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1

The Different Periodic Tables of Dmitrii Mendeleev  

Science.gov (United States)

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…

Laing, Michael

2008-01-01

2

Novelty, coherence, and Mendeleev's periodic table.  

Science.gov (United States)

Predictivism is the view that successful predictions of "novel" evidence carry more confirmational weight than accommodations of already known evidence. Novelty, in this context, has traditionally been conceived of as temporal novelty. However temporal predictivism has been criticized for lacking a rationale: why should the time order of theory and evidence matter? Instead, it has been proposed, novelty should be construed in terms of use-novelty, according to which evidence is novel if it was not used in the construction of a theory. Only if evidence is use-novel can it fully support the theory entailing it. As I point out in this paper, the writings of the most influential proponent of use-novelty contain a weaker and a stronger version of use-novelty. However both versions, I argue, are problematic. With regard to the appraisal of Mendeleev' periodic table, the most contentious historical case in the predictivism debate, I argue that temporal predictivism is indeed supported, although in ways not previously appreciated. On the basis of this case, I argue for a form of so-called symptomatic predictivism according to which temporally novel predictions carry more confirmational weight only insofar as they reveal the theory's presumed coherence of facts as real. PMID:24984451

Schindler, Samuel

2014-03-01

3

Interaction properties of ytterbium with elements of Mendeleev periodic table  

International Nuclear Information System (INIS)

This article presents the new data on ytterbium interaction with elements of Mendeleev periodic table. The state diagrams of ytterbium with magnesium, calcium, strontium, and barium are constructed. The state diagrams of ytterbium with Cu, Ag, Au, Zn, Cd, Hg, B,Al, Ga, In, Tl are considered.

4

Regularities of change of ultrasound propagation rate in melts of simple substances in relation to position of elements in D.I.Mendeleev's Periodic System  

International Nuclear Information System (INIS)

Experimental data on the rate of elastic wave propagation vs in the melts of simple substances (Cs,Sr,In,Cd,Te, in particular) are generalized on the basis of the Laplace modified equation and D.I.Mendeleev Periodic Law. Regularity in the change of vs value in the subgroups of the Periodic Law is detected, ultrasound propagation rate in the melts of francium, radium and beryllium at the corresponding melting points are forecasted. Microheterogeneous structure of certain electron melts is confirmed

5

Energy capacity of elements in periodic table of D.I.Mendeleev  

International Nuclear Information System (INIS)

A great difference in the intensity of heat constent variation from one element to another is detected. The notion of energy capacity of elements is introduced. It is an energy characteristic, determining arrangement of elements in the D.I.Mendeleev Periodic system. The value of energy capacity depends on external conditions (temperature, pressure, etc.). Lanthanides and actinides are systematized on the basis of their energy capacity, atomic mass and melting points. It is shown, that energy capcity, determining element location in thePeriodic system, characterizes the intensity of their energy state variation. Energy state of monocomponent systems with any mass number determines their physicomechanical properties

6

Additional Explanations to "Upper Limit in Mendeleev’s Periodic Table - Element No.155". A Story How the Problem was Resolved  

Directory of Open Access Journals (Sweden)

Full Text Available This paper gives a survey for the methods how a possible upper limit in Mendeleev's Periodic Table can be found. It is show, only the method of hyperbolas leads to exact answering this question.

Khazan A.

2009-07-01

7

From the Mendeleev periodic table to particle physics and back to the periodic table  

International Nuclear Information System (INIS)

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)

8

From the Mendeleev periodic table to particle physics and back to the periodic table  

Energy Technology Data Exchange (ETDEWEB)

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)

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

9

Investigating Patterns: An introduction to Mendeleev, periodicity, and the Periodic Table  

Science.gov (United States)

This activity is a puzzle where students organize samples and look for patterns in order to predict properties of missing puzzle pieces. The students then relate their experience to the historical development of the Periodic Table and the ways that the Periodic Table can be used to predict the properties of the elements.

Hogan, Jennifer

10

The comparison of element composition of Venus, Earth, Mars, and chondrites in the light of the Mendeleev Periodic Law  

International Nuclear Information System (INIS)

The share of free neutral atoms, N0, for all elements in Protoplanet nebula has been determined with the account of their abundance and physico-chemical properties. The linear dependence for the ratio of nonvolatile and volatile elements in chondrites and igneous rocks of the Earth on N0 was obtained. The Mendeleev Periodic Law was used to obtain the proof of the existence of the hypothetical process of element magnetic separation in Protoplanet nebula. To this end the concentration ratios of element-analogous with different N0 in the matters of Venus, Earth, Mars, and chondrites were compared. The data obtained are sufficient demonstration of the existence of the hypothetical process of element magnetic separation in Protoplanet nebula. With the account of the above said, it was shown that Shergotty and Tunguska meteorites by their relative elemental composition are close to Mars and asteroids, respectively. (author)

11

Superconductivity, antiferromagnetism and ferromagnetism in periodic table of D.I. Mendeleev  

International Nuclear Information System (INIS)

Definite regularity in the distribution of ferromagnetic, antiferromagnetic and superconducting elements is observed in the periodic table starting with the 4th period. Elements with superconductivity, by which d-shells start to fill up, are at the beginning of each period; then follow antiferromagnetics and ferromagnetics (in 4th period and lanthanides), or elements without any of the three listed order types (5th period and 6th period), in which the d (f)-shells continue to fill up almost exceedingly; then again appear superconductors by filling the p-shell up to the number is equal to 4. We calculated the radii of the external d (f)- and p-orbitals and the nearest to them orbitals with the Slater method. These trends were explained by distinction of degree of division of the external d (f)- or p-orbitals of the neighboring atoms in the crystal. Largest division occurs in ferromagnetics. In antiferromagnetics it is smaller than in ferromagnetics. It is demonstrated that in the superconducting crystals the external dor p-shells approach the nucleus of neighboring atoms are much closely those for ferromagnetic or antiferromagnetic crystals. Furthermore the external d- or p-shells of some elements in the 5th and 6th periods approach the deeper shells of neighboring atoms. Hence the electron in this shell is situated in neighboring atoms in a different electric field from its own. This fact is open to speculation that the separation of spin and charge in electron, disposed on the external d- or p-orbitals, is quite possible. The charges without spin become bosons. Spins that have the magnetic moments are ordered antiparallel in pairs. Magnetic field transfers this pair in a parallel state and a magnetic flux component along of magnetic field from the pair is equal to one fluxon (the quant of the magnetic flux).

12

XVIII Mendeleev congress on general and applied chemistry. Summaries of reports in five volumes. Volume 5. IV Russian-French symposium Supramolecular systems in chemistry and biology. II Russian-Indian symposium on organic chemistry. International symposium on present-day radiochemistry Radiochemistry: progress and prospects. International symposium Green chemistry, stable evolution and social responsibility of chemists. Symposium Nucleophilic hydrogen substitution in aromatic systems and related reactions  

International Nuclear Information System (INIS)

The 5 volume of the XVIII Mendeleev congress on general and applied chemistry includes summaries of reports on the subjects of sypramolecular systems in chemistry and biology, organic chemistry, modern radiochemistry, green chemistry - development and social responsibility of chemists, nucleophilic hydrogen substitution in aromatic systems and related chemical reactions

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From the other oil field : Mendeleev, the West and the Russian oil industry (Dmitrii Ivanovich Mendeleev)  

Energy Technology Data Exchange (ETDEWEB)

This thesis examined five business trips of the Russian chemist, Dmitrii Ivanovich Mendeleev to determine if he was open to Western ideas and capital in the Russian petroleum industry. His voyages to France, the United States, and the Caucasus took place between 1863 and 1886. Each trip produced published articles along with personal letters and diaries. This study examines both published and unpublished archival documents to reveal the history of the petroleum industry, its industrialists and Mendeleev's personality. The first chapter of the thesis summarizes Mendeleev's formative years before he entered the oil industry in 1863, when his youthful travels and studies within Europe rendered him multi-lingual and worldly-wise. The remaining chapters examined Mendeleev's trips in which he explored the petroleum industry. A special recount of his final years was included. It was concluded that contrary to Soviet judgement, Mendeleev was open to the West, with his only requirement being that Western ideas and capital help with the growth of the Russian oil industry and result in the abundant supply of inexpensive kerosene for the Russian people.

Butorac, M.J.F.

2002-07-01

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XVII Mendeleev congress on general and applied chemistry. Summary of reports. Volume 4. Russian-French symposium Supramolecular systems in chemistry and biology. Chemical education. Russian-American symposium on chemical education. Biomolecular chemistry and biotechnology. Petrochemistry and catalysis. Symposium devoted to centenary from discovery of chromatography by M.S. Tsvet  

International Nuclear Information System (INIS)

Reports of the XVII Mendeleev congress on general and applied chemistry, volume 4 (Kazan', 21 - 26 September, 2003) are presented. Current status and prospects of chemical science, biomolecular chemistry and biotechnology, petrochemistry and catalysis, chemical education, as well as some ecological problems are treated in the collection. Materials of the Russian-French symposium: Supramolecular systems in chemistry and biology, Russian-American symposium on chemical education as well as symposium devoted to the 100 anniversary from the discovery of chromatography by Russian scientist M.S. Tsvet are included in the volume. Prospects for the development of chromatography and applications of this method are discussed

15

The Periodic Table in Croatia  

Directory of Open Access Journals (Sweden)

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.

Raos, N.

2011-12-01

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Tectonic pattern of the Mendeleev Ridge and adjacent basins: results of joint analysis of potential fields and recent Russian seismic data  

Science.gov (United States)

The work was performed under Russian Federation State Geological mapping at a scale of 1:1 000 000 and UNCLOS programs. The study area is located between 76N-84N and 156E-168W and covers the Mendeleev Ridge, adjacent Podvodnikov, Mendeleev, Chukchi Basins and northern part of the East-Siberian Sea shelf. It is characterized by very poor magnetic and gravity data coverage. Majority of airborne magnetic and on-ice gravity surveys were carried out in the region about 40 years ago and have low spatial resolution and poor navigation. Seismic data collected earlier in the study area are presented by sparse lines of historical seismic reflection soundings and by results of deep seismic refraction and reflection observations along several geotransects. Hence, conclusions concerning tectonic structure and spatial relation of the Mendeleev Ridge with adjacent geological structures up to present day remain speculative. Joint analysis of recent seismic reflection and refraction data collected during Russian expeditions «Arctic-2011» and «Arctic-2012» with mentioned above geophysical information allowed to clarify the contours of geological structures in the study area and reveal some new peculiarities of their tectonic pattern. Particularly complex tectonic structure of the Mendeleev Ridge, changing from it's southern to the northern part and represented by two main systems of tectonic displacements is discovered. The first fault system comprises horsts/graben-bounding faults oriented preferably in N-S direction. The second system is presented by faults of NW-SE direction disturbing the first one. In the southern part of the Mendeleev Ridge such faults are the strike-slip faults with small horizontal displacements. Starting from the central part of the ridge and further to the north, displacements along strike-slip faults become progressively more pronounced and have sinistral character. In the northern part of the ridge a pull-apart structures are recognized which presumably correspond to the transitional shear zone between the Mendeleev and the Alpha ridges. Mentioned above features indicate that existed earlier as a single structure the Alpha-Mendeleev Ridge was exposed to transtension. As a result it was separated later by the shear zone on two ridges which moved from each other with forming the system of NW-SE left-lateral strike-slip (oblique-slip) faults. Some more details and speculations concerning the tectonic pattern of the Mendeleev Ridge and adjacent structures will be offered in presentation.

Chernykh, Andrey; Astafurova, Ekaterina; Korneva, Maria; Egorova, Alena; Redko, Anton; Glebovsky, Vladimir

2014-05-01

17

Superheavy elements in D I Mendeleev's Periodic Table  

International Nuclear Information System (INIS)

The results on the synthesis of new superheavy elements, synthesized in complete fusion reactions of 48Ca ions with actinide targets, are summarized and analyzed. The perspectives for the synthesis of element 117, as well as of elements with Z?118 are also considered.

18

Adaptive control of periodic systems  

Science.gov (United States)

Adaptive control is needed to cope with parametric uncertainty in dynamical systems. The adaptive control of LTI systems in both discrete and continuous time has been studied for four decades and the results are currently used widely in many different fields. In recent years, interest has shifted to the adaptive control of time-varying systems. It is known that the adaptive control of arbitrarily rapidly time-varying systems is in general intractable, but systems with periodically time-varying parameters (LTP systems) which have much more structure, are amenable to mathematical analysis. Further, there is also a need for such control in practical problems which have arisen in industry during the past twenty years. This thesis is the first attempt to deal with the adaptive control of LTP systems. Adaptive Control involves estimation of unknown parameters, adjusting the control parameters based on the estimates, and demonstrating that the overall system is stable. System theoretic properties such as stability, controllability, and observability play an important role both in formulating of the problems, as well as in generating solutions for them. For LTI systems, these properties have been studied since 1960s, and algebraic conditions that have to be satisfied to assure these properties are now well established. In the case of LTP systems, these properties can be expressed only in terms of transition matrices that are much more involved than those for LTI systems. Since adaptive control problems can be formulated only when these properties are well understood, it is not surprising that systematic efforts have not been made thus far for formulating and solving adaptive control problems that arise in LTP systems. Even in the case of LTI systems, it is well recognized that problems related to adaptive discrete-time system are not as difficult as those that arise in the continuous-time systems. This is amply evident in the solutions that were derived in the 1980s and 1990s for all the important problems. These differences are even more amplified in the LTP case; some problems in continuous time cannot even be formulated precisely. This thesis consequently focuses primarily on the adaptive identification and control of discrete-time systems, and derives most of the results that currently exist in the literature for LTI systems. Based on these investigations of discrete-time adaptive systems, attempts are made in the thesis to examine their continuous-time counterparts, and discuss the principal difficulties encountered. The dissertation examines critically the system theoretic properties of LTP systems in Chapter 2, and the mathematical framework provided for their analysis by Floquet theory in Chapter 3. Assuming that adaptive identification and control problems can be formulated precisely, a unified method of developing stable adaptive laws using error models is treated in Chapter 4. Chapter 5 presents a detailed study of the adaptation in SISO discrete-time LTP systems, and represents the core of the thesis. The important problems of identification, stabilization, regulation, and tracking of arbitrary signals are investigated, and practically implementable stable adaptive laws are derived. The dissertation concludes with a discussion of continuous-time adaptive control in Chapter 6 and discrete multivariable systems in Chapter 7. Directions for future research are indicated towards the end of the dissertation.

Tian, Zhiling

19

Stratigraphy, Structure, and Origin; A Geophysical Survey of the Mendeleev Ridge  

Science.gov (United States)

The Mendeleev Ridge is a broad, aseismic ridge that extends from the Siberian Shelf into the central Arctic Ocean. While it is continuous with the Alpha Ridge and is inferred to be an oceanic plateau, it may have had a distinct and separate history. The origin of the Mendeleev ridge has only rarely been visited and, as a result, understanding the history of this region has largely been based on the presumption of a common origin for both features. In late summer 2005, a geophysical survey was conducted from USCGC Healy over the Mendeleev Ridge as part of a trans-arctic crossing. During this survey ~730 km of seismic reflection data was recovered over the ridge along with co-registered gravity and bathymetry data and seismic refraction profiles. The seismic source was two 250 cu in G-guns. The streamer length was limited by ice conditions to 300 meters. Wear and tear caused by towing the streamer through the ice pack eliminated hydrophones, so the number of active channels ranged from 24 to as few as 11. The seismic reflection data requires significant trace editing to eliminate random electrical noise and frequency-wave number filtering to eliminate low velocity noise caused by the streamer traveling through heavy ice. After trace editing the data are stacked and migrated with constant water velocity. Stacking velocities are used as input into initial ray tracing models. Derived boundary velocities from ray tracing models will be reapplied to the migration of reflection data and are converted through empirical relationships into densities, and used as input into gravity models. Brute stacked reflection images of the Mendeleev Ridge reveal pervasive extensional faulting of the basement and lower sediment layers, and a continuous, undeformed pelagic sediment layer mantling the ridge, indicative of recent tectonic inactivity. The age of the unconformity underlying this layer should date the end of significant deformation of the Alpha and Mendeleev Ridges. Consistency of modeled seismic velocities from the upper basement will provide some insight into the nature of the crustal material. Upper basement velocities estimated from the sonobuoy data range from 3.7-5.0 km/s, suggestive of a heterogeneous upper crust. Initial gravity models suggest that much of the amplitude variation over the Mendeleev Ridge is accommodated by invoking a single, continuous density layer for the crust. Future work will include: developing a structural map of the Mendeleev ridge as well as the refining of both the ray-tracing and gravity modeling in an attempt to better understand the crustal style of the ridge.

Dove, D.; Coakley, B.; Hopper, J.

2006-12-01

20

Half-Period Excitations in Continuum Periodic Systems  

CERN Document Server

We investigate the generation of half-period states in continuum periodic systems. As a prototypical example, we use a trapped Bose-Einstein condensate confined in a periodic optical-lattice potential. We show that when the potential is turned on sufficiently nonadiabatically, the system tries to reach its new ground state by transiting through states with periodicity half that of the lattice. The particularly intriguing characteristic of such states is that they cannot be captured by discrete systems such as the discrete nonlinear Schr{\\"o}dinger equation. We illustrate the origin of these states mathematically by treating them as superharmonic resonances of a parametrically forced Duffing oscillator and discuss their transient nature and potential observability.

Nistazakis, H E; Kevrekidis, P G; Frantzeskakis, D J; Nicolin, A; Chin, J K; Porter, Mason A.

2005-01-01

 
 
 
 
21

Asymptotic Behavior of a Periodic Diffusion System  

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Full Text Available Abstract We study the asymptotic behavior of the nonnegative solutions of a periodic reaction diffusion system. By obtaining a priori upper bound of the nonnegative periodic solutions of the corresponding periodic diffusion system, we establish the existence of the maximum periodic solution and the asymptotic boundedness of the nonnegative solutions of the initial boundary value problem.

Li Songsong

2010-01-01

22

Origin of the Periodic Table  

Science.gov (United States)

This site provides a description of the development of the periodic table by Dmitri Mendeleev based on weight and common physical and chemical properties. An overview of the tableâs organization scheme is contained along with links to information about the Schrödinger and Rutherford atomic models. More information about Mendeleevâs methods and the chemistry of his time are also provided.

2006-12-25

23

Optimal periodic orbits of chaotic systems occur at low period  

International Nuclear Information System (INIS)

Invariant sets embedded in a chaotic attractor can generate time averages that differ from the average generated by typical orbits on the attractor. Motivated by two different topics (namely, controlling chaos and riddled basins of attraction), we consider the question of which invariant set yields the largest (optimal) value of an average of a given smooth function of the system state. We present numerical evidence and analysis that indicate that the optimal average is typically achieved by a low-period unstable periodic orbit embedded in the chaotic attractor. In particular, our results indicate that, if we consider that the function to be optimized depends on a parameter ?, then the Lebesgue measure in ? corresponding to optimal periodic orbits of period p or greater decreases exponentially with increasing p. Furthermore, the set of parameter values for which optimal orbits are nonperiodic typically has zero Lebesgue measure. copyright 1996 The American Physical Society

24

New data on the age of dolerites and basalts of Mendeleev Rise (Arctic Ocean)  

Science.gov (United States)

We present results of 40Ar/39Ar isotopic investigations concerning the dating of dolerites and basalts that were sampled during the Arctica-2012 polar expedition. Basalts were sampled by means of deep underwater drilling with wells up to 2 m in outcrops on the seafloor (basalts), and dolerite samples were obtained from the bottom of an escarp of Mendeleev Rise using a manipulator on the research submarine. The analysis results of the obtained mono-mineral fractions (amphibole, plagioclase, pyroxene) from the studied rocks yielded an Early Paleozoic age of the dolerites and basalts from Mendeleev Rise. The oldest ages obtained for amphibole reach 471.5 ± 18.1 and 466.9 ± 3.3 Ma, which corresponds to the Early-Middle Ordovician. The isotopic composition of argon was measured on two mass spectrometers: the Micromass Noble Gas 5400 (UK) and the Thermo Scientific Argus (Germany). The determined Early Paleozoic age of igneous rocks of Mendeleev Rise and seismic data obtained during the last Russian expedition Arctica-2012 [2] let us suppose that this continental block of the Earth's crust has a Precambrian basement similar to the basement identified for the New Siberian islands including the De Long archipelago.

Vernikovsky, V. A.; Morozov, A. F.; Petrov, O. V.; Travin, A. V.; Kashubin, S. N.; Shokal'sky, S. P.; Shevchenko, S. S.; Petrov, E. O.

2014-02-01

25

Late Quaternary sediment deposition of core MA01 in the Mendeleev Ridge, the western Arctic Ocean: Preliminary results  

Science.gov (United States)

Late Quaternary deep marine sediments in the Arctic Ocean are characterized by brown layers intercalated with yellowish to olive gray layers (Poore et al., 1999; Polyak et al., 2004). Previous studies reported that the brown and gray layers were deposited during interglacial (or interstadial) and glacial (or stadial) periods, respectively. A 5.5-m long gravity core MA01 was obtained from the Mendeleev Ridge in the western Arctic Ocean by R/V Xue Long during scientific cruise CHINARE-V. Age (~450 ka) of core MA01 was tentatively estimated by correlation of brown layers with an adjacent core HLY0503-8JPC (Adler et al., 2009). A total of 22 brown layers characterized by low L* and b*, high Mn concentration, and abundant foraminifera were identified. Corresponding gray layers are characterized by high L* and b*, low Mn concentration, and few foraminiferal tests. Foraminifera abundance peaks are not well correlated to CaCO3 peaks which occurred with the coarse-grained (>0.063 mm) fractions (i.e., IRD) both in brown and gray layers. IRDs are transported presumably by sea ice for the deposition of brown layers and by iceberg for the deposition of gray layers (Polyak et al., 2004). A strong correlation coefficient (r2=0.89) between TOC content and C/N ratio indicates that the major source of organic matter is terrestrial. The good correlations of CaCO3 content to TOC (r2=0.56) and C/N ratio (r2=0.69) imply that IRDs contain detrital CaCO3 which mainly originated from the Canadian Arctic Archipelago. In addition, high kaolinite/chlorite (K/C) ratios mostly correspond to CaCO3 peaks, which suggests that the fine-grained particles in the Mendeleev Ridge are transported from the north coast Alaska and Canada where Mesozoic and Cenozoic strata are widely distributed. Thus, the Beaufort Gyre, the predominant surface current in the western Arctic Ocean, played an important role in the sediment delivery to the Mendeleev Ridge. It is worthy of note that the TOC and CaCO3 peaks are obviously distinct in the upper part of core MA01, whereas these peaks are reduced in the lower part of the core. More study on these contrasting features is in progress. References Adler, R.E., Polyak, L., Ortiz, J.D., Kaufman, D.S., Channell, J.E.T., Xuan, C., Grottoli, A.G., Sellén, E., and Crawford, K.A., 2009. Global and Planetary Change 68(1-2), 18-29. Polyak, L., Curry, W.B., Darby, D.A., Bischof, J., and Cronin, T.M., 2004. Palaeogeography, Palaeoclimatology, Palaeoecology 203, 73-93. Poore, R., Osterman, L., Curry, W., and Phillips, R., 1999. Geology 27, 759-762.

Park, Kwang-Kyu; Kim, Sunghan; Khim, Boo-Keun; Xiao, Wenshen; Wang, Rujian

2014-05-01

26

Periodic Solutions for Subquadratic Discrete Hamiltonian Systems  

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Full Text Available Some existence conditions of periodic solutions are obtained for a class of nonautono mous subquadratic first-order discrete Hamiltonian systems by the minimax methods in the critical point theory.

Deng Xiaoqing

2007-01-01

27

Periodic Solutions for Subquadratic Discrete Hamiltonian Systems  

Directory of Open Access Journals (Sweden)

Full Text Available Some existence conditions of periodic solutions are obtained for a class of nonautono mous subquadratic first-order discrete Hamiltonian systems by the minimax methods in the critical point theory.

Xiaoqing Deng

2007-06-01

28

Phase splitting for periodic Lie systems  

Energy Technology Data Exchange (ETDEWEB)

In the context of the Floquet theory, using a variation of parameter argument, we show that the logarithm of the monodromy of a real periodic Lie system with appropriate properties admits a splitting into two parts called dynamic and geometric phases. The dynamic phase is intrinsic and linked to the Hamiltonian of a periodic linear Euler system on the co-algebra. The geometric phase is represented as a surface integral of the symplectic form of a co-adjoint orbit.

Flores-Espinoza, R; Vorobiev, Yu M [Departamento de Matematicas, Universidad de Sonora (Mexico); De Lucas, J, E-mail: rflorese@gauss.mat.uson.m, E-mail: delucas@impan.gov.p, E-mail: yurimv@guaymas.uson.m [Departamento de Fisica Teorica, Universidad de Zaragoza (Spain)

2010-05-21

29

Phase splitting for periodic Lie systems  

Science.gov (United States)

In the context of the Floquet theory, using a variation of parameter argument, we show that the logarithm of the monodromy of a real periodic Lie system with appropriate properties admits a splitting into two parts called dynamic and geometric phases. The dynamic phase is intrinsic and linked to the Hamiltonian of a periodic linear Euler system on the co-algebra. The geometric phase is represented as a surface integral of the symplectic form of a co-adjoint orbit.

Flores-Espinoza, R.; de Lucas, J.; Vorobiev, Yu M.

2010-05-01

30

Phase splitting for periodic Lie systems  

International Nuclear Information System (INIS)

In the context of the Floquet theory, using a variation of parameter argument, we show that the logarithm of the monodromy of a real periodic Lie system with appropriate properties admits a splitting into two parts called dynamic and geometric phases. The dynamic phase is intrinsic and linked to the Hamiltonian of a periodic linear Euler system on the co-algebra. The geometric phase is represented as a surface integral of the symplectic form of a co-adjoint orbit.

31

Bathymetry, controlled source seismic and gravity observations of the Mendeleev ridge; implications for ridge structure, origin, and regional tectonics  

Science.gov (United States)

Multichannel seismic (MCS), seismic refraction, and gravity data collected down the flank of the Chukchi Plateau, but predominantly over the Mendeleev Ridge have been processed and interpreted to describe the crustal style of the ridge, as well as the structural history. These results provide constraints on the origin of the ridge, and the tectonic evolution of the Amerasian Basin. MCS images reveal two primary sediment sequences separated by an unconformity that persists across the entire Mendeleev Ridge. The basement and lower sediment sequence exhibit pervasive normal faulting. The upper sequence is laterally conformable and not effected by faulting, thus the regional unconformity dividing the two sequences is interpreted to mark the end of extensional deformation. Modeling of sonobuoy seismic refraction data reveals upper crustal P-wave velocities ranging from 3.5 to 6.4kms-1 approximately 5km into the basement. The velocity structure of the Mendeleev Ridge is consistent with either a volcanic rifted continental margin, or an oceanic plateau origin. Observed gravity anomalies over the ridge are reproduced by a model consisting of bathymetry, sediment and basement horizons from the MCS data and a single crustal layer of 2.86gcm-3. This result is consistent with homogeneous, mafic crust. The similar velocity and density structures of the Mendeleev and Alpha ridges is consistent with a model where the two ridges are contiguous and share a common geological origin. Gravity modelling over the transition between the Chukchi Plateau and the Mendeleev Ridge suggests the two features have differing compositions and distinct emplacement histories. Three tectonic models are presented for the origin of the Alpha Mendeleev Ridge (AMR) that satisfy constraints set by this and previous studies: (1) a rifted volcanic continental margin, (2) an oceanic plateau formed at a spreading centre-perpendicular to the AMR and (3) an oceanic plateau formed at a spreading centre-parallel to the AMR.

Dove, Dayton; Coakley, Bernard; Hopper, John; Kristoffersen, Yngve

2010-11-01

32

The nature of the acoustic basement on Mendeleev and northwestern Alpha ridges, Arctic Ocean  

Science.gov (United States)

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.

Bruvoll, Vibeke; Kristoffersen, Yngve; Coakley, Bernard J.; Hopper, John R.; Planke, Sverre; Kandilarov, Aleksandre

2012-01-01

33

Orbital stability for the periodic Zakharov system  

International Nuclear Information System (INIS)

In this work we prove the existence of a smooth curve of periodic travelling wave solutions of dnoidal type for the one-dimensional Zakharov system. We also show that this type of solution is orbitally stable by periodic perturbations of the same wavelength as the underlying wave. As a consequence of our stability approach, we give an analysis of the stability parameters. We also give other proof of the orbital stability of the well-known solitary wave profiles. We hope that the techniques employed may be of further use in the study of the stability of periodic travelling wave solutions for other nonlinear evolution equations

34

Multichannel long period seismic data acquisition system  

International Nuclear Information System (INIS)

This paper discusses the specifications and performance of an eight channel long period seismic digital data acquisition system, which is developed and installed at Seismic Array Station, Gauribidanur, Karnataka State. The paper describes how these data in an unedited form are recorded on a single track of magnetic tape inter-mittantly, which has resulted in recording of 50 days data on a single tapespool. A time indexing technique which enables quick access to any desired portion of a recorded tape is also discussed. Typical examples of long period seismic event signals recorded by this system are also illustrated. Various advantages, the system provides over the analog multichannel instrumentation tape recording system, operating at Seismic Array Station for th e last two decades, are also discussed. (author). 7 figs

35

Periodic solutions for second order Hamiltonian systems  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper we present some recent multiplicity results for a class of second order Hamiltonian systems. Exploiting the variational structure of the problem, it will be shown how the existence of multiple, even infinitely many, periodic solutions can be assured.

Giuseppina D'Aguì

2011-06-01

36

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)

37

Fundamental research. Mendeleev's periodical classification: heavy elements received their definitive identity  

International Nuclear Information System (INIS)

The International Union of Pure and Applied Chemistry (IUPAC) has definitively adopted the names of the heavy elements with mass ranges of 101 to 109 during its general assembly of August 1997. The newly defined names are given. Short note. (J.S.)

38

Resonant periodic orbits in the exoplanetary systems  

CERN Document Server

The planetary dynamics of $4/3$, $3/2$, $5/2$, $3/1$ and $4/1$ mean motion resonances is studied by using the model of the general three body problem in a rotating frame and by determining families of periodic orbits for each resonance. Both planar and spatial cases are examined. In the spatial problem families of periodic orbits are obtained after analytical continuation of vertical critical orbits. The linear stability of orbits is also examined. Concerning initial conditions nearby stable periodic orbits, we obtain long-term planetary stability, while unstable orbits are associated with chaotic evolution that destabilizes the planetary system. Stable periodic orbits are of particular importance in planetary dynamics, since they can host real planetary systems. We found stable orbits up to $60^\\circ$ of mutual planetary inclination, but in most families the stability does not exceed $20^\\circ$-$30^\\circ$, depending on the planetary mass ratio. Most of these orbits are very eccentric. Stable inclined circula...

Antoniadou, K I

2013-01-01

39

Recent Mapping and Sampling on Chukchi Borderland and the Alpha/Mendeleev Ridge Complex  

Science.gov (United States)

Since 2003, four cruises on the icebreaker USCG HEALY have collected high-resolution multibeam sonar mapping data in the Amerasia Basin in support of a potential submission by the U.S. for an extended continental shelf as defined under the United Nations Convention on Law of the Sea Article 76. The latest of these cruises (HEALY0805), completed in early Sept.of 2008, extended this mapping to the southern portions of the Alpha/Mendeleev Ridge complex, and supplemented the mapping with seven dredge stations, providing rare, direct sampling of both regions. While sparse in comparison to complete-coverage multibeam sonar surveys (due to the difficulties associated with operating in ice-covered waters), the new multibeam sonar data still provide an unprecedented new view of the tectonic, sedimentary, glacial and fluid- flow related processes in the Arctic Ocean. The Chukchi Borderland is characterized by shallow plateaus that often show evidence of interaction with icebergs and glaciers (scours and grooves) at depths as great as 900 m, as well as the presence of numerous gas/fluid expulsion features (pockmarks and acoustic wipe-out zones). The topographic highs associated with the Borderland are often bounded by very steep scarps including the eastern edge of Northwind Ridge (the Northwind Escarpment) which is a 600 km long NNE trending feature with an average slope of 10-15 degrees. Similar steep-sided ridges, separated by deep linear valleys also appear in mapped areas of the Alpha/Mendeleev Ridge complex. Some of these features have slopes as great at 60 degrees and thus are excellent targets for dredging. Our dredging of these slopes has returned a wide array of volcanic and sedimentary rock types, many of which appear to be representative of outcrops (rather than ice rafted material). A preliminary shipboard examination of these samples (they were just collected this morning - 3 September 2008 - a few days before the abstract is due) shows them to include mudstone, sandstone, shale, breccia, along with volcanic and metamorphic rocks lending support to the earlier evidence for the continental origin of the Chukchi Borderland. Dredges from the topographic highs of the southern part of Alpha/Mendeleev Ridge complex returned indurated sediment with defined sedimentary structures that appear to be non-marine in origin; further descriptions of the nature of these rocks and speculation about their implications for the origin of the features from which they were dredged will require more detailed laboratory analyses which will be carried out in the coming months.

Mayer, L. A.; Brumley, K.; Andronikov, A.; Chayes, D. N.; Armstrong, A. A.; Calder, B.; Hall, J. K.; Clyde, W. C.; Bothner, W. A.; Gardner, J. V.

2008-12-01

40

Effective imaging systems based on periodic lattices  

Energy Technology Data Exchange (ETDEWEB)

A crucial question in imaging problems from diffracted wavefields is the evaluation of the information content of data and the related reconstruction performance in terms of spatial resolution. It is well-known that full-view tomographic reconstructions are characterized by resolution limits of the order of one half propagated wavelength. These limits are further deteriorated when a truncated measurement domain is exploited for the imaging. In this Letter, we show that when the imaging system comprises a periodic layer located between a linear array of probes and the investigated domain, the resolution limits are substantially improved compared to the case of a homogenous scenario. This intriguing result is a consequence of the multiscattering effects arising from the periodicity of the structure. The study provides physical insight supported by mathematical arguments paving the way to the development of effective imaging systems requiring few radiating elements.

Gennarelli, Gianluca, E-mail: gennarelli.g@irea.cnr.it; Soldovieri, Francesco [Institute for Electromagnetic Sensing of the Environment, National Research Council of Italy, Via Diocleziano 328, 80124 Napoli (Italy); Persico, Raffaele [Institute for Archaeological and Monumental Heritage, National Research Council of Italy, Via Monteroni, Campus Universitario, 73100 Lecce (Italy)

2014-05-12

 
 
 
 
41

Periodic Solutions for Highly Nonlinear Oscillation Systems  

DEFF Research Database (Denmark)

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 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.

Ghadimi, M; Barari, Amin

2012-01-01

42

Low Power Long Period Magnetotelluric System  

Science.gov (United States)

We have constructed a new MT system for periods longer than 1 second that uses substantially less power and is considerably easier to deploy than predecessors, such as the Geological Survey of Canada [GSC] Long Period Intelligent Magnetotelluric System [LIMS]. Technical aspects of these new systems include: Fully watertight; light weight [5 kg w/o magnetometer head], Eurocard card cage, 1.7 watt power consumption - 140mA @ 12vdc, built-in solar panel charge controller, GPS-disciplined timekeeping accurate to 1ms, 24-bit 8 Hz Analog to Digital conversion, data storage on a PCMCIA flash disk [85M and up], magnetic field: +/- 80,000 nT range with 10pT resolution, electric field ch: +/- 200 mv with sub-microvolt useful resolution. A setup program automatically handles most deployment tasks including recording site location and data start time. Data are logged in files that begin at hour marks and are of one-hour duration. They are thus automatically synchronous at an array of instruments. Data retrieval consists of moving a PCMCIA card from the data logger to a laptop computer. A revision of this system is already in progress. It will feature PC104 card formats and will be lighter, smaller and have even lower power consumption. Ten of these systems were deployed for the first time during August and September 2001, in Argentina. Sample data from these deployments will be shown.

Narod, B. B.; Bennest, J. R.; Booker, J. R.

2001-12-01

43

Periodic orbits in analytically perturbed Poisson systems  

Science.gov (United States)

Analytical perturbations of a family of finite-dimensional Poisson systems are considered. It is shown that the family is analytically orbitally conjugate in U?Rn to a planar harmonic oscillator defined on the symplectic leaves. As a consequence, the perturbed vector field can be transformed in the domain U to the Lagrange standard form. On the latter, use can be made of averaging theory up to second order to study the existence, number and bifurcation phenomena of periodic orbits. Examples are given ranging from harmonic oscillators with a potential and Duffing oscillators, to a kind of zero-Hopf singularity analytic normal form.

García, Isaac A.; Hernández-Bermejo, Benito

2014-05-01

44

Quantum Monte Carlo Study on periodic systems  

Science.gov (United States)

Quantum Monte Carlo (QMC) calculations, using the variational (VMC) and diffusion (DMC) methods is performed on periodic systems. We report calculations of the cohesive energy, the occupied bandwidth and the pair correlation functions (PCFs)on the body-centered cubic solid sodium. DMC calculations including the core polarization potential (CPP) give an excellent value for the cohesive energy of the solid. The calculated bandwidth 3.7 eV is significantly larger than the experimental value of 2.6 eV, but is in good agreement with a recent many body caluculation with a sophisticated approximation. We also report very recent results on NiO.

Maezono, Ryo; Towler, Mike; Needs, Richard

2004-03-01

45

First Recovery of Submarine Basalts from the Chukchi Borderland and Alpha / Mendeleev Ridge, Arctic Ocean  

Science.gov (United States)

In addition to multibeam bathymetric mapping of the Amerasia Basin in the high Arctic Ocean, the August- September 2008 cruise of USCGC Icebreaker HEALY (HLY0805) conducted a total of seven dredging profiles along the southern sectors of the Alpha/Mendeleev Ridge and in the northernmost region of Northwind Ridge of Chukchi Borderland. Five of the seven dredges were recovered on relatively gentle slopes (30-40°) and yielded mostly mud with a small number of fragments of sedimentary rocks and ice rafted debris (IRD), which indicates either rapid sedimentation rates on the bathymetrically high features sampled or lack of recently active volcanism on these features. Two dredges taken from steep escarpments with slopes (> 55°) at >3.5 km depth recovered some of the first known submarine basaltic samples from the Arctic Ocean floor away from the Gakkel Ridge. Ragged, freshly exposed edges indicate that these samples were broken from outcrop rather than being IRD. In some cases (e.g., a rise on the ocean floor between the Alpha/Mendeleev Ridge and Northwind Ridge) the samples have well-preserved pillow-basalt structures with fresh glassy rims up to 4 cm thick. Inward from the rims, the rocks are dark-grey lavas, some with visible plagioclase laths and rare phenocrysts up to 0.5 mm in length, some with visible signs of alteration such as local occurrence of chlorite. Surfaces that were exposed to water can be covered with a thin black film of Mn oxides. Occurrence of this volcanism away from any obvious spreading centers compels us to hypothesize that forthcoming geochemical analyses are likely to identify these rocks as the first Arctic Ocean floor samples to exhibit ocean island basalt compositions. The dredge taken from the northern slope of Northwind Ridge, along slopes as steep as > 45°, recovered a variety of rock types including sedimentary and basaltic rocks. Some of the basalts have columnar jointing (the size of the columns is only up to 5-6 cm across, suggesting fairly thin lava flows). These samples have a strongly altered glassy matrix with abundant plagioclase phenocrysts (up to 3 mm in length). Thin chilled basaltic crust on the lava surfaces displays pahoehoe structures, suggesting subaerial eruptions. Presence of subaerial basalts in this area supports the notion that the Chukchi Borderland has a continental origin. It is possible that further mapping using multibeam bathymetric methods and geochemical studies will show the high Arctic to possess a large igneous province built on both continental and oceanic crust.

