• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.355-357
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• 2006

The application of specialty chemicals in a pulp mill system for the purpose of problem solving or process enhancement is often demonstrated and supported by data produced in laboratory testing. Hercules Chemical Solutions Pte Ltd., a major specialty chemical supplier to the Asian pulp and paper industry, partnered with the Asian Institute of Technology (AIT) on several occasions to provide insight into the efficacy of proposed chemical treatments designed for local operating conditions and wood species. This paper presents an example of a chemically-assisted deresination project. The resulting surfactant chemistry proved to be a superior deresinator for plantation grown acacia wood and has been successfully implemented in an Asian pulp and paper mill.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.5
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• pp.368-376
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• 2005

Coolant rubber hoses for automobile radiators can be degraded and thus failed due to the influence of contacting stresses of air and coolant liquid under thermal and mechanical loadings. In this study, for EPDM(ethylene-propylene diene monomer) rubber conventionally used as a radiator hose material the aging behaviors of the skin part due to thermo-oxidative and electro-chemical stresses were nondestructively evaluated. Through the thermo-oxidative aging test, it was shown that the surface hardness IRHD(International Rubber Hardness Degrees) of the rubber increased with a considerable reduction of failure strain. On account of the penetration of coolant liquid into the skin part the weight of rubber specimens degraded by electro-chemical degradation(ECD) test increased, whereas their. failure strain and IRHD hardness decreased largely. The penetration of coolant liquid seemed to induce some changes in inner structure and micro hardness distribution of the rubbers. Consequently, EPDM rubbers degraded by thermo-oxidative aging and ECD could be characterized nondestructively by micro-hardness and chemical structure analysis methods.

• Carbon letters
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• v.12 no.4
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• pp.223-228
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• 2011

In this present work, the effect of additional heat-treatment (AHT) in the range from $1800^{\circ}C$ to $2400^{\circ}C$ on the chemical composition, morphology, microstructure, tensile properties, electrical resistivity, and thermal stability of commercial polyacrylonitrile (PAN)-based carbon fibers was explored by means of elemental analysis, electron microscopy, X-ray diffraction analysis, single fiber tensile testing, two-probe electrical resistivity testing, and thermogravimetric analysis (TGA). The characterization results were in agreement with each other. The results clearly demonstrated that AHTs up to $2400^{\circ}C$ played a significant role in further contributing not only to the enhancement of carbon content, fiber morphology, and tensile modulus, but also to the reduction of fiber diameter, inter-graphene layer distance, and electrical resistivity of "as-received" carbon fibers without AHT. The present study suggests that key properties of commercial PAN-based carbon fibers of an intermediate grade can be further improved by proprietarily adding heat-treatment without applying tension in a batch process.

• The Journal of Korean Medicine
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• v.30 no.6
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• pp.27-34
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• 2009

Objectives: To evaluate the acute toxic effects and approximate lethal dose of Cheonggan extracts (CGX) in SD rats and beagle dogs. Methods: Male and female rats were divided into 4 groups (Control, CGX 1250, CGX 2500, CGX 5000) respectively and male and female dogs were divided into two groups respectively (Control, CGX 5000) respectively. A single oral dose of CGX was treated to the rats and dogs. Mortality, signs of gross toxicity, and behavioral changes were observed over 14 days. All animals were observed every hour for 4 hours after administration and once a day thereafter for 14 days. Body weights were determined at $0_{th}$, $7_{th}$, and $14_{th}$ days. All surviving animals were sacrificed and necrotized. Major organs were inspected visually for gross findings. Results: No animals died in any of the groups during the experimental period (2 weeks), rats or dogs. Body weights of rats and dogs during the experiment continuously increased in all groups but there was no significant change. No abnormal clinical signs were observed for 2 weeks after a single administration of CGX in any dose group of CGX, rats or dogs. No abnormal findings in major organs were observed in any group of rats or dogs. Conclusion: CGX does not have acute toxic effects in rats or dogs. Therefore, an approximate lethal dose is assumed to exceed 5000 mg/kg in both rats and dogs.

• Journal of Environmental Health Sciences
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• v.50 no.2
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• pp.138-145
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• 2024

Background: Appropriateness issues have emerged regarding the non-application of hazardous substance safety standards for items classified as 'other textile products'. Objectives: Testing for formaldehyde (HCHO) and risk assessment were conducted on 'other textiles products' to provide reference data for promoting product safety policies. Methods: Testing was conducted on five items (102 products) classified as 'other textile products' according to relevant standards (textile products safety standards), and the risk of each product was assessed using the evaluation methodologies of the European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) and European Chemical Agency (ECHA). Results: Out of the 102 products tested, HCHO was detected above the quantification limit in five. Based on these results, the screening risk assessment indicated that three products exceeded the criteria. Upon reassessing the emission and transfer rates of products exceeding the criteria, it was confirmed that there were no instances of exceeding the criteria. Conclusions: Risk assessment results can be used as supporting data for non-application of hazardous substance standards. However, it is deemed necessary to transition towards a management approach based on risks in order to addressing emerging trends such as convergence/new products.

