1,720,954 research outputs found
Conceptual design of a human mission to the near-earth asteroid 1999 AO10 in 2025-2026
No full textA human mission to the Near-Earth Asteroid (NEA) 1999 AOlO in 2025-2026 represents an intermediate and incremental step towards the human exploration of Mars. It would bring a large suite of benefits: high scientific return, operational experience on human space exploration missions beyond LEO, tests of technologies and assessment of human factors for future long-duration missions, tests of asteroid collision avoidance techniques and nevertheless evaluation of In-Situ Resource Utilization (ISRU). A space system modular architecture composed of 5 elements: 1 NASA Orion MPCV-like Command Module (CM), 1 Mission Habitation Module (MM) and 3 Propulsions Modules (PMl, PM2 and a Service Module SM of the CM), that use chemical storable cryogenic propulsion for the main orbital maneuvers (total ΔV = 7.23 km/s), is able to send in 2025-2026 a crew of 3 astronauts to the NEA 1999 AO10 for a space mission lasting 165 days, and bring them back safely to the Earth. The whole 5 modules Spacecraft (S/C) of almost 240 MT in total is launched separately by 2 equal crew and cargo Heavy Lift Launcher Vehicle (HLLV) of around 125 MT, still to be developed. The assembly in LEO anticipates the injection into the NEA Transfer Orbit (NTO) by the PMl, then expended. Once the S/C is in proximity of the asteroid, a rendez-vous maneuver is performed by the PM2, successively expended. Afterwards the MM, CM and SM attend a docking to a pre-installed platform, anchored on the NEA surface by a previous robotic mission. After 14 days of operations, including the deployment of instrumentation and the performance of high challenging EVAs, the remained 3 modules S/C come back to the Earth where the CM, with the crew on board, shall be able to land safely after an atmospheric direct re-entry. The S/C preliminary design includes the determination of S/C modules power budgets, the S/C elements interfaces functional analysis, the S/C subsystems definition and top-level functions allocation, nevertheless the assessment of preliminary single modules and whole space system mass budgets. The space human mission the NEA 1999 AO10 would be the first human expedition to an interplanetary body beyond the Earth-Moon system. The challenge of increasing the interest of the international community on the human spaceflight and inspiring the new generations about science, technology and space has been accepted. Copyright ©2011 by the International Astronautical Federation. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Development and manufacturing of high performance ribbons structures for the inflatable habitat module technology
No full textThe inflatable technology for space habitat modules is one of the most promising and beneficial technology in the field of human spaceflight. In fact inflatable deployable habitats will guarantee considerable volume and mass savings (in the order of more than 50%) at launch compared to the current applied metal-based solutions. The technology is based on several flexible layers composing the module structure able to provide one or more specific functions. The Structural Restraint, a seamed mesh of high performance ribbons, is the layer designated to sustain the loads generated from the difference between the module internal operative pressure and the external vacuum.
Within the STEPS2 project the consortium developed and manufactured a small representative segment of the Restraint (breadboard) to perform a biaxial tensile test and successively a cylindrical ground prototype for the system functional tests (folding and packing, deployment, inflation). The Restraint breadboard is composed of 4 longitudinal ribbons, 4 circumferential ribbons and all the 3 different properly qualified connection seams. The manufacturing process was previously studied and defined as well as the used tools. Specifically in order to determine the seaming sequence several trials were implemented on a dummy restraint made of PES ribbons with the same dimensions & configuration as the original one. In terms of tools two dedicated metal seaming masks were designed and manufactured. The process was preliminary implemented on the breadboard and then on the final cylindrical ground prototype.
The paper reports all the development and manufacturing steps and shows the obtained HW results including the biaxial tensile test outcomes
Variations on the Author
Full text link“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
Full text linkWe 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
Full text linkWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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