• Journal of the Korean Society of Industry Convergence
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• v.23 no.6_2
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• pp.971-977
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• 2020

In this paper, We propose a portable electrostatic meter which can measure high voltage static electricity caused by friction to prevent fire or explosion accidents in grinding, crushing, power injection, transport, filling, dust removal, painting, and foreign matter removal processes. The proposed device not only shows static electricity strength in 4 steps with respect to distance and voltage but also gives warning with a buzzer, on process facilities that are likely to generate high voltage static electricity due to friction. The device is implemented by filtering the signal detected by the wireless antenna, amplifying the signal by 6 times, and passing the signal through the integrator circuit. Tests are carried out with an electrostatic discharge simulator. And the results show that 4 LEDs are turned on at the distance of 10cm, 3 LEDs at 12cm, 2 LEDs at 13cm, and 1 LED at 15cm, when a fixed voltage of 500V is given. And also, the tests show that the static electricity can be detected at 5cm on 100V, 10cm on 200V, 15cm on 500V, 20cm on 1000V, and 25cm on 1500V. We expect to reduce accidents caused by static electricity by allowing safety managers on fields where fire or explosion accidents can happen to monitor static electricity.

• Analytical Science and Technology
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• v.34 no.3
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• pp.128-133
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• 2021

During titration, several chemical reactions result in changes not only in the potential of chemicals, but also in the colors of the indicator. In a potentiometric titration, a titration curve is obtained by measuring the abrupt change in the potential at the endpoint. Generally, acid-base titration is performed by observing the color change caused by an indicator to determine the endpoint. The method of determining the endpoint by measuring the potential difference has been well established and commercialized; however, the devices that can obtain the endpoint by observing the color change are limited. Consequently, in this study, a simple and precise spectral endpoint detector was manufactured using a drop-counter comprising an infrared emitter and a phototransistor, a white light LED as the light source and photodetector, and an analog-to-digital converter (Arduino). Spectrator, a new named, showed excellent results in terms of the reproducibility of acid-base titration using thymol blue as an indicator. Herein, we present the results of the Spectrator-manufacturing process as well as the experimental results.

• Journal of Radiation Protection and Research
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• v.47 no.4
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• pp.214-225
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• 2022

Background: The conventional cerium-doped Gd₂Al₂Ga₃O₁₂ (GAGG(Ce)) scintillator-based gamma-ray imager has a bulky detector, which can lead to incorrect positioning of the gammaray source if the shielding against background radiation is not appropriately designed. In addition, portability is important in complex environments such as inside nuclear power plants, yet existing gamma-ray imager based on a tungsten mask tends to be weighty and therefore difficult to handle. Motivated by the need to develop a system that is not sensitive to background radiation and is portable, we changed the material of the scintillator and the coded aperture. Materials and Methods: The existing GAGG(Ce) was replaced with Bi₄Ge₃O₁₂ (BGO), a scintillator with high gamma-ray detection efficiency but low energy resolution, and replaced the tungsten (W) used in the existing coded aperture with lead (Pb). Each BGO scintillator is pixelated with 144 elements (12 × 12), and each pixel has an area of 4 mm × 4 mm and the scintillator thickness ranges from 5 to 20 mm (5, 10, and 20 mm). A coded aperture consisting of Pb with a thickness of 20 mm was applied to the BGO scintillators of all thicknesses. Results and Discussion: Spectroscopic characterization, imaging performance, and image quality evaluation revealed the 10 mm-thick BGO scintillators enabled the portable gamma-ray imager to deliver optimal performance. Although its performance is slightly inferior to that of existing GAGG(Ce)-based gamma-ray imager, the results confirmed that the manufacturing cost and the system's overall weight can be reduced. Conclusion: Despite the spectral characteristics, imaging system performance, and image quality is slightly lower than that of GAGG(Ce), the results show that BGO scintillators are preferable for gamma-ray imaging systems in terms of cost and ease of deployment, and the proposed design is well worth applying to systems intended for use in areas that do not require high precision.

