• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.242-248
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• 2007

To find a feasibility of utilization of food waste slurry (FWS) generated during composting, FWS was combined with pig manure slurry (PMS) in various ratios and the change of nutrient contents and offensive odor of the combined slurries before and after fermentation were studied. The initial pH was 7.67 for PMS and 8.45 for FWS. However, during the fermentation, pH increased in the combined slurries with the higher FWS rate among the treatments while decreased in thosewith higher PMS rate. EC of each slurry sample showed that the difference among combined slurry samples has been reduced during fermentation and became stabilized in $21{\sim}23dS\;m^{-1}$ after 180 days. After 180 days fermentation, total nitrogen (T-N) decreased. T-N of mixture with a half and more FWS decreased up to 0.1%, less than the critical level (0.3%). The contents of O.M., T-N, phosphorus, calcium and magnesium decreased with fermentation while those of potash and salinity increased. From initial fermentation until 30 days, a lot of $NH_3$, as an offensive odor, was produced. However, it decreased steadily, except in higher PMS rate. In terms of producing $50{\mu}g\;ml^{-1}$ of $NH_3$, the top layer took 30 days after fertilization with FWS only, 45 days for utilized treatment with F75 (25 % of PMS), 75 days for utilized with F50 (50%) and F25 (75%) and 90 days for PMS only, respectively. $RNH_2$ also had similar trend with $NH_3$ but it was produced continuously as long fermentation proceeded. In terms of $RNH_2$, the decrease in concentration up to $50{\mu}g\;ml^{-1}$ were; 45 days for FWS only(F100), 105 days for F75 utilization, 120 daysfor F50, 165 days for F25, respectively. ethyl mercaptan was produced in PMS until 180 days after fertilization but it was not produced in FWS. Sensory tests as an integrated test of offensive odor were also done. FWS showed lower than 1 after 30 days from initial fermentation, while PMS had still offensive odor even up to 180 days from initial fermentation. It is probably affected by the continuous production of ethyl mercaptan and amines. However, considering in decrease T-N content caused by volatilization while offensive odor intensity according to official standard of fertilizer is lower than 2. Further study on controlling offensive odor needs to be done.

• Journal of the Korean Geosynthetics Society
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• v.17 no.2
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• pp.41-49
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• 2018

The purpose of this study is to fabricate a full scale road embankment using lightweight air foamed soil as a soil material on soft ground and to investigate its material characteristics and behavior in order to promote dredged soil utilization and minimize ground improvement. As a result of the laboratory test of the onsite mixed samples, the total unit weight of the specimens decreased almost linearly until curing 28 days. In particular, the total unit weight after 28 days of curing was reduced to about 81% of the slurry state before curing, which will be useful in the formulation of similar native soil materials in the future. The unconfined compressive strength began to decrease with the 14th day of curing as shown in the previous study. When the cement content is increased, the strength decreases sharply at a small strain change after the occurrence of the maximum compressive strength, and the maximum strength is exhibited in a range of a smaller axial strain than normal range. The settlement at the surface layer of the ground due to the lightweight embankment was about 1 / 2.75 of the soil embankment and was in agreement with the unit weight ratio (1 / 2.7) of the embankment materials. This indicates the cause and effect of the settlement due to the difference in self weight of the embankments. Also, the difference in settlement between soil and lightweight embankment increased with increasing depth. This shows that the difference in the point at which the settlement is terminated is clear. The ground horizontal displacement under the lightweight embankment was about 15~20% smaller than that of the soil embankment and the depth of occurrence was also 4.5~5.0m shallower in the lightweight embankment.

• Journal of the Korean Geosynthetics Society
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• v.10 no.2
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• pp.73-79
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• 2011

Based on the results of Part 1 of our two-parts paper, the possibility on field applicability of CMDS(Coal Mine Drainage Sludge) mixed with bentonite and cement as a liner in landfill sites was investigated. The optimum moisture content that met the landfill liner condition was obtained when the ratio of CMDS: bentonite: cement was 1: 0.5: 0.3 in a lab-scale. The relative compaction was measured in 90.1%, which results for construction field have been generally acceptable. In this study, a large-scale Lysimeter($1.0m{\times}1.5m{\times}2.0m$) was used to simulate the effects of the layer on the freeze/thaw by -20 average temperature. The mixture after freezing/thawing showed compressive strength more than $5kg/cm^2$, which was satisfied with EPA standards. Initial permeability of CMDS was $7.10{\times}10^{-7}cm/s$ and permeability its mixture after freezing/thawing was increased to $9.80{\times}10^{-7}cm/s$. The change of temperature in the layers rises and falls with linear and temperature gradient keep maintain the present state. Moisture contents in the layers have not been radically changed. Through the leaching test determined by KSLT method, it was found that heavy metals excluding Zn and Ni were not leached out or leached out less than the standards during 7 cycles of freezing/thawing process. Since it shows the increased permeability about 1.5 times and slight change in moisture content, but it was satisfied with EPA standar through 7 cycles of freezing/thawing process, this mixture can be applied as a liner in landfill final cover system.

