• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.189-196
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• 1998

Swage sludge cakes produced from domestic wastewater treatment plants were collected from 21 different sites throughout Korea, and chemical properties of the sludge samples were determined. Inorganic nutrient contents did not indicate great differences among swage sludges from each sites, whereas the toxic heavy metal contents differed greatly. T-N, $NH_4{^+}-N$ and $NO_3{^-}-N$ contents from 21 sites sludges ranged 2.3-6.0, 291-4284, $1.4-58.8mg\;kg^{-1}$, respectively. Heavy metal (Cd, Cu, Pb and Zn) contents ranged 2.86-58.22, 144.0-5417.3, N.D.-943.5, and $N.D.-8,083mg\;kg^{-1}$, respectively. One of the sludges was treated to soils at rates of 12.5, 25, 50. and 100, $Mg\;ha^{-1}$ and incubated for 12 weeks to determine nitrogen materialization rate. Ammoniun nitrogen content decreased sharply at higher rates of sludge treatment up to 8 weeks after treatment and did not change much, while $NO_3{^-}$ increased at all treatment levels. The net amount of mineralized N of sludge treatment rates (12.5, 25, 50, and $100Mg\;ha^{-1}$) during 12weeks incubation were 189.0, 277.2, 303.8 and $376.6mg\;kg^{-1}$.

• Journal of Animal Science and Technology
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• v.46 no.3
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• pp.469-478
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• 2004

Pig slurry, urine and fermented liquid manure were evaluated measuring electrical conductivity (EC), dry matter (DM) contents and other components. Samples were collected during a period from February to April, 2001: slurry samples from 70 storage tanks, urine samples from 19 and 20 fermented liquid manure samples from 109 pig farms in Jeju. Samples were analyzed for pH, EC, DM, $NH_4$-N, K, P, Ca, Mg, Na, BOD, S-S, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn and OM. Relationships between EC or DM and various mineral and $NH_4$-N contents were examined using linear regression. EC, DM, all mineral contents and $NH_4$-N were higher in slurry samples than in urine or fermented liquid manure. EC, $NH_4$-N, Ca, Mg and Na concentration was similar in urine and fermented liquid manure, but K and DM values in liquid manure were twice as much as in urine. P concentration was higher in urine than in liquid manure. $NH_4$-N and Na in slurry, $NH_4$-N in urine and $NH_4$-N, P and Ca in fermented liquid manure were highly correlated with EC, while $NH_4$-N, P, Ca and Mg in slurry, $NH_4$-N and Ca in urine, and K, P, Ca, Mg, and Na in fermented liquid manure with DM (P<0.05). BOO in slurry (22,520 mg/mL) was higher than that in urine (4,763) and fermented liquid manure (2,701). Results indicated that slurry is a better fertilizer source than urine or fermented liquid manure. However, slurry may pollute soil more than urine or fermented liquid manure when applied to land, although the levels are not above the permit.

• Journal of Food Hygiene and Safety
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• v.26 no.3
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• pp.273-282
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• 2011

This study established hazards which may cause risk to human at farm during cultivation stage of paprika. Samples of plants (paprika, leaf, stem), cultivation environments (water, soil), personal hygiene (hand, glove, clothes), work utensils (carpet, basket, box) and airborne bacteria were collected from three paprika farms (A, B, C) located in Western Gyeongnam, Korea. The collected samples were assessed for biological (sanitary indications and major foodborne pathogens), chemical (heavy metals, pesticide residues) and physical hazards. In biological hazards, total bacteria and coliform were detected at the levels of 1.9~6.6 and 0.0~4.610g CFU/g, leaf, mL, hand or 100 $cm^2$, while Escherichia coli was not detected in all samples. In major pathogens, only Bacillus cereus were detected at levels of ${\leq}$ 1.5 log CFU/g, mL, hand or 100 $cm^2$, while Staphylococuus aureus, Listeria monocytogenes, E. coli O157 and Salmonella spp. were not detected in all samples. Heavy metal and pesticide residue as chemical hazards were detected at levels below the regulation limit, physical hazard factors, such as insects, pieces of metal and glasses, were also found in paprika farms. Proper management is needed to prevent biological hazards due to cross-contamination while physical and chemical hazards were appropriate GAP criteria.

