Relevant bibliographies by topics / Elliptical holes

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers

Academic literature on the topic 'Elliptical holes'

Author: Grafiati
Published: 4 June 2021
Last updated: 7 February 2022

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Journal articles on the topic "Elliptical holes"

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Hirth, J. P. "Dislocations within elliptical holes." Acta Materialia 47, no. 1 (December 1998): 1–4. http://dx.doi.org/10.1016/s1359-6454(98)00351-6.

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Wang, Shuang, Cun-Fa Gao, and Zeng-Tao Chen. "Interaction between two nanoscale elliptical holes with surface tension." Mathematics and Mechanics of Solids 24, no. 5 (September 28, 2018): 1556–66. http://dx.doi.org/10.1177/1081286518801051.

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In this paper, the plane problem of two elliptical nanoscale holes with surface tension is investigated. Firstly, the basic equations are given via the complex variable methods. Then, the stress boundary condition caused by surface tension is derived through the integral-form Gurtin–Murdoch model. The problem is finally solved by the conformal mapping along with the series expansion methods. The results show that the stress field decreases as the two holes become further away from each other. When the distance between the two holes is more than three times the sum of their sizes, the interaction between the two holes can be neglected. In addition, the stress field is greatly influenced by the orientation, aspect ratio and size of the holes. The positions of the maximum hoop stress are also discussed. When the two elliptical holes are put close horizontally, the hoop stress around one hole usually obtain its maximum at the endpoint close to the other hole. However, if one elliptical hole is not horizontal, the hoop stress around it will no longer attain its maximum at the endpoints. Another exception is that when one elliptical hole becomes larger, the hoop stress around the smaller hole would tend to achieve a local minimum at the endpoint close to the larger hole.
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Persson, E., and E. Madenci. "Composite laminates with elliptical pin-loaded holes." Engineering Fracture Mechanics 61, no. 2 (September 1998): 279–95. http://dx.doi.org/10.1016/s0013-7944(98)00041-1.

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Bing, Pibin, Shichao Huang, Jialei Sui, Hua Wang, and Yongen Ren. "A sensor based on D-shaped photonic crystal fiber with elliptical holes." Modern Physics Letters B 33, no. 32 (November 20, 2019): 1950397. http://dx.doi.org/10.1142/s0217984919503974.

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A sensor based on D-shaped photonic crystal fiber (PCF) with elliptical holes is designed and numerical studied by finite element method (FEM). The refractive index (RI) of analyte can be detected by using surface plasma resonance effect and optical fiber with elliptical holes can solve the phase matching problem. The size of central hole, the major axis of the two elliptical holes near polishing plane in first layer and polishing depth are adjusted to explore the influence of these parameters on wavelength sensitivity and amplitude sensitivity of the sensor. Polishing depth has a great influence on wavelength sensitivity of the sensor. As a result, higher sensitivity is obtained with larger polishing depth in the range of 1.33–1.39 and smaller polishing depth is more suitable with RI changing from 1.39–1.42. The wavelength sensitivity of the designed sensor is 10,200 nm/RIU, which means the designed sensor has a promising application prospect.
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Kovačević, Andjelka B., Jian-Min Wang, and Luka Č. Popović. "Kinematic signatures of reverberation mapping of close binaries of supermassive black holes in active galactic nuclei." Astronomy & Astrophysics 635 (February 28, 2020): A1. http://dx.doi.org/10.1051/0004-6361/201936398.

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Context. An unresolved region in the relative vicinity of the event horizon of a supermassive black holes (SMBH) in active galactic nuclei (AGN) radiates strongly variable optical continuum and broad-line emission flux. These fluxes can be processed into two-dimensional transfer functions (2DTF) of material flows that encrypt various information about these unresolved structures. An intense search for kinematic signatures of reverberation mapping of close binary SMBH (SMBBH) is currently ongoing. Aims. Elliptical SMBBH systems (i.e. both orbits and disc-like broad-line regions (BLR) are elliptic) have not been assessed in 2DTF studies. We aim to numerically infer such a 2DTF because the geometry of the unresolved region is imprinted on their optical emission. Through this, we determine their specific kinematical signatures. Methods. We simulated the geometry and kinematics of SMBBH whose components are on elliptical orbits. Each SMBH had a disc-like elliptical BLR. The SMBHs were active and orbited each other tightly at a subparsec distance. Results. Here we calculate for the first time 2DTF, as defined in the velocity-time delay plane, for several elliptical configurations of SMBBH orbits and their BLRs. We find that these very complex configurations are clearly resolved in maps. These results are distinct from those obtained from circular and disc-wind geometry. We calculate the expected line variability for all SMBBH configurations. We show that the line shapes are influenced by the orbital phase of the SMBBH. Some line profiles resemble observed profiles, but they can also be much deformed to look like those from the disc-wind model. Conclusions. First, our results imply that using our 2DTF, we can detect and quantify kinematic signatures of elliptical SMBBH. Second, the calculated expected line profiles share some intriguing similarities with observed profiles, but also with some profiles that are synthesised in disc-wind models. To overcome the non-uniqueness of the spectral line shapes as markers of SMBBH, they must be accompanied with 2DTF.
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HEWIDY, M. S., and V. K. JAIN. "On the production of elliptical holes by ECM." International Journal of Production Research 25, no. 3 (March 1987): 433–45. http://dx.doi.org/10.1080/00207548708919851.

