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
Some comments on the views of Niaz, Rodriguez and Brito on Mendeleev's periodic system
Scientific Electronic Library Online (English)
Eric, Scerri.
Full Text Available Many articles have been written about the value of incorporating an understanding of history and philosophy of science into science education and this has included the teaching of chemistry. Given the immense role that the periodic table plays in chemistry it is important to be clear about a histori [...] cal and philosophical perspective on the periodic table and its possible ramifications for the way in which chemistry is presented. The article presents a critique of a paper by Niaz, Rodriguez and Brito who have addressed the relevance of historical and philosophical aspects of the periodic table in an article in which they have claimed that Mendeleev's periodic table should be regarded as a theory. In addition they have claimed that Mendeleev was a supporter of the atomic theory and have addressed some general philosophical questions concerning inductivism and the role of prediction and accommodation in the acceptance of scientific discoveries.
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.
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
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
Directory of Open Access Journals (Sweden)
Khazan A.
2009-07-01
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.
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)
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 6â‰¤nâ‰¤8), and at the elements with 4f-shell, contained k electrons in 4f-shell, at which the sum k+nâ‰¥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 1â‰¤nâ‰¤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 of magnetic flux)
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)
Superconductivity, antiferromagnetism and ferromagnetism in periodic table of D.I. Mendeleev
International Nuclear Information System (INIS)
Definite regularity in the distribution of ferromagnetic, antiferromagnetic and superconducting elements is observed in the periodic table starting with the 4th period. Elements with superconductivity, by which d-shells start to fill up, are at the beginning of each period; then follow antiferromagnetics and ferromagnetics (in 4th period and lanthanides), or elements without any of the three listed order types (5th period and 6th period), in which the d (f)-shells continue to fill up almost exceedingly; then again appear superconductors by filling the p-shell up to the number is equal to 4. We calculated the radii of the external d (f)- and p-orbitals and the nearest to them orbitals with the Slater method. These trends were explained by distinction of degree of division of the external d (f)- or p-orbitals of the neighboring atoms in the crystal. Largest division occurs in ferromagnetics. In antiferromagnetics it is smaller than in ferromagnetics. It is demonstrated that in the superconducting crystals the external dor p-shells approach the nucleus of neighboring atoms are much closely those for ferromagnetic or antiferromagnetic crystals. Furthermore the external d- or p-shells of some elements in the 5th and 6th periods approach the deeper shells of neighboring atoms. Hence the electron in this shell is situated in neighboring atoms in a different electric field from its own. This fact is open to speculation that the separation of spin and charge in electron, disposed on the external d- or p-orbitals, is quite possible. The charges without spin become bosons. Spins that have the magnetic moments are ordered antiparallel in pairs. Magnetic field transfers this pair in a parallel state and a magnetic flux component along of magnetic field from the pair is equal to one fluxon (the quant of the magnetic flux).
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
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.)
Geometrochemistry vs Soft Computing of Mendeleev's Brain.
Czech Academy of Sciences Publication Activity Database
Gottvald, Aleš
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
Czech Academy of Sciences Publication Activity Database
Štrbá?ová, So?a
Oxford : Oxford University Press, 2015 - (Kaji, M.; Kragh, H.; Pallo, G.), s. 121-149 ISBN 978-0-19-020007-7 R&D Projects: GA AV ?R IAAX00630801 Institutional support: RVO:68378114 Keywords : D. I. Mendeleev * B. Brauner * history of the periodic system of elements Subject RIV: AB - History
The role of the Czech chemists in reception and dissemination of the periodic system in Europe.
Czech Academy of Sciences Publication Activity Database
Štrbá?ová, So?a
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
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
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
International Nuclear Information System (INIS)
Reports of the XVII Mendeleev congress on general and applied chemistry, volume 4 (Kazan', 21 - 26 September, 2003) are presented. Current status and prospects of chemical science, biomolecular chemistry and biotechnology, petrochemistry and catalysis, chemical education, as well as some ecological problems are treated in the collection. Materials of the Russian-French symposium: Supramolecular systems in chemistry and biology, Russian-American symposium on chemical education as well as symposium devoted to the 100 anniversary from the discovery of chromatography by Russian scientist M.S. Tsvet are included in the volume. Prospects for the development of chromatography and applications of this method are discussed
Directory of Open Access Journals (Sweden)
Raos, N.
2011-12-01
Full Text Available The Croatian (Yugoslav Academy of Sciences and Arts was the first academy to elect D. I. Mendeleev as its honorary member (1882, whereas the periodic table of the elements has been taught regularly at the Zagreb University since 1888. The early interest of Croatian chemists in the periodic table should be attributed primarily to their pan-Slavic attitude, particularly as proof that Slavic people were able to produce "their own Newtons" (M. V. Lomonosov and D. I. Mendeleev. Such enthusiastic views, however, did not help in analyzing the contribution of Mendeleev and other scientists to the discovery and development of the periodic table of the elements.
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 Zâ‰¥118 are also considered.
Holonomic systems for period mappings
International Nuclear Information System (INIS)
Period mappings were introduced in the sixties [4] to study variation of complex structures of families of algebraic varieties. The theory of tautological systems was introduced recently [7,8] to understand period integrals of algebraic manifolds. In this paper, we give an explicit construction of a tautological system for each component of a period mapping. We also show that the D-module associated with the tautological system gives rise to many interesting vanishing conditions for period integrals at certain special points of the parameter space
Periodic systems filtering and control
Bittanti, Sergio
2008-01-01
This book offers a comprehensive treatment of the theory of periodic systems, including the problems of filtering and control. It covers an array of topics, presenting an overview of the field and focusing on discrete-time signals and systems..
Polyak, L.; Curry, W.B.; Darby, D.A.; Bischof, J.; Cronin, T. M.
2004-01-01
Distinct cyclicity in lithology and microfaunal distribution in sediment cores from the Mendeleev Ridge in the western Arctic Ocean (water depths ca. 1. 5 km) reflects contrasting glacial/interglacial sedimentary patterns. We conclude that during major glaciations extremely thick pack ice or ice shelves covered the western Arctic Ocean and its circulation was restricted in comparison with interglacial, modern-type conditions. Glacier collapse events are marked in sediment cores by increased contents of ice-rafted debris, notably by spikes of detrital carbonates and iron oxide grains from the Canadian Arctic Archipelago. Composition of foraminiferal calcite ?? 18O and ??13C also shows strong cyclicity indicating changes in freshwater balance and/or ventilation rates of the Arctic Ocean. Light stable isotopic spikes characterize deglacial events such as the last deglaciation at ca. 12 14C kyr BP. The prolonged period with low ??18O and ??13C values and elevated contents of iron oxide grains from the Canadian Archipelago in the lower part of the Mendeleev Ridge record is interpreted to signify the pooling of freshwater in the Amerasia Basin, possibly in relation to an extended glaciation in arctic North America. Unique benthic foraminiferal events provide a means for an independent stratigraphic correlation of sedimentary records from the Mendeleev Ridge and other mid-depth locations throughout the Arctic Ocean such as the Northwind and Lomonosov Ridges. This correlation demonstrates the disparity of existing age models and underscores the need to establish a definitive chronostratigraphy for Arctic Ocean sediments. ?? 2003 Elsevier B.V. All rights reserved.
Park, K.; Kim, S.; Khim, B. K.; Wang, R.; Mei, J.; Xiao, W.; Polyak, L. V.
2014-12-01
Late Quaternary deep sea sediments in the Arctic Ocean are characterized by brown layers intercalated with yellowish to olive gray layers. It has been known 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 (~1.0 Ma) of core MA01 was tentatively decided by correlation of sediment color cycles, XRF Mn and Ca cycles, and geomagnetic inclinations with core HLY0503-8JPC (Adler et al., 2009) and core HLY0503-06JPC(Cronin et al., 2013) that were also collected from the Mendeleev Ridge area. A total of 23 brown layers are characterized by low L* and b*, high Mn concentration, and abundant foraminifera. In contrast, 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 are accompanied with the coarse-grained (>63 ?m) fractions (i.e., IRD) both in brown and gray layers. A strong positive 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 fraction which mainly originated from the Canadian Arctic Archipelago. In addition, high kaolinite/chlorite (K/C) ratios mostly correspond to CaCO3 peaks, also suggesting that the fine-grained particles in the Mendeleev Ridge were transported from the northern coasts of the Alaska and Canada. Thus, the Beaufort Gyre, the predominant surface current in the western Arctic Ocean, has played an important role in the sediment delivery to the Mendeleev Ridge. It is worthy of note that 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.
From the other oil field : Mendeleev, the West and the Russian oil industry
Energy Technology Data Exchange (ETDEWEB)
Butorac, M.
2004-07-01
This thesis examines whether Dmitrii Ivanovich Mendeleev, a Russian chemist, was open to Western ideas and capital in the Russian petroleum industry. Five of Mendeleev's business trips which took place between 1863 and 1886 were studied. They included trips to France, the United States and the Caucasus. Personal letters, diaries, and published articles were produced from each trip. This thesis looks at both published and unpublished archival documents to reveal much about the history of the Russian petroleum industry, its industrialists and Mendeleev's personality. The first chapter summarizes Mendeleev's important formative years before he began to work in the oil industry in 1863. His youthful travels around Europe, studies in Germany and personal inclinations made him a multilingual and cosmopolitan individual. The following 5 chapters examined Mendeleev's trips to study the industry, and an epilogue recounts his final years. It was concluded that contrary to Soviet teaching, Mendeleev was open to the West. His sole request was that Western ideas and capital help develop the Russian oil industry to produce large volumes of inexpensive kerosene for the Russian population.
Soliton Management in Periodic Systems
Malomed, Boris A
2006-01-01
During the past ten years, there has been intensive development in theoretical and experimental research of solitons in periodic media. This book provides a unique and informative account of the state-of-the-art in the field. The volume opens with a review of the existence of robust solitary pulses in systems built as a periodic concatenation of very different elements. Among the most famous examples of this type of systems are the dispersion management in fiber-optic telecommunication links, and (more recently) photonic crystals. A number of other systems belonging to the same broad class of spatially periodic strongly inhomogeneous media (such as the split-step and tandem models) have recently been identified in nonlinear optics, and transmission of solitary pulses in them was investigated in detail. Similar soliton dynamics occurs in temporal-domain counterparts of such systems, where they are subject to strong time-periodic modulation (for instance, the Feshbach-resonance management in Bose-Einstein conde...
Jang, Kwangchul; Han, Yeongcheol; Huh, Youngsook; Nam, Seung-Il; Stein, Ruediger; Mackensen, Andreas; Matthiessen, Jens
2013-05-01
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.
Stratigraphy, Structure, and Origin; A Geophysical Survey of the Mendeleev Ridge
Dove, D.; Coakley, B.; Hopper, J.
2006-12-01
The Mendeleev Ridge is a broad, aseismic ridge that extends from the Siberian Shelf into the central Arctic Ocean. While it is continuous with the Alpha Ridge and is inferred to be an oceanic plateau, it may have had a distinct and separate history. The origin of the Mendeleev ridge has only rarely been visited and, as a result, understanding the history of this region has largely been based on the presumption of a common origin for both features. In late summer 2005, a geophysical survey was conducted from USCGC Healy over the Mendeleev Ridge as part of a trans-arctic crossing. During this survey ~730 km of seismic reflection data was recovered over the ridge along with co-registered gravity and bathymetry data and seismic refraction profiles. The seismic source was two 250 cu in G-guns. The streamer length was limited by ice conditions to 300 meters. Wear and tear caused by towing the streamer through the ice pack eliminated hydrophones, so the number of active channels ranged from 24 to as few as 11. The seismic reflection data requires significant trace editing to eliminate random electrical noise and frequency-wave number filtering to eliminate low velocity noise caused by the streamer traveling through heavy ice. After trace editing the data are stacked and migrated with constant water velocity. Stacking velocities are used as input into initial ray tracing models. Derived boundary velocities from ray tracing models will be reapplied to the migration of reflection data and are converted through empirical relationships into densities, and used as input into gravity models. Brute stacked reflection images of the Mendeleev Ridge reveal pervasive extensional faulting of the basement and lower sediment layers, and a continuous, undeformed pelagic sediment layer mantling the ridge, indicative of recent tectonic inactivity. The age of the unconformity underlying this layer should date the end of significant deformation of the Alpha and Mendeleev Ridges. Consistency of modeled seismic velocities from the upper basement will provide some insight into the nature of the crustal material. Upper basement velocities estimated from the sonobuoy data range from 3.7-5.0 km/s, suggestive of a heterogeneous upper crust. Initial gravity models suggest that much of the amplitude variation over the Mendeleev Ridge is accommodated by invoking a single, continuous density layer for the crust. Future work will include: developing a structural map of the Mendeleev ridge as well as the refining of both the ray-tracing and gravity modeling in an attempt to better understand the crustal style of the ridge.
EDUCATION SYSTEM IN VEDIC PERIOD
Directory of Open Access Journals (Sweden)
R.B.KOKATANUR
2013-05-01
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 â€“ 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.
Park, Kwang-Kyu; Kim, Sunghan; Khim, Boo-Keun; Xiao, Wenshen; Wang, Rujian
2014-05-01
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.
QM/MM description of periodic systems
Doll, K
2015-01-01
A QM/MM implementation for periodic systems is reported. This is done for the case of molecules and for systems with two and three-dimensional periodicity, which is suitable to model electrolytes in contact with electrodes. Tests on different water-containing systems, ranging from the water dimer up to liquid water indicate the correctness of the scheme. Furthermore, molecular dynamics simulations are performed, as a possible direction to study realistic systems.
Periodic testing of instrumentation and control systems
International Nuclear Information System (INIS)
During normal operation, protection systems are on standby and possible failure of system components may therefore go undetected. Their ability to function as intended, should they be initiated after a long period of time, is thus questionable. For this reason, French as well as international rules require that protection systems be subjected to periodic tests. Because of the equipment available when the units in the French 900-MW(electric) series were designed, the instrumentation and control systems were equipped with manual periodic test systems. This was the case with the reactor protection system (RPS) periodic test equipment where the manual procedures relied on the manipulation of a large number of switches and push buttons. This manual test equipment has been successfully replaced on the 28 units in the French 900-MW(electric) series by the automatic tester discussed in this paper
Long Periodic Terms in the Solar System
Bretagnon, P.
1982-01-01
The long period variations of the first eight planets in the solar system are studied. First, the Lagrangian solution is calculated and then the long period terms with fourth order eccentricities and inclinations are introduced into the perturbation function. A second approximation was made taking into account the short period terms' contribution, namely the perturbations of first order with respect to the masses. Special attention was paid to the determination of the integration constants. The relative importance of the different contributions is shown. It is useless, for example, to introduce the long period terms of fifth order if no account has been taken of the short period terms. Meanwhile, the terms that have been neglected would not introduce large changes in the integration constants. Even so, the calculation should be repeated with higher order short period terms and fifth order long periods.
Bifurcation of critical periods of polynomial systems
Fer?ec, Brigita; Levandovskyy, Viktor; Romanovski, Valery G.; Shafer, Douglas S.
2015-10-01
We describe a general approach to studying bifurcations of critical periods based on a complexification of the system and algorithms of computational algebra. Using this approach we obtain upper bounds on the number of critical periods of several families of cubic systems. In some cases we overcome the problem of nonradicality of a relevant ideal by moving it to a subalgebra generated by invariants of a group of linear transformations.
Phase splitting for periodic Lie systems
Energy Technology Data Exchange (ETDEWEB)
Flores-Espinoza, R; Vorobiev, Yu M [Departamento de Matematicas, Universidad de Sonora (Mexico); De Lucas, J, E-mail: rflorese@gauss.mat.uson.m, E-mail: delucas@impan.gov.p, E-mail: yurimv@guaymas.uson.m [Departamento de Fisica Teorica, Universidad de Zaragoza (Spain)
2010-05-21
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.
Attractors of the periodically forced Rayleigh system
Directory of Open Access Journals (Sweden)
Petre Bazavan
2011-07-01
Full Text Available The autonomous second order nonlinear ordinary differential equation(ODE introduced in 1883 by Lord Rayleigh, is the equation whichappears to be the closest to the ODE of the harmonic oscillator withdumping.In this paper we present a numerical study of the periodic andchaotic attractors in the dynamical system associated with the generalized Rayleigh equation. Transition between periodic and quasiperiodic motion is also studied. Numerical results describe the system dynamics changes (in particular bifurcations, when the forcing frequency is varied and thus, periodic, quasiperiodic or chaotic behaviour regions are predicted.
The design of periodic beam transport systems
International Nuclear Information System (INIS)
Periodic beam-transport systems have several advantages including insensitivity to errors, minimum magnet apertures, and use of standardized components. A simple procedure is given for the design of modules, with and without bending magnets, that have the same matched beam properties. These modules can be combined in certain ways to produce systems that are achromatic and require a minimum number of matching elements
Localized states in periodically forced systems.
Gandhi, Punit; Knobloch, Edgar; Beaume, Cédric
2015-01-23
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. PMID:25659000
Fitting of local densities in periodic systems
Maschio, Lorenzo
2008-01-01
We present a formalism for density fitting, a widely used method in molecular context, to approximate the electron repulsion integrals between local densities in periodic systems. An efficient treatment is achieved through a separation of the fitting into a reciprocal space part, done with an extended, but momentless fitting basis set, and a direct space part with a small, local set of usual Gaussian-type orbitals. This approach can be applied to periodic Hartree-Fock, Kohn-Sham, post-Hartree...
Periodic solutions of dissipative systems revisited
Directory of Open Access Journals (Sweden)
Górniewicz Lech
2006-01-01
Full Text Available We reprove in an extremely simple way the classical theorem that time periodic dissipative systems imply the existence of harmonic periodic solutions, in the case of uniqueness. We will also show that, in the lack of uniqueness, the existence of harmonics is implied by uniform dissipativity. The localization of starting points and multiplicity of periodic solutions will be established, under suitable additional assumptions, as well. The arguments are based on the application of various asymptotic fixed point theorems of the Lefschetz and Nielsen type.
Periodic testing of instrumentation and control systems
International Nuclear Information System (INIS)
During normal operation, protection systems are on stand-by; therefore possible failure of system components may go undetected. The ability of these systems to function as intended, should they be initiated after a long period of time on stand-by, is thus questionable. For this reason, French as well as international rules require that protection systems be subjected to periodic tests. Given the equipment available when the units in the French 900 MW(e) series were designed, the instrumentation and control systems were equipped with manual periodic test systems. In the case of the reactor protection system, the manual test equipment has been replaced successfully on the 28 units in the French 900 MW(e) series by the automatic tester discussed in the paper. The manual test system is still used with the process instrumentation system which receives analogue signals from sensors or transmitters connected to the process equipment. These input signals are subjected to varying degrees of signal conditioning, including, in some cases, the combining of some of the signals. The electronic conditioning circuits generate a signal that is the direct input to a threshold detector. In practice, each element in the instrumentation channel, including the signal conditioning unit, has an uncertainty associated with it. It is important to check periodically that the actual trip values for the input variables are lower than the physical limits established by the safety studies. Framatome has carried out a study for Electricite de France with the objective both of modernizing this operation and of considering, as a possibility, the complete automation of the testing. This second subject is also discussed in the paper. (author). 2 figs
Periodic thermodynamics of isolated quantum systems.
Lazarides, Achilleas; Das, Arnab; Moessner, Roderich
2014-04-18
The nature of the behavior of an isolated many-body quantum system periodically driven in time has been an open question since the beginning of quantum mechanics. After an initial transient period, such a system is known to synchronize with the driving; in contrast to the nondriven case, no fundamental principle has been proposed for constructing the resulting nonequilibrium state. Here, we analytically show that, for a class of integrable systems, the relevant ensemble is constructed by maximizing an appropriately defined entropy subject to constraints, which we explicitly identify. This result constitutes a generalization of the concepts of equilibrium statistical mechanics to a class of far-from-equilibrium systems, up to now mainly accessible using ad hoc methods. PMID:24785013
Tracer diffusion in small periodic systems
Perondi, L. F.; Binder, P.-M.
1993-06-01
We study tracer diffusion in lattices consisting of identical replicas of smaller systems. We develop an exact enumeration method for computing the diffusion coefficient, which involves mapping the system into a single-particle random walk in a different geometry in configuration space. In one dimension the simulations show a crossover to normal diffusion, in agreement with mode-coupling results. In two dimensions the diffusion coefficient is enhanced by finite-size effects: we show this for a 3×3 periodic system. We find exact solutions for the single-vacancy case; our simulations agree with theory essentially to machine precision. We also develop an approximate theory for the periodic system for arbitrary concentrations of background particles, in close agreement with the numerical results.
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.)
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)
Effective imaging systems based on periodic lattices
Energy Technology Data Exchange (ETDEWEB)
Gennarelli, Gianluca, E-mail: gennarelli.g@irea.cnr.it; Soldovieri, Francesco [Institute for Electromagnetic Sensing of the Environment, National Research Council of Italy, Via Diocleziano 328, 80124 Napoli (Italy); Persico, Raffaele [Institute for Archaeological and Monumental Heritage, National Research Council of Italy, Via Monteroni, Campus Universitario, 73100 Lecce (Italy)
2014-05-12
A crucial question in imaging problems from diffracted wavefields is the evaluation of the information content of data and the related reconstruction performance in terms of spatial resolution. It is well-known that full-view tomographic reconstructions are characterized by resolution limits of the order of one half propagated wavelength. These limits are further deteriorated when a truncated measurement domain is exploited for the imaging. In this Letter, we show that when the imaging system comprises a periodic layer located between a linear array of probes and the investigated domain, the resolution limits are substantially improved compared to the case of a homogenous scenario. This intriguing result is a consequence of the multiscattering effects arising from the periodicity of the structure. The study provides physical insight supported by mathematical arguments paving the way to the development of effective imaging systems requiring few radiating elements.
Dynamical studies of periodic and disordered systems
Energy Technology Data Exchange (ETDEWEB)
Kopidakis, G.
1995-11-01
The time evolution of two classes of systems is studied with real time molecular dynamics simulations. The first consists of a coupled electron-lattice system. For a periodic system, we present results for the time evolution of a one-dimensional system consisting of an electron, described by a tight-binding Hamiltonian, and a harmonic lattice, coupled by a deformation-type potential. We solve numerically the nonlinear system of equations of motion for this model in order to study the effects of varying the electronic effective mass for several initial conditions and coupling strengths. A large effective mass favors localized polaron formation for initially localized electrons. For initially extended electronic states, increasing the effective mass of an electron initially close to the bottom of the band makes localization more difficult, while for an initially highly excited electronlocalized polaron formation is possible only when the electronic effective mass and the atomic masses of the lattice become of the same order.
Poissonian noise assisted transport in periodic systems
Spiechowicz, J.; ?uczka, J.
2015-10-01
We revisit the problem of transport of a harmonically driven inertial particle moving in a symmetric periodic potential, subjected to unbiased non-equilibrium generalized white Poissonian noise and coupled to a thermal bath. Statistical asymmetry of Poissonian noise is sufficient to induce transport and under the presence of external harmonic driving this system exhibits a phenomenon of multiple velocity reversals. Consequently, one can manipulate the direction of transport by simply adjusting the parameters of externally applied forces.
Periodic Solutions for Highly Nonlinear Oscillation Systems
DEFF Research Database (Denmark)
Ghadimi, M; Barari, Amin
2012-01-01
In this paper, Frequency-Amplitude Formulation is used to analyze the periodic behavior of tapered beam as well as two complex nonlinear systems. Many engineering structures, such as offshore foundations, oil platform supports, tower structures and moving arms, are modeled as tapered beams. The 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.
Microwave realisation of a periodically driven system
Gehler, S; Schindler, C; Kuhl, U; Stoeckmann, H -J
2013-01-01
A realisation of a periodically driven microwave system is presented. The principal element of the scheme is a variable capacity, i.e. a varicap, introduced as an element of the resonant circuit. Sideband structures corresponding to different driving signals, have been measured experimentally. In the linear regime we observed sideband structures with specific shapes. The main peculiarities of these shapes can be explained within a semiclassical approximation. A good agreement between experimental data and theoretical expectations has been found.
Central configurations, periodic orbits, and Hamiltonian systems
Llibre, Jaume; Simó, Carles
2015-01-01
The notes of this book originate from three series of lectures given at the Centre de Recerca Matemàtica (CRM) in Barcelona. The first one is dedicated to the study of periodic solutions of autonomous differential systems in Rn via the Averaging Theory and was delivered by Jaume Llibre. The second one, given by Richard Moeckel, focusses on methods for studying Central Configurations. The last one, by Carles Simó, describes the main mechanisms leading to a fairly global description of the dynamics in conservative systems. The book is directed towards graduate students and researchers interested in dynamical systems, in particular in the conservative case, and aims at facilitating the understanding of dynamics of specific models. The results presented and the tools introduced in this book include a large range of applications.
Ortiz, J. D.; Polyak, L.; Adler, R.; Jakobsson, M.; Darby, D.
2007-12-01
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.
On periodic orbits in discrete-time cascade systems
Directory of Open Access Journals (Sweden)
Xiao-Song Yang
2006-12-01
Full Text Available We present some results on existence, minimum period, number of periodic orbits, and stability of periodic orbits in discrete-time cascade systems. Some examples are presented to illustrate these results.
On periodic orbits in discrete-time cascade systems
Xiao-Song Yang; Huimin Li
2006-01-01
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.
Dynamical system theory of periodically collapsing bubbles
Yukalov, V I; Sornette, D
2015-01-01
We propose a reduced form set of two coupled continuous time equations linking the price of a representative asset and the price of a bond, the later quantifying the cost of borrowing. The feedbacks between asset prices and bonds are mediated by the dependence of their "fundamental values" on past asset prices and bond themselves. The obtained nonlinear self-referencing price dynamics can induce, in a completely objective deterministic way, the appearance of periodically exploding bubbles ending in crashes. Technically, the periodically explosive bubbles arise due to the proximity of two types of bifurcations as a function of the two key control parameters $b$ and $g$, which represent, respectively, the sensitivity of the fundamental asset price on past asset and bond prices and of the fundamental bond price on past asset prices. One is a Hopf bifurcation, when a stable focus transforms into an unstable focus and a limit cycle appears. The other is a rather unusual bifurcation, when a stable node and a saddle...
Scientific Electronic Library Online (English)
Helena S. A., Leite; Paulo A., Porto.
2015-05-01
Full Text Available [...] Abstract in english The aim of this paper was to analyze the historical approaches to the periodic table in general chemistry textbooks used in Brazilian universities in the twentieth century. Textbooks were qualitatively analyzed according to the following criteria: position of the discussion about the periodic table [...] in the book; presence or absence of a specific chapter on the subject; presentation of attempts to classify chemical elements before Mendeleev; presentation of the construction process of the periodic table by Mendeleev; identification of problems in the original table; discussion of Mendeleev's predictions about unknown elements; organization of the periodic table; periodic properties presented and discussed; and the enunciation of the periodic law. The analysis revealed different approaches at specific periods of the twentieth century, from more descriptive approaches to emphasis on attempts to explain the periodic table in terms of atomic orbitals. These changes point to different ways of understanding chemistry during the period studied.
Scientific Electronic Library Online (English)
Mario, Tolentino; Romeu C., Rocha-Filho; Aécio Pereira, Chagas.
1997-02-01
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.
Directory of Open Access Journals (Sweden)
Mario Tolentino
1997-02-01
Full Text Available A history of the periodic table of the elements is presented, from the first tentative classifications, passing through Meyer and Mendeleev, up to recent speculations on super-heavy elements still to be synthesized. Many of the discussions and discoveries related to chemical elements and their proper periodic classification are also presented.
Mario Tolentino; Rocha-Filho, Romeu C.; Aécio Pereira Chagas
1997-01-01
A history of the periodic table of the elements is presented, from the first tentative classifications, passing through Meyer and Mendeleev, up to recent speculations on super-heavy elements still to be synthesized. Many of the discussions and discoveries related to chemical elements and their proper periodic classification are also presented.
Periodic Table of the Elements in the Perspective of Artificial Neural Networks
Lemes, Mauricio R.; Dal Pino, Arnaldo
2011-01-01
Although several chemical elements were not known by end of the 19th century, Mendeleev came up with an astonishing achievement, the periodic table of elements. He was not only able to predict the existence of (then) new elements, but also to provide accurate estimates of their chemical and physical properties. This is a profound example of the…
Adaptive Scheduling in Real-Time Systems Through Period Adjustment
Dwivedi, Shri Prakash
2012-01-01
Real time system technology traditionally developed for safety critical systems, has now been extended to support multimedia systems and virtual reality. A large number of real-time application, related to multimedia and adaptive control system, require more flexibility than classical real-time theory usually permits. This paper proposes an efficient adaptive scheduling framework in real-time systems based on period adjustment. Under this model periodic task can change their execution rates b...
International Nuclear Information System (INIS)
Works devoted to the problems of radioecology, radiochemistry, ecological monitoring, human health in zones subjected to radioactive contamination as a result of the Chernobyl accident, were presented at the 15. Mendeleev congress of general and applied chemistry which took place in Obninsk in 1993
International Nuclear Information System (INIS)
Ecological aspects of nuclear-fuel engineering cycle and radiochemical technologies, radioactive waste processing and water purification, accidents at NPP and their consequences, ecological problems of industry conversion were discussed at the 15th Mendeleev's meeting on general and applied chemistry
Effective Hamiltonian approach to periodically perturbed quantum optical systems
Energy Technology Data Exchange (ETDEWEB)
Sainz, I. [Centro Universitario de los Lagos, Universidad de Guadalajara, Enrique Diaz de Leon, 47460 Lagos de Moreno, Jal. (Mexico)]. E-mail: isa@culagos.udg.mx; Klimov, A.B. [Departamento de Fisica, Universidad de Guadalajara, Revolucion 1500, 44410 Guadalajara, Jal. (Mexico)]. E-mail: klimov@cencar.udg.mx; Saavedra, C. [Center for Quantum Optics and Quantum Information, Departamento de Fisica, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile)]. E-mail: csaaved@udec.cl
2006-02-20
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.
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
Periodic Behaviors in Constrained Multi-agent Systems
Yang, Tao; Meng, Ziyang; Dimarogonas, Dimos V.; Johansson, Karl H.
2014-01-01
In this paper, we provide two discrete-time multi-agent models which generate periodic behaviors. The first one is a multi-agent system of identical double integrators with input saturation constraints, while the other one is a multi-agent system of identical neutrally stable system with input saturation constraints. In each case, we show that if the feedback gain parameters of the local controller satisfy a certain condition, the multi-agent system exhibits a periodic solut...
Fredholm operators, evolution semigroups, and periodic solutions of nonlinear periodic systems
Miyazaki, Rinko; Kim, Dohan; Naito, Toshiki; Shin, Jong Son
2014-12-01
Let X be a Banach space and L the generator of the evolution semigroup associated with the ?-periodic evolutionary process {U(t,s)}t?s on the space P?(X) of all ?-periodic continuous X-valued functions. We give criteria for the existence of periodic solutions to nonlinear systems of the form Lp=-?F(p,?) under the condition that 1 is a normal eigenvalue of the monodromy operator U(?,0). The proof is based on a new decomposition of the space P?(X) by constructing a right inverse of L.
Computer-based Periodicals Management System in SAC Library
Directory of Open Access Journals (Sweden)
D.R. Patel,
1995-05-01
Full Text Available The paper discusses the efforts made for a Periodicals Management System developed and designed for implementation in SAC Library, using DBASE III software. It briefly describes the computer programmes in PMS and highlights the present system which is implemented by using 'LIBSYS', a comprehensive library software package and a multi-user system on Pentium system, under Unix environment.
An index defined by focal points for periodic hamiltonians systems
International Nuclear Information System (INIS)
Associated to an n-dimensional linear Hamiltonian system a real number ? is defined as the mean number of focal points per unit of time. For general one parameter families of Hamiltonian systems with periodic coefficients the existence and the continuity of ? can be proved. Moreover, if the periodic system is hyperbolic, ? is associated to an integer. These results are extentions of Poincare's Study of Manpertuis' focal points. (Author)
On computing normalized coprime factorizations of periodic systems
Varga, Andras
2010-01-01
A numerically reliable state space algorithm is proposed for computing normalized coprime factorizations of periodic descriptor systems. A preprocessing step is used in the algorithm to convert the initial problem for possibly non-causal systems into a simpler problem for causal periodic systems. The main computational ingredient here is the computation of a coprime factorization with causal factors which is addressed by computing right annihilators of an appropriately ...
Periodic solutions of nonautonomous differential systems modeling obesity population
Energy Technology Data Exchange (ETDEWEB)
Arenas, Abraham J. [Departamento de Matematicas y Estadistica, Universidad de Cordoba Monteria (Colombia)], E-mail: aarenas@sinu.unicordoba.edu.co; Gonzalez-Parra, Gilberto [Departamento de Calculo, Universidad de los Andes, Merida (Venezuela, Bolivarian Republic of)], E-mail: gcarlos@ula.ve; Jodar, Lucas [Instituto de Matematica Multidisciplinar, Universidad Politecnica de Valencia Edificio 8G, 2o, 46022 Valencia (Spain)], E-mail: ljodar@imm.upv.es
2009-10-30
In this paper we study the periodic behaviour of the solutions of a nonautonomous model for obesity population. The mathematical model represented by a nonautonomous system of nonlinear ordinary differential equations is used to model the dynamics of obese populations. Numerical simulations suggest periodic behaviour of subpopulations solutions. Sufficient conditions which guarantee the existence of a periodic positive solution are obtained using a continuation theorem based on coincidence degree theory.
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
Development of the safety management support system in shutdown period
Energy Technology Data Exchange (ETDEWEB)
Fujii, Masahiko; Muta, Hitoshi [Toshiba Corp., Kawasaki, Kanagawa (Japan); Saito, Hiroshi; Kato, Yoshiyuki
2000-07-01
In Japan, almost all configuration changes occur during plant shut down period. We have developed a system by which instantaneous risk during plant shutdown period is evaluated in a short time. The system is designed to allow plant personnel to easily calculate the plant risk in order to obtain and utilize risk information for safety management during shutdown period. To verify the system functions, verification tests were carried out using hypothetical refueling outage schedule in which plant configurations were changed much more frequently than in an actual refueling, outage. The system identified high-risk portion and its major contributor. Therefore we conclude that this system is useful and powerful tool for plant personnel in managing plant risk during plant shutdown period. (author)
Evidence of a multi resonant system within solar periodic activity
Vukcevic, M.A.
2004-01-01
To demonstrate a degree of correlation between periodicity in the solar activity and a multi-resonant system three examples are considered. Although only two base frequencies were employed a relatively close correlation was obtained for periodicity, amplitude's envelope and some well-known longer-term anomalies, by using a simple mathematical formula.
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)
Early warning signals of tipping points in periodically forced systems
Williamson, M. S.; Bathiany, S.; Lenton, T. M.
2015-11-01
The prospect of finding generic early warning signals of an approaching tipping point in a complex system has generated much recent interest. Existing methods are predicated on a separation of timescales between the system studied and its forcing. However, many systems, including several candidate tipping elements in the climate system, are forced periodically at a timescale comparable to their internal dynamics. Here we find alternative early warning signals of tipping points due to local bifurcations in systems subjected to periodic forcing whose time scale is similar to the period of the forcing. These systems are not in, or close to, a fixed point. Instead their steady state is described by a periodic attractor. We show that the phase lag and amplification of the system response provide early warning signals, based on a linear dynamics approximation. Furthermore, the power spectrum of the system's time series reveals the generation of harmonics of the forcing period, the size of which are proportional to how nonlinear the system's response is becoming with nonlinear effects becoming more prominent closer to a bifurcation. We apply these indicators to a simple conceptual system and satellite observations of Arctic sea ice area, the latter conjectured to have a bifurcation type tipping point. We find no detectable signal of the Arctic sea ice approaching a local bifurcation.
National Oceanic and Atmospheric Administration, Department of Commerce — This is an archive of data of 47 distinct XBT casts taken at 41 locations in the Mendeleev Ridge and Chukchi Borderland region of the Arctic between 22nd August and...
Periodic Solutions for a Discrete Mutual System with Delays
Directory of Open Access Journals (Sweden)
CHEN Da-xue
2012-01-01
Full Text Available In this paper, a discrete-time mutual system * is considered. By using coincidence degree and the related continuation the orem as well as prior estimates, easily sufficient conditions for the existence of positive periodic solutions are obtained,* if the following conditi * hold, then system has at least an w periodic solution. Our results are important complement to earlier results in the literature.(* Indicates a formula, please see the full text
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
Perturbative solution of Vlasov equation for periodically driven systems
Shah, Kushal
2015-01-01
Statistical systems with time-periodic spatially non-uniform forces are of immense importance in several areas of physics. In this paper, we provide an analytical expression of the time-periodic probability distribution function of particles in such a system by perturbatively solving the 1D Vlasov equation in the limit of high frequency and slow spatial variation of the time-periodic force. We find that the time-averaged distribution function and density cannot be written simply in terms of an effective potential, also known as the fictitious ponderomotive potential. We also find that the temperature of such systems is spatially non-uniform leading to a non-equilibrium steady state which can further lead to a complex statistical time evolution of the system. Finally, we outline a method by which one can use these analytical solutions of the Vlasov equation to obtain numerical solutions of the self-consistent Vlasov-Poisson equations for such systems.
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
Optimal periodic orbits of continuous time chaotic systems
International Nuclear Information System (INIS)
In previous work [B. R. Hunt and E. Ott, Phys. Rev. Lett. 76, 2254 (1996); Phys. Rev. E 54, 328, (1996)], based on numerical experiments and analysis, it was conjectured that the optimal orbit selected from all possible orbits on a chaotic attractor is ''typically'' a periodic orbit of low period. By an optimal orbit we mean the orbit that yields the largest value of a time average of a given smooth ''performance'' function of the system state. Thus optimality is defined with respect to the given performance function. (The study of optimal orbits is of interest in at least three contexts: controlling chaos, embedding of low-dimensional attractors of high-dimensional dynamical systems in low-dimensional measurement spaces, and bubbling bifurcations of synchronized chaotic systems.) Here we extend this previous work. In particular, the previous work was for discrete time dynamical systems, and here we shall consider continuous time systems (flows). An essential difference for flows is that chaotic attractors can have embedded within them, not only unstable periodic orbits, but also unstable steady states, and we find that optimality can often occur on steady states. We also shed further light on the sense in which optimality is ''typically'' achieved at low period. In particular, we find that, as a system parameter is tuned to be closer to a crisis of the chaotic attractor, optimality may occur at higher period. (c) 2000 The American Physical Society
Lei, Ling
2009-01-01
This work studies the stabilization for a periodic parabolic system under perturbations in the system conductivity. A perturbed system does not have any periodic solution in general. However, we will prove that the perturbed system can always be pulled back to a periodic system after imposing a control from a fixed finite dimensional subspace.
Dynamic steady state of periodically driven quantum systems
Yudin, V. I.; Taichenachev, A. V.; Basalaev, M. Yu.
2016-01-01
Using the density matrix formalism, we prove the existence of the periodic steady state for an arbitrary periodically driven system described by linear dynamic equations. This state has the same period as the modulated external influence, and it is realized as an asymptotic solution (t ?+? ) due to relaxation processes. The presented derivation simultaneously contains a simple and effective computational algorithm (without using either the Floquet or Fourier formalisms), which automatically guarantees a full account of all frequency components. As a particular example, for three-level ? system we calculate the line shape and field-induced shift of the dark resonance formed by the field with a periodically modulated phase. Also we have analytically solved a basic theoretical problem of the direct frequency comb spectroscopy, when the two-level system is driven by the periodic sequence of rectangular pulses. In this case, the radical dependence of the spectroscopy line shape on pulse area is found. Moreover, the existence of quasiforbidden spectroscopic zones, in which the Ramsey fringes are significantly reduced, is predicted. Our results have a wide area of applications in laser physics, spectroscopy, atomic clocks, and magnetometry. Also they can be useful for any area of quantum physics where periodically driven systems are considered.
On the complete ionization of a periodically perturbed quantum system
Costin, O; Rokhlenko, A
2000-01-01
We analyze the time evolution of a one-dimensional quantum system with zerorange potential under time periodic parametric perturbation of arbitrarystrength and frequency. We show that the projection of the wave function on thebound state vanishes, i.e. the system gets fully ionized, as time growsindefinitely.
Stabilization for a Periodic Predator-Prey System
Carmen Oana Tarniceriu; Sebastian Ani?a
2007-01-01
Ã¯Â»Â¿A reaction-diffusion system modelling a predator-prey system in a periodic environment is considered. We are concerned in stabilization to zero of one of the components of the solution, via an internal control acting on a small subdomain, and in the preservation of the nonnegativity of both components.
A nondestructive characterization system of periodically poled crystals
Chen, Huaixi; Zhou, Huang; Chen, Liyuan; Zou, Xiaolin; Miao, Long; Feng, Xinkai; Li, Guangwei; Liang, Wanguo
2015-08-01
Periodically poled crystals are widely used as SHG, DFG, SFG, OPO and THz generation, and there is a broad application prospect in some areas such as the laser display, optical fiber communication, atmospheric exploration and military confrontation. At present, to get the parameters of periodically poled crystals, like duty ratio, the main method is chemical etching of the samples. In this paper, we present a nondestructive characterization system of periodically poled crystals. When we apply a proper high voltage on both sides of the periodically poled crystal, the refractive index difference of positive and negative domain will be increased and we can observe a clear domain pattern by the a microscope so as to obtain general information. Then a single frequency laser is prepared to radiate on +z surface of the periodically poled crystal, we can get some orders of diffraction according to diffraction optics principle. Finally, we can measure the parameters such as period, duty ratio by use of numerical analysis. The testing sample size of this system can be up to 60mm, The accuracy of the testing period can be 0.1?m, and the measurement range of duty ratio is 20%-50%.
