• Transactions of the Korean hydrogen and new energy society
• /
• v.21 no.1
• /
• pp.12-18
• /
• 2010

Photobiological hydrogen production using Rhodobacter sphaeroides KD131 was studied on the effect of light intensities and nitrogen sources. Media containing malate and glutamate were shown higher hydrogen production rate than that containing succinate and $(NH_4)_2SO_4$ at the $110\;W/m^2$ illumination by halogen lamp at $30^{\circ}C$. Media lacking glutamate as the nitrogen source exhibited higher hydrogen production than that containing glutamate. Initial cell concentration was optimized to 1.0 at the absorbance of 660 nm. Hydrogen production was increased by increasing the light intensity from 0 to $216\;W/m^2$ but the increasing rate declined over $108\;W/m^2$.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.7
• /
• pp.1590-1596
• /
• 1995

The energy release rates for a dynamically growing crack in orthotropic materials are expressed explicitly in terms of dynamic stress intensity factors. The stress functions suitable for the problem are found and the evaluation of the J-integral for the theoretical singular crack tip fields yields energy release rates. The present results are simpler than the existing ones and can be reduced to the well known solutions in special cases. Examples of extracting stress intensity factors from the finite element solution using the present results are given for the dynamically growing crack problem of orthotropic materials.

• Proceedings of the KSME Conference
• /
• 2001.06a
• /
• pp.389-394
• /
• 2001

The notched Charpy and Izod impact tests arc the most prevalent techniques used to characterize the effects of high impulse loads on ploymeric materials. An analysis method for rubber toughened PVC is suggested to evaluate critical strain energy release rates(Gc) from the Charpy impact energy measurements. An Instrumented Charpy impact tester was used to extract ancillary information concerning fracture properties in addition to total fracture properties and maximum critical loads. The stress intensity factor Kd was computed for varying amounts of rubber contents from the obtained maximum critical loads and also toughening effects were investigated as well.

• KIEAE Journal
• /
• v.13 no.1
• /
• pp.133-140
• /
• 2013

The purpose of this study was to test the effectiveness of the light-shelf system combined with IT to save lighting energy in resident space. According to the multiple variables that affected intensity of illumination, various experiments were designed and conducted. The main findings of this study were following: (1)the optimal level of light-shelf system was formulated which met the appropriate range of intensity of illumination in living-room; (2)although the mixed light-shelf system indicated a high performance, it could often provide discomforts to residents according to the degree of exposure; (3)artificial lights using light-shelf system combined with IT showed a higher effectiveness than those using fixed light-shelf system displayed. This study provided initial information of light-shelf system formative processes that could contribute to the lighting energy diminution. Future studies should focus more on multiple approaches regarding different types of resident space planning.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.837-840
• /
• 2002

An analysis method for rubber toughened PVC is suggested to evaluate critical dynamic strain energy release rates($G_c$) from the Charpy impact energy measurements. An instrumented Charpy impact tester was used to extract ancillary information concerning fracture parameters in addition to total fracture energies and maximum critical loads. The dynamic stress intensity factor $K_{Id}$ was computed for varying amounts of rubber contents from the obtained maximum critical loads and also toughening effects were investigated as well. The fracture surfaces produced under low velocity impact fur PVC/MBS composites were investigated by SEM. The results show that MBS rubber is very effective reinforcement material for toughening PVC.C.

• Water for future
• /
• v.9 no.1
• /
• pp.47-54
• /
• 1976

The research are intend to establish the design criteria for slopy upland reclamation, with protecting the loss of top-soil, Recently undertaken reclamation works for developing the slopy upland of 310,000 ha. have faced to the vagueness of their deign criteria. One of the most influencing factors to cause the soil erosion depends basically upon the kinematic energy of rainfall, which is developed by the rainfall intensity. Their relationship between the rainfall and its kinematic energy is expressed as EK=916+ 331 log I. Consequently, the study was carried out through analyzing each intensity of the independant rainfall through out the 14 rainfall stations. About 10,000 single storms self recording chart of more than 10mm of rainfall amout were collected and analyzed by computer. The results of research show their kinematic energy for the 14 stations, and will be available for the establishment of the design oriteria.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.9 no.1
• /
• pp.67-73
• /
• 2010

Finding sufficient supplies of clean energy for future is one of the society's most important challenges according to technologies. Alternative renewable energy source such as sun energy can be substituted for exceeding human energy need. The main factor affect to solar performance is a collective intensity. To enhance intensity, suitable equipment is a solar tracker. This paper presents design and evaluation of 1 layer polar motion control system for solar tracker suitable for building integrated system. To evaluation of tracking accuracy and adaptability, solar tracker with 64 links is implemented. In experimental results, the accuracy of tracking has under ${\pm}0.0287^{\circ}$ and the thickness has under 140mm.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.59 no.4
• /
• pp.364-371
• /
• 2010

In this paper, we propose the landscape lighting power control system with solar sell generator equipment for energy saving, and also which is included the landscape lighting power transformation device. The power transformation device can check inverse current in the power of the solar cell module and control the power of the battery. And we present the design of landscape lighting power control system. The power control system uses microprocessor with charging system and power transformation device. And also it can control the power of loads under consideration intensity of illumination. The landscape lighting loads are composed of LED(Lighting Emitting Diode) and HID(High Intensity Discharge)lamps. To evaluate property, we installed the solar cell array which generate three kilo watt power. Experimental results show that the proposed system can have stability and energy saving on the mixed configuration of electric loads with DC and AC lamps.

• Applied Chemistry for Engineering
• /
• v.5 no.2
• /
• pp.255-262
• /
• 1994

Arc melted Ti-5Bi alloy was oxidized by thermal oxidation method. In the present study free energy efficiency(${\eta}_e$) of titanium oxide electrode(TOE) was measured as a function of light intensity and light energy. Flat-band potential of TOE was measured as a function of the light intensity and the solution pH. The ${\eta}_e$ of TOE increased with the increase of light intensity and tight energy to maximum value of 3.2% and 13%, respectively, at $0.2W/cm^2$ and 4.0eV. The ${\eta}_e$ was strongly dependent on the magnitude of the bias voltage. Maximum value was found at 0.5V bias. Photocurrent of TOE was controlled by electron-hole pair generation in depletion layer. The flat-band potential of the illuminated TOE shifted to -0.065V/decade with increasing light intensity. With the decrease of pH of electrolyte, flat-band potential shifted to anodic direction. The experimental slope was in good agreement with the Nernstian value of 0.059V/pH decade.

• The Magazine for Energy Service Companies
• /
• s.1
• /
• pp.50-55
• /
• 1999