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Fabian, A. C., and C. R. Canizares. "Do massive black holes reside in elliptical galaxies?" Nature 333, no. 6176 (June 1988): 829–31. http://dx.doi.org/10.1038/333829a0.

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Forskitt, M., J. R. Moon, and P. A. Brook. "Elastic properties of plates perforated by elliptical holes." Applied Mathematical Modelling 15, no. 4 (April 1991): 182–90. http://dx.doi.org/10.1016/0307-904x(91)90007-c.

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Geerthana, S., A. Sivanantha Raja, and D. Shanmuga Sundar. "Design and optimization of photonic crystal fiber with improved optical characteristics." Journal of Nonlinear Optical Physics & Materials 24, no. 04 (December 2015): 1550051. http://dx.doi.org/10.1142/s0218863515500514.

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A highly birefringent photonic crystal fiber (PCF) with large nonlinearity, low dispersion and low confinement loss is designed by introducing a solid elliptical core structure with spiral lattice of circular air holes as a cladding. The dependence of different geometrical parameters, such as pitch size, diameter of air holes and arrangement of air holes are investigated. By optimizing the available parameters, the designed elliptical–spiral PCF offers high birefringence up to 0.005264, high nonlinearity up to 8683.59[Formula: see text]W[Formula: see text][Formula: see text]km[Formula: see text], low chromatic dispersion of [Formula: see text][Formula: see text]ps/nm/km, and low confinement loss of 0.00305[Formula: see text]dB/km within a wide wavelength range of 1000–2000[Formula: see text]nm.
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Kovačević, Andjelka B., Yu-Yang Songsheng, Jian-Min Wang, and Luka Č. Popović. "Probing the elliptical orbital configuration of the close binary of supermassive black holes with differential interferometry." Astronomy & Astrophysics 644 (December 2020): A88. http://dx.doi.org/10.1051/0004-6361/202038733.

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Context. Obtaining detections of electromagnetic signatures from the close binaries of supermassive black holes (CB-SMBH) is still a great observational challenge. The Very Large Telescope Interferometer (VLTI) and the Extremely Large Telescope (ELT) will serve as a robust astrophysics suite offering the opportunity to probe the structure and dynamics of CB-SMBH at a high spectral and angular resolution. Aims. Here, we explore and illustrate the application of differential interferometry on unresolved CB-SMBH systems in elliptical orbital configurations. We also investigate certain peculiarities of interferometry signals for a single SMBH with clouds in elliptical orbital motion. Methods. Photocentre displacements between each SMBH and the regions in their disc-like broad line regions (BLR) appear as small interferometric differential phase variability. To investigate the application of interferometric phases for the detection of CB-SMBH systems, we simulated a series of differential interferometry signatures, based on our model comprising ensembles of clouds surrounding each supermassive black hole in a CB-SMBH. By setting the model to the parameters of a single SMBH with elliptical cloud motion, we also calculated a series of differential interferometry observables for this case. Results. We found various deviations from the canonical S-shape of the CB-SMBH phase profile for elliptically configured CB-SMBH systems. The amplitude and specific shape of the interferometry observables depend on the orbital configurations of the CB-SMBH system. We get distinctive results when considering anti-aligned angular momenta of cloud orbits with regard to the total CB-SMBH angular momentum. We also show that their velocity distributions differ from the aligned cloud orbital motion. Some simulated spectral lines from our model closely resemble observations from the Paα line obtained from near-infrared AGN surveys. We found differences between the “zoo” of differential phases of single SMBH and CB-SMBH systems. The “zoo” of differential phases for a single SMBH take a deformed S shape. We also show how their differential phase shape, amplitude, and slope evolve with various sets of cloud orbital parameters and the observer’s position. Conclusions. We calculate an extensive atlas of the interferometric observables, revealing distinctive signatures for the elliptical configuration CB-SMBH. We also provide an interferometry atlas for the case of a single SMBH with clouds with an elliptical motion, which differs from those of a CB-SMBH. These maps can be useful for extracting exceptional features of the BLR structure from future high-resolution observations of CB-SMBH systems, but also of a single SMBH with clouds in an elliptical orbital setup.
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Dissertations / Theses on the topic "Elliptical holes"

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Snyder, Gregory Frantz. "Modeling Spatially and Spectrally Resolved Observations to Diagnose the Formation of Elliptical Galaxies." Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:10893.

