Unique operations for a highly inclined, elliptical, geosynchronous satellite
Anglin, Patrick T.; Briskman, Robert D.
2004-08-01
The first space segment devoted to a Digital Audio Radio Service (DARS) for the Continental United States (CONUS) was established when the last satellite of a three satellite constellation (Flight Models FM-1, FM-2 and FM-3) was launched in November 2000. Each satellite is in a highly inclined, elliptical, geosynchronous orbit that is separated by 120° in Right Angle of the Ascending Node (RAAN) from the other two satellites' orbits. This results in an 8 h phasing in ground track between each satellite. These distinct orbits provide superior look angles and signal availability to mobile receivers in the northern third of the United States when compared to geostationary satellites. However, this unique orbital constellation results in some particular performance and operational differences from geostationary orbit satellites. Some of these are: Earth Sensor noise, maneuver implementation and power management. Descriptions and performance improvements of these orbit specific operations are detailed herein.
Geosynchronous inclined orbits for high-latitude communications
Fantino, E.; Flores, R. M.; Di Carlo, M.; Di Salvo, A.; Cabot, E.
2017-11-01
We present and discuss a solution to the growing demand for satellite telecommunication coverage in the high-latitude geographical regions (beyond 55°N), where the signal from geostationary satellites is limited or unavailable. We focus on the dynamical issues associated to the design, the coverage, the maintenance and the disposal of a set of orbits selected for the purpose. Specifically, we identify a group of highly inclined, moderately eccentric geosynchronous orbits derived from the Tundra orbit (geosynchronous, eccentric and critically inclined). Continuous coverage can be guaranteed by a constellation of three satellites in equally spaced planes and suitably phased. By means of a high-precision model of the terrestrial gravity field and the relevant environmental perturbations, we study the evolution of these orbits. The effects of the different perturbations on the ground track (which is more important for coverage than the orbital elements themselves) are isolated and analyzed. The physical model and the numerical setup are optimized with respect to computing time and accuracy. We show that, in order to maintain the ground track unchanged, the key parameters are the orbital period and the argument of perigee. Furthermore, corrections to the right ascension of the ascending node are needed in order to preserve the relative orientation of the orbital planes. A station-keeping strategy that minimizes propellant consumption is then devised, and comparisons are made between the cost of a solution based on impulsive maneuvers and one with continuous thrust. Finally, the issue of end-of-life disposal is discussed.
Experimental studies on circular and AR4 elliptic vortex-ring impingement upon inclined surfaces
Shi, Shengxian; New, Tze How; Chen, Jian
2014-11-01
PLIF flow visualisation and TR-PIV measurements were performed on the impingement of circular and AR4 elliptic vortex-rings upon flat surface with different inclination angles at Re = 4000. This is aimed to investigate the effects of nozzle geometry, surface inclination angle and exit-surface separation distance on the vortex-ring impingement behaviour. Separation distance between nozzle exit and flat surface were adjusted for the elliptic vortex-ring so as to examine the flow structures for impingement prior, at and posterior the axis-switching point. Current results on circular vortex-ring show that at low inclination angle, vortex-ring underwent severe stretching during the impingement and vortex-ring core closer to the flat surface was observed to induce secondary vortex-ring and pair with it before its pinch-off. Meanwhile, vortex-ring core further away from the flat surface produced secondary and tertiary vortex-rings before transit into turbulence. At high inclination angles, vortex-ring core closer to the flat surface was quickly entrained by the primary vortex-ring after the impingement. Experiments on elliptic vortex-ring are undergoing at the moment, more findings will be presented in the conference.
Application of inclined elliptic orbits - A new dimension in satellite sound broadcasting
Galligan, K. P.; Robson, D.
1990-10-01
The communications link between a geostationary satellite and a mobile user operating in a high latitude region is subject to fading through a combination of shadowing and multipath effects. The properties of the link may be substantially improved by the use of satellites in highly inclined elliptic (HEO) orbits, with a resultant improvement in availability of the satellite service. Such systems have been under study in Europe for several years primarily in connection with voice communications. The application to a sound broadcasting satellite service is currently under investigation within the Archimedes program of the European Space Agency. The design principles of such systems are described and the performance parameters for both applications within the wider European context are indicated. Finally, an initial economic assessment of the HEO system in comparison with geostationary satellite and terrestrial based alternatives is provided.
Masago, Bruna Yukiko Pinheiro Lopes; Prado, Antonio Fernando Bertachini de Almeida; Chiaradia, Ana Paula Marins; Gomes, Vivian Martins
2016-02-01
Space missions to visit small bodies of the Solar System are important steps to improve our knowledge of the Solar System. Usually those bodies do not have well known characteristics, as their gravity field, which make the mission planning a difficult task. The present paper has the goal of studying orbits around the triple asteroid 2001SN263, a Near-Earth Asteroid (NEA). A mission to this system allows the exploration of three bodies in the same trip. The distances reached by the spacecraft from those three bodies have fundamental importance in the quality of their observations. Therefore, the present research has two main goals: (i) to develop a semi-analytical mathematical model, which is simple, but able to represent the main characteristics of that system; (ii) to use this model to find orbits for a spacecraft with the goal of remaining the maximum possible time near the three bodies of the system, without the need of space maneuvers. This model is called ;Precessing Inclined Bi-Elliptical Problem with Radiation Pressure; (PIBEPRP). The use of this model allow us to find important natural orbits for the exploration of one, two or even the three bodies of the system. These trajectories can be used individually or combined in two or more parts using orbital maneuvers.
Muliadi, J.; Jenie, S. D.; Budiyono, A.
2008-01-01
In response to the interest to re-use Palapa B2R satellite nearing its End of Life (EOL) time, an idea to incline the satellite orbit in order to cover a new region has emerged in the recent years. As a prolate dual-spin vehicle, Palapa B2R has to be stabilized against its internal energy dissipation effect. This work is focused on analyzing the dynamics of the reusable satellite in its inclined orbit. The study discusses in particular the stability of the prolate dual-spin satellite under th...
Rivera, Andrea
2016-01-01
From moving ramps to playground slides, inclined planes are at work all over in our world today. Learn all about them in five easy-to-read chapters. Vibrant, full-color photos, bolded glossary words, and a key stats section let readers zoom in even deeper. Aligned to Common Core Standards and correlated to state standards. Abdo Zoom is a division of ABDO.
Conjunction challenges of low-thrust geosynchronous debris removal maneuvers
Anderson, Paul V.; Schaub, Hanspeter
2016-06-01
The conjunction challenges of low-thrust engines for continuous thrust re-orbiting of geosynchronous (GEO) objects to super-synchronous disposal orbits are investigated, with applications to end-of-life mitigation and active debris removal (ADR) technologies. In particular, the low maneuverability of low-thrust systems renders collision avoidance a challenging task. This study investigates the number of conjunction events a low-thrust system could encounter with the current GEO debris population during a typical re-orbit to 300 km above the GEO ring. Sensitivities to thrust level and initial longitude and inclination are evaluated, and the impact of delaying the start time for a re-orbiting maneuver is assessed. Results demonstrate that the mean number of conjunctions increases hyperbolically as thrust level decreases, but timing the start of the maneuver appropriately can reduce the average conjunction rate when lower thrust levels are applied.
Shadow imaging of geosynchronous satellites
Douglas, Dennis Michael
Geosynchronous (GEO) satellites are essential for modern communication networks. If communication to a GEO satellite is lost and a malfunction occurs upon orbit insertion such as a solar panel not deploying there is no direct way to observe it from Earth. Due to the GEO orbit distance of ~36,000 km from Earth's surface, the Rayleigh criteria dictates that a 14 m telescope is required to conventionally image a satellite with spatial resolution down to 1 m using visible light. Furthermore, a telescope larger than 30 m is required under ideal conditions to obtain spatial resolution down to 0.4 m. This dissertation evaluates a method for obtaining high spatial resolution images of GEO satellites from an Earth based system by measuring the irradiance distribution on the ground resulting from the occultation of the satellite passing in front of a star. The representative size of a GEO satellite combined with the orbital distance results in the ground shadow being consistent with a Fresnel diffraction pattern when observed at visible wavelengths. A measurement of the ground shadow irradiance is used as an amplitude constraint in a Gerchberg-Saxton phase retrieval algorithm that produces a reconstruction of the satellite's 2D transmission function which is analogous to a reverse contrast image of the satellite. The advantage of shadow imaging is that a terrestrial based redundant set of linearly distributed inexpensive small telescopes, each coupled to high speed detectors, is a more effective resolved imaging system for GEO satellites than a very large telescope under ideal conditions. Modeling and simulation efforts indicate sub-meter spatial resolution can be readily achieved using collection apertures of less than 1 meter in diameter. A mathematical basis is established for the treatment of the physical phenomena involved in the shadow imaging process. This includes the source star brightness and angular extent, and the diffraction of starlight from the satellite
Bandres, Miguel A; Gutiérrez-Vega, Julio C
2008-12-08
A very general beam solution of the paraxial wave equation in elliptic cylindrical coordinates is presented. We call such a field an elliptic beam (EB). The complex amplitude of the EB is described by either the generalized Ince functions or the Whittaker-Hill functions and is characterized by four parameters that are complex in the most general situation. The propagation through complex ABCD optical systems and the conditions for square integrability are studied in detail. Special cases of the EB are the standard, elegant, and generalized Ince-Gauss beams, Mathieu-Gauss beams, among others.
International Nuclear Information System (INIS)
Odesskii, A V
2002-01-01
This survey is devoted to associative Z ≥0 -graded algebras presented by n generators and n(n-1)/2 quadratic relations and satisfying the so-called Poincare-Birkhoff-Witt condition (PBW-algebras). Examples are considered of such algebras, depending on two continuous parameters (namely, on an elliptic curve and a point on it), that are flat deformations of the polynomial ring in n variables. Diverse properties of these algebras are described, together with their relations to integrable systems, deformation quantization, moduli spaces, and other directions of modern investigations
Tracking transient events through geosynchronous orbit
DEFF Research Database (Denmark)
Korotova, G.I.; Sibeck, D.G.; Moretto, T.
1999-01-01
Impulsive events in high-latitude dayside ground magnetograms provide evidence for one or more modes of unsteady solar wind-magnetosphere interaction. We use geosynchronous magnetic field and energetic electron observations to demonstrate that the events correspond to abrupt global variations...... in both the magnetospheric magnetic field strength and the energetic electron flux and that these variations are particularly marked in the dayside magnetosphere. The multiple spacecraft observations suggest that the events move both dawnward and duskward from a point of origin on the prenoon magnetopause...... during periods of orthospiral, duskward, and northward interplanetary magnetic field orientation. Event properties are consistent with an interpretation in terms of widespread solar wind pressure fronts striking the bow shock and magnetopause....
Elliptic Hypergeometric Solutions to Elliptic Difference Equations
Directory of Open Access Journals (Sweden)
Alphonse P. Magnus
2009-03-01
Full Text Available It is shown how to define difference equations on particular lattices {x_n}, n in Z, made of values of an elliptic function at a sequence of arguments in arithmetic progression (elliptic lattice. Solutions to special difference equations have remarkable simple interpolatory expansions. Only linear difference equations of first order are considered here.
Elliptic Hypergeometric Solutions to Elliptic Difference Equations
Magnus, Alphonse P.
2009-03-01
It is shown how to define difference equations on particular lattices {xn}, n Î Z, made of values of an elliptic function at a sequence of arguments in arithmetic progression (elliptic lattice). Solutions to special difference equations have remarkable simple interpolatory expansions. Only linear difference equations of first order are considered here.
Özen, Kahraman Esen; Tosun, Murat
2018-01-01
In this study, we define the elliptic biquaternions and construct the algebra of elliptic biquaternions over the elliptic number field. Also we give basic properties of elliptic biquaternions. An elliptic biquaternion is in the form A0 + A1i + A2j + A3k which is a linear combination of {1, i, j, k} where the four components A0, A1, A2 and A3 are elliptic numbers. Here, 1, i, j, k are the quaternion basis of the elliptic biquaternion algebra and satisfy the same multiplication rules which are satisfied in both real quaternion algebra and complex quaternion algebra. In addition, we discuss the terms; conjugate, inner product, semi-norm, modulus and inverse for elliptic biquaternions.
Román-Colón, Miguel O.; Strahler, Alan H.
2007-06-01
We propose an Earth-observation mission Land Observation from Geosynchronous Earth Orbit (LOGEO) to place two spin-scan-stabilized 500-m resolution 9-band VNIR-SWIR imagers in a near-geosynchronous inclined orbit, allowing 15 min observations with a full range of daily sun angles and 30∘ variations in view angle. LOGEO drifts westward at about 4∘ per day, providing geostationary-style coverage for all points on the globe eight times per year. This unique imaging geometry allows accurate retrievals of daily changes in surface bidirectional reflectance, which in turn enhances direct retrieval of biophysical properties, as well as long term and consistent land surface parameters for modeling studies that seek to understand the Earth system and its interactions. For studies of climate and environmental dynamics, LOGEO provides accurate observations of atmospheric aerosols, clouds, as well as other atmospheric constituents across a diverse number of spatial and temporal scales. This collection of land, atmospheric, and climate data products are directly applicable to seven of the nine GEOSS societal benefits areas, providing great opportunities for international collaboration. We also present an overview of LOGEO's systems architecture, as well as top-level design-trade studies and orbital scenarios.
Vehicle with inclinable caterpillars
International Nuclear Information System (INIS)
Carra, O.; Delevallee, A.
1991-01-01
Vehicle has a body with propulsion assemblies that drive caterpillar tracks. When a propulsion unit inclines about its articulation axis it is aided by an advance movement of the caterpillar track in the opposite direction of rotation [fr
Elliptic Quadratic Operator Equations
Ganikhodjaev, Rasul; Mukhamedov, Farrukh; Saburov, Mansoor
2017-01-01
In the present paper is devoted to the study of elliptic quadratic operator equations over the finite dimensional Euclidean space. We provide necessary and sufficient conditions for the existence of solutions of elliptic quadratic operator equations. The iterative Newton-Kantorovich method is also presented for stable solutions.
Troost, Jan
2017-10-01
We clarify three aspects of non-compact elliptic genera. Firstly, we give a path integral derivation of the elliptic genus of the cigar conformal field theory from its non-linear sigma-model description. The result is a manifestly modular sum over a lattice. Secondly, we discuss supersymmetric quantum mechanics with a continuous spectrum. We regulate the theory and analyze the dependence on the temperature of the trace weighted by the fermion number. The dependence is dictated by the regulator. From a detailed analysis of the dependence on the infrared boundary conditions, we argue that in noncompact elliptic genera right-moving supersymmetry combined with modular covariance is anomalous. Thirdly, we further clarify the relation between the flat space elliptic genus and the infinite level limit of the cigar elliptic genus.
Energy Technology Data Exchange (ETDEWEB)
Mineev, Mark [Los Alamos National Laboratory
2008-01-01
The planar elliptic extension of the Laplacian growth is, after a proper parametrization, given in a form of a solution to the equation for areapreserving diffeomorphisms. The infinite set of conservation laws associated with such elliptic growth is interpreted in terms of potential theory, and the relations between two major forms of the elliptic growth are analyzed. The constants of integration for closed form solutions are identified as the singularities of the Schwarz function, which are located both inside and outside the moving contour. Well-posedness of the recovery of the elliptic operator governing the process from the continuum of interfaces parametrized by time is addressed and two examples of exact solutions of elliptic growth are presented.
Forecasting the relativistic electron flux at geosynchronous orbit
Gorney, David J.; Koons, Harry C.
1992-04-01
A neural network, developed to model the temporal variations of relativistic (greater than 3 MeV) electrons at geosynchronous orbit, has been used to make reasonably accurate day-ahead forecasts of the relativistic electron flux at geosynchronous orbit. This model can be used to forecast days when internal discharges might occur on geosynchronous satellites or satellites operating within the outer Van Allen radiation belt. The neural network (in essence, a nonlinear prediction filter) consists of three layers of neurons, containing 10 neurons in the input layer, 6 neurons in a hidden layer, and 1 output neuron. The network inputs consist of ten consecutive days of the daily sum of the planetary magnetic index, Sigma Kp. The output is a prediction of the daily averaged electron flux for the tenth day. The neural network model, together with projections of Sigma Kp based on its historical behavior, can be used to make the day-ahead forecasts of the relativistic electron flux at geosynchronous orbit. A significantly better forecast is obtained by modifying the network to include one additional input, the measured daily averaged electron flux for the day prior to the forecast day, and one more neuron in the hidden layer. Both models are described in this report.
Elliptic Determinantal Processes and Elliptic Dyson Models
Katori, Makoto
2017-10-01
We introduce seven families of stochastic systems of interacting particles in one-dimension corresponding to the seven families of irreducible reduced affine root systems. We prove that they are determinantal in the sense that all spatio-temporal correlation functions are given by determinants controlled by a single function called the spatio-temporal correlation kernel. For the four families {A}_{N-1}, {B}_N, {C}_N and {D}_N, we identify the systems of stochastic differential equations solved by these determinantal processes, which will be regarded as the elliptic extensions of the Dyson model. Here we use the notion of martingales in probability theory and the elliptic determinant evaluations of the Macdonald denominators of irreducible reduced affine root systems given by Rosengren and Schlosser.
Evaporation of inclined water droplets
Kim, Jin Young; Hwang, In Gyu; Weon, Byung Mook
2017-01-01
When a drop is placed on a flat substrate tilted at an inclined angle, it can be deformed by gravity and its initial contact angle divides into front and rear contact angles by inclination. Here we study on evaporation dynamics of a pure water droplet on a flat solid substrate by controlling substrate inclination and measuring mass and volume changes of an evaporating droplet with time. We find that complete evaporation time of an inclined droplet becomes longer as gravitational influence by inclination becomes stronger. The gravity itself does not change the evaporation dynamics directly, whereas the gravity-induced droplet deformation increases the difference between front and rear angles, which quickens the onset of depinning and consequently reduces the contact radius. This result makes the evaporation rate of an inclined droplet to be slow. This finding would be important to improve understanding on evaporation dynamics of inclined droplets. PMID:28205642
Bidispersive-inclined convection
Mulone, Giuseppe; Straughan, Brian
2016-01-01
A model is presented for thermal convection in an inclined layer of porous material when the medium has a bidispersive structure. Thus, there are the usual macropores which are full of a fluid, but there are also a system of micropores full of the same fluid. The model we employ is a modification of the one proposed by Nield & Kuznetsov (2006 Int. J. Heat Mass Transf. 49, 3068–3074. (doi:10.1016/j.ijheatmasstransfer.2006.02.008)), although we consider a single temperature field only. PMID:27616934
Solar Radiation Pressure Binning for the Geosynchronous Orbit
Hejduk, M. D.; Ghrist, R. W.
2011-01-01
Orbital maintenance parameters for individual satellites or groups of satellites have traditionally been set by examining orbital parameters alone, such as through apogee and perigee height binning; this approach ignored the other factors that governed an individual satellite's susceptibility to non-conservative forces. In the atmospheric drag regime, this problem has been addressed by the introduction of the "energy dissipation rate," a quantity that represents the amount of energy being removed from the orbit; such an approach is able to consider both atmospheric density and satellite frontal area characteristics and thus serve as a mechanism for binning satellites of similar behavior. The geo-synchronous orbit (of broader definition than the geostationary orbit -- here taken to be from 1300 to 1800 minutes in orbital period) is not affected by drag; rather, its principal non-conservative force is that of solar radiation pressure -- the momentum imparted to the satellite by solar radiometric energy. While this perturbation is solved for as part of the orbit determination update, no binning or division scheme, analogous to the drag regime, has been developed for the geo-synchronous orbit. The present analysis has begun such an effort by examining the behavior of geosynchronous rocket bodies and non-stabilized payloads as a function of solar radiation pressure susceptibility. A preliminary examination of binning techniques used in the drag regime gives initial guidance regarding the criteria for useful bin divisions. Applying these criteria to the object type, solar radiation pressure, and resultant state vector accuracy for the analyzed dataset, a single division of "large" satellites into two bins for the purposes of setting related sensor tasking and orbit determination (OD) controls is suggested. When an accompanying analysis of high area-to-mass objects is complete, a full set of binning recommendations for the geosynchronous orbit will be available.
An interesting elliptic surface over an elliptic curve
Schütt, Matthias; Shioda, Tetsuji
2007-01-01
We study the elliptic modular surface attached to the commutator subgroup of the modular group. This has an elliptic curve as base and only one singular fibre. We employ an algebraic approach and then consider some arithmetic questions.
International Nuclear Information System (INIS)
Devoto, J.A.
1992-05-01
In a previous paper we studied the modular properties of indices of elliptic operators on twisted loop spaces of manifolds with finite group actions. This motivates the introduction of the universal twisted elliptic genus. This genus can be interpreted as a ring homomorphism from the equivariant bordism ring MU * G to a ring Ell * G . It is shown that the functor X→Ell * G =MU * G (X)x MU * G Ell * G defines an equivariant homology theory, and that the associated cohomology theory satisfies a conjecture of Atiyah and Segal about generalized Lefchetz formulas. (author). 24 refs
Fully nonlinear elliptic equations
Caffarelli, Luis A
1995-01-01
The goal of the book is to extend classical regularity theorems for solutions of linear elliptic partial differential equations to the context of fully nonlinear elliptic equations. This class of equations often arises in control theory, optimization, and other applications. The authors give a detailed presentation of all the necessary techniques. Instead of treating these techniques in their greatest generality, they outline the key ideas and prove the results needed for developing the subsequent theory. Topics discussed in the book include the theory of viscosity solutions for nonlinear equa
Superconducting elliptical cavities
Sekutowicz, J K
2011-01-01
We give a brief overview of the history, state of the art, and future for elliptical superconducting cavities. Principles of the cell shape optimization, criteria for multi-cell structures design, HOM damping schemes and other features are discussed along with examples of superconducting structures for various applications.
Boeing Low-Thrust Geosynchronous Transfer Mission Experience
Poole, Mark; Ho, Monte
2007-01-01
Since 2000, Boeing 702 satellites have used electric propulsion for transfer to geostationary orbits. The use of the 25cm Xenon Ion Propulsion System (25cm XIPS) results in more than a tenfold increase in specific impulse with the corresponding decrease in propellant mass needed to complete the mission when compared to chemical propulsion[1]. In addition to more favorable mass properties, with the use of XIPS, the 702 has been able to achieve orbit insertions with higher accuracy than it would have been possible with the use of chemical thrusters. This paper describes the experience attained by using the 702 XIPS ascent strategy to transfer satellite to geosynchronous orbits.
Energy Technology Data Exchange (ETDEWEB)
Cardona, Carlos [Physics Division, National Center for Theoretical Sciences, National Tsing-Hua University,Hsinchu, Taiwan 30013 (China); Gomez, Humberto [Instituto de Fisica - Universidade de São Paulo,Caixa Postal 66318, 05315-970 São Paulo, SP (Brazil); Facultad de Ciencias Basicas, Universidad Santiago de Cali,Calle 5 62-00 Barrio Pampalinda, Cali, Valle (Colombia)
2016-06-16
Recently the CHY approach has been extended to one loop level using elliptic functions and modular forms over a Jacobian variety. Due to the difficulty in manipulating these kind of functions, we propose an alternative prescription that is totally algebraic. This new proposal is based on an elliptic algebraic curve embedded in a ℂP{sup 2} space. We show that for the simplest integrand, namely the n−gon, our proposal indeed reproduces the expected result. By using the recently formulated Λ−algorithm, we found a novel recurrence relation expansion in terms of tree level off-shell amplitudes. Our results connect nicely with recent results on the one-loop formulation of the scattering equations. In addition, this new proposal can be easily stretched out to hyperelliptic curves in order to compute higher genus.
Kronberg, Max; Soomro, Muhammad Afzal; Top, Jaap
2017-10-01
In this note we extend the theory of twists of elliptic curves as presented in various standard texts for characteristic not equal to two or three to the remaining characteristics. For this, we make explicit use of the correspondence between the twists and the Galois cohomology set H^1\\big({G}_{\\overline{K}/K}, \\operatorname{Aut}_{\\overline{K}}(E)\\big). The results are illustrated by examples.
Sadler, Elaine M.; Oosterloo, Tom; Morganti, Raffaella
2002-01-01
Neutral hydrogen is an important component of the interstellar medium in elliptical galaxies as well as a potentially valuable mass tracer. Until recently, HI surveys of early-type galaxies have been sparse and inhomogeneous but this has changed with the advent of the HI Parkes All-Sky Survey (HIPASS; Barnes et al. 2001). We discuss HIPASS observations of a sample of ~2500 nearby E/S0 galaxies, as well as detailed HI imaging of a range of individual objects.
Anisotropic elliptic optical fibers
Kang, Soon Ahm
1991-05-01
The exact characteristic equation for an anisotropic elliptic optical fiber is obtained for odd and even hybrid modes in terms of infinite determinants utilizing Mathieu and modified Mathieu functions. A simplified characteristic equation is obtained by applying the weakly guiding approximation such that the difference in the refractive indices of the core and the cladding is small. The simplified characteristic equation is used to compute the normalized guide wavelength for an elliptical fiber. When the anisotropic parameter is equal to unity, the results are compared with the previous research and they are in close agreement. For a fixed value normalized cross-section area or major axis, the normalized guide wavelength lambda/lambda(sub 0) for an anisotropic elliptic fiber is small for the larger value of anisotropy. This condition indicates that more energy is carried inside of the fiber. However, the geometry and anisotropy of the fiber have a smaller effect when the normalized cross-section area is very small or very large.
The properties of radio ellipticals
International Nuclear Information System (INIS)
Sparks, W.B.; Disney, M.J.; Rodgers, A.W.
1984-01-01
Optical and additional radio data are presented for the bright galaxies of the Disney and Wall survey (1977 Mon. Not. R. Astron. Soc. 179, 235). These data form the basis of a statistical comparison of the properties of radio elliptical galaxies to radio-quiet ellipticals. The correlations may be explained by the depth of the gravitational potential well in which the galaxy resides governing the circumstances under which an elliptical galaxy rids itself of internally produced gas. (author)
Intelligent Observation Strategies for Geosynchronous Remote Sensing for Natural Hazards
Moe, K.; Cappelaere, P. G.; Frye, S. W.; LeMoigne, J.; Mandl, D.; Flatley, T.; Geist, A.
2015-12-01
Geosynchronous satellites offer a unique perspective for monitoring environmental factors important to understanding natural hazards and supporting the disasters management life cycle, namely forecast, detection, response, recovery and mitigation. In the NASA decadal survey for Earth science, the GEO-CAPE mission was proposed to address coastal and air pollution events in geosynchronous orbit, complementing similar initiatives in Asia by the South Koreans and by ESA in Europe, thereby covering the northern hemisphere. In addition to analyzing the challenges of identifying instrument capabilities to meet the science requirements, and the implications of hosting the instrument payloads on commercial geosynchronous satellites, the GEO-CAPE mission design team conducted a short study to explore strategies to optimize the science return for the coastal imaging instrument. The study focused on intelligent scheduling strategies that took into account cloud avoidance techniques as well as onboard processing methods to reduce the data storage and transmission loads. This paper expands the findings of that study to address the use of intelligent scheduling techniques and near-real time data product acquisition of both the coastal water and air pollution events. The topics include the use of onboard processing to refine and execute schedules, to detect cloud contamination in observations, and to reduce data handling operations. Analysis of state of the art flight computing capabilities will be presented, along with an assessment of cloud detection algorithms and their performance characteristics. Tools developed to illustrate operational concepts will be described, including their applicability to environmental monitoring domains with an eye to the future. In the geostationary configuration, the payload becomes a networked "thing" with enough connectivity to exchange data seamlessly with users. This allows the full field of view to be sensed at very high rate under the
Intelligent Observation Strategies for Geosynchronous Remote Sensing for Natural Hazards
Moe, Karen; Cappleare, Patrice; Frye, Stuart; LeMoigne, Jacqueline; Mandl, Daniel; Flatley, Thomas; Geist, Alessandro
2015-01-01
Geosynchronous satellites offer a unique perspective for monitoring environmental factors important to understanding natural hazards and supporting the disasters management life cycle, namely forecast, detection, response, recovery and mitigation. In the NASA decadal survey for Earth science, the GEO-CAPE mission was proposed to address coastal and air pollution events in geosynchronous orbit, complementing similar initiatives in Asia by the South Koreans and by ESA in Europe, thereby covering the northern hemisphere. In addition to analyzing the challenges of identifying instrument capabilities to meet the science requirements, and the implications of hosting the instrument payloads on commercial geosynchronous satellites, the GEO-CAPE mission design team conducted a short study to explore strategies to optimize the science return for the coastal imaging instrument. The study focused on intelligent scheduling strategies that took into account cloud avoidance techniques as well as onboard processing methods to reduce the data storage and transmission loads. This paper expands the findings of that study to address the use of intelligent scheduling techniques and near-real time data product acquisition of both the coastal water and air pollution events. The topics include the use of onboard processing to refine and execute schedules, to detect cloud contamination in observations, and to reduce data handling operations. Analysis of state of the art flight computing capabilities will be presented, along with an assessment of cloud detection algorithms and their performance characteristics. Tools developed to illustrate operational concepts will be described, including their applicability to environmental monitoring domains with an eye to the future. In the geostationary configuration, the payload becomes a networked thing with enough connectivity to exchange data seamlessly with users. This allows the full field of view to be sensed at very high rate under the control
Elliptic partial differential equations
Han, Qing
2011-01-01
Elliptic Partial Differential Equations by Qing Han and FangHua Lin is one of the best textbooks I know. It is the perfect introduction to PDE. In 150 pages or so it covers an amazing amount of wonderful and extraordinary useful material. I have used it as a textbook at both graduate and undergraduate levels which is possible since it only requires very little background material yet it covers an enormous amount of material. In my opinion it is a must read for all interested in analysis and geometry, and for all of my own PhD students it is indeed just that. I cannot say enough good things abo
Wide-field high-performance geosynchronous imaging
International Nuclear Information System (INIS)
Wood, H. John; Jenstrom, Del; Wilson, Mark; Hinkal, Sanford; Kirchman, Frank
1998-01-01
The NASA Mission to Planet Earth (MTPE) Program and the National Oceanographic and Atmospheric Administration (NOAA) are sponsoring the Advanced Geosynchronous Studies (AGS) to develop technologies and system concepts for Earth observation from geosynchronous orbit. This series of studies is intended to benefit both MTPE science and the NOAA GOES Program. Within the AGS program, advanced imager trade studies have investigated two candidate concepts for near-term advanced geosynchronous imagers. One concept uses a scan mirror to direct the line of sight from a 3-axis stabilized platform. Another eliminates the need for a scan mirror by using an agile spacecraft bus to scan the entire instrument. The purpose of this paper is to discuss the optical design trades and system issues encountered in evaluating the two scanning approaches. The imager design started with a look at first principles: what is the most efficient way to image the Earth in those numerous spectral bands of interest to MTPE scientists and NOAA weather forecasters. Optical design trades included rotating filter wheels and dispersive grating instruments. The design converged on a bandpass filter instrument using four focal planes to cover the spectral range 0.45 to 13.0 micrometers. The first imager design uses a small agile spacecraft supporting an afocal optical telescope. Dichroic beamsplitters feed refractive objectives to four focal planes. The detectors are a series of long linear and rectangular arrays which are scanned in a raster fashion over the 17 degree Earth image. The use of the spacecraft attitude control system to raster the imager field-of-view (FOV) back and forth over the Earth eliminates the need for a scan mirror. However, the price paid is significant energy and time required to reverse the spacecraft slew motions at the end of each scan line. Hence, it is desired to minimize the number of scan lines needed to cover the full Earth disk. This desire, coupled with the ground
Analysis on Space Environment from the Anomalies of Geosynchronous Satellites
Directory of Open Access Journals (Sweden)
Jaejin Lee
2009-12-01
Full Text Available While it is well known that space environment can produce spacecraft anomaly, defining space environment effects for each anomalies is difficult. This is caused by the fact that spacecraft anomaly shows various symptoms and reproducing it is impossible. In this study, we try to find the conditions of when spacecraft failures happen more frequently and give satellite operators useful information. Especially, our study focuses on the geosynchronous satellites which cost is high and required high reliability. We used satellite anomaly data given by Satellite News Digest which is internet newspaper providing space industry news. In our analysis, 88 anomaly cases occurred from 1997 to 2008 shows bad corelation with Kp index. Satellite malfunctions were likely to happen in spring and fall and in local time from midnight to dawn. In addition, we found the probability of anomaly increase when high energy electron flux is high. This is more clearly appeared in solar minimum than maximum period.
Analysis of three-dimensional interference patterns of an inclined capillary.
Zhang, Yiding; Xu, Mingfeng; Tian, Wenjing; Xu, Qiwei; Xiao, Jinghua
2016-08-01
We study the interference patterns from an inclined capillary tube filled with liquid by using the ray tracing method and interference theory. A beautiful elliptical pattern is found on the screen, with refined fringes embedded in it. Particularly, the fringes on top of the pattern are continuously swallowed to the center with the angle of incidence increasing. In addition, a method is demonstrated to determine the refractive index of the liquid and the wavelength of the incident light by measuring the capillary tilt of every 10-fringe being swallowed, which looks like fringe crossover, with respect to the change of the inclined angle of the capillary.
Fast computation of complete elliptic integrals and Jacobian elliptic functions
Fukushima, Toshio
2009-12-01
As a preparation step to compute Jacobian elliptic functions efficiently, we created a fast method to calculate the complete elliptic integral of the first and second kinds, K( m) and E( m), for the standard domain of the elliptic parameter, 0 procedure to compute simultaneously three Jacobian elliptic functions, sn( u| m), cn( u| m), and dn( u| m), by repeated usage of the double argument formulae starting from the Maclaurin series expansions with respect to the elliptic argument, u, after its domain is reduced to the standard range, 0 ≤ u procedure is 25-70% faster than the methods based on the Gauss transformation such as Bulirsch’s algorithm, sncndn, quoted in the Numerical Recipes even if the acceleration of computation of K( m) is not taken into account.
The strv 1 microsatellite semes: Exploiting the geosynchronous transfer orbit
Blott, R. J.; Wells, N. S.; Eves, J.
Following 3 successful years in orbit, the UK Defence Evaluation and Research Agency's two Space Technology Research Vehicle microsatellites (STRV) 1 a&b will be followed by a second mission. STRV 1 c&d are now in construction for a planned launch in 1999. The new mission, which includes 22 experimental payloads and developmental spacecraft bus technologies from European, US and Canadian military, civil and commercial sponsors, exploits the Geosynchronous Transfer Orbit (GTO) to offer an affordable, working space research tool for both government and industry. The STRV 1 programme objective is to promote the enhancement of military and civil space communications, remote sensing and navigation capabilities at reduced cost and risk. Additional aims are to help industry to achieve commercial benefit from investment in emerging technologies and to develop the synergy between government, commercial and civilian space applications. The paper explains how STRV 1 exploits the variable altitude and high radiation environment of GTO to investigate the performance of emerging technologies and techniques. This includes the accelerated life testing of components and materials, such as infra-red detectors, advanced microprocessors and solar cell technologies, and the prototyping of new techniques to improve communications and spacecraft autonomy. Experiments include implementing a secure version of the Consultative Committee for Space Data Systems (CCSDS) packet telecommand and telemetry standards, further development of the Internet-based Space Communication Protocol Standards (SCPS) and evaluating the exploitation of the Global Positioning System (GPS) in geosynchronous orbit. The new mission also builds on and extends the comprehensive environmental monitoring achieved by STRV 1 a&b.
Devour, Brian M.; Bell, Eric F.
2017-06-01
Accurate measurement of galaxy structures is a prerequisite for quantitative investigation of galaxy properties or evolution. Yet, the impact of galaxy inclination and dust on commonly used metrics of galaxy structure is poorly quantified. We use infrared data sets to select inclination-independent samples of disc and flattened elliptical galaxies. These samples show strong variation in Sérsic index, concentration and half-light radii with inclination. We develop novel inclination-independent galaxy structures by collapsing the light distribution in the near-infrared on to the major axis, yielding inclination-independent 'linear' measures of size and concentration. With these new metrics we select a sample of Milky Way analogue galaxies with similar stellar masses, star formation rates, sizes and concentrations. Optical luminosities, light distributions and spectral properties are all found to vary strongly with inclination: When inclining to edge-on, r-band luminosities dim by >1 magnitude, sizes decrease by a factor of 2, 'dust-corrected' estimates of star formation rate drop threefold, metallicities decrease by 0.1 dex and edge-on galaxies are half as likely to be classified as star forming. These systematic effects should be accounted for in analyses of galaxy properties.
Elliptical Orbit Performance Computer Program
Myler, T.
1984-01-01
Elliptical Orbit Performance (ELOPE) computer program for analyzing orbital performance of space boosters uses orbit insertion data obtained from trajectory simulation to generate parametric data on apogee and perigee altitudes as function of payload data. Data used to generate presentation plots that display elliptical orbit performance capability of space booster.
A system for predicting close approaches and potential collisions in geosynchronous orbits
Beusch, J.; Abbot, R.; Sridharan, R.
The geosynchronous orbit is getting crowded with over 300 active, revenue producing large satellites and over 500 inactive dead resident space objects that pose a physical collision threat to the active satellites. The in situ demise of a particular satellite, Telstar 401, followed by a similar demise of SOLIDARIDAD 1, initiated a research and development effort at MIT Lincoln Laboratory to address this threat. This work with commercial satellite operators is accomplished using the mechanism of Cooperative Research and Development Agreements. Initial work to detect and warn of close approaches with these two failed satellites led to more extensive research on the collision threat over the entire geosynchronous belt. It is apparent that: a) There is a significant probability of collision; b) The probability has increased considerably in the last decade or so; c) The continuing failure of geosynchronous satellites and injection of rocket bodies into or near geosynchronous orbit will increase the threat; d) Debris in or near geosynchronous orbit poses another problem that has to be addressed. This paper surveys what has been achieved so far in predicting the threat and protecting satellites. An assessment of the probability of collision is presented as well as a description of the Geosynchronous Monitoring and Warning System. The operations of the GMWS are described as well as some of the results achieved so far. Areas of current research are mentioned.
Elliptic Curves and Number Theory
Indian Academy of Sciences (India)
R. Sujatha, School of Mathematics, Tata Institute of Fundamental Research, Mumbai, INDIA
1. Aim: To explain the connection between a simple ancient problem in number theory and a deep sophisticated conjecture about Elliptic Curves. ('arithmetic Geometry'). Notation: N : set of natural numbers (1,2,3,...) ...
Ferguson, Henry C.; Binggeli, Bruno
1994-01-01
Dwarf elliptical (dE) galaxies, with blue absolute magnitudes typically fainter than M(sub B) = -16, are the most numerous type of galaxy in the nearby universe. Tremendous advances have been made over the past several years in delineating the properties of both Local Group satellite dE's and the large dE populations of nearby clusters. We review some of these advances, with particular attention to how well currently availiable data can constrain (a) models for the formation of dE's, (b) the physical and evolutionary connections between different types of galaxies that overlap in the same portion of the mass-spectrum of galaxies, (c) the contribution of dE's to the galaxy luminosity functions in clusters and the field, (d) the star-forming histories of dE's and their possible contribution to faint galaxy counts, and (e) the clustering properties of dE's. In addressing these issues, we highlight the extent to which selection effects temper these constraints, and outline areas where new data would be particularly valuable.
Ring/Shell Ion Distributions at Geosynchronous Orbit
Thomsen, M. F.; Denton, M. H.; Gary, S. P.; Liu, Kaijun; Min, Kyungguk
2017-12-01
One year's worth of plasma observations from geosynchronous orbit is examined for ion distributions that may simultaneously be subject to the ion Bernstein (IB) instability (generating fast magnetosonic waves) and the Alfvén cyclotron (AC) instability (generating electromagnetic ion cyclotron waves). Confirming past analyses, distributions with robust ∂fp(v⊥)/∂v⊥ > 0 near v|| = 0, which we denote as "ring/shell" distributions, are commonly found primarily on the dayside of the magnetosphere. A new approach to high-fidelity representation of the observed ring/shell distribution functions in a form readily suited to both analytical moment calculation and linear dispersion analysis is presented, which allows statistical analysis of the ring/shell properties. The ring/shell temperature anisotropy is found to have a clear upper limit that depends on the parallel beta of the ring/shell (β||r) in a manner that is diagnostic of the operation of the AC instability. This upper limit is only reached in the postnoon events, which are primarily produced by the energy- and pitch angle-dependent magnetic drifts of substorm-injected ions. Further, it is primarily the leading edge of such injections, where the distribution is strongly ring-like, that the AC instability appears to be operating. By contrast, the ratio of the ring energy to the Alfvén energy remains well within the range of 0.25-4.0 suitable for IB instability throughout essentially all of the events, except those that occur in denser cold plasma of the outer plasmasphere.
Two satellite study of substorm expansion near geosynchronous orbit
Directory of Open Access Journals (Sweden)
Ø. Holter
2004-12-01
Full Text Available During several time intervals in 1979–1980 the satellites GEOS-2 and SCATHA were situated relatively close on the nightside of the Earth at geosynchronous distances. Several substorm events were identified during these periods. The event considered in this paper was recorded on 22 May 1979, when the satellites were separated by less than 30min in local time around 21:00 LT. The observed 45 to 60 s delay of magnetic signatures observed at the two s/c indicates a westward expansion of ~7.7°/min. At the two s/c, the magnetic signatures are, in particular for the azimuthal magnetic field components, quite different. At GEOS-2, being close to the magnetic equator, the dominant feature is a dipolarization with a weak field-aligned current signature corresponding to a symmetric current which cancels at the equator. On SCATHA, however, being close to the current sheet boundary, the azimuthal magnetic field indicates a strong field-aligned Birkeland current structure. On both s/c the first indication of an approaching substorm was an increase in the high energy ion flux followed by a reduction in the flux intensity of energetic electrons and a further tailward stretching of the magnetic field, starting ~2min before the onset of the magnetic field dipolarization. The tailward stretching, the observed variations of the magnetic field components, and the subsequent dipolarization are interpreted in terms of an azimuthally tilted field-aligned current system passing the s/c on the tailward side from east to west. The westward expansion and dipolarization observed at the two s/c are consistent with the propagation of a Rayleigh-Taylor type instability. The increased radial ion flux corresponds to the ExB-drift due to the substorm associated electric field.
Key words. Magnetospheric physics (storms and substorms; plasma waves and instabilities; current systems
Rational points on elliptic curves
Silverman, Joseph H
2015-01-01
The theory of elliptic curves involves a pleasing blend of algebra, geometry, analysis, and number theory. This book stresses this interplay as it develops the basic theory, thereby providing an opportunity for advanced undergraduates to appreciate the unity of modern mathematics. At the same time, every effort has been made to use only methods and results commonly included in the undergraduate curriculum. This accessibility, the informal writing style, and a wealth of exercises make Rational Points on Elliptic Curves an ideal introduction for students at all levels who are interested in learning about Diophantine equations and arithmetic geometry. Most concretely, an elliptic curve is the set of zeroes of a cubic polynomial in two variables. If the polynomial has rational coefficients, then one can ask for a description of those zeroes whose coordinates are either integers or rational numbers. It is this number theoretic question that is the main subject of this book. Topics covered include the geometry and ...
GEOMETRIC PROGRESSIONS ON ELLIPTIC CURVES.
Ciss, Abdoul Aziz; Moody, Dustin
2017-01-01
In this paper, we look at long geometric progressions on different model of elliptic curves, namely Weierstrass curves, Edwards and twisted Edwards curves, Huff curves and general quartics curves. By a geometric progression on an elliptic curve, we mean the existence of rational points on the curve whose x -coordinate (or y -coordinate) are in geometric progression. We find infinite families of twisted Edwards curves and Huff curves with geometric progressions of length 5, an infinite family of Weierstrass curves with 8 term progressions, as well as infinite families of quartic curves containing 10-term geometric progressions.
Energy and the Elliptical Orbit
Nettles, Bill
2009-03-01
In the January 2007 issue of The Physics Teacher, Prentis, Fulton, Hesse, and Mazzino describe a laboratory exercise in which students use a geometrical analysis inspired by Newton to show that an elliptical orbit and an inverse-square law force go hand in hand. The historical, geometrical, and teamwork aspects of the exercise are useful and important. This paper presents an exercise which uses an energy/angular momentum conservation model for elliptical orbits. This exercise can be done easily by an individual student and on regular notebook-sized paper.
Tian, Gang
2002-11-26
We discuss some recent progress on the regularity theory of the elliptic Yang-Mills equation. We start with some basic properties of the elliptic Yang-Mills equation, such as Coulomb gauges, monotonicity, and curvature estimates. Next we discuss singularity of stationary Yang-Mills connections and compactness theorems on Yang-Mills connections with bounded L(2) norm of curvature. We also discuss in some detail self-dual solutions of the Yang-Mills equation and describe a compactification of their moduli space.
Tian, Gang
2002-01-01
We discuss some recent progress on the regularity theory of the elliptic Yang–Mills equation. We start with some basic properties of the elliptic Yang–Mills equation, such as Coulomb gauges, monotonicity, and curvature estimates. Next we discuss singularity of stationary Yang–Mills connections and compactness theorems on Yang–Mills connections with bounded L2 norm of curvature. We also discuss in some detail self-dual solutions of the Yang–Mills equation and describe a compactification of the...
Elliptic net and its cryptographic application
Muslim, Norliana; Said, Mohamad Rushdan Md
2017-11-01
Elliptic net is a generalization of elliptic divisibility sequence and in cryptography field, most cryptographic pairings that are based on elliptic curve such as Tate pairing can be improved by applying elliptic nets algorithm. The elliptic net is constructed by using n dimensional array of values in rational number satisfying nonlinear recurrence relations that arise from elliptic divisibility sequences. The two main properties hold in the recurrence relations are for all positive integers m>n, hm +nhm -n=hm +1hm -1hn2-hn +1hn -1hm2 and hn divides hm whenever n divides m. In this research, we discuss elliptic divisibility sequence associated with elliptic nets based on cryptographic perspective and its possible research direction.
Newton flows for elliptic functions
Helminck, G.F.; Twilt, F.
2015-01-01
Newton flows are dynamical systems generated by a continuous, desingularized Newton method for mappings from a Euclidean space to itself. We focus on the special case of meromorphic functions on the complex plane. Inspired by the analogy between the rational (complex) and the elliptic (i.e., doubly
Second order degenerate elliptic equations
International Nuclear Information System (INIS)
Duong Minh Duc.
1988-08-01
Using an improved Sobolev inequality we study a class of elliptic operators which is degenerate inside the domain and strongly degenerate near the boundary of the domain. Our results are applicable to the L 2 -boundary value problem and the mixed boundary problem. (author). 18 refs
Energy and the Elliptical Orbit
Nettles, Bill
2009-01-01
In the January 2007 issue of "The Physics Teacher," Prentis, Fulton, Hesse, and Mazzino describe a laboratory exercise in which students use a geometrical analysis inspired by Newton to show that an elliptical orbit and an inverse-square law force go hand in hand. The historical, geometrical, and teamwork aspects of the exercise are useful and…
Diffeomorphisms of elliptic 3-manifolds
Hong, Sungbok; McCullough, Darryl; Rubinstein, J Hyam
2012-01-01
This work concerns the diffeomorphism groups of 3-manifolds, in particular of elliptic 3-manifolds. These are the closed 3-manifolds that admit a Riemannian metric of constant positive curvature, now known to be exactly the closed 3-manifolds that have a finite fundamental group. The (Generalized) Smale Conjecture asserts that for any elliptic 3-manifold M, the inclusion from the isometry group of M to its diffeomorphism group is a homotopy equivalence. The original Smale Conjecture, for the 3-sphere, was proven by J. Cerf and A. Hatcher, and N. Ivanov proved the generalized conjecture for many of the elliptic 3-manifolds that contain a geometrically incompressible Klein bottle. The main results establish the Smale Conjecture for all elliptic 3-manifolds containing geometrically incompressible Klein bottles, and for all lens spaces L(m,q) with m at least 3. Additional results imply that for a Haken Seifert-fibered 3 manifold V, the space of Seifert fiberings has contractible components, and apart from a small...
Khechai, Abdelhak; Tati, Abdelouahab; Belarbi, Mohamed Ouejdi; Guettala, Abdelhamid
2018-03-01
The design of high-performance composite structures frequently includes discontinuities to reduce the weight and fastener holes for joining. Understanding the behavior of perforated laminates is necessary for structural design. In the current work, stress concentrations taking place in laminated and isotropic plates subjected to tensile load are investigated. The stress concentrations are obtained using a recent quadrilateral finite element of four nodes with 32 DOFs. The present finite element (PE) is a combination of two finite elements. The first finite element is a linear isoparametric membrane element and the second is a high precision Hermitian element. One of the essential objectives of the current investigation is to confirm the capability and efficiency of the PE for stress determination in perforated laminates. Different geometric parameters, such as the cutout form, sizes and cutout orientations, which have a considerable effect on the stress values, are studied. Using the present finite element formulation, the obtained results are found to be in good agreement with the analytical findings, which validates the capability and the efficiency of the proposed formulation. Finally, to understand the material parameters effect such as the orientation of fibers and degree of orthotropy ratio on the stress values, many figures are presented using different ellipse major to minor axis ratio. The stress concentration values are considerably affected by increasing the orientation angle of the fibers and degree of orthotropy.
Legendre Elliptic Curves over Finite Fields
Auer, Roland; Top, Jakob
2002-01-01
We show that every elliptic curve over a finite field of odd characteristic whose number of rational points is divisible by 4 is isogenous to an elliptic curve in Legendre form, with the sole exception of a minimal respectively maximal elliptic curve. We also collect some results concerning the
Elliptic Diophantine equations a concrete approach via the elliptic logarithm
Tzanakis, Nikos
2013-01-01
This book presents in a unified way the beautiful and deep mathematics, both theoretical and computational, on which the explicit solution of an elliptic Diophantine equation is based. It collects numerous results and methods that are scattered in literature. Some results are even hidden behind a number of routines in software packages, like Magma. This book is suitable for students in mathematics, as well as professional mathematicians.
Coordinated ground-based and geosynchronous satellite-based measurements of auroral pulsations
Energy Technology Data Exchange (ETDEWEB)
Suszcynsky, David M.; Borovsky, Joseph E.; Thomsen, Michelle F.; McComas, David J.; Belian, Richard D.
1996-09-01
We describe a technique that uses a ground-based all-sky video camera and geosynchronous satellite-based plasma and energetic particle detectors to study ionosphere-magnetosphere coupling as it relates to the aurora. The video camera system was deployed in Eagle, Alaska for a seven month period at the foot of the magnetic field line that threads geosynchronous satellite 1989-046. Since 1989-046 corotates with the earth, its footprint remains nearly fixed in the vicinity of Eagle, allowing for routine continuous monitoring of an auroral field line at its intersections with the ground and with geosynchronous orbit. As an example of the utility of this technique, we present coordinated ground-based and satellite based observations during periods of auroral pulsations and compare this data to the predictions of both the relaxation oscillator theory and flow cyclotron maser theory for the generation of pulsating aurorae. The observed plasma and energetic particle characteristics at geosynchronous orbit during pulsating aurorae displays are found to be in agreement with the predictions of both theories lending further support that a cyclotron resonance mechanism is responsible for auroral pulsations.