• Journal of Food Hygiene and Safety
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• v.27 no.2
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• pp.152-160
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• 2012

The objective of this study was to analyze hazards for the growing stage of 6 tomato farms (A, B, C; soli farms, D, E, F; Nutriculture farms) located in Gyeongsangnam-do to establish the good agricultural practices (GAP). A total of 144 samples for analyzing hazards collected from cultivation environments (irrigation water, soil, nutrient solution, and air) and personal hygiene (hands, gloves, and cloths) were assessed for biological (sanitary indications and major food borne pathogens) and chemical hazards (heavy metals). Total bacteria, coliform, and fungi were detected at levels of 0.2-7.2, 0.0-6.1, and 0.0-5.4 log CFU/g, mL, hand or 100 $cm^2$, respectively. Escherichia coli were only detected in the soil sample from B farm. In case of pathogens, Bacillus cereus was detected at levels of 0.0-4.4 log CFU/(g, mL, hand or 100 $cm^2$), whereas Staphylococuus aureus, Listeria monocytogenes, E. coli O157, and Salmonella spp. were not detected in all samples. Heavy metals as a chemical hazard were detected in soil and irrigation water, but levels of them were lower than the permit limit. In conclusion, chemical hazard levels complied with GAP criteria, but biological hazards at the growing stage of tomato farms were confirmed. Therefore a proper management to prevent microbial contamination is needed.

• Korean Journal of Environmental Agriculture
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• v.23 no.3
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• pp.170-177
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• 2004

Agroenvironmental characteristics in paddy fields irrigated with the water of Nagdong river were analyzed along the river watershed for two years from 1999. The sites monitored from upper reaches of the river were Andong, Sangju, Gumi, Goryeong, Changnyeong, Milyang and Pusan. In paddy soils, the contents of heavy metals such as Cd, Cr, Cu, Pb, Ni, Zn and As were around natural values showing the highest values in Pusan followed by Goryeong. In brown rice, the contents of heavy metals were lower than natural values. Soil chemical properties appeared higher values in the lower reaches including Goryeong than the upper ones. The highest parameters in Goryeong were pH ($5.9{\sim}6.1$), EC ($0.8{\sim}0.9\;dS/m$), $Av.P_2O_5$ ($155{\sim}201\;mg/kg$), exchangeable Ca ($6.7{\sim}7.4\;cmol^+/kg$), Mg ($1.92{\sim}2.50\;cmol^+/kg$), K ($0.18{\sim}0.21\;cmol^+/kg$) and those in Pusan were organic matter ($23.0{\sim}29.1\;g/kg$) and T-N ($1.6{\sim}1.8\;mg/kg$). In conclusion, the recommended rates of N fertilizer for rice cropping were 21.4%, 11.8% and 8.8% high for Andong, Sangju and Gumi, respectively and 14.9%, 4.6%, 4.5% and 11.5% low for Goryeong, Changnyeong, Milyang and Pusan, respectively reflecting the chemical properties of soils and the quality of irrigation water on the basis of 110 kgN/ha. In the case of phosphorous, the rates were 18.9% and 33.3% low for Changnyeong and others, respectively on the basis of $45\;kgP_2O_5/ha$. The populations of bacteria, fungi, actinomycetes, Bacillus, fluorescent Pseudomonas and Biomass C were high at the lower reaches including Goryeong, which showed relatively much nutrient contents of organic matter, total N and phosphorous etc.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.5
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• pp.514-523
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• 2004

