• Journal of the Korean GEO-environmental Society
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• v.11 no.1
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• pp.19-26
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• 2010

The batch experiments and response surface methodology (RSM) have been applied to the investigation of the cadmium (Cd) adsorption by coal fly ash (CFA). CFA having maximum Cd removal mass of 8.51 mg/g were calculated from Langmuir model. Cd removal reaction with different initial pH ranged from 4 to 9. When the initial pH was higher, Cd was removed more by adsorption and precipitation. These results suggest that the lower pH cause an increase of $H^+$ ion concentration which competed with Cd ions for exchange sites in CFA. Also, The Cd adsorption was mathematically described as a function of parameters initial Cd concentration ($X_1$), initial pH ($X_2$), and initial CFA mass ($X_3$) being modeled by use of the Box-Behnken methods. Empirical models were developed to describe relationship between the experimental variables and response. Statistical analysis indicates that tree factors ($X_1$, $X_2$, and $X_3$) on the linear term (main effects), and tree factors ($X_1X_2$, $X_1X_3$, and $X_2X_3$) on the non-linear term (Interaction effect; cross-product) had significant effects, respectively. In this case, the value of the adjusted determination coefficient (adjusted $R^2=0.9280$) was closed to 1, showing a high significance of the model. Statistical results showed the order of Cd removal at experimental factors to be initial initial pH > initial Cd concentration > initial CFA mass.

• Bulletin of the Society of Naval Architects of Korea
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• v.24 no.3
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• pp.43-51
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• 1987

In this paper, dynamic elastic, plastic response of beam-columns is analysed using discrete models. composed of rigid bars and springs. The equation of motion is formulated including the shear deformation effect, and the stress change of yielding points is calculated with various yielding criteria. The effect of initial axial force is considered by two ways: (1) including the effect in interaction curve only. (2) including the effect directly in the equation of motion in terms of initial stiffness method is also used in nonlinear interaction procedure. It is found that this model is very effective in analysing not only the plastic response but the elastic response, and present method is more efficient than Finite Element Method from the viewpoint of calculation time and accuracy.

• The Journal of the Acoustical Society of Korea
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• v.16 no.5
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• pp.92-95
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• 1997

Thlephone pushbuttons simply consist of 0~9 digits, #, and ${\ast}$). So it is difficulty for user to input the various query command for information retrieval of audio response sevice. We suggest the new retrieval algorithm for audio response service using Korean initial sounds sequences. User those who do not know the retrieval code can retrieve the audio response service by pushing the telephone digit buttons which correspond to initial sounds of its name.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.68-76
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• 2021

As hazardous chemicals are releasing in process industries such as chemical & petro-chemical plants, the importance of initial responses has been always emphasized. However, little attention of quantitative analysis of the consequence by different initial responses during releasing of the chemicals has been done. The main objective of current paper is to investigate the effects of initial responses for the release accidents of hydrofluoric acid. For this, a simplified equation that can easily calculate the effect distance by varying concentrations of hydrofluoric acid was firstly deduced. In addition, a causal loops for the initial response steps using the system dynamics technique was constructed during release of 50% hydrofluoric acid. The effect distances according to different scenarios of the initial actions were also quantitatively analyzed by applying the simplified equation to the causal map. As a result, the highest reduction rate on the maximum effect distance was obtained with 'start time of action after leak detection' being about 87% while the lowest was 'arrival time of professional response team' being about 50%, as expected. It is expected that the results gained from the current study can be helpful as of basics of the initial response to the workplace, dealing with the hydrofluoric acid.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.50-59
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• 2021

Currently, the response correction factor is calculated by comparing the response measured by the load test on a bridge with the response analyzed in the initial analytical model. Then the load rating and the load carrying capacity are evaluated. However, the response correction factor gives a value that fluctuates depending on the measurement location and load condition. In particular, when the initial analytical model is not suitable for representing the behavior of a bridge, the range of variation is large and the analysis response by the calibrated model may give a result that is different from the measured response. In this study, a pseudo-static load test was applied to obtain static response with dynamic components removed under various load conditions of a vehicle moving at a low speed. Static response was measured on two similar PSC-I girder bridges, and the response correction factors for displacement and strain were calculated for each of the two bridges. When the initial analysis model was not properly set up, it is verified that the response of the analytical model corrected by the average response correction factor does not fall within the margin of error with the measured response.