• The Korean Journal of Nuclear Medicine Technology
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• v.25 no.2
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• pp.41-47
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• 2021

Purpose There are many cyclotrons compared to the land area of the Republic of Korea. Because GMP certification is required and the nuclear medicine test does not apply for insurance, the number of examinations for nuclear medicine is decreasing. Therefore, there is a high probability of early decommissioning of the cyclotron. However, we do not unusually perform the radioactivation evaluation on concrete that can be classified as radioactive waste during the decommissioning of the cyclotron. In this study, we aim to confirm the radioactivation in the concrete surface using Handheld Radionuclide Identification Devices (RIDs). Materials and Methods Because there is no cyclotron being decommissioning in the Republic of Korea, it was impossible to perform the coring of concrete for radioactivation analysis. In this study, we used the KIRAMS-13 and analyzed the concrete surface in the target direction in the cyclotron room. After setting the target direction as the center, radionuclides were measured for about five months at thirty points with vertical and horizontal intervals of 30 cm. We used the RIIDEye(Detector: NaI(Tl) detector, manufacturer: Thermo) in this study and set the measurement time per point to one day (24 hours). Results Co-60 and Cs-137 were detected in some measurement points, and we confirmed the radioactivity of Co-60 detected at the most points. As a result, we found that the radioactivity of Co-60 was high in the diagonal direction (from the lower-left direction to the upper right direction) based on the center of the target. However, we think it is impossible to apply the corresponding results to all cyclotrons because we performed the study using only one cyclotron. Conclusion In thirty measurement points, we could confirm the radioactive nuclides and the relative radioactivity using the results of portable nuclides analyzer. Therefore, we expect that we can use the portable nuclides analyzer to select the coring position of concrete during the decommissioning of the cyclotron. Also, if we secure the radioactivation data for several years, we expect to make a more accurate estimate of radioactive waste during the preparation period of decommissioning of the cyclotron.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.143-148
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• 2015

In order to design and plan a city, the importance of collecting traffic information increases. However, current method to collecting traffic information by using sensors layed on the roads is not appropriate for exceptional cases such as national highway or newly planned city area, where sensors are already not layed. To scope the cases, the traffic information is estimated from traffic information of surroundings area. This paper develops portable traffic volume measuring equipment utilizing two or radar detector, so that more useful traffic information can be obtained in any environments. Furthermore, the system allows users to be able to instantly analyze gathered data on the site. The system has been tested in the field and proved the excellences theough the field test.

• Journal of the Korea Safety Management & Science
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• v.17 no.2
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• pp.129-137
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• 2015

This study is in regard to the gas detection system and gas detection method utilizing smart phone. This study includes; 1) the sensor module attached to the smart phone to detect and measure flammable gas or toxic gas; and 2) gas detection APP which is installed inside the smart phone and recognizes the user information and location information automatically by reading RFID tag indicating the user or the location to detect gas through the contact area where RFID and blue tooth reader is installed inside of the above mentioned smart phone, and then measures the combustible gas or toxic gas by operating above mentioned sensor module and obtains the data thus measured, and above mentioned smart phone is characterized by its transmission of the above mentioned user information, location information and measured data which are obtained by above mentioned gas detecting APP to operation server via communication network. With this, reliability for the location detecting gas by the user, the result of the measurement, etc. can be secured. Furthermore, this provides the effect of preventing artificial manipulation at the time of input which is associated with the identification of the user to be measured by utilizing removable sensor module and application or the mistake resulted from wrong input by the user. In addition, by transmitting the measured data from the sensor module carrying out gas detection to operation server, this provides the effect of making it possible to process the data thus collected to a specialized data for combustible gas or toxic gas.

