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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.
1

Analys av miljöanpassad ogräsbekämpning / Analysis of environemntally sustainable weed control

Henningsen, Emelie January 2013 (has links)
Svenska Kraftnät är ett statligt affärsverk vars huvuduppgift är drift och underhåll av det svenska elstamnätet. Bekämpningen av oönskad vegetation är en del i underhållsarbetet i anläggningarna och sker i dagsläget med det kemiska bekämpningsmedlet Roundup. Svenska Kraftnät önskar att minska eller ersätta den kemiska ogräsbekämpningen med en miljöanpassad metod och rapporten syftar till att undersöka den möjligheten.  En av de möjliga metoderna, NCC Spuma, testades i ett fältförsök i en av Svenska Kraftnäts anläggningar och dess miljöpåverkan undersöktes genom en livscykelanalys. NCC Spuma är en termisk metod för ogräsbekämpning som erbjuds av NCC Roads. Ogräset bekämpas med hett vatten och ett isolerande skum. Det isolerande skummet förlänger tiden det heta vattnet skadar ogräset. Skummet bildas då ett extrakt, glucopon 225 DK, blandas med hett vatten. NCC Spuma testades tillsammans med Roundup bio i ett fältförsök för att jämföra metodernas effekt och användarvänligheten. Försöket visade att den största minskningen i ogräs erhölls med NCC Spuma. Men standardavvikelsen var för samtliga resultat hög och för att få en mer exakt jämförelse mellan metoderna behövs mer utförliga försök. Området var torrt till följd av sommarens låga nederbörd vilket ledde till att förekomsten av ogräs var låg. Detta i kombination med att det var stor skillnad mellan mängden ogräs i testrutorna både vid start och under försökets gång bidrog till den stora standardavvikelsen. Framkomligheten vid utläggningen av NCC Spuma i anläggningen var något begränsad och tidsåtgången var stor i jämförelse med den vid besprutningen med Roundup bio. Resultatet från den LCA som utfördes visade att det totala utsläppet för ogräsbekämpning per kvadratmeter motsvarade 119,5 g CO2-ekvivalenter vid utläggning av NCC Spuma. Det största bidraget kom från den diesel som förbrukades vid upphettningen av vattnet, det bidraget motsvarade 85 g/m2. Det nästa största bidraget kom från råvaruproduktionen och var 29 g/m2. Utsläppen från transporter och produktion av extraktet var betydligt mindre. Det som först och främst kan göras är att se till att dagens kemiska ogräsbekämpning är att se till att användningen av Roundup bio sker enligt instruktioner, att dosen anpassas efter mängden ogräs och att det inte används i förebyggande syfte. Att Roundup bio inte kan användas förebyggande beror på att det endast tas upp via växtens blad och inte via dess rötter. NCC Spuma kan vara en alternativ metod för att bekämpa ogräset i stationsanläggningarna, dock finns det utmaningar i framkomlighet och räckvidd som bör lösas innan implementering. Den stora tidsåtgången kan också bli ett problem särskilt i Svenska Kraftnäts större anläggningar. Andra alternativa metoder som Svenska Kraftnät möjligtvis skulle kunna använda är förebyggande åtgärder som samt bekämpning med ättiksyra. I Svenska Kraftnäts riktlinjer för stationsunderhåll anges att ytan ska hållas fri från ogräs, något som i dagsläget sällan uppnås. Ett tröskelvärde för tolererad mängd ogräs skulle kunna förenkla för underhållsentreprenören att avgöra när det finns behov av ogräsbekämpning. / Swedish national grid (Svenska Kraftnät) is a state-owned public utility whose primary responsability is operation and maintenance of the Swedish power grid. Weed management is a part of the maintenance of the facilities of Svenska Kraftnät and today this is done with chemical pesticides. Svenska Kraftnät wishes to replace or reduce the use of chemical pesticides and the aim of this report was to investigate the possibility of doing that.  One of the possible methods, NCC Spuma, was tested in one of the facilities of Svenska Kraftnät. The environmental impact of NCC Spuma was assessed in a Life Cycle Analysis (LCA). NCC Spuma is a thermal method for weed management offered by NCC Roads. The weed control is carried out with hot water and isolating foam. The weed is killed because of the exposure to hot water and the foam prolongs the time the hot water can damage the weed. The foam is formed when an extract, glucopon 225 DK, is added to the hot water.A field experiment was carried out to compare the effects of NCC Spuma and Roundup bio and also evaluate the practical use of NCC Spuma in the facility. The test showed that the use of NCC Spuma resulted in the greatest reduction in weed coverage. However, the standard deviations were very high for all of the results and in order to get a better comparison between the methods more tests are needed. The precipitation during the summer was very low which resulted in low weed growth. This in combination with big variation in weed coverage between the test squares from the start, contributed to the big standard deviation. In order to learn more about the emission of greenhouse gases from NCC Spuma an LCA was carried out. The result showed that the total emission of greenhouse gas for treatment of one square meter one time corresponded to 119,5 g CO2-equivalents. The biggest contribution was from the heating of water because of the use of biodiesel, the contribution was 85 g/m2. The second biggest contribution was from the production of the raw materials to the extract, 29 g/m2. The emissions due to transportation and production of the extract were considerably smaller. To reduce the use of chemical pesticides there are a number of actions Svenska Kraftnät can take. First of all they can make sure that the use of Round up bio is carried out properly according to the instructions, that the dose is adjusted to the weed and that it is only used on surfaces with weed. This since Roundup bio cannot be used to prevent the emergence of new weeds. NCC Spuma could be an alternative to Roundup bio but first the challenges in range due to poles and equipment in the facility should be solved. The time consumption can be a problem especially in the bigger facilities. Other methods that Svenska Kraftnät possibly could use are preventing actions like weed barriers or plants that cover the ground, acetic acid could also be an alternative. In the existing guidelines for the weed management it is said that the surface should kept free from weeds. This is rarely achieved and a target or a threshold value for tolerable amount weed would help the contractor to determine when weed control is necessary.
2

