• Journal of Biosystems Engineering
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• v.3 no.2
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• pp.35-61
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• 1978

To find out the power tiller's travel and tractive characteristics on the general slope land, the tractive p:nver transmitting system was divided into the internal an,~ external power transmission systems. The performance of power tiller's engine which is the initial unit of internal transmission system was tested. In addition, the mathematical model for the tractive force of driving wheel which is the initial unit of external transmission system, was derived by energy and force balance. An analytical solution of performed for tractive forces was determined by use of the model through the digital computer programme. To justify the reliability of the theoretical value, the draft force was measured by the strain gauge system on the general slope land and compared with theoretical values. The results of the analytical and experimental performance of power tiller on the field may be summarized as follows; (1) The mathematical equation of rolIing resistance was derived as $$Rh=\frac {W_z-AC \[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\] sin\theta_1}} {tan\phi \[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]+\frac{tan\theta_1}{1}$$ and angle of rolling resistance as $$\theta _1 - tan^1\[ \frac {2T(AcrS_0 - T)+\sqrt (T-AcrS_0)^2(2T)^2-4(T^2-W_2^2r^2)\times (T-AcrS_0)^2 W_z^2r^2S_0^2tan^2\phi} {2(T^2-W_z^2r^2)S_0tan\phi}\] $$and the equation of frft force was derived as$$P=(AC+Rtan\phi)\[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]cos\phi_1 \ulcorner \frac {W_z \ulcorner{AC\[ [1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]sin\phi_1 {tan\phi[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\]+ \frac {tan\phi_1} { 1} \ulcorner W_1sin\alpha $$The slip coefficient K in these equations was fitted to approximately 1. 5 on the level lands and 2 on the slope land. (2) The coefficient of rolling resistance Rn was increased with increasing slip percent 5 and did not influenced by the angle of slope land. The angle of rolling resistance Ol was increasing sinkage Z of driving wheel. The value of Ol was found to be within the limits of Ol =2\ulcorner "'16\ulcorner. (3) The vertical weight transfered to power tiller on general slope land can be estim ated by use of th~ derived equation: $$R_pz= \frac {\sum_{i=1}^{4}{W_i}} {l_T} { (l_T-l) cos\alpha cos\beta \ulcorner \bar(h) sin \alpha - W_1 cos\alpha cos\beta$$The vertical transfer weight $R_pz$ was decreased with increasing the angle of slope land. The ratio of weight difference of right and left driving wheel on slop eland,$\lambda= \frac { {W_L_Z} - {W_R_Z}} {W_Z} $, was increased from ,$\lambda$=0 to$\lambda$=0.4 with increasing the angle of side slope land ($\beta = 0^\circ~20^\circ) (4) In case of no draft resistance, the difference between the travelling velocities on the level and the slope land was very small to give 0.5m/sec, in which the travelling velocity on the general slope land was decreased in curvilinear trend as the draft load increased. The decreasing rate of travelling velocity by the increase of side slope angle was less than that by the increase of hill slope angle a, (5) Rate of side slip by the side slope angle was defined as $ S_r=\frac {S_s}{l_s} \times$ 100( %), and the rate of side slip of the low travelling velocity was larger than that of the high travelling velocity. (6) Draft forces of power tiller did not affect by the angular velocity of driving wheel, and maximum draft coefficient occurred at slip percent of S=60% and the maximum draft power efficiency occurred at slip percent of S=30%. The maximum draft coefficient occurred at slip percent of S=60% on the side slope land, and the draft coefficent was nearly constant regardless of the side slope angle on the hill slope land. The maximum draft coefficient occurred at slip perecent of S=65% and it was decreased with increasing hill slope angle $\alpha$. The maximum draft power efficiency occurred at S=30 % on the general slope land. Therefore, it would be reasonable to have the draft operation at slip percent of S=30% on the general slope land. (7) The portions of the power supplied by the engine of the power tiller which were used as the source of draft power were 46.7% on the concrete road, 26.7% on the level land, and 13~20%; on the general slope land ($\alpha = O~ 15^\circ ,\beta = 0 ~ 10^\circ$) , respectively. Therefore, it may be desirable to develope the new mechanism of the external pO'wer transmitting system for the general slope land to improved its performance.l slope land to improved its performance.

