32,076 research outputs found
Letter from A. F. Potter to John H. Page
No full textLetter from A. F. Potter to John H. Page referring his request to build a railway to the District Forester at Albuquerque, New Mexico
Polly H. Carder Collection on George F. Root
No full textGeorge Frederick Root (1820-1895) was an American songwriter and music educator. He is perhaps best known for his song "The Battle Cry of Freedom," which was written and rose to popularity during the U.S. Civil War. The Polly H. Carder Collection on George F. Root contains original published scores and songbooks from the period 1852-1907 and photocopied scores collected by Polly H. Carder, author of the book George F. Root, Civil War Songwriter: A Biography. The collection also contains a short article, "The Last Days of George F. Root," written by Root's daughter, Clara Louise Burnham
Achievements in the design of thin-walled composite structures
No full textAerospace and space industry strives for significantly reduced development and operating costs. Reduction of structural weight at safe design is one possibility to reach this objective. Another one is the use of reliable simulation methods in order to minimize expensive and time consuming experimental design studies. The presentation shows examples on new achievements in the design of thin-walled composite structures of the buckling and the postbuckling behaviour of thin-walled structures up to collapse, respectively, which allow the exploitation of considerable reserves in primary fibre composite structures in aerospace applications.
Investigation of the postbuckling behaviour of stiffened composite aerospace structures
This part demonstrates experimental and numerical studies of axially loaded stringer-stiffened thin-walled composite structures in the postbuckling area. The structures considered are undamaged and pre-damaged. They are loaded in a first step by several cyclic loading just before collapse to investigate the damage growth of such structures. In the last step the structures are loaded in one step until collapse. During the experiments advanced measurement systems [1] with high-speed cameras (ARAMIS), thermography and lamp-waves were applied to take as much information as possible from the experiments. The presentation gives examples from various test results and comparison numerical simulations [2,3,4].
Fast simulation tool for the simulation of unstiffened cylindrical and conical composite structures
A new semi-analytical method capable to predict the static and the instability response of the non-linear buckling of unstiffened laminated composite cones and cylinders under various loads and boundary conditions is presented. The tool considers geometric and load imperfections. The Ritz method is selected to solve the non-linear set of equations and a new set of appropriate approximation functions for the displacement field is proposed, in order to simulate axial compression, torsion, pressure, load asymmetry, any arbitrary surface or concentrated loads, and any load case combining these loads. Elastic constraints are used to produce a wide range of boundary conditions, covering the four types of boundary conditions commonly used in the literature. For conical shells a novel approximation is proposed in order to efficiently perform the analytical integration of the linear stiffness matrices. A detailed convergence analysis is presented and the proposed models are verified with finite element results, models available from the literature and test results [5-7].
Numerical assessment of existing vibration correlation techniques
The buckling of real space structures is challenging to validate as the first failure in the experiment might be material and not buckling as predicted. One reason is the high imperfection sensitivity of such thin-walled structures. There is therefore a high need for non-destructive methods to calculate the buckling. The Vibration Correlation Technique (VCT) allows determining the buckling load without reaching the instability point. Here, the structures will be loaded at different load steps. In each step the structures is broad into vibrations and the eigenfrequencies are measured. The relation between the load and the first (or higher) eigenfrequency is nonlinear. There exist several methods to predict the buckling of different type of structure (beam, plate, shell) or material based on this nonlinear dependence. In 2014, Arbelo developed a promising method for cylindrical shells [8]. This presentation explores further the novel approach and compares the results with other available VCT methods through numerical Finite Element (FE) simulations.
