• Journal of Environmental Health Sciences
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• v.41 no.6
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• pp.405-411
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• 2015

Objectives: The purpose of this study is to evaluate the optimum conditions for oral mucosal irritation testing using the buccal pouch of hamsters. Methods: Test materials were applied to the buccal pouch of seven-week old male Syrian hamsters (SLC, Japan) four times at one-hour intervals and macroscopic changes were examined at 24 hours after final treatment. After sacrifice, the buccal pouches were removed and prepared for histopathological evaluation. In order to set the exposure time, we performed exposure tests of 5, 12, 18 and 23 minutes using sodium lauryl sulfate (SLS) 1% and set the treatment volume from the test results at 2, 3, or 4 ml treatment using SLS 1%, Triton X-100 1% and ethanol. After setting the experimental conditions, seven groups of materials [sodium lauryl sulfate (SLS) (1%), Triton X-100 (1%), hydrogen peroxide (3%), ethanol (100%), chlorhexidine (0.2%, 2%), phosphate buffer saline (PBS)] were assessed. Results: Experimental conditions of material exposure time were fixed as 18 minutes from the exposure tests of 5, 12, 18 or 23 min using sodium lauryl sulfate (SLS) 1%. Treated volume was set as 4 ml per each pouch from the test results of 2, 3, or 4 ml treatments using SLS 1%, Triton X-100 1% and ethanol. The results in terms of irritation degree were in the order of sodium lauryl sulfate (SLS) (1%) > Triton X-100 (1%) ${\fallingdotseq}$ hydrogen peroxide (3%) > ethanol (100%) ${\fallingdotseq}$ chlorhexidine (0.2%, 2%) > phosphate buffer saline (PBS). Conclusion: From this study, suitable conditions for hamster mucosal irritation testing were suggested and this method was verified through materials commonly used on oral mucosal membranes.

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.849-860
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• 1996

Natural zeolites which were known to occur in sedimentary clinoptilolite, were treated by thermal and chemical methods, and their adsorption characteristics of Cu(II) were studied. Analyses by FT-IR, S. E. M, TGA/DSC, and XRD showed that the adsorption capacity of Cu(II) on the zeolite decreased gradually at the temperatures of above $400^{\circ}C$. The zeolites, which treated with NaOH and NaCl, show higher absorbility in acid solution. The adsorption rate of Cu(II) in the presence of surfactants(LAS, POE AE) on the thermally or chemically treated zeolites varied depending on pH, anion or nonion surfactants.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.2
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• pp.182-188
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• 2001

This paper presents the vibration characteristics of a rectangular plate with $45^{\circ}$ oblique crack subjected to a uniaxial tension. The experiment is adopted by the time-average Electronic Speckle Pattern Interferometry(ESPI) method. The natural frequency and mode shape are considered accurately according to the increase of tensile load. When tensile load is zero, the vibration modes we agreed with the smooth and the $45^{\circ}$ obliquely cracked plate. But according to the increasement of load it is shown that vibration modes are extremely varied. The effects of the crack under the vibration are discussed in detail. It is indicated that the increase of load makes the variation of the frequencies and modes complicate in the range of even a small load. The results are agreed with the FEM analysis within 5%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.108-114
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• 2018

Due to the development of nondestructive testing techniques, methods of inspecting cracks in mechanical parts have drawn attentions. Among various non-destructive testing methods the acoustic resonance method which analyzes the natural frequencies has been developed into a technique suitable for the prompt judgements of the existence of the defects in the mechanical parts. In this study, we investigated the crack inspection technique to examine the cracks in the yoke tubes by using the acoustic resonance method and realized the system to quickly detect the cracks. A 24bit ADC circuit and an MCU were installed for the smooth data collection, and a TCP / IP communication interface was configured for the data communication with PC. We used a microphone as a sensor measuring the vibrations. We constructed an analysis software to obtain the frequency spectra of the vibrations, to find the existence of the cracks, and to feedback to the user. Tests were conducted using the yoke tubes manufactured in the real industrial field. The tests were successfully conducted to distinguish the good products from the defective (cracked) products and confirmed that they can be employed in the actual industrial field.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.2 s.54
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• pp.27-38
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• 2007

A series of forced vibration tests and ambient vibration measurement was conducted on a four-story reinforced concrete building damaged in the 1994 Northridge earthquake. Both low amplitude broadband and moderate amplitude harmonic excitation were applied using a linear shaker and two eccentric mass shakers, respectively, and ambient vibrations were measured before and after each forced vibration test. Accelerations, interstory displacements, and curvature distributions were monitored using accelerometers, LVDTs and concrete strain gauges. Natural frequencies and the associated mode shapes fur the first 7 modes were identified. Fundamental frequencies determined from the eccentric mass shaker tests were 70% to 75% of the values determined using ambient vibration data, and 92% to 93% of the values determined using the linear shaker test data. Larger frequency drops were observed in the NS direction of the building, apparently due to damage that was induced during the Northridge earthquake.

