestic sewage is a major source for discharge of phosphorus (P), which is the nutrient most frequently responsible for eutrophication of most fresh waters and the Baltic Sea. The waste water can be cleaned by filter materials, which have a high P-retention ability and which after saturation may be used as fertilizers. Four potentially suitable filter materials were tested in batch- and column experiments in this study. In the batch experiments, the following materials were shaken with waste water in time series ranging from 5 seconds to 60 minutes: coarse (1-4 mm) and fine (0-2 mm) Polonite® (heated bedrock from Poland); Filtralite® (light expanded clay aggregates with limestone added before burning); water cooled blast furnace slag (BF-slag) and BF-slag mixed with 10% burned limestone.

Dagvattendammars reningseffekt : påverkande faktorer och metodik för statistisk modellering

Storm water is defined as runoff from precipitation such as rain or snow. It is collected in sewage disposal systems and since it mainly originates from urban areas it can contain high levels of heavy metals, nutrients and oil etc. Polluted storm water is currently treated by different methods such as wet ponds, constructed wetlands and filter strips. This study investigates these methods, which in earlier studies have shown to give varying results regarding their treatment efficiency.This thesis has been written on commission of SWECO VIAK and was aimed at studying those parameters that may affect the treatment efficiency of nutrients and heavy metals in storm water treatment facilities (STF:s). Through literature studies the dominating treatment processes in ponds and wetlands were examined.

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