• Advances in Energy Research
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• v.4 no.3
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• pp.189-202
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• 2016

This work emphasized optimum production of biodiesel using non-edible Prunus armeniaca (Bitter Apricot) oil via transesterification collected from the high altitude areas of Himachal Pradesh, India. In this study the author produced biodiesel through the process of transesterification by using an alkali catalyst with alcohol (methanol and ethanol), under the varying molar ratio (1:6, 1:9, 1:12), variable catalyst percentage (1% and 2%) and temperature ($70^{\circ}C$, $75^{\circ}C$, $80^{\circ}C$, $85^{\circ}C$). Furthermore, a few strong base catalysts were used that includes sodium hydroxide, potassium hydroxide, sodium metal and freshly prepared sodium methoxide. After screening the catalyst, response surface methodology (RSM) in connection with the central composite design (CCD) was used to statistically evaluate and optimize the biodiesel production operation using NaOH as catalyst. It was found that the production of biodiesel achieved an optimum level biodiesel yield with 97.30% FAME conversion under the following reaction conditions: 1) Methanol/oil molar ratio: 1:6, 2) Reaction time: 3h, 3) Catalyst amount: NaOH 2 wt. %, and 4) Reaction temperature: $85^{\circ}C$. The experimental results showed that the optimum production and conversion of biodiesel through the process of transesterification could be achieved under an optimal set of reaction conditions. The biodiesel obtained showed appropriate fuel properties as specified in ASTM, BIS and En- standards.

• Smart Structures and Systems
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• v.6 no.5_6
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• pp.595-618
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• 2010

This paper describes the application of a wireless sensor network to a 31 meter-tall medieval tower located in the city of Trento, Italy. The effort is motivated by preservation of the integrity of a set of frescoes decorating the room on the second floor, representing one of most important International Gothic artworks in Europe. The specific application demanded development of customized hardware and software. The wireless module selected as the core platform allows reliable wireless communication at low cost with a long service life. Sensors include accelerometers, deformation gauges, and thermometers. A multi-hop data collection protocol was applied in the software to improve the system's flexibility and scalability. The system has been operating since September 2008, and in recent months the data loss ratio was estimated as less than 0.01%. The data acquired so far are in agreement with the prediction resulting a priori from the 3-dimensional FEM. Based on these data a Bayesian updating procedure is employed to real-time estimate the probability of abnormal condition states. This first period of operation demonstrated the stability and reliability of the system, and its ability to recognize any possible occurrence of abnormal conditions that could jeopardize the integrity of the frescos.

• The Journal of Sustainable Design and Educational Environment Research
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• v.17 no.3
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• pp.17-25
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• 2018

In this research, we analyze the factors considered by parents of subjects of special education when selecting special educational institutions for children, and present proposals for improving the placement plan of special subjects, The results are as follows. First, for special education subjects, a considerable number of kindergarten processes are required for compulsory education, and special education subjects are selected for elementary school entrance. Second, the factors of choosing the special educational institution of parents of special education subjects are the expertise of the teacher and the operation of the curriculum, the type and extent of child disability, the distance to school and the way of commuting, educational facilities, Treatment room etc). Thirdly, it was found that parents' choices are the largest among schools in the school area, as to how special education institutions of special education subjects are arranged. For proper placement planning, it is necessary to accurately grasp the number of subjects for special education, so the selection time of the subjects of special education shall be the process of kindergarten at the latest, the disparity of special education institutions and the disparity of educational facilities It is necessary to set school books to solve it.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.2
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• pp.127-137
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• 2019

Low-rise residential community is the most popular type (51%) of residential neighborhoods in Seoul. Currently, there is a shortage of public facilities needed for living conditions and the quality of life in low-rise residential areas. This study defines 'public facility' as infrastructure to improve the living environment and used by residents jointly in low-rise residential areas. In this regard, this study analyzes current legal and institutional standards, latest trends in public facility of apartments, and residents' demand and satisfaction level in order to find out the criteria for installation of priority public facilities. As a result, the essential facility basically conforms to the number of household which is the standard of the facility supply in apartment. However, considering the limitations on the accessibility due to low density, it should consider two standards at the same time: the number of household and distance (radius of neighborhood). In conclusion, it is necessary to install legally prescribed facilities according to the number of household and distance: 500 households facilities in 250m radius neighborhood and 1,000 households facilities in 400m radius neighborhood. Also, considering the reality of low-rise residential area, it is necessary to integrate some facilities that can be functionally linked to improve level of utility and efficiency of operation and management. It is expected that the output of this study can be applied to institutionalize of the legal basis for the public facility of low-rise residential community.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.149-154
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• 2011

In order to explore properties of various rubber compounds after thermal aging under the condition similar to the operating environment of a fuel cell-stack, heat resistance and compression set of those compounds were investigated for a long term operation in $H_2SO_4$, $H_2O$, and LLC (ethylene glycol : $H_2O=50:50$) solution. It was assumed that aging Acrylonitrile butadiene rubber (NBR) and Elthylene Propylene diene rubber (EDPM) compound in the solution resulted in discoloration as time passed. It was also found that hydrolysis was developed on the Silicone rubber (VMQ) compound intentionally aged under acidic condition by means of TGA, SEM, and EDS analysis.

