283 research outputs found

    Parametric study of manned life support systems. Volume 2 - Parametric relations and scaling law Final report, Jul. 1967- Aug. 1968

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    Parametric relations and scaling laws to describe manned life support system

    Analysis of MERCATOR data Part I: variable B stars

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    We re-classified 31 variable B stars which were observed more than 50 times in the Geneva photometric system with the P7 photometer attached to the MERCATOR telescope (La Palma) during its first 3 years of scientific observations. HD89688 is a possible beta Cephei/slowly pulsating B star hybrid and the main mode of the COROT target HD180642 shows non-linear effects. The Maia candidates are re-classified as either ellipsoidal variables or spotted stars. Although the mode identification is still ongoing, all the well-identified modes so far have a degree l = 0, 1 or 2.Comment: 4 pages, 3 figures. To appear in: Proceedings of JENAM 2005 'Distant worlds', Communications in Asteroseismolog

    Effect of the Premature Infant Oral Motor Intervention on Sucking Capacity in Preterm Infants in Turkey: A Randomized Controlled Trial

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    Background: Preterm infants have oral feeding difficulty that often delays discharge, indicating a need for evidence-based interventions for oral-motor development. Purpose: To test the Premature Infant Oral Motor Intervention (PIOMI) on the development of oral-motor function, feeding, and anthropometric outcomes using sucking manometry. Methods: A single-blind randomized experimental design was conducted with a sample of 60 preterm infants from 2 neonatal intensive care units between May 2019 and March 2020. The experimental group received PIOMI for 5 min/d for 14 consecutive days. Sucking capacity, anthropometrics (weight and head circumference), bottle feeding, breast/chest feeding initiation, and length of hospital stay were measured. The Yakut Sucking Manometer (PCT/TR2019/050678) was developed specifically for this study and tested for the first time. Results: The experimental group had a statistically significant percent increase over controls in sucking power (69%), continuous sucking before releasing the bottle (16%), sucking time (13%), and sucking amount (12%) with partial η2values of interaction between the groups of 0.692, 0.164, 0.136, and 0.121, respectively. The experimental group had a higher increase in weight (89%) and head circumference (81%) over controls (F = 485.130, P <.001; F = 254.754, P <.001, respectively). The experimental group transitioned to oral feeding 9.9 days earlier than controls (t = -2.822; P =.007), started breast/chest feeding 10.8 days earlier (t = 3.016; P =.004), and were discharged 3.0 days earlier. Implications for Research/Practice: The PIOMI had a significant positive effect on anthropometrics, sucking capacity, readiness to initiate bottle and breast/chest feeding, and a 3-day reduction in length of hospital stay. © 2022 Lippincott Williams and Wilkins. All rights reserved

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

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    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 δ\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 δ\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

    Dynamical evolution of active detached binaries on log Jo - log M diagram and contact binary formation

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    Orbital angular momentum (Jo), systemic mass (M) and orbital period (P) distributions of chromospherically active binaries (CAB) and W Ursae Majoris (W UMa) systems were investigated. The diagrams of log Jo - log P, log M - log P and log Jo-log M were formed from 119 CAB and 102 W UMa stars. The log Jo-log M diagram is found to be most meaningful in demonstrating dynamical evolution of binary star orbits. A slightly curved borderline (contact border) separating the detached and the contact systems was discovered on the log Jo - log M diagram. Since orbital size (a) and period (P) of binaries are determined by their current Jo, M and mass ratio q, the rates of orbital angular momentum loss (dlog Jo/dt) and mass loss (dlog M/dt) are primary parameters to determine the direction and the speed of the dynamical evolution. A detached system becomes a contact system if its own dynamical evolution enables it to pass the contact border on the log Jo - log M diagram. Evolution of q for a mass loosing detached system is unknown unless mass loss rate for each component is known. Assuming q is constant in the first approximation and using the mean decreasing rates of Jo and M from the kinematical ages of CAB stars, it has been predicted that 11, 23 and 39 cent of current CAB stars would transform to W UMa systems if their nuclear evolution permits them to live 2, 4 and 6 Gyrs respectively.Comment: 28 pages, including 6 figures and 2 tables, accepted for publication in MNRA

    Absolute properties of the binary system BB Pegasi

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    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

    Effect of heat treatment on the wear and corrosion behaviors of a gray cast iron coated with a COLMONOY 88 alloy deposited by high velocity oxygen fuel (HVOF) thermal spray

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    The present work has been conducted in order to determine the influence of heat treatment on the wear and corrosion behaviours of a gray cast iron substrate coated with a Ni base coating deposited by HVOF thermal spray. The wear resistance of the coatings was obtained using a reciprocating wear tester by rubbing a 10 mm diameter steel ball on the coatings at normal atmospheric conditions. Corrosion tests were performed using potentiodynamic polarization measurements in a 3,5 % NaCl solution. It was observed that the corrosion and wear resistance of the coatings increased along with the reduction of porosity and roughness by the heat treatment
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