A Simple Approach to Generating Body Force Models of Jet Engine Fans and its Application to Inlet-Fan Coupling Interaction

Modern aircraft design is seeing an increase in inflow distortions entering the engines as a consequence of modifying the size, shape, and placement of the engine and/or nacelle casing to increase propulsive efficiency and reduce weight and drag. This could take the form of increasing the fan diameter, which generally leads to a decrease in intake length to maintain lower nacelle weight, or fuselage-embedded engines. It is important to be able to predict how these changes will affect the external flow-fan interaction. High computational costs as well as a limited access to detailed fan geometry has impaired the ability of airframers to investigate these interactions. In this thesis, the objective is to present a process, which is used to create a simplified numerical model, known as a body force model, and which produces, within the framework of a fluid flow simulation, a desired fan performance without the need for detailed geometry. This body force approach uses volumetric source terms and a compressibility correction to model the blade rows. The main advantage of using this approach is that it allows for steady calculations to capture distortion effects; compared to traditional bladed unsteady calculations it reduces the computational cost by two orders of magnitude. The process determines the requirements for the fluid simulations using both a 1D analysis through the fan stage, as well as simplified blade camber shapes, and is enabled by making a series of simplifying assumptions. An example fan stage representative of one seen in modern large bypass ratio engines was created using this process, and was found to produce the desired performance to within 1%. The process is also used to create a stage which mimics the performance of NASA Stage 67. This newly created stage, as well as NASA Stage 67 are inserted into a nacelle and used to predict flow separation at varying crosswind speeds. The simplified stage was capable of reproducing the overall trends well; it over predicted the separation velocity by approximately 6% compared to NASA Stage 67

Pathing the Ṭubū\u27: Modal Theory in the Modern Tunisian Conservatory

While the eastern Arab modal system of maqāmāt has been amply explored by a variety of scholars and practitioners, the systems of melodic modes which underlie North African- Andalusian music traditions colloquially called the ṭubū‘ (s. ṭab‘) are relatively unknown outside their native regions (even within the Arabic-speaking world), and their features have not yet been explored in Western ethnomusicological literature. This thesis attempts to represent the modal theory of the ṭubū‘ found in one style of North African-Andalusian music, Tunisian ma’lūf. It offers a summary of pedagogical approaches used for teaching the ṭubū‘ in a typical conservatory and describes the melodic features associated with each of the modes that comprise a standard conservatory curriculum. It will be shown that the Tunisian ṭubū‘, which are categorized melodically, are conceptually distinct from the eastern Arab maqāmāt, which are categorized tonally. Approximately half of the ṭubū‘ covered in this study have tonics and scales which are shared with at least one other ṭab‘. The melodic signatures of a given mode are therefore as theoretically essential to its nature and classification as is its set of pitches. This study shows how these melodic signatures or properties (khāṣiyāt) are theorized, how they are demonstrated pedagogically through a mode’s masār laḥnī (melodic path), how they are used in the context of melodies in songs from the ma’lūf repertoire, and how they are used to differentiate one ṭab‘ from another when two or more ṭubū‘ share the same scale. Finally, this thesis offers different models that can be used for ṭab‘ analysis as it relates to melody, rhythm, and form

Inclusion Of Aerodynamic Effects In Multibody Dynamics

The Equations of Motion (EoM) software, developed by University of Windsor Vehicle Dynamics and Control Research Group, can be used to generate linear or linearized equations of motion for mechanical systems, and is particularly well suited to vehicle dynamics. This paper describes an effort to extend its capability to include the effects of wings on the motion of multibody systems

Junk Food Accessibility After 10 Years of a Restrictive Food Environment Zoning Policy Around Schools

Zoning has been proposed as a way of reducing unhealthy food access for youth, but little research has evaluated outcomes of proposed or existing junk food bans, and even less research has considered equity implications of such zoning policies. In this simulation study, set in the Region of Waterloo, Ontario (Canada), we examined how secondary student access to fast food restaurants and convenience stores would change under such a policy over 10 years in a mid-sized Canadian municipality. Outcomes are presented by school-level advantage (derived from the proportion of students in equity-deserving subgroups: low income, students who speak English as an additional language, and students not born in Canada). Current fast food restaurant and convenience store access was higher around schools with a higher proportion of equity-deserving students, and access remained higher around these schools even after 10 years under each policy scenario. After 10 years, the mean number of fast food restaurants and convenience stores within a 1-km network distance still exceeded five unhealthy outlets for both disadvantaged and advantaged schools, which was above the threshold associated with lower junk food consumption among youth. These findings bring into question the potential effectiveness and equity implications of restrictive zoning policies aimed at protecting youth from poor-quality food environments

