• Title, Summary, Keyword: 2-way condensation

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Development of drying apparatus using 2-way condensation for marine products (2방식 응축을 이용한 수산물 건조 장치 개발)

  • Hwang, Jea-Ho
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.42 no.4
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    • pp.259-266
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    • 2006
  • In this study, the 2-way condensation system was designed applying air-to-air heat pump to dry a marine product such as squid in the winter. And to be made the drying apparatuses by this system, there are two kinds of type, A type, was set a compressor outside of the drying apparatus, B type, was set a compressor in the drying room. And then the variations of temperature in drying room were measured to compare the heating performance of the drying apparatuses between A type and B type at $-6.5^{\circ}C$, outdoor temperature. The temperature of the drying room for B type was increased to $36^{\circ}C$ but the temperature of the drying room for A type was not increased to $36^{\circ}C$, to be increased to $20^{\circ}C$.

APICAL SEALING OF THERMAFIL OBTURATORS IN CURVED CANALS (만곡근관에서 Thermafil의 근단폐쇄성에 관한 실험적 연구)

  • Ha, Joo-Hee;Choi, Gi-Woon
    • Restorative Dentistry and Endodontics
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    • v.20 no.2
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    • pp.671-684
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    • 1995
  • The purpose of this study was to compare the apical sealing ability, overfilling and obturation of lateral canals using two gutta-percha techniques: Thermafil obturators and cold lateral condensation. Eighty numbered epoxide blocks with one major and five lateral canals were divided into four experimental groups and obturated according to experimental groups. Four experimental groups were as follows: Group 1 : Filling with Thermafil plastic obturators and sealer(ThermaSeal) Group 2 : Filling with Thermafil plastic obturators only, without sealer(ThermaSeal) Group 3 : Fillng using lateral condensation with sealer(AH-26) Group 4 : Fillng using lateral condensation without sealer(AH-26) All the blocks were stored in 100% relative humidor at room temperature for 7 days. Each block was placed in centrifuge tube filled with India ink, and then centrifuged for 20 minutes at 3,000 rpm. Apical leakage was measured from the apical foramen to the most coronal level of dye penetration in millimeter under a stereoscope. The length of gutta-percha and sealer in each of the lateral canals was measured, too. The presence or absence of overfilling of gutta-percha and sealer was recorded. The data was analyzed by one-way ANOVA. The obtained results were as follows: l. Apical dye leakage was almost: not occurred in Group Willed with Thermafil and sealer) and Group 3(filled using lateral condensation with sealer), and there was no significant difference in linear leakage between two groups(p>0.01). 2. In both Thermafil and lateral condensation groups, linear leakage of Group I, 3(filled with sealer) was less than that of Group 2, 4(filled without sealer), and there was no significant difference in linear leakage between Group 1, 2, 3(p> 0.01). 3. Overfilling during obturation of Group 1, 2(filled with Thermafil) was more than Group 3, 4(filled using lateral condensation), and there was no significant difference between groups(p> 0.05). 4. Groups filled with Thermafil had significantly more gutta-percha than groups filled using lateral condensation in all lateral canals(p <0.01), the total length of gutta-percha and sealer found in all lateral canals were similar in Group 1 and Group 3.

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Effect of Urea-Formaldehyde Resin Adhesive Viscosity on Plywood Adhesion

  • Hong, Min-Kug;Park, Byung-Dae
    • Journal of the Korean Wood Science and Technology
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    • v.45 no.2
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    • pp.223-231
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    • 2017
  • This work was conducted to investigate on the effect of urea-formaldehyde (UF) resin viscosity on plywood adhesion. The viscosity of UF resin was controlled either by adjusting the condensation reaction during its synthesis to obtain different target viscosities (100, 200 and 300 mPa.s) at two levels of formaldehyde/urea (F/U) mole ratios (1.0 and 1.2) or by adding different amounts (10, 20 and 30%) of wheat flour into the resins for the manufacture of plywood. When the viscosity of UF resin increased by the condensation reaction, the adhesion strength of plywood bonded with UF resin of 1.2 F/U mole ratio consistently increased, while those bonded with the 1.0 F/U mole ratio resin slightly decreased, suggesting a difference in the adhesion in plywood. However, the adhesion strength of plywood decreased as the viscosity increased by adding wheat flour, regardless of F/U mole ratio. The manipulation of UF resin viscosity by adjusting the condensation reaction was much more efficient than by adding wheat flour in improving the adhesion performance of plywood. These results indicated that a way of controlling the viscosity of UF resin adhesives has a great influence to their adhesion in plywood.

