• Water for future
• /
• v.24 no.1
• /
• pp.83-92
• /
• 1991

The purpose of this paper is to estimate river maintenance water of the main gauging stations in Geum river watershed. The estimation methods of river maintenance water are classified into two categories : views of supply and demand. The definition of river main-tenance water in this paper, is the maximum value between mean drought flow and environmental conserving flow. In order to estimate river maintenance water, the mean drought flow estimated at the upstream of the Daecheong Dam but the downstream of the Daecheong Dam estimated mean drought flow and water quality control flow use of QUAL2E Model. In result, a mean drought flow showed large value at the Gong ju and Gyu am station as the downstream of the Daecheong Dam. The river maintenance water is 33.82$m^3$/sec at the Gong ju station, 51.51$m^3$/sec at the Gyu am station. Therefore, an estimation of the river maintenance water in the Geum River watershed concluded suitability which is determined mean drought flow.

• Korean Journal of Environmental Agriculture
• /
• v.25 no.2
• /
• pp.174-179
• /
• 2006

Chinese cabbage, Braccica campestris has long been consumed as a staple food for Koreans in various forms of fresh, salted, and fermented Kimchi. Cultivation of the crop under greenhouse has become a general practices to fulfill its off-seasonal consumer's demand. However, agricultural practices of the crop have always accompanied with heavy applications of pesticides caused by severe outbreaks of diseases and pose under warm and humid circumferences. Since dissipation patterns of pesticide residues in/on the crop under greenhouse conditions ate quite different from those in the open-air, changes of diazinon, O,O-diethyl O-2-isopropyl-6-methylpyrimidin-4-yl phosphornthioate, in/on the Chinese cabbage applied by foliar spraying under greenhouse were studied. Diazinon 34% EC was applied with dilution of recommended and double dose to the crop. The shoots of crop were harvested immediately after this application and at regular intervals over a 10-day. After sample preparations, the diazinon residue was analyzed using gas chromatography equipped with electron capture detector (GC/ECD). Initially deposited amount of the chemical in/on the crop right after applications with recommended and double doses were 8.3 and 15.2 mg/kg, respectively. The residue levels after 10 days of application were 0.03 and 0.09 mg/kg with 1.3 and 1.5 days of half-life in/on the crop, respectively. In consequent 10 days of pre-harvest interval (PHI) for diazinon EC formulation in/on Chinese cabbage under greenhouse condition was fulfill maximum residue level set by Korea Food and Drug Administration (KFDA, 0.1 mg/kg).

• Applied Chemistry for Engineering
• /
• v.23 no.3
• /
• pp.297-301
• /
• 2012

Microbial fuel cell (MFC) is the major of bio-electrochemical system which can convert biomass spontaneously into electricity through the metabolic activity of the microorganisms. In this study, we used an activated sludge as a microbial inoculum and then investigated the feasibility of using dairy wastewater as a possible substrate for generating electricity in MFC. To examine the performance of MFC as power generator, the characteristics on cell potentials, power density, cyclic voltammetric analysis and sustainable power estimation were evaluated for dairy wastewater. The maximum power density of $40\;mW/m^2$was achieved when the dairy wastewater containing 2650 mg/L COD was used, leading to the removal of 88% of the COD. The results from this study demonstrate the feasibility of using MFC technology to generate electricity while simultaneously treating dairy wastewater effectively.

• Journal of Navigation and Port Research
• /
• v.30 no.8 s.114
• /
• pp.617-622
• /
• 2006

Gamcheon Harbor was developed to cope with increased freight demand of Busan port and supplement function of the north port. Because container wharf is opened to 1997 as well as general wharf, present maximum 50,000DWT class containerships have been incoming and outgoing. However, In Gamcheon port, small size ships such as fishing boats, miscellaneous boats account for 50 percent of the traffic and a public marine products wholesale market that is building on the north wharf will open in 2008. Therefore, it needs to grasp future year traffic volume before establishing operation plan for port management. Also, analysis on crossing situation risk is required because the breakwater entrance in Gamcheon Harbor is narrow and the crossed passing of ship is ever-present at breakwater front. Thus the traffic volume in the future was presumed and quantitative analysis was achieved on crossing situation though simulations with the traffic volume.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.5
• /
• pp.397-404
• /
• 2017

The purpose of this study is to evaluate the seismic performance of Staggered Truss Frame(STF) system while changing a shape of truss. The model of this project is a office building of ten floors with Pratt, Howe, Warren, K and Vierendeel truss system applied on each model. Next step is to select the section of elements which satisfy the highest demand capacity ratio by structure design considering gravity load, earthquake load and wind load and then calculate natural period, base shear and story drifts. On the basis of these values, Capacity Spectrum Method(CSM) shows the plastic behavior of STF system such as performance point of Design Earthquake(DE) and Maximum Considered Earthquake(MCE), yield state, plastic hinge etc. to be compared with other truss systems. As a result, Vierendeel STF system especially was found to have the highest strength and stiffness to the corresponding earthquake and all the models for each truss shape fulfilled the target performance level.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.7
• /
• pp.1223-1232
• /
• 2017

