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( Jae Won Byun ),( Kyung Hyun Lee ),( Ha Young Kim ),( Soon Seek Yoon ),( Ji Youl Jung1 ),( Woo Seog Jeong1 ),( Jae Ku Oem ),( Jong Soo Lim ),( Myoung Heon Lee ),( You Chan Bae ) 한국예방수의학회(구 한국수의공중보건학회) 2013 예방수의학회지 Vol.37 No.1
Nine cattle among 18 in a native Korean herd died or were euthanized within 3 days. The affected cattle showed cowshed. The pigs and dogs had been fed leftover food originating from nearby restaurants, and the cattle could presumably reach the contaminated food in the pig troughs. Necropsy revealed a few chicken bones and red pepper pieces as well as large amounts of grain and rice straw hay mixed in the rumen. Botulism type D was isolated in the ruminal contents of one of the cattle. We speculated that the outbreak was associated with the cattle incidentally eating presumably contaminated leftover food from the pig trough.
Fast-response total pressure probe for turbomachinery application
Jeong-Seek Kang,양수석 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.2
To evaluate the accurate performance and characteristics of turbomachinery, it is important to measure the unsteady flow phenomena downstream of the rotating blades. This paper presents the development of a fast-response total pressure probe for the measurement of the total pressure field at the exit of blades. The result of measurement in a one-stage axial turbine is also presented. The fast-response total pressure probe is fabricated by installing a fast-response pressure sensor in the cylindrical head of the probe. In terms of simplicity of the measurement system and data reduction method, this method is more competitive over established methods that use more than four sensors. The probe is applied to the one-stage axial turbine in order to measure the instantaneous total pressure downstream of rotor blades. The measured instantaneous signal is decomposed to obtain the blade-to-blade pressure distribution. The pressure distribution due to blade passing is clearly captured. Due to the loss generation in the casing region, the total pressure and its amplitude of fluctuation by the blade passing are lower in the shroud and hub region than in mid-span. The total pressure distribution at the exit of the rotor blade is found to be slightly different from blade to blade due to the geometric difference and the different relative positions of the rotor blades and stator vanes. The developed probe successfully measures the accurate total pressure distribution at the rotor exit, and allows the evaluation of the loss distribution and the accurate performance of turbomachinery.
Thermodynamic and Aerodynamic Meanline Analysis of Wet Compression in a Centrifugal Compressor
Jeong-Seek Kang,Bong-Jun Cha,Soo-Seok Yang 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.9
Wet compression means the injection of water droplets into the compressor of gas turbines. This method decreases the compression work and increases the turbine output by decreasing the compressor exit temperature through the evaporation of water droplets inside the compressor. Researches on wet compression, up to now, have been focused on the thermodynamic analysis of wet compression where the decrease in exit flow temperature and compression work is demonstrated. This paper provides thermodynamic and aerodynamic analysis on wet compression in a centrifugal compressor for a microturbine. The meanline dry compression performance analysis of centrifugal compressor is coupled with the thermodynamic equation of wet compression to get the meanline performance of wet compression. The most influencing parameter in the analysis is the evaporative rate of water droplets. It is found that the impeller exit flow temperature and compression work decreases as the evaporative rate increases. And the exit flow angle decreases as the evaporative rate increases.
Jeong-Seek Kang,양수석 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.2
The performance of a turbine is evaluated through a turbine rig test by measuring the torque or power generated from the test turbine using a dynamometer or torque sensor installed in the test rig. Highly precise assessment requires accurate measurement of the torque or power. However, an intrinsic difficulty exists such that not all power generated by the turbine is measured by the dynamometer or torque sensor. A small portion of power generated from the test turbine is dissipated between the test turbine and torque sensor as bearing and windage losses. The dissipated energy is called mechanical loss of test rig. Therefore, measuring the mechanical loss of the test rig is necessary for the accurate evaluation of the turbine performance. The present paper classifies mechanical loss into bearing, disk windage,and extra windage losses. Spin-down tests are performed in a 1-stage axial turbine test rig to evaluate each loss. The total mechanical loss amounts to 0.78% to 1.4% of energy generated at the turbine. Bearing loss is dominant. Mechanical loss is dependent on and increases with decreasing bearing temperature.
