Investigation of eclipsing binary stars exhibiting calcium II emission

International Nuclear Information System (INIS)

Oliver, J.P.

1974-01-01

Three color photometry of some eclipsing binaries showing Calcium II emission is reported. A highly stable and accurate d.c. amplifier, and a new type digital averaging system are described. Past and current light curves of SS Boo, RS CVn, WY Cnc, WW Dra, UV Psc, Z Her, SS Cam, RW UMa, AR Lac, and RT Lac are discussed with particular emphasis on asymmetries in the heights of the maxima and variations in the depths of the minima. Both RS CVn and SS Boo show nearly sinusoidal variation outside eclipse. Spectra of SS Boo and RS CVn are discussed. The suggestion is made that many of these systems belong to a new category of variable eclipsing binary star. It is pointed out that most double line eclipsing binaries with late-type sub-giant secondary components fall into this group, and that many of the characteristics of this group are not easily explained on the basis of existing data and theory. Possible models are discussed and the need for future photometric and spectroscopic study is emphasized. (U.S.)

Interaction between ropinirole hydrochloride and aspirin with human serum albumin as binary and ternary systems by multi-spectroscopic, molecular modeling and zeta potential

International Nuclear Information System (INIS)

Mahaki, Hanie; Memarpoor-Yazdi, Mina; Chamani, Jamshidkhan; Reza Saberi, Mohammad

2013-01-01

The aim of the present study was to describe the competition of ropinirole hydrochloride (RP) and aspirin (ASA) in binding to human serum albumin (HSA) in physiological buffer (pH=7.4) using multi-spectroscopic, molecular modeling and zeta-potential measurements. Fluorescence analysis was used to define the binding and quenching properties of drug-HSA complexes in binary and ternary systems. Fluorescence spectroscopy showed that in the presence of RP, the binding constant of HSA–ASA was increased. Static quenching was confirmed to result in the fluorescence quenching and FRET. The effect of drugs on the conformation of HSA was analyzed using synchronous fluorescence spectroscopy, three-dimensional fluorescence spectra and circular dichroism (CD). The RLS method determined the critical aggregation concentration of drugs on HSA in binary and ternary systems that confirmed the zeta potential results. Structural modeling showed that the affinity of each of the drugs to HSA in binary and ternary systems confirms the spectroscopic results. - Highlights: ► We studied the interaction of ropinirole hydrochloride and aspirin with HSA. ► Molecular modeling and zeta-potential used to describe competitive interaction. ► We determined the critical induced aggregation concentration of both drugs on HSA. ► The binding mechanism of drugs as separate and simultaneous to HSA has been compared. ► The binding site of both drugs as simultaneous effects on HSA has been determined.

Interaction between ropinirole hydrochloride and aspirin with human serum albumin as binary and ternary systems by multi-spectroscopic, molecular modeling and zeta potential

Energy Technology Data Exchange (ETDEWEB)

Mahaki, Hanie, E-mail: hanieh.mahaki@gmail.com [Department of Biology, Faculty of Sciences, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Memarpoor-Yazdi, Mina; Chamani, Jamshidkhan [Department of Biology, Faculty of Sciences, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Reza Saberi, Mohammad [Medical Chemistry Department, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of)

2013-02-15

The aim of the present study was to describe the competition of ropinirole hydrochloride (RP) and aspirin (ASA) in binding to human serum albumin (HSA) in physiological buffer (pH=7.4) using multi-spectroscopic, molecular modeling and zeta-potential measurements. Fluorescence analysis was used to define the binding and quenching properties of drug-HSA complexes in binary and ternary systems. Fluorescence spectroscopy showed that in the presence of RP, the binding constant of HSA-ASA was increased. Static quenching was confirmed to result in the fluorescence quenching and FRET. The effect of drugs on the conformation of HSA was analyzed using synchronous fluorescence spectroscopy, three-dimensional fluorescence spectra and circular dichroism (CD). The RLS method determined the critical aggregation concentration of drugs on HSA in binary and ternary systems that confirmed the zeta potential results. Structural modeling showed that the affinity of each of the drugs to HSA in binary and ternary systems confirms the spectroscopic results. - Highlights: Black-Right-Pointing-Pointer We studied the interaction of ropinirole hydrochloride and aspirin with HSA. Black-Right-Pointing-Pointer Molecular modeling and zeta-potential used to describe competitive interaction. Black-Right-Pointing-Pointer We determined the critical induced aggregation concentration of both drugs on HSA. Black-Right-Pointing-Pointer The binding mechanism of drugs as separate and simultaneous to HSA has been compared. Black-Right-Pointing-Pointer The binding site of both drugs as simultaneous effects on HSA has been determined.

Galactic binaries with eLISA

OpenAIRE

Nelemans, G.

2013-01-01

I review what eLISA will see from Galactic binaries -- double stars with orbital periods less than a few hours and white dwarf (or neutron star/black hole) components. I discuss the currently known binaries that are guaranteed (or verification) sources and explain why the expected total number of eLISA Galactic binaries is several thousand, even though there are large uncertainties in our knowledge of this population, in particular that of the interacting AM CVn systems. I very briefly sketch...

Z CVn - Still mysterious

Science.gov (United States)

Skarka, M.; Liška, J.; Dřevěný, R.; Sódor, Á.; Barnes, T.; Kolenberg, K.

2018-04-01

We comment on short- and long-term pulsation period variations of Z CVn, a classical RR Lyrae star with the Blazhko effect. Z CVn shows cyclic-like O-C diagram that can be interpreted as a consequence of binarity throught the light travel time effect. We show that this hypothesis is false and that the observed long-term period variations must be caused by some effect that is intrinsic to the star. We also show that the Blazhko period is not simply anti-correlated with the long-term period variations as was suggested by previous authors.

Close binary stars

International Nuclear Information System (INIS)

Larsson-Leander, G.

1979-01-01

Studies of close binary stars are being persued more vigorously than ever, with about 3000 research papers and notes pertaining to the field being published during the triennium 1976-1978. Many major advances and spectacular discoveries were made, mostly due to increased observational efficiency and precision, especially in the X-ray, radio, and ultraviolet domains. Progress reports are presented in the following areas: observational techniques, methods of analyzing light curves, observational data, physical data, structure and models of close binaries, statistical investigations, and origin and evolution of close binaries. Reports from the Coordinates Programs Committee, the Committee for Extra-Terrestrial Observations and the Working Group on RS CVn binaries are included. (Auth./C.F.)

ORBITAL EVOLUTION OF COMPACT WHITE DWARF BINARIES

Energy Technology Data Exchange (ETDEWEB)

Kaplan, David L. [Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI 53211 (United States); Bildsten, Lars [Kavli Institute for Theoretical Physics and Department of Physics, Kohn Hall, University of California, Santa Barbara, CA 93106 (United States); Steinfadt, Justin D. R., E-mail: kaplan@uwm.edu, E-mail: bildsten@kitp.ucsb.edu, E-mail: jdrsteinfadt@gmail.com [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93106 (United States)

2012-10-10

The newfound prevalence of extremely low mass (ELM, M{sub He} < 0.2 M{sub Sun }) helium white dwarfs (WDs) in tight binaries with more massive WDs has raised our interest in understanding the nature of their mass transfer. Possessing small (M{sub env} {approx} 10{sup -3} M{sub Sun }) but thick hydrogen envelopes, these objects have larger radii than cold WDs and so initiate mass transfer of H-rich material at orbital periods of 6-10 minutes. Building on the original work of D'Antona et al., we confirm the 10{sup 6} yr period of continued inspiral with mass transfer of H-rich matter and highlight the fact that the inspiraling direct-impact double WD binary HM Cancri likely has an ELM WD donor. The ELM WDs have less of a radius expansion under mass loss, thus enabling a larger range of donor masses that can stably transfer matter and become a He mass transferring AM CVn binary. Even once in the long-lived AM CVn mass transferring stage, these He WDs have larger radii due to their higher entropy from the prolonged H-burning stage.

The period analysis of V418 AQL, SU BOO, RV CVn, CR CAS, GV CYG, V432 PER, and BD+42 2782

International Nuclear Information System (INIS)

Zasche, P.; Wolf, M.; Kučáková, H.; Uhlař, R.

2014-01-01

The minimum timings of eclipsing binaries V418 Aql, SU Boo, RV CVn, CR Cas, GV Cyg, V432 Per, and BD+42 2782 were collected and analyzed. Their long-term behavior was studied via period analysis, revealing a periodic term in eclipse times. We derived 576 new times of minimum. Hence, to describe the periodic variation, a third-body hypothesis was proposed and the resulting orbital periods are as follows: 70, 7.4, 53, 37, 27, 53, and 18 yr, respectively. For the system V432 Per an additional 9.5 yr variation was also found. The predicted minimum masses of these distant bodies were calculated and their detectability discussed. The light curves of SU Boo and RV CVn were analyzed using the PHOEBE program, resulting in physical parameters of the components. New variable stars in the field of V418 Aql were discovered.

Backyard Telescopes Watch an Expanding Binary

Science.gov (United States)

Kohler, Susanna

2018-01-01

What can you do with a team of people armed with backyard telescopes and a decade of patience? Test how binary star systems evolve under Einsteins general theory of relativity!Unusual VariablesCataclysmic variables irregularly brightening binary stars consisting of an accreting white dwarf and a donor star are a favorite target among amateur astronomers: theyre detectable even with small telescopes, and theres a lot we can learn about stellar astrophysics by observing them, if were patient.Diagram of a cataclysmic variable. In an AM CVn, the donor is most likely a white dwarf as well, or a low-mass helium star. [Philip D. Hall]Among the large family of cataclysmic variables is one unusual type: the extremely short-period AM Canum Venaticorum (AM CVn) stars. These rare variables (only 40 are known) are unique in having spectra dominated by helium, suggesting that they contain little or no hydrogen. Because of this, scientists have speculated that the donor stars in these systems are either white dwarfs themselves or very low-mass helium stars.Why study AM CVn stars? Because their unusual configuration allows us to predict the behavior of their orbital evolution. According to the general theory of relativity, the two components of an AM CVn will spiral closer and closer as the system loses angular momentum to gravitational-wave emission. Eventually they will get so close that the low-mass companion star overflows its Roche lobe, beginning mass transfer to the white dwarf. At this point, the orbital evolution will reverse and the binary orbit will expand, increasing its period.CBA member Enrique de Miguel, lead author on the study, with his backyard telescope in Huelva, Spain. [Enrique de Miguel]Backyard Astronomy Hard at WorkMeasuring the evolution of an AM CVns orbital period is the best way to confirm this model, but this is no simple task! To observe this evolution, we first need a system with a period that can be very precisely measured best achieved with an

THE ELM SURVEY. V. MERGING MASSIVE WHITE DWARF BINARIES

International Nuclear Information System (INIS)

Brown, Warren R.; Kenyon, Scott J.; Kilic, Mukremin; Gianninas, A.; Allende Prieto, Carlos

2013-01-01

We present the discovery of 17 low-mass white dwarfs (WDs) in short-period (P ≤ 1 day) binaries. Our sample includes four objects with remarkable log g ≅ 5 surface gravities and orbital solutions that require them to be double degenerate binaries. All of the lowest surface gravity WDs have metal lines in their spectra implying long gravitational settling times or ongoing accretion. Notably, six of the WDs in our sample have binary merger times 0.9 M ☉ companions. If the companions are massive WDs, these four binaries will evolve into stable mass transfer AM CVn systems and possibly explode as underluminous supernovae. If the companions are neutron stars, then these may be millisecond pulsar binaries. These discoveries increase the number of detached, double degenerate binaries in the ELM Survey to 54; 31 of these binaries will merge within a Hubble time.

THE ELM SURVEY. V. MERGING MASSIVE WHITE DWARF BINARIES

Energy Technology Data Exchange (ETDEWEB)

Brown, Warren R.; Kenyon, Scott J. [Smithsonian Astrophysical Observatory, 60 Garden St, Cambridge, MA 02138 (United States); Kilic, Mukremin; Gianninas, A. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, OK, 73019 (United States); Allende Prieto, Carlos, E-mail: wbrown@cfa.harvard.edu, E-mail: skenyon@cfa.harvard.edu, E-mail: kilic@ou.edu, E-mail: alexg@nhn.ou.edu, E-mail: callende@iac.es [Instituto de Astrofisica de Canarias, E-38205, La Laguna, Tenerife (Spain)

2013-05-20

We present the discovery of 17 low-mass white dwarfs (WDs) in short-period (P {<=} 1 day) binaries. Our sample includes four objects with remarkable log g {approx_equal} 5 surface gravities and orbital solutions that require them to be double degenerate binaries. All of the lowest surface gravity WDs have metal lines in their spectra implying long gravitational settling times or ongoing accretion. Notably, six of the WDs in our sample have binary merger times <10 Gyr. Four have {approx}>0.9 M{sub Sun} companions. If the companions are massive WDs, these four binaries will evolve into stable mass transfer AM CVn systems and possibly explode as underluminous supernovae. If the companions are neutron stars, then these may be millisecond pulsar binaries. These discoveries increase the number of detached, double degenerate binaries in the ELM Survey to 54; 31 of these binaries will merge within a Hubble time.

A VERY BRIGHT, VERY HOT, AND VERY LONG FLARING EVENT FROM THE M DWARF BINARY SYSTEM DG CVn

Energy Technology Data Exchange (ETDEWEB)

Osten, Rachel A. [Space Telescope Science Institute (United States); Kowalski, Adam [U. Md/GSFC (United States); Drake, Stephen A. [USRA/CRESST and NASA/GSFC (United States); Krimm, Hans [USRA/CRESST (United States); Page, Kim [X-ray and Observational Astronomy Group, Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom); Gazeas, Kosmas [Department of Astrophysics, Astronomy and Mechanics, University of Athens, GR-15784 Zografos, Athens (Greece); Kennea, Jamie [Penn State (United States); Oates, Samantha [Instituto de Astrofsica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, E-18008, Granada (Spain); Page, Mathew [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking RH5 6NT (United Kingdom); De Miguel, Enrique [Departamento de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, E-21071 Huelva (Spain); Novák, Rudolf [Research Centre for Toxic Compounds in the Environment, Faculty of Science, Masaryk University, Kamenice 3, 625 00 Brno (Czech Republic); Apeltauer, Tomas [Brno University of Technology, Faculty of Civil Engineering, Veveri 331/95, 602 00 Brno (Czech Republic); Gehrels, Neil, E-mail: osten@stsci.edu [NASA/GSFC (United States)

2016-12-01

On 2014 April 23, the Swift satellite responded to a hard X-ray transient detected by its Burst Alert Telescope, which turned out to be a stellar flare from a nearby, young M dwarf binary DG CVn. We utilize observations at X-ray, UV, optical, and radio wavelengths to infer the properties of two large flares. The X-ray spectrum of the primary outburst can be described over the 0.3–100 keV bandpass by either a single very high-temperature plasma or a nonthermal thick-target bremsstrahlung model, and we rule out the nonthermal model based on energetic grounds. The temperatures were the highest seen spectroscopically in a stellar flare, at T{sub X} of 290 MK. The first event was followed by a comparably energetic event almost a day later. We constrain the photospheric area involved in each of the two flares to be >10{sup 20} cm{sup 2}, and find evidence from flux ratios in the second event of contributions to the white light flare emission in addition to the usual hot, T  ∼ 10{sup 4} K blackbody emission seen in the impulsive phase of flares. The radiated energy in X-rays and white light reveal these events to be the two most energetic X-ray flares observed from an M dwarf, with X-ray radiated energies in the 0.3–10 keV bandpass of 4 × 10{sup 35} and 9 × 10{sup 35} erg, and optical flare energies at E{sub V} of 2.8 × 10{sup 34} and 5.2 × 10{sup 34} erg, respectively. The results presented here should be integrated into updated modeling of the astrophysical impact of large stellar flares on close-in exoplanetary atmospheres.

A Very Bright, Very Hot, and Very Long Flaring Event from the M Dwarf Binary System DG CVn

Science.gov (United States)

Osten, Rachel A.; Kowalski, Adam; Drake, Stephen; Krimm, Hans; Page, Kim; Gazeas, Kosmas; Page, Mathew; Miguel, Enrique De; Novak, Rudolf; Gehrels, Cornelis

2016-01-01

On 2014 April 23, the Swift satellite responded to a hard X-ray transient detected by its Burst Alert Telescope, which turned out to be a stellar flare from a nearby, young M dwarf binary DG CVn. We utilize observations at X-ray, UV, optical, and radio wavelengths to infer the properties of two large flares. The X-ray spectrum of the primary outburst can be described over the 0.3100 kiloelectron volts bandpass by either a single very high-temperature plasma or a nonthermal thick-target bremsstrahlung model, and we rule out the nonthermal model based on energetic grounds. The temperatures were the highest seen spectroscopically in a stellar flare, at T(sub x) of 290 megakelvin. The first event was followed by a comparably energetic event almost a day later. We constrain the photospheric area involved in each of the two flares to be greater than 10(exp 20) sq cm, and find evidence from flux ratios in the second event of contributions to the white light flare emission in addition to the usual hot, T approximately 10(exp 4) K blackbody emission seen in the impulsive phase of flares. The radiated energy in X-rays and white light reveal these events to be the two most energetic X-ray flares observed from an M dwarf, with X-ray radiated energies in the 0.3-10 kiloelectron volts bandpass of 4 x 10(exp 35) and 9 x 10(exp 35) erg, and optical flare energies at E(sub V) of 2.8 x 10(exp 34) and 5.2 x 10(exp 34) erg, respectively. The results presented here should be integrated into updated modeling of the astrophysical impact of large stellar flares on close-in exoplanetary atmospheres.

Classification of Ap-stars HR 830 and ZI CVn

International Nuclear Information System (INIS)

Zverko, J.

1984-01-01

Two ambiguously classified Ap-stars, HR 830 and 21 CVn, are studied. The observational data are compared with the data for normal stars αDel and αLyr. Star HR 830 is classified as Ap of type Si based on the enhanced absorption in the Si lines and photometric variability in UBV. 21 CVn is classified as Ap Si based on weaker absorption of helium, the variability of helium lines, photometric periodic variability and the properties of the UV spectrum. It is concluded that the photometric periodic variability is a good indicator of Ap-properties of rapidly rotating A and late B stars. (author)

Relativistic double-zeta, triple-zeta, and quadruple-zeta basis sets for the lanthanides La–Lu

NARCIS (Netherlands)

Dyall, K.G.; Gomes, A.S.P.; Visscher, L.

2010-01-01

Relativistic basis sets of double-zeta, triple-zeta, and quadruple-zeta quality have been optimized for the lanthanide elements La-Lu. The basis sets include SCF exponents for the occupied spinors and for the 6p shell, exponents of correlating functions for the valence shells (4f, 5d and 6s) and the

EVOLUTION OF CATACLYSMIC VARIABLES AND RELATED BINARIES CONTAINING A WHITE DWARF

International Nuclear Information System (INIS)

Kalomeni, B.; Rappaport, S.; Molnar, M.; Nelson, L.; Quintin, J.; Yakut, K.

2016-01-01

We present a binary evolution study of cataclysmic variables (CVs) and related systems with white dwarf (WD) accretors, including for example, AM CVn systems, classical novae, supersoft X-ray sources (SXSs), and systems with giant donor stars. Our approach intentionally avoids the complications associated with population synthesis algorithms, thereby allowing us to present the first truly comprehensive exploration of all of the subsequent binary evolution pathways that zero-age CVs might follow (assuming fully non-conservative, Roche-lobe overflow onto an accreting WD) using the sophisticated binary stellar evolution code MESA. The grid consists of 56,000 initial models, including 14 WD accretor masses, 43 donor-star masses (0.1–4.7 M ⊙ ), and 100 orbital periods. We explore evolution tracks in the orbital period and donor-mass ( P orb – M don ) plane in terms of evolution dwell times, masses of the WD accretor, accretion rate, and chemical composition of the center and surface of the donor star. We report on the differences among the standard CV tracks, those with giant donor stars, and ultrashort period systems. We show where in parameter space one can expect to find SXSs, present a diagnostic to distinguish among different evolutionary paths to forming AM CVn binaries, quantify how the minimum orbital period in CVs depends on the chemical composition of the donor star, and update the P orb ( M wd ) relation for binaries containing WDs whose progenitors lost their envelopes via stable Roche-lobe overflow. Finally, we indicate where in the P orb – M don the accretion disks will tend to be stable against the thermal-viscous instability, and where gravitational radiation signatures may be found with LISA.

Power spectra decomposition of 36 RS CVn UBV photometric light curves from the first two years of the automatic photoelectric telescope

International Nuclear Information System (INIS)

Nelson, E.R.

1988-01-01

The first search for multiple periodic structure of a major subset of the RS CVn class of interacting binary stars systems, using a rigorous numerical approach appropriate to unevenly-spaced gapped data, is presented. The main intent of this dissertation is to characterize properly the power spectral content of RS CVn binary light curves and describe how this information can constrain the current models for the systems. If the light curve can be considered as a tracer of stellar surface activity, then the photometric distortions can be used to characterize magnetic activity cycles and add to the understanding of stellar dynamics. Most of the systems exhibit multiple periodic structure, 40% of which show changes in the photometric period on a time scale of a few hundred days. A preference is observed for photometric periods with time scales near the orbital and half orbital periods. The effect is particularly strong for the shorter period systems and is interpreted as evidence for synchronous, or near synchronous, rotation. A strong linear correlation in the periods for the multiply periodic systems is observed which indicates a preferential pairing of spot groups on the stellar surface. No correlation is found for the relative phases of the multiple periodic signals. Changes in the photometric period are associated with variations in the amplitude of the distortion wave, which would indicate the growth and decay of spot groups. The growth and decay of pairs of spot groups, arbitrarily separated in phase, on a differentially rotating star is the model most consistent with the results of my analysis

Close Binaries in the 21st Century: New Opportunities and Challenges

CERN Document Server

Giménez, Àlvaro; Niarchos, Panagiotis; Rucinski, Slavek

2006-01-01

An International Conference entitled "Close Binaries in the 21st Century: New Opportunities and Challenges", was held in Syros island, Greece, from 27 to 30 June, 2005. There are many binary star systems whose components are so close together, that they interact in various ways. Stars in such systems do not pass through all stages of their evolution independently of each other; in fact their evolutionary path is significantly affected by their companions. Processes of interaction include gravitational effects, mutual irradiation, mass exchange, mass loss from the system, phenomena of extended atmospheres, semi-transparent atmospheric clouds, variable thickness disks and gas streams. The zoo of Close Binary Systems includes: Close Eclipsing Binaries (Detached, Semi-detached, Contact), High and Low-Mass X-ray Binaries, Cataclysmic Variables, RS CVn systems, Pulsar Binaries and Symbiotic Stars. The study of these binaries triggered the development of new branches of astrophysics dealing with the structure and ev...

Navy Ford (CVN-78) Class Aircraft Carrier Program: Background and Issues for Congress

Science.gov (United States)

2013-10-22

states: The CVN 78 is experiencing cost growth due to “first of class” material availability (i.e., valves, actuators ), construction labor...assessment during IOT &E [initial operational test and evaluation]. • The current TEMP [test and evaluation master plan] does not adequately address...developmental testing significantly raises the likelihood of the discovery of platform-level problems during IOT &E. • The Navy plans to deliver CVN-78 in

Convection Enhances Magnetic Turbulence in AM CVn Accretion Disks

Science.gov (United States)

Coleman, Matthew S. B.; Blaes, Omer; Hirose, Shigenobu; Hauschildt, Peter H.

2018-04-01

We present the results of local, vertically stratified, radiation magnetohydrodynamic shearing-box simulations of magnetorotational instability (MRI) turbulence for a (hydrogen poor) composition applicable to accretion disks in AM CVn type systems. Many of these accreting white dwarf systems are helium analogs of dwarf novae (DNe). We utilize frequency-integrated opacity and equation-of-state tables appropriate for this regime to accurately portray the relevant thermodynamics. We find bistability of thermal equilibria in the effective-temperature, surface-mass-density plane typically associated with disk instabilities. Along this equilibrium curve (i.e., the S-curve), we find that the stress to thermal pressure ratio α varied with peak values of ∼0.15 near the tip of the upper branch. Similar to DNe, we found enhancement of α near the tip of the upper branch caused by convection; this increase in α occurred despite our choice of zero net vertical magnetic flux. Two notable differences we find between DN and AM CVn accretion disk simulations are that AM CVn disks are capable of exhibiting persistent convection in outburst, and ideal MHD is valid throughout quiescence for AM CVns. In contrast, DNe simulations only show intermittent convection, and nonideal MHD effects are likely important in quiescence. By combining our previous work with these new results, we also find that convective enhancement of the MRI is anticorrelated with mean molecular weight.

EVOLUTION OF CATACLYSMIC VARIABLES AND RELATED BINARIES CONTAINING A WHITE DWARF

Energy Technology Data Exchange (ETDEWEB)

Kalomeni, B.; Rappaport, S.; Molnar, M. [Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Nelson, L. [Department of Physics, Bishop’s University, 2600 College St., Sherbrooke, Quebec, QC J1M 1Z7 (Canada); Quintin, J. [Department of Physics, McGill University, Montréal, QC H3A 2T8 (Canada); Yakut, K., E-mail: kalomeni@mit.edu, E-mail: sar@mit.edu, E-mail: momchil.molnar@gmail.com, E-mail: belinda.kalomeni@ege.edu.tr, E-mail: kadri.yakut@ege.edu.tr, E-mail: lnelson@ubishops.ca, E-mail: jquintin@physics.mcgill.ca [Department of Astronomy and Space Sciences, Ege University, 35100, İzmir (Turkey)

2016-12-10

We present a binary evolution study of cataclysmic variables (CVs) and related systems with white dwarf (WD) accretors, including for example, AM CVn systems, classical novae, supersoft X-ray sources (SXSs), and systems with giant donor stars. Our approach intentionally avoids the complications associated with population synthesis algorithms, thereby allowing us to present the first truly comprehensive exploration of all of the subsequent binary evolution pathways that zero-age CVs might follow (assuming fully non-conservative, Roche-lobe overflow onto an accreting WD) using the sophisticated binary stellar evolution code MESA. The grid consists of 56,000 initial models, including 14 WD accretor masses, 43 donor-star masses (0.1–4.7 M {sub ⊙}), and 100 orbital periods. We explore evolution tracks in the orbital period and donor-mass ( P {sub orb}– M {sub don}) plane in terms of evolution dwell times, masses of the WD accretor, accretion rate, and chemical composition of the center and surface of the donor star. We report on the differences among the standard CV tracks, those with giant donor stars, and ultrashort period systems. We show where in parameter space one can expect to find SXSs, present a diagnostic to distinguish among different evolutionary paths to forming AM CVn binaries, quantify how the minimum orbital period in CVs depends on the chemical composition of the donor star, and update the P {sub orb}( M {sub wd}) relation for binaries containing WDs whose progenitors lost their envelopes via stable Roche-lobe overflow. Finally, we indicate where in the P {sub orb}– M {sub don} the accretion disks will tend to be stable against the thermal-viscous instability, and where gravitational radiation signatures may be found with LISA.

SHPL: The Scaleable High-Performance LAN on the CVN 71

National Research Council Canada - National Science Library

Blackwell, L

1998-01-01

...) Core Technology Program aboard USS Theodore Roosevelt (CVN-71). The program demonstrates advanced concepts in strike planning, visualization, and execution using the latest technology in high speed computing, 3-D graphics, and networking...

DOUBLE-LINED SPECTROSCOPIC BINARY STARS IN THE RAVE SURVEY

International Nuclear Information System (INIS)

Matijevic, G.; Zwitter, T.; Munari, U.; Siviero, A.; Bienayme, O.; Siebert, A.; Binney, J.; Bland-Hawthorn, J.; Boeche, C.; Steinmetz, M.; Campbell, R.; Freeman, K. C.; Gibson, B.; Gilmore, G.; Grebel, E. K.; Helmi, A.; Navarro, J. F.; Parker, Q. A.; Seabroke, G. M.; Watson, F. G.

2010-01-01

We devise a new method for the detection of double-lined binary stars in a sample of the Radial Velocity Experiment (RAVE) survey spectra. The method is both tested against extensive simulations based on synthetic spectra and compared to direct visual inspection of all RAVE spectra. It is based on the properties and shape of the cross-correlation function, and is able to recover ∼80% of all binaries with an orbital period of order 1 day. Systems with periods up to 1 yr are still within the detection reach. We have applied the method to 25,850 spectra of the RAVE second data release and found 123 double-lined binary candidates, only eight of which are already marked as binaries in the SIMBAD database. Among the candidates, there are seven that show spectral features consistent with the RS CVn type (solar type with active chromosphere) and seven that might be of W UMa type (over-contact binaries). One star, HD 101167, seems to be a triple system composed of three nearly identical G-type dwarfs. The tested classification method could also be applicable to the data of the upcoming Gaia mission.

Test of post-newtonian conservation laws in the binary system PSR 1913+16

International Nuclear Information System (INIS)

Will, C.M.

1976-01-01

Observations that set upper limits on secular changes in the pulsar period and orbital period in the binary system PSR 1913+16 may provide a test of post-Newtonian conservation laws. According to some metric theories of gravitation, the center of mass of a binary system may be accelerated in the direction of the periastron of the orbit because of a violation of post-Newtonian momentum conservation. In the binary system PSR 1913+16, this effect could produce secular changes in both pulsar and orbital periods (changing overall Doppler shift) as large as two parts in 10 6 per year. The size of the effect is proportional to the sine of the angle of periastron, to the difference in the masses of the components of the binary system, and to the combination of parametrized post-Newtonian parameters α 3 +zeta 2 -zeta/subw/. This combination is zero in any theory that predicts conserved total momentum for isolated systems (including general relativity and Brans-Dicke theory). Although solar-system experiments constrain α 3 and zeta/subw/ to be small, no decent direct limit has been placed on zeta 2 . Other possible sources of secular period changes in PSR 1913+16 are discussed and compared with this effect. It is also shown that a breakdown in the equality of active and passive gravitational masses (violation of ''Newton's third law'') leads only to periodic, unobservable orbital effects in a system like PSR 1913+16

Comparison of methods of zeta potential and residual turbidity of pectin solutions using calcium sulphate/aluminium sulphate as a precipitant

Directory of Open Access Journals (Sweden)

Kuljanin Tatjana A.

2017-01-01

Full Text Available The affinity of calcium ion binding from CaO used in the most common process of purification of sugar beet juice is relatively low. Therefore, large amounts of this compound are required. This paper presents the theoretical basis of a novel sugar beet juice purification method based on the application of the binary system CaSO4/Al2(SO4 . In order to monitor the process of coagulation and precipitation of pectin in the presence of CaSO4/Al2(SO43, two methods were compared: measurement of the zeta potential and of residual solution turbidity. The zeta potential of pectin solution was determined by electrophoretic method, while the residual turbidity was determined by spectrophotometry. Two model solutions of pectin (0.1 % w/w were investigated. Studies were performed with 10 different concentrations of the binary solution CaSO4/Al2(SO43 (50 - 500 g dm-3. The amount of the precipitant CaSO4/Al2(SO43 (1:1 w/w needed to achieve the minimum solution turbidity and charge neutralization of pectin particles (zero zeta potential were measured and compared. Colloidal destabilization occurred before a complete neutralization of the surface charge of pectin particles (zeta potential ~ 0 mV. Optimal quantities (490 - 705 mg g-1 pectin of the applied binary mixture, were obtained using both methods. This is much lower than the amount of CaO that is commonly used in the conventional process of sugar beet juice purification (about 9 g• g-1 pectin. The use of these precipitants could be important from both economic and environmental point of view. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR 31055

THE HOT COMPONENTS OF AM CVn HELIUM CATACLYSMICS

International Nuclear Information System (INIS)

Sion, Edward M.; Godon, Patrick; Ballouz, Ronald-Louis; Linnell, Albert P.

2011-01-01

We present the results of a multi-component synthetic spectral analysis of the archival far-ultraviolet spectra of the hot components of several AM CVn double degenerate interacting binaries with known distances from trigonometric parallaxes. Our analysis was carried out using the code BINSYN, which takes into account the donor companion star, the shock front which forms at the disk edge, and the FUV and NUV energy distribution. We fixed the distance of each system at its parallax-derived value and adopted appropriate values of orbital inclination and white dwarf (WD) mass. We find that the accretion-heated 'DO/DB' WDs are contributing significantly to the FUV flux in five of the systems (ES Ceti, CR Boo, V803 Cen, HP Lib, GP Com). In three of the systems, GP Com, ES Ceti, and CR Boo, the WD dominates the FUV/NUV flux. We present model-derived accretion rates which agree with the low end of the range of accretion rates derived earlier from blackbody fits over the entire spectral energy distribution. We find that the WD in ES Ceti is very likely not a direct impact accretor but has a small disk. The WD in ES Ceti has T eff ∼ 40, 000 ± 10, 000 K. This is far cooler than the previous estimate of Espaillat et al.. We find that the WD in GP Com has T eff = 14, 800 ± 500 K, which is hotter than the previously estimated temperature of 11,000 K. We present a comparison between our empirical results and current theoretical predictions for these systems.

EXOSAT and IUE observations of contact binaries

International Nuclear Information System (INIS)

Vilhu, O.; Heise, J.; Laboratorium voor Ruimteonderzoek, Utrecht, Netherlands)

1986-01-01

EXOSAT observations are reported of the contact binaries W UMa, VW Cep, 44t Boo, XY Leo, and V566 Oph and the detached short-period RS CVn stars ER Vul and HD 209943. Complete X-ray light curves were obtained for W UMa, VW Cep and 44t Boo. Nearly simultaneous IUE observations of VW Cep provide important comparisons of the Mg II emission, the UV continuum, and the FES light curve, pointing to extra hot gas at phase 0.75. The observations indicate that contact binaries have highly structured (in temperature and geometry) and highly variable coronae, not preferentially connected with either of the component stars. The observed dips can be interpreted as due to cool absorbing clouds above localized X-ray emitting regions. For VW Cep, 44t Boo, and XY Leo there is evidence that the neck regions are sites for X-ray-emitting hot gas. 66 references

Multifractal and higher-dimensional zeta functions

International Nuclear Information System (INIS)

Véhel, Jacques Lévy; Mendivil, Franklin

2011-01-01

In this paper, we generalize the zeta function for a fractal string (as in Lapidus and Frankenhuijsen 2006 Fractal Geometry, Complex Dimensions and Zeta Functions: Geometry and Spectra of Fractal Strings (New York: Springer)) in several directions. We first modify the zeta function to be associated with a sequence of covers instead of the usual definition involving gap lengths. This modified zeta function allows us to define both a multifractal zeta function and a zeta function for higher-dimensional fractal sets. In the multifractal case, the critical exponents of the zeta function ζ(q, s) yield the usual multifractal spectrum of the measure. The presence of complex poles for ζ(q, s) indicates oscillations in the continuous partition function of the measure, and thus gives more refined information about the multifractal spectrum of a measure. In the case of a self-similar set in R n , the modified zeta function yields asymptotic information about both the 'box' counting function of the set and the n-dimensional volume of the ε-dilation of the set

Design and assembly of ternary Pt/Re/SnO2 NPs by controlling the zeta potential of individual Pt, Re, and SnO2 NPs

Science.gov (United States)

Drzymała, Elżbieta; Gruzeł, Grzegorz; Pajor-Świerzy, Anna; Depciuch, Joanna; Socha, Robert; Kowal, Andrzej; Warszyński, Piotr; Parlinska-Wojtan, Magdalena

2018-05-01

In this study Pt, Re, and SnO2 nanoparticles (NPs) were combined in a controlled manner into binary and ternary combinations for a possible application for ethanol oxidation. For this purpose, zeta potentials as a function of the pH of the individual NPs solutions were measured. In order to successfully combine the NPs into Pt/SnO2 and Re/SnO2 NPs, the solutions were mixed together at a pH guaranteeing opposite zeta potentials of the metal and oxide NPs. The individually synthesized NPs and their binary/ternary combinations were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning transmission electron microscopy (STEM) combined with energy dispersive X-ray spectroscopy (EDS) analysis. FTIR and XPS spectroscopy showed that the individually synthesized Pt and Re NPs are metallic and the Sn component was oxidized to SnO2. STEM showed that all NPs are well crystallized and the sizes of the Pt, Re, and SnO2 NPs were 2.2, 1.0, and 3.4 nm, respectively. Moreover, EDS analysis confirmed the successful formation of binary Pt/SnO2 and Re/SnO2 NP, as well as ternary Pt/Re/SnO2 NP combinations. This study shows that by controlling the zeta potential of individual metal and oxide NPs, it is possible to assemble them into binary and ternary combinations. [Figure not available: see fulltext.

THE ELM SURVEY. II. TWELVE BINARY WHITE DWARF MERGER SYSTEMS

International Nuclear Information System (INIS)

Kilic, Mukremin; Brown, Warren R.; Kenyon, S. J.; Prieto, Carlos Allende; Agueeros, M. A.; Heinke, Craig

2011-01-01

We describe new radial velocity and X-ray observations of extremely low-mass white dwarfs (ELM WDs, ∼0.2 M sun ) in the Sloan Digital Sky Survey Data Release 4 and the MMT Hypervelocity Star survey. We identify four new short period binaries, including two merger systems. These observations bring the total number of short period binary systems identified in our survey to 20. No main-sequence or neutron star companions are visible in the available optical photometry, radio, and X-ray data. Thus, the companions are most likely WDs. Twelve of these systems will merge within a Hubble time due to gravitational wave radiation. We have now tripled the number of known merging WD systems. We discuss the characteristics of this merger sample and potential links to underluminous supernovae, extreme helium stars, AM CVn systems, and other merger products. We provide new observational tests of the WD mass-period distribution and cooling models for ELM WDs. We also find evidence for a new formation channel for single low-mass WDs through binary mergers of two lower mass objects.

CARA CVN: inherently safe fuel element for PHWR power plants

International Nuclear Information System (INIS)

Brasnarof, Daniel O.; Lestani, Hector A.; Agueda, Horacio C.; Marino, Armando C.; Florido, Pablo C.; Daverio, Hernando

2007-01-01

This paper presents design alternatives of the CARA fuel element with negative void reactivity coefficient (CVN) enhancing the PHWR safety for L-LOCA sequences. This design enhances the safety and the operation performance in Atucha and Embalse without changes in the operation conditions. This new design balances wide performance margins of CARA SEU 0.9% previous design, with new intrinsic safety requirements without economic penalties. (author) [es

Riemann zeta function from wave-packet dynamics

DEFF Research Database (Denmark)

Mack, R.; Dahl, Jens Peder; Moya-Cessa, H.

2010-01-01

We show that the time evolution of a thermal phase state of an anharmonic oscillator with logarithmic energy spectrum is intimately connected to the generalized Riemann zeta function zeta(s, a). Indeed, the autocorrelation function at a time t is determined by zeta (sigma + i tau, a), where sigma...... index of JWKB. We compare and contrast exact and approximate eigenvalues of purely logarithmic potentials. Moreover, we use a numerical method to find a potential which leads to exact logarithmic eigenvalues. We discuss possible realizations of Riemann zeta wave-packet dynamics using cold atoms...

Can Eccentric Debris Disks Be Long-lived? A First Numerical Investigation and Application to Zeta(exp 2) Reticuli

Science.gov (United States)

Faramaz, V.; Beust, H.; Thebault, P.; Augereau, J.-C.; Bonsor, A.; delBurgo, C.; Ertel, S.; Marshall, J. P.; Milli, J.; Montesinos, B.;

Lectures on the Riemann zeta function

CERN Document Server

Iwaniec, H

2014-01-01

The Riemann zeta function was introduced by L. Euler (1737) in connection with questions about the distribution of prime numbers. Later, B. Riemann (1859) derived deeper results about the prime numbers by considering the zeta function in the complex variable. The famous Riemann Hypothesis, asserting that all of the non-trivial zeros of zeta are on a critical line in the complex plane, is one of the most important unsolved problems in modern mathematics. The present book consists of two parts. The first part covers classical material about the zeros of the Riemann zeta function with applications to the distribution of prime numbers, including those made by Riemann himself, F. Carlson, and Hardy-Littlewood. The second part gives a complete presentation of Levinson's method for zeros on the critical line, which allows one to prove, in particular, that more than one-third of non-trivial zeros of zeta are on the critical line. This approach and some results concerning integrals of Dirichlet polynomials are new. Th...

Zeta potential in colloid science principles and applications

CERN Document Server

Hunter, Robert J; Rowell, R L

2013-01-01

Zeta Potential in Colloid Science: Principles and Applications covers the concept of the zeta potential in colloid chemical theory. The book discusses the charge and potential distribution at interfaces; the calculation of the zeta potential; and the experimental techniques used in the measurement of electrokinetic parameters. The text also describes the electroviscous and viscoelectric effects; applications of the zeta potential to areas of colloid science; and the influence of simple inorganic ions or more complex adsorbates on zeta potential. Physical chemists and people involved in the stu

Lectures on zeta functions over finite fields

OpenAIRE

Wan, Daqing

2007-01-01

These are the notes from the summer school in G\\"ottingen sponsored by NATO Advanced Study Institute on Higher-Dimensional Geometry over Finite Fields that took place in 2007. The aim was to give a short introduction on zeta functions over finite fields, focusing on moment zeta functions and zeta functions of affine toric hypersurfaces.

Short-period AM CVn systems as optical, X-ray and gravitational-wave sources

NARCIS (Netherlands)

Nelemans, G.; Yungelson, L.; Portegies Zwart, S.F.

2004-01-01

We model the population of AM CVn systems in the Galaxy and discuss the detectability of these systems with optical, X-ray and gravitational-wave detectors. We concentrate on the short-period (P < 1500 s) systems, some of which are expected to be in a phase of direct-impact accretion. Using a

Discovery of a Detached, Eclipsing 40 Minute Period Double White Dwarf Binary and a Friend: Implications for He+CO White Dwarf Mergers

International Nuclear Information System (INIS)

Brown, Warren R.; Kilic, Mukremin; Kosakowski, Alekzander; Gianninas, A.

2017-01-01

We report the discovery of two detached double white dwarf (WD) binaries, SDSS J082239.546+304857.19 and SDSS J104336.275+055149.90, with orbital periods of 40 and 46 minutes, respectively. The 40 minute system is eclipsing; it is composed of a 0.30 M ⊙ and a 0.52 M ⊙ WD. The 46 minute system is a likely LISA verification binary. The short 20 ± 2 Myr and ∼34 Myr gravitational-wave merger times of the two binaries imply that many more such systems have formed and merged over the age of the Milky Way. We update the estimated Milky Way He+CO WD binary merger rate and affirm our previously published result: He+CO WD binaries merge at a rate at least 40 times greater than the formation rate of stable mass-transfer AM CVn binaries, and so the majority must have unstable mass-transfer. The implication is that spin–orbit coupling in He+CO WD mergers is weak, or perhaps nova-like outbursts drive He+CO WDs into merger, as proposed by Shen.

Discovery of a Detached, Eclipsing 40 Minute Period Double White Dwarf Binary and a Friend: Implications for He+CO White Dwarf Mergers

Energy Technology Data Exchange (ETDEWEB)

Brown, Warren R. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Kilic, Mukremin; Kosakowski, Alekzander; Gianninas, A., E-mail: wbrown@cfa.harvard.edu, E-mail: kilic@ou.edu, E-mail: alexg@nhn.ou.edu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks Street, Norman, OK 73019 (United States)

2017-09-20

We report the discovery of two detached double white dwarf (WD) binaries, SDSS J082239.546+304857.19 and SDSS J104336.275+055149.90, with orbital periods of 40 and 46 minutes, respectively. The 40 minute system is eclipsing; it is composed of a 0.30 M {sub ⊙} and a 0.52 M {sub ⊙} WD. The 46 minute system is a likely LISA verification binary. The short 20 ± 2 Myr and ∼34 Myr gravitational-wave merger times of the two binaries imply that many more such systems have formed and merged over the age of the Milky Way. We update the estimated Milky Way He+CO WD binary merger rate and affirm our previously published result: He+CO WD binaries merge at a rate at least 40 times greater than the formation rate of stable mass-transfer AM CVn binaries, and so the majority must have unstable mass-transfer. The implication is that spin–orbit coupling in He+CO WD mergers is weak, or perhaps nova-like outbursts drive He+CO WDs into merger, as proposed by Shen.

Surface characterization on binary nano/micro-domain composed of alkyl- and amino-terminated self-assembled monolayer

Energy Technology Data Exchange (ETDEWEB)

Lee, S.H. [Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553 (Japan); Ishizaki, T. [Materials Research Institute for Sustainable Development, National Institute of Advanced Industrial Science and Technology, 2266-98 Anagahora, Shimo-Shidami, Moriyama-ku, Nagoya 463-8560 (Japan); Saito, N. [Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagano 464-8603 (Japan)], E-mail: hiro@eco-t.esi.nagoya-u.ac.jp; Takai, O. [EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603 (Japan)

2008-09-15

The binary alkyl- and amino-terminated self-assembled monolayers (SAMs) composed of nano/micro-sized domains was prepared though a self-assembly technique. In addition, the wetting and electrostatic property of the binary SAMs was investigated by the analysis of the static and dynamic water contact angle and zeta-potentials measurement. The binary SAMs were also characterized by atomic force microscope (AFM), Kelvin probe force microscope (KPFM) and X-ray photoelectron spectroscopy (XPS). The domains on the binary SAMs were observed in topographic and surface potential images. The height of domain and the surface potential between octadecyltrichlorosilanes (OTS)-domain and n-(6-aminohexl)aminopropyl-trimethoxysilane (AHAPS)-SAM were about 1.1 nm and -30 mV. These differences of height and surface potential correspond to the ones between OTS and AHAPS. In XPS N 1s spectra, we confirmed the formation of binary SAMs by an amino peak observed at 399.15 eV. The dynamic and the static water contact angles indicated that the wetting property of the binary SAMs was depended on the OTS domain size. In addition, static water contact angles were measured under the conditions of different pH water and zeta-potential also indicated that the electrostatic property of the binary SAMs depended on OTS domain size. Thus, these results showed that the wetting and electrostatic property on the binary SAMs could be regulated by controlling the domain size.

Observational constraints on the inter-binary stellar flare hypothesis for the gamma-ray bursts

Science.gov (United States)

Rao, A. R.; Vahia, M. N.

1994-01-01

The Gamma Ray Observatory/Burst and Transient Source Experiment (GRO/BATSE) results on the Gamma Ray Bursts (GRBs) have given an internally consistent set of observations of about 260 GRBs which have been released for analysis by the BATSE team. Using this database we investigate our earlier suggestion (Vahia and Rao, 1988) that GRBs are inter-binary stellar flares from a group of objects classified as Magnetically Active Stellar Systems (MASS) which includes flare stars, RS CVn binaries and cataclysmic variables. We show that there exists an observationally consistent parameter space for the number density, scale height and flare luminosity of MASS which explains the complete log(N) - log(P) distribution of GRBs as also the observed isotropic distribution. We further use this model to predict anisotropy in the GRB distribution at intermediate luminosities. We make definite predictions under the stellar flare hypothesis that can be tested in the near future.

Use of Spectroscopic, Zeta Potential and Molecular Dynamic Techniques to Study the Interaction between Human Holo-Transferrin and Two Antagonist Drugs: Comparison of Binary and Ternary Systems

Directory of Open Access Journals (Sweden)

Mohammad Reza Saberi

2012-03-01

Full Text Available For the first time, the binding of ropinirole hydrochloride (ROP and aspirin (ASA to human holo-transferrin (hTf has been investigated by spectroscopic approaches (fluorescence quenching, synchronous fluorescence, time-resolved fluorescence, three-dimensional fluorescence, UV-vis absorption, circular dichroism, resonance light scattering, as well as zeta potential and molecular modeling techniques, under simulated physiological conditions. Fluorescence analysis was used to estimate the effect of the ROP and ASA drugs on the fluorescence of hTf as well as to define the binding and quenching properties of binary and ternary complexes. The synchronized fluorescence and three-dimensional fluorescence spectra demonstrated some micro-environmental and conformational changes around the Trp and Tyr residues with a faint red shift. Thermodynamic analysis displayed the van der Waals forces and hydrogen bonds interactions are the major acting forces in stabilizing the complexes. Steady-state and time-resolved fluorescence data revealed that the fluorescence quenching of complexes are static mechanism. The effect of the drugs aggregating on the hTf resulted in an enhancement of the resonance light scattering (RLS intensity. The average binding distance between were computed according to the forster non-radiation energy transfer theory. The circular dichroism (CD spectral examinations indicated that the binding of the drugs induced a conformational change of hTf. Measurements of the zeta potential indicated that the combination of electrostatic and hydrophobic interactions between ROP, ASA and hTf formed micelle-like clusters. The molecular modeling confirmed the experimental results. This study is expected to provide important insight into the interaction of hTf with ROP and ASA to use in various toxicological and therapeutic processes.

Zeta-potential and flotability of the scheelite mineral in different type of waters, Part 1: Zeta-potential

Directory of Open Access Journals (Sweden)

Milanović Dragan B.

2009-01-01

Full Text Available The aim of this work is the investigation of zeta-potential of the mineral scheelite from mine 'Rudnik', located in central Serbia. Electrophoresis measurements using zeta-meter were carried out on four different types of water, namely: tap water, distilled water, rain water and spring water. All types of water had different hardness and conductivity as well as natural pH values. It was found that the zeta-potential of mineral scheelite depends on the hardness and electro-conductivity of the chosen type of water as well as on Ca2+ content. The results obtained reveal the importance of proper choice of water as well as the type of reagents for flotation processes.

Bernoulli numbers and zeta functions

CERN Document Server

Arakawa, Tsuneo; Kaneko, Masanobu

2014-01-01

Two major subjects are treated in this book. The main one is the theory of Bernoulli numbers and the other is the theory of zeta functions. Historically, Bernoulli numbers were introduced to give formulas for the sums of powers of consecutive integers. The real reason that they are indispensable for number theory, however, lies in the fact that special values of the Riemann zeta function can be written by using Bernoulli numbers. This leads to more advanced topics, a number of which are treated in this book: Historical remarks on Bernoulli numbers and the formula for the sum of powers of consecutive integers; a formula for Bernoulli numbers by Stirling numbers; the Clausen–von Staudt theorem on the denominators of Bernoulli numbers; Kummer's congruence between Bernoulli numbers and a related theory of p-adic measures; the Euler–Maclaurin summation formula; the functional equation of the Riemann zeta function and the Dirichlet L functions, and their special values at suitable integers; various formulas of ...

Status of the zeta(8.3)

International Nuclear Information System (INIS)

Lowe, S.T.

1985-05-01

Results are presented from 22.1 pb -1 of UPSILON(1S) data, taken with the Crystal Ball detector at DORIS. These data were taken to further explore the zeta(8.3) signal originally seen in 10.4 pb -1 of UPSILON(1S) data. No evidence for the zeta is observed in this new sample. Data quality checks and possible explanations are discussed

Functional equation for the Mordell-Tornheim multiple zeta-function

OpenAIRE

Okamoto, Takuya; Onozuka, Tomokazu

2016-01-01

We show a relation between the Mordell-Tornheim multiple zeta-function and the confluent hypergeometric function, and using it, we give the functional equation for the Mordell-Tornheim multiple zeta-function. In the double case, the functional equation includes the known functional equation for the Euler-Zagier double zeta-function.

ACCURATE MASSES FOR THE PRIMARY AND SECONDARY IN THE ECLIPSING WHITE DWARF BINARY NLTT 11748

International Nuclear Information System (INIS)

Kilic, Mukremin; Brown, Warren R.; Kenyon, S. J.; Allende Prieto, Carlos; Agueeros, M. A.; Camilo, Fernando

2010-01-01

We measure the radial velocity curve of the eclipsing detached white dwarf binary NLTT 11748. The primary exhibits velocity variations with a semi-amplitude of 273 km s -1 and an orbital period of 5.641 hr. We do not detect any spectral features from the secondary star or any spectral changes during the secondary eclipse. We use our composite spectrum to constrain the temperature and surface gravity of the primary to be T eff = 8690 ± 140 K and log g = 6.54 ± 0.05, which correspond to a mass of 0.18 M sun . For an inclination angle of 89. 0 9 derived from the eclipse modeling, the mass function requires a 0.76 M sun companion. The merger time for the system is 7.2 Gyr. However, due to the extreme mass ratio of 0.24, the binary will most likely create an AM CVn system instead of a merger.

Mayer Transfer Operator Approach to Selberg Zeta Function

DEFF Research Database (Denmark)

Momeni, Arash; Venkov, Alexei

. In a special situation the dynamical zeta function is defined for a geodesic flow on a hyperbolic plane quotient by an arithmetic cofinite discrete group. More precisely, the flow is defined for the corresponding unit tangent bundle. It turns out that the Selberg zeta function for this group can be expressed...... in terms of a Fredholm determinant of a classical transfer operator of the flow. The transfer operator is defined in a certain space of holomorphic functions and its matrix representation in a natural basis is given in terms of the Riemann zeta function and the Euler gamma function....

Low-mass Pre-He White Dwarf Stars in Kepler Eclipsing Binaries with Multi-periodic Pulsations

Science.gov (United States)

Zhang, X. B.; Fu, J. N.; Liu, N.; Luo, C. Q.; Ren, A. B.

2017-12-01

We report the discovery of two thermally bloated low-mass pre-He white dwarfs (WDs) in two eclipsing binaries, KIC 10989032 and KIC 8087799. Based on the Kepler long-cadence photometry, we determined comprehensive photometric solutions of the two binary systems. The light curve analysis reveals that KIC 10989032 is a partially eclipsed detached binary system containing a probable low-mass WD with the temperature of about 10,300 K. Having a WD with the temperature of about 13,300, KKIC 8087799 is typical of an EL CVn system. By utilizing radial velocity measurements available for the A-type primary star of KIC 10989032, the mass and radius of the WD component are determined to be 0.24+/- 0.02 {M}⊙ and 0.50+/- 0.01 {R}⊙ , respectively. The values of mass and radius of the WD in KIC 8087799 are estimated as 0.16 ± 0.02 M ⊙ and 0.21 ± 0.01 R ⊙, respectively, according to the effective temperature and mean density of the A-type star derived from the photometric solution. We therefore introduce KIC 10989032 and KIC 8087799 as the eleventh and twelfth dA+WD eclipsing binaries in the Kepler field. Moreover, both binaries display marked multi-periodic pulsations superimposed on binary effects. A preliminary frequency analysis is applied to the light residuals when subtracting the synthetic eclipsing light curves from the observations, revealing that the light pulsations of the two systems are both due to the δ Sct-type primaries. We hence classify KIC 10989032 and KIC 8087799 as two WD+δ Sct binaries.

Introduction of an Elementary Method to Express $\\zeta(2n+1)$ in Terms of $\\zeta(2k)$ with $k\\geq 1$

OpenAIRE

Fujii, Kazuyuki; Suzuki, Tatsuo

2008-01-01

In this note we give the most elementary method (as far as we know) to express $\\zeta(2n+1)$ in terms of $\\{\\zeta(2k)|k\\geq 1\\}$. The method is based on only some elementary works by Leonhard Euler, so it is very instructive to non-experts or students.

Discovery of a Detached, Eclipsing 40 Minute Period Double White Dwarf Binary and a Friend: Implications for He+CO White Dwarf Mergers

Science.gov (United States)

Brown, Warren R.; Kilic, Mukremin; Kosakowski, Alekzander; Gianninas, A.

2017-09-01

We report the discovery of two detached double white dwarf (WD) binaries, SDSS J082239.546+304857.19 and SDSS J104336.275+055149.90, with orbital periods of 40 and 46 minutes, respectively. The 40 minute system is eclipsing; it is composed of a 0.30 M ⊙ and a 0.52 M ⊙ WD. The 46 minute system is a likely LISA verification binary. The short 20 ± 2 Myr and ˜34 Myr gravitational-wave merger times of the two binaries imply that many more such systems have formed and merged over the age of the Milky Way. We update the estimated Milky Way He+CO WD binary merger rate and affirm our previously published result: He+CO WD binaries merge at a rate at least 40 times greater than the formation rate of stable mass-transfer AM CVn binaries, and so the majority must have unstable mass-transfer. The implication is that spin-orbit coupling in He+CO WD mergers is weak, or perhaps nova-like outbursts drive He+CO WDs into merger, as proposed by Shen. Based on observations obtained at the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona, and on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium.

Tc Trends and Terrestrial Planet Formation: The Case of Zeta Reticuli

Science.gov (United States)

Adibekyan, Vardan; Delgado-Mena, Elisa; Figueira, Pedro; Sousa, Sergio; Santos, Nuno; Faria, Joao; González Hernández, Jonay; Israelian, Garik; Harutyunyan, Gohar; Suárez-Andrés, Lucia; Hakobyan, Artur

2016-11-01

During the last decade astronomers have been trying to search for chemical signatures of terrestrial planet formation in the atmospheres of the hosting stars. Several studies suggested that the chemical abundance trend with the condensation temperature, Tc, is a signature of rocky planet formation. In particular, it was suggested that the Sun shows 'peculiar' chemical abundances due to the presence of the terrestrial planets in our solar-system. However, the rocky material accretion or the trap of rocky materials in terrestrial planets is not the only explanation for the chemical 'peculiarity' of the Sun, or other Sun-like stars with planets. In this talk I madea very brief review of this topic, and presented our last results for the particular case of Zeta Reticuli binary system: A very interesting and well-known system (known in science fiction and ufology as the world of Grey Aliens, or Reticulans) where one of the components hosts an exo-Kuiper belt, and the other component is a 'single', 'lonely' star.

Influence of surface conductivity on the apparent zeta potential of calcite.

Science.gov (United States)

Li, Shuai; Leroy, Philippe; Heberling, Frank; Devau, Nicolas; Jougnot, Damien; Chiaberge, Christophe

2016-04-15

Zeta potential is a physicochemical parameter of particular importance in describing the surface electrical properties of charged porous media. However, the zeta potential of calcite is still poorly known because of the difficulty to interpret streaming potential experiments. The Helmholtz-Smoluchowski (HS) equation is widely used to estimate the apparent zeta potential from these experiments. However, this equation neglects the influence of surface conductivity on streaming potential. We present streaming potential and electrical conductivity measurements on a calcite powder in contact with an aqueous NaCl electrolyte. Our streaming potential model corrects the apparent zeta potential of calcite by accounting for the influence of surface conductivity and flow regime. We show that the HS equation seriously underestimates the zeta potential of calcite, particularly when the electrolyte is diluted (ionic strength ⩽ 0.01 M) because of calcite surface conductivity. The basic Stern model successfully predicted the corrected zeta potential by assuming that the zeta potential is located at the outer Helmholtz plane, i.e. without considering a stagnant diffuse layer at the calcite-water interface. The surface conductivity of calcite crystals was inferred from electrical conductivity measurements and computed using our basic Stern model. Surface conductivity was also successfully predicted by our surface complexation model. Copyright © 2016 Elsevier Inc. All rights reserved.

Radio-wavelength observations of magnetic fields on active dwarf-M, RS CVN and magnetic stars

Energy Technology Data Exchange (ETDEWEB)

Lang, K.R.

