• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.646-651
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• 2017

Size and shape of carbon nanotube (CNT) agglomerates in the dilute phase of a bubbling fluidized bed ($0.15m\;i.d{\times}2.6m\;high$) have been determined by the laser sheet technique. Axial solid holdup distribution of the CNT particles showed S curve with dense phase and dilute phase in bubbling fluidization regime. Heywood diameter and Feret diameter of the CNT agglomerates in the dilute phase of bubbling fluidized bed increased with increasing gas velocity. The CNT particle number in the agglomerates increased with increasing of gas velocity. Aspect ratio increased and circularity, roundness and solidity decreased with increasing of gas velocity. A possible mechanism of agglomerates formation was proposed based on the obtained information.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.9
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• pp.856-861
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• 2010

In this work, experiments on hybrid sounding rocket were conducted to investigate the aerodynamic characteristics and analyze longitudinal static stability. Tests were performed on 1/10 scale models of sounding rocket through Mach number ranging from 1.75 to 2.5 and for angle of attack from $0^{\circ}$ to $6^{\circ}$. Aerodynamic forces and moments were measured by means of a 4 component internal balance. With measured forces and moments, static stability characteristics of rocket were calculated. Tests were made for three models with different length to determine the effect of body length. The visualization of shock waves was carried out by Schlieren optical system to observe variations of shock waves with Mach number and angle of attack.

• International Journal of Reliability and Applications
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• v.7 no.1
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• pp.27-39
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• 2006

Many real world cases in material failure analysis do not follow perfectly the normal distribution. Forcing of the normality assumption may lead to inaccurate predictions and poor product quality. We examine the failure process of the internal bond (IB or tensile strength) of medium density fiberboard (MDF). We propose a forced censoring technique that closer fits the lower tails of strength distributions and better estimates extremely smaller percentiles, which may be valuable to continuous quality improvement initiatives. Further analyses are performed to build an accelerated common-shaped Weibull model for different product types using the $JMP^{(R)}$ Survival and Reliability platform. In this paper, a forced censoring technique is implemented for the first time as a software module, using $JMP^{(R)}$ Scripting Language (JSL) to expedite data processing, which is crucial for real-time manufacturing settings. Also, we use JSL to automate the task of fitting an accelerated Weibull model and testing model homogeneity in the shape parameter. Finally, a package script is written to readily provide field engineers customized reporting for model visualization, parameter estimation, and percentile forecasting. Our approach may be more accurate for product conformance evaluation, plus help reduce the cost of destructive testing and data management due to reduced frequency of testing. It may also be valuable for preventing field failure and improved product safety even when destructive testing is not reduced by yielding higher precision intervals at the same confidence level.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.187-190
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• 2006

In the present study, effects of tree-stream turbulence and surface trip wire on the flow past a sphere at $Re\;=\;0.4\;{\times}\;10^5\;{\sim}\;2.8\;{\times}\;10^5$ are investigated through wind tunnel experiments. Various types of grids are installed upstream of the sphere in order to change the tree-stream turbulence intensity. In the case of surface trip wire, 0.5mm and 2mm trip wires are attached from $20^{\circ}\;{\sim}\;90^{\circ}$ at $10^{\circ}$ interval along the streamwise direction. To investigate the flow around a sphere, drag measurement using a load cell, surface-pressure measurement, surface visualization using oil-flow pattern and near-wall velocity measurement using an I-type hot-wire probe are conducted. In the variation of free-stream turbulence, the critical Reynolds number decreases and drag crisis occurs earlier with increasing turbulence intensity. With increasing Reynolds number, the laminar separation point moves downstream, but the reattachment point after laminar separation and the main separation point are fixed, resulting in constant drag coefficient at each free-stream turbulence intensity. At the supercritical regime, as Reynolds number is further increased, the separation bubble is regressed but the reattachment and the main separation points are fixed. In the case of surface trip wire directly disturbing the boundary layer flow, the critical Reynolds number decreases further with trip wire located more downstream. However, the drag coefficient after drag crisis remains constant irrespective of the trip location.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7507-7512
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• 2015

