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Journal articles on the topic 'Elliptical holes'

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Published: 4 June 2021
Last updated: 7 February 2022

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1

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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2

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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3

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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4

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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5

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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6

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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7

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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8

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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9

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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10

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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11

Shragge, Jeffrey. "Elliptical moveout operator for data regularization in azimuthally anisotropic media." GEOPHYSICS 78, no. 1 (January 1, 2013): C1—C10. http://dx.doi.org/10.1190/geo2012-0227.1.

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Data regularization by azimuthal moveout (AMO) is an important seismic processing step applied to minimize the deleterious effects of irregular and incomplete acquisition in complex geology. Using isotropic AMO operators on data acquired over azimuthally anisotropic media, though, can lead to poor regularization results due to mixing of wavefield information from neighboring traces with azimuthally varying velocity profiles. An elliptical moveout operator (EMO), representing an extension of isotropic AMO to elliptical azimuthally anisotropic media, is sensitive to variations in the magnitude and the orientation of velocity ellipticity. AMO and EMO operators can be applied to regularize data by moving wavefield information from traces acquired at neighboring offsets and midpoints to infill existing data holes. Unlike AMO, though, EMO operators also can be used in a data conditioning procedure to interpolate energy between seismic traces where input and output velocity profiles are azimuthally elliptical and isotropic, respectively. Resulting processed data volumes are approximately free of elliptical azimuthal anisotropy, as can be shown by comparing analytical traveltimes and numerically calculated wavefield arrivals. EMO thus represents a one-step regularization/conditioning procedure for elliptically azimuthally anisotropic media that is more consistent with wave-equation physics and yields more accurate results than when compared with those from isotropic processing and elliptical residual moveout operator static corrections.
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12

Ukadgaonker, V. G., and D. B. Patil. "Stress Analysis of a Plate Containing Two Elliptical Holes Subjected to Uniform Pressures and Tangential Stresses on Hole Boundaries." Journal of Engineering for Industry 115, no. 1 (February 1, 1993): 93–101. http://dx.doi.org/10.1115/1.2901644.

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In this paper an elastostatic problem of two unequal elliptical holes subjected to internal pressures and shears are solved using the Kolosoff-Muskhelishvili stress functions, and the Schwarz alternating method of successive relaxation for multiply connected regions. Various stress concentration factors are obtained by changing the sizes of the two holes, the center distances, and the stress ratios on the two holes.
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13

Wang, Ailun, Chongmin She, Gang Lin, You Zhou, and Wanlin Guo. "Stress intensity factors for part-elliptical cracks emanating from dimpled rivet holes." International Journal of Computational Materials Science and Engineering 03, no. 04 (December 2014): 1450022. http://dx.doi.org/10.1142/s2047684114500225.

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Detailed investigations on the stress intensity factors (SIFs) for corner cracks emanated from interference fitted dimpled rivet holes are conducted using three-dimensional finite element method. The influences of the crack length a, elliptical shape factor t, far-end stress S and interference magnitude δ on the stress intensity factors are systematically studied. The SIFs for corner cracks emanated from open holes are also investigated for comparisons. An empirical formula of the normalized SIF is proposed by use of the least square method for convenience of the engineering application, which is a function of the crack length a, elliptical shape factor t, far-end stress S, interference magnitude δ and the normalized elliptical centrifugal angle φn. Based on the empirical formula, a crack growth simulation for a rivet filled hole is conducted, which shows a good agreement with the test data.
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14

de Zeeuw, P. T., and C. M. Carollo. "Dynamical Constraints on the Formation of Elliptical Galaxies." Symposium - International Astronomical Union 171 (1996): 47–54. http://dx.doi.org/10.1017/s0074180900232142.

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Recent work on the construction of spherical, axisymmetric and triaxial dynamical models for elliptical galaxies is reviewed briefly, including their role in providing evidence for dark halos and central black holes. The different orbital structures and shapes of low-mass and giant elliptical galaxies provide essential constraints on scenarios of galaxy formation.
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15

Huang, You Qian, Wan Zhen Wang, Wei Tao Wang, and Ke Ting Tong. "Fracture Mechanism and Ductility Construction of Joints of H-Style Beam-Square Tubular Column." Advanced Materials Research 446-449 (January 2012): 484–89. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.484.

