The Different Periodic Tables of Dmitrii Mendeleev
Laing, Michael
2008-01-01
Between 1869 and 1905 the Russian chemist Dmitrii Mendeleev published several tables with different arrangements of the chemical elements. Four of these are compared with periodic tables by Russian scientists from 1934 and 1969. The difficulties caused by the lanthanoid elements are clearly seen in the table of 1905, which satisfactorily includes…
The Last Element of Mendeleev's Periodic Table
Khazan, Albert
2010-02-01
Despite much achievements of the synthesis for super-heavy elements (10 new elements were obtained during the last 25 years), the experts in Mendeleev's Periodic Table have not answered the most fundamental question: where the Table ends? The calculations produced on the basis of Quantum Mechanics (the physical conditions in micro-scales) do not not answer this question till now. In my study of chemical compounds, I focused onto the physical conditions observed in macro-scales (the subjects of the regular physics and chemistry). Thus, the Law of Hyperboles was discovered in the Periodic Table: given any chemical compound, the contents of any element in it (per 1 gram-atom), including the contents of unknown elements, whose atomic masses can be set up arbitrarily, is described by the equation of a equilateral hyperbola Y=K/X. The tops of all the arcs are distributed along a real axis crossing the line Y=1 in the point of abscissa 411.66, which manifests the actual atomic mass of the last (heaviest) element of the Periodic Table: its location is Period 8, Group 1; its atomic mass is 411.66, its number is 155 (Khazan A. Upper Limit in Mendeleev's Periodic Table --- Element No.155. Svenska fysikarkivet, 2009). )
From the Mendeleev periodic table to particle physics and back to the periodic table
Kibler, M R
2006-01-01
We briefly describe in this paper the passage from Mendeleev's chemistry (1869) to atomic physics (in the 1900's), nuclear physics (in the 1932's) and particle physics (from 1953 to 2006). We show how the consideration of symmetries, largely used in physics since the end of the 1920's, gave rise to a new format of the periodic table in the 1970's. More specifically, this paper is concerned with the application of the group SO(4,2)xSU(2) to the periodic table of chemical elements. It is shown how the Madelung rule of the atomic shell model can be used for setting up a periodic table that can be further rationalized via the group SO(4,2)xSU(2) and some of its subgroups. Qualitative results are obtained from this nonstandard table.
From the Mendeleev periodic table to particle physics and back to the periodic table
Energy Technology Data Exchange (ETDEWEB)
Kibler, Maurice R. [Universite de Lyon, Institut de Physique Nucleaire, Universite Lyon 1 and CNRS/IN2P3, 43 Bd du 11 Novembre 1918, F-69622 Villeurbanne Cedex (France)
2006-11-15
We briefly describe in this paper the passage from Mendeleev's chemistry (1869) to atomic physics (in the 1900's), nuclear physics (in the 1932's) and particle physics (from 1953 to 2006). We show how the consideration of symmetries, largely used in physics since the end of the 1920's, gave rise to a new format of the periodic table in the 1970's. More specifically, this paper is concerned with the application of the group SO(4,2)xSU(2) to the periodic table of chemical elements. It is shown how the Madelung rule of the atomic shell model can be used for setting up a periodic table that can be further rationalized via the group SO(4,2)xSU(2) and some of its subgroups. Qualitative results are obtained from this nonstandard table. (author)
From the Mendeleev periodic table to particle physics and back to the periodic table
Kibler, M. R.
2007-01-01
15 pages; accepted for publication in Foundations of Chemistry (special issue to commemorate the one hundredth anniversary of the death of Mendeleev who died in 1907); version 2: 16 pages; some sentences added; acknowledgment and references added; misprints corrected We briefly describe in this paper the passage from Mendeleev's chemistry (1869) to atomic physics (in the 1900's), nuclear physics (in the 1932's) and particle physics (from 1953 to 2006). We show how the consideration of symm...
Kaji, Masanori
2003-05-01
The favorable and relatively rapid reception of Mendeleev's periodic table of the elements can be attributed, in part at least, to his social connections. These connections were evident in the recently organized Russian Chemical Society. In addition, Mendeleev enjoyed the support of the editorial board of the journal of the German Chemical Society. PMID:12796115
A Method for Calculation of the Upper Limit of Mendeleev's Periodic Table
Khazan, Albert
2010-03-01
40 years ago some scientists claimed that elements heaviest than No.110 are impossible. The technics got much progress in the last years: element 118 has already been registered. Now, the researchers of Joint Inst. for Nuclear Research (Dubna, Russia) claim that the Periodic Table will end with element 150. However they do not provide theoretical proofs to this claim, because the stability limits of electronic shells they calculated by means of Quantum Mechanics do not answer this question in exact. In contrast, I focused onto the contents of chemical compounds along the Table. The used method is as follows. First, it was found that, given any chemical compound, the contents of any element in it (per 1 gram-atom) is described by the equation of a equilateral hyperbola Y=K/X. Then the scaling coefficient was deduced for the hyperbolas, thus the atomic mass of the last (heaviest) element, 411.66, was found as the abscissa of the ultimate point of the arc drawn by the tops of the hyperbolas. With it, the number of the last element, 155, was found as a consequence. See: Khazan A. Upper Limit in Mendeleev's Periodic Table --- Element No.155. Svenska fysikarkivet, 2009.
The slow penetration of the Mendeleev Table in the French school curricula
International Nuclear Information System (INIS)
The great influence of the Berthelot's ideas about the non existence of atoms froze the teaching of chemistry in France for quite a long time. It is only after the Second World War that the study of the atom structure appeared in school curricula. The Mendeleev periodic system that sets the relationship between chemical properties and atom structure entered the curriculum even later in 1978. The article shows that the authors of most school manuals had anticipated the change, for in 1966 all the chemistry manuals of the 6. form had a chapter dedicated to the Mendeleev table while the issue was not yet on the syllabus. (A.C.)
Energy Technology Data Exchange (ETDEWEB)
Vigouroux, C.H. [42300 Roanne (France)
2012-02-15
The great influence of the Berthelot's ideas about the non existence of atoms froze the teaching of chemistry in France for quite a long time. It is only after the Second World War that the study of the atom structure appeared in school curricula. The Mendeleev periodic system that sets the relationship between chemical properties and atom structure entered the curriculum even later in 1978. The article shows that the authors of most school manuals had anticipated the change, for in 1966 all the chemistry manuals of the 6. form had a chapter dedicated to the Mendeleev table while the issue was not yet on the syllabus. (A.C.)
Directory of Open Access Journals (Sweden)
Raos, N.
2011-12-01
Full Text Available The Croatian (Yugoslav Academy of Sciences and Arts was the first academy to elect D. I. Mendeleev as its honorary member (1882, whereas the periodic table of the elements has been taught regularly at the Zagreb University since 1888. The early interest of Croatian chemists in the periodic table should be attributed primarily to their pan-Slavic attitude, particularly as proof that Slavic people were able to produce "their own Newtons" (M. V. Lomonosov and D. I. Mendeleev. Such enthusiastic views, however, did not help in analyzing the contribution of Mendeleev and other scientists to the discovery and development of the periodic table of the elements.
Period Integrals and Tautological Systems
Lian, Bong H; Yau, Shing-Tung
2011-01-01
We study period integrals of CY hypersurfaces in a partial flag variety. We construct a holonomic system of differential equations which govern the period integrals. By means of representation theory, a set of generators of the system can be described explicitly. The results are also generalized to CY complete intersections. The construction of these new systems of differential equations have lead us to the notion of a tautological system.
Periodic solutions of periodically harvested lotka-volterra systems
Hausrath, Alan R.; Manasevich, Raul F.
2012-01-01
We study a Lotka-Volterra system with periodic harvesting, find sufficient conditions for the existence of periodic solutions with the same period, and, under certain conditions, count the number of such periodic solutions.
Soliton Management in Periodic Systems
Malomed, Boris A
2006-01-01
During the past ten years, there has been intensive development in theoretical and experimental research of solitons in periodic media. This book provides a unique and informative account of the state-of-the-art in the field. The volume opens with a review of the existence of robust solitary pulses in systems built as a periodic concatenation of very different elements. Among the most famous examples of this type of systems are the dispersion management in fiber-optic telecommunication links, and (more recently) photonic crystals. A number of other systems belonging to the same broad class of spatially periodic strongly inhomogeneous media (such as the split-step and tandem models) have recently been identified in nonlinear optics, and transmission of solitary pulses in them was investigated in detail. Similar soliton dynamics occurs in temporal-domain counterparts of such systems, where they are subject to strong time-periodic modulation (for instance, the Feshbach-resonance management in Bose-Einstein conde...
A Periodic Lotka-Volterra System
Tsvetkov, D.
1996-01-01
In this paper periodic time-dependent Lotka-Volterra systems are considered. It is shown that such a system has positive periodic solutions. It is done without constructive conditions over the period and the parameters.
Fractional-period excitations in continuum periodic systems
International Nuclear Information System (INIS)
We investigate the generation of fractional-period states in continuum periodic systems. As an example, we consider a Bose-Einstein condensate confined in an optical-lattice potential. We show that when the potential is turned on nonadiabatically, the system explores a number of transient states whose periodicity is a fraction of that of the lattice. We illustrate the origin of fractional-period states analytically by treating them as resonant states of a parametrically forced Duffing oscillator and discuss their transient nature and potential observability
Positive periodic solutions of delayed periodic Lotka-Volterra systems
Energy Technology Data Exchange (ETDEWEB)
Lin Wei [Laboratory of Nonlinear Mathematics Science, Institute of Mathematics, Fudan University, Shanghai 200433 (China)]. E-mail: weilin@fudan.edu.cn; Chen Tianping [Laboratory of Nonlinear Mathematics Science, Institute of Mathematics, Fudan University, Shanghai 200433 (China)]. E-mail: tchen@fudan.edu.cn
2005-01-17
In this Letter, for a general class of delayed periodic Lotka-Volterra systems, we prove some new results on the existence of positive periodic solutions by Schauder's fixed point theorem. The global asymptotical stability of positive periodic solutions is discussed further, and conditions for exponential convergence are given. The conditions we obtained are weaker than the previously known ones and can be easily reduced to several special cases.
Positive periodic solutions of delayed periodic Lotka-Volterra systems
Lin, Wei; Chen, Tianping
2005-01-01
In this Letter, for a general class of delayed periodic Lotka-Volterra systems, we prove some new results on the existence of positive periodic solutions by Schauder's fixed point theorem. The global asymptotical stability of positive periodic solutions is discussed further, and conditions for exponential convergence are given. The conditions we obtained are weaker than the previously known ones and can be easily reduced to several special cases.
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
The relationship between the types of binary alloy phase diagrams of Vlll and IB group elements and the Men deleev numbers was discussed for the first time using the Vlll and IB group elements as solvent metals (A) and the other elements as solute metals (B), basesd on their alloy phase diagram types. The Mendeleev numbers of the solvent metals and the solute metals were expressed as Ma and MB, respectively. A two-dimension map of MdMB was drawn. It is indicated that there is an oblique line in the map, which divides the binary alloy phase diagram types of solvent metals into two symmetry parts, the phase diagram types of the other elements with solvent metals located at the above or down of the line respectively, while on the line, AM= 0. The phase diagrams between the solvent metals basically are simple systems, mainly belong to the types of continues solid solution and the peritectic (about 40% for each type). The solvent metals can be divided into three groups: Co, Ir, Rh, Ni, Pt, and Pd as the first group; Ag, Au, and Cu as the second group;and Fe, Os, and Ru as the third group. The characteristics of the phase diagrams formed between the elements in each group were discussed. About 80% phase diagrams belong to complex systems and less than 20% belong to the simple systems. The regular variation of the chemical scale, the metallic radii of the atoms, the number of valence electrons, and the first ionization energy with the Mendeleev numbers and the crystal structure were introduced as well.
Gabor systems on discrete periodic sets
Institute of Scientific and Technical Information of China (English)
LI YunZhang; LIAN QiaoFang
2009-01-01
Due to its good potential for digital signal processing,discrete Gabor analysis has inter ested some mathematicians.This paper addresses Gabor systems on discrete periodic sets,which can model signals to appear periodically but intermittently.Complete Gabor systems and Gabor frames on discrete periodic sets are characterized; a sufficient and necessary condition on what periodic sets admit complete Gabor systems is obtained; this condition is also proved to be sufficient and necessary for the existence of sets E such that the Gabor systems generated by XE are tight frames on these periodic sets; our proof is constructive,and all tight frames of the above form with a special frame bound can be obtained by our method; periodic sets admitting Gabor Riesz bases are characterized;some examples are also provided to illustrate the general theory.
Gabor systems on discrete periodic sets
Institute of Scientific and Technical Information of China (English)
2009-01-01
Due to its good potential for digital signal processing, discrete Gabor analysis has interested some mathematicians. This paper addresses Gabor systems on discrete periodic sets, which can model signals to appear periodically but intermittently. Complete Gabor systems and Gabor frames on discrete periodic sets are characterized; a sufficient and necessary condition on what periodic sets admit complete Gabor systems is obtained; this condition is also proved to be sufficient and necessary for the existence of sets E such that the Gabor systems generated by χE are tight frames on these periodic sets; our proof is constructive, and all tight frames of the above form with a special frame bound can be obtained by our method; periodic sets admitting Gabor Riesz bases are characterized; some examples are also provided to illustrate the general theory.
Attractors of the periodically forced Rayleigh system
Directory of Open Access Journals (Sweden)
Petre Bazavan
2011-07-01
Full Text Available The autonomous second order nonlinear ordinary differential equation(ODE introduced in 1883 by Lord Rayleigh, is the equation whichappears to be the closest to the ODE of the harmonic oscillator withdumping.In this paper we present a numerical study of the periodic andchaotic attractors in the dynamical system associated with the generalized Rayleigh equation. Transition between periodic and quasiperiodic motion is also studied. Numerical results describe the system dynamics changes (in particular bifurcations, when the forcing frequency is varied and thus, periodic, quasiperiodic or chaotic behaviour regions are predicted.
Mistake of Having Students Be Mendeleev Just for a Day
Criswell, Brett
2007-01-01
The study describes a new methodology and learning cycle, which will give a better understanding of the periodic table to the students. The students following the cycle have now started focusing more on the chemical instead of physical properties when developing their schemes.
Dynamics of Coulombic and gravitational periodic systems
Kumar, Pankaj; Miller, Bruce N.
2016-04-01
We study the dynamics and the phase-space structures of Coulombic and self-gravitating versions of the classical one-dimensional three-body system with periodic boundary conditions. We demonstrate that such a three-body system may be reduced isomorphically to a spatially periodic system of a single particle experiencing a two-dimensional potential on a rhombic plane. For the case of both Coulombic and gravitational versions, exact expressions of the Hamiltonian have been derived in rhombic coordinates. We simulate the phase-space evolution through an event-driven algorithm that utilizes analytic solutions to the equations of motion. The simulation results show that the motion exhibits chaotic, quasiperiodic, and periodic behaviors in segmented regions of the phase space. While there is no evidence of global chaos in either the Coulombic or the gravitational system, the former exhibits a transition from a completely nonchaotic phase space at low energies to a mixed behavior. Gradual yet striking transitions from mild to intense chaos are indicated with changing energy, a behavior that differentiates the spatially periodic systems studied in this Rapid Communication from the well-understood free-boundary versions of the three-body problem. Our treatment of the three-body systems opens avenues for analysis of the dynamical properties exhibited by spatially periodic versions of various classes of systems studied in plasma and gravitational physics as well as in cosmology.
The nature of the acoustic basement on Mendeleev and northwestern Alpha ridges, Arctic Ocean
Bruvoll, Vibeke; Kristoffersen, Yngve; Coakley, Bernard J.; Hopper, John R.; Planke, Sverre; Kandilarov, Aleksandre
2012-01-01
The Alpha-Mendeleev ridge complex, over 1500 km long and 250-400 km wide, is the largest submarine structure in the Arctic Ocean basin. Its origin is unknown, but often inferred to represent a large igneous province where domains of continental crust may also be a possibility. We investigate the basement geology of part of this large scale feature using 1100 km of multichannel seismic reflection data, sonobuoy recordings and marine gravity data acquired in 2005 from USCG icebreaker Healy. The sonobuoy results show top and intra-acoustic basement velocities in the range of 2.3-4.0 km/s and the seismic reflection attributes define three main acoustic facies: 1) continuous high amplitude reflections often with abrupt breaks, 3) weak wedge geometry and 3) segmented, disrupted to chaotic reflections. The acoustic characteristics and seismic velocities compare more closely with basement on Ontong Java Plateau than normal ocean crust or wedges of seaward dipping reflections at volcanic margins. The acoustic facies are interpreted to represent basalt flows and sills capping voluminous tuff deposits and possible sediments. At least two volcanic centres are identified. The upper volcanic carapace on the surveyed part of Mendeleev and northwestern Alpha ridges was emplaced during a brief igneous episode no later than Campanian (80 Ma) and most likely part of wider Late Cretaceous circum Arctic volcanism. The horst and graben morphology on Mendeleev Ridge is largely a result of post-emplacement faulting where a number of the major extensional faults remained active until a late Miocene intrusive event.
Periodic orbits in hyperchaotic Chen systems
Directory of Open Access Journals (Sweden)
Susanna Maza
2015-08-01
Full Text Available In this work, we show a zero-Hopf bifurcation in a Hyperchaotic Chen system. Using averaging theory, we prove the existence of two periodic orbits bifurcating from the zero-Hopf equilibria located at the origin of the Hyperchaotic Chen system.
Subcortical cytoskeleton periodicity throughout the nervous system.
D'Este, Elisa; Kamin, Dirk; Velte, Caroline; Göttfert, Fabian; Simons, Mikael; Hell, Stefan W
2016-03-07
Superresolution fluorescence microscopy recently revealed a ~190 nm periodic cytoskeleton lattice consisting of actin, spectrin, and other proteins underneath the membrane of cultured hippocampal neurons. Whether the periodic cytoskeleton lattice is a structural feature of all neurons and how it is modified when axons are ensheathed by myelin forming glial cells is not known. Here, STED nanoscopy is used to demonstrate that this structure is a commonplace of virtually all neuron types in vitro. To check how the subcortical meshwork is modified during myelination, we studied sciatic nerve fibers from adult mice. Periodicity of both actin and spectrin was uncovered at the internodes, indicating no substantial differences between unmyelinated and myelinated axons. Remarkably, the actin/spectrin pattern was also detected in glial cells such as cultured oligodendrocyte precursor cells. Altogether our work shows that the periodic subcortical cytoskeletal meshwork is a fundamental characteristic of cells in the nervous system and is not a distinctive feature of neurons, as previously thought.
Subcortical cytoskeleton periodicity throughout the nervous system.
D'Este, Elisa; Kamin, Dirk; Velte, Caroline; Göttfert, Fabian; Simons, Mikael; Hell, Stefan W
2016-01-01
Superresolution fluorescence microscopy recently revealed a ~190 nm periodic cytoskeleton lattice consisting of actin, spectrin, and other proteins underneath the membrane of cultured hippocampal neurons. Whether the periodic cytoskeleton lattice is a structural feature of all neurons and how it is modified when axons are ensheathed by myelin forming glial cells is not known. Here, STED nanoscopy is used to demonstrate that this structure is a commonplace of virtually all neuron types in vitro. To check how the subcortical meshwork is modified during myelination, we studied sciatic nerve fibers from adult mice. Periodicity of both actin and spectrin was uncovered at the internodes, indicating no substantial differences between unmyelinated and myelinated axons. Remarkably, the actin/spectrin pattern was also detected in glial cells such as cultured oligodendrocyte precursor cells. Altogether our work shows that the periodic subcortical cytoskeletal meshwork is a fundamental characteristic of cells in the nervous system and is not a distinctive feature of neurons, as previously thought. PMID:26947559
PERIODIC SOLUTIONS OF ASYMPTOTICALLY LINEAR HAMILTONIAN SYSTEMS
Institute of Scientific and Technical Information of China (English)
FEIGUIHUA; QIUQINGJIU
1997-01-01
The authors establish the existence of nontrival periodic solutions of the asymptotically linear Hamiltomian systems in the general case that the asymptotic matrix may be degenerate and time-dependent.This is done by using the critical point theory,Galerkin approximation procedure and the Maslov-type index theory introduced and generalized by Conley,Zehnder and Long.
The long period seismic system of Gauribidanur
International Nuclear Information System (INIS)
This report describes the seismic long-period data acquisition system at Gauribidanur. The field electronics was designed to achieve a configuration of improved stability and dynamic range in the pass band of 0.025-0.1 hz. Some typical records obtained by the system are shown. Surface wave magnitudes estimated at the Gauribidanur Seismic Array are found to be in general agreement with those of international estimates. (author)
Deep structure of crust and the upper mantle of the Mendeleev Rise on the Arktic-2012 DSS profile
DEFF Research Database (Denmark)
Kashubin, Sergey; Petrov, Oleg; Artemieva, Irina;
2016-01-01
During highlatitude combined geological and geophysical expedition “Arctic-2012”, deep seismic sounding (DSS) with ocean bottom seismometers were carried out in the Arctic Ocean along the line 740 km long, crossing the Mendeleev Rise at about 77° N. Crustal and upper mantle Vpvelocity and Vp...
Competing periodicities in a convecting system
International Nuclear Information System (INIS)
In this study, a variety of novel phases was discovered in a nonequilibrium system that has undergone an instability. These phases are closely related to commensurate and incommensurate states found in many solid state materials. It is widely recognized that this behavior is a general phenomenon resulting from the presence of two competing lengths. To study the effects of competing periodicities in a nonequilibrium system, a convective flow was subjected to spatially periodic forcing with a period different from the naturally chosen one. For reasons of experimental convenience, an electrohydrodynamic instability in a thin layer of nematic liquid crystal was utilized. Samples containing several hundred rolls are easily obtained and visualized; thus, phenomena occurring in an effectively infinite layer could be studied. The periodic forcing is imposed by using a specially designed interdigitated electrode. The author found, both commensurate and incommensurate states of several distinct types, and used digital image analysis to study their structure. In a separate investigation, the first direct observation was made of the Eckhaus instability, a phenomenon characterized by long wavelength modulations of a primary roll structure
Periodic inspections of the primary system
International Nuclear Information System (INIS)
An impression is given of the inspection techniques, preparations and background for periodic examinations of the primary system of the Dodewaard Nuclear Reactor over the past 10 years. Unfortunately reliable integral inspection techniques to enable 'listening-in' to developing faults, are not yet available. Until they are, inspections will continue to be executed from a distance using different continuous methods, often under water and with a shortage of space and in the presence of ionising radiations. (C.F.)
Periodic Solutions for Highly Nonlinear Oscillation Systems
DEFF Research Database (Denmark)
Ghadimi, M; Barari, Amin; Kaliji, H.D;
2012-01-01
In this paper, Frequency-Amplitude Formulation is used to analyze the periodic behavior of tapered beam as well as two complex nonlinear systems. Many engineering structures, such as offshore foundations, oil platform supports, tower structures and moving arms, are modeled as tapered beams. The r....... The results obtained are compared with Variational Iteration Method (VIM) and other analytical methods as well as time marching solution. The results given show the effectiveness and accuracy of the proposed techniques....
Periodicity and map for discovery of new ionic liquids
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
There is virtually no limit in the number of ionic liquids. How to select proper ones or discover new ones with desirable properties in such a large pool of ionic liquids? It has become a bottleneck in the researches and applications of ionic liquids. Mendeleev's periodic law states that the properties of the elements vary periodically. Whether the similar regularity exists among ionic or molecular fragments of compounds is an interesting topic. In this work, we attempted to establish a periodicity and draw a "map" of ionic liquids for providing definite guidance to discover, design, and select the proper ionic liquids rather than trial-and-error. If a complete regularity of the system of ionic liquids can be finally established in the future, we are near an epoch in understanding the existing differences and the reasons for the similarity of the ions or molecular fragments.
Homogenization of Periodic Systems with Large Potentials
Allaire, Grégoire; Capdeboscq, Yves; Piatnitski, Andrey; Siess, Vincent; Vanninathan, M.
2004-11-01
We consider the homogenization of a system of second-order equations with a large potential in a periodic medium. Denoting by ɛ the period, the potential is scaled as ɛ-2. Under a generic assumption on the spectral properties of the associated cell problem, we prove that the solution can be approximately factorized as the product of a fast oscillating cell eigenfunction and of a slowly varying solution of a scalar second-order equation. This result applies to various types of equations such as parabolic, hyperbolic or eigenvalue problems, as well as fourth-order plate equation. We also prove that, for well-prepared initial data concentrating at the bottom of a Bloch band, the resulting homogenized tensor depends on the chosen Bloch band. Our method is based on a combination of classical homogenization techniques (two-scale convergence and suitable oscillating test functions) and of Bloch waves decomposition.
Central configurations, periodic orbits, and Hamiltonian systems
Llibre, Jaume; Simó, Carles
2015-01-01
The notes of this book originate from three series of lectures given at the Centre de Recerca Matemàtica (CRM) in Barcelona. The first one is dedicated to the study of periodic solutions of autonomous differential systems in Rn via the Averaging Theory and was delivered by Jaume Llibre. The second one, given by Richard Moeckel, focusses on methods for studying Central Configurations. The last one, by Carles Simó, describes the main mechanisms leading to a fairly global description of the dynamics in conservative systems. The book is directed towards graduate students and researchers interested in dynamical systems, in particular in the conservative case, and aims at facilitating the understanding of dynamics of specific models. The results presented and the tools introduced in this book include a large range of applications.
Multiphase patterns in periodically forced oscillatory systems
Energy Technology Data Exchange (ETDEWEB)
Elphick, C. [Centro de Fisica No Lineal y Sistemas Complejos de Santiago, Casilla 17122, Santiago (Chile); Hagberg, A. [Theoretical Division and Center for Nonlinear Studies, MSB284, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Meron, E. [The Jacob Blaustein Institute for Desert Research and the Physics Department, Ben-Gurion University, Sede Boker Campus 84990 (Israel)
1999-05-01
Periodic forcing of an oscillatory system produces frequency locking bands within which the system frequency is rationally related to the forcing frequency. We study extended oscillatory systems that respond to uniform periodic forcing at one quarter of the forcing frequency (the 4:1 resonance). These systems possess four coexisting stable states, corresponding to uniform oscillations with successive phase shifts of {pi}/2. Using an amplitude equation approach near a Hopf bifurcation to uniform oscillations, we study front solutions connecting different phase states. These solutions divide into two groups: {pi} fronts separating states with a phase shift of {pi} and {pi}/2 fronts separating states with a phase shift of {pi}/2. We find a type of front instability where a stationary {pi} front {open_quotes}decomposes{close_quotes} into a pair of traveling {pi}/2 fronts as the forcing strength is decreased. The instability is degenerate for an amplitude equation with cubic nonlinearities. At the instability point a continuous family of pair solutions exists, consisting of {pi}/2 fronts separated by distances ranging from zero to infinity. Quintic nonlinearities lift the degeneracy at the instability point but do not change the basic nature of the instability. We conjecture the existence of similar instabilities in higher 2n:1 resonances (n=3,4,{hor_ellipsis}) where stationary {pi} fronts decompose into {ital n} traveling {pi}/n fronts. The instabilities designate transitions from stationary two-phase patterns to traveling 2n-phase patterns. As an example, we demonstrate with a numerical solution the collapse of a four-phase spiral wave into a stationary two-phase pattern as the forcing strength within the 4:1 resonance is increased. {copyright} {ital 1999} {ital The American Physical Society}
Periodic thermodynamics of open quantum systems
Brandner, Kay; Seifert, Udo
2016-06-01
The thermodynamics of quantum systems coupled to periodically modulated heat baths and work reservoirs is developed. By identifying affinities and fluxes, the first and the second law are formulated consistently. In the linear response regime, entropy production becomes a quadratic form in the affinities. Specializing to Lindblad dynamics, we identify the corresponding kinetic coefficients in terms of correlation functions of the unperturbed dynamics. Reciprocity relations follow from symmetries with respect to time reversal. The kinetic coefficients can be split into a classical and a quantum contribution subject to an additional constraint, which follows from a natural detailed balance condition. This constraint implies universal bounds on efficiency and power of quantum heat engines. In particular, we show that Carnot efficiency cannot be reached whenever quantum coherence effects are present, i.e., when the Hamiltonian used for work extraction does not commute with the bare system Hamiltonian. For illustration, we specialize our universal results to a driven two-level system in contact with a heat bath of sinusoidally modulated temperature.
On periodic orbits in discrete-time cascade systems
Directory of Open Access Journals (Sweden)
Huimin Li
2006-01-01
Full Text Available We present some results on existence, minimum period, number of periodic orbits, and stability of periodic orbits in discrete-time cascade systems. Some examples are presented to illustrate these results.
Almost periodic solutions for Lotka-Volterra systems with delays
Liang, Yanlai; Li, Lijie; Chen, Lansun
2009-09-01
This paper studies a general class of delayed almost periodic Lotka-Volterra system with time-varying delays and distributed delays. By using the definition of almost periodic function, the sufficient conditions for the existence and uniqueness of globally exponentially stable almost periodic solution are obtained. The conditions can be easily reduced to special cases of cooperative systems and competitive systems.
Positive periodic solutions of periodic neutral Lotka-Volterra system with state dependent delays
Li, Yongkun
2007-06-01
By using a fixed point theorem of strict-set-contraction, some new criteria are established for the existence of positive periodic solutions of the following periodic neutral Lotka-Volterra system with state dependent delays where (i,j=1,2,...,n) are [omega]-periodic functions and (i=1,2,...,n) are [omega]-periodic functions with respect to their first arguments, respectively.
Energy Technology Data Exchange (ETDEWEB)
Sun Wen [School of Mathematics and Statistics, Wuhan University, Wuhan 430072 (China); Chen Shihua [School of Mathematics and Statistics, Wuhan University, Wuhan 430072 (China)]. E-mail: shcheng@whu.edu.cn; Hong Zhiming [School of Mathematics and Statistics, Wuhan University, Wuhan 430072 (China); Wang Changping [Department of Mathematics and Statistics, Dalhousie University, Halifax, NS, B3H 3J5 (Canada)
2007-08-15
A two-species periodic competition Lotka-Volterra system with time delay and diffusion is investigated. Some sufficient conditions of the existence of positive periodic solution are established for the system by using the continuation theorem of coincidence degree theory.
International Nuclear Information System (INIS)
A spectral method different from previously known methods has been proposed for the study of nonautonomous systems of ordinary differential equations with periodic and polynomially periodic matrices. The asymptotic expression has been constructed for solutions of linear systems of this class
COEXISTING PERIODIC ORBITS IN VIBRO-IMPACTING DYNAMICAL SYSTEMS
Institute of Scientific and Technical Information of China (English)
李群宏; 陆启韶
2003-01-01
A method is presented to seek for coexisting periodic orbits which may be stable or unstable in piecewise-linear vibro-impacting systems. The conditions for coexistence of single impact periodic orbits are derived, and in particular, it is investigated in details how to assure that no other impacts will happen in an evolution period of a single impact periodic motion. Furthermore, some criteria for nonexistence of single impact periodic orbits with specific periods are also established. Finally, the stability of coexisting periodic orbits is discussed, and the corresponding computation formula is given. Examples of numerical simulation are in good agreement with the theoretic analysis.
Periodically sheared 2D Yukawa systems
Energy Technology Data Exchange (ETDEWEB)
Kovács, Anikó Zsuzsa [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly-Thege Miklós str. 29-33, H-1121 Budapest (Hungary); Hartmann, Peter [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly-Thege Miklós str. 29-33, H-1121 Budapest (Hungary); Center for Astrophysics, Space Physics and Engineering Research (CASPER), One Bear Place 97310, Baylor University, Waco, Texas 76798 (United States); Donkó, Zoltán [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly-Thege Miklós str. 29-33, H-1121 Budapest (Hungary); Physics Department, Boston College, Chestnut Hill, Massachusetts 20467 (United States)
2015-10-15
We present non-equilibrium molecular dynamics simulation studies on the dynamic (complex) shear viscosity of a 2D Yukawa system. We have identified a non-monotonic frequency dependence of the viscosity at high frequencies and shear rates, an energy absorption maximum (local resonance) at the Einstein frequency of the system at medium shear rates, an enhanced collective wave activity, when the excitation is near the plateau frequency of the longitudinal wave dispersion, and the emergence of significant configurational anisotropy at small frequencies and high shear rates.
Almost Periodic Solution of a Discrete Commensalism System
Directory of Open Access Journals (Sweden)
Yalong Xue
2015-01-01
Full Text Available A nonautonomous discrete two-species Lotka-Volterra commensalism system with delays is considered in this paper. Based on the discrete comparison theorem, the permanence of the system is obtained. Then, by constructing a new discrete Lyapunov functional, a set of sufficient conditions which guarantee the system global attractivity are obtained. If the coefficients are almost periodic, there exists an almost periodic solution and the almost periodic solution is globally attractive.
Almost Periodic Solution of a Discrete Commensalism System
Yalong Xue; Xiangdong Xie; Fengde Chen; Rongyu Han
2015-01-01
A nonautonomous discrete two-species Lotka-Volterra commensalism system with delays is considered in this paper. Based on the discrete comparison theorem, the permanence of the system is obtained. Then, by constructing a new discrete Lyapunov functional, a set of sufficient conditions which guarantee the system global attractivity are obtained. If the coefficients are almost periodic, there exists an almost periodic solution and the almost periodic solution is globally attractive.
Periodic solution of neutral Lotka-Volterra system with periodic delays
Liu, Zhijun; Chen, Lansun
2006-12-01
A nonautonomous n-species Lotka-Volterra system with neutral delays is investigated. A set of verifiable sufficient conditions is derived for the existence of at least one strictly positive periodic solution of this Lotka-Volterra system by applying an existence theorem and some analysis techniques, where the assumptions of the existence theorem are different from that of Gaines and Mawhin's continuation theorem [R.E. Gaines, J.L. Mawhin, Coincidence Degree and Nonlinear Differential Equations, Springer-Verlag, Berlin, 1977] and that of abstract continuation theory for k-set contraction [W. Petryshyn, Z. Yu, Existence theorem for periodic solutions of higher order nonlinear periodic boundary value problems, Nonlinear Anal. 6 (1982) 943-969]. Moreover, a problem proposed by Freedman and Wu [H.I. Freedman, J. Wu, Periodic solution of single species models with periodic delay, SIAM J. Math. Anal. 23 (1992) 689-701] is answered.
Implicit numerical integration for periodic solutions of autonomous nonlinear systems
Thurston, G. A.
1982-01-01
A change of variables that stabilizes numerical computations for periodic solutions of autonomous systems is derived. Computation of the period is decoupled from the rest of the problem for conservative systems of any order and for any second-order system. Numerical results are included for a second-order conservative system under a suddenly applied constant load. Near the critical load for the system, a small increment in load amplitude results in a large increase in amplitude of the response.
Periodically driven three-level systems
Kenmoe, M. B.; Fai, L. C.
2016-09-01
We study the dynamics of a three-level system (ThLS) sinusoidally driven in both longitudinal and transverse directions and in the presence of a uniaxial anisotropy D entering the generic Hamiltonian through the zero-energy splitting term D (Sz)2 where Sz is the projection of the spin vector along the quantization direction. As a consequence of the addition of this term, the order of the symmetry group of the Hamiltonian is increased by a unit and we observe a sequence of cascaded SU(3) Landau-Zener-Stückelberg-Majorana (LZSM) interferometers. The study is carried out by analytically and numerically calculating the probabilities of nonadiabatic and adiabatic evolutions. For nonadiabatic evolutions, two main approximations based on the weak and strong driving limits are discussed by comparing the characteristic frequency of the longitudinal drive with the amplitudes of driven fields. For each of the cases discussed, our analytical results quite well reproduce the gross temporal profile of the exact numerical probabilities. This allows us to check the range of validity of analytical results and confirm our assumptions. For adiabatic evolutions, a general theory is constructed allowing for the description of adiabatic passages in arbitrary ThLSs in which direct transitions between states with extremal spin projections are forbidden. A compact formula for adiabatic evolutions is derived and numerically tested for some illustrative cases. Interference patterns demonstrating multiple LZSM transitions are reported. Applications of our results to the nitrogen vacancy center in diamond are discussed.
The linking number in systems with Periodic Boundary Conditions
Panagiotou, E.
2015-11-01
Periodic Boundary Conditions (PBC) are often used for the simulation of complex physical systems. Using the Gauss linking number, we define the periodic linking number as a measure of entanglement for two oriented curves in a system employing PBC. In the case of closed chains in PBC, the periodic linking number is an integer topological invariant that depends on a finite number of components in the periodic system. For open chains, the periodic linking number is an infinite series that accounts for all the topological interactions in the periodic system. In this paper we give a rigorous proof that the periodic linking number is defined for the infinite system, i.e., that it converges for one, two, and three PBC models. It gives a real number that varies continuously with the configuration and gives a global measure of the geometric complexity of the system of chains. Similarly, for a single oriented chain, we define the periodic self-linking number and prove that it also is defined for open chains. In addition, we define the cell periodic linking and self-linking numbers giving localizations of the periodic linking numbers. These can be used to give good estimates of the periodic linking numbers in infinite systems. We also define the local periodic linking number associated to chains in the immediate cell neighborhood of a chain in order to study local linking measures in contrast to the global linking measured by the periodic linking numbers. Finally, we study and compare these measures when applied to a PBC model of polyethylene melts.
Lorenz, Daniel S.; Reiman, Michael P.; Walker, John C.
2010-01-01
Background: Clinicians are constantly faced with the challenge of designing training programs for injured and noninjured athletes that maximize healing and optimize performance. Periodization is a concept of systematic progression—that is, resistance training programs that follow predictable patterns of change in training variables. The strength training literature is abundant with studies comparing periodization schemes on uninjured, trained, and untrained athletes. The rehabilitation litera...
ON THE ALMOST PERIODIC KOLMOGOROV COMPETITIVE SYSTEMS WITH FEEDBACK CONTROLS
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
In this paper, we consider an almost periodic multi-species Kolmogorov type com-petitive system with feedback controls. Applying Schauder's fixed point theorem, a criterion on the existence of the positive almost periodic solution to the system is obtained. Our results improve and generalize some existing conclusions.
PERIODIC SIGNAL DETECTION WITH USING DUFFING SYSTEM POINCARE MAP ANALYSIS
Directory of Open Access Journals (Sweden)
Valeriy Martynyuk
2014-06-01
Full Text Available In this article the periodic signal detection method on the base of Duffing system chaotic oscillations analysis is presented. This work is a development of the chaos-based signal detection technique. Generally, chaos-based signal detection is the detection of chaotic-to-periodic state transition under input periodic component influence. If the input periodic component reaches certain threshold value, the system transforms from chaotic state to periodic state. The Duffing-type chaotic systems are often used for such a signal detection purpose because of their ability to work in chaotic state for a long time and relatively simple realization. The main advantage of chaos-based signal detection methods is the utilization of chaotic system sensitivity to weak signals. But such methods are not used in practice because of the chaotic system state control problems. The method presented does not require an exact system state control. The Duffing system works continuously in chaotic state and the periodic signal detection process is based on the analysis of Duffing system Poincare map fractal structure. This structure does not depend on noise, and therefore the minimum input signal-to-noise ratio required for periodic signal detection is not limited by chaotic system state control tolerance.
Quasi-periodic and Non-periodic Waves in (2+1)-Dimensional Nonlinear Systems
Institute of Scientific and Technical Information of China (English)
TANG Xiao-Yan; LOU Sen-Yue
2005-01-01
New exact quasi-periodic and non-periodic solutions for the (2 + 1)-dimensional nonlinear systems are studied by means of the multi-linear variable separation approach (MLVSA) and the Jacobi elliptic functions with the space-time-dependent modulus. Though the result is valid for all the MLVSA solvable models, it is explicitly shown for the long-wave and short-wave interaction model.
Near-periodical spin period evolution in the binary system LMC X-4
Molkov, S; Falanga, M; Tsygankov, S; Bozzo, E
2016-01-01
In this paper we investigated the long-term evolution of the pulse-period in the high-mass X-ray binary LMC X-4 by taking advantage of more than 43~yrs of measurements in the X-ray domain. Our analysis revealed for the first time that the source is displaying near-periodical variations of its spin period on a time scale of roughly 6.8~yrs, making LMC X-4 one of the known binary systems showing remarkable long term spin torque reversals. We discuss different scenarios to interpret the origin of these torque reversals.
Periodic Table of the Elements in the Perspective of Artificial Neural Networks
Lemes, Mauricio R.; Dal Pino, Arnaldo
2011-01-01
Although several chemical elements were not known by end of the 19th century, Mendeleev came up with an astonishing achievement, the periodic table of elements. He was not only able to predict the existence of (then) new elements, but also to provide accurate estimates of their chemical and physical properties. This is a profound example of the…
Satisfactory control of discrete-time linear periodic systems
Institute of Scientific and Technical Information of China (English)
Shiqian LIU; Jihong ZHU; JinChun HU
2007-01-01
In this paper satisfactory control for discrete-time linear periodic systems is studied.Based on a suitable time-invariant state sampled reformulation,periodic state feedback controller has been designed such that desired requirements of steady state covariance,H-infinity rejection bound and regional pole assignment for the periodic system are met simultaneously.By using satisfactory control theory,the problem of satisfactory periodic controller can be transformed into a linear programming problem subject to a set of linear matrix inequalities(LMIs).and a feasible designing approach is presented via LMI technique.Numeric example validates the obtained conclusion.
Quasi-periodicity in the autonomous glycolytic system
Institute of Scientific and Technical Information of China (English)
GAO Qingyu; ZHANG Lu; ZHANG Xing; WANG Jichang
2005-01-01
This study predicts that quasi-periodic oscilla-tions could exist in a detailed model of glycolysis that is ana-lyzed in an autonomous system. In addition to period-dou- bling, quasi-periodic and period-adding bifurcation, a new stationary branch, which lies in between the thermodynamic and flow branches, is also uncovered in the glycolytic reac-tion system. Results presented in this study illustrate that the Michaelis constant (K4GAP) of glyceraldehyde 3-phosphate dehydrogenase for glyceraldehyde 3-phosphate has great influences on glycolytic oscillations, in which increasing K4GAP widens the range of flow rate over which quasi-peri- odic oscillations exist.
Early warning signals of tipping points in periodically forced systems
Williamson, Mark S.; Bathiany, Sebastian; Lenton, Timothy M.
2016-04-01
The prospect of finding generic early warning signals of an approaching tipping point in a complex system has generated much interest recently. Existing methods are predicated on a separation of timescales between the system studied and its forcing. However, many systems, including several candidate tipping elements in the climate system, are forced periodically at a timescale comparable to their internal dynamics. Here we use alternative early warning signals of tipping points due to local bifurcations in systems subjected to periodic forcing whose timescale is similar to the period of the forcing. These systems are not in, or close to, a fixed point. Instead their steady state is described by a periodic attractor. For these systems, phase lag and amplification of the system response can provide early warning signals, based on a linear dynamics approximation. Furthermore, the Fourier spectrum of the system's time series reveals harmonics of the forcing period in the system response whose amplitude is related to how nonlinear the system's response is becoming with nonlinear effects becoming more prominent closer to a bifurcation. We apply these indicators as well as a return map analysis to a simple conceptual system and satellite observations of Arctic sea ice area, the latter conjectured to have a bifurcation type tipping point. We find no detectable signal of the Arctic sea ice approaching a local bifurcation.
Tang, Xianhua; Cao, Daomin; Zou, Xingfu
We consider a periodic Lotka-Volterra competition system without instantaneous negative feedbacks (i.e., pure-delay systems) x(t)=x(t)[r(t)-∑j=1na(t)x(t-τ(t))], i=1,2,…,n. We establish some 3/2-type criteria for global attractivity of a positive periodic solution of the system, which generalize the well-known Wright's 3/2 criteria for the autonomous delay logistic equation, and thereby, address the open problem proposed by both Kuang [Y. Kuang, Global stability in delayed nonautonomous Lotka-Volterra type systems without saturated equilibria, Differential Integral Equations 9 (1996) 557-567] and Teng [Z. Teng, Nonautonomous Lotka-Volterra systems with delays, J. Differential Equations 179 (2002) 538-561].
Periodic solutions of nonautonomous differential systems modeling obesity population
Energy Technology Data Exchange (ETDEWEB)
Arenas, Abraham J. [Departamento de Matematicas y Estadistica, Universidad de Cordoba Monteria (Colombia)], E-mail: aarenas@sinu.unicordoba.edu.co; Gonzalez-Parra, Gilberto [Departamento de Calculo, Universidad de los Andes, Merida (Venezuela, Bolivarian Republic of)], E-mail: gcarlos@ula.ve; Jodar, Lucas [Instituto de Matematica Multidisciplinar, Universidad Politecnica de Valencia Edificio 8G, 2o, 46022 Valencia (Spain)], E-mail: ljodar@imm.upv.es
2009-10-30
In this paper we study the periodic behaviour of the solutions of a nonautonomous model for obesity population. The mathematical model represented by a nonautonomous system of nonlinear ordinary differential equations is used to model the dynamics of obese populations. Numerical simulations suggest periodic behaviour of subpopulations solutions. Sufficient conditions which guarantee the existence of a periodic positive solution are obtained using a continuation theorem based on coincidence degree theory.
Three positive doubly periodic solutions of a nonlinear telegraph system
Institute of Scientific and Technical Information of China (English)
Fang-lei WANG; Yu-kun AN
2009-01-01
This paper studies existence of at least three positive doubly periodic solutions of a coupled nonlinear telegraph system with doubly periodic boundary conditions. First, by using the Green function and maximum principle, existence of solutions of a nonlinear telegraph system is equivalent to existence of fixed points of an operator. By imposing growth conditions on the nonlinearities, existence of at least three fixed points in cone is obtained by using the Leggett-Williams fixed point theorem to cones in ordered Banach spaces. In other words, there exist at least three positive doubly periodic solutions of nonlinear telegraph system.
Nonlinear Stability of Periodic Traveling Waves of the BBM System
Hakkaev, S.
2013-01-01
This paper is concerned with the nonlinear stability of periodic traveling wave solutions for the coupled Benjamin-Bona-Mahony system. We show the existence of a family of dnoidal type traveling waves. We find conditions on parameters of the waves which imply the nonlinear stability of periodic traveling waves.
Four positive periodic solutions for the first order differential system
Zhang, Zhengqiu; Tang, Hengsheng
2007-08-01
In this paper, we establish the existence of four positive periodic solutions for the first order differential system by using the continuation theorem of coincidence degree theory. When our result is applied to a competition Lotka-Volterra population model, we obtain the existence of four positive periodic solutions for this model.
Distribution of periodic trajectories of Anosov C-system
Görlich, Andrzej; Savvidy, Konstantin; Savvidy, George
2016-01-01
The hyperbolic Anosov C-systems have a countable set of everywhere dense periodic trajectories which have been recently used to generate pseudorandom numbers. The asymptotic distribution of periodic trajectories of C-systems with periods less than a given number is well known, but a deviation of this distribution from its asymptotic behaviour is less known. Using fast algorithms, we are studying the exact distribution of periodic trajectories and their deviation from asymptotic behaviour for hyperbolic C-systems which are defined on high dimensional tori and are used for Monte-Carlo simulations. A particular C-system which we consider in this article is the one which was implemented in the MIXMAX generator of pseudorandom numbers. The generator has the best combination of speed, reasonable size of the state, and availability for implementing the parallelization and is currently available generator in the ROOT and CLHEP software packages at CERN.
Real numbers having ultimately periodic representations in abstract numeration systems
Lecomte, P.; Rigo, M
2002-01-01
Using a genealogically ordered infinite regular language, we know how to represent an interval of R. Numbers having an ultimately periodic representation play a special role in classical numeration systems. The aim of this paper is to characterize the numbers having an ultimately periodic representation in generalized systems built on a regular language. The syntactical properties of these words are also investigated. Finally, we show the equivalence of the classical "theta"-expansions with o...
Lyapunov spectra of Coulombic and gravitational periodic systems
Kumar, Pankaj
2016-01-01
We compute Lyapunov spectra for Coulombic and gravitational versions of the one-dimensional systems of parallel sheets with periodic boundary conditions. Exact time evolution of tangent-space vectors are derived and are utilized toward computing Lypaunov characteristic exponents using an event-driven algorithm. The results indicate that the energy dependence of the largest Lyapunov exponent emulates that of Kolmogorov-entropy density for each system at different degrees of freedom. Our approach forms an effective and approximation-free tool toward studying the dynamical properties exhibited by the Coulombic and gravitational systems and finds applications in investigating indications of thermodynamic transitions in large versions of the spatially periodic systems.
Exponentially Slow Heating in Periodically Driven Many-Body Systems.
Abanin, Dmitry A; De Roeck, Wojciech; Huveneers, François
2015-12-18
We derive general bounds on the linear response energy absorption rates of periodically driven many-body systems of spins or fermions on a lattice. We show that, for systems with local interactions, the energy absorption rate decays exponentially as a function of driving frequency in any number of spatial dimensions. These results imply that topological many-body states in periodically driven systems, although generally metastable, can have very long lifetimes. We discuss applications to other problems, including the decay of highly energetic excitations in cold atomic and solid-state systems. PMID:26722939
Perturbative solution of Vlasov equation for periodically driven systems
Shah, Kushal
2015-01-01
Statistical systems with time-periodic spatially non-uniform forces are of immense importance in several areas of physics. In this paper, we provide an analytical expression of the time-periodic probability distribution function of particles in such a system by perturbatively solving the 1D Vlasov equation in the limit of high frequency and slow spatial variation of the time-periodic force. We find that the time-averaged distribution function and density cannot be written simply in terms of an effective potential, also known as the fictitious ponderomotive potential. We also find that the temperature of such systems is spatially non-uniform leading to a non-equilibrium steady state which can further lead to a complex statistical time evolution of the system. Finally, we outline a method by which one can use these analytical solutions of the Vlasov equation to obtain numerical solutions of the self-consistent Vlasov-Poisson equations for such systems.
Stroboscopic prethermalization in weakly interacting periodically driven systems.
