• Geotechnical Engineering
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• v.11 no.2
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• pp.99-106
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• 1995

Although lots of experimental studies of coal ash have been performed to study the utilization as construction materials, the environmental characteristics of coal ash are still qestionable. In this study, fly ash is examined to be classified according to Korean Environmental Standard and analized whether the batch test results are within the toler trance limit when utilized or treated as reclamation and earth work materials. The batch tests was performed to examine pH and contaminant contents. Consequently, fly ash is classified as non hazardous industrial waste. The pH value shows a strong alkalinity than the tolerance limit, but it is implied that fly ash can be used to neutralize the acid ground. All other items except pH satisfy the tolerance limit, In addition, a small quantity of additives(cement) which used to improve the poor geotechnical properties of coal ash, could decrease the pH value into the tolerance limit as well as improve strengtIL durability and permeability. It is concluded that when coal ash is used properly, there is no enviormental harmfulness as construction materials.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.649-654
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• 2002

In order to suggest recyling and handling method of a tailing, observe it's physical and chemical properties, make an quality test of aggregates which are used a tailing and then examine a applied possibility in architectural materials. Tailing has a ununiform and many-side shape and it is organized quartz, muscovite, calcite, montmorillonite. pH is 6.86-7.28 and the result of leaching test is that Hg and Pb exceed of a standard. The specific gravity of aggregates which are used tailing is 1.95-2.23 and the absorption factor is 9-14.67%. The result of test for abrasion and crushing of aggregates which are used BFS is very excellent. The heavy metal is stabilized but a eruption property of Hg is similar to original sample.

• Journal of Soil and Groundwater Environment
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• v.8 no.2
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• pp.62-69
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• 2003

The aim of research is the evaluation of the $Cr^{6+}$ emission features of the liquid injection through emission experiments in varying conditions, based on a field-mixing ratio. The results showed that the content of $Cr^{6+}$ content in cement measured had an Ordinary Potland Cement (OPC) of 25.3 mg/kg, which constitute the largest portion among the other materials. Likewise, the emission experiment of homo-gel and sand-gel generally satisfied the standard of KSLT (Korea Standard Leaching Test) in waste of 1.5 mg/L, but in case of the standard of KSLT in soil the emission of OPC $Cr^{6+}$ of 4.85 mg/kg. These conditions is a little exceeded the criteria in the ‘Ga’ area in terms of Korea Soil Environmental Preservation Law. In addition, results generated by the mock-up injection facilities revealed that $Cr^{6+}$ emission increased as Water/Cement and injection pressure increased. At injection pressure higher than 4 kg/㎤, $Cr^{6+}$ emission exceeded the water preservation standard of 0.5 mg/L. Similarly, a pattern experiment of C $r^{6+}$ emission according to pH was conducted, in order to evaluate the $Cr^{6+}$ emission features of grout materials in leachate below pH 5 such as pH 4 acid rain or landfill. Results show that $Cr^{6+}$ emission dramatically increased in high acidic or basic state. It indicates that $Cr^{6+}$ emission will probably increase in an environment where grout materials are injected. On the other hand, concentration of leachate was determined in areas where grout materials are used. The results show that the concentration of emission in an ultra purity condition does not manifest intensity, and is affected in the OPC>MC>SC order. It means that the pollutants or $Cr^{6+}$ emission increases with decreasing concentration. As such, $Cr^{6+}$ emission will probably exceed the countermeasure criteria according to the types of gout materials. Similarly, high pressure or injection will cause increased $Cr^{6+}$ emission. Therefore, the selection of materials or mixing ratio should be considered in general as well as according to specific industries, based on the strength and pH of $Cr^{6+}$ emission.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.4
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• pp.235-242
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• 2006

The precise estimation of total and organic carbon contents in sediments is fundamental to understand the benthic environment. To test the precision and accuracy of CHN analyzer and the procedure to quantify total and organic carbon contents(using in-situ acidification with sulfurous acid($H_2SO_3$)) in the sediment, the reference material s such as Acetanilide($C_8H_9NO$), Sulfanilammide($C_6H_8N_2O_2S$), and BCSS-1(standard estuary sediment) were used. The results indicate that CHN analyzer to quantify carbon and nitrogen content has high precision(percent error=3.29%) and accuracy(relative standard deviation=1.26%). Additionally, we conducted the instrumental comparison of carbon values analyzed using CHN analyzer and Coulometeric Carbon Analyzer. Total carbon contents measured from two different instruments were highly correlated($R^2=0.9993$, n=84, p<0.0001) with a linear relationship and show no significant differences(paired t-test, p=0.0003). The organic carbon contents from two instruments also showed the similar results with a significant linear relationship($R^2=0.8867$, n=84, p<0.0001) and no significant differences(paired t-test, p<0.0001). Although it is possible to overestimate organic carbon contents for some sediment types having high inorganic carbon contents(such as calcareous ooze) due to procedural and analytical errors, analysis of organic carbon contents in sediments using CHN Analyzer and current procedures seems to provide the best estimates. Therefore, we recommend that this method can be applied to measure the carbon content in normal any sediment samples and are considered to be one of the best procedure far routine analysis of total and organic carbon.

