• Proceedings of the Korean Institute of Building Construction Conference
• /
• 한국건축시공학회 2023년도 봄 학술논문 발표대회
• /
• pp.317-318
• /
• 2023

This study is part of the carbonation degree DB accumulation through quantitative analysis of carbonation depth, Ca(OH)₂ and CO₂ according to the type of finish and years of use of old concrete structures in order to predict the amount of CO₂ that can be absorbed through carbonation of concrete. To this end, the depth of carbonation of the concrete core specimen is measured using an indicator, and the dry amount of water combined with CO₂ in the sample is measured using a differential thermal gravimetric analyzer for samples in the carbonation area and non-carbonated area classified by the indicator, and the absorption compared to the weight of the sample. The amount of absorbed CO₂ was calculated. In addition, the degree of carbonation was calculated through quantitative comparison of Ca(OH)₂ in the carbonation section and non-carbonation section. In the future, we will continue to add the survey and analysis data of dismantled structures and use them as basic data for estimating the amount of carbon dioxide that can be absorbed according to the exposure conditions and years of use by concrete mix.

• The Korean Journal of Applied Statistics
• /
• 제37권3호
• /
• pp.297-309
• /
• 2024

This paper evaluates the performance of the neural network autoregressive model combined with an exponential smoothing model, called the NNARX+ETS model. The combined model utilizes the components of ETS as exogenous variables for NNARX, to forecast time series data using artificial neural networks. The main idea is to enhance the performance of NNAR using only lags of the original time series data, by combining traditional time series analysis methods with the neural networks through NNARX. We employ two real data for performance evaluation and compare the NNARX+ETS with NNAR and traditional time series analysis methods such as ETS and ARIMA (autoregressive integrated moving average) models.

• Journal of Sericultural and Entomological Science
• /
• 제44권2호
• /
• pp.82-86
• /
• 2002

Silk sericin powder was prepared by mechanical treatment from culled-cocoon extract of Bombyx mori silkworm. The physical and structural characteristics of sericin powder were investigated by instrumental analysis. The solubility of sericin powder was decreased nearly half of sericin lyophilized. Amino acid analysis showed that arginine content was decreased from 3.72% to 0.03∼0.07%. XRD showed that molecules of sericin were somewhat regularly arranged by mechanical treatment. On the other hand, FT-IR showed the molecular vibration of silk sericin was not induced by mechanical treatment. Thermal properties also did not changed.

• Journal of Sericultural and Entomological Science
• /
• 제48권1호
• /
• pp.11-15
• /
• 2006

Antheraea yamamai silk fibroin powder was prepared by treatment with HCl. The prepared A. yamamai fibroin hydrolysate was characterized by gel filtration chromatography, amino acid analysis, X-ray diffractometry, circular dichroism analysis, differential thermal analysis, and thermogravimetry. The average molecular weight of A. yamamai powder was about 430 and the major amino acids composed of the powder were Ala and Ser. According to XRD analysis, A. yamamai silk powder showed sharp diffraction peaks at $2{\theta}=20.34^{\circ}\;and\;31.5^{\circ}$. CD spectrum showed a peak around 220 nm and a should 215 nm, assigned to ${\alpha}-helix\;and\;{\beta}-sheet$ structure, respectively. DSC and TGA showed that the maximum degradation temperature of powder was around $250{\sim}270^{\circ}C$. Moreover, no harmful heavy metal was contained in the A. yamamai silk fibroin hydrolysate.

• Journal of the Korean Society of Propulsion Engineers
• /
• 제19권5호
• /
• pp.15-21
• /
• 2015

The thermal decomposition characteristics of the ZPP(Zirconium/Potassium perchlorate), widely used as a primary charge of initiators, were investigated by differential scanning calorimetry(DSC). The DSC results with different heating rates were elaborated with AKTS-Thermokinetics software for the determination of the kinetic parameters of the thermal decomposition of ZPP. There was good agreement between the experimental and the simulation curves, based on the determined kinetic parameters, which indicates the validity of the kinetic description of the thermal decomposition process of ZPP.

