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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

Substitution of amaranth as dye in edge wicking test

Nemez, Emma January 2013 (has links)
Stora Enso, a big Swedish-Finnish forest industry company, wants to find a substitute for the dye that is used in their edge wick analyzes. The dye amaranth, that is used today, is a classified substance that is unhealthy and hazardous. It causes irritation to the eyes, skin and respiratory system. Edge wick is a method to determine the amount of penetrated liquid into the unprotected edges of a packaging board (the surfaces are covered with plastic). It is important to analyze liquid penetration to know that the board will sustain the liquids that it might be exposed to, for example sterilizing liquid (hydrogen peroxide), juice or wine. The dye is used as coloring agent for colorless solutions to enable visual evaluation of the penetration. In the present study several colorants were screened and evaluated in edge wick tests with the standard test liquids used at Stora Enso. Machine, pilot and handmade boards were used in the tests. Surface tension of some test liquids was also determined, as it is important to know if the dyes change the liquid properties since this may influence the penetration. The result of the tests was that a new dye was found, Allura red AC. It has a similar chemical structure to amaranth and seems to act in the same way in different type of test conditions. The recommendation is that amaranth be substituted for allura red AC, since the latter is less hazardous and is not a classified substance.
2

EXPERIMENTAL STUDIES ON A SOLAR POWERED WATER PURIFICATION SYSTEM WITH PHASE CHANGE MATERIAL ENERGY STORAGE

Aydt, Wayne 01 May 2018 (has links)
Accessibility to clean water which is necessary for a healthy lifestyle is a problem that spans the globe. Many societies that lack clean water are also without the energy resources such as electricity or gas that are used for purification. This project is on the development of a solar powered water purification system with Phase Change Material (PCM) energy storage and experimental studies on the system. Water distillation was achieved and analyses were performed on the effects of weather conditions on the distillate production. Solar systems are affected by limited sunshine which occurs only during daylight hours. A second part of the research involved adding a PCM heat exchanger to the system to extend distillation beyond the daylight hours. The analyses evaluated distillate production against outdoor conditions such as temperature, wind speed, and use of the PCM heat exchanger, to determine how they affect the performance of the system. Results show that increased outdoor temperature and clear atmospheric conditions yield greater distillate production. The effects of wind speed were less conclusive. Use of the PCM heat exchanger shifted production to later in the day, but overall, resulted in lower daily production than when the heat exchanger was bypassed. The most definite indicator of distillate production was the temperature differential between the water entering the still and the outdoor temperature.
3

Evaluation of Passive Capillary Wick Samplers for Measuring Deep Infiltration at The Jemez River Basin Critical Zone Observatory

Paras, Ben Krisanto Yap, Paras, Ben Krisanto Yap January 2017 (has links)
Passive capillary wick samplers (PCAPs) are primarily used to sample water from the vadose zone. PCAPs use fiberglass wicks to form a hanging water column that exerts suction on the surrounding soil. Although PCAPs have been used to estimate soil water flux, the accuracy with which PCAPs can estimate flux comes into question due to over/undersampling caused by this applied flux. I used numerical models to explore the effects of a PCAP on flow through the vadose zone. Specifically, I used a two-dimensional axisymmetric flow model of a PCAP embedded in a medium based on HYDRUS. Both steady-state and transient conditions were simulated through the application of various precipitation rates and periods across several soil textures. In this study, I examine soil hydraulic properties, across the soil texture triangle, subject to a range of precipitation events. Results show that the PCAP does over/underestimate water flux. The degree of error is quantified by defining a capture efficiency, which is the ratio of the flux into the plate and the flux that would occur at the same depth with no PCAP present. Higher fluxes and longer time periods resulted in increased convergence of flux into the PCAP, while lower fluxes and shorter durations resulted in divergence of flux from the PCAP. The goal of the study is to understand the behavior of PCAPs under different conditions and to use that knowledge to interpret field measurements in the Jemez River Basin Critical Zone Observatory.
4

Wick Rotation for Quantum Field Theories on Degenerate Moyal Space

Ludwig, Thomas 25 July 2013 (has links) (PDF)
In dieser Arbeit wird die analytische Fortsetzung von Quantenfeldtheorien auf dem nichtkommutativen Euklidischen Moyal-Raum mit kommutativer Zeit zu entsprechenden Moyal-Minkowski Raumzeit (Wick Rotation) erarbeitet. Dabei sind diese Moyal-Räume durch eine konstante Nichtkommutativiät gegeben. Einerseits wird die Wick Rotation im Kontext der algebraischen Quantenfeldtheorie, ausgehend von einer Arbeit von Schlingemann, hergeleitet. Von einem Netz Euklidischer Observablen wird die Lorentz’sche Theorie durch alle Bilder der fortgesetzten Poincare Gruppenwirkung auf der Zeit-Null Schicht erhalten. Dabei wird gezeigt, dass die Vorgänge der nichtkommutativen Deformation und der Wick Rotation kommutieren. Andererseits ist so eine analytische Fortsetzung ebenfalls für Quantenfeldtheorien, die durch einen Satz von Schwingerfunktionen definiert ist, möglich. Durch die Gültigkeit einer Kombination aus Wachstumsbedinungen, die aus der Wick Rotation von Osterwalder und Schrader bekannt sind, kann der Übergang zu einer deformierten Wightman-Theorie gezeigt werden. Abschließend beinhaltet diese Arbeit ergänzende Resultate zu den physikalischen Eigenschaften der Kovarianz und der Lokalität.
5

