• Journal of Biomedical Engineering Research
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• v.11 no.2
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• pp.257-268
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• 1990

A system has been developed for monitoring the effect of neuromuscular blocking frugs and the neuromuscular function during anesthesia and surgery. This system is composed of software and hardware, the latter are nerve stimulator, force transducer, interface board(preamplifier, filter, peripheral input/output) and personal computer (apple ll) , the former are programmed in ASSEMBLY and BASIC language. The nerve stimulator which is controlled by personal computer is capable of delivering single shocks at o.)Hz, train of four at 2Hz and tetanic stimulation at 30, 100, 200Hz. The response, adduction of the thumb, is sensed by the force transducer. The output of the force transducer Is amplified, filtered, converted digital signal and then processed by the per- sonal computer. The personal computer quantia4es twitch and traln of four tesponse and calculates the 74 ratio (Ta/Tl )between the first and fourth response of train of four. This ratio is used to estimate the level of the neuromuscular block. This system has reaserch potential for determining the effect of newer neuromuscular blocking drugs for comparlsion with presently used drugs of alternatively, for delerminig the effects of blocking drugs in altered physilogical states.

• Elastomers and Composites
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• v.49 no.1
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• pp.1-12
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• 2014

Blocking of fuel filter in aircraft greatly can affect loss of pilot's life and of the aircraft. The investigation of failures is, thus, of vital importance in preventing incidents in advance. The fuel filter of aircraft plays an important role in filtering various debris from jet fuel. It filters impurities smaller than 10 ${\mu}m$ particles from jet fuel provided with the speed of 1,330 pounds per hour. It must be replaced per 500 h on the basis of operating time. However, even before reaching 500 h, the warning sign lighted on due to blocking of fuel filter. Recently, these similar defects have happened repeatedly. Therefore, in this study, the cause of blocking fuel filter in aircraft was investigated using various analytical techniques such as FT-IR microscopy, FE-SEM/EDS, and total sulfur determinator. Consequently, the blocking material of fuel filter was identified to an accelerator from the integral fuel tank sealant. And a mechanism for the formation of the blocking material of fuel filter by an accelerator blooming phenomenon in fuel tank was suggested.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.1
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• pp.19-31
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• 2022

Damages by jellyfish are occurring frequently around the world. Among them, accidents caused by jellyfish stings are serious enough to cause death. So we designed a jellyfish blocking net and analyzed its stability to prevent sting caused by jellyfish entering the beach. To this end, the dynamic behavior of the jellyfish blocking net according to the current speed (0.25-1.0 m/s) and the net type (50, 100 and 150 mm) on the upper part of the blocking net was modeled using the mass spring model. As a result of simulations for the model, the horizontal tension (horizontal component of the mooring tension) of the mooring line increased with the decrease in the mesh size on the upper part of the blocking net at all current speeds, but exceeded the holding force at high tides faster than 0.5 m/s and exceeded the holding force at all current speeds at low tide. Therefore, the jellyfish blocking nets showed poor stability overall. The depth of the float line had a little difference according to the upper mesh size and increased lineary proportional to the current speed. However, the float line sank too much to block the incoming jellyfish. These analysis results helped us find ways to improve the stability of the jellyfish blocking net, such as adjusting the length of the mooring line and improving the holding power. Therefore, it is expected that this technology will be applied us various underwater structures to discover the weaknesses of the structures and contribute to increasing the stability in the future.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.57-64
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• 2007

The purpose of this study was to investigate comparative analysis of the vertical ground reaction force variables during landing from vertical jump blocking in volleyball through GRF analysis system. The subjects participated in this study were 6 male university volleyball player and 6 male acted as a control group. The results are as follows: 1. The skilled group was longer than the unskilled group in flight time during vertical jump blocking. 2. The skilled group was faster than the unskilled group in tFz2 during landing from vertical jump blocking. 3. The skilled group was higher than the unskilled group in Fz2 during landing from vertical jump blocking. 4. The skilled group was higher than the unskilled group in Fz2LR during landing from vertical jump blocking. 5. The skilled group was higher than the unskilled group in impulse during landing from vertical jump blocking. Consequently, during landing from vertical jump, the landing strategy of the skilled group was found as a form of a stiff landing. Therefore, this landing strategy will be required to strengthen of hip and knee extensors and ankle plantar flexors for injury prevention.

• Korean Security Journal
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• no.50
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• pp.307-337
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• 2017

The freedom of assembly is the fundamental freedoms guaranteed by the Constitution. However, as far as our reality is concerned, the freedom of assembly is guaranteed only when it is under the control of the police, and otherwise it is perceived as an object to be suppressed. Police say even that they will not tolerate even a small illegal law while referring to the "broken window theory". Therefore, regardless of the peaceful nature of the rally, it is too obsessed with 'compliance'. This attitude is causing the citizens who participated in the assembly to be put to the object to be suppressed. This paper analyzes the requirements and current status of police force, focusing on the vehicle-wall-blocking and water cannon as a means of using the police force, which is a recent problem, and suggests ways to improve it. First of all, the installation of the wall cuts off the essential communication function of the assembly by separating the meeting place from the object of protest. Thus, despite the warning for prevention in the face of illegal acts, other than installing a barrier, it should be allowed only in the 'urgent case where there is a risk of causing damage to the life, body or property of the person'. Without this urgency, the vehicle-wall-blocking should not be allowed to be proactive as well as preventive. Secondly, the water cannon is a police force that is likely to harm people's life and body. Therefore, aiming shots, which could pose a significant risk to the human body, should in principle be prohibited. However, considering its risk, it should be supplementary used only when there is no other alternative, only when the direct risk to the legal interest of the other person or the order of public well-being is 'obvious'. In addition, as for the use standard of such a thing, it is necessary to be specified by law.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.4
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• pp.520-528
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• 2015