Andronikov, A.; Mukasa, S.; Mayer, L. A.; Brumley, K.

2008-12-01

46

Aberrational description of periodical time-of-flight optical systems  

Energy Technology Data Exchange (ETDEWEB)

There are many examples where the aberrational approach does not work very well for long periodical CPO systems. This paper considers some typical tasks where the aberrational approach can be used effectively also for periodical systems.

Berdnikov, A.S., E-mail: asberd@yandex.ru [Institute of Analytical Instrumentation, Rizhskij pr. 26, 190103 St. Petersburg (Russian Federation)

2011-07-21

47

Alguns aspectos históricos da classificação periódica dos elementos químicos Some historical aspects of the periodic classification of the chemical elements  

Directory of Open Access Journals (Sweden)

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

1997-02-01

48

Periodic Table of the Elements in the Perspective of Artificial Neural Networks  

Science.gov (United States)

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…

Lemes, Mauricio R.; Dal Pino, Arnaldo

2011-01-01

49

Periodicity  

Science.gov (United States)

In thinking about a title for this chapter, the word periodicity came to mind. I was sure this had some kind of pop culture reference. After discussing this with my wife, we figured I was thinking of synchronicity, which is a reference to music by the band, The Police. Looking the word Periodicity up on the internet, I found that I was, in fact, a science geek and had not made a hip reference. Periodicity refers mainly to the Periodic Table, which is a focus of this chapter. No music, just science.

Robertson, William C.

2007-01-01

50

Magnetization in short-period mesoscopic electron systems  

CERN Document Server

We calculate the magnetization of the two-dimensional electron gas in a short-period lateral superlattice, with the Coulomb interaction included in Hartree and Hartree-Fock approximations. We compare the results for a finite, mesoscopic system modulated by a periodic potential, with the results for the infinite periodic system. In addition to the expected strong exchange effects, the size of the system, the type and the strength of the lateral modulation leave their fingerprints on the magnetization.

Gudmundsson, V; Manolescu, A; Gudmundsson, Vidar; Erlingsson, Sigurdur I.; Manolescu, Andrei

1999-01-01

51

Time periodic traveling wave solutions for periodic advection-reaction-diffusion systems  

Science.gov (United States)

We study the existence, uniqueness, and asymptotic stability of time periodic traveling wave solutions to a class of periodic advection-reaction-diffusion systems. 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 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* are asymptotically stable in certain sense. In addition, we establish the nonexistence of time periodic traveling waves with speed c>c*.

Zhao, Guangyu; Ruan, Shigui

2014-08-01

52

Implicit numerical integration for periodic solutions of autonomous nonlinear systems  

Science.gov (United States)

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.

Thurston, G. A.

1982-01-01

53

Periodic integrable systems with delta-potentials  

CERN Document Server

In this paper we study root system generalizations of the quantum Bose-gas on the circle with pair-wise delta function interactions. The underlying symmetry structures are shown to be governed by the associated graded of Cherednik's (suitably filtered) degenerate double affine Hecke algebra, acting by Dunkl-type differential-reflection operators. We use Gutkin's generalization of the equivalence between the impenetrable Bose-gas and the free Fermi-gas to derive the Bethe ansatz equations and the Bethe ansatz eigenfunctions.

Emsiz, E; Stokman, J V; Emsiz, Erdal; Opdam, Eric M.; Stokman, Jasper V.

2005-01-01

54

Hemipelagic deposits on the Mendeleev and northwestern Alpha submarine Ridges in the Arctic Ocean:acoustic stratigraphy, depositional environment and an inter-ridge correlation calibrated by the ACEX results  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The first high resolution multichannel seismic data from the Mendeleev and Alpha Ridges in the Arctic Ocean have been used to investigate the depositional history, and compare acoustic stratigraphies of the three main sub-marine ridges (Mendeleev, Alpha and Lomonosov) in the polar ocean. Acoustic basement on the Mendeleev Ridge is covered by a ~0.6–0.8 s thick sediment drape over highs and up to 1.8 s within grabens. A pronounced angular discordance at 0.18–0.23 s below the seafloor along...

Bruvoll, Vibeke; Kristoffersen, Yngve; Coakley, Bernard J.; Hopper, John R.

2010-01-01

55

Manifold structures of unstable periodic orbits and the appearance of periodic windows in chaotic systems  

Science.gov (United States)

Manifold structures of the Lorenz system, the Hénon map, and the Kuramoto-Sivashinsky system are investigated in terms of unstable periodic orbits embedded in the attractors. Especially, changes of manifold structures are focused on when some parameters are varied. The angle between a stable manifold and an unstable manifold (manifold angle) at every sample point along an unstable periodic orbit is measured using the covariant Lyapunov vectors. It is found that the angle characterizes the parameter at which the periodic window corresponding to the unstable periodic orbit finishes, that is, a saddle-node bifurcation point. In particular, when the minimum value of the manifold angle along an unstable periodic orbit at a parameter is small (large), the corresponding periodic window exists near (away from) the parameter. It is concluded that the window sequence in a parameter space can be predicted from the manifold angles of unstable periodic orbits at some parameter. The fact is important because the local information in a parameter space characterizes the global information in it. This approach helps us find periodic windows including very small ones.

Kobayashi, Miki U.; Saiki, Yoshitaka

2014-02-01

56

Systematic Computer Assisted Proofs of periodic orbits of Hamiltonian systems  

Science.gov (United States)

The numerical study of Dynamical Systems leads to obtain invariant objects of the systems such as periodic orbits, invariant tori, attractors and so on, that helps to the global understanding of the problem. In this paper we focus on the rigorous computation of periodic orbits and their distribution on the phase space, which configures the so called skeleton of the system. We use Computer Assisted Proof techniques to make a rigorous proof of the existence and the stability of families of periodic orbits in two-degrees of freedom Hamiltonian systems, which provide rigorous skeletons of periodic orbits. To that goal we show how to prove the existence and stability of a huge set of discrete initial conditions of periodic orbits, and later, how to prove the existence and stability of continuous families of periodic orbits. We illustrate the approach with two paradigmatic problems: the Hénon-Heiles Hamiltonian and the Diamagnetic Kepler problem.

Barrio, Roberto; Rodríguez, Marcos

2014-08-01

57

Effective Hamiltonian approach to periodically perturbed quantum optical systems  

International Nuclear Information System (INIS)

We apply the method of Lie-type transformations to Floquet Hamiltonians for periodically perturbed quantum systems. Some typical examples of driven quantum systems are considered in the framework of this approach and corresponding effective time dependent Hamiltonians are found

58

Fredholm operators, evolution semigroups, and periodic solutions of nonlinear periodic systems  

Science.gov (United States)

Let X be a Banach space and L the generator of the evolution semigroup associated with the ?-periodic evolutionary process {U(t,s)}t?s on the space P?(X) of all ?-periodic continuous X-valued functions. We give criteria for the existence of periodic solutions to nonlinear systems of the form Lp=-?F(p,?) under the condition that 1 is a normal eigenvalue of the monodromy operator U(?,0). The proof is based on a new decomposition of the space P?(X) by constructing a right inverse of L.

Miyazaki, Rinko; Kim, Dohan; Naito, Toshiki; Shin, Jong Son

2014-12-01

59

Optimum time between periodic test and maintenance for redundant systems  

International Nuclear Information System (INIS)

A model for analysis of the optimum time between periodic test and maintenance for redundant systems is provided. Conditions when this optimum time exists are analyzed. The optimum time is based on safety considerations, maintenance and repair costs, or total operating costs. Time between periodic test and maintenance is of great significance for safety and cost of operation of redundant systems. If the time between periodic test and maintenance is too large, then deterioration of the equipment may reduce safety and increase economic risk due to potential forced outages. If the period of time between periodic test and maintenance is too short, then safety will be reduced again because of the increase of unavailability due to frequent scheduled outages. Operating costs will also increase. In this paper the mathematical model for optimizing the time between periodic test and maintenance from the standpoint of safety and operational costs is developed

60

Periodic solutions of nonautonomous differential systems modeling obesity population  

Energy Technology Data Exchange (ETDEWEB)

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.

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

 
 
 
 
61

Periodic orbits of Hamiltonian systems: Applications to perturbed Kepler problems  

International Nuclear Information System (INIS)

We provide for a class of Hamiltonian systems in the action–angle variables sufficient conditions for showing the existence of periodic orbits. We expand this result to the study of the existence of periodic orbits of perturbed spatial Keplerian Hamiltonians with axial symmetry. Finally, we apply these general results for finding periodic orbits of the Matese–Whitman Hamiltonian, of the spatial anisotropic Hamiltonian and of the spatial generalized van der Waals Hamiltonian

62

Quasi-Periodic and Periodic Solutions for Systems of Coupled Nonlinear Schrödinger Equations  

CERN Document Server

We consider travelling periodic and quasiperiodic wave solutions of a set of coupled nonlinear Schrödimger equations. In fibre optics these equations can be used to model single mode fibers with strong birefringence and two-mode optical fibres. Recently these equations appear as modes, which describe pulse-pulse interaction in wavelength-division-multiplexed channels of optical fiber transmission systems. Two phase quasi-periodic solutions for integrable Manakov system are given in tems of two-dimensional Kleinian functions. The reduction of quasi-periodic solutions to elliptic functions is dicussed. New solutions in terms of generalized Hermite polynomilas, which are associated with two-gap Treibich-Verdier potentials are found.

Christiansen, P L; Enolskii, V Z; Kostov, N A

1999-01-01

63

The periodic system of chemical elements: old and new developments  

International Nuclear Information System (INIS)

Some historical facts about the construction of a periodic system of chemical elements are reviewed. The Madelung rule is used to generate an unusual format for the periodic table. Following the work of Byakov, Kulakov, Rumer and Fet, such a format is further refined on the basis of a chain of groups starting with SU(2)xS0(4.2)

64

Nontrivial periodic solutions of asymptotically linear Hamiltonian systems  

Directory of Open Access Journals (Sweden)

Full Text Available We study the existence of periodic solutions for some asymptotically linear Hamiltonian systems. By using the Saddle Point Theorem and Conley index theory, we obtain new results under asymptotically linear conditions.

Guihua Fei

2001-11-01

65

Nontrivial periodic solutions of asymptotically linear Hamiltonian systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We study the existence of periodic solutions for some asymptotically linear Hamiltonian systems. By using the Saddle Point Theorem and Conley index theory, we obtain new results under asymptotically linear conditions.

Guihua Fei

2001-01-01

66

Problem of unusual valent states of f-elements in relation to D.I. Mendeleev periodical law  

International Nuclear Information System (INIS)

A question of participation of inner 6p-atomic orbitals in the formation of chemical bond and expansion of valency possibilities of actinides at the expense of it is discussed. The forecasting of new valency forms for actinides puts a question of their possible similarity with lantanides. It is shown that the similarity is of a ''cross'' character, and it is explained by cymbate change of excitation energy from fsup(n) to fsup(n-1)d-electron states. In the first half of lanthanides 4f-electron levels are more stable than in the second one, whereas in actinides in the first half 5f-levels are less stable than in the second one. Such similarity will be manifested in all properties, which are conditioned by partial participation in the formation of bonds of d-atomic orbitals. In the limiting case of ion configurations of fsup(n) tetrade effect should be manifested, which is conditioned by the fact that quantum numbers of complete orbital momentum are symmetric as to electron configurations of f3(f10) and f4(f11). It will be manifested in all the properties, which are determined by the diffusion of f-orbitals

67

Mechanism of extraction 4th period of periodic system metal ions with carboxylic acids in sulphate systems  

International Nuclear Information System (INIS)

Extraction of transition metal ions of the 4th period of Periodic system by carboxylic acids in sulfate systems was studied. It is shown that depending on composition and physicochemical properties of aqueous phase (pH, the type of metal ion, its complexing properties etc.) the solvent extraction may proceed according to two mechanisms: cation-exchange or hydration-solvation. The extraction is more effective in the field of cation-exchange mechanism

68

Periodic solutions of second-order nonautonomous dynamical systems  

Directory of Open Access Journals (Sweden)

Full Text Available We study the existence of periodic solutions for second-order nonautonomous dynamical systems. We give four sets of hypotheses which guarantee the existence of solutions. We were able to weaken the hypotheses considerably from those used previously for such systems. We employ a new saddle point theorem using linking methods.

Martin Schechter

2006-08-01

69

Periodic solutions of second-order nonautonomous dynamical systems  

Directory of Open Access Journals (Sweden)

Full Text Available We study the existence of periodic solutions for second-order nonautonomous dynamical systems. We give four sets of hypotheses which guarantee the existence of solutions. We were able to weaken the hypotheses considerably from those used previously for such systems. We employ a new saddle point theorem using linking methods.

Schechter Martin

2006-01-01

70

On the complete ionization of a periodically perturbed quantum system  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We analyze the time evolution of a one-dimensional quantum system with zero range potential under time periodic parametric perturbation of arbitrary strength and frequency. We show that the projection of the wave function on the bound state vanishes, i.e. the system gets fully ionized, as time grows indefinitely.

Costin, O.; Lebowitz, J. L.; Rokhlenko, A.

2000-01-01

71

Gastrointestinal system obstructuions in neonatal period-I  

Directory of Open Access Journals (Sweden)

Full Text Available The suspect of gasrointestinal system obstructions rises in the prenatal period and confirmation and diagnosis are made postnatally. Thorough questioning of gestational period of a pregnant mother gives some clues in terms of gastrointestinal system obstructions. Anamnesis indicating the presence of a congenital defect in the family or relatives would lead to more careful examination of the child. Polyhydramniosis is an indication requiring special attention almost everytime. Five to ten percent of the infants born from the mother with polyhydramniosis have gastrointestinal system obstructions. Inspection and physical exam,following the birth (in the postnatal period is sufficient in diagnosis and even planning the treatment for the 90% of the patients. (Turk Arch Ped 2010; 45 Suppl: 35-7

Ergun Erdo?an

2010-05-01

72

Characterization of a periodically driven chaotic dynamical system  

CERN Document Server

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.

Crisanti, A; Lacorata, G; Purini, R; Crisanti, A

1996-01-01

73

Analysis and synthesis of synchronous periodic and chaotic systems  

International Nuclear Information System (INIS)

Chaotic systems are known for their sensitivity to initial conditions. However, Pecora and Carroll [Phys. Rev. Lett. 64, 821 (1990); Phys. Rev. A 44, 2374 (1991); IEEE Trans. Circuits Syst. 38, 453 (1991)] have recently shown that a system, consisting of two Lorenz oscillators exhibiting chaos, could achieve synchronization if a portion of the second system is driven by the first. In this paper, a necessary and sufficient condition for synchronization is presented. This condition has been used to create a high-dimensional chaotic system with a nonlinear subsystem. This system shows synchronization both when it exhibits periodic limit cycles and when it turns chaotic

74

Analysis and synthesis of synchronous periodic and chaotic systems  

Science.gov (United States)

Chaotic systems are known for their sensitivity to initial conditions. However, Pecora and Carroll [Phys. Rev. Lett. 64, 821 (1990); Phys. Rev. A 44, 2374 (1991); IEEE Trans. Circuits Syst. 38, 453 (1991)] have recently shown that a system, consisting of two Lorenz oscillators exhibiting chaos, could achieve synchronization if a portion of the second system is driven by the first. In this paper, a necessary and sufficient condition for synchronization is presented. This condition has been used to create a high-dimensional chaotic system with a nonlinear subsystem. This system shows synchronization both when it exhibits periodic limit cycles and when it turns chaotic.

He, Rong; Vaidya, P. G.

1992-12-01

75

Long period seismic ground motions for isolation systems  

International Nuclear Information System (INIS)

In this paper numerical simulations of long period strong ground motions are calculated based on theoretical seismological models of the seismic source and wave propagation. The method includes both near-field and far-field terms and surface waves as well as body waves which allows valid simulations at both short and large distances. Long period ground motions for magnitude 6.75 and magnitude 8.0 events are computed at distances of 3 to 30 km. The resulting response spectral displacements are compared to the SEAOC 1990 spectrum for base-isolated system. At a period of 2 seconds, the SEAOC spectrum is close to the spectrum for a magnitude 8.0 earthquake. However, at a period of 5 seconds, the SEAOC spectrum is much larger than the simulated notions even for a magnitude 8 event

76

Many-body energy localization transition in periodically driven systems  

International Nuclear Information System (INIS)

According to the second law of thermodynamics the total entropy of a system is increased during almost any dynamical process. The positivity of the specific heat implies that the entropy increase is associated with heating. This is generally true both at the single particle level, like in the Fermi acceleration mechanism of charged particles reflected by magnetic mirrors, and for complex systems in everyday devices. Notable exceptions are known in noninteracting systems of particles moving in periodic potentials. Here the phenomenon of dynamical localization can prevent heating beyond certain threshold. The dynamical localization is known to occur both at classical (Fermi–Ulam model) and at quantum levels (kicked rotor). However, it was believed that driven ergodic systems will always heat without bound. Here, on the contrary, we report strong evidence of dynamical localization transition in both classical and quantum periodically driven ergodic systems in the thermodynamic limit. This phenomenon is reminiscent of many-body localization in energy space. -- Highlights: •A dynamical localization transition in periodically driven ergodic systems is found. •This phenomenon is reminiscent of many-body localization in energy space. •Our results are valid for classical and quantum systems in the thermodynamic limit. •At critical frequency, the short time expansion for the evolution operator breaks down. •The transition is associated to a divergent time scale

77

Periodic inspection for safety of CANDU heat transport piping systems  

International Nuclear Information System (INIS)

Periodic inspection of heat transport and emergency core cooling piping systems is intended to maintain an adequate level of safety throughout the life of the plant, and to protect plant personnel and the public from the consequences of a failure and release of fission products. This report outlines a rational approach to the periodic inspection based on a fully probabilistic model. It demonstrates the methodology based on theoretical treatment and experimental data whereby the strength of a pressurized pipe or vessel containing a defect could be evaluated. It also shows how the extension of the defect at various lifetimes could be predicted. These relationships are prerequisite for the probabilistic formulation and analysis for the periodic inspection of piping systems

78

Electrostatics of solvated systems in periodic boundary conditions  

CERN Document Server

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)]. A comprehensive discussion of real-space 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-dimensional and two-dimen...

Andreussi, Oliviero

2014-01-01

79

Periodic solutions of a spring-pendulum system.  

Science.gov (United States)

A study has been made of a dynamical system composed of a pendulum and a harmonic oscillator, in order to show the remarkable resemblance with many classical celestial mechanics problems, in particular, the restricted three-body problem. It is shown that the well-known investigations of periodic orbits can be applied to the present dynamics problem.

Broucke, R.; Baxa, P. A.

1973-01-01

80

Periodic solutions for some second order Hamiltonian systems  

International Nuclear Information System (INIS)

We use the saddle point theorem of Benci–Rabinowitz to study the existence of periodic solutions with a fixed energy for second order Hamiltonian conservative systems without any symmetry; the key difficulty of the proof is proving the Palais–Smale condition and the non-constant property for the minimax critical point

 
 
 
 
81

Periodic orbits for an infinite family of classical superintegrable systems  

International Nuclear Information System (INIS)

We show that all bounded trajectories in the two-dimensional classical system with the potential V(r,?)=?2r2+(?k2)/(r2cos2k?)+(?k2)/(r2sin2k?) are closed for all integer and rational values of k. The period is T=?/2? and does not depend on k. This agrees with our earlier conjecture suggesting that the quantum version of this system is superintegrable.

82

Synchronization of chaotic systems with on–off periodic coupling  

International Nuclear Information System (INIS)

In this paper, we study the complete synchronization between two chaotic systems with on–off periodic coupling. Using the stability theory and the comparison theorem of differential equations, we derive less restrictive synchronization conditions than those resulting from the Lyapunov theory. The theoretical results show that two chaotic systems can achieve complete synchronization if the time-average coupling strength is large enough. Finally, numerical simulations fully verify the effectiveness of the analytical results. (paper)

83

The period ratio distribution of Kepler's candidate multiplanet systems  

CERN Document Server

We calculate and analyze the distribution of period ratios observed in systems of Kepler exoplanet candidates including studies of both adjacent planet pairs and all planet pairs. These distributions account for both the geometrical bias against detecting more distant planets and the effects of incompleteness due to planets missed by the data reduction pipeline. In addition to some of the known features near first-order mean-motion resonances (MMR), there is a significant excess of planet pairs with period ratios near 2.2. The statistical significance of this feature is assessed using Monte Carlo simulation. We also investigate the distribution of period ratios near first-order MMR and compare different quantities used to measure this distribution. We find that beyond period ratios of ~2.5, the distribution of all period ratios follows a power-law with an exponent -1.26 +/- 0.05. We discuss implications that these results may have on the formation and dynamical evolution of Kepler-like planetary systems---sys...

Steffen, Jason H

2014-01-01

84

Phase jitter in periodically dispersion-managed optical transmission systems  

Science.gov (United States)

We investigate the phase jitter in long-haul optical transmission systems with periodic dispersion management and amplification. We compare different dispersion-managed soliton systems and a conventional soliton system having the same pulse width and path-averaged dispersion. Using the variational method, we derive the ordinary differential equations for the pulse parameters perturbed by amplifier noise and hence calculate the phase jitter. We verify the analytical results by numerically solving the nonlinear Schrödinger equation using split-step Fourier algorithm. The results suggest that the reduction of nonlinear phase noise in dispersion-managed soliton systems is possible compared to a conventional soliton system. It is also revealed that the phase noise is enhanced in stronger dispersion-managed systems. We also explore the phase noise effect in dispersion-managed quasi-linear systems and find that phase jitter is mitigated in highly dispersive fibers.

Faisal, Mohammad; Maruta, Akihiro

2009-05-01

85

Projective synchronization of a hyperchaotic system via periodically intermittent control  

International Nuclear Information System (INIS)

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

86

Monodromy factorization for periodic Lie systems and reconstruction phases  

Science.gov (United States)

From a factorization formula for the monodromy element of a periodic Lie system on a Lie group, we show that the concepts geometric and dynamical phases are naturally defined for such class of systems. An interpretation of the phases is given in terms of the Poisson geometry and the Hamiltonian dynamics induced by the coadjoint action on the Lie coalgebra of the group. Applying these results we give a general formulae for the reconstruction dynamics of a system with symmetry which generalize previous results given by Marsden et al. in [1].

Flores-Espinoza, R.

2008-11-01

87

Binary systems: implications for outflows & periodicities relevant to masers  

CERN Document Server

Bipolar molecular outflows have been observed and studied extensively in the past, but some recent observations of periodic variations in maser intensity pose new challenges. Even quasi-periodic maser flares have been observed and reported in the literature. Motivated by these data, we have tried to study situations in binary systems with specific attention to the two observed features, i.e., the bipolar flows and the variabilities in the maser intensity. We have studied the evolution of spherically symmetric wind from one of the bodies in the binary system, in the plane of the binary. Our approach includes the analytical study of rotating flows with numerical computation of streamlines of fluid particles using PLUTO code. We present the results of our findings assuming simple configurations, and discuss the implications.

Singh, Nishant K

2012-01-01

88

Effect of Guard Period Insertion in MIMO OFDM System  

Directory of Open Access Journals (Sweden)

Full Text Available Orthogonal frequency-division multiplexing (OFDM is the technique of choice in the digital broad-band applications, which divides a channel with a higher relative data rate into several orthogonal sub-channels with a lower data rate. This very special feature of OFDM technique attracts the new generation of communication, which in mobile communication terminology called as “4th generation technology”. This paper is an approach towards very important aspect/ performance parameter of OFDM. First we will talk about the key role of Guard Period insertion in OFDM system in optimize Inter-Symbol Interference (ISI. Secondly, how the different method/way of adding guard period effect the OFDM system performance is also discussed & elaborated with help of MATLAB simulated results.

Mitalee Agrawal,

2011-09-01

89

A family of Nikishin systems with periodic recurrence coefficients  

CERN Document Server

Suppose we have a Nikishin system of $p$ measures with the $k$th generating measure of the Nikishin system supported on an interval $\\Delta_k\\subset\\er$ with $\\Delta_k\\cap\\Delta_{k+1}=\\emptyset$ for all $k$. It is well known that the corresponding staircase sequence of multiple orthogonal polynomials satisfies a $(p+2)$-term recurrence relation whose recurrence coefficients, under appropriate assumptions on the generating measures, have periodic limits of period $p$. (The limit values depend only on the positions of the intervals $\\Delta_k$.) Taking these periodic limit values as the coefficients of a new $(p+2)$-term recurrence relation, we construct a canonical sequence of monic polynomials $\\{P_{n}\\}_{n=0}^{\\infty}$, the so-called \\emph{Chebyshev-Nikishin polynomials}. We show that the polynomials $P_{n}$ themselves form a sequence of multiple orthogonal polynomials with respect to some Nikishin system of measures, with the $k$th generating measure being absolutely continuous on $\\Delta_{k}$. In this way w...

Delvaux, Steven; Lagomasino, Guillermo López

2011-01-01

90

Vibration isolation of automotive vehicle engine using periodic mounting systems  

Science.gov (United States)

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 mounting systems with plain and periodic mounts will be studied first. The dynamic characteristics of such systems will be obtained experimentally in both cases. The tests will be then carried out to study the performance characteristics of periodic mounts with geometrical and/or material periodicity. The effectiveness of the periodicity on the vibration levels of mounting systems will be demonstrated theoretically and experimentally. Finally, the experimental results will be compared with the theoretical predictions.

Asiri, S.

2005-05-01

91

Periodic orbits for an infinite family of classical superintegrable systems  

Energy Technology Data Exchange (ETDEWEB)

We show that all bounded trajectories in the two-dimensional classical system with the potential V(r,{phi})={omega}{sup 2}r{sup 2}+({alpha}k{sup 2})/(r{sup 2}cos{sup 2}k{phi})+({beta}k{sup 2})/(r{sup 2}sin{sup 2}k{phi}) are closed for all integer and rational values of k. The period is T={pi}/2{omega} and does not depend on k. This agrees with our earlier conjecture suggesting that the quantum version of this system is superintegrable.

Tremblay, Frederick; Winternitz, Pavel [Centre de recherches mathematiques and Departement de mathematiques et de statistique, Universite de Montreal, C.P. 6128, Succ. Centre-Ville, Montreal (QC) H3C 3J7 (Canada); Turbiner, Alexander V [Instituto de Ciencias Nucleares, UNAM, A.P. 70-543, 04510 (Mexico)], E-mail: tremblaf@crm.umontreal.ca, E-mail: wintern@crm.umontreal.ca, E-mail: turbiner@nucleares.unam.mx

2010-01-08

92

Applying Adjacent Hyperbolas to Calculation of the Upper Limit of the Periodic Table of Elements, with Use of Rhodium  

Directory of Open Access Journals (Sweden)

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.

Khazan A.

2011-01-01

93

Alguns aspectos históricos da classificação periódica dos elementos químicos / Some historical aspects of the periodic classification of the chemical elements  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese [...] Abstract in english 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 prope [...] r periodic classification are also presented.

Mario, Tolentino; Romeu C., Rocha-Filho; Aécio Pereira, Chagas.

94

Alguns aspectos históricos da classificação periódica dos elementos químicos / Some historical aspects of the periodic classification of the chemical elements  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese [...] Abstract in english 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 prope [...] r periodic classification are also presented.

Mario, Tolentino; Romeu C., Rocha-Filho; Aécio Pereira, Chagas.

1997-02-01

95

Averaging of time-periodic systems without a small parameter  

CERN Document Server

In this article, we present a new approach to averaging in non-Hamiltonian systems with periodic forcing. The results here do not depend on the existence of a small parameter. In fact, we show that our averaging method fits into an appropriate nonlinear equivalence problem, and that this problem can be solved formally by using the Lie transform framework to linearize it. According to this approach, we derive formal coordinate transformations associated with both first-order and higher-order averaging, which result in more manageable formulae than the classical ones. Using these transformations, it is possible to correct the solution of an averaged system by recovering the oscillatory components of the original non-averaged system. In this framework, the inverse transformations are also defined explicitly by formal series; they allow the estimation of appropriate initial data for each higher-order averaged system, respecting the equivalence relation. Finally, we show how these methods can be used for identifyi...

Chekroun, Mickaël D; Roux, Jean; Varadi, Ferenc

2010-01-01

96

Determination of the Period of Binary Asteroid Systems  

Science.gov (United States)

In the study of asteroids, binary pairs offer a unique window of study. By observing these systems and determining the period of the secondary, it is possible to determine system mass (e.g. Pravec and Hahn 1997; Ryan et al., 2004). With mass and volume, properties such as bulk density and porosity can be derived. At the University of Central Florida we have begun a binary asteroid hunt, in conjunction with the Prague consortium, in order to identify new binary candidates and to better constrain data on known pairs. All of the observations are collected on campus using a 0.5meter f/8.1 Ritchey-Chretien telescope with a SBIG STL-6303E detector. For our first test target we observed the known binary asteroid 107 Camila over a period of six days for approximately six to eight hours a night. The data is then processed using an open source python algorithm developed by Nate Lust. The data is read in, reduced, and compared to a standard star. Once the light curve was generated we make use of the CLEAN algorithm, originally developed by Hogbom (1974), to extract meaningful periods from the light curve.

Lust, Nathaniel B.; Britt, D. T.

2008-09-01

97

Periodic dynamic systems for infected hosts and mosquitoes  

Directory of Open Access Journals (Sweden)

Full Text Available A mathematical model for the purpose of analysing the dynamic of the populations of infected hosts anf infected mosquitoes when the populations of mosquitoes are periodic in time is here presented. By the computation of a parameter lambda (the spectral radius of a certain monodromy matrix one can state that either the infection peters out naturally (lambda 1 the infection becomes endemic. The model generalizes previous models for malaria by considering the case of periodic coefficients; it is also a variation of that for gonorrhea. The main motivation for the consideration of this present model was the recent studies on mosquitoes at an experimental rice irrigation system, in the South-Eastern region of Brazil.

Oliva W. M.

1996-01-01

98

A family of Nikishin systems with periodic recurrence coefficients  

Energy Technology Data Exchange (ETDEWEB)

Suppose we have a Nikishin system of p measures with the kth generating measure of the Nikishin system supported on an interval {Delta}{sub k} subset of R with {Delta}{sub k} Intersection {Delta}{sub k+1} = Empty-Set for all k. It is well known that the corresponding staircase sequence of multiple orthogonal polynomials satisfies a (p+2)-term recurrence relation whose recurrence coefficients, under appropriate assumptions on the generating measures, have periodic limits of period p. (The limit values depend only on the positions of the intervals {Delta}{sub k}.) Taking these periodic limit values as the coefficients of a new (p+2)-term recurrence relation, we construct a canonical sequence of monic polynomials {l_brace}P{sub n}{r_brace}{sub n=0}{sup {infinity}}, the so-called Chebyshev-Nikishin polynomials. We show that the polynomials P{sub n} themselves form a sequence of multiple orthogonal polynomials with respect to some Nikishin system of measures, with the kth generating measure being absolutely continuous on {Delta}{sub k}. In this way we generalize a result of the third author and Rocha [22] for the case p=2. The proof uses the connection with block Toeplitz matrices, and with a certain Riemann surface of genus zero. We also obtain strong asymptotics and an exact Widom-type formula for functions of the second kind of the Nikishin system for {l_brace}P{sub n}{r_brace}{sub n=0}{sup {infinity}}. Bibliography: 27 titles.

Delvaux, Steven; Lopez, Abey; Lopez, Guillermo L

2013-01-31

99

On solving the master equation in spatially periodic systems  

Science.gov (United States)

We present a new method for solving the master equation for a system evolving on a spatially periodic network of states. The network contains 2? images of a ``unit cell'' of n states, arranged along one direction with periodic boundary conditions at the ends. We analyze the structure of the symmetrized (2?n) × (2?n) rate constant matrix for this system and derive a recursive scheme for determining its eigenvalues and eigenvectors, and therefore analytically expressing the time-dependent probabilities of all states in the network, based on diagonalizations of n × n matrices formed by consideration of a single unit cell. We apply our new method to the problem of low-temperature, low-occupancy diffusion of xenon in the zeolite silicalite-1 using the states, interstate transitions, and transition state theory-based rate constants previously derived by June et al. [J. Phys. Chem. 95, 8866 (1991)]. The new method yields a diffusion tensor for this system which differs by less than 3% from the values derived previously via kinetic Monte Carlo (KMC) simulations and confirmed by new KMC simulations conducted in the present work. The computational requirements of the new method are compared against those of KMC, numerical solution of the master equation by the Euler method, and direct molecular dynamics. In the problem of diffusion of xenon in silicalite-1, the new method is shown to be faster than these alternative methods by factors of about 3.177 × 104, 4.237 × 103, and 1.75 × 107, respectively. The computational savings and ease of setting up calculations afforded by the new method of master equation solution by recursive reduction of dimensionality in diagonalizing the rate constant matrix make it attractive as a means of predicting long-time dynamical phenomena in spatially periodic systems from atomic-level information.

Kolokathis, Panagiotis D.; Theodorou, Doros N.

2012-07-01

100

Embedding of Analytic Quasi-Periodic Cocycles into Analytic Quasi-Periodic Linear Systems and its Applications  

Science.gov (United States)

In this paper, we prove that any analytic quasi-periodic cocycle close to constant is the Poincaré map of an analytic quasi-periodic linear system close to constant, which bridges both methods and results in quasi-periodic linear systems and cocycles. We also show that the almost reducibility of an analytic quasi-periodic linear system is equivalent to the almost reducibility of its corresponding Poincaré cocycle. By the local embedding theorem and the equivalence, we transfer the recent local almost reducibility results of quasi-periodic linear systems (Hou and You, in Invent Math 190:209-260, 2012) to quasi-periodic cocycles, and the global reducibility results of quasi-periodic cocycles (Avila, in Almost reducibility and absolute continuity, 2010; Avila et al., in Geom Funct Anal 21:1001-1019, 2011) to quasi-periodic linear systems. Finally, we give a positive answer to a question of Avila et al. (Geom Funct Anal 21:1001-1019, 2011) and use it to study point spectrum of long-range quasi-periodic operator with Liouvillean frequency. The embedding also holds for some nonlinear systems.

You, Jiangong; Zhou, Qi

2013-11-01

 
 
 
 
101

ECONOMIC AND FINANCIAL PERIODS INDUCED THROUGH BANKING SYSTEM  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract:This paper is an empirical study which analyzes the influence of banking system to the economic and financial environment. At the basis of this research there are two subjective definitions of economic instability periods (CII and of financial instability periods (FII and two composite indexes called EWI (Economic Warning Index and FWI (Financial Warning Index defined in a prior research. Because it is not possible to predict the exact point in time at which the crisis sets in, the purpose of this paper is to identify possible vulnerabilities induced through banking system and to treat them in order to mitigate the costs of the economy. I defined a set of eighteen potential leading indicators from banking/financial sector, in the period 2000 - 2012. The countries included in the study are Czech Republic, Hungary and Romania. It was composed a balance panel with seven hundred and eighty observations. There is both a quantitative and qualitative approach. Using econometrics technicques as OLS regressions, Fixed effects and Fixed dummy effects there were identfied significant banking indicators in explaining economic and financial instability periods. Then, I compose a banking index which captures the costs occurred to the banking system and I assess its performance in explaining the economic and financial instability indexes through in the sample and out of the sample techniques. At the basis of my decision to choose a continuous model was the fact that it motivates policy makers in steering policy continuously and the fact that there is no need to decide between yes/ no value of crisis. This research aim to observe the influence of the banking sector evolution to the incidence of economic and financial instability periods and give us a warning regardless any negative trends in the macroeconomic or financial activity, affecting the national or the global situation. Using model simulations on historical data, the model performance was assessed upon in the sample and out of sample estimation techniques. The evaluation results suggest that banking indicators give us a warning signal of the negative trend of economic and financial environment.

Ionita Rodica -Oana

2013-07-01

102

Coulomb disorder in periodic systems: Effect of unscreened charged impurities  

International Nuclear Information System (INIS)

We study the effect of unscreened charged impurities on periodic systems. We show that the long-wavelength component of the disorder becomes long ranged and dominates static correlation functions. On the other hand, because of the statistical tilt symmetry, dynamical properties such as pinning remain unaffected. As a concrete example, we focus on the effect of Coulombian disorder generated by charged impurities on three-dimensional charge density waves with nonlocal elasticity. We calculate the x-ray intensity and find that it is identical to the one produced by thermal fluctuations in a disorder-free smectic-A phase. We discuss the consequences of these results for experiments

103

Periodic Solutions of Singular Hamiltonian Systems with Fixed Energies  

CERN Document Server

We use the variational minimizing method with a suitable constraint and a variant of the famous Benci-Rabinowitz's saddle point Theorem to study the existence of new non-trival periodic solutions with a prescribed energy for second order Hamiltonian systems with singular potentials $V\\in C^2(R^n\\backslash O,R)$ and $V\\in C^1(R^n\\backslash O,R)$ which may have an unbounded potential well, our results can be regarded as some complementaries of the well-known Theorems of Benci-Gluck-Ziller-Hayashi and Ambrosetti-Coti Zelati etc..

Hua, Qingqing

2011-01-01

104

Quantum revivals in periodically driven systems close to nonlinear resonances  

International Nuclear Information System (INIS)

We calculate the quantum revival time for a wave packet initially well localized in a one-dimensional potential in the presence of an external periodic modulating field. The dependence of the revival time on various parameters of the driven system is shown analytically. As an example of an application of our approach, we compare the analytically obtained values of the revival time for various modulation strengths with the numerically computed ones in the case of a driven gravitational cavity. We show that they are in very good agreement

105

Periodic orbits of hybrid systems and parameter estimation via AD  

International Nuclear Information System (INIS)

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 between two given periodic orbits which is then minimized using a trust-region minimization algorithm (DS83) to find optimal fits of the model to a reference orbit (Cas04). There are two different yet related goals that motivate the algorithmic choices listed above. The first is to provide a simple yet powerful framework for studying periodic motions in mechanical systems. Formulating mechanically correct equations of motion for systems of interconnected rigid bodies, while straightforward, is a time-consuming error prone process. Much of this difficulty stems from computing the acceleration of each rigid body in an inertial reference frame. The acceleration is computed most easily in a redundant set of coordinates giving the spatial positions of each body: since the acceleration is just the second derivative of these positions. Rather than providing explicit formulas for these derivatives, automatic differentiation can be employed to compute these quantities efficiently during the course of a simulation. The feasibility of these ideas was investigated by applying these techniques to the problem of locating stable walking motions for a disc-foot passive walking machine (CGMR01, Gar99, McG91). The second goal for this work was to investigate the application of smooth optimization methods to periodic orbit parameter estimation problems in neural oscillations. Others (BB93, FUS93, VB99) have favored non-continuous optimization methods such as genetic algorithms, stochastic search methods, simulated annealing and brute-force random searches because of their perceived suitability to the landscape of typical objective functions in parameter space, particularly for multi-compartmental neural models. Here we argue that a carefully formulated optimization problem is amenable to Newton-like methods and has a sufficiently smooth landscape in parameter space that these methods can be an efficient and effective alternative. The plan of this paper is as follows. In Section 1 we provide a definition of hybrid systems that is the basis for modeling systems with discontinuities or discrete transitions. Sections 2, 3, and 4 briefly describe the Taylor series integration, periodic orbit tracking, and parameter estimation algorithms. For full treatments of these algorithms, we refer the reader to (Phi03, Cas04, CPG04). The software implementation of these algorithms is briefly described in Section 5 with particular emphasis on the automatic differentiation software ADMC++. Finally, these algorithms are applied to the bipedal walking and Hodgkin-Huxley based neural oscillation problems discussed above in Section 6.

