• Journal of Crop Science and Biotechnology
• /
• v.10 no.4
• /
• pp.257-264
• /
• 2007

Rice is one of the world's staple crops and is a major source of carbohydrate. Rice is exported from several countries, providing a major source of income. There are many documents reporting that rice is a salt-sensitive crop in its developmental stages. The objective of this investigation is to evaluate the effective salt-tolerance defense mechanisms in aromatic rice varieties. Pathumthani 1(PT1), Jasmine(KDML105), and Homjan(HJ) aromatic rice varieties were chosen as plant materials. Rice seedlings photoautotrophically grown in-vitro were treated with 0, 85, 171, 256, 342, and 427 mM NaCl in the media. Data, including sodium ion$(Na^+)$ and potassium ion$(K^+)$ accumulation, osmolarity, chlorophyll pigment concentration, and the fresh and dry weights of seedlings were collected after salt-treatment for 5 days. $Na^+$ in salt-stressed seedlings gradually accumulated, while $K^+$ decreased, especially in the 342-427 mM NaCl salt treatments. The $Na^+$ accumulation in both salt-stressed root and leaf tissues was positively related to osmolarity, leading to chlorophyll degradation. In the case of the different rice varieties, the results showed that the HJ variety was identified as being salt-tolerant, maintaining root and shoot osmolarities as well as pigment stabilization when exposed to salt stress or $Na^+$ enrichment in the cells. On the other hand, PT1 and KDML105 varieties were classified as salt-sensitive, determined by chlorophyll degradation using Hierarchical cluster analysis. In conclusion, the HJ-salt tolerant variety should be further utilized as a parental line or genetic resource in breeding programs because of the osmoregulation defensive response to salt-stress.

• Journal of Energy Engineering
• /
• v.26 no.4
• /
• pp.45-56
• /
• 2017

Coal power plants produce electricity for the nation's power grid, but they also produce more hazardous air emissions than any other industrial pollution sources. The quantity is staggering, over 386,000 tons of 84 separate hazardous air pollutants spew from over 400 plants in 46 states. In South Korea also, annual coal ash generation from coal-fired power plants were about 6 million tons in 2015. Pollutants containing particulate matter 10, 2.5 (PM10, PM2.5), heavy metals and dioxins from coal-fired power plant. The emissions threaten the health of people who live near these power plants, as well as those who live hundreds of miles away. These pollutants that have long-term impacts on the environment because they accumulate in soil, water and animals. The present study is to investigate the physical and chemical characteristics of coal-fired power plant fly ash and bottom ash contains particulate matter, whose particulate sizes are lower than $PM_{10}$ and $PM_{2.5}$ and heavy metals. There are wide commercial technologies were available for monitoring the PM 2.5 and ultra-fine particles, among those carbonation technology is a good tool for stabilizing the alkaline waste materials. We collected the coal ash samples from different coal power plants and the chemical composition of coal fly ash was characterized by XRF. In the present laboratory research approach reveals that potential application of carbonation technology for particulate matter $PM_{10}$, $PM_{2.5}$ and stabilization of heavy metals. The significance of this emerging carbonation technology was improving the chemical and physical properties of fly ash and bottom ash samples can facilitate wide re use in construction applications.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.2 no.3
• /
• pp.32-37
• /
• 1999

There is a need to suggest the standards of selection on the cuttings, because the selection of the willow(Salix) cuttings is very important, which will be used as the bioengineering revegetation material to protect the slope by strengthening soil and preventing soil erosion under the bad site conditions. In this study, we measured the lengths and the diameters of original willow cuttings, the total numbers and the lengths of the new shoots and roots after 15 months since the experimental construction of the slope revegetation technology of biological engineering was conducted, and analyzed the correlation between the lengths and the diameters of willow cuttings and the lengths of new roots using the SPSS program. The results are as follows; First, the lower the elevation of tested slope was, the more the number of new shoots and the average lengths of new roots increased. Secondly, the ratio of underground parts and aboveground parts was 4.24 ~ 5.93 proving the fact that the willow(Salix) is one of the species deep rooted with developed underground parts. Thirdly, there is a strong correlation between the diameters of willow cuttings and the total lengths of new roots, whereas, there is no correlation between the lengths of willow cuttings and the total lengths of new roots. In conclusion, it is more efficient for the early rapid revegetation and slope stabilization to select willow cuttings with the biggest possible diameters than with the longest lengths as the slope revegetation materials of biological engineering.

