• Journal of Korean Society for Quality Management
• /
• v.39 no.3
• /
• pp.391-399
• /
• 2011

Our study was carried out to analyze the variation factors of severity-adjusted length of stay(LOS) in coronary artery bypass graft(CABG). The subjects were 932 CABG inpatients of the Korean National Hospital Discharge In-depth Injury Survey from 2004 through 2008. The data were analyzed using $x^2$ test and the severity-adjusted model was developed using data mining technique. The results of the study were as follows: male(71.1%), older than 61 years of age(61.6%), more than 500 beds(92.8%) and admitting via ambulatory care(70.0%) appeared to have higher rate than otherwise. In-hospital mortality of CABG inpatients was 2.8%. In addition, 46.4% of the patients received their care in other residence. The angina pectoris(45.6%) was found to be the highest in principle diagnosis, followed by chronic ischemic heart disease(36.9%) and acute myocardial infarction(12.0%). We developed severity-adjusted LOS model using the variables such as gender, age and comorbidity. Comparison of adjusted values in predicted LOS revealed that there were significant variations in LOS by location of hospital, bed size, and whether patients received the care in their residences. The variations of LOS can be explained as the indirect indicator for quality variation of medical process. It is suggested that the severity-adjusted LOS model developed in this study should be utilized as a useful method for benchmarking in hospital and it is necessary that national standard clinical practice guideline should be developed.

• Journal of Hydrogen and New Energy
• /
• v.32 no.1
• /
• pp.63-67
• /
• 2021

Accurate measurements of the heat transfer coefficients of concentric annular space for the test section is important to measure the tube-side heat transfer coefficients of working fluids. This paper presents the annular side heat transfer coefficients of concentric annuli with variation of tube diameter ratios using Wilson plot method. The test facility has a straight, horizontal test section with an active length of 3.0 m. Inner/outer diameters of test tubes are 7.0/7.5 and 8.0/8.56 mm, respectively. An outer diameter of annulus side is 16.0 mm. The test results show that convective heat transfer coefficients in annuli increase with annular diameter ratio. The correlations for convective heat transfer coefficients in annuli are also developed.

• International Journal of Highway Engineering
• /
• v.3 no.1 s.7
• /
• pp.185-197
• /
• 2001

This paper dealt with modification of effective crack length model (ECM) by adding Poisson's ratio term to evaluate fracture toughness of asphalt concrete which varies its material property by temperature. The original ECM model was developed for solid materials, such as cement concrete, and Poisson's ratio of materials was not considered. However, since asphalt concrete is sensitive to temperature variation and changes its Poisson's ratio by temperature, it should be taken into consideration to know exact fracture property under various temperatures. Four binders, including 3 polymer-modified asphalt (PMA) binders, were used to make a dense-grade asphalt mixture and 3-point bending test was peformed on notched beam at low temperatures, from -5oC to 35oC. Elastic modulus, flexural strength and fracture toughness were obtained from the test. The results showed that, since Poisson's ratio was considered, the more accurate test values could be obtained using modified ECM equation than original ECM. PMA mixture showed higher stiffness and fracture toughness than normal asphalt mixture under very low temperatures.

• Journal of Ocean Engineering and Technology
• /
• v.13 no.2 s.32
• /
• pp.51-57
• /
• 1999

In this study, one side fillet welded T-joint, used in box type girder and other welding structure, was investigated by stress analysis and bending fatigue test without edge preparation, with variation of joint shape. The purpose of this study is to give the welding condiltion and design standard on manufacturing one side fillet welded T-joint. As a result, the following conclusions were obtained. 1) In one side fillet welded T-joint, the larger the leg length and the penetration depth, the greater the bending fatigue strength because reduction of stress and strain on toe and root. The increase of the longitudinal leg length rather than vertical leg length contributed to the increase in bending fatigue strength. 2) In one side fillet welded T-joint without edge preparation, both general manual welding and general automatic welding were carried out with same condition. In this case, automatic welding showed deeper penetration and more increased longitudinal leg length than manual welding, so that automatic welding offers greater bending fatigue strength. 3) For one side fillet welded T-joint without edge preparation with automatic welding, the ratio(h/t) of the leg length(h) and the main plate thickness(t) in which toe crake can occur was 1.0 over.

• Korean journal of applied entomology
• /
• v.37 no.1
• /
• pp.23-30
• /
• 1998

Restriction fragment length polymorphism (RFLP) of a DNA has been a useful tool for analyzing genetic variation. This research was performed to establish an RFLP analytic method on the mitochondrial DNA (mtDNA) of the beet armyworm, Spodoptera exigua (Hiibner). To do this, total size of the mtDNA was measured and polymerase chain reaction (PCR) primers were selected. Its mitochondrial genome size was ca. 16kb. From a serial PCR test of 29 primers refered to the compilation of Simon et al. (1994), 22 primers were selected to amplify its mtDNA fragments. These primers resulted in short (300-700 bp) or long (1000-2000 bp) DNA products which represented a total or partial sequence of each of CO-I, CO-11, Cyt-B, ND-1, 12s rRNA, 16s rRNA, and some tRNAs. PCR-RFLP was performed in some variable mtDNA regions with 8 kinds of 4bp recognizing restriction enzymes. Different populations from Andong, Kyungsan, and Sunchun did not show any restriction site polymorphisms but had some length variation in certain regions of mtDNA.

