• Title/Summary/Keyword: tip shape

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Estimation of the Relative Density and Internal Friction Angle for Sand using Cone-tip Resistance of the PCPT (휴대용콘의 선단저항값을 이용한 모래의 상대밀도 및 내부마찰각 추정)

  • Park, Jae-Sung;Son, Young-Hwan;Noh, Soo-Kack;Bong, Tae-Ho
    • Journal of The Korean Society of Agricultural Engineers
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    • v.54 no.4
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    • pp.137-145
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    • 2012
  • Sand is one of the essential materials used for social infrastructure construction such as embankment, landfill and backfill. It was known that mechanical properties and shear strength of sand are closely related to relative density. Therefore it is very important to determine accurate relative density. In this study, Portable Cone Penetration Tester (PCPT) was used to estimate the relative density and the internal friction angle of sand. PCPT cone-tip resistance ($q_c$) was measured changing the relative density of the two soil samples.Standard sand (JMJ) and Busan sand (BS). Also, a direct shear test was performed to investigate relationship between relative density and internal friction angle. The size and shape of soil particles were confirmed by using Scanning Electron Microscope (SEM). As a result, the log value of $q_c$ was linearly correlated with relative density and internal friction angle. In particular, the internal friction angle of BS sample was greater than that of JMJ, which was due to difference of the shape and mean size of particles. This result shows that it is important to determine the shape and size of particles as well as relative density to define mechanical property of sand. Through this study, it can be more effectively and conveniently to investigate relative density and shear strength of sand by using PCPT in situ.

A Numerical Analysis of Partial Admission Turbine's Performance for Design Parameters of 3D Supersonic Nozzle (3차원 초음속 노즐 형상 변수에 따른 부분입사형 터빈 성능 특성에 관한 수치적 연구)

  • Shin Bong-Gun;Kwak Young-Jae;Kim Kui-Soon;Kim Jin-Han
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2005.11a
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    • pp.34-39
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    • 2005
  • In this study, 3-D nozzle shape and the shape of nozzle at exit plane were adopted as design parameter of 3-D supersonic nozzle and numerical analyses for these parameters have been performed to investigate the flow and performance characteristics for design parameters of the turbine. Firstly, comparing results for nozzle shape, rectangular nozzle had less total pressure loss occurred in axial gap and more power by 1.5% than circular nozzle did. Next, comparing the results for the shape of nozzle at exit plane, it is found that the performance of partial admission turbine was largely depended upon the gap between nozzle wall at exit plane and the hub / tip of rotor blade and the length between nozzles.

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A Study on the Characteristics of Facial Shape in Adult Women by Sasang Constitution Using Hyungsang Classification (형상분류를 이용한 성인여성의 체질별 안면형태 특징에 관한 연구)

  • Jeon, Soo-Hyung;Kim, Jong-Won
    • Journal of Sasang Constitutional Medicine
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    • v.29 no.2
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    • pp.95-103
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    • 2017
  • Objectives This study was aimed to analyze characteristics of facial shapes in adult women by sasang constitution using hyungsang classification. Methods Using a digital camera, we took a picture of 1,011 women who participated in clinical study on menstrual pain and acquired their 3D facial images with a face-only scanner. They filled out SSCQ-P(sasang constitution questionnaire for patient) for the diagnosis of sasang constitution. Based on the above photographs and 3D images, one of the hyungsang medicine specialist diagnosed according to five diagnostic criteria. The sasang constitution was diagnosed by referring to questionnaires and photographs. Frequency analysis was performed using the statistical analysis system version 9.4 and chi-square test was performed for validity evaluation. Results In taeeumin, the wide face shape(n=261, 74.36%) was much more than the narrow shape(n=90, 25.64%) and the convex face profile(n=164, 85.86%) was much more than the concave profile(n=27, 14.14%). Regardless of sasang constitution, angular face shape(n=501, 50%) was the most, followed by oval shape(n=317, 31.64%). Subjects with big ears(n=291, 29.19%) were the most, while big eyes(n=104, 10.43%) were the least. Subjects with eyes and nose tip upward(n=615, 78.05%) were the most, while eyes and nose tip downward(n=22, 2.79%) were the least. Conclusions Most Korean adult women have angular face, such as square or diamond, with slanted eyes and upturned nose. Taeeumin women have wide facial shape and convex profile.

