• Water Engineering Research
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• v.2 no.4
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• pp.243-259
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• 2001

Local phenomena around bridge piers and abutments are generally considered to be similar, nevertheless the presence of the incoming boundary layer on the side wall in the abutment case generates extra pressure gradients and consequently a more complex vortex pattern. In the literature, experimental data for bridge abutments are relatively scarce; in particular almost no data are available for the time evolution of the scour. In this work we present the results of several long duration (3 days longrightarrow5weeks) clear water scour laboratory tests around bridge abutments; the time evolution of the erosion process is analysed with respect to local and global characteristic values (maxima, volume, hole shape). In particular we analyse the effect of the constriction ratio b/B between the transversal obstacle dimension and the flume width: in many practical situations abutments (or piers) obstruct a significant portion of the channel, so that the average acceleration due to constriction is expected to increase the scour effects of the local acceleration around the obstacle. Measured values for maximum scour are poorly predicted by literature formulas. Scour depths are positively correlated with the constriction ratio, but increases are smaller than expected from literature indications. Experimental results show that models for bridge piers cannot be directly applied to abutments; in particular, time scales for the latter are significantly larger than for piers.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.5
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• pp.87-96
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• 2005

In this paper, a mesh simplification algorithm using face constriction is proposed which considers the conservation of the volume of a 3D model. The face constriction method replaces three vertices of the candidate triangle with a new vertex, removing four faces at once. We propose a modified method, compensating an existing method, of considering curvature in the decision of the removing order of triangles. We also propose a method of determining a new vertex replacing the candidate triangle, which reflects curvature difference of the three surrounding areas of the three vertices of the triangle, while conserving the volume. It is shown by simulation that the proposed method conserves the volume and shows good constriction performance comparable to the other methods.

• Restorative Dentistry and Endodontics
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• v.47 no.2
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• pp.19.1-19.15
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• 2022

Objectives: The aim of this study was to evaluate and compare the apical constriction (AC) and apical canal morphology of maxillary first and second molars, using micro-computed tomography (micro-CT). Materials and Methods: The anatomical features of 313 root canals from 41 maxillary first molars and 57 maxillary second molars of patients with known age and sex were evaluated using micro-CT, with a resolution of 26.7 ㎛. The factors evaluated were the presence or absence of AC, the morphotypes, bucco-lingual dimension, mesio-distal dimension, and the profile (shape) of AC and the apical root canal. The apical root canal dimensions, location of the apical foramen (AF), AC to AF distance, and presence of accessory canals in the apical 5 mm were also assessed. Descriptive and analytical statistics were used for data evaluation. Results: AC was present in all 313 root canals. Patients' age and sex did not significantly impact either AC or the apical canal dimensions. The most common AC morphotype detected was the traditional (single) constriction (52%), followed by the parallel (29%) morphotype. The mean AC dimensions in maxillary first molars were not significantly different from those in maxillary second molars. Sixty percent of AF were located within 0.5 mm from the anatomic apex. Conclusions: The most common morphotype of AC detected was the traditional constriction. Neither patients' age nor sex had a significant impact on the dimensions of the AC or the apical root canal. The majority of AF (60%) were located within 0.5 mm from the anatomic apex.

• BMB Reports
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• v.50 no.12
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• pp.597-598
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• 2017

Mitochondria have evolutionarily, functionally and structurally distinct outer- (OMM) and inner-membranes (IMM). Thus, mitochondrial morphology is controlled by independent but coordinated activity of fission and fusion of the OMM and IMM. Constriction and division of the OMM are mediated by endocytosis-like machineries, which include dynamin-related protein 1 with additional cytosolic vesicle scissoring machineries such as actin filament and Dynamin 2. However, structural alteration of the IMM during mitochondrial division has been poorly understood. Recently, we found that the IMM and the inner compartments undergo transient and reversible constriction prior to the OMM division, which we termed CoMIC, ${\underline{C}}onstriction$ ${\underline{o}}f$ ${\underline{M}}itochondrial$ ${\underline{I}}nner$ ${\underline{C}}ompartment$. In this short review, we further discuss the evolutionary perspective and the regulatory mechanism of CoMIC during mitochondrial division.