Canovi, Elena; Kollar, Marcus; Eckstein, Martin
2016-01-01
Time-periodic driving provides a promising route toward engineering nontrivial states in quantum many-body systems. However, while it has been shown that the dynamics of integrable, noninteracting systems can synchronize with the driving into a nontrivial periodic motion, generic nonintegrable systems are expected to heat up until they display a trivial infinite-temperature behavior. In this paper we show that a quasiperiodic time evolution over many periods can also emerge in weakly interacting systems, with a clear separation of the timescales for synchronization and the eventual approach of the infinite-temperature state. This behavior is the analog of prethermalization in quenched systems. The synchronized state can be described using a macroscopic number of approximate constants of motion. We corroborate these findings with numerical simulations for the driven Hubbard model.
Lei, Ling
2009-01-01
This work studies the stabilization for a periodic parabolic system under perturbations in the system conductivity. A perturbed system does not have any periodic solution in general. However, we will prove that the perturbed system can always be pulled back to a periodic system after imposing a control from a fixed finite dimensional subspace.
Pseudo analytical solution to time periodic stiffness systems
Institute of Scientific and Technical Information of China (English)
Wang Yan-Zhong; Zhou Yuan-Zi
2011-01-01
An analytical form of state transition matrix for a system of equations with time periodic stiffness is derived in order to solve the free response and also allow for the determination of system stability and bifurcation. A pseudoclosed form complete solution for parametrically excited systems subjected to inhomogeneous generalized forcing is developed, based on the Fourier expansion of periodic matrices and the substitution of matrix exponential terms via Lagrange-Sylvester theorem. A Mathieu type of equation with large amplitude is presented to demonstrate the method of formulating state transition matrix and Floquet multipliers. A two-degree-of-freedom system with irregular time periodic stiffness characterized by spiral bevel gear mesh vibration is presented to find forced response in stability and instability. The obtained results are presented and discussed.
Bifurcations, Period doubling and chaos in clarinet-like systems
Maganza, Christian; Caussé, René; Laloë, Franck
1986-01-01
Wind instruments provide interesting hydrodynamical systems where non-linearities are important but well localized. A simple analysis shows that these systems should undergo Feignebaum-type route to chaos, with a cascade of period doublings. Experiments have been performed fo confirm these predictions
Electrostatics of solvated systems in periodic boundary conditions
Andreussi, Oliviero; Marzari, Nicola
2014-01-01
Continuum solvation methods can provide an accurate and inexpensive embedding of quantum simulations in liquid or complex dielectric environments. Notwithstanding a long history and manifold applications to isolated systems in open boundary conditions, their extension to materials simulations --- typically entailing periodic-boundary conditions --- is very recent, and special care is needed to address correctly the electrostatic terms. We discuss here how periodic-boundary corrections develop...
Periodic solutions and flip bifurcation in a linear impulsive system
Institute of Scientific and Technical Information of China (English)
Jiang Gui-Rong; Yang Qi-Gui
2008-01-01
In this paper,the dynamical behaviour of a linear impulsive system is discussed both theoretically and numerically.The existence and the stability of period-one solution are discussed by using a discrete map.The conditions of existence for flip bifurcation are derived by using the centre manifold theorem and bifurcation theorem.The bifurcation analysis shows that chaotic solutions appear via a cascade of period-doubling in some interval of parameters.Moreover,the periodic solutions,the bifurcation diagram,and the chaotic attractor,which show their consistence with the theoretical analyses,are given in an example.中图分类:O547
Development of Seismic Isolation Systems Using Periodic Materials
Energy Technology Data Exchange (ETDEWEB)
Yan, Yiqun [Univ. of Houston, Houston, TX (United States); Mo, Yi-Lung [Univ. of Houston, Houston, TX (United States); Menq, Farn-Yuh [Univ. of Texas, Austin, TX (United States); Stokoe, II, Kenneth H. [Univ. of Texas, Austin, TX (United States); Perkins, Judy [Prairie View A & M University, Prairie View, TX (United States); Tang, Yu [Argonne National Lab. (ANL), Argonne, IL (United States)
2014-12-10
Advanced fast nuclear power plants and small modular fast reactors are composed of thin-walled structures such as pipes; as a result, they do not have sufficient inherent strength to resist seismic loads. Seismic isolation, therefore, is an effective solution for mitigating earthquake hazards for these types of structures. Base isolation, on which numerous studies have been conducted, is a well-defined structure protection system against earthquakes. In conventional isolators, such as high-damping rubber bearings, lead-rubber bearings, and friction pendulum bearings, large relative displacements occur between upper structures and foundations. Only isolation in a horizontal direction is provided; these features are not desirable for the piping systems. The concept of periodic materials, based on the theory of solid-state physics, can be applied to earthquake engineering. The periodic material is a material that possesses distinct characteristics that prevent waves with certain frequencies from being transmitted through it; therefore, this material can be used in structural foundations to block unwanted seismic waves with certain frequencies. The frequency band of periodic material that can filter out waves is called the band gap, and the structural foundation made of periodic material is referred to as the periodic foundation. The design of a nuclear power plant, therefore, can be unified around the desirable feature of a periodic foundation, while the continuous maintenance of the structure is not needed. In this research project, three different types of periodic foundations were studied: one-dimensional, two-dimensional, and three-dimensional. The basic theories of periodic foundations are introduced first to find the band gaps; then the finite element methods are used, to perform parametric analysis, and obtain attenuation zones; finally, experimental programs are conducted, and the test data are analyzed to verify the theory. This procedure shows that the
Phase control of resonant systems: interference, chaos and high periodicity.
Greenman, J V; Pasour, V B
2011-06-01
Much progress has been made in understanding the effect of periodic forcing on epidemiological and ecological systems when that forcing acts on just one part of the system. Much less is known about situations in which several parts of the system are affected. In this case the interaction between the impacts of the different forcing components can lead to reinforcement of system responses or to their interference. This interference phenomenon is significant if some forcing components are anthropogenic for then management might be able to exercise sufficient control to bring about suppression of undesirable aspects of the forcing, for example resonant amplification and the problems this can cause. We set out the algebraic theory when forcing is weak and illustrate by example what can happen when forcing is strong enough to create subharmonics and chaotic states. Phase is the key control variable that can bring about interference, advantageously shift nonlinear response curves and create periodic states out of chaos. The phenomenon in which high period fluctuations appear to be generated by low period forcing is examined and different mechanisms compared in a two-strain epidemiological model. The effect of noise as a source of high period fluctuations is also considered. PMID:21397609
Characterization of a periodically driven chaotic dynamical system
Crisanti, A; Lacorata, G; Purini, R; Crisanti, A
1996-01-01
We discuss how to characterize the behavior of a chaotic dynamical system depending on a parameter that varies periodically in time. In particular, we study the predictability time, the correlations and the mean responses, by defining a local--in--time version of these quantities. In systems where the time scale related to the time periodic variation of the parameter is much larger than the ``internal'' time scale, one has that the local quantities strongly depend on the phase of the cycle. In this case, the standard global quantities can give misleading information.
Periodic properties of the histaminergic system of the mouse brain.
Rozov, Stanislav V; Zant, Janneke C; Karlstedt, Kaj; Porkka-Heiskanen, Tarja; Panula, Pertti
2014-01-01
Brain histamine is involved in the regulation of the sleep-wake cycle and alertness. Despite the widespread use of the mouse as an experimental model, the periodic properties of major markers of the mouse histaminergic system have not been comprehensively characterized. We analysed the daily levels of histamine and its first metabolite, 1-methylhistamine, in different brain structures of C57BL/6J and CBA/J mouse strains, and the mRNA level and activity of histidine decarboxylase and histamine-N-methyltransferase in C57BL/6J mice. In the C57BL/6J strain, histamine release, assessed by in vivo microdialysis, underwent prominent periodic changes. The main period was 24 h peaking during the activity period. Additional 8 h periods were also observed. The release was highly positively correlated with active wakefulness, as shown by electroencephalography. In both mouse strains, tissue histamine levels remained steady for 24 h in all structures except for the hypothalamus of CBA/J mice, where 24-h periodicity was observed. Brain tissue 1-methylhistamine levels in both strains reached their maxima in the periods of activity. The mRNA level of histidine decarboxylase in the tuberomamillary nucleus and the activities of histidine decarboxylase and histamine-N-methyltransferase in the striatum and cortex did not show a 24-h rhythm, whereas in the hypothalamus the activities of both enzymes had a 12-h periodicity. These results show that the activities of histamine-metabolizing enzymes are not under simple direct circadian regulation. The complex and non-uniform temporal patterns of the histaminergic system of the mouse brain suggest that histamine is strongly involved in the maintenance of active wakefulness.
Periodic orbits near heteroclinic cycles in a cyclic replicator system.
Wang, Yuanshi; Wu, Hong; Ruan, Shigui
2012-04-01
A species is semelparous if every individual reproduces only once in its life and dies immediately after the reproduction. While the reproduction opportunity is unique per year and the individual's period from birth to reproduction is just n years, the individuals that reproduce in the ith year (modulo n) are called the ith year class, i = 1, 2, . . . , n. The dynamics of the n year-class system can be described by a differential equation system of Lotka-Volterra type. For the case n = 4, there is a heteroclinic cycle on the boundary as shown in previous works. In this paper, we focus on the case n = 4 and show the existence, growth and disappearance of periodic orbits near the heteroclinic cycle, which is a part of the conjecture by Diekmann and van Gils (SIAM J Appl Dyn Syst 8:1160-1189, 2009). By analyzing the Poincaré map near the heteroclinic cycle and introducing a metric to measure the size of the periodic orbit, we show that (i) when the average competitive degree among subpopulations (year classes) in the system is weak, there exists an asymptotically stable periodic orbit near the heteroclinic cycle which is repelling; (ii) the periodic orbit grows in size when some competitive degree increases, and converges to the heteroclinic cycle when the average competitive degree tends to be strong; (iii) when the average competitive degree is strong, there is no periodic orbit near the heteroclinic cycle which becomes asymptotically stable. Our results provide explanations why periodic solutions expand and disappear and why all but one subpopulation go extinct. PMID:21656008
Directed transport of coupled systems in symmetric periodic potentials
Institute of Scientific and Technical Information of China (English)
郑志刚; 刘凤芝; 高建
2003-01-01
In this paper, we discuss the damped unidirectional motions of a coupled lattice in a periodic potential. Each particle in the lattice is subject to a time-periodic ac force. Our studies reveal that a directed transport process can be observed when the ac forces acting on the coupled lattice have a phase shift (mismatch). This directed motion is a collaboration of the coupling, the substrate potential, and the periodic force, which are all.symmetric. The absence of any one of these three factors will not give rise to a directed current. We discuss the complex relations between the directed current and parameters in the system. Results in this paper can be accomplished in experiments. Moreover,our results can be generalized to the studies of directed transport processes in more complicated spatially extended systems.
Kubo formulas for dispersion in heterogeneous periodic nonequilibrium systems.
Guérin, T; Dean, D S
2015-12-01
We consider the dispersion properties of tracer particles moving in nonequilibrium heterogeneous periodic media. The tracer motion is described by a Fokker-Planck equation with arbitrary spatially periodic (but constant in time) local diffusion tensors and drifts, eventually with the presence of obstacles. We derive a Kubo-like formula for the time-dependent effective diffusion tensor valid in any dimension. From this general formula, we derive expressions for the late time effective diffusion tensor and drift in these systems. In addition, we find an explicit formula for the late finite-time corrections to these transport coefficients. In one dimension, we give a closed analytical formula for the transport coefficients. The formulas derived here are very general and provide a straightforward method to compute the dispersion properties in arbitrary nonequilibrium periodic advection-diffusion systems. PMID:26764628
Positive periodic solutions of periodic neutral Lotka-Volterra system with distributed delays
Energy Technology Data Exchange (ETDEWEB)
Li Yongkun [Department of Mathematics, Yunnan University Kunming, Yunnan 650091 (China)], E-mail: yklie@ynu.edu.cn
2008-07-15
By using a fixed point theorem of strict-set-contraction, some criteria are established for the existence of positive periodic solutions of the following periodic neutral Lotka-Volterra system with distributed delays (dx{sub i}(t))/(dt) =x{sub i}(t)[a{sub i}(t)-{sigma}{sub j=1}{sup n}b{sub ij}(t){integral}{sub -T{sub ij}}{sup 0}K{sub ij}({theta})x{sub j}( t+{theta})d{theta}-{sigma}{sub j=1}{sup n}c{sub ij}(t){integral}{sub -T{sub ij}}{sup 0}K{sub ij}({theta}) x{sub j}{sup '}(t+{theta})d{theta}],i=1,2,...,n, where a{sub i},b{sub ij},c{sub ij} element of C(R,R{sup +}) (i, j = 1, 2, ..., n) are {omega}-periodic functions, T{sub ij},T{sub ij} element of (0,{infinity}) (i, j = 1, 2, ..., n) and K{sub ij},K{sub ij} element of (R,R{sup +}) satisfying {integral}{sub -T{sub ij}}{sup 0}K{sub ij}({theta})d{theta}=1,{integral}{sub -T{sub ij}}{sup 0}K{sub ij}({theta})d{theta}=1, i, j = 1, 2, ..., n.
PERIODIC-ORBITS IN K-SYMMETRICAL DYNAMICAL-SYSTEMS
BRANDS, H; LAMB, JSW; HOVEIJN, [No Value
1995-01-01
A map L is called k-symmetric if its kth iterate L(k) possesses more symmetry than L, for some value of k. In k-symmetric systems, there exists a notion of k-symmetric orbits. This paper deals with k-symmetric periodic orbits. We derive a relation between orbits that are k-symmetric with respect to
Periodic Orbits for a Three-Dimensional Biological Differential Systems
Directory of Open Access Journals (Sweden)
Renato Colucci
2013-01-01
Full Text Available We study the existence of periodic orbit for a differential system describing the effects of indirect predation over two preys. Besides discussing a generalized version of the model, we present some remarks and numerical experiments for the nonautonomous version of the two models.
Performance evaluation using periodic system-state measurements
Ellens, W.; Mandjes, M.; Berg, J.L. van den; Worm, D.T.H.; Błaszczuk, S.
2015-01-01
This paper deals with the problem of inferring short time-scale fluctuations of a system's behavior from periodic state measurements. In particular, we devise a novel, efficient procedure to compute four interesting performance metrics for a transient birth-death process on an interval of fixed leng
Transport of quantum states of periodically driven systems
Breuer, H. P.; Dietz, K.; Holthaus, M.
1990-01-01
We discuss the transport of quantum states on quasi-energy surfaces of periodically driven systems and establish their non-trivial structure. The latter is shown to be caused by diabatic transitions at lines of narrow avoided crossings. Some experimental consequences pertaining to adiabatic transport and Landau-Zener transitions among Floquet states are briefly sketched.
Population Growth and Periodic Instability of the International System
Piepers, Ingo
2006-01-01
From the perspective developed in this paper, it can be argued that exponential population growth resulted in the exponential decrease of the life-span of consecutive stable periods during the life-span of the European international system (1480-1945). However, it becomes evident as well that population growth as such is not a sufficient condition to generate a punctuated equilibrium dynamic in the war dynamics of the international system: other conditions and factors - and their interplay - ...
Bifurcation, Period Doublings and Chaos in Clarinetlike Systems
Maganza, Christian; Causse, René; Laloë, Franck
1986-01-01
cote interne IRCAM: Maganza86a / National audience Wind instrument provide interesting hydrodynamical systems where non-linearities are importantbut well localized. A simple analysis shows that these systems should undergo Feigenbaum-typeroute to chaos, with a cascade of period doublings. Experiments have been performed with anacoustical resonator and an "artificial" excitation (nonlinearities controlled by either analogic ordigital devices); they have confirmed these predictions.
Meng, Xinzhu; Chen, Lansun
2008-03-01
This paper studies a nonautonomous Lotka-Volterra dispersal systems with infinite time delay which models the diffusion of a single species into n patches by discrete dispersal. Our results show that the system is uniformly persistent under an appropriate condition. The sufficient condition for the global asymptotical stability of the system is also given. By using Mawhin continuation theorem of coincidence degree, we prove that the periodic system has at least one positive periodic solution, further, obtain the uniqueness and globally asymptotical stability for periodic system. By using functional hull theory and directly analyzing the right functional of almost periodic system, we show that the almost periodic system has a unique globally asymptotical stable positive almost periodic solution. We also show that the delays have very important effects on the dynamic behaviors of the system.
Second-order Green's function perturbation theory for periodic systems
Rusakov, Alexander A
2015-01-01
Despite recent advances, systematic quantitative treatment of the electron correlation problem in extended systems remains a formidable task. Systematically improvable Green's function methods capable of quantitatively describing weak and at least qualitatively strong correlations appear promising candidates for computational treatment of periodic systems. We present a periodic implementation of temperature-dependent self-consistent 2nd-order Green's function method (GF2), where the self-energy is evaluated in the basis of atomic orbitals. Evaluating the real-space self-energy in atomic orbitals and solving the Dyson equation in $\\mathbf{k}$-space are the key components of a computationally feasible algorithm. We apply this technique to the 1D hydrogen lattice - a prototypical crystalline system with a realistic Hamiltonian. By analyzing the behavior of the spectral functions, natural occupations, and self-energies, we claim that GF2 is able to recover metallic, band insulating, and at least qualitatively Mot...
Zhao, Guangyu; Ruan, Shigui
2011-01-01
We study the existence, uniqueness, and asymptotic stability of time periodic traveling wave solutions to a periodic diffusive Lotka-Volterra competition system. Under certain conditions, we prove that there exists a maximal wave speed c* such that for each wave speed c ≤ c*, there is a time periodic traveling wave connecting two semi-trivial periodic solutions of the corresponding kinetic system. It is shown that such a traveling wave is unique modulo translation and is monotone with respect...
Projective synchronization of a hyperchaotic system via periodically intermittent control
Institute of Scientific and Technical Information of China (English)
Huang Jun-Jian; Li Chuan-Dong; Zhang Wei; Wei Peng-Cheng
2012-01-01
We further study the projective synchronization of a new hyperchaotic system.Different from the most existing methods,intermittent control is applied to chaotic synchronization in the present paper.We formulate the intermittent control system that governs the dynamics of the projective synchronization error,then derive the sufficient conditions for the exponential stability of intermittent control system by using the Lyapunov stability theory,and finally establish the periodically intermittent controller according to the stability criterion by which the projective synchronization is expected to be achieved.The analytical results are also demonstrated by several numerical simulations.
Period Changes of the Algol System SZ Herculis
Lee, J. W.; Lee, C.-U.; Kim, S.-L.; Kim, H.-I.; Park, J.-H.; Hinse, T. C.
2012-04-01
New CCD photometric observations of SZ Her were obtained between February and May 2008. More than 1,100 times of minimum light spanning more than one century were used for the period analysis. We find that the orbital period of SZ Her has varied due to a combination of two periodic variations, with cycle lengths of P3 = 85.8 yr and P4 = 42.5 yr and semi-amplitudes of K3 = 0.013 days and K4 = 0.007 days, respectively. The most reasonable explanation for them is a pair of light-time-travel (LTT) effects driven by the existence of two M-type companions with minimum masses of M3 = 0.22 M⊙ and M4 = 0.19 M⊙, located at nearly 2:1 mean motion resonance. Then, SZ Her is a quadruple system and the 3rd and 4th components would stay in the stable orbital resonance.
Electrostatics of solvated systems in periodic boundary conditions
Andreussi, Oliviero; Marzari, Nicola
2014-12-01
Continuum solvation methods can provide an accurate and inexpensive embedding of quantum simulations in liquid or complex dielectric environments. Notwithstanding a long history and manifold applications to isolated systems in open boundary conditions, their extension to materials simulations, typically entailing periodic boundary conditions, is very recent, and special care is needed to address correctly the electrostatic terms. We discuss here how periodic boundary corrections developed for systems in vacuum should be modified to take into account solvent effects, using as a general framework the self-consistent continuum solvation model developed within plane-wave density-functional theory [O. Andreussi et al., J. Chem. Phys. 136, 064102 (2012), 10.1063/1.3676407]. A comprehensive discussion of real- and reciprocal-space corrective approaches is presented, together with an assessment of their ability to remove electrostatic interactions between periodic replicas. Numerical results for zero- and two-dimensional charged systems highlight the effectiveness of the different suggestions, and underline the importance of a proper treatment of electrostatic interactions in first-principles studies of charged systems in solution.
Synchronous 231Pa/230Th Holocene variability from the Mendeleev and Lomonosov Ridges at mid-depths
Hoffmann, S. S.; McManus, J. F.; Curry, W. B.; Brown-Leger, S.
2011-12-01
The Arctic Ocean contributes to global thermohaline circulation through export of intermediate and deep water through Fram Strait; however, the history of formation and circulation of Arctic waters at these depths is little known and presents a major challenge to paleoceanographers. Sedimentary measurements of the uranium-series radionuclides 231Pa and 230Th may provide a means of investigating the past dynamics of these deeper waters. We present 231Pa/230Th records from two well-dated box cores at mid-depths in the Arctic: PL-AR-94 BC 17 from 2255 m on the flank of the Mendeleev Ridge, Makarov Basin, and PL-94-AR BC 28 from 1990 m on the Lomonosov Ridge flank, Amundsen Basin. These records show synchronous millennial-scale variability through the Holocene, with peaks in 231Pa/230Th at 10.5, 7, and 5 ka, interspersed with low ratio values at 8, 6, and 4 ka. Indicators of surface ocean processes at these sites, such as particle fluxes and planktonic δ18O, do not show similar synchronous variation; nor do 231Pa/230Th records from shallower and deeper waters in the central Arctic. We therefore hypothesize that these millennial-scale variations in 231Pa/230Th ratios reflect paleoceanographic changes specific to mid-depth waters across Arctic subbasins, and that these common features may reflect a common source in the core flow of the Arctic Ocean Boundary Current between 1500 and 2500 m.
Floquet analysis of a quantum system with modulated periodic driving
Novičenko, Viktor; Juzeliūnas, Gediminas
2016-01-01
We consider a generic quantum system periodically driven with a strength which varies slowly on the scale of the driving period. The analysis is based on a general formulation of the Floquet theory relying on the extended Hilbert space. In addition to a fast periodic modulation we allow the Hamiltonian to have an extra (slow) time-dependence. The dynamics of the system can then be described in terms of a slowly varying effective Floquet Hamiltonian that captures the long-term evolution, as well as rapidly oscillating micromotion operators. We obtain a systematic high-frequency expansion of all these operators. In contrast to the previous studies, the expanded effective Hamiltonian is now time-dependent and contains extra terms reflecting the modulation of the periodic Hamiltonian. The same applies to the micromotion operators which exhibit a slow temporal dependence in addition to the rapid oscillations. As an illustration, we consider a quantum-mechanical spin in an oscillating magnetic field with a slowly c...
Directory of Open Access Journals (Sweden)
Mario Tolentino
1997-02-01
Full Text Available A history of the periodic table of the elements is presented, from the first tentative classifications, passing through Meyer and Mendeleev, up to recent speculations on super-heavy elements still to be synthesized. Many of the discussions and discoveries related to chemical elements and their proper periodic classification are also presented.
Mario Tolentino; Rocha-Filho, Romeu C.; Aécio Pereira Chagas
1997-01-01
A history of the periodic table of the elements is presented, from the first tentative classifications, passing through Meyer and Mendeleev, up to recent speculations on super-heavy elements still to be synthesized. Many of the discussions and discoveries related to chemical elements and their proper periodic classification are also presented.
Periodic orbits of hybrid systems and parameter estimation via AD
International Nuclear Information System (INIS)
Rhythmic, periodic processes are ubiquitous in biological systems; for example, the heart beat, walking, circadian rhythms and the menstrual cycle. Modeling these processes with high fidelity as periodic orbits of dynamical systems is challenging because: (1) (most) nonlinear differential equations can only be solved numerically; (2) accurate computation requires solving boundary value problems; (3) many problems and solutions are only piecewise smooth; (4) many problems require solving differential-algebraic equations; (5) sensitivity information for parameter dependence of solutions requires solving variational equations; and (6) truncation errors in numerical integration degrade performance of optimization methods for parameter estimation. In addition, mathematical models of biological processes frequently contain many poorly-known parameters, and the problems associated with this impedes the construction of detailed, high-fidelity models. Modelers are often faced with the difficult problem of using simulations of a nonlinear model, with complex dynamics and many parameters, to match experimental data. Improved computational tools for exploring parameter space and fitting models to data are clearly needed. This paper describes techniques for computing periodic orbits in systems of hybrid differential-algebraic equations and parameter estimation methods for fitting these orbits to data. These techniques make extensive use of automatic differentiation to accurately and efficiently evaluate derivatives for time integration, parameter sensitivities, root finding and optimization. The boundary value problem representing a periodic orbit in a hybrid system of differential algebraic equations is discretized via multiple-shooting using a high-degree Taylor series integration method (GM00, Phi03). Numerical solutions to the shooting equations are then estimated by a Newton process yielding an approximate periodic orbit. A metric is defined for computing the distance
Periodic orbits of hybrid systems and parameter estimation via AD.
Energy Technology Data Exchange (ETDEWEB)
Guckenheimer, John. (Cornell University); Phipps, Eric Todd; Casey, Richard (INRIA Sophia-Antipolis)
2004-07-01
Rhythmic, periodic processes are ubiquitous in biological systems; for example, the heart beat, walking, circadian rhythms and the menstrual cycle. Modeling these processes with high fidelity as periodic orbits of dynamical systems is challenging because: (1) (most) nonlinear differential equations can only be solved numerically; (2) accurate computation requires solving boundary value problems; (3) many problems and solutions are only piecewise smooth; (4) many problems require solving differential-algebraic equations; (5) sensitivity information for parameter dependence of solutions requires solving variational equations; and (6) truncation errors in numerical integration degrade performance of optimization methods for parameter estimation. In addition, mathematical models of biological processes frequently contain many poorly-known parameters, and the problems associated with this impedes the construction of detailed, high-fidelity models. Modelers are often faced with the difficult problem of using simulations of a nonlinear model, with complex dynamics and many parameters, to match experimental data. Improved computational tools for exploring parameter space and fitting models to data are clearly needed. This paper describes techniques for computing periodic orbits in systems of hybrid differential-algebraic equations and parameter estimation methods for fitting these orbits to data. These techniques make extensive use of automatic differentiation to accurately and efficiently evaluate derivatives for time integration, parameter sensitivities, root finding and optimization. The boundary value problem representing a periodic orbit in a hybrid system of differential algebraic equations is discretized via multiple-shooting using a high-degree Taylor series integration method [GM00, Phi03]. Numerical solutions to the shooting equations are then estimated by a Newton process yielding an approximate periodic orbit. A metric is defined for computing the distance
Vibration isolation of automotive vehicle engine using periodic mounting systems
Asiri, S.
2005-05-01
Customer awareness and sensitivity to noise and vibration levels have been raised through increasing television advertisement, in which the vehicle noise and vibration performance is used as the main market differentiation. This awareness has caused the transportation industry to regard noise and vibration as important criteria for improving market shares. One industry that tends to be in the forefront of the technology to reduce the levels of noise and vibration is the automobile industry. Hence, it is of practical interest to reduce the vibrations induced structural responses. The automotive vehicle engine is the main source of mechanical vibrations of automobiles. The engine is vulnerable to the dynamic action caused by engine disturbance force in various speed ranges. The vibrations of the automotive vehicle engines may cause structural failure, malfunction of other parts, or discomfort to passengers because of high level noise and vibrations. The mounts of the engines act as the transmission paths of the vibrations transmitted from the excitation sources to the body of the vehicle and passengers. Therefore, proper design and control of these mounts are essential to the attenuation of the vibration of platform structures. To improve vibration resistant capacities of engine mounting systems, vibration control techniques may be used. For instance, some passive and semi-active dissipation devices may be installed at mounts to enhance vibration energy absorbing capacity. In the proposed study, a radically different concept is presented whereby periodic mounts are considered because these mounts exhibit unique dynamic characteristics that make them act as mechanical filters for wave propagation. As a result, waves can propagate along the periodic mounts only within specific frequency bands called the "Pass Bands" and wave propagation is completely blocked within other frequency bands called the "Stop Bands". The experimental arrangements, including the design of
Stability Analysis for Multi-Parameter Linear Periodic Systems
DEFF Research Database (Denmark)
Seyranian, A.P.; Solem, Frederik; Pedersen, Pauli
1999-01-01
This paper is devoted to stability analysis of general linear periodic systems depending on real parameters. The Floquet method and perturbation technique are the basis of the development. We start out with the first and higher-order derivatives of the Floquet matrix with respect to problem...... parameters. Then the behaviour of simple and multiple multipliers of the system with a change of parameters is studied. Weak and strong interactions of multipliers in the complex plane are treated separately. The presented theory is exemplified and discussed....
Driven nonequilibrium lattice systems with shifted periodic boundary conditions
Energy Technology Data Exchange (ETDEWEB)
Valles, J.L. (New York Univ., NY (USA)); Leung, K.; Zia, R.K.P. (Virginia Polytechnic Institute and State Univ., Blacksburg (USA))
1989-07-01
The authors present the first study of a driven nonequilibrium lattice system in the two-phase region, with shifted periodic boundary conditions, forcing steps into the interface. When the shift corresponds to small angles with respect to the driving field, they find nonanalytic behavior in the (internal) energy of the system, supporting numerical evidence that interface roughness is suppressed by the field. For larger shifts, the competition between the driving field and the boundary induces the breakup of a single strip with tilted interfaces into many narrower strips with aligned interfaces. The size and temperature dependences of the critical angles of such breakup transitions are studied.
Periodically driven ergodic and many-body localized quantum systems
International Nuclear Information System (INIS)
We study dynamics of isolated quantum many-body systems whose Hamiltonian is switched between two different operators periodically in time. The eigenvalue problem of the associated Floquet operator maps onto an effective hopping problem. Using the effective model, we establish conditions on the spectral properties of the two Hamiltonians for the system to localize in energy space. We find that ergodic systems always delocalize in energy space and heat up to infinite temperature, for both local and global driving. In contrast, many-body localized systems with quenched disorder remain localized at finite energy. We support our conclusions by numerical simulations of disordered spin chains. We argue that our results hold for general driving protocols, and discuss their experimental implications
Periodically driven ergodic and many-body localized quantum systems
Energy Technology Data Exchange (ETDEWEB)
Ponte, Pedro [Perimeter Institute for Theoretical Physics, Waterloo, ON N2L 2Y5 (Canada); Department of Physics and Astronomy, University of Waterloo, ON N2L 3G1 (Canada); Chandran, Anushya [Perimeter Institute for Theoretical Physics, Waterloo, ON N2L 2Y5 (Canada); Papić, Z., E-mail: zpapic@perimeterinstitute.ca [Perimeter Institute for Theoretical Physics, Waterloo, ON N2L 2Y5 (Canada); Institute for Quantum Computing, Waterloo, ON N2L 3G1 (Canada); Abanin, Dmitry A. [Perimeter Institute for Theoretical Physics, Waterloo, ON N2L 2Y5 (Canada); Institute for Quantum Computing, Waterloo, ON N2L 3G1 (Canada)
2015-02-15
We study dynamics of isolated quantum many-body systems whose Hamiltonian is switched between two different operators periodically in time. The eigenvalue problem of the associated Floquet operator maps onto an effective hopping problem. Using the effective model, we establish conditions on the spectral properties of the two Hamiltonians for the system to localize in energy space. We find that ergodic systems always delocalize in energy space and heat up to infinite temperature, for both local and global driving. In contrast, many-body localized systems with quenched disorder remain localized at finite energy. We support our conclusions by numerical simulations of disordered spin chains. We argue that our results hold for general driving protocols, and discuss their experimental implications.
Dimension Reduction Near Periodic Orbits of Hybrid Systems
Burden, Samuel; Sastry, S Shankar
2011-01-01
When the Poincar\\'{e} map associated with a periodic orbit of a hybrid dynamical system has constant-rank iterates, we demonstrate the existence of a constant-dimensional invariant subsystem near the orbit which attracts all nearby trajectories in finite time. This result shows that the long-term behavior of a hybrid model with a large number of degrees-of-freedom may be governed by a low-dimensional smooth dynamical system. The appearance of such simplified models enables the translation of analytical tools from smooth systems-such as Floquet theory-to the hybrid setting and provides a bridge between the efforts of biologists and engineers studying legged locomotion.
Directory of Open Access Journals (Sweden)
Zijian Liu
2015-01-01
Full Text Available We study a two-patch impulsive migration periodic N-species Lotka-Volterra competitive system. Based on analysis method, inequality estimation, and Lyapunov function method, sufficient conditions for the permanence and existence of a unique globally stable positive periodic solution of the system are established. Some numerical examples are shown to verify our results and discuss the model further.
Rotational mixing in massive binaries: detached short-period systems
de Mink, S E; Langer, N; Pols, O R; Brott, I; Yoon, S -Ch
2009-01-01
Models of rotating single stars can successfully account for a wide variety of observed stellar phenomena, such as the surface enhancements of N and He. However, recent observations have questioned the idea that rotational mixing is the main process responsible for the surface enhancements, emphasizing the need for a strong and conclusive test. We investigate the consequences of rotational mixing for massive main-sequence stars in short-period binaries. In these systems the tides spin up the stars to rapid rotation. We use a state-of-the-art stellar evolution code including the effect of rotational mixing, tides, and magnetic fields. We discuss the surface abundances expected in massive close binaries (M1~20 solar masses) and we propose using such systems to test the concept of rotational mixing. As these short-period binaries often show eclipses, their parameters can be determined with high accuracy, allowing for a direct comparison with binary evolution models. In more massive close systems (M1~50 solar mas...
Semiclassical quantization of nonadiabatic systems with hopping periodic orbits
Energy Technology Data Exchange (ETDEWEB)
Fujii, Mikiya, E-mail: mikiya.fujii@gmail.com; Yamashita, Koichi [Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Tokyo 113-8656 (Japan); JST, CREST, Tokyo 113-8656 (Japan)
2015-02-21
We present a semiclassical quantization condition, i.e., quantum–classical correspondence, for steady states of nonadiabatic systems consisting of fast and slow degrees of freedom (DOFs) by extending Gutzwiller’s trace formula to a nonadiabatic form. The quantum–classical correspondence indicates that a set of primitive hopping periodic orbits, which are invariant under time evolution in the phase space of the slow DOF, should be quantized. The semiclassical quantization is then applied to a simple nonadiabatic model and accurately reproduces exact quantum energy levels. In addition to the semiclassical quantization condition, we also discuss chaotic dynamics involved in the classical limit of nonadiabatic dynamics.
Semiclassical quantization of nonadiabatic systems with hopping periodic orbits
Fujii, Mikiya; Yamashita, Koichi
2015-02-01
We present a semiclassical quantization condition, i.e., quantum-classical correspondence, for steady states of nonadiabatic systems consisting of fast and slow degrees of freedom (DOFs) by extending Gutzwiller's trace formula to a nonadiabatic form. The quantum-classical correspondence indicates that a set of primitive hopping periodic orbits, which are invariant under time evolution in the phase space of the slow DOF, should be quantized. The semiclassical quantization is then applied to a simple nonadiabatic model and accurately reproduces exact quantum energy levels. In addition to the semiclassical quantization condition, we also discuss chaotic dynamics involved in the classical limit of nonadiabatic dynamics.
Non-dispersive wave packets in periodically driven quantum systems
Buchleitner, A; Zakrzewski, J; Buchleitner, Andreas; Delande, Dominique; Zakrzewski, Jakub
2002-01-01
With the exception of the harmonic oscillator, quantum wave-packets usually spread as time evolves. We show here that, using the nonlinear resonance between an internal frequency of a system and an external periodic driving, it is possible to overcome this spreading and build non-dispersive (or non-spreading) wave-packets which are well localized and follow a classical periodic orbit without spreading. From the quantum mechanical point of view, the non-dispersive wave-packets are time periodic eigenstates of the Floquet Hamiltonian, localized in the nonlinear resonance island. We discuss the general mechanism which produces the non-dispersive wave-packets, with emphasis on simple realization in the electronic motion of a Rydberg electron driven by a microwave field. We show the robustness of such wavepackets for a model one-dimensional as well as for realistic three dimensional atoms. We consider their essential properties such as the stability versus ionization, the characteristic energy spectrum and long li...
Characterizing the Period Ratio Distribution of Kepler Exoplanetary Systems
Conaway, James L.; Ragozzine, Darin
2016-01-01
Many of the exoplanetary systems discovered by the Kepler space telescope demonstrate unusual properties which need to be explored in order to better understand planetary system formation and evolution. Among these interesting properties is an excess in the number of planets orbiting in resonance or near-resonance with their neighbors. The prevailing assumption in the planetary sciences community is that these are real features of the exoplanet population, but many theories developed on this assumption produce a resonance structure quite different from what we see. In our work we explore the possibility that the actual resonances may not be as we observe them, and may instead be explained by a combination of real resonance features and/or observational bias resulting from geometric effects. In particular, if the near-resonant systems have a different inclination distribution than other systems, then it is possible for them to be over or under-represented.We analyze the existing Kepler data and generate models which approximately represent the empirical period ratio distribution. The 2:1 and 3:2 just-wide-of-resonance excesses are included in the model, along with the deficit of period ratios just short of the 2:1 resonance. We test the Kepler data set against these models using the Python emcee package in order to determine the best-fit parameters for each model. We then address the inclination distribution question by generating two-planet systems with different inclination distributions for the near-resonant systems. We use the CORBITS package (https://github.com/jbrakensiek/CORBITS, Brakensiek & Ragozzine, submitted) to determine the probability of detecting both planets in transit. These tests adjust the relative sizes of the resonance excesses as well as orbital parameters (primarily inclination and nodal alignments) in order to determine which combinations of parameters would create in an observational bias resulting in the resonance excesses seen in the
Zhao, Guangyu; Ruan, Shigui
2011-06-01
We study the existence, uniqueness, and asymptotic stability of time periodic traveling wave solutions to a periodic diffusive Lotka-Volterra competition system. Under certain conditions, we prove that there exists a maximal wave speed c(*) such that for each wave speed c ≤ c(*), there is a time periodic traveling wave connecting two semi-trivial periodic solutions of the corresponding kinetic system. It is shown that such a traveling wave is unique modulo translation and is monotone with respect to its co-moving frame coordinate. We also show that the traveling wave solutions with wave speed c c(*).
Wide aperture periodic lens system for multiple Compton backscattering
Miyahara, Y
2002-01-01
Polarized gamma-ray generation by Compton backscattering in a periodic focusing system of electron and laser beams is discussed for the production of polarized positron beam in a linear collider. Circularly polarized CO sub 2 laser beams are focused by an optical lens series and collided with a 5.8 GeV electron beam to generate circularly polarized gamma-rays with 60 MeV at a maximum. In the present work, the basic concept of periodic lens system discussed previously is reconsidered to reduce the laser power required for a gamma-ray yield of 7x10 sup 1 sup 5 gamma/s and the peak laser power density at lenses as much as possible for technical practice. The electron beam is focused by a series of permanent quadrupole magnets with a FODO structure. The power is reduced to six sources with 5.6 kW each, and the peak power density is reduced to 1.4 GW/cm sup 2. These values can be reduced further by using a longer laser pulse length and a damping ring for the electron beam.
Institute of Scientific and Technical Information of China (English)
Jing HUI; Lan Sun CHEN
2004-01-01
The general system of differential equations describing predator-prey dynamics with impulsive effects is modified by the assumption that the coefficients are periodic functions of time. By use of standard techniques of bifurcation theory, it is known that this system has a positive periodic solution provided the time average of the predator's net uninhibited death rate is in a suitable range.The bifurcation is from the periodic solution of the time-dependent logistic equation for the prey (which results in the absence of predator).
Period of K system generator of pseudorandom numbers
Akopov, N Z; Floratos, Emmanuel G; Savvidy, G K
1996-01-01
We analyze the structure of the periodic trajectories of the matrix generator of pseudorandom numbers which has been proposed earlier. The structure of the periodic trajectories becomes more transparent when the rational sublattice coincides with the Galois field GF[p]. We are able to compute the period of the trajectories as a function of p and the dimension of the matrix d.
Directory of Open Access Journals (Sweden)
Khazan A.
2011-01-01
Full Text Available In the earlier study (Khazan A. Upper Limit in Mendeleev's Periodic Table - Element No.155. 2nd ed., Svenska fysikarkivet, Stockholm, 2010 the author showed how Rhodium can be applied to the hyperbolic law of the Periodic Table of Elements in order to calculate, with high precision, all other elements conceivable in the Table. Here we obtain the same result, with use of fraction linear functions (adjacent hyperbolas.
Woo, K. S.; Ji, H. S.; Nam, S.; Stein, R. H.; Mackensen, A.; Matthiessen, J. J.
2013-12-01
Carbonate minerals were discovered from the giant box core (PS72/410-1) of the pelagic sediments recovered from the Canadian Arctic across the central Mendeleev Ridge (Station location= Lat. 80°30.37"N, Long. 175°44.38"W) during the Arctic cruise by Polarstern in 2008. The core was 39 cm long and was collected from the water depth of 1802 meters. The sediments show various colours from grey to brown as previously reported in other Arctic pelagic sediments. The sediments include planktonic foraminifers together with carbonate minerals. The contents of planktonic foraminifers and carbonate minerals vary with core depth, however these carbonate minerals are present through the whole sequence except for a few centimetres. After wet sieving, coarse fractions were texturally examined with binocular microscope and SEM, and stable isotope and trace element contents were obtained. Mineralogy of carbonate minerals were determined using crystal shapes and qualitative Sr contents by EDAX together with trace element analysis. The carbonates are composed of high Mg-calcite, low Mg-calcite and aragonite. Aragonite crystals show (1) radiating fibrous texture, (2) randomly oriented fibrous texture, (3) spherulitic fibrous texture, and (4) bladed texture, and calcite crystals show (1) foliated texture, (2) randomly bladed texture, (3) spherulitic fibrous texture, and (4) equant texture. Various crystal shapes of aragonite and calcite together with clear growth shapes of the crystals suggest that they are inorganic in origin. Highly enriched carbon isotope compositions (δ13C = 0 ~ +5‰ vs. PDB) strongly indicate that they formed in methanogenic zone below sediment/water interface by the reaction between anoxic pore fluids and host sediments induced by methanogenic bacteria. However, a wide range of oxygen isotope values (δ18O = -5 ~ +5‰ vs. PDB) may indicate that porewater has been changed due to reaction between residual seawater and volcanic sediments. Four types of stable
Nam, Seung-Il; Woo, Kyung Sik; Ji, Hyo Seon; Stein, Ruediger; Mackensen, Andreas; Matthiessen, Jens
2015-04-01
Authigenic carbonates and mud fractions of the glaciomarine sediments were investigated texturally and geochemically. The sediment core (PS72/410-1) was retrieved using a giant box corer from the central Mendeleev Ridge of the western Arctic Ocean (Station location= Lat. 80°30.37"N, Long. 175°44.38"W) during the Polarstern Arctic expedition (PS72) in 2008. The core is 39 cm long with age of ca. 76 ka BP and was collected from the water depth of 1,802 meters. The sediments show various colours from grey to brown as previously reported in other Arctic deep sea sediments, reflecting glacial-interglacial and/or stadial-interstadial cycles. Authigenic carbonate minerals are present through the whole sequence except for a few centimetres. These authigenic carbonates are composed of high Mg-calcite, low Mg-calcite and aragonite. Various crystal shapes of aragonite and calcite together with clear growth shapes of the crystals suggest that they are inorganic in origin. Highly enriched carbon isotope compositions (δ13C = 0 ~ +5‰ vs. PDB) strongly indicate that they formed in methanogenic zone below sediment/water interface by the reaction between anoxic pore fluids and host sediments induced by methanogenic bacteria. However, a wide range of oxygen isotope values (δ18O = -5 ~ +5‰ vs. PDB) may indicate that porewater has been changed due to reaction between residual seawater and volcanic sediments. Relatively higher contents of K, Al, Fe and Be values from muddy sediments as well as low δ18O compositions of authigenic carbonates may imply strong input of meltwater from volcanic region (Eastern Arctic region) whereas higher oxygen isotope compositions of authigenic carbonates and higher Sr and K contents of mud sediments may reflect stronger influence from carbonate-rich region (Canadian Arctic region). Mineralogical changes form low to high Mg-calcite together with decrease in Mg, Sr and Fe contents strongly support less freshwater input from glacial mode to
Directory of Open Access Journals (Sweden)
Dhaou Lassoued
2013-04-01
Full Text Available We prove that a family of $q$-periodic continuous matrix valued function ${A(t}_{tin mathbb{R}}$ has an exponential dichotomy with a projector $P$ if and only if $int_0^t e^{imu s}U(t,sPds$ is bounded uniformly with respect to the parameter $mu$ and the solution of the Cauchy operator Problem $$displaylines{ dot{Y}(t=-Y(tA(t+ e^{i mu t}(I-P ,quad tgeq s cr Y(s=0, }$$ has a limit in $mathcal{L}(mathbb{C}^n$ as s tends to $-infty$ which is bounded uniformly with respect to the parameter $mu$. Here, ${ U(t,s: t, sinmathbb{R}}$ is the evolution family generated by ${A(t}_{tin mathbb{R}}$, $mu$ is a real number and q is a fixed positive number.
Analysis of the Mode of the Periodically Time-varying Vibration Systems
Institute of Scientific and Technical Information of China (English)
WANG Sheng-ze; REN Ji-ge
2007-01-01
By Liapunov reducibility theorem, the periodically time-varying vibration system can be transformed to a linear time-invariant system. Based on the dynamic characteristics of the linear time-invariant system, the mode of the periodically time-varying vibration system has been discussed. The paper defines the mode and analyzes its characteristics. It can be found that the mode of the periodically time-varying system is periodically time-varing but has such characteristics as orthogonality. Finally, a method is given to solve the mode. By solving the eigenvalues and the eigenvectors of the state transition matrix in one period, the periodically time-varying mode can be obtained.
Molecular Dynamics ofa Coulomb System with Deformable Periodic Boundary Conditions
Totsuji, Hiroo; Shirokoshi, Hideki; Nara, Shigetoshi
1991-01-01
Variable shape molecular dynamics is formulated for the one-component plasma and the structural transition from the fcc lattice to the bcc lattice has been observed. It is emphasized that the condition of constant volume should be imposed when deformations of periodic boundary conditions are taken into account.
Emergence of spike correlations in periodically forced excitable systems
Reinoso, José A.; Torrent, M. C.; Masoller, Cristina
2016-09-01
In sensory neurons the presence of noise can facilitate the detection of weak information-carrying signals, which are encoded and transmitted via correlated sequences of spikes. Here we investigate the relative temporal order in spike sequences induced by a subthreshold periodic input in the presence of white Gaussian noise. To simulate the spikes, we use the FitzHugh-Nagumo model and to investigate the output sequence of interspike intervals (ISIs), we use the symbolic method of ordinal analysis. We find different types of relative temporal order in the form of preferred ordinal patterns that depend on both the strength of the noise and the period of the input signal. We also demonstrate a resonancelike behavior, as certain periods and noise levels enhance temporal ordering in the ISI sequence, maximizing the probability of the preferred patterns. Our findings could be relevant for understanding the mechanisms underlying temporal coding, by which single sensory neurons represent in spike sequences the information about weak periodic stimuli.
Dynamical System Approach to a Coupled Dispersionless System: Localized and Periodic Traveling Waves
Institute of Scientific and Technical Information of China (English)
Gambo Betchewe; Kuetche Kamgang Victor; Bouetou Bouetou Thomas; Timoleon Crepin Kofane
2009-01-01
We investigate the dynamical behavior of a coupled dispersionlees system describing a current-conducting string with infinite length within a magnetic field.Thus,following a dynamical system approach,we unwrap typical miscellaneous traveling waves including localized and periodic ones.Studying the relative stabilities of such structures through their energy densities,we find that under some boundary conditions,localized waves moving in positive directions are more stable than periodic waves which in contrast stand for the most stable traveling waves in another boundary condition situation.
Wiediger, Susan D.
2009-01-01
The periodic table and the periodic system are central to chemistry and thus to many introductory chemistry courses. A number of existing activities use various data sets to model the development process for the periodic table. This paper describes an image arrangement computer program developed to mimic a paper-based card sorting periodic table…
Chaos in periodically forced Holling type IV predator-prey system with impulsive perturbations
International Nuclear Information System (INIS)
The effect of periodic forcing and impulsive perturbations on predator-prey model with Holling type IV functional response is investigated. The periodic forcing is affected by assuming a periodic variation in the intrinsic growth rate of the prey. The impulsive perturbations are affected by introducing periodic constant impulsive immigration of predator. The dynamical behavior of the system is simulated and bifurcation diagrams are obtained for different parameters. The results show that periodic forcing and impulsive perturbation can easily give rise to complex dynamics, including (1) quasi-periodic oscillating, (2) period doubling cascade, (3) chaos, (4) period halfing cascade
Chaos in periodically forced Holling type II predator-prey system with impulsive perturbations
International Nuclear Information System (INIS)
The effect of periodic forcing and impulsive perturbations on predator-prey model with Holling type II functional response is investigated. The periodic forcing is affected by assuming a periodic variation in the intrinsic growth rate of prey. The impulsive perturbation is affected by introducing periodic constant impulsive immigration of predator. The dynamical behavior of the system is simulated and bifurcation diagrams are obtained for different parameters. The results show that periodic forcing and impulsive perturbation can very easily give rise to complex dynamics, including (1) quasi-periodic oscillating, (2) period doubling cascade, (3) chaos, (4) period halfing cascade, (5) non-unique dynamics
On-Iine Management System for the Periodicals in JAERl
Itabashi, Keizo; Mineo, Yukinobu
The article describes the outlines of the on-line serials control system utilizing a mini-computer. The system is dealt with subscription, check-in, claiming, inquiry of serials information and binding of journals. In this system journal acquisition with serial arrival prediction in an on-line mode is carried on a priority principle to record the actual receipt of incoming issues.
