• The Journal of Engineering Geology
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• v.25 no.1
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• pp.1-8
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• 2015

Deep geological disposal is the preferred storage method for high-level radioactive waste, because it ensures stable long-term storage with minimal potential for human disruption. Because of the risk of groundwater contamination, a buffer of steel and bentonite layers has been proposed to prevent the leaching of radionuclides into groundwater. Quartz is one of the most common minerals in earth's crust. To understand how deformation and dissolution phenomena affect waste disposal, here we study quartz samples at pressure, temperature, and pH conditions typical of deep geological disposal sites. We perform a dissolution experiment for single quartz crystals under different pressure and temperature conditions. Solution samples are collected and the dissolution rate is calculated by analyzing Si concentrations in a solution excited by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). After completing the dissolution experiment, deformation of the quartz sample surfaces is investigated with a confocal laser scanning microscope (CLSM). An empirical formula is introduced that describes the relationship between dissolution rate, pressure, and temperature. These results suggest that bentonite layers in engineering barrier systems may be vulnerable to thermal deformation, even when exposed to higher temperatures on relatively short timescales.

• Proceedings of the Korean DIstribution Association Conference
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• 2005.05a
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• pp.87-110
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• 2005

So far, the studies on the dissolution of relationship have regarded dissolution intention as the final consequence, therefore have not investigated phenomena after the formation of dissolution intention. This study is a seminal work which shows the mechanisms of deterioration of dissolution intention toward complete dissolution. So, this study has the scope from the formation of dissolution intention and to the right before of the complete dissolution. This study has investigated the consequences of dissolution intention(increasing opportunism, decreasing transaction specific investment, and decreasing cooperation) and the relationships of them empirically. As the result of hypotheses test using data collected from 179 newspaper branch office samples, all hypotheses are supported. Dissolution intention has the positive effect on opportunism and negative effect on transaction specific investment. Opportunism decrease transaction specific investment and cooperation. And, transaction specific investment has the positive effect on cooperation. Finally, the authors discussed the theoretical contributions, managerial implications, and limitations of this study and presented the future research directions.

• Journal of Pharmaceutical Investigation
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• v.30 no.2
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• pp.119-125
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• 2000

In an attempt to develop a non-aqueous liquid formulation of practically insoluble biphenyl dimethyl dicarboxylate (DDB), dissolution and permeation studies were performed. Various non-aqueous DDB solutions were formulated and filled into empty hard capsules. Dissolution rates of a new formulation were compared with those of commercially available DDB preparations using one and eight dose units. Dissolution rates after 2 hr of DDB tablets (DDB 25 mg), hard capsules (DDB 7.5 mg) and soft capsules (DDB 7.5 mg) on market and new formulation (DDB 7.5 mg) were 6.3, 15.0, 84.5 and 98.0%, respectively. Higher doses (8 units) resulted in a supersaturation within one hr of dissolution, and dissolved amounts were reduced markedly. Due to the saturation and precipitation, a directly proportional dose-dissolution relationship was not observed. The addition of copolyvidone and/or glycyrrhizic acid ammonium salt to DDB solution in polyethylene glycol 300 and 400 inhibited the formation of precipitates during dissolution and markedly enhanced the rabbit duodenal permeation of DDB. From the site-specific gastrointestinal permeation studies, it was found that permeation rates of DDB after mixing of non-aqueous DDB solutions with aqueous buffered solutions were faster in the order of $rectal\;<\;colonic\;{\risingdotseq}\;ileal\;{\risingdotseq}\;duodenal\;<\;jejunal\;<\;gastric$.

• Journal of Pharmaceutical Investigation
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• v.19 no.3
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• pp.131-136
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• 1989

This study was attempted to investigate the dissolution rate and the bioavailability after oral administration of commercially available aspirin tablets in normal volunteers. The dissolution test was conducted in artificial gastric juice using basket method with three aspirin preparations (A, B and C) which were chemically equivalent. The results were as follows; The dissolution rate was higher in the order of three different brand B>A >C. Area under the blood concentration and peak blood concentration were larger in the order of brand A>B>C. Absorption rate constant and peak time were larger in the order of brand B>A>C, and there was a little difference in elimination rate constant and biological half-life. The correlation of the dissolution rate and absorption rate constant, as well as correlation of the dissolution rate and peak time showed significant linear relationship respectively. From the results of this experiment, it can be concluded that the bioavailability of aspirin tablets showed much difference according to commercial preparations, and that the bioavailability of aspirin tablets in human may be predicted from the results of dissolution rate studies.