• Journal of Sericultural and Entomological Science
• /
• 제39권1호
• /
• pp.73-78
• /
• 1997

The crystalline fraction of silk fibroin (Fcp) was obtained from the aqueous solution of silk fibroin hydrolyzed by $\alpha$-chymotrypsin. The molecular weight of Fcp was found approximately 7000 by using high speed GPC. On the other hand, a high molecular weight of PIFcp product could be obtained by the reverse reaction of enzymatic proteolysis of Fcp precipitates. Some parts of this PIFcp have the molecular weights of approximately 17000 and 24000. As a result of x-ray diffraction analysis, the crystal structure of Fcp and PIFcp was turned out silk-II type and silk-I type, respectively. Upon the reverse reaction of enzymatic protelysis, the structural transition occured from silk-II type to silk-I type crystal for the most of Fcp precipitates. It was confirmed that PIFcp might be somewhat stable crystal structure of silk-I type according to the thermal analysis as well as x-ray diffraction method.

• Electrical & Electronic Materials
• /
• 제10권3호
• /
• pp.217-225
• /
• 1997

In this study, the PVDF organic thin film was fabricated by the physical vapor deposition method to be dry-process. The distance of heat source and substrate was 5[cm] and the temperature of substrate was 30[.deg. C], when the pressure had reached 2.0 x 10$^{-5}$ [Torr], the temperature of heat source was reached to 285[.deg. C] to heat at 6-8[.deg. C/min] rate, the shutter was opened and deposition was started. TG-DTA(Thermogravimetric-Differential Thermal Analysis) spectrum of PVDF pellets showed that endothermic peak arose at 170[.deg. C] and exothermic peak at 524[.deg. C], but that of thin PVDF film showed that endothermic peak arose at 145[.deg. C] and exothermic peak at 443[.deg C]. The current density was increased linearly with increasing voltage but increased nonlinearly with higher electric field than 250[kV/cm] and activation energy was about 0.667[eV] at the temperature of 30-90[.deg. C].

• Economic and Environmental Geology
• /
• 제16권3호
• /
• pp.149-161
• /
• 1983

Fuller's earth deposits from Miocene sedimentary sequences in Gyeong Sang-do contain up to 95% Ca-montmorillonite accompanied by cristobalite, clinoptilolite, mordenite, quartz, feldspar and X-ray amorphous material. Differential thermal analysis, infrared and electron microscopic data are given for the montmorillonite component. The ease with which the exchangeable calcium of the montmorillonite could be replaced by sodium (to give a product with properties similar to that of a bentonite) was monitored by the Atterberg liquid limit test. Some samples tested as possible binders for foundry moulding sands gave results that compared favourably with material currently being used for this application. Many of the samples also met the OCMA specifications for clays used in drilling muds.

• Economic and Environmental Geology
• /
• 제15권4호
• /
• pp.205-219
• /
• 1982

The Eosangcheon manganese ore deposits occur as supergene weathering deposits along quartz porphyry dikes developed in the Ordovician Heungweolri dolomite and Samtaesan limestone formations. The manganese ores are composed of manganese oxide minerals and associated other minerals. Rancieite and todorokite are abundantly found, and birnessite, nsutite, pyrolusite and chalcophanite are found in minor quantities. Associated other minerals are calcite, gypsum, goethite, lepidocrosite, quartz, and sericite. Microscopic, chemical, X-ray powder diffraction, infrared absorption spectroscopic and differential thermal analyses have been made for manganese oxide minerals and associated other minerals. The relationship of birnessite and rancieite was studied by means of X-ray powder diffraction and infrared absorption spectroscopic analyses. It is assumed that these minerals are closely related to each other in crystal structure, but separate species. The manganese oxide minerals were formed mainly by replacement, precipitation from solution, and recrystallization in the supergene weathering environment. The trend of formation of manganese oxide minerals is: (Rhodochrosite)-(todorokite)-(birnessite, rancieite)-(nsutite, pyrolusite, chalcophanite).

• Polymer(Korea)
• /
• 제26권6호
• /
• pp.737-744
• /
• 2002

Thermodynamic miscibility of the binary blends composed of semi-crystalline poly (butylene 2,6-naphthalate) (PBN) and amorphous poly (4-vinylphenol) (PVPh) was investigated using differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. DSC scan results showed that there was a single glass transition temperature (T$\_$g/) for each blend. Crystalline melting temperature (T$\_$m/) depression of the PBN in the blends was also observed with the increase of PVPh content. Both results of the single T$\_$g/ and the depression of T$\_$m/ for the PBN/PVPh blends indicate that the blends are thermodynamically miscible at the molecular level. FTIR spectroscopic analysis confirmed that strong intermolecular hydrogen bonding interactions between the ester carbonyl groups of the PBN and the hydroxyl groups of the PVPh are occurred.