• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.1
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• pp.25-40
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• 2004

The supersonic shock wave generated by fully coupled explosion will change into subsonic shock wave, plastic wave, and elastic wave consecutively as the wave propagates through rock mass. While the estimation of the blast-induced peak pressure was the main aim of the companion paper, this paper will concentrate on the estimation of the rise time of blast-induced pressure. The rise time can be expressed as a function of explosive density, isentropic exponent, detonation velocity, exponential coefficient of the peak pressure attenuation, dynamic yield stress, plastic wave velocity, elastic wave velocity, rock density, Hugoniot parameters, etc. Parametric analysis was performed to pinpoint the most influential parameter that affects the rise time and it was found that rock properties are more sensitive than explosive properties. The probabilistic distribution of the rise time is evaluated by the Rosenblueth'S point estimate method from the probabilistic distributions of explosive properties and rock properties. Numerical analysis was performed to figure out the effect of rock properties and explosive properties on the uncertainty of blast-induced vibration. Uncertainty analysis showed that uncertainty of rock properties constitutes the main portion of blast-induced vibration uncertainty rather than that of explosive properties. Numerical analysis also showed that the loading rate, which is the ratio of the peak blasting pressure to the rise time, is the main influential factor on blast-induced vibration. The loading rate is again more influenced by rock properties than by explosive properties.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.3
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• pp.393-401
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• 2015

In the construction of a TBM tunnel, it is very important to acquire accurate information of the excavated rock mass for an efficient and safe work. In this study, we developed the prediction system of TBM tunnel face ahead using probe drilling equipment and drilled hole imaging equipment to predict rock mass conditions of the tunnel face ahead. The prediction system consists of the probe drilling equipment, drilled hole imaging equipment and analysis software. The probe drilling equipment has been developed to be applicable to both non-coring and coring. Also the probe drilling equipment can obtain the drilling parameters such as feed pressure, torque pressure, rotation speed, drilling speed and so on. The drilling index is converted to the drilling index RMR through the correlation between a drilling index and core RMR. The developed system verification was carried out through a slope and tunnel field application. From the field application result, the non-coring is four times faster than a coring and the drilling index RMR and core RMR are similar in the distribution range. This system is expected to predict the rock mass conditions of the TBM tunnel face ahead very quickly and efficiently.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.6
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• pp.585-597
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• 2013

In this study, in order to evaluate stability of the room-and-pillar underground structure, a series of preliminary numerical analyses were performed. Design concept and procedure of an underground structure for obtaining a space are proposed, which should be different from structural design for the room-and-pillar in mine. With assumed material properties, a series of numerical analyses were performed by varying size ratios of room and pillar and then the failure modes and location at yielding initiation were investigated. From the results, relationship between the ratio of pillar width to the roof span (w/s) and overburden pressure at failure initiation shows a relatively linear relation, and the effect of w/s on structural stability is much more critical than the ratio of pillar width and height (w/H) which is a crucial parameter in design of the room-and-pillar mining. It means that roof tensile failure and shear failure at shoulder and pillar are necessary to be considered together for confirming overall structural stability of the room-and-pillar structure, rather than considering the pillar stability only in mining. Failure modes and location at failure initiation were varied with respect to the ratio of room and pillar widths. Therefore, it is necessary to simultaneously consider stability of both roof span and pillar for design of underground structure by the room-and-pillar method.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.3
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• pp.271-287
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• 2013

In this study, more convenient model(S-model) for predicting ground surface settlement is developed through comparing field monitoring data of the domestic subway applied shield TBM method with conventional equation & numerical analysis. Sample stations are chosen from whole of excavation section and lateral & vertical ground surface settlement characteristic with excavation are analysed. Based on analysis result, through the comparison with actual monitoring data, the model that is possible to compute maximum surface settlement and settlement influence area is suggested with assumption that lateral surface settlement forms are composed relaxed zone and elastic zone. In addition, vertical ground surface settlement patterns with excavation are similar to cubic-function and S-model with assumption that coefficients are function of tunnel diameter and depth is suggested. Consequently, the ground surface settlement patterns are significantly similar to actual monitoring data and numerical method result. Thus, as a result, when tunnels are excavated using sheild TBM through rather soft weathered soil & rock layer, prediction of ground surface settlement with excavation using convenient S-model is practicable.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.10
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• pp.1395-1403
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• 2008

