• Journal of the Korean Society of Safety
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• v.20 no.2 s.70
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• pp.98-104
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• 2005

Saw dust concrete f3r finding out insulation characteristic was tested using test plate $30cm{\times}30cm{\times}5cm$. basically, molds f3r the test of compressive, tensile, normal without sawdust, $0.05\%,\;0.1\%,\;0.2\%,\; 0.4\%,\;0.6\%,\;0.8\%,\;1.0\%,\;1.2\%,\;1.4\%,\;1.6\%,\;1.5\%,\;2.0\%$, mixing proportion. heat conductivity of the saw dust concrete mixed with the above proportion was taken in this study. Thermal conduction of normal concrete depends on mixing proportion strength aggregate character, water content. all these items are specified here in fables. $1.8\%\~2.0\%$ saw-dust mising concrete shows as the faction as normal insulation material has its function. and the higher saw-dust mixing rate becomes, the thermal conduction becomes the less Then, the conclusions are that saw-dust using concrete has better insulation function than normal concrete.

• Korean Journal of Human Ecology
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• v.22 no.6
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• pp.687-699
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• 2013

This study was carried out to investigate the antifungal activity and house dust mite repellent effect of cotton and silk fabrics dyed with Juniperus chinensis heartwood extracts by hot-water and methanol. The chemical composition of Juniperus chinensis heartwood extracts by hot-water and methanol was analyzed by GC-MS. In the case of antifungal activity, dyed fabrics with hot water extract had no effect against chaetomium globosum fungus. But showing no growth in fabrics dyed with methanol extract, dyed fabrics with methanol extract showed very excellent antifungal activity. Silk fabric dyed with methanol extract showed excellent house dust mite repellent effect of 94.3%~96.0% against dermatophagodes farinae. The composition of Juniperus chinensis heartwood extracts from hot-water and methanol was different. There were no terpene and its analogue peaks in hot-water extract. However there were terpene and its analogue peaks in methanol extract. From these GC-MS results, terpene was identified in methanol extract of Juniperus chinensis heartwood. Efficient ingredient of antifungal activity and house dust mite repellent effect was assumed terpene.

• KIEAE Journal
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• v.9 no.1
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• pp.55-60
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• 2009

This study was carried out to propose the optimum technologies that can be applicable to noise and fugitive dust controlling in construction sites by comparative analysis in cases. The ninety three environmental management technologies applied to fifty-five construction projects conducted during 2005~2007 in Korea were analyzed by checklist method. The construction companies paid more attention to the noise and fugitive dust controlling technologies than the waste and wastewater. The diverse pollution controlling techniques were applied to the architectural projects than the civil projects to meet the environmental requirements in residential area. The fugitive dust controlling technologies(75.3%) were more widely applied to all construction projects than the noise controlling technologies(24.7%). As the noise controlling techniques, the noise barriers in wall-form which are set up as boundary in construction site were more widely used than the noise barriers in curtain-form, in cabin and silencers. Water spraying systems, wind barriers and mechanical sweepers were the preferred technologies for controlling fugitive dust emission.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.157-163
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• 2011

Combustion of magnesium dust particle were fabricated test devices and combustion experiments were carried out. The ignition delay time were measured in change of magnesium particle mass flow rate in premixed flame. According to increasing magnesium particle mass flow rate, ignition delay time were more shorter. In addition, magnesium dust combustion temperature were measured different particle sizes and o/f ratio by two wavelength pyrometry. Dust combustion flame temperature is almost similarly, through to equivalence ratio, confirm the combustion flame temperature range characteristics.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.10 no.1
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• pp.104-114
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• 2000

This study was carried out to estimate current status of dust concentrations in the factories producing non-metallic products in Korea. Data were gathered from the environmental monitoring reports by 40 workplace environmental monitoring institutes and the questionnaire designed for the study by the authors. A total of 1838 dust samples from 368 plants were obtained from the reports and were analyzed with no data modifications. But data on asbestos, rock wool, and welding fumes were excluded in this evaluation. The factories were classified into eight groups according to the standard industrial classification scheme in Korea. The results of this study were as follows; 1. The factories included were glass, non-refractory ceramic, refractory ceramic ware, structural non-refractory clay and ceramic, cement and lime, articles of concretes, and stone. Mean(geometric mean) concentrations of total dust samples ranged from $1.75(0.84)mg/m^3$ to $5.87(2.84)mg/m^3$. Statistically significantly higher dust concentrations were found in the cement and lime industries compared with other industries. 2. The non-compliance rates were 15.2% in glass and 20.6% in other non-metallic mineral products industries. Although all institutions surveyed utilized the identical sampling and classification scheme for dusts as specified in the current occupational exposure limits, wide discrepancies were found in collecting samples and classifying dusts. Further problems were discovered in classifying dusts. A dust sample collected could be classified into any of the three groups regardless of silica content. The results of this study showed that dust concentrations in the non-metallic products industries varied widely. Also discovered was classification errors of dust types among workplace monitoring institutes. These errors could adversely affect the results of exposure assessments and the true nature of dust hazards. Further, no institutions performed respirable dust sampling and analysis of crystalline silica. In order to correct these malpractices, current standards of occupational exposure limits should be revised and tight supervision by the Ministry of Labour be suggested.

