• Computers and Concrete
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• v.31 no.6
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• pp.513-525
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• 2023

This research presents the experimental and theoretical evaluations on circular steel-fiber-reinforced-concrete (SFRC) columns reinforced by glass-fiber-reinforced-polymer (GFRP) rebar under the axial compressive loading. Test programs were designed to investigate and compare the effect of different parameters on the structural behavior of columns by performing tests. Theses variables included conventional concrete (CC), fiber concrete (FC), steel/GFRP longitudinal rebars, and transversal rebars configurations. A total of 16 specimens were constructed and categorized into four groups in terms of different rebar-concrete configurations, including GFRP-rebar-reinforced-CC columns (GRCC), GFRP-rebar-reinforced-FC columns (GRFC), steel-rebar-reinforced-CC columns (SRCC) and steel-rebar- reinforced-FC columns (SRFC). Experimental observations displayed that failure modes and cracking patterns of four groups of columns were similar, especially in pre-peak branches of load-deflection curves. Although the average ultimate axial load of columns with longitudinal GFRP rebars was obtained by 17.9% less than the average ultimate axial load of columns with longitudinal steel rebars, the average axial ductility index (DI) of them was gained by 10.2% higher than their counterpart columns. Adding steel fibers (SFs) into concrete led to the increases of 7.7% and 6.7% of the axial peak load and the DI of columns than their counterpart columns with CC. The volumetric ratio had greater efficiency on peak loads and DIs of columns than the type of transversal reinforcement. A simple analytical equation was proposed to predict the axial compressive capacity of columns by considering the axial involvement of longitudinal GFRP rebars, volumetric ratio, and steel spiral/hoop rebar. There was a good correlation between test results and predictions of the proposed equation.

• Journal of Dental Anesthesia and Pain Medicine
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• v.23 no.6
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• pp.327-335
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• 2023

Background: Pain control is a crucial aspect of pediatric dentistry for patient management. Thermo-mechanical devices (Buzzy^TM Pain Care Labs, USA) work on the concept of vibration and cooling and have shown promising results in pain control during local anesthesia in pediatric dentistry. On the other hand, audio distraction has also been used for pain management. The amount of pain endured is determined by the patient's perception and attentiveness. Thus, if audio function is added to the thermomechanical device it might increase its efficiency. Hence, the present study aimed to compare pain on injection using a thermo-mechanical device with and without audio during inferior alveolar nerve block (IANB) injection in children aged 5-10 years old. Methods: Twenty-eight children aged between 5 and 10 indicated for IANB were included in this randomized study. Children who were undergoing the dental procedure were divided into 2 groups, with 14 children in each group. The study group was the thermo-mechanical device with audio distraction; the control group was the thermo-mechanical device without audio distraction. IANB was administered. Subjective pain evaluation was performed using the Wong-Baker Faces Pain Rating Scale (WBFPR) and objective pain evaluation was done using the Faces, Leg, Activity, Consolability, Cry (FLACC) scale. Results: The outcome depicted a significant reduction in pain on injection for both objective and subjective evaluations in the thermo-mechanical device with an audio distraction group. Conclusions: Less pain on injection was observed, when a thermo-mechanical device was used with audio distraction for IANB procedures.

• Journal of the Korean institute of surface engineering
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• v.56 no.6
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• pp.437-442
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• 2023

This research aims to enhance the efficiency of Pt/C catalysts due to the limited availability and high cost of platinum in contemporary fuel cell catalysts. Nano-sized platinum particles were distributed onto a carbon-based support via the polyol process, utilizing the metal precursor H₂PtCl₆·6H₂O. Key parameters such as pH, temperature, and RPM were carefully regulated. The findings revealed variations in the particle size, distribution, and dispersion of nano-sized Pt particles, influenced by temperature and pH. Following sodium hydroxide treatment, heat treatment procedures were systematically executed at diverse temperatures, specifically 120, 140, and 160 ℃. Notably, the thermal treatment at 140 ℃ facilitated the production of Pt/C catalysts characterized by the smallest platinum particle size, measuring at 1.49 nm. Comparative evaluations between the commercially available Pt/C catalysts and those synthesized in this study were meticulously conducted through cyclic voltammetry, X-ray diffraction (XRD), and field-emission scanning electron microscopy-energy dispersive X-ray spectroscopy (FE-SEM EDS) methodologies. The catalyst synthesized at 160 ℃ demonstrated superior electrochemical performance; however, it is imperative to underscore the necessity for further optimization studies to refine its efficacy.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.20 no.1
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• pp.1-6
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• 2024

