18,575 research outputs found
Turbulent skin-friction drag reduction by travelling waves induced by spanwise Lorentz force
No full textThe streamwise and spanwise travelling waves induced by spanwise Lorentz force are studied for skin-friction drag reduction in a turbulent channel. The streamwise travelling wave by spanwise Lorentz force on drag reduction is compared to the with the spanwise wall motion. The drag reduction map shows a drag reduction region and a drag increase region, depending on a time scale . For spanwise travelling wave, a large drag reduction appears at large oscillation frequencies and small spanwise wave numbers, while all stationary wave cases give a drag increase. When the wave travels at an oblique angle to the streamwise mean flow, the optimal drag reduction appears in backward travelling wave case. Generally, the backward streamwise travelling wave is found to be most efficient in drag reduction among all oblique travelling waves. Spanwise oscillation, forward streamwise travelling, spanwise travelling and backward streamwise travelling wave cases share a similar drag reduction mechanism: first, the spanwise motion directly breaks the near wall quasi-streamwise vortices structure array \cite{Jeong_etal1997}, which results in the shortening of streamwise streaks; second, the spanwise velocity layer maintains the asymmetry of the positive and negative quasi-streamwise vortices, which leads to a sustained drag reduction
Sedum triangulisepalum T. S. Liu & N. J. Chung ex T. C. Hsu & S. W. Chung 2022, sp. nov.
No full text<p> <i>Sedum triangulisepalum</i> T.S. Liu & N.J. Chung ex T.C. Hsu & S.W. Chung, <i>sp. nov.</i></p> <p> [“ <i>Sedum triangulisepalum</i> T.S. Liu & N.J. Chung (1977: 21, as <i>triangulosepalum</i>)”, <i>nom. inval.</i>; “ <i>Sedum triangulisepalum</i> T.S. Liu & N.J. Chung ex H.W. Lin (1999: 102, as <i>triangulosepalum</i>)”, <i>nom. inval.</i>; “ <i>Sedum triangulisepalum</i> T.S. Liu & N.J. Chung ex S.W. Chung ” in Chen <i>et al.</i> (2017: 329, as <i>triangulosepalum</i>), <i>nom. inval.</i>].</p> <p> <b>Type:</b> — TAIWAN. Hualien County: Hsiulin Township, Lo-ma-wan Shan, 1800 m elev., 15 June 1973, <i>N.J. Chung 280</i> (holotype: NTUF!, barcode: F00008307; isotypes: NTUF!, eight sheets, barcodes: F00008308–F00008315).</p> <p> <b>Diagnosis:</b> — <i>Sedum triangulisepalum</i> is similar to <i>S. truncatistigmum</i> T.S. Liu & N.J. Chung (1977: 23) in sharing epiphytic life-form, alternate and ±flattened leaves and fused calyx, while the former is readily distinguished in having longer calyx (1.5–2.0 vs. 0.8–1.0 mm) that are only fused at the base (vs. nearly entirely fused).</p> <p> <b>Morphological descriptions and illustrations:</b> —This species has been described by Liu & Chung (1977: 21) and illustrated by Tang & Huang (1989: 27, pl. 15, as <i>Sedum microsepalum</i>), Chen <i>et al.</i> (2017: 329) and Ito <i>et al.</i> (2017: 11, fig. 1D).</p> <p> <b>Distribution and ecology:</b> — <i>Sedum triangulisepalum</i> is endemic in Taiwan, where it occurs in the northern and eastern portions of the main island and usually grows on tree trunks in montane cloud forests at 500–2000 m elev. (Liu & Chung 1977; Chen <i>et al.</i> 2017; Ito <i>et al.</i> 2017).</p> <p> <b>Etymology:</b> —The specific epithet is composed of two Latin elements: <i>triangulus</i>, triangular, and <i>sepalum</i>, sepal, referring to its triangular calyx lobes. It should be spelt as “ <i>triangulisepalum</i> ” instead of “ <i>triangulosepalum</i> ” as originally published by Liu & Chung (1977) according to Art. 60.10 of the ICN.</p> <p> <b>Note:</b> —Two gatherings, “ <i>Suzuki s.n.</i> ” collected from Wulai and “ <i>Chuang 280</i> ” collected from Lomawanshan, were cited under <i>Sedum triangulisepalum</i> by Liu & Chung (1977), and “ <i>Chuang 280</i> ” is presumably a typo of “ <i>Chung 280</i> ” since the “ <i>N.J. Chung 280</i> ” gathering, collected by the second original author and currently preserved in NTUF, matches well with the data given in the original publication (Liu & Chung 1977). There are nine duplicates of <i>Chung 280</i>, including one (barcode: F00008307) labelled as “ holotype ” and the others (barcodes: F00008308–F00008315) as “isotype”. Although these labels could not be archived as the legitimate designation of types as they are not effectively published (see Art. 7.10 of the ICN), they supposedly reflect the original author’s intention and are thus adopted here. Images of all type materials are available in the “Plants of Taiwan ” database [http://tai2.ntu.edu.tw].</p>Published as part of <i>Hsu, Tian-Chuan & Chung, Shih-Wen, 2022, Validation of the name Sedum triangulosepalum (Crassulaceae), pp. 215-216 in Phytotaxa 547 (2)</i> on page 215, DOI: 10.11646/phytotaxa.547.2.10, <a href="http://zenodo.org/record/6571375">http://zenodo.org/record/6571375</a>
Turbulent structures in unsteady wall-bounded flow subject to temporal acceleration
No full textDirect numerical simulations (DNS) of a transient turbulent channel flow subject to constant temporal acceleration have been performed with a final Reynolds number of \Retau=800. The response of turbulent structures to the temporal acceleration is investigated. A significant delay in the response of turbulent flow is observed in various turbulent properties. It is found that the response of turbulent flow to temporal acceleration consists of two stages: the destruction of the initial \emph{old} turbulence, followed by the generation of \emph{new} turbulence associated with a higher number. The \emph{new} turbulence is much stronger than the \emph{old} turbulence
The political role of the people's liberation army 1949-1973
