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Chun D.-H.,Yeungnam University | Lim B.-D.,Yeungnam University | Kim D.-K.,Korea Textile Machinery Research Institute
39th International Congress on Noise Control Engineering 2010, INTER-NOISE 2010 | Year: 2010

Considering the corresponding reverberation time at each measuring point on determination of sound power levels of noise source using sound pressure in a non-uniform reverberation space, the accuracy is improved. The previous researched method is required the distance to measured point from source. In general, the exact position of source is unknown. This study considers the effect of position error in the previous method, and suggests that an approximation of the representative source position is a center of the measuring box from ray-tracing simulation and experiments.

Kim K.-S.,Andong National University | Lee K.-A.,Andong National University | Kim J.-H.,PIM Korea Co. | Park S.-W.,Korea Textile Machinery Research Institute | Cho K.-S.,Dongyang University
Advanced Materials Research | Year: 2013

Inconel 713C alloy was tried to manufacture by using MIM(Metal Injection Molding) process. The high-temperature mechanical properties of MIMed Inconel 713C were also investigated. Processing defects such as pores and binders could be observed near the surface. Tensile tests were conducted from room temperature to 900°C. The result of tensile tests showed that this alloy had similar or somewhat higher strengths (YS: 734 MPa, UTS: 968 MPa, elongation: 7.16% at room temperature) from RT to 700°C than those of conventional Inconel 713C alloys. Above 800°C, however, ultimate tensile strength decreased rapidly with increasing temperature (lower than casted Inconel 713C). Based on the observation of fractography, initial crack was found to have started near the surface defects and propagated rapidly. The superior mechanical properties of MIMed Inconel 713C could be obtained by optimizing the MIM process parameters.© (2013) Trans Tech Publications, Switzerland.

Kim H.K.,Korea Textile Machinery Research Institute | Chun D.H.,Yeungnam University | Kim J.H.,Yeungnam University
Fibers and Polymers | Year: 2013

In connection with an effect on development of dynamic model of beat-up process, beat-up force and weaving condition, this study has investigated a correlation of 4 kinds of weaving factors (warp tension, weft thickness, weft density and shedding height) that affect beat-up force through an experimental method and analytic method. A simulator was developed to imitate beating, shedding, and insertion motions for weaving and the experiment was performed using the simulator. The experiments showed following results: First, the beat-up force increased proportionally as the warp tension increased. Second, the beat-up force increased with the increase of the weft thickness. Third, the beat-up force was exponentially inversely proportional to the weft density. Finally, the beat-up force was increased with the increase of the shedding height. Various experimental and simulation methods were performed to investigate the contribution of the principal weaving parameters to the beat-up force. © 2013 The Korean Fiber Society and Springer Science+Business Media Dordrecht.

Cho K.-S.,Dongyang University | Lee K.-A.,Andong National University | Kim M.-J.,Andong National University | Jeong J.-O.,PIM KOREA Co. | Park S.-W.,Korea Textile Machinery Research Institute
International Powder Metallurgy Congress and Exhibition, Euro PM 2013 | Year: 2013

In this research, we performed tensile tests, microstructure analysis, and high-cycle fatigue tests of Fe-2%Ni alloy specimen produced by using the metal injection molding (MIM) process. In the microstructure observation results, inhomogeneous ferrite and pearlite were appeared. As a result of tensile tests, the tensile strength and strain rate of the specimen was 605 MPa and approximately 6.0%, respectively, and the hardness of the specimen was approximately 220 Hv. The high-cycle fatigue tests revealed the fatigue limit of the Fe-2%Ni alloy specimen to be 410 MPa. Further, by analyzing the fracture surface, we appraised the tensile and fatigue failure behavior of Fe-2%Ni alloys produced by the metal injection molding.

Chun D.H.,Korea Textile Machinery Research Institute | You B.H.,Yeungnam University | You B.H.,Texas State University | Lee H.J.,Texas State University
Fibers and Polymers | Year: 2014

Injection molding has been widely used in the manufacturing of various polymer products, including housewares, home appliances, and automotive parts. A disposable medical device based on polymeric material at a low cost is another important area for injection molding. The numerical analysis was performed to predict the potential problem, often occurring during the manufacturing process of the medical device. Computer-aided engineering model was developed using industry-standard molding software, MOLDFLOW®. The flow pattern of the molten polymer was investigated in the replication of butterfly shaped Catheter Support for various catheterization. The flow pattern and temperature distribution of the molded part were investigated through a series of analysis. The results of analysis with original design predicted non-uniform polymer flow with a poor weld line, unbalanced cavity filling, and uneven temperature distribution of the part. An appropriate gate location to achieve uniform flow pattern for mold filling was determined on the base of the predicted results and experience, considering the performance of the product and limitation of the production. © 2014 The Korean Fiber Society and Springer Science+Business Media Dordrecht.

