• 제목/요약/키워드: length scales

검색결과 299건 처리시간 0.027초

MHD turbulence in expanding/collapsing media

  • 박준성;류동수;조정연
    • 천문학회보
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    • 제36권1호
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    • pp.85.2-85.2
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    • 2011
  • We investigate the driven magnetohydrodynamic (MHD) turbulence by including the effect of the expansion and collapse of background medium. The main goal is to quantify the evolution and saturation of the strength and characteristic length scales of magnetic fields in expanding and collapsing media. Our findings are as follows. First, with the expansion and collapse of background medium, the time evolution of the magnetic and kinetic energy densities depends on the nature of forcing as well as the rate of expansion and collapse. Second, at scales close to the energy injection (or driving) scale, the slope of magnetic field power spectrum shallows with expansion but steepens with collapse. Third, various characteristic length scales, relative to the energy injection scale, decrease with expansion but increase with collapse. We discuss the astrophysical implications of our results.

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헤어스타일.길이와 모자유형이 인상형성에 미치는 영향 (The Effect of Hair-style.Hair-length and Types of Hat design on Impression Formation)

  • 정해선;강경자
    • 한국의류학회지
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    • 제28권3_4호
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    • pp.460-471
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    • 2004
  • The purpose of this study is to investigate the effect of hair-style (straight and wave), hair-length(short, medium, and long), and type of hat design (no-hat, beret, cloche, bowler, and capeline) on impression formation. The experimental materials developed for this study were a set of stimulus and response scales. The 7-point semantic differential response scales were designed. Thirty stimuli color pictures of various combination of hair length, hair style, and type of hat design were manipulated by computer drawing. The subjects were 360 undergraduates living in Seoul, Kyunggi and Kyungnam. The experimental design was composed of 3 factorial designs. The result of the study can be summarized as follows; Impression factor of the stimulus consisted of the 5 different dimensions (attractiveness, gracefulness, activity, concentration of attention, cuteness). Hair style greatly affected gracefulness. On the other hand, hair length made remarkable effects on attractiveness, concentration of attention, and cuteness. In addition, it has been found that the type of hat design significantly influenced on all the factors except attractiveness as independent variables. In regarding the effect of interaction between each variable, the combination of hair style and hair length had significant effects on gracefulness. In the impression formation of cuteness, the combination of hair length and type of hat design were more significant.

플레어스커트의 시각적 평가를 위한 의미미분척도 개발 (A Study on Development of Semantic Differential Scales for Visual Evaluation of Flare Skirt)

  • 이정순;한경희
    • 패션비즈니스
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    • 제13권1호
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    • pp.91-101
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    • 2009
  • The purpose of this study is to develop semantic differential scales which are necessary to evaluate visual image and effect of flare skirt. As a result of the first survey of 362 female college students, the most effective factors for shape of flare skirt are silhouette, volume of flare, and skirt length. Based on this result, we made flare skirt simulation for visual evaluation with using I-Designer program. 4 kinds of volume of flare($90^{\circ},\;180^{\circ},\;270^{\circ},\;360^{\circ}$) and 3 kinds of skirt length(48cm, 58cm, 68cm) are combined as variables for flare skirt of visual evaluation. For the second survey of 362 female college students, we asked to write suggested adjectives freely. As a result, we could draw out 210 adjectives. 'Feminine' was most frequently used word for flare skirt, and then, 'vivid', 'rhythmic', 'cute', 'soft', 'fat', and 'comfortable' in this order. With considering frequently used words in the preceding study, we selected 41 adjectives. Antonyms were selected from the resulted frequency of this study and preceding study, and the rest of words were found from dictionary. From these process, we developed semantic differential scales for visual image and effect of flare skirt.

Population persistence of the perennial kelp Eisenia arborea varies across local spatial scales

  • Gossard, Daniel J.;Steller, Diana L.
    • ALGAE
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    • 제37권1호
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    • pp.63-74
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    • 2022
  • Perennial stipitate kelps are globally distributed and individual species can inhabit broad latitudinal ranges, expressing notably longevous persistence. Despite the foundational role kelps provide to their communities, little is known about the variability in persistence of the stipitate kelps at local spatial scales. We studied the population persistence of Eisenia arborea, a heat- and wave force-tolerant perennial stipitate kelp with a distributional range extending from British Columbia to south of the range limit of all other northeast Pacific kelps, in Baja California Sur, Mexico. Persistence characteristics for E. arborea among sites were compared and used to test the hypothesis that stand persistence varied at local spatial scales around Isla Natividad, a Pacific island off the Baja California peninsula with documented spatiotemporal environmental heterogeneity. Collected individuals around the island were "aged" using the previously validated age estimation technique of counting annual cortical dark rings. After detecting no significant differences among sites in the covariation between estimated ages for collected individuals and stipe length, we utilized in-situ population-level stipe length measurements to more rapidly predict age structures within six stands around the island. Predicted age structures, and associated stand densities, revealed persistence characteristics and density varied at local scales and a strong positive relationship existed between stand density and stand mean and maximum ages. We speculate that stands responded differently to deterministic influences (e.g., the 2014-2016 marine heatwave and / or competition with Macrocystis) resulting in heterogenous local persistence of this foundation species.