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In extragalactic astronomy, a central challenge is that we cannot directly watch what happens to galaxies before and after they are observed. This dissertation focuses on linking predictions of galaxy time-evolution directly with observations, evaluating how interactions, mergers, and other processes affect the appearance of elliptical galaxies. The primary approach is to combine hydrodynamical simulations of galaxy formation, including all major components, with dust radiative transfer to predict their observational signatures. The current paradigm implies that a quiescent elliptical emerges following a formative starburst event. These trigger accretion onto the central supermassive black hole (SMBH), which then radiates as an active galactic nucleus (AGN). However, it is not clear the extent to which SMBH growth is fueled by these events nor how important is their energy input at setting the appearance of the remnant. This thesis presents results drawing from three phases in the formation of a typical elliptical: 1) I evaluate how to disentangle AGN from star formation signatures in mid-infrared spectra during a dust-enshrouded starburst, making testable predictions for robustly tracing SMBH growth with the James Webb Space Telescope ; 2) I develop a model for the rate of merger-induced post-starburst galaxies selected from optical spectra, resolving tension between their observed rarity and merger rates from other estimates; and 3) I present results from Hubble Space Telescope imaging of elliptical galaxies in galaxy clusters at 1 < z < 2, the precursors of present-day massive clusters with \(M \sim10^{15}M_{\odot}\), demonstrating that their stars formed over an extended period and ruling out the simplest model for their formation history. These results lend support to a stochastic formation history for ellipticals driven by mergers or interactions. However, significant uncertainties remain in how to evaluate the implications of galaxy appearance, in particular their morphologies across cosmic time. In the final chapter, I outline an approach to build a "mock observatory" from cosmological hydrodynamical simulations, with which observations of all types, including at high spatial and spectral resolutions, can be brought to bear in directly constraining the physics of galaxy formation and evolution.
Astronomy
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Issa, Nader. "Modes and propagation in microstructured optical fibres." University of Sydney. Physics and Optical Fibre Technology Centre, 2005. http://hdl.handle.net/2123/613.

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Microstructured optical fibres (MOFs), also commonly called photonic crystal fibres or holey fibres, describe a type of optical fibre in which continuous channels of (typically) air run their entire length. These `holes' serve to both confine electromagnetic waves within the core of the fibre and to tailor its transmission properties. In order to understand and quantify both of these functions, a new computational algorithm was developed and implemented. It solves for the eigenvalues of Maxwell's wave equations in the two-dimensional waveguide cross-section, with radiating boundary conditions imposed outside the microstructure. This yields the leaky modes supported by the fibre. The boundary conditions are achieved exactly using a novel refinement scheme called the Adjustable Boundary Condition (ABC) method. Two implementations are programmed and their computational efficiencies are compared. Both use an azimuthal Fourier decomposition, but radially, a finite difference scheme is shown to be more efficient than a basis function expansion. The properties of the ABC method are then predicted theoretically using an original approach. It shows that the method is highly efficient, robust, automated and generally applicable to any implementation or to other radiating problems. A theoretical framework for the properties of modes in MOFs is also presented. It includes the use of the Bloch-Floquet theorem to provide a simpler and more efficient way to exploit microstructure symmetry. A new, but brief study of the modal birefringence properties in straight and spun fibres is also included. The theoretical and numerical tools are then applied to the study of polymer MOFs. Three types of fibres are numerically studied, fabricated and characterised. Each is of contemporary interest. Firstly, fabrication of the first MOFs with uniformly oriented elliptical holes is presented. A high degree of hole ellipticity is achieved using a simple technique relying on hole deformation during fibre draw. Both form and stress-optic birefringence are characterized over a broad scaled-wavelength range, which shows excellent agreement with numerical modelling. Secondly, an analysis of leaky modes in real air core MOFs, fabricated specifically for photonic band gap guidance, is then used to identify alternative guiding mechanisms. The supported leaky modes exhibit properties closely matching a simple hollow waveguide, weakly influenced by the surrounding microstructure. The analysis gives a quantitative determination of the wavelength dependent confinement loss of these modes and illustrates a mechanism not photonic band gap in origin by which colouration can be observed in such fibres. Finally, highly multimode MOFs (also called `air-clad' fibres) that have much wider light acceptance angles than conventional fibres are studied. An original and accurate method is presented for determining the numerical aperture of such fibres using leaky modes. The dependence on length, wavelength and various microstructure dimensions are evaluated for the first time for a class of fibres. These results show excellent agreement with published measurements on similar fibres and verify that bridge thicknesses much smaller than the wavelength are required for exceptionally high numerical apertures. The influence of multiple layers of holes on the numerical aperture and capture efficiency are then presented. It shows that a substantial increase in both these parameters can be achieved for some bridge thicknesses. Simple heuristic expressions for these quantities are given, which are based on the physical insight provided by the full numerical models. The work is then supported by the first fabrication attempts of large-core polymer MOFs with thin supporting bridges. These fibres exhibit relatively high numerical apertures and show good agreement with theoretical expectations over a very wide scaled-wavelength range.
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Mancino, Antonio. "On the structural and dynamical properties of a new class of galaxy models with a central BH." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18722/.