Development of a Performance Prediction Method for Centrifugal Compressor Channel Diffusers
Jeong-Seek Kang,Sung-Kook Cho,Shin-Hyoung Kang 대한기계학회 2002 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.16 No.8
A hybrid performance prediction method is proposed in the present study. A channel diffuser is divided into four subregions: vaneless space, semi-vaneless space, channel, and channel exit region. One-dimensional compressible core flow and boundary layer calculation of each region with an incidence loss model and empirical correlation of residuary pressure recovery coefficient of a channel predict the performance of diffusers. Three channel diffusers are designed and tested for validating the developed prediction method. The pressure distributions from an impeller exit to the channel diffuser exit are measured and discussed for various operating conditions from choke to nearly surge conditions. The strong non-uniform pressure distribution which is caused by impeller-diffuser interaction is obtained over the vaneless and semi-vaneless spaces. The predicted performance shows good agreement with the measured performance of diffusers at a design condition as well as at off-design conditions.<br/>
Genome-wide analysis of gene expression by crotonaldehyde in human umbilical vein endothelial cells
Jeong, Seong-Il,Lee, Seung-Eun,Yang, Ha-Na,Park, Cheung-Seog,Cho, Jeong-Je,Park, Yong-Seek 대한독성유전단백체학회 2011 Molecular & cellular toxicology Vol.7 No.2
Crotonaldehyde (CRA) is an ${\alpha}, {\beta}$-unsaturated aldehyde that is genotoxic, carcinogenic, and mutagenic, and forms 1,N(2)-propanodeoxyguanosine. Humans are exposed to CRA in work places, and from tobacco smoke, environmental pollution, food, and beverages. In addition, CRA is a product of endogenous lipid peroxidation, arising as a consequence of oxidative stress and electrophilic stress, which may be related to development of cardiovascular diseases. In this study, we used 24 k whole human DNA chips for identification of gene expression profiles by treatment of CRA in human umbilical vein endothelial cells (HUVECs). Among the 24,000 genes of cDNA microarrays, we identified up- and down-regulated genes that changed by more than 1.8 and 2 fold by CRA. Our data showed that CRA changed gene expression patterns at the genome-wide transcriptional level in HUVECs. And several genes showed association with cardiovascular diseases.
Development of a Performance Prediction Method for Centrifugal Compressor Channel Diffusers
Kang, Jeong-Seek,Cho, Sung-Kook,Kang, Shin-Hyoung The Korean Society of Mechanical Engineers 2002 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.16 No.8
A hybrid performance prediction method is proposed in the present study. A channel diffuser is divided into four subregions: vaneless space, semi-vaneless space, channel, and channel exit region. One-dimensional compressible core flow and boundary layer calculation of each region with an incidence loss model and empirical correlation of residuary pressure recovery coefficient of a channel predict the performance of diffusers. Three channel diffusers are designed and tested for validating the developed prediction method. The pressure distributions from an impeller exit to the channel diffuser exit are measured and discussed for various operating conditions from choke to nearly surge conditions. The strong non-uniform pressure distribution which is caused by impeller-diffuser interaction is obtained over the vaneless and semi-vaneless spaces. The predicted performance shows good agreement with the measured performance of diffusers at a design condition as well as at off-design conditions.
강정식(Jeong-Seek Kang),임병준(Byeung-Jun Lim),양재준(Jae-Jun Yang),안이기(Iee-Ki Ahn) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5
Aerodynamic rig test of a radial turbine for an auxiliary power unit(APU) was performed at a high temperature turbine test facility in Korea Aerospace Research Institute. The pressure ratio, Mach number and flow coefficient in rig test condition is same with those in engine condition. The design pressure ratio is 3.096, design test speed is 34909 rpm and the turbine inlet temperature is 160 degree C. The turbine has airfoil type nozzles and the diameter of the turbine wheel is 175.74mm. The turbine map is experimentally measured and the detailed flow at the inlet of turbine is measured. The pressure distribution in the nozzle at both hub and shroud sides and the pressure distribution along the shroud casing of the turbine wheel were measured.