106

Singular Continuous Floquet Operator for Periodic Quantum Systems  

CERN Document Server

Consider the Floquet operator of a time independent quantum system, acting on a separable Hilbert space, periodically perturbed by a rank one kick: $e^{-iH_0T}e^{-i\\kappa T |\\phi\\ket\\bra\\phi|}$ where $T$, $\\kappa$ are respectively the period and the coupling constant and $H_0$ is a pure point self-adjoint operator, bounded from below. Under some hypotheses on the vector $\\phi$, cyclic for $H_0$ we prove the following: If the gaps between the eigenvalues $(\\lambda_n)$ are such that: $\\lambda_{n+1}-\\lambda_{n}\\geq C n^{-\\gamma}$ for some $\\gamma \\in ]0,1[$ and $C>0$, then the Floquet operator of the perturbed system is purely singular continuous T-a.e. If $H_0$ is the Hamiltonian of the one-dimensional rotator on $L^2({\\mathbb R}/T_0{\\mathbb Z})$ and the ratio $2\\pi T/T_0^2$ is irrational, then the Floquet operator is purely singular continuous as soon as $\\kappa T \

Bourget, O

2004-01-01

107

The Shortest Period Detached Binary White Dwarf System  

CERN Document Server

We identify SDSS J010657.39-100003.3 (hereafter J0106-1000) as the shortest period detached binary white dwarf (WD) system currently known. We targeted J0106-1000 as part of our radial velocity program to search for companions around known extremely low-mass (ELM, ~ 0.2 Msol) WDs using the 6.5m MMT. We detect peak-to-peak radial velocity variations of 740 km/s with an orbital period of 39.1 min. The mass function and optical photometry rule out a main-sequence star companion. Follow-up high-speed photometric observations obtained at the McDonald 2.1m telescope reveal ellipsoidal variations from the distorted primary but no eclipses. This is the first example of a tidally distorted WD. Modeling the lightcurve, we constrain the inclination angle of the system to be 67 +- 13 deg. J0106-1000 contains a pair of WDs (0.17 Msol primary + 0.43 Msol invisible secondary) at a separation of 0.32 Rsol. The two WDs will merge in 37 Myr and most likely form a core He-burning single subdwarf star. J0106-1000 is the shortest...

Kilic, Mukremin; Kenyon, S J; Prieto, Carlos Allende; Andrews, J; Kleinman, S J; Winget, K I; Winget, D E; Hermes, J J

2011-01-01

108

Wide aperture periodic lens system for multiple Compton backscattering  

CERN Document Server

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.

Miyahara, Y

2002-01-01

109

Optimal stabilization of unstable periodic orbits embedded in chaotic systems  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish En este artículo se propone un enfoque basado en el flujo gradiente con el propósito de estabilizar órbitas periódicas inestables inmersas en sistemas caóticos. Tal enfoque considera al problema de estabilización como un problema de control óptimo, lo cual permite obtener una solución en línea al pr [...] oblema de interés, para lo cual se introduce el cálculo de las sensibilidades de los estados con respecto a la entrada de control. El controlador por retroalimentación resultante permite estabilizar órbitas periódicas inestables inmersas en ambas clases de sistemas caoticos, con o sin número de Floquet impar. Además, el enfoque propuesto se extiende para identificar el periodo de la órbita periódica inestable a ser estabilizada, en el caso en que este sea desconocido. Se realizan experimentos de simulación del controlador propuesto, para estabilizar orbitas periódicas inestables de los sistemas de Rössler y de Lorenz. Abstract in english A gradient-flow-based approach is proposed in this paper for stabilizing unstable periodic orbits (UPO) embedded in chaotic systems. In order to obtain an on-line stabilizing solution, the stabilization problem is considered to be an optimal control problem, and system state sensitivities with respe [...] ct to the control input are introduced. The resulting feedback controller is able to stabilize UPO embedded in both kind of systems, with or without an odd Floquet number. Moreover, the proposed approach is easily extended to identifying the period of the UPO to be stabilized when it is unknown. Simulation experiments of the proposed controller are carried out on the Rössler and the Lorenz systems.

C.A., Cruz-Villar.

2007-10-01

110

Optimal stabilization of unstable periodic orbits embedded in chaotic systems  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish En este artículo se propone un enfoque basado en el flujo gradiente con el propósito de estabilizar órbitas periódicas inestables inmersas en sistemas caóticos. Tal enfoque considera al problema de estabilización como un problema de control óptimo, lo cual permite obtener una solución en línea al pr [...] oblema de interés, para lo cual se introduce el cálculo de las sensibilidades de los estados con respecto a la entrada de control. El controlador por retroalimentación resultante permite estabilizar órbitas periódicas inestables inmersas en ambas clases de sistemas caoticos, con o sin número de Floquet impar. Además, el enfoque propuesto se extiende para identificar el periodo de la órbita periódica inestable a ser estabilizada, en el caso en que este sea desconocido. Se realizan experimentos de simulación del controlador propuesto, para estabilizar orbitas periódicas inestables de los sistemas de Rössler y de Lorenz. Abstract in english A gradient-flow-based approach is proposed in this paper for stabilizing unstable periodic orbits (UPO) embedded in chaotic systems. In order to obtain an on-line stabilizing solution, the stabilization problem is considered to be an optimal control problem, and system state sensitivities with respe [...] ct to the control input are introduced. The resulting feedback controller is able to stabilize UPO embedded in both kind of systems, with or without an odd Floquet number. Moreover, the proposed approach is easily extended to identifying the period of the UPO to be stabilized when it is unknown. Simulation experiments of the proposed controller are carried out on the Rössler and the Lorenz systems.

C.A., Cruz-Villar.

111

Period and period change measurements for 143 SuperWASP eclipsing binary candidates near the short-period limit and discovery of a doubly eclipsing quadruple system  

CERN Document Server

Building on previous work, a new search of the SuperWASP archive was carried out to identify eclipsing binary systems near the short-period limit. 143 candidate objects were detected with orbital periods between 16000 and 20000 s, of which 97 are new discoveries. Period changes significant at 1 sigma or more were detected in 74 of these objects, and in 38 the changes were significant at 3 sigma or more. The significant period changes observed followed an approximately normal distribution with a half-width at half-maximum of ~0.1 s/yr. There was no apparent relationship between period length and magnitude or direction of period change. Amongst several interesting individual objects studied, 1SWASP J093010.78+533859.5 is presented as a new doubly eclipsing quadruple system, consisting of a contact binary with a 19674.575 s period and an Algol-type binary with a 112799.109 s period, separated by 66.1 AU, being the sixth known system of this type.

Lohr, M E; Kolb, U C; Maxted, P F L; Todd, I; West, R G

2012-01-01

112

Periodic inspection optimization model for a complex repairable system  

International Nuclear Information System (INIS)

This paper proposes a model to find the optimal periodic inspection interval on a finite time horizon for a complex repairable system. In general, it may be assumed that components of the system are subject to soft or hard failures, with minimal repairs. Hard failures are either self-announcing or the system stops when they take place and they are fixed instantaneously. Soft failures are unrevealed and can be detected only at scheduled inspections but they do not stop the system from functioning. In this paper we consider a simple policy where soft failures are detected and fixed only at planned inspections, but not at moments of hard failures. One version of the model takes into account the elapsed times from soft failures to their detection. The other version of the model considers a threshold for the total number of soft failures. A combined model is also proposed to incorporate both threshold and elapsed times. A recursive procedure is developed to calculate probabilities of failures in every interval, and expected downtimes. Numerical examples of calculation of optimal inspection frequencies are given. The data used in the examples are adapted from a hospital's maintenance data for a general infusion pump.

113

On the stability of periodically time-dependent quantum systems  

CERN Document Server

The main motivation of this article is to derive sufficient conditions for dynamical stability of periodically driven quantum systems described by a Hamiltonian H(t), i.e., conditions under which it holds sup_{t in R} | (psi(t),H(t) psi(t)) |<\\infty where psi(t) denotes a trajectory at time t of the quantum system under consideration. We start from an analysis of the domain of the quasi-energy operator. Next we show, under certain assumptions, that if the spectrum of the monodromy operator U(T,0) is pure point then there exists a dense subspace of initial conditions for which the mean value of energy is uniformly bounded in the course of time. Further we show that if the propagator admits a differentiable Floquet decomposition then || H(t) psi(t) || is bounded in time for any initial condition psi(0), and one employs the quantum KAM algorithm to prove the existence of this type of decomposition for a fairly large class of H(t). In addition, we derive bounds uniform in time on transition probabilities betwe...

Duclos, Pierre; Stovicek, Pavel; Vittot, Michel

2007-01-01

114

18 CFR 301.4 - Exchange Period Average System Cost determination.  

Science.gov (United States)

...2010-04-01 false Exchange Period Average System Cost determination. 301.4 Section...POWER MARKETING ADMINISTRATIONS AVERAGE SYSTEM COST METHODOLOGY FOR SALES FROM UTILITIES... § 301.4 Exchange Period Average System Cost determination. (a)...

2010-04-01

115

The Higgs Boson in the Periodic System of Elementary Particles  

Directory of Open Access Journals (Sweden)

Full Text Available It is proposed that the observed Higgs Boson at the LHC is the Standard Model Higgs boson that adopts the existence of the hidden lepton condensate. The hidden lepton is in the forbidden lepton family, outside of the three lepton families of the Standard Model. Being forbidden, a single hidden lepton cannot exist alone; so it must exist in the lepton condensate as a composite of ?’ and ?’± hidden leptons and their corresponding antileptons. The calculated average mass of the hidden lepton condensate is 128.8 GeV in good agreements with the observed 125 or 126 GeV. The masses of the hidden lepton condensate and all elementary particles including leptons, quarks, and gauge bosons are derived from the periodic system of elementary particles. The calculated constituent masses are in good agreement with the observed values by using only four known constants: the number of the extra spatial dimensions in the eleven-dimensional membrane, the mass of electron, the mass of Z boson, and the fine structure constant.

Ding-Yu Chung

2013-04-01

116

XIX Mendeleev Congress on general and applied chemistry. Four-volumes book. Abstracts. Volume 2. Chemistry and technology of materials, including nanomaterials  

International Nuclear Information System (INIS)

The abstracts of the XIX Mendeleev Congress on general and applied chemistry held 25-30 September 2011 in Volgograd are presented. The program includes the Congress plenary and section reports, poster presentations, symposia and round tables on key areas of chemical science and technology, and chemical education. The work of the Congress was held the following sections: 1. Fundamental problems of chemical sciences; 2. Chemistry and technology of materials, including nanomaterials; 3. Physicochemical basis of metallurgical processes; 4. Current issues of chemical production, technical risk assessment; 5. Chemical aspects of modern power and alternative energy sources; 6. Chemistry of fossil and renewable hydrocarbons; 7. Analytical chemistry: new methods and instruments for chemical research and analysis; 8. Chemical education. Volume 2 includes abstracts of oral and poster presentations of the section Chemistry and technology of materials, including nanomaterials, and author index

117

ORBITAL SYSTEM OF DISTRIBUTION OF ELECTRONS IN ATOM AND STRUCTURE OF PERIODIC SYSTEM OF ELEMENTS ??????????? ??????? ????????????? ?????????? ? ????? ? ????????? ????????????? ??????? ?????????  

Directory of Open Access Journals (Sweden)

Full Text Available In the article, for the first time we have considered group of electrons radial to atomic nucleus with equal value of orbital quantum number and equal sequence of emergence on subshells. As a result of this consideration, the exclusion orbital principle which regulates distribution of electrons in atom on values of spin has been established. On the basis of this principle, the orbital system of distribution of electrons which adequately corresponds to the valid system installed according to the spectral analysis is developed. From positions of orbital system the new explanation of reasons for deviation of the valid system of distribution of electrons in atom from ideal system of consecutive filling of electron shells has been offered and the nature of the empirical rule is opened. The structure of periodic system is also considered and the explanation of the reasons pair repetition of the periods on number of elements is offered. It is thus shown that borders of the chemical periods are displaced relatively borders of the periods of orbital system on two elements to the left

Vyatkin V. B.

2013-05-01

118

Quantum diffusion in semi-infinite periodic and quasiperiodic systems  

International Nuclear Information System (INIS)

This paper studies quantum diffusion in semi-infinite one-dimensional periodic lattice and quasiperiodic Fibonacci lattice. It finds that the quantum diffusion in the semi-infinite periodic lattice shows the same properties as that for the infinite periodic lattice. Different behaviour is found for the semi-infinite Fibonacci lattice. In this case, there are still C(t) ? t?? and d(t) ? t?. However, it finds that 0 < ? < 1 for smaller time, and ? = 0 for larger time due to the influence of surface localized states. Moreover, ? for the semi-infinite Fibonacci lattice is much smaller than that for the infinite Fibonacci lattice. Effects of disorder on the quantum diffusion are also discussed

119

Loschmidt echo and dynamical fidelity in periodically driven quantum systems  

Science.gov (United States)

We study the dynamical fidelity F(t) and the Loschmidt echo L(t) , following a periodic driving of the transverse magnetic field of a quantum Ising chain (back and forth across the quantum critical point) by calculating the overlap between the initial ground state and the state reached after n periods ?. We show that [log{ F}(n\\tau)]/L (the logarithm of the fidelity per site) reaches a steady value in the asymptotic limit n \\to \\infty , and we derive an exact analytical expression for this quantity. Remarkably, the steady-state value of [log{ F}(n\\tau\\to \\infty)]/L shows memory of non-trivial phase information which is instead hidden in the case of thermodynamic quantities; this conclusion, moreover, is not restricted to 1-dimensional models.

Sharma, Shraddha; Russomanno, Angelo; Santoro, Giuseppe E.; Dutta, Amit

2014-06-01

120

Kirkwood Gaps and stability of conservative periodic systems  

International Nuclear Information System (INIS)

Kirkwood (Smithsonian Inst. A. Rep. (1868)) demonstrated that there were gaps in the distribution of asteroids at certain distances from the Sun which occurred at positions where the orbital periods of the asteroids were in simple ratio to the period of Jupiter. It has also been shown that at some ratios closer to Jupiter groups of asteroids occur. Examples of this distribution are the 2/1 resonance called the Hecube Gap and the 3/2 resonance called the Hilda Group. In an attempt to explain this distribution the stability of the orbits has been examined using a theory of stability represented by Hill's equation (Acta. Math.; 8:1 (1886)). In the theoretical work here reported it has been shown that the equation has stable solutions for Hilda-type asteroids and unstable solutions for the Hecuba-type which the author feels accounts for the striking differences in the two types of resonance. (U.K.)

 
 
 
 
121

40 CFR 75.24 - Out-of-control periods and adjustment for system bias.  

Science.gov (United States)

...Out-of-control periods and adjustment for system bias. 75.24 Section 75.24 Protection...Out-of-control periods and adjustment for system bias. (a) If an out-of-control period...A and B of this part. (d) When the bias test indicates that an SO2...

2010-07-01

122

Periodic solutions of systems with asymptotically even nonlinearities  

Directory of Open Access Journals (Sweden)

Full Text Available New conditions of solvability based on a general theorem on the calculation of the index at infinity for vector fields that have degenerate principal linear part as well as degenerate ?next order? terms are obtained for the 2?-periodic problem for the scalar equation x?+n2x=g(|x|+f(t,x+b(t with bounded g(u and f(t,x?0 as |x|?0. The result is also applied to the solvability of a two-point boundary value problem and to resonant problems for equations arising in control theory.

Peter E. Kloeden

2000-01-01

123

Feedback control in a general almost periodic discrete system of plankton allelopathy.  

Science.gov (United States)

We study the properties of almost periodic solutions for a general discrete system of plankton allelopathy with feedback controls and establish a theorem on the uniformly asymptotic stability of almost periodic solutions. PMID:24592189

Yin, Wenshuang

2014-01-01

124

Chaotic component obscured by strong periodicity in voice production system  

Science.gov (United States)

The effect of glottal aerodynamics in producing the nonlinear characteristics of voice is investigated by comparing the outputs of the asymmetric composite model and the two-mass model. The two-mass model assumes the glottal airflow to be laminar, nonviscous, and incompressible. In this model, when the asymmetric factor is decreased from 0.65 to 0.35, only 1:1 and 1:2 modes are detectable. However, with the same parameters, four vibratory modes (1:1, 1:2, 2:4, 2:6) are found in the asymmetric composite model using the Navier-Stokes equations to describe the complex aerodynamics in the glottis. Moreover, the amplitude of the waveform is modulated by a small-amplitude noiselike series. The nonlinear detection method reveals that this noiselike modulation is not random, but rather it is deterministic chaos. This result agrees with the phenomenon often seen in voice, in which the voice signal is strongly periodic but modulated by a small-amplitude chaotic component. The only difference between the two-mass model and the composite model is in their descriptions of glottal airflow. Therefore, the complex aerodynamic characteristics of glottal airflow could be important in generating the nonlinear dynamic behavior of voice production, including bifurcation and a small-amplitude chaotic component obscured by strong periodicity. PMID:18643315

Tao, Chao; Jiang, Jack J.

2010-01-01

125

Almost periodic solutions of distributed parameter biochemical systems with time delay and time varying input  

Directory of Open Access Journals (Sweden)

Full Text Available In this article we study the existence of almost periodic solutions for distributed parameters biochemical system, with time delay when the input $S_{m in}$ is time dependent. This study is motivated by the input begin time dependent in many applications, and by the importance of almost periodically varying environments. Using the semigroup method, we prove that if the input is almost periodic then the system has an almost periodic solution.

Abdou K. Drame

2013-07-01

126

Finite size effects in the magnetization of periodic mesoscopic systems  

CERN Document Server

We calculate the orbital magnetization of a confined 2DEG as a function of the number of electrons in the system. Size effects are investigated by systematically increasing the area of the confining region. The results for the finite system are compared to an infinite one, where the magnetization is calculated in the thermodynamic limit. In all calculations the electron-electron interaction is included in the Hartree approximation.

Erlingsson, S I; Gudmundsson, V; Erlingsson, Sigurdur I.; Manolescu, Andrei; Gudmundsson, Vidar

1999-01-01

127

Mobility induces global synchronization of oscillators in periodic extended systems  

International Nuclear Information System (INIS)

We study the synchronization of locally coupled noisy phase oscillators that move diffusively in a one-dimensional ring. Together with the disordered and the globally synchronized states, the system also exhibits wave-like states displaying local order. We use a statistical description valid for a large number of oscillators to show that for any finite system there is a critical mobility above which all wave-like solutions become unstable. Through Langevin simulations, we show that the transition to global synchronization is mediated by a shift in the relative size of attractor basins associated with wave-like states. Mobility disrupts these states and paves the way for the system to attain global synchronization.

128

Mobility induces global synchronization of oscillators in periodic extended systems  

CERN Document Server

We study synchronization of locally coupled noisy phase oscillators which move diffusively in a one-dimensional ring. Together with the disordered and the globally synchronized states, the system also exhibits several wave-like states which display local order. We use a statistical description valid for a large number of oscillators to show that for any finite system there is a critical spatial diffusion above which all wave-like solutions become unstable. Through Langevin simulations, we show that the transition to global synchronization is mediated by the relative size of attractor basins associated to wave-like states. Spatial diffusion disrupts these states and paves the way for the system to attain global synchronization.

Peruani, Fernando; Morelli, Luis G

2010-01-01

129

A nonlinear system under combined periodic and random excitation  

International Nuclear Information System (INIS)

The anharmonic oscillator under combined sinusoidal and white noise excitation is studied using the Gaussian closure approximation. The mean response and the steady-state variance of the system is obtained by the WKBJ approximation and also by the Fokker-Planck equation. The multiple steady-state solutions are obtained and their stability analysis is presented. Numeric al results are obtained for a particular set of system parameters. The theoretical results are compared with a digital simulation study to bring out the usefulness of the present approximate theory

130

Graphics Expression System Reading Center, Evaluation Period 1975-76.  

Science.gov (United States)

This paper describes the Graphics Expression System Reading Center Program, which provided students with limited learning motivation and with below norm achievement in reading, as well as those students reading on and above grade level with the opportunity to use the compact recording studio equipment in the production of television shows. The…

Hopkins, Thomas F.

131

Short-period noncontact close binary systems. III - RU Eridani  

Science.gov (United States)

The close binary system RU Eri is studied on the basis of spectroscopic observations. Its spectral type is classified to be F3-4 IV-V and its orbital elements are deduced to be K1 = 109 km s-1, f(M) = 0.0853 M_sun;, and a1 sin i = 1.36 R_sun;. With the spectroscopic mass ratio q = 0.55 determined in the present work, the light curves of Sarma and Sanwal (1981; AAA 29.119.024) are analyzed with Yamasaki's (1981; AAA 29.117.041) synthesis method. The system is found to consist of a slightly evolved F3-4 primary and an early K secondary. Both components almost fill their critical Roche lobes but are still inside of them.

Nakamura, Y.; Yamasaki, A.; Kitamura, M.

132

The European debate on rate systems in the interwar period  

International Nuclear Information System (INIS)

This article describes a particular branch that evolved in the diffusion of electrical rate systems in twentieth-century Europe and the debate that ensued between the competitive, promotional and cost based approaches. Three major questions are addressed: What factors and historical circumstances favoured the emergence of more or less efficient pricing schemes? Why did some enterprises opt for promotional rates while others defended the cost based alternative? What is the historical origin of marginal cost pricing? It is shown how the volatility of the costs that characterize hydro-electric production made this particular technology very sensitive to a cost approach towards pricing and to a seasonal and time-of-day perspective on rate systems.

133

The European debate on rate systems in the interwar period  

Energy Technology Data Exchange (ETDEWEB)

This article describes a particular branch that evolved in the diffusion of electrical rate systems in twentieth-century Europe and the debate that ensued between the competitive, promotional and cost based approaches. Three major questions are addressed: What factors and historical circumstances favoured the emergence of more or less efficient pricing schemes? Why did some enterprises opt for promotional rates while others defended the cost based alternative? What is the historical origin of marginal cost pricing? It is shown how the volatility of the costs that characterize hydro-electric production made this particular technology very sensitive to a cost approach towards pricing and to a seasonal and time-of-day perspective on rate systems. (author)

Madureira, Nuno Luis [ISCTE cacifo 321B, Av Forcas Armadas, 1600 Lisboa (Portugal)

2010-08-15

134

The Kondo effect in periodic narrow-band systems  

CERN Document Server

The Kondo divergences owing to interaction of current carriers with local moments in highly correlated electron systems are considered within the Hubbard and s-d exchange models with infinitely strong on-site interaction. The picture of density of states contaning a peak at the Fermi level is obtained. Various forms of the self-consistent approximation are used. Smearing of the peak owing to spin dynamics and finite temperatures is investigated.

Irkhin, V Yu

1999-01-01

135

Generalized method of optimization of maintenance periodicity of NPP safety systems  

International Nuclear Information System (INIS)

The method of optimization of maintenance periodicity of the equipment taking into account factors of its reliability and repair quality is submitted. The unavailability factor is used as a criterion of optimization of maintenance periodicity. Basing on the submitted method the small computer code is developed. This code allows to calculate reliability factors of a separate safety system and to determine optimum maintenance periodicity of its equipment. Optimization of maintenance periodicity of a complex of safety systems is stipulated also. As an example results of optimization of maintenance periodicity at Zaporizhzhya NPP are presented

136

The direct approach to gravitation and electrostatics method for periodic systems  

DEFF Research Database (Denmark)

The direct approach to gravitation and electrostatics (DAGE) algorithm is an accurate, efficient, and flexible method for calculating electrostatic potentials. In this paper, we show that the algorithm can be easily extended to consider systems with many different kinds of periodicities, such as crystal lattices, surfaces, or wires. The accuracy and performance are nearly the same for periodic and aperiodic systems. The electrostatic potential for semiperiodic systems, namely defects in crystal lattices, can be obtained by combining periodic and aperiodic calculations. The method has been applied to an ionic model system mimicking NaCl, and to a corresponding covalent model system.

Losilla, Sergio Alberto; Sundholm, D

2010-01-01

137

18 CFR 301.4 - Exchange Period Average System Cost determination.  

Science.gov (United States)

... Exchange Period Average System Cost determination. 301.4 Section...or reduction in Contract System Cost associated with the acquisition...territory. (iii) A forecast of capital and operating cost increases or reductions...

2010-04-01

138

A phase-lock-loop-based control system for suppressing periodic vibration in smart structural systems  

Science.gov (United States)

This paper presents a simple, effective and economical system capable of suppressing periodic vibration (external or self-induced) affecting a structure or payload. The approach used integrates piezoelectric materials/actuators, sensors and low-cost electronics in a novel way. The key innovation is the use of phase-lock loops (PLLs) and switch-capacitor filters (SCFs) for the on-line identification, tracking and control of periodic vibration. This method concentrates its control action at those frequencies where periodic vibration is detected. Among the advantages of this approach are the following: it is conceptually simple, easily expandable and modular; the controller does not rely on a model of the structure and it only needs some approximate notion of the frequency range where the periodic disturbances are expected to occur; it is robust and can be operated at high gain without loss of stability; it is not significantly affected by the presence of random vibration or sensor noise and it can be implemented with inexpensive electronics. The effectiveness of this new approach was experimentally evaluated using a test unit consisting of a simple structure, accelerometers and Terfenol-D actuators. The structure was excited by driving one of the actuators with sinusoidal and random signals. The resulting periodic disturbances were measured using the accelerometers. The acceleration signals were passed though a bank of PLLs and associated SCFs to detect the fundamental frequency and harmonics. This information was used to drive another actuator that rejected the original disturbances, and attenuation levels as high as 30 dB were achieved.

Algrain, Marcelo; Hardt, Steve; Ehlers, Douglas

1997-02-01

139

The virial theorem and exact properties of density functionals for periodic systems  

CERN Document Server

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.

Mirhosseini, H; Baldsiefen, T; Sanna, A; Proetto, C R; Gross, E K U

2014-01-01

140

Virial theorem and exact properties of density functionals for periodic systems  

Science.gov (United States)

In the framework of density functional theory, scaling and the virial theorem are essential tools for deriving the 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.

Mirhosseini, H.; Cangi, A.; Baldsiefen, T.; Sanna, A.; Proetto, C. R.; Gross, E. K. U.

2014-06-01

 
 
 
 
141

The orbital periods of three sdB eclipsing binary systems  

Science.gov (United States)

Recent timings of eclipses made between 2011 and 2014 are presented for three binary systems with hot subdwarf primary stars, AA Dor, NY Vir and EC 10246-2707. In the case of AA Dor, the period remains constant. In NY Vir, a rapidly pulsating sdBVr with a cool companion, the period change now appears more complex than can be described by a simple quadratic. EC 10246-2707, which has previously appeared to have a constant period, now appears to be showing a significant period increase. The effect of gravitational radiation in HW Vir-like systems is briefly discussed.

Kilkenny, D.

2014-12-01

142

Bifurcation of periodic orbits emanated from a vertex in discontinuous planar systems  

Science.gov (United States)

We discuss bifurcation of periodic orbits in discontinuous planar systems with discontinuities on finitely many straight lines intersecting at the origin and the unperturbed system has either a limit cycle or an annulus of periodic orbits. Assume that the unperturbed periodic orbits cross every switching line transversally exactly once. For the first case we give a condition for the persistence of the limit cycle. For the second case, we obtain the expression of the first order Melnikov function and establish sufficient conditions on the number of limit cycles bifurcate from the periodic annulus. Then we generalize our results to systems with discontinuities on finitely many smooth curves. As an application, we present a piecewise cubic system with 4 switching lines and show that the maximum number of limit cycles bifurcate from the periodic annulus can be affected by the position of the switching lines.

Hu, Nan; Du, Zhengdong

2013-12-01

143

Controlling chaos in low and high dimensional systems with periodic parametric perturbations  

Energy Technology Data Exchange (ETDEWEB)

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.

Mirus, K.A.; Sprott, J.C.

1998-06-01

144

Controlling chaos in low and high dimensional systems with periodic parametric perturbations  

International Nuclear Information System (INIS)

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

145

Stabilization of Periodic Solutions in a Thedered Satellite System by Damping Injection  

DEFF Research Database (Denmark)

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 equation and the region of stable periodic solutions in the parameter plane is found.

Larsen, Martin Birkelund; Blanke, Mogens

2009-01-01

146

H-infinity Control of Linear Systems with Almost Periodic Inputs  

DEFF Research Database (Denmark)

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, includeproblems with periodic disturbance signals and periodic referencesignals, where some components of these vector-valued signals areknown a priori.

Larsen, Mikael

1996-01-01

147

Chaotic attractor in a periodically forced two-phase flow system  

International Nuclear Information System (INIS)

y frequencies; however, at many other frequencies it cannot. The trajectories that do remain in bounded regions of phase space can be, depending on the forcing frequency, periodic with a short or very long period, very near periodic, or completely aperiodic or chaotic. Hence, it is possible to enhance heat transfer while maintaining safety in two-phase flow systems by operating them in an oscillatory mode

148

Existence and Stability Periodic Solution for Prey-Predator System with Functional Response  

Directory of Open Access Journals (Sweden)

Full Text Available The existence and stability of periodic solution in Prey-Predator system with diffusion, time-delay and Holing type ? are invertigated by using the method of upper and lower solutions and comparison principle. It is shown that the globally asymptotically stale trivial solution (0,0 when *, the globally asymptotically stale semi-trival periodic solutions *, of the system by construction of a pair of upper and lower solution of parabolic periodic system *. It was obtained that the system have a pair of T-periodic quasi-solutions and the sector between the quasi-solutions is an attractor of the system with respect to very nonnegative initial function.(* Indicates a formula, please see the full text

XU Tian-hua

2010-11-01

149

Cost minimization for periodic maintenance policy of a system subject to slow degradation  

International Nuclear Information System (INIS)

This paper considers a repairable system which undergoes preventive maintenance (PM) periodically and is minimally repaired at each failure. Most preventive maintenance models assume that the system improves at each PM so that the hazard rate is reduced to that of a new system or to some specified level. In this paper, we consider the situation where each PM relieves stress temporarily and hence slows the rate of system degradation, while the hazard rate of the system remains monotonically increasing. The optimal number and period for the periodic PM that minimize the expected cost rate per unit time over an infinite time span are obtained. We also consider the case when the minimal repair cost varies with time. Explicit solutions for the optimal periodic PM are given for the Weibull distribution case

150

On angular momentum balance for particle systems with periodic boundary conditions  

CERN Document Server

The well-known issue with the absence of conservation of angular momentum in classical particle systems with periodic boundary conditions is addressed. It is proposed to consider the periodic cell as an open system, exchanging mass, momentum, angular momentum, and energy with surrounding cells. Then the behavior of the cell is described by balance laws rather than conservation laws. It is shown using the law of angular momentum balance that the variation of the angular momentum in systems with periodic boundary conditions is a consequence of the non-zero flux of angular momentum through the boundaries.

Kuzkin, Vitaly A

2013-01-01

151

Emergence of quasiperiodicity in symmetrically coupled, identical period-doubling systems  

DEFF Research Database (Denmark)

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. As a consequence the Feigenbaum transition to chaos in these coupled systems-which exists, but tends to be unstable-is accompanied by an infinity of Hopf bifurcations.

Reick, Christian; Mosekilde, Erik

1995-01-01

152

Self-similarities of periodic structures for a discrete model of a two-gene system  

International Nuclear Information System (INIS)

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.

153

Existence of Periodic Solutions of Linear Hamiltonian Systems with Sublinear Perturbation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigate the existence of periodic solutions of linear Hamiltonian systems with a nonlinear perturbation. Under generalized Ahmad-Lazer-Paul type coercive conditions for the nonlinearity on the kernel of the linear part, existence of periodic solutions is obtained by saddle point theorems. A note on a result of Rabinowitz is also given.

Zhiqing Han

2010-01-01

154

Existence of Periodic Solutions of Linear Hamiltonian Systems with Sublinear Perturbation  

Directory of Open Access Journals (Sweden)

Full Text Available We investigate the existence of periodic solutions of linear Hamiltonian systems with a nonlinear perturbation. Under generalized Ahmad-Lazer-Paul type coercive conditions for the nonlinearity on the kernel of the linear part, existence of periodic solutions is obtained by saddle point theorems. A note on a result of Rabinowitz is also given.

Zhiqing Han

2010-01-01

155

Theoretical Basis and Correct Explanation of the Periodic System: Review and Update  

Science.gov (United States)

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…

Schwarz, W. H. Eugen; Rich, Ronald L.

2010-01-01

156

Hopf-pitchfork bifurcation and periodic phenomena in nonlinear financial system with delay  

International Nuclear Information System (INIS)

Highlights: ? We derive the unfolding of a financial system with Hopf-pitchfork bifurcation. ? We show the coexistence of a pair of stable small amplitudes periodic solutions. ? At the same time, also there is a pair of stable large amplitudes periodic solutions. ? Chaos can appear by period-doubling bifurcation far away from Hopf-pitchfork value. ? The study will be useful for interpreting economics phenomena in theory. - Abstract: In this paper, we identify the critical point for a Hopf-pitchfork bifurcation in a nonlinear financial system with delay, and derive the normal form up to third order with their unfolding in original system parameters near the bifurcation point by normal form method and center manifold theory. Furthermore, we analyze its local dynamical behaviors, and show the coexistence of a pair of stable periodic solutions. We also show that there coexist a pair of stable small-amplitude periodic solutions and a pair of stable large-amplitude periodic solutions for different initial values. Finally, we give the bifurcation diagram with numerical illustration, showing that the pair of stable small-amplitude periodic solutions can also exist in a large region of unfolding parameters, and the financial system with delay can exhibit chaos via period-doubling bifurcations as the unfolding parameter values are far away from the critical point of the Hopf-pitchfork bifurcation.

157

Positive almost periodic solutions of non-autonomous delay competitive systems with weak Allee effect  

Directory of Open Access Journals (Sweden)

Full Text Available By using Mawhin's continuation theorem of coincidence degree theory, we obtain sufficient conditions for the existence of positive almost periodic solutions for a non-autonomous delay competitive system with weak Allee effect.

Yongkun Li

2009-08-01

158

Periodic solutions of non-autonomous second order systems with p-Laplacian  

Directory of Open Access Journals (Sweden)

Full Text Available We prove the existence of periodic solutions for non-autonomous second order systems with p-Laplacian. Our main tools are the minimax methods in critical point theory. Our results are new, even when p=2.

Jihui Zhang

2009-01-01

159

Existence of three positive periodic solutions for differential systems with feedback controls on time scales  

Directory of Open Access Journals (Sweden)

Full Text Available Using the Leggett-Williams multiple fixed point theorem, we establish criteria for the existence of three positive periodic solutions of a class of differential systems with feedback controls on time scales.

Yongkun Li

2010-08-01

160

Periodic orbits in non-integrable hamiltoniam systems with two degrees of freedom  

International Nuclear Information System (INIS)

We present extensive numerical data concerning the periodics orbits of a non integrable two degrees of freedom hamiltoniam system. These periodics orbits form a one-parameter family and the data are displayed in a plot of energy x period. These orbits exhibit several kinds of bifurcations not predicted in the generic study by K.R. Meyer (Trans. Am. Math. Soc., 1970) due to the existence of symmetries in the hamiltonian. Using a perturbative treatment in the neighbourhood of the periodic trajectories, we analytically compute the effect of these symmetries in the bifurcations. These results are in perfect agreement with those obtained numerically. (author)

 
 
 
 
161

Control of nonlinear systems using periodic parametric perturbations with application to a reversed field pinch  

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

162

Research on anti-disturbance property of HFETRC period monitoring system  

International Nuclear Information System (INIS)

The anti-disturbance problem of the period monitoring system for test reactor critical assembly is mainly discussed and how to judge and search for the interference source using spotting experimental methods starting from the practical engineering without special equipment is introduced. So the electro-magnetic interference is removed. After finding out the reason, four measures are adopted to build up the anti-disturbance ability of the period monitoring system. (authors)

163

Tracking unstable periodic orbits in nonstationary high-dimensional chaotic systems:Method and experiment  

Science.gov (United States)

We consider the adaptive control of chaos in nonstationary high-dimensional dynamical systems. In particular, we propose and experimentally implement a technique to stabilize and track unstable periodic orbits based on the use of time series. In our technique, the position of the periodic orbit and other parameters in the controller are continually updated from recent measurements of the system state and perturbation histories, while the environment, simulated by one or several of the system's parameters, drifts independent of the control algorithm. We demonstrate the effectiveness of the technique computationally for the Hénon map, a chemical reaction model, and a coupled driven Duffing oscillator, and experimentally for a magnetoelastic ribbon system.

Gluckman, Bruce J.; Spano, Mark L.; Yang, Weiming; Ding, Mingzhou; in, Visarath; Ditto, William L.

1997-05-01

164

Stable 1 2 Resonant Periodic Orbits in Elliptic Three-Body Systems  

CERN Document Server

The results of an extensive numerical study of the periodic orbits of planar, elliptic restricted three-body planetary systems consisting of a star, an inner massive planet and an outer mass-less body in the external 1:2 mean-motion resonance are presented. Using the method of differential continuation, the locations of the resonant periodic orbits of such systems are identified and through an extensive study of their phase-parameter space, it is found that the majority of the resonant periodic orbits are unstable. For certain values of the mass and the orbital eccentricity of the inner planet, however, stable periodic orbits can be found. The applicability of such studies to the 1:2 resonance of the extrasolar planetary system GJ876 is also discussed.

Haghighipour, N; Varadi, F; Moore, W B; Haghighipour, Nader; Couetdic, Jocelyn; Varadi, Ferenc; Moore, William B.

2003-01-01

165

Continuation and stability deduction of resonant periodic orbits in three dimensional systems  

CERN Document Server

In dynamical systems of few degrees of freedom, periodic solutions consist the backbone of the phase space and the determination and computation of their stability is crucial for understanding the global dynamics. In this paper we study the classical three body problem in three dimensions and use its dynamics to assess the long-term evolution of extrasolar systems. We compute periodic orbits, which correspond to exact resonant motion, and determine their linear stability. By computing maps of dynamical stability we show that stable periodic orbits are surrounded in phase space with regular motion even in systems with more than two degrees of freedom, while chaos is apparent close to unstable ones. Therefore, families of stable periodic orbits, indeed, consist backbones of the stability domains in phase space.

Antoniadou, Kyriaki I; Varvoglis, Harry

2014-01-01

166

V456 Ophiuchi and V490 Cygni: Systems with the shortest apsidal-motion periods  

CERN Document Server

Our main aim is the first detailed analysis of the two eclipsing binaries V456 Oph and V490 Cyg. The system V456 Oph has been studied both photometrically via an analysis of its light curve observed by the INTEGRAL/OMC and by the period analysis of all available times of minima. V490 Cyg has been studied by means of a period analysis only. Many new times of minima for both systems have recently been observed and derived. This allows us for the first time to study in detail the processes that affect both binaries. The main result is the discovery that both systems have eccentric orbits. For V456 Oph we deal with the eccentric eclipsing binary system with the shortest orbital period known (about 1.016 day), while the apsidal motion period is about 23 years. V490 Cyg represents the eclipsing system with the shortest apsidal motion period (about 18.8 years only). The two components of V456 Oph are probably of spectral type F. We compare and discuss the V456 Oph results from the light curve and the period analysis...

