• Journal of environmental and Sanitary engineering
• /
• v.19 no.4 s.54
• /
• pp.25-33
• /
• 2004

Acrylamide, difficult to analyze by GC and GC/MS due to the polarity and low volatility, was analyzed by LC/ESI/MS in the study. Acrylamide its(molecular weight 71amu) showed m/z=72 $(M+H)^+$ and high peak intensity at 22V in SIR mode. The mass spectrum ratios of acrylamide for qualitative identification had m/z=72 in precursor ion and m/z=55 in products ion, respectively. Those ratios at 30V in SIR mode ranged from 1: 1.4 to 1:1.17 despite various acrylamide concentrations. The ion intensity ratios of acrylamide $(m/z=72,\; [M+H]^+)$ to acrylamide isotopes $(m/z=73,\;[M+H]^+)$ ranged from 100 : 3.57 to 100 : 3.92. The results verified theoretical mass spectrum ratio that was 100:3.82. The linearity of standard calibration curve was y : 520.584x + 1815.26 with $r^2=0.99.$ In quality assurance and quality control, the recovery rate ranged from 81.64 percent to 90.97 percent and relative standard deviation was less than $10\%$ with 5 repeated injections at individual standard calibration solutions. The method was applied to analyze acrylamide in food at grocery stores. Snacks made of potatoes showed the highest acrylamide concentration followed by products made of French fries, wheat, and corn.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.21 no.6
• /
• pp.277-286
• /
• 2017

On September 12, 2016, Gyeongju earthquake occurred. Its local magnitude was announced to be $M_L=5.8$ by Korea Meteorological Administration (KMA). Ground motion data recorded at KMA, EMC and KERC stations was obtained from their data bases. From the data, horizontal and vertical response spectra, and V/H ratio were calculated. The horizontal spectrum was defined as geometric mean spectrum, GMRotI50. From the statistical analysis of the geometric mean spectra, a mean plus one standard deviation spectrum in lognormal distribution is obtained. Regression analysis is performed on this curve to determine the shape of spectrum including transition periods. Applying the same procedure, the shape and transition periods of vertical spectrum was obtained. These results were compared with the Korean standard design spectra, which were developed from domestic and overseas intraplate earthquake records. The response spectra of Gyeongju earthquake were found to be almost identical with the newly proposed design spectra. Even the V/H ratios showed good agreement. These results confirmed that the method adopted when developing the standard design spectra were valid and the developed design spectra were reliable.

• Korean Journal of Environmental Biology
• /
• v.38 no.2
• /
• pp.248-253
• /
• 2020

The level at which analyses of DNA content might contribute more significantly to the genetic mechanisms of evolution lies in the events of speciation. The object of this study was to investigate the DNA content of abalone (Haliotis discus hannai) and determine the optimal tissue samples for measuring the DNA content of abalone by flowcytometry without fixation. The DNA content (pg/nucleus) of gill tissue (2.5±0.08), which was contaminated with protozoa, was significantly lower than that of muscle tissue (3.2±0.02), mantle tissue (3.2±0.02) (p<0.05), and a standard reference standard, while the DNA contents of muscle tissue and mantle tissue were higher than that of the standard reference. Considering the results of this study, DNA content analysis with flowcytometry is an acute and rapid method by which muscle tissue and mantle tissue are the most appropriate sample for measuring the DNA content of abalone without fixation.

• Journal of Environmental Health Sciences
• /
• v.15 no.2
• /
• pp.33-40
• /
• 1989

Dichromate reflux method for COD analysis is one of the useful and precise way to solve the organic content of the wastewater. But the standard procedure for COD is not entirely satisfactory for sample containing appreciable amounts of inhibiting substance, especially chloride ion. Under the conditions of the established test, a big disadvantage of the method is that dichromate oxidizes chloride quantitatively to chlorine. When it is necessary to use silver sulfate as a catalyst in the COD procedure, chloride must be removed before the addition of the catalyst. Silver sulfate and mecuric sulfate forms a precipitate of AgCl and HgCl$_{2}$ separately which is not completely oxidized during the test and, therefore, cannot be corrected for. So, we evaluate and compensate the amount of chloride oxidation in the absence of chemicals during the experimental procedure. Calculation of COD is made using the following reviced formula: real COD = tested COD - 0.2277Cl.