1986-01-01

The dwarf M stars YZ Canis Minoris and AD Leonis exhibit narrow band, slowly varying (hours) microwave emission that cannot be explained by conventional thermal radiation mechanisms. The dwarf M stars AD Leonis and Wolf 424 emit rapid spikes whose high brightness temperatures similarly require a nonthermal radiation process which could result from coherent mechanisms such as an electron-cyclotron maser or coherent-plasma radiation. If the electron-cyclotron maser emits at the second or third harmonic of the gyrofrequency, the coronal magnetic field strength H = 250 or 167 G and constraints on the plasma frequency imply an electron density of 6 x 10/sup 9//cm/sup 3/. Coherent-plasma radiation requires similar values of electron density but much weaker magnetic fields. Radio spikes from AD Leonis and Wolf 424 have rise times tau/sub R/ < 5 ms, indicating a linear size of L < 1.5 x 10/sup 8/ cm, or less than 0.005 of the stellar radius. Although Ap magnetic stars have strong dipole magnetic fields, they exhibit no detectable gyroresonant radiation, suggesting that these stars do not have hot, dense coronae. The binary RS CVn star UX Arietis exhibits variable emission at 6 cm wavelength on time scales ranging from 30 s to more than one hour. The shortest variation implies a linear size much less than that of the halo observed by VLBI techniques, and most probably sizes smaller than those of the component stars. The observed variations might be due to absorption by a thermal plasma located between the stars.

Heat kernels and zeta functions on fractals

International Nuclear Information System (INIS)

Dunne, Gerald V

2012-01-01

On fractals, spectral functions such as heat kernels and zeta functions exhibit novel features, very different from their behaviour on regular smooth manifolds, and these can have important physical consequences for both classical and quantum physics in systems having fractal properties. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical in honour of Stuart Dowker's 75th birthday devoted to ‘Applications of zeta functions and other spectral functions in mathematics and physics’. (paper)

Crossing the entropy barrier of dynamical zeta functions

International Nuclear Information System (INIS)

Aurich, R.; Bolte, J.; Matthies, C.; Sieber, M.; Steiner, F.

1992-01-01

Dynamical zeta functions are an important tool to quantize chaotic dynamical systems. The basic quantization rules require the computation of the zeta functions on the real energy axis, where the Euler product representations running over the classical periodic orbits usually do not converge due to the existence of the so-called entropy barrier determined by the topological entropy of the classical system. We shown that the convergence properties of the dynamical zeta functions rewritten as Dirichlet series are governed not only by the well-known topological and metric entropy, but depend crucially on subtle statistical properties of the Maslow indices and of the multiplicities of the periodic orbits that are measured by a new parameter for which we introduce the notion of a third entropy. If and only if the third entropy is nonvanishing, one can cross the entropy barrier; if it exceeds a certain value, one can even compute the zeta function in the physical region by means of a convergent Dirichlet series. A simple statistical model is presented which allows to compute the third entropy. Four examples of chaotic systems are studied in detail to test the model numerically. (orig.)

Crossing the entropy barrier of dynamical zeta functions

Energy Technology Data Exchange (ETDEWEB)

Aurich, R.; Bolte, J.; Matthies, C.; Sieber, M.; Steiner, F. (Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik)

1992-01-01

Dynamical zeta functions are an important tool to quantize chaotic dynamical systems. The basic quantization rules require the computation of the zeta functions on the real energy axis, where the Euler product representations running over the classical periodic orbits usually do not converge due to the existence of the so-called entropy barrier determined by the topological entropy of the classical system. We shown that the convergence properties of the dynamical zeta functions rewritten as Dirichlet series are governed not only by the well-known topological and metric entropy, but depend crucially on subtle statistical properties of the Maslow indices and of the multiplicities of the periodic orbits that are measured by a new parameter for which we introduce the notion of a third entropy. If and only if the third entropy is nonvanishing, one can cross the entropy barrier; if it exceeds a certain value, one can even compute the zeta function in the physical region by means of a convergent Dirichlet series. A simple statistical model is presented which allows to compute the third entropy. Four examples of chaotic systems are studied in detail to test the model numerically. (orig.).

Activation-induced proteolysis of cytoplasmic domain of zeta in T cell receptors and Fc receptors.

Science.gov (United States)

Taupin, J L; Anderson, P

1994-12-01

The CD3-T cell receptor (TCR) complex on T cells and the Fc gamma receptor type III (Fc gamma RIII)-zeta-gamma complex on natural killer cells are functionally analogous activation receptors that associate with a family of disulfide-linked dimers composed of the related subunits zeta and gamma. Immunochemical analysis of receptor complexes separated on two-dimensional diagonal gels allowed the identification of a previously uncharacterized zeta-p14 heterodimer. zeta-p14 is a component of both CD3-TCR and Fc gamma RIII-zeta-gamma. Peptide mapping analysis shows that p14 is structurally related to zeta, suggesting that it is either: (i) derived from zeta proteolytically or (ii) the product of an alternatively spliced mRNA. The observation that COS cells transformed with a cDNA encoding zeta express zeta-p14 supports the former possibility. The expression of CD3-TCR complexes including zeta-p14 increases following activation with phorbol 12-myristate 13-acetate or concanavalin A, suggesting that proteolysis of zeta may contribute to receptor modulation or desensitization.

Binary-induced magnetic activity?. Time-series echelle spectroscopy and photometry of HD 123351 = CZ CVn

Science.gov (United States)

Strassmeier, K. G.; Carroll, T. A.; Weber, M.; Granzer, T.; Bartus, J.; Oláh, K.; Rice, J. B.

2011-11-01

Context. Multi-wavelength time-series observations with high cadence and long duration are needed to resolve and understand the many variations of magnetically active late-type stars, which is an approach often used to observe the Sun. Aims: We present a first and detailed study of the bright and active K0IV-III star HD 123351. Methods: We acquired a total of 955 high-resolution STELLA echelle spectra during the years 2006-2010 and a total of 2260 photometric VIC data points during 1998-2010. These data are complemented by some spectra from CFHT and KPNO. Results: The star is found to be a single-lined spectroscopic binary with a period of 147.8919 ± 0.0003 days and a large eccentricity of e = 0.8086 ± 0.0001. The rms of the orbital solution is just 47 m s-1, making it the most precise orbit ever obtained for an active binary system. The rotation period is constrained from long-term photometry to be 58.32 ± 0.01 days. It shows that HD 123351 is a very asynchronous rotator, rotating five times slower than the expected pseudo-synchronous value. Two spotted regions persisted throughout the 12 years of our observations. We interpret them as active longitudes on a differentially rotating surface with a ΔP/P of 0.076. Four years of Hα, Ca ii H&K and He i D3 monitoring identifies the same main periodicity as the photometry but dynamic spectra also indicate that there is an intermittent dependence on the orbital period, in particular for Ca ii H&K in 2008. Line-profile inversions of a pair of Zeeman sensitive/insensitive iron lines yield an average surface magnetic-flux density of 542 ± 72 G. The time series for 2008 is modulated by the stellar rotation as well as the orbital motion, such that the magnetic flux is generally weaker during times of periastron and that the chromospheric emissions vary in anti-phase with the magnetic flux. We also identify a broad and asymmetric lithium line profile and measure an abundance of log n(Li) = 1.70 ± 0.05. The star

Absolute Properties of the Pulsating Post-mass Transfer Eclipsing Binary OO Draconis

Science.gov (United States)

Lee, Jae Woo; Hong, Kyeongsoo; Koo, Jae-Rim; Park, Jang-Ho

2018-01-01

OO Dra is a short-period Algol system with a δ Sct-like pulsator. We obtained time-series spectra between 2016 February and May to derive the fundamental parameters of the binary star and to study its evolutionary scenario. The radial velocity (RV) curves for both components were presented, and the effective temperature of the hotter and more massive primary was determined to be {T}{eff,1}=8260+/- 210 K by comparing the disentangling spectrum and the Kurucz models. Our RV measurements were solved with the BV light curves of Zhang et al. using the Wilson-Devinney binary code. The absolute dimensions of each component are determined as follows: M 1 = 2.03 ± 0.06 {M}⊙ , M 2 = 0.19 ± 0.01 {M}⊙ , R 1 = 2.08 ± 0.03 {R}⊙ , R 2 = 1.20 ± 0.02 {R}⊙ , L 1 = 18 ± 2 {L}⊙ , and L 2 = 2.0 ± 0.2 {L}⊙ . Comparison with stellar evolution models indicated that the primary star resides inside the δ Sct instability strip on the main sequence, while the cool secondary component is noticeably overluminous and oversized. We demonstrated that OO Dra is an oscillating post-mass transfer R CMa-type binary; the originally more massive star became the low-mass secondary component through mass loss caused by stellar wind and mass transfer, and the gainer became the pulsating primary as the result of mass accretion. The R CMa stars, such as OO Dra, are thought to have formed by non-conservative binary evolution and ultimately to evolve into EL CVn stars.

Zeta-potential of fouled thin film composite membrane

Energy Technology Data Exchange (ETDEWEB)

Ikeda, K.; Hachisuka, H.; Nakamura, T. [Nitto denko Corp., Ibaraki, (Japan); Kimura, S. [Kogakuin University, Tokyo (Japan). Dept. of Environ. Chemical Engineering; Ueyama, K. [Osaka University, Osaka (Japan). Dept. of Chemical Engineering

1999-10-01

The surface zeta-potential of a cross-linked polyamide thin film composite reverse osmosis membrane was measured using an electrophoresis method. It was confirmed that this method could be effectively applied to analyze the fouling of such membranes. It is known that the water flux of membranes drastically decreases as a result of fouling by surfactants. Although the surfactants adsorbed on reverse osmosis membranes could not be detected by conventional methods such as SEM, EDX and FT-IR, their presence could be clarified by the profile measurements of the surface zeta-potential. The profiles of the membrane surface zeta-potentials changed to more positive values in the measured pH range as a result of fouling by cationic or amphoteric surfactants. This measuring method of surface zeta-potentials allowed us to analyze a very small amount of fouling of a thin film composite reverse osmosis membrane. This method could be used to analyze the fouled surface of the thin film composite reverse osmosis membrane which is used for production of ultrapure water and shows a remarkable decrease in flux. It also became clear that this method is easy and effective for the reverse osmosis membrane surface analysis of adsorbed materials such as surfactants. (author)

Zeta potential of microfluidic substrates: 1. Theory, experimental techniques, and effects on separations.

Science.gov (United States)

Kirby, Brian J; Hasselbrink, Ernest F

2004-01-01

This paper summarizes theory, experimental techniques, and the reported data pertaining to the zeta potential of silica and silicon with attention to use as microfluidic substrate materials, particularly for microchip chemical separations. Dependence on cation concentration, buffer and cation type, pH, cation valency, and temperature are discussed. The Debye-Hückel limit, which is often correctly treated as a good approximation for describing the ion concentration in the double layer, can lead to serious errors if it is extended to predict the dependence of zeta potential on the counterion concentration. For indifferent univalent electrolytes (e.g., sodium and potassium), two simple scalings for the dependence of zeta potential on counterion concentration can be derived in high- and low-zeta limits of the nonlinear Poisson-Boltzman equation solution in the double layer. It is shown that for most situations relevant to microchip separations, the high-zeta limit is most applicable, leading to the conclusion that the zeta potential on silica substrates is approximately proportional to the logarithm of the molar counterion concentration. The zeta vs. pH dependence measurements from several experiments are compared by normalizing the zeta based on concentration.

Involvement of proteasomal subunits zeta and iota in RNA degradation.

Science.gov (United States)

Petit, F; Jarrousse, A S; Dahlmann, B; Sobek, A; Hendil, K B; Buri, J; Briand, Y; Schmid, H P

1997-01-01

We have identified two distinct subunits of 20 S proteasomes that are associated with RNase activity. Proteasome subunits zeta and iota, eluted from two-dimensional Western blots, hydrolysed tobacco mosaic virus RNA, whereas none of the other subunits degraded this substrate under the same conditions. Additionally, proteasomes were dissociated by 6 M urea, and subunit zeta, containing the highest RNase activity, was isolated by anion-exchange chromatography and gel filtration. Purified subunit zeta migrated as a single spot on two-dimensional PAGE with a molecular mass of approx. 28 kDa. Addition of anti-(subunit zeta) antibodies led to the co-precipitation of this proteasome subunit and nuclease activity. This is the first evidence that proteasomal alpha-type subunits are associated with an enzymic activity, and our results provide further evidence that proteasomes may be involved in cellular RNA metabolism. PMID:9337855

Instabilities of the zeta-function regularization in the presence of symmetries

International Nuclear Information System (INIS)

Rasetti, M.

1980-01-01

The zeta-function regularization method requires the calculation of the spectrum-generating function zeta sub(M) of a generic real, elliptic, self-adjoint differential operator on a manifold M. An asymptotic expansion for zeta sub(M) is given for the class of all symmetric spaces of rank 1, sufficient to compute its Mellin transform and deduce the regularization of the corresponding quadratic path integrals. The summability properties of the generalized zeta-function introduce physical instabilities in the system as negative specific heat. The technique (and the instability as well) is shown to hold - under the assumed symmetry properties - in any dimension (preserving both the global and local properties of the manifold, as opposed to the dimensional regularization, where one adds extra flat dimensions only). (author)

Probing the interaction of human serum albumin with vitamin B2 (riboflavin) and L-Arginine (L-Arg) using multi-spectroscopic, molecular modeling and zeta potential techniques

International Nuclear Information System (INIS)

Memarpoor-Yazdi, Mina; Mahaki, Hanie

2013-01-01

This study was designed to examine the interaction of Riboflavin (RB) and L-Arginine (L-Arg) with human serum albumin (HSA) using different spectroscopic, zeta potential and molecular modeling techniques under imitated physiological conditions. The resonance light scattering (RLS) method determined the critical aggregation concentration of RB on HSA in the presence and absence of L-Arg which confirmed the zeta potential results. The binding constants (K a ) of HSA–RB were 2.5×10 4 and 9.7×10 3 M −1 , respectively in binary and ternary system at the excitation wavelength of 280 nm, also were 7.5×10 3 and 7.3×10 3 , respectively in binary and ternary system at the excitation wavelength of 295 nm. Fluorescence spectroscopy demonstrated that in the presence of L-Arg, the binding constant of HSA–RB was increased. Static quenching was confirmed to results in the fluorescence quenching and FRET. The binding distances between HSA and RB in two- and three-component systems were estimated by the Forster theory which revealed that nonradiative energy transfer from HSA to RB occurred with a high probability. The effect of RB on the conformation of HSA was analyzed using synchronous fluorescence spectroscopy and circular dichroism (CD) in both systems. Docking studies demonstrated a reduction in the binding affinity between RB and HSA in the presence of L-Arg. -- Highlights: ► We studied the interaction of riboflavin with HSA in presence and absence of L-Arg. ► Molecular modeling and zeta-potential used to describe competitive interaction. ► We compared the binding mechanism of riboflavin (RB) to HSA in both systems. ► We determined critical aggregation concentration of RB on HSA in both systems. ► The binding site of RB on HSA in both systems has been determined

Probing the interaction of human serum albumin with vitamin B2 (riboflavin) and L-Arginine (L-Arg) using multi-spectroscopic, molecular modeling and zeta potential techniques

Energy Technology Data Exchange (ETDEWEB)

Memarpoor-Yazdi, Mina [Department of Biology, Faculty of Sciences, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Mahaki, Hanie, E-mail: hanieh.mahaki@gmail.com [Department of Biology, Faculty of Sciences, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of)

2013-04-15

This study was designed to examine the interaction of Riboflavin (RB) and L-Arginine (L-Arg) with human serum albumin (HSA) using different spectroscopic, zeta potential and molecular modeling techniques under imitated physiological conditions. The resonance light scattering (RLS) method determined the critical aggregation concentration of RB on HSA in the presence and absence of L-Arg which confirmed the zeta potential results. The binding constants (K{sub a}) of HSA–RB were 2.5×10{sup 4} and 9.7×10{sup 3} M{sup −1}, respectively in binary and ternary system at the excitation wavelength of 280 nm, also were 7.5×10{sup 3} and 7.3×10{sup 3}, respectively in binary and ternary system at the excitation wavelength of 295 nm. Fluorescence spectroscopy demonstrated that in the presence of L-Arg, the binding constant of HSA–RB was increased. Static quenching was confirmed to results in the fluorescence quenching and FRET. The binding distances between HSA and RB in two- and three-component systems were estimated by the Forster theory which revealed that nonradiative energy transfer from HSA to RB occurred with a high probability. The effect of RB on the conformation of HSA was analyzed using synchronous fluorescence spectroscopy and circular dichroism (CD) in both systems. Docking studies demonstrated a reduction in the binding affinity between RB and HSA in the presence of L-Arg. -- Highlights: ► We studied the interaction of riboflavin with HSA in presence and absence of L-Arg. ► Molecular modeling and zeta-potential used to describe competitive interaction. ► We compared the binding mechanism of riboflavin (RB) to HSA in both systems. ► We determined critical aggregation concentration of RB on HSA in both systems. ► The binding site of RB on HSA in both systems has been determined.

Dynamical zeta functions for piecewise monotone maps of the interval

CERN Document Server

Ruelle, David

2004-01-01

Consider a space M, a map f:M\\to M, and a function g:M \\to {\\mathbb C}. The formal power series \\zeta (z) = \\exp \\sum ^\\infty _{m=1} \\frac {z^m}{m} \\sum _{x \\in \\mathrm {Fix}\\,f^m} \\prod ^{m-1}_{k=0} g (f^kx) yields an example of a dynamical zeta function. Such functions have unexpected analytic properties and interesting relations to the theory of dynamical systems, statistical mechanics, and the spectral theory of certain operators (transfer operators). The first part of this monograph presents a general introduction to this subject. The second part is a detailed study of the zeta functions associated with piecewise monotone maps of the interval [0,1]. In particular, Ruelle gives a proof of a generalized form of the Baladi-Keller theorem relating the poles of \\zeta (z) and the eigenvalues of the transfer operator. He also proves a theorem expressing the largest eigenvalue of the transfer operator in terms of the ergodic properties of (M,f,g).

Oscillatory electroosmotic flow in a parallel-plate microchannel under asymmetric zeta potentials

Science.gov (United States)

Peralta, M.; Arcos, J.; Méndez, F.; Bautista, O.

2017-06-01

In this work, we conduct a theoretical analysis of the start-up of an oscillatory electroosmotic flow (EOF) in a parallel-plate microchannel under asymmetric zeta potentials. It is found that the transient evolution of the flow field is controlled by the parameters {R}ω , {R}\\zeta , and \\bar{κ }, which represent the dimensionless frequency, the ratio of the zeta potentials of the microchannel walls, and the electrokinetic parameter, which is defined as the ratio of the microchannel height to the Debye length. The analysis is performed for both low and high zeta potentials; in the former case, an analytical solution is derived, whereas in the latter, a numerical solution is obtained. These solutions provide the fundamental characteristics of the oscillatory EOFs for which, with suitable adjustment of the zeta potential and the dimensionless frequency, the velocity profiles of the fluid flow exhibit symmetric or asymmetric shapes.

Fractal diffusion coefficient from dynamical zeta functions

Energy Technology Data Exchange (ETDEWEB)

Cristadoro, Giampaolo [Max Planck Institute for the Physics of Complex Systems, Noethnitzer Str. 38, D 01187 Dresden (Germany)

2006-03-10

Dynamical zeta functions provide a powerful method to analyse low-dimensional dynamical systems when the underlying symbolic dynamics is under control. On the other hand, even simple one-dimensional maps can show an intricate structure of the grammar rules that may lead to a non-smooth dependence of global observables on parameters changes. A paradigmatic example is the fractal diffusion coefficient arising in a simple piecewise linear one-dimensional map of the real line. Using the Baladi-Ruelle generalization of the Milnor-Thurnston kneading determinant, we provide the exact dynamical zeta function for such a map and compute the diffusion coefficient from its smallest zero. (letter to the editor)

Fractal diffusion coefficient from dynamical zeta functions

International Nuclear Information System (INIS)

Cristadoro, Giampaolo

2006-01-01

Dynamical zeta functions provide a powerful method to analyse low-dimensional dynamical systems when the underlying symbolic dynamics is under control. On the other hand, even simple one-dimensional maps can show an intricate structure of the grammar rules that may lead to a non-smooth dependence of global observables on parameters changes. A paradigmatic example is the fractal diffusion coefficient arising in a simple piecewise linear one-dimensional map of the real line. Using the Baladi-Ruelle generalization of the Milnor-Thurnston kneading determinant, we provide the exact dynamical zeta function for such a map and compute the diffusion coefficient from its smallest zero. (letter to the editor)

Integrated module inverter using a zeta DC-DC converter with feedforward MPPT (Maximum Power Point Tracking) control; Inversor modulo integrado utilizando um conversor CC-CC zeta com controle MPPT feedforward

Energy Technology Data Exchange (ETDEWEB)

Lopez, Henrique Fioravanti Miguel

2009-08-15

This work presents the study and development of a processing power system that could be used in the connection of renewable energy sources to commercial power grid. The system consists of a ZETA converter associated with a bridge inverter operating at low frequency. The Zeta converter, operating in discontinuous conduction mode (DCM), plays the main role in this arrangement, producing a rectified sinusoidal current waveform synchronized with the electric grid. The function of the full-bridge inverter, connected in cascade with the Zeta converter, is to reverse every 180 deg the current generated by the Zeta converter. Initially it presents the analysis of the Zeta converter operating in DCM, as well as a design criterion. Following by the control strategy and the experimental results for the proposed system are presented and discussed. (author)

Zeta function methods and quantum fluctuations

International Nuclear Information System (INIS)

Elizalde, Emilio

2008-01-01

A review of some recent advances in zeta function techniques is given, in problems of pure mathematical nature but also as applied to the computation of quantum vacuum fluctuations in different field theories, and specially with a view to cosmological applications

On Montgomery's pair correlation conjecture to the zeros of Riedmann zeta function

OpenAIRE

Li, Pei

2005-01-01

In this thesis, we are interested in Montgomery's pair correlation conjecture which is about the distribution of.the spacings between consecutive zeros of the Riemann Zeta function. Our goal is to explain and study Montgomery's pair correlation conjecture and discuss its connection with the random matrix theory. In Chapter One, we will explain how to define the Ftiemann Zeta function by using the analytic continuation. After this, several classical properties of the Ftiemann Zeta function wil...

Chromospheric activity of periodic variable stars (including eclipsing binaries) observed in DR2 LAMOST stellar spectral survey

Science.gov (United States)

Zhang, Liyun; Lu, Hongpeng; Han, Xianming L.; Jiang, Linyan; Li, Zhongmu; Zhang, Yong; Hou, Yonghui; Wang, Yuefei; Cao, Zihuang

2018-05-01

The LAMOST spectral survey provides a rich databases for studying stellar spectroscopic properties and chromospheric activity. We cross-matched a total of 105,287 periodic variable stars from several photometric surveys and databases (CSS, LINEAR, Kepler, a recently updated eclipsing star catalogue, ASAS, NSVS, some part of SuperWASP survey, variable stars from the Tsinghua University-NAOC Transient Survey, and other objects from some new references) with four million stellar spectra published in the LAMOST data release 2 (DR2). We found 15,955 spectra for 11,469 stars (including 5398 eclipsing binaries). We calculated their equivalent widths (EWs) of their Hα, Hβ, Hγ, Hδ and Caii H lines. Using the Hα line EW, we found 447 spectra with emission above continuum for a total of 316 stars (178 eclipsing binaries). We identified 86 active stars (including 44 eclipsing binaries) with repeated LAMOST spectra. A total of 68 stars (including 34 eclipsing binaries) show chromospheric activity variability. We also found LAMOST spectra of 12 cataclysmic variables, five of which show chromospheric activity variability. We also made photometric follow-up studies of three short period targets (DY CVn, HAT-192-0001481, and LAMOST J164933.24+141255.0) using the Xinglong 60-cm telescope and the SARA 90-cm and 1-m telescopes, and obtained new BVRI CCD light curves. We analyzed these light curves and obtained orbital and starspot parameters. We detected the first flare event with a huge brightness increase of more than about 1.5 magnitudes in R filter in LAMOST J164933.24+141255.0.

On the $a$-points of the derivatives of the Riemann zeta function

OpenAIRE

Onozuka, Tomokazu

2016-01-01

We prove three results on the $a$-points of the derivatives of the Riemann zeta function. The first result is a formula of the Riemann-von Mangoldt type; we estimate the number of the $a$-points of the derivatives of the Riemann zeta function. The second result is on certain exponential sum involving $a$-points. The third result is an analogue of the zero density theorem. We count the $a$-points of the derivatives of the Riemann zeta function in $1/2-(\\log\\log T)^2/\\log T

Zeta function of self-adjoint operators on surfaces of revolution

International Nuclear Information System (INIS)

Lu, Tianshi; Jeffres, Thalia; Kirsten, Klaus

2015-01-01

In this article we analyze the zeta function for the Laplace operator on a surface of revolution. A variety of boundary conditions, separated and unseparated, are considered. Formulas for several residues and values of the zeta function as well as for the determinant of the Laplacian are obtained. The analysis is based upon contour integration techniques in combination with a WKB analysis of solutions of related initial value problems. (paper)

Lecture notes: string theory and zeta-function

Energy Technology Data Exchange (ETDEWEB)

Toppan, Francesco [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). E-mail: toppan@cbpf.br

2001-11-01

These lecture notes are based on a revised and LaTexed version of the Master thesis defended at ISAS. The research part being omitted, they included a review of the bosonic closed string a la Polyakov and of the one-loop background field method of quantisation defined through the zeta-function. In an appendix some basic features of the Riemann zeta-function are also reviewed. The pedagogical aspects of the material here presented are particularly emphasized. These notes are used, together with the Scherk's article in Rev. Mod. Phys. and the first volume of the Polchinski book, for the mini-course on String Theory (16-hours of lectures) held at CBPF. In this course the Green-Schwarz-Witten two-volumes book is also used for consultative purposes. (author)

Zeta functions for the spectrum of the non-commutative harmonic oscillators

CERN Document Server

Ichinose, T

2004-01-01

This paper investigates the spectral zeta function of the non-commutative harmonic oscillator studied in \\cite{PW1, 2}. It is shown, as one of the basic analytic properties, that the spectral zeta function is extended to a meromorphic function in the whole complex plane with a simple pole at $s=1$, and further that it has a zero at all non-positive even integers, i.e. at $s=0$ and at those negative even integers where the Riemann zeta function has the so-called trivial zeros. As a by-product of the study, both the upper and the lower bounds are also given for the first eigenvalue of the non-commutative harmonic oscillator.

BVRcIc OBSERVATIONS AND ANALYSES OF THE DWARF DETACHED BINARY V1043 CASSIOPEIA AND A COMMENT ON PRECONTACT W UMa'S

International Nuclear Information System (INIS)

Samec, R. G.; Smith, P. M.; Chamberlain, H.; Faulkner, D. R.; Van Hamme, W.

2013-01-01

Complete Bessel BVR c I c light curves of V1043 Cassiopeia [2MASS J00371195+5301324, Mis V1292, USNO–A2.0 1425–00875743, α(2000) = 00 h 37 m 11. s 95, δ(2000) = +53°01'32.''5] are analyzed. The system is a member of the small group of pre-contact W UMa binaries (PCWBs). Its light curve has the appearance of an Algol (EA) light curve, however it is made up of dwarf solar type components in a detached mode with a period of only 0.6616 days. The analysis includes a period study, an improved ephemeris, a mass ratio search, and a simultaneous BVR c I c Wilson-Devinney solution. We document about 20 other PCWBs given in the literature. Several have RS CVn-like properties.

Multiple zeta values and application to the Lacunary recurrence formulas of Bernoulli numbers

International Nuclear Information System (INIS)

Chen, Y-H

2008-01-01

This paper obtains a recurrence related to multiple zeta function, which generalizes the Newton recurrence for multiple zeta values for period 1. Moreover, we obtain some new Lacunary recurrence formulas of Bernoulli numbers

An induced current method for measuring zeta potential of electrolyte solution-air interface.

Science.gov (United States)

Song, Yongxin; Zhao, Kai; Wang, Junsheng; Wu, Xudong; Pan, Xinxiang; Sun, Yeqing; Li, Dongqing

2014-02-15

This paper reports a novel and very simple method for measuring the zeta potential of electrolyte solution-air interface. When a measuring electrode contacts the electrolyte solution-air interface, an electrical current will be generated due to the potential difference between the electrode-air surface and the electrolyte solution-air interface. The amplitude of the measured electric signal is linearly proportional to this potential difference; and depends only on the zeta potential at the electrolyte solution-air interface, regardless of the types and concentrations of the electrolyte. A correlation between the zeta potential and the measured voltage signal is obtained based on the experimental data. Using this equation, the zeta potential of any electrolyte solution-air interface can be evaluated quickly and easily by inserting an electrode through the electrolyte solution-air interface and measuring the electrical signal amplitude. This method was verified by comparing the obtained results of NaCl, MgCl2 and CaCl2 solutions of different pH values and concentrations with the zeta potential data reported in the published journal papers. Copyright © 2013 Elsevier Inc. All rights reserved.

Zeta functions and regularized determinants related to the Selberg trace formula

DEFF Research Database (Denmark)

Momeni, Arash; Venkov, Alexei

determinants of one dimensional Schroedinger operator for harmonic oscillator. We decompose the determinant of the automorphic Laplacian into a product of the determinants where each factor is a determinant representation of a zeta function related to Selberg's trace formula. Then we derive an identity...... connecting the determinants of the automorphic Laplacians on different Riemannian surfaces related to the arithmetical groups. Finally, by using the Jacquet-Langlands correspondence we connect the determinant of the automorphic Laplacian for the unit group of quaternions to the product of the determinants......For a general Fuchsian group of the first kind with an arbitrary unitary representation we define the zeta functions related to the contributions of the identity, hyperbolic, elliptic and parabolic conjugacy classes in Selberg's trace formula. We present Selberg's zeta function in terms...

Generalized Riemann zeta-function regularization and Casimir energy for a piecewise uniform string

International Nuclear Information System (INIS)

Li Xinzhou; Shi Xin; Zhang Jianzu.

1990-12-01

The generalized zeta-function techniques will be utilized to investigate the Casimir energy for the transverse oscillations of a piecewise uniform closed string. We find that zeta-function regularization method can lead straightforwardly to a correct result. (author). 6 refs

Interaction of nucleosome assembly proteins abolishes nuclear localization of DGK{zeta} by attenuating its association with importins

Energy Technology Data Exchange (ETDEWEB)

Okada, Masashi; Hozumi, Yasukazu [Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585 (Japan); Ichimura, Tohru [Department of Chemistry, Graduate School of Sciences and Engineering, Tokyo Metropolitan University, Hachioji 192-0397 (Japan); Tanaka, Toshiaki; Hasegawa, Hiroshi; Yamamoto, Masakazu; Takahashi, Nobuya [Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585 (Japan); Iseki, Ken [Department of Emergency and Critical Care Medicine, Yamagata University School of Medicine, Yamagata 990-9585 (Japan); Yagisawa, Hitoshi [Laboratory of Biological Signaling, Graduate School of Life Science, University of Hyogo, Hyogo 678-1297 (Japan); Shinkawa, Takashi; Isobe, Toshiaki [Department of Chemistry, Graduate School of Sciences and Engineering, Tokyo Metropolitan University, Hachioji 192-0397 (Japan); Goto, Kaoru, E-mail: kgoto@med.id.yamagata-u.ac.jp [Department of Anatomy and Cell Biology, Yamagata University School of Medicine, Yamagata 990-9585 (Japan)

2011-12-10

Diacylglycerol kinase (DGK) is involved in the regulation of lipid-mediated signal transduction through the metabolism of a second messenger diacylglycerol. Of the DGK family, DGK{zeta}, which contains a nuclear localization signal, localizes mainly to the nucleus but translocates to the cytoplasm under pathological conditions. However, the detailed mechanism of translocation and its functional significance remain unclear. To elucidate these issues, we used a proteomic approach to search for protein targets that interact with DGK{zeta}. Results show that nucleosome assembly protein (NAP) 1-like 1 (NAP1L1) and NAP1-like 4 (NAP1L4) are identified as novel DGK{zeta} binding partners. NAP1Ls constitutively shuttle between the nucleus and the cytoplasm in transfected HEK293 cells. The molecular interaction of DGK{zeta} and NAP1Ls prohibits nuclear import of DGK{zeta} because binding of NAP1Ls to DGK{zeta} blocks import carrier proteins, Qip1 and NPI1, to interact with DGK{zeta}, leading to cytoplasmic tethering of DGK{zeta}. In addition, overexpression of NAP1Ls exerts a protective effect against doxorubicin-induced cytotoxicity. These findings suggest that NAP1Ls are involved in a novel molecular basis for the regulation of nucleocytoplasmic shuttling of DGK{zeta} and provide a clue to examine functional significance of its translocation under pathological conditions.

Application of the zeta potential for stationary phase characterization in ion chromatography.

Science.gov (United States)

Buszewski, Bogusław; Jaćkowska, Magdalena; Bocian, Szymon; Dziubakiewicz, Ewelina

2013-01-01

Two series of homemade stationary bonded phases for ion chromatography were investigated according to their zeta potential. One set of dendrimer anion exchanger was synthesized on the polymer support whereas the second material was prepared on the silica gel. The zeta potential data in water environment as well as buffered water solution were obtained. The influence of the length of anion-exchanger chains, the type of the support of the modified surface, and charge distribution on these data was investigated. Additionally, the zeta potential was correlated with retention factor of inorganic ions to describe their influence on the retention mechanism in ion chromatography. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zeta Function Expression of Spin Partition Functions on Thermal AdS3

Directory of Open Access Journals (Sweden)

Floyd L.Williams

2015-07-01

Full Text Available We find a Selberg zeta function expression of certain one-loop spin partition functions on three-dimensional thermal anti-de Sitter space. Of particular interest is the partition function of higher spin fermionic particles. We also set up, in the presence of spin, a Patterson-type formula involving the logarithmic derivative of zeta.

77 FR 72975 - Zeta Cypermethrin; Pesticide Tolerances

Science.gov (United States)

2012-12-07

... for quantifying risks, there is no increase in hazard with increasing dosing duration. Therefore, the... exposure models in the dietary exposure analysis and risk assessment for zeta-cypermethrin in drinking... the dietary exposure model. For acute dietary risk assessment, the water concentration value of 3.77...

Bernoulli Polynomials, Fourier Series and Zeta Numbers

DEFF Research Database (Denmark)

Scheufens, Ernst E

2013-01-01

Fourier series for Bernoulli polynomials are used to obtain information about values of the Riemann zeta function for integer arguments greater than one. If the argument is even we recover the well-known exact values, if the argument is odd we find integral representations and rapidly convergent...

PTM Modeling of Dredged Suspended Sediment at Proposed Polaris Point and Ship Repair Facility CVN Berthing Sites - Apra Harbor, Guam

Science.gov (United States)

2017-09-01

sedimentation outside of the channel footprint. For example, dredging near the edge of the footprint can be confined to time periods when tidal currents...Cases 1 or 2 due to the lower loss rate. Sedimentation rates outside the channel prism are further reduced because all sediment is introduced in the...ER D C/ CH L TR -1 7- 16 PTM Modeling of Dredged Suspended Sediment at Proposed Polaris Point and Ship Repair Facility CVN Berthing

From Fourier Series to Rapidly Convergent Series for Zeta(3)

DEFF Research Database (Denmark)

Scheufens, Ernst E

2011-01-01

The article presents a mathematical study which investigates the exact values of the Riemann zeta (ζ) function. It states that exact values can be determined from Fourier series for periodic versions of even power functions. It notes that using power series for logarithmic functions on this such ......The article presents a mathematical study which investigates the exact values of the Riemann zeta (ζ) function. It states that exact values can be determined from Fourier series for periodic versions of even power functions. It notes that using power series for logarithmic functions...

Effective action for scalar fields and generalized zeta-function regularization

International Nuclear Information System (INIS)

Cognola, Guido; Zerbini, Sergio

2004-01-01

Motivated by the study of quantum fields in a Friedmann-Robertson-Walker space-time, the one-loop effective action for a scalar field defined in the ultrastatic manifold RxH 3 /Γ, H 3 /Γ being the finite volume, noncompact, hyperbolic spatial section, is investigated by a generalization of zeta-function regularization. It is shown that additional divergences may appear at the one-loop level. The one-loop renormalizability of the model is discussed and, making use of a generalization of zeta-function regularization, the one-loop renormalization group equations are derived

Euler Polynomials, Fourier Series and Zeta Numbers

DEFF Research Database (Denmark)

Scheufens, Ernst E

2012-01-01

Fourier series for Euler polynomials is used to obtain information about values of the Riemann zeta function for integer arguments greater than one. If the argument is even we recover the well-known exact values, if the argument is odd we find integral representations and rapidly convergent series....

Special values of the spectral zeta function of the non-commutative harmonic oscillator and confluent Heun equations

CERN Document Server

Ichinose, T

2004-01-01

We study the special values at $s=2$ and $3$ of the spectral zeta function $\\zeta_Q(s)$ of the non-commutative harmonic oscillator $Q(x,D_x)$ introduced in \\cite{PW1, 2}. It is shown that the series defining $\\zeta_Q(s)$ converges absolutely for Re $s>1$ and further the respective values $\\zeta_Q(2)$ and $\\zeta_Q(3)$ are represented essentially by contour integrals of the solutions, respectively, of a singly confluent Heun's ordinary differential equation and of exactly the same but an inhomogeneous equation. As a by-product of these results, we obtain integral representations of the solutions of these equations by rational functions. \\par\

New inequalities for the Hurwitz zeta function

Indian Academy of Sciences (India)

We establish various new inequalities for the Hurwitz zeta function. Our results generalize some known results ... mention here two of them: The first is the evaluation by Kolbig [10] of integrals of the form. Rm(μ, υ) = ∫ ∞. 0 e. −μttυ−1 log m t dt,.

Relating zeta functions of discrete and quantum graphs

Science.gov (United States)

Harrison, Jonathan; Weyand, Tracy

2018-02-01

We write the spectral zeta function of the Laplace operator on an equilateral metric graph in terms of the spectral zeta function of the normalized Laplace operator on the corresponding discrete graph. To do this, we apply a relation between the spectrum of the Laplacian on a discrete graph and that of the Laplacian on an equilateral metric graph. As a by-product, we determine how the multiplicity of eigenvalues of the quantum graph, that are also in the spectrum of the graph with Dirichlet conditions at the vertices, depends on the graph geometry. Finally we apply the result to calculate the vacuum energy and spectral determinant of a complete bipartite graph and compare our results with those for a star graph, a graph in which all vertices are connected to a central vertex by a single edge.

Zeros da função zeta de Riemann e o teorema dos números primos

OpenAIRE

Oliveira, Willian Diego [UNESP

2013-01-01

We studied various properties of the Riemann’s zeta function. Three proofs of the Prime Number Theorem were provides. Classical results on zero-free region of the zeta function, as well as their relation to the error term in the Prime Number Theorem, were studied in details Estudamos várias propriedades da função zeta de Riemann. Três provas do Teorema dos Números Primos foram fornecidas. Resultados clássicos sobre regiões livres de zeros da função zeta, bem como sua relação com o termo do...

Zeta-function approach to Casimir energy with singular potentials

International Nuclear Information System (INIS)

Khusnutdinov, Nail R.

2006-01-01

In the framework of zeta-function approach the Casimir energy for three simple model system: single delta potential, step function potential and three delta potentials are analyzed. It is shown that the energy contains contributions which are peculiar to the potentials. It is suggested to renormalize the energy using the condition that the energy of infinitely separated potentials is zero which corresponds to subtraction all terms of asymptotic expansion of zeta-function. The energy obtained in this way obeys all physically reasonable conditions. It is finite in the Dirichlet limit, and it may be attractive or repulsive depending on the strength of potential. The effective action is calculated, and it is shown that the surface contribution appears. The renormalization of the effective action is discussed

Wettability Studies Using Zeta Potential Measurements

Directory of Open Access Journals (Sweden)

Ghada Bassioni

2015-01-01

Full Text Available Wettability studies have been carried out on reservoir rocks using different techniques such as the Amott-Harvey method, the USBM method, and the contact angle method, all with limitations. In this study, the wettability is studied by discussing the surface charge using zeta potential measurements. The study relies on the finding that carbonated reservoir rocks, consisting of CaCO3 mainly, are positively charged and their surface has the potential to adsorb significant quantities of anions. Moreover, heavy fractions such as asphaltenes are reported to remain afloat depending on dispersive forces present in the oil and its various fractions. Experiments are carried out on aqueous limestone suspension with the addition of crude oil. The experiment is repeated with the use of polymeric inhibitors, A and B. The zeta potential is found to alter depending on the sequence of polymeric inhibitor in oil/water addition. The inhibitor is found to adsorb on the limestone surface, with a net negative charge, causing repulsion between crude oil and the inhibitor and, hence, preventing the deposition of heavy fractions and particularly asphaltenes. This study gives a comprehensive insight on the mechanism of polymeric inhibitor interaction with the surface and the effect of wettability on its performance.

Synthesis, bioactivity and zeta potential investigations of chlorine and fluorine substituted hydroxyapatite.

Science.gov (United States)

Fahami, Abbas; Beall, Gary W; Betancourt, Tania

2016-02-01

Chlorine and fluorine substituted hydroxyapatites (HA-Cl-F) with different degrees of ion replacement were successfully prepared by the one step mechanochemical activation method. X-ray diffraction (XRD) and FT-IR spectra indicated that substitution of these anions in milled powders resulted in the formation of pure hydroxyapatite phase except for the small observed change in the lattice parameters and unit cell volumes of the resultant hydroxyapatite. Microscopic observations showed that the milled product had a cluster-like structure made up of polygonal and spherical particles with an average particle size of approximately ranged from 20±5 to 70±5nm. The zeta potential of milled samples was performed at three different pH (5, 7.4, and 9). The obtained zeta potential values were negative for all three pH values. Negative zeta potential was described to favor osseointegration, apatite nucleation, and bone regeneration. The bioactivity of samples was investigated on sintered pellets soaked in simulated body fluid (SBF) solution and apatite crystals formed on the surface of the pellets after being incubated for 14days. Zeta potential analysis and bioactivity experiment suggested that HA-Cl-F will lead to the formation of new apatite particles and therefore be a potential implant material. Copyright © 2015 Elsevier B.V. All rights reserved.

The design and performance of ZETA

Energy Technology Data Exchange (ETDEWEB)

Butt, E P; Carruthers, R; Mitchell, J T.D.; Pease, R S; Thonemann, P C [U.K. Atomic Energy Authority, AERE Harwell (United Kingdom); Bird, M A; Blears, J; Hartill, E R [Metropolitan Vickers Electrical Co. Ltd., Trafiord Park, Manchester 17 (United Kingdom)

1958-07-01

ZETA is an experimental apparatus for studying the pinched ring discharge as a possible method of producing controlled thermonuclear power. The principle of this method is that the self-magnetic field of the discharge current isolates the plasma from the walls of the discharge tube. The present paper reports the principal mechanical and electrical parameters, the performance as an electrical circuit, and our present knowledge of the physical characteristics of the plasma.

On calculation of zeta function of integral matrix

Czech Academy of Sciences Publication Activity Database

Janáček, Jiří

2009-01-01

Roč. 134, č. 1 (2009), s. 49-58 ISSN 0862-7959 R&D Projects: GA AV ČR(CZ) IAA100110502 Institutional research plan: CEZ:AV0Z50110509 Keywords : Epstein zeta function * integral lattice * Riemann theta function Subject RIV: BA - General Mathematics

LONG-TERM EVOLUTION OF DOUBLE WHITE DWARF BINARIES ACCRETING THROUGH DIRECT IMPACT

International Nuclear Information System (INIS)

Kremer, Kyle; Kalogera, Vassiliki; Sepinsky, Jeremy

2015-01-01

We calculate the long-term evolution of angular momentum in double white dwarf binaries undergoing direct impact accretion over a broad range of parameter space. We allow the rotation rate of both components to vary and account for the exchange of angular momentum between the spins of the white dwarfs and the orbit, while conserving the total angular momentum. We include gravitational, tidal, and mass transfer effects in the orbital evolution, and allow the Roche radius of the donor star to vary with both the stellar mass and the rotation rate. We examine the long-term stability of these systems, focusing in particular on those systems that may be progenitors of AM CVn or SNe Ia. We find that our analysis yields an increase in the predicted number of stable systems compared to that in previous studies. Additionally, we find that by properly accounting for the effects of asynchronism between the donor and the orbit on the Roche-lobe size, we eliminate oscillations in the orbital parameters, which were found in previous studies. Removing these oscillations can reduce the peak mass transfer rate in some systems, keeping them from entering an unstable mass transfer phase

Zeta functional equation on Jordan algebras of type II

International Nuclear Information System (INIS)

Kayoya, J.B.

2003-10-01

Using the Jordan algebras method, specially the properties of Peirce decomposition and the Frobenius transformation, we compute the coefficients of the zeta functional equation, in the case of Jordan algebras of Type II. As particular cases of our result, we can cite the case of V M (n, R) studied by Gelbart and Godement-Jacquet, and the case of V Herm(3, O s ) studied by Muro. Let us also mention, that recently, Bopp and Rubenthaler have obtained a more general result on the zeta functional equation by using methods based on the algebraic properties of regular graded algebras which are in one to one correspondence with simple Jordan algebras. The method used in this paper is a direct application of specific properties of Jordan algebras of Type H. (author)

Surface Complexation Modeling of Calcite Zeta Potential Measurement in Mixed Brines for Carbonate Wettability Characterization

Science.gov (United States)

Song, J.; Zeng, Y.; Biswal, S. L.; Hirasaki, G. J.

2017-12-01

We presents zeta potential measurements and surface complexation modeling (SCM) of synthetic calcite in various conditions. The systematic zeta potential measurement and the proposed SCM provide insight into the role of four potential determining cations (Mg2+, SO42- , Ca2+ and CO32-) and CO2 partial pressure in calcite surface charge formation and facilitate the revealing of calcite wettability alteration induced by brines with designed ionic composition ("smart water"). Brines with varying potential determining ions (PDI) concentration in two different CO2 partial pressure (PCO2) are investigated in experiments. Then, a double layer SCM is developed to model the zeta potential measurements. Moreover, we propose a definition for contribution of charged surface species and quantitatively analyze the variation of charged species contribution when changing brine composition. After showing our model can accurately predict calcite zeta potential in brines containing mixed PDIs, we apply it to predict zeta potential in ultra-low and pressurized CO2 environments for potential applications in carbonate enhanced oil recovery including miscible CO2 flooding and CO2 sequestration in carbonate reservoirs. Model prediction reveals that pure calcite surface will be positively charged in all investigated brines in pressurized CO2 environment (>1atm). Moreover, the sensitivity of calcite zeta potential to CO2 partial pressure in the various brine is found to be in the sequence of Na2CO3 > Na2SO4 > NaCl > MgCl2 > CaCl2 (Ionic strength=0.1M).

Selberg zeta functions and transfer operators an experimental approach to singular perturbations

CERN Document Server

Fraczek, Markus Szymon

2017-01-01

This book presents a method for evaluating Selberg zeta functions via transfer operators for the full modular group and its congruence subgroups with characters. Studying zeros of Selberg zeta functions for character deformations allows us to access the discrete spectra and resonances of hyperbolic Laplacians under both singular and non-singular perturbations. Areas in which the theory has not yet been sufficiently developed, such as the spectral theory of transfer operators or the singular perturbation theory of hyperbolic Laplacians, will profit from the numerical experiments discussed in this book. Detailed descriptions of numerical approaches to the spectra and eigenfunctions of transfer operators and to computations of Selberg zeta functions will be of value to researchers active in analysis, while those researchers focusing more on numerical aspects will benefit from discussions of the analytic theory, in particular those concerning the transfer operator method and the spectral theory of hyperbolic spac...

Maximum mass ratio of am CVn-type binary systems and maximum white dwarf mass in ultra-compact x-ray binaries (addendum - Serb. Astron. J. No. 183 (2011, 63

Directory of Open Access Journals (Sweden)

Arbutina B.

2012-01-01

Full Text Available We recalculated the maximum white dwarf mass in ultra-compact X-ray binaries obtained in an earlier paper (Arbutina 2011, by taking the effects of super-Eddington accretion rate on the stability of mass transfer into account. It is found that, although the value formally remains the same (under the assumed approximations, for white dwarf masses M2 >~0.1MCh mass ratios are extremely low, implying that the result for Mmax is likely to have little if any practical relevance.

Potencial zeta de sulfatos de de bario y de estroncio

OpenAIRE

Delgado M., Edgar

2010-01-01

Por medio de la electroforesis se determinó las movilidades electroforéticas y los potenciales zeta del sulfato de bario a 25,0 °C como función de la fuerza iónica de NaCI, así como del Sulfato de estroncio en función de la fuerza iónica del cloruro de sodio y del pH. Se encontró que el amento de la fuerza iónica de NaCI causa un cambio del Potencial Zeta negativo del sulfato de estroncio a positivo con valor cero a aprox. 0,06 de fuerza iónica. El P.Z. del sulfato de estroncio es positivo...

Fractal zeta functions and fractal drums higher-dimensional theory of complex dimensions

CERN Document Server

Lapidus, Michel L; Žubrinić, Darko

2017-01-01

This monograph gives a state-of-the-art and accessible treatment of a new general higher-dimensional theory of complex dimensions, valid for arbitrary bounded subsets of Euclidean spaces, as well as for their natural generalization, relative fractal drums. It provides a significant extension of the existing theory of zeta functions for fractal strings to fractal sets and arbitrary bounded sets in Euclidean spaces of any dimension. Two new classes of fractal zeta functions are introduced, namely, the distance and tube zeta functions of bounded sets, and their key properties are investigated. The theory is developed step-by-step at a slow pace, and every step is well motivated by numerous examples, historical remarks and comments, relating the objects under investigation to other concepts. Special emphasis is placed on the study of complex dimensions of bounded sets and their connections with the notions of Minkowski content and Minkowski measurability, as well as on fractal tube formulas. It is shown for the f...

Gaussian basis sets for use in correlated molecular calculations. XI. Pseudopotential-based and all-electron relativistic basis sets for alkali metal (K-Fr) and alkaline earth (Ca-Ra) elements

Science.gov (United States)

Hill, J. Grant; Peterson, Kirk A.

2017-12-01

New correlation consistent basis sets based on pseudopotential (PP) Hamiltonians have been developed from double- to quintuple-zeta quality for the late alkali (K-Fr) and alkaline earth (Ca-Ra) metals. These are accompanied by new all-electron basis sets of double- to quadruple-zeta quality that have been contracted for use with both Douglas-Kroll-Hess (DKH) and eXact 2-Component (X2C) scalar relativistic Hamiltonians. Sets for valence correlation (ms), cc-pVnZ-PP and cc-pVnZ-(DK,DK3/X2C), in addition to outer-core correlation [valence + (m-1)sp], cc-p(w)CVnZ-PP and cc-pwCVnZ-(DK,DK3/X2C), are reported. The -PP sets have been developed for use with small-core PPs [I. S. Lim et al., J. Chem. Phys. 122, 104103 (2005) and I. S. Lim et al., J. Chem. Phys. 124, 034107 (2006)], while the all-electron sets utilized second-order DKH Hamiltonians for 4s and 5s elements and third-order DKH for 6s and 7s. The accuracy of the basis sets is assessed through benchmark calculations at the coupled-cluster level of theory for both atomic and molecular properties. Not surprisingly, it is found that outer-core correlation is vital for accurate calculation of the thermodynamic and spectroscopic properties of diatomic molecules containing these elements.

Gaussian basis sets for use in correlated molecular calculations. XI. Pseudopotential-based and all-electron relativistic basis sets for alkali metal (K-Fr) and alkaline earth (Ca-Ra) elements.

Science.gov (United States)

Hill, J Grant; Peterson, Kirk A

2017-12-28

New correlation consistent basis sets based on pseudopotential (PP) Hamiltonians have been developed from double- to quintuple-zeta quality for the late alkali (K-Fr) and alkaline earth (Ca-Ra) metals. These are accompanied by new all-electron basis sets of double- to quadruple-zeta quality that have been contracted for use with both Douglas-Kroll-Hess (DKH) and eXact 2-Component (X2C) scalar relativistic Hamiltonians. Sets for valence correlation (ms), cc-pVnZ-PP and cc-pVnZ-(DK,DK3/X2C), in addition to outer-core correlation [valence + (m-1)sp], cc-p(w)CVnZ-PP and cc-pwCVnZ-(DK,DK3/X2C), are reported. The -PP sets have been developed for use with small-core PPs [I. S. Lim et al., J. Chem. Phys. 122, 104103 (2005) and I. S. Lim et al., J. Chem. Phys. 124, 034107 (2006)], while the all-electron sets utilized second-order DKH Hamiltonians for 4s and 5s elements and third-order DKH for 6s and 7s. The accuracy of the basis sets is assessed through benchmark calculations at the coupled-cluster level of theory for both atomic and molecular properties. Not surprisingly, it is found that outer-core correlation is vital for accurate calculation of the thermodynamic and spectroscopic properties of diatomic molecules containing these elements.

Zeta potential of Polish copper-bearing shale in the absence and presence of flotation frothers

Directory of Open Access Journals (Sweden)

Mengsu Peng

2014-09-01

Full Text Available In this paper, zeta potential as a function of pH of copper-bearing shale, which is mined in Poland by KGHM, was investigated. The measurements were conducted in water and aqueous solutions of selected flotation frothers. It was established that for investigated copper-bearing shale, after dispersion in water, the isoelectric point (IEP occurs at pH=3.5. Addition of frothers decreased the IEP on the pH scale and the IEP for butanol was 1.93, for MIBC 2.90 and for eicosaethylene glycol hexadecyl ether (C16E20 2.76. In the case of introducing frothers changed, the zeta potential becomes less negative. An empirical equation, having two adjustable parameters, was used in the paper to approximate the course of the zeta potential-pH curve. The equation showed a very good approximation of the zeta potential of the investigated shale either in water or frother aqueous solutions.

Spectral zeta function and non-perturbative effects in ABJM Fermi-gas

International Nuclear Information System (INIS)

Hatsuda, Yasuyuki

2015-03-01

The exact partition function in ABJM theory on three-sphere can be regarded as a canonical partition function of a non-interacting Fermi-gas with an unconventional Hamiltonian. All the information on the partition function is encoded in the discrete spectrum of this Hamiltonian. We explain how (quantum mechanical) non-perturbative corrections in the Fermi-gas system appear from a spectral consideration. Basic tools in our analysis are a Mellin-Barnes type integral representation and a spectral zeta function. From a consistency with known results, we conjecture that the spectral zeta function in the ABJM Fermi-gas has an infinite number of ''non-perturbative'' poles, which are invisible in the semi-classical expansion of the Planck constant. We observe that these poles indeed appear after summing up perturbative corrections. As a consequence, the perturbative resummation of the spectral zeta function causes non-perturbative corrections to the grand canonical partition function. We also present another example associated with a spectral problem in topological string theory. A conjectured non-perturbative free energy on the resolved conifold is successfully reproduced in this framework.

LETTER TO THE EDITOR: Fractal diffusion coefficient from dynamical zeta functions

Science.gov (United States)

Cristadoro, Giampaolo

2006-03-01

Dynamical zeta functions provide a powerful method to analyse low-dimensional dynamical systems when the underlying symbolic dynamics is under control. On the other hand, even simple one-dimensional maps can show an intricate structure of the grammar rules that may lead to a non-smooth dependence of global observables on parameters changes. A paradigmatic example is the fractal diffusion coefficient arising in a simple piecewise linear one-dimensional map of the real line. Using the Baladi-Ruelle generalization of the Milnor-Thurnston kneading determinant, we provide the exact dynamical zeta function for such a map and compute the diffusion coefficient from its smallest zero.

Individual and binary toxicity of anatase and rutile nanoparticles towards Ceriodaphnia dubia

International Nuclear Information System (INIS)

Iswarya, V.; Bhuvaneshwari, M.; Chandrasekaran, N.; Mukherjee, Amitava

2016-01-01

Highlights: • Individual, binary toxicity of anatase and rutile NPs studied on Ceriodaphnia dubia. • Anatase and rutile phases showed differential effect upon variation in irradiation. • Mixture induced antagonistic at visible and additive effect at UV-A irradiation. • Marking-Dawson model fitted more appropriately than Abbott model. • Agglomeration played a major role in the toxicity induced by the mixture. - Abstract: Increasing usage of engineered nanoparticles, especially Titanium dioxide (TiO_2) in various commercial products has necessitated their toxicity evaluation and risk assessment, especially in the aquatic ecosystem. In the present study, a comprehensive toxicity assessment of anatase and rutile NPs (individual as well as a binary mixture) has been carried out in a freshwater matrix on Ceriodaphnia dubia under different irradiation conditions viz., visible and UV-A. Anatase and rutile NPs produced an LC_5_0 of about 37.04 and 48 mg/L, respectively, under visible irradiation. However, lesser LC_5_0 values of about 22.56 (anatase) and 23.76 (rutile) mg/L were noted under UV-A irradiation. A toxic unit (TU) approach was followed to determine the concentrations of binary mixtures of anatase and rutile. The binary mixture resulted in an antagonistic and additive effect under visible and UV-A irradiation, respectively. Among the two different modeling approaches used in the study, Marking-Dawson model was noted to be a more appropriate model than Abbott model for the toxicity evaluation of binary mixtures. The agglomeration of NPs played a significant role in the induction of antagonistic and additive effects by the mixture based on the irradiation applied. TEM and zeta potential analysis confirmed the surface interactions between anatase and rutile NPs in the mixture. Maximum uptake was noticed at 0.25 total TU of the binary mixture under visible irradiation and 1 TU of anatase NPs for UV-A irradiation. Individual NPs showed highest uptake under

Individual and binary toxicity of anatase and rutile nanoparticles towards Ceriodaphnia dubia

Energy Technology Data Exchange (ETDEWEB)

Iswarya, V.; Bhuvaneshwari, M.; Chandrasekaran, N.; Mukherjee, Amitava, E-mail: amit.mookerjea@gmail.com

2016-09-15

Highlights: • Individual, binary toxicity of anatase and rutile NPs studied on Ceriodaphnia dubia. • Anatase and rutile phases showed differential effect upon variation in irradiation. • Mixture induced antagonistic at visible and additive effect at UV-A irradiation. • Marking-Dawson model fitted more appropriately than Abbott model. • Agglomeration played a major role in the toxicity induced by the mixture. - Abstract: Increasing usage of engineered nanoparticles, especially Titanium dioxide (TiO{sub 2}) in various commercial products has necessitated their toxicity evaluation and risk assessment, especially in the aquatic ecosystem. In the present study, a comprehensive toxicity assessment of anatase and rutile NPs (individual as well as a binary mixture) has been carried out in a freshwater matrix on Ceriodaphnia dubia under different irradiation conditions viz., visible and UV-A. Anatase and rutile NPs produced an LC{sub 50} of about 37.04 and 48 mg/L, respectively, under visible irradiation. However, lesser LC{sub 50} values of about 22.56 (anatase) and 23.76 (rutile) mg/L were noted under UV-A irradiation. A toxic unit (TU) approach was followed to determine the concentrations of binary mixtures of anatase and rutile. The binary mixture resulted in an antagonistic and additive effect under visible and UV-A irradiation, respectively. Among the two different modeling approaches used in the study, Marking-Dawson model was noted to be a more appropriate model than Abbott model for the toxicity evaluation of binary mixtures. The agglomeration of NPs played a significant role in the induction of antagonistic and additive effects by the mixture based on the irradiation applied. TEM and zeta potential analysis confirmed the surface interactions between anatase and rutile NPs in the mixture. Maximum uptake was noticed at 0.25 total TU of the binary mixture under visible irradiation and 1 TU of anatase NPs for UV-A irradiation. Individual NPs showed highest

Note on asymptotic series expansions for the derivative of the Hurwitz zeta function and related functions

International Nuclear Information System (INIS)

Rudaz, S.