• Journal of Radiation Protection and Research
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• v.47 no.1
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• pp.30-38
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• 2022

Background: Residential areas have some factors on the external exposure of residents, who usually spend a long time in these areas. Although various survey has been carried out by the government or the research institutions after the Fukushima Daiichi Nuclear Power Plant accident, the mechanism of radiocesium inventory in the terrestrial zone has not been cleared. To better evaluate the radiation environment, this study investigated the temporal changes in air dose rate and ¹³⁷Cs inventories (Bq/m²) in residential areas and agricultural fields. Materials and Methods: Air dose rate and ¹³⁷Cs inventories were investigated in residential areas located in an evacuation zone at 5-8 km from the Fukushima Daiichi Nuclear Power Plant. From December 2014 to September 2018, the air dose rate distribution was investigated through a walking survey (backpack survey), which was conducted by operators carrying a γ-ray detector on their backs. Additionally, from December 2014 to January 2021, the ¹³⁷Cs inventories on paved and permeable grounds were also measured using a portable γ-ray detector. Results and Discussion: In the areas where decontamination was not performed, the air dose rate decreased faster in residential areas than in agricultural fields. Moreover, the ¹³⁷Cs inventory on paved surfaces decreased with time owing to the horizontal wash-off, while the ¹³⁷Cs inventory on permeable surfaces decreased dramatically owing to the decontamination activities. Conclusion: These findings suggest that the horizontal wash-off of ¹³⁷Cs on paved surfaces facilitated the air dose rate decrease in residential areas to a greater extent compared with agricultural fields, in which the air dose rate decreased because of the vertical migration of ¹³⁷Cs. Results of this study can explain the faster environmental restoration in a residential environment reported by previous studies.

• Analytical Science and Technology
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• v.16 no.2
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• pp.95-101
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• 2003

In this study, water content in the mixture of methanol and ethanol was nondestructively measured by near infrared (NIR) spectroscopy. Two types of NIR instruments, portable NIR system with a photo-diode array and scanning type NIR spectrometer were used and the calibration results were compared. Partial least squares regression (PLSR) was applied for the calibration and validation for the quantitative analysis. The calibration results from both instruments showed good correlation with actual values. The calibration with the use of PLS model predicted water concentration with a standard error of prediction (SEP) of 0.10% and 0.12% for photo diode array and scanning type, respectively. During 6 days, routine analyses for 3%, 5% and 7% water in ethanol solution with 2% methanol were performed to validate the robustness of the developed calibration model. The routine analyses showed good results with coefficient of variation (CV) of within 3% for both types of NIR spectrometers. This study showed that the rapid determination of water in the mixture of methanol and ethanol was successfully performed by NIR spectroscopy and the performance of the portable NIR system with a photo diode array detector was comparable to that of the scanning type NIR spectrometer.

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.357-361
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• 2011

In this study, the liquid-crystal optical modulation X-ray detection system using a CdS which is a family of II-IV compound semiconductor was proposed. The system consist of the detector, the signal processing part, the liquid-crystal driving parts, microcontroller, and I/O parts, and was designed to be suitable for miniaturization and portable. In addition, the system can measure a wide range X-ray by using the detecting range selection. In order to evaluate the performance of the proposed system, the CdS sensor's output characteristics were confirmed in accordance with changes of dose, and excellent correlation was determined. And also, the optical penetration ratio was discussed in accordance with changes of the applied voltage by measuring the change of the liquid-crystal in accordance with changes of the applied voltage. Through these results, the characteristics of the liquid-crystal optical modulation system such as the excellent reproducibility and the noise immunity were confirmed. And we considered that the CdS cell-based liquid-crystal optical modulated portable X-ray detection system could be applied to compact, low-cost, portable system.

• Journal of IKEEE
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• v.18 no.4
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• pp.471-477
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• 2014

In this paper, we propose a low-cost license plate recognition system based on smart cam system using Android. The proposed system consists of a portable device and server. Potable device Hardware consists of ARM Cortex-A9 (S5PV210) processor control unit, a power supply device, wired and wireless communication, input/output unit. We develope Linux kernel and dedicated device driver for WiFi module and camera. The license plate recognition algorithm is consisted of setting candidate plates areas with canny edge detector, extracting license plate number with Labeling, recognizing with template matching, etc. The number that is recognized by the device is transmitted to the remote server via the user mobile phone, and the server re-transfer the vehicle information in the database to the portable device. To verify the utility of the proposed system, user photographs the license plate of any vehicle in the natural environment. Confirming the recognition result, the recognition rate was 95%. The proposed system was suitable for low cost portable license plate recognition device, it enabled the stability of the system when used long time by using the Android operating system.