
Sökresultat:
95 Uppsatser om Soxhlet extraction - Sida 2 av 7
Tillvaratagande av GROT i skärgårdsnära miljö :
The main aim of this study was to investigate and compare different methods for the extraction of forest fuel from environments close to an archipelago. The study was based on relevant literature and published reports as well as personal communications.
Forestry has traditionally been characterized by intense efforts to rationalize and mechanize the cutting technique used for timber and pulpwood. In line with the increasing importance of forestry, more concentrated efforts can be expected in the area of techniques and methods, especially for the above-mentioned product lines.
In Sweden, forestry is of major importance and the Swedish economy and standard of living have mainly been created based on the revenues generated from it. Thus, it is vital that Swedish forests are harvested in an efficient and responsible manner.
The demand for biofuel is growing and today accounts for 15% of total Swedish energy production, a share that will probably increase.
This study is based on three research questions, which are described under the heading of Aim. The results reveal that the most profitable method for handling forest fuel is the traditional one, which is also the most commonly used method in southern Sweden, namely the stockpiling of logs in a clearing by means of forwarders followed by splintering at the place from where they will be distributed.
Today, the high cost of barge transport required for the extraction of forest fuel in an archipelago environment renders such operations unprofitable.
Anpassad skötsel - exempel på hyggesfritt skogsbruk i Mellannorrland :
Total protection is often the option chosen when protecting forests with high environmental values. An alternative to total protection is application of management regimes that do not interrupt continuity of tree cover. This study focuses mainly on continuous cover forestry (CCF) in forest stands already protected. All objects are situated in the county of Jämtland in northwest Sweden.
The purpose of the study was to attain a greater knowledge about CCF practices.
Development of a method for determination of pesticide residues in honey using liquid chromatography tandem mass spectrometry
Honey is a product that may contain pesticide residues due to contamination from bees pollinating various plants as well as elimination of vermin inside the hive. Different methods are needed for analysis of pesticides, since the term includes a wide range of different substances. National Food Administration lacks a validated method for determination and quantification of pesticides in honey using liquid chromatography tandem mass spectrometry, LC-MS/MS. The technique is especially important in analysis of polar and non-volatile pesticides, where gas chromatography is not functioning optimally. After investigating what pesticides could be found in honey produced in Sweden, a number of four pesticides suitable for analysis with LC-MS/MS was compiled; boscalid, impidacloprid, tau-fluvalinate and thiacloprid.
Behandling av konfliktbestånd - problem och möjligheter :
Overdue cleanings have for a long time been an important topic of discussion within the forestry sector. When stands that have not been pre-commercially thinned are reaching the level of commercial thinning, many problems occur in terms of decision-making and economical outcomes. These types of stands are commonly known as conflict-stands.
The work was carried out partly as an interview survey towards representatives from the forest sector and the energy sector, partly as a case study of conflict-stands situated in Böksholm, north of Växjö and in Tönnersjö east of Halmstad. The criteria for the studied stands were that they had to be dominated by Norway spruce and be in a severe status of ?conflict?.
The aim of the interview was to get an overview of the situation today, and also analyse trends in terms of conflict stands.
Jämförelse mellan sojaböna och åkerböna som proteinfoder till växande grisar
The soybean can be used in multiple ways, and its high oil content makes it suitable for extraction. Soy bean meal, a by-product of the oil extraction, is a good source of protein with a high feeding value, and is therefore used in a number of different animal feeds. Further, soy bean meal has a low production price, which is one of the reasons for the extensive export of the product. There is a great demand for vegetable-based proteins, especially in the organic production where synthetic amino acids are banned. However, the current production of soy beans is not environmentally sound and that combined with the long transport distances amplifies the need of finding a locally produced protein source.
Smartast vinner : En studie av hur historiens vetenskapliga tankar återkommer i modern pseudovetenskap
A study of how pseudoscience is used in modern science as a method for dividing people into groups depending on their extraction with focus on the book The Bell Curve written by Charles Murray and Richard J. Herrstein..