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Numerical simulation and fracture analysis were performed on conventional joint of H-style beam-square steel tubular column based on suggested elliptical yield model. The modified coefficient of elliptical fracture model was obtained by equivalently calculating the effects of residual stress and flaws. Using the elliptical fracture model with equivalently calculating the effects of residual stress and disfigurement for evaluation, the parameters of slot holes and horizontal haunch at beam flanges on failure mode of joints of H-style steel beam-square steel tubular column were studied by finite element method. The results indicate that the plastic rotation of joints of H-style beam-square steel tubular column with slot holes and horizontal haunch at beam flanges reach 0.03rad and meet with the requirement of the interim guidelines FEMA, and the loading capacity decrease within 15% compared with that of the conventional joint.
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16

Troyani, Nando, and Milagros Sánchez. "Howland’s isotropic Kts curve for plates with circular holes as a master curve for Kts in orthotropic plates with elliptical holes." Journal of Strain Analysis for Engineering Design 52, no. 3 (February 6, 2017): 152–61. http://dx.doi.org/10.1177/0309324716689435.

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The importance of the role played by the so-called stress concentration factors (or symbolically referred to as Kts) in analysis and design in both mechanical and structural engineering is a well-established fact, and accuracy and ease in their estimation result in significant aspects related to engineering costs, and additionally on both the reliability in the design of parts and/or in the analysis of failed members. In this work, rectangular finite width plates of both isotropic and orthotropic materials with circular and elliptical holes are considered. Based on two key observations reported herein, it is shown in a partially heuristic engineering sense, that Howland’s solution curve for the stress concentration factors for finite width plates with circular holes subjected to tension can be viewed as a master curve; accordingly, it can be used as a basis to rather accurately estimate stress concentration factors for isotropic finite width tension rectangular plates with centered elliptical holes and also rather accurately used to estimate stress concentration factors for orthotropic finite width rectangular plates under tension with centered elliptical holes. Two novel concepts are defined and presented to this effect: geometric scaling and material scaling. In all the examined and reported cases, the specific numerical results can be obtained accurately using a hand-held calculator making virtually unnecessary the need to program and/or use other complex programs based on the finite element method, just as an example. The maximum recorded average error for all the considered cases being 2.62% as shown herein.
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17

Chau, Yuan-Fong, Gui-Min Lin, Chiung-Chou Liao, Shinn-Fwu Wang, and Jeng-Hua Wei. "Numerical Investigations on Birefringent Holey Fibers by Modified Elliptical Air Holes in Fiber Cladding." Japanese Journal of Applied Physics 50, no. 11R (November 1, 2011): 112502. http://dx.doi.org/10.7567/jjap.50.112502.

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18

Chau, Yuan-Fong, Gui-Min Lin, Chiung-Chou Liao, Shinn-Fwu Wang, and Jeng-Hua Wei. "Numerical Investigations on Birefringent Holey Fibers by Modified Elliptical Air Holes in Fiber Cladding." Japanese Journal of Applied Physics 50 (October 27, 2011): 112502. http://dx.doi.org/10.1143/jjap.50.112502.

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19

Jasiuk, I., J. Chen, and M. F. Thorpe. "Elastic Moduli of Two Dimensional Materials With Polygonal and Elliptical Holes." Applied Mechanics Reviews 47, no. 1S (January 1, 1994): S18—S28. http://dx.doi.org/10.1115/1.3122813.

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We study the effective elastic moduli of two-dimensional composite materials containing polygonal holes. In the analysis we use a complex variable method of elasticity involving a conformal transformation. Then we take a far field result and derive the effective elastic constants of composites with a dilute concentration of polygonal holes. In the discussion we use the recently-stated Cherkaev-Lurie-Milton theorem, which gives general relations between the effective elastic constants of two-dimensional composites. We also discuss known results for elliptical holes in the context of the present work.
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20

Wang, Jingyuan, Chun Jiang, Weisheng Hu, and Mingyi Gao. "High birefringence photonic bandgap fiber with elliptical air holes." Optical Fiber Technology 12, no. 3 (July 2006): 265–67. http://dx.doi.org/10.1016/j.yofte.2005.11.002.

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21

Hsieh, M. C., and Chyanbin Hwu. "Hygrothermal Stresses in Unsymmetric Laminates Disturbed by Elliptical Holes." Journal of Applied Mechanics 73, no. 2 (June 28, 2005): 228–39. http://dx.doi.org/10.1115/1.2074708.