Crud is a corrosion deposit that forms in equipments and piping of nuclear reactor's primary systems. When crud circulates through the reactor's primary system coolant and adheres to the surface of the nuclear fuel cladding tube, it can lead to the Axial Offset Anomaly (AOA) phenomenon. This occurrence is known to potentially reduce the output of a nuclear power plant or to necessitate an early shutdown. Consequently, worldwide nuclear power plants have employed ultrasonic cleaning methods since 2000 to mitigate crud deposition, ensuring stable operation and economic efficiency. This paper details the system configuration of ultrasonic nuclear fuel cleaning equipment, outlining the function of each component. The objective is to contribute to the local domestic production of ultrasonic nuclear fuel cleaning equipment. Additionally, the paper introduces a method for accurately measuring the weight of removed crud, a crucial factor in assessing cleaning effectiveness and providing input data for the BOA code used in core safety evaluations. Accurate measurement of highly radioactive filters containing crud is essential, and weighing them underwater is a common practice. However, the buoyancy effect during underwater weighing may lead to an overestimation of the collected crud's weight. To address this issue, the paper proposes a formula correcting for buoyancy errors, enhancing measurement accuracy. This improved weight measurement method, accounting for buoyancy effects in water, is expected to facilitate the quantitative assessment of filter weights generated during chemical decontamination and system operations in nuclear power plants.

• Computers and Concrete
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• v.33 no.4
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• pp.341-348
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• 2024

Ultra-high-performance concrete (UHPC) has received remarkable attentions in civil infrastructure due to its unique mechanical characteristics and durability. UHPC gains increasingly dominant in essential structural elements, while its unique properties pose challenges for traditional inspection methods, as damage may not always manifest visibly on the surface. As such, the need for robust inspection techniques for detecting cracks in UHPC members has become imperative as traditional methods often fall short in providing comprehensive and timely evaluations. In the era of artificial intelligence, computer vision has gained considerable interest as a powerful tool to enhance infrastructure condition assessment with image and video data collected from sensors, cameras, and unmanned aerial vehicles. This paper presents a computer vision-based approach employing deep learning to detect cracks in UHPC beams, with the aim of addressing the inherent limitations of traditional inspection methods. This work leverages computer vision to discern intricate patterns and anomalies. Particularly, a convolutional neural network architecture employing transfer learning is adopted to identify the presence of cracks in the beams. The proposed approach is evaluated with image data collected from full-scale experiments conducted on UHPC beams subjected to flexural and shear loadings. The results of this study indicate the applicability of computer vision and deep learning as intelligent methods to detect major and minor cracks and recognize various damage mechanisms in UHPC members with better efficiency compared to conventional monitoring methods. Findings from this work pave the way for the development of autonomous infrastructure health monitoring and condition assessment, ensuring early detection in response to evolving structural challenges. By leveraging computer vision, this paper contributes to usher in a new era of effectiveness in autonomous crack detection, enhancing the resilience and sustainability of UHPC civil infrastructure.