[1]. Degenhardt R., Kling A., Klein H., Hillger W., Goetting Ch., Zimmermann R., Rohwer K., Gleiter A., “Experiments on Buckling and Postbuckling of Thin-Walled CFRP Structures using Advanced Measurement Systems”, International Journal of Structural Stability and Dynamics, Vol. 7, No. 2 (2007), pp. 337-358
[2]. Degenhardt R., Kling A., Rohwer K., Orifici A. C., Thomson R. S., “Design and Analysis of Stiffened Composite Panels Including Postbuckling and Collapse”, Computers and Structures Vol. 86 (2008), pp. 919-929
[3]. Degenhardt R., Wilckens D., Klein H., Kling A., Hillger W., Goetting Ch., Rohwer K., Gleiter A., “Experiments to detect the damage progress of axially compressed CFRP panels under cyclic loading”, Special volume of Key Engineering Materials Vol. 383 (2008) pp 1-24
[4]. Wilckens D., Degenhardt R., Rohwer K., R., Zimmermann R., Kepke M., Hildebrandt B., Zipfel A., “Cyclic buckling tests of pre-damaged CFRP stringer stiffened panels”, International Journal of Structural Stability and Dynamics, Vol. 10, No. 4 (2010), pp. 827-852
[5]. Castro S., Mittelstedt C., Monteiro F., A. Arbelo M., Ziegmann G., Degenhardt R., Linear buckling predictions of unstiffened laminated composite cylinders and cones under various loading and boundary conditions using semi-analytical models, Int. Journal of Composite Structures, Vol. 118 (2014), pp. 303-315
[6]. Castro S., Mittelstedt C., Monteiro F., A. Arbelo M., Degenhardt R., “A semi-analytical approach for the linear and non-linear buckling analysis of imperfect unstiffened laminated composite cylinders and cones under axial, torsion and pressure loads “, Int. Journal of Thin-Walled Structures, Vol. 90 (2015) pp. 61–73
[7]. Castro S., Mittelstedt C., Monteiro F., Ziegmann G., Degenhardt R., Evaluation of non-linear buckling loads of geometrically imperfect composite cylinders and cones with the Ritz method, Int. Journal of Composite Structures, 10.1016/j.compstruct.2014.11.050
[8]. M. A. Arbelo, S. F. M. de Almeida, M. V. Donadon, S. R. Rett, R. Degenhardt, S. G. P. Castro, K. Kalnins und O. Ozoliņš, „Vibration correlation technique for the estimation of real boundary conditions and buckling load of unstiffened plates and cylindrical shells,“ Thin-Walled Structures, Bd. 79, pp. 119-128, 2014
Electron and positron scattering from 1,1-C₂H₂F₂
No full text1,1-difluoroethylene (1,1-C₂H₂F₂) molecules have been studied for the first time experimentally and theoretically by electron and positron impact. 0.4-1000 eV electron and 0.2-1000 eV positron impact total cross sections (TCSs) were measured using a retarding potential time-of-flight apparatus. In order to probe the resonances observed in the electron TCSs, a crossed-beam method was used to investigate vibrational excitation cross sections over the energy range of 1.3-49 eV and scattering angles 90 degrees and 120 degrees for the two loss energies 0.115 and 0.381 eV corresponding to the dominant C-H (ν₂ and ν₉) stretching and the combined C-F (ν₃) stretching and CH₂ (ν₁₁) rocking vibrations, respectively. Electron impact elastic integral cross sections are also reported for calculations carried out using the Schwinger multichannel method with pseudopotentials for the energy range from 0.5 to 50 eV in the static-exchange approximation and from 0.5 to 20 eV in the static-exchange plus polarization approximation. Resonance peaks observed centered at about 2.3, 6.5, and 16 eV in the TCSs have been shown to be mainly due to the vibrational and elastic channels, and assigned to the B₂, B₁, and A₁ symmetries, respectively. The pi* resonance peak at 1.8 eV in C₂H₄ is observed shifted to 2.3 eV in 1,1-C₂H₂F₂ and to 2.5 eV in C₂F₄; a phenomenon attributed to the decreasing C=C bond length from C₂H₄ to C₂F₄. For positron impact a conspicuous peak is observed below the positronium formation threshold at about 1 eV, and other less pronounced ones centered at about 5 and 20 eV.The work was supported in part by a Grant-in-Aid, the
Ministry of Education, Science, Technology, Sport and Culture,
Japan, the Japan Society for the Promotion of Science
JSPS, and the Japan Atomic Energy Research Institute
JAERI. One of the authors C.M. is also grateful to the
JSPS for financial support under Grant No. P04064. Another
author H.T. acknowledges Dr. T. Ozeki of the JAERI for
his encouragement and support during this work. This work
was also done under the International Atomic Energy Agency
IAEA project for three of the authors C.M., M.H., and
H.T.. Two of the authors M.H.F.B. and M.A.P.L. acknowledge
support from the Brazilian agency Conselho Nacional
de Desenvolvimento Científico e Tecnológico CNPq.