Periodic solutions and flip bifurcation in a linear impulsive system
International Nuclear Information System (INIS)
In this paper, the dynamical behaviour of a linear impulsive system is discussed both theoretically and numerically. The existence and the stability of period-one solution are discussed by using a discrete map. The conditions of existence for flip bifurcation are derived by using the centre manifold theorem and bifurcation theorem. The bifurcation analysis shows that chaotic solutions appear via a cascade of period-doubling in some interval of parameters. Moreover, the periodic solutions, the bifurcation diagram, and the chaotic attractor, which show their consistence with the theoretical analyses, are given in an example. (general)
Direct energy recovery system using periodic focusing without grids
International Nuclear Information System (INIS)
Results from a computational study of the efficiency of a direct energy recovery system are presented. This system is similar to R.F. Post's original (gridless) periodic-focus system. However, the computer code used here allows more flexibility than that used by Post. His code requires analytic expressions for the potentials; this code requires only the values of potential on the boundaries. Consequently, the code can be applied to systems where analytic expressions have not been written for the potential. The incident beam used in this study had an average thickness of 0.42 m (as might be expected in an ideal reactor situation) and a maximum divergence angle of +-3.30. Each of the systems tested, when operating at optimum efficiency, recovered 80 percent of the energy, as compared to 91 percent for Post's gridded periodic system
Development of Seismic Isolation Systems Using Periodic Materials
Energy Technology Data Exchange (ETDEWEB)
Yan, Yiqun [Univ. of Houston, Houston, TX (United States); Mo, Yi-Lung [Univ. of Houston, Houston, TX (United States); Menq, Farn-Yuh [Univ. of Texas, Austin, TX (United States); Stokoe, II, Kenneth H. [Univ. of Texas, Austin, TX (United States); Perkins, Judy [Prairie View A & M University, Prairie View, TX (United States); Tang, Yu [Argonne National Lab. (ANL), Argonne, IL (United States)
2014-12-10
Advanced fast nuclear power plants and small modular fast reactors are composed of thin-walled structures such as pipes; as a result, they do not have sufficient inherent strength to resist seismic loads. Seismic isolation, therefore, is an effective solution for mitigating earthquake hazards for these types of structures. Base isolation, on which numerous studies have been conducted, is a well-defined structure protection system against earthquakes. In conventional isolators, such as high-damping rubber bearings, lead-rubber bearings, and friction pendulum bearings, large relative displacements occur between upper structures and foundations. Only isolation in a horizontal direction is provided; these features are not desirable for the piping systems. The concept of periodic materials, based on the theory of solid-state physics, can be applied to earthquake engineering. The periodic material is a material that possesses distinct characteristics that prevent waves with certain frequencies from being transmitted through it; therefore, this material can be used in structural foundations to block unwanted seismic waves with certain frequencies. The frequency band of periodic material that can filter out waves is called the band gap, and the structural foundation made of periodic material is referred to as the periodic foundation. The design of a nuclear power plant, therefore, can be unified around the desirable feature of a periodic foundation, while the continuous maintenance of the structure is not needed. In this research project, three different types of periodic foundations were studied: one-dimensional, two-dimensional, and three-dimensional. The basic theories of periodic foundations are introduced first to find the band gaps; then the finite element methods are used, to perform parametric analysis, and obtain attenuation zones; finally, experimental programs are conducted, and the test data are analyzed to verify the theory. This procedure shows that the periodic foundation is a promising and effective way to mitigate structural damage caused by earthquake excitation.
Real numbers having ultimately periodic representations in abstract numeration systems
Lecomte, P
2002-01-01
Using a genealogically ordered infinite regular language, we know how to represent an interval of R. Numbers having an ultimately periodic representation play a special role in classical numeration systems. The aim of this paper is to characterize the numbers having an ultimately periodic representation in generalized systems built on a regular language. The syntactical properties of these words are also investigated. Finally, we show the equivalence of the classical "theta"-expansions with our generalized representations in some special case related to a Pisot number "theta".
Continuation of periodic orbits in symmetric Hamiltonian and conservative systems
Galan-Vioque, J.; Almaraz, F. J. M.; Macías, E. F.
2014-12-01
We present and review results on the continuation and bifurcation of periodic solutions in conservative, reversible and Hamiltonian systems in the presence of symmetries. In particular we show how two-point boundary value problem continuation software can be used to compute families of periodic solutions of symmetric Hamiltonian systems. The technique is introduced with a very simple model example (the mathematical pendulum), justified with a theoretical continuation result and then applied to two non trivial examples: the non integrable spring pendulum and the continuation of the figure eight solution of the three body problem.
Periodic inspection for safety of CANDU heat transport piping systems
International Nuclear Information System (INIS)
Periodic inspection of heat transport and emergency core cooling piping systems is intended to maintain an adequate level of safety throughout the life of the plant, and to protect plant personnel and the public from the consequences of a failure and release of fission products. This report outlines a rational approach to the periodic inspection based on a fully probabilistic model. It demonstrates the methodology based on theoretical treatment and experimental data whereby the strength of a pressurized pipe or vessel containing a defect could be evaluated. It also shows how the extension of the defect at various lifetimes could be predicted. These relationships are prerequisite for the probabilistic formulation and analysis for the periodic inspection of piping systems
Population Growth and Periodic Instability of the International System
Piepers, I
2006-01-01
From the perspective developed in this paper, it can be argued that exponential population growth resulted in the exponential decrease of the life-span of consecutive stable periods during the life-span of the European international system (1480-1945). However, it becomes evident as well that population growth as such is not a sufficient condition to generate a punctuated equilibrium dynamic in the war dynamics of the international system: other conditions and factors - and their interplay - 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.
Periodic wavetrains for systems of coupled nonlinear Schrödinger equations
Indian Academy of Sciences (India)
Kwok W Chow; Derek W C Lal
2001-11-01
Exact, periodic wavetrains for systems of coupled nonlinear Schrödinger equations are obtained by the Hirota bilinear method and theta functions identities. Both the bright and dark soliton regimes are treated, and the solutions involve products of elliptic functions. The validity of these solutions is veri?ed independently by a computer algebra software. The long wave limit is studied. Physical implications will be assessed.
On the stability of periodically time-dependent quantum systems
Duclos, Pierre; Soccorsi, Eric; Stovicek, Pavel; Vittot, Michel
2007-01-01
The main motivation of this article is to derive sufficient conditions for dynamical stability of periodically driven quantum systems described by a Hamiltonian H(t), i.e., conditions under which it holds sup_{t in R} | (psi(t),H(t) psi(t)) |
Exploration of economic systems in the transition period
Albu, Lucian-Liviu
1993-01-01
The collapse of former communist regime in Central and Eastern Europe opened the transition period from centrally planned to market oriented economies. Thus, the exploration of economic systems in the special situation of transition has become an interesting research topic. The exposition plan includes: 1) General Remarks; 2) Theoretical and Empirical Premises; 3) Econometric Approach; 4) Proposals for Subsequent Research.
Periodic solutions of a spring-pendulum system.
Broucke, R.; Baxa, P. A.
1973-01-01
A study has been made of a dynamical system composed of a pendulum and a harmonic oscillator, in order to show the remarkable resemblance with many classical celestial mechanics problems, in particular, the restricted three-body problem. It is shown that the well-known investigations of periodic orbits can be applied to the present dynamics problem.
Attractors in Frictional Systems Subjected to Periodic Loads
Andersson, Lars-Erik; Barber, J. R.; Ahn, Y-J
2013-01-01
This paper explores the effect of initial conditions on the behavior of coupled frictional elastic systems subject to periodic loading. Previously, it has been conjectured that the long term response will be independent of initial conditions if all nodes slip at least once during each loading cycle. Here, this conjecture is disproved in the context of a simple two-node system. Counter examples are presented of “unstable” steady-state orbits that repel orbits starting from initial conditions t...
Localization of periodic orbits of polynomial systems by ellipsoidal estimates
Energy Technology Data Exchange (ETDEWEB)
Starkov, Konstantin E. [CITEDI-IPN, Avenue del Parque 1310, Mesa de Otay, Tijuana, BC (Mexico)]. E-mail: konst@citedi.mx; Krishchenko, Alexander P. [Bauman Moscow State Technical University, 2nd Baumanskaya Street, 5, Moscow 105005 (Russian Federation)]. E-mail: apkri@999.ru
2005-02-01
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.
Periodic orbits for an infinite family of classical superintegrable systems
International Nuclear Information System (INIS)
We show that all bounded trajectories in the two-dimensional classical system with the potential V(r,?)=?2r2+(?k2)/(r2cos2k?)+(?k2)/(r2sin2k?) are closed for all integer and rational values of k. The period is T=?/2? and does not depend on k. This agrees with our earlier conjecture suggesting that the quantum version of this system is superintegrable.
Stability Analysis for Multi-Parameter Linear Periodic Systems
DEFF Research Database (Denmark)
Seyranian, A.P.; Solem, Frederik; Pedersen, Pauli
1999-01-01
This paper is devoted to stability analysis of general linear periodic systems depending on real parameters. The Floquet method and perturbation technique are the basis of the development. We start out with the first and higher-order derivatives of the Floquet matrix with respect to problem parameters. Then the behaviour of simple and multiple multipliers of the system with a change of parameters is studied. Weak and strong interactions of multipliers in the complex plane are treated separately....
Generalized H2 Control Synthesis for Periodic Systems
DEFF Research Database (Denmark)
Wisniewski, Rafal; Stoustrup, Jakob
2001-01-01
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......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...
Second-order Green's function perturbation theory for periodic systems
Rusakov, Alexander A
2015-01-01
Despite recent advances, systematic quantitative treatment of the electron correlation problem in extended systems remains a formidable task. Systematically improvable Green's function methods capable of quantitatively describing weak and at least qualitatively strong correlations appear promising candidates for computational treatment of periodic systems. We present a periodic implementation of temperature-dependent self-consistent 2nd-order Green's function method (GF2), where the self-energy is evaluated in the basis of atomic orbitals. Evaluating the real-space self-energy in atomic orbitals and solving the Dyson equation in $\\mathbf{k}$-space are the key components of a computationally feasible algorithm. We apply this technique to the 1D hydrogen lattice - a prototypical crystalline system with a realistic Hamiltonian. By analyzing the behavior of the spectral functions, natural occupations, and self-energies, we claim that GF2 is able to recover metallic, band insulating, and at least qualitatively Mot...
Dynamic steady-state of periodically-driven quantum systems
Yudin, V I; Basalaev, M Yu; Kovalenko, D
2015-01-01
Using the density matrix formalism, we prove an existence theorem of the periodic steady-state for an arbitrary periodically-driven system. This state has the same period as the modulated external influence, and it is realized as an asymptotic solution ($t$$\\to$$+\\infty$) due to relaxation processes. The presented derivation simultaneously contains a simple computational algorithm non-using both Floquet and Fourier theories, i.e. our method automatically guarantees a full account of all frequency components. The description is accompanied by the examples demonstrating a simplicity and high efficiency of our method. In particular, for three-level $\\Lambda$-system we calculate the lineshape and field-induced shift of the dark resonance formed by the field with periodically modulated phase. For two-level atom we obtain the analytical expressions for signal of the direct frequency comb spectroscopy with rectangular light pulses. In this case it was shown the radical dependence of the spectroscopy lineshape on pul...
Periodic orbits of hybrid systems and parameter estimation via AD.
Energy Technology Data Exchange (ETDEWEB)
Guckenheimer, John. (Cornell University); Phipps, Eric Todd; Casey, Richard (INRIA Sophia-Antipolis)
2004-07-01
Rhythmic, periodic processes are ubiquitous in biological systems; for example, the heart beat, walking, circadian rhythms and the menstrual cycle. Modeling these processes with high fidelity as periodic orbits of dynamical systems is challenging because: (1) (most) nonlinear differential equations can only be solved numerically; (2) accurate computation requires solving boundary value problems; (3) many problems and solutions are only piecewise smooth; (4) many problems require solving differential-algebraic equations; (5) sensitivity information for parameter dependence of solutions requires solving variational equations; and (6) truncation errors in numerical integration degrade performance of optimization methods for parameter estimation. In addition, mathematical models of biological processes frequently contain many poorly-known parameters, and the problems associated with this impedes the construction of detailed, high-fidelity models. Modelers are often faced with the difficult problem of using simulations of a nonlinear model, with complex dynamics and many parameters, to match experimental data. Improved computational tools for exploring parameter space and fitting models to data are clearly needed. This paper describes techniques for computing periodic orbits in systems of hybrid differential-algebraic equations and parameter estimation methods for fitting these orbits to data. These techniques make extensive use of automatic differentiation to accurately and efficiently evaluate derivatives for time integration, parameter sensitivities, root finding and optimization. The boundary value problem representing a periodic orbit in a hybrid system of differential algebraic equations is discretized via multiple-shooting using a high-degree Taylor series integration method [GM00, Phi03]. Numerical solutions to the shooting equations are then estimated by a Newton process yielding an approximate periodic orbit. A metric is defined for computing the distance between two given periodic orbits which is then minimized using a trust-region minimization algorithm [DS83] to find optimal fits of the model to a reference orbit [Cas04]. There are two different yet related goals that motivate the algorithmic choices listed above. The first is to provide a simple yet powerful framework for studying periodic motions in mechanical systems. Formulating mechanically correct equations of motion for systems of interconnected rigid bodies, while straightforward, is a time-consuming error prone process. Much of this difficulty stems from computing the acceleration of each rigid body in an inertial reference frame. The acceleration is computed most easily in a redundant set of coordinates giving the spatial positions of each body: since the acceleration is just the second derivative of these positions. Rather than providing explicit formulas for these derivatives, automatic differentiation can be employed to compute these quantities efficiently during the course of a simulation. The feasibility of these ideas was investigated by applying these techniques to the problem of locating stable walking motions for a disc-foot passive walking machine [CGMR01, Gar99, McG91]. The second goal for this work was to investigate the application of smooth optimization methods to periodic orbit parameter estimation problems in neural oscillations. Others [BB93, FUS93, VB99] have favored non-continuous optimization methods such as genetic algorithms, stochastic search methods, simulated annealing and brute-force random searches because of their perceived suitability to the landscape of typical objective functions in parameter space, particularly for multi-compartmental neural models. Here we argue that a carefully formulated optimization problem is amenable to Newton-like methods and has a sufficiently smooth landscape in parameter space that these methods can be an efficient and effective alternative. The plan of this paper is as follows. In Section 1 we provide a definition of hybrid systems that is the basis for modeling systems with discontinuities or
Tandem system for periodic measurement of half value layers
International Nuclear Information System (INIS)
Two commercial ionization chambers, one cylindrical and the other with parallel plates, of the Calibration Laboratory of IPEN, were studied in this work. The great difference in their energy dependence allowed the formation of a Tandem system, which was tested for periodic routine determinations of half value layers in low energy X radiation fields (14 to 21 keV). The obtained results showed the usefulness of this technique. (author)
Vibration isolation of automotive vehicle engine using periodic mounting systems
Asiri, S.
2005-05-01
Customer awareness and sensitivity to noise and vibration levels have been raised through increasing television advertisement, in which the vehicle noise and vibration performance is used as the main market differentiation. This awareness has caused the transportation industry to regard noise and vibration as important criteria for improving market shares. One industry that tends to be in the forefront of the technology to reduce the levels of noise and vibration is the automobile industry. Hence, it is of practical interest to reduce the vibrations induced structural responses. The automotive vehicle engine is the main source of mechanical vibrations of automobiles. The engine is vulnerable to the dynamic action caused by engine disturbance force in various speed ranges. The vibrations of the automotive vehicle engines may cause structural failure, malfunction of other parts, or discomfort to passengers because of high level noise and vibrations. The mounts of the engines act as the transmission paths of the vibrations transmitted from the excitation sources to the body of the vehicle and passengers. Therefore, proper design and control of these mounts are essential to the attenuation of the vibration of platform structures. To improve vibration resistant capacities of engine mounting systems, vibration control techniques may be used. For instance, some passive and semi-active dissipation devices may be installed at mounts to enhance vibration energy absorbing capacity. In the proposed study, a radically different concept is presented whereby periodic mounts are considered because these mounts exhibit unique dynamic characteristics that make them act as mechanical filters for wave propagation. As a result, waves can propagate along the periodic mounts only within specific frequency bands called the "Pass Bands" and wave propagation is completely blocked within other frequency bands called the "Stop Bands". The experimental arrangements, including the design of mounting systems with plain and periodic mounts will be studied first. The dynamic characteristics of such systems will be obtained experimentally in both cases. The tests will be then carried out to study the performance characteristics of periodic mounts with geometrical and/or material periodicity. The effectiveness of the periodicity on the vibration levels of mounting systems will be demonstrated theoretically and experimentally. Finally, the experimental results will be compared with the theoretical predictions.
Stability Analysis for Multi-Parameter Linear Periodic Systems
DEFF Research Database (Denmark)
Seyranian, A.P.; Solem, Frederik
1999-01-01
This paper is devoted to stability analysis of general linear periodic systems depending on real parameters. The Floquet method and perturbation technique are the basis of the development. We start out with the first and higher-order derivatives of the Floquet matrix with respect to problem parameters. Then the behaviour of simple and multiple multipliers of the system with a change of parameters is studied. Weak and strong interactions of multipliers in the complex plane are treated separately. The presented theory is exemplified and discussed.
Constraint Based Computation of Periodic Orbits of Chaotic Dynamical Systems
Goldsztejn, Alexandre; Granvilliers, Laurent; Jermann, Christophe
2013-01-01
The chaos theory emerged at the end of the 19th century, and it has given birth to a deep mathematical theory in the 20th century, with a strong practical impact (e.g., weather forecast, turbulence analysis). Periodic orbits play a key role in understanding chaotic systems. Their rigorous computation provides some insights on the chaotic behavior of the system and it enables computer assisted proofs of chaos related properties (e.g., topological entropy). In this paper, we show that the (nume...
Periodically driven ergodic and many-body localized quantum systems
International Nuclear Information System (INIS)
We study dynamics of isolated quantum many-body systems whose Hamiltonian is switched between two different operators periodically in time. The eigenvalue problem of the associated Floquet operator maps onto an effective hopping problem. Using the effective model, we establish conditions on the spectral properties of the two Hamiltonians for the system to localize in energy space. We find that ergodic systems always delocalize in energy space and heat up to infinite temperature, for both local and global driving. In contrast, many-body localized systems with quenched disorder remain localized at finite energy. We support our conclusions by numerical simulations of disordered spin chains. We argue that our results hold for general driving protocols, and discuss their experimental implications
Period-doubling universality in multidimensional dissipative and conservative systems
Ketoja, J. A.
1987-09-01
The standard renormalization theories of dissipative and conservative dynamical systems do not explain all of the observed universal features of two dimensional maps, for example the universal crossover of the Feigenbaum constants before the period-doubling accumulation line. The universal crossover has a counterpart on the other side of the period-doubling accumulation line: universal effective values of the Jacobian control the crossings of the MSS windows away from the strictly one dimensional dissipative limit. All this suggests that there should exist a general renormalization scheme which incorporates a Jacobian as a special parameter and applies everywhere from dissipative to conservative maps. A straightforward generalization of the ideas current in one dimension leads to a candidate for such a generalized theory.
Periodic dynamic systems for infected hosts and mosquitoes
Directory of Open Access Journals (Sweden)
Oliva W. M.
1996-01-01
Full Text Available A mathematical model for the purpose of analysing the dynamic of the populations of infected hosts anf infected mosquitoes when the populations of mosquitoes are periodic in time is here presented. By the computation of a parameter lambda (the spectral radius of a certain monodromy matrix one can state that either the infection peters out naturally (lambda 1 the infection becomes endemic. The model generalizes previous models for malaria by considering the case of periodic coefficients; it is also a variation of that for gonorrhea. The main motivation for the consideration of this present model was the recent studies on mosquitoes at an experimental rice irrigation system, in the South-Eastern region of Brazil.
Eigenvalues, eigenfunctions, and surface states in finite periodic systems
International Nuclear Information System (INIS)
Using a simple approach that requires neither the Bloch functions nor the reciprocal lattice, new, compact, and rigorous analytical formulas are derived for an accurate evaluation of resonant energies, resonant states, energy eigenvalues and eigenfunctions of open and bounded n-cell periodic systems with arbitrary 1D potential shapes, provided the single cell transfer matrix is given. These formulas are applied to obtain the energy spectra and wave functions of a number of simple but representative open and bounded superlattices. We solve the fine structure in bands and exhibit unambiguously that the true eigenfunctions do no not fulfill the periodicity property vertical bar ??,? (z + l c)vertical bar 2 = vertical bar ? ?,? (z)vertical bar 2, with l c the single cell length. We show that the well known surface states and surface energy levels come out naturally. We analyze the surface repulsion effect and calculate exactly the surface energy levels for different potential discontinuities an the ends
ECONOMIC AND FINANCIAL PERIODS INDUCED THROUGH BANKING SYSTEM
Directory of Open Access Journals (Sweden)
Ionita Rodica -Oana
2013-07-01
Full Text Available Abstract:This paper is an empirical study which analyzes the influence of banking system to the economic and financial environment. At the basis of this research there are two subjective definitions of economic instability periods (CII and of financial instability periods (FII and two composite indexes called EWI (Economic Warning Index and FWI (Financial Warning Index defined in a prior research. Because it is not possible to predict the exact point in time at which the crisis sets in, the purpose of this paper is to identify possible vulnerabilities induced through banking system and to treat them in order to mitigate the costs of the economy. I defined a set of eighteen potential leading indicators from banking/financial sector, in the period 2000 - 2012. The countries included in the study are Czech Republic, Hungary and Romania. It was composed a balance panel with seven hundred and eighty observations. There is both a quantitative and qualitative approach. Using econometrics technicques as OLS regressions, Fixed effects and Fixed dummy effects there were identfied significant banking indicators in explaining economic and financial instability periods. Then, I compose a banking index which captures the costs occurred to the banking system and I assess its performance in explaining the economic and financial instability indexes through in the sample and out of the sample techniques. At the basis of my decision to choose a continuous model was the fact that it motivates policy makers in steering policy continuously and the fact that there is no need to decide between yes/ no value of crisis. This research aim to observe the influence of the banking sector evolution to the incidence of economic and financial instability periods and give us a warning regardless any negative trends in the macroeconomic or financial activity, affecting the national or the global situation. Using model simulations on historical data, the model performance was assessed upon in the sample and out of sample estimation techniques. The evaluation results suggest that banking indicators give us a warning signal of the negative trend of economic and financial environment.
Resonant transmission through a multiple periodic scattering system
International Nuclear Information System (INIS)
We investigate the propagation and transmission of electromagnetic (EM) waves in the subwavelength regime when a multiple periodic scattering system (MPSS) is illuminated by a monochromatic plane wave. This system has a cascaded structure with square hole arrays periodically perforated on a metal slab with arbitrary slab thickness and arbitrary air-gap. The framework of this paper is based on a modal expansion theory, in which the EM fields in pure vacuum are expanded in terms of plane waves, while those in the holes of the slab are expressed in terms of waveguide modes. The boundary conditions for the EM waves lead to a system of equations whose solution can be obtained quasianalytically in a monomodal approximation method. We study the transmission spectrum and field distribution in the MPSS, varying geometrical parameters such as the air-gap and/or number N of slabs in the context of symmetrical and asymmetrical geometries. We find that an MPSS with N ? 2 provides discrete transmission windows whose resonance order linearly increases against N and the associated resonance wavelengths are confined to a specific finite band for large N. The EM fields at the resonance states are quite uniquely distributed in the MPSS, depending not only on the resonance wavelength, but also either on even N or on odd N. We also demonstrate that the transmission of the EM energy is strongly boosted by the evanescent electric fields mirror-symmetrically distributed in the air-gaps of the MPSS. (paper)
Semiclassical quantization of nonadiabatic systems with hopping periodic orbits
Energy Technology Data Exchange (ETDEWEB)
Fujii, Mikiya, E-mail: mikiya.fujii@gmail.com; Yamashita, Koichi [Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Tokyo 113-8656 (Japan); JST, CREST, Tokyo 113-8656 (Japan)
2015-02-21
We present a semiclassical quantization condition, i.e., quantum–classical correspondence, for steady states of nonadiabatic systems consisting of fast and slow degrees of freedom (DOFs) by extending Gutzwiller’s trace formula to a nonadiabatic form. The quantum–classical correspondence indicates that a set of primitive hopping periodic orbits, which are invariant under time evolution in the phase space of the slow DOF, should be quantized. The semiclassical quantization is then applied to a simple nonadiabatic model and accurately reproduces exact quantum energy levels. In addition to the semiclassical quantization condition, we also discuss chaotic dynamics involved in the classical limit of nonadiabatic dynamics.
Stability analysis of periodically switched linear systems using Floquet theory
Directory of Open Access Journals (Sweden)
Gökçek Cevat
2004-01-01
Full Text Available Stability of a switched system that consists of a set of linear time invariant subsystems and a periodic switching rule is investigated. Based on the Floquet theory, necessary and sufficient conditions are given for exponential stability. It is shown that there exists a slow switching rule that achieves exponential stability if at least one of these subsystems is asymptotically stable. It is also shown that there exists a fast switching rule that achieves exponential stability if the average of these subsystems is asymptotically stable. The results are illustrated by examples.
Semiclassical quantization of nonadiabatic systems with hopping periodic orbits
International Nuclear Information System (INIS)
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
Robust detection of periodic time series measured from biological systems
Directory of Open Access Journals (Sweden)
Huttunen Heikki
2005-05-01
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/.
Directory of Open Access Journals (Sweden)
Khazan A.
2011-01-01
Full Text Available In the earlier study (Khazan A. Upper Limit in Mendeleev's Periodic Table - Element No.155. 2nd ed., Svenska fysikarkivet, Stockholm, 2010 the author showed how Rhodium can be applied to the hyperbolic law of the Periodic Table of Elements in order to calculate, with high precision, all other elements conceivable in the Table. Here we obtain the same result, with use of fraction linear functions (adjacent hyperbolas.
Statistics of work distribution in periodically driven closed quantum systems.
Dutta, Anirban; Das, Arnab; Sengupta, K
2015-07-01
We study the statistics of the work distribution P(w) in a d-dimensional closed quantum system with linear dimension L subjected to a periodic drive with frequency ?(0). We show that the corresponding rate function I(w)=-ln[P(w)/?(0)]/L^{d} after a drive period satisfies a universal lower bound I(0)?n(d) and has a zero at w=QL(d)/N, where n(d) and Q are the excitation and the residual energy densities generated during the drive, ?(0) is a constant fixed by the normalization of P(w), and N is the total number of constituent particles or spins in the system. We supplement our results by calculating I(w) for a class of d-dimensional integrable models and show that I(w) has an oscillatory dependence on ?(0) originating from Stuckelberg interference generated due to double passage through the critical point or region during the drive. We suggest experiments to test our theory. PMID:26274122
Optimal stabilization of unstable periodic orbits embedded in chaotic systems
Scientific Electronic Library Online (English)
C.A., Cruz-Villar.
2007-10-01
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.
On resumming periodic orbits in the spectra of integrable systems
International Nuclear Information System (INIS)
Spectral determinants have proved to be valuable tools for resumming the periodic orbits in the Gutzwiller trace formula of chaotic systems. We investigate these tools in the context of integrable systems to which these techniques have not been previously applied. Our specific model is a stroboscopic map of an integrable Hamiltonian system with quadratic action dependence, for which each stage of the semiclassical approximation can be controlled. It is found that large errors occur in the semiclassical traces due to edge corrections which may be neglected if the eigenvalues are obtained by Fourier transformation over the long time dynamics. However, these errors cause serious harm to the spectral approximations of an integrable system obtained via the spectral determinants. The symmetry property of the spectral determinant does not generally alleviate the error, since it sometimes sheds a pair of eigenvalues from the unit circle. By taking into account the leading-order asymptotics of the edge corrections, the spectral determinant method makes a significant recovery
Benner, Peter; Hossain, Mohammad-Sahadet; Stykel, Tatjana
2012-01-01
We discuss the numerical solution of large-scale sparse projected discrete-time periodic Lyapunov equations in lifted form which arise in model reduction of periodic descriptor systems. We extend the alternating direction implicit method and the Smith method to such equations. Low-rank versions of these methods are also presented, which can be used to compute low-rank approximations to the solutions of projected periodic Lyapunov equations in lifted form with low-rank right-hand side. Moreove...
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
On the stability of periodically time-dependent quantum systems
Duclos, Pierre; Stovicek, Pavel; Vittot, Michel
2007-01-01
The main motivation of this article is to derive sufficient conditions for dynamical stability of periodically driven quantum systems described by a Hamiltonian H(t), i.e., conditions under which it holds sup_{t in R} | (psi(t),H(t) psi(t)) |<\\infty where psi(t) denotes a trajectory at time t of the quantum system under consideration. We start from an analysis of the domain of the quasi-energy operator. Next we show, under certain assumptions, that if the spectrum of the monodromy operator U(T,0) is pure point then there exists a dense subspace of initial conditions for which the mean value of energy is uniformly bounded in the course of time. Further we show that if the propagator admits a differentiable Floquet decomposition then || H(t) psi(t) || is bounded in time for any initial condition psi(0), and one employs the quantum KAM algorithm to prove the existence of this type of decomposition for a fairly large class of H(t). In addition, we derive bounds uniform in time on transition probabilities betwe...
Nam, Seung-Il; Woo, Kyung Sik; Ji, Hyo Seon; Stein, Ruediger; Mackensen, Andreas; Matthiessen, Jens
2015-04-01
Authigenic carbonates and mud fractions of the glaciomarine sediments were investigated texturally and geochemically. The sediment core (PS72/410-1) was retrieved using a giant box corer from the central Mendeleev Ridge of the western Arctic Ocean (Station location= Lat. 80°30.37"N, Long. 175°44.38"W) during the Polarstern Arctic expedition (PS72) in 2008. The core is 39 cm long with age of ca. 76 ka BP and was collected from the water depth of 1,802 meters. The sediments show various colours from grey to brown as previously reported in other Arctic deep sea sediments, reflecting glacial-interglacial and/or stadial-interstadial cycles. Authigenic carbonate minerals are present through the whole sequence except for a few centimetres. These authigenic carbonates are composed of high Mg-calcite, low Mg-calcite and aragonite. Various crystal shapes of aragonite and calcite together with clear growth shapes of the crystals suggest that they are inorganic in origin. Highly enriched carbon isotope compositions (?13C = 0 ~ +5‰ vs. PDB) strongly indicate that they formed in methanogenic zone below sediment/water interface by the reaction between anoxic pore fluids and host sediments induced by methanogenic bacteria. However, a wide range of oxygen isotope values (?18O = -5 ~ +5‰ vs. PDB) may indicate that porewater has been changed due to reaction between residual seawater and volcanic sediments. Relatively higher contents of K, Al, Fe and Be values from muddy sediments as well as low ?18O compositions of authigenic carbonates may imply strong input of meltwater from volcanic region (Eastern Arctic region) whereas higher oxygen isotope compositions of authigenic carbonates and higher Sr and K contents of mud sediments may reflect stronger influence from carbonate-rich region (Canadian Arctic region). Mineralogical changes form low to high Mg-calcite together with decrease in Mg, Sr and Fe contents strongly support less freshwater input from glacial mode to interglacial mode. Based on the stable isotope data of authigenic carbonates and trace element contents of mud sediments, formation history of the Upper Deep Polar Water can be reconstructed.
Woo, K. S.; Ji, H. S.; Nam, S.; Stein, R. H.; Mackensen, A.; Matthiessen, J. J.
2013-12-01
Carbonate minerals were discovered from the giant box core (PS72/410-1) of the pelagic sediments recovered from the Canadian Arctic across the central Mendeleev Ridge (Station location= Lat. 80°30.37"N, Long. 175°44.38"W) during the Arctic cruise by Polarstern in 2008. The core was 39 cm long and was collected from the water depth of 1802 meters. The sediments show various colours from grey to brown as previously reported in other Arctic pelagic sediments. The sediments include planktonic foraminifers together with carbonate minerals. The contents of planktonic foraminifers and carbonate minerals vary with core depth, however these carbonate minerals are present through the whole sequence except for a few centimetres. After wet sieving, coarse fractions were texturally examined with binocular microscope and SEM, and stable isotope and trace element contents were obtained. Mineralogy of carbonate minerals were determined using crystal shapes and qualitative Sr contents by EDAX together with trace element analysis. The carbonates are composed of high Mg-calcite, low Mg-calcite and aragonite. Aragonite crystals show (1) radiating fibrous texture, (2) randomly oriented fibrous texture, (3) spherulitic fibrous texture, and (4) bladed texture, and calcite crystals show (1) foliated texture, (2) randomly bladed texture, (3) spherulitic fibrous texture, and (4) equant texture. Various crystal shapes of aragonite and calcite together with clear growth shapes of the crystals suggest that they are inorganic in origin. Highly enriched carbon isotope compositions (?13C = 0 ~ +5‰ vs. PDB) strongly indicate that they formed in methanogenic zone below sediment/water interface by the reaction between anoxic pore fluids and host sediments induced by methanogenic bacteria. However, a wide range of oxygen isotope values (?18O = -5 ~ +5‰ vs. PDB) may indicate that porewater has been changed due to reaction between residual seawater and volcanic sediments. Four types of stable isotope compositions are recognized and they imply complicated evolution of early diagenetic pore waters. Because the core sediments are not organic-rich, the presence of the authigenic carbonates may be related to paleoceanograhic conditions of the Arctic Ocean which resulted in anoxic pore water conditions just a few centimetres below the sediment/water interface. Trace elemental compositions show clear divisions at the boundary of ca. 10 cm in core depth. Carbonates found shallower than this depth show higher Mg, Mn, Fe and Sr compositions which may imply paleoenvironmental changes with time.
International Nuclear Information System (INIS)
The 4 volume of the XVIII Mendeleev congress on general and applied chemistry includes summaries of reports, lectures and stand information on achievements and prospects of chemical science in such areas as methods and devices for chemical investigations and analysis, education, high energy chemistry, biomolecular chemistry and biotechnology
A note on discrete-time dynamical systems under periodic perturbation
Directory of Open Access Journals (Sweden)
Xiaosong Yang
2006-07-01
Full Text Available We present some results on the existence and the minimum period of periodic orbits for discrete-time dynamical systems under periodic perturbation. Some examples are presented to illustrate these results.
From chaotic to disordered systems - a periodic orbit approach
Dahlqvist, Per
1998-01-01
We apply periodic orbit theory to a quantum billiard on a torus with a variable number N of small circular scatterers distributed randomly. Provided these scatterers are much smaller than the wave length they may be regarded as sources of diffraction. The relevant part of the spectral determinant is due to diffractive periodic orbits only. We formulate this diffractive zeta function in terms of a N*N transfer matrix, which is transformed to real form. The zeros of this deter...
Emergence of spike correlations in periodically forced excitable systems
Reinoso, Jose A; Masoller, Cristina
2015-01-01
In sensory neurons the presence of noise can facilitate the detection of weak information-carrying signals, which are encoded and transmitted via correlated sequences of spikes. Here we investigate relative temporal order in spike sequences induced by a subthreshold periodic input, in the presence of white Gaussian noise. To simulate the spikes, we use the FitzHugh-Nagumo model, and to investigate the output sequence of inter-spike intervals (ISIs), we use the symbolic method of ordinal analysis. We find different types of relative temporal order, in the form of preferred ordinal patterns which depend on both, the strength of the noise and the period of the input signal. We also demonstrate a resonance-like behavior, as certain periods and noise levels enhance temporal ordering in the ISI sequence, maximizing the probability of the preferred patterns. Our findings could be relevant for understanding the mechanisms underlying temporal coding, by which single sensory neurons represent in spike sequences the inf...
Directory of Open Access Journals (Sweden)
Vyatkin V. B.
2013-05-01
Full Text Available In the article, for the first time we have considered group of electrons radial to atomic nucleus with equal value of orbital quantum number and equal sequence of emergence on subshells. As a result of this consideration, the exclusion orbital principle which regulates distribution of electrons in atom on values of spin has been established. On the basis of this principle, the orbital system of distribution of electrons which adequately corresponds to the valid system installed according to the spectral analysis is developed. From positions of orbital system the new explanation of reasons for deviation of the valid system of distribution of electrons in atom from ideal system of consecutive filling of electron shells has been offered and the nature of the empirical rule is opened. The structure of periodic system is also considered and the explanation of the reasons pair repetition of the periods on number of elements is offered. It is thus shown that borders of the chemical periods are displaced relatively borders of the periods of orbital system on two elements to the left
Gravitational waves from periodic three-body systems.
Dmitrašinovi?, V; Suvakov, Milovan; Hudomal, Ana
2014-09-01
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
International Nuclear Information System (INIS)
The abstracts of the XIX Mendeleev Congress on general and applied chemistry held 25-30 September 2011 in Volgograd are presented. The program includes the Congress plenary and section reports, poster presentations, symposia and round tables on key areas of chemical science and technology, and chemical education. The work of the Congress was held the following sections: 1. Fundamental problems of chemical sciences; 2. Chemistry and technology of materials, including nanomaterials; 3. Physicochemical basis of metallurgical processes; 4. Current issues of chemical production, technical risk assessment; 5. Chemical aspects of modern power and alternative energy sources; 6. Chemistry of fossil and renewable hydrocarbons; 7. Analytical chemistry: new methods and instruments for chemical research and analysis; 8. Chemical education. Volume 2 includes abstracts of oral and poster presentations of the section Chemistry and technology of materials, including nanomaterials, and author index
Emergence of quasiperiodicity in symmetrically coupled, identical period-doubling systems
DEFF Research Database (Denmark)
Reick, Christian; Mosekilde, Erik
1995-01-01
When two Identical period-doubling systems are coupled symmetrically, the period-doubling transition to chaos may be replaced by a quasiperiodic transition. The reason for this is that at an early stage of the period-doubling cascade, a Hopf bifurcation instead of a period-doubling bifurcation occurs. Our main result is that the emergence of this Hopf bifurcation is a generic phenomenon in symmetrically coupled, identical period-doubling systems. The whole phenomenon is stable against small nons...
Dynamical System Approach to a Coupled Dispersionless System: Localized and Periodic Traveling Waves
International Nuclear Information System (INIS)
We investigate the dynamical behavior of a coupled dispersionless system describing a current-conducting string with infinite length within a magnetic field. Thus, following a dynamical system approach, we unwrap typical miscellaneous traveling waves including localized and periodic ones. Studying the relative stabilities of such structures through their energy densities, we find that under some boundary conditions, localized waves moving in positive directions are more stable than periodic waves which in contrast stand for the most stable traveling waves in another boundary condition situation. (general)
Branching of periodic orbits in reversible hamiltonian systems
Buzzi, Claudio; Teixeira, Marco Antonio
2010-01-01
This paper deals with the dynamics of time-reversible Hamiltonian vector fields with 2 and 3 degrees of freedom around an elliptic equilibrium point in presence of symplectic involutions. The main results discuss the existence of one-parameter families of reversible periodic solutions terminating at the equilibrium. The main techniques used are Birkhoff and Belitskii normal forms combined with the Liapunov-Schmidt reduction.
Chaos in periodically forced Holling type II predator-prey system with impulsive perturbations
Energy Technology Data Exchange (ETDEWEB)
Zhang Shuwen [Institute of Biomathematics, Anshan Normal University, Liaoning, Anshan 114005 (China)] e-mail: anzsw_123@163.com; Tan Dejun [Institute of Biomathematics, Anshan Normal University, Liaoning, Anshan 114005 (China)] e-mail: tdj650314@163.com; Chen Lansun [Department of Applied Mathematics, Dalian University of Technology, Liaoning, Dalian 116024 (China)] e-mail: lschen@math08.math.ac.cn
2006-04-01
The effect of periodic forcing and impulsive perturbations on predator-prey model with Holling type II functional response is investigated. The periodic forcing is affected by assuming a periodic variation in the intrinsic growth rate of prey. The impulsive perturbation is affected by introducing periodic constant impulsive immigration of predator. The dynamical behavior of the system is simulated and bifurcation diagrams are obtained for different parameters. The results show that periodic forcing and impulsive perturbation can very easily give rise to complex dynamics, including (1) quasi-periodic oscillating, (2) period doubling cascade, (3) chaos, (4) period halfing cascade, (5) non-unique dynamics.
Chaos in periodically forced Holling type IV predator-prey system with impulsive perturbations
Energy Technology Data Exchange (ETDEWEB)
Zhang Shuwen [Institute of Biomathematics, Anshan Normal University, Liaoning, Anshan 114005 (China)] e-mail: anzsw_123@163.com; Tan Dejun [Institute of Biomathematics, Anshan Normal University, Liaoning, Anshan 114005 (China)] e-mail: tdj650314@163.com; Chen Lansun [Department of Applied Mathematics, Dalian University of Technology, Liaoning, Dalian 116024 (China)] e-mail: lschen@math08.math.ac.cn
2006-02-01
The effect of periodic forcing and impulsive perturbations on predator-prey model with Holling type IV functional response is investigated. The periodic forcing is affected by assuming a periodic variation in the intrinsic growth rate of the prey. The impulsive perturbations are affected by introducing periodic constant impulsive immigration of predator. The dynamical behavior of the system is simulated and bifurcation diagrams are obtained for different parameters. The results show that periodic forcing and impulsive perturbation can easily give rise to complex dynamics, including (1) quasi-periodic oscillating, (2) period doubling cascade, (3) chaos, (4) period halfing cascade.
Traveling pulse on a periodic background in parametrically driven systems.
León, Alejandro O; Clerc, Marcel G; Coulibaly, Saliya
2015-05-01
Macroscopic systems with dissipation and time-modulated injection of energy, parametrically driven systems, can self-organize into localized states and/or patterns. We investigate a pulse that travels over a one-dimensional pattern in parametrically driven systems. Based on a minimal prototype model, we show that the pulses emerge through a subcritical Andronov-Hopf bifurcation of the underlying pattern. We describe a simple physical system, a magnetic wire forced with a transverse oscillatory magnetic field, which displays these traveling pulses. PMID:26066109
Quantum System under Periodic Perturbation Effect of Environment
Hotta, M; Matsumoto, S; Yoshimura, M; Matsumoto, Sh.
1996-01-01
In many physical situations the behavior of a quantum system is affected by interaction with a larger environment. We develop, using the method of influence functional, how to deduce the density matrix of the quantum system incorporating the effect of environment. After introducing characterization of the environment by spectral weight, we first devise schemes to approximate the spectral weight, and then a perturbation method in field theory models, in order to approximately describe the environment. All of these approximate models may be classified as extended Ohmic models of dissipation whose differences are in the high frequency part. The quantum system we deal with in the present work is a general class of harmonic oscillators with arbitrary time dependent frequency. The late time behavior of the system is well described by an approximation that employs a localized friction in the dissipative part of the correlation function appearing in the influence functional. The density matrix of the quantum system i...
