• Journal of Biosystems Engineering
• /
• 제33권6호
• /
• pp.379-383
• /
• 2008

A CRDI diesel engine used to commercial vehicle was fueled with diesel fuel and 20% biodiesel blended fuel (BDF 20%) and tested at the Seoul-10 mode for 150 hours. Engine dynamometer testing was completed at regularly scheduled intervals to monitor the engine performance and exhaust emissions. To check the engine parts (valve, injector), the engine was inspected after 150 hours running test. It was concluded that there was no unusual deterioration of the engine, or the changes in engine power (below 1.9%), smoke (below 4.1%), NOx (below 3.7%) and durability characteristics in spite of operation of 150 hours run with BDF 20%. The difference of kinetic viscosity for engine oil (before and after durability testing) was below 0.19% at $100^{\circ}C$.

• International Journal of Air-Conditioning and Refrigeration
• /
• 제14권3호
• /
• pp.85-93
• /
• 2006

The present study has been conducted to simulate dynamics of a gas engine-driven heat pump (GHP) for the design of control algorithm. The dynamic model of a GHP was based on conservation laws of mass and energy. For the control of refrigerant pressures, actuators such as an engine throttle valve, outdoor fans, coolant three-way valves and liquid injection valves were controlled by P or PI algorithm. The simulation results were found to be realistic enough to be applied for the control algorithm design. The model could be applied to build a virtual real-time GHP system so that it interfaces with a real controller for the purpose of developing control algorithm.

• Journal of Advanced Marine Engineering and Technology
• /
• 제17권1호
• /
• pp.26-32
• /
• 1993

The loads exerted on electro-hydraulic servo system are classified into inertial, viscous, and spring load. The additional load called disturbances is also exerted on system but is generally not modeled. To deal with these kinds of loads, it is necessary to maintain the continuous signal transfer, so we can construct compensator to satisfy control specifications using feedback signal such as displacement, velocity, acceleration and pressure known as state variables. In case of controlling the speed of hydraulic motor, we must keep up robust performance for the various loads and disturbances acted on the system. However, the load flow rate in the valve is characterized by nonlinearity so that traditional theory of linear control could not be expected to give the desired performance. In this paper, it is shown that speed controller of hydraulic motor gives a good command following and disturbance rejection performance by applying sliding mode theory as a way of robust control to the nonlinearity, variation of loads and disturbances.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.111.6-111
• /
• 2001

A seat suspension system with a controlled MR(Magneto Rheological) fluid damper is introduced to improve the ride quality and prevent the health risk of a driver compared to conventional seats. The system locates between a seat cushion and base, and is composed of a spring, MR fluid damper and controller. The MR fluid damper designed in valve mode is capable of producing a wide range of damping force according to applied currents. In experiments, a person was sitting on the controlled seat excited by a hydraulic system. The skyhook control, continuous skyhook control and relative displacement control were applied and the continuous skyhook control improved the vibration suppression by 36.6%.

• Archives of Pharmacal Research
• /
• 제17권5호
• /
• pp.360-363
• /
• 1994

Column--swtiching technique with a reversed-phase high performance liquid chromatographic method has been developed for the routine analysis of radioiodinated insulin and its degadation products in biological fluids. The diluted biological samples were loaded onto a precolumn packed with LiChrosorb RP-8 $(25-40{\;}{\mu}m)$ using 0.1% trifuoroacetic acid (TFA) in water as a washing solvent. After valve switching, the concentrated insulins were eluted in the back-flush mode and separated by a W-Porex $C_{18}$ column with a gradient of 0.1% TFA in water and 0.1% TFA in acetonitrile as the mobile phase. The method showed good precision, accuracy and speed with the detection limit of 20 pg/ml. Total analysis time per sample was about 40 min and the coefficients of variation were less than 8, 2%.

• 제어로봇시스템학회논문지
• /
• 제8권10호
• /
• pp.861-866
• /
• 2002

A seat suspension system with a controlled MR(Magneto Rheological) fluid damper is introduced to improve the ride quality and prevent the health risk of a driver compared to fixed seats. The system is located between a seat cushion and the base, and is composed of a spring, MR fluid damper and controller. The MR fluid damper designed in valve mode is capable of producing a wide range of damping force according to applied currents. In experiments, a person was sitting on the controlled seat excited by a hydraulic system The skyhook control, continuous skyhook control and relative displacement control were applied and the continuous skyhook control improved the vibration suppression by 36.6%.

• 한국임상수의학회지
• /
• 제21권1호
• /
• pp.83-86
• /
• 2004

A 4 year old mixed female dog was presented dyspnea, anorexia and syncope. In blood smear test, a lot of heartworm larvae were observed. In thoracic radiography, "reverse D" shape was observed. So, this case was considered with heartworm disease. In echocardiography, marked left heart hypertrophy was presented. In M-mode view, aortic valvular stenosis was found. After mongrel dog died, aortic valvular stenosis was reconfirmed in necropsy. After all, the dog died of pulmonary edema because of aortic valvular stenosis caused left heart failure.t failure.

• Journal of Chest Surgery
• /
• 제21권2호
• /
• pp.276-282
• /
• 1988

Surgery is now the usual mode of therapy in patients with severe valvular heart disease. Until recently, clinicians and pathologists attributed nearly all acquired valvular heart diseases to a rheumatic origin, except some obviously resulting from acute infection and syphilis. Although many clinicians and pathologists describe that the origin of aortic valvular disease is a nonrheumatic origin, we recognize the major origin of aortic valvular disease in Korea as a rheumatic origin. We excised 47 cardiac valves from valvular heart diseased patients and performed anatomical and pathological analysis for its origin and underlying pathology. The purpose of this article is to provide an update for the clinicians of evolving issues related to the pathology of valvular heart disease. But myxomatous origin and infective endocarditis valvulitis will not be covered in detail.

• Journal of Chest Surgery
• /
• 제16권4호
• /
• pp.485-491
• /
• 1983

From July 1966 to July 1983, sixteen atrial myxomas in fifteen patients were seen at Severance Hospital. Fifteen of the sixteen myxomas were located in the left atrium and one in the right atrium. All the cases except three were correctly diagnosed preoperatively. Presently, M-mode and two-dimensional echocardiography are utilized as safe, reliable, and noninvasive imaging modalities. Echocardiography provided an accurate diagnosis in twelve cases since November 1977. In all cases, myxoma were excised successfully. On patient had reoperation and mitral valve replacement on postoperative first day due to persist mitral regurgitation after excision of left atrial myxoma. One patient had recurrence requiring reoperation 37 months after primary operation. Follow up results of each patient were excellent.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2006년도 춘계학술대회논문집
• /
• pp.916-921
• /
• 2006

Column mixer is one of the facility to mix fluids at petrochemical plants. The column vibration is caused by pumps for fluid inflow and mixing of inside fluids. This fluid induced vibration is mainly responsible for the reduction of column life. Measurements were performed three times for understanding the vibration characteristics of the column. First experimental results showed the need of stiffness reinforcement. After the reinforcement work, second measurement conformed the difference between two results. Modal analysis was also performed to investigate the resonance of the column vibration and the damage of the rib plate. To confirm the generation of the fluid instability in the column mixer fluid structure interaction analysis using ADINA/FSI was performed which showed the necessity of the modification of the rotary valve.