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This thesis work focuses on the dynamical properties of two-component galaxy models characterized by a stellar density distribution described by a Jaffe profile, and a galaxy (stars plus dark matter) density distribution following a r^(-3) shape at large radii. The dark matter (hereafter, DM) density profile is defined by the difference between the galaxy and the stellar profiles. The orbital structure of the stellar component is described by the Osipkov-Merritt (OM) radial anisotropy, and that of the DM halo is assumed isotropic; a black hole (BH) is also added at the center of the galaxy. The thesis is organized as follows. In Chapter 2 the main structural properties of the models are presented, and the conditions required to have a nowhere negative and monothonically decreasing DM halo density profile are derived; a discussion is also given of how the DM component can be built in order to have the same asymptotical behaviour, in the outer regions and near the center, as the Navarro-Frenk-White (NFW) profile. In Chapter 3 an investigation of the phase-space properties of the models is carried out, both from the point of view of the necessary and sufficient conditions for consistency, and from the direct inspection of the distribution function; the minimum value of the anisotropy radius for consistency is derived in terms of the galaxy parameters. In Chapter 4 the analytical solution of the Jeans equations with OM anisotropy is presented, together with the projection of the velocity dispersion profile at small and large radii. Finally, in Chapter 5 the global quantities entering the Virial theorem are explicitly calculated; these can be used for energetic considerations that are briefly mentioned, and allow us to determine the fiducial anisotropy limit required to prevent the onset of Radial Orbit Instability as a function of the galaxy parameters. The main results are summarized in Chapter 6, and some technical details are given in the Appendices.
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Cheng, Chia Hsuan, and 鄭嘉璿. "The Formation of Supermassive Binary Black Holes in Elliptical Galaxies." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/43502072329650587136.

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碩士
國立清華大學
物理系
104
We study the evolution of two supermassive black holes in the galaxy. We investigate whether two black holes can form a bound binary system within the age of the universe. Since the dynamical friction is the major physical process to determine the early stage of the formation of binary supermassive black holes, we also investigate its variables and other parameters such as the mass and the initial positions of the black holes. We use the simulation to study the behavior of two black holes in the galaxy. The results show that the evolution in the Hernquist model is faster than the one in the Plummer model. The former’s critical black hole mass to become gravitational bound is roughly one tenth of the latter’s. Hence it is easier for the black holes to become a bound binary in the Hernquist model.
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Chang, Tsang-Huai, and 張蒼懷. "Study of the Characteristic Effect of Elliptical Holes Polishing by Rotating Abrasive Flow Machining." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/28811666725888207114.

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Tsai, Tsungyen, and 蔡宗諺. "BEM Analysis for Stress Concentrations of Bending Problem of Anisotropic Plates Containing Two Elliptical Holes." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/80496427955875267379.

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碩士
國立臺灣大學
應用力學研究所
103
This work uses a new boundary integral equation (BIE) and finite element method (FEM) to analyze an infinite anisotropic plate containing two elliptic/circular holes subjected to remote bending or twisting moments. The foundation of the boundary integral equation is the classical plate theory with Cauchy integral formula. The BIE is used to calculate the curvatures and moments on the boundaries directly. Numerical examples are given for orthotropic and isotropic plates with circular or elliptic holes under uniform bending and twisting moments. Comparison of the numerical results with the analytic solution for one hole shows that in general BIE can achieve higher accuracies in evaluating moments while BIEs and FEM have comparable accuracies for computing deflections.
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Shih, Tzu-Hsien, and 石子賢. "Effects of Different Semi-Elliptical Bolt Holes on the Stress Concentration of Tensile Wooden Members." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/38273044366339721678.

