We study the buckling of an oil-water interface populated by micron-sized latex particles using a Langmuir trough. We extend pre-existing results to the micron-range with different capillary length and compare the experimental data to the existing theoretical framework. An unexpected trend for the dominant wavelength of buckling is observed, suggesting that there is a transition between regimes in the micron-range. A mechanism for the new regime is proposed. Cascading is reported, as well as novel kinds of transition between wavelengths within the same particle raft. Lastly, the effect of compression on the macroscopic arrangement of particles is investigated, as well as its effect on the buckling wavelength.

Gotland is famous around the world for its unique nature. The agriculture here has always been an important source of income and part of the identity of the island. But today the profession has low status and hard to survive. How can the interest for farming be increased? Gotlandsgården is an investigation about how the agriculture could develop. It strives to re-establish the status of the farmer profession and to become the node for the Gotland's farmers, inhabitants and the tourists.  an investigation about how the agriculture could develop. It strives to re-establish the status of the farmer profession and to become the node for the Gotland's farmers, inhabitants and the tourists. / Gotland är känt för sin fantastiska natur. Lantbruket här har alltid varit en viktig inkomskälla och har alltid varit en viktig del i Gotlands identitet. Idag har inte bondeyrket samma rykte som förr och det är svårt att få tillräckligt med elever till lantbruksskolan i Roma. Hur kan man öka intresset för yrket och Gotlands landsbygd. Det här projektet är en undersökning i hur man genom arkitektoniska tillägg kan skapa en grön nod för Gotlands gröna näringar och lantbruksskola och på det sättet blåsa nytt liv i landsbygden på Gotland.

In this research, a tribocharging model based on the prominent condenser model was used in combination with an Eulerian-Lagrangian CFD model to simulate particle tribocharging in particle-laden flows. The influence of different parameters on particle-wall interactions during particle transport in a particle-laden pipe flow was elucidated. An artificial neural network was developed for predicting particle-wall collision numbers based on a database obtained through CFD simulations. The particle-wall collision number from the CFD model was validated against experimental data in the literature. The tribocharging and CFD models were coupled with the experimental tribocharging data to estimate the contact potential difference of powders, which is a function of contact surfaces' work functions and depends on the physicochemical properties of materials. While the contact potential difference between the particles and wall is an essential parameter in the tribocharging models, the accurate measurement of the property is a complex process requiring a highly controlled environment and special equipment. The results from this research also confirm that particle tribocharging is very much dependant on the particle-wall collision number influenced by various parameters, such as particle size and density, air velocity, and pipe dimensions. Plotting the experimentally measured charge-to-mass ratios against the calculated contact potential differences for samples with different protein contents uncovered a linear trend, which opens a novel approach for protein quantification of powders for a given particle size. Therefore, an algorithm is proposed for rapid quantification of protein content and particle size determination of samples during transport in particle-laden flows based on the triboelectric charge measurement. The algorithm requires a CFD-based artificial neural network to estimate the particle-wall interactions based on the hydrodynamic characteristics of the particles and flow systems. / Thesis / Master of Applied Science (MASc)