Genesis of the anti-plague system: the Tsarist period.
Melikishvili, Alexander
2006-01-01
Although the anti-plague system of the former Soviet Union developed fully during the Soviet era, its foundations were laid long before the Bolshevik Revolution of 1917. This article traces the evolution of the anti-plague measures from imposition of temporary quarantine in affected areas to the creation of the standard response system and the establishment of permanent anti-plague organizations. The purpose of this article is to demonstrate that by the end of the nineteenth century and the beginning of the twentieth century, despite numerous setbacks, the Russian imperial authorities succeeded in creating a nascent system of disease surveillance dedicated to protecting the population from especially dangerous infectious diseases such as plague. PMID:16610335
Heavy water system management during Cirus refurbishing period
International Nuclear Information System (INIS)
During refurbishing of Cirus, total system heavy water inventory is stored in storage tank under helium atmosphere. Reactor vessel is kept isolated from rest of the system with continuous helium purging. Main gas holder rides on system. About 4.3 ton of chloride-laden heavy water and 105 kg of oil contaminated heavy water having iron content got accumulated in Cirus. Chloride laden heavy water was treated using a mixed bed ion exchange column. Oil contaminated heavy water was treated with activated charcoal powder and then passed through ion exchange column. Purified heavy water will be upgraded to more than 99.81 % w/w in Heavy Water Division and brought back to Cirus for use before commissioning the reactor. (author)
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.)
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. (author)
The European debate on rate systems in the interwar period
Energy Technology Data Exchange (ETDEWEB)
Madureira, Nuno Luis [ISCTE cacifo 321B, Av Forcas Armadas, 1600 Lisboa (Portugal)
2010-08-15
This article describes a particular branch that evolved in the diffusion of electrical rate systems in twentieth-century Europe and the debate that ensued between the competitive, promotional and cost based approaches. Three major questions are addressed: What factors and historical circumstances favoured the emergence of more or less efficient pricing schemes? Why did some enterprises opt for promotional rates while others defended the cost based alternative? What is the historical origin of marginal cost pricing? It is shown how the volatility of the costs that characterize hydro-electric production made this particular technology very sensitive to a cost approach towards pricing and to a seasonal and time-of-day perspective on rate systems. (author)
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.
Quantum mechanics of rapidly and periodically driven systems
Indian Academy of Sciences (India)
Malay Bandyopadhyay; Sushanta Dattagupta
2008-03-01
This review deals with the dynamics of quantum systems that are subject to high frequency external perturbations. Though the problem may look hopelessly time-dependent, and poised on the extreme opposite side of adiabaticity, there exists a `Kapitza Window' over which the dynamics can be treated in terms of effective time-independent Hamiltonians. The consequent results are important in the context of atomic traps as well as quantum optic properties of atoms in intense and high-frequency electromagnetic fields.
Periodic inspection for safety of CANDU heat transport piping systems
International Nuclear Information System (INIS)
An approach has been developed for the prediction of the risk of failure or the survival of heat transport piping systems in a nuclear power plant. The effects of various inspection schemes on the risk of failure have been investigated and an inspection method proposed. A list of input data required to apply this method to real situations is specified. Using an example of a pressurized pipe containing a defect, it is shown that the required data can be obtained easily
Optimal maintenance policy for a Markovian system under periodic inspection
International Nuclear Information System (INIS)
This study proposes a state-dependent maintenance policy Ri,j(T,N,?) for a multi-state continuous-time Markovian deteriorating system subject to aging and fatal shocks and with states 0 (new state) i,j(T,N,?), the system is inspected at each kT for k=1,2,3... to identify the current state as, say a, and then do-nothing, repair and replacement are taken immediately according to 0?a?i-1, i?a?j-1 and j?a?L-1, respectively in case i< j. Additionally, the replacement is carried out whenever L occurs due to fatal shocks. This policy includes numerous maintenance policies in the literature as special cases and can be applied quite generally. We then try to determine the optimal i*, j* and T* such that the expected long-run cost rate is minimized. A numerical example is given to evaluate the performance of the policy
Shimeld, John; Li, Qingmou; Chian, Deping; Lebedeva-Ivanova, Nina; Jackson, Ruth; Mosher, David; Hutchinson, Deborah
2016-01-01
The Canada Basin and the southern Alpha-Mendeleev ridge complex underlie a significant proportion of the Arctic Ocean, but the geology of this undrilled and mostly ice-covered frontier is poorly known. New information is encoded in seismic wide-angle reflections and refractions recorded with expendable sonobuoys between 2007 and 2011. Velocity-depth samples within the sedimentary succession are extracted from published analyses for 142 of these records obtained at irregularly spaced stations across an area of 1.9E + 06 km2. The samples are modelled at regional, subregional and station-specific scales using an exponential function of inverse velocity versus depth with regionally representative parameters determined through numerical regression. With this approach, smooth, non-oscillatory velocity-depth profiles can be generated for any desired location in the study area, even where the measurement density is low. Practical application is demonstrated with a map of sedimentary thickness, derived from seismic reflection horizons interpreted in the time domain and depth converted using the velocity-depth profiles for each seismic trace. A thickness of 12-13 km is present beneath both the upper Mackenzie fan and the middle slope off of Alaska, but the sedimentary prism thins more gradually outboard of the latter region. Mapping of the observed-to-predicted velocities reveals coherent geospatial trends associated with five subregions: the Mackenzie fan; the continental slopes beyond the Mackenzie fan; the abyssal plain; the southwestern Canada Basin; and, the Alpha-Mendeleev magnetic domain. Comparison of the subregional velocity-depth models with published borehole data, and interpretation of the station-specific best-fitting model parameters, suggests that sandstone is not a predominant lithology in any of the five subregions. However, the bulk sand-to-shale ratio likely increases towards the Mackenzie fan, and the model for this subregion compares favourably with borehole data for Miocene turbidites in the eastern Gulf of Mexico. The station-specific results also indicate that Quaternary sediments coarsen towards the Beaufort-Mackenzie and Banks Island margins in a manner that is consistent with the variable history of Laurentide Ice Sheet advance documented for these margins. Lithological factors do not fully account for the elevated velocity-depth trends that are associated with the southwestern Canada Basin and the Alpha-Mendeleev magnetic domain. Accelerated porosity reduction due to elevated palaeo-heat flow is inferred for these regions, which may be related to the underlying crustal types or possibly volcanic intrusion of the sedimentary succession. Beyond exploring the variation of an important physical property in the Arctic Ocean basin, this study provides comparative reference for global studies of seismic velocity, burial history, sedimentary compaction, seismic inversion and overpressure prediction, particularly in mudrock-dominated successions.
Periodic Flows to Chaos Based on Discrete Implicit Mappings of Continuous Nonlinear Systems
Luo, Albert C. J.
This paper presents a semi-analytical method for periodic flows in continuous nonlinear dynamical systems. For the semi-analytical approach, differential equations of nonlinear dynamical systems are discretized to obtain implicit maps, and a mapping structure based on the implicit maps is employed for a periodic flow. From mapping structures, periodic flows in nonlinear dynamical systems are predicted analytically and the corresponding stability and bifurcations of the periodic flows are determined through the eigenvalue analysis. The periodic flows predicted by the single-step implicit maps are discussed first, and the periodic flows predicted by the multistep implicit maps are also presented. Periodic flows in time-delay nonlinear dynamical systems are discussed by the single-step and multistep implicit maps. The time-delay nodes in discretization of time-delay nonlinear systems were treated by both an interpolation and a direct integration. Based on the discrete nodes of periodic flows in nonlinear dynamical systems with/without time-delay, the discrete Fourier series responses of periodic flows are presented. To demonstrate the methodology, the bifurcation tree of period-1 motion to chaos in a Duffing oscillator is presented as a sampled problem. The method presented in this paper can be applied to nonlinear dynamical systems, which cannot be solved directly by analytical methods.
On the stabilization of periodic orbits for discrete time chaotic systems
International Nuclear Information System (INIS)
In this Letter we consider the stabilization problem of unstable periodic orbits of discrete time chaotic systems. We propose a novel and simple periodic delayed feedback law and present some stability results. These results show that all hyperbolic periodic orbits as well as some non-hyperbolic periodic orbits can be stabilized with the proposed method. The stability proofs also give the possible feedback gains which achieve stabilization. We will also present some simulation results
Stabilization of periodic solutions in a tethered satellite system by damping injection
DEFF Research Database (Denmark)
Larsen, Martin Birkelund; Blanke, Mogens
2009-01-01
A spacecraft with electrodynamic tether orbiting the Earth will be subject to a periodic forcing term induced by the variation of the magnetic field along the orbit. The periodic forcing term leads to a family of unstable periodic solutions for a tether carrying a constant current. This paper presents a control design for stabilizing these periodic solutions. The design consists of a control law for stabilizing the open-loop equilibrium and a bias term which forces the system trajectory away fro...
Stabilization of Periodic Solutions in a Thedered Satellite System by Damping Injection
DEFF Research Database (Denmark)
Larsen, Martin Birkelund; Blanke, Mogens
2009-01-01
A spacecraft with electrodynamic tether orbiting the Earth will be subject to a periodic forcing term induced by the variation of the magnetic field along the orbit. The periodic forcing term leads to a family of unstable periodic solutions for a tether carrying a constant current. This paper presents a control design for stabilizing these periodic solutions. The design consists of a control law for stabilising the open-loo equibrilibrium and a bias term which forces the system trajectory away f...
Gondhalekar, R.; Jones, Colin
2011-01-01
State-feedback model predictive control (MPC) of discrete-time linear periodic systems with time-dependent state and input dimensions is considered. The states and inputs are subject to periodically time-dependent, hard, convex, polyhedral constraints. First, periodic controlled and positively invariant sets are characterized, and a method to determine the maximum periodic controlled and positively invariant sets is derived. The proposed periodic controlled invariant sets are then employed in...
Stochastic long term modelling of a drainage system with estimation of return period uncertainty
DEFF Research Database (Denmark)
Thorndahl, Søren
2009-01-01
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...... 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...
Stochastic Long Term Modelling of a Drainage System with Estimation of Return Period Uncertainty
DEFF Research Database (Denmark)
Thorndahl, Søren
2008-01-01
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...... 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...
Confrontation between Quantized Periods of Some Extra-Solar Planetary Systems and Observations
Morcos, A. B.
2013-01-01
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 p...
The periodic n-species Gilpin-Ayala competition system with impulsive effect
Energy Technology Data Exchange (ETDEWEB)
Zhang Shuwen [Institute of Biomathematics, Anshan Normal University, Anshan, Liaoning 114005 (China)] e-mail: anzsw_123@163.com; Tan Dejun [Institute of Biomathematics, Anshan Normal University, Anshan, Liaoning 114005 (China)] e-mail: Tdj650314@163.com; Chen Lansun [Department of Applied Mathematics, Dalian University of Technology, Dalian, Liaoning 116024 (China)] e-mail: lschen@math08.math.ac.cn
2005-10-01
In this paper, a generalized periodic n-species Gilpin-Ayala competition systems with impulsive effect is investigated. The sufficient conditions are derived for the permanence of the system. We discuss the stabilities of trivial solution and bounded periodic solution. By using the method of coincidence degree, a set of sufficient conditions are derived for the existence of at least one strictly positive componentwise periodic solution, the example shows that our criteria are easily verifiable.
Directory of Open Access Journals (Sweden)
Weibing Wang
2007-09-01
Full Text Available We considered a nonautonomous two dimensional predator-prey system with impulsive effect. Conditions for the permanence of the system and for the existence of a unique stable periodic solution are obtained.
The virial theorem and exact properties of density functionals for periodic systems
Mirhosseini, H; Baldsiefen, T; Sanna, A; Proetto, C R; Gross, E K U
2014-01-01
In the framework of density functional theory, scaling and the virial theorem are essential tools for deriving exact properties of density functionals. Preexisting mathematical difficulties in deriving the virial theorem via scaling for periodic systems are resolved via a particular scaling technique. This methodology is employed to derive universal properties of the exchange-correlation energy functional for periodic systems.
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
Design of real-time periodic control systems through synchronization and fixed priorities
Simon, Daniel; Benattar, Fanny
2005-01-01
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...
Design of real-time periodic control systems through synchronisation and fixed priorities
Simon, Daniel; Benattar, Fanny
2002-01-01
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....
Permanence and Positive Periodic Solutions of a Discrete Delay Competitive System
Zhijun Liu; Wenjie Qin
2010-01-01
A discrete time non-autonomous two-species competitive system with delays is proposed, which involves the influence of many generations on the density of species population. Sufficient conditions for permanence of the system are given. When the system is periodic, by using the continuous theorem of coincidence degree theory and constructing a suitable Lyapunov discrete function, sufficient conditions which guarantee the existence and global attractivity of positive periodic solutions are obta...
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
Stabilization of Periodic Solutions in a Thedered Satellite System by Damping Injection
DEFF Research Database (Denmark)
Larsen, Martin Birkelund; Blanke, Mogens
2009-01-01
A spacecraft with electrodynamic tether orbiting the Earth will be subject to a periodic forcing term induced by the variation of the magnetic field along the orbit. The periodic forcing term leads to a family of unstable periodic solutions for a tether carrying a constant current. This paper presents a control design for stabilizing these periodic solutions. The design consists of a control law for stabilising the open-loo equibrilibrium and a bias term which forces the system trajectory away from the equilibrium. The tether needs to be positioned away from open-loop equilibrium for the tether to affect the orbit parameters. An approximation of the periodic solutions of the closed loop system is found as a series expansion in the parameter plane spanned by the controller gain and the bias term. The stability of the solutions is investigated using linear Floquet analysis of the variational equation and the region of stable periodic solutions in the parameter plane is found.
Comment on ``Periodic wave functions and number of extended states in random dimer systems'
Hilke, M.; J. C. Flores; DomÃnguez-Adame Acosta, Francisco
1997-01-01
In a recent report, Huang, Wu, and Gong [Phys. Rev. B 55, 11018 (1997)] studied numerically the electronic properties of a random dimer model (RDM) and found extended periodic wave functions near the critical energies. We argue that there are no periodic wave functions in the RDM but close to the critical energies there exist periodic envelopes. These envelopes are given by the nondisordered properties of the system.
The effect of short recovery period investment on least-cost generation system expansion
International Nuclear Information System (INIS)
The effect of the short recovery period of private investment on least-cost generation system expansion is analysed, and a trade-off method for generation system expansion, which gives consideration to both the least-cost strategy and the short recovery period of private investment, is presented. First, the optimal mix of generation units under a standard recovery period for all units is established, and then the surcharge, due to the difference between the short recovery period and the standard recovery period, is calculated and shared between all units. The former is an optimization to make best use of natural resources, and the latter is a trade-off method to spread the surcharge throughout the system. (Author)
Dynamic behaviors of the periodic Lotka-Volterra competing system with impulsive perturbations
International Nuclear Information System (INIS)
In this paper, we investigate a classical periodic Lotka-Volterra competing system with impulsive perturbations. The conditions for the linear stability of trivial periodic solution and semi-trivial periodic solutions are given by applying Floquet theory of linear periodic impulsive equation, and we also give the conditions for the global stability of these solutions as a consequence of some abstract monotone iterative schemes introduced in this paper, which will be also used to get some sufficient conditions for persistence. By using the method of coincidence degree, the conditions for the existence of at least one strictly positive (componentwise) periodic solution are derived. The theoretical results are confirmed by a specific example and numerical simulations. It shows that the dynamic behaviors of the system we consider are quite different from the corresponding system without pulses
Self-similarities of periodic structures for a discrete model of a two-gene system
Energy Technology Data Exchange (ETDEWEB)
Souza, S.L.T. de, E-mail: thomaz@ufsj.edu.br [Departamento de Física e Matemática, Universidade Federal de São João del-Rei, Ouro Branco, MG (Brazil); Lima, A.A. [Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, MG (Brazil); Caldas, I.L. [Instituto de Física, Universidade de São Paulo, São Paulo, SP (Brazil); Medrano-T, R.O. [Departamento de Ciências Exatas e da Terra, Universidade Federal de São Paulo, Diadema, SP (Brazil); Guimarães-Filho, Z.O. [Aix-Marseille Univ., CNRS PIIM UMR6633, International Institute for Fusion Science, Marseille (France)
2012-03-12
We report self-similar properties of periodic structures remarkably organized in the two-parameter space for a two-gene system, described by two-dimensional symmetric map. The map consists of difference equations derived from the chemical reactions for gene expression and regulation. We characterize the system by using Lyapunov exponents and isoperiodic diagrams identifying periodic windows, denominated Arnold tongues and shrimp-shaped structures. Period-adding sequences are observed for both periodic windows. We also identify Fibonacci-type series and Golden ratio for Arnold tongues, and period multiple-of-three windows for shrimps. -- Highlights: ? The existence of noticeable periodic windows has been reported recently for several nonlinear systems. ? The periodic window distributions appear highly organized in two-parameter space. ? We characterize self-similar properties of Arnold tongues and shrimps for a two-gene model. ? We determine the period of the Arnold tongues recognizing a Fibonacci-type sequence. ? We explore self-similar features of the shrimps identifying multiple period-three structures.
Periodic orbits in magnetic fields and Ricci curvature of Lagrangian systems
Bahri, A.; Taimanov, I. A.
1995-01-01
We consider a periodic problem for the motion of a charged particle in a magnetic field. Introducing a notion of Ricci curvature for such Lagrangian systems and using the methods of the calculus of variations in the large, we prove the existence of periodic motions for such particles under a condition of positivity of the Ricci curvature.
On the genericity of nonvanishing instability intervals in periodic Dirac systems
Energy Technology Data Exchange (ETDEWEB)
Schmidt, K.M. (Muenchen Univ. (Germany). Mathematisches Inst.)
1993-09-01
Using Floquet-Lyapunov theory, it is shown that for Baire-almost every periodic potential the Dirac system has all its instability intervals open. Consequently, one-dimensional Dirac operators with periodic potentials generically posses infinitely many spectral gaps. These results also hold true if only even potentials are admitted. (orig.).
Scattering problem for quantum system with time-dependent periodic Hamiltonian
International Nuclear Information System (INIS)
Scattering theory for quantum systems located in time-dependent periodic strong field is considered. Scattering matrix is constructed in the quasi-energy states basis. Transition operators are introduced, perturbation series is constructed, interstates transition rate is calculated. Optical theorem is generalized in case of periodic field. (author). 7 refs
International Nuclear Information System (INIS)
Periodic waves for a system of coupled, higher order nonlinear Schroedinger equations with third order dispersion are established. These periodic waves can be expressed as a single or a product of theta functions. This choice of theta functions as a basis also leads to new solutions of the more familiar coupled nonlinear Schroedinger equations, or the Manakov model
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.
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
Periodic orbits and non-integrability of Henon-Heiles systems
International Nuclear Information System (INIS)
We apply the averaging theory of second order to study the periodic orbits for a generalized Henon-Heiles system with two parameters, which contains the classical Henon-Heiles system. Two main results are shown. The first result provides sufficient conditions on the two parameters of these generalized systems, which guarantee that at any positive energy level, the Hamiltonian system has periodic orbits. These periodic orbits form in the whole phase space a continuous family of periodic orbits parameterized by the energy. The second result shows that for the non-integrable Henon-Heiles systems in the sense of Liouville-Arnol'd, which have the periodic orbits analytically found with averaging theory, cannot exist any second first integral of class C1. In particular, for any second first integral of class C1, we prove that the classical Henon-Heiles system and many generalizations of it are not integrable in the sense of Liouville-Arnol'd. Moreover, the tools we use for studying the periodic orbits and the non-Liouville-Arnol'd integrability can be applied to Hamiltonian systems with an arbitrary number of degrees of freedom.
Periodic orbits in non-integrable hamiltoniam systems with two degrees of freedom
International Nuclear Information System (INIS)
We present extensive numerical data concerning the periodics orbits of a non integrable two degrees of freedom hamiltoniam system. These periodics orbits form a one-parameter family and the data are displayed in a plot of energy x period. These orbits exhibit several kinds of bifurcations not predicted in the generic study by K.R. Meyer (Trans. Am. Math. Soc., 1970) due to the existence of symmetries in the hamiltonian. Using a perturbative treatment in the neighbourhood of the periodic trajectories, we analytically compute the effect of these symmetries in the bifurcations. These results are in perfect agreement with those obtained numerically. (author)
Zhigang Liu; Anping Chen; Jinde Cao; Fengde Chen
2004-01-01
By using the continuation theorem of Mawhin's coincidence degree theory, some sufficient conditions are obtained ensuring the existence of multiple positive periodic solutions of a discrete time predator-prey systems with type IV functional responses.
Study and discussion on periodic test system and procedure management in nuclear power plant
International Nuclear Information System (INIS)
The author discussed and studied the document system, concerned with references, test contents and classifications, of periodic test in nuclear power plant and presented the research results as well as the point of view of author's in these respects
Energy Technology Data Exchange (ETDEWEB)
Mirus, K.A.
1998-06-01
In this thesis, the possibility of controlling low- and high-dimensional chaotic systems by periodically driving an accessible system parameter is examined. This method has been carried out on several numerical systems and the MST Reversed Field Pinch. The numerical systems investigated include the logistic equation, the Lorenz equations, the Roessler equations, a coupled lattice of logistic equations, a coupled lattice of Lorenz equations, the Yoshida equations, which model tearing mode fluctuations in a plasma, and a neural net model for magnetic fluctuations on MST. This method was tested on the MST by sinusoidally driving a magnetic flux through the toroidal gap of the device. Numerically, periodic drives were found to be most effective at producing limit cycle behavior or significantly reducing the dimension of the system when the perturbation frequency was near natural frequencies of unstable periodic orbits embedded in the attractor of the unperturbed system. Several different unstable periodic orbits have been stabilized in this way for the low-dimensional numerical systems, sometimes with perturbation amplitudes that were less than 5% of the nominal value of the parameter being perturbed. In high-dimensional systems, limit cycle behavior and significant decreases in the system dimension were also achieved using perturbations with frequencies near the natural unstable periodic orbit frequencies. Results for the MST were not this encouraging, most likely because of an insufficient drive amplitude, the extremely high dimension of the plasma behavior, large amounts of noise, and a lack of stationarity in the transient plasma pulses.
International Nuclear Information System (INIS)
In this thesis, the possibility of controlling low- and high-dimensional chaotic systems by periodically driving an accessible system parameter is examined. This method has been carried out on several numerical systems and the MST Reversed Field Pinch. The numerical systems investigated include the logistic equation, the Lorenz equations, the Roessler equations, a coupled lattice of logistic equations, a coupled lattice of Lorenz equations, the Yoshida equations, which model tearing mode fluctuations in a plasma, and a neural net model for magnetic fluctuations on MST. This method was tested on the MST by sinusoidally driving a magnetic flux through the toroidal gap of the device. Numerically, periodic drives were found to be most effective at producing limit cycle behavior or significantly reducing the dimension of the system when the perturbation frequency was near natural frequencies of unstable periodic orbits embedded in the attractor of the unperturbed system. Several different unstable periodic orbits have been stabilized in this way for the low-dimensional numerical systems, sometimes with perturbation amplitudes that were less than 5% of the nominal value of the parameter being perturbed. In high-dimensional systems, limit cycle behavior and significant decreases in the system dimension were also achieved using perturbations with frequencies near the natural unstable periodic orbit frequencies. Results for the MST were not this encouraging, most likely because of an insufficient drive amplitude, the extremely high dimension of the plasma behavior, large amounts of noise, and a lack of stationarity in the transient plasma pulses
Saiki, Y
2007-01-01
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.
On the ionization of a Keplerian binary system by periodic gravitational radiation
Chicone, C; Retzloff, D G; Chicone, Carmen; Mashhoon, Bahram; Retzloff, David
1996-01-01
The gravitational ionization of a Keplerian binary system via normally incident periodic gravitational radiation of definite helicity is discussed. The periodic orbits of the planar tidal equation are investigated on the basis of degenerate continuation theory. The relevance of the Kolmogorov-Arnold-Moser theory to the question of gravitational ionization is elucidated, and it is conjectured that the process of ionization is closely related to the Arnold diffusion of the perturbed system.
Research on anti-disturbance property of HFETRC period monitoring system
International Nuclear Information System (INIS)
The anti-disturbance problem of the period monitoring system for test reactor critical assembly is mainly discussed and how to judge and search for the interference source using spotting experimental methods starting from the practical engineering without special equipment is introduced. So the electro-magnetic interference is removed. After finding out the reason, four measures are adopted to build up the anti-disturbance ability of the period monitoring system. (authors)
A general approach to the localization of unstable periodic orbits in chaotic dynamical systems
Schmelcher, P; Diakonos, F. K.
1997-01-01
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 ...
International Nuclear Information System (INIS)
Bifurcation characteristics of the Langford system in a general form are systematically analysed, and nonlinear controls of periodic solutions changing into invariant tori in this system are achieved. Analytical relationship between control gain and bifurcation parameter is obtained. Bifurcation diagrams are drawn, showing the results of control for secondary Hopf bifurcation and sequences of bifurcations route to chaos. Numerical simulations of quasi-periodic tori validate analytic predictions
The Period-Ratio and Mass-Ratio Correlation in Extra-Solar Multiple Planetary Systems
Jiang, Ing-Guey; Hung, Wen-Liang
2015-01-01
Employing the data from orbital periods and masses of extra-solar planets in 166 multiple planetary systems, the period-ratio and mass-ratio of adjacent planet pairs are studied. The correlation between the period-ratio and mass-ratio is confirmed and found to have a correlation coefficient of 0.5303 with a 99% confidence interval (0.3807, 0.6528). A comparison with the distribution of synthetic samples from a Monte Carlo simulation reveals the imprint of planet-planet interactions on the formation of adjacent planet pairs in multiple planetary systems.
The period-ratio and mass-ratio correlation in extra-solar multiple planetary systems
Jiang, Ing-Guey; Yeh, Li-Chin; Hung, Wen-Liang
2015-04-01
Employing the data from orbital periods and masses of extra-solar planets in 166 multiple planetary systems, the period ratio and mass ratio of adjacent planet pairs are studied. The correlation between the period ratio and mass ratio is confirmed, with a correlation coefficient of 0.5303 with a 99 per cent 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.
Localization of periodic orbits of the Roessler system under variation of its parameters
Energy Technology Data Exchange (ETDEWEB)
Starkov, Konstantin E. [CITEDI-IPN, Av. del Parque 1310, Mesa de Otay, Tijuana, BC (Mexico)]. E-mail: konst@citedi.mx; Starkov, Konstantin K. [UABC - Campus Tijuana, Facultad de Ciencias Quimicas e Ingenieria, Calzada Tecnologico, Mesa de Otay, Tijuana, BC (Mexico)
2007-08-15
The localization problem of compact invariant sets of the Roessler system is considered in this paper. The main interest is attracted to a localization of periodic orbits. We establish a number of algebraic conditions imposed on parameters under which the Roessler system has no compact invariant sets contained in half-spaces z > 0; z < 0 and in some others. We prove that if parameters (a, b, c) of the Roessler system are such that this system has no equilibrium points then it has no periodic orbits as well. In addition, we give localization conditions of compact invariant sets by using linear functions and one quadratic function.
Directory of Open Access Journals (Sweden)
N. Raos
2015-03-01
Full Text Available The teaching of the periodic system in the historical context has an advantage because students in this way comprehend more easily the basic chemical concepts, such as relative atomic mass, proton number, chemical element, elementary substance, equivalent and molar mass. The story of the periodic system also shows the following: (1 Before a key scientific discovery there is a long period of data collection and systematization, (2 Theories in chemistry must be based on experimental results and methods, (3 The advancement of science is also determined by the development of concepts, and (4 Scientific theories usually do not contradict but support each other. Therefore, the historical periodic system (based on relative atomic mass is not obsolete, but complementary to the modern.
Periodic orbits and their stability in the Rössler prototype-4 system
International Nuclear Information System (INIS)
For the Rössler prototype-4 system x.=?y?z, y.=x, z.=?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.
Stable 1 2 Resonant Periodic Orbits in Elliptic Three-Body Systems
Haghighipour, N; Varadi, F; Moore, W B; Haghighipour, Nader; Couetdic, Jocelyn; Varadi, Ferenc; Moore, William B.
2003-01-01
The results of an extensive numerical study of the periodic orbits of planar, elliptic restricted three-body planetary systems consisting of a star, an inner massive planet and an outer mass-less body in the external 1:2 mean-motion resonance are presented. Using the method of differential continuation, the locations of the resonant periodic orbits of such systems are identified and through an extensive study of their phase-parameter space, it is found that the majority of the resonant periodic orbits are unstable. For certain values of the mass and the orbital eccentricity of the inner planet, however, stable periodic orbits can be found. The applicability of such studies to the 1:2 resonance of the extrasolar planetary system GJ876 is also discussed.
International Nuclear Information System (INIS)
A procedure to obtain a near equilibrium phase space distribution function has been derived for beams with space charge effects in a generalized periodic focusing transport channel. The method utilizes the Lie transform perturbation theory to canonically transform to slowly oscillating phase space coordinates. The procedure results in transforming the periodic focusing system to a constant focusing one, where equilibrium distributions can be found. Transforming back to the original phase space coordinates yields an equilibrium distribution function corresponding to a constant focusing system along with perturbations resulting from the periodicity in the focusing. Examples used here include linear and nonlinear alternating gradient focusing systems. It is shown that the nonlinear focusing components can be chosen such that the system is close to integrability. The equilibrium distribution functions are numerically calculated, and their properties associated with the corresponding focusing system are discussed
Cyclical period changes in HT Cas: a clear difference between systems above and below the period gap
Borges, B W; Papadimitriou, C; Giannakis, O
2007-01-01
We report the identification of cyclical changes in the orbital period of the eclipsing cataclysmic variable HT Cas. We measured new white dwarf mid-eclipse timings and combined with published measurements to construct an observed-minus-calculated diagram covering 29 years of observations. The data present cyclical variations that can be fitted by a linear plus sinusoidal function with period 36 yr and semi-amplitude ~ 40 s. The statistical significance of this period by an F-test is larger than 99.9 per cent. We combine our results with those in the literature to revisit the issue of cyclical period changes in cataclysmic variables and their interpretation in terms of a solar-type magnetic activity cycle in the secondary star. A diagram of fractional period change (Delta P/P) versus the angular velocity of the active star (Omega) for cataclysmic variables, RS CVn, W UMa and Algols reveal that close binaries with periods above the gap (secondaries with convective envelopes) satisfy a relationship Delta P/P \\p...
DEFF Research Database (Denmark)
Rudner, Mark Spencer; Lindner, Netanel; Berg, Erez; Levin, Michael
2013-01-01
Recently, several authors have investigated topological phenomena in periodically driven systems of noninteracting particles. These phenomena are identified through analogies between the Floquet spectra of driven systems and the band structures of static Hamiltonians. Intriguingly, these works 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 s...
H2 OPTIMAL CONTROLLERS FOR A LARGE CLASS OF LINEAR STOCHASTIC SYSTEMS WITH PERIODIC COEFFICIENTS
Directory of Open Access Journals (Sweden)
Adrian-Mihail Stoica
2011-07-01
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.
Permanence and Positive Periodic Solutions of a Discrete Delay Competitive System
Directory of Open Access Journals (Sweden)
Zhijun Liu
2010-01-01
Full Text Available A discrete time non-autonomous two-species competitive system with delays is proposed, which involves the influence of many generations on the density of species population. Sufficient conditions for permanence of the system are given. When the system is periodic, by using the continuous theorem of coincidence degree theory and constructing a suitable Lyapunov discrete function, sufficient conditions which guarantee the existence and global attractivity of positive periodic solutions are obtained. As an application, examples and their numerical simulations are presented to illustrate the feasibility of our main results.
Different types of nonlinear localized and periodic waves in an erbium-doped fiber system
Ren, Yang; Yang, Zhan-Ying; Liu, Chong; Yang, Wen-Li
2015-12-01
We study nonlinear waves on a plane-wave background in an erbium-doped fiber system, which is governed by the coupled nonlinear Schrödinger and the Maxwell-Bloch equations. We find that prolific different types of nonlinear localized and periodic waves do exist in the system, including multi-peak soliton, periodic wave, antidark soliton, and W-shaped soliton (as well as the known bright soliton, breather, and rogue wave). In particular, the dynamics of these waves can be extracted from a unified exact solution, and the corresponding existence conditions are presented explicitly. Our results demonstrate the structural diversity of the nonlinear waves in this system.
Local electric dipole moments for periodic systems via density functional theory embedding
International Nuclear Information System (INIS)
We describe a novel approach for the calculation of local electric dipole moments for periodic systems. Since the position operator is ill-defined in periodic systems, maximally localized Wannier functions based on the Berry-phase approach are usually employed for the evaluation of local contributions to the total electric dipole moment of the system. We propose an alternative approach: within a subsystem-density functional theory based embedding scheme, subset electric dipole moments are derived without any additional localization procedure, both for hybrid and non-hybrid exchange–correlation functionals. This opens the way to a computationally efficient evaluation of local electric dipole moments in (molecular) periodic systems as well as their rigorous splitting into atomic electric dipole moments. As examples, Infrared spectra of liquid ethylene carbonate and dimethyl carbonate are presented, which are commonly employed as solvents in Lithium ion batteries
Local electric dipole moments for periodic systems via density functional theory embedding
Energy Technology Data Exchange (ETDEWEB)
Luber, Sandra, E-mail: sandra.luber@chem.uzh.ch [Institut für Chemie, Universität Zürich, Winterthurerstrasse 190, 8057 Zürich (Switzerland)
2014-12-21
We describe a novel approach for the calculation of local electric dipole moments for periodic systems. Since the position operator is ill-defined in periodic systems, maximally localized Wannier functions based on the Berry-phase approach are usually employed for the evaluation of local contributions to the total electric dipole moment of the system. We propose an alternative approach: within a subsystem-density functional theory based embedding scheme, subset electric dipole moments are derived without any additional localization procedure, both for hybrid and non-hybrid exchange–correlation functionals. This opens the way to a computationally efficient evaluation of local electric dipole moments in (molecular) periodic systems as well as their rigorous splitting into atomic electric dipole moments. As examples, Infrared spectra of liquid ethylene carbonate and dimethyl carbonate are presented, which are commonly employed as solvents in Lithium ion batteries.
Directory of Open Access Journals (Sweden)
Xuan Li
2009-01-01
Full Text Available This study investigates the problem of integrity against actuator failures for networked control systems under variable-period sampling. Assuming that the distance between any two consecutive sampling instants is less than a given bound, by using the input delay approach, the networked control systems under variable-period sampling are transformed into the continuous-time networked control systems under time-varying delays. Then the existence conditions of guaranteed cost fault-tolerant control law is testified in terms of the Lyapunov stability theory combined with Linear Matrix Inequalities (LMIs. Furthermore, the guaranteed cost fault-tolerant controller gain and the minimization guaranteed cost can be obtained by solving a minimization problem. A numerical simulation example demonstrates the conclusions are feasible and effective. The proposed control method resolves the problems of variable-period sampling and actuator failures, which meets the requirements in industrial networked control systems.
Existence of positive periodic solution of mutualism system with several delays
Energy Technology Data Exchange (ETDEWEB)
Wu Haihui [College of Mathematics and Computer Science, Fuzhou University, Fuzhou 350002 (China); Department of Computer Science and Technology, Sunshine College, Fuzhou University, Fuzhou 350002 (China); Xia Yonghui [College of Mathematics and Computer Science, Fuzhou University, Fuzhou 350002 (China)], E-mail: yhxia@fzu.edu.cn; Lin Muren [College of Mathematics and Computer Science, Fuzhou University, Fuzhou 350002 (China)
2008-04-15
In this paper, by using Mawhin coincidence degree, some sufficient conditions are obtained for the global existence of positive periodic solutions of a mutualism systems with bounded and unbounded delays. Our results generalize significantly improve those of Gopalsamy and He [Gopalsamy K, He XZ. Persistence, attractivity, and delay in facultative mutualism. J Math Anal Appl 1997;215:154-73], Yang et al. [Yang F, Jiang D, Ying A. Existence of positive solution of multidelays facultative mutualism system. J Eng Math 2002;3:64-8], Chen et al. [Chen FD, Shi JL, Chen XX. Periodicity in Lotka-Volterra facultative mutualism system with several delays. J Eng Math 2004;21(3)] and Xia and Lin [Xia YH, Lin M, Existence of positive periodic solution of mutualism system with infinite delays. Ann Diff Eqs 2005;21(3):448-53].
Local electric dipole moments for periodic systems via density functional theory embedding
Luber, Sandra
2014-12-01
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.
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
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
Periodic solutions of certain third order nonlinear differential systems with delay
International Nuclear Information System (INIS)
This paper investigates the existence of 2?-periodic solutions of systems of third-order nonlinear differential equations, with delay, under varied assumptions. The results obtained extend earlier works of Tejumola and generalize to third order systems those of Conti, Iannacci and Nkashama as well as DePascale and Iannacci and Iannacci and Nkashama. 16 refs
18 CFR 301.4 - Exchange Period Average System Cost determination.
2010-04-01
... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Exchange Period Average System Cost determination. 301.4 Section 301.4 Conservation of Power and Water Resources FEDERAL ENERGY... Dialogue CHWM contracts, Bonneville will use the following approach: (1) Use the RHWM System Resources...
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.
Optical Monitoring and Period Analysis of High Mass X-Ray Binary System BD+53 2262
Zurita, Nathaly; Hintz, E. G.
2012-05-01
High mass X-ray binary systems (HMXB) are usually composed of a B spectral type star and a neutron star. These systems have been primarily observed in the X-ray regime and as such their optical properties have not been thoroughly studied. We hypothesize that variability/periodicity in the optical brightness should be present and correlate with variability at other wavelengths. For the last five summers, optical observations of HMXB system BD+53 2262 have been gathered on the David Derrick 16’’ telescope located at Brigham Young University. To probe for long-term and short term variability, observations were taken in quick succession in one filter over the course of a night and also shorter observations through multiple filters spaced over many nights. The observations are primarily in the Johnson V filter, with B and I added in 2010, and R in 2011. We present optical light curves for five years of observations of the system BD+53 2262. There is a definite decrease in magnitude in the past five years and small monthly variations in three of the four years. These indicate a long term periodicity on the range of years and some shorter term periodicity in the range of months, consistent with what was expected. Period analysis has been done on the data and preliminary results will be presented. We will keep observing this system to see if there is further evidence of long term periodicity and to see if the monthly variations continue.
Existence and global stability of positive periodic solutions of a discrete delay competition system
Wan-Tong Li; Hai-Feng Huo
2003-01-01
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.
Jung, Soyeun
2012-01-01
In the previous paper \\cite{J1}, we established pointwise bounds for the Green function of the linearized equation associated with spatially periodic traveling waves $\\bar u$ of a system of reaction diffusion equations, and also obtained pointwise nonlinear stability and behavior of $\\bar u$ under small perturbations. In this paper, using periodic resolvent kernels and the Bloch-decomposition, we establish pointwise bounds for the Green function of the linearized equation as...
DMFT study of the local correlation effects in quasi-periodic system
Takemori, Nayuta; Koga, Akihisa
2015-03-01
We study a two-dimensional Hubbard model on a Penrose lattice by means of the real-space dynamical mean-field theory. Calculating the renormalization factor and density of states at each site, we discuss local electron correlations on the quasi-periodic structure. It is found that the renormalized metallic state appears near the Mott transition in the Penrose lattice system. We also address a spatially-dependent renormalization characteristic of the quasi-periodic lattice.
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
The Period-Ratio and Mass-Ratio Correlation in Extra-Solar Multiple Planetary Systems
Jiang, Ing-Guey; Yeh, Li-Chin; Hung, Wen-Liang
2015-01-01
Employing the data from orbital periods and masses of extra-solar planets in 166 multiple planetary systems, the period-ratio and mass-ratio of adjacent planet pairs are studied. The correlation between the period-ratio and mass-ratio is confirmed and found to have a correlation coefficient of 0.5303 with a 99% confidence interval (0.3807, 0.6528). A comparison with the distribution of synthetic samples from a Monte Carlo simulation reveals the imprint of planet-planet interactions on the for...
Kunder, Andrea; Stetson, Peter B; Bono, Giuseppe; Nemec, James M; de Propris, Roberto; Monelli, Matteo; Cassisi, Santi; Andreuzzi, Gloria; Dall'Ora, Massimo; Di Cecco, Alessandra; Zoccali, Manuela
2010-01-01
We present period change rates (dP/dt) for 42 RR Lyrae variables in the globular cluster IC$\\,$4499. Despite clear evidence of these period increases or decreases, the observed period change rates are an order of magnitude larger than predicted from theoretical models of this cluster. We find there is a preference for increasing periods, a phenomenon observed in most RR Lyrae stars in Milky Way globular clusters. The period-change rates as a function of position in the period-amplitude plane are used to examine possible evolutionary effects in OoI clusters, OoII clusters, field RR Lyrae stars and the mixed-population cluster $\\omega$~ Centauri. It is found that there is no correlation between the period change rate and the typical definition of Oosterhoff groups. If the RR Lyrae period changes correspond with evolutionary effects, this would be in contrast to the hypothesis that RR Lyrae variables in OoII systems are evolved HB stars that spent their ZAHB phase on the blue side of the instability strip. This ...
Kunder, Andrea; Walker, Alistair; 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
2011-01-01
We present period change rates (dP/dt) for 42 RR Lyrae variables in the globular cluster IC 4499. Despite clear evidence of these period increases or decreases, the observed period change rates are an order of magnitude larger than predicted from theoretical models of this cluster. We find that 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 ? 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 horizontal-branch stars that spent their zero-age horizontal-branch phase on the blue side of the instability strip. This may suggest that age may not be the primary explanation for the Oosterhoff types. Based in part on observations made with the European Southern Observatory telescopes obtained from the ESO/ST-ECF Science Archive Facility.
International Nuclear Information System (INIS)
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 that 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 ? 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 horizontal-branch stars that spent their zero-age horizontal-branch phase on the blue side of the instability strip. This may suggest that age may not be the primary explanation for the Oosterhoff types.
