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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
721

Zahlen und Fakten / Numbers and facts

Krämer, Sascha January 2005 (has links)
Vergleiche für: - Größe der Armee - Länder ohne reguläre Streitkräfte - Wehrpflicht - Militärausgaben - Peacekeeping–Missionen - Beteiligung am Irakkrieg - registrierte Schusswaffen in Mittelamerika
722

Thin liquid films with nanoparticles and rod-like ions as models for nanofluidics

Stöckle, Silke January 2010 (has links)
With the rise of nanotechnology in the last decade, nanofluidics has been established as a research field and gained increased interest in science and industry. Natural aqueous nanofluidic systems are very complex, there is often a predominance of liquid interfaces or the fluid contains charged or differently shaped colloids. The effects, promoted by these additives, are far from being completely understood and interesting questions arise with regards to the confinement of such complex fluidic systems. A systematic study of nanofluidic processes requires designing suitable experimental model nano – channels with required characteristics. The present work employed thin liquid films (TLFs) as experimental models. They have proven to be useful experimental tools because of their simple geometry, reproducible preparation, and controllable liquid interfaces. The thickness of the channels can be adjusted easily by the concentration of electrolyte in the film forming solution. This way, channel dimensions from 5 – 100 nm are possible, a high flexibility for an experimental system. TLFs have liquid IFs of different charge and properties and they offer the possibility to confine differently shaped ions and molecules to very small spaces, or to subject them to controlled forces. This makes the foam films a unique “device” available to obtain information about fluidic systems in nanometer dimensions. The main goal of this thesis was to study nanofluidic processes using TLFs as models, or tools, and to subtract information about natural systems plus deepen the understanding on physical chemical conditions. The presented work showed that foam films can be used as experimental models to understand the behavior of liquids in nano – sized confinement. In the first part of the thesis, we studied the process of thinning of thin liquid films stabilized with the non – ionic surfactant n – dodecyl – β – maltoside (β – C₁₂G₂) with primary interest in interfacial diffusion processes during the thinning process dependent on surfactant concentration 64. The surfactant concentration in the film forming solutions was varied at constant electrolyte (NaCl) concentration. The velocity of thinning was analyzed combining previously developed theoretical approaches. Qualitative information about the mobility of the surfactant molecules at the film surfaces was obtained. We found that above a certain limiting surfactant concentration the film surfaces were completely immobile and they behaved as non – deformable, which decelerated the thinning process. This follows the predictions for Reynolds flow of liquid between two non – deformable disks. In the second part of the thesis, we designed a TLF nanofluidic system containing rod – like multivalent ions and compared this system to films containing monovalent ions. We presented first results which recognized for the first time the existence of an additional attractive force in the foam films based on the electrostatic interaction between rod – like ions and oppositely charged surfaces. We may speculate that this is an ion bridging component of the disjoining pressure. The results show that for films prepared in presence of spermidine the transformation of the thicker CF to the thinnest NBF is more probable as films prepared with NaCl at similar conditions of electrostatic interaction. This effect is not a result of specific adsorption of any of the ions at the fluid surfaces and it does not lead to any changes in the equilibrium properties of the CF and NBF. Our hypothesis was proven using the trivalent ion Y3+ which does not show ion bridging. The experimental results are compared to theoretical predictions and a quantitative agreement on the system’s energy gain for the change from CF to NBF could be obtained. In the third part of the work, the behavior of nanoparticles in confinement was investigated with respect to their impact on the fluid flow velocity. The particles altered the flow velocity by an unexpected high amount, so that the resulting changes in the dynamic viscosity could not be explained by a realistic change of the fluid viscosity. Only aggregation, flocculation and plug formation can explain the experimental results. The particle systems in the presented thesis had a great impact on the film interfaces due to the stabilizer molecules present in the bulk solution. Finally, the location of the particles with respect to their lateral and vertical arrangement in the film was studied with advanced reflectivity and scattering methods. Neutron Reflectometry studies were performed to investigate the location of nanoparticles in the TLF