• 구강회복응용과학지
• /
• 제20권1호
• /
• pp.43-50
• /
• 2004

This study was performed to measure the retentive force of dental impression tray according to retention form. The 9 resin beams($30{\times}60{\times}2.5mm$) were made of visible light-curing tray resin according to the surface texture, the size of hole and the number of rim. The resin block was fabricated in width 50mm, length 30mm, heght 40mm to maintain an even hydrocolloid impression material. The retentive force between the resin beam and hydrocolloid impression material was measured by Universal Testing Machine(Zwick Z020, Zwick Co., Germany). The results obtained in this study were as follows : 1. The retentive force of the resin beam with bilateral 4 rims, 2mm holes(9group) was highest(9.18kg), and the polishing resin beam(2group) was worst(4.85kg). 2. There was no significant difference between the polished the resin beam(2group) and the contrast resin beam(1group). 3. The retentive force of the rimmed resin beam was higher than the perforated resin beam. 4. The retentive force of the 2mm perforated resin beam(4group) was higher than the 3mm perforated resin beam(3group). 5. As increasing the number of rim increased the retentive force.

• 한국산학기술학회논문지
• /
• 제19권2호
• /
• pp.21-27
• /
• 2018

나프타분리공정은 원유에서 증류 공정에 의해 얻어지는 풀레인지납사(Full Range Naphtha)를 원료로 하여 끓는점 차이에 의해 각각 경질납사, 중질납사 및 등유 반제품으로 순차적으로 분리한다. 이러한 전통적인 분리 방법은 2성분을 분리하는 Column을 연속으로 설치하여 생산한다. 이러한 분리방법은 리보일러에서 소비되는 에너지가 증류탑 내부 고비점 성분을 분리시키는 데 사용되고 이 에너지의 대부분은 탑정의 냉각기에서 응축열로 버려지게 때문에 에너지 낭비가 큰 것으로 알려져 있다 본 연구에서는 납사분리공정의 2개의 Column을 Petlyuk Column으로 설계하였다. 탑내 조성분포가 평형관계만으로 계산되는 이상적 단수 효율 하에서 stage to stage 계산방법으로 구조적 설계를 하였고 일반 증류탑과 비교한 결과 제시된 Petlyuk Distillation Column의 설계 방법이 기존의 3-column 모델법보다 설계 시간이 단축될 뿐만 아니라 증류탑내의 액의 조성분포를 평형증류 조성곡선과 유사하도록 설계함으로써 에너지 효율 측면에서도 효율적임을 입증하였다. 또한 같은 tray 단수하에서 Petlyuk Column은 일반 증류탑 대비 약 12.3% 에너지가 절약될 뿐만 아니라 초기 투자비도 절약됨을 알 수 있었다.

• Journal of Microbiology and Biotechnology
• /
• 제25권6호
• /
• pp.803-813
• /
• 2015

The growth of Irpex lacteus F17 and manganese peroxidase (MnP) production in a selfdesigned tray bioreactor, operating in solid-state conditions at a laboratory scale, were studied. The bioreactor was divided into three layers by three perforated trays. Agroindustrial residues were used both as the carrier of bound mycelia and as a nutrient medium for the growth of I. lacteus F17. The maximum biomass production in the bioreactor was detected at 60 h of fermentation, which was consistent with the CO₂ releasing rate by the fungus. During the stationary phase of fungal growth, the maximum MnP activity was observed, reaching 950 U/l at 84 h. Scanning electron microscopy images clearly showed the growth situation of mycelia on the support matrix. Furthermore, the MnP produced by I. lacteus F17 in the bioreactor was isolated and purified, and the internal peptide sequences were also identified with mass spectrometry. The optimal activity of the enzyme was detected at pH 7 and 25℃, with a long half-life time of 9 days. In addition, the MnP exhibited significant stability within a broad pH range of 4-7 and at temperature up to 55℃. Besides this, the MnP showed the ability to decolorize the polymeric model dye Poly R-478 in vitro.

