• Journal of the korean Society of Automotive Engineers
• /
• v.15 no.2
• /
• pp.92-104
• /
• 1993

In the present study, the velocity profiles and entrance length of developing transitional pulsating flows are investigated both analytically and experimentally in the entrance region of a square duct. The systems of conservation equations for transitional pulsating flows in a square duct are solved analytically by linearizing the non-linear convective terms. Analytical solutions are obtained in the form of infinite series for velocity pofiles. The experimental study for the air flow in a square duct(40mm*40mm*4000mm) is carried out to measure velocity profiles and other parameters by using a hot-wire anemometer with a data acquisition and processing system. The distribution of velocity profiles( $u_{ps}$ / $u_{m,ta}$) in the decelerating period is higher than in the accelerating period. The distribution of the axial component of the axial component of velocity in the transitional flow is nearly uniform in the central region of the duct, and decrease rapidly near the wall. The entrance length correlation of the transitional pulsating flows in a square duct is obtained to be $L_{e}$/ $D_{h}$=0.83 $A_{1}$R $e_{ta}$ /(.omega. sup+1)$^{2}$TEX>

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.22 no.9
• /
• pp.1335-1348
• /
• 1998

Flow characteristics in transitional boundary layers on a flat plate were experimentally investigated under three different freestream conditions i. e. uniform flow with 0.1 % and 3.7% freestream turbulent intensity and cylinder-wake with 3.7% maximum turbulent intensity. Instantaneous streamwise velocities in laminar, transitional and turbulent boundary layers were measured by I-type hot-wire probe. For estimation of wall shear stresses on the flat plate, measured mean velocities near the wall were applied to the principle of Computational Preston Tube Method (CPM). Distributions of skin friction coefficients were reasonably predicted in all developed boundary layers. Intermittency profiles, which were estimated using Conditional Sampling Technique in transitional boundary layers, were also consistent with previously published data. It was predicted that the incoming turbulent intensity had more influence on transition onset point and transition process than freestream turbulent intensity existed just over the transition region. It was also confirmed that non-turbulent and turbulent profiles in transitional boundary layers could not be simply treated as Blasius and fully turbulent profiles.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.2 no.1
• /
• pp.1-10
• /
• 1990

In the present study, the entrance length, velocity profiles and waveforms of developing transitional steady flows in a square duct are investigated analytically and experimentally. The systems of conservation equations for transitional steady duct flows are solved analytically by linearizing non-linear convective terms and adoption of modified eddy viscosity from empirical correlations. Analytical solutions of velocity profiles for developing transitional steady flow were obtained in the form of infinite series. The experimental study for transitional steady flow in a square duct with $40mm{\times}40mm{\times}4000mm$($width{\times}height{\times}length$) was carried out to measure velocity profiles and other parameters by using a hot-wire anemometer with data acquisition and processing system. The entrance length of developing transitional steady flows in a square duct was $L_e{\fallingdotseq}0.02{\cdot}Re,st{\cdot}D_h$, and the overshoot was occured at about 30 times of hydraulic diameter because of the effect of external velocity of boundary layer and instantaneous acceleration.

• Journal of Welding and Joining
• /
• v.16 no.4
• /
• pp.39-46
• /
• 1998

$CO_2$ gas shielded arc welding has been characterized with its harsh arc compared to Ar-based shielding gases and with its high level of spattere specially in welding current range of 250~300 amperes. In this range of welding current, the metal transfer mode showed to be changed from short circuit to globular with the increase of welding voltage resulting in so-called the transitional mode in which both modes of transfer appeared together. To characterize the transitional mode, the short circuit events were divided into two groups, i.e. normal short circuit (N.S.C) which has short circuit time $(t_s)$ over 2msec and instantaneous short circuit (I.S.C) of $t_s$$\leq$2msec. The experimental results showed that the number of N.S.C decreased almost linearly with the increase of welding voltage and appeared to be not related with spatter generation rate. However I.S.C became to be pronounced in the transitional condition and its number reached the maximum value at around 29.0 volts. Considering the relation with the spatter generation rate, it was found that the number of I.S.C had a very strong correlation with the spatter generation rate of the transitional condition. It was further demonstrated that spatter generation rate decreased quite linearly with the decrease of I.S.C frequency. It implies that I.S.C is the most important waveform factor controlling the spatter generation of the transitional mode, i.e. in the middle range of welding current. Based on these results, It was discussed that in the transitional mode the basic concept of waveform control for suppressing spatter generation would be different from the one applied for typical short circuit transfer mode of low welding current.

• Korea journal of population studies
• /
• v.18 no.2
• /
• pp.51-69
• /
• 1995

The Swedish welfare state has been the model for others to emulate the archetypical example of state intervention. The state interventions are presented in the form of legal acts. These social welfare acts can be classified according to the demographic transition theory. According to the Bogue's theory, the demographic transition in Sweden took place in four stages : the pre-transitional stage before 1810; the early transitional stage from 1810 to 1860; the mid-transitional stage from 1860 to 1930; the late transitional stage from 1930 to now. As we look into the social welfare acts in Sweden, the relief of the poor was the major concern of the early transitional stage, the care of workers was the major concerns of the mid-transitional stage and the care of the families was the major concerns in the late transitional stage. The Korea's transition period can be devided as follows; the pre-transitional stage before 1960; the early transitional stage from 1960 to 1969; the mid-transitional stage from 1970 to 1987; and the late transitional stage from 1987 to now. In Korea, the major concern of the early transitional stage was the care of the officials and the workers; in the mid-transitional stage the care of the aged and the handicapped were the major concerns. And in the late transitional stage the expanding of the welfare clients was the major concern. If we compare the results of both countries, the relief of the poor, the care of the workers and the care of the families will be the major concerns in Korea, because the social welfare acts in Korea are extended to specific groups and not to the whole population. The acts related to these social issues have been arranged in 120 years in Sweden. But Korea had to do the same work in 27 years. So the burden of making those social acts will be four times heavier. If we want to extend the benefits of the social system to the general population, we need to look at the design and approach of the swedish model. The reason why swedish social acts constitute an international model has more to do with the uniqueness of its design and approach. First of all, it is characteristic by its universalism, secondly by its emphasis on social services and thirdly by its productivitism. Also the swedish welfare state supported by a high-tax system called the earnings-related welfare system. In order to achieve an effective welfare state, we Koreans should pay attention to the relief of the poor, the care of the worker and the families. We should also focus on a good system design and prepare appropriate budgets.