Zasche, P; 10.1051/0004-6361/201015720

2011-01-01

167

V456 Ophiuchi and V490 Cygni: Systems with the shortest apsidal-motion periods  

Science.gov (United States)

Our main aim is the first detailed analysis of the two eclipsing binaries V456 Oph and V490 Cyg. The system V456 Oph has been studied both photometrically via an analysis of its light curve observed by the INTEGRAL/OMC and by the period analysis of all available times of minima. V490 Cyg has been studied by means of a period analysis only. Many new times of minima for both systems have recently been observed and derived. This allows us for the first time to study in detail the processes that affect both binaries. The main result is the discovery that both systems have eccentric orbits. For V456 Oph we deal with the eccentric eclipsing binary system with the shortest orbital period known (about 1.016 day), while the apsidal motion period is about 23 years. V490 Cyg represents the eclipsing system with the shortest apsidal motion period (about 18.8 years only). The two components of V456 Oph are probably of spectral type F. We compare and discuss the V456 Oph results from the light curve and the period analysis, but a more detailed spectroscopy is needed to confirm the physical parameters of the components more precisely.

Zasche, P.; Wolf, M.

2011-03-01

168

An algorithm for detecting percolating structures in periodic systems - Application to polymer networks  

Science.gov (United States)

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 becomes solid-like. This problem is similar to that of finding connected paths in lattice bond percolation and site percolation models. We show that algorithms that detect these structures in finite systems will not always yield the correct answer for a system that is periodically repeated in space (uses periodic boundary conditions). Here we describe an algorithm that detects clusters that connect to themselves over an arbitrary number of periodic replicas. Because of the periodic replication this means that they are connected over all space. For system sizes that are typically tractable in simulations we find a relatively minor proportion of configurations are mis-classified for a lattice model. However, the fraction that is mis-classified is significant for the polymer system. Mis-classified configurations when included in the calculation of ensemble averages will include configurations with spurious physical properties. Our algorithm allows this to be corrected for.

Koopman, E. A.; Lowe, C. P.

2014-10-01

169

H2 OPTIMAL CONTROLLERS FOR A LARGE CLASS OF LINEAR STOCHASTIC SYSTEMS WITH PERIODIC COEFFICIENTS  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper the H2 type optimization problem for a class of timevarying linear stochastic systems modeled by Ito differential equations and Markovian jumping with periodic coefficients is considered. The main goal of such an optimization problem is to minimize the effect of additive white noise perturbations on a suitable output of the controlled system. It is assumed that only an output is available for measurements.The solution of the considered optimization problem is constructed via the stabilizing solutions of some suitable systems of generalized Riccati differential equations with periodic coefficients.

Adrian-Mihail Stoica

2011-07-01

170

Implementing Multi-Periodic Critical Systems: from Design to Code Generation  

Directory of Open Access Journals (Sweden)

Full Text Available This article presents a complete scheme for the development of Critical Embedded Systems with Multiple Real-Time Constraints. The system is programmed with a language that extends the synchronous approach with high-level real-time primitives. It enables to assemble in a modular and hierarchical manner several locally mono-periodic synchronous systems into a globally multi-periodic synchronous system. It also allows to specify flow latency constraints. A program is translated into a set of real-time tasks. The generated code (C code can be executed on a simple real-time platform with a dynamic-priority scheduler (EDF. The compilation process (each algorithm of the process, not the compiler itself is formally proved correct, meaning that the generated code respects the real-time semantics of the original program (respect of periods, deadlines, release dates and precedences as well as its functional semantics (respect of variable consumption.

Julien Forget

2010-03-01

171

Implementing Multi-Periodic Critical Systems: from Design to Code Generation  

CERN Document Server

This article presents a complete scheme for the development of Critical Embedded Systems with Multiple Real-Time Constraints. The system is programmed with a language that extends the synchronous approach with high-level real-time primitives. It enables to assemble in a modular and hierarchical manner several locally mono-periodic synchronous systems into a globally multi-periodic synchronous system. It also allows to specify flow latency constraints. A program is translated into a set of real-time tasks. The generated code (\\C\\ code) can be executed on a simple real-time platform with a dynamic-priority scheduler (EDF). The compilation process (each algorithm of the process, not the compiler itself) is formally proved correct, meaning that the generated code respects the real-time semantics of the original program (respect of periods, deadlines, release dates and precedences) as well as its functional semantics (respect of variable consumption).

Forget, Julien; Lesens, David; Pagetti, Claire

2010-01-01

172

Fast computation of the Maslov index for hyperbolic linear systems with periodic coefficients  

International Nuclear Information System (INIS)

The Maslov index is a topological property of periodic orbits of finite-dimensional Hamiltonian systems that is widely used in semiclassical quantization, quantum chaology, stability of waves and classical mechanics. The Maslov index is determined from the analysis of a linear Hamiltonian system with periodic coefficients. In this paper, a numerical scheme is devised to compute the Maslov index for hyperbolic linear systems when the phase space has a low dimension. The idea is to compute on the exterior algebra of the ambient vector space, where the Lagrangian subspace representing the unstable subspace is reduced to a line. When the exterior algebra is projectified the Lagrangian subspace always forms a closed loop. The idea is illustrated by application to Hamiltonian systems on a phase space of dimension 4. The theory is used to compute the Maslov index for the spectral problem associated with periodic solutions of the fifth-order Korteweg de Vries equation

173

Existence and global attractivity of positive periodic solution for competition-predator system with variable delays  

International Nuclear Information System (INIS)

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

174

Stabilizing periodic orbits of chaotic systems using fuzzy adaptive sliding mode control  

Energy Technology Data Exchange (ETDEWEB)

In this paper by using a combination of fuzzy identification and the sliding mode control a fuzzy adaptive sliding mode scheme is designed to stabilize the unstable periodic orbits of chaotic systems. The chaotic system is assumed to have an affine form x{sup (n)} = f(X) + g(X)u where f and g are unknown functions. Using only the input-output data obtained from the underlying dynamical system, two fuzzy systems are constructed for identification of f and g. Two distinct methods are utilized for fuzzy modeling, the least squares and the gradient descent techniques. Based on the estimated fuzzy models, an adaptive controller, which works through the sliding mode control, is designed to make the system track the desired unstable periodic orbits. The stability analysis of the overall closed loop system is presented in the paper and the effectiveness of the proposed adaptive scheme is numerically investigated. As a case of study, modified Duffing system is selected for applying the proposed method to stabilize its 2{pi} and 4{pi} periodic orbits. Simulation results show the high performance of the method for stabilizing the unstable periodic orbits of unknown chaotic systems.

Layeghi, Hamed [Department of Mechanical Engineering, Sharif University of Technology, Center of Excellence in Design, Robotics and Automation, Azadi Avenue, Postal Code 11365-9567 Tehran (Iran, Islamic Republic of)], E-mail: layeghi@mech.sharif.edu; Arjmand, Mehdi Tabe [Department of Mechanical Engineering, Sharif University of Technology, Center of Excellence in Design, Robotics and Automation, Azadi Avenue, Postal Code 11365-9567 Tehran (Iran, Islamic Republic of)], E-mail: arjmand@mech.sharif.edu; Salarieh, Hassan [Department of Mechanical Engineering, Sharif University of Technology, Center of Excellence in Design, Robotics and Automation, Azadi Avenue, Postal Code 11365-9567 Tehran (Iran, Islamic Republic of)], E-mail: salarieh@mech.sharif.edu; Alasty, Aria [Department of Mechanical Engineering, Sharif University of Technology, Center of Excellence in Design, Robotics and Automation, Azadi Avenue, Postal Code 11365-9567 Tehran (Iran, Islamic Republic of)], E-mail: aalasti@sharif.edu

2008-08-15

175

Quasilinearization for the periodic boundary value problem for systems of impulsive differential equations  

Directory of Open Access Journals (Sweden)

Full Text Available The method of generalized quasilinearization for the system of nonlinear impulsive differential equations with periodic boundary conditions is studied. As a byproduct, the result for the system without impulses can be obtained, which is a new result as well.

S. G. Hristova

2006-01-01

176

Stabilizing periodic orbits of chaotic systems using fuzzy adaptive sliding mode control  

International Nuclear Information System (INIS)

In this paper by using a combination of fuzzy identification and the sliding mode control a fuzzy adaptive sliding mode scheme is designed to stabilize the unstable periodic orbits of chaotic systems. The chaotic system is assumed to have an affine form x(n) = f(X) + g(X)u where f and g are unknown functions. Using only the input-output data obtained from the underlying dynamical system, two fuzzy systems are constructed for identification of f and g. Two distinct methods are utilized for fuzzy modeling, the least squares and the gradient descent techniques. Based on the estimated fuzzy models, an adaptive controller, which works through the sliding mode control, is designed to make the system track the desired unstable periodic orbits. The stability analysis of the overall closed loop system is presented in the paper and the effectiveness of the proposed adaptive scheme is numerically investigated. As a case of study, modified Duffing system is selected for applying the proposed method to stabilize its 2? and 4? periodic orbits. Simulation results show the high performance of the method for stabilizing the unstable periodic orbits of unknown chaotic systems

177

Systematic search of symmetric periodic orbits in 2DOF Hamiltonian systems  

International Nuclear Information System (INIS)

In this paper, we study in detail the grid search numerical method to locate symmetric periodic orbits in Hamiltonian systems of two degrees of freedom. The method is based on the classical search method but combining up-to-date numerical algorithms in the search and in the integration process. Instead of using Newton methods that requires to differentiate the Poincare map we use the Brent's method and in the integration process a Taylor series method that permits us to compute the orbits using extended precision, something highly interesting in the case of unstable periodic orbits. These facts have permitted us to obtain much more periodic orbits than other researchers. Once the families of periodic orbits have been found we study the bifurcations just by comparing with the stability index and the classical generic bifurcations for Hamiltonian systems with and without symmetries. We illustrate the method with four important classical Hamiltonian problems.

178

Model reduction of nonlinear systems with external periodic excitations via construction of invariant manifolds  

Science.gov (United States)

A methodology for determining reduced order models of periodically excited nonlinear systems with constant as well as periodic coefficients is presented. The approach is based on the construction of an invariant manifold such that the projected dynamics is governed by a fewer number of ordinary differential equations. Due to the existence of external and parametric periodic excitations, however, the geometry of the manifold varies with time. As a result, the manifold is constructed in terms of temporal and dominant state variables. The governing partial differential equation (PDE) for the manifold is nonlinear and contains time-varying coefficients. An approximate technique to find solution of this PDE using a multivariable Taylor-Fourier series is suggested. It is shown that, in certain cases, it is possible to obtain various reducibility conditions in a closed form. The case of time-periodic systems is handled through the use of Lyapunov-Floquet (L-F) transformation. Application of the L-F transformation produces a dynamically equivalent system in which the linear part of the system is time-invariant; however, the nonlinear terms get multiplied by a truncated Fourier series containing multiple parametric excitation frequencies. This warrants some structural changes in the proposed manifold, but the solution procedure remains the same. Two examples; namely, a 2-dof mass-spring-damper system and an inverted pendulum with periodic loads, are used to illustrate applications of the technique for systems with constant and periodic coefficients, respectively. Results show that the dynamics of these 2-dof systems can be accurately approximated by equivalent 1-dof systems using the proposed methodology.

Gabale, Amit P.; Sinha, S. C.

2011-05-01

179

Confrontation between Quantized Periods of Some Extra-Solar Planetary Systems and Observations  

Directory of Open Access Journals (Sweden)

Full Text Available A simple formula, using the quantum numbers of solar system planets and some quantized extra-solar planets, to estimate the periods, is done. The quantum numbers, calculated by other authors, have been used to find the orbital periods of solar system planets and some extra-solar planets. Observed periods have been used to compare them with the estimated periods from the given formula. It is found that the given relation is applicable perfectly for the solar system planets. Some extra-solar planets, of stars having approximately the same mass as the sun, are chosen to apply the same relation. The differences between the observed and calculated periods for the extra-solar systems have been calculated and tabulated. It is found that the percentage errors between the predicted values and the corresponding observed values for extra-planetary systems are controlled by the star’s mass and its quantum number. The percentage error decreases by increasing the quantum number, for quantum numbers over 4. When the quantum number is less than or equal 4, it is found that the percentage error decreases by decreasing the quantum number.

A. B. Morcos

2013-06-01

180

Phase-shift inversion in oscillator systems with periodically switching couplings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A system's response to external periodic changes can provide crucial information about its dynamical properties. We investigate the synchronization transition, an archetypical example of a dynamic phase transition, in the framework of such a temporal response. The Kuramoto model under periodically switching interactions has the same type of phase transition as the original mean-field model. Furthermore, we see that the signature of the synchronization transition appears in t...

Lee, Sang Hoon; Lee, Sungmin; Son, Seung-woo; Holme, Petter

2011-01-01

 
 
 
 
181

Phase-shift inversion in oscillator systems with periodically switching couplings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A system's response to external periodic changes can provide crucial information about its dynamical properties. We investigate the synchronization transition, an archetypical example of a dynamic phase transition, in the framework of such a temporal response. The Kuramoto model under periodically switching interactions has the same type of phase transition as the original mean-field model. Furthermore, we see that the signature of the synchronization transition appears in the relative delay ...

Lee, Sang Hoon; Lee, Sungmin; Son, Seung-woo; Holme, Petter

2012-01-01

182

DISK-PLANETS INTERACTIONS AND THE DIVERSITY OF PERIOD RATIOS IN KEPLER'S MULTI-PLANETARY SYSTEMS  

International Nuclear Information System (INIS)

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

183

Globally and locally attractive solutions for quasi-periodic ally forced systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We consider a class of differential equations, x + yx + g(x) = f(omega t), with omega is an element of R-d, 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) = x(2p+1), p is an element of N, we show that, when the dissipation coefficient is large enough, there is only one such trajectory and that it describes a global attractor....

Bartuccelli, Mv; Deane, Jhb; Gentile, G.

2007-01-01

184

A 19-h spontaneous sleep period in idiopathic central nervous system hypersomnia.  

Science.gov (United States)

Reports of prolonged sleep periods in idiopathic central nervous system hypersomnia, as shown by ad libitum sleep recordings, are rare. A patient with idiopathic hypersomnia with extremely long sleep periods and sleep drunkenness after awakening is described. Polysomnographic recordings showed a spontaneous sleep period of 19.4 h and a normal Multiple Sleep Latency Test. These polysomnographic findings are clearly abnormal but essentially different form those of narcolepsy. Unlike narcolepsy, 'idiopathic hypersomnia' does not seem to be a distinct clinical entity but a category for different heterogenous subtypes. PMID:9682181

Voderholzer, U; Backhaus, J; Hornyak, M; Hohagen, F; Berger, M; Riemann, D

1998-06-01

185

A review of transparent insulation systems and the evaluation of payback period for building applications  

Energy Technology Data Exchange (ETDEWEB)

Research and development of transparent insulation systems (TI-systems) has been ongoing for 20 years with transparent insulation materials (TIMs) used to replace standard opaque insulation materials. TIM not only performs similar functions to opaque insulation, reducing heat losses and controlling indoor temperatures, but allows solar transmittance of more than 50%. With a thickness of less than 20 cm, it can provide a financial return to building occupants when applied to building facades, maximising occupiable and sellable spaces in urban areas, without compromising thermal comfort within buildings. In this review of TI-systems for building applications, drawbacks to previous applications, cost trends, and analysis of the limitation in information from previous studies are discussed. A major drawback in the development of TI-systems identified is the lack of cost information; the payback periods for TI-systems used in previous renovation projects are virtually unknown. Simple payback period calculations were undertaken based on information available from a demonstration project documented by the Solar Heating and Cooling (SHC) Programme of the International Energy Agency (IEA) Task 20 'Solar Energy in Building Renovation'. The calculations indicated an encouraging 5-8-year payback period for this particular case study. It was concluded that the simple payback period calculation may be used for feasibility studies to indicate the time required to recoup investment when installing TI-systems and to provide initial guidance for building designers when evaluating the potential application of TI-systems in their buildings. (author)

Wong, I.L.; Perera, R.S. [Centre for Sustainable Technologies, University of Ulster, Newtownabbey, Co. Antrim BT37 0QB (United Kingdom); Eames, P.C. [Warwick Institute for Sustainable Energy and Resources, School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom)

2007-09-15

186

Minimisation of Non-periodic Preventive Maintenance Cost in Series-parallel Systems  

Directory of Open Access Journals (Sweden)

Full Text Available A new method to optimise the non-periodic preventive maintenance model of a series-parallel system is proposed. A two-stage algorithm that incorporates the failure limit policy to determine maintenance components, maintenance times, and total maintenance cost is suggested. When the reliability of the system reaches a threshold value, preventive maintenance is performed. The first stage identifies the parallel sub-system required to be maintained, while the second stage determines the component required to be maintained in the parallel sub-system. A unit-cost life index (UCL has been developed to evaluate the extent to which maintaining a component extends the life of a system for the parallel subsystem. Three simulated cases demonstrate the effectiveness and the practicality of the proposed method in optimising the non-periodic preventive maintenance model of a series-parallel system.

Chung-Ho Wang

2011-01-01

187

Numerical detection of unstable periodic orbits in continuous-time dynamical systems with chaotic behaviors  

Directory of Open Access Journals (Sweden)

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.

Y. Saiki

2007-09-01

188

Human error considerations and annunciator effects in determining optimal test intervals for periodically inspected standby systems  

International Nuclear Information System (INIS)

This paper incorporates the effects of four types of human error in a model for determining the optimal time between periodic inspections which maximizes the steady state availability for standby safety systems. Such safety systems are characteristic of nuclear power plant operations. The system is assumed to possess the following characteristics: (1) system failures occur according to a specified lifetime distribution, while on standby, which may have a time-dependent failure rate. The system may include a detection/annunciator device which will announce a failure with a known constant probability; (2) the system is periodically inspected for failures which may not have been detected by the annunciator; (3) four types of human errors may occur in the inspection/repair process: the system may not be correctly replaced on-line after inspection; repair (type A error); a failed system may be judged good during a periodic inspection (type B error); a failed system may be improperly repaired (type C error); or the failure causing an annunciator-activated inspection may not be located (type D error); (4) inspection times are assumed fixed and known; (5) repair times are assumed to have a lognormal distribution. The system described above is modeled by means of an infinite state-space Markov chain. The purpose of the paper is to demonstrate techniques for computing steady-state availability A and the optimal periodic inspection interval tau* for the system described above. The model can be used to investigate the effects of human error probabilities on optimal availability, study the benefits of annunciating the standby-system, and to determine optimal inspection intervals. Several examples which are representative of nuclear power plant applications are presented

189

Periodic solutions for small and large delays in a tumor-immune system model  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper we study the Hopf bifurcation for the tumor-immune system model with one delay. This model is governed by a system of two differential equations with one delay. We show that the system may have periodic solutions for small and large delays for some critical value of the delay parameter via Hopf bifurcation theorem bifurcating from the non trivial steady state.

Radouane Yafia

2006-09-01

190

Busy Period Analysis of a Man-machine System Operating Subject To Different Physical Conditions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. Severa...

Mokaddis, G. S.; Tawfek, M. L.; Elhssia, S. A. M.

2005-01-01

191

Generalized scattering-matrix approach for magneto-optics in periodically patterned multilayer systems  

CERN Document Server

We present here a generalization of the scattering-matrix approach for the description of the propagation of electromagnetic waves in nanostructured magneto-optical systems. Our formalism allows us to describe all the key magneto-optical effects in any configuration in periodically patterned multilayer structures. The method can also be applied to describe periodic multilayer systems comprising materials with any type of optical anisotropy. We illustrate the method with the analysis of a recent experiment in which the transverse magneto-optical Kerr effect was measured in a Fe film with a periodic array of subwavelength circular holes. We show, in agreement with the experiments, that the excitation of surface plasmon polaritons in this system leads to a resonant enhancement of the transverse magneto-optical Kerr effect.

Caballero, B; Cuevas, J C

2012-01-01

192

Pattern formation in liquid-vapor systems under periodic potential and shear.  

Science.gov (United States)

In this paper the phase behavior and pattern formation in a sheared nonideal fluid under a periodic potential is studied. An isothermal two-dimensional formulation of a lattice Boltzmann scheme for a liquid-vapor system with the van der Waals equation of state is presented and validated. Shear is applied by moving walls and the periodic potential varies along the flow direction. A region of the parameter space, where in the absence of flow a striped phase with oscillating density is stable, will be considered. At low shear rates the periodic patterns are preserved and slightly distorted by the flow. At high shear rates the striped phase loses its stability and traveling waves on the interface between the liquid and vapor regions are observed. These waves spread over the whole system with wavelength only depending on the length of the system. Velocity field patterns, characterized by a single vortex, will also be shown. PMID:25019908

Coclite, A; Gonnella, G; Lamura, A

2014-06-01

193

Modal Vibration Control in Periodic Time-Varying Structures with Focus on Rotor Blade Systems  

DEFF Research Database (Denmark)

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 to be overcome. Among others it is necessary, that the control scheme is capable to cope with non-linear time-varying dynamical system behaviour. However, rotating at constant speed the mathematical model becomes periodic time-variant. In this framework the present paper gives a contribution to design procedures 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 is reformulated using complex mode theory. Next, a linear constant gain controller for the reformulated system is designed by linear control technique. Finally, this constant gain controller is transformed to a time-periodic form by applying reverse modal transformation. The non-measurable states are estimated using a periodic time-varying state observer designed by a methodology similar to the controller design. Furthermore, the modal matrices are used to analyse the controllability of the system in order to determine optimal actuator placement in the system. For this the modal transform technique is a very effective tool. The control design methodology is applied to a coupled rotor-blade system to demonstrate the efficiency of such a procedure. A simulation model for the system is formulated and a time-periodic modal controller is designed using the described methodology. Simulation results are provided to demonstrate the applicability and effectiveness of the technique. The results obtained shows that the control design technique is capable to cope with the time periodicity of this class of systems.

Christensen, Rene Hardam; Santos, Ilmar

2004-01-01

194

Modal Vibration Control in Periodic Time-Varying Structures with Focus on Rotor-Blade Systems  

DEFF Research Database (Denmark)

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 to be overcome. Among others it is necessary, that the control scheme is capable to cope with non-linear time-varying dynamical system behaviour. However, rotating at constant speed the mathematical model becomes periodic time-variant. In this framework the present paper gives a contribution to design procedures 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 is reformulated using complex mode theory. Next, a linear constant gain controller for the reformulated system is designed by linear control technique. Finally, this constant gain controller is transformed to a time-periodic form by applying reverse modal transformation. The non-measurable states are estimated using a periodic time-varying state observer designed by a methodology similar to the controller design. Furthermore, the modal matrices are used to analyse the controllability of the system in order to determine optimal actuator placement in the system. For this the modal transform technique is a very effective tool. The control design methodology is applied to a coupled rotor-blade system to demonstrate the efficiency of such a procedure. A simulation model for the system is formulated and a time-periodic modal controller is designed using the described methodology. Simulation results are provided to demonstrate the applicability and effectiveness of the technique. The results obtained shows that the control design technique is capable to cope with the time periodicity of this class of systems.

Christensen, Rene Hardam; Santos, Ilmar

2003-01-01

195

Influence of external periodic and non-linear factors upon stability of economic systems ??????? ??????? ????????????? ? ?????????? ???????? ?? ???????????? ????????????? ??????  

Directory of Open Access Journals (Sweden)

Full Text Available The article conducts a study of influence of periodic effect upon economic systems. It shows a danger of the resonance case when frequency of external periodic effect on the system tends to its own frequency of vibrations near the state of equilibrium. In this case, the amplitude of vibrations of the system becomes proportional to time and grows with it. Account of impacts, proportional to the rate of shift from the state of equilibrium, results in limitation of growth of the amplitude of vibrations, taking away secular dependence. Account of actions, proportional to non-linear shifts from the point of equilibrium, points out a possibility of taking the system out of the resonance. Quadratic non-linearity has no influence upon changes of the amplitude and vibration phase and cubic non-linearity changes the vibration phase through the amplitude, which takes the system out of the resonance. Depending on the system parameters, the case of a sudden change of the amplitude during the change of difference between the own frequency of the system and frequency of periodic effect is possible, moreover, the system passes to a stable state. The article offers methods of treating monitoring data for qualitative analysis of dynamics of economic systems.????????? ???????????? ??????? ?????????????? ??????????? ?? ????????????? ???????. ???????? ????????? ???????????? ??????, ????? ??????? ???????? ?????????????? ??????????? ?? ??????? ???????????? ? ?? ??????????? ??????? ????????? ????? ????????? ??????????. ? ???? ?????? ????????? ????????? ??????? ?????????? ???????????????? ??????? ? ?????????? ?????? ? ???. ???? ???????????, ???????????????? ???????? ???????? ?? ????????? ??????????, ???????? ? ??????????? ????? ????????? ?????????, ?????? ?????????? ???????????. ???? ????????, ???????????????? ?????????? ????????? ?? ????? ??????????, ????????? ?? ??????????? ?????? ??????? ?? ?????????. ???????????? ???????????? ?? ?????? ?? ????????? ????????? ? ???? ?????????, ? ?????????? ???????????? ????? ????????? ???????? ???? ?????????, ??? ??????? ??????? ?? ?????????. ? ??????????? ?? ?????????? ???????, ???????? ?????? ?????????? ????????? ????????? ??? ????????? ???????? ????? ??????????? ???????? ??????? ? ???????? ?????????????? ???????????, ?????? ??????? ??? ???? ????????? ? ?????????? ?????????. ?????????? ???????? ????????? ?????? ??????????? ??? ????????????? ??????? ???????? ????????????? ??????.

Lapshyn Vladimir I.

2013-02-01

196

Symbolic Computation of Fundamental Solution Matrices for Linear Time-Periodic Dynamical Systems  

Science.gov (United States)

A new technique which employs both Picard iterationand expansion in shifted Chebyshev polynomialsis used to symbolically approximate the fundamental solution matrix for linear time-periodic dynamical systems of arbitrary dimension explicitly as a function of the system parameters and time. As in previous studies, the integrationand product operational matricesassociated withe Chebyshev polynomials are employed. However, the need to algebraically solve for the Chebyshev coefficients of the fundamental solution matrix is completely avoided as only matrix multiplications and additions are utilized. Since these coefficients are expressed as homogeneous polynomials of the system parameters, closed form approximations to the true solutions may be obtained. Also, because this method is notbased on expansion in terms of a small parameter, it can successfully be applied to periodic systems whose internal excitation is strong. Two formulations are proposed. The first is applicable to general time periodic systems while the second approach is useful when the system equations contain a constant matrix. Three different example problems, including a double inverted pendulum subjected to a periodic follower force, are included and CPU time and convergence results are discussed.

Sinha, S. C.; Butcher, E. A.

1997-09-01

197

Fuel management of the power plant system during the transition period  

International Nuclear Information System (INIS)

Equilibrium nuclear power plant system will be formed during a 20 to 50 year long transition period when the ratio of the thermal reactors to the fast breeder reactors is higher than in equilibrium situation. For the transition period ten different schemes for the fuel cycle are defined and analyzed depending on the power ratio of the thermal and fast reactors and the type of reactors involved in the system. Algorithms are given for the calculation of the amount of fissile material consumed, produced and stored, and of the natural uranium utilization efficiency. (V.N.) 9 figs

198

Time-independent canonical perturbation theory for nearly multiple-periodic systems  

International Nuclear Information System (INIS)

A modification of the classical canonical time-independent perturbation theory is presented for nearly multiple-periodic systems having the Hamiltonians of the form H = H0(Jsub(?)) + lambda H1(wsub(?),Jsub(?);qsub(k),psub(k)) + lambdasup(2)H2(wsub(?),Jsub(?);qsub(k),psub(k)) + ... where H1, H2, ... are periodic functions of angles wsub(?). The perturbation procedure is based on the averaging of the Hamilton-Jacobi equation over angles wsub(?). The existence of motion constants for all orders of the perturbation theory is shown for both non-degenerate and intrinsically degenerate systems. (author)

199

Human error considerations and annunciator effects in determining optimal test intervals for periodically inspected standby systems  

International Nuclear Information System (INIS)

This paper incorporates the effects of four types of human error in a model for determining the optimal time between periodic inspections which maximizes the steady state availability for standby safety systems. Such safety systems are characteristic of nuclear power plant operations. The system is modeled by means of an infinite state-space Markov chain. Purpose of the paper is to demonstrate techniques for computing steady-state availability A and the optimal periodic inspection interval tau* for the system. The model can be used to investigate the effects of human error probabilities on optimal availability, study the benefits of annunciating the standby-system, and to determine optimal inspection intervals. Several examples which are representative of nuclear power plant applications are presented

200

Stellar Rotation-Planetary Orbit Period Commensurability in the HAT-P-11 System  

Science.gov (United States)

A number of planet host stars have been observed to rotate with a period equal to an integer multiple of the orbital period of their close planet. We expand this list by analyzing Kepler data of HAT-P-11 and finding a period ratio of 6:1. In particular, we present evidence for a long-lived spot on the stellar surface that is eclipsed by the planet in the same position four times, every sixth transit. We also identify minima in the out-of-transit light curve and confirm that their phase with respect to the stellar rotation is mostly stationary for the 48 month time frame of the observations, confirming the proposed rotation period. For comparison, we apply our methods to Kepler-17 and confirm the findings of Bonomo & Lanza that the period ratio is not exactly 8:1 in that system. Finally, we provide a hypothesis on how interactions between a star and its planet could possibly result in an observed commensurability for systems where the stellar differential rotation profile happens to include a period at some latitude that is commensurable to the planetary orbit.

Béky, Bence; Holman, Matthew J.; Kipping, David M.; Noyes, Robert W.

2014-06-01

 
 
 
 
201

Stellar rotation--planetary orbit period commensurability in the HAT-P-11 system  

CERN Document Server

A number of planet-host stars have been observed to rotate with a period equal to an integer multiple of the orbital period of their close planet. We expand this list by analyzing Kepler data of HAT-P-11 and finding a period ratio of 6:1. In particular, we present evidence for a long-lived spot on the stellar surface that is eclipsed by the planet in the same position four times, every sixth transit. We also identify minima in the out-of-transit lightcurve and confirm that their phase with respect to the stellar rotation is mostly stationary for the 48-month timeframe of the observations, confirming the proposed rotation period. For comparison, we apply our methods to Kepler-17 and confirm the findings of Bonomo & Lanza (2012) that the period ratio is not exactly 8:1 in that system. Finally, we provide a hypothesis on how interactions between a star and its planet could possibly result in an observed commensurability for systems where the stellar differential rotation profile happens to include a period a...

Béky, Bence; Kipping, David M; Noyes, Robert W

2014-01-01

202

Dispersionless motion and ratchet effect in a square-wave-driven inertial periodic potential system  

Energy Technology Data Exchange (ETDEWEB)

The underdamped Langevin equation of motion of a particle, in a symmetric periodic potential and subjected to a symmetric periodic forcing with mean zero over a period, with nonuniform friction, is solved numerically. The particle is shown to acquire a steady state mean velocity at asymptotically large timescales. At these large timescales the position dispersion grows proportionally with time, t, allowing for calculating the steady state diffusion coefficient D. Interestingly, D shows a peaking behaviour around the same F{sub 0} where the net current peaks. The net (ratchet) current, however, turns out to be largely coherent. At an intermediate timescale, which bridges the small timescale behaviour of dispersion {approx}t{sup 2} to the large time one, the system shows periodic oscillation between dispersionless and steeply growing dispersion depending on the amplitude and frequency of the forcing. The contribution of these different dispersion regimes to ratchet current is analysed.

Saikia, S; Mahato, Mangal C [Department of Physics, North-Eastern Hill University, Shillong 793022 (India)], E-mail: mangal@nehu.ac.in

2009-04-29

203

Dispersionless motion and ratchet effect in a square-wave-driven inertial periodic potential system  

International Nuclear Information System (INIS)

The underdamped Langevin equation of motion of a particle, in a symmetric periodic potential and subjected to a symmetric periodic forcing with mean zero over a period, with nonuniform friction, is solved numerically. The particle is shown to acquire a steady state mean velocity at asymptotically large timescales. At these large timescales the position dispersion grows proportionally with time, t, allowing for calculating the steady state diffusion coefficient D. Interestingly, D shows a peaking behaviour around the same F0 where the net current peaks. The net (ratchet) current, however, turns out to be largely coherent. At an intermediate timescale, which bridges the small timescale behaviour of dispersion ?t2 to the large time one, the system shows periodic oscillation between dispersionless and steeply growing dispersion depending on the amplitude and frequency of the forcing. The contribution of these different dispersion regimes to ratchet current is analysed.

204

Chiral symmetry and bulk-boundary correspondence in periodically driven one-dimensional systems  

Science.gov (United States)

In periodically driven lattice systems, the effective (Floquet) Hamiltonian can be engineered to be topological; then, the principle of bulk-boundary correspondence guarantees the existence of robust edge states. However, such setups can also host edge states not predicted by the Floquet Hamiltonian. The exploration of such edge states and the corresponding unique bulk topological invariants has only recently begun. In this work we calculate these invariants for chiral symmetric periodically driven one-dimensional systems. We find simple closed expressions for these invariants, as winding numbers of blocks of the unitary operator corresponding to a part of the time evolution. This gives a robust way to tune these invariants using sublattice shifts. We illustrate our ideas on the periodically driven Su-Schrieffer-Heeger model, which, as we show, can realize a discrete-time quantum walk; this opens a useful connection between periodically driven lattice systems and discrete-time quantum walks. Our work helps interpret the results of recent simulations where a large number of Floquet Majorana fermions in periodically driven superconductors have been found.

Asbóth, J. K.; Tarasinski, B.; Delplace, P.

2014-09-01

205

Nonlinearity and periodic solution of a standard-beam balance oscillation system  

International Nuclear Information System (INIS)

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. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

206

An efficient tracer test for time-variable transit time distributions in periodic hydrodynamic systems  

Science.gov (United States)

The time-varying transport dynamics of complex hydrodynamic systems with long transit times are difficult to observe due to the need for multiple tracer injections. Where only one or two distinct tracers are available, overprinting in the output concentrations limits the injection frequency. In this letter we propose an experimental method (the Periodic Tracer Hierarchy) that allows overprinted breakthrough curves to be decomposed into contributions from multiple injections of the same tracer, so long as the transporting flow is periodic. This method allows the time-varying transit time distributions to be observed efficiently while making no a priori assumptions about the transport processes operating in the system. Simulations of transport through a soil column subject to a periodic sequence of irrigation events demonstrate that the distinct transit time distributions associated with each irrigation event can be retrieved almost exactly.

Harman, Ciaran J.; Kim, Minseok

2014-03-01

207

Can The Periods of Some Extra-Solar Planetary Systems be Quantized?  

Science.gov (United States)

A simple formula was derived before by Morcos (2013 ), to relate the quantum numbers of planetary systems and their periods. This formula is applicable perfectly for the solar system planets, and some extra-solar planets , of stars of approximately the same masses like the Sun. This formula has been used to estimate the periods of some extra-solar planet of known quantum numbers. The used quantum numbers were calculated previously by other authors. A comparison between the observed and estimated periods, from the given formula has been done. The differences between the observed and calculated periods for the extra-solar systems have been calculated and tabulated. It is found that there is an error of the range of 10% The same formula has been also used to find the quantum numbers, of some known periods, exo-planet. Keywords: Quantization; Periods; Extra-Planetary; Extra-Solar Planet REFERENCES [1] Agnese, A. G. and Festa, R. “Discretization on the Cosmic Scale Inspirred from the Old Quantum Mechanics,” 1998. http://arxiv.org/abs/astro-ph/9807186 [2] Agnese, A. G. and Festa, R. “Discretizing ups-Andro- medae Planetary System,” 1999. http://arxiv.org/abs/astro-ph/9910534. [3] Barnothy, J. M. “The Stability of the Solar Systemand of Small Stellar Systems,” Proceedings of the IAU Sympo-sium 62, Warsaw, 5-8 September 1973, pp. 23-31. [4] Morcos, A.B. , “Confrontation between Quantized Periods of Some Extra-Solar Planetary Systems and Observations”, International Journal of Astronomy and Astrophysics, 2013, 3, 28-32. [5] Nottale, L. “Fractal Space-Time and Microphysics, To-wards a Theory of Scale Relativity,” World Scientific, London, 1994. [6] Nottale , L., “Scale-Relativity and Quantization of Extra- Solar Planetary Systems,” Astronomy & Astrophysics, Vol. 315, 1996, pp. L9-L12 [7] Nottale, L., Schumacher, G. and Gay, J. “Scale-Relativity and Quantization of the Solar Systems,” Astronomy & Astrophysics letters, Vol. 322, 1997, pp. 1018-10 [8]Nottale, L. “Scale-Relativity and Quantization of Exo- planet Orbital Semi-Major Axes,” Astronomy & Astro- physics, Vol. 361, 2000, pp. 379-387.

El Fady Morcos, Abd

208

The periodically pulsed mode of operation of magnet systems in particle accelerators  

International Nuclear Information System (INIS)

Since in many applications in particle accelerator technology the beam duty factor, defined by the ratio of beam pulse length to the pulse to pulse period, is very small- typically in the order of 10-3 to 10-9 - it is interesting to operate the beam optical magnetic system in the periodically pulsed mode as well. Thus, by reducing the average Ohmic losses, it is possible to save energy and material. The pulsed mode of operation of magnet systems is especially adapted to those of linear accelerators and their beam transport systems, since linear accelerators are exclusively operated in this mode. But it is equally suitable for transport systems between cyclic accelerators and large storage rings as they are under development at present. (orig./WL)

209

Global Clock, Physical Time Order and Pending Period Analysis in Multiprocessor Systems  

CERN Document Server

In multiprocessor systems, various problems are treated with Lamport's logical clock and the resultant logical time orders between operations. However, one often needs to face the high complexities caused by the lack of logical time order information in practice. In this paper, we utilize the \\emph{global clock} to infuse the so-called \\emph{pending period} to each operation in a multiprocessor system, where the pending period is a time interval that contains the performed time of the operation. Further, we define the \\emph{physical time order} for any two operations with disjoint pending periods. The physical time order is obeyed by any real execution in multiprocessor systems due to that it is part of the truly happened operation orders restricted by global clock, and it is then proven to be independent and consistent with traditional logical time orders. The above novel yet fundamental concepts enables new effective approaches for analyzing multiprocessor systems, which are named \\emph{pending period analy...

Chen, Yunji; Hu, Weiwu

2009-01-01

210

Existence of periodic solutions for non-autonomous second-order Hamiltonian systems  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this paper is to study the existence of periodic solutions for a class of non-autonomous second order Hamiltonian systems. New results are obtained by using the least action principle and the minimax methods, without the so-called Ahmad-Lazer-Paul type condition.

Yue Wu

2013-03-01

211

Periodic solutions for nonautonomous second order Hamiltonian systems with sublinear nonlinearity  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Some existence and multiplicity of periodic solutions are obtained for nonautonomous second order Hamiltonian systems with sublinear nonlinearity by using the least action principle and minimax methods in critical point theory. Mathematics Subject Classification (2000: 34C25, 37J45, 58E50.

Zhang Jihui

2011-01-01

212

Two Point Correlation Functions for a Periodic Box-Ball System  

Directory of Open Access Journals (Sweden)

Full Text Available We investigate correlation functions in a periodic box-ball system. For the second and the third nearest neighbor correlation functions, we give explicit formulae obtained by combinatorial methods. A recursion formula for a specific N-point functions is also presented.

Jun Mada

2011-03-01

213

Formation of nonlinear holographic images in a system of periodically located nonlinear mediums  

Directory of Open Access Journals (Sweden)

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.

Belkov S.A.