Settlement Analyses of Grade Supported Tanks Constructed with the Use of Prefabricated Wick Drains and an Earth Preload

Scherer, Rebecca Elizabeth 20 May 2011 (has links)
In the design of tank foundations several design techniques are considered. This study focuses on grade supported tanks constructed under an extensive preload and instrumentation program. Settlement estimation methods were performed and compared to field instrumentation data taken at the project sites. Three project sites were selected for this study. The geotechnical investigations were performed by Eustis Engineering Services, L.L.C. and included both undisturbed soil borings and cone penetrometer tests. Conclusions were made about the accuracy of the calculations and how assumptions affect the settlement computation results.
6

Reduction in Wick Drain Effectiveness in Typical Utah Clays

Smith, Gabriel M. 09 December 2011 (has links) (PDF)
Consolidation theory states that decreasing the spacing of prefabricated vertical drains will decrease the time required to achieve primary consolidation. Previous field tests have shown that there exists a "critical" drain spacing, which is the point at which further spacing decrease does not decrease the time of primary consolidation. This "critical" spacing is thought to be due to disturbance effects from installation of the drains. Previous studies have found that the "critical" drain spacing may be dependent upon soil layering and drain and mandrel dimensions. Thin, interbedded clay layers have been found to be affected greatly due to the smear zone, while few tests have been conducted to determine the validity for thick bedded clays. Currently two design and analysis methods are in existence, neither of which is standardized. The two methods are the modeling of the smear zone, which requires knowledge of soil parameters within that zone, and the modeling using a back-calculated Ch/Cv ratio.In order to evaluate the validity of these design methods and to obtain more data that can be used in determining the relationship between anchor type, drain spacing, and soil profile, full-scale field tests were conducted at Mountain View Corridor in Lehi, Utah. These field tests were performed along a test section that was divided into sections containing 5.8, 5.0, 4.0 and 3.0 ft triangular spacings and rebar or plate anchors. By using the smear zone model, with a Ch/Cv ratio of 1.25 and ds of 3.07 times dm, the time rate of settlement was able to be predicted reasonably well, while using the back-calculated Ch/Cv ratio, with no smear zone, also predicted the time rate reasonably well. From the testing, it was found that the thick clay profile can facilitate closer spacings than a thin clay profile. Also, it was found that the rebar anchor type causes about twice the disturbance of the plate anchor. The results helped validate the existing models and show that the effectiveness of the drains is dependent upon drain spacing, soil profile, and anchor type
7

HEAT AND MASS TRANSPORT INSIDE A CANDLE WICK

Raju, Mandhapati P. January 2007 (has links)
No description available.
8

Effet tunnel dans les systèmes complexes. / Tunnelling in complex systems

Le Deunff, Jérémy 18 May 2011 (has links)
Les travaux présentés dans cette thèse s’inscrivent dans le cadre général de la description de l’effet tunnel dans la limite semi classique h → 0. Nous présentons une nouvelle méthode de calcul direct de la largeur des doublets tunnel. L’expression obtenue est basée sur l’utilisation de traces d’opérateurs quantiques, dont l’opérateur d’évolution Û (T)prolongé analytiquement à l’aide d’un temps complexe T. L’étape suivante consiste en un développement semi classique de ces traces. Nous nous plaçons dans le cadre des systèmes intégrables unidimensionnels afin d’insister sur l’importance d’un temps complexe et on montre que le choix d’un chemin du temps [t] adapté, lors du calcul semi classique des traces, fournit un critère de sélection efficace des trajectoires complexes dominantes. Nous verrons que cette approche retrouve la technique des instantons dans la limite d’un temps purement imaginaire et qu’elle permet d’inclure les descriptions, inaccessibles par une rotation de Wick complète, de l’effet tunnel dynamique et résonant. Nous montrons également comment adapter cette méthode au taux de transmission tunnel d’un état localisé dans un minimum local vers un continuum d’états. Enfin, nous proposerons, en guise de perspectives,d’étudier l’effet tunnel résonant à partir de modèles intégrables présentant des îlots stables entourés de chaînes de tores pour lesquels nous tenterons d’adapter la théorie de l’effet tunnel assisté par les résonances. / The present work is developed within the general framework of the description of the tunneling effect in the semiclassical limit h → 0. We introduce a new method for the direct computation of the tunneling splittings. We get a trace formula involving the evolution operator continued in the complex plane using a complex time T. The next step is to obtain semi classical expansion of these traces. Within the framework of one dimensionnalintegrable systems, we show the key role of a complex time. When performing semiclassical calculations, an appropriate complex-time paths provide an efficient criterion in order toselect the dominant complex trajectories involved in the traces. We will show that our approach includes instanton techniques in the limit of a purely imaginary time and describes dynamical tunneling and resonant tunneling for which a complete Wick is not sufficient.We will show also how our method works for the decay rates. Finally, as a perspective,we will study resonant tunneling from integrable models which exhibit prominent islands surrounded by chains of tori. From these models, we will try to apply the theory of resonant assisted tunneling to integrable systems.
9

