1,720,988 research outputs found
METHOD AND SYSTEM FOR MANUFACTURING EXPANDED STRUCTURE USING RESIN-INFUSION CURING AND AVALIABLE IN SPACE
No full text우주 공간에서 이용가능한 수지 침투 경화를 이용한 확장 구조물 제조 방법은, 기압차를 이용하여 접혀진 섬유 백을 팽창시키는 단계, 상기 섬유 백의 외피층과 내피층 사이에 배치된 섬유층에 수지 조성물을 확산시키는 단계 및 상기 수지 조성물을 경화하는 단계를 포함한다
Space radiation and hypervelocity impact shielding for low earth orbit space structures using ultrahigh-molecular-weight polyethylene
No full textSpace radiation is defined as particle radiation consisting of protons, heavy ions, and electrons. Space radiation has a catastrophic effect on satellite electronics and reduces its lifespan. It also greatly limits the performance of satellite electronics. It makes it impossible for astronauts to stay in space for long-term because of the potential of various diseases and cancer. Polyethylene is known to perform very well in space radiation shielding. In particular, ultra- high- molecular- weight polyethylene (UHMWPE) has very high mechanical performance. Meanwhile, there are millions of space debris in Earth's orbit now. These debris have hypervelocity impact of several tens of km/s depending on the orbit and thus threaten the survival of space structures. In the case of International Space Station, the concept of Whipple shield, a dual aluminum protection system, is applied to protect the astronaut from impact of space debris. In this study, space radiation shielding and hypervelocity impact performance of proposed space structure system with ultra- high- molecular- weight polyethylene is investigated. Cyclotron was used for proton irradiation test. Also, a two stage light gas gun was used for hypervelocity impact test. The UHMWPE showed better performance in space radiation shielding and hypervelocity impact than Kevlar
Ultra-high-molecular-weight polyethylene/hydrogen-rich benzoxazine composite with improved interlaminar shear strength for cosmic radiation shielding and space environment applications
No full textCommercial off-the-shelf is being used as an electronic device for high-performance, low-cost satellites but is vulnerable to cosmic radiation. UHMWPE/hydrogen-rich benzoxazine composite (UHC) exhibits excellent cos-mic radiation shielding. However, the low interfacial adhesion of UHMWPE causes low flexural strength and delamination of the UHC. We increased the interlaminar shear strength of UHC via polydopamine coating, MWCNT, and amine grafting on UHMWPE. The total mass loss and collected volatile condensable material tests were performed on the UHC to confirm for space environmental suitability. The proposed material is expected to be utilized as a cosmic radiation shielding panel for future satellites.N
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Tubular laminated composite structural battery
No full textThis paper introduces a polymer-matrix composite-based structural lithium-ion battery system with tubular morphology. Its shape and closed cross-section, fabricated during the autoclave process, allow for high electrochemical performance by controlling the electrode distance and battery environment. To prevent the degradation of the organic liquid electrolyte within this continuous resin polymer system, extra components such as thermoplastic hot melt film, a double glass load-bearing separator, aluminum film, and polydimethylsiloxane were implanted. The electrochemical properties of this manufactured multi-functional structural battery design, named the tubular laminated composite battery (TLCB), were tested with a galvanic cell testing machine. The initial specific capacity of TLCB was found to be approximately 120-130 mAh/g with good cycling performance and steady coulombic efficiency. Furthermore, mechanical load resistance and correlation with electrochemical performance were also assessed under the four-point bending load condition. These results show that the TLCB has the potential to operate as a subsidiary energy storage for future electric vehicle systems with a certain level of structural specific capacity and load-bearing properties.
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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