• Title/Summary/Keyword: natural length

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Study on Vibration Characteristics in terms of Airfoil Cross-Sectional Shape by Using Co-rotational Plane Beam-Transient analysis (Co-rotational Plane beam-Transient analysis를 이용한 에어포일 단면 형상 변화에 따른 진동특성 연구)

  • Kim, Se-Ill;Kim, Yong-Se;Park, Chul-Woo;Shin, SangJoon
    • Proceeding of EDISON Challenge
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    • 2016.03a
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    • pp.203-208
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    • 2016
  • In this paper, vibration characteristics in terms of the airfoil cross-sectional shape was examined by using the EDISON co-rotational plane beam-transient analysis. Assuming aircraft wing as a cantilevered beam with a constant cross-sectional shape, natural frequencies of each airfoil shape was compared while varying airfoil maximum thickness and maximum camber length, using Fast Fourier Transformation(FFT). When the airfoil maximum thickness was varied, natural frequency showed peak value at 18% chord, and decreased afterwards. When the airfoil maximum camber length was varied, natural frequency either increased or decreased at 6% chord, while at 8% the natural frequency showed its maximum. Applying such trends to B-737 wing airfoil, an improved B-737_mod airfoil shape was obtained with regard to the vibration characteristics.

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Morphological Characterization of small, dumpy, and long Phenotypes in Caenorhabditis elegans

  • Cho, Joshua Young;Choi, Tae-Woo;Kim, Seung Hyun;Ahnn, Joohong;Lee, Sun-Kyung
    • Molecules and Cells
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    • v.44 no.3
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    • pp.160-167
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    • 2021
  • The determinant factors of an organism's size during animal development have been explored from various angles but remain partially understood. In Caenorhabditis elegans, many genes affecting cuticle structure, cell growth, and proliferation have been identified to regulate the worm's overall morphology, including body size. While various mutations in those genes directly result in changes in the morphological phenotypes, there is still a need for established, clear, and distinct standards to determine the apparent abnormality in a worm's size and shape. In this study, we measured the body length, body width, terminal bulb length, and head size of mutant worms with reported Dumpy (Dpy), Small (Sma) or Long (Lon) phenotypes by plotting and comparing their respective ratios of various parameters. These results show that the Sma phenotypes are proportionally smaller overall with mild stoutness, and Dpy phenotypes are significantly stouter and have disproportionally small head size. This study provides a standard platform for determining morphological phenotypes designating and annotating mutants that exhibit body shape variations, defining the morphological phenotype of previously unexamined mutants.

Influence of Cu(II) on the Growth of Korean Tadpole, Rana nigromaculata (銅이온이 참개구리 幼生의 成長에 미치는 影響)

  • Park, Sang Ock;Sang Gi Kim;Soo Yeul Cho
    • The Korean Journal of Ecology
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    • v.7 no.4
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    • pp.232-238
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    • 1984
  • The author hatched the eggs of Korean frog, Rana nigromaculata in natural water, and reared the tadpoles in natural water as control group and in seven copper ion groups contaminated by 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, and 1.0 ppm of copper ion. The influences of copper ion on the growth of the tadpoles were analyzed, and the results were summarized as follows: 1) The copper ion inhibited the growth of the tadpole. 2) The tadpoles were not survived for 20 days in the copper ion of 0.4~0.5ppm, and in the 0.7ppm, the tadpoles were not survived for 1 day after hatch. 3) The critical lethal concentration of Korean tadpole is regarded as 0.6ppm of copper ion. 4) The growth of head with and body length show a convexin increase pattern. 5) In the growth quantity of head width and body length, that of natural water shows the most rapid increase pattern, and that of the copper ion groups 0.1, 0.2, and 0.3ppm follows in that order. 6) The coefficient of relative growth($\alpha$) of control group is the greatest value, and that of the copper ion groups of 0.1, 0.2, and 0.3ppm follows in that order. The natural water shows the positive allometry, the contaminated groups shows the negative allometry in the relative growth of the contaminated groups to the natural water. 7) Body length shows positive allometry in the relative growth to head width.

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Residual Stress Measurement of Micro Gold Electroplated Structure

  • Baek, Chang-Wook;Kim, Yong-Kweon;Cho, Chul-Ho;Yoomin Ahn
    • International Journal of Precision Engineering and Manufacturing
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    • v.3 no.2
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    • pp.72-77
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    • 2002
  • In this paper, a simple method to measure the residual stress in microstructure is presented. In order to find the residual stress in micro-machined beam, the first natural frequency of the beam that has the residual stress inside is analyzed using Rayleigh's energy method. Micro gold electroplated structure is fabricated by surface micro-machining process including electroplating. The made structure is an approximate shape of clamped-clamped beam and its 1 st natural frequency is measured by resonance method. For the better estimation of the residual stress, an equivalent length of micro-fabricated beam to ideal beam is calculated by FEM. The residual stress was estimated from the equivalent length and the measured natural frequency. It was found that a tensile stress was residue in the micro beam structure.

