• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.1040-1047
• /
• 2008

Hypoid gears are widely used in rear drive and 4WD vehicle axles. Investigation of their sensitivity to deflections is one of the most important aspects of their design and optimization procedures. The deflection test is performed in the actual gear mounting using completely processed gear. This test should cover the full operating range of gear loads from no load to peak load. Under peak load the contact pattern should extend to the tooth boundaries without showing a concentration of the contact pattern at any point on the tooth surface. Transmission error is tested on an axle assembly triaxial real car load condition.

• Proceedings of the KIEE Conference
• /
• 2003.11b
• /
• pp.307-310
• /
• 2003

In this paper, an iterative learning control method is applied to suppress the vibration of a 2-mass system which has a flexible coupling between a load an a motor. More specifically, conditions for the load speed without vibration are derived based on the steady-state condition. And the desired motor position trajectory is synthesized based on the relation between the load and motor speed. Finally, a PD-type learning iterative control law is applied for the desired motor position trajectory. Since the learning law applied for the desired trajectory guarantees the perfect tracking performance, the resulting load speed shows no vibration. In order to handle the initial position error, the PD-type learning law is changed to PID-type and a weight function is added to suppress the residual vibration caused by the initial error. The simulation results show the effectiveness of the proposed learning method.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.44 no.2
• /
• pp.127-135
• /
• 2002

Due to the fact that the design of a reinforced concrete structure changes in accordance with its shape and assigned load, total automation of the design system has not been achieved. For instance, since there is no general rule about setting up reinforcing steel quantity and arrangement location, it is simply not feasible to automatically decide the reinforcing arrangement location. In this study, the ESO(evolutionary structural optimization) technique and its related issues will be discussed. The ESO techniques is determined the reasonable load path which is traveling of load between in-flow and out-flow at a concrete structure using numerical analysis. And the results applied to the steel arrangement in reinforced concrete structures. The optimal algorithm, which determines the terminal criteria during ESO process, has been updated by using the obtained results. And the load path within the member has been determined automatically.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.19 no.2
• /
• pp.127-137
• /
• 2009

Hypoid gears are widely used in rear drive and 4WD vehicle axles. Investigation of their sensitivity to deflections is one of the most important aspects of their design and optimization procedures. The deflection test is performed in the actual gear mounting using completely processed gear. This test should cover the full operating range of gear loads from no load to peak load. Under peak load the contact pattern should extend to the tooth boundaries without showing a concentration of the contact pattern at any point on the tooth surface. Transmission error is tested on an axle assembly triaxial real car load condition.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.7 no.5
• /
• pp.316-322
• /
• 2002

A newly isolated heterotrophic marine bacterium, Vibrio alginolyticus, was used to remove a high load of ammonia gas under non-sterile condition. The cells were inoculated onto an inorganic packing material in a fixed-bed reactor (biofilter), and a high load of ammonia, in the range of ammonia gas concentration of 170 ppm to 880 ppm, was introduced continuously. Sucrose solution and 3% NaCl was supplied intermittently to supplement the carbon source and water to the biofilter. The average percentage of gas removed exceeded 85% for 107-day operation. The maximum removal capacity and the complete removal capacity were$19\;g-N\;kg^{-1}$ dry packing material $day^{-1}$ and $16\;g-N\;kg^{-1}$ dry packing material $day^{-1}$, respectively, which were about three times greater than those obtained in nitrifying sludge inoculated onto the same packing material. On day 82, the enhanced pressure drop was restored to the normal one by NaOH treatment, and efficient removal characteristics were later observed. During this operation, the non-sterile condition had no significantly adverse effect on the removability of ammonia by V. alginolyticus.

• Korean Journal of Applied Biomechanics
• /
• v.16 no.2
• /
• pp.37-44
• /
• 2006

The purposes of this study were to analyze and compare EMG activities of the pectoralis major, biceps brachii, triceps brachii, and brachioradialis muscles during biceps curls using a VRT device and an elastic tubing. Fifteen male college students were recruited as subjects and they performed 10-RM and 20-RM biceps curls. For each load and device condition, the mean and peak normalized EMG levels during different phases of a biceps curl were computed. For each load and phase, paired t-test (p.05) was used to find the significant difference between two devices. ANOVA with repeated measures was also used to find the significant difference among phases in terms of EMG values for each muscle. For each load and device condition, the peak and mean EMG levels during different phases of a biceps curl were computed The significant differences between devices were found in biceps brachii for EA, MD, LD phases, and triceps brachii muscles for all phases, respectively. However, no differences were found among phases for any muscle. This indicated that elastic band could have a similar characteristics of VRT. High antagonistic muscle activity as a function of injury prevention which found particularly in VRT device may suggest that elastic tubing can be a safer training device than VRT. This also imply that elastic tubing could be very effective as a home exercise tool for rehabilitation patients and elderly people.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.149-152
• /
• 2006

