• Journal of the Korean Society of Propulsion Engineers
• /
• v.14 no.3
• /
• pp.79-86
• /
• 2010

The characteristics and classification of UAV power plants were studied. The energy source for electric generation and power source for internal combustion engine for UAVs were compared. The advantage and drawbacks of power plants were analyzed respectively and the performance demand condition was suggested for next generation UAV power plant finally.

• Nuclear Engineering and Technology
• /
• v.29 no.4
• /
• pp.280-290
• /
• 1997

The robust controller for the nuclear reactor power control system is designed. The nuclear reactor is modeled by use of the point kinetics equations and the singly lumped energy balance equations, Since the model is not exact, the controller which can make the actual system robust is necessary. The perturbed plant is investigated by employing the uncertainties of the initial power level and the physical properties, and by introducing the delay into the modeled plant The overall system is configured into the two port model and the H$\infty$ controller is designed. In designing the H$\infty$ controller, two factors of the loop shaping and the permissible magnitude of control input are taken into account The designed controller provides the sufficient margins for the robustness, and the transients of the system output power and the control input satisfy their associated requirement.

• Journal of Plant Biology
• /
• v.33 no.4
• /
• pp.277-283
• /
• 1990

Inactivation and reactivation of photosynthetic oxygen evolving complex were studied with isolated spinach (Spinacia oleraceda. L.) photosystem II particles by the activity of oxygen evolution and chlorophyll fluorescence. When the particles were treated with Tris and urea, the oxygen evolution was inactivated and three polypeptides having molecular weights of 33 kDa, 24 kDa and 18 kDa were simultaneously released. But in NaCl-treated particles, two polypeptides of 24 kDa and 18 kDa were removed from PS II particles. The oxygen evolution activities of Tris and urea-treated particles were not restored by adding cation ions (Mg2+, Mn2+ and Ca2+), but the NaCl-treated particles were restored by exogenously added Ca2+. The removal of these extrinsic polypeptides, especially 33 kDa, markedly showed the decrease of the variable fluorescence (Fv). These results are likely to be due to dissipate thermal energy by antenna of photosystem II complexes.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.11a
• /
• pp.609-612
• /
• 2007

The co-combustion of coal and RPF(Refuse Plastic Fuel) mixture has been experimented in a commercially operating CFB coal boiler and the emissions such as SOx, NOx, TSP and dioxine were measured at the stack. The experimented RPF was supplied by domestic RPF company that is commercially producing RPF pellet from the wasted plastics. Up to 15% of total coal was substituted to RPF and no trouble was happened during normal boiler operation. SOx and NOx concentration was reduced about $15{\sim}20$% and TSP(Total Suspended Particle) was drastically reduced about 30% during co-combustion. Dioxine concentration at mixing ratio of 7.5% was $0.0487ng{\sim}TEQ/Sm^3$ ($O_2$, 12%) that satisfied governmental emission regulation.

• Journal of Plant Biotechnology
• /
• v.36 no.3
• /
• pp.202-206
• /
• 2009

In many countries including China and U.S., researchers are developing methods to use sweetpotato as raw material for biofuel. We consider the sweetpotato is not only a source of green fuel, it eventually will provide various material including paper, adhesives, biodegradable plastics, and secondary metabolites. Sweetpotato is one of the high efficiency crop because it yields more calories per unit area than either maize or potato, and it requires the shortest growing cycle of the root crops grown in the tropics. Sweetpotato is the most useful crop for the coming starchbased industry era. Sweetpotato genetic resources are collected, characterized, evaluated, and maintained by U.S., China, Japan, and the International Potato Center. New varieties of sweetpotato using the proper genetic resources and molecular breeding will be developed to cope with the global food and energy in 21st century.

• Journal of Korean Society on Water Environment
• /
• v.32 no.4
• /
• pp.343-348
• /
• 2016

A chemical sequencing batch reactor was operated to test the feasibility of nutrient recovery from a biological livestock wastewater treatment plant. Both phosphate and ammonia could be successfully recovered as magnesium ammonium phosphate (MAP) crystals. The contents of TP and TN in the recovered MAP crystals were 26.2% and 4.0%, respectively. Zn, Cr and Ti were identified in the crystals, but the contents remained below the Korean standard for an organic fertilizer. Chemical analyses confirmed that the MAP crystals could be useful phosphate fertilizers. On the other hand, the results of physical analyses using an X-ray diffractometer and an energy dispersive X-ray spectrometer strongly suggested that crystalline materials like magnesium potassium phosphate (KMP) and hydroxyapatite (HAP) were also formed during the MAP crystallization, depending on the availability of K⁺ and Ca²⁺.

• Journal of Forest and Environmental Science
• /
• v.24 no.3
• /
• pp.171-174
• /
• 2008

The increasing price of liquefied petroleum gas (LPG) has forced many households to shift to firewood/charcoal in the Philippines, causing tremendous pressure on the dwindling forest. This transition is more obvious in the rural area where firewood price is almost half of that in the cities. Both problems on big demand for firewood and the pressure on our forest can be partly solved by going into firewood plantation. After all, the country has vast track of idle lands, both private and government lands, waiting to be developed. What the government can do are: a) aggressive promotion of firewood plantation, b) simplify further the old technology on establishing firewood plantation to encourage more farmers, c) improve charcoal processing and d) promote the use of efficient stoves. This write up discusses the need for firewood plantation, areas available for planting, where to plant in farms, what species to plant in a particular soil type/location for optimum growth, planting methods, harvesting, marketing, and the side lights on the ecological benefits derived from plantation aside from wood.

• Journal of Industrial Technology
• /
• v.33 no.A
• /
• pp.23-30
• /
• 2013

Tidal power generation is to produce electrical energy from fluctuations of the ebb and flow in a constructed embankment. More specifically, the sinusoidal variations of tidal flow, along with the periodicity and changes in the height of waves over time make the tidal power generation possible at a certain tidal level. This paper proposes a more practical efficiency test method for tidal power plant generator that utilizes the axis torque changing values rather than the retardation method which is commonly used. The proposed method was compared with the conventional method and the test result shows that proposed method provides a similar accuracy with the conventional retardation method and a better efficiency.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.29 no.7
• /
• pp.449-453
• /
• 2016

The amount of electrical energy has been increased with the rapid development of the industrial society. Accordingly, operating voltage of the power equipment and facility capacity are continuously increasing. Development trends of recent high-voltage electrical equipment are ultra high-voltage, large-capacity and compact. Early diagnosis of a failure of the power plant has been emerging as an important task as to supply high quality power to users. In this study, we have tried to develope an algorithm for distinguishing an arc fault signal generated in the power plant by using UV sensor.

• Journal of Electrical Engineering and Technology
• /
• v.8 no.1
• /
• pp.46-52
• /
• 2013

Economic properties of an integrated wind power plant (WPP) and the demand response (DR) programs in the sample electricity market are studied. Time of use (TOU) and direct load control (DLC) are two of the DR programs that are applied in the system. The influences of these methods and the incentive payments by market operator's (MOs) with variable elasticity are studied. It is observed that DR with TOU and DLC programs together yields better revenue and energy saving for MOs.