Download or read book The Atmospheric Parameters of Main Sequence A and F Stars written by Barry Smalley and published by . This book was released on 1992 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Detailed Study of Giants and Horizontal Branch Stars in M68 written by Marc-Andre Schaeuble and published by . This book was released on 2015 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, I present a detailed high-resolution spectroscopic study of post main sequence stars in the Globular Cluster M68. My sample, which covers a range of 4000 K in Teff, and 3.5 dex in log(g), is comprised of members from the red giant, red horizontal, and blue horizontal branch, making this the first high-resolution globular cluster study covering such a large evolutionary and parameter space. Initially, atmospheric parameters were determined using photometric as well as spectroscopic methods, both of which resulted in unphysical and unexpected Teff, log(g), vt, and [Fe/H] combinations. I therefore developed a hybrid approach that addresses most of these problems, and yields atmospheric parameters that agree well with other measurements in the literature. Furthermore, my derived stellar metallicities are consistent across all evolutionary stages, with [Fe/H] = 2.42 ( sigma = 0.14) from 25 stars. Chemical abundances obtained using my methodology also agree with previous studies and bear all the hallmarks of globular clusters, such as a Na-O anti-correlation, constant Ca abundances, and mild r-process enrichment.
Download or read book Fundamental Atmospheric Parameters of B Stars in the Alpha Persei Open Cluster written by Rana Ezzeddine and published by . This book was released on 2012 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ages and Abundances of Local Galactic Stellar Populations written by Diane K. Feuillet and published by . This book was released on 2016 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chemical compositions of stellar atmospheres reflect the interstellar gas from which they formed, each one containing a snapshot of the Milky Way Galaxy’s chemical evolution. By comparing abundances of stars across the disk of our Galaxy, we can explore how different parts of the Galaxy were enriched, where star formation proceeded most rapidly, and whether there has been significant mixing of stars and gas through the disk. In general, older stars formed from material that had fewer metals and younger stars formed after more metals had been deposited into the interstellar medium. However, the relative dating of stars based on metallicity cannot easily be mapped to an absolute age, and the local age-metallicity relation cannot be used in different Galactic locations. The rate of metal enrichment depends strongly on the star formation rate. To use the full power of studying stellar atmosphere compositions across the Galaxy, we also need to determine absolute stellar ages. In this dissertation, I examine the ages and chemical abundances of stars in the solar neighborhood with the goal of extending this analysis to the larger APOGEE sample, which spans the full Milky Way disk. Through an independent analysis of optical spectra of APOGEE stars, I validate the individual chemical abundances measured by the near-infrared spectroscopic survey. The main stellar targets of APOGEE are red giant stars, for which the atmospheric parameters are degenerate with age. I develop a method of constraining the age distribution of a sample of giants, and determining individual ages to 0.1 dex, using a sample of local red giant stars with well measured distance. For the solar neighborhood, I find that the mean age of the sample is closely correlated with the abundance of [alpha]-elements in the stars, even at young ages. Using a sample of local subgiant stars, for which ages can be more precisely measured, I confirm this result for the solar neighborhood. I conclude that the method presented here for finding ages of red giant stars with known distances can robustly be applied to the full APOGEE sample for which distances will soon be available from the Gaia mission.