Background: In the low incoming country Bangladesh, breast cancer is second most common neoplasm and is increasing at an alarming rate among females. Lack of awareness and illiteracy are contributory factors for late presentation and therefore mortality. Purpose: To examine associations of different factors with breast cancer mortality and to raise awareness among the women of society in Bangladesh. Materials and Methods: This descriptive case-control study was conducted on 160 participants from April 2011 till July 2014. Through a valid questionnaire covering personal and family history, data were collected by face to face interview. For analyzing correlations among factors with breast cancer data, binary logistic regression, Pearson's ${\chi}^2$-value, odd ratios and p-value tests were conducted with SPSS version 20. Results: The mean age of the patients was 43.0 ($SD={\pm}11.12$). In ascending order the leading significant factors were hormone therapy (p<0.0000, OR=4.897), abortion (p<0.0001, OR=3.452), early start menarche (p<0.0002, OR=3.500), family history (p<0.0022, OR=3.235), and late menopause (p<0.0093, OR=3.674) with both ${\chi}^2$ test and logistic regression analyses. Non-significant factors were cancer experience, fatty food habits, marital status and taking alcohol. Conclusions: Regarding the investigation of this study, significant and insignificant factor's correlation visualization with breast cancer will be helpful to increase awareness among Bangladeshi women as well as all over the world.

• Nuclear Engineering and Technology
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• v.41 no.1
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• pp.135-142
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• 2009

In this investigation, we prepared a 1 and 3-parallel serpentine single PEMFC, which has an active area of $100\;cm^2$ and a flow channel cross section of $1{\times}1mm$. Distribution and transport of water in a non-operating PEMFC were observed by varying flow types and the flow rates (250, 400, and 850 cc/min). This investigation was performed at the neutron imaging facility at the CO1d Neutron RAdiography facility (CONRAD), HMI, Germany of which the collimation ratio and neutron fluence rate are 250, $1{\times}10^{6}n/s/cm^2$, respectively. The neutron image was continuously recorded by a scintillator and lens-CCD coupled detector system every 10 seconds. It has been observed that although the distilled water was supplied into the cathode channel only, the neutron image showed a water movement from the cathode to the anode channel. The water at the cathode channel was completely discharged as soon as the pressurized air was supplied. But the water at the anode channel was not easily removed by the pressurized air except for the 3-parallel serpentine type with 850cc/min of air flow rate. Moreover, the water at the MEA wasn't removed for any of the cases.

• The Plant Pathology Journal
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• v.32 no.4
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• pp.300-310
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• 2016

Pathogen infection in plants induces complex responses ranging from gene expression to metabolic processes in infected plants. In spite of many studies on biotic stress-related changes in host plants, little is known about the metabolic and phenotypic responses of the host plants to Pseudomonas cichorii infection based on image-based analysis. To investigate alterations in tomato plants according to disease severity, we inoculated plants with different cell densities of P. cichorii using dipping and syringe infiltration methods. High-dose inocula (${\geq}10^6cfu/ml$) induced evident necrotic lesions within one day that corresponded to bacterial growth in the infected tissues. Among the chlorophyll fluorescence parameters analyzed, changes in quantum yield of PSII (${\Phi}PSII$) and non-photochemical quenching (NPQ) preceded the appearance of visible symptoms, but maximum quantum efficiency of PSII ($F_v/F_m$) was altered well after symptom development. Visible/near infrared and chlorophyll fluorescence hyperspectral images detected changes before symptom appearance at low-density inoculation. The results of this study indicate that the P. cichorii infection severity can be detected by chlorophyll fluorescence assay and hyperspectral images prior to the onset of visible symptoms, indicating the feasibility of early detection of diseases. However, to detect disease development by hyperspectral imaging, more detailed protocols and analyses are necessary. Taken together, change in chlorophyll fluorescence is a good parameter for early detection of P. cichorii infection in tomato plants. In addition, image-based visualization of infection severity before visual damage appearance will contribute to effective management of plant diseases.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.2
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• pp.173-180
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• 2001

