• Wind and Structures
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• v.25 no.4
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• pp.381-395
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• 2017

Nonlinear vibration and instability of cylindrical shell conveying fluid-nanoparticles mixture flow are studied in this article. The surrounding elastic medium is modeled by Pasternak foundation. Mixture rule is used for obtaining the effective viscosity and density of the fluid-nanoparticles mixture flow. The material properties of the elastic medium and cylindrical shell are assumed temperature-dependent. Employing first order shear deformation theory (FSDT), the motion equations are derived using energy method and Hamilton's principal. Differential quadrature method (DQM) is used for obtaining the frequency and critical fluid velocity. The effects of different parameters such as volume percent of nanoparticles, boundary conditions, geometrical parameters of cylindrical shell, temperature change, elastic foundation and fluid velocity are shown on the frequency and critical fluid velocity of the structure. Results show that with increasing volume percent of nanoparticles in the fluid, the frequency and critical fluid velocity will be increases.

• The Korean Journal of Physiology
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• v.29 no.1
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• pp.81-89
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• 1995

The effects of prolactin and vasopressin on the regulation of amniotic fluid (AF) volume and its $Na^{+}$ concentration $([Na^{+}])$ through the membrane surrounding the AF during increase in AF volume due to fetal urination were studied. About 70% of AF volume was replaced with normal isotonic saline solution. Isotonic saline solution (0.5 ml) containing Censored and LiCl was introduced into each amniotic sac. Vasopressin (25 ng/ml) or prolactin (1 mg/ml) of AF was then injected into experimental amniotic sac. The concentrations of Congored, $Li^{+}$, and $Na^{+}$ were measured at 30 and 60 min intervals after injection. Af samples with decreased Censored concentration ([CR]) during the period of 30 - 60 min were analyzed. The percentage change of $[Na^{+}]$ and the rate of $Li^{+}$ movement during this period were calculated, and the effects of vasopressin and prolactin on them were evaluated. Fellowing results were obtained: 1. The rate of reduction of [CR] in the AF was retarded by vasopressin or prolactin injection. 2. The rate of reduction of $[Li^{+}]$ in the AF was also retarded by vasopressin or prolactin injection. 3. The rate of reduction of $[Li^{+}]$ in the AF was less retarded by vasopressin than that of [CR]. 4. $[Na^{+}]$ changed to approach to the normal level, but this was markedly retarded by prolactin injection. 5. Direction of $Li^{+}$ movement was correlated with the change in $[Na^{+}]$ but it always moved out of the amniotic sac even when the $[Na^{+}]$ increased in vasopressin injected AF. From the above results, it is suggested that vasopressin in the AF triggers the fetus to urinate, and then the membranes surrounding the AF regulate osmolarity by efflux of $Na^{+}$. We suggest that prolactin facilitates water outflow across the amniotic membrane during increase in AF volume, in contrast to a constant volume, whereas regulation of $[Na^{+}]$ is partly restricted by prolactin.

• The Korean Journal of Physiology
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• v.3 no.1
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• pp.1-9
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• 1969