Particle ingestion in gas turbine applications can be detrimental to performance and pose significant safety concerns. Areas of high sand concentration are hazardous to aircraft, requiring precautions like routine inspections and maintenance. The engine failure modes are dependent on particle composition, concentration, and size. Particles containing certain minerals tend to melt and stick to turbine blades, which is known as glazing. Alternatively, particles may erode blades from repeated collisions, or they may fill cooling passage holes. Therefore, it is necessary to develop systems that identify these parameters as particles are ingested. This thesis introduces three separate systems responsible for collecting sand concentration, size distribution, and material composition of sand. A particle visualization technique (ParVis), developed at Virginia Tech, was used to validate two sensors developed by commercial partners. One sensor measures particle size and velocity with a method similar to Laser Doppler Velocimetry (LDV). The second sensor measures particle composition with X-Ray Fluorescence (XRF) by physically sampling particles in a flow. There has been little research on applying XRF to moving particles, so experimental data were collected to demonstrate the effectiveness of the sensor. Detection comparisons between two particle types showed promising outcomes for the XRF. Meanwhile, the ParVis technique was iterated to overcome previous limitations and implemented into the testing process to provide particle concentration measurements. Particularly, improvements led to increased accuracy and reliability of the method such as reducing variance in concentration approximations. / Master of Science / Aircraft are constantly ingesting particles into their engines. Those operating in dusty environments are at higher risks of engine failure because more particles are ingested, which cause damage in several ways. As engine manufacturers push the turbine operating temperatures higher for efficiency and emissions, sand particles reach melting temperatures and stick to turbine blades, which results in overheating. Because of the potential risks to life, sand ingestion research continues to provide solutions for improving aircraft safety. This study explores the capabilities of new sensors to quantify characteristics of ingested particles, including the concentration, size distribution, and material composition of sand. An illumination technique for measuring sand concentration from particle imaging was developed at Virginia Tech. The technique was iterated to overcome previous limitations and improve its reliability during this study. It provides a more accurate depiction of the testing conditions that can be used to diagnose and calibrate sensors. In this case, two sensors issued by Creare were tested, one of which measures size and particle velocity, while the other measures sand composition. The first sensor relies on non-intrusive optical measurements and can be mounted directly to an engine inlet. The second sensor collects particles from the inlet flow and applies X-Ray Fluorescence (XRF) to the moving particles. There has been little research on applying XRF to a flow of particles, so experimental data were critical to demonstrate the effectiveness of the sensor. technique was iterated to overcome previous limitations and implemented into the testing process to provide particle concentration measurements.