• 한국정보통신학회논문지
• /
• 제20권3호
• /
• pp.607-614
• /
• 2016

발전소 설비에서 케이블 포설을 위한 설계는 발전소 설비에 사용되어지는 케이블 유형의 다양한 형태로 인해 매우 많은 시간이 요구되고 매우 중요한 과제이다. 케이블 포설 설계 시 레이스웨이(Raceway)는 출발지(Source) 장비로부터 목적지(Destination) 장비까지의 케이블 트레이(Tray) 및 콘디트(Conduit)의 포설 구간을 의미한다. 기존의 케이블 포설 설계 과정은 모두 수기에 의해 작성되어 인적/시간적 투자손실이 크고, 케이블의 누락 및 케이블 오버필(Over Fill)과 같은 비효율적인 손실이 빈번히 발생한다. 따라서 본 논문에서는 효과적인 발전소 케이블 포설 설계를 위한 레이스웨이의 유연한 케이블 오버 필(Fill) 체크 기반의 자동화된 케이블 라우팅 경로 계산 알고리즘을 구현하였고, 제안한 자동화 케이블 라우팅 설계기법은 케이블 위치의 변화에도 유연한 레이스웨이 계산이 가능하다. 구현 결과, 케이블 라우팅 설계 프로그램은 발전소 케이블 포설 설계 사양을 준수하면서 케이블 라우팅 경로를 효과적으로 설정하고, 케이블 포설 설계 시간을 기존 대비 크게 단축하는 성능을 얻을 수 있었다.

• 대한치과보철학회지
• /
• 제44권4호
• /
• pp.477-487
• /
• 2006

Purpose : this study was to evaluate the fitness of adjustable dental impression trays on the Koreans : the trays used in the previous study by Kim et al. as part of the dental adjustable tray development project were improved and modified. Material and method: The patterns of tray were made through CAD-CAM process, and a simple silicone-base molds were made from them. The trial products were reproduced by pouring polyurethane into these molds. 30 male students(Wonkwang University, Dental College) and 30 female students (Wonkwang Health Science College, Department of Dental Hygiene) were selected and Reversible hydrocolloid impression materials were used for this study. The fitness of the trays was evaluated by measuring the width and length of impression materials of each measurement sites. Results and conclusion : 1. In adapting the trays inside the mouth, a uniform width of impression material(3 $\sim$ 6mm) was obtained in most sites due to the tooth stops and the inclined planes accommodating the width of the tray 2. The thickness of impression material in the central part of the palate was a mean 9.8mm, which turned out to be somewhat thick. 3. In the mandible. the thickness of the impression material in the lingual side inferior to the contact point of the 1st and 2nd molars was 2.7mm, and the thickness of the material in the lingual side of the rearmost margin was 2.5 mm. The thickness of the impression material of these areas was relatively thin.

• 산업경영시스템학회지
• /
• 제40권2호
• /
• pp.60-67
• /
• 2017

A baggage handling system (BHS) in airport is an unified system for moving the passengers' baggage in designated time. Input baggage from the check-in counter travels to the baggage claim area or cargo handling terminal through this system. In particular, entryway BHS consists of conveyors, X-ray and sorters such as tilt-tray to send the baggage to departing airplane and it could have various problems for handling certain amount of baggage in restricted time such as baggage jamming at certain merge point. This causes systemic error such as delay of the time, omissions of the baggage and even breakdown of the equipment and inefficiency. Also the increasing maximum time of the baggage passing through the BHS could delay the flight schedule and finally decrease the service level. Thus, the algorithm for controlling the flow of the merge is essential to the system. The window reservation algorithm is the one of the most frequently used methods to control the merge configuration. Above all, the reserve location, so called reserve ahead point, that allocates the window is important for the performance of the algorithm. We propose the modified window reservation algorithm and the best reserve locations by changing the reserve ahead point in the induction conveyors. The effect of various reserve ahead points such as the capacity and utility of the system were analyzed and the most effective reserve ahead point combination was found. The total baggage processing time and the utilization of the tilt-tray are properly considered when choosing the optimal Reserve ahead point combination. In the layout of this study, the configuration of four conveyors merged into one tilt-tray is studied and simulation analysis is done by AutoMod(R), 3D simulation software. Through the simulation, the window reservation algorithm is effectively operated with the best combination of reserve ahead point which reduces the maximum baggage travel time.

• 대한치과보철학회지
• /
• 제45권3호
• /
• pp.389-400
• /
• 2007

Statement of problem. Use of the conventional dental impression procedure is problematic in patients who have difficulty opening their mouth, difficulty breathing through their nose or tendency to gag. Purpose. It is necessary to make individual trays more comfortable for patients during impression taking procedure. It was reported at the KAP Annual Meeting 2001 Seoul that an improved impression technique was suitable for this purpose. In this study, the accuracy of the improved dental impression method for implant was compared with the conventional dental impression method. Material and methods. An oral simulator was made from clear acrylic resin block which had similar form of edentulous ridge. For setting up the standard, five fixtures were installed on it. Study casts were made using two kinds of impression techniques. One was the conventional method that was taken using silicone impression material and an individual resin tray under connection of inter-fixture relation. The other was the improved method in which was the connection of the impression coping and the thermoformed polymethyl methacrylate tray. In addition, two different study casts were made from the improved impression body. The coordinates of the fixture on the study model were measured by three-dimensional coordinate measuring equipment. Then the distances between each fixture were calculated and compared with that of oral simulator. Accuracy of the each impression method was also assessed. Results. The differences of inter-fixture dimension between study casts and simulator in the improved impression technique showed $0.014{\pm}0.016mm$ and $0.017{\pm}0.022mm$, respectively and that of the conventional method was $0.017{\pm}0.014mm$. There was no significant difference between the improved impression technique and conventional method. Conclusion. The improved impression technique is useful for multiple support implants.

