Reducing secondary leakage is a common challenge in numerous machines, particularly in steam and gas turbines. Too large leakage in seals produces a substantial loss in efficiency and power delivery with an increase in specific fuel consumption. Various seal types exist, each with unique advantages and disadvantages as per leakage, power loss, and wear. Labyrinth seals are most common due to their simple design and low cost. Their main drawback is a too high leakage due to enlarged (worn) clearances when a rotor vibrates. More complicated seal types, such as brush seals can withstand rotor excursions and ensure lower leakage rates than with labyrinth seals. Brush seals utilize a bristle bed which contacts the rotor and wears out thereby reducing leakage performance. The HALOTM seal, an all-metal seal with flexibly supported shoes, is engineered as a clearance control seal to reduce leakage even more, in particular for operation with high pressure differentials and with high surface rotor speeds. Static leakage tests with hot air at a high temperature (max. 300°C) conducted in a test rig holding a labyrinth seal and a novel all-metal seal (HALOTM seal), both of the same diameter, length and clearance, show the novel seal leaks ~1/5 the flow of a labyrinth seal for pressure ratios (Ps/Pa) > 3.5. The savings in leakage are maximized during operation at high pressure differentials. Leakage measurements with a rotor spinning to a maximum speed of 2,700 rpm (surface speed = 23.6 m/s) produce a slight decrease in leakage with increasing rotor speed. The research product is a reliable leakage data base enabling the application of a state of the art sealing technology that increases system efficiency by reducing leakage and extends maintenance intervals by eliminating wear of components.

Thesis (M.S.)--Ohio State University. / Bibliography: leaves 118-128. Available online via OhioLINK's ETD Center

What is a library? It is easy to envision the ordinary and ubiquitous library that we are all familiar with, but is there more to libraries that is yet to be explored? What is a concept of a library? What do we as architects envision as the design for a library? The Thesis is built upon the idea that Libraries should be designed out of stories, because stories are written in books and books are found in libraries. According to the writer Borges, the concept of a library, is that it is composed of an indefinite and infinite number of galleries, which are connected by vestibules. Anyone in this library can see upper and lower from any galleries and "all are repeated in the same disorder which constitutes an order!" ... The Thesis explores this concept of finding the order through repeated disorders, in another words, a labyrinth. The writer Umberto Eco has said in one of his novels: "How beautiful the world would be if there were a procedure for moving through labyrinths." In search of this "beauty" in the world, through this thesis I have explored and found the procedure for designing a library. / Master of Architecture / In Architecture, there is a fine balance between imagination and practicality. Practicality is often rooted in the physical world and can be determined by more materialistic and technical aspects. Imagination on the other hand can be subjective to the architect without having any constraints. With a program idea of a library in my mind, the thesis began with reading stories about a library. Because stories are written in books and books are found in libraries, the manifestation of the design is driven by the "stories" and it defines the pure existence of the building. This work studies the balance between the functional and the non fictional world, through these stories. The main program of the thesis consists of two libraries. These two libraries are located in the Georgetown neighborhood of Washington, D.C. The south side of the library belongs to the public and the north side belongs to the private. Throughout the design process, the libraries constantly explore the balance of the imaginative and the practical world. The thesis questions the importance of this approach and how we as architects and designers define programs for buildings. The thesis further questions how references of the surrounding context implement into the design both through forms and materiality.