Modified Equation for Predicting the Radius of Assembled Superstructures Made of Nanowires Including Polypyrrole Segment of All Length Scales

  • Lim, Jong-Kuk
    • Bulletin of the Korean Chemical Society
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    • 제33권8호
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    • pp.2699-2702
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    • 2012
  • Gold-polypyrrole segment nanowires prepared using anodized aluminum oxide templates can be assembled into a curved superstructure that shows stimuli-induced contraction and expansion. The radius of the superstructures can be predicted using the simple equation suggested by J. K. Lim et al. (Nano Lett. 8, 4441 (2008)). The suggested equation, however, is valid only within the limiting condition in that the length of the polypyrrole segment is comparable to, or much longer than the gold segment. In this study, the original equation was modified to a new equation that is valid for all length scales of polypyrrole segments. The radius of the superstructures calculated using the modified equation was compared with the result calculated by the original equation, and the validity of the modified equation is discussed.

음성 Sample의 길이 변화에 따른 MDVP 측정치와 GRBAS 척도간의 상관관계 변화 비교 (The Change of the Correlation between GRBAS Scales and MDVP Parameters according to the Different Length of Voice Samples for MDVP Analysis)

  • 표화영;심현섭;임성은
    • 음성과학
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    • 제7권2호
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    • pp.71-81
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    • 2000
  • The present study was performed to find efficient and useful length of voice sample for MDVP analysis, by investigating the correlation between perceptual GRBAS scales and objective MDVP measurements, with the five different lengths of voices of 20 patients with vocal polyp: 0.5, 1.0, 1.5, 2.0, 2.5 seconds. The results are following: (1) 1.5-second sample of MDVP showed the highest correlation between the perceptual judgement and objective measurement, and 1.0-second sample showed the lowest. The difference between the two samples was found in the number of the statistically significant correlated pairs of MDVP parameter-GRBAS scale. (2) The two extreme edges of the lengths, 0.5-second and 2.5 second showed no statistically significant difference.

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Myxobolus episquamalis (Myxosporea: Myxobolidae) on the scales of wild mullet, Mugil cephalus L, in Korea

  • 조재범;허민도;김기홍;권세련;이무군
    • 한국어병학회지
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    • 제19권1호
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    • pp.1-6
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    • 2006
  • Numerous large whitish cysts were found on the scale of wild mullet, Mugil cephalus captured in Jin-Hae bay of southern coastal sea of Korea. The cyst consisted of many trophozoites, mature spores and interstitial tissues of host origin. Spores were 8.25 ㎛ (7.26-9.35) in length, 6.3 ㎛ (5.63-6.78) in width, 4.34 ㎛ (3.96-5.04) in thickness. Polar capsules were 4.45㎛ (3.8-5.4) in length and 2.35 ㎛ (1.62-2.86) in width, and the length of polar filament was about 39.57 ㎛ (26.3-56.33). Based on the spore morphology and the host & tissue specificity, the present specimens were identified as Myxobolus episquamalis Egusa, Maeno & Sorimachi, 1990. Deformation of bony plate of the scales and infiltration of inflammatory cells were observed in the histological sections.

엔진 난류의 크기척도 및 에너지 스펙트럼 해석 (Analysis of Turbulence Scales and Energy Spectrum for Engine Flows)

  • 강건용;이진욱;박승철
    • 대한기계학회논문집B
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    • 제22권9호
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    • pp.1307-1316
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    • 1998
  • Engine turbulences obtained by LDV measurement near the compression TDC was analyzed by the classic turbulence theory. Turbulences were quantified by a cycle resolved analysis and processed to reveal integral time scale and length scale. Three different definitions were applied to obtain the turbulence time scales and then compared each others. The classic turbulence theory with the several assumptions for engine application proven to be very efficient for understanding engine turbulence in this study. It was found that the integral length scale is strongly affected and increased by tumble flow.

Bora wind characteristics for engineering applications

  • Lepri, Petra;Vecenaj, Zeljko;Kozmar, Hrvoje;Grisogono, Branko
    • Wind and Structures
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    • 제24권6호
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    • pp.579-611
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    • 2017
  • Bora is a strong, usually dry temporally and spatially transient wind that is common at the eastern Adriatic Coast and many other dynamically similar regions around the world. One of the Bora main characteristics is its gustiness, when wind velocities can reach up to five times the mean velocity. Bora often creates significant problems to traffic, structures and human life in general. In this study, Bora velocity and near-ground turbulence are studied using the results of three-level high-frequency Bora field measurements carried out on a meteorological tower near the city of Split, Croatia. These measurements are analyzed for a period from April 2010 until June 2011. This rather long period allows for making quite robust and reliable conclusions. The focus is on mean Bora velocity, turbulence intensity, Reynolds shear stress and turbulence length scale profiles, as well as on Bora velocity power spectra and thermal stratification. The results are compared with commonly used empirical laws and recommendations provided in the ESDU 85020 wind engineering standard to question its applicability to Bora. The obtained results report some interesting findings. In particular, the empirical power- and logarithmic laws proved to fit mean Bora velocity profiles well. With decreasing Bora velocity there is an increase in the power-law exponent and aerodynamic surface roughness length, and simultaneously a decrease in friction velocity. This indicates an urban-like velocity profile for smaller wind velocities and a rural-like velocity profile for larger wind velocities. Bora proved to be near-neutral thermally stratified. Turbulence intensity and lateral component of turbulence length scales agree well with ESDU 85020 for this particular terrain type. Longitudinal and vertical turbulence length scales, Reynolds shear stress and velocity power spectra differ considerably from ESDU 85020. This may have significant implications on calculations of Bora wind loads on structures.