• Nuclear Engineering and Technology
• /
• v.36 no.2
• /
• pp.153-164
• /
• 2004

A computational fluid dynamics (CFD) analysis has been performed to investigate the turbulent flow and heat transfer in a triangular rod bundle with pitch-to-diameter ratios (P/D) of 1.06 and 1.12. Anisotropic turbulence models predicted the turbulence-driven secondary flow in a triangular subchannel and the distributions of the time mean velocity and temperature, showing a significantly improved agreement with the measurements from the linear standard $k-{\epsilon}$ model. The anisotropic turbulence models predicted the turbulence structure for a rod bundle with a large P/D fairly well, but could not predict the very high turbulent intensity of the azimuthal velocity observed in the narrow flow region (gap) for a rod bundle with a small P/D.

• Journal of Sensor Science and Technology
• /
• v.1 no.1
• /
• pp.77-83
• /
• 1992

A primary standard of ac current at low frequency is derived from the standard of dc current by ac-dc transfer instrument. A set of 15 thermal current converters(TCCs) have been constructed as the primary current standards from 5 mA to 20 A at the frequency range of 10 Hz to 100 kHz. It is evaluated that the uncertainties for the maintenance and dissemination of ac current standard are less than 52 ppm up to 20 mA and 20 kHz, 60 ppm up to 100 mA and 20 kHz, and rising to 200 ppm at higher currents and frequencies.

• Journal of Sensor Science and Technology
• /
• v.30 no.5
• /
• pp.349-356
• /
• 2021

The Korea Research Institute of Standards and Science (KRISS), a National Metrology Institute of Korea, participated in the second-round of the international key comparison CCT-K7.2021 of triple point of water (TPW) cells. For the key comparison, three TPW cells, one of which had been used in the old CCT-K7 comparison, were assigned as the national standard of the TPW. The temperature difference (ΔT) between the average of the new and old national standards and ΔT between the new national standard and the transfer standard were measured. The comparison between the new and old national standards indicated a temperature increase of 69.5 µK after both the standards were corrected for the isotopic composition. The uncertainty of the national standard of the TPW temperature was 28 µK, and the uncertainty of ΔT was 14 µK. Three aspects of improvements in the new comparison compared to the old one were noted: (1) inclusion of two quartz cells in the national standard strengthens its long-term stability; (2) the standard deviation associated with the measurement of ΔT was reduced from 21 µK to 9.6 µK; (3) and the measured immersion profile of the TPW cells was much closer to the theoretically predicted dependence.

• Journal of the Korean Data and Information Science Society
• /
• v.16 no.4
• /
• pp.815-821
• /
• 2005

Among the various artificial neural networks the backpropagation network (BPN) has become a standard one. One of the components in a neural network is an activating function or a transfer function of which a representative function is a sigmoid. We have discovered that by updating the slope parameter of a sigmoid function simultaneous with the weights could improve performance of a BPN.

• Journal of Korean Academy of Nursing Administration
• /
• v.9 no.4
• /
• pp.571-583
• /
• 2003

Purpose: This study was aimed by presenting basic data of nurses' manpower management on studying about estimative variables and provability assumption whether it is desire or no on the transfer of nurses' duty post. Method: The study was designed retrospective survey and the subjects of this study consisted of 508 nurses who have engages in the K-university hospital. Data were analyzed by SPSS windows for 11.0, by logistic regression. Result: The status on clinical specific variables were verified on estimative variable about whether it is desire or no on the transfer of nurses' post of duty that staff nurses was 3.95 times when set the standard over the charge nurses, and unsatisfied nurses than satisfied nurses on the place of duty at present was 1.4 times. On the low domains of duty's satisfied degree was verified on predictive variable about whether it is desire or no on the transfer of nurses' post of duty that nurses of low feeling of satisfaction about personal relationship was 1.19 times, unsatisfied nurses about hospital management was 2.01 times verified on desiring transfer to other places. Conclusion: The suitability of estimative model whether it is desire or no on the transfer of nurses' post of duty explainable by the variable of the status, the feeling of satisfaction on post of duty, the personal relationship the hospital management and estimative probability was 80.9%.