1990-01-01

Asymptotic series for the Hurwitz zeta function, its derivative, and related functions (including the Riemann zeta function of odd integer argument) are derived as an illustration of a simple, direct method of broad applicability, inspired by the calculus of finite differences

Synthesis, bioactivity and zeta potential investigations of chlorine and fluorine substituted hydroxyapatite

International Nuclear Information System (INIS)

Fahami, Abbas; Beall, Gary W.; Betancourt, Tania

2016-01-01

Chlorine and fluorine substituted hydroxyapatites (HA-Cl–F) with different degrees of ion replacement were successfully prepared by the one step mechanochemical activation method. X-ray diffraction (XRD) and FT-IR spectra indicated that substitution of these anions in milled powders resulted in the formation of pure hydroxyapatite phase except for the small observed change in the lattice parameters and unit cell volumes of the resultant hydroxyapatite. Microscopic observations showed that the milled product had a cluster-like structure made up of polygonal and spherical particles with an average particle size of approximately ranged from 20 ± 5 to 70 ± 5 nm. The zeta potential of milled samples was performed at three different pH (5, 7.4, and 9). The obtained zeta potential values were negative for all three pH values. Negative zeta potential was described to favor osseointegration, apatite nucleation, and bone regeneration. The bioactivity of samples was investigated on sintered pellets soaked in simulated body fluid (SBF) solution and apatite crystals formed on the surface of the pellets after being incubated for 14 days. Zeta potential analysis and bioactivity experiment suggested that HA-Cl–F will lead to the formation of new apatite particles and therefore be a potential implant material. - Highlights: • Cl"− and F"− substituted hydroxyapatite was synthesized by mechanochemical process. • Structural features were influenced strongly by incorporation of different ions. • Microscopic observations showed a mean particle size of around 20 ± 5 to 70 ± 5 nm. • The bioactivity properties indicated that apatite was successfully formed.

Synthesis, bioactivity and zeta potential investigations of chlorine and fluorine substituted hydroxyapatite

Energy Technology Data Exchange (ETDEWEB)

Fahami, Abbas, E-mail: fahami@txstate.edu [Materials Science, Engineering and Commercialization Program, Texas State University, San Marcos, TX 78666 (United States); Beall, Gary W. [Department of Chemistry and Biochemistry, Texas State University, 601 University Drive, San Marcos, TX 78666 (United States); Physics Department, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Betancourt, Tania [Materials Science, Engineering and Commercialization Program, Texas State University, San Marcos, TX 78666 (United States); Department of Chemistry and Biochemistry, Texas State University, 601 University Drive, San Marcos, TX 78666 (United States)

2016-02-01

Chlorine and fluorine substituted hydroxyapatites (HA-Cl–F) with different degrees of ion replacement were successfully prepared by the one step mechanochemical activation method. X-ray diffraction (XRD) and FT-IR spectra indicated that substitution of these anions in milled powders resulted in the formation of pure hydroxyapatite phase except for the small observed change in the lattice parameters and unit cell volumes of the resultant hydroxyapatite. Microscopic observations showed that the milled product had a cluster-like structure made up of polygonal and spherical particles with an average particle size of approximately ranged from 20 ± 5 to 70 ± 5 nm. The zeta potential of milled samples was performed at three different pH (5, 7.4, and 9). The obtained zeta potential values were negative for all three pH values. Negative zeta potential was described to favor osseointegration, apatite nucleation, and bone regeneration. The bioactivity of samples was investigated on sintered pellets soaked in simulated body fluid (SBF) solution and apatite crystals formed on the surface of the pellets after being incubated for 14 days. Zeta potential analysis and bioactivity experiment suggested that HA-Cl–F will lead to the formation of new apatite particles and therefore be a potential implant material. - Highlights: • Cl{sup −} and F{sup −} substituted hydroxyapatite was synthesized by mechanochemical process. • Structural features were influenced strongly by incorporation of different ions. • Microscopic observations showed a mean particle size of around 20 ± 5 to 70 ± 5 nm. • The bioactivity properties indicated that apatite was successfully formed.

A Comparison of Streaming and Microelectrophoresis Methods for Obtaining the zeta Potential of Granular Porous Media Surfaces.

Science.gov (United States)

Johnson

1999-01-01

The electrokinetic behavior of granular quartz sand in aqueous solution is investigated by both microelectrophoresis and streaming potential methods. zeta potentials of surfaces composed of granular quartz obtained via streaming potential methods are compared to electrophoretic mobility zeta potential values of colloid-sized quartz fragments. The zeta values generated by these alternate methods are in close agreement over a wide pH range and electrolyte concentrations spanning several orders of magnitude. Streaming measurements performed on chemically heterogeneous mixtures of physically homogeneous sand are shown to obey a simple mixing model based on the surface area-weighted average of the streaming potentials associated with the individual end members. These experimental results support the applicability of the streaming potential method as a means of determining the zeta potential of granular porous media surfaces. Copyright 1999 Academic Press.

Zeta Function Regularization in Casimir Effect Calculations and J. S. Dowker's Contribution

Science.gov (United States)

Elizalde, Emilio

2012-07-01

A summary of relevant contributions, ordered in time, to the subject of operator zeta functions and their application to physical issues is provided. The description ends with the seminal contributions of Stephen Hawking and Stuart Dowker and collaborators, considered by many authors as the actual starting point of the introduction of zeta function regularization methods in theoretical physics, in particular, for quantum vacuum fluctuation and Casimir effect calculations. After recalling a number of the strengths of this powerful and elegant method, some of its limitations are discussed. Finally, recent results of the so called operator regularization procedure are presented.

Probability laws related to the Jacobi theta and Riemann zeta function and Brownian excursions

OpenAIRE

Biane, P.; Pitman, J.; Yor, M.

1999-01-01

This paper reviews known results which connect Riemann's integral representations of his zeta function, involving Jacobi's theta function and its derivatives, to some particular probability laws governing sums of independent exponential variables. These laws are related to one-dimensional Brownian motion and to higher dimensional Bessel processes. We present some characterizations of these probability laws, and some approximations of Riemann's zeta function which are related to these laws.

Critical dimension of bosonic string theory and zeta-function regularization

International Nuclear Information System (INIS)

Vanzo, L.; Zerbini, S.; Istituto Nazionale di Fisica Nucleare, Povo

1988-01-01

A derivation of the critical dimension of the Polyakov bosonic string is presented. It is based on the use of the anholonomic formalism, a ghost-anti-ghost symmetric action, zeta-function regularization and the Seeley method of pseudo-differential operators. (orig.)

The Riemann zeta-function theory and applications

CERN Document Server

Ivic, Aleksandar

2003-01-01

""A thorough and easily accessible account.""-MathSciNet, Mathematical Reviews on the Web, American Mathematical Society. This extensive survey presents a comprehensive and coherent account of Riemann zeta-function theory and applications. Starting with elementary theory, it examines exponential integrals and exponential sums, the Voronoi summation formula, the approximate functional equation, the fourth power moment, the zero-free region, mean value estimates over short intervals, higher power moments, and omega results. Additional topics include zeros on the critical line, zero-density estim

Igusa's $p$-Adic local zeta function and the monodromy conjecture for non-degenerate surface singularities

CERN Document Server

Bories, Bart

2016-01-01

In 2011 Lemahieu and Van Proeyen proved the Monodromy Conjecture for the local topological zeta function of a non-degenerate surface singularity. The authors start from their work and obtain the same result for Igusa's p-adic and the motivic zeta function. In the p-adic case, this is, for a polynomial f\\in\\mathbf{Z}[x,y,z] satisfying f(0,0,0)=0 and non-degenerate with respect to its Newton polyhedron, we show that every pole of the local p-adic zeta function of f induces an eigenvalue of the local monodromy of f at some point of f^{-1}(0)\\subset\\mathbf{C}^3 close to the origin. Essentially the entire paper is dedicated to proving that, for f as above, certain candidate poles of Igusa's p-adic zeta function of f, arising from so-called B_1-facets of the Newton polyhedron of f, are actually not poles. This turns out to be much harder than in the topological setting. The combinatorial proof is preceded by a study of the integral points in three-dimensional fundamental parallelepipeds. Together with the work of L...

Swift observations of SDSS J141118.31+481257.6 during superoutburst

Science.gov (United States)

Rivera Sandoval, L. E.; Maccarone, T.

2018-06-01

We report on follow-up Swift observations of the AM CVn-type binary SDSS J141118.31+481257.6 (ATEL #11668, #11672). Based on ground based photometry, the re-brightening previous to the current superoutburst was reported on 2018-June-1 (https://www.aavso.org/aavso-alert-notice-636).

Chitosan-magnesium aluminum silicate composite dispersions: characterization of rheology, flocculate size and zeta potential.

Science.gov (United States)

Khunawattanakul, Wanwisa; Puttipipatkhachorn, Satit; Rades, Thomas; Pongjanyakul, Thaned

2008-03-03

Composite dispersions of chitosan (CS), a positively charged polymer, and magnesium aluminum silicate (MAS), a negatively charged clay, were prepared and rheology, flocculate size and zeta potential of the CS-MAS dispersions were investigated. High and low molecular weights of CS (HCS and LCS, respectively) were used in this study. Moreover, the effects of heat treatment at 60 degrees C on the characteristics of the CS-MAS dispersions and the zeta potential of MAS upon addition of CS at different pHs were examined. Incorporation of MAS into CS dispersions caused an increase in viscosity and a shift of CS flow type from Newtonian to pseudoplastic flow with thixotropic properties. Heat treatment brought about a significant decrease in viscosity and hysteresis area of the composite dispersions. Microscopic studies showed that flocculation of MAS occurred after mixing with CS. The size and polydispersity index of the HCS-MAS flocculate were greater than those of the LCS-MAS flocculate. However, a narrower size distribution and the smaller size of the HCS-MAS flocculate were found after heating at 60 degrees C. Zeta potentials of the CS-MAS flocculates were positive and slightly increased with increasing MAS content. In the zeta potential studies, the negative charge of the MAS could be neutralized by the addition of CS. Increasing the pH and molecular weight of CS resulted in higher CS concentrations required to neutralize the charge of MAS. These findings suggest that the electrostatic interaction between CS and MAS caused a change in flow behavior and flocculation of the composite dispersions, depending on the molecular weight of CS. Heat treatment affected the rheological properties and the flocculate size of the composite dispersions. Moreover, pH of medium and molecular weight of CS influence the zeta potential of MAS.

Influence of synthesis parameters on iron nanoparticle size and zeta potential

Science.gov (United States)

Goldstein, Nikki; Greenlee, Lauren F.

2012-03-01

Zero valent iron nanoparticles are of increasing interest in clean water treatment applications due to their reactivity toward organic contaminants and their potential to degrade a variety of compounds. This study focuses on the effect of organophosphate stabilizers on nanoparticle characteristics, including particle size distribution and zeta potential, when the stabilizer is present during nanoparticle synthesis. Particle size distributions from DLS were obtained as a function of stabilizer type and iron precursor (FeSO4·7H2O or FeCl3), and nanoparticles from 2 to 200 nm were produced. Three different organophosphate stabilizer compounds were compared in their ability to control nanoparticle size, and the size distributions obtained for particle volume demonstrated differences caused by the three stabilizers. A range of stabilizer-to-iron (0.05-0.9) and borohydride-to-iron (0.5-8) molar ratios were tested to determine the effect of concentration on nanoparticle size distribution and zeta potential. The combination of ferrous sulfate and ATMP or DTPMP phosphonate stabilizer produced stabilized nanoparticle suspensions, and the stabilizers tested resulted in varying particle size distributions. In general, higher stabilizer concentrations resulted in smaller nanoparticles, and excess borohydride did not decrease nanoparticle size. Zeta potential measurements were largely consistent with particle size distribution data and indicated the stability of the suspensions. Probe sonication, as a nanoparticle resuspension method, was minimally successful in several different organic solvents.

BVR{sub c}I{sub c} OBSERVATIONS AND ANALYSES OF THE DWARF DETACHED BINARY V1043 CASSIOPEIA AND A COMMENT ON PRECONTACT W UMa'S

Energy Technology Data Exchange (ETDEWEB)

Samec, R. G.; Smith, P. M.; Chamberlain, H. [Astronomy Group, Physics and Engineering Department, Bob Jones University, 1700 Wade Hampton Boulevard, Greenville, SC 29614 (United States); Faulkner, D. R. [Division of Math, Science, Nursing and Public Health, University of South Carolina, Lancaster, 476 Hubbard Drive, Lancaster, SC 29720 (United States); Van Hamme, W. [Physics Department, Florida International University, 11200 SW 8th Street, Miami, FL 33199 (United States)

2013-01-01

Complete Bessel BVR{sub c}I{sub c} light curves of V1043 Cassiopeia [2MASS J00371195+5301324, Mis V1292, USNO-A2.0 1425-00875743, {alpha}(2000) = 00{sup h}37{sup m}11.{sup s}95, {delta}(2000) = +53 Degree-Sign 01'32.''5] are analyzed. The system is a member of the small group of pre-contact W UMa binaries (PCWBs). Its light curve has the appearance of an Algol (EA) light curve, however it is made up of dwarf solar type components in a detached mode with a period of only 0.6616 days. The analysis includes a period study, an improved ephemeris, a mass ratio search, and a simultaneous BVR{sub c}I{sub c} Wilson-Devinney solution. We document about 20 other PCWBs given in the literature. Several have RS CVn-like properties.

In vitro phosphorylation of insulin receptor substrate 1 by protein kinase C-zeta: functional analysis and identification of novel phosphorylation sites.

Science.gov (United States)

Sommerfeld, Mark R; Metzger, Sabine; Stosik, Magdalene; Tennagels, Norbert; Eckel, Jürgen

2004-05-18

Protein kinase C-zeta (PKC-zeta) participates both in downstream insulin signaling and in the negative feedback control of insulin action. Here we used an in vitro approach to identify PKC-zeta phosphorylation sites within insulin receptor substrate 1 (IRS-1) and to characterize the functional implications. A recombinant IRS-1 fragment (rIRS-1(449)(-)(664)) containing major tyrosine motifs for interaction with phosphatidylinositol (PI) 3-kinase strongly associated to the p85alpha subunit of PI 3-kinase after Tyr phosphorylation by the insulin receptor. Phosphorylation of rIRS-1(449)(-)(664) by PKC-zeta induced a prominent inhibition of this process with a mixture of classical PKC isoforms being less effective. Both PKC-zeta and the classical isoforms phosphorylated rIRS-1(449)(-)(664) on Ser(612). However, modification of this residue did not reduce the affinity of p85alpha binding to pTyr-containing peptides (amino acids 605-615 of rat IRS-1), as determined by surface plasmon resonance. rIRS-1(449)(-)(664) was then phosphorylated by PKC-zeta using [(32)P]ATP and subjected to tryptic phosphopeptide mapping based on two-dimensional HPLC coupled to mass spectrometry. Ser(498) and Ser(570) were identified as novel phosphoserine sites targeted by PKC-zeta. Both sites were additionally confirmed by phosphopeptide mapping of the corresponding Ser --> Ala mutants of rIRS-1(449)(-)(664). Ser(570) was specifically targeted by PKC-zeta, as shown by immunoblotting with a phosphospecific antiserum against Ser(570) of IRS-1. Binding of p85alpha to the S570A mutant was less susceptible to inhibition by PKC-zeta, when compared to the S612A mutant. In conclusion, our in vitro data demonstrate a strong inhibitory action of PKC-zeta at the level of IRS-1/PI 3-kinase interaction involving multiple serine phosphorylation sites. Whereas Ser(612) appears not to participate in the negative control of insulin signaling, Ser(570) may at least partly contribute to this process.

Potencial zeta de sulfatos de de bario y de estroncio

Directory of Open Access Journals (Sweden)

Edgar Delgado M.

2010-06-01

Full Text Available Por medio de la electroforesis se determinó las movilidades electroforéticas y los potenciales zeta del sulfato de bario a 25,0 °C como función de la fuerza iónica de NaCI, así como del Sulfato de estroncio en función de la fuerza iónica del cloruro de sodio y del pH. Se encontró que el amento de la fuerza iónica de NaCI causa un cambio del Potencial Zeta negativo del sulfato de estroncio a positivo con valor cero a aprox. 0,06 de fuerza iónica. El P.Z. del sulfato de estroncio es positivo a pH inferiores a aprox. 2,5 y negativo a pH superiores. El sulfato de bario presenta P.Z. negativas a fuerza iónicas de NaCI inferiores a aprox. 0.06 y PZ positivos a fuerzas iónicas mayores

Influence of synthesis parameters on iron nanoparticle size and zeta potential

Energy Technology Data Exchange (ETDEWEB)

Goldstein, Nikki; Greenlee, Lauren F., E-mail: lauren.greenlee@nist.gov [National Institute of Standards and Technology, Materials Reliability Division (United States)

2012-03-15

Zero valent iron nanoparticles are of increasing interest in clean water treatment applications due to their reactivity toward organic contaminants and their potential to degrade a variety of compounds. This study focuses on the effect of organophosphate stabilizers on nanoparticle characteristics, including particle size distribution and zeta potential, when the stabilizer is present during nanoparticle synthesis. Particle size distributions from DLS were obtained as a function of stabilizer type and iron precursor (FeSO{sub 4}{center_dot}7H{sub 2}O or FeCl{sub 3}), and nanoparticles from 2 to 200 nm were produced. Three different organophosphate stabilizer compounds were compared in their ability to control nanoparticle size, and the size distributions obtained for particle volume demonstrated differences caused by the three stabilizers. A range of stabilizer-to-iron (0.05-0.9) and borohydride-to-iron (0.5-8) molar ratios were tested to determine the effect of concentration on nanoparticle size distribution and zeta potential. The combination of ferrous sulfate and ATMP or DTPMP phosphonate stabilizer produced stabilized nanoparticle suspensions, and the stabilizers tested resulted in varying particle size distributions. In general, higher stabilizer concentrations resulted in smaller nanoparticles, and excess borohydride did not decrease nanoparticle size. Zeta potential measurements were largely consistent with particle size distribution data and indicated the stability of the suspensions. Probe sonication, as a nanoparticle resuspension method, was minimally successful in several different organic solvents.

Influence of synthesis parameters on iron nanoparticle size and zeta potential

International Nuclear Information System (INIS)

Goldstein, Nikki; Greenlee, Lauren F.

2012-01-01

Zero valent iron nanoparticles are of increasing interest in clean water treatment applications due to their reactivity toward organic contaminants and their potential to degrade a variety of compounds. This study focuses on the effect of organophosphate stabilizers on nanoparticle characteristics, including particle size distribution and zeta potential, when the stabilizer is present during nanoparticle synthesis. Particle size distributions from DLS were obtained as a function of stabilizer type and iron precursor (FeSO 4 ·7H 2 O or FeCl 3 ), and nanoparticles from 2 to 200 nm were produced. Three different organophosphate stabilizer compounds were compared in their ability to control nanoparticle size, and the size distributions obtained for particle volume demonstrated differences caused by the three stabilizers. A range of stabilizer-to-iron (0.05–0.9) and borohydride-to-iron (0.5–8) molar ratios were tested to determine the effect of concentration on nanoparticle size distribution and zeta potential. The combination of ferrous sulfate and ATMP or DTPMP phosphonate stabilizer produced stabilized nanoparticle suspensions, and the stabilizers tested resulted in varying particle size distributions. In general, higher stabilizer concentrations resulted in smaller nanoparticles, and excess borohydride did not decrease nanoparticle size. Zeta potential measurements were largely consistent with particle size distribution data and indicated the stability of the suspensions. Probe sonication, as a nanoparticle resuspension method, was minimally successful in several different organic solvents.

Asymptotic analysis on a pseudo-Hermitian Riemann-zeta Hamiltonian

Science.gov (United States)

Bender, Carl M.; Brody, Dorje C.

2018-04-01

The differential-equation eigenvalue problem associated with a recently-introduced Hamiltonian, whose eigenvalues correspond to the zeros of the Riemann zeta function, is analyzed using Fourier and WKB analysis. The Fourier analysis leads to a challenging open problem concerning the formulation of the eigenvalue problem in the momentum space. The WKB analysis gives the exact asymptotic behavior of the eigenfunction.

"Armastuse retsepti" tippkokk Zeta Jones ei oska muna keeta / Triin Tael

Index Scriptorium Estoniae

Tael, Triin

2007-01-01

Scott Hicksi romantiline komöödiafilm "Armastuse retsept" ("No Reservations"), mille peaosas Walesist pärit näitlejanna Catherine Zeta Jones. Näitlejanna muljeid oma rolliks ettevalmistustest, mille hulka käis ka praktika pärisrestoranis

Fuzzy-PI-based centralised control of semi-isolated FP-SEPIC/ZETA BDC in a PV/battery hybrid system

Science.gov (United States)

Mahendran, Venmathi; Ramabadran, Ramaprabha

2016-11-01

Multiport converters with centralised controller have been most commonly used in stand-alone photovoltaic (PV)/battery hybrid system to supply the load smoothly without any disturbances. This study presents the performance analysis of four-port SEPIC/ZETA bidirectional converter (FP-SEPIC/ZETA BDC) using various types of centralised control schemes like Fuzzy tuned proportional integral controller (Fuzzy-PI), fuzzy logic controller (FLC) and conventional proportional integral (PI) controller. The proposed FP-SEPIC/ZETA BDC with various control strategy is derived for simultaneous power management of a PV source using distributed maximum power point tracking (DMPPT) algorithm, a rechargeable battery, and a load by means of centralised controller. The steady state and the dynamic response of the FP-SEPIC/ZETA BDC are analysed using three different types of controllers under line and load regulation. The Fuzzy-PI-based control scheme improves the dynamic response of the system when compared with the FLC and the conventional PI controller. The power balance between the ports is achieved by pseudorandom carrier modulation scheme. The response of the FP-SEPIC/ZETA BDC is also validated experimentally using hardware prototype model of 500 W system. The effectiveness of the control strategy is validated using simulation and experimental results.

Evaluation of spectral zeta-functions with the renormalization group

International Nuclear Information System (INIS)

Boettcher, Stefan; Li, Shanshan

2017-01-01

We evaluate spectral zeta-functions of certain network Laplacians that can be treated exactly with the renormalization group. As specific examples we consider a class of Hanoi networks and those hierarchical networks obtained by the Migdal–Kadanoff bond moving scheme from regular lattices. As possible applications of these results we mention quantum search algorithms as well as synchronization, which we discuss in more detail. (paper)

Tides in differentially rotating convective envelopes. II. The tidal coupling

International Nuclear Information System (INIS)

Scharlemann, E.T.

1982-01-01

The tidal coupling between a star with an extended, differentially rotating convective envelope, and its companion in a close binary system, is calculated from the tidal velocity field derived in Paper I. The derived coupling torque can be tested using observations of RS Canum Venaticorum systems, for which a photometric wave in the light curve provides an accurate stellar rotation rate, and for which observed orbital period changes require the stars in the systems to be coupled. The coupling torque is sufficient to explain the nearly synchronous rotation of the active star in RS CVn systems, despite the observed orbital period changes, but may not be able to explain the extreme tightness of the coupling implied by the very long periods for the migration of the photometric waves in the systems. This conclusion depends on the origin of the orbital period changes, but not on the nature of the wave or the wave migration. When the coupling torque vanishes, a specific latitude at the surface of the convective star will exactly corotate with the binary system: this corotation latitude is calculated. Finally, it is shown that the additional viscous terms introduced by tides should not suppress differential rotation in binary systems with RS Cvn parameters

Three aspects of stellar evolution near the main sequence

International Nuclear Information System (INIS)

Morgan, J.C.

1979-05-01

Three problems of stellar evolution are considered: the gap in the HR diagram of M67, the evolutionary status of RS CVn binaries and the solar neutrino problem. The physical basis of the Eggleton stellar evolution computer program is described. The program was used to calculate a grid of evolutionary tracks for models with masses between 0.7 and 1.29 solar masses. The more massive stars considered here have expanding convective cores during their main sequence evolution. The isochrone of the old galactic cluster M67 has a gap at the top of its main sequence because of the rapid evolution of stars at hydrogen exhaustion. RS CVn binaries present a complex collection of observational phenomena although they appear to be detached binaries. Their evolutionary status has remained controversial because of their high space density. Here it is shown that a post main sequence interpretation is satisfactory. Models of the Sun with metal poor interiors have been proposed in an attempt to resolve the solar neutrino problem. Here the evolution of two such models is calculated in detail, including a gradual contamination of the surface convection zone to produce the observed metal abundance, giving fully consistent models of the Sun as it is observed. (author)

Algorithms for Some Euler-Type Identities for Multiple Zeta Values

Directory of Open Access Journals (Sweden)

Shifeng Ding

2013-01-01

Full Text Available Multiple zeta values are the numbers defined by the convergent series ζ(s1,s2,…,sk=∑n1>n2>⋯>nk>0(1/n1s1 n2s2⋯nksk, where s1, s2, …, sk are positive integers with s1>1. For k≤n, let E(2n,k be the sum of all multiple zeta values with even arguments whose weight is 2n and whose depth is k. The well-known result E(2n,2=3ζ(2n/4 was extended to E(2n,3 and E(2n,4 by Z. Shen and T. Cai. Applying the theory of symmetric functions, Hoffman gave an explicit generating function for the numbers E(2n,k and then gave a direct formula for E(2n,k for arbitrary k≤n. In this paper we apply a technique introduced by Granville to present an algorithm to calculate E(2n,k and prove that the direct formula can also be deduced from Eisenstein's double product.

Non-Commutative Integration, Zeta Functions and the Haar State for SUq(2)

International Nuclear Information System (INIS)

Matassa, Marco

2015-01-01

We study a notion of non-commutative integration, in the spirit of modular spectral triples, for the quantum group SU q (2). In particular we define the non-commutative integral as the residue at the spectral dimension of a zeta function, which is constructed using a Dirac operator and a weight. We consider the Dirac operator introduced by Kaad and Senior and a family of weights depending on two parameters, which are related to the diagonal automorphisms of SU q (2). We show that, after fixing one of the parameters, the non-commutative integral coincides with the Haar state of SU q (2). Moreover we can impose an additional condition on the zeta function, which also fixes the second parameter. For this unique choice the spectral dimension coincides with the classical dimension

Averages of ratios of the Riemann zeta-function and correlations of divisor sums

Science.gov (United States)

Conrey, Brian; Keating, Jonathan P.

2017-10-01

Nonlinearity has published articles containing a significant number-theoretic component since the journal was first established. We examine one thread, concerning the statistics of the zeros of the Riemann zeta function. We extend this by establishing a connection between the ratios conjecture for the Riemann zeta-function and a conjecture concerning correlations of convolutions of Möbius and divisor functions. Specifically, we prove that the ratios conjecture and an arithmetic correlations conjecture imply the same result. This provides new support for the ratios conjecture, which previously had been motivated by analogy with formulae in random matrix theory and by a heuristic recipe. Our main theorem generalises a recent calculation pertaining to the special case of two-over-two ratios.

Interacting binaries

International Nuclear Information System (INIS)

Eggleton, P.P.; Pringle, J.E.

1985-01-01

This volume contains 15 review articles in the field of binary stars. The subjects reviewed span considerably, from the shortest period of interacting binaries to the longest, symbiotic stars. Also included are articles on Algols, X-ray binaries and Wolf-Rayet stars (single and binary). Contents: Preface. List of Participants. Activity of Contact Binary Systems. Wolf-Rayet Stars and Binarity. Symbiotic Stars. Massive X-ray Binaries. Stars that go Hump in the Night: The SU UMa Stars. Interacting Binaries - Summing Up

The True Ultracool Binary Fraction Using Spectral Binaries

Science.gov (United States)

Bardalez Gagliuffi, Daniella; Burgasser, Adam J.; Schmidt, Sarah J.; Gagné, Jonathan; Faherty, Jacqueline K.; Cruz, Kelle; Gelino, Chris

2018-01-01

Brown dwarfs bridge the gap between stars and giant planets. While the essential mechanisms governing their formation are not well constrained, binary statistics are a direct outcome of the formation process, and thus provide a means to test formation theories. Observational constraints on the brown dwarf binary fraction place it at 10 ‑ 20%, dominated by imaging studies (85% of systems) with the most common separation at 4 AU. This coincides with the resolution limit of state-of-the-art imaging techniques, suggesting that the binary fraction is underestimated. We have developed a separation-independent method to identify and characterize tightly-separated (dwarfs as spectral binaries by identifying traces of methane in the spectra of late-M and early-L dwarfs. Imaging follow-up of 17 spectral binaries yielded 3 (18%) resolved systems, corroborating the observed binary fraction, but 5 (29%) known binaries were missed, reinforcing the hypothesis that the short-separation systems are undercounted. In order to find the true binary fraction of brown dwarfs, we have compiled a volume-limited, spectroscopic sample of M7-L5 dwarfs and searched for T dwarf companions. In the 25 pc volume, 4 candidates were found, three of which are already confirmed, leading to a spectral binary fraction of 0.95 ± 0.50%, albeit for a specific combination of spectral types. To extract the true binary fraction and determine the biases of the spectral binary method, we have produced a binary population simulation based on different assumptions of the mass function, age distribution, evolutionary models and mass ratio distribution. Applying the correction fraction resulting from this method to the observed spectral binary fraction yields a true binary fraction of 27 ± 4%, which is roughly within 1σ of the binary fraction obtained from high resolution imaging studies, radial velocity and astrometric monitoring. This method can be extended to identify giant planet companions to young brown

High mobility group box-1 is phosphorylated by protein kinase C zeta and secreted in colon cancer cells

Energy Technology Data Exchange (ETDEWEB)

Lee, Hanna; Park, Minhee; Shin, Nara; Kim, Gamin [Department of Pathology, Yonsei University College of Medicine, 134 Shinchon-Dong, Seodaemoon-Ku, Seoul (Korea, Republic of); Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, 134 Shinchon-Dong, Seodaemoon-Ku, Seoul (Korea, Republic of); Kim, Yun Gi [Department of Internal Medicine, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-744 (Korea, Republic of); Shin, Jeon-Soo [Department of Microbiology, Yonsei University College of Medicine, 134 Shinchon-Dong, Seodaemoon-Ku, Seoul (Korea, Republic of); Kim, Hoguen, E-mail: hkyonsei@yuhs.ac [Department of Pathology, Yonsei University College of Medicine, 134 Shinchon-Dong, Seodaemoon-Ku, Seoul (Korea, Republic of); Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, 134 Shinchon-Dong, Seodaemoon-Ku, Seoul (Korea, Republic of)

2012-07-27

Highlights: Black-Right-Pointing-Pointer Specific enzyme for HMGB1 phosphorylation and its secretion is proposed. Black-Right-Pointing-Pointer Inhibition of PKC-{zeta} leads to significant reduction of the secreted HMGB1. Black-Right-Pointing-Pointer Phosphorylation of specific site of HMGB1 redirects its secretion in cancer cells. Black-Right-Pointing-Pointer Activation of PKC-{zeta} in cancers explains the enhanced HMGB1 secretion. -- Abstract: High mobility group box-1 (HMGB1), a nuclear protein, is overexpressed and secreted in cancer cells. Phosphorylation on two different nuclear localization signal regions are known to be important for the nuclear-to-cytoplasmic transport and secretion of HMGB1. However, little is known about the biochemical mechanism of HMGB1 modifications and its subsequent secretion from cancer cells. To identify the specific enzyme and important sites for HMGB1 phosphorylation, we screened the protein kinase C (PKC) family in a colon cancer cell line (HCT116) for HMGB1 binding by pull-down experiments using a 3XFLAG-HMGB1 construct. Strong interactions between atypical PKCs (PKC-{zeta}, {lambda}, and {iota}) and cytoplasmic HMGB1 were observed in HCT116 cells. We further identified the most critical PKC isotype that regulates HMGB1 secretion is PKC-{zeta} by using PKC inhibitors and siRNA experiments. The serine residues at S39, S53 and S181 of HMGB1 were related to enhancing HMGB1 secretion. We also demonstrated overexpression and activation of PKC-{zeta} in colon cancer tissues. Our findings suggest that PKC-{zeta} is involved in the phosphorylation of HMGB1, and the phosphorylation of specific serine residues in the nuclear localization signal regions is related to enhanced HMGB1 secretion in colon cancer cells.

Improving the Efficiency of a Coagulation-Flocculation Wastewater Treatment of the Semiconductor Industry through Zeta Potential Measurements

OpenAIRE

López-Maldonado, Eduardo Alberto; Oropeza-Guzmán, Mercedes Teresita; Ochoa-Terán, Adrián

2014-01-01

Efficiency of coagulation-flocculation process used for semiconductor wastewater treatment was improved by selecting suitable conditions (pH, polyelectrolyte type, and concentration) through zeta potential measurements. Under this scenario the zeta potential, ζ, is the right parameter that allows studying and predicting the interactions at the molecular level between the contaminants in the wastewater and polyelectrolytes used for coagulation-flocculation. Additionally, this parameter is a k...

On the issue of the {zeta} series convergence and loop corrections in the generation of observable primordial non-Gaussianity in slow-roll inflation: I. The bispectrum

Energy Technology Data Exchange (ETDEWEB)

Cogollo, Heiner R S; Rodriguez, Yeinzon; Valenzuela-Toledo, Cesar A, E-mail: heiner.sarmiento@ciencias.uis.edu.co, E-mail: yeinzon.rodriguez@uan.edu.co, E-mail: cavalto@ciencias.uis.edu.co [Escuela de Fisica, Universidad Industrial de Santander, Ciudad Universitaria, Bucaramanga (Colombia)

2008-08-15

We show in this paper that it is possible to attain very high, including observable, values for the level of non-Gaussianity f{sub NL} associated with the bispectrum B{sub {zeta}} of the primordial curvature perturbation {zeta}, in a subclass of small-field slow-roll models of inflation with canonical kinetic terms. Such a result is obtained by taking care of loop corrections both in the spectrum P{sub {zeta}} and in the bispectrum B{sub {zeta}}. Sizable values for f{sub NL} arise even if {zeta} is generated during inflation. Five issues are considered when constraining the available parameter space: (1) We must ensure that we are in a perturbative regime so that the {zeta} series expansion, and its truncation, are valid. (2) We must apply the correct condition for the (possible) loop dominance in B{sub {zeta}} and/or P{sub {zeta}}. (3) We must satisfy the spectrum normalization condition. (4) We must satisfy the spectral tilt constraint. (5) We must have enough inflation to solve the horizon problem.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

2016-01-27

Jan 27, 2016 ... Home; Journals; Journal of Astrophysics and Astronomy; Volume 26; Issue 4. Volume 26, Issue 4. December 2005, pages 359-456. pp 359-376. Unravelling the Nature of HD 81032 – A New RS CVn Binary · J. C. Pandey K. P. Singh S. A. Drake R. Sagar · More Details Abstract Fulltext PDF.

Zeta potentials of the rare earth element fluorcarbonate minerals focusing on bastnäsite and parisite.

Science.gov (United States)

Owens, C L; Nash, G R; Hadler, K; Fitzpatrick, R S; Anderson, C G; Wall, F

2018-06-01

Rare earth elements (REE) are critical to a wide range of technologies ranging from mobile phones to wind turbines. Processing and extraction of REE minerals from ore bodies is, however, both challenging and relatively poorly understood, as the majority of deposits contain only limited enrichment of REEs. An improved understanding of the surface properties of the minerals is important in informing and optimising their processing, in particular for separation by froth flotation. The measurement of zeta potential can be used to extract information regarding the electrical double layer, and hence surface properties of these minerals. There are over 34 REE fluorcarbonate minerals currently identified, however bastnäsite, synchysite and parisite are of most economic importance. Bastnäsite-(Ce), the most common REE fluorcarbonate, supplies over 50% of the world's REE. Previous studies of bastnäsite have showed a wide range of surface behaviour, with the iso-electric point (IEP), being measured between pH values of 4.6 and 9.3. In contrast, no values of IEP have been reported for parisite or synchysite. In this work, we review previous studies of the zeta potentials of bastnäsite to investigate the effects of different methodologies and sample preparation. In addition, measurements of zeta potentials of parisite under water, collector and supernatant conditions were conducted, the first to be reported. These results showed an iso-electric point for parisite of 5.6 under water, with a shift to a more negative zeta potential with both collector (hydroxamic and fatty acids) and supernatant conditions. The IEP with collectors and supernatant was <3.5. As zeta potential measurements in the presence of reagents and supernatants are the most rigorous way of determining the efficiency of a flotation reagent, the agreement between parisite zeta potentials obtained here and previous work on bastnäsite suggests that parisite may be processed using similar reagent schemes to

Hydrodynamic dispersion in a combined magnetohydrodynamic- electroosmotic-driven flow through a microchannel with slowly varying wall zeta potentials

Science.gov (United States)

Vargas, C.; Arcos, J.; Bautista, O.; Méndez, F.

2017-09-01

The effective dispersion coefficient of a neutral solute in the combined electroosmotic (EO) and magnetohydrodynamic (MHD)-driven flow of a Newtonian fluid through a parallel flat plate microchannel is studied. The walls of the microchannel are assumed to have modulated and low zeta potentials that vary slowly in the axial direction in a sinusoidal manner. The flow field required to obtain the dispersion coefficient is solved using the lubrication approximation theory. The solution of the electrical potential is based on the Debye-Hückel approximation for a symmetric (Z :Z ) electrolyte solution. The EO and MHD effects, together with the variations in the zeta potentials of the walls, are observed to notably modify the axial distribution of the effective dispersion coefficient. The problem is formulated for two cases of the zeta potential function. Note that the dispersion coefficient primarily depends on the Hartmann number, on the ratio of the half height of the microchannel to the Debye length, and on the assumed variation in the zeta potentials of the walls.

Zeta-function regularization of the quantum fluctuations around the Yang-Mills pseudoparticle

International Nuclear Information System (INIS)

Chadha, S.; Di Vecchia, P.; D'Adda, A.; Nicodemi, F.

1977-01-01

The hypersphere stereographic projection and the zeta-function regularization procedure are used to compute the one loop correction around the Yang-Mills pseudoparticle with scalars and fermions in an arbitrary representation of the SU(2) gauge group. (Auth.)

Ten physical applications of spectral zeta functions

CERN Document Server

Elizalde, Emilio

1995-01-01

Zeta-function regularization is a powerful method in perturbation theory. This book is meant as a guide for the student of this subject. Everything is explained in detail, in particular the mathematical difficulties and tricky points, and several applications are given to show how the procedure works in practice (e.g. Casimir effect, gravity and string theory, high-temperature phase transition, topological symmetry breaking). The formulas some of which are new can be used for accurate numerical calculations. The book is to be considered as a basic introduction and a collection of exercises for those who want to apply this regularization procedure in practice.

The multiple zeta value data mine

Energy Technology Data Exchange (ETDEWEB)

Buemlein, J. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Broadhurst, D.J. [Open Univ., Milton Keynes (United Kingdom). Physics and Astronomy Dept.; Vermaseren, J.A.M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); NIKHEF, Amsterdam (Netherlands)

2009-07-15

We provide a data mine of proven results for multiple zeta values (MZVs) of the form {zeta}(s{sub 1},s{sub 2},..,s{sub k}) = sum {sup {infinity}}{sub n{sub 1}}{sub >n{sub 2}}{sub >...>n{sub k}}{sub >0} {l_brace}1/(n{sub 1}{sup s{sub 1}}..n{sub k}{sup s{sub k}}){r_brace} with weight w = sum {sup K}{sub i=1}s{sub i} and depth k and for Euler sums of the form sum {sup {infinity}}{sub n{sub 1}}{sub >n{sub 2}}{sub >...>n{sub k}}{sub >0} {l_brace}({epsilon}{sub 1}{sup n{sub 1}}..{epsilon}{sub 1}{sup n{sub k}})/(n{sub 1}{sup s{sub 1}}..n{sub k}{sup s{sub k}}){r_brace} with signs {epsilon}{sub i} = {+-} 1. Notably, we achieve explicit proven reductions of all MZVs with weights w{<=}22, and all Euler sums with weights w{<=}12, to bases whose dimensions, bigraded by weight and depth, have sizes in precise agreement with the Broadhurst. Kreimer and Broadhurst conjectures. Moreover, we lend further support to these conjectures by studying even greater weights (w{<=}30), using modular arithmetic. To obtain these results we derive a new type of relation for Euler sums, the Generalized Doubling Relations. We elucidate the ''pushdown'' mechanism, whereby the ornate enumeration of primitive MZVs, by weight and depth, is reconciled with the far simpler enumeration of primitive Euler sums. There is some evidence that this pushdown mechanism finds its origin in doubling relations. We hope that our data mine, obtained by exploiting the unique power of the computer algebra language FORM, will enable the study of many more such consequences of the double-shuffle algebra of MZVs, and their Euler cousins, which are already the subject of keen interest, to practitioners of quantum field theory, and to mathematicians alike. (orig.)

Hydrogen exchange rate of tyrosine hydroxyl groups in proteins as studied by the deuterium isotope effect on C(zeta) chemical shifts.

Science.gov (United States)

Takeda, Mitsuhiro; Jee, Jungoo; Ono, Akira Mei; Terauchi, Tsutomu; Kainosho, Masatsune

2009-12-30

We describe a new NMR method for monitoring the individual hydrogen exchange rates of the hydroxyl groups of tyrosine (Tyr) residues in proteins. The method utilizes (2S,3R)-[beta(2),epsilon(1,2)-(2)H(3);0,alpha,beta,zeta-(13)C(4);(15)N]-Tyr, zeta-SAIL Tyr, to detect and assign the (13)C(zeta) signals of Tyr rings efficiently, either by indirect (1)H-detection through 7-8 Hz (1)H(delta)-(13)C(zeta) spin couplings or by direct (13)C(zeta) observation. A comparison of the (13)C(zeta) chemical shifts of three Tyr residues of an 18.2 kDa protein, EPPIb, dissolved in H(2)O and D(2)O, revealed that all three (13)C(zeta) signals in D(2)O appeared at approximately 0.13 ppm ( approximately 20 Hz at 150.9 MHz) higher than those in H(2)O. In a H(2)O/D(2)O (1:1) mixture, however, one of the three signals for (13)C(zeta) appeared as a single peak at the averaged chemical shifts, and the other two appeared as double peaks at exactly the same chemical shifts in H(2)O and D(2)O, in 50 mM phosphate buffer (pH 6.6) at 40 degrees C. These three peaks were assigned to Tyr-36, Tyr-120, and Tyr-30, from the lower to higher chemical shifts, respectively. The results indicate that the hydroxyl proton of Tyr-120 exchanges faster than a few milliseconds, whereas those of Tyr-30 and Tyr-36 exchange more slowly. The exchange rate of the Tyr-30 hydroxyl proton, k(ex), under these conditions was determined by (13)C NMR exchange spectroscopy (EXSY) to be 9.2 +/- 1.1 s(-1). The Tyr-36 hydroxyl proton, however, exchanges too slowly to be determined by EXSY. These profound differences among the hydroxyl proton exchange rates are closely related to their relative solvent accessibility and the hydrogen bonds associated with the Tyr hydroxyl groups in proteins.

Learning to assign binary weights to binary descriptor

Science.gov (United States)

Huang, Zhoudi; Wei, Zhenzhong; Zhang, Guangjun

2016-10-01

Constructing robust binary local feature descriptors are receiving increasing interest due to their binary nature, which can enable fast processing while requiring significantly less memory than their floating-point competitors. To bridge the performance gap between the binary and floating-point descriptors without increasing the computational cost of computing and matching, optimal binary weights are learning to assign to binary descriptor for considering each bit might contribute differently to the distinctiveness and robustness. Technically, a large-scale regularized optimization method is applied to learn float weights for each bit of the binary descriptor. Furthermore, binary approximation for the float weights is performed by utilizing an efficient alternatively greedy strategy, which can significantly improve the discriminative power while preserve fast matching advantage. Extensive experimental results on two challenging datasets (Brown dataset and Oxford dataset) demonstrate the effectiveness and efficiency of the proposed method.

Surface and zeta-potentials of silver halide single crystals: pH-dependence in comparison to particle systems

International Nuclear Information System (INIS)

Selmani, Atiða; Kallay, Nikola; Preočanin, Tajana; Lützenkirchen, Johannes

2014-01-01

We have carried out surface and zeta-potential measurements on AgCl and AgBr single crystals. As for particle systems we find that, surprisingly and previously unnoted, the zeta-potential exhibits pH-dependence, while the surface potential does not. A possible interpretation of these observations is the involvement of water ions in the interfacial equilibria and in particular, stronger affinity of the hydroxide ion compared to the proton. The pH-dependence of the zeta-potential can be suppressed at sufficiently high silver concentrations, which agrees with previous measurements in particle systems where no pH-dependence was found at high halide ion concentrations. The results suggest a subtle interplay between the surface potential determining the halide and silver ion concentrations, and the water ions. Whenever the charge due to the halide and silver ions is sufficiently high, the influence of the proton/hydroxide ion on the zeta-potential vanishes. This might be related to the water structuring at the relevant interfaces which should be strongly affected by the surface potential. Another interesting observation is accentuation of the assumed water ion effect on the zeta-potential at the flat single crystal surfaces compared to the corresponding silver halide colloids. Previous generic MD simulations have indeed predicted that hydroxide ion adsorption is accentuated on flat/rigid surfaces. A thermodynamic model for AgI single crystals was developed to describe the combined effects of iodide, silver and water ions, based on two independently previously published models for AgI (that only consider constituent and background electrolyte ions) and inert surfaces (that only consider water and background electrolyte ions). The combined model correctly predicts all the experimentally observed trends. (paper)

Effect of Zeta Potential on the Properties of Nano-Drug Delivery ...

African Journals Online (AJOL)

Zeta potential is a scientific term for electrokinetic potential in colloidal systems which has a major effect on the various properties of nano-drug delivery systems. Presently, colloidal nano-carriers are growing at a remarkable rate owing to their strong potential for overcoming old challenges such as poor drug solubility and ...

Masking of the CD3 gamma di-leucine-based motif by zeta is required for efficient T-cell receptor expression

DEFF Research Database (Denmark)

Lauritsen, Jens Peter H; Bonefeld, Charlotte Menné; von Essen, Marina

2004-01-01

containing the di-leucine-based endocytosis motif of the TCR subunit CD3 gamma have indicated that the zeta chain can mask this motif. In this study, we show that successive truncations of the cytoplasmic tail of zeta led to reduced surface expression levels of completely assembled TCR complexes. The reduced...... TCR expression levels were caused by an increase in the TCR endocytic rate constant in combination with an unaffected exocytic rate constant. Furthermore, the TCR degradation rate constant was increased in cells with truncated zeta. Introduction of a CD3 gamma chain with a disrupted di-leucine...

A zeta function approach to the semiclassical quantization of maps

International Nuclear Information System (INIS)

Smilansky, Uzi.

1993-11-01

The quantum analogue of an area preserving map on a compact phase space is a unitary (evolution) operator which can be represented by a matrix of dimension L∝ℎ -1 . The semiclassical theory for spectrum of the evolution operator will be reviewed with special emphasize on developing a dynamical zeta function approach, similar to the one introduced recently for a semiclassical quantization of hamiltonian systems. (author)

Binary Linear-Time Erasure Decoding for Non-Binary LDPC codes

OpenAIRE

Savin, Valentin

2009-01-01

In this paper, we first introduce the extended binary representation of non-binary codes, which corresponds to a covering graph of the bipartite graph associated with the non-binary code. Then we show that non-binary codewords correspond to binary codewords of the extended representation that further satisfy some simplex-constraint: that is, bits lying over the same symbol-node of the non-binary graph must form a codeword of a simplex code. Applied to the binary erasure channel, this descript...

Measuring the zeta potential. The relationships with sandstone fineness

Directory of Open Access Journals (Sweden)

de Luxán, M. P.

1989-09-01

Full Text Available The application of the zeta potential technique in the area of construction materials and Portland cement is quite recent. The initial research work involved the study of cement suspensions or suspensions of one of the components of cement, such as alite, tricalcium alumínate, in the presence of additives and, more specifically, superplasticizers. The studies of this sort were extended with the mixing of active additions into cement (fly ashes, etc.. The present study discusses the application of siliceous materials (sandstone as a basis of the research into the behaviour of sandstone mortars containing repair products.

La aplicación de la técnica del potencial zeta en el campo de los materiales de construcción y del cemento portland es muy reciente. Las primeras investigaciones se refieren al estudio de suspensiones de cemento o de alguno de sus compuestos que lo forman como alita, aluminato tricálcico, en presencia de aditivos y, más concretamente, de superfluidificantes. Con la incorporación de adiciones activas al cemento (cenizas volantes,... se amplían los estudios de este tipo de cementos. En este trabajo se considera la aplicación a los materiales silíceos (arenisca como base para la investigación del comportamiento de los morteros de arenisca conteniendo productos de reparación.

Entrapment of ovalbumin into liposomes--factors affecting entrapment efficiency, liposome size, and zeta potential.

Science.gov (United States)

Brgles, Marija; Jurasin, Darija; Sikirić, Maja Dutour; Frkanec, Ruza; Tomasić, Jelka

2008-01-01

Various amounts of Ovalbumin (OVA) were encapsulated into positively and negatively charged multilamellar liposomes, with the aim to investigate the entrapment efficiency in different buffers and to study their effects on the liposome size and zeta potential. Results showed that the entrapment efficiency of OVA in anionic liposomes was the same in 10 mM Phosphate Buffer (PB) as in Phosphate-Buffered Saline (PBS; PB + 0.15 M NaCl). Also, liposome size was approximately 1200 nm for all anionic liposomes incorporating OVA. The entrapment efficiency of OVA in cationic liposomes was highly dependent on ionic strength. The size of cationic liposomes was approximately 1200 nm in PBS, regardless of protein content, but increased with the amount of the incorporated protein in PB. Aggregation of cationic liposomes in PB was observed when the mass of the protein was 2.5 mg or greater. The zeta potential of anionic liposomes was negative and of cationic liposomes positive in the whole range of protein mass tested. These results show how different compositions of lipid and aqueous phases can be used to vary the entrapment efficiency, liposome size, and zeta potential--the factors that are of great importance for the use of liposomes as drug carriers.

Binary effectivity rules

DEFF Research Database (Denmark)

Keiding, Hans; Peleg, Bezalel

2006-01-01

is binary if it is rationalized by an acyclic binary relation. The foregoing result motivates our definition of a binary effectivity rule as the effectivity rule of some binary SCR. A binary SCR is regular if it satisfies unanimity, monotonicity, and independence of infeasible alternatives. A binary...

THE DISCOVERY OF BINARY WHITE DWARFS THAT WILL MERGE WITHIN 500 Myr

International Nuclear Information System (INIS)

Kilic, Mukremin; Brown, Warren R.; Kenyon, S. J.; Allende Prieto, Carlos; Panei, J. A.

2010-01-01

We present radial velocity observations of four extremely low-mass (0.2 M sun ) white dwarfs (WDs). All four stars show peak-to-peak radial velocity variations of 540-710 km s -1 with 1.0-5.9 hr periods. The optical photometry rules out main-sequence companions. In addition, no millisecond pulsar companions are detected in radio observations. Thus, the invisible companions are most likely WDs. Two of the systems are the shortest period binary WDs yet discovered. Due to the loss of angular momentum through gravitational radiation, three of the systems will merge within 500 Myr. The remaining system will merge within a Hubble time. The mass functions for three of the systems imply companions more massive than 0.46 M sun ; thus, those are carbon/oxygen core WDs. The unknown inclination angles prohibit a definitive conclusion about the future of these systems. However, the chance of a supernova Ia event is only 1%-5%. These systems are likely to form single R Coronae Borealis stars, providing evidence for a WD + WD merger mechanism for these unusual objects. One of the systems, SDSS J105353.89+520031.0, has a 70% chance of having a low-mass WD companion. This system will probably form a single helium-enriched subdwarf O star. All four WD systems have unusual mass ratios of ≤0.2-0.8 that may also lead to the formation of AM CVn systems.

The Stokes phenomenon and the Lerch zeta function

Directory of Open Access Journals (Sweden)

R. B. Paris

2016-05-01

Full Text Available We examine the exponentially improved asymptotic expansion of the Lerch zeta function $L(\\lambda,a,s=\\sum_{n=0}^\\infty \\exp (2\\pi ni\\lambda/(n+a^s$ for large complex values of $a$, with $\\lambda$ and $s$ regarded as parameters. It is shown that an infinite number of subdominant exponential terms switch on across the Stokes lines $\\arg\\,a=\\pm\\fs\\pi$. In addition, it is found that the transition across the upper and lower imaginary $a$-axes is associated, in general, with unequal scales. Numerical calculations are presented to confirm the theoretical predictions.

Fluctuations of quantum fields via zeta function regularization

International Nuclear Information System (INIS)

Cognola, Guido; Zerbini, Sergio; Elizalde, Emilio

2002-01-01

Explicit expressions for the expectation values and the variances of some observables, which are bilinear quantities in the quantum fields on a D-dimensional manifold, are derived making use of zeta function regularization. It is found that the variance, related to the second functional variation of the effective action, requires a further regularization and that the relative regularized variance turns out to be 2/N, where N is the number of the fields, thus being independent of the dimension D. Some illustrating examples are worked through. The issue of the stress tensor is also briefly addressed

Effect of Zeta Potential on the Properties of Nano-Drug Delivery ...

African Journals Online (AJOL)

The zeta potential (ZP) of colloidal systems and nano-medicines, as well as their particle size exert a major effect on the various properties of nano-drug delivery systems. Not only the stability of dosage forms and their release rate are affected but also their circulation in the blood stream and absorption into body membranes ...

Wind models for zeta Orionis

International Nuclear Information System (INIS)

Olson, G.L.

1979-01-01

Several models for the winds of O stars have been proposed to explain the unexpected presence of high ionization potential ions such as N +4 and O +5 . Lamers and Snow (1978) proposed that the winds of stars showing N V and O VI lines have elevated temperatures near 4 +- 2 x 10 5 K while cooler stars with anomalous Si IV lines have Tsub(e) approximately 7+-3 x 10 4 K. Alternately, Cassinelli and Olson (1978, CO) and Olson (1978) have explained the presence of these ions by showing that a thin corona at the base of a cool wind (Tsub(e) < approximately Tsub(eff)) can produce these ions by the Auger photoionization process where a single X-ray photon causes the ejection of two electrons. A third possibility is that the winds are at only slightly elevated temperatures (40 000 to 60 000K) and photoionization in an optically thick wind produces the unexpected ions. The present analysis tests the ability of these three wind models to fit the observations of zeta Orionis A 09.7 Ib. (Auth.)

Investigation on Fuzzy Logic Based Centralized Control in Four-Port SEPIC/ZETA Bidirectional Converter for Photovoltaic Applications

Directory of Open Access Journals (Sweden)

VENMATHI, M.

2016-02-01

Full Text Available In this paper, a new four-port DC-DC converter topology is proposed to interface renewable energy sources and the load along with the energy storage device. The proposed four-port SEPIC/ZETA bidirectional converter (FP-SEPIC/ZETA BDC converter comprises an isolated output port with two unidirectional and one bidirectional input ports. This converter topology is obtained by the fusion of SEPIC/ZETA BDC and full-bridge converter. This converter topology ensures the non-reversal of output voltage hence it is preferred mostly for battery charging applications. In this work, photovoltaic (PV source is considered and the power balance in the system is achieved by means of distributed maximum power point tracking (DMPPT in the PV ports. The centralized controller is implemented using fuzzy logic controller (FLC and the performance is compared with conventional proportional integral (PI controller. The results offer useful information to obtain the desired output under line and load regulations. Experimental results are also provided to validate the simulation results.

Effective flocculation of Chlorella vulgaris using chitosan with zeta potential measurement

Science.gov (United States)

Low, Y. J.; Lau, S. W.

2017-06-01

Microalgae are considered as one promising source of third-generation biofuels due to their fast growth rates, potentially higher yield rates and wide ranges of growth conditions. However, the extremely low biomass concentration in microalgae cultures presents a great challenge to the harvesting of microalgae because a large volume of water needs to be removed to obtain dry microalgal cells for the subsequent oil extraction process. In this study, the fresh water microalgae Chlorella vulgaris (C. vulgaris) was effectively harvested using both low molecular weight (MW) and high MW chitosan flocculants. The flocculation efficiency was evaluated by physical appearance, supernatant absorbance, zeta potential and solids content after centrifugal dewatering. High flocculation efficiency of 98.0-99.0% was achieved at the optimal dosage of 30-40 mg/g with formation of large microalgae flocs. This study suggests that the polymer bridging mechanism was governing the flocculation behaviour of C. vulgaris using high MW chitosan. Besides, charge patch neutralisation mechanism prevailed at low MW chitosan where lower dosage was sufficient to reach near-zero zeta potential compared with the high MW chitosan. The amount of chitosan polymer present in the culture may also affect the mechanism of flocculation.

Non-Commutative Integration, Zeta Functions and the Haar State for SU{sub q}(2)

Energy Technology Data Exchange (ETDEWEB)

Matassa, Marco, E-mail: marco.matassa@gmail.com [SISSA (Italy)

2015-12-15

We study a notion of non-commutative integration, in the spirit of modular spectral triples, for the quantum group SU{sub q}(2). In particular we define the non-commutative integral as the residue at the spectral dimension of a zeta function, which is constructed using a Dirac operator and a weight. We consider the Dirac operator introduced by Kaad and Senior and a family of weights depending on two parameters, which are related to the diagonal automorphisms of SU{sub q}(2). We show that, after fixing one of the parameters, the non-commutative integral coincides with the Haar state of SU{sub q}(2). Moreover we can impose an additional condition on the zeta function, which also fixes the second parameter. For this unique choice the spectral dimension coincides with the classical dimension.

Effects on functional groups and zeta potential of SAP1pulsed electric field technology.

Science.gov (United States)

Liang, Rong; Li, Xuenan; Lin, Songyi; Wang, Jia

2017-01-01

SAP 1 pulsed electric field (PEF) technology. The effects of electric field intensity and pulse frequency on SAP 1 electric field intensity 15 kV cm -1 , pulse frequency 1600 Hz and flow velocity 2.93 mL min -1 ). Furthermore, the PEF-treated SAP 1 < MW < 3kDa under optimal conditions lacked the characteristic absorbance of N-H, C = C and the amide band and the zeta potential was reduced to -18.0 mV. Overall, the results of the present study suggest that the improvement of antioxidant activity of SAP 1 < MW < 3kDa is a result of the contribution of the functional groups and the change in zeta potential when treated with PEF. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Electroosmotic flow of Phan-Thien-Tanner fluids at high zeta potentials: An exact analytical solution

Science.gov (United States)

Sarma, Rajkumar; Deka, Nabajit; Sarma, Kuldeep; Mondal, Pranab Kumar

2018-06-01

We present a mathematical model to study the electroosmotic flow of a viscoelastic fluid in a parallel plate microchannel with a high zeta potential, taking hydrodynamic slippage at the walls into account in the underlying analysis. We use the simplified Phan-Thien-Tanner (s-PTT) constitutive relationships to describe the rheological behavior of the viscoelastic fluid, while Navier's slip law is employed to model the interfacial hydrodynamic slip. Here, we derive analytical solutions for the potential distribution, flow velocity, and volumetric flow rate based on the complete Poisson-Boltzmann equation (without considering the frequently used Debye-Hückel linear approximation). For the underlying electrokinetic transport, this investigation primarily reveals the influence of fluid rheology, wall zeta potential as modulated by the interfacial electrochemistry and interfacial slip on the velocity distribution, volumetric flow rate, and fluid stress, as well as the apparent viscosity. We show that combined with the viscoelasticity of the fluid, a higher wall zeta potential and slip coefficient lead to a phenomenal enhancement in the volumetric flow rate. We believe that this analysis, besides providing a deep theoretical insight to interpret the transport process, will also serve as a fundamental design tool for microfluidic devices/systems under electrokinetic influence.