• Journal of Mushroom
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• v.2 no.2
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• pp.88-96
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• 2004

This study was executed to decide the physiological characteristics of Ferule mushroom. Four strains of Ferule mushroom were tested to select a superior strain in its mycelial growth. The pertinent substrates, temperature and pH ranges for the growth of selected strain were determined. And then, the wood rotting ability and type of the Ferule mushroom were determined. The superior strain F-2 among four strains was selected, on the basis of its vegetative mycelial growth and density on agar media. Mycelial growth of F-2 was the best on MYPA among other tested synthetic or semi-synthetic media. The temperature range for pertinent mycelial growth was about $25{\sim}34^{\circ}C$ and best at $30^{\circ}C$. The optimum pH range on MYPA was 5.0~6.0. The mycelial growth was mostly stimulated by soluble starch at cont. 1% (w/w) and secondly, maltose among several carabon sources and by mixed solution of YE(0.25%) and ME(0.25%) but not by ME alone. Cell thining and erosion of Pinus rigida wood by the mycelia of Ferule mushroom were found only on a few cell but largely at wood block test, indicating that the softwood rotting ability of Ferule mushroom mycelia was not so good. The result of polarized light microscopy appeared that cellulose of some tracheides showing the S3 layer lost brifringence was degraded by Ferule mushroom. But only part of cellulose of P. rigida wood was degraded by Ferule mushroom, because most of wood cells continued to showing briefingence. A largely degraded ray parenchyma and longitudinal parenchyma cell and partly thinning and erosion of hardwood(Quercus serrata) cell was found and it indicates that the rotting ability of Ferule mushroom mycelia on hardwood was higher than on softwood. It could be concluded that the difference in the wood rot by Ferule mushroom between the hardwood and softwood was made by the difference of chemical constitutions between them, especially in the contents and the types of lignin. Ferule mushroom was considered as white rotter as a result of bavendam test, although more research should be required.

• Korean Journal of Poultry Science
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• v.33 no.4
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• pp.255-262
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• 2006

Two experiments were conducted to investigate the effect of dietary organic selenium levels on performance and selenium retention in broiler chickens and laying hens. In experiment 1, the effects of dietary organic selenium levels on the weight gain, feed intake, feed conversion, and selenium retention of meat and liver in broiler chickens were investigated. For each growth phase, the basal diet was supplemented with 0 (control), 0.60, 1.20, 1.80 and 2.40 ppm Se from selenium yeast(SY). Weight gain, feed intake, and feed conversion were not affected by the selenium addition in diets. Breast muscle Se levels were linearly increased (P<0.05) as dietary Se level increased by SY. Selenium concentration of liver tissue was increased (P<0.05) in supplemental SY compared to the control, and was increased (P<0.05) in supplemental 1.20, 1.80 and 2.40 ppm SY compared to the 0.60 ppm SY. In Experiment 2, 12-week-experiment using Hy-Line laying hens (68 wk of age) was conducted to examine the effects of dietary organic selenium on egg Production, egg weight, daily egg mass, feed intake, feed conversion, egg quality, and selenium concentration of eggs. A corn-soybean meal basal diet was supplemented with 0 (control), 0.30, 0.60, 0.90 and 1.20 ppm Se from selenium yeast (SY). Egg Production was significantly improved(P<0.05) in supplemental 0.30 and 0.90 ppm SY compared to the control and 0.60 ppm SY during week 1 to 12, but daily egg mass, feed intake, and feed conversion showed no difference in supplemental SY and control. Haugh unit, yolk color and eggshell breaking strength showed no difference in supplemental SY and control. Eggshell thickess was significantly (P<0.05) higher in supplemental 0.60 and 1.20 ppm SY compared to the 0.90 ppm SY in week 9. Egg Se levels were linearly increased (P<0.05) as dietary Se level increased by SY.