Positive periodic solutions for a neutral Lotka-Volterra system with state dependent delays
Li, Yongkun; Zhao, Lili
2009-04-01
By using a fixed point theorem of strict-set-contraction, some new criteria are established for the existence of positive periodic solutions of the following periodic neutral Lotka-Volterra system with state dependent delays
NUMERICALLY SOLVING PERIODICALLY PERTURBED CONSERVATIVE SYSTEMS BY PARAMETER EMBEDDING METHODS
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The parameter embedding method is applied for numerically solving the perturbed conservative systems. By means of Newtonian iteration, a simple algorithm has been constructed. Finally, the convergence of the iteration is proved.
Enhancing Quantum Effects via Periodic Modulations in Optomechanical Systems
Farace, Alessandro; Giovannetti, Vittorio
2012-01-01
Parametrically modulated optomechanical systems have been recently proposed as a simple and efficient setting for the quantum control of a micromechanical oscillator: relevant possibilities include the generation of squeezing in the oscillator position (or momentum) and the enhancement of entanglement between mechanical and radiation modes. In this paper we further investigate this new modulation regime, considering an optomechanical system with one or more parameters being modulated over tim...
BIFURCATION OF PERIODIC ORBITS OF A THREE-DIMENSIONAL SYSTEM
Institute of Scientific and Technical Information of China (English)
LIU XUANLIANG; HAN MAOAN
2005-01-01
Consider a three-dimensional system having an invariant surface. By using bifurcation techniques and analyzing the solutions of bifurcation equations, the authors study the spacial bifurcation phenomena of a k multiple closed orbit in the invariant surface.The sufficient conditions of the existence of many closed orbits bifurcate from the k multiple closed orbit are obtained.
Portable system for periodical verification of area monitors for neutrons
International Nuclear Information System (INIS)
The Neutrons Laboratory develops a project viewing the construction of a portable test system for verification of functioning conditions of neutron area monitors. This device will allow to the users the verification of the calibration maintenance of his instruments at the use installations, avoiding the use of an inadequate equipment related to his answer to the neutron beam response
The periodic table: icon and inspiration.
Poliakoff, Martyn; Tang, Samantha
2015-03-13
To start this discussion meeting on the new chemistry of the elements held on 12 May 2014, Martyn Poliakoff, Foreign Secretary of the Royal Society, was invited to give the opening remarks. As a chemist and a presenter of the popular online video channel 'The periodic table of videos', Martyn communicates his personal and professional interest in the elements to the public, who in turn use these videos both as an educational resource and for entertainment purposes. Ever since Mendeleev's first ideas for the periodic table were published in 1869, the table has continued to grow as new elements have been discovered, and it serves as both icon and inspiration; its form is now so well established that it is recognized the world over as a symbol for science. This paper highlights but a few of the varied forms that the table can take, such as an infographic, which can convey the shortage of certain elements with great impact. PMID:25666072
Linear Impulsive Periodic System with Time-Varying Generating Operators on Banach Space
Directory of Open Access Journals (Sweden)
Wei W
2007-01-01
Full Text Available A class of the linear impulsive periodic system with time-varying generating operators on Banach space is considered. By constructing the impulsive evolution operator, the existence of -periodic -mild solution for homogeneous linear impulsive periodic system with time-varying generating operators is reduced to the existence of fixed point for a suitable operator. Further the alternative results on -periodic -mild solution for nonhomogeneous linear impulsive periodic system with time-varying generating operators are established and the relationship between the boundness of solution and the existence of -periodic -mild solution is shown. The impulsive periodic motion controllers that are robust to parameter drift are designed for a given periodic motion. An example given for demonstration.
Enhancing Quantum Effects via Periodic Modulations in Optomechanical Systems
Farace, Alessandro
2012-01-01
Parametrically modulated optomechanical systems have been recently proposed as a simple and efficient setting for the quantum control of a micromechanical oscillator: relevant possibilities include the generation of squeezing in the oscillator position (or momentum) and the enhancement of entanglement between mechanical and radiation modes. In this paper we further investigate this new modulation regime, considering an optomechanical system with one or more parameters being modulated over time. We first apply a sinusoidal modulation of the mechanical frequency and characterize the optimal regime in which the visibility of purely quantum effects is maximal. We then introduce a second modulation on the input laser intensity and analyze the interplay between the two. We find that an interference pattern shows up, so that different choices of the relative phase between the two modulations can either enhance or cancel the desired quantum effects.
Enhancing quantum effects via periodic modulations in optomechanical systems
Farace, Alessandro; Giovannetti, Vittorio
2012-07-01
Parametrically modulated optomechanical systems have been recently proposed as a simple and efficient setting for the quantum control of a micromechanical oscillator: relevant possibilities include the generation of squeezing in the oscillator position (or momentum) and the enhancement of entanglement between mechanical and radiation modes. In this paper we further investigate this modulation regime, considering an optomechanical system with one or more parameters being modulated over time. We first apply a sinusoidal modulation of the mechanical frequency and characterize the optimal regime in which the visibility of purely quantum effects is maximal. We then introduce a second modulation on the input laser intensity and analyze the interplay between the two. We find that an interference pattern shows up, so that different choices of the relative phase between the two modulations can either enhance or cancel the desired quantum effects, opening new possibilities for optimal quantum control strategies.
P Systems Computing the Period of Irreducible Markov Chains
Cardona Roca, Mónica; Colomer Cugat, M. Angeles; Riscos Núñez, Agustín; Rius Font, Miquel
2009-01-01
It is well known that any irreducible and aperiodic Markov chain has exactly one stationary distribution, and for any arbitrary initial distribution, the sequence of distributions at time n converges to the stationary distribution, that is, the Markov chain is approaching equilibrium as n→∞. In this paper, a characterization of the aperiodicity in existential terms of some state is given. At the same time, a P system with external output is associated with any irreducible Ma...
Periodic inspection for safety of CANDU heat transport piping systems
International Nuclear Information System (INIS)
An approach has been developed for the prediction of the risk of failure or the survival of heat transport piping systems in a nuclear power plant. The effects of various inspection schemes on the risk of failure have been investigated and an inspection method proposed. A list of input data required to apply this method to real situations is specified. Using an example of a pressurized pipe containing a defect, it is shown that the required data can be obtained easily
Quantum mechanics of rapidly and periodically driven systems
Indian Academy of Sciences (India)
Malay Bandyopadhyay; Sushanta Dattagupta
2008-03-01
This review deals with the dynamics of quantum systems that are subject to high frequency external perturbations. Though the problem may look hopelessly time-dependent, and poised on the extreme opposite side of adiabaticity, there exists a `Kapitza Window' over which the dynamics can be treated in terms of effective time-independent Hamiltonians. The consequent results are important in the context of atomic traps as well as quantum optic properties of atoms in intense and high-frequency electromagnetic fields.
Optoelectronic timing system. Period covered: April--June 1976
Energy Technology Data Exchange (ETDEWEB)
Hanes, L.D.
1976-01-01
An optoelectronic timing system is being developed for the measurement of detonation front arrival times in an initiation sensitivity test currently in use at Pantex. The primary goal this quarter was the design, construction, and testing of a photodiode circuit which would have a two-nanosecond rise time response proportional to light intensity and which would have an adequate voltage output for the level of light intensity encountered in the sensitivity test. The results were satisfactory.
Directory of Open Access Journals (Sweden)
Zheyan Zhou
2011-01-01
Full Text Available We propose a discrete multispecies cooperation and competition predator-prey systems. For general nonautonomous case, sufficient conditions which ensure the permanence and the global stability of the system are obtained; for periodic case, sufficient conditions which ensure the existence of a globally stable positive periodic solution of the system are obtained.
45 CFR 1386.23 - Periodic reports: Protection and Advocacy System.
2010-10-01
... 45 Public Welfare 4 2010-10-01 2010-10-01 false Periodic reports: Protection and Advocacy System... Advocacy of the Rights of Individuals with Developmental Disabilities § 1386.23 Periodic reports: Protection and Advocacy System. (a) By January 1 of each year the Protection and Advocacy System shall...
Feng Cao; Yelai Fu
2014-01-01
In this article, we study the asymptotic dynamics in nonmonotone comparable almost periodic reaction-diffusion systems with Dirichlet boundary condition, which are comparable with uniformly stable strongly order-preserving system. By appealing to the theory of skew-product semiflows, we obtain the asymptotic almost periodicity of uniformly stable solutions to the comparable reaction-diffusion system.
Directory of Open Access Journals (Sweden)
Feng Cao
2014-04-01
Full Text Available In this article, we study the asymptotic dynamics in nonmonotone comparable almost periodic reaction-diffusion systems with Dirichlet boundary condition, which are comparable with uniformly stable strongly order-preserving system. By appealing to the theory of skew-product semiflows, we obtain the asymptotic almost periodicity of uniformly stable solutions to the comparable reaction-diffusion system.
Global Analysis of Almost Periodic Solution of a Discrete Multispecies Mutualism System
Directory of Open Access Journals (Sweden)
Hui Zhang
2014-01-01
of the system. Assuming that the coefficients in the system are almost periodic sequences, we obtain the sufficient conditions for the existence of a unique almost periodic solution which is globally attractive. In particular, for the discrete two-species Lotka-Volterra mutualism system, the sufficient conditions for the existence of a unique uniformly asymptotically stable almost periodic solution are obtained. An example together with numerical simulation indicates the feasibility of the main result.
Institute of Scientific and Technical Information of China (English)
LuoGuanwei; XieJianhua
2003-01-01
A two-degrees-of-freedom vibratory system with a clearance or gap is under consideration based on the Poincard map. Stability and local bifurcation of the period-one doubleimpact symmetrical motion of the system are analyzed by using the equation of map. The routes from periodic impact motions to chaos, via pitchfork bifurcation, period-doubling bifurcation and grazing bifurcation, are studied by numerical simulation. Under suitable system parameter conditions, Neimark-Sacker bifurcations associated with periodic impact motion can occur in the two-degrees-of-freedom vibro-impact system.
Shimeld, John; Li, Qingmou; Chian, Deping; Lebedeva-Ivanova, Nina; Jackson, Ruth; Mosher, David; Hutchinson, Deborah R.
2016-01-01
The Canada Basin and the southern Alpha-Mendeleev ridge complex underlie a significant proportion of the Arctic Ocean, but the geology of this undrilled and mostly ice-covered frontier is poorly known. New information is encoded in seismic wide-angle reflections and refractions recorded with expendable sonobuoys between 2007 and 2011. Velocity–depth samples within the sedimentary succession are extracted from published analyses for 142 of these records obtained at irregularly spaced stations across an area of 1.9E + 06 km2. The samples are modelled at regional, subregional and station-specific scales using an exponential function of inverse velocity versus depth with regionally representative parameters determined through numerical regression. With this approach, smooth, non-oscillatory velocity–depth profiles can be generated for any desired location in the study area, even where the measurement density is low. Practical application is demonstrated with a map of sedimentary thickness, derived from seismic reflection horizons interpreted in the time domain and depth converted using the velocity–depth profiles for each seismic trace. A thickness of 12–13 km is present beneath both the upper Mackenzie fan and the middle slope off of Alaska, but the sedimentary prism thins more gradually outboard of the latter region. Mapping of the observed-to-predicted velocities reveals coherent geospatial trends associated with five subregions: the Mackenzie fan; the continental slopes beyond the Mackenzie fan; the abyssal plain; the southwestern Canada Basin; and, the Alpha-Mendeleev magnetic domain. Comparison of the subregional velocity–depth models with published borehole data, and interpretation of the station-specific best-fitting model parameters, suggests that sandstone is not a predominant lithology in any of the five subregions. However, the bulk sand-to-shale ratio likely increases towards the Mackenzie fan, and the model for this subregion compares
Shimeld, John; Li, Qingmou; Chian, Deping; Lebedeva-Ivanova, Nina; Jackson, Ruth; Mosher, David; Hutchinson, Deborah
2016-01-01
The Canada Basin and the southern Alpha-Mendeleev ridge complex underlie a significant proportion of the Arctic Ocean, but the geology of this undrilled and mostly ice-covered frontier is poorly known. New information is encoded in seismic wide-angle reflections and refractions recorded with expendable sonobuoys between 2007 and 2011. Velocity-depth samples within the sedimentary succession are extracted from published analyses for 142 of these records obtained at irregularly spaced stations across an area of 1.9E + 06 km2. The samples are modelled at regional, subregional and station-specific scales using an exponential function of inverse velocity versus depth with regionally representative parameters determined through numerical regression. With this approach, smooth, non-oscillatory velocity-depth profiles can be generated for any desired location in the study area, even where the measurement density is low. Practical application is demonstrated with a map of sedimentary thickness, derived from seismic reflection horizons interpreted in the time domain and depth converted using the velocity-depth profiles for each seismic trace. A thickness of 12-13 km is present beneath both the upper Mackenzie fan and the middle slope off of Alaska, but the sedimentary prism thins more gradually outboard of the latter region. Mapping of the observed-to-predicted velocities reveals coherent geospatial trends associated with five subregions: the Mackenzie fan; the continental slopes beyond the Mackenzie fan; the abyssal plain; the southwestern Canada Basin; and, the Alpha-Mendeleev magnetic domain. Comparison of the subregional velocity-depth models with published borehole data, and interpretation of the station-specific best-fitting model parameters, suggests that sandstone is not a predominant lithology in any of the five subregions. However, the bulk sand-to-shale ratio likely increases towards the Mackenzie fan, and the model for this subregion compares favourably with
Emergence of quasiperiodicity in symmetrically coupled, identical period-doubling systems
DEFF Research Database (Denmark)
Reick, Christian; Mosekilde, Erik
1995-01-01
When two Identical period-doubling systems are coupled symmetrically, the period-doubling transition to chaos may be replaced by a quasiperiodic transition. The reason for this is that at an early stage of the period-doubling cascade, a Hopf bifurcation instead of a period-doubling bifurcation...... occurs. Our main result is that the emergence of this Hopf bifurcation is a generic phenomenon in symmetrically coupled, identical period-doubling systems. The whole phenomenon is stable against small nonsymmetric perturbations. Our results cover maps and differential equations of arbitrary dimension...
Aeroelastic stability of periodic systems with application to rotor blade flutter
Friedmann, P.; Silverthorn, L. J.
1974-01-01
The dynamics of a helicopter blade in forward flight are described by a system of linear differential equations with periodic coefficients. The stability of this periodic aeroelastic system is determined, using multivariable Floquet-Liapunov theory. The transition matrix at the end of the period is evaluated by: (1) direct numerical integration, and (2) a new, approximate method, which consists in approximating a periodic function by a series of step functions. The numerical accuracy and efficiency of the methods is compared, and the second method is shown to be superior by far. Results illustrating the effect of the periodic coefficients and various blade parameters are presented.
Institute of Scientific and Technical Information of China (English)
WU Bo; CHEN Gang; JIANG Zhengfeng; ZHENG Junyi
2006-01-01
Approximate calculation methods of prevention maintenance period under the random distribution are given, and three kinds of approximate calculation models of prevention maintenance period based on different security demands are come up with according to maintenance problems of machinery systems in modern enterprise and starting with different demands of systems. And then, how to make certain the best maintenance period by using the approximate calculation methods is illustrated by an example.
On angular momentum balance for particle systems with periodic boundary conditions
Kuzkin, Vitaly A.
2013-01-01
The well-known issue with the absence of conservation of angular momentum in classical particle systems with periodic boundary conditions is addressed. It is shown that conventional theory based on Noether's theorem fails to explain the simplest possible example, notably jumps of angular momentum in the case of single particle moving in a periodic cell. It is suggested to consider the periodic cell as an open system, exchanging mass, momentum, angular momentum, and energy with surrounding cel...
Controlling chaos in a high dimensional system with periodic parametric perturbations
Energy Technology Data Exchange (ETDEWEB)
Mirus, K.A.; Sprott, J.C.
1998-10-01
The effect of applying a periodic perturbation to an accessible parameter of a high-dimensional (coupled-Lorenz) chaotic system is examined. Numerical results indicate that perturbation frequencies near the natural frequencies of the unstable periodic orbits of the chaotic system can result in limit cycles or significantly reduced dimension for relatively small perturbations.
Spiral organization of periodic structures in the Lorenz–Stenflo system
Rech, Paulo C.
2016-07-01
This paper reports the existence of organized periodic structures embedded in chaotic regions of a parameter plane of the Lorenz–Stenflo system. More specifically, this work reports on spiral organization of periodic structures observed in the (σ, s) parameter plane of the Lorenz–Stenflo system.
The virial theorem and exact properties of density functionals for periodic systems
Mirhosseini, H.; Cangi, A.; Baldsiefen, T.; Sanna, A.; Proetto, C. R.; Gross, E. K. U.
2014-01-01
In the framework of density functional theory, scaling and the virial theorem are essential tools for deriving exact properties of density functionals. Preexisting mathematical difficulties in deriving the virial theorem via scaling for periodic systems are resolved via a particular scaling technique. This methodology is employed to derive universal properties of the exchange-correlation energy functional for periodic systems.
PERMANENCE AND PERIODIC SOLUTION IN AN INTEGRODIFFERENTIAL SYSTEM WITH DISCRETE DIFFUSION
Institute of Scientific and Technical Information of China (English)
XIAO Yanni; CHEN Lansun; TANG Sanyi
2003-01-01
Dynamical characteristics of an integrodifferential modelling competitive sys-tem with diffusion are investigated. In particular, we derive sufficient conditions for thepermanence of species, existence of an attracting periodic solution to the periodic system.The results of Wang Ke in 1994 and 1998 are improved and extended.
Tropical Krichever construction for the non-periodic box and ball system
Iwao, Shinsuke; Isojima, Shin
2012-01-01
A solution for an initial value problem of the box and ball system is constructed from a solution of the periodic box and ball system. The construction is done through a specific limiting process based on the theory of tropical geometry. This method gives a tropical analogue of the Krichever construction, which is an algebro-geometric method to construct exact solutions to integrable systems, for the non-periodic system.
Responses of a Noisy Excitable System to External Signals with Different Periods
Institute of Scientific and Technical Information of China (English)
JIA Xun; ZHOU Lu-Qun; OUYANG Qi
2004-01-01
@@ The behaviour of an excitable system under Gaussian white noise and external periodic forcing is systematically studied. In a large range of noise intensity, the n:1 phase locking patterns are obtained for certain ranges of the input periods, where n input periods give one spike. In the phase locking regimes, the system presents low noise-to-signal ratios and shows better regularities. Out of the regimes the system behavesless regularly and the relations between the noise-to-signal ratio and the noise intensity exhibit typical stochastic resonance phenomena.At a higher noise level, the system shows the characteristic behaviour of the noise.
Double Grazing Periodic Motions and Bifurcations in a Vibroimpact System with Bilateral Stops
Directory of Open Access Journals (Sweden)
Qunhong Li
2014-01-01
Full Text Available The double grazing periodic motions and bifurcations are investigated for a two-degree-of-freedom vibroimpact system with symmetrical rigid stops in this paper. From the initial condition and periodicity, existence of the double grazing periodic motion of the system is discussed. Using the existence condition derived, a set of parameter values is found that generates a double grazing periodic motion in the considered system. By extending the discontinuity mapping of one constraint surface to that of two constraint surfaces, the Poincaré map of the vibroimpact system is constructed in the proximity of the grazing point of a double grazing periodic orbit, which has a more complex form than that of the single grazing periodic orbit. The grazing bifurcation of the system is analyzed through the Poincaré map with clearance as a bifurcation parameter. Numerical simulations show that there is a continuous transition from the chaotic band to a period-1 periodic motion, which is confirmed by the numerical simulation of the original system.
Periodic Solutions for n-Species Lotka-Volterra Competitive Systems with Pure Delays
Directory of Open Access Journals (Sweden)
Ahmadjan Muhammadhaji
2015-01-01
Full Text Available We study a class of periodic general n-species competitive Lotka-Volterra systems with pure delays. Based on the continuation theorem of the coincidence degree theory and Lyapunov functional, some new sufficient conditions on the existence and global attractivity of positive periodic solutions for the n-species competitive Lotka-Volterra systems are established. As an application, we also examine some special cases of the system, which have been studied extensively in the literature.
Controlling chaos in low and high dimensional systems with periodic parametric perturbations
Energy Technology Data Exchange (ETDEWEB)
Mirus, K.A.; Sprott, J.C.
1998-06-01
The effect of applying a periodic perturbation to an accessible parameter of various chaotic systems is examined. Numerical results indicate that perturbation frequencies near the natural frequencies of the unstable periodic orbits of the chaotic systems can result in limit cycles for relatively small perturbations. Such perturbations can also control or significantly reduce the dimension of high-dimensional systems. Initial application to the control of fluctuations in a prototypical magnetic fusion plasma device will be reviewed.
Chaotic Dynamics of One-Dimensional Systems with Periodic Boundary Conditions
Kumar, Pankaj; Miller, Bruce N.
2014-01-01
We provide appropriate tools for the analysis of dynamics and chaos for one-dimensional systems with periodic boundary conditions. Our approach allows for the investigation of the dependence of the largest Lyapunov exponent on various initial conditions of the system. The method employs an effective approach for defining the phase-space distance appropriate for systems with periodic boundary and allows for an unambiguous test-orbit rescaling in the phase space required to calculate the Lyapun...
Chaotic system for the detection of periodic signals under the background of strong noise
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
We propose a method to study the chaotic system for the detection of periodic signals in the presence of strong background noise. The numerical experiments indicate that the chaotic system constructed from the modified Duffing-Holmes equation is sensitive to the weak periodic signal mixed with noise, and it has certain immunity to noise. The signal to noise ratio for the system can reach to about -91 dB.
Immune system adaptations during competition period in female cross-country skiers
Stenholm, Johanna
2011-01-01
Stenholm, Johanna. Immune system adaptations during competition period in female cross-country skiers. Master’s Thesis in Exercise Physiology, Department of Biology of Physical Activity. University of Jyväskylä. 95pp. Purpose. This study was undertaken to characterize the extent of immune and endocrine changes in competition period and related to two competition weekends in well trained athletes in different parts of the competition period. An additional purpose was to evaluate if the cha...
Existence of Almost-Periodic Solutions for Lotka-Volterra Cooperative Systems with Time Delay
Directory of Open Access Journals (Sweden)
Kaihong Zhao
2012-01-01
Full Text Available This paper considers the existence of positive almost-periodic solutions for almost-periodic Lotka-Volterra cooperative system with time delay. By using Mawhin’s continuation theorem of coincidence degree theory, sufficient conditions for the existence of positive almost-periodic solutions are obtained. An example and its simulation figure are given to illustrate the effectiveness of our results.
Periodic Solutions of the 1D Vlasov-Maxwell System with Boundary Conditions
Bostan, Mihai
1998-01-01
We study the 1D Vlasov-Maxwell system with time periodic boundary conditions in its classical and relativistic form. For small data we prove existence of weak periodic solutions. It is necessary to impose non vanishing conditions for the incoming velocities in order to control the life-time of particles in the domain. In order to preserve the periodicity, another condition of vanishing the time average of the incoming current is imposed.
Dynamic behaviors of the periodic Lotka-Volterra competing system with impulsive perturbations
Energy Technology Data Exchange (ETDEWEB)
Liu Bing [Department of Mathematics, Anshan Normal University, Anshan 114005, Liaoning (China) and Department of Mathematics, Xinjiang University, Urumqi 830046, Xinjiang (China)]. E-mail: liubing529@126.com; Teng Zhidong [Department of Mathematics, Xinjiang University, Urumqi 830046, Xinjiang (China); Liu Wanbo [Senior Middle School of Anshan Steel-Iron Company, Anshan 114034, Liaoning (China)
2007-01-15
In this paper, we investigate a classical periodic Lotka-Volterra competing system with impulsive perturbations. The conditions for the linear stability of trivial periodic solution and semi-trivial periodic solutions are given by applying Floquet theory of linear periodic impulsive equation, and we also give the conditions for the global stability of these solutions as a consequence of some abstract monotone iterative schemes introduced in this paper, which will be also used to get some sufficient conditions for persistence. By using the method of coincidence degree, the conditions for the existence of at least one strictly positive (componentwise) periodic solution are derived. The theoretical results are confirmed by a specific example and numerical simulations. It shows that the dynamic behaviors of the system we consider are quite different from the corresponding system without pulses.
Self-similarities of periodic structures for a discrete model of a two-gene system
Energy Technology Data Exchange (ETDEWEB)
Souza, S.L.T. de, E-mail: thomaz@ufsj.edu.br [Departamento de Física e Matemática, Universidade Federal de São João del-Rei, Ouro Branco, MG (Brazil); Lima, A.A. [Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, MG (Brazil); Caldas, I.L. [Instituto de Física, Universidade de São Paulo, São Paulo, SP (Brazil); Medrano-T, R.O. [Departamento de Ciências Exatas e da Terra, Universidade Federal de São Paulo, Diadema, SP (Brazil); Guimarães-Filho, Z.O. [Aix-Marseille Univ., CNRS PIIM UMR6633, International Institute for Fusion Science, Marseille (France)
2012-03-12
We report self-similar properties of periodic structures remarkably organized in the two-parameter space for a two-gene system, described by two-dimensional symmetric map. The map consists of difference equations derived from the chemical reactions for gene expression and regulation. We characterize the system by using Lyapunov exponents and isoperiodic diagrams identifying periodic windows, denominated Arnold tongues and shrimp-shaped structures. Period-adding sequences are observed for both periodic windows. We also identify Fibonacci-type series and Golden ratio for Arnold tongues, and period multiple-of-three windows for shrimps. -- Highlights: ► The existence of noticeable periodic windows has been reported recently for several nonlinear systems. ► The periodic window distributions appear highly organized in two-parameter space. ► We characterize self-similar properties of Arnold tongues and shrimps for a two-gene model. ► We determine the period of the Arnold tongues recognizing a Fibonacci-type sequence. ► We explore self-similar features of the shrimps identifying multiple period-three structures.
Fan, M; Wang, K; Jiang, D
1999-08-01
In this paper, we study the existence and global attractivity of positive periodic solutions of periodic n-species Lotka-Volterra competition systems. By using the method of coincidence degree and Lyapunov functional, a set of easily verifiable sufficient conditions are derived for the existence of at least one strictly positive (componentwise) periodic solution of periodic n-species Lotka-Volterra competition systems with several deviating arguments and the existence of a unique globally asymptotically stable periodic solution with strictly positive components of periodic n-species Lotka-Volterra competition system with several delays. Some new results are obtained. As an application, we also examine some special cases of the system we considered, which have been studied extensively in the literature. Some known results are improved and generalized.
ALMOST PERIODIC SOLUTION OF A NONAUTONOMOUS DIFFUSIVE FOOD CHAIN SYSTEM OF THREE SPECIES
Institute of Scientific and Technical Information of China (English)
LuoGuilie
1999-01-01
In this paper,the almost periodic nonautonomous diffusive food chain system of threespecies is discussed. By using the comparison theorem and V-function method,the author provesthe existence and uniqueness of a positive almost periodic solution,and its stability under disturbances from the hull.
Theoretical Basis and Correct Explanation of the Periodic System: Review and Update
Schwarz, W. H. Eugen; Rich, Ronald L.
2010-01-01
Long-standing questions on the theoretical basis of the periodic system have been answered in recent years. A specific type of periodicity is imposed on all elements by the main groups just before and after the noble gasses. The upper "n"p shells of these elements are unique because of their stabilized energies and the large gaps to the next…
RESEARCH OF THE PERIODIC MOTION AND STABILITY OF TWO-DEGREE-OF-FREEDOM NONLINEAR OSCILLATING SYSTEMS
Institute of Scientific and Technical Information of China (English)
刘俊
2002-01-01
The periodic motion and stability for a class of two-degree-of freedom nonlinear oscillating systems are studied by using the method of Liapunov function.The sufficient conditions which guarantee the existence, uniqueness and asymptotic stability of the periodic solutions are obtained.
Positive Periodic Solutions of Cooperative Systems with Delays and Feedback Controls
Directory of Open Access Journals (Sweden)
Tursuneli Niyaz
2013-01-01
Full Text Available This paper studies a class of periodic n species cooperative Lotka-Volterra systems with continuous time delays and feedback controls. Based on the continuation theorem of the coincidence degree theory developed by Gaines and Mawhin, some new sufficient conditions on the existence of positive periodic solutions are established.
Single rub-impacting periodic motions of a rigid constrained rotor system
Institute of Scientific and Technical Information of China (English)
QunhongLI; QishaoLU
2000-01-01
This paper discusses the existence of single rub-impacting period-n motions for a kind of rotor systems with rigid constraints. The ranges of parameters for period-2 motions are also given. An example of this method is given.
PERIODIC SOLUTIONS TO A KIND OF NEUTRAL DIFFERENTIAL SYSTEM:VIA (h,k)-DICHOTOMY
Institute of Scientific and Technical Information of China (English)
无
2012-01-01
In this paper, based on the theory of (h, k)-Dichotomy of linear system and Kras-noselskii's fixed point theorem, we study the existence of periodic solutions to a neutral differential equation. Some new sufficient conditions are obtained to guarantee the existence and uniqueness of T-periodic solution to the equation.
ON THE EXISTENCE OF PERIODIC SOLUTIONS FOR NONLINEAR SYSTEM WITH MULTIPLE DELAYS
Institute of Scientific and Technical Information of China (English)
曹显兵
2003-01-01
The existence of T-periodic solutions of the nonlinear system with multiple delaysis studied. By using the topological degree method, sufficient conditions are obtained forthe existence of T-periodic solutions. As an application, the existence of positive periodicsolution for a logarithmic population model is established under some conditions.
Periodic orbits and non-integrability of Henon-Heiles systems
Energy Technology Data Exchange (ETDEWEB)
Llibre, Jaume [Departament de Matematiques, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona, Catalonia (Spain); Jimenez-Lara, Lidia, E-mail: jllibre@mat.uab.cat, E-mail: lidia@xanum.uam.mx [Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, PO Box 55-534, Mexico, DF, 09340 Mexico (Mexico)
2011-05-20
We apply the averaging theory of second order to study the periodic orbits for a generalized Henon-Heiles system with two parameters, which contains the classical Henon-Heiles system. Two main results are shown. The first result provides sufficient conditions on the two parameters of these generalized systems, which guarantee that at any positive energy level, the Hamiltonian system has periodic orbits. These periodic orbits form in the whole phase space a continuous family of periodic orbits parameterized by the energy. The second result shows that for the non-integrable Henon-Heiles systems in the sense of Liouville-Arnol'd, which have the periodic orbits analytically found with averaging theory, cannot exist any second first integral of class C{sup 1}. In particular, for any second first integral of class C{sup 1}, we prove that the classical Henon-Heiles system and many generalizations of it are not integrable in the sense of Liouville-Arnol'd. Moreover, the tools we use for studying the periodic orbits and the non-Liouville-Arnol'd integrability can be applied to Hamiltonian systems with an arbitrary number of degrees of freedom.
Reithmeier, Eduard
1991-01-01
Limit cycles or, more general, periodic solutions of nonlinear dynamical systems occur in many different fields of application. Although, there is extensive literature on periodic solutions, in particular on existence theorems, the connection to physical and technical applications needs to be improved. The bifurcation behavior of periodic solutions by means of parameter variations plays an important role in transition to chaos, so numerical algorithms are necessary to compute periodic solutions and investigate their stability on a numerical basis. From the technical point of view, dynamical systems with discontinuities are of special interest. The discontinuities may occur with respect to the variables describing the configuration space manifold or/and with respect to the variables of the vector-field of the dynamical system. The multiple shooting method is employed in computing limit cycles numerically, and is modified for systems with discontinuities. The theory is supported by numerous examples, mainly fro...
Positive Periodic Solution of Second-Order Coupled Systems with Singularities
Directory of Open Access Journals (Sweden)
Tiantian Ma
2013-01-01
Full Text Available This paper establishes the existence of periodic solution for a kind of second-order singular nonautonomous coupled systems. Our approach is based on fixed point theorem in cones. Examples are given to illustrate the main result.
Existence of infinitely many periodic solutions for second-order nonautonomous Hamiltonian systems
Directory of Open Access Journals (Sweden)
Wen Guan
2015-04-01
Full Text Available By using minimax methods and critical point theory, we obtain infinitely many periodic solutions for a second-order nonautonomous Hamiltonian systems, when the gradient of potential energy does not exceed linear growth.
EXISTENCE AND UNIQUENESS OF PERIODIC SOLUTIONS FOR GRADIENT SYSTEMS IN FINITE DIMENSIONAL SPACES
Institute of Scientific and Technical Information of China (English)
Sahbi BOUSSANDEL
2016-01-01
This paper deals with an abstract periodic gradient system in which the gradient is taken with respect to a variable metric. We obtain an existence and uniqueness result via the application of a global inverse theorem.
External Periodic Force Control of a Single-Degree-of-Freedom Vibroimpact System
Directory of Open Access Journals (Sweden)
Jingyue Wang
2013-01-01
Full Text Available A single-degree-of-freedom mechanical model of vibro-impact system is established. Bifurcation and chaos in the system are revealed with the time history diagram, phase trajectory map, and Poincaré map. According to the bifurcation and chaos of the actual vibro-impact system, the paper puts forward external periodic force control strategy. The method of controlling chaos by external periodic force feedback controller is developed to guide chaotic motions towards regular motions. The stability of the control system is also analyzed especially by theory. By selecting appropriate feedback coefficients, the unstable periodic orbits of the original chaotic orbit can be stabilized to the stable periodic orbits. The effectiveness of this control method is verified by numerical simulation.
Scaling of Moon Masses and Orbital Periods in the Systems of Saturn, Jupiter and Uranus
Müller H
2015-01-01
The paper shows, that the sequence of sorted by value masses of the largest moons in the systems of Saturn, Jupiter and Uranus is connected by constant scaling exponents with the sequence of their sorted by value orbital periods.
Mirus, Kevin Andrew
In this thesis, the possibility of controlling low- and high-dimensional chaotic systems by periodically driving an accessible system parameter is examined. This method has been carried out on several numerical systems and the MST Reversed Field Pinch. The numerical systems investigated include the logistic equation, the Lorenz equations, the Rossler equations, a coupled lattice of logistic equations, a coupled lattice of Lorenz equations, the Yoshida equations, which model tearing mode fluctuations in a plasma, and a neural net model for magnetic fluctuations on MST. This method was tested on the MST by sinusoidally driving a magnetic flux through the toroidal gap of the device. Numerically, periodic drives were found to be most effective at producing limit cycle behavior or significantly reducing the dimension of the system when the perturbation frequency was near natural frequencies of unstable periodic orbits embedded in the attractor of the unperturbed system. Several different unstable periodic orbits have been stabilized in this way for the low-dimensional numerical systems, sometimes with perturbation amplitudes that were less than 5% of the nominal value of the parameter being perturbed. In high- dimensional systems, limit cycle behavior and significant decreases in the system dimension were also achieved using perturbations with frequencies near the natural unstable periodic orbit frequencies. Results for the MST were not this encouraging, most likely because of an insufficient drive amplitude, the extremely high dimension of the plasma behavior, large amounts of noise, and a lack of stationarity in the transient plasma pulses.
Energy Technology Data Exchange (ETDEWEB)
Mirus, K.A.
1998-06-01
In this thesis, the possibility of controlling low- and high-dimensional chaotic systems by periodically driving an accessible system parameter is examined. This method has been carried out on several numerical systems and the MST Reversed Field Pinch. The numerical systems investigated include the logistic equation, the Lorenz equations, the Roessler equations, a coupled lattice of logistic equations, a coupled lattice of Lorenz equations, the Yoshida equations, which model tearing mode fluctuations in a plasma, and a neural net model for magnetic fluctuations on MST. This method was tested on the MST by sinusoidally driving a magnetic flux through the toroidal gap of the device. Numerically, periodic drives were found to be most effective at producing limit cycle behavior or significantly reducing the dimension of the system when the perturbation frequency was near natural frequencies of unstable periodic orbits embedded in the attractor of the unperturbed system. Several different unstable periodic orbits have been stabilized in this way for the low-dimensional numerical systems, sometimes with perturbation amplitudes that were less than 5% of the nominal value of the parameter being perturbed. In high-dimensional systems, limit cycle behavior and significant decreases in the system dimension were also achieved using perturbations with frequencies near the natural unstable periodic orbit frequencies. Results for the MST were not this encouraging, most likely because of an insufficient drive amplitude, the extremely high dimension of the plasma behavior, large amounts of noise, and a lack of stationarity in the transient plasma pulses.
International Nuclear Information System (INIS)
In this thesis, the possibility of controlling low- and high-dimensional chaotic systems by periodically driving an accessible system parameter is examined. This method has been carried out on several numerical systems and the MST Reversed Field Pinch. The numerical systems investigated include the logistic equation, the Lorenz equations, the Roessler equations, a coupled lattice of logistic equations, a coupled lattice of Lorenz equations, the Yoshida equations, which model tearing mode fluctuations in a plasma, and a neural net model for magnetic fluctuations on MST. This method was tested on the MST by sinusoidally driving a magnetic flux through the toroidal gap of the device. Numerically, periodic drives were found to be most effective at producing limit cycle behavior or significantly reducing the dimension of the system when the perturbation frequency was near natural frequencies of unstable periodic orbits embedded in the attractor of the unperturbed system. Several different unstable periodic orbits have been stabilized in this way for the low-dimensional numerical systems, sometimes with perturbation amplitudes that were less than 5% of the nominal value of the parameter being perturbed. In high-dimensional systems, limit cycle behavior and significant decreases in the system dimension were also achieved using perturbations with frequencies near the natural unstable periodic orbit frequencies. Results for the MST were not this encouraging, most likely because of an insufficient drive amplitude, the extremely high dimension of the plasma behavior, large amounts of noise, and a lack of stationarity in the transient plasma pulses
The periodic wave solutions for two systems of nonlinear wave equations
Institute of Scientific and Technical Information of China (English)
王明亮; 王跃明; 张金良
2003-01-01
The periodic wave solutions for the Zakharov system of nonlinear wave equations and a long-short-wave interaction system are obtained by using the F-expansion method, which can be regarded as an overall generalization of Jacobi elliptic function expansion proposed recently. In the limit cases, the solitary wave solutions for the systems are also obtained.
KONG, LIANG; Rawal, Nar; Shen, Wenxian
2014-01-01
The current paper is concerned with the existence of spreading speeds and linear determinacy for two species competition systems with nonlocal dispersal in time and space periodic habitats. The notion of spreading speed intervals for such a system is first introduced via the natural features of spreading speeds. The existence and lower bounds of spreading speed intervals are then established. When the periodic dependence of the habitat is only on the time variable, the existence of a single s...
Institute of Scientific and Technical Information of China (English)
Liu Su-Hua; Tang Jia-Shi; Qin Jin-Qi; Yin Xiao-Bo
2008-01-01
Bifurcation characteristics of the Langford system in a general form are systematically analysed,and nonlinear controls of periodic solutions changing into invariant tori in this system are achieved.Analytical relationship between control gain and bifurcation parameter is obtained.Bifurcation diagrams are drawn,showing the results of control for secondary Hopf bifurcation and sequences of bifurcations route to chaos.Numerical simulations of quasi-periodic tori validate analytic predictions.
Almost Periodic Solution of a Multispecies Discrete Mutualism System with Feedback Controls
Directory of Open Access Journals (Sweden)
Hui Zhang
2015-01-01
Full Text Available We consider an almost periodic multispecies discrete Lotka-Volterra mutualism system with feedback controls. We firstly obtain the permanence of the system by utilizing the theory of difference equation. By means of constructing a suitable Lyapunov function, sufficient conditions are obtained for the existence of a unique positive almost periodic solution which is uniformly asymptotically stable. An example together with numerical simulation indicates the feasibility of the main result.
Condition for emergence of the Floquet-Gibbs state in periodically driven open systems
Shirai, Tatsuhiko; Mori, Takashi; MIYASHITA, Seiji
2014-01-01
We study probability distribution of a steady state of a periodically driven system coupled to a thermal bath by using a quantum master equation in the weak coupling limit. It is proved that, even when the external field is strong, the probability distribution is independent of the detailed nature of the thermal bath under the following conditions: (i) the Hamiltonian of the relevant system is bounded and the period of the driving field is short, (ii) the Hamiltonians for the driving field at...
Institute of Scientific and Technical Information of China (English)
Li Yue; Yang Baojun; Lu Peng; Li Shizhe
2003-01-01
In this letter, with the synthesis of usual cross-correlation detecting method andchaotic detecting method, a new detecting system for the weak periodic pulse signal is constituted,in which the two methods can play respective preponderance. Theoretical analyses and simulationstudies have shown that the detecting system is very sensitive to the periodic pulse signal understrong noise background and has exceedingly powerful capability of suppressing complex noise.
Stabilization of Periodic Solutions in a Thedered Satellite System by Damping Injection
DEFF Research Database (Denmark)
Larsen, Martin Birkelund; Blanke, Mogens
2009-01-01
A spacecraft with electrodynamic tether orbiting the Earth will be subject to a periodic forcing term induced by the variation of the magnetic field along the orbit. The periodic forcing term leads to a family of unstable periodic solutions for a tether carrying a constant current. This paper...... presents a control design for stabilizing these periodic solutions. The design consists of a control law for stabilising the open-loo equibrilibrium and a bias term which forces the system trajectory away from the equilibrium. The tether needs to be positioned away from open-loop equilibrium for the tether...... to affect the orbit parameters. An approximation of the periodic solutions of the closed loop system is found as a series expansion in the parameter plane spanned by the controller gain and the bias term. The stability of the solutions is investigated using linear Floquet analysis of the variational...
The Period-Ratio and Mass-Ratio Correlation in Extra-Solar Multiple Planetary Systems
Jiang, Ing-Guey; Hung, Wen-Liang
2015-01-01
Employing the data from orbital periods and masses of extra-solar planets in 166 multiple planetary systems, the period-ratio and mass-ratio of adjacent planet pairs are studied. The correlation between the period-ratio and mass-ratio is confirmed and found to have a correlation coefficient of 0.5303 with a 99% confidence interval (0.3807, 0.6528). A comparison with the distribution of synthetic samples from a Monte Carlo simulation reveals the imprint of planet-planet interactions on the formation of adjacent planet pairs in multiple planetary systems.
A study of the entanglement in systems with periodic boundary conditions
Panagiotou, E.; Tzoumanekas, C.; Lambropoulou, S.; Millett, K. C.; Theodorou, D. N.
2010-01-01
We define the local periodic linking number, LK, between two oriented closed or open chains in a system with three-dimensional periodic boundary conditions. The properties of LK indicate that it is an appropriate measure of entanglement between a collection of chains in a periodic system. Using this measure of linking to assess the extent of entanglement in a polymer melt we study the effect of CReTA algorithm on the entanglement of polyethylene chains. Our numerical results show that the sta...
Periodic functions with variable period
Pryjmak, M. V
2010-01-01
The examples of rhythmical signals with variable period are considered. The definition of periodic function with the variable period is given as a model of such signals. The examples of such functions are given and their variable periods are written in the explicit form. The system of trigonometric functions with the variable period is considered and its orthogonality is proved. The generalized system of trigonometric functions with the variable period is also suggested; some conditions of it...
New Light Curves and Period Studies of V502 OPH W UMA System
Awadalla, Nabil S.
NEW LIGHT CURVES AND PERIOD STUDIES OF V502 OPH W UMa SYSTEM N.S.Awadalla National Research Institute of Astronomy and Geophysics( NRIAG ) Helwan Cairo EGYPT New BVR photoelectric observations of the W UMa eclipsing binary system V502 Oph have been presented and analyzed. The geometric and physical elements of the system have been obtained and compared to the previous results. The classification of the system concerning the sub-type of the W UMa binary has been studied as well as its evolution stage. Its period variation in a view of the light time effect has been examin
Performance analysis for queueing systems with close down periods and server under maintenance
Krishna Kumar, B.; Anbarasu, S.; Lakshmi, S. R. Anantha
2015-01-01
A single server queue subject to maintenance of the server and the close down period is considered. We obtain explicit expressions for the transient probabilities of the system size, the server under maintenance state and the close down period. The time-dependent performance measures of the system and the probability density function of the first-passage-time to reach the maintenance state are discussed. The corresponding steady state analysis and key performance measures of the system are also presented. Finally, the effect of various parameters on system performance measures is demonstrated by a numerical example.
Periodic solutions for a two-species nonautonomous competition system with diffusion and impulses
Energy Technology Data Exchange (ETDEWEB)
Dong Lingzhen [Department of Mathematics, Taiyuan University of Technology, Taiyuan 030024 (China)]. E-mail: linzhen_dong@yahoo.com.cn; Chen Lansun [Department of Applied Mathematics, Dalian University of Technology, Dalian 116023 (China); Shi Peilin [Department of Mathematics, Taiyuan University of Technology, Taiyuan 030024 (China)
2007-06-15
By re-estimating the upper bound of {integral}{sub 0}{sup {omega}}e{sup u{sub i}}{sup (t)}dt (i=1,2), we generalize a result about the existence of a positive periodic solution for a two-species nonautonomous patchy competition system with time delay. Based on that system, we consider the impulsive harvesting and stocking, and establish a two-species nonautonomous competition Lotka-Volterra system with diffusion and impulsive effects. With the continuation theorem of coincidence degree theory, we obtain the existence of a positive periodic solution for such a system. At last, two examples are given to demonstrate our results.
Stationary distribution and periodic solutions for stochastic Holling-Leslie predator-prey systems
Jiang, Daqing; Zuo, Wenjie; Hayat, Tasawar; Alsaedi, Ahmed
2016-10-01
The stochastic autonomous and periodic predator-prey systems with Holling and Leslie type functional response are investigated. For the autonomous system, we prove that there exists a unique stationary distribution, which is ergodic by constructing a suitable Lyapunov function under relatively small white noise. The result shows that, stationary distribution doesn't rely on the existence and the stability of the positive equilibrium in the undisturbed system. Furthermore, for the corresponding non-autonomous system, we show that there exists a positive periodic Markov process under relatively weaker condition. Finally, numerical simulations illustrate our theoretical results.
Periodic orbits and their stability in the Rössler prototype-4 system
Energy Technology Data Exchange (ETDEWEB)
García, Isaac A., E-mail: garcia@matematica.udl.cat [Departament de Matemàtica, Universitat de Lleida, Avda. Jaume II, 69, 25001 Lleida, Catalonia (Spain); Llibre, Jaume, E-mail: jllibre@mat.uab.cat [Departament de Matemàtiques, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Catalonia (Spain); Maza, Susanna, E-mail: smaza@matematica.udl.cat [Departament de Matemàtica, Universitat de Lleida, Avda. Jaume II, 69, 25001 Lleida, Catalonia (Spain)
2012-07-02
For the Rössler prototype-4 system x{sup .}=−y−z, y{sup .}=x, z{sup .}=αy(1−y)−βz we prove the existence of periodic orbits and study their stability or instability. The main tool for proving these results is the averaging theory. Recently the existence of some of these periodic orbits were detected numerically. -- Highlights: ► We deal with the Rössler prototype-4 system x{sup .}=−y−z, y{sup .}=x, z{sup .}=αy(1−y)−βz. ► It is one of the simplest autonomous differential equations exhibiting chaos. ► Recently some periodic orbits for this system has been detected numerically. ► We provide an analytical proof of these orbits and study their stability. ► Also we prove the existence of periodic orbits not detected numerically.
Directory of Open Access Journals (Sweden)
N. Raos
2015-03-01
Full Text Available The teaching of the periodic system in the historical context has an advantage because students in this way comprehend more easily the basic chemical concepts, such as relative atomic mass, proton number, chemical element, elementary substance, equivalent and molar mass. The story of the periodic system also shows the following: (1 Before a key scientific discovery there is a long period of data collection and systematization, (2 Theories in chemistry must be based on experimental results and methods, (3 The advancement of science is also determined by the development of concepts, and (4 Scientific theories usually do not contradict but support each other. Therefore, the historical periodic system (based on relative atomic mass is not obsolete, but complementary to the modern.
Periodic orbits and their stability in the Rössler prototype-4 system
International Nuclear Information System (INIS)
For the Rössler prototype-4 system x.=−y−z, y.=x, z.=αy(1−y)−βz we prove the existence of periodic orbits and study their stability or instability. The main tool for proving these results is the averaging theory. Recently the existence of some of these periodic orbits were detected numerically. -- Highlights: ► We deal with the Rössler prototype-4 system x.=−y−z, y.=x, z.=αy(1−y)−βz. ► It is one of the simplest autonomous differential equations exhibiting chaos. ► Recently some periodic orbits for this system has been detected numerically. ► We provide an analytical proof of these orbits and study their stability. ► Also we prove the existence of periodic orbits not detected numerically.
DEFF Research Database (Denmark)
Rudner, Mark Spencer; Lindner, Netanel; Berg, Erez;
2013-01-01
Recently, several authors have investigated topological phenomena in periodically driven systems of noninteracting particles. These phenomena are identified through analogies between the Floquet spectra of driven systems and the band structures of static Hamiltonians. Intriguingly, these works ha...... that arise in driven systems. Possibilities for realizing these phenomena in solid-state and cold-atomic systems are discussed....... revealed phenomena that cannot be characterized by analogy to the topological classification framework for static systems. In particular, in driven systems in two dimensions (2D), robust chiral edge states can appear even though the Chern numbers of all the bulk Floquet bands are zero. Here, we elucidate......Recently, several authors have investigated topological phenomena in periodically driven systems of noninteracting particles. These phenomena are identified through analogies between the Floquet spectra of driven systems and the band structures of static Hamiltonians. Intriguingly, these works have...
Bifurcation for Second-Order Hamiltonian Systems with Periodic Boundary Conditions
Francesca Faraci; Antonio Iannizzotto
2008-01-01
Through variational methods, we study nonautonomous systems of second-order ordinary differential equations with periodic boundary conditions. First, we deal with a nonlinear system, depending on a function $u$ , and prove that the set of bifurcation points for the solutions of the system is not ${\\sigma{}} $ -compact. Then, we deal with a linear system depending on a real parameter ${\\lambda{}}>0$ and on a function $u$ , and prove that there exists ${{\\lambda{}}}^{{_\\ast}} $ such that the se...
