• Tribology and Lubricants
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• v.22 no.4
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• pp.203-210
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• 2006

Two kinds of crankshaft oil supply system which were called continuous and discontinuous oil sup-ply system have recently been adopted in engine developing process. In order to clarify the lubrication characteristics for theses systems, in this paper, the comparison studies on supplied oil temperature, pressure, aspect ratio of bearings, and radial clearance were carried out for the main and the connecting rod bearing using computational fluid dynamic analysis.

• Journal of Hospice and Palliative Care
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• v.13 no.4
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• pp.243-251
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• 2010

Purpose: This study was conducted to investigate how nurses who take care of terminal patients perceive fluid therapy and how this therapy is currently being used in hospitals. Methods: This survey included 200 nurses, 87 of whom were working in the oncology units of 3 university hospitals in Seoul, Korea, and 113 were working in 18 hospice centers. The data for this study were collected by means of structured questionnaires and analyzed by using the Statistical Analysis System software. The differences in perception towards fluid therapy between nurses working in oncology units and those working in hospice centers were examined using the $x^2$ test and analysis of covariance. Results: Fluid therapy was perceived more negatively by the nurses from hospice centers than by those from oncology units. Continuous subcutaneous infusion was used in hospice centers, but not in oncology units. In addition, the average amount of fluid infused daily differed significantly between the oncology units and hospice centers. Conclusion: Our results show that there were differences in the perception towards fluid therapy between nurses in different clinical settings. Nurses caring for terminal and palliative care patients should not simply provide or withhold fluid therapy, but rather develop a wider range of views on fluid therapy, focusing on effective alternative interventions.

• The Korean Journal of Nuclear Medicine
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• v.35 no.1
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• pp.81-82
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• 2001

A 47-year-old man with end-stage renal disease due to diabetic nephropathy underwent a peritoneal scintigraphy to evaluate the cause of recently developed scrotal swelling. Two liters of dialysate mixed with 111 MBq of Tc-99m sulfur colloid were administered into the peritoneal cavity via the dialysis catheter. Various anterior images of the abdomen and pelvis were obtained at 15 min, 2 hr and 4 hr after the tracer instillation. At 15 min, anterior images of the abdomen and pelvis demonstrated linear tracts of activity through both inguinal canals, which were more prominent in the right side (A). Images at 2 hr revealed a passage of the radioactive fluid into the right hemiscrotum. At the same time, there was a considerable accumulation of activity in the right inguinal canal (B). In the delayed image, there was a progressive accumulation of activity in the inguinal canals and a prominent passage of the tracer into the scrotum (C). Both abdominal and inguinal hernias are commonly associated with continuous ambulatory peritoneal dialysis (CAPD). Overall incidence of CAPD-induced hernia ranges from 2.7% to 25%.$^{1)}$ Inguinal hernias were frequently manifested as scrotal swelling. Leakages of dialysate fluid into the scrotum has been noted in CAPD patients with scrotal swelling, with or without clinical findings of inguinal hernia.$^{1,2)}$ In the present case, the right side had leakage from a clinical inguinal hernia and the left side, leakage from a subclinial inguinal hernia. A subclinical inguinal hernia was easily demonstrable with peritoneal scintigraphy. Peritoneal scintigraphy is extremely helpful in the evaluation of scrotal swelling in a patient on CAPD.

• Journal of Biomedical Engineering Research
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• v.36 no.3
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• pp.61-68
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• 2015

In this paper, we studied the effects of intersection angles of the flow-foucusing type droplet generation device inlet channel on droplet diameter using numerical simulation modeling. We modeled different intersection angles with a fixed continuous channel width, dispersed channels width, orifices width, and expansion channels width. Numerical simulations were performed using COMSOL Multiphysics$^{(R)}$ to solve the incompressible Navier-Stokes equations for a two-phase flow in various flow-focusing geometries. Modeling results showed that an increase of the intersection angle causes an increase in the modification of the dispersed flow rate ($v^{\prime}{_d}$), and the increase of the modification of the continuous flow rate ($v^{\prime}{_c}$) obstructs the dispersed phase fluid flow, thereby reducing the droplet diameter. However, the droplet diameter did not decrease, even when the intersection angle increased. The droplet diameter decreased when the intersection angle was less than $90^{\circ}$, increased at an intersection angle of $90^{\circ}$, and decreased when the intersection angle was more than $90^{\circ}$. Furthermore, when the intermediate energy deceased, there was a decrease in the droplet diameter when the intersection angle increased. Therefore, variations in the droplet diameter can be used to change the intersection angle and fluid flow rate.