• Steel and Composite Structures
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• v.30 no.5
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• pp.483-492
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• 2019

In the current study, the influence of the initial lateral (sweep) shape and the cross-sectional twist imperfection on the lateral torsional buckling (LTB) response of doubly-symmetric steel I-beams was investigated. The material imperfection (residual stress) was not considered. For this objective, standard European IPN 300 beam with different unbraced span was numerically analyzed for three imperfection cases: (i) no sweep and no twist (perfect); (ii) three different shapes of global sweep (half-sine, full-sine and full-parabola between the end supports); and (iii) the combination of three different sweeps with initial sinusoidal twist along the beam. The first comparison was done between the results of numerical analyses (FEM) and both a theoretical solution and the code lateral torsional buckling formulations (EC3 and AISC-LRFD). These results with no imperfection effects were then separately compared with three different shapes of global sweep and the presence of initial twist in these sweep shapes. Besides, the effects of the shapes of initial global sweep and the inclusion of sinusoidal twist on the critical buckling load of the beams were investigated to unveil which parameter was considerably effective on LTB response. The most compatible outcomes for the perfect beams was obtained from the AISC-LRFD formulation; however, the EC-3 formulation estimated the $P_{cr}$ load conservatively. The high difference from the EC-3 formulation was predicted to directly originate from the initial imperfection reduction factor and high safety factor in its formulation. Due to no consideration of geometric imperfection in the AISC-LFRD code solution and the theoretical formulation, the need to develop a practical imperfection reduction factor for AISC-LRFD and theoretical formulation was underlined. Initial imperfections were obtained to be more influential on the buckling load, as the unbraced length of a beam approached to the elastic limit unbraced length ($L_r$). Mode-compatible initial imperfection shapes should be taken into account in the design and analysis stages of the I-beam to properly estimate the geometric imperfection influence on the $P_{cr}$ load. Sweep and sweep-twist imperfections led to 10% and 15% decrease in the $P_{cr}$ load, respectively, thus; well-estimated sweep and twist imperfections should considered in the LTB of doubly-symmetric steel I-beams.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.625-628
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• 2008

The behavioral response of the individuals intimately involved with the initiation of the fire or those who aware of the initial fire cue, often appeared to be a determinant to the outcome of the fire incident, the nonadaptive flight or panic type behavioral response appears to be an infrequent, unusual or unique participant behavioral response in most fire incidents. Therefore, this study focused on the investigation of the individual behavioral responses depend on the distinction of sex and age.

• Coupled systems mechanics
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• v.6 no.4
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• pp.439-464
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• 2017

The hydro-elastic system consisting of a pre-stretched highly elastic plate, compressible Newtonian viscous fluid, and the rigid wall is considered and it is assumed that on the plate a lineal-located time-harmonic force acts. It is required to investigate the dynamic behavior of this system and determine how the problem parameters and especially the pre-straining of the plate acts on this behavior. The elasticity relations of the plate are described through the harmonic potential and linearized (with respect to perturbations caused by external time-harmonic force) form of these relations is used in the present investigation. The plane-strain state in the plate is considered and the motion of that is described within the scope of the three-dimensional linearized equations of elastic waves in elastic bodies with initial stresses. The motion of the fluid is described by the linearized Navier-Stokes equations and it is considered the plane-parallel flow of this fluid. The Fourier transform with respect to the space coordinate is applied for a solution to the corresponding boundary-value problem. Numerical results on the frequency response of the interface normal stress and normal velocity and the influence of the initial stretching of the plate on this response are presented and discussed. In particular, it is established that the initial stretching of the plate can decrease significantly the absolute values of the aforementioned quantities.

• Journal of KSNVE
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• v.6 no.6
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• pp.735-747
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• 1996

In this paper, buckling reliability analyses of stiffened cylinder with random initial geometric imperfection under axial impact load are performed by the combined response surface method. The effect of random geometric imperfection on the failure probability and reliability is recognized quantitatively. Buckling reliability decreases with the increase of mean value, cov of initial geometric imperfection under the same external load. Buckling probability under impact load is greater than those under static load with the same condition. From the probabilistic characteristics of imapct buckling load, relation between reliability index and safety parameter can be obtained in addition to the relation between load and reliability index. And those results can be used to determine the range of required safety parameter and acceptable imperfaction.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.27-32
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• 2003

Atmospheric and oceanic numerical models are usually initial-value and/or boundary-value problems. Change in either initial or boundary conditions leads to a variation of model solutions. Much of the predictability research has been done on the response of model behavior to an initial value perturbation. Less effort has been made on the response of model behavior to a boundary value perturbation. In this study, we use the latest version of the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM3) to study the model uncertainty to tiny SST errors. The results show the urgency to investigate the second kind predictability problem for the climate models.