Relationships between red ceil volume $(^{51}Cr-cell)$, total blood volume (red cell volume divided by hematocrit ratio), and extracellular fluid volume (SCN distribution space) and body weight (ranging between 73 and 384 grams) or lean body mass were studied in 59 nembutalized rats. Lean body mass was determined by means of underwater weighing method on rats clipped and eviscerated. There were positive correlations between body weight or lean body mass and the absolute values (in milliliters) of body fluid volumes. Body fluid volumes expressed on the body weight or lean body mass basis, however, showed negative correlations between body weight (grams) or lean body weight (grams) with one exception. Red cell volume expressed as % lean body mass showed a positive correlation with lean body mass. The other results are summarized as follows: 1. Body density of rats was 1.0561 $(range:\;1.0123{\sim}1.0781)$ and 19.8% body weight of total body fat was obtained. The mean value of lean body mass was 80.2% body weight 2. The correlation between body weight and lean body mass was high, namely, coefficient of correlation was r=.99. 3. The correlation between the absolute value of red cell volume (ml) and body weight showed a high correlation, namely, r= 92 and between the lean body mass coefficient of correlation was r=.93. On a weight basis, red cell volume was 2.67 ml/100 gm body weight or 3.48 ml/100 gm lean body mass. The coefficient of correlation between body weight (grams) and red cell volume (% body weight) was r=-. 30. The coefficient of correlation between lean body mass (grams) and red cell volume (% lean body mass) was r=. 50. Thus, the following regression equation was obtained. Red cell volume (% lean body mass)=. 00243 Lean body mass (gm)+3. 12. 4. Total blood volume was 6.06% body weight or 7.83% lean body mass. The correlation between these blood volume values and body weight or lean body mass were negative, namely, r= -.43 and r=-.42 respectively. 5. Extracellular volume (SCN space) was 30.0% body weight or 37.2% lean body mass. These percentage values showed negative correlations between body weight or lean body mass and coefficients of correlation were r=-.40 and r=-.54 respectively. 6. The rate of increase in body weight or lean body mass is accompanied by a smaller rate of increase in blood volume and extracellular fluid volume. The rate of increase in red ceil volume paralled that of lean body mass.

• Journal of Trauma and Injury
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• v.19 no.1
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• pp.41-46
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• 2006

Purpose: Hypovolemia is not uncommon among trauma patients in the emergency department (ED). Successful resuscitation of a hypovolemic patient often requires rapid intravenous administration of massive amounts of fluid. A rapid fluid infuser is used in the ED for this purpose, there have been no studies of their clinical uses and effectiveness. We studied clinical experience with a rapid fluid infuser at an urban university hospital in Seoul, Korea. Methods: We reviewed the medical records of 38 patients admitted to the ED with a history of application of a rapid fluid infuser from January 2004 to July 2005. Adult trauma patients older than 15 years of age were included in this study. Clinical data on the patients and the volume of fluid used to achieve a stable blood pressure were extracted from their medical records. Results: The total number of adult trauma patients with a history of application of a rapid fluid infuser from January 2004 to July 2005 in the ED was 16. The mean systolic blood pressure for deciding to apply the rapid fluid infuser was $74.9{\pm}12.7mmHg$. The mean time and volume used to achieve a stable blood pressure were 40.4 min and$2947.3{\pm}1339.2ml$, respectively. In all patients, the amount of fluid infused before using the rapid fluid infuser was between 500 ml and 10,000 ml, compared to 1,000 ml and 6,200 ml with the rapid fluid infuser. The mean amount of fluid per min. via the rapid fluid infuser was 85.5 ml. Vital signs were stabilized in 11 patients, 6 of the 11 were discharged alive. Conclusion: The mean amount of fluid delivered per min. via the rapid fluid infuser was much less than expected; thus, there should be clinical guidelines on volume resuscitation with a rapid fluid infuser in the ED. In the future, prospective, multicenter, clinical-data collection is needed for a more sophisticated study.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.423-424
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• 2010

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.27 no.4
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• pp.394-402
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• 2023

Backgrounds/Aims: Acute pancreatitis is an emergency presentation, which can range from mild to life threatening. Intravenous fluids are the cornerstone of management. Although the WATERFALL trial described the optimal fluid rate in mild/moderate pancreatitis, this trial excluded patients with moderate-severe/severe pancreatitis. The aim of this study was to establish clinical practice regarding intravenous fluid administration in acute pancreatitis and assess its effect on mortality. Methods: Prospective multi-centre audit of patients with acute pancreatitis was conducted. Data were collected regarding intravenous fluid administration within 72 hours of admission. The primary outcome was 30-day mortality. Multivariable logistic regression was used to identify predictors of 30-day mortality. Results: Those with severe pancreatitis received more fluid; median 5.7 L versus 4 L in 72 hours (p = 0.003). Participants with severe pancreatitis who died within 30 days received a median of 2,750 mL in the first 24 hours, compared to 4,000 mL in those who survived. The following factors were significant predictors of 30-day mortality: age, Glasgow score, C-reactive protein, ischaemic heart disease, and pancreatitis aetiology. Overall, volume of intravenous fluid was not associated with mortality. However, the effect of intravenous fluid volume on mortality differed significantly depending on pancreatitis severity. In severe pancreatitis, increased volume of intravenous fluid was associated with significant reductions in mortality (odds ratio = 0.655; 0.459-0.936; p = 0.020). Conclusions: In severe pancreatitis, more aggressive fluid prescription was associated with decreased mortality; however, this was not the case in milder disease. Further prospective trials guiding fluid resuscitation in severe pancreatitis are needed, as the impact of fluid on this population appears to differ from that in those with milder disease.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.3075-3083
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• 1994