Neben der Verringerung von Verkehrsunfällen und Staus ist ein wichtiges Ziel der Verkehrspsychologie, die Luftverschmutzung durch den Verkehr zu reduzieren. Elektrofahrzeuge (BEVs) könnten die CO2-Emissionen deutlich reduzieren. Der weltweite BEV-Bestand nimmt zwar stetig zu, aber die Marktanteile in den meisten EU-Ländern lag 2016 dennoch nur bei rund 1% (International Energy Agency, 2016). Eine weitreichende Verbreitung von Elektrofahrzeugen birgt nicht nur Vorteile in sich, sondern kann auch zur Belastung der Stromnetze führen. ‚Intelligente Ladesysteme‘, die den Ladeprozess an die Netzbelastung und Nutzeranforderungen (z.B. Ladestand bei Abfahrtszeit) anpassen, gelten als vielversprechende Lösung. Vor dem Hintergrund der bisher geringen Verbreitung von Elektrofahrzeugen und der mit einem Erfolg der Elektromobilität steigenden Relevanz intelligenter Ladesysteme entsteht die Notwendigkeit psychologische Faktoren zu identifizieren, die die Evaluation und Akzeptanz von Komponenten des Elektromobilitätssystems beeinflussen. An dieser Stelle knüpft die vorliegende Dissertation an. Der (praktische) Erfahrungshorizont vieler Menschen in Bezug auf Elektrofahrzeuge und intelligente Ladesysteme ist sehr limitiert. Unerfahrene Nutzer solch neuer Systeme begegnen bisher unbekannten Herausforderungen in der Mensch-Maschine-Interaktion. Beispielsweise geht das elektrische Fahren, im Vergleich zum Fahren herkömmlicher Fahrzeuge, mit einer wesentlich niedrigeren Reichweite, einer geringeren Geräuschkulisse, neuen „Nachtankprozessen“ und Fahrfunktionen wie der Rekuperation (d.h. regeneratives Bremsen bei dem kinetische in elektrische Energie umgewandelt wird) einher. Dieses Thema wird ebenfalls in der vorliegenden Dissertation aufgegriffen. Das erste Forschungsziel fokussierte die allgemeine Bewertung und Akzeptanz von Elektrofahrzeugen sowie den Einfluss von praktischer Erfahrung. Im Rahmen einer Feldstudie mit zwei 6-monatigen Studienphasen (Artikel II), einer Onlinestudie (Studie I von Artikel III) sowie einer 24-Stunden Testfahrt (Studie II von Artikel III) wurde dieses Ziel untersucht. Für die verschiedenen Arten von Erfahrung (langzeitig mit gleichem Fahrzeug vs. unkontrolliert vs. kurzzeitig mit gleichem Fahrzeug) zeigten sich unterschiedliche Effekte auf die Akzeptanz von Elektrofahrzeugen, die detailliert diskutiert werden. Die Berichte der Feldstudienteilnehmer (langzeitige Erfahrung) zu Vor- und Nachteilen von Elektrofahrzeugen zeigten, dass sich die Salienz bestimmter Vor- und Nachteile über die Nutzungszeit hinweg ändert. Vor allem die Vorteile, die beim Alltagstest direkt erlebt werden können (z.B. das angenehme Fahrgefühl, die geringe Geräuschkulisse), waren in ihrer Salienz gestiegen. Es gibt erlebbare Barrieren, wie die Ladedauer, die innerhalb der Feldstudie an Prägnanz verloren, aber auch andere, wie die Reichweite, die in ihrer Bedeutsamkeit konstant blieben. Die Vorher-Nachher-Studien (Artikel II & Studie II von Artikel III) zeigten, dass die Erwartungen der Tester an solch ein Fahrzeug im Alltagstest insgesamt erfüllt werden und die Einstellung gegenüber Elektrofahrzeugen positiv bleibt. Im Rahmen der 24-Stunden-Testfahrt (kurzzeitige Erfahrung) zeigte sich zudem ein Anstieg in der Zufriedenheit mit Elektrofahrzeugen. Dem gegenüber stehen die geringen Kaufabsichten der Befragten. Der Alltagstest mit einem Elektrofahrzeug, egal ob kurz- oder langzeitig, zeigte keine Effekte auf die Kaufintention. Allerdings wiesen die Ergebnisse der Onlinebefragung darauf hin, dass Personen, die bereits ein Elektrofahrzeug gefahren sind, gegenüber dem Kauf eines Elektrofahrzeugs nicht so stark abgeneigt sind wie Unerfahrene, aber dennoch keine klare Intention zeigen. Das zweite Forschungsziel bestand in der Untersuchung wie praktische Erfahrung mit dem Nutzerverhalten und der Evaluation bezüglich der Elektrofahrzeugcharakteristika zusammenspielt. Am Beispiel der Rekuperation wurde untersucht wie sich die Menschen im Rahmen einer 6-monatigen Feldstudie an solch eine Funktion gewöhnen, ihre Nutzung erlernen und ob sich dies in der Bewertung der Funktion widerspiegelt (Artikel I). Die Ergebnisse aus den Fahrzeugdaten weisen darauf hin, dass die Adaption an diese Funktion recht zügig abgeschlossen ist und dem Power Law of Practice (Newell & Rosenbloom, 