2013-11-01

214

A New Method for Studying the Periodic System Based on a Kohonen Neural Network  

Science.gov (United States)

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…

Chen, David Zhekai

2010-01-01

215

Periodic dynamics of delayed Lotka–Volterra competition systems with discontinuous harvesting policies via differential inclusions  

International Nuclear Information System (INIS)

Highlights: • A more practical form of harvesting management policy (DHP) has been proposed. • We analyze the periodic dynamics of a class of discontinuous and delayed Lotka–Volterra competition systems. • We present a new method to obtain the existence of positive periodic solutions via differential inclusions. • The global convergence in measure of harvesting solution is discussed. -- Abstract: This paper considers a general class of delayed Lotka–Volterra competition systems where the harvesting policies are modeled by discontinuous functions or by non-Lipschitz functions. By means of differential inclusions theory, cone expansion and compression fixed point theorem of multi-valued maps and nonsmooth analysis theory with generalized Lyapunov approach, a series of useful criteria on existence, uniqueness and global asymptotic stability of the positive periodic solution is established for the delayed Lotka–Volterra competition systems with discontinuous right-hand sides. Moreover, the global convergence in measure of harvesting solution is discussed. Our results improve and extend previous works on periodic dynamics of delayed Lotka–Volterra competition systems with not only continuous or even Lipschitz continuous but also discontinuous harvesting functions. Finally, we give some corollaries and numerical examples to show the applicability and effectiveness of the proposed criteria

216

Sufficient and necessary condition for the permanence of periodic predator-prey system  

Directory of Open Access Journals (Sweden)

Full Text Available We consider the permanence of a periodic predator-prey system, where the prey disperse in a two-patch environment. We assume the Volterra within-patch dynamics and provide a sufficient and necessary condition to guarantee the predator and prey species to be permanent by using the techniques of inequality analysis. Our work improves previous relevant results.

Xinyu Song

2004-09-01

217

Uniform exponential stability of linear periodic systems in a Banach space  

Directory of Open Access Journals (Sweden)

Full Text Available This article is devoted to the study of linear periodic dynamical systems, possessing the property of uniform exponential stability. It is proved that if the Cauchy operator of these systems possesses a certain compactness property, then the asymptotic stability implies the uniform exponential stability. We also show applications to different classes of linear evolution equations, such as ordinary linear differential equations in the space of Banach, retarded and neutral functional differential equations, some classes of evolution partial differential equations.

David N. Cheban

2001-01-01

218

Nonperturbative analysis of a model quantum system under time periodic forcing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We analyze the time evolution of a one-dimensional quantum system with an attractive delta function potential whose strength is subjected to a time periodic (zero mean) parametric variation. We show that for generic forcing which includes the sum of any finite number of harmonics, the system, started in a bound state will get fully ionized for large t irrespective of the magnitude or frequency of the forcing. There are however exceptional, very non-generic forcings that do n...

Costin, O.; Costin, R. D.; Lebowitz, A. Rokhlenko J.

2006-01-01

219

Orbital periods and Accretion disc structure of four AM CVn systems  

CERN Document Server

Phase-resolved spectroscopy of four AM CVn systems obtained with the William Herschel Telescope and the Gran Telescopio de Canarias (GTC) is presented. SDSS\\,J120841.96+355025.2 was found to have an orbital period of 52.96$\\pm$0.40\\,min and shows the presence of a second bright spot in the accretion disc. The average spectrum contains strong Mg\\,{\\sc i} and Si\\,{\\sc i/ii} absorption lines most likely originating in the atmosphere of the accreting white dwarf. SDSS\\,J012940.05+384210.4 has an orbital period of 37.555$\\pm$0.003 min. The average spectrum shows the Stark broadened absorption lines of the DB white dwarf accretor. The orbital period is close to the previously reported superhump period of 37.9\\,min. Combined, this results in a period excess $\\epsilon$=0.0092$\\pm$0.0054 and a mass ratio $q=0.031\\pm$0.018. SDSS\\,J164228.06+193410.0 displays an orbital period of 54.20$\\pm$1.60\\,min with an alias at 56.35\\,min. The average spectrum also shows strong Mg\\,{\\sc i} absorption lines, similar to SDSS\\,J120841...

Kupfer, T; Levitan, D; Steeghs, D; Marsh, T R; Rutten, R G M; Nelemans, G

2013-01-01

220

Orbital periods of cataclysmic variables identified by the SDSS. VII. Four new eclipsing systems  

CERN Document Server

We present photometry of nine cataclysmic variable stars identified by the Sloan Digital Sky Survey, aimed at measuring the orbital periods of these systems. Four of these objects show deep eclipses, from which we measure their orbital periods. The light curves of three of the eclipsing systems are also analysed using the LCURVE code, and their mass ratios and orbital inclinations determined. SDSS J075059.97+141150.1 has an orbital period of 134.1564 +/- 0.0008 min, making it a useful object with which to investigate the evolutionary processes of cataclysmic variables. SDSS J092444.48+080150.9 has a period of 131.2432 +/- 0.0014 min and is probably magnetic. The white dwarf ingress and egress phases are very deep and short, and there is no clear evidence that this object has an accretion disc. SDSS J115207.00+404947.8 and SDSS J152419.33+220920.1 are nearly identical twins, with periods of 97.5 +/- 0.4 and 93.6 +/- 0.5 min and mass ratios of 0.14 +/- 0.03 and 0.17 +/- 0.03, respectively. Their eclipses have w...

Southworth, John; Gansicke, B T; Pyrzas, S

2009-01-01

 
 
 
 
221

IEEE standard criteria for the periodic testing of nuclear power generating station safety systems  

International Nuclear Information System (INIS)

This standard provides criteria and requirements for the development of periodic testing programs for protection and power systems in commercial nuclear power generating stations. Development of these criteria and requirements is based on the prerequisite that the protection and power systems are testable and on the following: (1) Station protection systems and Class 1E power systems must, during the life of the station, be repeatedly tested to assess the operational availability of the systems. (2) Development and application of testing procedures and equipment must be consistent with safety system criteria IEEE Std 603-1977, protection system criteria IEEE Std 279-1971, and Class 1E power system criteria IEEE Std 308-1974. (3) Procedures for verification and documentation of failures should be such that reliability confidence levels are enhanced. The Institute of Electrical and Electronics Engineers has developed these proposed criteria to provide guidance in the development of the procedures and equipment for, and documentation of, periodic testing of nuclear power generating station protection and power systems. Each applicant for a construction permit or an operating license for a nuclear facility is required to develop these items to comply with the Atomic Energy Commission's Code of Federal Regulations, Part 50

222

Continuous time random walks in periodic systems: fluid limit and fractional differential equations on the circle  

Energy Technology Data Exchange (ETDEWEB)

In this paper, the continuous time random walk on the circle is studied. We derive the corresponding generalized master equation and discuss the effects of topology, especially important when Levy flights are allowed. Then, we work out the fluid limit equation, formulated in terms of the periodic version of the fractional Riemann-Liouville operators, for which we provide explicit expressions. Finally, we compute the propagator in some simple cases. The analysis presented herein should be relevant when investigating anomalous transport phenomena in systems with periodic dimensions.

Calvo, I [Laboratorio Nacional de Fusion, Asociacion EURATOM-CIEMAT, E-28040 Madrid (Spain); Carreras, B A [BACV Solutions Inc., Oak Ridge, TN 37830 (United States); Sanchez, R [Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Milligen, B Ph van [Laboratorio Nacional de Fusion, Asociacion EURATOM-CIEMAT, E-28040 Madrid (Spain)

2007-11-09

223

Continuous Time Random Walks in periodic systems: fluid limit and fractional differential equations on the circle  

Energy Technology Data Exchange (ETDEWEB)

In this article, the continuous time random walk on the circle is studied. We derive the corresponding generalized master equation and discuss the effects of topology, especially important when Levy flights are allowed. Then, we work out the fluid limit equation, formulated in terms of the periodic version of the fractional Riemann-Liouville operators, for which we provide explicit expressions. Finally, we compute the propagator in some simple cases. The analysis presented herein should be relevant when investigating anomalous transport phenomena in systems with periodic dimensions.

Calvo, Ivan [CIEMAT, Madrid; Carreras, Benjamin A [ORNL; Sanchez, Raul [ORNL; van Milligen, B. Ph. [Asociacion EURATOM-CIEMAT

2007-01-01

224

Periodic solutions for a class of non-coercive Hamiltonian systems  

Directory of Open Access Journals (Sweden)

Full Text Available We prove the existence of non-constant $T$-periodic orbits of the Hamiltonian system $$displaylines{ dot q =H_p (t, p(t, q(tcr dot p =-H_q (t, p(t, q(t, }$$ where $H$ is a $T$-periodic function in $t$, non-convex and non-coercive in $(p,q$, and has the form $H(t,p,qsim |q|^{alpha}(|p|^{Beta}-1$ with $alpha>Beta>1$.

Morched Boughariou

2001-05-01

225

Integrated characterization of multilayer periodic systems with nanosized layers as applied to Mo/Si structures  

Science.gov (United States)

The potential inherent in integrated characterization of multilayer periodic systems employed in development of extreme-ultraviolet mirrors was demonstrated using the example of Mo/Si structures grown by magnetron sputtering in different technological regimes. An integrated study provided mutually consistent data on the thicknesses and crystal structure of the layers, as well as on the quality of the interfaces. Measurements by atomic force microscopy permitted a comparison of surface roughness of the substrates and the multilayer systems grown on them. An analysis of the power spectral density functions revealed that low-frequency roughness is replicated from the substrate, whereas the high-frequency one can become smoothed out in the course of growth. X-ray diffractometry performed in the thin film mode showed that the Mo layers in the samples studied have different crystal structures, from the amorphous and polycrystalline to the [110]-textured one. An analysis of the transmission electron microscopy data confirmed that there is a difference in the degrees of crystallinity of Mo layers. The thicknesses of individual layers, the period, and the irreproducibility of the thicknesses and the period were determined using X-ray reflectometry. The root-mean-square roughness amplitude of the interfaces was estimated, and the existence of transition layers originating primarily from the Si layer was demonstrated. The study was used to formulate a proper strategy for the analysis of multilayer periodic systems with nanosized layers.

Valkovskiy, G. A.; Baidakova, M. V.; Brunkov, P. N.; Konnikov, S. G.; Sitnikova, A. A.; Yagovkina, M. A.; Zadiranov, Yu. M.

2013-03-01

226

Regulating Critical Period Plasticity: Insight from the Visual System to Fear Circuitry for Therapeutic Interventions  

Directory of Open Access Journals (Sweden)

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.

HirofumiMorishita

2013-11-01

227

Extended Horizon Liftings for Periodic Gain Adjustments in Control Systems, and for Equalization of Communication Channels  

Science.gov (United States)

Periodic gain adjustment in plants of irreducible order, n, or for equalization of communications channels is effected in such a way that the plant (system) appears to be minimum phase by choosing a horizon time N greater then n of liftings in periodic input and output windows Pu and Py, respectively, where N is an integer chosen to define the extent (length) of each of the windows Pu and Py, and n is the order of an irreducible input/output plant. The plant may be an electrical, mechanical or chemical system, in which case output tracking (OT) is carried out for feedback control or a communication channel, in which case input tracking (IT) is carried out. Conditions for OT are distinct from IT in terms of zero annihilation, namely for OT and of IT, where the OT conditions are intended for gain adjustments in the control system, and IT conditions are intended for equalization for communication channels.

Bayard, David S. (Inventor)

1996-01-01

228

Evolution of a model quantum system under time periodic forcing: conditions for complete ionization  

International Nuclear Information System (INIS)

We analyze the time evolution of a one-dimensional quantum system with an attractive delta function potential whose strength is subjected to a time periodic (zero mean) parametric variation ?(t). We show that for generic ?(t), which includes the sum of any finite number of harmonics, the system, started in a bound state will get fully ionized as t??. This is irrespective of the magnitude or frequency (resonant or not) of ?(t). There are however exceptional, very non-generic ?(t), that do not lead to full ionization, which include rather simple explicit periodic functions. For these ?(t) the system evolves to a nontrivial localized stationary state which is related to eigenfunctions of the Floquet operator. (orig.)

229

Periodic and chaotic synchronizations of two distinct dynamical systems under sinusoidal constraints  

International Nuclear Information System (INIS)

Highlights: ? Function synchronization of distinct dynamical systems. ? Synchronization onset and vanishing. ? Invariant sets of synchronization. ? Discontinuous dynamical systems. ? Synchronizations of pendulum and Duffing oscillator. - Abstract: In this paper, periodic and chaotic synchronizations between two distinct dynamical systems under specific constraints are investigated from the theory of discontinuous dynamical systems. The analytical conditions for the sinusoidal synchronization of the pendulum and Duffing oscillator were obtained, and the invariant domain of sinusoidal synchronization is achieved. From analytical conditions, the control parameter map is developed. Numerical illustrations for partial and full sinusoidal synchronizations of chaotic and periodic motions of the controlled pendulum with the Duffing oscillator are carried out. This paper presents how to apply the theory of discontinuous dynamical systems to dynamical system synchronization with specific constraints. The function synchronization of two distinct dynamical systems with specific constraints should be identified only by G-functions. The significance of function synchronization of distinct dynamical systems is to make the synchronicity behaviors hidden, which is very useful for telecommunication synchronization and network security.

230

Uniform exponential stability of linear almost periodic systems in Banach spaces  

Directory of Open Access Journals (Sweden)

Full Text Available This article is devoted to the study linear non-autonomous dynamical systems possessing the property of uniform exponential stability. We prove that if the Cauchy operator of these systems possesses a certain compactness property, then the uniform asymptotic stability implies the uniform exponential stability. For recurrent (almost periodic systems this result is precised. We also show application for different classes of linear evolution equations: ordinary linear differential equations in a Banach space, retarded and neutral functional differential equations, and some classes of evolution partial differential equations.

David N. Cheban

2000-04-01

231

Methods for estimation of radioactive iodine localization in post-accidental period using sprinkler systems  

International Nuclear Information System (INIS)

A technique for estimation of radioactive iodine localization in NPP room air in post-accidental period using sprinkler systems is described. Analysis for radioactive iodine by means of sprinkler systems is performed for I2 as a representative of the group of inorganic compounds and CH3I as a representative of the group of organic compounds. The calculations show that the elimination coefficient for aerosol and elementary components changes slightly during the sprinkler system operation while for the organic component CH3I it decreases two times, at that the largest drop is observed during the first hour when temperature decreases to 60 deg

232

Positive almost periodic solutions for state-dependent delay Lotka-Volterra competition systems  

Directory of Open Access Journals (Sweden)

Full Text Available In this article, using Mawhin's continuation theorem of coincidence degree theory, we obtain sufficient conditions for the existence of positive almost periodic solutions for the system of equations $$ dot{u}_i(t=u_i(tBig[r_i(t-a_{ii}(tu_i(t -sum_{j=1, jeq i}^na_{ij}(tu_jig(t-au_j(t,u_1(t, dots,u_n(tigBig], $$ where $r_i,a_{ii}>0$, $a_{ij}geq0(jeq i$, $i,j=1,2,dots,n$ are almost periodic functions, $au_iin C(mathbb{R}^{n+1},mathbb{R}$, and $au_i(i=1,2,dots,n$ are almost periodic in $t$ uniformly for $(u_1,dots,u_n^Tinmathbb{R}^n$. An example and its simulation figure illustrate our results.

Yongkun Li

2012-06-01

233

Globally and locally attractive solutions for quasi-periodically forced systems  

CERN Document Server

We consider a class of differential equations, $\\ddot x + \\gamma \\dot x + g(x) = f(\\omega t)$, with $\\omega \\in {\\bf R}^{d}$, describing one-dimensional dissipative systems subject to a periodic or quasi-periodic (Diophantine) forcing. We study existence and properties of the limit cycle described by the trajectory with the same quasi-periodicity as the forcing. For $g(x)=x^{2p+1}$, $p\\in {\\bf N}$, we show that, when the dissipation coefficient is large enough, there is only one limit cycle and that it is a global attractor. In the case of other forces, including $g(x)=x^{2p}$ (with $p=1$ describing the varactor equation), we find estimates for the basin of attraction of the limit cycle.

Bartuccelli, M V; Gentile, G

2005-01-01

234

Periodic Trojan-type orbits in the earth-sun system  

Science.gov (United States)

Periodic orbits about the triangular equilibrium points are found for the planar restricted three-body problem using the earth-sun system. The maximum semimajor axis for tadpole orbits ranges from the infinitesimal orbit at 1.000 AU to the near-limiting orbit at 1.00285 AU. Horseshoe orbits are found for 1.0029 to 1.0080 AU, larger horseshoes being unstable because of close approaches to the earth. Using stability tests devised by Rabe (1961, 1962), the limit of stability for nonperiodic orbits is found to occur for maximum semimajor axes near 1.0020 AU. In addition, near-periodic tadpole orbits appear to be stable against perturbations by Jupiter and Venus for periods of at least 10,000 yr. The possibility that minor planets actually exist in such orbits is considered.

Weissman, P. R.; Wetherill, G. W.

1974-01-01

235

Pattern Formation in Liquid-Vapor Systems under Periodic Potential and Shear  

CERN Document Server

In this paper the phase behavior and pattern formation in a sheared non-ideal fluid under a periodic potential is studied. An isothermal two-dimensional formulation of a lattice Boltzmann scheme for a liquid-vapor system with the van der Waals equation of state is presented and validated. Shear is applied by moving walls and the periodic potential will vary along the flow direction. A region of the parameter space, where in absence of flow a striped phase with oscillating density is stable, will be considered. At low shear rates the periodic patterns are preserved and slightly distorted by the flow. At high shear rates the striped phase looses its stability and a new phase with interface waves between the liquid and vapor regions will appear. Velocity field patterns will be also shown.

Coclite, Alessandro; Lamura, Antonio

2013-01-01

236

An Adaptive Control Scheme for Recovering Periodic Motion of Chaotic Systems  

Science.gov (United States)

The paper presents an adaptive control scheme for recovering the original dynamics of a nonlinear system after a sudden disturbance in a system parameter by controlling the system parameter through linear feedback. The key problem is to choose the control stiffness in the feedback by assigning the poles of the linearized controlled system in an extended state space, which consists of the system state and the system parameter. The paper gives the simulations of recovering the fixed point of the logistic map and the periodic orbit of a harmonically forced Duffing oscillator from the chaos due to a large disturbance in the parameter. The simulations demonstrate well the efficacy and the advantages of the proposed adaptive control scheme.

Hu, H. Y.

1997-01-01

237

The RR Lyrae Period-Luminosity-(Pseudo-)Color and Period-Color-(Pseudo-)Color Relations in the Str\\"omgren Photometric System: Theoretical Calibration  

CERN Document Server

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 ...

Cortés, C

2008-01-01

238

Periodic and quasi-periodic motions of a solar sail close to SL 1 in the Earth-Sun system  

Science.gov (United States)

Solar sails are a proposed form of spacecraft propulsion using large membrane mirrors to propel a satellite taking advantage of the solar radiation pressure. To model the dynamics of a solar sail we have considered the Earth-Sun Restricted Three Body Problem including the Solar radiation pressure (RTBPS). This model has a 2D surface of equilibrium points parametrised by the two angles that define the sail orientation. In this paper we study the non-linear dynamics close to an equilibrium point, with special interest in the bounded motion. We focus on the region of equilibria close to SL 1, a collinear equilibrium point that lies between the Earth and the Sun when the sail is perpendicular to the Sun-sail direction. For different fixed sail orientations we find families of planar, vertical and Halo-type orbits. We have also computed the centre manifold around different equilibria and used it to describe the quasi-periodic motion around them. We also show how the geometry of the phase space varies with the sail orientation. These kind of studies can be very useful for future mission applications.

Farrés, Ariadna; Jorba, Àngel

2010-06-01

239

A lack of short-period multiplanet systems with close-proximity pairs and the curious case of Kepler 42  

CERN Document Server

Many Kepler multiplanet systems have planet pairs near low-order, mean-motion resonances. In addition, many Kepler multiplanet systems have planets with orbital periods less than a few days. With the exception of Kepler-42, however, there are no examples of systems with both short orbital periods and nearby companion planets while our modeling predicts ~17 such pairs. For orbital periods of the inner planet that are less than three days, the minimum period ratio of adjacent planet pairs follows the rough constraint P_2/P_1 >~ 2.3 (P_1/day)^(-2/3). This excess is not due to a lack of planets with short orbital periods. We also show a statistically significant excess of small, single candidate systems with orbital periods below 3 days over the number of multiple candidate systems with similar periods---perhaps a small-planet counterpart to the hot Jupiters.

Steffen, Jason H

2013-01-01

240

BeppoSAX observations of the long period polar system V1309 Ori  

CERN Document Server

We present BeppoSAX observations of the peculiar long period polar system V1309 Ori (RXJ0515.6+0105). The source was detected simultaneously at soft and, for the first time, at hard X-rays with the LECS and the MECS detectors. Both, the LECS and the MECS light curves are irregular with a bursting/flaring type behaviour indicating inhomogeneous accretion onto the white dwarf. This peculiar variability, together with an extreme high soft-to-hard X-ray luminosity ratio, indicates that in V1309 Ori accretion occurs predominantly in highly compressed chunks or ``blobs'' of matter. From coordinated ESO optical spectroscopy, we find indications that the magnetic field strength of the white dwarf is < 70 MG, not expected either from the 8 hr orbital period synchronism or from the strong soft-to-hard X-ray ratio suggesting alternative solutions for sustaining synchronism in this system.

De Martino, D; Matt, G; Mouchet, M; Belloni, T; Beuermann, K; Chiappetti, L; Done, C; Gänsicke, B T; La Franca, F; Mukai, K

1998-01-01

 
 
 
 
241

Reverse resonance in stock prices of financial system with periodic information.  

Science.gov (United States)

We investigate the stochastic resonance of the stock prices in a finance system with the Heston model. The extrinsic and intrinsic periodic information are introduced into the stochastic differential equations of the Heston model for stock price by focusing on the signal power amplification (SPA). We find that for both cases of extrinsic and intrinsic periodic information a phenomenon of reverse resonance emerges in the behaviors of SPA as a function of the system and external driving parameters. Moreover, in both cases, a phenomenon of double reverse resonance is observed in the behavior of SPA versus the amplitude of volatility fluctuations, by increasing the cross correlation between the noise sources in the Heston model. PMID:23944522

Li, Jiang-Cheng; Mei, Dong-Cheng

2013-07-01

242

Reverse resonance in stock prices of financial system with periodic information  

Science.gov (United States)

We investigate the stochastic resonance of the stock prices in a finance system with the Heston model. The extrinsic and intrinsic periodic information are introduced into the stochastic differential equations of the Heston model for stock price by focusing on the signal power amplification (SPA). We find that for both cases of extrinsic and intrinsic periodic information a phenomenon of reverse resonance emerges in the behaviors of SPA as a function of the system and external driving parameters. Moreover, in both cases, a phenomenon of double reverse resonance is observed in the behavior of SPA versus the amplitude of volatility fluctuations, by increasing the cross correlation between the noise sources in the Heston model.

Li, Jiang-Cheng; Mei, Dong-Cheng

2013-07-01

243

Periodic-orbit theory of the number variance ?2(L) of strongly chaotic systems  

International Nuclear Information System (INIS)

We discuss the number variance ?2(L) and the spectral form factor F(?) of the energy levels of bound quantum systems whose classical counterparts are strongly chaotic. Exact periodic-orbit representations of ?2(L) and F(?) 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(?) to the commonly used approximation K(?) 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.)

244

Stability of Closed Loop Controlled Repetitive Periodic System applied to control of CD-Player  

DEFF Research Database (Denmark)

In this paper a criterion for stability of specific control scheme for handling linear dynamic control systems with repetitive periodic sensor faults is derived. The given system and control scheme are described and defined. By combining these with the lifting technique a necessary and sufficient stability criterion is derived. This criterion is following applied to an example on a feature based control scheme for handling CD-players playing CDs with surface faults. This feature based control scheme is handling repetitive periodic sensor faults. The feature based control scheme approximates the repetitive sensor faults (surface faults). The fault approximations are subsequently subtracted from the measurements, and the influence from these repetitive sensor faults are thereby removed from the computed control signals.

Odgaard, Peter Fogh; Stoustrup, Jakob

2005-01-01

245

Performance of Thomas-Fermi and linear response approaches in periodic two-dimensional systems  

Energy Technology Data Exchange (ETDEWEB)

A study of the performance of Thomas-Fermi and linear response theories in the case of a two-dimensional periodic model system is presented. The calculated density distribution and total energy per unit cell compare very well with exact results except when there is a small number of particles per cell, even though the potential has narrow tight-binding bands. The results supplement earlier findings of Koivisto and Stott for a localized impurity in a two-dimensional uniform gas.

Calderin, L; Stott, M J [Department of Physics, Queen' s University, Kingston, Ontario, K7 L 3N6 (Canada)], E-mail: calderin@physics.queensu.ca, E-mail: stott@mjs.phy.queensu.ca

2010-04-16

246

Notes on Multiple Periodic Solutions for Second-order Discrete Hamiltonian System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

By a new orthogonal direct sum decomposition $E_{M} = Y \\oplus Z$, which $Z$ is related to $\\Delta u_i(i=1,2,3,....,M)$, and a new functional $I(u)$, the method in [2] is improved to obtain new multiple periodic solutions with negativity hypothesis on $F$ for a second-order discrete Hamiltonian system. Moreover, we exhibit an instructive example to make our result more clear, which hasn't been solved by the known results.

Ding, Liang; Wei, Jinlong

2014-01-01

247

Density functional theory in periodic systems using local Gaussian basis sets  

Science.gov (United States)

This paper describes a new implementation of density functional theory for periodic systems in a basis of local Gaussian functions, including a thorough discussion of the various algorithms. The results of test calculations using this scheme are reported for some representative crystalline solids, with particular emphasis placed on the influence of the various computational parameters used to control the accuracy of the numerical integration of the exchange-correlation potential.

Towler, Michael D.; Zupan, Ales; Causà, Mauro

1996-10-01

248

Phase velocity and phase diffusion in periodically driven discrete state systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We develop a theory to calculate the effective phase diffusion coefficient and the mean phase velocity in periodically driven stochastic models with two discrete states. This theory is applied to a dichotomically driven Markovian two state system. Explicit expressions for the mean phase velocity, the effective phase diffusion coefficient and the P\\'eclet number are analytically calculated. The latter shows as a measure of phase-coherence forced synchronization of the stochas...

Prager, T.; Schimansky-geier, L.

2005-01-01

249

Renal tubular dysfunction presenting as recurrent hypokalemic periodic quadriparesis in systemic lupus erythematosus  

Science.gov (United States)

We report recurrent hypokalemic periodic quadriparesis in a 30-year-old woman. Patient had also symptoms of multiple large and small joint pain, recurrent oral ulceration, photosensitivity and hair loss that were persisting since last 6 months and investigations revealed systemic lupus erythematosus (SLE) with distal tubular acidosis. Our patient was successfully treated with oral potassium chloride, sodium bicarbonate, hydroxychloroquine and a short course of steroids. Thus, tubular dysfunction should be carefully assessed in patients with SLE.

Prasad, D.; Agarwal, D.; Malhotra, V.; Beniwal, P.

2014-01-01

250

A low-dimensional model system for quasi-periodic plasma perturbations  

International Nuclear Information System (INIS)

Larger scale plasma instabilities not leading to an immediate termination of a discharge often result in periodic nonlinear perturbations of the plasma. A minimal possible model is formulated for description of the system with drive and relaxation processes which have different time scales. The model is based on two equations: the first being responsible for the relaxation dynamics and the second for the drive. The model can be generalized to describe the pellet injection.

251

Radiation Detection by Employing Periodic Packets in Power-Line Communication System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The interference with existing radio broadcasting services because of unintentional radiation is a serious problem in power-line communication (PLC) systems. A radiation detection method based on burst packets, which had been proposed by the authors and was called scan and sum (SAS) method, was a low cost method and used to solve the problem. But its measurement took a long time and the burst packets occupied a channel. To shorten the measurement time, a new method based on period...

Areni, Intan Sari

2014-01-01

252

THE HD 192263 SYSTEM: PLANETARY ORBITAL PERIOD AND STELLAR VARIABILITY DISENTANGLED  

Energy Technology Data Exchange (ETDEWEB)

As part of the Transit Ephemeris Refinement and Monitoring Survey, we present new radial velocities and photometry of the HD 192263 system. Our analysis of the already available Keck-HIRES and CORALIE radial velocity measurements together with the five new Keck measurements we report in this paper results in improved orbital parameters for the system. We derive constraints on the size and phase location of the transit window for HD 192263b, a Jupiter-mass planet with a period of 24.3587 {+-} 0.0022 days. We use 10 years of Automated Photoelectric Telescope photometry to analyze the stellar variability and search for planetary transits. We find continuing evidence of spot activity with periods near 23.4 days. The shape of the corresponding photometric variations changes over time, giving rise to not one but several Fourier peaks near this value. However, none of these frequencies coincides with the planet's orbital period and thus we find no evidence of star-planet interactions in the system. We attribute the {approx}23 day variability to stellar rotation. There are also indications of spot variations on longer (8 years) timescales. Finally, we use the photometric data to exclude transits for a planet with the predicted radius of 1.09 R{sub J} , and as small as 0.79 R{sub J} .

Dragomir, Diana; Matthews, Jaymie M. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T1Z1 (Canada); Kane, Stephen R.; Ciardi, David R.; Von Braun, Kaspar [NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Henry, Gregory W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box 9501, Nashville, TN 37209 (United States); Fischer, Debra A. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Howard, Andrew W. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Jensen, Eric L. N. [Department of Physics and Astronomy, Swarthmore College, Swarthmore, PA 19081 (United States); Laughlin, Gregory [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Mahadevan, Suvrath; Pilyavsky, Genady; Wang, Sharon X.; Wright, Jason T., E-mail: diana@phas.ubc.ca [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

2012-07-20

253

On stability zones for discrete-time periodic linear Hamiltonian systems  

Directory of Open Access Journals (Sweden)

Full Text Available The main purpose of the paper is to give discrete-time counterpart for some strong (robust stability results concerning periodic linear Hamiltonian systems. In the continuous-time version, these results go back to Liapunov and ?ukovskii; their deep generalizations are due to Kre?n, Gel'fand, and Jakubovi? and obtaining the discrete version is not an easy task since not all results migrate mutatis-mutandis from continuous time to discrete time, that is, from ordinary differential to difference equations. Throughout the paper, the theory of the stability zones is performed for scalar (2nd-order canonical systems. Using the characteristic function, the study of the stability zones is made in connection with the characteristic numbers of the periodic and skew-periodic boundary value problems for the canonical system. The multiplier motion ("traffic" on the unit circle of the complex plane is analyzed and, in the same context, the Liapunov estimate for the central zone is given in the discrete-time case.

R?svan Vladimir

2006-01-01

254

On stability zones for discrete-time periodic linear Hamiltonian systems  

Directory of Open Access Journals (Sweden)

Full Text Available The main purpose of the paper is to give discrete-time counterpart for some strong (robust stability results concerning periodic linear Hamiltonian systems. In the continuous-time version, these results go back to Liapunov and ?ukovskii; their deep generalizations are due to Kre?n, Gel'fand, and Jakubovi? and obtaining the discrete version is not an easy task since not all results migrate mutatis-mutandis from continuous time to discrete time, that is, from ordinary differential to difference equations. Throughout the paper, the theory of the stability zones is performed for scalar (2nd-order canonical systems. Using the characteristic function, the study of the stability zones is made in connection with the characteristic numbers of the periodic and skew-periodic boundary value problems for the canonical system. The multiplier motion (“traffic” on the unit circle of the complex plane is analyzed and, in the same context, the Liapunov estimate for the central zone is given in the discrete-time case.

2006-01-01

255

On the structure of the set of bifurcation points of periodic solutions for multiparameter Hamiltonian systems  

International Nuclear Information System (INIS)

This paper deals with periodic solutions of the Hamilton equation x-dot (t)=J?x H(x(t),?), where H element of C2,0(R2n×Rk,R) and ? element of Rk is a parameter. Theorems on global bifurcation of solutions with periods (2?)/j, j element of N, from a stationary point (x0,?0) element of R2n×Rk are proved. ?x2 H(x0,?0) can be singular. However, it is assumed that the local topological degree of ?xH(·, ?0) at x0 is nonzero. For systems satisfying ?xH(x0, ?) = 0 for all ? element of Rk it is shown that (global) bifurcation points of solutions with periods (2?)/j can be identified with zeros of appropriate continuous functions Fj:Rk?R. If, for all ? element of Rk, ?x2H(x0,?)=diag(A(?),B(?)), where A(?) and B(?) are (n × n)-matrices, then Fj can be defined by Fj(?) = det[A(?)B(?) ? 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, Toru?)

256

Gamma radiolysis of binary aqueous systems : bromate, periodate, permanganate and dichromate ions  

International Nuclear Information System (INIS)

Gamma radiolysis of neutral aqueous solutions of bromate, periodate, permanganate and dichromate ions both in pure as well as in the presence of various organic solutes, viz. formate, acetate, succinate and ethyl alcohol have been investigated over a wide range of reactant concentrations. It is observed that in each mixed system, the decomposition yield is higher than that in the pure system. Appropriate mechanisms are suggested for the radiolytic reactions on the basis of the observed yields and the participation of primary radiolytic products of water. (author)

257

Magnet power supply control system for CSRm super-long-period slow extraction  

International Nuclear Information System (INIS)

In order to realize the HIRFL-CSR super-long-period slow extraction, the distributed control system of the CSR main ring (CSRm) power supply is designed based on high-speed ethernet, with the controller of the power supply employing ARM + DSP architecture. The control cycle adopts multipart handling mechanism to solve the problem that the waveform data is too large to be stored in the controller. The control system has been tested in the HIRFL-CSR, and successfully conducted the carbon ion's ten-thousand-second slow extraction. (authors)

258

Periodic Density Modulation Effects on a Correlated two-dimensional Composite Fermion System  

CERN Document Server

We examine theoretically the effects caused by a periodic external potential on the correlated motion of a two-dimensional electron system under strong magnetic fields corresponding to a filling factor 1/2. To describe the resulting complex dynamics, we adopt a composite fermion approach and we determine in a two loop approximation the density-response function $K_{00}(\\bfq,\\omega)$ and the compressibility. We show explicitly that the long-wavelength limit of $K_{00}(\\bfq,\\omega)$ exhibits substantial anisotropic behavior induced by the modulation, and that the system tends to be incompressible in a direction orthogonal to the modulation as opposed to its response along the modulation.

Sakhi, S

2001-01-01

259

Ionization of Coulomb systems in $\\RR^3$ by time periodic forcings of arbitrary size  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We analyze the long time behavior of solutions of the Schr\\"odinger equation $i\\psi_t=(-\\Delta-b/r+V(t,x))\\psi$, $x\\in\\RR^3$, $r=|x|$, describing a Coulomb system subjected to a spatially compactly supported time periodic potential $V(t,x)=V(t+2\\pi/\\omega,x)$ with zero time average. We show that, for any $V(t,x)$ of the form $2\\Omega(r)\\sin (\\omega t-\\theta)$, with $\\Omega(r)$ nonzero on its support, Floquet bound states do not exist. This implies that the system ionizes, {\\...

Costin, O.; Lebowitz, J. L.; Tanveer, S.

2006-01-01

260

Evolution of a model quantum system under time periodic forcing: conditions for complete ionization  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We analyze the time evolution of a one-dimensional quantum system with an attractive delta function potential whose strength is subjected to a time periodic (zero mean) parametric variation $\\eta(t)$. We show that for generic $\\eta(t)$, which includes the sum of any finite number of harmonics, the system, started in a bound state will get fully ionized as $t\\to\\infty$. This is irrespective of the magnitude or frequency (resonant or not) of $\\eta(t)$. There are however except...

Costin, O.; Costin, R. D.; Lebowitz, J. L.; Rokhlenko, A.

2000-01-01

 
 
 
 
261

Accurate frequency domain measurement of the best linear time-invariant approximation of linear time-periodic systems including the quantification of the time-periodic distortions  

Science.gov (United States)

Time-periodic (TP) phenomena occurring, for instance, in wind turbines, helicopters, anisotropic shaft-bearing systems, and cardiovascular/respiratory systems, are often not addressed when classical frequency response function (FRF) measurements are performed. As the traditional FRF concept is based on the linear time-invariant (LTI) system theory, it is only approximately valid for systems with varying dynamics. Accordingly, the quantification of any deviation from this ideal LTI framework is more than welcome. The “measure of deviation” allows us to define the notion of the best LTI (BLTI) approximation, which yields the best - in mean square sense - LTI description of a linear time-periodic LTP system. By taking into consideration the TP effects, it is shown in this paper that the variability of the BLTI measurement can be reduced significantly compared with that of classical FRF estimators. From a single experiment, the proposed identification methods can handle (non-)linear time-periodic [(N)LTP] systems in open-loop with a quantification of (i) the noise and/or the NL distortions, (ii) the TP distortions and (iii) the transient (leakage) errors. Besides, a geometrical interpretation of the BLTI approximation is provided, leading to a framework called vector FRF analysis. The theory presented is supported by numerical simulations as well as real measurements mimicking the well-known mechanical Mathieu oscillator.

Louarroudi, E.; Pintelon, R.; Lataire, J.

2014-10-01

262

H Infinity Control of Magnetic Bearings to Ensure Both System and External Periodic Disturbance Robustness  

Science.gov (United States)

Both self-excited and forced disturbances often lead to severe rotor vibrations in a magnetic bearing systems with long slender shafts. This problem has been studied using the H-infinity method, and stability with good robustness can be achieved for the linearized model of a magnetic bearing when small transient disturbances are applied. In this paper, the H-infinity control method for self-excited and forced disturbances is first reviewed. It is then applied to the control of a magnetic bearing rotor system. In modelling the system, the shaft is first discretized into 18 finite elements and then three levels of condensation are applied. This leads to a system with three masses and three compliant elements which can be described by six state variable coordinates. Simulation of the resultant system design has been performed at speeds up to 10,000 rpm. Disturbances in terms of different initial displacements, initial impulses, and external periodic inputs have been imposed. The simulation results show that good stability can be achieved under these different transient disturbances using the proposed controller while at the same time reducing the sensitivity to external periodic disturbances.

Jiang, Yuhong; Zmood, R. B.

1996-01-01

263

Models for maintenance optimization: a study for repairable systems and finite time periods  

International Nuclear Information System (INIS)

The problem of selecting a suitable maintenance policy for repairable systems and for a finite time period is presented. Since the late seventies, examples of models assessing corrective and preventive maintenance policies over an equipment life cycle exist in the literature. However, there are not too many contributions regarding real implementation of these models in the industry, considering realistic timeframes and for repairable systems. Modeling this problem requires normally the representation of different corrective and/or preventive actions that could take place at different moments, driving the equipment to different states with different hazard rates. An approach to pattern the system under finite periods of time has been the utilization of semi-Markovian probabilistic models, allowing later a maintenance policy optimization using dynamic programming. These models are very flexible to represent a given system, but they are also complex and therefore very difficult to handle when the number of the system possible states increases. This paper explores the trade-off between flexibility and complexity of these models, and presents a comparison in terms of model data requirements versus potential benefits obtained with the model

264

Phased mission modelling of systems with maintenance-free operating periods using simulated Petri nets  

Energy Technology Data Exchange (ETDEWEB)

A common scenario in engineering is that of a system which operates throughout several sequential and distinct periods of time, during which the modes and consequences of failure differ from one another. This type of operation is known as a phased mission, and for the mission to be a success the system must successfully operate throughout all of the phases. Examples include a rocket launch and an aeroplane flight. Component or sub-system failures may occur at any time during the mission, yet not affect the system performance until the phase in which their condition is critical. This may mean that the transition from one phase to the next is a critical event that leads to phase and mission failure, with the root cause being a component failure in a previous phase. A series of phased missions with no maintenance may be considered as a maintenance-free operating period (MFOP). This paper describes the use of a Petri net (PN) to model the reliability of the MFOP and phased missions scenario. The model uses Monte-Carlo simulation to obtain its results, and due to the modelling power of PNs, can consider complexities such as component failure rate interdependencies and mission abandonment. The model operates three different types of PN which interact to provide the overall system reliability modelling. The model is demonstrated and validated by considering two simple examples that can be solved analytically.