Measuring the magnetic connectivity of the geosynchronous region of the magnetosphere
International Nuclear Information System (INIS)
Thomsen, M.; Hones, E.; McComas, D.; Reeves, G.; Weiss, L.
1996-01-01
This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The purpose of this project was to determine the magnetic connectivity of the geosynchronous region of the magnetosphere to the auroral zone in the polar ionosphere in order to test and refine current magnetospheric magnetic field models. The authors used plasma data from LANL instruments on three geosynchronous satellites and from USAF instruments on three low-altitude, polar-orbiting, DMSP satellites. Magnetic connectivity is tested by comparing plasma energy spectra at DMSP and geosynchronous satellites when they are in near conjunction. The times of closest conjugacy are used to evaluate the field models. They developed the tools for each step of the process and applied them to the study of a one-week test set of conjunctions. They automated the analysis tools and applied them to four months of two-satellite observations. This produced a database of about 130 definitive magnetic conjunctions. They compared this database with the predictions of the widely-used Tsyganenko magnetic field model and showed that in most cases one of the various parameterizations of the model could reproduce the observed field line connection. Further, they explored various measurables (e.g., magnetospheric activity indices or the geosynchronous field orientation) that might point to the appropriate parameterization of the model for these conjunctions, and ultimately, for arbitrary times
Directory of Open Access Journals (Sweden)
Y. Shi
2009-02-01
Full Text Available Determination of the radial profile of phase space density of relativistic electrons at constant adiabatic invariants is crucial for identifying the source for them within the outer radiation belt. The commonly used method is to convert flux observed at fixed energy to phase space density at constant first, second and third adiabatic invariants, which requires an empirical global magnetic field model and thus might produce some uncertainties in the final results. From a different perspective, in this paper we indirectly infer the shape of the radial profile of phase space density of relativistic electrons near the geosynchronous region by statistically examining the geosynchronous energetic flux response to 128 solar wind dynamic pressure enhancements during the years 2000 to 2003. We thus avoid the disadvantage of using empirical magnetic field models. Our results show that the flux response is species and energy dependent. For protons and low-energy electrons, the primary response to magnetospheric compression is an increase in flux at geosynchronous orbit. For relativistic electrons, the dominant response is a decrease in flux, which implies that the phase space density decreases toward increasing radial distance at geosynchronous orbit and leads to a local peak inside of geosynchronous orbit. The flux response of protons and non-relativistic electrons could result from a phase density that increases toward increasing radial distance, but this cannot be determined for sure due to the particle energization associated with pressure enhancements. Our results for relativistic electrons are consistent with previous results obtained using magnetic field models, thus providing additional confirmation that these results are correct and indicating that they are not the result of errors in their selected magnetic field model.
Elliptical and lenticular galaxies evolution
International Nuclear Information System (INIS)
Vigroux, L.
1981-01-01
Different evolutionnary models for elliptical and lenticular galaxies are discussed. In the first part, we show that, at least some peculiar early types galaxies exhibit some activity. Then we describe the observationnal constraints: the color-magnitude diagram, the color gradient and the high metallicity of intraclusters gas. Among the different models, only the dissipation collapse followed by a hot wind driven by supernovae explosion explain in a natural way these constraints. Finally, the origin of SO is briefly discussed [fr
Coherent states with elliptical polarization
Colavita, E.; Hacyan, S.
2004-01-01
Coherent states of the two dimensional harmonic oscillator are constructed as superpositions of energy and angular momentum eigenstates. It is shown that these states are Gaussian wave-packets moving along a classical trajectory, with a well defined elliptical polarization. They are coherent correlated states with respect to the usual cartesian position and momentum operators. A set of creation and annihilation operators is defined in polar coordinates, and it is shown that these same states ...
Holomorphic bundles over elliptic manifolds
International Nuclear Information System (INIS)
Morgan, J.W.
2000-01-01
In this lecture we shall examine holomorphic bundles over compact elliptically fibered manifolds. We shall examine constructions of such bundles as well as (duality) relations between such bundles and other geometric objects, namely K3-surfaces and del Pezzo surfaces. We shall be dealing throughout with holomorphic principal bundles with structure group GC where G is a compact, simple (usually simply connected) Lie group and GC is the associated complex simple algebraic group. Of course, in the special case G = SU(n) and hence GC = SLn(C), we are considering holomorphic vector bundles with trivial determinant. In the other cases of classical groups, G SO(n) or G = Sympl(2n) we are considering holomorphic vector bundles with trivial determinant equipped with a non-degenerate symmetric, or skew symmetric pairing. In addition to these classical cases there are the finite number of exceptional groups. Amazingly enough, motivated by questions in physics, much interest centres around the group E8 and its subgroups. For these applications it does not suffice to consider only the classical groups. Thus, while often first doing the case of SU(n) or more generally of the classical groups, we shall extend our discussions to the general semi-simple group. Also, we shall spend a good deal of time considering elliptically fibered manifolds of the simplest type, namely, elliptic curves
Flattening and radio emission among elliptical galaxies
International Nuclear Information System (INIS)
Disney, M.J.; Sparks, W.B.; Wall, J.V.
1984-01-01
In a sample of 132 bright elliptical galaxies it is shown that there is a strong correlation between radio activity and flattening in the sense that radio ellipticals are both apparently and inherently rounder than the average elliptical. Both extended and compact sources are subject to the same correlation. No galaxies with axial ratios below 0.65 are found to be radio emitters. (author)
On Fibonacci Numbers Which Are Elliptic Carmichael
2014-12-27
On Fibonacci numbers which are elliptic Carmichael Florian Luca School of Mathematics University of the Witwatersrand P. O. Box Wits 2050, South...CM elliptic curve with CM field different from Q( √ −1), then the set of n for which the nth Fibonacci number Fn is elliptic Carmichael for E is of...Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law
Elliptic hypergeometric functions associated with root systems
Rosengren, Hjalmar; Warnaar, S. Ole
2017-01-01
We give a survey of elliptic hypergeometric functions associated with root systems, comprised of three main parts. The first two form in essence an annotated table of the main evaluation and transformation formulas for elliptic hypergeometric integeral and series on root systems. The third and final part gives an introduction to Rains' elliptic Macdonald-Koornwinder theory (in part also developed by Coskun and Gustafson).
Doppler Velocity Signatures of Idealized Elliptical Vortices
Directory of Open Access Journals (Sweden)
Wen-Chau Lee
2006-01-01
Full Text Available Doppler radar observations have revealed a class of atmospheric vortices (tropical cyclones, tornadoes, dust devils that possess elliptical radar reflectivity signatures. One famous example is Typhoon Herb (1996 that maintained its elliptical reflectivity structure over a 40-hour period. Theoretical work and dual-Doppler analyses of observed tropical cyclones have suggested two physical mechanisms that can explain the formation of two types of elliptical vortices observed in nature, namely, the combination of a circular vortex with either a wavenumber two vortex Rossby wave or a deformation field. The characteristics of these two types of elliptical vortices and their corresponding Doppler velocity signatures have not been previously examined.
Arbitrarily elliptical-cylindrical invisible cloaking
International Nuclear Information System (INIS)
Jiang Weixiang; Cui Tiejun; Yu Guanxia; Lin Xianqi; Cheng Qiang; Chin, J Y
2008-01-01
Based on the idea of coordinate transformation (Pendry, Schurig and Smith 2006 Science 312 1780), arbitrarily elliptical-cylindrical cloaks are proposed and designed. The elliptical cloak, which is composed of inhomogeneous anisotropic metamaterials in an elliptical-shell region, will deflect incoming electromagnetic (EM) waves and guide them to propagate around the inner elliptical region. Such EM waves will return to their original propagation directions without distorting the waves outside the elliptical cloak. General formulations of the inhomogeneous and anisotropic permittivity and permeability tensors are derived for arbitrarily elliptical axis ratio k, which can also be used for the circular cloak when k = 1. Hence the elliptical cloaks can make a large range of objects invisible, from round objects (when k approaches 1) to long and thin objects (when k is either very large or very small). We also show that the material parameters in elliptical cloaking are singular at only two points, instead of on the whole inner circle for circular cloaking, which are much easier to be realized in actual applications. Full-wave simulations are given to validate the arbitrarily elliptical cloaking
Dark matter in elliptical galaxies
Carollo, C. M.; Zeeuw, P. T. DE; Marel, R. P. Van Der; Danziger, I. J.; Qian, E. E.
1995-01-01
We present measurements of the shape of the stellar line-of-sight velocity distribution out to two effective radii along the major axes of the four elliptical galaxies NGC 2434, 2663, 3706, and 5018. The velocity dispersion profiles are flat or decline gently with radius. We compare the data to the predictions of f = f(E, L(sub z)) axisymmetric models with and without dark matter. Strong tangential anisotropy is ruled out at large radii. We conclude from our measurements that massive dark halos must be present in three of the four galaxies, while for the fourth galaxy (NGC 2663) the case is inconclusive.
Meter-level orbit determination of geosynchronous satellites by an economical tracking system
Culp, R. D.; Wang, T.-H.
Covariance analyses to study the performance of a proposed high precision and low cost geosynchronous satellites tracking system are presented. The tracking systems main components are one TDRS, a near-by geosynchronous satellite, 4-5 automatic ground stations, and a Very Long Baseline Interferometric (VLBI) system. The automated ground station provides doubly differenced ranging measurements without precision clock. The VLBI system consists of 4 one meter antennas positioned on orthogonal 6000 km baselines and uses a GPS signal for clock synchronization. Based on the anticipated characteristics of the 1990 era VLBI system, doubly differenced ranging and dynamic model, a factor of 20 or better improvement can be expected in the TDRSS orbit determination accuracy. This would make the satellite-based delta-VLBI deep space navigation system more attractive than the other systems which have been proposed.
Directory of Open Access Journals (Sweden)
T. R. Sun
2012-08-01
Full Text Available We performed global MHD simulations of the geosynchronous magnetic field in response to fast solar wind dynamic pressure (Pd enhancements. Taking three Pd enhancement events in 2000 as examples, we found that the main features of the total field B and the dominant component Bz can be efficiently predicted by the MHD model. The predicted B and Bz varies with local time, with the highest level near noon and a slightly lower level around mid-night. However, it is more challenging to accurately predict the responses of the smaller component at the geosynchronous orbit (i.e., Bx and By. In contrast, the limitations of T01 model in predicting responses to fast Pd enhancements are presented.
Evolution of the Orbital Elements for Geosynchronous Orbit of Communications Satellite, II
Directory of Open Access Journals (Sweden)
Kyu-Hong Choi
1987-06-01
Full Text Available For a geostationary satellite north-south station keeping maneuver must control the inclination elements. The effects on the orbit plane of maneuvers and natural perturbations may be represented by a plane plot of Wc versus Ws, since these inclination elements represent the projection of the unit orbit normal onto the equatorial plane. The evolution of the semi-major axis and the inclination elements are obtained.
The local-time variation of the quiet plasmasphere: geosynchronous observations and kinetic theory
Directory of Open Access Journals (Sweden)
M. A. Reynolds
Full Text Available The quiet-time structure of the plasmaspheric density was investigated using observations of the Los Alamos geosynchronous satellites, and these observations were compared with theoretical predictions of the quasi-static local-time variation by a kinetic model. It was found that the coupling to the ionosphere (via the local-time variation of the exobase played a key role in determining the density structure at 6.6 R_{E} . The kinetic model predicts that most of the local-time variation at geosynchronous orbit is due to the variation of the exobase parameters. During quiet times, when the convection electric field is dominated by the corotation field, the effects due to flux-tube convection are less prominent than those due to the exobase variation. In addition, the kinetic model predicts that the geosynchronous plasmaspheric density level is at most only 25% of saturation density, even when geomagnetic activity is low. The low night-time densities of the ionospheric footpoints, and the subsequent long trapping time scales, prevent the equatorial densities from reaching saturation.
Key words. Magnetospheric physics (magnetosphere-ionosphere interactions; plasma convection; plasmasphere
The local-time variation of the quiet plasmasphere: geosynchronous observations and kinetic theory
Directory of Open Access Journals (Sweden)
M. A. Reynolds
2003-11-01
Full Text Available The quiet-time structure of the plasmaspheric density was investigated using observations of the Los Alamos geosynchronous satellites, and these observations were compared with theoretical predictions of the quasi-static local-time variation by a kinetic model. It was found that the coupling to the ionosphere (via the local-time variation of the exobase played a key role in determining the density structure at 6.6 RE . The kinetic model predicts that most of the local-time variation at geosynchronous orbit is due to the variation of the exobase parameters. During quiet times, when the convection electric field is dominated by the corotation field, the effects due to flux-tube convection are less prominent than those due to the exobase variation. In addition, the kinetic model predicts that the geosynchronous plasmaspheric density level is at most only 25% of saturation density, even when geomagnetic activity is low. The low night-time densities of the ionospheric footpoints, and the subsequent long trapping time scales, prevent the equatorial densities from reaching saturation.Key words. Magnetospheric physics (magnetosphere-ionosphere interactions; plasma convection; plasmasphere
Kinematically Decoupled Cores in Dwarf (Elliptical) Galaxies
Toloba, E.; Peletier, R. F.; Guhathakurta, P.; van de Ven, G.; Boissier, S.; Boselli, A.; Brok, M. d.; Falcón-Barroso, J.; Hensler, G.; Janz, J.; Laurikainen, E.; Lisker, T.; Paudel, S.; Ryś, A.; Salo, H.
An overview is given of what we know about the frequency of kinematically decoupled cores in dwarf elliptical galaxies. New observations show that kinematically decoupled cores happen just as often in dwarf elliptical as in ordinary early-type galaxies. This has important consequences for the
Spatial scan statistics using elliptic windows
DEFF Research Database (Denmark)
Christiansen, Lasse Engbo; Andersen, Jens Strodl; Wegener, Henrik Caspar
of confocal elliptic windows and propose a new way to present the information when a spatial point process is considered. This method gives smooth changes for smooth expansions of the set of clusters. A simulation study is used to show how the elliptic windows outperforms the usual circular windows...
Characterization of Elliptic Curve Traces under FR-reduction
Miyaji, Atsuko; Nakabayashi, Masaki; Takano, Shunzo
2001-01-01
Elliptic curve cryptosystems([19],[25]) are based on the elliptic curve discrete logarithm problem(ECDLP). If elliptic curve cryptosystems avoid FR-reduction([11],[17]) and anomalous elliptic curve over F_q ([34],[3],[36]), then with current knowledge we can construct elliptic curve cryptosystems over a smaller definition field. ECDLP has an interesting property that the security deeply depends on elliptic curve traces rather than definition fields, which does not occur in the case of the dis...
The elliptic genus and Hidden symmetry
International Nuclear Information System (INIS)
Jaffe, A.
2001-01-01
We study the elliptic genus (a partition function) in certain interacting, twist quantum field theories. Without twists, these theories have N=2 supersymmetry. The twists provide a regularization, and also partially break the supersymmetry. In spite of the regularization, one can establish a homotopy of the elliptic genus in a coupling parameter. Our construction relies on a priori estimates and other methods from constructive quantum field theory; this mathematical underpinning allows us to justify evaluating the elliptic genus at one endpoint of the homotopy. We obtain a version of Witten's proposed formula for the elliptic genus in terms of classical theta functions. As a consequence, the elliptic genus has a hidden SL(2,Z) symmetry characteristic of conformal theory, even though the underlying theory is not conformal. (orig.)
Locomotor Behavior of Chickens Anticipating Incline Walking
Directory of Open Access Journals (Sweden)
Chantal LeBlanc
2018-01-01
Full Text Available Keel bone damage (KBD is prevalent in hens raised for egg production, and ramps between different tiers in aviaries have potential to reduce the frequency of falls resulting in KBD. Effective use of ramps requires modulation of locomotion in anticipation of the incline. Inadequate adaptive locomotion may be one explanation why domestic layer hens (Gallus gallus domesticus exhibit high rates of KBD. To improve understanding of the capacity of hens to modulate their locomotion in anticipation of climbing, we measured the effects of incline angle upon the mechanics of the preparatory step before ascending a ramp. Because the energetic challenge of climbing increases with slope, we predicted that as angle of incline increased, birds during foot contact with the ground before starting to climb would increase their peak force and duration of contact and reduce variation in center of pressure (COP under their foot. We tested 20 female domestic chickens on ramp inclines at slopes of +0°, +40°, and +70° when birds were 17, 21, 26, 31, and 36 weeks of age. There were significantly higher vertical peak ground reaction forces in preparation at the steepest slope, and ground contact time increased significantly with each increase in ramp angle. Effects upon variation in COP were not apparent; likewise, effects of limb length, age, body mass were not significant. Our results reveal that domestic chickens are capable of modulating their locomotion in response to incline angle.
Euler characteristics and elliptic curves.
Coates, J; Howson, S
1997-10-14
Let E be a modular elliptic curve over [symbol, see text], without complex multiplication; let p be a prime number where E has good ordinary reduction; and let Finfinity be the field obtained by adjoining [symbol, see text] to all p-power division points on E. Write Ginfinity for the Galois group of Finfinity over [symbol, see text]. Assume that the complex L-series of E over [symbol, see text] does not vanish at s = 1. If p >/= 5, we make a precise conjecture about the value of the Ginfinity-Euler characteristic of the Selmer group of E over Finfinity. If one makes a standard conjecture about the behavior of this Selmer group as a module over the Iwasawa algebra, we are able to prove our conjecture. The crucial local calculations in the proof depend on recent joint work of the first author with R. Greenberg.
Inclined nanoimprinting lithography for 3D nanopatterning
International Nuclear Information System (INIS)
Liu Zhan; Bucknall, David G; Allen, Mark G
2011-01-01
We report a non-conventional shear-force-driven nanofabrication approach, inclined nanoimprint lithography (INIL), for producing 3D nanostructures of varying heights on planar substrates in a single imprinting step. Such 3D nanostructures are fabricated by exploiting polymer anisotropic dewetting where the degree of anisotropy can be controlled by the magnitude of the inclination angle. The feature size is reduced from micron scale of the template to a resultant nanoscale pattern. The underlying INIL mechanism is investigated both experimentally and theoretically. The results indicate that the shear force generated at a non-zero inclination angle induced by the INIL apparatus essentially leads to asymmetry in the polymer flow direction ultimately resulting in 3D nanopatterns with different heights. INIL removes the requirements in conventional nanolithography of either utilizing 3D templates or using multiple lithographic steps. This technique enables various 3D nanoscale devices including angle-resolved photonic and plasmonic crystals to be fabricated.
Breakwaters with Vertical and Inclined Concrete Walls
DEFF Research Database (Denmark)
Burcharth, Hans Falk
Following the PIANC PTC II working group on Analyses of Rubble Mound Breakwaters it was, in 1991, decided to form Working Group (WG) n° 28 on "Breakwaters with vertical and inclined concrete walls" The scope of the work was to achieve a better understanding of the overall safety aspects in the de......Following the PIANC PTC II working group on Analyses of Rubble Mound Breakwaters it was, in 1991, decided to form Working Group (WG) n° 28 on "Breakwaters with vertical and inclined concrete walls" The scope of the work was to achieve a better understanding of the overall safety aspects...
Modeling groundwater flow to elliptical lakes and through multi-aquifer elliptical inhomogeneities
Bakker, Mark
2004-05-01
Two new analytic element solutions are presented for steady flow problems with elliptical boundaries. The first solution concerns groundwater flow to shallow elliptical lakes with leaky lake beds in a single-aquifer. The second solution concerns groundwater flow through elliptical cylinder inhomogeneities in a multi-aquifer system. Both the transmissivity of each aquifer and the resistance of each leaky layer may differ between the inside and the outside of an inhomogeneity. The elliptical inhomogeneity may be bounded on top by a shallow elliptical lake with a leaky lake bed. Analytic element solutions are obtained for both problems through separation of variables of the Laplace and modified-Helmholtz differential equations in elliptical coordinates. The resulting equations for the discharge potential consist of infinite sums of products of exponentials, trigonometric functions, and modified-Mathieu functions. The series are truncated but still fulfill the differential equation exactly; boundary conditions are met approximately, but up to machine accuracy provided enough terms are used. The head and flow may be computed analytically at any point in the aquifer. Examples are given of uniform flow through an elliptical lake, a well pumping near two elliptical lakes, and uniform flow through three elliptical inhomogeneities in a multi-aquifer system. Mathieu functions may be applied in a similar fashion to solve other groundwater flow problems in semi-confined aquifers and leaky aquifer systems with elliptical internal or external boundaries.
International Workshop on Elliptic and Parabolic Equations
Schrohe, Elmar; Seiler, Jörg; Walker, Christoph
2015-01-01
This volume covers the latest research on elliptic and parabolic equations and originates from the international Workshop on Elliptic and Parabolic Equations, held September 10-12, 2013 at the Leibniz Universität Hannover. It represents a collection of refereed research papers and survey articles written by eminent scientist on advances in different fields of elliptic and parabolic partial differential equations, including singular Riemannian manifolds, spectral analysis on manifolds, nonlinear dispersive equations, Brownian motion and kernel estimates, Euler equations, porous medium type equations, pseudodifferential calculus, free boundary problems, and bifurcation analysis.
Internally cooled V-shape inclined monochromator
Czech Academy of Sciences Publication Activity Database
Oberta, Peter; Áč, V.; Hrdý, Jaromír
2008-01-01
Roč. 15, - (2008), 8-11 ISSN 0909-0495 R&D Projects: GA AV ČR IAA100100716 Grant - others:VEGA(SK) 1/4134/07 Institutional research plan: CEZ:AV0Z10100522 Keywords : inclined monochromator * heat load * internal cooling Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.333, year: 2008
A matter of chance, environment and inclination
Indian Academy of Sciences (India)
Lawrence
Why did I opt for science subjects in school, and choose a career in science? Perhaps the best answer would be. 'Chance, Environment and Inclination'. Here I am, considered to be a professional woman scien- tist, working towards understanding the biology of the malaria parasite and the challenges put up by the same.
Inclined test of nacelle wind lidar
DEFF Research Database (Denmark)
Courtney, Michael
A nacelle wind lidar, placed at ground level, is tested by inclining the laser beams to bisect a measurement mast at a known distance and height. The horizontal wind speed reported by the lidar is compared to a reference cup anemometer mounted on the mast at the comparison height....
Vehicle with inclinable caterpillar propulsion units
International Nuclear Information System (INIS)
Clar, G.
1991-01-01
This vehicle usable in hostile environment such nuclear industry has four propulsion units with a caterpillar track and two integrated motors: one for advancing the caterpillar track and the other for inclining the propulsion unit when overcoming obstacles. Each propulsion unit is easily replaceable because there are no mechanical parts in the body of the vehicle [fr
Heavy Flavour Electron Elliptic Flow
Gutierrez Ortiz, Nicolas Gilberto
Due to the large mass of the Charm and Beauty quarks, they are c reated in the very first moments of the ultra-high energy nucleus-nucleus collisions taking place at the CERN LHC, therefore, they should be unaware of the geome try of the colli- sion system and carry no azimuthal anisotropies. Similarly , the energy loss via gluon radiation for these massive quarks should be suppressed, th e so-called dead cone ef- fect. Although the observation of elliptic flow in the electro ns produced through the semileptonic decay of these heavy mesons is an indirect meas urement, throughout this thesis it will be shown that a strong correlation exists between the momentum anisotropy of the mother and daughter particles. In the low t ransverse momentum region such measurement would establish whether or not the s ystem reaches local thermal equilibrium. While at large transverse momentum, t he observation of collec- tivity for the heavy flavours can be understood only if the col lisional and radiative in-medium interaction...
Constructing elliptic curves from Galois representations
Snowden, Andrew; Tsimerman, Jacob
2017-01-01
Given a non-isotrivial elliptic curve over an arithmetic surface, one obtains a lisse $\\ell$-adic sheaf of rank two over the surface. This lisse sheaf has a number of straightforward properties: cyclotomic determinant, finite ramification, rational traces of Frobenius, and somewhere not potentially good reduction. We prove that any lisse sheaf of rank two possessing these properties comes from an elliptic curve.
The zero gravity curve and surface and radii for geostationary and geosynchronous satellite orbits
Directory of Open Access Journals (Sweden)
Sjöberg L.E.
2017-02-01
Full Text Available A geosynchronous satellite orbits the Earth along a constant longitude. A special case is the geostationary satellite that is located at a constant position above the equator. The ideal position of a geostationary satellite is at the level of zero gravity, i.e. at the geocentric radius where the gravitational force of the Earth equals the centrifugal force. These forces must be compensated for several perturbing forces, in particular for the lunisolar tides. Considering that the gravity field of the Earth varies not only radially but also laterally, this study focuses on the variations of zero gravity not only on the equator (for geostationary satellites but also for various latitudes. It is found that the radius of a geostationary satellite deviates from its mean value of 42164.2 km only within ±2 m, mainly due to the spherical harmonic coefficient J22, which is related with the equatorial flattening of the Earth. Away from the equator the zero gravity surface deviates from the ideal radius of a geosynchronous satellite, and more so for higher latitudes. While the radius of the former surface increases towards infinity towards the poles, the latter decreases about 520 m from the equator to the pole. Tidal effects vary these radii within ±2.3 km.
Kinematical and Dynamical Modeling of Elliptical Galaxies
Mamon, G. A.; Łokas, E.; Dekel, A.; Stoehr, F.; Cox, T. J.
Elements of kinematical and dynamical modeling of elliptical galaxies are presented. In projection, NFW models resemble Sérsic models, but with a very narrow range of shapes (m=3±1). The total density profile of ellipticals cannot be NFW-like because the predicted local M/L and aperture velocity dispersion within an effective radius (R_e) are much lower than observed. Stars must then dominate ellipticals out to a few R_e. Fitting an NFW model to the total density profile of Sérsic+NFW (stars+dark matter [DM]) ellipticals results in very high concentration parameters, as found by X-ray observers. Kinematical modeling of ellipticals assuming an isotropic NFW DM model underestimates M/L at the virial radius by a factor of 1.6 to 2.4, because dissipationless ΛCDM halos have slightly different density profiles and slightly radial velocity anisotropy. In N-body+gas simulations of ellipticals as merger remnants of spirals embedded in DM halos, the slope of the DM density profile is steeper when the initial spiral galaxies are gas-rich. The Hansen & Moore (2006) relation between anisotropy and the slope of the density profile breaks down for gas and DM, but the stars follow an analogous relation with slightly less radial anisotropies for a given density slope. Using kurtosis (h_4) to infer anisotropy in ellipticals is dangerous, as h4 is also sensitive to small levels of rotation. The stationary Jeans equation provides accurate masses out to 8 R_e. The discrepancy between the modeling of Romanowsky et al. (2003), indicating a dearth of DM in ellipticals, and the simulations analyzed by Dekel et al. (2005), which match the spectroscopic observations of ellipticals, is partly due to radial anisotropy and to observing oblate ellipticals face-on. However, one of the 15 solutions to the orbit modeling of Romanowsky et al. is found to have an amount and concentration of DM consistent with ΛCDM predictions.
Granular flow down a flexible inclined plane
Directory of Open Access Journals (Sweden)
Sonar Prasad
2017-01-01
Full Text Available Discrete and continuous systems are commonly studied individually, but seldom together. Indeed, granular flows are typically studied through flows over a rigid base. Here, we investigate the behaviour of granular flows over an inclined, flexible base. The flexible base is modeled as a rigid platform mounted on springs and has one degree of freedom. The base vibrations are introduced by the flow. We simulate such flows through a discrete element method and compare with experiments. We find that a flexible base increased the upper limit of the inclination up to which a steady flow is possible by at least 3 degrees. This stabilized zone may have important implications in applications such as conveyor belts and chutes.
Granular flow down a flexible inclined plane
Sonar, Prasad; Sharma, Ishan; Singh, Jayant
2017-06-01
Discrete and continuous systems are commonly studied individually, but seldom together. Indeed, granular flows are typically studied through flows over a rigid base. Here, we investigate the behaviour of granular flows over an inclined, flexible base. The flexible base is modeled as a rigid platform mounted on springs and has one degree of freedom. The base vibrations are introduced by the flow. We simulate such flows through a discrete element method and compare with experiments. We find that a flexible base increased the upper limit of the inclination up to which a steady flow is possible by at least 3 degrees. This stabilized zone may have important implications in applications such as conveyor belts and chutes.
Stress field of a dislocating inclined fault
Energy Technology Data Exchange (ETDEWEB)
Huang, F.; Wang, T.
1980-02-01
Analytical expressions are derived for the stress field caused by a rectangular dislocating fault of an arbitrary dip in a semi-infinite elastic medium for the case of unequal Lame constants. The results of computations for the stress fields on the ground surface of an inclined strike-slip and an inclined dip-slip fault are represented by contour maps. The effects of Poisson Ratio of the medium, the dip angle, upper and lower boundaries of the faults on the stress field at surface have been discussed. As an application, the contour maps for shear stress and hydrostatic stress of near fields of the Tonghai (1970), Haicheng (1975) and Tangshan (1976) earthquakes have been calculated and compared with the spatial distributions of strong aftershocks of these earthquakes. It is found that most of the strong aftershocks are distributed in the regions of tensional stress, where the hydrostatic stress is positive.
Stress field of a dislocating inclined fault
Energy Technology Data Exchange (ETDEWEB)
Huang, F.; Wang, T.
1980-02-01
In this paper, analytical expressions of the stress field given rise by a rectangular dislocating fault of an arbitrary dip in a semi-infinite elastic medium for the case of unequal Lame constants are derived. The results of computations for the stress fields on the ground surface of an inclined strike-slip and an inclined dip-slip fault are represented by contour maps. The effects of the Poisson Ratio of the medium, the dip angle, upper and lower boundaries of the faults on the stress field at the surface have been discussed. As an application, the contour maps for shear stress and hydrostatic stress of near fields of the Tonghai (1970), Haicheng, (1975) and Tangshan (1976) earthquakes have been calculated and compared with the spatial distributions of strong aftershocks of these earthquakes. It is found that most of the strong aftershocks are distributed in the regions of tensional stress where the hydrostatic stress is positive.
Bubble streams rising beneath an inclined surface
Bird, James; Brasz, Frederik; Kim, Dayoung; Menesses, Mark; Belden, Jesse
2017-11-01
Bubbles released beneath a submerged inclined surface can tumble along the wall as they rise, dragging the surrounding fluid with them. This effect has recently regained attention as a method to mitigate biofouling in marine environment, such as a ship hull. It appears that the efficacy of this approach may be related to the velocity of the rising bubbles and the extent that they spread laterally as they rise. Yet, it is unclear how bubble stream rise velocity and lateral migration depend on bubble size, flow rate, and inclination angle. Here we perform systematic experiments to quantify these relationships for both individual bubble trajectories and ensemble average statistics. Research supported by the Office of Naval Research under Grant Number award N00014-16-1-3000.
HIGH-INCLINATION ASTEROID FAMILIES V1.0
National Aeronautics and Space Administration — This data set contains the high-inclination asteroid families of Gil-Hutton (2006). A data set of 3652 high-inclination numbered asteroids was analyzed to search for...
Incisor inclination and perceived tooth colour changes.
Ciucchi, Philip; Kiliaridis, Stavros
2017-10-01
Social attractiveness is influenced by a variety of different smile-related factors. We evaluated whether the degree of upper central incisor proclination can result in tooth colour change. Forty young adult subjects (20-25 years) in good health with a complete sound dentition were selected. The subjects were seated in standardized light conditions with an above-directed light source. Their natural head position was stated as 0 degrees. To mimic the range of possible anterior torque movements they were asked to tilt their heads upward +15 degrees (upward tilting) and downward -15 degrees (downward tilting). Frontal macro photographs, parallel to the Frankfort plane of the patient's natural head position were taken at the three head angulations (+15, 0, and -15 degrees ). Photographs were analysed for colour differences at the centre of the incisor clinical crowns with a CIE L*a*b* colour model based software. A paired t-test was used to test for significance between each value for each inclination. Differences were found between the CIE L*a*b* colour values for: upward tilting, downward tilting, and -15 to +15 degrees (total tilting) except for b* values for downward tilting. As the inclination of the subject's head changed downward, the upper incisors were retroclined and the CIE L*a*b* values indicated a darker and less green but redder colour component. As the inclination of the subject's head changed upwards the upper incisors were proclined and the L*a*b* values indicated a lighter and less green and yellow but redder and bluer colour component. Proclination of upper incisors caused lighter tooth colour parameters compared to retroclined incisors and colour changes. Orthodontic change of upper incisor inclination may induce alterations on how tooth colour is perceived.
Tooth Wear Inclination in Great Ape Molars.
Knight-Sadler, Jordan; Fiorenza, Luca
2017-01-01
Primate dietary diversity is reflected in their dental morphology, with differences in size and shape of teeth. In particular, the tooth wear angle can provide insight into a species' ability to break down certain foods. To examine dietary and masticatory information, digitized polygon models of dental casts provide a basis for quantitative analysis of wear associated with tooth attrition. In this study, we analyze and compare the wear patterns of Pongo pygmaeus, Gorilla gorillagorilla and Pan troglodytes schweinfurthii lower molars, focusing on the degree of inclination of specific wear facets. The variation in wear angles appears to be indicative of jaw movements and the specific stresses imposed on food during mastication, reflecting thus the ecology of these species. Orangutans exhibit flatter wear angles, more typical of a diet consisting of hard and brittle foods, while gorillas show a wear pattern with a high degree of inclination, reflecting thus their more leafy diet. Chimpanzees, on the other hand, show intermediate inclinations, a pattern that could be related to their highly variable diet. This method is demonstrated to be a powerful tool for better understanding the relationship between food, mastication and tooth wear processes in living primates, and can be potentially used to reconstruct the diet of fossil species. © 2017 S. Karger AG, Basel.
A jumping cylinder in an incline
Gomez, Raul W.; Hernandez, Jorge; Marquina, Vivianne
2012-02-01
The problem of a cylinder of mass m and radius r, with its center of mass out of the cylinder axis, rolling in an incline that makes an angle α respect to the horizontal is analyzed. The equation of motion is solved to obtain the site where the cylinder loses contact with the incline (jumps). Several simplifications are made: the analyzed system consists of an homogeneous disc with a one dimensional straight line of mass parallel to the disc axis at a distance d Styrofoam cylinder of radius r = 10.0 ± 0.05 cm, high h = 5.55 ± 0.05 cm and a mass m1 = 24.45 ± 0.05 g, to which a 9.50 ± 0.01 mm diameter and 5.10 ± 0.001 cm long brass road of mass m2 = 30.75 ± 0.05 g was imbibed parallel to the disc axis at a distance of 5.40 ± 0.05 cm from it. Then the disc rolls on a 3.20 m long wooden ramp inclined at 30 and 45 respect to the horizontal. To determine the jumping site, the movements were recorded with a high-speed video camera (Casio EX ZR100) at 400 frames per second. The experimental results agree well with the theoretical predictions.
Precession of a Spinning Ball Rolling down an Inclined Plane
Cross, Rod
2015-01-01
A routine problem in an introductory physics course considers a rectangular block at rest on a plane inclined at angle a to the horizontal. In order for the block not to slide down the incline, the coefficient of sliding friction, µ, must be at least tan a. The situation is similar for the case of a ball rolling down an inclined plane. In order…
Pool Boiling CHF in Inclined Narrow Annuli
International Nuclear Information System (INIS)
Kang, Myeong Gie
2010-01-01
Pool boiling heat transfer has been studied extensively since it is frequently encountered in various heat transfer equipment. Recently, it has been widely investigated in nuclear power plants for application to the advanced light water reactors designs. Through the review on the published results it can be concluded that knowledge on the combined effects of the surface orientation and a confined space on pool boiling heat transfer is of great practical importance and also of great academic interest. Fujita et al. investigated pool boiling heat transfer, from boiling inception to the critical heat flux (CHF, q' CHF ), in a confined narrow space between heated and unheated parallel rectangular plates. They identified that both the confined space and the surface orientation changed heat transfer much. Kim and Suh changed the surface orientation angles of a downward heating rectangular channel having a narrow gap from the downward-facing position (180 .deg.) to the vertical position (90 .deg.). They observed that the CHF generally decreased as the inclination angle (θ ) increased. Yao and Chang studied pool boiling heat transfer in a confined heat transfer for vertical narrow annuli with closed bottoms. They observed that when the gap size ( s ) of the annulus was decreased the effect of space confinement to boiling heat transfer increased. The CHF was occurred at much lower value for the confined space comparing to the unconfined pool boiling. Pool boiling heat transfer in narrow horizontal annular crevices was studied by Hung and Yao. They concluded that the CHF decreased with decreasing gap size of the annuli and described the importance of the thin film evaporation to explain the lower CHF of narrow crevices. The effect of the inclination angle on the CHF on countercurrent boiling in an inclined uniformly heated tube with closed bottoms was also studied by Liu et al. They concluded that the CHF reduced with the inclination angle decrease. A study was carried out
The Fundamental Relations of Elliptical Galaxies
Guzman, R.; Lucey, J. R.; Bower, R. G.
1993-12-01
We investigate the basic laws that determine the global structure and metal abundance of elliptical galaxies. The existence of the Fundamental Plane has been considered to imply that the virial theorem is the only structural constraint for giant ellipticals. However, we show that giant ellipticals do not uniformly cover the Fundamental Plane, but are located in a band which is not the result of selection effects. This `Fundamental Band' implies a second constraint between scalelength and galaxy mass. On the basis of this result, we present a new framework in which the structure and metal abundance of giant ellipticals are determined by only three fundamental relations: M is proportional to R, M is proportional to Rzeta^ and Z is proportional to xi where M is the galaxy mass, R is the half-mass radius, is the mean square speed of the system's stars and Z is the average metallicity of the stellar population; ζ and ξ are constants. ξ is uniquely determined from the observations. The value of ζ, however, depends on the assumed scaling laws that relate M and R to the observed luminosity and half-light radius. We assume M/L is proportional to Meta^ and R/R_e_ is proportional to Mlambda^. The two constants η and λ are mutually constrained by observations, but their values are not uniquely determined. All the wide variety of observed global correlations can be derived as simple combinations of these fundamental relations. This simple framework provides new insights into the intrinsic differences between giant and dwarf ellipticals. The observed universality of the luminosity- and metallicity-velocity dispersion correlations strongly suggests a simple solution within our framework in which ξ, ζ and η adopt the same values for both dwarf and giant ellipticals. In this case, we show that the dependence of R/R_e_ on galaxy mass is the only difference between the two galaxy families. We compare this framework with a theoretical scenario of galaxy formation that
Ultraluminous Infrared Mergers: Elliptical Galaxies in Formation?
Genzel, R.; Tacconi, L. J.; Rigopoulou, D.; Lutz, D.; Tecza, M.
2001-12-01
We report high-quality near-IR spectroscopy of 12 ultraluminous infrared galaxy mergers (ULIRGs). Our new VLT and Keck data provide ~0.5" resolution, stellar and gas kinematics of these galaxies, most of which are compact systems in the last merger stages. We confirm that ULIRG mergers are ``ellipticals in formation.'' Random motions dominate their stellar dynamics, but significant rotation is common. Gasdynamics and stellar dynamics are decoupled in most systems. ULIRGs fall on or near the fundamental plane of hot stellar systems, and especially on its less evolution-sensitive, reff-σ projection. The ULIRG velocity dispersion distribution, their location in the fundamental plane, and their distribution of vrotsini/σ closely resemble those of intermediate-mass (~L*), elliptical galaxies with moderate rotation. As a group ULIRGs do not resemble giant ellipticals with large cores and little rotation. Our results are in good agreement with other recent studies indicating that disky ellipticals with compact cores or cusps can form through dissipative mergers of gas-rich disk galaxies while giant ellipticals with large cores have a different formation history. Based on observations at the European Southern Observatory, Chile (ESO 65.N-0266, 65.N-0289), and on observations at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, The University of California, and the National Aeronautics and Space Administration. The Keck Observatory was made possible by the general financial support by the W. M. Keck Foundation.
Hot interstellar matter in elliptical galaxies
Kim, Dong-Woo
2012-01-01
Based on a number of new discoveries resulting from 10 years of Chandra and XMM-Newton observations and corresponding theoretical works, this is the first book to address significant progress in the research of the Hot Interstellar Matter in Elliptical Galaxies. A fundamental understanding of the physical properties of the hot ISM in elliptical galaxies is critical, because they are directly related to the formation and evolution of elliptical galaxies via star formation episodes, environmental effects such as stripping, infall, and mergers, and the growth of super-massive black holes. Thanks to the outstanding spatial resolution of Chandra and the large collecting area of XMM-Newton, various fine structures of the hot gas have been imaged in detail and key physical quantities have been accurately measured, allowing theoretical interpretations/predictions to be compared and tested against observational results. This book will bring all readers up-to-date on this essential field of research.
Nonlinear elliptic equations of the second order
Han, Qing
2016-01-01
Nonlinear elliptic differential equations are a diverse subject with important applications to the physical and social sciences and engineering. They also arise naturally in geometry. In particular, much of the progress in the area in the twentieth century was driven by geometric applications, from the Bernstein problem to the existence of Kähler-Einstein metrics. This book, designed as a textbook, provides a detailed discussion of the Dirichlet problems for quasilinear and fully nonlinear elliptic differential equations of the second order with an emphasis on mean curvature equations and on Monge-Ampère equations. It gives a user-friendly introduction to the theory of nonlinear elliptic equations with special attention given to basic results and the most important techniques. Rather than presenting the topics in their full generality, the book aims at providing self-contained, clear, and "elementary" proofs for results in important special cases. This book will serve as a valuable resource for graduate stu...
Elliptical cross section fuel rod study II
International Nuclear Information System (INIS)
Taboada, H.; Marajofsky, A.
1996-01-01
In this paper it is continued the behavior analysis and comparison between cylindrical fuel rods of circular and elliptical cross sections. Taking into account the accepted models in the literature, the fission gas swelling and release were studied. An analytical comparison between both kinds of rod reveals a sensible gas release reduction in the elliptical case, a 50% swelling reduction due to intragranular bubble coalescence mechanism and an important swelling increase due to migration bubble mechanism. From the safety operation point of view, for the same linear power, an elliptical cross section rod is favored by lower central temperatures, lower gas release rates, greater gas store in ceramic matrix and lower stored energy rates. (author). 6 refs., 8 figs., 1 tab
Diffuse Stellar Substructure in Virgo Ellipticals
Mihos, Chris; Janowiecki, S.; Harding, P.; Feldmeier, J.; Rudick, C.; Morrison, H.
2010-01-01
As part of our deep wide-field imaging survey of the Virgo Cluster, we have studied in detail the extended stellar halos of the five bright Virgo ellipticals M49, M87, M86, M84, and M89. We examine substructure in these halos by fitting and subtracting elliptical isophotal models out to large radius and low surface brightness (r>100 kpc and muV 28). After subtraction of these isophotal models, these elliptical galaxies show a variety of diffuse structures, from extended stellar streams to complex systems of shells and loops. These features give insight into the accretion history of these galaxies and their dynamical history in the Virgo Cluster. This work has been supported by the National Science Foundation.
Impact of slope inclination on salt accumulation
Nachshon, Uri
2017-04-01
Field measurements indicated on high variability in salt accumulation along natural and cultivated slopes, even for relatively homogeneous soil conditions. It was hypothesised that slope inclination has an impact on the location of salt accumulation along the slope. A set of laboratory experiments and numerical models were used to explore the impact of slope inclination on salt accumulation. It was shown, experimentally, that for conditions of saline water source at the lower boundary of the slope - salt accumulates in low concentrations and homogeneously along the entire slope, for moderate slopes. However, as inclination increases high salt concentrations were observed at the upper parts of the slope, leaving the lower parts of the slope relatively free of salt. The traditional flow and transport models did not predict the experimental observations as they indicated also for the moderate slopes on salt accumulation in the elevated parts of the slope, away of the saline water source. Consequently - a conceptual model was raised to explain the laboratory observations. It was suggested that the interactions between slope angle, evaporation rates, hydraulic conductivity of the medium and distribution of wetness along the slope affect the saline water flow path through the medium. This lead to preferential flow path close to the soil-atmosphere interface for the steep slopes, which leads to constant wash of the salts from the evaporation front upward towards the slope upper parts, whereas for the moderate slopes, flow path is below the soil-atmosphere interface, therefore salt that accumulates at the evaporation front is not being transported upward. Understanding of salt dynamics along slopes is important for agricultural and natural environments, as well as for civil engineering purposes. Better understanding of the salt transport processes along slopes will improve our ability to minimize and to cope with soil salinization processes. The laboratory experiments and
Inclined solar chimney for power production
Energy Technology Data Exchange (ETDEWEB)
Panse, S.V., E-mail: sudhirpanse@yahoo.com [Institute of Chemical Technology, Matunga, Mumbai 400 019 (India); Jadhav, A.S.; Gudekar, A.S. [Institute of Chemical Technology, Matunga, Mumbai 400 019 (India); Joshi, J.B. [Institute of Chemical Technology, Matunga, Mumbai 400 019 (India); Homi Bhabha National Institute, Trombay, Mumbai 400 094 (India)
2011-09-15
Highlights: {yields} Solar energy harnessing using inclined face of high mountains as solar chimney. {yields} Solar chimneys with structural stability, ease of construction and lower cost. {yields} Mathematical model developed, using complete (mechanical and thermal) energy balance. {yields} Can harness wind power also, as wind velocities at mountain top add to power output. {yields} Air temperature and velocity increase, as air rises in inclined chimney. - Abstract: The present concept of solar chimney is a tall vertical chimney constructed at the center of a large area, which is the collector. This creates questions about stability and economic viability of the chimney and also demands elaborate engineering techniques for constructing a tall chimney. We suggest geometry of 'Inclined Solar Chimney' (ISC), which is constructed along the face of a high rising mountain, on which maximum solar insolation is incident throughout the year. The chimney and the collector get merged here. This makes the structure stable, cost effective and easy for construction. A mathematical model has been developed considering the total energy balance. It predicts the temperature and velocity and kinetic power of the emerging air draft for some chosen values of other parameters. The model also shows the proportion in which absorbed solar energy is divided into different forms, and hence predicts the dependence of kinetic of emerging air draft upon dimensions of the chimney and properties of materials used. Further, it is shown that external winds enhance the kinetic power of the emerging air. Thus ISC can also harness the wind energy, available at the top of the mountain.
Characterization of the Geosynchronous Plasma Environment for the SENSER/RROE Optical Instrument
Energy Technology Data Exchange (ETDEWEB)
Woodroffe, Jesse Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-11-08
In this report, we summarize available research in order to characterize expected rates of particle incidence on the SENSER/RROE optical instrument. We first investigate the “normal” background levels using data from statistical studies of spacecraft in geosynchronous orbit and empirical models. We then consider “worst case” scenarios based on event studies in which extreme fluxes have been observed. We use these data to define “maximum” rates of particle incidence. We then consider how incident particles will actually produce counts in the instrument by considering the effects of screening by the instrument housing and the possibility of direct particle access to the housing, with rates for both primary access and secondary electron generation.
Reaping the space investment. [Shuttle era geosynchronous satellite based technological trends
Calio, A. J.
1979-01-01
By 1999 operational space systems will be implemented routinely on a worldwide scale in many areas vital to human survival and life quality. Geosynchronous-based monitoring and observation will be extensively used. The Shuttle era will bring in the capability to allow monitoring and identifying pollution sources which fail to stay within required limits. Remotely sensed data over land masses will provide needed facts on renewable and nonrenewable earth resources. New instruments and techniques will have been developed to provide geologists with clues to the declining number of deposits of fuels and minerals. Also, practical methods for predicting earthquakes will have been elaborated by 1999. Communications will see implementation of many of the technological goals of 1978.
Goldenberg, Stanley B.; Houze, Robert A., Jr.; Churchill, Dean D.
1990-01-01
The horizontal precipitation structure of cloud clusters observed over the South China Sea during the Winter Monsoon Experiment (WMONEX) is analyzed using a convective-stratiform technique (CST) developed by Adler and Negri (1988). The technique was modified by altering the method for identifying convective cells in the satellite data, accounting for the extremely cold cloud tops characteristic of the WMONEX region, and modifying the threshold infrared temperature for the boundary of the stratiform rain area. The precipitation analysis was extended to the entire history of the cloud cluster by applying the modified CST to IR imagery from geosynchronous-satellite observations. The ship and aircraft data from the later period of the cluster's lifetime make it possible to check the locations of convective and stratiform precipitation identified by the CST using in situ observations. The extended CST is considered to be effective for determining the climatology of the convective-stratiform structure of tropical cloud clusters.
Electromagnetic Invisibility of Elliptic Cylinder Cloaks
International Nuclear Information System (INIS)
Kan, Yao; Chao, Li; Fang, Li
2008-01-01
Structures with unique electromagnetic properties are designed based on the approach of spatial coordinate transformations of Maxwell's equations. This approach is applied to scheme out invisible elliptic cylinder cloaks, which provide more feasibility for cloaking arbitrarily shaped objects. The transformation expressions for the anisotropic material parameters and the field distribution are derived. The cloaking performances of ideal and lossy elliptic cylinder cloaks are investigated by finite element simulations. It is found that the cloaking performance will degrade in the forward direction with increasing loss. (fundamental areas of phenomenology (including applications))
Elliptic Tales Curves, Counting, and Number Theory
Ash, Avner
2012-01-01
Elliptic Tales describes the latest developments in number theory by looking at one of the most exciting unsolved problems in contemporary mathematics--the Birch and Swinnerton-Dyer Conjecture. The Clay Mathematics Institute is offering a prize of 1 million to anyone who can discover a general solution to the problem. In this book, Avner Ash and Robert Gross guide readers through the mathematics they need to understand this captivating problem. The key to the conjecture lies in elliptic curves, which are cubic equations in two variables. These equations may appear simple, yet they arise from
Elliptical Particle Clustering in Cellular Flows
Atis, Severine; Sapsis, Themistoklis; Peacock, Thomas
2015-11-01
The transport of finite-sized objects by fluid flows is relevant to a wide variety of phenomena, such as debris transport on the ocean surface or bacteria advection in fluid environment. The shape of the advected objects can strongly alter their coupling with the surrounding flow field, and hence, greatly affecting their dispersion by the flow. We present the results of investigations of the behavior of neutrally buoyant, elliptical particles in two-dimensional cellular flows. We find that their trajectories, and overall organization, are markedly different than for spherical particles, with clear clustering for the elliptical particles associated with vortices.
Dense, layered, inclined flows of spheres
Jenkins, James T.; Larcher, Michele
2017-12-01
We consider dense, inclined flows of spheres in which the particles translate in layers, whose existence may be promoted by the presence of a rigid base and/or sidewalls. We imagine that in such flows a sphere of a layer is forced up the back of a sphere of the layer below, lifting a column of spheres above it, and then falls down the front of the lower sphere, until it bumps against the preceding sphere of the lower layer. We calculate the forces and rate of momentum transfer associated with this process of rub, lift, fall, and bump and determine a relation between the ratio of shear stress to normal stress and the rate of strain that may be integrated to obtain the velocity profile. The fall of a sphere and that of the column above it results in a linear increase in the magnitude of the velocity fluctuations with distance from the base of the flow. We compare the predictions of the model with measured profiles of velocity and granular temperature in several different dense, inclined flows.
Quasi-Rayleigh waves in transversely isotropic half-space with inclined axis of symmetry
International Nuclear Information System (INIS)
Yanovskaya, T.B.; Savina, L.S.