Having historical, cultural, and religious roots, humans have been walking the path of the labyrinth for centuries. From seashores to cathedral floors, the labyrinth is seen as a symbolic search for one's center. The labyrinth has experienced a revival in modern life, showing up everywhere from rehabilitation centers and hospitals, to prisons and backyard landscapes across this country. The labyrinth has emerged as a form that can help humans find their internal center and place of emotional stability. Having walked the labyrinth and believing in its healing properties, I became interested in the symbol itself. I was intrigued by the way the symbol was actually an architectural element that told the narrative of the culture that built it. While the labyrinth was on church floors in medieval times, its revival in modern times seems to be located in the outdoor environment. Since Landscape Architecture is a field based on the creation of safe and pleasing outdoor environments for humans, I chose the labyrinth as a way of looking at "experience" and "contemplation" in the landscape, and how the design(the creation of form) of this object contributes to the analysis. Wanting to complete this analysis by actually building a labyrinth, I was approached by the Sanctuaries Unique Garden Center in Richmond, Virginia, and asked to design and build a labyrinth. Providing Sanctuaries with conceptual designs of one way paths, a final design was settled on and the project was built. The thesis will highlight the theory, design, and construction surrounding the object called a "labyrinth." c44fb6c5-1ea6-4f7d-89f1-2e62511b85f8,"Health outcomes following a traumatic event are an important aspect of recovery from any type of trauma. Further, distress and psychopathology, specifically Posttraumatic Stress Disorder (PTSD), have been shown to have a significant impact on physical health recovery post-trauma. The current study utilized a sample of 56 (48 women, 8 men) residential fire survivors to examine the potential mediating effect of PTSD and PTSD symptom subclusters. Participants were interviewed four months after a residential fire and were assessed on levels of exposure to the fire (Fire Questionnaire & Resource Loss Scale), PTSD symptomology (Anxiety Disorder Interview Schedule), and somatic health complaints (Brief Symptom Inventory). Consistent with previous findings, PTSD was found to mediate the relationship between exposure to a traumatic event and reporting of health symptoms. Further, the increased arousal subcluster was found to mediate the aforementioned relationship; the avoidance symptom subcluster was found to partially mediate the same relationship. Implications of results of the current project are discussed with regard to the impact of trauma on survivors' health, along with recommendations for further research. / Master of Landscape Architecture

Darbo objektas - trijų autorių – skirtingų kultūrų atstovų romanai, kuriuos jungia labirinto tematika. Labirinto tema šiuose romanuose yra pagrindinė kūrinio idėja, konstruojanti siužetą. Vienas iš šio darbo tikslų yra išsiaiškinti, kokias reikšmes slepia labirinto simbolika ir kokį poveikį pastarasis simbolis daro meno pasauliui. Kitas tikslas, susijęs su pasirinkta tyrimo metodologija, yra palyginti, kuo labirinto temos traktuotė yra panaši ir kuo skiriasi pasirinktuose kūriniuose. Darbe keliama hipotezė, kad labirinto simbolis glaudžiai susijęs su aptariamų autorių estetinėmis nuostatomis. Šią hipotezę įrodyti bus pagrindinis tyrėjo uždavinys. Darbo pabaigoje daromos išvados, kad labirinto simbolis išreiškia darbe analizuojamų autorių estetines pažiūras, artimas postmoderniai sampratai. Labirinto vaizdinio pagalba šie rašytojai kuria daugiaprasmį, atvirą tekstą, kuriame daug postmodernistiniam romanui būdingų bruožų: autoriaus mirtis, prasmės atsisakymas, proto ir logikos nuvertinimas, spontaniškumo, atsitiktinumo iškėlimas, ribos tarp tikrovės ir fikcijos išnykimas, fragmentiškumas, žaidimas su skaitytoju ir kt. / The object of this research is three novels written by authors belonging to three different cultures, namely “And Those Look out of Windows Be Dimmed“, by Lithuanian prosaist Saulius Tomas Kondrotas, “In the Labyrinth”, by French novelist Alain Robbe – Grillet and “The Name of the Rose", by Italian author Umberto Eco. All these novels are connected by the theme of labyrinth, which in all the three works is the main idea, making up the plot. These novels are familiar to the poetics of the “New Novel” and postmodern mindset. The main aim of this research, related to the chosen methodology, is to compare how the approach to the theme of labyrinth is similar and how it differs in all the three novels, enlisted above. This research tries to find out what meanings does the symbol of labyrinth hide in itself and what impact does it have to the World of Art. The hypothesis that the symbol of labyrinth is closely associated with the aesthetic views of these three authors is also raised. The main aim of the researcher is to prove this hypothesis. The conclusions of the research state, that previously mentioned symbol expresses discussed authors’ attitude to the world. With the help of the image of labyrinth, these authors create open text, having many meanings and traits of postmodern novel, namely the death of an author, the refusal of meaning, devaluation of reason and logic, elevation of spontaneity and coincidence, disappearance of the boundaries between fiction and reality... [to full text]

