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1

Noble gases and Mendeleev Periodic system

International Nuclear Information System (INIS)

The story of the discovery of rare gas compounds is briefly outlined in the review. On the base of energy data and simplified models the bond mechanism in these compounds is considered Regularities in changing chemical properties of rare gas compounds are revealed. The problems connected with periodicity are discu=- ssed. Achievements and perspectives of the development of the noble gases chemistry are shown

2

Additional types of periodicity in D.I. Mendeleev periodic system

International Nuclear Information System (INIS)

Published data on additional types of periodicity in the D. I. Mendeleev Periodic system are generalized. The phenomenon of secondary periodicity in subgroups of transition and rare earth elements is considered, the attempt of its theoretical explanation based on modern quantum-mechanical models is made

3

Diagram of ionization potentials of elements of the D.I. Mendeleev periodic system

International Nuclear Information System (INIS)

Ionization potentials of chemical elements with the serial numbers 71-86 and 81-102 for some electrons of 0-level and P-level, respectively, are determined. The diagram of separation energy of K-, L-, M-, N-, O-, P-, Q- electrons of outer levels for all the elements of the D.I. Mendeleev periodic system is plotted

4

New regularities in correlations of chemical properties of elements of Mendeleev's periodic system

International Nuclear Information System (INIS)

Regularities in change of chemical properties of elements depending on their position in Mendeleev's periodic system are considered. Results of investigating compositions in which elements (astatine, technetium et al.) manifest unusual valence are presented. New data on chemical properties of rare earths and actinides are generalized. Similarity of properties of the first half lanthanide and the second half actinide elements is substantiated. On the basis of predictions of atomic electron structure of the end actinide series and the following transactinide elements their possible valent states are discussed

5

Lanthanides and actinides among other groups of elements of D.I. Mendeleev's periodic system

International Nuclear Information System (INIS)

The work discusses problems of the similarity of the actinides to elements of other groups of D.I. Mendeleev's periodic system. It was shown that with respect to the change in the stability of higher and lower oxidation states with increasing atomic number of the elements, as well as the magnetic properties of the metals, an analogy is observed between the actinides and the transition elements. In a comparison of the actinides with the lanthanides, a similarity was demonstrated between the elements of the first half of the lanthanides and the second half of the actinides. In the lower oxidation states the actinides and lanthanides are analogs of the alkali and alkaline earth elements; in the tetravalent state they begin to exhibit noticeable similarity to the d-elements. Of special interest are the divalent actinide and lanthanide ions with one electron on the d-level. Exhibiting similarity to divalent elements, they from various types of cluster compounds

6

International Nuclear Information System (INIS)

Analytical forms of the system of equations, which provide a precise description, both quantitative and qualitative, of the manifestation of a correlation of the properties of groups 1-4, 8 element multitudes in the D.I. Mendeleev Periodic System, have been derived. Solutions of the system of equations forms the knowledge base for further automated studies and practical applications of metallic materials, alloys, catalysts, their carriers, composites, etc., containing elements of groups 1-4, 8

7

Mendeleev periodic law and its modern development

International Nuclear Information System (INIS)

The development history of the periodic law and its modern aspects in the light of discovering new elements are considered. Chemical properties of the latest representatives of actinides and transactinide elements are evaluated. The electronic structure of atoms of these elements is fore casted as well as their possible valence states. The expected succession in filling the electron sublevels of the Z=100 to Z=118 elements is shown and their formal analogues are listed. A supposition is made that transactinides might manifest a higher valence than their formal analogues from period 6 of the Mendeleev system

8

Mendeleev and Moseley: The Principal Discoverers of the Periodic Law

It has been asserted that as many as six persons should be regarded as "co-discoverers" of the Periodic Law (of the Chemical Elements), but it is also generally acknowledged that their respective contributions were not equal. The prevalent consensus recognizes D. I. Mendeleev's contribution as preeminent, but there is considerable disagreement about the merits of the contributions by J. L. Meyer, J. A. R. Newlands, and others. By the analysis presented in the article, the "system" proposed by Meyer in 1864 must be regarded as superior to Newlands', although Mendeleev himself did not agree with that assessment. In 1912-14 Moseley made a very significant experimental and theoretical contribution to the question, and he has a more valid claim to be regarded as a "co-discoverer" than any of Mendeleev's contemporaries.

Gorin, George

1996-06-01

9

Energetics of complex uranium halides in the light of D.I. Mendeleev Periodic System

International Nuclear Information System (INIS)

Thermochemical data for compolex uranium halides are considered using published materials in the light of the Periodic element system. The enthalpy list is compiled for complex halide production mutually correlated on the basis of the Common system of the key thermochemical data. Using the proposed method the lattice energies, enthalpies of complex anion production, average binding energies and coordination enthalpies are calculated, the regularities of their variation in the complex halide series are discussed. The calculation results are compared with experimentally determined enthalpies of complex anion production

10

Position of the lanthanides and actinides in the Mendeleev periodic system

International Nuclear Information System (INIS)

Based on the fact that the 5f elements, usually called the actinides partially exhibit only slight similarities to the lanthanides with respect to their chemical properties, their position in the periodic system is being reconsidered. Oxidation state-dependent similarities between the actinides and s, p, d, and f elements were observed. Similarities between Md1+ and alkaline earth elements, as well as between divalent lanthanides, the second half of the actinides and alkaline earth elements, are discussed. Formal analogies between actinide elements in high oxidation states and 3d elements can be seen. (orig.)

11

Analysis of physicochemical properties of the first group elements of Mendeleev's periodic system

International Nuclear Information System (INIS)

Mutual relations of physicochemical properties of the group 1 element of the Periodic System (Li -Fr, Cu, Ag, Au) were studied. Multiple interrelated changes in the values of ordered totalities of the fundamental (atomic number, density, atomic mass, atomic radii, density) and derivative (specific heat, entropy, melting and boiling points, melting and evaporation enthalpies) properties of the above element are presented. Analysis of data provided shows that systematic change in the totality of derivative properties with the change in the totality of fundamental properties occurs in the form of bands of values with upper and lower limits

12

Lanthanides and actinides - their position in the periodic system of Mendeleev

International Nuclear Information System (INIS)

In this paper the chemistry of the actinide elements is discussed with reference to their position in the periodic system. Depending in detail on the proton number of the actinide elements show great similarities in their oxidation states as well as in several other chemical properties to the elements of the d-transition group. It will be demonstrated that monovalent and divalent actinides are very similar to alcaline and alcaline earth elements whereas in the oxidation states 3+ and 4+ close analoga to the d-elements in the same oxidation states. The actinides show their individual properties especially in their highest oxidation states in which only limited similarities to d-elements exist. There is far-reaching similarity of the elements of the second half group of the actinides to the elements of the first half group of the lanthanides. (orig.)

13

The position of lanthanoids and actinoids among other groups of D.I. Mendeleev Periodic system

International Nuclear Information System (INIS)

Problems on similarity of actinoids with elements of other groups of the Periodic System are considered. Analogy between actinoids and transition elements is shown to be observed for the change in stability of high and low states of oxidation with the growth of the atomic number of an element, as well as magnetic properties of metals. Actinoids and lanthanoids are the analogs of alkali and alkali-earth elements in the low state of oxidation; they begin to show resemblance to d-elements in the tetravalent state. Bivalent actinoid and lanthanoid ions with an electron at the d-level are of special interest. Being analogous to bivalent elements, they form cluster compunds of the different type

14

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.

15

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

16

Modification and expansion of Mendeleev's periodic table

International Nuclear Information System (INIS)

The periodic table of the chemical elements has provided guidance for the discovery of many elements since its formulation as a guiding principle 125 years ago. It has misled investigators on occasion into temporary excursions along erroneous routes to new elements. Even these tortuous paths, however, have eventually led to the correct destination. It is described, the part that the periodic table has played in the discovery of the man-made elements, especially the transuranium elements, and its possible future role. (author). 7 refs., 6 figs

17

On the molybdates and tungstates of the second group elements of D.I. Mendeleev periodic system

International Nuclear Information System (INIS)

On the basis of the literature data analysed are the optimum conditions for preparation, thermodynamic and structural characteristics of orto- and oxymolybdates and tungstates of elements of the 2nd group of the periodic system. The regularities of changes of compound properties depending on the geometrical characteristics of cations are found out. The conditions of aquopolycompound preparation in 0.1 M solutions at 25+-0.1 deg C are studied. The intervals of thermal stability of para- and meta-salts are established. Considered is the character of OH- groups introduction in the composition of compounds, and shown is the coordination between the anions of aquopolymolybdates (tungstates) of the elements of the 2nd group of the periodic system and the generally adopted models for para- and metaanions

18

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

19

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

20

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

21

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)

22

International Nuclear Information System (INIS)

The dependence of atomic heat capacity of simple bo--dies on the atomic numbers of the elements in the Periodic Table has been considered at temperatures above and below the Debye characteristic temperature. In both cases considerable deviation from the Dulong and Petit rule are observed, and the dependence Csub(p) approximately f(Z) is periodic. The periodicity character is different at high and low temperatures. This may be due to the differences in dependence of harmonic and anharmonic components of heat capacity which manifest themselves below and above the Debye temperature, respectively. The role of the chemical bond character is noted in the processes of alteration of heat capacity components within the corresponding temperature ranges

23

Modern architects of the periodic system

Major discoveries, which have transformed The Periodic System of the Elements from the arrangement suggested by Mendeleev to the current configuration, are reviewed. In particular, the contributions of H. G. J. Moseley and G. T. Seaborg are described.

Ruby, Lawrence

1984-01-01

24

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

International Nuclear Information System (INIS)

Basic tendencies in the distribution of ferromagnetic (FM), antiferromagnetic (AFM) and superconductive (SC) elements in the periodic table D.I. Mendeleev are traced. FM is observed at the elements in which 3d-shell is more than half-filled (the number of 3d-electrons 6?n?8), and at the elements with 4f-shell, contained k electrons in 4f-shell, at which the sum k+n?8. Estimation of the radii of the d-, f- and p-orbitals on Slater method shown that 3d- and 4f-shells of FM are more pressing, than the ones with smaller n and k+n, and are well separated in crystal. AFM is observed at the elements, at which 3d- or 4f-shells are precisely half-filled. SC is observed in the 3d-, 4d- and 5d-elements at 1?n?x, x grows from 3 in 3d-elements to 7 in 4d- and 5d-elements, and in 7th period only at n=2 and k+n=3. Further, SC is observed at the elements, at which 3p-, 4p-, 5p- and 6p-shells contain no more than 4 electrons. In SC crystals the wave functions of external d- and p-electrons of each atom penetrate inside neighbor atoms and overlap with corresponding wave functions with smaller main quantum number than of central atom. In this case the separation of spin and charge in electron is quite possible and the charges without spin become bosons. Spins obtained magnetic moments are ordered antiparallel by two. At transfer that pair in the parallel state by magnetic field its magnetic flux from magnetic field component along of magnetic field is equal to 1 fluxon (quant eld is equal to 1 fluxon (quant of magnetic flux)

25

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

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.

Jennifer Hogan

26

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)

27

A man made elements periodic table, including every single current element not just synthetic elements can be built differently than the naturally occurring element periodic table. Implications for knowing producible elements in space travel.

Struck, J.-T.

2013-11-01

28

International Nuclear Information System (INIS)

The spectroscopic study in a balloon carried out by Mendeleev during a solar eclipse is suggested as the first 'astronautical' experiment to find new elements. Future experiments are alluded to at the end. Intervals between elements in the early versions of the Periodic Table are reviewed and in particular, the relation to the dependency of the order in which shells are filled on (n + l). The regular sequences in non-relativistic treatments are broken up when the relativistic orbitals are used to find the ground state of heavy atoms. No rule of ordering has been developed to date for relativistic atoms. (author)

29

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

Energy Technology Data Exchange (ETDEWEB)

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).

Koroleva, L; Khapaeva, T M; Lomonosov, M V, E-mail: koroleva@phys.msu.r [Moscow State University, Moscow 119992 (Russian Federation)

2009-03-01

30

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, dispotion 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).

31

Lanthanides and actinides among other groups of elements of the D.I. Mendeleev's Periodic Table

International Nuclear Information System (INIS)

The extent to which actinides are similar to other elements of the periodic table is discussed. Actinides show certain similarity with transition metals in trends in variation of stability of the highest and lowest oxidation states with increasing atomic number. Similarity between elements of the first half of the lanthanide family and those of the second half of the actinides family is demonstrated. In the lowest oxidation states, actinides and lanthanide are analogs of alkali and alkaline-earth elements, and in the tetravalent state they start to exhibit noticeable similarity with d elements. The formation of Pu(VIII) is suggested on the basis of essentially similar volatility of oxides of Os and Ru with that of Pu. Bivalent actinides and lanthanide ions with one d electron are of particular interest. Being analogs of bivalent elements, they form various types of clusters

32

International Nuclear Information System (INIS)

The atomic environment types (AETs) (coordination polyhedra) realized by each chemical element in binary compounds at the equi-atomic composition were analyzed based on a comprehensive set of literature data. The Mendeleev number (MN) (ordering number listing the chemical elements column by column through the periodic system) was successfully used to classify the chemical systems. An atomic environment type map, using as coordinates the maximum Mendeleev number versus the ratio between the minimum and the maximum Mendeleev number, sub-divided the chemical systems where different atomic environment types occur in distinct stability domains. The same maps also showed a clear separation between chemical systems where intermediate compounds form and those where no compounds form. These maps make it possible to predict the existence of compound that have not yet been investigated with a particular atomic environment

33

Energy Technology Data Exchange (ETDEWEB)

The atomic environment types (AETs) (coordination polyhedra) realized by each chemical element in binary compounds at the equi-atomic composition were analyzed based on a comprehensive set of literature data. The Mendeleev number (MN) (ordering number listing the chemical elements column by column through the periodic system) was successfully used to classify the chemical systems. An atomic environment type map, using as coordinates the maximum Mendeleev number versus the ratio between the minimum and the maximum Mendeleev number, sub-divided the chemical systems where different atomic environment types occur in distinct stability domains. The same maps also showed a clear separation between chemical systems where intermediate compounds form and those where no compounds form. These maps make it possible to predict the existence of compound that have not yet been investigated with a particular atomic environment.

Villars, P.; Cenzual, K.; Daams, J.; Chen, Y.; Iwata, S

2004-03-24

34

The slow penetration of the Mendeleev Table in the French school curricula

International Nuclear Information System (INIS)

The great influence of the Berthelot's ideas about the non existence of atoms froze the teaching of chemistry in France for quite a long time. It is only after the Second World War that the study of the atom structure appeared in school curricula. The Mendeleev periodic system that sets the relationship between chemical properties and atom structure entered the curriculum even later in 1978. The article shows that the authors of most school manuals had anticipated the change, for in 1966 all the chemistry manuals of the 6. form had a chapter dedicated to the Mendeleev table while the issue was not yet on the syllabus. (A.C.)

35

Geometrochemistry vs Soft Computing of Mendeleev's Brain.

Czech Academy of Sciences Publication Activity Database

Brno : Brno University of Technology, 2010, s. 558-564. ISBN 978-80-214-4120-0. [Mendel 2010 - International Conference on Soft Computing /16./. Brno (CZ), 23.06.2010-25.06.2010] Institutional research plan: CEZ:AV0Z20650511 Keywords : projective geometry * Law of Mass Action * Mendeleev periodic table * brain information processing * artificial neural networks * cross-ratio * incidence structures Subject RIV: BD - Theory of Information

Gottvald, Aleš

36

Energy Technology Data Exchange (ETDEWEB)

The great influence of the Berthelot's ideas about the non existence of atoms froze the teaching of chemistry in France for quite a long time. It is only after the Second World War that the study of the atom structure appeared in school curricula. The Mendeleev periodic system that sets the relationship between chemical properties and atom structure entered the curriculum even later in 1978. The article shows that the authors of most school manuals had anticipated the change, for in 1966 all the chemistry manuals of the 6. form had a chapter dedicated to the Mendeleev table while the issue was not yet on the syllabus. (A.C.)

Vigouroux, C.H. [42300 Roanne (France)

2012-02-15

37

International Nuclear Information System (INIS)

Reports of the XVII Mendeleev congress on general and applied chemistry, volume 2 (Kazan', 21 - 26 September, 2003) are presented. Current status and prospects of the chemical science are the subject of considerable discussion. Chemical aspects, outlook for the study and application of different substances and elements of the Periodic system in various areas, ion exchange processes, extraction procedures for separation and purification, synthesis, structure and properties of different compounds, pollution of environment are treated

38

International Nuclear Information System (INIS)

Reports of the XVII Mendeleev congress on general and applied chemistry, volume 3 (Kazan', 21 - 26 September, 2003) are presented. Current status and prospects of chemical science in the field of materials testing and nanoengineering are the subject of considerable discussion. Energetic and ecological problems of modern structural materials production, prospects for the development of ceramic structural materials, polymer nanocomposites are treated. Chemical aspects, outlook for the study and application of different substances and elements of the Periodic system in various areas of chemical science and practice are noted

39

The role of the Czech chemists in reception and dissemination of the periodic system in Europe.

Czech Academy of Sciences Publication Activity Database

Budapest : MKE, 2009. s. 40. ISBN 978-963-9319-96-7. [International conference on the history of chemistry. Consumers and experts. The uses of chemistry ( and alchemy) /7./. 02.08.2009-05.08.2009, Sopron] Institutional research plan: CEZ:AV0Z80630520 Keywords : D.I. Mendeleev * B. Brauner * periodic system of elements * history of chemistry * history of Czech chemistry Subject RIV: AB - History

Štrbá?ová, So?a

40

International Nuclear Information System (INIS)

Interrelations of the values of physicochemical properties of the D.I. Mendeleev Periodic System group one elements (H, Li, Na, K, Rb, Cs, Fr), which are regularly pronounced in the form of mathematical ratios of the values of properties in diverse qualitative and quantitative combinations, permitting an obvious and accurate evaluation of a given variable on the values of other properties, have been ascertained. Systematic interrelations reveal the role, value, degree of effect of each property value on the values of other properties in the given combination. 14 refs., 2 tabs

41

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

42

International Nuclear Information System (INIS)

Reports of the XVII Mendeleev congress on general and applied chemistry (Kazan', 21 - 26 September, 2003) are presented. Current status and prospects of the chemical science are the subject of considerable discussion. Chemical aspects, outlook for the study and application of different substances and elements of the Periodic system in various areas: from preparation of functional materials to islands of stability in the field of unknown superheavy elements, pollution of environment are treated. Plenary, section and stand reports collected in the volume give a good idea of achievements and prospects of the chemical science

43

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

44

On interaction character of salts in ternary system

International Nuclear Information System (INIS)

A review of almost 800 ternary systems with common anion and common cation is presented. It is determined, that liquidus configuration of those systems reflecting nature of salts interaction depends mainly on the type of binary systems, and, thus, on place of the element within the Mendeleev periodic system

45

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

46

Periodic Systems Dependent on Parameters

Directory of Open Access Journals (Sweden)

Full Text Available This paper is concerned with a periodic system dependent on parameter. We study differentiability with respect to parameters of the periodic solution of the system. Applying a fixed point theorem and the results regarding parameters for -semigroups, we obtained some convenient conditions for determining differentiability with parameters of the periodic solution. The paper is concluded with an application of the obtained results to a periodic boundary value problem.

He Min

2010-01-01

47

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.

48

International Nuclear Information System (INIS)

By the methods of PMR and infrared-spectroscopy studied are the tungstate hydrates of Mg, Li, Cd, Al, Ge, In, Ti, Ln, Hf. The PMR spectra have been taken for air-dry and partly hydrated samples in the temperature range from 93 to 295 K. In tungstate hydrates of the 2nd and 4th groups found are the distorted moleculas of H2O with the intermolecular interproton distances different from 1.53 A, namely, increased up to 2.69 A and decreased to 1.38 A. Determined is the quantitative content of OH- groups and H2O moleculas, with different interproton distance. A formula content of the compounds studied is proposed. In tungstates of the 3d group the distorted moleculas are found only in compounds with H-/Me2O distortion is confirmed by the data of infrared spectr. The process of dehydration of distorted H2O moleculas is studied

49

International Nuclear Information System (INIS)

Adsorption properties of Sokirnitsky clinoptilolite modified with implementation of the in situ oxidative polymerization of aniline on the surface of mineral particles to anions Cr(VI), Mo(VI), W(VI), P(V), As(V), and V(V) are investigated. Promising usage of the synthesized composite for the extraction and the pre-concentration of phosphate-ions in neutral, polymolybdate- and dichromate-ions in acidic, and arsenate-ions in alkaline media is shown.

50

The final elements of the Mendeleev table

International Nuclear Information System (INIS)

Over two centuries ago, chemical elements classification has witnessed several surprising variations, which we live approximately their last stages. Workers in this field are similar to runners who progressed actively at the beginning for few seconds. Then they should struggle thereafter to gain very few percentage of a second. Physicists have shown, over the past three years, unlimited patience and ingenuity towards the filling of the final empty spaces of Mendeleiev table, especially that created elements usually disappear after its formation in about a millisecond time period. Identification of new elements is similar to police investigation, and we find here that the family of strange behavior and accurately tracked one is the trans actinides family. This article illustrates the great moments of this investigation which recently has been achieved. 16 refs., 8 figs

51

The freshwater budget of the Arctic Ocean is a key component governing the deep water formation in the North Atlantic and the global climate system. We analyzed the isotopic composition of neodymium (?Nd) in authigenic phases of marine sediments on the Mendeleev Ridge in the western Arctic Ocean spanning an estimated time interval from present to about 75 ka BP. This continuous record was used to reconstruct the ?Nd of the polar deep water (PDW) and changes in freshwater sources to the PDW through time. Three deviations in ?Nd from a long term average of -10.2 were identified at estimated 46-51, 35-39 and 13-21 ka BP. The estimated 46-51 ka BP event can be traced to bursting of ice-dammed lakes accompanying the collapse of the Barents-Kara Ice Sheet, which would have released radiogenic Nd to the eastern Arctic Ocean. The cyclonic surface circulation in the eastern Arctic Ocean must have been stronger than at present for the event to be recorded on the Mendeleev Ridge. For the 35-39 and 13-21 ka BP events, it is likely that the Laurentide Ice Sheet (LIS) supplied the unradiogenic freshwater. The configuration of the anticyclonic circulation in the western Arctic was probably similar to today or expanded eastward. Our simple mass balance calculations suggest that large amounts of freshwater were released but due to significant deep water formation within the Arctic Ocean, the effect on the formation of NADW was probably minor.

Jang, Kwangchul; Han, Yeongcheol; Huh, Youngsook; Nam, Seung-Il; Stein, Ruediger; Mackensen, Andreas; Matthiessen, Jens

2013-05-01

52

The method (algorithm BIDIMS) of multivariate objects display to bidimensional structure in which the sum of differences of objects properties and their nearest neighbors is minimal is being described. The basic regularities on the set of objects at this ordering become evident. Besides, such structures (tables) have high inductive opportunities: many latent properties of objects may be predicted on their coordinates in this table. Opportunities of a method are illustrated on ...

Zagoruiko, Andrey; Zagoruiko, Nikolay

2004-01-01

53

The Periodic Response of Periodically Perturbated Stochastic Systems

The paper introduces a new numerical characteristic of one dimensional stochastic systems. This quantity is a measure of minimal periodicity, can be detected in the process deep differential structure. The claim is that this new measure of stochasticity is also a well adapted characteristic for research of stochastic resonance phenomena.

Shahverdian, A. Yu; Apkarian, A. V.

2000-01-01

54

Periodic solutions for planar autonomous systems with nonsmooth periodic perturbations

In this paper we consider a class of planar autonomous systems having an isolated limit cycle x_0 of smallest period T>0 such that the associated linearized system around it has only one characteristic multiplier with absolute value 1. We consider two functions, defined by means of the eigenfunctions of the adjoint of the linearized system, and we formulate conditions in terms of them in order to have the existence of two geometrically distinct families of T-periodic solutions of the autonomous system when it is perturbed by nonsmooth T-periodic nonlinear terms of small amplitude. We also show the convergence of these periodic solutions to x_0 as the perturbation disappears and we provide an estimation of the rate of convergence. The employed methods are mainly based on the theory of topological degree and its properties that allow less regularity on the data than that required by the approach, commonly employed in the existing literature on this subject, based on various versions of the implicit function the...

Makarenkov, Oleg

2007-01-01

55

EDUCATION SYSTEM IN VEDIC PERIOD

Directory of Open Access Journals (Sweden)

Full Text Available The basic aim of ancient education was instilling into the minds, of peoples aspirit of being pious and religious for glory of God and good of man. The pursuit ofknowledge was a pursuit of religious values. The student had to observe strictregulations. Instruction was important, but was even more significant than teaching wasdiscipline – discipline inculcated through strict obedience to laws and regulations ofstudent life, discipline that was rooted in morality and religion A student was required togive up lust, anger, greed, vanity, conceit and over joy. Education was free. It was freebecause no student was required to pay any fees. It was free also because no outsideagency could interfere in the matters of education. There was perfect autonomy. Noexternal authority no external beneficiary, no politics was permitted to enter the schoolor college system. A student had to pay nothing in return for education he received in aGurukul. The inculcation of civic virtues and social values was an equally importantobjective of education in India. The Brahmachari after his education in the Gurukulaswent back to the society to serve the rich and the poor, to relieve the diseased and thedistressed.

R.B.KOKATANUR

2013-05-01

56

Phase Splitting for Periodic Lie Systems

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; Vorobjev, Yurii

2009-01-01

57

Localized States in Periodically Forced Systems

The theory of stationary spatially localized patterns in dissipative systems driven by time-independent forcing is well developed. With time-periodic forcing, related but time-dependent structures may result. These may consist of breathing localized patterns, or states that grow for part of the cycle via nucleation of new wavelengths of the pattern followed by wavelength annihilation during the remainder of the cycle. These two competing processes lead to a complex phase diagram whose structure is a consequence of a series of resonances between the nucleation time and the forcing period. The resulting diagram is computed for the periodically forced quadratic-cubic Swift-Hohenberg equation, and its details are interpreted in terms of the properties of the depinning transition for the fronts bounding the localized state on either side. The results are expected to shed light on localized states in a large variety of periodically driven systems.