2003-09-01
A method for determination of characteristics of quasi-Rayleigh (qR) wave in a transversely isotropic homogeneous half-space with inclined axis of symmetry is outlined. The solution is obtained as a superposition of qP, qSV and qSH waves, and surface wave velocity is determined from the boundary conditions at the free surface and at infinity, as in the case of Rayleigh wave in isotropic half-space. Though the theory is simple enough, a numerical procedure for the calculation of surface wave velocity presents some difficulties. The difficulty is conditioned by necessity to calculate complex roots of a non-linear equation, which in turn contains functions determined as roots of nonlinear equations with complex coefficients. Numerical analysis shows that roots of the equation corresponding to the boundary conditions do not exist in the whole domain of azimuths and inclinations of the symmetry axis. The domain of existence of qR wave depends on the ratio of the elastic parameters: for some strongly anisotropic models the wave cannot exist at all. For some angles of inclination qR wave velocities deviate from those calculated on the basis of the perturbation method valid for weak anisotropy, though they have the same tendency of variation with azimuth. The phase of qR wave varies with depth unlike Rayleigh wave in isotropic half-space. Unlike Rayleigh wave in isotropic half-space, qR wave has three components - vertical, radial and transverse. Particle motion in horizontal plane is elliptic. Direction of the major axis of the ellipsis coincide with the direction of propagation only in azimuths 0 deg. (180 deg.) and 90 deg. (270 deg.). (author)
Elliptic genus of phases of N=2 theories
Libgober, A.
2014-01-01
We discuss an algebro-geometric description of Witten's phases of N=2 theories and propose a definition of their elliptic genus provided some conditions on singularities of the phases are met. For Landau-Ginzburg phase one recovers elliptic genus of LG models proposed in physics literature in early 90s. For certain transitions between phases we derive invariance of elliptic genus from an equivariant form of McKay correspondence for elliptic genus. As special cases one obtains Landau-Giznburg/...
Elliptic genus of singular algebraic varieties and quotients
Libgober, Anatoly
2018-02-01
This paper discusses the basic properties of various versions of the two-variable elliptic genus with special attention to the equivariant elliptic genus. The main applications are to the elliptic genera attached to non-compact GITs, including the theories regarding the elliptic genera of phases on N = 2 introduced in Witten (1993 Nucl. Phys. B 403 159-222).
Carleman estimates for some elliptic systems
International Nuclear Information System (INIS)
Eller, M
2008-01-01
A Carleman estimate for a certain first order elliptic system is proved. The proof is elementary and does not rely on pseudo-differential calculus. This estimate is used to prove Carleman estimates for the isotropic Lame system as well as for the isotropic Maxwell system with C 1 coefficients
Elliptic genera from multi-centers
Gaddam, Nava
2016-01-01
I show how elliptic genera for various Calabi-Yau threefolds may be understood from supergravity localization using the quantization of the phase space of certain multi-center configurations. I present a simple procedure that allows for the enumeration of all multi-center configurations contributing
Nonlinear elliptic differential equations with multivalued nonlinearities
Indian Academy of Sciences (India)
Springer Verlag Heidelberg #4 2048 1996 Dec 15 10:16:45
Nonlinear elliptic differential equations with multivalued ... has a solution. Finally in the last part we consider an eigenvalue problem with a nonmonotone multivalued nonlinearity. Using the critical point theory for nonsmooth .... A is upper semicontinuous (as a set-valued map) from every finite dimensional subspace of X into ...
Impedances in lossy elliptical vacuum chambers
International Nuclear Information System (INIS)
Piwinski, A.
1994-04-01
The wake fields of a bunched beam caused by the resistivity of the chamber walls are investigated for a vacuum chamber with elliptical cross section. The longitudinal and transverse impedances are calculated for arbitrary energies and for an arbitrary position of the beam in the chamber. (orig.)
Quasilinear infiltration from an elliptical cavity
Kuhlman, Kristopher L.; Warrick, Arthur W.
2008-08-01
We develop analytic solutions to the linearized steady-state Richards equation for head and total flowrate due to an elliptic cylinder cavity with a specified pressure head boundary condition. They are generalizations of the circular cylinder cavity solutions of Philip [Philip JR. Steady infiltration from circular cylindrical cavities. Soil Sci Soc Am J 1984;48:270-8]. The circular and strip sources are limiting cases of the elliptical cylinder solution, derived for both horizontally- and vertically-aligned ellipses. We give approximate rational polynomial expressions for total flowrate from an elliptical cylinder over a range of sizes and shapes. The exact elliptical solution is in terms of Mathieu functions, which themselves are generalizations of and computed from trigonometric and Bessel functions. The required Mathieu functions are computed from a matrix eigenvector problem, a modern approach that is straightforward to implement using available linear algebra libraries. Although less efficient and potentially less accurate than the iterative continued fraction approach, the matrix approach is simpler to understand and implement and is valid over a wider parameter range.
A Mean Value Formula for Elliptic Curves
Directory of Open Access Journals (Sweden)
Rongquan Feng
2014-01-01
Full Text Available It is proved in this paper that, for any point on an elliptic curve, the mean value of x-coordinates of its n-division points is the same as its x-coordinate and that of y-coordinates of its n-division points is n times that of its y-coordinate.
Spectral Curves of Operators with Elliptic Coefficients
Directory of Open Access Journals (Sweden)
J. Chris Eilbeck
2007-03-01
Full Text Available A computer-algebra aided method is carried out, for determining geometric objects associated to differential operators that satisfy the elliptic ansatz. This results in examples of Lamé curves with double reduction and in the explicit reduction of the theta function of a Halphen curve.
Limits of functions and elliptic operators
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
Our motivation is that in many geometric situations rigidity phenomena are associated with elliptic operators which are often hidden, i.e., not a priori related to the geometry. Two striking instances of this are the Seiberg–Witten equations for smooth four-dimensional manifolds and J-holomorphic curves in Symplectic topology ...
Abundance Ratios in Dwarf Elliptical Galaxies
Sen, Seyda; Peletier, Reynier F.; Toloba, Elisa; Mentz, Jaco J.
The aim of this study is to determine abundance ratios and star formation histories (SFH) of dwarf ellipticals in the nearby Virgo cluster. We perform a stellar population analysis of 39 dEs and study them using index-index and scaling relations. We find an unusual behaviour where [Na/Fe] is
Spatial scan statistics using elliptic windows
DEFF Research Database (Denmark)
Christiansen, Lasse Engbo; Andersen, Jens Strodl; Wegener, Henrik Caspar
2006-01-01
windows and propose a new way to present the information when a spatial point process is considered. This method gives smooth changes for smooth expansions of the set of clusters. A simulation study is used to show how the elliptic windows outperforms the usual circular windows. The proposed method...
On the space of elliptic genera
Manschot, J.
2008-01-01
Invariance under modular transformations and spectral flow restrict the possible spectra of superconformal field theories (SCFT). This paper presents a technique to calculate the number of constraints on the polar spectra of N=(2,2) and N=(4,0) SCFT's by analyzing the elliptic genus. The polar
The invertible double of elliptic operators
DEFF Research Database (Denmark)
Booss-Bavnbek, Bernhelm; Lesch, Matthias; Zhu, Chaofeng
We construct a canonical invertible double for general first order elliptic differential operators over smooth compact manifolds with boundary and derive a natural formula for the Calderon projector which yields a generalization of the famous Cobordism Theorem. Assuming symmetric principal symbol...
Elliptic genera from multi-centers
Energy Technology Data Exchange (ETDEWEB)
Gaddam, Nava [Institute for Theoretical Physics and Center for Extreme Matter and Emergent Phenomena,Utrecht University, 3508 TD Utrecht (Netherlands)
2016-05-13
I show how elliptic genera for various Calabi-Yau threefolds may be understood from supergravity localization using the quantization of the phase space of certain multi-center configurations. I present a simple procedure that allows for the enumeration of all multi-center configurations contributing to the polar sector of the elliptic genera — explicitly verifying this in the cases of the quintic in ℙ{sup 4}, the sextic in Wℙ{sub (2,1,1,1,1)}, the octic in Wℙ{sub (4,1,1,1,1)} and the dectic in Wℙ{sub (5,2,1,1,1)}. With an input of the corresponding ‘single-center’ indices (Donaldson-Thomas invariants), the polar terms have been known to determine the elliptic genera completely. I argue that this multi-center approach to the low-lying spectrum of the elliptic genera is a stepping stone towards an understanding of the exact microscopic states that contribute to supersymmetric single center black hole entropy in N=2 supergravity.
Systematics of elliptic flow in heavy-ion collisions
Indian Academy of Sciences (India)
Abstract. We analyze elliptic flow from SIS to RHIC energies systematically in a realistic dy- namical cascade model. We compare our results with the recent data from STAR and PHOBOS collaborations on elliptic flow of charged particles at midrapidity in Au·Au collisions at RHIC. In the analysis of elliptic flow at RHIC energy ...
Systematics of elliptic flow in heavy-ion collisions
Indian Academy of Sciences (India)
We analyze elliptic ﬂow from SIS to RHIC energies systematically in a realistic dynamical cascade model. We compare our results with the recent data from STAR and PHOBOS collaborations on elliptic ﬂow of charged particles at midrapidity in Au + Au collisions at RHIC. In the analysis of elliptic ﬂow at RHIC energy, we ﬁnd ...
Djidel, S.; Bouamar, M.; Khedrouche, D.
2016-04-01
This paper presents a performances study of UWB monopole antenna using half-elliptic radiator conformed on elliptical surface. The proposed antenna, simulated using microwave studio computer CST and High frequency simulator structure HFSS, is designed to operate in frequency interval over 3.1 to 40 GHz. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. The proposed antenna structure is suitable for ultra-wideband applications, which is, required for many wearable electronics applications.
Directory of Open Access Journals (Sweden)
Dmitri Talalaev
2009-12-01
Full Text Available In this paper we construct the quantum spectral curve for the quantum dynamical elliptic gl_n Gaudin model. We realize it considering a commutative family corresponding to the Felder's elliptic quantum group E_{τ,h}(gl_n and taking the appropriate limit. The approach of Manin matrices here suits well to the problem of constructing the generation function of commuting elements which plays an important role in SoV and Langlands concept.
Study of Zernike polynomials of an elliptical aperture obscured with an elliptical obscuration.
Hasan, Sundus Y; Shaker, Ali S
2012-12-10
In this research, Zernike polynomials for a unit annular elliptical aperture (ellipse inscribed by a unit circle of unit radius obscured by elliptical obscuration) have been studied in Cartesian coordinates and in polar coordinates. These polynomials have been shown to form a complete basis orthogonal on a unit annular ellipse aperture, and they represent balanced classical aberrations just as Zernike circular polynomials in a unit circle.
On liquid films on an inclined plate
BENILOV, E. S.
2010-08-18
This paper examines two related problems from liquid-film theory. Firstly, a steady-state flow of a liquid film down a pre-wetted plate is considered, in which there is a precursor film in front of the main film. Assuming the former to be thin, a full asymptotic description of the problem is developed and simple analytical estimates for the extent and depth of the precursor film\\'s influence on the main film are provided. Secondly, the so-called drag-out problem is considered, where an inclined plate is withdrawn from a pool of liquid. Using a combination of numerical and asymptotic means, the parameter range where the classical Landau-Levich-Wilson solution is not unique is determined. © 2010 Cambridge University Press.
Granular flow over inclined channels with constrictions
Tunuguntla, Deepak; Weinhart, Thomas; Thornton, Anthony; Bokhove, Onno
2013-04-01
Study of granular flows down inclined channels is essential in understanding the dynamics of natural grain flows like landslides and snow avalanches. As a stepping stone, dry granular flow over an inclined channel with a localised constriction is investigated using both continuum methods and particle simulations. Initially, depth-averaged equations of motion (Savage & Hutter 1989) containing an unknown friction law are considered. The shallow-layer model for granular flows is closed with a friction law obtained from particle simulations of steady flows (Weinhart et al. 2012) undertaken in the open source package Mercury DPM (Mercury 2010). The closed two-dimensional (2D) shallow-layer model is then width-averaged to obtain a novel one-dimensional (1D) model which is an extension of the one for water flows through contraction (Akers & Bokhove 2008). Different flow states are predicted by this novel one-dimensional theory. Flow regimes with distinct flow states are determined as a function of upstream channel Froude number, F, and channel width ratio, Bc. The latter being the ratio of the channel exit width and upstream channel width. Existence of multiple steady states is predicted in a certain regime of F - Bc parameter plane which is in agreement with experiments previously undertaken by (Akers & Bokhove 2008) and for granular flows (Vreman et al. 2007). Furthermore, the 1D model is verified by solving the 2D shallow granular equations using an open source discontinuous Galerkin finite element package hpGEM (Pesch et al. 2007). For supercritical flows i.e. F > 1 the 1D asymptotics holds although the two-dimensional oblique granular jumps largely vary across the converging channel. This computationally efficient closed 1D model is validated by comparing it to the computationally more expensiveaa three-dimensional particle simulations. Finally, we aim to present a quasi-steady particle simulation of inclined flow through two rectangular blocks separated by a gap
Inclined Buildings – Some Reasons and Solutions
Kijanka, Małgorzata; Kowalska, Magdalena
2017-10-01
To straighten a leaning building is never easy. There are no standard solutions. On the other hand, there are several, usually historical, leaning structures which have not been rectified, mostly because in the current shape they are a touristic attraction - the best example being the famous Leaning Tower of Pisa. This does not mean however that inclination of load bearing walls can be ignored. Even though in some cases the problem can be treated in terms of serviceability limit states (the deformation is only decreasing the comfort of ‘normal use’ of the building), in the other – it may be a signal of the forthcoming structural failure. The situation must always be treated individually – if the problem concerns a residential building, then cracks on the walls, not-opening doors or tilted ceilings, which often coincide with the leaning of the external walls, are always the reason of worry and such a building needs to be straightened. The reasons of the problem lie usually in uneven settlement of the ground, which in turn, may be caused by various problems, such as the presence of too soft, too weak, unconsolidated or expansive soils under the building, varying groundwater table, mining activity etc. Solving of the problem by just straightening the building is often not enough. To prevent further deformations a detailed analysis of the possible causes is necessary. Sometimes it may be helpful to review similar cases. The paper contains a general overview of selected inclined buildings: starting with the well-known historical examples and ending with individual houses from the Region of Silesia. Since the problem of instability mostly affects structures with critical height to width ratio, tall and narrow structures (towers) are dominating in the work. The aim of the study was to describe the reasons of the problems and present solutions that have been successfully applied and can be also useful to engineers and designers to prevent similar situations.
Impinging Water Droplets on Inclined Glass Surfaces
Energy Technology Data Exchange (ETDEWEB)
Armijo, Kenneth Miguel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lance, Blake [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ho, Clifford K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2017-09-01
Multiphase computational models and tests of falling water droplets on inclined glass surfaces were developed to investigate the physics of impingement and potential of these droplets to self-clean glass surfaces for photovoltaic modules and heliostats. A multiphase volume-of-fluid model was developed in ANSYS Fluent to simulate the impinging droplets. The simulations considered different droplet sizes (1 mm and 3 mm), tilt angles (0°, 10°, and 45°), droplet velocities (1 m/s and 3 m/s), and wetting characteristics (wetting=47° contact angle and non-wetting = 93° contact angle). Results showed that the spread factor (maximum droplet diameter during impact divided by the initial droplet diameter) decreased with increasing inclination angle due to the reduced normal force on the surface. The hydrophilic surface yielded greater spread factors than the hydrophobic surface in all cases. With regard to impact forces, the greater surface tilt angles yielded lower normal forces, but higher shear forces. Experiments showed that the experimentally observed spread factor (maximum droplet diameter during impact divided by the initial droplet diameter) was significantly larger than the simulated spread factor. Observed spread factors were on the order of 5 - 6 for droplet velocities of ~3 m/s, whereas the simulated spread factors were on the order of 2. Droplets were observed to be mobile following impact only for the cases with 45° tilt angle, which matched the simulations. An interesting phenomenon that was observed was that shortly after being released from the nozzle, the water droplet oscillated (like a trampoline) due to the "snapback" caused by the surface tension of the water droplet being released from the nozzle. This oscillation impacted the velocity immediately after the release. Future work should evaluate the impact of parameters such as tilt angle and surface wettability on the impact of particle/soiling uptake and removal to investigate ways that
Psychosocial Determinants of Romantic Inclination Among Indian Youth
Directory of Open Access Journals (Sweden)
D. Barani Ganth
2017-10-01
Full Text Available The present study was conducted with the aim of understanding the psychosocial determinants of romantic inclination among youth in India. We involved 779 student participants from a large central university in south India in the age range of 18-24 years. The participants filled measures on romantic inclination, personality, attachment style, interpersonal attraction, and social influence on romantic relationship in addition to a questionnaire on demographic information and relationship history. Analysis of the data revealed that males showed higher level of romantic inclination than females. Those who had current/past involvement in a romantic relationship (Lovers showed higher levels of romantic inclination than those who had never involved in a romantic relationship (Non-lovers. Parents’ type of marriage (Love/arranged, close fiends’ involvement in romantic relationship too had a discriminatory role in romantic inclination. Romantic inclination was significantly related to personality factors, attachment style, media and peer influences on romantic relationships and interpersonal attraction. Extraversion, openness to experience, agreeableness, media influence, peer influence, secure attachment and physical attraction emerged as significant predictors of romantic inclination in a regression model. Structural Equations Modeling (SEM indicated that personality, attachment style and interpersonal attraction had a significant influence on romantic inclination mediated by both media and peer influences. Romantic inclination in turn significantly predicted romantic relationship status.
Impact of flow inclination on downwind turbine loads and power
Kress, C.; Chokani, N.; Abhari, R. S.; Hashimoto, T.; Watanabe, M.; Sano, T.; Saeki, M.
2016-09-01
Wind turbines frequently operate under situations of pronounced flow inclinations, such as in complex terrain. In the present work the performance and rotor thrust of downwind and upwind turbines in upward and downward flow inclinations are experimentally investigated. In an upward flow inclination of +13°, downwind turbines are shown to have a 29% larger power output than a corresponding upwind turbine, whereas the relative increase in rotor thrust is only 9%. Furthermore, it is also shown that the performance of downwind turbines is less sensitive to changes in the flow inclination, as the upstream nacelle on downwind turbines beneficially redirects and accelerates the flow around the nacelle into the rotor plane.
The Gothic arch (needle point) tracing and condylar inclination.
el-Gheriani, A S; Winstanley, R B
1987-11-01
The records of 11 patients referred for treatment of TMJ disorders were used to compare condylar inclination found by drawing a tangent and by using a mathematic technique. Needle point tracing angles were also measured for the same patients and were compared with the condylar inclination. It can be concluded that (1) the mathematic technique outlined records a more accurate condylar angulation, and (2) there is a great variation in condylar inclination values between patients and between left and right sides of the same patient, and (3) there is no direct relationship between condylar inclination and the needle point tracing angle.
Developing a composite based elliptic spring for automotive applications
International Nuclear Information System (INIS)
Talib, Abdul Rahim Abu; Ali, Aidy; Goudah, G.; Lah, Nur Azida Che; Golestaneh, A.F.
2010-01-01
An automotive suspension system is designed to provide both safety and comfort for the vehicle occupants. In this study, finite element models were developed to optimize the material and geometry of the composite elliptical spring based on the spring rate, log life and shear stress parameters. The influence of the ellipticity ratio on the performance of woven roving-wrapped composite elliptical springs was investigated both experimentally and numerically. The study demonstrated that composite elliptical springs can be used for light and heavy trucks with substantial weight reduction. The results showed that the ellipticity ratio significantly influenced the design parameters. Composite elliptic springs with ellipticity ratios of a/b = 2 had the optimum spring parameters.
Simulation of Canopy Leaf Inclination Angle in Rice
Directory of Open Access Journals (Sweden)
Xiao-cui ZHANG
2013-11-01
Full Text Available A leaf inclination angle distribution model, which is applicable to simulate leaf inclination angle distribution in six heights of layered canopy at different growth stages, was established by component factors affecting plant type in rice. The accuracy of the simulation results was validated by measured values from a field experiment. The coefficient of determination (R2 and the root mean square error (RMSE between the simulated and measured values were 0.9472 and 3.93%, respectively. The simulation results showed that the distribution of leaf inclination angles differed among the three plant types. The leaf inclination angles were larger in the compact variety Liangyoupeijiu with erect leaves than in the loose variety Shanyou 63 with droopy leaves and the intermediate variety Liangyou Y06. The leaf inclination angles were distributed in the lower range in Shanyou 63, which matched up with field measurements. The distribution of leaf inclination angles in the same variety changed throughout the seven growth stages. The leaf inclination angles enlarged gradually from transplanting to booting. During the post-booting period, the leaf inclination angle increased in Shanyou 63 and Liangyou Y06, but changed little in Liangyoupeijiu. At every growth stage of each variety, canopy leaf inclination angle distribution on the six heights of canopy layers was variable. As canopy height increased, the layered leaf area index (LAI decreased in all the three plant types. However, while the leaf inclination angles showed little change in Liangyoupeijiu, they became larger in Shanyou 63 but smaller in Liangyou Y06. The simulation results used in the constructed model were very similar to the actual measurement values. The model provides a method for estimating canopy leaf inclination angle distribution in rice production.
A FUNDAMENTAL LINE FOR ELLIPTICAL GALAXIES
International Nuclear Information System (INIS)
Nair, Preethi; Van den Bergh, Sidney; Abraham, Roberto G.
2011-01-01
Recent studies have shown that massive galaxies in the distant universe are surprisingly compact, with typical sizes about a factor of three smaller than equally massive galaxies in the nearby universe. It has been suggested that these massive galaxies grow into systems resembling nearby galaxies through a series of minor mergers. In this model the size growth of galaxies is an inherently stochastic process, and the resulting size-luminosity relationship is expected to have considerable environmentally dependent scatter. To test whether minor mergers can explain the size growth in massive galaxies, we have closely examined the scatter in the size-luminosity relation of nearby elliptical galaxies using a large new database of accurate visual galaxy classifications. We demonstrate that this scatter is much smaller than has been previously assumed, and may even be so small as to challenge the plausibility of the merger-driven hierarchical models for the formation of massive ellipticals.
Elliptical Modons On The Beta-plane
Kizner, Z.; Khvoles, R.; Berson, D.
Conventional modons are stationary localized solutions to the equation of the quasi- geostrophic PV conservation. The contour separating the interior area, where the streamlines are closed, from the exterior area (open streamlines) is circular, the depen- dences of PV vs. streamfunction (SF) in the interior and exterior regions being linear (but different) in such modons. We consider barotropic modons on the beta-plane, in which the separating contour differs from a circle. While the exterior solution is given analytically, the interior solution is found using a variant of the Newton-Kantorovich procedure. It is shown that any deviation of the modon form from a circle causes nonlinearity of the internal PV vs. SF dependence. Special emphasis has been placed on elliptical modons. The difference of the elliptical modons on the f-plane (Boyd and Ma, 1990) from those on the beta-plane is discussed, and the 'dispersion relationships' of the beta-plane modons are analyzed.
A holomorphic anomaly in the elliptic genus
International Nuclear Information System (INIS)
Murthy, Sameer
2014-01-01
We consider a class of gauged linear sigma models (GLSMs) in two dimensions that flow to non-compact (2,2) superconformal field theories in the infra-red, a prototype of which is the SL(2,ℝ)/U(1) (cigar) coset. We compute the elliptic genus of the GLSMs as a path-integral on the torus using supersymmetric localization. We find that the result is a Jacobi-like form that is non-holomorphic in the modular parameter τ of the torus, with mock modular behavior. This agrees with a previously-computed expression in the cigar coset. We show that the lack of holomorphicity of the elliptic genus arises from the contributions of a compact boson carrying momentum and winding excitations. This boson has an axionic shift symmetry and plays the role of a compensator field that is needed to cancel the chiral anomaly in the rest of the theory.
Performance of an elliptically tapered neutron guide
International Nuclear Information System (INIS)
Muehlbauer, Sebastian; Stadlbauer, Martin; Boeni, Peter; Schanzer, Christan; Stahn, Jochen; Filges, Uwe
2006-01-01
Supermirror coated neutron guides are used at all modern neutron sources for transporting neutrons over large distances. In order to reduce the transmission losses due to multiple internal reflection of neutrons, ballistic neutron guides with linear tapering have been proposed and realized. However, these systems suffer from an inhomogeneous illumination of the sample. Moreover, the flux decreases significantly with increasing distance from the exit of the neutron guide. We propose using elliptically tapered guides that provide a more homogeneous phase space at the sample position as well as a focusing at the sample. Moreover, the design of the guide system is simplified because ellipses are simply defined by their long and short axes. In order to prove the concept we have manufactured a doubly focusing guide and investigated its properties with neutrons. The experiments show that the predicted gains using the program package McStas are realized. We discuss several applications of elliptic guides in various fields of neutron physics
Elliptic differential equations theory and numerical treatment
Hackbusch, Wolfgang
2017-01-01
This book simultaneously presents the theory and the numerical treatment of elliptic boundary value problems, since an understanding of the theory is necessary for the numerical analysis of the discretisation. It first discusses the Laplace equation and its finite difference discretisation before addressing the general linear differential equation of second order. The variational formulation together with the necessary background from functional analysis provides the basis for the Galerkin and finite-element methods, which are explored in detail. A more advanced chapter leads the reader to the theory of regularity. Individual chapters are devoted to singularly perturbed as well as to elliptic eigenvalue problems. The book also presents the Stokes problem and its discretisation as an example of a saddle-point problem taking into account its relevance to applications in fluid dynamics.
Directory of Open Access Journals (Sweden)
Scott Stephens
2013-10-01
Full Text Available Current and planned wildfire detection systems are impressive but lack both sensitivity and rapid response times. A small telescope with modern detectors and significant computing capacity in geosynchronous orbit can detect small (12 m2 fires on the surface of the earth, cover most of the western United States (under conditions of moderately clear skies every few minutes or so, and attain very good signal-to-noise ratio against Poisson fluctuations in a second. Hence, these favorable statistical significances have initiated a study of how such a satellite could operate and reject the large number of expected systematic false alarms from a number of sources. Here we present both studies of the backgrounds in Geostationary Operational Environmental Satellites (GOES 15 data and studies that probe the sensitivity of a fire detection satellite in geosynchronous orbit. We suggest a number of algorithms that can help reduce false alarms, and show efficacy on a few. Early detection and response would be of true value in the United States and other nations, as wildland fires continue to severely stress resource managers, policy makers, and the public, particularly in the western US. Here, we propose the framework for a geosynchronous satellite with modern imaging detectors, software, and algorithms able to detect heat from early and small fires, and yield minute-scale detection times.
Integrable mappings via rational elliptic surfaces
International Nuclear Information System (INIS)
Tsuda, Teruhisa
2004-01-01
We present a geometric description of the QRT map (which is an integrable mapping introduced by Quispel, Roberts and Thompson) in terms of the addition formula of a rational elliptic surface. By this formulation, we classify all the cases when the QRT map is periodic; and show that its period is 2, 3, 4, 5 or 6. A generalization of the QRT map which acts birationally on a pencil of K3 surfaces, or Calabi-Yau manifolds, is also presented
Generalized Harnack Inequality for Nonhomogeneous Elliptic Equations
Julin, Vesa
2015-05-01
This paper is concerned with nonlinear elliptic equations in nondivergence form where F has a drift term which is not Lipschitz continuous. Under this condition the equations are nonhomogeneous and nonnegative solutions do not satisfy the classical Harnack inequality. This paper presents a new generalization of the Harnack inequality for such equations. As a corollary we obtain the optimal Harnack type of inequality for p( x)-harmonic functions which quantifies the strong minimum principle.
MIB Galerkin method for elliptic interface problems.
Xia, Kelin; Zhan, Meng; Wei, Guo-Wei
2014-12-15
Material interfaces are omnipresent in the real-world structures and devices. Mathematical modeling of material interfaces often leads to elliptic partial differential equations (PDEs) with discontinuous coefficients and singular sources, which are commonly called elliptic interface problems. The development of high-order numerical schemes for elliptic interface problems has become a well defined field in applied and computational mathematics and attracted much attention in the past decades. Despite of significant advances, challenges remain in the construction of high-order schemes for nonsmooth interfaces, i.e., interfaces with geometric singularities, such as tips, cusps and sharp edges. The challenge of geometric singularities is amplified when they are associated with low solution regularities, e.g., tip-geometry effects in many fields. The present work introduces a matched interface and boundary (MIB) Galerkin method for solving two-dimensional (2D) elliptic PDEs with complex interfaces, geometric singularities and low solution regularities. The Cartesian grid based triangular elements are employed to avoid the time consuming mesh generation procedure. Consequently, the interface cuts through elements. To ensure the continuity of classic basis functions across the interface, two sets of overlapping elements, called MIB elements, are defined near the interface. As a result, differentiation can be computed near the interface as if there is no interface. Interpolation functions are constructed on MIB element spaces to smoothly extend function values across the interface. A set of lowest order interface jump conditions is enforced on the interface, which in turn, determines the interpolation functions. The performance of the proposed MIB Galerkin finite element method is validated by numerical experiments with a wide range of interface geometries, geometric singularities, low regularity solutions and grid resolutions. Extensive numerical studies confirm the
A Jacobian elliptic single-field inflation
International Nuclear Information System (INIS)
Villanueva, J.R.; Gallo, Emanuel
2015-01-01
In the scenario of single-field inflation, this field is described in terms of Jacobian elliptic functions. This approach provides, when constrained to particular cases, analytic solutions already known in the past, generalizing them to a bigger family of analytical solutions. The emergent cosmology is analyzed using the Hamilton-Jacobi approach and then the main results are contrasted with the recent measurements obtained from the Planck 2015 data. (orig.)
A Jacobian elliptic single-field inflation
Energy Technology Data Exchange (ETDEWEB)
Villanueva, J.R. [Universidad de Valparaiso, Instituto de Fisica y Astronomia, Valparaiso (Chile); Centro de Astrofisica de Valparaiso, Valparaiso (Chile); Gallo, Emanuel [FaMAF, Universidad Nacional de Cordoba, Cordoba (Argentina); Instituto de Fisica Enrique Gaviola (IFEG), CONICET, Cordoba (Argentina)
2015-06-15
In the scenario of single-field inflation, this field is described in terms of Jacobian elliptic functions. This approach provides, when constrained to particular cases, analytic solutions already known in the past, generalizing them to a bigger family of analytical solutions. The emergent cosmology is analyzed using the Hamilton-Jacobi approach and then the main results are contrasted with the recent measurements obtained from the Planck 2015 data. (orig.)
Verified Indifferentiable Hashing into Elliptic Curves
Barthe, Gilles; Grégoire, Benjamin; Heraud, Sylvain; Olmedo, Federico; Zanella-Béguelin, Santiago
2012-01-01
International audience; Many cryptographic systems based on elliptic curves are proven secure in the Random Oracle Model, assuming there exist probabilistic functions that map elements in some domain (e.g. bitstrings) onto uniformly and independently distributed points in a curve. When implementing such systems, and in order for the proof to carry over to the implementation, those mappings must be instantiated with concrete constructions whose behavior does not deviate significantly from rand...
On a fourth order superlinear elliptic problem
Directory of Open Access Journals (Sweden)
M. Ramos
2001-01-01
Full Text Available We prove the existence of a nonzero solution for the fourth order elliptic equation $$Delta^2u= mu u +a(xg(u$$ with boundary conditions $u=Delta u=0$. Here, $mu$ is a real parameter, $g$ is superlinear both at zero and infinity and $a(x$ changes sign in $Omega$. The proof uses a variational argument based on the argument by Bahri-Lions cite{BL}.
Winding light beams along elliptical helical trajectories
Wen, Yuanhui; Chen, Yujie; Zhang, Yanfeng; Chen, Hui; Yu, Siyuan
2016-01-01
Conventional caustic methods in real or Fourier space produced accelerating optical beams only with convex trajectories. We develop a superposition caustic method capable of winding light beams along non-convex trajectories. We ascertain this method by constructing a one-dimensional (1D) accelerating beam moving along a sinusoidal trajectory, and subsequently extending to two-dimensional (2D) accelerating beams along arbitrarily elliptical helical trajectories. We experimentally implement the...
Chaotic Rotation of a Towed Elliptical Cylinder
Weymouth, G D
2013-01-01
In this paper I consider the self-excited rotation of an elliptical cylinder towed in a viscous fluid as a canonical model of nonlinear fluid structure interactions with possible applications in the design of sensors and energy extraction devices. First, the self-excited ellipse system is shown to be analogous to the forced bistable oscillators studied in classic chaos theory. A single variable, the distance between the pivot and the centroid, governs the system bifurcation into bi-stability....
Comparing and contrasting dispersionless injections at geosynchronous orbit during a substorm event
Kronberg, Elena; Grigorenko, Elena; Turner, Drew; Daly, Patrick; Khotyaintsev, Yuri; Kozak, Liudmyla
2017-04-01
Particle injections in the magnetosphere transport electrons and ions from the magnetotail to the radiation belts. We consider generation mechanisms of ``dispersionless'' injections, namely those with simultaneous increase of the particle flux over a wide energy range. We take advantage of multi-satellite observations which simultaneously monitor Earth's magnetospheric dynamics from the tail towards the radiation belts during a substorm event. Dispersionless injections are associated with instabilities in the plasma sheet during the growth phase of the substorm, with a dipolarization front at the onset and with magnetic flux pileup during the expansion phase. They show different spatial spread and propagation characteristics. At geosynchronous orbit (6.6 RE), the electron distributions do not have a classic power law fit but instead a bump-on-tail centered on 120 keV during dispersionless electron injections. However, electron distributions of injections associated with magnetic flux pileup in the magnetotail (13 RE) do not show such a signature. We surmise that an additional resonant acceleration occurs in-between these locations. We relate the acceleration mechanism to the electron drift resonance with ultralow frequency (ULF) waves localized in the inner magnetosphere. This study is supported by the Volkswagen Foundation.
Directory of Open Access Journals (Sweden)
Yicheng Jiang
2013-01-01
Full Text Available Bistatical SAR with geosynchronous illuminator and unmanned aerial vehicle receiver (GEO-UAV BiSAR has significant potential advantages in the field of continuous local observation under a dangerous environment within nearly 24 h. Due to the extreme platform velocity differences, the ellipse orbital movement of GEOSAR makes this BiSAR configuration not like the conventional spaceborne BiSAR. In this paper, based on the orbital kinetic characteristic of GEOSAR, we theoretically analyze the variations of bistatic configuration effect on common azimuth coverage and coherent accumulated time. In addition, two-dimension the resolution is deduced by geometrical configuration on the basis of gradient method. The simulations show that the appropriate selection of initial bistatic configuration can restrain from the appearance of the dead zone in common coverage. And the image results are obtained by frequency domain RD based on Method of Series Reversion (MSR. It is shown that GEO-UAV BiSAR has the high resolution ability.
International Nuclear Information System (INIS)
Zuo, Pingbing; Feng, Xueshang; Wang, Yi; Xie, Yanqiong; Xu, Xiaojun
2015-01-01
In this investigation, we first present a statistical result of the interplanetary sources of very strong solar wind dynamic pressure pulses (DPPs) detected by WIND during solar cycle 23. It is found that the vast majority of strong DPPs reside within solar wind disturbances. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears to be no systematic investigations on the response of GMFs to negative DPPs. Here, we study both the decompression effects of very strong negative DPPs and the compression from strong positive DPPs on GMFs at different magnetic local time sectors. In response to the decompression of strong negative DPPs, GMFs on the dayside near dawn and near dusk on the nightside, are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of the events when GOES is located at the midnight sector, the GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that under certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Here, we find that a stronger pressure enhancement may have a higher probability of producing the exceptional depression of GMF at the midnight region. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, which are stronger at the noon sector
International Nuclear Information System (INIS)
Korth, A.; Kremser, G.; Daly, P.W.; Amata, E.
1982-01-01
On August 28, 1978, the dayside magnetopause crossed the geosynchronous satellite GEOS 2 several times during a geomagnetically disturbed period, and clear signatures of the interconnection of field lines through the magnetopause were observed. The MPAE particle spectrometer provided high time resolution observations of the distribution of energetic electrons (E>22 keV) and ions (E>27 keV). Magnetometer data were used to determine the location of GEOS 2 relative to the magnetopause. The pitch angle distributions of ions and electrons were found to be strongly asymmetric with respect to 90 0 , and the asymmetries have been interpreted in terms of field-aligned particle streaming. Evidence is provided for the first time for electron streaming inside the magnetopause which continues for many bounce periods. It is concluded that magnetospheric field lines opened, at least for brief time intervals, as a consequence of interconnection with magnetosheath field lines. Comparisons of electron spectra provide evidence that the streaming electrons observed in the magnetosheath originate in the magnetosphere
Estimating the spin axis orientation of the Echostar-2 box-wing geosynchronous satellite
Earl, Michael A.; Somers, Philip W.; Kabin, Konstantin; Bédard, Donald; Wade, Gregg A.
2018-04-01
For the first time, the spin axis orientation of an inactive box-wing geosynchronous satellite has been estimated from ground-based optical photometric observations of Echostar-2's specular reflections. Recent photometric light curves obtained of Echostar-2 over four years suggest that unusually bright and brief specular reflections were occurring twice within an observed spin period. These bright and brief specular reflections suggested two satellite surfaces with surface normals separated by approximately 180°. The geometry between the satellite, the Sun, and the observing location at the time of each of the brightest observed reflections, was used to estimate Echostar-2's equatorial spin axis orientation coordinates. When considering prograde and retrograde rotation, Echostar-2's spin axis orientation was estimated to have been located within 30° of either equatorial coordinate pole. Echostar-2's spin axis was observed to have moved approximately 180° in right ascension, within a time span of six months, suggesting a roughly one year spin axis precession period about the satellite's angular momentum vector.
Entrepreneurial inclinations of women from rural areas
Directory of Open Access Journals (Sweden)
Marković-Savić Olivera S.
2014-01-01
Full Text Available Entrepreneurial inclinations of women from rural areas are shaped by the lack of business ideas and economic capital, which, in addition to financial resources, includes cultural capital in the form of knowledge and skills. The paper presents a part of a broader study on the social position of women from the rural areas of northern Kosovo and Metohija, conducted in 2013. The research was predominantly focused on entrepreneurial inclinations of rural women, and the findings suggest that private enterprise in the studied population is undeveloped as a result of two dominant reasons. The first reason is the situation which is unfavorable in terms of politics and security, and therefore, not conducive to investment security, together with the specificity in the form of complex administrative business conditions requiring compliance to parallel and mutually incompatible standards (of the Republic of Serbia and of the UNMIK administration. The second important reason for the lack of entrepreneurial initiatives is the lack of ownership of property and the means of production, since banks do not give loans without guarantees in the form of ownership of the mortgage, while other forms of financial incentives are unavailable. The respondents attended programs for acquiring new knowledge and skills only in a small number of cases, while showing the greatest susceptibility to education in traditional skills, such as training in agriculture and handicrafts, which are not the skills in line with the needs of the labor market. As the most important reasons that -prevent them from having their own business, the respondents -mentioned: the lack of ideas and the lack of financial resources. In this regard, they would find incentives in the form of grants most helpful to start their own business. The absence of funds and gender inequality form the basis for the lack of ownership of property and means of production. In addition to the shortage of financial
Abundance ratios in dwarf elliptical galaxies
Şen, Ş.; Peletier, R. F.; Boselli, A.; den Brok, M.; Falcón-Barroso, J.; Hensler, G.; Janz, J.; Laurikainen, E.; Lisker, T.; Mentz, J. J.; Paudel, S.; Salo, H.; Sybilska, A.; Toloba, E.; van de Ven, G.; Vazdekis, A.; Yesilyaprak, C.
2018-04-01
We determine abundance ratios of 37 dwarf ellipticals (dEs) in the nearby Virgo cluster. This sample is representative of the early-type population of galaxies in the absolute magnitude range -19.0 index-index diagrams and scaling relations and use the stellar population models to interpret them. We present ages, metallicities, and abundance ratios obtained from these dEs within an aperture size of Re/8. We calculate [Na/Fe] from NaD, [Ca/Fe] from Ca4227, and [Mg/Fe] from Mgb. We find that [Na/Fe] is underabundant with respect to solar, whereas [Mg/Fe] is around solar. This is exactly opposite to what is found for giant ellipticals, but follows the trend with metallicity found previously for the Fornax dwarf NGC 1396. We discuss possible formation scenarios that can result in such elemental abundance patterns, and we speculate that dEs have disc-like star formation history (SFH) favouring them to originate from late-type dwarfs or small spirals. Na-yields appear to be very metal-dependent, in agreement with studies of giant ellipticals, probably due to the large dependence on the neutron-excess in stars. We conclude that dEs have undergone a considerable amount of chemical evolution, they are therefore not uniformly old, but have extended SFH, similar to many of the Local Group galaxies.
The elliptic model for communication fluxes
International Nuclear Information System (INIS)
Herrera-Yagüe, C; Schneider, C M; González, M C; Smoreda, Z; Couronné, T; Zufiria, P J
2014-01-01
In this paper, a model (called the elliptic model) is proposed to estimate the number of social ties between two locations using population data in a similar manner to how transportation research deals with trips. To overcome the asymmetry of transportation models, the new model considers that the number of relationships between two locations is inversely proportional to the population in the ellipse whose foci are in these two locations. The elliptic model is evaluated by considering the anonymous communications patterns of 25 million users from three different countries, where a location has been assigned to each user based on their most used phone tower or billing zip code. With this information, spatial social networks are built at three levels of resolution: tower, city and region for each of the three countries. The elliptic model achieves a similar performance when predicting communication fluxes as transportation models do when predicting trips. This shows that human relationships are influenced at least as much by geography as is human mobility. (paper)
Self-filtering extremely inclined x-ray crystal monochromator
Czech Academy of Sciences Publication Activity Database
Hrdá, Jaromíra; Hrdý, Jaromír
2011-01-01
Roč. 44, č. 6 (2011), 1169-1172 ISSN 0021-8898 R&D Projects: GA MPO FR-TI1/412 Institutional research plan: CEZ:AV0Z10100522 Keywords : synchrotron radiation monochromator * x-ray crystal monochromator * inclined monochromator * inclined diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 5.152, year: 2011
Shallow bias in Mediterranean paleomagnetic directions caused by inclination error
Krijgsman, W.; Tauxe, Lisa
2004-01-01
A variety of paleomagnetic data from the Mediterranean region show a strong bias toward shallow inclinations. This pattern of shallow inclinations has been interpreted to be the result of (1) major northward terrane displacement, (2) large nondipole components in the Earth’s magnetic field, and
Analysis of deformation due to inclined load in generalized ...
African Journals Online (AJOL)
The present investigation deals with study of deformation in homogeneous, isotropic thermodiffusion elastic half-space as a result of inclined load. The inclined load is assumed to be a linear combination of normal load and tangential load. The integral transform technique is used to solve the problem. As an application of ...
46 CFR 58.01-40 - Machinery, angles of inclination.
2010-10-01
... 46 Shipping 2 2010-10-01 2010-10-01 false Machinery, angles of inclination. 58.01-40 Section 58.01-40 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS General Requirements § 58.01-40 Machinery, angles of inclination. (a) Propulsion machinery and all auxiliary...
A jig for measuring incisor inclination.
Shah, N; Spary, D J; Rock, W P
2005-06-01
The aim of this study was to design and construct a jig for measuring the inclination of the upper incisors to the maxillary plane and of the lower incisors to the mandibular plane. After several prototypes had been tested, the required properties for a successful jig were identified and a simple inexpensive device was produced. Measurements obtained when using the jig on 51 subjects were compared with cephalometric values by means of regression analysis. This revealed that measurements obtained using the jig against the upper and then the lower incisor crowns could be converted to cephalometric incisor angulations with 96 per cent accuracy to 10 degrees, by adding 23 and 3 degrees, respectively. The jig was accurate to 5 degrees on 69 per cent of occasions for the upper teeth. The 5 degrees accuracy with the lower incisors was only 27 per cent, although over a 6 degree range it improved to 78 per cent. For upper and lower tooth measurements combined, the jig was accurate to within 6 degrees on 75 per cent of occasions.
Elliptical Galaxies: Rotationally Distorted, After All
Directory of Open Access Journals (Sweden)
Caimmi, R.
2009-12-01
Full Text Available On the basis of earlier investigations onhomeoidally striated Mac Laurin spheroids and Jacobi ellipsoids (Caimmi and Marmo2005, Caimmi 2006a, 2007, different sequences of configurations are defined and represented in the ellipticity-rotation plane, $({sf O}hat{e}chi_v^2$. The rotation parameter, $chi_v^2$, is defined as the ratio, $E_mathrm{rot}/E_mathrm{res}$, of kinetic energy related to the mean tangential equatorial velocity component, $M(overline{v_phi}^2/2$, to kineticenergy related to tangential equatorial component velocity dispersion, $Msigma_{phiphi}^2/2$, andresidual motions, $M(sigma_{ww}^2+sigma_{33}^2/2$.Without loss of generality (above a thresholdin ellipticity values, the analysis is restricted to systems with isotropic stress tensor, whichmay be considered as adjoint configurationsto any assigned homeoidally striated density profile with anisotropic stress tensor, different angular momentum, and equal remaining parameters.The description of configurations in the$({sf O}hat{e}chi_v^2$ plane is extendedin two respects, namely (a from equilibriumto nonequilibrium figures, where the virialequations hold with additional kinetic energy,and (b from real to imaginary rotation, wherethe effect is elongating instead of flattening,with respect to the rotation axis.An application is made toa subsample $(N=16$ of elliptical galaxies extracted from richer samples $(N=25,~N=48$of early type galaxies investigated within theSAURON project (Cappellari et al. 2006, 2007.Sample objects are idealized as homeoidallystriated MacLaurinspheroids and Jacobi ellipsoids, and theirposition in the $({sf O}hat{e}chi_v^2$plane is inferred from observations followinga procedure outlined in an earlier paper(Caimmi 2009b. The position of related adjoint configurations with isotropic stresstensor is also determined. With a singleexception (NGC 3379, slow rotators arecharacterized by low ellipticities $(0lehat{e}<0.2$, low anisotropy parameters$(0ledelta<0
Energy Technology Data Exchange (ETDEWEB)
Djidel, S.; Bouamar, M.; Khedrouche, D., E-mail: dkhedrouche@yahoo.com [LASS (Laboratoired’Analyse des Signaux et Systèmes), Department of Electronics, University of M’sila BP.166, Route Ichebilia, M’sila, 28000 Algeria (Algeria)
2016-04-21
This paper presents a performances study of UWB monopole antenna using half-elliptic radiator conformed on elliptical surface. The proposed antenna, simulated using microwave studio computer CST and High frequency simulator structure HFSS, is designed to operate in frequency interval over 3.1 to 40 GHz. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. The proposed antenna structure is suitable for ultra-wideband applications, which is, required for many wearable electronics applications.
International Nuclear Information System (INIS)
Djidel, S.; Bouamar, M.; Khedrouche, D.
2016-01-01
This paper presents a performances study of UWB monopole antenna using half-elliptic radiator conformed on elliptical surface. The proposed antenna, simulated using microwave studio computer CST and High frequency simulator structure HFSS, is designed to operate in frequency interval over 3.1 to 40 GHz. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. The proposed antenna structure is suitable for ultra-wideband applications, which is, required for many wearable electronics applications.
Inclined asymmetric librations in exterior resonances
Voyatzis, G.; Tsiganis, K.; Antoniadou, K. I.
2018-04-01
Librational motion in Celestial Mechanics is generally associated with the existence of stable resonant configurations and signified by the existence of stable periodic solutions and oscillation of critical (resonant) angles. When such an oscillation takes place around a value different than 0 or π , the libration is called asymmetric. In the context of the planar circular restricted three-body problem, asymmetric librations have been identified for the exterior mean motion resonances (MMRs) 1:2, 1:3, etc., as well as for co-orbital motion (1:1). In exterior MMRs the massless body is the outer one. In this paper, we study asymmetric librations in the three-dimensional space. We employ the computational approach of Markellos (Mon Not R Astron Soc 184:273-281, https://doi.org/10.1093/mnras/184.2.273, 1978) and compute families of asymmetric periodic orbits and their stability. Stable asymmetric periodic orbits are surrounded in phase space by domains of initial conditions which correspond to stable evolution and librating resonant angles. Our computations were focused on the spatial circular restricted three-body model of the Sun-Neptune-TNO system (TNO = trans-Neptunian object). We compare our results with numerical integrations of observed TNOs, which reveal that some of them perform 1:2 resonant, inclined asymmetric librations. For the stable 1:2 TNO librators, we find that their libration seems to be related to the vertically stable planar asymmetric orbits of our model, rather than the three-dimensional ones found in the present study.
Development of locomotion over inclined surfaces in laying hens.
LeBlanc, C; Tobalske, B; Bowley, S; Harlander-Matauschek, A
2018-03-01
The purpose of the present study was to evaluate locomotor strategies during development in domestic chickens (Gallus gallus domesticus); we were motivated, in part, by current efforts to improve the design of housing systems for laying hens which aim to reduce injury and over-exertion. Using four strains of laying hens (Lohmann Brown, Lohmann LSL lite, Dekalb White and Hyline Brown) throughout this longitudinal study, we investigated their locomotor style and climbing capacity in relation to the degree (0 to 70°) of incline, age (2 to 36 weeks) and the surface substrate (sandpaper or wire grid). Chicks and adult fowl performed only walking behavior to climb inclines ⩽40° and performed a combination of wing-assisted incline running (WAIR) or aerial ascent on steeper inclines. Fewer birds used their wings to aid their hind limbs when climbing 50° inclines on wire grid surface compared with sandpaper. The steepness of angle achieved during WAIR and the tendency to fly instead of using WAIR increased with increasing age and experience. White-feathered strains performed more wing-associated locomotor behavior compared with brown-feathered strains. A subset of birds was never able to climb incline angles >40° even when using WAIR. Therefore, we suggest that inclines of up to 40° should be provided for hens in three-dimensional housing systems, which are easily negotiated (without wing use) by chicks and adult fowl.
Natural Circulation Characteristics of a Symmetric Loop under Inclined Conditions
Directory of Open Access Journals (Sweden)
Xingtuan Yang
2014-01-01
Full Text Available Natural circulation is an important process for primary loops of some marine integrated reactors. The reactor works under inclined conditions when severe accidents happen to the ship. In this paper, to investigate the characteristics of natural circulation, experiments were conducted in a symmetric loop under the inclined angle of 0~45°. A CFD model was also set up to predict the behaviors of the loop beyond the experimental scope. Total circulation flow rate decreases with the increase of inclined angle. Meanwhile one circulation is depressed while the other is enhanced, and accordingly the disparity between the branch circulations arises and increases with the increase of inclined angle. Circulation only takes place in one branch circuit at large inclined angle. Also based on the CFD model, the influences of flow resistance distribution and loop configuration on natural circulation are predicted. The numerical results show that to design the loop with the configuration of big altitude difference and small width, it is favorable to reduce the influence of inclination; however too small loop width will cause severe reduction of circulation ability at large angle inclination.
Sound Attenuation in Elliptic Mufflers Using a Regular Perturbation Method
Banerjee, Subhabrata; Jacobi, Anthony M.