1981) folgt. Die Rekuperationsfunktion wird durch die Nutzer positiv bewertet und die Zufriedenheit mit der Rekuperation steigt mit der Nutzungszeit. In zwei weiteren Studien wurde die Bewertung von Elektrofahrzeugcharakteristika zwischen Elektrofahrzeug-Erfahrenen und –Unerfahrenen verglichen. In der Onlinestudie (Studie I in Artikel III) mit dem unkontrollierten Erfahrungsfaktor zeigten sich kaum Unterschiede. Lediglich ‚Reichweite und Laden‘ bewerteten die Erfahrenen positiver. Kontrollierte, kurzfristige Erfahrung (Studie II in Artikel III) führte zu einer positiveren Bewertung von Beschleunigung und Fahrspaß, Geräuschlosigkeit, Sicherheit und Reliabilität, Umweltfreundlichkeit sowie des Rufs von Elektrofahrzeugen. Die Bewertung von Reichweite und Laden blieb unverändert. Das dritte, übergeordnete Ziel dieser Dissertation bestand darin, akzeptanzbeeinflussende Faktoren zu identifizieren, die als Ansatzpunkte für zukünftige Weiterentwicklungen und Strategien zur Erhöhung der Akzeptanz genutzt werden können. Dazu wurde das Potential der Bewertung verschiedener Elektrofahrzeugattribute, der Faktoren der Theorie des geplanten Verhaltens (Ajzen, 1991) sowie der Erfahrung mit Elektrofahrzeugen zur Vorhersage der Akzeptanz im Rahmen der beiden Studien in Artikel III untersucht. Der soziale Faktor (subjektive Norm) und die Bewertung von ‚Reichweite und Laden‘ wirkten sich am stärksten auf die Vorhersage von Einstellungs- und Verhaltensakzeptanz aus. In der Onlinestudie mit between-subjekt Design, zeigte sich zudem ein starker Erfahrungseffekt auf die Kaufabsicht. Zudem erwies sich auch der Faktor ‚Beschleunigung und Fahrspaß‘ als relevante Größe für die Akzeptanz. Vor dem Hintergrund der aktuellen Entwicklungen, im Detail den sinkenden Batteriekosten und damit günstiger werdenden Reichweiteressourcen, eröffnen die Ergebnisse Ansatzpunkte, um die Akzeptanz zu steigern. Die Bewertung der Performanz und das angenehme Fahrgefühl beim elektrischen Fragen weisen einen nicht zu vernachlässigbaren Einfluss auf die Akzeptanz von Elektrofahrzeugen auf und konnten durch ein kurzzeitiges Erfahrungserlebnis positiv beeinflusst werden. Das letzte Forschungsziel dieser Dissertation fokussierte das intelligente Laden. Die Ergebnisse der 5-monatigen Feldstudie (Artikel IV) zeigten, dass ein intelligentes Ladesystem (mit aktiver Nutzerbeteiligung) nutzbar und akzeptabel ist. Allerdings zeigten die Ergebnisse auch, dass eine positive Kosten-Nutzen-Bilanz für die Nutzer von hoher Relevanz ist. Der zusätzliche Aufwand beim Laden erwies sich als signifikant höher und die finanziellen Anreize durch die Nutzung des Systems als niedriger als erwartet. Zudem fühlten sich die Nutzer durch das System zusätzlich in ihrer Mobilität eingeschränkt. Demnach sollten zukünftige, intelligente Ladesysteme sorgfältig gestaltet werden, so dass der Aufwand und die Reduzierung von Flexibilität und Mobilität nicht so hoch sind, dass die Barriere "Reichweite und Laden" für die Akzeptanz von Elektrofahrzeugen erhöht wird. Basierend auf den Ergebnissen wurden verschiedene Implikationen abgeleitet. Die Weiterentwicklung des Elektromobilitätssystems sollte sich darauf konzentrieren, die Barrieren bezüglich Reichweite und Laden zu reduzieren sowie die positiven Aspekte des elektrischen Fahrens zu vermitteln. Zudem sollten zukünftige Akzeptanzmodelle, vor allem für bisher eher unbekannte Objekte oder Technologien, einen Erfahrungsfaktor und die Bewertung verschiedener, objekt-/technologie-spezifischer Attribute enthalten, da dadurch wichtige Aspekte zur Verbesserung des Forschungsobjektes identifiziert werden können. Die Ergebnisse zeigten außerdem, dass der soziale Einfluss in zukünftigen Strategien zur Akzeptanzförderung von Elektrofahrzeugen adressiert werden sollte und eine Testfahrt mit einem Elektrofahrzeug, das dem aktuellen Entwicklungsstand entspricht, ein strategisches Werkzeug zur Akzeptanzsteigerung darstellt.