• Korean Journal of Acupuncture
• /
• v.19 no.2
• /
• pp.41-49
• /
• 2002

Objectives : The aim of the present study is to observe effects of acupuncture related with the nerve system, Inferior mesenteric nerve activity(IMNA) was examined on BL60 acupuncture closely connected with the bladder and HT8 with little tied. Materials and methods : Acupunctures were performed during 100 seconds after stabilization. IMNA was measured by micromanipulator, preamplifier, mean arterial pressure(MAP) and heart rate were observed by blood pressure transducer, 4-channel transducer amplifier in anesthetized rat. Results : On BL60 acupuncture, the heart rate was not significantly decreased but IMNA, MAP were significantly decreased and Maximum peak of IMNA was increased during inserted acupuncture, decreased after ejected acupuncture respectively. On HT8 acupuncture, IMNA was decreased during acupuncture than before acupuncture but the others did not showed signigicant difference. Conclusions : Our results demonstrated a meridian interaction between BL60 acupoint in the bladder channel and Inferior mesenteric sympathetic nerve related to the bladder. This fact suggest that BL60 acupuncture have effect on the bladder through the nerve system. Meanwhile, IMNA was decreased during HT8 acupuncture. This result is supposed HT8 to have not meridian function but acupoint function by another mechanism. It needs to be closely examined other meridians and nerve by the optimal approaching method.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.30 no.4
• /
• pp.94-108
• /
• 1988

The use of geotextile as reinforcing materials in soil structures has become widespread throughout the world. Geotextile reinforcement has been used in retaining walls, roadbed, embankment stabilization and especially reinforcement of soft foundation, and so on, In the past, however, its design and construction have been performed empirically. In this study, laboratory model tests were carried out in order to investigate the effects of geotextile rein- forcement on vertical and horizontal displacement and other characteristics in soft founda- tions. The experiments were executed in eight treatments ;no geotextile between embank - ment and subsoils, and seven geotextiles with different tensile strength. And such factors as the loading conditions, the tensile strength of geotextiles, the ingredient of geotextiles and the elapsed time were investigate in this study. And the analytical method were executed in order to study the stress and behavior of geotextile - reinforced soil structure by the nonlinear elasto - plastic finite element model. The following conclusions were drawn from this study. 1. Geotextile reinforcement reduced the effects of banking loads on subsoils more effectively with the increase of their tensile strength. 2. As the tensile strength of geotextiles was increase, the rate of the initial vertical disp - lacements of loading plate was reduced inverse proportional to loads, Rowever, the effect of loading was reduced when the loads exceed a certain limits, 3. The effect of reinforcement of nonwoven geotextile was 1.5-4.5 times larger than that of the woven geotextile with equivalent tensile strength. 4. The increased bearing capacity and the reduced settlement are proportioned as the tensile strength of geotextile. 5. The settlement at the long time loading were developed almost all, were completed after 10 days and the additional settlement were not developed since then. 6. The nonlinear elasto - plastic finite element method are accurate to predict the stresses and behayior of geotextile - reinforced soil structures.

• The Journal of the Korea Contents Association
• /
• v.13 no.7
• /
• pp.432-439
• /
• 2013

In this study, we evaluate the volatility of housing prices by using literature review and empirical analysis and furthermore we suggest how to improve. In order to diagnose housing market, the KB Bank's House Price Index, Real estate 114;s materials were compared. In addition, to examine the volatility, GARCH (Generalized Autoregressive Conditional Heteroskedasticity) and EGARCH (Exponential GARCH) model are used. By analysis of this research, we found the volatility of housing price also was reduced in the medium and the large houses since 1998, while the volatility of small housing price relatively was large. We proved that the price change rate of small housing was higher than the medium's. On the order hand, the supply of small apartments fell down sharply. The short-term oriented policy should be avoided, and the efficiency and credibility of policy should be increased. Furthermore, the long-term policy system should be established. and rental market's improvement is necessary for stabilization of housing market.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.11
• /
• pp.2595-2602
• /
• 2009