Download or read book Fundamentals of Rocket Propulsion written by DP Mishra and published by CRC Press. This book was released on 2017-07-20 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book follows a unified approach to present the basic principles of rocket propulsion in concise and lucid form. This textbook comprises of ten chapters ranging from brief introduction and elements of rocket propulsion, aerothermodynamics to solid, liquid and hybrid propellant rocket engines with chapter on electrical propulsion. Worked out examples are also provided at the end of chapter for understanding uncertainty analysis. This book is designed and developed as an introductory text on the fundamental aspects of rocket propulsion for both undergraduate and graduate students. It is also aimed towards practicing engineers in the field of space engineering. This comprehensive guide also provides adequate problems for audience to understand intricate aspects of rocket propulsion enabling them to design and develop rocket engines for peaceful purposes.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1969 with total page 1572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectral Classification and Multicolour Photometry written by CH. Fehrenbach and published by Springer Science & Business Media. This book was released on 2013-11-21 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dr J. Landi Dessy, Director of the Astronomical Observatory, Cordoba, Argentina, invited the International Astronomical Union to hold a Symposium in Cordoba in connection with the celebration of the Centennial of the Cordoba Observatory; the date of foundation is October 24, 1871. He proposed that the Symposium should deal with Spectral Classification and Multicolour Photometry as seven years had elapsed since the Symposium No. 24 in Saltsj6baden, and much development had occurred in the field. The invitation and the proposal were accepted by the IAU, and the Symposium was held in Villa Carlos Paz, near Cordoba, between October 18 and October 24, 1971. It was attended by about 50 scientists representing Argentina, Canada, Chile, Den mark, France, Germany, Italy, Mexico, Sweden, Switzerland, U.K., U.S.A., Vatican City State and Venezuela. The Symposium was divided into four sessions: 1. Classification of slit spectra, 2. Classification of objective-prism spectra, 3. Photometric classification, 4. Catalogues and documentation. It was decided not to include problems of calibration of absolute magnitudes and temperatures of stars but to refer this to a separate symposium. The contents of the present volume follow closely the programmes of the individual sessions of the Symposium. All the participants at the Symposium appreciated the excellent hospitality of their Argentinian hosts and the efficient help given by the staff ofthe Cordoba Observatory.
Download or read book Revista Mexicana de Astronom a Y Astrof sica written by and published by . This book was released on 2011 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rules of Thumb for Mechanical Engineers written by J. Edward Pope and published by Gulf Professional Publishing. This book was released on 1997 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluids -- Heat transfer -- Thermodynamics -- Mechanical seals -- Pumps and compressors -- Drivers -- Gears -- Bearings -- Piping and pressure vessels -- Tribology -- Vibration -- Materials -- Stress and strain -- Fatigue -- Instrumentation -- Engineering economics.
Download or read book Problems of Calibration of Absolute Magnitudes and Temperature of Stars written by B. Hauck and published by Springer. This book was released on 1973-10-31 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: In connection with arranging IAU Symposium No. 50 on 'Spectral Classification and Multicolour Photometry', sponsored by Commissions 45 and 25, it was decided to exclude all calibration problems. Instead it was agreed that we should attempt to arrange a separate symposium, dealing with the fundamental problems of the cali bration of absolute magnitudes and temperatures of stars. The Executive Committee of the IAU accepted our proposal, and IAU Symposium No. 54 was held in Geneva on September 12-15, 1972, sponsored by thefollowing IAU Commissions: 24, 25, 29, 33, 35, 37,44 and 45. It was attended by about 90 scientists representing 16 countries. The Symposium was divided into eight sessions. Each session started with a review paper by an invited speaker; this was followed by a general discussion including a few contributed papers. The contents of the present volume follow closely the programmes of the individual sessions of the Symposium. Most of the recorded discussions have been kept, and only in a few cases have the order of questions and comments been altered so as to obtain more homogeneity in the presentation.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1967 with total page 978 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ultracool Dwarfs written by Hugh R.A. Jones and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt: Once you have looked at the night sky on a moonless night it is not hard to realise why so much of our science and religion has its roots in the stars. Yet it took until 1850 to realise that fainter stars were not necessarily further away, nor the brighter ones closer. In fact within the magnitude range observable to the naked eye it is probable that the brighter star is in fact further away. Even today the measurement of stellar distances is relatively difficult and is gener ally only done using dedicated telescopes. In the early years of the 20th century Hertzsprung and Russell developed a powerful classification diagram which al lows stars to be distinguished using a plot of their colour versus magnitude. The construction of this diagram involved the use of spectroscopy which has become the cornerstone of modern astronomy. As telescopes become more powerful, de tectors more sensitive and more physics is added to astrophysics, astronomical spectroscopy becomes a more powerful tool. The concern of this book is the spectral classification of stars. With a single spectrum of a star it is possible to uniquely classify an object and find its place on the Hertzsprung-Russell diagram. This spectrum is thus equivalent to having the colour and the magnitude of the object which can in turn be related to mass and other quantities.