• Journal of Korean Neurosurgical Society
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• v.29 no.9
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• pp.1209-1214
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• 2000

Objectives : The measurement of resistance to cerebrospinal fluid outflow($R_o$) can clearly delineate cerebrospinal fluid dynamics in patients with ventricular dilatation and can help in selecting patients to undergo shunt placement. With regards to type of infusion method, bolus injection is known to be more practical and safer than continuous infusion. The purpose of this study was to obtain $R_o$ of normal adults using lumbar bolus injection method. Material and Methods : Twenty adults aged 25 to 52 years were studied using lumbar bolus injection method. Fifteen patients with hemifacial spasm and five with cerebral concussion underwent $R_o$ measurement under propofol general anesthesia and local anesthesia, respectively. Results : The mean values of $R_o$ determined 1 minute and 2 minutes after bolus injection were $4.8{\pm}1.7$ and $4.4{\pm}1.6mmHg/ml/min$, respectively. There was no significant difference of $R_o$ between propofol general anesthesia group and local anesthesia group. Two patients showed $R_o$ greater than 6mmHg/ml/min. One patient revealed unexpectedly high level of $R_o$ due to severe spinal stenosis. Conclusion : Mean Ro in this study was higher than that of Shapiro's study. Borderline Ro near 6mmHg/ml/min should be regarded with caution and compared with clinical symptoms and results of other studies. Patients with severe spinal stenosis should be evaluated with caution.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.5
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• pp.424-430
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• 2005

The oral cavity is humid environment mainly due to the continuous salivary flow. The reaction of oral mucosa to fluid flow is important for homeostasis and pathogenesis. The objective of this study is the screening the change of gene expression after the application of fluid induced shear stress (FISS) on the gingival fibroblast using cDNA microarray assay. The immortalized human gingival fibroblasts were grown and FISS was applied using a cone viscometer at a rotational velocity of 40 rpm, respectively for periods of 2 and 4 hours. The synthesis of cDNA was done from the extracted total RNA and cDNA microarray assay was done subsequently. The genes that showed over 1.6 in the Cy3/Cy5 or the Cy5/Cy3 value were regarded as genes influenced significantly by the FISS application ion (/M/>0.7). The " RUNX-1" was increased its expression in 2 hours group and " RUN and SH3 domain containing 1" was increased its expression in 4 hours group. The "CC020415", "cyclin L1", "interferon regulatory factor1", "early growth response 1", "immediate early response 2", and "immediate early response 3" genes were increased their expression in 2 and 4 hours after FISS application. In conclusion, we could find many genes that were probably related to the FISS application. Interestingly, most of them were placed in similar molecular pathways and these findings improve the reliability of chip data and usefulness in overall screening. From this experiment, we could find many items for further study and it will make improvement in the understanding of intracellular events in response to FISS.

• Advances in nano research
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• v.16 no.4
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• pp.341-352
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• 2024

This study investigates the heat and mass transfer characteristics of a MoS₂ nanoparticle suspension in ethylene glycol over a porous stretching sheet. MoS₂ nanoparticles are known for their exceptional thermal and chemical stability which makes it convenient for enhancing the energy and mass transport properties of base fluids. Ethylene glycol, a common coolant in various industrial applications is utilized as the suspending medium due to its superior heat transfer properties. The effects of variable thermal conductivity, variable mass diffusivity, thermal radiation and thermophoresis which are crucial parameters in affecting the transport phenomena of nanofluids are taken into consideration. The governing partial differential equations representing the conservation of momentum, energy, and concentration are reduced to a set of nonlinear ordinary differential equations using appropriate similarity transformations. R software and MATLAB-bvp5c are used to compute the solutions. The impact of key parameters, including the nanoparticle volume fraction, magnetic field, Prandtl number, and thermophoresis parameter on the flow, heat and mass transfer rates is systematically examined. The study reveals that the presence of MoS₂ nanoparticles curbs the friction between the fluid and the solid boundary. Moreover, the variable thermal conductivity controls the rate of heat transfer and variable mass diffusivity regulates the rate of mass transfer. The numerical and statistical results computed are mutually justified via tables. The results obtained from this investigation provide valuable insights into the design and optimization of systems involving nanofluid-based heat and mass transfer processes, such as solar collectors, chemical reactors, and heat exchangers. Furthermore, the findings contribute to a deeper understanding of stretching sheet systems, such as in manufacturing processes involving continuous casting or polymer film production. The incorporation of MoS₂-C₂H₆O₂ nanofluids can potentially optimize temperature distribution and fluid dynamics.

