• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.5
• /
• pp.549-557
• /
• 2006

The characteristics of supercritical water oxidation have been studied to decompose the waste anionic exchange resins which were produced from a power plant. The waste resins from a power plant were mixture of anionic and cationic exchange resins. The waste anionic exchange resins had been separated from the waste resins using a solid-liquid fluidized bed. It was confirmed that the cationic exchange resins were not included in the separated anionic exchange resins by the elemental and thermogravimetric analysis. A slurry of anionic exchange resins which could be fed continuously to a supercritical water oxidation apparatus by a high pressure pump was prepared using a wet ball mill. Although the COD of liquid effluent had been reduced more than 99.9% at 25.0 MPa and $500^{\circ}C$ within 2 min, the total nitrogen content was reduced only 41%. The addition of nitric acid to the slurry could reduce the total nitrogen content in treated water. The central composite design as a statistical desist of experiments had been applied to optimize the conditions of decomposing anionic resin slurry by means of the COD and total nitrogen contents in treated waters as the key process output variables. The COD values of treated waters had been reduced sufficiently to $99.9{\sim}100%$ af the reaction conditions of $500{\sim}540^{\circ}C$, 25.0 MPa within 2 min. The effects of temperature and nitric acid concentration on COD were not significant. However, the effect of nitric acid concentration on the total nitrogen was found to be significant. The regression equation for the total nitrogen had been obtained with nitric acid concentration and the coefficient of determination($r^2$) was 95.8%.

• Journal of Korean Society of Forest Science
• /
• v.36 no.1
• /
• pp.26-32
• /
• 1977

Press drying was used on sapwood and heartwood of oak (Qercus acutissima Carruthers) to find profitable means of drying low grade logs. This study was designed to investigate the process of press drying considering core temperature, current moisture content, drying rate, drying time, final moisture content, dimensional change and drying defects. The drying tests were conducted using 1.5 centimeter thick material at platen temperature of $175^{\circ}C$ and pressure of 35psi. The results were summarized as fallows. 1. Core temperature was divided into three stages of drying characterized by initial heating period, plateau temperature, and period of rising core temperature. Plateau temperature of heartwood material was higher and longer than that of sapwood material. 2. The predicting equation for change in drying rate of sapwood material was log y=-2.7925-0.0811x as function of time. That of heartwood material was log y=-3.3382-0.0468x. 3. Sapwood material reduced the moisture content from 59 to 2.5 percent in 45minutes. Heartwood material reduced the moisture content from 64 to 3.3 percent in 55 minutes. 4. Shrinkage during press drying were 20.4 percent in thickness direction and 2.5 percent in width direction. Recovery on equilibrium conditioning at 65 percent relative humidity and temperature of $20^{\circ}C$. were 11.4 percent in thickness direction and 49.4 percent in width direction. 5. Heartwood material developed severe honeycombing and moderate checking. The sapwood material dried without honeycombing, checking and collapse. All material kept wood flat.

• The korean journal of orthodontics
• /
• v.34 no.2 s.103
• /
• pp.131-142
• /
• 2004

The movement of tooth-bone segments by osteotomy can simultaneously shift tooth and surrounding alveolar bone in a relatively short period. The purpose of this study was to evaluate the tissue changes in pulp, periodontal ligament, and alveolar bone in rapid tooth-bone movement with osteotomy. The mandibular 3rd premolar of a dog was extracted and cortical bones of the buccal and lingual area were eliminated, and then cortical bones around the mesial and distal area of root, and below the root apex of the mandibular 4th premolar were osteotomized. After a one-week latency period, a tooth-borne distraction device was activated for 6 days. And pulp, periodontal ligament and alveolar bone were evaluated clinically, radiologically, histologically and immunohistochemically at 0, 1, 2, 4, 6, 8 weeks of the consolidation Period and conclusions were roached as follows. 1. Latency period didn't affect total amount or tooth movement and healing process of tissue during consolidation period. 2. Bone formation continued through 8 weeks of consolidation in distracted side, with a high peak at 1-2 weeks, and the lowest at 6-8 weeks or consolidation. 3. At 1 week of consolidation, alveolar bone resorption, osteoclast appearance and inflammatory cell infiltration were the most active, and dentinoclasts characteristically appeared on the pulp and pressure side of the periodontal ligament. 4. The expression of $TGF-\beta$ was area-specific, as it was strong-positive at bone matrix, osteoblast osteoclast of alveolar bone, and dentinoclast inside pulp, but weak in pulp, cementoblast and acellular cementum. 5. The expression of $TGF-\beta$ was generally observed at the initial 1-2 weeks of consolidation at vessels, periodontal ligament cells, and osteoblast near alveolar bone on the distraction side of the periodontal ligament, and was significantly decreased after 6 weeks of consolidation.