A STUDY ON THE SEALING ABILITY OF THE THERMAFIL ENDODONTIC OBTURATION TECHNIQUE (Thermafil 충전법의 근관폐쇄성에 관한 연구)

  • Park, Chan-Je;Yo, In-Ho;Lim, Sung-Sam
    • Restorative Dentistry and Endodontics
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    • v.21 no.2
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    • pp.517-529
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    • 1996
  • The purpose of this study was to evaluate the apical sealing ability of the Thermafil endodontic obturation technique and to compare it with lateral condensation technique. 42 straight canals from extracted human anterior teeth and 42 curved canals(> $25^{\circ}$) from maxillary and mandibular molar teeth were selected. And 80 of them were divided into four groups, 20 canals respectively. The teeth in prior two groups had straight canals and the other two groups had curved canals. The rest of four canals served as positive and negative controls. After resecting anatomical crowns, all canals were prepared using a standard step-back technique. Lateral condensation was used to obturate two groups, one group of straight ones the other curved. And Thermafil obturators were also used in the same two groups. Obturated teeth were infiltrated by India ink for a week, decalcified and cleared with 5% nitric acid and methyl salicylate. The apical leakage and the frequency of filled lateral and accessory canals were measured with stereomicroscope and also apical extrusion of sealer and gutta-percha and obturation time were checked and the data were analyzed statistically(one-way ANOVA, t-test, Chi-square test). The results were as follows : 1. There was no significant difference in the degree of dye penetration between Thermafil and lateral condensation groups(p>0.05). 2. Apical extrusion of sealer and gutta-percha occurred significantly more often with Thermafil obturators in straight canals(p<0.05), but not significantly different in curved canals(p>0.05). 3. Canal obturation time with Thermafil obturators was significantly faster than lateral condensation (p<0.05). 4. The Thermafil groups showed a higher frequency of filled lateral and accessory canals than in the lateral condensation groups. But the difference was not statistically significant (p>0.05).

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A Study on the Effect of Material Properties Related to Liquid Transport on the Maximum Cumulative Condensation (벽체 구성재료의 액체 전달에 관련된 물성이 최대 누적결로량에 미치는 영향에 관한 연구)

  • Hong, Soung-Wook;Kang, Hye-Suk;Park, Chang-Young;Jang, Hyang-In
    • 한국건축친환경설비학회 논문집
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    • v.11 no.6
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    • pp.572-585
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    • 2017
  • The purpose of this study is to derive the formula which indicates influences of density, specific heat and porosity upon the calculation of the cumulative condensation amount per year inside the wall under abnormal conditions, among permeability performance of the inner-insulation wall. For this, the followings are conducted: (i) A one-dimensional wall shape composed of concrete structures, insulation materials and interior materials is established; (ii) Reflecting factors considering the spread caused by the difference in indoor and outdoor vapor pressures, i.e. thickness, thermal conductivity, and vapor resistance coefficient, the cumulative condensation amount per year, i.e. the characteristic value of the three-way factorial design method per level of each factor; 'Result 1' (iii) The maximum cumulative condensation amount per year is calculated per each level according to EN 15026 by adding the density, the specific heat and the porosity, which are factors for humid performance; and based on the foregoing, 'Result 2' (iv) the correlation with regard to the influences on the density, the specific heat, and the porosity of each material layer is derived. Through this process, the relation between the vapor diffusion performance and the humid performance is defined. The study results are as follows. (i) The pattern of comparison between the 'Result 1' and 'Result 2' is similar. (ii) The difference in density, specific heat, and porosity state quantities is not considered to be a factor affecting the diffusion of water vapor due to the difference in the partial pressure of vapor and capillary phenomenon. (iii) The increase of density, specific heat and porosity does not seem to have a proportional effect on the amount of condensation.

