• Journal of Korean Society of Occupational and Environmental Hygiene
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• 제18권4호
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• pp.293-302
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• 2008

Lead chromate is made by sodium dichromate and lead acetate, and has being used widely in the part of pigment, paints, inks, plastics and so on. Even though lead chromate has health hazards which like both lead and chromium, there are a few study about pigment workplaces using lead chromate in Korea. The purpose of this study is to evaluate workers' exposure levels and airborne lead and chromium concentration in the pigment workplaces using lead chromate. There are 20 workers in the total 5 workplaces. 10 workers(50%) have been exposed to lead and 3 workers(15%) have been exposed to chromium, which exceeded the American Conference of Governmental Industrial Hygienists(ACGIH) Threshold Limit Value (Pb: $0.05\;mg/m^3$, Cr: $0.012\;mg/m^3$) and Korean Ministry of Labor's Standard. Geometric mean (GM) of airborne lead was highest in pigment ($0.0421\;mg/m^3$), paint ($0.0020\;mg/m^3$) and PVC coloring ($0.0007\;mg/m^3$), respectively(p<0.05). The result of airborne chromium concentration was paint ($0.0033\;mg/m^3$), paint ($0.0004\;mg/m^3$) and PVC coloring ($0.0003\;mg/m^3$). Also the lead and chromium concentration in the manual process is each 30 times and 10 times higher than the value in automatic process(p<0.01). In the classified process by detail, the concentration of airborne lead was $0.0638\;mg/m^3$ in grinding & packaging, mixture & after-measuring ($0.0436\;mg/m^3$), filtration & drying ($0.0402\;mg/m^3$), lead nitrate & dissolution($0.0129\;mg/m^3$), pigment commitment & mixture ($0.0013\;mg/m^3$) and dispersion & grinding ($0.0010\;mg/m^3$) (p<0.05). Moreover the concentration of a sample in weighting & packaging was $0.0023\;mg/m^3$. The concentration of lead in workers' blood was pigment (15.12 ug/dl), paint (4.74 ug/dl) and PVC coloring (2.50 ug/dl), and some samples have exceeded biological exposure limit. In conclusion, the depending on their work industry and process, workers have been exposed to the high lead chromate.

• Journal of Forest and Environmental Science
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• 제34권4호
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• pp.284-292
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• 2018

The study investigated the concentrations of Pb in soil, air and fruit of C. sinensis in selected landuse types in Port Harcourt Metropolis, Rivers State, Nigeria. Five fruits of C. sinensis were collected randomly in residential, commercial, industrial and natural forest (control). The weight, length and width of the C. sinensis fruits were measured. A total of three soil samples were collected around the C. sinensis trees where the fruits were collected into well labeled polythene bags and thereafter taken to laboratory for analysis. Pb concentrations in C. sinensis and soil samples were analysed using atomic absorption spectrophotometer (AAS). The concentration of Pb in the air was measured for 14 days using Aeroquel 500. The significant relationship between Pb concentration in the C. sinensis fruits, soil and air was determined using Spearman's rank correlation. Findings showed that the mean weight and width of C. sinensis fruits were highest in the residential landuse while the mean length of C. sinensis fruits was highest in the industrial landuse. However, the mean Pb concentration in the C. sinensis fruit was highest in the industrial landuse ($0.46{\pm}0.15mg\;kg^{-1}$), commercial landuse ($0.33{\pm}0.09mg\;kg^{-1}$) and the least was found in the natural forest ($0.25{\pm}0.06mg\;kg^{-1}$). The mean Pb concentration in the soil was highest in the industrial landuse ($0.177{\pm}0.16mg\;kg^{-1}$) and commercial landuse ($0.121{\pm}0.10mg\;kg^{-1}$). However, the mean Pb concentration in the air was highest in the industrial landuse ($0.85{\pm}0.09mg\;kg^{-1}$) and followed by commercial landuse ($0.30{\pm}0.17mg\;kg^{-1}$). The correlations between the Pb concentration in the C. sinensis fruit and soil (r=0.768, p<0.05) and air (r=0.642, p<0.05) were significant. The study concluded that the Pb concentration in the C. sinensis fruits was higher than the WHO standard; hence people should be discouraged to consume them, especially those from the industrial and commercial areas.

• Journal of Industrial Technology
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• 제7권
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• pp.59-68
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• 1987

In order to obtain a strain of producing lipase which has resistance against alkaline and detergent, a screening test was carried out. Among 500 strains isolated from soil samples, the strain J-19 was selected for this study. The composition of the optimum medium for the highest lipase production was 2.0% glycerin, 1.0% corn steep liquor, 2.0% yeast extract, 0.1% $MgSO_4$ $7H_2O$, 0.2% $K_2HPO_4$, 1.5% soybean oil and 0.1% LAS(linear alkylbenzene sulfonate) with initial pH value of 10.0 and 3-day cultivation at $25^{\circ}C$. The lipase activity of the strain J-19 under optimal condition was 3.3. units/ml, which was increased about 1.3-fold than that of basal medium.

