• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.274-281
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• 2016

Background: Whole-body counters are widely used to evaluate internal contamination of the internal presence of gamma-emitting radionuclides. In internal dosimetry, it is a basic requirement that quality control procedures be applied to verify the reliability of the measured results. The implementation of intercomparison programs plays an important role in quality control, and the accuracy of the calibration and the reliability of the results should be verified through intercomparison. In this study, we evaluated the reliability of 2 whole-body counting systems using 2 calibration methods. Materials and Methods: In this study, 2 whole-body counters were calibrated using a reference male bottle manikin absorption (BOMAB) phantom and a Radiation Management Corporation (RMC-II) phantom. The reliability of the whole-body counting systems was evaluated by performing an intercomparison with International Atomic Energy Agencyto assess counting efficiency according to the type of the phantom. Results and Discussion: In the analysis of counting efficiency using the BOMAB phantom, the performance criteria of the counters were satisfied. The relative bias of activity for all radionuclides was -0.16 to 0.01 in the Fastscan and -0.01 to 0.03 in the Accuscan. However, when counting efficiency was analyzed using the RMC- II phantom, the relative bias of $^{241}Am$ activity was -0.49 in the Fastscan and 0.55 in the Accuscan, indicating that its performance criteria was not satisfactory. Conclusion: The intercomparison process demonstrated the reliability of whole-body counting systems calibrated with a BOMAB phantom. However, when the RMC-II phantom was used, the accuracy of measurements decreased for low-energy nuclides. Therefore, it appears that the RMC-II phantom should only be used for efficiency calibration for high-energy nuclides. Moreover, a novel phantom capable of matching the efficiency of the BOMAB phantom in low-energy nuclides should be developed.

• Journal of the Korea Safety Management & Science
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• v.17 no.3
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• pp.133-141
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• 2015

This study tried to identify the problems associated with the posture to be analyzed and tried to suggest guidelines for MSDs(Musculoskeletal Disorders) evaluation based on working posture. A total of 50 jobs from 3 different types of industries(electronics, hospitals, automobiles) were used for MSDs evaluation study which was done by 6 observers. Two indexes were applied to identify the problem in this study which were percentage of agreement and counter-time-error rate. Specifically, 'counter-time-error rate' represented a degree of consistency in terms of selecting the posture to be analyzed time after time. Main results of the study were as follows; 1) The average percentage of agreement for representative posture for whole body was relatively higher than that for representative postures for individual body parts, 2) The counter-time-error rate(%) has been reduced as the evaluation process has repeated for the same job. 3) The counter-time-error rate(%) for electronics, hospitals, and automobiles were 63.4%, 61.2%, and 67.3% respectively. 4) The counter-time-error rate(%) for the job with the work cycle of 0.5 to 2 minutes were lower than that of the jobs with the work cycles less than 0.5 minute or greater than 2 minute. 5) The work cycles and the number of trials had significant effects on counter-time-error rate while the types of industries did not have significant effects on counter-time-error rate. Some guidelines could be prepared from the results of the study. Probably, there should have an extension in terms of form and matter for this study in order to have more practical output.

• Journal of Radiation Protection and Research
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• v.34 no.1
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• pp.37-42
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• 2009

Whole body counters (WBCs) are used to monitor radiation workers for internal contamination of radionuclides at domestic nuclear power plants (NPPs). A WBC is a scintillation detector using sodium iodide (NaI) and provides the identification of inhaled radionuclide and the measurement of its internal radioactivity in a short time. However, it is often possible to estimate external contamination as internal contamination due to radionuclides attached to the skin of radiation workers and this leads to an excessively conservative estimation of radioactive contamination. In this study, several experiments using a WBC and the Korean humanoid phantom were performed to suggest the more systematic method of discrimination between external and internal contamination. Furthermore, a WBC geometry experiment was conducted to suggest the optimal WBC geometry in consideration of deposited areas inside the body for dominant radionuclides at NPPs. The procedure of measurement and estimation of internal radioactivity for radiation workers at NPPs was improved on the basis of experimental results. Thus, it is expected to prevent from estimating internal exposure dose conservatively owing to the application of accurate whole body counting program to NPPs.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.579-583
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• 2003

