• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1998.10a
• /
• pp.3-8
• /
• 1998

The industrial revolution in England was based on the manufacturing systems by the power of water mill and rapidly progressed by the innovation of steam engine. It is no exaggeration to say that today's civilization is realized by the development of various types of power machinery, namely fluid machinery and heat engine. The electric energy is converted mainly from thermal energy (mainly steam) of mineral oil, coal and nuclear fuel through generator connected with steam turbine which is a kind of power machinery. There are various types of power machinery as shown in Tables 1a and 1b. They are classified into two types by use. One is absorption type of fluid and/or thermal energy, for examples, windmill and heat engine. The other is provision type of the energies for examples, pump, compressor and propulsion. By flow type, they are also classified by two types, turbo type and positive-displacement type. The turbo type began from water mill and windmill and evolve to steam turbine and finally to gas turbine. The positive-displacement type started from reciprocating water pump and developed into steam engine and changed to reciprocating combustion engine. The pumps and motors used in oil hydraulic system for power control are also positive-displacement type.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.9 no.2
• /
• pp.60-65
• /
• 2010

Injection molding process is one of the popular manufacturing methods to produce plastic parts with high efficiency and low cost. The tub-drum for drum type washer is made by an insert injection molding process with aluminum alloy insert of windmill type and has a big and complex structure consisted of many ribs to sustain the strength. In this paper, the volumetric shrinkages of rib part and bottom part surrounded by a windmill type insert are analyzed according to the vertical and circumferential direction of tub-drum. Volumetric shrinkage and its difference according to the height or radius of tub drum inform the designer to reduce the warpage of tub drum, and the optimal design of tub drum can be done from the those results. The change of volumetric shrinkage according to packing pressure is also analyzed. It is very important to analyze the volumetric shrinkage of tub drum because it generates the wearing phenomena at the rotating part connected to an aluminum alloy insert due to the warpage of tub drum.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.5 no.4
• /
• pp.13-20
• /
• 2006

The inherent problem of a Darrieus wind turbine is its inability to self-start. Usually, a motor is used to provide angular acceleration until lift forces are produced in the airfoil blades or up until the turbine can already sustain its speed on its own. This paper describes a method of improving the self-starting of an H-type Darrieus vertical axis wind turbine (VAWT) by incorporating a helical Savonius turbine thus utilizing a drag-lift combination. The effect of each turbine in the combination relative to each other is investigated by testing a prototype windmill consisting of three NACA 0015 airfoil blades combined with a Savonius rotor with a helix angle of 180 degrees and whose swept area equals 30% of the entire turbine.

• Korean Journal of Optics and Photonics
• /
• v.10 no.1
• /
• pp.5-9
• /
• 1999

We demonstrate a windmill type rotation of combined Mie particles caused by the evanescent field generated at the surface of a Gadolinium Gallium Garnet prism where a linearly polarized Nd:YAG laser beam (of wavelength 532 nm and power 100 mW) is totally reflected. The combined particles (e.g., doublets, triplets or quadruplets) consisting of polystyrene latex (or yeast) spheres with diameters of 3~5 m are reported to rotate at 0.1~1 rpm in water when the particles are slightly displaced from the center of the evanescent field.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.16 no.6
• /
• pp.484-489
• /
• 2003

In this paper, a single phase driven piezoelectric motor design was presented for linear motion Two metal/ceramic composite actuators, a piezoelectric ring which was bonded to a metal endcap from one side, were used as the active elements of this motor. The motor was composed of a piezoelectric ceramic, a metal ring which has 4 arms, and a guider. Motors with 30 [mm] and 35 [mm] diameter were studied by finite element analysis and experiments. As results, the maximum speed of motor was obtained at resonance frequency. When the applied voltage of the motor increased, the speed was increased. Also, bidirectional motion of the motor was achieved by combining two motors which have different resonance frequency. But the characteristics of bidirectional motion were not equaled, because of the problem of reproduction on the fabrication and the experiment. If present motor is used at the auto-zoom device of a camera, it will have much advantage. Because the direct linear motion can be achieved with a simple structure of motor and no gearbox of total system.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.3131-3135
• /
• 2008