• Advances in nano research
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• 제12권5호
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• pp.457-465
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• 2022

The potentials of Ni_xZn_1-xFe₂O₄ (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) nanoadsorbents were investigated for removal of Cd and Cr from contaminated water from an electroplating industry in Himachal Pradesh, India. Optimal values were recorded under batch adsorption experiments performed to remove dissolved heavy metal ions from industrial wastewater. The specific surface area (SSA) of nanoadsorbents perceived to vary in a range 35.75-45.29 cm²/g and was calculated from the XRD data. The influence of two operating parameters, contact time and dopant (Ni) concentration was also investigated at pH ~7 with optimum dosage. Kinetic studies were conducted within a time range of 2-10 min with rapid adsorption of cadmium and chromium ions onto Ni_0.2Zn_0.8Fe₂O₄ nanoadsorbents. Pseudo-second-order kinetic model was observed to be well fitted with the adsorption data that confirmed the only existence of chemisorption throughout the adsorption process. The maximum adsorption efficiency values observed for Cd and Cr were 51.4 mg/g and 40.12 mg/g, respectively for different compositions of prepared series of nanoadsorbents. The removal percentage of Cd and Cr was found to vary in a range of 47.7%-95.25% and 21%-50% respectively. The prepared series of nanoferrite found to be suitable enough for adsorption of both heavy metal ions.

• Membrane and Water Treatment
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• 제2권3호
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• pp.137-145
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• 2011

Membrane processes are major breakthrough for the removal of organic pollutants in water remediation. The separations of solutes depend on nature of the membranes and solutes. The separation performance depends on the nature of the solutes (i.e., molecular volume, polarity, and hydrophobicity) for the same membrane. As 4-chlorophenol is of more dipolemoment compared to 2-chlorophenol, the orientation of the molecule enables it pass through the pores of the membrane, which is of negatively charged and thus separation order follows: 2-chlorophenol > 4-chlorophenol. Hydrophobicity factor also supports the order. Addition of sodium dodecyl sulfate (SDS) to chlorophenol solution shows remarkable increase in separation performance of the membrane. The improvement in separation is 1.8 and 1.5 times for 4- and 2- chlorophenol consecutively in case of 0.0082 M SDS (1cmc = 0.0082 M) in the solution. 4-chlorophenol has better attachment tendency with SDS because of its relatively more hydrophobic nature and thus reflects in performance i.e. the separation performance of 4-chlorophenol with SDS through the membrane is better compared to 2-chlorophenol.

• Magazine of the Korean Society of Agricultural Engineers
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• 제32권4호
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• pp.45-52
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• 1990

Government has propelled strongly the Agricultural - cum - Industrial region development project in the nation wide. This project will not only provide employment opportunity for rural inhabitants, but also be designed to activate the rural economy. In addition, it will lead to a balanced development between the urban and rural areas. Under this project, building sites of 3 to 30 hactres will be established in the rural area in order to settle factories which are suitable to the rural condition. In this report, the researches which relating to the achievement conditions of planning, design and constructions of the building sites and the contribution conditions of Agri. - cum - Industrial Region development projects, activated to the rural economy and regional development in the Kyungpook regional areas, were surveyed and studied. On the average evaluation studies the results are as follows : 1. The achievement conditions of the planning, design and construction of the building sites. Very good 27.0 % Good 47.0 % Fair 24.0 % Poor 2.0 % 2. The contribution conditions of the Agri - cum - Industrial factories managements. Very good 17.0 % Good 41.0 % Fair 32.0 % Poor 10.0 %

• Journal of Environmental Health Sciences
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• 제16권2호
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• pp.1-10
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• 1990

This study was performed to evaluate a applicability of TCM(Texas Climatological Model) model to a industrial area sush as CUNSAN and a possibility to provide necessary informaitons for air quality management. The air pollutants were measured at 6 sampling sites of GUNSAN industrial area from june to july in 1989. The model was checked by comparing the observed data with estimated data. The meteorological data for wind direction and wind speed were obtained from the observatory station in GUNSAN. The results are summarized as follows. 1. Average concentrations of air pollutants at all sampling sites were SO$_{2}$ 0.011-0.019 ppm. NO$_{2}$ 0.012-0.017 ppm. CO 0.6-1.0 ppm. TSP 45.8-64.2 $\mu$g/m$^{3}$. 2. The emission amounts show that point source are in general higher than area source. 3. As a results of correlation analysis, relationship between SO$_{2}$ concentration in the observed value and estimated value showed positive significance.(r = 0.766) 4. The sulfer content of the 1.6% at present to 0.8%, which means a 53.3% reduction. By controlling stack height could be lowered 14.5%, but the effective way of emission control is use of the lower sulfer fuels than controlling stack height. 5. The ratio between SO$_{2}$ contration in the observed value and estimated value showed 1.05. There-fore, the TCM model was quite effective in predicting air quality in GUNSAN industrial area.

