• Journal of Dental Rehabilitation and Applied Science
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• v.20 no.1
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• pp.43-50
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• 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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.21-27
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• 2018

FRN (Full range Naphtha) is distilled from crude oil in a Naphtha Splitter Unit and is separated into the Light Straight Naphtha, Heavy Naphtha, and kerosene according to the boiling point in sequence. This separation is conducted using a series of binary-like columns. In this separation method, the energy consumed in the reboiler is used to separate the heaviest components and most of this energy is discarded as vapor condensation in the overhead cooler. In this study, the first two columns of the separation process are replaced with the Petlyuk column. A structural design was exercised by a stage to stage computation with an ideal tray efficiency in the equilibrium condition. Compared to the performance of a conventional system of 3-column model, the design outcome indicates that the procedure is simple and efficient because the composition of the liquid component in the column tray was designed to be similar to the equilibrium distillation curve. An analysis of the performance of the new process indicated an energy saving of 12.3% under same total number of trays and with a saving of the initial investment cost.

• Journal of Microbiology and Biotechnology
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• v.25 no.6
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• pp.803-813
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• 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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.607-614
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• 2016

In generating station, cable spreading design is a very important task, which is very much time consuming, due to the type of cable used in generating station is very diverse. The raceway means the cable line section from source equipment to destination, and consists of cable tray and conduit. The process of existing cable spreading design was written in by hand. Thereby, there are grossly inefficient gain such as cable omission and unfixed fill value by a personal and time investment. In this paper, we proposed and implemented the automated cable route design based flexible cable fill check in generating station, and proposed the automated cable route design can be calculated the cable fill with flexible changing of raceway. Some experimental result shows that implemented cable route design is well performed and conducted as the design specifications, and it will be able to reduce the cable spreading design time.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.4
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• pp.477-487
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• 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.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.2
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• pp.60-67
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• 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.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.3
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• pp.389-400
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• 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
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• v.41 no.4
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• pp.342-356
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• 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.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.11 no.1
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• pp.17-24
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• 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.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.4
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• pp.508-514
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• 2021

In this report, Replicated denture was fabricated by 3d printing after scanning the existing denture. It was used as an individual tray in closed-mouth technique. It reduced laboratory process and clinical time. Also it helped in facial evaluation and tooth arrangement. Compared to open-mouth technique, the number of visits was reduced, and the patient's adaptability to new denture was enhanced by utilized various information of the existing denture, including vertical dimension.