• Journal of the Korean Society for Nondestructive Testing
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• v.17 no.2
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• pp.108-113
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• 1997

Ultrasonic testing is one of the most widely used method of nondestructive testing for pre-service inspection(PSI) & in-service inspection(ISI) in structures of bridges, power plants, chemical plants & heavy industrial fields. It is very important to estimate safety, life, quality of structures. Also, a lot of research for quantities evaluation & analyses inspection data is proceeding. But traditional portable ultrasonic flaw detector had been following disadvantages. 1) Analog ultrasonic flaw detector decreased credibility of ultrasonic test, because it is impossible for saving data & digital signal processing. 2) Stand-alone digital ultrasonic flaw detector cannot effectively evaluate received signals because of lack of its storage memory. To overcome this shortcoming, we develop the computer based ultrasonic flaw detector for nondestructive testing. It can store the received signal and effectively evaluate the signal, and then enhance the reliability of the testing results.

• Journal of the Korean Chemical Society
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• v.50 no.5
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• pp.385-393
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• 2006

In this study, we analyzed the effects of science inquiry learning that applies open-ended hypothesis-testing learning model in a high school chemistry class of grade 11 in respect of science process skills, science-related attitude, and appreciation towards science class by cognitive level. Open-ended science inquiry learning activities on Metals and their applications unit in Chemistry I were developed and applied to the treatment groups while the conventional science activities were applied to the control groups. Four classes of 92 students in a high school located in Seoul were assigned into the treatment and control groups, respectively. According to the results in the test of science process skills, the students treated with the alternative experiments emphasizing open-ended hypothesis-testing obtained higher scores in experimental design, data conversion and description, and hypothesis test than those with conventional experiments but not in problem cognition and definition and hypothesis fixing'. There was negative effect on science-related attitude due to increased roles and tasks in the open-ended science inquiry learning activities.

• Analytical Science and Technology
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• v.25 no.2
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• pp.102-113
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• 2012

Our study researched on unification of KS I ISO standard harmonized with ISO and Official Test Method enacted by Korean Ministry of Environment-drinking water and indoor air quality. We reviewed KS methods related to drinking water and indoor air quality for about 23,000 KS methods. KS methods related environmental field are classified as KS I, total 635 methods and 583 KS I methods were harmonized with ISO. For Environmental Standard methods for drinking water, 100 methods were reviewed according to 232 KS methods related to ISO/ TC 147 "Water Quality". Environmental Standard methods for indoor air quality were reviewed according to 95 KS standard methods related to ISO/TC 146 "Air Quality". By reviews and comparison tests for unifiable ES for drinking water and indoor air quality with KS methods harmonized with ISO, it was evaluated that for 100 ES methods for drinking water, 23 ES methods were unification complete, 29 ES methods were unification possible, 12 ES methods were unification impossible, no corresponding methods were found in KS I ISO for 36 ES methods and for 17 ES methods for indoor air quality,1 ES methods were unification complete, 3 ES methods were unification possible, 3 ES methods were impossible, no corresponding methods were found in KS I ISO for 10 ES methods.

• Journal of the Korean Ceramic Society
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• v.45 no.12
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• pp.788-795
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• 2008

An electrolyte supported SOFC cell was tested at $800^{\circ}C$ in air for 3600 h with an applied current density of $200\;mA/cm^2$ to examine possible cathode degradation issues. A scandium- stabilized zirconia (ScSZ) with additional manganese doping (ScSZ: Mn) was used as electrolyte. A strontium and copper-doped lanthanum ferrite (LaSrCuFe) and platinum were used as cathode and quasi-anode material, respectively. The DC resistance was logged over the complete testing period. Additionally, impedance spectroscopy was used from time to time to track changes of the cell in-situ. Post-test analysis of the cell using methods like scanning electron microscopy imaging and other electrochemical testing methods allow the identification of different degradation sources. The results indicate a promising combination of electrolyte and cathode material in terms of chemical compatibility and electrical performance.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.118-123
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• 2008

A new method for antimicrobial susceptibility testing of vitro-cultured bacteria on an ordinary fluorescence spectrometer was developed. The viable bacteria reduced 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) to produce insoluble particles that displayed intense resonance scattering light. The assay showed a linear relationship between the number of viable bacteria and the intensity of resonance scattering light. Dead bacteria were unable to reduce MTT. Methicillin-resistant Staphylococcus aureus exposed to flavonoids from Marchantia convoluta showed a flavonoids concentration-dependent inhibition of the ability to reduce MTT. In the assay, less than 12 h was required to attain susceptibility results and fewer bacteria were utilized than in traditional methods. The RLS technique could, in combination with the MTT assay, be a rapid and sensitive measuring method to determine the in vitro activity of new antimicrobials.