• Analytical Science and Technology
• /
• v.20 no.6
• /
• pp.502-507
• /
• 2007

X-ray diffraction method has been widely used for qualitative and quantitative analysis of a mixture of materials since every crystalline material gives a unique X-ray diffraction pattern independently of others, with the intensity of each pattern proportional to that material's concentration in a mixture. For determination of mixing ratios, extracting source spectra correctly is important and crucial. Based on the source spectra extracted, a regression model with non-negativity constraint is applied for determining mixing ratios. In some mixtures, however, X-ray diffraction spectrum has sharp and narrow peaks, which may result in partial negative source spectrum from independent component analysis. We propose several procedures of extracting non-negative source spectra and determining mixing ratios. The proposed method is validated with experimental data on powder mixtures.

• International Journal of Highway Engineering
• /
• v.7 no.4 s.26
• /
• pp.1-8
• /
• 2005

Permanent Deformation is one of the most important load-related pavement distresses in asphalt pavements. The Korean Pavement Design Guide currently being developed adopted the mechanistic-empirical approach and needed the pavement distress prediction models. This study intends to develop the model for prediction of permanent deformation in the asphalt layer and estimate the pavement performance. The objectives of this paper are to figure out the factors affecting the permanent deformation and then develop the permanent deformation prediction model for asphalt mixtures. The repeated triaxial load test was Performed on the 19mm dense graded asphalt mixture with variation of temperature and air void. Results from the laboratory tests showed that temperature and air void in asphalt mixtures have significantly influenced on the factors in prediction model. The permanent deformation prediction model for 19m dense grade asphalt mixtures has been developed using the multiple regression approach and validated the proposed permanent deformation prediction model.

• Clean Technology
• /
• v.16 no.1
• /
• pp.26-32
• /
• 2010

The low temperature pyrolysis of polypropylene (PP), polystyrene (PS) and polypropylene-polystyrene (PP-PS) mixture in a batch reactor at the atmospheric pressure and $450^{\circ}C$ was conducted to investigate the synergy effect of PP-PS mixture on the yield of pyrolytic oil. The pyrolysis time was varied from 20 to 80 mins. The products formed during pyrolysis were classified into gas, gasoline, kerosene, gas oil and heavy oil according to the petroleum product quality standard of Ministry of Knowledge Economy. The analysis of the product oils by GC/MS(Gas chromatography/Mass spectrometry) showed that new components were not detected by mixing of PP and PS. There was no synergy effect according to the mixing of PP and PS. Conversions and yields of PP-PS mixtures were linearly dependent on the mixing ratio of samples except for heavy oil yields. Heavy oil yields showed almost constant regardless of the mixing ratio.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.9 no.4
• /
• pp.633-641
• /
• 2021

The study performed long-term performacne evaluation on the hot mix asphalt using the steel slag aggregates and Reclaimed Asphalt Pavement (RAP). The laboratory comparative evaluation was conducted between conventional Hot Mix Asphalt (HMA) which is entitled WC-2 and HMA containing steel slag and RAP which is entitled ES WC-2(R). Dynamic stability test, dynamic modulus test, and fatigue crack test were conducted during the comparative evaluation process. The dynamic stability test result showed that ES WC-2(R) was 140% higher than WC-2. It is noted that ES WC-2(R) showed no inflection point whereas WC-2 showed inflection point during the dynamic stability test which implies ES WC-2(R) has the higher moisture susceptability than WC-2. The dynamic modulus of ES WC-2(R) were 342.3%, 486.7%, and 350.0% higher than WC-2 at medium temperature of 21℃, low temperature of -10℃, and high temperature of 38℃ respectively. The test result showed that rutting resistance of ES WC-2(R) is higher than WC-2 at all temperature spectrum. The fatigue resistance of ES WC-2(R) were 31.7%, 325.3%, 899.9% higher at low stress level, medium stress level, and high stress level, respectively. The test result showed that ES WC-2(R) is higher than WC-2 at all stress levels. Based on the laboratory comparative evaluation, The in-situ scale Accelerated Pavement Test (APT) was conducted comparing WC-2 and WC-2(R). APT found that the rutting resistance of WC-2(R) was 45% higher than WC-2.

• Solar Energy
• /
• v.19 no.2
• /
• pp.57-65
• /
• 1999

In this study $H_2O$-NaCl mixture was selected as a cold thermal storage material and its phase change temperature($liquid{\Leftrightarrow}solid$) was controlled with the molar concentration of NaCl. Ion dipole interaction mechanism and the fusion and crystallization structure of $H_2O$-NaCl were visualized with the low and high concentration of NaCl in the heating and cooling processes. In this study, the original cause of the appearance of two steps phase change period in heating and cooing processes were found by the visualization of the ion dipole interaction mechanism of $H_2O$-NaCl, and the theoretical equation of the phase change temperature variation in the NaCl high molar concentration was rearranged.