Chew, S.P.; Dunnett, S.J. [Department of Aeronautical and Automotive Engineering, Loughborough University, Loughborough, Leics (United Kingdom); Andrews, J.D. [Department of Aeronautical and Automotive Engineering, Loughborough University, Loughborough, Leics (United Kingdom)], E-mail: j.d.andrews@lboro.ac.uk

2008-07-15

265

Phased mission modelling of systems with maintenance-free operating periods using simulated Petri nets  

International Nuclear Information System (INIS)

A common scenario in engineering is that of a system which operates throughout several sequential and distinct periods of time, during which the modes and consequences of failure differ from one another. This type of operation is known as a phased mission, and for the mission to be a success the system must successfully operate throughout all of the phases. Examples include a rocket launch and an aeroplane flight. Component or sub-system failures may occur at any time during the mission, yet not affect the system performance until the phase in which their condition is critical. This may mean that the transition from one phase to the next is a critical event that leads to phase and mission failure, with the root cause being a component failure in a previous phase. A series of phased missions with no maintenance may be considered as a maintenance-free operating period (MFOP). This paper describes the use of a Petri net (PN) to model the reliability of the MFOP and phased missions scenario. The model uses Monte-Carlo simulation to obtain its results, and due to the modelling power of PNs, can consider complexities such as component failure rate interdependencies and mission abandonment. The model operates three different types of PN which interact to provide the overall system reliability modelling. The model is demonstrated and validated by considering two simple examples that can be solved analytically

266

Theory of finite periodic systems - I: General expressions and various simple and illustrative examples  

International Nuclear Information System (INIS)

A comprehensive presentation of a new approach to finite periodic systems is given. The novel and general expressions obtained here, allow simple and precise calculations of various physical quantities characteristic of crystalline systems. Transmission amplitudes through n-cell multichannel quantum systems are rigorously derived. General expressions for several physical quantities are entirely expressed in terms of single-cell amplitudes and a new class of polynomials pN,n. Besides the general expressions, we study some superlattice properties as the band structure and its relation with the phase coherence phenomena, the level density and the Kronig-Penney model as its continuous espectrum limit. Bandstructure tailoring, optical multilayer systems, resonant energies and functions and channel-mixing effects in multichannel transport process are also analysed in the light of the new approach. (author)

267

Oliver Sacks in Mendeleev's Garden  

Science.gov (United States)

After returning to New York, Oliver Sacks sent to us a preprint of Uncle Tungsten, which we had the pleasure of perusing for a whole year before publication. After the events of September 11, 2001, my wife and I anxiously awaited word that he was all right. We were relieved—and honored—when in early December we received an autographed copy of Uncle Tungsten (3). We will always treasure Oliver Sacks’s book, his remarkable story of chemistry, and our friendship with him.

Marshall, James L.

2003-08-01

268

Kapitza-Landau time window for a periodically driven system with friction: a system-bath Hamiltonian approach  

Science.gov (United States)

We analyze microscopically the classical dynamics of a Brownian particle moving through a damping medium in a confined potential in the presence of random impulses due to the surrounding medium, which is further subjected to a space dependent, high-frequency time-periodic force (with frequency ?). By invoking a systematic separation of time scales using the inverse of driving frequency as the small parameter, starting from a time-dependent system-reservoir model, we derive an effective system-reservoir Hamiltonian (Heff) which does not include explicit time-dependence. Heff yields an effective Langevin description of the system governed by a time-independent effective potential. Here, we want to generalize Kapitza's treatment for handling time dependent system within the system-reservoir frame. This work may be relevant for trapping of a classical particle with friction by introducing an external rapid time periodic potential. In our present formulation, different species of particles envisage different minima associated with the effective potential, and this is reminiscent of the fact that the effective potential bears explicit information of those parameters that specify the particles. This aspect can be suitably exploited to segregate different species of Brownian particles (that were initially mixed) with the aid of an appropriate driving by a space-dependent periodic force.

Shit, Anindita; Chattopadhyay, Sudip; Chaudhuri, Jyotipratim Ray

2013-01-01

269

CRYSCOR: a program for the post-Hartree-Fock treatment of periodic systems.  

Science.gov (United States)

Cryscor is a periodic post-Hartree-Fock program based on local functions in direct space, i.e., Wannier functions and projected atomic orbitals. It uses atom centered Gaussians as basis functions. The Hartree-Fock reference, as well as symmetry information, is provided by the Crystal program. Cryscor presently features an efficient and parallel implementation of periodic local second order Møller-Plesset perturbation theory (MP2), which allows us to study 1D-, 2D- and 3D-periodic systems beyond 1000 basis functions per unit cell. Apart from the correlation energy also the MP2 density matrix, and from that the Compton profile, are available. Very recently, a new module for calculating excitonic band gaps at the uncorrelated Configuration-Interaction-Singles (CIS) level has been added. Other advancements include new extrapolation techniques for calculating surface adsorption on semi-infinite solids. In this paper the diverse features and recent advances of the present Cryscor version are illustrated by exemplary applications to various systems: the adsorption of an argon monolayer on the MgO (100) surface, the rolling energy of a boron nitride nanoscroll, the relative stability of different aluminosilicates, the inclusion energy of methane in methane-ice-clathrates, and the effect of electron correlation on charge and momentum density of ?-quartz. Furthermore, we present some first tentative CIS results for excitonic band gaps of simple 3D-crystals, and their dependence on the diffuseness of the basis set. PMID:22334044

Pisani, Cesare; Schütz, Martin; Casassa, Silvia; Usvyat, Denis; Maschio, Lorenzo; Lorenz, Marco; Erba, Alessandro

2012-06-01

270

Harmless delays in a discrete ratio-dependent periodic predator-prey system  

Directory of Open Access Journals (Sweden)

Full Text Available Verifiable criteria are established for the existence of positive periodic solutions and permanence of a delayed discrete periodic predator-prey model with Holling-type II functional response N1(k+1=N1(kexp⁡{b1(k−a1(kN1(k−[τ1]−α1(kN2(k/(N1(k+m(kN2(k} and N2(k+1=N2(kexp⁡{−b2(k+α2(kN1(k−[τ2]/(N1(k−[τ2]+m(kN2(k−[τ2]}. Our results show that the delays in the system are harmless for the existence of positive periodic solutions and permanence of the system. In particular our investigation confirms that if the death rate of the predator is rather small as well as the intrinsic growth rate of the prey is relatively large, then the species could coexist in the long run.

Wan-Tong Li

2006-06-01

271

Phase-shift inversion in oscillator systems with periodically switching couplings  

Science.gov (United States)

A system's response to external periodic changes can provide crucial information about its dynamical properties. We investigate the synchronization transition, an archetypical example of a dynamic phase transition, in the framework of such a temporal response. The Kuramoto model under periodically switching interactions has the same type of phase transition as the original mean-field model. Furthermore, we see that the signature of the synchronization transition appears in the relative delay of the order parameter with respect to the phase of oscillating interactions as well. Specifically, the phase shift becomes significantly larger as the system gets closer to the phase transition, so that the order parameter at the minimum interaction density can even be larger than that at the maximum interaction density, counterintuitively. We argue that this phase-shift inversion is caused by the diverging relaxation time, in a similar way to the resonance near the critical point in the kinetic Ising model. Our result, based on exhaustive simulations on globally coupled systems as well as scale-free networks, shows that an oscillator system's phase transition can be manifested in the temporal response to the topological dynamics of the underlying connection structure.

Lee, Sang Hoon; Lee, Sungmin; Son, Seung-Woo; Holme, Petter

2012-02-01

272

The critical period of reservoir systems considering performance indices on Malaysia rivers  

Directory of Open Access Journals (Sweden)

Full Text Available The behavior of reservoir systems can be investigated using Critical Period (CP which determines the aggregation level of the data (monthly or annual that are required to be utilized in the reservoir analysis. Currently there are a number of methods that could approximate the behavior of reservoir systems, however the efficiency of these approaches have not been studied and verified for the Malaysia Rivers. In this study two different hypothetical reservoirs on Malaysia Rivers are selected. The stream flow data are subjected to preliminary analysis and evaluation of the fittest probability distribution function. Afterwards, the CP is estimated by applying a Monte Carlo simulation technique and considering performance indices. The CP from this study is used to determine the within-year or over-year behavior and these results are compared with those of the previous well-known equations in this area. It is observed that existing equations are incomplete and other parameters such as reliability and vulnerability should be considered to predict the behavior of reservoir systems. Consequently two separate regression equations are proposed to estimate the CP of these reservoir systems in Malaysia and some suggestions are made to generalize and extend this study.   Keywords: Critical Period, Monte Carlo Simulation, Over-Year Behavior, Performance Indices, Reliability, Vulnerability, Within-Year Behavior. Normal 0 false false false EN-US X-NONE AR-SA

Issa Saket Oskoui

2014-03-01

273

Multiple Periodic Solutions for Some Classes of First-Order Hamiltonian Systems  

Directory of Open Access Journals (Sweden)

Full Text Available Considering a decomposition R2N=A?B of R2N , we prove in this work, the existence of at least (1+dimA geometrically distinct periodic solutions for the first-order Hamiltonian system Jx'(t+H'(t,x(t+e(t=0 when the Hamiltonian H(t,u+v is periodic in (t,u and its growth at infinity in v is at most like or faster than |v|a, 0?a<1 , and e is a forcing term. For the proof, we use the Least Action Principle and a Generalized Saddle Point Theorem.

Mohsen Timoumi

2011-07-01

274

1/1 resonant periodic orbits in three dimensional planetary systems  

CERN Document Server

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.

Antoniadou, Kyriaki I; Varvoglis, Harry

2014-01-01

275

Gap opening and split band edges in waveguides coupled by a periodic system of small windows  

CERN Document Server

At the example of two coupled waveguides we construct a periodic second order differential operator acting in a Euclidean domain and having spectral gaps whose edges are attained strictly inside the Brillouin zone. The waveguides are modeled by the Laplacian in two infinite strips of different width that have a common interior boundary. On this common boundary we impose the Neumann boundary condition but cut out a periodic system of small holes, while on the remaining exterior boundary we impose the Dirichlet boundary condition. It is shown that, by varying the widths of the strips and the distance between the holes, one can control the location of the extrema of the band functions as well as the number of the open gaps. We calculate the leading terms in the asymptotics for the gap lengths and the location of the extrema.

Borisov, D

2012-01-01

276

Sub-daily periodicities in the results of local monitoring using global navigation satellite systems  

Science.gov (United States)

Nowadays the more attention is focused on the continuous monitoring by using of global navigation satellite systems (GNSS) in the study and control of stability of engineering structures and natural objects. The diurnal and semi-diurnal oscillations take place in high frequency GNSS observation. These waves are caused by the presence of the high frequency periodicities in changes of all geospheres, but also in systematic errors of GNSS techniques. Thus the diurnal variations are already found in the coordinates of global and regional networks of CORS stations. They are often related with the influence of Earth's diurnal tides. The purpose of this study is to examine the periodic variations in coordinate increments of local monitoring networks of engineering structures and the earth's surface. But in this case the tidal changes have a small influence because of the relative proximity of the network control points. Results of static GNSS observations in the local network with the control vectors baselines from 170 m to 4.3 km of length were used for the analysis of periodicities. The hourly time series of baseline components of the length of two months were analyzed. Three qualitatively different methods were applied: wavelet transformation (Morlet wavelet function), fast Fourier transformation (FFT), and sequential analysis of the dominant harmonics (dominant analysis) for the more sure detection of hidden periodicities. The results of determination of oscillation spectrum were obtained by the three methods mentioned above. For all baselines their good mutual agreement were obtained. Diurnal and semi-diurnal waves are mainly and the most vividly appeared in the horizontal components, in the height’s component there are also other periodicity of the high and low frequencies. The oscillation’s amplitude reaches 4 mm. It is necessary to clarify the nature of the observed oscillations, which will be the main subject of the following more detailed studies. It is important, since the cause of the detected periodic oscillations can be the real changes, such as temperature deformation of engineering structures as well as the changes connected with the influence of systematic errors of GNSS measurements for example. The obtained results lead to the following conclusions. - In the results of GNSS geodynamic monitoring of engineering structures and objects on the earth surface the stable oscillatory components with periods of 1 and 0.5 days, and amplitudes up to 4 mm are found. - Further analysis of the reasons of identified oscillations that may be caused by the real change of monitored objects and as well as systematic errors of measurement GNSS is required.

Kaftan, Vladimir; Ustinov, Alexander

277

Spectral factorization in periodically time-varying systems and application to navigation problems.  

Science.gov (United States)

Spectral factorization has been used previously to derive the steady-state solution of Kalman filtering equations without iteration for constant coefficient systems. The present work extends the spectral factorization algorithm to time-varying systems having periodic coefficient matrices for cases of both discrete and continuous systems. Time-consuming, expensive iterations of sequential covariance equations are not required to reach the final solution since this is an algebraic algorithm employing existing eigenvalue, eigenvector subroutines. The computer program incorporating the algorithm is suitable for sensitivity studies in formulating navigation and guidance strategies of low-thrust interplanetary missions. The determination of an optimum tracking pattern from an earth station is examined as an example.

Nishimura, T.

1972-01-01

278

Quasigauge Spaces with Generalized Quasipseudodistances and Periodic Points of Dissipative Set-Valued Dynamic Systems  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract In quasigauge spaces, we introduce the families of generalized quasipseudodistances, and we define three kinds of dissipative set-valued dynamic systems with these families of generalized quasi-pseudodistances and with some families of not necessarily lower semicontinuous entropies and next, assuming that quasigauge spaces are left sequentially complete (but not necessarily Hausdorff, we prove that for each starting point each dynamic process or generalized sequence of iterations of these dissipative set-valued dynamic systems left converges and we also show that if an iterate of these dissipative set-valued dynamic systems is left quasiclosed, then these limit points are periodic points. Examples illustrating ideas, methods, definitions, and results are constructed.

W?odarczyk Kazimierz

2011-01-01

279

Resonance tongues and patterns in periodically forced reaction-diffusion systems  

CERN Document Server

Various resonant and near-resonant patterns form in a light-sensitive Belousov-Zhabotinsky (BZ) reaction in response to a spatially-homogeneous time-periodic perturbation with light. The regions (tongues) in the forcing frequency and forcing amplitude parameter plane where resonant patterns form are identified through analysis of the temporal response of the patterns. Resonant and near-resonant responses are distinguished. The unforced BZ reaction shows both spatially-uniform oscillations and rotating spiral waves, while the forced system shows patterns such as standing-wave labyrinths and rotating spiral waves. The patterns depend on the amplitude and frequency of the perturbation, and also on whether the system responds to the forcing near the uniform oscillation frequency or the spiral wave frequency. Numerical simulations of a forced FitzHugh-Nagumo reaction-diffusion model show both resonant and near-resonant patterns similar to the BZ chemical system.

Lin, A L; Meron, E; Swinney, H L; Lin, Anna L.; Hagberg, Aric; Meron, Ehud; Swinney, Harry L.

2004-01-01

280

Large-scale periodicity in the distribution of QSO absorption-line systems  

CERN Document Server

The spatial-temporal distribution of absorption-line systems (ALSs) observed in QSO spectra within the cosmological redshift interval z = 0.0--4.3 is investigated on the base of our updated catalog of absorption systems. We consider so called metallic systems including basically lines of heavy elements. The sample of the data displays regular variations (with amplitudes ~ 15 -- 20%) in the z-distribution of ALSs as well as in the eta-distribution, where eta is a dimensionless line-of-sight comoving distance, relatively to smoother dependences. The eta-distribution reveals the periodicity with period Delta eta = 0.036 +/- 0.002, which corresponds to a spatial characteristic scale (108 +/- 6) h(-1) Mpc or (alternatively) a temporal interval (350 +/- 20) h(-1) Myr for the LambdaCDM cosmological model. We discuss a possibility of a spatial interpretation of the results treating the pattern obtained as a trace of an order imprinted on the galaxy clustering in the early Universe.

Ryabinkov, A I; 10.1007/s10509-010-0448-1

2010-01-01

 
 
 
 
281

Soliton defects in one-gap periodic system and exotic supersymmetry  

CERN Document Server

By applying Darboux-Crum transformations to the quantum one-gap Lame system, we introduce an arbitrary countable number of bound states into forbidden bands. The perturbed potentials are reflectionless and contain two types of soliton defects in the periodic background. The bound states with finite number of nodes are supported in the lower forbidden band by the periodicity defects of the potential well type, while the pulse type bound states in the gap have infinite number of nodes and are trapped by defects of the compression modulations nature. We investigate the exotic nonlinear N=4 supersymmetric structure in such paired Schrodinger systems, which extends an ordinary N=2 supersymmetry and involves two bosonic generators composed from Lax-Novikov integrals of the subsystems. One of the bosonic integrals has a nature of a central charge, and allows us to liaise the obtained systems with the stationary equations of the Korteweg-de Vries and modified Korteweg-de Vries hierarchies. This exotic supersymmetry o...

Arancibia, Adrian; Jakubsky, Vit; Guilarte, Juan Mateos; Plyushchay, Mikhail S

2014-01-01

282

Extended horizon lifting for periodic gain adjustment in control systems, and for equalization of communication channels  

Science.gov (United States)

Periodic gain adjustment in plants of irreducible order, n, or for equalization of communications channels is effected in such a way that the plant (system) appears to be minimum phase by choosing a horizon time N is greater than n of liftings in periodic input and output windows rho sub u and rho sub y, respectively, where N is an integer chosen to define the extent (length) of each of the windows rho sub u and rho sub y, and n is the order of an irreducible input/output plant. The plant may be an electrical, mechanical, or chemical system, in which case output tracking (OT) is carried out for feedback control or a communication channel, in which case input tracking (IT) is performed. Conditions for OT are distinct from IT in terms of zero annihilation, namely H(sub s)H(sub s)(sup +) = I for OT and H(sub s)H(sub s)(sup +) = I of IT, where the OT conditions are intended for gain adjustments in the control system, and IT conditions are intended for equalization for communication channels.

Bayard, David S. (inventor)

1994-01-01

283

Effect of periodic surface cracks on the interfacial fracture of thermal barrier coating system  

Science.gov (United States)

Periodic surface cracks and interfacial debonding in thermal barrier coating (TBC) system may be induced during cooling process. The objective of this work is to investigate the effect of periodic surface cracks on the interfacial fracture of TBC system. The finite element method (FEM) incorporating cohesive zone model is used in analysis. It is found that surface crack spacing has significant effect on the initiation and propagation of short interface crack. Three different regions are identified for describing the effect of surface crack spacing. In Region I the interface crack driving force is dramatically reduced due to high surface crack density. In this case, the initiation of interfacial delamination can be delayed. Region II applies as the surface crack spacing is moderate. Analysis of this transition zone brings to the definition of normalized critical surface crack spacing. Region III arises for sufficient large surface crack spacing. In this case, the interface crack driving force reaches a steady state, where the effects of adjacent surface cracks are relatively insignificant and can be ignored. It can be concluded that an appropriately high surface crack density can enhance the durability of TBC system.

Fan, X. L.; Xu, R.; Zhang, W. X.; Wang, T. J.

2012-10-01

284

Design of tapered arm impulse radiating antenna with log periodic lens system for skin cancer treatment.  

Science.gov (United States)

A Prolate-Spheroidal Impulse Radiating Antenna (PSIRA) is used as a non-invasive technique for generating an electromagnetic implosion to kill melanoma cells. It can launch and focus fast (100?ps) high voltage (>50?KV) pulses into the biological targets. It can be used to obtain electromagnetic focusing on the target to reduce the damage to the tissue layers surrounding the target (skin). The main aim of this work is to improve the gain of the antenna, enhance the electric field intensity and to reduce the spot size at the focal point. In this work the PSIRA with tapered arm is designed to increase the gain of the antenna. The log periodic lens system is designed to enhance the electric field and reduce the spot size. The IRA with tapered arms located at the position of ??=?60° gives a gain improvement of 14.28% when compared to a traditional IRA. In this work a 10-layer dielectric lens system is designed to match the 100?ps pulses to the skin phantom. Simulation results show that the electric field is increased by a factor of 2. The spot size is reduced from 1?cm to 0.75?cm at the focal point where the target is placed. The proposed Log periodic lens system provides an increase in electric field amplitude and reduction in spot size. PMID:24548051

Petrishia, A; Sasikala, M

2014-04-01

285

Controlling activated processes of nonadiabatically, periodically driven dynamical systems: A multiple scale perturbation approach  

Science.gov (United States)

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 ?) 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/? to the order ?-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 ? on the resulting rate in conjunction with the thermal energy. With large value of ?, 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.

Shit, Anindita; Chattopadhyay, Sudip; Chaudhuri, Jyotipratim Ray

2012-06-01

286

Quantization and Fractional Quantization of Currents in Periodically Driven Stochastic Systems I: Average Currents  

CERN Document Server

This article studies Markovian stochastic motion of a particle on a graph with finite number of nodes and periodically time-dependent transition rates that satisfy the detailed balance condition at any time. We show that under general conditions, the currents in the system on average become quantized or fractionally quantized for adiabatic driving at sufficiently low temperature. We develop the quantitative theory of this quantization and interpret it in terms of topological invariants. By implementing the celebrated Kirchhoff theorem we derive a general and explicit formula for the average generated current that plays a role of an efficient tool for treating the current quantization effects.

Chernyak, Vladimir Y; Sinitsyn, Nikolai A

2011-01-01

287

Quantization and fractional quantization of currents in periodically driven stochastic systems. I. Average currents.  

Science.gov (United States)

This article studies Markovian stochastic motion of a particle on a graph with finite number of nodes and periodically time-dependent transition rates that satisfy the detailed balance condition at any time. We show that under general conditions, the currents in the system on average become quantized or fractionally quantized for adiabatic driving at sufficiently low temperature. We develop the quantitative theory of this quantization and interpret it in terms of topological invariants. By implementing the celebrated Kirchhoff theorem we derive a general and explicit formula for the average generated current that plays a role of an efficient tool for treating the current quantization effects. PMID:22519315

Chernyak, Vladimir Y; Klein, John R; Sinitsyn, Nikolai A

2012-04-21

288

Continuum bound states as surface states of a finite periodic system  

International Nuclear Information System (INIS)

We discuss the relation between continuum bound states (CBSs) localized on a defect, and surface states of a finite periodic system. We model an experiment of Capasso et al. [F. Capasso, C. Sirtori, J. Faist, D. L. Sivco, S-N. G. Chu, and A. Y. Cho, Nature (London) 358, 565 (1992)] using the transfer-matrix method. We compute the rate for intrasubband transitions from the ground state to the CBS and derive a sum rule. Finally we show how to improve the confinement of a CBS while keeping the energy fixed

289

Simulated annealing algorithm for finding periodic orbits of multi-electron atomic systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We adapt the simulated annealing algorithm to the search of periodic orbits for classical multi-electron atomic systems. This is done by minimizing the n-th return distance to the initial position on a Poincare surface of section under an energy constraint. Here we give evidence of the feasibility of the method by applying it to the helium atom in the ground state for one to three spatial dimensions. We examine the structure of the dynamics and connect its organization to th...

Mauger, Francois; Chandre, Cristel; Uzer, Turgay

2010-01-01

290

Triple scale analysis of periodic solutions and resonance of some asymmetric non linear vibrating systems  

CERN Document Server

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.

Rousselet, Bernard

2013-01-01

291

Instability of a periodic system in a case of internal resonance  

Science.gov (United States)

The stability of periodic motion is investigated for the critical case of n pairs of purely imaginary characteristic indices. It is shown that instability generally occurs under resonance conditions when the ratio of the modulus of one of the characteristic indices to the frequency of unperturbed motion is an integer. The result obtained is used for studying the self-oscillations of an autonomous quasi-linear system in the case where the Andronov-Witte criterion does not apply. The instability of the Froude pendulum at a bifurcation point is proved.

Kunitsyn, A. L.; Tashimov, L. T.

1986-12-01

292

Separation of suspended particles in microfluidic systems by directional locking in periodic fields  

Science.gov (United States)

We investigate the transport and separation of overdamped particles under the action of a uniform external force in a two-dimensional periodic energy landscape. Exact results are obtained for the deterministic transport in a square lattice of parabolic, repulsive centers that correspond to a piecewise-continuous linear-force model. The trajectories are periodic and commensurate with the obstacle lattice and exhibit phase-locking behavior in that the particle moves at the same average migration angle for a range of orientation of the external force. The migration angle as a function of the orientation of the external force has a Devil’s staircase structure. The first transition in the migration angle was analyzed in terms of a Poincare map, showing that it corresponds to a tangent bifurcation. Numerical results show that the limiting behavior for impenetrable obstacles is equivalent to the high Peclet number limit in the case of transport of particles in a periodic pattern of solid obstacles. Finally, we show how separation occurs in these systems depending on the properties of the particles.

Herrmann, John; Karweit, Michael; Drazer, German

2009-06-01

293

Rotation periods of Post-T Tauri stars in Lindroos systems  

CERN Document Server

We present a rotational study of Post-T Tauri stars (PTTSs) in Lindroos systems, defined as binaries with early type primaries on the main-sequence (MS) and late-type secondaries on the pre-main-sequence (PMS) phase. The importance of this study in comparison with previous ones is that the Lindroos sample is not X-ray selected so we avoid a possible bias towards fast rotators. In this preliminary study we have monitored eleven stars in the UBVRI bands during two campaigns of ten consecutive nights each. Eight of the observed PTTSs show periodic modulations in their lightcurves and the derived periods range from 1.9d to 8.0d. The comparison of these results with theoretical rotational tracks based on disk-star locking theory shows that star-disk decoupling times of 1-20 Myr could reproduce the rotational properties of the targets, assuming an initial rotation period of ~8d and a mass of 1 Mo. We have studied the rotation-activity relations of Lindroos PTTSs and compared them with those found in other groups of...

Huélamo, N; Neuhäuser, R; Wolk, S J

2004-01-01

294

Optimal sampling period of the digital control system for the nuclear power plant steam generator water level control  

International Nuclear Information System (INIS)

A great effort has been made to improve the nuclear plant control system by use of digital technologies and a long term schedule for the control system upgrade has been prepared with an aim to implementation in the next generation nuclear plants. In case of digital control system, it is important to decide the sampling period for analysis and design of the system, because the performance and the stability of a digital control system depend on the value of the sampling period of the digital control system. There is, however, currently no systematic method used universally for determining the sampling period of the digital control system. Generally, a traditional way to select the sampling frequency is to use 20 to 30 times the bandwidth of the analog control system which has the same system configuration and parameters as the digital one. In this paper, a new method to select the sampling period is suggested which takes into account of the performance as well as the stability of the digital control system. By use of the Irving's model steam generator, the optimal sampling period of an assumptive digital control system for steam generator level control is estimated and is actually verified in the digital control simulation system for Kori-2 nuclear power plant steam generator level control. Consequently, we conclude the optimal sampling period of the digital control system for Kori-2 nuclear power plant steam generator level control is 1 second for all power ranges. 7 figs., 3 tabs., 8 refs. (Author)

295

The Education System in East Jerusalem during the Period of Jordanian Rule, 1948-1967  

Directory of Open Access Journals (Sweden)

Full Text Available The article below deals with the Arab educational system in East Jerusalem during the period of Jordanian rule, 1948-1967. Its main aim is to examine the attempts and efforts of the Jordanian government promote a new sense of identity among the Palestinians residing in Jerusalem in order to strengthen their loyalty to the Hashemite regime that had annexed the West Bank and turned it into an inseparable part of the Kingdom of Jordan. The article shows how the educational system was inducted for the purpose of constructing this new identity through a comprehensive change in study programs and textbooks. However, in spite of this, these efforts failed and Palestinian identity was preserved and even strengthened. 

Mustafa Abbasi

2014-01-01

296

Quasi-periodic motions in families of dynamical systems order amidst chaos  

CERN Document Server

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.

Broer, Hendrik W; Sevryuk, Mikhail B

1996-01-01

297

Light and colour curve observations and analysis of the short period eclipsing binary system UV Psc  

International Nuclear Information System (INIS)

The author has presented and analysed B and V light curves and the (B - V)-colour curve of the short period (RS CVn type) binary system UV Psc, and derived absolute information from the available data. Chi2 minimization procedures were utilized to a large extent in fitting light and colour curves. The solutions show the binary to be at a distance of about 90 pc with two detached components which are close to the main sequence (G2 and K0). The inclination of the orbit is close to 900. Photometric irregularities present in the light curve are briefly considered in relation to current ideas on RS CVn systems, and the colour information indicates a locally hotter (rather than cooler) region is responsible for the irregularities. (Auth.)

298

Closed periodic orbits of convective solutions in rapidly rotating system: Double torus knots and links, DTK  

International Nuclear Information System (INIS)

The classification of closed periodic orbits of convection in a rapidly rotating system is given. It is shown that double torus knots and links, DTK, do occur, which is a very wide and important class of knots and links. We also proved that there is no double torus Lorenz knots, this answers question 6 raised by Hill and Murasugi in [Peter Hill, On double-torus knots 1. J Knot Theor Ramif 1999;8(8):1009-48]. It is also shown that the system produces torus knots and links, for some specific parameters. In fact this approach suggests the study of double torus knots and links through dynamical tools, such as symbolic dynamics and templates

299

IP Eridani: A surprising long-period binary system hosting a He white dwarf  

Science.gov (United States)

We determine the orbital elements for the K0 IV + white dwarf (WD) system IP Eri, which appears to have a surprisingly long period of 1071 d and a significant eccentricity of 0.25. Previous spectroscopic analyses of the WD, based on a distance of 101 pc inferred from its Hipparcos parallax, yielded a mass of only 0.43 M?, implying it to be a helium-core WD. The orbital properties of IP Eri are similar to those of the newly discovered long-period subdwarf B star (sdB) binaries, which involve stars with He-burning cores surrounded by extremely thin H envelopes, and are therefore close relatives to He WDs. We performed a spectroscopic analysis of high-resolution spectra from the HERMES/Mercator spectrograph and concluded that the atmospheric parameters of the K0 component are Teff = 4960 K, log g = 3.3, [Fe/H] = 0.09 and ? = 1.5 km s-1. The detailed abundance analysis focuses on C, N, O abundances, carbon isotopic ratio, light (Na, Mg, Al, Si, Ca, Ti) and s-process (Sr, Y, Zr, Ba, La, Ce, Nd) elements. We conclude that IP Eri abundances agree with those of normal field stars of the same metallicity. The long period and non-null eccentricity indicate that this system cannot be the end product of a common-envelope phase; it calls instead for another less catastrophic binary-evolution channel presented in detail in a companion paper. Appendix A is available in electronic form at http://www.aanda.orgHERMES spectra are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/567/A30

Merle, T.; Jorissen, A.; Masseron, T.; Van Eck, S.; Siess, L.; Van Winckel, H.

2014-07-01

300

Optimization of Water Circulation Period for the Culture of Goldfish with Spinach in Aquaponic System  

Directory of Open Access Journals (Sweden)

Full Text Available Experiment with varied water circulation periods having 4, 8, 12, and 24 hrs/day as T1, T2, T3 and T4, respectively in aquaponics, evaluated against a control (without aquaponics revealed higher fish and plant growth in T3 and T4. The mean growth of fish varied significantly among treatments showing higher growth in T4 and control followed by T3, T2 and T1. Survival rate was 100% in all the treatments as well as control. Percentage weight gain, SGR (% day-1 also showed the similar trend as that of growth showing T4 as better treatment immediately followed by T3 then T2 and T1. The system maintained favourable water quality throughout the experiment. The growth in T3 and T4 did not vary significantly and was higher than the T1, T2 and control. Also percentage length gain at the end of the trial was maximum in T3 and T4. The Chl (a+b content in the control was higher than all the treatments whereas, T4 showed the maximum concentration among treatments followed by T3, T2 and then T1. Comparison of all the growth attributes and water quality parameters indicated that water circulation can be reduced to 12 hrs/day for economically effective aquaponics and can be considered as optimum water circulation period for goldfish production in aquaponic system.

A. P. Shete

2013-03-01

 
 
 
 
301

Development of a Safety Assessment Information System for the Management of Periodic Safety Assessment Activities  

International Nuclear Information System (INIS)

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

302

BeppoSAX observations of the long period polar system V1309Ori  

Science.gov (United States)

We present BeppoSAX observations of the peculiar long period polar system V1309Ori (RXJ0515.6+0105). The source was detected simultaneously at soft and, for the first time, at hard X-rays with the LECS and the MECS detectors. Both, the LECS and the MECS light curves are irregular with a bursting/flaring type behaviour indicating inhomogeneous accretion onto the white dwarf. This peculiar variability, together with an extreme high soft-to-hard X-ray luminosity ratio, indicates that in V1309Ori accretion occurs predominantly in highly compressed chunks or ``blobs'' of matter. From coordinated ESO optical spectroscopy, we find indications that the magnetic field strength of the white dwarf is < 70MG, not expected either from the 8hr orbital period synchronism or from the strong soft-to-hard X-ray ratio suggesting alternative solutions for sustaining synchronism in this system. Also based on observations collected at the European Southern Observatory, La Silla, Chile

de Martino, D.; Barcaroli, R.; Matt, G.; Mouchet, M.; Belloni, T.; Beuermann, K.; Chiappetti, L.; Done, C.; Gänsicke, B. T.; La Franca, F.; Mukai, K.

1998-04-01

303

Dynamical-systems analysis and unstable periodic orbits in reacting flows behind symmetric bluff bodies  

Science.gov (United States)

Dynamical systems analysis is performed for reacting flows stabilized behind four symmetric bluff bodies to determine the effects of shape on the nature of flame stability, acoustic coupling, and vortex shedding. The task requires separation of regular, repeatable aspects of the flow from experimental noise and highly irregular, nonrepeatable small-scale structures caused primarily by viscous-mediated energy cascading. The experimental systems are invariant under a reflection, and symmetric vortex shedding is observed throughout the parameter range. As the equivalence ratio—and, hence, acoustic coupling—is reduced, a symmetry-breaking transition to von Karman vortices is initiated. Combining principal-components analysis with a symmetry-based filtering, we construct bifurcation diagrams for the onset and growth of von Karman vortices. We also compute Lyapunov exponents for each flame holder to help quantify the transitions. Furthermore, we outline changes in the phase-space orbits that accompany the onset of von Karman vortex shedding and compute unstable periodic orbits (UPOs) embedded in the complex flows prior to and following the bifurcation. For each flame holder, we find a single UPO in flows without von Karman vortices and a pair of UPOs in flows with von Karman vortices. These periodic orbits organize the dynamics of the flow and can be used to reduce or control flow irregularities. By subtracting them from the overall flow, we are able to deduce the nature of irregular facets of the flows.

Hua, Jia-Chen; Gunaratne, Gemunu H.; Kostka, Stanislav; Jiang, Naibo; Kiel, Barry V.; Gord, James R.; Roy, Sukesh

2013-09-01

304

On the Counteraction of Periodic Torques for Rotating Systems Using Centrifugally Driven Vibration Absorbers  

Science.gov (United States)

A class of mechanical systems is considered which rotate about a fixed axis and are subjected to applied, angle-periodic torques. Of interest here is the counteraction of these torques by means of centrifugally driven masses which move along prescribed paths relative to the rotating system. The linear theory for these centrifugal pendulum vibration absorbershas been thoroughly understood for many years, and some work on thenon-linear aspects of the dynamics has been carried out. These studies have focused on the effects that certain paths have for prescribed torques, but have not considered the construction of paths directly from the torques. Herein a classification of the torques is provided, which can be exactly counteracted by a single point absorber or by a pair of identical point absorbers moving out-of-phase with respect to each other. In additon, a technique is given for generating the absorber path(s) for these torques and the method is demonstrated with five examples. Also, design strategy is described by which one can use sets of absorbers to cancel a general periodic torque. These results provide a basis for the design of absorber path configurations and will be relevant to future work in which optimal paths are considered for more general torques.

Lee, C.-T.; Shaw, S. W.

1996-04-01

305

Development of a Safety Assessment Information System for the Management of Periodic Safety Assessment Activities  

Energy Technology Data Exchange (ETDEWEB)

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.

Song, Tae Young [Nuclear Engineering and Technology Institute, Daejeon (Korea, Republic of)

2007-07-01

306

BÜSYAT Periodicals Retrieval System BÜSYAT Süreli Yay?n Sorgulama Sistemi  

Directory of Open Access Journals (Sweden)

Full Text Available Nowadays it gets more difficult to access information in periodicals due to the increase in the number of these periodicals. But, on the other hand, computers are widely used today in different fields to complete jobs easily and efficiently. One of those applications is the easy and quick access to the required information in periodicals. User interfaces that form the bridge between human and machine undertake a critical role in access operations. Though as an extension of ergonomy discipline, a great experience of user interface design has been accumulated, still there would be some new system-specific design criteria for each new application. In this paper, a periodicals retrieval system and a software called BÜSYAT, designed and developed to take into account of the above mentioned considerations, are discussed and presented. Günümüzde say?s? gittikçe artmakta olan süreli yay?nlarda istenen bilgiye eri?im gitgide zorla?maktad?r. Ancak, di?er taraftan h?zland?r?c? ve kolayla?t?r?c? özelli?i olan bilgisayarlar pek çok alanda kullan?lmaktad?r. Söz konusu uygulamalardan birisi de süreli yay?nlarda istenen bilgiye kolay ve h?zl? eri?imin sa?lanabilmesidir. Bilgisayarlar ile kullan?c?lar aras?ndaki ba?lant?y? kuran kullan?c? arayüzleri ise bilgiye eri?im uygulamalar?nda kritik bir yol üstlenmektedir. Her ne kadar ergonomi disiplininin uzant?s? olarak son y?llarda bilgisayar programlar?nda arayüzü tasar?m? konusunda büyük bir birikim olmu?sa da, yine de her program için kendi özgün ko?ullar?na ba?l? olarak yeni bir tasar?m çal??mas? gerekmektedir. Bu makalede, yukar?da belirtilen hususlar do?rultusunda, süreli yay?nlarda bilgi eri?im amaçl? tasarlanm?? bir sistem ve bu tasar?m do?rultusunda geli?tirilmi? BÜSYAT adl? yaz?l?m tart???lmakta ve tan?t?lmaktad?r.

Meltem Özturan

1995-06-01

307

Optimal dispatching in a periodically review in on-line manufacturing system with vendors evaluation  

Directory of Open Access Journals (Sweden)

Full Text Available This paper, we consider dynamic dispatching control of a fully flexible online manufacturing system. Hence, vendors, who supply the materials, play an important role in this system. So, selection of vendors is much important. In a periodically reviewed, online manufacturing system where materials are dispatched from a central control station to different manufacturing sales. After production process, the parts are routed to inspection and quality control room. Hence optimal dispatching policies are pursued to minimize the in-process inventory carrying / holding cost over finite horizon. A dynamic programming formulation is developed for optimal dispatching which shows that the dynamic recursive functions (i.e. cost – to go – function are convex and monotonic under the condition of low defects rates and relative low cost material handling. From the derivation we conclude that optimal dispatching sales for a combination of zero inventory and Non- zero inventory policies. Thus, the optimal input control is proved to be in the form a pulling system.

