• 한국산업보건학회지
• /
• 제3권1호
• /
• pp.91-98
• /
• 1993

This study was carried out to investigate characteristic of vinyl chloride emissioned from poly vinyl chloride extrusion process and to evaluate the efficiency of local exhaust ventilation system. Before local ventilation facility was constructed in poly vinyl chloride extrusion process, the average worker exposure to vinyl chloride was 3.15 ppm, which exceeded Threshold Limit Value of American Conference of Gorvernmental Industrial Hygienists (ACGIH-TLV), 1 ppm. lt is possible that vinyl chloride residues in the poly vinyl chloride resin was released or degased due to extrusion heat. The larger the width of vinyl tube become, the higher worker exposure to vinyl chloride was. It is estimated that vinyl chloride from vinyl chloride resin increased as amount of poly vinyl chloride resin extruded in the extrusion process increased. Canopy hood was an appropriate type for poly vinyl chloride resin extrusion process. This local exhaust ventilation has fan static pressure of 7.65 inch wg($190mmH_2O$, total volumetric flowlate of 4,796 CFM ($135.8m^3$/min) and fan power requirement of 12 hp (8.952 Kw). After this local exhaust ventilation was constructed there, the average concentration of worker exposure to vinyl chloride was reduced to be 0.46 ppm, which was below the Threshold Limit Value, 1 ppm. Also, the removal efficiency rate of vinyl chloride attained by local exhaust ventilation was 85.3%. It was a statistically significant (p<0.01).

• 한국환경과학회지
• /
• 제21권3호
• /
• pp.377-382
• /
• 2012

Recent research has demonstrated that treating poultry litter with alum (aluminum sulfate) and aluminum chloride can remove environmental threats (ammonia, soluble phosphorus and odor) posed by litter. However, scientific information available on heavy metal in poultry litter with liquid aluminum chloride is still lacked. The purpose of this study was to investigate the effects of applying liquid aluminum chloride to rice hulls on heavy metals and to provide basic information to producers. Six hundred 0-d-old broiler were assigned to 4 treatments (control, 100 g, 200 g and 300 g of liquid $AlCl_3$/kg of rice hulls, respectively) with 3 replicates of 50 birds. The experimental period lasted for 6 weeks. Liquid $AlCl_3$ was sprayed on the rice hulls surface using a small hand pump. Total Al contents increased (P<0.05) with the increasing levels of liquid $AlCl_3$ levels over time in comparison with control groups. Total Cu and Pb were lowered in all liquid $AlCl_3$ treatments compared with the controls during 6 weeks. Significant differences in all treatments were found for total Cu contents at 2, 3 and 5 weeks and total Pb at 0, 1, 2 and 3 weeks. Total Zn contents decreased with time when compared with controls. However, no significant differences in total Zn contents were observed among all treatments. In light of environmental managements, spraying liquid $AlCl_3$ to rice hulls indicated the significant advantages in reducing heavy metals as well as improving poultry industrial competitiveness.

• 한국안전학회지
• /
• 제30권4호
• /
• pp.120-127
• /
• 2015

The aim of the present study is to investigate some characteristics of concrete according to addition of blast furnace slag and alkali-activator dosages. Blast furnace slag was used at 30%, 50% replacement by weight of cement, and liquid sulfur having NaOH additives was chosen as the alkaline activator. In order to evaluate characteristics of blast furnace slag concrete with sulfur alkali activators, compressive strength test, total porosity, chloride ions diffusion coefficient test were performed. The early-compressive strength characteristics of blast furnace slag concrete using a sulufr-alkali activators was compared with those of reference concrete and added 30, 50% blast furnace slag concrete. Also, Blast furnace slag concrete using sulfur-alkali activators enhanced the total porosity, chloride ions diffusion coefficient than two standard concrete. Alkali-activated blast furnace slag concrete was related to total porosity, compressive strength and chloride ions diffusion coefficient each others. As a result, it should be noted that the sulfur-alkali activators can not only solve the demerit of blast furnace slag concrete but also offer the chloride resistance of blast furnace slag concrete using sulfur alkali activators to normal concrete.

