Experiments on Stratified Multiphase Plumes

Buoyant plumes are flows of great interest to engineers and geologists alike with applications varying from chemical engineering processes to explosive volcanic eruption columns. Single-phase plumes have been well studied and the flow’s behaviour is generally well understood, however many examples in both industry and the natural world consist of a secondary dispersed phase of either bubbles or dense particles. The presence of multiple phases in a plume significantly complicates the flow dynamics, especially when rising through density stratified environments such as the ocean or the atmosphere. In this thesis, four experimental studies are presented investigating the dynamic behaviour of both particle-laden plumes and bubble plumes in stratified ambients. Experiments on stratified particle-laden plumes have enabled five steady-state flow regimes to be identified and subsequently characterised using a criterion for the onset of ambient convection and the ratio of particle to fluid buoyancy flux at the source. Measurements of plume height are compared to theoretical models within the literature and are shown to be successful for pure plumes rising through quiescent environments, however not for those rising through particle-induced convection. Through discrete measurements taken within the convection column surrounding the plume, predictions for the local values of density and particle concentration are produced allowing the plume heights to be predicted through only a minor adjustment to simple plume theory. Other models to predict the radial extent of ambient convection, secondary intrusion height and various particle concentrations are also presented. Weak bubble plumes were experimentally studied to understand both the dynamics of the spreading intrusions and the mass transfer of dissolved species to the environment. Bubble plumes with large non-dimensional slip velocities create multiple spreading events and upon comparison with well known scaling, were determined to spread three times slower than an isolated intrusion at large radial distances when viscosity is important. Measurements along the spreading intrusions showed the presence of a mixing region where concentration of dissolved species decays and a non-mixing region where concentration remains constant. A diffusion model is developed and successfully compared to both local measurements and experimental images.Woolf Fisher Trus

Synthetic Retinoids

Chapter one is split into three sections, providing general overviews of synthetic retinoids and their biology, Pd-catalysed C-C bond forming reactions and transition metal-catalysed borylation of aromatic and vinylic C-H bonds, respectively. Chapter two details the application of sequential Ir-catalysed aromatic C-H borylations, Pd-catalysed C-C bond forming reactions and Rh-catalysed vinylic C-H borylations for the stereo-controlled synthesis of stilbene-based TTNPB retinoids. Chapter three details the application of Ir-catalysed aromatic C-H borylations, Sonogashira cross-couplings and Suzuki-Miyaura cross-couplings for the synthesis of tolan-, and biaryl-based retinoids. Chapter four details the development and applications of new RhI catalyst precursors for the dehydrogenative borylation of unactivated olefins. The dehydrogenative borylation reactions were utilised in one-pot, single solvent syntheses of 2-arylindenes from indene and arylhalides through C-H borylation and subsequent Suzuki-Miyaura cross-couplings

A Brave New Borderless World: Standardization Would End Decades of Inconsistency in Determining Proper Personal Jurisdiction in Cyberspace Cases

While various courts and numerous legal professionals have addressed the issue of inconsistent application of personal jurisdiction in cyberspace cases, the Supreme Court has yet to discuss the impact that technology might have on the analysis of personal jurisdiction; thus, many details remain unresolved. This Note examines the varying jurisdictional splits between the lower district courts, the courts of appeals, and the federal circuit court of appeals in determining the proper approach to take when dealing with Internet jurisdiction. After an examination of several key cases, this Note will explain why the Supreme Court, or the Legislature, should adopt an expanded version of the Ninth Circuit’s test in Cybersell, Inc. v. Cybersell, Inc., but with one categorical limitation, in order to standardize the test for a state’s exercise of personal jurisdiction over nonresident Internet sites. This solution merges two lines of thought and amounts to the creation of a single standardized and clear objective rule that requires “something more”—interactivity and commercialization—for non-tortious cases and the inclusion of an additional limiting factor for tortious cases in controversy. This solution fully comprehends the needs of the injured party to be made whole and couples it with the need for “something more” in order to satisfy a finding of proper personal jurisdiction over a nonresident defendant in cyberspace. Part I of this Note summarizes the traditional notions of general and specific personal jurisdiction and their applications to the physical and tangible. Part II discusses case law from several different United States district and appellate courts, analyzing the key facts on which each holding turns regarding the application of traditional jurisdiction. Part III examines the Ninth Circuit’s attempt to further clarify proper cyberspace jurisdiction in Cybersell, Inc. v. Cybersell, Inc. Part IV describes a representative sample of the different approaches and solutions legal scholars have posited to potentially solve the issue of how to properly determine cyberspace jurisdiction. Part V sets forth a workable, useful solution. Finally, the conclusion projects how the new approach will effectively adapt to future advances in technology and the positive, consistent, and stable effects a single, clear test would have on cyberspace and the Internet