The effect of volatile bubble growth rate on the periodic dynamics of shallow volcanic systems
Directory of Open Access Journals (Sweden)
I. L'Heureux
2010-04-01
Full Text Available Many volcanic eruptions exhibit periodic behavior. For instance, periodic ground inflations and deflations in proximity to a volcano are the consequences of periodic overpressure variations in the magma conduit and periodic magma flow rate. The period varies from a few hours to many years, depending on the volcano parameters. On the other hand, volatile components exsolve from an ascending magma by forming bubbles. The strong dependence of the melt viscosity with the volatile concentration generates a positive feedback on the magma flow. We consider here the effect of the growth of volatile bubbles on the dynamics of a magmatic flow in a shallow volcanic system. Various expressions for the bubble growth rate are treated, thus generalizing previous work. In particular, a growth rate law derived from a recent many-bubble theory is considered. It is seen that, for a range of flow rate values at the base of the magma conduit, the system undergoes a Hopf bifurcation. Periodic solutions compatible with the observations are generated. This work shows that measurements of volcanic activity have the potential to test various bubble growth models in magmatic systems.
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)
Classical and Quantum Transport in One-Dimensional Periodically Kicked Systems
Dana, Itzhack
2013-01-01
This paper is a brief review of classical and quantum transport phenomena, as well as related spectral properties, exhibited by one-dimensional periodically kicked systems. Two representative and fundamentally different classes of systems will be considered, those satisfying the classical Kolmogorov-Arnol'd-Moser scenario and those which not. The experimental realization of some of these systems using atom-optics methods will be mentioned.
Directory of Open Access Journals (Sweden)
Y. Saiki
2007-09-01
Full Text Available An infinite number of unstable periodic orbits (UPOs are embedded in a chaotic system which models some complex phenomenon. Several algorithms which extract UPOs numerically from continuous-time chaotic systems have been proposed. In this article the damped Newton-Raphson-Mees algorithm is reviewed, and some important techniques and remarks concerning the practical numerical computations are exemplified by employing the Lorenz system.
Onset of Secular Chaos in Planetary Systems: Period Doubling & Strange Attractors
Batygin, Konstantin; Morbidelli, Alessandro
2011-01-01
As a result of resonance overlap, planetary systems can exhibit chaotic motion. Planetary chaos has been studied extensively in the Hamiltonian framework, however, the presence of chaotic motion in systems where dissipative effects are important, has not been thoroughly investigated. Here, we study the onset of stochastic motion in presence of dissipation, in the context of classical perturbation theory, and show that planetary systems approach chaos via a period-doubling ro...
Periodic solutions for small and large delays in a tumor-immune system model
Directory of Open Access Journals (Sweden)
Radouane Yafia
2006-09-01
Full Text Available In this paper we study the Hopf bifurcation for the tumor-immune system model with one delay. This model is governed by a system of two differential equations with one delay. We show that the system may have periodic solutions for small and large delays for some critical value of the delay parameter via Hopf bifurcation theorem bifurcating from the non trivial steady state.
Periodic response of nonlinear dynamical system with large number of degrees of freedom
Indian Academy of Sciences (India)
B P Patel; S M Ibrahim; Y Nath
2009-12-01
In this paper, a methodology based on shooting technique and Newmark's time integration scheme is proposed for predicting the periodic responses of nonlinear systems directly from solution of second order equations of motion without transforming to double ï¬rst order equations. The proposed methodology is quite suitable for systems with large number of degrees of freedom such as the banded system of equations from ï¬nite element discretization.
Modal Vibration Control in Periodic Time-Varying Structures with Focus on Rotor-Blade Systems
DEFF Research Database (Denmark)
Christensen, Rene Hardam; Santos, Ilmar
2003-01-01
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......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...... 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...
Modal Vibration Control in Periodic Time-Varying Structures with Focus on Rotor Blade Systems
DEFF Research Database (Denmark)
Christensen, Rene Hardam; Santos, Ilmar
2004-01-01
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......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...... 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...
Water Recovery System Design to Accommodate Dormant Periods for Manned Missions
Tabb, David; Carter, Layne
2015-01-01
Future manned missions beyond lower Earth orbit may include intermittent periods of extended dormancy. Under the NASA Advanced Exploration System (AES) project, NASA personnel evaluated the viability of the ISS Water Recovery System (WRS) to support such a mission. The mission requirement includes the capability for life support systems to support crew activity, followed by a dormant period of up to one year, and subsequently for the life support systems to come back online for additional crewed missions. Dormancy could be a critical issue due to concerns with microbial growth or chemical degradation that might prevent water systems from operating properly when the crewed mission began. As such, it is critical that the water systems be designed to accommodate this dormant period. This paper details the results of this evaluation, which include identification of dormancy issues, results of testing performed to assess microbial stability of pretreated urine during dormancy periods, and concepts for updating to the WRS architecture and operational concepts that will enable the ISS WRS to support the dormancy requirement.
Directory of Open Access Journals (Sweden)
J. Rodrigues Dias
2006-11-01
Full Text Available Systems with different lifetime distributions, associated with increasing, decreasing, constant, and bathtub-shaped hazard rates, are examined in this paper. It is assumed that a failure is only detected if systems are inspected. New approximate solutions for the inspection period and for the expected duration of hidden faults are presented, on the basis of the assumption that only periodic and perfect inspections are carried out. By minimizing total expected cost per unit of time, on the basis of numerical results and a range of comparisons, the conclusion is drawn that these new approximate solutions are extremely useful and simple to put into practice.
Hwang, Sunghwan
1997-08-01
One of the most prominent features of helicopter rotor dynamics in forward flight is the periodic coefficients in the equations of motion introduced by the rotor rotation. The frequency response characteristics of such a linear time periodic system exhibits sideband behavior, which is not the case for linear time invariant systems. Therefore, a frequency domain identification methodology for linear systems with time periodic coefficients was developed, because the linear time invariant theory cannot account for sideband behavior. The modulated complex Fourier series was introduced to eliminate the smearing effect of Fourier series expansions of exponentially modulated periodic signals. A system identification theory was then developed using modulated complex Fourier series expansion. Correlation and spectral density functions were derived using the modulated complex Fourier series expansion for linear time periodic systems. Expressions of the identified harmonic transfer function were then formulated using the spectral density functions both with and without additive noise processes at input and/or output. A procedure was developed to identify parameters of a model to match the frequency response characteristics between measured and estimated harmonic transfer functions by minimizing an objective function defined in terms of the trace of the squared frequency response error matrix. Feasibility was demonstrated by the identification of the harmonic transfer function and parameters for helicopter rigid blade flapping dynamics in forward flight. This technique is envisioned to satisfy the needs of system identification in the rotating frame, especially in the context of individual blade control. The technique was applied to the coupled flap-lag-inflow dynamics of a rigid blade excited by an active pitch link. The linear time periodic technique results were compared with the linear time invariant technique results. Also, the effect of noise processes and initial parameter guess on the identification procedure were investigated. To study the effect of elastic modes, a rigid blade with a trailing edge flap excited by a smart actuator was selected and system parameters were successfully identified, but with some expense of computational storage and time. Conclusively, the linear time periodic technique substantially improved the identified parameter accuracy compared to the linear time invariant technique. Also, the linear time periodic technique was robust to noises and initial guess of parameters. However, an elastic mode of higher frequency relative to the system pumping frequency tends to increase the computer storage requirement and computing time.
Pseudo-parity–time symmetry in periodically high-frequency driven systems: perturbative analysis
International Nuclear Information System (INIS)
We investigate the periodically modulated two-level systems with balanced gain and loss by means of a multiple-scale asymptotic analysis. The pseudo-parity–time symmetry (2013 Phys. Rev. Lett. 110 243902), which is often neglected in exact numerical simulations and totally lost in the commonly used high-frequency averaging approximation, has been fully understood in the framework of the second-order perturbative theory. Our work indicates that the multiple-scale asymptotic expansion method can be used to predict precisely some subtle and important dynamical behaviors in periodically driven systems. (paper)
Periodic orbit theory for the continuum of general mixed-dynamical systems
Kaidel, J; Brack, M
2003-01-01
We present a semiclassical method to determine the spectral density in the continuum region of general mixed-dynamical systems without restriction to asymptotically vanishing potentials. The spectral density is written in terms of the complex eigenvalues corresponding to the resonances and approximated semiclassically by a trace formula in terms of classical periodic orbits. Applying our method to the well-known two-dimensional H\\'enon-Heiles system, we find that the inclusion of unstable as well as stable, but {\\it real} periodic orbits is sufficient to reproduce the coarse-grained quantum-mechanical results with high accuracy.
Energy Technology Data Exchange (ETDEWEB)
McWilliams, T.P.; Martz, H.F.
1981-01-01
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.
Onset of Secular Chaos in Planetary Systems: Period Doubling & Strange Attractors
Batygin, Konstantin
2011-01-01
As a result of resonance overlap, planetary systems can exhibit chaotic motion. Planetary chaos has been studied extensively in the Hamiltonian framework, however, the presence of chaotic motion in systems where dissipative effects are important, has not been thoroughly investigated. Here, we study the onset of stochastic motion in presence of dissipation, in the context of classical perturbation theory, and show that planetary systems approach chaos via a period-doubling route as dissipation is gradually reduced. Furthermore, we demonstrate that chaotic strange attractors can exist in mildly damped systems. The results presented here are of interest for understanding the early dynamical evolution of chaotic planetary systems, as they may have transitioned to chaos from a quasi-periodic state, dominated by dissipative interactions with the birth nebula.
Periodic orbit analysis of a system with continuous symmetry—A tutorial
Budanur, Nazmi Burak; Borrero-Echeverry, Daniel; Cvitanovi?, Predrag
2015-07-01
Dynamical systems with translational or rotational symmetry arise frequently in studies of spatially extended physical systems, such as Navier-Stokes flows on periodic domains. In these cases, it is natural to express the state of the fluid in terms of a Fourier series truncated to a finite number of modes. Here, we study a 4-dimensional model with chaotic dynamics and SO(2) symmetry similar to those that appear in fluid dynamics problems. A crucial step in the analysis of such a system is symmetry reduction. We use the model to illustrate different symmetry-reduction techniques. The system's relative equilibria are conveniently determined by rewriting the dynamics in terms of a symmetry-invariant polynomial basis. However, for the analysis of its chaotic dynamics, the "method of slices," which is applicable to very high-dimensional problems, is preferable. We show that a Poincaré section taken on the "slice" can be used to further reduce this flow to what is for all practical purposes a unimodal map. This enables us to systematically determine all relative periodic orbits and their symbolic dynamics up to any desired period. We then present cycle averaging formulas adequate for systems with continuous symmetry and use them to compute dynamical averages using relative periodic orbits. The convergence of such computations is discussed.
Periodic orbit analysis of a system with continuous symmetry--A tutorial.
Budanur, Nazmi Burak; Borrero-Echeverry, Daniel; Cvitanovi?, Predrag
2015-07-01
Dynamical systems with translational or rotational symmetry arise frequently in studies of spatially extended physical systems, such as Navier-Stokes flows on periodic domains. In these cases, it is natural to express the state of the fluid in terms of a Fourier series truncated to a finite number of modes. Here, we study a 4-dimensional model with chaotic dynamics and SO(2) symmetry similar to those that appear in fluid dynamics problems. A crucial step in the analysis of such a system is symmetry reduction. We use the model to illustrate different symmetry-reduction techniques. The system's relative equilibria are conveniently determined by rewriting the dynamics in terms of a symmetry-invariant polynomial basis. However, for the analysis of its chaotic dynamics, the "method of slices," which is applicable to very high-dimensional problems, is preferable. We show that a Poincaré section taken on the "slice" can be used to further reduce this flow to what is for all practical purposes a unimodal map. This enables us to systematically determine all relative periodic orbits and their symbolic dynamics up to any desired period. We then present cycle averaging formulas adequate for systems with continuous symmetry and use them to compute dynamical averages using relative periodic orbits. The convergence of such computations is discussed. PMID:26232963
Directory of Open Access Journals (Sweden)
Flashner Henryk
1997-01-01
Full Text Available A point mapping analysis is employed to investigate the stability of periodic systems. The method is applied to simplified rotorcraft models. The proposed approach is based on a procedure to obtain an analytical expression for the period-to-period mapping description of system's dynamics, and its dependence on system's parameters. Analytical stability and bifurcation conditions are then determined and expressed as functional relations between important system parameters. The method is applied to investigate the parametric stability of flapping motion of a rotor and the ground resonance problem encountered in rotorcraft dynamics. It is shown that the proposed approach provides very accurate results when compared with direct numerical results which are assumed to be an “exact solution” for the purpose of this study. It is also demonstrated that the point mapping method yields more accurate results than the widely used classical perturbation analysis. The ability to perform analytical stability studies of systems with multiple degrees-of-freedom is an important feature of the proposed approach since most existing analysis methods are applicable to single degree-of-freedom systems. Stability analysis of higher dimensional systems, such as the ground resonance problems, by perturbation methods is not straightforward, and is usually very cumbersome.
Multi-Period Optimization for Voltage Control System in Transmission Grids
DEFF Research Database (Denmark)
Qin, Nan; Chen, Si
2015-01-01
Automatic Voltage Control (AVC) systems maintain the voltage in an acceptable range and minimize the power loss of the grid by coordinately regulating the controllable components. Switchable shunts and tap-able transformers are expected to be operated as few times as possible. This paper proposes a two-level, multi-period optimal reactive power flow approach. In the upper level, the real-time measurements and short-term forecasts are used as the inputs of the multi-period optimization for one hour with 15 minutes intervals, to minimize the operational cost, subjected to a certain constraints. In the lower level, the optimization is focused on the correction of the voltage violations every single minute based on data from the measurements and state estimation. The presented case study shows that the multi-period optimization in the upper level of AVC system can reduce adjustment times of the discrete components for saving the total operational cost.
Nonlinearity and periodic solution of a standard-beam balance oscillation system
International Nuclear Information System (INIS)
We present the motion equation of the standard-beam balance oscillation system, whose beam and suspensions, compared with the compound pendulum, are connected flexibly and vertically. The nonlinearity and the periodic solution of the equation are discussed by the phase-plane analysis. We find that this kind of oscillation can be equivalent to a standard-beam compound pendulum without suspensions; however, the equivalent mass centre of the standard beam is extended. The derived periodic solution shows that the oscillation period is tightly related to the initial pivot energy and several systemic parameters: beam length, masses of the beam, and suspensions, and the beam mass centre. A numerical example is calculated. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
Can The Periods of Some Extra-Solar Planetary Systems be Quantized?
El Fady Morcos, Abd
A simple formula was derived before by Morcos (2013 ), to relate the quantum numbers of planetary systems and their periods. This formula is applicable perfectly for the solar system planets, and some extra-solar planets , of stars of approximately the same masses like the Sun. This formula has been used to estimate the periods of some extra-solar planet of known quantum numbers. The used quantum numbers were calculated previously by other authors. A comparison between the observed and estimated periods, from the given formula has been done. The differences between the observed and calculated periods for the extra-solar systems have been calculated and tabulated. It is found that there is an error of the range of 10% The same formula has been also used to find the quantum numbers, of some known periods, exo-planet. Keywords: Quantization; Periods; Extra-Planetary; Extra-Solar Planet REFERENCES [1] Agnese, A. G. and Festa, R. “Discretization on the Cosmic Scale Inspirred from the Old Quantum Mechanics,” 1998. http://arxiv.org/abs/astro-ph/9807186 [2] Agnese, A. G. and Festa, R. “Discretizing ups-Andro- medae Planetary System,” 1999. http://arxiv.org/abs/astro-ph/9910534. [3] Barnothy, J. M. “The Stability of the Solar Systemand of Small Stellar Systems,” Proceedings of the IAU Sympo-sium 62, Warsaw, 5-8 September 1973, pp. 23-31. [4] Morcos, A.B. , “Confrontation between Quantized Periods of Some Extra-Solar Planetary Systems and Observations”, International Journal of Astronomy and Astrophysics, 2013, 3, 28-32. [5] Nottale, L. “Fractal Space-Time and Microphysics, To-wards a Theory of Scale Relativity,” World Scientific, London, 1994. [6] Nottale , L., “Scale-Relativity and Quantization of Extra- Solar Planetary Systems,” Astronomy & Astrophysics, Vol. 315, 1996, pp. L9-L12 [7] Nottale, L., Schumacher, G. and Gay, J. “Scale-Relativity and Quantization of the Solar Systems,” Astronomy & Astrophysics letters, Vol. 322, 1997, pp. 1018-10 [8]Nottale, L. “Scale-Relativity and Quantization of Exo- planet Orbital Semi-Major Axes,” Astronomy & Astro- physics, Vol. 361, 2000, pp. 379-387.
International Nuclear Information System (INIS)
In this paper, the Exp-function method is used to obtain generalized solitonary solutions and periodic solutions of the Generalized Zakharov system and (2 + 1)-dimensional Nizhnik-Novikov-Veselov system. It is shown that the Exp-function method, with the help of symbolic computation, provides a powerful mathematical tool for solving nonlinear evolution equations in mathematical physics.
Sturm intersection theory for periodic Jacobi matrices and linear Hamiltonian systems
Schulz-Baldes, Hermann
2011-01-01
Sturm-Liouville oscillation theory for periodic Jacobi operators with matrix entries is discussed and illustrated. The proof simplifies and clarifies the use of intersection theory of Bott, Maslov and Conley-Zehnder. It is shown that the eigenvalue problem for linear Hamiltonian systems can be dealt with by the same approach.
Global Clock, Physical Time Order and Pending Period Analysis in Multiprocessor Systems
Chen, Yunji; Hu, Weiwu
2009-01-01
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...
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
Gravitational Ionization: Periodic Orbits of Binary Systems Perturbed by Gravitational Radiation
Chicone, C.; Mashhoon, B.; Retzloff, D.
1995-01-01
The long term perturbation of a Newtonian binary system by an incident gravitational wave is discussed in connection with the issue of gravitational ionization. The periodic orbits of the planar tidal equation are investigated and the conditions for their existence are presented. The possibility of ionization of a Keplerian orbit via gravitational radiation is discussed.
Gravitational ionization periodic orbits of binary systems perturbed by gravitational radiation
Chicone, C; Retzloff, D G
1995-01-01
The long term perturbation of a Newtonian binary system by an incident gravitational wave is discussed in connection with the issue of gravitational ionization. The periodic orbits of the planar tidal equation are investigated and the conditions for their existence are presented. The possibility of ionization of a Keplerian orbit via gravitational radiation is discussed.
[Periodic and fractal precipitation in ATP-Co(2+)-decoxycholate gel system].
Yin, Wen-Xuan; Liu, Yu-Feng; Zhao, Ying; Bai, Song-Yan; Zhu, Wei-Wei; Weng, Shi-Fu; Gao, Qing-Yu; Wu, Jin-Guang
2009-11-01
In the simulation experiments in vitro of the formation of gallstone, adenosine-triphosphate(ATP)-Co(2+)-deoxycholic acid(DC) gel system was chosen to study the periodic precipitation progress. The effect of ATP on the Co(2+)-DC gel system was also determined, and the structure of the periodic precipitation formed was characterized by FTIR. The results show that the patterns formed in the systems with ATP are different, ATP affected the rate and structure of precipitation through its variable participation in the metal coordination complexes as judged by the phosphate P=O bands and the deoxycholate COO- symmetric and asymmetric vibration bands as measured by FTIR Theses spectroscopic differences were correlated with color and pattern differences in the precipitates. ATP has a more remarkable function than AMP to the modes of patterns, meanwhile the system patterns transform from fractal to periodic precipitation. There is a complex interaction among ATP, sodium deoxycholic and Co2+ with a transparent crystal produced. The crystal is deoxycholic acid and the periodic precipitation is composed of ATP and DC covalent to Co2+. These results indicate that stone formation and remodeling is a dynamic, nonlinear progress. Much of the precipitate, as judged by local differences in composition, is not in equilibrium with the general gel environment. The authors conclude that the formation of gallstone features complex and nonlinear chemical character, in which nucleotides as living material play a very important role. PMID:20101995
A New Method for Studying the Periodic System Based on a Kohonen Neural Network
Chen, David Zhekai
2010-01-01
A new method for studying the periodic system is described based on the combination of a Kohonen neural network and a set of chemical and physical properties. The classification results are directly shown in a two-dimensional map and easy to interpret. This is one of the major advantages of this approach over other methods reported in the…
Directory of Open Access Journals (Sweden)
Xinggui Liu
2011-01-01
Full Text Available In this paper, by using Mawhin's continuation theorem of coincidence degree theory, we establish the existence of at least four positive periodic solutions for a discrete time Lotka-Volterra competitive system with harvesting terms. An example is given to illustrate the effectiveness of our results.
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
The critical period of reservoir systems considering performance indices on Malaysia rivers
Issa Saket Oskoui; Rozi Abdullah; Majid Montaseri
2014-01-01
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...
International Nuclear Information System (INIS)
Especially for nuclear technological plants, periodic inspections of lightning protection systems are of great importance. This article shows the sequence of maintenance programs using the examples of the intermediate storage facilities of the nuclear technological plants Grohnde and Unterweser as well as the central intermediate storage facility in Gorleben and gives a description of the extensive measures of inspecting the external and internal lightning protection and the global earth termination system.
Uniform exponential stability of linear periodic systems in a Banach space
Directory of Open Access Journals (Sweden)
David N. Cheban
2001-01-01
Full Text Available This article is devoted to the study of linear periodic dynamical systems, possessing the property of uniform exponential stability. It is proved that if the Cauchy operator of these systems possesses a certain compactness property, then the asymptotic stability implies the uniform exponential stability. We also show applications to different classes of linear evolution equations, such as ordinary linear differential equations in the space of Banach, retarded and neutral functional differential equations, some classes of evolution partial differential equations.
Orbital periods and Accretion disc structure of four AM CVn systems
Kupfer, T; Levitan, D; Steeghs, D; Marsh, T R; Rutten, R G M; Nelemans, G
2013-01-01
Phase-resolved spectroscopy of four AM CVn systems obtained with the William Herschel Telescope and the Gran Telescopio de Canarias (GTC) is presented. SDSS\\,J120841.96+355025.2 was found to have an orbital period of 52.96$\\pm$0.40\\,min and shows the presence of a second bright spot in the accretion disc. The average spectrum contains strong Mg\\,{\\sc i} and Si\\,{\\sc i/ii} absorption lines most likely originating in the atmosphere of the accreting white dwarf. SDSS\\,J012940.05+384210.4 has an orbital period of 37.555$\\pm$0.003 min. The average spectrum shows the Stark broadened absorption lines of the DB white dwarf accretor. The orbital period is close to the previously reported superhump period of 37.9\\,min. Combined, this results in a period excess $\\epsilon$=0.0092$\\pm$0.0054 and a mass ratio $q=0.031\\pm$0.018. SDSS\\,J164228.06+193410.0 displays an orbital period of 54.20$\\pm$1.60\\,min with an alias at 56.35\\,min. The average spectrum also shows strong Mg\\,{\\sc i} absorption lines, similar to SDSS\\,J120841...
Orbital periods of cataclysmic variables identified by the SDSS. VII. Four new eclipsing systems
Southworth, John; Gansicke, B T; Pyrzas, S
2009-01-01
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...
DEFF Research Database (Denmark)
Rudner, Mark Spencer; Lindner, Netanel
2013-01-01
Recently, several authors have investigated topological phenomena in periodically driven systems of noninteracting particles. These phenomena are identified through analogies between the Floquet spectra of driven systems and the band structures of static Hamiltonians. Intriguingly, these works 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.
International Nuclear Information System (INIS)
In this paper, the continuous time random walk on the circle is studied. We derive the corresponding generalized master equation and discuss the effects of topology, especially important when Levy flights are allowed. Then, we work out the fluid limit equation, formulated in terms of the periodic version of the fractional Riemann-Liouville operators, for which we provide explicit expressions. Finally, we compute the propagator in some simple cases. The analysis presented herein should be relevant when investigating anomalous transport phenomena in systems with periodic dimensions
Time-periodic solutions in an Einstein AdS-massless-scalar-field system.
Maliborski, Maciej; Rostworowski, Andrzej
2013-08-01
We construct time-periodic solutions for a system of a self-gravitating massless scalar field, with a negative cosmological constant, in d+1 spacetime dimensions at spherical symmetry, both perturbatively and numerically. We estimate the convergence radius of the formally obtained perturbative series and argue that it is greater then zero. Moreover, this estimate coincides with the boundary of the convergence domain of our numerical method and the threshold for the black-hole formation. Then we confirm our results with a direct numerical evolution. This also gives strong evidence for the nonlinear stability of the constructed time-periodic solutions. PMID:23952381
International Nuclear Information System (INIS)
The set of the unstable periodic space-time states, characterizing the chaotic space-time dynamics of the electron beam with the supercritical current in the Pierce diode is discussed. The Lyapunov indicators of the revealed instable space-time states of the chaotic dynamics of the distributed self-excited system are calculated. It is shown that change in the set of the unstable periodic states in dependence on the Pierce parameter is determined by change in the various orbits stability, which is demonstrated by the values of senior Lyapunov unstable state index
Directory of Open Access Journals (Sweden)
HirofumiMorishita
2013-11-01
Full Text Available Early temporary windows of heightened brain plasticity called critical periods developmentally sculpt neural circuits and contribute to adult behavior. Regulatory mechanisms of visual cortex development –the preeminent model of experience-dependent critical period plasticity- actively limit adult plasticity and have proved fruitful therapeutic targets to reopen plasticity and rewire faulty visual system connections later in life. Interestingly, these molecular mechanisms have been implicated in the regulation of plasticity in other functions beyond vision. Applying mechanistic understandings of critical period plasticity in the visual cortex to fear circuitry may provide a conceptual framework for developing novel therapeutic tools to mitigate aberrant fear responses in post traumatic stress disorder. In this review, we turn to the model of experience-dependent visual plasticity to provide novel insights for the mechanisms regulating plasticity in the fear system. Fear circuitry, particularly fear memory erasure, also undergoes age-related changes in experience-dependent plasticity. We consider the contributions of molecular brakes that halt visual critical period plasticity to circuitry underlying fear memory erasure. A major molecular brake in the visual cortex, perineuronal net formation, recently has been identified in the development of fear systems that are resilient to fear memory erasure. The roles of other molecular brakes, myelin-related Nogo receptor signaling and Lynx family proteins– endogenous inhibitors for nicotinic acetylcholine receptor, are explored in the context of fear memory plasticity. Such fear plasticity regulators, including epigenetic effects, provide promising targets for therapeutic interventions.
Cataclysmic Variables below the Period Gap: Mass Determinations of 14 Eclipsing Systems
Savoury, C D J; Dhillon, V S; Marsh, T R; Gaensicke, B T; Copperwheat, C M; Kerry, P; Hickman, R D G; Parsons, S G
2011-01-01
We present high-speed, three-colour photometry of the eclipsing cataclysmic variables CTCV 1300, CTCV 2354 and SDSS 1152. All three systems are below the observed "period gap" for cataclysmic variables. For each system we determine the system parameters by fitting a parameterised model to the observed eclipse light curve by chi-squared minimisation. We also present an updated analysis of all other eclipsing systems previously analysed by our group. New donor masses are generally between 1 and 2 sigma of those originally published, with the exception of SDSS 1502 and DV UMa. We note that the donor mass of SDSS 1501 has been revised upwards by 0.024Msun. This system was previously identified as having evolved passed the minimum orbital period for cataclysmic variables, but the new mass determination suggests otherwise. Our new analysis confirms that SDSS 1035 and SDSS 1433 have evolved past the period minimum for cataclysmic variables, corroborating our earlier studies. We find that the radii of donor stars are...
Chaotic dynamics of one-dimensional systems with periodic boundary conditions
Kumar, Pankaj; Miller, Bruce N.
2014-12-01
We provide appropriate tools for the analysis of dynamics and chaos for one-dimensional systems with periodic boundary conditions. Our approach allows for the investigation of the dependence of the largest Lyapunov exponent on various initial conditions of the system. The method employs an effective approach for defining the phase-space distance appropriate for systems with periodic boundaries and allows for an unambiguous test-orbit rescaling in the phase space required to calculate the Lyapunov exponents. We elucidate our technique by applying it to investigate the chaotic dynamics of a one-dimensional plasma with periodic boundaries. Exact analytic expressions are derived for the electric field and potential using Ewald sums, thereby making it possible to follow the time evolution of the plasma in simulations without any special treatment of the boundary. By employing a set of event-driven algorithms, we calculate the largest Lyapunov exponent, the radial distribution function, and the pressure by following the evolution of the system in phase space without resorting to numerical manipulation of the equations of motion. Simulation results are presented and analyzed for the one-dimensional plasma with a view to examining the dynamical and chaotic behavior exhibited by small and large versions of the system.
Chaotic dynamics of one-dimensional systems with periodic boundary conditions.
Kumar, Pankaj; Miller, Bruce N
2014-12-01
We provide appropriate tools for the analysis of dynamics and chaos for one-dimensional systems with periodic boundary conditions. Our approach allows for the investigation of the dependence of the largest Lyapunov exponent on various initial conditions of the system. The method employs an effective approach for defining the phase-space distance appropriate for systems with periodic boundaries and allows for an unambiguous test-orbit rescaling in the phase space required to calculate the Lyapunov exponents. We elucidate our technique by applying it to investigate the chaotic dynamics of a one-dimensional plasma with periodic boundaries. Exact analytic expressions are derived for the electric field and potential using Ewald sums, thereby making it possible to follow the time evolution of the plasma in simulations without any special treatment of the boundary. By employing a set of event-driven algorithms, we calculate the largest Lyapunov exponent, the radial distribution function, and the pressure by following the evolution of the system in phase space without resorting to numerical manipulation of the equations of motion. Simulation results are presented and analyzed for the one-dimensional plasma with a view to examining the dynamical and chaotic behavior exhibited by small and large versions of the system. PMID:25615175
Periodic and chaotic synchronizations of two distinct dynamical systems under sinusoidal constraints
International Nuclear Information System (INIS)
Highlights: ? Function synchronization of distinct dynamical systems. ? Synchronization onset and vanishing. ? Invariant sets of synchronization. ? Discontinuous dynamical systems. ? Synchronizations of pendulum and Duffing oscillator. - Abstract: In this paper, periodic and chaotic synchronizations between two distinct dynamical systems under specific constraints are investigated from the theory of discontinuous dynamical systems. The analytical conditions for the sinusoidal synchronization of the pendulum and Duffing oscillator were obtained, and the invariant domain of sinusoidal synchronization is achieved. From analytical conditions, the control parameter map is developed. Numerical illustrations for partial and full sinusoidal synchronizations of chaotic and periodic motions of the controlled pendulum with the Duffing oscillator are carried out. This paper presents how to apply the theory of discontinuous dynamical systems to dynamical system synchronization with specific constraints. The function synchronization of two distinct dynamical systems with specific constraints should be identified only by G-functions. The significance of function synchronization of distinct dynamical systems is to make the synchronicity behaviors hidden, which is very useful for telecommunication synchronization and network security.
Spectral validation of the Whitham equations for periodic waves of lattice dynamical systems
Kabil, Bu?ra; Rodrigues, L. Miguel
2016-02-01
In the present contribution we investigate some features of dynamical lattice systems near periodic traveling waves. First, following the formal averaging method of Whitham, we derive modulation systems expected to drive at main order the time evolution of slowly modulated wavetrains. Then, for waves whose period is commensurable to the lattice, we prove that the formally-derived first-order averaged system must be at least weakly hyperbolic if the background waves are to be spectrally stable, and, when weak hyperbolicity is met, the characteristic velocities of the modulation system provide group velocities of the original system. Historically, for dynamical evolutions obeying partial differential equations, this has been proved, according to increasing level of algebraic complexity, first for systems of reaction-diffusion type, then for generic systems of balance laws, at last for Hamiltonian systems. Here, for their semi-discrete counterparts, we give at once simultaneous proofs for all these cases. Our main analytical tool is the discrete Bloch transform, a discrete analogue to the continuous Bloch transform. Nevertheless, we needed to overcome the absence of genuine space-translation invariance, a key ingredient of continuous analyses.
Uniform exponential stability of linear almost periodic systems in Banach spaces
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David N. Cheban
2000-04-01
Full Text Available This article is devoted to the study linear non-autonomous dynamical systems possessing the property of uniform exponential stability. We prove that if the Cauchy operator of these systems possesses a certain compactness property, then the uniform asymptotic stability implies the uniform exponential stability. For recurrent (almost periodic systems this result is precised. We also show application for different classes of linear evolution equations: ordinary linear differential equations in a Banach space, retarded and neutral functional differential equations, and some classes of evolution partial differential equations.
Single thrust period missions to Uranus for unmanned nuclear-electric propulsion systems
Zola, C. L.
1973-01-01
The effects of trip time, propulsion time, and specific powerplant mass are studied for optimized unmanned probe spacecraft on missions to Uranus with nuclear-electric propulsion systems. Electric propulsion is confined to a single thrust period at the beginning of each mission. Mission profiles include both high-thrust and electric-propulsion Earth-departure modes for planet flyby and orbital capture. Effects of propulsion time and propulsion system parameters are evaluated, and typical design features of the nuclear-electric spacecraft are outlined. Payload capability comparisons are made with systems employing ballistic transfer and solar-electric propulsion.
Dimitrov, Dinko
2015-01-01
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.
Periodic and quasi-periodic motions of a solar sail close to SL 1 in the Earth-Sun system
Farrés, Ariadna; Jorba, Àngel
2010-06-01
Solar sails are a proposed form of spacecraft propulsion using large membrane mirrors to propel a satellite taking advantage of the solar radiation pressure. To model the dynamics of a solar sail we have considered the Earth-Sun Restricted Three Body Problem including the Solar radiation pressure (RTBPS). This model has a 2D surface of equilibrium points parametrised by the two angles that define the sail orientation. In this paper we study the non-linear dynamics close to an equilibrium point, with special interest in the bounded motion. We focus on the region of equilibria close to SL 1, a collinear equilibrium point that lies between the Earth and the Sun when the sail is perpendicular to the Sun-sail direction. For different fixed sail orientations we find families of planar, vertical and Halo-type orbits. We have also computed the centre manifold around different equilibria and used it to describe the quasi-periodic motion around them. We also show how the geometry of the phase space varies with the sail orientation. These kind of studies can be very useful for future mission applications.
Luo, Albert C. J.
2007-09-01
In the first part of this work, the local singularity of non-smooth dynamical systems was discussed and the criteria for the grazing bifurcation were presented mathematically. In this part, the fragmentation mechanism of strange attractors in non-smooth dynamical systems is investigated. The periodic motion transition is completed through grazing. The concepts for the initial and final grazing, switching manifolds are introduced for six basic mappings. The fragmentation of strange attractors in non-smooth dynamical systems is described mathematically. The fragmentation mechanism of the strange attractor for such a non-smooth dynamical system is qualitatively discussed. Such a fragmentation of the strange attractor is illustrated numerically. The criteria and topological structures for the fragmentation of the strange attractor need to be further developed as in hyperbolic strange attractors. The fragmentation of the strange attractors extensively exists in non-smooth dynamical systems, which will help us better understand chaotic motions in non-smooth dynamical systems.
Confrontation Between a Quantized Periods of Some Exo-planetary Systems and Observations
El Fady Morcos, Abd
2012-07-01
Confrontation Between a Quantized Periods of Some Exo-planetary Systems and Observations A.B. Morcos Corot and Kepler were designed to detect Earth-like extra solar planets. The orbital elements and periods of these planets will contain some uncertainties. Many theoretical treatments depend on the idea of quantization were done aiming to find orbital elements of these exoplenets. In the present work, as an extension of previous works, the periods of some extoplanetary systems are calculated by using a simple derived formula. The orbital velocities of some of them are predicted . A comparison between the calculated and observed data is done References 1-J.M. Barnothy , the stability of the Solar System and of small Stellar Systems . (Y.Kazai edn,IAU,1974). 2-L.Nottale,Fractal Space-Time and Microphysics,Towards a Theory of Scale Relativity,( World Scientific, London,1994). 3-L. Nottale, A&A Lett. 315, L9 (1996). 4-L. Nottale, G. Schumacher and J. Gay, A&A , 322, 1018 , (1997). 5-L. Nottale, A&A , 361, 379 (2000). 6-A.G. Agnese and R.Festa, arXiv:astro-ph/9807186v1, (1998). 7-A.G. Agnese and R.Festa, arXiv:astro-ph/9910534v2. (1999). 8- A.B.Morcos, MG 12 , France (2009). 9- A.B.Morcs, Cospar 38 , Bremen , Germany (2010)
Using sign patterns to detect the possibility of periodicity in biological systems.
Culos, G J; Olesky, D D; van den Driessche, P
2016-04-01
Many models in the physical and life sciences, formulated as dynamical systems, exhibit a positive steady state, with its local qualitative behavior determined by the eigenvalues of its Jacobian matrix. Our interest lies in detecting if this steady state is linearly stable or if the system has periodic solutions arising from a Hopf bifurcation. We address this by considering the sign pattern of the Jacobian matrix and its set of allowed refined inertias. The refined inertia of a matrix, which is an extension of the classical matrix inertia, is a property of its eigenvalues. A Hopf bifurcation, leading to periodic solutions, may be possible if the sign pattern of the Jacobian matrix allows a specific set of refined inertias. For most systems, we also need to consider magnitude restrictions on the entries of the Jacobian matrix that are a consequence of the particular biological model. The usefulness of sign pattern analysis to detect linear stability or the possibility of periodicity is illustrated with several biological examples, including metabolic-genetic circuits, biochemical reaction networks, predator-prey and competition systems. PMID:26092517
Dantas, Márcio José Horta; Sampaio, Rubens; Lima, Roberta
2016-02-01
In this work a class of time-periodic electromechanical system is investigated. This system is nonhyperbolic. By using Regular Perturbation Theory, results on existence and stability of periodic orbits are obtained. Moreover, the dynamics of this system can be approached in a mathematically rigorous way. These results generalize previous ones obtained for autonomous electromechanical systems.
Development of an arc-shaped precipitation system during the pre-monsoon period in Bangladesh
Rafiuddin, M.; Uyeda, Hiroshi; Kato, Masaya
2013-05-01
A numerical simulation is performed to understand the features and development processes of the arc-shaped precipitation system that dominates in Bangladesh during the pre-monsoon (March-May) period. An arc-shaped precipitation system of 26 April 2002 is simulated using the Cloud Resolving Storm Simulator (CReSS) with a horizontal grid increment of 2 km. The Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model is used for downscaling. Hourly outputs of the finest domain (grid increment of 5 km) of MM5 and National Oceanic and Atmospheric Administration Reynolds weekly mean sea surface temperature data are used as the initial and boundary conditions for CReSS. Younger and more intense cells are formed in the southwestern end of the system. These cells move northeastward and merge with the system producing intense rainfalls. Simulation results indicate that low-level southwesterly or southerly wind brings warm moist air from the Bay of Bengal and helps develop new cells. The propagation speed of the system is 8 m/s, and the northeastern end moves faster than the southwestern end, creating clockwise rotation of the system. The propagation speed and the rotation of the simulated system coincide well with radar observations. The clockwise rotation of the system can be explained by the stronger (weaker) outflow and weaker (stronger) inflow in the northeastern (southwestern) end. The propagation of the system is attributable to the weak (?7 m/s, storm relative) rear-to-front flow in the moist environment. Thus, the arc-shaped precipitation system common to the pre-monsoon period in Bangladesh develops through a balance of strong southwesterly or southerly moist inflow in the low altitudes below 2 km and relatively weak outflow in the rear of the system.
Spacecraft stability and control using new techniques for periodic and time-delayed systems
NAzari, Morad
This dissertation addresses various problems in spacecraft stability and control using specialized theoretical and numerical techniques for time-periodic and time-delayed systems. First, the effects of energy dissipation are considered in the dual-spin spacecraft, where the damper masses in the platform (?) and the rotor (?) cause energy loss in the system. Floquet theory is employed to obtain stability charts for different relative spin rates of the subsystem [special characters omitted] with respect to the subsystem [special characters omitted]. Further, the stability and bifurcation of delayed feedback spin stabilization of a rigid spacecraft is investigated. The spin is stabilized about the principal axis of the intermediate moment of inertia using a simple delayed feedback control law. In particular, linear stability is analyzed via the exponential-polynomial characteristic equations and then the method of multiple scales is used to obtain the normal form of the Hopf bifurcation. Next, the dynamics of a rigid spacecraft with nonlinear delayed multi-actuator feedback control are studied, where a nonlinear feedback controller using an inverse dynamics approach is sought for the controlled system to have the desired linear delayed closed-loop dynamics (CLD). Later, three linear state feedback control strategies based on Chebyshev spectral collocation and the Lyapunov Floquet transformation (LFT) are explored for regulation control of linear periodic time delayed systems. First , a delayed feedback control law with discrete delay is implemented and the stability of the closed-loop response is investigated in the parameter space of available control gains using infinite-dimensional Floquet theory. Second, the delay differential equation (DDE) is discretized into a large set of ordinary differential equations (ODEs) using the Chebyshev spectral continuous time approximation (CSCTA) and delayed feedback with distributed delay is applied. The third strategy involves use of both CSCTA and the reduced Lyapunov Floquet transformation (RLFT) in order to design a non-delayed feedback control law. The delayed Mathieu equation is used as an illustrative example in which the closed-loop response and control effort are compared for all three control strategies. Finally, three example applications of control of time-periodic astrodynamic systems, i.e. formation flying control for an elliptic Keplerian chief orbit, body-fixed hovering control over a tumbling asteroid, and stationkeeping in Earth-Moon L1 halo orbits, are shown using versions of the control strategies introduced above. These applications employ a mixture of feedforward and non-delayed periodic-gain state feedback for tracking control of natural and non-natural motions in these systems. A major conclusion is that control effort is minimized by employing periodic-gain (rather than constant-gain) feedback control in such systems.
Reverse resonance in stock prices of financial system with periodic information
Li, Jiang-Cheng; Mei, Dong-Cheng
2013-07-01
We investigate the stochastic resonance of the stock prices in a finance system with the Heston model. The extrinsic and intrinsic periodic information are introduced into the stochastic differential equations of the Heston model for stock price by focusing on the signal power amplification (SPA). We find that for both cases of extrinsic and intrinsic periodic information a phenomenon of reverse resonance emerges in the behaviors of SPA as a function of the system and external driving parameters. Moreover, in both cases, a phenomenon of double reverse resonance is observed in the behavior of SPA versus the amplitude of volatility fluctuations, by increasing the cross correlation between the noise sources in the Heston model.