• Journal of the Korean Society of Safety
• /
• v.7 no.2
• /
• pp.63-70
• /
• 1992

The aim of this research is to obtain a basic quantitative understanding of the effect of a noncondensable gas on the absorption of water vapor by a $H_2O$ / LiBr combination with n-octanol as the surfactant. Nonflowing aqueous solutions of LiBr (40,45,50 mass％) were exposed to saturated water vapor following the addition of an n-octanol sufactant (0.01 and 0.6 mass％). A small amount of a noncondensable gas (air) was allowed into the absorber (0.03 volume％) and its effect was analyzed by measuring the amount of water vapor absorbed. This study will aid to predict the performance of heat pump and safety operating condition when the noncondensable gas is not allowed in the absorber The results indicate that, in the presence of small amounts of a noncondensable gas, vapor absorption enhancement ratios are less than half o( those obtained under the same experimental conditions when a noncondensable gas is not present (1). The presence of a noncondensable gas causes the partial vapor pressure of air to increase at the vapor / liquid interface, which results in an instability of vapor absorption rate nd. hence, in an inhibition of interfacial disturbance.

• Tuberculosis and Respiratory Diseases
• /
• v.44 no.6
• /
• pp.1326-1331
• /
• 1997

Background : Weaning is the process of switching a patient from mechanical ventilator to spontaneous breathing. A number of different weaning techniques can be employed. At recent study, conventional spontaneous breathing trial was superior to other techniques, such as intermittent mandatory ventilation(IMV) or pressure support ventilation(PSV). But adequate observation time of the spontaneous breathing trial was not determined. We reported the effectiveness of weaning and extubation following a 60 minutes spontaneous breathing trial with simple oxygen supply through the endotrachial tube. In this study, we tried to shorten the spontaneous breathing time from 60 minutes to 30 minutes. If weaning success was predicted after 30 minutes spontaneous breathing, extubation was done without reconnection with ventilator. Methodes : Subjects consisted of 42 mechanically ventilated patients from August 1994 to July 1995. The weaning trial was done when the patients recovered sufficiently from respiratory failure that originally required ventilatory assistance, the patients became alert and showed stable vital sign, and arterial $O_2$ tension was adequated($PaO_2$ > 55 mmHg) with less than 40% of inspired oxygen fraction. We conducted a careful physical examination when the patients was breathing spontaneously through the endobronchial tube for 30 minutes. We terminated the trial if a patients was any of following signs of distress; cyanosis, diaphoresis, tachypnea(above 30 breaths per minute), and extreme tachycardia. Patients who had none of this features during spontaneous breathing for 30 minutes were extubated promptly. Result : 17 weaning trials of 15 patients were done in 42 mechanically ventilated patients. Successful weaning and extubation was possible in 14 trials of total 17 trials. In this 14 patients, 8 patients were extubated after 30 minutes spontaneous breathing, 3 patients were extubated after 60 minutes spontaneous breathing, and 3 patients needed over 3 hours for extubation from weaning. We found similar overall success rate compared with weaning following a 60 minutes spontaneous breathing trial. Conclusion : From the result of present study, we believe that weaning and extubation from mechanical ventilation following a 30 minutes spontaneous breathing with $O_2$ supply through the endotracheal tube is a simple and effective method.

