• Journal of Environmental Science International
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• v.5 no.1
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• pp.93-102
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• 1996

Hydrodynamic characteristics such as gas holdup, liquid circulation velocity and bed expansion in a hexagonal inverse fluidized bed were investigated using air-water system by changing the ratio ($A_d$/$A_r$) of cross-sectional area between the riser and the downcomer, the liquid level($H_1$/H), and the superficial gas velocity($U_g$). The gas holdup and the liquid circulation velocity were steadily increased with the superficial gas velocity increasing, but at high superficial gas velocity, some of gas bubbles were carried over to a downcomer and circulated through the column. When the superficial gas velocity was high, the $A_d$/$A_r$ ratio in the range of 1 to 2.4 did not affect the liquid circulation velocity, but the maximum bed expansion was obtained at $A_d$/$A_r$ ratio of 1.25. The liquid circulation velocity was expressed as a model equation below with variables of the cross-sectional area ratio($A_d$/$A_r$) between riser to downcomer, the liquid level($H_1$/H), the superficial gas velocity($U_g$), the sparser height[(H-$H_s$)/H], and the draft Plate level($H_b$/H). $U_{ld}$ = 11.62U_g^{0.75}$${(\frac{H_1}{H})}^{10.30}$${(\frac{A_d}{A_r})}^{-0.52}$${(\frac({H-H_s}{H})}^{0.91}$${(\frac{H_b}{H})}^{0.13}$

• Computers and Concrete
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• v.10 no.3
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• pp.259-276
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• 2012

A total of nine reinforced concrete corbels were tested, in this study. Six were externally strengthened with carbon fiber reinforced plastics (CFRP), in the horizontal direction. The cross-sectional area of CFRP and the shear span-to-effective depth ratios are the parameters considered, in this study. Test results indicate that the higher the cross-sectional area of CFRP, the higher is the shear strength of the corbels, and the lower the shear span-to-effective depth ratios, the higher is the shear strength of corbels. The shear strength predicted by the design provisions in section 11.8 of the ACI Code, the strut-and-tie model in Appendix A of the ACI Code, and the softened strut-and-tie (SST) model were compared with the test results. The comparisons show that both the strut-and-tie model in Appendix A of the ACI Code, and the SST model can accurately predict the shear strength of reinforced concrete corbels, strengthened with CFRP.

• Wind and Structures
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• v.10 no.2
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• pp.121-133
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• 2007

To gain understanding of the applicability of carbon fiber reinforced polymer (CFRP) cable in cable-supported bridges, based on the Runyang Bridge and Jinsha Bridge, a suspension bridge using CFRP cables and a cable-stayed bridge using CFRP stay cables are schemed, in which the cable's cross-sectional area is determined by the principle of equivalent axial stiffness. Numerical investigations on the dynamic behavior, aerostatic and aerodynamic stability of the two bridges are conducted by 3D nonlinear analysis, and the effect of different cable materials on the wind resistance is discussed. The results show that as CFRP cables are used in cable-supported bridges, (1) structural natural frequencies are all increased, and particularly great increase of the torsional frequency occurs for suspension bridges; (2) under the static wind action, structural deformation is increased, however its aerostatic stability is basically remained the same as that of the case with steel cables; (3) for suspension bridge, its aerodynamic stability is superior to that of the case with steel cables, but for cable-stayed bridge, it is basically the same as that of the case with steel stay cables. Therefore as far as the wind resistance is considered, the use of CFRP cables in cable-supported bridges is feasible, and the cable's cross-sectional area should be determined by the principle of equivalent axial stiffness.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.10
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• pp.11-18
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• 2018

In this study, the cross-sectional image has been acquired to evaluate the aggregate distribution affecting quality of lightweight aggregate concrete, and through the binarization method, the study is to calculate the aggregate area of upper and lower sections to develop the method to assess the aggregate distribution of concrete. The acquisition of cross-section image of concrete for the above was available from the cross-sectional photography of cleavage tension of a normal test specimen, and an easily accessible and convenient image analysis software was used for image analysis. As a result, through such image analyses, the proportion of aggregate distribution of upper and lower sections of the test specien could be calculated, and the proportion of aggregate area U/L value of the upper and lower regions of concrete cross-section was calculated, revealing that it could be used as the comprehensive index of aggregate distribution. Moreover, through such method, relatively easy image acquisition methods and analytic methods have been proposed, and this indicated that the development of modeling to assess aggregate distribution quantitatively is available. Based on these methods, it is expected that the extraction of fundamental data to reconsider the connectivity with processes in concrete will be available through quality assessment of quantitative concrete.

• Journal of Veterinary Clinics
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• v.40 no.3
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• pp.225-229
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• 2023

In three dogs showing cerebellar ataxia, the onset of clinical signs varied from a young age of five months to age 13 years. Qualitative magnetic resonance imaging (MRI) revealed various degrees of cerebellar atrophy, and a tentative diagnosis of cerebellar cortical degeneration was made. Quantitative analysis using the brainstem to the cerebellar cross-sectional area ratio (BS:CBM ratio) and T2-signal intensity histograms were obtained to perform an objective evaluation. These techniques have the advantage of being easy and fast to evaluate. These quantitative analyses revealed the severity of cerebellar cortical degeneration in the three dogs as mild, moderate, and severe. Dogs 2 and 3 were identified as abnormal on the relative cerebrospinal fluid (CSF) space using T2-signal intensity histograms but were normal on the BS:CBM ratio. This suggests that the T2-signal intensity histograms may have higher sensitivity than BS:CBM ratio.