Amplification Effects on the Transmission and Reflexion Phases in 1D Periodic Systems
Zekri, N; Maarouf, S
1999-01-01
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 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 whith increasing periods in the allowed band for the transmission phase while for the reflection phase, its initial value is always less than $\\pi /2$ in this band.
?azarski, Roman; Burow, Asbjörn M; Sierka, Marek
2015-07-14
An implementation of Kohn-Sham density functional theory within the TURBOMOLE program package with Gaussian-type orbitals (GTO) as basis functions is reported that treats molecular and periodic systems of any dimensionality on an equal footing. Its key component is a combination of density fitting/resolution of identity (DF) approximation and continuous fast multipole method (CFMM) applied for the electronic Coulomb term. This DF-CFMM scheme operates entirely in the direct space and partitions Coulomb interactions into far-field part evaluated using multipole expansions and near-field contribution calculated employing density fitting. Computational efficiency and favorable scaling behavior of our implementation approaching O(N) for the formation of Kohn-Sham matrix is demonstrated for various molecular and periodic systems including three-dimensional models with unit cells containing up to 640 atoms and 19072 GTO basis functions. PMID:26575740
A Hamiltonian-Free Description of Single Particle Dynamics for Hopelessly Complex Periodic Systems
Energy Technology Data Exchange (ETDEWEB)
Forest, E.
1990-01-01
We develop a picture of periodic systems which does not rely on the Hamiltonian of the system but on maps between a finite number of time locations. Moser or Deprit-like normalizations are done directly on the maps thereby avoiding the complex time-dependent theory. We redefine linear and nonlinear Floquet variables entirely in terms of maps. This approach relies heavily on the Lie representation of maps introduced by Dragt and Finn. One might say that although we do not use the Hamiltonian in the normalization transformation, we are using Lie operators which are themselves, in some sense, pseudo-Hamiltonians for the maps they represent. Our techniques find application in accelerator dynamics or in any field where the Hamiltonian is periodic but hopelessly complex, such as magnetic field design in stellarators.
The effect of traffic light on accident probability in open and periodic boundaries system
Mhirech, Abdelaziz; Alaoui-Ismaili, Assia
2015-09-01
In this paper we numerically study the dependence of car accident probability Pac, per site and per time step on cycle time T of traffic light, both in open and periodic boundaries system. In this study one traffic light is placed in the middle of the system. This work is based on Nagel and Schreckenberg (NaSch) model (Nagel and Schreckenberg (1992)) in parallel dynamics. The Pac dependence on T and the (?, ?) phase diagrams are established. ? and ? are the injecting and extracting rates of cars in the traffic lane respectively. The increase of the cycle time light T causes an important decrease of the accident probability Pac both in the open and periodic cases.
A Hamiltonian-free description of single particle dynamics for hopelessly complex periodic systems
Energy Technology Data Exchange (ETDEWEB)
Forest, E. (Exploratory Studies Group, Accelerator and Fusion Research Division, Lawrence Berkeley Laboratory, 1 Cyclotron Road, MS 47-112, Berkeley, California 94720 (USA))
1990-05-01
A picture of periodic systems that does not rely on the Hamiltonian of the system, but on maps between a finite number of time locations, is developed. Moser or Deprit-like normalizations are done directly on the maps, thereby avoiding the complex time-dependent theory. Linear and nonlinear Floquet variables are redefined entirely in terms of maps. This approach relies heavily on the Lie representation of maps introduced by Dragt and Finn (J. Math. Phys. {bold 20}, 2649 (1979); J. Geophys. Res. {bold 81}, 13 (1976)). One might say that although the Hamiltonian is not used in the normalization transformation, Lie operators are used, which are themselves, in some sense, pseudo-Hamiltonians for the maps they represent. The techniques find application in accelerator dynamics or in any field where the Hamiltonian is periodic, but hopelessly complex, such as magnetic field design in stellarators.
DEFF Research Database (Denmark)
Rudner, Mark Spencer; Lindner, Netanel; Berg, Erez; Levin, Michael
2013-01-01
revealed phenomena that cannot be characterized by analogy to the topological classification framework for static systems. In particular, in driven systems in two dimensions (2D), robust chiral edge states can appear even though the Chern numbers of all the bulk Floquet bands are zero. Here, we elucidate......Recently, several authors have investigated topological phenomena in periodically driven systems of noninteracting particles. These phenomena are identified through analogies between the Floquet spectra of driven systems and the band structures of static Hamiltonians. Intriguingly, these works have...... 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 â€œanomalous...
A case for shutdown cooling system exemption from the periodic inspection program
Energy Technology Data Exchange (ETDEWEB)
Handbury, J. [Canadian Power Utility Services Ltd., Toronto, Ontario (Canada)
2007-07-01
The Periodic Inspection Program (PIP) is conducted at CANDU stations to comply with the mandatory requirements in Canadian Standards Association (CSA) Standards N285.4, N285.5 and N287.7. A heavily-inspected system in this program is the Shutdown Cooling (SDC) System, which accounts for about 15% of the overall inspections. This paper presents a case to remove most of the SDC System from the PIP since the worst-case accident of the SDC System results in public radiological doses that are low enough to allow exemption under N285.4. This provides an opportunity for CANDU owners to inspect the SDC System on an owner-prescribed basis at their own schedule. This will reduce costs and personnel doses and allow the allocation of resources and funding to more safety-important inspections. (author)
Zhou, B.; Thouverez, F.; Lenoir, D.
2015-12-01
Quasi-periodic responses arise from various nonlinear dynamic systems under a single-frequency excitation. A variable-coefficient harmonic balance method is proposed for the prediction of quasi-periodic responses. The key point of this method is that the quasi-periodic response is described as a truncated trigonometric series with time-periodic Fourier coefficients. In other words, quasi-periodic responses are treated in a "cascade" of frequency base. Harmonic terms in the nonlinear system are separated and balanced with respect to each basic frequency. Numerical examples reveal that this method is efficient in predicting such quasi-periodic responses, which contain an unknown frequency component.
Non-periodic preventive maintenance with reliability thresholds for complex repairable systems
International Nuclear Information System (INIS)
In general, a non-periodic condition-based PM policy with different condition variables is often more effective than a periodic age-based policy for deteriorating complex repairable systems. In this study, system reliability is estimated and used as the condition variable, and three reliability-based PM models are then developed with consideration of different scenarios which can assist in evaluating the maintenance cost for each scenario. The proposed approach provides the optimal reliability thresholds and PM schedules in advance by which the system availability and quality can be ensured and the organizational resources can be well prepared and managed. The results of the sensitivity anlysis indicate that PM activities performed at a high reliability threshold can not only significantly improve the system availability but also efficiently extend the system lifetime, although such a PM strategy is more costly than that for a low reliabiltiy threshold. The optimal reliability threshold increases along with the number of PM activities to prevent future breakdowns caused by severe deterioration, and thus substantially reduces repair costs. - Highlights: â€¢ The PM problems for repairable deteriorating systems are formulated. â€¢ The structural properties of the proposed PM models are investigated. â€¢ The corresponding algorithms to find the optimal PM strategies are provided. â€¢ Imperfect PM activities are allowed to reduce the occurences of breakdowns. â€¢ Provide managers with insights about the critical factors in the planning stage
Anharmonic vibrational properties in periodic systems: energy, electron-phonon coupling, and stress
Monserrat, Bartomeu; Drummond, Neil; Needs, R. J.
2013-01-01
A unified approach is used to study vibrational properties of periodic systems with first-principles methods and including anharmonic effects. Our approach provides a theoretical basis for the determination of phonon-dependent quantities at finite temperatures. The low-energy portion of the Born-Oppenheimer energy surface is mapped and used to calculate the total vibrational energy including anharmonic effects, electron-phonon coupling, and the vibrational contribution to the stress tensor. W...
International Nuclear Information System (INIS)
The Green functions for an interacting fermion system which is coupled to a time periodic external field are defined and the most interesting properties of the on-particle Green functions are discussed. The general expression of the free one-particle Green function is derived and it is presented the perturbation theory with its diagrammatic interpretation for the evaluation of the interacting Green function. (author)
Time-periodic solutions to the full Navier–Stokes–Fourier system.
Czech Academy of Sciences Publication Activity Database
Feireisl, Eduard; Mucha, P.; Novotný, A.; Pokorný, M.
2012-01-01
Ro?. 204, ?. 3 (2012), s. 745-786. ISSN 0003-9527 R&D Projects: GA ?R GA201/09/0917; GA MŠk LC06052 Institutional research plan: CEZ:AV0Z10190503 Keywords : compressible Navier–Stokes–Fourier system * time-periodic solution * weak solution Subject RIV: BA - General Mathematics Impact factor: 2.292, year: 2012 http://www.springerlink.com/content/3t5r85w616158561/
Stochastic long term modelling of a drainage system with estimation of return period uncertainty
DEFF Research Database (Denmark)
Thorndahl, Søren
2009-01-01
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 confiden...
Infinite servers queue systems busy period - a practical case on logistics problems solving
Filipe, J. A.; Ferreira, Manuel Alberto M.
2015-01-01
In this paper it is exemplified how the busy period of an infinite servers queue is applied to the equipments failures management. With this model it is possible to obtain system performance measures and also to contribute to solve organizing structures’ problems, by minimizing the risks of the organizations inoperative structures, with considerable logistics pernicious consequences for companies and often also for the regions where the companies are inserted
Steffen, Jason H
2013-01-01
Many Kepler multiplanet systems have planet pairs near low-order, mean-motion resonances. In addition, many Kepler multiplanet systems have planets with orbital periods less than a few days. With the exception of Kepler-42, however, there are no examples of systems with both short orbital periods and nearby companion planets while our modeling predicts ~17 such pairs. For orbital periods of the inner planet that are less than three days, the minimum period ratio of adjacent planet pairs follows the rough constraint P_2/P_1 >~ 2.3 (P_1/day)^(-2/3). This excess is not due to a lack of planets with short orbital periods. We also show a statistically significant excess of small, single candidate systems with orbital periods below 3 days over the number of multiple candidate systems with similar periods---perhaps a small-planet counterpart to the hot Jupiters.
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 .
International Nuclear Information System (INIS)
Whereever non self-reporting faults have to be considered, (periodic) tests belong to the more important measures of reliability assurance. Although a general theory is still missing, the desired statements on mean time between failures and mean down time can be made for the important special case of exponential distribution of system's life. As examples the 1-out of-2- and the 2-out of-3-systems are treated extensively. (orig.)
International Nuclear Information System (INIS)
This paper deals with periodic solutions of the Hamilton equation x-dot (t)=J?x H(x(t),?), where H element of C2,0(R2n×Rk,R) and ? element of Rk is a parameter. Theorems on global bifurcation of solutions with periods (2?)/j, j element of N, from a stationary point (x0,?0) element of R2n×Rk are proved. ?x2 H(x0,?0) can be singular. However, it is assumed that the local topological degree of ?xH(·, ?0) at x0 is nonzero. For systems satisfying ?xH(x0, ?) = 0 for all ? element of Rk it is shown that (global) bifurcation points of solutions with periods (2?)/j can be identified with zeros of appropriate continuous functions Fj:Rk?R. If, for all ? element of Rk, ?x2H(x0,?)=diag(A(?),B(?)), where A(?) and B(?) are (n × n)-matrices, then Fj can be defined by Fj(?) = det[A(?)B(?) ? j2I]. Symmetry breaking results concerning bifurcation of solutions with different minimal periods are obtained. A geometric description of the set of bifurcation points is given. Examples of constructive application of the theorems proved to analytical and numerical investigation and visualization of the set of all bifurcation points in given domain are provided. This paper is based on a part of the author's thesis (Radzki 2005 Branching points of periodic solutions of autonomous Hamiltonian systems (Polish) PhD Thesis Nicolaus Copernicus University, Faculty of Mathematics and Computer Science, Toru?)
Multi-Period Optimization for Voltage Control System in Transmission Grids
DEFF Research Database (Denmark)
Qin, Nan; Chen, Si; Liu, Chengxi; Abildgaard, Hans; Bak, Claus Leth; Chen, Zhe
Automatic Voltage Control (AVC) systems maintain the voltage in an acceptable range and minimize the power loss of the grid by coordinately regulating the controllable components. Switchable shunts and tap-able transformers are expected to be operated as few times as possible. This paper proposes a...... the lower level, the optimization is focused on the correction of the voltage violations every single minute based on data from the measurements and state estimation. The presented case study shows that the multi-period optimization in the upper level of AVC system can reduce adjustment times of the...
Calculation of electron density of periodic systems using non-orthogonal localised orbitals
Kantorovich, L; Kantorovich, Lev; Danyliv, Oleh
2004-01-01
Methods for calculating an electron density of a periodic crystal constructed using non-orthogonal localised orbitals are discussed. We demonstrate that an existing method based on the matrix expansion of the inverse of the overlap matrix into a power series can only be used when the orbitals are highly localised (e.g. ionic systems). In other cases including covalent crystals or those with an intermediate type of chemical bonding this method may be either numerically inefficient or fail altogether. Instead, we suggest an exact and numerically efficient method which can be used for orbitals of practically arbitrary localisation. Theory is illustrated by numerical calculations on a model system.
International Nuclear Information System (INIS)
The study on the electron beam generation processes in the system of the magnetron guns with the secondary-emission cathodes and anodes in form of periodically positioned metallic pins is carried out. It is shown, that the beam summary current of approximately 22 A is obtained in the system, consisting of four cells, which corresponds to the quadruplicate beam current value of the one cell. The pulse capacity thereby constituted approximately 600 kW. Such beams may be applied in the multipulse microwave devices
Ajzatskij, N I; Zakutin, V V; Reshetnyak, N G; Romasko, V P; Volkolupov, Yu Ya; Krasnogolovets, M A
2001-01-01
The study on the electron beam generation processes in the system of the magnetron guns with the secondary-emission cathodes and anodes in form of periodically positioned metallic pins is carried out. It is shown, that the beam summary current of approximately 22 A is obtained in the system, consisting of four cells, which corresponds to the quadruplicate beam current value of the one cell. The pulse capacity thereby constituted approximately 600 kW. Such beams may be applied in the multipulse microwave devices
Dynamical tunneling of a Bose-Einstein condensate in periodically driven systems
Shrestha, R. K.; Ni, J.; Lam, W. K.; Summy, G. S.; Wimberger, S.
2013-09-01
We report measurements of dynamical tunneling rates of a Bose-Einstein condensate across a barrier in classical phase space. The atoms are initially prepared in quantum states that extend over a classically regular island region. We focus on the specific system of quantum accelerator modes of the kicked rotor in the presence of gravity. Our experimental data is supported by numerical simulations taking into account imperfections mainly from spontaneous emission. Furthermore, we predict experimentally accessible parameter ranges over which direct tunneling could be readily observed if spontaneous emission was further suppressed. Altogether, we provide a proof-of-principle for the experimental accessibility of dynamical tunneling rates in periodically driven systems.
Periodic Density Modulation Effects on a Correlated two-dimensional Composite Fermion System
Sakhi, S
2001-01-01
We examine theoretically the effects caused by a periodic external potential on the correlated motion of a two-dimensional electron system under strong magnetic fields corresponding to a filling factor 1/2. To describe the resulting complex dynamics, we adopt a composite fermion approach and we determine in a two loop approximation the density-response function $K_{00}(\\bfq,\\omega)$ and the compressibility. We show explicitly that the long-wavelength limit of $K_{00}(\\bfq,\\omega)$ exhibits substantial anisotropic behavior induced by the modulation, and that the system tends to be incompressible in a direction orthogonal to the modulation as opposed to its response along the modulation.
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)
Markov analysis of redundant standby safety systems under periodic surveillance testing
International Nuclear Information System (INIS)
In modern applications of probabilistic safety assessment (PSA), maintenance planning and changes to technical specifications play an important role, not least due to regulatory requirements. In particular, standby safety systems under periodic surveillance testing are at the center of this issue. Since traditional PSA techniques impose limitations when complex maintenance and repair strategies are to be taken explicitly into account, we introduce continuous time Markov models to discuss various strategies for organizing repair and testing of two-train standby safety systems, which have the potential to replace traditional system models based on fault tree techniques in PSA. Besides a conventional steady state analysis of these Markov models, we provide a general numerical method which allows the calculation of the probability of exceeding allowed outage times of equipment in Markov models of safety systems, and we apply it to the models introduced in the present paper. - Highlights: • We consider Markov models of systems under periodic surveillance testing. • Besides the steady state availability we consider the probability of exceeding allowed outage times of equipment. • We provide a general method to calculate the probability of exceeding allowed outage times for Markov models
Minimisation of Non-periodic Preventive Maintenance Cost in Series-Parallel Systems
Directory of Open Access Journals (Sweden)
Te-Wei Lin
2011-01-01
Full Text Available A new method to optimise the non-periodic preventive maintenance model of a series-parallel system is proposed. A two-stage algorithm that incorporates the failure limit policy to determine maintenance components, maintenance times, and total maintenance cost is suggested. When the reliability of the system reaches a threshold value, preventive maintenance is performed. The first stage identifies the parallel subsystem required to be maintained, while the second stage determines the component required to be maintained in the parallel sub-system. A unit-cost life index (UCL has been developed to evaluate the extent to which maintaining a component extends the life of a system for the parallel subsystem. Three simulated cases demonstrate the effectiveness and the practicality of the proposed method in optimising the non-periodic preventive maintenance model of a series-parallel system.Defence Science Journal, 2011, 61(1, pp.44-50, DOI:http://dx.doi.org/10.14429/dsj.61.61
Oliver Sacks in Mendeleev's Garden
Marshall, James L.
2003-08-01
After returning to New York, Oliver Sacks sent to us a preprint of Uncle Tungsten, which we had the pleasure of perusing for a whole year before publication. After the events of September 11, 2001, my wife and I anxiously awaited word that he was all right. We were relieved—and honored—when in early December we received an autographed copy of Uncle Tungsten (3). We will always treasure Oliver Sacks’s book, his remarkable story of chemistry, and our friendship with him.
Hayashi, K; Hayashi, Kumiko; Sasa, Sin-ichi
2004-01-01
We theoretically study Langevin systems with a tilted periodic potential. It has been known that the ratio $\\Theta$ of the diffusion constant to the differential mobility is not equal to the temperature of the environment (multiplied by the Boltzmann constant), except in the linear response regime, where the fluctuation dissipation theorem holds. In order to elucidate the physical meaning of $\\Theta$ far from equilibrium, we analyze a modulated system with a slowly varying potential. We derive a large scale description of the probability density for the modulated system by use of a perturbation method. The expressions we obtain show that $\\Theta$ plays the role of the temperature in the large scale description of the system and that $\\Theta$ can be determined directly in experiments, without measurements of the diffusion constant and the differential mobility.
Inventory of thermal solar energy systems in the Netherlands: Period 1975-1992
International Nuclear Information System (INIS)
An overview is given of the number of active thermal solar energy systems that have been installed in the Netherlands during the period 1975-1992. By the end of 1992, 8,300 systems have been installed, of which 6,000 were domestic solar hot water systems. The uncertainty in these figures is 10%. Several sources were used to determine the number of systems installed. The two main sources were the files of the solar industry association 'Holland Solar' (data until 1988), and the Dutch subsidy administrator 'Senter' for data from 1988 up to and including 1992. At the end of 1992 preparations were made for the installation of approximately 3,000 domestic solar water heaters in 1993. It is recommended to carry out an inventory every three months and to compile data on investment costs. 17 figs., 7 appendices
International Nuclear Information System (INIS)
A comprehensive presentation of a new approach to finite periodic systems is given. The novel and general expressions obtained here, allow simple and precise calculations of various physical quantities characteristic of crystalline systems. Transmission amplitudes through n-cell multichannel quantum systems are rigorously derived. General expressions for several physical quantities are entirely expressed in terms of single-cell amplitudes and a new class of polynomials pN,n. Besides the general expressions, we study some superlattice properties as the band structure and its relation with the phase coherence phenomena, the level density and the Kronig-Penney model as its continuous espectrum limit. Bandstructure tailoring, optical multilayer systems, resonant energies and functions and channel-mixing effects in multichannel transport process are also analysed in the light of the new approach. (author)
Endoscopic system for automated high dynamic range inspection of moving periodic structures
Hahlweg, Cornelius; Rothe, Hendrik
2015-09-01
In the current paper an advanced endoscopic system for high resolution and high dynamic range inspection of periodic structures in rotating machines is presented. We address the system architecture, short time illumination, special optical problems, such as excluding the specular reflex, image processing, forward velocity prediction and metrological image processing. There are several special requirements to be met, such as the thermal stability above 100°C, robustness of the image field, illumination in view direction and the separation of metallic surface diffuse scatter. To find a compromise between image resolution and frame rate, an external sensor system was applied for synchronization with the moving target. The system originally was intended for inspection of thermal engines, but turned out to be of a more general use. Beside the theoretical part and dimensioning issues, practical examples and measurement results are included.
Residual currents in a multiple-inlet system and the conundrum of the tidal period
Duran-Matute, Matias; Gerkema, Theo
2015-04-01
In multiple-inlet systems, one may find that, on average, flood dominates in some inlets, while ebb dominates in others. In that case, there is a residual flow through the system, i.e. there is a net flow if one integrates over a tidal period. Conceptually, this seems straightforward. However, to measure such a residual flow presents several difficulties. First, one needs to cover the entire cross-sections of all the inlets over a year or longer to take into account the variability due to wind. Second, the residual flow is usually much smaller than the tidal prisms and hence more uncertain in view of error bars. Third, the duration of 'the' tidal period when calculating a tidally averaged flow is not well defined. Should one take the time between alternate slack tides, or between consecutive high (or low) waters, or other options? There appears to be a fundamental ambiguity in the duration of the tidal period; here we discuss its origins. The problem of defining the tidal period seems to have received little attention in the literature, or perhaps it has not been perceived as a problem at all. One reason for this neglect may be that the focus in tidal analysis is often on the (main) individual tidal constituents, whose periods are well-defined. Indeed, the harmonic method developed by Kelvin exploits this fact, making it possible to predict high and low waters precisely by adding up the different constituents after their amplitudes and phases have been determined empirically for the location in question. The period between subsequent high (or low) waters is then simply an outcome of this method. Another reason for neglecting this problem may be that the main interest was in computing a representative quantity such as the yearly average residual flow through the inlets. For such quantities, the definition of the tidal period is not as relevant since one integrates over a much longer period. Recently, however, it has been shown, for the Western Dutch Wadden Sea, that the yearly average transport is not representative of typical conditions (Duran-Matute et al. 2014), since the residual circulation has a strongly episodic character due to wind variability. This puts the focus again on the shorter time-scales of these episodes. Hence the central point of this presentation: to examine how the mean, median and the standard deviation of residual flows depend on how one defines the tidal period. We offer an alterative definition that is particularly suitable on a basin-wide scale. In this presentation we focus on the residual transport of water itself, but the relevance of the problem at hand extends directly to residual transports of sediment, nutrients, pollutants, etc., in multiple-inlet systems.
'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)
Fast and spectrally accurate Ewald summation for 2-periodic electrostatic systems
Lindbo, Dag
2011-01-01
A new method for Ewald summation in planar/slablike geometry, i.e. systems where periodicity applies in two dimensions and the last dimension is "free" (2P), is presented. We employ a spectral representation in terms of both Fourier series and integrals. This allows us to concisely derive both the 2P Ewald sum and a fast PME-type method suitable for large-scale computations. The primary results are: (i) close and illuminating connections between the 2P problem and the standard Ewald sum and associated fast methods for full periodicity; (ii) a fast, O(N log N), and spectrally accurate PME-type method for the 2P k-space Ewald sum that uses vastly less memory than traditional PME methods; (iii) errors that decouple, such that parameter selection is simplified. We give analytical and numerical results to support this.
Fast and spectrally accurate Ewald summation for 2-periodic electrostatic systems
Lindbo, Dag; Tornberg, Anna-Karin
2012-04-01
A new method for Ewald summation in planar/slablike geometry, i.e., systems where periodicity applies in two dimensions and the last dimension is "free" (2P), is presented. We employ a spectral representation in terms of both Fourier series and integrals. This allows us to concisely derive both the 2P Ewald sum and a fast particle mesh Ewald (PME)-type method suitable for large-scale computations. The primary results are: (i) close and illuminating connections between the 2P problem and the standard Ewald sum and associated fast methods for full periodicity; (ii) a fast, O(N log N), and spectrally accurate PME-type method for the 2P k-space Ewald sum that uses vastly less memory than traditional PME methods; (iii) errors that decouple, such that parameter selection is simplified. We give analytical and numerical results to support this.
Analysis of Financial Performance in the Banking System in Kosovo - the Period 2006 - 2012
Directory of Open Access Journals (Sweden)
Skender Ahmeti
2014-04-01
Full Text Available Through this paper we analyse the performance indicators of banks in Kosovo Banking System. According to the works of different authors worldwide, more accurate measurement of bank performance based on accounting data, in the application of coefficients leading financial banks are: Return on assets - ROA, return on equity - ROE and Cost Report to revenue - C / I. This paper describes the analysis of financial indicators for the period 2006 – 2007 – 2008 – 2009 -2010 - 2011 and 2012. The paper is organized as follows: - Section 2 provides literature review on the performance of banks in other countries; - Section 3 provides an analysis of the banking sector in Kosovo and macroeconomic indicators during the period analysed; - Section 4 presents the results of analysing the financial coefficients. While section 5 presents financial analysis and provides key conclusions.
1/1 resonant periodic orbits in three dimensional planetary systems
Antoniadou, Kyriaki I; Varvoglis, Harry
2014-01-01
We study the dynamics of a two-planet system, which evolves being in a $1/1$ mean motion resonance (co-orbital motion) with non-zero mutual inclination. In particular, we examine the existence of bifurcations of periodic orbits from the planar to the spatial case. We find that such bifurcations exist only for planetary mass ratios $\\rho=\\frac{m_2}{m_1}<0.0205$. For $\\rho$ in the interval $0<\\rho<0.0205$, we compute the generated families of spatial periodic orbits and their linear stability. These spatial families form bridges, which start and end at the same planar family. Along them the mutual planetary inclination varies. We construct maps of dynamical stability and show the existence of regions of regular orbits in phase space.
Quantum Intermittency in Almost-Periodic Lattice Systems Derived from their Spectral Properties
Mantica, G
1996-01-01
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.
Reliability of unstable periodic orbit based control strategies in biological systems
Energy Technology Data Exchange (ETDEWEB)
Mishra, Nagender; Singh, Harinder P. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Hasse, Maria [Institut fÃ¼r HÃ¶chstleistungsrechnen, UniversitÃ¤t Stuttgart, D-70569 Stuttgart (Germany); Biswal, B. [Cluster Innovation Center, University of Delhi, Delhi 110007 (India); Sri Venkateswara College, University of Delhi, Delhi 110021 (India)
2015-04-15
Presence of recurrent and statistically significant unstable periodic orbits (UPOs) in time series obtained from biological systems is now routinely used as evidence for low dimensional chaos. Extracting accurate dynamical information from the detected UPO trajectories is vital for successful control strategies that either aim to stabilize the system near the fixed point or steer the system away from the periodic orbits. A hybrid UPO detection method from return maps that combines topological recurrence criterion, matrix fit algorithm, and stringent criterion for fixed point location gives accurate and statistically significant UPOs even in the presence of significant noise. Geometry of the return map, frequency of UPOs visiting the same trajectory, length of the data set, strength of the noise, and degree of nonstationarity affect the efficacy of the proposed method. Results suggest that establishing determinism from unambiguous UPO detection is often possible in short data sets with significant noise, but derived dynamical properties are rarely accurate and adequate for controlling the dynamics around these UPOs. A repeat chaos control experiment on epileptic hippocampal slices through more stringent control strategy and adaptive UPO tracking is reinterpreted in this context through simulation of similar control experiments on an analogous but stochastic computer model of epileptic brain slices. Reproduction of equivalent results suggests that far more stringent criteria are needed for linking apparent success of control in such experiments with possible determinism in the underlying dynamics.
Self-consistent second-order Green's function perturbation theory for periodic systems.
Rusakov, Alexander A; Zgid, Dominika
2016-02-01
Despite recent advances, systematic quantitative treatment of the electron correlation problem in extended systems remains a formidable task. Systematically improvable Green's function methods capable of quantitatively describing weak and at least qualitatively strong correlations appear as promising candidates for computational treatment of periodic systems. We present a periodic implementation of temperature-dependent self-consistent 2nd-order Green's function (GF2) method, where the self-energy is evaluated in the basis of atomic orbitals. Evaluating the real-space self-energy in atomic orbitals and solving the Dyson equation in k-space are the key components of a computationally feasible algorithm. We apply this technique to the one-dimensional hydrogen lattice - a prototypical crystalline system with a realistic Hamiltonian. By analyzing the behavior of the spectral functions, natural occupations, and self-energies, we claim that GF2 is able to recover metallic, band insulating, and at least qualitatively Mott regimes. We observe that the iterative nature of GF2 is essential to the emergence of the metallic and Mott phases. PMID:26851907
Reliability of unstable periodic orbit based control strategies in biological systems.
Mishra, Nagender; Hasse, Maria; Biswal, B; Singh, Harinder P
2015-04-01
Presence of recurrent and statistically significant unstable periodic orbits (UPOs) in time series obtained from biological systems is now routinely used as evidence for low dimensional chaos. Extracting accurate dynamical information from the detected UPO trajectories is vital for successful control strategies that either aim to stabilize the system near the fixed point or steer the system away from the periodic orbits. A hybrid UPO detection method from return maps that combines topological recurrence criterion, matrix fit algorithm, and stringent criterion for fixed point location gives accurate and statistically significant UPOs even in the presence of significant noise. Geometry of the return map, frequency of UPOs visiting the same trajectory, length of the data set, strength of the noise, and degree of nonstationarity affect the efficacy of the proposed method. Results suggest that establishing determinism from unambiguous UPO detection is often possible in short data sets with significant noise, but derived dynamical properties are rarely accurate and adequate for controlling the dynamics around these UPOs. A repeat chaos control experiment on epileptic hippocampal slices through more stringent control strategy and adaptive UPO tracking is reinterpreted in this context through simulation of similar control experiments on an analogous but stochastic computer model of epileptic brain slices. Reproduction of equivalent results suggests that far more stringent criteria are needed for linking apparent success of control in such experiments with possible determinism in the underlying dynamics. PMID:25933652
Reliability of unstable periodic orbit based control strategies in biological systems
International Nuclear Information System (INIS)
Presence of recurrent and statistically significant unstable periodic orbits (UPOs) in time series obtained from biological systems is now routinely used as evidence for low dimensional chaos. Extracting accurate dynamical information from the detected UPO trajectories is vital for successful control strategies that either aim to stabilize the system near the fixed point or steer the system away from the periodic orbits. A hybrid UPO detection method from return maps that combines topological recurrence criterion, matrix fit algorithm, and stringent criterion for fixed point location gives accurate and statistically significant UPOs even in the presence of significant noise. Geometry of the return map, frequency of UPOs visiting the same trajectory, length of the data set, strength of the noise, and degree of nonstationarity affect the efficacy of the proposed method. Results suggest that establishing determinism from unambiguous UPO detection is often possible in short data sets with significant noise, but derived dynamical properties are rarely accurate and adequate for controlling the dynamics around these UPOs. A repeat chaos control experiment on epileptic hippocampal slices through more stringent control strategy and adaptive UPO tracking is reinterpreted in this context through simulation of similar control experiments on an analogous but stochastic computer model of epileptic brain slices. Reproduction of equivalent results suggests that far more stringent criteria are needed for linking apparent success of control in such experiments with possible determinism in the underlying dynamics
Statistics of Long Period Gas Giant Planets in Known Planetary Systems
Bryan, Marta L; Howard, Andrew W; Ngo, Henry; Batygin, Konstantin; Crepp, Justin R; Fulton, B J; Hinkley, Sasha; Isaacson, Howard; Johnson, John A; Marcy, Geoffry W; Wright, Jason T
2016-01-01
We conducted a Doppler survey at Keck combined with NIRC2 K-band AO imaging to search for massive, long-period companions to 123 known exoplanet systems with one or two planets detected using the radial velocity (RV) method. Our survey is sensitive to Jupiter mass planets out to 20 AU for a majority of stars in our sample, and we report the discovery of eight new long-period planets, in addition to 20 systems with statistically significant RV trends indicating the presence of an outer companion beyond 5 AU. We combine our RV observations with AO imaging to determine the range of allowed masses and orbital separations for these companions, and account for variations in our sensitivity to companions among stars in our sample. We estimate the total occurrence rate of companions in our sample to be 52 +/- 5% over the range 1 - 20 M_Jup and 5 - 20 AU. Our data also suggest a declining frequency for gas giant planets in these systems beyond 3-10 AU, in contrast to earlier studies that found a rising frequency for g...
Bayard, David S.
1994-03-01
Periodic gain adjustment in plants of irreducible order, n, or for equalization of communications channels is effected in such a way that the plant (system) appears to be minimum phase by choosing a horizon time N is greater than n of liftings in periodic input and output windows rho sub u and rho sub y, respectively, where N is an integer chosen to define the extent (length) of each of the windows rho sub u and rho sub y, and n is the order of an irreducible input/output plant. The plant may be an electrical, mechanical, or chemical system, in which case output tracking (OT) is carried out for feedback control or a communication channel, in which case input tracking (IT) is performed. Conditions for OT are distinct from IT in terms of zero annihilation, namely H(sub s)H(sub s)(sup +) = I for OT and H(sub s)H(sub s)(sup +) = I of IT, where the OT conditions are intended for gain adjustments in the control system, and IT conditions are intended for equalization for communication channels.
Self-consistent second-order Green's function perturbation theory for periodic systems
Rusakov, Alexander A.; Zgid, Dominika
2016-02-01
Despite recent advances, systematic quantitative treatment of the electron correlation problem in extended systems remains a formidable task. Systematically improvable Green's function methods capable of quantitatively describing weak and at least qualitatively strong correlations appear as promising candidates for computational treatment of periodic systems. We present a periodic implementation of temperature-dependent self-consistent 2nd-order Green's function (GF2) method, where the self-energy is evaluated in the basis of atomic orbitals. Evaluating the real-space self-energy in atomic orbitals and solving the Dyson equation in k-space are the key components of a computationally feasible algorithm. We apply this technique to the one-dimensional hydrogen lattice — a prototypical crystalline system with a realistic Hamiltonian. By analyzing the behavior of the spectral functions, natural occupations, and self-energies, we claim that GF2 is able to recover metallic, band insulating, and at least qualitatively Mott regimes. We observe that the iterative nature of GF2 is essential to the emergence of the metallic and Mott phases.
The Metals in the Biological Periodic System of the Elements: Concepts and Conjectures
Directory of Open Access Journals (Sweden)
Wolfgang Maret
2016-01-01
Full Text Available A significant number of chemical elements are either essential for life with known functions, or present in organisms with poorly defined functional outcomes. We do not know all the essential elements with certainty and we know even less about the functions of apparently non-essential elements. In this article, I discuss a basis for a biological periodic system of the elements and that biochemistry should include the elements that are traditionally part of inorganic chemistry and not only those that are in the purview of organic chemistry. A biological periodic system of the elements needs to specify what “essential” means and to which biological species it refers. It represents a snapshot of our present knowledge and is expected to undergo further modifications in the future. An integrated approach of biometal sciences called metallomics is required to understand the interactions of metal ions, the biological functions that their chemical structures acquire in the biological system, and how their usage is fine-tuned in biological species and in populations of species with genetic variations (the variome.
The Metals in the Biological Periodic System of the Elements: Concepts and Conjectures.
Maret, Wolfgang
2016-01-01
A significant number of chemical elements are either essential for life with known functions, or present in organisms with poorly defined functional outcomes. We do not know all the essential elements with certainty and we know even less about the functions of apparently non-essential elements. In this article, I discuss a basis for a biological periodic system of the elements and that biochemistry should include the elements that are traditionally part of inorganic chemistry and not only those that are in the purview of organic chemistry. A biological periodic system of the elements needs to specify what "essential" means and to which biological species it refers. It represents a snapshot of our present knowledge and is expected to undergo further modifications in the future. An integrated approach of biometal sciences called metallomics is required to understand the interactions of metal ions, the biological functions that their chemical structures acquire in the biological system, and how their usage is fine-tuned in biological species and in populations of species with genetic variations (the variome). PMID:26742035
Reliability of unstable periodic orbit based control strategies in biological systems
Mishra, Nagender; Hasse, Maria; Biswal, B.; Singh, Harinder P.
2015-04-01
Presence of recurrent and statistically significant unstable periodic orbits (UPOs) in time series obtained from biological systems is now routinely used as evidence for low dimensional chaos. Extracting accurate dynamical information from the detected UPO trajectories is vital for successful control strategies that either aim to stabilize the system near the fixed point or steer the system away from the periodic orbits. A hybrid UPO detection method from return maps that combines topological recurrence criterion, matrix fit algorithm, and stringent criterion for fixed point location gives accurate and statistically significant UPOs even in the presence of significant noise. Geometry of the return map, frequency of UPOs visiting the same trajectory, length of the data set, strength of the noise, and degree of nonstationarity affect the efficacy of the proposed method. Results suggest that establishing determinism from unambiguous UPO detection is often possible in short data sets with significant noise, but derived dynamical properties are rarely accurate and adequate for controlling the dynamics around these UPOs. A repeat chaos control experiment on epileptic hippocampal slices through more stringent control strategy and adaptive UPO tracking is reinterpreted in this context through simulation of similar control experiments on an analogous but stochastic computer model of epileptic brain slices. Reproduction of equivalent results suggests that far more stringent criteria are needed for linking apparent success of control in such experiments with possible determinism in the underlying dynamics.
Rousselet, Bernard
2013-01-01
We consider {\\it small solutions} of a vibrating mechanical system with smooth non-linearities for which we provide an approximate solution by using a triple scale analysis; a rigorous proof of convergence of the triple scale method is included; for the forced response, a stability result is needed in order to prove convergence in a neighbourhood of a primary resonance. The amplitude of the response with respect to the frequency forcing is described and it is related to the frequency of a free periodic vibration.
Anharmonic vibrational properties in periodic systems: energy, electron-phonon coupling, and stress
Monserrat, Bartomeu; Drummond, N. D.; Needs, R. J.
2013-04-01
A unified approach is used to study vibrational properties of periodic systems with first-principles methods and including anharmonic effects. Our approach provides a theoretical basis for the determination of phonon-dependent quantities at finite temperatures. The low-energy portion of the Born-Oppenheimer energy surface is mapped and used to calculate the total vibrational energy including anharmonic effects, electron-phonon coupling, and the vibrational contribution to the stress tensor. We report results for the temperature dependence of the electronic band gap and the linear coefficient of thermal expansion of diamond, lithium hydride, and lithium deuteride.
Nontrivial periodic solutions of nonlinear functional differential systems with feedback control
GUO, Yingxin
2010-01-01
This paper examines the existence of nontrivial periodic solutions for the nonlinear functional differential system with feedback control: \\{\\aligned x'(t)=x(t)a(t)-\\big[\\sumi=1n ai(t)\\int0+\\infty f(t, x(t-q)) d}ji(q) +\\sumj=1m bj(t) \\int0+\\infty f(t,x'(t-q))\\,d}fj(q)+\\summ=1p c\\mu(t) \\int0\\infty u(t-q)\\,d}d\\mu(q)\\big], u'(t)=-r(t)u(t)+\\sumn=1q b\
Surface N Balances in Agricultural Crop production systems in China for the period 1980-2015
Sun, B.; Shen, R.P.; A. F. Bouwman
2008-01-01
Surface nitrogen (N) balances for China's crop production systems were estimated using statistical data collected from 1980 to 2004 at the national and provincial scale and from 1994 to 1999 at the county level. There was a surplus N balance throughout these periods, but the surplus was nearly 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 ...
Thermodynamics of Micro- and Nano-Systems Driven by Periodic Temperature Variations
Brandner, Kay; Saito, Keiji; Seifert, Udo
2015-07-01
We introduce a general framework for analyzing the thermodynamics of small systems that are driven by both a periodic temperature variation and some external parameter modulating their energy. This setup covers, in particular, periodic micro- and nano-heat engines. In a first step, we show how to express total entropy production by properly identified time-independent affinities and currents without making a linear response assumption. In linear response, kinetic coefficients akin to Onsager coefficients can be identified. Specializing to a Fokker-Planck-type dynamics, we show that these coefficients can be expressed as a sum of an adiabatic contribution and one reminiscent of a Green-Kubo expression that contains deviations from adiabaticity. Furthermore, we show that the generalized kinetic coefficients fulfill an Onsager-Casimir-type symmetry tracing back to microscopic reversibility. This symmetry allows for nonidentical off-diagonal coefficients if the driving protocols are not symmetric under time reversal. We then derive a novel constraint on the kinetic coefficients that is sharper than the second law and provides an efficiency-dependent bound on power. As one consequence, we can prove that the power vanishes at least linearly when approaching Carnot efficiency. We illustrate our general framework by explicitly working out the paradigmatic case of a Brownian heat engine realized by a colloidal particle in a time-dependent harmonic trap subject to a periodic temperature profile. This case study reveals inter alia that our new general bound on power is asymptotically tight.
Buying Timeâ€”The Immune System Determinants of the Incubation Period to Respiratory Viruses
Directory of Open Access Journals (Sweden)
Thomas M. Moran
2010-11-01
Full Text Available Respiratory viruses cause disease in humans characterized by an abrupt onset of symptoms. Studies in humans and animal models have shown that symptoms are not immediate and appear days or even weeks after infection. Since the initial symptoms are a manifestation of virus recognition by elements of the innate immune response, early virus replication must go largely undetected. The interval between infection and the emergence of symptoms is called the incubation period and is widely used as a clinical score. While incubation periods have been described for many virus infections the underlying mechanism for this asymptomatic phase has not been comprehensively documented. Here we review studies of the interaction between human pathogenic respiratory RNA viruses and the host with a particular emphasis on the mechanisms used by viruses to inhibit immunity. We discuss the concept of the â€œstealth phaseâ€, defined as the time between infection and the earliest detectable inflammatory response. We propose that the â€œstealth phaseâ€ 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.
