• Safety and Health at Work
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• v.1 no.2
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• pp.175-182
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• 2010

Objectives: This study examined how ethanolamines (EAs) with the same functional alcohol group ($HOCH_2CH_2$), such as mono-EA (MEA), di-EA (DEA), and tri-EA (TEA), in water-based metalworking fluids (wbMWFs) are vaporized, condensed, and transformed by heat generated during metalworking. Methods: Two types of experimental apparatus were manufactured to achieve these objectives. Results: Vaporization tests using a water bath showed that the vaporization rate increased markedly from $0.19\;mg/m^2{\cdot}min$ at $23.5^{\circ}C$ to $8.04\;mg/m^2{\cdot}min$ at $60^{\circ}C$. Chamber tests with a heat bulb revealed that "spiked" MEA was fully recovered, while only 13.32% of DEA and no TEA were recovered. Interestingly, non-spiked types of EAs were detected, indicating that heat could convert EAs with more alcohol groups (TEA or DEA) into other EAs with fewer group(s) (DEA or MEA). The EA composition in fresh fluid was 4% DEA, 66% TEA, and 30% MEA, and in used fluids (n = 5) was 12.4% DEA, 68% TEA, and 23% MEA. Conversion from TEA into DEA may therefore contribute to the DEA increment. Airborne TEA was not detected in 13 samples taken from the central coolant system and near a conveyor belt where no machining work was performed. The DEA concentration was $0.45\;mg/m^3$ in the only two samples from those locations. In contrast, airborne MEA was found in all samples (n = 53) regardless of the operation type. Conclusion: MEAs easily evaporated even when MWFs were applied, cleaned, refilled, and when they were in fluid storage tanks without any metalworking being performed. The conversion of TEA to DEA and MEA was found in the machining operations.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.517-524
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• 2014

Two key technologies of horizontal drilling and hydraulic fracturing are recognized to achieve the rapid growth of shale gas production, in specific, in the United States during last decade. The claims between environmentalists and oil companies have been debating in terms of water contamination. Nowadays, voluntary publication of chemicals from shale gas players are available in the website, FracFocus. This paper introduces chemicals that are currently used in hydraulic fracturing process. Among chemicals, guar gum and guar derivatives are dominantly consumed to increase the viscosity of hydrofracking fluids. The role of additional additives, such as breakers and biocides, is presented by explaining how they cut down the molecular structure of guar gum and guar derivatives. In addition, crosslinking agent, pH controller, friction reducer, and water soluble polymers are also presented.

• KSBB Journal
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• v.18 no.5
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• pp.393-397
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• 2003

The effect of corrosion inhibitors on antimicrobial activity of biocides (Kathon 886 MW, Triadine 3, Triadine 10 and Grotan BK) was investigated using the Pseudomonas aeruginosa which frequency of occurrence in contaminated fluids is very high and its growth and survival is excellent. When a biocide was used with a corrosion inhibitor, the antimicrobial activity of it was affected by the corrosion inhibitor used. The antimicrobial activity of Kathon 886 MW increased when corrosion inhibitor (each of SS 510, MEA) was used. Triadine 3, Triadine 10, Grotan BK showed the similar trend of antimicrobial effect for the corrosion inhibitors used. Their antimicrobial activities increased when the corrosion inhibitor such as CP-105, CP-E-7 and MEA was used individually. The antimicrobial activity of each corrosion inhibitor was also compared. The results showed that CP-E-7 and MEA was bioresistant and the other corrosion inhibitors were biosupportive. The antimicrobial activity of biocides was in the order of Triadine 10 < Triadine 3 < Kathon 886 MW < Grotan BK.

• Journal of Korea Soil Environment Society
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• v.1 no.1
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• pp.67-79
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• 1996

Clay soils typically have low hydraulic conductivities in the presence of high polarity pore fluid, such as water. Low polarity fluids, such as hydrocarbon fuels and halogenated organic solvents, typically cannot migrate into clay pores because they cannot displace the pore water. Oxygenated additives in gasoline, such as alcohols and methyl-tert-butyl ether, are increasingly used to control air pollution emissions. These relatively polar and highly water-soluble compounds may facilitate displacement of pore water and enhance migration of fuels and solvents through clay-rich soil strata. In the reported research, the migration of gasoline-alcohol fuel mixtures (gasohol) through consolidated clay was examined. Prepared kaolinite clay samples were consolidated from slurry, and various combinations of gasoline, alcohol, and water were applied to the clays under 152 Pa gauge pressure. Movement of the fluids into the clay samples was monitored by measur ing displaced pore fluid and by magnetic resonance imaging of the samples. The structures of selected samples were examined using environmental scanning electron microscopy. Results of the research suggest that alcohol added to hydrocarbon fuels can enhance migration through some clays significantly. Gasoline did not migrate appreciably into water saturated clay, even after 14 days under pressure. The gasohol mixture migrated readily into the clay in only 20 minutes. Increased hydraulic conductivity of the clay in the presence of gasohol is hypothesized to be due to the collapse of the clays pore structure when ethanol is present, creating larger pores. Increasing pore diameter decreases the capillary pressure needed for the gasohol to replace water and allows gasohol to migrate through the clay.