Certain Subclasses of Analytic and Bi-Univalent Functions Involving Double Zeta Functions

OpenAIRE

Siregar, Saibah; Raman, Sintuja

2012-01-01

In the present paper, we introduce two new subclasses of the functions class Σ of bi-univalent functions involving double zeta functions in the open unit disc U={z:zEC, |z|<1}. The estimates on the coefficients |a2| and |a3| for functions in these new subclasses of the function class Σ are obtained in our investigation.

Boundary Conditions for the Maintenance of Memory by PKM[zeta] in Neocortex

Science.gov (United States)

Shema, Reul; Hazvi, Shoshi; Sacktor, Todd C.; Dudai, Yadin

2009-01-01

We report here that ZIP, a selective inhibitor of the atypical protein kinase C isoform PKM[zeta], abolishes very long-term conditioned taste aversion (CTA) associations in the insular cortex of the behaving rat, at least 3 mo after encoding. The effect of ZIP is not replicated by a general serine/threonine protein kinase inhibitor that is…

The semi-simple zeta function of quaternionic Shimura varieties

CERN Document Server

Reimann, Harry

1997-01-01

This monograph is concerned with the Shimura variety attached to a quaternion algebra over a totally real number field. For any place of good (or moderately bad) reduction, the corresponding (semi-simple) local zeta function is expressed in terms of (semi-simple) local L-functions attached to automorphic representations. In an appendix a conjecture of Langlands and Rapoport on the reduction of a Shimura variety in a very general case is restated in a slightly stronger form. The reader is expected to be familiar with the basic concepts of algebraic geometry, algebraic number theory and the theory of automorphic representation.

Exploring the Riemann zeta function 190 years from Riemann's birth

CERN Document Server

Nikeghbali, Ashkan; Rassias, Michael

2017-01-01

This book is concerned with the Riemann Zeta Function, its generalizations, and various applications to several scientific disciplines, including Analytic Number Theory, Harmonic Analysis, Complex Analysis and Probability Theory. Eminent experts in the field illustrate both old and new results towards the solution of long-standing problems and include key historical remarks. Offering a unified, self-contained treatment of broad and deep areas of research, this book will be an excellent tool for researchers and graduate students working in Mathematics, Mathematical Physics, Engineering and Cryptography.

Broadway teatrites näeb Denzel Washingtoni ja Catherine Zeta-Jonesi / Andres Laasik

Index Scriptorium Estoniae

Laasik, Andres, 1960-2016

2010-01-01

New Yorgis välja antud Tony teatriauhinna pälvisid filminäitlejad Denzel Washington, Catherine Zeta-Jones ja Scarlett Johansson. Parim lavale naasnud näidend - "Piirdeaed", parim uus näidend - draama "Punane", mis räägib läti päritolu maalikunstnikust Mark Rothkost. Parim muusikal - "Memphis"

'Syncing' Up with the Quinn-Rand-Strogatz Constant: Hurwitz-ZetaFunctions in Non-Linear physics

Energy Technology Data Exchange (ETDEWEB)

Durgin, Natalie J.; Garcia, Sofia M.; Flournoy, Tamara; Bailey,David H.

2007-12-01

This work extends the analytical and computationalinvestigation of the Quinn-Rand-Strogatz (QRS) constants from non-linearphysics. The QRS constants (c1, c2, ..., cN) are found in a Winfreeoscillator mean-field system used to examine the transition of coupledoscillators as they lose synchronization. The constants are part of anasymptotic expansion of a function related to the oscillatorsynchronization. Previous work used high-precision software packages toevaluate c1 to 42 decimal-digits, which made it possible to recognize andprove that c1 was the root of a certain Hurwitz-zeta function. Thisallowed a value of c2 to beconjectured in terms of c1. Therefore thereis interest in determining the exact values of these constants to highprecision in the hope that general relationships can be establishedbetween the constants and the zeta functions. Here, we compute the valuesof the higher order constants (c3, c4) to more than 42-digit precision byextending an algorithm developed by D.H. Bailey, J.M. Borwein and R.E.Crandall. Several methods for speeding up the computation are exploredand an alternate proof that c1 is the root of a Hurwitz-zeta function isattempted.

Mutations in the maize zeta-carotene desaturase gene lead to viviparous kernel.

Directory of Open Access Journals (Sweden)

Yan Chen

Full Text Available Preharvest sprouting reduces the maize quality and causes a significant yield loss in maize production. vp-wl2 is a Mutator (Mu-induced viviparous mutant in maize, causing white or pale yellow kernels, dramatically reduced carotenoid and ABA content, and a high level of zeta-carotene accumulation. Here, we reported the cloning of the vp-wl2 gene using a modified digestion-ligation-amplification method (DLA. The results showed that an insertion of Mu9 in the first intron of the zeta-carotene desaturase (ZDS gene results in the vp-wl2 mutation. Previous studies have suggested that ZDS is likely the structural gene of the viviparous9 (vp9 locus. Therefore, we performed an allelic test using vp-wl2 and three vp9 mutants. The results showed that vp-wl2 is a novel allele of the vp9 locus. In addition, the sequences of ZDS gene were identified in these three vp9 alleles. The vp-wl2 mutant gene was subsequently introgressed into four maize inbred lines, and a viviparous phenotype was observed with yield losses from 7.69% to 13.33%.

Zeta potential study of Sb2S3 nanoparticles synthesized by a facile polyol method in various surfactants

Science.gov (United States)

Saxena, Monika; Okram, Gunadhor Singh

2018-05-01

In the present work, we report the successful synthesis of stibnite Sb2S3 nanoparticles (NPs) by a facile polyol method using various surfactant. The structural and optical properties were investigated by X-ray diffraction (XRD), Raman spectroscopy and Zeta potential. Rietveld refinement of XRD data confirms the single phase orthorhombic crystal structure of stibnite Sb2S3. Presence of six obvious Raman modes further confirmed their stoichiometric formation. Effect of different surfactants on the surface charge of Sb2S3 NPs was studied using Zeta potential measurement in deionized water at different pH values. They reveal that these NPs are more stable when it was synthesized in presence of EDTA than that of CTAB or without surfactant samples with high zeta potential. The isoelectronic point was found at pH = 6.4 for pure sample, 3.5 and 7.2 for CTAB and not found for EDTA Sb2S3 samples. This information can be useful for many industrial applications like pharmaceuticals, ceramics, waste water treatment and medicines.

Justification of the zeta-function renormalization in rigid string model

International Nuclear Information System (INIS)

Nesterenko, V.V.; Pirozhenko, I.G.

1997-01-01

A consistent procedure for regularization of divergences and for the subsequent renormalization of the string tension is proposed in the framework of the one-loop calculation of the interquark potential generated by the Polyakov-Kleinert string. In this way, a justification of the formal treatment of divergences by analytic continuation of the Riemann and Epstein-Hurwitz zeta-functions is given. A spectral representation for the renormalized string energy at zero temperature is derived, which enables one to find the Casimir energy in this string model at nonzero temperature very easy

Unusual poles of the {zeta}-functions for some regular singular differential operators

Energy Technology Data Exchange (ETDEWEB)

Falomir, H [IFLP, Departamento de Fisica-Facultad de Ciencias Exactas, UNLP, CC 67 (1900) La Plata (Argentina); Muschietti, M A [Departamento de Matematica-Facultad de Ciencias Exactas, UNLP, CC 172 (1900) La Plata (Argentina); Pisani, P A G [IFLP, Departamento de Fisica-Facultad de Ciencias Exactas, UNLP, CC 67 (1900) La Plata (Argentina); Seeley, R [University of Massachusetts at Boston, Boston, MA 02125 (United States)

2003-10-03

We consider the resolvent of a system of first-order differential operators with a regular singularity, admitting a family of self-adjoint extensions. We find that the asymptotic expansion for the resolvent in the general case presents powers of {lambda} which depend on the singularity, and can take even irrational values. The consequences for the pole structure of the corresponding {zeta}- and {eta}-functions are also discussed.

Stability of fenbendazole suspensions for veterinary use. Correlation between zeta potential and sedimentation.

Science.gov (United States)

Arias, José L; López-Viota, Margarita; Clares, Beatriz; Ruiz, Ma Adolfina

2008-08-07

In this paper we have carried out a detailed investigation of the stability and redispersibility characteristics of fenbendazole aqueous suspensions, through a thermodynamic and electrokinetic characterization, considering the effect of both pH and ionic strength. The hydrophobic character of the drug, and the surface charge and electrical double-layer thickness play an essential role in the stability of the system, hence the need for a full characterization of fenbendazole. It was found that the drug suspensions displays "delayed" or "hindered" sedimentation, determined by their hydrophobic character and their low zeta potential (indicating a small electrokinetic charge on the particles). The electrostatic repulsion between the particles is responsible for the low sedimentation volume and poor redispersibility of the drug. However, only low concentrations of AlCl(3) induced a significant effect on both the zeta potential and stability of the drug, leading to a "free-layered" sedimentation and a very easy redispersion which could be of great interest in the design of an oral pharmaceutical dosage form for veterinary.

On the irrationality measure for a q-analogue of \\zeta(2)

Science.gov (United States)

Zudilin, W. V.

2002-08-01

A Liouville-type estimate is proved for the irrationality measure of the quantities \\displaystyle \\zeta_q(2)=\\sum_{n=1}^\\infty\\frac{q^n}{(1-q^n)^2}with q^{-1}\\in\\mathbb Z\\setminus\\{0,\\pm1\\}. The proof is based on the application of a q-analogue of the arithmetic method developed by Chudnovsky, Rukhadze, and Hata and of the transformation group for hypergeometric series-the group-structure approach introduced by Rhin and Viola.

Ten physical applications of spectral zeta functions

CERN Document Server

Elizalde, Emilio

2012-01-01

Zeta-function regularization is a powerful method in perturbation theory, and this book is a comprehensive guide for the student of this subject. Everything is explained in detail, in particular the mathematical difficulties and tricky points, and several applications are given to show how the procedure works in practice, for example in the Casimir effect, gravity and string theory, high-temperature phase transition, topological symmetry breaking, and non-commutative spacetime. The formulae, some of which are new, can be directly applied in creating physically meaningful, accurate numerical calculations. The book acts both as a basic introduction and a collection of exercises for those who want to apply this regularization procedure in practice. Thoroughly revised, updated and expanded, this new edition includes novel, explicit formulas on the general quadratic, the Chowla-Selberg series case, an interplay with the Hadamard calculus, and also features a fresh chapter on recent cosmological applications, inclu...

Resonance chains in open systems, generalized zeta functions and clustering of the length spectrum

International Nuclear Information System (INIS)

Barkhofen, S; Faure, F; Weich, T

2014-01-01

In many non-integrable open systems in physics and mathematics, resonances have been found to be surprisingly ordered along curved lines in the complex plane. In this article we provide a unifying approach to these resonance chains by generalizing dynamical zeta functions. By means of a detailed numerical study we show that these generalized zeta functions explain the mechanism that creates the chains of quantum resonance and classical Ruelle resonances for three-disk systems as well as geometric resonances on Schottky surfaces. We also present a direct system-intrinsic definition of the continuous lines on which the resonances are strung together as a projection of an analytic variety. Additionally, this approach shows that the existence of resonance chains is directly related to a clustering of the classical length spectrum on multiples of a base length. Finally, this link is used to construct new examples where several different structures of resonance chains coexist. (paper)

RNA secondary structures in a polymer-zeta model how foldings should be shaped for sparsification to establish a linear speedup

DEFF Research Database (Denmark)

Jin, Emma Yu; Nebel, M. E.

2016-01-01

that the corresponding conditional probabilities behave according to a polymer-zeta probability model. We show that even if some of the structural parameters exhibit an almost realistic behavior on average, the expected shape of a folding in that model must be assumed to highly differ from those observed in nature. More...... sparsification) may reduce the runtime to n2 on average, assuming that nucleotides of distance d form a hydrogen bond (i.e. are paired) with probability (Formula Presented.) for some constants b > 0, c > 1. The latter is called the polymer-zeta model and plays a crucial role in speeding up the above mentioned...... algorithm. In this paper we discuss the application of the polymer-zeta property for the analysis of sparsification, showing that it must be applied conditionally on first and last positions to pair. Afterwards, we will investigate the combinatorics of RNA secondary structures assuming...

Effects of image charges, interfacial charge discreteness, and surface roughness on the zeta potential of spherical electric double layers.

Science.gov (United States)

Gan, Zecheng; Xing, Xiangjun; Xu, Zhenli

2012-07-21

We investigate the effects of image charges, interfacial charge discreteness, and surface roughness on spherical electric double layer structures in electrolyte solutions with divalent counterions in the setting of the primitive model. By using Monte Carlo simulations and the image charge method, the zeta potential profile and the integrated charge distribution function are computed for varying surface charge strengths and salt concentrations. Systematic comparisons were carried out between three distinct models for interfacial charges: (1) SURF1 with uniform surface charges, (2) SURF2 with discrete point charges on the interface, and (3) SURF3 with discrete interfacial charges and finite excluded volume. By comparing the integrated charge distribution function and the zeta potential profile, we argue that the potential at the distance of one ion diameter from the macroion surface is a suitable location to define the zeta potential. In SURF2 model, we find that image charge effects strongly enhance charge inversion for monovalent interfacial charges, and strongly suppress charge inversion for multivalent interfacial charges. For SURF3, the image charge effect becomes much smaller. Finally, with image charges in action, we find that excluded volumes (in SURF3) suppress charge inversion for monovalent interfacial charges and enhance charge inversion for multivalent interfacial charges. Overall, our results demonstrate that all these aspects, i.e., image charges, interfacial charge discreteness, their excluding volumes, have significant impacts on zeta potentials of electric double layers.

Pulsars in binary systems: probing binary stellar evolution and general relativity.

Science.gov (United States)

Stairs, Ingrid H

2004-04-23

Radio pulsars in binary orbits often have short millisecond spin periods as a result of mass transfer from their companion stars. They therefore act as very precise, stable, moving clocks that allow us to investigate a large set of otherwise inaccessible astrophysical problems. The orbital parameters derived from high-precision binary pulsar timing provide constraints on binary evolution, characteristics of the binary pulsar population, and the masses of neutron stars with different mass-transfer histories. These binary systems also test gravitational theories, setting strong limits on deviations from general relativity. Surveys for new pulsars yield new binary systems that increase our understanding of all these fields and may open up whole new areas of physics, as most spectacularly evidenced by the recent discovery of an extremely relativistic double-pulsar system.

Zeta potential control in decontamination with inorganic membranes and inorganic adsorbents

Energy Technology Data Exchange (ETDEWEB)

Andalaft, E; Vega, R; Correa, M; Araya, R; Loyola, P [Comision Chilena de Energia Nuclear, Santiago (Chile)

1997-02-01

The application of some advanced separation processes such as microfiltration and ultrafiltration, electroosmosis and electrodialysis for treating nuclear waste from different aqueous streams is under examination at the Chilean Commission for Nuclear Energy. The application of these techniques can be extended to regular industrial wastes when economically advisable. This report deals mainly with electrodialysis, electroosmosis and adsorption with inorganic materials. Special attention is paid to zeta potential control as a driving factor to electroosmosis. For radioactive contaminants that are present in the form of cations, anions, non-ionic solutions, colloids and suspended matter, appropriate combination of the processes may considerably increase the efficiency of processes used. As an example, colloids and suspended particles may be retained in porous ceramic membranes by nanofiltration, ultrafiltration or microfiltration depending on the particle size of the particles. The control of zeta potential by acting in the solid phase or else on the liquid phase has been studied; a mathematical model to predict electrodialysis data has been developed, and finally, the use of a home-made inorganic adsorbent illustrated. The effect of gamma irradiation on the membranes has also been studied. Properties such as salt retention, water flux and pore size diameter determined on both organic and inorganic membranes before and after irradiation indicate deterioration of the organic membrane. (author). 13 refs, 15 figs, 2 tabs.

Zeta potential control in decontamination with inorganic membranes and inorganic adsorbents

International Nuclear Information System (INIS)

Andalaft, E.; Vega, R.; Correa, M.; Araya, R.; Loyola, P.

1997-01-01

The application of some advanced separation processes such as microfiltration and ultrafiltration, electroosmosis and electrodialysis for treating nuclear waste from different aqueous streams is under examination at the Chilean Commission for Nuclear Energy. The application of these techniques can be extended to regular industrial wastes when economically advisable. This report deals mainly with electrodialysis, electroosmosis and adsorption with inorganic materials. Special attention is paid to zeta potential control as a driving factor to electroosmosis. For radioactive contaminants that are present in the form of cations, anions, non-ionic solutions, colloids and suspended matter, appropriate combination of the processes may considerably increase the efficiency of processes used. As an example, colloids and suspended particles may be retained in porous ceramic membranes by nanofiltration, ultrafiltration or microfiltration depending on the particle size of the particles. The control of zeta potential by acting in the solid phase or else on the liquid phase has been studied; a mathematical model to predict electrodialysis data has been developed, and finally, the use of a home-made inorganic adsorbent illustrated. The effect of gamma irradiation on the membranes has also been studied. Properties such as salt retention, water flux and pore size diameter determined on both organic and inorganic membranes before and after irradiation indicate deterioration of the organic membrane. (author). 13 refs, 15 figs, 2 tabs

Visualizing the transient electroosmotic flow and measuring the zeta potential of microchannels with a micro-PIV technique.

Science.gov (United States)

Yan, Deguang; Nguyen, Nam-Trung; Yang, Chun; Huang, Xiaoyang

2006-01-14

We have demonstrated a transient micro particle image velocimetry (micro-PIV) technique to measure the temporal development of electroosmotic flow in microchannels. Synchronization of different trigger signals for the laser, the CCD camera, and the high-voltage switch makes this measurement possible with a conventional micro-PIV setup. Using the transient micro-PIV technique, we have further proposed a method on the basis of inertial decoupling between the particle electrophoretic motion and the fluid electroosmotic flow to determine the electrophoretic component in the particle velocity and the zeta potential of the channel wall. It is shown that using the measured zeta potentials, the theoretical predictions agree well with the transient response of the electroosmotic velocities measured in this work.

Trojan Binaries

Science.gov (United States)

Noll, K. S.

2017-12-01

The Jupiter Trojans, in the context of giant planet migration models, can be thought of as an extension of the small body populations found beyond Neptune in the Kuiper Belt. Binaries are a distinctive feature of small body populations in the Kuiper Belt with an especially high fraction apparent among the brightest Cold Classicals. The binary fraction, relative sizes, and separations in the dynamically excited populations (Scattered, Resonant) reflects processes that may have eroded a more abundant initial population. This trend continues in the Centaurs and Trojans where few binaries have been found. We review new evidence including a third resolved Trojan binary and lightcurve studies to understand how the Trojans are related to the small body populations that originated in the outer protoplanetary disk.

Towards the Development of Global Nano-Quantitative Structure–Property Relationship Models: Zeta Potentials of Metal Oxide Nanoparticles

Directory of Open Access Journals (Sweden)

Andrey A. Toropov

2018-04-01

Full Text Available Zeta potential indirectly reflects a charge of the surface of nanoparticles in solutions and could be used to represent the stability of the colloidal solution. As processes of synthesis, testing and evaluation of new nanomaterials are expensive and time-consuming, so it would be helpful to estimate an approximate range of properties for untested nanomaterials using computational modeling. We collected the largest dataset of zeta potential measurements of bare metal oxide nanoparticles in water (87 data points. The dataset was used to develop quantitative structure–property relationship (QSPR models. Essential features of nanoparticles were represented using a modified simplified molecular input line entry system (SMILES. SMILES strings reflected the size-dependent behavior of zeta potentials, as the considered quasi-SMILES modification included information about both chemical composition and the size of the nanoparticles. Three mathematical models were generated using the Monte Carlo method, and their statistical quality was evaluated (R2 for the training set varied from 0.71 to 0.87; for the validation set, from 0.67 to 0.82; root mean square errors for both training and validation sets ranged from 11.3 to 17.2 mV. The developed models were analyzed and linked to aggregation effects in aqueous solutions.

14-3-3 zeta is a molecular target in guggulsterone induced apoptosis in Head and Neck cancer cells

International Nuclear Information System (INIS)

Macha, Muzafar A; Matta, Ajay; Chauhan, SS; Siu, KW Michael; Ralhan, Ranju

2010-01-01

The five-year survival rates for head and neck squamous cell carcinoma (HNSCC) patients are less than 50%, and the prognosis has not improved, despite advancements in standard multi-modality therapies. Hence major emphasis is being laid on identification of novel molecular targets and development of multi-targeted therapies. 14-3-3 zeta, a multifunctional phospho-serine/phospho-threonine binding protein, is emerging as an effector of pro-survival signaling by binding to several proteins involved in apoptosis (Bad, FKHRL1 and ASK1) and may serve as an appropriate target for head and neck cancer therapy. Herein, we determined effect of guggulsterone (GS), a farnesoid X receptor antagonist, on 14-3-3 zeta associated molecular pathways for abrogation of apoptosis in head and neck cancer cells. Head and neck cancer cells were treated with guggulsterone (GS). Effect of GS-treatment was evaluated using cell viability (MTT) assay and apoptosis was verified by annexin V, DNA fragmentation and M30 CytoDeath antibody assay. Mechanism of GS-induced apoptosis was determined by western blotting and co-IP assays using specific antibodies. Using in vitro models of head and neck cancer, we showed 14-3-3 zeta as a key player regulating apoptosis in GS treated SCC4 cells. Treatment with GS releases BAD from the inhibitory action of 14-3-3 zeta in proliferating HNSCC cells by activating protein phosphatase 2A (PP2A). These events initiate the intrinsic mitochondrial pathway of apoptosis, as revealed by increased levels of cytochrome c in cytoplasmic extracts of GS-treated SCC4 cells. In addition, GS treatment significantly reduced the expression of anti-apoptotic proteins, Bcl-2, xIAP, Mcl1, survivin, cyclin D1 and c-myc, thus committing cells to apoptosis. These events were followed by activation of caspase 9, caspase 8 and caspase 3 leading to cleavage of its downstream target, poly-ADP-ribose phosphate (PARP). GS targets 14-3-3 zeta associated cellular pathways for reducing

Testing the Binary Black Hole Nature of a Compact Binary Coalescence.

Science.gov (United States)

Krishnendu, N V; Arun, K G; Mishra, Chandra Kant

2017-09-01

We propose a novel method to test the binary black hole nature of compact binaries detectable by gravitational wave (GW) interferometers and, hence, constrain the parameter space of other exotic compact objects. The spirit of the test lies in the "no-hair" conjecture for black holes where all properties of a Kerr black hole are characterized by its mass and spin. The method relies on observationally measuring the quadrupole moments of the compact binary constituents induced due to their spins. If the compact object is a Kerr black hole (BH), its quadrupole moment is expressible solely in terms of its mass and spin. Otherwise, the quadrupole moment can depend on additional parameters (such as the equation of state of the object). The higher order spin effects in phase and amplitude of a gravitational waveform, which explicitly contains the spin-induced quadrupole moments of compact objects, hence, uniquely encode the nature of the compact binary. Thus, we argue that an independent measurement of the spin-induced quadrupole moment of the compact binaries from GW observations can provide a unique way to distinguish binary BH systems from binaries consisting of exotic compact objects.

Binary Masking & Speech Intelligibility

DEFF Research Database (Denmark)

Boldt, Jesper

The purpose of this thesis is to examine how binary masking can be used to increase intelligibility in situations where hearing impaired listeners have difficulties understanding what is being said. The major part of the experiments carried out in this thesis can be categorized as either experime......The purpose of this thesis is to examine how binary masking can be used to increase intelligibility in situations where hearing impaired listeners have difficulties understanding what is being said. The major part of the experiments carried out in this thesis can be categorized as either...... experiments under ideal conditions or as experiments under more realistic conditions useful for real-life applications such as hearing aids. In the experiments under ideal conditions, the previously defined ideal binary mask is evaluated using hearing impaired listeners, and a novel binary mask -- the target...... binary mask -- is introduced. The target binary mask shows the same substantial increase in intelligibility as the ideal binary mask and is proposed as a new reference for binary masking. In the category of real-life applications, two new methods are proposed: a method for estimation of the ideal binary...

Interacting binary stars

CERN Document Server

Sahade, Jorge; Ter Haar, D

1978-01-01

Interacting Binary Stars deals with the development, ideas, and problems in the study of interacting binary stars. The book consolidates the information that is scattered over many publications and papers and gives an account of important discoveries with relevant historical background. Chapters are devoted to the presentation and discussion of the different facets of the field, such as historical account of the development in the field of study of binary stars; the Roche equipotential surfaces; methods and techniques in space astronomy; and enumeration of binary star systems that are studied

Uncoupling of T Cell Receptor Zeta Chain Function during the Induction of Anergy by the Superantigen, Staphylococcal Enterotoxin A

Directory of Open Access Journals (Sweden)

William D. Cornwell

2010-06-01

Full Text Available Staphylococcus aureus enterotoxins have immunomodulatory properties. In this study, we show that Staphylococcal enterotoxin A (SEA induces a strong proliferative response in a murine T cell clone independent of MHC class II bearing cells. SEA stimulation also induces a state of hypo-responsiveness (anergy. We characterized the components of the T cell receptor (TCR during induction of anergy by SEA. Most interestingly, TCR zeta chain phosphorylation was absent under SEA anergizing conditions, which suggests an uncoupling of zeta chain function. We characterize here a model system for studying anergy in the absence of confounding costimulatory signals.

Full Ionisation In Binary-Binary Encounters With Small Positive Energies

Science.gov (United States)

Sweatman, W. L.

2006-08-01

Interactions between binary stars and single stars and binary stars and other binary stars play a key role in the dynamics of a dense stellar system. Energy can be transferred between the internal dynamics of a binary and the larger scale dynamics of the interacting objects. Binaries can be destroyed and created by the interaction. In a binary-binary encounter, full ionisation occurs when both of the binary stars are destroyed in the interaction to create four single stars. This is only possible when the total energy of the system is positive. For very small energies the probability of this occurring is very low and it tends towards zero as the total energy tends towards zero. Here the case is considered for which all the stars have equal masses. An asymptotic power law is predicted relating the probability of full ionisation with the total energy when this latter quantity is small. The exponent, which is approximately 2.31, is compared with the results from numerical scattering experiments. The theoretical approach taken is similar to one used previously in the three-body problem. It makes use of the fact that the most dramatic changes in scale and energies of a few-body system occur when its components pass near to a central configuration. The position, and number, of these configurations is not known for the general four-body problem, however, with equal masses there are known to be exactly five different cases. Separate consideration and comparison of the properties of orbits close to each of these five central configurations enables the prediction of the form of the cross-section for full ionisation for the case of small positive total energy. This is the relation between total energy and the probability of total ionisation described above.

Interlaboratory comparison for the measurement of particle size and zeta potential of silica nanoparticles in an aqueous suspension

Science.gov (United States)

Lamberty, Andrée; Franks, Katrin; Braun, Adelina; Kestens, Vikram; Roebben, Gert; Linsinger, Thomas P. J.

2011-12-01

The Institute for Reference Materials and Measurements has organised an interlaboratory comparison (ILC) to allow the participating laboratories to demonstrate their proficiency in particle size and zeta potential measurements on monomodal aqueous suspensions of silica nanoparticles in the 10-100 nm size range. The main goal of this ILC was to identify competent collaborators for the production of certified nanoparticle reference materials. 38 laboratories from four different continents participated in the ILC with different methods for particle sizing and determination of zeta potential. Most of the laboratories submitted particle size results obtained with centrifugal liquid sedimentation (CLS), dynamic light scattering (DLS) or electron microscopy (EM), or zeta potential values obtained via electrophoretic light scattering (ELS). The results of the laboratories were evaluated using method-specific z scores, calculated on the basis of consensus values from the ILC. For CLS (13 results) and EM (13 results), all reported values were within the ±2 | z| interval. For DLS, 25 of the 27 results reported were within the ±2 | z| interval, the two other results were within the ±3 | z| interval. The standard deviations of the corresponding laboratory mean values varied between 3.7 and 6.5%, which demonstrates satisfactory interlaboratory comparability of CLS, DLS and EM particle size values. From the received test reports, a large discrepancy was observed in terms of the laboratory's quality assurance systems, which are equally important for the selection of collaborators in reference material certification projects. Only a minority of the participating laboratories is aware of all the items that are mandatory in test reports compliant to ISO/IEC 17025 (ISO General requirements for the competence of testing and calibration laboratories. International Organisation for Standardization, Geneva, 2005b). The absence of measurement uncertainty values in the reports, for

CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. I. S-TYPE BINARIES

Energy Technology Data Exchange (ETDEWEB)

Kaltenegger, Lisa [MPIA, Koenigstuhl 17, D-69117 Heidelberg (Germany); Haghighipour, Nader, E-mail: kaltenegger@mpia.de [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Manoa, Honolulu, HI 96822 (United States)

2013-11-10

We have developed a comprehensive methodology for calculating the boundaries of the habitable zone (HZ) of planet-hosting S-type binary star systems. Our approach is general and takes into account the contribution of both stars to the location and extent of the binary HZ with different stellar spectral types. We have studied how the binary eccentricity and stellar energy distribution affect the extent of the HZ. Results indicate that in binaries where the combination of mass-ratio and orbital eccentricity allows planet formation around a star of the system to proceed successfully, the effect of a less luminous secondary on the location of the primary's HZ is generally negligible. However, when the secondary is more luminous, it can influence the extent of the HZ. We present the details of the derivations of our methodology and discuss its application to the binary HZ around the primary and secondary main-sequence stars of an FF, MM, and FM binary, as well as two known planet-hosting binaries α Cen AB and HD 196886.

CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. I. S-TYPE BINARIES

International Nuclear Information System (INIS)

Kaltenegger, Lisa; Haghighipour, Nader

2013-01-01

We have developed a comprehensive methodology for calculating the boundaries of the habitable zone (HZ) of planet-hosting S-type binary star systems. Our approach is general and takes into account the contribution of both stars to the location and extent of the binary HZ with different stellar spectral types. We have studied how the binary eccentricity and stellar energy distribution affect the extent of the HZ. Results indicate that in binaries where the combination of mass-ratio and orbital eccentricity allows planet formation around a star of the system to proceed successfully, the effect of a less luminous secondary on the location of the primary's HZ is generally negligible. However, when the secondary is more luminous, it can influence the extent of the HZ. We present the details of the derivations of our methodology and discuss its application to the binary HZ around the primary and secondary main-sequence stars of an FF, MM, and FM binary, as well as two known planet-hosting binaries α Cen AB and HD 196886

Effect of Tannic Acid on the zeta Potential, Sorption, and Surface Free Energy in the Process of Dyeing of Leacril with a Cationic Dye.

Science.gov (United States)

Espinosa-Jiménez; Giménez-Martín; Ontiveros-Ortega

1998-11-01

The behavior of the surface free energy in the process of dyeing Leacril pretreated with tannic acid and subsequently dyeing with the cationic dye Rhodamine B has been studied. Also the electrokinetic behavior of these systems has been analyzed by studying the zeta potential, which has been obtained by means of the streaming potential technique. Values more significative of the zeta potential of these systems have been obtained using the three models of capillaries existing in the literature. The qualitative behavior of the zeta potential is the same for the three models of capillaries tested in this paper. These models are those of Goring and Mason, Biefer and Mason, and Chang and Robertson. The zeta potential of the systems analyzed is negative in the range of concentration of the dye in the liquid phase from 10(-6) to ca. 10(-4) M of dye. In the range of low concentrations (from 10(-6) to ca. 10(-5) M of dye) the zeta potential of the system untreated Leacril/Rhodamine B increases in absolute value due to increasing hydrophobic attractions between both the hydrophobic chains of the dye and the Leacril fibers in aqueous media. In the system Leacril treated with tannic acid/Rhodamine B, this increase is also due to the presence of hydrogen bonding between the phenolic hydroxyl groups of the tannic acid and the sulfonate and sulfate end groups of Leacril fibers. For concentrations of dye between 10(-5) and 10(-4) M of dye in solution, the zeta potential decreases in absolute value due to the electrostatic attractions between the groups negatively charged in the fiber and the cation of the dye. The zeta potential changes its sign at the highest concentrations of dye used in this work. The adsorption of Rhodamine B onto both untreated Leacril and Leacril treated with tannic acid is favored by the increasing temperature of adsorption. The behavior of the components of the surface free energy obtained by the thin-layer wicking technique led us to consider that the

Epoetin zeta in the management of anemia associated with chronic kidney disease, differential pharmacology and clinical utility

Directory of Open Access Journals (Sweden)

Davis-Ajami ML

2014-04-01

Full Text Available Mary Lynn Davis-Ajami,1 Jun Wu,2 Katherine Downton,3 Emilie Ludeman,3 Virginia Noxon4 1Organizational Systems and Adult Health, University of Maryland School of Nursing, Baltimore, MD, USA; 2South Carolina College of Pharmacy, University of South Carolina, Greenville, SC, USA; 3Health Sciences and Human Services Library, University of Maryland, Baltimore, MD, USA; 4Department of Clinical Pharmacy and Outcomes Science, South Carolina College of Pharmacy, University of South Carolina, Columbia, SC, USA Abstract: Epoetin zeta was granted marketing authorization in October 2007 by the European Medicines Agency as a recombinant human erythropoietin erythropoiesis-stimulating agent to treat symptomatic anemia of renal origin in adult and pediatric patients on hemodialysis and adults on peritoneal dialysis, as well as for symptomatic renal anemia in adult patients with renal insufficiency not yet on dialysis. Currently, epoetin zeta can be administered either subcutaneously or intravenously to correct for hemoglobin concentrations ≤10 g/dL (6.2 mmol/L or with dose adjustment to maintain hemoglobin levels at desired levels not in excess of 12 g/dL (7.5 mmol/L. This review article focuses on epoetin zeta indications in chronic kidney disease, its use in managing anemia of renal origin, and discusses its pharmacology and clinical utility. Keywords: biosimilar, chronic kidney disease, epoetin alfa, erythropoiesis, renal anemia, Retacrit®

Interacting binaries

CERN Document Server

Shore, S N; van den Heuvel, EPJ

1994-01-01

This volume contains lecture notes presented at the 22nd Advanced Course of the Swiss Society for Astrophysics and Astronomy. The contributors deal with symbiotic stars, cataclysmic variables, massive binaries and X-ray binaries, in an attempt to provide a better understanding of stellar evolution.

Eclipsing binaries in open clusters

DEFF Research Database (Denmark)

Southworth, John; Clausen, J.V.

2006-01-01

Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August......Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August...

CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. II. P-TYPE BINARIES

International Nuclear Information System (INIS)

Haghighipour, Nader; Kaltenegger, Lisa

2013-01-01

We have developed a comprehensive methodology for calculating the circumbinary habitable zone (HZ) in planet-hosting P-type binary star systems. We present a general formalism for determining the contribution of each star of the binary to the total flux received at the top of the atmosphere of an Earth-like planet and use the Sun's HZ to calculate the inner and outer boundaries of the HZ around a binary star system. We apply our calculations to the Kepler's currently known circumbinary planetary systems and show the combined stellar flux that determines the boundaries of their HZs. We also show that the HZ in P-type systems is dynamic and, depending on the luminosity of the binary stars, their spectral types, and the binary eccentricity, its boundaries vary as the stars of the binary undergo their orbital motion. We present the details of our calculations and discuss the implications of the results

CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. II. P-TYPE BINARIES

Energy Technology Data Exchange (ETDEWEB)

Haghighipour, Nader [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Manoa, Honolulu, HI 96822 (United States); Kaltenegger, Lisa [MPIA, Koenigstuhl 17, Heidelberg, D-69117 (Germany)

2013-11-10

We have developed a comprehensive methodology for calculating the circumbinary habitable zone (HZ) in planet-hosting P-type binary star systems. We present a general formalism for determining the contribution of each star of the binary to the total flux received at the top of the atmosphere of an Earth-like planet and use the Sun's HZ to calculate the inner and outer boundaries of the HZ around a binary star system. We apply our calculations to the Kepler's currently known circumbinary planetary systems and show the combined stellar flux that determines the boundaries of their HZs. We also show that the HZ in P-type systems is dynamic and, depending on the luminosity of the binary stars, their spectral types, and the binary eccentricity, its boundaries vary as the stars of the binary undergo their orbital motion. We present the details of our calculations and discuss the implications of the results.

A Possible Massive Asteroid Belt Around $\\zeta$ Lep

CERN Document Server

Chen Chuan Hung

2001-01-01

We have used the Keck I telescope to image at 11.7 microns and 17.9 microns the dust emission around zeta Lep, a main sequence A-type star at 21.5 pc from the Sun with an infrared excess. The excess is at most marginally resolved at 17.9 microns. The dust distance from the star is probably less than or equal to 6 AU, although some dust may extend to 9 AU. The mass of observed dust is \\~10^22 g. Since the lifetime of dust particles is about 10,000 years because of the Poytning-Robertson effect, we robustly estimate at least 4 10^26 g must reside in parent bodies which may be asteroids if the system is in a steady state and has an age of ~300 Myr. This mass is approximately 200 times that contained within the main asteroid belt in our solar system.

Statistical properties of the zeros of zeta functions - beyond the Riemann case

International Nuclear Information System (INIS)

Bogomolny, E.; Leboeuf, P.

1993-09-01

The statistical distribution of the zeros of Dirichlet L-functions is investigated both analytically and numerically. Using the Hardy-Littlewood conjecture about the distribution of primes it is shown that the two-point correlation function of these zeros coincides with that for eigenvalues of the Gaussian unitary ensemble of random matrices, and that the distributions of zeros of different L-functions are statistically independent. Applications of these results to Epstein's zeta functions are shortly discussed. (authors) 30 refs., 3 figs., 1 tab

Massive Black Hole Binary Evolution

Directory of Open Access Journals (Sweden)

Merritt David

2005-11-01

Full Text Available Coalescence of binary supermassive black holes (SBHs would constitute the strongest sources of gravitational waves to be observed by LISA. While the formation of binary SBHs during galaxy mergers is almost inevitable, coalescence requires that the separation between binary components first drop by a few orders of magnitude, due presumably to interaction of the binary with stars and gas in a galactic nucleus. This article reviews the observational evidence for binary SBHs and discusses how they would evolve. No completely convincing case of a bound, binary SBH has yet been found, although a handful of systems (e.g. interacting galaxies; remnants of galaxy mergers are now believed to contain two SBHs at projected separations of <~ 1kpc. N-body studies of binary evolution in gas-free galaxies have reached large enough particle numbers to reproduce the slow, “diffusive” refilling of the binary’s loss cone that is believed to characterize binary evolution in real galactic nuclei. While some of the results of these simulations - e.g. the binary hardening rate and eccentricity evolution - are strongly N-dependent, others - e.g. the “damage” inflicted by the binary on the nucleus - are not. Luminous early-type galaxies often exhibit depleted cores with masses of ~ 1-2 times the mass of their nuclear SBHs, consistent with the predictions of the binary model. Studies of the interaction of massive binaries with gas are still in their infancy, although much progress is expected in the near future. Binary coalescence has a large influence on the spins of SBHs, even for mass ratios as extreme as 10:1, and evidence of spin-flips may have been observed.

Cataclysmic Variables and Active Binary Stars in Omega Centauri

Science.gov (United States)

Arias, T.; Brochmann, M.; Dorfman, J. L.; White, M. V.; Cool, A. M.

2004-12-01

We report findings from our ongoing research on the globular cluster Omega Centauri (NGC 5139) using a 3x3 mosaic of Wide Field Camera pointings with the HST Advanced Camera for Surveys (ACS). The data consist of F435W (B435), F625W (R625), and F658N (Hα ) images and cover roughly 10x10 arcminutes, out to beyond the cluster's half-mass radius. Our current work is a search for cataclysmic variables (CVs) and active binaries (ABs) (e.g., RS CVn and BY Dra stars) as counterparts to X-ray point sources previously detected with Chandra. The ACS field encompasses 109 of the Chandra sources, 20-50 of which are likely to be cluster members according to our statistical estimates (the rest being primarily active galaxies). Using DAOPHOT to obtain photometry in 20x20 arcsecond patches surrounding each X-ray source, we are constructing color-magnitude diagrams to search for stars with Hα -R625 and/or B435-R625 colors indicative of CVs or ABs in ˜ 1 arcsecond Chandra error circles. With roughly half of the patches analyzed, several AB candidates and only a small number of CV candidates have emerged. Our tentative conclusion is that CVs may be significantly rarer in Omega Cen than in 47 Tuc, in contrast to the comparable numbers ( ˜100) predicted for these two clusters from tidal capture theory (Di Stefano and Rappaport 1994). Alternatively, the CVs could be strongly concentrated toward the cluster center, and thus not yet appear in our sample. To date, most of the patches we have analyzed are 3-4 arcminutes from the cluster center and thus are outside the cluster core (radius 2.6 arcminutes). Our continuing work should soon enable us to resolve this question. This work is supported by NASA grant GO-9442 from the Space Telescope Science Institute.

Observations of the Star Cor Caroli at the Apple Valley Workshop 2016 (Abstract)

Science.gov (United States)

Estrada, R.; Boyd, S.; Estrada, C.; Evans, C.; Rhoades, H.; Rhoades, M.; Rhoades, T.

2017-12-01

(Abstract only) Using a 22-inch Newtonian Alt/Az telescope and Celestron Micro Guide eyepiece, students participating in a workshop observed the binary star Cor Caroli (STF 1692; alpha CVn) and found a position angle of 231.0 degrees as well as an average separation of 18.7" This observation compared favorably with the 2015 Washington Double Star published position. This project was part of Mark Brewer's Apple Valley Double Star Workshop. The results were analyzed using bias and circle error probability calculations.

A zeta potential value determines the aggregate's size of penta-substituted [60]fullerene derivatives in aqueous suspension whereas positive charge is required for toxicity against bacterial cells.

Science.gov (United States)

Deryabin, Dmitry G; Efremova, Ludmila V; Vasilchenko, Alexey S; Saidakova, Evgeniya V; Sizova, Elena A; Troshin, Pavel A; Zhilenkov, Alexander V; Khakina, Ekaterina A; Khakina, Ekaterina E

2015-08-08

The cause-effect relationships between physicochemical properties of amphiphilic [60]fullerene derivatives and their toxicity against bacterial cells have not yet been clarified. In this study, we report how the differences in the chemical structure of organic addends in 10 originally synthesized penta-substituted [60]fullerene derivatives modulate their zeta potential and aggregate's size in salt-free and salt-added aqueous suspensions as well as how these physicochemical characteristics affect the bioenergetics of freshwater Escherichia coli and marine Photobacterium phosphoreum bacteria. Dynamic light scattering, laser Doppler micro-electrophoresis, agarose gel electrophoresis, atomic force microscopy, and bioluminescence inhibition assay were used to characterize the fullerene aggregation behavior in aqueous solution and their interaction with the bacterial cell surface, following zeta potential changes and toxic effects. Dynamic light scattering results indicated the formation of self-assembled [60]fullerene aggregates in aqueous suspensions. The measurement of the zeta potential of the particles revealed that they have different surface charges. The relationship between these physicochemical characteristics was presented as an exponential regression that correctly described the dependence of the aggregate's size of penta-substituted [60]fullerene derivatives in salt-free aqueous suspension from zeta potential value. The prevalence of DLVO-related effects was shown in salt-added aqueous suspension that decreased zeta potential values and affected the aggregation of [60]fullerene derivatives expressed differently for individual compounds. A bioluminescence inhibition assay demonstrated that the toxic effect of [60]fullerene derivatives against E. coli cells was strictly determined by their positive zeta potential charge value being weakened against P. phosphoreum cells in an aquatic system of high salinity. Atomic force microscopy data suggested that the

Reduced Zeta potential through use of cationic adhesion promoter for improved resist process performance and minimizing material consumption

Science.gov (United States)

Hodgson, Lorna; Thompson, Andrew

2012-03-01

This paper presents the results of a non-HMDS (non-silane) adhesion promoter that was used to reduce the zeta potential for very thin (proprietary) polymer on silicon. By reducing the zeta potential, as measured by the minimum sample required to fully coat a wafer, the amount of polymer required to coat silicon substrates was significantly reduced in the manufacture of X-ray windows used for high transmission of low-energy X-rays. Moreover, this approach used aqueous based adhesion promoter described as a cationic surface active agent that has been shown to improve adhesion of photoresists (positive, negative, epoxy [SU8], e-beam and dry film). As well as reducing the amount of polymer required to coat substrates, this aqueous adhesion promoter is nonhazardous, and contains non-volatile solvents.

The fate of close encounters between binary stars and binary supermassive black holes

Science.gov (United States)

Wang, Yi-Han; Leigh, Nathan; Yuan, Ye-Fei; Perna, Rosalba

2018-04-01

The evolution of main-sequence binaries that reside in the Galactic Centre can be heavily influenced by the central supermassive black hole (SMBH). Due to these perturbative effects, the stellar binaries in dense environments are likely to experience mergers, collisions, or ejections through secular and/or non-secular interactions. More direct interactions with the central SMBH are thought to produce hypervelocity stars (HVSs) and tidal disruption events (TDEs). In this paper, we use N-body simulations to study the dynamics of stellar binaries orbiting a central SMBH primary with an outer SMBH secondary orbiting this inner triple. The effects of the secondary SMBH on the event rates of HVSs, TDEs, and stellar mergers are investigated, as a function of the SMBH-SMBH binary mass ratio. Our numerical experiments reveal that, relative to the isolated SMBH case, the TDE and HVS rates are enhanced for, respectively, the smallest and largest mass ratio SMBH-SMBH binaries. This suggests that the observed event rates of TDEs and HVSs have the potential to serve as a diagnostic of the mass ratio of a central SMBH-SMBH binary. The presence of a secondary SMBH also allows for the creation of hypervelocity binaries. Observations of these systems could thus constrain the presence of a secondary SMBH in the Galactic Centre.

Solving a binary puzzle

NARCIS (Netherlands)

Utomo, P.H.; Makarim, R.H.

2017-01-01

A Binary puzzle is a Sudoku-like puzzle with values in each cell taken from the set {0,1} {0,1}. Let n≥4 be an even integer, a solved binary puzzle is an n×n binary array that satisfies the following conditions: (1) no three consecutive ones and no three consecutive zeros in each row and each

Flotation of algae for water reuse and biomass production: role of zeta potential and surfactant to separate algal particles.

Science.gov (United States)

Kwak, Dong-Heui; Kim, Mi-Sug

2015-01-01

The effect of chemical coagulation and biological auto-flocculation relative to zeta potential was examined to compare flotation and sedimentation separation processes for algae harvesting. Experiments revealed that microalgae separation is related to auto-flocculation of Anabaena spp. and requires chemical coagulation for the whole period of microalgae cultivation. In addition, microalgae separation characteristics which are associated with surfactants demonstrated optimal microalgae cultivation time and separation efficiency of dissolved CO2 flotation (DCF) as an alternative to dissolved air flotation (DAF). Microalgae were significantly separated in response to anionic surfactant rather than cationic surfactant as a function of bubble size and zeta potential. DAF and DCF both showed slightly efficient flotation; however, application of anionic surfactant was required when using DCF.

Relations between elliptic multiple zeta values and a special derivation algebra

International Nuclear Information System (INIS)

Broedel, Johannes; Matthes, Nils; Schlotterer, Oliver

2016-01-01

We investigate relations between elliptic multiple zeta values (eMZVs) and describe a method to derive the number of indecomposable elements of given weight and length. Our method is based on representing eMZVs as iterated integrals over Eisenstein series and exploiting the connection with a special derivation algebra. Its commutator relations give rise to constraints on the iterated integrals over Eisenstein series relevant for eMZVs and thereby allow to count the indecomposable representatives. Conversely, the above connection suggests apparently new relations in the derivation algebra. Under https://tools.aei.mpg.de/emzv we provide relations for eMZVs over a wide range of weights and lengths. (paper)

Fractional parts and their relations to the values of the Riemann zeta function

KAUST Repository

Alabdulmohsin, Ibrahim

2017-09-06

A well-known result, due to Dirichlet and later generalized by de la Vallée–Poussin, expresses a relationship between the sum of fractional parts and the Euler–Mascheroni constant. In this paper, we prove an asymptotic relationship between the summation of the products of fractional parts with powers of integers on the one hand, and the values of the Riemann zeta function, on the other hand. Dirichlet’s classical result falls as a particular case of this more general theorem.

Fractional parts and their relations to the values of the Riemann zeta function

KAUST Repository

Alabdulmohsin, Ibrahim

2017-01-01

A well-known result, due to Dirichlet and later generalized by de la Vallée–Poussin, expresses a relationship between the sum of fractional parts and the Euler–Mascheroni constant. In this paper, we prove an asymptotic relationship between the summation of the products of fractional parts with powers of integers on the one hand, and the values of the Riemann zeta function, on the other hand. Dirichlet’s classical result falls as a particular case of this more general theorem.

Generalized zeta function representation of groups and 2-dimensional topological Yang-Mills theory: The example of GL(2, _q) and PGL(2, _q)

International Nuclear Information System (INIS)

Roche, Ph.

2016-01-01

We recall the relation between zeta function representation of groups and two-dimensional topological Yang-Mills theory through Mednikh formula. We prove various generalisations of Mednikh formulas and define generalization of zeta function representations of groups. We compute some of these functions in the case of the finite group GL(2, _q) and PGL(2, _q). We recall the table characters of these groups for any q, compute the Frobenius-Schur indicator of their irreducible representations, and give the explicit structure of their fusion rings.

H{sub 2} EXCITATION STRUCTURE ON THE SIGHTLINES TO {delta} SCORPII AND {zeta} OPHIUCI: FIRST RESULTS FROM THE SUB-ORBITAL LOCAL INTERSTELLAR CLOUD EXPERIMENT

Energy Technology Data Exchange (ETDEWEB)

France, Kevin; Nell, Nicholas; Kane, Robert; Green, James C. [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Burgh, Eric B. [SOFIA/USRA, NASA Ames Research Center, M/S N232-12, Moffett Field, CA 94035 (United States); Beasley, Matthew, E-mail: kevin.france@colorado.edu [Planetary Resources, Inc., 93 S Jackson St 50680, Seattle, WA 98104-2818 (United States)

2013-07-20

We present the first science results from the Sub-orbital Local Interstellar Cloud Experiment (SLICE): moderate resolution 1020-1070 A spectroscopy of four sightlines through the local interstellar medium. High signal-to-noise (S/N) spectra of {eta} Uma, {alpha} Vir, {delta} Sco, and {zeta} Oph were obtained during a 2013 April 21 rocket flight. The SLICE observations constrain the density, molecular photoexcitation rates, and physical conditions present in the interstellar material toward {delta} Sco and {zeta} Oph. Our spectra indicate a factor of two lower total N(H{sub 2}) than previously reported for {delta} Sco, which we attribute to higher S/N and better scattered light control in the new SLICE observations. We find N(H{sub 2}) = 1.5 Multiplication-Sign 10{sup 19} cm{sup -2} on the {delta} Sco sightline, with kinetic and excitation temperatures of 67 and 529 K, respectively, and a cloud density of n{sub H} = 56 cm{sup -3}. Our observations of the bulk of the molecular sightline toward {zeta} Oph are consistent with previous measurements (N(H{sub 2}) Almost-Equal-To 3 Multiplication-Sign 10{sup 20} cm{sup -2} at T{sub 01}(H{sub 2}) = 66 K and T{sub exc} = 350 K). However, we detect significantly more rotationally excited H{sub 2} toward {zeta} Oph than previously observed. We infer a cloud density in the rotationally excited component of n{sub H} Almost-Equal-To 7600 cm{sup -3} and suggest that the increased column densities of excited H{sub 2} are a result of the ongoing interaction between {zeta} Oph and its environment; also manifest as the prominent mid-IR bowshock observed by WISE and the presence of vibrationally excited H{sub 2} molecules observed by the Hubble Space Telescope.

Casimir energies in M4≥/sup N/ for even N. Green's-function and zeta-function techniques

International Nuclear Information System (INIS)

Kantowski, R.; Milton, K.A.

1987-01-01

The Green's-function technique developed in the first paper in this series is generalized to apply to massive scalar, vector, second-order tensor, and Dirac spinor fields, as a preliminary to a full graviton calculation. The Casimir energies are of the form u/sub Casimir/ = (1/a 4 )[α/sub N/lna/b)+β/sub N/], where N (even) is the dimension of the internal sphere, a is its radius, and b/sup -1/ is an ultraviolet cutoff (presumably at the Planck scale). The coefficient of the divergent logarithm, α/sub N/, is unambiguously obtained for each field considered. The Green's-function technique gives rise to no difficulties in the evaluation of imaginary-mass-mode contributions to the Casimir energy. In addition, a new, simplified zeta-function technique is presented which is very easily implemented by symbolic programs, and which, of course, gives the same results. An error in a previous zeta-function calculation of the Casimir energy for even N is pointed out

Relativistic Binaries in Globular Clusters

Directory of Open Access Journals (Sweden)

Matthew J. Benacquista

2013-03-01

Full Text Available Galactic globular clusters are old, dense star systems typically containing 10^4 – 10^6 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of tight binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker–Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

Skewed Binary Search Trees

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Moruz, Gabriel

2006-01-01

It is well-known that to minimize the number of comparisons a binary search tree should be perfectly balanced. Previous work has shown that a dominating factor over the running time for a search is the number of cache faults performed, and that an appropriate memory layout of a binary search tree...... can reduce the number of cache faults by several hundred percent. Motivated by the fact that during a search branching to the left or right at a node does not necessarily have the same cost, e.g. because of branch prediction schemes, we in this paper study the class of skewed binary search trees....... For all nodes in a skewed binary search tree the ratio between the size of the left subtree and the size of the tree is a fixed constant (a ratio of 1/2 gives perfect balanced trees). In this paper we present an experimental study of various memory layouts of static skewed binary search trees, where each...

Using System Architecture, Review Entry Criteria, and Standard Work Package Data to Enable Rapid Development of Integrated Master Schedules

Science.gov (United States)

2016-03-01

critical path, EVM, project management, systems engineering, CVN, obsolescence , integrated master schedule , portfolio schedule 15. NUMBER OF PAGES...after the decision to swap deployments between the CVN-69 and CVN-75. C. COTS OBSOLESCENCE While CVN deadlines impose schedule constraints...Elements The context diagram shows how a CVN IT program SEP and IMS interact with COTS obsolescence , the CPA availability schedule , and other internal

Binary optics: Trends and limitations

Science.gov (United States)

Farn, Michael W.; Veldkamp, Wilfrid B.

1993-01-01

We describe the current state of binary optics, addressing both the technology and the industry (i.e., marketplace). With respect to the technology, the two dominant aspects are optical design methods and fabrication capabilities, with the optical design problem being limited by human innovation in the search for new applications and the fabrication issue being limited by the availability of resources required to improve fabrication capabilities. With respect to the industry, the current marketplace does not favor binary optics as a separate product line and so we expect that companies whose primary purpose is the production of binary optics will not represent the bulk of binary optics production. Rather, binary optics' more natural role is as an enabling technology - a technology which will directly result in a competitive advantage in a company's other business areas - and so we expect that the majority of binary optics will be produced for internal use.

HST-WFC3 Near-Infrared Spectroscopy of Quenched Galaxies at zeta approx 1.5 from the WISP Survey: Stellar Populations Properties

Science.gov (United States)

Bedregal, A. G.; Scarlata, C.; Henry, A. L.; Atek, H.; Rafelski, M.; Teplitz, H. I.; Dominguez, A.; Siana, B.; Colbert, J. W.; Malkan, M.;

Black holes in binary stars

NARCIS (Netherlands)

Wijers, R.A.M.J.

1996-01-01

Introduction Distinguishing neutron stars and black holes Optical companions and dynamical masses X-ray signatures of the nature of a compact object Structure and evolution of black-hole binaries High-mass black-hole binaries Low-mass black-hole binaries Low-mass black holes Formation of black holes

Coevolution of Binaries and Circumbinary Gaseous Disks

Science.gov (United States)

Fleming, David; Quinn, Thomas R.

2018-04-01

The recent discoveries of circumbinary planets by Kepler raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disk, and how the disk and binary interact. The central binary excites resonances in the surrounding protoplanetary disk that drive evolution in both the binary orbital elements and in the disk. To probe how these interactions impact both binary eccentricity and disk structure evolution, we ran N-body smooth particle hydrodynamics (SPH) simulations of gaseous protoplanetary disks surrounding binaries based on Kepler 38 for 10^4 binary orbital periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disk via a parametric instability and excite disk eccentricity growth. Eccentric binaries strongly couple to the disk causing eccentricity growth for both the disk and binary. Disks around sufficiently eccentric binaries strongly couple to the disk and develop an m = 1 spiral wave launched from the 1:3 eccentric outer Lindblad resonance (EOLR). This wave corresponds to an alignment of gas particle longitude of periastrons. We find that in all simulations, the binary semi-major axis decays due to dissipation from the viscous disk.

BINARY CEPHEIDS: SEPARATIONS AND MASS RATIOS IN 5 M ☉ BINARIES

International Nuclear Information System (INIS)

Evans, Nancy Remage; Karovska, Margarita; Tingle, Evan; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.

2013-01-01

Deriving the distribution of binary parameters for a particular class of stars over the full range of orbital separations usually requires the combination of results from many different observing techniques (radial velocities, interferometry, astrometry, photometry, direct imaging), each with selection biases. However, Cepheids—cool, evolved stars of ∼5 M ☉ —are a special case because ultraviolet (UV) spectra will immediately reveal any companion star hotter than early type A, regardless of the orbital separation. We have used International Ultraviolet Explorer UV spectra of a complete sample of all 76 Cepheids brighter than V = 8 to create a list of all 18 Cepheids with companions more massive than 2.0 M ☉ . Orbital periods of many of these binaries are available from radial-velocity studies, or can be estimated for longer-period systems from detected velocity variability. In an imaging survey with the Hubble Space Telescope Wide Field Camera 3, we resolved three of the companions (those of η Aql, S Nor, and V659 Cen), allowing us to make estimates of the periods out to the long-period end of the distribution. Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations, orbital periods, and mass ratios. The distribution of orbital periods shows that the 5 M ☉ binaries have systematically shorter periods than do 1 M ☉ stars. Our data also suggest that the distribution of mass ratios depends on both binary separation and system multiplicity. The distribution of mass ratios as a function of orbital separation, however, does not depend on whether a system is a binary or a triple

Spectral properties of binary asteroids

Science.gov (United States)

Pajuelo, Myriam; Birlan, Mirel; Carry, Benoît; DeMeo, Francesca E.; Binzel, Richard P.; Berthier, Jérôme

2018-04-01

We present the first attempt to characterize the distribution of taxonomic class among the population of binary asteroids (15% of all small asteroids). For that, an analysis of 0.8-2.5{μ m} near-infrared spectra obtained with the SpeX instrument on the NASA/IRTF is presented. Taxonomic class and meteorite analog is determined for each target, increasing the sample of binary asteroids with known taxonomy by 21%. Most binary systems are bound in the S-, X-, and C- classes, followed by Q and V-types. The rate of binary systems in each taxonomic class agrees within uncertainty with the background population of small near-Earth objects and inner main belt asteroids, but for the C-types which are under-represented among binaries.

Detection of interstellar (C-13)N toward Zeta Ophiuchi

International Nuclear Information System (INIS)

Crane, P.; Hegyi, D.J.

