• 한국식품과학회지
• /
• 제22권3호
• /
• pp.319-324
• /
• 1990

두유를 저장하고 유통하는 중에 크림층 분리와 침전물의 발생 등 현학안정성에 미치는 pH, 단백질과 유지함량, 유화제, 안정제, 당, 식염 및 칼슘염의 영향을 조사하였다. 두유현탁액은 pH가 증가할수록 침전의 발생이 적어져 pH 10에서는 저장하는 동안에 침전이 전혀 생성되지 않았다. 각종 안정제 중 0.03%의 카라기난을 첨가시 안정성이 가장 좋았으며 팜유를 1.5% 첨가시 glycerine monostearate와 sorbitan monostearate 등의 HLB값은 $5{\sim}6$에서 안정효과가 컸다. 두유 중 지방 함량에 따라 점도변화는 크지 않았지만 크림층 분리가 현저하였고 대두유보다는 팜유를 첨가시 안정성이 더 떨어졌다. 설탕 첨가량은 3%까지 안정성에 큰 영향을 주지않았고 식염은 0.5%까지는 첨가량이 증가할수록 안정성이 감소되었다. 각종 칼슘염 중에서는 모두 안정성을 저해하였지만 그 중에서 시트르산칼슘을 첨가시 안정성의 저해정도가 가장 적었다.

• 대한인간공학회지
• /
• 제25권4호
• /
• pp.115-119
• /
• 2006

To investigate the effects of independent suspension technology(IST) of hiking boot on the stability and load of foot, eight participants performed medial and lateral drop landing from 33.4cm height and 85cm distance to uneven surface while wearing normal & IST hiking boots. For the stability of foot during the drop landing, the balance angle & suspension angle and rearfoot angle was analyzed using high-speed video analysis. Also kinetic analysis using the force plate and insole pressure measurement was conducted to analyze vertical & breaking ground reaction force and pressure distribution. Not only the balance angle & suspension angle but also rearfoot angle was improved with IST boots for lateral drop landing. These results indicate the IST boots may have the suspension function which keeps the foot to be stable during landing. However the IST boots did not show any effect for medial landing. This might be related to the hardness of medial part of outsole. Therefore the softer outsole of medial part could be recommended. Furthermore the impact force & breaking force and insole pressure were reduced with IST boot. These results means that IST boot has not only cushioning effect but also good grip effect. Therefore the hiking boots applied the independent suspension function may help to reduce fatigue and prevent injury such as ankle sprain in hiking on uneven surface.

• 한국소음진동공학회논문집
• /
• 제20권5호
• /
• pp.444-452
• /
• 2010

This paper presents design and performance evaluation of electro-rheological(ER) shock absorber for electronic control suspension(ECS). In order to achieve this goal, a cylindrical ER shock absorber that satisfies design specifications for a mid-sized commercial passenger vehicle is designed and manufactured to construct ER suspension system for ECS. After experimentally evaluating dynamic characteristics of the manufactured ER shock absorber, the quarter-vehicle ER suspension system consisting of sprung mass, spring, tire and the ER shock absorber is constructed in order to investigate the ride comfort and driving stability. After deriving the equations of the motion for the proposed quarter-vehicle ER suspension system, the skyhook controller is implemented for the realization of quarter-vehicle ER suspension system. In order to present control performance of ER shock absorber for ECS, ride comfort and driving stability characteristics such as vertical acceleration and tire deflection are experimentally evaluated under various road conditions and presented in both time and frequency domain.

• 한국기계기술학회지
• /
• 제13권2호
• /
• pp.45-54
• /
• 2011

A vehicle suspension system performs two functions, the ride quality and the stability, which conflict with each other. Among the various suspension systems, an active suspension system has an external energy source, from which energy is always supplied to the system for continuous control of vehicle motion. In the process of the linearization for the nonlinear active suspension system, the frequency dependent damping method is used for the exact modelling to the real model. The pressure control valve which is controlled by proportional solenoid is the most important component in the active suspension system. The pressure control valve has the dynamic characteristics with 1st order delay. Therefore, It's necessary to adopt the lead compensator to compensate the dynamics of the pressure control valve. The sampling time is also important factor for the control performances. The sampling time value is proposed to satisfy the system performances. After the modelling and simulation for the pressure control valve and vehicle dynamic, the performances of the vehicle ride quality and the stability are enhanced.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2000년도 추계학술대회 논문집
• /
• pp.476-483
• /
• 2000

Like other vehicles, the suspension elements of railway rolling stock have influence on running stability and ride quality. Thus, faults detection for suspension elements is important to prevent an accidents of train and to ensure safety against derailment. This study was started to grasp the feasibility of diagnostic method for the suspension elements of bogie without disassembling. Through several tests by running test rig, we found that fault detection for suspension elements was possible. Here, we describe some results.