A Study on the Process Optimization of Microcellular Foaming Injection Molded Ceiling Air-Conditioner 4-Way Panel (초미세발포 사출성형을 이용한 천정형 에어컨 4-way 판넬의 공정 최적화에 관한 연구)

  • Kim, Joo-Kwon;Lee, Jung-Hee;Kim, Jong-Sun;Lee, Jun-Han;Kwak, Jae-Seob
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.6
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    • pp.98-104
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    • 2018
  • Deflected 4-way panels of ceiling air conditioners produced by injection molding process have caused dew condensation at the edge of products. In order to prevent this drawback with reducing weight and deformation, this study proposed renovated process adopting microcellular foaming. According to results from 2-sample t-test and analysis of variance(ANOVA), the critical factors affecting weight were melt temperature and injection speed. In addition, the vital effects on deformation were structure at the edge, mold temperature and cooling time. Optimal conditions of these parameters were derived by regressive analysis with CAE and response surface method(RSM), and then applied to an actual design and process stage to analyze performance. As a results, it clearly showed that new process improved process capability as well as reduced both weight and deformation by 18.8% and 71.9% respectively compared to the conventional method.

An Experimental Study on the Condensation Characteristics of Sea Water in the Tilted Box with Solar Radiation (태양열을 받는 경사진 육면체 내 해수의 응축특성에 관한 실험적 연구)

  • Kim, Beom-Han;Kim, Byung-Chul
    • Journal of the Korean Solar Energy Society
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    • v.31 no.4
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    • pp.27-33
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    • 2011
  • To find effective way of the production of distilled water for drought and flood with solar radiation, three boxes were made same base each 1000mm ${\times} $1000mm and tops are 45 degree. Individual boxes contained the sea water, rain water and surface water were placed at the same location and same time. Condensation of each box has been compared. On clear day production of distilled water in the box with sea water was 36% and 32% less than boxes with rain water and surface water. The maximum condensation reached when the temperature of the top and bottom parts are equal. As concentration of sea water increased production of distilled water was decreased. In the box with sea water, the surface temperature was lower than 3cm below the surface. Optimum collector area for producing distilled water 2000ml of these three boxes were $3.75m^2$

COMPARISON OF THE INFLUENCE OF CANAL CURVATURE ON THE SEALING ABILITY OF LATERAL CONDENSATION AND SYSTEM BTM (측방가압법과 System BTM를 이용한 근관충전시 근관만곡도에 따른 폐쇄효과의 비교)

  • Lim, Dong-Yeul;Lee, Hee-Joo;Hur, Buck
    • Restorative Dentistry and Endodontics
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    • v.24 no.3
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    • pp.482-489
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    • 1999
  • The purpose of this study was to compare sealing ability between lateral condensation and continuous wave of condensation in depend of root canal curvature. In this study, we divided fifty-six human molar teeth into two group in depend of Schneider method, and then subdivided them into four experimental group (each group is composed of twelve teeth) by canal curvature and obturation method, and eight teeth were served as positive and negative controls. Specimens were prepared by Quantac 2000 series file and obturated by lateral condensation or System B. Specimens were immersed in india ink for 7 days, decalcified by 10% nitric acid, dehydrated by 75, 95 and 100% alcohol in order, cleared by methyl salicylate and then measured of dye penetration with stereomicroscope(${\times}6.5$ magnification) and Image Pro plus. The data were analyzed stastically by one-way ANOVA and Scheffe test. The data were as follows: 1. The mean leakage was $0.725{\pm}1.167$ for group A, $0.813{\pm}0.921$ for group B, $0.809{\pm}0.997$ for group C, $1.111{\pm}1.147$ for group D, but no significant difference among them(p>0.05). 2. Lateral condensation had better sealing ability than continuous wave of condensation, but no significant difference among them(p>0.05). 3. There was no significant difference between root canal curvature degree and microleakage(p>0.05).