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碩士
國立臺灣大學
森林環境暨資源學研究所
98
Generally, the tensile strength of wood is larger than that of compression strength in longitudinal direction. Because wood tissue could be damaged by metal connector or fastener, stress concentration always occurred at wood near the interface between wood and metal. This is the reason why the tensile strength value is almost close to or even lower than compression value in structural design. In previous reviews, pioneers usually solved many problems by finite element analysis (FEA) simulation and assumed that the wood was isotropic. However, the wood is a kind of anisotropic material rather than isotropic. In fact, it is orthotropic. In this study, a software called Solid Works2008 was used to find the results by FEA. The computer simulation is a tool that an assumed force can apply on a new type of bolt connection in order to reduce stress concentration. Douglas fir (Pseudotsuga menziesii) was selected as the wood member. The material of the bolt was common steel. In this computer simulation, steel was set as an isotropic material. In Cartesian coordinate, the x-direction was assumed in longitudinal direction of the wood. The y- and z-direction represented radial and tangential directions of the wood respectively. The total length of the member is 250 mm, and the width and the thickness are 60 and 12 mm. The hole is drilled in the central. The right side of the hole is a semicircle with 9.5 mm radius a, and the left side is a semiellipse with b mm semimajor axis (or with semiminor axis, if b&lt;a). All the initial sizes are constant, but the length of the semi axis of the semiellipse is variable, so that the definition of the axis ratio R is b/a, where a is the radius of the semicircle. R is set starting from 0.75, and each model with an increment of 0.25 for R was built and analyzed. The applied load was a concentrated force of 980.67 N（100 kgf） on the metal bolt towards the left. The right side of the member would be fixed and could not be moved and there was no deformation or displacement at the end surface. The interface between the wood and the metal bolt was set to free. There was neither glue nor adhesive between them, so there was a clearance while the deformation and displacement happened. Friction was neglected, however. Compared with simulation results, it is evident that the distribution of stress is quite different between isotropic and orthotropic member. But stress concentration still exists in both models at same locations. To enhance the utilization of wood material, the good property of tensile strength of wood should be considered. But stress concentration around the hole will reduce this property. Adjusting the ratio of the axes of R can find a way to reduce the stress concentration. One of the concentrated stresses must be increased while another must be decreased whether the ratio increases or decreases. The simulation show that a good result can be obtained when the ratio R is about 1.2 to 1.25. In the experiment, strain gauges and the universal testing machine were used. Signals were measured and converted through the written computer program. Basically, some of the results are similar with computer simulations. While the applied load is constant, the value of strain at the tensile area by the bolt hole decreases with R increasing, and the value of strain at the compression area by the bolt hole increases with R increasing. However, there were some disadvantages for mechanism such as nodes of wood, grain. And the dimension of the models was too small (limited by the testing machine) that the disadvantages appeared obviously. Because of the small dimension, the scale of strain gauges was enlarged, so that a part of the results were not so accuracy.
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Wager, David. "The Influence of Elliptical Nozzle Holes on Mixing and Combustion in Direct Injection Natural Gas Engines." Thesis, 2008. http://hdl.handle.net/1807/17235.

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Experiments were conducted to compare mixing and combustion of natural gas jets from round and elliptical nozzle holes in an optically accessible combustion bomb. A flame ionization detector was used to measure the concentration fields of the two jet types. Pressure data, combustion imaging, and hydrocarbon measurements of exhaust gas were used to compare the ignition delay, heat release, and combustion efficiency of the two nozzles. Concentration measurements indicated that the elliptical nozzle produced jets with smaller rich core regions and lower peak concentrations at all conditions. Firing tests indicated that the two nozzles produced equivalent ignition delays. Peak heat release rates were higher for the round nozzle, while the elliptical nozzle produced smoother transitions from premixed to diffusion burning. Combustion efficiency was slightly higher for the round nozzle. Results indicate that elliptical nozzles could potentially lower NOx and particulate emissions, but further experiments are required to test this hypothesis.
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Habbaky, Charles. "A Comparative Study between Circular and Elliptical Nozzle Holes on Natural Gas Combustion and Soot Formation in a Direct Injection Engine." Thesis, 2012. http://hdl.handle.net/1807/33230.