1988-01-01

Observations of a diffuse interstellar cloud toward Zeta Oph, obtained with resolution 100,000-150,000 near the 3874.608-A R(0) line of (C-12)N using a coude echelle spectrograph on the 1.4-m telescope at ESO during 1984 and 1985, are reported. Data from 54 20-min runs were fitted to Gaussian line shapes using the line center, depth, and width of the R(0) and R(1) lines of (C-12)N and the line center and depth of the R(0) line of (C-13)N as fitting parameters. The (C-13)N R(0) line, with equivalent width 0.190 + or - 0.020 mA, was detected 173.7 + or - 0.8 mA to the red of (C-12)N R(0); the corresponding isotope abundance ratio, (C-12)N/(C-13)N = 47.3 + 5.5 or -4.4, is shown to be in good agreement with previous measurements for CH(+) (Hawkins et al., 1985). 13 references

Failure to synthesize the human T-cell CD3-zeta chain and its consequence for the T-cell receptor-CD3 complex expression

DEFF Research Database (Denmark)

Geisler, C; Kuhlmann, J; Plesner, T

1989-01-01

components, the human T-cell tumour line Jurkat was chemically mutagenized followed by negative selection with F101.01 (a monoclonal antibody against the TcR-CD3 complex), and cloning. Growing clones were analysed for TcR-CD3 expression by immunofluorescence. One clone, J79, was found to express greatly...... diminished levels of TcR-CD3. This clone produced all the TcR-CD3 components except the CD3-zeta, as demonstrated by metabolic labelling and immunoprecipitation followed by one- and two-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis. These data indicate that the CD3-zeta determines...

Applications of Wirtinger Inequalities on the Distribution of Zeros of the Riemann Zeta-Function

Directory of Open Access Journals (Sweden)

Saker SamirH

2010-01-01

Full Text Available On the hypothesis that the th moments of the Hardy -function are correctly predicted by random matrix theory and the moments of the derivative of are correctly predicted by the derivative of the characteristic polynomials of unitary matrices, we establish new large spaces between the zeros of the Riemann zeta-function by employing some Wirtinger-type inequalities. In particular, it is obtained that which means that consecutive nontrivial zeros often differ by at least 6.1392 times the average spacing.

Binary Cepheids: Separations and Mass Ratios in 5 M ⊙ Binaries

Science.gov (United States)

Evans, Nancy Evans; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.; Karovska, Margarita; Tingle, Evan

2013-10-01

Deriving the distribution of binary parameters for a particular class of stars over the full range of orbital separations usually requires the combination of results from many different observing techniques (radial velocities, interferometry, astrometry, photometry, direct imaging), each with selection biases. However, Cepheids—cool, evolved stars of ~5 M ⊙—are a special case because ultraviolet (UV) spectra will immediately reveal any companion star hotter than early type A, regardless of the orbital separation. We have used International Ultraviolet Explorer UV spectra of a complete sample of all 76 Cepheids brighter than V = 8 to create a list of all 18 Cepheids with companions more massive than 2.0 M ⊙. Orbital periods of many of these binaries are available from radial-velocity studies, or can be estimated for longer-period systems from detected velocity variability. In an imaging survey with the Hubble Space Telescope Wide Field Camera 3, we resolved three of the companions (those of η Aql, S Nor, and V659 Cen), allowing us to make estimates of the periods out to the long-period end of the distribution. Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations, orbital periods, and mass ratios. The distribution of orbital periods shows that the 5 M ⊙ binaries have systematically shorter periods than do 1 M ⊙ stars. Our data also suggest that the distribution of mass ratios depends on both binary separation and system multiplicity. The distribution of mass ratios as a function of orbital separation, however, does not depend on whether a system is a binary or a triple. Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained by the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

The formation of eccentric compact binary inspirals and the role of gravitational wave emission in binary-single stellar encounters

International Nuclear Information System (INIS)

Samsing, Johan; MacLeod, Morgan; Ramirez-Ruiz, Enrico

2014-01-01

The inspiral and merger of eccentric binaries leads to gravitational waveforms distinct from those generated by circularly merging binaries. Dynamical environments can assemble binaries with high eccentricity and peak frequencies within the LIGO band. In this paper, we study binary-single stellar scatterings occurring in dense stellar systems as a source of eccentrically inspiraling binaries. Many interactions between compact binaries and single objects are characterized by chaotic resonances in which the binary-single system undergoes many exchanges before reaching a final state. During these chaotic resonances, a pair of objects has a non-negligible probability of experiencing a very close passage. Significant orbital energy and angular momentum are carried away from the system by gravitational wave (GW) radiation in these close passages, and in some cases this implies an inspiral time shorter than the orbital period of the bound third body. We derive the cross section for such dynamical inspiral outcomes through analytical arguments and through numerical scattering experiments including GW losses. We show that the cross section for dynamical inspirals grows with increasing target binary semi-major axis a and that for equal-mass binaries it scales as a 2/7 . Thus, we expect wide target binaries to predominantly contribute to the production of these relativistic outcomes. We estimate that eccentric inspirals account for approximately 1% of dynamically assembled non-eccentric merging binaries. While these events are rare, we show that binary-single scatterings are a more effective formation channel than single-single captures for the production of eccentrically inspiraling binaries, even given modest binary fractions.

The influence of zeta potential and yield stress on the filtration characteristics of a magnesium hydroxide simulant

International Nuclear Information System (INIS)

Biggs, Simon; Nabi, Rafiq; Poole, Colin; Patel, Ashok

2007-01-01

In the UK, irradiated fuels from Magnox reactors are often stored in water-filled ponds under alkaline conditions, so as to minimise corrosion of fuel cladding. This is important to prevent or reduce leakage of soluble fission products and actinides to the pond water. A variety of intermediate level wastes derived from Magnox materials are stored at power stations. Under these alkaline conditions, various species of magnesium are formed, of which magnesium hydroxide is the dominant material. The particle-fluid interactions are significant for the design and operation of facilities for hydraulic retrieval, filtration, dewatering and ion exchange treatment of fuel storage pond water and stored wet Magnox wastes. Here we describe a study of particulate properties and filtration characteristics of oxide particle simulants under laboratory conditions. Cake and medium resistance data were correlated across a range of pH conditions with electro-acoustic zeta potential and shear yield stress measurements, as a function of particle volume fractions. The influence of zeta potential on filtration properties arises directly from the interaction of particles within the sediment cake. (authors)

N-Bit Binary Resistor

Science.gov (United States)

Tcheng, Ping

1989-01-01

Binary resistors in series tailored to precise value of resistance. Desired value of resistance obtained by cutting appropriate traces across resistors. Multibit, binary-based, adjustable resistor with high resolution used in many applications where precise resistance required.

Some properties of spectral binary stars

International Nuclear Information System (INIS)

Krajcheva, Z.T.; Popova, E.I.; Tutukov, A.V.; Yungel'son, L.R.; AN SSSR, Moscow. Astronomicheskij Sovet)

1978-01-01

Statistical investigations of spectra binary stars are carried out. Binary systems consisting of main sequence stars are considered. For 826 binary stars masses of components, ratios of component masses, semiaxes of orbits and orbital angular momenta are calculated. The distributions of these parameters and their correlations are analyzed. The dependences of statistical properties of spectral binary stars on their origin and evolution are discussed

Microlensing Binaries Discovered through High-magnification Channel

DEFF Research Database (Denmark)

Shin, I.-G.; Choi, J.-Y.; Park, S.-Y.

2012-01-01

Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of eight binary-lensing events detected through the channel of high-magnification events during the seasons from 2007 to 2010. The perturba......Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of eight binary-lensing events detected through the channel of high-magnification events during the seasons from 2007 to 2010...

Performance analysis and binary working fluid selection of combined flash-binary geothermal cycle

International Nuclear Information System (INIS)

Zeyghami, Mehdi

2015-01-01

Performance of the combined flash-binary geothermal power cycle for geofluid temperatures between 150 and 250 °C is studied. A thermodynamic model is developed, and the suitable binary working fluids for different geofluid temperatures are identified from a list of thirty working fluid candidates, consisting environmental friendly refrigerants and hydrocarbons. The overall system exergy destruction and Vapor Expansion Ratio across the binary cycle turbine are selected as key performance indicators. The results show that for low-temperature heat sources using refrigerants as binary working fluids result in higher overall cycle efficiency and for medium and high-temperature resources, hydrocarbons are more suitable. For combined flash-binary cycle, secondary working fluids; R-152a, Butane and Cis-butane show the best performances at geofluid temperatures 150, 200 and 250 °C respectively. The overall second law efficiency is calculated as high as 0.48, 0.55 and 0.58 for geofluid temperatures equal 150, 200 and 250 °C respectively. The flash separator pressure found to has important effects on cycle operation and performance. Separator pressure dictates the work production share of steam and binary parts of the system. And there is an optimal separator pressure at which overall exergy destruction of the cycle achieves its minimum value. - Highlights: • Performance of the combined flash-binary geothermal cycle is investigated. • Thirty different fluids are screened to find the most suitable ORC working fluid. • Optimum cycle operation conditions presented for geofluids between 150 °C and 250 °C. • Refrigerants are more suitable for the ORC at geothermal sources temperature ≤200 °C. • Hydrocarbons are more suitable for the ORC at geothermal sources temperature >200 °C

BINARY CEPHEIDS: SEPARATIONS AND MASS RATIOS IN 5 M {sub ☉} BINARIES

Energy Technology Data Exchange (ETDEWEB)

Evans, Nancy Remage; Karovska, Margarita; Tingle, Evan [Smithsonian Astrophysical Observatory, MS 4, 60 Garden Street, Cambridge, MA 02138 (United States); Bond, Howard E. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Schaefer, Gail H. [The CHARA Array, Georgia State University, P.O. Box 3965, Atlanta, GA 30302-3965 (United States); Mason, Brian D., E-mail: nevans@cfa.harvard.edu, E-mail: heb11@psu.edu, E-mail: schaefer@chara-array.org [US Naval Observatory, 3450 Massachusetts Avenue, NW, Washington, DC 20392-5420 (United States)

2013-10-01

Deriving the distribution of binary parameters for a particular class of stars over the full range of orbital separations usually requires the combination of results from many different observing techniques (radial velocities, interferometry, astrometry, photometry, direct imaging), each with selection biases. However, Cepheids—cool, evolved stars of ∼5 M {sub ☉}—are a special case because ultraviolet (UV) spectra will immediately reveal any companion star hotter than early type A, regardless of the orbital separation. We have used International Ultraviolet Explorer UV spectra of a complete sample of all 76 Cepheids brighter than V = 8 to create a list of all 18 Cepheids with companions more massive than 2.0 M {sub ☉}. Orbital periods of many of these binaries are available from radial-velocity studies, or can be estimated for longer-period systems from detected velocity variability. In an imaging survey with the Hubble Space Telescope Wide Field Camera 3, we resolved three of the companions (those of η Aql, S Nor, and V659 Cen), allowing us to make estimates of the periods out to the long-period end of the distribution. Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations, orbital periods, and mass ratios. The distribution of orbital periods shows that the 5 M {sub ☉} binaries have systematically shorter periods than do 1 M {sub ☉} stars. Our data also suggest that the distribution of mass ratios depends on both binary separation and system multiplicity. The distribution of mass ratios as a function of orbital separation, however, does not depend on whether a system is a binary or a triple.

Dissipative binary collisions

International Nuclear Information System (INIS)

Aboufirassi, M; Angelique, J.C.; Bizard, G.; Bougault, R.; Brou, R.; Buta, A.; Colin, J.; Cussol, D.; Durand, D.; Genoux-Lubain, A.; Horn, D.; Kerambrun, A.; Laville, J.L.; Le Brun, C.; Lecolley, J.F.; Lefebvres, F.; Lopez, O.; Louvel, M.; Meslin, C.; Metivier, V.; Nakagawa, T.; Peter, J.; Popescu, R.; Regimbart, R.; Steckmeyer, J.C.; Tamain, B.; Vient, E.; Wieloch, A.; Yuasa-Nakagawa, K.

1998-01-01

The binary character of the heavy ion collisions at intermediate energies in the exit channel has been observed under 30 MeV/n in medium and heavy systems. Measurements in light systems at energies approaching ∼ 100 MeV/nucleon as well as in very heavy systems have allowed to extend considerably the investigations of this binary process. Thus, the study of the Pb + Au system showed that the complete charge events indicated two distinct sources: the quasi-projectile and the quasi-target. The characteristics of these two sources are rather well reproduced by a trajectory computation which takes into account the Coulomb and nuclear forces and the friction appearing from the projectile-target interaction. The Wilczynski diagram is used to probe the correlation between the kinetic energy quenching and the deflecting angle. In case of the system Pb + Au at 29 MeV/nucleon the diagram indicate dissipative binary collisions typical for low energies. This binary aspect was also detected in the systems Xe + Ag at 44 MeV/nucleon, 36 Ar + 27 Al and 64 Zn + nat Ti. Thus, it was possible to reconstruct the quasi-projectile and to study its mass and excitation energy evolution as a function of the impact parameter. The dissipative binary collisions represent for the systems and energies under considerations the main contribution to the cross section. This does not implies that there are not other processes; particularly, the more or less complete fusion is also observed but with a low cross section which decreases with the increase of bombardment energy. More exclusive measurements with the INDRA detector on quasi-symmetric systems as Ar + KCl and Xe + Sn seem to confirm the importance of the binary collisions. The two source reconstruction of the Xe + Sn data at 50 MeV/nucleon reproduces the same behaviour as that observed in the system Pb + Au at 29 MeV/nucleon

Contact Binaries on Their Way Towards Merging

Science.gov (United States)

Gazeas, K.

2015-07-01

Contact binaries are the most frequently observed type of eclipsing star system. They are small, cool, low-mass binaries belonging to a relatively old stellar population. They follow certain empirical relationships that closely connect a number of physical parameters with each other, largely because of constraints coming from the Roche geometry. As a result, contact binaries provide an excellent test of stellar evolution, specifically for stellar merger scenarios. Observing campaigns by many authors have led to the cataloging of thousands of contact binaries and enabled statistical studies of many of their properties. A large number of contact binaries have been found to exhibit extraordinary behavior, requiring follow-up observations to study their peculiarities in detail. For example, a doubly-eclipsing quadruple system consisting of a contact binary and a detached binary is a highly constrained system offering an excellent laboratory to test evolutionary theories for binaries. A new observing project was initiated at the University of Athens in 2012 in order to investigate the possible lower limit for the orbital period of binary systems before coalescence, prior to merging.

Scaling behaviour of the correlation length for the two-point correlation function in the random field Ising chain

Energy Technology Data Exchange (ETDEWEB)

Lange, Adrian; Stinchcombe, Robin [Theoretical Physics, University of Oxford, Oxford (United Kingdom)

1996-07-07

We study the general behaviour of the correlation length {zeta}(kT:h) for two-point correlation function of the local fields in an Ising chain with binary distributed fields. At zero field it is shown that {zeta} is the same as the zero-field correlation length for the spin-spin correlation function. For the field-dominated behaviour of {zeta} we find an exponent for the power-law divergence which is smaller than the exponent for the spin-spin correlation length. The entire behaviour of the correlation length can be described by a single crossover scaling function involving the new critical exponent. (author)

Permutation Entropy for Random Binary Sequences

Directory of Open Access Journals (Sweden)

Lingfeng Liu

2015-12-01

Full Text Available In this paper, we generalize the permutation entropy (PE measure to binary sequences, which is based on Shannon’s entropy, and theoretically analyze this measure for random binary sequences. We deduce the theoretical value of PE for random binary sequences, which can be used to measure the randomness of binary sequences. We also reveal the relationship between this PE measure with other randomness measures, such as Shannon’s entropy and Lempel–Ziv complexity. The results show that PE is consistent with these two measures. Furthermore, we use PE as one of the randomness measures to evaluate the randomness of chaotic binary sequences.

Binary Systems and the Initial Mass Function

Science.gov (United States)

Malkov, O. Yu.

2017-07-01

In the present paper we discuss advantages and disadvantages of binary stars, which are important for star formation history determination. We show that to make definite conclusions of the initial mass function shape, it is necessary to study binary population well enough to correct the luminosity function for unresolved binaries; to construct the mass-luminosity relation based on wide binaries data, and to separate observational mass functions of primaries, of secondaries, and of unresolved binaries.

Accuracy of binary black hole waveform models for aligned-spin binaries

Science.gov (United States)

Kumar, Prayush; Chu, Tony; Fong, Heather; Pfeiffer, Harald P.; Boyle, Michael; Hemberger, Daniel A.; Kidder, Lawrence E.; Scheel, Mark A.; Szilagyi, Bela

2016-05-01

Coalescing binary black holes are among the primary science targets for second generation ground-based gravitational wave detectors. Reliable gravitational waveform models are central to detection of such systems and subsequent parameter estimation. This paper performs a comprehensive analysis of the accuracy of recent waveform models for binary black holes with aligned spins, utilizing a new set of 84 high-accuracy numerical relativity simulations. Our analysis covers comparable mass binaries (mass-ratio 1 ≤q ≤3 ), and samples independently both black hole spins up to a dimensionless spin magnitude of 0.9 for equal-mass binaries and 0.85 for unequal mass binaries. Furthermore, we focus on the high-mass regime (total mass ≳50 M⊙ ). The two most recent waveform models considered (PhenomD and SEOBNRv2) both perform very well for signal detection, losing less than 0.5% of the recoverable signal-to-noise ratio ρ , except that SEOBNRv2's efficiency drops slightly for both black hole spins aligned at large magnitude. For parameter estimation, modeling inaccuracies of the SEOBNRv2 model are found to be smaller than systematic uncertainties for moderately strong GW events up to roughly ρ ≲15 . PhenomD's modeling errors are found to be smaller than SEOBNRv2's, and are generally irrelevant for ρ ≲20 . Both models' accuracy deteriorates with increased mass ratio, and when at least one black hole spin is large and aligned. The SEOBNRv2 model shows a pronounced disagreement with the numerical relativity simulation in the merger phase, for unequal masses and simultaneously both black hole spins very large and aligned. Two older waveform models (PhenomC and SEOBNRv1) are found to be distinctly less accurate than the more recent PhenomD and SEOBNRv2 models. Finally, we quantify the bias expected from all four waveform models during parameter estimation for several recovered binary parameters: chirp mass, mass ratio, and effective spin.

Radial Velocities of 41 Kepler Eclipsing Binaries

Science.gov (United States)

Matson, Rachel A.; Gies, Douglas R.; Guo, Zhao; Williams, Stephen J.

2017-12-01

Eclipsing binaries are vital for directly determining stellar parameters without reliance on models or scaling relations. Spectroscopically derived parameters of detached and semi-detached binaries allow us to determine component masses that can inform theories of stellar and binary evolution. Here we present moderate resolution ground-based spectra of stars in close binary systems with and without (detected) tertiary companions observed by NASA’s Kepler mission and analyzed for eclipse timing variations. We obtain radial velocities and spectroscopic orbits for five single-lined and 35 double-lined systems, and confirm one false positive eclipsing binary. For the double-lined spectroscopic binaries, we also determine individual component masses and examine the mass ratio {M}2/{M}1 distribution, which is dominated by binaries with like-mass pairs and semi-detached classical Algol systems that have undergone mass transfer. Finally, we constrain the mass of the tertiary component for five double-lined binaries with previously detected companions.

Planets in Binary Star Systems

CERN Document Server

Haghighipour, Nader

2010-01-01

The discovery of extrasolar planets over the past decade has had major impacts on our understanding of the formation and dynamical evolution of planetary systems. There are features and characteristics unseen in our solar system and unexplainable by the current theories of planet formation and dynamics. Among these new surprises is the discovery of planets in binary and multiple-star systems. The discovery of such "binary-planetary" systems has confronted astrodynamicists with many new challenges, and has led them to re-examine the theories of planet formation and dynamics. Among these challenges are: How are planets formed in binary star systems? What would be the notion of habitability in such systems? Under what conditions can binary star systems have habitable planets? How will volatiles necessary for life appear on such planets? This volume seeks to gather the current research in the area of planets in binary and multistar systems and to familiarize readers with its associated theoretical and observation...

Interpretation of colloidal dyeing of polyester fabrics pretreated with ethyl xanthogenate in terms of zeta potential and surface free energy balance.

Science.gov (United States)

Espinosa-Jiménez, M; Padilla-Weigand, R; Ontiveros-Ortega, A; Ramos-Tejada, M M; Perea-Carpio, R

2003-09-15

Data are presented on the adsorption of the colloidal dye Disperse Blue 3 onto polyester fabric (Dacron 54, Stile 777), the fabric being pretreated with different amounts of the surfactant potassium ethyl xanthogenate (PEX). This study has been made by means of both the evolution of the zeta potential of the fiber/dye interface and the behaviour of the surface free energy components of the above systems. The kinetics of adsorption of the process of dyeing, using 10(-4) M of PEX in the pretreatment of the fabric, shows that increasing temperature of adsorption decrease the amount of colloidal dye adsorbed onto the fabric. This fact shows that the principal mechanism involved in this adsorption process is physical in nature. The adsorption isotherms of the colloidal dye onto polyester pretreated with different amounts of PEX, shows that the adsorption of the dye is favored with the increase in the concentration of the surfactant used in the pretreatment. This fact shows that the pretreatment with PEX is a very interesting aspect of interest in textile industry. The zeta potential of the system fabric/surfactant shows that this parameter is negative (about -25 mV) for the untreated fiber and decreases in absolute value for increasing concentration of the surfactant on the fiber, the value of the zeta potential of the system being -5 mV for 10(-2) M of PEX. This behavior can be explained for the chemical reaction nucleophilic attack between the carboxyl groups of polyester, ionized at pH 8, and the thiocarbonyl group of the xanthogenate ion. On the other hand, the zeta potential of the system polyester pretreated with PEX/Disperse Blue 3 at increasing concentrations of the surfactant and the dye shows that this parameter increases its negative value strongly with increasing concentration of the surfactant used in the treatment. This can be explained for the hydrogen bonds between the hydroxy groups of the dye and the S- ions of the thiocarbonyl group of the surfactant

Theoretical studies of binaries in astrophysics

Science.gov (United States)

Dischler, Johann Sebastian

This thesis introduces and summarizes four papers dealing with computer simulations of astrophysical processes involving binaries. The first part gives the rational and theoretical background to these papers. In paper I and II a statistical approach to studying eclipsing binaries is described. By using population synthesis models for binaries the probabilities for eclipses are calculated for different luminosity classes of binaries. These are compared with Hipparcos data and they agree well if one uses a standard input distribution for the orbit sizes. If one uses a random pairing model, where both companions are independently picked from an IMF, one finds too feclipsing binaries by an order of magnitude. In paper III we investigate a possible scenario for the origin of the stars observed close to the centre of our galaxy, called S stars. We propose that a cluster falls radially cowards the central black hole. The binaries within the cluster can then, if they have small impact parameters, be broken up by the black hole's tidal held and one of the components of the binary will be captured by the black hole. Paper IV investigates how the onset of mass transfer in eccentric binaries depends on the eccentricity. To do this we have developed a new two-phase SPH scheme where very light particles are at tire outer edge of our simulated star. This enables us to get a much better resolution of the very small mass that is transferred in close binaries. Our simulations show that the minimum required distance between the stars to have mass transfer decreases with the eccentricity.

Mining frequent binary expressions

NARCIS (Netherlands)

Calders, T.; Paredaens, J.; Kambayashi, Y.; Mohania, M.K.; Tjoa, A.M.

2000-01-01

In data mining, searching for frequent patterns is a common basic operation. It forms the basis of many interesting decision support processes. In this paper we present a new type of patterns, binary expressions. Based on the properties of a specified binary test, such as reflexivity, transitivity

Survival of planets around shrinking stellar binaries.

Science.gov (United States)

Muñoz, Diego J; Lai, Dong

2015-07-28

The discovery of transiting circumbinary planets by the Kepler mission suggests that planets can form efficiently around binary stars. None of the stellar binaries currently known to host planets has a period shorter than 7 d, despite the large number of eclipsing binaries found in the Kepler target list with periods shorter than a few days. These compact binaries are believed to have evolved from wider orbits into their current configurations via the so-called Lidov-Kozai migration mechanism, in which gravitational perturbations from a distant tertiary companion induce large-amplitude eccentricity oscillations in the binary, followed by orbital decay and circularization due to tidal dissipation in the stars. Here we explore the orbital evolution of planets around binaries undergoing orbital decay by this mechanism. We show that planets may survive and become misaligned from their host binary, or may develop erratic behavior in eccentricity, resulting in their consumption by the stars or ejection from the system as the binary decays. Our results suggest that circumbinary planets around compact binaries could still exist, and we offer predictions as to what their orbital configurations should be like.

Close-binary central stars of planetary nebulae

International Nuclear Information System (INIS)

Bond, H.E.; Grauer, A.D.

1987-01-01

Recent observations of PN central stars identified as binary systems are reviewed. The theoretical significance of binary central stars is discussed, and the characteristics of UU Sge, V 477 Lyr, MT Ser, LSS 2018, VW Pyx, and the central star of HFG 1 are briefly summarized. All of these binaries are shown to have periods less than 1 day, and it is estimated that about 10 percent of all binary central stars are close binaries. 27 references

Bondi-Hoyle-Lyttleton Accretion onto Binaries

Science.gov (United States)

Antoni, Andrea; MacLeod, Morgan; Ramírez-Ruiz, Enrico

2018-01-01

Binary stars are not rare. While only close binary stars will eventually interact with one another, even the widest binary systems interact with their gaseous surroundings. The rates of accretion and the gaseous drag forces arising in these interactions are the key to understanding how these systems evolve. This poster examines accretion flows around a binary system moving supersonically through a background gas. We perform three-dimensional hydrodynamic simulations of Bondi-Hoyle-Lyttleton accretion using the adaptive mesh refinement code FLASH. We simulate a range of values of semi-major axis of the orbit relative to the gravitational focusing impact parameter of the pair. On large scales, gas is gravitationally focused by the center-of-mass of the binary, leading to dynamical friction drag and to the accretion of mass and momentum. On smaller scales, the orbital motion imprints itself on the gas. Notably, the magnitude and direction of the forces acting on the binary inherit this orbital dependence. The long-term evolution of the binary is determined by the timescales for accretion, slow down of the center-of-mass, and decay of the orbit. We use our simulations to measure these timescales and to establish a hierarchy between them. In general, our simulations indicate that binaries moving through gaseous media will slow down before the orbit decays.

Formation and Evolution of X-ray Binaries

Science.gov (United States)

Shao, Y.

2017-07-01

X-ray binaries are a class of binary systems, in which the accretor is a compact star (i.e., black hole, neutron star, or white dwarf). They are one of the most important objects in the universe, which can be used to study not only binary evolution but also accretion disks and compact stars. Statistical investigations of these binaries help to understand the formation and evolution of galaxies, and sometimes provide useful constraints on the cosmological models. The goal of this thesis is to investigate the formation and evolution processes of X-ray binaries including Be/X-ray binaries, low-mass X-ray binaries (LMXBs), ultraluminous X-ray sources (ULXs), and cataclysmic variables. In Chapter 1 we give a brief review on the basic knowledge of the binary evolution. In Chapter 2 we discuss the formation of Be stars through binary interaction. In this chapter we investigate the formation of Be stars resulting from mass transfer in binaries in the Galaxy. Using binary evolution and population synthesis calculations, we find that in Be/neutron star binaries the Be stars have a lower limit of mass ˜ 8 M⊙ if they are formed by a stable (i.e., without the occurrence of common envelope evolution) and nonconservative mass transfer. We demonstrate that the isolated Be stars may originate from both mergers of two main-sequence stars and disrupted Be binaries during the supernova explosions of the primary stars, but mergers seem to play a much more important role. Finally the fraction of Be stars produced by binary interactions in all B type stars can be as high as ˜ 13%-30% , implying that most of Be stars may result from binary interaction. In Chapter 3 we show the evolution of intermediate- and low-mass X-ray binaries (I/LMXBs) and the formation of millisecond pulsars. Comparing the calculated results with the observations of binary radio pulsars, we report the following results: (1) The allowed parameter space for forming binary pulsars in the initial orbital period

Modelling binary data

CERN Document Server

Collett, David

2002-01-01

INTRODUCTION Some Examples The Scope of this Book Use of Statistical Software STATISTICAL INFERENCE FOR BINARY DATA The Binomial Distribution Inference about the Success Probability Comparison of Two Proportions Comparison of Two or More Proportions MODELS FOR BINARY AND BINOMIAL DATA Statistical Modelling Linear Models Methods of Estimation Fitting Linear Models to Binomial Data Models for Binomial Response Data The Linear Logistic Model Fitting the Linear Logistic Model to Binomial Data Goodness of Fit of a Linear Logistic Model Comparing Linear Logistic Models Linear Trend in Proportions Comparing Stimulus-Response Relationships Non-Convergence and Overfitting Some other Goodness of Fit Statistics Strategy for Model Selection Predicting a Binary Response Probability BIOASSAY AND SOME OTHER APPLICATIONS The Tolerance Distribution Estimating an Effective Dose Relative Potency Natural Response Non-Linear Logistic Regression Models Applications of the Complementary Log-Log Model MODEL CHECKING Definition of Re...

The multiple zeta value data mine

International Nuclear Information System (INIS)

Buemlein, J.; Broadhurst, D.J.

2009-07-01

We provide a data mine of proven results for multiple zeta values (MZVs) of the form ζ(s 1 ,s 2 ,..,s k ) = sum ∞ n 1 >n 2 >...>n k >0 {1/(n 1 s 1 ..n k s k )} with weight w = sum K i=1 s i and depth k and for Euler sums of the form sum ∞ n 1 >n 2 >...>n k >0 {(ε 1 n 1 ..ε 1 n k )/(n 1 s 1 ..n k s k )} with signs ε i = ± 1. Notably, we achieve explicit proven reductions of all MZVs with weights w≤22, and all Euler sums with weights w≤12, to bases whose dimensions, bigraded by weight and depth, have sizes in precise agreement with the Broadhurst. Kreimer and Broadhurst conjectures. Moreover, we lend further support to these conjectures by studying even greater weights (w≤30), using modular arithmetic. To obtain these results we derive a new type of relation for Euler sums, the Generalized Doubling Relations. We elucidate the ''pushdown'' mechanism, whereby the ornate enumeration of primitive MZVs, by weight and depth, is reconciled with the far simpler enumeration of primitive Euler sums. There is some evidence that this pushdown mechanism finds its origin in doubling relations. We hope that our data mine, obtained by exploiting the unique power of the computer algebra language FORM, will enable the study of many more such consequences of the double-shuffle algebra of MZVs, and their Euler cousins, which are already the subject of keen interest, to practitioners of quantum field theory, and to mathematicians alike. (orig.)

Formation and evolution of compact binaries

NARCIS (Netherlands)

Sluijs, Marcel Vincent van der

2006-01-01

In this thesis we investigate the formation and evolution of compact binaries. Chapters 2 through 4 deal with the formation of luminous, ultra-compact X-ray binaries in globular clusters. We show that the proposed scenario of magnetic capture produces too few ultra-compact X-ray binaries to explain

Zeta potential and Raman studies of PVP capped Bi2S3 nanoparticles synthesized by polyol method

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Tarachand, Sathe, Vasant G.; Okram, Gunadhor S.

2018-05-01

Here we report the synthesis and characterisation of polyvinylpyrrolidone (PVP) capped Bi2S3 nanoparticles via one step catalyst-free polyol method. Raman spectroscopy, dynamic light scattering and zeta potential analysis were performed on it. Rietveld refinement of powder XRD of PVP capped samples confirmed the formation of single phase orthorhombic Bi2S3 for all PVP capped samples. The presence of eight obvious Raman modes further confirmed the formation of stoichiometric Bi2S3. Dynamic light scattering (DLS) studies show a clear increase in hydrodynamic diameter for samples made with increasing PVP concentration. Particle size obtained from DLS and XRD (using Scherrer's formula) combine with change in full width half maxima of Raman modes collectively suggest overall improvement in crystallinity and quality of product on introducing PVP. In zeta potential (ζ) measurement, steric hindrance of carbon chains plays very crucial role and a systematic reduction of ζ value is observed for samples made with decreasing PVP concentration. An isoelectric point is obtained for sample made with low PVP (1g). Present results are likely to open a window for its medical and catalytic applications.

Clinical Trials Using Anti-CD19/CD28/CD3zeta CAR Gammaretroviral Vector-transduced Autologous T Lymphocytes KTE-C19

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NCI supports clinical trials that test new and more effective ways to treat cancer. Find clinical trials studying anti-cd19/cd28/cd3zeta car gammaretroviral vector-transduced autologous t lymphocytes kte-c19.

Do stellar clusters form fewer binaries? Using moderate separation binaries to distinguish between nature and nurture

Science.gov (United States)

Reiter, Megan

2017-08-01

Fewer wide-separation binaries are found in dense stellar clusters than in looser stellar associations. It is therefore unclear whether feedback in clusters prevents the formation of multiple systems or dynamical interactions destroy them. Measuring the prevalence of close, bound binary systems provide a key test to distinguish between these possibilities. Systems with separations of 10-50 AU will survive interactions in the cluster environment, and therefore are more representative of the natal population of multiple systems. By fitting a double-star PSF, we will identify visual binaries in the Orion Nebula with separations as small as 0.03. At the distance of Orion, this corresponds to a physical separation of 12 AU, effectively closing the observational gap in the binary separation distribution left between known visual and spectroscopic binaries (>65 AU or PhD thesis.

Origin of very-short orbital-period binary systems

International Nuclear Information System (INIS)

Miyaji, S.

1983-01-01

Recent observations of four close binaries have established that there is a group of very-short orbital-period (VSOP) binaries whose orbital periods are less than 60 minutes. The VSOP binaries consist of both X-ray close binaries and cataclysmic variables. Their orbital periods are too short to have a main-sequence companion. However, four binaries, none of which belongs to any globular cluster, are too abundant to be explained by the capturing mechanism of a white dwarf. Therefore it seemed to be worthwhile to present an evolutionary scenario from an original binary system which can be applied for all VSOP binaries. (Auth.)

Separation in 5 Msun Binaries

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Evans, Nancy R.; Bond, H. E.; Schaefer, G.; Mason, B. D.; Karovska, M.; Tingle, E.

2013-01-01

Cepheids (5 Msun stars) provide an excellent sample for determining the binary properties of fairly massive stars. International Ultraviolet Explorer (IUE) observations of Cepheids brighter than 8th magnitude resulted in a list of ALL companions more massive than 2.0 Msun uniformly sensitive to all separations. Hubble Space Telescope Wide Field Camera 3 (WFC3) has resolved three of these binaries (Eta Aql, S Nor, and V659 Cen). Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations for a sample of 18 Cepheids, and also a distribution of mass ratios. The distribution of orbital periods shows that the 5 Msun binaries prefer shorter periods than 1 Msun stars, reflecting differences in star formation processes.

Astronomy of binary and multiple stars

International Nuclear Information System (INIS)

Tokovinin, A.A.

1984-01-01

Various types of binary stars and methods for their observation are described in a popular form. Some models of formation and evolution of binary and multiple star systems are presented. It is concluded that formation of binary and multiple stars is a regular stage in the process of star production

A ROSAT Survey of Contact Binary Stars

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Geske, M. T.; Gettel, S. J.; McKay, T. A.

2006-01-01

Contact binary stars are common variable stars that are all believed to emit relatively large fluxes of X-rays. In this work we combine a large new sample of contact binary stars derived from the ROTSE-I telescope with X-ray data from the ROSAT All Sky Survey (RASS) to estimate the X-ray volume emissivity of contact binary stars in the Galaxy. We obtained X-ray fluxes for 140 contact binaries from the RASS, as well as two additional stars observed by the XMM-Newton observatory. From these data we confirm the emission of X-rays from all contact binary systems, with typical luminosities of approximately 1.0×1030 ergs s-1. Combining calculated luminosities with an estimated contact binary space density, we find that contact binaries do not have strong enough X-ray emission to account for a significant portion of the Galactic X-ray background.

GALAXY ROTATION AND RAPID SUPERMASSIVE BINARY COALESCENCE

Energy Technology Data Exchange (ETDEWEB)

Holley-Bockelmann, Kelly [Vanderbilt University, Nashville, TN (United States); Khan, Fazeel Mahmood, E-mail: k.holley@vanderbilt.edu [Institute of Space Technology (IST), Islamabad (Pakistan)

2015-09-10

Galaxy mergers usher the supermassive black hole (SMBH) in each galaxy to the center of the potential, where they form an SMBH binary. The binary orbit shrinks by ejecting stars via three-body scattering, but ample work has shown that in spherical galaxy models, the binary separation stalls after ejecting all the stars in its loss cone—this is the well-known final parsec problem. However, it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in both corotating and counterrotating flattened galaxy models. For N > 500 K, we find that the evolution of the SMBH binary is convergent and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co- and counterrotating galaxies. In the corotating case, the center of mass of the SMBH binary settles into an orbit that is in corotation resonance with the background rotating model, and the coalescence time is roughly a few 100 Myr faster than a non-rotating flattened model. We find that counterrotation drives SMBHs to coalesce on a nearly radial orbit promptly after forming a hard binary. We discuss the implications for gravitational wave astronomy, hypervelocity star production, and the effect on the structure of the host galaxy.

GALAXY ROTATION AND RAPID SUPERMASSIVE BINARY COALESCENCE

International Nuclear Information System (INIS)

Holley-Bockelmann, Kelly; Khan, Fazeel Mahmood

2015-01-01

Galaxy mergers usher the supermassive black hole (SMBH) in each galaxy to the center of the potential, where they form an SMBH binary. The binary orbit shrinks by ejecting stars via three-body scattering, but ample work has shown that in spherical galaxy models, the binary separation stalls after ejecting all the stars in its loss cone—this is the well-known final parsec problem. However, it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in both corotating and counterrotating flattened galaxy models. For N > 500 K, we find that the evolution of the SMBH binary is convergent and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co- and counterrotating galaxies. In the corotating case, the center of mass of the SMBH binary settles into an orbit that is in corotation resonance with the background rotating model, and the coalescence time is roughly a few 100 Myr faster than a non-rotating flattened model. We find that counterrotation drives SMBHs to coalesce on a nearly radial orbit promptly after forming a hard binary. We discuss the implications for gravitational wave astronomy, hypervelocity star production, and the effect on the structure of the host galaxy

Hidden slow pulsars in binaries

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Tavani, Marco; Brookshaw, Leigh

1993-01-01

The recent discovery of the binary containing the slow pulsar PSR 1718-19 orbiting around a low-mass companion star adds new light on the characteristics of binary pulsars. The properties of the radio eclipses of PSR 1718-19 are the most striking observational characteristics of this system. The surface of the companion star produces a mass outflow which leaves only a small 'window' in orbital phase for the detection of PSR 1718-19 around 400 MHz. At this observing frequency, PSR 1718-19 is clearly observable only for about 1 hr out of the total 6.2 hr orbital period. The aim of this Letter is twofold: (1) to model the hydrodynamical behavior of the eclipsing material from the companion star of PSR 1718-19 and (2) to argue that a population of binary slow pulsars might have escaped detection in pulsar surveys carried out at 400 MHz. The possible existence of a population of partially or totally hidden slow pulsars in binaries will have a strong impact on current theories of binary evolution of neutron stars.

Zeta potentials in the flotation of oxide and silicate minerals.

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Fuerstenau, D W; Pradip

2005-06-30

Adsorption of collectors and modifying reagents in the flotation of oxide and silicate minerals is controlled by the electrical double layer at the mineral-water interface. In systems where the collector is physically adsorbed, flotation with anionic or cationic collectors depends on the mineral surface being charged oppositely. Adjusting the pH of the system can enhance or prevent the flotation of a mineral. Thus, the point of zero charge (PZC) of the mineral is the most important property of a mineral in such systems. The length of the hydrocarbon chain of the collector is important because of chain-chain association enhances the adsorption once the surfactant ions aggregate to form hemimicelles at the surface. Strongly chemisorbing collectors are able to induce flotation even when collector and the mineral surface are charged similarly, but raising the pH sufficiently above the PZC can repel chemisorbing collectors from the mineral surface. Zeta potentials can be used to delineate interfacial phenomena in these various systems.

Perceptual biases for rhythm: The Mismatch Negativity latency indexes the privileged status of binary vs non-binary interval ratios.

Science.gov (United States)

Pablos Martin, X; Deltenre, P; Hoonhorst, I; Markessis, E; Rossion, B; Colin, C

2007-12-01

Rhythm perception appears to be non-linear as human subjects are better at discriminating, categorizing and reproducing rhythms containing binary vs non-binary (e.a. 1:2 vs 1:3) as well as metrical vs non-metrical (e.a. 1:2 vs 1:2.5) interval ratios. This study examined the representation of binary and non-binary interval ratios within the sensory memory, thus yielding a truly sensory, pre-motor, attention-independent neural representation of rhythmical intervals. Five interval ratios, one binary, flanked by four non-binary ones, were compared on the basis of the MMN they evoked when contrasted against a common standard interval. For all five intervals, the larger the contrast was, the larger the MMN amplitude was. The binary interval evoked a significantly much shorter (by at least 23 ms) MMN latency than the other intervals, whereas no latency difference was observed between the four non-binary intervals. These results show that the privileged perceptual status of binary rhythmical intervals is already present in the sensory representations found in echoic memory at an early, automatic, pre-perceptual and pre-motor level. MMN latency can be used to study rhythm perception at a truly sensory level, without any contribution from the motor system.

SECULAR EVOLUTION OF BINARIES NEAR MASSIVE BLACK HOLES: FORMATION OF COMPACT BINARIES, MERGER/COLLISION PRODUCTS AND G2-LIKE OBJECTS

International Nuclear Information System (INIS)

Prodan, Snezana; Antonini, Fabio; Perets, Hagai B.

2015-01-01

Here we discuss the evolution of binaries around massive black holes (MBHs) in nuclear stellar clusters. We focus on their secular evolution due to the perturbation by the MBHs, while simplistically accounting for their collisional evolution. Binaries with highly inclined orbits with respect to their orbits around MBHs are strongly affected by secular processes, which periodically change their eccentricities and inclinations (e.g., Kozai-Lidov cycles). During periapsis approach, dissipative processes such as tidal friction may become highly efficient, and may lead to shrinkage of a binary orbit and even to its merger. Binaries in this environment can therefore significantly change their orbital evolution due to the MBH third-body perturbative effects. Such orbital evolution may impinge on their later stellar evolution. Here we follow the secular dynamics of such binaries and its coupling to tidal evolution, as well as the stellar evolution of such binaries on longer timescales. We find that stellar binaries in the central parts of nuclear stellar clusters (NSCs) are highly likely to evolve into eccentric and/or short-period binaries, and become strongly interacting binaries either on the main sequence (at which point they may even merge), or through their later binary stellar evolution. The central parts of NSCs therefore catalyze the formation and evolution of strongly interacting binaries, and lead to the enhanced formation of blue stragglers, X-ray binaries, gravitational wave sources, and possible supernova progenitors. Induced mergers/collisions may also lead to the formation of G2-like cloud-like objects such as the one recently observed in the Galactic center

Evolution of dwarf binaries

International Nuclear Information System (INIS)

Tutukov, A.V.; Fedorova, A.V.; Yungel'son, L.R.

1982-01-01

The conditions of mass exchange in close binary systems with masses of components less or equal to one solar mass have been analysed for the case, when the system radiates gravitational waves. It has been shown that the mass exchange rate depends in a certain way on the mass ratio of components and on the mass of component that fills its inner critical lobe. The comparison of observed periods, masses of contact components, and mass exchange rates of observed cataclysmic binaries have led to the conclusion that the evolution of close binaries WZ Sge, OY Car, Z Cha, TT Ari, 2A 0311-227, and G 61-29 may be driven by the emission of gravitational waves [ru

Massive binaries in the vicinity of Sgr A*

Energy Technology Data Exchange (ETDEWEB)

Pfuhl, O.; Gillessen, S.; Genzel, R.; Eisenhauer, F.; Fritz, T. K.; Ott, T. [Max-Planck-Institut für Extraterrestrische Physik, D-85748 Garching (Germany); Alexander, T. [Faculty of Physics, Weizmann Institute of Science, P.O. Box 26, Rehovot 76100 (Israel); Martins, F., E-mail: pfuhl@mpe.mpg.de [LUPM, Université Montpelier 2, CNRS, Place Eugéne Bataillon, F-34095, Montpellier (France)

2014-02-20

A long-term spectroscopic and photometric survey of the most luminous and massive stars in the vicinity of the supermassive black hole Sgr A* revealed two new binaries: a long-period Ofpe/WN9 binary, IRS 16NE, with a modest eccentricity of 0.3 and a period of 224 days, and an eclipsing Wolf-Rayet binary with a period of 2.3 days. Together with the already identified binary IRS 16SW, there are now three confirmed OB/WR binaries in the inner 0.2 pc of the Galactic center. Using radial velocity change upper limits, we were able to constrain the spectroscopic binary fraction in the Galactic center to F{sub SB}=0.30{sub −0.21}{sup +0.34} at a confidence level of 95%, a massive binary fraction close to that observed in dense clusters. The fraction of eclipsing binaries with photometric amplitudes Δm > 0.4 is F{sub EB}{sup GC}=3%±2%, which is consistent with local OB star clusters (F {sub EB} = 1%). Overall, the Galactic center binary fraction seems to be similar to the binary fraction in comparable young clusters.

EVOLUTION OF THE BINARY FRACTION IN DENSE STELLAR SYSTEMS

International Nuclear Information System (INIS)

Fregeau, John M.; Ivanova, Natalia; Rasio, Frederic A.

2009-01-01

Using our recently improved Monte Carlo evolution code, we study the evolution of the binary fraction in globular clusters. In agreement with previous N-body simulations, we find generally that the hard binary fraction in the core tends to increase with time over a range of initial cluster central densities for initial binary fractions ∼<90%. The dominant processes driving the evolution of the core binary fraction are mass segregation of binaries into the cluster core and preferential destruction of binaries there. On a global scale, these effects and the preferential tidal stripping of single stars tend to roughly balance, leading to overall cluster binary fractions that are roughly constant with time. Our findings suggest that the current hard binary fraction near the half-mass radius is a good indicator of the hard primordial binary fraction. However, the relationship between the true binary fraction and the fraction of main-sequence stars in binaries (which is typically what observers measure) is nonlinear and rather complicated. We also consider the importance of soft binaries, which not only modify the evolution of the binary fraction, but can also drastically change the evolution of the cluster as a whole. Finally, we briefly describe the recent addition of single and binary stellar evolution to our cluster evolution code.

Activity coefficients of solutes in binary solvents

International Nuclear Information System (INIS)

Gokcen, N.A.

1982-01-01

The activity coefficients in dilute ternary systems are discussed in detail by using the Margules equations. Analyses of some relevant data at high temperatures show that the sparingly dissolved solutes in binary solvents follow complex behavior even when the binary solvents are very nearly ideal. It is shown that the activity data on the solute or the binary system cannot permit computation of the remaining activities except for the regular solutions. It is also shown that a fourth-order equation is usually adequate in expressing the activity coefficient of a solute in binary solvents at high temperatures. When the activity data for a binary solvent are difficult to obtain in a certain range of composition, the activity data for a sparingly dissolved solute can be used to supplement determination of the binary activities

All-optical conversion scheme: Binary to quaternary and quaternary to binary number

Science.gov (United States)

Chattopadhyay, Tanay; Roy, Jitendra Nath

2009-04-01

To achieve the inherent parallelism in optics a suitable number system and efficient encoding/decoding scheme for handling the data are very much essential. Binary number is accepted as the best representing number system in almost all types of existing electronic computers. But, binary number (0 and 1) is insufficient in respect to the demand of the coming generation. Multi-valued logic (with radix >2) can be viewed as an alternative approach to solve many problems in transmission, storage and processing of large amount of information in digital signal processing. Here, in this paper all-optical scheme for the conversion of binary to quaternary number and vice versa have been proposed and described. Simulation has also been done. In this all-optical scheme the numbers are represented by different discrete polarized state of light.

Hearing the music of the primes: auditory complementarity and the siren song of zeta

International Nuclear Information System (INIS)

Berry, M V

2012-01-01

A counting function for the primes can be rendered as a sound signal whose harmonies, spanning the gamut of musical notes, are the Riemann zeros. But the individual primes cannot be discriminated as singularities in this ‘music’, because the intervals between them are too short. Conversely, if the prime singularities are detected as a series of clicks, the Riemann zeros correspond to frequencies too low to be heard. The sound generated by the Riemann zeta function itself is very different: a rising siren howl, which can be understood in detail from the Riemann–Siegel formula. (fast track communication)

COSMIC probes into compact binary formation and evolution

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Breivik, Katelyn

2018-01-01

The population of compact binaries in the galaxy represents the final state of all binaries that have lived up to the present epoch. Compact binaries present a unique opportunity to probe binary evolution since many of the interactions binaries experience can be imprinted on the compact binary population. By combining binary evolution simulations with catalogs of observable compact binary systems, we can distill the dominant physical processes that govern binary star evolution, as well as predict the abundance and variety of their end products.The next decades herald a previously unseen opportunity to study compact binaries. Multi-messenger observations from telescopes across all wavelengths and gravitational-wave observatories spanning several decades of frequency will give an unprecedented view into the structure of these systems and the composition of their components. Observations will not always be coincident and in some cases may be separated by several years, providing an avenue for simulations to better constrain binary evolution models in preparation for future observations.I will present the results of three population synthesis studies of compact binary populations carried out with the Compact Object Synthesis and Monte Carlo Investigation Code (COSMIC). I will first show how binary-black-hole formation channels can be understood with LISA observations. I will then show how the population of double white dwarfs observed with LISA and Gaia could provide a detailed view of mass transfer and accretion. Finally, I will show that Gaia could discover thousands black holes in the Milky Way through astrometric observations, yielding view into black-hole astrophysics that is complementary to and independent from both X-ray and gravitational-wave astronomy.

Binary versus non-binary information in real time series: empirical results and maximum-entropy matrix models

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Almog, Assaf; Garlaschelli, Diego

2014-09-01

The dynamics of complex systems, from financial markets to the brain, can be monitored in terms of multiple time series of activity of the constituent units, such as stocks or neurons, respectively. While the main focus of time series analysis is on the magnitude of temporal increments, a significant piece of information is encoded into the binary projection (i.e. the sign) of such increments. In this paper we provide further evidence of this by showing strong nonlinear relations between binary and non-binary properties of financial time series. These relations are a novel quantification of the fact that extreme price increments occur more often when most stocks move in the same direction. We then introduce an information-theoretic approach to the analysis of the binary signature of single and multiple time series. Through the definition of maximum-entropy ensembles of binary matrices and their mapping to spin models in statistical physics, we quantify the information encoded into the simplest binary properties of real time series and identify the most informative property given a set of measurements. Our formalism is able to accurately replicate, and mathematically characterize, the observed binary/non-binary relations. We also obtain a phase diagram allowing us to identify, based only on the instantaneous aggregate return of a set of multiple time series, a regime where the so-called ‘market mode’ has an optimal interpretation in terms of collective (endogenous) effects, a regime where it is parsimoniously explained by pure noise, and a regime where it can be regarded as a combination of endogenous and exogenous factors. Our approach allows us to connect spin models, simple stochastic processes, and ensembles of time series inferred from partial information.

Binary versus non-binary information in real time series: empirical results and maximum-entropy matrix models

International Nuclear Information System (INIS)

Almog, Assaf; Garlaschelli, Diego

2014-01-01

The dynamics of complex systems, from financial markets to the brain, can be monitored in terms of multiple time series of activity of the constituent units, such as stocks or neurons, respectively. While the main focus of time series analysis is on the magnitude of temporal increments, a significant piece of information is encoded into the binary projection (i.e. the sign) of such increments. In this paper we provide further evidence of this by showing strong nonlinear relations between binary and non-binary properties of financial time series. These relations are a novel quantification of the fact that extreme price increments occur more often when most stocks move in the same direction. We then introduce an information-theoretic approach to the analysis of the binary signature of single and multiple time series. Through the definition of maximum-entropy ensembles of binary matrices and their mapping to spin models in statistical physics, we quantify the information encoded into the simplest binary properties of real time series and identify the most informative property given a set of measurements. Our formalism is able to accurately replicate, and mathematically characterize, the observed binary/non-binary relations. We also obtain a phase diagram allowing us to identify, based only on the instantaneous aggregate return of a set of multiple time series, a regime where the so-called ‘market mode’ has an optimal interpretation in terms of collective (endogenous) effects, a regime where it is parsimoniously explained by pure noise, and a regime where it can be regarded as a combination of endogenous and exogenous factors. Our approach allows us to connect spin models, simple stochastic processes, and ensembles of time series inferred from partial information. (paper)

PERIODIC SIGNALS IN BINARY MICROLENSING EVENTS

International Nuclear Information System (INIS)

Guo, Xinyi; Stefano, Rosanne Di; Esin, Ann; Taylor, Jeffrey

2015-01-01

Gravitational microlensing events are powerful tools for the study of stellar populations. In particular, they can be used to discover and study a variety of binary systems. A large number of binary lenses have already been found through microlensing surveys and a few of these systems show strong evidence of orbital motion on the timescale of the lensing event. We expect that more binary lenses of this kind will be detected in the future. For binaries whose orbital period is comparable to the event duration, the orbital motion can cause the lensing signal to deviate drastically from that of a static binary lens. The most striking property of such light curves is the presence of quasi-periodic features, which are produced as the source traverses the same regions in the rotating lens plane. These repeating features contain information about the orbital period of the lens. If this period can be extracted, then much can be learned about the lensing system even without performing time-consuming, detailed light-curve modeling. However, the relative transverse motion between the source and the lens significantly complicates the problem of period extraction. To resolve this difficulty, we present a modification of the standard Lomb–Scargle periodogram analysis. We test our method for four representative binary lens systems and demonstrate its efficiency in correctly extracting binary orbital periods

Improving geothermal power plants with a binary cycle

Science.gov (United States)

Tomarov, G. V.; Shipkov, A. A.; Sorokina, E. V.

2015-12-01

The recent development of binary geothermal technology is analyzed. General trends in the introduction of low-temperature geothermal sources are summarized. The use of single-phase low-temperature geothermal fluids in binary power plants proves possible and expedient. The benefits of power plants with a binary cycle in comparison with traditional systems are shown. The selection of the working fluid is considered, and the influence of the fluid's physicochemical properties on the design of the binary power plant is discussed. The design of binary power plants is based on the chemical composition and energy potential of the geothermal fluids and on the landscape and climatic conditions at the intended location. Experience in developing a prototype 2.5 MW Russian binary power unit at Pauzhetka geothermal power plant (Kamchatka) is outlined. Most binary systems are designed individually for a specific location. Means of improving the technology and equipment at binary geothermal power plants are identified. One option is the development of modular systems based on several binary systems that employ the heat from the working fluid at different temperatures.

THE EVOLVED MAIN-SEQUENCE CHANNEL: HST AND LBT OBSERVATIONS OF CSS 120422:111127+571239

Energy Technology Data Exchange (ETDEWEB)

Kennedy, M.; Callanan, P. [Department of Physics, University College Cork, Cork (Ireland); Garnavich, P.; Littlefield, C. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Szkody, P. [Department of Astronomy, University of Washington, Seattle, WA (United States); Pogge, R. [Department of Astronomy, The Ohio State University, 140 W. 18th Avenue, Columbus, OH 43202 (United States)

2015-12-20

The “evolved main-sequence (EMS)” channel is thought to contribute significantly to the population of AM CVn-type systems in the Galaxy, and also to the number of cataclysmic variables (CVs) detected below the period minimum for hydrogen rich systems. CSS 120422:J111127+571239 was discovered by the Catalina Sky Survey in 2012 April. Its period was found to be 56 minutes, well below the minimum, and the optical spectrum is clearly depleted in hydrogen relative to helium, but still has two orders of magnitude more hydrogen than AM CVn stars. Doppler tomography of the Hα line hinted at a spiral structure existing in the disk. Here we present spectroscopy of CSS 120422:J111127+571239 using the Cosmic Origins Spectrograph FUV instrument on the Hubble Space Telescope and using the MODS spectrograph on the Large Binocular Telescope. The UV spectrum shows Si iv, N v, and He ii, but no detectable C iv. The anomalous nitrogen/carbon ratio is seen in a small number of other CVs and confirms a unique binary evolution. We also present and compare the optical spectrum of V418 Ser and advocate that it is also an EMS system.

Topological and categorical properties of binary trees

Directory of Open Access Journals (Sweden)

H. Pajoohesh

2008-04-01

Full Text Available Binary trees are very useful tools in computer science for estimating the running time of so-called comparison based algorithms, algorithms in which every action is ultimately based on a prior comparison between two elements. For two given algorithms A and B where the decision tree of A is more balanced than that of B, it is known that the average and worst case times of A will be better than those of B, i.e., ₸A(n ≤₸B(n and TWA (n≤TWB (n. Thus the most balanced and the most imbalanced binary trees play a main role. Here we consider them as semilattices and characterize the most balanced and the most imbalanced binary trees by topological and categorical properties. Also we define the composition of binary trees as a commutative binary operation, *, such that for binary trees A and B, A * B is the binary tree obtained by attaching a copy of B to any leaf of A. We show that (T,* is a commutative po-monoid and investigate its properties.

Optimally cloned binary coherent states

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Müller, C. R.; Leuchs, G.; Marquardt, Ch.; Andersen, U. L.

2017-10-01

Binary coherent state alphabets can be represented in a two-dimensional Hilbert space. We capitalize this formal connection between the otherwise distinct domains of qubits and continuous variable states to map binary phase-shift keyed coherent states onto the Bloch sphere and to derive their quantum-optimal clones. We analyze the Wigner function and the cumulants of the clones, and we conclude that optimal cloning of binary coherent states requires a nonlinearity above second order. We propose several practical and near-optimal cloning schemes and compare their cloning fidelity to the optimal cloner.

Binaries and triples among asteroid pairs

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Pravec, Petr; Scheirich, Peter; Kušnirák, Peter; Hornoch, Kamil; Galád, Adrián

2015-08-01

Despite major achievements obtained during the past two decades, our knowledge of the population and properties of small binary and multiple asteroid systems is still far from advanced. There is a numerous indirect evidence for that most small asteroid systems were formed by rotational fission of cohesionless parent asteroids that were spun up to the critical frequency presumably by YORP, but details of the process are lacking. Furthermore, as we proceed with observations of more and more binary and paired asteroids, we reveal new facts that substantially refine and sometimes change our understanding of the asteroid systems. One significant new finding we have recently obtained is that primaries of many asteroid pairs are actually binary or triple systems. The first such case found is (3749) Balam (Vokrouhlický, ApJL 706, L37, 2009). We have found 9 more binary systems among asteroid pairs within our ongoing NEOSource photometric project since October 2012. They are (6369) 1983 UC, (8306) Shoko, (9783) Tensho-kan, (10123) Fideoja, (21436) Chaoyichi, (43008) 1999 UD31, (44620) 1999 RS43, (46829) 1998 OS14 and (80218) 1999 VO123. We will review their characteristics. These paired binaries as we call them are mostly similar to binaries in the general ("background") population (of unpaired asteroids), but there are a few trends. The paired binaries tend to have larger secondaries with D_2/D_1 = 0.3 to 0.5 and they also tend to be wider systems with 8 of the 10 having orbital periods between 30 and 81 hours, than average among binaries in the general population. There may be also a larger fraction of triples; (3749) Balam is a confirmed triple, having a larger close and a smaller distant satellite, and (8306) Shoko and (10123) Fideoja are suspect triples as they show additional rotational lightcurve components with periods of 61 and 38.8 h that differ from the orbital period of 36.2 and 56.5 h, respectively. The unbound secondaries tend to be of the same size or

Detecting Malicious Code by Binary File Checking

Directory of Open Access Journals (Sweden)

Marius POPA

2014-01-01

Full Text Available The object, library and executable code is stored in binary files. Functionality of a binary file is altered when its content or program source code is changed, causing undesired effects. A direct content change is possible when the intruder knows the structural information of the binary file. The paper describes the structural properties of the binary object files, how the content can be controlled by a possible intruder and what the ways to identify malicious code in such kind of files. Because the object files are inputs in linking processes, early detection of the malicious content is crucial to avoid infection of the binary executable files.