The piezoelectric-hydraulic actuator is a hybrid device that consists of a hydraulic pump driven by a piezo-stack coupled to a conventional hydraulic cylinder. The actuator is of compact size, but can produce a moderate energy output. Such hybrid actuators are currently being researched and developed in many industrialized countries due to the requirement for high performance and compact flight systems. In a previous study, we designed and manufactured a unidirectional hybrid actuator. However, the blocking force was not as high as expected. Therefore, in this study, we redesigned the pump chamber and hydraulic cylinder and also improved the system by removing the air bubbles. Two different types of piezo-stacks were used. In order to achieve bidirectional capabilities in the actuator, commercial solenoid valves were used to control the direction of the output cylinder. Experimental testing of the actuator in unidirectional and bidirectional modes was performed to examine performance issues related to driving frequency, bias pressure, reed valve thickness, etc. The results showed that the maximum blocking force was measured as 970.2N when the frequency was 185Hz.

• Composites Research
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• v.20 no.3
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• pp.50-54
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• 2007

The Ionic Polymer Metal Composite (IPMC), an electro-active polymer, has many advantages including bending actuation, low weight, low power consumption, and flexibility. These advantages coincide with the requirements of a bio-related application. Thus, IPMC is promising materials for bio-mimetic actuator and sensor applications. Before applying IPMC to actual application, basic mechanical properties of IPMC should be studied in order to utilize IPMC for practical uses. Therefore, IPMCs are fabricated to investigate the mechanical characteristics. Nafion is used as a base ionic polymer. Mason samples cast with various thicknesses are used to test the thickness effects of IPMC. Subsequently, IPMC is fabricated using the chemical reduction method. The deformation, blocking force and frequency response of the IPMC actuator are important properties. In this present study, the performances of the IPMC actuators, including the deformation, blocking force and natural frequency, are then obtained according to only the input voltage and IPMC dimensions. Finally, the empirical performance model and the equivalent stiffness model of the IPMC actuator are established using experiments results.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.5
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• pp.324-333
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• 2013

Recently, rudder erosion due to cavitation has been frequently reported on a semi-spade rudder of a high-speed large ship. This problem raises economic and safety issues when operating ships. The semi-spade rudders have a gap between the horn/pintle and the movable wing part. Due to this gap, a discontinuous surface, cavitation phenomenon arises and results in unresolved problems such as rudder erosion. In this study, we made a rudder model for 2-D experiments using the NACA0020 and also manufactured gap flow blocking devices to insert to the gap of the model. In order to study the gap flow characteristics at various rudder deflection angles($5^{\circ}$, $10^{\circ}$, $35^{\circ}$) and the effect of the gap flow blocking devices, we carried out the velocity measurements using PIV(Particle Image Velocimetry) techniques and cavitation observation using high speed camera in Seoul National University cavitation tunnel. To observe the gap cavitation on a semi-spade rudder, we slowly lowered the inside pressure of the cavitation tunnel until cavitation occurred near the gap and then captured it using high-speed camera with the frame rate of 4300 fps(frame per second). During this procedure, cavitation numbers and the generated location were recorded, and these experimental data were compared with CFD results calculated by commercial code, Fluent. When we use gap flow blocking device to block the gap, it showed a different flow character compared with previous observation without the device. With the device blocking the gap, the flow velocity increases on the suction side, while it decreases on the pressure side. Therefore, we can conclude that the gap flow blocking device results in a high lift-force effect. And we can also observe that the cavitation inception is delayed.

• Journal of computational fluids engineering
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• v.17 no.3
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• pp.18-24
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• 2012

The aerodynamic performance of the pantograph on a high speed train was compared for different pantograph covers which are designed to block the aero-acoustic noise from the pantograph. For the study, two types of cover are designed: wedge and cone types. The lift force of pantograph with cover was compared with the force of pantograph only. The comparison clarified that the cone type cover increases the sideslip angle of the flow and decreases the lift force considerably. However, the wedge type cover changes the flow direction upward and increases the lift force of the pan head. This increment of lift force compensates the decrement of lift force caused by the blocking of the flow into the pantograph lower frame due to cover. Therefore, in case of the wedge type cover, the overall lift force changes slightly compared with the cone type cover.

• Elastomers and Composites
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• v.51 no.1
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• pp.24-30
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• 2016

Sole in the footwear usually modified with foaming agent on the polymer resin to improve the lightweightness and crush-cushion effect. In this study, we investigated rheological properties for polymer resin filled with the different type and concentration of foaming agent, capsule type foaming agent and organo-chemical foaming agent, under the time sweep test. Curing times of each polymer resin with different kind of foaming agent are delayed than reference material (epoxy resin with curing agent). In case of adding capsule type foaming agent, however, there is appropriate concentration to reduce the curing time, relatively. When foaming agent is activated, foaming force inflates the sample in contrast to condensation force of curing and then axial normal force develop to the (+) direction. Interestingly, by increase concentration of foaming agent, there is a specific point to break down the axial normal force development. The reason for this phenomenon is that coalescence of foams induce the blocking of axial normal force development.