• Journal of Environmental Health Sciences
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• v.50 no.1
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• pp.43-53
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• 2024

Background: Exposure assessment is an important part of risk assessment for consumer products. Exposure models are used when estimating consumer exposures by considering exposure routes, subjects, and circumstances. These models differ based on their tiers, types, and target populations. Consequently, exposure estimates may vary between models. Objectives: This study aimed to compare the results of different exposure models using identical exposure factors. Methods: Chemical exposure from consumer products was calculated using four consumer exposure assessment models: Targeted Risk Assessment 3.1, Consumer Exposure Model 2.1 (CEM), ConsExpo web 1.1.1, and the Korean Exposure Algorithm (primary and detailed) issued by the Ministry of Environment, No. 972 (MOE). The same exposure factors were used in each model to calculate inhalation and dermal exposures to acetaldehyde, d-limonene, and naphthalene in all-purpose cleaners, leather coating sprays, and sealants. Results: In the results, TRA provided the highest estimate. Generally, MOE (detailed), CEM and ConsExpo showed lower exposures. The inhalation exposure for leather coating spray showed the largest differences between models, with differences reaching up to 1.2×10⁷ times. Since identical inputs were used for the calculations, it is likely that the models significantly influenced the estimated results. Conclusions: Despite using the same exposure factors to calculate dermal and inhalation exposures, the results varied substantially based on the model's exposure algorithm. Therefore, selecting an exposure model for assessing consumer products should be done with careful consideration.

• Journal of the Korean Wood Science and Technology
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• v.27 no.1
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• pp.37-49
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• 1999

The effect of fire-retardant treatment and redrying on the mechanical properties of radiata pine sapwood were evaluated. Small, clear specimens were treated with three different fire-retardant(FR) chemicals, borax-boric acid(BRX), minalith(MIN), and pyresote(PYR), with target retentions of 30 and 60kg/$m^3$, and then redried at maximum dry-bulb temperature of $25^{\circ}C$, $60^{\circ}C$, $80^{\circ}C$ or $110^{\circ}C$. Each specimen, including untreated and water-treated controls, was tested in static bending and in compression parallel to grain. The extent of strength reduction was dependent on the type of FR chemicals, retention, and redrying temperature, and a highly significant interaction existed between FR treatment and redrying temperature. Modulus of rupture(MOR) and work to maximum load(WML) were significantly decreased by FR treatment and redrying. None of three FR chemicals adversely affect modulus of elasticity (MOE) and maximum crushing strength(MCS). MOE of BRX treatment and MCS of both BRX and PYR treatment increased significantly compared to untreated controls. No significant differences existed between retention levels except for MOE and MCS of some combinations of FR chemicals and redrying temperatures. Although MOE and MCS was not significantly affected by any of the redrying temperatures, these properties were generally decreased with the increase in redrying temperature. The significant reduction in MOR and WML was observed in BRX treatment when dried at temperatures of $60^{\circ}C$ and above, and in MIN and PYR treatment when dried at temperatures of $80^{\circ}C$ and above. Consequently, BRX-treated radiata pine should not be redried at temperatures >$60^{\circ}C$, and MIN- and PYR-treated radiata pine should not be redried at temperatures > $80^{\circ}C$ where bending strength and energy-related properties are important design considerations.

• Journal of the Korean Wood Science and Technology
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• v.49 no.4
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• pp.336-359
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• 2021

In this study, hybrid CLT research and development trends were analyzed to improve the low rolling shear strength of CLT, a large wooden panel used in high-rise wooden buildings. Through this, basic data that can be used in research and development directions for localization of CLT were prepared. As a way to improve the low rolling shear strength, the use of hardwood lamina, the change of the lamina arrangement angle, and the use of structural composite materials are mainly used. Rolling shear strength and shear modulus of hardwood lamina are more than twice as high as softwood lamina. It confirmed that hardwoods can be used and unused species can be used. Rolling shear strength 1.5 times, shear modulus 8.3 times, bending stiffness 4.1 times improved according to the change of the layer arrangement angle, and the CLT strength was confirmed by reducing the layer arrangement angle. Structural wood-based materials have been improved by up to 1.35 times MOR, 1.5 times MOE, and 1.59 times rolling shear strength when used as laminas. Block shear strength between the layer materials was also secured by 7.0 N/mm², which is the standard for block shear strength. Through the results of previous studies, it was confirmed that the strength performance was improved when a structural wood based materials having a flexural performance of MOE 7.0 GPa and MOR 40.0 MPa or more was used. This was determined based on the strength of layered materials in structural wood-based materials. The optimal method for improving rolling shear strength is judged to be the most advantageous application of structural wood based materials with strength values according to existing specifications. However, additional research is needed on the orientation of CLT lamina arrangement according to the fiber arrangement of structural wood-based materials, and the block shear strength between lamina materials.