The stink bug, Eocanthecona furcellata (Wolff.) is a natural and potential biocontrol agent of Spilarctia obliqua (Walk.). The present investigation reveals the biology, predatory efficiency and reproductive parameters of the predator which feeds on S. obliqua caterpillars in mulberry plantation. In order to find out the role of prey sine on the biology of the predators the predatory insects were separately fed with small and large caterpillars of S. obliqua. The incubation period of the eggs of E. furcellata was 8.37${\pm}$0.44 days, while the nymphal duration varied as per the prey sine. The predator when supplied with small larvae of prey, consumed 61.1 larvae and completed nymphal stage in 19.9 days; while those fed with larger prey, consumed 36.1 larvae and completed their nymphal stage in 21.55 days. The prey size also influences the reproductive parameters of the predator, The adult female predator is more voracious feeder than the adult male and consumed 41.9${\pm}$0.64 small larvae and 42.2${\pm}$0.87 large larvae during their life span. The longevity of male and female was observed as 20.7 and 29.4 days respectively. Visualization of the predator as well as the movement of the prey increases the predatory efficiency. Scanning electron microscopic studies on the feeding part explain its support in effective predation. Field observations indicated a drastic fall in the incidence of the mulberry pest, S. obliqua with the increased population E. furcellata in mulberry plantation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.4
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• pp.353-359
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• 1999

Purpose : A new method of lateral cephalometric analysis for midface, focusing on zygomatic bone, was created in this study, and measured in Korean adults. The purposes of this study are understanding about new approach for midfacial depression, especially zygomatic bone, and using to make adequate diagnosis and treatment plan. Materials and methods : In this study, esthetic Korean adults, 25 males and 25 females who were between $0^{\circ}$ and $4^{\circ}$ in ${\angle}ANB$, and between 62% and 70% in P/A facial height ratio, and had normal overbite and overjet, were used. Orbitale(Or) and Soft tissue orbitale(Or') were used for indicators of anteroposterior position of zygomatic area. And, mean value and standard deviation of linear and angular measurements, and ratio about each linear measurements, were obtained. then, standard deviation diagram - wiggle diagram - was made for visualization of results. Results : Mean values, standard deviations and ranges of 19 measurements were obtained, and among them, 5 linear measurements that had large standard deviation were excluded and the others were used for making standard deviation diagram. In standard deviation diagram, the following results were obtained. 1. If the measurements are located on more left side of mean-value-vertical -line, the potential of midfacial hypoplasia are stronger, especially zygomatic area. 2. If the measurements are located on more right side of mean-value-vertical-line, the potential of midfacial hypoplasia are decreased. Conclusion : This study presented a new method of lateral cephalometric analysis focusing on zygomatic bone in Korean adults. We expect that the results of this study can be used as parameter when clinicians make decisions about diagnosis and treatment plan for rehabilitation of esthetics and function. But, it is necessary to prove its usefulness, and to further evaluate the results.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.203-206
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• 1996

To understand the local fluid dynamics for different desists of Fontan operation, five models were made out of Pyrex glass to facilitate in-vitro study. Model I, II and III have same position of the center of the anastomosis of the IVC( inferior vena cava) with that of the SVC(superior vena cava), but Model IV and V have 10 mm offset between them. Also the anastomotic junction angles are different(Model I and $IV:90^{\circ}$, Model II and $V:70^{\circ}$, Model $III:45^{\circ}$). These models were then connected to a flow loop for flow visualization study. In Model I any dominant vortex was not seen in the central region of the juntion, but a large unstable vortex was created in the Model II and III. In Model IV and V a significant stagnation region was created in the middle of the offset region. It also showed that the flow direction from the IVC and SVC to the LPA(left pulmonary artery) and RPA(right pulmonary artery) highly depends on the offset of the junction rather than the anastomotic junction angle.