• Korean Journal of Agricultural Science
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• v.9 no.1
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• pp.357-370
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• 1982

Recent concern regarding price and availability of fossil fuels has spurred the interest in alternative sources for farm crop drying. Among the available options such as biomass energy, wind power, nuclear energy and solar energy etc., the increasing attention is being directed to the utilization of heat from solar energy especially for farm crop drying. Even though solar energy is dispersed over a large land area and only a relatively small amount of energy can be simply collected, the advantages of solar energy is that the energy is free, non-polluting. The study reported here was designed to help supply the informations for the development of simple and relatively inexpensive solar warehouse for farm crop drying and storage. Specifically, the objectives of this study were to determine the performance of the solar collector fabricated, to compare solar supplemented heat drying with natural air drying and to develop a simulation model of temperature in stored grain, which can be used to study the effects due to changes in ambient air temperature. For those above objectives, solar collector was fabricated from available materials. Corrugated steel galvanized sheet, painted flat black, was used as absorbers and clear 0.2mm polyethylene sheet was the cover material. The warehouse for rough rice drying and storage was constructed with concrete block, and the solar collector was used as the roof of warehouse instead of original roofing system of it. The results obtained in this study were as follows: 1. The thermal efficiency of the solar collector was average 26 percent and the overall heat transfer coefficient of the collector was approximately $25kJ/hr.m^2\;^{\circ}K$. 2. Solar heated air was sufficient to dry one cubic meter of rough rice from 23.5 to 15.0 percent in 7 days and natural air was able to dry the same amount of rough rice from 20.0 to 5 percent in l2 days. 3. Drying with solar heat reduced the required drying time to dry the same amount of rough rice into a half compared to natural air drying, but overdrying problems of the bottom layer were so severe that these problems should be thoroughly analyzed. 4. Simulation model of temperature in stored grain was developed and the results of predicted temperature agreed well with test results. 5. Based on those simulated temperature, changes in the grain-temperature were a large at the points of the wallside and the damage of the grain would be severe at the contact area of wall.

• Korean Journal of Poultry Science
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• v.41 no.2
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• pp.135-142
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• 2014

This study was conducted to evaluate dietary effects of Marigold extract on laying performance, egg quality, oxidative stability of egg yolk and lutein transfer into chicken eggs. A total of one-hundred eighty nine 55-wk-old Hy-Line Brown layers were divided into seven groups and fed control diet or each experimental diet containing 0.1, 0.3, 0.5, 1.0, 1.5 or 2.0% Marigold extract. Egg production, egg weight and daily egg mass were not affected by dietary treatments. The yolk colors in groups fed diets containing Marigold extract were significantly higher than that of control. The Haugh unit were tended to be improved by feeding of diets containing Marigold extract although there were no significant difference in egg shell strength and thickness. The MDA (malondialdehyde) contents in groups fed diets containing Marigold extract above 0.5% were significantly reduced than that of control. After 14d of storage, the Haugh unit values in groups feed diets containing 0.3 and 1.0% Marigold extract were significantly higher than that of control (p<0.05). The concentration of lutein in egg yolk increased by feeding of Marigold extract. When 2% Marigold extract was supplemented to the diet, lutein content of egg was increased as much as 1.71 mg/60 g. These results indicated that the use of Marigold extract in layer diets was effective in egg quality and for the production of lutein fortified eggs.

• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.875-886
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• 2015

The upland soils (56 samples) from organic farms in Gyeonggi-do (12 sites), Gangwon-do (8 sites), Chungcheong-do (14 sites), Gyeongsang-do (4 sites), Jeollado (18 sites) in Korea were collected and their physical and chemical properties were analyzed by RDA's methods. In the results of physical property, the bulk density of soils averaged $1.14Mgm^{-3}$ (surface soil), $1.38Mgm^{-3}$ (subsoil), respectively. The porosity of them was 57%, 48%. Organically managed soil's (OS) bulk density was lower than conventional soil's but OS's porosity was a little higher than conventionally managed soil in surface soil. The depth of plough layer in organically managed soils was 21.2 cm indicating that the organic farming had good effect on soil physical property. In the results of chemical property, the surface soil pH was 6.9 and the contents of organic matter (OM) was $26gkg^{-1}$, available phosphate (Avail. $P_2O_5$) was $554mgkg^{-1}$, exchangeable calcium (Exch. Ca) was $8.9cmol_ckg^{-1}$, exchangeable potassium (Exch. K) was $0.89cmol_ckg^{-1}$, exchangeable magnesium (Exch. Mg) was $2.0cmol_ckg^{-1}$. The subsoil pH was 6.8 and the contents of OM was $21gkg^{-1}$, avail. $P_2O_5$ was $491mgkg^{-1}$, exch. Ca was $7.9cmol_ckg^{-1}$, exch. K was $0.68cmol_ckg^{-1}$, exch. Mg was $1.8cmol_ckg^{-1}$. The nutrient accumulation emerged in organic farming. Compared to the optimum nutrient range for the conventional upland soils, the exceed rate of pH, OM, available phosphate, and exchangeable Ca, K, and Mg was 79, 52, 64, 84, 66% and 55%, respectively, which mainly resulted from the over-application of lime materials or livestock manure compost. With these results it is suggested that organic farm need to reduce the use of inputs, which make soil alkalification or nutrient accumulation. More study on effects of inputs on lowering soil pH from alkalification could help organically managed soil to be improved.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.547-553
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• 2017