Cordyceps militaris, a member of Ascomycota, a mushroom referred to as caterpillar Dong-chung-ha-cho, is commercially valuable because of its high content of bioactive substances, including cordycepin, and its potential for artificial cultivation. Cordycepin (3'-deoxyadenosine) is highly associated with the pharmacological effects of C. militaris. C. militaris is heterothallic in that two mating-type loci, idiomorph MAT1-1 and MAT1-2, exist discretely in two different spores. In this study, nine C. militaris strains were mated with each other to prepare newly bred strains that produced a larger amount of cordycepin than the parent strains. Nine strains of C. militaris were identified by comparing the internal transcribed spacer sequence, and a total of 12 single spores were isolated from the nine strains of C. militaris. After the MAT idiomorph was confirmed by PCR, 36 mating combinations were performed with six single spores with MAT1-1 and the others with MAT1-2. Eight mating combinations were successfully mated, producing stroma with perithecia. Cordycepin content analysis of all strains by high-performance liquid chromatography revealed that the KASP4-bred strain produced the maximum cordycepin among all strains, regardless of the medium and stroma parts. Finally, universal rice primer-PCR was performed to demonstrate that the bred strains were genetically different from the parental strains and new C. militaris strains. These results may be related to the recombination of genes during mating. The newly produced strains can be used to meet the industrial demand for cordycepin. In addition, breeding through mating suggests the possibility of producing numerous cordycepin-producing C. militaris strains.

• Journal of the Korean Ceramic Society
• /
• v.50 no.6
• /
• pp.498-503
• /
• 2013

Over the past decade, the feasibility of using ink-jet printing for the decoration of porcelain tiles has been explored, and significant advances have been made regarding the technologies underlying printing system and materials. An ink-jet printing system for porcelain tiles has many advantages compared with a conventional printing system, including the following: (1) it is a digital process; (2) it uses non-contact printing; (3) it allows random image generation; (4) it is a highly efficient process (reduced production cost); (5) it offers massive and continuous production; and (6) it uses inorganic pigment colorants. For these reasons, ink-jet printing systems for porcelain tiles have been commercialized and are at present rapidly spreading toceramics-leading countries such as Spain, Italy, China and Japan. We also developed a proprietary system involving a piezo-electric drop-on-demand method and an ink-circulation step. The resolution of this system is greater than 360 dpi after a heat treatment and the maximum printable width is 600 mm, even when setting the printing head unit with four digital colors (cyan, magenta, yellow, and black). In addition, we systematically developed ceramic colorant-containing inks and tile-printing technology applicable to our ink-jet printing system.

• Korean Chemical Engineering Research
• /
• v.43 no.2
• /
• pp.243-248
• /
• 2005

Membrane pervaporation processes could have advantages over distillation for separation of water/organics mixtures: a low energy demand and the ability to separate azeotropic mixtures or isomers. Zeolite membranes might show better thermal, mechanical and chemical stabilities than polymer membranes. Water could be effectively separated from water/organic mixtures using the NaA zeolite membrane because of its high hydrophilicity. In this study, water was separated by pervaporation using the NaA zeolite membrane from water/ethanol mixtures. As a mole fraction of ethanol increased, the total permeation flux and the water flux decreased while the separation factor increased, reached a maximum point, and decreased. As an experimental temperature increased, the total permeation flux increased while the separation factor increased at the lower mole fraction of ethanol than 0.8 and it decreased at the higher mole fraction of ethanol than 0.8. The total permeation flux and the separation factor could be maintained constant during the long term experiment longer than 160 hours. It was found that the NaA zeolite membrane synthesized in our study showed better performance on water/ethanol separation than that of a distillation process or PVA polymeric pervaporation membranes.

• Korean Journal of Agricultural Science
• /
• v.37 no.2
• /
• pp.309-314
• /
• 2010

Bale is an operation of collecting livestock feed materials from field crop residue, and mechanization demand on the operation has been increased. Bailers imported from foreign countries such as Japan and European countries have been used, but those models showed improper performance in Korean situations. In recent years, a steel-roller type round baler attachable to medium size tractors(40 to 60 HP) for effective bale operation in Korea was developed. This study was conducted to evaluate field performance of the baler. For proper baling operation, engine speed was greater than 1,800rpm, average traction force and PTO torque were about 4kN and in a range of 380-671Nm, and maximum values were about 7kN and 3,000Nm, respectively. Performance evaluation tests for sudan grass, rice straw, and blue barley showed that field capacity was 0.59ha/h for blue barley and 0.99ha/h for sudan grass and rice straw. Bale weight, diameter, width, and bulk density were in ranges of 176.1~418.4kg, 1.07~1.12m, 1.02~1.04m, and 175.3~454.1kg/$m^3$. Noise sound level during the baling operation was 4dB greater than idle operation condition, which was considered to be ignorant.

• Plant Journal
• /
• v.14 no.1
• /
• pp.47-51
• /
• 2018

This study analyzed the effect of power output reduction in coal fired power generation on the change of system marginal price and green house gas emissions. Analytical method was used for electricity market forecasting system used in korea state owned companies. Operating conditions of the power system was based on the the 7th Basic Plan for Electricity Demand and Supply. This as a reference, I analyzed change of system marginal price and green house gas emission by reduced power output in coal fired power generation. The results, if the maximum output was declined as 29 [%] to overall coal-fired power plant, system marginal price is reduced 12 [%p] compared to before and decreasing greenhouse gas emissions were 9,966 [kton]. And if the low efficiency coal fired power plant that accounted for 30 [%] in overall coal-fired power plant stopped by year, system marginal price is reduced 14 [%p] compared to before and decreasing greenhouse gas emissions were 12,874 [kton].