• Asian Journal of Turfgrass Science
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• v.23 no.1
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• pp.9-22
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• 2009

Due to increasing concerns over issues with both water quantity and quality for turfgrass use, research was conducted to determine the response of five warm-season turfgrasses to deficit irrigation and to gain a better understanding of relative drought tolerance. St. Augustinegrass(Stenotaphrum secundatum [Walt.] Kuntze.) cultivars 'Floratam' and 'Palmetto', 'SeaIsle 1' seashore Paspalum(Paspalum vaginatumSwartz.), 'Empire' zoysiagrass(Zoysia japonica Steud.), and 'Pensacola' bahiagrass(Paspalum notatum Flugge) were established in lysimeters in the University of Florida Envirotron greenhouse facility in Gainesville. Irrigation was applied at100%, 80%, 60%, or 40% of evapotranspiration(ET). Evaluations included: a) shoot quality, leaf rolling, leaf firing; b) leaf relative water content(RWC), soil moisture content, chlorophyll content index(CCI), canopy photosynthesis(PS); c) multispectral reflectance(MSR); d) root distribution; and e) water use efficiency. Grasses irrigated at 100% and 80% of ET had no differences in visual quality, leaf rolling, leaf firing, RWC, CCI, and PS. Grasses irrigated at 60% of ET had higher values in physiological aspects than grasses irrigated at 40% of ET. 'Sealsle 1' and 'Palmetto' had a deeper root system than 'Empire' and 'Pensacola', while 'Floratam' had the least amount of root mass. Photosynthesis was positively correlated with visual assessments such as turf quality, leaf rolling, leaf firing, and sensor-based measurements such as CCI, soil moisture, and MSR. Reducing the amount of applied water by 20% did not reduce turfgrass quality and maintained acceptable physiological functioning.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.6
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• pp.807-815
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• 2015

The present study aimed at evaluating the intensity of Tifton 85 conditioning using a mower conditioner with free-swinging flail fingers and storage times on dehydration curve, fungi presence, nutritional value and in vitro digestibility of Tifton 85 bermudagrass hay dry matter (DM). The dehydration curve was determined in the whole plant for ten times until the baling. The zero time corresponded to the plant before cutting, which occurred at 11:00 and the other collections were carried out at 8:00, 10:00, 14:00, and 16:00. The experimental design was randomised blocks with two intensities of conditioning (high and low) and ten sampling times, with five replications. The high and low intensities related to adjusting the deflector plate of the free iron fingers (8 and 18 cm). In order to determine gas exchanges during Tifton 85 bermudagrass dehydration, there were evaluations of mature leaves, which were placed in the upper middle third of each branch before the cutting, at every hour for 4 hours. A portable gas analyser was used by an infrared IRGA (6400xt). The analysed variables were photosynthesis (A), stomatal conductance (gs), internal $CO_2$ concentration (Ci), transpiration (T), water use efficiency (WUE), and intrinsic water use efficiency (WUEi). In the second part of this study, the nutritional value of Tifton 85 hay was evaluated, so randomised blocks were designed in a split plot through time, with two treatments placed in the following plots: high and low intensity of cutting and five different time points as subplots: cutting (additional treatment), baling and after 30, 60, and 90 days of storage. Subsequently, fungi that were in green plants as well as hay were determined and samples were collected from the grass at the cutting period, during baling, and after 30, 60, and 90 days of storage. It was observed that Tifton 85 bermudagrass dehydration occurred within 49 hours, so this was considered the best time for drying hay. Gas exchanges were more intense before cutting, although after cutting they decreased until ceasing within 4 hours. The lowest values of acid detergent insoluble nitrogen were obtained with low conditioning intensity after 30 days of storage, 64.8 g/kg DM. The in vitro dry matter of Tifton 85 bermudagrass did not differ among the storage times or the conditioning intensities. There was no fungi present in the samples collected during the storage period up to 90 days after dehydration, with less than 30 colony forming units found on plate counting. The use of mower conditioners in different intensities of injury did not speed up the dehydration time of Tifton 85.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.3
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• pp.102-110
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• 2005