A Brave New Borderless World: Standardization Would End Decades of Inconsistency in Determining Proper Personal Jurisdiction in Cyberspace Cases

While various courts and numerous legal professionals have addressed the issue of inconsistent application of personal jurisdiction in cyberspace cases, the Supreme Court has yet to discuss the impact that technology might have on the analysis of personal jurisdiction; thus, many details remain unresolved. This Note examines the varying jurisdictional splits between the lower district courts, the courts of appeals, and the federal circuit court of appeals in determining the proper approach to take when dealing with Internet jurisdiction. After an examination of several key cases, this Note will explain why the Supreme Court, or the Legislature, should adopt an expanded version of the Ninth Circuit’s test in Cybersell, Inc. v. Cybersell, Inc., but with one categorical limitation, in order to standardize the test for a state’s exercise of personal jurisdiction over nonresident Internet sites. This solution merges two lines of thought and amounts to the creation of a single standardized and clear objective rule that requires “something more”—interactivity and commercialization—for non-tortious cases and the inclusion of an additional limiting factor for tortious cases in controversy. This solution fully comprehends the needs of the injured party to be made whole and couples it with the need for “something more” in order to satisfy a finding of proper personal jurisdiction over a nonresident defendant in cyberspace. Part I of this Note summarizes the traditional notions of general and specific personal jurisdiction and their applications to the physical and tangible. Part II discusses case law from several different United States district and appellate courts, analyzing the key facts on which each holding turns regarding the application of traditional jurisdiction. Part III examines the Ninth Circuit’s attempt to further clarify proper cyberspace jurisdiction in Cybersell, Inc. v. Cybersell, Inc. Part IV describes a representative sample of the different approaches and solutions legal scholars have posited to potentially solve the issue of how to properly determine cyberspace jurisdiction. Part V sets forth a workable, useful solution. Finally, the conclusion projects how the new approach will effectively adapt to future advances in technology and the positive, consistent, and stable effects a single, clear test would have on cyberspace and the Internet

X-ray generation from and spectroscopy of a thin liquid sheet

In this thesis a fan spray nozzle design is presented that is capable of producing single micrometer thick sheets of liquid, which are stable and flat. These sheets are characterised by various interferometric techniques, and some elementary fluid dynamics calculations are employed to understand the formation of the sheet. A new experimental vacuum chamber was designed and built, and the liquid sheet jet apparatus was installed into it and run successfully in the vacuum. Soft X-ray absorption measurements were attempted, but due to problems with a lack of X-ray flux and contamination of the experimental apparatus no results have yet been obtained. The sheet was also used as a source for high harmonic generation, generating harmonics up to 50\,eV. The mechanism of high harmonic generation in the liquid is investigated, with the conclusion being reached that it is a similar mechanism to the semi-classical three step model. The effects of scattering are considered, and found to be less severe than anticipated due to correlation effects in the condensed phase.Open Acces

Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor

A process for producing polycrystalline silicon carbide includes heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent

A new mini-triaxial cell for combined high-pressure and high-temperature in situ synchrotron X-ray microtomography experiments up to 400°C and 24 MPa.