Untersuchungen zur Regulation des Insl3 Gens / Regulation Analysis of the Insl3 Gene

Thamm, Tarvo 29 January 2003 (has links)
No description available.
3

Turbulent Boundary Layer Separation and Control

Lögdberg, Ola January 2008 (has links)
Boundary layer separation is an unwanted phenomenon in most technical applications, as for instance on airplane wings, ground vehicles and in internal flow systems. If separation occurs, it causes loss of lift, higher drag and energy losses. It is thus essential to develop methods to eliminate or delay separation.In the present experimental work streamwise vortices are introduced in turbulent boundary layers to transport higher momentum fluid towards the wall. This enables the boundary layer to stay attached at  larger pressure gradients. First the adverse pressure gradient (APG) separation bubbles that are to be eliminated are studied. It is shown that, independent of pressure gradient, the mean velocity defect profiles are self-similar when the scaling proposed by Zagarola and Smits is applied to the data. Then vortex pairs and arrays of vortices of different initial strength are studied in zero pressure gradient (ZPG). Vane-type vortex generators (VGs) are used to generate counter-rotating vortex pairs, and it is shown that the vortex core trajectories scale with the VG height h and the spanwise spacing of the blades. Also the streamwise evolution of the turbulent quantities scale with h. As the vortices are convected downstream they seem to move towards a equidistant state, where the distance from the vortex centres to the wall is half the spanwise distance between two vortices. Yawing the VGs up to 20° do not change the generated circulation of a VG pair. After the ZPG measurements, the VGs where applied in the APG mentioned above. It is shown that that the circulation needed to eliminate separation is nearly independent of the pressure gradient and that the streamwise position of the VG array relative to the separated region is not critical to the control effect. In a similar APG jet vortex generators (VGJs) are shown to as effective as the passive VGs. The ratio VR of jet velocity and test section inlet velocity is varied and a control effectiveness optimum is found for VR=5. At 40° yaw the VGJs have only lost approximately 20% of the control effect. For pulsed VGJs the pulsing frequency, the duty cycle and VR were varied. It was shown that to achieve maximum control effect the injected mass flow rate should be as large as possible, within an optimal range of jet VRs. For a given injected mass flow rate, the important parameter was shown to be the injection time t1. A non-dimensional injection time is defined as t1+ = t1Ujet/d, where d is the jet orifice diameter. Here, the optimal  t1+ was 100-200. / QC 20100825
4