perpendicular to the IF. For the first time, we study TLFs using grazing incidence small angle X – ray scattering (GISAXS), which is a technique sensitive to the lateral arrangement of particles in confined volumes. This work provides preliminary data on a lateral ordering of particles in the film. / Mit dem Heranwachsen der Nanotechnologie in den vergangenen zehn Jahren hat sich die Nanofluidik als Forschungsbereich etabliert und erfährt wachsende Aufmerksamkeit in der Wissenschaft, sowie auch in der Industrie. Im biomedizinischen Bereich, wo intrazelluläre Prozesse häufig komplexer, nanofluidischer Natur sind, wird sich vermehrt für ein detailliertes Verständnis von nanofluidischen Prozessen interessiert, z.B. für den Einfluss von Kolloiden verschiedenster Form oder elektrischer Ladung auf die Kanäle und auf das Fließverhalten oder die Auswirkungen der Einengung von Flüssigkeiten und Kolloiden in Nanometer Geometrien. In der vorliegenden Arbeit werden dünne flüssige Filme, hinsichtlich ihrer Funktion als nanofluidische Modelle untersucht. Im ersten Teil der Arbeit wurde die Fließgeschwindigkeit des Fluids aus dem dünnen Film, abhängig von der Konzentration der filmstabilisierenden Tensidmoleküle n – Dodecyl β – D – Maltoside ( β – C₁₂G₂) bei einer konstanten Elektrolytkonzentration von 0.2 mM NaCl untersucht. Mit einem theoretischen Modell konnte das Dünnungsverhalten nachgezeichnet werden. Es wurde eine kritische Tensidkonzentration gefunden, unter der die Oberflächen lateral mobil sind und über der sie sich wie fest verhalten. Dadurch konnten wir Aufschluss darüber erlangen, wie die Oberfläche des Films unter verschiedenen Bedingungen geschaffen ist, und das in Bezug zur Verteilungsdichte der Moleküle an den Oberflächen setzen. Im weiteren wurden komplexere, nanofluidische Systeme untersucht, wobei zum einen ~ 1 nm lange, stäbchenförmige, multivalent geladene Spermidin - Moleküle die punktförmigen Elektrolyte ersetzten. Es konnte eine deutliche Veränderung der Stabilität zwischen Filmen mit und ohne Stäbchen festgestellt werden. Die Filme, mit NaCl, blieben länger in dem metastabilen „Common Film“ (CF) Zustand als die Filme, die eine vergleichbare Konzentration von Spermidin Stäbchen beinhalteten. Die Ergebnisse deuteten auf eine zusätzliche Anziehungskraft durch Brückenbildung zwischen zwei geladenen Oberflächen durch gegensätzlich geladene Stäbchenförmige Moleküle hin. Es konnte gezeigt werden, dass dieser Effekt weder ein Ergebnis von spezifischer Ionenadsorption an die Filmoberfläche war, noch ein Unterschied in den Gleichgewichtszuständen von den Dicken der CFs und der Newton Black Films (NBFs) hervorrief, was auf die korrekte Annahme der Ionenstärke in der Lösung schließen ließ. Auch in Versuchen mit ebenfalls trivalenten Ionen YCl3 wurde festgestellt, dass kein vergleichbarer Überbrückungseffekt auftritt. Die Ergebnisse wurden mit theoretischen Simulationen verglichen und es wurde eine quantitative Übereinstimmung gefunden bezüglich der Größe des Systeminternen Energiegewinns durch den Überbrückungseffekt. Desweiteren wurde das Fließverhalten von Fluiden mit Kolloiden eingeengt in Nanometer Geometrien untersucht. Für zwei verschiedene Arten von Nanopartikeln (Fe3O4 stabilisiert mit Oleinsäure und polymerstabilisierte Goldpartikel) wurde eine Verlangsamung der Fließgeschwindigkeit festgestellt. Mit einem theoretischen Modell konnte das Fließverhalten nur für enorm erhöhte Viskositätswerte des Fluids erklärt werden. Die Viskositätserhöhung wurde mit Partikelaggregaten, die den Ausfluss behindern, erklärt und diskutiert, unter der Annahme eines nicht - Newtonischen Fließverhaltens der Dispersionen. Gleichermaßen wurde die strukturelle Anordnung der Partikel in den Filmen hinsichtlich ihrer vertikalen und lateralen Verteilung untersucht. In dieser Arbeit werden vorläufige Ergebnisse präsentiert, die noch weiteren Studien bedürfen. Mit Neutronenreflexion sollte die Anordnung der Partikel orthogonal zur Oberfläche im Film analysiert werden. Eine qualitative Analyse lässt schließen, dass bei einer höheren Konzentration von Partikeln in Lösung, sich auch eine erhöhte Konzentration von Partikeln im dünnen Film befindet. Leider konnten die Daten nicht hinsichtlich der Lage der Partikel analysiert werden. Zum ersten Mal wurden dünne flüssige Filme mit Kleinwinkelröntgenstreuung unter streifendem Einfall (GISAXS) analysiert. Mit Hilfe dieser Methode sollte eine laterale Anordnung der Partikel im Film untersucht werden. Es konnten erfolgreiche Messungen durchgeführt werden und mit Hilfe der rechnergestützten Analyse konnte eine Aussage gemacht werden, dass ~ 6 nm große Teilchen in ~ 43 nm Abstand sich im Film befinden. Die Aussage bezüglich der kleinen Teilchen könnte sich auf einzelne, kleinere Partikel beziehen, allerdings könnten auch die 43 nm eine relevante Strukturgröße darstellen, da es in der Dispersion gehäuft Aggregate mit dem Durchmesser in dem Größenbereich vorliegen. Zusammenfassend können sich mit dieser Arbeit die dünnen flüssigen Filme als eine wichtige Kernmethode der Untersuchung von nanofluidischen Prozessen, wie sie häufig in der Natur vorkommen, behaupten.
723

