1,721,194 research outputs found
Kang Q Huat raih Hadiah Kecemerlangan Akademik Presiden Lembaga Jurutera Malaysia (LJM)
Get PDFGAMBANG, 26 Oktober 2024 – Graduan Ijazah Sarjana Muda (Kepujian) Kejuruteraan Awam, Kang Q Huat, 24, tidak menyangka akan terpilih selaku penerima Hadiah Kecemerlangan Akademik Presiden Lembaga Jurutera Malaysia (LJM) sempena Majlis Konvokesyen Universiti Malaysia Pahang Al-Sultan Abdullah (UMPSA) Ke-19
Kang Q Huat receives Board of Engineers Malaysia President’s Academic Excellence Award
Get PDFGAMBANG, 26 October 2024 – Bachelor of Civil Engineering with Honours graduate, Kang Q Huat, 24, never imagined he would be chosen as the recipient of the President’s Academic Excellence Award from the Board of Engineers Malaysia (BEM) during the 19th Convocation Ceremony of Universiti Malaysia Pahang Al-Sultan Abdullah (UMPSA)
Experimental and numerical study on capillary flow along deflectors in plate surface tension tanks in microgravity environment
No full textSurface tension tanks are the most widely used satellite propellant tanks, which use liquid surface tension for liquid transportation and gas-liquid separation to provide pure propellant for thruster. As the second generation surface tension tank, the plate type tank has characteristics of simple structure, easy processing and high reliability, and represents development direction of surface tension tanks. In this paper, drop tower experiments are used to investigate transfer speed of deflectors in plate type tanks, and corresponding numerical simulation is carried out in Fluent with Volume of Fluid method. (C) 2019 Author(s).</p
The impact of neutralizer-free ignition of a radio frequency ion thruster on the lifetime of the ion optics system
No full textIn the initial stage of a radio frequency ion thruster (RIT) ignition, an influx of electrons is required from an external source into the discharge chamber and ionization of the neutral gas propellant. A neutralizer-free method for Townsend breakdown discharge ignition based on Paschen's law was developed in this study. The feasibility of the ignition method was confirmed by performing thousands of ignition experiments. Metallic Molybdenum (Mo), pyrolytic graphite (PG) and Zr41.2Ti13.8Cu12.5Ni10Be22.2 alloy acceleration grids were prepared, and ignition-induced damage on the grids was investigated. A field-emission scanning electron microscope was used to inspect surface damage on the grids after multiple ignitions and to analyze the influence of the ignition method on the lifetime of the ion optical system. Grid materials for space missions that require multiple RIT ignitions (10(3)) should be high-strength blocks that are resistant to sputtering corrosion and high temperature.</p
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
Design of an Active Disturbance Rejection Control for Drag-Free Satellite
No full textThis paper addresses the problem of designing an active disturbance rejection controller for a high accuracy drag-free satellite with cubic test mass. The uncertain model of the drag-free satellite is defined. The performance requirement imposed on the acceleration of the test mass is broken down into specification of drag-free and suspension loop because of the disturbance decoupling controller, which is based on the linear active disturbance rejection control technique. We derive two-degree internal model control structure of ADRC, which is used for robust stability verification. Search programs determine the parameters that satisfy system stability and the performance requirement. The design technique has shown to be robust to the perturbation of the system and good performance in disturbance suppressing. To check the design of the controller, an overall simulation is preformed, and the results confirmed that the controller is able to meet the system requirements.</p
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
Raman-shifted wavelength-selectable pulsed fiber laser with high repetition rate and high pulse energy in the visible
No full textA high-pulse-energy, diffraction-limited, wavelength-selectable, visible source, based on Raman frequency shifting of a frequency-doubled Yb-doped fiber laser, has been studied. The relative length-scaling laws of Raman gain and self-phase modulation push the design towards short fiber lengths with large core size. It is experimentally demonstrated that the Raman clean-up effect in a graded-index multi-mode fiber is not sufficient to obtain diffraction-limited beam quality in the short fiber length. Thus, a large-core photonic crystal fiber is used to maintain diffraction-limited performance and output pulse energies of ~1 μJ, at a 1-MHz repetition rate and 1.3-ns pulse-width are successfully achieved. This step-tunable visible source should find applications in photoacoustic microscopy
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