• Food Science and Biotechnology
• /
• v.17 no.4
• /
• pp.846-849
• /
• 2008

This study employed high performance liquid chromatography (HPLC) coupled to an on-line $ABTS^+$ radical scavenging detection (RSD) system along with HPLC-electro spin impact/mass spectrometry (ESI/MS), to rapidly determine and identify antioxidant compounds occurring in blueberry extract. The extract was separated by HPLC, and then the radical scavenging activities of the separated compounds were evaluated by the on-line coupled $ABTS^+$-RSD system. The negative peaks of the $ABTS^+$-RSD system, which indicates the presence of antioxidant activity, were monitored by measuring the decrease in absorbance at 734 nm. The active components in the blueberry extract were identified by HPLC-ESI/MS using their MS spectra and retention times. According to the data acquired from the on-line HPLC-$ABTS^+$-based assay and HPLC-ESI/MS systems, the antioxidant compounds detected in the blueberry extract were identified as chlorogenic acid and 11 anthocyanins.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.7 s.184
• /
• pp.177-186
• /
• 2006

In order to realize a three-dimensional shape on CAD, the machining process has been widely used because it offers practical advantages such as precision and versatility. However, the traditional machining process needs a large amount of time in cutting a product and the remained material causes trouble such as inconvenience due to cleaning process. Therefore, a new rapid manufacturing process, Rapid Heat Ablation process (RHA) using the hot tool, has been developed. In this paper, the hot tool for RHA process is designed to minimize radius of heat affected zone. TRIZ well-known as creative problem solving method is applied to overcome the contradictive requirements of the hot tool. For the detailed design of the hot tool, numerical model is established with several assumptions. In order to verify the numerical results, surface temperature of the hot tool is measured with K-type thermocouple at the predetermined location. Numerical and experimental results show that the devised hot tool fulfils its requirements. The practicality and effectiveness of the designed hot tool have been verified through experiments.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.6 s.171
• /
• pp.222-231
• /
• 2005

Recently, life cycle and lead-time of products have been shortened with the demand of customers. Therefore, it is important to reduce time and cost at the stage of manufacturing trial molds. In order to realize a three-dimensional shape on CAD, the machining process has been widely used because it offers practical advantages such as precision and versatility. However, the traditional machining process needs a large amount of time in cutting a product and the remained material causes trouble such as inconvenience for clarity. In this work, a new rapid manufacturing process using the hot tool, Rapid Heat Ablation process, has been developed to overcome such limitations. While the hot tool moves the predetermined path, the heat of the tool decomposes the remained material. The radius of heat affect ed zone related to process parameters was investigated through experiments to improve the quality of ablated parts. In order to examine the applicability of the proposed process, three-dimensional shapes such as hemisphere and standard test part, wereablatedutilizingtheapparatus.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.224-230
• /
• 2005

In order to realize a three-dimensional shape on CAD, the machining process has been widely used because it offers practical advantages such as precision and versatility. However, the traditional machining process needs a large amount of time in cutting a product and the remained material causes trouble such as inconvenience due to cleaning process. This paper introduces a new rapid manufacturing process called Rapid Heat Ablation process (RHA) using the rotary hot tool to overcome limitations of traditional machining process. The rotary hot tool to satisfy requirements of RHA process is designed and produced. In order to examine relationships between kerfwidth and process parameters such as heat input, speed of tool and speed of revolution, experiments were carried out. In addition, relationship between the kerfwidth and the effective heat input was obtained. Based on the experimental results, double-curved shape was ablated to show the validity of proposed process. In the procedure, the rough cut and fine cut were performed according to the conditions of process parameters without tool change process. The practicality and effectiveness of the proposed process have been verified through ablation of three-dimensional shape.

