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517 Uppsatser om Particle concentration - Sida 11 av 35

Utveckling av en Multi-Zonsmodell för NOx Bildning i Diesel Motorer

This thesis work is the last part of the Master of Science education inmechanical engineering at KTH, Stockholm.The aim of this project was the development of a Multi-zone modelfor NOxformation in Diesel engines. Because of the stringent emissionlegislations, great effort is made to decrease the fuel consumption and theharmful emissions of internal combustion engines. Computer simulationsplay a decisive role in this context because they substitute the expensiveand time-consuming laboratory tests.The model is based on a multi-zone approach and uses the wellknownExtended Zeldovich Mechanism which gives a relation to calculatethe NO formation rate using the concentration of different gas speciesinvolved in the process.All the most important phenomena involved in the Diesel combustionhave been modelled. A special attention is then paid to the equilibriumconcentration calculation; this is a significant part of the model whichstrongly influences the following steps.A Simulink model has also been developed. This second version isbased on the previous model and it is made especially to allow theconnection with other external softwares, GT-power in this case.

Vattenkemin i Fyrisån under snösmältningen

Chemical substances are spread diffusely and uncontrollably as a result of the increased consumption of goods. REVAQ is a certification system that works to reduce the flow of hazardous substances to Swedish treatment plants and to create a sustainable nutrient recycling. According to REVAQ, the yearly accumulating rate of metals should not exceed 0.2% in soil per year. Silver and bismuth are two metals that do not fulfill this requirement. The silver concentration in sludge decreased during the last decade, however the last few years, it has leveled off.

Investigation of yeast Grown in SSF Dring Biothanol Production from Lignocellusosic Material

Ethanol produced from lignocellulosic biomass has the potential to become a promisingalternative to gasoline. In this work the simultaneous saccharification and fermentation (SSF)technology was applied for ethanol production from hardwood with focus on cell growth,ethanol production and contamination.The SSF was performed at PH 5.5 and 35°C for different suspended solid concentrations(8%, 10% and 12%) of pretreated birch slurry which contained 16 % total suspended solids.Two different hexose fermenting yeast strain (Ethanol Red) and pentose fermenting yeaststrain were used.Quantifying the concentration of chemical components and metabolites in the fermentationmedium demonstrated that glucose and xylose are the major fermentable sugars in the slurry.The higher load of slurry (12%) represents a higher content of carbohydrates and potentiallyhigher end concentration of ethanol. Moreover, more lactic acid is produced with the lowerload of slurry (8 % or 10 %), presumably due to a result of a less inhibitory environment forbacterial growth. In this context, acetic acid sticks out as the most important inhibitor withconcentrations of 15.2 and 12.5 and 9.7 g/l respectively in the 12 %, 10 % and 8 % (ofsuspended solids) trials. Using pentose fermenting yeast may lead to higher ethanolproduction, lower xylose uptake and lower lactic acid formation.

Mjölkureahalten som mått på vom-mikrobernas kväveförsörjning och kons miljöbelastning

The aim of this literature study was to analyze how milk urea concentration is working as a measure of the nitrogen supply to rumen microbes and indicator of the environmental load. Questions included in this literature study were how to improve the dairy cattle nitrogen efficiency and what correlations there are between milk urea, nitrogen efficiency and crude protein content in the feed. Effects on the reproduction from high ration protein content are also addressed. Dairy cattle are today fed with large proportions of protein which could lead to high expenditure of feed and environmental pollutions. The nitrogen can be lost to the environment by different pathways; leaching, denitrification or by emission to the air.

Mjölkureahalten som mått på vommikrobernas kväveförsörjning och kons miljöbelastning

The aim of this literature study was to analyze how milk urea concentration is working as a measure of the nitrogen supply to rumen microbes and indicator of the environmental load. Questions included in this literature study were how to improve the dairy cattle nitrogen efficiency and what correlations there are between milk urea, nitrogen efficiency and crude protein content in the feed. Effects on the reproduction from high ration protein content are also addressed. Dairy cattle are today fed with large proportions of protein which could lead to high expenditure of feed and environmental pollutions. The nitrogen can be lost to the environment by different pathways; leaching, denitrification or by emission to the air.

Utvärdering av GnRH-stimulering som en metod att avgöra om en honkatt med okänd historik är kastrerad :

This study has been made to evaluate if there is a significant difference between non-estral intact versus ovariohysterectomized queens in their production of estradiol after exogenous gonadotrophin-releasing hormone stimulation. The purpose is to find a tool, which can help to diagnose if a free-roaming queen is already ovariohysterectomized or not. There are also other situations where this tool could be useful, for example to diagnose the ovarian remnant syndrome. Previous studies in bitches have shown that GnRH-stimulation is an excellent tool to diagnose the presence of ovaries in the bitch. Eleven ovariohysterectomized and eleven intact queens have been included in this study where we have analyzed plasma estradiol and progesterone concentrations before and after a single intramuscular injection of the GnRH agonist buserelin (Receptal?).

Airtours : Slutet för begreppet kollektiv dominerande ställning?

Both the Commission and the Community Courts have on several occasions stated that a concentration that will cause the creation or strengthening of an oligopoly under certain circumstances might cause what?s referred to as a collective dominant position in the market. The concept of collective dominant position has gained a lot of criticism for being poorly defined and thereby create an uncertainty. The Commissions approach when applying the concept has also gained criticism for its lack of consistency. As a consequence of the Court of First Instances (CFI) decision in the case Airtours v.

