• Nuclear Engineering and Technology
• /
• v.53 no.5
• /
• pp.1634-1641
• /
• 2021

Exposure to gamma-rays is hazardous for humans and other living beings because of their high penetration through the materials. For this reason, shielding materials (usually lead, copper and stainless steel) are used to protect against gamma rays. This study's objective was to prepare ceramic materials for gamma radiation shielding by using different natural bentonite clays. Gamma-ray attenuation performances of the prepared shielding materials at different thicknesses were investigated and evaluated for different gamma-ray energies from different standard point gamma radiation sources (²⁵¹Am, ⁵⁷Co, ¹³⁷Cs, ⁶⁰Co, and ⁸⁸Y). The mass and linear attenuation coefficients of the prepared ceramics vary between 0.238 and 0.443 cm² g^-1 and between 0.479 and 1.06 cm^-1, respectively, depending on their thicknesses. Results showed that these materials could be prioritized because of their evidential properties of gamma radiation protection in radiation applications.

• Wind and Structures
• /
• v.32 no.5
• /
• pp.501-508
• /
• 2021

The turbine industry demands a reliable design with affordable cost. As technological advances begin to support turbines of huge sizes, and the increasing importance of wind turbines from day to day make design safety conditions more important. Wind turbines are exposed to environmental conditions that can affect their installation, durability, and operation. International Electrotechnical Commission (IEC) 61400-1 design load cases consist of analyses involving wind turbine operating conditions. This design load cases (DLC) is important for determining fatigue loads (i.e., forces and moments) that occur as a result of expected conditions throughout the life of the machine. With the help of FAST (Fatigue, Aerodynamics, Structures, and Turbulence), an open source software, the NREL 5MW land base wind turbine model was used. IEC 61400-1 wind turbine design standard procedures assessed turbine behavior and fatigue damage to the tower base of dynamic loads in different design conditions. Real characteristic wind speed distribution and multi-directional effect specific to the site were taken into consideration. The effect of these conditions on the economic service life of the turbine has been studied.

• Asia-Pacific Journal of Business
• /
• v.12 no.3
• /
• pp.101-115
• /
• 2021

Purpose - The purpose of this study was to examine the impact of packing regulations as a technical standard barrier on export trade. Design/methodology/approach - This study analyzed cases related to packing in major countries such as US, EU and so on. It is also show the example of export volume changed based on PRTS. Findings - First, the role of packaging and the reason why countries issued relevant packaging provisions were introduced. Then, the impacts of PRTS on export trade were expounded. And next, we focused on investigating some PRTS related cases in export trade and gave an example of export volume changed based on PRTS. Finally, we produced implications for business leaders to aware of the importance of PRTS in export. Research implications or Originality - This study provide PRTS information to traders. Trade pratitioners can respond to PRTS related regulations, actively develop PRTS technology, and take relavant to deal with PRTS barriers to eliminate or weaken the adverse effects of PRTS on export trade.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.12 no.3
• /
• pp.125-132
• /
• 2016

The European Telecommunication Standards Institute (ETSI) Technical Committee (TC) Reconfigurable Radio Systems (RRS) is standardizing the multi-mode Mobile Device (MD). The configuration of multi-mode MD is determined by the downloaded mobile communication standard software. In this paper, we introduce the Radio Library concept for multi-mode MD which is one of the key components of RRS standard. This paper also introduces the Standard Functional Block which is a part of Radio Library. A method for selecting efficiency SFBs for multi-mode MD is presented and a Radio Library is generated based on the selected SFBs. This paper also shows sample Standard Functional Block Set which included in Radio Library. In order to verify the compatibility of the generated Radio Library which was made by C language, we implement the LTE Rel-10 and Wi-Fi(802.11b) to show the efficiency of generating a mobile communication standard software based on the Radio Library. Then using the Prograph Visual Programming MartenTM 1.6.4, we compiled our LTE Rel-10 and Wi-Fi(802.11b) source code.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.10a
• /
• pp.427-429
• /
• 2015

Standard missile, which is operated by our navy force by loading on DDH-II and DDG, is representative interceptors of U.S. Navy. To defend from rapidly increased air threats after World War II, U.S. Navy had accelerated the development of interceptors, and consequently 3Ts series(Tartar, Talos, Terrier) were developed. Since Standard Missile(SM) series were developed on the back of 3Ts, SM series has been positioned as main surface-to-air interceptors. In this paper, types and technical characteristics of Standard Missile Series from SM-1 to SM-6 are investigated and described.

• Journal of the Korea Concrete Institute
• /
• v.29 no.4
• /
• pp.353-360
• /
• 2017

The objective of this study is theoretical and empirical evaluation of the flexural performance of concrete filled pretensioned spun high strength concrete pile with ring type composite shear connectors (CFP pile). The specimens are comprised of standard CFP pile, PHC pile+composite shear connector+filed concrete (CFP-N-N), standard CFP pile with $1^{st}$ reinforcements (H13-8ea), and standard CFP pile with $1^{st}$ and $2^{nd}$ reinforcements(H19-8ea). Flexural performance evaluation results showed that the ductility is improved with increased steel ratio, which leads to the increased maximum load by 46.4% (with $1^{st}$ reinforcement) and 103.9% (with $1^{st}$ and $2^{nd}$ reinforcements) compared to standard CFP ( CFP-N-N). Comparing with the predicted ultimate limit state values of the CFP pile design method and the experimental results, the design method presented in this study is reasonable since safety factor of 1.23 and 1.40 times for each reinforcement step are secured.