Gandhi, Punit; Knobloch, Edgar; Beaume, Cédric

2015-01-01

58

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

59

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

60

Clustering of periodic orbits in chaotic systems

International Nuclear Information System (INIS)

In the framework of the semiclassical approach, the universal spectral correlations in Hamiltonian systems with classical chaotic dynamics can be attributed to the systematic correlations between the actions of periodic orbits which (up to the switch in the momentum direction) pass through approximately the same points of the phase space. By considering symbolic dynamics of the system one can introduce a natural ultrametric distance between periodic orbits and organize them into clusters of orbits approaching each other in the phase space. We study the distribution of cluster sizes for the baker's map in the asymptotic limit of long trajectories. This problem is equivalent to the one of counting degeneracies in the length spectrum of the de Bruijn graphs. Based on this fact, we derive the probability Pk that k randomly chosen periodic orbits belong to the same cluster. Furthermore, we find asymptotic behaviour of the largest cluster size |Cmax| and derive the probability P(t) that a random periodic orbit belongs to a cluster smaller than t|Cmax|, t ? [0, 1]. (paper)

61

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

62

Scaling concepts in periodically modulated noisy systems

International Nuclear Information System (INIS)

We show that scaling arguments are very useful to analyze the dynamics of periodically modulated noisy systems. Information about the behavior of the relevant quantities, such as the signal-to-noise ratio, upon variations of the noise level, can be obtained by analyzing the symmetries and invariances of the system. In this way, it is possible to predict diverse physical manifestations of the cooperative behavior between noise and input signal, as for instance stochastic resonance, spatiotemporal stochastic resonance, and stochastic multiresonance. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

63

Close binary systems of short period

International Nuclear Information System (INIS)

Information on 406 close binary systems with periods less than 1.5 days for which the primary is of known spectral type, is assembled from recent sources. The organization of the presentation depends on a light curve descriptor which takes the values EA1, EA2, EA3, EB, EW and E 11. Within these groups the distribution in the spectral type (s):period (P) plane is examined. An additional distribution of this kind is presented for 311 EA2 candidate stars (evolved Algols), with periods of up to 15 days. Recent empirical information on Main Sequence stars is presented for comparison, and the condition that a Main Sequence component of a binary system be in 'contact' with its surrounding Roche lobe provides an interesting discriminant in relation to the (s:P) distributions of the different light curve groups. Certain anomalous cases come to light. Concerning the EW (W UMa) group, detailed investigation of a particular case reveals the extent of parameter indeterminacy. A compelling case for 'contact' can only be found among the accumulation which occurs at later spectral type. A recommendation is made for a simple but more quantitative means of defining light curve type. Such a parameter could be of considerable significance in relation to statistical tests of binary evolution theory. (Auth.)

64

Evolution of ultrashort period binary systems

International Nuclear Information System (INIS)

A discussion is presented concerning the results of detailed evolutionary calculations in which a very low mass and hydrogen-depleted semiattached binary star containing a collapsed object can reach an exceptionally short orbital period while sustaining a relatively high mass transfer rate. The observed properties of such systems can be understood under the assumption that they contain moderately to severely hydrogen-defficient secondary stars that are neither fully degenerate nor burning He. It is noted that for extremely hydrogen-depleted stars, the assumption of chemical homogeneity becomes untenable. Attention is given to the binary systems 4U 1626-67, 4U 1916-05, and G61-29. 51 references

65

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

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

66

An Application-Oriented Periodic Table of the Elements.

A brief history of several of the early forms of the periodic table of the elements are discussed including those of Mendeleev, Meyer, Hubbard, Gmelin, Von Antropoff, and Strong. A more every-day-life form of the table is presented. (CW)

Bouma, J.

1989-01-01

67

On periodic orbits in discrete-time cascade systems

Directory of Open Access Journals (Sweden)

Full Text Available We present some results on existence, minimum period, number of periodic orbits, and stability of periodic orbits in discrete-time cascade systems. Some examples are presented to illustrate these results.

Xiao-Song Yang

2006-12-01

68

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.)

69

Superheavy elements in D I Mendeleev's Periodic Table

Energy Technology Data Exchange (ETDEWEB)

The results on the synthesis of new superheavy elements, synthesized in complete fusion reactions of {sup 48}Ca 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.

Oganessian, Yury Ts; Dmitriev, Sergey N [Flerov Laboratory for Nuclear Reactions, Joint Institute for Nuclear Research, Dubna, Moscow Region (Russian Federation)

2009-12-31

70

Periodic first integrals for Hamiltonian systems of Lie type

We prove the existence of a Lie algebra of first integrals for time dependent Hamiltonian systems of Lie type. Moreover, applying the Floquet theory for periodic Euler systems on Lie algebras, we show the existence of an abelian Lie algebra of periodic first integrals for periodic Hamiltonian systems. An application to the dynamics of a nonlinear oscillator is given.

Flores-Espinoza, Ruben

2010-01-01

71

Energy Technology Data Exchange (ETDEWEB)

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.)

Anon.

1997-11-01

72

Forward period analysis and the long term simulation of a periodic Hamiltonian system

The period of a Morse oscillator and mathematical pendulum system are obtained, accurate to 100 significant digits, by forward period analysis (FPA). From these results, the long-term [0, 10^60] (time unit) solutions, which overlap from the Planck time to the age of the universe, are computed reliably and quickly with a parallel multiple-precision Taylor series (PMT) scheme. The application of FPA to periodic systems can reduce the computation loops of long-term reliable sim...

Wang, Pengfei

2014-01-01

73

Periodicity and quasi-periodicity for super-integrable hamiltonian systems

International Nuclear Information System (INIS)

Classical trajectories are calculated for two Hamiltonian systems with ring shaped potentials. Both systems are super-integrable, but not maximally super-integrable, having four globally defined single-valued integrals of motion each. All finite trajectories are quasi-periodical; they become truly periodical if a commensurability condition is imposed on an angular momentum component

74

On the periodic Schr\\"odinger-Boussinesq System

We study the local and global well-posedness of the periodic boundary value problem for the nonlinear Schr\\"odinger-Boussinesq system. The existence of periodic pulses as well as the stability of such solutions are also considered.

Farah, Luiz Gustavo

2009-01-01

75

Scientific Electronic Library Online (English)

Full Text Available [...] 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

76

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

77

PSIM: Periodically shifted interleaved memory system

Energy Technology Data Exchange (ETDEWEB)

Interleaved memory schemes have been used to increase the memory bandwidth. In this paper, we propose a new interleaved memory scheme called PSIM (Periodically Shifted Interleaved Memory), which allows high memory bandwidths at the sacrifice of very small memory space. It is a stride dependent scheme where the processor utilization is 100% for most strides using a power-of-two number of memory modules. We show, analytically and then by simulation, that the efficiency of PSIM is consistently higher than not only earlier stride dependent schemes but also stride independent schemes for both short and long vector accesses.

Lee, J.Y.; Young, H.Y. [Univ. of Texas, Arlington, TX (United States)

1994-12-31

78

During the 2005 Healy-Oden Trans-Arctic Expedition (HOTRAX), core HLY0503-JPC08 was raised from the Mendeleev Ridge at the modern junction of the Beaufort Gyre and the Transpolar Drift. This core with sedimentation rates estimated on the order of 2 cm/ka is well situated to sample variations in sedimentation, and thus circulation patterns during the Quaternary. Some characteristic features such as a distinctive change in lithology and prominent IRD layers provide the basis for correlation with previously developed stratigraphies. This overall correlation is confirmed by 1 cm post-cruise diffuse spectral reflectance measurements generated using a Minolta CM-2600d spectrophotometer. Downcore analysis of principle components extracted from the DSR data indicate an inverse correlation between smectite-chlorite which reaches maxima during interglacial/interstadial intervals when sediment Mn is also high, and illite and goethite which reach maxima during glacial intervals when sediment Mn is low. These glacial-interglacial cycles are also evident in elemental composition measured using a handheld, Innov-X Alpha series XRF analyzer which we employ on Arctic sediment for the first time. Estimates of sediment Mn content inferred by diffuse spectral reflectance agree well with XRF based measurements. We observe three distinct end-members based on physical properties and elemental composition. Low density, fine- grained, glacial sediment exhibit low Mn, low Sr, and high Rb values, and thus a high Rb/Sr ratio. Moderately sandy interglacial sediment exhibits high Mn, high Sr, and low Rb values, while sediment from the transitions in to and out of glacial periods are marked by prominent spikes in density, coarse grains, and Zr concentration. Elevated Rb/Sr ratios during glacial periods may result from the re-suspension of fine-grained sediment previously deposited on the outer shelf during higher sea level, and/or by discharge from proglacial lakes. The increase in grain-size accompanied by lows in the Rb/Sr ratio during interglacial/interstadial conditions provides a proxy for fluvial sediment transport and sea-ice rafting from inner shelf environments. Zr spikes mark IRD events corresponding to ice-sheet instabilities. Because the Zr spikes are generally not associated with elevated Ca, a proxy for detrital carbonate, we infer that these spikes represent predominantly iceberg-rafted sediment of Eurasian origin, whereas three distinct Ca maxima indicate prominent iceberg events originating from the Laurentide ice sheet.

Ortiz, J. D.; Polyak, L.; Adler, R.; Jakobsson, M.; Darby, D.

2007-12-01

79

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

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

80

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

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

81

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

82

Periodic orbits of nonscaling Hamiltonian systems from quantum mechanics

International Nuclear Information System (INIS)

Quantal (E,?) plots are constructed from the eigenvalues of the quantum system. We demonstrate that these representations display the periodic orbits of the classical system, including bifurcations and the transition from stable to unstable

83

Robustness analysis of multirate and periodically time varying systems

A new method for analyzing the stability and robustness of multirate and periodically time varying systems is presented. It is shown that a multirate or periodically time varying system can be transformed into an equivalent time invariant system. For a SISO system, traditional gain and phase margins can be found by direct application of the Nyquist criterion to this equivalent time invariant system. For a MIMO system, structured and unstructured singular values can be used to determine the system's robustness. The limitations and implications of utilizing this equivalent time invariant system for calculating gain and phase margins, and for estimating robustness via singular value analysis are discussed.

Berg, Martin C.; Mason, Gregory S.

1991-01-01

84

Almost Periodic Dynamics of Perturbed Infinite-Dimensional Dynamical Systems

This paper is concerned with the dynamics of an infinite-dimensional gradient system under small almost periodic perturbations. Under the assumption that the original autonomous system has a global attractor given as the union of unstable manifolds of a finite number of hyperbolic equilibrium solutions, we prove that the perturbed non-autonomous system has exactly the same number of almost periodic solutions. As a consequence, the pullback attractor of the perturbed system i...

Wang, Bixiang

2011-01-01

85

In 2004, the NBP-0401 cruise to the western Ross Sea, found a large field of pockmarks to the north and west of Franklin Island. The pockmarks ranged in size up to 300 m or more in diameter and are up to 30 m deep. The pockmarks are generally circular and are found in a partially surveyed 3,000 km2 region at water depths ranging from 450 m to 510 m. The pockmarks were most concentrated in an area of approximately 400 km2 where they cover as much as 20% of the seafloor. About 50 km to the west of the heavily pockmarked area, a series of seafloor constructions, up to 5 km in diameter and 120 m high were found in water depths of 490 m to 520 m. Again, ice conditions precluded a complete survey but it is believed the circular features may be carbonate mounds very similar in size and water depth to the ones found by Shannon et al. (2007) in the Porcupine Bight region, offshore Ireland. In 2006, the HLY-0602 cruise undertook a seismic refraction experiment along the Mendeleev Ridge in the Arctic ocean. In the course of the experiment, two to three multibeam lines were run approximately along the crest of the ridge from 76° 40'N to 78° 50'N. On HLY-0503, pockmarks were found in the vicinity of 78° 15'N including one extraordinary cluster of pockmarks at 78° 20'N which were cored on HLY-0602. Three gravity cores taken within pockmarks recovered a significant shell hash in the upper 1 cm but carbon analysis on the shells did not reveal any evidence of chemosynthetic origin for the mollusks. Cores taken along the ridge but away from pockmarks had at most a single shell in the upper 1 cm. Shells were not found below the surface of the cores. Pockmarks along the Mendeleev Ridge are found at depths from 820 m to an extraordinary feature at a depth of ~1420 M. This collapse? feature is 10 km by 5 km with a series of pockmarks in its deepest part. The major feature itself has a central depth of 1480 m but pockmarks withing the feature are as deep as 1520 m at their individual centers. There are additional concentrations of pockmarks along the spine of the Mendeleev Ridge at depths between the two mentioned above, with clusters at 889-996 m, 1030-1182 m, and 1260 m. There are regions of the ridge without significant concentrations of pockmarks but it is unknown if this is a result of our very sparse survey or some other factor. An attempt will be made to estimate possible methane outgassing if it can be assumed that the pockmarks observed on HLY-0602 represent recent phenomena. Shannon, P.M., McDonnell, A., and Bailey, W.R., 2007. The evolution of the Porcupine and Rockall basins, offshore Ireland: the geological template for carbonate mound development, Int J Earth Sci (Geol Rundsch) 96: 21-35.

Lawver, L. A.; Hornbach, M. J.; Davis, M. B.; Brumley, K.; Phillips, R. L.

2008-12-01

86

Phase delay effect in a thermally homogeneous system heated periodically

International Nuclear Information System (INIS)

The response of a thermally homogeneous system to a periodical heat inflow was studied. The results of the calculations and the experiment proved that the system's temperature changed periodically with a certain phase delay ? relative to the stimulus (heat influx) and dependent on the period Th and the system's relaxation time ?, according to the equation tan ?=2??, where ?=2?/Th. This relationship can be used for determination of ? and the heat capacity of the system. The simple theory and experiment is a good example for understanding other relaxing processes of the exponential form and may be helpful to physics teachers at university level. (author)

87

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

88

Periodical Solutions of Poisson-Gradient Dynamical Systems with Periodical Potential

The main purpose of this paper is the study of the action that produces Poisson-gradient systems and their multiple periodical solutions. The Section 1 establishes the basic tools. The section 2 underlines conditions in which the action $\\phi (u) = \\displaystyle\\displaystyle\\int_{T_{0}}[ \\displaystyle% \\displaystyle{1/2}| \\displaystyle\\displaystyle\\frac{\\partial u}{% \\partial t}| ^{2}+F(t,u(t)) ] dt^{1}\\wedge >...\\wedge dt^{p}$, that produces the Poisson-gradient systems, is continuous, and some conditions in which the general action $\\phi (u) = \\displaystyle\\displaystyle\\int_{T_{0}}L(t,u(t), \\displaystyle\\displaystyle\\frac{\\partial u}{\\partial t}(t)) dt^{1}\\wedge >...\\wedge dt^{p}$ is continuously differentiable. The Section 3 studies the multiple periodical solutions of a Poisson-gradient system in the case when the potential function $F$ has a spatial periodicity.

Udriste, C; Udriste, Constantin; Duca, Iulian

2005-01-01

89

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

90

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

91

Periodic solutions of nonautonomous differential systems modeling obesity population

International Nuclear Information System (INIS)

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.

92

Code period effects in DS-CDMA systems

Code period effects in direct sequence code division multiple access (DS-CDMA) systems are investigated. It is shown that the improvement in the signal-to-interference ratio (SIR) achieved in the spread spectrum receiver is limited by a saturation value proportional to the code period.

Giubilei, R.

1995-03-01

93

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)

94

Periodicity of a class of nonlinear fuzzy systems with delays

International Nuclear Information System (INIS)

The well known Takagi-Sugeno (T-S) model gives an effective method to combine some simple local systems with their linguistic description to represent complex nonlinear dynamic systems. By using the T-S method, a class of local nonlinear systems having nice dynamic properties can be employed to represent some global complex nonlinear systems. This paper proposes to study the periodicity of a class of global nonlinear fuzzy systems with delays by using T-S method. Conditions for guaranteeing periodicity are derived. Examples are employed to illustrate the theory.

95

Periodicity of a class of nonlinear fuzzy systems with delays

Energy Technology Data Exchange (ETDEWEB)

The well known Takagi-Sugeno (T-S) model gives an effective method to combine some simple local systems with their linguistic description to represent complex nonlinear dynamic systems. By using the T-S method, a class of local nonlinear systems having nice dynamic properties can be employed to represent some global complex nonlinear systems. This paper proposes to study the periodicity of a class of global nonlinear fuzzy systems with delays by using T-S method. Conditions for guaranteeing periodicity are derived. Examples are employed to illustrate the theory.

Yu Jiali [Computational Intelligence Laboratory, School of Computer Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054 (China)], E-mail: yujiali@uestc.edu.cn; Yi Zhang [Computational Intelligence Laboratory, School of Computer Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054 (China)], E-mail: zhangyi@uestc.edu.cn; Zhang Lei [Computational Intelligence Laboratory, School of Computer Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054 (China)], E-mail: leilazhang@uestc.edu.cn

2009-05-15

96

Jumping particle model. Period doubling cascade in an experimental system

An experimental model of a modification of the Fermi acceleration problem is described. Evidence is presented for three consecutive bifurcations on the period doubling route of the system from regular to chaotic behaviour.

Pieran?ski, P.

1983-01-01

97

A family of Nikishin systems with periodic recurrence coefficients

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 li...

Delvaux, Steven; Garci?a, Abey Lo?pez; Lagomasino, Guillermo Lo?pez

2011-01-01

98

Inverse crystallization if Abrikosov vortex system at periodic pinning

The vortex system in the quasi-two-dimensional HTSC plate is considered in the case of the periodic pinning. The M(H) magnetization curves by various values of the external magnetic field and different temperatures are calculated through the Monte Carlo method. It is shown that in the case of the periodic pinning the crystallization of the vortex system is possible by the temperature increase. A number of peculiarities conditioned by the impact of the pinning centers periodic lattice are identified on the magnetization curves. The pictures of the vortex distribution corresponding to various points on the M(H) curve are obtained

Zyubin, M V; Kashurnikov, V A

2002-01-01

99

New serial time codes for seismic short period and long period data acquisition systems

International Nuclear Information System (INIS)

This paper discusses a new time code for time indexing multichannel short period (1 to 25 hz) seismic event data recorded on a single track of magnetic tape in digital format and discusses its usefulness in contrast to Vela time code used in continuous analog multichannel data recording system on multitrack instrumentation tape deck. This paper also discusses another time code, used for time indexing of seismic long period (DC to 2.5 seconds) multichannel data recorded on a single track of magnetic tape in digital format. The time code decoding and display system developed to provide quick access to any desired portion of the tape in both data recording and repro duce system is also discussed. (author). 7 figs

100

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

101

Localization of periodic orbits of polynomial systems by ellipsoidal estimates

International Nuclear Information System (INIS)

In this paper we study the localization problem of periodic orbits of multidimensional continuous-time systems in the global setting. Our results are based on the solution of the conditional extremum problem and using sign-definite quadratic and quartic forms. As examples, the Rikitake system and the Lamb's equations for a three-mode operating cavity in a laser are considered

102

Dynamical localization for two-level systems periodically driven

International Nuclear Information System (INIS)

Here, we consider a two-level system driven by an external periodic field. We show that the coherent destruction of tunnelling, as proved by Grossmann and co-workers (1991 Phys. Rev. Lett. 67 516; 1992 Europhys. Lett. 18 571) in the case of a monochromatic field, also appears for any periodic driving field given by an even regular function with zero mean value and satisfying a technical condition on the zeros of this function. (letter to the editor)

103

Period change of the eclipsing binary system CQ Cep

International Nuclear Information System (INIS)

The analysis of period changes in the eclipsing Wolf-Rayet binary system CQ Cep (WN+O7, p?1d.64) is carried out using photographic and photoelectric observations during 1899-1985. The modified Hertzshprung method for calculation of O - C values has been used. It is concluded that the period of CQ Cep is decreasing in the time interval of 1899-1985 on an average at the rate of p=-0.014±0.004 s/year

104

Truncation of Periodic Image Interactions for Confined Systems

First principles methods based on periodic boundary conditions are used extensively by materials theorists. However, applying these methods to systems with confined electronic states entails the use of large unit cells in order to avoid artificial image interactions. We present a general approach for truncating the Coulomb interaction that removes image effects directly and leads to well converged results for modest-sized periodic cells. As an illustration, we find the lowes...

Ismail-beigi, Sohrab

2006-01-01

105

The period ratio distribution of Kepler's candidate multiplanet systems

We calculate and analyse 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 (MMRs), 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-systems of sub-Neptune/super-Earth planets with relatively short orbital periods.

Steffen, Jason H.; Hwang, Jason A.

2015-04-01

106

M|G|? queue systems busy period and logistics

In the M|G|? queueing systems customers arrive according to a Poisson process at rate . Each of them receives immediately after its arrival a service whose length is a positive random variable with distribution function G(.) and mean value a . An important parameter of the system is the traffic intensity . The service of a customer is independent of the services of the other customers and of the arrival process. The busy period of a queueing system begins when a customer ...

Ferreira, Manuel Alberto M.

2003-01-01

107

General approach for dealing with dynamical systems with spatiotemporal periodicities

Dynamical systems often contain oscillatory forces or depend on periodic potentials. Time or space periodicity is reflected in the properties of these systems through a dependence on the parameters of their periodic terms. In this paper we provide a general theoretical framework for dealing with these kinds of systems, regardless of whether they are classical or quantum, stochastic or deterministic, dissipative or nondissipative, linear or nonlinear, etc. In particular, we are able to show that simple symmetry considerations determine, to a large extent, how their properties depend functionally on some of the parameters of the periodic terms. For the sake of illustration, we apply this formalism to find the functional dependence of the expectation value of the momentum of a Bose-Einstein condensate, described by the Gross-Pitaewskii equation, when it is exposed to a sawtooth potential whose amplitude is periodically modulated in time. We show that, by using this formalism, a small set of measurements is enough to obtain the functional form for a wide range of parameters. This can be very helpful when characterizing experimentally the response of systems for which performing measurements is costly or difficult.

Casado-Pascual, Jesús; Cuesta, José A.; Quintero, Niurka R.; Alvarez-Nodarse, Renato

2015-02-01

108

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

109

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

110

Population Growth and Periodic Instability of the International System

From the perspective developed in this paper, it can be argued that exponential population growth resulted in the exponential decrease of the life-span of consecutive stable periods during the life-span of the European international system (1480-1945). However, it becomes evident as well that population growth as such is not a sufficient condition to generate a punctuated equilibrium dynamic in the war dynamics of the international system: other conditions and factors - and their interplay - contribute to this typical dynamic as well. From 1945 until the collapse of the Soviet Union (1991), the conditions of international system differed fundamentally from the conditions of the European international system during the period 1480-1945. It can be argued, that sooner or later a punctuated equilibrium war dynamic will resume.

Piepers, I

2006-01-01

111

Almost periodic solutions to systems of parabolic equations

Directory of Open Access Journals (Sweden)

Full Text Available In this paper we show that the second-order differential solution is 𝕃2-almost periodic, provided it is 𝕃2-bounded, and the growth of the components of a non-linear function of a system of parabolic equation is bounded by any pair of con-secutive eigenvalues of the associated Dirichlet boundary value problems.

Janpou Nee

1994-01-01

112

Periodic pulses of calcium ions in a chemical system.

By coupling the bromate-sulfite-ferrocyanide oscillating chemical reaction with the complexation of calcium ion by EDTA, we construct a system that generates periodic pulses of free Ca(2+) with an amplitude of 2 orders of magnitude and a period of ca. 20 min. These pulses may be observed either with a calcium ion-selective electrode or with Arsenazo(III) as an indicator. We describe the systematic design procedure and the properties of this first abiotic calcium-based chemical oscillator. PMID:16774201

Kurin-Csörgei, Krisztina; Epstein, Irving R; Orban, Miklós

2006-06-22

113

Generalized H2 Control Synthesis for Periodic Systems

DEFF Research Database (Denmark)

A control synthesis of periodic processes is addressed in this paper. A class of linear discrete time periodic systems with performance specified by the generalized $H_2$ operator norm, is considered. The paper proposes an LMI solution to this problem, the sufficient and necessary conditions for solvability of $H_2$ suboptimal control are stated. An algorithm for state feedback control synthesis is provided. The findings are applied for the attitude control of a satellite equipped with electro-magnetic coils, which comprises a very attractive means of attitude corrections for small low-cost spacecraft missions.

Wisniewski, Rafal; Stoustrup, Jakob

2001-01-01

114

Geometric phase and band inversion in periodic acoustic systems

The geometric-phase concept has far-reaching implications in many branches of physics. The geometric phase that specifically characterizes the topological property of bulk bands in one-dimensional periodic systems is known as the Zak phase. Recently, it has been found that topological notions can also characterize the topological phase of mechanical isostatic lattices. Here, we present a theoretical framework and two experimental methods to determine the Zak phase in a periodic acoustic system. We constructed a phononic crystal with a topological transition point in the acoustic band structure where the band inverts and the Zak phase in the bulk band changes following a shift in system parameters. As a consequence, the topological characteristics of the bandgap change and interface states form at the boundary separating two phononic crystals having different bandgap topological characteristics. Such acoustic interface states with large sound intensity enhancement are observed at the phononic crystal interfaces.

Xiao, Meng; Ma, Guancong; Yang, Zhiyu; Sheng, Ping; Zhang, Z. Q.; Chan, C. T.

2015-03-01

115

Period Changes of the Algol System SZ Herculis

New CCD photometric observations of SZ Her were obtained between February and May 2008. More than 1,100 times of minimum light spanning more than one century were used for the period analysis. We find that the orbital period of SZ Her has varied due to a combination of two periodic variations, with cycle lengths of P3 = 85.8 yr and P4 = 42.5 yr and semi-amplitudes of K3 = 0.013 days and K4 = 0.007 days, respectively. The most reasonable explanation for them is a pair of light-time-travel (LTT) effects driven by the existence of two M-type companions with minimum masses of M3 = 0.22 M? and M4 = 0.19 M?, located at nearly 2:1 mean motion resonance. Then, SZ Her is a quadruple system and the 3rd and 4th components would stay in the stable orbital resonance.

Lee, J. W.; Lee, C.-U.; Kim, S.-L.; Kim, H.-I.; Park, J.-H.; Hinse, T. C.

2012-04-01

116

O-C diagrams and period changes in stellar systems

Based on the visual inspection of all O-C diagrams available in the O-C gateway managed by the Variable stars and exoplanet section of the Czech astronomical society we present an overview of possible shapes of O-C diagrams together with discussion of possible effects causing such dependences. The nature of these effects is discussed for various types of periodic variable. We also give short remarks on interesting eclipsing systems BV Dra and BW Dra which form a visual pair and show antiparallel changes of their O-C diagrams. In addition we comment on period changes of UU Cam, and argue that it probably shows long - term Light Time Effect (LiTE) rather than sudden period change. Effects which are observable only in ultra - precise, quasi - continual measurements gathered by the Kepler satellite are discussed at the end of this contribution.

Liska, J.; Skarka, M.

2015-02-01

117

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

118

A family of Nikishin systems with periodic recurrence coefficients

International Nuclear Information System (INIS)

Suppose we have a Nikishin system of p measures with the kth generating measure of the Nikishin system supported on an interval ?k subset of R with ?k ? ?k+1 = ? 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 ?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 {Pn}n=0?, the so-called Chebyshev-Nikishin polynomials. We show that the polynomials Pn 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 ?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 {Pn}n=0?. Bibliography: 27 titles.

119

Electrostatics of solvated systems in periodic boundary conditions

Continuum solvation methods can provide an accurate and inexpensive embedding of quantum simulations in liquid or complex dielectric environments. Notwithstanding a long history and manifold applications to isolated systems in open boundary conditions, their extension to materials simulations, typically entailing periodic boundary conditions, is very recent, and special care is needed to address correctly the electrostatic terms. We discuss here how periodic boundary corrections developed for systems in vacuum should be modified to take into account solvent effects, using as a general framework the self-consistent continuum solvation model developed within plane-wave density-functional theory [O. Andreussi et al., J. Chem. Phys. 136, 064102 (2012), 10.1063/1.3676407]. A comprehensive discussion of real- and reciprocal-space corrective approaches is presented, together with an assessment of their ability to remove electrostatic interactions between periodic replicas. Numerical results for zero- and two-dimensional charged systems highlight the effectiveness of the different suggestions, and underline the importance of a proper treatment of electrostatic interactions in first-principles studies of charged systems in solution.

