488 research outputs found
Convergence of complex multiplicative cascades
The familiar cascade measures are sequences of random positive measures
obtained on via -adic independent cascades. To generalize them, this
paper allows the random weights invoked in the cascades to take real or complex
values. This yields sequences of random functions whose possible strong or weak
limits are natural candidates for modeling multifractal phenomena. Their
asymptotic behavior is investigated, yielding a sufficient condition for almost
sure uniform convergence to nontrivial statistically self-similar limits. Is
the limit function a monofractal function in multifractal time? General
sufficient conditions are given under which such is the case, as well as
examples for which no natural time change can be used. In most cases when the
sufficient condition for convergence does not hold, we show that either the
limit is 0 or the sequence diverges almost surely. In the later case, a
functional central limit theorem holds, under some conditions. It provides a
natural normalization making the sequence converge in law to a standard
Brownian motion in multifractal time.Comment: Published in at http://dx.doi.org/10.1214/09-AAP665 the Annals of
Applied Probability (http://www.imstat.org/aap/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Unsur Intrinsik dalam Legenda Ulai Bujang Karem Sastra Lisan Dayak Ketungau Sesaek Kabupaten Sekadau
This research aim to analyzing theme, mandate, plot, character, and background in the legend Ulai Bujang Karem Oral Literature Dayak Ketungau Sesaek Sekadau, and describing implementation plan this study into learning Indonesian in the schools. The method used in this study is descriptive method. Based on the analysis of data can be concluded that the legend Ulai Bujang Karem there are theme, mandate, plot, character, and background. This result is expected being Indonesian study materials in the school especially to teach students to analyzing intrinsic element in a story. The learning is guided by the lesson plan that is suitable with the condition and situation with the school learning environment. Keywors: intrinsic element, legend, oral literatur
Recurrence spectrum in smooth dynamical systems
We prove that for conformal expanding maps the return time does have constant
multifractal spectrum. This is the counterpart of the result by Feng and Wu in
the symbolic setting
Bearing Loads in a Vehicular Flywheel Battery
Radial and axial rotor support bearings are critical elements in flywheel batteries for vehicle applications. This paper discusses the quantification of bearing loads required for the development of optimal bearing designs, particularly magnetic bearings. The primary contributors to bearing loads are shown to be vehicle shock, vibration, maneuvering, and gyrodynamics. Emphasis is placed on transit bus applications. Available data for each is presented, including actual measurements made on buses, and a detailed analysis of gyrodynamics.Center for Electromechanic
Investigation of A1g phonons in YBa2Cu3O7 by means of LAPW atomic-force calculations
We report first-principles frozen-phonon calculations for the determination
of the force-free geometry and the dynamical matrix of the five Raman-active
A1g modes in YBa2Cu3O7. To establish the shape of the phonon potentials atomic
forces are calculated within the LAPW method. Two different schemes - the local
density approximation (LDA) and a generalized gradient approximation (GGA) -
are employed for the treatment of electronic exchange and correlation effects.
We find that in the case of LDA the resulting phonon frequencies show a
deviation from experimental values of approximately -10%. Invoking GGA the
frequency values are significantly improved and also the eigenvectors are in
very good agreement with experimental findings.Comment: 15 page
Influence of radial depth of cut on entry conditions and dynamics in face milling application
In this study, acceleration of the workpiece is measured for different radial depths of cut and cutting edge geometries. The influence of the radial depth of cut on the dynamical behavior is evaluated in time and frequency domains. The results for different radial depths of cut and cutting geometries are quantified using the root mean square value of acceleration. The outcome of this research study can be used both for the better cutting data recommendations and improved tool design.У даному дослідженні прискорення оброблюваної деталі вимірювали для різних радіальних глибин різання і геометрії ріжучої кромки фрези. Вплив радіальної глибини різання на динамічну поведінку оцінювали в часових і частотних інтервалах. Отримано кількісні результати для різних радіальних глибин і геометрії різання з використанням середньоквадратичного значення прискорення. Результати цього дослідження можуть бути використані для рекомендацій як покращення процесу різання, так і конструкції інструменту.В данном исследовании ускорение перемещения заготовки измеряли для разных радиальных глубин резания и геометрии режущей кромки фрезы. Влияние радиальной глубины резания на динамическое поведение оценивали во временных и частотных интервалах. Получены количественные результаты для различных радиальных глубин и геометрии резания с использованием среднеквадратичного значения ускорения. Результаты этого исследования могут быть использованы для рекомендаций по улучшению как процесса резания, так конструкции инструмента
Characterization of tool wear when machining Alloy 718 with high pressure cooling using conventional and surface-modified WC–Co tools
Coolant supplied by high pressure into the cutting zone has shown the lower thermal loads on the tool when machining difficult-to-cut materials as the Alloy 718. In this study, we investigate how the combination of high-pressure cooling and tool-surface modifications can lead to further improvements regarding tool life. The general approach is to enhance the coolant-tool interaction by increasing the contact area. Therefore, we machined cooling features into flank and rake faces of commercially available cemented tungsten carbide inserts. In this way, the surface area was increased by ~ 12 %. After the cutting tests, the tools were analyzed by scanning electron microscopy combined with energy-dispersive X-ray spectroscopy. Compared with conventional tools, the tool modifications reduced the flank wear by 45 % for the investigated cutting parameters. Furthermore, we were able to significantly increase the cutting speed and feed rate without failure of the tool. The investigated surface modifications have great potential to enhance the productivity of metal cutting processes
Band-structure trend in hole-doped cuprates and correlation with Tcmax
By calculation and analysis of the bare conduction bands in a large number of
hole-doped high-temperature superconductors, we have identified the energy of
the so-called axial-orbital as the essential, material-dependent parameter. It
is uniquely related to the range of the intra-layer hopping. It controls the Cu
4s-character, influences the perpendicular hopping, and correlates with the
observed Tc at optimal doping. We explain its dependence on chemical
composition and structure, and present a generic tight-binding model.Comment: 5 pages, Latex, 5 eps figure
- …