• Journal of Plant Biology
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• v.14 no.4
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• pp.14-18
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• 1971

Lilium Miquelianum Makino is a species which originated in Korea. The Karyotype of the species was examined in materials collected at Mts. Kaya, Kasan, Chejung, and Kaji. The results are as follows: 1) The somatic chromosome number was found to be 2n=24. 2) The karyotype is described as: K=2Am＋2Bkm＋2Csst＋2Dsst＋2Ests＋2Fst＋2Gst＋2Hst＋2Ist＋2Jsst＋2Kst＋2Lst m: metacentric, sm: submetacentric st: subtelocentric, s: secondary constriction 3) A single subcentric supernumerary B-chromosome was found in some bulbs from Mt. Kasan. 4) The shape of the supernumerary B-chromosome was similar to that of the E chromosome which had separated at its secondary constriction and lost its lower chromosome fragment. 5) From three to eight nucleio of varying sizes were found in the telophase or interphase nucleus of root tip cells. The maximum number of eight nucleoli corresponds to the number of chromosomes that have a secondary constriction.

• Water for future
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• v.18 no.4
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• pp.361-367
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• 1985

The variation of water surface profile due to the constriction of flow section in open channel was analysed by numerical scheme. Findings are that the variations of water surface are mainly dependent on the constriction ratio and Froude number of uniform flow, and the magnitudes of backwater obtained from the flow profiles agrees fairly well with the experiments by Skogerboe. This implies that the backwater can be predicted by numerical technique.

• Journal of the Korean Ceramic Society
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• v.53 no.2
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• pp.150-161
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• 2016

The conventional brick-layer model is not satisfactory either in theory or in practice for the description of dispersive responses of polycrystalline solid electrolytes with current-constriction effects at the grain boundaries. Parallel networks of complex dielectric functions have been shown to successfully describe the AC responses of polycrystalline sodium conductors over a wide temperature and frequency range using only around ten model parameters of well-defined physical significance. The approach can be generally applied to many solid electrolyte systems. The present work illustrates the approach by simulation. Problems of bricklayer model analysis are demonstrated by fitting analysis of the simulated data under experimental conditions.

• KCID journal
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• v.3 no.1
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• pp.53-63
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• 1996

The hydraulic characteristics in constriction openings are analysed numerically by using Galerkin type finite element model of which the governing equation comprises the depth averaged continuous equation and the two-dimensional Navier-Stokes equation. Fo

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.4 no.2
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• pp.115-118
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• 1975

The constriction thermal resistance due to the floor supports in the Ondol floor heating system was investigated. The resistance has significant influence on the uniformity of floor surface temperature and heat flux through the floor. The heat flux decreased as much as $30\%$ for the geometry of the same channel and support areas.

• 전기의세계
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• v.22 no.2
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• pp.57-69
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• 1973

The aim of this study was to investigate the behaviors of plasma jet under coaxial magnetic field in paralled with it for controlling optical characteristics and input power of plasma jet without impurity and instability of arc plasma column. Because the discharge characteristics of plasma jet were so distinctively different according to the existence or non-existence of magnetic field, the input power, luminous intensity of plasma jet and thermal efficiency were comparatively studied in respect of such variables as arc current, gap of electrode, quantity of argon flow, magnetic flux density, diameter and length of nozzle, with the use of several materials which were different in diameter and length of nozzel. The results were as follows; 1) The voltage tends to show a drooping characteristic at law current and then rises gradually. The luminous intensity of plasma jet increases exponentially with arc current. 2) Arc voltage increases and luminous intensity tends to decrease gradually as gap of electrode increases. 3) Arc voltage and luminous intensity tends to decrease gradually as gap of electrode increases. 3) Arc voltage and luminous intensity increase in accordance with the quantity of argon flow. 4) At first step, arc voltage increases to maximum value with the growth of flux density and then tends to show a gradual decrease. Luminous intensity decreases with the growth flux density. 5) Arc voltage decreases as the constriction length of nozzle increases, maximum decrease is shown at the constriction length of 20(mm) and it increases beyond that value. The luminous intensity decreases as the constriction length grows. 6) Arc voltage and luminous in tensity increase with the growth of diameters of nozzle. 7) Thermal efficiency has values between 50% and 75%, being influenced by arc current, the quantity of argon flow, flux density, the length of electrode gap and the constriction length of nozzle.