• Journal of Pharmaceutical Investigation
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• v.17 no.3
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• pp.135-139
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• 1987

This study was attempted to investigate the dissolution rate and the bioavailability of commercially available sulfamethoxazole and trimethoprim (SMX-TM) tablets in rabbits. The dissolution test was conducted in artificial gastric juice by basket method with eight SMX-TM tablets which were chemically equivalent. According to the dissolution rate, SMX-TM tablets were divided into four groups, such as rapid, intermediate, slow and very slow groups for the bioavailability test in rabbits. The results were as follows: 1) The dissolution rate of brand A was most rapid but brand H was most slow in artificial gastric juice. 2) Area under the blood concentration curve was larger in the order of brand A > C > E > H in rabbits. 3) There was a little difference in pharmacokinetic parameters such as biological half life, absorption rate constant and $t_{max}$. 4) The relationship between the dissolution rate and relative bioavailability was significant in brand A, C, E and H. From the results of this experiment, the bioavailability of SMX-TM tablets in rabbits may be predicted from the results of dissolution rate studies.

• Journal of Pharmaceutical Investigation
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• v.22 no.1
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• pp.55-62
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• 1992

In order to measure the bioavailability of Coptidis Rhizoma preparations, berberine was extracted by the mixture (1:1 v/v) of methanol and water from Coptidis Rhizoma and formulated into pills with some excipients. Disintegration time, dissolution rate, intestinal absorption rate, antibacterial effect, and serum concentration were measured. All pills were disintegrated about 60 minutes in gastric and intestinal juices and disintegration time did not change upon storage at $40^{\circ}C$ for 30 days. The pills manufactured using the extract which was extracted with the solvent containing dilute sulfuric acid showed faster dissolution and absorption from the small intestine than the other samples. It also showed not only the largest area under the serum concentration time curve and relative bioavailability, but also more potent antibacterial effect against gram-positive and gram-negative bacterias than the other samples. The correlation of the dissolution rate with absorption rate constant or $t_{max}$ showed a significant linear relationship.

• The Korean Journal of Franchise Management
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• v.8 no.3
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• pp.29-37
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• 2017

Purpose - In recent years, research has been conducted on the conflict resolution strategies of the franchise headquarters and the franchisees, but there is a lack of research on the factors of conflict due to the intrinsic structure, such as interdependence or hierarchical relationship, and behavioral analysis to reduce the conflict. In this study, we analyze the relationship between satisfaction and trust formed in the process and result of the business, and the result of action to dissolution intention. Research design, data, methodology - For these purposes, the author developed the proposed model and several hypotheses. In this model, conflict resolution strategies consist of five dimensions such as avoiding, forcing, cooperating, obliging, and compromising strategy. And, this model proposed that onflict resolution strategies are antecedents of procedure quality, behaviour quality and dissolution intention are consequences of conflict resolution strategies. The data were collected from April 1 to April 15, 2013. Because this study examined franchise industries from the franchisee perspective, we contacted franchisee store owner and managers located in Seoul and Gyeonggi Province. Interviewers trained contacted a total of 483 franchisees, and 400 franchisees responded. Out of 400 respondents, 2 respondents were deleted due to missing information. Thus, a total of 398 franchisee were used for this study. he data were analyzed using frequency analysis, confirmatory factor analysis, correlation analysis, and structural equational modeling with SPSS 24.0 and Amos 23.0 statistical program. Results - The findings can be summarized as follows: First, franchisor conflict resolution activities have significant effects on procedure quality. Second, procedure quality has a significant effect on behavior quality. Finally, behavior quality has a significant effect on dissolution intention. Conclusions - In this study, we investigated the relationship between conflict resolution behavior, procedural quality, behavior quality and dissolution intention. As a result, the franchisers should strive to resolve conflicts not only in solving simple problems with franchisees, but also in a longer term perspective. We also found that the procedural aspects of resolving conflicts should not be ignored. If the trust and satisfaction of each other increase during the process of resolving the conflict, it will positively affect the satisfaction and trust in resolving the conflict. This is also because it serves to lower the intention of termination. However, there is a limitation that it is targeted only to the restaurant franchise, and it is necessary to study the conflict resolution behavior depending on the type of conflict.