• Journal of Biosystems Engineering
• /
• 제41권4호
• /
• pp.342-356
• /
• 2016

Purpose: The drying of a thin layer of native cassava starch in a tray dryer was modeled to establish an equation for predicting the drying behavior under given conditions. Methods: Drying tests were performed using samples of native cassava starch over a temperature range of $40-60^{\circ}C$. We investigated the variation in the drying time, dynamic equilibrium moisture content, drying rate period, critical moisture content, and effective diffusivity of the starch with temperature. The starch diffusion coefficient and drying activation energy were determined. A modification of the model developed by Hii et al. was devised and tested alongside fourteen other models. Results: For starch with an initial moisture content of 82% (db), the drying time and dynamic equilibrium moisture content decreased as the temperature increased. The constant drying rate phase preceded the falling rate phase between $40-55^{\circ}C$. Drying at $60^{\circ}C$ occurred only in the falling rate phase. The critical moisture content was observed in the $40-55^{\circ}C$ range and increased with the temperature. The effective diffusivity of the starch increased as the drying temperature increased from 40 to $60^{\circ}C$. The modified Hii et al. model produced randomized residual plots, the highest $R^2$, and the lowest standard error of estimates. Conclusions: Drying time decreased linearly with an increase in the temperature, while the decrease in the moisture content was linear between $40-55^{\circ}C$. The constant drying rate phase occurred without any period of induction over a temperature range of $40-55^{\circ}C$ prior to the falling rate period, while drying at $60^{\circ}C$ took place only in the falling rate phase. The effective diffusivity had an Arrhenius relationship with the temperature. The modified Hii et al. model proved to be optimum for predicting the drying behavior of the starch in the tray dryer.

• 한국포장학회지
• /
• 제11권1호
• /
• pp.17-24
• /
• 2005

During handling unitized products, they are subjected to a variety environmental hazards. Shock and vibration hazards are generally considered the most damaging of the environmental hazards on a product, and it may encounter while passing through the distribution environment. A major cause of shock damage to products is drops during manual handling. The increasing use of unitization on pallets has been resulted in a reduction in the manual handling of products and with it a reduction in the shock hazards. This has caused and increasing interest in research focused on vibration caused damage. the use of pallets as a base for unitizing loads, aids in the mechanical handling, transportation and storage of products. Besides aiding in the handling, transportation and storage of products, a pallet also acts on and interface between the packaged goods and the distribution environment. The determination of the impact deformation of the cushioning materials such as tray cup (polymeric foam) and corrugated fiberboard pad must be carried out to design the proper packaging system providing adequate protection for the fruit, and to understand the complex interaction between the components of fruit when they relate to expected transportation vibration inputs. In this study, the theoretical analysis of impact deformation for cushioning materials by dynamic vibration. The impact deformations of SW and DW corrugated fiberboard pad in acceleration amplitudes of 0.25 G-rms and 0.5 G-rms that were usually generated in transport vehicles during distribution environments were very small compare with the thickness of corrugated fiberboard pad. The maximum of vibration acceleration level of tray cup by vibration impact was about 3.2 G-rms. The theoretical allowable acceleration (G-factor) of the pear was 0.7102 G-rms, and the maximum dynamic deformation estimated within G-factor was about 1 mm.

• 대한치과보철학회지
• /
• 제59권4호
• /
• pp.508-514
• /
• 2021

본 증례는 기존 의치를 스캔 후 프린팅한 복제 의치를 폐구인상시 개인트레이로 사용하였고 이에 기공 과정을 줄이고, 진료시간을 단축시킬 수 있었으며, 안모 평가가 용이하고 치아 배열을 비롯한 총의치 제작과정에 있어 기공 과정이 원활하게 이뤄질 수 있었다. 또한 일반적인 개구인상법을 이용한 제작과정에 비해 내원 횟수를 줄일 수 있었으며 기존 의치의 수직고경을 비롯한 여러 정보를 의치 제작 시 활용함으로써 환자의 새 의치 적응도를 높일 수 있었다.