Statement of problem: All-ceramic restorations have been advocated for superior esthetics. Various post and core systems have been used to improve the strength of damaged teeth, but it is unclear whether they affect the final shade of finished all-ceramic restorations. Purpose: The influence of different types of post and core systems on light transmission through all-ceramic crowns was assessed by spectrophotometric analysis. Also the masking effect of different thickness of ceramic ingot was evaluated. Material and Methods : Forty-five sample disks (15mm in diameter) at several thickness(1.0, 1.5, 2.0mm) and value(shade 100, 200, 300) were made in heat pressed ceramic(IPS-Empress). Background specimens simulating gold-alloy cast posts(Type III casting gold alloy), metal posts(Ni-Cr casting alloy) and ceramic posts(CosmoPost) were fabrica-ted. Resin composite(Z250, A3 shade) was used as a tooth substrate reference. For each combination, the change in color was measured with a spectrophotometer. Readings were performed for 2 conditions (1) ability of ceramic to mask the core in relation to its thickness(1.0, 1.5, or 2.0mm) ; (2) influence of post and core types on the final color of the ceramic. Data were recorded according to the CIE $L^*a^*b^*$ systems and color difference($\Delta$E) was calculated. Results: 100 shade ingot: when ceramic thickness was 1.0mm, $\Delta$E value for ceramic post larger than 1 but $\Delta$E value for metal and gold post was larger than 2. For ceramic thickness of 1.5mm, only $\Delta$E value for metal was larger than 2, and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 2. 200 shade ingot: when ceramic thickness was 1.0mm, $\Delta$E value for ceramic post was smaller than 1 but $\Delta$E value for metal and gold post was larger than 2. For ceramic thickness of 1.5 mm, only the $\Delta$E value for metal was larger than 2, and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 1. 300 shade ingot: when ceramic thickness was 1.0mm, only $\Delta$E value for metal was larger than 2 and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 1.5mm, $\Delta$E values for all specimens was smaller than 1. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 1. Conclusion: The final esthetic result of the IPS-Empress glass-ceramic restoration was not affected by the presence of different core materials when the thickness was more than 2.0 mm. When ceramic thickness decreases to 1.5mm, it is advised to take the substrate aspects into consideration. If the ceramic thickness is less than 1.0mm, using the tooth color matched substrate is strongly recommended.

• Analytical Science and Technology
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• v.23 no.5
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• pp.485-491
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• 2010

A certified reference material (CRM) of KRISS 109-03-SSD was developed for the analysis of hazardous elements in soil. The target elements were As, Cd, Cr, Cu, Hg, Ni, Pb, Zn being regulated by the Soil Environment Conservation Act. Starting material was collected from tailing dump of an unworked tungsten mine at Sangdong (Gangwon-do, Korea). The starting material under-went through a series of fabricating process steps of screening, drying, grinding, sieving, blending, bottling, sterilization and was certified according to the ISO Guide 35. Isotope dilution-inductively coupled mass spectrometry (ID-ICP/MS) and instrumental neutron activation analysis (INAA) were used for the measurement. Homogeneity was tested according to ISO 13528 annex B. The certified values were determined using the results from two different methods or from two independent measurements using a method. Finally, certified values of seven elements of arsenic, cadmium, chromium, copper, lead, nickel and zinc were determined. Mercury did not satisfied the criteria of homogeneity and the result would be provided for information only, together with iron and tungsten. It was also studied, the extractable fraction of elements by aqua regia according to the ISO 11466 protocol being frequently studied for the purpose of environmental monitoring. It was performed as a inter-laboratory study by 6 laboratories of a public institute and universities. Standard deviation among the laboratories was much bigger than the uncertainty of the certified value. The result of inter-laboratory study on the extractable fraction will be provided for information, only.