• 한국군사과학기술학회지
• /
• 제13권6호
• /
• pp.967-975
• /
• 2010

There have been a lot of efforts on the improvement for the ride comfort and handling stability of the combat vehicles. Especially most of vehicles for military purpose have bad inertial condition and severe operating condition such as the rough road driving, and need a high mobility in the emergency status. It is necessary to apply the controlled suspension system in order to improve the vehicle mobile stability and ride comfort ability of crews. A feasibility study is performed on the application of the semi-active suspension system with a magneto-rheological controlled shock absorber for a $6{\times}6$ combat vehicle. First, the dynamic simulation model of the vehicle including the control model for the semi-active suspension system was executed. Based on this model, a hardware-in-the-loop simulation(HILS) system which has a semi-active suspension controller hardware was constructed. After full vehicle simulations were performed in virtual proving courses with this system, the semi-active suspension system was proven to give better ride comfort and handling stability in comparison with the conventional passive suspension system.

• 한국자동차공학회논문집
• /
• 제16권3호
• /
• pp.118-126
• /
• 2008

The levitation stability of a Maglev vehicle utilizing electromagnetic suspension is primarily influenced by the deformation, roughness, and vibration of the guideway. Optimum design for both the vehicle and the guideway is desirable in order to reduce guideway construction cost, while meeting requirements for stability and ride quality. This paper presents an analysis of the levitation stability of the UTM-01, an urban Maglev vehicle, using a numerical simulation. The ODYN/Maglev, a dynamics analysis program, is used to simulate dynamics to evaluate the stability. A running test of the UTM-01 is also carried out to verify the results of the simulation. Using the simulation results, the levitation stability of the UTM-01 can be numerically analyzed at a variety of vehicle speeds.

• 조명전기설비학회논문지
• /
• 제29권10호
• /
• pp.104-110
• /
• 2015

The disturbance observer (DOB) controller has been widely used in various industrial applications since it is capable of achieving robust stability and disturbance rejection. In this paper, we study the effect of Q-filter on disturbance observer controller for Electro-Magnetic suspension (EMS) systems. We consider three Q-filters and analyze their effects on the robust stability against parameter uncertainties due to mass variation. Moreover, we investigate the influence of sensor noise for three Q-filters. According to our study, robust stability improves as the order of Q-filter decreases. On the other hand, the larger the order of Q-filter, the more the effect of sensor noise can be removed.

• 한국식품과학회지
• /
• 제22권3호
• /
• pp.312-318
• /
• 1990

두유제품을 저장하는 동안 단백질 등의 침전과 지방질의 크림층이 분리되는 현상에 미치는 두유제조 조건의 영향을 검토하기 위해서 분쇄, 균질처리 및 열처리조건이 두유의 현탁안정성에 미치는 영향을 조사하였다. 먼저 $20^{\circ}C$의 물로 마쇄한 것을 blanching시 온도에 반비례하여 질소 용해도지수가 현저히 감소하였으나 $80^{\circ}C$의 물로 마쇄하는 경우 그 감소폭이 $20^{\circ}C$의 경우보다 적었다. 침지 대두를 분쇄하여 단백질 입자가 $53{\mu}$에서 $8{\mu}$으로 작아질수록 침전량이 감소하여 두유의 현탁안정성이 증가하였고 균질처리를 1회한 것보다는 2회 반복처리 한 것이 안정성이 증가하였으며 1회 처리시는 입자의 크기에 따라 차이가 심하였지만 2회 처리시는 그 차이가 감소되었다. 균질처리시 1단계 처리압력이 $200kg/cm^2$까지는 안정성이 증가하였고 팜유를 첨가하여 균질처리를 할 때의 온도가 $80^{\circ}C$까지 온도를 높일수록 안정성이 증가하였다. 두유제품을 살균할 때 열처리온도가 $120{\sim}125^{\circ}C$에서 30분 이상 열처리시에는 안정성이 급격히 감소되었다.

• Wind and Structures
• /
• 제10권2호
• /
• pp.121-133
• /
• 2007

To gain understanding of the applicability of carbon fiber reinforced polymer (CFRP) cable in cable-supported bridges, based on the Runyang Bridge and Jinsha Bridge, a suspension bridge using CFRP cables and a cable-stayed bridge using CFRP stay cables are schemed, in which the cable's cross-sectional area is determined by the principle of equivalent axial stiffness. Numerical investigations on the dynamic behavior, aerostatic and aerodynamic stability of the two bridges are conducted by 3D nonlinear analysis, and the effect of different cable materials on the wind resistance is discussed. The results show that as CFRP cables are used in cable-supported bridges, (1) structural natural frequencies are all increased, and particularly great increase of the torsional frequency occurs for suspension bridges; (2) under the static wind action, structural deformation is increased, however its aerostatic stability is basically remained the same as that of the case with steel cables; (3) for suspension bridge, its aerodynamic stability is superior to that of the case with steel cables, but for cable-stayed bridge, it is basically the same as that of the case with steel stay cables. Therefore as far as the wind resistance is considered, the use of CFRP cables in cable-supported bridges is feasible, and the cable's cross-sectional area should be determined by the principle of equivalent axial stiffness.