The objective of the present study was to estimate genetic parameters for economic traits in Markhoz goats. Data collected from 1993 to 2006 by the Markhoz goat Performance Testing Station in Sanandaj, Iran, were analyzed. The traits recorded as body weight performance at birth (BW), weaning (WW), six month (6MW), nine month (9MW), yearling (YW) and yearling fleece weight (YFW) were investigated. Least square analyses were used for estimation of environmental effects. Genetic parameters were estimated with single and multi trait analysis using restricted maximum likelihood (REML) procedures, under animal models. By ignoring or including maternal additive genetic effects and maternal permanent environmental effects, five different models were fitted for each trait. The effects of sex, type of birth, age of dam and year of birth on the all body weights were significant (p<0.01), but had no effects on YFW except year of birth. Age of kids had significant influences on WW and 6MW (p<0.01). A log likelihood ratio test was carried out for choosing the most suitable model for each trait. Total heritability estimates for YFW and growth traits varied from 0.16 for YFW and WW to 0.41 for YW. For all traits, maternal heritability was lower than direct heritability, ranging from 0.06 for BW to 0.01 for 6MW and 9MW. The magnitude of $c^2$ was more substantial for BW than the others, and relative importance was reduced from 0.12 for BW to 0.04 for 9MW. The direct additive genetic correlations estimates were positive and varied from 0.21 between BW-YW to 0.96 between WW-6MW. Direct additive genetic correlations between YFW and body weight traits were positive and ranged from 0.14 between BW-YFW to 0.67 between 6MW-YFW. For all traits, the corresponding estimates for phenotypic correlation were positive and lower than genetic correlations. The maternal additive genetic correlations between various traits were varied and ranged from -0.19 between 9MW-YFW to 0.96 between 6MW-9MW. The estimates of the maternal permanent environmental correlations between various traits were positive and ranged from 0.33 between WW-YFW to 0.93 between WW-6MW. Also, the environmental correlations between various traits ranged from 0.01 between BW-YFW and WW-YFW to 0.70 between 9MW-YW. Estimates of genetic parameters for various traits in this study confirm that selection should be applied on WW for genetic improvement in Markhoz goats.

• The Journal of the Korea Contents Association
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• v.13 no.6
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• pp.212-226
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• 2013

In this paper, I tried to analyze objectively the structural relation among market directivity, study directivity, and achievement of organization which are intended to equip competitive power of social welfare organization on the social service market centrally formed by the voucher business. Data collection objectives is consist of 7 metropolitan cities social welfare organizations, performing voucher businesses of the Ministry of Health and Welfare, and data is secured from 203 institutions. Some basic technological statistics and regression analysis employing structural equation was used for analysing data. Analyzed result, the structural relation among market directivity and study directivity and organizational performance is appeared meaningfully according to the fact that goodness of fit coefficients is TLI = .86, CFI = .89, RMSEA = .02. With respect to achievement of organization, market directivity and study directivity are all confirmed as positively influenced. The results of analysis about whether market directivity and study directivity for achievement of organization is direct effect or indirect effect shows that market directivity and study directivity are all influenced both directly to organizational performance, and as parameter. By the results of this research, social welfare organizations performing voucher business are to have practical implication requiring organization learning needed collecting and sharing the relevant information and organizational response toward voucher social service market.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.1
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• pp.54-60
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• 2006

