• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2059-2063
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• 2008

When a thermocouple is placed in a high temperature gas-flow stream, the measured temperature could be biased from the true gas temperature due to a large radiation heat loss from a thermocouple surface to its surroundings. In this study, two thermocouples of unequal diameters with 1/8 inch and 1/16 inch are used to correct the radiation effect. The method is called the reduced radiation error (RRE). The preliminary test results show that the radiation and the sheath conduction cannot be negligible for the gas temperature measurement. To minimize the sheath conduction effect, all the thermocouples will have a grounded junction and 1/8 inch thermocouple will be replaced with 1 mm thermocouples. In addition, the computational fluid dynamics code analysis shows that there is a negligible temperature difference between the positions where the thermocouples were installed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.1
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• pp.22-28
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• 2012

While a dash panel component, close to passengers, plays a very important role to protect heat and noise from a power train, it is also a main path that transfers vibration energy and eventually radiates acoustic noise into the cavity. Therefore, it is important to provide optimal design schemes incorporating sound packages such as a dash isolation pad and a floor carpet, as well as structures. The present study is the extension of the previous investigation how design variables affect sound radiation, which was carried out using the simple plate and framed system. A novel FE-SEA hybrid simulation model is used for this study. The system taken into account is a dash panel component of a sedan vehicle, which includes front pillars, front side members, a dash panel and corresponding sound packages. Design variables such as panel thicknesses and sound packages are investigated how they are related to two main NVH indexes, sound radiation power(i.e. structure-borne) and sound transmission loss(i.e. air borne). In the viewpoint of obtaining better NVH performance, it is shown that these two indexes do not always result in same tendencies of improvement, which suggests that they should be dealt with independently and are also dependent on frequency regions.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.1
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• pp.35-41
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• 2008

The radiative heat loss from a receiver of a dish solar collector is numerically investigated. The dish solar collector considered in this paper consists of a receiver and multi-faceted mirrors. In order to investigate the performance comparison of dish solar collectors, six different mirror arrays and four different receivers are considered. A parabolic- shaped perfect mirror of which diameter is 1.40 m is considered as the reference for the mirror arrays. The other mirror arrays which consist of twelve identical parabolic-shaped mirror facets of which diameter are 0.405 m are suggested for comparison. Their reflecting areas, which are 1.545 $m^{2}$, are the same. Four different receiver shapes are a conical, a dome, a cylindrical, and a unicorn type. The radiative properties of the mirror surfaces and the receiver surfaces may vary the thermal performance of the dish solar collector so that various surface properties are considered. In order to calculate the radiative heat loss in the receiver, two kinds of methods are used. The Net Radiation Method that is based on the radiation heat balance on the surface is used to calculate the radiation heat transfer rate from the inside surface of the receiver to the environment. The Monte-Carlo Method that is the statistical approach is adopted to predict the radiation heat transfer rate from the reflector to the receiver. The collector efficiency is defined as the results of the optical efficiency and the receiver efficiency. Based on the calculation, the unicorn type has the best performance in receiver shapes and the STAR has the best performance in mirror arrays except the perfect mirror.

• Journal of Photoscience
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• v.9 no.2
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• pp.466-469
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• 2002

An experiment has been conducted to measure the impact of UV radiation sensitivity on dermatophytes (Microsporum boullardii) by different UV radiation exposure time interval (1 min, 2 min 5 min, 10 min and 20 min) in degradation of keratin (Feather) in growth promoting substances of protein, cysteine, cystine and methionine from 7 to 28 days of incubation period. Mutant strain caused maximum weight loss with 1 minutes of UV radiation exposure at 21 day and mutant strain became immune in sensitivity at 14 days for decomposition of feathers. Maximum protein caused at 21st days with 20 minutes U.V radiation exposure and immune sensitivity had deducted with other UV radiation exposure time. On 28 days, mutant strains became immune with all exposure times, Whereas maximum methionine caused at 21st days with 20 minutes UV radiation exposure. Maximum cysteine caused at $14^{th}$ day with 5 minutes UV radiation exposure and mutant strain showed immune response at all time periods. Cystine production was also followed by cysteine at 21 day and also showed complete immune response with 1 and 2 minutes UV radiation exposure at7 and 14 days. Thus mutant strain of Microspornm boullardii can be used as a biotechnological tool for production of growth promoting substances.

• Radiation Oncology Journal
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• v.30 no.3
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• pp.132-139
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• 2012

Purpose: The purpose of this prospective multi-institutional study was to evaluate the nutritional status of patients undergoing radiotherapy (RT) for treatment of head and neck, lung, or gastrointestinal cancer. Materials and Methods: A total of 1,000 patients were enrolled in this study at seven different hospitals in Seoul, Korea between October 2009 and May 2010. The nutritional status of patients after receiving 3 weeks of RT was evaluated using subjective global assessment (SGA). The nutritional status of each patient was rated as well nourished (A), moderately malnourished (B), or severely malnourished (C). Results: The mean age of patients in this study was $59.4{\pm}11.9$ years, and the male to female ratio was 7:3. According to the SGA results, 60.8%, 34.5%, and 4.7% of patients were classified as A, B, or C, respectively. The following criteria were significantly associated with malnutrition (SGA B or C; p < 0.001): loss of subcutaneous fat or muscle wasting (odds ratio [OR], 11.473); increased metabolic demand/stress (OR, 8.688); ankle, sacral edema, or ascites (OR, 3.234); and weight loss ${\geq}5%$ (OR, 2.299). Conclusion: SGA was applied successfully to assess the nutritional status of most patients. The prevalence of malnutrition in a radiation oncology department was 39.2%. The results of this study serve as a basis for implementation of nutrition intervention to patients being treated at radiation oncology departments.