• Journal of The Korean Society of Clinical Toxicology
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• v.6 no.1
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• pp.49-51
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• 2008

Sodium azide (NaN3) is a white to colorless, crystalline powder that is highly water soluble, tasteless, and odorless. It is used mainly as a preservative in aqueous laboratory reagents and biologic fluids and also as an automobile airbag gas generant. Although it has caused deaths for decades, the toxic properties and effects of sodium azide in humans remains unknown. A 31-year-old comatose female was transported to the emergency department with an empty bottle labeled sodium azide. She developed cardiac arrest 15 minutes after arrival and expired in spite of 30 minutes of resuscitative effort. Subsequently, resuscitation team members incidentally suffered from sodium azide's exposure and developed eye discomfort, skin rashes parasthesias, pruritus, sore throat, and headache.

• Applied Chemistry for Engineering
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• v.16 no.6
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• pp.834-841
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• 2005

Polyethylene glycol esters (PEG-esters) were synthesized by condensation reaction of dicarboxylic acid such as adipic acid and sebacic acid and several PEGs. The PEG-esters were analyzed by FT-IR, $^1H-NMR$ and HPLC for structure analysis, and by GPC for molecular weight. Through the analysis of surface tension, critical micelle concentration (CMC), aluminum contact angle of water solution containing the PEG-ester, the synthetic PEG-esters are proven to exhibit surfactant properties. The surface tension ranged from 45 to 50 dyn/cm depended on the concentration and structures of the PEG-esters. The surface tension of PEG-esters with sebacic acid moiety and short polyoxyethylene unit resulted in lower value than that of PEG-ester with adipic acid moiety and long polyoxyethylene unit. The CMC of water solution containing 2.5 wt% PEG-ester with sebacic acid moiety estimated at $0.9{\times}10^{-5}{\sim}5.3{\times}10^{-3}mol/L$ depended on the structures of PEG-esters. The CMC of PEG-esters with long polyoxyethlene unit showed a higher value than that of PEG-esters with short polyoxyethylene unit. Meanwhile, the CMC of PEG-esters with adipic acid moiety was not distinct due to their high hydrophilic character. As the results of contact angle and cutting time aginst aluminum, the contact angle ranged from $45^{\circ}$ to $53^{\circ}$ depended on the concentration of PEG-esters. The cutting time of aluminum showed the shortest value at CMC, but the longest value above CMC. This fact indicates that the CMC of PEG-esters is a very important factor in drilling aluminum.

• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.487-494
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• 2005

Nowadays a large amount of wastewater containing metal working fluids and cleaning agents is generated during the cleaning process of parts working in various industries of automobile, machine and metal, and electronics etc. In this study, aqueous or semi-aqueous cleaning wastewater contaminated with soluble or nonsoluble oils was treated using ultrafiltration system. And the membrane permeability flux and performance of oil-water separation (or COD removal efficiency) of the ultrafiltration system employing PAN as its membrane material were measured at various operating conditions with change of membrane pore sizes and soil concentrations of wastewater and examined their suitability for wastewater treatment contaminated with soluble or insoluble oil. As a result, in case of wastewater contaminated with soluble oil and aqueous or semi-aqueous cleaning agent, the membrane permeability increased rapidly even though COD removal efficiency was almost constant as 90 or 95％ as the membrane pore size increased from 10 kDa to 100 kDa. However, in case of the wastewater contaminated with nonsoluble oil and aqueous or semi-aqueous cleaning agent, as the membrane pore size increased from 10 kDa to 100 kDa and the soil concentration of wastewater increased, the membrane permeability was reduced rapidly while COD removal efficiency was almost constant. These phenomena explain that since the membrane material is hydrophilic PAN material, it blocks nonsoluble oil and reduces membrane permeability. Thus, it can be concluded that the aqueous or semi-aqueous cleaning solution contaminated with soluble oil can be treated by ultrafiltration system with the membrane of PAN material and its pore size of 100 kDa. Based on these basic experimental results, a pilot plant facility of ultrafiltration system with PAN material and 100 kDa pore size was designed, installed and operated in order to treat and recycle alkaline cleaning solution contaminated with deep drawing oil. As a result of its field application, the ultrafiltration system was able to separate aqueous cleaning solution and soluble oil effectively, and recycle them. Further more, it can increase life span of aqueous cleaning solution 12 times compared with the previous process.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.4
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• pp.673-679
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• 1992