Serviceability of reinforced concrete building is affected dominantly by long term deflection of slab. And in case of reinforced concrete building with flat plate slab, severe long term deflection was expected because it has no beams which have large flexural stiffness. Therefore it is important to calculate exactly long term deflection of RC flat plate structure to assure its serviceability. However, current codes couldn't calculate exactly long term deflection of RC flat plate structure because they don't consider effects of boundary condition and construction load. By the way, recently the method to calculate long term deflection of RC flat plate structure was proposed by considering these effects. In the present study, long term deflection of RC flat plate structure was analyzed by comparing this method with recent experimental results. In conclusion, long term deflection of RC flat plate structure was affected considerably by effects of boundary condition, construction load and tensile strength of concrete. And recently proposed method considers these effects reasonably but it should be modified to reflect creep effect of RC flat plate slab reasonably.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.754-755
• /
• 2008

This paper presents a method for reducing the Total Harmonic Distortion(THD) of line-line back_EMF of the IPMSM with distributed winding under the no-load condition. Firstly, the specific harmonic components of line-line back EMF are reduced considering with winding factor. Secondly, THD of line-line back EMF is minimized according to change of pole angle using by Space harmonic Analysis. Finally, the optimal design for minimizing the THD is conducted using response surface methodology with finite element analysis. The validity of the design method dealt with in this paper is demonstrated by comparison between the THD of optimal model and initial model.

• The KSFM Journal of Fluid Machinery
• /
• v.18 no.6
• /
• pp.12-18
• /
• 2015

Recently, the development trend of turbomachinery is high capacity and high efficiency. Most of turbomachinery in the market are adopting ball bearings or air foil bearings. However, ball bearings have a limit for high speed product over $2.0{\times}10^6DN$(product of the inner diameter of the bearing in mm (D) and the maximum speed in rpm (N)). Air foil bearings have a limit for high axial load for high power products over 200~300 HP(horse power). Magnetic bearing is one of the solutions to overcome the limits of high speed and high axial load. Because magnetic bearings have no friction between the rotor and the bearings, they can reduce the load of the motor and make it possible to increase the rotating speed up to $5.0{\times}10^6DN$. Moreover, they can have high axial load capacity, because the axial load capacity of magnetic bearing depends on the capacity of the designed electromagnet. In this study, the radial and thrust magnetic bearings are designed to be applied to the 200 HP class turbo blower, and their performance was evaluated by the experiment. Based on the tests up to 26,400 rpm and 21,000 rpm under the no-load and load condition, respectively, it was verified that the magnetic bearings are stably support the rotor of the turbo blower.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.51 no.5
• /
• pp.69-78
• /
• 2009

In order to improve water quality of upper watershed of Paldang reservoir, it is necessary to evaluate non-point source pollution loads and identify critical watershed pollution sources. A GIS based Soil and Water Assessment Tool was applied to evaluate model application and reliability, estimate NPS pollution load, identify critical watershed by NPS pollution sources, and suggest various best management practices for Kyongan Stream watershed. Yearly NPS pollution loads were estimated 30.0% SS, 60.1% TN and 35.4% TP, respectably. The watershed pollution load is mainly decided by precipitation condition and SS and nutrients load have a significant regression relationship. Based on 10-year average yearly NPS pollution load, critical sub-watersheds were identified. The No. 5 and 17 which have lots of relatively intensive agricultural fields and scattered industrial area were vary critical sub-watersheds and under more intensive pollution load. In order to control critical watershed, watershed best management practices such as scientific fertilizer, contour farming and parallel terrace, transferring the sloppy farmland to grass or forest and constructing a buffer zone, and constructing wetlands and retention ponds will be applied. Overall the SWAT model can be efficiently used for identification of critical sub-watersheds in order to develop a priority watershed management plan to reduce water pollutions.