No full textThis thesis is to study the political role of the People's Liberation Army from the approach of structure and function. The framework of the thesis consists of three major parts, first, the influence of Chinese traditional political culture on, and the formation of, the political role of the PL A; second, the influence of domestic political struggles and external military conflicts on the development of the political role of the PLA; and the third, the analysis of the transition of the PLA's political role from the structure and personnel arrangements of the CCPCC Within the above-mentioned three scopes, this thesis make a thorough discussion on the following: (1) The relationship between the structure of the PRC and the formation of the PLA's political role; (2) How has ideology influenced the army's political role; (3) What is Mao's viewpoint and his influence on the development of the army's political role; (4) What is the link between the army and the party, and how has this developed; (6) What accounts for the expansion of the PLA's political functions; (7) What is the influence of political factional struggles on the PLA's political role; (8) Is it political institution or military institution that controls the recruitment of the military elite; (9) What are the disparities between the military elite in handling international conflicts and what are their political considerations; (10) What is the Party's position in the army; (11) How have the Party’s important meetings and personnel arrangements influenced the rise and fall of the PLA's political role
Concentration in Knowledge Output: A case of Economics Journals
No full textThis paper assesses the degree of author concentration in seven economics journals, which were published in India during 1990-2002. To measure the degree of author concentration, Lotka's Law was used. Moreover, we also make an exploratory analysis of the geographic, economics subfield and institutional concentration in 704 economics journals. An important finding of this paper is that specialized journals in the sample report the highest degree of author concentration. This result is quite similar to the findings by Cox and Chung (1991). Furthermore, there are several instances showing that the journals lean towards certain norms; this may affect the flow of innovative ideas into economics. We conclude that a knowledge activity, involving the high degree of concentration and a biased publication process, may affect the flow of new ideas into the discipline.Concentration, Lotka's Law
American Image of President Park Chung-hee of the Republic of Korea: Park Chung-heeas Death and American Newspapers
No full textSouth Korea s President Park Chung-hee was still a controversial figure in Korean history He was a man who achieved the economic miracle of South Korea while adopting repressive measures to suspend the democracy and human Korea The nostalgia of Park s era also remains Park receives fairly good evaluations from the world American newspapers at the death of Park Chung-hee provided the objective views on Park Chung-hee Throughout the newspapers editorials Park was the man who brought the economic miracle of South Korea and a good ally for the U S at the time of Cold War On the other hand he was another dictator who enjoyed autocratic rule under the U S protection The American views provide the foundation to evaluate Park Chung-hee of toda
A Functional Analysis of Tone
No full textThe tonal patterns of a Korean dialect spoken in Taegu area have been analyzed from a functional point of view. The author claims that two underlying functional accents Polarizing (P) and Leveling (E) can derive all derive all the surface patterns by the following rules:
1. a. (U) P (U) (L)H (L)
b. (U) E (U) (L)H (H)
2. a. (U)PE (U)PU
b. (U)PP (U)UP
c. (U)E { P } (U)EU
E
Thus P produces polarizedpatterns such as HL, LH; E produces leveledpatterns
such as HH; and these two kinds of patterns constitute an optimal functional contrast.
(For more details, see Chung (1980) given in the References on p. 48.
A new filter design for airborne disease transmission
No full textSubmission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2023-12-01The student, Chun-I Chung, accepted the attached license on 2021-12-07 at 01:36.The student, Chun-I Chung, submitted this Thesis for approval on 2021-12-07 at 01:36.This Thesis was approved for publication on 2021-12-07 at 14:12.DSpace SAF Submission Ingestion Package generated from Vireo submission #17207 on 2022-04-06 at 17:16:50Made available in DSpace on 2022-04-29T21:45:53Z (GMT). No. of bitstreams: 2
CHUNG-THESIS-2021.pdf: 2180043 bytes, checksum: bf1c79cd39ae5c4da16e5c3aa024190b (MD5)
LICENSE.txt: 4209 bytes, checksum: 0e13b133054416fb5d06c5bcf1fda296 (MD5)
Previous issue date: 2021-12-07Embargo set by: Seth Robbins for item 123327
Lift date: 2024-04-29T21:46:25Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 123327
Lift date: 2024-04-29T21:47:53Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemAuthor requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I OnlyTwo particle filters were designed using a vortex trap concept with equally spaced channels and tortuous airflow paths. A small wind tunnel was built to evaluate the filters’ efficiency under various conditions. Emphasis is placed on the effect of the following parameters, namely, tortuosity, T = 1.3 and 2.0, square conduit size of 0.4 mm and 0.7 mm, and incoming flow velocity U =0.2 m/s and 0.4 m/s. Results show that a particle size on the order of 10 μm passing through a two-layer filter with T = 2 and square-hole size of 0.7 mm width provide 98.5% efficiency
- …
