• Journal of Sericultural and Entomological Science
• /
• v.31 no.2
• /
• pp.121-126
• /
• 1989

Two kinds of solution for the measurement of solubilities of Sericin are prepared as followings at temperature 90 deg. C. One has the total carbonate concentration as 0, 50, 100mg CO2/l prepared with non-carbonate distilled water, sodium hydrogen carbonate and 0.1N HCI and NaOH, the other has total hardness, that is, calcium hardness or magnesium hardness as 0, 20, 50, 100mg CaCO2/l respectively prepared with non-carbonate distilled water, calcium carbonate and magnesium oxide. Solubilities of Cocoon layer Sericin at above solution gives following results ; 1. pH shows little effect on the solubility of Sericin at the non-carbonate solution but at the carbonate solution pH shows a sensitive effect on the solubility of Sericin. These means that pH controls the concentration of H2CO3, HCO3-and CO32- which prevent and promote the solution of Sericin. 2. After the cocoon layer treatment at the solution, the initial pH of 4.0, 7.0, 9.0 of the solution changed to 6.0-6.5 at the lower total carbonate solution. However in the higher total carbonate solution pH did not changed very much. This may be explained by the buffer action of carbonate. 3. The effect of the hardness on the solubility of Sericin was not found in the non-carbonate solution with the standard hardness after treatment of cocoon layer.

• Journal of Powder Materials
• /
• v.16 no.3
• /
• pp.167-172
• /
• 2009

This study has been carried out to investigate the non-isothermal behaviors and kinetic parameter of calcium carbonate by different thermal analysis methods. At the heating rate of $10^{\circ}C$/min, the onset calcination temperature, the peak and final temperatures of calcium carbonate were $612^{\circ}C$, $748^{\circ}C$, and $890^{\circ}C$ respectively. As the heating rate of the calcium carbonate increased from $5^{\circ}C$/min to $20^{\circ}C$/min, the peak temperature increased from $719^{\circ}C$ to $782^{\circ}C$. The activation energies of the calcium carbonate calculated by the methods of Kissinger and Freeman-Carroll were 40.15 kcal/mol and 43.47 kcal/mol, respectively.

• Geomechanics and Engineering
• /
• v.13 no.3
• /
• pp.371-384
• /
• 2017

Physical and mechanical properties of rocks are of interest in many fields, including materials science, petrophysics, geophysics and geotechnical engineering. Uniaxial compressive strength UCS is one of the key mechanical properties, while density and porosity are important physical parameters for the characterization of rocks. The economic interest of carbonate rocks is very important in chemical or biological procedures and in the field of construction. Carbonate rocks exploitation depends on their quality and their physical, chemical and geotechnical characteristics. A fast, economic and reliable technique would be an evolutionary advance in the exploration of carbonate rocks. This paper discusses the ability of ultrasonic wave velocity to evaluate some mechanical and physical parameters within carbonate rocks (collected from different regions within Tunisia). The ultrasonic technique was used to establish empirical correlations allowing the estimation of UCS values, the density and the porosity of carbonate rocks. The results illustrated the behavior of ultrasonic pulse velocity as a function of the applied stress. The main output of the work is the confirmation that ultrasonic velocity can be effectively used as a simple and economical non-destructive method for a preliminary prediction of mechanical behavior and physical properties of rocks.

• Korean Chemical Engineering Research
• /
• v.47 no.3
• /
• pp.373-379
• /
• 2009

Cesium carbonate was used as an adsorbent to capture carbon dioxide from gaseous stream of carbon dioxide, nitrogen, and moisture in a fixed-bed to obtain the breakthrough data of $CO_2$. The deactivation model in the non-catalytic heterogeneous reaction systems is used to analyze the sorption kinetics among carbon dioxide, carbonate, and moisture using the experimental breakthrough data. The experimental breakthrough data are fitted very well to the deactivation model than the adsorption isotherm models in the literature.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.20 no.4
• /
• pp.371-382
• /
• 2022

Carbonates are inorganic ligands that are abundant in natural groundwater. They strongly influence radionuclide mobility by forming strong complexes, thereby increasing solubility and reducing soil absorption rates. We characterized the spectroscopic properties of Am(III)-carbonate species using UV-Vis absorption and time-resolved laser-induced fluorescence spectroscopy. The deconvoluted absorption spectra of aqueous Am(CO₃)₂^- and Am(CO₃)₃^3- species were identified at red-shifted positions with lower molar absorption coefficients compared to the absorption spectrum of aqua Am³⁺. The luminescence spectrum of Am(CO₃)₃^3- was red-shifted from 688 nm for Am³⁺ to 695 nm with enhanced intensity and an extended lifetime. Colloidal Am(III)-carbonate compounds exhibited absorption at approximately 506 nm but had non-luminescent properties. Slow formation of colloidal particles was monitored based on the absorption spectral changes over the sample aging time. The experimental results showed that the solubility of Am(III) in carbonate solutions was higher than the predicted values from the thermodynamic constants in OECD-NEA reviews. These results emphasize the importance of kinetic parameters as well as thermodynamic constants to predict radionuclide migration. The identified spectroscopic properties of Am(III)-carbonate species enable monitoring time-dependent species evolution in addition to determining the thermodynamics of Am(III) in carbonate systems.