Existence of positive periodic solution of mutualism system with several delays
Energy Technology Data Exchange (ETDEWEB)
Wu Haihui [College of Mathematics and Computer Science, Fuzhou University, Fuzhou 350002 (China); Department of Computer Science and Technology, Sunshine College, Fuzhou University, Fuzhou 350002 (China); Xia Yonghui [College of Mathematics and Computer Science, Fuzhou University, Fuzhou 350002 (China)], E-mail: yhxia@fzu.edu.cn; Lin Muren [College of Mathematics and Computer Science, Fuzhou University, Fuzhou 350002 (China)
2008-04-15
In this paper, by using Mawhin coincidence degree, some sufficient conditions are obtained for the global existence of positive periodic solutions of a mutualism systems with bounded and unbounded delays. Our results generalize significantly improve those of Gopalsamy and He [Gopalsamy K, He XZ. Persistence, attractivity, and delay in facultative mutualism. J Math Anal Appl 1997;215:154-73], Yang et al. [Yang F, Jiang D, Ying A. Existence of positive solution of multidelays facultative mutualism system. J Eng Math 2002;3:64-8], Chen et al. [Chen FD, Shi JL, Chen XX. Periodicity in Lotka-Volterra facultative mutualism system with several delays. J Eng Math 2004;21(3)] and Xia and Lin [Xia YH, Lin M, Existence of positive periodic solution of mutualism system with infinite delays. Ann Diff Eqs 2005;21(3):448-53].
Bifurcations and Periodic Solutions for an Algae-Fish Semicontinuous System
Directory of Open Access Journals (Sweden)
Chuanjun Dai
2013-01-01
Full Text Available We propose an algae-fish semicontinuous system for the Zeya Reservoir to study the control of algae, including biological and chemical controls. The bifurcation and periodic solutions of the system were studied using a Poincaré map and a geometric method. The existence of order-1 periodic solution of the system is discussed. Based on previous analysis, we investigated the change in the location of the order-1 periodic solution with variable parameters and we described the transcritical bifurcation of the system. Finally, we provided a series of numerical results to illustrate the feasibility of the theoretical results. These results may help to facilitate a better understanding of algal control in the Zeya Reservoir.
Local electric dipole moments for periodic systems via density functional theory embedding
International Nuclear Information System (INIS)
We describe a novel approach for the calculation of local electric dipole moments for periodic systems. Since the position operator is ill-defined in periodic systems, maximally localized Wannier functions based on the Berry-phase approach are usually employed for the evaluation of local contributions to the total electric dipole moment of the system. We propose an alternative approach: within a subsystem-density functional theory based embedding scheme, subset electric dipole moments are derived without any additional localization procedure, both for hybrid and non-hybrid exchange–correlation functionals. This opens the way to a computationally efficient evaluation of local electric dipole moments in (molecular) periodic systems as well as their rigorous splitting into atomic electric dipole moments. As examples, Infrared spectra of liquid ethylene carbonate and dimethyl carbonate are presented, which are commonly employed as solvents in Lithium ion batteries
Local electric dipole moments for periodic systems via density functional theory embedding
Energy Technology Data Exchange (ETDEWEB)
Luber, Sandra, E-mail: sandra.luber@chem.uzh.ch [Institut für Chemie, Universität Zürich, Winterthurerstrasse 190, 8057 Zürich (Switzerland)
2014-12-21
We describe a novel approach for the calculation of local electric dipole moments for periodic systems. Since the position operator is ill-defined in periodic systems, maximally localized Wannier functions based on the Berry-phase approach are usually employed for the evaluation of local contributions to the total electric dipole moment of the system. We propose an alternative approach: within a subsystem-density functional theory based embedding scheme, subset electric dipole moments are derived without any additional localization procedure, both for hybrid and non-hybrid exchange–correlation functionals. This opens the way to a computationally efficient evaluation of local electric dipole moments in (molecular) periodic systems as well as their rigorous splitting into atomic electric dipole moments. As examples, Infrared spectra of liquid ethylene carbonate and dimethyl carbonate are presented, which are commonly employed as solvents in Lithium ion batteries.
Energy Technology Data Exchange (ETDEWEB)
Zhao Hongyong [Department of Mathematics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)]. E-mail: hongyongz@126.com; Ding Nan [Department of Mathematics, Xinjiang Normal University, Urumqi 830054 (China)
2006-07-15
In this paper, Lotka-Volterra competition-predator system with variable delays is considered. Some sufficient conditions ensuring the existence and global attractivity of periodic solution for this system are obtained by using coincidence degree theory and Lyapunov functional method. An example is also worked out to demonstrate the advantages of our results.
Two-stage Maintenance of a Production System with Exponentially Distributed On- and Off-periods
Dijkhuizen, van Gerhard; Harten, van Aart
1998-01-01
We consider an on–off production system which is subject to failure during on-periods. In case of a failure, the production system is maintained correctively. In addition, preventive maintenance is carried out to prevent failures. The costs of both preventive and corrective maintenance are modelled
Valentinuzzi, M.
1973-01-01
Phase lag, maximal slow phase velocity, and beat frequency were measured in periodic Coriolis star nystagmus. The results have been described by Steinhausen's model of the semicircular canal system. Estimates of the biophysical constants have been obtained. It is concluded that this model is a good functional approximation for describing, and also for interpreting, the behavior of the system.
PERIODIC SOLUTION TO A DELAYED PREDATOR-PREY SYSTEM WITH STAGE STRUCTURE AND DISPERSION
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
In this paper,a delayed two-species predator-prey system with stage structure and diffiusion is investigated. Based on the continuation theorem of coincidence degree theory,the suficient conditions for the existence of positive ω-periodic solution to the system are derived. The numerical simulation of an example verifies our main result.
E.A. Koopman; C.P. Lowe
2014-01-01
We consider the problem of detecting a percolating structure in an off-lattice model polymer system when periodic boundary conditions are used. Physically, with increasing polymer density, the point at which this first occurs is the gel point. A connected structure spans all space and the system bec
The cyclicity of period annulus of a quadratic reversible Lotka-Volterra system
Li, Chengzhi; Llibre, Jaume
2009-12-01
We prove that by perturbing the periodic annulus of the quadratic polynomial reversible Lotka-Volterra differential system \\dot x=y+\\case{3}{2}(x^2-y^2) , \\dot y=-x(1-y) , inside the class of all quadratic polynomial differential systems we can obtain at most two limit cycles.
Sign reversal of drag in bilayer systems with in-plane periodic potential modulation
DEFF Research Database (Denmark)
Alkauskas, A.; Flensberg, Karsten; Hu, Ben Yu-Kuang;
2002-01-01
We develop a theory for describing frictional drag in bilayer systems with in-plane periodic potential modulations, and use it to investigate the drag between bilayer systems in which one of the layers is modulated in one direction. At low temperatures, as the density of carriers in the modulated...
Near Periodic solution of the Elliptic RTBP for the Jupiter Sun system
Perdomo, Oscar M
2016-01-01
Let us consider the elliptic restricted three body problem (Elliptic RTBP) for the Jupiter Sun system with eccentricity $e=0.048$ and $\\mu=0.000953339$. Let us denote by $T$ the period of their orbits. In this paper we provide initial conditions for the position and velocity for a spacecraft such that after one period $T$ the spacecraft comes back to the same place, with the same velocity, within an error of 4 meters for the position and 0.2 meters per second for the velocity. Taking this solution as periodic, we present numerical evidence showing that this solution is stable. In order to compare this periodic solution with the motion of celestial bodies in our solar system, we end this paper by providing an ephemeris of the spacecraft motion from February 17, 2017 to December 28, 2028.
Periodic Solutions of the Vlasov-Poisson System with Boundary Conditions
Bostan, Mihai; Poupaud, Frédéric
1998-01-01
We study the Vlasov-Poisson system with time periodic boundary conditions. For small data we prove existence of weak periodic solutions in any space dimension. In the one dimensional case the result is stronger: we obtain existence of mild solution and uniqueness of this solution when the data are smooth. It is necessary to impose a non vanishing condition for the incoming velocities in order to control the life-time of particles in the domain.
Jung, Soyeun
2012-01-01
In the previous paper \\cite{J1}, we established pointwise bounds for the Green function of the linearized equation associated with spatially periodic traveling waves $\\bar u$ of a system of reaction diffusion equations, and also obtained pointwise nonlinear stability and behavior of $\\bar u$ under small perturbations. In this paper, using periodic resolvent kernels and the Bloch-decomposition, we establish pointwise bounds for the Green function of the linearized equation associated with peri...
Existence of periodic solutions in shifts $\\delta_{\\pm}$ for neutral nonlinear dynamic systems
Adivar, Murat; Koyuncuoglu, H. Can; Youssef N. Raffoul
2014-01-01
In this study, we focus on the existence of a periodic solution for the neutral nonlinear dynamic systems with delay% \\[ x^{\\Delta}(t)=A(t)x(t)+Q^{\\Delta}\\left(t,x\\left(\\delta_{-}(s,t)\\right) \\right) +G\\left(t,x(t),x\\left(\\delta_{-}(s,t)\\right) \\right) . \\] We utilize the new periodicity concept in terms of shifts operators, which allows us to extend the concept of periodicity to time scales where the additivity requirement $t\\pm T\\in\\mathbb{T}$ for all $t\\in\\mathbb{T}$ and for a fixed $T>0,$...
Globally and locally attractive solutions for quasi-periodically forced systems
Bartuccelli, Michele V.; Deane, Jonathan H. B.; Gentile, Guido
2007-04-01
We consider a class of differential equations, , with , describing one-dimensional dissipative systems subject to a periodic or quasi-periodic (Diophantine) forcing. We study existence and properties of trajectories with the same quasi-periodicity as the forcing. For g(x)=x2p+1, , we show that, when the dissipation coefficient is large enough, there is only one such trajectory and that it describes a global attractor. In the case of more general nonlinearities, including g(x)=x2 (describing the varactor equation), we find that there is at least one trajectory which describes a local attractor.
Kunder, Andrea; Stetson, Peter B; Bono, Giuseppe; Nemec, James M; de Propris, Roberto; Monelli, Matteo; Cassisi, Santi; Andreuzzi, Gloria; Dall'Ora, Massimo; Di Cecco, Alessandra; Zoccali, Manuela
2010-01-01
We present period change rates (dP/dt) for 42 RR Lyrae variables in the globular cluster IC$\\,$4499. Despite clear evidence of these period increases or decreases, the observed period change rates are an order of magnitude larger than predicted from theoretical models of this cluster. We find there is a preference for increasing periods, a phenomenon observed in most RR Lyrae stars in Milky Way globular clusters. The period-change rates as a function of position in the period-amplitude plane are used to examine possible evolutionary effects in OoI clusters, OoII clusters, field RR Lyrae stars and the mixed-population cluster $\\omega$~ Centauri. It is found that there is no correlation between the period change rate and the typical definition of Oosterhoff groups. If the RR Lyrae period changes correspond with evolutionary effects, this would be in contrast to the hypothesis that RR Lyrae variables in OoII systems are evolved HB stars that spent their ZAHB phase on the blue side of the instability strip. This ...
Analysis of a Periodic Impulsive Predator-Prey System with Disease in the Prey
Directory of Open Access Journals (Sweden)
Lianwen Wang
2013-01-01
Full Text Available We investigate a periodic predator-prey system subject to impulsive perturbations, in which a disease can be transmitted among the prey species only, in this paper. With the help of the theory of impulsive differential equations and Lyapunov functional method, sufficient conditions for the permanence, global attractivity, and partial extinction of system are established, respectively. It is shown that impulsive perturbations contribute to the above dynamics of the system. Numerical simulations are presented to substantiate the analytical results.
Directory of Open Access Journals (Sweden)
Y. Saiki
2007-09-01
Full Text Available An infinite number of unstable periodic orbits (UPOs are embedded in a chaotic system which models some complex phenomenon. Several algorithms which extract UPOs numerically from continuous-time chaotic systems have been proposed. In this article the damped Newton-Raphson-Mees algorithm is reviewed, and some important techniques and remarks concerning the practical numerical computations are exemplified by employing the Lorenz system.
Recovery of systems with a linear filter and nonlinear delay feedback in periodic regimes.
Ponomarenko, V I; Prokhorov, M D
2008-12-01
We propose a set of methods for the estimation of the parameters of time-delay systems with a linear filter and nonlinear delay feedback performing periodic oscillations. The methods are based on an analysis of the system response to regular external perturbations and are valid only for systems whose dynamics can be perturbed. The efficiency of the methods is illustrated using both numerical and experimental data.
Periodic response of nonlinear dynamical system with large number of degrees of freedom
Indian Academy of Sciences (India)
B P Patel; S M Ibrahim; Y Nath
2009-12-01
In this paper, a methodology based on shooting technique and Newmark's time integration scheme is proposed for predicting the periodic responses of nonlinear systems directly from solution of second order equations of motion without transforming to double ﬁrst order equations. The proposed methodology is quite suitable for systems with large number of degrees of freedom such as the banded system of equations from ﬁnite element discretization.
Period selection for integrated controller tasks in cyber-physical systems
Directory of Open Access Journals (Sweden)
Du Chenglie
2015-06-01
Full Text Available Performance optimization of cyber-physical systems (CPS calls for co-design strategies that handle the issues in both computing domain and physical domain. Periods of controller tasks integrated into a uniprocessor system are related to both control performance and real-time schedulability analysis simultaneously. System performance improvement can be achieved by optimizing the periods of controller tasks. This paper extends an existing model to select task periods in real-time for CPS with fixed priority controller tasks scheduled by rate-monotonic algorithm. When all the tasks can be integrated, the analytic solution of the problem is derived by using the method of Lagrange multipliers and gradient descent method is evaluated to be suitable online. To further deal with the condition that the system is overloaded, an integrated method is proposed to select periods of tasks online by selecting a subset of tasks first and then optimizing the periods for them. Experimental results demonstrate that our method yields near-optimal result with a short running time.
Many-body position operator in lattice fermionic systems with periodic boundary conditions
Energy Technology Data Exchange (ETDEWEB)
Hetenyi, Balazs [Institut fuer Theoretische Physik, Technische Universitaet Graz, Petersgasse 16, A-8010 Graz (Austria); Mathematisches Institut, Fakultaet fuer Mathematik, Informatik und Statistik, Ludwig Maximilians Universitaet, Theresienstrasse 39, Muenchen 80333 (Germany)], E-mail: hetenyi@itp.tugraz.at
2009-10-16
A total position operator X in the position representation is derived for lattice fermionic systems with periodic boundary conditions. The operator is shown to be Hermitian, the generator of translations in momentum space, and its time derivative is shown to correspond to the total current operator in a periodic system. The operator is such that its moments can be calculated up to any order. To demonstrate its utility finite size scaling is applied to the Brinkman-Rice transition as well as to metallic and insulating Gutzwiller wavefunctions. (fast track communication)
Bifurcation for Second-Order Hamiltonian Systems with Periodic Boundary Conditions
Directory of Open Access Journals (Sweden)
Francesca Faraci
2008-02-01
Full Text Available Through variational methods, we study nonautonomous systems of second-order ordinary differential equations with periodic boundary conditions. First, we deal with a nonlinear system, depending on a function u, and prove that the set of bifurcation points for the solutions of the system is not ÃÂƒ-compact. Then, we deal with a linear system depending on a real parameter ÃŽÂ»>0 and on a function u, and prove that there exists ÃŽÂ»Ã¢ÂˆÂ— such that the set of the functions u, such that the system admits nontrivial solutions, contains an accumulation point.
A Moebius-Strip Representation of the Matrix-Product Periodic System of Diatomic Molecules
Hefferlin, Ray
2007-04-01
Periodic systems of diatomic and triatomic molecules are well tested and documented [1]. The 3D form of the diatomic system consists of blocks, each having all molecules with two fixed-row atoms, on which the molecules are addressed by their atomic group numbers. The blocks can be replaced by tori [2], but in either case many redundancies exist (e.g., CO and OC). The tori [3] may be replaced by Moebius strips [4] which remove the redundancies. This representation of the periodic system will be presented. [1] Hefferlin, R., ``The Periodic Systems of Molecules, Presuppositions, Problems, and Prospects,'' Baird, D., Scerri, E., and McIntyre, L., Editors, Philosophy of Chemistry, Boston Studies in the Philosophy of Science, Springer, Dodrecht, the Netherlands, 2006. [2] Hefferlin, R,. ``Matrix-Product Periodic Systems of Molecules,'' J. Chem. Inf. Comput. Sci, 34, 314-317 (1994). [3] Hall, D. E, ``Quantitative Evaluation of Musical Scale Tunings,'' AJP, 42, 543-552 (1974). [4] Blau, S. K., ``Good Music unfolds in Small Steps,'' Physics Today, October 2006, pp. 19-21.
Performance analysis of the periodic sequence DSSS system against CW interference
Institute of Scientific and Technical Information of China (English)
Anquan WEI; Lianfeng SHEN
2008-01-01
Based on the brief account of the performance analysis result of the direct sequence spread spectrum (DSSS) system against a single tone continuous wave (CW) interference obtained from the traditional standard Gaussian approximation (SGA) hypothesis, the mathe-matical expression of the interference component of the symbol decision variable in the periodic sequence DSSS system under CW interference was deduced and the actual performance of the periodic sequence DSSS system against CW interference was researched through theoretical analysis and numerical simulations. The results indicate that the interference component of the symbol decision variable in the periodic sequence DSSS system under CW interference operates at a constant level or fluctuate monochromatically, which does not approach the standard Gaussian distribution, and the actual performance of the periodic sequence DSSS system against CW interference is completely different from the analytic result resorted to the standard Gaussian approximation (SGA). The bit error perfor-mance is correlative not only with the interference-signal ratio (ISR), the frequency offset and the phase of the CW interference sensitively, but also with the individual spread spectrum code sequence.
Ultra Short Period Planets in K2 with companions: a double transiting system for EPIC 220674823
Adams, Elisabeth R; Endl, Michael; Cochran, William D; MacQueen, Phillip J; Duev, Dmitry A; Jensen-Clem, Rebecca; Salama, Maïssa; Ziegler, Carl; Baranec, Christoph; Kulkarni, Shrinivas; Law, Nicholas M; Riddle, Reed
2016-01-01
Two transiting planets have been identified orbiting K2 target EPIC 220674823. One object is an ultra-short-period planet with a period of just 0.57 days (13.7 hours), while the other has a period of 13.3 days. Both planets are small, with the former having a radius of R_p1=1.5 R_E and the latter R_p2=2.5 R_E. Follow-up observations, including radial velocity (with uncertainties of 110 m/s) and high-resolution adaptive optics imagery, show no signs of stellar companions. EPIC 220674823 is the twelfth confirmed or validated planetary system in which an ultra-short-period planet (i.e., having an orbital period less than one day) is accompanied by at least one additional planet, suggesting that such systems may be common and must be accounted for in models for the formation and evolution of such extreme systems.
Directory of Open Access Journals (Sweden)
Henryk Flashner
1997-01-01
Full Text Available A point mapping analysis is employed to investigate the stability of periodic systems. The method is applied to simplified rotorcraft models. The proposed approach is based on a procedure to obtain an analytical expression for the period-to-period mapping description of system's dynamics, and its dependence on system's parameters. Analytical stability and bifurcation conditions are then determined and expressed as functional relations between important system parameters. The method is applied to investigate the parametric stability of flapping motion of a rotor and the ground resonance problem encountered in rotorcraft dynamics. It is shown that the proposed approach provides very accurate results when compared with direct numerical results which are assumed to be an “exact solution” for the purpose of this study. It is also demonstrated that the point mapping method yields more accurate results than the widely used classical perturbation analysis. The ability to perform analytical stability studies of systems with multiple degrees-of-freedom is an important feature of the proposed approach since most existing analysis methods are applicable to single degree-of-freedom systems. Stability analysis of higher dimensional systems, such as the ground resonance problems, by perturbation methods is not straightforward, and is usually very cumbersome.
Nonlinearity and periodic solution of a standard-beam balance oscillation system
Institute of Scientific and Technical Information of China (English)
Li Shi-Song; Lan Jiang; Han Bing; Tan Hong; Li Zheng-Kun
2012-01-01
We present the motion equation of the standard-beam balance oscillation system,whose beam and suspensions,compared with the compound pendulum,are connected flexibly and vertically.The nonlinearity and the periodic solution of the equation are discussed by the phase-plane analysis.We find that this kind of oscillation can be equivalent to a standard-beam compound pendulum without suspensions; however,the equivalent mass centre of the standard beam is extended.The derived periodic solution shows that the oscillation period is tightly related to the initial pivot energy and several systemic parameters:beam length,masses of the beam,and suspensions,and the beam mass centre.A numerical example is calculated.
Control of stochastic resonance in bistable systems by using periodic signals
Institute of Scientific and Technical Information of China (English)
Lin Min; Fang Li-Min; Zheng Yong-Jun
2009-01-01
According to the characteristic structure of double wells in bistable systems, this paper analyses stochastic fluctu-ations in the single potential well and probability transitions between the two potential wells and proposes a method of controlling stochastic resonance by using a periodic signal. Results of theoretical analysis and numerical simulation show that the phenomenon of stochastic resonance happens when the time scales of the periodic signal and the noise-induced probability transitions between the two potential wells achieve stochastic synchronization. By adding a bistable system with a controllable periodic signal, fluctuations in the single potential well can be effectively controlled, thus affecting the probability transitions between the two potential wells. In this way, an effective control can be achieved which allows one to either enhance or realize stochastic resonance.
Modal Vibration Control in Periodic Time-Varying Structures with Focus on Rotor Blade Systems
DEFF Research Database (Denmark)
Christensen, Rene Hardam; Santos, Ilmar
2004-01-01
The demands for high efficiency machines initiate a demand for monitoring and active control of vibrations to improve machinery performance and to prolong machinery lifetime. Applying active control to reduce vibrations in flexible bladed rotor-systems imply that several difficulties have...... of active modal controllers. The main aim is to reduce vibrations in periodic time-varying structures. Special emphasis is given to vibration control of coupled bladed rotor systems. A state feedback modal control law is developed based on modal analysis in periodic time-varying structures. The first step...... in the procedure is a transformation of the model into a time-invariant modal form by applying the modal matrices, which are also periodic time-variant. Due to coupled rotor and blade motions complex vibration modes occur in the modal transformed state space model. This implies that the modal transformed model...
Modal Vibration Control in Periodic Time-Varying Structures with Focus on Rotor-Blade Systems
DEFF Research Database (Denmark)
Christensen, Rene Hardam; Santos, Ilmar
2003-01-01
The demands for high efficiency machines initiate a demand for monitoring and active control of vibrations to improve machinery performance and to prolong machinery lifetime. Applying active control to reduce vibrations in flexible bladed rotor-systems imply that several difficulties have...... of active modal controllers. The main aim is to reduce vibrations in periodic time-varying structures. Special emphasis is given to vibration control of coupled bladed rotor systems. A state feedback modal control law is developed based on modal analysis in periodic time-varying structures. The first step...... in the procedure is a transformation of the model into a time-invariant modal form by applying the modal matrices, which are also periodic time-variant. Due to coupled rotor and blade motions complex vibration modes occur in the modal transformed state space model. This implies that the modal transformed model...
Zuo, Wenjie; Jiang, Daqing
2016-07-01
In this paper, we investigate the dynamics of the stochastic autonomous and non-autonomous predator-prey systems with nonlinear predator harvesting respectively. For the autonomous system, we first give the existence of the global positive solution. Then, in the case of persistence, we prove that there exists a unique stationary distribution and it has ergodicity by constructing a suitable Lyapunov function. The result shows that, the relatively weaker white noise will strengthen the stability of the system, but the stronger white noise will result in the extinction of one or two species. Particularly, for the non-autonomous periodic system, we show that there exists at least one nontrivial positive periodic solution according to the theory of Khasminskii. Finally, numerical simulations illustrate our theoretical results.
Periodic solutions of a multi-DOF beam system with impact
Vorst, E.L.B. van de; Campen, D.H. van; Kraker, A. de; Fey, R.H.B
1996-01-01
The steady state behaviour is analyzed of a periodically driven multi-DOF beam system which has an elastic stop at its middle. The elastic stop is modelled in a continuous way by using the contact law of Hertz. The beam is modelled by using finite elements and subsequently reduced by using a compone
Quasi-periodic Bifurcations of Invariant Circles in Low-dimensional Dissipative Dynamical Systems
Vitolo, Renato; Broer, Henk; Simo, Carles
2011-01-01
This paper first summarizes the theory of quasi-periodic bifurcations for dissipative dynamical systems. Then it presents algorithms for the computation and continuation of invariant circles and of their bifurcations. Finally several applications are given for quasiperiodic bifurcations of Hopf, sad
Periodic Solution for Diffusive Predator-Prey System with Functional Response
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
In this paper, a three species diffusive predator-prey model with functional response is studied, where all parameters are time dependent. By using the continuation theorem of coincidence degree theory, the existence of a positive periodic solution for this system is established.
Sturm intersection theory for periodic Jacobi matrices and linear Hamiltonian systems
Schulz-Baldes, Hermann
2011-01-01
Sturm-Liouville oscillation theory for periodic Jacobi operators with matrix entries is discussed and illustrated. The proof simplifies and clarifies the use of intersection theory of Bott, Maslov and Conley-Zehnder. It is shown that the eigenvalue problem for linear Hamiltonian systems can be dealt with by the same approach.
H-infinity Control of Linear Systems with Almost Periodic Inputs
DEFF Research Database (Denmark)
Larsen, Mikael
1996-01-01
In this paper we consider the class of linear, infinitedimensional systems with bounded input and output operators. Wederive and QTR H-infinity type result, formulated for thecase where the input signals are almost periodic in a generalizedsense. Control probelms, for which this result is relevant...
Dynamical stability of quasi-periodic response solutions in planar conservative systems
Hanssmann, H.; Simo, Carles
2011-01-01
We study non-autonomous planar Hamiltonian or reversible vector fields that vanish at the origin. The time-dependence is quasi-periodic with strongly non-resonant frequencies. First we give a simple criterion in terms of the averaged system for the trivial solution to be dynamically stable. Then we
Uniqueness of Traveling Waves for a Two-Dimensional Bistable Periodic Lattice Dynamical System
Chin-Chin Wu
2012-01-01
We study traveling waves for a two-dimensional lattice dynamical system with bistable nonlinearity in periodic media. The existence and the monotonicity in time of traveling waves can be derived in the same way as the one-dimensional lattice case. In this paper, we derive the uniqueness of nonzero speed traveling waves by using the comparison principle and the sliding method.
Directory of Open Access Journals (Sweden)
Bian-Xia Yang
2013-05-01
Full Text Available In this article, we consider the existence and multiplicity of positive periodic solutions for a first-order singular system with impulse effects. The proof of our main result is based on Krasnoselskii's fixed point theorem in a cone.
Formation of nonlinear holographic images in a system of periodically located nonlinear mediums
Directory of Open Access Journals (Sweden)
Belkov S.A.
2013-11-01
Full Text Available The formation of nonlinear holographic images in a system of periodically located nonlinear mediums is studied. Analytical expressions which describe the magnitudes and locations of intensity maximums depending on the corresponding image number are derived. Comparison with numerical calculation results is presented.
Global stabilization of linear periodically time-varying switched systems via matrix inequalities
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
In this paper, we address the stabilization problem for linear periodically time-varying switched systems.Using discretization technique, we derive new conditions for the global stabilizability in terms of the solution of matrix inequalities. An algorithm for finding stabilizing controller and switching strategy is presented.
Directory of Open Access Journals (Sweden)
Xinggui Liu
2011-01-01
Full Text Available In this paper, by using Mawhin's continuation theorem of coincidence degree theory, we establish the existence of at least four positive periodic solutions for a discrete time Lotka-Volterra competitive system with harvesting terms. An example is given to illustrate the effectiveness of our results.
A New Method for Studying the Periodic System Based on a Kohonen Neural Network
Chen, David Zhekai
2010-01-01
A new method for studying the periodic system is described based on the combination of a Kohonen neural network and a set of chemical and physical properties. The classification results are directly shown in a two-dimensional map and easy to interpret. This is one of the major advantages of this approach over other methods reported in the…
Scaling of Moon Masses and Orbital Periods in the Systems of Saturn, Jupiter and Uranus
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Müller H.
2015-04-01
Full Text Available The paper shows, that the sequence of sorted by value masses of the largest moons in the systems of Saturn, Jupiter and Uranus is connected by constant scaling exponents with the sequence of their sorted by value orbital periods.
Surface N Balances in Agricultural Crop production systems in China for the period 1980-2015
Sun, B.; Shen, R.P.; Bouwman, A.F.
2008-01-01
Surface nitrogen (N) balances for China's crop production systems were estimated using statistical data collected from 1980 to 2004 at the national and provincial scale and from 1994 to 1999 at the county level. There was a surplus N balance throughout these periods, but the surplus was nearly stabl
ON SOLVING PERIODIC BOUNDARY PROBLEM OF SEMILINEAR SYSTEMS WITH A ONE-PARAMETER IMBEDDING
Institute of Scientific and Technical Information of China (English)
刘国庆; 傅冬生; 沈祖和
2003-01-01
The paper is concerned with solving periodic boundary problem of semilinear systems,which will be differentiably embedded into an one-parameter family of operators.The solution of the systems is then found by continuing the solution curve of operator homotopy.When the Newton-Kantorovich's procedure is applied to the corresponding operator equations,an efficient algorithm is derived.Finally,the theoretical results are in excellent agreement with the numerical examples.
Cooperative Behavior in Driven Lattice Systems with Shifted Periodic Boundary Conditions
Anderson, Mark Jule Jr.
1998-01-01
We explore the nature of driven stochastic lattice systems with non-periodic boundary conditions. The systems consist of particle and holes which move by exchanges of nearest neighbor particle-hole pairs. These exchanges are controlled by the energetics associated with an internal Hamiltonian, an external drive and a stochastic coupling to a heat reservoir. The effect of the drive is to bias particle-hole exchanges along the field in such a way that a particle current ...
Foschi , Silvia; Mingari Scarpello, Giovanni; Ritelli, Daniele
2004-01-01
In 1985 Franz Rothe [16] found, by means of the thermodynamical equilibrium theory, an asymptotic estimate of period of solutions of Ordinary Differential Equations originated by predator - prey Volterra – Lotka model. We extend some of Rothe’s ideas to more general systems and succeed in calculating the period’s asymptotic analytic expression as a function of the energy level. We ﬁnally check our result reobtaining classical period’s estimation of some popular Hamiltonian systems. We apply o...
Employment System for the College Graduates in China during Planned Economy Period
Chen, Rui Juan
2004-01-01
The purpose of this paper is to examine basic structure of the employment system for the college graduates in China during planned economy period. Under planned economy system, college graduates were recruited centrally by the governments, and tuitions, fees and stipend were given by the government, and job placement of the graduates are done by the governments in cooperation with colleges and universities. National department of education, national department of planning, national and local ...
NUMERICAL SOLUTION OF THE GODUNOV - SULTANGAZIN SYSTEM OF EQUATIONS. PERIODIC CASE
Vasil’eva Ol’ga Aleksandrovna
2016-01-01
The Cauchy problem of the Godunov - Sultangazin system of equations with periodic initial conditions is considered in the article. The Godunov - Sultangazin system of equations is a model problem of the kinetic theory of gases. It is a discrete kinetic model of one-dimensional gas consisting of identical monatomic molecules. The molecules can have one of three speeds. So, there are three groups of molecules. The molecules of the first two groups have the speeds equal in values and opposite in...
NUMERICAL SOLUTION OF THE GODUNOV - SULTANGAZIN SYSTEM OF EQUATIONS. PERIODIC CASE
Directory of Open Access Journals (Sweden)
Vasil’eva Ol’ga Aleksandrovna
2016-04-01
Full Text Available The Cauchy problem of the Godunov - Sultangazin system of equations with periodic initial conditions is considered in the article. The Godunov - Sultangazin system of equations is a model problem of the kinetic theory of gases. It is a discrete kinetic model of one-dimensional gas consisting of identical monatomic molecules. The molecules can have one of three speeds. So, there are three groups of molecules. The molecules of the first two groups have the speeds equal in values and opposite in directions. The molecules of the third group have zero speed. The considered mathematical model has a number of properties of Boltzmann equation. This system of the equations is a quasi-linear system of partial differential equations. There is no analytic solution for this problem in the general case. So, numerical investigation of the Cauchy problem of the Godunov - Sultangazin system is very important. The finite-difference method of the first order is used for numerical investigation of the Cauchy problem of the Godunov - Sultangazin system of equations. The paper presents and discusses the results of numerical investigation of the Cauchy problem for the studied system solution with periodic initial condition. The dependence of the time of stabilization of the Cauchy problem solution of Godunov - Sultangazin system of equations from the decreasing parameter of system are obtained. The paper presents the dependence of time of energy exchange from the decreasing parameter. The solution stabilization to the equilibrium state is obtained. The stabilization time of Godunov - Sultangazin system solution is compared to the stabilization time of Carleman system solution in periodic case. The results of numerical investigation are in good agreement with the theoretical results obtained previously.
PERIODIC BOUNDARY VALUE PROBLEM OF QUASILINEAR SYSTEM%拟线性系统周期边值问题
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The existence and uniqueness results about quasilinear periodic boundary value problems are established by using the global inverse function theorem and the result about the existence and uniquencess of periodic solutions for the periodic boundary value problem of nonhomogeneous linear periodic system.
A population of planetary systems characterized by short-period, Earth-sized planets
Steffen, Jason H
2016-01-01
We analyze data from the Quarter 1-17 Data Release 24 (Q1--Q17 DR24) planet candidate catalog from NASA's Kepler mission, specifically comparing systems with single transiting planets to systems with multiple transiting planets, and identify a distinct population of exoplanets with a necessarily distinct system architecture. Such an architecture likely indicates a different branch in their evolutionary past relative to the typical Kepler system. The key feature of these planetary systems is an isolated, Earth-sized planet with a roughly one-day orbital period. We estimate that at least 24 of the 144 systems we examined (>~17%) are members of this population. Accounting for detection efficiency, such planetary systems occur with a frequency similar to the hot Jupiters.
Some Periodic Solutions of the Two-Dimensional Stokes-Oldroyd-B System with Stress Diffusion
Isaacson, Erica Amy
2012-01-01
We use a limited memory BFGS optimization method to seek time-periodic solutions of the Stokes-Oldroyd-B system of equations with a 4-roller forcing field and periodic boundary conditions. The gradient of the objective function for the optimization is found using a method which is based on the calculus of variations, and employs a pseudo-spectral implicit-explicit Runge-Kutta scheme. Once solutions are found, their asymptotic stability is calculated via an eigenvalue method. A variety of s...
Logic Model Checking of Time-Periodic Real-Time Systems
Florian, Mihai; Gamble, Ed; Holzmann, Gerard
2012-01-01
In this paper we report on the work we performed to extend the logic model checker SPIN with built-in support for the verification of periodic, real-time embedded software systems, as commonly used in aircraft, automobiles, and spacecraft. We first extended the SPIN verification algorithms to model priority based scheduling policies. Next, we added a library to support the modeling of periodic tasks. This library was used in a recent application of the SPIN model checker to verify the engine control software of an automobile, to study the feasibility of software triggers for unintended acceleration events.
Neighborhoods of periodic orbits and the stationary distribution of a noisy chaotic system.
Heninger, Jeffrey M; Lippolis, Domenico; Cvitanović, Predrag
2015-12-01
The finest state-space resolution that can be achieved in a physical dynamical system is limited by the presence of noise. In the weak-noise approximation, the stochastic neighborhoods of deterministic periodic orbits can be computed from distributions stationary under the action of a local Fokker-Planck operator and its adjoint. We derive explicit formulas for widths of these distributions in the case of chaotic dynamics, when the periodic orbits are hyperbolic. The resulting neighborhoods form a basis for functions on the attractor. The global stationary distribution, needed for calculation of long-time expectation values of observables, can be expressed in this basis. PMID:26764789
Directory of Open Access Journals (Sweden)
Elisa M. Nabel
2013-11-01
Full Text Available Early temporary windows of heightened brain plasticity called critical periods developmentally sculpt neural circuits and contribute to adult behavior. Regulatory mechanisms of visual cortex development –the preeminent model of experience-dependent critical period plasticity- actively limit adult plasticity and have proved fruitful therapeutic targets to reopen plasticity and rewire faulty visual system connections later in life. Interestingly, these molecular mechanisms have been implicated in the regulation of plasticity in other functions beyond vision. Applying mechanistic understandings of critical period plasticity in the visual cortex to fear circuitry may provide a conceptual framework for developing novel therapeutic tools to mitigate aberrant fear responses in post traumatic stress disorder. In this review, we turn to the model of experience-dependent visual plasticity to provide novel insights for the mechanisms regulating plasticity in the fear system. Fear circuitry, particularly fear memory erasure, also undergoes age-related changes in experience-dependent plasticity. We consider the contributions of molecular brakes that halt visual critical period plasticity to circuitry underlying fear memory erasure. A major molecular brake in the visual cortex, perineuronal net formation, recently has been identified in the development of fear systems that are resilient to fear memory erasure. The roles of other molecular brakes, myelin-related Nogo receptor signaling and Lynx family proteins– endogenous inhibitors for nicotinic acetylcholine receptor, are explored in the context of fear memory plasticity. Such fear plasticity regulators, including epigenetic effects, provide promising targets for therapeutic interventions.
Chaotic dynamics of one-dimensional systems with periodic boundary conditions
Kumar, Pankaj; Miller, Bruce N.
2014-12-01
We provide appropriate tools for the analysis of dynamics and chaos for one-dimensional systems with periodic boundary conditions. Our approach allows for the investigation of the dependence of the largest Lyapunov exponent on various initial conditions of the system. The method employs an effective approach for defining the phase-space distance appropriate for systems with periodic boundaries and allows for an unambiguous test-orbit rescaling in the phase space required to calculate the Lyapunov exponents. We elucidate our technique by applying it to investigate the chaotic dynamics of a one-dimensional plasma with periodic boundaries. Exact analytic expressions are derived for the electric field and potential using Ewald sums, thereby making it possible to follow the time evolution of the plasma in simulations without any special treatment of the boundary. By employing a set of event-driven algorithms, we calculate the largest Lyapunov exponent, the radial distribution function, and the pressure by following the evolution of the system in phase space without resorting to numerical manipulation of the equations of motion. Simulation results are presented and analyzed for the one-dimensional plasma with a view to examining the dynamical and chaotic behavior exhibited by small and large versions of the system.
Spectral validation of the Whitham equations for periodic waves of lattice dynamical systems
Kabil, Buğra; Rodrigues, L. Miguel
2016-02-01
In the present contribution we investigate some features of dynamical lattice systems near periodic traveling waves. First, following the formal averaging method of Whitham, we derive modulation systems expected to drive at main order the time evolution of slowly modulated wavetrains. Then, for waves whose period is commensurable to the lattice, we prove that the formally-derived first-order averaged system must be at least weakly hyperbolic if the background waves are to be spectrally stable, and, when weak hyperbolicity is met, the characteristic velocities of the modulation system provide group velocities of the original system. Historically, for dynamical evolutions obeying partial differential equations, this has been proved, according to increasing level of algebraic complexity, first for systems of reaction-diffusion type, then for generic systems of balance laws, at last for Hamiltonian systems. Here, for their semi-discrete counterparts, we give at once simultaneous proofs for all these cases. Our main analytical tool is the discrete Bloch transform, a discrete analogue to the continuous Bloch transform. Nevertheless, we needed to overcome the absence of genuine space-translation invariance, a key ingredient of continuous analyses.
Busy Period Analysis of a Man-machine System Operating Subject To Different Physical Conditions
Directory of Open Access Journals (Sweden)
G S. Mokaddis
2005-01-01
Full Text Available This study deals with some characteristics of a single-unit of a man-machine system operating under different physical conditions. The failure, repair and change of physical conditions (good-poor are stochastically independent random variables each having an arbitrary distribution. The system analysed by some Markov process technique. The busy period, expected number of visits by the repairman and the cost per unit time in a steady state of the system are obtained. Several important results have been derived as particular cases.
Characteristics of Period-Doubling Bifurcation Cascades in Quasi-discontinuous Systems
Institute of Scientific and Technical Information of China (English)
WU Shun-Guang; HE Da-Ren
2001-01-01
Many systems can display a very short, rapid change stage (quasi-discontinuous region) inside a relatively very long and slow change process. A quantitative definition for the "quasi-discontinuity" in these systems has been introduced. With the aid of a simplified model, some extraordinary Feigenbaum constants have been found inside the period-doubling cascades, the relationship between the values of the extraordinary Feigenbaum constants and the quasi-discontinuity of the system has also been reported. The phenomenon has been observed in Pikovsky circuit and Rose-Hindmash model.
Renin-angiotensin system in thyroidectomized rats at different periods of development.
Jiménez, E; Ruiz, M; Montiel, M; Narvaez, J A; Dieguez, J L; Morell, M
1991-12-01
The relationship between the renal function and some components of the renin-angiotensin system has been studied in hypothyroid rats thyroidectomized surgically at different periods of their life. Changes in plasma renin concentration (PRC) depending on the period hypothyroidism were induced. Results showed that the renin release control could result from an equilibrium between the reduced beta-adrenergic activity and the marked natriuresis observed in hypothyroidism. A reduction in plasma angiotensinogen concentration (PAC), due to a decrease in its hepatic production, was observed in thyroidectomized animals. PAC reduction was independent of the hypothyroidism induction period. Alterations in plasma renin activity (PRA) were a consequence of PRC and PAC changes in thyroidectomized animals, as an increase in fractional sodium excretion (FENa) time course dependent, was found in these rats. PMID:1725739
Using sign patterns to detect the possibility of periodicity in biological systems.
Culos, G J; Olesky, D D; van den Driessche, P
2016-04-01
Many models in the physical and life sciences, formulated as dynamical systems, exhibit a positive steady state, with its local qualitative behavior determined by the eigenvalues of its Jacobian matrix. Our interest lies in detecting if this steady state is linearly stable or if the system has periodic solutions arising from a Hopf bifurcation. We address this by considering the sign pattern of the Jacobian matrix and its set of allowed refined inertias. The refined inertia of a matrix, which is an extension of the classical matrix inertia, is a property of its eigenvalues. A Hopf bifurcation, leading to periodic solutions, may be possible if the sign pattern of the Jacobian matrix allows a specific set of refined inertias. For most systems, we also need to consider magnitude restrictions on the entries of the Jacobian matrix that are a consequence of the particular biological model. The usefulness of sign pattern analysis to detect linear stability or the possibility of periodicity is illustrated with several biological examples, including metabolic-genetic circuits, biochemical reaction networks, predator-prey and competition systems. PMID:26092517
Photometric solution and period analysis of the contact binary system AH Cnc
Peng, Ying-Jiang; Luo, Zhi-Quan; Zhang, Xiao-Bin; Deng, Li-Cai; Wang, Kun; Tian, Jian-Feng; Yan, Zheng-Zhou; Pan, Yang; Fang, Wei-Jing; Feng, Zhong-Wen; Tang, De-Lin; Liu, Qi-Li; Sun, Jin-Jiang; Zhou, Qiang
2016-10-01
Photometric observations of AH Cnc, a W UMa-type system in the open cluster M67, were carried out by using the 50BiN telescope. About 100 h of time-series B- and V -band data were taken, based on which eight new times of light minima were determined. By applying the Wilson-Devinney method, the light curves were modeled and a revised photometric solution of the binary system was derived. We confirmed that AH Cnc is a deep contact (f = 51%), low mass-ratio (q = 0.156) system. Adopting the distance modulus derived from study of the host cluster, we have re-calculated the physical parameters of the binary system, namely the masses and radii. The masses and radii of the two components were estimated to be respectively 1.188(±0.061) M ⊙, 1.332(±0.063) R ⊙ for the primary component and 0.185(±0.032) M ⊙, 0.592(±0.051) R ⊙ for the secondary. By adding the newly derived minimum timings to all the available data, the period variations of AH Cnc were studied. This shows that the orbital period of the binary is continuously increasing at a rate of dp/dt = 4.29 × 10‑10 d yr‑1. In addition to the long-term period increase, a cyclic variation with a period of 35.26 yr was determined, which could be attributed to an unresolved tertiary component of the system.
Plasticity of the intrinsic period of the human circadian timing system.
Directory of Open Access Journals (Sweden)
Frank A J L Scheer
Full Text Available Human expeditions to Mars will require adaptation to the 24.65-h Martian solar day-night cycle (sol, which is outside the range of entrainment of the human circadian pacemaker under lighting intensities to which astronauts are typically exposed. Failure to entrain the circadian time-keeping system to the desired rest-activity cycle disturbs sleep and impairs cognitive function. Furthermore, differences between the intrinsic circadian period and Earth's 24-h light-dark cycle underlie human circadian rhythm sleep disorders, such as advanced sleep phase disorder and non-24-hour sleep-wake disorders. Therefore, first, we tested whether exposure to a model-based lighting regimen would entrain the human circadian pacemaker at a normal phase angle to the 24.65-h Martian sol and to the 23.5-h day length often required of astronauts during short duration space exploration. Second, we tested here whether such prior entrainment to non-24-h light-dark cycles would lead to subsequent modification of the intrinsic period of the human circadian timing system. Here we show that exposure to moderately bright light ( approximately 450 lux; approximately 1.2 W/m(2 for the second or first half of the scheduled wake episode is effective for entraining individuals to the 24.65-h Martian sol and a 23.5-h day length, respectively. Estimations of the circadian periods of plasma melatonin, plasma cortisol, and core body temperature rhythms collected under forced desynchrony protocols revealed that the intrinsic circadian period of the human circadian pacemaker was significantly longer following entrainment to the Martian sol as compared to following entrainment to the 23.5-h day. The latter finding of after-effects of entrainment reveals for the first time plasticity of the period of the human circadian timing system. Both findings have important implications for the treatment of circadian rhythm sleep disorders and human space exploration.
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The existence and uniqueness of a strong periodic solution of the evolution system describing geophysical flow in bounded domains of RN(N = 3, 4) are proven if external forces are periodic in time and sufficiently small.
Cortés, C
2008-01-01
We present a theoretical calibration of the RR Lyrae period-luminosity-color and period-color-color relations in the multiband uvby Stroemgren photometric system. Our theoretical work is based on calculations of synthetic horizontal branches (HBs) for four different metallicities, fully taking into account evolutionary effects for a wide range in metallicities and HB morphologies. While our results show that "pure" period-luminosity and period-color relations do not exist in the Stroemgren system, which is due to the large scatter that is brought about by evolutionary effects when the uvby bandpasses are used, they also reveal that such scatter can be almost completely taken into account by incorporating Stroemgren pseudo-color [C_0 = (u-v)_0 - (v-b)_0] terms into those equations, thus leading to tight period-luminosity-{\\em pseudo}-color (PLpsC) and period-color-{\\em pseudo}-color (PCpsC) relations. We provide the latter in the form of analytical fits, so that they can be applied with high precision even in ...
Liang, Xing; Jiang, Jifa
The asymptotic behavior of discrete type-K monotone dynamical systems and reaction-diffusion equations is investigated. The studying content includes the index theory for fixed points, permanence, global stability, convergence everywhere and coexistence. It is shown that the system has a globally asymptotically stable fixed point if every fixed point is locally asymptotically stable with respect to the face it belongs to and at this point the principal eigenvalue of the diagonal partial derivative about any component not belonging to the face is not one. A nice result presented is the sufficient and necessary conditions for the system to have a globally asymptotically stable positive fixed point. It can be used to establish the sufficient conditions for the system to persist uniformly and the convergent result for all orbits. Applications are made to time-periodic Lotka-Volterra systems with diffusion, and sufficient conditions for such systems to have a unique positive periodic solution attracting all positive initial value functions are given. For more general time-periodic type-K monotone reaction-diffusion systems with spatial homogeneity, a simple condition is given to guarantee the convergence of all positive solutions.
Spacecraft stability and control using new techniques for periodic and time-delayed systems
NAzari, Morad
This dissertation addresses various problems in spacecraft stability and control using specialized theoretical and numerical techniques for time-periodic and time-delayed systems. First, the effects of energy dissipation are considered in the dual-spin spacecraft, where the damper masses in the platform (?) and the rotor (?) cause energy loss in the system. Floquet theory is employed to obtain stability charts for different relative spin rates of the subsystem [special characters omitted] with respect to the subsystem [special characters omitted]. Further, the stability and bifurcation of delayed feedback spin stabilization of a rigid spacecraft is investigated. The spin is stabilized about the principal axis of the intermediate moment of inertia using a simple delayed feedback control law. In particular, linear stability is analyzed via the exponential-polynomial characteristic equations and then the method of multiple scales is used to obtain the normal form of the Hopf bifurcation. Next, the dynamics of a rigid spacecraft with nonlinear delayed multi-actuator feedback control are studied, where a nonlinear feedback controller using an inverse dynamics approach is sought for the controlled system to have the desired linear delayed closed-loop dynamics (CLD). Later, three linear state feedback control strategies based on Chebyshev spectral collocation and the Lyapunov Floquet transformation (LFT) are explored for regulation control of linear periodic time delayed systems. First , a delayed feedback control law with discrete delay is implemented and the stability of the closed-loop response is investigated in the parameter space of available control gains using infinite-dimensional Floquet theory. Second, the delay differential equation (DDE) is discretized into a large set of ordinary differential equations (ODEs) using the Chebyshev spectral continuous time approximation (CSCTA) and delayed feedback with distributed delay is applied. The third strategy involves
On the Eccentricity Distribution of Short-Period Single-Planet Systems
Wang, Ji
2011-01-01
We apply standard Markov chain Monte Carlo (MCMC) analysis techniques for 50 short- period, single-planet systems discovered with radial velocity technique. We develop a new method for accessing the significance of a non-zero orbital eccentricity, namely {\\Gamma} analysis, which combines frequentist bootstrap approach with Bayesian analysis of each simulated data set. We find the eccentricity estimations from {\\Gamma} analysis are generally consistent with results from both standard MCMC analysis and previous references. The {\\Gamma} method is particular useful for assessing the significance of small eccentricities. Our results suggest that the current sample size is insufficient to draw robust conclusions about the roles of tidal interaction and perturbations in shaping the eccentricity distribution of short-period single-planet systems. We use a Bayesian population analysis to show that a mixture of analytical distributions is a good approximation of the underlying eccentricity distribution. For short-perio...