Mass Transfer in Mira-Type Binaries

Directory of Open Access Journals (Sweden)

Mohamed S.

2012-06-01

Full Text Available Detached, symbiotic binaries are generally assumed to interact via Bondi-Hoyle-Littleton (BHL wind accretion. However, the accretion rates and outflow geometries that result from this mass-transfer mechanism cannot adequately explain the observations of the nearest and best studied symbiotic binary, Mira, or the formation of some post-AGB binaries, e.g. barium stars. We propose a new mass-transfer mode for Mira-type binaries, which we call ‘wind Roche-lobe overflow’ (WRLOF, and which we demonstrate with 3D hydrodynamic simulations. Importantly, we show that the circumstellar outflows which result from WRLOF tend to be highly aspherical and strongly focused towards the binary orbital plane. Furthermore, the subsequent mass-transfer rates are at least an order of magnitude greater than the analogous BHL values. We discuss the implications of these results for the shaping of bipolar (proto-planetary nebulae and other related systems.

New O-C Observations for 150 Algols: Insight to the Origins of Period Shifts

Science.gov (United States)

Hoffman, D. I.; Harrison, T. E.; McNamara, B. J.; Vestrand, W. T.

2005-12-01

Many eclipsing binaries of type Algol, RS CVn, and W UMa have observed orbital period shifts. Of these, many show both increasing and decreasing period shifts. Two leading explanations for these shifts are third body effects and magnetic activity changing the oblateness of the secondary, though neither one can explain all of the observed period oscillations. The first-generation Robotic Optical Transient Search Experiment (ROTSE-I) based in Los Alamos, NM, was primarily designed to look for the optical counterparts to gamma-ray bursts as well as searching for other optical transients not detected in gamma-rays. The telescope, consisting of four 200mm camera lenses, can image the entire northern sky twice in a night, which is a very useful tool in monitoring relatively bright eclipsing binaries for period shifts. The public data release from ROTSE-I, the Northern Sky Variability Survey (NSVS), spans one year of data stating in April, 1999. O-C data for 150 eclipsing binaries are presented using the NSVS data. We revisit work by Borkovits and Hegedüs on some third body candidates in several eclipsing binary systems using recent AAVSO and NSVS data. Some unusual light curves of eclipsing binaries produced from NSVS data is presented and discussed.

Microlensing Signature of Binary Black Holes

Science.gov (United States)

Schnittman, Jeremy; Sahu, Kailash; Littenberg, Tyson

2012-01-01

We calculate the light curves of galactic bulge stars magnified via microlensing by stellar-mass binary black holes along the line-of-sight. We show the sensitivity to measuring various lens parameters for a range of survey cadences and photometric precision. Using public data from the OGLE collaboration, we identify two candidates for massive binary systems, and discuss implications for theories of star formation and binary evolution.

Formation and Evolution of X-ray Binaries

Science.gov (United States)

Fragkos, Anastasios

X-ray binaries - mass-transferring binary stellar systems with compact object accretors - are unique astrophysical laboratories. They carry information about many complex physical processes such as star formation, compact object formation, and evolution of interacting binaries. My thesis work involves the study of the formation and evolution of Galactic and extra-galacticX-ray binaries using both detailed and realistic simulation tools, and population synthesis techniques. I applied an innovative analysis method that allows the reconstruction of the full evolutionary history of known black hole X-ray binaries back to the time of compact object formation. This analysis takes into account all the available observationally determined properties of a system, and models in detail four of its evolutionary evolutionary phases: mass transfer through the ongoing X-ray phase, tidal evolution before the onset of Roche-lobe overflow, motion through the Galactic potential after the formation of the black hole, and binary orbital dynamics at the time of core collapse. Motivated by deep extra-galactic Chandra survey observations, I worked on population synthesis models of low-mass X-ray binaries in the two elliptical galaxies NGC3379 and NGC4278. These simulations were targeted at understanding the origin of the shape and normalization of the observed X-ray luminosity functions. In a follow up study, I proposed a physically motivated prescription for the modeling of transient neutron star low-mass X-ray binary properties, such as duty cycle, outburst duration and recurrence time. This prescription enabled the direct comparison of transient low-mass X-ray binary population synthesis models to the Chandra X-ray survey of the two ellipticals NGC3379 and NGC4278. Finally, I worked on population synthesismodels of black holeX-ray binaries in the MilkyWay. This work was motivated by recent developments in observational techniques for the measurement of black hole spin magnitudes in

Detectability of Gravitational Waves from High-Redshift Binaries.

Science.gov (United States)

Rosado, Pablo A; Lasky, Paul D; Thrane, Eric; Zhu, Xingjiang; Mandel, Ilya; Sesana, Alberto

2016-03-11

Recent nondetection of gravitational-wave backgrounds from pulsar timing arrays casts further uncertainty on the evolution of supermassive black hole binaries. We study the capabilities of current gravitational-wave observatories to detect individual binaries and demonstrate that, contrary to conventional wisdom, some are, in principle, detectable throughout the Universe. In particular, a binary with rest-frame mass ≳10^{10}M_{⊙} can be detected by current timing arrays at arbitrarily high redshifts. The same claim will apply for less massive binaries with more sensitive future arrays. As a consequence, future searches for nanohertz gravitational waves could be expanded to target evolving high-redshift binaries. We calculate the maximum distance at which binaries can be observed with pulsar timing arrays and other detectors, properly accounting for redshift and using realistic binary waveforms.

Investigation of the Interaction Between Human Serum Albumin and Two Drugs as Binary and Ternary Systems.

Science.gov (United States)

Abdollahpour, Nooshin; Soheili, Vahid; Saberi, Mohammad Reza; Chamani, Jamshidkhan

2016-12-01

Human serum albumin (HSA) is the most frequent protein in blood plasma. Albumin transports various compounds, preserves osmotic pressure, and buffers pH. A unique feature of albumin is its ability to bind drugs and other bioactive molecules. However, it is important to consider binary and ternary systems of two pharmaceuticals to estimate the effect of the first drug on the second one and physicochemical properties. Different techniques including time-resolved, second-derivative and anisotropy fluorescence spectroscopy, resonance light scattering (RLS), critical induced aggregation concentration (C CIAC ), particle size, zeta potential and stability analysis were employed in this assessment to elucidate the binding behavior of Amlodipine and Aspirin to HSA. Moreover, isothermal titration calorimetric techniques were performed and the QSAR properties were applied to analyze the hydration energy and log P. Multiple sequence alignments were also used to predict the structure and biological characteristics of the HSA binding site. Time-resolved fluorescence spectroscopy showed interaction of both drugs to HSA based on a static quenching mechanism. Subsequently, second-derivative fluorescence spectroscopy presented different values of parameter H in binary and ternary systems, which were suggested that tryptophan was in a more polar environment in the ternary system than in a binary system. Moreover, the polydispersity index and results from mean number measurements revealed that the presence of the second drug caused a decrease in the stability of systems and increased the heterogeneity of complex. It is also, observed that the gradual addition of HSA has led to a marked increase in fluorescence anisotropy (r) of Amlodipine and Aspirin which can be suggested that the drugs were located in a restricted environment of the protein as confirmed by Red Edge Excitation Shift (REES) studies. The isothermal titration calorimetric technique demonstrated that the interaction of

Generation of nanobubbles by ceramic membrane filters: The dependence of bubble size and zeta potential on surface coating, pore size and injected gas pressure.

Science.gov (United States)

Ahmed, Ahmed Khaled Abdella; Sun, Cuizhen; Hua, Likun; Zhang, Zhibin; Zhang, Yanhao; Zhang, Wen; Marhaba, Taha

2018-07-01

Generation of gaseous nanobubbles (NBs) by simple, efficient, and scalable methods is critical for industrialization and applications of nanobubbles. Traditional generation methods mainly rely on hydrodynamic, acoustic, particle, and optical cavitation. These generation processes render issues such as high energy consumption, non-flexibility, and complexity. This research investigated the use of tubular ceramic nanofiltration membranes to generate NBs in water with air, nitrogen and oxygen gases. This system injects pressurized gases through a tubular ceramic membrane with nanopores to create NBs. The effects of membrane pores size, surface energy, and the injected gas pressures on the bubble size and zeta potential were examined. The results show that the gas injection pressure had considerable effects on the bubble size, zeta potential, pH, and dissolved oxygen of the produced NBs. For example, increasing the injection air pressure from 69 kPa to 414 kPa, the air bubble size was reduced from 600 to 340 nm respectively. Membrane pores size and surface energy also had significant effects on sizes and zeta potentials of NBs. The results presented here aim to fill out the gaps of fundamental knowledge about NBs and development of efficient generation methods. Copyright © 2018 Elsevier Ltd. All rights reserved.

Non-binary Entanglement-assisted Stabilizer Quantum Codes

OpenAIRE

Riguang, Leng; Zhi, Ma

2011-01-01

In this paper, we show how to construct non-binary entanglement-assisted stabilizer quantum codes by using pre-shared entanglement between the sender and receiver. We also give an algorithm to determine the circuit for non-binary entanglement-assisted stabilizer quantum codes and some illustrated examples. The codes we constructed do not require the dual-containing constraint, and many non-binary classical codes, like non-binary LDPC codes, which do not satisfy the condition, can be used to c...

Improving the Efficiency of a Coagulation-Flocculation Wastewater Treatment of the Semiconductor Industry through Zeta Potential Measurements

Directory of Open Access Journals (Sweden)

Eduardo Alberto López-Maldonado

2014-01-01

Full Text Available Efficiency of coagulation-flocculation process used for semiconductor wastewater treatment was improved by selecting suitable conditions (pH, polyelectrolyte type, and concentration through zeta potential measurements. Under this scenario the zeta potential, ζ, is the right parameter that allows studying and predicting the interactions at the molecular level between the contaminants in the wastewater and polyelectrolytes used for coagulation-flocculation. Additionally, this parameter is a key factor for assessing the efficiency of coagulation-flocculation processes based on the optimum dosages and windows for polyelectrolytes coagulation-flocculation effectiveness. In this paper, strategic pH variations allowed the prediction of the dosage of polyelectrolyte on wastewater from real electroplating baths, including the isoelectric point (IEP of the dispersions of water and commercial polyelectrolytes used in typical semiconductor industries. The results showed that there is a difference between polyelectrolyte demand required for the removal of suspended solids, turbidity, and organic matter from wastewater (23.4 mg/L and 67 mg/L, resp.. It was also concluded that the dose of polyelectrolytes and coagulation-flocculation window to achieve compliance with national and international regulations as EPA in USA and SEMARNAT in Mexico is influenced by the physicochemical characteristics of the dispersions and treatment conditions (pH and polyelectrolyte dosing strategy.

Mesoscopic model for binary fluids

Science.gov (United States)

Echeverria, C.; Tucci, K.; Alvarez-Llamoza, O.; Orozco-Guillén, E. E.; Morales, M.; Cosenza, M. G.

2017-10-01

We propose a model for studying binary fluids based on the mesoscopic molecular simulation technique known as multiparticle collision, where the space and state variables are continuous, and time is discrete. We include a repulsion rule to simulate segregation processes that does not require calculation of the interaction forces between particles, so binary fluids can be described on a mesoscopic scale. The model is conceptually simple and computationally efficient; it maintains Galilean invariance and conserves the mass and energy in the system at the micro- and macro-scale, whereas momentum is conserved globally. For a wide range of temperatures and densities, the model yields results in good agreement with the known properties of binary fluids, such as the density profile, interface width, phase separation, and phase growth. We also apply the model to the study of binary fluids in crowded environments with consistent results.

Kepler eclipsing binary stars. IV. Precise eclipse times for close binaries and identification of candidate three-body systems

International Nuclear Information System (INIS)

Conroy, Kyle E.; Stassun, Keivan G.; Prša, Andrej; Orosz, Jerome A.; Welsh, William F.; Fabrycky, Daniel C.

2014-01-01

We present a catalog of precise eclipse times and analysis of third-body signals among 1279 close binaries in the latest Kepler Eclipsing Binary Catalog. For these short-period binaries, Kepler's 30 minute exposure time causes significant smearing of light curves. In addition, common astrophysical phenomena such as chromospheric activity, as well as imperfections in the light curve detrending process, can create systematic artifacts that may produce fictitious signals in the eclipse timings. We present a method to measure precise eclipse times in the presence of distorted light curves, such as in contact and near-contact binaries which exhibit continuously changing light levels in and out of eclipse. We identify 236 systems for which we find a timing variation signal compatible with the presence of a third body. These are modeled for the light travel time effect and the basic properties of the third body are derived. This study complements J. A. Orosz et al. (in preparation), which focuses on eclipse timing variations of longer period binaries with flat out-of-eclipse regions. Together, these two papers provide comprehensive eclipse timings for all binaries in the Kepler Eclipsing Binary Catalog, as an ongoing resource freely accessible online to the community.

CIRCUMBINARY MAGNETOHYDRODYNAMIC ACCRETION INTO INSPIRALING BINARY BLACK HOLES

Energy Technology Data Exchange (ETDEWEB)

Noble, Scott C.; Mundim, Bruno C.; Nakano, Hiroyuki; Campanelli, Manuela; Zlochower, Yosef [Center for Computational Relativity and Gravitation, Rochester Institute of Technology, Rochester, NY 14623 (United States); Krolik, Julian H. [Physics and Astronomy Department, Johns Hopkins University, Baltimore, MD 21218 (United States); Yunes, Nicolas, E-mail: scn@astro.rit.edu [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

2012-08-10

We have simulated the magnetohydrodynamic evolution of a circumbinary disk surrounding an equal-mass binary comprising two non-spinning black holes during the period in which the disk inflow time is comparable to the binary evolution time due to gravitational radiation. Both the changing spacetime and the binary orbital evolution are described by an innovative technique utilizing high-order post-Newtonian approximations. Prior to the beginning of the inspiral, the structure of the circumbinary disk is predicted well by extrapolation from Newtonian results: a gap of roughly two binary separation radii is cleared, and matter piles up at the outer edge of this gap as inflow is retarded by torques exerted by the binary; the accretion rate is roughly half its value at large radius. During inspiral, the inner edge of the disk initially moves inward in coordination with the shrinking binary, but-as the orbital evolution accelerates-the inward motion of the disk edge falls behind the rate of binary compression. In this stage, the binary torque falls substantially, but the accretion rate decreases by only 10%-20%. When the binary separation is tens of gravitational radii, the rest-mass efficiency of disk radiation is a few percent, suggesting that supermassive binary black holes could be very luminous at this stage of their evolution. Inner disk heating is modulated at a beat frequency comparable to the binary orbital frequency. However, a disk with sufficient surface density to be luminous may be optically thick, suppressing periodic modulation of the luminosity.

Binary and Millisecond Pulsars

Directory of Open Access Journals (Sweden)

Lorimer Duncan R.

2008-11-01

Full Text Available We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1800. There are now 83 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 140 pulsars in 26 of the Galactic globular clusters. Recent highlights include the discovery of the young relativistic binary system PSR J1906+0746, a rejuvination in globular cluster pulsar research including growing numbers of pulsars with masses in excess of 1.5M_⊙, a precise measurement of relativistic spin precession in the double pulsar system and a Galactic millisecond pulsar in an eccentric (e = 0.44 orbit around an unevolved companion.

Observations of new Wolf-Rayet binaries

International Nuclear Information System (INIS)

Niemela, V.S.

1982-01-01

The author reports here preliminary results of spectrographic observations for three southern WR stars, whose binary nature had not been previously verified: HDE 320102, CD -45 0 4482, HD 62910. The observations were carried out at the Cerro Tololo Inter-American Observatory, Chile, mostly with the Cassegrain spectrograph with IT attached to the 1-m reflector. These spectrograms were secured on Kodak IIIaJ emulsion, and have a dispersion of 45 A/mm. The results suggest that HDE 320102 must be a double-lined 05-7 + WN3 spectroscopic binary, that CD -45 0 4482 appears to be a single-lined spectroscopic binary and that HD 62910 may be a binary. (Auth.)

Asteroseismic effects in close binary stars

Science.gov (United States)

Springer, Ofer M.; Shaviv, Nir J.

2013-09-01

Turbulent processes in the convective envelopes of the Sun and stars have been shown to be a source of internal acoustic excitations. In single stars, acoustic waves having frequencies below a certain cut-off frequency propagate nearly adiabatically and are effectively trapped below the photosphere where they are internally reflected. This reflection essentially occurs where the local wavelength becomes comparable to the pressure scale height. In close binary stars, the sound speed is a constant on equipotentials, while the pressure scale height, which depends on the local effective gravity, varies on equipotentials and may be much greater near the inner Lagrangian point (L1). As a result, waves reaching the vicinity of L1 may propagate unimpeded into low-density regions, where they tend to dissipate quickly due to non-linear and radiative effects. We study the three-dimensional propagation and enhanced damping of such waves inside a set of close binary stellar models using a WKB approximation of the acoustic field. We find that these waves can have much higher damping rates in close binaries, compared to their non-binary counterparts. We also find that the relative distribution of acoustic energy density at the visible surface of close binaries develops a ring-like feature at specific acoustic frequencies and binary separations.

Variable Stars Observed in the Galactic Disk by AST3-1 from Dome A, Antarctica

Energy Technology Data Exchange (ETDEWEB)

Wang, Lingzhi; Ma, Bin; Hu, Yi; Liu, Qiang; Shang, Zhaohui [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Li, Gang; Fu, Jianning [Department of Astronomy, Beijing Normal University, Beijing, 100875 (China); Wang, Lifan; Cui, Xiangqun; Du, Fujia; Gong, Xuefei; Li, Xiaoyan; Li, Zhengyang; Yuan, Xiangyan; Zhou, Jilin [Chinese Center for Antarctic Astronomy, Nanjing 210008 (China); Ashley, Michael C. B. [School of Physics, University of New South Wales, NSW 2052 (Australia); Pennypacker, Carl R. [Center for Astrophysics, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); York, Donald G., E-mail: wanglingzhi@bao.ac.cn [Department of Astronomy and Astrophysics and Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 (United States)

2017-03-01

AST3-1 is the second-generation wide-field optical photometric telescope dedicated to time-domain astronomy at Dome A, Antarctica. Here, we present the results of an i -band images survey from AST3-1 toward one Galactic disk field. Based on time-series photometry of 92,583 stars, 560 variable stars were detected with i magnitude ≤16.5 mag during eight days of observations; 339 of these are previously unknown variables. We tentatively classify the 560 variables as 285 eclipsing binaries (EW, EB, and EA), 27 pulsating variable stars ( δ Scuti, γ Doradus, δ Cephei variable, and RR Lyrae stars), and 248 other types of variables (unclassified periodic, multiperiodic, and aperiodic variable stars). Of the eclipsing binaries, 34 show O’Connell effects. One of the aperiodic variables shows a plateau light curve and another variable shows a secondary maximum after peak brightness. We also detected a complex binary system with an RS CVn-like light-curve morphology; this object is being followed-up spectroscopically using the Gemini South telescope.

Logistic chaotic maps for binary numbers generations

International Nuclear Information System (INIS)

Kanso, Ali; Smaoui, Nejib

2009-01-01

Two pseudorandom binary sequence generators, based on logistic chaotic maps intended for stream cipher applications, are proposed. The first is based on a single one-dimensional logistic map which exhibits random, noise-like properties at given certain parameter values, and the second is based on a combination of two logistic maps. The encryption step proposed in both algorithms consists of a simple bitwise XOR operation of the plaintext binary sequence with the keystream binary sequence to produce the ciphertext binary sequence. A threshold function is applied to convert the floating-point iterates into binary form. Experimental results show that the produced sequences possess high linear complexity and very good statistical properties. The systems are put forward for security evaluation by the cryptographic committees.

Converting optical scanning holograms of real objects to binary Fourier holograms using an iterative direct binary search algorithm.

Science.gov (United States)

Leportier, Thibault; Park, Min Chul; Kim, You Seok; Kim, Taegeun

2015-02-09

In this paper, we present a three-dimensional holographic imaging system. The proposed approach records a complex hologram of a real object using optical scanning holography, converts the complex form to binary data, and then reconstructs the recorded hologram using a spatial light modulator (SLM). The conversion from the recorded hologram to a binary hologram is achieved using a direct binary search algorithm. We present experimental results that verify the efficacy of our approach. To the best of our knowledge, this is the first time that a hologram of a real object has been reconstructed using a binary SLM.

EXTRASOLAR BINARY PLANETS. II. DETECTABILITY BY TRANSIT OBSERVATIONS

International Nuclear Information System (INIS)

Lewis, K. M.; Ida, S.; Ochiai, H.; Nagasawa, M.

2015-01-01

We discuss the detectability of gravitationally bound pairs of gas-giant planets (which we call “binary planets”) in extrasolar planetary systems that are formed through orbital instability followed by planet–planet dynamical tides during their close encounters, based on the results of N-body simulations by Ochiai et al. (Paper I). Paper I showed that the formation probability of a binary is as much as ∼10% for three giant planet systems that undergo orbital instability, and after post-capture long-term tidal evolution, the typical binary separation is three to five times the sum of the physical radii of the planets. The binary planets are stable during the main-sequence lifetime of solar-type stars, if the stellarcentric semimajor axis of the binary is larger than 0.3 AU. We show that detecting modulations of transit light curves is the most promising observational method to detect binary planets. Since the likely binary separations are comparable to the stellar diameter, the shape of the transit light curve is different from transit to transit, depending on the phase of the binary’s orbit. The transit durations and depth for binary planet transits are generally longer and deeper than those for the single planet case. We point out that binary planets could exist among the known inflated gas-giant planets or objects classified as false positive detections at orbital radii ≳0.3 AU, propose a binary planet explanation for the CoRoT candidate SRc01 E2 1066, and show that binary planets are likely to be present in, and could be detected using, Kepler-quality data

Interaction of Massive Black Hole Binaries with Their Stellar Environment. II. Loss Cone Depletion and Binary Orbital Decay

Science.gov (United States)

Sesana, Alberto; Haardt, Francesco; Madau, Piero

2007-05-01

We study the long-term evolution of massive black hole binaries (MBHBs) at the centers of galaxies using detailed scattering experiments to solve the full three-body problem. Ambient stars drawn from an isotropic Maxwellian distribution unbound to the binary are ejected by the gravitational slingshot. We construct a minimal, hybrid model for the depletion of the loss cone and the orbital decay of the binary and show that secondary slingshots-stars returning on small-impact parameter orbits to have a second superelastic scattering with the MBHB-may considerably help the shrinking of the pair in the case of large binary mass ratios. In the absence of loss cone refilling by two-body relaxation or other processes, the mass ejected before the stalling of a MBHB is half the binary reduced mass. About 50% of the ejected stars are expelled in a ``burst'' lasting ~104 yr M1/46, where M6 is the binary mass in units of 106 Msolar. The loss cone is completely emptied in a few bulge crossing timescales, ~107 yr M1/46. Even in the absence of two-body relaxation or gas dynamical processes, unequal mass and/or eccentric binaries with M6>~0.1 can shrink to the gravitational wave emission regime in less than a Hubble time and are therefore ``safe'' targets for the planned Laser Interferometer Space Antenna.

Determination of zeta-potential, charge, and number of organic ligands on the surface of water soluble quantum dots by capillary electrophoresis

Czech Academy of Sciences Publication Activity Database

Voráčová, Ivona; Klepárník, Karel; Lišková, Marcela; Foret, František

2015-01-01

Roč. 36, č. 6 (2015), s. 867-874 ISSN 0173-0835 R&D Projects: GA ČR(CZ) GA14-28254S Institutional support: RVO:68081715 Keywords : CE * LIF * zeta-potential * quantum dots Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.482, year: 2015

Zeta-function regularization approach to finite temperature effects in Kaluza-Klein space-times

International Nuclear Information System (INIS)

Bytsenko, A.A.; Vanzo, L.; Zerbini, S.

1992-01-01

In the framework of heat-kernel approach to zeta-function regularization, in this paper the one-loop effective potential at finite temperature for scalar and spinor fields on Kaluza-Klein space-time of the form M p x M c n , where M p is p-dimensional Minkowski space-time is evaluated. In particular, when the compact manifold is M c n = H n /Γ, the Selberg tracer formula associated with discrete torsion-free group Γ of the n-dimensional Lobachevsky space H n is used. An explicit representation for the thermodynamic potential valid for arbitrary temperature is found. As a result a complete high temperature expansion is presented and the roles of zero modes and topological contributions is discussed

Merger rate of primordial black-hole binaries

Science.gov (United States)

Ali-Haïmoud, Yacine; Kovetz, Ely D.; Kamionkowski, Marc

2017-12-01

Primordial black holes (PBHs) have long been a candidate for the elusive dark matter (DM), and remain poorly constrained in the ˜20 - 100 M⊙ mass range. PBH binaries were recently suggested as the possible source of LIGO's first detections. In this paper, we thoroughly revisit existing estimates of the merger rate of PBH binaries. We compute the probability distribution of orbital parameters for PBH binaries formed in the early Universe, accounting for tidal torquing by all other PBHs, as well as standard large-scale adiabatic perturbations. We then check whether the orbital parameters of PBH binaries formed in the early Universe can be significantly affected between formation and merger. Our analytic estimates indicate that the tidal field of halos and interactions with other PBHs, as well as dynamical friction by unbound standard DM particles, do not do significant work on nor torque PBH binaries. We estimate the torque due to baryon accretion to be much weaker than previous calculations, albeit possibly large enough to significantly affect the eccentricity of typical PBH binaries. We also revisit the PBH-binary merger rate resulting from gravitational capture in present-day halos, accounting for Poisson fluctuations. If binaries formed in the early Universe survive to the present time, as suggested by our analytic estimates, they dominate the total PBH merger rate. Moreover, this merger rate would be orders of magnitude larger than LIGO's current upper limits if PBHs make a significant fraction of the dark matter. As a consequence, LIGO would constrain ˜10 - 300 M⊙ PBHs to constitute no more than ˜1 % of the dark matter. To make this conclusion fully robust, though, numerical study of several complex astrophysical processes—such as the formation of the first PBH halos and how they may affect PBH binaries, as well as the accretion of gas onto an extremely eccentric binary—is needed.

MICROLENSING BINARIES DISCOVERED THROUGH HIGH-MAGNIFICATION CHANNEL

Energy Technology Data Exchange (ETDEWEB)

Shin, I.-G.; Choi, J.-Y.; Park, S.-Y.; Han, C. [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Gould, A.; Gaudi, B. S. [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Sumi, T. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Beaulieu, J.-P. [Institut d' Astrophysique de Paris, UMR7095 CNRS-Universite Pierre and Marie Curie, 98 bis Boulevard Arago, 75014 Paris (France); Dominik, M. [School of Physics and Astronomy, SUPA, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS (United Kingdom); Allen, W. [Vintage Lane Observatory, Blenheim (New Zealand); Bos, M. [Molehill Astronomical Observatory, North Shore (New Zealand); Christie, G. W. [Auckland Observatory, P.O. Box 24-180, Auckland (New Zealand); Depoy, D. L. [Department of Physics, Texas A and M University, College Station, TX (United States); Dong, S. [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Drummond, J. [Possum Observatory, Patutahi (New Zealand); Gal-Yam, A. [Benoziyo Center for Astrophysics, the Weizmann Institute (Israel); Hung, L.-W. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095 (United States); Janczak, J. [Department of Physics, Ohio State University, 191 W. Woodruff, Columbus, OH 43210 (United States); Kaspi, S. [School of Physics and Astronomy, Tel-Aviv University, Tel Aviv 69978 (Israel); Collaboration: muFUN Collaboration; MOA Collaboration; OGLE Collaboration; PLANET Collaboration; RoboNet Collaboration; MiNDSTEp Consortium; and others

2012-02-20

Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of eight binary-lensing events detected through the channel of high-magnification events during the seasons from 2007 to 2010. The perturbations, which are confined near the peak of the light curves, can be easily distinguished from the central perturbations caused by planets. However, the degeneracy between close and wide binary solutions cannot be resolved with a 3{sigma} confidence level for three events, implying that the degeneracy would be an important obstacle in studying binary distributions. The dependence of the degeneracy on the lensing parameters is consistent with a theoretical prediction that the degeneracy becomes severe as the binary separation and the mass ratio deviate from the values of resonant caustics. The measured mass ratio of the event OGLE-2008-BLG-510/MOA-2008-BLG-369 is q {approx} 0.1, making the companion of the lens a strong brown dwarf candidate.

Gaia Assorted Mass Binaries Long Excluded from SLoWPoKES (GAMBLES): Identifying Ultra-wide Binary Pairs with Components of Diverse Mass

Energy Technology Data Exchange (ETDEWEB)

Oelkers, Ryan J.; Stassun, Keivan G.; Dhital, Saurav, E-mail: ryan.j.oelkers@vanderbilt.edu [Vanderbilt University, Department of Physics and Astronomy, Nashville, TN 37235 (United States)

2017-06-01

The formation and evolution of binary star systems are some of the remaining key questions in modern astronomy. Wide binary pairs (separations >10{sup 3} au) are particularly intriguing because their low binding energies make it difficult for the stars to stay gravitationally bound over extended timescales, and thus to probe the dynamics of binary formation and dissolution. Our previous SLoWPoKES catalogs, I and II, provided the largest and most complete sample of wide-binary pairs of low masses. Here we present an extension of these catalogs to a broad range of stellar masses: the Gaia Assorted Mass Binaries Long Excluded from SloWPoKES (GAMBLES), comprising 8660 statistically significant wide pairs that we make available in a living online database. Within this catalog we identify a subset of 543 long-lived (dissipation timescale >1.5 Gyr) candidate binary pairs, of assorted mass, with typical separations between 10{sup 3} and 10{sup 5.5} au (0.002–1.5 pc), using the published distances and proper motions from the Tycho -Gaia Astrometric Solution and Sloan Digital Sky Survey photometry. Each pair has at most a false positive probability of 0.05; the total expectation is 2.44 false binaries in our sample. Among these, we find 22 systems with 3 components, 1 system with 4 components, and 15 pairs consisting of at least 1 possible red giant. We find the largest long-lived binary separation to be nearly 3.2 pc; even so, >76% of GAMBLES long-lived binaries have large binding energies and dissipation lifetimes longer than 1.5 Gyr. Finally, we find that the distribution of binary separations is clearly bimodal, corroborating the findings from SloWPoKES and suggesting multiple pathways for the formation and dissipation of the widest binaries in the Galaxy.

Gaia Assorted Mass Binaries Long Excluded from SLoWPoKES (GAMBLES): Identifying Ultra-wide Binary Pairs with Components of Diverse Mass

International Nuclear Information System (INIS)

Oelkers, Ryan J.; Stassun, Keivan G.; Dhital, Saurav

2017-01-01

The formation and evolution of binary star systems are some of the remaining key questions in modern astronomy. Wide binary pairs (separations >10 3 au) are particularly intriguing because their low binding energies make it difficult for the stars to stay gravitationally bound over extended timescales, and thus to probe the dynamics of binary formation and dissolution. Our previous SLoWPoKES catalogs, I and II, provided the largest and most complete sample of wide-binary pairs of low masses. Here we present an extension of these catalogs to a broad range of stellar masses: the Gaia Assorted Mass Binaries Long Excluded from SloWPoKES (GAMBLES), comprising 8660 statistically significant wide pairs that we make available in a living online database. Within this catalog we identify a subset of 543 long-lived (dissipation timescale >1.5 Gyr) candidate binary pairs, of assorted mass, with typical separations between 10 3 and 10 5.5 au (0.002–1.5 pc), using the published distances and proper motions from the Tycho -Gaia Astrometric Solution and Sloan Digital Sky Survey photometry. Each pair has at most a false positive probability of 0.05; the total expectation is 2.44 false binaries in our sample. Among these, we find 22 systems with 3 components, 1 system with 4 components, and 15 pairs consisting of at least 1 possible red giant. We find the largest long-lived binary separation to be nearly 3.2 pc; even so, >76% of GAMBLES long-lived binaries have large binding energies and dissipation lifetimes longer than 1.5 Gyr. Finally, we find that the distribution of binary separations is clearly bimodal, corroborating the findings from SloWPoKES and suggesting multiple pathways for the formation and dissipation of the widest binaries in the Galaxy.

Binary and ternary systems

International Nuclear Information System (INIS)

Petrov, D.A.

1986-01-01

Conditions for thermodynamical equilibrium in binary and ternary systems are considered. Main types of binary and ternary system phase diagrams are sequently constructed on the basis of general regularities on the character of transition from one equilibria to others. New statements on equilibrium line direction in the diagram triple points and their isothermal cross sections are developed. New represenations on equilibria in case of monovariant curve minimum and maximum on three-phase equilibrium formation in ternary system are introduced

Planet formation in Binaries

OpenAIRE

Thebault, Ph.; Haghighipour, N.

2014-01-01

Spurred by the discovery of numerous exoplanets in multiple systems, binaries have become in recent years one of the main topics in planet formation research. Numerous studies have investigated to what extent the presence of a stellar companion can affect the planet formation process. Such studies have implications that can reach beyond the sole context of binaries, as they allow to test certain aspects of the planet formation scenario by submitting them to extreme environments. We review her...

Non-negative Matrix Factorization for Binary Data

DEFF Research Database (Denmark)

Larsen, Jacob Søgaard; Clemmensen, Line Katrine Harder

We propose the Logistic Non-negative Matrix Factorization for decomposition of binary data. Binary data are frequently generated in e.g. text analysis, sensory data, market basket data etc. A common method for analysing non-negative data is the Non-negative Matrix Factorization, though...... this is in theory not appropriate for binary data, and thus we propose a novel Non-negative Matrix Factorization based on the logistic link function. Furthermore we generalize the method to handle missing data. The formulation of the method is compared to a previously proposed method (Tome et al., 2015). We compare...... the performance of the Logistic Non-negative Matrix Factorization to Least Squares Non-negative Matrix Factorization and Kullback-Leibler (KL) Non-negative Matrix Factorization on sets of binary data: a synthetic dataset, a set of student comments on their professors collected in a binary term-document matrix...

Binary and Millisecond Pulsars.

Science.gov (United States)

Lorimer, Duncan R

2008-01-01

We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1800. There are now 83 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 140 pulsars in 26 of the Galactic globular clusters. Recent highlights include the discovery of the young relativistic binary system PSR J1906+0746, a rejuvination in globular cluster pulsar research including growing numbers of pulsars with masses in excess of 1.5 M ⊙ , a precise measurement of relativistic spin precession in the double pulsar system and a Galactic millisecond pulsar in an eccentric ( e = 0.44) orbit around an unevolved companion. Supplementary material is available for this article at 10.12942/lrr-2008-8.

Flip-flopping binary black holes.

Science.gov (United States)

Lousto, Carlos O; Healy, James

2015-04-10

We study binary spinning black holes to display the long term individual spin dynamics. We perform a full numerical simulation starting at an initial proper separation of d≈25M between equal mass holes and evolve them down to merger for nearly 48 orbits, 3 precession cycles, and half of a flip-flop cycle. The simulation lasts for t=20 000M and displays a total change in the orientation of the spin of one of the black holes from an initial alignment with the orbital angular momentum to a complete antialignment after half of a flip-flop cycle. We compare this evolution with an integration of the 3.5 post-Newtonian equations of motion and spin evolution to show that this process continuously flip flops the spin during the lifetime of the binary until merger. We also provide lower order analytic expressions for the maximum flip-flop angle and frequency. We discuss the effects this dynamics may have on spin growth in accreting binaries and on the observational consequences for galactic and supermassive binary black holes.

Binary Star Fractions from the LAMOST DR4

Science.gov (United States)

Tian, Zhi-Jia; Liu, Xiao-Wei; Yuan, Hai-Bo; Chen, Bing-Qiu; Xiang, Mao-Sheng; Huang, Yang; Wang, Chun; Zhang, Hua-Wei; Guo, Jin-Cheng; Ren, Juan-Juan; Huo, Zhi-Ying; Yang, Yong; Zhang, Meng; Bi, Shao-Lan; Yang, Wu-Ming; Liu, Kang; Zhang, Xian-Fei; Li, Tan-Da; Wu, Ya-Qian; Zhang, Jing-Hua

2018-05-01

Stellar systems composed of single, double, triple or higher-order systems are rightfully regarded as the fundamental building blocks of the Milky Way. Binary stars play an important role in formation and evolution of the Galaxy. Through comparing the radial velocity variations from multi-epoch observations, we analyze the binary fraction of dwarf stars observed with LAMOST. Effects of different model assumptions, such as orbital period distributions on the estimate of binary fractions, are investigated. The results based on log-normal distribution of orbital periods reproduce the previous complete analyses better than the power-law distribution. We find that the binary fraction increases with T eff and decreases with [Fe/H]. We first investigate the relation between α-elements and binary fraction in such a large sample as provided by LAMOST. The old stars with high [α/Fe] dominate with a higher binary fraction than young stars with low [α/Fe]. At the same mass, earlier forming stars possess a higher binary fraction than newly forming ones, which may be related with evolution of the Galaxy.

WHITE-LIGHT FLARES ON CLOSE BINARIES OBSERVED WITH KEPLER

International Nuclear Information System (INIS)

Gao, Qing; Xin, Yu; Liu, Ji-Feng; Zhang, Xiao-Bin; Gao, Shuang

2016-01-01

Based on Kepler data, we present the results of a search for white light flares on 1049 close binaries. We identify 234 flare binaries, of which 6818 flares are detected. We compare the flare-binary fraction in different binary morphologies (“detachedness”). The result shows that the fractions in over-contact and ellipsoidal binaries are approximately 10%–20% lower than those in detached and semi-detached systems. We calculate the binary flare activity level (AL) of all the flare binaries, and discuss its variations along the orbital period ( P orb ) and rotation period ( P rot , calculated for only detached binaries). We find that the AL increases with decreasing P orb or P rot , up to the critical values at P orb ∼ 3 days or P rot ∼ 1.5 days, and thereafter the AL starts decreasing no matter how fast the stars rotate. We examine the flaring rate as a function of orbital phase in two eclipsing binaries on which a large number of flares are detected. It appears that there is no correlation between flaring rate and orbital phase in these two binaries. In contrast, when we examine the function with 203 flares on 20 non-eclipse ellipsoidal binaries, bimodal distribution of amplitude-weighted flare numbers shows up at orbital phases 0.25 and 0.75. Such variation could be larger than what is expected from the cross section modification.

Evolution and merging of binaries with compact objects

International Nuclear Information System (INIS)

Bethe, Hans A.; Brown, Gerald E.; Lee, Chang-Hwan

2007-01-01

In the light of recent observations in which short γ-ray bursts are interpreted as arising from black-hole(BH), neutron-star(NS) or NS-NS mergings we would like to review our research on the evolution of compact binaries, especially those containing NS's. These were carried out with predictions for LIGO in mind, but are directly applicable to short γ-ray bursts in the interpretation above. Most important in our review is that we show that the standard scenario for evolving NS-NS binaries always ends up with a low-mass BH (LMBH), NS binary. Bethe and Brown [1998, Astrophys. J. 506, 780] showed that this fate could be avoided if the two giants in the progenitor binary burned He at the same time, and that in this way the binary could avoid the common envelope evolution of the NS with red giant companion which sends the first born NS into a BH in the standard scenario. The burning of He at the same time requires, for the more massive giants such as the progenitors of the Hulse-Taylor binary NS that the two giants be within 4% of each other in zero age main sequence (ZAMS) mass. Applying this criterion to all binaries results in a factor ∼5 of LMBH-NS binaries as compared with NS-NS binaries. Although this factor is substantially less than the originally claimed factor of 20 which Bethe and Brown (1998) estimated, largely because a careful evolution has been carried through here, our factor 5 is augmented by a factor of ∼8 arising from the higher rate of star formation in the earlier Galaxy from which the BH-NS binaries came from. Furthermore, here we calculate the mergers for short-hard gamma-ray bursts, whereas Bethe and Brown's factor 20 included a factor of 2 for the higher chirp masses in a BH-NS binary as compared with NS-NS one. In short, we end up with an estimate of factor ∼40 over that calculated with NS-NS binary mergers in our Galaxy alone. Our total rate is estimated to be about one merging of compact objects per year. Our scenario of NS-NS binaries

Rotational properties of the binary and non-binary populations in the Trans-Neptunian belt

Science.gov (United States)

Thirouin, Audrey; Noll, Keith S.; Ortiz Moreno, Jose Luis; Morales , Nicolas

2014-11-01

An exhaustive study about short-term variability as well as derived properties from lightcurves allowed us to draw some conclusions for the Trans-Neptunian belt binary population. Based on Maxwellian fit distributions of the spin rate, we suggested that the binary population rotates slower than the non-binary one. This slowing-down can be attributed to tidal effects between the satellite and the primary, as expected. We showed that no system in this work is tidally locked, but the primary despinning process may have already affected the primary rate (as well as the satellite rotational rate). We used the Gladman et al. (1996) formula to compute the time required to tidally lock the systems, but this formula is based on several assumptions and approximations that do not always hold. The computed times are reasonable in most cases and confirm that none of the systems is tidally locked, assuming that the satellite densities are low and have a high rigidity or have a higher dissipation than usually assumed. The rotational properties of small bodies provide information about important physical properties, such as shape, density, and cohesion (Pravec & Harris 2000; Holsapple 2001, 2004; Thirouin et al. 2010, 2012). For binaries it is also possible to derive several physical parameters of the system components, such as diameters of the primary/secondary and albedo under some assumptions. We compare our results as well as our technique for deriving this information from the lightcurve with other methods, such as: i) thermal or thermophysical modeling, ii) from the mutual orbit of the binary component, iii) from direct imaging or iv) from stellar occultation by Trans-Neptunian Objects (TNOs). Finally, by studying the specific angular momentum of the sample, we proposed possible formation models for several binary TNOs. In several cases, we obtained hints of the formation mechanism from the angular momentum, but for other cases we do not have enough information about the

Texture classification by texton: statistical versus binary.

Directory of Open Access Journals (Sweden)

Zhenhua Guo

Full Text Available Using statistical textons for texture classification has shown great success recently. The maximal response 8 (Statistical_MR8, image patch (Statistical_Joint and locally invariant fractal (Statistical_Fractal are typical statistical texton algorithms and state-of-the-art texture classification methods. However, there are two limitations when using these methods. First, it needs a training stage to build a texton library, thus the recognition accuracy will be highly depended on the training samples; second, during feature extraction, local feature is assigned to a texton by searching for the nearest texton in the whole library, which is time consuming when the library size is big and the dimension of feature is high. To address the above two issues, in this paper, three binary texton counterpart methods were proposed, Binary_MR8, Binary_Joint, and Binary_Fractal. These methods do not require any training step but encode local feature into binary representation directly. The experimental results on the CUReT, UIUC and KTH-TIPS databases show that binary texton could get sound results with fast feature extraction, especially when the image size is not big and the quality of image is not poor.

Absolute Dimensions of Contact Binary Stars in Baade Window

Directory of Open Access Journals (Sweden)

Young Woon Kang

1999-12-01

Full Text Available The light curves of the representative 6 contact binary stars observed by OGLE Project of searching for dark matter in our Galaxy have been analyzed by the method of the Wilson and Devinney Differential Correction to find photometric solutions. The orbital inclinations of these binaries are in the range of 52 deg - 69 deg which is lower than that of the solar neighborhood binaries. The Roche lobe filling factor of these binaries are distributed in large range of 0.12 - 0.90. Since absence of spectroscopic observations for these binaries we have found masses of the 6 binary systems based on the intersection between Kepler locus and locus derived from Vandenberg isochrones in the mass - luminosity plane. Then absolute dimensions and distances have been found by combining the masses and the photometric solutions. The distances of the 6 binary systems are distributed in the range of 1 kpc - 6 kpc. This distance range is the limiting range where the contact binaries which have period shorter than a day are visible. Most contact binaries discovered in the Baade window do not belong to the Galactic bulge.

Orbital motion in pre-main sequence binaries

Energy Technology Data Exchange (ETDEWEB)

Schaefer, G. H. [The CHARA Array of Georgia State University, Mount Wilson Observatory, Mount Wilson, CA 91023 (United States); Prato, L. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Simon, M. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Patience, J., E-mail: schaefer@chara-array.org [Astrophysics Group, School of Physics, University of Exeter, Exeter, EX4 4QL (United Kingdom)

2014-06-01

We present results from our ongoing program to map the visual orbits of pre-main sequence (PMS) binaries in the Taurus star forming region using adaptive optics imaging at the Keck Observatory. We combine our results with measurements reported in the literature to analyze the orbital motion for each binary. We present preliminary orbits for DF Tau, T Tau S, ZZ Tau, and the Pleiades binary HBC 351. Seven additional binaries show curvature in their relative motion. Currently, we can place lower limits on the orbital periods for these systems; full solutions will be possible with more orbital coverage. Five other binaries show motion that is indistinguishable from linear motion. We suspect that these systems are bound and might show curvature with additional measurements in the future. The observations reported herein lay critical groundwork toward the goal of measuring precise masses for low-mass PMS stars.

Binary catalogue of exoplanets

Science.gov (United States)

Schwarz, Richard; Bazso, Akos; Zechner, Renate; Funk, Barbara

2016-02-01

Since 1995 there is a database which list most of the known exoplanets (The Extrasolar Planets Encyclopaedia at http://exoplanet.eu/). With the growing number of detected exoplanets in binary and multiple star systems it became more important to mark and to separate them into a new database, which is not available in the Extrasolar Planets Encyclopaedia. Therefore we established an online database (which can be found at: http://www.univie.ac.at/adg/schwarz/multiple.html) for all known exoplanets in binary star systems and in addition for multiple star systems, which will be updated regularly and linked to the Extrasolar Planets Encyclopaedia. The binary catalogue of exoplanets is available online as data file and can be used for statistical purposes. Our database is divided into two parts: the data of the stars and the planets, given in a separate list. We describe also the different parameters of the exoplanetary systems and present some applications.

Serial binary interval ratios improve rhythm reproduction

Directory of Open Access Journals (Sweden)

Xiang eWu

2013-08-01

Full Text Available Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8, non-binary integer (1:3:5:6, and non-integer (1:2.3:5.3:6.4 ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

Serial binary interval ratios improve rhythm reproduction.

Science.gov (United States)

Wu, Xiang; Westanmo, Anders; Zhou, Liang; Pan, Junhao

2013-01-01

Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8), non-binary integer (1:3:5:6), and non-integer (1:2.3:5.3:6.4) ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

BHDD: Primordial black hole binaries code

Science.gov (United States)

Kavanagh, Bradley J.; Gaggero, Daniele; Bertone, Gianfranco

2018-06-01

BHDD (BlackHolesDarkDress) simulates primordial black hole (PBH) binaries that are clothed in dark matter (DM) halos. The software uses N-body simulations and analytical estimates to follow the evolution of PBH binaries formed in the early Universe.

Tidal and magnetic interactions in close binary stars

International Nuclear Information System (INIS)

Campbell, C.G.

1983-03-01

The thesis investigates the nature of non-synchronous motions in members of close binary stars under the influence of gravitational and magnetic fields existing in these systems, and the evolution of such motions in different classes of binaries. Largely convective stars are considered and a solution is found for the fluid flow associated with the non-synchronous rotation of such a secondary in a close binary system, taking tidal and rotational forces into account. The tidal velocity field is calculated for a low mass white dwarf secondary star in a twin - degenerate binary. It is found that the synchronisation times can be comparable to the lifetime of the binary so that some asynchronism may remain present. (U.K.)

Chemical Composition of the RS CNn-Type Star 33 Piscium

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Barisevišius G.

2011-03-01

Full Text Available Abundances of 22 chemical elements, including the key elements and isotopes such as 12C, 13C, N and O, are investigated in the spectrum of 33 Psc, a single-lined RS CVn-type binary of low magnetic activity. The high resolution spectra were observed on the Nordic Optical Telescope and analyzed with the MARCS model atmospheres. The following main parameters have been determined: Teff = 4750 K, log g = 2.8, [Fe/H] = -0.09, [C/Fe] = -0.04, [N/Fe] = 0.23, [O/Fe] = 0.05, C/N = 2.14, 12C/13C = 30, which show the first-dredge-up mixing signatures and no extra-mixing.

Dynamical Formation and Merger of Binary Black Holes

Science.gov (United States)

Stone, Nicholas

2017-01-01

The advent of gravitational wave (GW) astronomy began with Advanced LIGO's 2015 discovery of GWs from coalescing black hole (BH) binaries. GW astronomy holds great promise for testing general relativity, but also for investigating open astrophysical questions not amenable to traditional electromagnetic observations. One such question concerns the origin of stellar mass BH binaries in the universe: do these form primarily from evolution of isolated binaries of massive stars, or do they form through more exotic dynamical channels? The best studied dynamical formation channel involves multibody interactions of BHs and stars in dense globular cluster environments, but many other dynamical scenarios have recently been proposed, ranging from the Kozai effect in hierarchical triple systems to BH binary formation in the outskirts of Toomre-unstable accretion disks surrounding supermassive black holes. The BH binaries formed through these processes will have different distributions of observable parameters (e.g. mass ratios, spins) than BH binaries formed through the evolution of isolated binary stars. In my talk I will overview these and other dynamical formation scenarios, and summarize the key observational tests that will enable Advanced LIGO or other future detectors to determine what formation pathway creates the majority of binary BHs in the universe. NCS thanks NASA, which has funded his work through Einstein postdoctoral grant PF5-160145.

Cellular internalization of polycation-coated microparticles and its dependence on their zeta potential

Science.gov (United States)

Kato, Noritaka; Kondo, Ryosuke

2018-03-01

By applying microparticles to HeLa cells, the number of particles adhered on the cell and that of the ones internalized in the cells were evaluated. Three-dimensional tomographic images of the cells with the particles were obtained by multiphoton excitation laser scanning microscopy, and the adhered and internalized particles were counted separately. When the surface charge of the particles was reversed from negative to positive by coating the particles with polycations, both numbers significantly increased owing to the electrostatic attraction between the cells and the polycation-coated particles. Four different positively charged particles were prepared using four different polycations, and the numbers of adhered and internalized particles were compared. Our results suggest that these numbers depended on the zeta potential rather than the molecular structure of the polycation.

Black Hole/Pulsar Binaries in the Galaxy

Science.gov (United States)

Shao, Yong; Li, Xiang-Dong

2018-04-01

We have performed population synthesis calculation on the formation of binaries containing a black hole (BH) and a neutron star (NS) in the Galactic disk. Some of important input parameters, especially for the treatment of common envelope evolution, are updated in the calculation. We have discussed the uncertainties from the star formation rate of the Galaxy and the velocity distribution of NS kicks on the birthrate (˜ 0.6-13 Myr^{-1}) of BH/NS binaries. From incident BH/NS binaries, by modelling the orbital evolution duo to gravitational wave radiation and the NS evolution as radio pulsars, we obtain the distributions of the observable parameters such as the orbital period, eccentricity and pulse period of the BH/pulsar binaries. We estimate that there may be ˜3 - 80 BH/pulsar binaries in the Galactic disk and around 10% of them could be detected by the Five-hundred-meter Aperture Spherical radio Telescope.

Investigating Dark Energy with Black Hole Binaries

International Nuclear Information System (INIS)

Mersini-Houghton, Laura; Kelleher, Adam

2009-01-01

The accelerated expansion of the universe is ascribed to the existence of dark energy. Black holes accrete dark energy. The accretion induces a mass change proportional to the energy density and pressure of the background dark energy fluid. The time scale during which the mass of black holes changes considerably is long relative to the age of the universe, thus beyond detection possibilities. We propose to take advantage of the modified black hole masses for exploring the equation of state w[z] of dark energy, by investigating the evolution of supermassive black hole binaries on a dark energy background. Deriving the signatures of dark energy accretion on the evolution of binaries, we find that dark energy imprints on the emitted gravitational radiation and on the changes in the orbital radius of the binary can be within detection limits for certain supermassive black hole binaries. This talk describes how binaries can provide a useful tool in obtaining complementary information on the nature of dark energy.

Black hole/pulsar binaries in the Galaxy

Science.gov (United States)

Shao, Yong; Li, Xiang-Dong

2018-06-01

We have performed population synthesis calculation on the formation of binaries containing a black hole (BH) and a neutron star (NS) in the Galactic disc. Some of important input parameters, especially for the treatment of common envelope evolution, are updated in the calculation. We have discussed the uncertainties from the star formation rate of the Galaxy and the velocity distribution of NS kicks on the birthrate (˜ 0.6-13 M yr^{-1}) of BH/NS binaries. From incident BH/NS binaries, by modelling the orbital evolution due to gravitational wave radiation and the NS evolution as radio pulsars, we obtain the distributions of the observable parameters such as the orbital period, eccentricity, and pulse period of the BH/pulsar binaries. We estimate that there may be ˜3-80 BH/pulsar binaries in the Galactic disc and around 10 per cent of them could be detected by the Five-hundred-metre Aperture Spherical radio Telescope.

Star formation history: Modeling of visual binaries

Science.gov (United States)

Gebrehiwot, Y. M.; Tessema, S. B.; Malkov, O. Yu.; Kovaleva, D. A.; Sytov, A. Yu.; Tutukov, A. V.

2018-05-01

Most stars form in binary or multiple systems. Their evolution is defined by masses of components, orbital separation and eccentricity. In order to understand star formation and evolutionary processes, it is vital to find distributions of physical parameters of binaries. We have carried out Monte Carlo simulations in which we simulate different pairing scenarios: random pairing, primary-constrained pairing, split-core pairing, and total and primary pairing in order to get distributions of binaries over physical parameters at birth. Next, for comparison with observations, we account for stellar evolution and selection effects. Brightness, radius, temperature, and other parameters of components are assigned or calculated according to approximate relations for stars in different evolutionary stages (main-sequence stars, red giants, white dwarfs, relativistic objects). Evolutionary stage is defined as a function of system age and component masses. We compare our results with the observed IMF, binarity rate, and binary mass-ratio distributions for field visual binaries to find initial distributions and pairing scenarios that produce observed distributions.

Multireference configuration interaction treatment of potential energy surfaces: symmetric dissociation of H/sub 2/O in a double-zeta basis

Energy Technology Data Exchange (ETDEWEB)

Brown, F B; Shavitt, I; Shepard, R

1984-03-23

Multiconfiguration self-consistent fields (SCF) and multireference configurational interaction (CI) calculations have been performed for the H/sub 2/O molecule in a double-zeta basis for four symmetric geometries, for comparison with full CI results. Unlike single-reference results, the energy errors are almost independent of geometry, allowing unbiased treatments of potential energy surfaces. 35 references, 1 figure, 2 tables.

Eliciting Subjective Probabilities with Binary Lotteries

DEFF Research Database (Denmark)

Harrison, Glenn W.; Martínez-Correa, Jimmy; Swarthout, J. Todd

objective probabilities. Drawing a sample from the same subject population, we find evidence that the binary lottery procedure induces linear utility in a subjective probability elicitation task using the Quadratic Scoring Rule. We also show that the binary lottery procedure can induce direct revelation...

RATES AND DELAY TIMES OF TYPE Ia SUPERNOVAE

International Nuclear Information System (INIS)

Ruiter, Ashley J.; Belczynski, Krzysztof; Fryer, Chris

2009-01-01

We analyze the evolution of binary stars to calculate synthetic rates and delay times of the most promising Type Ia Supernovae (SNe Ia) progenitors. We present and discuss evolutionary scenarios in which a white dwarf (WD) reaches the Chandrasekhar mass and potentially explodes in a SNe Ia. We consider Double Degenerate (DDS; merger of two WDs), Single Degenerate (SDS; WD accreting from H-rich companion), and AM Canum Venaticorum (AM CVn; WD accreting from He-rich companion) scenarios. The results are presented for two different star formation histories: burst (elliptical-like galaxies) and continuous (spiral-like galaxies). It is found that delay times for the DDS in our standard model (with common envelope efficiency α CE = 1) follow a power-law distribution. For the SDS we note a wide range of delay times, while AM CVn progenitors produce a short burst of SNe Ia at early times. The DDS median delay time falls between ∼0.5 and 1 Gyr; the SDS between ∼2 and 3 Gyr; and the AM CVn between ∼0.8 and 0.6 Gyr depending on the assumed α CE . For a Milky-Way-like (MW-like) galaxy, we estimate the rates of SNe Ia arising from different progenitors as: ∼10 -4 yr -1 for the SDS and AM CVn, and ∼10 -3 yr -1 for the DDS. We point out that only the rates for two merging carbon-oxygen WDs, the only systems found in the DDS, are consistent with the observed rates for typical MW-like spirals. We also note that DDS progenitors are the dominant population in elliptical galaxies. The fact that the delay time distribution for the DDS follows a power law implies more SNe Ia (per unit mass) in young rather than in aged populations. Our results do not exclude other scenarios, but strongly indicate that the DDS is the dominant channel generating SNe Ia in spiral galaxies, at least in the framework of our adopted evolutionary models. Since it is believed that WD mergers cannot produce a thermonuclear explosion given the current understanding of accreting WDs, either the

DNA polymerase zeta cooperates with polymerases kappa and iota in translesion DNA synthesis across pyrimidine photodimers in cells from XPV patients.

Science.gov (United States)

Ziv, Omer; Geacintov, Nicholas; Nakajima, Satoshi; Yasui, Akira; Livneh, Zvi

2009-07-14

Human cells tolerate UV-induced cyclobutane pyrimidine dimers (CPD) by translesion DNA synthesis (TLS), carried out by DNA polymerase eta, the POLH gene product. A deficiency in DNA polymerase eta due to germ-line mutations in POLH causes the hereditary disease xeroderma pigmentosum variant (XPV), which is characterized by sunlight sensitivity and extreme predisposition to sunlight-induced skin cancer. XPV cells are UV hypermutable due to the activity of mutagenic TLS across CPD, which explains the cancer predisposition of the patients. However, the identity of the backup polymerase that carries out this mutagenic TLS was unclear. Here, we show that DNA polymerase zeta cooperates with DNA polymerases kappa and iota to carry out error-prone TLS across a TT CPD. Moreover, DNA polymerases zeta and kappa, but not iota, protect XPV cells against UV cytotoxicity, independently of nucleotide excision repair. This presents an extreme example of benefit-risk balance in the activity of TLS polymerases, which provide protection against UV cytotoxicity at the cost of increased mutagenic load.

Variance in binary stellar population synthesis

Science.gov (United States)

Breivik, Katelyn; Larson, Shane L.

2016-03-01

In the years preceding LISA, Milky Way compact binary population simulations can be used to inform the science capabilities of the mission. Galactic population simulation efforts generally focus on high fidelity models that require extensive computational power to produce a single simulated population for each model. Each simulated population represents an incomplete sample of the functions governing compact binary evolution, thus introducing variance from one simulation to another. We present a rapid Monte Carlo population simulation technique that can simulate thousands of populations in less than a week, thus allowing a full exploration of the variance associated with a binary stellar evolution model.

"Binary" and "non-binary" detection tasks: are current performance measures optimal?