• Investigative Magnetic Resonance Imaging
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• v.18 no.1
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• pp.52-58
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• 2014

Purpose : To establish a pH measurement system for a mouse tumor study using a clinical scanner, to develop the $^1H$ and 31P radio frequency (RF) coil system and to test pH accuracy with phantoms. Materials and Methods: The $^1H$ and the $^{31}P$ surface coils were designed to acquire signals from mouse tumors. Two coils were positioned orthogonally for geometric decoupling. The pH values of various pH phantoms were calculated using the $^1H$ decoupled $^{31}P$ MR spectrum with the Henderson-Hasselbalch equation. The calculated pH value was compared to that of a pH meter. Results: The mutual coil coupling was shown in a standard $S_{12}$. Coil coupling ($S_{12}$) were -73.0 and -62.3 dB respectively. The signal-to-noise ratio (SNR) obtained from the homogeneous phantom $^1H$ image was greater than 300. The high resolution in vivo mice images were acquired using a $^{31}P$-decoupled $^1H$ coil. The pH values calculated from the $^1H$-decoupled $^{31}P$ spectrum correlated well with the values measured by pH meter ($R^2$=0.97). Conclusion: Accurate pH values can be acquired using a $^1H$-decoupled $^{31}P$ RF coil with a clinical scanner. This two-surface coil system could be applied to other nuclear MRS or MRI.

• Journal of Preventive Medicine and Public Health
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• v.7 no.2
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• pp.327-332
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• 1974

Wells are perticularly able to be a source of water-borne infections disease in the army society. Owing to untreated drinking water, high indidence of water-borne diseases are encounted in Korea. This study was carried out to evaluate the physicochemical and bacteriological states of 298 wells in army camps around Daegu city during a year from January to November, 1974. Main findings are summerized as follows: 1. Turbidity, Colorness & odor was within normal range in all samples. 2. Reaction of pH, cnsumption of KMnO4, total hardness and chlorine ion as over almost within normal range. 3. Free Ammonia was detected to 33.2% positive, and nitrite, 45.5% positive. 4. In the bacteriological test 40.3% of all samples were over the standard limit on E. Coli. 5. In comparison of nitrate and E. Coli detection, 60.1% of nitrite was over the standard limit out of the positive cases detected E. Coli. and all of E. Coli were over the standard limit out of the positive cases of nitrite. 6. The contamination was very remarkable in the spring and summer, and very diminished in the autumn and winter.

• Journal of Veterinary Science
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• v.21 no.2
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• pp.27.1-27.10
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• 2020

The efficacies of a supraglottic airway device (SGAD) and an endotracheal tube (ETT) in cats under general anesthesia with volume-controlled ventilation (VCV) were compared. Thirty healthy cats were randomly allocated for airway control using either an SGAD or an ETT. Five tidal volumes (6, 8, 10, 12, and 14 mL/kg) were randomly tested, and respiratory rates were adjusted to achieve a minute ventilation of 100 mL/kg/min. The dose of propofol necessary to insert the SGAD or ETT, the static respiratory pressure, leakage during VCV, and end tidal CO₂ (ETCO₂) were recorded. Dosages of propofol and static respiratory measurements for the SGAD and ETT groups were compared using a t-test. The distribution of leakages and hypercapnia (ETCO₂ > 45 mmHg) were compared using Fisher's exact test. A significance level of p < 0.05 was established. No significant difference in dose of propofol was observed between the SGAD and ETT groups (7.1 ± 1.0, 7.3 ± 1.7 mg/kg; p = 0.55). Static resistance pressure of the SGAD (22.0 ± 8.1 cmH₂O/L/sec) was significantly lower than that of the ETT (36.6 ± 12.9 cmH₂O/L/sec; p < 0.01). Of the 75 trials, leakage was more frequent when using an SGAD (8 events) than when using an ETT (1 event; p = 0.03). Hypercapnia occurred more frequently with SGAD (18 events) than with ETT (3 events; p < 0.01). Although intubation with an ETT is the gold standard in small animal anesthesia, the use of an SGAD can reduce airway resistance and the work of breathing. Nonetheless, SGAD had more dead space and the tidal volume for VCV needs adjustment.