Wick Rotation for Quantum Field Theories on Degenerate Moyal Space

Ludwig, Thomas 03 July 2013 (has links)
In dieser Arbeit wird die analytische Fortsetzung von Quantenfeldtheorien auf dem nichtkommutativen Euklidischen Moyal-Raum mit kommutativer Zeit zu entsprechenden Moyal-Minkowski Raumzeit (Wick Rotation) erarbeitet. Dabei sind diese Moyal-Räume durch eine konstante Nichtkommutativiät gegeben. Einerseits wird die Wick Rotation im Kontext der algebraischen Quantenfeldtheorie, ausgehend von einer Arbeit von Schlingemann, hergeleitet. Von einem Netz Euklidischer Observablen wird die Lorentz’sche Theorie durch alle Bilder der fortgesetzten Poincare Gruppenwirkung auf der Zeit-Null Schicht erhalten. Dabei wird gezeigt, dass die Vorgänge der nichtkommutativen Deformation und der Wick Rotation kommutieren. Andererseits ist so eine analytische Fortsetzung ebenfalls für Quantenfeldtheorien, die durch einen Satz von Schwingerfunktionen definiert ist, möglich. Durch die Gültigkeit einer Kombination aus Wachstumsbedinungen, die aus der Wick Rotation von Osterwalder und Schrader bekannt sind, kann der Übergang zu einer deformierten Wightman-Theorie gezeigt werden. Abschließend beinhaltet diese Arbeit ergänzende Resultate zu den physikalischen Eigenschaften der Kovarianz und der Lokalität.
10

Convolution and Localization Operators in Ultradistribution Spaces / Konvolucija i lokalizacijski operatori u ultradistribucionim prostorima

Prangoski Bojan 30 September 2012 (has links)
<p>We investigate the Laplace transform in Komatsu ultradistributions and give conditions under which an analytic function is a Laplace transformation of an ultradistribution. We&nbsp; prove the equivalence of several denitions of convolu-tion of two Roumieu ultradistributions. For that purpose, we consider the _ ten-sor product of _~BfMpg<br />and a locally convex space. We dene specic global symbol classes of Shubin type and study the corresponding pseudodierential operators of innite order that act continuously on the spaces of tempered ultradistributions of Beurling and Roumieu type. For these classes, we develop symbolic calculus. We investigate the connection between the Anti-Wick and Weyl quantization when the symbols belong to these classes. We nd the largest subspace of ultradistri-butions for which the convolution with the gaussian kernel exists. This gives a way to extend the denition of Anti-Wick quantization for symbols that are not necessarily tempered ultradistributions.</p> / <p>Prouqavamo Laplasovu transformaciju u prostorima Komat-suove ultradistribucije i dajemo uslov pod kojim analitiqka funk-cija je Laplasova transformacija ultradistribucije. Dokazujemo ek-vivalentnost nekoliko definicija o konvoluciji dve Rumie ultradis-tribucije. Za &nbsp; ovu svrhu razmatramo &quot; tenzorski proizvod&nbsp; ~ B fMpg i lokalno konveksni prostor. Definiramo specifiqne globalne simbol klase Xubinovog tipa i prouqavamo odgovarajue psevdo diferenci-jalne operatore beskonaqnog reda koji neprekidno deluju na prosto-rima temperiranih ultradistribucija Berlineovog i Rumieovog tipa. Za ove klase gradimo simboliqki&nbsp; kalkulus. Prouqavamo vezu izmeu Anti-Wick-ove i Weyl-ove kvantizacije kad simboli pripadaju ove sim-bol klase. Nalazimo najvei podprostor ultradistribucija za koje konvolucija sa gausovog jezgra postoji. To prua mogunost da pro-xirimo definiciju Anti-Wick kvantizacije za simbole koje nemoraju da su temperirane ultradistribucije.</p>

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