Dynamic interactions of interfacial polymers

Plunkett, Mark January 2002 (has links)
The relationship between the amount and conformation of apolymer at the solid-liquid interface, and the resultinginteraction forces between two such surfaces has beeninvestigated. With a degree of control of the polymerconformation, by varying the temperature, solvent quality,polymer charge density etc, it has been possible to measure andinterpret the resulting changes in the surface interactions.The recurring themes of dynamics and hydrodynamics have beencontinually considered due to the large range and viscoelasticnature of the polymeric systems. The polymeric systems investigated in this thesis are, poly(N-isopropylacrylamide), poly (12-hydroxystearate) and a seriesof AM-MAPTAC polyelectrolytes with variable chargedensities. Adsorption and conformation of polymers have beeninvestigated by the novel QCM instrument. By comparison tosimultaneously measured energy loss information, a greaterunderstanding of the conformation of the polymer has beengained, both as a function of layer build-up during initialadsorption, and as a result of induced conformational changes.Comparing the results toin situsurface plasmon resonance and subsequent x-rayphotoelectron spectroscopy measurements, the relativeconcentration of polymer within the layer is determined. Inaddition, efforts have been made to extend the scope of thetechnique, in such ways as measuring with QCM as a function oftemperature and deriving viscoelastic properties. The later isstill to be achieved in absolute terms for polymer layers inliquid environments, yet both the principle and experimentalcapabilities have been shown. Normal interaction forces have been measured as a functionof solvation of the polymer layer, for both adsorbed andgrafted polymer layers. For fully solvated (steric) polymerlayers, which can act as colloidal stabilisers, the dynamics ofthe repulsive force, including hydrodynamics have beeninvestigated. The same has been achieved for collapsed polymerlayers, in which the dynamic adhesion has also beeninvestigated. The effect on the adhesion of three differentdynamic mechanisms has been determined (which, like the surfaceforces, depend on the polymer conformation andviscoelasticity). These dynamic mechanisms are based onbridging forces, polymer entanglement and a viscoelastic‘bulk’response from the surface layers. Lateral or friction measurements have also been completed.The effect of load and rate have been investigated as afunction of both the polymer charge density and the underlyingsubstrate, which result in a variable conformation and bindingstrength to the substrate. This has resulted in a complexaddition of numerous mechanisms, the dominant mechanism beingdetermined by the binding strength to the surface, polymerconformation and viscoelasticity. The results have shown thatadsorbed polymer layers can be used to both increase anddecrease friction, and to change the direction of the ratedependence.
724

En studie av CBRN-funktionen i BG08 och BG11 / A study of CBRN-branch in BG08 and BG11