This paper presents an energy harvester using piezoelectric elements that is a kind of generator which converts the mechanical power to the electric one using windmill system with many PZT actuators. In this study, low frequency characteristics of the cantilever-type piezoelectric actuator are experimentally investigated. Advantages of the cantilever use are to take a very large displacement and to improve the endurance of the PZT element. The material of cantilever is an aluminum and three kinds of cantilever of which size is $150[mm]{\times}20[mm]{\times}1.5[mm]$, $170[mm]{\times}20[mm]{\times}1.5[mm]$ and $190[mm]{\times}20[mm]{\times}1.5[mm]$ were experimented, respectively. The cantilever was fixed on the vibrator. The characteristics of frequency and mass variation of cantilever end part such as 0[g], 5[g], 10[g] are investigated. Maximum voltage was outputted at the condition of $150[mm]{\times}20[mm]{\times}1.5[mm]$ and 10[g] of mass. It was confirmed that the lower natural frequency at the larger length of cantilever and at the bigger of mass is gotten.

• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.2
• /
• pp.129-138
• /
• 2012

In this study, three types of large scale multi-tasking machine tools together with core technologies involved have been developed and introduced; a multi-tasking machine tool for large scale marine engine crankshafts, a multi-tasking vertical lathe for windmill parts, and a large scale 5-axis machine tool of gantry type. Several special purpose devices has been necessarily developed for the purpose of handling and machining big and heavy workpieces accurately, such as PTD (Pin Turning Device) with revolving ring spindle for machining eccentric crankshaft pins, hydrostatic rotary table and steady rest for supporting and resting heavy workpieces, and 2-axis automatic swiveling head for high-quality free surface machining. Core technologies have been also developed and adopted on their detail design stage; 1) structural design optimization with FEM structural analysis, 2) theoretical hydrostatic analysis for the PTD and rotary table bearings, 3) box-in-box type cross-rail and octagonal ram design to secure machine rigidity and accuracy, 4) constant spindle rpm control against gravitational torque due to unbalanced workpiece.

• Journal of Korean Physical Therapy Science
• /
• v.18 no.3
• /
• pp.1-7
• /
• 2011

Background : Respiratory muscle weakness has serious clinical consequences. Vital Capacity is the volume of air that is normally exchanged in a single breath. It varies widely with pulmonary health and overall fitness. Purpose : The purpose of this study was to investigate the variation of vital capacity(VC) according to the effects of Kinesio taping and balloons blowing. Methods : Twenty-one non-smokers were participated in this research and these subjects were randomly assigned into three groups; a balloons blowing group(n=7), a Kinesio taping group(n=7), and a balloons blowing and Kinesio taping group(n=7). This experiment was done from June 22, 2009 to July 5, 2009. In order to measure the VC variation effects of Kinesio taping, balloons blowing, and both intervention, an windmill type spiropet was used. The collected data were analyzed statistically by using a paired t-test and ANCOVA. Results : The results of this study were as follows; 1) In the case of balloons blowing, there was a significant difference, 3.35% increase of VC, between before and after 2 weeks experiments(p<.01). 2) In the case of Kinesio taping, there was a significant difference, 11.66% increase of VC, between before and after 2 weeks taping intervention(p<01). 3) In the case of both balloon blowing and Kinesio taping, there was a significant difference, 15.84% increase of VC, between before and after 2 weeks both interventions(p<.01). 4) After 2 weeks experiment, the improvement of VC was shown a significant difference with intergroup(p<.05). Conclusion : From these results, it was revealed that balloons blowing or Kinesio taping, or both interventions were effective to improve VC of healthy adults.