• Journal of Advanced Marine Engineering and Technology
• /
• v.31 no.6
• /
• pp.672-680
• /
• 2007

Apparatus of rotating disk and cup are widely used spray paintings and industrial boilers. This study was conducted experimentally to investigate the characteristics of liquid atomization in a rotating disk atomizer by means of viscous liquid mixed water and glycerin. The Purpose of this study are to observe breakup mechanism according to the variation of supplied flow rate $0.4{\sim}30 cm^3/s$ and rotating speed $200{\sim}4000rpm$, and to investigate three kinds of breakup Pattern such as drop ligament and film formation by comparing the transition flow rate. ligament number and ligament length to those of Tanasawa and Matsumoto's empirical formula. The results are as follows ; The higher it makes use of viscous liquid. the better it get the characteristics of breakup mechanism. Also When I compared practical value with experiential value at similar test conditions. it was shown similar tendency though were a little variation.

• Journal of Fashion Business
• /
• v.19 no.2
• /
• pp.1-22
• /
• 2015

This study provides the basic data for clothing construction of teen girls by researching and analyzing the characteristics of physical changes of tween generation school girls between 8 to 14 age. Fifty eight items of direct measurements and 61 calculated-items based on the 6th Korean National Physical Standard Reports were used. Results were obtained by using ANOVA, SNK test, coefficient of variation and growth rate of age groups. Significant differences were found among all the age groups, and were in the increasing order of height > length > width > depth > circumference. The growth rate was found in the increasing order of bust depth > hip width > N.P. to B.P. > hip circumference > bust circumference and thigh circumference. There were dramatic increases in height, circumference and width during the age of 8~9 and 10~11, in length during age of 10~11, and in depth during age of 8~11. The growth of the vertical measurement items is slowing at the age of 13. The individual differences were great in the vertical measurements at the age of 8 and 9 and in the horizontal measurements, at the age of 10. The increasing growth of bust and hip than waist gave it a curved shape.

• Journal of Advanced Marine Engineering and Technology
• /
• v.31 no.5
• /
• pp.543-551
• /
• 2007

The performance characteristics of water-chilling heat pump using $CO_2$ with respect to variation of inlet temperature and mass flow rate of secondary fluid was investigated experimentally. An experimental apparatus is consisted of a compressor, a gas cooler, an expansion valve, an evaporator and a liquid receiver. All heat exchangers used in the test rig are counter-flow-type heat exchangers with concentric dual tubes, which ate made of copper. The gas cooler and the evaporator consist of 6 and 4 straight sections respectively arranged in parallel, each has 2.4 m length. The experimental results were summarized as the followings : As inlet temperature of secondary fluid in the gas cooler increases from $10^{\circ}C$ to $40^{\circ}C$, the compressor work, heating capacity and heating COP were varied to 37.8%, -13%, -35.9%, respectively. The heating capacity, compressor work, heating COP were turned into 23.3%, 6.42%, 13.1%, respectively when ass flow rate of secondary fluid in the evaporator increases from 70 g/s to 150 g/s. The above tendency is similar with performance variation with respect to temperature variation of secondary fluid in the conventional vapor compression cycle.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.18 no.1
• /
• pp.50-57
• /
• 2014

A ground hot-firing test (HFT) was conducted to take out the optimal design configurations for the thrust chamber of 70 N-class liquid rocket engine under development. Monopropellant grade (purity: ${\geq}98.5%$) hydrazine was adopted as a propellant for the HFT, and three kinds of thrust chambers having characteristic lengths ($L^*$) of 2.79, 2.95, and 3.13 m were selected for their performance evaluation. It is revealed through the test and evaluation that the increase of the $L^*$ leads to a performance degradation in the test condition specified, and pulse response performance of the development model shows superior characteristics to commercialized hydrazine thrusters.

• Journal of Korea Foresty Energy
• /
• v.25 no.2
• /
• pp.9-15
• /
• 2006

The quality of wood is largely depend on the characteristics of xylem tissue and their variation. They may include tracheid length, microfibril angle, distribution and amount of resin canal, as well as specific gravity as indicator of material properties. In this study, variation of these elements between and within 30 superior families of Pinus densifloa in progeny test forest were examined and the results are as follows; In terms of elongation ratio of tracheid length which is less than 1%, the sample tree showed a transition to matured wood after 13 years particularly in Kangwon 25, 30, 90, 56 and Chungnam 4 families. The average specific gravity were from 0.35 to 0.49, and differences between the families were significant. Number of transverse resin canal per unit area were also found to be significant between the families. The microfibril angles measured at 15th ring number ranged from 0.9 degree to 28.6 degree. More studies are necessary to tell whether these variation is inherited by genetic or individual characteristic. However it would be desirable that these elements be considered as key elements in the early stage of selection process of superior tree to ensure good quality of wood production in future.