• Analytical Science and Technology
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• v.23 no.5
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• pp.465-476
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• 2010

In this study, a number of volatile organic compounds (VOCs) including benzene, toluene, p-xylene, styrene, and methyl ethyl ketone were analyzed from samples collected in ambient air and under the field conditions. These samples were analyzed independently by two different set-ups for VOC analyses, i.e., between [1] gas chromatography/flame ionization detector with tube sampling - (F-T system) and [2] gas chromatography/mass spectrometer with bag sampling (M-B system). The analytical results derived by both systems showed fairly similar patterns in relative sense but with moderately large differences in absolute sense. The results of M-B system were high relative to F-T system with the F-T/M-B ratio below 1. If the relative biases of the two measurement techniques are derived in terms of percent difference (PD) in concentration values, the results were generally above 35% on average. A student t-test was applied to investigate the statistical significance of those differences between the systems. The results of both analytical systems were different at 95% confidence level for toluene, p-xylene, styrene, and methyl ethyl ketone (P < 0.043). However, F-T and M-B systems showed strong correlations for toluene and p-xylene. The observed bias is explained in large part by such factors as the differences in standard phases used for each system and the chemical loss inside the bag sampler.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.433-442
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• 2021

In this study, the properties of no-fines polymer concrete with different polymer binder contents were evaluated. The polymer concrete was formulated using a polymeric binder (unsaturated polyester resin), fly ash, and recycled coarse aggregate (60%) and crushed coarse aggregate (40%). The polymeric binder content (4.0-6.0wt.%) was used as an experimental variable because it dramatically affects both the cost-effectiveness and material properties. The results showed that the density, compressive strength, flexural strength both before and after exposure to freezing and thawing increased as the polymer binder content increased, while the absorption, void ratio, permeable voids, coefficient of permeability, and acid resistance (mass loss by acid attack) decreased as the polymeric binder content increased. In particular, even though the void ratio was 18.4% and the water permeability coefficient was 7.3mm/sec, the compressive strength and flexural strength were as high as 38.0MPa and 10.0MPa, respectively, much more significant than those of previous studies. Other properties such as absorption and acid resistance were also found to be excellent. The results appear to be rooted in the increased adhesion of the binder by adding a cross-linking agent and the surface hydrophobicity of the polymer.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.5
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• pp.354-361
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• 2008

In this study, we analyzed nutrient cycling structure of a small farm (cattle of 100 heads and arable lands of 2.5 ha) in Jeonnam province to investigate the effects of nutrients input by the addition of bedding materials (sawdust and rice hull) and nutrients loss before the application to the soils (the period during manure storage in the feedlot and composting process) on nutrient cycling structure. Sawdust and rice hull added as bedding materials increased N by 1.6% and 14.2% and $P_2O_5$ by 3.1% and 27.4%, respectively, relative to the amount of nutrients produced by excretion. This result suggests that the addition of nutrients via bedding materials should be considered for better estimation of nutrient balance. The most significant characteristics of the nutrient cycling structure was loss of mass and nutrients during the storage (21 days) and composting period (90 days). During this period, 78.4% of N and 9.5% of $P_2O_5$ was lost from sawdust compost; meanwhile, the percentages of loss for rice hull compost were 81.6% and 10.3%, respectively. A lower percentage of nutrients loss in sawdust compost than that in rice hull compost was attributed to the relatively slow decomposition rate of organic materials in the sawdust compost which has higher C/N ratio and lignin contents. Therefore, it was concluded that estimation of nutrient balance should be conducted based on nutrient contents in the final compost being applied to the lands rather than the amount of nutrients contained in the livestock excretion. In addition, the effects of bedding materials on nutrient losses should be also taken into account.

• Korean Journal of Environment and Ecology
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• v.24 no.4
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• pp.426-435
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• 2010

The present study attempts to compare the soil chemical characteristics and biological activities (i.e. microbial biomass and soil enzyme activities), and litter decomposition rate of Arundinella hirta and Miscanthus sinensis var. purpurascens) collected from serpentine and non-serpentine sites by litter bag techniques at serpentine and non-serpentine field experiment sites over a 9-month period. The serpentine soil showed higher pH and soil alkaliphosphatase activity, and lower soil dehydrogenase and urease activities than the non-serpentine soil. Microbial biomass-N at the serpentine soil was larger than the non-serpentine soil, although the microbial biomass-C and microbial biomass-N represented no significant difference between serpentine and non-serpentine soil. These results suggest that the larger microbial biomass-N caused the lower C/N in serpentine soil. At the end of the experiment, the litter samples of A. hirta and M. sinensis collected from serpentine soil revealed a 39.8% and 38.5% mass loss, and the litter sample from non-serpentine soil also showed a 41.1% and 41.7% mass loss at the serpentine site. On the other hand, at the non-serpentine site, 42.2%, 37.4%, and 46.8%, 44.8% were respectively shown. These results demonstrate that the litter decomposition rate is more intensely affected by the heavy metal content of leaf litter than soil contamination. Moreover, the litter collected from the serpentine soil had a lower C/N, whereas the litter decomposition rate was slower than the litter from the non-serpentine soil, because the heavy metal inhibition activities on the litter decomposition process were more conspicuous than the effect of litter qualities such as C/N ratio or lignin/N. The nutrient element content in the decomposing litter was gradually leached out, but heavy metals and Mg were accumulated in the decaying litter. This phenomenon was conspicuous at the serpentine site during the process of decomposition.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.733-742
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• 2000