Schiller, Sara January 2010 (has links)
Syftet med uppsatsen har varit att undersöka vilka skillnader som finns i analysen av CBRN-skyddsförmågan i BG08 och BG11. För att kunna genomföra undersökningen har det varit nödvändigt att beskriva hur EU Battle Group konceptet har tillkommit samt vad konceptet innebär. Följande frågeställningar har legat till grund för studien: Vilka förändringar har gjorts i analysen av CBRN-funktionen i BG08 och BG11? Om det finns några förändringar, hur förklarar man och förstår dessa förändringar? Utifrån de rådande politiska ingångsvärdena för de två styrkorna har viss diskrepans, dock liten, identifierats. Den största skillnaden ligger i vilken nation som skall bidra med förmågan. Den här skillnaden påverkar dock inte nämnvärt de framtagna CBRN-skyddskoncepten. Däremot har det under undersökningens gång framkommit att det hos en del befattningshavare inom Försvarsmakten funnits en önskan om att vidareutveckla CBRN-skyddskonceptet på ett antal punkter till BG11. Då arbetet med BG08 tog form fanns det stöd i HKV att tillgå på strategisk/operativ nivå, vilket saknades under arbetet med BG11. Utifrån den genomförda undersökningen i denna studie framstår detta stöd som relevant för att kunna utveckla det här konceptet på ett adekvat sätt. Författaren har under arbetes gång konstaterat att det torde bli en förändring i den reella förmågan som levererades av Finland till BG08 mot den reella förmåga Norge kommer att besitta i BG11. Det här har inte diskuterats under framtagandet av de två koncepten utan argumentationen har endast baserats på de politiska ingångsvärdena samt hotbilden för EU Battle Group. / The purpose of this paper has been to examine the differences in the analysis of CBRN protection capability of the BG08 and BG11. A secondary purpose to carry out this analysis was to describe the EU Battle Group concept, its development and meaning. The following issues formed the basis for the paper: What changes have been made in the analysis of CBRN branch in BG08 and BG11? If there are any changes, how do we explain and understand these changes? Given the current political input values for the two forces only minor discrepancies could be identified. The main difference is due to the nation responsible for CBRN capacity. This difference, however, does not seriously affect the developed CBRN protection-concepts. However, during the investigation it has emerged that some executives within the Armed Forces desire to develop some points of the CBRN protection-concept in reference to the BG11. When BG08 formed itself there was available support in HKV in strategic/operational level, which was missing in the workflow to BG11. Based on the findings of this paper this support seems relevant to develop the concept adequately. In the course of working on the paper the author has discovered a most likely change in the real capability delivered by Finland to the BG08, and the real ability that Norway will possess in BG11. The development process of the two concepts has not included an analysis of the ultimate ability. Instead is has been based on the input values and political threat for the EU Battle Group.
725

Utrustning för kvinnor : En studie kring Försvarsmaktens anpassning av uniformer och stridsutrustning / Equipment for women : A study about the Swedish armed forces and the adaptation of uniforms and battle equipment

Nilsson, Evelina January 2010 (has links)
I 30 år har kvinnor funnits på militära befattningar i Försvarsmakten. Fram till för fyra år sedan hade nästan inga åtgärder vidtagits för att anpassa den personliga utrustningen till kvinnors behov. Enligt en undersökning från 2005 bidrar detta inte enbart till direkta fysiska begränsningar, utan även till sänkt självförtroende och känslor av kränkning och underordning. Sedan 2006 har Försvarsmakten och FMV arbetat med att ta fram en rad olika persedlar i mindre storlekar, och daglig dräkt har även tagits fram i dammodell. De små storlekarna har visat sig lösa delar av de problem som kvinnor har upplevt. I Försvarsmaktens jämställdhetsplan står det dock bland annat att genus- och jämställdhetsperspektiv ska anläggas vid nyanskaffning av materiel. Det har visat sig finnas ett personligt intresse hos de ansvariga på Högkvarteret och FMV, men det organisatoriska engagemanget i frågan kring utrustning för kvinnor verkar nästan obefintligt. Jag ser dessutom brister i kommunikationen mellan användarna och de som är ansvariga för framtagningen av ny utrustning. Den enda kanalen mellan förbanden och Högkvarteret är s.k. brukarrepresentanter, som ensamma svarar för att föra hundratals människors åsikter uppåt. Enligt teorier kring gruppsammansättningar och minoriteter finns det också anledning att tro att kvinnor, som den minoritet de utgör, riskerar att kvävas av rösterna från majoriteten när denna metod används. Som en lösning på problemet förordar jag ett ökat organisatoriskt engagemang i frågan, genom tydligare stöttning från den högsta ledningen, samt en enkätundersökning, som på bred front samlar in användarnas åsikter om den materiel som tillhandahålls. / Until four years ago no measures had been taken to adapt the personal equipment to women’s needs.This doesn’t only cause direct physical limitations, but also brings out feelings of lowered self-esteem, insult and subordination. Since 2006 the Swedish Armed Forces and FMV (Swedish Defence Materiel Administration) have worked with developing smaller sizes in a number of items of equipment, which also have turned out to solve some of the problems that women have been experiencing. The Swedish Armed Forces’ gender equality plan says that gender and equality perspectives are to be adopted when developing new equipment. Although there has turned out to be a personal interest among the people responsible, the organizational commitment to the issue seems almost non-existant. A lack of communication between the users and the people responsible for the adaptation of equipment for women has also been noted. The only channel between the units and the Headquarters is so called “user representatives”, who are single-handedly responsible for the forwarding of opinions of hundreds of people. There are reasons to believe that women, as a minority, risk being smothered by the voices of the majority when this method is used. As a solution to this problem it is recommended that the organizational commitment is increased, through a more overt support from the higher command, and that a survey is conducted collecting the opinions of a wide group of people about the personal equipment that is supplied by the Armed Forces.
726