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Since the composite laminates are now in widespread use, many coupling phenomena within the composite laminates are widely focused in the world. One of those is the problem of stretching-bending coupling under hygrothermal environment. Because of the hygrothermal stress concentration, the understanding of hygrothermal effects on holes in laminates becomes important for the practical engineering design. However, due to mathematical infeasibility, most of the analytical solutions presented in literature are for two-dimensional problems or just for mechanical loading conditions, not for general composite laminates under hygrothermal environment. In order to establish a systematic analytical approach, in this study by extending the Stroh formalism for two-dimensional linear anisotropic elasticity and the Stroh-like formalism for coupled stretching-bending analysis of composite laminates, we develop an extended Stroh-like formalism for the coupled stretching-bending analysis under hygrothermal environment. By using the extended Stroh-like formalism developed in this paper, the explicit solutions for an unbounded laminate, symmetric or unsymmetric, disturbed by an elliptical hole subjected to uniform heat flow and moisture transfer in the x1-x2 plane or x3 direction are now obtained. With these solutions three typical numerical examples are illustrated and compared by ANSYS finite element software package.
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22

Xu, X. W., H. C. Man, and T. M. Yue. "Strength prediction of composite laminates with multiple elliptical holes." International Journal of Solids and Structures 37, no. 21 (May 2000): 2887–900. http://dx.doi.org/10.1016/s0020-7683(99)00033-5.

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23

De Zeeuw, P. T. "Central Black Holes and Dark Halos in Elliptical Galaxies." Symposium - International Astronomical Union 164 (1995): 215–25. http://dx.doi.org/10.1017/s0074180900108599.

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Studies of the mass–to–light ratio M/L as a function of radius in a galaxy usually focus on: a) the existence of dark matter in and around galaxies, and b) the presence of massive black holes in their nuclei. Here we concentrate on elliptical galaxies, and summarize some recent work in both areas. We refer to more extensive reviews for earlier developments (Schwarzschild, 1954; Trimble, 1987; Ashman, 1992; Kormendy, 1993). A third area of interest is the behavior of the stellar populations as a function of radius, and its effect on M/L (e.g., Peletier, 1989). We will not discuss this here.
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24

Tsukrov, I., and M. Kachanov. "Stress concentrations and microfracturing patterns for interacting elliptical holes." International Journal of Fracture 68, no. 3 (1994): R89—R92. http://dx.doi.org/10.1007/bf00013078.

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25

Lin, Jia-Keng, and Charles E. S. Ueng. "Stresses in a laminated composite with two elliptical holes." Composite Structures 7, no. 1 (January 1987): 1–20. http://dx.doi.org/10.1016/0263-8223(87)90058-4.

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26

SILK, JOSEPH. "GALAXY FORMATION: THE FIRST 109 YEARS." Modern Physics Letters A 22, no. 25n28 (September 14, 2007): 1865–74. http://dx.doi.org/10.1142/s021773230702508x.

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Progress has been made in understanding the origin of spiral galaxies, but elliptical galaxy formation continues to pose many problems. At the centres of ellipticals, one finds supermassive black holes which are occasionally fed by gas accretion from their surroundings and are visible as active galactic nuclei. Negative feedback, due to the outflow from the central black hole during its active phase, terminates the gas supply to the spheroid, thereby resulting in an old stellar population. A contemporaneous phase of positive feedback when the protogalaxy is forming could result in the highly efficient phase of early star formation required by the recent data.
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27

Wang, Yang, Manchao He, Dongqiao Liu, and Yubing Gao. "Rockburst in Sandstone Containing Elliptic Holes with Varying Axial Ratios." Advances in Materials Science and Engineering 2019 (April 1, 2019): 1–17. http://dx.doi.org/10.1155/2019/5169618.

