• Journal of the Korean Institute of Gas
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• v.26 no.6
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• pp.1-8
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• 2022

With the development of the chemical industry, related accidents frequently occur, and fire and explosion accidents account for a large proportion. In order to prevent fire and explosion accidents, places that handle flammable liquids are classified according to the Korean Industrial Standards (KSC IEC60079-10-1) in accordance with the relevant laws. The same applies to laboratories dealing with flammable liquids. This paper verified the applicability of the procedure for classifying explosion hazard areas according to the Korean Industrial Standards when flammable liquid release from the laboratory to form an evaporative pool, and also verified the effect of a change in ventilation speed on the release characteristics. Through this, it was found that it was difficult to apply the criteria for the classification of places at risk of explosion according to the Korean Industrial Standards, and special safety measures should be prepared.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.2
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• pp.47-59
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• 2022

Liquid hydrogen/liquid oxygen rocket engines with highest specific impulse have been developed since the 1950s and used until now to maximize the capability of space launch vehicles. Domestic liquid hydrogen infrastructures for the production, transportation and distribution are being expanded at world-class level with the rise of hydrogen economy, which is a great opportunity for the performance enhancement for indigenous space launch vehicles. In this paper, feasibility of applying liquid hydrogen as a propellant is investigated in various aspects. The status of domestic liquid hydrogen infrastructure, the technologies required for liquid hydrogen engines, and operational aspects for safe handling of hydrogen are reviewed. In addition, test facilities for developing hydrogen engines are introduced briefly.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.1
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• pp.73-77
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• 2022

The shelf life of oysters Crassostrea gigas, in two different types of packaging containers, polyethylene (PE) and polyethylene terephthalate (PET), was determined by evaluating the pH, glycogen and soluble protein content, turbidity, and viable cell count. After 7 days of storage, the pH of the packing water in the PE container decreased to 5.88, while the pH in the PET container decreased to 6.03. In the PE container, the glycogen content of the oysters decreased by 0.85 g/100 g and the soluble protein content and turbidity of the packing seawater increased by 1,927.21 mg/100 g and 3.24 McF, respectively. In the PET container, the glycogen content of the oysters decreased by 0.96 g/100 g and the soluble protein content and turbidity of the packing seawater increased by 1,674.75 mg/100 g and 0.98 McF, respectively. The reaction rate constants (K) were as follows: glycogen content, -0.18 (PE) and -0.10 (PET); soluble protein content, 0.29 (PE) and 0.26 (PET); and turbidity, 0.41 (PE) and 0.06 (PET). These results suggested that PET can be used as a new packaging container material for raw oysters because the quality is maintained and it offers more convenient handling during distribution.

• Journal of Korean Neurosurgical Society
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• v.65 no.2
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• pp.307-314
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• 2022

Objective : The percutaneous thread transection technique is a surgical dissecting method using a dissecting thread inserted through a needle under ultrasound guidance without skin incision. As the new dissecting threads were developed domestically, this cadaver study was conducted to compare the effectiveness and safety between the new threads (ultra V sswire and smartwire-01) and a pre-existing commercial dissecting thread (loop & shear) by demonstrating a modified looped thread cubital tunnel release. Methods : The percutaneous cubital tunnel release procedure was performed on 29 fresh cadaveric upper extremities. The pre-existing commercial thread was used in 5 upper extremities. The two newly developed threads were used in 24 upper extremities. Two practitioners performed the procedures separately. After the modified looped thread cubital release, anatomical and histological analyses were performed by a blinded anatomist. The presence of the dissected cubital tunnel and damaged adjacent soft tissue was assessed. Results : Out of the 29 cadaveric upper extremities, 27 specimens showed complete dissection of the Osborne ligament and the proximal fascia of the flexor carpi ulnaris muscle. One specimen was incompletely dissected in each of the ultra V sswire and smartwire-01 groups. There were no injuries of adjacent structures including the ulnar nerve, ulnar artery, medial antebrachial cutaneous nerve, or flexor tendon with either the commercial thread or the newly developed threads. The anatomical analysis revealed clear and sharp incisional margins of the cubital tunnel in the Smartwire-01 and loop & shear groups. All three kinds of threads maintained proper linear elasticity for easy handling during the procedure. The smartwire-01 provided higher visibility in ultrasound than the other threads. Conclusion : The newly developed threads were effective and safe for use in the thread cubital tunnel release procedure.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1485-1494
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• 2023

The bow of the nuclear fuel assembly is a well-known phenomenon. One of the vital criteria during the history of nuclear fuel development has been fuel assembly's mechanical stability. Once present, the fuel assembly bow can lead to safety issues like excessive water gap and power redistribution or even incomplete rod insertion (IRI). The extensive bow can result in assembly handling and loading problems. This is why the fuel assembly's bow is one of the most often controlled geometrical factors during periodic fuel inspections for VVER when compared e.g. to on-site fuel rod gap measurements or other instrumental measurements performed on-site. Our proposed screening method uses existing video records for fuel inspection. We establish video frames normalization and aggregation for the purposes of bow measurement. The whole process is done by digital image processing algorithms which analyze rotations of video frames, extract angles whose source is the fuel set torsion, and reconstruct torsion schema. This approach provides results comparable to the commonly utilized method. We tested this new approach in real operation on 19 fuel assemblies with different campaign numbers and designs, where the average deviation from other methods was less than 2 % on average. Due to the fact, that the method has not yet been validated during full scale measurements of the fuel inspection, the preliminary results stand for that we recommend this method as a complementary part of standard bow measurement procedures to increase measurement robustness, lower time consumption and preserve or increase accuracy. After completed validation it is expected that the proposed method allows standalone fuel assembly bow measurements.

