Close binary stars in the solar-age Galactic open cluster M67

We present multi-colour time-series CCD photometry of the solar-age galactic open cluster M67 (NGC 2682). About 3600 frames spread over 28 nights were obtained with the 1.5 m Russian-Turkish and 1.2 m Mercator telescopes. High-precision observations of the close binary stars AH Cnc, EV Cnc, ES Cnc, the $\delta$ Scuti type systems EX Cnc and EW Cnc, and some long-period variables belonging to M67 are presented. Three full multi-colour light curves of the overcontact binary AH Cnc were obtained during three observing seasons. Likewise we gathered three light curves of EV Cnc, an EB-type binary, and two light curves of ES Cnc, a blue straggler binary. Parts of the light change of long-term variables S1024, S1040, S1045, S1063, S1242, and S1264 are obtained. Period variation analysis of AH Cnc, EV Cnc, and ES Cnc were done using all times of mid-eclipse available in the literature and those obtained in this study. In addition, we analyzed multi-colour light curves of the close binaries and also determined new frequencies for the $\delta$ Scuti systems. The physical parameters of the close binary stars were determined with simultaneous solutions of multi-colour light and radial velocity curves. Finally we determined the distance of M67 as 857(33) pc via binary star parameters, which is consistent with an independent method from earlier studies.Comment: 12 pages, 9 Figures, 13 Table

Study of damage control systems for space station

Damage control systems for detecting and locating overboard and onboard leak and damage modes on space station

Population Synthesis of Common Envelope Mergers: I. Giant Stars with Stellar or Substellar Companions

Using a population synthesis technique, we have calculated detailed models of the present-day field population of objects that have resulted from the merger of a giant primary and a main-sequence or brown dwarf secondary during common-envelope evolution. We used a grid of 116 stellar and 32 low-mass/brown dwarf models, a crude model of the merger process, and followed the angular momentum evolution of the binary orbit and the primary's rotation prior to merger, as well as the merged object's rotation after the merger. We find that present-day merged objects that are observable as giant stars or core-helium burning stars in our model population constitute between 0.24% and 0.33% of the initial population of ZAMS binaries, depending upon the input parameters chosen. The median projected rotational velocity of these merged objects is ~16 km/sec, an order of magnitude higher than the median projected rotational velocity in a model population of normal single stars calculated using the same stellar models and initial mass function. The masses of the merged objects are typically less than ~2 solar masses, with a median mass of 1.28 solar masses, which is slightly more than, but not significantly different from, their normal single star counterparts. The luminosities in our merged object population range from ~10-100 solar luminosities, with a strong peak in the luminosity distribution at ~60 solar luminosities, since the majority of the merged objects (57%) lie on the horizontal branch at the present epoch. The results of our population synthesis study are discussed in terms of possible observational counterparts either directly involving the high rotational velocity of the merger product or indirectly, via the effect of rotation on envelope abundances and on the amount and distribution of circumstellar matter.Comment: 16 pages, 12 figures, accepted for publication in the Astrophysical Journa

Absolute properties of the binary system BB Pegasi

We present a ground based photometry of the low-temperature contact binary BB Peg. We collected all times of mid-eclipses available in literature and combined them with those obtained in this study. Analyses of the data indicate a period increase of 3.0(1) x 10^{-8} days/yr. This period increase of BB Peg can be interpreted in terms of the mass transfer 2.4 x 10^{-8} Ms yr^{-1} from the less massive to the more massive component. The physical parameters have been determined as Mc = 1.42 Ms, Mh = 0.53 Ms, Rc = 1.29 Rs, Rh = 0.83 Rs, Lc = 1.86 Ls, and Lh = 0.94 Ls through simultaneous solution of light and of the radial velocity curves. The orbital parameters of the third body, that orbits the contact system in an eccentric orbit, were obtained from the period variation analysis. The system is compared to the similar binaries in the Hertzsprung-Russell and Mass-Radius diagram.Comment: 17 pages, 3 figures, accepted for Astronomical Journa

EUROCODES: BACKGROUND & APPLICATIONS: Elaboration of maps for climatic and seismic actions for structural design with the Eurocodes

Activities for promotion of policies for sustainable construction in the Balkan region Guidance for countries adopting the Eurocodes State-of-the-art material to elaborate maps for seismic and climatic actions for structural design Experience of the non-EU Balkan countries on elaboration of these mapsJRC.E.4 - Safety and Security of Building

Towards ensemble asteroseismology of the young open clusters Chi Persei and NGC 6910