Chun D.H.,Yeungnam University | Na H.J.,Korea Textile Machinery Research Institute
19th International Congress on Sound and Vibration 2012, ICSV 2012 | Year: 2012

Since the earliest discoveries of Sabine, the reverberation time is considered to be one of the most important factors in determining the sound quality of a room. The assumptions of homogeneous energy (completely diffuse sound in the room), and continuous, uniform absorption of energy by the boundary surfaces of the room are intrinsic to the theory. For very non-uniformly placed absorbents with same room absorption, as when just one wall is highly absorptive and the rest are reflective, the reverberation time is different. In this paper, the reverberation time by placement of absorbing materials are examined both numerically and experimentally.

Kim H.K.,Korea Textile Machinery Research Institute | Park D.K.,Korea Textile Machinery Research Institute | Chun D.H.,Yeungnam University
Fibers and Polymers | Year: 2015

The following study was focused on developing the technology for the evaluation of industrial felt when reliability test among industrial felt is critical. As such, the intentions are to secure reliability of the products, to be used actively for inspecting the reliability of new innovative products, and to help increase quality. The research placed industrial felt in an even more strenuous condition that’s different from the actual conditions they are normally used under in order to accelerate the potential for failure. Therefore, the results of the study have confirmed that an accelerated testing criteria conducted under a 30 day period was a good proxy for a year-long usage condition. Additionally, the results show that the old product’s strength is only about 50 % of the new product, which is a considerable difference. The reasons for such degradation are due to the reduction in coherence between fabrics which causes destruction in the fibrous tissue which in turn causes a reduction in strength values. Consequently, this study attempts to evaluate the performance and quality of the felt in order to establish a relationship between lifespan and performance. With this, the research deems possible that the process can be applied on the evaluation of the durability life of industrial felt products. © 2015, The Korean Fiber Society and Springer Science+Business Media Dordrecht.

Kim M.,Yeungnam University | Han M.S.,Korea Textile Machinery Research Institute | Seo T.,Yeungnam University | Lee J.,Yeungnam University
International Journal of Control, Automation and Systems | Year: 2016

Instantaneous center (IC) analysis of a mechanism is very important in mechanism analysis, since the analysis gives intuition about the global movement of the mechanism, and the analysis also makes the numerical analysis of velocities faster. Previous IC analysis methods have used geometrical information from the mechanism configuration. Such methods have disadvantages of complexity in calculation and difficulty determining the direction of linkage movement due to geometric complexity. This research suggests a new IC analysis method for planar closed chains. The proposed method determines the IC simply from the relation between joint velocities based on graphical representation. Twists in screw theory are used to define the joint velocities in a closed chain and also to calculate the IC. Three different kinds of mechanisms are analyzed by the method: a four-bar mechanism, slidercrank mechanism, and a multiple closed-chain mechanism composed of four-bar and slider-crank mechanisms. The analysis methodology can be applied to calculate the ICs of various planar closed chains. © 2016 Institute of Control, Robotics and Systems and The Korean Institute of Electrical Engineers and Springer-Verlag Berlin Heidelberg

Kim J.C.,Gwangju Institute of Science and Technology | Chung Y.-I.,Gwangju Institute of Science and Technology | Chung Y.-I.,Korea Textile Machinery Research Institute | Kim Y.H.,Gwangju Institute of Science and Technology | Tae G.,Gwangju Institute of Science and Technology
Journal of Biomedical Nanotechnology | Year: 2014

Controlling the permeability of liposome is important to modulate the release behavior of drug from the liposome. Pluronic F127 (PF127) is a biocompatible tri-block copolymer, which can interact with lipid bilayer of liposomes and make leakages that allow the release of hydrophilic substance from liposome interior. However, the interaction between unmodified PF127 and lipid bilayer is not very strong and the incorporated PF127 is easily desorbed from the liposomes in an infinite reservoir condition. In this paper, we conjugated lipid molecule (1,2-distearoyl-sn-glycero-3-phosphoethanolamine [DSPE]) at the both ends of PF127 to increase the interaction between polymer and liposome. This lipid-conjugated PF127 was incorporated into the liposomes and it remained stably without desorption from liposomes in an infinite reservoir condition. The stably bound PF127 increased the release rate of hydrophilic drug from liposomes in a dose-dependent manner. Moreover, the lipid-conjugated PF127 changed the surface property of liposomes and inhibited its cellular uptake when the incorporated amount was above 2.5 wt%. In conclusion, the lipid-conjugated PF127 could function as a stable anchor on the lipid bilayer of liposomes to control the permeability as well as provide the hydrophilic surface of liposomes in an open system like an in vivo situation. Copyright © 2014 American Scientific Publishers All rights reserved.

Lee J.Y.,Korea Textile Machinery Research Institute | Lee K.B.,Yeungnam University | Kim J.H.,Yeungnam University
Journal of Vibroengineering | Year: 2015

An automobile active accelerator pedal (AAP) warns the driver about an emergency. A tubular electromagnetic linear actuator is the key component to create an impact or vibration, but it has a large cogging force due to a steel core that causes instabilities. Accordingly, we propose an AAP with a coreless tubular electromagnetic linear actuator, and verify its performance using dynamic experiments. © JVE INTERNATIONAL LTD.

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