• Journal of Biosystems Engineering
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• v.3 no.2
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• pp.34-34
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• 1978

To find out the power tiller's travel and tractive characteristics on the general slope land, the tractive p:nver transmitting system was divided into the internal an,~ external power transmission systems. The performance of power tiller's engine which is the initial unit of internal transmission system was tested. In addition, the mathematical model for the tractive force of driving wheel which is the initial unit of external transmission system, was derived by energy and force balance. An analytical solution of performed for tractive forces was determined by use of the model through the digital computer programme. To justify the reliability of the theoretical value, the draft force was measured by the strain gauge system on the general slope land and compared with theoretical values. The results of the analytical and experimental performance of power tiller on the field may be summarized as follows; (1) The mathematical equation of rolIing resistance was derived as $$Rh=\frac {W_z-AC \[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\] sin\theta_1}} {tan\phi \[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]+\frac{tan\theta_1}{1}$$ and angle of rolling resistance as $$\theta _1 - tan^1\[ \frac {2T(AcrS_0 - T)+\sqrt (T-AcrS_0)^2(2T)^2-4(T^2-W_2^2r^2)\times (T-AcrS_0)^2 W_z^2r^2S_0^2tan^2\phi} {2(T^2-W_z^2r^2)S_0tan\phi}\] $$and the equation of frft force was derived as$$P=(AC+Rtan\phi)\[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]cos\phi_1 ? \frac {W_z ?{AC\[ [1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]sin\phi_1 {tan\phi[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\]+ \frac {tan\phi_1} { 1} ? W_1sin\alpha $$The slip coefficient K in these equations was fitted to approximately 1. 5 on the level lands and 2 on the slope land. (2) The coefficient of rolling resistance Rn was increased with increasing slip percent 5 and did not influenced by the angle of slope land. The angle of rolling resistance Ol was increasing sinkage Z of driving wheel. The value of Ol was found to be within the limits of Ol =2? "'16?. (3) The vertical weight transfered to power tiller on general slope land can be estim ated by use of th~ derived equation: $$R_pz= \frac {\sum_{i=1}^{4}{W_i}} {l_T} { (l_T-l) cos\alpha cos\beta ? \bar(h) sin \alpha - W_1 cos\alpha cos\beta$$The vertical transfer weight $R_pz$ was decreased with increasing the angle of slope land. The ratio of weight difference of right and left driving wheel on slop eland,$\lambda= \frac { {W_L_Z} - {W_R_Z}} {W_Z} $, was increased from ,$\lambda$=0 to$\lambda$=0.4 with increasing the angle of side slope land ($\beta = 0^\circ~20^\circ) (4) In case of no draft resistance, the difference between the travelling velocities on the level and the slope land was very small to give 0.5m/sec, in which the travelling velocity on the general slope land was decreased in curvilinear trend as the draft load increased. The decreasing rate of travelling velocity by the increase of side slope angle was less than that by the increase of hill slope angle a, (5) Rate of side slip by the side slope angle was defined as $ S_r=\frac {S_s}{l_s} \times$ 100( %), and the rate of side slip of the low travelling velocity was larger than that of the high travelling velocity. (6) Draft forces of power tiller did not affect by the angular velocity of driving wheel, and maximum draft coefficient occurred at slip percent of S=60% and the maximum draft power efficiency occurred at slip percent of S=30%. The maximum draft coefficient occurred at slip percent of S=60% on the side slope land, and the draft coefficent was nearly constant regardless of the side slope angle on the hill slope land. The maximum draft coefficient occurred at slip perecent of S=65% and it was decreased with increasing hill slope angle $\alpha$. The maximum draft power efficiency occurred at S=30 % on the general slope land. Therefore, it would be reasonable to have the draft operation at slip percent of S=30% on the general slope land. (7) The portions of the power supplied by the engine of the power tiller which were used as the source of draft power were 46.7% on the concrete road, 26.7% on the level land, and 13~20%; on the general slope land ($\alpha = O~ 15^\circ ,\beta = 0 ~ 10^\circ$) , respectively. Therefore, it may be desirable to develope the new mechanism of the external pO'wer transmitting system for the general slope land to improved its performance.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.86-92
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• 2010

Thirty-one chicken feather-degrading bacteria were isolated from wasted feather, compost and wastewater in a chicken farm. These isolates were categorized as Firmicutes (21 strains), ${\gamma}$-proteobacteria (4 strains), Actinobacteria (4 strains), and Bacteroidetes (2 strains) by 16S rRNA gene sequence analysis. We examined the feather-degrading isolates for degradation in the 2% of chicken feather meal. The strain Chryseobacterium sp. FBF-7, Stenotrophomonas maltophilia FBS-4, and Lysinibacillus sp. FBW-3 were selected as a keratinolytic protein degrading bacteria which showed the highest feather degradation of 75-90%. The characteristics of amino acids extracted from chicken feather meal by using keratinolytic protein degrading isolates and chemical method with $Ca(OH)_2$ were analyzed. Total amino acid content of strain Chryseobacterium sp. FBF-7 was 1,661.6 ${\mu}mol$/ml, which was the highest and it was similar with chemical method. And essential amino acid content of total amino acid was thirty-seven percent (619.3 ${\mu}mol$/ml) and 596.9 ${\mu}mol$/ml for keratinolytic protein degrading isolates and chemical method, respectively. The major amino acids were valine, glutamic acid, aspartic acid, glycine, and proline by the strain Chryseobacterium sp. FBF-7 and especially, higher contents of aspartic acid, threonine, serine, cysteine, and tyrosine were detected compared with chemical method.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.330-336
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• 2011