2012-01-01
The study of sound attenuation in an elliptical chamber involves the solution of the Helmholtz equation in elliptic coordinate systems. The Eigen solutions for such problems involve the Mathieu and the modified Mathieu functions. The computation of such functions poses considerable challenge. An alternative method to solve such problems had been proposed in this paper. The elliptical cross-section of the muffler has been treated as a perturbed circle, enabling the use of a regular perturbatio...
On Fibonacci Numbers Which Are Elliptic Korselt Numbers
2014-11-17
On Fibonacci numbers which are elliptic Korselt numbers Florian Luca School of Mathematics University of the Witwatersrand P. O. Box Wits 2050, South...is a CM elliptic curve with CM field Q( √ −d), then the set of n for which the nth Fibonacci number Fn satisfies an elliptic Korselt criterion for Q...Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that
Galofaro, Joel T.; Vayner, Boris V.; Hillard, Grover B.
2011-01-01
The present ground based investigations give the first definitive look describing the expected on-orbit charging behavior of Orion UltraFlex array coupons in the Low Earth Orbital and Geosynchronous Environments. Furthermore, it is important to note that the LEO charging environment also applies to the International Space Station as well as to the lunar mission charging environments. The GEO charging environment includes the bounding case for all lunar orbital and lunar surface mission environments. The UltraFlex thin film photovoltaic array technology has been targeted to become the sole power system for life support and on-orbit power for the manned Aires Crew Exploration Vehicle. It is therefore, crucial to gain an understanding of the complex charging behavior to answer some of the basic performance and survivability issues in an attempt to ascertain that a single UltraFlex array design will be able to cope with the projected worst case LEO and GEO charging environments. Testing was limited to four array coupons, two coupons each from two different array manufactures, Emcore and Spectrolab. The layout of each array design is identical and varies only in the actual cell technology used. The individual array cells from each manufacturer have an antireflection layered coating and come in two different varieties either uncoated (only AR coating) or coated with a thin conducting ITO layer. The LEO Plasma tests revealed that all four coupons passed the arc threshold -120 V bias tests. GEO electron gun charging tests revealed that only front side area of ITO coated coupons passed tests. Only the Emcore AR array passed backside Stage 2 GEO Tests.
Koblick, D. C.; Shankar, P.; Xu, S.
Previously, there have been many commercial proposals and extensive academic studies regarding ground and space based sensors to assist a space surveillance network in obtaining metric observations of satellites and debris near Geosynchronous Earth Orbit (GEO). Most use physics based models for geometric constraints, lighting, and tasker/scheduler operations of sensor architectures. Under similar physics modeling assumptions, the space object catalog is often different due to proprietary standards and datasets. Lack of catalog commonality between studies creates barriers and difficulty comparing performance benefits of sensor trades. To solve this problem, we have constructed a future GEO space catalog from publicly available datasets and literature. The annual number of new payloads and rocket bodies is drawn from a Poisson distribution while the growth of the current GEO catalog is bootstrapped from the historical payload, upper stage, and debris data. We adopt a spherically symmetric explosion model and couple it with the NASA standard breakup model to simulate explosions of payloads and rocket bodies as they are the primary drivers of the debris population growth. The cumulative number of fragments follow a power-law distribution. Result from 1,000 random catalog growth simulations indicates that the GEO space object population in the year 2050 will include over 3,600 objects, nearly half of which are debris greater than 10 cm spherical diameter. The number of rocket bodies and dead payloads is projected to nearly double over the next 33 years. For comparison, the current Air Force Space Command catalog snapshot contains fewer than 50 pieces of debris and coarse Radar Cross Section (RCS) estimates which include: small, medium, and large. The current catalog may be sufficient for conjunction studies, but not for analyzing future sensor system performance. The 2050 GEO projected catalog will be available online for commercial/academic research and development.
Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime
Anderson, Paul V.
The geosynchronous orbit (GEO) is a unique commodity of the satellite industry that is becoming increasingly contaminated with orbital debris, but is heavily populated with high-value assets from the civil, commercial, and defense sectors. The GEO arena is home to hundreds of communications, data transmission, and intelligence satellites collectively insured for an estimated 18.3 billion USD. As the lack of natural cleansing mechanisms at the GEO altitude renders the lifetimes of GEO debris essentially infinite, conjunction and risk assessment must be performed to safeguard operational assets from debris collisions. In this thesis, longitude-dependent debris congestion is characterized by predicting the number of near-miss events per day for every longitude slot at GEO, using custom debris propagation tools and a torus intersection metric. Near-miss events with the present-day debris population are assigned risk levels based on GEO-relative position and speed, and this risk information is used to prioritize the population for debris removal target selection. Long-term projections of debris growth under nominal launch traffic, mitigation practices, and fragmentation events are also discussed, and latitudinal synchronization of the GEO debris population is explained via node variations arising from luni-solar gravity. In addition to characterizing localized debris congestion in the GEO ring, this thesis further investigates the conjunction risk to operational satellites or debris removal systems applying low-thrust propulsion to raise orbit altitude at end-of-life to a super-synchronous disposal orbit. Conjunction risks as a function of thrust level, miss distance, longitude, and semi-major axis are evaluated, and a guidance method for evading conjuncting debris with continuous thrust by means of a thrust heading change via single-shooting is developed.
A Note on Arithmetic Progressions on Elliptic Curves
Campbell, Garikai
2003-02-01
Andrew Bremner (Experiment. Math. 8 (1999), 409-413) has described a technique for producing infinite families of elliptic curves containing length 7 and length 8 arithmetic progressions. This note describes another way to produce infinite families of elliptic curves containing length 7 and length 8 arithmetic progressions. We illustrate how the technique articulated here gives an easy way to produce an elliptic curve containing a length 12 progression and an infinite family of elliptic curves containing a length 9 progression, with the caveat that these curves are not in Weierstrass form.
Elliptic genus derivation of 4d holomorphic blocks
Poggi, Matteo
2018-03-01
We study elliptic vortices on ℂ × T 2 by considering the 2d quiver gauge theory describing their moduli spaces. The elliptic genus of these moduli spaces is the elliptic version of vortex partition function of the 4d theory. We focus on two examples: the first is a N = 1, U( N ) gauge theory with fundamental and anti-fundamental matter; the second is a N = 2, U( N ) gauge theory with matter in the fundamental representation. The results are instances of 4d "holomorphic blocks" into which partition functions on more complicated surfaces factorize. They can also be interpreted as free-field representations of elliptic Virasoro algebrae.
Elliptic multiple zeta values and one-loop superstring amplitudes
Energy Technology Data Exchange (ETDEWEB)
Broedel, Johannes [Institut für Theoretische Physik, Eidgenössische Technische Hochschule Zürich,Wolfgang-Pauli-Strasse 27, 8093 Zürich (Switzerland); Mafra, Carlos R. [Department of Applied Mathematics and Theoretical Physics, University of Cambridge,Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Matthes, Nils [Fachbereich Mathematik, Universität Hamburg,Bundesstraße 55, 20146 Hamburg (Germany); Schlotterer, Oliver [Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut,Am Mühlenberg 1, 14476 Potsdam (Germany)
2015-07-21
We investigate iterated integrals on an elliptic curve, which are a natural genus-one generalization of multiple polylogarithms. These iterated integrals coincide with the multiple elliptic polylogarithms introduced by Brown and Levin when constrained to the real line. At unit argument they reduce to an elliptic analogue of multiple zeta values, whose network of relations we start to explore. A simple and natural application of this framework are one-loop scattering amplitudes in open superstring theory. In particular, elliptic multiple zeta values are a suitable language to express their low energy limit. Similar to the techniques available at tree-level, our formalism allows to completely automatize the calculation.
COLORS OF ELLIPTICALS FROM GALEX TO SPITZER
International Nuclear Information System (INIS)
Schombert, James M.
2016-01-01
Multi-color photometry is presented for a large sample of local ellipticals selected by morphology and isolation. The sample uses data from the Galaxy Evolution Explorer ( GALEX ), Sloan Digital Sky Survey (SDSS), Two Micron All-Sky Survey (2MASS), and Spitzer to cover the filters NUV , ugri , JHK and 3.6 μ m. Various two-color diagrams, using the half-light aperture defined in the 2MASS J filter, are very coherent from color to color, meaning that galaxies defined to be red in one color are always red in other colors. Comparison to globular cluster colors demonstrates that ellipticals are not composed of a single age, single metallicity (e.g., [Fe/H]) stellar population, but require a multi-metallicity model using a chemical enrichment scenario. Such a model is sufficient to explain two-color diagrams and the color–magnitude relations for all colors using only metallicity as a variable on a solely 12 Gyr stellar population with no evidence of stars younger than 10 Gyr. The [Fe/H] values that match galaxy colors range from −0.5 to +0.4, much higher (and older) than population characteristics deduced from Lick/IDS line-strength system studies, indicating an inconsistency between galaxy colors and line indices values for reasons unknown. The NUV colors have unusual behavior, signaling the rise and fall of the UV upturn with elliptical luminosity. Models with blue horizontal branch tracks can reproduce this behavior, indicating the UV upturn is strictly a metallicity effect.
Constraints on stellar populations in elliptical galaxies
International Nuclear Information System (INIS)
Rose, J.A.
1985-01-01
Photographic image-tube spectra in the wavelength interval 3400--4500 A have been obtained for 12 elliptical galaxy nuclei and for a number of Galactic globular and open clusters in integrated light. The spectra have a wavelength resolution of 2.5 A and a high signal-to-noise ratio. A new quantitative three-dimensional spectral-classification system that has been calibrated on a sample of approx.200 individual stars (Rose 1984) is used to analyze the integrated spectra of the ellipical galaxy nuclei and to compare them with those of the globular clusters. This system is based on spectral indices that are formed by comparing neighborhood spectral features and is unaffected by reddening. The following results have been found: (1) Hot stars (i.e., spectral types A and B) contribute only 2% to the integrated spectra of elliptical galaxies at approx.4000 A, except in the nucleus of NGC 205, where the hot component dominates. This finding is based on a spectral index formed from the relative central intensities in the Ca II H+Hepsilon and Ca II K lines, which is shown to be constant for late-type (i.e., F, G, and K) stars, but changes drastically at earlier types. The observed Ca II H+Hepsilon/Ca II K indices in ellipticals can be reproduced by the inclusion of a small metal-poor population (as in the globular cluster M5) that contributes approx.8% of the light at 4000 A. Such a contribution is qualitatively consistent with the amount of
COLORS OF ELLIPTICALS FROM GALEX TO SPITZER
Energy Technology Data Exchange (ETDEWEB)
Schombert, James M., E-mail: jschombe@uoregon.edu [Department of Physics, University of Oregon, Eugene, OR 97403 (United States)
2016-12-01
Multi-color photometry is presented for a large sample of local ellipticals selected by morphology and isolation. The sample uses data from the Galaxy Evolution Explorer ( GALEX ), Sloan Digital Sky Survey (SDSS), Two Micron All-Sky Survey (2MASS), and Spitzer to cover the filters NUV , ugri , JHK and 3.6 μ m. Various two-color diagrams, using the half-light aperture defined in the 2MASS J filter, are very coherent from color to color, meaning that galaxies defined to be red in one color are always red in other colors. Comparison to globular cluster colors demonstrates that ellipticals are not composed of a single age, single metallicity (e.g., [Fe/H]) stellar population, but require a multi-metallicity model using a chemical enrichment scenario. Such a model is sufficient to explain two-color diagrams and the color–magnitude relations for all colors using only metallicity as a variable on a solely 12 Gyr stellar population with no evidence of stars younger than 10 Gyr. The [Fe/H] values that match galaxy colors range from −0.5 to +0.4, much higher (and older) than population characteristics deduced from Lick/IDS line-strength system studies, indicating an inconsistency between galaxy colors and line indices values for reasons unknown. The NUV colors have unusual behavior, signaling the rise and fall of the UV upturn with elliptical luminosity. Models with blue horizontal branch tracks can reproduce this behavior, indicating the UV upturn is strictly a metallicity effect.
Dwarf elliptical galaxies with kinematically decoupled cores
De Rijcke, S.; Dejonghe, H.; Zeilinger, W. W.; Hau, G. K. T.
2004-10-01
We present, for the first time, photometric and kinematical evidence, obtained with FORS2 on the VLT, for the existence of kinematically decoupled cores (KDCs) in two dwarf elliptical galaxies; FS76 in the NGC 5044 group and FS373 in the NGC 3258 group. Both kinematically peculiar subcomponents rotate in the same sense as the main body of their host galaxy but betray their presence by a pronounced bump in the rotation velocity profiles at a radius of about 1''. The KDC in FS76 rotates at 10 ± 3 km s-1, with the host galaxy rotating at 15 ± 6 km s-1; the KDC in FS373 has a rotation velocity of 6 ± 2 km s-1 while the galaxy itself rotates at 20 ± 5 km s-1. FS373 has a very complex rotation velocity profile with the velocity changing sign at 1.5 Re. The velocity and velocity dispersion profiles of FS76 are asymmetric at larger radii. This could be caused by a past gravitational interaction with the giant elliptical NGC 5044, which is at a projected distance of 50 kpc. We argue that these decoupled cores are most likely not produced by mergers in a group or cluster environment because of the prohibitively large relative velocities. A plausible alternative is offered by flyby interactions between a dwarf elliptical or its disky progenitor and a massive galaxy. The tidal forces during an interaction at the relative velocities and impact parameters typical for a group environment exert a torque on the dwarf galaxy that, according to analytical estimates, transfers enough angular momentum to its stellar envelope to explain the observed peculiar kinematics.
Guided modes of elliptical metamaterial waveguides
International Nuclear Information System (INIS)
Halterman, Klaus; Feng, Simin; Overfelt, P. L.
2007-01-01
The propagation of guided electromagnetic waves in open elliptical metamaterial waveguide structures is investigated. The waveguide contains a negative-index media core, where the permittivity ε and permeability μ are negative over a given bandwidth. The allowed mode spectrum for these structures is numerically calculated by solving a dispersion relation that is expressed in terms of Mathieu functions. By probing certain regions of parameter space, we find the possibility exists to have extremely localized waves that transmit along the surface of the waveguide
Neutral hydrogen in elliptical and IO galaxies
International Nuclear Information System (INIS)
Bottinelli, L.; Gouguenheim, L.
1979-01-01
New HI detections have been obtained using the Nancay radiotelescope for NGC 2974 and 3962. These results and the large scale distribution obtained for NGC 3962 indicate that the HI-rich elliptical galaxies exhibit common properties which are not easily explained by accretion of an intergalactic cloud. The field aroud NGC 1052 has been mapped and there is an HI connection with the neighbouring galaxies. The HI content of several IO galaxies indicates that the galaxies which are members of groups are relatively HI-rich; this could be produced by additional HI coming from companion galaxies [fr
Ellipticity dependence of the near-threshold harmonics of H2 in an elliptical strong laser field.
Yang, Hua; Liu, Peng; Li, Ruxin; Xu, Zhizhan
2013-11-18
We study the ellipticity dependence of the near-threshold (NT) harmonics of pre-aligned H2 molecules using the time-dependent density functional theory. The anomalous maximum appearing at a non-zero ellipticity for the generated NT harmonics can be attributed to multiphoton effects of the orthogonally polarized component of the elliptical driving laser field. Our calculation also shows that the structure of the bound-state, such as molecular alignment and bond length, can be sensitively reflected on the ellipticity dependence of the near-threshold harmonics.
Aqua/Aura Spring 2017 Inclination Adjust Maneuver Series
Noyes, Thomas; Stezelberger, Shane
2017-01-01
This will be presented at the International Earth Science Constellation Mission Operations Working Group meeting June 13-15, 2017 to discuss the AquaAura Spring 2017 Inclination Adjust Maneuver series.
Brilliance and flux reduction in imperfect inclined crystals
International Nuclear Information System (INIS)
Lee, W.K.; Blasdell, R.C.; Fernandez, P.B.; Macrander, A.T.; Mills, D.M.
1996-01-01
The inclined crystal geometry has been suggested as a method of reducing the surface absorbed power density of high-heat-load monochromators for third-generation synchrotron radiation sources. Computer simulations have shown that if the crystals are perfectly aligned and have no strains then the diffraction properties of a pair of inclined crystals are very similar to a pair of conventional flat crystals with only subtle effects differentiating the two configurations. However, if the crystals are strained, these subtle differences in the behavior of inclined crystals can result in large beam divergences causing brilliance and flux losses. This manuscript elaborates on these issues and estimates potential brilliance and flux losses from strained inclined crystals at the APS
Systems of pillarless working of adjacent, sloped and inclined seams
Energy Technology Data Exchange (ETDEWEB)
Batmanov, Yu.K.; Bakhtin, A.F.; Bulavka, E.I.
1979-01-01
An analysis is made (advantages and disadvantages) of existing and recommended (pillarless) systems of working adjacent, sloped, and inclined seams. The economic benefits, area and extent of those systems are indicated. 8 references, 4 figures.
Anisotropic elliptic PDEs for feature classification.
Wang, Shengfa; Hou, Tingbo; Li, Shuai; Su, Zhixun; Qin, Hong
2013-10-01
The extraction and classification of multitype (point, curve, patch) features on manifolds are extremely challenging, due to the lack of rigorous definition for diverse feature forms. This paper seeks a novel solution of multitype features in a mathematically rigorous way and proposes an efficient method for feature classification on manifolds. We tackle this challenge by exploring a quasi-harmonic field (QHF) generated by elliptic PDEs, which is the stable state of heat diffusion governed by anisotropic diffusion tensor. Diffusion tensor locally encodes shape geometry and controls velocity and direction of the diffusion process. The global QHF weaves points into smooth regions separated by ridges and has superior performance in combating noise/holes. Our method's originality is highlighted by the integration of locally defined diffusion tensor and globally defined elliptic PDEs in an anisotropic manner. At the computational front, the heat diffusion PDE becomes a linear system with Dirichlet condition at heat sources (called seeds). Our new algorithms afford automatic seed selection, enhanced by a fast update procedure in a high-dimensional space. By employing diffusion probability, our method can handle both manufactured parts and organic objects. Various experiments demonstrate the flexibility and high performance of our method.
Can mergers make slowly rotating elliptical galaxies
International Nuclear Information System (INIS)
White, S.D.M.
1979-01-01
The results of numerical experiments are used to guide an analytic discussion of hyperbolic mergers among an uncorrelated galaxy population. The expected merger rate is derived as a function of progenitor mass and relative angular momentum, and is used to predict the distribution of the parameter V/sub c//sigma 0 for merger products where V/sub c/ is the maximum observed rotation velocity in a galaxy and sigma 0 is its central velocity dispersion. The median value of this parameter for mergers between comparable galaxies is estimated to be 0.65 and is higher than the observed value in any of the 14 galaxies for which data are available. It seems unlikely that most elliptical galaxies are the result of single or multiple mergers between initially unbound stellar systems; further observational and theoretical work is suggested which should lead to a conclusive test of this picture. The present arguments cannot, however, exclude formation from low angular momentum elliptical orbits
Matrix models, geometric engineering and elliptic genera
International Nuclear Information System (INIS)
Hollowood, Timothy; Iqbal, Amer; Vafa, Cumrun
2008-01-01
We compute the prepotential of N = 2 supersymmetric gauge theories in four dimensions obtained by toroidal compactifications of gauge theories from 6 dimensions, as a function of Kaehler and complex moduli of T 2 . We use three different methods to obtain this: matrix models, geometric engineering and instanton calculus. Matrix model approach involves summing up planar diagrams of an associated gauge theory on T 2 . Geometric engineering involves considering F-theory on elliptic threefolds, and using topological vertex to sum up worldsheet instantons. Instanton calculus involves computation of elliptic genera of instanton moduli spaces on R 4 . We study the compactifications of N = 2* theory in detail and establish equivalence of all these three approaches in this case. As a byproduct we geometrically engineer theories with massive adjoint fields. As one application, we show that the moduli space of mass deformed M5-branes wrapped on T 2 combines the Kaehler and complex moduli of T 2 and the mass parameter into the period matrix of a genus 2 curve
Psychosocial Determinants of Romantic Inclination Among Indian Youth
D. Barani Ganth; S. Kadhiravan
2017-01-01
The present study was conducted with the aim of understanding the psychosocial determinants of romantic inclination among youth in India. We involved 779 student participants from a large central university in south India in the age range of 18-24 years. The participants filled measures on romantic inclination, personality, attachment style, interpersonal attraction, and social influence on romantic relationship in addition to a questionnaire on demographic information and relationship histor...
Levan, P.
2010-09-01
Geosynchronous objects appear as unresolved blurs even when observed with the largest ground-based telescopes. Due to the lack of any spatial detail, two or more objects appearing at similar brightness levels within the spectral bandpass they are observed are difficult to distinguish. Observing a changing pattern of such objects from one time epoch to another showcases the deficiencies in associating individual objects before and after the configuration change. This paper explores solutions to this deficiency in the form of spectral (under small business innovative research) and phase curve analyses. The extension of the technique to phase curves proves to be a powerful new capability.
Uplift Capacity of Inclined Underreamed Piles Subjected to Vertical Load
Rahman, Md. Akilur; Sengupta, Siddhartha
2017-12-01
Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Inclined (batter) piles are used to support such structures, and to carry the horizontal and vertical loads resulted from the overturning moments. Though studies have been done with inclined piles having no underream bulb, little information is available in the literature about estimating the uplift capacity of inclined underreamed piles. In the present study laboratory experiments have been done with vertically loaded model piles having no underream as well as with one and two underreams. The piles were positioned at angle of inclination of θ = 0°, 10°, 20°, 30° (with vertical); and placed in locally available sand under vertical uplift load. Three different pile stem diameters (D = 20, 25, and 35 mm) were used. The corresponding pile length to stem diameter (l/D) ratio were 18, 14, and 10 respectively. Experiments had been conducted with two relative different densities (45 and 70%) of sand. The failure uplift loads were obtained in each case. It had been found that for inclined piles increase in number of underream bulbs from 0 to 2 was quite effective in resisting uplift loads corresponding to piles having l/D equals to 10. The percentage decreases in uplift capacity corresponding to increase in inclination angle were more pronounced for piles with double underreams.
Trunk muscle activity with different sitting postures and pelvic inclination.
Watanabe, Masahiro; Kaneoka, Koji; Wada, Yusuke; Matsui, Yasushi; Miyakawa, Shumpei
2014-01-01
Sitting posture may often place large burden on trunk muscles, while trunk muscle activities in the sitting posture have not been well clarified. In this study, a difference in trunk muscle activity between two kinds of sitting postures was evaluated, focusing on low back pain induced by posture holding. An experiment was conducted on the subjects sitting on a stable-seat and on an unstable-seat, with the pelvis inclined forward, backward, rightward, and leftward. With the pelvis inclined forward, rightward and leftward, muscle activities were significantly increased in a stable-seat sitting posture. In contrast, no significant increase in muscle activity was observed with the pelvis inclined in every direction in an unstable-seat sitting posture. With the pelvis inclined in the stable-seat sitting posture, muscle activities were imbalanced, while with the pelvis inclined in the unstable-seat sitting posture, muscle activities were not imbalanced. Thus, it is suggested that with the pelvis inclined to the maximum extent in the stable-seat sitting posture, low back pain may be induced by imbalanced muscle activities.
Inclination evolution of protoplanetary discs around eccentric binaries
Zanazzi, J. J.; Lai, Dong
2018-01-01
It is usually thought that viscous torque works to align a circumbinary disc with the binary's orbital plane. However, recent numerical simulations suggest that the disc may evolve to a configuration perpendicular to the binary orbit ('polar alignment) if the binary is eccentric and the initial disc-binary inclination is sufficiently large. We carry out a theoretical study on the long-term evolution of inclined discs around eccentric binaries, calculating the disc warp profile and dissipative torque acting on the disc. For discs with aspect ratio H/r larger than the viscosity parameter α, bending wave propagation effectively makes the disc precess as a quasi-rigid body, while viscosity acts on the disc warp and twist to drive secular evolution of the disc-binary inclination. We derive a simple analytic criterion (in terms of the binary eccentricity and initial disc orientation) for the disc to evolve towards polar alignment with the eccentric binary. When the disc has a non-negligible angular momentum compared to the binary, the final 'polar alignment' inclination angle is reduced from 90°. For typical protoplanetary disc parameters, the time-scale of the inclination evolution is shorter than the disc lifetime, suggesting that highly inclined discs and planets may exist orbiting eccentric binaries.
Thermo-economic performance of inclined solar water distillation systems
Directory of Open Access Journals (Sweden)
Agboola Phillips O.
2015-01-01
Full Text Available This study investigates the thermo-economic performance of different configurations of inclined solar water desalination for parameters such as daily production, efficiency, system cost and distilled water production cost. The four different configurations considered for this study are as follows; 1. Inclined solar water distillation with bare absorber plate (IISWD with daily production of 5.46 kg/m2 day and daily efficiency of 48.3%. 2. Inclined solar water distillation with wick on absorber plate (IISWDW with daily production of 6.41kg/m2 day and daily efficiency 50.3%. 3. Inclined solar water distillation with wire mesh on absorber plate (IISWDWM with daily production n of 3.03 kg/m2 day and daily efficiency 32.6%. 4. Inclined solar water distillation with bare absorber plate (ISWD. (Control System with daily production of 3.25 kg/m2 day and daily efficiency of 40.1%. The systems potable water cost price ranges from 0.03 $/L for IISWDW to 0.06$/L for IISWDWM System. All the systems are economically and technically feasible as a solar distillation system for potable water in Northern Cyprus. The price of potable water from water vendors/hawkers ranges from 0.11-0.16 $/L. It is more economically viable to have the rooftop inclined solar water desalination system than procuring potable water from vendors.`
TRANSIT TIMING VARIATIONS FOR INCLINED AND RETROGRADE EXOPLANETARY SYSTEMS
International Nuclear Information System (INIS)
Payne, Matthew J.; Ford, Eric B.; Veras, Dimitri
2010-01-01
We perform numerical calculations of the expected transit timing variations (TTVs) induced on a hot-Jupiter by an Earth-mass perturber. Motivated by the recent discoveries of retrograde transiting planets, we concentrate on an investigation of the effect of varying relative planetary inclinations, up to and including completely retrograde systems. We find that planets in low-order (e.g., 2:1) mean-motion resonances (MMRs) retain approximately constant TTV amplitudes for 0 deg. 170 deg. Systems in higher order MMRs (e.g., 5:1) increase in TTV amplitude as inclinations increase toward 45 deg., becoming approximately constant for 45 deg. 135 deg. Planets away from resonance slowly decrease in TTV amplitude as inclinations increase from 0 deg. to 180 deg., whereas planets adjacent to resonances can exhibit a huge range of variability in TTV amplitude as a function of both eccentricity and inclination. For highly retrograde systems (135 deg. < i ≤ 180 deg.), TTV signals will be undetectable across almost the entirety of parameter space, with the exceptions occurring when the perturber has high eccentricity or is very close to an MMR. This high inclination decrease in TTV amplitude (on and away from resonance) is important for the analysis of the known retrograde and multi-planet transiting systems, as inclination effects need to be considered if TTVs are to be used to exclude the presence of any putative planetary companions: absence of evidence is not evidence of absence.
Picone-type inequalities for nonlinear elliptic equations and their applications
Directory of Open Access Journals (Sweden)
Takaŝi Kusano
2001-01-01
Full Text Available Picone-type inequalities are derived for nonlinear elliptic equations, and Sturmian comparison theorems are established as applications. Oscillation theorems for forced super-linear elliptic equations and superlinear-sublinear elliptic equations are also obtained.
Newton flows for elliptic functions: A pilot study
Twilt, F.; Helminck, G.F.; Snuverink, M.; van den Brug, L.
2008-01-01
Elliptic Newton flows are generated by a continuous, desingularized Newton method for doubly periodic meromorphic functions on the complex plane. In the special case, where the functions underlying these elliptic Newton flows are of second-order, we introduce various, closely related, concepts of
three solutions for a semilinear elliptic boundary value problem
Indian Academy of Sciences (India)
69
Keywords: The Laplacian operator, elliptic problem, Nehari man- ifold, three critical points, weak solution. 1. Introduction. Let Ω be a smooth bounded domain in RN , N ≥ 3 . In this work, we show the existence of at least three solutions for the semilinear elliptic boundary- value problem: (Pλ).. −∆u = f(x)|u(x)|p−2u(x) + ...
Explosive solutions of elliptic equations with absorption and non ...
Indian Academy of Sciences (India)
Home; Journals; Proceedings – Mathematical Sciences; Volume 112; Issue 3. Explosive Solutions of Elliptic Equations with Absorption and Non-Linear Gradient Term. Marius Ghergu Constantin Niculescu Vicenţiu Rădulescu ... Keywords. Explosive solution; semilinear elliptic problem; entire solution; maximum principle.
Stability estimates for hp spectral element methods for elliptic ...
Indian Academy of Sciences (India)
Home; Journals; Proceedings – Mathematical Sciences; Volume 112; Issue 4. Stability Estimates for ℎ- Spectral Element Methods for Elliptic Problems. Pravir Dutt ... In a series of papers of which this is the first we study how to solve elliptic problems on polygonal domains using spectral methods on parallel computers.
Two-dimensional steady unsaturated flow through embedded elliptical layers
Bakker, Mark; Nieber, John L.
2004-12-01
New analytic element solutions are presented for unsaturated, two-dimensional steady flow in vertical planes that include nonoverlapping impermeable elliptical layers and elliptical inhomogeneities. The hydraulic conductivity, which is represented by an exponential function of the pressure head, differs between the inside and outside of an elliptical inhomogeneity; both the saturated hydraulic conductivity and water retention parameters are allowed to differ between the inside and outside. The Richards equation is transformed, through the Kirchhoff transformation and a second standard transformation, into the modified Helmholtz equation. Analytic element solutions are obtained through separation of variables in elliptical coordinates. The resulting equations for the Kirchhoff potential consist of infinite sums of products of exponentials and modified Mathieu functions. In practical applications the series are truncated but still fulfill the differential equation exactly; boundary conditions are met approximately but up to machine accuracy, provided that enough terms are used. The pressure head, saturation, and flow may be computed analytically at any point in the vadose zone. Examples are given of the shadowing effect of an impermeable elliptical layer in a uniform flow field and funnel-type flow between two elliptical inhomogeneities. The presented solutions may be applied to study transport processes in vadose zones containing many impermeable elliptical layers or elliptical inhomogeneities.
Selmer groups of elliptic curves that can be arbitrarily large
Schaefer, EF; Kloosterman, Remke
In this article, it is shown that certain kinds of Selmer groups of elliptic curves can be arbitrarily large. The main result is that if p is a prime at least 5, then p-Selmer groups of elliptic curves can be arbitrarily large if one ranges over number fields of degree at most g + 1 over the
Elliptic Riesz operators on the weighted special atom spaces
Directory of Open Access Journals (Sweden)
Kuang Jichang
1996-01-01
Full Text Available In this paper we study the boundedness and convergence of σrs(f and σ˜rs(f, the elliptic Riesz operators and the conjugate elliptic Riesz operators of order s>0, on the weighted special atom space B(ω.
Galois representations of elliptic curves and abelian entanglements
Brau Avila, Julio
2015-01-01
This thesis deals primarily with the study of Galois representations attached to torsion points on elliptic curves. In the first chapter we consider the problem of determining the image of the Galois representation flE attached to a non-CM elliptic curve over the rational number field Q. We give a
An efficient modified Elliptic Curve Digital Signature Algorithm | Kiros ...
African Journals Online (AJOL)
Many digital signatures which are based on Elliptic Curves Cryptography (ECC) have been proposed. Among these digital signatures, the Elliptic Curve Digital Signature Algorithm (ECDSA) is the widely standardized one. However, the verification process of ECDSA is slower than the signature generation process. Hence ...
Near-infrared photometry of bright elliptical galaxies
Peletier, R. F.; Valentijn, E. A.; Jameson, R. F.
High-quality visual-infrared color profiles have been determined for elliptical galaxies for the first time. Surface photometry in J and K is presented for 12 bright elliptical galaxies, and the results have been combined with CCD data in visual passbands. It is shown that the galaxies become bluer
Anyons and the elliptic Calogero-Sutherland model
Langmann, Edwin
2000-01-01
We obtain a second quantization of the elliptic Calogero-Sutherland (eCS) model by constructing a quantum field theory model of anyons on a circle and at a finite temperature. This yields a remarkable identity involving anyon correlation functions and providing an algorithm for solving of the eCS model. The eigenfunctions obtained define an elliptic generalization of the Jack polynomials.
On the elliptic flow for nearly symmetric collisions and nuclear ...
Indian Academy of Sciences (India)
In figure 1, the final-state elliptic flow is displayed for the free particles (upper panel), light mass fragments (LMFs) (2 ≤ A ≤ 4) (middle panel) and intermediate mass fragments. Figure 1. The elliptic flow as a function of the transverse momentum at incident energy. 95 MeV/nucleon for free particles, LMFs and IMFs in top, ...
New Explicit Conditions of Elliptic Curve Traces for FR-Reduction
MIYAJI, Atsuko; NAKABAYASHI, Masaki; TAKANO, Shunzou
2001-01-01
Elliptic curve cryptosystems are based on the elliptic curve discrete logarithm problem (ECDLP). If elliptic curve cryptosystems avoid FR-reduction and anomalous elliptic curve over F_q, then with current knowledge we can construct elliptic curve cryptosystems over a smaller definition field. ECDLP has an interesting property that the security deeply depends on elliptic curve traces rather than definition fields, which does not occur in the case of the discrete logarithm problem (DLP). Theref...
Dynamic susceptibility of onion in ferromagnetic elliptical nanoring
Mu, Congpu; Song, Jiefang; Xu, Jianghong; Wen, Fusheng
2016-06-01
Micromagnetic simulation was performed to investigate the equilibrium state and dynamic susceptibility spectra of magnetic elliptical nanoring. There are two equilibrium states (onion and vortex) obtained in elliptical nanoring. The onion state can be used to record information in MRAM. And it is important to investigate the dynamic susceptibility spectra of onion state, which is closely related to writing and reading speed of magnetic memory devices. Those results show that two or three resonance peaks are found under different thickness of elliptical nanoring with onion state, respectively. The low resonance frequency of two resonance peaks is increasing with the arm width of the elliptical ring, but is decreasing with the thickness. However, the high frequency of two resonance peaks is decreasing with the arm width of the elliptical ring.
Dynamic susceptibility of onion in ferromagnetic elliptical nanoring
Directory of Open Access Journals (Sweden)
Congpu Mu
2016-06-01
Full Text Available Micromagnetic simulation was performed to investigate the equilibrium state and dynamic susceptibility spectra of magnetic elliptical nanoring. There are two equilibrium states (onion and vortex obtained in elliptical nanoring. The onion state can be used to record information in MRAM. And it is important to investigate the dynamic susceptibility spectra of onion state, which is closely related to writing and reading speed of magnetic memory devices. Those results show that two or three resonance peaks are found under different thickness of elliptical nanoring with onion state, respectively. The low resonance frequency of two resonance peaks is increasing with the arm width of the elliptical ring, but is decreasing with the thickness. However, the high frequency of two resonance peaks is decreasing with the arm width of the elliptical ring.
Ellipticity of near-threshold harmonics from stretched molecules.
Li, Weiyan; Dong, Fulong; Yu, Shujuan; Wang, Shang; Yang, Shiping; Chen, Yanjun
2015-11-30
We study the ellipticity of near-threshold harmonics (NTH) from aligned molecules with large internuclear distances numerically and analytically. The calculated harmonic spectra show a broad plateau for NTH which is several orders of magnitude higher than that for high-order harmonics. In particular, the NTH plateau shows high ellipticity at small and intermediate orientation angles. Our analyses reveal that the main contributions to the NTH plateau come from the transition of the electron from continuum states to these two lowest bound states of the system, which are strongly coupled together by the laser field. Besides continuum states, higher excited states also play a role in the NTH plateau, resulting in a large phase difference between parallel and perpendicular harmonics and accordingly high ellipticity of the NTH plateau. The NTH plateau with high intensity and large ellipticity provides a promising manner for generating strong elliptically-polarized extreme-ultraviolet (EUV) pulses.
Barbee, Brent William; Carpenter, J. Russell; Heatwole, Scott; Markley, F. Landis; Moreau, Michael; Naasz, Bo J.; VanEepoel, John
2010-01-01
The feasibility and benefits of various spacecraft servicing concepts are currently being assessed, and all require that the servicer spacecraft perform rendezvous, proximity, and capture operations with the target spacecraft to be serviced. Many high-value spacecraft, which would be logical targets for servicing from an economic point of view, are located in geosynchronous orbit, a regime in which autonomous rendezvous and capture operations are not commonplace. Furthermore, existing GEO spacecraft were not designed to be serviced. Most do not have cooperative relative navigation sensors or docking features, and some servicing applications, such as de-orbiting of a non-functional spacecraft, entail rendezvous and capture with a spacecraft that may be non-functional or un-controlled. Several of these challenges have been explored via the design of a notional mission in which a nonfunctional satellite in geosynchronous orbit is captured by a servicer spacecraft and boosted into super-synchronous orbit for safe disposal. A strategy for autonomous rendezvous, proximity operations, and capture is developed, and the Orbit Determination Toolbox (ODTBX) is used to perform a relative navigation simulation to assess the feasibility of performing the rendezvous using a combination of angles-only and range measurements. Additionally, a method for designing efficient orbital rendezvous sequences for multiple target spacecraft is utilized to examine the capabilities of a servicer spacecraft to service multiple targets during the course of a single mission.
Evaluation of performance of veterinary in-clinic hematology analyzers.
Rishniw, Mark; Pion, Paul D
2016-12-01
A previous study provided information regarding the quality of in-clinic veterinary biochemistry testing. However, no similar studies for in-clinic veterinary hematology testing have been conducted. The objective of this study was to assess the quality of hematology testing in veterinary in-clinic laboratories using results obtained from testing 3 levels of canine EDTA blood samples. Clinicians prepared blood samples to achieve measurand concentrations within, below, and above their RIs and evaluated the samples in triplicate using their in-clinic analyzers. Quality was assessed by comparison of calculated total error with quality requirements, determination of sigma metrics, use of a quality goal index, and agreement between in-clinic and reference laboratory instruments. Suitability for statistical quality control was determined using adaptations from the computerized program, EZRules3. Evaluation of 10 veterinary in-clinic hematology analyzers showed that these instruments often fail to meet quality requirements. At least 60% of analyzers reasonably determined RBC, WBC, HCT, and HGB, when assessed by most quality goal criteria; platelets were less reliably measured, with 80% deemed suitable for low platelet counts, but only 30% for high platelet counts, and automated differential leukocyte counts were generally considered unsuitable for clinical use with fewer than 40% of analyzers meeting the least stringent quality goal requirements. Fewer than 50% of analyzers were able to meet requirements for statistical quality control for any measurand. These findings reflect the current status of in-clinic hematology analyzer performance and provide a basis for future evaluations of the quality of veterinary laboratory testing. © 2016 American Society for Veterinary Clinical Pathology.
Structural equation modeling for alteration of occlusal plane inclination.
Shigeta, Yuko; Ogawa, Takumi; Nakamura, Yoshiharu; Ando, Eriko; Hirabayashi, Rio; Ikawa, Tomoko
2015-07-01
Occlusal plane inclination is important to maintain a normal opening closing/biting function. However, there can be several causes that lead to alterations of the occlusal plane. The purpose of this study was to observe variations of occlusal plane inclination in adult patients, and to uncover the factors affecting changes in occlusal plane inclination with aging. Subjects were 143 patients. A cephalometric image was taken of these patients. In this study, our inquiry points were age, 3 variables on intra-oral findings, and 7 variables on cephalometric analysis. To evaluate the possible causes that affect occlusal plane inclination, factor analysis was carried out, and each component was treated as factors, which were then statistically applied to a structural equation model. Statistical analysis was carried out through the SPSS 20.0 (SPSS Inc., Chicago, USA). In all patients, Camper-occlusal plane angle (COA) ranged from -25.7 to -4.9° (Mean±SD: -6.4±5.36). In the 60 patients who had no missing teeth, COA ranged from -11.6 to -4.9° (Mean±SD: -3.3±3.31). From the results of the structural analysis, it was suggested that the occlusal plane changes to counter-clockwise (on the right lateral cephalograms) with aging. In this study, variations of occlusal plane inclination in adult patients were observed, and the factors affecting changes in occlusal plane inclination with aging were investigated via factor analysis. From our results, it was suggested that the mandibular morphology change and loss of teeth with aging influence occlusal plane inclination. Copyright © 2015 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.
Parametric bases for elliptic boundary value problem
Gusev, A. A.; Vinitsky, S. I.; Chuluunbaatar, O.; Derbov, V. L.; Góźdź, A.; Krassovitskiy, P. M.
2018-02-01
We consider the calculation schemes in the framework of Kantorovich method that consist in the reduction of a 3D elliptic boundary-value problem (BVP) to a set of second-order ordinary differential equations (ODEs) using the parametric basis functions. These functions are solution of the 2D parametric BVP. The coefficients in the ODEs are the parametric eigenvalues and the potential matrix elements expressed by the integrals of the eigenfunctions multiplied by their first derivatives with respect to the parameter. We calculate the parametric basis functions numerically in the general case using the high-accuracy finite element method. The efficiency of the proposed calculation schemes and algorithms is demonstrated by the example of the BVP describing the bound states of helium atom.
Hardware Accelerators for Elliptic Curve Cryptography
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C. Puttmann
2008-05-01
Full Text Available In this paper we explore different hardware accelerators for cryptography based on elliptic curves. Furthermore, we present a hierarchical multiprocessor system-on-chip (MPSoC platform that can be used for fast integration and evaluation of novel hardware accelerators. In respect of two application scenarios the hardware accelerators are coupled at different hierarchy levels of the MPSoC platform. The whole system is implemented in a state of the art 65 nm standard cell technology. Moreover, an FPGA-based rapid prototyping system for fast system verification is presented. Finally, a metric to analyze the resource efficiency by means of chip area, execution time and energy consumption is introduced.
Universal geometrical scaling of the elliptic flow
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Andrés C.
2015-01-01
Full Text Available The presence of scaling variables in experimental observables provide very valuable indications of the dynamics underlying a given physical process. In the last years, the search for geometric scaling, that is the presence of a scaling variable which encodes all geometrical information of the collision as well as other external quantities as the total energy, has been very active. This is motivated, in part, for being one of the genuine predictions of the Color Glass Condensate formalism for saturation of partonic densities. Here we extend these previous findings to the case of experimental data on elliptic flow. We find an excellent scaling for all centralities and energies, from RHIC to LHC, with a simple generalization of the scaling previously found for other observables and systems. Interestingly, the case of the photons, difficult to reconcile in most formalisms, nicely fit the scaling curve. We discuss on the possible interpretations of this finding in terms of initial or final state effects.
Induced Ellipticity for Inspiraling Binary Systems
Randall, Lisa; Xianyu, Zhong-Zhi
2018-01-01
Although gravitational waves tend to erase eccentricity of an inspiraling binary system, ellipticity can be generated in the presence of surrounding matter. We present a semianalytical method for understanding the eccentricity distribution of binary black holes (BHs) in the presence of a supermassive BH in a galactic center. Given a matter distribution, we show how to determine the resultant eccentricity analytically in the presence of both tidal forces and evaporation up to one cutoff and one matter-distribution-independent function, paving the way for understanding the environment of detected inspiraling BHs. We furthermore generalize Kozai–Lidov dynamics to situations where perturbation theory breaks down for short time intervals, allowing more general angular momentum exchange, such that eccentricity is generated even when all bodies orbit in the same plane.
Elliptic flow and incomplete equilibration at RHIC
Bhalerao, R S; Borghini, N; Ollitrault, Jean Yves
2005-01-01
We argue that RHIC data, in particular those on the anisotropic flow coefficients v_2 and v_4, suggest that the matter produced in the early stages of nucleus-nucleus collisions is incompletely thermalized. We interpret the parameter (1/S)(dN/dy), where S is the transverse area of the collision zone and dN/dy the multiplicity density, as an indicator of the number of collisions per particle at the time when elliptic flow is established, and hence as a measure of the degree of equilibration. This number serves as a control parameter which can be varied experimentally by changing the system size, the centrality or the beam energy. We provide predictions for Cu-Cu collisions at RHIC as well as for Pb-Pb collisions at the LHC.
Winding light beams along elliptical helical trajectories
Wen, Yuanhui; Chen, Yujie; Zhang, Yanfeng; Chen, Hui; Yu, Siyuan
2016-07-01
Conventional caustic methods in real or Fourier space produced accelerating optical beams only with convex trajectories. We developed a superposition caustic method capable of winding light beams along nonconvex trajectories. We ascertain this method by constructing a one-dimensional (1D) accelerating beam moving along a sinusoidal trajectory, and subsequently extending to two-dimensional (2D) accelerating beams along arbitrarily elliptical helical trajectories. We experimentally implemented the method with a compact and robust integrated optics approach by fabricating micro-optical structures on quartz glass plates to perform the spatial phase and amplitude modulation to the incident light, generating beam trajectories highly consistent with prediction. The theoretical and implementation methods can in principle be extended to the construction of accelerating beams with a wide variety of nonconvex trajectories, thereby opening up a route of manipulating light beams for fundamental research and practical applications.
Elliptical field-of-view PROPELLER imaging.
Devaraj, Ajit; Pipe, James G
2009-09-01
Traditionally two-dimensional scans are designed to support an isotropic field-of-view (iFOV). When imaging elongated objects, significant savings in scan time can potentially be achieved by supporting an elliptical field-of-view (eFOV). This work presents an empirical closed-form solution to adapt the PROPELLER trajectory for an eFOV. The proposed solution is built on the geometry of the PROPELLER trajectory permitting the scan prescription and data reconstruction to remain largely similar to standard PROPELLER. The achieved FOV is experimentally validated by the point spread function (PSF) of a phantom scan. The details of potential savings in scan time and the signal-to-noise ratio (SNR) performance in comparison to iFOV scans for both phantom and in-vivo images are also described.
Díaz, José Antonio; Mahajan, Virendra N
2013-08-20
Recently, Hasan and Shaker published a set of orthonormal polynomials for an annular elliptical pupil obtained by the Gram-Schmidt orthogonalization of the Zernike circle polynomials [Appl. Opt.51, 8490 (2012)]. However, the expressions for many of the polynomials are incorrect, apparently due to wrong usage of the Gram-Schmidt orthogonalization process. We provide the correct equations for the orthogonalization process and the expressions for the orthonormal polynomials obtained by applying them.
PURCELL EFFECT IN EXTREMELY ANISOTROPIC ELLIPTIC METAMATERIALS
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Alexander V. Chebykin
2014-11-01
Full Text Available The paper deals with theoretical demonstration of Purcell effect in extremely anisotropic metamaterials with elliptical isofrequency surface. This effect is free from association with divergence in density of states unlike the case of hyperbolic metamaterials. It is shown that a large Purcell factor can be observed without excitation of modes with large wave vectors in one direction, and the component of the wave vector normal to the layers is less than k0. For these materials the possibility is given for increasing of the power radiated in the medium, as well as the power radiated from material into free space across the medium border situated transversely to the layers. We have investigated isofrequency contours and the dependence of Purcell factor from the frequency for infinite layered metamaterial structure. In the visible light range strong spatial dispersion gives no possibility to obtain enhancement of spontaneous emission in metamaterial with unit cell which consists of two layers. This effect can be achieved in periodic metal-dielectric layered nanostructures with a unit cell containing two different metallic layers and two dielectric ones. Analysis of the dependences for Purcell factor from the frequency shows that the spontaneous emission is enhanced by a factor of ten or more only for dipole orientation along metamaterial layers, but in the case of the transverse orientation radiation can be enhanced only 2-3 times at most. The results can be used to create a new type of metamaterials with elliptical isofrequency contours, providing a more efficient light emission in the far field.
Dynamics of unforced and vertically forced rocking elliptical and semi-elliptical disks
Wang, Xue-She; Mazzoleni, Michael J.; Mann, Brian P.
2018-03-01
This paper presents the results of an investigation on the dynamics of unforced and vertically forced rocking elliptical and semi-elliptical disks. The full equation of motion for both rocking disks is derived from first principles. For unforced behavior, Lamb's method is used to derive the linear natural frequency of both disks, and harmonic balance is used to determine their amplitude-dependent rocking frequencies. A stability analysis then reveals that the equilibria and stability of the two disks are considerably different, as the semi-elliptical disk has a super-critical pitchfork bifurcation that enables it to exhibit bistable rocking behavior. Experimental studies were conducted to verify the trends. For vertically forced behavior, numerical investigations show the disk's responses to forward and reverse frequency sweeps. Three modes of periodicity were observed for the steady state behavior. Experiments were performed to verify the frequency responses and the presence of the three rocking modes. Comparisons between the experiments and numerical investigations show good agreement.
Instability timescale for the inclination instability in the solar system
Zderic, Alexander; Madigan, Ann-Marie; Fleisig, Jacob
2018-04-01
The gravitational influence of small bodies is often neglected in the study of solar system dynamics. However, this is not always an appropriate assumption. For example, mutual secular torques between low mass particles on eccentric orbits can result in a self-gravity instability (`inclination instability'; Madigan & McCourt 2016). During the instability, inclinations increase exponentially, eccentricities decrease (detachment), and orbits cluster in argument of perihelion. In the solar system, the orbits of the most distant objects show all three of these characteristics (high inclination: Volk & Malhotra (2017), detachment: Delsanti & Jewitt (2006), and argument of perihelion clustering: Trujillo & Sheppard (2014)). The inclination instability is a natural explanation for these phenomena.Unfortunately, full N-body simulations of the solar system are unfeasible (N ≈ O(1012)), and the behavior of the instability depends on N, prohibiting the direct application of lower N simulations. Here we present the instability timescale's functional dependence on N, allowing us to extrapolate our simulation results to that appropriate for the solar system. We show that ~5 MEarth of small icy bodies in the Sedna region is sufficient for the inclination instability to occur in the outer solar system.
Influence of occlusal plane inclination and mandibular deviation on esthetics.
Corte, Cristiane Cherobini Dalla; Silveira, Bruno Lopes da; Marquezan, Mariana
2015-10-01
The aim of this study was to assess the degree of perception of occlusal plane inclination and mandibular deviation in facial esthetics, assessed by laypeople, dentists and orthodontists. A woman with 5.88° of inclination and 5.54 mm of mandibular deviation was selected and, based on her original photograph, four new images were created correcting the deviations and creating more symmetric faces and smiles. Examiners assessed the images by means of a questionnaire. Their opinions were compared by qualitative and quantitative analyses. A total of 45 laypeople, 27 dentists and 31 orthodontists filled out the questionnaires. All groups were able to perceive the asymmetry; however, orthodontists were more sensitive, identifying asymmetries as from 4.32° of occlusal plane inclination and 4.155 mm of mandibular deviation (pocclusal plane inclination and 5.54 mm of mandibular deviation (pOcclusal plane inclination and mandibular deviation were perceived by all groups, but orthodontists presented higher perception of deviations.