• Journal of computational fluids engineering
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• v.17 no.3
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• pp.11-17
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• 2012

In this study, aerodynamic analyses have been conducted for 4-Bladed Vertical-Axis Wind Turbine (VAWT) configuration and the results are compared with experimental data. Reynolds-averaged Navier-Stokes equation with LES turbulence model is solved for unsteady flow problems. In addition, the computation results by standard k-${\omega}$ and SST k-${\omega}$ turbulence models are also presented and compared. An experiment model of 4-Bladed VAWT model has been designed and constructed herein. Experimental tests for aerodynamic performance of the present VAWT model are practically conducted using the vehicle mounted testing system. Comparison results between the experiment and the computational fluid dynamics (CFD) analyses are presented in order to show the accuracy of CFD analyses using the different turbulent models.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.15 no.2
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• pp.81-86
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• 2004

Background and Objectives : In general, ambulatory 24-hour pH monitoring is considered the current gold standard for larynogopharyngeal reflux(LPR). There is no validated instrument whose purpose is to document the physical finding and severity of laryngopharyngeal reflux. The purposes of this study are to revaluate the validity and reliability of the reflux finding score(RFS) and to quantify laryngoscopic findings using reflux finding score. Material and Methods : Thirty-three LPR patients confirmed by dual-probe pH monitoring and thirty patients of control were selected. The RFS was documented for each patient with telescopic laryngoscopy before treatment. For test-retest intraobserver reliability assessment, a blinded laryngologists determined the RFS on two separate occasions. To evaluate interobserver reliability assessment, the RFS was determined by t재 different blinded laryngologists. Results : The mean age of the cohort with pH-documented LPR was 45.8 years and the mean RFS was 11.4. The mean age of cotrol subjects was 52 years and the mean RFS was 5.4. The mean RFS for laryngologist no. 1 was 10.8 at the initial screening and 10.9 at the repeat evaluation. The mean FRS for laryngologist no.2 was 11.1 at the intial test and 10.9 at the repeat evaluation. The correlation coefficient for interobserver variability was 0.93 and intraobserver variability was 0.94. Conclusion : The RFS demonstrates excellent inter-and introaobserver reproducibility and is helpful for quantifying laryngeal finding in LPR. We can be 95% certain that an individual with a RFS greater than 7 has LPR.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9909-9913
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• 2014

Background: Helicobacter pylori (H. pylori) remains an important cause of gastric cancer and peptic ulcer disease worldwide. Treatment of H. pylori infection is one of the effective ways to prevent gastric cancer. However, standard triple therapy for H. pylori eradication is no longer effective in many countries, including Thailand. This study was designed to evaluate the efficacy of adding bismuth and probiotic to standard triple therapy for H. pylori eradication. Materials and Methods: In this prospective single center study, H. pylori infected gastritis patients were randomized to receive 7- or 14-day standard triple therapy plus bismuth with probiotic or placebo. Treatment regimen consisted of 30 mg lansoprazole twice daily, 1 g amoxicillin twice daily, 1 g clarithromycin MR once daily and 1,048mg bismuth subsalicylate twice daily. Probiotic bacteria composed of Bifidobacterium lactis, Lactobacillus acidophilus and Lactobacillus paracasei. Placebo was conventional drinking yogurt without probiotic. CYP2C19 genotyping and antibiotic susceptibility tests were also done. H pylori eradication was defined as a negative $^{13}C$-urea breath test at least 2 weeks after completion of treatment. Results: One hundred subjects were enrolled (25 each to 7- and 14-day regimens with probiotic or placebo). Antibiotic susceptibility tests showed 36.7% metronidazole and 1.1% clarithromycin resistance. CYP2C19 genotyping revealed 40.8%, 49% and 10.2% were rapid, intermediate and poor metabolizers, respectively. The eradication rates of 7- or 14 regimens with probiotics were 100%. Regarding adverse events, the incidence of bitter taste was significantly lower in the 7- day regimen with the probiotic group compared with 7- day regimen with placebo (40% vs. 64%; p=0.04). Conclusions: The 7-day standard triple therapy plus bismuth and probiotic can provide an excellent cure rate of H. pylori (100%) in areas with low clarithromycin resistance such as Thailand, regardless of CYP2C19 genotype. Adding a probiotic also reduced treatment-related adverse events.