A Study of Marketing Strategy in Chinese Software Marketi : A Case Study of UFIDA Softeare Co., Ltd

Zeng, Xiongyu, Du, Yang January 2008 (has links)
Date: 2008-06-08 Program: International Marketing Course: Master thesis in International Marketing (EF0705) Author: Xiongyu Zeng (780925) Yang Du (820830) Tutor: Jan Löwstedt Title: A Study of Marketing Strategy in Chinese Software Market – A Case Study of UFIDA Software Co., Ltd Strategic Question : What should be an Effective Marketing Strategy for UFIDA in order to Increase its Market Shares and Support its Market Leadership Position? Purpose: The purpose of this study is to investigate and analyze the current Chinese financial management software market conditions as well as competitors and to utilize the knowledge from the investigation to consider a better application of marketing mix for UFIDA. Theory and Method: Two theories, five forces and marketing mix, were applied in this thesis. The authors collected primary data by interview and questionnaire to learn company’s marketing operation and feedback of customers on the marketing mix. The authors also collected reliable secondary data with the guideline of five forces framework to learn the marketing situation. The analysis was conducted according to the selected theories and the collected data. Based on the analysis, the authors presented a relevant conclusion. Target Audience: The target audience is the market managers of UFIDA. The researchers wish the result of the paper could bring some benefits for them in the market performance. UFIDA can make use of the research result to design an effective strategy. The authors believe that the research could provide a general guidance and bring benefit to marketers in similar fields and help them to learn competitive situation. Conclusion: From the result of analysis, the authors think the market situation is good for UFIDA. UFIDA has competitive advantages to defend itself against the forces and influence them in its favor. As a consequence, in order to increase market share as well as support its leading position, UFIDA should maintain the existing competitive advantages and improve the disadvantages of marketing operation about marketing mix found from the feedbacks of customer. Through the analysis and recommendation, the authors wish that the investigation result could benefit to UFIDA and bring them some cues for designing an effective marketing strategy.
727

Energy efficiency and ventilation in Swedish industries barriers, simulation and control strategy

Rohdin, Patrik January 2008 (has links)
The energy issue is presently in focus worldwide. This is not only due to increasing environmental concern regarding energy related emissions, but also due to the trend of increasing energy prices. Energy usage in the industrial sector in Sweden today represents about one third of the national energy use. A substantial part of that is related to support processes such as heating, ventilation and cooling systems. These systems are important as they are related both to energy cost and indoor climate management as well as to the health of the occupants. The purpose of this thesis is to reach a more comprehensive view on industrial energy efficiency and indoor environment issues related to industrial ventilation. This has been studied in three themes where the first part addresses barriers to energy efficiency in Swedish industries, the second theme discuss simulation as decision support, and the third studies the variable air volume system in industrial facilities. In the first theme three different studies were made: the first studies non-energy intensive companies in Oskarshamn in Sweden, the second studies the energy intensive foundry industry and the third study was part of an evaluation of a large energy efficiency program called Project Highland. These studies had several findings in common, such as the importance of a strategic view on the energy issue and the presence of a person with real ambition with power over investment decisions related to energy issues at the company. The studies also show that several information related barriers are important for decision makers at the studied companies. This shows that information related barriers are one reason in why energy efficient equipment is not implemented. In the second theme the use of simulation in the form of Computational Fluid Dynamics (CFD) and Building Energy Simulation (BES) are used as decision support for industrial ventilation related studies at two different industries, one foundry is investigated and one dairy. BES has mainly been used to simulate energy and power related parameters while CFD was used to give a detailed description of the indoor and product environment. Together these methods can be used to better evaluate the energy, indoor and product environment and thus enable the implementation of more efficient heating, ventilation and air-conditioning systems. In the third theme the use of Variable Air Volume (VAV) systems was evaluated, and was found to be an efficient way to reduce energy use at the studied sites. At the studied foundry the VAV system is predicted to reduce space heating and electricity use by fans by about 30%, and in the dairy case by about 60% for space heating and 20% for electricity.
728