MHFB also acknowledges support from the Paraná state
agency Fundação Araucária and from FINEP ( under Project
No. CT-Infra 1)
„f“ AND „h“ LETTERS\u27 PROBLEM IN LATGALIAN LANGUAGE
No full textIn the article is told about the problem of letters’ (and sounds’) f and h in Latgalian language. These sounds have never been in any Latgalian dialect, in foreign words speakers always have been replaced them with other sounds. At the same time letters f and h have been used in written Latgalian at all times: from the first known book „Evangelia toto anno“ to the present day. What to do in this situation: to keep the way of the still alive traditional spoken language, or to yield to the pressure of other languages?The author analyzes a variety of sources: tells about reconstructions of source languages and opinions of their researchers about presence/absence of these sounds in them, deals with f in contemporary Eurasian languages (Eastern Slavic: Russian, Ukrainian, Belarusian; Finnic: Finnish, Estonian, Vyru; Turkic: Kyrgyz, Kazakh, Chuvash, Yakut; Persian: Pashto; Baltic: Lithuanian, Samogitian) and h in contemporary Eurasian languages (French, Kazakh, Lithuanian, Samogitian). Latgalian and Latvian dialects’ recordings, folk songs, ancient texts (from XVI–XVIII centuries), as well as Latgalian contemporary literature are analyzed. The author also evaluates inclusion of letters f and h in alphabet of the official Latgalian terms of spelling in year 2007.Author establishes that there are five possible paths:1) to use the f and h in all the words where they are in Latvian, Russian or other languages;2) to keep p, k, g and c in traditionally used words, but to put f and h in newly borrowed ones;3) do not use the f and h at all;4) to use both variants parallely in the same words;5) to write f and h, but to pronounce them as p and k.Author concludes that the actualy usable are only two of them: the second one – the way of a compromise, and the third one – as the most appropriate to Latgalian phonological system
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
IR-IR DOUBLE RESONANCE EXPERIMENT OF CHF-(-H) CLUSTERS IN SOLID -H
No full textAuthor Institution: Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka Okayama 700-8530 JAPAN; Department of Physics, Tokyo Institute of Technology, Tokyo, 152-8551 JAPANFTIR absorption spectrum of the \nu vibrational band of CHF in solid -H shows a series of lines at regular intervals, which could be assigned to clusters forming CHF-(-H), with n = 0 to 12 nderline{119}, 4731(2003)}. However, such a distinct feature appears only in the \nu mode but is not observed in the other vibrational modes. In order to solve this problem, we applied IR-IR double resonance spectroscopy using 3 m OPO laser and 9 m QC laser to the vibrational bands of CHF in solid -H. Because, very recently, high resolution cw-QC laser spectroscopy demonstrated a perfect bleaching effect on a spectral peak in \nu mode, nderline{13}, 11587 (2011)}. By bleaching the n=1 component of the \nu band at 9 m, we can see a corresponding depletion in the broad spectral feature of the \nu band at 3 m. This simultaneous disappearance of the spectral peaks is a proof of the CHF-(-H) cluster model, and it suggests that all the vibrational bands should be explained by the same model
Contribution of Information and Communication Technology (ICT) in Country’S H-Index
No full textThe aim of this study is to examine the effect of Information and Communication Technology (ICT) development on country’s scientific ranking as measured by H-index. Moreover, this study applies ICT development sub-indices including ICT Use, ICT Access and ICT skill to find the distinct effect of these sub-indices on country’s H-index. To this purpose, required data for the panel of 14 Middle East countries over the period 1995 to 2009 is collected. Findings of the current study show that ICT development increases the H-index of the sample countries. The results also indicate that ICT Use and ICT Skill sub-indices positively contribute to higher H-index but the effect of ICT access on country’s H-index is not clear
The construction of Karen Karnak: The multi-author-function
No full textThis thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author
Rockerville CCC Camp F-10
No full textCaption: "#41d, Summer 1934. Author: E. H. Mason. Rockerville CCC Camp F-10, Company 1794. General view of the camp showing portable buildings 20' x 80' and log buildings in background.
- …