A new experimental triaxial cell for in situ synchrotron X-ray micro-computed tomography aimed at imaging small samples of (6 mm × 19 mm) at high temperatures (up to 400°C) and pressures (up to 24 MPa confining) is presented. The system has flow-through capabilities, independent axial and radial pressure control, and has been developed and tested at the 8.3.2. beamline at the Advanced Light Source. The characteristics of this new experimental rig are described, along with the challenges, mainly concerning the combination of X-ray transparency with vessel strength at high temperature, and solutions found during the development stage. An experiment involving oil shale pyrolysis under subsurface conditions, highlighting the importance of a device able to operate in this pressure and temperature range, is also introduced. The availability of this cell enables an unprecedented range of experiments in the Earth Sciences, with a special focus on subsurface geothermal processes

An expanded multilocus sequence typing scheme for propionibacterium acnes : investigation of 'pathogenic', 'commensal' and antibiotic resistant strains

The Gram-positive bacterium Propionibacterium acnes is a member of the normal human skin microbiota and is associated with various infections and clinical conditions. There is tentative evidence to suggest that certain lineages may be associated with disease and others with health. We recently described a multilocus sequence typing scheme (MLST) for P. acnes based on seven housekeeping genes (http://pubmlst.org/pacnes). We now describe an expanded eight gene version based on six housekeeping genes and two ‘putative virulence’ genes (eMLST) that provides improved high resolution typing (91eSTs from 285 isolates), and generates phylogenies congruent with those based on whole genome analysis. When compared with the nine gene MLST scheme developed at the University of Bath, UK, and utilised by researchers at Aarhus University, Denmark, the eMLST method offers greater resolution. Using the scheme, we examined 208 isolates from disparate clinical sources, and 77 isolates from healthy skin. Acne was predominately associated with type IA1 clonal complexes CC1, CC3 and CC4; with eST1 and eST3 lineages being highly represented. In contrast, type IA2 strains were recovered at a rate similar to type IB and II organisms. Ophthalmic infections were predominately associated with type IA1 and IA2 strains, while type IB and II were more frequently recovered from soft tissue and retrieved medical devices. Strains with rRNA mutations conferring resistance to antibiotics used in acne treatment were dominated by eST3, with some evidence for intercontinental spread. In contrast, despite its high association with acne, only a small number of resistant CC1 eSTs were identified. A number of eSTs were only recovered from healthy skin, particularly eSTs representing CC72 (type II) and CC77 (type III). Collectively our data lends support to the view that pathogenic versus truly commensal lineages of P. acnes may exist. This is likely to have important therapeutic and diagnostic implications

Accelerated modelling of moisture diffusion controlled drying using coupled physics informed neural network.

A coupled physics informed neural network (CPINN) was used to simulate liquid diffusion controlled drying, an energy intensive process in the food industry. The architecture of the CPINN was designed to permit the prediction of thermo-physical properties and key source and sink terms at the solution boundaries which cause the solution to be highly coupled. The CPINN structure improves upon limitations of using PINNs in low-temperature food drying simulations, most notably allowing multiple and highly coupled variables to be simulated in additional to ensuring dynamic thermo-physical properties updates. The CPINN successfully solved a system 1-D partial differential equations (PDEs), capturing phenomena such as transient moisture diffusion and heat conduction, evaporative and convective heat transfer at the drying surface and moisture loss to the drying air. A benchmark simulation was used to compare the CPINN predicted product temperature, Tˆ p, and predicted moisture content, Xˆ p, against a numeric solution. The mean absolute error for the respective comparisons was 0.12 °C and 0.0035 kg m kg s −1. Training the CPINN for the first time was the rate limiting step, requiring the greatest time to solve when compared to the numeric solution, with solution times of t cpinn = 321 min and t rk = 82.7 min, respectively, or a time reduction fraction of t r=3.9, due to generalised initialisation of the CPINN parameters. By utilising a staged transfer learning approach, t r was reduced to a range of 0.28–0.027 whilst maintaining solution accuracy, representing a 3 to 37 times faster solution. By saving a library of CPINN models, solutions at key drying conditions of interest can be rapidly evaluated at run time, meaning the saved CPINN effectively acted as a method to compress solutions of PDEs. The techniques used here show how CPINNs can be applied to coupled and multi-scale PDEs using a physics-based approach to problems in the food processing and other sectors.</p