Geokemin inom osorterade cirklar : Analys av tungmetallers distribution inom jordprofiler tagna från Abiskoområdet, nordvästra Sverige

The Arctic region appears as a pristine remote environment, yet there is increasing evidence that it is greatly impacted by pollution such as lead (Pb) and mercury (Hg). In this environment deposition of Hg has increased threefold since the last industrial revolution. In this study five cryosolic soil profiles within non-sorted circles (NSC) in the Abisko region, northwest of Sweden, has been analyzed to improve our understanding regarding how pollutants are distributed within such type of soil. The soil samples have been analyzed with the use of X-ray fluorescence analysis (XRF), for the measurements of the total concentrations of e.g. lead (Pb) and zirconium (Zr).

Silver och vismut i plaster och färger : Källor till förhöjda halter i slam?

Chemical substances are spread diffusely and uncontrollably as a result of the increased consumption of goods. REVAQ is a certification system that works to reduce the flow of hazardous substances to Swedish treatment plants and to create a sustainable nutrient recycling. According to REVAQ, the yearly accumulating rate of metals should not exceed 0.2% in soil per year. Silver and bismuth are two metals that do not fulfill this requirement. The silver concentration in sludge decreased during the last decade, however the last few years, it has leveled off.

Torrfoder till katt : påverkan och konsekvenser

The cat has evolutionary become an obligate carnivore. Today it is common to feed the cat a dry food. Studies have shown that the dry formula can have negative consequences for the cat. A literature study where conducted to investigate whether the cats origin makes it incapable to compensate for the changes a dry food entails. The impact and implications regarding water intake, energy intake and blood glucose concentration when feeding the cat dry food where examined.

Lärande på hjärnans villkor : En fallstudie av ett antal klasslärares syn på begreppetarbetsminne och arbetsminnesträning

The study's purpose was to get a picture of what a number of class teachers know about and their views on the concept of working memory and working memory training and whether this affects their working and teaching in the classroom. The study is based on qualitative interviews and classroom observations and the theoretical perspectives that the study is based on two: didactic perspective and the socio-cultural perspective. The results of my study show that the class teachers' views and use of the concept of working memory is limited, even if they unknowingly working on parts of it in their teaching. All classroom teachers in my study term difficulties that can arise for students as concentration difficulties, which according to previous research can count towards deficiencies in working memory. All of the respondents in this study believe that it is mostly special education teacher who trains working memory, and that they themselves do not have that knowledge. They also believe that the classroom environment is important for all learning. Common to all respondents consider that the topic is important and would like to have more knowledge of how they can help and support pupils with poor working memory. As a special education teacher and teacher you often meet students who have trouble concentrating, and because of this may be difficult to absorb knowledge as when reading.

Smärtlindring hos killingar efter avhorning :

The main purpose of this study was to investigate the effects of the non steroidal anti-inflammatory drug (NSAID) meloxicam in connection with dehorning of goat kids. Six 2-3,5 weeks old dehorned kids were given daily intramuscular injections of meloxicam (0,5 mg/kg; MG) and five age-matched dehorned kids were given isotonic NaCl (NG) for 3 days. The study was randomized and double blinded. The behavior of the kids was studied one day before dehorning, on the dehorning day and three days after. Blood samples were collected each day before the treatment and analyzed for plasma concentrations of meloxicam, hematocrit, cortisol, progesterone and glucose.

Synoptisk provtagning i vattendrag med eutrofieringsproblem : En studie för att identifiera områden för prioritering av åtgärder

In Halland, agriculture is the major source of eutrophication of water. In the study, synoptic sampling were performed in the three watercourses Nyrebäcken, Skintan and Vinån all located in the county of Halland. Sampling occurred during the period February to May on three occasions with different flow rates: high, low and base flow. Samples were taken in the mainstream and tributaries with intention to show how big the impact of eutrophication it is in the water and  to assess the impact of the tributariesThe results show that all watercourses are affected by eutrophication. Nyrebäcken has the highest concentrations of nitrogen and phosphorus in the mainstream, then Skintan and last Vinån.

Gestaltning av en takträdgård

Gastric ulcer is a common disease among pigs in the whole world where an intensiveproduction occurs. It is mainly the upper region, the nonglandular region of the stomach thatis affected. Gastric ulceration is a disease with several risk factors. The factor that seems tohave the largest impact on the development of gastric ulceration is a small particle size of thefeed. The reported prevalence of gastric ulceration differs from 5 to 100 % and it is a largeherd-to-herd variation.

Improvement of positive strand assay used in detecting positive and negative RNA of hepatitis E virus

Background: Hepatitis E (HEV) is a small, non-enveloped virus that belongs to the viral genus Hepevirus. HEV is a positive sense single-stranded RNA virus and there is insufficient information regarding its replication. This is mainly because the virus has low capacity to grow in normally used cell cultures. Many specific strand assay detection studies have been done in order to understand more about HEV replication. Unfortunately, these assays have the disadvantage of giving false positive results.Aim: The aim of this project was to improve the positive strand assay to increase specificity and eliminate false positivity which is due to high sensitivity of the polymerase chain reaction (PCR).

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