Piezoelectric transformers(PT) are expected to be small, thin and highly efficient, and which are attractive as a transformer with high power density for step down voltage. For these reasons, we have attempted to develop a step-down PT for the miniaturized adaptor. We propose a PT, operating in thickness extensional vibration mode for step-down voltage. This PT consists of a multi-layered construction in the thickness direction. In order to develop the step-down PT of 10 W class and turn ratio of 0.1 with high efficiency and miniaturization, the piezoelectric ceramics and PT designs are estimated with a variety of characteristics. The basic composition of piezoelectric ceramics consists of ternary yPb(Zr$_{x}$Ti$_{1-x}$)O$_{3}$-(1-y)Pb(Mn$_{1/3}$Nb1$_{1/3}$Sb$_{1/3}$)O$_{3}$. In the piezoelectric characteristics evaluations, at y=0.95 and x=0.505, the electromechanical coupling factor(K$_{p}$) is 58$\%$, piezoelectric strain constant(d$_{33}$) is 270 pC/N, mechanical quality factor(Qr$_{m}$) is 1520, permittivity($\varepsilon$/ 0) is 1500, and Curie temperature is 350 $^{\circ}C$. At y = 0.90 and x = 0.500, kp is 56$\%$, d33 is 250 pC/N, Q$_{m}$ is 1820, $\varepsilon$$_{33}$$^{T}$/$\varepsilon$$_{0}$ is 1120, and Curie temperature is 290 $^{\circ}C$. It shows the excellent properties at morphotropic phase boundary regions. PZT-PMNS ceramic may be available for high power piezoelectric devices such as PTs. The design of step-down PTs for adaptor proposes a multi-layer structure to overcome some structural defects of conventional PTs. In order to design PTs and analyze their performances, the finite element analysis and equivalent circuit analysis method are applied. The maximum peak of gain G as a first mode for thickness extensional vibration occurs near 0.85 MHz at load resistance of 10 .The peak of second mode at 1.7 MHz is 0.12 and the efficiency is 92$\%$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2621-2627
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• 2014

Directional transmission is one of key technology to solve the utmost problem that current mobile communication system faces, which is explosively increasing data traffic, since directional transmission can maximize the throughput of mobile communication systems. In this work, we consider power allocation scheme for mobile communication system which utilizing directional transmission. Especially, we consider the case in which multiple users in the same sector of base station, are served at the same time by utilizing directional transmission. For this scenarios, we consider equal power allocation scheme, Water-filling based scheme and inverse SNR scheme. Moreover, we propose beam power allocation scheme whose objective is to maximize overall system throughput by taking into account interference between different directional transmissions. Moreover, we have examined the spectral efficiency and Jain's fairness index of various power allocation schemes for directional transmission by using system level simulator that has been developed in our previous work. Through simulations, it has been verified that the proposed power allocation scheme can improve the spectral efficiency of the system by 28%.

• Journal of Korea Technology Innovation Society
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• v.12 no.4
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• pp.819-839
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• 2009

Proposed increases to the government's R&D budget should be discussed based on merits of meeting efficiency and effectiveness criteria. The evaluation of the national R&D budget and related programs are performed in two areas: a system of R&D budget coordination and allocation, and a system of R&D program performance. This paper mainly focuses on the operational areas of R&D budget evaluation system with a focus on their impact to efficiency and effectiveness. The core view point for a R&D budget evaluation system involves two directions: Firstly, to detail the relationships between the later stage (ex. post) activities such as, program survey, analysis, and program performance evaluation, with the budget evaluation. Secondly, to critically oversee all R&D coordination procedures with a different perspective. Budgeting is generally known as a serial process of policy making, planning and executing. It is highly desirable for the budget to be allocated to, and spent by, specific programs as planned, and that each plan be aligned with a specific policy. As such, a strong relevance between the program structure and budget code system is integral to successful execution. It should be performed using a decision making system which closely examines the link between policy and budget. It is also recommended that systematic relationships be maintained among budget coordination and allocation, performance evaluations of policy and program levels, and program survey and analysis system, and that their operational schedule should be reviewed comprehensively as a one integrated system. The National Science and Technology Council is expected to play a major and practical role as the center of policy planning and should be supported by the objective and unbiased system which covers overall process from policy making to program evaluation. Finally, increased utilization of contents, timely program survey and analysis, and accurate of activity scheduling of budget coordination and allocation, and diligent program performance evaluation all contribute towards a more efficient and effective overall evaluation system.