Fundamental materialistic characterization and adsorption/neutralization behavior of waste egg shell for heavy metal ion have been studied for its application to wastewater treatment. To investigate the structural change and thermal decomposition characteristics of egg shell. X-ray diffraction and FT-IR analysis were conducted for egg shell treated at $105^{\circ}C$ and $700^{\circ}C$, respectively. For the result of FT-IR analysis, the sample treated at $700^{\circ}C$ showed a reduced C-O absorption band compared with that of egg shell treated at $105^{\circ}C$, which may be due to the $CO_2$ release. Unlike to the result of FT-IR analysis, the XRD patterns of egg shell were almost similar for the cases of $105^{\circ}C$ and $700^{\circ}C$ treatment. however, characteristic diffraction pattern of CaO was observed for $850^{\circ}C$ treatment, at which $CaCO_3$ is known to be completely converted to CaO. TGA/DTA analysis showed a slow decline in weight loss up to $600^{\circ}C$ and, for $600{\sim}800^{\circ}C$ range, the weight loss became drastic by reason of $CO_2$ discharge, which was accompanied by an appearance of major endothermic peak. The ratio of practical breakthrough time to ideal one, total transfer unit, and mass transfer coefficient were observed to be increased as the adsorption was progressed in a multiple-column fixed-bed reactor using egg shell as an adsorbent, which signified the distribution effect of mass transfer for continuous adsorption reaction. The neutralization effect of egg shell for several types of acidic wastewater made of different mineral acids was not much different from each other except for the case of $H_2SO_4$, for which the neutralization reaction was thought to be retarded by the formation of gypsum.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.33-40
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• 2013

The cement industry brought very severe environment problems with massive carbon dioxide during its production. To solve this problem, attempts on Alkali-Activated Slag (AAS) concrete that perfectly substitutes industrial by-products such as ground granulated blast furnace slag (GGBFS) for cement are being actively made. AAS concrete is possible to have high strength development at room temperature, however, it is difficult to ensure the working time due to the fast setting time and the loss of workabillity because of the alkali reaction. In this study, the early age properties of alkali activated slag mortar are investigated to obtain the fundamental data for AAS concrete application to structural members. The water-binder ratio (W/B) was fixed at 0.35 and sodium hydroxide and waterglass as alkali activator was used. The compressive strength, the flow and the ultrasonic pulse velocity were measured according to the type of superplasticisers, which were naphthalene(N), lignin(L), melamine(M) and PC(P), up to a maximum of 2 percent by the mass of GGBFS. The results showed that adding melamine type of superplasticizer improved the fluidity of AAS mortar without decreasing the compressive strength, while naphthalene and polycarbonate type of superplasticizer had little effect on the fluidity of AAS mortar.

• Tuberculosis and Respiratory Diseases
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• v.38 no.4
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• pp.340-346
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• 1991

Tuberculous tracheobronchitis is defined as a specific inflammation of the trachea or major bronchi caused by the tubercle bacillus and recognized as one of the most common and serious complication of pulmonary tuberculosis. It had been a diagnostic challenge in prebronchoscopic era and since 1968, fiberoptic bronchoscopy has been accepted as a safe and valuable diagnostic procedure of tuberculous tracheobronchitis. Now, it remains a troublesome therapeutic problem due to its sequelae such as bronchostenosis, bronchiectasis and bronchial deformity. The authors analyzed the clinical features, radiological findings and bronchoscopic findings with pathologic and bacteriologic study on 61 cases of tuberculous tracheobronchitis and following results were obtained. 1) The peak incidence was in the fourth decade and male to female ratio was 1:3.4. 2) The most common symptom was cough (86.9%) and followed by sputum (49.2%), dyspnea (27.9%), fever (19.8%), weight loss (11.5%), hemoptysis (6.6%), hoarseness (6.6%) and chest discomfort (3.3%) and localized wheezing was heard in 18%. 3) In chest X-ray, consolidation with collapse was observed in 70.5%, and followed by consolidation only (18.0%), mediastinal node enlargement (8.2%), cavitary lesion (6.6%), suspicious hilar mass (3.3%) and miliary lesion (1.6%) and there was no abnormal findings in 4.9%. 4) Bronchoscopy showed hyperplastic lesion in 67.2%, mucosal lesion (18.0%), ulcerative lesion (9.8%) and stenotic lesion (4.9%). The most common site of bronchial lesion was right upper bronchus (36.1%) and followed by right main bronchus (34.4%), left main bronchus (29.5%), left upper bronchus (16.4%), right middle bronchus (8.2%), right lower bronchus (6.6%) and left lower bronchus (3.3%). 5) Chronic granulomatous inflammation with or without caseation necrosis on microscopic examination was confirmed in 69.7%, bronchial washing AFB stain was positive in 34.1%, prebronchoscopic sputum AFB stain was positive in 88.1% and postbronchoscopic sputum AFB stain was positive in 30.1%.