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A STUDY ON THE APICAL MICROLEAKAGE OF GLASS IONOMER ROOT CANAL SEALER (Glass Ionomer Root Canal Sealer의 치근단 미세누출에 관한 연구)

  • Lee, So-Young;Hong, Chan-Ui
    • Restorative Dentistry and Endodontics
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    • v.23 no.1
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    • pp.236-246
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    • 1998
  • The purpose of this study was to compare the degree of micro- leakage of new glass ionomer root canal sealer, Ketac-Endo(ESPE Co., Seefeld, Germany) with that of AH-26(De Trey Co., Ltd., U.S.A.). Root canal treatment using K -file, H -file, Gate Glidden drill was conducted on 49 extracted single-rooted teeth. 45 teeth were randomly divided into 3 experimental groups(15 teeth per group) and 4 teeth were used as the control group. Group 1 was used AH -26 sealer with the lateral condensation method for canal filling, group 2 was used Ketac-Endo with the single cone method and group 3 was used Ketac-Endo with the lateral condensation method. The control group was obturated with the single cone method without sealer. The teeth were covered with two coats of nail varnish after 48 hours of obturation. The teeth were immersed in India ink for 1 week and cleaned with methyl salicylate and then the degree of dye penetration were measured with stereomicroscope. The data were analyzed statistically by one-way ANOVA. The results were as follows: 1. 7 teeth in group 1, 5 in group 2, and 3 in group 3, were showed evidence of microleakage implying appropriate canal filling. 2, The mean average of microleakage was $0.17{\pm}0.32mm$ in group 1, $0.30{\pm}0.37mm$ in group 2. $0.10{\pm}0.21mm$ in group 3, showing that canal filling using the lateral condensation canal filling method with Ketac-Endo showed the least microleakage and using the single cone method with Ketac-Endo showed the largest amount of microleakage, 3. There were no statistically significant difference in the variation of microleakage among groups. From the results above, Ketac-Endo which has the advantage of glass ionomer, whether using the single cone method or the lateral condensation method, showed similar results as AH-26, but for clinical application it is thought that were studies on the properties of Ketac-Endo should be followed.

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Studies on Isoindoline Derivatives. III. Studies on the Anhydrides and Imides of Dibasic Acids for the Organic Acids in the Gabriel Condensation (Isoindoline 유도체의 합성연구 III 이염기산무수물 또는 Imjde에 대한 유기산의 Gabriel 축합반응에 관한 연구)

  • 이남순;임중기;조태순;원정희;문도원;박인석;김무곤;민윤식;정진수
    • YAKHAK HOEJI
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    • v.18 no.1
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    • pp.59-73
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    • 1974
  • Fifteen derivatives of phthalide were synthesized from m-hemipinic, hydrastic and 4,5-benzophthalic anhydride with acetic, phenylacetic, p-methoxyphenylacetic, p-nitrophenylacetic, ${\alpha}$-nephthylacetic and succinic acid by the Gabriel condensation. In the same way, 13 derivatives of phthalimidine and 4 derivatives of ${\alpha,\beta}$ -benzisothiazoline-1, 1-dioxide were synthesized from diphenylmaleimide, phthalimide, saccharine and 4,5-benzo-phthalimide with previous 6 acids. 3-Substituted derivatives of m-hemipinic anhydride, hydrastic anhydride and 4,5-benzophthalic anhydride were treated with formamide and seven 3-substituted imidines could be synthesized. In case of 4,5-benzophtha lide, two isomers,4,5-benzophthalidene-3-acetic acid and 4,5-benzophthalidene-1-acetic acid, can be obtained theoretically, but only one product we got, and the chemical structure of it was identified by the following way. It was hydrolyzed and then decarboxylated, and this decomposed product was identical with 1-acetyl-2-naphthoic acid which was synthesized from .betha.-naphthylamine. This indicates that by the Gabriel condensatioin 4,5-benzophthalide only produces 4,5-benzophthlidene-3-acetic acid, that is ${\alpha}$-carbonyl substitute.

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