Residual Stress Measurement of Micro Gold Electroplated Structure (마이크로 금 전해 도금 구조물의 잔류응력 측정)

  • Baek, Chang-Wook;Ahn, Yoo-Min
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.12
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    • pp.195-200
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    • 2000
  • In order to find a residual stress in the micro-machined beam, first natural frequency of the beam that has the residual stress inside is analyzed using the Rayleigh's energy method. Micro gold electroplated structure is fabricated by surface micro-machining process. The made structure is clamped-clamped beam and its 1st natural frequency is measured by resonance method. For the better estimation of the residual stress, an equivalent length of micro-machined beam to ideal beam is calculated by FEM. The residual stress is estimated from the equivalent length and the measured natural frequency.

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An Anomalous Bifurcation in Natural Convection between Two Horizontal Plates with Periodic Temperatures (주기적인 온도를 갖는 두 수평 평판 사이에서의 자연 대류에서의 이례적인 분기 현상)

  • Yoo Joo-Sik;Kim Yong-Jin
    • Journal of computational fluids engineering
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    • v.9 no.4
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    • pp.1-6
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    • 2004
  • This study investigates the transition of flows in a natural convection problem with periodic wall temperatures of the form, T/sub L/=T₁+δ Tsinκχ and T/sub L/=T₂+δ Tsinκχ .The fluid considered is air with P/sub γ/=0.7. In the conduction-dominated regime with a small Rayleigh number, two large cells are formed over one wave length, for all wave numbers. When k≤1.8, the flow becomes unstable with increase of the Rayleigh number, and multicellular convection occurs above a critical Rayleigh number. The flow patterns are classified by the number of eddies over one wave length, and several kinds of transition phenomena, such as 2→3→4, 4→3→2, and 2→4 eddy flow, occur with increase( or decrease) of the Rayleigh number. Dual solutions are found above a critical Rayleigh number, and an anomalous bifurcation is observed.

Numerical investigation of steady state characteristics and stability of supercritical water natural circulation loop of a heater and cooler arrangements

  • Rai, Santosh Kumar;Kumar, Pardeep;Panwar, Vinay
    • Nuclear Engineering and Technology
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    • v.53 no.11
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    • pp.3597-3611
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    • 2021
  • The present paper studies the thermal-hydraulic behaviour of the rectangular supercritical natural circulation loop (SCNCL) using numerical model of one dimensional. Then the results of this model is confirmed with experimental and benchmark results. Variations with several geometric parameters like loop diameter, riser length, and heater length and operating conditions like heater inlet enthalpy, pressure, friction factor, and inlet and exit loss coefficient on steady-state performance are investigated for various orientations like HHHC, HHVC, VHVC and VHHC of the heater and cooler. The chances of existing static instability (Ledinegg excursion) has been investigated, which reveals that it can arise only in a low inlet enthalpy condition, far from the suggested various orientations of heater and cooler.

Embryonic Development and Early Life History of the Endangered Species Microphysogobio koreensis (Pisces: Cyprinidae) (멸종위기종 모래주사 Microphysogobio koreensis의 난발생 및 초기생활사)

  • Kim, Chi-Hong;Yoon, Seung-Woon;Kim, Jae-Goo;Kim, Hyun-Tae;Park, Jong-Sung;Park, Jong-Young
    • Korean Journal of Ichthyology
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    • v.24 no.3
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    • pp.160-166
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    • 2012
  • Egg development and early life history of the endangered Korean freshwater fish, Microphysogobio koreensis, was investigated to get a basic information for establishing its conservation strategy. The matured adult fishes were sampled at Imsil-gun, Jeollabuk-do, Korea in May 1 2012 and artificially fertilized. The fertilized eggs were spherical, separated demersal and $1.8{\pm}0.14mm$ in diameter. The hatching of the embryo began at about 29 hours after fertilization under water temperature of $23^{\circ}C$. The newly hatched pre-larvae were average $2.2{\pm}0.48mm$ in total length. At 4 days after hatching, the post-larvae were $3.6{\pm}0.55mm$ in total length and york sac was completely absorbed. At 20 days after hatching, their fin rays were formed and finally the larvae entered juvenile stage and grew up to $6.5{\pm}0.77mm$ in total length. At 60 days after hatching, the total length reached $24.4{\pm}1.71mm$, and the band patterns of he head and lateral side were similar to adult fish. Based on this study, the fertilized eggs of M. koreensis hatched more quickly and the pre-larvae length was also smaller, compared with related species.