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The effects of changing nozzle hole patterns and hole geometry in a direct injection natural gas optically accessible engine was investigated. Six nozzles were studied having a 1 hole, 3 hole, and 9 hole pattern; each having either elliptical or circular hole geometries. Combustion images were taken with a high speed camera and the nozzles were compared on the basis of their ignition delay time, rate of heat release, net heat release, fuel utilization, gross indicated thermal efficiency, and particulate emissions. The best performance in all categories was achieved by the 9 hole nozzles which was largely attributed to better fuel mixing as a result of its hole distribution. The elliptical hole geometry exhibited characteristics of improved mixing mainly through reduced ignition delay time and reduced elemental carbon emissions.
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Glass, Lisa Anne. "The Central regions of early-type galaxies in nearby clusters." Thesis, 2012. http://hdl.handle.net/1828/4188.

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Remarkably, the central regions of galaxies are very important in shaping and influencing galaxies as a whole. As such, galaxy cores can be used for classification, to determine which processes may be important in galaxy formation and evolution. Past studies, for example, have found a dichotomy in the inner slopes of early-type galaxy surface brightness profiles. Using deprojections of the galaxies from the ACS Virgo and Fornax Cluster Surveys (ACSVCS/FCS), we show that, in fact, this dichotomy does not exist. Instead, we demonstrate that the brightest early-type galaxies tend to have central light deficits, a trend which gradually transitions to central light excesses – also known as compact stellar nuclei – as we go to fainter galaxies. This effect is quantified, and can be used to determine what evolutionary factors are important as we move along the galaxy luminosity function. The number of stellar nuclei that we observe is, in fact, an unexpected result emerging from the ACSVCS/FCS. Being three times more common than previously thought, they are present in the vast majority of intermediate and low-luminosity galaxies. Conversely, it has been known for over a decade that there is likely a supermassive black hole weighing millions to billions of solar masses at the center of virtually every galaxy of sufficient size. These black holes are known to follow scaling relations with their host galaxies. Using the ACSVCS, along with new kinematical data from long-slit spectroscopy, we measure the dynamical masses of 83 galaxies, and show that supermassive black holes and nuclei appear to fall along the same scaling relation with host mass. Both represent approximately 0.2% of their host’s mass, implying an important link between the two types of central massive objects. Finally, we extract elliptical isophotes and fit parameterized models to the surface brightness profiles of new Hubble Space Telescope imaging of the ACSVCS galaxies, observed in infrared and ultraviolet bandpasses. Taken together, the two surveys represent an unprecedented collection of isophotal and structural parameters of early-type galaxies, and will allow us to learn a great deal about the stellar populations and formation histories of galaxy cores.
Graduate
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Books on the topic "Elliptical holes"

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Southin, Justine Clair. Massive black holes in the centres of elliptical galaxies. Birmingham: University of Birmingham, 1999.

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P, Minicozzi William, ed. A course in minimal surfaces. Providence, R.I: American Mathematical Society, 2011.

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Book chapters on the topic "Elliptical holes"

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De Zeeuw, P. T. "Central Black Holes and Dark Halos in Elliptical Galaxies." In Stellar Populations, 215–25. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0125-7_20.

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Thomas, Jens. "Schwarzschild Modelling of Elliptical Galaxies and Their Black Holes." In Reviews in Modern Astronomy, 143–54. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2011. http://dx.doi.org/10.1002/9783527634842.ch8.

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Lin, Jia-Keng, and Charles E. S. Ueng. "Stress Concentrations in Orthotropic Laminates Containing Two Elliptical Holes." In Composite Structures 4, 419–30. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3457-3_32.

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Jiakeng, Lin, and Wang Linjiang. "Stress Concentration in a Finite Width Laminate Containing Several Elliptical Holes." In Composite Structures 5, 689–700. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-1125-3_42.

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Churazov, E., S. Sazonov, R. Sunyaev, W. Forman, C. Jones, and H. Böhringer. "Supermassive Black Holes in Elliptical Galaxies: Switching from Very Bright to Very Dim." In ESO Astrophysics Symposia, 295–99. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-74713-0_67.

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Khechai, Abdelhak, Abdelouahab Tati, Mohamed Ouejdi Belarbi, and Abdelhamid Guettala. "Finite Element Analysis of Stress Concentrations in Isotropic and Composite Plates with Elliptical Holes." In Design and Modeling of Mechanical Systems - II, 427–36. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-17527-0_43.