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Rockburst disaster is one of the prominent problems faced by deep underground engineering. In this study, rockburst in four elliptical holes with different axial ratios in sandstone under biaxial loading is studied as an analogue for underground roadways. Video and acoustic emission (AE) equipment is used to monitor the biaxial loading tests. Experimental results indicate that each of the elliptical holes goes through four stages: quiet period, small particle ejection, spalling, and rockburst. The duration of quiet and spalling periods increased with increasing axial ratio of ellipse. The duration of the ejection and rockburst periods remains unchanged. All the four elliptical holes have V-shaped pits after rockburst occurs. The fragments produced during rockburst are divided into coarse, medium, fine, and micro grains. The quantity of coarse and medium grains increases with increasing axial ratio. The mass ratio of coarse and medium grains increases and that of fine and micro grains decreases. The depth, angle, and area of the V-shaped pits decrease with increasing axis ratio. Tensile cracks play an important role in rockburst failure. Tensile cracks are the dominant crack types formed during rockburst and account for over 70% of all cracks in the samples. The number of tensile cracks increased and the number of shear cracks decreased. This paper has some reference value for practical engineering design and prevention of rockburst.
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28

Kim, Dong-Woo, and Silvia Pellegrini. "JD8 - Hot Interstellar Matter in Elliptical Galaxies." Proceedings of the International Astronomical Union 5, H15 (November 2009): 269–70. http://dx.doi.org/10.1017/s1743921310009154.

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The physical properties of the hot interstellar matter in elliptical galaxies are directly related with the formation and evolution of elliptical galaxies via star formation episodes, environmental effects such as stripping, infall, and mergers, and growth of super-massive black holes. The recent successful Chandra and XMM-Newton X-ray space missions have provided a large amount of high spatial/spectral resolution observational data on the hot ISM in elliptical galaxies. At the same time, theoretical studies with numerical simulations and analytical modeling of the dynamical and chemical evolution of elliptical galaxies have made a significant progress and start to predict various observable quantities.
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Wu, Bo, Shixiang Xu, Guowang Meng, Yaozhong Cui, Junhua Cai, and Yao Zhang. "Study on the Dynamic Evolution of Through-Crack in the Double Hole of Elliptical Bipolar Linear-Shaped Charge Blasting." Shock and Vibration 2021 (August 17, 2021): 1–7. http://dx.doi.org/10.1155/2021/3792765.

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Seeking the law of through-crack in the double hole of shaped charge can help reveal the rock failure mechanism of directional controlled blasting. Using LS-DYNA numerical simulation analysis, the dynamic mechanical behaviors of double-hole crack development and double-hole crack penetration in elliptical bipolar linear-shaped charge blasting and ordinary blasting were compared and studied. The results showed that it was difficult to form a straight line through the double holes under ordinary blasting, while easy to cause over-under-excavation problems. The blasting of the elliptical bipolar linear-shaped charge had a significant effect on the formation of directional crack. The crack penetrated along the connecting center line of the two holes. The main crack growth form was tensile fracture mode, and the explosion gas was the important driving force for continuous crack growth. The elliptical bipolar linear-shaped charge blasting produced fewer cracks in the nonenergy-accumulating direction, which could effectively reduce the damage of the retained rock mass.
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30

Liu, Fei, Hong Yan Gao, and Yu Qian. "Polarization Properties of Polymer Photonic Crystal Fiber with Square-Lattice Elliptical Air-Hole." Advanced Materials Research 631-632 (January 2013): 233–38. http://dx.doi.org/10.4028/www.scientific.net/amr.631-632.233.

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A novel type of photonic crystal fiber for high birefringence and zero-walkoff is proposed based on polymer, the fiber is composed of a solid polymer core and a cladding with square lattice elliptical air-holes along the fiber length. The optical birefringence and polarization-dependent leakage loss are studied numerically based on the full-vector finite element method(FEM). Numerical results show that the proposed fiber has heightened modal birefringence of the order of 10-2; and the leakage loss is reduced to 0.08dB/m at wavelength of 0.65μm when it has 10 rings of elliptical air-holes. So the proposed PCFs may be useful in the field of high birefringence polarization-maintaining optical communication.
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31

Omirou, Sotiris L., and Marios M. Fyrillas. "New CNC Programming Functions Based on Elliptical Motion." Journal for Manufacturing Science & Production 13, no. 3 (October 25, 2013): 155–64. http://dx.doi.org/10.1515/jmsp-2012-0041.

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AbstractThis paper proposes a set of four elliptical features that can enhance the programming capabilities of a modern CNC system. Namely, a real-time interpolation algorithm for motion generation along an ellipse and its offset, machining of an elliptical pocket, and drilling a series of equidistant holes along an elliptical path. The paper analytically describes the implementation of the new functions while the G-codes, along with their complementary requisite data needed to be introduced in the CNC part program, are exemplified with simulation and actual machining tests for each feature.
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32

Gao, Nan, Jian Li, Rong-hao Bao, and Wei-qiu Chen. "Harnessing uniaxial tension to tune Poisson's ratio and wave propagation in soft porous phononic crystals: an experimental study." Soft Matter 15, no. 14 (2019): 2921–27. http://dx.doi.org/10.1039/c8sm02468e.