Periodic-orbit theory of the number variance Σ2(L) of strongly chaotic systems
International Nuclear Information System (INIS)
We discuss the number variance Σ2(L) and the spectral form factor F(τ) of the energy levels of bound quantum systems whose classical counterparts are strongly chaotic. Exact periodic-orbit representations of Σ2(L) and F(τ) are derived which explain the breakdown of universality, i.e., the deviations from the predictions of random-matrix theory. The relation of the exact spectral form factor F(τ) to the commonly used approximation K(τ) is clarified. As an illustration the periodic-orbit representations are tested in the case of a strongly chaotic system at low and high energies including very long-range correlations up to L=700. Good agreement between 'experimental' data and theory is obtained. (orig.)
Jiang, Linqiao; Qian, Sheng-Bang; Zhang, Jia; Liu, Nianping
2015-12-01
New photometry of two different seasons for the extremely short period eclipsing binary 1SWASP J075102.16+342405.3 were performed. The two sets of derived light curves show a large difference in their shape, i.e., the 2013 light curves show big asymmetry, whereas the 2014 light curve is almost symmetric. All light curves were analysed using the 2013 version of the Wilson-Devinney (W-D) code. The obtained solutions show that 1SWASP J075102.16+342405.3 is of the A subtype W UMa contact system with an extremely high fill-out of f ≈ 96% and a high mass ratio of 0.70-0.78. Furthermore, a third light contributing to the total flux of the system was found. All these properties make the system a very special short-period source. The analysis of the 2013 light curves proved that the changes in the light curve shape are caused by magnetic activities. By means of all available times of minimum light, the variation of the orbital period was studied. It was found that the O - C diagram implies an increasing orbital period over a time span of eight years, which may be caused by the mass transfer from the less massive component to the more massive one; however, we are more inclined to say that it is only a part of a long period cyclic variation which can be explained by the light-travel time effect (LTTE) via the third body.
Non-periodic preventive maintenance with reliability thresholds for complex repairable systems
International Nuclear Information System (INIS)
In general, a non-periodic condition-based PM policy with different condition variables is often more effective than a periodic age-based policy for deteriorating complex repairable systems. In this study, system reliability is estimated and used as the condition variable, and three reliability-based PM models are then developed with consideration of different scenarios which can assist in evaluating the maintenance cost for each scenario. The proposed approach provides the optimal reliability thresholds and PM schedules in advance by which the system availability and quality can be ensured and the organizational resources can be well prepared and managed. The results of the sensitivity anlysis indicate that PM activities performed at a high reliability threshold can not only significantly improve the system availability but also efficiently extend the system lifetime, although such a PM strategy is more costly than that for a low reliabiltiy threshold. The optimal reliability threshold increases along with the number of PM activities to prevent future breakdowns caused by severe deterioration, and thus substantially reduces repair costs. - Highlights: • The PM problems for repairable deteriorating systems are formulated. • The structural properties of the proposed PM models are investigated. • The corresponding algorithms to find the optimal PM strategies are provided. • Imperfect PM activities are allowed to reduce the occurences of breakdowns. • Provide managers with insights about the critical factors in the planning stage
A high-density ternary barcode detection system employing a stable fixed-period delay method
Wakaumi, Hiroo
2011-09-01
A fixed-period delay method is proposed to increase the detection range and detection stability of a ternary barcode detection system. The system combines an envelope differential detection technique containing nonlinear filtering and a fixed-period delay to detect the barcode over a longer range and at higher scanning speeds while being simple and capable of handling a large amount of information. The system was demonstrated with its miniaturized circuit, and it was established that the detection range of the system for a minimum bar width W = 0.25 mm was 1.8 times that of the conventional count-latch envelope differential technique because of the stable delay achieved by a shift register and the noise suppression by a nonlinear filter. In addition, the system operated at a maximum scanning speed of 8.3 times that of conventional charge-coupled device cameras under the practical detection range for W = 0.3 mm. This system is expected to facilitate the real-time identification of goods on production lines and in automated warehouses.
Dynamical stability of quasi-periodic response solutions in planar conservative systems
Hanssmann, H.; Simo, Carles
2011-01-01
We study non-autonomous planar Hamiltonian or reversible vector fields that vanish at the origin. The time-dependence is quasi-periodic with strongly non-resonant frequencies. First we give a simple criterion in terms of the averaged system for the trivial solution to be dynamically stable. Then we obtain destabilizations for classes of examples where the conditions of the criterion are not satisfied. We end with possible ways to stabilize an unstable trivial solution by means of vector field...
Periodic Orbits of Radially Symmetric Keplerian-Like Systems with a Singularity
Directory of Open Access Journals (Sweden)
Shengjun Li
2016-01-01
Full Text Available We study planar radially symmetric Keplerian-like systems with repulsive singularities near the origin and with some semilinear growth near infinity. By the use of topological degree theory, we prove the existence of two distinct families of periodic orbits; one rotates around the origin with small angular momentum, and the other one rotates around the origin with both large angular momentum and large amplitude.
Modulated stochastic multiresonance in single-mode laser system without input periodic signal
Institute of Scientific and Technical Information of China (English)
梁贵云; 曹力; 吴大进
2003-01-01
The stochastic resonance phenomenon in a single-mode laser system driven by multiplicative and additive Gaussian white noises without external periodic force is studied. We find that there are multiple extrema (maximum) in the curve of the mean output laser intensity versus the logarithm of multiplicative noise level. This phenomenon reveals that the mean output laser intensity can be amplified at several values of the multiplicative noise intensity, whose peaks are likely modulated by a sinusoidal function.
Periodic wavetrains for systems of coupled nonlinear Schrödinger equations
Indian Academy of Sciences (India)
Kwok W Chow; Derek W C Lal
2001-11-01
Exact, periodic wavetrains for systems of coupled nonlinear Schrödinger equations are obtained by the Hirota bilinear method and theta functions identities. Both the bright and dark soliton regimes are treated, and the solutions involve products of elliptic functions. The validity of these solutions is veriﬁed independently by a computer algebra software. The long wave limit is studied. Physical implications will be assessed.
Analysis of Financial Performance in the Banking System in Kosovo - the Period 2006 - 2012
Skender Ahmeti; Arta Hoti; Sevdie Alshiqi – Bekteshi
2014-01-01
Through this paper we analyse the performance indicators of banks in Kosovo Banking System. According to the works of different authors worldwide, more accurate measurement of bank performance based on accounting data, in the application of coefficients leading financial banks are: Return on assets - ROA, return on equity - ROE and Cost Report to revenue - C / I. This paper describes the analysis of financial indicators for the period 2006 – 2007 – 2008 – 2009 -2010 - 2011 and 2012. The paper...
Directory of Open Access Journals (Sweden)
Dukart Adam Vilebal'dovich
2012-07-01
In the paper, the periodic mode of the system motion and the parameters of the impact absorber applicable to one-sided periodic impulses of rectangular form are examined. The structure to be protected and the absorber are simulated as a system of a single collision of masses. The impacts are accepted to be instantaneous and taken into account by means of the coefficient of restitution. The damping properties of the protected structure and the absorber are considered on the basis of the viscid friction hypothesis; therefore, the damping properties of the whole system are disproportionate. The relations identified in the course of the research are used to find the impulse frequency characteristics (IFC of the protected structure to identify the absorber parameters. The affect of duration of external impulses produced onto the IFC, characterized by the drastic increase in the amplitudes as compared to that in the case of a single impulse of the same magnitude, is the subject of research. It is proven that the maximal ordinates of IFC decrease slightly against the increase in the duration of external impulses; therefore, the efficiency of the impact absorber changes insignificantly, and it is equivalent to that of a dynamic absorber. It is noteworthy that if the duration of external impulses is under 10 % of the duration of the period, they may be replaced by instantaneous impulses.
Stability and attractivity of periodic solutions of parabolic systems with time delays
Pao, C. V.
2005-04-01
This paper is concerned with the existence, stability, and global attractivity of time-periodic solutions for a class of coupled parabolic equations in a bounded domain. The problem under consideration includes coupled system of parabolic and ordinary differential equations, and time delays may appear in the nonlinear reaction functions. Our approach to the problem is by the method of upper and lower solutions and its associated monotone iterations. The existence of time-periodic solutions is for a class of locally Lipschitz continuous reaction functions without any quasimonotone requirement using Schauder fixed point theorem, while the stability and attractivity analysis is for quasimonotone nondecreasing and mixed quasimonotone reaction functions using the monotone iterative scheme. The results for the general system are applied to the standard parabolic equations without time delay and to the corresponding ordinary differential system. Applications are also given to three Lotka-Volterra reaction diffusion model problems, and in each problem a sufficient condition on the reaction rates is obtained to ensure the stability and global attractivity of positive periodic solutions.
Stability and Fourier-series periodic solution in the binary stellar systems
Mia, Rajib
2016-01-01
In this paper, we use the restricted three body problem in the binary stellar systems, taking photogravitational effects of both the stars. The aim of this study is to investigate the motion of the infinitesimal mass in the vicinity of the Lagrangian points. We have computed semi-analytical expressions for the locations of the collinear points with the help of the perturbation technique. The stability of the triangular points is studied in stellar binary systems Kepler-34, Kepler-35, Kepler-413 and Kepler-16. To investigate the stability of the triangular points, we have obtained the expressions for critical mass which depends on the radiation of both primaries. Fourier-series method is applied to obtain periodic orbits of the infinitesimal mass around triangular points in binary stellar systems. We have obtained Fourier expansions of the periodic orbits around triangular points upto third order terms. A comparison is made between periodic orbits obtained by Fourier-series method and with Runge-Kutta integrat...
International Nuclear Information System (INIS)
This paper deals with periodic solutions of the Hamilton equation x-dot (t)=J∇x H(x(t),λ), where H element of C2,0(R2n×Rk,R) and λ element of Rk is a parameter. Theorems on global bifurcation of solutions with periods (2π)/j, j element of N, from a stationary point (x0,λ0) element of R2n×Rk are proved. ∇x2 H(x0,λ0) can be singular. However, it is assumed that the local topological degree of ∇xH(·, λ0) at x0 is nonzero. For systems satisfying ∇xH(x0, λ) = 0 for all λ element of Rk it is shown that (global) bifurcation points of solutions with periods (2π)/j can be identified with zeros of appropriate continuous functions Fj:Rk→R. If, for all λ element of Rk, ∇x2H(x0,λ)=diag(A(λ),B(λ)), where A(λ) and B(λ) are (n × n)-matrices, then Fj can be defined by Fj(λ) = det[A(λ)B(λ) − j2I]. Symmetry breaking results concerning bifurcation of solutions with different minimal periods are obtained. A geometric description of the set of bifurcation points is given. Examples of constructive application of the theorems proved to analytical and numerical investigation and visualization of the set of all bifurcation points in given domain are provided. This paper is based on a part of the author's thesis (Radzki 2005 Branching points of periodic solutions of autonomous Hamiltonian systems (Polish) PhD Thesis Nicolaus Copernicus University, Faculty of Mathematics and Computer Science, Toruń)
Ajzatskij, N I; Zakutin, V V; Reshetnyak, N G; Romasko, V P; Volkolupov, Yu Ya; Krasnogolovets, M A
2001-01-01
The study on the electron beam generation processes in the system of the magnetron guns with the secondary-emission cathodes and anodes in form of periodically positioned metallic pins is carried out. It is shown, that the beam summary current of approximately 22 A is obtained in the system, consisting of four cells, which corresponds to the quadruplicate beam current value of the one cell. The pulse capacity thereby constituted approximately 600 kW. Such beams may be applied in the multipulse microwave devices
Geometric tools for solving the FDI problem for linear periodic discrete-time systems
Longhi, Sauro; Monteriù, Andrea
2013-07-01
This paper studies the problem of detecting and isolating faults in linear periodic discrete-time systems. The aim is to design an observer-based residual generator where each residual is sensitive to one fault, whilst remaining insensitive to the other faults that can affect the system. Making use of the geometric tools, and in particular of the outer observable subspace notion, the Fault Detection and Isolation (FDI) problem is formulated and necessary and solvability conditions are given. An algorithmic procedure is described to determine the solution of the FDI problem.
Evaluation of raw milk quality in different production systems and periods of the year
Directory of Open Access Journals (Sweden)
Marcos Inácio Marcondes
2014-12-01
Full Text Available The objective of this study was to evaluate the quality of raw milk in different production systems and its variation throughout the year. The data were collected from 943 dairy farms in the South, Central-West and Central regions of the state of Minas Gerais, and in Vale do Paraíba, in the state of São Paulo, Brazil. The data were collected in the period from January 2009 to September 2011, in a total of 18,206 samples. The properties were divided into confinement, semi-confinement and extensive production systems. The evaluated factors were somatic cell count (SCC, total bacterial count (TBC and protein and fat contents. There was no effect of production system on the contents of protein, fat and SCC. Total bacterial count, however, was affected by production. Seasonal variations were found for SCC, TBC, protein and fat; the highest protein values were found from March to June; the highest fat contents were obtained from May to August; and TBC and SCC, from December to March. The production system does not interfere with the percentage of fat and protein and SCC of the milk. However, confinement systems present a better TBC content. Both month and year are factors that interfere with TBC, SCC, protein and milk fat, and the best patterns are found in the coldest periods of the year.
Markov analysis of redundant standby safety systems under periodic surveillance testing
International Nuclear Information System (INIS)
In modern applications of probabilistic safety assessment (PSA), maintenance planning and changes to technical specifications play an important role, not least due to regulatory requirements. In particular, standby safety systems under periodic surveillance testing are at the center of this issue. Since traditional PSA techniques impose limitations when complex maintenance and repair strategies are to be taken explicitly into account, we introduce continuous time Markov models to discuss various strategies for organizing repair and testing of two-train standby safety systems, which have the potential to replace traditional system models based on fault tree techniques in PSA. Besides a conventional steady state analysis of these Markov models, we provide a general numerical method which allows the calculation of the probability of exceeding allowed outage times of equipment in Markov models of safety systems, and we apply it to the models introduced in the present paper. - Highlights: • We consider Markov models of systems under periodic surveillance testing. • Besides the steady state availability we consider the probability of exceeding allowed outage times of equipment. • We provide a general method to calculate the probability of exceeding allowed outage times for Markov models
International Nuclear Information System (INIS)
To apply stochastic sensitivity function method, which can estimate the probabilistic distribution of stochastic attractors, to non-autonomous dynamical systems, a 1/N-period stroboscopic map for a periodic motion is constructed in order to discretize the continuous cycle into a discrete one. In this way, the sensitivity analysis of a cycle for discrete map can be utilized and a numerical algorithm for the stochastic sensitivity analysis of periodic solutions of non-autonomous nonlinear dynamical systems under stochastic disturbances is devised. An external excited Duffing oscillator and a parametric excited laser system are studied as examples to show the validity of the proposed method. - Highlights: • A method to analyze sensitivity of stochastic periodic attractors in non-autonomous dynamical systems is proposed. • Probabilistic distribution around periodic attractors in an external excited Φ6 Duffing system is obtained. • Probabilistic distribution around a periodic attractor in a parametric excited laser system is determined
Mixer-Duplexer-Antenna Leaky-Wave System Based on Periodic Space-Time Modulation
Taravati, Sajjad
2016-01-01
We present a mixer-duplexer-antenna leaky-wave system based on periodic space-time modulation. This system operates as a full transceiver, where the upconversion and downconversion mixing operations are accomplished via space-time transitions, the duplexing operation is induced by the nonreciprocal nature of the structure, and the radiation operation is provided by the leaky-wave nature of the wave. A rigorous electromagnetic solution is derived for the dispersion relation and field distributions. The system is implemented in the form of a spatio-temporally modulated microstrip leaky-wave structure incorporating an array of sub-wavelengthly spaced varactors modulated by a harmonic wave. In addition to the overall mixer-duplexer-antenna operation, frequency beam scanning at fixed input frequency is demonstrated as one of the interesting features of the system. A prototype is realized and demonstrated by full-wave and experimental results.
A Multiple Period Problem in Distributed Energy Management Systems Considering CO2 Emissions
Muroda, Yuki; Miyamoto, Toshiyuki; Mori, Kazuyuki; Kitamura, Shoichi; Yamamoto, Takaya
Consider a special district (group) which is composed of multiple companies (agents), and where each agent responds to an energy demand and has a CO2 emission allowance imposed. A distributed energy management system (DEMS) optimizes energy consumption of a group through energy trading in the group. In this paper, we extended the energy distribution decision and optimal planning problem in DEMSs from a single period problem to a multiple periods one. The extension enabled us to consider more realistic constraints such as demand patterns, the start-up cost, and minimum running/outage times of equipment. At first, we extended the market-oriented programming (MOP) method for deciding energy distribution to the multiple periods problem. The bidding strategy of each agent is formulated by a 0-1 mixed non-linear programming problem. Secondly, we proposed decomposing the problem into a set of single period problems in order to solve it faster. In order to decompose the problem, we proposed a CO2 emission allowance distribution method, called an EP method. We confirmed that the proposed method was able to produce solutions whose group costs were close to lower-bound group costs by computational experiments. In addition, we verified that reduction in computational time was achieved without losing the quality of solutions by using the EP method.
Guzzetti, Davide; Bosanac, Natasha; Haapala, Amanda; Howell, Kathleen C.; Folta, David C.
2016-09-01
Upcoming missions and prospective design concepts in the Earth-Moon system extensively leverage multi-body dynamics that may facilitate access to strategic locations or reduce propellant usage. To incorporate these dynamical structures into the mission design process, Purdue University and the NASA Goddard Flight Space Center have initiated the construction of a trajectory design framework to rapidly access and compare solutions from the circular restricted three-body problem. This framework, based upon a 'dynamic' catalog of periodic and quasi-periodic orbits within the Earth-Moon system, can guide an end-to-end trajectory design in an ephemeris model. In particular, the inclusion of quasi-periodic orbits further expands the design space, potentially enabling the detection of additional orbit options. To demonstrate the concept of a 'dynamic' catalog, a prototype graphical interface is developed. Strategies to characterize and represent periodic and quasi-periodic information for interactive trajectory comparison and selection are discussed. Two sample applications for formation flying near the Earth-Moon L2 point and lunar space infrastructures are explored to demonstrate the efficacy of a 'dynamic' catalog for rapid trajectory design and validity in higher-fidelity models.
Analyzing Effect of Demand Rate on Safety of Systems with Periodic Proof-tests
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
Quantitative safety assessment of safety systems plays an important role in decision making at all stages of system lifecycle, i.e., design, deployment and phase out. Most safety assessment methods consider only system parameters, such as configuration, hazard rate, coverage, repair rate, etc. along with periodic proof-tests (or inspection). Not considering demand rate will give a pessimistic safety estimate for an application with low demand rate such as nuclear power plants, chemical plants, etc. In this paper, a basic model of IEC 61508 is used. The basic model is extended to incorporate process demand and behavior of electronic- and/or computer-based system following diagnosis or proof-test. A new safety index, probability of failure on actual demand (PFAD) based on extended model and demand rate is proposed. Periodic proof-test makes the model semi-Markovian, so a piece-wise continuous time Markov chain (CTMC) based method is used to derive mean state probabilities of elementary or aggregated state. Method to determine probability of failure on demand (PFD) (IEC 61508) and PFAD based on these state probabilities are described. In example, safety indices of PFD and PFAD are compared.
Effect of intercropping period management on runoff and erosion in a maize cropping system.
Laloy, Eric; Bielders, C L
2010-01-01
The management of winter cover crops is likely to influence their performance in reducing runoff and erosion during the intercropping period that precedes spring crops but also during the subsequent spring crop. This study investigated the impact of two dates of destruction and burial of a rye (Secale cereale L.) and ryegrass (Lolium multiflorum Lam.) cover crop on runoff and erosion, focusing on a continuous silage maize (Zea mays L.) cropping system. Thirty erosion plots with various intercrop management options were monitored for 3 yr at two sites. During the intercropping period, cover crops reduced runoff and erosion by more than 94% compared with untilled, post-maize harvest plots. Rough tillage after maize harvest proved equally effective as a late sown cover crop. There was no effect of cover crop destruction and burial dates on runoff and erosion during the intercropping period, probably because rough tillage for cover crop burial compensates for the lack of soil cover. During two of the monitored maize seasons, it was observed that plots that had been covered during the previous intercropping period lost 40 to 90% less soil compared with maize plots that had been left bare during the intercropping period. The burial of an aboveground cover crop biomass in excess of 1.5 t ha(-1) was a necessary, yet not always sufficient, condition to induce a residual effect. Because of the possible beneficial residual effect of cover crop burial on erosion reduction, the sowing of a cover crop should be preferred over rough tillage after maize harvest.
Analysis of Financial Performance in the Banking System in Kosovo - the Period 2006 - 2012
Directory of Open Access Journals (Sweden)
Skender Ahmeti
2014-04-01
Full Text Available Through this paper we analyse the performance indicators of banks in Kosovo Banking System. According to the works of different authors worldwide, more accurate measurement of bank performance based on accounting data, in the application of coefficients leading financial banks are: Return on assets - ROA, return on equity - ROE and Cost Report to revenue - C / I. This paper describes the analysis of financial indicators for the period 2006 – 2007 – 2008 – 2009 -2010 - 2011 and 2012. The paper is organized as follows: - Section 2 provides literature review on the performance of banks in other countries; - Section 3 provides an analysis of the banking sector in Kosovo and macroeconomic indicators during the period analysed; - Section 4 presents the results of analysing the financial coefficients. While section 5 presents financial analysis and provides key conclusions.
The BVRI Light Curves And Period Analysis Of The Beta Lyrae System XX Leonis
Zasche, P; Svoboda, P
2007-01-01
The contact eclipsing binary system XX Leonis (P = 0.97 days, sp A8) has been analysed using the PHOEBE programme, based on the Wilson Devinney code. The BVRI light curves were obtained during spring 2006 using the 20-cm telescope and ST-7 CCD detector. The effective temperature of the primary component determined from the photometric analysis is T=(7889+/-61)K, the inclination of the orbit is i=(89.98+/-2.45)deg and the photometric mass ratio q=(0.41+/-0.01). Also the third body hypothesis was suggested, based on the period analysis using 57 minimum times and resulting the period of the third body p3= (52.96+/-0.01)yr, amplitude A=(0.057+/-0.029)d and eccentricity e=(0.79+/-0.08) which gives the minimum mass m3,min=(3.6+/-0.8)M_sun.
Necessary N-representability Constraints from Time-reversal Symmetry for Periodic Systems
Rubin, Nicholas C
2016-01-01
The variational calculation of the two-electron reduced density matrix (2-RDM) is extended to periodic molecular systems. If the 2-RDM theory is extended to the periodic case without consideration of time-reversal symmetry, however, it can yields energies that are significantly lower than the correct energies. We derive and implement linear constraints that enforce time-reversal symmetry on the 2-RDM without destroying its computationally favorable block-diagonal structure from translational invariance. Time-reversal symmetry is distinct from space-group or spin (SU(2)) symmetries which can be expressed by unitary transformations. The time-reversal symmetry constraints are demonstrated through calculations of the metallic hydrogen chain and the one-dimensional lithium hydride crystal.
Calculating residual flows through a multiple-inlet system: the conundrum of the tidal period
Duran-Matute, Matias; Gerkema, Theo
2015-11-01
The concept of residual, i.e., tidally-averaged, flows through a multiple inlet system is reappraised. The evaluation of the residual through-flow depends on the time interval over which is integrated, in other words, on how one defines the tidal period. It is demonstrated that this definition is ambiguous and that different definitions (based on, e.g., high waters, slack tides, etc.) yield very different results for the residual, also in terms of their long-term statistical properties (median and standard deviation). A basin-wide applicable method of defining the tidal period, in terms of enclosed water volume, is analyzed. We compare the different methods on the basis of high-resolution model results for the Western Dutch Wadden Sea. The multitude of tidal constituents together with wind variability creates broad distributions for the residuals, with standard deviations much larger than the mean or median residual flows.
1/1 resonant periodic orbits in three dimensional planetary systems
Antoniadou, Kyriaki I; Varvoglis, Harry
2014-01-01
We study the dynamics of a two-planet system, which evolves being in a $1/1$ mean motion resonance (co-orbital motion) with non-zero mutual inclination. In particular, we examine the existence of bifurcations of periodic orbits from the planar to the spatial case. We find that such bifurcations exist only for planetary mass ratios $\\rho=\\frac{m_2}{m_1}<0.0205$. For $\\rho$ in the interval $0<\\rho<0.0205$, we compute the generated families of spatial periodic orbits and their linear stability. These spatial families form bridges, which start and end at the same planar family. Along them the mutual planetary inclination varies. We construct maps of dynamical stability and show the existence of regions of regular orbits in phase space.
Energy Technology Data Exchange (ETDEWEB)
Jin Zhen E-mail: jinzhn@263.net; Ma Zhien; Maoan Han
2004-10-01
In this paper, we study the existence of positive periodic solutions of periodic n-species Lotka-Volterra competition systems with impulses. By using the method coincidence degree theorem, a set of easily verifiable sufficient conditions are obtained for the existence of at least one strictly positive periodic solutions. Some known results are improved and generalized.
Dynamic gene expression in the song system of zebra finches during the song learning period.
Olson, Christopher R; Hodges, Lisa K; Mello, Claudio V
2015-12-01
The brain circuitry that controls song learning and production undergoes marked changes in morphology and connectivity during the song learning period in juvenile zebra finches, in parallel to the acquisition, practice and refinement of song. Yet, the genetic programs and timing of regulatory change that establish the neuronal connectivity and plasticity during this critical learning period remain largely undetermined. To address this question, we used in situ hybridization to compare the expression patterns of a set of 30 known robust molecular markers of HVC and/or area X, major telencephalic song nuclei, between adult and juvenile male zebra finches at different ages during development (20, 35, 50 days post-hatch, dph). We found that several of the genes examined undergo substantial changes in expression within HVC or its surrounds, and/or in other song nuclei. They fit into broad patterns of regulation, including those whose expression within HVC during this period increases (COL12A1, COL 21A1, MPZL1, PVALB, and CXCR7) or decreases (e.g., KCNT2, SAP30L), as well as some that show decreased expression in the surrounding tissue with little change within song nuclei (e.g. SV2B, TAC1). These results reveal a broad range of molecular changes that occur in the song system in concert with the song learning period. Some of the genes and pathways identified are potential modulators of the developmental changes associated with the emergence of the adult properties of the song control system, and/or the acquisition of learned vocalizations in songbirds.
Zhou, Jun; Lu, Xinbiao; Qian, Huimin
2016-09-01
The paper reports interesting but unnoticed facts about irreducibility (resp., reducibility) of Flouqet factorisations and their harmonic implication in term of controllability in finite-dimensional linear continuous-time periodic (FDLCP) systems. Reducibility and irreducibility are attributed to matrix logarithm algorithms during computing Floquet factorisations in FDLCP systems, which are a pair of essential features but remain unnoticed in the Floquet theory so far. The study reveals that reducible Floquet factorisations may bring in harmonic waves variance into the Fourier analysis of FDLCP systems that in turn may alter our interpretation of controllability when the Floquet factors are used separately during controllability testing; namely, controllability interpretation discrepancy (or simply, controllability discrepancy) may occur and must be examined whenever reducible Floquet factorisations are involved. On the contrary, when irreducible Floquet factorisations are employed, controllability interpretation discrepancy can be avoided. Examples are included to illustrate such observations.
Directory of Open Access Journals (Sweden)
Theresia Lesmana
2013-11-01
Full Text Available Assessment of corporate performance can be viewed from financial aspect and nonfinancial aspect. This study attempted specifically to measure financial performance by using the DuPont system of financial analysis. DuPont system disaggregates performance into three components. They are Net Profit Margin (NPM, Return on Assets (ROA and Return on Equity (ROE. Object of this study is five largest financial institutions based on market capitalization and go public. Those five financial institutions are Bank Republik Indonesia (Persero Tbk (BBRI, Bank Central Asia Tbk (BBCA, Bank Mandiri (Persero Tbk (BMRI, Bank Negara Indonesia (Persero Tbk (BBNI and Bank Danamon Indonesia Tbk (BDMN. The financial performance of five banks was measured for three periods, from 2010 until 2012. It was found that only Bank Negara Indonesia (Persero Tbk is the best financial performance using DuPont System.
On angular momentum transfer in binary systems. [stellar orbital period change
Wilson, R. E.; Stothers, R.
1975-01-01
The maximum limit for the conversion of orbital angular momentum into rotational angular momentum of the mass-gaining component in a close binary system is derived. It is shown that this conversion process does not seriously affect the rate of orbital period change and can be neglected in computing the mass transfer rate. Integration of this limit over the entire accretion process results in a value for the maximum accumulated rotational angular momentum that is 3 to 4 times larger than that implied by the observed underluminosity of stars in such systems as Mu(1) Sco, V Pup, SX Aur, and V356 Sgr. It is suggested that shell stars and emission-line stars in binary systems may be produced when the core angular momentum is transferred into an envelope having a rotational angular momentum close to the maximum limit.-
Development Mechanism of Urban System in Rapidly Changing Period in China
Institute of Scientific and Technical Information of China (English)
DU Guoqing
2007-01-01
The purpose of this research is to investigate the socio-economic development mechanism of China's urban system in terms of spatial structure and its change. Totally 246 cities from 340 designated cities in 1985, and 488 from 640 designated cities in 1995 are selected as sample cities. And 22 attributes concerning urban features are analyzed to clarify the socio-economic characteristics and their changes in the urban system. Finally, the primary development factors are verified with the relationship of spatial structure and socio-economic characteristics. In conclusion, the socio-economic changes occurred more extremely than spatial structure changes. Furthermore, foreign investment became a major power for the development of China's urban system in the period of 1985-1995.
Shit, Anindita; Chattopadhyay, Sudip; Ray Chaudhuri, Jyotipratim
2012-06-21
We arrive at the escape rate from a metastable state for a system of Brownian particles driven periodically by a space dependent, rapidly oscillating external perturbation (with frequency ω) in one dimension (one of the most important class of nonequilibrium system). Though the problem may seem to be time-dependent, and is poised on the extreme opposite side of adiabaticity, there exists a multiple scale perturbation theory ("Kapitza window") by means of which the dynamics can be treated in terms of an effective time-independent potential that is derived as an expansion in orders of 1/ω to the order ω(-3). The resulting time-independent equation is then used to calculate the escape rate of physical systems from a metastable state induced by external monochromatic field in the moderate-to-large damping limit and to investigate the effect of ω on the resulting rate in conjunction with the thermal energy. With large value of ω, we find that the environment with moderate-to-large damping impedes the escape process of the particle while high amplitude of the periodic driving force allows the particle to cross the barrier with a large escape rate. A comparison of our theoretical expression with numerical simulation gives a satisfactory agreement. PMID:22779605
Statistics of Long Period Gas Giant Planets in Known Planetary Systems
Bryan, Marta L; Howard, Andrew W; Ngo, Henry; Batygin, Konstantin; Crepp, Justin R; Fulton, B J; Hinkley, Sasha; Isaacson, Howard; Johnson, John A; Marcy, Geoffry W; Wright, Jason T
2016-01-01
We conducted a Doppler survey at Keck combined with NIRC2 K-band AO imaging to search for massive, long-period companions to 123 known exoplanet systems with one or two planets detected using the radial velocity (RV) method. Our survey is sensitive to Jupiter mass planets out to 20 AU for a majority of stars in our sample, and we report the discovery of eight new long-period planets, in addition to 20 systems with statistically significant RV trends indicating the presence of an outer companion beyond 5 AU. We combine our RV observations with AO imaging to determine the range of allowed masses and orbital separations for these companions, and account for variations in our sensitivity to companions among stars in our sample. We estimate the total occurrence rate of companions in our sample to be 52 +/- 5% over the range 1 - 20 M_Jup and 5 - 20 AU. Our data also suggest a declining frequency for gas giant planets in these systems beyond 3-10 AU, in contrast to earlier studies that found a rising frequency for g...
The Metals in the Biological Periodic System of the Elements: Concepts and Conjectures.
Maret, Wolfgang
2016-01-05
A significant number of chemical elements are either essential for life with known functions, or present in organisms with poorly defined functional outcomes. We do not know all the essential elements with certainty and we know even less about the functions of apparently non-essential elements. In this article, I discuss a basis for a biological periodic system of the elements and that biochemistry should include the elements that are traditionally part of inorganic chemistry and not only those that are in the purview of organic chemistry. A biological periodic system of the elements needs to specify what "essential" means and to which biological species it refers. It represents a snapshot of our present knowledge and is expected to undergo further modifications in the future. An integrated approach of biometal sciences called metallomics is required to understand the interactions of metal ions, the biological functions that their chemical structures acquire in the biological system, and how their usage is fine-tuned in biological species and in populations of species with genetic variations (the variome).
Self-consistent second-order Green’s function perturbation theory for periodic systems
Energy Technology Data Exchange (ETDEWEB)
Rusakov, Alexander A., E-mail: rusakov@umich.edu; Zgid, Dominika [Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109 (United States)
2016-02-07
Despite recent advances, systematic quantitative treatment of the electron correlation problem in extended systems remains a formidable task. Systematically improvable Green’s function methods capable of quantitatively describing weak and at least qualitatively strong correlations appear as promising candidates for computational treatment of periodic systems. We present a periodic implementation of temperature-dependent self-consistent 2nd-order Green’s function (GF2) method, where the self-energy is evaluated in the basis of atomic orbitals. Evaluating the real-space self-energy in atomic orbitals and solving the Dyson equation in k-space are the key components of a computationally feasible algorithm. We apply this technique to the one-dimensional hydrogen lattice — a prototypical crystalline system with a realistic Hamiltonian. By analyzing the behavior of the spectral functions, natural occupations, and self-energies, we claim that GF2 is able to recover metallic, band insulating, and at least qualitatively Mott regimes. We observe that the iterative nature of GF2 is essential to the emergence of the metallic and Mott phases.
The Metals in the Biological Periodic System of the Elements: Concepts and Conjectures
Directory of Open Access Journals (Sweden)
Wolfgang Maret
2016-01-01
Full Text Available A significant number of chemical elements are either essential for life with known functions, or present in organisms with poorly defined functional outcomes. We do not know all the essential elements with certainty and we know even less about the functions of apparently non-essential elements. In this article, I discuss a basis for a biological periodic system of the elements and that biochemistry should include the elements that are traditionally part of inorganic chemistry and not only those that are in the purview of organic chemistry. A biological periodic system of the elements needs to specify what “essential” means and to which biological species it refers. It represents a snapshot of our present knowledge and is expected to undergo further modifications in the future. An integrated approach of biometal sciences called metallomics is required to understand the interactions of metal ions, the biological functions that their chemical structures acquire in the biological system, and how their usage is fine-tuned in biological species and in populations of species with genetic variations (the variome.
The Metals in the Biological Periodic System of the Elements: Concepts and Conjectures
Maret, Wolfgang
2016-01-01
A significant number of chemical elements are either essential for life with known functions, or present in organisms with poorly defined functional outcomes. We do not know all the essential elements with certainty and we know even less about the functions of apparently non-essential elements. In this article, I discuss a basis for a biological periodic system of the elements and that biochemistry should include the elements that are traditionally part of inorganic chemistry and not only those that are in the purview of organic chemistry. A biological periodic system of the elements needs to specify what “essential” means and to which biological species it refers. It represents a snapshot of our present knowledge and is expected to undergo further modifications in the future. An integrated approach of biometal sciences called metallomics is required to understand the interactions of metal ions, the biological functions that their chemical structures acquire in the biological system, and how their usage is fine-tuned in biological species and in populations of species with genetic variations (the variome). PMID:26742035
Solitons in PT-symmetric periodic systems with the logarithmically saturable nonlinearity
Zhan, Kaiyun; Tian, Hao; Li, Xin; Xu, Xianfeng; Jiao, Zhiyong; Jia, Yulei
2016-09-01
We report on the formation and stability of induced solitons in parity-time (PT) symmetric periodic systems with the logarithmically saturable nonlinearity. Both on-site and off-site lattice solitons exist for the self-focusing nonlinearity. The most intriguing result is that the above solitons can also be realized inside the several higher-order bands of the band structure, due to the change of nonlinear type with the soliton power. Stability analysis shows that on-site solitons are linearly stably, and off-site solitons are unstable in their existence domain.
Rousselet, Bernard
2013-01-01
We consider {\\it small solutions} of a vibrating mechanical system with smooth non-linearities for which we provide an approximate solution by using a triple scale analysis; a rigorous proof of convergence of the triple scale method is included; for the forced response, a stability result is needed in order to prove convergence in a neighbourhood of a primary resonance. The amplitude of the response with respect to the frequency forcing is described and it is related to the frequency of a free periodic vibration.
The Iterative Solution to Discrete-Time H∞ Control Problems for Periodic Systems
Directory of Open Access Journals (Sweden)
Ivan G. Ivanov
2016-03-01
Full Text Available This paper addresses the problem of solving discrete-time H ∞ control problems for periodic systems. The approach for solving such a type of equations is well known in the literature. However, the focus of our research is set on the numerical computation of the stabilizing solution. In particular, two effective methods for practical realization of the known iterative processes are described. Furthermore, a new iterative approach is investigated and applied. On the basis of numerical experiments, we compare the presented methods. A major conclusion is that the new iterative approach is faster than rest of the methods and it uses less RAM memory than other methods.
Energy Technology Data Exchange (ETDEWEB)
Kim, Jong Woo; Choi, Go Bong; Lee, Jong Min [Seoul National University, Seoul (Korea, Republic of); Suh, Jung Chul [Samchully Corporation, Seoul (Korea, Republic of)
2016-01-15
This paper proposes a Markov decision process (MDP) based approach to derive an optimal schedule of maintenance, rehabilitation and replacement of the water main system. The scheduling problem utilizes auxiliary information of a pipe such as the current state, cost, and deterioration model. The objective function and detailed algorithm of dynamic programming are modified to solve the periodic replacement problem. The optimal policy evaluated by the proposed algorithm is compared to several existing policies via Monte Carlo simulations. The proposed decision framework provides a systematic way to obtain an optimal policy.
Periodic Solution of a Nonautonomous Diffusive Food Chain System of Three Species with Time Delays
Institute of Scientific and Technical Information of China (English)
Zheng-qiu Zhang; Xian-wu Zeng; Zhi-cheng Wang
2003-01-01
By using the continuation theorem of coincidence degree theory, the existence of a positive periodic solution for a nonautonomous diffusive food chain system of three species.dx1(t)/dt = xl(t)[r1(t) - a11(t)x1(t) - a12(t)x2(t)] + D1(t)[y(t) - x1(t)],dx2 (t)/dt = x2(t)[-r2(t) + a21(t)x1(t - τ1) - a22(t)x2(t) - a23(t)x3(t)],dx3 (t)/dt = x3(t)[-r3(t) + a32(t)x2(t - τ2) - a33(t)x3(t)],dy(t)/dt = y(t)[r4(t) - a44(t)y(t)] + D2(t)[x1 (t) - y(t)],is established, where ri(t), aii(t) (i= 1, 2, 3, 4), Di(t) (i = 1, 2), a12(t), a21 (t), a23(t) and a32(t) are all positive periodic continuous functions with period w ＞ 0, τi(i = 1, 2) are positive constants.
Buying Time—The Immune System Determinants of the Incubation Period to Respiratory Viruses
Directory of Open Access Journals (Sweden)
Thomas M. Moran
2010-11-01
Full Text Available Respiratory viruses cause disease in humans characterized by an abrupt onset of symptoms. Studies in humans and animal models have shown that symptoms are not immediate and appear days or even weeks after infection. Since the initial symptoms are a manifestation of virus recognition by elements of the innate immune response, early virus replication must go largely undetected. The interval between infection and the emergence of symptoms is called the incubation period and is widely used as a clinical score. While incubation periods have been described for many virus infections the underlying mechanism for this asymptomatic phase has not been comprehensively documented. Here we review studies of the interaction between human pathogenic respiratory RNA viruses and the host with a particular emphasis on the mechanisms used by viruses to inhibit immunity. We discuss the concept of the “stealth phase”, defined as the time between infection and the earliest detectable inflammatory response. We propose that the “stealth phase” phenomenon is primarily responsible for the suppression of symptoms during the incubation period and results from viral antagonism that inhibits major pathways of the innate immune system allowing an extended time of unhindered virus replication.
Thermodynamics of Micro- and Nano-Systems Driven by Periodic Temperature Variations
Brandner, Kay; Saito, Keiji; Seifert, Udo
2015-07-01
We introduce a general framework for analyzing the thermodynamics of small systems that are driven by both a periodic temperature variation and some external parameter modulating their energy. This setup covers, in particular, periodic micro- and nano-heat engines. In a first step, we show how to express total entropy production by properly identified time-independent affinities and currents without making a linear response assumption. In linear response, kinetic coefficients akin to Onsager coefficients can be identified. Specializing to a Fokker-Planck-type dynamics, we show that these coefficients can be expressed as a sum of an adiabatic contribution and one reminiscent of a Green-Kubo expression that contains deviations from adiabaticity. Furthermore, we show that the generalized kinetic coefficients fulfill an Onsager-Casimir-type symmetry tracing back to microscopic reversibility. This symmetry allows for nonidentical off-diagonal coefficients if the driving protocols are not symmetric under time reversal. We then derive a novel constraint on the kinetic coefficients that is sharper than the second law and provides an efficiency-dependent bound on power. As one consequence, we can prove that the power vanishes at least linearly when approaching Carnot efficiency. We illustrate our general framework by explicitly working out the paradigmatic case of a Brownian heat engine realized by a colloidal particle in a time-dependent harmonic trap subject to a periodic temperature profile. This case study reveals inter alia that our new general bound on power is asymptotically tight.
Johnson, Mathew A.; Zumbrun, Kevin
2010-01-01
Extending previous results of Oh--Zumbrun and Johnson--Zumbrun, we show that spectral stability implies linearized and nonlinear stability of spatially periodic traveling-wave solutions of viscous systems of conservation laws for systems of generic type, removing a restrictive assumption that wave speed be constant to first order along the manifold of nearby periodic solutions.
Non-Linear Second-Order Periodic Systems with Non-Smooth Potential
Indian Academy of Sciences (India)
Evgenia H Papageorgiou; Nikolaos S, Papageorgiou
2004-08-01
In this paper we study second order non-linear periodic systems driven by the ordinary vector -Laplacian with a non-smooth, locally Lipschitz potential function. Our approach is variational and it is based on the non-smooth critical point theory. We prove existence and multiplicity results under general growth conditions on the potential function. Then we establish the existence of non-trivial homoclinic (to zero) solutions. Our theorem appears to be the first such result (even for smooth problems) for systems monitored by the -Laplacian. In the last section of the paper we examine the scalar non-linear and semilinear problem. Our approach uses a generalized Landesman–Lazer type condition which generalizes previous ones used in the literature. Also for the semilinear case the problem is at resonance at any eigenvalue.
Directory of Open Access Journals (Sweden)
Jan FILIPCZYK
2015-12-01
Full Text Available The increasing number of road accidents nowadays seems to by a global problem. Apart from the obvious causes of accidents, such as violation of road traffic rules by drivers and pedestrians, the drunk driving, poor quality of road infrastructure, the technical faults of vehicles should also be take into account. Reasons of technical failures can be the failure of parts, components and assemblies caused by aging, poor quality or non-observance of technological norms when they are installed. It is possible to prevent the occurrence of faults by applying warning methods, one of which is obligatory periodic technical inspection. The purpose of this article is to analyze the characteristic features of the systems of technical inspections in automotive transport used in Poland and Russia. It makes it possible to identify common features and distinctive features of systems in both countries.
International Nuclear Information System (INIS)
This paper is devoted to the numerical computation and continuation of families of heteroclinic connections between hyperbolic periodic orbits (POs) of a Hamiltonian system. We describe a method that requires the numerical continuation of a nonlinear system that involves the initial conditions of the two POs, the linear approximations of the corresponding manifolds and a point in a given Poincaré section where the unstable and stable manifolds match. The method is applied to compute families of heteroclinic orbits between planar Lyapunov POs around the collinear equilibrium points of the restricted three-body problem in different scenarios. In one of them, for the Sun–Jupiter mass parameter, we provide energy ranges for which the transition between different resonances is possible. (paper)
Quasi-periodic motions in families of dynamical systems order amidst chaos
Broer, Hendrik W; Sevryuk, Mikhail B
1996-01-01
This book is on Kolmogorov-Arnol'd-Moser theory for quasi-periodic tori in dynamical systems. It gives an up-to-date report on the role parameters play for persis- tence of such tori, typically occuring on Cantor sets of positive Hausdorff measure inside phase and parameter space. The cases with preservation of symplectic or volume forms or time-reversal symmetries are included. The concepts of Whitney-smoothness and Diophantine approximation of Cantor sets on submanifolds of Euclidean space are treated, as well as Bruno's theory on analytic continuation of tori. Partly this material is new to Western mathematicians. The reader should be familiar with dynamical systems theory, differen- tial equations and some analysis. The book is directed to researchers, but its entrance level is introductory.
Application of the Periodic Average System Model in Dam Deformation Analysis
Directory of Open Access Journals (Sweden)
Yueqian Shen
2015-01-01
Full Text Available Dams are among the most important hydraulic engineering facilities used for water supply, flood control, and hydroelectric power. Monitoring of dams is crucial since deformation might have occurred. How to obtain the deformation information and then judge the safe conditions is the key and difficult problem in dam deformation monitoring field. This paper proposes the periodic average system model and creates the concept of “settlement activity” based on the dam deformation issue. Long-term deformation monitoring data is carried out in a pumped-storage power station, this model combined with settlement activity is used to make the single point deformation analysis, and then the whole settlement activity profile is drawn by clustering analysis. Considering the cumulative settlement value of every point, the dam deformation trend is analyzed in an intuitive effect way. The analysis mode of combined single point with multipoints is realized. The results show that the key deformation information of the dam can be easily grasped by the application of the periodic average system model combined with the distribution diagram of settlement activity. And, above all, the ideas of this research provide an effective method for dam deformation analysis.
Energy Technology Data Exchange (ETDEWEB)
Song, Tae Young [Nuclear Engineering and Technology Institute, Daejeon (Korea, Republic of)
2007-07-01
At present, the 10-year Periodic Safety Review(PSR) has been performing to confirm all the aspects of safety issues for all the operating plants in compliance with domestic nuclear law of article 23, subarticle 3. For each plant, in addition, Probabilistic Safety Assessment(PSA) and Severe Accident Management Guideline(SAMG) are being implemented and revised periodically to reflect the latest safety level according to principle fulfillment of severe accident policy statement. The assessment reports, as one of outcomes from these activities, are submitted into and reviewed by domestic regulatory body. During reviewing (in-office duty) and licensing (regulatory duty) process, a large number of outcomes of which most are the formal technical reports and licensing materials, are inevitably produced. Moreover, repeated review process over the plants can make them accumulated and produce a variety of documents additionally. This circumstance motivates to develop effective tool or system for the management of these reports and related technical documents for the future use in licensing process and for subsequent plant assessments. This paper presents the development status of Safety Assessment Information System(SAIS) which manages safety-related documents of PSR, PSA and SAMG for practical use for experienced engineers in charge of these areas.
Raupach, Marc; Tonner, Ralf
2015-05-01
The development and first applications of a new periodic energy decomposition analysis (pEDA) scheme for extended systems based on the Kohn-Sham approach to density functional theory are described. The pEDA decomposes the bonding energy between two fragments (e.g., the adsorption energy of a molecule on a surface) into several well-defined terms: preparation, electrostatic, Pauli repulsion, and orbital relaxation energies. This is complemented by consideration of dispersion interactions via a pairwise scheme. One major extension toward a previous implementation [Philipsen and Baerends, J. Phys. Chem. B 110, 12470 (2006)] lies in the separate discussion of electrostatic and Pauli and the addition of a dispersion term. The pEDA presented here for an implementation based on atomic orbitals can handle restricted and unrestricted fragments for 0D to 3D systems considering periodic boundary conditions with and without the determination of fragment occupations. For the latter case, reciprocal space sampling is enabled. The new method gives comparable results to established schemes for molecular systems and shows good convergence with respect to the basis set (TZ2P), the integration accuracy, and k-space sampling. Four typical bonding scenarios for surface-adsorbate complexes were chosen to highlight the performance of the method representing insulating (CO on MgO(001)), metallic (H2 on M(001), M = Pd, Cu), and semiconducting (CO and C2H2 on Si(001)) substrates. These examples cover diverse substrates as well as bonding scenarios ranging from weakly interacting to covalent (shared electron and donor acceptor) bonding. The results presented lend confidence that the pEDA will be a powerful tool for the analysis of surface-adsorbate bonding in the future, enabling the transfer of concepts like ionic and covalent bonding, donor-acceptor interaction, steric repulsion, and others to extended systems.
Energy Technology Data Exchange (ETDEWEB)
Raupach, Marc; Tonner, Ralf, E-mail: tonner@chemie.uni-marburg.de [Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35032 Marburg (Germany)
2015-05-21
The development and first applications of a new periodic energy decomposition analysis (pEDA) scheme for extended systems based on the Kohn-Sham approach to density functional theory are described. The pEDA decomposes the bonding energy between two fragments (e.g., the adsorption energy of a molecule on a surface) into several well-defined terms: preparation, electrostatic, Pauli repulsion, and orbital relaxation energies. This is complemented by consideration of dispersion interactions via a pairwise scheme. One major extension toward a previous implementation [Philipsen and Baerends, J. Phys. Chem. B 110, 12470 (2006)] lies in the separate discussion of electrostatic and Pauli and the addition of a dispersion term. The pEDA presented here for an implementation based on atomic orbitals can handle restricted and unrestricted fragments for 0D to 3D systems considering periodic boundary conditions with and without the determination of fragment occupations. For the latter case, reciprocal space sampling is enabled. The new method gives comparable results to established schemes for molecular systems and shows good convergence with respect to the basis set (TZ2P), the integration accuracy, and k-space sampling. Four typical bonding scenarios for surface-adsorbate complexes were chosen to highlight the performance of the method representing insulating (CO on MgO(001)), metallic (H{sub 2} on M(001), M = Pd, Cu), and semiconducting (CO and C{sub 2}H{sub 2} on Si(001)) substrates. These examples cover diverse substrates as well as bonding scenarios ranging from weakly interacting to covalent (shared electron and donor acceptor) bonding. The results presented lend confidence that the pEDA will be a powerful tool for the analysis of surface-adsorbate bonding in the future, enabling the transfer of concepts like ionic and covalent bonding, donor-acceptor interaction, steric repulsion, and others to extended systems.