This study was to compare the Intake and Committed Effective Dose(CED) due to inhalation of I-131. The Intake and CED Calculations were based on KIDAC, LUDEP, MONDAL and IMBA computer codes.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.3
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• pp.233-239
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• 2013

This paper presents the analysis and control of the position of the COG (Center of Gravity) for a two-wheel balancing robot. The two-wheel balancing robot is required to maintain balance by driving two wheels only. Since the robot is not exactly symmetrical and its dynamics is changing with respect to moving parts, robust balancing control is difficult. Balancing performance becomes difficult when two arms hold a heavy object since the center of gravity is shifted out of the wheel axis. Novel design of a sliding waist mechanism allows the robot to react against the shift of the COG by moving the whole upper body to compensate for the imbalance of the mass as a counter balancer. To relocate the COG position accurately, the COG is analyzed by force data measured from two force sensors. Then the sliding COG mechanism is utilized to control the sliding waist position. Experimental studies are conducted to confirm the proposed design and method.

• Korean Journal of Applied Biomechanics
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• v.17 no.2
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• pp.167-176
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• 2007

The purpose of this study was to offer suitable model for performing Tippelt motion and data for training Tippelt motion through the quantitative kinematical analysis of Tippelt motion in parallel bars. The results of analysing kinematic variations through three-dimensional reflection analysis of three members of the national team as the objects of the study were shown as follows. 1. It seemed that the shoulder-joints which are stretched as much as possible affects the whole Tippelt motion while one is swinging downward. The time of process of the center of mass for the body reaching to the maximum flection point should be quick and body's moving from the vertical phase to the front direction should be controled as much as possible. 2. While one is swinging upward, the stability of flying motion could be made certain by the control of body's rapid moving to the front direction and stretching shoulder-joints and hip-joint to reverse direction. 3. While one is flying upward, the body should be erected quickly and lessening the angle of the hip-joint affects the elevation of flight. When the powerful counter turn motion is performed, the stable motion could be made. As a result of this study, It seems that sudden fall and the maximum stretch of shoulder-joints is important during performing Tippelt motion in parallel bars. Also, it concludes that the maximum bending of hip-joints at the starting point of upward swing, sudden stretch to the reverse direction of shoulder-joints and hip-joints when one is leaving bars, control of body's moving to the front direction, and lessening the angle of hip-joints at the flying phase is important.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.10
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• pp.1023-1030
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• 2015

The purpose of this paper is to present the basic mathematical modeling of a hexacopter, which could be used to develop proper methods for stabilization and trajectory control. A hexacopter consists of six rotors with three pairs of counter-rotating fixed-pitch blades. This mechanism is an under-actuated, dynamically unstable, six-degrees-of-freedom system. The whole motion of this object consists of translational and rotational motion in three dimensions, where the translational motion is created by changing the direction and magnitude of the upward propeller thrust. The hexacopter is controlled by adjusting the angular velocities of the rotors, which are spun by electric motors. It is assumed to be a rigid body; thus, the differential equation of the hexacopter dynamics can be derived from the Newton-Euler equation. The Euler-angle parametrization of the three-dimensional rotations contains singular points in the coordinate space that can cause failure of both the dynamical model and control. In order to avoid singularities, the rotations of the hexacopter are parametrized in terms of quaternions. This choice has been made considering the linearity of the quaternion formulation and their stability and efficiency. Further, control simulation of a hexacopter applying cascaded-PID control is also presented in this paper.