To investigate the effects of molasses addition at ensiling on nutritional quality of wilted napier grass, chemical quality and nutrient composition of the silages, digestibility and nitrogen retention at feeding trials were analysed using 4 goats in a cross over design. The results are as follows : 1. Molasses addition at ensiling decreased pH value (3.99) and ammonia nitrogen, and increased lactic acid content by 285% compared to non-additive silage (83.5 g/kg dry matter). 2. There were no differences in digestibilities of dry matter, crude protein, neutral detergent fiber, acid detergent fiber, hemicellulose and cellulose between the silage ensiled with molasses (MS silage) and the silage ensiled without molasses (WS silage). Urinary nitrogen excretion, however, significantly (p<0.05) decreased in goats fed the MS silage, and nitrogen retention was positive in goats fed the MS silages, but negative in goats fed the WS silage. 3. Acetic acid concentration in remained fluids in goats fed the MS silage was lower and propionic and butyric acid concentrations were higher than those in goats fed the WS silage. As water soluble carbohydrate content was higher in the MS silage than in the WS silage, a part of added molasses was still remained in the silage at the feeding trials and could be utilized for energy sources by the goats. Nitrogen may be also effectively utilized in goats fed the MS silage, because the silage were inhibited in proteolysis during ensiling.

• Archives of Pharmacal Research
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• v.21 no.6
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• pp.645-650
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• 1998

The dual drug-loaded alginate beads simultaneously containing drug in inner and outer layers were prepared by dropping plain (single-layered) alginate beads into $CaCl_2$ solution. The release characteristics were evaluated in simulated gastric fluid for 2 h followed by intestinal fluids thereafter for 12 h. The surface morphology and cross section of dual drug-loaded alginate beads was also investigated using scanning electron microscope (SEM). The poorlv water-soluble ibuprofen was chosen as a model drug. The surface of single-layered and dual drug-loaded alginate beads showed very crude and roughness, showing aggregated particles, surface cracks and rough crystals. The thickness of dual drug-loaded alginate beads surrounded by outer layer was ranged from about 57 to 329mcm. The distinct chasm between inner and outer layers was also observed. In case of single-layered alginate bead, the drug was not released in gastric fluid but was largely released in intestinal fluid. However, the release rate decreased as the reinforcing $Eudragit^{\circledR}$ polymer contents increased. When the plasticizers were added into polymer, the release rate largely decreased. The release rate of dual drug-loaded alginate beads was stable in gastric fluid for 2 h but largely increased when switched in intestinal fluid. The drug linearly released for 4 h followed by another linear release thereafter, showing a distinct biphasic release characteristics. There was a difference in the release profiles between single-layered and dual drug-loaded alginate beads due to their structural shape. However, this biphasic release profiles were modified by varying formulation compositions of inner and outer layer of alginate beads. The release rate of dual drug-loaded alginate beads slightly decreased when the outer layer was reinforced with $Eudragit^{\circledR}$ RS1OO polymers. In case of dual drug-loaded alginate beads with polymer-reinforced outer layer only, the initial amount of druc released was low but the initial release rate (slope) was higher due to more swellable inner cores when compared to polymer-reinforced inner cores. The current dual drug-loaded alginate beads may be used to deliver the drugs in a time dependent manner.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.6
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• pp.609-615
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• 2008

In this study, the design of UV-free reflecting reactor was studied to enhance the cutting fluid life for cutting machine. And also, the stability of cutting fluid with addition of biocide in cutting fluid and without biocide was compared with respect to the cutting fluid concentration, pH changes and microorganisms. Low number of microorganism was observed in the cutting fluid after UV-free reflecting treatment as compare to the cutting fluid which was added biocide and just cutting fluid alone. PH of the cutting fluid after UV-free reflecting treatment was about 9$\sim$8.5 while others were observed considerably low. The oil contents of cutting fluid which was added biocied and pure cutting fluid were almost degraded with the passage of time. However, in case of UV-free reflecting reactor, 4$\sim$3.5 Brix oil contents were observed in the cutting fluid.