• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.4
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• pp.1-8
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• 2011

Injection molding machine is the assembly of many kinds of mechanical and fluid power part and electro-electronic control system. From in these, fluid power is a part where becomes the first core of this machine. Fluid power systems of injection molding machine are modelled and analyzed using a commercial program AMESim. The analysis model which is detailed about the parts applied a publishing catalog data. Sub system models which is divided according to functional operation are made and its analysis results shows how design parameters work on operational characteristics like displacement, pressure, flow rates at each node and so on. Total fluid power circuit model is also made and analyzed. The results made by analysis will be used design of fluid power circuit of injection molding machine.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.4
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• pp.24-31
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• 2011

Double-color Injection molding machine is the assembly of many kinds of mechanical, fluid power part and electric electronic control system. From in these, fluid power is a part where becomes the first core of this machine. Fluid power systems of double-color injection molding machine are modelled and analyzed using a commercial program AMESim. Partial system models which is divided according to functional operation are made and its analysis results shows how design parameters work on operational characteristics like pressure, flow rates, displacement at each node and so on. Analysis modeling and compared the data which gets from experiment and the analysis result which has a reliability got data. The results made by analysis will be used design of fluid power circuit for developing a double-color injection molding machine.

• Design & Manufacturing
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• v.15 no.1
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• pp.66-71
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• 2021

In this study, die turning injection(DTI) mold design for manufacturing reservoir fluid tanks used for cooling in-vehicle batteries, inverters, and motors was conducted based on multi-field CAE. Part design, performance evaluation, and mold design of the reservoir fluid tank was performed. The frequency response characteristics through modal and harmonic response analysis to satisfy the automotive performance test items for the designed part were examined. Analysis of re-melting characteristics and structural analysis of the driving part for designing the rotating die of the DTI mold were performed. Part design was possible when the natural frequency performance value of 32Hz or higher was satisfied through finite element analysis, and the temperature distribution and deformation characteristics of the part after injection molding were found through the first injection molding analysis. In addition, it can be seen that the temperature change of the primary part greatly influences the re-melting characteristics during the secondary injection. The minimum force for driving the turning die of the designed mold was calculated through structural analysis. Hydraulic system design was possible. Finally, a precise and efficient DTI mold design for the reservoir fluid tank was possible through presented multi-field CAE process.

• Smart Structures and Systems
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• v.34 no.1
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• pp.51-62
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• 2024

Application of biopolymers to improve the mechanical properties of soils has been extensively reported. However, a comprehensive understanding of various engineering applications is necessary to enhance their effectiveness. While numerous experimental studies have investigated the use of biopolymers as injection materials, a detailed understanding of their injection behavior in soil through numerical analyses is lacking. This study aimed to address this gap by employing pore network modeling techniques to analyze the injection characteristics of biopolymer solutions in soil. A pore network was constructed from computed tomography images of Ottawa 20-30 sand. Fluid flow simulations incorporated power-law parameters and governing equations to account for the viscosity characteristics of biopolymers. Agar gum was selected as the biopolymer for analysis, and its injection characteristics were evaluated in terms of concentration and pore-size distribution. Results indicate that the viscosity properties of biopolymer solutions significantly influence the injection characteristics, particularly concerning concentration and injection pressure. Furthermore, notable trends in injection characteristics were observed based on pore size and distribution. Importantly, in contrast to previous studies, meaningful correlations were established between the viscosity of the injected fluid, injection pressure, and injection distance. Thus, this study introduces a novel methodology for integrating pore network construction and fluid flow characteristics into biopolymer injections, with potential applications in optimizing field injections such as permeation grouting.

• The Korean Journal of Pain
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• v.31 no.2
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• pp.102-108
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• 2018

Background: Nefopam is a non-opioid, non-steroidal analgesic drug with fewer adverse effects than narcotic analgesics and nonsteroidal anti-inflammatory drugs, and is widely used for postoperative pain control. Because nefopam sometimes causes side effects such as nausea, vomiting, somnolence, hyperhidrosis and injection-related pain, manufacturers are advised to infuse it slowly, over a duration of 15 minutes. Nevertheless, pain at the injection site is very common. Therefore, we investigated the effect of warmed carrier fluid on nefopam injection-induced pain. Methods: A total of 48 patients were randomly selected and allocated to either a control or a warming group. Warming was performed by diluting 40 mg of nefopam in 100 ml of normal saline heated to $31-32^{\circ}C$ using two fluid warmers. The control group was administered 40 mg of nefopam dissolved in 100 ml of normal saline stored at room temperature ($21-22^{\circ}C$) through the fluid warmers, but the fluid warmers were not activated. Results: The pain intensity was lower in the warming group than in the control group (P < 0.001). The pain severity and tolerance measurements also showed statistically significant differences between groups (P < 0.001). In the analysis of vital signs before and after the injection, the mean blood pressure after the injection differed significantly between the groups (P = 0.005), but the heart rate did not. The incidence of hypertension also showed a significant difference between groups (P = 0.017). Conclusions: Use of warmed carrier fluid for nefopam injection decreased injection-induced pain compared to mildly cool carrier fluid.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.67-68
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• 2006

This study suggests a precision flow control system that enables fluid injection of a few grams at a time in a few ms time duration. The fluid injection system suggested here consists of a high pressure fluid pump, a 3 way 3 position directional control valve, an injector and an orifice. The orifice is located between the directional control valve and the injector. By supplying current signal to the directional control valve, the prescribed small amount of fluid can be supplied to a plant through the injector. The control robustness of the suggested system against the disturbances like the pressure change in a plant and the viscosity variation of the injected fluid is secured easily by using an orifice with very small inside diameter and setting the supply pressure with comparatively high value. The control performances of the suggested system are verified by numerical simulations and experiments. The outcomes of this research could be applied to the common rail injection control of lubrication oil for large size marine diesel engines, and other industrial plants.