Adsorption of polyhydroxyl based surfactants

Matsson, Maria January 2005 (has links)
Adsorption on solid surfaces from solution is a fundamental property of a surfactant. It might even be the most important aspect of surfactant behavior, since it influences many applications, such as cleaning, detergency, dispersion, separation, flotation, and lubrication. Consequently, fundamental investigations of surfactant adsorption are relevant to many areas. The main aim of this thesis has been to elucidate the adsorption properties, primarily on the solid/water interface, of a particular class of polyhydroxyl based surfactants: the alkyl glucosides. By the use of ellipsometry, the equilibrium and kinetic aspects of adsorption on titanium dioxide with respect to structural effects has been studied. Furthermore, the effects of small amounts of cationic surfactant additives on the adsorption on silica have been investigated. The results have been compared with similar studies for other nonionic surfactants. We have found that the surfactant structure has a strong effect on the adsorption properties. An increase in the surfactant chain length increases the cooperativity of the system. An increase in the head group polymerization decreases the cooperativity and the plateau adsorbed amount at equilibrium. The effect of surfactant structure on the adsorption kinetics depends on the concentration relative to the cmc, while the there is a decrease in the rate of desorption with increasing hydrophobic chain length independent of the concentration. The adsorption/desorption process is concluded to be diffusion driven, as suggested by the model used. When comparing these results with studies on ethylene oxide based surfactants, we conclude that the two types of surfactants exhibit similar trends on surfaces onto which they adsorb. Adsorption from binary surfactant solutions is even more interesting than adsorption from single surfactant solutions, since it brings us one step closer to the systems used in applications. In addition, adsorption from a mixture can be very different from adsorption from any of the single surfactants in the mixture. Alkyl glucosides alone do not adsorb on silica, but addition of small amounts of a cationic surfactant to the alkyl glucoside solution allows for adsorption on silica. A comparison between the adsorption and bulk properties has shown that mixed micellization explains most, but not all, effects of the coadsorption properties. Changing the pH in the mixed systems reveals that a surfactant with a pH-dependent charge and the ability to adapt its charge to the environment, e.g. a surface, enhances the adsorbed amount over a wider range of pH values than a purely cationic surfactant. It is well known that alkyl glucosides and ethylene oxides adsorb differently on different types of hydrophilic surfaces. As a consequence, replacing ethylene oxides with alkyl glucosides might not be all straight-forward; however, we have shown that the effect of the surface can be eliminated by the use of a cosurfactant. / <p>QC 20101018</p>
5

Nonionic surfactants : A multivariate study

Uppgård, Lise-Lott January 2002 (has links)
In this thesis technical nonionic surfactants are studied using multivariate techniques. The surfactants studied were alkyl ethoxylates (AEOs) and alkyl polyglucosides (APGs). The aquatic toxicity of the surfactants towards two organisms, a shrimp and a rotifer, was examined. The specified effect was lethality, LC50, as indicated by immobilisation. In a comparative study, the LC50 values obtained were used to develop two different types of model. In the log P model the toxicity was correlated to log P alone, while in the multivariate model several physicochemical variables, including log P, were correlated to the toxicity. The multivariate model gave smaller prediction errors than the log P model. Further, the change in reactivity when a surfactant mixture was added to dissolving pulp under alkaline conditions was studied, using the amount of residual cellulose as a measure of the reactivity. Ten AEO/APG mixtures were tested, and the mixture with greatest potential was studied in more detail. An optimum in the amount of added surfactant was found that seems to coincide, according to surface tension measurements, with the CMC.
6

Ärade Theofilos : En narrativ jämförelseanalys av Apg 8:4-15:35 och en inblick i debatten om enheten mellan Luk och Apg

Lindvall, Mattias January 2021 (has links)
I denna uppsats jämförs det interna narrativets utveckling hos Apg 8:4-15:35 i en läsning av ursprungstexten såsom den presenteras i B2000 med det utökade narrativet såsom det presenteras i Codex Bezae (D). Apg 8:4 tar vid efter att Stefanos stenats och vid 15:35 har apostlamötet i Jerusalem ägt rum och Paulus missionsresor börjar.  Genom att göra denna jämförelse går det att se OM och i sådanafall i vilken utsträckning Codex Bezae påverkar förståelsen av det interna narrativet. I denna uppsats undersöks även olika möjligheter i den pågående debatten kring den narrativa enheten hos Lukasevangeliet och Apostlagärningarna. Detta genom att undersöka vilken "sida" i debatten (enhetligt eller ej enhetligt narrativ) som till störst del stödjs av det undersökta narrativet i Apg. De två olika sidorna i debatten representeras av Robert C. Tannehill respektive Richard R. Pervo. Respektive forskares resonemang kring de verser som behandlas inom denna uppsats ställs motvarandra.
7