The applications of the electrical transmission line theory to the pressure propagation characteristics in the volume loaded fluid transmission line with step and impulse input wave is demonstrated in this paper. The method is based on the premise that the time response is the inverse Fourier transform of frequency spectrum of the wave which spectrum is a product of frequency spectrum of input pressure wave and system transfer function. The frequency response and transient response of step and impulse input wave in the volume loaded fluid transmission line is analysed by the Laplace transform and inverse Laplace transform with FFT numerical algorithm. The numerical solution of the distributed friction model is compared with the average friction model and the infinite product model. And the result is showed that FFT method may have major advantages for the simulation of fluid circuitary.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.14 no.1
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• pp.83-91
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• 2007

Purpose: This study was done to examine the differences in the fluid volume deficit according to levels of depression and BMI. The results of this study will provide fundamental information for developing nursing interventions for hydration management. Method: The participants were 51 hospitalized elderly people in K province. Data were collected from September 4 to 30, in 2006. A structured questionnaire was used for the data collection. Frequencies, Percentages, Means, Standard Deviation, t-test, Mann-Whitney U test, and Kruskal-Wallis test were used with the SPSS Program to analyze the data. Results: There were significant differences in the fluid volume deficit between elders in the depressed and normal groups. Participants who had a BMI of less than $21kg/m^2$ had the highest fluid volume deficit. Conclusion: Water is an essential part of the human body although it is least studied in elderly people. Health care providers need to increase awareness of the importance of hydration status among hospitalized elderly people with chronic illnesses.

• Computers and Concrete
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• v.21 no.5
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• pp.569-582
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• 2018

In this study, nonlinear vibration and stability of a polymeric pipe reinforced by single-walled carbon naotubes (SWCNTs) conveying fluid-nanoparticles mixture flow is investigated. The Characteristics of the equivalent composite are determined using Mori-Tanaka model considering agglomeration effects. The surrounding elastic medium is simulated by orthotropic visco-Pasternak medium. Employing nonlinear strains-displacements, stress-strain energy method the governing equations were derived using Hamilton's principal. Differential quadrature method (DQM) is used for obtaining the frequency and critical fluid velocity. The influence of volume percent of SWCNTs, agglomeration, geometrical parameters of pipe, viscoelastic foundation and fluid velocity are shown on the frequency and critical fluid velocity of pipe. Results showed the increasing volume percent of SWCNTs leads to higher frequency and critical fluid velocity.

• International Journal of Naval Architecture and Ocean Engineering
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• v.1 no.1
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• pp.20-28
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• 2009

In thus paper we validate a numerical model for wave-structure interaction by comparing numerical results with laboratory data. The numerical model is based on the Navier-Stokes (N-S) equations for an incompressible fluid. The N-S equations are solved by a two-step projection finite volume scheme and the free surface displacements are tracked by the volume of fluid (VOF) method The numerical model is used to simulate solitary waves and their interaction with a group of slender vertical piles. Numerical results are compared with the laboratory data and very good agreement is observed for the time history of free surface displacement, fluid particle velocity and wave force. The agreement for dynamic pressure on the cylinder is less satisfactory, which is primarily caused by instrument errors.