International Nuclear Information System (INIS)
A great effort has been made to improve the nuclear plant control system by use of digital technologies and a long term schedule for the control system upgrade has been prepared with an aim to implementation in the next generation nuclear plants. In case of digital control system, it is important to decide the sampling period for analysis and design of the system, because the performance and the stability of a digital control system depend on the value of the sampling period of the digital control system. There is, however, currently no systematic method used universally for determining the sampling period of the digital control system. Generally, a traditional way to select the sampling frequency is to use 20 to 30 times the bandwidth of the analog control system which has the same system configuration and parameters as the digital one. In this paper, a new method to select the sampling period is suggested which takes into account of the performance as well as the stability of the digital control system. By use of the Irving's model steam generator, the optimal sampling period of an assumptive digital control system for steam generator level control is estimated and is actually verified in the digital control simulation system for Kori-2 nuclear power plant steam generator level control. Consequently, we conclude the optimal sampling period of the digital control system for Kori-2 nuclear power plant steam generator level control is 1 second for all power ranges. 7 figs., 3 tabs., 8 refs. (Author)
Johnson, Mathew A.; Zumbrun, Kevin
2010-01-01
Extending previous results of Oh--Zumbrun and Johnson--Zumbrun, we show that spectral stability implies linearized and nonlinear stability of spatially periodic traveling-wave solutions of viscous systems of conservation laws for systems of generic type, removing a restrictive assumption that wave speed be constant to first order along the manifold of nearby periodic solutions.
Dynamical tunneling of a Bose-Einstein condensate in periodically driven systems.
Shrestha, R K; Ni, J; Lam, W K; Summy, G S; Wimberger, S
2013-09-01
We report measurements of dynamical tunneling rates of a Bose-Einstein condensate across a barrier in classical phase space. The atoms are initially prepared in quantum states that extend over a classically regular island region. We focus on the specific system of quantum accelerator modes of the kicked rotor in the presence of gravity. Our experimental data is supported by numerical simulations taking into account imperfections mainly from spontaneous emission. Furthermore, we predict experimentally accessible parameter ranges over which direct tunneling could be readily observed if spontaneous emission was further suppressed. Altogether, we provide a proof-of-principle for the experimental accessibility of dynamical tunneling rates in periodically driven systems. PMID:24125389
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 PoincarÃ© 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 Sunâ€“Jupiter mass parameter, we provide energy ranges for which the transition between different resonances is possible. (paper)
Directory of Open Access Journals (Sweden)
Jan FILIPCZYK
2015-12-01
Full Text Available The increasing number of road accidents nowadays seems to by a global problem. Apart from the obvious causes of accidents, such as violation of road traffic rules by drivers and pedestrians, the drunk driving, poor quality of road infrastructure, the technical faults of vehicles should also be take into account. Reasons of technical failures can be the failure of parts, components and assemblies caused by aging, poor quality or non-observance of technological norms when they are installed. It is possible to prevent the occurrence of faults by applying warning methods, one of which is obligatory periodic technical inspection. The purpose of this article is to analyze the characteristic features of the systems of technical inspections in automotive transport used in Poland and Russia. It makes it possible to identify common features and distinctive features of systems in both countries.
Non-Linear Second-Order Periodic Systems with Non-Smooth Potential
Indian Academy of Sciences (India)
Evgenia H Papageorgiou; Nikolaos S, Papageorgiou
2004-08-01
In this paper we study second order non-linear periodic systems driven by the ordinary vector -Laplacian with a non-smooth, locally Lipschitz potential function. Our approach is variational and it is based on the non-smooth critical point theory. We prove existence and multiplicity results under general growth conditions on the potential function. Then we establish the existence of non-trivial homoclinic (to zero) solutions. Our theorem appears to be the first such result (even for smooth problems) for systems monitored by the -Laplacian. In the last section of the paper we examine the scalar non-linear and semilinear problem. Our approach uses a generalized Landesmanâ€“Lazer type condition which generalizes previous ones used in the literature. Also for the semilinear case the problem is at resonance at any eigenvalue.
Quasi-periodic motions in families of dynamical systems order amidst chaos
Broer, Hendrik W; Sevryuk, Mikhail B
1996-01-01
This book is on Kolmogorov-Arnol'd-Moser theory for quasi-periodic tori in dynamical systems. It gives an up-to-date report on the role parameters play for persis- tence of such tori, typically occuring on Cantor sets of positive Hausdorff measure inside phase and parameter space. The cases with preservation of symplectic or volume forms or time-reversal symmetries are included. The concepts of Whitney-smoothness and Diophantine approximation of Cantor sets on submanifolds of Euclidean space are treated, as well as Bruno's theory on analytic continuation of tori. Partly this material is new to Western mathematicians. The reader should be familiar with dynamical systems theory, differen- tial equations and some analysis. The book is directed to researchers, but its entrance level is introductory.
The ground state of binary systems with a periodic modulation of the linear coupling
Niederberger, Armand; Lewenstein, Maciej
2010-01-01
We consider a quasi-one-dimensional two-component systm, described by a pair of Nonlinear Schr\\"{o}dinger/Gross-Pitaevskii Equations (NLSEs/GPEs), which are coupled by the linear mixing, with local strength $\\Omega $, and by the nonlinear incoherent interaction. We assume the self-repulsive nonlinearity in both components, and include effects of a harmonic trapping potential. The model may be realized in terms of periodically modulated slab waveguides in nonlinear optics, and in Bose-Einstein condensates too. Depending on the strengths of the linear and nonlinear couplings between the components, the ground states (GSs) in such binary systems may be symmetric or asymmetric. In this work, we introduce a periodic spatial modulation of the linear coupling, making $\\Omega $ an odd, or even function of the coordinate. The sign flips of $\\Omega (x)$ strongly modify the structure of the GS in the binary system, as the relative sign of its components tends to lock to the local sign of $\\Omega $. Using a systematic nu...
Statistics of Long-Period Gas Giant Planets in Known Planetary Systems
Levesque Bryan, Marta; Knutson, Heather; Howard, Andrew; Ngo, Henry; Batygin, Konstantin; Crepp, Justin; Fulton, Benjamin; Hinkley, Sasha; Isaacson, Howard T.; Johnson, John Asher; Marcy, Geoffrey W.; Wright, Jason
2015-12-01
We conducted a Doppler survey at Keck combined with NIRC2 K-band AO imaging to search for massive, long-period companions to 123 known exoplanet systems with one or two planets detected using the radial velocity (RV) method. Our survey is sensitive to Jupiter mass planets out to 20 AU for a majority of the stars in our sample, and we report the discovery of eight new long-period planets in addition to 20 RV trends at 3 sigma significance indicating the presence of an outer companion beyond 5 AU. We combined our RV observations with AO imaging to determine the range of allowed masses and orbital separations for these companions and fit this population with a power law in mass and semi-major axis. We estimate the total occurrence rate of companions in our sample, and find that hot and warm gas giants inside 1 AU are more likely to have an outer companion than cold gas giants. We also find that planets with an outer companion have higher than average eccentricities than their single counterparts, suggesting that dynamical interactions between planets may play an important role in these systems.
The physical nature of the short-period RS CVn system DV Psc
Zhang, X. B.; Zhang, R. X.
2007-12-01
We present multicolour CCD photometry of the short-period RS CVn-type binary DV Psc obtained in 2006 September and October. Our observations indicate that GSC0008-789, the comparison star used by Robb et al. in their discovery of DV Psc, is a variable with amplitude exceeding 0.08 mag. Based on the new data, the orbital period of the eclipsing system is revised to 0.30853609 d. From the new observations, a set of completely covered B, V and R light curves and a single V-band light curve are formed in two epochs. The radial-velocity curves obtained by Lu, Rucinski & Ogloza are reformed with the newly determined ephemeris and are analysed along with the light curves using the 2003 version of the Wilson-Devinney code. The results show that DV Psc is a detached, near-contact binary system with a mass ratio of 0.693 +/- 0.005 and a separation of 2.038Rsolar. The masses and radii for the components are determined as 0.70 +/- 0.02Msolar, 0.68 +/- 0.03Rsolar for the primary, and 0.49 +/- 0.01Msolar, 0.51 +/- 0.02Rsolar for the secondary.
Energy Technology Data Exchange (ETDEWEB)
Song, Tae Young [Nuclear Engineering and Technology Institute, Daejeon (Korea, Republic of)
2007-07-01
At present, the 10-year Periodic Safety Review(PSR) has been performing to confirm all the aspects of safety issues for all the operating plants in compliance with domestic nuclear law of article 23, subarticle 3. For each plant, in addition, Probabilistic Safety Assessment(PSA) and Severe Accident Management Guideline(SAMG) are being implemented and revised periodically to reflect the latest safety level according to principle fulfillment of severe accident policy statement. The assessment reports, as one of outcomes from these activities, are submitted into and reviewed by domestic regulatory body. During reviewing (in-office duty) and licensing (regulatory duty) process, a large number of outcomes of which most are the formal technical reports and licensing materials, are inevitably produced. Moreover, repeated review process over the plants can make them accumulated and produce a variety of documents additionally. This circumstance motivates to develop effective tool or system for the management of these reports and related technical documents for the future use in licensing process and for subsequent plant assessments. This paper presents the development status of Safety Assessment Information System(SAIS) which manages safety-related documents of PSR, PSA and SAMG for practical use for experienced engineers in charge of these areas.
Energy Technology Data Exchange (ETDEWEB)
Raupach, Marc; Tonner, Ralf, E-mail: tonner@chemie.uni-marburg.de [Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35032 Marburg (Germany)
2015-05-21
The development and first applications of a new periodic energy decomposition analysis (pEDA) scheme for extended systems based on the Kohn-Sham approach to density functional theory are described. The pEDA decomposes the bonding energy between two fragments (e.g., the adsorption energy of a molecule on a surface) into several well-defined terms: preparation, electrostatic, Pauli repulsion, and orbital relaxation energies. This is complemented by consideration of dispersion interactions via a pairwise scheme. One major extension toward a previous implementation [Philipsen and Baerends, J. Phys. Chem. B 110, 12470 (2006)] lies in the separate discussion of electrostatic and Pauli and the addition of a dispersion term. The pEDA presented here for an implementation based on atomic orbitals can handle restricted and unrestricted fragments for 0D to 3D systems considering periodic boundary conditions with and without the determination of fragment occupations. For the latter case, reciprocal space sampling is enabled. The new method gives comparable results to established schemes for molecular systems and shows good convergence with respect to the basis set (TZ2P), the integration accuracy, and k-space sampling. Four typical bonding scenarios for surface-adsorbate complexes were chosen to highlight the performance of the method representing insulating (CO on MgO(001)), metallic (H{sub 2} on M(001), M = Pd, Cu), and semiconducting (CO and C{sub 2}H{sub 2} on Si(001)) substrates. These examples cover diverse substrates as well as bonding scenarios ranging from weakly interacting to covalent (shared electron and donor acceptor) bonding. The results presented lend confidence that the pEDA will be a powerful tool for the analysis of surface-adsorbate bonding in the future, enabling the transfer of concepts like ionic and covalent bonding, donor-acceptor interaction, steric repulsion, and others to extended systems.
Raupach, Marc; Tonner, Ralf
2015-05-21
The development and first applications of a new periodic energy decomposition analysis (pEDA) scheme for extended systems based on the Kohn-Sham approach to density functional theory are described. The pEDA decomposes the bonding energy between two fragments (e.g., the adsorption energy of a molecule on a surface) into several well-defined terms: preparation, electrostatic, Pauli repulsion, and orbital relaxation energies. This is complemented by consideration of dispersion interactions via a pairwise scheme. One major extension toward a previous implementation [Philipsen and Baerends, J. Phys. Chem. B 110, 12470 (2006)] lies in the separate discussion of electrostatic and Pauli and the addition of a dispersion term. The pEDA presented here for an implementation based on atomic orbitals can handle restricted and unrestricted fragments for 0D to 3D systems considering periodic boundary conditions with and without the determination of fragment occupations. For the latter case, reciprocal space sampling is enabled. The new method gives comparable results to established schemes for molecular systems and shows good convergence with respect to the basis set (TZ2P), the integration accuracy, and k-space sampling. Four typical bonding scenarios for surface-adsorbate complexes were chosen to highlight the performance of the method representing insulating (CO on MgO(001)), metallic (H2 on M(001), M = Pd, Cu), and semiconducting (CO and C2H2 on Si(001)) substrates. These examples cover diverse substrates as well as bonding scenarios ranging from weakly interacting to covalent (shared electron and donor acceptor) bonding. The results presented lend confidence that the pEDA will be a powerful tool for the analysis of surface-adsorbate bonding in the future, enabling the transfer of concepts like ionic and covalent bonding, donor-acceptor interaction, steric repulsion, and others to extended systems. PMID:26001445
Molinaro, R; Marconi, M; Bono, G; Lub, J; Pedicelli, S; Pel, J W
2010-01-01
We present a new derivation of the CORS Baade-Wesselink method in the Walraven photometric system. We solved the complete Baade-Wesselink equation by calibrating the surface brightness function with a recent grid of atmosphere models. The new approach was adopted to estimate the mean radii of a sample of Galactic Cepheids for which are available precise light curves in the Walraven bands. Current radii agree, within the errors, quite well with Cepheid radii based on recent optical and near-infrared interferometric measurements. We also tested the impact of the projection factor on the Period-Radius relation using two different values (p=1.36, p=1.27) that bracket the estimates available in the literature. We found that the agreement of our Period-Radius relation with similar empirical and theoretical Period-Radius relations in the recent literature, improves by changing the projection factor from p=1.36 to p=1.27. Our Period-Radius relation is log(R)=(0.75\\pm 0.03)log(P)+(1.10 \\pm 0.03), with a rms=0.03 dex. ...
Influence of periodic water level increase on flow in Pozna? Water Ways System
Directory of Open Access Journals (Sweden)
Tomasz Ka?u?a
2013-06-01
Full Text Available In the period 1968-1972, a project named “Rebuilding of the Pozna? Water Ways System” was carried out. Within the scope of the project the Chwaliszewo Meander of the Warta river was cut off and covered. A discussion about reconstruction of Chwaliszewo Meander has been run for many years. The results of hydraulic computations of the influence of a weir on water table distribution in Pozna? Water Ways System have been presented in the paper. Two different localizations of the weir were considered. Initial maximum water level of upper side of the weir was calculated. The influence of damming up on water level distribution in the Pozna? Water Ways System was analysed. One-dimensional unsteady open channel flow computer systems HEC-RAS and SPRuNeR were used to carry out calculations. Building the weir, regardless of its localization, allows to raise water level in the main channel of the Warta river, increase minimum water depth and point to the architecture and recreation values of the Warta river. It is assumed that damming up is necessary only for flow rate below 100 m3/s in both localizations of the weir. The weir in focus should not create obstacles to the inland navigation and fish migration. To meet these requirements two additional hydraulic constructions must be projected: sluice and fish migration water gate.
Kunder, Andrea; Walker, Alistair; Stetson, Peter B; Bono, Giuseppe; Nemec, James M.; de Propris, Roberto; Monelli, Matteo; Cassisi, Santi; Andreuzzi, Gloria; Dall'Ora, Massimo; Di Cecco, Alessandra; Zoccali, Manuela
2010-01-01
We present period change rates (dP/dt) for 42 RR Lyrae variables in the globular cluster IC$\\,$4499. Despite clear evidence of these period increases or decreases, the observed period change rates are an order of magnitude larger than predicted from theoretical models of this cluster. We find there is a preference for increasing periods, a phenomenon observed in most RR Lyrae stars in Milky Way globular clusters. The period-change rates as a function of position in the perio...
IP Eri: A surprising long-period binary system hosting a He white dwarf
Merle, T; Masseron, T; Van Eck, S; Siess, L; Van Winckel, H
2014-01-01
We determine the orbital elements for the K0 IV + white dwarf (WD) system IP Eri, which appears to have a surprisingly long period of 1071 d and a significant eccentricity of 0.25. Previous spectroscopic analyses of the WD, based on a distance of 101 pc inferred from its Hipparcos parallax, yielded a mass of only 0.43 M$_\\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...
Scientific Electronic Library Online (English)
W. M., Oliva; E. M., Sallum.
1996-06-01
Full Text Available Desenvolveu-se um modelo matemático para analisar a dinâmica das populações de indivíduos e mosquitos infectados quando as populações de mosquitos são periódicas no tempo. Pela determinação de um parâmetro lambda (o raio espectral de uma matriz de monodromia) pode-se estabelecer que a infecção termi [...] na naturalmente (lambda 1 que a infecção torna-se endêmica. O modelo generaliza, para o caso de coeficientes periódicos, modelos anteriores para malária; como também é uma variação de modelo para a gonorréia. A principal motivação para a consideração do modelo proposto foram os recentes estudos sobre mosquitos numa estação experimental de arroz irrigado, na região Sudeste do Brasil. Abstract in english A mathematical model for the purpose of analysing the dynamic of the populations of infected hosts anf infected mosquitoes when the populations of mosquitoes are periodic in time is here presented. By the computation of a parameter lambda (the spectral radius of a certain monodromy matrix) one can s [...] tate that either the infection peters out naturally) (lambda 1 the infection becomes endemic. The model generalizes previous models for malaria by considering the case of periodic coefficients; it is also a variation of that for gonorrhea. The main motivation for the consideration of this present model was the recent studies on mosquitoes at an experimental rice irrigation system, in the South-Eastern region of Brazil.
Mäkelä, Antti; Enno, Sven-Erik; Haapalainen, Jussi
2014-03-01
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.
Chemical effects of (n,2n) reactions on iodate and periodates systems
International Nuclear Information System (INIS)
The chemical consequences of (n,2n) reactions on cristalline sodium iodate and periodates were investigated measuring the initial yield and the post irradiation thermal annealing yields (900C) of the separated fractions I-, IO3- and IO4-. NaIO3, NaIO3.H2O and NaIO4, Na4H2IO6, Na4I2O9.3H2O containing 127I and 129I, or both, were irradiated with 14 MeV neutrons. Results obtained show different effects for each system and that 126I and 128I isotopes keep the same behaviour in the irradiated compounds containing only ?127I or 129I and in compounds having both 127I and 129I. Neither isotope effect nor qualitative differences on thermal annealing at 900C were observed. The annealed fractions in the three studied periodates were IO-3 and IO-4. These results differ from the ones reported previously for (n,?) reactions on the same compounds
Assessment of financial flow in the health system of Serbia in a period 2003-2006
Directory of Open Access Journals (Sweden)
Gaji?-Stevanovi? Milena
2010-01-01
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.
Optimal Backup Interval for a Database System with Full and Periodic Incremental Backup
Directory of Open Access Journals (Sweden)
Cunhua Qian
2010-04-01
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.
Periodic and chaotic oscillations in a tumor and immune system interaction model with three delays
International Nuclear Information System (INIS)
In this paper, a tumor and immune system interaction model consisted of two differential equations with three time delays is considered in which the delays describe the proliferation of tumor cells, the process of effector cells growth stimulated by tumor cells, and the differentiation of immune effector cells, respectively. Conditions for the asymptotic stability of equilibria and existence of Hopf bifurcations are obtained by analyzing the roots of a second degree exponential polynomial characteristic equation with delay dependent coefficients. It is shown that the positive equilibrium is asymptotically stable if all three delays are less than their corresponding critical values and Hopf bifurcations occur if any one of these delays passes through its critical value. Numerical simulations are carried out to illustrate the rich dynamical behavior of the model with different delay values including the existence of regular and irregular long periodic oscillations
Hailperin, Max
1993-01-01
This thesis provides design and analysis of techniques for global load balancing on ensemble architectures running soft-real-time object-oriented applications with statistically periodic loads. It focuses on estimating the instantaneous average load over all the processing elements. The major contribution is the use of explicit stochastic process models for both the loading and the averaging itself. These models are exploited via statistical time-series analysis and Bayesian inference to provide improved average load estimates, and thus to facilitate global load balancing. This thesis explains the distributed algorithms used and provides some optimality results. It also describes the algorithms' implementation and gives performance results from simulation. These results show that our techniques allow more accurate estimation of the global system load ing, resulting in fewer object migration than local methods. Our method is shown to provide superior performance, relative not only to static load-balancing schemes but also to many adaptive methods.
Discharge formation systems for generating atomic iodine in a pulse-periodic oxygen-iodine laser
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
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.
Spin Waves in a Ferromagnetic Film with a Periodic System of Antidots
Directory of Open Access Journals (Sweden)
V.V.Â Kulish
2015-03-01
Full Text Available In the paper, spin waves in a thin film (composed of a uniaxial ferromagnet with a two-dimensional periodical system of antidots are studied. The film ferromagnet is considered to have the â€œeasy axisâ€ 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.
Scientific Electronic Library Online (English)
G. M., Ramírez Ávila; J. A., C. Gallas.
Full Text Available Se caracterizan diferentes sistemas dinámicos descritos por mapas mediante el cálculo de periodicidades. Este método es alternativo a los diagramas de bifurcación utilizando los exponentes de Lyapunov ya que no sólo permite visualizar las estructuras existentes en el espacio de parámetros, tales com [...] o los "camarones", sino también proporciona el detalle de los regímenes oscilatorios lo cual puede tener importancia desde el punto de vista práctico. Abstract in english We characterize, by means of periodicities, some dynamical systems represented by maps. This is an alternative method to the common bifurcation diagrams computed by using the Lyapunov exponents and allows us to visualize the typical structures onto the parameter space such as the "shrimps" but in ad [...] dition with the detail of the oscillatory regimes which could be important from a practical viewpoint.
Note: Signal conditioning of a hot-film anemometer for a periodic flow rate monitoring system.
Mantovani, Federico; Tagliaferri, Cristian
2011-12-01
A flow monitoring system based on a constant temperature hot-film anemometer is presented. The device has been designed to monitor a dispensing process of extremely low quantities of adhesive material. The monitoring device presented in this paper is useful in industrial applications where exact flow speed tracking is not needed, but reliability and tolerance to parameters variability are essential. During the design of the device, problems related to the physical characteristic of the calorimetric sensor, in particular its thermal capacitance, and to the periodic nature of the monitored flow have been taken into account and suitable solutions have been implemented. The schematic representation of the monitoring device together with the experimental results obtained by monitoring fluids with different physical characteristics are presented. PMID:22225264
The optimal P3M algorithm for computing electrostatic energies in periodic systems
Ballenegger, V; Holm, Ch; Lenz, O
2007-01-01
We optimize Hockney and Eastwood's Particle-Particle Particle-Mesh (P3M) algorithm to achieve maximal accuracy in the electrostatic energies (instead of forces) in 3D periodic charged systems. To this end we construct an optimal influence function that minimizes the RMS errors in the energies. As a by-product we derive a new real-space cut-off correction term, give a transparent derivation of the systematic errors in terms of Madelung energies, and provide an accurate analytical estimate for the RMS error of the energies. This error estimate is a useful indicator of the accuracy of the computed energies, and allows an easy and precise determination of the optimal values of the various parameters in the algorithm (Ewald splitting parameter, mesh size and charge assignment order).
Periodic and chaotic oscillations in a tumor and immune system interaction model with three delays
Energy Technology Data Exchange (ETDEWEB)
Bi, Ping [Department of Mathematics, Shanghai Key Laboratory of PMMP, East China Normal University, 500 Dongchuan Rd., Shanghai 200241 (China); Center for Partial Differential Equations, East China Normal University, 500 Dongchuan Rd., Shanghai 200241 (China); Ruan, Shigui, E-mail: ruan@math.miami.edu [Department of Mathematics, University of Miami, Coral Gables, Florida 33124-4250 (United States); Zhang, Xinan [School of Mathematics and Statistics, Central China Normal University, Wuhan 430079 (China)
2014-06-15
In this paper, a tumor and immune system interaction model consisted of two differential equations with three time delays is considered in which the delays describe the proliferation of tumor cells, the process of effector cells growth stimulated by tumor cells, and the differentiation of immune effector cells, respectively. Conditions for the asymptotic stability of equilibria and existence of Hopf bifurcations are obtained by analyzing the roots of a second degree exponential polynomial characteristic equation with delay dependent coefficients. It is shown that the positive equilibrium is asymptotically stable if all three delays are less than their corresponding critical values and Hopf bifurcations occur if any one of these delays passes through its critical value. Numerical simulations are carried out to illustrate the rich dynamical behavior of the model with different delay values including the existence of regular and irregular long periodic oscillations.
Discharge formation systems for generating atomic iodine in a pulse-periodic oxygen–iodine laser
International Nuclear Information System (INIS)
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. (laser applications and other topics in quantum electronics)
Range-separated double-hybrid density-functional theory applied to periodic systems
Sansone, Giuseppe; Usvyat, Denis; Toulouse, Julien; Sharkas, Kamal; Maschio, Lorenzo
2015-01-01
Quantum chemistry methods exploiting density-functional approximations for short-range electron-electron interactions and second-order M{{\\o}}ller-Plesset (MP2) perturbation theory for long-range electron-electron interactions have been implemented for periodic systems using Gaussian-type basis functions and the local correlation framework. The performance of these range-separated double hybrids has been benchmarked on a significant set of systems including rare-gas, molecular, ionic, and covalent crystals. The use of spin-component-scaled MP2 for the long-range part has been tested as well. The results show that the value of $\\mu$ = 0.5 bohr^{--1} for the range-separation parameter usually used for molecular systems is also a reasonable choice for solids. Overall, these range-separated double hybrids provide a good accuracy for binding energies using basis sets of moderate sizes such as cc-pVDZ and aug-cc-pVDZ.
Quantum effects on Lagrangian points and displaced periodic orbits in the Earth-Moon system
Battista, Emmanuele; Dell'Agnello, Simone; Esposito, Giampiero; Simo, Jules
2015-04-01
Recent work in the literature has shown that the one-loop long distance quantum corrections to the Newtonian potential imply tiny but observable effects in the restricted three-body problem of celestial mechanics; i.e., at the Lagrangian libration points of stable equilibrium, the planetoid is not exactly at an equal distance from the two bodies of large mass, but the Newtonian values of its coordinates are changed by a few millimeters in the Earth-Moon system. First, we assess such a theoretical calculation by exploiting the full theory of the quintic equation, i.e., its reduction to Bring-Jerrard form and the resulting expression of roots in terms of generalized hypergeometric functions. By performing the numerical analysis of the exact formulas for the roots, we confirm and slightly improve the theoretical evaluation of quantum corrected coordinates of Lagrangian libration points of stable equilibrium. Second, we prove in detail that for collinear Lagrangian points the quantum corrections are also of the same order of magnitude in the Earth-Moon system. Third, we discuss the prospects of measuring, with the help of laser ranging, the above departure from the equilateral triangle picture, which is a challenging task. On the other hand, a modern version of the planetoid is the solar sail, and much progress has been made, in recent years, on the displaced periodic orbits of solar sails at all libration points, both stable and unstable. Therefore, the present paper investigates, eventually, a restricted three-body problem involving Earth, the Moon, and a solar sail. By taking into account the one-loop quantum corrections to the Newtonian potential, displaced periodic orbits of the solar sail at libration points are again found to exist.
Periodic responses of a pulley-belt system with one-way clutch under inertia excitation
Ding, Hu
2015-09-01
The stable steady-state periodic response of a two-pulley belt drive system coupled with an accessory by a one-way clutch is presented. For the first time, the pulley-belt system is studied under double excitations. Specifically, the dual excitations consist of harmonic motion of the driving pulley and inertia excitation. The belt spans are modeled as axially moving viscoelastic beams by considering belt bending stiffness. Therefore, integro-partial-differential equations are derived for governing the transverse vibrations of the belt spans. Moreover, the transverse vibrations of the moving belt are coupled with the rotation vibrations of the pulleys by nonlinear dynamic tension. For describing the unidirectional decoupling function of the one-way device, rotation vibrations of the driven pulley and accessory are modeled as coupled piecewise ordinary differential equations. In order to eliminate the influence of the boundary of the belt spans, the non-trivial equilibriums of the pulley-belt system are numerically determined. Furthermore, A nonlinear piecewise discrete-continuous dynamical system is derived by introducing a coordinate transform. Coupled vibrations of the pulley-belt system are investigated via the Galerkin truncation. The natural frequencies of the coupled vibrations are obtained by using the fast Fourier transform. Moreover, frequency-response curves are abstracted from time histories. Therefore, resonance areas of the belt spans, the driven pulley and the accessory are presented. Furthermore, validity of the Galerkin method is examined by comparing with the differential and integral quadrature methods (DQM & IQM). By comparing the results with and without one-way device, significant damping effect of clutch on the dynamic response is discovered. Furthermore, the effects of the intensity of the driving pulley excitation and the inertia excitation are studied. Moreover, numerical results demonstrate that the two excitations interact on the steady-state response, as well as the damping effect of the one-way clutch.
Investigation of periodic systems by means of the generalized Hill method
International Nuclear Information System (INIS)
We propose the new method of investigation of infinite periodic determination which is a generalized Hill method. This method has been used for finding of the characteristic value for the Hill equation. finding the band structure of the one-dimensional periodic and obtaining of the dispersion equation for the electromagnetic wave propagation in the waveguide by plasma arbitrary periodic density modulation by plasma arbitrary periodic density modulation
Directory of Open Access Journals (Sweden)
Pei-Hao Zhao
2004-12-01
Full Text Available We study the existence and global stability of positive periodic solutions of a periodic discrete predator-prey system with delay and Holling type III functional response. By using the continuation theorem of coincidence degree theory and the method of Lyapunov functional, some sufficient conditions are obtained.
Pei-Hao Zhao; Wan-Tong Li; Lin-Lin Wang
2004-01-01
We study the existence and global stability of positive periodic solutions of a periodic discrete predator-prey system with delay and Holling type III functional response. By using the continuation theorem of coincidence degree theory and the method of Lyapunov functional, some sufficient conditions are obtained.
Analysis of the ancient river system in Loulan period in Lop Nur region
Zhu, Jianfeng; Jia, Peng; Nie, Yueping
2010-09-01
The Lop Nur region is located in the east of the Tarim Basin. It has served as the strategic passage and communication hub of the Silk Road since Han Dynasty. During Wei-Jin period, the river system there was well developed and the ancient city of Loulan was bred there. In this study, GIS is used to accomplish automatic extraction of the river course in the Lop Nur region at first using ArcGIS. Then the RCI index is constituted to extract ancient river course from Landsat ETM image with band 3 and band 4. It is concluded that the north river course of Peacock River conformed before the end of the 4th century AD according to the distribution of the entire river course of the Lop Nur region. Later, the Peacock River changed its way to south to Tarim River, and flowed into Lop Nur along the direction paralleling Altun Mountain from west to east. It was the change of the river system that mainly caused the decrease in water supply around ancient city of Loulan before the end of 4th century. The ancient city of Loulan has been gradually ruined in the sand because of the absence of water supply since then.
PHYSICAL PROPERTIES OF THE 0.94-DAY PERIOD TRANSITING PLANETARY SYSTEM WASP-18
International Nuclear Information System (INIS)
We present high-precision photometry of five consecutive transits of WASP-18, an extrasolar planetary system with one of the shortest orbital periods known. Through the use of telescope defocusing we achieve a photometric precision of 0.47-0.83 mmag per observation over complete transit events. The data are analyzed using the JKTEBOP code and three different sets of stellar evolutionary models. We find the mass and radius of the planet to be M b = 10.43 ± 0.30 ± 0.24 M Jup and R b = 1.165 ± 0.055 ± 0.014 R Jup (statistical and systematic errors), respectively. The systematic errors in the orbital separation and the stellar and planetary masses, arising from the use of theoretical predictions, are of a similar size to the statistical errors and set a limit on our understanding of the WASP-18 system. We point out that seven of the nine known massive transiting planets (M b > 3 M Jup) have eccentric orbits, whereas significant orbital eccentricity has been detected for only four of the 46 less-massive planets. This may indicate that there are two different populations of transiting planets, but could also be explained by observational biases. Further radial velocity observations of low-mass planets will make it possible to choose between these two scenarios.
Short-period low-mass binary system CC Com revisited
Kose, O; Keskin, V; Ulas, B; Yakut, K
2011-01-01
In this study we determined precise orbital and physical parameters of the very short period low-mass contact binary system CC Com. The parameters are obtained by analysis of the new CCD data with the archival spectroscopic data. The physical parameters of the components derived as $M_\\textrm{c}$ = 0.717(14) $M_{\\odot}$, $M_\\textrm{h}$ = 0.378(8) $M_{\\odot}$, $R_\\textrm{c}$ = 0.708(12) $R_{\\odot}$, $R_\\textrm{h}$ = 0.530(10) $R_{\\odot}$, $L_\\textrm{c}$ = 0.138(12) $L_{\\odot}$, $L_\\textrm{h}$ = 0.085(7) $L_{\\odot}$, and the distance of the system is estimated as 64(4) pc. The times of minima obtained in this study and with those published before enable us to calculate the mass transfer rate between the components which is $1.6\\times10^{-8}$ M$_{\\odot}$yr$^{-1}$. Finally, we discuss the possible evolutionary scenario of CC Com.
Physical properties of the 0.94-day period transiting planetary system WASP-18
Southworth, John; Dominik, M; Glitrup, M; Jørgensen, U G; Liebig, C; Mathiasen, M; Anderson, D R; Bozza, V; Browne, P; Burgdorf, M; Novati, S Calchi; Dreizler, S; Finet, F; Harpsoe, K; Hessman, F; Hundertmark, M; Maier, G; Mancini, L; Maxted, P F L; Rahvar, S; Ricci, D; Scarpetta, G; Skottfelt, J; Snodgrass, C; Surdej, J; Zimmer, F
2009-01-01
We present high-precision photometry of five consecutive transits of WASP-18, an extrasolar planetary system with one of the shortest orbital periods known. Through the use of telescope defocussing we achieve a photometric precision of 0.47 to 0.83 mmag per observation over complete transit events. The data are analysed using the JKTEBOP code and three different sets of stellar evolutionary models. We find the mass and radius of the planet to be M_b = 10.43 +/- 0.30 +/- 0.24 Mjup R_b = 1.165 +/- 0.055 +/- 0.014 Rjup (statistical and systematic errors) respectively. The systematic errors in the orbital separation and the stellar and planetary masses, arising from the use of theoretical predictions, are of a similar size to the statistical errors and set a limit on our understanding of the WASP-18 system. We point out that seven of the nine known massive transiting planets (M_b > 3 Mjup) have eccentric orbits, whereas significant orbital eccentricity has been detected for only four of the 46 less massive planet...
New dimensions of the periodic system: superheavy, superneutronic, superstrange, antimatter nuclei
Greiner, Walter
2010-12-01
The possibilities for the extension of the periodic system into the islands of superheavy (SH) elements, to and beyond the neutron drip line and to the sectors of strangeness and antimatter are discussed. The multi-nucleon transfer processes in low-energy damped collisions of heavy actinide nuclei may help us to fill the gap between the nuclei produced in the "hot" fusion reactions and the continent of known nuclei. In these reactions we may also investigate the "island of stability". In many such collisions the lifetime of the composite giant system consisting of two touching nuclei turns out to be rather long (?10-20 s); sufficient for observing line structure in spontaneous positron emission from super-strong electric fields (vacuum decay), a fundamental QED process not observed yet experimentally. At the neutron-rich sector near the drip line islands and extended ridges of quasistable nuclei are predicted by HF calculations. Such nuclei, as well as very long living superheavy nuclei may be provided in double atomic bomb explosions. A tremendously rich scenario of new nuclear structure emerges with new magic numbers in the strangeness domain. Various production mechanisms are discussed for these objects and for antinuclei in high energy heavy-ion collisions.
Energy Technology Data Exchange (ETDEWEB)
Steffen, Jason H.; Farr, Will M., E-mail: jason.steffen@northwestern.edu [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States)
2013-09-01
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 {approx}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{identical_to}P{sub 2}/P{sub 1}{approx}>2.3 (P{sub 1}/day){sup -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.
International Nuclear Information System (INIS)
It is well known that the Schroedinger equation is equivalent to the wave equation for conservative bound quantum systems. Consequently, the motion of such a system is represented - from a mathematical point of view - by the motion of the characteristic surface of the wave equation. In this paper we present a demonstration of the periodic motion of the characteristic surface. It results that the normal curves of the characteristic surface are periodic solutions of the Hamilton-Jacobi equation written for the same system. This leads to a direct connection between the periodic solutions of the Hamilton-Jacobi equation and the wave properties of the system. The constants of motion corresponding to the above periodic solutions of the Hamilton-Jacobi equation are identical to the eigenvalues of the Schroedinger equation. These properties are proved without any approximation and they are valid for all the values of the principal quantum number
Towards a Fundamental Understanding of Short Period Eclipsing Binary Systems Using Kepler Data
Prsa, Andrej
Kepler's ultra-high precision photometry is revolutionizing stellar astrophysics. We are seeing intrinsic phenomena on an unprecedented scale, and interpreting them is both a challenge and an exciting privilege. Eclipsing binary stars are of particular significance for stellar astrophysics because precise modeling leads to fundamental parameters of the orbiting components: masses, radii, temperatures and luminosities to better than 1-2%. On top of that, eclipsing binaries are ideal physical laboratories for studying other physical phenomena, such as asteroseismic properties, chromospheric activity, proximity effects, mass transfer in close binaries, etc. Because of the eclipses, the basic geometry is well constrained, but a follow-up spectroscopy is required to get the dynamical masses and the absolute scale of the system. A conjunction of Kepler photometry and ground- based spectroscopy is a treasure trove for eclipsing binary star astrophysics. This proposal focuses on a carefully selected set of 100 short period eclipsing binary stars. The fundamental goal of the project is to study the intrinsic astrophysical effects typical of short period binaries in great detail, utilizing Kepler photometry and follow-up spectroscopy to devise a robust and consistent set of modeling results. The complementing spectroscopy is being secured from 3 approved and fully funded programs: the NOAO 4-m echelle spectroscopy at Kitt Peak (30 nights; PI Prsa), the 10- m Hobby-Eberly Telescope high-resolution spectroscopy (PI Mahadevan), and the 2.5-m Sloan Digital Sky Survey III spectroscopy (PI Mahadevan). The targets are prioritized by the projected scientific yield. Short period detached binaries host low-mass (K- and M- type) components for which the mass-radius relationship is sparsely populated and still poorly understood, as the radii appear up to 20% larger than predicted by the population models. We demonstrate the spectroscopic detection viability in the secondary-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.
Periodic orbits of mechanical systems with homogeneous polynomial terms of degree five
Ortega, Alberto Castro
2016-01-01
In this work the existence of periodic solutions is studied for the Hamiltonian functions (Formula presented.) where the first term consist of a harmonic oscillator and the second term are homogeneous polynomials of degree 5 defined by two real parameters (Formula presented.) . Using the averaging method of second order we provide the sufficient conditions on the parameters to guarantee the existence of periodic solutions for positive energy and we study the stability of these periodic solutions.
Directory of Open Access Journals (Sweden)
Afsin Kundak
2014-01-01
Full Text Available In the neonatal period, upper gastrointestinal system (GIS bleeding may be due to benign disorders which do not require any treatments or may be relevant to serious conditions requiring urgent intervention. There are two major causes of upper GIS bleeding developed in the newborns; vitamin K deficiency-induced hemorrhagic disease of the newborn and maternal blood swallowed during birth. Other causes of this type of bleeding include gastritis, esophagitis, peptic ulcus (PU, coagulopathy, sepsis, vascular malformations, trauma, and esofageal-gastric duplications. Rarely, gastric erosion or perforation due to oro/naso gastric tube might cause severe upper GIS bleeding. Hemodynamic resuscitation, bleeding control, and prevention of the recurrence form the basis of the management. However, a somatostatin analogue (ocreotide may be helpful by reducing the splanchnic blood if bleeding is caused by a known vascular lesion or arterial erosion. In this paper, a case of newborn with upper GIS bleeding developed within the first 24 hour life and probably caused by arterial erosion due to oro/gastric tube and treated by ocreotide was presented in the light of literature.
Multi-Layered Ring Log-Periodic Antennas Array Design for GPS Systems
Directory of Open Access Journals (Sweden)
M. Abri
2012-06-01
Full Text Available The objective of the present study is the design of log periodic ring printed antennas array witch generates circular polarization with wide band by single feed linearly polarized elements for GPS systems. The radiating elements have been fed by magnetic coupling through a slot. The circular polarization is achieved by having a basic 2×2 sub-arrays with unique element angular and phase arrangement, both the element angular orientation and feed phase are arranged in the 0°, 90°, 180 and 270° fashion. The purpose of different angular orientations of the patches is to generate two orthogonally polarized fields, while -3dB coupler is used to provide the required amplitude and phase delays for circular polarization generation. This uniquely formed array has the capability of generating excellent circular polarization. An association of the coupler with the antennas has been established.This work is completed using the moment’s method of Momentum software. Good performances of adaptation and polarization were obtained. The simulation results are then presented and discussed.
A Periodical Production Plan for Uncertain Orders in a Closed-Loop Supply Chain System
Directory of Open Access Journals (Sweden)
Hsiao-Fan Wang
2014-12-01
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
Lu, Nan; Tian, Ying; Tian, Wei; Huang, Peng; Liu, Ying; Tang, Yuxia; Wang, Chunyan; Wang, Shouju; Su, Yunyan; Zhang, Yunlei; Pan, Jing; Teng, Zhaogang; Lu, Guangming
2016-02-10
The integration of diagnosis and therapy into one nanoplatform, known as theranostics, has attracted increasing attention in the biomedical areas. Herein, we first present a cancer cell targeting imaging and drug delivery system based on engineered thioether-bridged periodic mesoporous organosilica nanoparticles (PMOs). The PMOs are stably and selectively conjugated with near-infrared fluorescence (NIRF) dye Cyanine 5.5 (Cy5.5) and anti-Her2 affibody on the outer surfaces to endow them with excellent NIRF imaging and cancer targeting properties. Also, taking the advantage of the thioether-group-incorporated mesopores, the release of chemotherapy drug doxorubicin (DOX) loaded in the PMOs is responsive to the tumor-related molecule glutathione (GSH). The drug release percentage reaches 84.8% in 10 mM of GSH solution within 24 h, which is more than 2-fold higher than that without GSH. In addition, the drug release also exhibits pH-responsive, which reaches 53.6% at pH 5 and 31.7% at pH 7.4 within 24 h. Confocal laser scanning microscopy and flow cytometry analysis demonstrate that the PMOs-based theranostic platforms can efficiently target to and enter Her2 positive tumor cells. Thus, the smart imaging and drug delivery nanoplatforms induce high tumor cell growth inhibition. Meanwhile, the Cy5.5 conjugated PMOs perform great NIRF imaging ability, which could monitor the intracellular distribution, delivery and release of the chemotherapy drug. In addition, cell viability and histological assessments show the engineered PMOs have good biocompatibility, further encouraging the following biomedical applications. Over all, the systemically engineered PMOs can serve as a novel cancer cell targeting imaging and drug delivery platform with NIRF imaging, GSH and pH dual-responsive drug release, and high tumor cell targeting ability. PMID:26767305
Southworth, John; Gaensicke, B T; Copperwheat, C M
2014-01-01
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...