The flow field in an annular seal is simulated for synchronous circular whirl orbits with 60Hz whirl frequency and a clearance/radius ratio of 0.0154 using the Fluent Computational Fluid Dynamics (CFD) code. Fluent's Moving Reference Frame model (MRF) is used to render the flow quasi-steady by making transformations to a rotating frame. The computed flow fields for velocity, pressure and shear stress measurements are compared with the experimental data of Winslow, Thames and Cusano. The CFD predictions are found to be in good agreement with the experimental results. The present CFD methodology can be extended to other whirl frequencies and clearances. The dynamic wall pressure distributions in an annular seal for non-circular whirl orbits were obtained using CFD. The simulations were performed using a time dependant solver utilizing Fluent's Dynamic Mesh model and User Defined Functions (UDFs). The wall pressure distributions obtained from the simulations are compared with data of Cusano. The CFD simulations over predicted the pressure field when compared to experimental results however the general trends in pressure contours are similar. The flow fields for varying rotor eccentricities are also studied by performing coordinate transformations and rendering the flow quasi-steady at set eccentricities using Fluent's MRF model. The computed velocity and pressure fields are compared with the time dependant solution obtained using Fluent's Dynamic Mesh model and UDFs for the same eccentricity. Good agreement in the velocity fields is obtained; however the pressure fields require further investigation. 2D Labyrinth seal simulations were performed for comparisons with experimental LDA data from Johnson. The velocity fields match the experimental LDA data to a fair degree of extent; however, Fluent simulations under predicted the secondary recirculation zones in Labyrinth Backward Swirl (LBS) case.

The labyrinth seal is widely used in turbomachinery to minimize or control leakage between areas of different pressure. The present investigation numerically explored the effect of damage and wear of the labyrinth seal on the turbomachinery flow and temperature fields. Specifically, this work investigated: (1) the effect of rubgroove downstream wall angle on seal leakage, (2) the effect of tooth bending damage on the leakage, (3) the effect of tooth "€œmushrooming"€ damage on seal leakage, and (4) the effect of rub-groove axial position and wall angle on gas turbine ingress heating. To facilitate grid generation, an unstructured grid generator named OpenCFD was also developed. The grid generator is written in C++ and generates hybrid grids consisting primarily of Cartesian cells. This investigation of labyrinth seal damage and wear was conducted using the Reynolds averaged Navier-Stokes equations (RANS) to simulate the flows. The high- Reynolds k - Model and the standard wall function were used to model the turbulence. STAR-CD was used to solve the equations, and the grids were generated using the new code OpenCFD. It was found that the damage and wear of the labyrinth seal have a significant effect on the leakage and temperature field, as well as on the flow pattern. The leakage increases significantly faster than the operating clearance increase from the wear. Further, the specific seal configuration resulting from the damage and wear was found to be important. For example, for pure-bending cases, it was found that the bending curvature and the percentage of tooth length that is bent are important, and that the mushroom radius and tooth bending are important for the mushrooming damage cases. When an abradable labyrinth seal was applied to a very large gas turbine wheelspace cavity, it was found that the rub-groove axial position, and to a smaller degree, rub-groove wall angle, alter the magnitude and distribution of the fluid temperature.

Afhandling - Copenhagen. / Summary in English and Danish. Bibliography: p. [131]-134.

In this study Lezama’s Paradiso is “the mysterious labyrinth of the cognitive image,” a metaphor for his search for ultimate enlightenment--knowledge of super nature toward the Highest Good. The Preamble introduces the novel Paradiso as his poetic sum of knowledge generated by the Cognitive Eros like an encyclopedic narrative with revelation at the center. Chapter One presents labyrinth fundamentals and the mythic method to analyze the novel. It identifies a heightened perception or sensation, cognition, and imagination as “new” senses “beyond reason” needed to read this “new other” novel. It also explains how the author’s clues aid comprehension, how the poetic word illuminates a fourfold method for interpretation, and how the double structure of the narrative superimposes a circuitous pathway of multicursal storylines and descriptions of Old World images upon a linear unicursal surface narrative. Chapter Two examines three cognitive images in Lezama’s labyrinth: Confluence analyzes how multiple streams of thought and images flow from chaos into order in the poet’s mind and how the labyrinth’s principle of opposition represents the convergence of contradictory images whose combination will inspire other images. Androgyne or Oneness illustrates the nature of creativity--how symmetrical opposite images unite or copulate to germinate other imagery. Figure and Revelation show Lezama’s use of Scriptural figura to represent the prefigurative sense of his writing. Chapter Three interprets Lezama’s own labyrinthine method and steps for interpreting Paradiso derived from his scrutiny of “the other” analogous novel, Julio Cortázar’s Rayuela. The study concludes that Paradiso delivers Lezama’s Delphic Course, a systematized literary orientation based on the belief that each text transmits wisdom. The protagonist/reader undergoes Anthropophany, is transformed into a learned interpreter and a higher self toward manifestation in the image of the Word/God. With the author-protagonist as mentor Paradiso proclaims Lezama’s ideal program of cultural, intellectual, ethical, and spiritual formation of the individual after the classic Greek Paideia, parallel to the way of purification and redemption achieved through the Paideia of Christ. Finally, the text embodies Lezama’s crusade to restore Cuba as a bridge for cultural exchange and development between the Old World and the New World. / text