• Aerospace Engineering and Technology
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• v.4 no.2
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• pp.42-49
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• 2005

Technical performance measurement (TPM) has been in widespread use for many years and is recognized as a highly useful method that can identify deficiencies in meeting aircraft system requirements, provide early warning of program problems, and be used to monitor technical risks. This paper presents the overview of technical performance measurement method and its application in aircraft system development for KHP, KTX etc.

• Journal of the Korea Furniture Society
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• v.23 no.1
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• pp.68-74
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• 2012

In this study domestic thinning and small diameter woods of Giant dogwood (Cornus controversa Hemsl) was used. To increase the utilizability of wood, the utilizability was proposed after manufacturing laminated wood by pressing and heating. The physical and mechanical characteristics of Laminated wood were investigated and the color change was measured, using a Chromaticity coordinates, after being pressed at 10% (45 mm), 20% (40 mm), 30% (35 mm) for 5 minutes, using Stopper, and then heated at $180^{\circ}C$ for 6, 12, 24 and 48 hours. The results were as follows. Wood density, compressive strength, MOR, MOE are increased with increasing pressing rate but decreased as heating time is increased after pressing. However, Color change is clear, dimensional stability is improved after pressing and heating.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.1
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• pp.93-100
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• 1993

This study was carried out to investigate the relationship between the traffic signal systmes and the air pollutants emitted by the motor vehicles at Kangnam Intersection. One of the most important measures of effectiveness (MOE) in traffic studies is the delay to vehicles in the system. Delay represents indirect costs to the motorist in terms of time loss and a direct cost in terms of fuel consumption during idling. The results of TRANSYT-7F modeling was correlated among delay, fuel consumption and total travel tiem. Air pollutants emission rate can be calculated by the results of modeling and the Korean type emission factor. As expected the highest emissions, for air pollutants, are observed during the morning rush hours (07 : 00-10 : 00). For better results of modeling, the TRANSYT-7F model needs to modify for the Korean type of traffic model. The results of this study indicate that the variation of air pollutants emission rates were closely related to the traffic signal system.

• Journal of the Korea Furniture Society
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• v.10 no.1
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• pp.57-63
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• 1999

This study was carried out to analyze the relationship between basic physical properties and acoustical characteristics of imported violin wood and to offer the information on raw material procurement and incoming-material quality control to domestic violin makers which have purchased most raw materials from European exporting countries at high expense. Equilibrium moisture content of European spruce with lower specific gravity after the prolonged storage was rather higher than that of European maple with higher specific gravity. The specific gravity of spruce increased with decreasing annual ring width, however, that of narrower annual ring. Increasement in specific gravity enhanced the dynamic Young's modulus of both wood species, but influenced the vibration energy loss by internal friction differently between two species. For dynamic MOE, qurater-sawn spruce was higher than the flat-sawn, but maple showed the reverse directional characteristics. Consequently, it would be well for violin makers to establish the standard for materials and quality control system to assure the quality of their violin products.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.22-27
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• 2006

This paper describes the development of the stream-tube based dispersion model for modeling contaminant transport in open channels. The operator-splitting technique is employed to separate the 2D contaminant transport equation into the pure advection and pure dispersion equations. Then the total variation diminishing (TVD) schemes are combined with the second-order Lax-Wendroff and third-order QUICKEST explicit finite difference schemes respectively to solve the pure advection equation in order to prevent the occurrence of numerical oscillations. Due to various limiters owning different features, the numerical tests for 1D pure advection and 2D dispersion are conducted to evaluate the performance of different TVD schemes firstly, then the TVD schemes are applied to experimental data for simulating the 2D mixing in a straight trapezoidal channel to test the model capability. Both the numerical tests and model application show that the TVD schemes are very competent for solving the advection-dominated transport problems.

• 한국약용작물학회:학술대회논문집
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• 2011.04a
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• pp.422-423
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• 2011

• Mycobiology
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• v.48 no.3
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• pp.233-239
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• 2020

A small-spored Alternaria was found from black spots of storaged Koerle pear (Pyrus sinkiangensis), one of the economically important fruit in Xinjiang province, China. The morphology is similar to A. limoniasperae but obviously different in secondary conidiophores and conidial septa. A phylogenetic analysis using sequence datasets of ITS, GAPDH, TEF1, RPB2, Alt a1, OPA10-2, and EndoPG genes revealed that it belonged to the Alternaria alternata complex group. Pathogenicity tests illustrated that the fungus was the causal pathogen of black spot on Koerle pear fruit.