Hexamer cluster of N,N-dimethylformamide(DMF) based on the crystal structure was investigated for the equilibrium structure, the stabilization energies, and the vibrational properties in the density functional force field. The geometry (point group $C_i$) of fully optimized hexamer clustered DMF shows quite close similarity to the crystal structure weakly intermolecular hydrogen bonded each other. Stretching force constants for intermolecular hydrogen bonded methyl and formyl hydrogen atoms with nearby oxygen atom, methyl C–H${\cdots}$O and formyl C–H${\cdots}$O, were obtained in 0.055 $\sim$ 0.11 and $\sim$ 0.081 mdyn/$\AA$, respectively. In-plane bending force constants for hydrogen bonded methyl hydrogen atoms were in 0.25 $\sim$ 0.33, and for formyl hydrogen $\sim$ 0.55 mdynÅ. Torsion force constants through hydrogen bonding for methyl hydrogen atoms were in 0.038 $\sim$ 0.089, and for formyl hydrogen atom $\sim$ 0.095 mdynÅ. Calculated Raman and infrared spectral features of single and hexamer cluster represent well the experimental spectra of DMF obtained in the liquid state. Noncoincidence between IR and Raman frequency positions of stretching C=O, formyl C–H and other several modes was interpreted in terms of the intermolecular vibrational coupling in the condensed phase.

• Applied Chemistry for Engineering
• /
• v.16 no.2
• /
• pp.180-186
• /
• 2005

This paper discusses the development of mixtures for silica fume as a stabilization/solidification agent and a binder for industrial wastewater residue containing organic and heavy metal contaminants. The UCS (unconfined compressive strength) gradually increased to 66.7% as the silica fume content increased to 15%. The leaching of TOC (total organic carbon) and chromium decreased as more OPC (Ordinary Portland Cement) was substituted with the silica fume. When a mixture had 5% silica fume, it retained about 85% TOC, and chromium leached out 0.76 mg-Cr/g-Cr in acidic solution. Also, microstructural studies of the solidified analysis showed that the silica fume caused an inhibition to the ettringite formation which did not contrilbute to setting but coated the cement particles and retarded the setting reactions. The results indicated that the incorporation of silica fume into the cement matrix minimized the detrimental effects of organic materials on the cement hydration reaction and the contaminant leachability.

• Korean Journal of Environmental Agriculture
• /
• v.40 no.3
• /
• pp.231-238
• /
• 2021

BACKGROUND: Metal contamination of farmlands nearby abandoned mines is a serious environmental problem. This study was conducted to evaluate the efficiency of stabilizers on different type of the soils contaminated with metals. METHODS AND RESULTS: The texture of silt loam soil initially contaminated with heavy metal was artificially adjusted to loam and sandy loam by adding sand, and the soil organic matter content (1.5%) was also altered by adding peat to the soils at 3.5 and 8.0%. The soils were mixed with 3% (w/w) of each limestone, dolomite, and steel slag. For the soils with different textures, the bioavailability of As was found to be the lowest in sandy loam compared to others metals such as Cu, Pb, and Zn. The efficacy of limestone and dolomite was not significantly different compared to the soils having different organic matter contents, but the stabilization efficiency of steel slag increased as the soil organic matter content increased. Moreover, stabilizers showed inhibition effect on the uptake of metals to plant. CONCLUSION: The stabilizers were found as effective materials to immobilize metals in soil and to decrease plant uptake of metals. Studies are needed to deeply elucidate the interaction between influencing factors and various stabilizers.

• Geomechanics and Engineering
• /
• v.18 no.3
• /
• pp.315-328
• /
• 2019

This paper presents an investigation on bearing capacity, load-settlement behavior and safety factor of rock-soil slopes reinforced using geogrid-box method (GBM). To this end, small-scale laboratory studies were carried out to study the load-settlement response of a circular footing resting on unreinforced and reinforced rock-soil slopes. Several parameters including unit weight of rock-soil materials (loose- and dense-packing modes), slope height, location of footing relative to the slope crest, and geogrid tensile strength were studied. A series of finite element analysis were conducted using ABAQUS software to predict the bearing capacity behavior of slopes. Limit equilibrium and finite element analysis were also performed using commercially available software SLIDE and ABAQUS, respectively to calculate the safety factor. It was found that stabilization of rock-soil slopes using GBM significantly improves the bearing capacity and settlement behavior of slopes. It was established that, the displacement contours in the dense-packing mode distribute in a broader and deeper area as compared with the loose-packing mode, which results in higher ultimate bearing load. Moreover, it was found that in the loose-packing mode an increase in the vertical pressure load is accompanied with an increase in the soil settlement, while in the dense-packing mode the load-settlement curves show a pronounced peak. Comparison of bearing capacity ratios for the dense- and loose-packing modes demonstrated that the maximum benefit of GBM is achieved for rock-soil slopes in loose-packing mode. It was also found that by increasing the slope height, both the initial stiffness and the bearing load decreases. The results indicated a significant increase in the ultimate bearing load as the distance of the footing to the slope crest increases. For all the cases, a good agreement between the laboratory and numerical results was observed.