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33

Tahat, Montasser, Salih Akour, Saad Habali, and Jamal Nayfeh. "Optimization of Defense Hole System for Biaxial Loaded Plate with Three Coaxial Holes." Advances in Structural Engineering 8, no. 2 (April 2005): 117–28. http://dx.doi.org/10.1260/1369433054038001.

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Optimum design of elliptical Defense Hole System (DHS) under biaxial loading in a finite plate with a row of circular holes is presented. Maximum stress reduction is made possible by introducing elliptical auxiliary holes close to the mainmain holes in the areas of low stresses along the principal stress direction. A systematic study is undertaken by using the finite element analysis (FEA) to determine the optimum shape, location and size of the auxiliary defense hole system. These parameters are examined in relation to plate dimensions for a number of plates with different mainmain-hole-diameter to plate-width ratios and different pitch to main-hole-diameter ratios. Maximum stress reductions from 6–18% were achieved. With such reduction in the maximum stress level the improvement in fatigue life of a structural part can be very significant. The FEA results are validated experimentally by applying an enhanced RGB-photoelasticity technique. The photoelasticity experimental results and the FEA results show good agreement.
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34

Correa, Camila A., and Joop Schaye. "The dependence of the galaxy stellar-to-halo mass relation on galaxy morphology." Monthly Notices of the Royal Astronomical Society 499, no. 3 (October 7, 2020): 3578–93. http://dx.doi.org/10.1093/mnras/staa3053.

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ABSTRACT We investigate the dependence of the local galaxy stellar-to-halo mass relation (SHMR) on galaxy morphology. We use data from the Sloan Digital Sky Survey (SDSS) data release 7 with morphological classifications from Galaxy Zoo, and compare with the EAGLE cosmological simulation. At fixed halo mass in the mass range $10^{11.7}\!-\!10^{12.9}\, {\rm M_{\odot }}$, the median stellar masses of SDSS disc galaxies are up to a factor of 1.4 higher than the median masses of their elliptical counterparts. However, when we switch from the stellar masses from Kauffmann et al. to those calculated by Chang et al. or Brinchmann et al., the median SHMR from discs and ellipticals coincides in this mass range. For halo masses larger than $10^{13}\, {\rm M_{\odot }}$, discs are less massive than ellipticals in same-mass haloes, regardless of whose stellar mass estimates we use. However, we find that for these high halo masses the results for discs may be affected by central/satellite misclassifications. The EAGLE simulation predicts that discs are up to a factor of 1.5 more massive than elliptical galaxies residing in same-mass haloes less massive than $10^{13}\, {\rm M_{\odot }}$, in agreement with the Kauffmann et al. data. Haloes with masses between 1011.5 and $10^{12}\, {\rm M_{\odot }}$, which host disc galaxies, were assembled earlier than those hosting ellipticals. This suggests that the discs are more massive because they had more time for gas accretion and star formation. In $10^{12}\!-\!10^{12.5}\, {\rm M_{\odot }}$ haloes, the central black holes in elliptical galaxies grew faster and became more massive than their counterparts in disc galaxies. This suggests that in this halo mass range the ellipticals are less massive because active galactic nucleus feedback ejected more of the halo’s gas reservoir, reducing star formation, and suppressing the (re)growth of stellar discs.
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35

Chau, Yuan-Fong, Han-Hsuan Yeh, and Din Ping Tsai. "Analysis of High Birefringence of Four Types of Photonic Crystal Fiber by Combining Circular and Elliptical Air Holes in Fiber Cladding." Advances in Nonlinear Optics 2008 (2008): 1–6. http://dx.doi.org/10.1155/2008/239037.

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This paper presents a numerical study of high birefringence induced by four types (Type 1–4) of different sizes of elliptical air holes in photonic crystal fibers (PCFs). The numerical simulation is carried out by using the finite element method. The statistical correlations between the birefringence and the various parameters are obtained. Based on our results, the birefringence is found to be largely dependent on the variation of the normalized frequency, size ratio, effective area of the circular and elliptical air holes, and the ring number of cladding. Two of our suggested structures, Type 1 and Type 3, can considerably enhance the birefringence in PCFs leading to values as high as7.697×10−3and8.002×10−3, respectively, which are much higher than that obtained by a conventional step-index fiber.
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36

Khaja, A. A., and R. E. Rowlands. "Experimentally Determined Stresses Associated with Elliptical Holes Using Polar Coordinates." Strain 49, no. 2 (March 21, 2013): 116–24. http://dx.doi.org/10.1111/str.12018.