Bacterial strains exhibiting fibrinolytic activity were screened from traditional Korean soybean sauce. The Fibrinolytic activities of the various isolated microorganism were further examined and the superior strain YJ11-21 was selected for further analyses. Gene sequence analysis of 16S rDNA of the YJ11-21 strain revealed Bacillus licheniformis. Optimal culture conditions were investigated in order to maximize the production of the fibrinolytic enzyme by YJ11-21. Amongst the carbon sources tested, glucose was the most effective for enzyme production and amongst the nitrogen sources tested, yeast extract was seen to be the most effective. A one percent addition of NaCl to the medium resulted in the highest fibrinolytic activity. Interestingly, a 10% addition of NaCl resulted in a high activity together with a high cell growth rate. Therefore, YJ11-21 is speculated of being a halotolerant. The optimum pH and temperature for enzyme production were a pH of 9.0 and $30^{\circ}C$, respectively.

• Korean Journal of Poultry Science
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• v.6 no.1
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• pp.12-23
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• 1979

This experiment was carrid out to investigate the interaction between boilelr strains and nutrition levels, and the performances of four broiler strains such as Han Hyup 603, Hubbard, Anak and Filch when they were fed by four different nutrition levels (High Protein and energy; HP. HE., Medium Protein and energy; MP. ME., Low Protein ana energy; LP. LE., and low protein and energy; LLP. LLE.). The data used in this study were obtained from a total of 1200 broiler type chicks in Poultry Testing Station, Korean Poultry Association from June 16, to August 11, 1978. Differences of all characters among four nutrition levels were significant except viability and carcass rate. HP. HE and MP. ME treatments showed nearly the same performances in body weight, feed efficiency and point, spread but they were significantly superior to those of LP. LE and LLP. LLE. There were not significant differences among four strains in feed efficiency and viability but other characters, body weight, point spread and carcass rate were observed that the performance of the best strain B was significantly superior to strain D but it was not recognized significance compared with strain A, C in tile result of statisticel analysis. In the interaction between strains and nutrition levels, body weight at high and levels showed significantly differences but at low and low nutrition levels were nearly same among four strains. Therefore this study demonstrated that comparision of body weights between strains should be performed at medium nutrition level or above. Also point spread calculated as index of body weight and feed efficiency was observed that strain B at low nutrition level is excellently higher than other strains and there were little differences at low nutrition level among all strains. It was found that ]it tie differences between performances of high arid medium levels seemed to be as the reason of high fat addition for energy source to high mutrition feed, and in general superior strain showed good performance at all the nutrition levels in$.$all characters but in body weight and point spread there were significantly different responses with different nutrition level, The most superior strain B among four strains earned the most profit per bird, Although performances of high and medium nutrition levels were nearly the same, medium nutrition level also showed the most profit because the feed cost of high nutrition level was higher than that of medium nutrition level.

• Microbiology and Biotechnology Letters
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• v.9 no.2
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• pp.83-89
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• 1981

Several kinds of organic acids, alcohols, aromatic compounds and sugars as carbon sources were tested in order to produce the cell mass of Rhizopus oryzae which is used in part of food processing or organic acid fermentation. Sodium acetate among them was good enough for carbon source as well as glucose under the concentration of one percent. All nitrogenous substances tested such as ammonium, nitrate or organic nitrogen compounds were well used by this strain of Rhizopus oryzae as nitrogen source. Ammonium sulfate among inorganic nitrogen compounds was most utilized as a nitrogen source in glucose or acetate medium. This strain did not require any growth factors such as yeast extract. The following composition of medium was therefore determined in order to produce the cell mass of Rhizopus oryzae: Na-acetate 1 %, (NH$_4$)$_2$SO$_4$ 0.2%, $K_2$HPO$_4$ 0.05%, MgSO$_4$.7$H_2O$ 0.01%, NaCl 0.01% (PH 5.5). The cell wall of mycelium grown in above medium was lysed optimally at pH 6.5 and 5$0^{\circ}C$ by the action of Strepzyme 115-5. On producing protoplast from mycelium by enzymatic action, almost all of the mycelium was damaged after 4hrs of treatment.