Andreussi, Oliviero; Marzari, Nicola

2014-12-01

120

Gap Solitons and Bloch Waves in Nonlinear Periodic Systems

We comprehensively investigate gap solitons and Bloch waves in one-dimensional nonlinear periodic systems. Our results show that there exists a composition relation between them: Bloch waves at either the center or edge of the Brillouin zone are infinite chains composed of fundamental gap solitons(FGSs). We argue that such a relation is related to the exact relation between nonlinear Bloch waves and nonlinear Wannier functions. With this composition relation, many conclusion...

Zhang, Yongping; Liang, Zhaoxin; Wu, Biao

2009-01-01

121

In the summer of 2006 we acquired a unique seismic refraction data set on the Chukchi Borderlands and Mendeleev Ridge utilizing USCGC Healy and two helicopters. The array on the Mendeleev Ridge consisted of 14 instrument sites with 12 km spacing between instruments. On every site we deployed a Sea-Ice Seismometer (S- IS) especially designed for this experiment in the ice-covered part of the Arctic Ocean. Each S-IS contained a vertical component geophone that was buried in the ice and a hydrophone that was hanging from the ice edge in the water. From the 14 instrument sites, 10 contained useful data with refracted crustal arrivals up to offsets of 40 km. Because of extensive drifting of the receivers (40 km in 5 days and containing numerous loops), and because of the irregular geometry of airgun shots due to the problems of sailing through ice-covered seas, a 3D ray-shooting code was developed to calculate ray paths within a 3D velocity model that extends along 150 km in the X- direction and along 35 km in the Y-direction. Using the velocity model proposed by Lebedeva-Ivanova et al. (2006) we observe that the maximum depth of our calculated ray paths is 11 km below sealevel. Using all the available data, the Root Mean Square (RMS) difference between observed and calculated travel-times is of the order of 500 ms. Initially a simple 1D travel-time inversion was developed to constrain the velocity structure of the basement underneath a layer of water (3D) and a layer of sediment (1D). This inversion was carried out on 2 pairs of receivers: one pair in the NNE and one more towards the SSW part of the line. Inversion of S-IS 45N-42 (NNE) results in a model with a velocity of 5.5 km s-1 at the top of the basement, slowly increasing to a velocity of 5.7 km s-1 at 3 km below the top of the basement (RMS = 117 ms). Inversion of S-IS 49-45S (SSW) results in a model with a velocity of 4.8 km s-1 at the top of the basement, increasing to a velocity of 5.9 km s-1 at 3 km below the top of the basement (RMS = 67 ms). The two resulting crustal velocity models suggest that there is a significant change in velocity along the Mendeleev Ridge: >0.5 km s-1 difference between the final models from S-IS 45N-42 and S-IS 49-45S. Rays in both models penetrate to a depth of 6.5 km. These results indicate that the Mendeleev Ridge has different crustal velocity structure in the northern and southern parts. It might also provide first proof that the Arlis plateau has a different origin and is separate from the Mendeleev Ridge. A 2D inversion is being developed which will allow inverting all the data along the Mendeleev Ridge simultaneously and which will provide us with a 2D upper-crustal velocity model along 150 km of the Mendeleev Ridge. Comparison of the resulting velocity model with the velocity structure of continental crust, thinned continental crust, oceanic crust, and other oceanic ridges will allow us to interpret the upper-crustal velocities along the Mendeleev Ridge in terms of crustal lithology and tectonic history. N.N. Lebedeva-Ivanova, Y.Y.Zamansky, A.E. Langinen, M.Y. Sorokin (2006). Seismic profiling across the Mendeleev Ridge at 82°N: evidence of continental crust. Geophys. J. Int. 165(10), 527-544.

Vermeesch, P. M.; van Avendonk, H. J.; Lawver, L. A.

2007-12-01

122

On periodic solutions and their modulations of the Manakov system

Periodic solutions of the Manakov system are studied with the aim to establish links between the recent results of Wright (Wright 2013 Physica D 264 1) and Kamchatnov (Kamchatnov 2013 Europhys. Lett. 103 60003), where one-phase solutions have been obtained by different methods and with different parameterizations. Two types of wave, which in the context of the dynamics of two-component Bose-Einstein condensates can be called density and polarization waves, are determined as particular solutions of the Manakov system. Whitham equations describing modulations of these two types of waves are obtained.

Kamchatnov, A. M.

2014-04-01

123

Semiclassical analysis of tunnelling splittings in periodically driven quantum systems

International Nuclear Information System (INIS)

For periodically driven systems, quantum tunnelling between classical resonant stability islands in phase space separated by invariant KAM curves or chaotic regions manifests itself by oscillatory motion of wavepackets centred on such an island, by mulitplet splittings of the quasienergy spectrum, and by phase space localization of the quasienergy states on symmetry-related flux tubes. Qualitatively different types of classical resonant island formation - due to discrete symmetries of the system - and their quantum implications are analysed by a (uniform) semiclassical theory. The results are illustrated by a numerical study of a driven non-harmonic oscillator. (author)

124

Periodic Solutions near Equilibria of Symmetric Hamiltonian Systems

We consider the effects of symmetry on the dynamics of a nonlinear hamiltonian system invariant under the action of a compact Lie group Gamma , in the vicinity of an isolated equilibrium: in particular, the local existence and stability of periodic trajectories. The main existence result, an equivariant version of the Weinstein-Moser theorem, asserts the existence of periodic trajectories with certain prescribed symmetries ? subset Gamma × S1, independently of the precise nonlinearities. We then describe the constraints put on the Floquet operators of these periodic trajectories by the action of Gamma . This description has three ingredients: an analysis of the linear symplectic maps that commute with a symplectic representation, a study of the momentum mapping and its relation to Floquet multipliers, and Krein Theory. We find that for some ? , which we call cyclospectral, all eigenvalues of the Floquet operator are forced by the group action to lie on the unit circle; that is, the periodic trajectory is spectrally stable. Similar results for equilibria are described briefly. The results are applied to a number of simple examples such as Gamma = SO(2), O(2), Zn, Dn, SU(2); and also to the irreducible symplectic actions of O(3) on spaces of complex spherical harmonics, modelling oscillations of a liquid drop.

Montaldi, J. A.; Roberts, R. M.; Stewart, I. N.

1988-05-01

125

Periodically driven ergodic and many-body localized quantum systems

We study dynamics of isolated quantum many-body systems whose Hamiltonian is switched between two different operators periodically in time. The eigenvalue problem of the associated Floquet operator maps onto an effective hopping problem. Using the effective model, we establish conditions on the spectral properties of the two Hamiltonians for the system to localize in energy space. We find that ergodic systems always delocalize in energy space and heat up to infinite temperature, for both local and global driving. In contrast, many-body localized systems with quenched disorder remain localized at finite energy. We support our conclusions by numerical simulations of disordered spin chains. We argue that our results hold for general driving protocols, and discuss their experimental implications.

Ponte, Pedro; Chandran, Anushya; Papi?, Z.; Abanin, Dmitry A.

2015-02-01

126

Determination of the Period of Binary Asteroid Systems

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

127

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

128

Dimension Reduction Near Periodic Orbits of Hybrid Systems

When the Poincar\\'{e} map associated with a periodic orbit of a hybrid dynamical system has constant-rank iterates, we demonstrate the existence of a constant-dimensional invariant subsystem near the orbit which attracts all nearby trajectories in finite time. This result shows that the long-term behavior of a hybrid model with a large number of degrees-of-freedom may be governed by a low-dimensional smooth dynamical system. The appearance of such simplified models enables the translation of analytical tools from smooth systems-such as Floquet theory-to the hybrid setting and provides a bridge between the efforts of biologists and engineers studying legged locomotion.

Burden, Samuel; Sastry, S Shankar

2011-01-01

129

International Nuclear Information System (INIS)

The part of free neutral atoms N0 of all elements being contained in protoplanet cloud is estimated with regard to their abundance and physicochemical properties. Linear dependence of ratio of volatile and nonvolatile elements in chondrites and in eruptive Earth rocks on N0 is obtained. Ratios of concentrations of element-analogs with different N0 in substances of Venus, Earth, Mars and chondrites are compared. Obtained data are an evidence that hypothetical process of magnetic separation in protoplanet cloud has been taken place

130

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

131

Discrete changes of current statistics in periodically driven stochastic systems

International Nuclear Information System (INIS)

We demonstrate that the counting statistics of currents in periodically driven ergodic stochastic systems can show sharp changes of some of its properties in response to continuous changes of the driving protocol. To describe this effect, we introduce a new topological phase factor in the evolution of the moment generating function which is akin to the topological geometric phase in the evolution of a periodically driven quantum mechanical system with time-reversal symmetry. This phase leads to the prediction of a sign change for the difference of the probabilities to find even and odd numbers of particles transferred in a stochastic system in response to cyclic evolution of control parameters. The driving protocols that lead to this sign change should enclose specific degeneracy points in the space of control parameters. The relation between the topology of the paths in the control parameter space and the sign changes can be described in terms of the first Stiefel–Whitney class of topological invariants. (letter)

132

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

133

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

134

Periodic permanent magnet focusing system with high peak field

In this study, hybrid periodic permanent magnet (PPM) system is studied, which has high axial magnetic field and low magnetic leakage. By simulation computation, some laws of magnetic field distribution vs. structure dimensions were obtained. A hybrid PPM is designed and constructed whose peak field reaches 0.6 T. The factors inducing discrepancies between computational results and practical measurements are analyzed. The magnetic field distribution is very sensitive to the variations of constructional parameters. Construction accuracy greatly influences the magnetic field distribution. Research results obtained here are potentially valuable for future work.

Hong, Zhang; Weiwei, Liu; Shuxin, Bai; Ke, Chen

135

Periodic permanent magnet focusing system with high peak field

International Nuclear Information System (INIS)

In this study, hybrid periodic permanent magnet (PPM) system is studied, which has high axial magnetic field and low magnetic leakage. By simulation computation, some laws of magnetic field distribution vs. structure dimensions were obtained. A hybrid PPM is designed and constructed whose peak field reaches 0.6 T. The factors inducing discrepancies between computational results and practical measurements are analyzed. The magnetic field distribution is very sensitive to the variations of constructional parameters. Construction accuracy greatly influences the magnetic field distribution. Research results obtained here are potentially valuable for future work

136

Semiclassical quantization of nonadiabatic systems with hopping periodic orbits

We present a semiclassical quantization condition, i.e., quantum-classical correspondence, for steady states of nonadiabatic systems consisting of fast and slow degrees of freedom (DOFs) by extending Gutzwiller's trace formula to a nonadiabatic form. The quantum-classical correspondence indicates that a set of primitive hopping periodic orbits, which are invariant under time evolution in the phase space of the slow DOF, should be quantized. The semiclassical quantization is then applied to a simple nonadiabatic model and accurately reproduces exact quantum energy levels. In addition to the semiclassical quantization condition, we also discuss chaotic dynamics involved in the classical limit of nonadiabatic dynamics.

Fujii, Mikiya; Yamashita, Koichi

2015-02-01

137

Robust detection of periodic time series measured from biological systems

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Periodic phenomena are widespread in biology. The problem of finding periodicity in biological time series can be viewed as a multiple hypothesis testing of the spectral content of a given time series. The exact noise characteristics are unknown in many bioinformatics applications. Furthermore, the observed time series can exhibit other non-idealities, such as outliers, short length and distortion from the original wave form. Hence, the computational methods should preferably be robust against such anomalies in the data. Results We propose a general-purpose robust testing procedure for finding periodic sequences in multiple time series data. The proposed method is based on a robust spectral estimator which is incorporated into the hypothesis testing framework using a so-called g-statistic together with correction for multiple testing. This results in a robust testing procedure which is insensitive to heavy contamination of outliers, missing-values, short time series, nonlinear distortions, and is completely insensitive to any monotone nonlinear distortions. The performance of the methods is evaluated by performing extensive simulations. In addition, we compare the proposed method with another recent statistical signal detection estimator that uses Fisher's test, based on the Gaussian noise assumption. The results demonstrate that the proposed robust method provides remarkably better robustness properties. Moreover, the performance of the proposed method is preferable also in the standard Gaussian case. We validate the performance of the proposed method on real data on which the method performs very favorably. Conclusion As the time series measured from biological systems are usually short and prone to contain different kinds of non-idealities, we are very optimistic about the multitude of possible applications for our proposed robust statistical periodicity detection method. Availability The presented methods have been implemented in Matlab and in R. Codes are available on request. Supplementary material is available at: http://www.cs.tut.fi/sgn/csb/robustperiodic/.

Huttunen Heikki

2005-05-01

138

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

139

Optimal stabilization of unstable periodic orbits embedded in chaotic systems

Scientific Electronic Library Online (English)

Full Text Available 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

140

Development of a Periodic Loading System using a Bellows

International Nuclear Information System (INIS)

An instrumented capsule is one of the devices to investigate the irradiation effects of the nuclear reactor materials and components being used in a research reactor, HANARO. Among various capsules, a special capsule for in-pile creep and fatigue tests has been under development since 2002. A bellows was used to apply the constant load to the specimen in the creep capsule, and various studies have been performed to determine the specification of the bellows. But the load's concept for the fatigue test is slightly different with the creep test. It is necessary to repeat a force with a constant period and amplitude during the life of the specimen. Thus, for the fatigue test using an instrumented capsule, it is important to realize the load's shape being applied to the specimen. In this study, the out-pile loading system using the bellows to apply the actual fatigue capsule is developed, and it is performed by modifying the previous system which was developed for the out-pile creep test. The basic structure, the control system and the main function related to the new loading system are described, and the preliminary test results and the future works are also discussed

141

Geometry optimization of periodic systems using internal coordinates.

An algorithm is proposed for the structural optimization of periodic systems in internal (chemical) coordinates. Internal coordinates may include in addition to the usual bond lengths, bond angles, out-of-plane and dihedral angles, various "lattice internal coordinates" such as cell edge lengths, cell angles, cell volume, etc. The coordinate transformations between Cartesian (or fractional) and internal coordinates are performed by a generalized Wilson B-matrix, which in contrast to the previous formulation by Kudin et al. [J. Chem. Phys. 114, 2919 (2001)] includes the explicit dependence of the lattice parameters on the positions of all unit cell atoms. The performance of the method, including constrained optimizations, is demonstrated on several examples, such as layered and microporous materials (gibbsite and chabazite) as well as the urea molecular crystal. The calculations used energies and forces from the ab initio density functional theory plane wave method in the projector-augmented wave formalism. PMID:15836398

Bucko, Tomás; Hafner, Jürgen; Angyán, János G

2005-03-22

142

A period-by-period ion milling system has been developed for final reflection wavefront error correction of an imaging EUV multilayer mirror by a stepwise 0.1 nm-per-period correction of the residual nm figure errors. For effective, gentle and uniform milling of the surface areas selected by a template, the system is designed with a rotating substrate holder exposed to a 150 mm-wide ion beam with a dose homogenizer mask plate. For demonstration of the wavefront correction principle, local milling of a dielectric multilayer mirror for visible light was carried out by the system. The wavefront as measured by a phase shifting interferometer showed that the reflection phase was "advanced" by the milling, which formed a geometrical depression at the multilayer mirror surface. This confirmed the physical optics principle of our method and proved the procedure of the method being promising and practical for the accurate reflection phase correction of an EUV multilayer mirror.

Tsuru, T.; Tosaka, A.; Sakai, Y.; Yamamoto, M.

2009-09-01

143

In this paper, the performance of a direct sequence spread-spectrum system is analyzed with both a long period sequence and with a sequence whose period is one bit long. Bit error rates for both quadriphase and biphase chip spreading, in conjunction with both QPSK and BPSK data, are considered in the presence of noise and jamming. The frequency location of the jammer is arbitrary.

Lunayach, R. S.

1983-03-01

144

...2010-04-01 false Will SSA periodically review the outcome payment system and the outcome-milestone payment system for possible modifications...411.597 Will SSA periodically review the outcome payment system and the outcome-milestone...

2010-04-01

145

A Long-Period Grating Sensor System Monitoring Loads on a Wind Turbine Blade

DEFF Research Database (Denmark)

We demonstrate the utilization of a blade load sensor system based on two identical Long-Period Gratings in a Mach-Zehnder configuration. The experimental results demonstrate the potential of a Long-Period Grating based load interrogation system.

Glavind, Lars; Buggy, Stephen

2014-01-01

146

Gap solitons and Bloch waves in nonlinear periodic systems

International Nuclear Information System (INIS)

We comprehensively investigate gap solitons and Bloch waves in one-dimensional nonlinear periodic systems. Our results show that there exists a composition relation between them: Bloch waves at either the center or edge of the Brillouin zone are infinite chains composed of fundamental gap solitons (FGSs). We argue that such a relation is related to the exact relation between nonlinear Bloch waves and nonlinear Wannier functions. With this composition relation, many conclusions can be drawn for gap solitons without any computation. For example, for the defocusing nonlinearity, there are n families of FGS in the nth linear Bloch band gap; for the focusing case, there are infinite number of families of FGSs in the semi-infinite gap and other gaps. In addition, the stability of gap solitons is analyzed. In literature, there are numerical results showing that some FGSs have cutoffs on propagation constant (or chemical potential), i.e., these FGSs do not exist for all values of propagation constant (or chemical potential) in the linear band gap. We develop an intuitive picture to describe this cutoff.

147

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

148

Directory of Open Access Journals (Sweden)

Full Text Available We prove that a family of $q$-periodic continuous matrix valued function ${A(t}_{tin mathbb{R}}$ has an exponential dichotomy with a projector $P$ if and only if $int_0^t e^{imu s}U(t,sPds$ is bounded uniformly with respect to the parameter $mu$ and the solution of the Cauchy operator Problem $$displaylines{ dot{Y}(t=-Y(tA(t+ e^{i mu t}(I-P ,quad tgeq s cr Y(s=0, }$$ has a limit in $mathcal{L}(mathbb{C}^n$ as s tends to $-infty$ which is bounded uniformly with respect to the parameter $mu$. Here, ${ U(t,s: t, sinmathbb{R}}$ is the evolution family generated by ${A(t}_{tin mathbb{R}}$, $mu$ is a real number and q is a fixed positive number.

Dhaou Lassoued

2013-04-01

149

Extended Aharonov-Bohm period analysis of strongly correlated electron systems

The `extended Aharonov-Bohm (AB) period' recently proposed by Kusakabe and Aoki [J. Phys. Soc. Jpn (65), 2772 (1996)] is extensively studied numerically for finite size systems of strongly correlated electrons. While the extended AB period is the system length times the flux quantum for noninteracting systems, we have found the existence of the boundary across which the period is halved or another boundary into an even shorter period on the phase diagram for these models. If...

Arita, Ryotaro; Kusakabe, Koichi; Kuroki, Kazuhiko; Aoki, Hideo

1996-01-01

150

In this paper, we introduce concepts of pathwise random almost periodic and almost automorphic solutions for dynamical systems generated by non-autonomous stochastic equations. These solutions are pathwise stochastic analogues of deterministic dynamical systems. The existence and bifurcation of random periodic (random almost periodic, random almost automorphic) solutions have been established for a one-dimensional stochastic equation with multiplicative noise.

Wang, Bixiang

2014-01-01

151

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

...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

152

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

153

Gravitational Waves from Periodic Three-Body Systems

Three bodies moving in a periodic orbit under the influence of Newtonian gravity ought to emit gravitational waves. We have calculated the gravitational radiation quadrupolar waveforms and the corresponding luminosities for the 13+11 recently discovered three-body periodic orbits in Newtonian gravity. These waves clearly allow one to distinguish between their sources: all 13+11 orbits have different waveforms and their luminosities (evaluated at the same orbit energy and body mass) vary by up to 13 orders of magnitude in the mean, and up to 20 orders of magnitude for the peak values.

Dmitrašinovi?, V; Hudomal, Ana

2015-01-01

154

Gravitational waves from periodic three-body systems.

Three bodies moving in a periodic orbit under the influence of Newtonian gravity ought to emit gravitational waves. We have calculated the gravitational radiation quadrupolar waveforms and the corresponding luminosities for the 13+11 recently discovered three-body periodic orbits in Newtonian gravity. These waves clearly allow one to distinguish between their sources: all 13+11 orbits have different waveforms and their luminosities (evaluated at the same orbit energy and body mass) vary by up to 13 orders of magnitude in the mean, and up to 20 orders of magnitude for the peak values. PMID:25238346

Dmitrašinovi?, V; Suvakov, Milovan; Hudomal, Ana

2014-09-01

155

As part of an international agreement between the UK and the USSR (Cooperation in Metrology), the respective national standards of voltage based on Josephson-effect systems situated at the Mendeleev Institute of Metrology (VNIIM), Leningrad and the National Physical Laboratory (NPL), Teddington have been intercompared using two separate groups of transportable standard cells in the period December 1981 to December 1982. For a group of cells maintained at 30 °C in a commercial thermoregulated enclosure it was found that (VVNIIM - VNPL)/VNPL = + 4.63 × 10-6; and for a group of bare cells measured at 20 °C (VVNIIM - VNPL)/VNPL = + 5.18 × 10-6, with + 4.50 × 10-6 of this difference being due to the different values of the Josephson constants (nominally 2e/h) used in the two countries.

Hartland, A.; Harkness, S.; Krause, P. J.; Galakhova, O. P.; Krzhimovskii, V. I.; Korotkova, I. V.

1985-01-01

156

Signatures of resonant terrestrial planets in long-period systems

The majority of extrasolar planets discovered to date have significantly eccentric orbits, some if not all of which may have been produced through planetary migration. During this process, any planets interior to such an orbit would therefore have been susceptible to resonance capture, and hence may exhibit measurable orbital period variations. Here we summarize the results of our investigation into the possibility of detecting low-mass planets which have been captured into ...

Kennedy, Gareth F.; Mardling, Rosemary A.

2009-01-01

157

High Frequency Stochastic Resonance in Periodically Driven Systems

High frequency stochastic resonance (SR) phenomena, associated with fluctuational transitions between coexisting periodic attractors, have been investigated experimentally in an electronic model of a single-well Duffing oscillator bistable in a nearly resonant field of frequency $\\omega_F$. It is shown that, with increasing noise intensity, the signal/noise ratio (SNR) for a signal due to a weak trial force of frequency $\\Omega \\sim \\omega_F$ at first decreases, then {\\it in...

Dykman, M. I.; Luchinsky, D. G.; Mannella, R.; Mcclintock, P. V. E.; Soskin, S. M.; Stein, N. D.; Stocks, N. G.

1993-01-01

158

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

159

Finite-temperature crossovers in periodic disordered systems

We consider the static properties of periodic structures in weak random disorder. We apply a functional renormalization group approach (FRG) and a Gaussian variational method (GVM) to study their displacement correlations. We focus in particular on the effects of temperature and we compute explicitly the crossover length scales separating different regimes in the displacement correlation function. We compare the FRG and GVM results and find excellent agreement. We show that the FRG predicts, in addition, the existence of a third length scale associated with the screening of the disorder by thermal fluctuations and discuss a protocol to observe it.

Foini, L.; Giamarchi, T.

2015-03-01

160

A principle of valence and relativistic effects in the light of Mendeleev law

International Nuclear Information System (INIS)

The influence of relativistic effects on the properties of heavy elements is shown. Using as an example transition d-elements, the role of relativistic effects in the stability of electron configuration of the ground state is studied, a comparison of chemical properties in series and periods is carried out. Special attention is paid to lanthanides and actinides. Importance of relativistic effects in the stability of valence forms, in changes of oxidation potentials, in existence of new oxidation rates is pointed out

161

Bifurcations from one-parameter families of symmetric periodic orbits in reversible systems

International Nuclear Information System (INIS)

We study bifurcations from one-parameter families of symmetric periodic orbits in reversible systems and give simple criteria for subharmonic symmetric periodic orbits to be born from the one-parameter families. Our result is illustrated for a generalization of the Hénon–Heiles system. In particular, it is shown that there exist infinitely many families of symmetric periodic orbits bifurcating from a family of symmetric periodic orbits under a general condition. Numerical computations for these bifurcations and symmetric periodic orbits are also given. (paper)

162

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.

163

Regulatory strategy for effective application of periodic safety review system

International Nuclear Information System (INIS)

In less than 10 years, the first commercial pressurized water reactor (PWR) plant in Korea will reach its official design life. As part of safety activities, developed countries have already implemented periodic safety review (PSR) or equivalent programs to check and improve the safety of operating nuclear power plants (NPP) during their plant life. At the end of 1999, it was decided by the Korean Atomic Energy Safety Committee to adopt the PSR program and to apply it to Korean operating NPP. Since Kori Unit 1 started the review for the first tentative application of PSR as a model case in May 2000, it is now progressing well. Management of aging is one of the major factors to be considered in PSR and life extension of a nuclear plant. This paper is intended to introduce the regulatory aspect and strategy of Korean PSR. The background and scope of basic PSR guidelines are described, and a summary of technical criteria for aging management, which shows a regulatory direction for PSR, is also presented

164

Evaluation of electric power distribution systems: period 1984/89

International Nuclear Information System (INIS)

The historical evolution of electric power distribution systems in Brazil, during 1984 to 1989 is described, showing the consumer market with the physical expansion of Distribution Networks and the results of quality from the services made by the companies to their clients. (C.G.C.)

165

Selfdual Variational Principles for Periodic Solutions of Hamiltonian and Other Dynamical Systems

Selfdual variational principles are introduced in order to construct solutions for Hamiltonian and other dynamical systems which satisfy a variety of linear and nonlinear boundary conditions including many of the standard ones. These principles lead to new variational proofs of the existence of parabolic flows with prescribed initial conditions, as well as periodic, anti-periodic and skew-periodic orbits of Hamiltonian systems. They are based on the theory of anti-selfdual L...

Ghoussoub, Nassif; Moameni, Abbas

2005-01-01

166

A study of the entanglement in systems with periodic boundary conditions

We define the local periodic linking number, LK, between two oriented closed or open chains in a system with three-dimensional periodic boundary conditions. The properties of LK indicate that it is an appropriate measure of entanglement between a collection of chains in a periodic system. Using this measure of linking to assess the extent of entanglement in a polymer melt we study the effect of CReTA algorithm on the entanglement of polyethylene chains. Our numerical results...

Panagiotou, E.; Tzoumanekas, C.; Lambropoulou, S.; Millett, K. C.; Theodorou, D. N.

2010-01-01

167

On angular momentum balance for particle systems with periodic boundary conditions

The well-known issue with the absence of conservation of angular momentum in classical particle systems with periodic boundary conditions is addressed. It is shown that conventional theory based on Noether's theorem fails to explain the simplest possible example, notably jumps of angular momentum in the case of single particle moving in a periodic cell. It is suggested to consider the periodic cell as an open system, exchanging mass, momentum, angular momentum, and energy wi...

Kuzkin, Vitaly A.

2013-01-01

168

...Commission [Docket No. EL13-21-000] California Independent System Operator Corporation; Notice Establishing Answer...regarding the comment period for the California Independent System Operator Corporation's (CAISO) petition...

2012-11-26

169

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.

Hristova, S. G.; Vatsala, A. S.

2006-01-01

170

Controlling chaos in a high dimensional system with periodic parametric perturbations

Energy Technology Data Exchange (ETDEWEB)

The effect of applying a periodic perturbation to an accessible parameter of a high-dimensional (coupled-Lorenz) chaotic system is examined. Numerical results indicate that perturbation frequencies near the natural frequencies of the unstable periodic orbits of the chaotic system can result in limit cycles or significantly reduced dimension for relatively small perturbations.

