• Journal of Pharmaceutical Investigation
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• v.39 no.2
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• pp.107-110
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• 2009

To investigate the interaction and skin damage of valsartan with polysorbate 80, the physical mixture of valsartan and polysorbate 80 was prepared and then its adhesion, dispersibility, DSC and skin damage in nude rats were investigated. The physical mixture of valsartan and polysorbate 80 appeared as an aggregated form and could hardly be dispersed in water. The DSC curve showed that physical mixture disappeared the intrinsic peaks of valsartan and polysorbate 80 at about $115^{\circ}C$ and $170^{\circ}C$, respectively. It appeared a new relatively broad endothermic peak at about $150^{\circ}C$, suggesting that valsartan was chemically interacted with polysorbate 80. Furthermore, it induced the severe skin irritation and damage in nude mice. Thus, polysorbate 80 must not be used in the preparation of valsartan-loaded pharmaceutical dosage forms.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.5
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• pp.125-132
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• 2000

This study was performed to evaluate the physical properties of reinforced soil mixture powder. Soil sample was prepared by passing into the standard sieve of No. 200 and reinforcement materials were calcium carbonate, quicklime and portland cement. Fineness, setting time, and compressive strength test for reinforced soil mixture powder were performed and analyzed to investigate their physical properties. The main results were summarized as follow. The compressive strength of soil mixture powder itself and most reinforced was reinforced according to increasing in the mixture rate of reinforcement and the rate of increase was remarkably higher in the cement reinforced soil moisture powder. It was appeared that the early compressive strength is considering higher in the cement reinforced soil moisture powder with 2% of moisture rate of accelerator.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.5
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• pp.891-900
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• 2001

The purpose of this study were to evaluate the physical properties and dyeability of cellulase and alkali(NaOH, KOH) treated ramie/man-made fiber mixture fabrics. The mixture fabrics were plain weave made by rayon and polyester fiber as warp yarn, and ramie as weft yarn. The crease resistance, drape, tensile strength, and water absorbancy were measured for test fabrics. The K/S value of dyed fabrics were calculated using color difference meter. Also colorfastness to washing and sunlight of dyed fabrics were evaluated. The results obtained from this study were as follows: Thickness and weight per unit area of alkali treated two mixture fabrics(rayon/ramie, polyester/ramie) increased compared to those of untreated fabrics, but cellulase treated fabrics did not changed a little. And alkali treated rayon/ramie mixture fabrics showed more change than polyester/ramie mixture fabrics on the thickness and weight. Tensile strength and water absorbancy of cellulase treated fabrics decreased compared to those of untreated, but crease resistance increased. Crease resistance, tensile strength(warp direction), water absorbancy and drape of NaOH treated rayon/ramie mixture fabrics decreased compared to those of untreated, but tensile strength(weft direction) increased. Water absorbancy and drape of NaOH treated polyester/ramie mixture fabrics decreased compared to those of untreated, but crease resistance and tensile strength(weft direction) increased. Tensile strength of KOH treated two mixture fabrics increased compared to that of untreated, but water absorbancy and drape decreased. Total hand of cellulase and alkali treated rayon/ramie mixture fabrics was improved compared to untreated. Dyeability of treated mixture fabrics was increased compared to untreated.

• Geomechanics and Engineering
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• v.35 no.4
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• pp.425-436
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• 2023

An effective tool for researching actual problems in geotechnical and mining engineering is to conduct physical modeling tests using similar materials. A reliable geometric scaled model test requires selecting similar materials and conducting tests to determine physical properties such as the mixing ratio of the mixed materials. In this paper, a method is proposed to determine similar materials that can reproduce target properties using a polynomial model based on experimental results on modeling materials using a gypsum-sand mixture (GSM) to simulate rocks. To that end, a database is prepared using the unconfined compressive strength, elastic modulus, and density of 459 GSM samples as output parameters and the weight ratio of the mixing materials as input parameters. Further, a model that can predict the physical properties of the GSM using this database and a polynomial approach is proposed. The performance of the developed method is evaluated by comparing the predicted and observed values; the results demonstrate that the proposed polynomial model can predict the physical properties of the GSM with high accuracy. Sensitivity analysis results indicated that the gypsum-water ratio significantly affects the prediction of the physical properties of the GSM. The proposed polynomial model is used as a powerful tool to simplify the process of determining similar materials for rocks and conduct highly reliable experiments in a physical modeling test.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.336-340
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• 1999

This study was performed to evaluate the physical properties of reinforced soil-mixture powder. Soil was used to be powder that passed by the No. 200 mech and the reinforcement as calcium carbonate, quicklime and portland cement used for this study to improve soil. We resulted from fineness , setting time, and compressive strength test of reinforced soil-mixture powder. We've got the two conclusions . The first , in case that we were used reinforced soil-mixture powder included some portland cement, the higher the mixture rates of the reinforcement , the wider the difference theoretical data with experimental data. The second, the setting time of reinforced soil-mixture powder is faster than soil powder itself and the reinforcement for promoting strength was proved that calcium carbonate was proper than others if we compared it with other reinforcment.