As a result of the variability survey in Chi Persei and NGC6910, the number of Beta Cep stars that are members of these two open clusters is increased to twenty stars, nine in NGC6910 and eleven in Chi Persei. We compare pulsational properties, in particular the frequency spectra, of Beta Cep stars in both clusters and explain the differences in terms of the global parameters of the clusters. We also indicate that the more complicated pattern of the variability among B type stars in Chi Persei is very likely caused by higher rotational velocities of stars in this cluster. We conclude that the sample of pulsating stars in the two open clusters constitutes a very good starting point for the ensemble asteroseismology of Beta Cep-type stars and maybe also for other B-type pulsators.Comment: 4 pages, Astronomische Nachrichten, HELAS IV Conference, Arecife, Lanzarote, Feb 2010, submitte

Accurate masses and radii of normal stars: modern results and applications

This paper presents and discusses a critical compilation of accurate, fundamental determinations of stellar masses and radii. We have identified 95 detached binary systems containing 190 stars (94 eclipsing systems, and alpha Centauri) that satisfy our criterion that the mass and radius of both stars be known to 3% or better. To these we add interstellar reddening, effective temperature, metal abundance, rotational velocity and apsidal motion determinations when available, and we compute a number of other physical parameters, notably luminosity and distance. We discuss the use of this information for testing models of stellar evolution. The amount and quality of the data also allow us to analyse the tidal evolution of the systems in considerable depth, testing prescriptions of rotational synchronisation and orbital circularisation in greater detail than possible before. The new data also enable us to derive empirical calibrations of M and R for single (post-) main-sequence stars above 0.6 M(Sun). Simple, polynomial functions of T(eff), log g and [Fe/H] yield M and R with errors of 6% and 3%, respectively. Excellent agreement is found with independent determinations for host stars of transiting extrasolar planets, and good agreement with determinations of M and R from stellar models as constrained by trigonometric parallaxes and spectroscopic values of T(eff) and [Fe/H]. Finally, we list a set of 23 interferometric binaries with masses known to better than 3%, but without fundamental radius determinations (except alpha Aur). We discuss the prospects for improving these and other stellar parameters in the near future.Comment: 56 pages including figures and tables. To appear in The Astronomy and Astrophysics Review. Ascii versions of the tables will appear in the online version of the articl

Improving vocabulary outcomes in inclusive secondary science classrooms through professional development

Secondary students with learning disabilities are likely to learn science in an inclusive classroom. Their success often depends on teachers’ ability to support their literacy needs. In this quasiexperimental study, we examine the effect of teacher’ involvement in intensive professional development designed to deepen secondary science teachers’ knowledge of evidence-based morphological awareness practices and implementation of evidence-based morphological awareness instruction, and to improve students’ science vocabulary knowledge. Teachers (n = 6) increased their knowledge of evidence-based morphological awareness practices and use of evidence-based morphological awareness instruction. Furthermore, their students’ (n = 55) knowledge of science vocabulary improved. We provide recommendations for future research, and discuss implications for the way districts and teacher educators design professional development and for improving the accessibility of science content

A fuzzy based model proposal on risk analysis for human-robot interactive systems

4th International Congress on Human-Computer Interaction, Optimization and Robotic Applications, HORA 2022 -- 9 June 2022 through 11 June 2022 -- -- 180434The role and job descriptions of the new generation of industrial robots that will operate in smart factories are being shaped by the industry 4.0 (I4.0) process, which has evolved with digital transformation and advanced production procedures. Human-robot interaction is a new industry trend and a key component of the I4.0 strategy. The main objective of this new solution is to improve the safety, ergonomics, productivity, and quality of the process. This solution aims to bridge the gap between manual production and fully automated production. In this way, the employee integrates the advantage of both humans and robots by sharing the workspace with the robot in non-ergonomic, repetitive, uncomfortable, and dangerous operations. This also means that the inclusion of robots in manufacturing processes does not devalue the human component; on the contrary, it shows that the increase in productivity is due to human-robot cooperation. As the level of human-robot cooperation increases, production capacity must be waived as a result of the slowdown of robots by nature, and risk assessment becomes more important according to certain standards. It is also clear that risk analysis of human and robot interaction systems contains a mixture of quantitative and qualitative data based on human evaluations and hesitancy and process uncertainties. In general, risk assessment approaches rely on the expertise and experience of specialists. So, the fuzzy set theory (FST) is more suitable to evaluate the risk assessment of this system. This study aims to contribute to improving human-robot collaboration and safety in an industrial setting for risk assessment based on FST. Additionally, the z-number, which is a fuzzy number of pairs is integrated into the proposed methodology to reflect the uncertainties of the risk assessment stage. Within the scope of the study, a new fuzzy-based risk assessment methodology is proposed to provide a safe workplace where humans and robots collaborate on a typical task. The proposed methodology consists of DELPHI, DEMATEL, ANP, and VIKOR which are multi-criteria decisions making (MCDM) methods based on the z-numbers that can take into account the uncertainty of the data and the hesitancies of the experts. © 2022 IEEE