• 공업화학
• /
• 제18권3호
• /
• pp.251-254
• /
• 2007

실온에서 베니어에 ammonium chloride, ammonium sulfate, monoammonium phosphate, 그리고 diammonium phosphate와 같은 암모늄염으로 도포하고, 도포된 베니어의 난연성을 조사하였다. 암모늄염으로 도포된 베니어판은 미처리된 순수 베니어판에 비하여 $CO/CO_2$비를 증가시켰다. 이것은 정도에 따라 독성에 영향을 미치는 것으로 생각된다. 암모늄염이 베니어의 난연제로 사용되었을 때, 도포된 암모늄염은 베니어의 난연성을 향상시켰다. 또한 ammonium sulfate와 ammonium chloride로 도포된 베니어는 미처리된 순수 베니어에 비해 양쪽 모두 낮은 총연기방출율과 낮은 총연기량을 나타내었다.

• 한국식품위생안전성학회지
• /
• 제9권4호
• /
• pp.229-235
• /
• 1994

It is very important to investigate the sanitary chemical conditions of farmwaters used for cattle breeding in the dairy farms. For this purpose we examined pH, KMnO4 consumption, total hardness, chloride, sulfate, NH3-N, NO3-N, fluoride, lead, iron, manganese, cadmium, copper, zinc and chrome in the farmwaters sampled 2 times(spring and summer)in Choongcheongnam and Kangwon Province. The pH of farmwaters in Choongcheongnam and Kangwon Province was 6.49$\pm$0.09, 6.70$\pm$0.06, total hardness 90.21$\pm$7.07, 64.53$\pm$6.38 mg/ι, consumption of KMnO4 4.13$\pm$0.62, 4.34$\pm$0.26mg/ι, NO3-N 6.51$\pm$0.55, 3.61$\pm$0.58 mg/ι, chloride ion 20.51$\pm$1.99, 5.41$\pm$1.36 mg/ι and sulfate ion 6.61$\pm$1.02, 7.28$\pm$1.30 mg/ι, respectively. But NH3-N was scarcely detected. Fluoride, iron, lead, cadmium, zinc, manganese and chrome were not detected from the tested farmwaters. There was high significance between each other in total hardness, NO3-N, chloride ion and sulfate ion. There was regional and seasonal significance in only NO3-N but only regional significance in total hardness and chloride ion.

• 한국환경과학회지
• /
• 제18권7호
• /
• pp.819-824
• /
• 2009

The objectives of this study were to evaluate the effects of chemical additives on total phosphorus (TP), soluble reactive phosphorus (SRP), and total volatile fatty acids (total VFAs) in hanwoo slurry. The treatments in this study were ferrous sulfate, alum, and aluminum chloride, and applied at the rate of 0, 0.5, and 1.0 g/25 g of hanwoo slurry. All of the chemical treatments significantly lowered TP (11 to 53% of the untreated control), SRP (41 to 99.9% of the untreated control), and total VFAs (22 to 48.5% of the untreated control) by reducing hanwoo slurry pH (3.42 to 6.86). Among these chemical amendments, addition of 0.5 g ferrous sulfate, alum, and aluminum chloride to hanwoo slurry were the best results evaluated on farms with respect to reducing negative environmental impacts. In conclusion, the results of this study indicate that the use of chemical amendments should be considered in the development of best management practices (BMPs) for the hanwoo industries.

• 한국식품영양학회지
• /
• 제30권6호
• /
• pp.1286-1291
• /
• 2017

In this study, Pyracantha angustifolia (Franch.) C. K. Schneid was extracted with 70% methanol at room temperature for 48 hrs and concentrated under reduced pressure to measure its total polyphenol contents; furthermore, the effect of electron donating ability was examined. Methylene chloride, ethyl acetate, and methanol were used to fractionate the extract to testify total polyphenol contents, electron donating abilities, the removal abilities of superoxide radical as well as hydrogen peroxide. The total polyphenol contents were $2007.30{\pm}109.28{\mu}g\;GAE/mL$ in 70% methanol extract, $273.39{\pm}10.19{\mu}g\;GAE/mL$ in methylene chloride fraction, $80.57{\pm}0.64{\mu}g\;GAE/mL$ in ethyl acetate fraction, and $1,160.87{\pm}44.71{\mu}g\;GAE/mL$ in methanol fraction. The total polyphenol contents showed significant differences (p<0.05) between the solvents. The electron donating ability was $79.07{\pm}7.31%$ for 70% methanol extract, $22.34{\pm}0.64%$ for methylene chloride fraction, $5.33{\pm}0.28%$ for ethyl acetate fraction, and $32.26{\pm}1.10%$ for methanol fraction. The electron donating abilities were significantly different(p<0.05) between the solvents. The removal ability of superoxide radical was $0.018{\pm}0.003$ for 70% methanol extract, $0.007{\pm}0.002$ for methylene chloride fraction, $0.0147{\pm}0.003$ for ethyl acetate fraction, and nothing for methanol fraction. The measurement of hydrogen peroxide decomposition was $0.022{\pm}0.0046$ for 70% methanol extract, $0.0027{\pm}0.0015$ for methylene chloride fraction, $0.0037{\pm}0.0012$ for ethyl acetate fraction, and $0.0009{\pm}0.0001$ for methanol fraction.