• Journal of the Korean Society of Safety
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• v.37 no.3
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• pp.71-78
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• 2022

The purpose of this study is to improve the National Fire Mobilization Plan. This plan is a national-level comprehensive response system aimed to compensate for scarce firefighting resources and minimize damage from large-scale disasters that exceed the response limits of city and province firefighting forces. As such, relevant literature and domestic and foreign firefighting mobilization standards were reviewed, and simulations of firefighting mobilization were performed using the QGIS program to compare and analyze cases. Results showed that, as opposed to the current method of issuing mobilization orders by dividing resources according to city and province, recognizing the entire country as a single entity and prioritizing the mobilization of adjacent firefighting resources is more effective in terms of minimizing time and distance and more quickly securing resources. Regarding national firefighting mobilization, recognizing the country's firefighting resources as a whole will allow adjacent firefighting resources to be mobilized with priority. However, the mobilization-related limits of each region need to be set to respond to local disasters. Once the scale of mobilization is determined, a system that can quickly calculate how to mobilize firefighting resources based on location and distance can be established. Additionally, it is necessary to create an integrated management system so the central government can directly organize and mobilize local firefighting resources.

• Journal of IKEEE
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• v.26 no.1
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• pp.1-9
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• 2022

In order to secure the reliability of the power system and to increase the penetration level of distributed energy resources (DERs), requirements such as IEEE 1547 have been revised to strengthen the grid connection standards for DER. This paper proposes a control scheme for smart inverter functions based on IEEE 1547-2018 that satisfy these standards, and introduces a power HILS-based test platform built for verification of smart inverter. Among the smart inverter functions, Volt-var and Frequency-watt allow the curve to be set from the upper level to comply with the interoperability and operation time of enable signals for each function are controlled by references from the upper level. According to the requirement, Volt-var and Frequency-watt are performed via power HILS platform and verified through the measurement results that all of the specified type tests were satisfied.

• 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 Korean Society of Industrial and Systems Engineering
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• v.46 no.2
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• pp.133-142
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• 2023

The large process plant is currently implementing predictive maintenance technology to transition from the traditional Time-Based Maintenance (TBM) approach to the Condition-Based Maintenance (CBM) approach in order to improve equipment maintenance and productivity. The traditional techniques for predictive maintenance involved managing upper/lower thresholds (Set-Point) of equipment signals or identifying anomalies through control charts. Recently, with the development of techniques for big analysis, machine learning-based AAKR (Auto-Associative Kernel Regression) and deep learning-based VAE (Variation Auto-Encoder) techniques are being actively applied for predictive maintenance. However, this predictive maintenance techniques is only effective during steady-state operation of plant equipment, and it is difficult to apply them during start-up and shutdown periods when rises or falls. In addition, unlike processes such as nuclear and thermal power plants, which operate for hundreds of days after a single start-up, because the pumped power plant involves repeated start-ups and shutdowns 4-5 times a day, it is needed the prediction and alarm algorithm suitable for its characteristics. In this study, we aim to propose an approach to apply the optimal predictive alarm algorithm that is suitable for the characteristics of Pumped Storage Power Plant(PSPP) facilities to the system by analyzing the predictive maintenance techniques used in existing nuclear and coal power plants.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.50 no.2
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• pp.86-93
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• 2024

Objectives: Orthognathic surgery is a surgical procedure performed by intraoral approach with established and safe techniques; however, excessive blood loss has been reported in rare cases. In response, investigative efforts to identify methods to reduce the amount of blood loss have been made. Among such methods, the administration of tranexamic acid was reported to reduce the amount of intraoperative blood loss. However, few studies to date have reported the effect of tranexamic acid in orthognathic surgery under hypotensive anesthesia. The present study aimed to investigate the effect of the administration of tranexamic acid on intraoperative blood loss in patients undergoing bimaxillary (maxillary and mandibular) orthognathic surgery under hypotensive anesthesia. Patients and Methods: A total of 156 patients (mean age, 27.0±10.8 years) who underwent bimaxillary orthognathic surgery under hypotensive anesthesia performed by the same surgeon between June 2013 and February 2022 were included in this study. The following data were collected from the medical records of each patient: background factors (age, sex, and body mass index), use of tranexamic acid, surgical procedures, previous medical history, duration of surgery, American Society of Anesthesiology physical status findings before surgery, intraoperative blood loss as a primary outcome, in-out balance, and blood test results. Descriptive statistics were calculated for statistical analysis, and a t-test and the chi-squared test were used for between-group comparisons. Group comparisons were performed after 1:1 propensity score matching to adjust for confounding factors. Statistical significance was set at P<0.05. Results: Comparison between the groups based on the use of tranexamic acid revealed a significant difference in operation time. Propensity score matching analysis revealed that intraoperative blood loss was significantly lower in the tranexamic acid group. Conclusion: The administration of tranexamic acid was effective in reducing intraoperative blood loss in patients undergoing bimaxillary orthognathic surgery under hypotensive anesthesia.