• Nuclear Engineering and Technology
• /
• v.55 no.2
• /
• pp.391-407
• /
• 2023

This article provides a survey of wet (aqueous) methods for recovery, separation, and purification of uranium from fission products in carbonate solutions during the reprocessing of spent nuclear fuel and methods for removal of radionuclides from alkaline radioactive waste. The main methods such as selective direct precipitation, ion exchange, and solvent extraction are considered. These methods were compared and evaluated for reprocessing of spent nuclear fuel in carbonate media according to novel alternative non-acidic methods and for treatment processes of alkaline radioactive waste.

• Journal of Bio-Environment Control
• /
• v.7 no.2
• /
• pp.130-138
• /
• 1998

This experiment was conducted to study the effect of ethephon(100mg.L$^{-1}$ ) and calcium carbonate (10000mg.L$^{-1}$ ) on the acceleration of peel coloration of ‘Miyagawa Early’ Satsuma Mandarin in the plastic house. The foliar application treatments were conducted once. twice or 3 time at intervals of 15 days from degreening of the fruit apex. Peel coloration of a value by spraying ethephon ＋ clef-non was increased with treatment frequency. The a/b values ran similar to this trend. As a result of this, peel coloration was accelerated by foliar application of ethephon ＋ clef-non. Glucose and fructose did not differ significantly among foliar application frequencies. Sucrose and total sugar increased as foliar application frequency increased, but there was no significant di(ference among foliar application frequency group. The brix values were higher than 12˚BX in all treatments. However, a distinct difference between the control Brix value and the values for the treatment groups was found only in the level 3 frequency group.

• Resources Recycling
• /
• v.27 no.4
• /
• pp.29-35
• /
• 2018

In this study, the electrochemical redox behavior of neodymium in non-aqueous electrolytes was investigated to confirm the possibility of neodymium metallurgy at room temperature. The non-aqueous electrolytes include ionic liquids such as $[C_4mim]PF_6$, $[C_4mim]Cl$, and $[P_{66614}]PF_6$, ethanol which are highly soluble in neodymium salts, and mixed electrolytes based on carbonate with highly electrochemical stability. The electrochemical redox properties of neodymium were better than those of other electrolytes in the case of the mixed electrolyte based on ethylene carbonate (EC)/di-ethylene carbonate (DEC). Ethanol was added to improve the physical properties of the mixed electrolyte. Thorough the analysis about ionic conductivity of EC/DEC ratio, ethanol content and $NdCl_3$ concentration, the best electrolyte composition was 50 vol% content of ethanol and 0.5 M of $NdCl_3$. Using cyclic voltametry and linear sweep voltametry, a current peak estimated at -3.8 V (vs. Pt-QRE) was observed as a limiting current of neodymium reduction. Potentiostatic electrolysis for 18 hours at room temperature at -6 V (vs. Pt-QRE) confirmed that metallic neodymium was electrodeposited.

• Journal of Periodontal and Implant Science
• /
• v.28 no.1
• /
• pp.87-102
• /
• 1998

The purpose of this stuffy was to assess and compare the osseous responses to implanted particles of porous synthetic HA (Interpore $200^{(R)}$, Interpore International, U.S.A.), resorbable natural bovine derived HA (Bio-$oss^{(R)}$, Gestlich Pharma, Switzerland) and calcium carbonate(Biocoral $450^{(R)}$, Inoteb, France) in bone defects. Four calvarial defects of 2.5mm diameter were created in earth of 16 Sprague-Dawley rats. The experimental materials were subsequently implanted hi three defects, leaving the fourth defect for control purpose. Four animals were earth sacrificed at 3 days, 1week, 2weeks and 4 weeks after surgery. The tissue response was evaluated under light microscope. Overall, histologic responses showed that all the particles were well tolerated and caused no aberrent tissue responses. There were difference in the amount of newly formed bone at the experimental sites and control site. There was more new bone formation associated with calcium carbonate site. In addition, the calcium carbonate site displayed multinucleated giant cells surrounding calcium carbonate particles after the 1st week, and osteoid tissue within the particle after the 2nd week. After 4 weeks, calcium carbonate particles were resorbed and replaced with new bone. The healing of the natural bovine derived HA site was similar to that of porous synthetic HA, except that new bone growth between the two particles have progressed more in the former site after the 2nd week. In the natural bovine derived HA site, the particle was surrounded by newly formed bone after the 4th week. After 4 weeks, the control site showed more mature bone than other sites. In conclusion, the grafted site were better in new bone formation than non-grafted sites. In particular the calcium Carbonate site showed the ability of osteoinduction and natural bovine denver HA showed osteoconduction in rat calvarial defects. This suggest that calcium carbonate and natural bovine derived HA could enhance the regenerative potential in periodontal defects.

• Applied Chemistry for Engineering
• /
• v.3 no.3
• /
• pp.522-526
• /
• 1992

Carbonation process of an aqueous solution of $Ca(OH)_2$ with $CO_2$ gas at $10^{\circ}C$ has been studied to investigate the formation and transformation processes of amorphous calcium carbonate. It was suggested that the amorphous calcium carbonate consisting of spherical particles with the diameter in the range of $0.02{\sim}0.05{\mu}m$ be a non-stoichiometric $CaCO_3$ phase containing small amounts of $H_2O$ and small incorporations of $HCO^-_3$. Amorphous $CaCO_3$ is unstable in the aqueous solution and converts to calcite, and its morphology depends on the carbonate species present in the slurry such that with [$CO_3^{2-}$] prevailing, chain-like calcite composed of ultrafine colloidal particles and with [$HCO^-_3$] prevailing, rhombohedral particles of calcite are formed respectively. Therefore, morphological control of calcium carbonate crystals could be expected by the adequate controls of transformation process of the amorphous calcium carbonate.