• 한국식품영양학회지
• /
• 제31권4호
• /
• pp.543-548
• /
• 2018

This study was conducted to investigated the antioxidant activities of extract for Megmoondong fruit. Liriope platyphylla L. was extracted with 70% methanol at room temperature for 48 hr and concentrated under reduced pressure to measure its total polyphenol contents and electron donating ability. The total polyphenol contents were $7,253.50{\pm}335.43{\mu}g\;GAE/mL$ in 70% methanol extract, $1,239.77{\pm}9.30{\mu}g\;GAE/mL$ in methylene chloride fraction, $919.30{\pm}50.83{\mu}g\;GAE/mL$ in methanol fraction, $105.44{\pm}2.04{\mu}g\;GAE/mL$ in ethyl acetate fraction. The total polyphenol contents showed significant differences (p<0.05) between the solvents. The electron donating ability was $69.17{\pm}12.61%$ for 70% methanol extract, $33.11{\pm}1.77%$ for methylene chloride fraction, $5.19{\pm}2.59%$ for ethyl acetate fraction, and $20.16{\pm}1.04%$ for methanol fraction. The electron donating abilities were significantly different (p<0.05) between the solvents. The removal ability of superoxide radical was $0.0174{\pm}0.0007$ for 70% methanol extract, $0.0164{\pm}0.0007$ for methylene chloride fraction, $0.0172{\pm}0.0007$ for ethyl acetate fraction, and nothing for methanol fraction. The measurement of hydrogen peroxide decomposition was $0.0985{\pm}0.1021$ for 70% methanol extract, $0.0896{\pm}0.0893$ for methylene chloride fraction, $0.0115{\pm}0.0085$ for ethyl acetate fraction, and $0.0170{\pm}0.0180$ for methanol fraction. The Liriope platyphylla L. extracts obtained from methylene chloride showed significantly relevant results in the total polyphenol contents and electron donating ability, which was higher than the original extract.

• Nuclear Engineering and Technology
• /
• 제56권10호
• /
• pp.4254-4262
• /
• 2024

Reinforced concrete structures are subject to exposure to chloride ions in the air, leading to chloride penetration, and carbonation attacks resulting from exposure to carbon dioxide. This chemical degradation process induces corrosion of reinforcing bars within concrete, significantly impacting durability. Structures situated in coastal areas, such as nuclear power plants, are particularly susceptible to rapid chloride penetration due to the high chloride concentration in the air. This study utilizes existing experimental data to forecast the chloride diffusion coefficient employing artificial neural network (ANN technology). The total number of experimental data was 535 gathered from 18 papers. Through analysis of the chloride coefficient and predicted degradation depth, the effective cross-sectional area of concrete is examined, and the deterioration of wall performance is forecasted.

• 상하수도학회지
• /
• 제18권5호
• /
• pp.580-587
• /
• 2004

The objective of this research is to investigate the electrochemical oxidation process for nitrogen removal in wastewater involving chloride ion and nitrogen compounds. The process experiment of electrochemical oxidation was conducted by using the stainless steel tube type reactor and the $Ti/IrO_2$ as anode. Free chlorine production and current efficiency variation for total nitrogen removal was compared depending on whether electrolyte is added, and the nitrogen type distribution under an operating condition. When chloride was added as electrolyte, it was found that production of free chlorine increased and the concentration of the chloride decreased as retention time passed. The concentration of chloride in influent decreased from 1,660 to 1,198 mg/L at the current density of $6.7A/dm^2$, while concentration of free chlorine increased to 132 mg/L. Current efficiency in removal of ammonium nitrogen was increased when chloride was dosed as electrolyte. It was observed that ammonium nitrogen was oxidized to nitrite and nitrate through electrochemical oxidation and that the concentration of total nitrogen in influent was reduced from 22.58 to 4.00 mg/L at the short retention time of 168 seconds through the electrochemical oxidation of nitrogen.