In the current medical field, lead is widely used as a radiation shield. However, the lead weight is very heavy, so wearing protective clothing such as apron is difficult to wear for long periods of time and there is a problem with the danger of lethal toxicity in humans. Recently, many studies have been conducted to develop substitute materials of lead to resolve these problems. As a substitute materials for lead, barium(Ba) and iodine(I) have excellent shielding ability. But, It has characteristics emitting characteristic X-rays from the energy area near 30 keV. For patients or radiation workers, shielding materials is often made into contact with the human body. Therefore, the characteristic X-rays generated by the shielding material are directly exposured in the human body, which increases the risk of increasing radiation absorbed dose. In this study, we have developed the FLUKA transport code, one of the most suitable elements of radiation transport codes, to remove the characteristic X-rays generated by barium or iodine. We have verified the reliability of the shielding fraction of the structure of the structure shielding by comparing with the MCPDX simulations conducted as a prior study. Using the MCNPX and FLUKA, the double layer shielding structures with the various thickness combination consisting of barium sulphate ($BaSO_4$) and bismuth oxide($Bi_2O_3$) are designed. The accuracy of the type shown in IEC 61331-1 was geometrically identical to the simulation. In addition, the transmission spectrum and absorbed dose of the shielding material for the successive x-rays of 120 kVp spectra were compared with lead. In results, $0.3mm-BaSO_4/0.3mm-Bi_2O_3$ and $0.1mm-BaSO_4/0.5mm-Bi_2O_3$ structures have been absorbed in both 33 keV and 37 keV characteristic X-rays. In addition, for high-energy X-rays greater than 90 keV, the shielding efficiency was shown close to lead. Also, the transport code of the FLUKA's photon transport code was showed cut-off on low-energy X-rays(below 33keV) and is limited to computerized X-rays of the low-energy X-rays. But, In high-energy areas above 40 keV, the relative error with MCNPX was found to be highly reliable within 6 %.

• Journal of Veterinary Clinics
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• v.11 no.1
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• pp.485-505
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• 1994

Lead toxicity was evaluated in forty-five cats on a balanced diet, treated with 0(control), 10, 100(low), 1, 000, 2, 000 and 4, 000(high)ppm of lead acetate orally on a body weight basis. The objectives were to describe the gross and histopathologic changes and to demonstrate what tissue lead concentrations correlate with the known dosages of lead. In subclinical lead toxicity, greater than 80% of the absorbed lead was deposited in the bone, whereas in more acute lead toxicity, 42% of absorbed lead was deposited in the bone and 36% and 20% of absorbed lead was deposited in the kidneys and in the liver, respectively. No gross lesions were found in the nervous system. Yellow-brown colored livers appear to be associated with lead toxicity. Neuronal necrosis in the cerebrum was the most predominant histopathologic finding. Astrocytic proliferation in the cerebral gray matter was observed in 1 high dose cat. Gliosis was noted in the cerebral cortex of 6 high dose cats. Two high dose cats had demyelination in the deepest layer of the cortical gray matter of the cerebrum. Extravasation of red cells and cavitation around the vessels were found in the cerebrum of 1 high dose cat. Six high dose cats had degeneration of Purkinje cells in the cerebellum. The microscopic findings in the peripheral nerves were ambiguous. In more acute toxicity, the cats had lead inclusions in the epithelial cells of proximal tubules of the kidneys of 7 cats and hepatocytes of the liver of S cats. These inclusions could be seen wlth H&E, but were more prominent with orcein staining. Two high dose cats had granulomas and connective tissue hyperplasia between tubules of the kidneys. Periportal hepatocyte vacuolization was observed in the liver of 22 cats. Vacuolization of seminiferous tubules and a reduced number of spermatogonia(indicative of reduced spermatogenesis) were found in the testis of 5 treated cats. Cystic ovaries were observed in 3 high dose cats and poor development of oogonia was found in 2 cats. The diagnosis of lead toxicity in cats can be suspected on the basis of the histopathologic lesions described, and can be of value in contributing to a diagnosis. A reliable diagnosis of lead poisoning can be helped utilizing tissue lead analysis(post molten)