Effective Elliptic Models for Efficient Wavefield Extrapolation in Anisotropic Media
Waheed, Umair bin
2014-05-01
Wavefield extrapolation operator for elliptically anisotropic media offers significant cost reduction compared to that of transversely isotropic media (TI), especially when the medium exhibits tilt in the symmetry axis (TTI). However, elliptical anisotropy does not provide accurate focusing for TI media. Therefore, we develop effective elliptically anisotropic models that correctly capture the kinematic behavior of the TTI wavefield. Specifically, we use an iterative elliptically anisotropic eikonal solver that provides the accurate traveltimes for a TI model. The resultant coefficients of the elliptical eikonal provide the effective models. These effective models allow us to use the cheaper wavefield extrapolation operator for elliptic media to obtain approximate wavefield solutions for TTI media. Despite the fact that the effective elliptic models are obtained by kinematic matching using high-frequency asymptotic, the resulting wavefield contains most of the critical wavefield components, including the frequency dependency and caustics, if present, with reasonable accuracy. The methodology developed here offers a much better cost versus accuracy tradeoff for wavefield computations in TTI media, considering the cost prohibitive nature of the problem. We demonstrate the applicability of the proposed approach on the BP TTI model.
Electromagnetic fields and Green's functions in elliptical vacuum chambers
Persichelli, S.; Biancacci, N.; Migliorati, M.; Palumbo, L.; Vaccaro, V. G.
2017-10-01
In this paper, we discuss the electromagnetic interaction between a point charge travelling inside a waveguide of elliptical cross section, and the waveguide itself. By using a convenient expansion of the Mathieu functions, useful in particular for treating a variety of problems in applied mathematics and physics with elliptic geometry, we first obtain the longitudinal electromagnetic field of a point charge (Green's function) in free space in terms of elliptical coordinates. This expression allows, then, to calculate the scattered field due to the boundary conditions in our geometry. By summing the contribution of the direct or primary field and the indirect field scattered by the boundary, after a careful choice of some expansion expressions, we derive a novel formula of the longitudinal electric field, in any transverse position of the elliptical cross section, generated by the charge moving along the longitudinal axis of the waveguide. The obtained expression is represented in a closed form, it can be differentiated and integrated, it can be used to fully describe the radiation process of a particle beam travelling inside a waveguide of elliptical cross section, and it is valid for any elliptic geometry. The equations are used to evaluate the coupling impedance due to indirect space charge in case of elliptical geometry. In addition, they are useful as preliminary studies for the determination of the coupling impedance in different cases involving elliptic vacuum chambers, as, for example, the effect of the finite conductivity of the beam pipe wall or the geometrical variation of the vacuum chamber due to elliptic step transitions existing in some accelerators.
Investigation on computation of elliptical microwave plasma cavity
Liao, Xiaoli; Liu, Hua; Zhang, Kai
2008-12-01
In recent years, the advance of the elliptical resonant cavity and focus cavity is known by many people. There are homogeneous and multipatternal virtues in the focus dimensional microwave field of the elliptical resonant cavity. It is very suitable for applying the low power microwave biological effect equipment. However, when designing the elliptical resonant cavity may meet the problems of complex and huge computation need to be solved. This paper proposed the simple way of approximate processing the Mathieu function. It can greatly simplify the difficulty and decrease the scale of computation. This method can satisfy the requirements of research and development within project permitted precision.
Dusty Feedback from Massive Black Holes in Two Elliptical Galaxies
Temi, P.; Brighenti, F.; Mathews, W. G.; Amblard, A.; Riguccini, L.
2013-01-01
Far-infrared dust emission from elliptical galaxies informs us about galaxy mergers, feedback energy outbursts from supermassive black holes and the age of galactic stars. We report on the role of AGN feedback observationally by looking for its signatures in elliptical galaxies at recent epochs in the nearby universe. We present Herschel observations of two elliptical galaxies with strong and spatially extended FIR emission from colder grains 5-10 kpc distant from the galaxy cores. Extended excess cold dust emission is interpreted as evidence of recent feedback-generated AGN energy outbursts in these galaxies, visible only in the FIR, from buoyant gaseous outflows from the galaxy cores.
On the velocity fields in elliptical galaxies with dark matter
International Nuclear Information System (INIS)
Yoshii, Yuzuru
1987-01-01
The tensor virial theorem is used to investigate a dynamical state of an oblate system of luminous matter which is embedded in the more extended dark matter with reasonable density profiles. The relation between the ratio of rotation to random velocities and the ellipticity of a luminous system has been derived. If dark matter is distributed almost spherically, then the rotation velocity in the luminous system with isotropic velocity dispersions is larger than in the isolated system with the same ellipticity. Therefore, the anisotropy in velocity dispersions necessary to be consistent with the observed slow rotations of giant ellipticals should be larger than that for the isolated system without dark matter. (author)
Elliptic genera and vertex operator super-algebras
Tamanoi, Hirotaka
1999-01-01
This monograph deals with two aspects of the theory of elliptic genus: its topological aspect involving elliptic functions, and its representation theoretic aspect involving vertex operator super-algebras. For the second aspect, elliptic genera are shown to have the structure of modules over certain vertex operator super-algebras. The vertex operators corresponding to parallel tensor fields on closed Riemannian Spin Kähler manifolds such as Riemannian tensors and Kähler forms are shown to give rise to Virasoro algebras and affine Lie algebras. This monograph is chiefly intended for topologists and it includes accounts on topics outside of topology such as vertex operator algebras.
Multilevel quadrature of elliptic PDEs with log-normal diffusion
Harbrecht, Helmut
2015-01-07
We apply multilevel quadrature methods for the moment computation of the solution of elliptic PDEs with lognormally distributed diffusion coefficients. The computation of the moments is a difficult task since they appear as high dimensional Bochner integrals over an unbounded domain. Each function evaluation corresponds to a deterministic elliptic boundary value problem which can be solved by finite elements on an appropriate level of refinement. The complexity is thus given by the number of quadrature points times the complexity for a single elliptic PDE solve. The multilevel idea is to reduce this complexity by combining quadrature methods with different accuracies with several spatial discretization levels in a sparse grid like fashion.
Droplet Depinning on Inclined Surfaces at High Reynolds Numbers
White, Edward; Singh, Natasha; Lee, Sungyon
2017-11-01
Contact angle hysteresis enables a sessile liquid drop to adhere to a solid surface when the surface is inclined, the drop is exposed to gas-phase flow, or the drop is exposed to both forcing modalities. Previous work by Schmucker and White (2012.DFD.M4.6) identified critical depinning Weber numbers for water drops subject to gravity- and wind-dominated forcing. This work extends the Schmucker and White data and finds the critical depinning Weber number obeys a two-slope linear model. Under pure wind forcing at Reynolds numbers above 1500 and with zero surface inclination, Wecrit = 8.0 . For non-zero inclinations, α, Wecrit decreases proportionally to A Bo sinα where A is the drop aspect ratio and Bo is its Bond number. The same relationship holds for α behavior. Supported by the National Science Foundation through Grant CBET-1605947.
Natural Frequencies and Mode Shapes of Statically Deformed Inclined Risers
Alfosail, Feras
2016-10-15
We investigate numerically the linear vibrations of inclined risers using the Galerkin approach. The riser is modeled as an Euler-Bernoulli beam accounting for the nonlinear mid-plane stretching and self-weight. After solving for the initial deflection of the riser due to self-weight, we use a Galerkin expansion employing 15 axially loaded beam mode shapes to solve the eigenvalue problem of the riser around the static equilibrium configuration. This yields the riser natural frequencies and corresponding exact mode shapes for various values of inclination angles and tension. The obtained results are validated against a boundary-layer analytical solution and are found to be in good agreement. This constitutes a basis to study the nonlinear forced vibrations of inclined risers.
Psychopathic Inclination Among Incarcerated Youth of Hazara Division Pakistan
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Sher Dil
2016-09-01
Full Text Available Present study aimed at evaluating the psychopathic inclination among youth and finding the gender differences in psychopathy. An indigenously developed Psychopathy scale (Urdu has been used in this study. Alpha reliability of the scale was .90. The study was conducted on 100 males (50 criminals and 50 non-criminals and 100 females (26 criminals and 74 non-criminals using a convenient sampling technique from three districts of Hazara division: Haripur, Abbottabad, and Mansehra. Results confirmed that there is significant difference in psychopathic inclination of males and females; criminals differed significantly from the non-criminals. The study also paves way for further investigation in the field in Pakistan.
Entrepreneurial Inclination Among Business Students: A Malaysian Study
Directory of Open Access Journals (Sweden)
Yet-Mee Lim
2012-10-01
Full Text Available Entrepreneurship has been the fundamental topics of discussion among the politicians, economists, and academics. Business creation is especially critical in developing countries to stimulate economic growth. The present study attempts to examine entrepreneurial inclination among students who are a potential source of entrepreneurs. The fi ndings of the present research study indicate that majority of our business students are not entrepreneurial-inclined. They do not seem to possess strong entrepreneurial characteristics and entrepreneurial skills, and they are not keen in starting a new business. The roles of higher institutes of education and the government in promoting entrepreneurship are discussed.
Fluorescence intensity dependence on the propagation plane inclination
International Nuclear Information System (INIS)
Fernandez, J.E.; Rubio, Marcelo; Sanchez, H.J.
1987-01-01
A Monte Carlo simulation of the primary and secondary X-ray fluorescent emission from an homogeneous and infinite thickness sample, irradiated under different inclination of the propagation plane, is carried out. An agreement with the predictions based on Sherman equations depending on the inclination angle α was found. The invariance of the primary fluorescence with respect to α and the decrease until evanescence of the secondary fluorescence for a α → π/2 are confirmed. A discussion about the physical basis of this dependence is carried out. Similar results are expected for tertiary fluorescence. (Author) [es
An imbedding theorem and its applications in degenerate elliptic equations
International Nuclear Information System (INIS)
Duong Minh Duc.
1988-06-01
We improve the Rellich-Kondrachov theorem and apply it to study strongly degenerate and singular elliptic equations. We obtain the maximum principle, Harnacks's inequality and global regularity for solutions of those equations. (author). 11 refs
Mergers of elliptical galaxies and the fundamental plane
Gonzalez-Garcia, AC; van Albada, TS; AvilaReese,; Firmani, C; Frenk, CS; Allen, YC
2003-01-01
N-body simulations have been carried out in order to explore the final state of elliptical galaxies after encounters and more expecifically whether the Fundamental Plane (FP hereafter) relation is affected by merging.
Vertical elliptic operator for efficient wave propagation in TTI media
Waheed, Umair bin
2015-08-19
Elliptic wave extrapolation operators require significantly less computational cost than the ones for transversely isotropic (TI) media. However, it does not provide accurate wavefield representation or imaging for the prevalent TI media. We propose a new vertical elliptically anisotropic (VEA) wave equation by decomposing the acoustic TI pseudo-differential wave equation. The decomposition results in a vertical elliptic differential equation and a scalar operator. The new VEA-like wave equation shares the same dispersion relation as that of the original acoustic TI wave equation. Therefore, the kinematic contents are correctly matched to the original equation. Moreover, the proposed decomposition yields better amplitude properties than the isotropic decomposition without increasing the computational load. Therefore, it exhibits better cost versus accuracy tradeoff compared to the isotropic or the tilted elliptic decompositions. We demonstrate with numerical examples that the proposed methodology is numerically stable for complex models and is free from shear-wave artifacts.
Topology of the elliptical billiard with the Hooke's potential
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Radnović Milena
2015-01-01
Full Text Available Using Fomenko graphs, we present a topological description of the elliptical billiard with Hooke's potential. [Projekat Ministarstva nauke Republike Srbije, br. 174020: Geometry and Topology of Manifolds and Integrable Dynamical Systems
Solvable nonlinear evolution PDEs in multidimensional space involving elliptic functions
Energy Technology Data Exchange (ETDEWEB)
Calogero, F [Dipartimento di Fisica, Universita di Roma ' La Sapienza' , 00185 Roma (Italy); Francoise, J-P [Laboratoire J-L Lions, UMR CNRS, Universite P-M Curie, Paris 6 (France); Sommacal, M [Dipartimento di Matematica e Informatica, Universita di Perugia, Perugia (Italy)
2007-07-27
A solvable nonlinear (system of) evolution PDEs in multidimensional space, involving elliptic functions, is identified, and certain of its solutions are exhibited. An isochronous version of this (system of) evolution PDEs in multidimensional space is also reported. (fast track communication)
Elliptic Curved Component Macro-Programming and Its Application
Yang, Zhibo; Hu, Junchen; Li, Kaiqiang; Zhang, Shiyu; Liu, Aiju
2017-10-01
Most conventional numerical control systems do not have the function of noncircular curve interpolation instruction. Manual programming is extremely challenging, automatic programming by computer-aided manufacturing software is highly sophisticated, and processing parameters cannot be easily modified. Therefore, macro-programs, which possess powerful parametric programming, are applied for the processing of noncircular curved components. The values of arguments were determined using transfer and loop statements (IF and WHILE), and elliptic curved macro-programs were achieved using normal and parameter equations in this study. The elliptic curved components were fitted using micro-sized segments or arcs. The numerical control machining tests verified the validity and viability of the macro-programs, and elliptic curved components were processed. The results indicated that the elliptic curved components processed using macro-programs met the design requirements.
Electromagnetic fields and Green functions in elliptical vacuum chambers
AUTHOR|(CDS)2084216; Biancacci, Nicolo; Migliorati, Mauro; Palumbo, Luigi; Vaccaro, Vittorio; CERN. Geneva. ATS Department
2017-01-01
In this paper, we discuss the electromagnetic interaction between a point charge travelling inside a waveguide of elliptical cross section, and the waveguide itself. By using a convenient expansion of the Mathieu functions, useful in particular for treating a variety of problems in applied mathematics and physics with elliptic geometry, we first obtain the longitudinal electromagnetic field of a point charge (Green function) in free space in terms of elliptical coordinates. This expression allows, then, to calculate the scattered field due to the boundary conditions in our geometry. By summing the contribution of the direct or primary field and the indirect field scattered by the boundary, after a careful choice of some expansion expressions, we derive a novel formula of the longitudinal electric field, in any transverse position of the elliptical cross section, generated by the charge moving along the longitudinal axis of the waveguide. The obtained expression is represented in a closed form, it can be diffe...
C1,1 regularity for degenerate elliptic obstacle problems
Daskalopoulos, Panagiota; Feehan, Paul M. N.
2016-03-01
The Heston stochastic volatility process is a degenerate diffusion process where the degeneracy in the diffusion coefficient is proportional to the square root of the distance to the boundary of the half-plane. The generator of this process with killing, called the elliptic Heston operator, is a second-order, degenerate-elliptic partial differential operator, where the degeneracy in the operator symbol is proportional to the distance to the boundary of the half-plane. In mathematical finance, solutions to the obstacle problem for the elliptic Heston operator correspond to value functions for perpetual American-style options on the underlying asset. With the aid of weighted Sobolev spaces and weighted Hölder spaces, we establish the optimal C 1 , 1 regularity (up to the boundary of the half-plane) for solutions to obstacle problems for the elliptic Heston operator when the obstacle functions are sufficiently smooth.
Electron energy spectrum in core-shell elliptic quantum wire
Directory of Open Access Journals (Sweden)
V.Holovatsky
2007-01-01
Full Text Available The electron energy spectrum in core-shell elliptic quantum wire and elliptic semiconductor nanotubes are investigated within the effective mass approximation. The solution of Schrodinger equation based on the Mathieu functions is obtained in elliptic coordinates. The dependencies of the electron size quantization spectrum on the size and shape of the core-shell nanowire and nanotube are calculated. It is shown that the ellipticity of a quantum wire leads to break of degeneration of quasiparticle energy spectrum. The dependences of the energy of odd and even electron states on the ratio between semiaxes are of a nonmonotonous character. The anticrosing effects are observed at the dependencies of electron energy spectrum on the transversal size of the core-shell nanowire.
Optimal Rendezvous and Docking Simulator for Elliptical Orbits, Phase I
National Aeronautics and Space Administration — It is proposed to develop and implement a simulation of spacecraft rendezvous and docking guidance, navigation, and control in elliptical orbit. The foundation of...
Reeves, R. D.; Balmain, K. G.
1981-01-01
A two dimensional model was developed to describe the charging of thin polymer films exposed to a uniform mon-energetic electron beam. The study was motivated by observed anomalous behavior of geosynchronous satellites which was attributed to electrical discharges associated with the differential charging of satellite surfaces of magnetospheric electrons. Electric fields both internal and external to the irradiated specimen were calculated at steady state in order to identify regions of high electrical stress. Particular emphasis was placed on evaluating the charging characteristics near the material's edge. The model was used to identify and quantify the effects of some of the experimental parameters notably: beam energy; beam angle of incidence; beam current density; material thickness; and material width. Simulations of the following situations were also conducted: positive or negative precharging over part of the surface; a central gap in the material; and a discontinuity in the material's thickness.
Frith, James; Barker, Ed; Cowardin, Heather; Buckalew, Brent; Anz-Meado, Phillip; Lederer, Susan
2017-01-01
The NASA Orbital Debris Program Office (ODPO) recently commissioned the Meter Class Autonomous Telescope (MCAT) on Ascension Island with the primary goal of obtaining population statistics of the geosynchronous (GEO) orbital debris environment. To help facilitate this, studies have been conducted using MCAT's known and projected capabilities to estimate the accuracy and timeliness in which it can survey the GEO environment. A simulated GEO debris population is created and sampled at various cadences and run through the Constrained Admissible Region Multi Hypotheses Filter (CAR-MHF). The orbits computed from the results are then compared to the simulated data to assess MCAT's ability to determine accurately the orbits of debris at various sample rates. Additionally, estimates of the rate at which MCAT will be able produce a complete GEO survey are presented using collected weather data and the proposed observation data collection cadence. The specific methods and results are presented here.
Elliptical acoustic particle motion in underwater waveguides.
Dall'Osto, David R; Dahl, Peter H
2013-07-01
Elliptical particle motion, often encountered in acoustic fields containing interference between a source signal and its reflections, can be quantified by the degree of circularity, a vector quantity formulated from acoustic particle velocity, or vector intensity measurements. Acoustic analysis based on the degree of circularity is expected to find application in ocean waveguides as its spatial dependence relates to the acquisition geometry, water column sound speed, surface conditions, and bottom properties. Vector sensor measurements from a laboratory experiment are presented to demonstrate the depth dependence of both the degree of circularity and an approximate formulation based on vertical intensity measurements. The approximation is applied to vertical intensity field measurements made in a 2006 experiment off the New Jersey coast (in waters 80 m deep) to demonstrate the effect of sediment structure on the range dependence of the degree of circularity. The mathematical formulation presented here establishes the framework to readily compute the degree of circularity from experimental measurements; the experimental examples are provided as evidence of the spatial and frequency dependence of this fundamental vector property.
Handbook of elliptic and hyperelliptic curve cryptography
Cohen, Henri; Avanzi, Roberto; Doche, Christophe; Lange, Tanja; Nguyen, Kim; Vercauteren, Frederik
2005-01-01
… very comprehensive coverage of this vast subject area … a useful and essential treatise for anyone involved in elliptic curve algorithms … this book offers the opportunity to grasp the ECC technology with a diversified and comprehensive perspective. … This book will remain on my shelf for a long time and will land on my desk on many occasions, if only because the coverage of the issues common to factoring and discrete log cryptosystems is excellent.-IACR Book Reviews, June 2011… the book is designed for people who are working in the area and want to learn more about a specific issue. The chapters are written to be relatively independent so that readers can focus on the part of interest for them. Such readers will be grateful for the excellent index and extensive bibliography. … the handbook covers a wide range of topics and will be a valuable reference for researchers in curve-based cryptography. -Steven D. Galbraith, Mathematical Reviews, Issue 2007f.
Diagnosing the Formation of Elliptical Galaxies
Snyder, Gregory F.; Hernquist, L. E.
2014-01-01
A challenge in extragalactic astronomy is that we cannot watch what happens to galaxies before and after they are observed. In particular, it remains debated whether galaxy mergers or internal processes drive supermassive black hole growth, trigger luminous starbursts, and shape the population of galaxies we see today. However, given increasingly available computer resources, it is now possible to predict how galaxies might evolve according to a huge variety of observations. With hydrodynamical simulations followed by dust radiative transfer, I examine the formation of elliptical galaxies through three putative phases: dust-obscured starburst, transition object, and red spheroid. I build spatially and spectrally resolved models to analyze diagnostics of essential processes and evaluate the implications of galaxy interactions. I derive an idealized JWST-accessible mid-infrared diagnostic using mock spectra from simulations of merger-induced starbursts. I use similar models to reconcile the numbers of optically selected post-starburst galaxies in the local universe with expectations given independent estimates of the galaxy merger rate. To conclude, I outline an approach to build a “mock observatory” from large-volume cosmological hydrodynamical simulations, with which observations of many types can be brought to bear to constrain the physics of galaxy formation.
Kim, Joonho; Kim, Seok; Lee, Kimyeong; Park, Jaemo; Vafa, Cumrun
2017-09-01
We study a family of 2d N=(0, 4) gauge theories which describes at low energy the dynamics of E-strings, the M2-branes suspended between a pair of M5 and M9 branes. The gauge theory is engineered using a duality with type IIA theory, leading to the D2-branes suspended between an NS5-brane and 8 D8-branes on an O8-plane. We compute the elliptic genus of this family of theories, and find agreement with the known results for single and two E-strings. The partition function can in principle be computed for arbitrary number of E-strings, and we compute them explicitly for low numbers. We test our predictions against the partially known results from topological strings, as well as from the instanton calculus of 5d Sp(1) gauge theory. Given the relation to topological strings, our computation provides the all genus partition function of the refined topological strings on the canonical bundle over 1/2K3.
A class of variational–hemivariational inequalities of elliptic type
International Nuclear Information System (INIS)
Liu, Zhenhai; Motreanu, Dumitru
2010-01-01
This paper is devoted to the existence of solutions for variational–hemivariational inequalities of elliptic type, with a higher order quasilinear principal part, at resonance as well as at nonresonance. The approach relies on the use of pseudomonotone operators. By means of the notion of Clarke's generalized gradient and the properties of the first eigenfunction of the quasilinear principal part, we also build a Landesman–Lazer theory in the nonsmooth framework of variational–hemivariational inequalities of elliptic type
Connecting Jacobi elliptic functions with different modulus parameters
Indian Academy of Sciences (India)
Most properties of Jacobi elliptic functions found in the literature do not involve any change in the modulus parameter m. For example, the quadratic relations cn2(x, m)=1 − sn2(x, m), dn2(x, m)=1 − msn2(x, m),. (2) and the addition formulas for sn(x + y, m), cn(x + y, m), dn(x + y, m) just involve. Jacobi elliptic functions with the ...
High rank elliptic curves with torsion ℤ/4ℤ.
Khoshnam, Foad; Moody, Dustin
2016-01-01
Working over the field ℚ( t ), Kihara constructed an elliptic curve with torsion group ℤ/4ℤ and five independent rational points, showing the rank is at least five. Following his approach, we give a new infinite family of elliptic curves with torsion group ℤ/4ℤ and rank at least five. This matches the current record for such curves. In addition, we give specific examples of these curves with high ranks 10 and 11.
Development of an Elliptical Trainer Physical Fitness Test
2006-04-02
rear-drive model elliptical trainer for placement in Navy gyms and ships. Despite the availability of the CT 9500 HR elliptical trainer for Navy...waiver for participation in the PRT, and were not on any chronic medications ( steroid inhalants or steroids , anti-inflammatory drugs). One individual was...Naval Region Southwest) to recruit from the general Navy population; (2) posting flyers in area gyms to recruit sailors who have experience using
A Note on Arithmetic Progressions on Quartic Elliptic Curves
Ulas, Maciej
2005-05-01
G. Campbell described a technique for producing infinite families of quartic elliptic curves containing a length-9 arithmetic progression. He also gave an example of a quartic elliptic curve containing a length-12 arithmetic progression. In this note we give a construction of an infinite family of quartics on which there is an arithmetic progression of length 10. Then we show that there exists an infinite family of quartics containing a sequence of length 12.
Radial, sideward and elliptic flow at AGS energies
Indian Academy of Sciences (India)
the sideward flow, the elliptic flow and the radial transverse mass distribution of protons data at. AGS energies. In order to ... data on both sideward and elliptic flow, NL3 model is better at 2 A¡GeV, while NL23 model is at 4–8. A¡GeV. ... port approach RBUU which is based on a coupled set of covariant transport equations for.
Regularity versus singularities for elliptic problems in two dimensions
Beck, Lisa
2009-01-01
In two dimensions every weak solution to a nonlinear elliptic system $\\rm{div} a(x,u,Du)=0$ has H\\"older continuous first derivatives provided that standard continuity, ellipticity and growth assumptions hold with a growth exponent $p \\geq 2$. We give an example showing that this result cannot be extended to the subquadratic case, i.e. that weak solutions are not necessarily continuous if $1< p
On the curious series related to the elliptic integrals
Yakubovich, Semyon
2016-01-01
By using the theory of the elliptic integrals a new method of summation is proposed for a certain class of series and their derivatives involving hyperbolic functions. It is based on the termwise differentiation of the series with respect to the elliptic modulus and integral representations of several of the series in terms of the inverse Mellin transforms related to the Riemann zeta function. The relation with the corresponding case of the Voronoi summation formula is exhibited. The involved...
Second quantization of the elliptic Calogero-Sutherland model
Langmann, Edwin
2001-01-01
We use loop group techniques to construct a quantum field theory model of anyons on a circle and at finite temperature. We find an anyon Hamiltonian providing a second quantization of the elliptic Calogero-Sutherland model. This allows us to prove a remarkable identity which is a starting point for an algorithm to construct eigenfunctions and eigenvalues of the elliptic Calogero-Sutherland Hamiltonian (this algorithm is elaborated elsewhere). This paper contains a detailed introduction, techn...
Cotton-Type and Joint Invariants for Linear Elliptic Systems
Directory of Open Access Journals (Sweden)
A. Aslam
2013-01-01
that Cotton-type invariants derived from these two approaches are identical. Furthermore, Cotton-type and joint invariants for a general system of two linear elliptic equations are also obtained from the Laplace-type and joint invariants for a system of two linear hyperbolic equations equivalent to the system of linear elliptic equations by complex changes of the independent variables. Examples are presented to illustrate the results.
An electrostatic elliptical mirror for neutral polar molecules
Flórez, A. Isabel González; Meek, Samuel A.; Haak, Henrik; Conrad, Horst; Santambrogio, Gabriele; Meijer, Gerard
2011-01-01
Focusing optics for neutral molecules finds application in shaping and steering molecular beams. Here we present an electrostatic elliptical mirror for polar molecules consisting of an array of microstructured gold electrodes deposited on a glass substrate. Alternating positive and negative voltages applied to the electrodes create a repulsive potential for molecules in low-field-seeking states. The equipotential lines are parallel to the substrate surface, which is bent in an elliptical shap...
ELLIPT2D: A Flexible Finite Element Code Written Python
International Nuclear Information System (INIS)
Pletzer, A.; Mollis, J.C.
2001-01-01
The use of the Python scripting language for scientific applications and in particular to solve partial differential equations is explored. It is shown that Python's rich data structure and object-oriented features can be exploited to write programs that are not only significantly more concise than their counter parts written in Fortran, C or C++, but are also numerically efficient. To illustrate this, a two-dimensional finite element code (ELLIPT2D) has been written. ELLIPT2D provides a flexible and easy-to-use framework for solving a large class of second-order elliptic problems. The program allows for structured or unstructured meshes. All functions defining the elliptic operator are user supplied and so are the boundary conditions, which can be of Dirichlet, Neumann or Robbins type. ELLIPT2D makes extensive use of dictionaries (hash tables) as a way to represent sparse matrices.Other key features of the Python language that have been widely used include: operator over loading, error handling, array slicing, and the Tkinter module for building graphical use interfaces. As an example of the utility of ELLIPT2D, a nonlinear solution of the Grad-Shafranov equation is computed using a Newton iterative scheme. A second application focuses on a solution of the toroidal Laplace equation coupled to a magnetohydrodynamic stability code, a problem arising in the context of magnetic fusion research
Aqua/Aura Inclination Adjust Maneuver Series Spring 2018 Planning
Trenholme, Elena; Boone, Spencer
2017-01-01
This will be presented at the International Earth Science Constellation Mission Operations Working Group meeting on December 6-8, 2017 to discuss the Aqua/Aura Spring 2018 Inclination Adjust Maneuver series planning. Presentation has been reviewed and approved by Eric Moyer, ESMO (Earth Science Mission Operations) Deputy Project Manager.
MEASUREMENTS OF DUST EXTINCTION IN HIGHLY INCLINED SPIRAL GALAXIES
JANSEN, RA; KNAPEN, JH; BECKMAN, JE; PELETIER, RF; HES, R
1994-01-01
We study the extinction properties of dust in the well-defined dust lanes of four highly inclined galaxies, using U-, B-, V-, R- and I-band CCD and J- and K'-band near-infrared array images. For three of these galaxies, we could use the symmetry of the underlying light profile to obtain absolute
Motion on an Inclined Plane and the Nature of Science
Pendrill, Ann-Marie; Ekström, Peter; Hansson, Lena; Mars, Patrik; Ouattara, Lassana; Ryan, Ulrika
2014-01-01
Friction is an important phenomenon in everyday life. All children are familiar with playground slides, which may thus be a good starting point for investigating friction. Motion on an inclined plane is a standard physics example. This paper presents an investigation of friction by a group of 11-year olds. How did they plan their investigations?…
Evidences of inclined transpression at the contact between ...
Indian Academy of Sciences (India)
Home; Journals; Journal of Earth System Science; Volume 125; Issue 5. Evidences of inclined ... a right lateral strike-slip component. As a whole, it is suggested that Udayagiri group is thrusted over Vinjamuru group along a westerly dipping thrust plane with a right lateral strike-slip motion and simultaneous E–W contraction.
Inclined Planes and Motion Detectors: A Study of Acceleration.
Tracy, Dyanne M.
2001-01-01
Presents an activity in which students work in cooperative groups and roll balls down inclined planes, collect data with the help of an electronic motion detector, and represent data with a graphing calculator to explore concepts such as mass, gravity, velocity, and acceleration. (Contains 12 references.) (Author/ASK)
The effect of circular bridge piers with different inclination angles ...
Indian Academy of Sciences (India)
c Indian Academy of Sciences. The effect of circular bridge piers with different inclination angles toward downstream on scour. MOHAMMAD VAGHEFI1,∗, MASOUD GHODSIAN2 and. SAEID SALIMI3. 1Department of Civil Engineering, Persian Gulf University, Shahid Mahini Street, P.O. Box: 75169-13817,. Bushehr, Iran.
The inter-relationships between angle of inclination, height and ...
African Journals Online (AJOL)
Experiments were conducted to investigate the dependence of number of sprouted teak (Tectona grandis Linn. F) stumps on the height above root collar and angle of inclination of planted teak stumps. The studies were aim-ed at developing suitable methods of converting teak seedlings into stumps and planting practices to ...
Reconstruction of Galileo Galilei's Experiment: The Inclined Plane
Straulino, S.
2008-01-01
In the "Third Day" of the "Discourses and Mathematical Demonstrations Concerning Two New Sciences" Galileo Galilei describes the famous experiment of the inclined plane and uses it to bring an experimental confirmation to the laws of uniformly accelerated motion. We describe a reconstruction of the experiment and how the results can be used for…
Optimization of PV array inclination in India using ANN estimator ...
Indian Academy of Sciences (India)
Home; Journals; Sadhana; Volume 40; Issue 5. Optimization of PV array inclination in India using ANN estimator: Method comparison study ... Although different non-linear, empirical models have been proposed by different researchers in India, they have too many constraints and needs complex and rigorous computational ...
A layered model for inclined pipe flow of settling slurry
Czech Academy of Sciences Publication Activity Database
Matoušek, Václav; Krupička, Jan; Kesely, Mikoláš
2018-01-01
Roč. 333, June (2018), s. 317-326 ISSN 0032-5910 R&D Projects: GA ČR GA17-14271S Institutional support: RVO:67985874 Keywords : inclined pipe * settling slurry * pressure drop * flow stratification * laboratory loop Impact factor: 2.942, year: 2016
Evidences of inclined transpression at the contact between ...
Indian Academy of Sciences (India)
zone may show different structures or dominance of certain type of structures, depending on whether that part is dominated by strike-slip, dip slip or compression. The present study finds evidences of inclined transpression at the contact between. Udayagiri and Vinjamuru group of NSB, which is the main focus of this paper.
Retrieval of Rayleigh wave ellipticity from ambient vibration recordings
Maranò, Stefano; Hobiger, Manuel; Fäh, Donat
2017-04-01
The analysis of ambient vibrations is a useful tool in microzonation and geotechnical investigations. Ambient vibrations are composed to a large part of surface waves, both Love and Rayleigh waves. One reason to analyse surface waves is that they carry information about the subsurface. The dispersion curve of Rayleigh waves and Love waves can be retrieved using array processing techniques. The Rayleigh wave ellipticity, including the sense of rotation of the particle motion, can also be retrieved using array techniques. These quantities are used in an inversion procedure aimed at obtaining a structural model of the subsurface. The focus of this work is the retrieval of Rayleigh wave ellipticity. We show applications of the maximum likelihood (ML) method presented in Maranò et al. to a number of sites in Switzerland. The sites examined are chosen to reflect a wide range of soil conditions that are of interest in microzonation studies. Using a synthetic wavefield with known structural model, we compare our results with theoretical ellipticity curves and we show the accuracy of the considered algorithm. The sense of rotation of the particle motion (prograde versus retrograde) is also estimated. In addition, we show that by modelling the presence of both Love and Rayleigh waves it is possible to mitigate the disruptive influence of Love waves on the estimation of Rayleigh wave ellipticity. Using recordings from several real sites, we show that it is possible to retrieve the ellipticity curve over a broad range of frequencies. Fundamental modes and higher modes are retrieved. Singularities of the ellipticity, corresponding to a change of the sense of rotation from prograde to retrograde (or vice versa), are detected with great accuracy. Knowledge of Rayleigh wave ellipticity, including the sense of rotation, is useful in several ways. The ellipticity angle allows us to pinpoint accurately the frequency of singularities (i.e. peaks and zeros of the H/V representation of
Conway, Paul; Gawronski, Bertram
2013-02-01
Dual-process theories of moral judgment suggest that responses to moral dilemmas are guided by two moral principles: the principle of deontology states that the morality of an action depends on the intrinsic nature of the action (e.g., harming others is wrong regardless of its consequences); the principle of utilitarianism implies that the morality of an action is determined by its consequences (e.g., harming others is acceptable if it increases the well-being of a greater number of people). Despite the proposed independence of the moral inclinations reflecting these principles, previous work has relied on operationalizations in which stronger inclinations of one kind imply weaker inclinations of the other kind. The current research applied Jacoby's (1991) process dissociation procedure to independently quantify the strength of deontological and utilitarian inclinations within individuals. Study 1 confirmed the usefulness of process dissociation for capturing individual differences in deontological and utilitarian inclinations, revealing positive correlations of both inclinations to moral identity. Moreover, deontological inclinations were uniquely related to empathic concern, perspective-taking, and religiosity, whereas utilitarian inclinations were uniquely related to need for cognition. Study 2 demonstrated that cognitive load selectively reduced utilitarian inclinations, with deontological inclinations being unaffected. In Study 3, a manipulation designed to enhance empathy increased deontological inclinations, with utilitarian inclinations being unaffected. These findings provide evidence for the independent contributions of deontological and utilitarian inclinations to moral judgments, resolving many theoretical ambiguities implied by previous research. (c) 2013 APA, all rights reserved.
Spectrum of 100-kyr glacial cycle: orbital inclination, not eccentricity.
Muller, R A; MacDonald, G J
1997-08-05
Spectral analysis of climate data shows a strong narrow peak with period approximately 100 kyr, attributed by the Milankovitch theory to changes in the eccentricity of the earth's orbit. The narrowness of the peak does suggest an astronomical origin; however the shape of the peak is incompatible with both linear and nonlinear models that attribute the cycle to eccentricity or (equivalently) to the envelope of the precession. In contrast, the orbital inclination parameter gives a good match to both the spectrum and bispectrum of the climate data. Extraterrestrial accretion from meteoroids or interplanetary dust is proposed as a mechanism that could link inclination to climate, and experimental tests are described that could prove or disprove this hypothesis.
Entrepreneurial Inclination Among Business Students: A Malaysian Study
Directory of Open Access Journals (Sweden)
Yet-Mee Lim
2012-11-01
Full Text Available Normal 0 false false false IN X-NONE AR-SA MicrosoftInternetExplorer4 Entrepreneurship has been the fundamental topics of discussion among the politicians, economists, and academics. Business creation is especially critical in developing countries to stimulate economic growth. The present study attempts to examine entrepreneurial inclination among students who are a potential source of entrepreneurs. The fi ndings of the present research study indicate that majority of our business students are not entrepreneurial-inclined. They do not seem to possess strong entrepreneurial characteristics and entrepreneurial skills, and they are not keen in starting a new business. The roles of higher institutes of education and the government in promoting entrepreneurship are discussed.
Advanced topics in the arithmetic of elliptic curves
Silverman, Joseph H
1994-01-01
In the introduction to the first volume of The Arithmetic of Elliptic Curves (Springer-Verlag, 1986), I observed that "the theory of elliptic curves is rich, varied, and amazingly vast," and as a consequence, "many important topics had to be omitted." I included a brief introduction to ten additional topics as an appendix to the first volume, with the tacit understanding that eventually there might be a second volume containing the details. You are now holding that second volume. it turned out that even those ten topics would not fit Unfortunately, into a single book, so I was forced to make some choices. The following material is covered in this book: I. Elliptic and modular functions for the full modular group. II. Elliptic curves with complex multiplication. III. Elliptic surfaces and specialization theorems. IV. Neron models, Kodaira-Neron classification of special fibers, Tate's algorithm, and Ogg's conductor-discriminant formula. V. Tate's theory of q-curves over p-adic fields. VI. Neron's theory of can...
STUDENTS’ ABILITY FOR USING ELLIPTICAL CONSTRUCTION IN SENTENCES
Directory of Open Access Journals (Sweden)
Maria Ramasari
2016-04-01
Full Text Available Grammar is a fundamental thing in a language. The researcher assumes based on her observation that the hardest part of making and writing sentence is to arrange the words in a good sentence. Students are still confused when they are going to arrange the words in right grammar. In mastering grammar, students need time, opportunity, exercise and good teaching of grammar. Unfortunately, grammar skill is still lack attention in teaching and learning process. This research is intended to investigate and describe students’ ability for using elliptical construction in sentences. In this research, the researcher used descriptive method. The data was evaluated and analyzed to find out students’ ability for using elliptical construction in sentences by using percentage formula. There were 34 of 73 students who were in very low category with percentage 46.5%. The result of this research showed that students’ ability for using elliptical construction in sentences to the fourth semester students of English Study Program at Muhammadiyah University of Bengkulu was very low. It meant that the fourth semester English students still had lack knowledge and understanding about grammar: elliptical construction.Keywords: Students’ Ability, Elliptical Construction,and Sentences.
Aqua/Aura Updated Inclination Adjust Maneuver Performance Prediction Model
Boone, Spencer
2017-01-01
This presentation will discuss the updated Inclination Adjust Maneuver (IAM) performance prediction model that was developed for Aqua and Aura following the 2017 IAM series. This updated model uses statistical regression methods to identify potential long-term trends in maneuver parameters, yielding improved predictions when re-planning past maneuvers. The presentation has been reviewed and approved by Eric Moyer, ESMO Deputy Project Manager.
Graphs and matroids weighted in a bounded incline algebra.
Lu, Ling-Xia; Zhang, Bei
2014-01-01
Firstly, for a graph weighted in a bounded incline algebra (or called a dioid), a longest path problem (LPP, for short) is presented, which can be considered the uniform approach to the famous shortest path problem, the widest path problem, and the most reliable path problem. The solutions for LPP and related algorithms are given. Secondly, for a matroid weighted in a linear matroid, the maximum independent set problem is studied.
Drop impact and rebound dynamics on an inclined superhydrophobic surface.
Yeong, Yong Han; Burton, James; Loth, Eric; Bayer, Ilker S
2014-10-14
Due to its potential in water-repelling applications, the impact and rebound dynamics of a water drop impinging perpendicular to a horizontal superhydrophobic surface have undergone extensive study. However, drops tend to strike a surface at an angle in applications. In such cases, the physics governing the effects of oblique impact are not well studied or understood. Therefore, the objective of this study was to conduct an experiment to investigate the impact and rebound dynamics of a drop at various liquid viscosities, in an isothermal environment, and on a nanocomposite superhydrophobic surface at normal and oblique impact conditions (tilted at 15°, 30°, 45°, and 60°). This study considered drops falling from various heights to create normal impact Weber numbers ranging from 6 to 110. In addition, drop viscosity was varied by decreasing the temperature for water drops and by utilizing water-glycerol mixtures, which have similar surface tension to water but higher viscosities. Results revealed that oblique and normal drop impact behaved similarly (in terms of maximum drop spread as well as rebound dynamics) at low normal Weber numbers. However, at higher Weber numbers, normal and oblique impact results diverged in terms of maximum spread, which could be related to asymmetry and more complex outcomes. These asymmetry effects became more pronounced as the inclination angle increased, to the point where they dominated the drop impact and rebound characteristics when the surface was inclined at 60°. The drop rebound characteristics on inclined surfaces could be classified into eight different outcomes driven primarily by normal Weber number and drop Ohnesorge numbers. However, it was found that these outcomes were also a function of the receding contact angle, whereby reduced receding angles yielded tail-like structures. Nevertheless, the contact times of the drops with the coating were found to be generally independent of surface inclination.
Two Mechanisms of Sensorimotor Set Adaptation to Inclined Stance
Directory of Open Access Journals (Sweden)
Kyoung-Hyun Lee
2017-10-01
Full Text Available Orientation of posture relative to the environment depends on the contributions from the somatosensory, vestibular, and visual systems mixed in varying proportions to produce a sensorimotor set. Here, we probed the sensorimotor set composition using a postural adaptation task in which healthy adults stood on an inclined surface for 3 min. Upon returning to a horizontal surface, participants displayed a range of postural orientations – from an aftereffect that consisted of a large forward postural lean to an upright stance with little or no aftereffect. It has been hypothesized that the post-incline postural change depends on each individual’s sensorimotor set: whether the set was dominated by the somatosensory or vestibular system: Somatosensory dominance would cause the lean aftereffect whereas vestibular dominance should steer stance posture toward upright orientation. We investigated the individuals who displayed somatosensory dominance by manipulating their attention to spatial orientation. We introduced a distraction condition in which subjects concurrently performed a difficult arithmetic subtraction task. This manipulation altered the time course of their post-incline aftereffect. When not distracted, participants returned to upright stance within the 3-min period. However, they continued leaning forward when distracted. These results suggest that the mechanism of sensorimotor set adaptation to inclined stance comprises at least two components. The first component reflects the dominant contribution from the somatosensory system. Since the postural lean was observed among these subjects even when they were not distracted, it suggests that the aftereffect is difficult to overcome. The second component includes a covert attentional component which manifests as the dissipation of the aftereffect and the return of posture to upright orientation.
Determination of angle of inclination for optimum power production ...
African Journals Online (AJOL)
This study evaluates the performance of the photovoltaic modules at different tilt angle (angle of inclination) from 5º to 90º. The solar panel of 45 Watts capacity was placed on the manual tracker between the hours of 7:00am and 6:15pm on the geographical location of latitude of 40 55' 58” North and longitude of 60 59' 55” ...
Sagittal x-ray beam deviation at asymmetric inclined diffractors
Czech Academy of Sciences Publication Activity Database
Korytár, D.; Hrdý, Jaromír; Artemiev, Nikolai; Ferrari, C.; Freund, A.
2001-01-01
Roč. 8, - (2001), s. 1136-1139 ISSN 0909-0495 R&D Projects: GA MŠk OK 305; GA MPO PZ-CH/22 Institutional research plan: CEZ:AV0Z1010914 Keywords : x-ray optics * Si(111) W/grooved crystals * inclined diffraction * out-of-diffraction-plane beams * sagittal focusing Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.519, year: 2001
The influence of incline walking on joint mechanics.
Haggerty, Mason; Dickin, D Clark; Popp, Jennifer; Wang, Henry
2014-04-01
Walking is a popular form of exercise and is associated with many health benefits; however, frontal-plane knee joint loading brought about by a large internal knee-abduction moment and cyclic loading could lead to cartilage degeneration over time. Therefore, knee joint mechanics during an alternative walking exercise needs to be analyzed. The purpose of this study was to examine the lower-extremity joint mechanics in the frontal and sagittal planes during incline walking. Fifteen healthy males walked on a treadmill at five gradients (0%, 5%, 10%, 15%, and 20%) at 1.34m/s, and lower-extremity joint mechanics in the frontal and sagittal planes were quantified. The peak internal knee-abduction moment significantly decreased from the level walking condition at all gradients except 5%. Also, a negative relationship between the internal knee-abduction moment and the treadmill gradient was found to exist in 10% increments (0-10%, 5-15%, and 10-20%). The decrease in the internal knee-abduction moment during incline walking could have positive effects on knee joint health such as potentially reducing cartilage degeneration of the knee joint, reducing pain, and decreasing the rate of development of medial tibiofemoral osteoarthritis. This would be beneficial for a knee surgery patient, obese persons, and older adults who are using incline walking for rehabilitation and exercise protocols. Findings from the current study can provide guidance for the development of rehabilitation and exercise prescriptions incorporating incline walking. Copyright © 2014 Elsevier B.V. All rights reserved.
Three-dimensional volumetric display by inclined-plane scanning
Miyazaki, Daisuke; Eto, Takuma; Nishimura, Yasuhiro; Matsushita, Kenji
2003-05-01
A volumetric display system based on three-dimensional (3-D) scanning that uses an inclined two-dimensional (2-D) image is described. In the volumetric display system a 2-D display unit is placed obliquely in an imaging system into which a rotating mirror is inserted. When the mirror is rotated, the inclined 2-D image is moved laterally. A locus of the moving image can be observed by persistence of vision as a result of the high-speed rotation of the mirror. Inclined cross-sectional images of an object are displayed on the display unit in accordance with the position of the image plane to observe a 3-D image of the object by persistence of vision. Three-dimensional images formed by this display system satisfy all the criteria for stereoscopic vision. We constructed the volumetric display systems using a galvanometer mirror and a vector-scan display unit. In addition, we constructed a real-time 3-D measurement system based on a light section method. Measured 3-D images can be reconstructed in the 3-D display system in real time.
Inclined Fiber Pullout from a Cementitious Matrix: A Numerical Study
Directory of Open Access Journals (Sweden)
Hui Zhang
2016-09-01
Full Text Available It is well known that fibers improve the performance of cementitious composites by acting as bridging ligaments in cracks. Such bridging behavior is often studied through fiber pullout tests. The relation between the pullout force vs. slip end displacement is characteristic of the fiber-matrix interface. However, such a relation varies significantly with the fiber inclination angle. In the current work, we establish a numerical model to simulate the entire pullout process by explicitly representing the fiber, matrix and the interface for arbitrary fiber orientations. Cohesive elements endorsed with mixed-mode fracture capacities are implemented to represent the bond-slip behavior at the interface. Contact elements with Coulomb’s friction are placed at the interface to simulate frictional contact. The bond-slip behavior is first calibrated through pull-out curves for fibers aligned with the loading direction, then validated against experimental results for steel fibers oriented at 30 ∘ and 60 ∘ . Parametric studies are then performed to explore the influences of both material properties (fiber yield strength, matrix tensile strength, interfacial bond and geometric factors (fiber diameter, embedment length and inclination angle on the overall pullout behavior, in particular on the maximum pullout load. The proposed methodology provides the necessary pull-out curves for a fiber oriented at a given angle for multi-scale models to study fracture in fiber-reinforced cementitious materials. The novelty lies in its capacity to capture the entire pullout process for a fiber with an arbitrary inclination angle.
Magnetohydrodynamics equilibrium of a self-confined elliptical plasma ball
Energy Technology Data Exchange (ETDEWEB)
Wu, H. (CCAST (World Laboratory) P. O. Box 8730, Beijing 100080 and Institute of Mechanics, Academia Sinica, Beijing, People' s Republic of China (CN)); Oakes, M.E. (Department of Physics, University of Texas at Austin, Austin, Texas 78712 (USA))
1991-08-01
A variational principle is applied to the problem of magnetohydrodynamics (MHD) equilibrium of a self-contained elliptical plasma ball, such as elliptical ball lightning. The principle is appropriate for an approximate solution of partial differential equations with arbitrary boundary shape. The method reduces the partial differential equation to a series of ordinary differential equations and is especially valuable for treating boundaries with nonlinear deformations. The calculations conclude that the pressure distribution and the poloidal current are more uniform in an oblate self-confined plasma ball than that of an elongated plasma ball. The ellipticity of the plasma ball is obviously restricted by its internal pressure, magnetic field, and ambient pressure. Qualitative evidence is presented for the absence of sighting of elongated ball lightning.
Modern cryptography and elliptic curves a beginner's guide
Shemanske, Thomas R
2017-01-01
This book offers the beginning undergraduate student some of the vista of modern mathematics by developing and presenting the tools needed to gain an understanding of the arithmetic of elliptic curves over finite fields and their applications to modern cryptography. This gradual introduction also makes a significant effort to teach students how to produce or discover a proof by presenting mathematics as an exploration, and at the same time, it provides the necessary mathematical underpinnings to investigate the practical and implementation side of elliptic curve cryptography (ECC). Elements of abstract algebra, number theory, and affine and projective geometry are introduced and developed, and their interplay is exploited. Algebra and geometry combine to characterize congruent numbers via rational points on the unit circle, and group law for the set of points on an elliptic curve arises from geometric intuition provided by Bézout's theorem as well as the construction of projective space. The structure of the...
Dirac Particles Emission from An Elliptical Black Hole
Directory of Open Access Journals (Sweden)
Yuant Tiandho
2017-03-01
Full Text Available According to the general theory of relativiy, a black hole is defined as a region of spacetime with super-strong gravitational effects and there is nothing can escape from it. So in the classical theory of relativity, it is safe to say that black hole is a "dead" thermodynamical object. However, by using quantum mechanics theory, Hawking has shown that a black hole may emit particles. In this paper, calculation of temperature of an elliptical black hole when emitting the Dirac particles was presented. By using the complexpath method, radiation can be described as emission process in the tunneling pictures. According to relationship between probability of outgoing particle with the spectrum of black body radiation for fermion particles, temperature of the elliptical black hole can be obtained and it depend on the azimuthal angle. This result also showed that condition on the surface of elliptical black hole is not in thermal equilibrium.
Applications of elliptic Carleman inequalities to Cauchy and inverse problems
Choulli, Mourad
2016-01-01
This book presents a unified approach to studying the stability of both elliptic Cauchy problems and selected inverse problems. Based on elementary Carleman inequalities, it establishes three-ball inequalities, which are the key to deriving logarithmic stability estimates for elliptic Cauchy problems and are also useful in proving stability estimates for certain elliptic inverse problems. The book presents three inverse problems, the first of which consists in determining the surface impedance of an obstacle from the far field pattern. The second problem investigates the detection of corrosion by electric measurement, while the third concerns the determination of an attenuation coefficient from internal data, which is motivated by a problem encountered in biomedical imaging.
Plasma blob generation due to cooperative elliptic instability.