• Journal of the Korean institute of surface engineering
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• v.42 no.3
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• pp.133-138
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• 2009

Effects of bipolar pulse driving frequency between 50 kHz and 250 kHz on the discharge shapes were analyzed by measuring plasma characteristics by OES (Optical Emission Spectroscopy) and Langmuir probe. Plasma characteristics were modeled by a simple electric field analysis and fluid plasma modeling. Discharge shapes by a continuous dc and bipolar pulsed dc were different as a dome-type and a vertical column-type at the cathode. From OES, the intensity of 811.5 nm wavelength, the one of the main peaks of Ar, decreased to about 43% from a continuous dc to 100 kHz. For increasing from 100 kHz to 250 kHz, the intensity of 811.5 nm wavelength also decreased by 46%. The electron density decreased by 74% and the electron temperature increased by 36% at the specific position due to the smaller and denser discharge shape for increasing pulse frequency. Through the numerical analysis, the negative glow shape of a continuous dc were similar to the electric potential distribution by FEM (Finite Element Method). For the bipolar pulsed dc, we found that the electron temperature increased to maximum 10 eV due to the voltage spikes by the fast electron acceleration generated in pre-sheath. This may induce the electrons and ions from plasma to increase the energetic substrate bombardment for the dense thin film growth.

• Clinical Endoscopy
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• v.57 no.2
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• pp.246-252
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• 2024

Background/Aims: Endoscopic ultrasound (EUS)-guided hepaticogastrostomy (EUS-HGS) is useful for patients with biliary cannulation failure or inaccessible papillae. However, it can lead to serious complications such as bile peritonitis in patients with ascites; therefore, development of a safe method to perform EUS-HGS is important. Herein, we evaluated the safety of EUS-HGS with continuous ascitic fluid drainage in patients with ascites. Methods: Patients with moderate or severe ascites who underwent continuous ascites drainage, which was initiated before EUS-HGS and terminated after the procedure at our institution between April 2015 and December 2022, were included in the study. We evaluated the technical and clinical success rates, EUS-HGS-related complications, and feasibility of re-intervention. Results: Ten patients underwent continuous ascites drainage, which was initiated before EUS-HGS and terminated after completion of the procedure. Median duration of ascites drainage before and after EUS-HGS was 2 and 4 days, respectively. Technical success with EUS-HGS was achieved in all 10 patients (100%). Clinical success with EUS-HGS was achieved in 9 of the 10 patients (90%). No endoscopic complications such as bile peritonitis were observed. Conclusions: In patients with ascites, continuous ascites drainage, which is initiated before EUS-HGS and terminated after completion of the procedure, may prevent complications and allow safe performance of EUS-HGS.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.523-528
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• 2013

In recent years, many efforts are increasingly being made to conserve the natural environment with enhanced emission standards and air quality standards. Also there are various methods necessary to be researched to minimize the emission of air pollutants. In particular, boilers of industrial facilities are major portions of the air pollution. The front duct which needs to be designed to reduce the gases to the electrostatic precipitator requires a bent tube, a reduction/extend tube and an auxiliary equipment, that is, a guide vane. This paper proposes an optimum design of the guide vane by a case study for electrostatic precipitator's flow uniformity. The operating conditions of this study are as follows: BMCR (Boiler Maximum Continuous Rate) and MGR (Maximum Guaranteed Rate) are 75%, 50%, and 30%; turbulent fluid dynamics model is based upon K-${\varepsilon}$ formulation. Presentation of the computed motion of particles is found to be quite useful to predict the precipitator performance by use CFD (Computational Fluid Dynamics).