• Radiation Oncology Journal
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• v.15 no.3
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• pp.197-206
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• 1997

Purpose : Phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine to phosphatidic acid (PA) and choline. Recently, PLD has been drawing much attentions and considered to be associated with cancer Process since it is involved in cellular signal transduction. In this experiment, oleate-PLD activities were measured in various tissues of the living rats after whole body irradiation. Materials and Methods : The reaction mixture for the PLD assay contained $0.1\;\muCi\;1,2-di[1-^{14}C]palmitoyl$ phosphatidylcholine 0.5mM phosphatidylcholine, 5mM sodium oleate, $0.2\%$ taurodeoxycholate, 50mM HEPES buffer(pH 6.5), 10mM $CaCl_2$, and 25mM KF. phosphatidic acid, the reaction product, was separated by TLC and its radioactivity was measured with a scintillation counter. The whole body irradiation was given to the female Wistar rats via Cobalt 60 Teletherapy with field size of 10cmx loom and an exposure of 2.7Gy per minute to the total doses of 10Gy and 25Gy. Results : Among the tissues examined, PLD activity in lung was the highest one and was followed by kidney, skeletal muscle, brain, spleen, bone marrow, thymus, and liver. Upon irradiation, alteration of PLD activity was observed in thymus, spleen, lung, and bone marrow. Especially PLD activities of the spleen and thymus revealed the highest sensitivity toward $\gamma-rar$ with more than two times amplification in their activities In contrast, the PLD activity of bone marrow appears to be reduced to nearly $30\%$. Irradiation effect was hardly detected in liver which showed the lowest PLD activity. Conclusion : The PLD activities affected most sensitively by the whole-body irradiation seem to be associated with organs involved in immunity and hematopoiesis. This observation s1ron91y indicates that the PLD is closely related to the physiological function of these organs, Furthermore, radiation stress could offer an important means to explore the phenomena covering from cell Proliferation to cell death on these organs.

• Journal of Radiation Protection and Research
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• v.15 no.2
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• pp.17-25
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• 1990

Rats were ingested in drinking water 600mg/L of cadmium chloride solution during 3 months, then the distribution of Cd in major organs and hair were determined by neutron activation analysis. The results were as followings. 1. After administration for 24 hours using $^{115m}Cd$ as tracer, the distribution of blood was 0.03%, kidney 2.99% and liver 3.50% to determine with whole body counter. 2. Cd metal was rapidly excreted with kidney through blood and their accumulation appeared in liver and hair. 3. The comparative data to determine using neutron activation analysis. the content of cadmium of major organs in rats ingested of $CdCl_2$ during 3 month were shown to increase significantly both hair and liver. Above facts, hair samples were able to use as the diagnostic index to evaluate the accumulation of cadmium in liver.

• Advances in nano research
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• v.14 no.5
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• pp.435-442
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• 2023

Sports activities, including playing tennis, are popular with many people. As this industry has become more professionalized, investors and those involved in sports are sure to pay attention to any tool that improves athletes' performance Tennis requires perfect coordination between hands, eyes, and the whole body. Consequently, to perform long-term sports, athletes must have enough muscle strength, flexibility, and endurance. Tennis rackets with new frames were manufactured because tennis players' performance depends on their rackets. These rackets are distinguished by their lighter weight. Composite rackets are available in many types, most of which are made from the latest composite materials. During physical exercise with a tennis racket, nanocomposite materials have a significant effect on reducing injuries. Materials as strong as graphite and thermoplastic can be used to produce these composites that include both fiber and filament. Polyamide is a thermoplastic typically used in composites as a matrix. In today's manufacturing process, materials are made more flexible, structurally more vital, and lighter. This paper discusses the production, testing, and structural analysis of a new polyamide/Multi-walled carbon nanotube nanocomposite. This polyamide can be a suitable substitute for other composite materials in the tennis racket frame. By compression polymerization, polyamide was synthesized. The functionalization of Multi-walled carbon nanotube (MWCNT) was achieved using sulfuric acid and nitric acid, followed by ultrasonic preparation of nanocomposite materials with weight percentages of 5, 10, and 15. Fourier transform infrared (FTIR) and Nuclear magnetic resonance (NMR) confirmed a synthesized nanocomposite structure. Nanocomposites were tested for thermal resistance using the simultaneous thermal analysis (DTA-TG) method. scanning electron microscopy (SEM) analysis was used to determine pores' size, structure, and surface area. An X-ray diffraction analysis (XRD) analysis was used to determine their amorphous nature.