• Journal of Environmental Science International
• /
• v.12 no.4
• /
• pp.447-459
• /
• 2003

This study was carried out to develop an efficient process far the elimination of phenol pollutant from soils. An microwave-assisted process (MAP) and a conventional Soxhlet extraction method (SEM) were employed to extract phenol from two types of soils. The effects of extraction methods, aged time of the spiked soil samples, extraction solvent and extraction time on the extraction performance were compared. Our results demonstrate that the recoveries from standard soil spiked were at least 10% higher fer MAP than these f3r the conventional Soxhlet. The extraction time by MAP requires significantly shelter time (1 min) than 15 h of the conventional Soxhlet. The recoveries from non-contaminated soil spiked with phenol were also almost identical f3r above results. The reduction of the extraction times with efficiency higher than that afforded by the conventional Soxhlet technique supports the suitability of the MAP method.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.13 no.4
• /
• pp.249-262
• /
• 2010

Regulatory test method for Total Petroleum Hydrocarbons (TPHs) in the marine sediment and biota has not still been established even though TPHs are one of the major pollutants in marine environment. Based on the Korean Soil Standard Method (SSM) for TPHs, we considered a new treatment method for determining TPHs in marine environmental samples by using a Gas chromatography coupled with Mass spectrometric detector. We suggested an improved recovery test for quality control procedures and introduced analytical procedures of removing sulfur, polar organic materials, water and saponification for removing neutral lipids in marine bottom sediments and biota.

• Journal of the Korean Home Economics Association
• /
• v.51 no.1
• /
• pp.89-95
• /
• 2013

The purpose of this study is to identify a causal relationship among green consumer behavior, environmental knowledge and environmental attitudes of students at the university of education. A total of 366 copies of questionnaires were used for the data analysis; 31 copies were excluded due to lack of response to any given question. To ensure the reliability and validity of the questions, technical statistics were performed, such as frequency, ratio, average, standard deviation, skewness, and kurtosis via SPSS 15.0, item-total correlation and the totality, and reliability analysis. A structural analysis was undertaken via AMOS 7.0 in a bootstrapping method in order to perform a path analysis among variables as well as to assess the suitability of the model. The findings of the study were led to the following conclusions: First, the causal model among green consumer behavior, environmental knowledge and environmental attitudes of students at the university of education is suitable to the empirical analysis on research variables. Second, the environmental attitudes of students at the university of education has a direct, positive effect on green consumer behavior. Third, the environmental knowledge of students at the university of education has an indirect, positive effect on green consumer behavior.

• Journal of the Korean Society of Safety
• /
• v.22 no.5
• /
• pp.33-40
• /
• 2007

Standard safety management costs can not be applied to each site with same rate, it is very difficult, because it depends on the experience, work method, work kind, work progress schedule, and hazard level of each construction company. Therefore, this study is to find out hazard level of each work kinds through questionnaire and interview and investigate analyze the status which standard safety management costs have been used. Also, this study is to show reasonable rates of standard safety management costs in construction industry and to set up countermeasures against those problem after reviewing its status in korea with in Japan and Europe. This study is to investigate eleven project kinds of domestic system, first, and to investigate eleven items of apartment bldg, office. Also this study is to investigate and analyze performed costs of presently processing worker finished work so that it shows a new reasonable rate against standard safety management costs in construction industry, in order to make basical data and material to be systemized.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.73-73
• /
• 2010

Various organic- and bio-conjugated nanoparticles have been studied extensively for biological applications in medical diagnoses and drug delivery systems. Gold nanoparticles (AuNP) and poly(ethylene glycol) (PEG) are known biocompatible materials to be used in vivo and are becoming increasingly important in biomedical applications. In this work, we investigated the stability of PEG-conjugated AuNPs, dialysis and centrifuge effects after synthesis or pegylation of AuNPs as a function of elapsed time by using ToF-SIMS imaging technique along with dynamic light scattering (DLS), UV-visible absorption spectroscopic and statistical analyses. Roughly 15-nm-sized AuNPs were synthesized in a citrate-conjugated form, and then converted into the thiol-terminated PEG (O-[2-(3-Mercaptopropionylamino)ethyl]-O'-methylpolyethyleneglycol, M.W.=5 kDa) form. Based on our data, we will show that ToF-SIMS imaging analysis along with DLS, UV-visible absorption and statistical analyses would be a useful method to evaluate stability of PEG-conjugated AuNPs in various environmental conditions.

• Environmental Engineering Research
• /
• v.24 no.2
• /
• pp.246-253
• /
• 2019

This study was conducted to explore the optimum proportion of zeolite and zeolite-kaolin as additives to cement clinker and gypsum samples, while maintaining the strength properties of produced environmentally sustainable cements. According to the British standard method, zeolite was added to cement clinker in proportions of 5-12% and 10-12% by weight, respectively, in the preparation of samples of zeolite-containing cement and zeolite-kaolin-based cement. Kaolin was used as a second additive as 10-20% of the total weight. The compressive strength tests were performed on base cement samples according to a standard procedure given in ASTM C109 Compressive Strength of Hydraulic Cement. These values were compared with those of the reference sample and the Omani allowable limits. The results indicated that the best compressive strength values were obtained with 88% cement clinker, 5% gypsum, and 7% zeolite for the zeolite-containing cement. Quantities of 70% cement clinker, 5% gypsum, 10% zeolite, and 15% kaolin gave the best results for zeolite-kaolin-based cement, resulting in a substitution of than 25% cement clinker. The study concluded that the partial cement clinker replacement using zeolite/kaolin combination may have a great influence on the reduction of $CO_2$ emission and energy saving in cement manufacturing.