Adsorption of polyhydroxyl based surfactants

Matsson, Maria January 2005 (has links)
<p>Adsorption on solid surfaces from solution is a fundamental property of a surfactant. It might even be the most important aspect of surfactant behavior, since it influences many applications, such as cleaning, detergency, dispersion, separation, flotation, and lubrication. Consequently, fundamental investigations of surfactant adsorption are relevant to many areas.</p><p>The main aim of this thesis has been to elucidate the adsorption properties, primarily on the solid/water interface, of a particular class of polyhydroxyl based surfactants: the alkyl glucosides. By the use of ellipsometry, the equilibrium and kinetic aspects of adsorption on titanium dioxide with respect to structural effects has been studied. Furthermore, the effects of small amounts of cationic surfactant additives on the adsorption on silica have been investigated. The results have been compared with similar studies for other nonionic surfactants.</p><p>We have found that the surfactant structure has a strong effect on the adsorption properties. An increase in the surfactant chain length increases the cooperativity of the system. An increase in the head group polymerization decreases the cooperativity and the plateau adsorbed amount at equilibrium. The effect of surfactant structure on the adsorption kinetics depends on the concentration relative to the cmc, while the there is a decrease in the rate of desorption with increasing hydrophobic chain length independent of the concentration. The adsorption/desorption process is concluded to be diffusion driven, as suggested by the model used. When comparing these results with studies on ethylene oxide based surfactants, we conclude that the two types of surfactants exhibit similar trends on surfaces onto which they adsorb.</p><p>Adsorption from binary surfactant solutions is even more interesting than adsorption from single surfactant solutions, since it brings us one step closer to the systems used in applications. In addition, adsorption from a mixture can be very different from adsorption from any of the single surfactants in the mixture. Alkyl glucosides alone do not adsorb on silica, but addition of small amounts of a cationic surfactant to the alkyl glucoside solution allows for adsorption on silica. A comparison between the adsorption and bulk properties has shown that mixed micellization explains most, but not all, effects of the coadsorption properties. Changing the pH in the mixed systems reveals that a surfactant with a pH-dependent charge and the ability to adapt its charge to the environment, e.g. a surface, enhances the adsorbed amount over a wider range of pH values than a purely cationic surfactant.</p><p>It is well known that alkyl glucosides and ethylene oxides adsorb differently on different types of hydrophilic surfaces. As a consequence, replacing ethylene oxides with alkyl glucosides might not be all straight-forward; however, we have shown that the effect of the surface can be eliminated by the use of a cosurfactant.</p>
8

Experimental Studies on the Effect of an Upstream Periodic Wake on a Turbulent Separation Bubble

Suneesh, S S January 2016 (has links) (PDF)
The object of the present work is to experimentally study the case of a turbulent boundary layer subjected to an Adverse Pressure Gradient (APG) with separation and reattachment. The effect of unsteadiness on turbulent boundary layer separation by means two different methods were explored viz. the effect of local forcing by acoustic waves and effect of wakes on separation bubble. The experiments were conducted in a low speed open circuit blower type wind tunnel. The turbulent separation bubble was created on the test plate by a contoured ceiling which created the adverse pressure gradient. The velocities were measured using single element hot wire and X-wire. Limited studies on quasi shear stress were also conducted using surface mounted hot film probes. Static pressure was measured using a projection manometer. Boundary layer is tripped near the leading edge of the flat plate to ensure a turbulent boundary layer. Surface pressure distribution and flow visualization were conducted as part of diagnostics. In the case of laminar separation bubble, lot of investigations have been done on the effect of unsteady wake and the most important conclusion was that the wake induces `bypass' transition to turbulence and since the turbulent boundary layer is more resistant to separation, it remains attached. In the case of turbulent separation bubble, laminar-turbulent transition is not relevant and if the bubble is suppressed, it should be by some other mechanism. This is what we seek to unravel in this study. A closer look at the mean velocity profiles reveal the occurrence of inflection point before separation as in the case of laminar separation bubble and the peak values of turbulence intensities correspond to the location of point of inflection. Turbulent separation correlations proposed by various investigators were compared with the present results and are found to be in good agreement. Surface flow visualization pictures are used to get qualitative information. The wall forcing on the separation bubble was done using a speaker which blows a small amount of air when the diaphragm moves up and sucks in when the diaphragm moves down. The blowing effect seems to be more effective in suppressing the separation compared to suction. The interaction with wake is studied using an unsteady bar which is moving up and down. The inflection point in the mean velocity distribution seems to move closer to the wall with the impingement o the wake. Also the turbulence intensities have increased and seem to move closer to the wall. The displacement and momentum thickness have increased and the shape factor has decreased which indicates suppression of the bubble. The quasi shear stress in the separated region also increased which indicates suppression of separation. While the oncoming unsteady wake might be a parcel of fluid with defect velocity when seen in isolation, in comparison to the velocity defect in the separation bubble, it is a region of velocity excess. As a result, one can expect the impingement of the unsteady wake on the TSB to transport momentum thereby contributing to separation reduction. But the mechanism of separation is different from laminar separation bubble affected by wakes. The suppression in the case of turbulent separation bubble is partly due to the entrainment of turbulence and partly due to the kinematic impact of the wake on the bubble.
9