Dipak Ranjan Jana

2011-04-01

308

Energy pay-back period analysis of stand-alone photovoltaic systems  

Energy Technology Data Exchange (ETDEWEB)

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)

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

309

IP Eri: A surprising long-period binary system hosting a He white dwarf  

CERN Document Server

We determine the orbital elements for the K0 IV + white dwarf (WD) system IP Eri, which appears to have a surprisingly long period of 1071 d and a significant eccentricity of 0.25. Previous spectroscopic analyses of the WD, based on a distance of 101 pc inferred from its Hipparcos parallax, yielded a mass of only 0.43 M$_\\odot$, implying it to be a helium-core WD. The orbital properties of IP Eri are similar to those of the newly discovered long-period subdwarf B star (sdB) binaries, which involve stars with He-burning cores surrounded by extremely thin H envelopes, and are therefore close relatives to He WDs. We performed a spectroscopic analysis of high-resolution spectra from the HERMES/Mercator spectrograph and concluded that the atmospheric parameters of the K0 component are $T_{\\rm eff} = 4960$ K, $\\log{g} = 3.3$, [Fe/H] = 0.09 and $\\xi = 1.5$ km/s. The detailed abundance analysis focuses on C, N, O abundances, carbon isotopic ratio, light (Na, Mg, Al, Si, Ca, Ti) and s-process (Sr, Y, Zr, Ba, La, Ce, N...

Merle, T; Masseron, T; Van Eck, S; Siess, L; Van Winckel, H

2014-01-01

310

Assessment of financial flow in the health system of Serbia in a period 2003-2006  

Directory of Open Access Journals (Sweden)

Full Text Available Background/Aim. The main goal of every health policy is not merely the establishment of the health system sustainability, but the accessibility of health services to the whole population, as well. This objective is shared in European Union countries, and the consequence is the implementation of National Health Accounts (NHA. NHA, as a tool for evidence-based management, provides data regarding financial flow in health at national level and alows international comparability. The aim of this study was to determine Serbian overall health spending patterns by National Health Accounts, and to determine health care indices to provide policy makers with internationally comparable health indicators. Methods. A retrospective analysis of healthcare expenditures was obtained from the published final financial reports of relevant state institutions during a period of 2003 to 2006. The various sources of data on healthcare expenditures were connected according to instructions by the OECD 'A System of Health Accounts (SHA' Version 1.0. Results. The obtained results showed: health expenditures in Serbia made up 8.6%, 8.3%, 8.7% and 9 % of the GDP in 2003, 2004, 2005 and 2006, respectively; the Health Insurance Fund was a predominant financing source of the public sector with 93% in 2006; the largest part of the total health expenditures went towards hospitals and for health services; the expenditure per capita in 2006 was 365 US$; Serbian population finances the state institutions 'out of pocket' with 21.28% of their sources, which was 7.3% of the total healthcare expenditures, and the private institutions with 78.72% of their financial sources, which is 27% of the total healthcare expenditures. In 2006 Serbia allocated financial resources out of GDP in the amount similar to the European Unity, while comparing to the countries of the region, these funds were less only than in Bosnia and Herzegovina. This allocating of financial resources in total, however, was low as the consequence of relatively low level of GDP in Serbia. Conclusion. Establishing NHA provided a pattern of national healtcare spending and allowed a comparison of healthcare system in Serbia with the systems of other countries. Analysing a period 2003- 2006 revealed a similarity between Serbia and the countries of the European Unity in regard to the level of average financial resources allocation for healthcare expressed as a percentage of GDP, as well as in regard to financiers in the system of healthcare. A high purchasing power disparity, however, in healthcare services was observed between the population of Serbia and other European countries.

Gaji?-Stevanovi? Milena

2010-01-01

311

Stochastic resonance in a time-delayed asymmetric bistable system with mixed periodic signal  

International Nuclear Information System (INIS)

This paper studies the phenomenon of stochastic resonance in an asymmetric bistable system with time-delayed feedback and mixed periodic signal by using the theory of signal-to-noise ratio in the adiabatic limit. A general approximate Fokker–Planck equation and the expression of the signal-to-noise ratio are derived through the small time delay approximation at both fundamental harmonics and mixed harmonics. The effects of the additive noise intensity Q, multiplicative noise intensity D, static asymmetry r and delay time ? on the signal-to-noise ratio are discussed. It is found that the higher mixed harmonics and the static asymmetry r can restrain stochastic resonance, and the delay time ? can enhance stochastic resonance. Moreover, the longer the delay time ? is, the larger the additive noise intensity Q and the multiplicative noise intensity D are, when the stochastic resonance appears. (general)

312

Periodic and chaotic oscillations in a tumor and immune system interaction model with three delays  

Science.gov (United States)

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.

Bi, Ping; Ruan, Shigui; Zhang, Xinan

2014-06-01

313

Microwave photoconductivity of two-dimensional electron systems with unidirectional periodic modulation  

CERN Document Server

Motivated by the recently discovered microwave-induced ``zero-resistance'' states in two-dimensional electron systems, we study the microwave photoconductivity of a two-dimensional electron gas (2DEG) subject to a unidirectional static periodic potential. The combination of this potential, the classically strong magnetic field, and the microwave radiation may result in an anisotropic negative conductivity of the 2DEG. Similar to the case of a smooth random potential, two mechanisms contribute to the negative photoconductivity. The displacement mechanism arises from electron transitions due to disorder-assisted microwave absorption and emission. The distribution-function mechanism arises from microwave-induced changes in the electron distribution. However, the replacement of a smooth random potential by the unidirectional one, leads to different relative strengths of the two contributions to the photoconductivity. The distribution function mechanism dominates the photoconductivity in the direction of the stati...

Dietel, J; Hekking, F; Von Oppen, F

2004-01-01

314

Periodic and chaotic oscillations in a tumor and immune system interaction model with three delays.  

Science.gov (United States)

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. PMID:24985415

Bi, Ping; Ruan, Shigui; Zhang, Xinan

2014-06-01

315

Discharge formation systems for generating atomic iodine in a pulse-periodic oxygen-iodine laser  

Science.gov (United States)

Generation characteristics of a pulse-periodic oxygen-iodine laser with the electro-discharge production of atomic iodine were compared with inductively stabilised edged or anisotropic- resistive cathodes used for ignition of the volume discharge. The discharge was initiated by the radiation of a barrier discharge from the side of a grid anode. It was found that at equal specific electrical energy depositions to the gas-discharge plasma, the system with the anisotropic-resistive cathode provides a more stable and uniform volume discharge with the possibility of varying the composition and pressure of working mixtures over a wide range and a greater specific extraction of laser energy is observed (up to 2.4 J L-1). At a high pulse repetition rate of laser pulses (50 - 100 Hz) and long duration of the pulse trains (longer than a minute) the surface of anisotropic-resistive cathode became eroded.

Aksinin, V. I.; Antsiferov, S. A.; Velikanov, S. D.; Gerasimov, A. Yu; Gostev, I. V.; Kazantsev, S. Yu; Kalinovskii, V. V.; Konovalov, V. V.; Kononov, I. G.; Mikhalkin, V. N.; Podlesnykh, S. V.; Sevryugin, I. V.; Firsov, K. N.

2014-01-01

316

Periodic and chaotic oscillations in a tumor and immune system interaction model with three delays  

International Nuclear Information System (INIS)

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

317

Note: Signal conditioning of a hot-film anemometer for a periodic flow rate monitoring system.  

Science.gov (United States)

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. PMID:22225264

Mantovani, Federico; Tagliaferri, Cristian

2011-12-01

318

Periodic and chaotic oscillations in a tumor and immune system interaction model with three delays  

Energy Technology Data Exchange (ETDEWEB)

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.

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

319

Stochastic sensitivity analysis of periodic attractors in non-autonomous nonlinear dynamical systems based on stroboscopic map  

Science.gov (United States)

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.

Guo, Kong-Ming; Jiang, Jun

2014-07-01

320

Assessment of the expected number and frequency of failures of periodically tested systems  

International Nuclear Information System (INIS)

The safety and reliability analysis of any system necessarily requires first to model its behavior or its failure logic, and second to assess its performance by using the previously chosen model. Among these performance indicators there is the failure frequency. In spite of its interest, it is not very often used, except in the standards devoted to the so-called functional safety, in which its genuine nature is not always made explicit. A sound method dedicated to the modeling and computing of the failure frequency of periodically tested systems is proposed in this paper. This type of systems comprises components with an availability curve which is discontinuous at deterministic instants. These discontinuities induce, in turn and at the same instants, frequency discontinuities. The impact of the latter on the overall value of the failure frequency is important, but largely unknown and therefore not taken into account in the safety and reliability area, in spite of the fact that it generally induces optimistic estimation, if no compensatory action is planned. The presented method is based on the notion of “critical state” and the use of advanced fault tree models (FT). The results obtained from these models are checked by using Monte Carlo simulation technique supported by equivalent Petri nets models (PN)

 
 
 
 
321

[Experiences with the psychometric system combitest in the evaluation of the postnarcotic arousal period].  

Science.gov (United States)

Since the introduction of new German health legislation, operations formerly performed on an in-patient basis have been transferred to the out-patient sector. Due to this development evaluating the postnarcotic arousal period has become increasingly important. Vigilance, reactivity and state of health determine a patient's well-being and time of discharge after an operation and consequently influence economical and legal issues. Former studies investigating the arousal period have mainly focused on patient interviews and assessment of patients by staff. The aim of our study was to objectivize postnarcotic vigilance and reactivity (critical flicker fusion frequency and multiple choice reaction) using neurophysiological monitoring (psychometric system Combitest 2: CFF, EWR, MWR). The applied methods have been defined as valid, reliable and sensitive tools to investigate this question. Inter-individual and gender-specific differences as well as variations due to the type of anaesthetic employed can be detected. The study participants assessed the test battery's practicability and overall described this method as easy to use. Vigilance (CFF), basic and complex sensomotor reactivity (performance in simple and multiple choice tests) were restored after a postanaesthetic phase of 90 minutes (narcotics applied: isofluran and propofol). The results show that the use of modern anaesthetics does not justify the current medical and legal claim to 6 hours of postanaesthetic observation. The computer-supported psychometric system Combitest 2 has recently been used to assess the arousal phase after application of different types of anaesthetical procedures (TIVA, volatile, balanced) and has been found to be superior to parameters traditionally used to assess discharge criteria (time until patient opens eyes, orientation concerning time and location, time spent in postanaesthetic recovery room). Besides employing our study methods, subjective factors such as well-being and pain sensation should also be evaluated when determining the time of a patient's discharge. PMID:11967747

Winter, C G; Hagemann, H; Hamann, R; Markus, H; Ferl, Th; Hammer-Reitzig, S; Pfister, E A

2002-04-01

322

Investigation of periodic systems by means of the generalized Hill method  

International Nuclear Information System (INIS)

We propose the new method of investigation of infinite periodic determination which is a generalized Hill method. This method has been used for finding of the characteristic value for the Hill equation. finding the band structure of the one-dimensional periodic and obtaining of the dispersion equation for the electromagnetic wave propagation in the waveguide by plasma arbitrary periodic density modulation by plasma arbitrary periodic density modulation

323

Weak-Coupling Theory for Semiclassical Periodically Driven Two-Level Systems: Beyond Rotating-Wave Approximation  

International Nuclear Information System (INIS)

We present a weak-coupling theory of semiclassical periodically driven two-level systems. The explicit analytical approximating solution is shown to reproduce highly accurately the exact results well beyond the regime of the rotating-wave approximation.

324

Frictional systems under periodic loads — History-dependence, non-uniqueness and energy dissipation  

Science.gov (United States)

Nominally static contacts such as bolted or shrink-fit joints typically experience regions of microslip when subjected to oscillatory loading. This results in energy dissipation, reflected as apparent hysteretic damping of the system, and also may cause the initiation of fretting fatigue cracks. Early theoretical studies of the Hertzian contact problem by Cattaneo and Mindlin were confirmed experimentally by Johnson, who identified signs of fretting damage in the slip annulus predicted by the theory. For many years, tribologists assumed that Melan's theorem in plasticity could be extended to frictional systems — i.e. that if there exists a state of residual stress associated with frictional slip that is sufficient to prevent periodic slip in the steady state, then the system will shake down, regardless of the initial condition. However, we now know that this is true only if there is no coupling between the normal and tangential loading problems, as will be the case notably when contact occurs on a symmetry plane. For all other cases, periodic loading scenarios can be devised such that shakedown occurs for some initial conditions and not for others. The initial condition here might be determined by the assembly protocol — e.g. the order in which a set of bolts is tightened — or by the exact loading path before the steady cycle is attained. This non-uniqueness of the steady state persists at load amplitudes above the shakedown limit, in which case there is always some dissipation, but the dissipation per cycle (and hence both the effective damping and the susceptibility to fretting damage) depends on the initial conditions. This implies that fretting fatigue experiments need to follow a well-defined assembly protocol if reproducible results are to be obtained. We shall also present results showing that when both normal and tangential forces vary in time, the energy dissipation is very sensitive to the relative phase of the oscillatory components, being greatest when they are out of phase. With sufficient clamping force, 'complete' contacts (i.e. those in which the contact area is independent of the normal load) can theoretically be prevented from slipping, but on the microscale, all contacts are incomplete because of surface roughness and some microslip is inevitable. In this case, the local energy dissipation density can be estimated from relatively coarse-scale roughness models, based on a solution of the corresponding 'full stick' problem.

Barber, J. R.

2012-08-01

325

KIC 4544587: an Eccentric, Short Period Binary System with delta Sct Pulsations and Tidally Excited Modes  

CERN Document Server

We present Kepler photometry and ground based spectroscopy of KIC 4544587, a short-period eccentric eclipsing binary system with self-excited pressure and gravity modes, tidally excited modes, tidally influenced p modes, and rapid apsidal motion of 182 y per cycle. The primary and secondary components of KIC 4544587 reside within the delta Scuti and gamma Dor instability region of the Hurtzsprung-Russell diagram, respectively. By applying the binary modelling software PHOEBE to prewhitened Kepler photometric data and radial velocity data obtained using the William Herschel Telescope and 4-m Mayall telescope at KPNO, the fundamental parameters of this important system have been determined, including the stellar masses, 1.98+/-0.07 MSun and 1.60+/-0.06 MSun, and radii, 1.76+/-0.03 RSun and 1.42+/-0.02 RSun, for the primary and secondary components, respectively. Frequency analysis of the residual data revealed 31 modes, 14 in the gravity mode region and 17 in the pressure mode region. Of the 14 gravity modes 8 ...

Hambleton, K M; Prsa, A; Guzik, J A; Pavlovski, K; Bloemen, S; Southworth, J; Conroy, K; Littlefair, S P; Fuller, J

2013-01-01

326

PHYSICAL PROPERTIES OF THE 0.94-DAY PERIOD TRANSITING PLANETARY SYSTEM WASP-18  

International Nuclear Information System (INIS)

We present high-precision photometry of five consecutive transits of WASP-18, an extrasolar planetary system with one of the shortest orbital periods known. Through the use of telescope defocusing we achieve a photometric precision of 0.47-0.83 mmag per observation over complete transit events. The data are analyzed using the JKTEBOP code and three different sets of stellar evolutionary models. We find the mass and radius of the planet to be M b = 10.43 ± 0.30 ± 0.24 M Jup and R b = 1.165 ± 0.055 ± 0.014 R Jup (statistical and systematic errors), respectively. The systematic errors in the orbital separation and the stellar and planetary masses, arising from the use of theoretical predictions, are of a similar size to the statistical errors and set a limit on our understanding of the WASP-18 system. We point out that seven of the nine known massive transiting planets (M b > 3 M Jup) have eccentric orbits, whereas significant orbital eccentricity has been detected for only four of the 46 less-massive planets. This may indicate that there are two different populations of transiting planets, but could also be explained by observational biases. Further radial velocity observations of low-mass planets will make it possible to choose between these two scenarios.

327

Effect of local or systemic hydrocortisone on skin wound healing resistance, in different postoperative periods  

Directory of Open Access Journals (Sweden)

Full Text Available Objectives: To compare the resistance of skin wound healing of mice submitted to local or systemic hydrocortisone administration, in different postoperative periods. Methods: An incision and suture was performed on the thoracic skin of 130 male mice: Group 1(n = 10 resistance of the integer skin; Group 2 (n = 30 submitted only to skin incision and suture; Group 3 (n = 30 skin incision and suture followed by administration of saline fluid; Group 4(n = 30 skin incision and suture followed by administration of local hydrocortisone; Group 5 (n = 30 skin incision and suture followed by administration of systemic hydrocortisone. The resistance of the wound healing and the weight of the animals were studied on the seventh, 14th and 21st postoperative days. Histologic examination was also performed. Rresults: The mice that received corticoid (Groups 4 and 5 presented significant decreasing on their weight (p = 0.02. The Groups 3, 4 and 5 showed lower scar resistance than Group 2 on the seventh postoperative day (p 0.05. Cconclusions: Administration of hydrocortisone in mice is responsible for weight decreasing and reduction of the skin wound healing resistance during the first postoperative week.

Luiz Ronaldo Alberti

2008-09-01

328

Short-period low-mass binary system CC Com revisited  

CERN Document Server

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.

Kose, O; Keskin, V; Ulas, B; Yakut, K

2011-01-01

329

Narrow band filter using 1D periodic structure with defects for DWDM systems  

Science.gov (United States)

A 1D binary periodic structure with defect has been analysed using Transfer Matrix Method. For a particular nine layered structure of SiO2 and InP, a number of full stop bands (in other words, zero passbands or forbidden bands) at different regions of the spectrum under investigation are observed. Introducing a central spatial defect in the system by adjusting the layer width, it is possible to achieve an extremely narrow passband centred on 1554.9 nm in the 7th forbidden band. Moreover by varying the defect width, the number of passbands can be increased. These passbands have flat and 100% stopband and hence can be better candidate to drop single or multiple frequencies in WDM systems. It is further observed that with increase in the number of layers and/or defect width, the number of mini pass bands outside the original forbidden band also increases. Also by FDTD simulation it is seen that the field is localised within the defect for the passband frequency.

Ghosh, R.; Ghosh, K. K.; Chakraborty, R.

2013-02-01

330

The shortest-period M-dwarf eclipsing system BW3 V38  

CERN Document Server

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.

Maceroni, C; Maceroni, Carla; Rucinski, Slavek M.

1997-01-01

331

Bifurcation and complex dynamics of a two-prey two-predator system concerning periodic biological and chemical control  

International Nuclear Information System (INIS)

In this paper, we investigate the dynamic behaviors of a two-prey two-predator system with impulsive effect concerning biological and chemical control strategy-periodic releasing natural enemies and spraying pesticide at different fixed time. By applying the Floquet theory of linear periodic impulsive equation and small amplitude perturbation method, we prove that there exists a globally asymptotically stable two-prey-eradication periodic solution when the impulsive period is less than some critical value. The conditions for the permanence of the system are given, and meanwhile the conditions for the extinction of one of the two prey species and permanence of the remaining three species are given. Our results suggest a new approach in pest control. The target pest population can be driven to extinction and the non-target pest can be permanent by choosing impulsive period. With the increasing of the predation rate for the super competitor and impulsive period, the system displays complicated behaviors including a sequence of direct and inverse cascades of periodic-doubling, periodic-halfing, chaos, and symmetry breaking bifurcation

332

Interuser Interference Analysis for Direct-Sequence Spread-Spectrum Systems Part I: Partial-Period Cross-Correlation  

Science.gov (United States)

This presentation discusses an analysis approach to evaluate the interuser interference for Direct-Sequence Spread-Spectrum (DSSS) Systems for Space Network (SN) Users. Part I of this analysis shows that the correlation property of pseudo noise (PN) sequences is the critical factor which determines the interuser interference performance of the DSSS system. For non-standard DSSS systems in which PN sequence s period is much larger than one data symbol duration, it is the partial-period cross-correlation that determines the system performance. This study reveals through an example that a well-designed PN sequence set (e.g. Gold Sequence, in which the cross-correlation for a whole-period is well controlled) may have non-controlled partial-period cross-correlation which could cause severe interuser interference for a DSSS system. Since the analytical derivation of performance metric (bit error rate or signal-to-noise ratio) based on partial-period cross-correlation is prohibitive, the performance degradation due to partial-period cross-correlation will be evaluated using simulation in Part II of this analysis in the future.

Ni, Jianjun (David)

2012-01-01

333

Towards a Fundamental Understanding of Short Period Eclipsing Binary Systems Using Kepler Data  

Science.gov (United States)

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-to-primary light ratio regime of ~1-2% for the circumbinary host system Kepler-16. Semi-detached binaries are ideal targets to study the dynamical processes such as mass flow and accretion, and the associated thermal processes such as intensity variation due to distortion of the lobe-filling component and material inflow collisions with accretion disks. Overcontact binaries are very abundant, yet their evolution and radiative properties are poorly understood and conflicting theories exist to explain their population frequency and structure. In addition, we will measure eclipse timing variations for all program binaries that attest to the presence of perturbing third bodies (stellar and substellar!) or dynamical interaction between the components. By a dedicated, detailed, manual modeling of these sets of targets, we will be able to use Kepler's ultra-high precision photometry to a rewarding scientific end. Thanks to the unprecedented quality of Kepler data, this will be a highly focused effort that maximizes the scientific yield and the reliability of the results. Our team has ample experience dealing with Kepler data (PI Prsa serves as chair of the Eclipsing Binary Working Group in the Kepler Science Team), spectroscopic follow-up (Co-Is Mahadevan and Bender both have experience with radial velocity instrumentation and large spectroscopic surveys), and eclipsing binary modeling (PI Prsa and Co-I Devinney both have a long record of theoretical and computational development of modeling tools). The bulk of funding we are requesting is for two postdoctoral research fellows to conduct this work at 0.5 FTE/year each, for the total of 2 years.

Prsa, Andrej

334

Periodicity suppression in continuous-time dynamical systems by external forcing.  

Science.gov (United States)

We investigate periodicity suppression by an external periodic forcing in different flows, each modeled by a set of three autonomous nonlinear first-order ordinary differential equations. By varying the amplitude of a sinusoidal forcing with a fixed angular frequency, we show through numerical simulations, including parameter planes plots, phase-space portraits, and the largest Lyapunov exponent, that windows of periodicity embedded in chaotic regions may be totally suppressed. PMID:23278082

Mathias, Amanda C; Rech, Paulo C

2012-12-01

335

Orbital periods of cataclysmic variables identified by the SDSS. IX. NTT photometry of eight eclipsing and three magnetic systems  

CERN Document Server

We report the discovery of eclipses and the first orbital period measurements for four cataclysmic variables, plus the first orbital period measurements for one known eclipsing and two magnetic systems. SDSS J093537.46+161950.8 exhibits 1-mag deep eclipses with a period of 92.245 min. SDSS J105754.25+275947.5 has short and deep eclipses and an orbital period of 90.44 min. Its light curve has no trace of a bright spot and its spectrum is dominated by the white dwarf component, suggesting a low mass accretion rate and a very low-mass and cool secondary star. CSS J132536+210037 shows 1-mag deep eclipses each separated by 89.821 min. SDSS J075653.11+085831.8 shows 2-mag deep eclipses on a period of 197.154 min. CSS J112634-100210 is an eclipsing dwarf nova identified in the Catalina Real Time Transit Survey, for which we measure a period of 111.523 min. SDSS J092122.84+203857.1 is a magnetic system with an orbital period of 84.240 min; its light curve is a textbook example of cyclotron beaming. A period of 158.72...

Southworth, John; Gaensicke, B T; Copperwheat, C M

2014-01-01

336

Vitamin A determination in milk samples based on the luminol-periodate chemiluminescence system.  

Science.gov (United States)

A simple and rapid flow injection (FI) method for the determination of retinyl acetate is reported based on its enhancing effect on the luminol-periodate chemiluminescence (CL) system in an alkaline medium. The detection limit (3s×blank) was 8.0×10?? mol L?¹, with an injection throughput of 90 h?¹. The method allows linear increase of CL intensity over the retinyl acetate concentration range of 1.0-100×10?? mol L?¹ (R²=0.9996) with relative standard deviations of 2.4% (n=10) for 5.0×10?? mol L?¹. The key chemical and physical variables (reagent concentrations, flow rates, sample volume, and photomultiplier tube (PMT) voltage) were optimized and potential interferences were investigated. The method was successfully applied to human milk, fresh cow's milk and infant milk-based formulas and the results were in good agreement with the previously reported HPLC method. A brief discussion on the possible CL reaction mechanism is also presented. PMID:24759254

Rishi, Lubna; Yaqoob, Mohammad; Waseem, Amir; Nabi, Abdul

2014-01-01

337

Identifying parameters of multi-degree-of-freedom nonlinear structural dynamic systems using linear time periodic approximations  

Science.gov (United States)

The authors recently presented a new nonlinear system identification method, here dubbed the NL-LTP method, in which the system of interest is forced harmonically so that it responds in a stable periodic orbit, and then it is perturbed slightly and its response is recorded as it returns to the orbit. Under mild assumptions the response about the periodic orbit can be approximated using a linear time periodic system model, which can be identified from the measurements using techniques that are akin to linear modal analysis. While the prior work focused on simulated measurements from single degree-of-freedom systems, this work presents several tools that are needed in order to use this approach on multi-degree-of-freedom systems and focuses on applying the method to experimental hardware. The proposed system identification methodology is unique in that it identifies both the order of the nonlinear system and a mathematical model for the nonlinear restoring forces without assuming the mathematical form for the nonlinearities a priori. Towards these ends, this work explains how to extract the underlying nonlinear system model, or nonlinear restoring force versus displacement relationships, from the time periodic model that governs deviations of the system from its periodic orbit, and presents various metrics that can be used to determine which terms in the model are meaningful. These new tools are used to apply the identification method to a continuous, multi-degree-of-freedom structure with a discrete geometric nonlinearity, using both simulated and experimental measurements. The experimental hardware consists of a cantilever beam with a nonlinear spring attached to its tip, which is driven in a periodic limit cycle by an electromagnetic shaker.

Sracic, Michael W.; Allen, Matthew S.

2014-06-01

338

Positive periodic solution of a general discrete non-autonomous difference system of plankton allelopathy with delays  

Science.gov (United States)

The main purpose of this paper is to investigate a discrete time non-autonomous difference system of plankton allelopathy with delays. By employing continuous theorem proposed by Gains and Mawhin and some new techniques, a set of verifiable sufficient criteria are established for the existence of at least one strictly positive (componentwise) periodic solution, and as an application, we also examine some special case, showing that these conditions are similar to those of continuous differential system. It is also shown that the time delays are harmless for the existence of positive periodic solutions of system.

Liu, Zhijun; Chen, Lansun

2006-12-01

339

Emergency Diesel Generation System Surveillance Test Policy Optimization Through Genetic Algorithms Using Non-Periodic Intervention Frequencies and Seasonal Constraints  

International Nuclear Information System (INIS)

Nuclear standby safety systems must frequently, be submitted to periodic surveillance tests. The main reason is to detect, as soon as possible, the occurrence of unrevealed failure states. Such interventions may, however, affect the overall system availability due to component outages. Besides, as the components are demanded, deterioration by aging may occur, penalizing again the system performance. By these reasons, planning a good surveillance test policy implies in a trade-off between gains and overheads due to the surveillance test interventions. In order maximize the systems average availability during a given period of time, it has recently been developed a non-periodic surveillance test optimization methodology based on genetic algorithms (GA). The fact of allowing non-periodic tests turns the solution space much more flexible and schedules can be better adjusted, providing gains in the overall system average availability, when compared to those obtained by an optimized periodic tests scheme. The optimization problem becomes, however, more complex. Hence, the use of a powerful optimization technique, such as GAs, is required. Some particular features of certain systems can turn it advisable to introduce other specific constraints in the optimization problem. The Emergency Diesel Generation System (EDGS) of a Nuclear Power Plant (N-PP) is a good example for demonstrating the introduction of seasonal constraints in the optimization problem. This system is responstimization problem. This system is responsible for power supply during an external blackout. Therefore, it is desirable during periods of high blackout probability to maintain the system availability as high as possible. Previous applications have demonstrated the robustness and effectiveness of the methodology. However, no seasonal constraints have ever been imposed. This work aims at investigating the application of such methodology in the Angra-II Brazilian NPP EDGS surveillance test policy optimization, considering the blackout probability growth during summer, due to the electrical power demand increase. Here, the model used penalizes test interventions by a continuous modulating function, which depends on the instantaneous blackout probability. Results have demonstrated the ability of the method in adapting the surveillance tests policy to seasonal behaviors. The knowledge acquired by the GA during the searching process has lead to test schedules that drastically minimize the test interventions at periods of high blackout probability. It is compensated by more frequent tests redistributed through the periods of low blackout probability, in order to provide improvement on the overall average availability at the system level. (authors)

340

DISK-PLANETS INTERACTIONS AND THE DIVERSITY OF PERIOD RATIOS IN KEPLER'S MULTI-PLANETARY SYSTEMS  

Energy Technology Data Exchange (ETDEWEB)

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.

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

 
 
 
 
341

Permanence for a class of periodic time-dependent predator-prey system with dispersal in a patchy-environment  

International Nuclear Information System (INIS)

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

342

Permanence for a class of periodic time-dependent predator-prey system with dispersal in a patchy-environment  

Energy Technology Data Exchange (ETDEWEB)

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.

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

343

Chemiluminescence determination of mezlocillin by the luminol-potassium periodate system  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Um método novo, simples e sensível foi proposto para a determinação de mezlocilina. Baseia-se na amplificação da emissão de quimiluminescência (CL) gerada a partir da oxidação do luminol em meio alcalino pelo periodato de potássio. A otimização das variáveis experimentais e instrumentais que afetam [...] o efeito da amplificação de CL foi realizada usando-se sistema de injeção em fluxo. Em condições ótimas, o método é eficiente para determinar mezlocilina no intervalo linear de 0,01 a 30 ×10-6 g mL-1 com limite de detecção (3?) de 3,0×10-9 g mL-1 e desvio padrão relativo (RSD) de 1,0% para 1,0×10-6 g mL-1 de mezlocilina (n=11). O método tem sido aplicado com sucesso, para determinação de mezlocilina em preparações comerciais, amostras sintéticas e formulações biológicas fluidas. Abstract in english A new, simple and sensitive method has been proposed for the determination of mezlocillin. It is based on the enhancement of the chemiluminescence (CL) emission generated from the oxidation of luminol in alkaline medium by postassium periodate. The optimization of the experimental and instrumental v [...] ariables affecting the CL enhancement effect has been carried out using flow-injection system. In the optimum conditions, the method is efficient to determine mezlocillin in the linear range of 0.01-30×10-6 g mL-1 with a detection limit (3?) of 3.0×10-9 g mL-1 and the relative standard deviation (RSD) is 1.0% for 1.0×10-6 g mL-1 mezlocillin (n=11). It has been successfully applied to the mezlocillin determination in commercial preparations, synthetic samples and biological fluids formulations.

Wen Bing, Shi; Ji Dong, Yang.

1180-11-01

344

Critical experiments on an enriched uranium solution system containing periodically distributed strong thermal neutron absorbers  

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

345

Critical experiments on an enriched uranium solution system containing periodically distributed strong thermal neutron absorbers  

Energy Technology Data Exchange (ETDEWEB)

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.

Rothe, R.E.

1996-09-30

346

Chemiluminescence determination of mezlocillin by the luminol-potassium periodate system  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Um método novo, simples e sensível foi proposto para a determinação de mezlocilina. Baseia-se na amplificação da emissão de quimiluminescência (CL) gerada a partir da oxidação do luminol em meio alcalino pelo periodato de potássio. A otimização das variáveis experimentais e instrumentais que afetam [...] o efeito da amplificação de CL foi realizada usando-se sistema de injeção em fluxo. Em condições ótimas, o método é eficiente para determinar mezlocilina no intervalo linear de 0,01 a 30 ×10-6 g mL-1 com limite de detecção (3?) de 3,0×10-9 g mL-1 e desvio padrão relativo (RSD) de 1,0% para 1,0×10-6 g mL-1 de mezlocilina (n=11). O método tem sido aplicado com sucesso, para determinação de mezlocilina em preparações comerciais, amostras sintéticas e formulações biológicas fluidas. Abstract in english A new, simple and sensitive method has been proposed for the determination of mezlocillin. It is based on the enhancement of the chemiluminescence (CL) emission generated from the oxidation of luminol in alkaline medium by postassium periodate. The optimization of the experimental and instrumental v [...] ariables affecting the CL enhancement effect has been carried out using flow-injection system. In the optimum conditions, the method is efficient to determine mezlocillin in the linear range of 0.01-30×10-6 g mL-1 with a detection limit (3?) of 3.0×10-9 g mL-1 and the relative standard deviation (RSD) is 1.0% for 1.0×10-6 g mL-1 mezlocillin (n=11). It has been successfully applied to the mezlocillin determination in commercial preparations, synthetic samples and biological fluids formulations.

Wen Bing, Shi; Ji Dong, Yang.

347

Periodic Solutions of Impulsive Predator?prey System With Time?Varying ?Delays and Watt?Type Functional Response  

Directory of Open Access Journals (Sweden)

Full Text Available Delay phenomenon and pulse effects in biological systems exist widespread. Because taking into account the ecological system with time?delay and pulse effect is of great theoretical and practical significance, a class model of impulsive predator?prey system with variable delays and Watt type functional response is considered in this paper. By using the differential inequality comparison with pulse, the continuation theorem of coincidence degree theory, homotopy invariance property, some sufficient conditions ensuring the existence of positive periodic solutions of the system are obtained. That is, there is at least one positive periodic solution for the impulsive system if one of the following conditions is satisfied. And prior bounds are given to keep these qualities of the system. The results improve and extend some recent works.

YANG Zhi-chun

2012-09-01

348

Orbital periods of cataclysmic variables identified by the SDSS. VI. The 4.5-h period eclipsing system SDSS J100658.40+233724.4  

Science.gov (United States)

We present time-resolved spectroscopy and photometry of SDSS J100658.40+233724.4, which we have discovered to be an eclipsing cataclysmic variable with an orbital period of 0.18591324 days (267.71507 min). The observed velocity amplitude of the secondary star is 276 ± 7 km s-1, which an irradiation correction reduces to 258 ± 12 km s-1. Doppler tomography of emission lines from the infrared calcium triplet supports this measurement. We have modelled the light curve using the lcurve code and Markov Chain Monte Carlo simulations, finding a mass ratio of 0.51 ± 0.08. From the velocity amplitude and the light curve analysis we find the mass of the white dwarf to be 0.78 ± 0.12 {{M}_?} and the masses and radii of the secondary star to be 0.40 ± 0.10 {{M}_?} and 0.466 ± 0.036 {{R}_?}, respectively. The secondary component is less dense than a normal main sequence star but its properties are in good agreement with the expected values for a CV of this orbital period. By modelling the spectral energy distribution of the system we find a distance of 676 ± 40 pc and estimate a white dwarf effective temperature of 16 500 ± 2000 K. Spectra are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/507/929

Southworth, J.; Hickman, R. D. G.; Marsh, T. R.; Rebassa-Mansergas, A.; Gänsicke, B. T.; Copperwheat, C. M.; Rodríguez-Gil, P.

2009-11-01

349

The effect of disorder on the wave propagation in one-dimensional periodic optical systems  

CERN Document Server

The influence of disorder on the transmission through periodic waveguides is studied. Using a canonical form of the transfer matrix we investigate dependence of the Lyapunov exponent $\\gamma$ on the frequency $\

Godin, Yuri A; Vainberg, Boris; 10.1080/17455030.2010.528064

2011-01-01

350

75 FR 76928 - Safety Management System for Certificated Airports; Extension of Comment Period  

Science.gov (United States)

...on October 13, 2010, the Experimental Aircraft Association (EAA) requested that the comment period be extended by the same...the petitions made by the Experimental Aircraft Association (EAA), Airports Council International, North America...

2010-12-10

351

Period-3 catastrophe and enhanced diffusion in two-dimensional Hamiltonian systems  

International Nuclear Information System (INIS)

Quantitative analysis of the period-3 catastrophe is developed for the standard map and for the stochastic heating map as illustrative examples of two-dimensional area preserving mappings. Analytic expression of the diffusion coefficient is derived for the stochastic heating, and compared to results of numerical observation. Here, as for the case of the standard map, the multi-periodic accelerator modes give rise to anomalous enhancement of the diffusion rate. (author)

352

Efficient switching between controlled unstable periodic orbits in higher dimensional chaotic systems  

International Nuclear Information System (INIS)

We develop an efficient targeting techique and demonstrate that when used with an unstable periodic orbit stabilization method, fast and efficient switching between controlled periodic orbits is possible. This technique is particularly relevant to cases of higher attractor dimension. We present a numerical example and report an improvement of up to four orders of magnitude in the switching time over the case with no targeting

353

An efficient tracer experimental design for measuring time-variable transit time distributions in periodic hydrodynamic systems  

Science.gov (United States)

The time-varying transport dynamics of complex hydrodynamic systems with long transit times are difficult to observe even in experimental systems due to the need for multiple tracer injections. Where only one or two distinct tracers are available, overprinting in the output concentrations limits the injection frequency. We will present an experimental method (the PERiodic Tracer Hierarchy - PERTH) that allows overprinted breakthrough curves to be decomposed into contributions from multiple injections of the same tracer, so long as the transporting flow is periodic. This method allows the time varying transit time distributions to be observed efficiently while making no a priori assumptions about the transport processes operating in the system. Simulations of transport through a soil column subject to a periodic sequence of irrigation events demonstrate that the distinct transit time distributions associated with each irrigation event can be retrieved almost exactly.

Harman, Ciaran; Kim, Minseok

2014-05-01

354

Electrostatic Interactions in Finite Systems treated with Periodic Boundary Conditions: Application to Linear-Scaling Density Functional Theory  

CERN Document Server

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 ...

Hine, N D M; Haynes, P D; Skylaris, C K

2011-01-01

355

A dynamical systems analysis of the kinematics of time-periodic vortex shedding past a circular cylinder  

Science.gov (United States)

Computer flow simulation aided by dynamical systems analysis is used to investigate the kinematics of time-periodic vortex shedding past a two-dimensional circular cylinder in the context of the following general questions: (1) Is a dynamical systems viewpoint useful in the understanding of this and similar problems involving time-periodic shedding behind bluff bodies; and (2) Is it indeed possible, by adopting such a point of view, to complement previous analyses or to understand kinematical aspects of the vortex shedding process that somehow remained hidden in previous approaches. We argue that the answers to these questions are positive. Results are described.

Ottino, Julio M.

1991-01-01

356

Survival probability and saturation energy in periodically driven quantum chaotic systems  

Energy Technology Data Exchange (ETDEWEB)

We study characteristics of the steady state of a random-matrix model with periodical pumping, where the energy increase saturates by quantum localization. We study the dynamics by making use of the survival probability. We found that Floquet eigenstates are separated into the localized and extended states, and the former governs the dynamics. -- Highlights: ? We study the steady state of a random-matrix model with periodical pumping. ? We study the saturated energy using the survival probability. ? Floquet eigenstates are separated into the localized and extended states. ? The former eigenstates govern the dynamics.