Science.gov (United States)

Gur, David; Rockette, Howard E; Bandos, Andriy I

2007-07-01

We have observed that a very large fraction of responses for several detection tasks during the performance of observer studies are in the extreme ranges of lower than 11% or higher than 89% regardless of the actual presence or absence of the abnormality in question or its subjectively rated "subtleness." This observation raises questions regarding the validity and appropriateness of using multicategory rating scales for such detection tasks. Monte Carlo simulation of binary and multicategory ratings for these tasks demonstrate that the use of the former (binary) often results in a less biased and more precise summary index and hence may lead to a higher statistical power for determining differences between modalities.

Unravelling the Nature of HD 81032 – A New RS CVn Binary J. C. ...

Indian Academy of Sciences (India)

A signal-to-noise of ratio between 20 and 40 was achieved in these spectra. ... to 12th. The exposure time was 501s, and was accumulated in 26 separate short scans ..... fluxes. However, only upper limits are available at 25, 60 and 100 µm.

Multiple zeta functions and double wrapping in planar N=4 SYM

Science.gov (United States)

Leurent, Sébastien; Volin, Dmytro

2013-10-01

Using the FiNLIE solution of the AdS/CFT Y-system, we compute the anomalous dimension of the Konishi operator in planar N=4 SYM up to eight loops, i.e. up to the leading double wrapping order. At this order a non-reducible Euler-Zagier sum, ζ1,2,8, appears for the first time. We find that at all orders in perturbation, every spectral-dependent quantity of the Y-system is expressed through multiple Hurwitz zeta functions, hence we provide a Mathematica package to manipulate these functions, including the particular case of Euler-Zagier sums. Furthermore, we conjecture that only Euler-Zagier sums can appear in the answer for the anomalous dimension at any order in perturbation theory. We also resum the leading transcendentality terms of the anomalous dimension at all orders, obtaining a simple result in terms of Bessel functions. Finally, we demonstrate that exact Bethe equations should be related to an absence of poles condition that becomes especially non-trivial at double wrapping.

MARVELS Radial Velocity Solutions to Seven Kepler Eclipsing Binaries

Science.gov (United States)

Heslar, Michael Francis; Thomas, Neil B.; Ge, Jian; Ma, Bo; Herczeg, Alec; Reyes, Alan; SDSS-III MARVELS Team

2016-01-01

Eclipsing binaries serve momentous purposes to improve the basis of understanding aspects of stellar astrophysics, such as the accurate calculation of the physical parameters of stars and the enigmatic mass-radius relationship of M and K dwarfs. We report the investigation results of 7 eclipsing binary candidates, initially identified by the Kepler mission, overlapped with the radial velocity observations from the SDSS-III Multi-Object APO Radial-Velocity Exoplanet Large-Area Survey (MARVELS). The RV extractions and spectroscopic solutions of these eclipsing binaries were generated by the University of Florida's 1D data pipeline with a median RV precision of ~60-100 m/s, which was utilized for the DR12 data release. We performed the cross-reference fitting of the MARVELS RV data and the Kepler photometric fluxes obtained from the Kepler Eclipsing Binary Catalog (V2) and modelled the 7 eclipsing binaries in the BinaryMaker3 and PHOEBE programs. This analysis accurately determined the absolute physical and orbital parameters of each binary. Most of the companion stars were determined to have masses of K and M dwarf stars (0.3-0.8 M⊙), and allowed for an investigation into the mass-radius relationship of M and K dwarfs. Among the cases are KIC 9163796, a 122.2 day period "heartbeat star", a recently-discovered class of eccentric binaries known for tidal distortions and pulsations, with a high eccentricity (e~0.75) and KIC 11244501, a 0.29 day period, contact binary with a double-lined spectrum and mass ratio (q~0.45). We also report on the possible reclassification of 2 Kepler eclipsing binary candidates as background eclipsing binaries based on the analysis of the flux measurements, flux ratios of the spectroscopic and photometric solutions, the differences in the FOVs, the image processing of Kepler, and RV and spectral analysis of MARVELS.

ZETA POTENTIAL AND COLOR INVESTIGATIONS OF VEGETABLE OIL BASED EMULSIONS AS ECO-FRIENDLY LUBRICANTS

Directory of Open Access Journals (Sweden)

ROMICĂ CREŢU

2017-06-01

Full Text Available In the past 10 years, the need for biodegradable lubricants has been more and more emphasized. The use of vegetable oils as lubricants offers several advantages. The vegetable oils are biodegradable; thus, the environmental pollution is minimal either during or after their use. The aim of this paper is to presents a preliminary study concerning the influence of some preparation conditions on the stability of vegetable oil-in-water (O/W emulsions as eco-friendly lubricants stabilized by nonionic surfactant. In this context, vegetable oil-in-water emulsions characteristics where assessed using microscopically observation and zeta potential. In addition, the color of these emulsions can be evaluated. It can be observed that the emulsions tend to stabilize in time.

Joule heating effects on electromagnetohydrodynamic flow through a peristaltically induced micro-channel with different zeta potential and wall slip

Science.gov (United States)

Ranjit, N. K.; Shit, G. C.

2017-09-01

This paper aims to develop a mathematical model for magnetohydrodynamic flow of biofluids through a hydrophobic micro-channel with periodically contracting and expanding walls under the influence of an axially applied electric field. The velocity slip effects have been taken into account at the channel walls by employing different slip lengths due to hydrophobic gating. Different temperature jump factors have also been used to investigate the thermomechanical interactions at the fluid-solid interface. The electromagnetohydrodynamic flow in a microchannel is simplified under the framework of Debye-Hückel linearization approximation. We have derived the closed-form solutions for the linearized dimensionless boundary value problem under the assumptions of long wave length and low Reynolds number. The axial velocity, temperature, pressure distribution, stream function, wall shear stress and the Nusselt number have been appraised for diverse values of the parameters approaching into the problem. Our main focus is to determine the effects of different zeta potential on the axial velocity and temperature distribution under electromagnetic environment. This study puts forward an important observation that the different zeta potential plays an important role in controlling fluid velocity. The study further reveals that the temperature increases significantly with the Joule heating parameter and the Brinkman number (arises due to the dissipation of energy).

The Isolation of DNA by Polycharged Magnetic Particles: An Analysis of the Interaction by Zeta Potential and Particle Size.

Science.gov (United States)

Haddad, Yazan; Xhaxhiu, Kledi; Kopel, Pavel; Hynek, David; Zitka, Ondrej; Adam, Vojtech

2016-04-20

Magnetic isolation of biological targets is in major demand in the biotechnology industry today. This study considers the interaction of four surface-modified magnetic micro- and nanoparticles with selected DNA fragments. Different surface modifications of nanomaghemite precursors were investigated: MAN37 (silica-coated), MAN127 (polyvinylpyrrolidone-coated), MAN158 (phosphate-coated), and MAN164 (tripolyphosphate-coated). All particles were positive polycharged agglomerated monodispersed systems. Mean particle sizes were 0.48, 2.97, 2.93, and 3.67 μm for MAN37, MAN127, MAN164, and MAN158, respectively. DNA fragments exhibited negative zeta potential of -0.22 mV under binding conditions (high ionic strength, low pH, and dehydration). A decrease in zeta potential of particles upon exposure to DNA was observed with exception of MAN158 particles. The measured particle size of MAN164 particles increased by nearly twofold upon exposure to DNA. Quantitative PCR isolation of DNA with a high retrieval rate was observed by magnetic particles MAN127 and MAN164. Interaction between polycharged magnetic particles and DNA is mediated by various binding mechanisms such as hydrophobic and electrostatic interactions. Future development of DNA isolation technology requires an understanding of the physical and biochemical conditions of this process.

Compact stars and the evolution of binary systems

NARCIS (Netherlands)

van den Heuvel, E.P.J.

2011-01-01

The Chandrasekhar limit is of key importance for the evolution of white dwarfs in binary systems and for the formation of neutron stars and black holes in binaries. Mass transfer can drive a white dwarf in a binary over the Chandrasekhar limit, which may lead to a Type Ia supernova (in case of a CO

WHITE-DWARF-MAIN-SEQUENCE BINARIES IDENTIFIED FROM THE LAMOST PILOT SURVEY

International Nuclear Information System (INIS)

Ren Juanjuan; Luo Ali; Li Yinbi; Wei Peng; Zhao Jingkun; Zhao Yongheng; Song Yihan; Zhao Gang

2013-01-01

We present a set of white-dwarf-main-sequence (WDMS) binaries identified spectroscopically from the Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST, also called the Guo Shou Jing Telescope) pilot survey. We develop a color selection criteria based on what is so far the largest and most complete Sloan Digital Sky Survey (SDSS) DR7 WDMS binary catalog and identify 28 WDMS binaries within the LAMOST pilot survey. The primaries in our binary sample are mostly DA white dwarfs except for one DB white dwarf. We derive the stellar atmospheric parameters, masses, and radii for the two components of 10 of our binaries. We also provide cooling ages for the white dwarf primaries as well as the spectral types for the companion stars of these 10 WDMS binaries. These binaries tend to contain hot white dwarfs and early-type companions. Through cross-identification, we note that nine binaries in our sample have been published in the SDSS DR7 WDMS binary catalog. Nineteen spectroscopic WDMS binaries identified by the LAMOST pilot survey are new. Using the 3σ radial velocity variation as a criterion, we find two post-common-envelope binary candidates from our WDMS binary sample

BROWN DWARF BINARIES FROM DISINTEGRATING TRIPLE SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Reipurth, Bo [Institute for Astronomy and NASA Astrobiology Institute University of Hawaii, 640 N. Aohoku Place, Hilo, HI 96720 (United States); Mikkola, Seppo, E-mail: reipurth@ifa.hawaii.edu, E-mail: Seppo.Mikkola@utu.fi [Tuorla Observatory, University of Turku, Väisäläntie 20, Piikkiö (Finland)

2015-04-15

Binaries in which both components are brown dwarfs (BDs) are being discovered at an increasing rate, and their properties may hold clues to their origin. We have carried out 200,000 N-body simulations of three identical stellar embryos with masses drawn from a Chabrier IMF and embedded in a molecular core. The bodies are initially non-hierarchical and undergo chaotic motions within the cloud core, while accreting using Bondi–Hoyle accretion. The coupling of dynamics and accretion often leads to one or two dominant bodies controlling the center of the cloud core, while banishing the other(s) to the lower-density outskirts, leading to stunted growth. Eventually each system transforms either to a bound hierarchical configuration or breaks apart into separate single and binary components. The orbital motion is followed for 100 Myr. In order to illustrate 200,000 end-states of such dynamical evolution with accretion, we introduce the “triple diagnostic diagram,” which plots two dimensionless numbers against each other, representing the binary mass ratio and the mass ratio of the third body to the total system mass. Numerous freefloating BD binaries are formed in these simulations, and statistical properties are derived. The separation distribution function is in good correspondence with observations, showing a steep rise at close separations, peaking around 13 AU and declining more gently, reaching zero at separations greater than 200 AU. Unresolved BD triple systems may appear as wider BD binaries. Mass ratios are strongly peaked toward unity, as observed, but this is partially due to the initial assumptions. Eccentricities gradually increase toward higher values, due to the lack of viscous interactions in the simulations, which would both shrink the orbits and decrease their eccentricities. Most newborn triple systems are unstable and while there are 9209 ejected BD binaries at 1 Myr, corresponding to about 4% of the 200,000 simulations, this number has grown to

BROWN DWARF BINARIES FROM DISINTEGRATING TRIPLE SYSTEMS

International Nuclear Information System (INIS)

Reipurth, Bo; Mikkola, Seppo

2015-01-01

Binaries in which both components are brown dwarfs (BDs) are being discovered at an increasing rate, and their properties may hold clues to their origin. We have carried out 200,000 N-body simulations of three identical stellar embryos with masses drawn from a Chabrier IMF and embedded in a molecular core. The bodies are initially non-hierarchical and undergo chaotic motions within the cloud core, while accreting using Bondi–Hoyle accretion. The coupling of dynamics and accretion often leads to one or two dominant bodies controlling the center of the cloud core, while banishing the other(s) to the lower-density outskirts, leading to stunted growth. Eventually each system transforms either to a bound hierarchical configuration or breaks apart into separate single and binary components. The orbital motion is followed for 100 Myr. In order to illustrate 200,000 end-states of such dynamical evolution with accretion, we introduce the “triple diagnostic diagram,” which plots two dimensionless numbers against each other, representing the binary mass ratio and the mass ratio of the third body to the total system mass. Numerous freefloating BD binaries are formed in these simulations, and statistical properties are derived. The separation distribution function is in good correspondence with observations, showing a steep rise at close separations, peaking around 13 AU and declining more gently, reaching zero at separations greater than 200 AU. Unresolved BD triple systems may appear as wider BD binaries. Mass ratios are strongly peaked toward unity, as observed, but this is partially due to the initial assumptions. Eccentricities gradually increase toward higher values, due to the lack of viscous interactions in the simulations, which would both shrink the orbits and decrease their eccentricities. Most newborn triple systems are unstable and while there are 9209 ejected BD binaries at 1 Myr, corresponding to about 4% of the 200,000 simulations, this number has grown to

Dynamical zeta functions and dynamical determinants for hyperbolic maps a functional approach

CERN Document Server

Baladi, Viviane

2018-01-01

The spectra of transfer operators associated to dynamical systems, when acting on suitable Banach spaces, contain key information about the ergodic properties of the systems. Focusing on expanding and hyperbolic maps, this book gives a self-contained account on the relation between zeroes of dynamical determinants, poles of dynamical zeta functions, and the discrete spectra of the transfer operators. In the hyperbolic case, the first key step consists in constructing a suitable Banach space of anisotropic distributions. The first part of the book is devoted to the easier case of expanding endomorphisms, showing how the (isotropic) function spaces relevant there can be studied via Paley–Littlewood decompositions, and allowing easier access to the construction of the anisotropic spaces which is performed in the second part. This is the first book describing the use of anisotropic spaces in dynamics. Aimed at researchers and graduate students, it presents results and techniques developed since the beginning of...

Non-binary or genderqueer genders.

Science.gov (United States)

Richards, Christina; Bouman, Walter Pierre; Seal, Leighton; Barker, Meg John; Nieder, Timo O; T'Sjoen, Guy

2016-01-01

Some people have a gender which is neither male nor female and may identify as both male and female at one time, as different genders at different times, as no gender at all, or dispute the very idea of only two genders. The umbrella terms for such genders are 'genderqueer' or 'non-binary' genders. Such gender identities outside of the binary of female and male are increasingly being recognized in legal, medical and psychological systems and diagnostic classifications in line with the emerging presence and advocacy of these groups of people. Population-based studies show a small percentage--but a sizable proportion in terms of raw numbers--of people who identify as non-binary. While such genders have been extant historically and globally, they remain marginalized, and as such--while not being disorders or pathological in themselves--people with such genders remain at risk of victimization and of minority or marginalization stress as a result of discrimination. This paper therefore reviews the limited literature on this field and considers ways in which (mental) health professionals may assist the people with genderqueer and non-binary gender identities and/or expressions they may see in their practice. Treatment options and associated risks are discussed.

The Young Visual Binary Survey

Science.gov (United States)

Prato, Lisa; Avilez, Ian; Lindstrom, Kyle; Graham, Sean; Sullivan, Kendall; Biddle, Lauren; Skiff, Brian; Nofi, Larissa; Schaefer, Gail; Simon, Michal

2018-01-01

Differences in the stellar and circumstellar properties of the components of young binaries provide key information about star and disk formation and evolution processes. Because objects with separations of a few to a few hundred astronomical units share a common environment and composition, multiple systems allow us to control for some of the factors which play into star formation. We are completing analysis of a rich sample of about 100 pre-main sequence binaries and higher order multiples, primarily located in the Taurus and Ophiuchus star forming regions. This poster will highlight some of out recent, exciting results. All reduced spectra and the results of our analysis will be publicly available to the community at http://jumar.lowell.edu/BinaryStars/. Support for this research was provided in part by NSF award AST-1313399 and by NASA Keck KPDA funding.

A Survey of Binary Similarity and Distance Measures

Directory of Open Access Journals (Sweden)

Seung-Seok Choi

2010-02-01

Full Text Available The binary feature vector is one of the most common representations of patterns and measuring similarity and distance measures play a critical role in many problems such as clustering, classification, etc. Ever since Jaccard proposed a similarity measure to classify ecological species in 1901, numerous binary similarity and distance measures have been proposed in various fields. Applying appropriate measures results in more accurate data analysis. Notwithstanding, few comprehensive surveys on binary measures have been conducted. Hence we collected 76 binary similarity and distance measures used over the last century and reveal their correlations through the hierarchical clustering technique.

The binary white dwarf LHS 3236

Energy Technology Data Exchange (ETDEWEB)

Harris, Hugh C.; Dahn, Conard C.; Canzian, Blaise; Guetter, Harry H.; Levine, Stephen E.; Luginbuhl, Christian B.; Monet, Alice K. B.; Stone, Ronald C.; Subasavage, John P.; Tilleman, Trudy; Walker, Richard L. [US Naval Observatory, 10391 West Naval Observatory Road, Flagstaff, AZ 86001-8521 (United States); Dupuy, Trent J.; Liu, Michael C. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Hartkopf, William I. [US Naval Observatory, 3450 Massachusetts Avenue, N.W., Washington, DC 20392-5420 (United States); Ireland, Michael J. [Department of Physics and Astronomy, Macquarie University, New South Wales, NSW 2109 (Australia); Leggett, S. K., E-mail: hch@nofs.navy.mil [Gemini Observatory, 670 N. Aohoku Place, Hilo, HI 96720 (United States)

2013-12-10

The white dwarf LHS 3236 (WD1639+153) is shown to be a double-degenerate binary, with each component having a high mass. Astrometry at the U.S. Naval Observatory gives a parallax and distance of 30.86 ± 0.25 pc and a tangential velocity of 98 km s{sup –1}, and reveals binary orbital motion. The orbital parameters are determined from astrometry of the photocenter over more than three orbits of the 4.0 yr period. High-resolution imaging at the Keck Observatory resolves the pair with a separation of 31 and 124 mas at two epochs. Optical and near-IR photometry give a set of possible binary components. Consistency of all data indicates that the binary is a pair of DA stars with temperatures near 8000 and 7400 K and with masses of 0.93 and 0.91 M {sub ☉}; also possible is a DA primary and a helium DC secondary with temperatures near 8800 and 6000 K and with masses of 0.98 and 0.69 M {sub ☉}. In either case, the cooling ages of the stars are ∼3 Gyr and the total ages are <4 Gyr. The combined mass of the binary (1.66-1.84 M {sub ☉}) is well above the Chandrasekhar limit; however, the timescale for coalescence is long.

Target Antigen Density Governs the Efficacy of Anti-CD20-CD28-CD3 zeta Chimeric Antigen Receptor-Modified Effector CD8(+) T Cells

NARCIS (Netherlands)

Watanabe, Keisuke; Terakura, Seitaro; Martens, Anton C.; van Meerten, Tom; Uchiyama, Susumu; Imai, Misa; Sakemura, Reona; Goto, Tatsunori; Hanajiri, Ryo; Imahashi, Nobuhiko; Shimada, Kazuyuki; Tomita, Akihiro; Kiyoi, Hitoshi; Nishida, Tetsuya; Naoe, Tomoki; Murata, Makoto

2015-01-01

The effectiveness of chimeric Ag receptor (CAR)-transduced T (CAR-T) cells has been attributed to supraphysiological signaling through CARs. Second-and later-generation CARs simultaneously transmit costimulatory signals with CD3 zeta signals upon ligation, but may lead to severe adverse effects

Binary and Millisecond Pulsars

Directory of Open Access Journals (Sweden)

Lorimer Duncan R.

2005-11-01

Full Text Available We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1700. There are now 80 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 103 pulsars in 24 of the Galactic globular clusters. Recent highlights have been the discovery of the first ever double pulsar system and a recent flurry of discoveries in globular clusters, in particular Terzan 5.

Eclipsing binary stars with a δ Scuti component

Science.gov (United States)

Kahraman Aliçavuş, F.; Soydugan, E.; Smalley, B.; Kubát, J.

2017-09-01

Eclipsing binaries with a δ Sct component are powerful tools to derive the fundamental parameters and probe the internal structure of stars. In this study, spectral analysis of six primary δ Sct components in eclipsing binaries has been performed. Values of Teff, v sin I, and metallicity for the stars have been derived from medium-resolution spectroscopy. Additionally, a revised list of δ Sct stars in eclipsing binaries is presented. In this list, we have only given the δ Sct stars in eclipsing binaries to show the effects of the secondary components and tidal-locking on the pulsations of primary δ Sct components. The stellar pulsation, atmospheric and fundamental parameters (e.g. mass, radius) of 92 δ Sct stars in eclipsing binaries have been gathered. Comparison of the properties of single and eclipsing binary member δ Sct stars has been made. We find that single δ Sct stars pulsate in longer periods and with higher amplitudes than the primary δ Sct components in eclipsing binaries. The v sin I of δ Sct components is found to be significantly lower than that of single δ Sct stars. Relationships between the pulsation periods, amplitudes and stellar parameters in our list have been examined. Significant correlations between the pulsation periods and the orbital periods, Teff, log g, radius, mass ratio, v sin I and the filling factor have been found.

Tidal Disruption of Inclined or Eccentric Binaries by Massive Black Holes

Science.gov (United States)

Brown, Harriet; Kobayashi, Shiho; Rossi, Elena M.; Sari, Re'em

2018-04-01

Binary stars that are on close orbits around massive black holes (MBH) such as Sgr A* in the centre of the Milky Way are liable to undergo tidal disruption and eject a hypervelocity star. We study the interaction between such a MBH and circular binaries for general binary orientations and penetration depths (i.e. binaries penetrate into the tidal radius around the BH). We show that for very deep penetrators, almost all binaries are disrupted when the binary rotation axis is roughly oriented toward the BH or it is in the opposite direction. The surviving chance becomes significant when the angle between the binary rotation axis and the BH direction is between 0.15π and 0.85π. The surviving chance is as high as ˜20% when the binary rotation axis is perpendicular to the BH direction. However, for shallow penetrators, the highest disruption chance is found in such a perpendicular case, especially in the prograde case. This is because the dynamics of shallow penetrators is more sensitive to the relative orientation of the binary and orbital angular momenta. We provide numerical fits to the disruption probability and energy gain at the the BH encounter as a function of the penetration depth. The latter can be simply rescaled in terms of binary masses, their initial separation and the binary-to-BH mass ratio to evaluate the ejection velocity of a binary members in various systems. We also investigate the disruption of coplanar, eccentric binaries by a MBH. It is shown that for highly eccentric binaries retrograde orbits have a significantly increased disruption probability and ejection velocities compared to the circular binaries.

Evolution of binaries with compact objects in globular clusters

OpenAIRE

Ivanova, Natalia

2017-01-01

Dynamical interactions that take place between objects in dense stellar systems lead to frequent formation of exotic stellar objects, unusual binaries, and systems of higher multiplicity. They are most important for the formation of binaries with neutron stars and black holes, which are usually observationally revealed in mass-transferring binaries. Here we review the current understanding of compact object's retention, of the metallicity dependence on the formation of low-mass X-ray binaries...

Non-Binary Protograph-Based LDPC Codes: Analysis,Enumerators and Designs

OpenAIRE

Sun, Yizeng

2013-01-01

Non-binary LDPC codes can outperform binary LDPC codes using sum-product algorithm with higher computation complexity. Non-binary LDPC codes based on protographs have the advantage of simple hardware architecture. In the first part of this thesis, we will use EXIT chart analysis to compute the thresholds of different protographs over GF(q). Based on threshold computation, some non-binary protograph-based LDPC codes are designed and their frame error rates are compared with binary LDPC codes. ...

Reconciliation with non-binary species trees.

Science.gov (United States)

Vernot, Benjamin; Stolzer, Maureen; Goldman, Aiton; Durand, Dannie

2008-10-01

Reconciliation extracts information from the topological incongruence between gene and species trees to infer duplications and losses in the history of a gene family. The inferred duplication-loss histories provide valuable information for a broad range of biological applications, including ortholog identification, estimating gene duplication times, and rooting and correcting gene trees. While reconciliation for binary trees is a tractable and well studied problem, there are no algorithms for reconciliation with non-binary species trees. Yet a striking proportion of species trees are non-binary. For example, 64% of branch points in the NCBI taxonomy have three or more children. When applied to non-binary species trees, current algorithms overestimate the number of duplications because they cannot distinguish between duplication and incomplete lineage sorting. We present the first algorithms for reconciling binary gene trees with non-binary species trees under a duplication-loss parsimony model. Our algorithms utilize an efficient mapping from gene to species trees to infer the minimum number of duplications in O(|V(G) | x (k(S) + h(S))) time, where |V(G)| is the number of nodes in the gene tree, h(S) is the height of the species tree and k(S) is the size of its largest polytomy. We present a dynamic programming algorithm which also minimizes the total number of losses. Although this algorithm is exponential in the size of the largest polytomy, it performs well in practice for polytomies with outdegree of 12 or less. We also present a heuristic which estimates the minimal number of losses in polynomial time. In empirical tests, this algorithm finds an optimal loss history 99% of the time. Our algorithms have been implemented in NOTUNG, a robust, production quality, tree-fitting program, which provides a graphical user interface for exploratory analysis and also supports automated, high-throughput analysis of large data sets.

Influence of non-binary effects on intranuclear cascade method

International Nuclear Information System (INIS)

Gomes, E.H.C.

1985-01-01

The importance of non binary process effects in the intranuclear cascade method is analysed. It is shown that, in the higher density steps, the non binary collisions lead to baryon density distribution and rapidity differents from the one obtained using the usual intranuclear cascade method (limited to purely binary collisions). The validity of the applications of binary intranuclear cascade method to the simulation of the thermal equilibrium, nuclear transparency and particle production, is discussed. (M.C.K.) [pt

THE CLOSE BINARY FRACTION OF DWARF M STARS

International Nuclear Information System (INIS)

Clark, Benjamin M.; Blake, Cullen H.; Knapp, Gillian R.

2012-01-01

We describe a search for close spectroscopic dwarf M star binaries using data from the Sloan Digital Sky Survey to address the question of the rate of occurrence of multiplicity in M dwarfs. We use a template-fitting technique to measure radial velocities from 145,888 individual spectra obtained for a magnitude-limited sample of 39,543 M dwarfs. Typically, the three or four spectra observed for each star are separated in time by less than four hours, but for ∼17% of the stars, the individual observations span more than two days. In these cases we are sensitive to large-amplitude radial velocity variations on timescales comparable to the separation between the observations. We use a control sample of objects having observations taken within a four-hour period to make an empirical estimate of the underlying radial velocity error distribution and simulate our detection efficiency for a wide range of binary star systems. We find the frequency of binaries among the dwarf M stars with a < 0.4 AU to be 3%-4%. Comparison with other samples of binary stars demonstrates that the close binary fraction, like the total binary fraction, is an increasing function of primary mass.

THE CLOSE BINARY FRACTION OF DWARF M STARS

Energy Technology Data Exchange (ETDEWEB)

Clark, Benjamin M. [Penn Manor High School, 100 East Cottage Avenue, Millersville, PA 17551 (United States); Blake, Cullen H.; Knapp, Gillian R. [Princeton University, Department of Astrophysical Sciences, Peyton Hall, Ivy Lane, Princeton, NJ 08544 (United States)

2012-01-10

We describe a search for close spectroscopic dwarf M star binaries using data from the Sloan Digital Sky Survey to address the question of the rate of occurrence of multiplicity in M dwarfs. We use a template-fitting technique to measure radial velocities from 145,888 individual spectra obtained for a magnitude-limited sample of 39,543 M dwarfs. Typically, the three or four spectra observed for each star are separated in time by less than four hours, but for {approx}17% of the stars, the individual observations span more than two days. In these cases we are sensitive to large-amplitude radial velocity variations on timescales comparable to the separation between the observations. We use a control sample of objects having observations taken within a four-hour period to make an empirical estimate of the underlying radial velocity error distribution and simulate our detection efficiency for a wide range of binary star systems. We find the frequency of binaries among the dwarf M stars with a < 0.4 AU to be 3%-4%. Comparison with other samples of binary stars demonstrates that the close binary fraction, like the total binary fraction, is an increasing function of primary mass.

Binary Cockroach Swarm Optimization for Combinatorial Optimization Problem

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Ibidun Christiana Obagbuwa

2016-09-01

Full Text Available The Cockroach Swarm Optimization (CSO algorithm is inspired by cockroach social behavior. It is a simple and efficient meta-heuristic algorithm and has been applied to solve global optimization problems successfully. The original CSO algorithm and its variants operate mainly in continuous search space and cannot solve binary-coded optimization problems directly. Many optimization problems have their decision variables in binary. Binary Cockroach Swarm Optimization (BCSO is proposed in this paper to tackle such problems and was evaluated on the popular Traveling Salesman Problem (TSP, which is considered to be an NP-hard Combinatorial Optimization Problem (COP. A transfer function was employed to map a continuous search space CSO to binary search space. The performance of the proposed algorithm was tested firstly on benchmark functions through simulation studies and compared with the performance of existing binary particle swarm optimization and continuous space versions of CSO. The proposed BCSO was adapted to TSP and applied to a set of benchmark instances of symmetric TSP from the TSP library. The results of the proposed Binary Cockroach Swarm Optimization (BCSO algorithm on TSP were compared to other meta-heuristic algorithms.

A binary mixture operated heat pump

International Nuclear Information System (INIS)

Hihara, E.; Saito, T.

1991-01-01

This paper evaluates the performance of possible binary mixtures as working fluids in high- temperature heat pump applications. The binary mixtures, which are potential alternatives of fully halogenated hydrocarbons, include HCFC142b/HCFC22, HFC152a/HCFC22, HFC134a/HCFC22. The performance of the mixtures is estimated by a thermodynamic model and a practical model in which the heat transfer is considered in heat exchangers. One of the advantages of binary mixtures is a higher coefficient of performance, which is caused by the small temperature difference between the heat-sink/-source fluid and the refrigerant. The mixture HCFC142b/HCFC22 is promising from the stand point of thermodynamic performance

Wide- and contact-binary formation in substructured young stellar clusters

Science.gov (United States)

Dorval, J.; Boily, C. M.; Moraux, E.; Roos, O.

2017-02-01

We explore with collisional gravitational N-body models the evolution of binary stars in initially fragmented and globally subvirial clusters of stars. Binaries are inserted in the (initially) clumpy configurations so as to match the observed distributions of the field-binary-stars' semimajor axes a and binary fraction versus primary mass. The dissolution rate of wide binaries is very high at the start of the simulations, and is much reduced once the clumps are eroded by the global infall. The transition between the two regimes is sharper as the number of stars N is increased, from N = 1.5 k up to 80 k. The fraction of dissolved binary stars increases only mildly with N, from ≈15 per cent to ≈25 per cent for the same range in N. We repeated the calculation for two initial system mean number densities of 6 per pc3 (low) and 400 per pc3 (high). We found that the longer free-fall time of the low-density runs allows for prolonged binary-binary interactions inside clumps and the formation of very tight (a ≈ 0.01 au) binaries by exchange collisions. This is an indication that the statistics of such compact binaries bear a direct link to their environment at birth. We also explore the formation of wide (a ≳ 5 × 104 au) binaries and find a low (≈0.01 per cent) fraction mildly bound to the central star cluster. The high-precision astrometric mission Gaia could identify them as outflowing shells or streams.

Artificial neural networks using complex numbers and phase encoded weights.

Science.gov (United States)

Michel, Howard E; Awwal, Abdul Ahad S

2010-04-01

The model of a simple perceptron using phase-encoded inputs and complex-valued weights is proposed. The aggregation function, activation function, and learning rule for the proposed neuron are derived and applied to Boolean logic functions and simple computer vision tasks. The complex-valued neuron (CVN) is shown to be superior to traditional perceptrons. An improvement of 135% over the theoretical maximum of 104 linearly separable problems (of three variables) solvable by conventional perceptrons is achieved without additional logic, neuron stages, or higher order terms such as those required in polynomial logic gates. The application of CVN in distortion invariant character recognition and image segmentation is demonstrated. Implementation details are discussed, and the CVN is shown to be very attractive for optical implementation since optical computations are naturally complex. The cost of the CVN is less in all cases than the traditional neuron when implemented optically. Therefore, all the benefits of the CVN can be obtained without additional cost. However, on those implementations dependent on standard serial computers, CVN will be more cost effective only in those applications where its increased power can offset the requirement for additional neurons.

An Efficient Binary Differential Evolution with Parameter Adaptation

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Dongli Jia

2013-04-01

Full Text Available Differential Evolution (DE has been applied to many scientific and engineering problems for its simplicity and efficiency. However, the standard DE cannot be used in a binary search space directly. This paper proposes an adaptive binary Differential Evolution algorithm, or ABDE, that has a similar framework as the standard DE but with an improved binary mutation strategy in which the best individual participates. To further enhance the search ability, the parameters of the ABDE are slightly disturbed in an adaptive manner. Experiments have been carried out by comparing ABDE with two binary DE variants, normDE and BDE, and the most used binary search technique, GA, on a set of 13 selected benchmark functions and the classical 0-1 knapsack problem. Results show that the ABDE performs better than, or at least comparable to, the other algorithms in terms of search ability, convergence speed, and solution accuracy.

Beyond binaries : a way forward for comparativeeducation

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Marianne Larsen

2012-09-01

Full Text Available Binary discourses shape and produce the stories we construct about the field of comparative education. In the first part of this article, I review a set of binary discourses that have characterized social science research since the Enlightenment, including: quantitative-qualitative, nomotheticidiographic, inductive-deductive, and practice-theory. We can think of each of these binaries at opposite ends of a set of spectrums. In the second section of the paper, I show some of the ways in which these binaries have influenced the ways that we write and talk about research within the field of comparative education. I refer to the notion of binary discourses and the productive capacity of these discourses to shape our field. I then outline some critiques of these binaries to demonstrate the inherent limitations of binary discourses, and why we need to move beyond binaries in our research, and in the histories about our field. Finally, I present some tentative conclusions on ways to get ourselves out of the trap of binary thinking.Los discursos binarios moldean y producen los argumentos que construimos sobre la disciplina de la Educación Comparada. En la primera parte de este artículo, analizo un conjunto de discursos binarios que han caracterizado la investigación en Ciencias Sociales desde la Ilustración, incluyendo la cuantitativa-cualitativa, nomotética-idiográfica, inductivadeductiva, y la práctica-teoría. Podemos pensar sobre cada uno de estos discursos binarios como argumentos en los polos de un conjunto de posibilidades. En la segunda sección del artículo, revelo algunos modos en los que estos discursos binarios han influenciado las formas a través de las cuales escribimos y analizamos la investigación en el ámbito de la Educación Comparada. Analizo la noción de discursos binarios y la capacidad productiva de estos discursos de impactar nuestra ciencia. Seguidamente expongo algunas críticas de estos discursos binarios con el

Stellar X-Ray Polarimetry

Science.gov (United States)

Swank, J.

2011-01-01

Most of the stellar end-state black holes, pulsars, and white dwarfs that are X-ray sources should have polarized X-ray fluxes. The degree will depend on the relative contributions of the unresolved structures. Fluxes from accretion disks and accretion disk corona may be polarized by scattering. Beams and jets may have contributions of polarized emission in strong magnetic fields. The Gravity and Extreme Magnetism Small Explorer (GEMS) will study the effects on polarization of strong gravity of black holes and strong magnetism of neutron stars. Some part of the flux from compact stars accreting from companion stars has been reflected from the companion, its wind, or accretion streams. Polarization of this component is a potential tool for studying the structure of the gas in these binary systems. Polarization due to scattering can also be present in X-ray emission from white dwarf binaries and binary normal stars such as RS CVn stars and colliding wind sources like Eta Car. Normal late type stars may have polarized flux from coronal flares. But X-ray polarization sensitivity is not at the level needed for single early type stars.

Grammar-Based Specification and Parsing of Binary File Formats

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William Underwood

2012-03-01

Full Text Available The capability to validate and view or play binary file formats, as well as to convert binary file formats to standard or current file formats, is critically important to the preservation of digital data and records. This paper describes the extension of context-free grammars from strings to binary files. Binary files are arrays of data types, such as long and short integers, floating-point numbers and pointers, as well as characters. The concept of an attribute grammar is extended to these context-free array grammars. This attribute grammar has been used to define a number of chunk-based and directory-based binary file formats. A parser generator has been used with some of these grammars to generate syntax checkers (recognizers for validating binary file formats. Among the potential benefits of an attribute grammar-based approach to specification and parsing of binary file formats is that attribute grammars not only support format validation, but support generation of error messages during validation of format, validation of semantic constraints, attribute value extraction (characterization, generation of viewers or players for file formats, and conversion to current or standard file formats. The significance of these results is that with these extensions to core computer science concepts, traditional parser/compiler technologies can potentially be used as a part of a general, cost effective curation strategy for binary file formats.

Comments on the evolution and origin of cataclysmic binaries

International Nuclear Information System (INIS)

Whyte, C.A.; Eggleton, P.P.

1980-01-01

Aspects of the observational data on cataclysmic binaries are discussed and possible correlations between type of behaviour and binary period are noted. A gap between 2 and 3 hr in binary periods is judged to be real. A simple numerical procedure for evolving Roche-lobe-filling stars is described, and applied to white dwarf-red dwarf binaries for various mass loss and angular momentum loss mechanisms, and initial conditions. The results, in which the short-time-scale behaviour of the systems is ignored, are classified into four modes of evolution: normal, nuclear evolution dominated, angular momentum loss dominated and hydrodynamical. The clustering below 2 hr is interpreted in terms of evolution following the hydrodynamical mode, and it is suggested that both stars in such systems are of low mass. This may be the commonest type of cataclysmic binary. A possible explanation for the apparent clustering of classical novae to periods of 3 to 5 hr is given, and evolutionary schemes for cataclysmic binaries outlined. It is suggested that the short-period systems (approximately < 2 hr) arise mainly from late case B mass transfer in the original binary and the longer period systems mainly from case C. (author)

Non-binary or genderqueer genders

OpenAIRE

Richards, Christina; Bouman, Walter Pierre; Seal, Leighton; Barker, Meg John; Nieder, Timo O; T'Sjoen, Guy

2016-01-01

Some people have a gender which is neither male nor female and may identify as both male and female at one time, as different genders at different times, as no gender at all, or dispute the very idea of only two genders. The umbrella terms for such genders are genderqueer' or non-binary' genders. Such gender identities outside of the binary of female and male are increasingly being recognized in legal, medical and psychological systems and diagnostic classifications in line with the emerging ...

Prince of zeta by Petar Konjović: Opera in five/four acts on the 125th anniversary of the composer's birth

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Mosusova Nadežda

2008-01-01

Full Text Available Petar Konjović (Čurug, May 5, 1883 - Belgrade, October 1, 1970 stands out among Serbian composers as an author of instrumental and vocal compositions. Studies at the Prague Conservatory (1904-1906 acquainted Konjović with Czech music, Wagner's opus, and the Russian national-romantic school, which contributed to the evolution of his talent for both music and stage, enabling him to express his ideas more explicitly in operatic works. It was in the Prague that the second opera - Prince of Zeta - was conceived, with new musical vividness and dramatic appeal (first version composed 1906-1926, the second and final 1929-1939, followed by Koštana (1928, Peasants (1951 and Fatherland (1960. Konjović's mature operas are characterized by his masterful handling of form, both in close-ups and in detail, as well as his deeply individual assimilation of musical folklore into his work. The Prince of Zeta is not to be understood as a folk opera, but some main themes are directly derived from folk music, precisely from the Montenegrin folk songs quoted in the Mokranjac's Ninth Garland and treated in Konjović's post-romantic, almost expressionistic way, interwoven with some Italianate leitmotifs, so as to present the opera's two worlds, Montenegrin and Venetian. In the process of forming Konjović's operatic style, with vocal parts based mainly on the principle of declamation, the opera Prince of Zeta (first performed in Belgrade, 1929, conducted by Lovro von Matačić proved to be a work of great impact. Hardly anyone grasped then the wide sweep of inspiration which allowed the composer to set and to solve several important problems connected with music drama, essential also in his subsequent stage works. First of all, Konjović had to handle in his own way the verbal drama the prototype of his opera, Maxim Crnojević by the Serbian poet Laza Kostić (1841-1910. Permission came from the playwright in the first decade of the 1900, Prince of Zeta being partly

Statistical Analysis of a Comprehensive List of Visual Binaries

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Kovaleva D.

2015-12-01

Full Text Available Visual binary stars are the most abundant class of observed binaries. The most comprehensive list of data on visual binaries compiled recently by cross-matching the largest catalogues of visual binaries allowed a statistical investigation of observational parameters of these systems. The dataset was cleaned by correcting uncertainties and misclassifications, and supplemented with available parallax data. The refined dataset is free from technical biases and contains 3676 presumably physical visual pairs of luminosity class V with known angular separations, magnitudes of the components, spectral types, and parallaxes. We also compiled a restricted sample of 998 pairs free from observational biases due to the probability of binary discovery. Certain distributions of observational and physical parameters of stars of our dataset are discussed.

Main Memory Implementations for Binary Grouping

OpenAIRE

May, Norman; Moerkotte, Guido

2005-01-01

An increasing number of applications depend on efficient storage and analysis features for XML data. Hence, query optimization and efficient evaluation techniques for the emerging XQuery standard become more and more important. Many XQuery queries require nested expressions. Unnesting them often introduces binary grouping. We introduce several algorithms implementing binary grouping and analyze their time and space complexity. Experiments demonstrate their performance.

Distinguishing Between Formation Channels for Binary Black Holes with LISA

Science.gov (United States)

Breivik, Katelyn; Rodriguez, Carl L.; Larson, Shane L.; Kalogera, Vassiliki; Rasio, Frederic A.

2017-01-01

The recent detections of GW150914 and GW151226 imply an abundance of stellar-mass binary-black-hole mergers in the local universe. While ground-based gravitational-wave detectors are limited to observing the final moments before a binary merges, space-based detectors, such as the Laser Interferometer Space Antenna (LISA), can observe binaries at lower orbital frequencies where such systems may still encode information about their formation histories. In particular, the orbital eccentricity and mass of binary black holes in the LISA frequency band can be used together to discriminate between binaries formed in isolation in galactic fields and those formed in dense stellar environments such as globular clusters. In this letter, we explore the orbital eccentricity and mass of binary-black-hole populations as they evolve through the LISA frequency band. Overall we find that there are two distinct populations discernible by LISA. We show that up to ~90% of binaries formed either dynamically or in isolation have eccentricities measurable by LISA. Finally, we note how measured eccentricities of low-mass binary black holes evolved in isolation could provide detailed constraints on the physics of black-hole natal kicks and common-envelope evolution.

Optical three-step binary-logic-gate-based MSD arithmetic

Science.gov (United States)

Fyath, R. S.; Alsaffar, A. A. W.; Alam, M. S.

2003-11-01

A three-step modified signed-digit (MSD) adder is proposed which can be optically implmented using binary logic gates. The proposed scheme depends on encoding each MSD digits into a pair of binary digits using a two-state and multi-position based encoding scheme. The design algorithm depends on constructing the addition truth table of binary-coded MSD numbers and then using Karnaugh map to achieve output minimization. The functions associated with the optical binary logic gates are achieved by simply programming the decoding masks of an optical shadow-casting logic system.

The cool surfaces of binary near-Earth asteroids

Science.gov (United States)

Delbo, Marco; Walsh, Kevin; Mueller, Michael; Harris, Alan W.; Howell, Ellen S.

2011-03-01

Here we show results from thermal-infrared observations of km-sized binary near-Earth asteroids (NEAs). We combine previously published thermal properties for NEAs with newly derived values for three binary NEAs. The η value derived from the near-Earth asteroid thermal model (NEATM) for each object is then used to estimate an average thermal inertia for the population of binary NEAs and compared against similar estimates for the population of non-binaries. We find that these objects have, in general, surface temperatures cooler than the average values for non-binary NEAs as suggested by elevated η values. We discuss how this may be evidence of higher-than-average surface thermal inertia. This latter physical parameter is a sensitive indicator of the presence or absence of regolith: bodies covered with fine regolith, such as the Earth’s moon, have low thermal inertia, whereas a surface with little or no regolith displays high thermal inertia. Our results are suggestive of a binary formation mechanism capable of altering surface properties, possibly removing regolith: an obvious candidate is the YORP effect. We present also newly determined sizes and geometric visible albedos derived from thermal-infrared observations of three binary NEAs: (5381) Sekhmet, (153591) 2001 SN263, and (164121) 2003 YT1. The diameters of these asteroids are 1.41 ± 0.21 km, 1.56 ± 0.31 km, and 2.63 ± 0.40 km, respectively. Their albedos are 0.23 ± 0.13, 0.24 ± 0.16, and 0.048 ± 0.015, respectively.

Results of charpy V-notch impact testing of structural steel specimens irradiated at ∼30 degrees C to 1 x 1016 neutrons/cm2 in a commercial reactor cavity

International Nuclear Information System (INIS)

Iskander, S.K.; Stoller, R.E.

1997-04-01

A capsule containing Charpy V-notch (CVN) and mini-tensile specimens was irradiated at ∼ 30 degrees C (∼ 85 degrees F) in the cavity of a commercial nuclear power plant to a fluence of 1 x 10 16 neutrons/cm 2 (> 1MeV). The capsule included six CVN impact specimens of archival High Flux Isotope Reactor A212 grade B ferritic steel and five CVN impact specimens of a well-studied A36 structural steel. This irradiation was part of the ongoing study of neutron-induced damage effects at the low temperature and flux experienced by reactor supports. The plant operators shut down the plant before the planned exposure was reached. The exposure of these specimens produced no significant irradiation-induced embrittlement. Of interest were the data on unirradiated specimens in the L-T orientation machined from a single plate of A36 structural steel, which is the same specification for the structural steel used in some reactor supports. The average CVN energy of five unirradiated specimens obtained from one region of the plate and tested at room temperature was ∼ 99 J, while the energy of 11 unirradiated specimens from other locations of the same plate was 45 J, a difference of ∼ 220%. The CVN impact energies for all 18 specimens ranged from a low of 32 J to a high of 111 J. Moreover, it appears that the University of Kansas CVN impact energy data of the unirradiated specimens at the 100-J level are shifted toward higher temperatures by about 20 K. The results were an example of the extent of scatter possible in CVN impact testing. Generic values for the CVN impact energy of A36 should be used with caution in critical applications

Dynamic Inertia Weight Binary Bat Algorithm with Neighborhood Search

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Xingwang Huang

2017-01-01

Full Text Available Binary bat algorithm (BBA is a binary version of the bat algorithm (BA. It has been proven that BBA is competitive compared to other binary heuristic algorithms. Since the update processes of velocity in the algorithm are consistent with BA, in some cases, this algorithm also faces the premature convergence problem. This paper proposes an improved binary bat algorithm (IBBA to solve this problem. To evaluate the performance of IBBA, standard benchmark functions and zero-one knapsack problems have been employed. The numeric results obtained by benchmark functions experiment prove that the proposed approach greatly outperforms the original BBA and binary particle swarm optimization (BPSO. Compared with several other heuristic algorithms on zero-one knapsack problems, it also verifies that the proposed algorithm is more able to avoid local minima.

Asymmetric supernova explosions and the origin of binary pulsars

International Nuclear Information System (INIS)

Sutantyo, W.

1978-01-01

The author investigates the effect of asymmetric supernova explosions on the orbital parameters of binary systems with a compact component. Such explosions are related to the origin of binary pulsars. The degree of asymmetry of the explosion is represented by the kick velocity gained by the exploding star due to the asymmetric mass ejection. The required kick velocity to produce the observed parameters of the binary pulsar PSR 1913 + 16 should be larger than approximately 80 km s -1 if the mass of the exploding star is larger than approximately 4 solar masses. The mean survival probability of the binary system ( ) is examined for various degrees of asymmetry in the explosion. The rare occurrence of a binary pulsar does not neccessarily imply that such a probability is low since not all pulsars have originated in a binary system. Assuming the birth rate of pulsars by Taylor and Manchester (1977), it is derived that would be as high as 0.25. Such values of can be obtained if the mass of the exploding stars is, in general, not large (< approximately 10 solar masses). (Auth.)

General simulation algorithm for autocorrelated binary processes.

Science.gov (United States)

Serinaldi, Francesco; Lombardo, Federico

2017-02-01

The apparent ubiquity of binary random processes in physics and many other fields has attracted considerable attention from the modeling community. However, generation of binary sequences with prescribed autocorrelation is a challenging task owing to the discrete nature of the marginal distributions, which makes the application of classical spectral techniques problematic. We show that such methods can effectively be used if we focus on the parent continuous process of beta distributed transition probabilities rather than on the target binary process. This change of paradigm results in a simulation procedure effectively embedding a spectrum-based iterative amplitude-adjusted Fourier transform method devised for continuous processes. The proposed algorithm is fully general, requires minimal assumptions, and can easily simulate binary signals with power-law and exponentially decaying autocorrelation functions corresponding, for instance, to Hurst-Kolmogorov and Markov processes. An application to rainfall intermittency shows that the proposed algorithm can also simulate surrogate data preserving the empirical autocorrelation.

Mass loss from interacting close binary systems

Science.gov (United States)

Plavec, M. J.

1981-01-01

The three well-defined classes of evolved binary systems that show evidence of present and/or past mass loss are the cataclysmic variables, the Algols, and Wolf-Rayet stars. It is thought that the transformation of supergiant binary systems into the very short-period cataclysmic variables must have been a complex process. The new evidence that has recently been obtained from the far ultraviolet spectra that a certain subclass of the Algols (the Serpentids) are undergoing fairly rapid evolution is discussed. It is thought probable that the remarkable mass outflow observed in them is connected with a strong wind powered by accretion. The origin of the circumbinary clouds or flat disks that probably surround many strongly interacting binaries is not clear. Attention is also given to binary systems with hot white dwarf or subdwarf components, such as the symbiotic objects and the BQ stars; it is noted that in them both components may be prone to an enhanced stellar wind.

General simulation algorithm for autocorrelated binary processes

Science.gov (United States)

Serinaldi, Francesco; Lombardo, Federico

2017-02-01

The apparent ubiquity of binary random processes in physics and many other fields has attracted considerable attention from the modeling community. However, generation of binary sequences with prescribed autocorrelation is a challenging task owing to the discrete nature of the marginal distributions, which makes the application of classical spectral techniques problematic. We show that such methods can effectively be used if we focus on the parent continuous process of beta distributed transition probabilities rather than on the target binary process. This change of paradigm results in a simulation procedure effectively embedding a spectrum-based iterative amplitude-adjusted Fourier transform method devised for continuous processes. The proposed algorithm is fully general, requires minimal assumptions, and can easily simulate binary signals with power-law and exponentially decaying autocorrelation functions corresponding, for instance, to Hurst-Kolmogorov and Markov processes. An application to rainfall intermittency shows that the proposed algorithm can also simulate surrogate data preserving the empirical autocorrelation.

The Discovery of the Most Accelerated Binary Pulsar

OpenAIRE

Cameron, A. D.; Champion, D. J.; Kramer, M.; Bailes, M.; Barr, E. D.; Bassa, C. G.; Bhandari, S.; Bhat, N. D. R.; Burgay, M.; Burke-Spolaor, S.; Eatough, R. P.; Flynn, C. M. L.; Freire, P. C. C.; Jameson, A.; Johnston, S.

2018-01-01

Pulsars in relativistic binary systems have emerged as fantastic natural laboratories for testing theories of gravity, the most prominent example being the double pulsar, PSR J0737$-$3039. The HTRU-South Low Latitude pulsar survey represents one of the most sensitive blind pulsar surveys taken of the southern Galactic plane to date, and its primary aim has been the discovery of new relativistic binary pulsars. Here we present our binary pulsar searching strategy and report on the survey's fla...

Shrinking of Binaries in a WIMPY Background at the Galactic Center

Science.gov (United States)

Hills, J. G.

2001-12-01

The nature of the dark matter in the Galactic Halo is still not clear. Constraints can be placed on it; e.g., it cannot be in baryons less massive than about 1022 grams (Hills, 1986, Astron. J. 92, 595). It may be in elementary weakly interacting massive particles, WIMPS. Apart from providing most of the mass of the Galaxy, the only known significant dynamical effect of WIMPS is to cause a gradual shrinking of tightly bound binaries (Hills 1983, Astron. J. 88, 1269) as they interact with the background soup of WIMPS. This effect may be observable in binaries close to the Galactic Center if a significant fraction of the mass density near the central black hole is from WIMPS. The requisite binaries would have to have orbital velocities greater than the local velocity dispersion of the WIMPS relative to the binary. The velocity dispersion increases near the black hole. The binary cannot be too close to the black hole or its tidal field will breakup the binary. If the local WIMP density is 107 g/cm3, the fractional rate of reduction in the binary orbital period is about 5 x 10-10/yr for a binary having a semimajor axis equal to 3 solar radii in a soup of WIMPS having a velocity dispersion of 200 km/s relative to the binary. This gradual erosion of the binary period may be detectable, particularly, if one of the binary components is a pulsar.

Optimized reversible binary-coded decimal adders

DEFF Research Database (Denmark)

Thomsen, Michael Kirkedal; Glück, Robert

2008-01-01

Abstract Babu and Chowdhury [H.M.H. Babu, A.R. Chowdhury, Design of a compact reversible binary coded decimal adder circuit, Journal of Systems Architecture 52 (5) (2006) 272-282] recently proposed, in this journal, a reversible adder for binary-coded decimals. This paper corrects and optimizes...... their design. The optimized 1-decimal BCD full-adder, a 13 × 13 reversible logic circuit, is faster, and has lower circuit cost and less garbage bits. It can be used to build a fast reversible m-decimal BCD full-adder that has a delay of only m + 17 low-power reversible CMOS gates. For a 32-decimal (128-bit....... Keywords: Reversible logic circuit; Full-adder; Half-adder; Parallel adder; Binary-coded decimal; Application of reversible logic synthesis...

PROSPECTS FOR DETECTING ASTEROSEISMIC BINARIES IN KEPLER DATA

Energy Technology Data Exchange (ETDEWEB)

Miglio, A.; Chaplin, W. J.; Elsworth, Y.; Handberg, R. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Farmer, R.; Kolb, U. [Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Girardi, L. [INAF-Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Appourchaux, T. [Institut d' Astrophysique Spatiale, UMR8617, Université Paris XI, Bâtiment 121, F-91405 Orsay Cedex (France)

2014-03-20

Asteroseismology may in principle be used to detect unresolved stellar binary systems comprised of solar-type stars and/or red giants. This novel method relies on the detection of the presence of two solar-like oscillation spectra in the frequency spectrum of a single light curve. Here, we make predictions of the numbers of systems that may be detectable in data already collected by the NASA Kepler Mission. Our predictions, which are based upon TRILEGAL and BiSEPS simulations of the Kepler field of view, indicate that as many as 200 or more ''asteroseismic binaries'' may be detectable in this manner. Most of these binaries should be comprised of two He-core-burning red giants. Owing largely to the limited numbers of targets with the requisite short-cadence Kepler data, we expect only a small number of detected binaries containing solar-type stars. The predicted yield of detections is sensitive to the assumed initial mass ratio distribution (IMRD) of the binary components and therefore represents a sensitive calibration of the much debated IMRD near mass ratio unity.

FORMATION OF BLACK HOLE X-RAY BINARIES IN GLOBULAR CLUSTERS

International Nuclear Information System (INIS)

Ivanova, N.; Heinke, C. O.; Woods, T. E.; Chaichenets, S.; Fregeau, J.; Lombardi, J. C.

2010-01-01

Inspired by the recent identification in extragalactic globular clusters of the first candidate black hole-white dwarf (BH-WD) X-ray binaries, where the compact accretors may be stellar-mass black holes (BHs), we explore how such binaries could be formed in a dynamical environment. We provide analyses of the formation rates via well-known formation channels like binary exchange and physical collisions and propose that the only possibility of forming BH-WD binaries is via coupling these usual formation channels with subsequent hardening and/or triple formation. In particular, we find that the most important mechanism for the creation of a BH-WD X-ray binary from an initially dynamically formed BH-WD binary is mass transfer induced in a triple system via the Kozai mechanism. Furthermore, we find that BH-WD binaries that evolve into X-ray sources can be formed by exchanges of a BH into a WD-WD binary or possibly by collisions of a BH and a giant star. If BHs undergo significant evaporation from the cluster or form a completely detached subcluster of BHs, then we cannot match the observationally inferred production rates even using the most optimistic estimates of formation rates. To explain the observations with stellar-mass BH-WD binaries, at least 1% of all formed BHs, or presumably 10% of the BHs present in the core now, must be involved in interactions with the rest of the core stellar population.

Evolution in close binary systems

International Nuclear Information System (INIS)

Yungel'son, L.R.; Masevich, A.G.

1983-01-01

Duality is the property most typical of stars. If one investigates how prevalent double stars are, making due allowance for selection effects, one finds that as many as 90 percent of all stars are paired. Contrary to tradition it is single stars that are out of the ordinary, and as will be shown presently even some of these may have been formed by coalescence of the members of binary systems. This review deals with the evolution of close binaries, defined as double-star systems whose evolution entails exchange of material between the two components

The gravitational-wave memory from eccentric binaries

International Nuclear Information System (INIS)

Favata, Marc

2011-01-01

The nonlinear gravitational-wave memory causes a time-varying but nonoscillatory correction to the gravitational-wave polarizations. It arises from gravitational-waves that are sourced by gravitational-waves. Previous considerations of the nonlinear memory effect have focused on quasicircular binaries. Here I consider the nonlinear memory from Newtonian orbits with arbitrary eccentricity. Expressions for the waveform polarizations and spin-weighted spherical-harmonic modes are derived for elliptic, hyperbolic, parabolic, and radial orbits. In the hyperbolic, parabolic, and radial cases the nonlinear memory provides a 2.5 post-Newtonian (PN) correction to the leading-order waveforms. This is in contrast to the elliptical and quasicircular cases, where the nonlinear memory corrects the waveform at leading (0PN) order. This difference in PN order arises from the fact that the memory builds up over a short ''scattering'' time scale in the hyperbolic case, as opposed to a much longer radiation-reaction time scale in the elliptical case. The nonlinear memory corrections presented here complete our knowledge of the leading-order (Peters-Mathews) waveforms for elliptical orbits. These calculations are also relevant for binaries with quasicircular orbits in the present epoch which had, in the past, large eccentricities. Because the nonlinear memory depends sensitively on the past evolution of a binary, I discuss the effect of this early-time eccentricity on the value of the late-time memory in nearly circularized binaries. I also discuss the observability of large ''memory jumps'' in a binary's past that could arise from its formation in a capture process. Lastly, I provide estimates of the signal-to-noise ratio of the linear and nonlinear memories from hyperbolic and parabolic binaries.

Proposed experiment to test fundamentally binary theories

Science.gov (United States)

Kleinmann, Matthias; Vértesi, Tamás; Cabello, Adán

2017-09-01

Fundamentally binary theories are nonsignaling theories in which measurements of many outcomes are constructed by selecting from binary measurements. They constitute a sensible alternative to quantum theory and have never been directly falsified by any experiment. Here we show that fundamentally binary theories are experimentally testable with current technology. For that, we identify a feasible Bell-type experiment on pairs of entangled qutrits. In addition, we prove that, for any n , quantum n -ary correlations are not fundamentally (n -1 ) -ary. For that, we introduce a family of inequalities that hold for fundamentally (n -1 ) -ary theories but are violated by quantum n -ary correlations.

