470,445 research outputs found
Effects of component properties on the accuracy of a joint-dominated deployable mast
No full textJointed-dominated deployable masts are used in space applications, including telescopes, where there is a demand for a long, slender structure that can be packed into a conventional launch shroud. Depending on the application, there may be stringent demands on the stiffness and shape accuracy of the mast. This paper presents a parametric study of the significance of a number of mast part properties for a precision deployable mast's performance under quasi-static shear load. The mast's cable preload, latching system behavior, and joint friction are explored as candidates for parts requiring detailed characterization for accurate mast performance prediction. Copyright © 2011 by Sergio Pellegrino and Olive Stohlman
Repeatability of Joint-Dominated Deployable Masts
No full textDeployable masts are a class of structure that can be stowed in a small volume and expanded into long, slender, and stable booms. Their greatest benefit as space structures is their packing ratio: masts can typically be packed to a fraction of their deployed length at a diameter only modestly wider than their deployed width. This thesis is concerned with precision deployable masts, which can be stowed and deployed with repeatability of the tip position of better than 1 mm over 60 m. The methods of investigation are experimental measurements of a sample mast and numerical modeling of the mast with specially attention to hysteretic joints.
A test article of an ADAM mast was used for the experimental work. Two categories of experi- ment were pursued: measurements of mast components as inputs to the model, and measurements of full bays as validation cases for the model. Measurements of the longeron ball end joint friction, cable preload, and latch behavior are of particular note, and were evaluated for their variability. Further measurements were made of a bay in torsion and a short two-bay mast in shear, showing that there is residual displacement in this mast after shear loading is applied and released.
The modeling approach is described in detail, with attention to the treatment of the mast latches, which lock the structure in its deployed configuration. A user element subroutine was used within the framework of the Abaqus finite element analysis solver to model the behavior of the latches with high fidelity.
Validation cases for the model are presented in comparison with experimental observations of a two-bay mast. These cases show that the model captures a number of important and complex nonlinear effects of the hysteretic mast components. Parametric studies of the impacts of component behaviors and modeling practices are explored, emphasizing the impacts of part variability and the idealization of the mast latching mechanisms.</p
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Author headings for the official publications of the State of Kansas
No full textIncludes bibliographical references (page x).This list of author headings covers all official agencies as found in the laws of the territory and the laws of the state of Kansas from May 30, 1854 through July 1955; also agencies created by Executive Order, and administrative divisions, or boards, created within a department of the state. Agencies included are:
1. All departments, bureaus, divisions, commissions, courts, legislative bodies and special committees created by the laws or joint resolutions of the territory or state of Kansas, or by Executive Order*
2. Subdivisions of the respective departments, bureaus, commissions and committees even though not expressly created by acts of the legislature, but which are included in the official reports of the agencies*
3. Legislative bodies and their committees, if created by law, or if their reports were published.
4. Societies supported wholly, or in part, by the state.
5. All state and territorial institutions (including educational, charitable, correctional and penal)
Open access self-archiving: An author study
No full textThis, our second author international, cross-disciplinary study on open access had 1296 respondents. Its focus was on self-archiving. Almost half (49%) of the respondent population have self-archived at least one article during the last three years. Use of institutional repositories for this purpose has doubled and usage has increased by almost 60% for subject-based repositories. Self-archiving activity is greatest amongst those who publish the largest number of papers. There is still a substantial proportion of authors unaware of the possibility of providing open access to their work by self-archiving. Of the authors who have not yet self-archived any articles, 71% remain unaware of the option. With 49% of the author population having self-archived in some way, this means that 36% of the total author population (71% of the remaining 51%), has not yet been appraised of this way of providing open access. Authors have frequently expressed reluctance to self-archive because of the perceived time required and possible technical difficulties in carrying out this activity, yet findings here show that only 20% of authors found some degree of difficulty with the first act of depositing an article in a repository, and that this dropped to 9% for subsequent deposits. Another author worry is about infringing agreed copyright agreements with publishers, yet only 10% of authors currently know of the SHERPA/RoMEO list of publisher permissions policies with respect to self-archiving, where clear guidance as to what a publisher permits is provided. Where it is not known if permission is required, however, authors are not seeking it and are self-archiving without it. Communicating their results to peers remains the primary reason for scholars publishing their work; in other words,
researchers publish to have an impact on their field. The vast majority of authors (81%) would willingly comply with a mandate from their employer or research funder to deposit copies of their articles in an institutional or subject-based repository. A further 13% would comply reluctantly; 5% would not comply with such a mandate
Deorbitsail: A deployable sail for de-orbiting
No full textDeorbitsail is a collaborative project funded by the European Commission. The Deorbitsail Cubesat mission will demonstrate in-space deployment of a large thin membrane sail and drag deorbiting using this sail. The sail will be deployed from an 11-by-11-by-34-cm Cubesat platform, which will have 3-axis attitude control. A set of four gossamer booms will deploy four triangular membrane segments to form the 5-by-5-meter drag sail. The Deorbitsail design is intended for space debris prevention, although it holds potential for additional applications in aerobraking and solar sail propulsion. A 2014 launch is planned. This paper describes some of the high-level design and the ongoing engineering goals of the project. © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved
Measuring industry-science links through inventor-author relations: A profiling method
No full textIn this pilot study we examine the performance of text-based profiling in recovering a set of validated inventor-author links. In a first step we match patents and publications solely based on their similarity in content. Next, we compare inventor and author names on the highest ranked matches for the occurrence of name matches. Finally, we compare these candidate matches with the names listed in a validated set of inventor-author names. Our text-based profile methodology performs significantly better than a random matching of patents and publications, suggesting that text-based profiling is a valuable complementary tool to the name searches used in previous studies.innovation; industry-science links; text-based profiling;
Deorbitsail: A deployable sail for de-orbiting
No full textDeorbitsail is a collaborative project funded by the European Commission. The Deorbitsail Cubesat mission will demonstrate in-space deployment of a large thin membrane sail and drag deorbiting using this sail. The sail will be deployed from an 11-by-11-by-34-cm Cubesat platform, which will have 3-axis attitude control. A set of four gossamer booms will deploy four triangular membrane segments to form the 5-by-5-meter drag sail. The Deorbitsail design is intended for space debris prevention, although it holds potential for additional applications in aerobraking and solar sail propulsion. A 2014 launch is planned. This paper describes some of the high-level design and the ongoing engineering goals of the project. © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved
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