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Zhang, Yani. "High-Nonlinearity Negative Dispersion Effect of Crystal Fiber with Elliptical Holes Square-Mesh Cladding." In Lecture Notes in Electrical Engineering, 623–29. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-21747-0_79.

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Craciun, Eduard-Marius. "Prestressed Orthotropic Material Containing an Elliptical Hole." In Advanced Structured Materials, 327–36. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-0959-4_18.

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Soni, Sandeep, and Udaykumar Saindane. "Stress Analysis of Infinite Plate with Elliptical Hole." In Lecture Notes in Mechanical Engineering, 535–45. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-6469-3_50.

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Gibbons, G. W. "The Elliptic Interpretation of Black Holes and Quantum Mechanics." In Particle Physics, 95–104. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4613-1877-4_5.

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Conference papers on the topic "Elliptical holes"

1

Khajehhasani, Siavash, and B. A. Jubran. "Film Cooling From Circular and Elliptical Exit Shaped Holes With Sister Hole Influence." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95138.

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In traditional film cooling configuration, coolant is injected through a cylindrical pipe with an inclined angle (0<α<90), which results in an elliptical exit shaped hole (EESH) at the blade surface. The present study makes use of an elliptical injection coolant pipe that leads to a circular exit shaped hole (CESH). The film cooling effectiveness and the associated flow for both cases of circular and elliptical shaped holes are numerically investigated. A comparison between the predicted results and the available experimental results from the literature for blowing ratios of M = 0.5 and 1, clearly indicated a better agreement with the experimental results when the realizable k-ε model was used. Further, the results indicate that the circular exit shaped hole improves the centerline and laterally averaged adiabatic effectiveness, particularly, at a higher bowing ratio of 1. The analysis of the vortex generation downstream of the jet for both exit shaped holes, shows a considerable decrease in the jet lift-off where the coolant flow tends to adhere more to the surface and hence, provides a better film cooling protection for the circular exit shaped hole, in comparison with the common elliptical exit shaped hole. The influence of sister holes on film cooling performance tends to be more effective with circular exit shaped hole than that with elliptical exit shaped hole.
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Szarniak, Przemyslaw, Ryszard Buczynski, Dariusz Pysz, Ireneusz Kujawa, Marcin Franczyk, and Ryszard Stepien. "Highly birefringent photonic crystal fibers with elliptical holes." In Congress on Optics and Optoelectronics, edited by Waclaw Urbanczyk, Bozena Jaskorzynska, and Philip S. J. Russell. SPIE, 2005. http://dx.doi.org/10.1117/12.623045.

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Aluko, O., and H. A. Whitworth. "Contact Stress Analysis Around Elliptic Pin-Loaded Holes in Orthotropic Plates." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-37662.

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This analysis utilizes the complex stress function approach to obtain the stress distribution in pin loaded composite joints with elliptic openings. The stress functions were derived from assumed displacement expressions that satisfy the boundary conditions around the hole. In the method of solution Coulomb friction was used to determine the prescribed displacements at the boundary. The material properties of graphite/epoxy and carbon fiber reinforced plastics laminates were used in this investigation and the results also compared with available data for joints with circular openings. It was revealed that the stress distributions followed the same pattern in both geometries but with lower magnitude in elliptical shape and the reduction in stress distributions caused by changing the pin/hole shape from circular to elliptic depend on friction.
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Kujawa, Ireneusz, Ryszard Buczynski, Dariusz Pysz, Tadeusz Martynkien, Tomasz Nasilowski, Hugo Thienpont, and Ryszard Stepien. "Silicate photonic crystal fibers with rectangular lattice and elliptical holes." In International Congress on Optics and Optoelectronics, edited by Kyriacos Kalli. SPIE, 2007. http://dx.doi.org/10.1117/12.723455.

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Li, Jinjin, Xin Yan, and Kun He. "Effect of Non-Axisymmetric Endwall Profiling on Heat Transfer and Film Cooling Effectiveness of a Transonic Rotor Blade." In ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-90154.