Coalescence of Black Hole-Neutron Star Binaries

Directory of Open Access Journals (Sweden)

Masaru Shibata

2011-08-01

Full Text Available We review the current status of general relativistic studies for the coalescence of black hole-neutron star (BH-NS binaries. First, procedures for a solution of BH-NS binaries in quasi-equilibrium circular orbits and the numerical results, such as quasi-equilibrium sequence and mass-shedding limit, of the high-precision computation, are summarized. Then, the current status of numerical-relativity simulations for the merger of BH-NS binaries is described. We summarize our understanding for the merger and/or tidal disruption processes, the criterion for tidal disruption, the properties of the remnant formed after the tidal disruption, gravitational waveform, and gravitational-wave spectrum.

Dielectric properties of binary solutions a data handbook

CERN Document Server

Akhadov, Y Y

1980-01-01

Dielectric Properties of Binary Solutions focuses on the investigation of the dielectric properties of solutions, as well as the molecular interactions and mechanisms of molecular processes that occur in liquids. The book first discusses the fundamental formulas describing the dielectric properties of liquids and dielectric data for binary systems of non-aqueous solutions. Topics include permittivity and dielectric dispersion parameters of non-aqueous solutions of organic and inorganic compounds. The text also tackles dielectric data for binary systems of aqueous solutions, including permittiv

RELATIONSHIP BETWEEN FLASH POINTS OF SOME BINARY ...

African Journals Online (AJOL)

B. S. Chandravanshi

Miscellaneous binary blends containing solvent neutral-150 (SN-150), ... viscosity, the flash point test has always been a standard part of a lubricant's specification. ... between structure and flash points of organic compounds [5-12] and fuels [13, 14]. ... in binary mixtures, the gaps between flash points would be high enough.

Short-term variability of binary and non-binary Trans-Neptunian Objects

Science.gov (United States)

Thirouin, Audrey; Noll, K. S.; Campo Bagatin, A.; Ortiz Moreno, J. L.; Morales, N.

2013-10-01

Since 1992, more than 1400 Trans-Neptunian Objects (TNOs) have been discovered. Our approach to understand such objects is to study their rotations by monitoring their brightness variations. By studying the rotational properties of the TNOs a wealth of information can be obtained on their physics. So, the study of the spins and shapes of TNOs is a powerful method of gaining information on the formation and evolution of our Solar System. We have observed most of the brightest TNOs and centaurs, and compiled one of the largest lightcurves samples. The main purpose was to increase the number of objects whose short-term variability has been studied and present a homogeneous dataset trying to avoid observational biases. A dataset composed of 54 TNOs/Centaurs is reported and analyzed. Amplitudes and rotational periods have been derived for 45 of them with different degrees of reliability. For 9 objects, only an estimation of the amplitude is reported. Because most of the TNOs/Centaurs have low amplitude lightcurves, it is difficult to distinguish between single- and double-peaked lightcurves. Based on our results and the literature, following Binzel et al. (1989) study about asteroids rotational frequency distribution, we studied the TNOs spin rate distributions. We performed several Maxwellian fits to various histograms obtained considering that the lightcurves are single- or double-peaked. We tested lightcurve amplitude limits to distinguish if the lightcurve is albedo- or shape-dominated. Such a consideration introduces important changes in the distribution. We derived that an amplitude limit of 0.15mag gave a good fit to Maxwellian distribution. So, it seems that 0.15mag is a good measure of the typical variability caused by albedo. We studied the short-term variability of binary TNOs thanks to unresolved lightcurves. Based on our results and those from the literature, we come up with a sample of 32 systems with a rotational period and/or lightcurve amplitude value

Binary Black Hole Mergers from Globular Clusters: Implications for Advanced LIGO.

Science.gov (United States)

Rodriguez, Carl L; Morscher, Meagan; Pattabiraman, Bharath; Chatterjee, Sourav; Haster, Carl-Johan; Rasio, Frederic A

2015-07-31

The predicted rate of binary black hole mergers from galactic fields can vary over several orders of magnitude and is extremely sensitive to the assumptions of stellar evolution. But in dense stellar environments such as globular clusters, binary black holes form by well-understood gravitational interactions. In this Letter, we study the formation of black hole binaries in an extensive collection of realistic globular cluster models. By comparing these models to observed Milky Way and extragalactic globular clusters, we find that the mergers of dynamically formed binaries could be detected at a rate of ∼100 per year, potentially dominating the binary black hole merger rate. We also find that a majority of cluster-formed binaries are more massive than their field-formed counterparts, suggesting that Advanced LIGO could identify certain binaries as originating from dense stellar environments.

Kepler Eclipsing Binary Stars. I. Catalog and Principal Characterization of 1879 Eclipsing Binaries in the First Data Release

Science.gov (United States)

Prša, Andrej; Batalha, Natalie; Slawson, Robert W.; Doyle, Laurance R.; Welsh, William F.; Orosz, Jerome A.; Seager, Sara; Rucker, Michael; Mjaseth, Kimberly; Engle, Scott G.; Conroy, Kyle; Jenkins, Jon; Caldwell, Douglas; Koch, David; Borucki, William

2011-03-01

The Kepler space mission is devoted to finding Earth-size planets orbiting other stars in their habitable zones. Its large, 105 deg2 field of view features over 156,000 stars that are observed continuously to detect and characterize planet transits. Yet, this high-precision instrument holds great promise for other types of objects as well. Here we present a comprehensive catalog of eclipsing binary stars observed by Kepler in the first 44 days of operation, the data being publicly available through MAST as of 2010 June 15. The catalog contains 1879 unique objects. For each object, we provide its Kepler ID (KID), ephemeris (BJD0, P 0), morphology type, physical parameters (T eff, log g, E(B - V)), the estimate of third light contamination (crowding), and principal parameters (T 2/T 1, q, fillout factor, and sin i for overcontacts, and T 2/T 1, (R 1 + R 2)/a, esin ω, ecos ω, and sin i for detached binaries). We present statistics based on the determined periods and measure the average occurrence rate of eclipsing binaries to be ~1.2% across the Kepler field. We further discuss the distribution of binaries as a function of galactic latitude and thoroughly explain the application of artificial intelligence to obtain principal parameters in a matter of seconds for the whole sample. The catalog was envisioned to serve as a bridge between the now public Kepler data and the scientific community interested in eclipsing binary stars.

KEPLER ECLIPSING BINARY STARS. I. CATALOG AND PRINCIPAL CHARACTERIZATION OF 1879 ECLIPSING BINARIES IN THE FIRST DATA RELEASE

International Nuclear Information System (INIS)

Prsa, Andrej; Engle, Scott G.; Conroy, Kyle; Batalha, Natalie; Rucker, Michael; Mjaseth, Kimberly; Slawson, Robert W.; Doyle, Laurance R.; Welsh, William F.; Orosz, Jerome A.; Seager, Sara; Jenkins, Jon; Caldwell, Douglas; Koch, David; Borucki, William

2011-01-01

The Kepler space mission is devoted to finding Earth-size planets orbiting other stars in their habitable zones. Its large, 105 deg 2 field of view features over 156,000 stars that are observed continuously to detect and characterize planet transits. Yet, this high-precision instrument holds great promise for other types of objects as well. Here we present a comprehensive catalog of eclipsing binary stars observed by Kepler in the first 44 days of operation, the data being publicly available through MAST as of 2010 June 15. The catalog contains 1879 unique objects. For each object, we provide its Kepler ID (KID), ephemeris (BJD 0 , P 0 ), morphology type, physical parameters (T eff , log g, E(B - V)), the estimate of third light contamination (crowding), and principal parameters (T 2 /T 1 , q, fillout factor, and sin i for overcontacts, and T 2 /T 1 , (R 1 + R 2 )/a, esin ω, ecos ω, and sin i for detached binaries). We present statistics based on the determined periods and measure the average occurrence rate of eclipsing binaries to be ∼1.2% across the Kepler field. We further discuss the distribution of binaries as a function of galactic latitude and thoroughly explain the application of artificial intelligence to obtain principal parameters in a matter of seconds for the whole sample. The catalog was envisioned to serve as a bridge between the now public Kepler data and the scientific community interested in eclipsing binary stars.

Binary evolution and observational constraints

International Nuclear Information System (INIS)

Loore, C. de

1984-01-01

The evolution of close binaries is discussed in connection with problems concerning mass and angular momentum losses. Theoretical and observational evidence for outflow of matter, leaving the system during evolution is given: statistics on total masses and mass ratios, effects of the accretion of the mass gaining component, the presence of streams, disks, rings, circumstellar envelopes, period changes, abundance changes in the atmosphere. The effects of outflowing matter on the evolution is outlined, and estimates of the fraction of matter expelled by the loser, and leaving the system, are given. The various time scales involved with evolution and observation are compared. Examples of non conservative evolution are discussed. Problems related to contact phases, on mass and energy losses, in connection with entropy changes are briefly analysed. For advanced stages the disruption probabilities for supernova explosions are examined. A global picture is given for the evolution of massive close binaries, from ZAMS, through WR phases, X-ray phases, leading to runaway pulsars or to a binary pulsar and later to a millisecond pulsar. (Auth.)

X rays from radio binaries

International Nuclear Information System (INIS)

Apparao, K.M.V.

1977-01-01

Reference is made to the radio binary systems CC Cas, AR Lac, β Per (Algol), β Lyr, b Per and Cyg X-1. It is stated that a thermal interpretation of the radiation from Algol requires a much larger x-ray flux than the observed value of 3.8 x 10 -11 erg/cm 2 /sec/keV in the 2 to 6 keV energy range. Observations of some non-thermal flares, together with the small size of the radio source in Algol, indicate that the radio emission is non-thermal in nature. The radio emission is interpreted as synchrotron radiation and it is suggested that the observed x-ray emission is due to inverse Compton scattering of the light of the primary star by the radio electrons. The x-ray emission from other radio binaries is also calculated using this model. The energy for the radio electrons can arise from annihilation of magnetic lines connecting the binary stars, twisted by the rotation of the stars. (U.K.)

Binary Relations as a Foundation of Mathematics

NARCIS (Netherlands)

Kuper, Jan; Barendsen, E.; Capretta, V.; Geuvers, H.; Niqui, M.

2007-01-01

We describe a theory for binary relations in the Zermelo-Fraenkel style. We choose for ZFCU, a variant of ZFC Set theory in which the Axiom of Foundation is replaced by an axiom allowing for non-wellfounded sets. The theory of binary relations is shown to be equi-consistent ZFCU by constructing a

Eclipsing binaries observed with the WIRE satellite I. Discovery and photometric analysis of the new bright A0 IV eclipsing binary psi centauri

DEFF Research Database (Denmark)

Bruntt, Hans; Southworth, J.; Penny, A. J.

2006-01-01

Stars: fundamental parameters, binaries: close, eclipsing, techniques: photometric Udgivelsesdato: Sep.......Stars: fundamental parameters, binaries: close, eclipsing, techniques: photometric Udgivelsesdato: Sep....

Hybrid Black-Hole Binary Initial Data

Science.gov (United States)

Mundim, Bruno C.; Kelly, Bernard J.; Nakano, Hiroyuki; Zlochower, Yosef; Campanelli, Manuela

2010-01-01

"Traditional black-hole binary puncture initial data is conformally flat. This unphysical assumption is coupled with a lack of radiation signature from the binary's past life. As a result, waveforms extracted from evolutions of this data display an abrupt jump. In Kelly et al. [Class. Quantum Grav. 27:114005 (2010)], a new binary black-hole initial data with radiation contents derived in the post-Newtonian (PN) calculations was adapted to puncture evolutions in numerical relativity. This data satisfies the constraint equations to the 2.5PN order, and contains a transverse-traceless "wavy" metric contribution, violating the standard assumption of conformal flatness. Although the evolution contained less spurious radiation, there were undesired features; the unphysical horizon mass loss and the large initial orbital eccentricity. Introducing a hybrid approach to the initial data evaluation, we significantly reduce these undesired features."

ADDITIONAL MASSIVE BINARIES IN THE CYGNUS OB2 ASSOCIATION

International Nuclear Information System (INIS)

Kiminki, Daniel C.; Kobulnicky, Henry A.; Ewing, Ian; Lundquist, Michael; Alexander, Michael; Vargas-Alvarez, Carlos; Choi, Heather; Bagley Kiminki, Megan M.; Henderson, C. B.

2012-01-01

We report the discovery and orbital solutions for two new OB binaries in the Cygnus OB2 Association, MT311 (B2V + B3V) and MT605 (B0.5V + B2.5:V). We also identify the system MT429 as a probable triple system consisting of a tight eclipsing 2.97 day B3V+B6V pair and a B0V at a projected separation of 138 AU. We further provide the first spectroscopic orbital solutions to the eclipsing, double-lined, O-star binary MT696 (O9.5V + B1:V), the double-lined, early B binary MT720 (B0-1V + B1-2V), and the double-lined, O-star binary MT771 (O7V + O9V). These systems exhibit orbital periods between 1.5 days and 12.3 days, with the majority having P <6 days. The two new binary discoveries and six spectroscopic solutions bring the total number of known massive binaries in the central region of the Cygnus OB2 Association to 20, with all but two having full orbital solutions.

ADDITIONAL MASSIVE BINARIES IN THE CYGNUS OB2 ASSOCIATION

Energy Technology Data Exchange (ETDEWEB)

Kiminki, Daniel C.; Kobulnicky, Henry A.; Ewing, Ian; Lundquist, Michael; Alexander, Michael; Vargas-Alvarez, Carlos; Choi, Heather [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82070 (United States); Bagley Kiminki, Megan M. [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Henderson, C. B. [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States)

2012-03-01

We report the discovery and orbital solutions for two new OB binaries in the Cygnus OB2 Association, MT311 (B2V + B3V) and MT605 (B0.5V + B2.5:V). We also identify the system MT429 as a probable triple system consisting of a tight eclipsing 2.97 day B3V+B6V pair and a B0V at a projected separation of 138 AU. We further provide the first spectroscopic orbital solutions to the eclipsing, double-lined, O-star binary MT696 (O9.5V + B1:V), the double-lined, early B binary MT720 (B0-1V + B1-2V), and the double-lined, O-star binary MT771 (O7V + O9V). These systems exhibit orbital periods between 1.5 days and 12.3 days, with the majority having P <6 days. The two new binary discoveries and six spectroscopic solutions bring the total number of known massive binaries in the central region of the Cygnus OB2 Association to 20, with all but two having full orbital solutions.

Physics of Relativistic Objects in Compact Binaries: From Birth to Coalescence

CERN Document Server

Colpi, Monica; Gorini, Vittorio; Moschella, Ugo; Possenti, Andrea

2009-01-01

This book provides a comprehensive, authoritative and timely review of the astrophysical approach to the investigation of gravity theories. Particular attention is paid to strong-field tests of general relativity and alternative theories of gravity, performed using collapsed objects (neutron stars, black holes and white dwarfs) in relativistic binaries as laboratories. The book starts with an introduction which gives the background linking experimental gravity in cosmic laboratories to astrophysics and fundamental physics. Subsequent chapters cover observational and theoretical aspects of the following topics: from binaries as test-beds of gravity theories to binary pulsars as cosmic laboratories; from binary star evolution to the formation of relativistic binaries; from short gamma-ray bursts to low mass X-ray binaries; from stellar-mass black hole binaries to coalescing super-massive black holes in galaxy mergers. The book will be useful to researchers, PhD and graduate students in Astrophysics, Cosmology, ...

Optical studies of massive X-ray binaries

International Nuclear Information System (INIS)

Zuiderwijk, E.J.

1979-01-01

Photometric and spectroscopic studies of several optical counterparts of massive X-ray binaries are presented. Subjects of study were the binary systems:HD77581/4U0900-40 (Vela X-1), HD153919/4U1700-37, Wray 977/4U1223-62 and Sk160/4U0115-74 (=SMC X-1). (Auth.)

Binary pairs of supermassive black holes - Formation in merging galaxies

Energy Technology Data Exchange (ETDEWEB)

Valtaoja, L.; Valtonen, M.J.; Byrd, G.G. (Turku Univ. (Finland); Alabama Univ., Tuscaloosa (USA))

1989-08-01

A process in which supermassive binary blackholes are formed in nuclei of supergiant galaxies due to galaxy mergers is examined. There is growing evidence that mergers of galaxies are common and that supermassive black holes in center of galaxies are also common. Consequently, it is expected that binary black holes should arise in connection with galaxy mergers. The merger process in a galaxy modeled after M87 is considered. The capture probability of a companion is derived as a function of its mass. Assuming a correlation between the galaxy mass and the blackholes mass, the expected mass ratio in binary black holes is calculated. The binary black holes formed in this process are long lived, surviving longer than the Hubble time unless they are perturbed by black holes from successive mergers. The properties of these binaries agree with Gaskell's (1988) observational work on quasars and its interpretation in terms of binary black holes. 39 refs.

BINARIES DISCOVERED BY THE MUCHFUSS PROJECT: SDSS J08205+0008-AN ECLIPSING SUBDWARF B BINARY WITH A BROWN DWARF COMPANION

International Nuclear Information System (INIS)

Geier, S.; Schaffenroth, V.; Drechsel, H.; Heber, U.; Kupfer, T.; Tillich, A.; Oestensen, R. H.; Smolders, K.; Degroote, P.; Maxted, P. F. L.; Barlow, B. N.; Gaensicke, B. T.; Marsh, T. R.; Napiwotzki, R.

2011-01-01

Hot subdwarf B stars (sdBs) are extreme horizontal branch stars believed to originate from close binary evolution. Indeed about half of the known sdB stars are found in close binaries with periods ranging from a few hours to a few days. The enormous mass loss required to remove the hydrogen envelope of the red-giant progenitor almost entirely can be explained by common envelope ejection. A rare subclass of these binaries are the eclipsing HW Vir binaries where the sdB is orbited by a dwarf M star. Here, we report the discovery of an HW Vir system in the course of the MUCHFUSS project. A most likely substellar object (≅0.068 M sun ) was found to orbit the hot subdwarf J08205+0008 with a period of 0.096 days. Since the eclipses are total, the system parameters are very well constrained. J08205+0008 has the lowest unambiguously measured companion mass yet found in a subdwarf B binary. This implies that the most likely substellar companion has not only survived the engulfment by the red-giant envelope, but also triggered its ejection and enabled the sdB star to form. The system provides evidence that brown dwarfs may indeed be able to significantly affect late stellar evolution.

32 CFR 706.2 - Certifications of the Secretary of the Navy under Executive Order 11964 and 33 U.S.C. 1605.

Science.gov (United States)

2010-07-01

... SIDES FFG 14 1.6 USS ESTOCIN FFG 15 1.6 USS JOHN A. MOORE FFG 19 1.6 USS BOONE FFG 28 1.6 USS STEPHEN W... USS HARRY S TRUMAN CVN 75 30.02 1 1 0.56 USS RONALD REAGAN CVN 76 31.09 0.56 USS GEORGE H. W. BUSH CVN... USS ESTOCIN FFG 15 USS JOHN A. MOORE FFG 19 USS BOONE FFG 28 USS STEPHEN W. GROVES FFG 29 USS JOHN L...

Binaries traveling through a gaseous medium: dynamical drag forces and internal torques

Energy Technology Data Exchange (ETDEWEB)

Sánchez-Salcedo, F. J. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Ciudad Universitaria, Apt. Postal 70 264, C.P. 04510, Mexico City (Mexico); Chametla, Raul O., E-mail: jsanchez@astro.unam.mx [Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, UP Adolfo López Mateos, Mexico City (Mexico)

2014-10-20

Using time-dependent linear theory, we investigate the morphology of the gravitational wake induced by a binary, whose center of mass moves at velocity V{sub cm} against a uniform background of gas. For simplicity, we assume that the components of the binary are on circular orbits about their common center of mass. The consequences of dynamical friction is twofold. First, gas dynamical friction may drag the center of mass of the binary and cause the binary to migrate. Second, drag forces also induce a braking torque, which causes the orbits of the components of the binary to shrink. We compute the drag forces acting on one component of the binary due to the gravitational interaction with its own wake. We show that the dynamical friction force responsible for decelerating the center of mass of the binary is smaller than it is in the point-mass case because of the loss of gravitational focusing. We show that the braking internal torque depends on the Mach numbers of each binary component about their center of mass, and also on the Mach number of the center of mass of the binary. In general, the internal torque decreases with increasing the velocity of the binary relative to the ambient gas cloud. However, this is not always the case. We also mention the relevance of our results to the period distribution of binaries.

A DEEPLY ECLIPSING DETACHED DOUBLE HELIUM WHITE DWARF BINARY

International Nuclear Information System (INIS)

Parsons, S. G.; Marsh, T. R.; Gaensicke, B. T.; Drake, A. J.; Koester, D.

2011-01-01

Using Liverpool Telescope+RISE photometry we identify the 2.78 hr period binary star CSS 41177 as a detached eclipsing double white dwarf binary with a 21,100 K primary star and a 10,500 K secondary star. This makes CSS 41177 only the second known eclipsing double white dwarf binary after NLTT 11748. The 2 minute long primary eclipse is 40% deep and the secondary eclipse 10% deep. From Gemini+GMOS spectroscopy, we measure the radial velocities of both components of the binary from the Hα absorption line cores. These measurements, combined with the light curve information, yield white dwarf masses of M 1 = 0.283 ± 0.064 M sun and M 2 = 0.274 ± 0.034 M sun , making them both helium core white dwarfs. As an eclipsing, double-lined spectroscopic binary, CSS 41177 is ideally suited to measuring precise, model-independent masses and radii. The two white dwarfs will merge in roughly 1.1 Gyr to form a single sdB star.

Binary Biometric Representation through Pairwise Adaptive Phase Quantization

NARCIS (Netherlands)

Chen, C.; Veldhuis, Raymond N.J.

Extracting binary strings from real-valued biometric templates is a fundamental step in template compression and protection systems, such as fuzzy commitment, fuzzy extractor, secure sketch, and helper data systems. Quantization and coding is the straightforward way to extract binary representations

Diffusion in ordered binary solid systems

International Nuclear Information System (INIS)

Stolwijk, N.A.

1980-01-01

This thesis contains contributions to the field of diffusion in ordered binary solid systems. An extensive experimental investigation of the self diffusion in CoGa is presented. The results of these diffusion measurements strongly suggest that a substantial part of the atomic migration is caused by a new type of defect. A quantitative description of the atomic displacements via this defect is given. Finally computer simulations are presented of diffusion and ordering in binary solid systems. (Auth.)

An Introduction to Binary Decision Diagrams

DEFF Research Database (Denmark)

Andersen, Henrik Reif

1996-01-01

This note is a short introduction to Binary Decision Diagrams (BDDs). It provides some background knowledge and describes the core algorithms. It is used in the course "C4340 Advanced Algorithms" at the Technical University of Denmark, autumn 1996.......This note is a short introduction to Binary Decision Diagrams (BDDs). It provides some background knowledge and describes the core algorithms. It is used in the course "C4340 Advanced Algorithms" at the Technical University of Denmark, autumn 1996....

Where are the Binaries? Results of a Long-term Search for Radial Velocity Binaries in Proto-planetary Nebulae

Energy Technology Data Exchange (ETDEWEB)

Hrivnak, Bruce J.; Lu, Wenxian [Department of Physics and Astronomy, Valparaiso University, Valparaiso, IN 46383 (United States); Steene, Griet Van de [Royal Observatory of Belgium, Astronomy and Astrophysics, Ringlaan 3, Brussels (Belgium); Winckel, Hans Van [Instituut voor Sterrenkunde, K.U. Leuven University, Celestijnenlaan 200 D, B-3001 Leuven (Belgium); Sperauskas, Julius [Vilnius University Observatory, Ciurlionio 29 Vilnius 2009 (Lithuania); Bohlender, David, E-mail: bruce.hrivnak@valpo.edu, E-mail: wen.lu@valpo.edu, E-mail: g.vandesteene@oma.be, E-mail: Hans.VanWinckel@ster.kuleuven.be, E-mail: julius.sperauskas@ff.vu.lt, E-mail: David.Bohlender@nrc-cnrc.gc.ca [National Research Council of Canada, Herzberg Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada)

2017-09-10

We present the results of an expanded, long-term radial velocity search (25 years) for evidence of binarity in a sample of seven bright proto-planetary nebulae (PPNe). The goal is to investigate the widely held view that the bipolar or point-symmetric shapes of planetary nebulae (PNe) and PPNe are due to binary interactions. Observations from three observatories were combined from 2007 to 2015 to search for variations on the order of a few years and then combined with earlier observations from 1991 to 1995 to search for variations on the order of decades. All seven show velocity variations due to periodic pulsation in the range of 35–135 days. However, in only one PPN, IRAS 22272+5435, did we find even marginal evidence for multi-year variations that might be due to a binary companion. This object shows marginally significant evidence of a two-year period of low semi-amplitude, which could be due to a low-mass companion, and it also displays some evidence of a much longer period of >30 years. The absence of evidence in the other six objects for long-period radial velocity variations due to a binary companion sets significant constraints on the properties of any undetected binary companions: they must be of low mass, ≤0.2 M {sub ⊙}, or long period, >30 years. Thus the present observations do not provide direct support for the binary hypothesis to explain the shapes of PNe and PPNe and severely constrains the properties of any such undetected companions.

Gravitational waves from spinning eccentric binaries

Science.gov (United States)

Csizmadia, Péter; Debreczeni, Gergely; Rácz, István; Vasúth, Mátyás

2012-12-01

This paper is to introduce a new software called CBwaves which provides a fast and accurate computational tool to determine the gravitational waveforms yielded by generic spinning binaries of neutron stars and/or black holes on eccentric orbits. This is done within the post-Newtonian (PN) framework by integrating the equations of motion and the spin precession equations, while the radiation field is determined by a simultaneous evaluation of the analytic waveforms. In applying CBwaves various physically interesting scenarios have been investigated. In particular, we have studied the appropriateness of the adiabatic approximation, and justified that the energy balance relation is indeed insensitive to the specific form of the applied radiation reaction term. By studying eccentric binary systems, it is demonstrated that circular template banks are very ineffective in identifying binaries even if they possess tiny residual orbital eccentricity, thus confirming a similar result obtained by Brown and Zimmerman (2010 Phys. Rev. D 81 024007). In addition, by investigating the validity of the energy balance relation we show that, contrary to the general expectations, the PN approximation should not be applied once the PN parameter gets beyond the critical value ˜0.08 - 0.1. Finally, by studying the early phase of the gravitational waves emitted by strongly eccentric binary systems—which could be formed e.g. in various many-body interactions in the galactic halo—we have found that they possess very specific characteristics which may be used to identify these type of binary systems. This paper is dedicated to the memory of our colleague and friend Péter Csizmadia a young physicist, computer expert and one of the best Hungarian mountaineers who disappeared in China’s Sichuan near the Ren Zhong Feng peak of the Himalayas on 23 Oct. 2009. We started to develop CBwaves jointly with Péter a couple of months before he left for China.

Rotation invariant deep binary hashing for fast image retrieval

Science.gov (United States)

Dai, Lai; Liu, Jianming; Jiang, Aiwen

2017-07-01

In this paper, we study how to compactly represent image's characteristics for fast image retrieval. We propose supervised rotation invariant compact discriminative binary descriptors through combining convolutional neural network with hashing. In the proposed network, binary codes are learned by employing a hidden layer for representing latent concepts that dominate on class labels. A loss function is proposed to minimize the difference between binary descriptors that describe reference image and the rotated one. Compared with some other supervised methods, the proposed network doesn't have to require pair-wised inputs for binary code learning. Experimental results show that our method is effective and achieves state-of-the-art results on the CIFAR-10 and MNIST datasets.

The Frequency of Binary Stars in the Globular Cluster M71

Science.gov (United States)

Barden, S. C.; Armandroff, T. E.; Pryor, C. P.

1994-12-01

The frequency of binary stars is a fundamental property of a stellar population. A comparison of the frequency of binaries in globular clusters with those in the field halo and disk populations tests the similarity of star formation in those environments. Binary stars in globular clusters also act as an energy source which ``heats" the cluster through super-elastic encounters with other stars and binaries. Such encounters can not only profoundly affect the dynamical evolution of the cluster, they can disrupt the widely separated binaries and catalyze the formation of exotic objects such as blue stragglers, x-ray binaries, and milli-second pulsars. We have used the KPNO 4-m and the multi-fiber instruments Nessie and Hydra to measure radial velocities at 4 epochs over two years for a sample of 126 stars in the globular cluster M71. Velocity errors are under 1 km s(-1) for the brighter stars and under 2 km s(-1) for the majority of our data set. These velocities will be valuable for studying the kinematics of M71, but here we focus on searching for binaries. The faintest stars are at V=17, or just above the main sequence turnoff. Our sample is thus deeper than any published globular cluster binary search utilizing spectroscopic techniques. By observing smaller stars, we double the number of decades of binary periods sampled compared to previous studies and come within a factor of 4 of the shortest possible periods for turnoff stars. This wider period window has produced the largest known sample of binaries in a globular cluster. Four stars show velocity ranges larger than 20 km s(-1) , nine have ranges larger than 10 km s(-1) , and others are clearly variable. We will compare the radial distribution of these stars to that predicted by theory and derive the main-sequence binary fraction.

Binary black holes on a budget: simulations using workstations

International Nuclear Information System (INIS)

Marronetti, Pedro; Tichy, Wolfgang; Bruegmann, Bernd; Gonzalez, Jose; Hannam, Mark; Husa, Sascha; Sperhake, Ulrich

2007-01-01

Binary black hole simulations have traditionally been computationally very expensive: current simulations are performed in supercomputers involving dozens if not hundreds of processors, thus systematic studies of the parameter space of binary black hole encounters still seem prohibitive with current technology. Here we show how the multi-layered refinement level code BAM can be used on dual processor workstations to simulate certain binary black hole systems. BAM, based on the moving punctures method, provides grid structures composed of boxes of increasing resolution near the centre of the grid. In the case of binaries, the highest resolution boxes are placed around each black hole and they track them in their orbits until the final merger when a single set of levels surrounds the black hole remnant. This is particularly useful when simulating spinning black holes since the gravitational fields gradients are larger. We present simulations of binaries with equal mass black holes with spins parallel to the binary axis and intrinsic magnitude of S/m 2 = 0.75. Our results compare favourably to those of previous simulations of this particular system. We show that the moving punctures method produces stable simulations at maximum spatial resolutions up to M/160 and for durations of up to the equivalent of 20 orbital periods

Compact Binary Progenitors of Short Gamma-Ray Bursts

Science.gov (United States)

Giacomazzo, Bruno; Perna, Rosalba; Rezzolla, Luciano; Troja, Eleonora; Lazzati, Davide

2013-01-01

In recent years, detailed observations and accurate numerical simulations have provided support to the idea that mergers of compact binaries containing either two neutron stars (NSs) or an NS and a black hole (BH) may constitute the central engine of short gamma-ray bursts (SGRBs). The merger of such compact binaries is expected to lead to the production of a spinning BH surrounded by an accreting torus. Several mechanisms can extract energy from this system and power the SGRBs. Here we connect observations and numerical simulations of compact binary mergers, and use the current sample of SGRBs with measured energies to constrain the mass of their powering tori. By comparing the masses of the tori with the results of fully general-relativistic simulations, we are able to infer the properties of the binary progenitors that yield SGRBs. By assuming a constant efficiency in converting torus mass into jet energy epsilon(sub jet) = 10%, we find that most of the tori have masses smaller than 0.01 Solar M, favoring "high-mass" binary NSs mergers, i.e., binaries with total masses approx >1.5 the maximum mass of an isolated NS. This has important consequences for the gravitational wave signals that may be detected in association with SGRBs, since "high-mass" systems do not form a long-lived hypermassive NS after the merger. While NS-BH systems cannot be excluded to be the engine of at least some of the SGRBs, the BH would need to have an initial spin of approx. 0.9 or higher.

Young and Waltzing Binary Stars

Science.gov (United States)

2001-10-01

ADONIS Observes Low-mass Eclipsing System in Orion Summary A series of very detailed images of a binary system of two young stars have been combined into a movie . In merely 3 days, the stars swing around each other. As seen from the earth, they pass in front of each other twice during a full revolution, producing eclipses during which their combined brightness diminishes . A careful analysis of the orbital motions has now made it possible to deduce the masses of the two dancing stars . Both turn out to be about as heavy as our Sun. But while the Sun is about 4500 million years old, these two stars are still in their infancy. They are located some 1500 light-years away in the Orion star-forming region and they probably formed just 10 million years ago . This is the first time such an accurate determination of the stellar masses could be achieved for a young binary system of low-mass stars . The new result provides an important piece of information for our current understanding of how young stars evolve. The observations were obtained by a team of astronomers from Italy and ESO [1] using the ADaptive Optics Near Infrared System (ADONIS) on the 3.6-m telescope at the ESO La Silla Observatory. PR Photo 29a/01 : The RXJ 0529.4+0041 system before primary eclipse PR Photo 29b/01 : The RXJ 0529.4+0041 system at mid-primary eclipse PR Photo 29c/01 : The RXJ 0529.4+0041 system after primary eclipse PR Photo 29d/01 : The RXJ 0529.4+0041 system before secondary eclipse PR Photo 29e/01 : The RXJ 0529.4+0041 system at mid-secondary eclipse PR Photo 29f/01 : The RXJ 0529.4+0041 system after secondary eclipse PR Video Clip 06/01 : Video of the RXJ 0529.4+0041 system Binary stars and stellar masses Since some time, astronomers have noted that most stars seem to form in binary or multiple systems. This is quite fortunate, as the study of binary stars is the only way in which it is possible to measure directly one of the most fundamental quantities of a star, its mass. The mass of a

Long-term captures of low-mass intruders by binary stars

International Nuclear Information System (INIS)

Hills, J.G.

1983-01-01

Intensive computer simulations were made of three families of encounters between a binary star and a low-mass intruder which previous work indicated have a high probability of producing long-lived triple-star systems. For comparison, a fourth family which produces few long-lived trinaries was also studied. In the first two families, the binary components are equally massive and the closest approach of the intruder to the center of mass of the binary is about two times its semimajor axis, a 0 . In Family 1, the orbit of the original binary is circular, e = 0, while in Family 2, e 0 = 0.95. In Family 3 one binary component is 100 times as massive as the other, the orbit is circular, and the low-mass intruder enters the binary at nearly zero impact parameter. The probability that the intruder is trapped for at least one revolution around the binary is 0.24, 0.46, and 0.51, respectively, for these three families of encounters. The fraction of the intruders surviving successive revolutions drops rapidly. However, one encounter in Family 1 and two in Family 3 resulted in the intruder making more than 300 revolutions around the inner binary before escaping. Some intruders remained bound for more than 20 000 revolutions of the inner binary. The longest duration captures occur when the intruder is thrown into an orbit with a very large semimajor axis. About 20% of the encounters in the three families result in the intruder being thrown into an orbit with a semimajor axis a>100 a 0 , while about 2% result in the intruder going into an orbit with a>1000 a 0 . Intruders thrown into these large semimajor axis orbits have the best chance of having their orbits stabilized by passing stars

THE BINARY FRACTION OF LOW-MASS WHITE DWARFS

International Nuclear Information System (INIS)

Brown, Justin M.; Kilic, Mukremin; Brown, Warren R.; Kenyon, Scott J.

2011-01-01

We describe spectroscopic observations of 21 low-mass (≤0.45 M sun ) white dwarfs (WDs) from the Palomar-Green survey obtained over four years. We use both radial velocities and infrared photometry to identify binary systems, and find that the fraction of single, low-mass WDs is ≤30%. We discuss the potential formation channels for these single stars including binary mergers of lower-mass objects. However, binary mergers are not likely to explain the observed number of single low-mass WDs. Thus, additional formation channels, such as enhanced mass loss due to winds or interactions with substellar companions, are likely.

Formation of the wide asynchronous binary asteroid population

International Nuclear Information System (INIS)

Jacobson, Seth A.; Scheeres, Daniel J.; McMahon, Jay

2014-01-01

We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semimajor axes relative to most near-Earth and main belt asteroid systems. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, from planetary flybys, and directly from rotational fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (1) these systems are formed from rotational fission, (2) their satellites are tidally locked, (3) their orbits are expanded by the binary Yarkovsky-O'Keefe-Radzievskii-Paddack (BYORP) effect, (4) their satellites desynchronize as a result of the adiabatic invariance between the libration of the secondary and the mutual orbit, and (5) the secondary avoids resynchronization because of the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torque that acts on the system. After detailing the theory, we analyze each of the wide asynchronous binary members and candidates to assess their most likely formation mechanism. Finally, we suggest possible future observations to check and constrain our hypothesis.

Construction of binary status information system using PC network

International Nuclear Information System (INIS)

Kurnianto, K.; Azriani, A.; Teddy, S.

1998-01-01

Binary status information system is a part of establishing reactor parameter with Pc that function as MPR-30 Process Computer. Binary Alarm system, consist of interface hardware and input binary module terminal, prepare the information that be displayed in text message and graphical form. Monitor software give facilities that binary status of RSG-GAS components can be monitored using computer network (LAN). This program consist of two part : reside in server computer and reside in user computer. Program in server acquire data from interface and than store it in data base (Access file). Than, user computer read this file and display it in Dynamic Process and Instrumentation Diagram. The number of user computer can be more then one because data base was designed for multi-user operation

Massive Black-Hole Binary Mergers: Dynamics, Environments & Expected Detections

Science.gov (United States)

Kelley, Luke Zoltan

2018-05-01

This thesis studies the populations and dynamics of massive black-hole binaries and their mergers, and explores the implications for electromagnetic and gravitational-wave signals that will be detected in the near future. Massive black-holes (MBH) reside in the centers of galaxies, and when galaxies merge, their MBH interact and often pair together. We base our study on the populations of MBH and galaxies from the `Illustris' cosmological hydrodynamic simulations. The bulk of the binary merger dynamics, however, are unresolved in cosmological simulations. We implement a suite of comprehensive physical models for the merger process, like dynamical friction and gravitational wave emission, which are added in post-processing. Contrary to many previous studies, we find that the most massive binaries with near equal-mass companions are the most efficient at coalescing; though the process still typically takes gigayears.From the data produced by these MBH binary populations and their dynamics, we calculate the expected gravitational wave (GW) signals: both the stochastic, GW background of countless unresolved sources, and the GW foreground of individually resolvable binaries which resound above the noise. Ongoing experiments, called pulsar timing arrays, are sensitive to both of these types of signals. We find that, while the current lack of detections is unsurprising, both the background and foreground will plausibly be detected in the next decade. Unlike previous studies which have predicted the foreground to be significantly harder to detect than the background, we find their typical amplitudes are comparable.With traditional electromagnetic observations, there has also been a dearth of confirmed detections of MBH binary systems. We use our binaries, combined with models of emission from accreting MBH systems, to make predictions for the occurrence rate of systems observable using photometric, periodic-variability surveys. These variables should be detectable in

Formation and Evolution of Contact Binaries

Directory of Open Access Journals (Sweden)

Peter P. Eggleton

2012-06-01

Full Text Available describe a series of processes, including hierarchical fragmentation, gravitational scattering, Kozai cycles within triple systems, tidal friction and magnetic braking, that I believe are responsible for producing the modest but significant fraction of stars that are observed as contact binaries. I also discuss further processes, namely heat transport, mass transport, nuclear evolution, thermal relaxation oscillations, and further magnetic braking with tidal friction, that influence the evolution during contact. The endpoint, for contact, is that the two components merge into a single star, as recently was observed in the remarkable system V1309 Sco. The single star probably throws off some mass and rotates rapidly at first, and then slows by magnetic braking to become a rather inconspicuous but normal dwarf or subgiant. If however the contact binary was part of a triple system originally–as I suggested above was rather likely–then the result could be a widish binary with apparently non-coeval components. There are several such known.

Compact binary hashing for music retrieval

Science.gov (United States)

Seo, Jin S.

2014-03-01

With the huge volume of music clips available for protection, browsing, and indexing, there is an increased attention to retrieve the information contents of the music archives. Music-similarity computation is an essential building block for browsing, retrieval, and indexing of digital music archives. In practice, as the number of songs available for searching and indexing is increased, so the storage cost in retrieval systems is becoming a serious problem. This paper deals with the storage problem by extending the supervector concept with the binary hashing. We utilize the similarity-preserving binary embedding in generating a hash code from the supervector of each music clip. Especially we compare the performance of the various binary hashing methods for music retrieval tasks on the widely-used genre dataset and the in-house singer dataset. Through the evaluation, we find an effective way of generating hash codes for music similarity estimation which improves the retrieval performance.

Receptive fields selection for binary feature description.

Science.gov (United States)

Fan, Bin; Kong, Qingqun; Trzcinski, Tomasz; Wang, Zhiheng; Pan, Chunhong; Fua, Pascal

2014-06-01

Feature description for local image patch is widely used in computer vision. While the conventional way to design local descriptor is based on expert experience and knowledge, learning-based methods for designing local descriptor become more and more popular because of their good performance and data-driven property. This paper proposes a novel data-driven method for designing binary feature descriptor, which we call receptive fields descriptor (RFD). Technically, RFD is constructed by thresholding responses of a set of receptive fields, which are selected from a large number of candidates according to their distinctiveness and correlations in a greedy way. Using two different kinds of receptive fields (namely rectangular pooling area and Gaussian pooling area) for selection, we obtain two binary descriptors RFDR and RFDG .accordingly. Image matching experiments on the well-known patch data set and Oxford data set demonstrate that RFD significantly outperforms the state-of-the-art binary descriptors, and is comparable with the best float-valued descriptors at a fraction of processing time. Finally, experiments on object recognition tasks confirm that both RFDR and RFDG successfully bridge the performance gap between binary descriptors and their floating-point competitors.

Planetary Formation and Dynamics in Binary Systems

Science.gov (United States)

Xie, J. W.

2013-01-01

As of today, over 500 exoplanets have been detected since the first exoplanet was discovered around a solar-like star in 1995. The planets in binaries could be common as stars are usually born in binary or multiple star systems. Although current observations show that the planet host rate in multiple star systems is around 17%, this fraction should be considered as a lower limit because of noticeable selection effects against binaries in planet searches. Most of the current known planet-bearing binary systems are S-types, meaning the companion star acts as a distant satellite, typically orbiting the inner star-planet system over 100 AU away. Nevertheless, there are four systems with a smaller separation of 20 AU, including the Gamma Cephei, GJ 86, HD 41004, and HD 196885. In addition to the planets in circumprimary (S-type) orbits discussed above, planets in circumbinary (P-type) orbits have been found in only two systems. In this thesis, we mainly study the planet formation in the S-type binary systems. In chapter 1, we first summarize current observational facts of exoplanets both in single-star and binary systems, then review the theoretical models of planet formation, with special attention to the application in binary systems. Perturbative effects from stellar companions render the planet formation process in binary systems even more complex than that in single-star systems. The perturbations from a binary companion can excite planetesimal orbits, and increase their mutual impact velocities to the values that might exceed their escape velocity or even the critical velocity for the onset of eroding collisions. The intermediate stage of the formation process---from planetesimals to planetary embryos---is thus the most problematic. In the following chapters, we investigate whether and how the planet formation goes through such a problematic stage. In chapter 2, we study the effects of gas dissipation on the planetesimals' mutual accretion. We find that in a

Binary classification posed as a quadratically constrained quadratic ...

Indian Academy of Sciences (India)

Binary classification is posed as a quadratically constrained quadratic problem and solved using the proposed method. Each class in the binary classification problem is modeled as a multidimensional ellipsoid to forma quadratic constraint in the problem. Particle swarms help in determining the optimal hyperplane or ...

The Cool Surfaces of Binaries Near-Earth Asteroids

NARCIS (Netherlands)

Delbo, Marco; Walsh, K.; Mueller, M.

2008-01-01

We present results from thermal-infrared observations of binary near-Earth asteroids (NEAs). These objects, in general, have surface temperatures cooler than the average values for non-binary NEAs. We discuss how this may be evidence of higher-than-average surface thermal inertia. The comparison of

The Mass-Ratio Distribution of Visual Binary Stars

NARCIS (Netherlands)

Hogeveen, S.J.

1990-01-01

The selection effects that govern the observations of Visual Binary Stars are in- vestigated, in order to obtain a realistic statistical distribution of the mass-ratio q = Msec=Mprim. To this end a numerical simulation programme has been developed, which `generates' binary stars and `looks' at

Evolution of close binaries and the formation of pulsars

International Nuclear Information System (INIS)

Van Den Heuvel, E.P.J.

1981-01-01

The various ways in which compact objects (neutron stars and black holes) may be formed in interacting binary systems are examined. Attention is given to the final evolution of the primary star in a close binary system as a function of the time of Roche-lobe overflow relative to the onset of helium burning, and conditions on primary mass and orbital period leading to the appearance of a compact remnant are noted. Consideration of the fate of the stellar envelope in stars that directly evolve to core collapse indicates that binaries that evolve with conservation of total mass and orbital angular momentum will eventually become systems of two runaway pulsars. In cases of nonconservative evolution, the final state is expected to be a young runaway pulsar with a low- or moderate mass runaway star companion, or a low-mass population I X-ray binary with high space velocity. Compact objects may also be formed when a white dwarf of suitable chemical composition is driven over the Chandrasehkar limit by accretion, resulting in a low-mass X-ray binary

Binary classification of items of interest in a repeatable process

Science.gov (United States)

Abell, Jeffrey A.; Spicer, John Patrick; Wincek, Michael Anthony; Wang, Hui; Chakraborty, Debejyo

2014-06-24

A system includes host and learning machines in electrical communication with sensors positioned with respect to an item of interest, e.g., a weld, and memory. The host executes instructions from memory to predict a binary quality status of the item. The learning machine receives signals from the sensor(s), identifies candidate features, and extracts features from the candidates that are more predictive of the binary quality status relative to other candidate features. The learning machine maps the extracted features to a dimensional space that includes most of the items from a passing binary class and excludes all or most of the items from a failing binary class. The host also compares the received signals for a subsequent item of interest to the dimensional space to thereby predict, in real time, the binary quality status of the subsequent item of interest.

Minimum period and the gap in periods of Cataclysmic binaries

International Nuclear Information System (INIS)

Paczynski, B.; Sienkiewicz, R.

1983-01-01

The 81 minute cutoff to the orbital periods of hydrogen-rich cataclysmic binaries is consistent with evolution of those systems being dominated by angular momentum losses due to gravitational radiation. Unfortunately, many uncertainties, mainly poorly known atmospheric opacities below 2000 K, make is physically impossible to verify the quadrupole formula for gravitational radiation by using the observed cutoff at 81 minutes. The upper boundary of the gap in orbital periods observed at about 3 hours is almost certainly due to enhanced angular momentum losses from cataclysmic binaries which have longer periods. The physical mechanism of those losses is not identified, but a possible importance of stellar winds is pointed out. The lower boundary of the gap may be explained with the oldest cataclysmic binaries, whose periods evolved past the minimum at 81 minutes and reached the value of 2 hours within about 12 x 10 9 years after the binary had formed. Those binaries should have secondary components of only 0.02 solar masses, and their periods could be used to estimate ages of the oldest cataclysmic stars, and presumably the age of Galaxy. An alternative explanation for the gap requires that binaries should be detached while crossing the gap. A possible mechanism for this phenomenon is discussed. It requires the secondary components to be about 0.2 solar masses in the binaries just below the gap

The Search for Binaries in Post-Asymptotic Giant Branch Stars: Do Binary Companions Shape the Nebulae?

Directory of Open Access Journals (Sweden)

Bruce J. Hrivnak

2012-03-01

Full Text Available Binary companions are often invoked to explain the axial and point symmetry seen in the majority of planetary nebulae and proto-planetary nebulae (PPNs. To explore this hypothesis, we have undertaken a long-term (20 year study of light and velocity variations in PPNs. From the photometric study of 24 PPNs, we find that all vary in brightness, and from a subset of 12 carbon-rich PPNs of F-G spectral type we find periods of 35-155 days, with the cooler having the longer periods. The variations are seen to be due to pulsation; no photometric evidence for binarity is seen. A radial velocity study of a sub-sample of seven of the brightest of these shows that they all vary with the pulsation periods. Only one shows evidence of a longer-term variation that we tentatively identify as being due to a binary companion. We conclude that the present evidence for the binary nature of these PPNs is meager and that any undetected companions of these PPNs must be of low mass ( 30 years.

Binary analysis: 1. part: definitions and treatment of binary functions; 2. part: applications and functions of trans-coding

International Nuclear Information System (INIS)

Vallee, R.L.

1968-01-01

The study of binary groups under their mathematical aspects constitutes the matter of binary analysis, the purpose of which consists in developing altogether simple, rigorous and practical methods needed by the technicians, the engineers and all those who may be mainly concerned by digital processing. This subject, fast extending if not determining, however tends actually to play a main part in nuclear electronics as well as in several other research areas. (authors) [fr

Excess molar volumes and isentropic compressibilities of binary

Indian Academy of Sciences (India)

Excess molar volumes (E) and deviation in isentropic compressibilities (s) have been investigated from the density and speed of sound measurements of six binary liquid mixtures containing -alkanes over the entire range of composition at 298.15 K. Excess molar volume exhibits inversion in sign in one binary ...

Misaligned disks in the binary protostar IRS 43

DEFF Research Database (Denmark)

Brinch, Christian; Jørgensen, Jes Kristian; Hogerheijde, Michiel R.

2016-01-01

and position angle and also with respect to the binary orbital plane. Each stellar component has an associated circumstellar disk while the binary is surrounded by a circumbinary disk. Together with archival VLA measurements of the stellar positions over 25 years, and assuming a circular orbit, we use our...

IUE observations of the eclipsing binary Epsilon Aurigae

International Nuclear Information System (INIS)

Hack, M.; Selvelli, P.L.

1978-01-01

It is stated that the eclipsing binary Epsilon Aur is a most peculiar binary system and it has not been explained satisfactorily. Observations of this system using the International Ultraviolet Explorer (IUE) collected at the Villafranca Satellite Tracking Station of the European Space Agency are here reported. (author)

Binary spectral minutiae representation with multi-sample fusion for fingerprint recognition

NARCIS (Netherlands)

Xu, H.; Veldhuis, Raymond N.J.

Biometric fusion is the approach to improve the biometric system performance by combining multiple sources of biometric information. The binary spectral minutiae representation is a method to represent a fingerprint minutiae set as a fixed-length binary string. This binary representation has the

Activity in X-ray-selected late-type stars

International Nuclear Information System (INIS)

Takalo, L.O.; Nousek, J.A.

1988-01-01

A spectroscopic study has been conducted of nine X-ray bright late-type stars selected from two Einstein X-ray surveys: the Columbia Astrophysical Laboratory Survey (five stars) and the CFA Medium Sensitivity Survey (MSS; four stars). Spectral classes were determined and radial and V sin(i) velocities were measured for the stars. Four of the Columbia Survey stars were found to be new RS CVn-type binaries. The fifth Columbia survey star was found to be an active G dwarf star without evidence for binarity. None of the four MSS stars were found to be either binaries or optically active stars. Activity in these stars was assessed by measuring the excess emission in H-alpha and the Ca II IRT (8498, 8542) lines in comparison with inactive stars of similar spectral types. A correlation was found between X-ray luminosity and V sin(i) and H-alpha line excess. The measured excess line emission in H-alpha was also correlated with V sin(i) but not with the IRT line excess. 36 references

A Search for Exoplanets in Short-Period Binary Star Systems

Directory of Open Access Journals (Sweden)

Ronald Kaitchuck

2012-03-01

Full Text Available This paper reports the progress of a search for exoplanets with S-type orbits in short-period binary star systems. The selected targets have stellar orbital periods of just a few days. These systems are eclipsing binaries so that exoplanet transits, if planets exist, will be highly likely. We report the results for seven binary star systems.

KIC 7177553: A QUADRUPLE SYSTEM OF TWO CLOSE BINARIES

Energy Technology Data Exchange (ETDEWEB)

Lehmann, H. [Thüringer Landessternwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg (Germany); Borkovits, T. [Baja Astronomical Observatory of Szeged University, H-6500 Baja, Szegedi út, Kt. 766 (Hungary); Rappaport, S. A. [Massachusetts Institute of Technology, Department of Physics, 77 Massachusetts Avenue, Cambridge, MA 02139-4307 (United States); Ngo, H. [California Institute of Technology, Division of Geological and Planetary Sciences, 1200 E. California Boulevard, MC 150-21, Pasadena, CA 91125 (United States); Mawet, D. [California Institute of Technology, Astronomy Dept. MC 249-17, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Csizmadia, Sz. [German Aerospace Center (DLR), Institut für Planeten-forschung, Rutherfordstraße 2, D-12489 Berlin (Germany); Forgács-Dajka, E., E-mail: lehm@tls-tautenburg.de, E-mail: borko@electra.bajaobs.hu, E-mail: sar@mit.edu, E-mail: hngo@caltech.edu, E-mail: dmawet@astro.caltech.edu, E-mail: szilard.csizmadia@dlr.de, E-mail: e.forgacs-dajka@astro.elte.hu [Astronomical Department, Eötvös University, H-1118 Budapest, Pázmány Péter stny. 1/A (Hungary)

2016-03-01

KIC 7177553 was observed by the Kepler satellite to be an eclipsing eccentric binary star system with an 18-day orbital period. Recently, an eclipse timing study of the Kepler binaries has revealed eclipse timing variations (ETVs) in this object with an amplitude of ∼100 s and an outer period of 529 days. The implied mass of the third body is that of a super-Jupiter, but below the mass of a brown dwarf. We therefore embarked on a radial velocity (RV) study of this binary to determine its system configuration and to check the hypothesis that it hosts a giant planet. From the RV measurements, it became immediately obvious that the same Kepler target contains another eccentric binary, this one with a 16.5-day orbital period. Direct imaging using adaptive optics reveals that the two binaries are separated by 0.″4 (∼167 AU) and have nearly the same magnitude (to within 2%). The close angular proximity of the two binaries and very similar γ velocities strongly suggest that KIC 7177553 is one of the rare SB4 systems consisting of two eccentric binaries where at least one system is eclipsing. Both systems consist of slowly rotating, nonevolved, solar-like stars of comparable masses. From the orbital separation and the small difference in γ velocity, we infer that the period of the outer orbit most likely lies in the range of 1000–3000 yr. New images taken over the next few years, as well as the high-precision astrometry of the Gaia satellite mission, will allow us to set much narrower constraints on the system geometry. Finally, we note that the observed ETVs in the Kepler data cannot be produced by the second binary. Further spectroscopic observations on a longer timescale will be required to prove the existence of the massive planet.

Binaries discovered by the SPY project V. GD 687 - a massive double degenerate binary progenitor that will merge within a Hubble time

OpenAIRE

Geier, S.; Heber, U.; Kupfer, T.; Napiwotzki, R.

2010-01-01

Aims. The ESO SN Ia Progenitor Survey (SPY) aims at finding merging double degenerate binaries as candidates for supernova type Ia (SN Ia) explosions. A white dwarf merger has also been suggested to explain the formation of rare types of stars like R CrB, extreme helium or He sdO stars. Here we present the hot subdwarf B binary GD 687, which will merge in less than a Hubble time. Methods. The orbital parameters of the close binary have been determined from time resolved spectroscopy. Since GD...

Characterization of the startup transient electrokinetic flow in rectangular channels of arbitrary dimensions, zeta potential distribution, and time-varying pressure gradient.

Science.gov (United States)

Miller, Andrew; Villegas, Arturo; Diez, F Javier

2015-03-01

The solution to the startup transient EOF in an arbitrary rectangular microchannel is derived analytically and validated experimentally. This full 2D transient solution describes the evolution of the flow through five distinct periods until reaching a final steady state. The derived analytical velocity solution is validated experimentally for different channel sizes and aspect ratios under time-varying pressure gradients. The experiments used a time resolved micro particle image velocimetry technique to calculate the startup transient velocity profiles. The measurements captured the effect of time-varying pressure gradient fields derived in the analytical solutions. This is tested by using small reservoirs at both ends of the channel which allowed a time-varying pressure gradient to develop with a time scale on the order of the transient EOF. Results showed that under these common conditions, the effect of the pressure build up in the reservoirs on the temporal development of the transient startup EOF in the channels cannot be neglected. The measurements also captured the analytical predictions for channel walls made of different materials (i.e., zeta potentials). This was tested in channels that had three PDMS and one quartz wall, resulting in a flow with an asymmetric velocity profile due to variations in the zeta potential between the walls. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Control of broadband optically generated ultrasound pulses using binary amplitude holograms.

Science.gov (United States)

Brown, Michael D; Jaros, Jiri; Cox, Ben T; Treeby, Bradley E

2016-04-01

In this work, the use of binary amplitude holography is investigated as a mechanism to focus broadband acoustic pulses generated by high peak-power pulsed lasers. Two algorithms are described for the calculation of the binary holograms; one using ray-tracing, and one using an optimization based on direct binary search. It is shown using numerical simulations that when a binary amplitude hologram is excited by a train of laser pulses at its design frequency, the acoustic field can be focused at a pre-determined distribution of points, including single and multiple focal points, and line and square foci. The numerical results are validated by acoustic field measurements from binary amplitude holograms, excited by a high peak-power laser.

Binary black hole in a double magnetic monopole field

Science.gov (United States)

Rodriguez, Maria J.

2018-01-01

Ambient magnetic fields are thought to play a critical role in black hole jet formation. Furthermore, dual electromagnetic signals could be produced during the inspiral and merger of binary black hole systems. In this paper, we derive the exact solution for the electromagnetic field occurring when a static, axisymmetric binary black hole system is placed in the field of two magnetic or electric monopoles. As a by-product of this derivation, we also find the exact solution of the binary black hole configuration in a magnetic or electric dipole field. The presence of conical singularities in the static black hole binaries represent the gravitational attraction between the black holes that also drag the external two monopole field. We show that these off-balance configurations generate no energy outflows.

Binary black hole in a double magnetic monopole field

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, Maria J. [Utah State University, Department of Physics, Logan, UT (United States); Max Planck Institute for Gravitational Physics, Potsdam (Germany)

2018-01-15

Ambient magnetic fields are thought to play a critical role in black hole jet formation. Furthermore, dual electromagnetic signals could be produced during the inspiral and merger of binary black hole systems. In this paper, we derive the exact solution for the electromagnetic field occurring when a static, axisymmetric binary black hole system is placed in the field of two magnetic or electric monopoles. As a by-product of this derivation, we also find the exact solution of the binary black hole configuration in a magnetic or electric dipole field. The presence of conical singularities in the static black hole binaries represent the gravitational attraction between the black holes that also drag the external two monopole field. We show that these off-balance configurations generate no energy outflows. (orig.)

Population of Nuclei Via 7Li-Induced Binary Reactions

International Nuclear Information System (INIS)

Clark, Rodney M.; Phair, Larry W.; Descovich, M.; Cromaz, Mario; Deleplanque, M.A.; Fall on, Paul; Lee, I-Yang; Macchiavelli, A.O.; McMahan, Margaret A.; Moretto, Luciano G.; Rodriguez-Vieitez, E.; Sinha, Shrabani; Stephens, Frank S.; Ward, David; Wiedeking, Mathis

2005-01-01

The authors have investigated the population of nuclei formed in binary reactions involving 7 Li beams on targets of 160 Gd and 184 W. The 7 Li + 184 W data were taken in the first experiment using the LIBERACE Ge-array in combination with the STARS Si ΔE-E telescope system at the 88-Inch Cyclotron of the Lawrence Berkeley National Laboratory. By using the Wilczynski binary transfer model, in combination with a standard evaporation model, they are able to reproduce the experimental results. This is a useful method for predicting the population of neutron-rich heavy nuclei formed in binary reactions involving beams of weakly bound nuclei formed in binary reactions involving beams of weakly bound nuclei and will be of use in future spectroscopic studies

Numerical Simulations of Wind Accretion in Symbiotic Binaries

Science.gov (United States)