Ates, Muzaffer
2011-01-01
In this paper, we study the existence and uniqueness of periodic solutions of the differential equation of the form . Here, we obtain some sufficient conditions which guarantee the existence of periodic solutions. This equation is a quite general third- order nonlinear vector differential equation, and one example is given for illustration of the subject.
Dena, Ángeles; Abad, Alberto; Barrio, Roberto
2016-01-01
In this paper, we study the problem of computing periodic orbits of Hamiltonian systems providing large families of such orbits. Periodic orbits constitute one of the most important invariants of a system, and this paper provides a comprehensive analysis of two efficient computational approaches for Hamiltonian systems. First, a new version of the grid search method, applied to problems with three degrees of freedom, has been considered to find, systematically, symmetric periodic orbits. To obtain non-symmetric periodic orbits, we use a modification of an optimization method based on an evolutionary strategy. Both methods require a great computational effort to find a big number of periodic orbits, and we apply parallelization tools to reduce the CPU time. Finally, we present a strategy to provide initial conditions of the periodic orbits with arbitrary precision. We apply all these algorithms to the problem of the motion of the lunar orbiter referred to the rotating reference frame of the Moon. The periodic orbits of this problem are very useful from the space engineering point of view because they provide low-cost orbits.
International Nuclear Information System (INIS)
The purpose of this research is to obtain the optimum sampling period for evaluating solar photovoltaic generation beforehand. For this purpose, the solar radiation was measured over 1 year at the once per a week. The effect of the sampling period on the integral error of amount of solar radiation was analyzed, and the fractal analysis of the solar radiation was carried out. As a result, the following issues were clarified. Er = 0,0117t and r = 0.00201Qa + 1.934 were obtained as a relational expressions of the sampling period (t) and the integral error (Er) in amount of solar radiation, and of the amount of solar radiation (Qa) and the sampling period (t). Upper limit in the optimum sampling period was the 236 seconds, when allowed integral error of amount of solar radiation was 3%
International Nuclear Information System (INIS)
The abstracts of the XIX Mendeleev Congress on general and applied chemistry held 25-30 September 2011 in Volgograd are presented. The program includes the Congress plenary and section reports, poster presentations, symposia and round tables on key areas of chemical science and technology, and chemical education. The work of the Congress was held the following sections: 1. Fundamental problems of chemical sciences; 2. Chemistry and technology of materials, including nanomaterials; 3. Physicochemical basis of metallurgical processes; 4. Current issues of chemical production, technical risk assessment; 5. Chemical aspects of modern power and alternative energy sources; 6. Chemistry of fossil and renewable hydrocarbons; 7. Analytical chemistry: new methods and instruments for chemical research and analysis; 8. Chemical education. Volume 3 contains the reports correspondence section participants Chemistry and technology of materials, including nanomaterials, abstracts of oral and poster presentations, messages of correspondence participants at meetings of the sections: Physicochemical basis of metallurgical processes; Topical issues of chemical production, technical risk assessment, reports roundtable Interaction chemistry and business, as well as an author index
International Nuclear Information System (INIS)
Present article is devoted to assessment of the degree of certainty of double phase diagrams of lead systems with elements of the periodic table. The analysis of literature data on double phase diagrams of lead with elements of the periodic table was carried out. It was found that from 91 systems Pb-e (element) was studied and constructed diagrams for 50 systems. It was defined that in most cases the constructed state diagrams have to be confirmed by using more cleaner initial source materials and modern methods of physicochemical analysis and thermodynamic calculations.
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
Weak interactions in Graphane/BN systems under static electric fields—A periodic ab-initio study
Energy Technology Data Exchange (ETDEWEB)
Steinkasserer, Lukas Eugen Marsoner, E-mail: marsoner@zedat.fu-berlin.de [Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195 Berlin (Germany); MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, 6140 Wellington (New Zealand); Gaston, Nicola [MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, 6140 Wellington (New Zealand); Paulus, Beate [Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195 Berlin (Germany)
2015-04-21
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.
Weak interactions in Graphane/BN systems under static electric fields—A periodic ab-initio study
International Nuclear Information System (INIS)
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
International Nuclear Information System (INIS)
A series of 62 critical and critical approach experiments were performed to evaluate a possible novel means of storing large volumes of fissile solution in a critically safe configuration. This study is intended to increase safety and economy through use of such a system in commercial plants which handle fissionable materials in liquid form. The fissile solution's concentration may equal or slightly exceed the minimum-critical-volume concentration; and experiments were performed for high-enriched uranium solution. Results should be generally applicable in a wide variety of plant situations. The method is called the 'Poisoned Tube Tank' because strong neutron absorbers (neutron poisons) are placed inside periodically spaced stainless steel tubes which separate absorber material from solution, keeping the former free of contamination. Eight absorbers are investigated. Both square and triangular pitched lattice patterns are studied. Ancillary topics which closely model typical plant situations are also reported. They include the effect of removing small bundles of absorbers as might occur during inspections in a production plant. Not taking the tank out of service for these inspections would be an economic advantage. Another ancillary topic studies the effect of the presence of a significant volume of unpoisoned solution close to the Poisoned Tube Tank on the critical height. A summary of the experimental findings is that boron compounds were excellent absorbers, as expected. This was true for granular materials such as Gerstley Borate and Borax; but it was also true for the flexible solid composed of boron carbide and rubber, even though only thin sheets were used. Experiments with small bundles of absorbers intentionally removed reveal that quite reasonable tanks could be constructed that would allow a few tubes at a time to be removed from the tank for inspection without removing the tank from production service
Energy Technology Data Exchange (ETDEWEB)
Rothe, R.E.
1996-09-30
A series of 62 critical and critical approach experiments were performed to evaluate a possible novel means of storing large volumes of fissile solution in a critically safe configuration. This study is intended to increase safety and economy through use of such a system in commercial plants which handle fissionable materials in liquid form. The fissile solution`s concentration may equal or slightly exceed the minimum-critical-volume concentration; and experiments were performed for high-enriched uranium solution. Results should be generally applicable in a wide variety of plant situations. The method is called the `Poisoned Tube Tank` because strong neutron absorbers (neutron poisons) are placed inside periodically spaced stainless steel tubes which separate absorber material from solution, keeping the former free of contamination. Eight absorbers are investigated. Both square and triangular pitched lattice patterns are studied. Ancillary topics which closely model typical plant situations are also reported. They include the effect of removing small bundles of absorbers as might occur during inspections in a production plant. Not taking the tank out of service for these inspections would be an economic advantage. Another ancillary topic studies the effect of the presence of a significant volume of unpoisoned solution close to the Poisoned Tube Tank on the critical height. A summary of the experimental findings is that boron compounds were excellent absorbers, as expected. This was true for granular materials such as Gerstley Borate and Borax; but it was also true for the flexible solid composed of boron carbide and rubber, even though only thin sheets were used. Experiments with small bundles of absorbers intentionally removed reveal that quite reasonable tanks could be constructed that would allow a few tubes at a time to be removed from the tank for inspection without removing the tank from production service.
Periodic orbits of mechanical systems with homogeneous polynomial terms of degree five
Castro Ortega, Alberto
2016-01-01
In this work the existence of periodic solutions is studied for the Hamiltonian functions H=1/2 bigl( pX2+pY2+X2+Y2 bigr)+a/5X5+bX3Y2, where the first term consist of a harmonic oscillator and the second term are homogeneous polynomials of degree 5 defined by two real parameters a and b. Using the averaging method of second order we provide the sufficient conditions on the parameters to guarantee the existence of periodic solutions for positive energy and we study the stability of these periodic solutions.
Searches for Periodic Neutrino Emission from Binary Systems with 22 and 40 Strings of IceCube
Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Allen, M. M.; Altmann, D.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; BenZvi, S.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Brown, A. M.; Buitink, S.; Caballero-Mora, K. S.; Carson, M.; Chirkin, D.; Christy, B.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D. F.; Cruz Silva, A. H.; D'Agostino, M. V.; Danninger, M.; Daughhetee, J.; Davis, J. C.; De Clercq, C.; Degner, T.; Demirörs, L.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; DeYoung, T.; Díaz-Vélez, J. C.; Dierckxsens, M.; Dreyer, J.; Dumm, J. P.; Dunkman, M.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Góra, D.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gurtner, M.; Ha, C.; Haj Ismail, A.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Heinen, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, B.; Homeier, A.; Hoshina, K.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Kroll, G.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Laihem, K.; Landsman, H.; Larson, M. J.; Lauer, R.; Lünemann, J.; Madsen, J.; Marotta, A.; Maruyama, R.; Mase, K.; Matis, H. S.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Miarecki, S.; Middell, E.; Milke, N.; Miller, J.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; O'Murchadha, A.; Panknin, S.; Paul, L.; Pérez de los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Porrata, R.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Richman, M.; Rodrigues, J. P.; Rothmaier, F.; Rott, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Schmidt, T.; Schönwald, A.; Schukraft, A.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Strahler, E. A.; Ström, R.; Stüer, M.; Sullivan, G. W.; Swillens, Q.; Taavola, H.; Taboada, I.; Tamburro, A.; Tepe, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Toscano, S.; Tosi, D.; van Eijndhoven, N.; Vandenbroucke, J.; Van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, C.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Zoll, M.; IceCube Collaboration
2012-04-01
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.
Hu, Jian; Li, Gangyan; Song, Ye-Qiong
2008-01-01
With the increase of the complexity of automotive control, it is necessary to develop AEIICS (Automotive Electronic and Information Integrated Control System) for exchanging information between ECUs (Electronic Control Units) based on in-vehicle network technology. We named the parameter (or variable) contained in and transmitted by frame as signal. Period and deadline are basic temporal characteristics for signal and frame. Designers mainly focus on directly designing the period and deadline...
DEFF Research Database (Denmark)
Allen, Matthew S.; Sracic, Michael W.; Chauhan, Shashank; Hansen, Morten Hartvig
2011-01-01
Many important systems, such as wind turbines, helicopters and turbomachinery, must be modeled with linear time-periodic equations of motion to correctly predict resonance phenomena. Time periodic effects in wind turbines might arise due to blade-to-blade manufacturing variations, stratification 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 importan...
DEFF Research Database (Denmark)
Allen, Matthew S.; Sracic, Michael W.; Chauhan, Shashank; Hansen, Morten Hartvig
2011-01-01
Many important systems, such as wind turbines, helicopters and turbomachinery, must be modeled with linear time-periodic equations of motion to correctly predict resonance phenomena. Time periodic effects in wind turbines might arise due to blade-to-blade manufacturing variations, stratification in...... 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...
NON-LINEAR FREE PERIODIC OSCILLATIONS OF A TETHERED SATELLITE SYSTEM
Luongo, Angelo; Vestroni, Fabrizio
1994-01-01
This paper deals with the non-linear dynamics of a tethered satellitesystem, with particular reference to periodic transverse oscillations. The motion is governed by two integro-differential equations with quadratic non-linear terms associated to gyroscopic forces. Notwithstanding the weakness of the non-linearities, the closeness of the in-planeand out-of-plane frequencies suggest that it would be interesting to study the periodic finite oscillations and analyze their stability. Since the sy...
Chow, KW; Li, JH; Lou, SY
2011-01-01
Exact doubly periodic standing wave patterns of the Davey-Stewartson (DS) equations are derived in terms of rational expressions of elliptic functions. In fluid mechanics, DS equations govern the evolution of weakly nonlinear, free surface wave packets when long wavelength modulations in two mutually perpendicular, horizontal directions are incorporated. Elliptic functions with two different moduli (periods) are necessary in the two directions. The relation between the moduli and the wave num...
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)
Tunable wideband bandstop acoustic filter based on 2D multi-physical phenomena periodic systems
Romero-García, V.; Sánchez-Pérez, J. V.; GARCIA-RAFFI, L.M.
2011-01-01
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...
International Nuclear Information System (INIS)
Nuclear standby safety systems must frequently, be submitted to periodic surveillance tests. The main reason is to detect, as soon as possible, the occurrence of unrevealed failure states. Such interventions may, however, affect the overall system availability due to component outages. Besides, as the components are demanded, deterioration by aging may occur, penalizing again the system performance. By these reasons, planning a good surveillance test policy implies in a trade-off between gains and overheads due to the surveillance test interventions. In order maximize the systems average availability during a given period of time, it has recently been developed a non-periodic surveillance test optimization methodology based on genetic algorithms (GA). The fact of allowing non-periodic tests turns the solution space much more flexible and schedules can be better adjusted, providing gains in the overall system average availability, when compared to those obtained by an optimized periodic tests scheme. The optimization problem becomes, however, more complex. Hence, the use of a powerful optimization technique, such as GAs, is required. Some particular features of certain systems can turn it advisable to introduce other specific constraints in the optimization problem. The Emergency Diesel Generation System (EDGS) of a Nuclear Power Plant (N-PP) is a good example for demonstrating the introduction of seasonal constraints in the optimization problem. This system is responsible for power supply during an external blackout. Therefore, it is desirable during periods of high blackout probability to maintain the system availability as high as possible. Previous applications have demonstrated the robustness and effectiveness of the methodology. However, no seasonal constraints have ever been imposed. This work aims at investigating the application of such methodology in the Angra-II Brazilian NPP EDGS surveillance test policy optimization, considering the blackout probability growth during summer, due to the electrical power demand increase. Here, the model used penalizes test interventions by a continuous modulating function, which depends on the instantaneous blackout probability. Results have demonstrated the ability of the method in adapting the surveillance tests policy to seasonal behaviors. The knowledge acquired by the GA during the searching process has lead to test schedules that drastically minimize the test interventions at periods of high blackout probability. It is compensated by more frequent tests redistributed through the periods of low blackout probability, in order to provide improvement on the overall average availability at the system level. (authors)
Hine, N D M; Haynes, P D; Skylaris, C K
2011-01-01
We present a comparison of methods for treating the electrostatic interactions of finite, isolated systems within periodic boundary conditions (PBCs), within Density Functional Theory (DFT), with particular emphasis on linear-scaling (LS) DFT. Often, PBCs are not physically realistic but are an unavoidable consequence of the choice of basis set and the efficacy of using Fourier transforms to compute the Hartree potential. In such cases the effects of PBCs on the calculations need to be avoided, so that the results obtained represent the open rather than the periodic boundary. The very large systems encountered in LS-DFT make the demands of the supercell approximation for isolated systems more difficult to manage, and we show cases where the open boundary (infinite cell) result cannot be obtained from extrapolation of calculations from periodic cells of increasing size. We discuss, implement and test three very different approaches for overcoming or circumventing the effects of PBCs: truncation of the Coulomb ...
Rokonuzzaman, Mohd; Gosine, Raymond G.
1997-09-01
An intelligent system (IS) senses, reasons and acts to perform its required tasks. Sensors are used to sense environmental parameters, and through the computational intelligence the system understands the situation and takes appropriate steps toward the desired performance. To deploy systems for mission- critical applications, the underlying technology should have the ability to detect the failure of the components as well as to replace faulty components with fault-free ones within a specified time window known as fault-clearance period. The presence of fault-clearance period in the perception phase of system operation results in the loss of on-line data from different sensors and the subsequent loss of valuable information about the environmental parameters. After fault- clearance, a repetition of the sensing cycle will not recover the lost data in sensing highly transient non-periodic signals. Moreover, the unpredictable repetition will create significant overhead to satisfy the stringent timing requirements of the system. A new scheme has been developed to minimize the loss of these real-time sensor's data during fault-clearance period. This scheme is based on the restoration of data through parallel sensing. The restoration processes for both dual and triple modular redundancy schemes have been developed. The effects of both hardware and software implementation of voting logic on the performance of the system and the quality of restoration have been shown. It has been shown that this scheme is capable to recover most of the lost data during fault-clearance.
Balakin, A B; Kisunko, G V
1996-01-01
We discuss a gravitationally induced nonlinearity in hierarchic systems. We consider the generation of extremely low-frequency radio waves with a frequency of the periodic gravitational radiation; the generation is due to an induced nonlinear self-action of electromagnetic radiation in the vicinity of the gravitational-radiation source. These radio waves are a fundamentally new type of response of an electrodynamic system to gravitational radiation. That is why we here use an unconventional term: radio-wave messengers of periodic gravitational radiation.
Ottino, Julio M.
1991-01-01
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.
Directory of Open Access Journals (Sweden)
MoghimiHadji, EHSAN
2013-01-01
Full Text Available Reliability engineers generally have to deal with systems that consist of some components in series and others in parallel. Reliability of a series system can be calculated by multiplying the reliability of individual elements in that system. Failure rate of many deteriorating systems shows a bathtub shape curve. The aim of this paper is to find the average total cost of a series system, from a manufacturer’s point of view, during the first two phases of its life; considering optimality issues for burn-in and warranty periods. Numerical illustration is provided to show the applicability of the model.
Survival probability and saturation energy in periodically driven quantum chaotic systems
Energy Technology Data Exchange (ETDEWEB)
Machida, Manabu, E-mail: mmachida@umich.edu [Department of Mathematics, University of Michigan, Ann Arbor, MI 48109 (United States); Miyashita, Seiji, E-mail: miya@spin.phys.s.u-tokyo.ac.jp [Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
2012-04-30
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.
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.
Tunable wideband bandstop acoustic filter based on 2D multi-physical phenomena periodic systems
Romero-García, V; Garcia-Raffi, L M
2011-01-01
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.
Photometric study of the short period W UMa system VW Cephei
Essam, A; Haroon, A A
2014-01-01
A total of 431 photoelectric B and V observations are presented for the short period . The measurements have been obtained in two successive nights, 27/28 and 28/29 of September 1995, and represent the whole light curve phases. Four times of minimum light, for each filter, were deduced and new periods have been derived as 0.277892 day from the present photometric observations. New light curves have been constructed, investigated and analyzed by using the recent version of W-D code.
Computer program offers new method for constructing periodic orbits in nonlinear dynamical systems
Bennett, A. G.; Hanafy, L. M.; Palmore, J. I.
1968-01-01
Computer program uses an iterative method to construct precisely periodic orbits which dynamically approximate solutions that converge to precise dynamical solutions in the limit of the sequence. The method used is a modification of the generalized Newton-Raphson algorithm used in analyzing two point boundary problems.
DEFF Research Database (Denmark)
Johansen, SÃ¸ren Glud; Thorstenson, Anders
2008-01-01
We extend well-known formulae for the optimal base stock of the inventory system with continuous review and constant lead time to the case with periodic review and stochastic, sequential lead times. Our extension uses the notion of the â€˜extended lead timeâ€™. The derived performance measures are...
DEFF Research Database (Denmark)
Johansen, SÃ¸ren Glud; Thorstenson, Anders
We show that well-known textbook formulae for determining the optimal base stock of the inventory system with continuous review and constant lead time can easily be extended to the case with periodic review and stochastic, sequential lead times. The provided performance measures and conditions for...... optimality are exact....
DEFF Research Database (Denmark)
Johansen, SÃ¸ren Glud; Thorstenson, Anders
2008-01-01
We extend well-known formulae for the optimal base stock of the inventory system with continuous review and constant lead time to the case with periodic review and stochastic, sequential lead times. Our extension uses the notion of the 'extended lead time'. The derived performance measures are...
DEFF Research Database (Denmark)
Johansen, Søren Glud; Thorstenson, Anders
2008-01-01
We extend well-known formulae for the optimal base stock of the inventory system with continuous review and constant lead time to the case with periodic review and stochastic, sequential lead times. Our extension uses the notion of the 'extended lead time'. The derived performance measures are exact for Poisson demands.
DEFF Research Database (Denmark)
Allen, Matthew S.; Sracic, Michael W.
2011-01-01
Many important systems, such as wind turbines, helicopters and turbomachinery, must be modeled with linear time-periodic equations of motion to correctly predict resonance phenomena. Time periodic effects in wind turbines might arise due to blade-to-blade manufacturing variations, stratification 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.
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
Allen, Matthew S.; Sracic, Michael W.; Chauhan, Shashank; Hansen, Morten Hartvig
2011-05-01
Many important systems, such as wind turbines, helicopters and turbomachinery, must be modeled with linear time-periodic equations of motion to correctly predict resonance phenomena. Time periodic effects in wind turbines might arise due to blade-to-blade manufacturing variations, stratification 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.
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.
DEFF Research Database (Denmark)
Olsen, Bjarke Tobias; Smith Korsholm, Ulrik; Petersen, Claus; Nielsen, Niels Woetmann; Hansen Sass, Bent; Vedel, Henrik
2015-01-01
At the Danish Meteorological Institute, the NWP nowcasting system has been enhanced to include assimilation of 2D precipitation rates derived from weather radar observations. The assimilation is performed using a nudging-based technique. Here the rain rates are used to estimate the changes in the vertical profile of horizontal divergence needed to induce the observed rain rate. Verification of precipitation forecasts for a 17-day period in August 2010 based on the NWP nowcasting system is presen...
Stability of the Kapchinskij-Vladimirskij (K-V) distribution in long periodic transport systems
International Nuclear Information System (INIS)
Transport of intense beams of heavy ions over long distances may be restricted by space-charge induced transverse instabilities. The stability of the microcanonical, or K-V, distribution is analyzed with the help of the Vlasov equation, and reduced to a study of the characteristics of solutions for a set of ordinary differential equations with periodic coefficients. Numerical solutions for various periodic solenoid and quadrupole focusing channels are derived and provide information concerning stable regions of propagation in terms of betatron tune depression. The results are compared with computer simulation examples of beams in solenoid and quadrupole focusing channels to check linear growth rates and establish nonlinear saturation levels of instabilities. Conclusions are drawn for the design of a quadrupole lattice providing stable transport. (author)
Short period dispersion management of 160 Gb/s single channel fiber system
DEFF Research Database (Denmark)
Zhenbo, Xu; Peucheret, Christophe; Le, Nghi Trong Quang; Jeppesen, Palle
2002-01-01
A transmission distance of 7500 km is numerically predicted for 160 Gb/s single channel fiber systems by using realistic dispersion parameters of ± 6 ps/nm/km. System tolerance on third order dispersion and optical filtering is investigated.
Quasi-periodic solutions of the integrable dynamical systems related to Hill's equation
Kostov, N. A.
1989-02-01
We present finite-gap solutions to the Garnier system and to the g-dimensional anisotropic harmonic oscillator in a radial quartic potential. The relationship between these solutions and solutions of Neumann-type dynamical systems is discussed.
Crossover from dissipative to conservative behaviour in period-doubling systems
Van Der Weele, J. P.; Capel, H. W.; Post, T.; Calkoen, Ch. J.
1986-07-01
We investigate the crossover properties, between the conservative and dissipative limit, for period-doubling bifurcations in two-dimentional iterative maps; as a generic example we use the standard form of the Hénon map. The approximants to the Feigenbaum constant ? lie on a universal crossover curve, which turns out to be non-monotonic. A similar curve is found for the scaling factor ?. More generally, we discuss the crossover of the trajectory scaling function 1/ ?, and its properties in the conservative limit.
Chaos in driven Alfvén systems: unstable periodic orbits and chaotic saddles
A. C.-L. Chian; W. M. Santana; Rempel, E. L.; Borotto, F. A.; T. Hada; Kamide, Y.
2007-01-01
The chaotic dynamics of Alfvén waves in space plasmas governed by the derivative nonlinear Schrödinger equation, in the low-dimensional limit described by stationary spatial solutions, is studied. A bifurcation diagram is constructed, by varying the driver amplitude, to identify a number of nonlinear dynamical processes including saddle-node bifurcation, boundary crisis, and interior crisis. The roles played by unstable periodic orbits and chaotic saddles in these transitions are analyzed, an...
Santhi Baskaran; P. Thambidurai
2010-01-01
Energy consumption is a critical design issue in real-time systems, especially in battery- operated systems. Maintaining high performance, while extending the battery life between charges is an interesting challenge for system designers. Dynamic Voltage Scaling (DVS) allows a processor to dynamically change speed and voltage at run time, thereby saving energy by spreading run cycles into idle time.Knowing when to use full power and when not, requires the cooperation of the operating system ...
Stabilizing periodic orbits of chaotic systems using fuzzy control of Poincare map
Energy Technology Data Exchange (ETDEWEB)
Bonakdar, Mohammad; Samadi, Mostafa [Center of Excellence in Design, Robotics and Automation (CEDRA), Department of Mechanical Engineering, Sharif University of Technology, Azadi Avenue, 1458889694 Tehran (Iran, Islamic Republic of); Salarieh, Hassan [Center of Excellence in Design, Robotics and Automation (CEDRA), Department of Mechanical Engineering, Sharif University of Technology, Azadi Avenue, 1458889694 Tehran (Iran, Islamic Republic of)], E-mail: salarieh@mech.sharif.edu; Alasty, Aria [Center of Excellence in Design, Robotics and Automation (CEDRA), Department of Mechanical Engineering, Sharif University of Technology, Azadi Avenue, 1458889694 Tehran (Iran, Islamic Republic of)
2008-05-15
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.
Chaos in driven Alfvén systems: unstable periodic orbits and chaotic saddles
Directory of Open Access Journals (Sweden)
A. C.-L. Chian
2007-01-01
Full Text Available The chaotic dynamics of Alfvén waves in space plasmas governed by the derivative nonlinear Schrödinger equation, in the low-dimensional limit described by stationary spatial solutions, is studied. A bifurcation diagram is constructed, by varying the driver amplitude, to identify a number of nonlinear dynamical processes including saddle-node bifurcation, boundary crisis, and interior crisis. The roles played by unstable periodic orbits and chaotic saddles in these transitions are analyzed, and the conversion from a chaotic saddle to a chaotic attractor in these dynamical processes is demonstrated. In particular, the phenomenon of gap-filling in the chaotic transition from weak chaos to strong chaos via an interior crisis is investigated. A coupling unstable periodic orbit created by an explosion, within the gaps of the chaotic saddles embedded in a chaotic attractor following an interior crisis, is found numerically. The gap-filling unstable periodic orbits are responsible for coupling the banded chaotic saddle (BCS to the surrounding chaotic saddle (SCS, leading to crisis-induced intermittency. The physical relevance of chaos for Alfvén intermittent turbulence observed in the solar wind is discussed.
Zhao, Yan; Cao, Yanping; Hong, Wei; Wadee, M. Khurram; Feng, Xi-Qiao
2015-01-01
Compression of a stiff film on a soft substrate may lead to surface wrinkling when the compressive strain reaches a critical value. Further compression may cause a wrinkling–folding transition, and the sinusoidal wrinkling mode can then give way to a period-doubling bifurcation. The onset of the primary bifurcation has been well understood, but a quantitative understanding of the secondary bifurcation remains elusive. Our theoretical analysis of the branching of surface patterns reveals that the wrinkling–folding transition depends on the wrinkling strain and the prestrain in the substrate. A characteristic strain in the substrate is adopted to determine the correlation among the critical strain of the period-doubling mode, the wrinkling strain and the prestrain in an explicit form. A careful examination of the total potential energy of the system reveals that beyond the critical strain of period-doubling, the sinusoidal wrinkling mode has a higher potential energy in comparison with the period-doubling mode. The critical strain of the period-doubling mode strongly depends on the deformation state of the hyperelastic solid, indicating that the nonlinear deformation behaviour of the substrate plays a key role here. The results reported here on the one hand provide a quantitative understanding of the wrinkling–folding transition observed in natural and synthetic material systems and on the other hand pave the way to control the wrinkling mode transition by regulating the strain state in the substrate. PMID:25568620
Directory of Open Access Journals (Sweden)
Soyalp Tamçelik
2014-12-01
Full Text Available In this research, regulations concerning the ‘temporary period’ in the new system sought to be established in Cyprus and its properties have been addressed. From this point of view, as the main purpose of this research, the regulations required during the talks taking place between the parties in Cyprus before a federal state is established and how the institutions expected to fulfill these will be structured have been observed. As could be understood from its name, temporary period reflects a certain period and is the period assumed to continue in Cyprus until the formation envisioned to be established there is achieved. Therefore, it is also possible to call this period a ‘transition period’. Actually, the most consistent for-mula that could be brought forward towards this period seems to be the formula of ‘temporary joint administration based on the principle of equality’. This formula, which is important for providing the necessary element of trust for negotiation particularly on issues of territory and constitution and also for displaying whether or not the functional properties of the federal state to be established is based upon a true foundation, appears for now as the most realistic method. On the other hand, the regulations to be made during the temporary period will come into effect with the preparation of the Federal Constitution and the Electoral Law, installing federal bureaucracy, analyzing property claims, determining economic development and protective provisions, regulations regarding territorial adjustments and through Committees, formed by the two communities, in charge of preparing the activity programme. Before a Federal Republic is established, a new state of partnership will emerge after the ‘Temporary Regulations’ enter into force. This partnership will reveal itself as a new state system organized within a framework of a federation that consists of two communities from a constitutional aspect and of two regions from a territorial aspect. Based on this fact, this research consists of two main sections. In the first section, regulations regarding the Temporary Period and other works to be conducted based on the Ghali Set of Ideas have been addressed. In the second and final section, regulations concerning the Temporary Period have been observed based on the Annan Plan.
Scientific Electronic Library Online (English)
Cláudia Simone Madruga, Lima; Michel Aldrighi, Gonçalves; Zeni Fonseca Pinto, Tomaz; Andrea De Rossi, Rufato; José Carlos, Fachinello.
2010-12-01
Full Text Available A physalis (Physalis peruviana) é uma pequena fruta com grandes potencialidades, que, associadas ao seu ciclo curto e às propriedades nutracêuticas, apresenta possibilidade de alto retorno econômico. O objetivo deste trabalho foi avaliar o sistema de tutoramento e a época de transplante mais adequad [...] os para o crescimento e a produção de frutos de P. peruviana nas condições edafoclimáticas do sul do Rio Grande do Sul. O trabalho foi desenvolvido em Pelotas, RS, na safra de 2007/2008. O transplante de mudas de physalis foi realizado em duas épocas (época 1, 21/11/2007 e época 2 15/01/2008), sendo as plantas tutoradas em quatro sistemas de condução (sistema "V" invertido, sistema triangular, sistema vertical com bambu e sistema vertical com fitilho), semelhantes aos utilizados na cultura do tomateiro. O delineamento experimental adotado foi de blocos casualizados, com três repetições, sendo cada um representado por dez plantas. Os tratamentos formaram um fatorial 2x4 (épocas de transplante x sistemas de tutoramento). As variáveis analisadas foram: incremento do comprimento e da área da seção do ramo principal, área da seção do ramo principal, produtividade e eficiência produtiva. Foi evidenciado que a primeira época de transplante associada aos sistemas de tutoramento "V" invertido e triangular proporciona melhor desempenho agronômico das plantas de physalis. Abstract in english The cape-gooseberry (Physalis peruviana) is a small fruit with great potentialities that whether associated to its short cycle and nutraceutical properties it shows high economical return. The work aimed to evaluate the best training system and replant period to plant growth, production and fruit qu [...] ality of P. peruviana under edaphoclimatic at conditions of southern Rio Grande do Sul. The trial was carried out in Pelotas, RS, in 2007/2008 crop. Transplanting seedlings cape-gooseberry was conducted in two seasons Plant replanting was done in two periods (period 1, 21/11/2007 and period 2, 15/01/2008). Plants were trained under four systems (inverted "V" system, triangular system, vertical system using bamboo or vertical system using polypropylene cord), similarly to the tomato culture. Experimental design adopted was a complete randomized block in a 2x4 factorial (replant period x training system) with three replications of ten plants each. The variables analyzed were: increment of length and section area of the main branch, section area of the main branch, yield and yield efficiency. It was evidenced that the first period of replant associated to the training systems inverted "V" and triangular improved the agronomical performance of cape-gooseberry plants.
Directory of Open Access Journals (Sweden)
Cláudia Simone Madruga Lima
2010-12-01
Full Text Available A physalis (Physalis peruviana é uma pequena fruta com grandes potencialidades, que, associadas ao seu ciclo curto e às propriedades nutracêuticas, apresenta possibilidade de alto retorno econômico. O objetivo deste trabalho foi avaliar o sistema de tutoramento e a época de transplante mais adequados para o crescimento e a produção de frutos de P. peruviana nas condições edafoclimáticas do sul do Rio Grande do Sul. O trabalho foi desenvolvido em Pelotas, RS, na safra de 2007/2008. O transplante de mudas de physalis foi realizado em duas épocas (época 1, 21/11/2007 e época 2 15/01/2008, sendo as plantas tutoradas em quatro sistemas de condução (sistema "V" invertido, sistema triangular, sistema vertical com bambu e sistema vertical com fitilho, semelhantes aos utilizados na cultura do tomateiro. O delineamento experimental adotado foi de blocos casualizados, com três repetições, sendo cada um representado por dez plantas. Os tratamentos formaram um fatorial 2x4 (épocas de transplante x sistemas de tutoramento. As variáveis analisadas foram: incremento do comprimento e da área da seção do ramo principal, área da seção do ramo principal, produtividade e eficiência produtiva. Foi evidenciado que a primeira época de transplante associada aos sistemas de tutoramento "V" invertido e triangular proporciona melhor desempenho agronômico das plantas de physalis.The cape-gooseberry (Physalis peruviana is a small fruit with great potentialities that whether associated to its short cycle and nutraceutical properties it shows high economical return. The work aimed to evaluate the best training system and replant period to plant growth, production and fruit quality of P. peruviana under edaphoclimatic at conditions of southern Rio Grande do Sul. The trial was carried out in Pelotas, RS, in 2007/2008 crop. Transplanting seedlings cape-gooseberry was conducted in two seasons Plant replanting was done in two periods (period 1, 21/11/2007 and period 2, 15/01/2008. Plants were trained under four systems (inverted "V" system, triangular system, vertical system using bamboo or vertical system using polypropylene cord, similarly to the tomato culture. Experimental design adopted was a complete randomized block in a 2x4 factorial (replant period x training system with three replications of ten plants each. The variables analyzed were: increment of length and section area of the main branch, section area of the main branch, yield and yield efficiency. It was evidenced that the first period of replant associated to the training systems inverted "V" and triangular improved the agronomical performance of cape-gooseberry plants.
Kukushkin, I V; Smet, J H; Mikhailov, S A; Von Klitzing, K; Aleiner, I L; Fal'ko, V I
2003-01-01
We observe a new type of magneto-oscillations in the photovoltage and the longitudinal resistance of a two-dimensional electron system. The oscillations are induced by microwave irradiation and are periodic in magnetic field. The period is determined by the microwave frequency, the electron density, and the distance between potential probes. The phenomenon is accounted for by coherent excitation of edge magnetoplasmons in the regions near the contacts and offers perspectives for the development of new tunable microwave and terahertz detection schemes and spectroscopic techniques.
A Phase-Locked Loop Model of the Response of the Postural Control System to Periodic Platform Motion
Schilling, Robert J.; Robinson, Charles J.
2010-01-01
A phase-locked loop (PLL) model of the response of the postural control system to periodic platform motion is proposed. The PLL model is based on the hypothesis that quiet standing (QS) postural sway can be characterized as a weak sinusoidal oscillation corrupted with noise. Because the signal to noise ratio is quite low, the characteristics of the QS oscillator are not measured directly from the QS sway, instead they are inferred from the response of the oscillator to periodic motion of the ...
Quasi-Periodic Post-Critical Response Types of a Harmonically Excited Auto-Parametric System.
Czech Academy of Sciences Publication Activity Database
Náprstek, Ji?í; Fischer, Cyril
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
A. P. Shete; A.K.Verma; R. S. Tandel; Chandra Prakash; Tiwari, V. K.; Tanveer Hussain
2013-01-01
Experiment with varied water circulation periods having 4, 8, 12, and 24 hrs/day as T1, T2, T3 and T4, respectively in aquaponics, evaluated against a control (without aquaponics) revealed higher fish and plant growth in T3 and T4. The mean growth of fish varied significantly among treatments showing higher growth in T4 and control followed by T3, T2 and T1. Survival rate was 100% in all the treatments as well as control. Percentage weight gain, SGR (% day-1) also showed the similar trend as ...
Johnson, Mathew A.; Zumbrun, Kevin
Extending previous results of Oh-Zumbrun and Johnson-Zumbrun, we show that spectral stability implies linearized and nonlinear stability of spatially periodic traveling wave solutions of viscous systems of conservation laws for systems of generic type, removing a restrictive assumption that wave speed be constant to first order along the manifold of nearby periodic solutions. Key to our analysis is a nonlinear cancellation estimate observed by Johnson and Zumbrun, along with a detailed understanding of the Whitham averaged system. The latter motivates a careful analysis of the Bloch perturbation expansion near zero frequency and suggests factoring out an appropriate translational modulation of the underlying wave, allowing us to derive the sharpened low-frequency estimates needed to close the nonlinear iteration arguments.
Kamiyama, Kyohei; Inaba, Naohiko; Sekikawa, Munehisa; Endo, Tetsuro
2014-12-01
This report presents an extensive investigation of bifurcations of quasi-periodic oscillations based on an analysis of a coupled delayed logistic map. This map generates an invariant two-torus (IT>2) that corresponds to a three-torus in vector fields. We illustrate detailed Lyapunov diagrams and, by observing attractors, derive a quasi-periodic saddle-node (QSN) bifurcation boundary with a precision of 10-9. We derive a stable invariant one-torus (IT>1) and a saddle IT>1, which correspond to a stable two-torus and a saddle two-torus in vector fields, respectively. We confirmed that the QSN bifurcation boundary coincides with a saddle-node bifurcation point of a stable IT>1 and a saddle IT>1. Our major concern in this study is whether the qualitative transition from an IT>1 to an IT>2 via QSN bifurcations includes phase-locking. We prove with a precision of 10-9 that there is no resonance at the bifurcation point.
Directory of Open Access Journals (Sweden)
Gennadii Demidenko
2002-12-01
Full Text Available This paper is devoted to the study of a nonlinear system of differential equations with two parameters. We determine values of the parameters under which solutions to the system are asymptotically stable. We obtain also estimates enabling us to indicate the decay rate of solutions at infinity.
Farcot, Etienne
2009-01-01
Hybrid systems, and especially piecewise affine (PWA) systems, are often used to model gene regulatory networks. In this paper we elaborate on previous work about control problems for this class of models, using also some recent results guaranteeing the existence and uniqueness of limit cycles, based solely on a discrete abstraction of the system and its interaction structure. Our aim is to control the transition graph of the PWA system to obtain an oscillatory behaviour, which is indeed of primary functional importance in numerous biological networks; we show how it is possible to control the appearance or disappearance of a unique stable limit cycle by hybrid qualitative action on the degradation rates of the PWA system, both by static and dynamic feedback, i.e. the adequate coupling of a controlling subnetwork. This is illustrated on two classical gene network modules, having the structure of mixed feedback loops.
Directory of Open Access Journals (Sweden)
Constanta ENEA
2014-02-01
Full Text Available Since the formation of the United Principalities (24/01/1859, Romania has undergone a series of profound, permanent reforms of its fundamental institutions. The international context had an influence important, often enteritis in shaping its institutions, including the system of taxes. We plan to make a brief review of taxation in modern Romania, starting from the formation of the United Principalities (1859 via the international recognition of Romania as a kingdom (1881, the formation of the National Unitary (1918 international recognition (1919 - 1921, the interwar period (1918-1939, the Second world War (1939-1945 suffered territorial losses in 1940 , the communist period (1945-1989, the post-communist period (1989-2006, will deepen in a future article pre and post EU accession in terms of fiscal and customs.
Progress report of the CEC project Rodos system development. Period: 1 september 92-31 august 93
International Nuclear Information System (INIS)
Within the context of the Radioprotection program of the CEC, the RODOS project (Real-time On-line DecisiOn Support system) aims at the development of a decision support system for nuclear emergencies. RODOS involves 22 research teams, divided in 4 sub-projects: 'Meteorology and Atmospheric Dispersion, 'System Development', 'Decision Aiding Techniques'. The fourth sub-project is a Joint Study Project of the Agreement between CEC ad the CIS republics. EDF is working in the 'System Development' sub-project and namely in the 'training' group. This group aims at the creation of a specific training course for health physics managers, based on RODOS. This note reproduces the progress report of the 'Development System' project. The reporting period is: September 92 - August 93. Progress bas been made within the reporting period in the: - development of data assimilation methods incorporating both monitoring data and model predictions for obtaining consistent pictures of the environmental contamination and the source term ; - improvement and extension of the modules ATSTEP-CORA (atmospheric dispersion and deposition), EMERSIM (simulation of emergency actions), ECOAMOR (exposure pathways and dose calculation) and FRODO (simulation of relocation and agricultural countermeasures) ; - preparation of training courses using RODOS as illustrative tool ; - extension of the functions of the RODOS operating system OSY, in particular of RoGIS, its geographical information system. (author). 2 figs
Pork meat matured for different periods of time in vacuum-packaging system
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Marina Avena Tarsitano
2014-02-01
Full Text Available The objective of this study was to evaluate the quality of pork meat when matured. The treatments evaluated were: meat no maturated; meat matured for 3 days; meat matured for 6 days. The pH, water loss percentage, and liquid lost in thawing displayed a decreasing linear regression while the fluid lost in cooking showed an increasing linear regression. The L*, a*, b* and chroma showed an increasing linear effect while the tone displayed a decreasing linear regression. The mesophilic and psychrotrophic bacteria counts were greater for the treatments that underwent maturation. The shear force decrease linearly with the increase in the maturation period. The MFI, lipid oxidation, and sensory analyses were not affected by treatments. The maturation of the pork meat improved the color, reduced the pH and increased the tenderness. There was no change in the lipid stability of the meat, nor sensory damage.