• Journal of Nutrition and Health
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• v.30 no.2
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• pp.155-169
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• 1997

This study investigated the effect of weight control by using the commercial appetite suppressant ((-)-hydroxycitric acid(HCA) formula) and nutrition education on 72 obese women over a period of 8 weeks. During the study it conducted nutritional education for women to control their weight, thus analyzed their changes in anthropometric variables. All obese women were randomized in a double-blind method to consume either HCA(HCA group : experimental group) or placebo(placebo group : control group). Two groups were also divided randomly into 2 groups combined with commercial formula diet in 1 meal a day(HD group and PD group : HCA + gormula diet and placebo + formula diet) or not(HO group and conducted with 4 groups(HD, HO, PD, and PO group). All subjects were assigned to consume 800-1500kcal/d balanced diet which is 500kcal less than their usual energy requirement. To evaluate the effect of the weight control program, weight, percent of body fat, waist and hip circumferences, and 5 skinfold thickness were measured up to 5 times in all obese women. The mean weight of the subjects at the onset of the study was 76.5$\pm$10.6kg. The mean body mass index(BMI) wa 30.1$\pm$3.8 and it was in the upper 5 percentile of mean BMI of Korean women. At the end of the program, mean weight loss was 3.5kg after 2 weeks(p<0.001), and 5.8kg after 4 weeks(p<0.001). The waist, hip ratio(WHR) and skinfold thickness measurements of biceps, triceps, subscapular, suprailiac and abdominum showed significant reduction over the entire study period(p<0.05). These outcome were evaluated by effect of nutritional education and counselling. The reduction of % of body fat was significantly different among the 4 groups. Women who administrated HCA demonstrated more change in weight, BMI than the placebo group. There was also significant reduction in body composition (% of body fat, WHR, and skinfold thickness) than the other groups. The HD group which was administrated HCA combined with formula diet was more decreased than other groups. It showed that this program using commercial HCA and formula diet induced not only a change in weight but also a change in body composition. The outcome of this study suggests that HCA has a more effctive change on weight control which is carried out with nutritional education and counselling.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.768-776
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• 2015

This study was performed to understand combustion properties four major Indonesian wood species such as Albizia, Gmelina, Mangium and Mindi were investigated by cone-calorimeter for better utilization of theses wood species. Heat release rate (HRR), total heat release (TSR), specific mass loss rate (SMLR), effective heat of combustion (EHC), time to ignition (TTI), flame time (FT), specific extinction area (SEA), smoke production rate (SPR) and CO compound production rate were measured. HRR, THR and FT were proportional to the density of woods. Albizia showed the highest HRR, while Mindi had the lowest HRR. For SPR, Albizia showed the highest value due to its higher SEA. On the other hand, Mindi had the lowest SPR due to a lower SEA value. The highest smoke emission was for Albizia at the beginning of combustion. After 300 seconds, smoke emission of Gmleina and Mangium was increased greatly. Mangium and Mindi showed the highest total carbon dioxide emission. Expecially, Gmelina released the highest carbon monoxide during the combustion period and presented three times higher $CO/CO_2$ ratio than those of other species due to incomplete combustion.

• Korean journal of communication and information
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• v.49
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• pp.57-80
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• 2010

This study examines how national newspapers interpret, evaluate and report the Korean grand canal and rebuilding four major rivers through the news writings. For this research, ChosunIlbo, the Hankyoreh Shinmun and HankukIlbo are selected. A total of 961 news writings are analyzed by using the concept of news frame designed by Gamson(1993). As a result, the findings are as follows: First, the most frequently reported news frame for ChosunIlbo is economic consequence; the Hankyoreh for ecological environment, and HankukIlbo for authoritative political execution by the administrative. Second, the most frequently interviewed group through all of the papers is the administrative and the ruling Grand National Party, the main body of rebuilding the Korean grand canal. On the country, voices of environmental protection groups, non-profit civic organizations and the ordinary people are reported rarely. Third, the ratio of authoritative political execution by the administrative and economic consequence are very high. Finally, in terms of the framing activity by the interviewed groups in the newspapers, ChosunIlb reports 'Outcome' the most frequently, the Hankyoreh does 'Loss-gain' & 'Process' and HankukIlbo 'Process' & 'Substantive'. Thus it concluded that ChosunIlbo does not play a role as a social mediator for the social disputes. However, the Hankyoreh and HankukIlbo try to represent environmental and civic organizations fairly.