Predicting the onset of period-doubling bifurcations in noisy cardiac systems.
Quail, Thomas; Shrier, Alvin; Glass, Leon
2015-07-28
Biological, physical, and social systems often display qualitative changes in dynamics. Developing early warning signals to predict the onset of these transitions is an important goal. The current work is motivated by transitions of cardiac rhythms, where the appearance of alternating features in the timing of cardiac events is often a precursor to the initiation of serious cardiac arrhythmias. We treat embryonic chick cardiac cells with a potassium channel blocker, which leads to the initiation of alternating rhythms. We associate this transition with a mathematical instability, called a period-doubling bifurcation, in a model of the cardiac cells. Period-doubling bifurcations have been linked to the onset of abnormal alternating cardiac rhythms, which have been implicated in cardiac arrhythmias such as T-wave alternans and various tachycardias. Theory predicts that in the neighborhood of the transition, the system's dynamics slow down, leading to noise amplification and the manifestation of oscillations in the autocorrelation function. Examining the aggregates' interbeat intervals, we observe the oscillations in the autocorrelation function and noise amplification preceding the bifurcation. We analyze plots--termed return maps--that relate the current interbeat interval with the following interbeat interval. Based on these plots, we develop a quantitative measure using the slope of the return map to assess how close the system is to the bifurcation. Furthermore, the slope of the return map and the lag-1 autocorrelation coefficient are equal. Our results suggest that the slope and the lag-1 autocorrelation coefficient represent quantitative measures to predict the onset of abnormal alternating cardiac rhythms.
Energy pay-back period analysis of stand-alone photovoltaic systems
Energy Technology Data Exchange (ETDEWEB)
Kaldellis, J.K.; Zafirakis, D. [Lab of Soft Energy Applications and Environmental Protection, TEI Piraeus, P.O. Box 41046, Athens 12201 (Greece); Kondili, E. [Optimisation of Production Systems Lab, Mechanical Eng. Dept., TEI of Piraeus, P.O. Box 41046, Athens 12201 (Greece)
2010-07-15
The exploitation of solar energy by autonomous, photovoltaic (PV) based systems offers the opportunity for satisfying the electrification needs of numerous remote consumers worldwide in an environmentally friendly way. On the other hand, the sustainable character of these systems is strongly questioned by the energy intensity of processes involved in the various life cycle (LC) stages of the system components. Although there are several studies concerned with the estimation of the energy pay-back period (EPBP) for grid-connected systems, the same is not valid for stand-alone configurations. In this context, an integrated methodology is currently developed in order to estimate the EPBP of PV-battery (PV-Bat) configurations ensuring 100% energy autonomy. The main scope of the proposed analysis is to determine the optimum size of a corresponding system, comprised of multi-crystalline (mc-Si) PV modules and lead-acid (PbA) batteries, based on the criterion of minimum embodied energy, i.e. minimum EPBP. For this purpose, a representative case study examined considers the electrification needs of a typical remote consumer on the Island of Rhodes, Greece. According to the results obtained, the autonomous energy character of the system is reflected by the comparatively higher EPBP in comparison with the corresponding grid-connected option, nevertheless the PV-Bat configurations analyzed clearly constitute sustainable energy solutions. Finally, in order to increase the reliability of the calculation results, a sensitivity analysis is carried out, based on the variation of the input energy content data. (author)
International Nuclear Information System (INIS)
It has been shown that in reality at least two general scenarios of data structuring are possible: (a) a self-similar (SS) scenario when the measured data form an SS structure and (b) a quasi-periodic (QP) scenario when the repeated (strongly correlated) data form random sequences that are almost periodic with respect to each other. In the second case it becomes possible to describe their behavior and express a part of their randomness quantitatively in terms of the deterministic amplitude–frequency response belonging to the generalized Prony spectrum. This possibility allows us to re-examine the conventional concept of measurements and opens a new way for the description of a wide set of different data. In particular, it concerns different complex systems when the ‘best-fit’ model pretending to be the description of the data measured is absent but the barest necessity of description of these data in terms of the reduced number of quantitative parameters exists. The possibilities of the proposed approach and detection algorithm of the QP processes were demonstrated on actual data: spectroscopic data recorded for pure water and acoustic data for a test hole. The suggested methodology allows revising the accepted classification of different incommensurable and self-affine spatial structures and finding accurate interpretation of the generalized Prony spectroscopy that includes the Fourier spectroscopy as a partial case. (paper)
EVOLUTION OF STATE SECURITY SYSTEM OF THE WESTERN URALS IN REVOLUTIONARY PERIOD (1917 – EARLY 1918
Directory of Open Access Journals (Sweden)
E. A. KOBELEVA
2016-01-01
Full Text Available This article focuses on problems, related to changes that took place in 1917 – the most significant period in Russian history. During that year 3 government alternation took place: autocracy crashed and was replaced by the bourgeoisie. Provisional government collapsed and ceded power to Soviet system. It had a major impact on state security issues. Old state security institutions were dismantled; its employees suffered persecution not only in the capital cities but also in the regions, which include the Western Urals. Agencies for combating counter-revolution were established spontaneously during that period. This tendency became stronger due to the weakening of the Provisional government and lack of possibilities to influence regional political processes. In opinion of Soviet historians, the organizing processes of extraordinary commissions bore no relation with imperial-era commissions as its functions, authorities and operating methods varied dramatically. The novelty of the article resides in examining the transformation process of state security institutions in the Western Urals taken together as a composite whole during 1917 and start of 1918 opposite to the Soviet historiography.
Periodic and chaotic oscillations in a tumor and immune system interaction model with three delays
Energy Technology Data Exchange (ETDEWEB)
Bi, Ping [Department of Mathematics, Shanghai Key Laboratory of PMMP, East China Normal University, 500 Dongchuan Rd., Shanghai 200241 (China); Center for Partial Differential Equations, East China Normal University, 500 Dongchuan Rd., Shanghai 200241 (China); Ruan, Shigui, E-mail: ruan@math.miami.edu [Department of Mathematics, University of Miami, Coral Gables, Florida 33124-4250 (United States); Zhang, Xinan [School of Mathematics and Statistics, Central China Normal University, Wuhan 430079 (China)
2014-06-15
In this paper, a tumor and immune system interaction model consisted of two differential equations with three time delays is considered in which the delays describe the proliferation of tumor cells, the process of effector cells growth stimulated by tumor cells, and the differentiation of immune effector cells, respectively. Conditions for the asymptotic stability of equilibria and existence of Hopf bifurcations are obtained by analyzing the roots of a second degree exponential polynomial characteristic equation with delay dependent coefficients. It is shown that the positive equilibrium is asymptotically stable if all three delays are less than their corresponding critical values and Hopf bifurcations occur if any one of these delays passes through its critical value. Numerical simulations are carried out to illustrate the rich dynamical behavior of the model with different delay values including the existence of regular and irregular long periodic oscillations.
Many-body dispersion corrections for periodic systems: an efficient reciprocal space implementation
Bučko, Tomáš; Lebègue, Sébastien; Gould, Tim; Ángyán, János G.
2016-02-01
The energy and gradient expressions for the many-body dispersion scheme (MBD@rsSCS) of Ambrosetti et al (2014 J. Chem. Phys. 140 18A508) needed for an efficient implementation of the method for systems under periodic boundary conditions are reported. The energy is expressed as a sum of contributions from points sampled in the first Brillouin zone, in close analogy with planewave implementations of the RPA method for electrons in the dielectric matrix formulation. By avoiding the handling of large supercells, considerable computational savings can be achieved for materials with small and medium sized unit cells. The new implementation has been tested and used for geometry optimization and energy calculations of inorganic and molecular crystals, and layered materials.
International Nuclear Information System (INIS)
The theorem relating the length (L) and velocity (V) operators, that permits to compute in two alternative ways the polarizabilities of finite systems, is generalized to periodic infinite cases. The two alternative strategies have been implemented in the CRYSTAL code, that uses Gaussian type basis sets, within the CPHF and CPKS formalisms. The dielectric constant of diamond, SiC, silicon and MgO has been obtained with four different hamiltonians (HF, LDA, PBE, B3LYP). The effect of basis set and other computational parameters are discussed. It turns out that when a relatively extended basis set is used, LDA and PBE results obtained with the L and V operators nearly coincide, whereas HF and B3LYP schemes provide different results, as expected on the basis of the non-commutability of the HF-exchange and length operators
Note: Signal conditioning of a hot-film anemometer for a periodic flow rate monitoring system.
Mantovani, Federico; Tagliaferri, Cristian
2011-12-01
A flow monitoring system based on a constant temperature hot-film anemometer is presented. The device has been designed to monitor a dispensing process of extremely low quantities of adhesive material. The monitoring device presented in this paper is useful in industrial applications where exact flow speed tracking is not needed, but reliability and tolerance to parameters variability are essential. During the design of the device, problems related to the physical characteristic of the calorimetric sensor, in particular its thermal capacitance, and to the periodic nature of the monitored flow have been taken into account and suitable solutions have been implemented. The schematic representation of the monitoring device together with the experimental results obtained by monitoring fluids with different physical characteristics are presented.
Self-similarities in one-dimensional periodic and quasiperiodic systems
Odagaki, T.; Aoyama, Hideaki
1989-01-01
We find hyperinflation rules for periodic and quasiperiodic systems in one dimension which consist of two components and are characterized by a single-parameter α. Applying hyperinflation rules, we analyze the diffraction pattern and physical properties described by a class of transfer matrices in SL(2,C). We show that the diffraction pattern is self-similar in the wave-vector-α space. We also show that the product of transfer matrices has self-similar structure in its asymptotic behavior in the space spanned by α and parameters in the matrices, which gives rise to self-similarity in various physical properties such as transmission coefficient, conductivity, heat conductivity, effective impedance, and spectral diffusion. Possible experiments are also discussed.
Spin Waves in a Ferromagnetic Film with a Periodic System of Antidots
Directory of Open Access Journals (Sweden)
V.V. Kulish
2015-03-01
Full Text Available In the paper, spin waves in a thin film (composed of a uniaxial ferromagnet with a two-dimensional periodical system of antidots are studied. The film ferromagnet is considered to have the “easy axis” type. To describe such waves, the magnetostatic approximation with account for the magnetic dipole-dipole interaction, the exchange interaction and the anisotropy effects is used. For such waves, an equation for the magnetic potential is derived; for the case of remote antidots, the dispersion relation and the transverse wavenumber spectrum are found. For the case of a film thin compared to the exchange length and for the case of a film bounded by a high-conductivity metal, the longitudinal wavenumber spectrum and the frequency spectrum of such spin waves are also obtained.
[Interest in periodic health examinations for young people in the judicial system].
North, S
2003-12-01
The Centre for Health Examinations (CES) in Roche sur Yon has experience with the Periodic Health Examinations (EPS) on population groups in fragile or disadvantaged situations and young people in the process of integration. Minors followed by the Judicial Protection of the Youth (PJJ) are in a preoccupying state of health. Professionals led a working group for reflection from two institutions working in health management. This study aims to explore the representations of young people's health under the care of the judicial system in order to evaluate the pertinence of EPS in the health course of youth in the judicial correctional system. 23 semi-directed interviews allowed the team to show that if the youth have a somatic definition of health, they are nevertheless open to a comprehensive approach to health. Their parents are unavoidable reference points. The readability of the speakers in terms of mental health remains average. The resources in health documentation are under-utilised. The treating doctor remains a special partner for health. The knowledge of social rights is insufficient. The notion of risk and the need for more information concerns the areas of drunk driving, sexuality and road rage. The EPS very logically places itself in the health course of the youth. The partnership between the health and the justice systems should be constructed in the framework of a convention between the two institutions. PMID:14964014
Viveros, M P; Llorente, R; Suarez, J; Llorente-Berzal, A; López-Gallardo, M; de Fonseca, F Rodriguez
2012-01-01
This review focuses on the endocannabinoid system as a crucial player during critical periods of brain development, and how its disturbance either by early life stressful events or cannabis consumption may lead to important neuropsychiatric signs and symptoms. First we discuss the advantages and limitations of animal models within the framework of neuropsychiatric research and the crucial role of genetic and environmental factors for the establishment of vulnerable phenotypes. We are becoming aware of important sex differences that have emerged in relation to the psychobiology of cannabinoids. We will discuss sexual dimorphisms observed within the endogenous cannabinoid system, as well as those observed with exogenously administered cannabinoids. We start with how the expression of cannabinoid CB(1) receptors is regulated throughout development. Then, we discuss recent results showing how an experimental model of early maternal deprivation, which induces long-term neuropsychiatric symptoms, interacts in a sex-dependent manner with the brain endocannabinoid system during development. This is followed by a discussion of differential vulnerability to the pathological sequelae stemming from cannabinoid exposure during adolescence. Next we talk about sex differences in the interactions between cannabinoids and other drugs of abuse. Finally, we discuss the potential implications that organizational and activational actions of gonadal steroids may have in establishing and maintaining sex dependence in the neurobiological actions of cannabinoids and their interaction with stress.
LIDAR AND INS FUSION IN PERIODS OF GPS OUTAGES FOR MOBILE LASER SCANNING MAPPING SYSTEMS
Directory of Open Access Journals (Sweden)
I. Klein
2012-09-01
Full Text Available Mobile laser scanning systems are becoming an increasingly popular means to obtain 3D coverage on a large scale. To perform the mapping, the exact position of the vehicle must be known throughout the trajectory. Exact position is achieved via integration of Global Positioning Systems (GPS and Inertial Navigation Systems (INS. Yet, in urban environments, cases of complete or even partial GPS outages may occur leaving the navigation solution to rely only on the INS. The INS navigation solution degrades with time as the Inertial Measurement Unit (IMU measurements contains noise, which permeates into the navigation equations. Degradation of the position determination leads to loss of data in such segments. To circumvent such drift and its effects, we propose fusing INS with lidar data by using building edges. This detection of edges is then translated into position data, which is used as an aiding to the INS. It thereby enables the determination of the vehicle position with a satisfactory level accuracy, sufficient to perform the laser-scanning based mapping in those outage periods.
Effect of inertial mass on a linear system driven by dichotomous noise and a periodic signal
Institute of Scientific and Technical Information of China (English)
Li Peng; Nie Lin-Ru; Lü Xiu-Min; Zhang Qi-Bo
2011-01-01
A linear system driven by dichotomous noise and a periodic signal is investigated in the underdamped case.The exact expressions of output signal amplitude and signal-to-noise ratio (SNR) of the system are derived.By means of numerical calculation,the results indicate that (i) at some fixed noise intensities,the output signal amplitude with inertial mass exhibits the structure of a single peak and single valley,or even two peaks if the dichotomous noise is asymmetric; (ii) in the case of asymmetric dichotomous noise,the inertial mass can cause non-monotonic behaviour of the output signal amplitude with respect to noise intensity; (iii) the curve of SNR versus inertial mass displays a maximum in the case of asymmetric dichotomous noise,i.e.,a resonance-like phenomenon,while it decreases monotonically in the case of symmetric dichotomous noise; (iv) if the noise is symmetric,the inertial mass can induce stochastic resonance in the system.
Range-separated double-hybrid density-functional theory applied to periodic systems
Energy Technology Data Exchange (ETDEWEB)
Sansone, Giuseppe; Civalleri, Bartolomeo; Maschio, Lorenzo, E-mail: lorenzo.maschio@unito.it [Dipartimento di Chimica and NIS (Nanostructured Interfaces and Surfaces) Centre, Università di Torino, via Giuria 5, I-10125 Torino (Italy); Usvyat, Denis [Institute for Physical and Theoretical Chemistry, Universität Regensburg, Universitätsstrasse 31, D-93040 Regensburg (Germany); Toulouse, Julien [Sorbonne Universités, UPMC Univ. Paris 06, UMR 7616, Laboratoire de Chimie Théorique, F-75005 Paris (France); CNRS, UMR 7616, Laboratoire de Chimie Théorique, F-75005 Paris (France); Sharkas, Kamal [Department of Chemistry, State University of New York at Buffalo, Buffalo, New York 14260-3000 (United States)
2015-09-14
Quantum chemistry methods exploiting density-functional approximations for short-range electron-electron interactions and second-order Møller-Plesset (MP2) perturbation theory for long-range electron-electron interactions have been implemented for periodic systems using Gaussian-type basis functions and the local correlation framework. The performance of these range-separated double hybrids has been benchmarked on a significant set of systems including rare-gas, molecular, ionic, and covalent crystals. The use of spin-component-scaled MP2 for the long-range part has been tested as well. The results show that the value of μ = 0.5 bohr{sup −1} for the range-separation parameter usually used for molecular systems is also a reasonable choice for solids. Overall, these range-separated double hybrids provide a good accuracy for binding energies using basis sets of moderate sizes such as cc-pVDZ and aug-cc-pVDZ.
Large-Scale, Synoptic-Period Weather Systems in Mars' Atmosphere
Hollingsworth, Jeffery L.; Kahre, M.
2013-10-01
During late autumn through early spring, extratropical regions on Mars exhibit profound mean zonal equator-to-pole thermal contrasts associated with its waxing and waning seasonal polar ice caps. The imposition of this strong meridional temperature gradient supports intense eastward-traveling, synoptic-period weather systems (i.e., transient baroclinic/barotropic waves) within Mars' extratropical atmosphere. These disturbances grow, mature and decay within the east-west varying seasonal-mean middle and high-latitude westerly jet stream (i.e., the polar vortex) on the planet. Near the surface, such weather disturbances indicated distinctive, spiraling "comma"-shaped dust cloud structures of large scale, and scimitar-shaped dust fronts, indicative of processes associated with cyclo- and fronto-genesis. The weather systems are most intense during specific seasons on Mars, and in both hemispheres. The northern hemisphere (NH) disturbances appear to be significantly more vigorous than their counterparts in the southern hemisphere (SH). Further, the NH weather systems and accompanying frontal waves appear to have significant impacts on the transport of tracer fields (e.g., particularly dust and to some extent water species (vapor/ice) as well). Regarding dust, frontal waves appear to be key agents in the lifting, lofting, organization and transport of this atmospheric aerosol. A brief background and supporting observations of Mars' extratropical weather systems is presented. This is followed by various modeling studies (i.e., ranging from highly simplified, mechanistic and fully complex global circulation modeling investigations) that we are pursuing. In particular, transport of scalar quantities (e.g., tracers and high-order dynamically revealing diagnostic fields) are investigated. A discussion of outstanding issues and future modeling pursuits is offered related to Mars' extratropical traveling weather systems.
Periodic responses of a pulley-belt system with one-way clutch under inertia excitation
Ding, Hu
2015-09-01
The stable steady-state periodic response of a two-pulley belt drive system coupled with an accessory by a one-way clutch is presented. For the first time, the pulley-belt system is studied under double excitations. Specifically, the dual excitations consist of harmonic motion of the driving pulley and inertia excitation. The belt spans are modeled as axially moving viscoelastic beams by considering belt bending stiffness. Therefore, integro-partial-differential equations are derived for governing the transverse vibrations of the belt spans. Moreover, the transverse vibrations of the moving belt are coupled with the rotation vibrations of the pulleys by nonlinear dynamic tension. For describing the unidirectional decoupling function of the one-way device, rotation vibrations of the driven pulley and accessory are modeled as coupled piecewise ordinary differential equations. In order to eliminate the influence of the boundary of the belt spans, the non-trivial equilibriums of the pulley-belt system are numerically determined. Furthermore, A nonlinear piecewise discrete-continuous dynamical system is derived by introducing a coordinate transform. Coupled vibrations of the pulley-belt system are investigated via the Galerkin truncation. The natural frequencies of the coupled vibrations are obtained by using the fast Fourier transform. Moreover, frequency-response curves are abstracted from time histories. Therefore, resonance areas of the belt spans, the driven pulley and the accessory are presented. Furthermore, validity of the Galerkin method is examined by comparing with the differential and integral quadrature methods (DQM & IQM). By comparing the results with and without one-way device, significant damping effect of clutch on the dynamic response is discovered. Furthermore, the effects of the intensity of the driving pulley excitation and the inertia excitation are studied. Moreover, numerical results demonstrate that the two excitations interact on the steady
DEFF Research Database (Denmark)
Allen, Matthew S.; Sracic, Michael W.; Chauhan, Shashank;
2011-01-01
Many important systems, such as wind turbines, helicopters and turbomachinery, must be modeled with linear time-periodic equations of motion to correctly predict resonance phenomena. Time periodic effects in wind turbines might arise due to blade-to-blade manufacturing variations, stratification...
Institute of Scientific and Technical Information of China (English)
CHENYong; YANZhen－Ya; 等
2002-01-01
In this paper,we study the generalized coupled Hirota-Satsuma KdV system by using the new generalized transformation in homogeneous balance method.As a result,many explicit exact solutions,which contain new solitary wave solutions,periodic wave solutions,and the combined formal solitary wave solutions,and periodic wave solutions ,are obtained.
Institute of Scientific and Technical Information of China (English)
CHEN Yong; YAN Zhen-Ya; LI Biao; ZHANG Hong-Qing
2002-01-01
In this paper, we study the generalized coupled Hirota Satsuma KdV system by using the new generalizedtransformation in homogeneous balance method. As a result, many explicit exact solutions, which contain new solitarywave solutions, periodic wave solutions, and the combined formal solitary wave solutions, and periodic wave solutions,are obtained.
Institute of Scientific and Technical Information of China (English)
Cuimei ZHANG; Wencheng CHEN; Yu YANG
2006-01-01
In this paper, we study the existence and global asymptotic stability of positive periodic solutions of a delayed periodic predator-prey system with Holling Ⅱ type functional response. By use of the continuation theorem of coincidence degree theory and the method of Lyapunov function, some sufficient conditions are obtained.
Stabilization of periodic solutions in a tethered satellite system by damping injection
DEFF Research Database (Denmark)
Larsen, Martin Birkelund; Blanke, Mogens
2009-01-01
A spacecraft with electrodynamic tether orbiting the Earth will be subject to a periodic forcing term induced by the variation of the magnetic field along the orbit. The periodic forcing term leads to a family of unstable periodic solutions for a tether carrying a constant current. This paper...
Directory of Open Access Journals (Sweden)
B. M. Fonseca
2013-01-01
Full Text Available Although the detrimental effects of cannabis consumption during gestation are known for years, the vast majority of studies established a link between cannabis consumption and foetal development. The complex maternal-foetal interrelationships within the placental bed are essential for normal pregnancy, and decidua definitively contributes to the success of this process. Nevertheless, the molecular signalling network that coordinates strategies for successful decidualization and placentation are not well understood. The discovery of the endocannabinoid system highlighted new signalling mediators in various physiological processes, including reproduction. It is known that endocannabinoids present regulatory functions during blastocyst development, oviductal transport, and implantation. In addition, all the endocannabinoid machinery was found to be expressed in decidual and placental tissues. Additionally, endocannabinoid’s plasmatic levels were found to fluctuate during normal gestation and to induce decidual cell death and disturb normal placental development. Moreover, aberrant endocannabinoid signalling during the period of placental development has been associated with pregnancy disorders. It indicates the existence of a possible regulatory role for these molecules during decidualization and placentation processes, which are known to be particularly vulnerable. In this review, the influence of the endocannabinoid system in these critical processes is explored and discussed.
Short-period low-mass binary system CC Com revisited
Kose, O; Keskin, V; Ulas, B; Yakut, K
2011-01-01
In this study we determined precise orbital and physical parameters of the very short period low-mass contact binary system CC Com. The parameters are obtained by analysis of the new CCD data with the archival spectroscopic data. The physical parameters of the components derived as $M_\\textrm{c}$ = 0.717(14) $M_{\\odot}$, $M_\\textrm{h}$ = 0.378(8) $M_{\\odot}$, $R_\\textrm{c}$ = 0.708(12) $R_{\\odot}$, $R_\\textrm{h}$ = 0.530(10) $R_{\\odot}$, $L_\\textrm{c}$ = 0.138(12) $L_{\\odot}$, $L_\\textrm{h}$ = 0.085(7) $L_{\\odot}$, and the distance of the system is estimated as 64(4) pc. The times of minima obtained in this study and with those published before enable us to calculate the mass transfer rate between the components which is $1.6\\times10^{-8}$ M$_{\\odot}$yr$^{-1}$. Finally, we discuss the possible evolutionary scenario of CC Com.
The shortest-period M-dwarf eclipsing system BW3 V38
Maceroni, C; Maceroni, Carla; Rucinski, Slavek M.
1997-01-01
The photometric data for a short-period (0.1984 day) eclipsing binary V38 discovered by the OGLE micro-lensing team in Baade's W indow field BW3 have been analyzed. The de-reddened color (V-I_C)_0=2.3 and the light-curve synthesis solution of the I-filter light curve suggest a pair of strongly-distorted M-dwarfs, with parameters between those of YY Gem and CM Dra, revolving on a tightest known orbit among binaries consisting of Main Sequence stars. The primary, more massive and hotter, component maybe filling its Roche lobe. The very small amount of angular momentum in the orbital motion makes the system particularly important for studies of angular momentum loss at the faint end of the Main Sequence. Spectroscopic observations of the orbital radial velocity variations as well as of activity indicators are urgently needed for a better understanding of the angular-momentum and internal-structure evolutionary state of the system.
A first principles TDDFT framework for spin and time-resolved ARPES in periodic systems
De Giovannini, Umberto; Rubio, Angel
2016-01-01
We present a novel theoretical approach to simulate spin, time and angular-resolved photoelectron spectroscopy (ARPES) from first principles that is applicable to surfaces, thin films, few layer systems, and low-dimensional nanostructures. The method is based on a general formulation in the framework of time-dependent density functional theory (TDDFT) to describe the real time-evolution of electrons escaping from a surface under the effect of any external (arbitrary) laser field. By extending the so called t-SURFF method to periodic systems one can calculate the final photoelectron spectrum by collecting the flux of the ionization current trough an analysing surface. The resulting approach, that we named t-SURFFP, allows to describe a wide range of irradiation conditions without any assumption on the dynamics of the ionization process allowing for pump-probe simulations on an equal footing. To illustrate the wide scope of applicability of the method we present applications to graphene, mono- and bi-layer WSe$...
Viceré, Andrea; Yvert, Michel
2016-08-01
Rotating, non-axisymmetric neutron stars are expected to emit continuous gravitational waves at a nearly stable frequency. Nowadays about 2500 pulsars have been detected, thanks to their beamed electromagnetic emission, and many more of these objects should exist, whose electromagnetic beam does not include Earth and cannot be detected. The gravitational emission is not beamed, and could be accessible to gravitational observatories, even though no detection as been claimed yet. About half of the pulsars predicted to possibly emit gravitational waves in the frequency range accessible to ground-based interferometers belongs to binary systems; this is an additional complication, because the frequencies of these pulsars are Doppler-shifted due to their orbital motion, and an optimal detection strategy would require a computing power far beyond the present capabilities. We present here an approach which allows searching all-sky for such sources, over a broad range of frequencies, orbital periods and binary system eccentricities, reaching sensitivities potentially good enough to provide candidates for more sophisticated hierarchical detection methods. We test this new technique using real data taken during the first science run of Virgo, and estimating the sensitivity to a set of simulated pulsar signals.
Analysis of the ancient river system in Loulan period in Lop Nur region
Zhu, Jianfeng; Jia, Peng; Nie, Yueping
2010-09-01
The Lop Nur region is located in the east of the Tarim Basin. It has served as the strategic passage and communication hub of the Silk Road since Han Dynasty. During Wei-Jin period, the river system there was well developed and the ancient city of Loulan was bred there. In this study, GIS is used to accomplish automatic extraction of the river course in the Lop Nur region at first using ArcGIS. Then the RCI index is constituted to extract ancient river course from Landsat ETM image with band 3 and band 4. It is concluded that the north river course of Peacock River conformed before the end of the 4th century AD according to the distribution of the entire river course of the Lop Nur region. Later, the Peacock River changed its way to south to Tarim River, and flowed into Lop Nur along the direction paralleling Altun Mountain from west to east. It was the change of the river system that mainly caused the decrease in water supply around ancient city of Loulan before the end of 4th century. The ancient city of Loulan has been gradually ruined in the sand because of the absence of water supply since then.
Directory of Open Access Journals (Sweden)
Jiwei He
2007-07-01
Full Text Available In this paper, we consider a nonautonomous multispecies competition predator-prey system with Holling's type III functional response and prey supplement. It is proved that the system is uniformly persistent under some conditions. Furthermore, we show that the system has a unique positive periodic solution which is globally asymptotically stable.
Wave-breaking phenomena and global solutions for periodic two-component Dullin-Gottwald-Holm systems
Directory of Open Access Journals (Sweden)
Min Zhu
2013-02-01
Full Text Available In this article we study the initial-value problem for the periodic two-component b-family system, including a special case, when b = 2, which is referred to as the two-component Dullin-Gottwald-Holm (DGH system. We first show that the two-component b-family system can be derived from the theory of shallow-water waves moving over a linear shear flow. Then we establish several results of blow-up solutions corresponding to only wave breaking with certain initial profiles for the periodic two-component DGH system. Moreover, we determine the exact blow-up rate and lower bound of the lifespan for the system. Finally, we give a sufficient condition for the existence of the strong global solution to the periodic two-component DGH system.
Towards a Fundamental Understanding of Short Period Eclipsing Binary Systems Using Kepler Data
Prsa, Andrej
Kepler's ultra-high precision photometry is revolutionizing stellar astrophysics. We are seeing intrinsic phenomena on an unprecedented scale, and interpreting them is both a challenge and an exciting privilege. Eclipsing binary stars are of particular significance for stellar astrophysics because precise modeling leads to fundamental parameters of the orbiting components: masses, radii, temperatures and luminosities to better than 1-2%. On top of that, eclipsing binaries are ideal physical laboratories for studying other physical phenomena, such as asteroseismic properties, chromospheric activity, proximity effects, mass transfer in close binaries, etc. Because of the eclipses, the basic geometry is well constrained, but a follow-up spectroscopy is required to get the dynamical masses and the absolute scale of the system. A conjunction of Kepler photometry and ground- based spectroscopy is a treasure trove for eclipsing binary star astrophysics. This proposal focuses on a carefully selected set of 100 short period eclipsing binary stars. The fundamental goal of the project is to study the intrinsic astrophysical effects typical of short period binaries in great detail, utilizing Kepler photometry and follow-up spectroscopy to devise a robust and consistent set of modeling results. The complementing spectroscopy is being secured from 3 approved and fully funded programs: the NOAO 4-m echelle spectroscopy at Kitt Peak (30 nights; PI Prsa), the 10- m Hobby-Eberly Telescope high-resolution spectroscopy (PI Mahadevan), and the 2.5-m Sloan Digital Sky Survey III spectroscopy (PI Mahadevan). The targets are prioritized by the projected scientific yield. Short period detached binaries host low-mass (K- and M- type) components for which the mass-radius relationship is sparsely populated and still poorly understood, as the radii appear up to 20% larger than predicted by the population models. We demonstrate the spectroscopic detection viability in the secondary
Plasmonic properties of nanoparticle-film systems and periodic nanoparticle arrays
Le, Fei
In this thesis we perform theoretical investigations on the optical properties of geometrically infinite metallic nano-structures such as nanoparticle/film systems and periodic nanoparticle arrays. We apply both Plasmon Hybridization (PH) and Finite-Difference Time-Domain (FDTD) methods and we obtain quantitative agreement with experimental measurements as well as other theoretical methods such as Mie Theory and Finite Element simulation. For the nanoparticle over film structure, our research shows that the plasmonic interaction between the nanoparticle and the film is an electromagnetic analogue of the spinless Anderson-Fano model, which was used to describe the interaction of a localized electronic state with a continuous band of electronic states. Three characteristic regimes of the model are realized as the energy of the nanoparticle plasmon resonance lies above, within, or below the energy band of the surface plasmon state. These three interaction regimes are controlled by the film thickness. In the thin film limit, the plasmonic coupling between the nanoshell and the film induces a low-energy virtual state (VS) mainly composed of delocalized film, which can be further tuned as the aspect ratio of the nanoshell changes. The calculations are found to agree well with experimental measurements. Using FDTD method, we show that the electromagnetic field enhancement induced by the VS in the thin film limit can be very large and the nanoparticle/film system could serve as an ideal substrate for Surface Enhanced Raman Spectroscopy (SERS) and Tip Enhanced Raman Spectroscopy (TERS). The plasmonic properties of nanoparticle arrays are investigated using FDTD with Periodic Boundary Conditions (PBC). Our research shows that 2D hexagonal (hcp) nanoshell arrays possess ideal properties as a substrate that combines SERS and Surface Enhanced Infrared Absorption (SEIRA), with large electric field enhancements at the same spatial locations in the structure. With small
Sensitive periods for the functional specialization of the neural system for human face processing.
Röder, Brigitte; Ley, Pia; Shenoy, Bhamy H; Kekunnaya, Ramesh; Bottari, Davide
2013-10-15
The aim of the study was to identify possible sensitive phases in the development of the processing system for human faces. We tested the neural processing of faces in 11 humans who had been blind from birth and had undergone cataract surgery between 2 mo and 14 y of age. Pictures of faces and houses, scrambled versions of these pictures, and pictures of butterflies were presented while event-related potentials were recorded. Participants had to respond to the pictures of butterflies (targets) only. All participants, even those who had been blind from birth for several years, were able to categorize the pictures and to detect the targets. In healthy controls and in a group of visually impaired individuals with a history of developmental or incomplete congenital cataracts, the well-known enhancement of the N170 (negative peak around 170 ms) event-related potential to faces emerged, but a face-sensitive response was not observed in humans with a history of congenital dense cataracts. By contrast, this group showed a similar N170 response to all visual stimuli, which was indistinguishable from the N170 response to faces in the controls. The face-sensitive N170 response has been associated with the structural encoding of faces. Therefore, these data provide evidence for the hypothesis that the functional differentiation of category-specific neural representations in humans, presumably involving the elaboration of inhibitory circuits, is dependent on experience and linked to a sensitive period. Such functional specialization of neural systems seems necessary to archive high processing proficiency.
Changes in terrestrial aridity for the period 850-2080 from the Community Earth System Model
Fu, Qiang; Lin, Lei; Huang, Jianping; Feng, Song; Gettelman, Andrew
2016-03-01
This study examines changes in terrestrial aridity due to both natural and anthropogenic forcing for the period 850-2080 by analyzing the Community Earth System Model (CESM) Last Millennium Ensemble simulations for 850-2005 and the CESM Large Ensemble simulations for 1920-2080. We compare terrestrial aridity in the Medieval Warm Period (MWP) (950-1250) with that in the Little Ice Age (LIA) (1550-1850), present day (PD) (1950-2005) with the last millennium (LM) (850-1850), and the future (F8.5) (2050-2080) with the LM, to place anthropogenic changes in the context of changes due to natural forcings. The aridity index defined as the ratio of annual precipitation to potential evapotranspiration, averaged over land, becomes smaller (i.e., a drier terrestrial climate) by 0.34% for MWP versus LIA (MWP-LIA), 1.4% for PD versus LM (PD-LM), and 7.8% for F8.5 versus LM (F8.5-LM). The change of terrestrial-mean aridity in PD-LM and F8.5-LM due to anthropogenic forcing is thus 4 and 20 times of that from MWP-LIA due to natural forcing, respectively. It is shown that a drier climate in PD than LM is largely due to a decrease of precipitation while a drier climate in F8.5 than LM, and MWP than LIA, is mainly caused by an increase of temperature. The terrestrial-mean aridity change in PD-LM is, however, largely driven by greenhouse gas increases as in F8.5-LM. This is because anthropogenic aerosols have a small effect on terrestrial-mean aridity but at the same time they totally alter the attributions of aridity changes to meteorological variables by causing large negative anomalies in surface air temperature, available energy, and precipitation. Different from MWP-LIA and F8.5-LM, there are large spatial inhomogeneities in P/PET changes for PD-LM in both magnitudes and signs, caused by anthropogenic aerosols, greenhouse gases, and land surface changes. The changes of terrestrial-mean P and P - E (precipitation minus evaporation) for 850-2080 are also examined. The relative
Botelho, Luiz C L
2010-01-01
We present an illustrative application of the two famous mathematical theorems in differential topology in order to show the existence of periodic orbits with arbitrary given period for a class of hamiltonians .This result point out for a mathematical answer for the long standing problem of existence of Planetary Sistems around stars.
On the critical periods of Liénard systems with cubic restoring forces
Directory of Open Access Journals (Sweden)
Zhengdong Du
2004-01-01
show that for a weak center of type I, at most [(1/2deg(F(x]−1 local critical periods can bifurcate and the maximum number can be reached. For a weak center of type II, the maximum number of local critical periods that can bifurcate is at least [(1/4deg(F(x].
International Nuclear Information System (INIS)
The purpose of this research is to obtain the optimum sampling period for evaluating solar photovoltaic generation beforehand. For this purpose, the solar radiation was measured over 1 year at the once per a week. The effect of the sampling period on the integral error of amount of solar radiation was analyzed, and the fractal analysis of the solar radiation was carried out. As a result, the following issues were clarified. Er = 0,0117t and r = 0.00201Qa + 1.934 were obtained as a relational expressions of the sampling period (t) and the integral error (Er) in amount of solar radiation, and of the amount of solar radiation (Qa) and the sampling period (t). Upper limit in the optimum sampling period was the 236 seconds, when allowed integral error of amount of solar radiation was 3%
Meng, Xinzhu; Chen, Lansun
2006-12-21
This paper studies a non-autonomous Lotka-Volterra almost periodic predator-prey dispersal system with discrete and continuous time delays which consists of n-patches, the prey species can disperse among n-patches, but the predator species is confined to one patch and cannot disperse. By using comparison theorem and delay differential equation basic theory, we prove the system is uniformly persistent under some appropriate conditions. Further, by constructing suitable Lyapunov functional, we show that the system is globally asymptotically stable under some appropriate conditions. By using almost periodic functional hull theory, we show that the almost periodic system has a unique globally asymptotical stable strictly positive almost periodic solution. The conditions for the permanence, global stability of system and the existence, uniqueness of positive almost periodic solution depend on delays, so, time delays are "profitless". Finally, conclusions and two particular cases are given. These results are basically an extension of the known results for non-autonomous Lotka-Volterra systems.
Searching for twins of the V1309 Sco progenitor system: a selection of long-period contact binaries
Kurtenkov, Alexander
2016-01-01
The only well-studied red nova progenitor (V1309 Sco) was a contact binary with a 1.4-day period. The prospects for searching for similar systems, as well as stellar merger candidates in general, are explored in this work. The photospheric temperatures of 128 variables with periods P = 1.1 - 1.8 d classified as W UMa-type binaries are calculated using their colors listed in the SDSS catalog. A selection of 15 contact binaries with similar temperatures and periods as the V1309 Sco progenitor is thus compiled. The Kepler Eclipsing Binary Catalog is used to analyse systems with eclipse timing variations (ETV) possibly caused by changes of the orbital period. Out of the 31 systems with parabolic ETV curves listed by Conroy et al. (2014, AJ, 147, 45) two could be contact binaries with a decreasing period and, therefore, potential stellar merger candidates. Out of the 569 contact binaries in the OGLE field analysed by Kubiak et al. (2006, AcA, 56, 253) 14 systems have periods longer than 0.8 d and a statistically s...
Institute of Scientific and Technical Information of China (English)
Cheng Changjun; Fan Xiaojun
2000-01-01
The relation between the Lyapunov exponent spectrun of a periodically excited non-autono mous dynamical system and the Lyapunov exponent spectrum of the corresponding autonomous system is given and the validity of the relation is verified theoretically and computationally. A direct method for calculating the Lyapunov exponent spectrum of non-autonomous dynamical systems is suggested in this paper, which makes it more convenient to calculate the Lyapunov exponent spectrum of the dynamical system periodically excited. Following the defi nition of the Lyapunov dimension D(LA) of the autonomous system, the definition of the Lyapunov dimension Dl of the non-autonomous dynamical system is also given, and the difference be- tween them is the integer 1, namely, D(A)L - DL = 1. For a quasi-poriodically excited dynamical system, similar conclusions are formed.
Wu, Wanqin; Ye, Yuan
2009-11-01
In this paper, a class of nonautonomous Lotka-Volterra type multispecies competitive systems with weak Allee effect and delays are considered. By using Mawhin's continuation theorem of coincidence degree theory, we obtain some sufficient conditions for the existence of almost periodic solutions for the Lotka-Volterra system. On the case of no delays of Allee effects, by constructing a suitable Lyapunov function, we get a sufficient condition for the globally attractivity of the almost periodic solution for the Lotka-Volterra system. Moreover, we also present an illustrative example to show the effectiveness of our results.
Energy Technology Data Exchange (ETDEWEB)
Cheng Bitao, E-mail: chengbitao2006@126.com [College of Mathematics and Information Science, Qujing Normal University, Qujing, Yunnan 655011 (China)
2011-10-15
Highlights: > We study a class of second order Hamiltonian systems with superlinear and sublinear nonlinearity. > Some new solvable conditions of periodic orbits for the system are established. > Some new multiplicity results of periodic orbits for the system are obtained via some critical point theorems. > The methods and results are different from the past references. - Abstract: This paper is concerned with a class of second order Hamiltonian systems with superlinear and sublinear nonlinearity (P){l_brace} (table) ) where b(t) is a real function defined on [0, T], {mu} > 2 and H : [0, T] x R{sup N} {yields} R is a Caratheodory function. Some new multiplicity results of periodic orbits for the problem (P) are obtained via some critical point theorems.
Energy Technology Data Exchange (ETDEWEB)
Rothe, R.E.
1996-09-30
A series of 62 critical and critical approach experiments were performed to evaluate a possible novel means of storing large volumes of fissile solution in a critically safe configuration. This study is intended to increase safety and economy through use of such a system in commercial plants which handle fissionable materials in liquid form. The fissile solution`s concentration may equal or slightly exceed the minimum-critical-volume concentration; and experiments were performed for high-enriched uranium solution. Results should be generally applicable in a wide variety of plant situations. The method is called the `Poisoned Tube Tank` because strong neutron absorbers (neutron poisons) are placed inside periodically spaced stainless steel tubes which separate absorber material from solution, keeping the former free of contamination. Eight absorbers are investigated. Both square and triangular pitched lattice patterns are studied. Ancillary topics which closely model typical plant situations are also reported. They include the effect of removing small bundles of absorbers as might occur during inspections in a production plant. Not taking the tank out of service for these inspections would be an economic advantage. Another ancillary topic studies the effect of the presence of a significant volume of unpoisoned solution close to the Poisoned Tube Tank on the critical height. A summary of the experimental findings is that boron compounds were excellent absorbers, as expected. This was true for granular materials such as Gerstley Borate and Borax; but it was also true for the flexible solid composed of boron carbide and rubber, even though only thin sheets were used. Experiments with small bundles of absorbers intentionally removed reveal that quite reasonable tanks could be constructed that would allow a few tubes at a time to be removed from the tank for inspection without removing the tank from production service.
International Nuclear Information System (INIS)
A series of 62 critical and critical approach experiments were performed to evaluate a possible novel means of storing large volumes of fissile solution in a critically safe configuration. This study is intended to increase safety and economy through use of such a system in commercial plants which handle fissionable materials in liquid form. The fissile solution's concentration may equal or slightly exceed the minimum-critical-volume concentration; and experiments were performed for high-enriched uranium solution. Results should be generally applicable in a wide variety of plant situations. The method is called the 'Poisoned Tube Tank' because strong neutron absorbers (neutron poisons) are placed inside periodically spaced stainless steel tubes which separate absorber material from solution, keeping the former free of contamination. Eight absorbers are investigated. Both square and triangular pitched lattice patterns are studied. Ancillary topics which closely model typical plant situations are also reported. They include the effect of removing small bundles of absorbers as might occur during inspections in a production plant. Not taking the tank out of service for these inspections would be an economic advantage. Another ancillary topic studies the effect of the presence of a significant volume of unpoisoned solution close to the Poisoned Tube Tank on the critical height. A summary of the experimental findings is that boron compounds were excellent absorbers, as expected. This was true for granular materials such as Gerstley Borate and Borax; but it was also true for the flexible solid composed of boron carbide and rubber, even though only thin sheets were used. Experiments with small bundles of absorbers intentionally removed reveal that quite reasonable tanks could be constructed that would allow a few tubes at a time to be removed from the tank for inspection without removing the tank from production service
From plane waves to local Gaussians for the simulation of correlated periodic systems.
Booth, George H; Tsatsoulis, Theodoros; Chan, Garnet Kin-Lic; Grüneis, Andreas
2016-08-28
We present a simple, robust, and black-box approach to the implementation and use of local, periodic, atom-centered Gaussian basis functions within a plane wave code, in a computationally efficient manner. The procedure outlined is based on the representation of the Gaussians within a finite bandwidth by their underlying plane wave coefficients. The core region is handled within the projected augment wave framework, by pseudizing the Gaussian functions within a cutoff radius around each nucleus, smoothing the functions so that they are faithfully represented by a plane wave basis with only moderate kinetic energy cutoff. To mitigate the effects of the basis set superposition error and incompleteness at the mean-field level introduced by the Gaussian basis, we also propose a hybrid approach, whereby the complete occupied space is first converged within a large plane wave basis, and the Gaussian basis used to construct a complementary virtual space for the application of correlated methods. We demonstrate that these pseudized Gaussians yield compact and systematically improvable spaces with an accuracy comparable to their non-pseudized Gaussian counterparts. A key advantage of the described method is its ability to efficiently capture and describe electronic correlation effects of weakly bound and low-dimensional systems, where plane waves are not sufficiently compact or able to be truncated without unphysical artifacts. We investigate the accuracy of the pseudized Gaussians for the water dimer interaction, neon solid, and water adsorption on a LiH surface, at the level of second-order Møller-Plesset perturbation theory. PMID:27586908
Quasi-Periodic Long-Term Quadrature Light Variability in Early Type Interacting Binary Systems
Peters, Geraldine Joan
2015-08-01
Four years of Kepler observations have revealed a class of Algol-type binaries in which the relative brightness of the quadrature light varies from > 1 to trailing hemisphere) variables. Although L/T inequality in eclipsing binaries has been noted from ground-based photometry by several observers since the early 1950s, the regular or quasi-regular switching between maxima is new. Twenty L/T systems have so far been found in the Kepler database and at least three classes of L/T behavior have been identified. In this presentation I will give an update on the L/T phenomenon gleaned from the Kepler and K2 databases. The Kepler and K2 light curves are being analyzed with the 2015 version of the Wilson-Devinney (WD) program that includes major improvements in modeling star spots (i.e. spot motions due to drift and stellar rotation and spot growth and decay). The prototype L/T variable is WX Draconis (A8V + K0IV, P=1.80 d) which shows L/ T light variations of 2-3%. The primary is a delta Scuti star with a dominant pulsation period of 41 m. Preliminary analysis of the WX Dra data suggests that the L/T variability can be fit with either an accretion hot spot on the primary (T = 2.3 Tphot) that jumps in longitude or a magnetic cool spotted region on the secondary. If the latter model is correct the dark region must occupy at least 20% of the surface of the facing hemisphere of the secondary if it is completely black, or a larger area if not completely black. In both hot and cool spot scenarios magnetic fields must play a role in the activity. Support from NASA grants NNX11AC78G and NNX12AE44G and USC’s Women in Science and Engineering (WiSE) program is greatly appreciated.
Surface N Balances in Agricultural Crop Production Systems in China for the Period 1980-2015
Institute of Scientific and Technical Information of China (English)
SUN Bo; SHEN Run-Ping; A.F.BOUWMAN
2008-01-01
Surface nitrogen (N) balances for ChinEs crop production systems was estimated using statistical data collected from 1980 to 2004 at the national and provincial scale and from 1994 to 1999 at the county level.There was a surplus N balance throughout these periods,but the surplus was nearly stable in recent years.Projections using nonseasonal Box-Jenkins model or exponential models show that the N surplus for the total cultivated land in China was likely to increase from 142.8 kg ha-1 in 2004 to 168.6 kg ha-1 in 2015.The N balance surplus in the more developed southeastern provinces was the largest,and was slightly less in the central region,which caused the nitrate pollution in the ground water.The N surplus was much less in the western and northern provinces because of lower synthetic fertilizer inputs.The region with high N risk includes Beijing Municipality and Jiangsu,Zhejiang,Fujian,Guangdong,Hubei,and Shandong provinces for 2002-2004.The projections suggested that 15 provinces (or municipalities) in the middle and southeastern part of China except Jiangxi and Shanxi provinces would become the high-risk region by 2015.The level of economic development,transportation,and labor force condition had an important effect on the N balance surplus at the county level,but the last two factors showed remarkable impact at the provincial level.To decrease the nonpoint pollution (Npp) risk from crop production,the authors suggested to reduce the target level for national grain self-sufficiency to 90%-95% and change the regional structure of grain production by moving some of the future grain production from the high Npp risk areas of eastern China to parts of the central and western provinces where the Npp risk was much less.