• The KIPS Transactions:PartD
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• v.15D no.4
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• pp.505-512
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• 2008

In order to do requirement-based testing of embedded system, we must have correct requirement specifications. But, natural language requirements of a client have ambiguity, inaccuracy, and inconsistency. To solve these problems, natural language requirements are modeled with modeling language such as UML and Simulink. During a modeling phase, the requirements are rearranged and retranslated in use-case. These activities are disadvantages of modeling. In this paper, we propose the technique, which is how to model a embedded system requirement into a model without rearranging and retranslating. This technique 1) represent a embedded system requirement with graphical language, and 2) model a requirement into a model. Because this technique only describes "what-to-do" of the requirement, this technique is useful to not only the low-level requirements but also the high-level requirements. We show some example systems modeled by REED, which has adopted this technique.

• Journal of the Korean Wood Science and Technology
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• v.48 no.1
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• pp.32-40
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• 2020

While the utilization of wood as a raw material in related industries has been increasing with the population increasing, the availability of wood from natural forests has continued to decline. An alternative to this situation is the manufacture of particleboard from non-wood lignocellulose materials through the modification of sandwich particleboard (SPb) using bamboo strands as reinforcement. In this study, strandsof belangke bamboo (Gigantochloa pruriens W) and tali bamboo (Gigantochloa apus) were utilized. The non-wood particles included sugar palm fibers, cornstalk, and sugarcane bagasse. The board was made in a three-layer composition of the face, back, and core in a ratio of 1: 2: 1. The binder used was 8% isocyanate resin. The sheet was pressed at a temperature of 160℃ for 5 min under a pressure of 3.0 N/㎟. Testing included physical and mechanical properties based on the JIS A 5908 (2003) standard, while acoustic testing was based on ISO 11654 (1997) standards. The results showed that using bamboo strands as reinforcement has an effect on the mechanical and physical properties of SPb. Almost all the types of boards met the JIS A 5908 (2003) standards, with the exception of thickness swelling (TS) and internal bond (IB) parameters. Based on the thickness swelling parameter, the C-type board exhibited the best properties. Overall, the B-type board thatused a belangke bamboo strand for the surface and sugarcane bagasse as the core underwent the best treatment. Based on the acoustical parameter, boards using a tali bamboo strand for the surface and sugar palm fiber as the core (E-type board) exhibited good sound absorption properties.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.28 no.1
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• pp.166-185
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• 2002

Aroma oils extracted from the natural material have antibacterial, antivirus, antiinflammatory, and preservative effect. The preserve efficacy testing between aroma oils and parabens as an artificial preservative had been performed and then it had been suggested that aroma oil was possibile to apply to the cosmetics. Aroma oils were pine, rosemary, lemon and eucalyptus, and parabens were methylparaben, blitylparaben. Antiseptic concentrations of aroma oils and parabens having 0.0, 0.1, 0.2, 0.4, 0.8, 1.0wt% were tested respectively. Escherichia coil(ATCC No.8739), Pseudomonas aeruginosa(ATCC No. 9027) which are gram-negative and Staphylococcus aureus (ATCC No. 6538), Bacillus subtilis(ATCC No. 6633) which are gram-positive were used as the test organisms. Disk paper and broth dilution methods were used as the methods of preservative efficacy testing. The antibacterial activity of aroma oils and parabens for gram-positive were better than that for gram-negative. For the antibacterial activity aroma oils were better than parabens. Among the aroma oils, rosemary and pine having superior antibacterial activity were selected and blended to illuminate if there is any synergy, There was synergical effect and optimum ratio of aroma blend is 3 : 1(rosemary pine) in this study.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.1
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• pp.9-21
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• 2021

In this study, the difference between the preservative efficacy test (PET) used for water dispersion formulations and PCPC (personal care products council) guidelines alternative test method, direct contact membrane method, and surface mold test should be studied to determine what should be considered during preservative efficacy test of water non-dispersible formulations. We conducted improved PETs when using the alternative test method compared with the test methods used for stick and pressed powder. There was no significant improvement between water-in-silicon emulsions and loose powder using alternative test methods. When we checked the results of the presence and absence of the preservative system for each product, we could see that there were differences in testing methods. As a result, improved levels of results could be obtained using both existing and alternative test methods when measuring preservatives for water non-dispersible formulations. In addition, in the case of stick and pressed powder, the results were more effective when the preservative test method applied to the consumer's method of use was applied.

• Journal of Conservation Science
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• v.33 no.2
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• pp.97-106
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• 2017

The purpose of this study was to investigate the characteristics and detergency of natural surfactants for the cleaning of excavated fabrics. For this purpose, SDS, a synthetic surfactant, was selected as the control, and five types of natural surfactants, namely, LES, apple wash, tea saponin, cornacopa, and coco betaine were selected. The structures of the surfactants were confirmed by FT-IR spectroscopy analysis, and the characteristics of the surfactants were determined by measuring the pH and surface tension. In addition, detergency testing was carried out on four artificially soiled fabrics and fragments of excavated fabrics. From the results, apple wash, tea saponin, and cornacopa were found to be as good as SDS in terms of detergency in the cleaning of artificially soiled fabrics, and the detergency of tea saponin and coco betaine was found to be good for cleaning excavated fabrics. Therefore, considering the safety and detergency of detergents, among natural surfactants, tea saponin is found to be most suitable for the cleaning of excavated fabrics.