• Economic and Environmental Geology
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• v.50 no.6
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• pp.509-515
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• 2017

Quartz is the most abundant mineral in the Earth's continental crust. Therefore, understanding of quartz dissolution and precipitation is very important to know about weathering processes and interactions between rocks and water in hydrothermal and metamorphic environments. This paper presents a basic review on the research about quartz dissolution mechanism under various physico-chemical conditions. We rearranged the relationship between each physico-chemical factor and dissolution mechanism from the results of previous researchers in this paper. From this result, we understood that quartz dissolution and precipitation are affected by each factor such as temperature, pH, and applied stress conditions at contact point. In particular, we recognized that the high pH and temperature conditions have different anion concentrations on mineral's surface. As a result, high pH and temperature conditions have a better effect than applied stress condition to the quartz dissolution mechanism.

• Journal of Pharmaceutical Investigation
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• v.6 no.3
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• pp.58-69
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• 1976

It is well established that dissolution is freruently the rate limiting step in the gastrointestinal absorpton of a drug from a solid dosage from. The relationship between the dissolution rate and absorption is particularly distinct when considering drugs of low solubility. Consequently, numerous attempts have been made to modify the dissolution characteristics of poorly water soluble drugs. Since dissolution rate is directly proportional to surface area, one may increase the rate by decreasing the particle size of the drug. Levy has considered a number of methods by which a drug may be presented to the GI fludids in finely divided from. The direct method is the utilization of microcrystalline or micronized particles. A second method involves the administration of solutions from which, upon dilution with gastric fluids, the dissolved drug will precipitate in the form of very fine particles. A more unique way of obtaining microcrystalline dispersions of a drug has been ercently suggested by Sekiguchi et al. They have first proposed the formation of a eutectic mixture of a poorly water soruble drug with a physiologically inert, easily soluble carrier. When such systems are exposed to water or GI fluids, the soluble carrier will dissolve rapidly and the finely dispersed drug particles will then be released. It has been suggested by Shefter and Higuchi that the formation of crystalline solvate could be a powerful tool in affecting rapid disslution of highly insoluble substances. Goldberg et al. have noted that the formation of solid solution could reduce the particle size to a minimum and increase the dissolution rate as well as the solubility of the durgs. It has also been shown that the rates of solution of drugs were appreciably increased by coprectipitating the drug with soluble polymers. The increase was found to be sensitive to the method of preparation, the molecular weight of polymer and the particular ratio of drugs to polymer. Although several investigations have demontrated that the solubility and/or dissolution rates of drugs can be increased in this manner, little information is available in the literature related to the in vivo absorption pattern of drugs orally administered as PVP coprecipitates. Recently, however, it was demonstrated that both the rate and extent of absorption of the insoluble drug could be markedly enhanced when orally administered to rats in the form of a coprecipitate with PVP. The purpose of the present investigation was to ascertain the general appility of soluble polymer coprectation technique as a method for enhancing the in vitro dissolution rate of hydrophobic indomethacin. To accomplish this aim, the dissolution characteristics of pure indomethacin, indomethcin-polymer physical mixtures and indomethacin-polymer coprecipitates were quantitatively studied by comparing their relative dissolution rates. The solubility and dissolution behavior of these systems were also examined.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3717-3722
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• 2021

In this study, the recovery rates of the dissolution method for radioactivity analysis of expandable polystyrene (EPS) with a liquid scintillation counter (LSC) using tetrahydrofuran (THF), toluene, and acetone as solvents were estimated. The detection efficiency calibration curve for each solvent was derived. Two methods-the volumetric ratio method and the quenching agent method-were used to prepare quench source sets, and calibration curves were derived by linking the data from the two quench source sets. The R² value of the calibration curve for THF was found to be 0.984. The relationship between the mass of dissolved EPS and the quench level was estimated: the quench level increased as the mass of dissolved EPS increased. Premix and postmix dissolution methods were tested. The recovery rates using THF with the premix method were 84.9 ± 0.9% and 96.5 ± 1.5% for ³H and ¹⁴C, respectively. Furthermore, the stability of the recovery rate over time when using THF was evaluated. The dissolution method with the premixed solution exhibited a more stable recovery rate over time. The dissolution methods were found to be applicable for analysis using LSC, and THF was found to be the most suitable solvent for the proposed method.