From plane waves to local Gaussians for the simulation of correlated periodic systems
Booth, George H.; Tsatsoulis, Theodoros; Chan, Garnet Kin-Lic; Grüneis, Andreas
2016-08-01
We present a simple, robust, and black-box approach to the implementation and use of local, periodic, atom-centered Gaussian basis functions within a plane wave code, in a computationally efficient manner. The procedure outlined is based on the representation of the Gaussians within a finite bandwidth by their underlying plane wave coefficients. The core region is handled within the projected augment wave framework, by pseudizing the Gaussian functions within a cutoff radius around each nucleus, smoothing the functions so that they are faithfully represented by a plane wave basis with only moderate kinetic energy cutoff. To mitigate the effects of the basis set superposition error and incompleteness at the mean-field level introduced by the Gaussian basis, we also propose a hybrid approach, whereby the complete occupied space is first converged within a large plane wave basis, and the Gaussian basis used to construct a complementary virtual space for the application of correlated methods. We demonstrate that these pseudized Gaussians yield compact and systematically improvable spaces with an accuracy comparable to their non-pseudized Gaussian counterparts. A key advantage of the described method is its ability to efficiently capture and describe electronic correlation effects of weakly bound and low-dimensional systems, where plane waves are not sufficiently compact or able to be truncated without unphysical artifacts. We investigate the accuracy of the pseudized Gaussians for the water dimer interaction, neon solid, and water adsorption on a LiH surface, at the level of second-order Møller-Plesset perturbation theory.
Complex dynamics and switching transients in periodically forced Filippov prey–predator system
International Nuclear Information System (INIS)
Highlights: •We develop a Filippov prey–predator model with periodic forcing. •The sliding mode dynamics and its domain have been investigated. •The existence and stability of sliding periodic solution have been discussed. •The complex dynamics are addressed through bifurcation analyses. •Switching transients and their biological implications have been discussed. - Abstract: By employing threshold policy control (TPC) in combination with the definition of integrated pest management (IPM), a Filippov prey–predator model with periodic forcing has been proposed and studied, and the periodic forcing is affected by assuming a periodic variation in the intrinsic growth rate of the prey. This study aims to address how the periodic forcing and TPC affect the pest control. To do this, the sliding mode dynamics and sliding mode domain have been addressed firstly by using Utkin’s equivalent control method, and then the existence and stability of sliding periodic solution are investigated. Furthermore, the complex dynamics including multiple attractors coexistence, period adding sequences and chaotic solutions with respect to bifurcation parameters of forcing amplitude and economic threshold (ET) have been investigated numerically in more detail. Finally the switching transients associated with pest outbreaks and their biological implications have been discussed. Our results indicate that the sliding periodic solution could be globally stable, and consequently the prey or pest population can be controlled such that its density falls below the economic injury level (EIL). Moreover, the switching transients have both advantages and disadvantages concerning pest control, and the magnitude and frequency of switching transients depend on the initial values of both populations, forcing amplitude and ET
Tohumoğlu, Gülay
2000-01-01
A new method for the solution of nonlinear periodic systems was developed. It avoids the time domain calculations of the whole network equations. In the proposed method, by forming the augmented network as linear and nonlinear subnetworks these subnetworks are formulated in complex frequency and time domain respectively. Using spectral analysis the steady-state periodic solution of the whole nonlinear network is reached by an iterative approach. The method can be applied efficiently to weak a...
DISK-PLANETS INTERACTIONS AND THE DIVERSITY OF PERIOD RATIOS IN KEPLER'S MULTI-PLANETARY SYSTEMS
Energy Technology Data Exchange (ETDEWEB)
Baruteau, Clement; Papaloizou, John C. B., E-mail: C.Baruteau@damtp.cam.ac.uk, E-mail: J.C.B.Papaloizou@damtp.cam.ac.uk [Department of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)
2013-11-20
The Kepler mission is dramatically increasing the number of planets known in multi-planetary systems. Many adjacent planets have orbital period ratios near resonant values, with a tendency to be larger than required for exact first-order mean-motion resonances. This feature has been shown to be a natural outcome of orbital circularization of resonant planetary pairs due to star-planet tidal interactions. However, this feature holds in multi-planetary systems with periods longer than 10 days, in which tidal circularization is unlikely to provide efficient divergent evolution of the planets' orbits to explain these orbital period ratios. Gravitational interactions between planets and their parent protoplanetary disk may instead provide efficient divergent evolution. For a planet pair embedded in a disk, we show that interactions between a planet and the wake of its companion can reverse convergent migration and significantly increase the period ratio from a near-resonant value. Divergent evolution due to wake-planet interactions is particularly efficient when at least one of the planets opens a partial gap around its orbit. This mechanism could help account for the diversity of period ratios in Kepler's multiple systems from super-Earth to sub-Jovian planets with periods greater than about 10 days. Diversity is also expected for pairs of planets massive enough to merge their gap. The efficiency of wake-planet interactions is then much reduced, but convergent migration may stall with a variety of period ratios depending on the density structure in the common gap. This is illustrated for the Kepler-46 system, for which we reproduce the period ratio of Kepler-46b and c.
Energy Technology Data Exchange (ETDEWEB)
Zhang Long [College of Mathematics and System Sciences, Xinjiang University, Urumqi 830046 (China)], E-mail: longzhang_xj@sohu.com; Teng Zhidong [College of Mathematics and System Sciences, Xinjiang University, Urumqi 830046 (China)], E-mail: zhidong@xju.edu.cn
2008-12-15
In this paper, we study two species predator-prey Lotka-Volterra type dispersal system with periodic coefficients in two patches, in which both the prey and predator species can disperse between two patches. By utilizing analytic method, sufficient and realistic conditions on permanence and the existence of periodic solution are established. The theoretical results are confirmed by a special example and numerical simulations.
Scaling of Body Masses and Orbital Periods in the Solar System
Directory of Open Access Journals (Sweden)
Müller H.
2015-04-01
Full Text Available The paper shows that the sequence of sorted by value body masses of planets and largest planetoids is connected by a constant scaling exponent with the sequence of their sorted by value orbital periods.
Traveling waves and spreading speeds for time-space periodic monotone systems
Fang, Jian; Yu, Xiao; Zhao, Xiao-Qiang
2015-01-01
The theory of traveling waves and spreading speeds is developed for time-space periodic monotone semiflows with monostable structure. By using traveling waves of the associated Poincar\\'e maps in a strong sense, we establish the existence of time-space periodic traveling waves and spreading speeds. We then apply these abstract results to a two species competition reaction-advection-diffusion model. It turns out that the minimal wave speed exists and coincides with the single spreading speed f...
Hine, N D M; Haynes, P D; Skylaris, C K
2011-01-01
We present a comparison of methods for treating the electrostatic interactions of finite, isolated systems within periodic boundary conditions (PBCs), within Density Functional Theory (DFT), with particular emphasis on linear-scaling (LS) DFT. Often, PBCs are not physically realistic but are an unavoidable consequence of the choice of basis set and the efficacy of using Fourier transforms to compute the Hartree potential. In such cases the effects of PBCs on the calculations need to be avoided, so that the results obtained represent the open rather than the periodic boundary. The very large systems encountered in LS-DFT make the demands of the supercell approximation for isolated systems more difficult to manage, and we show cases where the open boundary (infinite cell) result cannot be obtained from extrapolation of calculations from periodic cells of increasing size. We discuss, implement and test three very different approaches for overcoming or circumventing the effects of PBCs: truncation of the Coulomb ...
Hayase, Saeko; Kanno, Yosuke; Watanabe, Masatoshi; Takahashi, Masahiko; Kuroda, Kazuyuki; Miyata, Hirokatsu
2013-06-11
Liquid-crystal phases consisting of cylindrical micelles of amphiphilic block copolymers and silica precursors are epitaxially built up on aligned surface micelles formed by an alkyl-PEO surfactant, Brij56, irrespective of the large difference in the intrinsic structural periodicities resulting in the formation of fully aligned mesostructured silica films with large lattice constants. Brij56 works as an alignment controlling agent on rubbing-treated polyimide through selective adsorption from a precursor solution containing the two surfactants, a block copolymer and Brij56, through strong hydrophobic interactions to form an anisotropic surface micelle structure. Aligned mesostructured silica layers with larger periodicities, which dominantly consist of block copolymers, form on these aligned surface micelles by gradually changing the vertical periodicity keeping the lateral intermicelle distance constant. This can be regarded as a kind of heteroepitaxy because the lattice constant at the surface is different from that of the bulk of the film. On the basis of this new concept, highly aligned mesostructured silica films with structural periodicities as large as 10 nm are successfully formed, which has never been achieved when the block copolymers are used alone as the structure-directing agent. The periodicity of the aligned films can precisely be controlled by an appropriate choice of block copolymers and the mixing ratio of the two surfactants, which increases the opportunity for applications of these films with highly anisotropic mesoscale structure. PMID:23721098
Hayase, Saeko; Kanno, Yosuke; Watanabe, Masatoshi; Takahashi, Masahiko; Kuroda, Kazuyuki; Miyata, Hirokatsu
2013-06-11
Liquid-crystal phases consisting of cylindrical micelles of amphiphilic block copolymers and silica precursors are epitaxially built up on aligned surface micelles formed by an alkyl-PEO surfactant, Brij56, irrespective of the large difference in the intrinsic structural periodicities resulting in the formation of fully aligned mesostructured silica films with large lattice constants. Brij56 works as an alignment controlling agent on rubbing-treated polyimide through selective adsorption from a precursor solution containing the two surfactants, a block copolymer and Brij56, through strong hydrophobic interactions to form an anisotropic surface micelle structure. Aligned mesostructured silica layers with larger periodicities, which dominantly consist of block copolymers, form on these aligned surface micelles by gradually changing the vertical periodicity keeping the lateral intermicelle distance constant. This can be regarded as a kind of heteroepitaxy because the lattice constant at the surface is different from that of the bulk of the film. On the basis of this new concept, highly aligned mesostructured silica films with structural periodicities as large as 10 nm are successfully formed, which has never been achieved when the block copolymers are used alone as the structure-directing agent. The periodicity of the aligned films can precisely be controlled by an appropriate choice of block copolymers and the mixing ratio of the two surfactants, which increases the opportunity for applications of these films with highly anisotropic mesoscale structure.
Directory of Open Access Journals (Sweden)
MoghimiHadji, EHSAN
2013-01-01
Full Text Available Reliability engineers generally have to deal with systems that consist of some components in series and others in parallel. Reliability of a series system can be calculated by multiplying the reliability of individual elements in that system. Failure rate of many deteriorating systems shows a bathtub shape curve. The aim of this paper is to find the average total cost of a series system, from a manufacturer’s point of view, during the first two phases of its life; considering optimality issues for burn-in and warranty periods. Numerical illustration is provided to show the applicability of the model.
Energy Technology Data Exchange (ETDEWEB)
Starkov, Konstantin E., E-mail: kstarkov@ipn.mx
2015-07-03
In this paper we study invariant domains with unbounded dynamics for one cosmological Hamiltonian system which is formed by the conformally coupled field; this system was introduced by Maciejewski et al. (2007). We find a few groups of conditions imposed on parameters of this system for which all trajectories are unbounded in both of time directions. Further, we present a few groups of other conditions imposed on system parameters under which we localize the invariant domain with unbounded dynamics; this domain is defined with help of bounds for values of the Hamiltonian level surface parameter. We describe one group of conditions when our system possesses two periodic orbits found explicitly. In some of rest cases we get localization bounds for compact invariant sets. - Highlights: • Equations for periodic orbits are got for many level sets. • Domains with unbounded dynamics are localized. • Localizations for compact invariant sets are obtained.
Directory of Open Access Journals (Sweden)
Alberto Herrán
2011-01-01
Full Text Available A multiproduct pipeline provides an economic way to transport large volumes of refined petroleum products over long distances. In such a pipeline, different products are pumped back−to−back without any separation device between them. The sequence and lengths of such pumping runs must be carefully selected in order to meet market demands while minimizing pipeline operational costs and satisfying several constraints. The production planning and scheduling of the products at the refinery must also be synchronized with the transportation in order to avoid the usage of the system at some peak−hour time intervals. In this paper, we propose a multi−period mixed integer nonlinear programming (MINLP model for an optimal planning and scheduling of the production and transportation of multiple petroleum products from a refinery plant connected to several depots through a single pipeline system. The objective of this work is to generalize the mixed integer linear programming (MILP formulation proposed by Cafaro and Cerdá (2004, Computers and Chemical Engineering where only a single planning period was considered and the production planning and scheduling was not part of the decision process. Numerical examples show how the use of a single period model for a given time period may lead to infeasible solutions when it is used for the upcoming periods. These examples also show how integrating production planning with the transportation and the use of a multi−period model may result in a cost saving compared to using a single−period model for each period, independently.
Where the Periodic Table of Elements Ends? Additional Explanations
Khazan, Albert
2011-03-01
Already 40 years ago, physicists claimed that the elements with number higher than 110 cannot exist. However at this day, Period 7 has been complete. Experiementalists syntesed 10 new syperheavy elements during only the last because. The method of synthesis is so finely developed that the experimentalists of Dubna tell about element No.150 as the higher limit of theTable of Elements (they do not provide a ground to the calculation). In contrast, our calculation are based neither on calculation of the stability of the electronic shells of the atoms, nor synthesis of the superheavy elements. Our caculation is based on study of the chemical processes, which give a new law of the Periodic Table (Albert Khazan. Upper Limit in Mendeleev's Periodic Table---Element No. 155. Svenska fysikarkivet, Stockholm, 2009). The core of the delusion of numerous scientists was that they, in their calculationsbased on Quantum Mechanics, initially set up the number of the elements (number of the protons) then calculated the atomic mass proceeding from the data. According to our theory, the atomic mass of the last element (411.66) should be calculated first, only then its number (155)!
Permanence and Positive Periodic Solutions of a Discrete Delay Competitive System
Directory of Open Access Journals (Sweden)
Wenjie Qin
2010-01-01
coincidence degree theory and constructing a suitable Lyapunov discrete function, sufficient conditions which guarantee the existence and global attractivity of positive periodic solutions are obtained. As an application, examples and their numerical simulations are presented to illustrate the feasibility of our main results.
Time averaged properties along unstable periodic orbits and chaotic orbits in two map systems
Directory of Open Access Journals (Sweden)
Y. Saiki
2008-08-01
Full Text Available Unstable periodic orbit (UPO recently has become a keyword in analyzing complex phenomena in geophysical fluid dynamics and space physics. In this paper, sets of UPOs in low dimensional maps are theoretically or systematically found, and time averaged properties along UPOs are studied, in relation to those of chaotic orbits.
18 CFR 301.4 - Exchange Period Average System Cost determination.
2010-04-01
... identified in paragraph (a)(3)(xii) of this section as the replacement escalator. (b) Calculation of sales...) Major resource additions and reductions and materiality thresholds. (1) During the Exchange Period... paragraph (c)(3) of this section and the materiality threshold described in paragraph (c)(4) of this...
The orbital period and system parameters of the recurrent nova T Pyx
Uthas, Helena; Steeghs, Danny
2010-01-01
T Pyx is a luminous recurrent nova that accretes at a much higher rate than is expected for its photometrically determined orbital period of about 1.8 hours. We here provide the first spectroscopic confirmation of the orbital period, P =1.829 hours (f=13.118368(11) c/d), based on time-resolved optical spectroscopy obtained at the VLT and the Magellan telescopes. We also derive an upper limit of the velocity semi-amplitude of the white dwarf, K1 = 17.9 +/- 1.6 km/s, and estimate a mass ratio of q = 0.20 +/- 0.03. If the mass of the donor star is estimated using the period-density relation and theoretical main-sequence mass-radius relation for a slightly inflated donor star, we find M2 = 0.14 +/- 0.03 Msun. This implies a mass of the primary white dwarf M1 = 0.7 +/- 0.2 Msun. If the white-dwarf mass is > 1 Msun, as classical nova models imply, the donor mass must be even higher. We therefore rule out the possibility that T Pyx has evolved beyond the period minimum for cataclysmic variables. We find that the sys...
Weed populations and crop rotations: exploring dynamics of a structured periodic system
Mertens, S.K.; Bosch, F. van den; Heesterbeek, J.A.P.
2002-01-01
The periodic growing of a certain set of crops in a prescribed order, called a crop rotation, is considered to be an important tool for managing weed populations. Nevertheless, the effects of crop rotations on weed population dynamics are not well understood. Explanations for rotation effects on wee
Existence of periodic solutions for the Lotka-Volterra type systems
Hirano, Norimichi; Rybicki, Sławomir
In this paper we prove the existence of nonstationary periodic solutions of delay Lotka-Volterra equations. In the proofs we use the S-degree due to Dylawerski et al. [G. Dylawerski, K. Geba, J. Jodel, W. Marzantowicz, An S-equivariant degree and the Fuller index, Ann. Polon. Math. 63 (1991) 243-280].
Directory of Open Access Journals (Sweden)
L. M. Sánchez Ruiz
2008-10-01
Full Text Available In signal processing, a pulse means a rapid change in the amplitude of a signal from a baseline value to a higher or lower value, followed by a rapid return to the baseline value. A square wave function may be viewed as a pulse that repeats its occurrence periodically but the return to the baseline value takes some time to happen. When these periodic functions act as inputs in dynamic systems, the standard tool commonly used to solve the associated initial value problem (IVP is Laplace transform and its inverse. We show how a computer algebra system may also provide the solution of these IVP straight forwardly by adequately introducing the periodic input.
Institute of Scientific and Technical Information of China (English)
LUO Xiang-Dong; GUO Feng; ZHOU Yu-Rong
2009-01-01
The phenomenon of stochastic resonance (SR) in an asymmetric mono-stable system subject to two external periodic forces and multiplicative and additive noise is investigated.It is shown that the signal-to-noise ratio (SNR) for the fundamental and higher harmonics is a non-monotonic function of the intensities of the multiplicative and additive noise, as well as of the system parameter.Moreover, the SNR for the fundamental harmonic decreases with the increase of the system asymmetry, while the SNR for the higher harmonics behaves non-monotonically as the system asymmetry varies.
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
By using Gaines and Mawhin's continuation theorem of coincidence degree theory and constructing Lyapunov functionals,a set of easily verifiable sufficient conditions are derived for the existence and global attractivity of a positive periodic solution to a predator-prey system with delays and impulses.
Directory of Open Access Journals (Sweden)
Yuanfu Shao
2014-01-01
Full Text Available By constructing a suitable Lyapunov functional, the global attractivity of positive periodic solutions for a delayed predator-prey system with diffusion and impulses is studied in this paper. Finally, an example and numerical analysis are given to show the effectiveness of the main results.
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
In this paper,a set of suffcient conditions which ensure the permanence of a nonlinear periodic predator-prey system with prey dispersal and predator density-independence are obtained,where the prey species can disperse among n patches,while the density-independent predator is confined to one of the patches and cannot disperse. Our results generalize some known results.
Directory of Open Access Journals (Sweden)
Kaihong Zhao
2011-04-01
Full Text Available Using Mawhin's continuation theorem of coincidence degree theory, we establish the existence of $2^{n+m}$ positive periodic solutions for a non-autonomous Lotka-Volterra network-like predator-prey system with harvesting terms. Here n and m denote the number of prey and predator species respectively. An example is given to illustrate our results.
Directory of Open Access Journals (Sweden)
Ni Hua
2012-01-01
Full Text Available With the help of the variable substitution and applying the fixed point theorem, we derive the sufficient conditions which guarantee the existence of the positive almost periodic solutions for a class of Lotka-Volterra type system. The main results improve and generalize the former corresponding results.
Institute of Scientific and Technical Information of China (English)
Lijuan Chen; Junyan Xu
2009-01-01
In this paper,a set of sufficient conditions which ensure the permanence of a nonlinear periodic predator-prey system with prey dispersal and predator density-independence are obtained,where the prey species can disperse among n patches,while the density-independent predator is confined to one of the patches and cannot disperse. Our results generalize some known results.
DEFF Research Database (Denmark)
Johansen, Søren Glud; Thorstenson, Anders
We show that well-known textbook formulae for determining the optimal base stock of the inventory system with continuous review and constant lead time can easily be extended to the case with periodic review and stochastic, sequential lead times. The provided performance measures and conditions...
DEFF Research Database (Denmark)
Johansen, Søren Glud; Thorstenson, Anders
2008-01-01
We extend well-known formulae for the optimal base stock of the inventory system with continuous review and constant lead time to the case with periodic review and stochastic, sequential lead times. Our extension uses the notion of the 'extended lead time'. The derived performance measures...
Balakin, A. B.; Murzakhanov, Z. G.; Kisun'ko, G. V.
2005-01-01
We discuss a gravitationally induced nonlinearity in hierarchic systems. We consider the generation of extremely low-frequency radio waves with a frequency of the periodic gravitational radiation; the generation is due to an induced nonlinear self-action of electromagnetic radiation in the vicinity of the gravitational-radiation source. These radio waves are a fundamentally new type of response of an electrodynamic system to gravitational radiation. That is why we here use an unconventional t...
Log-periodic oscillations in the specific heat behaviour for self-similar Ising type spin systems
Khamzin, A. A.; Nigmatullin, R. R.; Popov, I. I.; Zhelifonov, M. P.
2012-11-01
The self-similar model of spin-system of the Ising type is formulated. The thermodynamic properties of this model are considered. Analytically and numerically the specific heat of this system is calculated in the nearest neighbor approximation (only the influence of two neighboring spins was taken into account). It is shown that in temperature dependence of the specific heat the log-periodic oscillations are appeared. These oscillations are imposed on the expected power-law dependence.
The existence of periodic orbits and invariant tori for some 3-dimensional quadratic systems.
Jiang, Yanan; Han, Maoan; Xiao, Dongmei
2014-01-01
We use the normal form theory, averaging method, and integral manifold theorem to study the existence of limit cycles in Lotka-Volterra systems and the existence of invariant tori in quadratic systems in ℝ(3). PMID:24982980
Periodic solutions of a nonautonomous predator-prey system with stage structure and time delays
Xu, Rui; Wang, Zhiqiang
2006-11-01
A nonautonomous Lotka-Volterra type predator-prey model with stage structure and time delays is investigated. It is assumed in the model that the individuals in each species may belong to one of two classes: the immatures and the matures, the age to maturity is presented by a time delay, and that the immature predators do not feed on prey and do not have the ability to reproduce. By some comparison arguments we first discuss the permanence of the model. By using the continuation theorem of coincidence degree theory, sufficient conditions are derived for the existence of positive periodic solutions to the model. By means of a suitable Lyapunov functional, sufficient conditions are obtained for the uniqueness and global stability of the positive periodic solutions to the model.
Optimization of congested traffic flow in systems with a localized periodic inhomogeneity
Tomer, Elad; Safonov, Leonid; Madar, Nilly; Havlin, Shlomo
2001-01-01
We study traffic flow on roads with a localized periodic inhomogeneity such as traffic signals, using a stochastic car-following model. We find that in cases of congestion, traffic flow can be optimized by controlling the inhomogeneity's frequency. By studying the wavelength dependence of the flux in stop-and-go traffic states, and exploring their stability, we are able to explain the optimization process. A general conclusion drawn from this study is, that the fundamental diagram of traffic ...
First-order Phase Transitions in Finite Systems I: Periodic Boundary Conditions
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Igor Medved
2005-01-01
Full Text Available We briefly review rigorous results on the finite-size effect near first-order phase transitions at which a two-phase coexistence takes place. We consider a large class of statistical mechanical models in (hypercubic volumes with periodic boundary conditions at low temperatures. The results show a universal behavior of the asymptotic smoothing of the phase transition discontinuities. The determination of the transition point from
First-order Phase Transitions in Finite Systems I: Periodic Boundary Conditions
Igor Medved
2005-01-01
We briefly review rigorous results on the finite-size effect near first-order phase transitions at which a two-phase coexistence takes place. We consider a large class of statistical mechanical models in (hyper)cubic volumes with periodic boundary conditions at low temperatures. The results show a universal behavior of the asymptotic smoothing of the phase transition discontinuities. The determination of the transition point from
On the Special Role of Symmetric Periodic Orbits in a Chaotic System
Bénet, L; Papenbrock, T; Seligman, T H
1998-01-01
After early work of Henon it has become folk knowledge that symmetric periodic orbits are of particular importance. We reinforce this belief by additional studies and we further find that invariant closed symplectic submanifolds caused by discrete symmetries prove to be an important complement to the long known role of the orbits. The latter have particular importance in semi-classics. Based on the structural stability of hyperbolic horseshoes we give an argument that opens an avenue to the understanding of these facts.
The first photometric analysis and period investigation of the W UMa type binary system V1139 Cas
Li, K.; Hu, S.-M.; Guo, D.-F.; Jiang, Y.-G.; Gao, D.-Y.; Chen, X.
2015-01-01
V1139 Cas, which is a very short period W UMa type binary star, was a neglected object since its discovery. BVRI light curves of this system observed using the 1 m telescope at Weihai Observatory of Shandong University are presented and are analyzed using the Wilson-Devinney code. It is discovered that V1139 Cas is a shallow contact binary system (f=3.6%) with a mass ratio of q=1.583. By using all available times of minimum light, the orbital period variation is studied for the first time. We found that the orbital period has varied by a combination of an downward parabola and a sinusoid. The downward parabola means continuous period decrease at a rate of dP/dt=3.66×10-7 d yr-1 and may be caused by angular momentum loss via stellar wind. The sinusoidal variation with a period of 12.8 yr and a semi-amplitude of 0.0064 days can most likely be interpreted as the light travel time effect due to the existence of an unseen tertiary companion.
Chaos in driven Alfvén systems: unstable periodic orbits and chaotic saddles
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A. C.-L. Chian
2007-01-01
Full Text Available The chaotic dynamics of Alfvén waves in space plasmas governed by the derivative nonlinear Schrödinger equation, in the low-dimensional limit described by stationary spatial solutions, is studied. A bifurcation diagram is constructed, by varying the driver amplitude, to identify a number of nonlinear dynamical processes including saddle-node bifurcation, boundary crisis, and interior crisis. The roles played by unstable periodic orbits and chaotic saddles in these transitions are analyzed, and the conversion from a chaotic saddle to a chaotic attractor in these dynamical processes is demonstrated. In particular, the phenomenon of gap-filling in the chaotic transition from weak chaos to strong chaos via an interior crisis is investigated. A coupling unstable periodic orbit created by an explosion, within the gaps of the chaotic saddles embedded in a chaotic attractor following an interior crisis, is found numerically. The gap-filling unstable periodic orbits are responsible for coupling the banded chaotic saddle (BCS to the surrounding chaotic saddle (SCS, leading to crisis-induced intermittency. The physical relevance of chaos for Alfvén intermittent turbulence observed in the solar wind is discussed.
Lotka-Volterra systems in environments with randomly disordered temporal periodicity.
Naess, Arvid; Dimentberg, Michael F; Gaidai, Oleg
2008-08-01
A generalized Lotka-Volterra model for a pair of interacting populations of predators and prey is studied. The model accounts for the prey's interspecies competition and therefore is asymptotically stable, whereas its oscillatory behavior is induced by temporal variations in environmental conditions simulated by those in the prey's reproduction rate. Two models of the variations are considered, each of them combining randomness with "hidden" periodicity. The stationary joint probability density function (PDF) of the number of predators and prey is calculated numerically by the path integration (PI) method based on the use of characteristic functions and the fast Fourier transform. The numerical results match those for the asymptotic case of white-noise variations for which an analytical solution is available. Several examples are studied, with calculations of important characteristics of oscillations, for example the expected rate of up-crossings given the level of the predator number. The calculated PDFs may be of predominantly random (unimodal) or predominantly periodic nature (bimodal). Thus, the PI method has been demonstrated to be a powerful tool for studies of the dynamics of predator-prey pairs. The method captures the random oscillations as observed in nature, taking into account potential periodicity in the environmental conditions.
Lotka-Volterra systems in environments with randomly disordered temporal periodicity
Naess, Arvid; Dimentberg, Michael F.; Gaidai, Oleg
2008-08-01
A generalized Lotka-Volterra model for a pair of interacting populations of predators and prey is studied. The model accounts for the prey’s interspecies competition and therefore is asymptotically stable, whereas its oscillatory behavior is induced by temporal variations in environmental conditions simulated by those in the prey’s reproduction rate. Two models of the variations are considered, each of them combining randomness with “hidden” periodicity. The stationary joint probability density function (PDF) of the number of predators and prey is calculated numerically by the path integration (PI) method based on the use of characteristic functions and the fast Fourier transform. The numerical results match those for the asymptotic case of white-noise variations for which an analytical solution is available. Several examples are studied, with calculations of important characteristics of oscillations, for example the expected rate of up-crossings given the level of the predator number. The calculated PDFs may be of predominantly random (unimodal) or predominantly periodic nature (bimodal). Thus, the PI method has been demonstrated to be a powerful tool for studies of the dynamics of predator-prey pairs. The method captures the random oscillations as observed in nature, taking into account potential periodicity in the environmental conditions.
A Computer System for Forecasting the Threshold Period for Crop Weed Control
Institute of Scientific and Technical Information of China (English)
LI Jing-tao; ZOU Ping; GU Lin; FU Yang; CUI Hua-wei; ZHANG Xing-tao; CAI Chang-shu
2008-01-01
In this article, a model of a weed control threshold forecast system has been established, with related model solving, data checking, database setting up, and system engineering illustration. Moreover, it is tested by a software with data from a sugar cane planting experimental field in Yunnan, China. The methodology behind the detailed system analysis, design, and engineering has been discussed. The issue of how to create a dynamic data-dependent forecast model of a threshold forecast system, whose threshold changes according to the change of planting environment has been solved. Hence an effective solution has been initiated for further development on an agricultural expert system.
Johnson, Mathew A.; Zumbrun, Kevin
Extending previous results of Oh-Zumbrun and Johnson-Zumbrun, we show that spectral stability implies linearized and nonlinear stability of spatially periodic traveling wave solutions of viscous systems of conservation laws for systems of generic type, removing a restrictive assumption that wave speed be constant to first order along the manifold of nearby periodic solutions. Key to our analysis is a nonlinear cancellation estimate observed by Johnson and Zumbrun, along with a detailed understanding of the Whitham averaged system. The latter motivates a careful analysis of the Bloch perturbation expansion near zero frequency and suggests factoring out an appropriate translational modulation of the underlying wave, allowing us to derive the sharpened low-frequency estimates needed to close the nonlinear iteration arguments.
Directory of Open Access Journals (Sweden)
Junxiao Wang
2016-09-01
Full Text Available For reducing the steady state speed ripple, especially in high performance speed servo system applications, the steady state precision is more and more important for real servo systems. This paper investigates the steady state speed ripple periodic disturbance problem for a permanent magnet synchronous motor (PMSM servo system; a fuzzy adaptive repetitive controller is designed in the speed loop based on repetitive control and fuzzy information theory for reducing periodic disturbance. Firstly, the various sources of the PMSM speed ripple problem are described and analyzed. Then, the mathematical model of PMSM is given. Subsequently, a fuzzy adaptive repetitive controller based on repetitive control and fuzzy logic control is designed for the PMSM speed servo system. In addition, the system stability analysis is also deduced. Finally, the simulation and experiment implementation are respectively based on the MATLAB/Simulink and TMS320F2808 of Texas instrument company, DSP (digital signal processor hardware platform. Comparing to the proportional integral (PI controller, simulation and experimental results show that the proposed fuzzy adaptive repetitive controller has better periodic disturbance rejection ability and higher steady state precision.
Behaviour of a thermodynamic model system under time-dependent periodic boundary conditions
Energy Technology Data Exchange (ETDEWEB)
Berry, R.S. (Chicago Univ., IL (USA). Dept. of Chemistry); D' Isep, F.; Sertorio, L. (Turin Univ. (Italy). Ist. di Fisica; Istituto Nazionale di Fisica Nucleare, Turin (Italy))
A finite domain D/sub 2/ is enveloped by a finite domain D/sub 1/. The domain D/sub 1/, in turn, is in contact with two thermal baths with time-dependent periodic temperatures Tsub(s)(t) and Tsub(e)(t). We search for the best way to make T/sub 2/, the temperature field belonging to D/sub 2/, as close as possible to a predetermined constant. This can be obtained with the insertion of controlled energy sources or sinks. We study the formal approach with zero energy expenditure and the maximization problem which is implied.
Directory of Open Access Journals (Sweden)
Paulo Fortes Neto
2011-12-01
Full Text Available Education institutions are potential generators of large volumes of domestic sewage. Studies of natural systems for effluent treatment have shown good efficiency and low cost compared to traditional systems. This makes them suitable for various segments of society, including educational institutions. A characteristic shared by most educational institutions is that they have the same academic calendars that include a long period of recess when, in many cases, the flow of sewage systems drops to almost zero, causing damage to both macrophytes in sewage bed and their associated microorganisms. This study aimed to evaluate the efficiency of a wetland system in an educational institution, after the recess period. It was observed for 45 days if there were signs of natural recovery, without any intervention. After this period, 15 seedlings of Thypha sp. were planted in the sewage bed, and analyses were performed for 45 additional days. The system efficiency in reducing turbidity, NH3, NO3- and phosphorus was, respectively, 63.0%, 21.7%, 31.1% and 20.3%, and for BOD, COD and thermotolerant coliforms, the average efficiency was 46.0%, 29.7% and 44.0%, respectively. If considered only the period after planting the results improved, with the following results: turbidity = 78.2%, 38.0% = NH3, NO3- = 53.2% = 25.6% phosphorus, BOD = 66, 2% = 36.5% COD and thermotolerant coliform = 60.7%. The results demonstrated the importance of vegetation bed for the efficiency of such treatment system.
Directory of Open Access Journals (Sweden)
Mingzhan Huang
2014-01-01
Full Text Available Two predator-prey models with nonmonotonic functional response and state-dependent impulsive harvesting are formulated and analyzed. By using the geometry theory of semicontinuous dynamic system, we obtain the existence, uniqueness, and stability of the periodic solution and analyse the dynamic phenomenon of homoclinic bifurcation of the first system by choosing the harvesting rate β as control parameter. Besides, we also study the homoclinic bifurcation of the second system about parameter δ on the basis of the theory of rotated vector field. Finally, numerical simulations are presented to illustrate the results.
40 CFR 75.24 - Out-of-control periods and adjustment for system bias.
2010-07-01
... in linearity at any of three gas concentrations (low, mid-range, and high) exceeds the applicable... part. (d) When the bias test indicates that an SO2 monitor, a flow monitor, a NOX-diluent continuous emission monitoring system, a NOX concentration monitoring system used to determine NOX mass emissions,...
Baskaran, Santhi
2010-01-01
Energy consumption is a critical design issue in real-time systems, especially in battery- operated systems. Maintaining high performance, while extending the battery life between charges is an interesting challenge for system designers. Dynamic Voltage Scaling (DVS) allows a processor to dynamically change speed and voltage at run time, thereby saving energy by spreading run cycles into idle time. Knowing when to use full power and when not, requires the cooperation of the operating system scheduler. Usually, higher processor voltage and frequency leads to higher system throughput while energy reduction can be obtained using lower voltage and frequency. Instead of lowering processor voltage and frequency as much as possible, energy efficient real-time scheduling adjusts voltage and frequency according to some optimization criteria, such as low energy consumption or high throughput, while it meets the timing constraints of the real-time tasks. As the quantity and functional complexity of battery powered porta...
Jiang, Tian-Yu; Li, Li-Fang; Han, Zhan-Wen; Jiang, Deng-Kai
2010-04-01
The first complete charge-coupled device (CCD) light curves in B and V passbands of a neglected contact binary system, CW Cassiopeiae (CW Cas), are presented. They were analyzed simultaneously by using the Wilson and Devinney (WD) code (1971, ApJ, 166, 605). The photometric solution indicates that CW Cas is a W-type W UMa system with a mass ratio of m2/m1 2.234, and that it is in a marginal contact state with a contact degree of ˜6.5% and a relatively large temperature difference of ˜327K between its two components. Based on the minimum times collected from the literature, together with the new ones obtained in this study, the orbital period changes of CW Cas were investigated in detail. It was found that a periodical variation overlaps with a secular period decrease in its orbital period. The long-term period decrease with a rate of dP/dt = -3.44 × 10-8d yr-1 can be interpreted either by mass transfer from the more-massive component to the less-massive with a rate of dm2/dt = -3.6 × 10-8M⊙ yr-1, or by mass and angular-momentum losses through magnetic braking due to a magnetic stellar wind. A low-amplitude cyclic variation with a period of T = 63.7 yr might be caused by the light-time effect due to the presence of a third body.
Santos, N C; Faria, J P; Rey, J; Correia, A C M; Laskar, J; Udry, S; Adibekyan, V; Bouchy, F; Delgado-Mena, E; Melo, C; Dumusque, X; Hébrard, G; Lovis, C; Mayor, M; Montalto, M; Mortier, A; Pepe, F; Figueira, P; Sahlmann, J; Ségransan, D; Sousa, S G
2016-01-01
With about 2000 extrasolar planets confirmed, the results show that planetary systems have a whole range of unexpected properties. We present a full investigation of the HD219828 system, a bright metal-rich star for which a hot neptune has previously been detected. We used a set of HARPS, SOPHIE, and ELODIE radial velocities to search for the existence of orbiting companions to HD219828. A dynamical analysis is also performed to study the stability of the system and to constrain the orbital parameters and planet masses. We announce the discovery of a long period (P=13.1years) massive (msini=15.1MJup) companion (HD219828c) in a very eccentric orbit (e=0.81). The same data confirms the existence of a hot-neptune, HD219828b, with a minimum mass of 21 MEarth and a period of 3.83days. The dynamical analysis shows that the system is stable. The HD219828 system is extreme and unique in several aspects. First, among all known exoplanet systems it presents an unusually high mass ratio. We also show that systems like H...
Hine, Nicholas D M; Dziedzic, Jacek; Haynes, Peter D; Skylaris, Chris-Kriton
2011-11-28
We present a comparison of methods for treating the electrostatic interactions of finite, isolated systems within periodic boundary conditions (PBCs), within density functional theory (DFT), with particular emphasis on linear-scaling (LS) DFT. Often, PBCs are not physically realistic but are an unavoidable consequence of the choice of basis set and the efficacy of using Fourier transforms to compute the Hartree potential. In such cases the effects of PBCs on the calculations need to be avoided, so that the results obtained represent the open rather than the periodic boundary. The very large systems encountered in LS-DFT make the demands of the supercell approximation for isolated systems more difficult to manage, and we show cases where the open boundary (infinite cell) result cannot be obtained from extrapolation of calculations from periodic cells of increasing size. We discuss, implement, and test three very different approaches for overcoming or circumventing the effects of PBCs: truncation of the Coulomb interaction combined with padding of the simulation cell, approaches based on the minimum image convention, and the explicit use of open boundary conditions (OBCs). We have implemented these approaches in the ONETEP LS-DFT program and applied them to a range of systems, including a polar nanorod and a protein. We compare their accuracy, complexity, and rate of convergence with simulation cell size. We demonstrate that corrective approaches within PBCs can achieve the OBC result more efficiently and accurately than pure OBC approaches.
Hine, Nicholas D. M.; Dziedzic, Jacek; Haynes, Peter D.; Skylaris, Chris-Kriton
2011-11-01
We present a comparison of methods for treating the electrostatic interactions of finite, isolated systems within periodic boundary conditions (PBCs), within density functional theory (DFT), with particular emphasis on linear-scaling (LS) DFT. Often, PBCs are not physically realistic but are an unavoidable consequence of the choice of basis set and the efficacy of using Fourier transforms to compute the Hartree potential. In such cases the effects of PBCs on the calculations need to be avoided, so that the results obtained represent the open rather than the periodic boundary. The very large systems encountered in LS-DFT make the demands of the supercell approximation for isolated systems more difficult to manage, and we show cases where the open boundary (infinite cell) result cannot be obtained from extrapolation of calculations from periodic cells of increasing size. We discuss, implement, and test three very different approaches for overcoming or circumventing the effects of PBCs: truncation of the Coulomb interaction combined with padding of the simulation cell, approaches based on the minimum image convention, and the explicit use of open boundary conditions (OBCs). We have implemented these approaches in the ONETEP LS-DFT program and applied them to a range of systems, including a polar nanorod and a protein. We compare their accuracy, complexity, and rate of convergence with simulation cell size. We demonstrate that corrective approaches within PBCs can achieve the OBC result more efficiently and accurately than pure OBC approaches.
Safety characteristics of non-lithium battery systems. Final report for period ending FY84
Energy Technology Data Exchange (ETDEWEB)
Murphy, R.M.; Bis, R.F.
1984-07-01
A study was conducted to determine the safety characteristics for both primary and secondary non-lithium battery systems. Of particular interest was the behavior of these battery systems when subjected to the electrical and thermal-abuse testing procedures of NAVSEAINST 9310.1A (i.e., short circuit, forced overdischarge, and incineration). Also included are the safety/hazard characteristics associated with charging primary batteries and overcharging secondary batteries. This report also summarizes the manufacture, electrical performance, failure mechanisms, self-discharge, and applications for twenty-two primary and nineteen secondary battery systems.
Directory of Open Access Journals (Sweden)
Anca Visinescu
2011-04-01
Full Text Available Using the multiple scales method, the interaction between two bright and one dark solitons is studied. Provided that a long wave-short wave resonance condition is satisfied, the two-component Zakharov-Yajima-Oikawa (ZYO completely integrable system is obtained. By using a Madelung fluid description, the one-soliton solutions of the corresponding ZYO system are determined. Furthermore, a discussion on the interaction between one bright and two dark solitons is presented. In particular, this problem is reduced to solve a one-component ZYO system in the resonance conditions.
Post-Keplerian corrections to the orbital periods of a two-body system and their measurability
Iorio, L.
2016-08-01
The orbital motion of a binary system is characterized by various characteristic temporal intervals which, by definition, are different from each other: the draconitic, anomalistic and sidereal periods Tdra, Tano, Tsid. They all coincide in the Keplerian case. Such a degeneracy is removed, in general, when a post-Keplerian acceleration is present. We analytically work out the corrections T(pK) to such otherwise Keplerian periods which are induced by general relativity (Schwarzschild and Lense-Thirring) and, at the Newtonian level, by the quadrupole J2 of the primary. In many astronomical and astrophysical systems, like exoplanets, one of the most accurately determined quantities is just the time span Texp characterizing the orbital revolution, which is often measured independently with different techniques like the transit photometry and the radial velocities. Thus, our results could be useful, in principle, to either constrain the physical properties of the central body and/or perform new tests of general relativity, especially when no other standard observables like, e.g. the orbital precessions are accessible to observations. The difference ΔT of two independently measured periods would cancel out the common Keplerian term TK leaving just a post-Keplerian correction. Furthermore, by comparing the theoretically predicted post-Keplerian expressions T(pK) with the experimental accuracy σ _{T_exp} in measuring the orbital period(s) it is possible to identify those systems whose observations should be re-processed with genuine post-Keplerian models if T^{(pK)}>σ _{T_exp}. It seems just the case for WASP-33 b since σ _{T_exp}=0.04 s, while 3 s≤ T_dra^{(J_2)}≤ 9.5 s, T_dra^{(GR)}=0.36 s.
A Novel Method of Edge Filter Linear Demodulation Using Long Period Grating in Fiber Sensor System
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
A novel method of linear demodulation based on edge filter is presented. An experimental system is built up in which LPG is used as the edge filter. We achieve linear demodulation with a bandwidth of 5nm.
Commissioning and periodic tests of the Esteya® electronic brachytherapy system
Niatsetski, Yury; Ouhib, Zoubir; Ballester, Facundo; Vijande, Javier; Perez-Calatayud, Jose
2015-01-01
A new electronic brachytherapy unit from Elekta, called Esteya®, has recently been introduced to the market. As a part of the standards in radiation oncology, an acceptance testing and commissioning must be performed prior to treatment of the first patient. In addition, a quality assurance program should be implemented. A complete commissioning and periodic testing of the Esteya® device using the American Association of Physicists in Medicine (AAPM), Groupe Européen de Curiethérapie and the European Society for Radiotherapy & Oncology (GEC-ESTRO) guidelines for linacs and brachytherapy units as well as our personal experience is described in this paper. In addition to the methodology, recommendations on equipment required for each test are provided, taking into consideration their availability and traceability of the detectors. Finally, tolerance levels for all the tests are provided, and a specific frequency for each test is suggested. PMID:26034501
Pork meat matured for different periods of time in vacuum-packaging system
Directory of Open Access Journals (Sweden)
Marina Avena Tarsitano
2014-02-01
Full Text Available The objective of this study was to evaluate the quality of pork meat when matured. The treatments evaluated were: meat no maturated; meat matured for 3 days; meat matured for 6 days. The pH, water loss percentage, and liquid lost in thawing displayed a decreasing linear regression while the fluid lost in cooking showed an increasing linear regression. The L*, a*, b* and chroma showed an increasing linear effect while the tone displayed a decreasing linear regression. The mesophilic and psychrotrophic bacteria counts were greater for the treatments that underwent maturation. The shear force decrease linearly with the increase in the maturation period. The MFI, lipid oxidation, and sensory analyses were not affected by treatments. The maturation of the pork meat improved the color, reduced the pH and increased the tenderness. There was no change in the lipid stability of the meat, nor sensory damage.
Directory of Open Access Journals (Sweden)
Santhi Baskaran
2010-12-01
Full Text Available Energy consumption is a critical design issue in real-time systems, especially in battery- operated systems. Maintaining high performance, while extending the battery life between charges is an interesting challenge for system designers. Dynamic Voltage Scaling (DVS allows a processor to dynamically change speed and voltage at run time, thereby saving energy by spreading run cycles into idle time.Knowing when to use full power and when not, requires the cooperation of the operating system scheduler. Usually, higher processor voltage and frequency leads to higher system throughput whileenergy reduction can be obtained using lower voltage and frequency. Instead of lowering processorvoltage and frequency as much as possible, energy efficient real-time scheduling adjusts voltage andfrequency according to some optimization criteria, such as low energy consumption or high throughput,while it meets the timing constraints of the real-time tasks. As the quantity and functional complexity ofbattery powered portable devices continues to raise, energy efficient design of such devices has becomeincreasingly important. Many real-time scheduling algorithms have been developed recently to reduceenergy consumption in the portable devices that use DVS capable processors. Extensive power awarescheduling techniques have been published for energy reduction, but most of them have been focusedsolely on reducing the processor energy consumption. While the processor is one of the major powerhungry units in the system, other peripherals such as network interface card, memory banks, disks alsoconsume significant amount of power. Dynamic Power Down (DPD technique is used to reduce energyconsumption by shutting down the processing unit and peripheral devices, when the system is idle. Threealgorithms namely Red Tasks Only (RTO, Blue When Possible (BWP and Red as Late as Possible (RLPare proposed in the literature to schedule the real-time tasks in Weakly-hard real
Hori, Tomohide; Ogura, Yasuhiro; Onishi, Yasuharu; Kamei, Hideya; Kurata, Nobuhiko; Kainuma, Motoshi; Takahashi, Hideo; Suzuki, Shogo; Ichikawa, Takashi; Mizuno, Shoko; Aoyama, Tadashi; Ishida, Yuki; Hirai, Takahiro; Hayashi, Tomoko; Hasegawa, Kazuko; Takeichi, Hiromu; Ota, Atsunobu; Kodera, Yasuhiro; Sugimoto, Hiroyuki; Iida, Taku; Yagi, Shintaro; Taniguchi, Kentaro; Uemoto, Shinji
2016-09-01
Advanced liver cirrhosis is usually accompanied by portal hypertension. Long-term portal hypertension results in various vascular alterations. The systemic hemodynamic state in patients with cirrhosis is termed a hyperdynamic state. This peculiar hemodynamic state is characterized by an expanded blood volume, high cardiac output, and low total peripheral resistance. Vascular alterations do not disappear even long after liver transplantation (LT), and recipients with cirrhosis exhibit a persistent systemic hyperdynamic state even after LT. Stability of optimal systemic hemodynamics is indispensable for adequate portal venous flow (PVF) and successful LT, and reliable parameters for optimal systemic hemodynamics and adequate PVF are required. Even a subtle disorder in systemic hemodynamics is precisely indicated by the balance between cardiac output and blood volume. The indocyanine green (ICG) kinetics reflect the patient's functional hepatocytes and effective PVF, and PVF is a major determinant of the ICG elimination constant (kICG) in the well-preserved allograft. The kICG value is useful to set the optimal PVF during living-donor LT and to evaluate adequate PVF after LT. Perioperative management has a large influence on the postoperative course and outcome; therefore, key points and unexpected pitfalls for intensive management are herein summarized. Transplant physicians should fully understand the peculiar systemic hemodynamic behavior in LT recipients with cirrhosis and recognize the critical importance of PVF after LT. PMID:27660671
Institute of Scientific and Technical Information of China (English)
QIANG Ji-Ye; FEI Jin-Xi; CAI Gui-Ping; ZHENG Chun-Long
2007-01-01
With the aid of an improved projective approach and a linear variable separation method,new types of variable separation solutions (including solitary wave solutions,periodic wave solutions,and rational function solutions)with arbitrary functions for (2+1)-dimensional Korteweg-de Vries system are derived.Usually,in terms of solitary wave solutions and rational function solutions,one can find some important localized excitations.However,based on the derived periodic wave solution in this paper,we find that some novel and significant localized coherent excitations such as dromions,peakons,stochastic fractal patterns,regular fractal patterns,chaotic line soliton patterns as well as chaotic patterns exist in the KdV system as considering appropriate boundary conditions and/or initial qualifications.
Damazio, D O; The ATLAS collaboration
2013-01-01
The first long period of data taking of the Large Hadron Collider was finished after 2 years of data in February 2013. The increase of the instantaneous luminosity by more than six orders of magnitude documents impressively the extraordinary success of this running period enabling the ATLAS experiment to collect data of very high quality. However, to ensure a constant and reliable monitoring and data quality assessment of the trigger's point of view, a highly flexible and powerful software framework is essential, covering many different aspects. Aside from drastically changing beam conditions as e.g. increasing pile up, the monitoring frame work has to follow up immediately and flexible all developments of the TDAQ system. The TDAQ monitoring system of ATLAS covers very different aspects as rate measurements, trigger configuration and software tests, data quality assessment and handling of events where the trigger decision has failed. Especially the data quality assessment must be made coherent at the online ...