• Journal of Veterinary Clinics
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• v.40 no.3
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• pp.182-188
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• 2023

Sarcopenia and myosteatosis can increase the risk of adverse effects in dogs and humans. However, such imaging study results for evaluating sarcopenia and myosteatosis in small dogs have not yet been available. The objective of this study was to assess age-related changes according to the breed in epaxial muscle cross-sectional area (CSA) and fat infiltration using CT to evaluate sarcopenia and age-related myosteatosis in small breed dogs. In 144 dogs (92 Maltese dogs, 27 Poodle dogs, and 25 Shih Tzu dogs), Hounsfield Unit (HU) values and CSA of left epaxial muscle were measured at the thirteenth thoracic vertebral level on non-contrast transverse CT images. Differences in HU values and CSA according to age and breed were analyzed. The geriatric group (≥12 years) had significantly lower HU values of epaxial muscle than mature adult group (2 to 6 years) of all breeds. The geriatric group had significantly lower CSA of epaxial muscle than mature adult and senior groups (7 to 11 years) of Maltese dogs. HU values of epaxial muscle were not significantly different among all age groups of all breeds. Maltese dogs had significantly lower CSA of epaxial muscle than Poodle and Shih Tzu dogs in all age groups. Results of this study showed that as age increased in small breed dogs, muscle mass and density decreased.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.1
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• pp.66-73
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• 2011

This paper deals with free vibrations of the tapered beams with the constant surface area. The surface area of the objective beams are always held constant regardless shape functions of the cross-sectional depth. The shape functions are chosen as the linear and parabolic ones. Ordinary differential equations governing free vibrations of such beams are derived and solved numerically for determining the natural frequencies. In the numerical examples, hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered. As the numerical results, the relationships between non-dimensional frequency parameters and various beam parameters such as section ratio, surface area ratio, end constraint and taper type are reported in tables and figures. Especially, section ratios of the strongest beam are calculated, under which the maximum frequencies are achieved.

• The KSFM Journal of Fluid Machinery
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• v.9 no.2 s.35
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• pp.44-49
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• 2006

In this study, the effects of volute area distribution on the performance of a centrifugal pump were numerically studied using a commercial CFD code. To reduce the shutoff head, maintaining head and efficiency at a design flow rate, the flat head-capacity characteristic curves in which the head varies only slightly with capacity from shutoff to design capacity are frequently required. In order to control the shutoff head of a pump, several volute cross-sectional area distributions were proposed as a main parameter with the same impeller geometry The calculation results show that the slope of the performance characteristic curve of the centrifugal pump can be controlled by modifying the area distribution from volute tongue to volute outlet with fixed volute outlet area and also varied volute outlet area.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.497-502
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• 2005

In this study. the effect of volute area distribution on the performance of a centrifugal pump were numerically studied using a commercial CFD code. To reduce the shutoff head, maintaining head and efficiency at a design flow rate. the flat head-capacity characteristic curves in which the head varies only slightly with capacity from shutoff to design capacity are frequently required. In order to control the shutoff head of a pump, several volute cross-sectional area distributions were proposed as a main parameter with the same impeller geometry. The calculation results show that the slope of the performance characteristic curve of the centrifugal pump can be controlled by modifying the area distribution from volute tongue to volute outlet with fixed volute outlet area and also varied volute outlet area.

• Journal of Oral Medicine and Pain
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• v.41 no.3
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• pp.85-90
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• 2016

Purpose: The aim of this study was to develop an automated software to extract tooth and pulpal area from sectional cone-beam computed tomography (CBCT) images, which can guarantee more reproducible, objective and time-saving way to measure pulp/tooth volume ratio. Methods: The software program was developed using MATLAB (MathWorks). To determine the optimal threshold for the region of interest (ROI) extraction, user interface to adjust the threshold for extraction algorithm was added. Default threshold was determined after several trials to make the outline of extracted ROI fitting to the tooth and pulpal outlines. To test the effect of starting point location selected initially in the pulpal area on the final result, pulp/tooth volume ratio was calculated 5 times with different 5 starting points. Results: Navigation interface is composed of image loading, zoom-in, zoom-out, and move tool. ROI extraction process can be shown by check in the option box. Default threshold is adjusted for the extracted tooth area to cover whole tooth including dentin, cementum, and enamel. Of course, the result can be corrected, if necessary, by the examiner as well as by changing the threshold of density of hard tissue. Extracted tooth and pulp area are reconstructed three-dimensional (3D) and pulp/tooth volume ratio is calculated by voxel counting on reconstructed model. The difference between the pulp/tooth volume ratio results from the 5 different extraction starting points was not significant. Conclusions: In further studies based on a large-scale sample, the most proper threshold to present the most significant relationship between age and pulp/tooth volume ratio and the tooth correlated with age the most will be explored. If the software can be improved to use whole CBCT data set rather than just sectional images and to detect pulp canal in the original 3D images generated by CBCT software itself, it will be more promising in practical uses.