Prediction Of Non-darcy Flow Effects On Fluid Flow Through Porous Media Based On Field Data

Alp, Ersen - 01 October 2012 (has links) (PDF)
The objective of this dissertation is to investigate the non-Darcy flow effects on field base data by considering gas viscosity, gas deviation factor and gas density as variables. To achieve it, different correlations from the literature and field data have been combined to Sawyer-Brown Method, thus a contribution has been achieved. Production history of selected gas field has been implemented to a numerical simulator. To find out non-Darcy effects quantitatively, Darcy flow conditions have also been run in the simulator for each scenario in addition to non-Darcy flow correlation runs. Extracted data from simulation runs have been analyzed on the basis of Sawyer-Brown Method by introducing several correlations to consider gas viscosity, gas deviation factor and gas density as variables. Engineering and scientific research on non-Darcy flow is still being conducted in order for better understanding the nonlinear flow behavior of fluids through porous media. The deviations from Darcy&rsquo / s Law are attributed to the occurrence of all or alternating combinations of factors that can be categorized as the anisotropy of porosity and permeability, multi-phase flow of fluids in varying phases, magnitude of pressure drop and the subsequent phase change in fluids, and the change in flow regime at elevated rates of flow in porous media. Throughout this dissertation, the factors causing deviations from Darcy flow behavior have been investigated.
729

Towards Increased Energy Efficiency in Swedish Industry : Barriers, Driving Forces & Policies