• Korean Journal of Agricultural Science
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• v.11 no.2
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• pp.322-327
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• 1984

As a basic studies for the laboratory scale production of alfalfa inoculum, Rhizobium meliloti M14 was characterized for its carbon and nitrogen sources, and some parameters for broth cultivation in a chemostat were studied by semi-continuous operation. The result s obtained were as follows. 1. Growth rate of the strain was increased by disaccharides than by monosaccharides tested, and pentoses resulted in poor growth than hexoses. Sugar alcohols including inositol supported the best growth among sugars. 2. Mannitol in the yeast-mannitol-broth was substituted by natural carbon sources such as malt extract or molasses. 3. Ten per cent of fresh yeast water appeared to supply enough amount of growth factor s for the strain, and the effect was equivalent to 0.24 percent of the commercial yeast extract powder. 4. Batch growth of the stain in a chemostat, New Brunswick Micro Ferm 28L, reached in the early stationary growth phase of $5{\sim}7{\times}10^9cells/ml$ after 36 hours of incubation. The culture at this stage was switched to semi-continuous cultivation, and the culture broth of four-fifth of the working volume was recovered every 24 hours when the maximal count was obtained.

• Journal of Life Science
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• v.21 no.7
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• pp.992-996
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• 2011

Endophytic fungi were isolated from the roots of plants growing naturally on the island of Dokdo. Plant samples, such as Miscanthus sinensis, Achyranthus japonica and Echinochloa crusgali were isolated from Dongdo, and those such as Honkenya peploides and Artemsia koidzumii were isolated from Seodo. Twenty one strains of endophytic fungi were isolated from these plants. To identify the strains, PCR (polymerase chain reaction) amplification of the partial ITS (Internal Transcribed Spacer) regions was done with universal primers ITS-1 and ITS-4 to determine the nucleotide sequence of the ITS regions. Of the strains isolated from Miscanthus sinensis, 75% were Penicillium sp. and 25% were Aspergillus sp. Fifty five percent of strains isolated from Achyranthus japonica were Penicillium sp., 30% were Aspergillus sp. and 15% were Zygorhynchus sp. Strains isolated from Echinochloa crusgali were Penicillium sp. (50%), Aspergillus sp. (12%), Giberella sp. (13%), Talaromyces sp. (9%) and Umbelopsis sp. (8%). Of the strains isolated from Honkenya peploides, 76% were Penicillium sp. and 24% were Pestalotiopsis sp. Strains isolated from Artemisia koidzumii were Penicillium sp. (81%) and Mucor sp. (19%). As a result of bioassay, Ec-3-1 strain isolated from Echinochloa crusgalli showed plant growth-promotion activity. Of all the endophytic fungi isolated, Penicillium sp. was the most abundantly distributed fungal strain in all plants used in this study.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.3
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• pp.57-67
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• 2021

A thorough administration of the arterial road network requires a continuous supply of updated and accurate information about the traffic that travels on the roads. One of the ways to effectively obtain the traffic volume and weight distribution of heavy vehicles is the BWIM technique, which is actively being studied. Unlike previous studies, this study was performed to develop a simplified Bridge Weigh-In-Motion (BWIM) algorithm that can easily estimate the axle spacing and weight of a traveling vehicle by utilizing the structural characteristics of the bridge. A short span RC T-beam bridge with no crossbeam installed was selected for the study, and then the strain response characteristics of bridge deck and girder was checked through preliminary field test. Based on the preliminary field test results, a simplified BWIM algorithm suitable for the bridge to be studied was derived. The validity and accuracy of the BWIM algorithm derived in this study were verified through field test. As a result of the verification test, the proposed BWIM algorithm can estimate the axle spacing and gross weight of the travelling vehicles with the average percent error of less than 3%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.1
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• pp.167-176
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• 1991

Finite element programs are developed, adopting the hyperbolic model and the Cam-clay model. In the hyperbolic model, a new model taking into account the volume change during shear is proposed and a new technique considering the density change underneath a footing is proposed. And a computing algorithm considered as more reasonable than existing one is presented. In the Cam-clay model, the deveoloped program is applied to sand, the case not recorded much, and then it is tried to analiza the behavior of sand from the viewpoint of the critical state concept. For this, the conventional CD triaxial compression tests and the footing model tests are carried out. The results are improved by 60 percent by using the modified hyperbolic model proposed. When the Cam-clay model is applied to sand, a model reflecting the overconsolidation effects and a computing algorithm accounting for the strain softening are needed. The results obtained by using the Cam-clay model are not much influenced by the value of the initial poisson's ratio, but those of the modified hyperbolic model are much influenced by that. So th values of the initial poisson's ratio must be selected deliberately in the numerical analysis.