• Steel and Composite Structures
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• v.50 no.3
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• pp.299-318
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• 2024

The main objective of this paper is to compute the far-field acoustic radiation (sound radiation) of functionally graded plates (FGM) loaded by sinusoidally varying point load subjected to the arbitrary boundary condition is carried out. The governing differential equations for thin functionally graded plates (FGM) are derived using classical plate theory (CPT) and Rayleigh integral using the elemental radiator approach. Four cases, segregated on power-law index k=0,1,5,10, are studied. A novel approach is illustrated to compute sound fields of vibrating FGM plates using the physical neutral surface with an elemental radiator approach. The material properties of the FGM plate for all cases are calculated considering the power law indexes. An in-house MATLAB code is written to compute the natural frequencies, normal surface velocities, and sound radiation fields are analytically calculated using semi-analytical formulation. Ansys is used to validate the computed sound power level. The parametric effects of the power law index, modulus ratios, different constituent of FGM plates, boundary conditions, damping loss factor on the sound power level, and radiation efficiency is illustrated. This work is the benchmark approach that clearly explains how to calculate acoustic fields using a solid layered FGM model in ANSYS ACT. It shows that it is possible to asymptotically stabilize the structure by controlling the intermittent layers' stiffness. It is found that sound fields radiated by the elemental radiators approach in MATLAB, ANSYS and literatures are in good agreement. The main novelty of this research is that the FGM plate is analyzed in the low-frequency range, where the stiffness-controlled region governs the whole analysis. It is concluded that a clamped mono-ceramic FGM plate radiates a lesser sound power level and higher radiation efficiency than a mono-metallic or metal-rich FGM plate due to higher stiffness. It is found that change in damping loss factor does not affect the same constituents of FGM plates but has significant effects on the different constituents of FGM plates.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.5
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• pp.549-556
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• 2015

In this paper, design and fabrication for inset fed microstrip patch antennas applied to the $3{\times}3$ array CSLR and eight CSLR, respectively, to the ground plane are studied. The theoretical results are compared to the experimental results for the return loss and radiation pattern. For 'CSLR 09' antenna, the theoretical result for the resonant frequency and the return loss are 2.82 GHz and - 25.35 dB, respectively. The experimental results are obtained for a 2.885 GHz, -30.72 dB. Theoretical results for the resonant frequency and the return loss of the 'CSLR 08' antenna are 2.82 GHz, -16.77 dB, respectively, and the experimental results are obtained for a 2.885 GHz, -14.90 dB. In addition, E-plane and H-plane radiation patterns in comparison with designed and fabricated antennas are in good agreement.

• The Journal of the Acoustical Society of Korea
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• v.4 no.2
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• pp.3-12
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• 1985

The surface intensity method is a relatively new tool which can identify the noise source or path and measure the radiation power. One microphone and one accelerometer are used in this new technique. In this study, this new technique has been used to measure the field transmission loss trough doors. The results of the experiment indicate that the surface intensity method produces reliable data and can be applied to the transmission loss measurement.

• The Journal of the Acoustical Society of Korea
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• v.4 no.2
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• pp.3.1-3.1
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• 1985

The surface intensity method is a relatively new tool which can identify the noise source or path and measure the radiation power. One microphone and one accelerometer are used in this new technique. In this study, this new technique has been used to measure the field transmission loss trough doors. The results of the experiment indicate that the surface intensity method produces reliable data and can be applied to the transmission loss measurement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.54-62
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• 2016

The most efficient system for converting heat to electricity, AMTEC (Alkali Metal Thermal-to-Electric Convertor), is a device that directly converts heat energy to electricity using an alkali metal (sodium) as the working fluid. The AMTEC consists of a low pressure chamber, high pressure chamber, BASE (Beta-Alumina Solid Electrolyte), and artery wick. The main heat loss of the AMTEC system occurs in the low pressure chamber. A high power generation rate is thought to be obtainable by using a high temperature in the BASE. Therefore, to reduce the radiation heat loss, 6 types of radiation shields were examined to reduce the radiative heat loss in the low pressure chamber. The power generation rate of the AMTEC varied depending on the shape of the radiation shield. CFD (Computational Fluid Dynamics) analyses were carried out to optimize the shape of the radiation shield. As a result, the optimum radiation shield was found to consist of a curvature formed at the vertical point, in which case the dimensionless temperature (condenser temperature/BASE temperature) is approximately 0.665 and the maximum power generated is calculated to be 17.69W. Increasing the distance beween the BASE and condenser leads to an increase in the power generated, and the power generated with the longest distance was 17.58 W. The shields with multiple holes and multiple horizontal layers showed power reduction rates of 0.91 W and 2.06 W, respectively.