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

1998-10-01

171

Virial theorem and exact properties of density functionals for periodic systems

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

172

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

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

2014-01-01

173

Controlling chaos in a high dimensional system with periodic parametric perturbations

International Nuclear Information System (INIS)

The effect of applying a periodic perturbation to an accessible parameter of a high-dimensional (coupled-Lorenz) chaotic system is examined. Numerical results indicate that perturbation frequencies near the natural frequencies of the unstable periodic orbits of the chaotic system can result in limit cycles or significantly reduced dimension for relatively small perturbations

174

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.

175

Design of real-time periodic control systems through synchronization and fixed priorities

Control systems are often designed using a set of co-operating periodic modules running under control of a real-time operating system. A correct behaviour of the closed-loop controller requires that the system meets timing constraints like periods and latencies, which can be expressed as deadlines. The control system timing requirements are captured through a partition in control paths by which priorities are assigned according to their relative urgency. Latencies are managed through preceden...

Simon, Daniel; Benattar, Fanny

2005-01-01

176

Design of real-time periodic control systems through synchronisation and fixed priorities

Control systems are often designed using a set of cooperating periodic modules running under control of a real-time operating system. A correct behaviour of the closed-loop controller requires that the system meets timing constraints like periods and latencies, which can be expressed as deadlines. The software uses the fixed priority based preemption service of the operating system. Latencies are controlled through precedence constraints and more or less tight synchronisation between modules....

Simon, Daniel; Benattar, Fanny

2002-01-01

177

The orbital periods of three sdB eclipsing binary systems

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

178

Dynamics of a periodic Watt-type predator-prey system with impulsive effect

Energy Technology Data Exchange (ETDEWEB)

In this paper, an impulsive periodic predator-prey system with Watt-type functional response is investigated. By using the Floquet theory of linear periodic impulsive equation, the stability conditions for the prey-eradication positive periodic solution are given, and the boundedness of the system is proved. By the method of coincidence degree, the sufficient conditions for the existence of at least one strictly positive periodic solution are obtained. Furthermore, we give numerical analysis to confirm our theoretical results. It will be useful for ecosystem control.

Wang Xiaoqin [Faculty of Science, Shaanxi University of Science and Technology, Xianyang, Shaanxi 712081 (China)], E-mail: wangxiaoqin@sust.edu.cn; Wang Weiming [School of Mathematics and Information Science, Wenzhou University, Wenzhou, Zhejiang 325035 (China)], E-mail: weimingwang2003@163.com; Lin Xiaolin [Faculty of Science, Shaanxi University of Science and Technology, Xianyang, Shaanxi 712081 (China)

2009-02-15

179

Damped periodically driven quantum transport in bistable systems

International Nuclear Information System (INIS)

The quantum dynamics of quartic double well, subjected to a harmonically oscillating field, is studied in the framework of the Floquet formalism. The modifications of the familiar tunneling process due to driving and dissipation are investigated numerically and explained in terms of the quasi-energy spectrum. In absence of dissipation, there is a one-dimensional manifold in the parameter space spanned by amplitude and frequency of the driving force, where tunneling is almost completely suppressed by the coherent driving. The influence of dissipation is described on basis of the reduced density matrix in the Floquet representation. In particular, we consider the effect of weak Ohmic damping. In the classical limit, this system corresponds to a damped bistable Duffing oscillator. The interplay of coherent and incoherent transport processes is studied in terms of the transient time evolution of a temporal autocorrelation function. We find that the coherent suppression of tunneling is stabilized by reservoir-induced noise for a suitably chosen temperature. By computing stroboscopic Husimi distributions, we also compare the quantal stationary states with the corresponding classical deterministic attractors. (author). 34 refs, 5 figs

180

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...

Corte?s, C.; Catelan, M.

2008-01-01

181

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

182

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

183

Chaotic Dynamics of One-Dimensional Systems with Periodic Boundary Conditions

We provide appropriate tools for the analysis of dynamics and chaos for one-dimensional systems with periodic boundary conditions. Our approach allows for the investigation of the dependence of the largest Lyapunov exponent on various initial conditions of the system. The method employs an effective approach for defining the phase-space distance appropriate for systems with periodic boundary and allows for an unambiguous test-orbit rescaling in the phase space required to ca...

Kumar, Pankaj; Miller, Bruce N.

2014-01-01

184

Periodic solutions for nonlinear integro-differential systems with piecewise constant argument.

We investigate the existence of the periodic solutions of a nonlinear integro-differential system with piecewise alternately advanced and retarded argument of generalized type, in short DEPCAG; that is, the argument is a general step function. We consider the critical case, when associated linear homogeneous system admits nontrivial periodic solutions. Criteria of existence of periodic solutions of such equations are obtained. In the process we use Green's function for periodic solutions and convert the given DEPCAG into an equivalent integral equation. Then we construct appropriate mappings and employ Krasnoselskii's fixed point theorem to show the existence of a periodic solution of this type of nonlinear differential equations. We also use the contraction mapping principle to show the existence of a unique periodic solution. Appropriate examples are given to show the feasibility of our results. PMID:24574895

Chiu, Kuo-Shou

2014-01-01

185

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

186

Periodic Solutions of the 1D Vlasov-Maxwell System with Boundary Conditions

We study the 1D Vlasov-Maxwell system with time periodic boundary conditions in its classical and relativistic form. For small data we prove existence of weak periodic solutions. It is necessary to impose non vanishing conditions for the incoming velocities in order to control the life-time of particles in the domain. In order to preserve the periodicity, another condition of vanishing the time average of the incoming current is imposed.

Bostan, Mihai

1998-01-01

187

Mean Switching Frequency Locking in Stochastic Bistable Systems Driven by a Periodic Force

The nonlinear response of noisy bistable systems driven by a strong amplitude-periodic force is investigated by physical experiment. The new phenomenon of locking of the mean switching frequency between states of a bistable system is found. It is shown that there is an interval of noise intensities in which the mean switching frequency remains constant and coincides with the frequency of the external periodic force. The region on the parameter plane ``noise intensity-amplitude of periodic excitation'' which corresponds to this phenomenon is similar to the synchronization (phase locking) region (Arnold's tongue) in classical oscillatory systems.

Shulgin, Boris; Neiman, Alexander; Anishchenko, Vadim

1995-12-01

188

Stochastic long term modelling of a drainage system with estimation of return period uncertainty

DEFF Research Database (Denmark)

Long term prediction of maximum water levels and combined sewer overflow (CSO) in drainage systems are associated with large uncertainties. Especially on rainfall inputs, parameters, and assessment of return periods. This paper proposes a Monte Carlo based methodology for stochastic prediction of both maximum water levels as well as CSO volumes based on operations of the urban drainage model MOUSE (Lindberg and Joergensen 1986) in a single catchment case study. Results show quite a wide confidence interval of the model predictions especially on the large return periods. Traditionally, return periods of drainage system predictions are based on ranking, but this paper proposes a new methodology for the assessment of return periods. Based on statistics of characteristic rainfall parameters and correlation with drainage system predictions, it is possible to predict return periods more reliably, and with smaller confidence bands compared to the traditional methodology.

Thorndahl, SØren

2009-01-01

189

Stochastic Long Term Modelling of a Drainage System with Estimation of Return Period Uncertainty

DEFF Research Database (Denmark)

Long term prediction of maximum water levels and combined sewer overflow (CSO) in drainage systems are associated with large uncertainties. Especially on rainfall inputs, parameters, and assessment of return periods. This paper proposes a Monte Carlo based methodology for stochastic prediction of both maximum water levels as well as CSO volumes based on operations of the urban drainage model MOUSE (Lindberg and Joergensen 1986) in a single catchment case study. Results show quite a wide confidence interval of the model predictions especially on the large return periods. Traditionally, return periods of drainage system predictions are based on ranking, but this paper proposes a new methodology for the assessment of return periods. Based on statistics of characteristic rainfall parameters and correlation with drainage system predictions, it is possible to predict return periods more reliably, and with smaller confidence bands compared to the traditional methodology.

Thorndahl, SØren

2008-01-01

190

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

Energy Technology Data Exchange (ETDEWEB)

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.

Souza, S.L.T. de, E-mail: thomaz@ufsj.edu.br [Departamento de Física e Matemática, Universidade Federal de São João del-Rei, Ouro Branco, MG (Brazil); Lima, A.A. [Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, MG (Brazil); Caldas, I.L. [Instituto de Física, Universidade de São Paulo, São Paulo, SP (Brazil); Medrano-T, R.O. [Departamento de Ciências Exatas e da Terra, Universidade Federal de São Paulo, Diadema, SP (Brazil); Guimarães-Filho, Z.O. [Aix-Marseille Univ., CNRS PIIM UMR6633, International Institute for Fusion Science, Marseille (France)

2012-03-12

191

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.

192

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.

193

Stochastic period-doubling bifurcation in biharmonic driven Duffing system with random parameter

International Nuclear Information System (INIS)

Stochastic period-doubling bifurcation is explored in a forced Duffing system with a bounded random parameter as an additional weak harmonic perturbation added to the system. Firstly, the biharmonic driven Duffing system with a random parameter is reduced to its equivalent deterministic one, and then the responses of the stochastic system can be obtained by available effective numerical methods. Finally, numerical simulations show that the phase of the additional weak harmonic perturbation has great influence on the stochastic period-doubling bifurcation in the biharmonic driven Duffing system. It is emphasized that, different from the deterministic biharmonic driven Duffing system, the intensity of random parameter in the Duffing system can also be taken as a bifurcation parameter, which can lead to the stochastic period-doubling bifurcations

194

Maximal regularity of the time-periodic Navier-Stokes system

Time-periodic solutions to the linearized Navier-Stokes system in the $n$-dimensional whole-space are investigated. For time-periodic data in $L^q$-spaces, maximal regularity and corresponding a priori estimates for the associated time-periodic solutions are established. More specifically, a Banach space of time-periodic vector fields is identified with the property that the linearized Navier-Stokes operator maps this space homeomorphically onto the $L^q$-space of time-perio...

Kyed, Mads

2013-01-01

195

Impurity composition of specimens of special-purity substances at the collection exhibition

International Nuclear Information System (INIS)

The Certificates of the purest specimens of simple solid substanes of 6-th period of D.I. Mendeleev system are given. The degree of purity of simple substances of various periods of the system is compared

196

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

197

Stochastic Resonance in Time-delayed Bistable Systems Driven by Weak Periodic Signal

We study theoretically a bistable systems with time-delayed feedback driven by weak periodic force. The effective potential function and the steady-state probability density are derived. The delay time and the strength of its feedback can change the shapes of the potential wells. In the adiabatic approximation, the signal-to-noise ratio (SNR) of the system with a weak periodic force is obtained. The time-delayed feedback modulates the magnitude of SNR by changing the shape o...

Shao, Rui-hua; Chen, Yong

2008-01-01

198

Current and fluctuation in a two-state stochastic system under non-adiabatic periodic perturbation

We calculate a current and its fluctuation in a two-state stochastic system under a periodic perturbation. The system could be interpreted as a channel on a cell surface or a single Michaelis-Menten catalyzing enzyme. It has been shown that the periodic perturbation induces so-called pump current, and the pump current and its fluctuation are calculated with the aid of the geometrical phase interpretation. We give a simple calculation recipe for the statistics of the current,...

Ohkubo, Jun

2007-01-01

199

Many-body position operator in lattice fermionic systems with periodic boundary conditions

A total position operator $X$ in the position representation is derived for lattice fermionic systems with periodic boundary conditions. The operator is shown to be Hermitian, the generator of translations in momentum space, and its time derivative is shown to correspond to the total current operator in a periodic system. The operator is such that its moments can be calculated up to any order. To demonstrate its utility finite size scaling is applied to the Brinkman-Rice tra...

Hetenyi, Balazs

2009-01-01

200

The Period-Ratio and Mass-Ratio Correlation in Extra-Solar Multiple Planetary Systems

Employing the data from orbital periods and masses of extra-solar planets in 166 multiple planetary systems, the period-ratio and mass-ratio of adjacent planet pairs are studied. The correlation between the period-ratio and mass-ratio is confirmed and found to have a correlation coefficient of 0.5303 with a 99% confidence interval (0.3807, 0.6528). A comparison with the distribution of synthetic samples from a Monte Carlo simulation reveals the imprint of planet-planet interactions on the formation of adjacent planet pairs in multiple planetary systems.

Jiang, Ing-Guey; Hung, Wen-Liang

2015-01-01

201

Selfdual Variational Principles for Periodic Solutions of Hamiltonian and Other Dynamical Systems

Selfdual variational principles are introduced in order to construct solutions for Hamiltonian and other dynamical systems which satisfy a variety of linear and nonlinear boundary conditions including many of the standard ones. These principles lead to new variational proofs of the existence of parabolic flows with prescribed initial conditions, as well as periodic, anti-periodic and skew-periodic orbits of Hamiltonian systems. They are based on the theory of anti-selfdual Lagrangians introduced and developed recently in [3], [4] and [5].

Ghoussoub, N; Ghoussoub, Nassif; Abbas Moameni

2005-01-01

202

Composition Relation between Gap Solitons and Bloch Waves in Nonlinear Periodic Systems

International Nuclear Information System (INIS)

We show with numerical computation and analysis that Bloch waves, at either the center or edge of the Brillouin zone, of a one dimensional nonlinear periodic system can be regarded as infinite chains composed of fundamental gap solitons (FGSs). This composition relation between Bloch waves and FGSs leads us to predict that there are n families of FGSs in the nth band gap of the corresponding linear periodic system, which is confirmed numerically. Furthermore, this composition relation can be extended to construct a class of solutions similar to Bloch waves but with multiple periods

203

Ultra-Short-Period Binary Systems in the OGLE Fields Toward the Galactic Bulge

We present a sample of 242 ultra-short-period (P < 0.22 d) eclipsing and ellipsoidal binary stars identified in the OGLE fields toward the Galactic bulge. Based on the light curve morphology, we divide the sample into candidates for contact binaries and non-contact binaries. In the latter group we distinguish binary systems consisting of a cool main-sequence star and a B-type subdwarf (HW Vir stars) and candidates for cataclysmic variables, including five eclipsing dwarf novae. One of the detected eclipsing binary systems - OGLE-BLG-ECL-000066 - with the orbital period below 0.1 d, likely consists of M dwarfs in a nearly contact configuration. If confirmed, this would be the shortest-period M-dwarf binary system currently known. We discuss possible evolutionary mechanisms that could lead to the orbital period below 0.1 d in an M-dwarf binary.

Soszynski, I; Pilecki, B; Mroz, P; Udalski, A; Szymanski, M K; Pietrzynski, G; Wyrzykowski, L; Ulaczyk, K; Poleski, R; Kozlowski, S; Pietrukowicz, P; Skowron, J; Pawlak, M

2015-01-01

204

Periodic orbits and their stability in the Rössler prototype-4 system

International Nuclear Information System (INIS)

For the Rössler prototype-4 system x.=?y?z, y.=x, z.=?y(1?y)??z we prove the existence of periodic orbits and study their stability or instability. The main tool for proving these results is the averaging theory. Recently the existence of some of these periodic orbits were detected numerically. -- Highlights: ? We deal with the Rössler prototype-4 system x.=?y?z, y.=x, z.=?y(1?y)??z. ? It is one of the simplest autonomous differential equations exhibiting chaos. ? Recently some periodic orbits for this system has been detected numerically. ? We provide an analytical proof of these orbits and study their stability. ? Also we prove the existence of periodic orbits not detected numerically.

205

Periodic orbits and their stability in the Rössler prototype-4 system

Energy Technology Data Exchange (ETDEWEB)

For the Rössler prototype-4 system x{sup .}=?y?z, y{sup .}=x, z{sup .}=?y(1?y)??z we prove the existence of periodic orbits and study their stability or instability. The main tool for proving these results is the averaging theory. Recently the existence of some of these periodic orbits were detected numerically. -- Highlights: ? We deal with the Rössler prototype-4 system x{sup .}=?y?z, y{sup .}=x, z{sup .}=?y(1?y)??z. ? It is one of the simplest autonomous differential equations exhibiting chaos. ? Recently some periodic orbits for this system has been detected numerically. ? We provide an analytical proof of these orbits and study their stability. ? Also we prove the existence of periodic orbits not detected numerically.

García, Isaac A., E-mail: garcia@matematica.udl.cat [Departament de Matemàtica, Universitat de Lleida, Avda. Jaume II, 69, 25001 Lleida, Catalonia (Spain); Llibre, Jaume, E-mail: jllibre@mat.uab.cat [Departament de Matemàtiques, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Catalonia (Spain); Maza, Susanna, E-mail: smaza@matematica.udl.cat [Departament de Matemàtica, Universitat de Lleida, Avda. Jaume II, 69, 25001 Lleida, Catalonia (Spain)

2012-07-02

206

Phase velocity and phase diffusion in periodically driven discrete-state systems.

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 Pe clet number are analytically calculated. The latter indicates as a measure of phase-coherence forced synchronization of the stochastic system with respect to the periodic driving and exhibits a "bona fide" resonance. In a second step, the theory is applied to a non-Markovian two-state system modeling excitable systems. The results prove again stochastic synchronization to the periodic driving and are in good agreement with simulations of a stochastic FitzHugh-Nagumo system. PMID:15903411

Prager, T; Schimansky-Geier, L

2005-03-01

207

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

208

A general approach to the localization of unstable periodic orbits in chaotic dynamical systems

We present a method to detect the unstable periodic orbits of a multidimensional chaotic dynamical system. Our approach allows us to locate in an efficient way the unstable cycles of, in principle, arbitrary length with a high accuracy. Based on a universal set of linear transformations the originally unstable periodic orbits are transformed into stable ones and can consequently be detected and analyzed easily. This method is applicable to dynamical systems of any dimension and requires no preknowledges with respect to the solutions of the original chaotic system. As an example of application of our method we investigate the Ikeda attractor in some detail.

Schmelcher, P

1997-01-01

209

Local electric dipole moments for periodic systems via density functional theory embedding

We describe a novel approach for the calculation of local electric dipole moments for periodic systems. Since the position operator is ill-defined in periodic systems, maximally localized Wannier functions based on the Berry-phase approach are usually employed for the evaluation of local contributions to the total electric dipole moment of the system. We propose an alternative approach: within a subsystem-density functional theory based embedding scheme, subset electric dipole moments are derived without any additional localization procedure, both for hybrid and non-hybrid exchange-correlation functionals. This opens the way to a computationally efficient evaluation of local electric dipole moments in (molecular) periodic systems as well as their rigorous splitting into atomic electric dipole moments. As examples, Infrared spectra of liquid ethylene carbonate and dimethyl carbonate are presented, which are commonly employed as solvents in Lithium ion batteries.

Luber, Sandra

2014-12-01

210

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

211

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

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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

212

Existence of positive periodic solution of mutualism system with several delays

International Nuclear Information System (INIS)

In this paper, by using Mawhin coincidence degree, some sufficient conditions are obtained for the global existence of positive periodic solutions of a mutualism systems with bounded and unbounded delays. Our results generalize significantly improve those of Gopalsamy and He [Gopalsamy K, He XZ. Persistence, attractivity, and delay in facultative mutualism. J Math Anal Appl 1997;215:154-73], Yang et al. [Yang F, Jiang D, Ying A. Existence of positive solution of multidelays facultative mutualism system. J Eng Math 2002;3:64-8], Chen et al. [Chen FD, Shi JL, Chen XX. Periodicity in Lotka-Volterra facultative mutualism system with several delays. J Eng Math 2004;21(3)] and Xia and Lin [Xia YH, Lin M, Existence of positive periodic solution of mutualism system with infinite delays. Ann Diff Eqs 2005;21(3):448-53

213

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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.

2006-01-01

214

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

215

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

216

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

217

International Nuclear Information System (INIS)

In the paper fundamental considerations concerning vibration studies in nonlinear systems are presented. Moreover, the realization of an experimental setup as well as measurements on a simple nonlinear vibrational system are treated. The excitation is performed by applying periodical impacts to a linear vibrator appropriately modified. (orig.)

218

SEARCHES FOR PERIODIC NEUTRINO EMISSION FROM BINARY SYSTEMS WITH 22 AND 40 STRINGS OF ICECUBE

International Nuclear Information System (INIS)

In this paper, we present the results of searches for periodic neutrino emission from a catalog of binary systems. Such modulation, observed in the photon flux, would be caused by the geometry of these systems. In the analysis, the period is fixed by these photon observations, while the phase and duration of the neutrino emission are treated as free parameters to be fit with the data. If the emission occurs during ?20% or less of the total period, this analysis achieves better sensitivity than a time-integrated analysis. We use the IceCube data taken from 2007 May 31 to 2008 April 5 with its 22 string configuration and from 2008 April 5 to 2009 May 20 with its 40 string configuration. No evidence for neutrino emission is found, with the strongest excess occurring for Cygnus X-3 at 2.1? significance after accounting for trials. Neutrino flux upper limits for both periodic and time-integrated emission are provided.

219

Long-time Behavior of Isolated Periodically Driven Interacting Lattice Systems

We study the dynamics of isolated interacting spin chains that are periodically driven by sudden quenches. Using full exact diagonalization of finite chains, we show that these systems exhibit three distinct regimes. For short driving periods, the Floquet Hamiltonian is well approximated by the time-averaged Hamiltonian, while for long periods, the evolution operator exhibits properties of random matrices of a circular ensemble (CE). In between, there is a crossover regime. Based on a finite-size scaling analysis and analytic arguments, we argue that, for thermodynamically large systems and nonvanishing driving periods, the evolution operator always exhibits properties of the CE of random matrices. Consequently, the Floquet Hamiltonian is a nonlocal Hamiltonian with multispin interaction terms, and the driving leads to the equivalent of an infinite temperature state at long times. These results are connected to the breakdown of the Magnus expansion and are expected to hold beyond the specific lattice model considered.

D'Alessio, Luca; Rigol, Marcos

2014-10-01

220

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

221

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Full Text Available Global behaviors and optimal harvesting of a class of impulsive periodic logistic single-species system with continuous periodic control strategy is investigated. Four new sufficient conditions that guarantee the exponential stability of the impulsive evolution operator introduced by us are given. By virtue of exponential stability of the impulsive evolution operator, we present the existence, uniqueness and global asymptotical stability of periodic solutions. Further, the existence result of periodic optimal controls for a Bolza problem is given. At last, an academic example is given for demonstration.

2009-03-01

222

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Full Text Available Global behaviors and optimal harvesting of a class of impulsive periodic logistic single-species system with continuous periodic control strategy is investigated. Four new sufficient conditions that guarantee the exponential stability of the impulsive evolution operator introduced by us are given. By virtue of exponential stability of the impulsive evolution operator, we present the existence, uniqueness and global asymptotical stability of periodic solutions. Further, the existence result of periodic optimal controls for a Bolza problem is given. At last, an academic example is given for demonstration.

Xiang X

2008-01-01

223

Energy Technology Data Exchange (ETDEWEB)

We study the existence of spatial periodic solutions for nonlinear elliptic equations: -{delta}u + g(x,u(x)) = 0, x belongs to R{sup N} where g is a continuous function, non-decreasing w.r.t. u. We give necessary and sufficient conditions for the existence of periodic solutions. Some cases with non-increasing functions g are investigated as well. As an application we analyze the mathematical model of electron beam focusing system and we prove the existence of positive periodic solutions for the envelope equation. We present also numerical simulations. (authors)

Bostan, M. [Universite de Franche-Comte, Lab. de Mathematiques de Besancon, UMR CNRS 6623, 25 - Besancon (France); Sonnendrucker, E. [Universite Louis Pasteur, IRMA, 67 - Strasbourg (France)

2006-11-15

224

International Nuclear Information System (INIS)

We study the existence of spatial periodic solutions for nonlinear elliptic equations: -?u + g(x,u(x)) = 0, x belongs to RN where g is a continuous function, non-decreasing w.r.t. u. We give necessary and sufficient conditions for the existence of periodic solutions. Some cases with non-increasing functions g are investigated as well. As an application we analyze the mathematical model of electron beam focusing system and we prove the existence of positive periodic solutions for the envelope equation. We present also numerical simulations. (authors)

225

Bifurcation diagrams of periodic orbits for unbound molecular systems: FH 2

We present bifurcation diagrams of periodic orbits for the collinear FH 2 reactive system. The principal families which originate from the van der Waals minima and the saddle point are connected with a number of saddle node bifurcations. Saddle node bifurcations also emerge in the area of the saddle point of the potential function with periodic orbits which bridge the region between reactant and product channels. These saddle node bifurcations appear in a regular pattern with their critical energies of generation converging to a limiting value. Each successive saddle node bifurcation contains periodic orbits which increase by one the number of turning points in the reactant channel.

Founargiotakis, M.; Farantos, S. C.; Skokos, Ch.; Contopoulos, G.

1997-10-01

226

Stochastic resonance in a periodic potential system under a constant force

International Nuclear Information System (INIS)

An overdamped particle moving in a periodic potential, and subject to a constant force and a stochastic force (i.e., ? = -sin(2??) + B + ?(t),?(t) is a white noise) is considered. The mobility of the particle, d/dt, is investigated. The stochastic resonance type of behaviour is revealed. The study of the SR problem can thus be extended to systems with periodic force. (author). 13 refs

227

Synchronization under periodic modulation of potential wells in a two-state stochastic system

We analyse the effect of synchronization between noise and periodic signal in a two-state spatially extended system analytically. Resonance features are demonstrated. To have the maximum cooperation between signal and noise, it is shown that noise strength at resonance should increase linearly with the frequency of the signal. The time scale of the process at resonance is also shown to increase linearly with the period of the signal.

Dhara, Asish K.; Banerjee, S. R.

1999-01-01

228

The analog channel periodic test of protect system in Qinshan second nuclear power plant

International Nuclear Information System (INIS)

The thesis introduced the essentiality and principle of the analog channel periodic test of protect system (for short the T1 periodic test hereinafter) in Qinshan Nuclear Power Phase II, including the composing of the T1 test unit, and summarized the trouble during the unit debugging and commercial operation.At the same time,it points out the analysis and solving measures to the trouble. There is positive meaning to lower the risk in later work in nuclear power plant. (authors)

229

In the previous paper \\cite{J1}, we established pointwise bounds for the Green function of the linearized equation associated with spatially periodic traveling waves $\\bar u$ of a system of reaction diffusion equations, and also obtained pointwise nonlinear stability and behavior of $\\bar u$ under small perturbations. In this paper, using periodic resolvent kernels and the Bloch-decomposition, we establish pointwise bounds for the Green function of the linearized equation as...

Jung, Soyeun

2012-01-01

230

Periodic Solutions to Painlev\\'e VI and Dynamical System on Cubic Surface

The number of periodic solutions to Painlev\\'e VI along a Pochhammer loop is counted exactly. It is shown that the number grows exponentially with period, where the growth rate is determined explicitly. Principal ingredients of the computation are a moduli-theoretical formulation of Painlev\\'e VI, a Riemann-Hilbert correspondence, the dynamical system of a birational map on a cubic surface, and the Lefschetz fixed point formula.