• Journal of the Korean Vacuum Society
• /
• v.18 no.1
• /
• pp.66-72
• /
• 2009

The detection methods are required to monitor and diagnose the abnormality on the insulation condition inside a gas-insulated switchgear (GIS). Due to a good sensitivity to the products decomposed by partial discharges (PDs) in $SF_6$ gas, the development of a SWNT gas sensor is actively in progress. However, a few numerical studies on the diffusion mechanism of the $SF_6$ decomposition products by PD have been reported. In this study, we modeled $SF_6$ decomposition process in a chamber by calculating temperature, pressure and concentration of the decomposition products by using a commercial CFD program in conjunction with experimental data. It was assumed that the mass production rate and the generation temperature of the decomposition products were $5.04{\times}10^{-10}$ [g/s] and over 773 K respectively. To calculate the concentration equation, the Schmidt number was specified to get the diffusion coefficient functioned by viscosity and density of $SF_6$ gas instead rather than setting it directly. The results showed that the drive potential is governed mainly by the gradient of the decomposition concentration. A lower concentration of the decomposition products was observed as the sensors were placed more away from the discharge region. Also, the concentration increased by increasing the discharge time. By installing multiple sensors the location of PD is expected to be identified by monitoring the response time of the sensors, and the information should be very useful for the diagnosis and maintenance of GIS.

• Journal of the Korean Vacuum Society
• /
• v.17 no.6
• /
• pp.538-543
• /
• 2008

Recently a nano-scale diamond is possible to manufacture forms of powder(below 100 nm) by new processing of explosion or deposition method. Using a sintering of nano-scale diamond is possible to manufacture of grinding tools. We have need of a processing development of coated uniformly inorganic to prevent an abnormal grain growth of nano-crystal and bonding obstacle caused by sintering process. This paper, in order to improve the sintering property of nano-scale diamond, we coated ZnO thin films(thickness: $20{\sim}30\;nm$) in a vacuum by ALD(atomic layer deposition) Economically, in order to deposit ZnO all over the surface of nano-scale diamond powder, we used a new modified fluidized bed processing replaced mechanical vibration effect or fluidized bed reactor which utilized diamond floating owing to pressure of pulse(or purge) processing after inserted diamond powders in quartz tube(L: 20 mm) then closed quartz tube by porosity glass filter. We deposited ZnO thin films by ALD in closed both sides of quartz tube by porosity glass filter by ALD(precursor: DEZn($C_4H_{10}Zn$), reaction gas: $H_2O$) at $10^{\circ}C$(in canister). Processing procedure and injection time of reaction materials set up DEZn pulse-0.1 sec, DEZn purge-20 sec, $H_2O$ pulse-0.1 sec, $H_2O$ purge-40 sec and we put in operation repetitive 100 cycles(1 cycle is 4 steps) We confirmed microstructure of diamond powder and diamond powder doped ZnO thin film by TEM(transmission electron microscope) Through TEM analysis, we confirmed that diamond powder diameter was some $70{\sim}120\;nm$ and shape was tetragonal, hexagonal, etc before ALD. We confirmed that diameter of diamond powders doped ZnO thin film was some $70{\sim}120\;nm$ and uniform ZnO(thickness: $20{\sim}30\;nm$) thin film was successfully deposited on diamond powder surface according to brightness difference between diamond powder and ZnO.

• Korean Journal of Food Science and Technology
• /
• v.37 no.2
• /
• pp.183-188
• /
• 2005

Effects of co-solvent polarity, citric acid, pressure, temperature, run time, and co-solvent ratio on extraction of major flavonoids from Lonicera Flos were investigated using supercritical fluid $CO_{2}(SF-CO_{2})$. HPLC analysis revealed addition of pure methanol resulted in low extraction yield of major flavonoids, luteoloin (Lu), Quercetin (Qu), Apigenin (Ap). Under same condition, as co-solvent polarity increased, yields of major flavonoids increased gradually, At optimum co-solvent extraction condirion of 60% aqueous methanol (10%, v/v), yields of Lu, Qu, and Ap were 42.09, 28.18, and 3.49 mg/100 g, respectively. Addition of citric acid to 60% aqueous methanol gave higher, with addition of 1% citrie acid resulting in highest yields of 63.2 (Lu), 39.35 (Qu), and 5.79 (Ap) mg/100 g. Optimum extraction conditions of major flavonoids were 200 bar, $50^{\circ}C$, 60 min, and $CO_{2}$-methanol-water(20: 1.8: 1.2).