銀行業防制洗錢及打擊資恐機制之實務探討 / A Study on the Practice of Anti-Money Laundering and Counter-Terrorism Financing of Banking Sector

謝雪妮, Hsieh, Hsueh-Ni Unknown Date (has links)
本國為因應2018年亞太防制洗錢組織(APG)相互評鑑事宜,相關單位陸續參照國際規範,如防制洗錢金融行動工作組織(FATF)2012年發布之「防制洗錢及打擊資恐與武器擴散國際標準40項建議」、巴塞爾銀行監理委員會(BCBS)2014年發布之「健全有關防制洗錢及打擊資恐之風險管理」文件等,以及他國作法進行有關防制洗錢及打擊資恐法制規約、監管措施及自律規範等之修正,並促請義務機構強化執行,以期順利通過第三輪相互評鑑。 銀行向為洗錢及資恐犯罪喜好之金流管道,基於銀行提供之金融服務具安全性、便利性及多元化、全球化等優點,不僅吸引一般金融消費者與銀行緊密往來,亦同時受到不良分子之青睞,致金融體系資源易遭不當利用。銀行為金融體系之核心主體,負有防制洗錢及打擊資恐之義務與責任,本文爰就銀行業防制洗錢及打擊資恐實務切入,針對本國銀行應採行之因應措施基本架構進行探討。 本文將先介紹FATF之評鑑流程及方法論,以立下銀行進行防制洗錢及打擊資恐工作之目標,復就達成前開目標為方向,引述金融機構防制洗錢及打擊資恐機制之國際標準,繼而回歸國內外對銀行實際作為之法規要求,試行建構銀行防制洗錢及打擊資恐基本機制,末則就銀行於執行面可改善空間提出重點觀察建議。 隨著工業4.0、Bank3.0及Fintech(金融科技)之快速演進,銀行客戶樣貌及交易型態正在改變,健全防制洗錢及打擊資恐機制是所有銀行業共同面臨之進階版挑戰,本文謹提出銀行機制基本實務報告,俾作為開展細緻化措施之參考。另本文為一般性原則之探討,並非針對特定機構主體之描述,併此敘明。 / For the Mutual Evaluation which will be conducted by the Asia/Pacific Group on Money Laundering (APG) in 2018, basing on the following consulting international norms, such as “International Standards on combating Money Laundering and the Financing of Terrorism & Proliferation (The FATF Recommendations)” published by Financial Action Task Force (FATF) in 2012, “Sound management of risks related to money laundering and financing of terrorism” published by Basel Committee on Banking Supervision (BCBS) in 2014 and foreign advanced practices, the Taiwan authorities have amended the legal system, laws and regulations, supervision measures and self-disciplines referred to Anti-Money Laundering (AML) and Counter-Terrorism Financing(CTF). Meanwhile, every relevant entity is enhancing the prevent measures and internal control on AML/CFT (Counter-Financing of Terrorism) as well. The satisfactory result of the Third Round Mutual Evaluation will be expected. As people know, the banks are always the favorite cash flow channel of money laundering and terrorism financing, since the banks provide the financial services with advantages of safety, convenience, diversification and globalization, etc. Both general financial customers and criminals on ML/FT are attracted to make transactions with the banks. Thus, the financial system’s resources could be utilized improperly. Due to the role of the core of financial system, the banks should take the responsibility and bear the liability of Anti-Money Laundering and combating the financing of terrorism. In this paper, the primary framework on AML/CFT of domestic banks will be outlined according to the real practice. First, this paper has an introduction of mutual evaluation process and methodology in order to set the goal related to AML/CFT of the bank. Next, the model practices of international standards are presenting to achieve the goal for references. Then, this paper will focus on domestic and foreign regulatory requirements on banking, and try to construct the bank’s primary internal system of AML/CFT. Finally, there are some observations of the bank’s performance related to this issue. With the rapid evolution of Industry 4.0, Bank 3.0 and Fintech, the customers’ financial behaviors and transaction types are changing. Therefore, to keep sound internal system of AML/CFT is an advanced challenge to all the banks. This paper is trying to set a primary framework on AML/CFT of domestic banks, and to be taken reference for banks to start developing appropriate prevent measures. In addition, the statement of this paper is an approach to general principles, not indicating any specific institution.

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