• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.308.2-308
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• 1998

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.5-10
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• 2002

For fitness-for-service evaluation of high temperature plant components with defects, crack growth life must be assessed properly as indicated in the recent draft of API 579 code. Type 308 stainless steel has been widely used as a field weld material in the petrochemical industry. In this study, creep crack data of type 308 stainless steel are collected and re-analyzed using $C_t$ as a characterizing fracture parameter. A unique da/dt versus $C_t$ relationship was obtained despite of difference of creep deformation constant of the reviewed materials and specimen geometry of the tested specimens. The obtained results can be employed for crack growth life assessment and fitness-for-service evaluation for the cracks in high temperature components. It is also argued that since the effect of creep properties and other material variability on the creep crack growth behavior would be minor the obtained model may be applied for most of the 308 stainless steels.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.4
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• pp.484-491
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• 2018

Primer $Sj{\ddot{o}}gren's$ Syndrome (pSS) is an autoimmune/inflammatory illness. The platelet indices (PIs) indicate the inflammatory response and activity/severity of many diseases. A vitamin D deficiency is accompanied by the increased tendency of autoimmune diseases. This study investigated whether the vitamin D levels are related to the altered platelet indices in pSS. A total of 261 individuals were included in this analytical cross-sectional study. The laboratory data of pSS patients were evaluated and the relationship between the PIs and vitamin D status was examined. According to these findings, in patients with pSS, the vitamin D levels were lower than the healthy control group (P<0.05). The vitamin D levels were negatively associated with PDW (P=0.012), but positively correlated with PCT (P<0.001). The cut-off point was obtained with receiver operating characteristics (ROC) curves for PDW: 12.53 (AUC 0.921, sensitivity 90%, specificity 85%), for PCT; 0.29 (AUC 0.660, sensitivity 68%, specificity 55%). In multivariate linear regression analysis, the most significant parameters for the effects of PDW are the following: vitamin D (${\beta}=-0.373$; t=-2.626; sig.=0.013) and plateletcrit (${\beta}=-0.308$; t=-2.13; sig.=0.040). A vitamin D deficiency may be accompanied by changes in PIs in pSS. A higher PDW and lower PCT supports the underlying inflammation, which may be vitamin D related useful parameters to consider in approaching to pSS.

• Journal of Animal Science and Technology
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• v.62 no.6
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• pp.884-892
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• 2020

Corticosterone is known as a biological stress index in many species including birds. Feather corticosterone concentration (FCC) has increasingly been used as a measure for chronic stress status in broiler chickens. As sample preparation is the first step of analytical process, different techniques of feather matrix disruption need to be validated for obtaining better result in analysing corticosterone extraction. The current study was a validation of pulverizing the feather by bead beater (BB) and surgical scissors (SS) processing prior to corticosterone extraction in feather of broiler chickens. The type of feather processing prior to the hormone extraction may alter the final output. Thereby, finding a standard method according to laboratory facilities is pivotal. This study carried out to determine the effects of feather pulverization methods on the extraction amount of corticosterone in broiler chickens. Feathers were sampled from four weeks old Ross 308 broiler chickens (n = 12 birds). All broiler chickens were kept under the same environmental condition and had access to feed and water. Feather samples were assigned to one of the following processing methods 1) using a BB for pulverizing and 2) using a SS for chopping into tiny pieces. Each sample was duplicated into two wells during enzyme immunoassay (EIA) analysis to improve the accuracy of the obtained data. The results showed lower standard errors and constant output of FCC by using the BB method compared with the SS method. Overall comparison of FCC showed a significantly higher (p < 0.001) amount of the FCC in the BB compared with the SS. Overall, using the BB method is recommended over the SS method for feather processing due to the ability to homogenize a large number of samples simultaneously, ease of use and greater extraction of feather corticosterone.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.10
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• pp.694-701
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• 2012

The main purpose of this study is to evaluate of backwash system of hydrodynamic separator filter (HSF) with solar powered submerged pumps. It consists of a photovoltaic solar array, control electronics, battery, and two submersible pump powered by a 12 voltage DC motor. The laboratory scale study on treatable potential of micro particles using backwash HSF that was a combined with perlite filter cartridge and backwash nozzles. Since it was not easy to use actual storm water in the scaled-down hydraulic model investigations, it was necessary to reproduce ranges of particle sizes with synthetic materials. The synthesized storm runoff was made with water and addition of particles; ion exchange resin partices, silica gel particles, and commercial area manhole sediment particles. HSF was made of acryl resin with 250 mm of diameter filter chamber and overall height of 800 mm. Four case test were performed with different backwashing conditions and determined the SS removal efficiency with various surface loading rates. The operated range of surface loading rate was about 308~$1,250m^3/m^2/day$. It was found that SS removal efficiency of HSF using two submersible pumps improved by about 18% compared with HSF without backwash. Nonpoint control devices with solar water pumping systems would be useful for backwashing the filter in areas with not suppling electricity and reduce filter media exchange cost.