[ $MnO_2$ ]-Coated Sand(MCS) was prepared with variation of coating temperature, coating time, and dosage of initial Fe(III) with two kinds of sands such as Joomoonjin and quartz sand. An optimum condition for the preparation MCS was determined from the coating efficiency as well as the oxidation efficiency of As(III). Coating efficiency of Mn was strongly dependent on the coating temperature but quite similar over the investigated coating time, showing an increased coating efficiency at higher coating temperature. In contrast to coating efficiency, the oxidation efficiency of As(III) by MCS was severely reduced as increase of coaling temperature. By considering these results, an optimum coating temperature and time for the preparation of MCS was selected as $150^{\circ}C$ and 1-hr, respectively. Coating efficiency increased as the dosage of initial Mn(II) increased, while As(III) oxidation was maximum at 0.8 Mn(II) mol/kg sand. The solution pH was identified as an important parameter affecting stability of MCS, and dissolution of Mn from MCS increased as pH decreased. Oxidation rate of As(III) increased as the dosage of MCS increased as well as solution pH decreased.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.9
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• pp.623-629
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• 2011

The adsorption characteristics of tricyclazole by granular activated carbon were experimently investigated in the batch adsorption. Kinetic studies of adsorption of tricyclazole were carried out at 298, 308 and 318 K, using aqueous solutions with 250, 500 and 1,000 mg/L initial concentration of tricyclazole. It was established that the adsorption equilibrium of tricyclazole on granular activated carbon was successfully fitted by Freundlich isotherm equation at 298 K. The pseudo first order and pseudo second order models were used to evaluate the kinetic data and the pseudo second order kinetic model was the best with good correlation. Values of the rate constant ($k_2$) have been calculated as 0.1076, 0.0531, and 0.0309 g/mg h at 250, 500 and 1,000 mg/L initial concentration of tricyclazole, respectively. Thermodynamic parameter such as activation energy, standard enthalpy, standard entropy and standard free energy were evaluated. The positive value for enthalpy, -66.43 kJ/mol indicated that adsorption interaction of tricyclazole on activated carbon was an exothermic process. The estimated values for standard free energy were -5.08~-8.10 kJ/mol over activated carbon at 200 mg/L, indicated toward a exothermic process.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.4
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• pp.279-287
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• 2010

To identify characteristics of the water quality at Goseong bay, we analyzed long term monitoring data collected at surface and bottom water which was accumulated during the period of 1987~2009. The result showed that the waters of Goseong bay represented mesotrophic level that is based on chlorophyll-a, DIP and DIN and seasonal average of COD that indicates level by the COD criteria. This analysis can be translated that the waters is comparatively clean even though the waters is in the closed bay that slowly diffuses influx mass. We also did the time series analysis, correlation analysis and regression analysis on the moving average of the water parameter at Goseong bay. According to the results, DIP showed a increasing trend as time passed while DIN was on a decreasing trend under the same condition. In the waters of Goseong bay, the phyto-plankton growth was shown to be limited by DIN concentration. The chlrophyll-a was at the peak in August, at $4.60{\mu}g/L$. As the seasonal average and index were the highest in November, it was understood that the balance of nutrient at Goseong bay was dependent more on inner factors, ie, mass farming of aquatic species and release of bottom sediment rather than on inflow of fresh water. Accordingly, it is needed to consider the balance of nutrient like DIP and DIN to manage the water quality or estuaries at Goseong bay.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.3
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• pp.160-163
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• 2008

$CO_2$ ocean sequestration is being considered as a way to earn a frame of time to change other industrial life pattern to overcome the global warming crisis. The method is to dilute the captured $CO_2$ into ocean by ejecting the liquefied $CO_2$ through nozzles. The main issue of such method is the effectiveness and safety, and in both problems the rising speed of those LCO2 droplet is the key parameter. In this paper, the rising speed of LCO2 droplets is numerically studied including the effect of the surfactant which can be residing along the density interface of the droplets. A front tracking method with a simple surface tension model is developed and the rising speed of the droplets is carefully investigated with varying the various parameters. It is demonstrated that the variable surface tension can change the deformation of the droplet, the flow near the interface, and the rising speed.