Iwasaki, K; Iwasaki, Katsunori; Uehara, Takato

2005-01-01

231

Existence and global stability of positive periodic solutions of a discrete delay competition system

The existence and the global stability of positive periodic solutions of a discrete competition model is studied. The model incorporates time delays and allows for a fluctuating environment. By means of some standard procedures of the topological degree method and the construction of a suitable Lyapunov function, sufficient conditions are obtained to ensure the existence and the global stability of positive periodic solutions of the above systems.

Wan-Tong Li; Hai-Feng Huo

2003-01-01

232

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

233

Periodic Solutions of the Vlasov-Poisson System with Boundary Conditions

We study the Vlasov-Poisson system with time periodic boundary conditions. For small data we prove existence of weak periodic solutions in any space dimension. In the one dimensional case the result is stronger: we obtain existence of mild solution and uniqueness of this solution when the data are smooth. It is necessary to impose a non vanishing condition for the incoming velocities in order to control the life-time of particles in the domain.

Bostan, Mihai; Poupaud, Fre?de?ric

1998-01-01

234

In this paper, for any positive integer $n$, we study the Maslov-type index theory of $i_{L_0}$, $i_{L_1}$ and $i_{\\sqrt{-1}}^{L_0}$ with $L_0=\\{0\\}\\times \\R^n\\subset \\R^{2n}$ and $L_1=\\R^n\\times \\{0\\} \\subset \\R^{2n}$. As applications we study the minimal period problems for brake orbits of nonlinear autonomous reversible Hamiltonian systems. For first order nonlinear autonomous reversible Hamiltonian systems in $\\R^{2n}$, which are semipositive, and superquadratic at zero and infinity, we prove that for any $T>0$, the considered Hamiltonian systems possesses a nonconstant $T$ periodic brake orbit $X_T$ with minimal period no less than $\\frac{T}{2n+2}$. Furthermore if $\\int_0^T H"_{22}(x_T(t))dt$ is positive definite, then the minimal period of $x_T$ belongs to $\\{T,\\;\\frac{T}{2}\\}$. Moreover, if the Hamiltonian system is even, we prove that for any $T>0$, the considered even semipositive Hamiltonian systems possesses a nonconstant symmetric brake orbit with minimal period belonging to $\\{T,\\;\\frac{T}{3}\\}$

Zhang, Duanzhi

2011-01-01

235

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

236

We present period change rates (dP/dt) for 42 RR Lyrae variables in the globular cluster IC$\\,$4499. Despite clear evidence of these period increases or decreases, the observed period change rates are an order of magnitude larger than predicted from theoretical models of this cluster. We find there is a preference for increasing periods, a phenomenon observed in most RR Lyrae stars in Milky Way globular clusters. The period-change rates as a function of position in the period-amplitude plane are used to examine possible evolutionary effects in OoI clusters, OoII clusters, field RR Lyrae stars and the mixed-population cluster $\\omega$~ Centauri. It is found that there is no correlation between the period change rate and the typical definition of Oosterhoff groups. If the RR Lyrae period changes correspond with evolutionary effects, this would be in contrast to the hypothesis that RR Lyrae variables in OoII systems are evolved HB stars that spent their ZAHB phase on the blue side of the instability strip. This ...

Kunder, Andrea; Stetson, Peter B; Bono, Giuseppe; Nemec, James M; de Propris, Roberto; Monelli, Matteo; Cassisi, Santi; Andreuzzi, Gloria; Dall'Ora, Massimo; Di Cecco, Alessandra; Zoccali, Manuela

2010-01-01

237

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. Tval 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

238

Stochastic period-doubling bifurcation analysis of a Roessler system with a bounded random parameter

International Nuclear Information System (INIS)

This paper aims to study the stochastic period-doubling bifurcation of the three-dimensional Roessler system with an arch-like bounded random parameter. First, we transform the stochastic Roessler system into its equivalent deterministic one in the sense of minimal residual error by the Chebyshev polynomial approximation method. Then, we explore the dynamical behaviour of the stochastic Roessler system through its equivalent deterministic system by numerical simulations. The numerical results show that some stochastic period-doubling bifurcation, akin to the conventional one in the deterministic case, may also appear in the stochastic Roessler system. In addition, we also examine the influence of the random parameter intensity on bifurcation phenomena in the stochastic Roessler system. (general)

239

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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

240

Effect of dielectric responses on localization in 1D random periodic-on-average systems

Dielectric response effects on wave localization in random periodic-on-average layered systems (POAS) are studied. Based on Monte Carlo simulations and products of Random Matrices, statistics of the Lyapunovmexponent are determined efficiently for very long systems. A novel oscillatory behavior for the Lyapunov exponent is found and explained for mildly strong scattering conditions. We also show the emergence of strongly localized states in metallic layered systems with inte...

Wang, Cheng-ching; Luan, Pi-gang

2001-01-01

241

Recently, we have proposed a technique for the computation of periodic orbits in molecular systems, based on the characteristic bisection method [Vrahatis et al., Comput. Phys. Commun. 138 (2001) 53]. The main advantage of the characteristic bisection method is that it converges with certainty within a given starting rectangular region. In this paper we further improve this technique by applying, on a surface of section of a Poincaré map, an iterative scheme based on the composition of the characteristic bisection method with other more rapid root-finding methods such as Newton's or Broyden's methods. Thus, the composite schemes compute rapidly with certainty periodic orbits of molecular systems. By applying these methods to the LiNC/LiCN molecular system we obtain promising results. We have reproduced previous results using considerable less CPU time. Also, we have located and computed new asymmetric families of periodic orbits.

Perdiou, A. E.; Kalantonis, V. S.; Perdios, E. A.; Vrahatis, M. N.

2002-10-01

242

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

243

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

244

On the periodic solutions of linear homogenous systems of differential equations

Directory of Open Access Journals (Sweden)

Full Text Available Given a fundamental matrix ÃÂ•(x of an n-th order system of linear homogeneous differential equations YÃ¢Â€Â²=A(xY, a necessary and sufficient condition for the existence of a k-dimensional (kÃ¢Â‰Â¤n periodic sub-space (of period T of the solution space of the above system is obtained in terms of the rank of the scalar matrix ÃÂ•(tÃ¢ÂˆÂ’ÃÂ•(0.

A. K. Bose

1982-06-01

245

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)

246

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

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

247

Bifurcation for Second-Order Hamiltonian Systems with Periodic Boundary Conditions

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Full Text Available Through variational methods, we study nonautonomous systems of second-order ordinary differential equations with periodic boundary conditions. First, we deal with a nonlinear system, depending on a function u, and prove that the set of bifurcation points for the solutions of the system is not ÃÂƒ-compact. Then, we deal with a linear system depending on a real parameter ÃŽÂ»>0 and on a function u, and prove that there exists ÃŽÂ»Ã¢ÂˆÂ— such that the set of the functions u, such that the system admits nontrivial solutions, contains an accumulation point.

Francesca Faraci

2008-02-01

248

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

249

Structure and magnetic field of periodic permanent magnetic focusing system with open magnetic rings

Energy Technology Data Exchange (ETDEWEB)

The magnetic field along the central axis for an axially magnetized permanent magnetic ring was investigated by analytical and finite element methods. For open magnetic rings, both calculated and measured results show that the existence of the radial magnetic field creates a remarkable cosine distribution field along the central axis. A new structure of periodic permanent magnet focusing system with open magnetic rings is proposed. The structure provides a satisfactory magnetic field with a stable peak value of 120 mT for a traveling wave tube system. - Research highlights: For open magnetic rings, both calculated and measured results show that the existence of the radial magnetic field creates a remarkable cosine distribution field along the central axis. A new structure of periodic permanent magnet (PPM) focusing system with open magnetic rings is proposed. The new PPM focusing system with open magnetic rings meets the requirements for TWT system.

Peng Long, E-mail: plxkd@sina.co [College of Optoelectronics Technology, Chengdu University of Information Technology, Chengdu 610225 (China); Li Lezhong; Yang Dingyu; Zhu Xinghua [College of Optoelectronics Technology, Chengdu University of Information Technology, Chengdu 610225 (China); Li Yuanxun [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

2011-06-15

250

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 statistical analysis predicts ~17 such pairs. For orbital periods of the inner planet that are less than three days, the minimum period ratio ...

Steffen, Jason H.; Farr, Will

2013-01-01

251

NSVS4484038, a Contact Binary System at the Short-period Cutoff

We present a photometric study of the short-period eclipsing binary NSVS4484038. Time-series CCD photometry of the star in the B and V band was carried out. An orbital period of 0.218551 days was determined for the eclipsing binary and a revised linear ephemeris was given. The first photometric solution of the binary system was detected through light-curve synthesis using the Wilson-Devinney method. It reveals an overcontact configuration for the system with a filling-out factor of about 10%. The mass ratio was determined to be 2.74 with an inclination of 72.°1. The less massive secondary component is found to have a higher surface temperature than the primary by about 90 K, indicating that NSVS4484038 could be a contact system of W subtype. The star is then identified to be a new member of W UMa systems at the short-period cutoff. Comparisons with known contact binaries at the short-period cutoff, the properties, and the evolutionary status of the binary system are discussed.

Zhang, X. B.; Deng, L. C.; Wang, K.; Yan, Z. Z.; Tian, J. F.; Peng, Y. J.; Pan, Y.; Luo, Z. Q.; Sun, J. J.; Liu, Q. L.; Xin, H. Q.; Zhou, Q.

2014-09-01

252

Control of stochastic resonance in bistable systems by using periodic signals

International Nuclear Information System (INIS)

According to the characteristic structure of double wells in bistable systems, this paper analyses stochastic fluctuations in the single potential well and probability transitions between the two potential wells and proposes a method of controlling stochastic resonance by using a periodic signal. Results of theoretical analysis and numerical simulation show that the phenomenon of stochastic resonance happens when the time scales of the periodic signal and the noise-induced probability transitions between the two potential wells achieve stochastic synchronization. By adding a bistable system with a controllable periodic signal, fluctuations in the single potential well can be effectively controlled, thus affecting the probability transitions between the two potential wells. In this way, an effective control can be achieved which allows one to either enhance or realize stochastic resonance

253

Directory of Open Access Journals (Sweden)

Full Text Available A point mapping analysis is employed to investigate the stability of periodic systems. The method is applied to simplified rotorcraft models. The proposed approach is based on a procedure to obtain an analytical expression for the period-to-period mapping description of system's dynamics, and its dependence on system's parameters. Analytical stability and bifurcation conditions are then determined and expressed as functional relations between important system parameters. The method is applied to investigate the parametric stability of flapping motion of a rotor and the ground resonance problem encountered in rotorcraft dynamics. It is shown that the proposed approach provides very accurate results when compared with direct numerical results which are assumed to be an “exact solution” for the purpose of this study. It is also demonstrated that the point mapping method yields more accurate results than the widely used classical perturbation analysis. The ability to perform analytical stability studies of systems with multiple degrees-of-freedom is an important feature of the proposed approach since most existing analysis methods are applicable to single degree-of-freedom systems. Stability analysis of higher dimensional systems, such as the ground resonance problems, by perturbation methods is not straightforward, and is usually very cumbersome.

Flashner Henryk

1997-01-01

254

Condition for emergence of the Floquet-Gibbs state in periodically driven open systems

We study probability distribution of a steady state of a periodically driven system coupled to a thermal bath by using a quantum master equation in the weak-coupling limit. It is proved that, even when the external field is strong, the probability distribution is independent of the detailed nature of the thermal bath under the following conditions: (i) the Hamiltonian of the relevant system is bounded and the period of the driving field is short, (ii) the Hamiltonians for the driving field at different times commute, and (iii) the Hamiltonians of the driving field and of the interaction between the relevant system and the thermal bath commute. It is shown that the steady state is described by the Gibbs distribution of the Floquet states of the relevant system at the temperature of the thermal bath.

Shirai, Tatsuhiko; Mori, Takashi; Miyashita, Seiji

2015-03-01

255

Czech Academy of Sciences Publication Activity Database

Ro?. 112, May 22 (2012), s. 1-23. ISSN 1025-5834 Institutional support: RVO:67985840 Keywords : periodic problem * linear functional differential system * non-negative solution Subject RIV: BA - General Mathematics Impact factor: 0.879, year: 2010 http://www.journalofinequalitiesandapplications.com/content/2012/1/112

Domoshnitsky, A.; Hakl, Robert; Šremr, Ji?í

2012-01-01

256

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

257

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

258

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

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

259

On the Riesz Basisness of Systems Composed of Root Functions of Periodic Boundary Value Problems

In this paper, we consider the nonselfadjoint Sturm Liouville operator with and either periodic, or antiperiodic boundary conditions. We obtain necessary and sufficient conditions for systems of root functions of these operators to be a Riesz basis in in terms of the Fourier coefficients of q.

Kirac, Alp Arslan

2014-01-01

260

Infrared photometry of the RS CVn short-period systems - XY UMa and WY Cnc

International Nuclear Information System (INIS)

Infrared J and K light curves of two RS CVn short-period systems, XY UMa and WY Cnc, are presented. Both systems show similar variability in the infrared to that observed in the visual. From the colors an infrared excess is inferred for the primary component of both systems. A new determination of their geometrical elements is presented and the resulting parameters are compared to those previously obtained from visible photometry. The light curves show peculiarities that may indicate the presence of gas streams in the systems. 27 refs

261

Bifurcation for Second-Order Hamiltonian Systems with Periodic Boundary Conditions

Through variational methods, we study nonautonomous systems of second-order ordinary differential equations with periodic boundary conditions. First, we deal with a nonlinear system, depending on a function u, and prove that the set of bifurcation points for the solutions of the system is not ÃÂƒ-compact. Then, we deal with a linear system depending on a real parameter ÃŽÂ»>0 and on a function u, and prove that there exists ÃŽÂ»Ã¢ÂˆÂ— such that the set of the functions u, ...

Francesca Faraci; Antonio Iannizzotto

2008-01-01

262

International Nuclear Information System (INIS)

In the paper, the variable separation approach, homoclinic test technique and bilinear method are successfully extended to a (1 + 1)-dimensional Caudry-Dodd-Gibbon-Sawada-Kortera (CDGSK) system, respectively. Based on the derived exact solutions, some significant types of localized excitations such as standing waves, periodic waves, solitary waves are simultaneously derived from the (1 + 1)-dimensional Caudry-Dodd-Gibbon-Sawada-Kortera system by entrancing appropriate parameters. (general)

263

We study the residence time distributions and explore the possibility of observing stochastic resonance and synchonization of passages in a two-well system driven by a periodic forcing of amplitude larger than a marginal value beyond which one of the two wells become unstable and diasppear. We define and calculate hysteresis loop in the system, the area of which measures the degree of synchronization between the residence time statistics and the input signal, as a function o...

Mahato, Mangal C.; Jayannavar, A. M.

1997-01-01

264

Quantum Intermittency in Almost-Periodic Lattice Systems Derived from their Spectral Properties

Hamiltonian tridiagonal matrices characterized by multi-fractal spectral measures in the family of Iterated Function Systems can be constructed by a recursive technique here described. We prove that these Hamiltonians are almost-periodic. They are suited to describe quantum lattice systems with nearest neighbours coupling, as well as chains of linear classical oscillators, and electrical transmission lines. We investigate numerically and theoretically the time dynamics of ...

Mantica, Giorgio

1996-01-01

265

Self-isospectral tri-supersymmetry in PT-symmetric quantum systems with pure imaginary periodicity

We study a reflectionless PT-symmetric quantum system described by the pair of complexified Scarf II potentials mutually displaced in the half of their pure imaginary period. Analyzing the rich set of intertwining discrete symmetries of the pair, we find an exotic supersymmetric structure based on three matrix differential operators that encode all the properties of the system, including its reflectionless (finite-gap) nature. The structure we revealed particularly sheds new...

Correa, Francisco; Plyushchay, Mikhail S.

2012-01-01

266

Sign reversal of drag in bilayer systems with in-plane periodic potential modulation

DEFF Research Database (Denmark)

We develop a theory for describing frictional drag in bilayer systems with in-plane periodic potential modulations, and use it to investigate the drag between bilayer systems in which one of the layers is modulated in one direction. At low temperatures, as the density of carriers in the modulated layer is changed, we show that it is possible for the transresistivity component in the direction of modulation to change its sign. We also give a physical explanation for this behavior.

Alkauskas, A.; Flensberg, Karsten

2002-01-01

267

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

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

268

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

269

DEFF Research Database (Denmark)

Recently, several authors have investigated topological phenomena in periodically driven systems of noninteracting particles. These phenomena are identified through analogies between the Floquet spectra of driven systems and the band structures of static Hamiltonians. Intriguingly, these works have revealed phenomena that cannot be characterized by analogy to the topological classification framework for static systems. In particular, in driven systems in two dimensions (2D), robust chiral edge states can appear even though the Chern numbers of all the bulk Floquet bands are zero. Here, we elucidate the crucial distinctions between static and driven 2D systems, and construct a new topological invariant that yields the correct edge-state structure in the driven case. We provide formulations in both the time and frequency domains, which afford additional insight into the origins of the “anomalous” spectra that arise in driven systems. Possibilities for realizing these phenomena in solid-state and cold-atomic systems are discussed.

Rudner, Mark Spencer; Lindner, Netanel

2013-01-01

270

New quasi-periodic waves and theirs interactions in (2 + 1)-dimensional nonlinear systems

International Nuclear Information System (INIS)

In this study the general variable separated approach is successfully extended to the (2 + 1)-dimensional physical model. An universal formula involving arbitrary number of variable separated functions is obtained. Because of the existence of the arbitrary functions in the universal formula, new exact quasi-periodic and non-periodic solutions for the (2 + 1)-dimensional nonlinear systems are demonstrated both analytically and graphically by means of the Jacobi elliptic functions with the space-time-dependent modulus. Some novel features or interesting behaviors are revealed.

271

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

272

We present a density fitted local configuration interaction singles (CIS) method for calculating optical bandgaps in 3D-periodic systems. We employ an Ewald technique to carry out infinite lattice summations for the exciton-exciton interaction, and robust product-density specific local density fitting in direct space for the electron-hole interaction. Moreover, we propose an alternative to the usual cyclic model with Born-von Karman periodic boundary conditions, the so called Wigner-Seitz supercell truncated infinite model, which exhibits much improved convergence of the CIS excitation energy with respect to the size of the supercell. Test calculations on a series of prototypical systems demonstrate that the method at the present stage can be used to calculate the excitonic bandgaps of 3D periodic systems with up to a dozen atoms in the unit cell, ranging from wide-gap insulators to semiconductors. PMID:23205993

Lorenz, Marco; Maschio, Lorenzo; Schütz, Martin; Usvyat, Denis

2012-11-28

273

Multistability and stable asynchronous periodic oscillations in a multiple-delayed neural system

We consider a network of three identical neurons with multiple discrete signal transmission delays. The model for such a network is a system of nonlinear delay differential equations. After some consideration of the absolute synchronization of the system and the global attractivity of the zero solution, we present a detailed discussion about the boundaries of the stability region of the trivial solution. This allows us to determine the possible codimension one bifurcations which occur in the system. In particular, we show the existence of standard Hopf bifurcations giving rise to synchronized periodic solutions and of D3 equivariant Hopf bifurcations giving rise to three types of periodic solutions: phase-locked, mirror-reflecting, and standing waves. Hopf-Hopf and Hopf-steady state bifurcations interactions are shown to exist and give rise to coexistence of stable synchronized and desynchronized solutions. Perturbation techniques coupled with the Floquet theory are used to determine the stability of the phase-locked oscillations.

Campbell, S. A.; Ncube, I.; Wu, J.

2006-02-01

274

Chaotic dynamics of one-dimensional systems with periodic boundary conditions.

We provide appropriate tools for the analysis of dynamics and chaos for one-dimensional systems with periodic boundary conditions. Our approach allows for the investigation of the dependence of the largest Lyapunov exponent on various initial conditions of the system. The method employs an effective approach for defining the phase-space distance appropriate for systems with periodic boundaries and allows for an unambiguous test-orbit rescaling in the phase space required to calculate the Lyapunov exponents. We elucidate our technique by applying it to investigate the chaotic dynamics of a one-dimensional plasma with periodic boundaries. Exact analytic expressions are derived for the electric field and potential using Ewald sums, thereby making it possible to follow the time evolution of the plasma in simulations without any special treatment of the boundary. By employing a set of event-driven algorithms, we calculate the largest Lyapunov exponent, the radial distribution function, and the pressure by following the evolution of the system in phase space without resorting to numerical manipulation of the equations of motion. Simulation results are presented and analyzed for the one-dimensional plasma with a view to examining the dynamical and chaotic behavior exhibited by small and large versions of the system. PMID:25615175

Kumar, Pankaj; Miller, Bruce N

2014-12-01

275

International Nuclear Information System (INIS)

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 statistical analysis 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?P2/P1?>2.3 (P1/day)-2/3. This absence 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 three days over the number of multiple candidate systems with similar periods—perhaps a small-planet counterpart to the hot Jupiters

276

We carried out photometric and low-resolution spectral observations of six eclipsing ultrashort-period binaries with MS components. The light curve solutions of the Rozhen observations show that all targets are overcontact systems. We found well-defined empirical relation "period -- semi-major axis" for the short-period binaries and used it for estimation of the global parameters of the targets. Our results revealed that NSVS 925605 is quite interesting target: (a) it is one of a few contact binaries with M components; (b) it exhibits high activity (emission in H$\\alpha$ line, X-ray emission, large cool spots, non-Planck energy distribution); (c) its components differ in temperature by 700 K. All appearances of high magnetic activity and huge fillout factor (0.7) of NSVS 925605 might be assumed as a precursor of the predicted merging of close magnetic binaries. Another unusual binary is NSVS 2700153 which reveals considerable long-term variability.

Dimitrov, Dinko

2015-01-01

277

Period ratios in multi-planetary systems discovered by Kepler are consistent with planet migration

The Kepler planet candidates are an interesting testbed for planet formation scenarios. We present results from N-body simulations of multi-planetary systems that resemble those observed by Kepler. We add both smooth (Type I/II) and stochastic migration forces. The observed period ratio distribution is inconsistent with either of those two scenarios on its own. However, applying both stochastic and smooth migration forces to the planets simultaneously results in a period ratio distribution that is similar to the observed one. This is a natural scenario if planets form in a turbulent proto-planetary disk where these forces are always present. We show how the observed period ratio and eccentricity distribution can constrain the relative strength of these forces, a parameter which has been notoriously hard to predict for decades. We make the source code of our simulations and the initial conditions freely available to enable the community to expand this study and include effect other than planetary migration.

Rein, Hanno

2012-01-01

278

Lifetime and reliability estimation of repairable redundant system subject to periodic alternation

International Nuclear Information System (INIS)

Lifetime distribution and reliability are analyzed for redundant systems consisting of units that alternate between operating and standby states periodically to inspect and detect failures of standby units. It is assumed that when a unit fails, a minimal repair with negligible repair time is performed. A cumulative exposure model is used to describe the failure time distribution. The method of maximum likelihood is used to estimate the parameters, and specific formulas for Weibull model are obtained. A simulation model is then developed to assess the system reliability based on the estimated lifetime distribution and the method is applied to a high pressure pump system

279

Effect of dielectric responses on localization in 1D random periodic-on-average systems

Dielectric response effects on wave localization in random periodic-on-average layered systems (POAS) are studied. Based on Monte Carlo simulations and products of Random Matrices, statistics of the Lyapunov exponent are determined efficiently for very long systems. A novel oscillatory behavior for localization is found and explained for mildly strong scattering conditions. We also show the emergence of strongly localized states in metallic layered systems with intermediate disorder for frequencies above the plasma frequency $\\omega_{p}$ of metals, as is not shown in dielectrics. Furthermore, the violation of universal single parameter scaling behaviors in different regimes of multiple scattering is discussed.

Wang Chao Cheng; Wang, Cheng-Ching; Luan, Pi-Gang

2002-01-01

280

Self-isospectral tri-supersymmetry in PT-symmetric quantum systems with pure imaginary periodicity

We study a reflectionless PT-symmetric quantum system described by the pair of complexified Scarf II potentials mutually displaced in the half of their pure imaginary period. Analyzing the rich set of intertwining discrete symmetries of the pair, we find an exotic supersymmetric structure based on three matrix differential operators that encode all the properties of the system, including its reflectionless (finite-gap) nature. The structure we revealed particularly sheds new light on the splitting of the discrete states into two families, related to the bound and resonance states in Hermitian Scarf II counterpart systems, on which two different series of irreducible representations of sl(2,C) are realized.

Correa, Francisco

2012-01-01

281

International Nuclear Information System (INIS)

Stochastic resonance (SR) of a periodically driven time-delayed linear system with multiplicative white noise and periodically modulated additive white noise is investigated. In the condition of small delay time, an approximate analytical expression of output signal-to-noise ratio (SNR) is obtained. The analytical results indicate that (1) there exists a resonance peak in the curve for SNR versus time delay; (2) the time delay will suspend the SR dramatically for SNR versus other parameters of the system, such as noise intensity, correlation intensity, and signal frequency, once a certain value is reached, the SR phenomenon disappears. (general)

282

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

283

Amplification effects on the transmission and reflexion phases in 1D periodic systems

International Nuclear Information System (INIS)

We investigate the localization recently observed for locally non-hermitian Hamiltonians by studying the effect of the amplification on the scaling behavior of the transmission and reflection phases in 1D periodic chains of ?-potentials. The amplification here is represented by an imaginary term added to the on-site potential. It is found that both phases of the transmission and reflection amplitudes are strongly affected by the amplification term. In particular, the phases in the region of amplification become independent of the length scale while they oscillate strongly near the maximum transmission (or reflection). The interference effects on the phase in passive systems are used to interpret those observed in the presence of amplification. The phases of the transmission and reflection are found to oscillate in passive systems with increasing periods in the allowed band for the transmission phase while for the reflection phase, its initial value is always less than ?/2 in this band. (author)

284

BeppoSAX observations of the long period polar system V1309 Ori

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

285

On the Eccentricity Distribution of Short-Period Single-Planet Systems

We apply standard Markov chain Monte Carlo (MCMC) analysis techniques for 50 short- period, single-planet systems discovered with radial velocity technique. We develop a new method for accessing the significance of a non-zero orbital eccentricity, namely {\\Gamma} analysis, which combines frequentist bootstrap approach with Bayesian analysis of each simulated data set. We find the eccentricity estimations from {\\Gamma} analysis are generally consistent with results from both standard MCMC analysis and previous references. The {\\Gamma} method is particular useful for assessing the significance of small eccentricities. Our results suggest that the current sample size is insufficient to draw robust conclusions about the roles of tidal interaction and perturbations in shaping the eccentricity distribution of short-period single-planet systems. We use a Bayesian population analysis to show that a mixture of analytical distributions is a good approximation of the underlying eccentricity distribution. For short-perio...

Wang, Ji

2011-01-01

286

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.)

287

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

288

International Nuclear Information System (INIS)

Mechanisms by which focusing-lens nonlinearities can cause emittance growth or particle loss have been investigated using PIC simulations of a simplified, azimuthally symmetric, period focusing system. Any emittance growth associated with the rapid relaxation of the transverse current distribution to the minimum energy state appropriate to the external forces, including nonlinearities, is typically followed by the less rapid emittance growth which can result from the conversion of any mismatch energy to beam temperature. On a longer time scale, for sufficient nonlinearity, particle orbits can become unstable and particles spiral out of the system. For parameters which are typical of the relatively short transport systems which characterize induction linac drivers, these preliminary results appear to indicate the possibility of utilizing focusing systems with appreciable nonlinearities, provided the beam is rms-matched to the nonlinear transport system. (orig.)