Oliveira Damazio, Denis; The ATLAS collaboration
2013-01-01
The first long period of data taking of the Large Hadron Collider was finished after 3 years of work in February 2013. The increase of the instantaneous luminosity by more than six orders of magnitude documents impressively the extraordinary success of this running period enabling the ATLAS experiment to collect very high quality data. However, to ensure a constant and reliable monitoring and data quality assessment from the trigger's point of view, a highly flexible and powerful software framework is essential, covering many different aspects. Aside from drastically changing beam conditions as e.g. increasing pile up, the monitoring frame work has to follow up immediately and in a flexible manner all developments of the TDAQ system. The TDAQ monitoring system of ATLAS covers very different aspects as rate measurements, trigger configuration and software tests, data quality assessment and handling of events where the trigger decision has failed. Especially the data quality assessment must be made coherent at ...
A novel order reduction method for nonlinear dynamical system under external periodic excitations
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
The concept of approximate inertial manifold (AIM) is extended to develop a kind of nonlinear order reduction technique for non-autonomous nonlinear systems in second-order form in this paper.Using the modal transformation,a large nonlinear dynamical system is split into a ’master’ subsystem,a ’slave’ subsystem,and a ’negligible’ subsystem.Accordingly,a novel order reduction method (Method I) is developed to construct a low order subsystem by neglecting the ’negligible’ subsystem and slaving the ’slave’ subsystem into the ’master’ subsystem using the extended AIM.As a comparison,Method II accounting for the effects of both ’slave’ subsystem and the ’negligible’ subsystem is also applied to obtain the reduced order subsystem.Then,a typical 5-degree-of-freedom nonlinear dynamical system is given to compare the accuracy and efficiency of the traditional Galerkin truncation (ignoring the contributions of the slave and negligible subsystems),Method I and Method II.It is shown that Method I gives a considerable increase in accuracy for little computational cost in comparison with the standard Galerkin method,and produces almost the same accuracy as Method II.Finally,a 3-degree-of-freedom nonlinear dynamical system is analyzed by using the analytic method for showing predominance and convenience of Method I to obtain the analytically reduced order system.
Baimei Yang; Chunyan Gao; Na Liu; Liang Xu
2015-01-01
We consider a dynamic inventory control and pricing optimization problem in a periodic-review inventory system with price adjustment cost. Each order occurs with a fixed ordering cost; the ordering quantity is capacitated. We consider a sequential decision problem, where the firm first chooses the ordering quantity and then the sale price to maximize the expected total discounted profit over the sale horizon. We show that the optimal inventory control is partially charac...
Multitudes of Stable States in a Periodically Driven Electron-Nuclear Spin System in a Quantum Dot
Korenev, V. L.
2010-01-01
The periodical modulation of circularly polarized light with a frequency close to the electron spin resonance frequency induces a sharp change of the single electron spin orientation. Hyperfine interaction provides a feedback, thus fixing the precession frequency of the electron spin in the external and the Overhauser field near the modulation frequency. The nuclear polarization is bidirectional and the electron-nuclear spin system (ENSS) possesses a few stable states. A similar frequency-loc...
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
In this paper, we present an object reduction for nonlinear partial differential equations. As a concrete example of its applications in physical problems, this method is applied to the (2+1)-dimensional Boiti-Leon-Pempinelli system, which has the extensive physics background, and an abundance of exact solutions is derived from some reduction equations. Based on the derived solutions, the localized structures under the periodic wave background are obtained.
Institute of Scientific and Technical Information of China (English)
ZHENG Chun-Long
2004-01-01
By means of the standard truncated Painleve expansion and a variable separation approach, a general variable separation solution of the generalized Burgers system is derived. In addition to the usual localized coherent soliton excitations like dromions, lumps, rings, breathers, instantons, oscillating soliton excitations, peakons, foldons,and previously revealed chaotic and fractal localized solutions, some new types of excitations - compacton and Jacobi periodic wave solutions are obtained by introducing appropriate lower dimensional piecewise smooth functions and Jacobi elliptic functions.
Fuel Cell/Battery Powered Bus System. Final Report for period August 1987 - December 31, 1997
Energy Technology Data Exchange (ETDEWEB)
Wimmer, R.
1999-01-01
Today, fuel cell systems are getting much attention from the automotive industry as a future replacement for the internal combustion engine (ICE). Every US automobile manufacturer and most foreign firms have major programs underway to develop fuel cell engines for transportation. The objective of this program was to investigate the feasibility of using fuel cells as an alternative to the ICE. Three such vehicles (30-foot buses) were introduced beginning in 1994. Extensive development and operational testing of fuel cell systems as a vehicle power source has been accomplished under this program. The development activity investigated total systems configuration and effectiveness for vehicle operations. Operational testing included vehicle performance testing, road operations, and extensive dynamometer emissions testing.
Bott Periodicity for Z_2 Symmetric Ground States of Gapped Free-Fermion Systems
Kennedy, R.; Zirnbauer, M. R.
2016-03-01
Building on the symmetry classification of disordered fermions, we give a proof of the proposal by Kitaev, and others, for a "Bott clock" topological classification of free-fermion ground states of gapped systems with symmetries. Our approach differs from previous ones in that (i) we work in the standard framework of Hermitian quantum mechanics over the complex numbers, (ii) we directly formulate a mathematical model for ground states rather than spectrally flattened Hamiltonians, and (iii) we use homotopy-theoretic tools rather than K-theory. Key to our proof is a natural transformation that squares to the standard Bott map and relates the ground state of a d-dimensional system in symmetry class s to the ground state of a ( d + 1)-dimensional system in symmetry class s + 1. This relation gives a new vantage point on topological insulators and superconductors.
Bott periodicity for Z2 symmetric ground states of gapped free-fermion systems
Kennedy, Ricardo
2014-01-01
Building on the symmetry classification of disordered fermions, we give a proof of the proposal by Kitaev, and others, for a "Bott clock" topological classification of free-fermion ground states of gapped systems with symmetries. Our approach differs from previous ones in that (i) we work in the standard framework of Hermitian quantum mechanics over the complex numbers, (ii) we directly formulate a mathematical model for ground states rather than spectrally flattened Hamiltonians, and (iii) we use homotopy-theoretic tools rather than K-theory. Key to our proof is a natural transformation that squares to the standard Bott map and relates the ground state of a d-dimensional system in symmetry class s to the ground state of a (d+1)-dimensional system in symmetry class s+1. This relation gives a new vantage point on topological insulators and superconductors.
Avsyuk, Yu N; 10.1007/s11038-011-9381-8; 10.1007/s11038-011-9381-8
2012-01-01
We have studied long period, 206 and 412 day, variations in tidal sea level corresponding to various moon phases collected from five observatories in the Northern and Southern hemispheres. Variations in sea level in the Bay of Fundy, on the eastern Canadian seaboard, with periods of variation 206 days, and 412 days, have been discovered and carefully studied by C. Desplanque and D. J. Mossman (2001, 2004). The current manuscript focuses on analyzing a larger volume of observational sea level tide data as well as on rigorous mathematical analysis of tidal force variations in the Sun-Earth-Moon system. We have developed a twofold model, both conceptual and mathematical, of astronomical cycles in the Sun-Earth-Moon system to explain the observed periodicity. Based on an analytical solution of the tidal force variation in the Sun-Earth-Moon system, it is shown that the tidal force can be decomposed into two components: the Keplerian component and the Perturbed component. The Perturbed component of the tidal force...
Multi-Period Optimization for Voltage Control System in Transmission Grids
DEFF Research Database (Denmark)
Qin, Nan; Chen, Si; Liu, Chengxi;
2015-01-01
Automatic Voltage Control (AVC) systems maintain the voltage in an acceptable range and minimize the power loss of the grid by coordinately regulating the controllable components. Switchable shunts and tap-able transformers are expected to be operated as few times as possible. This paper proposes...
Systems and methods for controlling energy use during a demand limiting period
Wenzel, Michael J.; Drees, Kirk H.
2016-04-26
Systems and methods for limiting power consumption by a heating, ventilation, and air conditioning (HVAC) subsystem of a building are shown and described. A feedback controller is used to generate a manipulated variable based on an energy use setpoint and a measured energy use. The manipulated variable may be used for adjusting the operation of an HVAC device.
Pricing and Inventory Control Strategy for a Periodic-Review Energy Buy-Back System
Institute of Scientific and Technical Information of China (English)
ZHANG Jihong; CHEN Hongqiao; DING Xiaosong; LI Xian
2016-01-01
Along with the rapid development of economics and enhancement of industrialization,the power demand keeps rising and frequently creates mismatch between demand and supply in electricity.This provides miscellaneous energy buy-back programs with great opportunities.Such programs,when activated,offer certain amount of financial compensations to participants for reducing their energy consumption during peak time.They aim at encouraging participants to shift their electricity usage from peak to non-peak time,and thereby release the demand pressure during peak time.This paper considers a periodic-review joint pricing and inventory decision model under an energy buy-back program over finite planning horizons,in which the compensation levels,setup cost and additive random demand function are incorporated.The objective is to maximize a manufacturer's expected total profit.By using Veinott's conditions,it is shown that the manufacturer's optimal decision is a state dependent (s,S,P) policy under a peak market condition,or partly an (s,S,A,P) policy under the normal market condition.
The Earth-Moon system during the Late Heavy Bombardment period
Jorgensen, Uffe Graae; Hatsukawa, Yuichi; Frei, Robert; Oshima, Masumi; Toh, Yosuke; Kimura, Atsushi
2009-01-01
The Late Heavy Bombardment (LHB) period is the narrow time interval between 3.8 and 3.9 Gyr ago, where the bulk of the craters we see on the Moon formed. Even more craters formed on the Earth. During a field expedition to the 3.8 Gyr old Isua greenstone belt in Greenland, we sampled three types of metasedimentary rocks, that contain direct traces of the LHB impactors by a seven times enrichment (150 ppt) in iridium compared to present day ocean crust (20 ppt). We show that this enrichment is in agreement with the lunar cratering rate, providing the impactors were comets, but not if they were asteroids. Our study is a first direct indication of the nature of the LHB impactors, and the first to find an agreement between the LHB lunar cratering rate and the Earth's early geochemical record (and the corresponding lunar record). The LHB comets that delivered the iridium we see at Isua will at the same time have delivered the equivalent of a km deep ocean, and we explain why one should expect a cometary ocean to be...
Koziorowska-Gilun, M; Szurnicka, M; Dziekonska, A; Kordan, W; Giżejewski, Z; Filipowicz, K
2016-04-01
The objective of this study was to make the preliminary characterization of the antioxidant defence systems of the yellow fraction (YF) of red deer's (Cervus elaphus L.) semen during the rutting period. The semen was collected using artificial vagina (AV). The studies included spectrophotometric determination of antioxidant enzymes activities such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). We also analysed the contents of low-molecular antioxidants such as L-glutathione (GSH + GSSG), L-ascorbate (ASC) and total antioxidant status (TAS). Additionally, the samples were subjected to PAGE and stained for SOD and GPx activities. It was demonstrated that the yellow fraction exhibited activities of SOD and GPx, with the highest activities in September and October. CAT activity was not detected. Staining for the SOD and GPx activities confirmed three protein bands with SOD activity and one protein band with GPx activity. The content of GSH + GSSG was similar in trials dating from October to December contrary to the content of ASC which was high in samples from September and October. The stable rate of TAS was observed during the whole rutting period. The results of this study showed that the YF of red deer semen is equipped with basic battery of antioxidant enzymes comprising SOD and GPx, with the supporting role of GSH + GSSG and ASC. Moreover, the samples obtained at the peak of the rutting period occurring from September to October had the highest enzymatic activity in comparison with remaining months of the rutting period, which contributed to the high quality of the semen by preventing it from the formation of oxidative stress during the short period of intense sexual activity of male red deer. The better understanding of the mechanisms of antioxidant defence systems in the YF of deer's semen may contribute to the potential use of this fraction in technology of wild ruminant semen preservation. PMID:26854018
Dolan, Elizabeth A.; Venable, Richard M.; Pastor, Richard W.; Brooks, Bernard R.
2002-01-01
We demonstrate the ease and utility of simulating heterogeneous interfacial systems with P2(1) and Pc periodic boundary conditions which allow, for example, lipids in a membrane to switch leaflets. In preliminary tests, P2(1) was shown to yield equivalent results to P1 in simulations of bulk water, a water/vacuum interface, and pure DPPC bilayers with an equal number of lipids per leaflet; equivalence of Pc and P1 was also demonstrated for the former two systems. P2(1) was further tested in s...
Indian Academy of Sciences (India)
VENKATESH P R; VENKATESAN A
2016-07-01
Additional sinusoidal and different non-sinusoidal periodic perturbations applied to the periodically forced nonlinear oscillators decide the maintainance or inhibitance of chaos. It is observed that the weak amplitude of the sinusoidal force without phase is sufficient to inhibit chaos rather than the other non-sinusoidal forces and sinusoidal force with phase. Apart from sinusoidal force without phase, i.e., from various non-sinusoidal forces and sinusoidal force with phase, square force seems to be an effective weak perturbation to suppress chaos. The effectiveness of weak perturbation for suppressing chaos is understood with the total power average of the external forces applied to the system. In any chaotic system, the total power average of the external forces isconstant and is different for different nonlinear systems. This total power average decides the nature of the force to suppress chaos in the sense of weak perturbation. This has been a universal phenomenon for all the chaoticnon-autonomous systems. The results are confirmed by Melnikov method and numerical analysis. With the help of the total power average technique, one can say whether the chaos in that nonlinear system is to be supppressed or not.
Effect of periodic backwash in the submerged membrane adsorption hybrid system
Khirani, Sarah; SMITH, Paul James; Manero, Marie-Hélène; Ben Aim, Roger; Vigneswaran, Saravanamuth
2006-01-01
The submerged membrane adsorption hybrid system (SMAHS) is an attractive solution in treating wastewater; however it faces membrane fouling although to a less extent. In this study, different adsorbents and resins were investigated in order to find a substitute to the powdered activated carbon (PAC); The effect of new backflush was also studied in further reducing the membrane fouling. The SMAHS led to 72–86% dissolved organic carbon (DOC) removal. A detailed study on the transmembrane pressu...
Veysset, P; Lherm, M; Roulenc, M; Troquier, C; Bébin, D
2015-12-01
Over the past 23 years (1990 to 2012), French beef cattle farms have expanded in size and increased labour productivity by over 60%, chiefly, though not exclusively, through capital intensification (labour-capital substitution) and simplifying herd feeding practices (more concentrates used). The technical efficiency of beef sector production systems, as measured by the ratio of the volume value (in constant euros) of farm output excluding aids to volume of intermediate consumption, has fallen by nearly 20% while income per worker has held stable thanks to subsidies and the labour productivity gains made. This aggregate technical efficiency of beef cattle systems is positively correlated to feed self-sufficiency, which is in turn negatively correlated to farm and herd size. While volume of farm output per hectare of agricultural area has not changed, forage feed self-sufficiency decreased by 6 percentage points. The continual increase in farm size and labour productivity has come at a cost of lower production-system efficiency - a loss of technical efficiency that 20 years of genetic, technical, technological and knowledge-driven progress has barely managed to offset. PMID:26577645
International Nuclear Information System (INIS)
The conceptual design of an on-line, near-real-time nondestructive assay instrumentation network for the Los Alamos Plutonium Facility is complete. Analysis of instrument history data indicates that the instrument certification procedures need improvement. Analysis of exhaust filter data has led to the derivation of a buildup prediction equation that is a function of throughput. This suggests that development of a generalized model is possible. A number of routine reports are now available from the Plutonium Facility/Los Alamos Safeguards System including inventories and active reports
An Integrated Inventory-Transportation System with Periodic Pick-Ups and Leveled Replenishment
Directory of Open Access Journals (Sweden)
Thomas Volling
2013-11-01
Full Text Available In this paper we develop a combined inventory-transportation system. The general idea is to integrate a simple replenishment policy with a routing component to derive operationally consistent standard routes as a basis for milk run design. The most interesting feature of the approach is that we combine stochastic vehicle routing with a replenishment policy which makes use of inventory to level the variability propagated into transportation operations. To evaluate the approach, we compare its performance with stochastic vehicle routing as well as sequential vehicle routing and replenishment planning. With respect to these approaches, substantial gains are achieved.
Energy Technology Data Exchange (ETDEWEB)
Shirk, D.G.; Bearse, R.C.; Marshall, R.S.; Baker, A.L.; Thomas, C.C. Jr.
1982-02-01
The conceptual design of an on-line, near-real-time nondestructive assay instrumentation network for the Los Alamos Plutonium Facility is complete. Analysis of instrument history data indicates that the instrument certification procedures need improvement. Analysis of exhaust filter data has led to the derivation of a buildup prediction equation that is a function of throughput. This suggests that development of a generalized model is possible. A number of routine reports are now available from the Plutonium Facility/Los Alamos Safeguards System including inventories and active reports.
Costa-Castelló, R.; Olm, J. M.; Ramos, G. A.
2011-07-01
This article analyses stability and performance features of different design schemes for digital repetitive control systems subject to references/disturbances that exhibit non-uniform frequency. Aiming at maintaining a constant value for the ratio T p /T s , T p being the period of the reference/disturbance signal and T s being the sampling period, two approaches are proposed. The first one deals with the real-time adaptation of T s to the actual changes of T p ; stability is studied by means of an LMI gridding method and also using robust control techniques. The second one propounds the introduction of an additional compensator that annihilates the effect of the time-varying sampling in the closed-loop system and forces its behaviour to coincide with that of an a priori selected nominal sampling period; the internal stability of the compensator-plant subsystem is checked by means of LMI gridding. The theoretical results are experimentally tested and compared through a mechatronic plant model.
Thermodynamics of two-stroke engine based on periodically driven two-level system
Chvosta, Petr; Holubec, Viktor; Ryabov, Artem; Einax, Mario; Maass, Philipp
2010-01-01
We investigate a microscopic motor based on an externally driven two-level system. One cycle of the motor operation consists of two strokes. Within each stroke, the two energy levels are driven with a constant rate. The occupation probabilities of the two states evolve according to the Pauli rate equation and represent the delayed system's response to the external driving. We give the exact solution of the Pauli rate equation and discuss its thermodynamical consequences. In particular, we calculate the motor's efficiency, the power output, and the performance dependence on the control parameters. Secondly, we introduce an augmented stochastic process which reflects, at a given time, both the occupation probabilities for the two states and the time spent in the individual states during the previous evolution. Our exact calculation of the evolution operator for the augmented process allows one to discuss in detail the probability density for the work during the limit cycle. In the strongly irreversible regime, the density shows strong deviations from a Gaussian shape.
International Nuclear Information System (INIS)
Interfacial behavior of extractant molecules and their interaction with metal ions has been investigated. Consideration was also given to the question of microscopic interfaces, i.e., those associated with reversed micelles as well as microemulsions. NMR spectroscopy, fluorescence spectroscopy, quasi-elastic light scattering, vapor pressure osmometry, and Karl-Fischer titrimetry provided support for findings obtained from interfacial tension experiments that reversed micelles are formed, under certain conditions, in the system di(2-ethylhexyl)phosphoric acid (HDEHP)/ n-hexane/CaCl2 solution. These techniques were further extended to include different organophosphorus acids (PC 88A and CYANEX 272), diluent (benzene), and metal ions (Co2+, Ni2+, and Zn2+) to determine whether reversed micellization occurs in solvent extraction systems which employ organophosphorus acids. A preliminary general model of the aggregation mechanism for metal-extractant complexes has been proposed. Also various laser techniques have been used to investigate the structure and dynamics of extractant films. A laser fluorescence apparatus for probing interfacial dynamics is under construction. 64 refs., 29 figs
Directory of Open Access Journals (Sweden)
Cláudia Simone Madruga Lima
2010-12-01
Full Text Available A physalis (Physalis peruviana é uma pequena fruta com grandes potencialidades, que, associadas ao seu ciclo curto e às propriedades nutracêuticas, apresenta possibilidade de alto retorno econômico. O objetivo deste trabalho foi avaliar o sistema de tutoramento e a época de transplante mais adequados para o crescimento e a produção de frutos de P. peruviana nas condições edafoclimáticas do sul do Rio Grande do Sul. O trabalho foi desenvolvido em Pelotas, RS, na safra de 2007/2008. O transplante de mudas de physalis foi realizado em duas épocas (época 1, 21/11/2007 e época 2 15/01/2008, sendo as plantas tutoradas em quatro sistemas de condução (sistema "V" invertido, sistema triangular, sistema vertical com bambu e sistema vertical com fitilho, semelhantes aos utilizados na cultura do tomateiro. O delineamento experimental adotado foi de blocos casualizados, com três repetições, sendo cada um representado por dez plantas. Os tratamentos formaram um fatorial 2x4 (épocas de transplante x sistemas de tutoramento. As variáveis analisadas foram: incremento do comprimento e da área da seção do ramo principal, área da seção do ramo principal, produtividade e eficiência produtiva. Foi evidenciado que a primeira época de transplante associada aos sistemas de tutoramento "V" invertido e triangular proporciona melhor desempenho agronômico das plantas de physalis.The cape-gooseberry (Physalis peruviana is a small fruit with great potentialities that whether associated to its short cycle and nutraceutical properties it shows high economical return. The work aimed to evaluate the best training system and replant period to plant growth, production and fruit quality of P. peruviana under edaphoclimatic at conditions of southern Rio Grande do Sul. The trial was carried out in Pelotas, RS, in 2007/2008 crop. Transplanting seedlings cape-gooseberry was conducted in two seasons Plant replanting was done in two periods (period 1, 21
Artz, Thomas; Tesmer Née Böckmann, Sarah; Nothnagel, Axel
2011-09-01
We present an empirical model for periodic variations of diurnal and sub-diurnal Earth rotation parameters (ERPs) that was derived based on the transformation of normal equation (NEQ) systems of Very Long Baseline Interferometry (VLBI) observing sessions. NEQ systems that contain highly resolved polar motion and UT1-TAI with a temporal resolution of 15 min were generated and then transformed to the coefficients of the tidal ERP model to be solved for. To investigate the quality of this model, comparisons with empirical models from the Global Positioning System (GPS), another VLBI model and the model adopted by the conventions of the International Earth Rotation and Reference Systems Service (IERS) were performed. The absolute coefficients of these models agree almost completely within 7.5 μ as in polar motion and 0.5 μ s in UT1-TAI. Several bigger differences exist, which are discussed in this paper. To be able to compare the model estimates with results of the continuous VLBI campaigns, where signals with periods of 8 and 6 h were detected, terms in the ter- and quarter-diurnal band were included in the tidal ERP model. Unfortunately, almost no common features with the results of continuous VLBI campaigns or ERP predictions in these tidal bands can be seen.
Energy Technology Data Exchange (ETDEWEB)
Hey, Heyder
1996-12-31
We have study three quantum systems under time dependent external fields. The first one is an harmonic oscillator and the external field is quasiperiodic. We prove that the autocorrelation spectrum is absolutely transient continuous covering the real line on the resonant case or pure point under supplementary diophantine conditions. The second one refers to the spin tunneling. We show that an external periodic field may causes a blocking of spin tunneling. The last problem concerns to the resonances of the Floquet spectrum on the non-perturbative region of parameters for the model of an atom with one bound state under an external periodic field. The problems of Quantum Chaology and Quantum Stability are the predominant points of view in this work. (author) 59 refs., 15 figs., 6 tabs.
International Nuclear Information System (INIS)
The creation of the rapid and sensitive system for the determination of the Alpha-radioactivity in the Environmental samples has been determined as the main goal of the Research Contract No. 7200RO/RB. As a result of the first stage of the research accomplished in the year 1993, the prototype of the system based on the combination of the laser photoionization mass spectrometry and many-channel alpha-spectrometer has been built and tested. To improve the sensitivity it was proposed to add one more stage to the laser photoionization mass-spectrometer. To develop the high position sensitivity of the system it was proposed to include into the alpha-radiometer SI strip-detector with submicron position sensitivity. Hardware and software for the laser-semiconductor monitoring system of alpha-radionuclides in the environment have been further developed and tested in frames of the IAEA Research Contract No. 7200/R1/RB. Optimization of the sample evaporation with one more stage of photoionization has been successfully performed in the laser photoionization mass-spectrometer. The automatization of the measurement procedure is under way by means of the IBM PC-386 and specially designed electronic units. The evaluated sensitivity of the new set-up is in the range of 1.0 Bq/kg. A bulk measurement of the alpha-radioactivity concentration in soil samples from the Chernobyl region (100 km) have been performed by means of thick samples method and built under this contract alpha-radiometer with large area SI semiconductor detectors. The lowest detectable level was in the range 100 Bq/kg without any radiochemical separation. Comparison with the data obtained for the same probes by means of the thin sample (with radiochemical separation) has shown higher Pu-concentration values obtained by means of the thick samples. For the first time the Sl-strip-detector with 128 channels has been applied for the alpha-radiometry purposes. Different read-out electronics (including the most
A Practical Approach to Improve Optical Channel Utilization Period for Hybrid FSO/RF Systems
Directory of Open Access Journals (Sweden)
Ahmet Akbulut
2014-01-01
Full Text Available In hybrid FSO/RF systems, mostly a hard switching mechanism is preferred in case of the FSO signal level falls below to the predefined threshold. In this work, a computationally simple approach is proposed to increase the utilization of the FSO channels bandwidth advantage. For the channel, clear air conditions have been supposed with the atmospheric turbulence. In this approach, FSO bit rate is adaptively changed to achieve desired BER performance. An IM/DD modulation, OOK (NRZ format has been used to show the benefit of the proposed method. Furthermore, to be more realistic with respect to the atmospheric turbulence variations within a day, some experimental observations have been followed up.
Mitral restenosis in the early postoperative period of a patient with systemic lupus erythematosus
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Pomerantzeff Pablo Maria Alberto
1999-01-01
Full Text Available A forty eight year old woman, who had undergone mitral comissurotomy and subsequently developed early restenosis, presented with major comissural fusion and verrucous lesions on the cuspid edges of the mitral valve, with normal subvalvar apparatus. Patient did well for the first six months after surgery when she began to present dyspnea on light exertion. A clinical diagnosis of restenosis was made, which was confirmed by an echocardiogram and cardiac catheterization. She underwent surgery, and a stenotic mitral valve with verrucous lesions suggesting Libman-Sacks' endocarditis was found. Because the diagnosis of systemic lupus erythematosus (SLE had not been confirmed at that time, a bovine pericardium bioprosthesis (FISICS-INCOR was implanted. The patient did well in the late follow-up and is now in NYHA Class I .
Herath, Anura
1993-01-01
Increasing the productivity of coconut-based farming systems is an important development issue. To achieve increased productivity, intercropping of coffee, pepper and cocoa with coconut was recommended. Farmers’ adoption of such intercropping on a sustained basis has been very poor. The paper provides some intercropping plans developed using a multi-period linear programming model of the coconut-based farming systems. Farmers’ objectives, namely profit maximizing and survival, and resource co...
A condition-based maintenance policy with non-periodic inspections for a two-unit series system
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Castanier, B. [IRCCyN/Ecole des Mines de Nantes, Departement Automatique et Productique, 4 rue Alfred Kastler, F-44307 Nantes (France)]. E-mail: bruno.castanier@emn.fr; Grall, A. [Universite de Technologie de Troyes, ISTIT-CNRS FRE 2732, Equipe Modelisation et Surete des Systemes, 12, rue Marie Curie, BP 2060-10010 Troyes Cedex (France)]. E-mail: antoine.grall@utt.fr; Berenguer, C. [Universite de Technologie de Troyes, ISTIT-CNRS FRE 2732, Equipe Modelisation et Surete des Systemes, 12, rue Marie Curie, BP 2060-10010 Troyes Cedex (France)]. E-mail: christophe.berenguer@utt.fr
2005-01-01
This paper considers a condition-based maintenance policy for a two-unit deteriorating system. Each unit is subject to gradual deterioration and is monitored by sequential non-periodic inspections. It can be maintained by good as new preventive or corrective replacements. Every inspection or replacement entails a set-up cost and a component-specific unit cost but if actions on the two components are combined, the set-up cost is charged only once. A parametric maintenance decision framework is proposed to coordinate inspection/replacement of the two components and minimize the long-run maintenance cost of the system. A stochastic model is developed on the basis of the semi-regenerative properties of the maintained system state and the associated cost model is used to assess and optimize the performance of the maintenance model. Numerical experiments emphasize the interest of a control of the operation groupings.
Energy Technology Data Exchange (ETDEWEB)
Huynh, K.T., E-mail: tuan.huynh@utt.f [Universite de technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279-12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Barros, A., E-mail: anne.barros@utt.f [Universite de technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279-12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Berenguer, C., E-mail: christophe.berenguer@utt.f [Universite de technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279-12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Castro, I.T., E-mail: inmatorres@unex.e [Departamento de Matematicas, Escuela Politecnica, 10071 Caceres (Spain)
2011-04-15
This paper deals with the condition-based maintenance of single-unit systems which are subject to the competing and dependent failures due deterioration and traumatic shock events. The main aim is to provide a model to assess the value of condition monitoring information for the maintenance decision-making. A condition-based periodic inspection/replacement policy is developed and compared with a benchmark time-based block replacement policy. Numerical results show that it is indeed useful to follow closely the actual evolution of the system to adapt the maintenance decisions to the true system state to improve the performance of maintenance policies. The analysis of the maintenance costs savings can be used to justify or not the choice to implement a policy based on condition monitoring information and to invest in condition monitoring devices.
Finite Elements for a Beam System With Nonlinear Contact Under Periodic Excitation
Hazim, Hamad
2009-01-01
Solar arrays are structures which are connected to satellites; during launch, they are in a folded position and submitted to high vibrations. In order to save mass, the flexibility of the panels is not negligible and they may strike each other; this may damage the structure. To prevent this, rubber snubbers are mounted at well chosen points of the structure; a prestress is applied to the snubber; but it is quite difficult to check the amount of prestress and the snubber may act only on one side; they will be modeled as one sided springs (see figure 2). In this article, some analysis for responses (displacements) in both time and frequency domains for a clamped-clamped Euler-Bernoulli beam model with a spring are presented. This spring can be unilateral or bilateral fixed at a point. The mounting (beam +spring) is fixed on a rigid support which has a sinusoidal motion of constant frequency. The system is also studied in the frequency domain by sweeping frequencies between two fixed values, in order to save the...
Element separation before matter accretion of solar system planets in the light of the periodic law
International Nuclear Information System (INIS)
The proofs of element separation in protoplanet nebula of Protosolar system have been found. For this purpose the K1/K2 ratios of concentration of elements - chemical analogs in the rock samples of Venus, Earth, Mars and meteorites were compared. The new approach enabled the comparison of K1/K2 of the Earth and meteorites with K1/K2 of Venus and Mars obtained by elemental analysis of their rock samples. It has been found that at J2/J1>1 chemical analogs have K1/K2: on Venus probably less or at least commeasurable, on Mars and, especially in meteorites, considerably (several orders of magnitude) greater than in the Earth rocks (J1 and J2 are charged atoms fractions in photon flux of the Protosun). Other facts, which agree with the relationship K1/K2=f(R), where R is the average distance of a body from the Sun, were found. 41 refs.; 1 fig.; 5 tabs
Stability Of The Regional Banking Systems In The Crisis And Post-Crisis Periods
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Yelena Pavlovna Gurova
2014-12-01
Full Text Available In connection with the recent crises has become more urgent topic of estimating the probability of bankruptcy of financial institutions. However, do not analyze the level of bankruptcies in the «regional banking systems» and its dependence on certain bank characteristics, the economic situation in the region. The subject of this study is to estimate the probability of medium-sized («non-capital» regional banks bankruptcy. Purpose of the article is to identify the main factors that have the greatest impact on the probability of default of the situation of regional banks. The study used an analytical and theoretical method is conducted econometric analysis. For performance revealed a significant difference in the factors influencing the onset of medium-sized regional situation of default («non-capital» banks, compared with larger banks. First to assess the likelihood of bankruptcy is used the concentration index of banks included in the model and significant macro variables. Results are applicable, from our point of view, the evaluation and more precise definition of the probability of default CBR regional banks.
The Effects of Quercetin and Retinoic acid on Skeletal System of Rat Embryos in Prenatal Period
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Nahid Gohari-Behbahani
2014-12-01
Full Text Available Background: Prenatal rat embryo exposure to retinoid induces some malformations in various organs, the most active and teratogenic metablolite is all-trans-retinoic acid (atRA. The teratogenic effects of some drugs can be prevented by the application of antioxidant drugs and stimulation of the maternal immune system. Also, quercetin, a naturally occurring flavonoid has excellent antioxidant properties. Therefore, in this study, the prophylactic effect of quercetin on teratogenic effects of atRA was evaluated. Materials and Methods: In this experimental study, 40 pregnant rats were divided into 7 groups. Control group received normal saline and test groups received dimethylsulfoxide (DMSO, quercetin (75 mg/kg, quercetin (200 mg/kg, atRA (25 mg/kg, atRA (25 mg/kg plus quercetin (75 mg/kg and atRA (25 mg/kg plus quercetin (200 mg/kg, intraperitoneally at 8-10th days of gestation. Fetuses were collected at 20th day of gestation and after determination of weight and length; they were stained by Alizarin red-Alcian blue method. Results: Cleft palate, exencephaly and spina bifida incidence were 30.76%, 61.53% and 30.76% range in group which received only atRA. Cleft palate, exencephaly and spina bifida incidence were 11.11%, 16.66% and 5.55% in group which received atRA plus quercetin (75 mg/kg. However, cleft palate, exencephaly and spina bifida incidence were 10.52%, 10.52% and 0% in group which received atRA plus quercetin (200 mg/kg. The means of weight and length of fetuses from rat that received atRA plus quercetin (75 mg/kg were significantly greater than those received only atRA. Conclusion: It is concluded that quercetin decreased teratogenicity induced by atRA, but this subject needs more detailed evaluation.
Raupach, Marc
2015-01-01
The development and first applications of a new periodic energy decomposition analysis (pEDA) scheme for extended systems based on the Kohn-Sham approach to density functional theory are described. The pEDA decomposes the binding energy between two fragments (e.g. the adsorption energy of a molecule on a surface) into several well-defined terms: preparation, electrostatic and dispersion interaction, Pauli repulsion and orbital relaxation energies. The pEDA presented here for an AO-based implementation can handle restricted and unrestricted fragments for 0D to 3D systems considering periodic boundary conditions with and without the determination of fragment occupations. For the latter case, reciprocal space sampling is enabled. The new method gives comparable results to established schemes for molecular systems and shows good convergence with respect to the basis set (TZ2P), the integration accuracy and k-space sampling. Four typical bonding scenarios for surface adsorbate complexes were chosen to highlight th...
Knutson, Heather A; Montet, Benjamin T; Kao, Melodie; Ngo, Henry; Howard, Andrew W; Crepp, Justin R; Hinkley, Sasha; Bakos, Gaspar A; Batygin, Konstantin; Johnson, John Asher; Morton, Timothy D; Muirhead, Philip S
2013-01-01
In this paper we search for distant massive companions to known transiting hot Jupiters that may have influenced the dynamical evolution of these systems. We present new radial velocity observations for a sample of 51 hot Jupiters obtained using the Keck HIRES instrument, and use these observations to search for long-term radial velocity accelerations. We find new, statistically significant accelerations in seven systems, including: HAT-P-10, HAT-P-20, HAT-P-22, HAT-P-29, HAT-P-32, WASP-10, and XO-2. We combine our radial velocity fits with Keck NIRC2 AO imaging data to place constraints on the allowed masses and orbital periods of the companions. The estimated masses of the companions range between 1-500 M_Jup, with orbital semi-major axes typically between 1-75 AU. A significant majority of the companions detected by our survey are constrained to have minimum masses comparable to or larger than those of the short-period hot Jupiters in these systems, making them candidates for influencing the orbital evolut...
Directory of Open Access Journals (Sweden)
G. STEFAN
2013-12-01
Full Text Available The techniques of carp culture are highly diversified, ranging from the extensive production in pond or open water with no fertilization or supplemental feeding to highly intensive systems in concrete tanks or cages. Among the different carp species, common carp is the best species reared in intensive monoculture, the others (Chinese and Indian carps being usually cultivated in polyculture (P. Kestemont, 1995. An experiment was conducted in inside recirculation system conditions to identify the technological performances on carp growth and survival at the Fishing and Aquaculture Department, Galati, during winter period (February, 2007 – March, 2007. The 1-year-old carp (Cyprinus carpio 4792g; 4594 g; 4561 g and 4525 g (total weight grew to 7384g; 7017g; 6924g and 7125 g in 44 days in aquarium 1, 2, 3 and 4, respectively. In all aquariums, the fish appeared healthy and no mortality was observed. Feed conversion efficiencies (FCE had similar values among all aquariums, the highest FCE being found in B4 aquarium with 1, 57 value. Water quality parameters were acceptable range for fish culture. Results show that the carp rearing during winter period in the inside recirculation system is a very good economic solution.
Directory of Open Access Journals (Sweden)
Ronaldo Vieira Cruz
2010-01-01
Full Text Available This article focuses on the problem of parameter estimation of the uncoupled, linear, short-period aerodynamic derivatives of a “Twin Squirrel” helicopter in level flight and constant speed. A flight test campaign is described with respect to maneuver specification, flight test instrumentation, and experimental data collection used to estimate the aerodynamic derivatives. The identification problem is solved in the time domain using the output-error approach, with a combination of Genetic Algorithm (GA and Levenberg-Marquardt optimization algorithms. The advantages of this hybrid GA and gradient-search methodology in helicopter system identification are discussed.
Energy Technology Data Exchange (ETDEWEB)
Wang Fengyan [College of Science, Jimei University, Xiamen Fujian 361021 (China)]. E-mail: wangfy68@163.com; Zeng Guangzhao [Department of Mathematics, ShaoGuan University, ShaoGuan, GuangDong 512005 (China)]. E-mail: guangzhaoz@sgu.edu.cn
2007-05-15
In this paper, we introduce and study a Lotka-Volterra predator-prey system with impulsive ratio-harvesting the prey and time delays. By using Floquet theory and small amplitude perturbation skills, we discuss the boundary periodic solutions for predator-prey system under periodic pulsed conditions. The stability analysis of the boundary periodic solution yields an invasion threshold of the predator. Further, by use of the coincidence degree theorem and its related continuous theorem we prove the existence of the positive periodic solutions of the system when the value of the coefficient is large than the threshold. Finally, by comparing bifurcation diagrams with different bifurcation parameters, we show that the impulsive effect and the time delays bring to the system to be more complex, which experiences a complex process of cycles {sup {yields}} quasi-periodic oscillation {sup {yields}} periodic doubling cascade {sup {yields}} chaos.
Institute of Scientific and Technical Information of China (English)
PIAO; Daxiong
2001-01-01
., Wampler, E. J., Gaskell, C. M., Emission-line properties of optically and radio-selected complete quasars samples, Astrophys. J., 1989, 338: 630.［13］Yong, P., Sargent, W. L. W. A., High-resolution study of the absorption spectra of three QSOs: evidence for cosmological evolution in the lyman-alpha lines, Astrophys. J., 1982, 252: 10.［14］Lawrence, J., Zucker, J. R., Readhead, A. C. S. et al., Optical spectra of a complete sample of radio sources I. The spectra, Astrophys. J. Suppl., 1996, 107: 541.［15］Junkkarinen, V. T. , Burbidge E. M. , Smith, H. E. , Spectrophyotometry of six broad absoption line QSOs, Astrophys. J. ,1987, 317, 460.［16］Laor, A., Babcall, J. N., Jannuzi, B. T. et al., The ultraviolet emission properties of 13 quasars, Astrophys. J. Suppl.,1995, 99: 1.［17］Baldwin, J. A., Rees, M. J., Longair, M. S. et al., QSOs with narrow emission lines, Astrophys. J., 1988, 327: 103.［18］Shaver, P. A. , Boksenberg A. , Robertson, J. G. , Spectroscopy of the QSO pair Q0028 + 003/Q0029 + 003, Astrophys.J., 1982, 261: L7.［19］Baldwin, J. A., Netzer, H., The emission-line regions of high-redshift QSOs, Astrophys. J., 1978, 226: 1.［20］Wills, B. J., Thompson, K. L., Han, M. et al. , The Hubble space telescope sample of radio-loud quasars: Ultraviolet spectra of the first 31 quasars, Astrophys. J., 1995, 447: 139.［21］Osmer, P. S., Smith, M. G. , Discovery and spectroscopic observations of 27 optical selected quasars with 1.4 ＜ z ＜ 2.5,Astrophys. J., 1977, 213: 607.［22］Storrie-Lombardi, L. J., McMabon, R. G., Irwin, M. J. et al., APM Z ＞ = 4 QSO Survey: Spectra and Intervening Ab-sorption Systems, Astrophys. J., 1996, 468: 121.［23］Young, P. , Sargent, W. L. W. , Boksenberg, A. , Clv absorption in an unbiased sample of 33 QSOs: evidence for the inter-vening galaxy hypothesis, Astrophys. J. Suppl., 1982, 48: 455.［24］Zitelli, V., Mignoli, M., Zarano, B. et al., A spectroscopically complete sample of quasars with Bj ≤ 22
Santos, N. C.; Santerne, A.; Faria, J. P.; Rey, J.; Correia, A. C. M.; Laskar, J.; Udry, S.; Adibekyan, V.; Bouchy, F.; Delgado-Mena, E.; Melo, C.; Dumusque, X.; Hébrard, G.; Lovis, C.; Mayor, M.; Montalto, M.; Mortier, A.; Pepe, F.; Figueira, P.; Sahlmann, J.; Ségransan, D.; Sousa, S. G.
2016-07-01
Context. With about 2000 extrasolar planets confirmed, the results show that planetary systems have a whole range of unexpected properties. This wide diversity provides fundamental clues to the processes of planet formation and evolution. Aims: We present a full investigation of the HD 219828 system, a bright metal-rich star for which a hot Neptune has previously been detected. Methods: We used a set of HARPS, SOPHIE, and ELODIE radial velocities to search for the existence of orbiting companions to HD 219828. The spectra were used to characterise the star and its chemical abundances, as well as to check for spurious, activity induced signals. A dynamical analysis is also performed to study the stability of the system and to constrain the orbital parameters and planet masses. Results: We announce the discovery of a long period (P = 13.1 yr) massive (m sini = 15.1 MJup) companion (HD 219828 c) in a very eccentric orbit (e = 0.81). The same data confirms the existence of a hot Neptune, HD 219828 b, with a minimum mass of 21 M⊕ and a period of 3.83 days. The dynamical analysis shows that the system is stable, and that the equilibrium eccentricity of planet b is close to zero. Conclusions: The HD 219828 system is extreme and unique in several aspects. First, ammong all known exoplanet systems it presents an unusually high mass ratio. We also show that systems like HD 219828, with a hot Neptune and a long-period massive companion are more frequent than similar systems with a hot Jupiter instead. This suggests that the formation of hot Neptunes follows a different path than the formation of their hot jovian counterparts. The high mass, long period, and eccentricity of HD 219828 c also make it a good target for Gaia astrometry as well as a potential target for atmospheric characterisation, using direct imaging or high-resolution spectroscopy. Astrometric observations will allow us to derive its real mass and orbital configuration. If a transit of HD 219828 b is detected
Ghosh, Swarnava
2016-01-01
As the second component of SPARC (Simulation Package for Ab-initio Real-space Calculations), we present an accurate and efficient finite-difference formulation and parallel implementation of Density Functional Theory (DFT) for periodic systems. Specifically, employing a local formulation of the electrostatics, the Chebyshev polynomial filtered self-consistent field iteration, and a reformulation of the non-local force component, we develop a finite-difference framework wherein both the energy and atomic forces can be efficiently calculated to within chemical accuracies. We demonstrate using a wide variety of materials systems that SPARC obtains high convergence rates in energy and forces with respect to spatial discretization to reference plane-wave result; energies and forces that are consistent and display negligible `egg-box' effect; and accurate ground-state properties. We also demonstrate that the weak and strong scaling behavior of SPARC is similar to well-established and optimized plane-wave implementa...
Trushin, Egor; Betzinger, Markus; Blügel, Stefan; Görling, Andreas
2016-08-01
An approach to calculate fundamental band gaps, ionization energies, and electron affinities of periodic electron systems is explored. Starting from total energies obtained with the help of the adiabatic-connection fluctuation-dissipation (ACFD) theorem, these physical observables are calculated according to their basic definition by differences of the total energies of the N -, (N -1 ) -, and (N +1 ) -electron system. The response functions entering the ACFD theorem are approximated here by the direct random phase approximation (dRPA). For a set of prototypical semiconductors and insulators it is shown that even with this quite drastic approximation the resulting band gaps are very close to experiment and of a similar quality to those from the computationally more involved G W approximation. By going beyond the dRPA in the future the accuracy of the calculated band gaps may be significantly improved further.
Dolan, Elizabeth A; Venable, Richard M; Pastor, Richard W; Brooks, Bernard R
2002-01-01
We demonstrate the ease and utility of simulating heterogeneous interfacial systems with P2(1) and Pc periodic boundary conditions which allow, for example, lipids in a membrane to switch leaflets. In preliminary tests, P2(1) was shown to yield equivalent results to P1 in simulations of bulk water, a water/vacuum interface, and pure DPPC bilayers with an equal number of lipids per leaflet; equivalence of Pc and P1 was also demonstrated for the former two systems. P2(1) was further tested in simulations involving the spreading of an octane film on water, and equilibration of a DPPC bilayer from an initial condition containing different numbers of lipids in the two leaflets. Lastly, a simulation in P2(1) of a DOPC/melittin membrane showed significant passage of lipids to the melittin-containing leaflet from the initial distribution, and lends insight into the condensation of lipids by melittin. PMID:11964222
Directory of Open Access Journals (Sweden)
Drogomiretskaya M.S.
2016-03-01
Full Text Available Anomalies and deformation of dental system in children and adolescents contribute not only to the deterioration of dental health, bat quite often this is the cause of a wide range of somatic pathology. The aim of our study was to determine risk factors of dental system myofunctional disorders in children with impaired course of the antenatal period using morphological and morphometric studies. The changes that have been defined in the organs examined were dystrophic and dyscirculatory and differed in degrees of severity in all parts of the oral cavity. Dystrophic changes were detected in the gums and tongue epithelium. Dyscirculatory disorders were characterized by formation of submucosal edema, development of the vascular bed hyperemia and presence of hemorrhage under the basement membrane of the epithelium and salivary gland stroma. Pronounced changes were recorded in the nerve cells of the oral cavity.
Molinaro, R.; Ripepi, V.; Marconi, M.; Bono, G.; Lub, J.; Pedicelli, S.; Pel, J. W.
2011-01-01
We present a new derivation of the CORS Baade-Wesselink method in the Walraven photometric system. We solved the complete Baade-Wesselink equation by calibrating the surface brightness function with a recent grid of atmosphere models. The new approach was adopted to estimate the mean radii of a samp
Kang-Kang, Wang; Xian-Bin, Liu; Yu, Zhou
2015-08-01
In this paper, the stability and stochastic resonance (SR) phenomenon induced by the multiplicative periodic signal for a metapopulation system driven by the additive Gaussian noise, multiplicative non-Gaussian noise and noise correlation time is investigated. By using the fast descent method, unified colored noise approximation and McNamara and Wiesenfeld’s SR theory, the analytical expressions of the stationary probability distribution function and signal-to-noise ratio (SNR) are derived in the adiabatic limit. Via numerical calculations, each effect of the addictive noise intensity, the multiplicative noise intensity and the correlation time upon the steady state probability distribution function and the SNR is discussed, respectively. It is shown that multiplicative, additive noises and the departure parameter from the Gaussian noise can all destroy the stability of the population system. However, the noise correlation time can consolidate the stability of the system. On the other hand, the correlation time always plays an important role in motivating the SR and enhancing the SNR. Under different parameter conditions of the system, the multiplicative, additive noises and the departure parameter can not only excite SR phenomenon, but also restrain the SR phenomenon, which demonstrates the complexity of different noises upon the nonlinear system.
International Nuclear Information System (INIS)
The T-15 cryogenics system has been designed for cooling down, cryostatting, warming up of superconducting, cryoresistive and cryogenics T-15 objects. Maintenance of the cryogenics system has been on going since 1988. For the mentioned period, in the cryogenics T-15 system. The capacity of screw compressor was increased from 0.181 kg/s to 0.236 kg/s (third stage compressors with increased capacity were developed and manufactured), their reliability was also enhanced. The capacity of liquefiers was increased from 0.0833 - 0.0972 L/s (300-350 L/h) to 0.222 L/s (800 L/h) due to replacement of turboexpanders by more effective ones and due to introduction of an end-stage turboexpander into maintenance. The heat influxes to the cryogenics pipelines were reduced by 50%. For the same period some technological regimes of cryogenics system have been developed to produce the maximal output of cold. The cooling down from 110 K to 15 K is done, when one or two liquefiers are in operation under refrigerating conditions with the reverse flow splitting. The further cooling is performed under joint operation of two liquefiers; one of them operates in the liquefying mode, another, in the refrigerating one with excess reverse flow. A change in the operating conditions was necessary because of the impossibility of regulating the distribution of the reverse helium flow between two liquefiers at the temperature below 15K. The main regime at the level of 4.5 K is a two-loop operating diagram, when one liquefier and a passive refrigerator with excessive reverse flow are in operation, the refrigerating capacity is about 3 kW
On the Systematic Error in the Quantum Mechanical Calculations to the Periodic Table of Elements
Khazan, Albert
2011-05-01
The scientists working on the problems of the Periodic Table of Elements regularly attempt to create models of the elements on the basis of the laws of Quantum Mechanics. One even attempted to use the calculation of the dependency ``atomic mass - element's number'' on this basis, in order to extend the Table by introducing two new Periods containing 50 elements each. The hyperbolic law we have found in the Periodic Table allows to find, first, the atomic mass of the last (heaviest stable) element (411.66), then - the number of the protons in it (155). Two functions were compared: the IUPAC 2007 function (elements 80-118) and another one created according the other data (elements 80-224). Both functions have a large deviation of data in No.104-118. Commencing in Period 8, there are three ``shifts'' of atomic mass for 17, 20, and 25 AMU. Also, our analysis manifests that there in all the aforementioned data is a single point with atomic mass 412 and number 155, where the parameters meet each other. This fact verifies our theory (Khazan A. Upper Limit in Mendeleev's Periodic Table - Element No.155. 2nd ed., Svenska fysikarkivet, Stockholm, 2010).