Manz, P; Xu, M; Müller, S H; Fedorczak, N; Thakur, S C; Yu, J H; Tynan, G R
2011-11-04
Using fast-camera measurements the generation mechanism of plasma blobs is investigated in the linear device CSDX. During the ejection of plasma blobs the plasma is dominated by an m=1 mode, which is a counterrotating vortex pair. These flows are known to be subject to the cooperative elliptic instability, which is characterized by a cooperative disturbance of the vortex cores and results in a three-dimensional breakdown of two-dimensional flows. The first experimental evidence of a cooperative elliptic instability preceding the blob-ejection is provided in terms of the qualitative evolution of the vortex geometries and internal wave patterns.
FDM for Elliptic Equations with Bitsadze-Samarskii-Dirichlet Conditions
Directory of Open Access Journals (Sweden)
Allaberen Ashyralyev
2012-01-01
Full Text Available A numerical method is proposed for solving nonlocal boundary value problem for the multidimensional elliptic partial differential equation with the Bitsadze-Samarskii-Dirichlet condition. The first and second-orders of accuracy stable difference schemes for the approximate solution of this nonlocal boundary value problem are presented. The stability estimates, coercivity, and almost coercivity inequalities for solution of these schemes are established. The theoretical statements for the solutions of these nonlocal elliptic problems are supported by results of numerical examples.
UV Visibility of Moderate-Redshift Giant Elliptical Galaxies
Directory of Open Access Journals (Sweden)
Myung-Hyun Rhee
1998-06-01
Full Text Available We show quantitatively whether giant elliptical galaxies would be visible at far UV wavelengths if they were placed at moderate redshift of 0.4-0.5. On the basis of simple cosmological tests, we conclude that giant elliptical galaxies can be detectable upto the redshift of 0.4-0.5 in the proposed GALEX (Galaxy Evolution Explorer Deep Imaging Survey. We also show that obtaining UV color index such as m_1550 - V from upcoming GALEX and SDSS (Sloan Digital Sky Survey observations should be feasible.
Study of medium beta elliptical cavities for CADS
Wen, Liangjian; Zhang, Shenghu; Li, Yongming; Wang, Ruoxu; Guo, Hao; Zhang, Cong; Jia, Huan; Jiang, Tiancai; Li, Chunlong; He, Yuan
2016-02-01
The China Accelerator-Driven Sub-critical System (CADS) is a high intensity proton facility to dispose of nuclear waste and generate electric power. CADS is based on a 1.5 GeV, 10 mA CW superconducting (SC) linac as a driver. The high energy section of the linac is composed of two families of SC elliptical cavities which are designed with geometrical beta 0.63 and 0.82. In this paper, the 650 MHz β=0.63 SC elliptical cavity is studied, including cavity optimization, multipacting, high order modes (HOMs) and generator RF power calculation. Supported by National Natural Science Foundation of China (91426303)
Large N elliptic genus and AdS/CFT Correspondence
International Nuclear Information System (INIS)
Boer, Jan de
1998-01-01
According to one of Maldacena's dualities, type IIB string theory on AdS 3 x S 3 x K3 is equivalent to a certain N = (4, 4) superconformal field theory. In this note we compute the elliptic genus of the boundary theory in the supergravity approximation. A finite quantity is obtained once we introduce a particular exclusion principle. In the regime where the supergravity approximation is reliable, we find exact agreement with the elliptic genus of a sigma model with target space K3 N /S N
N=2 gauged WZW models and the elliptic genus
International Nuclear Information System (INIS)
Henningson, M.
1994-01-01
Witten recently gave further evidence for the conjectured relationship between the A-series of the N = 2 minimal models and certain Landau-Ginzburg models by computing the elliptic genus for the latter. The results agree with those of the N = 2 minimal models, as can be calculated from the known characters of the discrete series representations of the N = 2 superconformal algebra. The N = 2 minimal models also have a lagrangian representation as supersymmetric gauged WZW models. We calculate the elliptic genera, interpreted as a genus one path integral with twisted boundary conditions, for such models and recover the previously known result. (orig.)
Where Does Dark Matter Become Important in Elliptical Galaxies?
Rix, H. -W.
1996-01-01
Recent results from gravitational lensing are combined with new modeling of the stellar velocity distributions in nearby galaxies to probe the connection between the luminous and the dark matter in elliptical galaxies. From analysing a small number of luminous ellipticals the following picture appears to emerge: (1) the best fitting total mass distribution (luminous and dark) leads to a flat rotation curve (v2=RdPhi/dR) from 0.3 to >= 3 effective radii; (2) half the total mass inside the effe...
Centaurus A galaxy, type EO peculiar elliptical, also radio source
2002-01-01
Centaurus A galaxy, type EO peculiar elliptical, also radio source. CTIO 4-meter telescope, 1975. NGC 5128, a Type EO peculiar elliptical galaxy in the constellation Centaurus. This galaxy is one of the most luminous and massive galaxies known and is a strong source of both radio and X-ray radiation. Current theories suggest that the nucleus is experiencing giant explosions involving millions of stars and that the dark band across the galactic disk is material being ejected outward. Cerro Toloto 4-meter telescope photo. Photo credit: National Optical Astronomy Observatories
Transfer coefficients for plate fin and elliptical tube heat exchangers
International Nuclear Information System (INIS)
Saboya, S.M.; Saboya, F.E.M.
1981-01-01
In order to determine transfer coefficients for plate fin and elliptical tube exchangers, mass transfer experiments have been performed using the naphthalene sublimation technique. By means of the heat-mass transfer analogy, the results can be converted to heat transfer results. The transfer coefficients were compared with those for circular tube exchangers and the comparison revealed no major differences. This is a positive outcome, since the use of elliptical tubes may reduce substantially the pressure drop, without affecting the transfer characteristics.(Author) [pt
Hörmander spaces, interpolation, and elliptic problems
Mikhailets, Vladimir A; Malyshev, Peter V
2014-01-01
The monograph gives a detailed exposition of the theory of general elliptic operators (scalar and matrix) and elliptic boundary value problems in Hilbert scales of Hörmander function spaces. This theory was constructed by the authors in a number of papers published in 2005-2009. It is distinguished by a systematic use of the method of interpolation with a functional parameter of abstract Hilbert spaces and Sobolev inner product spaces. This method, the theory and their applications are expounded for the first time in the monographic literature. The monograph is written in detail and in a
Coexistence of a General Elliptic System in Population Dynamics
DEFF Research Database (Denmark)
Pedersen, Michael
2004-01-01
This paper is concerned with a strongly-coupled elliptic system representing a competitive interaction between two species. We give a sufficient condition for the existence of positive solutions. An example is also given to show that there is a coexistence of a steady state if the cross-diffusion......This paper is concerned with a strongly-coupled elliptic system representing a competitive interaction between two species. We give a sufficient condition for the existence of positive solutions. An example is also given to show that there is a coexistence of a steady state if the cross...
An electrostatic elliptical mirror for neutral polar molecules.
González Flórez, A Isabel; Meek, Samuel A; Haak, Henrik; Conrad, Horst; Santambrogio, Gabriele; Meijer, Gerard
2011-11-14
Focusing optics for neutral molecules finds application in shaping and steering molecular beams. Here we present an electrostatic elliptical mirror for polar molecules consisting of an array of microstructured gold electrodes deposited on a glass substrate. Alternating positive and negative voltages applied to the electrodes create a repulsive potential for molecules in low-field-seeking states. The equipotential lines are parallel to the substrate surface, which is bent in an elliptical shape. The mirror is characterized by focusing a beam of metastable CO molecules and the results are compared to the outcome of trajectory simulations.
Frith, J.; Barker, E.; Cowardin, H.; Buckalew, B.; Anz-Meador, P.; Lederer, S.
The National Aeronautics and Space Administration (NASA) Orbital Debris Program Office (ODPO) recently commissioned the Meter Class Autonomous Telescope (MCAT) on Ascension Island with the primary goal of obtaining population statistics of the geosynchronous (GEO) orbital debris environment. To help facilitate this, studies have been conducted using MCAT’s known and projected capabilities to estimate the accuracy and timeliness in which it can survey the GEO environment, including collected weather data and the proposed observational data collection cadence. To optimize observing cadences and probability of detection, on-going work using a simulated GEO debris population sampled at various cadences are run through the Constrained Admissible Region Multi Hypotheses Filter (CAR-MHF). The orbits computed from the results are then compared to the simulated data to assess MCAT’s ability to determine accurately the orbits of debris at various sample rates. The goal of this work is to discriminate GEO and near-GEO objects from GEO transfer orbit objects that can appear as GEO objects in the environmental models due to the short arc observation and an assumed circular orbit. The specific methods and results are presented here.
Directory of Open Access Journals (Sweden)
O. Saka
1998-05-01
Full Text Available Fluxgate magnetometer data recorded at the dip-equator (Huancayo, Peru; 1.44°N, 355.9° in geomagnetic coordinates; 12.1°S, 75.2°W in geographic coordinates; L = 1.00 with higher accuracy of timing (0.1 s and amplitude resolution (0.01 nT were utilized to survey an onset of Pi 2 pulsations in the midnight sector (2100–0100 LT during PROMIS (Polar Region and Outer Magnetosphere International Study periods (1 March–20 June, 1986. It is found that changing field line magnitude and vector as observed by magnetometer on board the synchronous satellites in the midnight sector often takes place simultaneously with the onset of Pi 2 pulsations at the dip-equator. The field disturbances that follow thereafter tend to last for some time both at the geosynchronous altitudes and the dip-equator. In this report, we examine the initial response of the field lines in space, and attempt to classify how the field line vector changed in the meridional plane. Key words. Magnetospheric physics · Magnetospheric configuration and dynamics · MHD waves and instabilities · Plasmasphere
Tugendhat, Tim M.; Schäfer, Björn Malte
2018-02-01
We investigate a physical, composite alignment model for both spiral and elliptical galaxies and its impact on cosmological parameter estimation from weak lensing for a tomographic survey. Ellipticity correlation functions and angular ellipticity spectra for spiral and elliptical galaxies are derived on the basis of tidal interactions with the cosmic large-scale structure and compared to the tomographic weak lensing signal. We find that elliptical galaxies cause a contribution to the weak-lensing dominated ellipticity correlation on intermediate angular scales between ℓ ≃ 40 and ℓ ≃ 400 before that of spiral galaxies dominates on higher multipoles. The predominant term on intermediate scales is the negative cross-correlation between intrinsic alignments and weak gravitational lensing (GI-alignment). We simulate parameter inference from weak gravitational lensing with intrinsic alignments unaccounted; the bias induced by ignoring intrinsic alignments in a survey like Euclid is shown to be several times larger than the statistical error and can lead to faulty conclusions when comparing to other observations. The biases generally point into different directions in parameter space, such that in some cases one can observe a partial cancellation effect. Furthermore, it is shown that the biases increase with the number of tomographic bins used for the parameter estimation process. We quantify this parameter estimation bias in units of the statistical error and compute the loss of Bayesian evidence for a model due to the presence of systematic errors as well as the Kullback-Leibler divergence to quantify the distance between the true model and the wrongly inferred one.
Tugendhat, Tim M.; Schäfer, Björn Malte
2018-05-01
We investigate a physical, composite alignment model for both spiral and elliptical galaxies and its impact on cosmological parameter estimation from weak lensing for a tomographic survey. Ellipticity correlation functions and angular ellipticity spectra for spiral and elliptical galaxies are derived on the basis of tidal interactions with the cosmic large-scale structure and compared to the tomographic weak-lensing signal. We find that elliptical galaxies cause a contribution to the weak-lensing dominated ellipticity correlation on intermediate angular scales between ℓ ≃ 40 and ℓ ≃ 400 before that of spiral galaxies dominates on higher multipoles. The predominant term on intermediate scales is the negative cross-correlation between intrinsic alignments and weak gravitational lensing (GI-alignment). We simulate parameter inference from weak gravitational lensing with intrinsic alignments unaccounted; the bias induced by ignoring intrinsic alignments in a survey like Euclid is shown to be several times larger than the statistical error and can lead to faulty conclusions when comparing to other observations. The biases generally point into different directions in parameter space, such that in some cases one can observe a partial cancellation effect. Furthermore, it is shown that the biases increase with the number of tomographic bins used for the parameter estimation process. We quantify this parameter estimation bias in units of the statistical error and compute the loss of Bayesian evidence for a model due to the presence of systematic errors as well as the Kullback-Leibler divergence to quantify the distance between the true model and the wrongly inferred one.
Tun Myat Aung; Ni Ni Hla
2017-01-01
Abstract—The security of elliptic curve cryptosystems depends on the difficulty of solving the Elliptic Curve Discrete Log Problem (ECDLP). Elliptic curves with large group order are used for elliptic curve cryptosystems not to solve ECDLP. We implement elliptic curve arithmetic operations by using java BigInteger class to study and analyze any elliptic curve cryptographic protocol under large integer for prime field and binary field.
Existence of positive weak solutions for a class of singular elliptic equations
Directory of Open Access Journals (Sweden)
Li Xia
2011-08-01
Full Text Available In this note, we are concerned with positive solutions for a class of singular elliptic equations. Under some conditions, we obtain weak solutions for the equations by elliptic regularization method and sub-super solution method.
Self collision avoidance for humanoids using circular and elliptical capsule bounding volumes
CSIR Research Space (South Africa)
Dube, C
2013-09-01
Full Text Available This paper presents a self collision avoidance scheme for humanoid robots using elliptical and circular capsules as collision bounding volumes. A capsule is defined as an elliptical or circular cylinder capped with ellipsoids or spheres respectively...
Model of the humanoid body for self collision detection based on elliptical capsules
CSIR Research Space (South Africa)
Dube, C
2011-12-01
Full Text Available This paper presents a self collision detection scheme for humanoid robots using elliptical and circular capsules as bounding volumes. A capsule is defined as an elliptical or circular cylinder capped with ellipsoids or spheres respectively...
Efficient method for finding square roots for elliptic curves over OEF
CSIR Research Space (South Africa)
Abu-Mahfouz, Adnan M
2009-01-01
Full Text Available Elliptic curve cryptosystems like others public key encryption schemes, require computing a square roots modulo a prime number. The arithmetic operations in elliptic curve schemes over Optimal Extension Fields (OEF) can be efficiently computed...
Study on the tool wear of 3-D elliptical vibration cutting
J. Lin; X. Jing; M. Lu; Y. Gu; J. Han
2017-01-01
As always, the rapid wear of tools was one of the key factors limiting the precise turning of difficult-to-machine materials with diamond tool. 3-D elliptical vibration cutting has inherited many advantages of elliptical vibration cutting, such as the intermittent cutting property and friction reverse property. However, studies on the tool wear of three-dimensional elliptical vibration cutting has not been reported yet. The formation principle of 3-D cutting elliptical traje...
Sex Differences in Incline-Walking among Humans.
Wall-Scheffler, Cara M
2015-12-01
Previous research has shown that people tend to walk around the speed that minimizes energy consumption when traveling a given distance. It has further been shown that men and women have different speeds that minimize energy and that women will choose slower speeds when the activity itself is a high-rate activity (e.g. carrying a load). Here we investigate what men and women will do when given a high rate walking activity, namely walking on an inclined surface. Fourteen people (nine men and five women) walked at four speeds on a level treadmill and four speeds on an inclined treadmill while their metabolic rate, kinematics and core temperature were monitored. Following the data collection, participants were asked to identify their ‘preferred’ walking speed at each of the conditions. Cost of transport (CoT) curves were calculated for each individual, and the delta between the preferred and the ‘optimal’ speeds were calculated. People chose to walk at slightly slower speeds on the level; there was minimal change in the cost to walk at these slower speeds. Women walked at absolutely slower speeds on the incline than men (P=0.06) and had significantly larger speed deltas (P=0.02), thus choosing to walk at slower rate speeds. Women also showed a significant relationship between the rate of activity and core temperature, whereas men did not. This is consistent with other research showing that women choose behavioral strategies to minimize body temperature changes. © The Author 2015. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.
Flame spread over inclined electrical wires with AC electric fields
Lim, Seung J.
2017-07-21
Flame spread over polyethylene-insulated electrical wires was studied experimentally with applied alternating current (AC) by varying the inclination angle (θ), applied voltage (VAC), and frequency (fAC). For the baseline case with no electric field applied, the flame spread rate and the flame width of downwardly spreading flames (DSFs) decreased from the horizontal case for −20° ≤ θ < 0° and maintained near constant values for −90° ≤ θ < −20°, while the flame spread rate increased appreciably as the inclination angle of upwardly spreading flames (USFs) increased. When an AC electric field was applied, the behavior of flame spread rate in DSFs (USFs) could be classified into two (three) sub-regimes characterized by various functional dependences on VAC, fAC, and θ. In nearly all cases of DSFs, a globular molten polyethylene formed ahead of the spreading flame edge, occasionally dripping onto the ground. In these cases, an effective flame spread rate was defined to represent the burning rate by measuring the mass loss due to dripping. This effective spread rate was independent of AC frequency, while it decreased linearly with voltage and was independent of the inclination angle. In DSFs, when excessively high voltage and frequency were applied, the dripping led to flame extinction during propagation and the extinction frequency correlated well with applied voltage. In USFs, when high voltage and frequency were applied, multiple globular molten PEs formed at several locations, leading to ejections of multiple small flame segments from the main flame, thereby reducing the flame spread rate, which could be attributed to the electrospray phenomenon.
Implementing parallel elliptic solver on a Beowulf cluster
Directory of Open Access Journals (Sweden)
Marcin Paprzycki
1999-12-01
Full Text Available In a recent paper cite{zara} a parallel direct solver for the linear systems arising from elliptic partial differential equations has been proposed. The aim of this note is to present the initial evaluation of the performance characteristics of this algorithm on Beowulf-type cluster. In this context the performance of PVM and MPI based implementations is compared.
Magnetization curves for non-elliptic cylindrical samples in a ...
Indian Academy of Sciences (India)
Using recent results for the surface current density on cylindrical surfaces of arbitrary cross-section producing uniform interior magnetic ﬁeld and an assumed set of ﬂux-fronts, solutions of Bean's critical state model for cylindrical samples with non-elliptic cross-section are presented. Magnetization hysteresis loops for two ...
Transfer coefficients in elliptical tubes and plate fin heat exchangers
International Nuclear Information System (INIS)
Saboya, S.M.
1979-09-01
Mean transfer coefficients in elliptical tubes and plate fin heat exchangers were determined by application of heat and mass transfer analogy in conjunction with the naphthalene sublimation technique. The transfer coefficients are presented in a dimensionless form as functions of the Reynolds number. By using the least squares method analytical expressions for the transfer coefficients were determined with low scattering. (E.G.) [pt
Magnetization curves for non-elliptic cylindrical samples in a ...
Indian Academy of Sciences (India)
Abstract. Using recent results for the surface current density on cylindrical surfaces of arbitrary cross-section producing uniform interior magnetic field and an assumed set of flux-fronts, solutions of Bean's critical state model for cylindrical samples with non-elliptic cross-section are presented. Magnetization hysteresis loops ...
Cross-phase modulational instability in an elliptical birefringent fiber ...
Indian Academy of Sciences (India)
Cross-phase modulational instability in an elliptical birefringent ﬁber with higher order nonlinearity and dispersion. R Ganapathy V C Kuriakose. Research Articles Volume 58 Issue 4 April 2002 pp 669- ... Keywords. Cross-phase modulational instability; normal dispersion; group velocity mismatch; birefringent optical ﬁber.
Diffraction and Dirchlet problem for parameter-elliptic convolution ...
African Journals Online (AJOL)
In this paper we evaluate the difference between the inverse operators of a Dirichlet problem and of a diffraction problem for parameter-elliptic convolution operators with constant symbols. We prove that the inverse operator of a Dirichlet problem can be obtained as a limit case of such a diffraction problem. Quaestiones ...
Spectral results for mixed problems and fractional elliptic operators,
DEFF Research Database (Denmark)
Grubb, Gerd
2015-01-01
and the regularity of eigenfunctions is described. In the second part, we apply this in a study of realizations A χ,Σ+ in L 2( Ω ) of mixed problems for a second-order strongly elliptic symmetric differential operator A on a bounded smooth set Ω ⊂ R n; here the boundary ∂Ω=Σ is partioned smoothly into Σ...
Explosive solutions of elliptic equations with absorption and non ...
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
N. , provided that p, q are non-negative continuous functions so that any zero ofp is surrounded by a surface strictly included in on which p is positive. Under additional hypotheses on p we deduce the existence of solutions if is unbounded. Keywords. Explosive solution; semilinear elliptic problem; entire solution; maximum.
Dynamic stress intensity factors for a longitudinal semi-elliptical ...
African Journals Online (AJOL)
elliptical crack in a thick-walled cylinder subjected to transient dynamic stresses. First, the problem of dynamic elasticity in a thick-walled cylinder is solved analytically using the finite Hankel transform. Transient pressure is assumed to act on ...
Acoustic scattering by multiple elliptical cylinders using collocation multipole method
International Nuclear Information System (INIS)
Lee, Wei-Ming
2012-01-01
This paper presents the collocation multipole method for the acoustic scattering induced by multiple elliptical cylinders subjected to an incident plane sound wave. To satisfy the Helmholtz equation in the elliptical coordinate system, the scattered acoustic field is formulated in terms of angular and radial Mathieu functions which also satisfy the radiation condition at infinity. The sound-soft or sound-hard boundary condition is satisfied by uniformly collocating points on the boundaries. For the sound-hard or Neumann conditions, the normal derivative of the acoustic pressure is determined by using the appropriate directional derivative without requiring the addition theorem of Mathieu functions. By truncating the multipole expansion, a finite linear algebraic system is derived and the scattered field can then be determined according to the given incident acoustic wave. Once the total field is calculated as the sum of the incident field and the scattered field, the near field acoustic pressure along the scatterers and the far field scattering pattern can be determined. For the acoustic scattering of one elliptical cylinder, the proposed results match well with the analytical solutions. The proposed scattered fields induced by two and three elliptical–cylindrical scatterers are critically compared with those provided by the boundary element method to validate the present method. Finally, the effects of the convexity of an elliptical scatterer, the separation between scatterers and the incident wave number and angle on the acoustic scattering are investigated.
On group orders of retional points of elliptic curves | Weng ...
African Journals Online (AJOL)
We consider elliptic curves without complex multiplication defined over the rationals or with complex multiplication defined over the Hilbert class field of the endomorphism ring. We examine the distribution of almost prime group orders of these curves when reduced modulo a prime ideal. Mathematics Subject Classification ...
hp Spectral element methods for three dimensional elliptic problems ...
Indian Academy of Sciences (India)
exponential convergence. A method for obtaining a numerical solution to exponential accuracy for elliptic prob- lems on non-smooth domains in R2 was first .... The organization of this paper is as follows. In §2, we introduce the problem under.
Multiplicity of nontrivial solutions for elliptic equations with ...
Indian Academy of Sciences (India)
2Département de Mathematiques, Université de Perpignan, 66860 Perpignan, France. 3Department of Mathematics, National Technical University, Zografou Campus,. Athens 15780, Greece. E-mail: npapg@math.ntua.gr. MS received 15 March 2004; revised 22 February 2005. Abstract. We consider a semilinear elliptic ...
Uniqueness of positive solutions for cooperative Hamiltonian elliptic systems
Directory of Open Access Journals (Sweden)
Junping Shi
2016-03-01
Full Text Available The uniqueness of positive solution of a semilinear cooperative Hamiltonian elliptic system with two equations is proved for the case of sublinear and superlinear nonlinearities. Implicit function theorem, bifurcation theory, and ordinary differential equation techniques are used in the proof.
hp Spectral element methods for three dimensional elliptic problems ...
Indian Academy of Sciences (India)
125, No. 3, August 2015, pp. 413–447. c Indian Academy of Sciences h-p Spectral element methods for three dimensional elliptic problems on non-smooth domains, Part-II: Proof of stability theorem. P DUTT1, AKHLAQ HUSAIN2,∗, A S VASUDEVA MURTHY3 and C S UPADHYAY4. 1Department of Mathematics & Statistics ...
Dynamics of globular cluster systems in elliptical galaxies
Romanowsky, AJ; Geisler, D; Grebel, EK; Minniti, D
2002-01-01
One of the most promising avenues for exploring the dynamics of the outer parts of elliptical galaxies involves using bright discrete objects as kinematical tracers: globular clusters and planetary nebulae. As large data sets are becoming available, rigorous dynamical analyses are needed to
A dearth of dark matter in ordinary elliptical galaxies
Romanowsky, AJ; Douglas, NG; Arnaboldi, M; Kuijken, K; Merrifield, MR; Napolitano, NR; Capaccioli, M; Freeman, KC
2003-01-01
The kinematics of the outer parts of three intermediate-luminosity elliptical galaxies were studied with the Planetary Nebula Spectrograph. The galaxies' velocity-dispersion profiles were found to decline with the radius, and dynamical modeling of the data indicates the presence of little if any
Arithmetical Fourier and Limit values of elliptic modular functions
Indian Academy of Sciences (India)
2
Science Research Plan (Program No.SK2014-01-08) and by Science Research. Project of Shaanxi Provincial Department of Education(Program No. 16JM1265 and 16JK1238). References. [1] N. Wang, On Riemann's posthumous Fragment II on the limit values of elliptic modular functions, Ramanujan J., 24 (2011), ...
Distribution of some sequences of points on elliptic curves
DEFF Research Database (Denmark)
Lange, Tanja; Shparlinski, Igor
2007-01-01
We estimate character sums over points on elliptic curves over a finite field of q elements. Pseudorandom sequences can be constructed by taking linear combinations with small coefficients (for example, from the set {−1, 0, 1}) of a fixed vector of points, which forms the seed of the generator. We...
Multiplicity of nontrivial solutions for elliptic equations with ...
Indian Academy of Sciences (India)
We consider a semilinear elliptic equation with a nonsmooth, locally Lipschitz potential function (hemivariational inequality). Our hypotheses permit double resonance at infinity and at zero (double-double resonance situation). Our approach is based on the nonsmooth critical point theory for locally Lipschitz functionals and ...
Homogenization of Elliptic Differential Equations in One-Dimensional Spaces
Grammel, G.
2007-01-01
Linear elliptic differential equations with periodic coefficients in one-dimensional domains are considered. The approximation properties of the homogenized system are investigated. For $H^{-1}$ -data, it turns out that the order of approximation is strongly related to the decay of the Fourier coefficients of the $L^{2}$ -functions involved.
Extension theory for elliptic partial differential operators with pseudodifferential methods
DEFF Research Database (Denmark)
Grubb, Gerd
2012-01-01
This is a short survey on the connection between general extension theories and the study of realizations of elliptic operators A on smooth domains in R^n, n >1. The theory of pseudodifferential boundary problems has turned out to be very useful here, not only as a formulational framework, but also...
Infinitely many sign-changing solutions of an elliptic problem ...
Indian Academy of Sciences (India)
Infinitely many sign-changing solutions of an elliptic problem involving critical Sobolev and Hardy–Sobolev exponent. MOUSOMI ... Sign-changing solution; multiple critical exponent; Hardy-Sobolev; infinitely many solutions. Abstract. We study the existence and multiplicity of sign-changing solutions of the following equation.
Infinitely many sign-changing solutions of an elliptic problem ...
Indian Academy of Sciences (India)
MOUSOMI BHAKTA
Infinitely many sign-changing solutions of an elliptic problem involving critical Sobolev and Hardy–Sobolev exponent. MOUSOMI BHAKTA. Department of Mathematics, Indian Institute of Science Education and Research,. Pashan, Pune 411 008, India. E-mail: mousomi@iiserpune.ac.in. MS received 27 May 2015; revised ...
Maximal saddle solution of a nonlinear elliptic equation involving the ...
Indian Academy of Sciences (India)
Abstract. A saddle solution is called maximal saddle solution if its absolute value is not smaller than those absolute values of any solutions that vanish on the Simons cone. C = {s = t} and have the same sign as s − t. We prove the existence of a maximal saddle solution of the nonlinear elliptic equation involving the ...
Superconvergence for tetrahedral quadratic finite element methods for elliptic equations
Brandts, J.H.; Krizek, M.
2005-01-01
For a model elliptic boundary value problem we will prove that on strongly regular families of uniform tetrahedral partitions of the domain, the gradient of the quadratic finite element approximation is superclose to the gradient of the quadratic Lagrange interpolant of the exact solution. This
Spatial distribution of dust in the shell elliptical NGC 5982
del Burgo, C.; Carter, D.; Sikkema, G.
Aims. Shells in Ellipticals are peculiar faint sharp edged features that are thought to be formed by galaxy mergers. We determine the shell and dust distributions, and colours of a well-resolved shell and the underlying galaxy in NGC 5982, and compare the spatial distributions of the dust and gas
Quantifying complex shapes: elliptical fourier analysis of octocoral sclerites.
Carlo, Joseph M; Barbeitos, Marcos S; Lasker, Howard R
2011-06-01
Species descriptions of most alcyonacean octocorals rely heavily on the morphology of sclerites, the calcium carbonate spicules embedded in the soft tissue. Sclerites provide taxonomic characters for species delineation but require qualitative descriptions, which introduce ambiguities in recognizing morphological features. Elliptical Fourier analysis of the outline of sclerites was used to quantify the morphology of eight species of gorgoniid octocoral in the genus Pseudopterogorgia. Sclerites from one to seven colonies of each species were compared. Scaphoids and spindles were examined separately; rods and octoradiates were excluded from the analyses because of their morphologic similarity across all species. Discriminant analysis of elliptical Fourier descriptors (EFDs) was used to determine whether the elliptical Fourier analysis could be used to identify the specimens. Sclerites were highly variable even within a single colony. Correct species assignments of individual sclerites were greater than 50% for both scaphoids and spindles. Species assignments based on averages of the EFDs for each colony approached 90%. Elliptical Fourier analysis quantifies morphological differences between species and measures colony variance in sclerite size and shape among colonies and species. Phylogenetic analysis based on EFDs did not capture monophyletic groups. The quantification of complex shapes such as sclerites provides an important tool in alpha taxonomy but may be less useful in phylogenetic analyses.
GRAVITATIONAL IMAGING BY ELLIPTIC GALAXIES - THE EFFECTS OF DARK HALOS
BREIMER, TG; SANDERS, RH
It has been claimed that some gravitational lenses in which a background quasar is multiply-imaged by a single foreground galaxy support the existence of dark massive halos in elliptical galaxies. We reexamine this claim by considering the lensing effects of spherical galaxies with and without a
Recombination plus fragmentation model at RHIC: elliptic flow
Energy Technology Data Exchange (ETDEWEB)
Nonaka, C [Department of Physics, Duke University, Durham, NC 27708 (United States); Fries, R J [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Mueller, B [Department of Physics, Duke University, Durham, NC 27708 (United States); Bass, S A [Department of Physics, Duke University, Durham, NC 27708 (United States); RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973 (United States); Asakawa, M [Department of Physics, Osaka University, Toyonaka 560-0043 (Japan)
2005-04-01
We discuss hadron production in relativistic heavy-ion collisions in the framework of the recombination and fragmentation model. We propose elliptic flow as a useful tool for exploring final interactions of resonances, the hadron structure of exotic particles and the phase structure of the reaction.
Maximal saddle solution of a nonlinear elliptic equation involving the ...
Indian Academy of Sciences (India)
Home; Journals; Proceedings – Mathematical Sciences; Volume 124; Issue 1. Maximal Saddle ... -Laplacian; maximal saddle solution; monotone iteration methods. ... We prove the existence of a maximal saddle solution of the nonlinear elliptic equation involving the -Laplacian, by using the method of monotone iteration,.
Radial, sideward and elliptic flow at AGS energies
Indian Academy of Sciences (India)
Abstract. We study the baryon transverse in-plane (sideward) and elliptic flow from SIS to AGS energies for Au+Au collisions in a relativistic dynamical simulation model that includes all baryon resonances up to a mass of 2 GeV as well as string degrees of freedom for the higher mass continuum. There are two factors which ...
Existence of positive solutions to semilinear elliptic problems with ...
Indian Academy of Sciences (India)
57
Abstract. In this paper, a semilinear elliptic equation with a nonlinear boundary condition and a per- turbation in the reaction term is studied. The existence of a positive solution and another non-zero solution to the problem is proved when 1λ1 is small enough without any specific as- sumptions on the perturbation term.
Multiple solutions for inhomogeneous nonlinear elliptic problems arising in astrophyiscs
Directory of Open Access Journals (Sweden)
Marco Calahorrano
2004-04-01
Full Text Available Using variational methods we prove the existence and multiplicity of solutions for some nonlinear inhomogeneous elliptic problems on a bounded domain in $mathbb{R}^n$, with $ngeq 2$ and a smooth boundary, and when the domain is $mathbb{R}_+^n$
Radial, sideward and elliptic flow at AGS energies
Indian Academy of Sciences (India)
Home; Journals; Pramana – Journal of Physics; Volume 61; Issue 5. Radial, sideward and elliptic ... the higher mass continuum. There are two factors which dominantly determine the baryon ﬂow at these energies: the momentum dependence of the scalar and vector potentials and the resonance-string degrees of freedom.
Optimization of elliptic neutron guides for triple-axis spectroscopy
International Nuclear Information System (INIS)
Janoschek, M.; Boeni, P.; Braden, M.
2010-01-01
In the last decade the performance of neutron guides for the transport of neutrons has been significantly increased. The most recent developments have shown that elliptic guide systems can be used to focus neutron beams while simultaneously reducing the number of neutron reflections, hence, leading to considerable gains in neutron flux. We have carried out Monte-Carlo simulations for a new triple-axis spectrometer that will be built at the end position of the conventional cold guide NL-1 in the neutron guide hall of the research reactor FRM-II in Munich, Germany. Our results demonstrate that an elliptic guide section at the end of a conventional guide can be used to at least maintain the total neutron flux onto the sample, while significantly improving the energy resolution of the spectrometer. The simulation further allows detailed insight how the defining parameters of an elliptic guide have to be chosen to obtain optimum results. Finally, we show that the elliptic guide limits losses in the neutron flux that generally arise at the gaps, where the monochromator system of the upstream instrument is situated.
Orthonormal polynomials for elliptical wavefronts with an arbitrary orientation.
Díaz, José A; Navarro, Rafael
2014-04-01
We generalize the analytical form of the orthonormal elliptical polynomials for any arbitrary aspect ratio to arbitrary orientation and give expression for them up to the 4th order. The utility of the polynomials is demonstrated by obtaining the expansion up to the 8th order in two examples of an off-axis wavefront exiting from an optical system with a vignetted pupil.
influence of some variable parameters on horizontal elliptic micro
African Journals Online (AJOL)
temidayo
2013-07-02
Jul 2, 2013 ... INFLUENCE OF SOME VARIABLE PARAMETERS ON. HORIZONTAL ELLIPTIC MICRO-CHANNELS. WITH INTERNAL LONGITUDINAL FINS. I. K. Adegun1*, T. S. Jolayemi2, O. O. Olayemi3, O. T. Popoola4. 1,3,4DEPARTMENT OF MECHANICAL ENGINEERING, FACULTY OF ENGINEERING AND ...
Influence of Some Variable Parameters on Horizontal Elliptic Micro ...
African Journals Online (AJOL)
The study investigates the laminar flow and heat transfer characteristics in elliptic micro-channels of varying axis ratios and with internal longitudinal fins, operating in a region that is hydrodynamically and thermally fully developed; purposely to determine the effects of some salient fluid and geometry parameters such as ...
Type-2 fuzzy elliptic membership functions for modeling uncertainty
DEFF Research Database (Denmark)
Kayacan, Erdal; Sarabakha, Andriy; Coupland, Simon
2018-01-01
Whereas type-1 and type-2 membership functions (MFs) are the core of any fuzzy logic system, there are no performance criteria available to evaluate the goodness or correctness of the fuzzy MFs. In this paper, we make extensive analysis in terms of the capability of type-2 elliptic fuzzy MFs in m...
Radial solutions to semilinear elliptic equations via linearized operators
Directory of Open Access Journals (Sweden)
Phuong Le
2017-04-01
Full Text Available Let $u$ be a classical solution of semilinear elliptic equations in a ball or an annulus in $\\mathbb{R}^N$ with zero Dirichlet boundary condition where the nonlinearity has a convex first derivative. In this note, we prove that if the $N$-th eigenvalue of the linearized operator at $u$ is positive, then $u$ must be radially symmetric.
Continuous rearrangement and symmetry of solutions of elliptic ...
Indian Academy of Sciences (India)
nonnegative solutions of some semilinear elliptic problems in symmetric domains satisfy a weak, `local' kind .... This type of continuous rearrangement can be used to prove the symmetry of local minimizers for certain .... of functions u P LpЕΩЖ having generalized partial derivatives uxi P LpЕΩЖ, i И 1Y ... Y n, and we write.
Connecting Jacobi elliptic functions with different modulus parameters
Indian Academy of Sciences (India)
'cn' formula involves alternating + and − signs, and the even p 'sn' formula has a product of p terms. In fact, there are also several interesting additional alternative forms for the above results which follow from use of several identities involving. Jacobi elliptic functions which we have recently discovered [9–11]. For instance ...
On the elliptic flow for nearly symmetric collisions and nuclear ...
Indian Academy of Sciences (India)
10Ne20+13Al27, 18Ar40+21Sc45, 30Zn64+28Ni58, 36Kr86+41Nb93) using the quantum molecular dynamics (QMD) model. General features of elliptic ﬂow are investigated with the help of theoretical simulations. The simulations are ...
Articulator-related registration and analysis of sagittal condylar inclination
Čimić, Samir; Kraljević Šimunković, Sonja; Simonić Kocijan, Sunčana; Matijević, Jurica; Dulčić, Nikša; Ćatić, Amir
2015-01-01
The purpose of this investigation was to study sagittal condylar inclination values within a uniform sample (Angle class I occlusion) using ‘articulator-related registration’ and Camper’s plane as a reference plane. The study was performed on a sample of 58 Angle class I subjects (mean age 25.1, SD 3.1). Measurements were performed with an ultrasonic jaw tracking device with six degrees of freedom. After a paraocclusal tray was fixed in the mouth, each subject had to make three protrusive ...
Mining adjacent inclined coal seams of varying thickness
Energy Technology Data Exchange (ETDEWEB)
Batmanov, Yu.K.; Bakhtin, A.F.; Bulavka, E.I.
1980-01-01
In the Donbass coal basin a large number of thin coal seams located near other thicker coal seams are left. It is suggested that coal output from the Donbass could be increased by 100% and cost of mining could be lowered by 0.4-1.1 roubles per 1 ton of coal if thinner coal seams were also mined. Mining methods in the Donbass are analyzed from the point of view of reducing the cost of mining and increasing coal production. Recommendations on methods of mining thin inclined coal seams are given. (6 refs.) (In Russian)
Rational interpolation to solutions of Riccati difference equations on elliptic lattices
Magnus, Alphonse P.
2009-12-01
It is shown how to define difference equations on particular lattices {xn}, , where the xns are values of an elliptic function at a sequence of arguments in arithmetic progression (elliptic lattice). Solutions to special difference equations (elliptic Riccati equations) have remarkable simple (!) interpolatory continued fraction expansions.
Stellar populations as a function of radius in giant elliptical galaxies
Peletier, Reynier F.; Valentijn, Edwin A.
Accurate surface photometry has been obtained in J and K for 12 giant elliptical galaxies. Ellipses have been fitted, to obtain luminosity, ellipticity, and major axis position angle profiles. The results have been combined with visual profiles from CCD observations. It is found that elliptical
An explicit solution of the (quantum) elliptic Calogero-Sutherland model
Langmann, Edwin
2004-01-01
We present explicit formulas for the eigenvalues and eigenfunctions of the elliptic Calogero-Sutherland (eCS) model as formal power series to all orders in the nome of the elliptic functions, for arbitrary values of the (positive) coupling constant and particle number. Our solution gives explicit formulas for an elliptic deformation of the Jack polynomials.
3-D sensitivity kernels of the Rayleigh wave ellipticity
Maupin, Valérie
2017-10-01
The ellipticity of the Rayleigh wave at the surface depends on the seismic structure beneath and in the vicinity of the seismological station where it is measured. We derive here the expression and compute the 3-D kernels that describe this dependence with respect to S-wave velocity, P-wave velocity and density. Near-field terms as well as coupling to Love waves are included in the expressions. We show that the ellipticity kernels are the difference between the amplitude kernels of the radial and vertical components of motion. They show maximum values close to the station, but with a complex pattern, even when smoothing in a finite-frequency range is used to remove the oscillatory pattern present in mono-frequency kernels. In order to follow the usual data processing flow, we also compute and analyse the kernels of the ellipticity averaged over incoming wave backazimuth. The kernel with respect to P-wave velocity has the simplest lateral variation and is in good agreement with commonly used 1-D kernels. The kernels with respect to S-wave velocity and density are more complex and we have not been able to find a good correlation between the 3-D and 1-D kernels. Although it is clear that the ellipticity is mostly sensitive to the structure within half-a-wavelength of the station, the complexity of the kernels within this zone prevents simple approximations like a depth dependence times a lateral variation to be useful in the inversion of the ellipticity.
Luminosity dependence in the Fundamental Plane projections of elliptical galaxies
Desroches, Louis-Benoit; Quataert, Eliot; Ma, Chung-Pei; West, Andrew A.
2007-05-01
We analyse the Fundamental Plane projections of elliptical galaxies as a function of luminosity, using a sample of ~80000 galaxies drawn from Data Release 4 (DR4) of the Sloan Digital Sky Survey (SDSS). We separate brightest cluster galaxies (BCGs) from our main sample and reanalyse their photometry due to a problem with the default pipeline sky subtraction for BCGs. The observables we consider are effective radius (Re), velocity dispersion (σ), dynamical mass (Mdyn ~ Reσ2), effective density (σ2/R2e) and effective surface brightness (μe). With the exception of the L -Mdyn correlation, we find evidence of variations in the slope (i.e. the power-law index) of the Fundamental Plane projections with luminosity for our normal elliptical galaxy population. In particular, the radius-luminosity and Faber-Jackson relations are steeper at high luminosity relative to low luminosity, and the more luminous ellipticals become progressively less dense and have lower surface brightnesses than lower luminosity ellipticals. These variations can be understood as arising from differing formation histories, with more luminous galaxies having less dissipation. Data from the literature and our reanalysis of BCGs show that BCGs have radius-luminosity and Faber-Jackson relations steeper than the brightest non-BCG ellipticals in our sample, consistent with significant growth of BCGs via dissipationless mergers. The variations in slope we find in the Faber-Jackson relation of non-BCGs are qualitatively similar to that reported in the black hole mass-velocity dispersion (MBH-σ) correlation. This similarity is consistent with a roughly constant value of MBH/M* over a wide range of early-type galaxies, where M* is the stellar mass.
Finite element analysis of inclined nozzle-plate junctions
International Nuclear Information System (INIS)
Dixit, K.B.; Seth, V.K.; Krishnan, A.; Ramamurthy, T.S.; Dattaguru, B.; Rao, A.K.
1979-01-01
Estimation of stress concentration at nozzle to plate or shell junctions is a significant problem in the stress analysis of nuclear reactors. The topic is a subject matter of extensive investigations and earlier considerable success has been reported on analysis for the cases when the nozzle is perpendicular to the plate or is radial to the shell. Analytical methods for the estimation of stress concentrations for the practical situations when the intersecting nozzle is inclined to the plate or is non-radial to the shell is rather scanty. Specific complications arise in dealing with the junction region when the nozzle with circular cross-section meets the non-circular cut-out on the plate or shell. In this paper a finite element analysis is developed for inclined nozzles and results are presented for nozzle-plate junctions. A method of analysis is developed with a view to achieving simultaneously accuracy of results and simplicity in the choice of elements and their connectivity. The circular nozzle is treated by axisymmetric conical shell elements. The nozzle portion in the region around the junction and the flat plate is dealt with by triangular flat shell elements. Special transition elements are developed for joining the flat shell elements with the axisymmetric elements under non-axisymmetric loading. A substructure method of analysis is adopted which achieves considerable economy in handling the structure and also conveniently combines the different types of elements in the structure. (orig.)
An Experimental Investigation on Inclined Negatively Buoyant Jets
Directory of Open Access Journals (Sweden)
Raed Bashitialshaaer
2012-09-01
Full Text Available An experimental study was performed to investigate the behavior of inclined negatively buoyant jets. Such jets arise when brine is discharged from desalination plants. A turbulent jet with a specific salinity was discharged through a circular nozzle at an angle to the horizontal into a tank with fresh water and the spatial evolution of the jet was recorded. Four different initial jet parameters were changed, namely the nozzle diameter, the initial jet inclination, the jet density and the flow rate. Five geometric quantities describing the jet trajectory that are useful in the design of brine discharge systems were determined. Dimensional analysis demonstrated that the geometric jet quantities studied, if normalized with the jet exit diameter, could be related to the densimetric Froude number. Analysis of the collected data showed that this was the case for a Froude number less than 100, whereas for larger values of the Froude number the scatter in the data increased significantly. As has been observed in some previous investigations, the slope of the best-fit straight line through the data points was a function of the initial jet angle (θ, where the slope increased with θ for the maximum levels (Y_{m} studied, but had a more complex behavior for horizontal distances.
Simplification of rat intubation on inclined metal plate.
Kastl, Sigrid; Kotschenreuther, U; Hille, B; Schmidt, J; Gepp, H; Hohenberger, W
2004-12-01
Small-animal intubation is often necessary during inhalation anesthesia to allow steady-state conditions for large operations and in vivo experiments in all fields of experimental surgery. In rats, placing an orotracheal tube is technically difficult primarily because of the small size of the subject and the lack of equipment specifically designed for this task. We describe a simple rat intubation technique in which the animal is suspended in dorsal recumbency on an inclined metal plate. The animal, anesthetized with ether, is fixed to a 70 degrees-inclined metal plate in a dorsal position by means of a Mersilene ribbon hooked around the upper incisors. This method of positioning the animal is the most important step in the intubation process and further facilitates the technique already described by other authors. A human otoscope was used as a laryngoscope, intubation was performed using the Seldinger technique, and a 14-gauge intravenous catheter served as an endotracheal tube. This inexpensive technique is quickly learned and can be used in any laboratory. Safe and reliable airway management can thus be achieved, permitting in vivo examinations and operations.
Non-dispersive traveling waves in inclined shallow water channels
International Nuclear Information System (INIS)
Didenkulova, Ira; Pelinovsky, Efim
2009-01-01
Existence of traveling waves propagating without internal reflection in inclined water channels of arbitrary slope is demonstrated. It is shown that traveling non-monochromatic waves exist in both linear and nonlinear shallow water theories in the case of a uniformly inclined channel with a parabolic cross-section. The properties of these waves are studied. It is shown that linear traveling waves should have a sign-variable shape. The amplitude of linear traveling waves in a channel satisfies the same Green's law, which is usually derived from the energy flux conservation for smoothly inhomogeneous media. Amplitudes of nonlinear traveling waves deviate from the linear Green's law, and the behavior of positive and negative amplitudes are different. Negative amplitude grows faster than positive amplitude in shallow water. The phase of nonlinear waves (travel time) is described well by the linear WKB approach. It is shown that nonlinear traveling waves of any amplitude always break near the shoreline if the boundary condition of the full absorption is applied.
Dissipative descent: rocking and rolling down an incline
Balmforth, N. J.; Bush, J. W. M.; Vener, D.; Young, W. R.
We consider the dynamics of a hollow cylindrical shell that is filled with viscous fluid and another, nested solid cylinder, and allowed to roll down an inclined plane. A mathematical model is compared to simple experiments. Two types of behaviour are observed experimentally: on steeper slopes, the device accelerates; on shallower inclines, the cylinders rock and roll unsteadily downhill, with a speed that is constant on average. The theory also predicts runaway and unsteady rolling motions. For the rolling solutions, however, the inner cylinder cannot be suspended in the fluid by the motion of the outer cylinder, and instead falls inexorably toward the outer cylinder. Whilst only occurs after an infinite time, the system slows progressively as the gap between the cylinders narrows, owing to heightened viscous dissipation. Such a deceleration is not observed in the experiments, suggesting that some mechanism limits the approach to contact. Coating the surface of the inner cylinder with sandpaper of different grades changes the rolling speed, consistent with the notion that surface roughness is responsible for limiting the acceleration.
Breakdown of air pockets in downwardly inclined sewerage pressure mains.
Lubbers, C L; Clemens, F H L R
2006-01-01
In the Netherlands, wastewater is collected in municipal areas and transported to centralised WWTPs by an extensive system of pressure mains. Over the last decades these pressure mains did not receive much attention in terms of monitoring of performance or maintenance. A recent inventory showed that half of the pressure mains show an increased pressure loss for no directly obvious reason. One of the many causes that account for the reduction of the flow capacity is the occurrence of free gas in the pipeline. During dry weather periods with low flow velocities, gas may accumulate at high points in the system. Once the velocity increases during storm weather flow, the air pockets may be broken down and transported to the end of the system. A research study is started focussing on the description of the gas-water phenomena in wastewater pressure mains with respect to transportation of gas. An experimental facility is constructed for the study of multi-phase flow. This paper describes the preliminary results of experiments on breakdown rates of gas pockets as a function of inclination angle and water flow rate. The results show an increasing breakdown rate with increasing inclination angle.