Thollander, Patrik January 2008 (has links)
Industrial energy efficiency is one of the most important means of reducing the threat of increased global warming. A higheruse of electricity than their European competitors, together with increased energy costs due to increasing energy prices in Swedish industry have negative impacts on results and competitiveness. Of great importance are thus different means which promote energy efficiency such as industrial energy policy instruments. However, cost-effective energy efficiency measuresare not always undertaken. In order to formulate and adopt accurate industrial energy end-use polices, it is thus of importanceto identify the barriers that inhibit the implementation of cost-effective energy efficiency measures. It is also of importance to identify the factors which promote the implementation. The aim of this thesis is to analyze industrial energy systems andmore specifically study factors that promote or inhibit energy end-use efficiency in Swedish industrial companies. Results from this thesis show that the implementation of technical energy efficiency measures is a major means for both energy-intensive and non-energy-intensive Swedish companies to overcome the threat of rising energy prices, for example for electricity. While energy efficiency measures in the non-energy-intensive industry are related mainly to support processes, measures in the studied energy-intensive Swedish foundry industry are related to both support and production processes. In the various case studies of barriers and driving forces, the most significant barriers to energy efficiency - with largevariations for some of the barriers among the studied cases - were found to be: technical risk such as risk of productiondisruptions; lack of time or other priorities; lack of access to capital; cost of production disruption/hassle/inconvenience; other priorities for capital investments; technology considered inappropriate at the site; difficulty/cost of obtaininginformation about the energy use of purchased equipment; and lack of budget funding. The largest driving forces, apart fromcost reductions resulting from lowered energy use, were found to be the existence of a long-term energy strategy and peoplewith real ambition. These driving forces did not, unlike the results of barriers to energy efficiency, vary widely across thestudied sectors. Investment decision support such as optimization has shown to add more information for larger capital-intensive investmentsin energy-intensive industrial SMEs. The thesis also showed that energy audits are an effective means, in terms of publicmoney spent per kWh saved, of providing the industry with information on potential energy efficiency measures. Based on the results presented in this thesis, a policy approach towards non-energy-intensive companies and industrial SMEsshould primarily include providing energy audits free of charge and involve the local authority energy consultants. / Industriell energieffektivisering är ett av de viktigaste sätten att reducera hotet om en globaluppvärmning. En högre relativ elanvändning, i jämförelse med europeiska konkurrenter, tillsammans med stigande energikostnader beroende av stigande energipriser för den svenskaindustrin, riskerar leda till försämrad lönsamhet och försämrad konkurrenskraft. Det är såledesav stor vikt att främja energieffektivisering, exempelvis genom olika typer av styrmedel. Lönsamma energieffektiviseringsåtgärder genomförs emellertid inte alltid, till följd av olikahinder för energieffektivisering. För att kunna formulera precisa styrmedel är det därför avstor vikt att dessa hinder som förhindrar implementering av energieffektiviserande åtgärder,identifieras. Det är också av stor vikt att identifiera drivkrafterna. Syftet med denna avhandling är att analysera industriella energisystem och mera specifikt studera faktorer somfrämjar och förhindrar effektiv slutanvändning av energi i svensk industri. Resultaten visar att hotet om stigande energikostnader, exempelvis beträffande elektricitet,både för icke energiintensiv och för energiintensiv svensk tillverkningsindustri, kan reduceraskraftigt om energieffektiv teknik implementeras. Medan åtgärder i icke energiintensiv industrifrämst är relaterade till stödprocesser så visar sig åtgärderna i den studerade svenska energiintensiva gjuteriindustrin vara relaterade till både stöd- och produktionsprocesser. I fallstudierna beträffande hinder och drivkrafter visade sig de största hindren vara - med storavariationer mellan fallen - tekniska risker såsom risk för produktionsstörningar och avbrott; brist på tid/andra prioriteringar; brist på kapital; kostnader för produktionsstörningar; ickeenergirelaterade investeringar prioriteras högre; tekniken passar ej för företaget;svårigheter/kostnader att erhålla korrekt information beträffande energianvändningen av deninköpta utrustningen; och brist på budgetmedel. De största drivkrafterna var, utöver kostnadsminskningar till följd av minskad energianvändning, förekomsten av en långsiktigenergistrategi och en eldsjäl. Drivkrafterna varierade inte, till skillnad mot hindren, så mycketmellan de olika undersökta fallen. Beslutsstöd såsom exempelvis optimering har visat sig kunna ge ökad information vid störremer kapitalintensiva investeringar i energiintensiva små- och medelstora företag. Vidare har energianalyser visat sig vara ett effektivt sätt, i termer av besparad kWh per statligt insattkrona, att ge industrin information beträffande möjliga energieffektiviserande åtgärder. Resultat från avhandlingen indikerar att ett stöd gentemot icke energiintensiva och små och medelstora företag framförallt bör inkludera statligt finansierade energianalyser med denlokala energirådgivaren som en deltagande aktör.
730

Flow Field and Fibre Fractionation Studies in Hydrocyclones

Bergström, Jonas January 2006 (has links)
Hydrocyclones can be used to fractionate fibres according to their papermaking potential. The obtained fractions typically differ in fibre wall thickness and/or degree of fibre treatment. Despite a multitude of potential application scenarios, the process has so far had little commercial success. This is largely explained by the low fractionation efficiency and unfavourable operating characteristics of the process. The fractionation efficiency of a hydrocyclone is closely related to its flow field. The influence of pulp concentration on the tangential velocity field was therefore studied, by using a self-cleaning pitometer. It was found that the pulp concentration had a strong influence on the tangential velocity. At a feed pulp concentration above 7.5 g/l, the suspension rotated almost as a solid body. As a consequence, the magnitude of radial acceleration and shear stresses decreased dramatically. It is suggested that this is detrimental to the fractionation efficiency. The radial velocity field was measured using an Ultrasonic Velocity Profiler. The measurements showed that the rotational centre of the flow field did not correspond with the geometrical centre of the hydrocyclone. This displacement caused the tangential velocity component of the vortex to contribute substantially to the measurement result of the radial velocity component. Based on the findings in respect to the flow field studies, a novel design for a fibre fractionation hydrocyclone was proposed. The flow field inside this hydrocyclone was compared to that in a conventional hydrocyclone. It was found, that high radial acceleration and shear stresses could be maintained in the novel design even at high fibre concentration. The fractionation efficiency of the novel hydrocyclone was characterised in terms of surface roughness difference between fine and coarse fraction. When operated with refined bleached softwood kraft pulp, the novel hydrocyclone could produce fractions with a substantial surface roughness difference without deteriorating the dewatering characteristics of the fine fraction. A low thickening of the reject is proposed to be the explanation for that. When fractionating TMP, the best efficiency occurred at a concentration of 10 g/l. / QC 20100804

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