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37

HEWIDY, M. "FURTHER PROBLEMS AFFECTING THE PRODUCTION OF ELLIPTICAL HOLES BY ECM." International Conference on Aerospace Sciences and Aviation Technology 1, CONFERENCE (May 1, 1985): 1–12. http://dx.doi.org/10.21608/asat.1985.26555.

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38

Lubarda, Vlado A. "On the circumferential shear stress around circular and elliptical holes." Archive of Applied Mechanics 85, no. 2 (September 13, 2014): 223–35. http://dx.doi.org/10.1007/s00419-014-0915-1.

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39

Alex-Amor, Antonio, Fatemeh Ghasemifard, Guido Valerio, Mahsa Ebrahimpouri, Pablo Padilla, Jose Manuel Fernandez Gonzalez, and Oscar Quevedo-Teruel. "Glide-Symmetric Metallic Structures With Elliptical Holes for Lens Compression." IEEE Transactions on Microwave Theory and Techniques 68, no. 10 (October 2020): 4236–48. http://dx.doi.org/10.1109/tmtt.2020.3011004.

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40

Wang, J. T., C. G. Lotts, and D. D. Davis. "Analysis of Bolt-Loaded Elliptical Holes in Laminated Composite Joints." Journal of Reinforced Plastics and Composites 12, no. 2 (February 1993): 128–38. http://dx.doi.org/10.1177/073168449301200201.

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41

Pipino, Antonio, Joseph Silk, and Francesca Matteucci. "Supermassive black holes, star formation and downsizing of elliptical galaxies." Monthly Notices of the Royal Astronomical Society 392, no. 1 (January 1, 2009): 475–82. http://dx.doi.org/10.1111/j.1365-2966.2008.14077.x.

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42

Issa, Nader A., Martijn A. van Eijkelenborg, Matthew Fellew, Felicity Cox, Geoff Henry, and Maryanne C. J. Large. "Fabrication and study of microstructured optical fibers with elliptical holes." Optics Letters 29, no. 12 (June 15, 2004): 1336. http://dx.doi.org/10.1364/ol.29.001336.

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43

Deng, Jie, Ling Zheng, and Oriol Guasch. "Elliptical acoustic black holes for flexural wave lensing in plates." Applied Acoustics 174 (March 2021): 107744. http://dx.doi.org/10.1016/j.apacoust.2020.107744.

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44

Bagal, Vikramsinh P., and Dr V. G. Arajpure. "Effect of elliptical holes on vibration characteristics of circular discs." INTERNATIONAL JOURNAL OF RECENT TRENDS IN ENGINEERING & RESEARCH 6, no. 5 (May 31, 2020): 52–65. http://dx.doi.org/10.23883/ijrter.2020.6031.k4wiu.

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45

Akour, S. N., J. F. Nayfeh, and D. W. Nicholson. "Design of a defence hole system for a shear-loaded plate." Journal of Strain Analysis for Engineering Design 38, no. 6 (August 1, 2003): 507–17. http://dx.doi.org/10.1243/030932403770735872.

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Stress concentrations associated with circular holes in pure shear-loaded plates can be reduced by up to 13.5 per cent by introducing elliptical auxiliary holes along the principal stress directions. These holes are introduced in the areas of low stresses near the main circular hole in order to smooth the principal stress trajectories. A systematic study based on univariate search optimization method is undertaken by using finite element analysis (FEA) to determine the optimum size and location for an auxiliary defence hole system. The results are validated using RGB (red-green-blue) photoelasticity.
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46

Hasebe, Norio, Mikiya Okumura, and Takuji Nakamura. "Bonded Bi-material Half-Planes With Semi-elliptical Notch Under Tension Along the Interface." Journal of Applied Mechanics 59, no. 1 (March 1, 1992): 77–83. http://dx.doi.org/10.1115/1.2899467.