• International Journal of Highway Engineering
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• v.4 no.4 s.14
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• pp.53-66
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• 2002

Asphalt binder characteristics in asphalt mixture are changed due to aging. However. depending upon aggregate and binder used, asphalt mixture dose not show the same level of stiffness and brittleness under the same ageing level. The factors affecting Physical Properties change of the asphalt binder within aged asphalt concrete are not well known and there is limited study which is dealing with this topic This study dealt with evaluation of physical properties of asphalt binder recovered from the mixtures after short-term and long-term aging. Two asphalts. two aggregates. two gradations and four polymers were used to make 32 mixture combinations. The mixtures were prepared and aged artificially in a forced draft oven. The measured physical properties included absolute viscosity, kinematic viscosity and penetration. Statistical analyses were carried out to find out the factor(s) having a significant effect on change of physical property of asphalt binder due to asphalt mixture aging. The results of study shown that aggregate, gradation and polymer had a significant effect on change of physical properties of asphalt binder.

• Archives of Pharmacal Research
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• v.9 no.1
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• pp.55-61
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• 1986

To increase the dissolution rate of piroxicam, chitin and chitosan which are widely occurring biodegradable natural materials were used as drug carriers. The ground mixtures of piroxicam with chitin or chitosan were prepared by grinding in a ball mill. The dissolution rates of piroxicam from the ground mixtures were enhanced markedly than that from the physical mixtures or from intact piroxicam. The X-ray diffraction peaks disappeared in the ground mixture indicating the production of the amorphous form. The comparison of infrared spectra of the physical mixture and the ground minture showed an interaction such as association between the functional groups of piroxicam and chitin or chitosan in the molecular level. The weight losses in TGA curves shoed all the same patterns. However, in the ground mixture by DTA curve, the undothermic peak due to the fusion of piroxicam was disappeared indicating the different thermal property.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.166-171
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• 1999

Porous concrete contains about 20% voids after compaction so that it has high permeability which secures underground water resources. It is introduced in domestic since 1980' but has problems such as lack of optimized mixture, low strength and durability, efflorescence and other defects, etc. In this study, several mixture were designed based upon site works, and test specimens for compressive strength, tensile strength, flexual strength and permeability, were prepared in a laboratory. After 28days of curing, every performance was tested to find optimum mixture. The mixture was proposed as 380kg/㎥ of unit cement weight, 32% of W/C 10∼13mm of aggregate.

• Journal of Mechanical Science and Technology
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• v.18 no.3
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• pp.513-525
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• 2004

This paper reports an experimental study on flow boiling of pure refrigerants R l34a and R l23 and their mixtures in a uniformly heated horizontal tube. The flow pattern was observed through tubular sight glasses with an internal diameter of 10㎜ located at the inlet and outlet of the test section. Tests were run at a pressure of 0.6 MPa in the heat flux ranges of 5-50㎾/㎡, vapor quality 0-100 percent and mass velocity of 150-600㎏/㎡s. Both in the nucleate boiling-dominant region at low quality and in the two-phase convective evaporation region at higher quality where nucleation is supposed to be fully suppressed, the heat transfer coefficient for the mixture was lower than that for an equivalent pure component with the same physical properties as the mixture. The reduction of the heat transfer coefficient in mixture is explained by such mechanisms as mass transfer resistance and non-linear variation in physical properties etc. In this study, the contribution of convective evaporation, which is obtained for pure refrigerants under the suppression of nucleate boiling, is multiplied by the composition factor by Singal et al. (1984). On the basis of Chen's superposition model, a new correlation is presented for heat transfer coefficients of mixture.

• Journal of Pharmaceutical Investigation
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• v.17 no.4
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• pp.175-181
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• 1987

To increase the dissolution rate of furosemide, chitin and chitosan which are widely occurring biodegradable natural materials were used as drug carriers. The ground mixtures of furosemide with chitin or chitosan were prepared by grinding in a ball mill. The ground mixture showed a faster and more enhanced dissolution rate than the physical mixture or intact furosemide. The crystalline peaks of furosemide disappeared in the ground mixtures indicating the production of amorphous form. The comparison of infrared spectra of the physical mixture and the ground mixture showed an interaction such as association between the functional groups of furosemide and chitin or chitosan in the molecular level. The weight losses in TGA curves showed all the same patterns. However, the endothermic peak due to the fusion of furosemide in DTA curve disappeared in the ground mixture indicating the different thermal property. The dissolution of furosemide from ground mixtures was fast in the order of chitosan and then chitin. The co-grinding technique with chitin or chitosan provided a promising way enhancing the dissolution rate of practically insoluble drug.