This thesis presents the study of laminar to turbulent transition of particle laden flows. When a flow becomes turbulent, the drag increases one order of magnitude compared to a laminar flow, therefore, much research is devoted to understand and influence the transition. Previous research at the Linne Flow Centre at KTH has concentrated on the understanding of the bypass transition process of single-phase fluids. Though there are still questions, the principles of this process are now, more or less, known. However, little is known of the influence of particles on transition. While experiments in the 1960s already showed that particles can reduce the friction in turbulent channel flows significantly. The question explored in this thesis is whether this can be attributed to their influence on transition. The initial onset of transition has been investigated with both modal and non-modal linear stability analysis in a Poiseuille flow between two parallel plates. Particles are introduced as a second fluid and they are considered to be solid, spherical and homogeneously distributed. When the fluid density is much smaller than the particle density, ξ (≡ ρf/ρp) &lt;&lt; 1, an increase of the critical Reynolds number is observed. However, transient growth of streamwise vortices resulting in streaks is not affected by inclusion of particles. Particles with ξ ∼ 1 hardly seem to have an effect on stability. Although linear analysis shows that particles hardly influence the transient growth of disturbances, they might affect other (non-linear) stages of transition. To investigate such effects, the full Navier-Stokes equations for 3D Poiseuille flow between two parallel plates are numerically solved and particles are introduced as points with two-way coupling. For particles in a channel flow with ξ&lt;&lt;1, results show that the transition to turbulence is delayed for mass fractions ƒ (=mp N / ρf) larger than 0.1. For a mass fraction of ƒ=0.4 the initial disturbance energy needed to get a turbulent flow increases with a factor of four. Even if lower particle mass fractions ƒ are used, locally there could be large particle mass fractions. Therefore, the next step is to investigate the generation of local large particle mass fractions ƒ. Such particle clusters can be as large as the typical flow structures in the flow, like streak width and vortex size. Then they might change the flow field and (in)stability mechanisms. Numerical simulations of bypass transition in a boundary layer flow are used to determine whether particles cluster and where they tend to cluster. It is found that point particles with ξ&lt;&lt;1 and a large particle relaxation time tend to move in the low speed regions of the flow. In case of streaks, the low speed streaks are most favourable. For smaller particle relaxation times, particles act as tracers and do not have a preferential position and are homogeneously distributed. For particles with ξ∼1 the linear stability analysis showed no transition effect at any ƒ. However, one effect neglected until now is that of particle size. For particles with dimensions of the same order of magnitude of the flow disturbance, particles might influence the flow field. To investigate whether such particles migrate towards positions where they can affect transition some exploratory numerical simulations and experiments are performed. Numerically, the lateral migration of large particles (H/d=5) with ξ=1 in a 3D Poiseuille flow between two parallel plates is investigated. In laminar channel flow, large particles tend to move laterally due to shear to an equilibrium position. For a single large particle some key parameters for migration are identified: the size of the particle and the velocity of the fluid. When multiple particles are present, they tend to form particle trains. If particles are close, they influence each other and the equilibrium position shifts towards the wall, where the final position is dependent on the inter particle spacing. Also, not one steady equilibrium position is present, but particles move around an equilibrium position. Experimentally, migration of particles in bypass transition with ξ=1 is investigated to find out whether neutrally buoyant particles have a preferential position within streaks. The first results with tracer particles (d∼50μm) and few large particles (d∼200μm) do not show detectable preferential positioning. / <p>QC 20131030</p>

In single phase, steady, turbulent axisymmetric jets, the time-averaged velocity field can be characterised by the decay in centreline velocity and increased spread with increasing distance from the jet orifice. In a two-phase or ‘particle-laden’ jet, the particles will modulate the jet turbulence and exchange momentum with the gas phase. Consequently, these effects reduce both the centreline velocity decay and spreading rates with respect to the single-phase jet. Empirical exponential scaling factors were found by previous authors to describe the reduced centreline decay and spreading rates well for low Stokes numbers. In this thesis, power-law scaling factors are found to scale well a wide range of centreline velocity decay and spreading rate data published over the past 40 years, for a wide range of Stokes numbers. The power-law scaling is composed of three different regimes. For