ARPES in strongly correlated 4f and 5f systems: Comparison to the Periodic Anderson Model
International Nuclear Information System (INIS)
The electronic structure of both Ce and U heavy fermions appears to consist of extremely narrow, nearly temperature independent bands (i.e., no spectral weight loss or transfer with temperature). A small dispersion of the f-bands above the Kondo temperature is easily measurable so that a Kondo resonance, as defined by NCA, is not evident. Preliminary results, however, indicate that the Periodic Anderson Model captures some of the essential physics. Angle-integrated resonant photoemission results on ?-Pu indicate a narrow 5f feature at EF, similar in width to f-states in Ce and U compounds, but differing in that cross-section behavior of the near-EF feature suggests substantial 6D admixture
From plane waves to local Gaussians for the simulation of correlated periodic systems
Booth, George H; Chan, Garnet Kin-Lic; GrÃ¼neis, Andreas
2016-01-01
We present a simple, robust and black-box approach to the implementation and use of local, periodic, atom-centered Gaussian basis functions within a plane wave code, in a computationally efficient manner. The procedure outlined is based on the representation of the Gaussians within a finite bandwidth by their underlying plane wave coefficients. The core region is handled within the projected augment wave framework, by pseudizing the Gaussian functions within a cut-off radius around each nucleus, smoothing the functions so that they are faithfully represented by a plane wave basis with only moderate kinetic energy cutoff. To mitigate the effects of the basis set superposition error and incompleteness at the mean-field level introduced by the Gaussian basis, we also propose a hybrid approach, whereby the complete occupied space is first converged within a large plane wave basis, and the Gaussian basis used to construct a complementary virtual space for the application of correlated methods. We demonstrate that ...
African humid periods triggered the reactivation of a large river system in Western Sahara
Skonieczny, C.; Paillou, P.; Bory, A.; Bayon, G.; Biscara, L.; Crosta, X.; Eynaud, F.; Malaizé, B.; Revel, M.; Aleman, N.; Barusseau, J.-P.; Vernet, R.; Lopez, S.; Grousset, F.
2015-11-01
The Sahara experienced several humid episodes during the late Quaternary, associated with the development of vast fluvial networks and enhanced freshwater delivery to the surrounding ocean margins. In particular, marine sediment records off Western Sahara indicate deposition of river-borne material at those times, implying sustained fluvial discharges along the West African margin. Today, however, no major river exists in this area; therefore, the origin of these sediments remains unclear. Here, using orbital radar satellite imagery, we present geomorphological data that reveal the existence of a large buried paleodrainage network on the Mauritanian coast. On the basis of evidence from the literature, we propose that reactivation of this major paleoriver during past humid periods contributed to the delivery of sediments to the Tropical Atlantic margin. This finding provides new insights for the interpretation of terrigenous sediment records off Western Africa, with important implications for our understanding of the paleohydrological history of the Sahara.
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Santhi Baskaran
2010-12-01
Full Text Available Energy consumption is a critical design issue in real-time systems, especially in battery- operated systems. Maintaining high performance, while extending the battery life between charges is an interesting challenge for system designers. Dynamic Voltage Scaling (DVS allows a processor to dynamically change speed and voltage at run time, thereby saving energy by spreading run cycles into idle time.Knowing when to use full power and when not, requires the cooperation of the operating system scheduler. Usually, higher processor voltage and frequency leads to higher system throughput whileenergy reduction can be obtained using lower voltage and frequency. Instead of lowering processorvoltage and frequency as much as possible, energy efficient real-time scheduling adjusts voltage andfrequency according to some optimization criteria, such as low energy consumption or high throughput,while it meets the timing constraints of the real-time tasks. As the quantity and functional complexity ofbattery powered portable devices continues to raise, energy efficient design of such devices has becomeincreasingly important. Many real-time scheduling algorithms have been developed recently to reduceenergy consumption in the portable devices that use DVS capable processors. Extensive power awarescheduling techniques have been published for energy reduction, but most of them have been focusedsolely on reducing the processor energy consumption. While the processor is one of the major powerhungry units in the system, other peripherals such as network interface card, memory banks, disks alsoconsume significant amount of power. Dynamic Power Down (DPD technique is used to reduce energyconsumption by shutting down the processing unit and peripheral devices, when the system is idle. Threealgorithms namely Red Tasks Only (RTO, Blue When Possible (BWP and Red as Late as Possible (RLPare proposed in the literature to schedule the real-time tasks in Weakly-hard real-time systems. Thispaper proposes optimal slack management algorithms to make the above existing weakly hard real-timescheduling algorithms energy efficient using DVS and DPD techniques.
Perruisseau-Carrier, Julien
2007-01-01
As a result of the ever growing number of functionalities and standards to be supported by communication systems, as well as the constant development of radar and imaging technologies, a key research area in the field of microwaves and millimeter waves is the achievement of reconfigurability capabilities. In recent years, the progress of MicroElectroMechanical Systems (MEMS) fabrication techniques has allowed radically challenging the performances of reconfigurable devices based on establishe...
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D Manzoori
2009-12-01
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.
Oliveira Damazio, Denis; The ATLAS collaboration
2013-01-01
The first long period of data taking of the Large Hadron Collider was finished after 3 years of work in February 2013. The increase of the instantaneous luminosity by more than six orders of magnitude documents impressively the extraordinary success of this running period enabling the ATLAS experiment to collect very high quality data. However, to ensure a constant and reliable monitoring and data quality assessment from the trigger's point of view, a highly flexible and powerful software framework is essential, covering many different aspects. Aside from drastically changing beam conditions as e.g. increasing pile up, the monitoring frame work has to follow up immediately and in a flexible manner all developments of the TDAQ system. The TDAQ monitoring system of ATLAS covers very different aspects as rate measurements, trigger configuration and software tests, data quality assessment and handling of events where the trigger decision has failed. Especially the data quality assessment must be made coherent at ...
Damazio, D O; The ATLAS collaboration
2013-01-01
The first long period of data taking of the Large Hadron Collider was finished after 2 years of data in February 2013. The increase of the instantaneous luminosity by more than six orders of magnitude documents impressively the extraordinary success of this running period enabling the ATLAS experiment to collect data of very high quality. However, to ensure a constant and reliable monitoring and data quality assessment of the trigger's point of view, a highly flexible and powerful software framework is essential, covering many different aspects. Aside from drastically changing beam conditions as e.g. increasing pile up, the monitoring frame work has to follow up immediately and flexible all developments of the TDAQ system. The TDAQ monitoring system of ATLAS covers very different aspects as rate measurements, trigger configuration and software tests, data quality assessment and handling of events where the trigger decision has failed. Especially the data quality assessment must be made coherent at the online ...
Long, Zi-Xuan; Zhang, Yi
2014-11-01
This paper focuses on the Noether symmetries and the conserved quantities for both holonomic and nonholonomic systems based on a new non-conservative dynamical model introduced by El-Nabulsi. First, the El-Nabulsi dynamical model which is based on a fractional integral extended by periodic laws is introduced, and El-Nabulsiâ€”Hamilton's canonical equations for non-conservative Hamilton system with holonomic or nonholonomic constraints are established. Second, the definitions and criteria of El-Nabulsiâ€”Noether symmetrical transformations and quasi-symmetrical transformations are presented in terms of the invariance of El-Nabulsiâ€”Hamilton action under the infinitesimal transformations of the group. Finally, Noether's theorems for the non-conservative Hamilton system under the El-Nabulsi dynamical system are established, which reveal the relationship between the Noether symmetry and the conserved quantity of the system.
Fuel Cell/Battery Powered Bus System. Final Report for period August 1987 - December 31, 1997
Energy Technology Data Exchange (ETDEWEB)
Wimmer, R.
1999-01-01
Today, fuel cell systems are getting much attention from the automotive industry as a future replacement for the internal combustion engine (ICE). Every US automobile manufacturer and most foreign firms have major programs underway to develop fuel cell engines for transportation. The objective of this program was to investigate the feasibility of using fuel cells as an alternative to the ICE. Three such vehicles (30-foot buses) were introduced beginning in 1994. Extensive development and operational testing of fuel cell systems as a vehicle power source has been accomplished under this program. The development activity investigated total systems configuration and effectiveness for vehicle operations. Operational testing included vehicle performance testing, road operations, and extensive dynamometer emissions testing.
International Nuclear Information System (INIS)
The test interval and the test procedure are the main factors that are related to the reliability of the emergency core cooling system in a nuclear power plant. A method is proposed to specify the allowable ranges of the test intervals for the minimal cut sets in the emergency core cooling system; lower and upper limits of test intervals are selected to minimize unavailability and to assure the unavailability goal respectively. A method is also proposed to determine test procedure. All patterns of test procedure for the emergency core cooling system are generated in the allowable ranges of test intervals, and the test procedure is selected to maximize the index (minus log. of (unavailability over unavailability goal), all devided by man-hours) for the purpose of both reliability increase and man-hours decrease. (author)
Bott periodicity for Z2 symmetric ground states of gapped free-fermion systems
Kennedy, Ricardo
2014-01-01
Building on the symmetry classification of disordered fermions, we give a proof of the proposal by Kitaev, and others, for a "Bott clock" topological classification of free-fermion ground states of gapped systems with symmetries. Our approach differs from previous ones in that (i) we work in the standard framework of Hermitian quantum mechanics over the complex numbers, (ii) we directly formulate a mathematical model for ground states rather than spectrally flattened Hamiltonians, and (iii) we use homotopy-theoretic tools rather than K-theory. Key to our proof is a natural transformation that squares to the standard Bott map and relates the ground state of a d-dimensional system in symmetry class s to the ground state of a (d+1)-dimensional system in symmetry class s+1. This relation gives a new vantage point on topological insulators and superconductors.
A flare-like event from the short-period system XY UMa
International Nuclear Information System (INIS)
The rapidly annually changing XY UMa has been reobserved. A flare-like episode was detected on 31 January 1982 (UT). The flare duration was about 30 minutes. At peak, the system magnitude was U=10.59, B=10.33, V=9.55, and R=8.88. Relative to the average light curve of the system, the apparent magnitude increase was 0.33 at U, 0.13 at B, and 0.09 at V. To look at the event in its intensity profile, the authors converted magnitudes to fluxes and integrated over its duration. From the spectral types of the stars, they estimated a distance of 84 pc to the system and calculated the mean and integrated energies. (Auth.)
Directory of Open Access Journals (Sweden)
Ranjeet
2014-05-01
Full Text Available Systemic lupus erythematosus, referred to as SLE or lupus, is sometimes called the “great imitator.” Why? Because of its wide range of symptoms, people often confuse lupus with other health problems. We report the case of a 22-year-old woman who presented with a flaccid paralysis of limbs due to severe hypokalemia as a consequence of distal renal tubular acidosis (dRTA. A search for the cause of dRTA revealed latent Systemic Lupus Erythematosus (SLE. SLE presenting as dRTA is uncommon
Time-periodic solutions to the full Navier--Stokes--Fourier system with radiation on the boundary
Axmann, Simon; Pokorny, Milan
2014-01-01
The Navier-Stokes-Fourier system is a well established model for describing the motion of viscous compressible heat-conducting fluids. We study the existence of time-periodic weak solutions and improve the known result in the following sense: we extend the class of pressure functions (i.e. consider lower exponent $\\gamma$) and include also the effect of radiation on the boundary.
FERGANY, Hala A.
2005-01-01
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...
Naglaa H. El-Sodany
2011-01-01
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...
Huynh, Khac Tuan; Barros, Anne; Berenguer, Christophe; Castro, Inma,
2011-01-01
This paper deals with the condition-based maintenance of single-unit systems which are subject to the competing and dependent failures due deterioration and traumatic shock events. The main aim is to provide a model to assess the value of condition monitoring information for the maintenance decision-making. A condition-based periodic inspection/replacement policy is developed and compared with a benchmark time-based block replacement policy. Numerical results show that it is indeed useful to ...
Kikugawa, Gota; Nakano, Takeo; Ohara, Taku
2015-07-14
In the present study, we use molecular dynamics (MD) simulations to provide an insight into the system size effect on the self-diffusion coefficient of liquids in the periodic rectangular parallelepiped system, from the hydrodynamic perspective. We have previously shown that in the rectangular box system, the diffusivity exhibits anomalous behaviors, i.e., the diffusion tensor appears to be anisotropic despite the bulk liquid simulation and the diffusion component in the direction along the short side of rectangular box with a high aspect ratio exceeding the diffusivity in the infinite system [Kikugawa et al., J.Chem. Phys. 142, 024503 (2015)]. So far, the size effect on the diffusivity has been intensively studied in the cubic system and has been interpreted quite well by the theoretical considerations employing the hydrodynamic interaction. Here, we have extended the hydrodynamic theory to be applied to periodic rectangular box systems and compared the theoretical predictions with MD simulation results. As a result, the diffusivity predicted by the hydrodynamic theory shows good agreement with the MD results. In addition, the system size effect was examined in a rod-shaped rectangular box in which the two shorter side lengths were equivalent and a film-type rectangular box in which the two longer side lengths were equivalent. It is of interest that we found that the aspect ratio, at which the diffusivity coincides with that in the infinite system, is a universal constant independent of the cross-sectional area for the rod system or the thickness for the film system. By extracting the universal structure in the hydrodynamic description, we also suggested a simplified approximate model to accurately predict the size effect on the diffusivity over a practical range of aspect ratios. PMID:26178118
The Earth-Moon system during the Late Heavy Bombardment period
Jorgensen, Uffe Graae; Hatsukawa, Yuichi; Frei, Robert; Oshima, Masumi; Toh, Yosuke; Kimura, Atsushi
2009-01-01
The Late Heavy Bombardment (LHB) period is the narrow time interval between 3.8 and 3.9 Gyr ago, where the bulk of the craters we see on the Moon formed. Even more craters formed on the Earth. During a field expedition to the 3.8 Gyr old Isua greenstone belt in Greenland, we sampled three types of metasedimentary rocks, that contain direct traces of the LHB impactors by a seven times enrichment (150 ppt) in iridium compared to present day ocean crust (20 ppt). We show that this enrichment is in agreement with the lunar cratering rate, providing the impactors were comets, but not if they were asteroids. Our study is a first direct indication of the nature of the LHB impactors, and the first to find an agreement between the LHB lunar cratering rate and the Earth's early geochemical record (and the corresponding lunar record). The LHB comets that delivered the iridium we see at Isua will at the same time have delivered the equivalent of a km deep ocean, and we explain why one should expect a cometary ocean to be...
System size dependence of the log-periodic oscillations of transverse momentum spectra
Rybczynski, Maciej; Wlodarczyk, Zbigniew
2014-01-01
Recently the inclusive transverse momentum distributions of primary charged particles were measured for different centralities in $Pb+Pb$ collisions. A strong suppression of the nuclear modification factor in central collisions around $p_T \\sim 6-7$ GeV/c was seen. As a possible explanation, the hydrodynamic description of the collision process was tentatively proposed. However, such effect, (albeit much weaker) also exists in the ratio of data/fits, both in nuclear $Pb+Pb$ collisions, and in the elementary $p+p$ data in the same range of transverse momenta for which such an explanation is doubtful. As shown recently, in this case, assuming that this effect is genuine, it can be attributed to a specific modification of a quasi-power like formula usually used to describe such $p_T$ data, namely the Tsallis distribution. Following examples from other branches of physics, one simply has to allow for the power index becoming a complex number. This results in specific log-periodic oscillations dressing the usual p...
Double scale expansion of periodic solutions of some vibrating systems, with non linear springs
Brahim, Nadia Ben
2013-01-01
We consider small solutions of a system with smooth non-linearities for which we provide an approximate solution by using double scale technique; a rigorous proof of convergence of the double scale method is included; for the forced response, a stability result is needed in order to prove convergence in a neighborhood of a primary resonance.
The First Running Period of the CMS Detector Controls System - A Success Story
Glege, F; Chaze, O; Cittolin, S; Coarasa, J A; Deldicque, C; Dobson, M; Gigi, D; Gomez-Reino, R; Hartl, C; Masetti, L; Meijers, F; Meschi, E; Morovic, S; Nunez-Barranco-Fernandez, C; Orsini, L; Ozga, W; Bauer, G; Behrens, U; Branson, J; Holzner, A; Erhan, S; Mommsen, R K; O'Dell, V
2014-01-01
The Detector Control System (DCS) of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) at CERN has been running since the ?rst detector test in summer 2006. It has proven to be robust, ef?cient and easy to maintain.
International Nuclear Information System (INIS)
Proton magnetic resonance spectroscopic, vapor pressure osmometric and Karl Fischer titrimetric measurements have provided support for our earlier findings obtained from interfacial tension and mass transfer experiments that reversed micelles are formed, under certain conditions, in the system HDEHP/n-hexane/CaCl2 solution. These studies were further extended to include different organophosphorus acid (PC 88A), diluent (benzene), and metal ions (Co2+, Ni2+, and Zn2+) to determine whether reversed micellization is a general phenomenon occurring in solvent extraction systems which employ organophosphorus acids. The data obtained so far, suggest that reversed micellization indeed is a general phenomenon operative in organophosphorus acid extractant systems. A new mass transfer cell has been constructed in order to investigate the metal distribution equilibria and extraction kinetics of Co, Ni and Zn using atomic absorption spectrophotometric technique. A quasi-elastic light-scattering apparatus has been installed to investigate aggregation phenomena in solvent extraction systems. Preliminary drop-interface coalescence studies were performed, and the results were correlated with those obtained from interfacial tension measurements. The laser heterodyne light-scattering apparatus for measurement of interfacial viscoelastic properties also has been set-up and is being optimized for high resolution measurements. 21 refs., 16 figs
Koziorowska-Gilun, M; Szurnicka, M; Dziekonska, A; Kordan, W; GiÅ¼ejewski, Z; Filipowicz, K
2016-04-01
The objective of this study was to make the preliminary characterization of the antioxidant defence systems of the yellow fraction (YF) of red deer's (Cervus elaphus L.) semen during the rutting period. The semen was collected using artificial vagina (AV). The studies included spectrophotometric determination of antioxidant enzymes activities such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). We also analysed the contents of low-molecular antioxidants such as L-glutathione (GSHÂ +Â GSSG), L-ascorbate (ASC) and total antioxidant status (TAS). Additionally, the samples were subjected to PAGE and stained for SOD and GPx activities. It was demonstrated that the yellow fraction exhibited activities of SOD and GPx, with the highest activities in September and October. CAT activity was not detected. Staining for the SOD and GPx activities confirmed three protein bands with SOD activity and one protein band with GPx activity. The content of GSHÂ +Â GSSG was similar in trials dating from October to December contrary to the content of ASC which was high in samples from September and October. The stable rate of TAS was observed during the whole rutting period. The results of this study showed that the YF of red deer semen is equipped with basic battery of antioxidant enzymes comprising SOD and GPx, with the supporting role of GSHÂ +Â GSSG and ASC. Moreover, the samples obtained at the peak of the rutting period occurring from September to October had the highest enzymatic activity in comparison with remaining months of the rutting period, which contributed to the high quality of the semen by preventing it from the formation of oxidative stress during the short period of intense sexual activity of male red deer. The better understanding of the mechanisms of antioxidant defence systems in the YF of deer's semen may contribute to the potential use of this fraction in technology of wild ruminant semen preservation. PMID:26854018
Rousselet, Bernard; Ben Brahim, Nadia
2014-01-01
We consider {\\it small solutions} of a vibrating mechanical system with smooth non-linearities for which we provide an approximate solution by using a triple scale analysis; a rigorous proof of convergence of the triple scale method is included; for the forced response, a stability result is needed in order to prove convergence in a neighbourhood of a primary resonance. The amplitude of the response with respect to the frequency forcing is described and it is related to the ...
Real-time Scheduling of periodic tasks in a monoprocessor system with a rechargeable battery
Chetto, Maryline; El Ghor, Hussein
2009-01-01
We are interested in a real-time computing system that is powered through a rechargeable battery. In this context, two constraints need to be addressed: energy and deadlines. Classical task scheduling, in particular Earliest Deadline First, only accounts for timing parameters of the tasks and conse- quently is not suitable when considering energy constraints. We show here how to modify Earliest Deadline so as to account for the properties of the energy source, capacity of the energy storage a...
Bott periodicity for $Z_2$ symmetric ground states of gapped free-fermion systems
Kennedy, Ricardo; Zirnbauer, Martin R.
2014-01-01
Building on the symmetry classification of disordered fermions, we give a proof of the proposal by Kitaev, and others, for a "Bott clock" topological classification of free-fermion ground states of gapped systems with symmetries. Our approach differs from previous ones in that (i) we work in the standard framework of Hermitian quantum mechanics over the complex numbers, (ii) we directly formulate a mathematical model for ground states rather than spectrally flattened Hamilto...
The hematopoietic system of the acute radiation syndrome reconvalescents in post-accidental period
International Nuclear Information System (INIS)
The state of hemopoietic system has been studied since 1986 up to now in 145 patients who had acute radiation sickness after the Chernobyl accident. We studied clinical, morpho functional, histological, ultrastructural, biophysical, cultural, cytochemical indexes of the hematopoietic elements. The connection between hemopoietic microenvironment and hemopoiesis state was put up. The realization of the hematological disorders as myelodysplastic syndrome testified the most important problem in future
International Nuclear Information System (INIS)
We generalize a new concept of local correction of nonlinearities due to multipole content by giving it a mathematical description. We present a general method which allows for a general reduction of all the distortions produced by a given set of multipole errors. The method can be applied to correct an arbitrary distribution of the errors in any transport system, such as transport lines, linacs, synchrotrons and storage rings. 11 refs., 3 figs., 2 tabs
International Nuclear Information System (INIS)
It is of utmost importance to have a computer code in order to analyze how different parameters (like test duration time) affect the unavailability of safety systems of nuclear. In this context, a study was performed in order to evaluate the model employed by the FRANTIC computer code, which performs detailed calculations on the contribution to the system unavailability originated by hardware failures, component tests and repairs, aiming at considering the influence of different test schemes on the system unavailability. It was shown, by means of the results attained that the numerical model used by the FRANTIC code and the analytical model proposed by APOSTOLAKIS and CHU (4) give unavailability values much similar when the component tests are supposed to be perfect. When a test is supposed to be imperfect (that is, when it may induce a test is supposed to be imperfect (that is, when it may induce a failure on the component being tested), the analytical model presents more conservative results. (author)
Veysset, P; Lherm, M; Roulenc, M; Troquier, C; Bébin, D
2015-12-01
Over the past 23 years (1990 to 2012), French beef cattle farms have expanded in size and increased labour productivity by over 60%, chiefly, though not exclusively, through capital intensification (labour-capital substitution) and simplifying herd feeding practices (more concentrates used). The technical efficiency of beef sector production systems, as measured by the ratio of the volume value (in constant euros) of farm output excluding aids to volume of intermediate consumption, has fallen by nearly 20% while income per worker has held stable thanks to subsidies and the labour productivity gains made. This aggregate technical efficiency of beef cattle systems is positively correlated to feed self-sufficiency, which is in turn negatively correlated to farm and herd size. While volume of farm output per hectare of agricultural area has not changed, forage feed self-sufficiency decreased by 6 percentage points. The continual increase in farm size and labour productivity has come at a cost of lower production-system efficiency - a loss of technical efficiency that 20 years of genetic, technical, technological and knowledge-driven progress has barely managed to offset. PMID:26577645
The effect of colostrum period management on BW and immune system in lambs: from birth to weaning.
Hernández-Castellano, L E; Suárez-Trujillo, A; Martell-Jaizme, D; Cugno, G; Argüello, A; Castro, N
2015-10-01
The aim of this study was to investigate the BW and immune status of lambs reared under natural conditions or under artificial conditions fed two different colostrum amounts. In this study, 60 lambs were randomly divided into groups according to treatment. Twenty lambs remained with their dams (natural rearing (NR) group). Forty lambs were removed from their dams at birth. Lambs were bottle-fed with a pool of sheep colostrum, receiving either 4 g of IgG/kg of BW at birth (C4 group) or 8 g of IgG/kg of BW at birth (C8 group). The total colostrum amount was equally divided into three meals at 2, 14 and 24 h after birth. After this period, lambs were bottle-fed a commercial milk replacer. Blood plasma sample analysis and BW recordings were carried out before feeding at birth and then at 1, 2, 3, 4, 5 and 20 days after birth. Another blood sample analysis and BW recording was carried out when animals reached 10 kg of BW. During weaning (30 days), sampling was carried out every 5 days. Blood plasma was used to determine the concentrations of IgG and IgM and the complement system activity - total and alternative pathways. The NR group showed greater BW than the C4 and C8 groups during milk feeding period, whereas the C4 and C8 groups had greater BW than the NR group at the end of weaning period. The C8 and NR groups had greater plasma IgG and IgM concentrations than the C4 group during milk feeding period. In addition, C4 and C8 groups showed similar IgG concentrations and greater IgM concentrations than the NR group at the end of the weaning period. Complement system activity was greater in the NR group than in the C4 and C8 groups during the first 3 days after birth. In conclusion, lambs fed amounts of colostrum equivalent to 8 g of IgG/kg of BW showed similar immune variables compared to lambs reared under natural conditions, obtaining a greater BW at the end of the weaning period. Nevertheless, this study shows that not only the colostrum amount but also the management during the milk feeding and weaning period, such as stress produced by dam separation, milk quality and suckling frequency, can affect the final immune status of lambs. PMID:26148573
Miller, Mitchell D.; Deacon, Ashley M.
2007-11-01
Crystallographic end-stations require a significant investment in state-of-the-art equipment, as well as a significant effort in software development. The equipment often sits idle during annual maintenance shutdowns. In order to utilize the existing hardware and software during these shutdowns, we installed a sealed-tube microsource X-ray generator in the beamline 9-2 hutch at Stanford Synchrotron Radiation Laboratory (SSRL). A multi-layer optic provides good flux and spectral purity. The small physical size of the source, the long optic to focus distance (635 mm) and the short source to optic distance (65 mm) allowed the use of existing beamline components, without any significant modification. The system replaces a short section of beam pipe upstream of the beam conditioning slits and shutter. The system can be installed and removed from the beamline in less than 1 day. The Joint Center for Structural Genomics (JCSG) and SSRL Structural Molecular Biology group developed the Stanford Automated Mounting (SAM) system and installed it on beamlines at SSRL. The JCSG relies on this system to test crystals for diffraction. The installation of the X-ray microsource in beamline 9-2 allowed crystal screening to continue during SSRL shutdowns. Using a standard screening protocol of two 10 min exposures, separated by a 90° phi rotation, the system was capable of screening up to 400 crystals per week and was left to run unattended for up to 4 days. Over 8200 crystals were screened during the last four SSRL shutdown periods. An X-ray generator can also be useful for ongoing beamline development. Shutdown periods provide easier access to the experimental hardware; however, some tests require beam. The X-ray microsource offers the ability to conduct these tests during periods when users are not scheduled.
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Miller, Mitchell D. [Joint Center for Structural Genomics and Stanford Synchrotron Radiation Laboratory, SLAC, MS 69, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)], E-mail: mmiller@slac.stanford.edu; Deacon, Ashley M. [Joint Center for Structural Genomics and Stanford Synchrotron Radiation Laboratory, SLAC, MS 69, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)
2007-11-11
Crystallographic end-stations require a significant investment in state-of-the-art equipment, as well as a significant effort in software development. The equipment often sits idle during annual maintenance shutdowns. In order to utilize the existing hardware and software during these shutdowns, we installed a sealed-tube microsource X-ray generator in the beamline 9-2 hutch at Stanford Synchrotron Radiation Laboratory (SSRL). A multi-layer optic provides good flux and spectral purity. The small physical size of the source, the long optic to focus distance (635 mm) and the short source to optic distance (65 mm) allowed the use of existing beamline components, without any significant modification. The system replaces a short section of beam pipe upstream of the beam conditioning slits and shutter. The system can be installed and removed from the beamline in less than 1 day. The Joint Center for Structural Genomics (JCSG) and SSRL Structural Molecular Biology group developed the Stanford Automated Mounting (SAM) system and installed it on beamlines at SSRL. The JCSG relies on this system to test crystals for diffraction. The installation of the X-ray microsource in beamline 9-2 allowed crystal screening to continue during SSRL shutdowns. Using a standard screening protocol of two 10 min exposures, separated by a 90{sup o} phi rotation, the system was capable of screening up to 400 crystals per week and was left to run unattended for up to 4 days. Over 8200 crystals were screened during the last four SSRL shutdown periods. An X-ray generator can also be useful for ongoing beamline development. Shutdown periods provide easier access to the experimental hardware; however, some tests require beam. The X-ray microsource offers the ability to conduct these tests during periods when users are not scheduled.
Rousselet, Bernard; Ben Brahim, Nadia
2013-01-01
We consider {\\it small solutions} of a vibrating mechanical system with smooth non-linearities for which we provide an approximate solution by using a triple scale analysis; a rigorous proof of convergence of the triple scale method is included; for the forced response, a stability result is needed in order to prove convergence in a neighbourhood of a primary resonance. The amplitude of the response with respect to the frequency forcing is described and it is related to the frequency of a fre...
Quantum effects on Lagrangian points and displaced periodic orbits in the Earth-Moon system
Battista, Emmanuele; Dell'Agnello, Simone; Esposito, Giampiero; Simo, Jules
2015-01-01
Recent work in the literature has shown that the one-loop long distance quantum corrections to the Newtonian potential imply tiny but observable effects in the restricted three-body problem of celestial mechanics, i.e., at the Lagrangian libration points of stable equilibrium the planetoid is not exactly at equal distance from the two bodies of large mass, but the Newtonian values of its coordinates are changed by a few millimeters in the Earth-Moon system. First, we assess such a theoretical...
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The conceptual design of an on-line, near-real-time nondestructive assay instrumentation network for the Los Alamos Plutonium Facility is complete. Analysis of instrument history data indicates that the instrument certification procedures need improvement. Analysis of exhaust filter data has led to the derivation of a buildup prediction equation that is a function of throughput. This suggests that development of a generalized model is possible. A number of routine reports are now available from the Plutonium Facility/Los Alamos Safeguards System including inventories and active reports
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Interfacial behavior of extractant molecules and their interaction with metal ions has been investigated. Consideration was also given to the question of microscopic interfaces, i.e., those associated with reversed micelles as well as microemulsions. NMR spectroscopy, fluorescence spectroscopy, quasi-elastic light scattering, vapor pressure osmometry, and Karl-Fischer titrimetry provided support for findings obtained from interfacial tension experiments that reversed micelles are formed, under certain conditions, in the system di(2-ethylhexyl)phosphoric acid (HDEHP)/ n-hexane/CaCl2 solution. These techniques were further extended to include different organophosphorus acids (PC 88A and CYANEX 272), diluent (benzene), and metal ions (Co2+, Ni2+, and Zn2+) to determine whether reversed micellization occurs in solvent extraction systems which employ organophosphorus acids. A preliminary general model of the aggregation mechanism for metal-extractant complexes has been proposed. Also various laser techniques have been used to investigate the structure and dynamics of extractant films. A laser fluorescence apparatus for probing interfacial dynamics is under construction. 64 refs., 29 figs
Mitral restenosis in the early postoperative period of a patient with systemic lupus erythematosus
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Pomerantzeff Pablo Maria Alberto
1999-01-01
Full Text Available A forty eight year old woman, who had undergone mitral comissurotomy and subsequently developed early restenosis, presented with major comissural fusion and verrucous lesions on the cuspid edges of the mitral valve, with normal subvalvar apparatus. Patient did well for the first six months after surgery when she began to present dyspnea on light exertion. A clinical diagnosis of restenosis was made, which was confirmed by an echocardiogram and cardiac catheterization. She underwent surgery, and a stenotic mitral valve with verrucous lesions suggesting Libman-Sacks' endocarditis was found. Because the diagnosis of systemic lupus erythematosus (SLE had not been confirmed at that time, a bovine pericardium bioprosthesis (FISICS-INCOR was implanted. The patient did well in the late follow-up and is now in NYHA Class I .
A Practical Approach to Improve Optical Channel Utilization Period for Hybrid FSO/RF Systems
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Ahmet Akbulut
2014-01-01
Full Text Available In hybrid FSO/RF systems, mostly a hard switching mechanism is preferred in case of the FSO signal level falls below to the predefined threshold. In this work, a computationally simple approach is proposed to increase the utilization of the FSO channels bandwidth advantage. For the channel, clear air conditions have been supposed with the atmospheric turbulence. In this approach, FSO bit rate is adaptively changed to achieve desired BER performance. An IM/DD modulation, OOK (NRZ format has been used to show the benefit of the proposed method. Furthermore, to be more realistic with respect to the atmospheric turbulence variations within a day, some experimental observations have been followed up.
Quantum phase transition and thermodynamic properties of a fourfold magnetic periodic system
Wang, Shuling; Li, Ruixue; Ding, Linjie; Fu, Hua-Hua; Zhu, Si-cong; Ni, Yun; Meng, Yan; Yao, Kailun
2014-12-01
Based on the experimental synthesis of organic compound verdazyl radical ?-3-(2,6-dichlorophenyl)-1,5-diphenylverdazyl, consisting of four antiferromagnetic couplings, we study the magnetic properties and thermodynamic behaviors for different antiferromagnetic interactions using Green’s function theory. Under different fields, there are five regimes containing two gapless phases and three magnetization plateaus (M=0, 1/2 and saturated magnetization) distinguished by four critical lines, which are evidenced by the two-site entanglement entropy and closely related to the energy spectra. In addition, we calculate the susceptibility and specific heat, to demonstrate the low-lying excitations at low temperatures. It will provide guidance for us to synthesize varieties of unconventional magnetic materials, and stimulate future studies on quantum spin systems.
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On the Systematic Error in the Quantum Mechanical Calculations to the Periodic Table of Elements
Khazan, Albert
2011-05-01
The scientists working on the problems of the Periodic Table of Elements regularly attempt to create models of the elements on the basis of the laws of Quantum Mechanics. One even attempted to use the calculation of the dependency ``atomic mass - element's number'' on this basis, in order to extend the Table by introducing two new Periods containing 50 elements each. The hyperbolic law we have found in the Periodic Table allows to find, first, the atomic mass of the last (heaviest stable) element (411.66), then - the number of the protons in it (155). Two functions were compared: the IUPAC 2007 function (elements 80-118) and another one created according the other data (elements 80-224). Both functions have a large deviation of data in No.104-118. Commencing in Period 8, there are three ``shifts'' of atomic mass for 17, 20, and 25 AMU. Also, our analysis manifests that there in all the aforementioned data is a single point with atomic mass 412 and number 155, where the parameters meet each other. This fact verifies our theory (Khazan A. Upper Limit in Mendeleev's Periodic Table - Element No.155. 2nd ed., Svenska fysikarkivet, Stockholm, 2010).
Element separation before matter accretion of solar system planets in the light of the periodic law
International Nuclear Information System (INIS)
The proofs of element separation in protoplanet nebula of Protosolar system have been found. For this purpose the K1/K2 ratios of concentration of elements - chemical analogs in the rock samples of Venus, Earth, Mars and meteorites were compared. The new approach enabled the comparison of K1/K2 of the Earth and meteorites with K1/K2 of Venus and Mars obtained by elemental analysis of their rock samples. It has been found that at J2/J1>1 chemical analogs have K1/K2: on Venus probably less or at least commeasurable, on Mars and, especially in meteorites, considerably (several orders of magnitude) greater than in the Earth rocks (J1 and J2 are charged atoms fractions in photon flux of the Protosun). Other facts, which agree with the relationship K1/K2=f(R), where R is the average distance of a body from the Sun, were found. 41 refs.; 1 fig.; 5 tabs
Finite Elements for a Beam System With Nonlinear Contact Under Periodic Excitation
Hazim, Hamad
2009-01-01
Solar arrays are structures which are connected to satellites; during launch, they are in a folded position and submitted to high vibrations. In order to save mass, the flexibility of the panels is not negligible and they may strike each other; this may damage the structure. To prevent this, rubber snubbers are mounted at well chosen points of the structure; a prestress is applied to the snubber; but it is quite difficult to check the amount of prestress and the snubber may act only on one side; they will be modeled as one sided springs (see figure 2). In this article, some analysis for responses (displacements) in both time and frequency domains for a clamped-clamped Euler-Bernoulli beam model with a spring are presented. This spring can be unilateral or bilateral fixed at a point. The mounting (beam +spring) is fixed on a rigid support which has a sinusoidal motion of constant frequency. The system is also studied in the frequency domain by sweeping frequencies between two fixed values, in order to save the...
Existence of lattice solutions to semilinear elliptic systems with periodic potential
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Nicholas D. Alikakos
2012-01-01
Full Text Available Under the assumption that the potential W is invariant under a general discrete reflection group $G'=TG$ acting on $mathbb{R}^n$, we establish existence of G'-equivariant solutions to $Delta u - W_u(u = 0$, and find an estimate. By taking the size of the cell of the lattice in space domain to infinity, we obtain that these solutions converge to G-equivariant solutions connecting the minima of the potential W along certain directions at infinity. When particularized to the nonlinear harmonic oscillator $u''+alpha sin u=0$, $alpha>0$, the solutions correspond to those in the phase plane above and below the heteroclinic connections, while the G-equivariant solutions captured in the limit correspond to the heteroclinic connections themselves. Our main tool is the G'-positivity of the parabolic semigroup associated with the elliptic system which requires only the hypothesis of symmetry for W. The constructed solutions are positive in the sense that as maps from $mathbb{R}^n$ into itself leave the closure of the fundamental alcove (region invariant.
Quantum phase transition and thermodynamic properties of a fourfold magnetic periodic system
International Nuclear Information System (INIS)
Based on the experimental synthesis of organic compound verdazyl radical ?-3-(2,6-dichlorophenyl)-1,5-diphenylverdazyl, consisting of four antiferromagnetic couplings, we study the magnetic properties and thermodynamic behaviors for different antiferromagnetic interactions using Green’s function theory. Under different fields, there are five regimes containing two gapless phases and three magnetization plateaus (M=0, 1/2 and saturated magnetization) distinguished by four critical lines, which are evidenced by the two-site entanglement entropy and closely related to the energy spectra. In addition, we calculate the susceptibility and specific heat, to demonstrate the low-lying excitations at low temperatures. It will provide guidance for us to synthesize varieties of unconventional magnetic materials, and stimulate future studies on quantum spin systems. - Highlights: • The antiferromagnetic interaction-magnetic field phase diagrams are constructed. • The magnetization per site makes different contribution to the 1/2 plateau. • The spectral functions for different magnetic interactions are studied. • We investigate the gapless or gapped low-lying excitations at low temperatures
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We investigate the singularity structure analysis of the higher-dimensional time-gated Manakov system referring to the (2+1)-dimensional coupled nonlinear Schroedinger (CNLS) equations, and we show that these equations are Painleve-integrable. By means of the Weiss et al.'s methodology, we show the arbitrariness of the expansion coefficients and the consistency of the truncation corresponding to a special Baecklund transformation (BT) of these CNLS equations. In the wake of such transformation, following the Hirota's formalism, we derive a one-soliton solution. Besides, by using the Zakharov-Shabat (ZS) scheme which provides a general Lax-representation of an evolution system, we show that the (2+1)-dimensional CNLS system under interests is completely integrable. Furthermore, using the arbitrariness of the above coefficients, we unearth and investigate a typical spectrum of periodic coherent structures while depicting elastic interactions amongst such patterns. (author)
A condition-based maintenance policy with non-periodic inspections for a two-unit series system
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This paper considers a condition-based maintenance policy for a two-unit deteriorating system. Each unit is subject to gradual deterioration and is monitored by sequential non-periodic inspections. It can be maintained by good as new preventive or corrective replacements. Every inspection or replacement entails a set-up cost and a component-specific unit cost but if actions on the two components are combined, the set-up cost is charged only once. A parametric maintenance decision framework is proposed to coordinate inspection/replacement of the two components and minimize the long-run maintenance cost of the system. A stochastic model is developed on the basis of the semi-regenerative properties of the maintained system state and the associated cost model is used to assess and optimize the performance of the maintenance model. Numerical experiments emphasize the interest of a control of the operation groupings
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This paper deals with the condition-based maintenance of single-unit systems which are subject to the competing and dependent failures due deterioration and traumatic shock events. The main aim is to provide a model to assess the value of condition monitoring information for the maintenance decision-making. A condition-based periodic inspection/replacement policy is developed and compared with a benchmark time-based block replacement policy. Numerical results show that it is indeed useful to follow closely the actual evolution of the system to adapt the maintenance decisions to the true system state to improve the performance of maintenance policies. The analysis of the maintenance costs savings can be used to justify or not the choice to implement a policy based on condition monitoring information and to invest in condition monitoring devices.
Palladino, Christie Lancaster; Singh, Vijay; Campbell, Jacquelyn; Flynn, Heather; Gold, Katherine
2012-01-01
Objective Homicide and suicide are two important and potentially preventable causes of maternal injury. We analyzed data from the National Violent Death Reporting System to estimate the rates of pregnancy-associated homicide and suicide in a multi-state sample, to compare these rates with other causes of maternal mortality, and to describe victims’ demographic characteristics. Methods We analyzed data from female victims of reproductive age from 2003–2007. We identified pregnancy-associated violent deaths as deaths due to homicide or suicide during pregnancy or within the first year postpartum. We calculated the rates of pregnancy-associated homicide and suicide as the number of deaths per 100,000 live births in the sample population. We used descriptive statistics to report victims’ demographic characteristics and prevalence of intimate partner violence (IPV). Results There were 94 counts of pregnancy-associated suicide and 139 counts of pregnancy-associated homicide, yielding pregnancy-associated suicide and homicide rates of 2.0 and 2.9 deaths/100,000 live births, respectively. Victims of pregnancy-associated suicide were significantly more likely to be older and of Caucasian or American Indian descent as compared to all live births in NVDRS states. Pregnancy-associated homicide victims were significantly more likely to be at the extremes of the age range and African American. 54.3% of pregnancy-associated suicides involved intimate partner conflict that appeared to contribute to the suicide. 45.3% of pregnancy-associated homicides were IPV-associated. Conclusions Our results indicate that pregnancy-associated homicide and suicide are important contributors to maternal mortality and confirm the need to evaluate the relationships between socio demographic disparities and IPV with pregnancy-associated violent death. PMID:22015873