Directory of Open Access Journals (Sweden)
G. Le
2004-12-01
Full Text Available In this paper, we present in-situ observations of processes occurring at the magnetopause and vicinity, including surface waves, oscillatory magnetospheric field lines, and flux transfer events, and coordinated observations at geosynchronous orbit by the GOES spacecraft, and on the ground by CANOPUS and 210° Magnetic Meridian (210MM magnetometer arrays. On 7 February 2002, during a high-speed solar wind stream, the Polar spacecraft was skimming the magnetopause in a post-noon meridian plane for ~3h. During this interval, it made two short excursions and a few partial crossings into the magnetosheath and observed quasi-periodic cold ion bursts in the region adjacent to the magnetopause current layer. The multiple magnetopause crossings, as well as the velocity of the cold ion bursts, indicate that the magnetopause was oscillating with an ~6-min period. Simultaneous observations of Pc5 waves at geosynchronous orbit by the GOES spacecraft and on the ground by the CANOPUS magnetometer array reveal that these magnetospheric pulsations were forced oscillations of magnetic field lines directly driven by the magnetopause oscillations. The magnetospheric pulsations occurred only in a limited longitudinal region in the post-noon dayside sector, and were not a global phenomenon, as one would expect for global field line resonance. Thus, the magnetopause oscillations at the source were also limited to a localized region spanning ~4h in local time. These observations suggest that it is unlikely that the Kelvin-Helmholz instability and/or fluctuations in the solar wind dynamic pressure were the direct driving mechanisms for the observed boundary oscillations. Instead, the likely mechanism for the localized boundary oscillations was pulsed reconnection at the magnetopause occurring along the X-line extending over the same 4-h region. The Pc5 band pressure fluctuations commonly seen in high-speed solar wind streams may modulate the reconnection rate as
Directory of Open Access Journals (Sweden)
G. Le
2004-12-01
Full Text Available In this paper, we present in-situ observations of processes occurring at the magnetopause and vicinity, including surface waves, oscillatory magnetospheric field lines, and flux transfer events, and coordinated observations at geosynchronous orbit by the GOES spacecraft, and on the ground by CANOPUS and 210° Magnetic Meridian (210MM magnetometer arrays. On 7 February 2002, during a high-speed solar wind stream, the Polar spacecraft was skimming the magnetopause in a post-noon meridian plane for ~3h. During this interval, it made two short excursions and a few partial crossings into the magnetosheath and observed quasi-periodic cold ion bursts in the region adjacent to the magnetopause current layer. The multiple magnetopause crossings, as well as the velocity of the cold ion bursts, indicate that the magnetopause was oscillating with an ~6-min period. Simultaneous observations of Pc5 waves at geosynchronous orbit by the GOES spacecraft and on the ground by the CANOPUS magnetometer array reveal that these magnetospheric pulsations were forced oscillations of magnetic field lines directly driven by the magnetopause oscillations. The magnetospheric pulsations occurred only in a limited longitudinal region in the post-noon dayside sector, and were not a global phenomenon, as one would expect for global field line resonance. Thus, the magnetopause oscillations at the source were also limited to a localized region spanning ~4h in local time. These observations suggest that it is unlikely that the Kelvin-Helmholz instability and/or fluctuations in the solar wind dynamic pressure were the direct driving mechanisms for the observed boundary oscillations. Instead, the likely mechanism for the localized boundary oscillations was pulsed reconnection at the magnetopause occurring along the X-line extending over the same 4-h region. The Pc5 band pressure fluctuations commonly seen in high-speed solar wind streams may modulate the reconnection rate as an
Kaplan, Yonatan; Barak, Yannai; Palmonovich, Ezequiel; Nyska, Meir; Witvrouw, Erik
2014-01-01
I. To evaluate average percentage body weight (APBW) values and weight-bearing distribution percentages (WBDP) between four common sports activities in a referent adult population. II. To suggest clinical implications. Original research study. Lerner Sports Center, Hebrew University, Mount Scopus, Jerusalem, Israel. Seventy-five asymptomatic volunteers, mean age=33.5 (19-72) years SD=15.1, mean weight (kg)=70.7 (43-113) SD=14.1. Four tests were conducted: 1. Overground walking (OGW) over a 20 m distance, 2. Overground jogging (OGJ) over a 20 m distance, 3. Treadmill jogging (TJ) at a constant speed of 8.5 km/h for a 15-second interval and 4. Elliptical exercise (EE) for a 20 second period at a resistance and incline level of 10, and a steady pace within the range of 70-95 steps/min. The Smartstep™ weight-bearing gait analysis system. The APBW value on the entire foot in OGW was 112% (SD=15.57), in OGJ, 201% (SD=31.24, in TJ, 175% (SD=25.48) and in EE, 73% (SD=13.8). Regarding WBDP, the swing phase in OGJ and TJ was significantly longer than the stance phase (p<0.05). OGW resulted in significantly less swing phase compared to OGJ and TJ (p<0.05). EE significantly reduces weight-bearing as compared to other common functional and sporting activities. These findings may assist the rehabilitation team when considering returning individuals back to early activity following certain bony or soft tissue pathologies or lower-limb surgical procedures. This information is also useful from a repetitive loading standpoint (to prevent overuse injury) or for exercise recommendations for those at greater risk for exacerbating chronic joint pathology. Copyright © 2013 Elsevier B.V. All rights reserved.
The Convergence Problems of Eigenfunction Expansions of Elliptic Differential Operators
Ahmedov, Anvarjon
2018-03-01
In the present research we investigate the problems concerning the almost everywhere convergence of multiple Fourier series summed over the elliptic levels in the classes of Liouville. The sufficient conditions for the almost everywhere convergence problems, which are most difficult problems in Harmonic analysis, are obtained. The methods of approximation by multiple Fourier series summed over elliptic curves are applied to obtain suitable estimations for the maximal operator of the spectral decompositions. Obtaining of such estimations involves very complicated calculations which depends on the functional structure of the classes of functions. The main idea on the proving the almost everywhere convergence of the eigenfunction expansions in the interpolation spaces is estimation of the maximal operator of the partial sums in the boundary classes and application of the interpolation Theorem of the family of linear operators. In the present work the maximal operator of the elliptic partial sums are estimated in the interpolation classes of Liouville and the almost everywhere convergence of the multiple Fourier series by elliptic summation methods are established. The considering multiple Fourier series as an eigenfunction expansions of the differential operators helps to translate the functional properties (for example smoothness) of the Liouville classes into Fourier coefficients of the functions which being expanded into such expansions. The sufficient conditions for convergence of the multiple Fourier series of functions from Liouville classes are obtained in terms of the smoothness and dimensions. Such results are highly effective in solving the boundary problems with periodic boundary conditions occurring in the spectral theory of differential operators. The investigations of multiple Fourier series in modern methods of harmonic analysis incorporates the wide use of methods from functional analysis, mathematical physics, modern operator theory and spectral
Random source generating far field with elliptical flat-topped beam profile
International Nuclear Information System (INIS)
Zhang, Yongtao; Cai, Yangjian
2014-01-01
Circular and rectangular multi-Gaussian Schell-model (MGSM) sources which generate far fields with circular and rectangular flat-topped beam profiles were introduced just recently (Sahin and Korotkova 2012 Opt. Lett. 37 2970; Korotkova 2014 Opt. Lett. 39 64). In this paper, a random source named an elliptical MGSM source is introduced. An analytical expression for the propagation factor of an elliptical MGSM beam is derived. Furthermore, an analytical propagation formula for an elliptical MGSM beam passing through a stigmatic ABCD optical system is derived, and its propagation properties in free space are studied. It is interesting to find that an elliptical MGSM source generates a far field with an elliptical flat-topped beam profile, being qualitatively different from that of circular and rectangular MGSM sources. The ellipticity and the flatness of the elliptical flat-topped beam profile in the far field are determined by the initial coherence widths and the beam index, respectively. (paper)
Influences of magma chamber ellipticity on ring fracturing and eruption at collapse calderas
International Nuclear Information System (INIS)
Holohan, Eoghan P; Walsh, John J; Vries, Benjamin van Wyk de; Troll, Valentin R; Walter, Thomas R
2008-01-01
Plan-view ellipticity of a pre-caldera magma reservoir, and its influence on the development of caldera ring fracturing and eruptive behaviour, have not previously been subjected to dedicated evaluation. We experimentally simulated caldera collapse into elliptical magma chambers and found that collapse into highly-elliptical chambers produced a characteristic pattern of ring-fault localization and lateral propagation. Although results are preliminary, the general deformation pattern for elliptical resurgence shows strong similarities to elliptical collapse. Ring faults accommodating uplift again initiate around the chamberos short axis and are reverse, but dip inward. Field and geophysical observations at several elliptical calderas of varying scale (e.g. Long Valley, Katmai, and Rabaul calderas) are consistent with a control from elliptical magma chamber geometry on ring fracturing and eruption, as predicted from our experiments.
Improvement in greenhouse solar drying using inclined north wall reflection
Energy Technology Data Exchange (ETDEWEB)
Sethi, V.P. [Department of Mechanical Engineering, Punjab Agricultural University, Ludhiana 141004, Punjab (India); Arora, Sadhna [Department of Processing and Food Engineering, Punjab Agricultural University, Ludhiana 141004, Punjab (India)
2009-09-15
A conventional greenhouse solar dryer of 6 m{sup 2} x 4 m{sup 2} floor area (east-west orientation) was improved for faster drying using inclined north wall reflection (INWR) under natural as well as forced convection mode. To increase the solar radiation availability onto the product (to be dried) during extreme summer months, a temporary inclined wall covered with aluminized reflector sheet (of 50 {mu}m thickness and reflectance 0.93) was raised inside the greenhouse just in front of the vertical transparent north wall. By doing so, product fully received the reflected beam radiation (which otherwise leaves through the north wall) in addition to the direct total solar radiation available on the horizontal surface during different hours of drying. The increment in total solar radiation input enhanced the drying rate of the product by increasing the inside air and crop temperature of the dryer. Inclination angle of the reflective north wall with vertical ({beta}) was optimized for various selective widths of the tray W (1.5, 2, 2.5 and 3 m) and for different realistic heights of existing vertical north wall (h) at 25 N, 30 N and 35 N latitudes (hot climatic zones). Experimental performance of the improved dryer was tested during the month of May 2008 at Ludhiana (30.56 N) climatic conditions, India by drying bitter gourd (Momordica charantia Linn) slices. Results showed that by using INWR under natural convection mode of drying, greenhouse air and crop temperature increased by 1-6.7 C and 1-4 C, respectively, during different drying hours as compared to, when INWR was not used and saved 13.13% of the total drying time. By using INWR under forced convection mode of drying, greenhouse air and crop temperature increased by 1-4.5 C and 1-3 C, respectively, during different drying hours as compared to, when INWR was not used and saved 16.67% of the total drying time. (author)
Hydraulic shock waves in an inclined chute contraction
Jan, C.-D.; Chang, C.-J.
2009-04-01
A chute contraction is a common structure used in hydraulic engineering for typical reasons such as increase of bottom slope, transition from side channel intakes to tunnel spillways, reduction of chute width due to bridges, transition structures in flood diversion works, among others. One of the significant chute contractions in Taiwan is that used in the Yuanshantzu Flood Diversion Project of Keelung River. The diversion project is designed to divert flood water from upper Keelung River into East Sea with a capasity of 1,310 cubic meters per second for mitigating the flood damage of lower part of Keelung River basin in Northern Taiwan. An inclined chute contraction is used to connect Keelung River and a diversion turnel. The inlet and outlet works of the diversion project is located at Ruifang in the Taipei County of north Taiwan. The diameter of diversion tunnel is 12 meters and the total length of tunnel is 2,484 meters. The diversion project has been completed and successfully executed many times since 2004 to lower the water level of Keelung River in typhoon seasons for avioding flooding problems in the lower part of Keelung River basin. Flow in a chute contraction has complicated flow pattern due to the existence of shock waves in it. A simple and useful calculation procedure for the maximum height and its position of shock waves is essentially needed for the preliminary design stage of a chute contraction. Hydraulic shock waves in an inclined chute contraction were experimentally and numerically investigated in this study with the consideration of the effects of sidewall deflection angle, bottom inclination angle and Froude number of approaching flow. The flow pattern of hydraulic shock waves in a chute contraction was observed. The main issue of designing chute contraction is to estimate the height and position of maximum shock wave for the consideration of freeboards. Achieving this aim, the experimental data are adopted and analyzed for the shock angle
Strength Calculation of Inclined Sections of Reinforced Concrete Elements under Transverse Bending
Filatov, V. B.
2017-11-01
The authors propose a design model to determine the strength of inclined sections of bent reinforced concrete elements without shear reinforcement for the action of transverse force taking into account the aggregate interlock forces in the inclined crack. The calculated dependences to find out the components of forces acting in an inclined section are presented. The calculated dependences are obtained from the consideration of equilibrium conditions of the block over the inclined crack. A comparative analysis of the experimental values of the failure loads of the inclined section and the theoretical values obtained for the proposed dependencies and normative calculation methods is performed. It is shown that the proposed design model makes it possible to take into account the effect the longitudinal reinforcement percentage has on the inclined section strength, the element cross section height without the introduction of empirical coefficients which contributes to an increase in the structural safety of design solutions including the safety of high-strength concrete elements.
Futa, Yuichi; Okazaki, Hiroyuki; Shidama, Yasunari
2013-01-01
In this paper, we introduce our formalization of the definitions and theorems related to an elliptic curve over a finite prime field. The elliptic curve is important in an elliptic curve cryptosystem whose security is based on the computational complexity of the elliptic curve discrete logarithm problem.
Perturbation of sectorial projections of elliptic pseudo-differential operators
DEFF Research Database (Denmark)
Booss-Bavnbek, Bernhelm; Chen, Guoyuan; Lesch, Matthias
2012-01-01
explicitly describe. Our main application deals with a continuous curve of arbitrary first order linear elliptic differential operators over a compact manifold with boundary. Under the additional assumption of the weak inner unique continuation property, we derive the continuity of a related curve......Over a closed manifold, we consider the sectorial projection of an elliptic pseudo-differential operator A of positive order with two rays of minimal growth. We showthat it depends continuously on A when the space of pseudo-differential operators is equipped with a certain topology whichwe...... of Calderón projections and hence of the Cauchy data spaces of the original operator curve. In the Appendix, we describe a topological obstruction against a verbatim use of R. Seeley’s original argument for the complex powers, which was seemingly overlooked in previous studies of the sectorial projection....
Analytical model of impedance in elliptical beam pipes
Pesah, Arthur Chalom
2017-01-01
Beam instabilities are among the main limitations in building higher intensity accelerators. Having a good impedance model for every accelerators is necessary in order to build components that minimize the probability of instabilities caused by the interaction beam-environment and to understand what piece to change in case of intensity increasing. Most of accelerator components have their impedance simulated with finite elements method (using softwares like CST Studio), but simple components such as circular or flat pipes are modeled analytically, with a decreasing computation time and an increasing precision compared to their simulated model. Elliptical beam pipes, while being a simple component present in some accelerators, still misses a good analytical model working for the hole range of velocities and frequencies. In this report, we present a general framework to study the impedance of elliptical pipes analytically. We developed a model for both longitudinal and transverse impedance, first in the case of...
Highly birefringent elliptical core photonic crystal fiber for terahertz application
Sultana, Jakeya; Islam, Md. Saiful; Faisal, Mohammad; Islam, Mohammad Rakibul; Ng, Brian W.-H.; Ebendorff-Heidepriem, Heike; Abbott, Derek
2018-01-01
We present a novel strategy for designing a highly birefringent photonic crystal fiber (PCF) with near zero flattened dispersion properties by applying elliptical air holes in the core area. The elliptical structure of the air holes in the porous-core region introduces asymmetry between x and y polarization modes, which consequently offers ultra-high birefringence. Also the compact geometry of the conventional hexagonal structure in the cladding confines most of the useful power. The optical properties including birefringence, dispersion, confinement loss, effective material loss (EML) and single modeness of the fiber are investigated using a full-vector finite element method. Simulation results show an ultra-high birefringence of 0 . 086 ultra-flattened near zero dispersion of 0 . 53 ± 0 . 07 ps/THz/cm in a broad frequency range. The practical implementation of the proposed fiber is feasible using existing fabrication technology and is applicable to the areas of terahertz sensing and polarization maintaining systems.
Landau-Ginzburg orbifolds, mirror symmetry and the elliptic genus
International Nuclear Information System (INIS)
Berglund, P.; Henningson, M.
1995-01-01
We compute the elliptic genus for arbitrary two-dimensional N=2 Landau-Ginzburg orbifolds. This is used to search for possible mirror pairs of such models. We show that if two Landau-Ginzburg models are conjugate to each other in a certain sense, then to every orbifold of the first theory corresponds an orbifold of the second theory with the same elliptic genus (up to a sign) and with the roles of the chiral and anti-chiral rings interchanged. These orbifolds thus constitute a possible mirror pair. Furthermore, new pairs of conjugate models may be obtained by taking the product of old ones. We also give a sufficient (and possibly necessary) condition for two models to be conjugate, and show that it is satisfied by the mirror pairs proposed by one of the authors and Huebsch. ((orig.))
M-strings, Elliptic Genera and N=4 String Amplitudes
Hohenegger, Stefan
2014-01-01
We study mass-deformed N=2 gauge theories from various points of view. Their partition functions can be computed via three dual approaches: firstly, (p,q)-brane webs in type II string theory using Nekrasov's instanton calculus, secondly, the (refined) topological string using the topological vertex formalism and thirdly, M theory via the elliptic genus of certain M-strings configurations. We argue for a large class of theories that these approaches yield the same gauge theory partition function which we study in detail. To make their modular properties more tangible, we consider a fourth approach by connecting the partition function to the equivariant elliptic genus of R^4 through a (singular) theta-transform. This form appears naturally as a specific class of one-loop scattering amplitudes in type II string theory on T^2, which we calculate explicitly.
M-strings, elliptic genera and N = 4 string amplitudes
International Nuclear Information System (INIS)
Hohenegger, S.; Iqbal, A.
2014-01-01
We study mass-deformed N = 2 gauge theories from various points of view. Their partition functions can be computed via three dual approaches: firstly, (p,q)-brane webs in type II string theory using Nekrasov's instanton calculus, secondly, the (refined) topological string using the topological vertex formalism and thirdly, M theory via the elliptic genus of certain M-strings configurations. We argue for a large class of theories that these approaches yield the same gauge theory partition function which we study in detail. To make their modular properties more tangible, we consider a fourth approach by connecting the partition function to the equivariant elliptic genus of C 2 through a (singular) theta-transform. This form appears naturally as a specific class of one-loop scattering amplitudes in type II string theory on T 2 , which we calculate explicitly. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Nuclear limits on gravitational waves from elliptically deformed pulsars
International Nuclear Information System (INIS)
Krastev, Plamen G.; Li Baoan; Worley, Aaron
2008-01-01
Gravitational radiation is a fundamental prediction of General Relativity. Elliptically deformed pulsars are among the possible sources emitting gravitational waves (GWs) with a strain-amplitude dependent upon the star's quadrupole moment, rotational frequency, and distance from the detector. We show that the gravitational wave strain amplitude h 0 depends strongly on the equation of state of neutron-rich stellar matter. Applying an equation of state with symmetry energy constrained by recent nuclear laboratory data, we set an upper limit on the strain-amplitude of GWs produced by elliptically deformed pulsars. Depending on details of the EOS, for several millisecond pulsars at distances 0.18 kpc to 0.35 kpc from Earth, the maximalh 0 is found to be in the range of ∼[0.4-1.5]x10 -24 . This prediction serves as the first direct nuclear constraint on the gravitational radiation. Its implications are discussed
Elliptic Double-Box Integrals: Massless Scattering Amplitudes beyond Polylogarithms
Bourjaily, Jacob L.; McLeod, Andrew J.; Spradlin, Marcus; von Hippel, Matt; Wilhelm, Matthias
2018-03-01
We derive an analytic representation of the ten-particle, two-loop double-box integral as an elliptic integral over weight-three polylogarithms. To obtain this form, we first derive a fourfold, rational (Feynman-)parametric representation for the integral, expressed directly in terms of dual-conformally invariant cross ratios; from this, the desired form is easily obtained. The essential features of this integral are illustrated by means of a simplified toy model, and we attach the relevant expressions for both integrals in ancillary files. We propose a normalization for such integrals that renders all of their polylogarithmic degenerations pure, and we discuss the need for a new "symbology" of mixed iterated elliptic and polylogarithmic integrals in order to bring them to a more canonical form.
Friction and drag forces on spheres propagating down inclined planes
Tee, Yi Hui; Longmire, Ellen
2017-11-01
When a submerged sphere propagates along an inclined wall at terminal velocity, it experiences gravity, drag, lift, and friction forces. In the related equations of motion, the drag, lift and friction coefficients are unknown. Experiments are conducted to determine the friction and drag coefficients of the sphere over a range of Reynolds numbers. Through high speed imaging, translational and rotational velocities of spheres propagating along a glass plate are determined in liquids with several viscosities. The onset of sliding motion is identified by computing the dimensionless rotation rate of the sphere. Using drag and lift coefficients for Re friction coefficients are calculated for several materials. The friction coefficients are then employed to estimate the drag coefficient for 350 frictional force over this Re range. Supported by NSF (CBET-1510154).
Simulation of Solar Radiation Incident on Horizontal and Inclined Surfaces
Directory of Open Access Journals (Sweden)
MA Basunia
2012-12-01
Full Text Available A computer model was developed to simulate the hourly, daily and monthly average of daily solar radiation on horizontal and inclined surfaces. The measured hourly and daily solar radiation was compared with simulated radiation, and favourable agreement was observed for the measured and predicted values on clear days. The measured and simulated monthly averages of total (diffuse and beam daily solar radiation were compared and a reasonable agreement was observed for a number of stations in Japan. The simulation showed that during the rice harvesting season, September to October, there is a daily average of 14.7 MJ/m2 of solar irradiation on a horizontal surface in Matsuyama, Japan. There is a similar amount of solar radiation on a horizontal surface during the major rice harvesting season, November to December, in Bangladesh. This radiation can be effectively utilized for drying rough rice and other farm crops.
Inclined nanoimprinting lithography-based 3D nanofabrication
Liu, Zhan; Bucknall, David G.; Allen, Mark G.
2011-06-01
We report a 'top-down' 3D nanofabrication approach combining non-conventional inclined nanoimprint lithography (INIL) with reactive ion etching (RIE), contact molding and 3D metal nanotransfer printing (nTP). This integration of processes enables the production and conformal transfer of 3D polymer nanostructures of varying heights to a variety of other materials including a silicon-based substrate, a silicone stamp and a metal gold (Au) thin film. The process demonstrates the potential of reduced fabrication cost and complexity compared to existing methods. Various 3D nanostructures in technologically useful materials have been fabricated, including symmetric and asymmetric nanolines, nanocircles and nanosquares. Such 3D nanostructures have potential applications such as angle-resolved photonic crystals, plasmonic crystals and biomimicking anisotropic surfaces. This integrated INIL-based strategy shows great promise for 3D nanofabrication in the fields of photonics, plasmonics and surface tribology.
Segregation in inclined flows of binary mixtures of spheres
Directory of Open Access Journals (Sweden)
Larcher Michele
2017-01-01
Full Text Available We outline the equations that govern the evolution of segregation of a binary mixture of spheres in flows down inclines. These equations result from the mass and momentum balances of a kinetic theory for dense flows of inelastic spheres that interact through collisions. The theory employed for segregation is appropriate for particles with relatively small differences in size and mass. The flow of the mixture is assumed to reach a fully developed state much more rapidly than does the concentrations of the two species. We illustrate the predictions of the theory for a mixture of spheres of the same diameter but different masses and for spheres of different diameters but nearly the same mass. We show the evolution of the profiles of the concentration fractions of the two types of spheres and the profiles in the final, steady state. The latter compare favourably with those obtained in discrete-element numerical simulations.
Method and apparatus for logging inclined earth boreholes
International Nuclear Information System (INIS)
Youmans, A.H.
1981-01-01
An improved technique is provided for comparing the velocity of an elongated well logging instrument traversing an inclined earth borehole with the playout velocity of the well logging cable at the earth's surface to control both the cable hoist drum rotation and the rate of movement of the subsurface instrument and thus insure cable playout is in equilibrium with the logging instrument movement. Method and apparatus are described for detecting any reduction in movement of the logging instrument through the borehole and for reducing the velocity of the logging cable playout in response thereto by reducing drum rotation. Further, when the velocity of cable playout slows to a preselected value, a monitoring circuit generates control signals which actuate a means of power attached to or integral with the logging instrument which, upon initiation, apply a force to move the logging instrument upward or downward within the borehole
Deformation Analysis of Fixed Bearing Inclined Plane Thrust Bearing
Directory of Open Access Journals (Sweden)
LI Yong--hai
2017-02-01
Full Text Available According to the theory of lubrication，Numerical simulation of the deformation of the thrust bearing of the fixed inclined plane was carried out，by finite element numerical analysis method and using the ANSYS software. The mathematical model of the oil film shape control equations about of the deformation and bearing is established. Analytical result showed that the force caused the tile surface generating concave deformation，and convex deformation increased with the height and the size of the load and bearing;Tile surface temperature generated convex deformation and increased with the height and the size of the temperature of bearing bush;The actual deformation of the tile surface is the superposition of the force and the thermal deformation. This conclusion can provide reference for the design and the application of thrust bearing，to reduce the tile surface，which is not conducive to the carrying capacity of the concave deformation.
Transient flow and heat transfer phenomena in inclined wavy films
Energy Technology Data Exchange (ETDEWEB)
Serifi, Katerina; Bontozoglou, Vasilis [Department of Mechanical and Industrial Engineering, University of Thessaly, 38334, Volos (Greece); Malamataris, Nikolaos A. [Department of Mechanical Engineering, Technological Educational Institution of Western Macedonia, 50100, Kila Kozani (Greece)
2004-08-01
A finite-element numerical scheme is used to study rigorously the flow of an inclined liquid film and the heat transfer from the constant-temperature wall. Regular inlet disturbances are predicted to evolve into periodic or solitary waves depending on the frequency of the forcing. At very low disturbance frequencies parasitic crests appear and the regularity of the wave-train is lost. The effect of a solitary wave-train on heat transfer from the wall is studied, and it is predicted that a stationary temperature distribution develops with periodic flux variation that follows the waves. The thinning of the substrate between successive humps combines with the effect of convection at the crest and tail of the solitary humps to produce heat transfer enhancement significantly above the conduction limit. (authors)
Inclined transpression in the Neka Valley, eastern Alborz, Iran
Nabavi, Seyed Tohid; Díaz-Azpiroz, Manuel; Talbot, Christopher J.
2017-07-01
Three major nappes in the Neka Valley in the eastern Alborz Mountains of Iran allow the Cimmerian to present convergence following the oblique collision between Iran and the southern margin of Eurasia. This work reports the identification of an inclined transpression zone recognized by field investigations and strain analyses of the geometries of formations and detailed mesoscopic structural analyses of multiple faults, folds and a cleavage. The main structures encountered include refolded recumbent asymmetric fold nappes, highly curved fold hinges, in a transpression zone that dips 37° to the NW between boundaries thrusts striking from N050° to N060°. The β angle (the angle between the zone boundary and direction of horizontal far-field shortening) is about 80°. The north-west and south-east boundaries of this zone coincide with the Haji-abad thrust and the Shah-Kuh thrust, respectively. Fold axes generally trend NE-SW and step to both right and left as a result of strike-slip components of fault displacements. Strain analyses using Fry's method on macroscopic ooids and fusulina deformed into oblate ellipsoids indicate that the natural strain varies between 2.1 and 3.14. The estimated angle between the maximum instantaneous strain axis (ISAmax) and the transpression zone boundary ( θ') is between 6° and 20°. The estimated oblique convergence angle ( α), therefore, ranges between 31° and 43°. The average kinematic vorticity number ( W k ) is 0.6, in a zone of sinistral pure shear-dominated inclined triclinic transpression. These results support the applicability of kinematic models of triclinic transpression to natural brittle-ductile shear zones.
Soil-structure interaction on inclined soil layers
International Nuclear Information System (INIS)
Massa, G.; De Stefano, R.
1983-01-01
The case history presented deals with a Category I building having two-thirds of its base founded on a wedge of hard material. This wedge is underlain by an inclined layer of softer material, which also directly supports the remaining one-third of the foundation. The inclined layer is underlain by a third material, possessing large stiffness and extending to great depth. This case is analyzed with the methodology described below: - Determination of the static soil compliances by discretizing the foundation area into a number of strips and taking the soil profile as horizontally layered under each strip. Lumped parameter soil compliances for the whole foundation are obtained by weighting the contributions to stiffness in proportion to the area of each strip. - Definition of the degree of coupling between modes. The soil compliances defined in the previous step include coupling between the vertical and rocking modes and the horizontal and torsional modes through the positioning of the corresponding soil springs. The degree of coupling is checked through a static finite element analysis. - Frequency correction of the static soil compliances taking into account the inhomogeneity of the foundation conditions. The correction is based on obtaining dynamic stiffness coefficients for extreme configurations of the soil profile. - Assessment of the sliding potential of the structure under earthquake loading, considering eccentricities of the dynamic forces and non-uniform friction resistance over the foundation area, accounting for the frictional capacity of the different bearing materials. It is concluded that the simplified technique can provide accurate soil compliances, coupling and frequency corrections for soil-structure interaction on sloping layers, and an appropriate assessment of the sliding potential. (orig./HP)
Stress concentration factors for pressurized elliptic crossbores in blocks
International Nuclear Information System (INIS)
Badr, Elie A.
2006-01-01
Intersecting bore geometries are used in a number of industrial applications including heavy-walled pressure vessels containing oil holes for lubrication, ports for valves and fluid ends of reciprocating pumps. The bore intersection location is a stress concentration point where the maximum hoop stress can be many times the fluid pressure in the bores. Intersecting circular holes in heavy-walled cylinders and rectangular blocks have been extensively investigated. Specifically, stress/pressure concentration curves for intersecting circular bores in rectangular blocks were presented by Sorem et al. [Sorem JR, Shadley JR, Tipton SM. Design curves for maximum stresses in blocks containing pressurized bore intersections. ASME J Mech Des 1990; 113: 427-31.]. However, stress/pressure concentrations due to intersecting elliptic bores have not been broadly investigated. With the availability of computer numerical control (CNC) machinery, bores with elliptic crosssection can be produced with relative ease. In this paper, hoop stress concentration ratios are developed for elliptic crossbores in rectangular blocks. Results indicate that introducing elliptic crossbores, rather than circular ones, significantly reduces the hoop stress concentration factor at the crossbore intersection. Also, the presence of intersecting crossbores has a major effect on the fatigue life of pressure vessels [Badr EA, Sorem JR, Jr Tipton SM. Evaluation of the autofrettage effect on fatigue lives of steel blocks with crossbores using a statistical and a strain-based method. ASTM J Test Eval 2000; 28: 181-8.] and the reduction of hoop stress concentration is expected to enhance the fatigue life of pressure vessels containing crossbores
Elliptical multiple-output quantile regression and convex optimization
Czech Academy of Sciences Publication Activity Database
Hallin, M.; Šiman, Miroslav
2016-01-01
Roč. 109, č. 1 (2016), s. 232-237 ISSN 0167-7152 R&D Projects: GA ČR GA14-07234S Institutional support: RVO:67985556 Keywords : quantile regression * elliptical quantile * multivariate quantile * multiple-output regression Subject RIV: BA - General Mathematics Impact factor: 0.540, year: 2016 http://library.utia.cas.cz/separaty/2016/SI/siman-0458243.pdf
On generalized elliptical quantiles in the nonlinear quantile regression setup
Czech Academy of Sciences Publication Activity Database
Hlubinka, D.; Šiman, Miroslav
2015-01-01
Roč. 24, č. 2 (2015), s. 249-264 ISSN 1133-0686 R&D Projects: GA ČR GA14-07234S Institutional support: RVO:67985556 Keywords : multivariate quantile * elliptical quantile * quantile regression * multivariate statistical inference * portfolio optimization Subject RIV: BA - General Mathematics Impact factor: 1.207, year: 2015 http://library.utia.cas.cz/separaty/2014/SI/siman-0434510.pdf
Certain exponential sums and random walks on elliptic curves
DEFF Research Database (Denmark)
Lange, Tanja; Shparlinski, Igor
2005-01-01
For a given elliptic curve E, we obtain an upper bound on the discrepancy of sets of multiples z_sG where z_s runs through a sequenc Z=(z_1, \\ldots ,z_T) such that k= z_1,..., kz_T is a permutation of z_1,...,z_T, both sequences taken modulo t, for sufficiently many distinct modulo t values of k....
Detection of Buried Inhomogeneous Elliptic Cylinders by a Memetic Algorithm
Caorsi, Salvatore; Massa, Andrea; Pastorino, Matteo; Raffetto, Mirco; Randazzo, Andrea
2003-01-01
The application of a global optimization procedure to the detection of buried inhomogeneities is studied in the present paper. The object inhomogeneities are schematized as multilayer infinite dielectric cylinders with elliptic cross sections. An efficient recursive analytical procedure is used for the forward scattering computation. A functional is constructed in which the field is expressed in series solution of Mathieu functions. Starting by the input scattered data, the iterative minimiza...
On the Rank of Elliptic Curves in Elementary Cubic Extensions
Directory of Open Access Journals (Sweden)
Rintaro Kozuma
2015-01-01
Full Text Available We give a method for explicitly constructing an elementary cubic extension L over which an elliptic curve ED:y2+Dy=x3 (D∈Q∗ has Mordell-Weil rank of at least a given positive integer by finding a close connection between a 3-isogeny of ED and a generic polynomial for cyclic cubic extensions. In our method, the extension degree [L:Q] often becomes small.
Existence of multiple solutions for quasilinear diagonal elliptic systems
Directory of Open Access Journals (Sweden)
Marco Squassina
1999-05-01
Full Text Available Nonsmooth-critical-point theory is applied in proving multiplicity results for the quasilinear symmetric elliptic system $$ -sum_{i,j=1}^{n}D_j(a^{k}_{ij}(x,uD_iu_k+ {1over 2}sum_{i,j=1}^{n}sum_{h=1}^N D_{s_k}a^{h}_{ij}(x,uD_iu_hD_ju_h=g_k(x,u,, $$ for $k=1,..,N$.
A dearth of dark matter in ordinary elliptical galaxies.
Romanowsky, Aaron J; Douglas, Nigel G; Arnaboldi, Magda; Kuijken, Konrad; Merrifield, Michael R; Napolitano, Nicola R; Capaccioli, Massimo; Freeman, Kenneth C
2003-09-19
The kinematics of the outer parts of three intermediate-luminosity elliptical galaxies were studied with the Planetary Nebula Spectrograph. The galaxies' velocity-dispersion profiles were found to decline with the radius, and dynamical modeling of the data indicates the presence of little if any dark matter in these galaxies' halos. This unexpected result conflicts with findings in other galaxy types and poses a challenge to current galaxy formation theories.
Uniqueness of singular solution of semilinear elliptic equation
Indian Academy of Sciences (India)
Nonhomogeneous semilinear elliptic equation; positive solutions; asymptotic behavior; singular ... a removable singular point of a solution of equation (1.1), the existence of the derivatives of the solution depends on the 'blow up' ..... On the other hand, for 0 <ε
On the elliptic flow for nearly symmetric collisions and nuclear ...
Indian Academy of Sciences (India)
The elliptic flow [10] has been proven to be one of the most fruitful probes for extracting the equation of state (EOS) and to ... at a very early stage of the nuclear collision, it is an excellent tool to probe the nuclear equation of state (EOS) under the ... The Plastic Ball group at the Bevalac in. Berkley were the first to quantify the ...
Jacobian elliptic wave solutions in an anharmonic molecular crystal model
International Nuclear Information System (INIS)
Teh, C.G.R.; Lee, B.S.; Koo, W.K.
1997-07-01
Explicit Jacobian elliptic wave solutions are found in the anharmonic molecular crystal model for both the continuum limit and discrete modes. This class of wave solutions include the famous pulse-like and kink-like solitary modes. We would also like to report on the existence of some highly discrete staggered solitary wave modes not found in the continuum limit. (author). 9 refs, 1 fig
Arithmetical Fourier and Limit values of elliptic modular functions
Indian Academy of Sciences (India)
2
In order to remove singularities, Riemann used a well-known device of taking the odd part (3.2) or an alternate sum (3.3) to be stated in §3. In §2 of this note we shall reveal that the limit values of elliptic modular functions in Riemann's fragment II evaluated by the differences of polyloga- rithm function l1(x) of order 1 (cf.
Harassment Origin for Kinematic Substructures in Dwarf Elliptical Galaxies?
Gonzalez-Garcia, A. C.; Aguerri, J. A. L.; Balcells, M.
2005-01-01
[EN]We have run high resolution N-body models simulating the encounter of a dwarf galaxy with a bright elliptical galaxy. The dwarf absorbs orbital angular momentum and shows counter-rotating features in the external regions of the galaxy. To explain the core-envelope kinematic decoupling observed in some dwarf galaxies in high-density environments requires nearly head-on collisions and very little dark matter bound to the dwarf. These kinematic structures appear under rather restrictive cond...
Elliptic equations with measure data in Orlicz spaces
Directory of Open Access Journals (Sweden)
Ge Dong
2008-05-01
Full Text Available This article shows the existence of solutions to the nonlinear elliptic problem $A(u=f$ in Orlicz-Sobolev spaces with a measure valued right-hand side, where $A(u=-mathop{ m div}a(x,u, abla u$ is a Leray-Lions operator defined on a subset of $W_{0}^{1}L_{M}(Omega$, with general $M$.
Petaros, Anja; Garvin, Heather M; Sholts, Sabrina B; Schlager, Stefan; Wärmländer, Sebastian K T S
2017-11-01
The frontal bone is one of the most sexually dimorphic elements of the human skull, due to features such as the glabella, frontal eminences, and frontal inclination. While glabella is frequently evaluated in procedures to estimate sex in unknown human skeletal remains, frontal inclination has received less attention. In this study we present a straightforward, quick, and reproducible method for measuring frontal inclination angles from glabella and supraglabella. Using a sample of 413 human crania from four different populations (U.S. Whites, U.S. Blacks, Portuguese, and Chinese), we test the usefulness of the inclination angles for sex estimation and compare their performance to traditional methods of frontal inclination assessment. Accuracy rates in the range 75-81% were achieved for the U.S. White, U.S. Black, and Portuguese groups. For Chinese the overall accuracy was lower, i.e. 66%. Although some regional variation was observed, a cut-off value of 78.2° for glabellar inclination angles separates female and male crania from all studied populations with good accuracy. As inclination angles measured from glabella captures two sexually dimorphic features (i.e. glabellar prominence and frontal inclination) in a single measure, the observed clear male/female difference is not unexpected. Being continuous variables, inclination angles are suitable for use in statistical methods for sex estimations. Copyright © 2017 Elsevier B.V. All rights reserved.
Elliptic flow of inclusive electrons in Pb-Pb collisions
Energy Technology Data Exchange (ETDEWEB)
Scheid, Sebastian; Bailhache, Raphaelle; Rascanu, Theodor; Appelshaeuser, Harald [Institut fuer Kernphysik, Goethe-Universitaet Frankfurt (Germany); Collaboration: ALICE-Collaboration
2015-07-01
The main purpose of ALICE at the LHC is to investigate the properties of the deconfined state of strongly-interacting matter produced in high-energy heavy-ion collisions. Since heavy quarks, i.e. charm and beauty, are produced on a shorter time scale with respect to the hot fireball, they are suited to probe the interaction dynamics inside the medium. Heavy-flavour hadrons can be measured via their semi-electronic decays at mid-rapidity with ALICE. The heavy-flavour elliptic flow, the second harmonic in the Fourier expansion of the particle azimuthal distribution, is an observable sensitive to the degree of thermalization of charm and beauty quarks in the medium at low p{sub T}, as well as to the path length dependence of the energy loss of heavy quarks at high p{sub T}. In this poster, I will show how the elliptic flow of inclusive electrons is measured with the event-plane method in 20-40% central Pb-Pb collisions at √(s{sub NN})=2.76 TeV. Electrons are identified with the Time-Projection-Chamber and the Time-Of-Flight in the central barrel in the p{sub T} range 1.5-6 GeV/c. The estimation of the remaining hadron contamination will be presented as well as a possible way to subtract this contribution to the elliptic flow.
Parallelization of elliptic solver for solving 1D Boussinesq model
Tarwidi, D.; Adytia, D.
2018-03-01
In this paper, a parallel implementation of an elliptic solver in solving 1D Boussinesq model is presented. Numerical solution of Boussinesq model is obtained by implementing a staggered grid scheme to continuity, momentum, and elliptic equation of Boussinesq model. Tridiagonal system emerging from numerical scheme of elliptic equation is solved by cyclic reduction algorithm. The parallel implementation of cyclic reduction is executed on multicore processors with shared memory architectures using OpenMP. To measure the performance of parallel program, large number of grids is varied from 28 to 214. Two test cases of numerical experiment, i.e. propagation of solitary and standing wave, are proposed to evaluate the parallel program. The numerical results are verified with analytical solution of solitary and standing wave. The best speedup of solitary and standing wave test cases is about 2.07 with 214 of grids and 1.86 with 213 of grids, respectively, which are executed by using 8 threads. Moreover, the best efficiency of parallel program is 76.2% and 73.5% for solitary and standing wave test cases, respectively.
Elliptical Fourier analysis: fundamentals, applications, and value for forensic anthropology.
Caple, Jodi; Byrd, John; Stephan, Carl N
2017-11-01
The numerical description of skeletal morphology enables forensic anthropologists to conduct objective, reproducible, and structured tests, with the added capability of verifying morphoscopic-based analyses. One technique that permits comprehensive quantification of outline shape is elliptical Fourier analysis. This curve fitting technique allows a form's outline to be approximated via the sum of multiple sine and cosine waves, permitting the profile perimeter of an object to be described in a dense (continuous) manner at a user-defined level of precision. A large amount of shape information (the entire perimeter) can thereby be collected in contrast to other methods relying on sparsely located landmarks where information falling in between the landmarks fails to be acquired. First published in 1982, elliptical Fourier analysis employment in forensic anthropology from 2000 onwards reflects a slow uptake despite large computing power that makes its calculations easy to conduct. Without hurdles arising from calculation speed or quantity, the slow uptake may partly reside with the underlying mathematics that on first glance is extensive and potentially intimidating. In this paper, we aim to bridge this gap by pictorially illustrating how elliptical Fourier harmonics work in a simple step-by-step visual fashion to facilitate universal understanding and as geared towards increased use in forensic anthropology. We additionally provide a short review of the method's utility for osteology, a summary of past uses in forensic anthropology, and software options for calculations that largely save the user the trouble of coding customized routines.
Colors of Dwarf Ellipticals from GALEX to WISE
Schombert, James M.
2018-02-01
Multicolor photometry is presented for a sample of 60 dwarf ellipticals (dE’s) selected by morphology. The sample uses data from GALEX, SDSS, and WISE to investigate the colors in the NUV, ugri, and W1 (3.4 μm) filters. We confirm the blueward shift in the color–magnitude relation (CMR) for dE’s, compared to the CMR for bright ellipticals, as seen in previous studies. However, we find that the deviation in color across the UV to near-IR for dE’s is a strong signal of a younger age for dE’s, one that indicates decreasing mean age with lower stellar mass. Lower mass dE’s are found to have mean ages of 4 Gyr and mean [Fe/H] values of ‑1.2. Age and metallicity increase tothe most massive dE’s, with mean ages similar to normal ellipticals (12 Gyr) and their lowest metallicities ([Fe/H] = ‑0.3). Deduced initial star formation rates for dE’s, combined with their current metallicities and central stellar densities, suggest a connection between field low surface brightness (LSB) dwarfs and cluster dE’s, where the cluster environment halts star formation for dE’s, triggering a separate evolutionary path.
Angle-dependent rotation of calcite in elliptically polarized light
Herne, Catherine M.; Cartwright, Natalie A.; Cattani, Matthew T.; Tracy, Lucas A.
2017-08-01
Calcite crystals trapped in an elliptically polarized laser field exhibit intriguing rotational motion. In this paper, we show measurements of the angle-dependent motion, and discuss how the motion of birefringent calcite can be used to develop a reliable and efficient process for determining the polarization ellipticity and orientation of a laser mode. The crystals experience torque in two ways: from the transfer of spin angular momentum (SAM) from the circular polarization component of the light, and from a torque due to the linear polarization component of the light that acts to align the optic axis of the crystal with the polarization axis of the light. These torques alternatingly compete with and amplify each other, creating an oscillating rotational crystal velocity. We model the behavior as a rigid body in an angle-dependent torque. We experimentally demonstrate the dependence of the rotational velocity on the angular orientation of the crystal by placing the crystals in a sample solution in our trapping region, and observing their behavior under different polarization modes. Measurements are made by acquiring information simultaneously from a quadrant photodiode collecting the driving light after it passes through the sample region, and by imaging the crystal motion onto a camera. We finish by illustrating how to use this model to predict the ellipticity of a laser mode from rotational motion of birefringent crystals.
Mechanism of unconventional aerodynamic characteristics of an elliptic airfoil
Directory of Open Access Journals (Sweden)
Sun Wei
2015-06-01
Full Text Available The aerodynamic characteristics of elliptic airfoil are quite different from the case of conventional airfoil for Reynolds number varying from about 104 to 106. In order to reveal the fundamental mechanism, the unsteady flow around a stationary two-dimensional elliptic airfoil with 16% relative thickness has been simulated using unsteady Reynolds-averaged Navier–Stokes equations and the γ-Reθt‾ transition turbulence model at different angles of attack for flow Reynolds number of 5 × 105. The aerodynamic coefficients and the pressure distribution obtained by computation are in good agreement with experimental data, which indicates that the numerical method works well. Through this study, the mechanism of the unconventional aerodynamic characteristics of airfoil is analyzed and discussed based on the computational predictions coupled with the wind tunnel results. It is considered that the boundary layer transition at the leading edge and the unsteady flow separation vortices at the trailing edge are the causes of the case. Furthermore, a valuable insight into the physics of how the flow behavior affects the elliptic airfoil’s aerodynamics is provided.
Eliminating line of sight in elliptic guides using gravitational curving
International Nuclear Information System (INIS)
Kleno, Kaspar H.; Willendrup, Peter K.; Knudsen, Erik; Lefmann, Kim
2011-01-01
Eliminating fast neutrons (λ<0.5A) by removing direct line of sight between the source and the target sample is a well established technique. This can be done with little loss of transmission for a straight neutron guide by horizontal curving. With an elliptic guide shape, however, curving the guide would result in a breakdown of the geometrical focusing mechanism inherent to the elliptical shape, resulting in unwanted reflections and loss of transmission. We present a new and yet untried idea by curving a guide in such a way as to follow the ballistic curve of a neutron in the gravitational field, while still retaining the elliptic shape seen from the accelerated reference frame of the neutron. Analytical calculations and ray-tracing simulations show that this method is useful for cold neutrons at guide lengths in excess of 100 m. We will present some of the latest results for guide optimization relevant for instrument design at the ESS, in particular an off-backscattering spectrometer which utilizes the gravitational curving, for 6.66 A neutrons over a guide length of 300 m.
Zimmer, Bernd; Sino, Hiba
2018-03-19
To analyze common values of bracket torque (Andrews, Roth, MBT, Ricketts) for their validity in achieving incisor inclinations that are considered normal by different cephalometric standards. Using the equations developed in part 1 (eU1 (BOP) = 90° - BT (U1) - TCA (U1) + α 1 - α 2 and eL1 (BOP) = 90° - BT (L1) - TCA (L1) + β 1 - β 2 ) (abbreviations see part 1) and the mean values (± SD) obtained as statistical measures in parts 1 and 2 of the study (α 1 and β 1 [1.7° ± 0.7°], α 2 [3.6° ± 0.3°], β 2 [3.2° ± 0.4°], TCA (U1) [24.6° ± 3.6°] and TCA (L1) [22.9° ± 4.3°]) expected (= theoretically anticipated) values were calculated for upper and lower incisors (U1 and L1) and compared to targeted (= cephalometric norm) values. For U1, there was no overlapping between the ranges of expected and targeted values, as the lowest targeted value of (58.3°; Ricketts) was higher than the highest expected value (56.5°; Andrews) relative to the bisected occlusal plane (BOP). Thus all of these torque systems will aim for flatter inclinations than prescribed by any of the norm values. Depending on target values, the various bracket systems fell short by 1.8-5.5° (Andrews), 6.8-10.5° (Roth), 11.8-15.5° (MBT), or 16.8-20.5° (Ricketts). For L1, there was good agreement of the MBT system with the Ricketts and Björk target values (Δ0.1° and Δ-0.8°, respectively), and both the Roth and Ricketts systems came close to the Bergen target value (both Δ2.3°). Depending on target values, the ranges of deviation for L1 were 6.3-13.2° for Andrews (Class II prescription), 2.3°-9.2° for Roth, -3.7 to -3.2° for MBT, and 2.3-9.2° for Ricketts. Common values of upper incisor bracket torque do not have acceptable validity in achieving normal incisor inclinations. A careful selection of lower bracket torque may provide satisfactory matching with some of the targeted norm values.
Hu, Yun-peng; Chen, Lei; Huang, Jian-yu
2017-08-01
The US Lincoln Laboratory proved that space-based visible (SBV) observation is efficient to observe space objects, especially Geosynchronous Orbit (GEO) objects. After that, SBV observation plays an important role in the space surveillance. In this paper, a novel space-based observation mode is designed to observe all the GEO objects in a relatively short time. A low earth orbit (LEO) satellite, especially a dawn-dusk sun-synchronous orbit satellite, is useful for space-based observation. Thus, the observation mode for GEO objects is based on a dawn-dusk sun-synchronous orbit satellite. It is found that the Pinch Point (PP) regions proposed by the US Lincoln Laboratory are spreading based on the analysis of the evolution principles of GEO objects. As the PP regions becoming more and more widely in the future, many strategies based on it may not be efficient any more. Hence, the key point of the space-based observation strategy design for GEO objects should be emphasized on the whole GEO belt as far as possible. The pseudo-fixed latitude observation mode is proposed in this paper based on the characteristics of GEO belt. Unlike classical space-based observation modes, pseudo-fixed latitude observation mode makes use of the one-dimensional attitude adjustment of the observation satellite. The pseudo-fixed latitude observation mode is more reliable and simple in engineering, compared with the gazing observation mode which needs to adjust the attitude from the two dimensions. It includes two types of attitude adjustment, i.e. daily and continuous attitude adjustment. Therefore, the pseudo-fixed latitude observation mode has two characteristics. In a day, the latitude of the observation region is fixed and the scanning region is about a rectangle, while the latitude of the observation region centre changes each day in a long term based on a daily strategy. The capabilities of a pseudo-fixed latitude observation instrument with a 98° dawn-dusk sun-synchronous orbit are
Elliptic-type soliton combs in optical ring microresonators
Dikandé Bitha, Rodrigues D.; Dikandé, Alain M.
2018-03-01
Soliton crystals are periodic patterns of multispot optical fields formed from either time or space entanglements of equally separated identical high-intensity pulses. These specific nonlinear optical structures have gained interest in recent years with the advent and progress in nonlinear optical fibers and fiber lasers, photonic crystals, wave-guided wave systems, and most recently optical ring microresonator devices. In this work an extensive analysis of characteristic features of soliton crystals is carried out, with an emphasis on their one-to-one correspondence with elliptic solitons. With this purpose in mind, we examine their formation, their stability, and their dynamics in ring-shaped nonlinear optical media within the framework of the Lugiato-Lefever equation. The stability analysis deals with internal modes of the system via a 2 ×2 -matrix Lamé-type eigenvalue problem, the spectrum of which is shown to possess a rich set of bound states consisting of stable zero-fequency modes and unstable decaying as well as growing modes. Turning towards the dynamics of elliptic solitons in ring-shaped fiber resonators with Kerr nonlinearity, we first propose a collective-coordinate approach, based on a Lagrangian formalism suitable for elliptic-soliton solutions to the nonlinear Schrödinger equation with an arbitrary perturbation. Next we derive time evolutions of elliptic-soliton parameters in the specific context of ring-shaped optical fiber resonators, where the optical field evolution is thought to be governed by the Lugiato-Lefever equation. By solving numerically the collective-coordinate equations an analysis of the amplitude, the position, the phase of internal oscillations, the phase velocity, the energy, and phase portraits of the amplitude is carried out and reveals a complex dynamics of the elliptic soliton in ring-shaped optical microresonators. Direct numerical simulations of the Lugiato-Lefever equation are also carried out seeking for stationary
International Nuclear Information System (INIS)
Kim, Gi Dae; Loh, Byoung Gook
2008-01-01
The characteristics of elliptical vibration cutting (EVC) in micro-V grooving in connection with variations of the elliptical cutting locus and the excitation frequency have been investigated with a cutting device consisting of orthogonally connected dual piezoelectric actuators. The elliptical cutting locus was modulated by changing the magnitude and phase difference of harmonic voltages supplied to the piezoelectric actuators, and the maximum excitation frequency used for EVC was 19 kHz. It was found that cyclic breaking of the contact between the tool and the workpiece is a pre-requisite for the merits of the EVC process to be realized. An index termed non-contact index (NCI) involving the vibration amplitude of the elliptical locus, the feed speed and the excitation frequency was defined to determine the existence of cyclic breaking of the contact under a given EVC condition. The surface roughness in the feed direction showed a tendency to increase with the vibration amplitude in the thrust direction and the square of the feed speed, and to decrease with the square of the vibration amplitude in the cutting direction and the square of the excitation frequency. The variation in the cutting resistance was in good agreement with the CR trend curve representing the contact ratio between the tool and the workpiece in EVC; in the EVC process involving breaking of the contact, marked decrease in the cutting force occurred at higher values of CR at which either slight increase in the excitation frequency or in the vibration amplitude results in significant decrease in the cutting force. Reduction in the cutting force preferably contributed to the improvement of machining quality of the micro features by inhibiting burr formation
Chaudhary, A.; Payne, T.; Kinateder, K.; Dao, P.; Beecher, E.; Boone, D.; Elliott, B.