Functional inaccessibility of quiescent herpes simplex virus genomes

BACKGROUND: Newly delivered herpes simplex virus genomes are subject to repression during the early stages of infection of human fibroblasts. This host defence strategy can limit virus replication and lead to long-term persistence of quiescent viral genomes. The viral immediate-early protein ICP0 acts to negate this negative regulation, thereby facilitating the onset of the viral replication cycle. Although few mechanistic details are available, the host repression machinery has been proposed to assemble the viral genome into a globally inaccessible configuration analogous to heterochromatin, blocking access to most or all trans-acting factors. The strongest evidence for this hypothesis is that ICP0-deficient virus is unable to reactivate quiescent viral genomes, despite its ability to undergo productive infection given a sufficiently high multiplicity of infection. However, recent studies have shown that quiescent infection induces a potent antiviral state, and that ICP0 plays a key role in disarming such host antiviral responses. These findings raise the possibility that cells containing quiescent viral genomes may be refractory to superinfection by ICP0-deficient virus, potentially providing an alternative explanation for the inability of such viruses to trigger reactivation. We therefore asked if ICP0-deficient virus is capable of replicating in cells that contain quiescent viral genomes. RESULTS: We found that ICP0-deficient herpes simplex virus is able to infect quiescently infected cells, leading to expression and replication of the superinfecting viral genome. Despite this productive infection, the resident quiescent viral genome was neither expressed nor replicated, unless ICP0 was provided in trans. CONCLUSION: These data document that quiescent HSV genomes fail to respond to the virally modified host transcriptional apparatus or viral DNA replication machinery provided in trans by productive HSV infection in the absence of ICP0. These results point to global repression as the basis for HSV genome quiescence, and indicate that ICP0 induces reactivation by overcoming this global barrier to the access of trans-acting factors

Tetra-μ-acetato-κ8 O:O′-bis­[(3-cyano­pyridine-κN 1)ruthenium(II,III)](Ru—Ru) hexa­fluoridophosphate 1,2-dichloro­ethane monosolvate

The title compound, [Ru2(CH3CO2)4(C6H4N2)2]PF6·C2H4Cl2, was obtained via a rapid substitution reaction in 2-propanol whereby 3-cyano­pyridine replaces the axial water mol­ecules in the diaquatetra-μ-acetato-diruthenium(II,III) hexa­fluorido­phosphate starting material. The product rapidly precipated and crystals were grown from 1,2-dichloro­ethane. The 1,2-dichloro­ethane mol­ecule of solvation exhibits disorder with two different orientations [occupancy ratio 0.51 (6):0.49 (6)]. All three parts, the cation, the anion and the disordered solvent mol­ecule lie on crystallographic inversion centers. The Ru—Ru bond length of 2.2702 (6) Å fits nicely into the range seen for similar complexes and correlates well with the reduction potential of the complex and donor strength of the axial ligand, 3-cyano­pyridine, as postulated in a previous study [Vamvounis et al. (2000 ▶). Inorg. Chim. Acta, 305, 87–98]. The 3-cyano­pyridine ligands orient themselves in an anti configuration with respect to each other and the Ru—Ru—N angle [174.27 (7)°] is close to being linear

Development of a teen-informed coding tool to measure the power of food advertisements

The food-related information environment, comprised of food and beverage advertising within one’s surroundings, is a growing concern for adolescent health given that food marketing disproportionately targets adolescents. Despite strong public interest concerning the effects of food marketing on child health, there is limited evidence focused on outdoor food advertising in relation to teenage diets, food purchasing, and perceptions. Further, limited research has considered both the exposure to and influence of such advertisements. This study used a novel multi-method approach to identify and quantify the features of outdoor food and beverage advertisements that are most effective at drawing teenagers into retail food establishments. An environmental audit of outdoor advertisements and consultations with youth were used to: (1) identify teen-directed food marketing techniques; (2) validate and weigh the power of individual advertising elements; and, (3) develop a teen-informed coding tool to measure the power of food-related advertisements. Results indicate that marketing power is a function of the presence and size of teen-directed advertisement features, and the relative nature of each feature is an important consideration. This study offers a quantitative measurement tool for food environment research and urges policymakers to consider teen-directed marketing when creating healthy communities