low Stokes numbers St₀ ≲20, it is found that the gas phase centreline velocity, u₀/uc collapses if plotted as a function of x/D(1 + Ø₀)⁻¹, and the velocity profile half widths r₁/ ₂ collapse if plotted as a function of x/D(1+Ø₀)⁻¹. Here, u₀ is the exit velocity, Ø₀ is the exit mass loading, x is the axial coordinate and D is the pipe diameter. For intermediate Stokes numbers, u₀/uc collapses if plotted as a function of x/D(1 + Ø₀)⁻¹ and r₁/ ₂ collapses if plotted as a function of x/D(1 + Ø₀)⁻¹/². For high Stokes numbers St₀ ≳ 200, u₀/uc collapses if plotted as a function of x/D(1 + Ø₀)⁻¹/² and the half width is approximately independent of Ø₀. In addition to the velocity of the gas phase, other aspects of particle- laden jets are found to be amenable to scaling by power-law functions. It is found that reported solid phase mass flux data scales similarly to gas phase measurements. Limited solid phase concentration and entrainment measurements reported in the literature are also found to scale by power-law functions. Whereas that limited data was obtained from the literature, measurements of the distribution of particles in particle-laden jets were conducted to further assess the validity of the scaling regimes to the solid phase. A planar light scattering technique is conducted to measure the distribution of particles in an axisymmetric jet and their subsequent scaling (or lack thereof) are reported for a variation in Ø₀, Stokes number and gas phase jet exit density. For Stokes numbers based on the pipe friction velocity St* ₀ ∼ 1, half widths of particle distributions were found to scale with x/D(1+Ø₀)⁻¹/² . The apparent centreline concentration was found to be independent of Ø₀ at this same St* ₀ . For Stokes numbers based on the pipe friction velocity St*₀ < 1, half widths are independent of Ø₀. The effect of the other parameters, i.e. Stokes number and density ratio, on centreline distributions and half widths are also investigated. Measurements of particle distributions, delivered via an annular channel, in a triangular oscillating jet (OJ) flow are also reported for a variation in momentum ratio, the ratio of OJ momentum to channel momentum and mass loading. The results of the variation in momentum ratio on particle distributions are compared with an existing precessing jet (PJ) study. It is the aim of this study to determine the experimental conditions for which the OJ nozzle is superior to the PJ nozzle. The use of an OJ nozzle is preferable at an industrial scale by virtue of its lower driving pressure compared with a PJ nozzle. It is found that particle distributions in a PJ flow spread at a greater rate with increasing momentum ratio compared with the spread of particles in an OJ flow. However, at momentum ratios approximately less than unity, the absolute spread from an OJ is greater. This also corresponds to nozzle driving pressure less than approximately 10kPA. For an increase in mass loading, the spread of particle distribution in the OJ decreases and recirculation increases. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1337352 / Thesis (M.Eng.Sc.) -- University of Adelaide, School of Mechanical Engineering, 2008

In single phase, steady, turbulent axisymmetric jets, the time-averaged velocity field can be characterised by the decay in centreline velocity and increased spread with increasing distance from the jet orifice. In a two-phase or ‘particle-laden’ jet, the particles will modulate the jet turbulence and exchange momentum with the gas phase. Consequently, these effects reduce both the centreline velocity decay and spreading rates with respect to the single-phase jet. Empirical exponential scaling factors were found by previous authors to describe the reduced centreline decay and spreading rates well for low Stokes numbers. In this thesis, power-law scaling factors are found to scale well a wide range of centreline velocity decay and spreading rate data published over the past 40 years, for a wide range of Stokes numbers. The power-law scaling is composed of three different regimes. For low Stokes numbers St₀ ≲20, it is found that the gas phase centreline velocity, u₀/uc collapses if plotted as a function of x/D(1 + Ø₀)⁻¹, and the velocity profile half widths r₁/ ₂ collapse if plotted as a function of x/D(1+Ø₀)⁻¹. Here, u₀ is the exit velocity, Ø₀ is the exit mass loading, x is the axial coordinate and D is the pipe diameter. For intermediate Stokes numbers, u₀/uc collapses if plotted as a function of x/D(1 + Ø₀)⁻¹ and r₁/ ₂ collapses if plotted as a function of x/D(1 + Ø₀)⁻¹/². For high Stokes numbers St₀ ≳ 200, u₀/uc collapses if plotted as a function of x/D(1 + Ø₀)⁻¹/² and the half width is approximately independent of Ø₀. In addition to the velocity of the gas phase, other aspects of particle- laden jets are found to be amenable to scaling by power-law functions. It is found that reported solid phase mass flux data scales similarly to gas phase measurements. Limited solid phase concentration and entrainment measurements reported in the literature are also found to scale by power-law functions. Whereas that limited data was obtained from the literature, measurements of the distribution of particles in particle-laden jets were conducted to further assess the validity of the scaling regimes to the solid phase. A planar