Growth curve estimates for wither height, hip height, and body length of Hanwoo steers (Bos taurus coreanae)

  • Park, Hu-Rak;Eum, Seung-Hoon;Roh, Seung-Hee;Sun, Du-Won;Seo, Jakyeom;Cho, Seong-Keun;Lee, Jung-Gyu;Kim, Byeong-Woo
    • Korean Journal of Agricultural Science
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    • v.44 no.3
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    • pp.384-391
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    • 2017
  • Growth curves in Hanwoo steers were estimated by Gompertz, Von Bertalanffy, Logistic, and Brody nonlinear models using growth data collected by the Hanwoo Improvement Center from a total of 6,973 Hanwoo (Bos taurus coreanae) steers 6 to 24 months old that were born between 1996 and 2015. The data included three parameters: A, mature size of body measurement; b, growth ratio; and, k, intrinsic growth rate. Nonlinear regression equations for wither height according to Gompertz, Von Bertalanffy, Logistic, and Brody models were $Y_t=144.7e^{-0.5869e^{-0.00301t}}$, $Y_t=145.3(1-0.1816e^{-0.00284t})^3$, $Y_t=143.1(1+0.7356e^{-0.00352t})^{-1}$, and $Y_t=146.8(1+0.4700e^{-0.00249t})^1$, respectively, while those for hip height were $Y_t=144.5e^{-0.5549e^{-0.00312t}}$, $Y_t=145.0(1-0.1724e^{-0.00295t})^3$, $Y_t=143.1(1+0.6863e^{-0.00360t})^{-1}$, and $Y_t=146.2(1+0.4501e^{-0.00263t})^1$, respectively. Equations for body length $Y_t=174.1e^{-0.8342e^{-0.00289t}}$, $Y_t=175.8(1-0.2500e^{-0.00265t})^3$, $Y_t=170.0(1+1.1548e^{-0.00363t})^{-1}$, and $Y_t=180.3(1+0.6077e^{-0.00215t})^1$, respectively, for the same models. Among the four models, the Brody model resulted in the lowest mean square error, with mean square errors of 31.79, 30.57, and 42.13, respectively, for wither height, hip height, and body length. Also, an estimated birth wither height, birth hip height, and birth body length (77.98, 80.57, and 70.97 cm, respectively) were lower in the Brody model than in other models. An inflection point was not observed during the growth phase of Hanwoo steer according to the growth curves calculated using Gompertz, Von Bertalanffy, and Logistic models. Based on the results, we concluded that the regression equation using the Brody model was the most appropriate among the four growth models. To obtain more accurate parameters, however, using data from a wider production period (from birth to shipping) would be required, and the development of a suitable model for body conformation traits would be needed.

The Development of Leaves in Amaranthus retroflexus and Chenopodium album Represented by the Plastochron(I. The Derivation of the Plastochron Index) (Plastochron 에 의한 Amaranthus retroflexus 와 Chenopodium album 의 잎의 성장 해석 1. Plastochron Index 의 유도)

  • Park, Bong-Kyu;Joung-Hee Kim
    • The Korean Journal of Ecology
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    • v.8 no.1
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    • pp.1-5
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    • 1985
  • The plastochron index (PI) provides possibility on studies of the effects of various environmental factors on morphological and physiological development of plants. The PI of Erickson and Michemlini(1957) could be used merely when leaf n is longer an leaf n+1 is smaller than the references length at any time. If both the lengths of leaf n and n+1 are smaller or longer than the reference length, it could not estimated. In this study, the PI of Erickson and Michelini was complemented and the linear patterns according to leaf arrangement was represented, PI is n-(lnLR-lnLn)/(lnLn-lnLn+1). And when both the lengths of leaf n and n+1 are longer than the length of reference, PI is n+1+(ln Ln+1-lnLR)/(lnLn-lnLn+1). The linear model of PI is changed by the various environmental factors and the linear patterns are different according to leaf arrangement. According to leaf arrangement, the equation of the general regression lines is Yin-(i-j)=a-(n-1)(q1+...+qi-1)-(q1+...+qj-1)+rt+$\varepsilon$. Where Y:the logarithmic of the leaf length in question, i:leaf number hang on the one node, n:the number counting from base, q:spacing on the Y-axis, j:0, 1, 2, ..., r:slope, t:time, $\varepsilon$:error.

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