The objective of on-line flagging in this paper is to perform interactive assessment of geosynchronous satellites anomalies such as cross-tagging of a satellites in a cluster, solar panel offset change, etc. This assessment will utilize a Bayesian belief propagation procedure and will include automated update of baseline signature data for the satellite, while accounting for the seasonal changes. Its purpose is to enable an ongoing, automated assessment of satellite behavior through its life cycle using the photometry data collected during the synoptic search performed by a ground or space-based sensor as a part of its metrics mission. The change in the satellite features will be reported along with the probabilities of Type I and Type II errors. The objective of adaptive sequential hypothesis testing in this paper is to define future sensor tasking for the purpose of characterization of fine features of the satellite. The tasking will be designed in order to maximize new information with the least number of photometry data points to be collected during the synoptic search by a ground or space-based sensor. Its calculation is based on the utilization of information entropy techniques. The tasking is defined by considering a sequence of hypotheses in regard to the fine features of the satellite. The optimal observation conditions are then ordered in order to maximize new information about a chosen fine feature. The combined objective of on-line flagging and adaptive sequential hypothesis testing is to progressively discover new information about the features of a geosynchronous satellites by leveraging the regular but sparse cadence of data collection during the synoptic search performed by a ground or space-based sensor. Automated Algorithm to Detect Changes in Geostationary Satellite's Configuration and Cross-Tagging Phan Dao, Air Force Research Laboratory/RVB By characterizing geostationary satellites based on photometry and color photometry, analysts can
Phillips, D.
1980-01-01
Currently on NOAA/NESS's VIRGS system at the World Weather Building star images are being ingested on a daily basis. The image coordinates of the star locations are measured and stored. Subsequently, the information is used to determine the attitude, the misalignment angles between the spin axis and the principal axis of the satellite, and the precession rate and direction. This is done for both the 'East' and 'West' operational geosynchronous satellites. This orientation information is then combined with image measurements of earth based landmarks to determine the orbit of each satellite. The method for determining the orbit is simple. For each landmark measurement one determines a nominal position vector for the satellite by extending a ray from the landmark's position towards the satellite and intersecting the ray with a sphere with center coinciding with the Earth's center and with radius equal to the nominal height for a geosynchronous satellite. The apparent motion of the satellite around the Earth's center is then approximated with a Keplerian model. In turn the variations of the satellite's height, as a function of time found by using this model, are used to redetermine the successive satellite positions by again using the Earth based landmark measurements and intersecting rays from these landmarks with the newly determined spheres. This process is performed iteratively until convergence is achieved. Only three iterations are required.
New inclination changing eclipsing binaries in the Magellanic Clouds
Juryšek, J.; Zasche, P.; Wolf, M.; Vraštil, J.; Vokrouhlický, D.; Skarka, M.; Liška, J.; Janík, J.; Zejda, M.; Kurfürst, P.; Paunzen, E.
2018-01-01
Context. Multiple stellar systems are unique laboratories for astrophysics. Analysis of their orbital dynamics, if well characterized from their observations, may reveal invaluable information about the physical properties of the participating stars. Unfortunately, there are only a few known and well described multiple systems, this is even more so for systems located outside the Milky Way galaxy. A particularly interesting situation occurs when the inner binary in a compact triple system is eclipsing. This is because the stellar interaction, typically resulting in precession of orbital planes, may be observable as a variation of depth of the eclipses on a long timescale. Aims: We aim to present a novel method to determine compact triples using publicly available photometric data from large surveys. Here we apply it to eclipsing binaries (EBs) in Magellanic Clouds from OGLE III database. Our tool consists of identifying the cases where the orbital plane of EB evolves in accord with expectations from the interaction with a third star. Methods: We analyzed light curves (LCs) of 26121 LMC and 6138 SMC EBs with the goal to identify those for which the orbital inclination varies in time. Archival LCs of the selected systems, when complemented by our own observations with Danish 1.54-m telescope, were thoroughly analyzed using the PHOEBE program. This provided physical parameters of components of each system. Time dependence of the EB's inclination was described using the theory of orbital-plane precession. By observing the parameter-dependence of the precession rate, we were able to constrain the third companion mass and its orbital period around EB. Results: We identified 58 candidates of new compact triples in Magellanic Clouds. This is the largest published sample of such systems so far. Eight of them were analyzed thoroughly and physical parameters of inner binary were determined together with an estimation of basic characteristics of the third star. Prior to our
Aerodynamics of wing-assisted incline running in birds.
Tobalske, Bret W; Dial, Kenneth P
2007-05-01
Wing-assisted incline running (WAIR) is a form of locomotion in which a bird flaps its wings to aid its hindlimbs in climbing a slope. WAIR is used for escape in ground birds, and the ontogeny of this behavior in precocial birds has been suggested to represent a model analogous to transitional adaptive states during the evolution of powered avian flight. To begin to reveal the aerodynamics of flap-running, we used digital particle image velocimetry (DPIV) and measured air velocity, vorticity, circulation and added mass in the wake of chukar partridge Alectoris chukar as they engaged in WAIR (incline 65-85 degrees; N=7 birds) and ascending flight (85 degrees, N=2). To estimate lift and impulse, we coupled our DPIV data with three-dimensional wing kinematics from a companion study. The ontogeny of lift production was evaluated using three age classes: baby birds incapable of flight [6-8 days post hatching (d.p.h.)] and volant juveniles (25-28 days) and adults (45+ days). All three age classes of birds, including baby birds with partially emerged, symmetrical wing feathers, generated circulation with their wings and exhibited a wake structure that consisted of discrete vortex rings shed once per downstroke. Impulse of the vortex rings during WAIR was directed 45+/-5 degrees relative to horizontal and 21+/-4 degrees relative to the substrate. Absolute values of circulation in vortex cores and induced velocity increased with increasing age. Normalized circulation was similar among all ages in WAIR but 67% greater in adults during flight compared with flap-running. Estimated lift during WAIR was 6.6% of body weight in babies and between 63 and 86% of body weight in juveniles and adults. During flight, average lift was 110% of body weight. Our results reveal for the first time that lift from the wings, rather than wing inertia or profile drag, is primarily responsible for accelerating the body toward the substrate during WAIR, and that partially developed wings, not yet
Percentiles relative to maxillary permanent canine inclination by age: a radiologic study.
Alessandri Bonetti, Giulio; Zanarini, Matteo; Danesi, Margherita; Parenti, Serena Incerti; Gatto, Maria Rosaria
2009-10-01
Few studies have investigated developmental norms for maxillary permanent canine eruption. In this observational cross-sectional study, we aimed to provide an age-related description of the percentiles relative to canine inclination in a large sample of nonorthodontic patients. Associations between inclination and sector were also analyzed. Canine inclination and sector location were measured on 1020 panoramic radiographs obtained from subjects of white ancestry aged between 8 and 11 years not seeking orthodontic treatment. The total sample comprised 2037 canines. Canine inclination increases between 8 and 9 years and decreases between 9 and 11 years. The greatest value for each percentile is at 9 years. A linear model should be hypothesized for differences in canine inclination between 2 successive ages in correspondence to each percentile. The proportion of sector 2 canines decreases and that of sector 1 increases with age. In the same age group, the inclination generally decreases as the sector decreases. Percentiles by age show the average canine inclination in a certain population. Further studies are required to verify whether percentiles can be a diagnostic aid for determining normal canine inclination at a given age and for quantifying the risk of canine impaction or adjacent root resorption.
How do the substrate reaction forces acting on a gecko's limbs respond to inclines?
Wang, Zhouyi; Dai, Zhendong; Li, Wei; Ji, Aihong; Wang, Wenbao
2015-02-01
Locomotion is an essential character of animals, and excellent moving ability results from the delicate sensing of the substrate reaction forces (SRF) acting on body and modulating the behavior to adapt the motion requirement. The inclined substrates present in habitats pose a number of functional challenges to locomotion. In order to effectively overcome these challenges, climbing geckos execute complex and accurate movements that involve both the front and hind limbs. Few studies have examined gecko's SRF on steeper inclines of greater than 90°. To reveal how the SRFs acting on the front and hind limbs respond to angle incline changes, we obtained detailed measurements of the three-dimensional SRFs acting on the individual limbs of the tokay gecko while it climbed on an inclined angle of 0-180°. The fore-aft forces acting on the front and hind limbs show opposite trends on inverted inclines of greater than 120°, indicating propulsion mechanism changes in response to inclines. When the incline angles change, the forces exerted in the normal and fore-aft directions by gecko's front and hind limbs are reassigned to take full advantage of limbs' different roles in overcoming resistance and in propelling locomotion. This also ensures that weight acts in the angle range between the forces generated by the front and hind limbs. The change in the distribution of SRF with a change in the incline angle is directly linked to the favorable trade-off between locomotive maneuverability and stability.
Variation of the Friction Coefficient for a Cylinder Rolling down an Inclined Board
Yan, Zixiang; Xia, Heming; Lan, Yueheng; Xiao, Jinghua
2018-01-01
A cylinder rolling down an inclined board is a commonly seen and interesting object to study and it is also easy to experiment with and model. Following what has become a popular practice, we use smartphones to measure the angular acceleration of a cylinder rolling down a plane of different inclining angles. The friction force deviates from the…
The effect of surfactants on upward air-water pipe flow at various inclinations
van Nimwegen, A.T.; Portela, L.; Henkes, R.A.W.M.
2016-01-01
In this work, we extend our previous efforts on the effect of surfactants on air-water flow in a vertical pipe by also considering pipe inclinations between 20° (with respect to horizontal) and vertical. For air-water flow, independent of the inclination, there is a regular annular flow at large
Inada, Emi; Saitoh, Issei; Hayasaki, Haruaki; Iwase, Yoko; Kubota, Naoko; Takemoto, Yoshihiko; Yamasaki, Youichi
2012-01-01
The purpose of this study was to clarify the characteristics of permanent and primary tooth-crown inclinations. Landmark points from cephalograms and dental casts of two groups; 23 women (mean 20.3 +/- 3.3 years) and 11 girls (mean 5.2 +/- 0.1 years) were digitized, and the coordinates were integrated and transformed to a standardized plane. The 3-dimensional crown inclinations were projected on the sagittal plane, and the angles between the tooth vectors and the FH plane were calculated. An independent-group t-test was used to test for group differences of each tooth inclination, and correlation coefficients were generated for the inclination angles among the permanent and primary teeth. Most maxillary tooth-crown inclinations showed significant age-related differences, while only the second premolar and primary second molar differed significantly in the mandible. The maxillary molars were parallel to the corresponding mandibular molars and correlated with each other, but the primary molars were not. Significant correlations were found between inclinations of most permanent teeth, but not the primary teeth. Maxillary tooth-crown inclinations change during growth, but tooth-crown inclinations of the mandibular teeth do not.
Generation of an elliptic hollow beam using Mathieu and Bessel functions.
Chakraborty, Rijuparna; Ghosh, Ajay
2006-09-01
A new (to our knowledge) technique for the generation of a propagation-invariant elliptic hollow beam is reported. It avoids the use of the radial Mathieu function and hence is mathematically simpler. Bessel functions with their arguments having elliptic locus are used to generate the mask, which is then recorded using holographic technique. To generate such an elliptic beam, both the angular Mathieu function, i.e., elliptic vortex term, and the expression for the circular vortex are used separately. The resultant mask is illuminated with a plane beam, and the proper filtering of its Fourier transform generates the expected elliptic beam. Results with both vortex terms are satisfactory. It has been observed that even for higher ellipticity the vortices do not separate.
Study on the tool wear of 3-D elliptical vibration cutting
Directory of Open Access Journals (Sweden)
J. Lin
2017-07-01
Full Text Available As always, the rapid wear of tools was one of the key factors limiting the precise turning of difficult-to-machine materials with diamond tool. 3-D elliptical vibration cutting has inherited many advantages of elliptical vibration cutting, such as the intermittent cutting property and friction reverse property. However, studies on the tool wear of three-dimensional elliptical vibration cutting has not been reported yet. The formation principle of 3-D cutting elliptical trajectory was analysed and a prediction model of tool wear was established in the present work. Besides, a self-developed three-dimensional elliptical vibration device was employed to conduct turning experiment. Compared with the proposed model, the experimental results showed a great agreement with the proposed prediction model. This work may provide a reference for the further optimization of the 3-D elliptical vibration cutting parameters.
Space Station Freedom assembly and operation at a 51.6 degree inclination orbit
Troutman, Patrick A.; Brewer, Laura M.; Heck, Michael L.; Kumar, Renjith R.
1993-01-01
This study examines the implications of assembling and operating Space Station Freedom at a 51.6 degree inclination orbit utilizing an enhanced lift Space Shuttle. Freedom assembly is currently baselined at a 220 nautical mile high, 28.5 degree inclination orbit. Some of the reasons for increasing the orbital inclination are (1) increased ground coverage for Earth observations, (2) greater accessibility from Russian and other international launch sites, and (3) increased number of Assured Crew Return Vehicle (ACRV) landing sites. Previous studies have looked at assembling Freedom at a higher inclination using both medium and heavy lift expendable launch vehicles (such as Shuttle-C and Energia). The study assumes that the shuttle is used exclusively for delivering the station to orbit and that it can gain additional payload capability from design changes such as a lighter external tank that somewhat offsets the performance decrease that occurs when the shuttle is launched to a 51.6 degree inclination orbit.
Efficient light trapping in silicon inclined nanohole arrays for photovoltaic applications
Deng, Can; Tan, Xinyu; Jiang, Lihua; Tu, Yiteng; Ye, Mao; Yi, Yasha
2018-01-01
Structural design with high light absorption is the key challenge for thin film solar cells because of its poor absorption. In this paper, the light-trapping performance of silicon inclined nanohole arrays is systematically studied. The finite difference time domain method is used to calculate the optical absorption of different inclination angles in different periods and diameters. The results indicate that the inclined nanoholes with inclination angles between 5° and 45° demonstrate greater light-trapping ability than their counterparts of the vertical nanoholes, and they also show that by choosing the optimal parameters for the inclined nanoholes, a 31.2 mA/cm2 short circuit photocurrent density could be achieved, which is 10.25% higher than the best vertical nanohole system and 105.26% higher than bare silicon with a thickness of 2330 nm. The design principle proposed in this work gives a guideline for choosing reasonable parameters in the application of solar cells.
Experimental Study of Natural Convection Cooling of Vertical Cylinders with Inclined Plate Fins
Directory of Open Access Journals (Sweden)
Jong Bum Lee
2016-05-01
Full Text Available In this paper, natural convection from vertical cylinders with inclined plate fins is investigated experimentally for use in cooling electronic equipment. Extensive experimental investigations are performed for various inclination angles, fin numbers, and base temperatures. From the experimental data, a correlation for estimating the Nusselt number is proposed. The correlation is applicable when the Rayleigh number, inclination angle, and fin number are in the ranges 100,000–600,000, 30°–90°, and 9–36, respectively. Using the correlation, a contour map depicting the thermal resistance as a function of the fin number and fin thickness is presented. Finally, the optimal thermal resistances of cylinders with inclined plate fins and conventional radial plate fins are compared. It is found that that the optimal thermal resistance of the cylinder with inclined fins is 30% lower than that of the cylinder with radial plate fins.
Numerical Analysis of Aerodynamic Characteristics of the Finned Surfaces with Cross-inclined Fins
Directory of Open Access Journals (Sweden)
Lagutin A. E.
2016-12-01
Full Text Available This paper presents results of numerical research and analyses air-side hydraulic performance of tube bundles with cross inclined fins. The numerical simulation of the fin-tube heat exchanger was performed using the Comsol Femlab software. The results of modeling show the influence of fin inclination angle and tube pitch on hydraulic characteristics of finned surfaces. A series of numerical tests were carried out for tube bundles with different inclination angles (γ =900, 850, 650, 60, the fin pitch u=4 mm. The results indicate that tube bundles with cross inclined fins can significantly enhance the average integral value of the air flow rate in channel between fins in comparison with conventional straight fins. Aerodynamic processes on both sides of modificated channel between inclined fins were analyzed. The verification procedures for received results of numerical modeling with experimental data were performed.
Source identity and kernel functions for elliptic Calogero-Sutherland type systems
Langmann, Edwin
2010-01-01
Kernel functions related to quantum many-body systems of Calogero-Sutherland type are discussed, in particular for the elliptic case. The main result is an elliptic generalization of an identity due to Sen that is a source for many such kernel functions. Applications are given, including simple exact eigenfunctions and corresponding eigenvalues of Chalykh-Feigin-Veselov-Sergeev-type deformations of the elliptic Calogero-Sutherland model for special parameter values.
Stability of film boiling on inclined plates and spheres
Aursand, Eskil; Hammer, Morten; Munkejord, Svend Tollak; Müller, Bernhard; Ytrehus, Tor
2017-11-01
In film boiling, a continuous sub-millimeter vapor film forms between a liquid and a heated surface, insulating the two from each other. While quite accurate steady state solutions are readily obtained, the intermediate Reynolds numbers can make transient analysis challenging. The present work is a theoretical study of film boiling instabilities. We study the formation of travelling waves that are a combination of Kelvin-Helmholtz and the Rayleigh-Taylor instabilities. In particular, we study how the nature of this process depends on the Reynolds number, the Bond number, and the inclination of the submerged heated plate. In addition we extend the analysis to the case of a submerged heated sphere. Modelling of the transient dynamics of such films is important for answering practical questions such as how instabilities affect the overall heat transfer, and whether they can lead to complete film boiling collapse (Leidenfrost point). This work has been financed under the MAROFF program. We acknowledge the Research Council of Norway (244076/O80) and The Gas Technology Centre NTNU-SINTEF (GTS) for support.
Articular Eminence Inclination in Medieval and Contemporary Croatian Population
Kranjčić, Josip; Šlaus, Mario; Vodanović, Marin; Peršić, Sanja; Vojvodić, Denis
2016-12-01
Articular eminence inclination (AEI) of the temporomandibular joint leads the mandible in its movements. Therefore, the aim of the present study was to determine AEI values in medieval (MP) and recent (RP) Croatian population. The study was carried out on two groups of specimens: first group with 30 MP human dry skulls, while the other, serving as control group consisted of 137 dry skulls. The AEI was measured on lateral digital skull images as the angle between the best fi t line drawn along the posterior wall of the articular eminence and the Frankfurt horizontal plane. No statistically significant (p>0.05) differences between the left and right side AEI were found between MP skulls and RP skulls. The mean value of MP AEI was 45.5˚, with a range of 20.9˚-64˚. The mean RP AEI value was steeper (61.99˚), with a range of 30˚-94˚. Difference between the mean MP and RP AEI values was statistically significant (pmedieval time, and consequently different masticatory loads and forces.
Evaluation of primary stability of inclined orthodontic mini-implants.
Inaba, Mizuki
2009-09-01
The aim of this study was to investigate the initial stability of mini-implants when placed slanting or perpendicular to the bone surface, and to examine the effects of differences in tractional direction. Titanium mini-implants were inserted into rabbit nasal bones, slanting (60 degrees , 120 degrees ) or perpendicular (90 degrees ) to the bone surface. These implants were then loaded with a force of approximately 2 N, using a NiTi coil spring. The mobilities on the traction and non-traction sides were assessed using the Periotest device immediately after placement and after traction for two weeks. Then, the tissues with the mini-implants were resected, and the contact between the bone and the implant was examined by electron microscopy. There was a tendency for the mobilities of the mini-implants at 60 degrees and 120 degrees to be smaller than those at 90 degrees when measured before and after traction. The bone-implant contact lengths at 60 degrees were significantly longer than those at 90 degrees . There was no significant difference in the bone-implant contact ratio among the different angles. Correlations were evident between implant mobility and contact length or contact ratio. It is concluded that in clinical practice, implants inclined to the bone surface tend to have better primary stability.
Fluorescence intensity dependence on the propagation plane inclination
International Nuclear Information System (INIS)
Fernandez, J.E.; Rubio, Marcelo; Sanchez, H. J.
1987-01-01
An experimental confirmation of the fluorescence intensity behaviour with the inclination of the propagation plane (α angle) was carried out. A special angular sample-holder was developed and set up on our X-ray spectrometer. This sample-holder allows different positions of irradiation of the sample modifying the α angle until the maximum angle (α Μ ) is reached in the limit situation. In this work, this maximum angle was 86 deg and the incidence and take off angles were both 45 deg. The sample-holder and the collimation system were carefully lined up. The fluorescent spectra of three National Bureau of Standards (NBS) standard samples were taken for sixteen different α angle positions. The theoretical scheme for both enhanced fluorescent lines and nonenhanced fluorescent lines was confirmed, i.e. the invariance of the primary intensity with the α angle and the decline of the enhanced fluorescence intensities under the same conditions. This experimental confirmation agrees with theoretical prediction: the vanishing of the secondary fluorescence in the extreme case α = π/2. (Author) [es
Iterated elliptic and hypergeometric integrals for Feynman diagrams
Energy Technology Data Exchange (ETDEWEB)
Ablinger, J.; Radu, C.S.; Schneider, C. [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation (RISC); Bluemlein, J.; Freitas, A. de [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Van Hoeij, M.; Imamoglu, E. [Florida State Univ., Tallahassee, FL (United States). Dept. of Mathematics; Raab, C.G. [Linz Univ. (Austria). Inst. for Algebra
2017-05-15
We calculate 3-loop master integrals for heavy quark correlators and the 3-loop QCD corrections to the ρ-parameter. They obey non-factorizing differential equations of second order with more than three singularities, which cannot be factorized in Mellin-N space either. The solution of the homogeneous equations is possible in terms of convergent close integer power series as {sub 2}F{sub 1} Gauss hypergeometric functions at rational argument. In some cases, integrals of this type can be mapped to complete elliptic integrals at rational argument. This class of functions appears to be the next one arising in the calculation of more complicated Feynman integrals following the harmonic polylogarithms, generalized polylogarithms, cyclotomic harmonic polylogarithms, square-root valued iterated integrals, and combinations thereof, which appear in simpler cases. The inhomogeneous solution of the corresponding differential equations can be given in terms of iterative integrals, where the new innermost letter itself is not an iterative integral. A new class of iterative integrals is introduced containing letters in which (multiple) definite integrals appear as factors. For the elliptic case, we also derive the solution in terms of integrals over modular functions and also modular forms, using q-product and series representations implied by Jacobi's θ{sub i} functions and Dedekind's η-function. The corresponding representations can be traced back to polynomials out of Lambert-Eisenstein series, having representations also as elliptic polylogarithms, a q-factorial 1/η{sup κ}(τ), logarithms and polylogarithms of q and their q-integrals. Due to the specific form of the physical variable x(q) for different processes, different representations do usually appear. Numerical results are also presented.
Iterated elliptic and hypergeometric integrals for Feynman diagrams
International Nuclear Information System (INIS)
Ablinger, J.; Radu, C.S.; Schneider, C.; Bluemlein, J.; Freitas, A. de; Van Hoeij, M.; Imamoglu, E.; Raab, C.G.
2017-05-01
We calculate 3-loop master integrals for heavy quark correlators and the 3-loop QCD corrections to the ρ-parameter. They obey non-factorizing differential equations of second order with more than three singularities, which cannot be factorized in Mellin-N space either. The solution of the homogeneous equations is possible in terms of convergent close integer power series as 2 F 1 Gauss hypergeometric functions at rational argument. In some cases, integrals of this type can be mapped to complete elliptic integrals at rational argument. This class of functions appears to be the next one arising in the calculation of more complicated Feynman integrals following the harmonic polylogarithms, generalized polylogarithms, cyclotomic harmonic polylogarithms, square-root valued iterated integrals, and combinations thereof, which appear in simpler cases. The inhomogeneous solution of the corresponding differential equations can be given in terms of iterative integrals, where the new innermost letter itself is not an iterative integral. A new class of iterative integrals is introduced containing letters in which (multiple) definite integrals appear as factors. For the elliptic case, we also derive the solution in terms of integrals over modular functions and also modular forms, using q-product and series representations implied by Jacobi's θ i functions and Dedekind's η-function. The corresponding representations can be traced back to polynomials out of Lambert-Eisenstein series, having representations also as elliptic polylogarithms, a q-factorial 1/η κ (τ), logarithms and polylogarithms of q and their q-integrals. Due to the specific form of the physical variable x(q) for different processes, different representations do usually appear. Numerical results are also presented.
Incomplete block factorization preconditioning for indefinite elliptic problems
Energy Technology Data Exchange (ETDEWEB)
Guo, Chun-Hua [Univ. of Calgary, Alberta (Canada)
1996-12-31
The application of the finite difference method to approximate the solution of an indefinite elliptic problem produces a linear system whose coefficient matrix is block tridiagonal and symmetric indefinite. Such a linear system can be solved efficiently by a conjugate residual method, particularly when combined with a good preconditioner. We show that specific incomplete block factorization exists for the indefinite matrix if the mesh size is reasonably small. And this factorization can serve as an efficient preconditioner. Some efforts are made to estimate the eigenvalues of the preconditioned matrix. Numerical results are also given.
Transverse magnetic scattering by parallel conducting elliptic cylinders
Sebak, A.
1991-10-01
A boundary value solution to the problem of transverse magnetic multiple scattering by M parallel perfectly conducting elliptic cylinders is presented. The solution is an exact one and based on the separation-of-variables technique and the addition theorem for Mathieu functions. It is expressed in terms of a system of simultaneous linear equations of infinite order, which is then truncated for numerical computations. Representative numerical results for the scattered field by two cylinders are then generated, for some selected sizes and orientations parameters, and presented.
Some new addition formulae for Weierstrass elliptic functions.
Eilbeck, J Chris; England, Matthew; Onishi, Yoshihiro
2014-11-08
We present new addition formulae for the Weierstrass functions associated with a general elliptic curve. We prove the structure of the formulae in n -variables and give the explicit addition formulae for the 2- and 3-variable cases. These new results were inspired by new addition formulae found in the case of an equianharmonic curve, which we can now observe as a specialization of the results here. The new formulae, and the techniques used to find them, also follow the recent work for the generalization of Weierstrass functions to curves of higher genus.
Surfaces immersed in Lie algebras associated with elliptic integrals
International Nuclear Information System (INIS)
Grundland, A M; Post, S
2012-01-01
The objective of this work is to adapt the Fokas–Gel’fand immersion formula to ordinary differential equations written in the Lax representation. The formalism of generalized vector fields and their prolongation structure is employed to establish necessary and sufficient conditions for the existence and integration of immersion functions for surfaces in Lie algebras. As an example, a class of second-order, integrable, ordinary differential equations is considered and the most general solutions for the wavefunctions of the linear spectral problem are found. Several explicit examples of surfaces associated with Jacobian and P-Weierstrass elliptic functions are presented. (paper)
Three dimensional alignment of molecules using elliptically polarized laser fields
DEFF Research Database (Denmark)
Larsen, J.J.; Bjerre, N.; Hald, K.
2000-01-01
We demonstrate, theoretically and experimentally, that an intense, elliptically polarized, nonresonant laser field can simultaneously force all three axes of a molecule to align along given axes fixed in space, thus inhibiting the free rotation in all three Euler angles. Theoretically, the effect...... is illustrated through time dependent quantum mechanical calculations. Experimentally, 3, 4-dibromothiophene molecules are aligned with a nanosecond laser pulse. The alignment is probed by 2D ion imaging of the fragments from a 20 fs laser pulse induced Coulomb explosion....
On state estimation and fusion with elliptical constraints
Energy Technology Data Exchange (ETDEWEB)
Rao, Nageswara S. [ORNL; Liu, Qiang [ORNL
2017-11-01
We consider tracking of a target with elliptical nonlinear constraints on its motion dynamics. The state estimates are generated by sensors and sent over long-haul links to a remote fusion center for fusion. We show that the constraints can be projected onto the known ellipse and hence incorporated into the estimation and fusion process. In particular, two methods based on (i) direct connection to the center, and (ii) shortest distance to the ellipse are discussed. A tracking example is used to illustrate the tracking performance using projection-based methods with various fusers in the lossy long-haul tracking environment.
Continuous dependence of solutions for indefinite semilinear elliptic problems
Directory of Open Access Journals (Sweden)
Elves A. B. Silva
2013-10-01
Full Text Available We consider the superlinear elliptic problem $$ -\\Delta u + m(xu = a(xu^p $$ in a bounded smooth domain under Neumann boundary conditions, where $m \\in L^{\\sigma}(\\Omega$, $\\sigma\\geq N/2$ and $a\\in C(\\overline{\\Omega}$ is a sign changing function. Assuming that the associated first eigenvalue of the operator $-\\Delta + m $ is zero, we use constrained minimization methods to study the existence of a positive solution when $\\widehat{m}$ is a suitable perturbation of m.
Existence and regularity of weak solutions for singular elliptic problems
Directory of Open Access Journals (Sweden)
Brahim Bougherara
2015-11-01
Full Text Available In this article we study the semilinear singular elliptic problem $$\\displaylines{ -\\Delta u = \\frac{p(x}{u^{\\alpha}}\\quad \\text{in } \\Omega \\cr u = 0\\quad \\text{on } \\partial\\Omega,\\quad u>0 \\text{ in } \\Omega, }$$ where $\\Omega$ is a regular bounded domain of $\\mathbb R^{N}$, $\\alpha\\in\\mathbb R$, $p\\in C(\\Omega$ which behaves as $d(x^{-\\beta}$ as $x\\to\\partial\\Omega$ with $d$ the distance function up to the boundary and $0\\leq \\beta 1$.
Preconditioning for Mixed Finite Element Formulations of Elliptic Problems
Wildey, Tim
2013-01-01
In this paper, we discuss a preconditioning technique for mixed finite element discretizations of elliptic equations. The technique is based on a block-diagonal approximation of the mass matrix which maintains the sparsity and positive definiteness of the corresponding Schur complement. This preconditioner arises from the multipoint flux mixed finite element method and is robust with respect to mesh size and is better conditioned for full permeability tensors than a preconditioner based on a diagonal approximation of the mass matrix. © Springer-Verlag Berlin Heidelberg 2013.
Eliminating line of sight in elliptic guides using gravitational curving
DEFF Research Database (Denmark)
Klenø, Kaspar H.; Willendrup, Peter Kjær; Bergbäck Knudsen, Erik
2011-01-01
result in a breakdown of the geometrical focusing mechanism inherent to the elliptical shape, resulting in unwanted reflections and loss of transmission. We present a new and yet untried idea by curving a guide in such a way as to follow the ballistic curve of a neutron in the gravitational field, while...... relevant for instrument design at the ESS, in particular an off-backscattering spectrometer which utilizes the gravitational curving, for 6.66 Å neutrons over a guide length of 300 m....
Development of precision elliptic neutron-focusing supermirror.
Hosobata, Takuya; Yamada, Norifumi L; Hino, Masahiro; Yamagata, Yutaka; Kawai, Toshihide; Yoshinaga, Hisao; Hori, Koichiro; Takeda, Masahiro; Takeda, Shin; Morita, Shin-Ya
2017-08-21
This paper details methods for the precision design and fabrication of neutron-focusing supermirrors, based on electroless nickel plating. We fabricated an elliptic mirror for neutron reflectometry, which is our second mirror improved from the first. The mirror is a 550-millimeter-long segmented mirror assembled using kinematic couplings, with each segment figured by diamond cutting, polished using colloidal silica, and supermirror coated through ion-beam sputtering. The mirror was evaluated with neutron beams, and the reflectivity was found to be 68-90% at a critical angle. The focusing width was 0.17 mm at the full width at half maximum.
Free In-Plane Vibration of Super-Elliptical Plates
Directory of Open Access Journals (Sweden)
Murat Altekin
2011-01-01
Full Text Available Free in-plane vibration of super-elliptical plates of uniform thickness was investigated by the Ritz method. A large variety of plate shapes ranging from an ellipse to a rectangle were examined. Two cases were considered: (1 a completely free, and (2 a point-supported plate. The geometrical boundary conditions were satisfied by the Lagrange multipliers. The results were compared with those of rectangular plates. Basically good agreement was obtained. Matching results were reported, and the discrepancies were highlighted.
Rescattering processes for elliptical polarization: A quantum trajectory analysis
Kopold; Milosevic; Becker
2000-04-24
High-harmonic generation and high-order above-threshold ionization spectra calculated in the strong-field approximation are analyzed in terms of the complex space-time orbits that result from a saddle point analysis of the underlying integrals. For elliptical polarization, the plateaus of the spectra of high-harmonic generation and high-order above-threshold ionization each turn into a staircase of very similar appearance. Each step of the stair can be traced to a particular pair of orbits which are almost identical in both cases.
Energy Technology Data Exchange (ETDEWEB)
Roediger, E. [Hamburger Sternwarte, Universität Hamburg, Gojensbergsweg 112, D-21029 Hamburg (Germany); Kraft, R. P.; Nulsen, P. E. J.; Forman, W. R.; Machacek, M.; Randall, S.; Jones, C. [Harvard/Smithsonian Center for Astrophysics, 60 Garden Street MS-4, Cambridge, MA 02138 (United States); Churazov, E. [MPI für Astrophysik, Karl-Schwarzschild-Str. 1, Garching, D-85741 (Germany); Kokotanekova, R., E-mail: eroediger@hs.uni-hamburg.de [AstroMundus Master Programme, University of Innsbruck, Technikerstr. 25/8, 6020 Innsbruck (Austria)
2015-06-10
Elliptical cluster galaxies are progressively stripped of their atmospheres due to their motion through the intracluster medium (ICM). Deep X-ray observations reveal the fine-structure of the galaxy’s remnant atmosphere and its gas tail and wake. This fine-structure depends on dynamic conditions (galaxy potential, initial gas contents, orbit through the host cluster), orbital stage (early infall, pre-/post-pericenter passage), and ICM plasma properties (thermal conductivity, viscosity, magnetic field structure). We aim to disentangle dynamic and plasma effects in order to use stripped ellipticals as probes of ICM plasma properties. This first paper of a series investigates the hydrodynamics of progressive gas stripping by means of inviscid hydrodynamical simulations. We distinguish a long-lasting initial relaxation phase and a quasi-steady stripping phase. During quasi-steady stripping, the ICM flow around the remnant atmosphere resembles the flow around solid bodies, including a “deadwater” region in the near wake. Gas is stripped from the remnant atmosphere predominantly at its sides via Kelvin–Helmholtz instabilities. The downstream atmosphere is largely shielded from the ICM wind and thus shaped into a tail. Observationally, both this “remnant tail” and the stripped gas in the wake can appear as a “tail”, but only in the wake can galactic gas mix with the ambient ICM. While the qualitative results are generic, the simulations presented here are tailored to the Virgo elliptical galaxy M89 (NGC 4552) for the most direct comparison to observations. Papers II and III of this series describe the effect of viscosity and compare to Chandra and XMM-Newton observations, respectively.
Influence of Cusp Inclination and Type of Retention on Fracture Load of Implant-Supported Crowns.
Rocha, Cibele Oliveira de Melo; Longhini, Diogo; Pereira, Rodrigo de Paula; Arioli, João Neudenir
2017-01-01
There are few informations about the influence of cusp inclination on the fracture strength of implant-supported crowns. The study aimed to evaluate the influence of cusp inclination and retention type on fracture load in implant-supported metal-ceramic single crowns. Sixty crowns were made, classified as cemented and screw-retained with screw access hole (SAH) sealed or not. Standard (33°) and reduced (20°) cusp inclinations were tested for each group (n=10). To support crowns of a mandibular second molar, analogs of external hexagon implants 5.0 were used. The fracture load was measured in a universal testing machine EMIC DL2000 (10 kN load cell; 0.5 mm/min). Two-way ANOVA (retention and cusp inclination) followed by post hoc Tukey's honest significant difference test was used for the statistical analyses (a=0.05). Crowns with reduced cusp inclination exhibited significantly higher fracture load (pcrowns with standard cusp inclination. Cemented crowns showed significantly higher fracture load (pcrowns. The interaction among these factors was not significant (p>0.05) for the fracture load. The sealing of SAH did not influence the fracture load of screw-retained crowns (p>0.05). In conclusion, fracture load of implant-supported metal-ceramic crowns was influenced by retention and cusp inclination, and there was no influence of the sealing of SAH.
Influence of dental chair backrest inclination on the registration of the mandibular position.
Coelho, Mariana Freire; Cavalcanti, Bruno das Neves; Claro Neves, Ana Christina; Jóias, Renata Pilli; Rode, Sigmar de Mello
2015-11-01
Varying the inclination of the dental chair backrest might alter the distribution of occlusal contact points. The purpose of this study was to identify the influence of backrest inclination on the registration of the mandibular position. Ten participants aged between 18 and 30 years with a complete permanent dentition, uncompromised motor function, no tooth mobility, and no temporomandibular disorders were selected. To register interocclusal contacts, an autopolymerizing methylmethacrylate device was adapted to the maxillary anterior teeth and a composite resin increment was added to the mandibular central incisors. Contacts were registered with the following variations in the inclination of the dental chair backrest: 90 degrees, 120 degrees, and 180 degrees. A standardized digital photograph was made of each mark in each backrest position, and the images were superimposed to measure the distances in registration from 90 to 120 and from 90 to 180 degrees. Data were analyzed with the Student paired t test (α=.05). When the chair was inclined from the 90-degree to the 120-degree position, the mandible was repositioned posteriorly by a mean of 0.67 mm, but the difference was not statistically significant. When the chair was inclined from the 90-degree to the 180-degree position, however, the mandible was repositioned posteriorly by a statistically significant mean of 1.41 mm. Mandibular position is influenced by increasing inclination, and this influence was statistically significant at a 180-degree incline. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.
Treating domestic sewage by Integrated Inclined-Plate-Membrane bio-reactor
Song, Li Ming; Wang, Zi; Chen, Lei; Zhong, Min; Dong, Zhan Feng
2017-12-01
Membrane fouling shorten the service life of the membrane and increases aeration rate for membrane surface cleaning. Two membrane bio-reactors, one for working and another for comparing, were set up to evaluate the feasibility of alleviating membrane fouling and improving wastewater treatment efficiency by integrating inclined-plate precipitation and membrane separation. The result show that: (1) Inclined-plate in reactor had a good effect on pollutant removal of membrane bioreactor. The main role of inclined-plate is dividing reactor space and accelerating precipitation. (2) Working reactor have better performance in COD, TN and TP removal, which can attribute to that working reactor (integrated inclined-plate-Membrane bioreactor) takes both advantages of membrane separation and biological treatment. When influent COD, TP and TN concentration is 163-248 mg/L, 2.08-2.81 mg/L and 24.38-30.49 mg/L in working reactor, effluent concentration is 27-35 mg/L, 0.53-0.59 mg/L and 11.28-11.56 mg/L, respectively. (3) Membrane fouling was well alleviated in integrated inclined-plate-Membrane bioreactor, and membrane normal service time is significantly longer than that in comparing reactor, which can attribute to accelerating precipitation of inclined-plate. In summary, integrated inclined-plate-Membrane bioreactor is a promising technology to alleviating membrane fouling and improving wastewater treatment efficiency, having good performance and bright future in application.
Xiang-Gruess, M.; Kroupa, P.
2017-10-01
We study the three-dimensional (3D) evolution of a viscous protoplanetary disc that accretes gas material from a second protoplanetary disc during a close encounter in an embedded star cluster. The aim is to investigate the capability of the mass accretion scenario to generate strongly inclined gaseous discs that could later form misaligned planets. We use smoothed particle hydrodynamics to study mass transfer and disc inclination for passing stars and circumstellar discs with different masses. We explore different orbital configurations to find the parameter space that allows significant disc inclination generation. Thies et al. suggested that significant disc inclination and disc or planetary system shrinkage can generally be produced by the accretion of external gas material with a different angular momentum. We found that this condition can be fulfilled for a large range of gas mass and angular momentum. For all encounters, mass accretion from the secondary disc increases with decreasing mass of the secondary proto-star. Thus, higher disc inclinations can be attained for lower secondary stellar masses. Variations of the secondary disc's orientation relative to the orbital plane can alter the disc evolution significantly. The results taken together show that mass accretion can change the 3D disc orientation significantly resulting in strongly inclined discs. In combination with the gravitational interaction between the two star-disc systems, this scenario is relevant for explaining the formation of highly inclined discs that could later form misaligned planets.
The effect of an inclined landing surface on biomechanical variables during a jumping task.
Hagins, Marshall; Pappas, Evangelos; Kremenic, Ian; Orishimo, Karl F; Rundle, Andrew
2007-11-01
Professional dancers sustain a high number of injuries. Epidemiological studies have suggested that performing on inclined "raked" stages increases the likelihood of injury. However, no studies have examined if biomechanical differences exist between inclined and flat surfaces during functional tasks, such as landing from a jump. Such differences may provide a biomechanical rationale for differences in injury risk for raked stages. Eight professional dancers performed drop jumps from a 40cm platform on flat and inclined surfaces while forces, lower extremity kinematics, and electromyographic activity were collected in a controlled laboratory environment. Dancers landed on the laterally inclined surface with significantly higher knee valgus (4 degrees ), peak knee flexion (9 degrees ), and medial-lateral ground reaction force (GRF) (13.4% body weight) compared to the flat condition. The posterior GRF was higher in the anterior inclined condition compared to the flat condition. In the anterior inclined condition, subjects landed with 1.4 degrees higher knee valgus, 4 degrees more plantarflexion at initial contact, and 3 degrees less dorsiflexion at the end of landing. Biomechanical variables that have been suggested to contribute to injury in previous studies are increased in the inclined floor conditions. These findings provide a preliminary biomechanical rationale for differences in injury rates found in observational studies of raked stages.
Mergers in galaxy groups. I. Structure and properties of elliptical remnants
International Nuclear Information System (INIS)
Taranu, Dan S.; Dubinski, John; Yee, H. K. C.
2013-01-01
We present collisionless simulations of dry mergers in groups of 3 to 25 galaxies to test the hypothesis that elliptical galaxies form at the centers of such groups. Mock observations of the central remnants confirm their similarity to ellipticals, despite having no dissipational component. We vary the profile of the original spiral's bulge and find that ellipticals formed from spirals with exponential bulges have too low Sersic indices. Mergers of spirals with de Vaucouleurs (classical) bulges produce remnants with larger Sersic indices correlated with luminosity, as with Sloan Digital Sky Survey ellipticals. Exponential bulge mergers are better fits to faint ellipticals, whereas classical bulge mergers better match luminous ellipticals. Similarly, luminous ellipticals are better reproduced by remnants undergoing many (>5) mergers, and fainter ellipticals by those with fewer mergers. The remnants follow tight size-luminosity and velocity dispersion-luminosity (Faber-Jackson) relations (<0.12 dex scatter), demonstrating that stochastic merging can produce tight scaling relations if the merging galaxies also follow tight scaling relations. The slopes of the size-luminosity and Faber-Jackson relations are close to observations but slightly shallower in the former case. Both relations' intercepts are offset—remnants are too large but have too low dispersions at fixed luminosity. Some remnants show substantial (v/σ > 0.1) rotational support, although most are slow rotators and few are very fast rotators (v/σ > 0.5). These findings contrast with previous studies concluding that dissipation is necessary to produce ellipticals from binary mergers of spirals. Multiple, mostly minor and dry mergers can produce bright ellipticals, whereas significant dissipation could be required to produce faint, rapidly rotating ellipticals.
Demonstrating H- beam focusing using an elliptical einzel lens
Lawrie, S. R.; Faircloth, D. C.; Letchford, A. P.; Whitehead, M. O.; Wood, T.
2017-08-01
H- ion source research is being performed at the ISIS spallation neutron and muon facility on a dedicated Vessel for Extraction and Source Plasma Analyses (VESPA). The ion extraction and optics system presently being used on ISIS is centered on a combined-function sector dipole magnet. This traps cesium vapor escaping the ion source; mass-separates co-extracted electrons and stripped neutrals, and weak-focusses the highly asymmetric slit-shaped ion beam. Unfortunately the added drift length through the magnet under strong space-charge forces means up to 50% of the beam is collimated on the magnet. The VESPA has shown that the ISIS ion source actually produces 80 mA of beam current at standard settings, but because of magnet collimation only 55 mA is injected into the solenoid Low Energy Beam Transport (LEBT). A new purely electrostatic post-extraction system incorporating an einzel lens with an elliptical aperture is currently under test. This allows much greater flexibility of perveance and phase space matching for injection into the LEBT and Radio Frequency Quadrupole (RFQ). This paper discusses high voltage breakdown mitigation strategies and presents the first results of the novel elliptical transport system. So far, 70 mA of beam has been transported through the new system with a normalized transverse RMS emittance of 0.2 π mm mrad.
Gravitational waves from pulsars in the context of magnetic ellipticity
Energy Technology Data Exchange (ETDEWEB)
Araujo, Jose C.N. de; Coelho, Jaziel G.; Costa, Cesar A. [Instituto Nacional de Pesquisas Espaciais, Divisao de Astrofisica, Sao Jose dos Campos, SP (Brazil)
2017-05-15
In one of our previous articles we have considered the role of a time dependent magnetic ellipticity on the pulsars' braking indices and on the putative gravitational waves these objects can emit. Since only nine of more than 2000 known pulsars have accurately measured braking indices, it is of interest to extend this study to all known pulsars, in particular as regards gravitational wave generation. To do so, as shown in our previous article, we need to know some pulsars' observable quantities such as: periods and their time derivatives, and estimated distances to the Earth. Moreover, we also need to know the pulsars' masses and radii, for which we are adopting current fiducial values. Our results show that the gravitational wave amplitude is at best h ∝ 10{sup -28}. This leads to a pessimistic prospect for the detection of gravitational waves generated by these pulsars, even for Advanced LIGO and Advanced Virgo, and the planned Einstein Telescope, if the ellipticity has a magnetic origin. (orig.)
Monodromy matrix theory of Trojan wave packets on elliptical orbits
Kalinski, Matt
2009-05-01
The possibility of existence of so called Trojan wavepackets on elliptical orbits, nondispersing wave packets once predicted on cirular orbits while the Hydrogen atom is placed in the CP field has been predicted both theoretically [1] and after many years finally confirmed experimentally in recent microwave experiments. They are caused by so called population lock on the resonance with the infinite semi-harmonic but nonlinear spectrum. However no extension of harmonic theory has been given which simply explains the phenomenon as generalized concept of the Paul trap in the atom but for the single electron. Hereby we apply the monodromy matrix theory originally developed by Heller [2] to study such phenomenon. We define the instantaneous Hamiltonian for the electron an the elliptical orbit and surprisingly find out that it needs not to have real eigenvalues for all times of the circular motion while the packed motion is still nondispersing. Numerical simulations using split-operator method are also presented. [1] E. A. Shapiro, M. Kalinski, and J. H. Eberly, ``Non-circular Trojan-like wavepackets: quantum theory and application to quantum control,'' J. Phys. B 33, 3079, (2000); [2] E. J. Heller, ``Bound-State Eigenfunctions of Classically Chaotic Hamiltonian Systems: Scars of Periodic Orbits,'' Phys. Rev. Lett. 53, 1515 (1984).
CTREC: C-arm Tracking and Reconstruction using Elliptic Curves
Chintalapani, Gouthami; Jain, Ameet K.; Burkhardt, David H.; Prince, Jerry L.; Fichtinger, Gabor
2015-01-01
C-arm fluoroscopy is ubiquitous in contemporary surgery, but it lacks the ability to accurately reconstruct three-dimensional information, attributable to the difficulty in obtaining the pose of X-ray images in 3D space. We propose a unified mathematical framework to address the issues of intra-operative pose estimation, correspondence and reconstruction, using simple elliptic curves. In contrast to other fiducial-based tracking methods, our method uses a single ellipse to constrain 5 out of 6 degrees of freedom of C-arm pose, along with randomly distributed unknown points in the imaging volume (either naturally present or induced by randomly placed beads or other markers in the image space) from two images/views to completely recover the C-arm pose. Preliminary phantom experiments indicate an average C-arm tracking accuracy of 0.51° and 0.12° STD. The method appears to be sufficiently accurate and appealing for many clinical applications, since it uses a simple elliptic fiducial coupled with patient information and has very minimal interference with the workspace. PMID:26257988
MINOR MERGERS AND THE SIZE EVOLUTION OF ELLIPTICAL GALAXIES
International Nuclear Information System (INIS)
Naab, Thorsten; Johansson, Peter H.; Ostriker, Jeremiah P.
2009-01-01
Using a high-resolution hydrodynamical cosmological simulation of the formation of a massive spheroidal galaxy we show that elliptical galaxies can be very compact and massive at high redshift in agreement with recent observations. Accretion of stripped infalling stellar material increases the size of the system with time and the central concentration is reduced by dynamical friction of the surviving stellar cores. In a specific case of a spheroidal galaxy with a final stellar mass of 1.5 x 10 11 M sun we find that the effective radius r e increases from 0.7 ± 0.2 kpc at z = 3 to r e = 2.4 ± 0.4 kpc at z = 0 with a concomitant decrease in the effective density of an order of magnitude and a decrease of the central velocity dispersion by approximately 20% over this time interval. A simple argument based on the virial theorem shows that during the accretion of weakly bound material (minor mergers) the radius can increase as the square of the mass in contrast to the usual linear rate of increase for major mergers. By undergoing minor mergers compact high-redshift spheroids can evolve into present-day systems with sizes and concentrations similar to observed local ellipticals. This indicates that minor mergers may be the main driver for the late evolution of sizes and densities of early-type galaxies.
Development of an innovative device for ultrasonic elliptical vibration cutting.
Zhou, Ming; Hu, Linhua
2015-07-01
An innovative ultrasonic elliptical vibration cutting (UEVC) device with 1st resonant mode of longitudinal vibration and 3rd resonant mode of bending vibration was proposed in this paper, which can deliver higher output power compared to previous UEVC devices. Using finite element method (FEM), resonance frequencies of the longitudinal and bending vibrations were tuned to be as close as possible in order to excite these two vibrations using two-phase driving voltages at a single frequency, while wave nodes of the longitudinal and bending vibrations were also adjusted to be as coincident as possible for mounting the device at a single fixed point. Based on the simulation analysis results a prototype device was fabricated, then its vibration characteristics were evaluated by an impedance analyzer and a laser displacement sensor. With two-phase sinusoidal driving voltages both of 480 V(p-p) at an ultrasonic frequency of 20.1 kHz, the developed prototype device achieved an elliptical vibration with a longitudinal amplitude of 8.9 μm and a bending amplitude of 11.3 μm. The performance of the developed UEVC device is assessed by the cutting tests of hardened steel using single crystal diamond tools. Experimental results indicate that compared to ordinary cutting process, the tool wear is reduced significantly by using the proposed device. Copyright © 2015 Elsevier B.V. All rights reserved.