light scattering technique is conducted to measure the distribution of particles in an axisymmetric jet and their subsequent scaling (or lack thereof) are reported for a variation in Ø₀, Stokes number and gas phase jet exit density. For Stokes numbers based on the pipe friction velocity St* ₀ ∼ 1, half widths of particle distributions were found to scale with x/D(1+Ø₀)⁻¹/² . The apparent centreline concentration was found to be independent of Ø₀ at this same St* ₀ . For Stokes numbers based on the pipe friction velocity St*₀ < 1, half widths are independent of Ø₀. The effect of the other parameters, i.e. Stokes number and density ratio, on centreline distributions and half widths are also investigated. Measurements of particle distributions, delivered via an annular channel, in a triangular oscillating jet (OJ) flow are also reported for a variation in momentum ratio, the ratio of OJ momentum to channel momentum and mass loading. The results of the variation in momentum ratio on particle distributions are compared with an existing precessing jet (PJ) study. It is the aim of this study to determine the experimental conditions for which the OJ nozzle is superior to the PJ nozzle. The use of an OJ nozzle is preferable at an industrial scale by virtue of its lower driving pressure compared with a PJ nozzle. It is found that particle distributions in a PJ flow spread at a greater rate with increasing momentum ratio compared with the spread of particles in an OJ flow. However, at momentum ratios approximately less than unity, the absolute spread from an OJ is greater. This also corresponds to nozzle driving pressure less than approximately 10kPA. For an increase in mass loading, the spread of particle distribution in the OJ decreases and recirculation increases. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1337352 / Thesis (M.Eng.Sc.) -- University of Adelaide, School of Mechanical Engineering, 2008

The term “Fundamentalism” used as a comparative category within the academic study of religion has become problematic. Fundamentalism, is not one comprehensive movement but is, in fact, a phenomenon which encompasses a variety of beliefs, practices, and expectations. This thesis will explore the diversity of several different and distinct fundamentalist movements. I will discuss the natures of four Christian movements that have been labeled “fundamentalist” – Jehovah’s Witnesses, Christian Reconstructionists, Jerry Falwell and Pat Robertson – on several key points, eschatology, political philosophy, as well as level of social involvement. I will then turn to fundamentalism as it is used as a category to describe a global phenomenon. I will discuss three different scholarly approaches by turning to the work of Bruce Lawrence, Mark Juergensmeyer, and Bruce Lincoln on the Islamic “fundamentalist” group al- Qaeda. Finally I will argue that the category “fundamentalism” can be best understood in terms of a family resemblance.

This thesis reports an experimental investigation of low Reynolds number particle-laden turbulent flows in a horizontal plane channel. Experiments were conducted over a smooth wall and over two rough surfaces made from sand grain and gravel of relative roughness k/h ≈ 0.08 and 0.25, respectively, where k is the roughness height and h is the channel half-height. The flow was loaded with small solid particles with diameters less than 1/10 of the length scale of the energy-containing eddies, and whose concentrations decreased with time due to sedimentation. A novel particle image velocimetry (PIV) method that employed colour filtering for phase discrimination was used to measure the velocities of the fluid and solid particles. Over the smooth wall, the particles mean velocity, turbulence intensities and Reynolds shear stress matched those of the unladen flow very well. There were substantial differences between particle and fluid profiles over the rough wall, which include more rapid reduction in the particle mean velocity and significantly larger turbulence intensities and Reynolds shear stress compared to the unladen flow values. Stratification of the particle concentration led to attenuation of the fluid wall-normal turbulence intensity. This effect was nullified by the roughness perturbation leading to collapse of the wall-normal turbulence intensities over the rough wall. The streamwise turbulence intensity also collapsed over the rough wall but it was found that particles augmented the fluid Reynolds shear stress due to enhanced correlation between the rough wall streamwise and wall-normal velocity fluctuations. A quadrant decomposition of the fluid Reynolds shear stress also revealed corresponding enhancements in ejections and sweeps, the dominant contributors to the Reynolds shear stress, over the rough wall. Based on two-point correlations between the velocity fluctuations and between the velocity fluctuations and swirling strength, it was concluded that both wall roughness and particles modified the turbulence structure by increasing the size of the larger-scale structures. The idea of eddies growing from the wall, thereby enhancing communication between the inner layer and outer parts of the flow, has implications for wall-layer models that assume that the outer layer is detached from the turbulence in the inner region.