• Journal of Korean Neurosurgical Society
• /
• v.49 no.4
• /
• pp.212-216
• /
• 2011

Objective : It is well known that plate-to-disc distance (POD) is closely related to adjacent-level ossification following anterior cervical plate placement. The study was undertaken to compare the outcomes of two different anterior cervical plating methods for degenerative cervical condition. Specifically, the new method involves making holes for plate screws first with an air drill and then choosing a plate size. The other method was standard, that is, decide on the plate size first, locate the plate on the anterior vertebral body, and then drilling the screw holes. Our hypothesis was that the new technical tip may increase POD as compared with the standard anterior cervical plating procedure. Methods : We retrospectively reviewed 49 patients who had a solid fusion after anterior cervical arthrodesis with a plate for the treatment of cervical disc degeneration. Twenty-three patients underwent the new anterior cervical plating technique (Group A) and 26 patients underwent the standard technique (Group B). POD and ratios between POD to anterior body heights (ABH) were measured using postoperative lateral radiographs. In addition, operating times and clinical results were reviewed in all cases. Results : The mean durations of follow-up were $16.42{\pm}5.99$ (Group A) and $19.83{\pm}6.71$ (Group B) months, range 12 to 35 months. Of these parameters mentioned above, cephalad POD (5.43 versus 3.46 mm, p=0.005) and cephalad POD/ABH (0.36 versus 0.23, p=0.004) were significantly greater in the Group A, whereas operation time for two segment arthrodesis (141.9 versus 170.6 minutes, p=0.047) was significantly lower in the Group A. There were no significant difference between the two groups in caudal POD (5.92 versus 5.06 mm), caudal POO/ABH (0.37 versus 0.32) and clinical results. Conclusion : The new anterior cervical plating method represents an improvement over the standard method in terms of cephalad plate-to-disc distance and operating time.

• Journal of Broadcast Engineering
• /
• v.13 no.5
• /
• pp.612-621
• /
• 2008

Due to the various constraints such as feasible size of data payload and low transmission power, no technical specifications on the voice communication are included in the Zigbee standard. In this paper, a voice coding technique for application to the IEEE 802.15.4 standard, which is the basis of Zigbee communication, is presented. Here, both high compression and good waveform recovery are essential. To meet those requirements, a multi-stage discrete wavelet transform (DWT) block and a binary coding block consisting of two different pulse-code modulations are exploited. Theoretical analysis and simulation results in an indoor wireless channel show that the voice coder with 2-stage DWT is most appropriate from the viewpoint of compression and waveform recovery. When the line-of-sight component is dominant, the voice coding scheme has good recovery capability even in the moderate signal-to-noise power ratios. Hence, it is considered that the presented scheme will be a technical reference for the future recommendation of voice communication exploiting Zigbee.

• Journal of Digital Convergence
• /
• v.17 no.3
• /
• pp.47-54
• /
• 2019

The technical standard is an important factor in the national economy, and its importance is gaining more attention due to the emergence of the convergence industry. This is an essential element for implementing fusion technology because it ensures interoperability. Since standardization activities are essential for the growth of domestic SMEs, this study aims to diagnose the status of standardization activities of SMEs and to suggest policy directions accordingly. And we sought to clarify the status of the standardization activities of domestic SMEs and to draw some implications for the domestic promotion plan by examining the major promotion policies for overseas standardization successfully. As a result, it was found that the investment cost for the standard activities is burdensome, the professional manpower is needed, and the participation of SMEs is low due to the complexity of the standard technology. In addition, standardization activities have weaknesses in terms of technology protection, and SMEs tend to avoid technology disclosure. Therefore, in order to solve the difficulties of standardization of companies, it is necessary to establish cooperation system of supporting organizations. In order to promote standardization activities, it is necessary to establish legal basis necessary for technology protection.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.25 no.5
• /
• pp.406-412
• /
• 2022

Purpose: The role of endoscopic retrograde cholangiopancreatography (ERCP) in the management of hepatobiliary and pancreatic diseases in the pediatric population was not well defined until recently. Our aim was to determine the feasibility, outcomes, and safety of ERCP in a local pediatric population, particularly using standard adult endoscopes and accessories. Methods: This retrospective study was conducted at the National Hospital of Sri Lanka. Pediatric patients (aged <16 years) who underwent ERCP from January 2015 to December 2020 were included in the study. Data, including patient demographics, indications for the procedure, technical details, and associated complications, were collected from the internal database and patient records maintained at the hospital. Results: The study included 62 patients who underwent a total of 98 ERCP procedures. All the procedures were performed by adult gastroenterologists using standard adult endoscopes and accessories. The mean age was 11.01±3.47 years. Pancreatic diseases were the major indications for most of the procedures (n=81, 82.7%), with chronic pancreatitis being the most common. Seventeen procedures (17.3%) were carried out for biliary diseases. Overall cannulation and technical success rates were 87.8% and 85.7%, respectively. Stent placement was the most common therapeutic intervention (n=66; 67.4%). Post-ERCP pancreatitis was the most common complication, occurring in eight patients (8.2%). Conclusion: ERCP can be successfully and safely performed in pediatric populations using standard adult endoscopes and accessories with complications similar to those of adults. Adult ERCP services can be offered to most pediatric patients without additional costs of pediatric endoscopes and accessories.