• Fire Science and Engineering
• /
• v.11 no.1
• /
• pp.21-35
• /
• 1997

The natural convection and combined heat transfer induced by fire in a rectangular enclosure is numerically studied. The model for this numerical analysis is partially opened right wall. The solution procedure includes the standard k-$\varepsilon$ model for turbulent flow and the discrete ordinates method (DOM) is used for the calculation of radiative heat transfer equation. In numerical study, SIMPLE algorithm is applied for fluid flow analysis, and the investigations of combustion gas induced by fire is performed by FAST model of HAZARD I program. In this study, numerical simulation on the combined naturnal convection and radiation is carried out in a partial enclosure filled with absorbed-emitted gray media, but is not considered scattering problem. The streamlines, isothermal lines, average radiation intensity and kinetic energy are compared the results of pure convection with those of the combined convection-radiation, the combined heat transfer. Comparing the results of pure convection with those of the combined convection-radiation, the combined heat transfer analysis shows the stronger circulation than those of the pure convection. Three different locations of heat source are considered to observe the effect of heat source location on the heat transfer phenomena. As the results, the circulation and the heat transfer in the left region from heating block are much more influenced than those in the right region. It is also founded that the radiation effect cannot be neglected in analyzing the building in fire. And as the results of combustion gas analysis from FAST model, it is found that O2 concentration is decreased according to time. While CO and CO2 concentration are rapidly increased in the beginning(about 100sec), but slowly decreased from that time on.

• Journal of Korean Academy of Nursing
• /
• v.46 no.1
• /
• pp.39-49
• /
• 2016

Purpose: This study was done to develop a postural-stability patient transfer technique for care helpers in nursing homes and to evaluate its effectiveness. Methods: Four types of patient transfer techniques (Lifting towards the head board of the bed, turning to the lateral position, sitting upright on the bed, transferring from wheel chair to bed) were practiced in accordance with the following three methods; Care helpers habitually used transfer methods (Method 1), patient transfer methods according to care helper standard textbooks (Method 2), and a method developed by the author ensuring postural-stability (Method 3). The care helpers' muscle activity and four joint angles were measured. The collected data were analyzed using the program SPSS Statistic 21.0. To differentiate the muscle activity and joint angle, the Friedman test was executed and the post-hoc analysis was conducted using the Wilcoxon Signed Rank test. Results: Muscle activity was significantly lower during Method 3 compared to Methods 1 and 2. In addition, the joint angle was significantly lower for the knee and shoulder joint angle while performing Method 3 compared to Methods 1 and 2. Discussion: Findings indicate that using postural-stability patient transfer techniques can contribute to the prevention of musculoskeletal disease which care helpers suffer from due to physically demanding patient care in nursing homes.

• Journal of Korean Society of Transportation
• /
• v.27 no.5
• /
• pp.169-177
• /
• 2009

Establishing a public transportation transfer system that can reduce personal automobile use in the CBD and absorb the demand, thereby reducing congestion, is a necessity. However, the current transfer system and facilities are lacking in intermodal connectivity, require long transfer times, have complex flow patterns, and are lacking in information systems and convenience. The design analysis program of this study is to develop a program that executes computations of design analysis of transfer facilities by utilizing the existing design standards for facilities such as facilities for boarding and alighting, elements for convenience, and pedestrian facilities. Developing an analytical tool through which individual or integrated design analysis can be conducted on the design standards of various facilities is an important study for improving the work accuracy and efficiency of designing an actual transfer center.

• Journal of Sensor Science and Technology
• /
• v.30 no.2
• /
• pp.114-118
• /
• 2021

In this study, the sensitivity of an active pixel sensor (APS) was adjusted by employing a gate/body-tied (GBT) p-channel metal-oxide semiconductor field-effect transistor (PMOSFET)-type photodetector with a transfer gate. A GBT PMOSFET-type photodetector can amplify the photocurrent generated by light. Consequently, APSs that incorporate GBT PMOSFET-type photodetectors are more sensitive than those APSs that are based on p-n junctions. In this study, a transfer gate was added to the conventional GBT PMOSFET-type photodetector. Such a photodetector can adjust the sensitivity of the APS by controlling the amount of charge transmitted from the drain to the floating diffusion node according to the voltage of the transfer gate. The results obtained from conducted simulations and measurements corroborate that, the sensitivity of an APS, which incorporates a GBT PMOSFET-type photodetector with a built-in transfer gate, can be adjusted according to the voltage of the transfer gate. Furthermore, the chip was fabricated by employing the standard 0.35 ㎛ complementary metal-oxide semiconductor (CMOS) technology, and the variable sensitivity of the APS was thereby experimentally verified.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.2
• /
• pp.553-558
• /
• 2012

Purpose: This article reviews a few of the commonly used types of vascularized osseous free flaps in maxillofacial reconstruction, which still represents the gold standard of restoration. We also discuss the developing concepts in maxillofacial reconstruction. Recent findings: Most of the literature reconfirms the established patterns of reconstruction with the aid of vascularized osseous free flaps. This method of free-tissue transfer is also feasible in cases of osteoradionecrosis or bisphosphonate-related osteonecrosis of the jaw. These flaps are also suitable for prosthetic restoration using osseointegrated dental implants. Summary: Vascularized osseous free flaps still remain the standard of care. Improvements upon the free-tissue transfer method employing vascularized osseous free flaps, such as distraction osteogenesis, tissue engineering, and imaging techniques, currently require further development, but these technologies could lead to improved outcomes of maxillofacial reconstruction in the near future.