• Journal of computational fluids engineering
• /
• v.20 no.3
• /
• pp.54-61
• /
• 2015

In the present study, a flow solver using a kinetic BGK scheme was developed for the compressible Navier-Stokes equation. The kinetic BGK scheme was used to simulate flow field from the continuum up to the transitional regime, because the kinetic BGK scheme can take into account the statistical properties of the gas particles in a non-equilibrium state. Various numerical simulations were conducted by the present flow solver. The laminar flow around flat plate and the hypersonic flow around hollow cylinder of flare shape in the continuum regime were numerically simulated. The numerical results showed that the flow solver using the kinetic BGK scheme can obtain accurate and robust numerical solutions. Also, the present flow solver was applied to the hypersonic flow problems around circular cylinder in the transitional regime and the results were validated against available numerical results of other researchers. It was found that the kinetic BGK scheme can similarly predict a tendency of the flow variables in the transitional regime.

• Journal of Forest and Environmental Science
• /
• v.29 no.3
• /
• pp.194-199
• /
• 2013

The aim of the present study was to assess the effect of transitional boundary on community composition and soil carbon stock. Five vegetation types were recognized horizontally along the transitional strip based on the dominance of tree species i.e., Pure Anogeissus latifolia forest (P.AL), mixed Pinus roxburghii and Lannea coromandelica forest (M.PR&LC), pure Pinus roxburghii forest (P.PR), mixed Pinus roxburghii and Lannea coromandelica (M.PR&LC) and pure Anogeissus latifolia forest (P.AL). The results revealed that Anogeissus latifolia was reported dominant tree in the outer transitional boundaries of the forest, which reduced dominance of trees towards middle where Pinus roxburghii was found dominant. The soil carbon stock was reported higher in the Anogeissus latifolia dominant forest and reduced with the dominance of Pinus roxburghii in the middle site. Both the species are growing close to one another and competing for survival, but the aggressive nature of Anogeissus latifolia particular in this region may change new growth of Pinus roxburghii and will enhance soil carbon stock. But high anthropogenic pressure on Anogeissus latifolia tree species could be limited chance to further its flourish.

• Journal of East-West Nursing Research
• /
• v.27 no.1
• /
• pp.78-86
• /
• 2021

Purpose: The purpose of this study was to understand the correlations between transitional shock, incivility and nursing professionalism among nursing students. Methods: A total of 143 nursing students completed transitional shock, incivility and nursing professionalism, using structured questionnaires. The collected data were analyzed using the t-test, ANOVA, Pearson's correlation coefficient, and multiple regression analysis. Results: The results showed that nursing professionalism was significantly correlated with gender (β=.20, p=.001), major satisfaction (β=.44, p=.007), clinical practice satisfaction (β=.45, p<.001), transitional shock (β=-.20, p=.012), and incivility experienced (β=-.18, p=.021) among nursing students. Conclusion: It is necessary to develop a plan for reducing individual satisfaction with clinical practice and the transitional shock of nursing students. It ultimately may increase nursing students' nursing professionalism. In addition, a strategy is needed to reduce incivility among nursing students by creating positive educational environment in clinical practice through cooperation between schools and training institutions, and to strengthen desirable nursing professionalism.

• Journal of Korean Academy of Nursing
• /
• v.53 no.5
• /
• pp.556-569
• /
• 2023

Purpose: This phenomenological study tried to understand the essence of the transitional care experience of medicaid case managers and its structural meaning. In addition, it was attempted to establish a system of transitional care and seek support measures for medicaid case managers. Methods: The participants of this study were 7 medicaid case managers who had spent more than 1 year and 6 months in medicaid pilot project. Data were collected with individual in-depth interviews from June to December 2021. The data were analyzed by Giorgi's phenomenological analysis method. Results: The seven constituents derived from the results of this study were 'struggle to establish a living environment', 'dedication to supporting independent living', 'anxiety about safety', 'pressure on care responsibilities', 'distress in building the pilot project', 'pride in role', and 'expectation for improvement'. Conclusion: The study results provide a comprehensive understanding of the transition care reality for medicaid case managers. They also shed light on managers' perceptions and attitudes. These findings can serve as fundamental information for establishing support measures for medicaid case managers and transitional care systems.

• Journal of Veterinary Clinics
• /
• v.19 no.2
• /
• pp.268-271
• /
• 2002

Transitional cell carcinoma(TCC) was identified by cytological and ultrasonographic findings in an 11-year-old, intact female Yorkshire terrier with intermittent hematuria for three years. In color-doppler ultrasound images there was marked irregular wall thickness of the bladder surface and well-defined hyperechoic focal lesions within the mass. Active vascular response was observed in the surroundings of hyperechoic lesions.