• Economic and Environmental Geology
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• v.42 no.2
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• pp.121-131
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• 2009

The distribution characteristics of heavy metals for surface sediments in east oceanic dumping area (EDA) and west oceanic dumping area (WDA) are evaluated by grain sizes, minerals, sedimentation rates and compositions of heavy metals. The mean grain sizes in EDA and WDA range from $7.95{\Phi}$ to $8.51{\Phi}$ and $7.42{\Phi}$ to $8.15{\Phi}$, respectively. These are mostly belonging to the M (mud) type. Minerals in the surface sediments consist of illite with chlorite, smectite, and kaolinite. Sedimentation rates estimated by $^{210}Pb$ method in EDA and WDA are 1.11 mm/yr$\sim$1.73 mm/yr and 1.87 mm/yr, respectively. According to the interrelationship, concentrations of Ni, Cu, Cr, and Zn are closely associated with mean grain size, Al, and Fe, whereas concentrations of Cd and Pb are poorly associated with ones. The enrichment factors of these elements are higher than 1.5, suggesting that the concentrations of Cd and Pb in the surface sediments are affected by anthropogenic sources. The $I_{geo}$-class numbers of Cd and Pb in the surface sediments are mostly classified in 2 to 4, showing moderate to strongly polluted. These numbers in EDA are higher than that of WDA, and the highest number is 4, indicative of the strongly polluted class. Our results show that the disposed wastes at EDA include mineralogical wastes, dredged materials from sewage disposals, and sludges from constructions having materials of WDA. The annual amount of oceanic dumping in EDA is double than that in WDA.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.4
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• pp.791-799
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• 1996

The purpose of this study was to compare the shear bond strength of adhesion bridge by various resin cements. One hundred and foully 1st premolars were used. The teeth were cut below 2mm from CEJ and the coronal portions were used. The coronal portions were embeded with the acrylic resin and trimmed with sic paper until the flat plane with ${\phi}$ 4mm above acrylic resin sticks in height 5mm were casted with nonprecious metal and the using surfaces were treated with sic paper from #200 to #1200 and polished with alminum oxide paste. And then, the using surfaces were sandblasted and treated with the electrochemical etching. The teeth were divided into three groups of fourty two each. In group I, teeth and specimens were cemented with Panavia 21 In group II, teeth and specimens were cemented with Superbond In group I, teeth and specimens were cemented with All-Bond & composite resin cement Each group was subdivided into three subgroups according to the storage period ; one-day storage, fifteen-day storage, and thirty-day storage. The special jig was made. Then, the specimen and jig were mounted to Instron Universal Testing Machine and the failure were measured. The results were as follows. 1. There was statisfically significant difference between the failure loads of group I and group II and III after one day storage(P<0.01), 2. There was statisfically significant difference between the failure loads of group II and group I and III and between group I and group III at fifteen day storage(P<0.01). 3. There was statisfically significant difference between the failure loads of group I and II and group III after thirty day storage(P<0.01). 4. There was statisfically significant difference between the failure loads of one day storage and fifteen and thirty days storages in group III (P<0.01).

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.4
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• pp.235-242
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• 2012

Purpose: The purpose of this study was to compare the fracture behavior of Zironia, glass infiltrated Alumina and PFM full crown system. Materials and methods: Fifteen crowns for each of 3 experimental groups (Zironia, glass infiltrated Alumina and PFM full crown) were made by the conventional method. The crowns mounted on the testing jig were inclined in 30 degrees to the long axis of the tooth and the universal testing machine was used to measure the fracture strength. Results: 1. The mean fracture strengths were $588.3{\pm}49.6MPa$ for zirconia system, $569.1{\pm}61.8MPa$ for PFM system and $551.0{\pm}76.5MPa$ for glass-infiltrated alumina system (P>.05). 2. The mean shear bond strengths were $25.5{\pm}5.6MPa$ for zirconia system, $38.9{\pm}5.0MPa$ for Ni-Cr alloy system and $39.4{\pm}5.1MPa$ for glass-infiltrated alumina system. 3. The chemical bonding was observed at interfaces between PFM or glass-infiltrated alumina and veneering porcelain, however, no chemical bonding was observed at interface between zirconia and veneering porcelain. Conclusion: With the study, the fracture strengths of PFM crown system had a higher fracture strength than conventional zirconia system crown and glass-infiltrated alumina crowns. and than the shear bond strengths glass-infiltrated alumina system had a higher shear bond strength than conventional PFM system and zirconia system.