• Membrane and Water Treatment
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• 제9권1호
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• pp.33-42
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• 2018

Microscopic examination of the activated sludge and morphological characterization of the flocs provides detailed information about the treatment process. The aim of this study is to investigate the morphological parameters of flocs obtained from a thermophilic jet loop membrane bioreactor (JLMBR) in different sludge retention times (SRTs), considering EPS and SMP concentration, hydrophobicity, zeta potential. The results showed that irregularity decreased with the increasing SRT. The compactness value was calculated to be less than 1 for all SRTs. However, the sludge had a more compact structure when the SRT increased. Zeta potential increased whereas hydrophobicity and floc size reduced, with increasing SRT. Furthermore, 2-D porosity calculated using the hole ratio was higher at greater SRTs. Hence, there was a significant correlation between the results obtained using the imaging technique and operation conditions of thermophilic JLMBR.

• Journal of Biosystems Engineering
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• 제26권6호
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• pp.495-502
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• 2001

Upright positioning of garlic cloves has been considered as an essential process for mechanical planting because positioning affects the quality and yield of garlic production. Due to the geometrical uniqueness and irregularity of garlic cloves in shape, the planting operation has been conducted by manual. Manual planting requires intensive labors and high production cost. The overall Boal of this research was to develop a garlic clove planter which maintains a garlic clone upright. Specific objective was investigating planting condition and physical properties of garlic clove. The results were summarized as fellows : Based on the survey results, a garlic clove planter should have a planting capacity of at least 140 cloves in a pyung (3.3m$^2$) with the row spacing of 140mm and hill spacing of 120mm for a productive cultivation.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.373-382
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• 1993

A non-contact sensor for detecting distance from field surface to a predetermined location of a tractor will be useful to control precise height of implements such as tillage machinery, mowers etc.. An optical and an ultrasonic sensors were designed and fabricated . The indoor and outdoor experiments were conducted to obtain the static and dynamic characteristics of the two sensors at several moisture levels of four soils and on the soil surface with a designed shape. The results revealed that the optical sensor is unsuitable for soils with high moisture content but showed better detecting accuracy on the irregularity of soil surface.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2006년도 춘계 종합학술대회 논문집
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• pp.342-346
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• 2006

그 동안 기술적 또는 이론적 배경의 취약으로 인하여 측정이 매우 어렵거나 불가능했던 유량을 산정하는데 유효하게 적용할 수 있으며, 형상에 관계없이 측정비용 및 시간을 많이 줄일 수 있다. 더욱이 전자파 표면 유속계와 함께, 실시간 유입수문곡선을 만들 수 있는 실시간 유량 측정 시스템을 개발하는데 사용될 수 있다.

• 한국농촌건축학회논문집
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• 제4권2호
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• pp.27-37
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• 2002

From the point of tectonic manner which is 'how to build a house' this study considers the characteristics of Kan in Hyangdan(香壇) at Yang-Dong Village. It was analysed with primary elements such as Kan, condition of a site, module, structural system, roofing system and their relationships in spatial and formal composition. Through the analysis, findings were achieved that characteristics of Kan to form a rectangle of 1 to root 2 proportion plan, enable irregularity in usage and regularity in compositional aspect and structural system to achieve intended roof design. In addition, Kan as a module is found to have a relative value that also regulates the whole in structural and aesthetical aspects.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.876-879
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• 1996

The vibration of an attractive magnetic levitation(Maglev) vehicle transportation system is caused by the irregularity of the guideway track and the performance of the suspensions of the Maglev system. It is essential for us to give attention to the secondary suspension of the vehicle system as it determines the ride quality. In order to improve the ride quality and running stability, active secondary suspensions have been developed and applied to the vibration problems. This paper analyzes the performance of the active secondary suspension which is applied to an attractive magnetic levitation vehicle system running on a rough track. The dynamics of the suspension system and the optimal control problems are studied. According to the transient and frequency response analyses to the track disturbance, the ride quality of an attractive Maglev vehicle has been improved by applying the designed LQR active controller, and it has been confirmed that this improvement was also influenced by the configuration of the system.

• Journal of Magnetics
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• 제17권4호
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• pp.298-301
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• 2012

In order to know the effect of surface irregularity in the detection of local wall thinning of pipeline using pulsed eddy current (PEC), the lift-off effects on PEC signal have been investigated. Three kinds of parameters in the PEC signal, which is "peak amplitude", "time to peak amplitude" and "time to zero crossing" are analyzed to separate the lift-off effects in the PEC signal. The distance from sensor to the bottom of sample which is the total thickness of combined insulator and sample is kept constant. The magnitude of the differential peak amplitude is increased with increasing sample thickness, the time to peak amplitude is increased with increasing the sample thickness. To determine the effect of lift-off, a number of balanced transient responses combining wall thinning locations and lift-off distances were plotted.

• Interaction and multiscale mechanics
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• 제3권4호
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• pp.333-342
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• 2010

The Pseudo-Excitation Method (PEM) is applied to study the stochastic space vibration responses of train-bridge coupling system. Each vehicle is modeled as a four-wheel mass-spring-damper system with two layers of suspension system possessing 15 degrees-of- freedom. The bridge is modeled as a spatial beam element, and the track irregularity is assumed to be a uniform random process. The motion equations of the vehicle system are established based on the d'Alembertian principle, and the motion equations of the bridge system are established based on the Hamilton variational principle. Separate iteration is applied in the solution of equations. Comparisons with the Monte Carlo simulations show the effectiveness and satisfactory accuracy of the proposed method. The PSD of the 3-span simply-supported girder bridge responses, vehicle responses and wheel/rail forces are obtained. Based on the $3{\sigma}$ rule for Gaussian stochastic processes, the maximum responses of the coupling system are suggested.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.71-76
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• 2008

This paper is concerned with the active vibration control of elevator by means of the active roller guide. To this end, a dynamic model for the horizontal vibration of the elevator consisting of a supporting frame, cage and active roller guides was derived using the energy method. Free vibration analysis was then carried out based on the equations of motion. Active vibration controller was designed based on the equations of motion using the LQR theory and applied to the numerical model. Rail irregularity and wind pressure variation were considered as external disturbance in the numerical simulations. The numerical results show that the active vibration control of elevator is possible.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.140-143
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• 2003

Recently, many high-rise reinforced concrete (RC) bearing wall structures of multiple occupancy have been constructed, which have the irregularities of weak (or soft) story and torsion at the lower stories simultaneously. The study compared the eccentricity of such a building predicted by design codes, EC 8, IBC 2000 and UBC 97, and by the test results through a series of shaking table tests of 1:12 model. Based on the comparison of the predicted eccentricity and the test result, the conclusions are drawn as follow: Accidental torsion due to the uncertainty on the properties of structure can be reasonably predicted by using the dynamic analysis with the center of mass being shifted by 5 percent of the dimension of the building perpendicular to the direction of the excitations than by using equivalent lateral force procedure