Machida, Manabu, E-mail: mmachida@umich.edu [Department of Mathematics, University of Michigan, Ann Arbor, MI 48109 (United States); Miyashita, Seiji, E-mail: miya@spin.phys.s.u-tokyo.ac.jp [Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2012-04-30

357

Tunable wideband bandstop acoustic filter based on 2D multi-physical phenomena periodic systems  

CERN Document Server

The physical properties of a periodic distribution of absorbent resonators is used in this work to design a tunable wideband bandstop acoustic filter. Analytical and numerical simulations as well as experimental validations show that the control of the resonances and the absorption of the scatterers along with their periodic arrangement in air introduces high technological possibilities to control noise. Sound manipulation is perhaps the most obvious application of the structures presented in this work. We apply this methodology to develop a device as an alternative to the conventional acoustic barriers with several properties from the acoustical point of view but also with additional aesthetic and constructive characteristics.

Romero-García, V; Garcia-Raffi, L M

2011-01-01

358

Photometric study of the short period W UMa system VW Cephei  

CERN Document Server

A total of 431 photoelectric B and V observations are presented for the short period . The measurements have been obtained in two successive nights, 27/28 and 28/29 of September 1995, and represent the whole light curve phases. Four times of minimum light, for each filter, were deduced and new periods have been derived as 0.277892 day from the present photometric observations. New light curves have been constructed, investigated and analyzed by using the recent version of W-D code.

Essam, A; Haroon, A A

2014-01-01

359

Mutual Inhibition, Competition, and Periodicity in a Two Species Chemostat-like System  

Directory of Open Access Journals (Sweden)

Full Text Available A model addressing mutual inhibition in a peiodic chemostat is presented in this paper. The operating parameters, including the nutirent uptake function, washout rate, and nutrient concentration are allowed to be periodic functions of time, with comensurate periods. It is shown that with mutual inhibition, competitive exclusion always holds in models that would allow coexistence without inhibition. We further show that initial conditions play a crucial role in determining which species survives. Simulations using MATLAB appear to confirm the predictions of the models. Some results from the simulations are presented graphically.

George Kimathi

2012-05-01

360

Proof of the existence of wave operators for the hyperbolic systems with a potential periodic in time  

International Nuclear Information System (INIS)

We prove the existence of the scattering operator for the wave equation with a potential which is periodic in time and has compact support in space, in dimension greater than or equal to 3, provided the energy is uniformly bounded. The key result is the decay of the local energy. The RAGE theorem of Georgiev and Petkov implies weak decay and we get strong convergence by using the compactness of the local evolution operator, derived from a microlocal analysis of the propagation of singularities. In the case where the dimension is odd, the decay is exponential for initial data: i) with compact support and ii) included in a subspace of finite codimension. We give some sufficient conditions for the boundedness of the energy by studying the spectrum of the local evolution operator. We extend these results to first order hermitian systems with arbitrary multiplicity and with a periodic potential such as the Dirac system in a periodic electromagnetic field

 
 
 
 
361

The systemic velocities of four long-period cataclysmic variable stars  

CERN Document Server

Although a large number of orbital periods of cataclysmic variable stars (CVs) have been measured, comparison of period and luminosity distributions with evolutionary theory is affected by strong selection effects. A test has been discovered which is independent of these selection effects and is based upon the kinematics of CVs (Kolb & Stehle, 1996). If the standard models of evolution are correct then long-period (P_orb > 5 hrs) CVs should be typically less than 1.5 Gyr old, and their line-of-sight velocity dispersion ($\\sigma_\\gamma$) should be small. We present results from a pilot study which indicate that this postulate is indeed true. Four long-period dwarf novae (EM Cyg, V426 Oph, SS Cyg and AH Her) were observed over a complete orbit, in order that accurate radial velocities be obtained. We find values of -1.7, 5.4, 15.4 and 1.8 km/s with uncertainties of order 3 km/s, referred to the dynamical Local Standard of Rest (LSR), leading to a dispersion of ~ 8 km/s. Calculation of a 95 per cent confiden...

North, R C; Kolb, U; Dhillon, V S; Moran, C K J

2002-01-01

362

A simple global representation for second-order normal forms of Hamiltonian systems relative to periodic flows  

International Nuclear Information System (INIS)

We study the determination of the second-order normal form for perturbed Hamiltonians relative to the periodic flow of the unperturbed Hamiltonian H0. The formalism presented here is global, and can be easily implemented in any computer algebra system. We illustrate it by means of two examples: the Hénon–Heiles and the elastic pendulum Hamiltonians. (paper)

363

Output-only modal analysis of linear time-periodic systems with application to wind turbine simulation data  

Science.gov (United States)

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 in the velocity of the wind with height and changes in the aerodynamics of the blades as they pass the tower. These effects may cause parametric resonance or other unexpected phenomena, so it is important to properly characterize them so that these machines can be designed to achieve high reliability, safety, and to produce economical power. This work presents a system identification methodology that can be used to identify models for linear, periodically time-varying systems when the input forces are unmeasured, broadband and random. The methodology is demonstrated for the well-known Mathieu oscillator and then used to interrogate simulated measurements from a rotating wind turbine. The measurements were simulated for a 5 MW turbine modeled in the HAWC2 simulation code, which includes both structural dynamic and aerodynamic effects. This simulated system identification provides insights into the test and measurement requirements and the potential pitfalls, and simulated experiments such as this may be useful to obtain a set of time-periodic equations of motion from a numerical model, since a closed form model is not readily available by other means due to the way in which the aeroelastic effects are treated in the simulation code.

Allen, Matthew S.; Sracic, Michael W.; Chauhan, Shashank; Hansen, Morten Hartvig

2011-05-01

364

Optimal unit commitment of the power system in Bulgaria during the transitional period to power wholesale market  

International Nuclear Information System (INIS)

The paper presents a procedure for optimal one year unit commitment in Bulgarian electric power system during the transitional period to wholesale market, combining certain classical theoretical models with heuristic methods. Comments are made on the transition from yearly commitment to weekly and daily dispatching control. The stages of the theory and practices for results optimality

365

Assessment of Tension of the Students’ Organism Regulatory Systems during the Initial Period of Study at the University  

Directory of Open Access Journals (Sweden)

Full Text Available The article presents research results of the current functional state of students by recording the heart rate variability during the study period. Imbalance of parts of the autonomic nervous system and reactivity reduction of parasympathetic and sympathetic divisions at large number of examinees were detected.

Aiman E. Konkabaeva

2012-08-01

366

Output-only modal analysis of linear time-periodic systems with application to wind turbine simulation data  

DEFF Research Database (Denmark)

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 in the velocity of the wind with height and changes in the aerodynamics of the blades as they pass the tower. These effects may cause parametric resonance or other unexpected phenomena, so it is important to properly characterize them so that these machines can be designed to achieve high reliability, safety, and to produce economical power. This work presents a system identification methodology that can be used to identify models for linear, periodically time-varying systems when the input forces are unmeasured, broadband and random. The methodology is demonstrated for the well-known Mathieu oscillator and then used to interrogate simulated measurements from a rotating wind turbine. The measurements were simulated for a 5 MW turbine modeled in the HAWC2 simulation code, which includes both structural dynamic and aerodynamic effects. This simulated system identification provides insights into the test and measurement requirements and the potential pitfalls, and simulated experiments such as this may be useful to obtain a set of time-periodic equations of motion from a numerical model, since a closed form model is not readily available by other means due to the way in which the aeroelastic effects are treated in the simulation code.

Allen, Matthew S.; Sracic, Michael W.

2011-01-01

367

The EPICS based plant control system for KSTAR-First operation period implementations and experiences  

International Nuclear Information System (INIS)

After successful achieving first plasma, Korea Superconducting Tokamak Advanced Research (KSTAR) is now preparing second operation that includes power supplies with full power operation and more diagnostic systems. During first campaign the Experimental Physics and Industrial Control System (EPICS) was adopted as a control middleware of the KSTAR control system showed stable and reliable results and did not reveal any significant system failures. The EPICS based plant control system is used for data acquisition, data archiving and data visualization and is interfaced with Central Control System (CCS). A plant control system requires an EPICS Input Output Controller (IOC) and its own DAQ system. During the first operation the EPICS based control systems were mainly used slow data acquisition at a rate less than 10 Hz. The hardware platforms were Programmable Logic Controller (PLC) and PCI eXtensions for Instrumentation (PXI). In this paper we will describe following items: the details of control function, implementation of each plant control system, operation results and analysis, focusing on the Tokamak Monitoring System (TMS), the Vacuum Monitoring System (VMS), the Current Lead System (CLS), the Helium Distribution System (HDS), and the Heating Systems.

368

Non-trivial, non-negative periodic solutions of a system of singular-degenerate parabolic equations with nonlocal terms  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We study the existence of non-trivial, non-negative periodic solutions for systems of singular-degenerate parabolic equations with nonlocal terms and satisfying Dirichlet boundary conditions. The method employed in this paper is based on the Leray-Schauder topological degree theory. However, verifying the conditions under which such a theory applies is more involved due to the presence of the singularity. The system can be regarded as a possible model of the interactions of ...

Fragnelli, Genni; Mugnai, Dimitri; Nistri, Paolo; Papini, Duccio

2013-01-01

369

Orbital periods of cataclysmic variables identified by the SDSS. V. VLT, NTT and Magellan observations of nine equatorial systems  

CERN Document Server

We present VLT and Magellan spectroscopy and NTT photometry of nine faint cataclysmic variables (CVs) which were spectroscopically identified by the SDSS. We measure orbital periods for five of these from the velocity variations of the cores and wings of their Halpha emission lines. Four of the five have orbital periods shorter than the 2-3 hour period gap observed in the known population of CVs. SDSS J004335.14-003729.8 has an orbital period of Porb = 82.325 +/- 0.088 min; Doppler maps show emission from the accretion disc, bright spot and the irradiated inner face of the secondary star. In its light curve we find a periodicity which may be attributable to pulsations of the white dwarf. SDSS J163722.21-001957.1 has Porb = 99.75 +/- 0.86 min. By combining this new measurement with a published superhump period we estimate a mass ratio of 0.16 and infer the physical properties and orbital inclination of the system. For SDSS J164248.52+134751.4 we find Porb = 113.60 +/- 1.5 min. The Doppler map of this CV shows ...

Southworth, John; Marsh, T R; Torres, M A P; Steeghs, D; Hakala, P; Copperwheat, C M; Aungwerojwit, A; Mukadam, A

2008-01-01

370

18 CFR 301.4 - Exchange Period Average System Cost determination.  

Science.gov (United States)

...Bonneville will use the following approach: (1) Use the RHWM System Resources as determined in the Tiered Rates Methodology (TRM) process. (2) Determine the RHWM Exchange Load. (3) Calculate the Utility's Contract System Cost as described...

2010-04-01

371

Orbital periods of cataclysmic variables identified by the SDSS - V. VLT, NTT and Magellan observations of nine equatorial systems  

Science.gov (United States)

We present Very Large Telescope (VLT) and Magellan spectroscopy and New Technology Telescope photometry of nine faint cataclysmic variables (CVs) which were spectroscopically identified by the Sloan Digital Sky Survey (SDSS). We measure orbital periods for five of these from the velocity variations of the cores and wings of their H? emission lines. Four of the five have orbital periods shorter than the 2-3h period gap observed in the known population of CVs. SDSS J004335.14-003729.8 has an orbital period of Porb = 82.325 +/- 0.088min Doppler maps show emission from the accretion disc, bright spot and the irradiated inner face of the secondary star. In its light curve, we find a periodicity which may be attributable to pulsations of the white dwarf. SDSS J163722.21-001957.1 has Porb = 99.75 +/- 0.86min. By combining this new measurement with a published superhump period, we estimate a mass ratio of q ~ 0.16 and infer the physical properties and orbital inclination of the system. For SDSS J164248.52+134751.4, we find Porb = 113.60 +/- 1.5min. The Doppler map of this CV shows an unusual brightness distribution in the accretion disc which would benefit from further observations. SDSS J165837.70+184727.4 had spectroscopic characteristics which were very different between the SDSS spectrum and our own VLT observations, despite only a small change in brightness. We measure Porb = 98.012 +/- 0.065min from its narrow H? emission line. Finally, SDSS J223843.84+010820.7 has a comparatively longer period of Porb = 194.30 +/- 0.16min. It contains a magnetic white dwarf and, with g = 18.15, is brighter than the other objects studied here. These results continue the trend for the fainter CVs identified by the SDSS to be almost exclusively shorter period objects with low mass transfer rates.

Southworth, John; Gänsicke, B. T.; Marsh, T. R.; Torres, M. A. P.; Steeghs, D.; Hakala, P.; Copperwheat, C. M.; Aungwerojwit, A.; Mukadam, A.

2008-12-01

372

Effective tunneling coefficient of a coupled double-well system modulated by anharmonic periodic potentials  

Science.gov (United States)

We numerically study coherent tunneling oscillations of the particles between two levels in a double-well potential in the presence of anharmonic periodic potentials. Extremely short driving pulses modify the tunneling coefficient to ?eff=?cosA , where ? is the bare tunneling coefficient without the driving field and A is the pulse area of the driving wave form. The modulation amplitude of the ?eff gradually decreases as the driving wave form becomes broad and is given by ?eff=?J0(A) for the sinusoidal modulation, where J0(x) denotes the ordinary Bessel function of order zero. Theoretical derivation of the effective tunneling coefficient ?eff=?cosA is also shown for a periodic ? kick with alternating sign by means of the transfer matrix formula.

Tsukada, N.; Yoshida, H.; Suzuki, T.

2008-02-01

373

Dynamic Stability Analysis of Periodically Time-Varying Rotor System with a Transverse Crack  

Directory of Open Access Journals (Sweden)

Full Text Available Fatigue cracks may appear in horizontal rotating machinery due to periodic stresses imposed to its shaft. The investigation of stability behavior of cracked rotors can lead to proper diagnosis of machinery and to prevent possible accidents caused by the rotor failure. In this study, the dynamic stability of a rotor with a transverse crack is investigated. Models of both open and breathing cracks are developed and then used in the model of a cracked Jeffcot (de Laval rotor. The stability of rotor motion equations represented by differential equations with periodic coefficients is investigated using Floquet theory. While both crack models show instability regions around the first un-damped frequency, sub-harmonic regions are predicted by the breathing crack models. Compared to perturbation methods frequently used to determine the stability regions, the transition matrix approach used in this study can be applied to complex models of rotors and consequently may help in the identification of cracks in rotating machinery.

Costin D. Untaroiu

2011-07-01

374

Optimization of congested traffic flow in systems with a localized periodic inhomogeneity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 d...

Tomer, Elad; Safonov, Leonid; Madar, Nilly; Havlin, Shlomo

2001-01-01

375

Noise-Induced Phase Space Transport in Time-Periodic Hamiltonian Systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Orbits in a three-dimensional potential subjected to periodic driving, V(x^i,t)=[1+m_0 sin(omega t) V_0(x^i), divide naturally into two types, regular and chaotic, between which transitions are seemingly impossible. The chaotic orbits divide in turn into two types, apparently separated by entropy barriers, namely `sticky' orbit segments, which are `locked' to the driving frequency and exhibit little systematic energy diffusion, and `wildly' chaotic segments, which are not so...

Terzic, Balsa; Kandrup, Henry E.

2003-01-01

376

The system of haemostasis of hens under low-level gamma-radiation in embryonal period  

International Nuclear Information System (INIS)

Exposure of hen's eggs to irradiation by doses 0.05-1.66 Gy (dose rate 2.56 x 10-4 Gy/s) in early embryonal period (1st day of incubation of eggs) essentially affect on indices of functional state of haemostasis sysem of two-month aged individuals, except the activation of contact phase of blood coagulation, in which a hypercoagulation shift within normal fluctuations has been noted

377

Dynamic Stability Analysis of Periodically Time-Varying Rotor System with a Transverse Crack  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fatigue cracks may appear in horizontal rotating machinery due to periodic stresses imposed to its shaft. The investigation of stability behavior of cracked rotors can lead to proper diagnosis of machinery and to prevent possible accidents caused by the rotor failure. In this study, the dynamic stability of a rotor with a transverse crack is investigated. Models of both open and breathing cracks are developed and then used in the model of a cracked Jeffcot (de Laval) rotor. The stability of r...

Untaroiu, Costin D.; Alexandrina Untaroiu; Mihail Boiangiu

2011-01-01

378

Sistemas de tutoramento e épocas de transplante de physalis / Periods replanting and training systems of cape-gooseberry  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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 adequad [...] os 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. Abstract in english 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 qu [...] ality 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, 21/11/2007 and period 2, 15/01/2008). Plants were trained under four systems (inverted "V" system, triangular system, vertical system using bamboo or vertical system using polypropylene cord), similarly to the tomato culture. Experimental design adopted was a complete randomized block in a 2x4 factorial (replant period x training system) with three replications of ten plants each. The variables analyzed were: increment of length and section area of the main branch, section area of the main branch, yield and yield efficiency. It was evidenced that the first period of replant associated to the training systems inverted "V" and triangular improved the agronomical performance of cape-gooseberry plants.

Cláudia Simone Madruga, Lima; Michel Aldrighi, Gonçalves; Zeni Fonseca Pinto, Tomaz; Andrea De Rossi, Rufato; José Carlos, Fachinello.

2472-24-01

379

Sistemas de tutoramento e épocas de transplante de physalis Periods replanting and training systems of cape-gooseberry  

Directory of Open Access Journals (Sweden)

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, 21/11/2007 and period 2, 15/01/2008. Plants were trained under four systems (inverted "V" system, triangular system, vertical system using bamboo or vertical system using polypropylene cord, similarly to the tomato culture. Experimental design adopted was a complete randomized block in a 2x4 factorial (replant period x training system with three replications of ten plants each. The variables analyzed were: increment of length and section area of the main branch, section area of the main branch, yield and yield efficiency. It was evidenced that the first period of replant associated to the training systems inverted "V" and triangular improved the agronomical performance of cape-gooseberry plants.

Cláudia Simone Madruga Lima

2010-12-01

380

Chaos in driven Alfvén systems: unstable periodic orbits and chaotic saddles  

Directory of Open Access Journals (Sweden)

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.

A. C.-L. Chian

2007-01-01

 
 
 
 
381

Progress report of the CEC project Rodos system development. Period: 1 september 92-31 august 93; Rapport d`avancement du projet europeen Rodos ``developpement du systeme``. Periode du 1er septembre 1992 au 31 aout 1993  

Energy Technology Data Exchange (ETDEWEB)

Within the context of the Radioprotection program of the CEC, the RODOS project (Real-time On-line DecisiOn Support system) aims at the development of a decision support system for nuclear emergencies. RODOS involves 22 research teams, divided in 4 sub-projects: `Meteorology and Atmospheric Dispersion, `System Development`, `Decision Aiding Techniques`. The fourth sub-project is a Joint Study Project of the Agreement between CEC ad the CIS republics. EDF is working in the `System Development` sub-project and namely in the `training` group. This group aims at the creation of a specific training course for health physics managers, based on RODOS. This note reproduces the progress report of the `Development System` project. The reporting period is: September 92 - August 93. Progress bas been made within the reporting period in the: - development of data assimilation methods incorporating both monitoring data and model predictions for obtaining consistent pictures of the environmental contamination and the source term ; - improvement and extension of the modules ATSTEP-CORA (atmospheric dispersion and deposition), EMERSIM (simulation of emergency actions), ECOAMOR (exposure pathways and dose calculation) and FRODO (simulation of relocation and agricultural countermeasures) ; - preparation of training courses using RODOS as illustrative tool ; - extension of the functions of the RODOS operating system OSY, in particular of RoGIS, its geographical information system. (author). 2 figs.

Marchand, O.

1994-12-31

382

A Phase-Locked Loop Model of the Response of the Postural Control System to Periodic Platform Motion  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A phase-locked loop (PLL) model of the response of the postural control system to periodic platform motion is proposed. The PLL model is based on the hypothesis that quiet standing (QS) postural sway can be characterized as a weak sinusoidal oscillation corrupted with noise. Because the signal to noise ratio is quite low, the characteristics of the QS oscillator are not measured directly from the QS sway, instead they are inferred from the response of the oscillator to periodic motion of the ...

Schilling, Robert J.; Robinson, Charles J.

2010-01-01

383

Nonlinear stability of periodic traveling wave solutions of systems of viscous conservation laws in the generic case  

Science.gov (United States)

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.

Johnson, Mathew A.; Zumbrun, Kevin

384

Resonance and frequency-locking phenomena in spatially extended phytoplankton–zooplankton system with additive noise and periodic forces  

International Nuclear Information System (INIS)

It is known that natural systems are undeniably subject to random fluctuations, arising from either environmental variability or internal effects. In this paper, we present a spatial version of the phytoplankton–zooplankton model that includes some important factors such as external periodic forces, noise, and diffusion processes. The spatially extended phytoplankton–zooplankton system is from the original study by Scheffer (Scheffer 1991 Oikos 62 271). Our results show that the spatially extended system exhibits a resonant pattern and frequency-locking phenomena. The system also shows that the noise and the external periodic forces play a constructive role in the Scheffer's model: (i) the noise can enhance the oscillation of phytoplankton species' density and form large clusters in space when the noise intensity is within a certain interval; (ii) the external periodic forces can induce 4:1 and 1:1 frequency-locking and spatially homogeneous oscillation phenomena to appear; and (iii) resonant patterns are observed in the system when the spatial noises and external periodic forces are both turned on. Moreover, we find that the 4:1 frequency locking transforms into 1:1 frequency locking when the noise intensity is increased. In addition to elucidating our results outside the domain of Turing instability, we provide further analysis of linear stability with the help of numerical calculation using the Maple software. Significantly, oscillations are enhanced in the system when the noise term is present. These results indicate that the oceanic plankton bloom may be partly due to interplay between the stochastic factors and external forces instead of deterministic factors. These results also may help us to understand the effects arising from the undeniable susceptibility to random fluctuations in oceanic plankton bloom

385

Spectral broadening and compression of high-intensity laser pulses in quasi-periodic systems with Kerr nonlinearity  

International Nuclear Information System (INIS)

We report the results of theoretical studies and numerical simulations of optical high-power pulse compression systems based on the spectral broadening in a Kerr nonlinear medium with subsequent pulse compression in a dispersive delay line. It is shown that the effective spectral broadening requires suppressing a smallscale instability arising due to self-focusing, which is possible in quasi-periodic systems consisting of a nonlinear medium and optical relay telescopes transmitting images of the laser beam through the system. The numerical calculations have shown the possibility of broadening the spectrum, followed by 15-fold pulse compression until the instability is excited. (control of laser radiation parameters)

386

On the absence of stable periodic orbits in domains of separatrix crossings in nonsymmetric slow-fast Hamiltonian systems.  

Science.gov (United States)

We consider a two degree of freedom Hamiltonian system with one degree of freedom corresponding to fast motion and the other corresponding to slow motion. We assume that at frozen values of the slow variables there is a separatrix on the phase plane of the fast variables and there is a region in the phase space (the domain of separatrix crossings) where projections of phase points onto the plane of the fast variables repeatedly cross the separatrix in the process of evolution of the slow variables. Under rather general conditions, we prove that there are no stable periodic trajectories of any prescribed period inside the domain of separatrix crossings, except maybe for periodic trajectories passing anomalously close to the saddle point. PMID:18163768

Neishtadt, Anatoly; Vasiliev, Alexei

2007-12-01

387

IMPACT ON THE EVOLUTION OF THE INTERNATIONAL SYSTEM OF TAXATION AND CUSTOMS OF ROMANIAN MODERN AND CONTEMPORARY PERIOD (1859 - 2013  

Directory of Open Access Journals (Sweden)

Full Text Available Since the formation of the United Principalities (24/01/1859, Romania has undergone a series of profound, permanent reforms of its fundamental institutions. The international context had an influence important, often enteritis in shaping its institutions, including the system of taxes. We plan to make a brief review of taxation in modern Romania, starting from the formation of the United Principalities (1859 via the international recognition of Romania as a kingdom (1881, the formation of the National Unitary (1918 international recognition (1919 - 1921, the interwar period (1918-1939, the Second world War (1939-1945 suffered territorial losses in 1940 , the communist period (1945-1989, the post-communist period (1989-2006, will deepen in a future article pre and post EU accession in terms of fiscal and customs.

Constanta ENEA

2014-02-01

388

Design of a period batch control planning system for cellular manufacturing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study aimed at gaining insight into the main factors that have to be taken into account when designing a planning system for the co-ordination between cells in a cellular manufacturing system. In the last decades, the application of cellular manufacturing systems has become increasingly popular, both in production and service industries. The concept is known under various names: team based production, semi-autonomous groups, group technology, and so on. A change towards cellular manu...

Riezebos, Jan

2001-01-01

389

The Earth-Moon system during the Late Heavy Bombardment period  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Jorgensen, Uffe Graae; Appel, Peter W. U.; Hatsukawa, Yuichi; Frei, Robert; Oshima, Masumi; Toh, Yosuke; Kimura, Atsushi

2009-01-01

390

Quantization and Fractional Quantization of Currents in Periodically Driven Stochastic Systems II: Full Counting Statistics  

CERN Document Server

We study Markovian stochastic motion on a graph with finite number of nodes and adiabatically periodically driven transition rates. We show that, under general conditions, the quantized currents that appear at low temperatures are a manifestation of topological invariants in the counting statistics of currents. This observation provides an approach for classification of topological properties of the counting statistics, as well as for extensions of the phenomenon of the robust quantization of currents at low temperatures to the properties of the counting statistics which persist to finite temperatures.

Chernyak, Vladimir Y; Sinitsyn, Nikolai A

2011-01-01

391

Individual and Multi Vortex Pinning in Systems with Periodic Pinning Arrays  

CERN Document Server

We examine multi and individual vortex pinning in thin superconductors with periodic pinning arrays. For multi-vortex pinning we observe peaks in the critical current of equal magnitude at every matching field, while for individual vortex pinning we observe a sharp drop in the critical current after the first matching field in agreement with experiments. We examine the scaling of the critical current at commensurate and incommensurate fields for varied pinning strength and show that the depinning force at incommensurate fields decreases faster than at the commensurate fields.

Reichhardt, C; Scalettar, R T; Hoffmann, A; Schuller, I K; Schuller, Ivan K.

2001-01-01

392

Quantization and fractional quantization of currents in periodically driven stochastic systems. II. Full counting statistics.  

Science.gov (United States)

We study Markovian stochastic motion on a graph with finite number of nodes and adiabatically periodically driven transition rates. We show that, under general conditions, the quantized currents that appear at low temperatures are a manifestation of topological invariants in the counting statistics of currents. This observation provides an approach for classification of topological properties of the counting statistics, as well as for extensions of the phenomenon of the robust quantization of currents at low temperatures to the properties of the counting statistics which persist to finite temperatures. PMID:22519316

Chernyak, Vladimir Y; Klein, John R; Sinitsyn, Nikolai A

2012-04-21

393

Pilot Periodicity Based OFDM Signal Detection Method for Cognitive Radio System  

Science.gov (United States)

Cognitive Radio is an advanced enabling technology for efficient utilization of vacant spectrum due to its ability to sense the spectrum environment. Various detection methods have been proposed for spectrum sensing, which is the key function in implementing cognitive radio. However most of the existing methods put their interests in detecting TV signal and wireless microphone signals. In this paper, we explore the periodicity of the equally spaced pilot subcarriers in OFDM signal. Simulations in various fading environments show that the proposed cyclostationarity based detection method works well for OFDM signal.

Sohn, Sung Hwan; Han, Ning; Zheng, Guanbo; Kim, Jae Moung

394

SYSTEM OF EDUCATION DURING THE SANGAM PERIOD: A PHENOMENA FOR SOCIALAND CULTURAL INTEGRATION  

Directory of Open Access Journals (Sweden)

Full Text Available Nothing is more characteristic of the society of the ancient Tamils during the Sangam period than the prominance given to education and literary pursuits in their public thought. That there was a lofty conception of education from the very early times of the Sangam era, seems fairly certain, when we consider the general level of culture mirrored in the literature, art and social and religious conditions of the times. This fact is amply testified by N. Subramanian in his magnum opus sangam polity

P. Jeyabalakrishnan

2014-10-01

395

Progress report of the CEC project Rodos system development. Period: 1 september 92-31 august 93  

International Nuclear Information System (INIS)

Within the context of the Radioprotection program of the CEC, the RODOS project (Real-time On-line DecisiOn Support system) aims at the development of a decision support system for nuclear emergencies. RODOS involves 22 research teams, divided in 4 sub-projects: 'Meteorology and Atmospheric Dispersion, 'System Development', 'Decision Aiding Techniques'. The fourth sub-project is a Joint Study Project of the Agreement between CEC ad the CIS republics. EDF is working in the 'System Development' sub-project and namely in the 'training' group. This group aims at the creation of a specific training course for health physics managers, based on RODOS. This note reproduces the progress report of the 'Development System' project. The reporting period is: September 92 - August 93. Progress bas been made within the reporting period in the: - development of data assimilation methods incorporating both monitoring data and model predictions for obtaining consistent pictures of the environmental contamination and the source term ; - improvement and extension of the modules ATSTEP-CORA (atmospheric dispersion and deposition), EMERSIM (simulation of emergency actions), ECOAMOR (exposure pathways and dose calculation) and FRODO (simulation of relocation and agricultural countermeasures) ; - preparation of training courses using RODOS as illustrative tool ; - extension of the functions of the RODOS operating system OSY, in particular of RoGIS, its geographical information system. (author). 2 figs

396

Biophysical probing of Spartina maritima photo-system II changes during prolonged tidal submersion periods.  

Science.gov (United States)

Submergence is one of the major constrains affecting wetland plants, with inevitable impacts on their physiology and productivity. Global warming as a driving force of sea level rise, tend to increase the submersion periods duration. Photosynthesis biophysical probing arise as an important tool to understand the energetics underlying plant feedback to these constrains. As in previous studies with Spartina maritima, there was no inhibition of photosynthetic activity in submerged individuals. Comparing both donor and acceptor sides of the PSII, the first was more severely affected during submersion, driven by the inactivation of the OEC with consequent impairment of the ETC. Although this apparent damage in the PSII donor side, the electron transport per active reaction centre was not substantially affected, indicating that this reduction in the electron flow is accompanied by a proportional increase in the number of active reaction centres. These conditions lead to the accumulation of excessive reducing power, source of damaging ROS, counteracted by efficient energy dissipation processes and anti-oxidant enzymatic defences. This way, S. maritima appears as a well-adapted species with an evident photochemical plasticity towards submersion, allowing it to maintain its photosynthetic activity even during prolonged submersion periods. PMID:24630362

Duarte, B; Santos, D; Marques, J C; Caçador, I

2014-04-01

397

Electrostatic interactions in finite systems treated with periodic boundary conditions: Application to linear-scaling density functional theory  

Science.gov (United States)

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

398

Dynamic Scheduling of Skippable Periodic Tasks with Energy Efficiency in Weakly Hard Real-Time System  

CERN Document Server

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...

Baskaran, Santhi

2010-01-01

399

Periodic and Solitary Wave Solutions of Two Component Zakharov-Yajima-Oikawa System, Using Madelung's Approach  

Directory of Open Access Journals (Sweden)

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.

Anca Visinescu

2011-04-01

400

STOCHASTIC ANALYSIS OF A COMPLEX SYSTEM WITH CORRELATED WORKING AND REST PERIOD OF REPAIRMAN  

Directory of Open Access Journals (Sweden)

Full Text Available This paper deals with the stochastic analysis of a complex system with correlatedworking and rest time of repairman. The system consists of two subsystems, say A and Bconnected in series. Subsystem A consists of two identical units whereas subsystem B consists ofonly one unit. The operation of only one unit of subsystem A with subsystem B is sufficient to dothe job. The failure time distributions of the units are taken exponential while the repair timedistributions are assumed to be general. Various measures of system effectiveness useful tosystem managers are obtained by using regerative point technique. Graphical study of the systemthrough MTSF and profit function is also carried out.

Ram Kishan

2010-01-01

 
 
 
 
401

Localized Excitations of (2+1)-Dimensional Korteweg-de Vries System Derived from a Periodic Wave Solution  

International Nuclear Information System (INIS)

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.

402

The effects of phase change during the stand-by period in latent heat energy storage systems  

Energy Technology Data Exchange (ETDEWEB)

When the boundary condition causing a phase change is interrupted, the phase change process continues until the temperature distribution in the whole system becomes uniform due to the temperature gradients existing in both phases. This continuing phase change during the so called stand-by solidification period should be taken into consideration especially at the design and the simulation stages of periodically charged/discharged latent heat energy storage systems. In this work, the effect of this freezing mechanism on the position of interface is analyzed for a semi-infinite region in cartesian coordinates and for both inward and outward solidification in cylindrical coordinates. The effects of both the Stefan number and the interface position at the time of interruption on the last interface position are given in graphical forms. Also, the actual heat removal time to solidify all the phase change material encapsulated in a cylindrical container is given.

Toksoy, M.; Ilken, Z. (Dokuz Eylul Univ., Izmir (Turkey))

1991-01-01

403

Data Quality Monitoring for the ATLAS trigger System during the first data taking period of the Large Hadron Collider  

CERN Document Server

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 ...

Oliveira Damazio, Denis; The ATLAS collaboration

2013-01-01

404

Data Quality Monitoring for the ATLAS trigger System during the first data taking period of the Large Hadron Collider  

CERN Document Server

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 ...

Damazio, D O; The ATLAS collaboration

2013-01-01

405

Light curve solutions and study of roles of magnetic fields in period variations of the UV Leo system  

Directory of Open Access Journals (Sweden)

Full Text Available The solutions of photometric BV light curves for the Algol like system UV Leo were obtained using Wilson-Devinney code. The physical and orbital parameters along with absolute dimensions of the system were determined. It has been found that to best fit the V light curve of the system, assumptions of three dark spots were necessary two on the secondary and one on the primary. The absolute visual magnitudes (Mv of the individual components i.e., primary and secondary were estimated to 4.41 and 4.43, respectively, through the color curve analysis. The period analysis of the system presented elsewhere, indicated a cyclic period change of 12 yr duration, which was attributed to magnetic activity cycle, as a main cause of period variation in the system, through the Applegate mechanism. To verify the Applegate model I preformed calculations of some related parameters barrowed from Apllegate and Kalimeris. Values of all the calculated parameters were in accordance to those obtained for similar systems by Applegate. The differential magnitudes ? B and ? V, along with corresponding values of ?(B-V color index. The cyclic variations in brightness are quite clear. There are three predictions of Applegate's theory concerning effects of cyclic magnetic changes on the period variations, which can be checked through the observations, these are as follows: I The long term variations in mean brightness (at outside of eclipses and cyclic changes of orbital period, vary with the same period. II The active star gets bluer as it gets brightened and/or the brightness and color variations are to be in phase. III Changes in luminosity due to changes in quadrupole moment should be of the order 0.1 mag. All the above mentioned predictions of Applegate’s theory are verified. These results combined with cyclic character of P(E presented elsewhere and also consistency of parameters which are obtained in this paper, led me to conclude that one the main causes of period variability in UV Leo system is magnetic activity cycle (newly presented here. Since both components (G0&G2 of this system magnetically can be active, and separation of the components is relatively low (3.9Rs, the magnetic braking could also cause the period change. The magnetized star winds move outward from the star, but are twisted due to rapid rotation of star. Charged particles in the stars wind become trapped in the star's magnetic field and are dragged along the field lines .The result is angular momentum (AM transfer from the star by magnetic field to the charged particles. As the winds leave the star surface they are dragged by the magnetic field which in turn slows down the star's rotation.

D Manzoori

2009-12-01

406

Pork meat matured for different periods of time in vacuum-packaging system  

Directory of Open Access Journals (Sweden)

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.

Marina Avena Tarsitano

2014-02-01

407

Exponential stability of linear and almost periodic systems on Banach spaces  

Directory of Open Access Journals (Sweden)

Full Text Available Let $v_f(cdot, 0$ the mild solution of the well-posed inhomogeneous Cauchy problem $$ dot v(t=A(tv(t+f(t, quad v(0=0quad tge 0 $$ on a complex Banach space $X$, where $A(cdot$ is an almost periodic (possible unbounded operator-valued function. We prove that $v_f(cdot, 0$ belongs to a suitable subspace of bounded and uniformly continuous functions if and only if for each $xin X$ the solution of the homogeneous Cauchy problem $$ dot u(t=A(tu(t, quad u(0=xquad tge 0 $$ is uniformly exponentially stable. Our approach is based on the spectral theory of evolution semigroups.

Constantin Buse

2003-12-01

408

Role of staircase potential in the energy spectrum of a periodic system  

International Nuclear Information System (INIS)

An exhaustive study on the energy spectrum and the wave functions of semiconductor superlattices (SLs) in the presence of saw-tooth potential, step potential and the combined potential has been carried out. The study uses a realistic model for the SL based on the periodic crystal potential of the host crystals. The application of the staircase potential results in the formation of discrete Wannier-Stark ladder (WSL) which is experimentally exploited to achieve quantum cascade laser. The conditions for the WSL in SL has been pointed out. For the purpose of comparison, the effect of these potentials on the energy spectrum and the wave functions has also been reported for a single crystal

409

Dynamic Scheduling of Skippable Periodic Tasks With Energy Efficiency In Weakly Hard Real-Time System  

Directory of Open Access Journals (Sweden)

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-time systems. Thispaper proposes optimal slack management algorithms to make the above existing weakly hard real-timescheduling algorithms energy efficient using DVS and DPD techniques.

Santhi Baskaran

2010-12-01

410

Microwave periodic structures based on MicroElectroMechanical Systems (MEMS) and micromachining techniques  

Digital Repository Infrastructure Vision for European Research (DRIVER)

As a result of the ever growing number of functionalities and standards to be supported by communication systems, as well as the constant development of radar and imaging technologies, a key research area in the field of microwaves and millimeter waves is the achievement of reconfigurability capabilities. In recent years, the progress of MicroElectroMechanical Systems (MEMS) fabrication techniques has allowed radically challenging the performances of reconfigurable devices based on establishe...

Perruisseau-carrier, Julien; Skrivervik Favre, Anja

2008-01-01

411

Microwave periodic structures based on MicroElectroMechanical Systems (MEMS) and micromachining techniques  

Digital Repository Infrastructure Vision for European Research (DRIVER)

As a result of the ever growing number of functionalities and standards to be supported by communication systems, as well as the constant development of radar and imaging technologies, a key research area in the field of microwaves and millimeter waves is the achievement of reconfigurability capabilities. In recent years, the progress of MicroElectroMechanical Systems (MEMS) fabrication techniques has allowed radically challenging the performances of reconfigurable devices based on establishe...

Perruisseau-carrier, Julien

2007-01-01

412

Long Period Tidal Force Variations and Regularities in Orbital Motion of the Earth-Moon Binary Planet System  

CERN Document Server

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...

Avsyuk, Yu N; 10.1007/s11038-011-9381-8; 10.1007/s11038-011-9381-8

2012-01-01

413

Fuel Cell/Battery Powered Bus System. Final Report for period August 1987 - December 31, 1997  

Energy Technology Data Exchange (ETDEWEB)

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.

Wimmer, R.

1999-01-01

414

Flows of Continuous-Time Dynamical Systems with No Periodic Orbit as an Equivalence Class under Topological Conjugacy Relation  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: Flows of continuous-time dynamical systems with the same number of equilibrium points and trajectories, and which has no periodic orbit form an equivalence class under the topological conjugacy relation. Approach: Arbitrarily, two trajectories resulting from two distinct flows of this type of dynamical systems were written as a set of points (orbit. A homeomorphism which maps between these two sets is then built. Using the notion of topological conjugacy, they were shown to conjugate topologically. By the arbitrariness in selection of flows and their respective initial states, the results were extended to all the flows of dynamical s