• Particle and aerosol research
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• v.15 no.4
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• pp.139-148
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• 2019

This study was performed for the application of a high-speed centrifugal cyclone to shale gas mining process. This device uses the centrifugal force to control particles similar to typical cyclones, and the disk located inside the cyclone is forced to rotate using a motor. The pressure difference occurred during the rotating of disk. Hence, inflow rate was generated without a blower fan. In addition, flow rate increased with elevating rpm of motor. The installing the disk in multiple stages on the inner rotor increased the instantaneous disk outlet flow. Hence, the control efficiency of oil particle increased from 1.05% to 31.2%. By modifying the structure of the disk so that the air flow to the opposite direction of the cyclone, the control efficiency of oil particles increased to 81.5%. By increasing the capacity of the motor and the size of the disk, the flow rate was increased to 2.5 ㎥/min because the rpm of motor and pressure difference increased. As rpm of motor increased, the cut-off diameter (d_pc) became smaller. Unlike the Lapple's equation, d_pc was inversely proportional to the effective number of rotations (N_e). The control efficiency was maintained even if the concentration of oil particles increased, for this reason, the higher the oil concentration, the more particles were accumulated and controlled.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.9021-9025
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• 2014

Background: Breast cancer (BC) is the most common cancer among females in Turkey. Predictors affecting the breast self-examination (BSE) performance vary in developing countries. Objective: To determine the frequency of BSE performance and predictors of self-reported BSEs among women in the capital city of Turkey. Materials and Methods: This cross-sectional study was conducted on 376 Turkish women using a self-administered questionnaire covering socio-demographic variables and BSE-related features. Results: Of the participants, 78.7% (N=296) reported practicing BSE, whereas 9.5% (N=28) were implementing BSE regularly on a monthly basis, and only 5.7% (N=17) were performing BSE regularly within a week after each menstrual cycle. Multivariate logistic regression modeling revealed that BSE performance was more likely in younger age groups [20-39 years] (p=0.018, OR=3.215) and [40-49 years] (p=0.009, OR=3.162), women having a family history of breast disease (p=0.038, OR=2.028), and housewives (p=0.013, OR=0.353). Conclusions: Although it appears that the rates of BSE performers are high, the number of women conducting appropriate BSE on a regular time interval basis is lower than expected. Younger age groups, family history of breast diseases and not being employed were identified as significant predictors of practicing BSE appropriately. Older age and employment were risk factors for not performing BSE in this sample.

• Fashion & Textile Research Journal
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• v.11 no.2
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• pp.286-292
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• 2009

The purpose of this study is to analyze the pattern of the present flight suit, to select variables of human body and key dimensions for making pattern of the flight suit, and to decide the most appropriate size of human body and rate of ease for designing an overall flight suit. For analyzing the pattern of flight suit, we used "M95Special" (men ; chest circumference 92-97 cm ; height : above 177 cm), which was indicated as the standard of the Ministry of National Defense. We analyzed general appearance and the actual dimensions of the pattern of the flight suit. As a result of analyzing the pattern, flight suit was front-opened overall style which had a flat collar with rounded edges, two-pieced sleeves with lower height of the sleeve's cap, 3cm-width belt on the waist and 8 pockets. To decide the most appropriate size of human body, we selected 20 variables of human body in the 359 variables of the Size Korea by referring the previous studies. The 20 variables of human body were 9 circumferences (chest, waist, hip, neck, armscye, wrist, thigh, knee, and ankle), 9 lengths (stature, back interscye fold, waist back, crotch height, crotch, body rise, arm, outside leg and total), and 2 breadths (biacromial and chest). We drew out the size of 20 variables from the Size Korea and US Army anthropometry data and decided the most appropriate values from the drawn data for applying to the pattern of flight suit.

• Composites Research
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• v.26 no.1
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• pp.21-28
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• 2013

The ballistic limit of Carbon/Epoxy composite laminates with the finite effective area are predicted by using the quasi-static perforation test and semi-empirical formula. The perforation energy were calculated from force-displacement curve in quasi-static perforation test. Also, the actual ballistic limit and penetration energy were obtained through the high-velocity impact test. The quasi-static perforation test and high-velocity impact test were conducted for the specimens with 3 different effective areas. In the high-velocity impact test, the air gun impact tester were used, and the ballistic and residual velocity was measured. The required inputs for the semi-empirical formula were determined by the quasi-static perforation tests and high-velocity impact tests. The comparison between semi-empirical formula and high-velocity impact test results were conducted and examined. The ballistic limits predicted by semi-empirical formula were agreed well with high-velocity impact test results.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.2
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• pp.102-106
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• 2016