• Tunnel and Underground Space
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• v.27 no.5
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• pp.324-332
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• 2017

In this paper, a numerical analysis of one-dimensional viscous fluid flow in a rock joint using UDEC code is performed to evaluate the effect of design parameters on injection performance. We consider injection pressure, fluid compressibility, time dependence of yield strength and viscosity of injected grout fluid, and mechanical deformation of joint as the design parameters, and penetration length and flow rate of injection are investigated as the injection performance. Numerical estimations of penetration length and flow rate were compared to analytical solution and were well comparable with each other. We showed that cumulative injection volume can be over-estimated by 1.2 times than the case that the time-dependent viscosity evolution is not considered. We also carried out a coupled fluid flow and mechanical deformation analysis and demonstrated that injection-induced joint opening may result in the increment of cumulative volume by 4.4 times of that from the flow only analysis in which joint aperture is kept constant.

• The Korean Journal of Physiology
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• v.11 no.1
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• pp.21-26
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• 1977

Many cases have been reported that a post spinal headache can be relieved immediately by an epidural injection of saline; and autologous blood also has recently been used successfully instead of saline. The changes of the cerebrospinal fluid pressure in 40 cases were observed in the present study in support of the concept; that a continuous leakage in association with hypovolemia and hypotension of the cerebrospinal fluid is the primary cause of a post spinal headache. Subarachnoid pressure increased immediately with saline injection into the lumber epidural space. A spinal needle was inserted into the subarachnoid space at the level of $L2{\sim}3$ and opening pressure of the cerebrospinal fluid was read. An epidural Tuohy needle was insertad at the$L3{\sim}4$ and 25m1 of saline was injected into the epidural space and the cerebrospinal fluid pressure was read in the sitting position. $\underline{Sitting\;Position:}$ Mean pressure after injection $555{\pm}(110.9)mm\;H_2O$, Pressure rise rise (%) 51.3%, Mean opening pressure $366{\pm}(52.2)mm\;H_{2}O$, $\underline{Lateral\;position:}$ Mean pressure after injection $308{\pm}(70.8)mm\;H_{2}O$, Pressure(%) 86.7%, Mean opening pressure $165{\pm}(42.6)mm\;H_{2}O$. These pressure changes responded almost simultaneously as saline was injected. This pressure rise of 51.3% in the sitting position and 86.7% in the lateral position are clinically very significant. Therefore, it is most possible that the immediate relieve of post, spinal headache by injection of fluid into the epidural space is simultaneous with the increase of the cerebrospinal fluid pressure.

• Tunnel and Underground Space
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• v.23 no.6
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• pp.493-505
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• 2013

This numerical study investigates seismicity and fault slip induced by fluid injection in deep geothermal reservoir with pre-existing fractures and fault. Particle Flow Code 2D is used with additionally implemented hydro-mechanical coupled fluid flow algorithm and acoustic emission moment tensor inversion algorithm. The output of the model includes spatio-temporal evolution of induced seismicity (hypocenter locations and magnitudes) and fault deformation (failure and slip) in relation to fluid pressure distribution. The model is applied to a case of fluid injection with constant rates changing in three steps using different fluid characters, i.e. the viscosity, and different injection locations. In fractured reservoir, spatio-temporal distribution of the induced seismicity differs significantly depending on the viscosity of the fracturing fluid. In a fractured reservoir, injection of low viscosity fluid results in larger volume of induced seismicity cloud as the fluid can migrate easily to the reservoir and cause large number and magnitude of induced seismicity in the post-shut-in period. In a faulted reservoir, fault deformation (co-seismic failure and aseismic slip) can occur by a small perturbation of fracturing fluid (<0.1 MPa) can be induced when the injection location is set close to the fault. The presented numerical model technique can practically be used in geothermal industry to predict the induced seismicity pattern and magnitude distribution resulting from hydraulic stimulation of geothermal reservoirs prior to actual injection operation.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.676-679
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• 2008

Numerical simulations of fluid injection into particulate materials were conducted to observe cavity initiation and propagation using distinct element method. After generation of initial particles and wall elements, confining stress was applied by servo-control method. The fluid scheme solves the continuity and Navior-Stokes equations numerically, then derives pressure and velocity vectors for fixed grid by considering the existence of particles within the fluid cell. Fluid was injected as 7-step into the assembly in the x-direction from the inlet located at the center of the left boundary under confining stress condition, 0.1MPa and 0.5MPa, respectively. For each simulation, movement of particles, flow rate, fluid velocity, pressure history, wall stress including cavity initiation and propagation by interaction of flulid-paricles were analyzed.