• Journal of Dental Anesthesia and Pain Medicine
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• v.23 no.5
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• pp.281-285
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• 2023

Background: Dentists bend needles prior to certain injections; however, there are concerns regarding needle fracture, lumen occlusion, and sharps handling. A previous study found that a 30-gauge needle fractures after four to nine 90° bends. This fatigue life study evaluated how many 90° bends a 30-gauge dental needle will sustain before fracture when bent using a needle guide. Methods: Two operators at Element Materials Technology, an independent testing, inspection, and certification company tested 48 30-gauge needles. After applying the needle guide, the operators bent the needle to a 90° angle and expressed the anesthetic from the tip. The needle was then bent back to a 0° angle, and the functionality was tested again. This process was repeated until the anesthetic failed to pass through the end of the needle due to fracture or obstruction. Each operator tested 24 needles (12 needles from each lot), and the number of sustained bends before the needle fracture was recorded. Results: The average number of sustained bends before needle failure was 40.33 (95% confidence interval = 37.41-43.26), with a minimum of 20, median of 40, and a maximum of 54. In each trial, the lumen remained patent until the needle fractured. The difference between the operators was statistically significant (P < 0.001). No significant differences in performance between needle lots were observed (P = 0.504). Conclusion: Our results suggest that using a needle guide increases the number of sustained bends before needle fracture (P < 0.000001) than those reported in previous studies. Future studies should further evaluate the use of needle guides with other needle types across a variety of operators. Furthermore, additional opportunities lie in exploring workplace safety considerations and clinical applications of anesthetic delivery using a bent needle.

• Industry Promotion Research
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• v.8 no.4
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• pp.241-250
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• 2023

In investigating missing persons cases, the focus is on strengthening the efficiency of detectives' work in investigating missing persons cases. Disappearance cases are seen as a problem that directly affects social safety and individual well-being. The research has the following structure. The introduction presents the necessity, scope, and methodology of the study. Next, we analyze the definition, causes, types and actual conditions of disappearance cases. In terms of problems in the process of handling missing persons cases, the initial response process, problems in the response of related agencies after reporting, problems due to the prolongation of the case, and problems due to legal restrictions are analyzed. In the plan to improve the work efficiency of detectives for disappearance cases, the revitalization of public interest investigation networks, strengthening of capacity related to disappearance case investigation, professional public interest detective certification system, and establishment of exception provisions for detective activities are discussed. In the conclusion, we present what is necessary for the activities of public interest detectives specializing in missing persons cases.

• Journal of the Korean Geotechnical Society
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• v.40 no.2
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• pp.65-79
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• 2024

This study employs traditional statistical auto-regressive integrated moving average (ARIMA) and deep learning-based long short-term memory (LSTM) models to predict the deformation of earth retaining walls using inclinometer data from excavation sites. It compares the predictive capabilities of both models. The ARIMA model excels in analyzing linear patterns as time progresses, while the LSTM model is adept at handling complex nonlinear patterns and long-term dependencies in the data. This research includes preprocessing of inclinometer measurement data, performance evaluation across various data lengths and input conditions, and demonstrates that the LSTM model provides statistically significant improvements in prediction accuracy over the ARIMA model. The findings suggest that LSTM models can effectively assess the stability of retaining walls at excavation sites. Additionally, this study is expected to contribute to the development of safety monitoring systems at excavation sites and the advancement of time series prediction models.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.3
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• pp.269-274
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• 2010

Present state of nationwide marine facilities reported to Minister of Land, Transport and Maritime Affairs{MLTM} in Korea for two years 2008 and 2009 was analyzed, and management plan was proposed in this study. As of the end of 2009, total number of nationwide marine facilities was reported to be 672 and to be scattered along the coasts all over the nation. 124 marine facilities reported to Masan regional maritime affairs and port office occupied 18.5% of total nationwide number. 69 marine facilities reported to Mokpo regional office and 69 marine facilities reported to Pohang regional office occupied 10.3%, respectively. 181 marine facilities reported to Busan and Masan regional offices occupied 26.9%, meaning that about a quarter of total nationwide marine facilities concentrated in Southeastern Sea of Korea centering around Busan and Masan. 320 oil and noxious liquid substances storage facilities occupied 47.6% of total nationwide number. 11 pollutant storage facilities occupied 1.6%. 178 ship construction, repair and scrap facilities occupied 26.5%. 7 cargo handling facilities occupied 1.0%. 12 waste storage facilities occupied 1.8%. none of marine facilities for tourism, housing and restaurant were reported. 88 water intake and outlet facilities occupied 13.1%. 37 fishing spots at play occupied 5.5%. 13 other marine facilities occupied 1.9%. 6 integrated marine science base facilities occupied 0.9% of total nationwide number. The guidance and the public relation for national report system of marine facilities, the improvement of national report system and management plan, the advancement and complement of national report affairs-handling guides, and the voluntary participation in national report system and the performance of duties by the owners of marine facilities were proposed for better management plan of marine facilities.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.5
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• pp.1-12
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• 2015

Length and the number of tunnels has increased 10% annually. Tunnel construction has positive effect in nature and driving condition. However, the structure of tunnels lead to a greater probability of major accidents. For this reason, tunnel is focusing its attention on the rapid incident handling and disaster management to build a tunnel management system in recently. In this study, tunnel management system adequacy analyzed in terms of operational safety using IPA and AHP analysis. IPA analysis results using the portfolio chart, incident management factors has a large gap between important and satisfaction. Disaster management is analyzed high ranking in priority. However, incident management factors are derived first priority in AHP analysis. This study determined that the results are meaningful to practitioners in the field is determined. In addition, practitioners comments should be reflected primarily for tunnel operational safely.