Iroquois genes encode a family of highly conserved TALE homeodomain transcription factors that are involved in multiple developmental processes. Physiological tests indicated that Irx3 and Irx5 mutant mice displayed hearing impairment. However, the functions of these two genes during inner ear development are not known. The aim of this study is to characterize the roles of Irx3 and Irx5 during mammalian inner ear development using mouse models, in order to reveal the underlying mechanism for the hearing abnormality in the mutants. Two mouse mutants, Irx3tauLacZ and Irx3flox5EGFP with β-gal and EGFP reporters, were analyzed to examine the expression of these two genes in the otic vesicle and cochlear epithelium. In the otocyst, both Irx3 and Irx5 were expressed in the ventral-medial region. Irx5 expression was restricted to the non-sensory domain of the cochlear epithelia, while Irx3 was widely expressed, including the auditory sensory organ, the organ of Corti. The overlapping expression patterns of Irx3 and Irx5 suggest that they may share redundant functions. To investigate the roles of Irx3 and Irx5 during inner ear development, phenotypic analysis was performed on Irx3-/-, Irx5-/- and Irx3/5-/- mutant embryos. As shown by paint-filling analysis, Irx3/5-/- displayed shortened cochlear duct, enlarged cochlear lumen with fused sensory organ. Whole-mount phalloidin staining of hair cell bundles showed that Irx3-/- displayed occasional ectopic inner hair cells. Moreover, only supernumerary vestibular hair cell-like cells were developed in Irx3/5-/- mutant. These results suggest that Irx3 and Irx5 are required for inner ear morphogenesis and the formation of organ of Corti. To understand the effect of Irx3 and Irx5 in the cellular patterning of the cochlea, mutant cochleae were analyzed with markers for different regions of the cochlear epithelia. Altered expression domain of MyoVIIa, Sox2 and Gata2 in Irx3/5-/- cochlea revealed that the boundary between the Kolliker’s organ and the organ of Corti was lost and the location of sensory and non-sensory region was shifted. These results imply that Irx3 and Irx5 function in the establishment of the sensory/non-sensory boundary. It is known that p27kip1 regulates the wave of cell cycle exit in the developing organ of Corti and Sox2 takes part in prosensory specification. To explore the underlying reason for the patterning defects in Irx3/5-/- mutant, cochlear duct from prosensory stages were analyzed. Irx3/5-/- showed altered Sox2 and p27kip1 expression, with expanded prosensory domain and disrupted cell cycle exit. Ectopic prosensory proliferation was detected in the middle turn of the cochlear duct at E13.5 by BrdU incorporation assay. Therefore, Irx3 and Irx5 may participate in the subdivision of sensory territory in developing cochlea by controlling prosensory proliferation. In summary, this study demonstrates that Irx3 and Irx5 cooperate in multiple aspects of inner ear development: an early role to regulate prosensory proliferation and cell cycle exit; a second role to regulate cellular patterning of the cochlear duct by controlling the setting of sensory/non-sensory boundaries in the cochlea; a later role to regulate inner ear morphogenesis. This study supports the idea that Irx3 and Irx5 act as patterning genes during vertebrate evolution. / published_or_final_version / Biochemistry / Master / Master of Philosophy