• Structural Engineering and Mechanics
• /
• v.73 no.4
• /
• pp.427-436
• /
• 2020

The use of final IGS precise orbit and clock products for high-rate GNSS-PPP proved its effectiveness in capturing dynamic displacement of engineering structures caused by earthquakes. However, the main drawback of using the final products is that they are available after approximately two weeks of data collection, which is not suitable for timely measures after an event. In this study, the use of ultra-rapid products (observed part), which are available after a few hours of data collection, and rapid products, which are available in less than 24 hrs, are investigated and their results are compared to the more precise final products. The tests are designed such that harmonic oscillations with different frequencies and amplitudes and ground motion of a simulated real earthquake are generated using a single axis shake table and the PPP was used to capture these movements by monitoring time-change of the table positions. To evaluate the accuracy of PPP using ultra-rapid, rapid and final products, their results were compared with relative GNSS positioning and LVDT (Linear Variable Differential Transformer) data, treated as reference. The results show that the high-rate GNSS-PPP solutions based on the three products can capture frequencies of harmonic oscillations and dynamic displacement with good accuracy. There were slight differences between ultra-rapid, rapid and final products, where some of the tested events indicated that the latter two produced are more accurate and provide better results compared to the ultra-rapid product for monitoring short-term dynamic displacements.

• Journal of Power System Engineering
• /
• v.13 no.4
• /
• pp.38-42
• /
• 2009

The Injection molding is used more than 70% of total production in plastic products. The injection molding process has 4 processes such as filling, packing, cooling and ejecting. now then, cooling process spends the most of times in Injection molding cycle time. Therefore, it is important to control the mold temperature in producing plastic products. The cooling system and time affect the product's quality and productivity. Especially, cooling time has about 60% of total injection cycle time. Therefore, we can improve a productivity by shortening cooling time. In this study, the rapid cooling system was developed and performed a efficiency test. This system could refrigerate coolant to $1^{\circ}C$ and had to need 10 minutes for normal operating.

• Transactions of Materials Processing
• /
• v.16 no.7
• /
• pp.549-554
• /
• 2007

The objective of this paper is to investigate into the fabrication technology of cores for the injection mould with three-dimensional conformal cooling channels to reduce the cooling time. The location of the conformal cooling channels has been determined through the injection molding analysis. The mould has been manufactured from a hybrid rapid tooling technology, which is combined a direct metal rapid tooling with a machining process. Several injection molding experiments have been performed to examine the productivity and the validity of the designed mould. From the results of the experiments, it has been shown that the proposed mould can mold a final product within a cooling time of 3 seconds and a cycle time of 21 seconds, respectively.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.9 no.1
• /
• pp.30-37
• /
• 2000

In this paper rapid prototyping and precision casting technology have been developed for the manufacturing of inlet gear box of an airplane, Rapid prototyping is a new prototyping technology that produces complicated parts directly from three-dimensional CAD data with a high efficiency and has been extensively applied to various manufacturing processes. In the present work Selective Lase Sintering(SLS) system is utilized in order to manufacture prototype of the inlet gear box. Prototyping technology using SLS is also investigated from the viewpoint of accuracy. Using the SLS master the casting products are manufactured through several processes such as : vacuum casting lost wax shell casting and investment cast-ing. The shrinkage characteristics of wax and cast iron in the casting procedures are considered and then reflected to the design procedure so that the accuracy of the product is improved consequently.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.3 no.4
• /
• pp.303-307
• /
• 2002

A new product development procedure that uses a rapid prototyping and 3D CAD has been suggested. By applying this procedure to the development of an aroma diffuser, considerable amount of development time and cost were reduced. Moreover, by using 3D CAD from the early design stage, the number of trial and error can be reduced.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.483-486
• /
• 2001

Rapid Prototyping(RP) has been widely applied in designing and developing processes a new product. The functional requirements of a rapid prototyping system are high speed and high accuracy, and they depend on the operating parameters, some of which can be set by users. The accuracy is evaluated by dimensional errors and form errors of manufactured pars. A specially designed specimen with various features has been used for the accuracy evaluation. According to the Taguchi experimental design techniques, and orthogonal array of experiments has been set which has the least number of experimental runs to find the parametric effects. A laser scanner is used to obtain the point data of the parts and Surfacer is used to determine the lengths and angles. The conditions for the FDM manufacturing parametrs have been found.