• Analytical Science and Technology
• /
• v.26 no.3
• /
• pp.165-173
• /
• 2013

To establishment of PT Program for Indoor air quality field that manufacture of confidential development PTMs (proficiency testing materials) and examined of proficiency testing evaluation included sampling process whether or not that is valid. Confirmation of homogeneity and stability of PTMs prepared. PTMs were confirmed to be homogeneous enough to be used as proficiency testing materials since withinbottle homogeneities of the RMs were lower than 0.3 times of targeted standard deviation of proficiency testing. The result of this study showed that the Robust RSD of proficiency testing for VOCs (volatile organic compounds) appeared 23~43% in concentration of 50~320 ${\mu}g/m^3$ for Method A(Distribution by adsorption in Tenax-tube of VOCs), but less 13~42% in concentration of 200~1200 ${\mu}g/m^3$, 16~31% in concentration of 100~450 ${\mu}g/m^3$ for Method B (distribution by VOCs of gas phase in 10L Tedalr bag), C (directly sampling of cylinder with high pressure) respectively. The result of this study showed that method C with sampling is most adequate to the proficiency testing for VOCs in indoor air.

• The Korean Journal of Archival Studies
• /
• no.8
• /
• pp.137-180
• /
• 2003

The term 'Business Archives' is not familiar with us in our society. Some cases can be found that materials are collected for publishing the history of a firm on commemoration of some decades of its foundation. However, the appropriate management of these collected materials doesn't seem to be followed in most of companies. The Records and archives management is inevitable in order to maximize the utility of Information and knowledge in the business world. The interest in records management has been grown, especially in the fields of business management and information technology. However, the importance of business archives hasn't been conceived yet. And also no attention has been paid to the business archives as social resources and the responsibility of the society as a whole for their preservation. The company archives doesn't have a long history in Germany although the archives of the nation, the aristocracy, communes and churches have a long tradition. However the company archives of Krupps which was established in 1905, is regarded as the first business archives in the world, It means that Germany has taken a key role to lead the culture of business archives. This paper focuses on the process of the establishment of business archives in Germany and its characteristics. The business archives in Germany can be categorized in three types: company archives, regional business archives and branch archives. It must be noted here that each type of these was generated in the context of the accumulation of the social resources and its effective use. A company archives is established by an individual company for the preservation of and use of the archives that originated in the company. The holdings in the company archives can be used as materials for decision making of policies, reporting, advertising, training of employees etc. They function not only as sources inside the company, but also as raw sources for the scholars, contributing to the study of the social-economic history. Some archives of German companies are known as a center of research. A regional business archives manages materials which originated m commerce chambers, associations and companies in a certain region. There are 6 regional business archives in Germany. They collect business archives which aren't kept in a proper way or are under pressure of damage in the region for which they are responsible. They are also open to the public offering the sources for the study of economic history, social history like company archives, so that they also play a central role as a research center. Branch business archives appeared relatively late in Germany. The first one is established in Bochum in 1969. Its general duties and goals are almost similar with ones of other two types of archives. It has differences in two aspects. One is that the responsibility of the branch business archives covers all the country, while regional business archives collects archives in a particular region. The other is that a branch business archives collects materials from a single industry. For example, the holdings of Bochum archives are related with the mining industry. The mining industry-specialized Bochum archives is run as an organization in combination with a museum, which is called as German mine museum, so that it plays a role as a cultural center with the functions of exhibition and research. The three types of German business archives have their own functions but they are also closely related each other under the German Association of Business Archivists. They are sharing aims to preserve primary materials with historical values in the field of economy and also contribute to keeping the archives as a social resources by having feed back with the public, which leads the archives to be a center of information and research. The German case shows that business archives in a society should be preserved not only for the interest of the companies, but also for the utilities of social resources. It also shows us how business archives could be preserved as a social resource. It is expected that some studies which approach more deeply on this topic will be followed based on the considerations from the German case.