Interferences during analysis of polyphenols in fruit juices
One of the most commonly used methods for analysis of polyphenols is the Folin-Ciocalteu (FC) method, where the FC reagent has been reported to interfere with some substances in fruit juices. The interfering substance that is present in the highest amount in most fruit juices is ascorbic acid. In this study, the total phenolic content (TPC) of three fruit juices was analysed by the FC method as well as with an enzymatic method with hydrogen peroxide oxidoreductase type II (HRP) for comparison. To investigate how the interfering ascorbic acid affects the TPC, juice samples were analysed after removal and addition, respectively, of ascorbic acid. The samples were analysed with HPLC both before and after the extraction phase of the FC method.
Vad säger bilden?: En utvärdering av återvinningseffektiviteten i ImBrowse
The aim of this master thesis is to evaluate the performance of the content-based image retrieval system ImBrowse from a semantic point of view. Evaluation of retrieval performance is a problem in content-based image retrieval (CBIR). There are many different methods for measuring the performance of content-based image retrieval systems, but no common way for performing the evaluation. The main focus is on image retrieval regarding the extraction of the visual features in the image, from three semantic levels. The thesis tries to elucidate the semantic gap, which is the problem when the systems extraction of the visual features from the image and the user?s interpretation of that same information do not correspond.
Kalvutdragaren - en hjälpande hand? :
The calf extrator?s function has been studied, through measuring traction and how
this varies in different situations, in comparison with corresponding manual
traction situations. This was done against the background that excessive force at
assisted calvings at dystocia can mean life threatening damages on the calf such as
grave acidosis, vertebral fractures, femur fractures and rib fractures. The calf
extractor has earlier been measured to pull with greater force than the established
maximum force of ?two strong men?.
Comparison of real-time PCR assays for screening of meticillin-resistant Staphylococcus aureus
Staphylococcus aureus belongs to the normal flora. Many healthy people are colonized by the bacterium mainly in the nose but also on the skin and on other mucous membranes without showing symptoms. After damage to the skin, the bacterium can enter the wound and cause infections. Methicillin-resistant S. aureus (MRSA) is resistant to b-lactam antibiotics such as penicillin and methicillin.
Mekaniserad ungskogsbehandling för röjning och skörd :
Earlier attempts at mechanising pre-commercial thinning have been met with varying degrees
of success. Most attempts have been based on techniques where residual stems are straddled.
Early treatment is essential to limit damage on residual trees. One part of the present study is an evaluation of mechanised pre-commercial thinning using the new Vimek 404R. Vimek 404R is a fairly small machine that permits selective removal of stems, making it potentially suitable also for areas overdue for pre-commercial thinning. The study established the level of performance for the machine, as well as the improvement needed to make it an economically viable option.
EC-Winder
Have you ever had problems sorting your cables, are the winders you use too big and crude then the EC-winder is the product for you.
The EC-winder concept is a compact and intelligent winder for home application. Its simple design and subtle looks enables it to blend in with the surrounding environment. Its function is designed so that it with ease can be handled by any one after only a couple of instructions. You simply thread the cable trough the opening on the winder and then you rotate the upper part until the cable reaches the desired length. After use the winder can be opened to enable easy extraction of the cable..
Metodutveckling för analys av PBDE och HBCD i sediment
Brominated flame retardants (BFRs) has for many years been used in products to reduce their
flammability, mainly in electronic products, textiles and construction materials.
In 2003, Sweden imported 300 tons of brominated flame retardants.
Leakage of these compounds has polluted natural environments. Fishes has shown increased
contents of these substances, especially fat fish, since brominated flame retardants tends to
accumulate in fatty tissues.
They are also regarded as persistent and that gives them the ability to travel long distances.
What also is really scary is that increased levels of brominated flame retardants have been
detected in human breast milk.
The knowledge of the brominated flame retardants is limited and not so much research has been
done in this field. There are many reasons though, to keep the research going. Partly their
structural resemblance to well-known toxics as PCB, but also their ability to accumulate in
biological systems and enrich in food chains.
In which way they affect humans we really don?t know yet.
Analys och förbättring av en mätenhet för laddning av elfordon
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.
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.