289

Phase velocity and phase diffusion in periodically driven discrete state systems

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

290

Input-output feedback linearization provides a convenient means of extending linear control strategies such as output zeroing or pole placement to the case of nonlinear affine in the input systems, but such extensions cannot be applied in the presence of nonminimum phase characteristics. This paper overcomes this difficulty through the periodic use of a finite number of synthetic outputs which are so constructed as to define embedded dynamics with stable zero dynamics. The efficacy of the met...

Il Lee, Y.; Kouvaritakis, B.; Cannon, M.

2008-01-01

291

We extend the method of Silvestrelli [P. L. Silvestrelli, J. Chem. Phys. 139, 054106 (2013)] to approximate long-range van der Waals interactions at the density functional theory level based on maximally localized Wannier functions combined with the quantum harmonic oscillator model, to periodic systems. Applying this scheme to study London dispersion forces between graphene and water layers, we demonstrate that collective many-body effects beyond simple additive pair-wise interactions are essential to accurately describe van der Waals forces.

Partovi-Azar, Pouya

2015-01-01

292

We develop a practical method of computing the stationary drift velocity V and the diffusion coefficient D of a particle (or a few particles) in a periodic system with arbitrary transition rates. We solve this problem both in a physically relevant continuous-time approach as well as for models with discrete-time kinetics, which are often used in computer simulations. We show that both approaches yield the same value of the drift, but the difference between the diffusion coef...

Koza, Zbigniew

1999-01-01

293

Swift computation of the periodic steady state solution of power systems containing TCSCs

Energy Technology Data Exchange (ETDEWEB)

In this contribution a state space model of the TCSC is described. The periodic steady state solution of the entire power system is efficiently obtained in the time domain with the application of a Newton method based on a numerical differentiation procedure. The solution is compared in terms of accuracy and efficiency against the solution obtained with a conventional brute force method based on the fourth order Runge-Kutta numerical integration method. (author)

Medina, A.; Ramos-Paz, A.; Fuerte-Esquivel, C.R. [Ciudad Universitaria Morelia (Mexico). Facultad de Ingenieria Electrica

2003-11-01

294

Interband coherence induced correction to adiabatic pumping in periodically driven systems

Periodic driving can create topological phases of matter absent in static systems. In terms of the displacement of the position expectation value of a time-evolving wave packet in a closed system, a type of adiabatic dynamics in periodically driven systems is studied for general initial states possessing coherence between different Floquet bands. Under one symmetry assumption, the displacement of the wave-packet center over one adiabatic cycle is found to consist of two components independent of the time scale of the adiabatic cycle: a weighted integral of the Berry curvature summed over all Floquet bands, plus an interband coherence induced correction. The found correction is beyond a naive application of the quantum adiabatic theorem but survives in the adiabatic limit due to interband coherence. Our theoretical results are hence of general interest towards an improved understanding of the quantum adiabatic theorem. Our theory is checked using a periodically driven superlattice model with nontrivial topological phases. In addition to probing topological phase transitions, the adiabatic dynamics studied in this work is now also anticipated to be useful in manifesting coherence and decoherence effects in the representation of Floquet bands.

Wang, Hailong; Zhou, Longwen; Gong, Jiangbin

2015-02-01

295

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

International Nuclear Information System (INIS)

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 ?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 RJ , and as small as 0.79 RJ .

296

Hysteresis effect in the ?=1 quantum Hall system under periodic electrostatic modulation

International Nuclear Information System (INIS)

The effect of a one-dimensional periodic electrostatic modulation on quantum Hall systems with filling factor ?=1, is studied. We propose that, either when the amplitude of the modulation potential or the tilt angle of the magnetic field is varied, the system can undergo a first-order phase transition from a fully spin-polarized homogeneous state to a partially spin-polarized charge-density-wave state, and show hysteresis behavior of the spin polarization. This is confirmed by our self-consistent numerical calculations within the Hartree-Fock approximation

297

Period changes in a close binary system with mass and angular momentum loss

International Nuclear Information System (INIS)

The parameters of a close binary system with mass exchange between components and the primary filling its Roche lobe are estimated in the restricted three-body approximation. Gasodynamics of the mass transfer and processes in star interiors depending on it are not considered. It is assumed that the angular momentum of the exchaned matter entering the Roche lobe of the secondary is carried away from the system. The computed mass and momentum losses, the distance between component centers and the orbital period are different from the results obtained previously using another model of the mass transfer. (author)

298

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)

299

Selection of detailed items for periodic safety review on PWR radwaste management system

International Nuclear Information System (INIS)

Selection of detailed-items for Periodic Safety Review on PWR radwaste management system, the main component could be faithfully clarified according to the purpose of establishment on each system and basic purpose. It is proper to select detailed-items those of radioactivities in the reactor coolant activity levels and the released volume of liquid and gaseous radioactive material on safety performance. It's also proper to select solid radwaste production quantities as detailed-item that it would be predict the next ten years trends after PSR

300

A study on the periodic safety review of electrical system for operating nuclear power plants

International Nuclear Information System (INIS)

In Korea, the Periodic Safety Review(PSR) is being performed one by one for all the operating nuclear power plants in compliance with domestic nuclear regulations. This paper is to introduce the methodology of PSR and the status of the aging management programs for the electrical system of operating nuclear power plants. Especially active components performance evaluation using probabilistic method is added in this PSR. It is found that aging management programs for electrical system are adequate to maintain plant safety during next ten years

301

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

302

Linear response as a singular limit for a periodically driven closed quantum system

International Nuclear Information System (INIS)

We address the issue of the validity of linear response theory for a closed quantum system subject to a periodic external driving. Linear response theory (LRT) predicts energy absorption at frequencies of the external driving where the imaginary part of the appropriate response function is different from zero. Here we show that, for a fairly general nonlinear many-body system on a lattice subject to an extensive perturbation, this approximation should be expected to be valid only up to a time t* depending on the strength of the driving, beyond which the true coherent Schrödinger evolution departs from the linear response prediction and the system stops absorbing energy from the driving. We exemplify this phenomenon in detail with the example of a quantum Ising chain subject to a time-periodic modulation of the transverse field, by comparing an exact Floquet analysis with the standard results of LRT. In this context, we also show that if the perturbation is just local, the system is expected in the thermodynamic limit to keep absorbing energy, and LRT works at all times. We finally argue more generally the validity of the scenario presented for closed quantum many-body lattice systems with a bound on the energy-per-site spectrum, discussing the experimental relevance of our findings in the context of cold atoms in optical lattices and ultra-fast spectroscopy experiments. (paper)

303

Evaluation of raw milk quality in different production systems and periods of the year

Scientific Electronic Library Online (English)

Full Text Available The objective of this study was to evaluate the quality of raw milk in different production systems and its variation throughout the year. The data were collected from 943 dairy farms in the South, Central-West and Central regions of the state of Minas Gerais, and in Vale do Paraíba, in the state of [...] São Paulo, Brazil. The data were collected in the period from January 2009 to September 2011, in a total of 18,206 samples. The properties were divided into confinement, semi-confinement and extensive production systems. The evaluated factors were somatic cell count (SCC), total bacterial count (TBC) and protein and fat contents. There was no effect of production system on the contents of protein, fat and SCC. Total bacterial count, however, was affected by production. Seasonal variations were found for SCC, TBC, protein and fat; the highest protein values were found from March to June; the highest fat contents were obtained from May to August; and TBC and SCC, from December to March. The production system does not interfere with the percentage of fat and protein and SCC of the milk. However, confinement systems present a better TBC content. Both month and year are factors that interfere with TBC, SCC, protein and milk fat, and the best patterns are found in the coldest periods of the year.

Marcos Inácio, Marcondes; Daniele Canabrava, Jácome; Alex Lopes da, Silva; Luciana Navajas, Rennó; Ana Clarissa dos Santos, Pires.

2014-12-01

304

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

305

'Calculation chemistry' of the heavy elements; comparison with elements of the 7th period

International Nuclear Information System (INIS)

Increasing deviations from Mendeleev-type periodicity of chemical properties is predicted for elements as their atomic number exceeds 100. Relativistic Dirac-Fock calculations indicate that the periodicity of electronic binding energies of elements becomes increasingly 'non-monotonic' as Z increases. Changes in electronic levels include: increasing binding of s and psub(1/2) electrons, decreased binding of psub(3/2) electrons, increased radial extension and lowered ionization energies of d orbitals vs. s. Evidence is cited that such changes are already observable in known elements, particularly those of the seventh period. Prediction of aqueous valences for the trans-lawrencium elements is made. The first ionization of elements 103 to 112 involves, in every case, removal of 6d electrons rather than 7s. Ready removal of psub(3/2) electrons, breaking the rare gas shell of 119+, should allow valences greater than one of this 'alkali metal'. (author)

306

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

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

307

Mean first-passage times for systems driven by equilibrium persistent-periodic dichotomous noise

International Nuclear Information System (INIS)

In a recent paper, [J. M. Porra, J. Masoliver, and K. Lindenberg, Phys. Rev. E 48, 951 (1993)], we derived the equations for the mean first-passage time for systems driven by the coin-toss square wave, a particular type of dichotomous noisy signal, to reach either one of two boundaries. The coin-toss square wave, which we here call periodic-persistent dichotomous noise, is a random signal that can only change its value at specified time points, where it changes its value with probability q or retains its previous value with probability p=1-q. These time points occur periodically at time intervals ?. Here we consider the stationary version of this signal, that is, ''equilibrium'' periodic-persistent noise. We show that the mean first-passage time for systems driven by this stationary noise does not show either the discontinuities or the oscillations found in the case of nonstationary noise. We also discuss the existence of discontinuities in the mean first-passage time for random one-dimensional stochastic maps

308

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

309

Self-isospectral tri-supersymmetry in PT-symmetric quantum systems with pure imaginary periodicity

International Nuclear Information System (INIS)

We study a reflectionless PT-symmetric quantum system described by the pair of complexified Scarf II potentials mutually displaced in the half of their pure imaginary period. Analyzing the rich set of intertwining discrete symmetries of the pair, we find an exotic supersymmetric structure based on three matrix differential operators that encode all the properties of the system, including its reflectionless (finite-gap) nature. The structure we revealed particularly sheds new light on the splitting of the discrete states into two families, related to the bound and resonance states in Hermitian Scarf II counterpart systems, on which two different series of irreducible representations of sl(2,C) are realized. - Highlights: ? A two-parametric family of pairs of reflectionless self-isospectral PT-symmetric systems is studied. ? A new exotic supersymmetric structure based on three integrals of motion is found. ? The splitting of the discrete states into two families is explained. ? The role of various discrete symmetries and the imaginary period is understood.

310

The BVRI Light Curves And Period Analysis Of The Beta Lyrae System XX Leonis

The contact eclipsing binary system XX Leonis (P = 0.97 days, sp A8) has been analysed using the PHOEBE programme, based on the Wilson Devinney code. The BVRI light curves were obtained during spring 2006 using the 20-cm telescope and ST-7 CCD detector. The effective temperature of the primary component determined from the photometric analysis is T=(7889+/-61)K, the inclination of the orbit is i=(89.98+/-2.45)deg and the photometric mass ratio q=(0.41+/-0.01). Also the third body hypothesis was suggested, based on the period analysis using 57 minimum times and resulting the period of the third body p3= (52.96+/-0.01)yr, amplitude A=(0.057+/-0.029)d and eccentricity e=(0.79+/-0.08) which gives the minimum mass m3,min=(3.6+/-0.8)M_sun.

Zasche, P; Svoboda, P

2007-01-01

311

Health care system of the Republic of Serbia in the period 2004-2012

Directory of Open Access Journals (Sweden)

Full Text Available Introduction. The backbone of Serbian health system forms the public healthcare provider network with 355 institutions and around 112,000 employees, owned and controlled by the Ministry of Health and financed mainly by the Republican Health Insurance Fund. The law recognizes private practice that was not included, till recently, in the public funding scheme. New Health Insurance Law (2005 decreased the number of entitlements in the basic health service package. It abolished the right to dental health care for adults (exceptions are: children, older than 65, pregnant women and emergency cases as well as the right to compensate travel expenses. The aim of this study was to evaluate the effects of health care system of the Republic of Serbia and indicate parameters that determine the state of health of the population, on the ground of data obtained by the Institute of Public Health of Serbia. Results. In the period 2004-2012, cardiovascular diseases represented the main cause of illness in Serbia (50%. In 2012 digestive system diseases were on the second place. Neoplasm and nervous system diseases were on the third place. From 2007 to 2012 there was slight decline in the birth rate and number of deaths, but the death rate increased from 13.9 to 14.2. Health care system in Serbia is funded through the combination of public finances and private contributions. Primary care is provided in 158 health care centres and health care stations, secondary and tertiary care services are offered in general hospitals, specialized hospitals, clinics, clinico-hospital centers and clinical centres. Conclusion. A significant but not satisfactory progress has been achieved in the field of health status indicators as the most important outcome of the final performance of the health system. The transition of public health care system in Serbia since the communist period to present and slow integration with European Union is unfinished process.

Gaji?-Stevanovi? Milena

2014-01-01

312

International Nuclear Information System (INIS)

We consider classical and quantum propagators for two different time intervals. If these propagators follow one another in a Fibonacci sequence we get a discrete quasi-periodic system. A theorem due to Nielsen provides a novel conserved quantity for this system. The Nielsen quantity controls the transition between commutative and non-commutative propagation in time. The quasi-periodically kicked oscillator, moreover, is dominated by quasi-periodic analogues of the Floquet theorem.

313

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.

Johnson, Mathew A.; Zumbrun, Kevin

2010-01-01

314

Stabilizing the unstable periodic orbits of a hybrid chaotic system using optimal control

In this paper, we are interested in the control of a chaotic hybrid system with an application to Chua’s system. It is known that chaotic attractors contain an infinite number of unstable periodic orbits (UPO) with different lengths, our idea consists in stabilizing a predetermined orbit of a given length by using an optimal control method. Our approach is to determine the switching instants from one subsystem to the other while minimizing the difference between two successive orbits. Should the switchings be state dependent, as is the case for the well known Chua’s circuit, then our approach consists in perturbing the switching boundaries such that the system trajectory hits those boundaries at the specified instants. Numerical simulations illustrating the efficiency of the proposed method are presented.

Miladi, Yosra; Feki, Moez; Derbel, Nabil

2015-03-01

315

Quantum Intermittency in Almost-Periodic Lattice Systems Derived from their Spectral Properties

Hamiltonian tridiagonal matrices characterized by multi-fractal spectral measures in the family of Iterated Function Systems can be constructed by a recursive technique here described. We prove that these Hamiltonians are almost-periodic. They are suited to describe quantum lattice systems with nearest neighbours coupling, as well as chains of linear classical oscillators, and electrical transmission lines. We investigate numerically and theoretically the time dynamics of the systems so constructed. We derive a relation linking the long-time, power-law behaviour of the moments of the position operator, expressed by a scaling function $\\beta$ of the moment order $\\alpha$, and spectral multi-fractal dimensions, D_q, via $\\beta(\\alpha) = D_{1-\\alpha}$. We show cases in which this relation is exact, and cases where it is only approximate, unveiling the reasons for the discrepancies.

Mantica, G

1996-01-01

316

Resonance tongues and patterns in periodically forced reaction-diffusion systems

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

317

Periodic orbits analysis of the form factor: from ballistic to diffusive systems

The energy level correlator K(s) and the form factor 0305-4470/29/9/016/img1 are calculated for a hypercubic billiard with small hyperspheres placed at random in its interior. Various regimes, characterized by the elastic mean free path l, resulting from the scattering on impurities, are identified. The analysis extends from the ballistic regime, where l is much larger than the size of the system, via intermediate regimes, to the diffusive regime, where l is much smaller than its size. Semiclassical expressions for the density of states of chaotic and integrable systems in terms of classical periodic orbits are used. The diagonal approximation for 0305-4470/29/9/016/img1 is made for short times, while non-perturbative methods are used for long times. The analysis makes use of analytic properties of classical dynamical zeta function associated with the Perron - Frobenius operator. The general features are relevant for mesoscopic systems.

Agam, Oded; Fishman, Shmuel

1996-05-01

318

Gravity related behavior and the underlying neuronal networks are the most suitable model systems to study basic effects of altered gravitational input on the development of neuronal systems. A feature of sensory and motor systems is their susceptibility to modifications of their adequate physical and/or chemical stimuli during development. This discovery led to the formulation about critical periods, which defines the period of susceptibility during post-embryonal development. Critical periods can be determined by long-lasting modifications of the stimulus input for the gravity sensory system (GSS). Techniques include: (1) destruction of the gravity sense organ so that the gravity cannot be detected any longer and the central neuronal network of the GSS is deprived of gravity related information, (2) loading or deloading of parts of the body by weights or counterweights, respectively, which compensates for the gravitational pull, and (3) absence or augmentation of the gravitational environment per se by the exposure of organisms to microgravity during spaceflights or to hypergravity by centrifugation. Most data came from studies on compensatory eye or head movements in the clawed toad Xenopus laevis, the cichlid fish Oreochromis mossambicus, and crickets (Acheta domesticus, Gryllus bimaculatus). The responses are induced by a roll or pitch stimulation of the gravity sense organs, but are also affected by sensory inputs from proprioreceptors and eyes. The development of these compensatory eye and head responses reveals species-specific time courses. Based on experiments using spaceflights, centrifugation, lesion and loading or deloading, all species revealed a significant susceptibility to modifications of the gravity sensory input during development. Behavioral responses were depressed (Xenopus) or augmented (Xenopus, Oreochronis) by microgravity, and depressed by hypergravity except in crickets. In Acheta, however, the sensitivity of its position sensitive neuron PSI was reduced by microgravity. After termination of the period of modified gravity sensory input, all behavioral and physiological modifications disappeared, in some preparations such as the PSI of Acheta or the eye response in Xenopus, however, delayed after exposure to hypergravity. Irreversible modifications were rare; one example were malformations of the body of Xenopus tadpoles caused by lesion induced deprivation. Several periods of life such as the period of hatching or first appearance of gravity related reflexes revealed a specific sensitivity to altered gravity. Although all studies gave clear evidences for a basic sensitivity of developing GSSs to long-lasting modifications of the gravity sensory input, clear arguments for the existence of a critical period in the development of the sense of gravity are still missing. It has to take into consideration that during long-term exposures, adaptation processes take place which are guided by central physiological and genetically determined set points. The International Space Station (ISS) is the necessary platform of excellence if biological research is focussed on the analysis of long-term space effects on organisms. PMID:14631632

Horn, Eberhard R

2003-01-01

319

Harnessing intrinsic localized modes to identify impurities in nonlinear periodic systems

Intrinsic localized modes (ILMs) are concentrations of vibrational energy in periodic systems/lattices due to the combined influences of nonlinearity and discreteness. Moreover, ILMs can move within the system and may strongly interact with an impurity, such as a stiffness change, mass variation, etc. Numerous scientific fields have uncovered examples and evidence of ILMs, motivating a multidisciplinary pursuit to rigorously understand the underlying principles. In spite of the diverse technical studies, a characterization of ILM interaction behaviors with multiple impurities in dissipative lattices remains outstanding. The insights on such behaviors may be broadly useful when dynamic measurements are the only accessible features of the periodic system. For instance, one may guide an ILM within the lattice using a deliberately applied and steered impurity and harness the observed interaction behaviors with a second, static (immovable) impurity/defect to identify how the underlying lattice is different at the second, defected site, whether or not one knew the position of the defect a priori. In this spirit, this research studies, analyzes, and characterizes the interaction types amongst an ILM and multiple impurities, and devises a method to identify a static defect impurity using quantitatively and qualitatively distinct interaction phenomena. The method is found to be robust to moderate levels of lattice stiffness heterogeneity and is applicable to monitor various property changes that represent impurities. Finally, experimental studies verify that ILMs interact with multiple impurities in unique ways such that defect features may be effectively identified.

Thota, M.; Harne, R. L.; Wang, K. W.

2015-02-01

320

Soliton defects in one-gap periodic system and exotic supersymmetry

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

321

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

322

Surface N Balances in Agricultural Crop production systems in China for the period 1980-2015

Surface nitrogen (N) balances for China's crop production systems were estimated using statistical data collected from 1980 to 2004 at the national and provincial scale and from 1994 to 1999 at the county level. There was a surplus N balance throughout these periods, but the surplus was nearly stable in recent years. Projections using nonseasonal Box-Jenkins model or exponential models show that the N surplus for the total cultivated land in China was likely to increase from 142.8 kg ha¿1 in...

Sun, B.; Shen, R. P.; Bouwman, A. F.

2008-01-01

323

Mean first-passage times for systems driven by equilibrium persistent-periodic dichotomous noise

In a recent paper, [J. M. Porrà, J. Masoliver, and K. Lindenberg, Phys. Rev. E 48, 951 (1993)], we derived the equations for the mean first-passage time for systems driven by the coin-toss square wave, a particular type of dichotomous noisy signal, to reach either one of two boundaries. The coin-toss square wave, which we here call periodic-persistent dichotomous noise, is a random signal that can only change its value at specified time points, where it changes its value with probability q o...

Porra? I Rovira, Josep Maria; Lindenberg, Katja

1995-01-01

324

Buying Time—The Immune System Determinants of the Incubation Period to Respiratory Viruses

Directory of Open Access Journals (Sweden)

Full Text Available Respiratory viruses cause disease in humans characterized by an abrupt onset of symptoms. Studies in humans and animal models have shown that symptoms are not immediate and appear days or even weeks after infection. Since the initial symptoms are a manifestation of virus recognition by elements of the innate immune response, early virus replication must go largely undetected. The interval between infection and the emergence of symptoms is called the incubation period and is widely used as a clinical score. While incubation periods have been described for many virus infections the underlying mechanism for this asymptomatic phase has not been comprehensively documented. Here we review studies of the interaction between human pathogenic respiratory RNA viruses and the host with a particular emphasis on the mechanisms used by viruses to inhibit immunity. We discuss the concept of the “stealth phase”, defined as the time between infection and the earliest detectable inflammatory response. We propose that the “stealth phase” phenomenon is primarily responsible for the suppression of symptoms during the incubation period and results from viral antagonism that inhibits major pathways of the innate immune system allowing an extended time of unhindered virus replication.

Thomas M. Moran

2010-11-01

325

Because there is no standard developmental staging system for the early postimplantation period of rodent embryos, investigators must now choose between a variety of systems that differ significantly. We have reviewed many of these staging systems and have summarized the ambiguities within them and the inconsistencies among them. In order to compare systems, we first obtained a consensus of the order of developmental events from the literature, and then attempted to fit existing systems into this order taking into account inconsistencies in terminology and blurred borderlines between stages. We were able to do this for most systems but not all because some were too divergent. We found that inconsistencies in definition of some terms, such as "primitive streak stage" and those used to describe the early neurulation process (neural plate, neural groove, neural folds, and head fold) cause much confusion. In order to develop an unambiguous system which can be used by all investigators, we propose to modify Theiler's system, which is one of the most commonly used systems but is not defined precisely during the early postimplantation period. We suggest making subdivisions of the original stages as follows: 1) stage 8 into 8a and 8b, by the degree of extension of the proamniotic cavity into the extraembryonic region; 2) stage 10 into 10a and 10b, by the completion of amnion formation; 3) stage 11 into 11a, 11b, and 11c, by the appearance of neural folds and foregut pocket. After Stage 12, the number of somite pairs can be used to precisely stage embryos.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1440421

Fujinaga, M; Brown, N A; Baden, J M

1992-08-01

326

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

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

327

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

328

International Nuclear Information System (INIS)

This paper is devoted to the numerical computation and continuation of families of heteroclinic connections between hyperbolic periodic orbits (POs) of a Hamiltonian system. We describe a method that requires the numerical continuation of a nonlinear system that involves the initial conditions of the two POs, the linear approximations of the corresponding manifolds and a point in a given Poincaré section where the unstable and stable manifolds match. The method is applied to compute families of heteroclinic orbits between planar Lyapunov POs around the collinear equilibrium points of the restricted three-body problem in different scenarios. In one of them, for the Sun–Jupiter mass parameter, we provide energy ranges for which the transition between different resonances is possible. (paper)

329

Stochastic resonance in a mono-stable system subject to frequency mixing periodic force and noise

International Nuclear Information System (INIS)

The phenomenon of stochastic resonance (SR) in a biased mono-stable system driven by multiplicative and additive white noise and two periodic fields is investigated. Analytic expressions of the signal-to-noise ratio (SNR) for fundamental harmonics and higher harmonics are derived by using the two-state theory. It is shown that the SNR is a non-monotonic function of the intensities of the multiplicative and additive noises, as well as the bias of the mono-stable system and SR appears at both fundamental harmonics and higher harmonics. Moreover, the higher the order of mixed harmonics is, the smaller the SNR values are, that is, the suppression exists for higher harmonics.

330

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

331

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

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

332

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. PMID:24125348

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

2013-09-01

333

BeppoSAX observations of the long period polar system V1309Ori

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

334

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

335

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

336

Evaluation of radon mitigation systems in 14 houses over a two-year period

International Nuclear Information System (INIS)

Fourteen single-family detached houses in Spokane, Washington, and Coeur D'Alene, Idaho, were monitored for two years after high concentrations of indoor radon had been mitigated. Each house was monitored quarterly using mailed alpha-track radon detectors deployed in each zone of the structure. To assess performance of mitigation systems during the second heating season after mitigation, radon concentrations in seven houses were monitored continuously for several weeks, mitigation systems in all houses were inspected, and selected other measurements were taken. In addition, occupants were also interviewed regarding their maintenance, operation, and subjective evaluation of the radon mitigation systems. Quarterly alpha-track measurements showed that radon levels had increased in most of the homes during many follow-up measurement periods when compared with concentrations measured immediately after mitigation. Mitigation-system performance was adversely affected by (1) accumulated outdoor debris blocking the outlets of subsurface pressurization pipes; (2) fans being turned off (e.g., because of excessive noise or vibration); (3) air-to-air heat exchanger, basement pressurization, and subsurface ventilation fans being turned off and fan speeds reduced; and (4) crawl-space vents being closed or sealed

337

We present period change rates (dP/dt) for 42 RR Lyrae variables in the globular cluster IC$\\,$4499. Despite clear evidence of these period increases or decreases, the observed period change rates are an order of magnitude larger than predicted from theoretical models of this cluster. We find there is a preference for increasing periods, a phenomenon observed in most RR Lyrae stars in Milky Way globular clusters. The period-change rates as a function of position in the perio...

Kunder, Andrea; Walker, Alistair; Stetson, Peter B.; Bono, Giuseppe; Nemec, James M.; Propris, Roberto; Monelli, Matteo; Cassisi, Santi; Andreuzzi, Gloria; Dall Ora, Massimo; Di Cecco, Alessandra; Zoccali, Manuela

2010-01-01

338

The present status and future plans of nuclear power plant periodic inspection system in Japan

International Nuclear Information System (INIS)

The Japanese laws stipulate that every nuclear power plant must undergo the regular inspection approximately once every year, and refueling is generally performed during the plant outage for the inspection. The regular inspection is designed so as to ensure the safe and stable operation of plants in the subsequent cycle and to minimize any effect of incidental abnormality (preventive maintenance), and to reflect the lesson learned from the incidents in nuclear power plants in Japan and abroad (corrective and recurrence preventive maintenance). Consequently, the average capacity factor of Japanese nuclear power plants has gone up to 76 % level, and the number of unexpected automatic scram during plant operation was about 0.2 per year per reactor, according to the F.Y. 1985 track record for 32 LWRs. The average outage period for regular inspection was about four months, which is longer than that in foreign countries. It is important to shorten the outage period by rationalizing regular inspection system. The measures adopted for this purpose, the Japanese laws and regulations concerning the regular inspection of nuclear power plants, the quality assurance in the regular inspection and the future rationalization are reported. (Kako, I.)