• Steel and Composite Structures
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• v.13 no.3
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• pp.295-308
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• 2012

This paper experimentally investigated the buckling capacity of built-up steel columns mainly, Cruciform Columns (CC) and Side-to-Side (SS) columns fabricated from two Universal Beam (UB) sections. A series of nine experimental tests comprised of three UB sections, three CC sections and three SS sections with different lengths were tested to failure to measure the ultimate axial capacity of each column section. The lengths used for each category of columns were 1.8, 2.0, and 2.2 m with slenderness ratios ranging from 39-105. The measured buckling loads of the tested specimens were compared with the predicted ultimate axial capacity using Eurocode 3, AISC LRFD, and BS 5959-1. It was observed that the failure modes of the specimens included flexural buckling, local buckling and flexural-torsional buckling. The results showed that the ultimate axial capacity of the tested cruciform and side-by-side columns were higher than the code predicted design values by up to 20%, with AISC LRFD design values being the least conservative and the Eurocode 3 design values being the most conservative. This study has concluded that cruciform column and side-to-side welded flange columns using universal beam sections are efficient built-up sections that have larger ultimate axial load capacity, larger stiffness with saving in the weight of steel used compared to its equivalent universal beam counterpart.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.9
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• pp.1-9
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• 1997

Novel class A CMOS second-generation current conveyors (CCII) using 0.6.mu.m n-well standard CMOS process for high-frequency current-mode signal processing were developed. The CCII consists of a regulated current-cell for the voltage input and a cascode current mirror for the current output. In this architecture, the two input stages are coupled by current mirrors to reduce the current input impedance. Measurements of the fabricated cCII show that the current input impedance is 308 .ohm. and the 3-dB cutoff frequency when used as a voltage amplifier extends beyond 10MHz. The linear dynamic ranges of voltage and current are from -0.5V to 1.5V and from -100.mu.A to +120.mu.A for supply voltage V$\_$DD/ = -V$\_$SS/=2.5V, respectively. The power dissipation is 2 mW and the active chip area is 0.2 * 0.2 [mm$\^$2/].

• Environmental Engineering Research
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• v.25 no.3
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• pp.299-308
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• 2020

Composting is among the most effective integrated waste management strategies used to recycle sewage sludge (SS) waste and generate a useful product. An encapsulated lifting system is a relatively new industrial-scale composting technology. The objective of this study was to evaluate the effectiveness of composting dewatered stabilized SS mixed with green waste using this new technology. The composting process was monitored by changes in the physico-chemical properties, UV-visible spectra, and fourier transform infrared (FTIR) spectra. The composting temperature was steady in the thermophilic range for 24 and 12 d in the intensive and maturation phases, respectively, which fulfilled the disinfection requirement. Moreover, the temperature increased rapidly to 76.8℃ within three days, and the thermophilic temperatures peaked twice and lasted longer than in traditional composting, which accelerated SS degradation and decreased the composting period necessary to obtain mature compost. FTIR spectroscopic analysis showed a diminished in methyl group derived from methylene C-H aliphatic groups because of organic matter degradation by microorganisms and an increased number of aromatic chains. The new technology may be a viable and sustainable alternative for SS management that converts waste into compost that is useful as a soil amendment.

• Journal of Korean Society on Water Environment
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• v.23 no.3
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• pp.303-308
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• 2007

Three types dyeing wastewater (dark, medium, light color) discharged from cotton textile dyeing with reactive dye was collected at each step of process. Each process dying wastewater was analyzed and treated by ionized gas. The analysis focused on $COD_{Cr}$, SS and color. Bleaching & scouring process wastewater has the highest $COD_{Cr}$ value in the three type dyeing wastewater. SS shows the highest value at dyeing process wastewater in dark and medium color but light color has at finishing process wastewater. The result of process wastewater treatment by ionized gas was that the ionized gas was effective in $COD_{Cr}$ removing of bleaching & scouring process and finishing process wastewater but was not good at dyeing process wastewater. From that result it is estimated that the ionized gas could not work in opening the aromatic ring and react only in aliphatic component of the molecule. Because the surfactants contained in bleaching & scouring process and finishing process wastewater have only one aromatic ring in its molecular structure, in contrast with the reactive dye compounds consist of aromatic rings great part of its molecular structure. The color almost removed in 1.5 hrs reaction time but $COD_{Cr}$ removal effiency was only 30.7% through 3hrs in 1500 mL of total dyeing wastewater treated by 10 L/min ionized gas.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.552-556
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• 2005

This study was conducted to identify the characteristics of non-point pollutants discharge in a small Rural watershed. For this purpose, the typical rural area in Gongju city was selected as a research site. Water quality and water quantity data in the stream and the precipitation of the watershed were analyzed periodically from May 1 to August 31 in 2005. Also, pollutant loads were estimated using these data. As a result, the mean concentrations of BOD, TN and TP in the stream were 3.16, 3.20, 0.236 mg/L rainy season and 0.93, 2.75, 0.058 mg/L in normal survey season respectively. The estimation of non-point pollutants discharge loads were shown that BOD was 5,154.2kg, T-N was 9,164.7kg, T-P was 308.4kg, and SS was 117,163.2kg from July to August. That means above of 90% of non-point pollutants discharge was occurred in rainy season.