Download or read book CRC Handbook of Metal Etchants written by Perrin Walker and published by CRC Press. This book was released on 1990-12-11 with total page 1434 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication presents cleaning and etching solutions, their applications, and results on inorganic materials. It is a comprehensive collection of etching and cleaning solutions in a single source. Chemical formulas are presented in one of three standard formats - general, electrolytic or ionized gas formats - to insure inclusion of all necessary operational data as shown in references that accompany each numbered formula. The book describes other applications of specific solutions, including their use on other metals or metallic compounds. Physical properties, association of natural and man-made minerals, and materials are shown in relationship to crystal structure, special processing techniques and solid state devices and assemblies fabricated. This publication also presents a number of organic materials which are widely used in handling and general processing...waxes, plastics, and lacquers for example. It is useful to individuals involved in study, development, and processing of metals and metallic compounds. It is invaluable for readers from the college level to industrial R & D and full-scale device fabrication, testing and sales. Scientific disciplines, work areas and individuals with great interest include: chemistry, physics, metallurgy, geology, solid state, ceramic and glass, research libraries, individuals dealing with chemical processing of inorganic materials, societies and schools.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 682 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physicochemical Treatment Processes written by Lawrence K. Wang and published by Springer Science & Business Media. This book was released on 2005-03-11 with total page 731 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past 30 years have seen the emergence of a growing desire worldwide to take positive actions to restore and protect the environment from the degrading effects of all forms of pollution: air, noise, solid waste, and water. Because pollution is a direct or indirect consequence of waste, the seemingly idealistic demand for “zero discharge” can be construed as an unrealistic demand for zero waste. However, as long as waste exists, we can only attempt to abate the subsequent pollution by converting it to a less noxious form. Three major questions usually arise when a particular type of pollution has been identified: (1) How serious is the pollution? (2) Is the technology to abate it available? and (3) Do the costs of abatement justify the degree of abatement achieved? The principal intention of the Handbook of Environmental Engineering series is to help readers formulate answers to the last two questions. The traditional approach of applying tried-and-true solutions to specific pollution pr- lems has been a major contributing factor to the success of environmental engineering, and has accounted in large measure for the establishment of a “methodology of pollution c- trol. ” However, realization of the ever-increasing complexity and interrelated nature of current environmental problems makes it imperative that intelligent planning of pollution abatement systems be undertaken.
Download or read book Advances in High Temperature Gas Cooled Reactor Fuel Technology written by International Atomic Energy Agency and published by . This book was released on 2012-06 with total page 639 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication reports on the results of a coordinated research project on advances in high temperature gas cooled reactor (HTGR) fuel technology and describes the findings of research activities on coated particle developments. These comprise two specific benchmark exercises with the application of HTGR fuel performance and fission product release codes, which helped compare the quality and validity of the computer models against experimental data. The project participants also examined techniques for fuel characterization and advanced quality assessment/quality control. The key exercise included a round-robin experimental study on the measurements of fuel kernel and particle coating properties of recent Korean, South African and US coated particle productions applying the respective qualification measures of each participating Member State. The summary report documents the results and conclusions achieved by the project and underlines the added value to contemporary knowledge on HTGR fuel.
Download or read book Women Writers and Old Age in Great Britain 1750 1850 written by Devoney Looser and published by JHU Press. This book was released on 2008-08-01 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: This groundbreaking study explores the later lives and late-life writings of more than two dozen British women authors active during the long eighteenth century. Drawing on biographical materials, literary texts, and reception histories, Devoney Looser finds that far from fading into moribund old age, female literary greats such as Anna Letitia Barbauld, Frances Burney, Maria Edgeworth, Catharine Macaulay, Hester Lynch Piozzi, and Jane Porter toiled for decades after they achieved acclaim -- despite seemingly concerted attempts by literary gatekeepers to marginalize their later contributions. Though these remarkable women wrote and published well into old age, Looser sees in their late careers the necessity of choosing among several different paths. These included receding into the background as authors of "classics," adapting to grandmotherly standards of behavior, attempting to reshape masculinized conceptions of aged wisdom, or trying to create entirely new categories for older women writers. In assessing how these writers affected and were affected by the culture in which they lived, and in examining their varied reactions to the prospect of aging, Looser constructs careful portraits of each of her Subjects and explains why many turned toward retrospection in their later works. In illuminating the powerful and often poorly recognized legacy of the British women writers who spurred a marketplace revolution in their earlier years only to find unanticipated barriers to acceptance in later life, Looser opens up new scholarly territory in the burgeoning field of feminist age studies.