339

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

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

340

A 10-year statistics (2002-2011) of the Nordic Lightning Information System (NORDLIS) are presented. NORDLIS is a joined lightning location network between Norway, Sweden, Finland, and Estonia, comprising in 2011 of 32 lightning location sensors. Our data set contains a total of 4,121,649 cloud-to-ground (CG) flashes. We show the regional and temporal distribution of lightning in Northern Europe during the study period. Our results indicate that the average annual ground flash density values are greatest in Southern Sweden, Baltic countries and Western Finland. The average number of thunderstorm days is largest in the Baltic countries and Southwestern Sweden, and the annual number of ground flashes has varied during the study period from 250,000 to 620,000. The largest observed daily number of ground flashes is 51,500, and the largest daily ground flash density is about 5 CGs km- 2; this has occurred in southern Sweden in July 2003. The average daily number of ground flashes peaks in mid-July-early-August. Cold season (October-April) thunderstorms occur frequently over the North Sea west of Norway and in the west coast of Denmark. Our results also show that an intense thunderstorm may occur practically anywhere in the Northern Europe except for certain maritime and mountain areas.

Mäkelä, Antti; Enno, Sven-Erik; Haapalainen, Jussi

2014-03-01

341

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

342

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

343

Study on the kinetics of isothermal decomposition of selenites from IVB group of the periodic system

International Nuclear Information System (INIS)

The thermal stability and kinetics of isothermal decomposition of the selenites of germanium, tin and lead was studied. A dependence between the process activation energy and the radius and electron polarizability of the cations was observed. It was explained with the different degree of the effect of counterpolarization of the selenite anion. The negative value of the change of entropy of activation showed that the active complex is more complicated formation than the reagent. The higher absolute value of the change of entropy measured for the formation of the active complex Ge(SeO3)2 compared to that for Sn(SeO3)2 shows that the degree of rearrangement (necessary changes) of the initial crystalline structure increases with the decrease of cation radius. The isothermal decomposition of the selenites from IVB group of the periodic system was considered to be 'slow' reaction due to the significantly lower than unity values of the steric factor

344

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

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.

Mantovani, Federico; Tagliaferri, Cristian

2011-12-01

345

Optimal Backup Interval for a Database System with Full and Periodic Incremental Backup

Directory of Open Access Journals (Sweden)

Full Text Available This paper considers the following backup scheme for a database system: a database is updated at a nonhomogeneous Poisson process and an amount of updated files accumulates additively. To ensure the safety of data, full backup are performed at time NT=L or when the database fails, whichever occurs first, and between them, incremental backups are made at periodic times iT (i=1, 2, …, N-1 so as to make the backup efficiently. Using the theory of cumulative processes, the expected cost is obtained, and optimal numbers N* of incremental backup which minimizes it are analytically discussed when incremental backup interval T or full backup interval L is given. Finally, it is shown as examples that optimal numbers are numerically computed.

Cunhua Qian

2010-04-01

346

International Nuclear Information System (INIS)

Specific thermal capacity of magnesium, calcium, strontium, barium, cadmium and mercury perchlorates aqueous solutions were measured at 25 deg C and concentration interval from 0.1 to 4 mol. The apparent molal thermal capacity of the investigated perchlorates Fsub(csub(p)) and the thermal capacity change ?Csub(p) during dissolving anhydrous perchlorates in water were calculated. Specific features of interaction of cations of some Periodic System sections with water formed a basis for the discussion of the results. The conclusion is drawn that in the alkaline earth metal perchlorate solutions the sequence of ?Csub(p) values in the subgroups is determined by the competition of two factors mainly: destructurization by water ions and intensity of their interaction with coordinated water. In the zinc subgroup the polarization factor for coordinated water and the effect of extraspheric water molecules association, are more important

347

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)

348

International Nuclear Information System (INIS)

In this paper, we study the phenomenon of stochastic resonance (SR) in a periodically driven bistable system with correlations between multiplicative and additive white noise terms when there are two different kinds of time delays existed in the deterministic and fluctuating forces, respectively. Using the small time delay approximation and the theory of signal-to-noise ratio (SNR) in the adiabatic limit, the expression of SNR is obtained. The effects of the delay time ? in the deterministic force, and the delay time ? in the fluctuating force on SNR are discussed. Based on the numerical computation, it is found that: (i) There appears a reentrant transition between one peak and two peaks and then to one peak again in the curve of SNR when the value of the time delay ? is increased. (ii) SR can be realized by tuning the time delay ? or ? with fixed noise, i.e., delay-induced stochastic resonance (DSR) exists. (general)

349

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

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

350

Unitary local systems, multiplier ideals, and polynomial periodicity of Hodge numbers

The space of unitary local systems of rank one on the complement of an arbitrary divisor in a complex projective algebraic variety can be described in terms of parabolic line bundles. This space is a natural setting for studying global invariants of singularities involving multiplier ideals. We show that multiplier ideals provide natural stratifications of this space. We prove a structure theorem for these stratifications in terms of complex tori and convex rational polytopes, generalizing to the quasi-projective case results of Green-Lazarsfeld and Simpson. As an application we show the polynomial periodicity of the birational-invariant Hodge numbers of congruence covers in any dimension, generalizing results of E. Hironaka and Sakuma. We derive a geometric characterization of finite abelian covers, which recovers the ones of Namba and Pardini. We use this to do some computations which appear in their published version only in some special cases.

Budur, N

2006-01-01

351

Spin Waves in a Ferromagnetic Film with a Periodic System of Antidots

Directory of Open Access Journals (Sweden)

Full Text Available In the paper, spin waves in a thin film (composed of a uniaxial ferromagnet with a two-dimensional periodical system of antidots are studied. The film ferromagnet is considered to have the “easy axis” type. To describe such waves, the magnetostatic approximation with account for the magnetic dipole-dipole interaction, the exchange interaction and the anisotropy effects is used. For such waves, an equation for the magnetic potential is derived; for the case of remote antidots, the dispersion relation and the transverse wavenumber spectrum are found. For the case of a film thin compared to the exchange length and for the case of a film bounded by a high-conductivity metal, the longitudinal wavenumber spectrum and the frequency spectrum of such spin waves are also obtained.

V.V. Kulish

2015-03-01

352

International Nuclear Information System (INIS)

The extension of the periodic system into various new areas is investigated. Experiments for the synthesis of superheavy elements and the predictions of magic numbers are reviewed. Different ways of nuclear decay are discussed like cluster radioactivity, cold fission and cold multifragmentation, including the recent discovery of triple fission of 252 Cf. Further on, investigations on hypernuclei and the possible production of antimatter-cluster in heavy-ion collisions are reported. Various versions of the meson field theory serve as effective field theories at the basis of modern nuclear structure and suggest structure in the vacuum which might be important for the production of hyper- and antimatter. A perspective for future research is given. (author)

353

A general and efficient implementation of the coupled perturbed Hartree-Fock (CPHF) scheme in the CRYSTAL06 code that applies to systems periodic in one dimension (polymers), two dimensions (slabs), three dimensions (crystals) and, as a limiting case, zero dimension (molecules) is presented. The dielectric tensor of large unit cell systems such as boehmite (?-AlOOH, 8 atoms/cell), calcite (CaCO3, 10 atoms/cell), and pyrope (Mg3Al2Si3O12, 80 atoms/cell) has been computed. Results are well converged with respect to the computational parameters, in particular, to the number of k points in the reciprocal space and tolerances used in the truncation of the Coulomb and exchange series, showing that the same standard computational conditions used for the self-consistent-field (SCF) step can also be used safely in a CPHF calculation. Point symmetry, being so important in determining crystal properties, also reduces dramatically the computational cost both of the preliminary SCF step and the CPHF calculation, so that the dielectric tensor for large unit cell systems such as pyrope can be computed within 2 CPU hours on a single processor PC.

Ferrero, Mauro; Rérat, Michel; Orlando, Roberto; Dovesi, Roberto

2008-01-01

354

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)

355

Large-Scale, Synoptic-Period Weather Systems in Mars' Atmosphere

During late autumn through early spring, extratropical regions on Mars exhibit profound mean zonal equator-to-pole thermal contrasts associated with its waxing and waning seasonal polar ice caps. The imposition of this strong meridional temperature gradient supports intense eastward-traveling, synoptic-period weather systems (i.e., transient baroclinic/barotropic waves) within Mars' extratropical atmosphere. These disturbances grow, mature and decay within the east-west varying seasonal-mean middle and high-latitude westerly jet stream (i.e., the polar vortex) on the planet. Near the surface, such weather disturbances indicated distinctive, spiraling "comma"-shaped dust cloud structures of large scale, and scimitar-shaped dust fronts, indicative of processes associated with cyclo- and fronto-genesis. The weather systems are most intense during specific seasons on Mars, and in both hemispheres. The northern hemisphere (NH) disturbances appear to be significantly more vigorous than their counterparts in the southern hemisphere (SH). Further, the NH weather systems and accompanying frontal waves appear to have significant impacts on the transport of tracer fields (e.g., particularly dust and to some extent water species (vapor/ice) as well). Regarding dust, frontal waves appear to be key agents in the lifting, lofting, organization and transport of this atmospheric aerosol. A brief background and supporting observations of Mars' extratropical weather systems is presented. This is followed by various modeling studies (i.e., ranging from highly simplified, mechanistic and fully complex global circulation modeling investigations) that we are pursuing. In particular, transport of scalar quantities (e.g., tracers and high-order dynamically revealing diagnostic fields) are investigated. A discussion of outstanding issues and future modeling pursuits is offered related to Mars' extratropical traveling weather systems.

Hollingsworth, Jeffery L.; Kahre, M.

2013-10-01

356

International Nuclear Information System (INIS)

The article adduces results of the optimum control periodicity account for the system of the reactor emergency cooling by high pressure pumps. Authors showed the control periodicity can be increased in several times with respect to regulations control periodicity

357

Vitrification and some properties of BaO-Nb2O5-P2O5 system glasses

International Nuclear Information System (INIS)

The study of glasses in niobium-phosphate systems with elements of groups 1 and 2 of the Mendeleev Periodic System is continued in the given work. The system BaO-Nb2O5-P2O5 is of interest from the viewpoint of creaction on its basis of phosphate flintglasses with a high refractive index, peculiar course of relative particular dispersion in the blue (g-F') part of spectrum and low density. In system BaO-Nb2O5-P2O5 vitrification region is ascertained and range of colourless glasses is isolated, which is restricted by the content of 25-30 mol.% Nb2O5. Compositions of glasses possessing the minimum tendency to crystallization are found. It is shown that with Nb2O5 content increase the refractive index, average dispersion and density increase. It is ascertained that glasses in the system studied possess peculiar course of relative particular dispersion in the range of spectrum (g-F'). The value ?b is shifted to the short-wave range of spectrum as compared with fluorotitanium and lead-silicated flintglasses

358

A magnetic reconnection model for quasi-periodic oscillations in black hole systems

The quasi-periodic oscillations (QPOs) in black hole (BH) systems of different scales are interpreted based on the magnetic reconnection of the large-scale magnetic fields generated by the toroidal electric currents flowing in the inner region of accretion disk, where the current density is assumed to be proportional to the mass density of the accreting plasma. The magnetic connection (MC) is taken into account in resolving the dynamic equations of the accretion disk, in which the MC between the inner and outer disk regions, the MC between the plunging region and the disk, and the MC between the BH horizon and the disk are involved. It turns out that the single QPO frequency of several BH systems of different scales can be fitted by invoking the magnetic reconnection due to the MC between the inner and outer regions of the disk, where the BH binaries XTE J1859+226, XTE J1650-500 and GRS 1915+105 and the massive BHs in NGC 5408 X-1 and RE J1034+396 are included. In addition, the X-ray spectra corresponding to ...

Huang, Chang-Yin; Wang, Jiu-Zhou; Wang, Zhi-Yun

2013-01-01

359

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

360

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

361

Theory and Applications of the Systematic Detection of Unstable Periodic Orbits in Dynamical Systems

A topological approach and understanding to the detection of unstable periodic orbits based on a recently proposed method (PRL 78, 4733 (1997)) is developed. This approach provides a classification of the set of transformations necessary for the finding of the orbits. Applications to the Ikeda and Henon map are performed, allowing a study of the distributions of Lyapunov exponents for high periods. Particularly the properties of the least unstable orbits up to period 36 are ...

Pingel, Detlef; Schmelcher, Peter; Diakonos, Fotis; Biham, Ofer

2000-01-01

362

Finite-time synchronization of drive-response systems via periodically intermittent adaptive control

In this paper, the finite-time synchronization between two complex dynamical networks via the periodically intermittent adaptive control and periodically intermittent feedback control is studied. The finite-time synchronization criteria are derived based on finite-time stability theory, the differential inequality and the analysis technique. Since the traditional synchronization criteria for some models are improved in the convergence time by using the novel periodically interm...

Mei, Jun; Jiang, Minghui; Wang, Xiaohong; Han, Jiali; Wang, Shuangtao

2014-01-01

363

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

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

364

On the periodic dependence of baric coefficient of melting-point curves of simple substances

International Nuclear Information System (INIS)

The values of the baric coefficient for simple substances have been refined on the basis of the Mendeleev's Periodic Law by two methods: plotting the correlative dependences of dT/dP on the conditional atomic volume; plotting the rigid schemes of relationships between dT/dP and atomic volume and by characteristics of the strength of an interatomic bond. The baric coefficient of the melting curves of simple bodies reflects a change in the character and strength of interatomic bonds upon transition from a solid state into liquid. This underlines the meaning of the baric coefficient as not only the characteristics of the phase transition nature but as an important property reflecting the character of electron melts

365

On a possible linkage between W-type WUMa systems and the short period RSCVn-like binaries

International Nuclear Information System (INIS)

The authors analyze the general properties of a group of WUMa-type binaries, which show RSCVn-like activity. The position of these stars in the colour-density and mass-orbital momentum diagrams is studied, but no definite answer can be given on the linkage between short period RSCVn systems (SPG) and WUMa systems with RSCVn-like activity (WWG). (Auth.)

366

Review of nuclear air treatment system related License Event Reports for the period 1985 - 1987

International Nuclear Information System (INIS)

This paper will continue the review of HVAC/NATS related LERS presented at past Air Cleaning Conferences by Dr. D. W. Moeller and his associates. The general approach and format are similar. LER abstracts from mid 1985 through 1987 were reviewed and those related to HVAC/NATS classified and analyzed. The categories were jointly developed by Dr. Moeller, Dr. Casper Sun and myself. In appropriate cases both primary and secondary categories fora problem are given. A basic listing by category and brief statistical review are presented. Additionally a number of categories are discussed in some detail. The categories chosen for specific review are intended to highlight particular problem areas. NUREG/CR-2000 License Event Report (LER) Compilation is the basis for the initial review and coding. In essentially all cases where an LER is classified as of interest the complete LER was obtained and reviewed in full. The intent of this paper is to provide a basis for the industry to document and analyze problem areas that require additional attention. It appears that about 15% of all LERS in the subject period are HVAC/NATS related. This figure is generally consistent with those reported at the 17th DOE Nuclear Air Cleaning Conference. It is hoped that such attention will allow additional resources to be allocated to upgrade systems, procedures and training as well as in some cases government regulation

367

Study on the kinetics of isothermal decomposition of selenites from IVB group of the periodic system

Energy Technology Data Exchange (ETDEWEB)

The thermal stability and kinetics of isothermal decomposition of the selenites of germanium, tin and lead was studied. A dependence between the process activation energy and the radius and electron polarizability of the cations was observed. It was explained with the different degree of the effect of counterpolarization of the selenite anion. The negative value of the change of entropy of activation showed that the active complex is more complicated formation than the reagent. The higher absolute value of the change of entropy measured for the formation of the active complex Ge(SeO{sub 3}){sub 2} compared to that for Sn(SeO{sub 3}){sub 2} shows that the degree of rearrangement (necessary changes) of the initial crystalline structure increases with the decrease of cation radius. The isothermal decomposition of the selenites from IVB group of the periodic system was considered to be 'slow' reaction due to the significantly lower than unity values of the steric factor.

Vlaev, L.T.; Gospodinov, G.G.; Genieva, S.D

2004-07-09

368

A Periodical Production Plan for Uncertain Orders in a Closed-Loop Supply Chain System

Directory of Open Access Journals (Sweden)

Full Text Available Production planning is a major activity in the manufacturing or processing industries. A good plan helps the company lower its expenses, increase profit, or both. However, the worldwide economy is made up of closely related systems. Thus, a small change induces fluctuation in the supply chain. Although a production plan is based on the predicted demand, economic fluctuations make prediction difficult. Therefore, coping with production risksof uncertain demands heavily depends on the judgment and experience of the producer or customer. In addition, the reuse of recyclable products has become a major approach in reducing resource consumption because of environmental consciousness. Thus, a closed-loop supply chain has replaced the traditional supply chain to facilitate recycling, accommodate reprocess, ease environmental degradation, and save on resource costs. This study thus considers a production plan in a closed-loop supply chain, where periodic orders of retailers are adjusted and described byfuzzy quantities. The goal of the producer is to maximize profit while trying to satisfy these orders to the greatest extent. Fuzzy Set Theory is applied to construct a Fuzzy Chance-Constrained Production Mix Model (FCCPMM to enable the risk attitude of the decision maker to be adopted to address uncertainty.Theoretical evidence is supported by numerical illustration

Hsiao-Fan Wang

2014-12-01

369

Exact solution for quantum dynamics of a periodically-driven two-level-system

We present a family of exact analytic solutions for non-linear quantum dynamics of a two-level system (TLS) subject to a periodic-in-time external field. In constructing the exactly solvable models, we use a "reverse engineering" approach where the form of external perturbation is chosen to preserve an integrability constraint, which yields a single non-linear differential equation for the ac-field. A solution to this equation is expressed in terms of Jacobi elliptic functions with three independent parameters that allows one to choose the frequency, average value, and amplitude of the time-dependent field at will. This form of the ac-drive is especially relevant to the problem of dynamics of TLS charge defects that cause dielectric losses in superconducting qubits. We apply our exact results to analyze non-linear dielectric response of such TLSs and show that the position of the resonance peak in the spectrum of the relevant correlation function is determined by the quantum-mechanical phase accumulated by th...

Gangopadhyay, Anirban; Galitski, Victor

2010-01-01

370

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

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

371

Application of transfer matrices to surface states in finite periodic systems of quantum wells

For a system of N coupled quantum wells an exact energy-dispersion relation in terms of composite functions was derived by Liboff and Seidman 1 (1990). The essential qualitative feature of this equation was the emergence of a band structure for only a few quantum wells. Therefore one can consider this an embryonic band structure of any lattice with short range peridocity. Using transfer matrices one can find a parallel result for the wave function, that is, an exact closed form solution with N as an explicit variable. Based on a result of Abeles2 (1950), the transfer matrix for N arbitrary barriers can be expressed in terms of the transfer matrix of a single barrier multiplied by Chebyshev polynomials of degree N - 1 and N - 2. This expression for the wavefunction allows one to write an exact energy-dispersion relation for a finite-periodic system of N-coupled quantum wells for a general barrier shape. Once the transfer matrix for this barrier is determined, an exact algebraic expression can be written, the roots of which are the eigenenergies. This result represents a generalization of the expression in Liboff & Seidman (1990) since there the expression was specifically for rectangular quantum wells whereas this expression will work for any particular quantum well so long as the transfer matrix across the barrier separating the wells is known. From the eigenergies, the wavefunctions can then be written in terms of the recursive expression for the transfer matrix to determine if there are surface states (or surface resonances). A comparison of this methodology is made to that of Tamm's direct matching procedure for a semi-infinite lattice. 1R. L. Liboff & S. R. Seidman, "Exact energy-dispersion relations for N-well superlattice configurations," Phys Rev B, vol. 42, 1990, p. 9552. 2F. Abeles, "Reserches sur la propagation des onde electromagnetiques sinusoidales dans les milieux stratifies", Ann. Phys. Paris, vol. 5, 1950 p. 706.

Seidman, Steven Russell

372

International Nuclear Information System (INIS)

Control systems in safety-critical applications often consist of two categories: on-line systems and standby systems. When the on-line systems fail to operate properly, the standby systems should automatically take actions to prevent any catastrophic consequences. However, the standby systems might fail as well. Therefore, regular test and maintenance need to be performed to reveal hidden failures. The objective of this paper is to investigate and compare there test and maintenance strategies for a standby k-out-of-n safety-critical system. The three strategies are periodic test, periodic preventive maintenance and periodic predictive maintenance and they are all performed on-line. Each channel of the k-out-of-n system adopts an age-dependent reliability model. Based on this model, the system unavailability, the probability of spurious operation and the overall cost are investigated, with consideration of the three test and maintenance strategies. One of the main standby safety systems in Canadian Deuterium-Uranium (CANDU) based Nuclear Power Plants (NPPs), the Shutdown System Number One (SDS1), is used as an example to illustrate the proposed analysis. (authors)

373

Directory of Open Access Journals (Sweden)

Full Text Available Parametric study is carried out in the present article to investigate the unsteady performance of solar energy gain and heat retention of two different integrated-collector-storage systems. The systems are the conventional rectangular-shaped storage tank and the modified tank shaped as rectangular cuboid with one semi -circular top. The two systems have the same absorber surface area and volume for water. The heat and fluid flow is assumed to be unsteady, two-dimensional, laminar and incompressible. The performances of the two systems are evaluated based on the maximum temperature in the system during daytime heating period and nighttime cooling period. For comprehensive study, 24 hours simulations for 3 cases with different wall boundary condition impose on the absorber plate are investigated. The simulation results show that the modified system has better heat retain than the conventional system. Periodic variations of both systems are investigated, and it is found that both systems show consistent results on different days. The modified system is able to store most of the thermal energy in the semi-circular top region with higher temperature than that of the conventional system.

Nawaf H. Saeid

2010-10-01

374

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 min is found for the faint magnetic system SDSS J132411.57+032050.4, whose orbital light variations are reminiscent of AM Her. Improved orbital period measurements are also given for three known SDSS cataclysmic variables. We investigate the orbital period distribution and fraction of eclipsing systems within the SDSS sample and for all cataclysmic variables with a known orbital period, with the finding that the fraction of known CVs which are eclipsing is not strongly dependent on the orbital period. The reduced observational data presented in this work are 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/573/A61 and at http://www.astro.keele.ac.uk/~jkt/

Southworth, J.; Tappert, C.; Gänsicke, B. T.; Copperwheat, C. M.

2015-01-01

375

We analyze the transition from periodic solutions to spatiotemporal chaos in a system of four globally coupled Ginzburg Landau equations describing the dynamics of instabilities in the electroconvection of nematic liquid crystals, in the weakly nonlinear regime. If spatial variations are ignored, these equations reduce to the normal form for a Hopf bifurcation with O(2) x O(2) symmetry. Coexistence of low dimensional and extensive spatiotemporal chaotic patterns, as well as a temporal period doubling route to spatiotemporal chaos, corresponding to a period doubling cascade towards a chaotic attractor in the normal form, are also identified and discussed, for values of the parameters including experimentally measured values of the nematic I52.

Oprea, Iuliana; Dangelmayr, Gerhard

2008-03-01

376

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

377

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

378

Cogging effect which can be treated as a type of position-dependent periodic disturbance, is a serious disadvantage of the permanent magnetic synchronous motor (PMSM). In this paper, based on a simulation system model of PMSM position servo control, the cogging force, viscous friction, and applied load in the real PMSM control system are considered and presented. A dual high-order periodic adaptive learning compensation (DHO-PALC) method is proposed to minimize the cogging effect on the PMSM position and velocity servo system. In this DHO-PALC scheme, more than one previous periods stored information of both the composite tracking error and the estimate of the cogging force is used for the control law updating. Asymptotical stability proof with the proposed DHO-PALC scheme is presented. Simulation is implemented on the PMSM servo system model to illustrate the proposed method. When the constant speed reference is applied, the DHO-PALC can achieve a faster learning convergence speed than the first-order periodic adaptive learning compensation (FO-PALC). Moreover, when the designed reference signal changes periodically, the proposed DHO-PALC can obtain not only faster convergence speed, but also much smaller final error bound than the FO-PALC. PMID:20605022

Luo, Ying; Chen, Yangquan; Pi, Youguo

2010-10-01

379

Complex dynamics and switching transients in periodically forced Filippov prey–predator system

International Nuclear Information System (INIS)

Highlights: •We develop a Filippov prey–predator model with periodic forcing. •The sliding mode dynamics and its domain have been investigated. •The existence and stability of sliding periodic solution have been discussed. •The complex dynamics are addressed through bifurcation analyses. •Switching transients and their biological implications have been discussed. - Abstract: By employing threshold policy control (TPC) in combination with the definition of integrated pest management (IPM), a Filippov prey–predator model with periodic forcing has been proposed and studied, and the periodic forcing is affected by assuming a periodic variation in the intrinsic growth rate of the prey. This study aims to address how the periodic forcing and TPC affect the pest control. To do this, the sliding mode dynamics and sliding mode domain have been addressed firstly by using Utkin’s equivalent control method, and then the existence and stability of sliding periodic solution are investigated. Furthermore, the complex dynamics including multiple attractors coexistence, period adding sequences and chaotic solutions with respect to bifurcation parameters of forcing amplitude and economic threshold (ET) have been investigated numerically in more detail. Finally the switching transients associated with pest outbreaks and their biological implications have been discussed. Our results indicate that the sliding periodic solution could be globally stable, and consequently the prey or pest population can be controlled such that its density falls below the economic injury level (EIL). Moreover, the switching transients have both advantages and disadvantages concerning pest control, and the magnitude and frequency of switching transients depend on the initial values of both populations, forcing amplitude and ET

380

Transient flow analysis in reactor coolant pump systems during flow coastdown period

International Nuclear Information System (INIS)

The rapid flow transient calculation in reactor coolant pump system is important in the safety analysis of a nuclear reactor. An accurate transient analysis of flow coastdown is also important and necessary for the design and manufacture of a reactor coolant pump. Only under the reliable work of a reactor coolant pump the safety of a nuclear power plant can be guaranteed. A mathematical model is developed for solving flow rate transient and pump speed transient during flow coastdown period. The detailed information of the centrifugal pump characteristics is not required. The flow rate and pump speed are solved analytically. The analytic solution of non-dimensional flow rate indicates that non-dimensional flow rate is determined by energy ratio ?. The kinetic energy of the loop coolant fluid and the kinetic energy stored in the rotating parts are two important parameters in form of ?. When the steady-state flow rate and pump speed are constant, the inertia of primary loop fluid and the pump moment of inertia are also two important parameters in flow transient analysis. For the condition all pump shafts are seized, the flow decay depends on the inertia of primary loop fluid. For the case that pump inertia is very large, the flow decay is determined by the pump inertia. The calculated non-dimensional flow rate and non-dimensional pump speed using the model are compared with published experimental data of two nuclear power plants and a reactor model test on flow coastdoand a reactor model test on flow coastdown transients. The comparison results show a good agreement. As the flow rate approaches to zero, the increase difference between experimental and calculated value is due to the effect of the mechanical friction loss.