An experimental study on the flow characteristics under various laminar coflow diffusion flames was conducted with a particular focus on the buoyancy force exerted from gaseous hydrocarbon fuels. Methane ($CH_4$), ethylene ($C_2H_4$), and n-butane ($C_4H_{10}$) were used as the fuels. A coflow burner and the Schlieren imaging technique were used to observe the flow field of each fuel near the nozzle exit as well as the flow characteristics in the flames. The results show that a vortex with a density heavier than air appeared in n-butane near the nozzle exit with a strong negative buoyancy on the fuel steam. As the Reynolds number increased through the control of the fuel velocity of the n-butane flame, the vortices were greater and the vortex tips were moved up from the nozzle exit. In addition, the heated nozzle affected the flow fields of the fuel steam near the nozzle exit.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.9
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• pp.1077-1082
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• 2013

To improve cycling performance, the power output of the rider and the sources of resistance (e.g., air resistance, frame stiffness, and cycle mass) must be considered. From a mechanical viewpoint, we consider how the bike frame performance can be increased while decreasing the resistance. First, to improve the competitive ability of a racing track cycle, we should consider the stiffness of the bike frame including the pedal loading and aerodynamic effects when riding. Therefore, we obtained the cross-sectional area of each part of the bike frame and then aimed to minimize the drag force through an aerodynamic parametric study. In addition, the frame should remain safe under the loading applied by the rider. Under the guidelines of the UCI (union Cycliste Internationale) regulations, the bike frame has been evaluated under the proposed loading condition, and we developed a racing track cycle for elite cyclists.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.10
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• pp.857-864
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• 2016

Many plane, UAV and drone fly in the sky as development of aviation industry. Plane and UAV fly and drone's propellers rotate so fast. Impact between flying objects which have high velocity threats passengers. Also the impact damages people, building and various property. Plane's operating speed is near sound velocity(340m/s), and propeller's rotating speed is less than that. Until now, impact experiment uses gas gun to get speed and the gun needs large space to entirely air expansion. Electromagnetic launcher, especially railgun, needs smaller space than gas gun to get enough speed about 500m/s. This paper explains electromagnetic launcher's operating principle, shows making electromagnetic launcher design guide line and suggests that it is a better apparatus to get low-high velocity.

• Journal of Distribution Science
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• v.17 no.5
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• pp.103-111
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• 2019

Purpose - This paper aims to examine a spirituality's impact on the posttraumatic interpersonal relationships of family violence with a structural equation model(SEM). This article starts with the research idea that family violence experience bring about negative emotion in terms of interpersonal relationship leading to the distribution of negative affect in social relationship. The research question of this study pinpoints on how family violence experience affects interpersonal relationship problems and how spirituality affects interpersonal relations problems. Based on the idea, we attempts to deal with spirituality's impact as a driving factor of transforming the distribution of negative affect. Research design, data, and methodology - The structural equation modelling(SEM) is employed as a analysis method of this study. SEM provides a chiefly cross-sectional statistical modelling method, and moreover it allows multiple variables to be associated with a latent variable in this analysis. 300 samples from Seoul, Gyeonggy and Gangwon are selected in the survey. We chose available 271 among them. Results - The results verify that trauma have placed an negative impact on personal relations. The study results also shows that the more serious get the degree of family violence trauma, the worse become interpersonal relationship problems. What is more interesting is that the degree of trauma's impact on interpersonal relation problems in male is higher than that of trauma's impact in female. It is mainly attributed to the fact that women are superior to men in terms of empathy ability and interpersonal relationship orientation. It can be noted that the well-managed spirituality will be able to make a great contribution towards reducing the degree of trauma caused by interpersonal relationships. Conclusions - The study results demonstrates that family violence have negative impacts on spirituality, while spirituality have an positive impacts on reduction the problems of interpersonal relationship. It has been found out that family violence trauma may cause negative affectivity in personal relations, which can distribute negative impacts regarding interpersonal relationship in society. This study also supports that spirituality will be able to function well as a helper, which may reduce the distribution of negative affect in society.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.11
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• pp.761-767
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• 2019

In the present study, analyses of initial behavior of an air-launched projectile for varying initial conditions are performed by coupling computational fluid dynamics and 6 degrees of freedom calculations. Accuracy of the present numerical methods is validated by comparing the present result with the measured data. Launching safety analyses are carried out for various ejecting conditions by considering weight of the projectile and magnitude of front and rear ejector forces as the major parameters of initial behavior of the projectile. A response surface of the projectile launching safety is obtained in the range of the major parameters. In all the conditions of zero rear ejector force, unsafe launching behavior is observed. As the weight of the projectile decreases, the initial launching behavior becomes more unsafe.

• Journal of the military operations research society of Korea
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• v.34 no.2
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• pp.79-101
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• 2008

This study is for improvement of repair part demand forecasting method of Republic of Korea Air Force aircraft. Recently, demand prediction methods are Weighted moving average, Linear moving average, Trend analysis, Simple exponential smoothing, Linear exponential smoothing. But these use fixed weight and moving average range. Also, NORS(Not Operationally Ready upply) is increasing. Recommended method of Box-Jenkins' ARIMA can solve problems of these method and improve estimate accuracy. To compare recent prediction method and ARIMA that use mean squared error(MSE) is reacted sensitively in change of error. ARIMA has high accuracy than existing forecasting method. If apply this method of study in other several Items, can prove demand forecast Capability.