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Abstract Effects of non-axisymmetric endwall profiling on total pressure loss, heat transfer and film cooling effectiveness of a transonic rotor blade were numerically investigated. The numerical methods, including the turbulence model and grid sensitivity, were validated with the existing experimental data. To reduce thermal load on endwall, non-axisymmetric endwall profiling near leading edge and at pressure-side corner area were performed with a range of contour amplitudes. Heat transfer and flow fields near the profiled endwalls were analyzed and also compared to the plain endwall configuration. On the profiled endwall, three kinds of cooling-holes, i.e. cylindrical holes, rounded-rectangular holes and elliptical holes, were arranged, and film cooling effect was investigated at three blowing ratios. Results indicate that, with endwall profiling, the area-averaged Stanton number on endwall is reduced by 7.71% and total pressure loss in cascade is reduced by 11.07%. Among three kinds of cooling holes, arrangement of elliptical hole performs the best film cooling effect on profiled endwall. Compared with plain endwall, non-axisymmetric endwall with elliptical cooling holes improves film cooling coverage by 10.87%, reduces the Stanton number by 8.88% and increases the net heat flux reduction performance by 4% at M = 0.7.
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Xiao, Kun, Juan He, and Zhenping Feng. "Film Cooling Effectiveness Enhancement Using Multi-Longitudinal Vortex Generated by Alternating Elliptical Film Holes." In ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/gt2021-58451.

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Abstract This paper proposed an alternating elliptical film hole for gas turbine blade to restrain kidney vortex and enhance film cooling effectiveness, based on the multi-longitudinal vortexes generated in alternating elliptical tube. The detailed flow structures in film hole delivering tube and out of the film hole, adiabatic film cooling effectiveness distributions as well as the total pressure loss coefficient were investigated. The delivering tube of alternating elliptical film hole consists of two straight sections and a transition section. In the straight sections, the cross section of the film hole is elliptical, and in the transition section, along flow direction, the major axis gradually shortened into the minor axis, and the minor axis gradually expanded to the major axis. But, the cross-section area of the film hole kept constant. Numerical simulations were performed by using 3D steady flow solver of Reynolds-averaged Navier-Stokes equations (RANS) with the SST k-ω turbulence model. To reveal the mechanism of kidney vortex suppression and film cooling effectiveness enhancement, the simulation results were compared with the cylindrical film hole set as the baseline at different mass flow ratios (MFR). Besides, the aerodynamic characteristics of these two kinds of film holes were also investigated. The results showed that obvious jet effect could be found in the cylindrical film hole, and the coolant mainly flowed along the upper wind wall, then interacted with the main flow, forming a strong kidney vortex after flowing out, which made the coolant to lift away from the wall surface and reduced the cooling effectiveness. The alternating elliptical film hole had a good inhibition impact on the jet effect in the hole due to the longitudinal vortices, which made the film adhere to the wall surface better after the coolant flowed out. The longitudinal vortices generated by alternating elliptical film hole have the opposite rotation direction to the vorticity of the kidney vortices, thus the kidney vortices were restrained to a certain extent. The height of kidney vortices is lower, and the size of kidney vortices is also smaller. As a result, the film cooling effectiveness of alternating elliptical film hole is distinctly higher than that of the cylindrical film hole, and the enhancement effect is more significant at higher mass flow ratio. In addition, the total pressure loss coefficient of alternating elliptical film hole is only slightly higher than the cylindrical film hole at the mass flow ratio of 1%, 2% and 3%, and is even lower at the mass flow ratio of 4%, thus inducing an excellent comprehensive performance.
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Aluko, O., and H. A. Whitworth. "Bearing Strength Analysis of Pin-Loaded Elliptical Holes in Laminated Composite Joints." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62507.

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An analysis was performed to predict bearing strength and mode of failure of pin loaded orthotropic plates with elliptic holes of varying sizes using two dimensional stress analyses and a characteristic curve model. The stresses required to analyze joint failure were obtained by utilizing complex stress functions that were determined from assumed displacement expressions that satisfy the boundary conditions around the hole. Three different joint geometries with major-to-minor diameter ratios ranging from 1 to 5 were evaluated and the analysis revealed that the joint strength was found to vary with increasing major-to-minor diameter ratios. The material properties of graphite/epoxy laminates were used in this investigation.
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Zaineb, Gharsallah, Monia Najjar, and Vijay Janyani. "Slow light optimization in symmetric photonic crystal waveguide with elliptical holes." In 2016 22nd Asia-Pacific Conference on Communications (APCC). IEEE, 2016. http://dx.doi.org/10.1109/apcc.2016.7581469.

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Wang, Fanghua, Jing Ma, and Chun Jiang. "Dispersionless slow wave of photonic crystal slab with elliptical air holes." In 2007 International Nano-Optoelectronics Workshop. IEEE, 2007. http://dx.doi.org/10.1109/inow.2007.4302915.

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Song, Peng, Yanrong Tong, and Xinlian Chen. "A novel high birefringence photonic crystal fiber with squeezed elliptical holes." In 2010 3rd International Conference on Biomedical Engineering and Informatics (BMEI). IEEE, 2010. http://dx.doi.org/10.1109/bmei.2010.5639896.

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