Classification of Adult Women's Fingernail Type (성인 여성의 손톱 유형 분류)

  • Kim, Ha Eun;Kim, Nam Soon;Do, Wol Hee
    • Fashion & Textile Research Journal
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    • v.22 no.4
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    • pp.504-514
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    • 2020
  • This study improves the dimensional suitability of nail tip products by reviewing the type of fingernail as seen among adult women in Korea. Subjects were 147 adult women ranging from age 20 to 40. Direct fingernails measurements were made using digital Vernier calipers and a curvature gauge. Data on various fingernail shapes were collected through indirect measurements using photography to reveal the shape characteristics of each fingernail types. In this sense, data were analyzed by statistical methods with the use of factor analysis. There were various factors considered to classify extracted fingernail types such as five factors (for the thumb), four factors (index, middle, and little fingers), and three factors (for the ring finger). The cluster analysis resulted in three types. Type 1 is a 'Square' shape characterized with wide fingernails, low height, flat, and low curvature of the cuticle line. Type 2 is 'U-round' shape characterized with narrow fingernails, high height, convex, and the highest curvature of the cuticle line. Type 3 is a 'Round' shape in which the fingernails are wide, high in height, convex, and characterized with a medium curvature of the cuticle line. The results are useful for companies that develop the free edge shape of fingernails for consumer products. The measured values of fingernail can be applied to the shape and lake setting of the nail tip product, depending on type of fingernail.

Effect of Additive Ammonium Hydroxide on ZnO Particle Properties Synthesized by Facile Glycol Process

  • Phimmavong, Kongsy;Hong, Seok-Hyoung;Song, Jeong-Hwan
    • Korean Journal of Materials Research
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    • v.31 no.9
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    • pp.481-487
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    • 2021
  • ZnO particles are successfully synthesized at 150 ℃ for 30 min using zinc acetate as the Zn source and 1,4-butanediol as solvent using a relatively facile and convenient glycol process. The effect of ammonium hydroxide amounts on the growth behavior and the morphological evolution of ZnO particles are investigated. The prepared ZnO nanoparticle with hexagonal structure exhibits a quasi-spherical shape with an average crystallite size of approximately 30 nm. It is also demonstrated that the morphology of ZnO particles can be controlled by 1,4-butanediol with an additive of ammonium hydroxide. The morphologies of ZnO particles are changed sequentially from a quasi-spherical shape to a rod-like shape and a hexagonal rod shape with a truncated pyramidal tip, exhibiting preferential growth along the [001] direction with increasing ammonium hydroxide amounts. It is demonstrated that much higher OH- amounts can produce a nano-tip shape grown along the [001] direction at the corners and center of the (001) top polar plane, and a flat hexagonal symmetry shape of the bottom polar plane on ZnO hexagonal prisms. The results indicate that the presence of NH4+ and OH- ions in the solution greatly affects the growth behaviors of ZnO particles. A sharp near-band-edge (NBE) emission peak centered at 383 nm in the UV region and a weak broad peak in the visible region between 450 nm and 700 nm are shown in the PL spectra of the ZnO synthesized using the glycol process, regardless of adding ammonium hydroxide. Although the broad peak of the deep-level-emission (DLE) increases with the addition of ammonium hydroxide, it is suggested that the prominent NBE emission peaks indicate that ZnO nanoparticles with good crystallization are obtained under these conditions.

Popping Mechanism and Shape Moulding Factor of Popcorn (튀김옥수수의 파열방향 및 튀김형태 결정요인)

  • Kim, Sun-Lim;Park, Seung-Ue;Kim, E-Hun
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.40 no.1
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    • pp.98-102
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    • 1995
  • Popped popcorn generally have a regular popping direction and typical shape. But the reason and mechanism are not clear yet. This experiment was carried out to investigate the shape moulding factor of popped popcorn. Pericarp thickness of tip-cap section of kernels is slightly thicker than that of top section and this fact provides the important information to the reason. Popping starts when the moisture pressure of heated popcorn is increased and reaches at the critical pressure. Therefore, in the same moisture pressure conditions, top sections are bursted first because their pericarp section is thinner than that of tip-cap section. At the very moment tip-cap sections pull down the top sections of peri carp as bi-metal does. So kernels which removed tip-cap section showed the irregular popping shape because they lost the tip-cap pericarp function. How-ever, kernels which removed embryo showed the typical popping shape but their popping volume was small due to emition and shortage of critical moisture pressure. But kernels which removed the whole pericarp and top pericarp were not popped at all because moisture was entirely emitting out of kernels. These results suggest that the shape moulding factor of popped popcorn is the pericarp thickness differences between the top and tip-cap section of kernels.

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