• Journal of the Korean Society of School Health
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• v.18 no.1
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• pp.15-25
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• 2005

Purpose: Recently there are scientific evidences for the health effects of Asian dust-storms. Particularly in 2002, the daily average of $PM_10$ exceeded 600 and 700 $\mu{g}/m^3$ in March and April respectively. We examined the effects of Asian dust‐storms on perceived symptoms and preventive behaviors among children, adults, and elders. Method: The subjects of this study were 425 children, 444 adults and 60 elders. A questionnaire survey was carried out on the children and the adults by teachers and on the elders by interviewers to obtain information on demographic variables, perceived symptoms and preventive behaviors, previous respiratory disease, environmental tobacco smoke, and proximity between the house and the road during Asian dust-storms. We analyzed using descriptive statistics, $X^2$ test and multiple logistic regression models. After adjustment for potential confounders, we estimated the odds ratios and 95% confidence intervals of the children and the elders for perceived symptoms and preventive behaviors. Result: The elders had a significantly higher prevalence of respiratory symptoms than the other groups. The children had a significantly higher prevalence than the adults in getting URI (1.51), coughing (1.68), rhinorrhea (1.46), fever (2.39) and medication for allergy or asthma (1.90). The children had better behaviors than the elders in closing windows (3.57), taking less outdoor recreational activity (2.59) and staying home (2.60). Conclusion: This study suggested that children and elders are susceptible to the effects of Asian dust on health. Health educators should inform these populations about the influence of Asian dust and provide health education for preventive behaviors.

• Journal of the Korean Society of Safety
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• v.19 no.1
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• pp.137-140
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• 2004

The minimum ignition temperature at which the dust cloud can spontaneously ignite is considered to be very important in industries to prevent explosion occurring in hot surfaces. This paper has dealt with the experimental study of the determination of minimum ignition temperature of Hydroxy Propyl Methyl Cellulose (HPMC) dust cloud. We have used the Godbert-Greenwald Furnace Apparatus to determine the ignition temperature and limiting oxyten concentration for dust could. The experimental determinations on the minimum ignition temperature were carried out with various particle size with nominal diameters 45, 75 and 106${\mu}m$. The limiting oxygen concentration of dust cloud was determinated for the smaller size(45${\mu}m$) HPMC. Minimum ignition temperature of dust cloud was at 364$^{\circ}C$ for the concentration of 2.5g/L in the air and became higher with the increasing of nitrogen concentration. It was also found that the ignition didn't occur when the oxygen concentration was below 10%, and limiting oxygen concentration is at 11%.

• Resources Recycling
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• v.26 no.3
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• pp.17-25
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• 2017

Electric arc furnace steelmaking dust has various physicochemical properties as volatile components generated in the melting process of steel scraps in an electric arc furnace, which is captured in oxide form as fine powder by reacting with oxygen in the air. In order to efficiently recycle these electric arc furnace dust, a kinetic basic experiment and a pilot production test were carried out in parallel. As a result, it was found that the electric arc furnace dust contain a large amount of Cl and alkali components, thus it was expected that the compounds have a great adverse effect on the actual operation for the recycling. It was confirmed that the volatilization behavior was progressing actively at $1100^{\circ}C$ and the electric arc furnace dust was melted at $1250^{\circ}C$. These results are the same as a result of pilot test for the formation behavior of zinc oxide and reduced iron. These results should be useful as basic data for designing the recycling plant of the electric arc furnace dust and establishing the operating conditions.

• The Journal of Engineering Geology
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• v.17 no.2 s.52
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• pp.279-287
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• 2007

An ore of stone obtained from quarry lose its about 60% such as the muck and the stone-dust during the process of making the architectural block, the crushed aggregate and so on. A part of the muck is only reutilized for the crushed aggregate as road pavement materials, while the most of the muck in the shape of powder is mixed with water and then it is deposited in a sludge tank. The muck in the shape of powder is called the stone-dust. If the stone-dust is discharged and sprayed, an ecosystem will have terrible damage because the seepage of surface water, the flow of ground water and the movement of air are not occurred smoothly by packing the void of soils. As the Waste Management Law (2003) in Korea, the stone-dust is sorted out the industrial waste and the most of that is dumped in ground. Therefore, the establishments of an efficient recycling plan are necessary through the improvement of engineering properties of the stone-dust. To investigate the possibility of recycle and improvement for the stone-dust, the stone-dust and natural soils are sampled from six quarries in Korea. The various soil tests are performed by use of the mixed soils with the stone-dust content ratio. As the result of various soil tests, the recycle possibility of the stone-dust is analyzed as subbase layer materials of the roads.

• Applied Chemistry for Engineering
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• v.10 no.8
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• pp.1104-1108
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• 1999

In this study it was focused that if the chrome could be removed in the shaving dust, the reusable protein resource could be recycled from the shaving dust. As the chrome forms a Cr-collagenate by cross linking of collagen in the shaving dust, the dust was steeped for swelling and plumping by $Ca(OH)_2$ solution and then chromium in dust was resolved out by $H_2SO_4$ solution in the first stage process. In the second stage one, dust was swelled and plumped by NaOH solution and then the chromium in dust was oxygenated to a hexavalent chrome, which has high solubility in $H_2O_2$ solution. And then the chromium was removed byt he steeping of $H_2SO_4$ solution as the last process. The first stage process was consisted of the sequential steeping of 3%-$Ca(OH)_2$ and $0.8%-H_2SO_4$. In the second stage the total chrome was effectively removed by the sequential steeping of 0.1%-NaOH, $3%-H_2O_2$ and $1%-H_2SO_4$. In the completely dechromated dust, the humidity was measured as 10.68% and the crude protein was contained by 79.81%. Steeping solutions were reused 3 times for chrome removal process, the chrome was entirely removed in shaving dust.