• International Journal of Highway Engineering
• /
• v.11 no.1
• /
• pp.127-134
• /
• 2009

This study was performed to establish the process mean which is statistically satisfying the critical limit of deformation strength $(S_D)$, which is found to reflect rutting characteristics of asphalt mixture relatively well. The process means were determined using the critical $S_D$ values (3MPa for local highway and 4MPa for arterial highways), which were obtained from correlation analysis of APA and $S_D$ test data of actual highway projects, and coefficient of variation of 32 combinations of domestic mixtures. The process means of 3.2 MPa for local highway and 4.25 MPa for arterial highways were suggested when using 3 specimens (diameter of 100mm). However, since these values are based on the loading speed of 30mm/min, the higher values, 3.5 MPa for local highway and 4.5 MPa for arterial highways, were suggested, respectively, if the loading speed of 50mm/min is applied using the old Marshall machine, which should give higher test values.

• Journal of the Korean Applied Science and Technology
• /
• v.36 no.2
• /
• pp.635-644
• /
• 2019

The aim of this study was to investigate whitening effect of combination between arbutine and oil soluble licorice extract. Inhibitory effects of arbutin and oil soluble licorice extract against tyrosinase activity and melanogenesis in B16 melanoma cells were assessed in vitro to determine whitening effect. MTT assay with B16 melanoma cells showed that mixture (arbutin and oil soluble) was not each concentration. Both oil soluble licorice extract and arbutin induced dose-dependent inhibition of mushroom tyrosinase activity. Various concentrations (oil soluble extract : arbutin = 1:1. 1:1.5, 1:2, 1:2.5, 1:5) of mixtures also significantly inhibited tyrosinase activity in B16 melanoma cells by 40-51%. In addition, the mixtures reduced the melanin contents of B16 melanoma cells by more than 50% at each concentration. These results suggest that mixtures of arbutin and oil soluble licorice extract are very effective whitening ingredients.

• Journal of the Korean Applied Science and Technology
• /
• v.41 no.2
• /
• pp.318-328
• /
• 2024

In this study, we enhanced the emulsifying power and solubilization of sucrose stearate (SS) by creating mixtures with sodium deoxycholate (SDOC) and PEG-40 hydrogenated castor oil (HCO). We employed the design of mixture experiments (DOME) methodology to identify the optimal composition of the mixture, and the impact of varying the mixture composition on its characteristics was examined through regression analysis of the experimental data. It was revealed that the emulsifying power for coconut oil was most improved when only SDOC was added to SS, and solubilization was most improved when only HCO was added, while the emulsifying power for cetyl ethylhexanoate (CEH) was most significantly improved when SDOC and HCO were added together. As a result of simultaneous optimization of three characteristics, emulsifying power for each of coconut oil and CEH, and solubilization, the optimal surfactant mixture composition was determined as SS 0.7939, SDOC 0.0586, and HCO 0.1475.

• International Journal of Highway Engineering
• /
• v.9 no.4
• /
• pp.193-204
• /
• 2007

Deformation strength($S_D$) is a property which shows relatively good correlation with rut resistance of asphalt mixtures at high temperature. The Asphalt Pavement Analyzer (APA) is widely used as an equipment for estimating rut resistance of asphalt mixtures. The APA was used as corresponding property of the $S_D$ to estimate rutting resistance of asphalt mixtures. Many data were collected to establish the correlation of $S_D$ with APA. For $S_D$ test, the specimen is submerged into the $60^{\circ}C$ water for 30 minutes before applying a vertical load at the speed of 50mm/min to obtain peak load (P) and deformation (y) for $S_D$ calculation. For the same materials, APA test was performed. Relation of the $S_D$ with APA rut depth was evaluated using regression analysis. The $R^2$ value was 0.76, indicating this simple test procedure being a possible method for predicting deformation resistance of asphalt concretes at high temperature. It was also shown that, using the regression model, minimum value(s) of $S_D$ of surface course asphalt mixture or binder course for a particular road level can be determined. The limit values may be possible to use as cut-off value(s) of asphalt mixtures for the layer after further elaborated studies.

• Journal of the Society of Disaster Information
• /
• v.16 no.3
• /
• pp.602-610
• /
• 2020

Purpose: This paper aims to develop an asphalt pavement system with reduced cracks, structural stability and waterproofing at sub-zero temperature conditions. Method: Under various temperature conditions, SIS polymer asphalt, normal asphalt, and guss asphalt were tested for adhesion strength of the binder and deformation strength of the mixture. Result: The adhesion strength of asphalt binder was higher in SIS polymer asphalt than that of normal asphalt and guss asphalt. The deformation strength of the asphalt mixture was almost the same as that of SIS polymer asphalt and normal asphalt. The energy absorption of the SIS polymer asphalt mixture was relatively higher than that of the normal asphalt mixture and the guss asphalt mixture. Conclusion: The maximum load of the SIS polymer asphalt mixture was lower than that of the guss asphalt mixture. However, in sub-zero temperature conditions, sufficient energy absorption was secured by stable load reduction. Therefore, it is expected to improve the durability of asphalt pavement by reducing the occurrence of microcracks with stable fracture behavior.