381

Chemiluminescence determination of mezlocillin by the luminol-potassium periodate system

Scientific Electronic Library Online (English)

Full Text Available 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

382

Transient flow analysis in reactor coolant pump systems during flow coastdown period

Energy Technology Data Exchange (ETDEWEB)

The rapid flow transient calculation in reactor coolant pump system is important in the safety analysis of a nuclear reactor. An accurate transient analysis of flow coastdown is also important and necessary for the design and manufacture of a reactor coolant pump. Only under the reliable work of a reactor coolant pump the safety of a nuclear power plant can be guaranteed. A mathematical model is developed for solving flow rate transient and pump speed transient during flow coastdown period. The detailed information of the centrifugal pump characteristics is not required. The flow rate and pump speed are solved analytically. The analytic solution of non-dimensional flow rate indicates that non-dimensional flow rate is determined by energy ratio {beta}. The kinetic energy of the loop coolant fluid and the kinetic energy stored in the rotating parts are two important parameters in form of {beta}. When the steady-state flow rate and pump speed are constant, the inertia of primary loop fluid and the pump moment of inertia are also two important parameters in flow transient analysis. For the condition all pump shafts are seized, the flow decay depends on the inertia of primary loop fluid. For the case that pump inertia is very large, the flow decay is determined by the pump inertia. The calculated non-dimensional flow rate and non-dimensional pump speed using the model are compared with published experimental data of two nuclear power plants and a reactor model test on flow coastdown transients. The comparison results show a good agreement. As the flow rate approaches to zero, the increase difference between experimental and calculated value is due to the effect of the mechanical friction loss.

Gao Hong, E-mail: hgao@sjtu.edu.c [Institute of Design and Control Engineering for Heavy Equipment, State Key Laboratory of Mechanical System and Vibration, School of Mechanical Engineering, Shanghai Jiao Tong University, No. 800 Dong Chuan Road, Shanghai 200240 (China); Gao Feng; Zhao Xianchao; Chen Jie; Cao Xuewu [Institute of Design and Control Engineering for Heavy Equipment, State Key Laboratory of Mechanical System and Vibration, School of Mechanical Engineering, Shanghai Jiao Tong University, No. 800 Dong Chuan Road, Shanghai 200240 (China)

2011-02-15

383

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

384

International Nuclear Information System (INIS)

Functionally the engineered safety system (ESS) can be devided into two main parts: the emergency core cooling system and the pressure reduction system of hermetic rooms. Both parts consist of passive and active subsystems, their availability has periodically to be checked during the normal operation of the nuclear power plant. The passive sub-systems are checked during the annual shutdown period of the reactors when their reloading having been finished, the active subsystems may and have to be checked during the normal operation of the plant, too. This can be performed by the appropriate execution of the operating start-up instructions concerning these systems, while the effectiveness of their checking can be increased by computerized data processing. A simple method resulting satisfactory information for the operator to qualify the ESS is presented. (orig./HP)

385

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

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 struc...

Romero-garci?a, V.; Sa?nchez-pe?rez, J. V.; Garcia-raffi, L. M.

2011-01-01

386

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

387

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)

388

A class of differential equations with pure delay and a hyperbolic nonlinearity, analogous to the Michaelis-Menten term in chemical reaction kinetics, is examined. Conditions for the existence of periodic solutions are established. The amplitude and period dependences on the equation parameters are estimated analytically. A mixed analytico-numerical approach is used in the computations, because a straightforward integration of the equations is numerically ill conditioned. (11 refs).

Gumowski, I

1977-01-01

389

Directory of Open Access Journals (Sweden)

Full Text Available Led-if this work aimed to evaluate the effect of Indian summer periods about the productivity of corn for silage grown in no-tillage and conventional systems.The experiment was conducted in split plots, distributed in randomized block design, and systems were evaluated plots of no-till and conventional tillage and subplots, six periods of dry spells (2, 6, 10, 14, 18 and 22 days applied from the 34 days after planting, respectively.The crop was irrigated by drip, with individual control of the water supply in each sub-plot, for interruption of the water supply during periods of Indian summer, as well as the irrigation management outside the periods of Indian summer, which was carried out separately for each sub-plot, based on soil water tension, in order to allow for the measurement of water consumption in the cycle of culture.It was found that Indian summer periods of 6, 10, 14, 18 and 22 days reduced dry matter productivity of corn for silage in 8.74; 26.47; 42.5; 48.05 and 64.60% of no-till and in 16.42; 32.04; 47.38; 65.23 and 74.19% in conventional tillage, respectively. The no-tillige system reduced consumption and improved water use efficiency in the production of corn for silage, reduced losses caused by water deficit.

Francineudo Alves Silva

2015-02-01

390

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

391

DEFF Research Database (Denmark)

We extend well-known formulae for the optimal base stock of the inventory system with continuous review and constant lead time to the case with periodic review and stochastic, sequential lead times. Our extension uses the notion of the ‘extended lead time’. The derived performance measures are exact for Poisson demands.

Johansen, SØren Glud; Thorstenson, Anders

2008-01-01

392

DEFF Research Database (Denmark)

We show that well-known textbook formulae for determining the optimal base stock of the inventory system with continuous review and constant lead time can easily be extended to the case with periodic review and stochastic, sequential lead times. The provided performance measures and conditions for optimality are exact.

Johansen, SØren Glud; Thorstenson, Anders

2006-01-01

393

DEFF Research Database (Denmark)

We extend well-known formulae for the optimal base stock of the inventory system with continuous review and constant lead time to the case with periodic review and stochastic, sequential lead times. Our extension uses the notion of the 'extended lead time'. The derived performance measures are exact for Poisson demands.

Johansen, SØren Glud; Thorstenson, Anders

2008-01-01

394

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

395

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

396

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

397

International Nuclear Information System (INIS)

The paper specifies historiography of creation initial period of Soviet System of the Long Range Detection on the basis of newly discovered archival materials and the new approaches to the known facts and documents, mainly, from the comparison of the Long Range Detection history in USA and USSR. (author)

398

International Nuclear Information System (INIS)

The phenomenon of stochastic resonance (SR) in an asymmetric mono-stable system subject to two external periodic forces and multiplicative and additive noise is investigated. It is shown that the signal-to-noise ratio (SNR) for the fundamental and higher harmonics is a non-monotonic function of the intensities of the multiplicative and additive noise, as well as of the system parameter. Moreover, the SNR for the fundamental harmonic decreases with the increase of the system asymmetry, while the SNR for the higher harmonics behaves non-monotonically as the system asymmetry varies.

399

Weak interactions in Graphane/BN systems under static electric fields-A periodic ab-initio study.

Ab-initio calculations via periodic Hartree-Fock (HF) and local second-order Møller-Plesset perturbation theory (LMP2) are used to investigate the adsorption properties of combined Graphane/boron nitride systems and their response to static electric fields. It is shown how the latter can be used to alter both structural as well as electronic properties of these systems. PMID:25903899

Steinkasserer, Lukas Eugen Marsoner; Gaston, Nicola; Paulus, Beate

2015-04-21

400

In forward flight, helicopter rotor blades function within a highly complex aerodynamic environment that includes both near-blade and far-blade aerodynamic phenomena. These aerodynamic phenomena cause fluctuating aerodynamic loads on the rotor blades. These loads when coupled with the dynamic characteristics and elastic motion of the blade create excessive amount of vibration. These vibrations degrade helicopter performance, passenger comfort and contributes to high cost maintenance problems. In an effort to suppress helicopter vibration, recent studies have developed active control strategies using active pitch links, flaps, twist actuation and higher harmonic control of the swash plate. In active helicopter vibration control, designing a controller in a computationally efficient way requires accurate reduced-order models of complex helicopter aeroelasticity. In previous studies, controllers were designed using aeroelastic models that were obtained by coupling independently reduced aerodynamic and structural dynamic models. Unfortunately, these controllers could not satisfy stability and performance criteria when implemented in high-fidelity computer simulations or real-time experiments. In this thesis, we present a novel approach that provides accurate time-periodic reduced-order models and time-periodic H2 and H infinity controllers that satisfy the stability and performance criteria. Computational efficiency and the necessity of using the approach were validated by implementing an actively controlled flap strategy. In this proposed approach, the reduced-order models were directly identified from high-fidelity coupled aeroelastic analysis by using the time-periodic subspace identification method. Time-periodic H2 and Hinfinity controllers that update the control actuation at every time step were designed. The control synthesis problem was solved using Linear Matrix Inequality and periodic Riccati Equation based formulations, for which an in-house periodic Riccati solver was developed. The results show that first, important helicopter aeroelastic features can only be captured using high-fidelity coupled aeroelastic analysis; ignoring these features through uncoupled analysis leads to closed-loop performance degradation and instabilities. Second, time-periodic models are necessary to obtain an accurate map between control actuation and helicopter aeroelastic response; time-invariant models fail to provide accurate prediction. Third, time-Periodic H2 and H infinity controllers satisfy the stability and design performance criteria when implemented in high-fidelity aeroelastic analysis. Finally, we propose robust H2 and Hinfinity controller design strategies that are capable of modeling variable advance ratios.

Ulker, Fatma Demet

401

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

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

402

Survival probability and saturation energy in periodically driven quantum chaotic systems

International Nuclear Information System (INIS)

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.

403

EDF-schedulability of synchronous periodic task systems is coNP-hard

In the synchronous periodic task model, a set \\tau_1,...,\\tau_n of tasks is given, each releasing jobs of running time c_i with relative deadline d_i, at each integer multiple of the period p_i. It is a classical result that Earliest Deadline First (EDF) is an optimal preemptive uni-processor scheduling policy. For constrained deadlines, i.e. d_i = 0: \\sum_{i=1}^n (floor(Q-d_i)/p_i) + 1) * c_i

Eisenbrand, Friedrich; Rothvoß, Thomas

2010-01-01

404

Continuing our work from Paper I (Southworth et al., 2006) we present medium-resolution spectroscopy and broad-band photometry of seven cataclysmic variables (CVs) discovered by the SDSS. For six of these objects we derive accurate orbital periods, all which are measured for the first time. For SDSS J013132.39+090122.2, which contains a non-radially pulsating white dwarf, we find an orbital period of 81.54 +/- 0.13 min and a low radial velocity variation amplitude indicative of an extreme mass ratio. For SDSS J205914.87+061220.4, we find a period of 107.52 +/- 0.14 min. This object is a dwarf nova and was fading from its first recorded outburst throughout our observations. INT photometry of SDSS J155531.99-001055.0 shows that this system undergoes total eclipses which are 1.5 mag deep and occur on a period of 113.54 +/- 0.03 min. A NOT light curve of SDSS J075443.01+500729.2 shows that this system is also eclipsing, on a period of 205.965 +/- 0.014 min, but here the eclipses are V-shaped and only 0.5 mag deep...

Southworth, John; Gänsicke, B T; Aungwerojwit, A; Hakala, P; De Martino, D; Lehto, H

2007-01-01

405

International Nuclear Information System (INIS)

In the first chapter, the eigenvalue problem for a periodic Schroedinger operator, Lf = (-d2/dx2 + v)f = Ef, is viewed as a two-dimensional Hamiltonian system which is integrable in the sense of Arnold and Liouville. With the aid of the Floquet-BLoch theory, it is shown that such a system is conjugate to two harmonic oscillators with frequencies ? and omega, being the rotation number for L and 2?/omega the period of the potential v. This picture is generalized in the second chapter, to quasi periodic Schroedinger operators, L/sub epsilon/, with highly irrational frequencies (omega1, ..., omega/sub d/), which are a small perturbation of periodic operators. In the last chapter, the absolutely continuous spectrum ?/sub ac/ of a general quasi-periodic Schroedinger operators is considered. The Radon-Nikodym derivatives (with respect to Lebesgue measure) of the spectral measures are computed in terms of special independent eigensolutions existing for almost ever E in ?/sub ac/. Finally, it is shown that weak Bloch waves always exist for almost ever E in ?/sub ac/ and the question of the existence of genuine Bloch waves is turned into a regularity problem for a certain nonlinear partial differential equation on a d-dimensional torus

406

Discovery of the 1.80 hr Spin Period of the White Dwarf of the Symbiotic System BF Cyg

We report on the discovery of a coherent periodicity in the B light curve of the symbiotic star BF Cyg. The signal was detected in some sections of the light curve of the star recorded in the year 2003 as double hump periodic variations with an amplitude of ~7 mmag. In the year 2004 the signal was also present in only a subsection of the light curve. In that year, the system was about twice as bright and the amplitude of the oscillations was about half of what it was in 2003. In 2004 the cycle structure was of a single hump, the phase of which coincided with the phase of one of the humps in the 2003 cycle. No periodic signal was detected in a third, short series of observations performed in the year 2007, when the star was three magnitudes brighter than in 2003. We interpret the periodicity as the spin period of the white dwarf component of this interacting binary system. We suggest that the signal in 2003 originated in two hot spots on or near the surface of the white dwarf, most likely around the two antipo...

Formiggini, Liliana

2009-01-01

407

Generalized synchronization in the action of a chaotic signal on a periodic system

Generalized synchronization is observed during the action of a chaotic signal on generators of periodic oscillations. The features in the behavior of the synchronous regime threshold upon a change in the chaotic signal parameters are investigated. The possibility of using such devices for concealed information transfer is demonstrated.

Koronovskii, A. A.; Moskalenko, O. I.; Pavlov, A. S.; Frolov, N. S.; Hramov, A. E.

2014-05-01

408

International Nuclear Information System (INIS)

To decrease the timescale for the installation of a nuclear reactor, a reduced-scale model system is proposed for Korea's third generation nuclear reactor, the APR1400 (advanced power reactor 1400). The construction period of a nuclear power plant is one of the most important factors to make a company competitive in international nuclear energy markets. Our study is related to the modularization of reactor internals to reduce the construction period of nuclear power plants. Generally, reactor internals comprise three components: the core support barrel (CSB), the lower support structure (LSS)/core shroud (CS), and the upper guide structure (UGS). The existing method of assembly is very complicated and requires approximately 8-10 months to complete. The installation of the reactor vessel (RV) is a critical process during the construction period. The proposed method for the modularization of reactor internals can shorten the construction period by a minimum of 2 months compared to the existing method. In order to modularize the reactor internals, gaps between the CSB snubber lug and RV core-stabilizing lug must be measured using a remote method from outside the RV. Therefore, the development of a remote measurement system was necessary. In this paper, we select a suitable sensor and develop a reduced-scale model system for the physical simulation of gap measurement

409

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

410

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 sys, 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

411

Front bifurcation in a tristable reaction-diffusion system under periodic forcing.

A piecewise linear tristable reaction-diffusion equation under external forcing of periodic type is considered. A special feature of the forcing is that the force moves together with the traveling wave. Front velocity equations are obtained analytically using matching procedures for the front solutions. It is noted that there is a restriction in building of null-cline. For each choice of outer branches of null-cline the middle interfacial zone should not exceed some critical value. When this zone is larger the front does not exist. It is found that in the presence of forcing there exists a set of front solutions with different phases (matching point coordinates). The periodic forcing produces a change in the velocity-versus-phase diagram. For a specific choice of wave number, there is a bubble formation which corresponds to additional solutions when the velocity bifurcates to form three fronts. PMID:15089393

Zemskov, E P

2004-03-01

412

Amplification Effects on the Transmission and Reflexion Phases in 1D Periodic Systems

We investigate the localization observed recently for locally non-hermitian Hamiltonians by studying the effect of the amplification on the scaling behavior of the transmission and reflection phases in 1D periodic chains of $\\delta$-potentials. The amplification here is represented by an imaginary term added to the on-site potential. It is found that both phases of the transmission and reflection amplitudes are strongly affected by the amplification term. In particular, the ...

Zekri, N.; Bennabi, K.; Maarouf, S.

1999-01-01

413

Operator support systems in NPPs. Summary of the activities in the period 1993-1995

International Nuclear Information System (INIS)

The report presents an overview of major activities performed in ENEA and ANPA in the period 1993-1995 related to CRP subject. Being in Italy the Nuclear Power Plant not in operation since 1987, studied and research under development related to the CRP subject make reference to technological themes such as the methods to improve the software quality in critical application and the methods to improve the operator training. (author). 5 refs

414

On the Special Role of Symmetric Periodic Orbits in a Chaotic System

After early work of Henon it has become folk knowledge that symmetric periodic orbits are of particular importance. We reinforce this belief by additional studies and we further find that invariant closed symplectic submanifolds caused by discrete symmetries prove to be an important complement to the long known role of the orbits. The latter have particular importance in semi-classics. Based on the structural stability of hyperbolic horseshoes we give an argument that opens an avenue to the understanding of these facts.

Bénet, L; Papenbrock, T; Seligman, T H

1998-01-01

415

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

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

416

OBSERVATION OF PERIODIC AND CHAOTIC INSTABILITIES IN AN ALL OPTICAL BISTABLE SYSTEM

Bifurcations to periodic and chaotic states have been observed in an all optical ring cavity. A mode-locked pulse train was used as a strong quasi-C.W. light source. The ring cavity consisted of a single-mode optical fiber allowing a propagation of a quasi-plane wave. The results are in good agreement with the theory of Ikeda et al.

Nakatsuka, H.; Asaka, S.; Ito, H.; Matsuoka, M.

1983-01-01

417

First-order Phase Transitions in Finite Systems I: Periodic Boundary Conditions

Directory of Open Access Journals (Sweden)

Full Text Available We briefly review rigorous results on the finite-size effect near first-order phase transitions at which a two-phase coexistence takes place. We consider a large class of statistical mechanical models in (hypercubic volumes with periodic boundary conditions at low temperatures. The results show a universal behavior of the asymptotic smoothing of the phase transition discontinuities. The determination of the transition point from

Igor Medved

2005-01-01

418

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

419

Buying Time—The Immune System Determinants of the Incubation Period to Respiratory Viruses

Respiratory viruses cause disease in humans characterized by an abrupt onset of symptoms. Studies in humans and animal models have shown that symptoms are not immediate and appear days or even weeks after infection. Since the initial symptoms are a manifestation of virus recognition by elements of the innate immune response, early virus replication must go largely undetected. The interval between infection and the emergence of symptoms is called the incubation period and is widely used as a c...

Moran, Thomas M.; Tamar Hermesh; Bruno Moltedo; Lo?pez, Carolina B.

2010-01-01

420

...Commission [Docket No. ER11-2256-000] California Independent System Operator Corporation; Notice Establishing Comment...2011, to discuss issues related to California Independent System Operator Corporation's (CAISO) Capacity...

2011-05-09

421

77 FR 8250 - California Independent System Operator Corporation; Notice Establishing Comment Periods

...Commission [Docket No. ER11-4580-000] California Independent System Operator Corporation; Notice Establishing Comment...conference to discuss issues related to the California Independent System Operator Corporation's proposal to...

2012-02-14

422

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 ...

Santhi Baskaran; Thambidurai, P.

2010-01-01

423

Stabilizing periodic orbits of chaotic systems using fuzzy control of Poincare map

International Nuclear Information System (INIS)

In this paper a fuzzy control algorithm is used to stabilize the fixed points of a chaotic system. No knowledge of the dynamic equations of the system is needed in this approach and the whole system is considered as a black box. Two main approaches have been investigated: fuzzy clustering and table look up methods. As illustrative examples these methods have been applied to Bonhoeffer van der Pol oscillator and the Henon chaotic system and the convergence toward fixed points is observed

424

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

425

Quasi-Periodic Post-Critical Response Types of a Harmonically Excited Auto-Parametric System.

Czech Academy of Sciences Publication Activity Database

Kippen : Civil-Comp Press , 2011 - (B.H.V. Topping; Y. Tsompanakis), s. 1-26 ISBN 978-1-905088-46-1. ISSN 1759-3433. [International Conference on Civil, Structural and Environmental Engineering Computing /13./. Chania (GR), 06.09.2011-09.09.2011] R&D Projects: GA AV ?R(CZ) IAA200710805; GA ?R(CZ) GA103/09/0094; GA AV ?R(CZ) IAA200710902 Institutional research plan: CEZ:AV0Z20710524 Keywords : non-linear vibration * quasi-periodic response * spherical pendulum Subject RIV: JM - Building Engineering http://dx.doi.org/10.4203/ccp.96.77

Náprstek, Ji?í; Fischer, Cyril

426

International Nuclear Information System (INIS)

The inversion of the initial periodic potential by its transformation in supersymmetry approach with exact conservation of spectral structure and creation of bound state in the lowest forbidden zone is discovered. This inversion appears in many other cases of the inverse problem transformations, but it has not been noted before. Now we have revealed it due to the choice of the initial 'Dirac comb'. The inversion of the singular ?-barriers looks especially clear against a background of finite potential corrections. (author). 19 refs., 8 figs

427

The RTA betatron-node experiment: Limiting cumulative BBU growth in a linear periodic system

International Nuclear Information System (INIS)

The successful operation of a Two-Beam accelerator based on extended relativistic klystrons hinges upon decreasing the cumulative dipole BBU growth from an exponential to a more manageable linear growth rate. The authors describe the theoretical scheme to achieve this, and a new experiment to test this concept. The experiment utilizes a 1-MeV, 600-Amp, 200-ns electron beam and a short beamline of periodically-spaced rf dipole-mode pillbox cavities and solenoid magnets for transport. Descriptions of the beamline are presented, followed by theoretical studies of the beam transport and dipole-mode growth

428

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

429

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

430

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

431

Taking into account period variations and actuators saturation in sampled-data systems

This paper deals with the problem of stability and stabilization of sampled-data systems under asynchronous samplings and actuators saturation. The method is based, on the first hand, on the use of a novel class of Lyapunov functionals whose derivative is negative along the trajectories of the continuous-time model of the sampled data system. It is shown that this fact guarantees that a quadratic Lyapunov function is strictly decreasing for the discrete-time asynchronous system. On the other ...

Seuret, Alexandre; Gomes Da Silva, Joa?o Manoel

2012-01-01

432

The decentralized stochastic control of a linear dynamic system consisting of several subsystems is considered. A two-level approach is used by the introduction of a coordinator who collects measurements from the local controllers periodically and in return transmits coordinating parameters. Two types of coordination are considered: open-loop feedback and closed loop. The resulting control laws are found to be intuitively attractive.

Chong, C.-Y.; Athans, M.

1975-01-01

433

This study treats the probabilistic safety stock n-items inventory system having varying order cost and zero lead-time subject to two linear constraints. The expected total cost is composed of three components: the average purchase cost; the expected order cost and the expected holding cost. The policy variables in this model are the number of periods Nr* and the optimal maximum inventory level Qmr* and the minimum expected total cost. We can obtain the optimal values of these policy variable...

Fergany, Hala A.

2005-01-01

434

Problem statement: This study treats the probabilistic safety stock n-items inventory system having varying holding cost and zero lead-time subject to linear constraint. Approach: The expected total cost is composed of three components: the average purchase cost; the expected order cost and the expected holding cost. Results: The policy variables for this model are the number of periods N*r and the optimal maximum inventory level Q*mr and the minimum expected total cost. Conclusion/Recom...

El-sodany, Naglaa H.

2011-01-01

435

We analyze a ultracold fermionic atom system in a three dimensional optical lattice with a confinement harmonic potential, using the Hubbard model, and time-dependent Gutzwiller variational approach for numerical calculation. Our study is focused on the time evolution of the particle transfer when the lattice potential is modulated by adding a periodic one. The choice of the parameters such as the modulation frequency and amplitude and the particle number affects the particl...

Inoue, Motoyoshi; Nakamura, Yusuke; Yamanaka, Yoshiya

2013-01-01

436

A radar-based analysis of the structure, motion, and rainfall variability of westward-propagating squall-line mesoscale convective systems (SLMCSs) in Niamey, Niger, during the African Monsoon Multidisciplinary Activities (AMMA) 2006 special observing period is combined with an analysis of 700-mb (hPa) winds and relative vorticity to study the relationship between SLMCSs and African easterly waves (AEWs). Radar results show that SLMCSs were the most important rainmakers in Niamey and accounte...

Williams, Earle R.; Rickenbach, Thomas; Guy, Nick; Nieto Ferreira, Rosana

2009-01-01

437

Decay of MHD Turbulence before the Final Period for Four-point Correlation in a Rotating System

The aim of this study is to determine decay of magnetic field fluctuations in MHD turbulence for four-point correlation in a rotating system before the final period. Two, three and four point correlation equations have been obtained and the set of correlation equations is made determinate by neglecting the quintuple correlations in comparison to the third and fourth order correlation terms. The correlation equations are converted to spectral form by taking their Fourier-transforms. Finally, i...

Bkar Pk, M. A.; Alam Sarker, M. S.; Azad, M. A. K.

2013-01-01

438

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...

Hine, N. D. M.; Dziedzic, J.; Haynes, P. D.; Skylaris, C. K.

2011-01-01

439

Quasi-gradient systems, modulational dichotomies, and stability of spatially periodic patterns

Extending the approach of Grillakis-Shatah-Strauss, Bronski-Johnson-Kapitula, and others for Hamiltonian systems, we explore relations between the constrained variational problem $\\min_{X:C(X)=c_0} \\mathcal{E}(X)$, $c_0\\in \\RM^r$, and stability of solutions of a class of degenerate "quasi-gradient" systems $dX/dt=-M(X)\

Pogan, Alin; Zumbrun, Kevin

2012-01-01

440

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

441

International Nuclear Information System (INIS)

This paper incorporates the effects of two types of human error in a model for determining the optimal time between inspections for a safety system. The possibility that a bad safety system is undetected upon inspection (Type B human error), as well as the possibility that a good safety system is inadvertently left in a bad state after the inspection (Type A human error), are considered. A Markov model is developed for the steady-state availability of the safety system which is then used to determine the optimum time between inspections which either maximizes the availability or minimizes the combined inspection and unavailability costs. The safety system failure (hazard) rate need not be constant. The optimum time between inspections increases as the probability of a Type A error increases and a Type B error decreases. The optimum availability decreases and the optimum total cost increases as the error probabilities increase

442

We introduce a regularization procedure to define electrostatic energies and forces in a slab system of thickness h that is periodic in two dimensions and carries a net charge. The regularization corresponds to a neutralization of the system by two charged walls and can be viewed as the extension to the two-dimensional (2D)+h geometry of the neutralization by a homogeneous background in the standard three-dimensional Ewald method. The energies and forces can be computed efficiently by using a...

Ballenegger, V.; Arnold, A.; Cerda, J. J.

2009-01-01

443

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

444

International Nuclear Information System (INIS)

The salient features of periodically modulated photoacoustic (PA), photothermal radiometry (PTR) and photopyroelectric (PPE) methods are reviewed with emphasis on their use for characterization of layered samples. Using a general one-dimensional (1-D) heat diffusion model, explicit solutions for up to six layers are given in terms of thermal impedances. Two typical model configurations can be transformed and combined using symmetry properties in order to match a particular excitation/cell configuration couple. Different special cases allow for simultaneous measurement of two thermal parameters. For temperature-dependent investigations the direct temperature-conversion feature of the PPE method is advantageous. We show results on the temperature calibration of LiTaO3 and PVDF pyroelectric sensors.

445

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 c