• Journal of dental hygiene science
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• 제7권3호
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• pp.179-185
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• 2007

The purpose of this study targeted on high school student in the department of liberal arts, industry in Daegu metropolitan city, is to get basic data necessary for the development of dental educational program, to discern prevention and treatment of temporomandibular joint disorder by observing the situation temporomandibular joint disorder and contribution element, of relationship of school life stress The results are as follows.: 1. The percentage of occurring temporomandibular joint disorder in the high school resulted in a joint noise at 61.8% and joint dislocation 6.9%, sharp pain 47.5% at time of chewing. 29.8% at the time of the non-chewing, lockjaw 11.3%, a headache appeared at 40.4%.2. In the contribution factor of occurring temporomandibular joint disorder, the cause of joint noise was the clench one's teeth, lip and cheek clench, For the pain at the time of chewing clench one's teeth, one side chewing, over-chewing, lip clench, sideways sleeping showed the difference. (P < 0.01) For the pain at the time of non-chewing, clench one's teeth, bruxism, one side chewing, lip and cheek clench were similar, and for the lockjaw, clench one's teeth, bruxism, sideways sleeping showed the difference. The plum evil thing period at time of the fault writing that statistically showed the difference. For the headache, the contribution factors were the all bad habits mentioned above excluding one side sleeping.(P < 0.01, P < 0.05). 3. The rate of experiencing temporomandibular joint disorder by oral and maxillofacia was 13.4% in industrial department, and 19.6% in liberal arts. And for the factor of wound was that exercise 26.8%, others 24.4%, fall-down 19.5%. And for the industrial, exercise 44.4%, fall-down 22.2%, others 14.9%. The treatment experience appeared at 5.0% in industrial department, 2.9% in liberal arts. And for the medical institutions, liberal arts were dental clinic 50%, orthopedics 50%, and the industrial department orthopedics 40%, oriental medicine clinic 30%, dental clinic 30%. 4. In case of temporomandibular joint disorder, there were no difference by grades or educational background. And at the time of chewing or non-chewing showed similar difference.(P < 0.01). 5. Compared to stress in the high school, it generally showed higher in liberal arts than in industrial department due to school record. Its scope was $3.75{\pm}1.14$ in liberal arts, $3.01{\pm}1.23$ in industrial department. 6. The school record, school life, stress problems by teachers, chewing/non-chewing pain of temporomandibular joint disorder, joint noise had a similar correlation.(P < 0.01, < 0.05).

• Environmental and Resource Economics Review
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• 제15권4호
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• pp.643-672
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• 2006

This study has assessed the industrial human toxicity index by means of toxic substances emissions in South Korean industry. The data used in analysis are the 146 kinds of the toxic chemicals emissions and final demands, total outputs in the input-output table. As a results, human carcinogenic index was $11.86198{\times}10^3$ for overall industries, and $0.26360{\times}10^3$ for average. The industries of higher human toxicity index can be ranked as follows: Mother vehicles and parts (7.85033) > Pig iron and crude steel(4.57409) > Primary iron and steel products(4.36668) > Other transportation equipments and parts(3.43293) > Inorganic basic chemical products(2.64379), etc. Such result can be considered as the priority order of regulation based on industrial characteristics, when the demand and industrial policies should be carried out for the deduction fof toxic substances.

• Korean Journal of Materials Research
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• 제31권12호
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• pp.672-676
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• 2021

In this paper, the effect of Ni (0, 0.5 and 1.0 wt%) additions on the microstructure, mechanical properties and electrical conductivity of cast and extruded Al-MM-Sb alloy is studied using field emission scanning electron microscopy, and a universal tensile testing machine. Molten aluminum alloy is maintained at 750 ℃ and then poured into a mold at 200 ℃. Aluminum alloys are hot-extruded into a rod that is 12 mm in diameter with a reduction ratio of 39:1 at 550 ℃. The addition of Ni results in the formation of Al₁₁RE₃, AlSb and Al3Ni intermetallic compounds; the area fraction of these intermetallic compounds increases with increasing Ni contents. As the amount of Ni increases, the average grain sizes of the extruded Al alloy decrease to 1359, 536, and 153 ㎛, and the high-angle grain boundary fractions increase to 8, 20, and 34 %. As the Ni content increases from 0 to 1.0 wt%, the electrical conductivity is not significantly different, with values from 57.4 to 57.1 % IACS.