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A problem of two bonded, dissimilar half-planes containing an elliptical hole on the interface is solved. The external load is uniform tension parallel to the interface. A rational mapping function and complex stress functions are used and an analytical solution is obtained. Stress distributions are shown. Stress concentration factors are also obtained for arbitrary lengths of debonding and for several material constants. In addition, an approximate expression of the stress concentration factor is given for elliptical holes and the accuracy is investigated.
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Yan, Xiangqiao. "Microdefect interacting with a finite main crack." Journal of Strain Analysis for Engineering Design 40, no. 5 (July 1, 2005): 421–30. http://dx.doi.org/10.1243/030932405x16089.

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This paper deals with the microdefect-finite main crack linear elastic interaction by means of a displacement discontinuity method with crack-tip elements. It consists of the non-singular displacement discontinuity element presented by Crouch and Starfield and the crack-tip displacement discontinuity elements presented by the author. Two models are used: one is ‘a finite main crack interaction with a collinear elliptical microdefect (hole)’ in an infinite medium; the other is ‘a finite main crack interaction with a pair of symmetric collinear elliptical microdefects (holes)’ in an infinite medium. In numerical computations, the ratio of the elliptical horizontal axis length to the main crack length is varied from 0.05 to 0.4 and the elliptical aspect ratio is taken as 0.0, 0.5, and 1.0. Thus, the present numerical results reveal the effect that the relative size of the elliptical microdefect (hole) to the main crack has on the microdefect-finite main crack interaction.
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48

Wang, Wei, Bo Yang, Yue Fan, and Hong Ru Song. "Characteristics Analysis of Photonic Crystal Fiber with Hexagonal and Octagonal Structure." Applied Mechanics and Materials 148-149 (December 2011): 326–30. http://dx.doi.org/10.4028/www.scientific.net/amm.148-149.326.

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Aiming at the requirements of high performance of optical communication systems, a new type of photonic crystal fiber (PCF) is proposed. This kind of PCF consists of hexagonal air holes in the inner cladding and octagonal air holes in the others layers. Two big elliptical air holes are embedded to enhance the birefringence. Numeral results show that this kind of PCF exhibits high birefringence with the level of 10-3 and high nonlinearity with the level of 10-2m-1w-1. In addition, two zero dispersion points are obtained after optimization, which will find application in dispersion compensation PCFs.
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Senthil Kumar, Mouleeswaran, M. Santhosh, E. Arvind, M. Ashwin, and S. Prashant. "Optimization of Spur Gear Design to Reduce Stress." Applied Mechanics and Materials 867 (July 2017): 220–27. http://dx.doi.org/10.4028/www.scientific.net/amm.867.220.

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The objective of the study is to reduce the stress created in the root fillet region as the maximum stress concentration in gears occurs in the fillet. Therefore, stress relieving features have been created at an offset distance from the root fillet to reduce the stress. A Spur gear with involute profile is taken for the study. The application taken for the study is the gear used in terrain vehicles. The material of the gear is EN-353 grade Steel. Based on the compressive strengths and bending strengths, the spur gear is designed to the required application. The gear is modelled using the specifications obtained from the design calculations. The forces acting on the gear is calculated considering the application in which it is used. The gear is then analysed using the ANSYS WORKBENCH 14.0 software. It has been found that the maximum stress acts near the root fillet region. Hence, stress relieving features of circular and elliptical shapes are created at an offset distance from the root fillet. It has been found that the gear with elliptical stress relieving hole has the minimum stress than those of gears with other combinations. The next objective which is to reduce the mass of the gear is done by creating larger holes in the lower stress regions of the gear. The mass reducing features are created in the gears with stress relieving features and each gear has been subjected to analysis for the minimum amount of stress. It has been found that the value of stress is less in the gear with mass reducing holes but with no stress relieving feature. Thus, the stress acting on the root fillet region has been reduced by 20% by creating circular and elliptical holes. The other objective of mass reduction is satisfied by creating larger holes.
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Matteo, T. Di, and S. W. Allen. "X-ray Emission from Supermassive Black Holes in Elliptical Galaxies and Low Radiative-efficiency Accretion." Symposium - International Astronomical Union 195 (2000): 387–88. http://dx.doi.org/10.1017/s0074180900163211.

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We discuss the detection of hard, power-law emission components in the X-ray spectra of six nearby, giant elliptical galaxies observed with the ASCA satellite and its implication for low-radiative efficiency accretion models around the central, supermassive black holes.
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