• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.338-344
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• 1995

The wet ash method has been used as an official standard procedure for the analysis of Cd in brown rice in Korea, but this method involves several disadvantages. Thus, four analytical methods were compared in this experiment in order to find a more efficient method for the Cd analysis in brown rice. Evaluation was made based on both the Cd recovery percentages from the Cd-spiked samples and the relationships between Cd contents obtained by the official procedure and other methods. Results showed that ashing 50g brown rice at $600^{\circ}C$(dry ash method) recovered nearly 80% of the spiked Cd. This recovery percentage was a little lower than that of the wet ash method(87%) but higher than those of other methods. The dry ash method had the lowest standard deviations and revealed the highest correlation coefficient($r=0.98^{\ast\ast}$) in Cd contents with the standard wet ash method. These results demonstrated that the dry ash method, ashing 50g brown rice at $600^{\circ}C$, would be as efficient as the wet ash method and could be employed as a recommended procedure for the Cd analysis of brown rice.

• Computers and Concrete
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• v.17 no.1
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• pp.29-51
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• 2016

Tension-stiffening is the contribution of concrete between the cracks to carry tensile stresses after cracking in Reinforced Concrete (RC) members. In this paper, a tension-stiffening model has been proposed for computationally efficient nonlinear analysis of RC flexural members subjected to service load. The proposed model has been embedded in a typical cracked span length beam element. The element is visualized to consist of at the most five zones (cracked or uncracked). Closed form expressions for flexibility and stiffness coefficients and end displacements have been obtained for the cracked span length beam element. Further, for use in everyday design, a hybrid analytical-numerical procedure has been developed for nonlinear analysis of RC flexural members using the proposed tension-stiffening model. The procedure yields deflections as well as redistributed bending moments. The proposed model (and developed procedure) has been validated by the comparison with experimental results reported elsewhere and also by comparison with the Finite Element Method (FEM) results. The procedure would lead to drastic reduction in computational time in case of large RC structures.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.2
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• pp.55-62
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• 2013

An analytical procedure to determine a proper profile of the spring rail that generates intended contact pressure distribution in the flat wiper blade is introduced. The flat wiper blade is one piece blade and subjected to pressing force at a center point. In this type of blade, contact pressure distribution in the tip of rubber strip is determined by the pressing force, the initial profile of the blade before contact and bending stiffness of the blade. Experimentally obtained bending stiffness of the blade assembly is almost identical to that of the spring rail. Principle of reciprocity has been used to define the initial profile of spring rail from the deformed profile that is assumed to be identical to the windshield glass profile. The procedure has been verified experimentally by measuring the contact pressure of the blade assembled with the spring rail designed by the procedure proposed here. Measured contact pressure distributions of the blades show good agreements with intended distributions over the entire blade span. Consequently, it can be concluded that proposed procedure has relatively good accuracy in developing the spring rail for flat blade having a specific contact pressure distribution.

• Nuclear Engineering and Technology
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• v.43 no.6
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• pp.573-582
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• 2011

The in-cabinet response spectrum is used to define the input motion in the seismic qualification of instruments and devices mounted inside an electrical cabinet. This paper presents a procedure for generating the in-cabinet response spectrum for electrical equipment based on in-situ testing by an impact hammer. The proposed procedure includes an algorithm to build the relationship between the impact forces and the measured acceleration responses of cabinet structures by estimating the state-space model. This model is used to predict seismic responses to the equivalent earthquake forces. Three types of structural model are analyzed for numerical verification of the proposed method. A comparison of predicted and simulated response spectra shows good convergence, demonstrating the potential of the proposed method to predict the response spectra for real cabinet structures using vibration tests. The presented procedure eliminates the uncertainty associated with constructing an analytical model of the electrical cabinet, which has complex mass distribution and stiffness.

• Journal of Ginseng Research
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• v.37 no.4
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• pp.475-482
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• 2013

The main active components of Panax ginseng are ginsenosides. Ginsenoside Rb1 and Rg1 are accepted as marker substances for quality control worldwide. The analytical methods currently used to detect these two compounds unfairly penalize steamed and dried (red) P. ginseng preparations, because it has a lower content of those ginsenosides than white ginseng. To manufacture red ginseng products from fresh ginseng, the ginseng roots are exposed to high temperatures for many hours. This heating process converts the naturally occurring ginsenoside Rb1 and Rg1 into artifact ginsenosides such as ginsenoside Rg3, Rg5, Rh1, and Rh2, among others. This study highlights the absurdity of the current analytical practice by investigating the time-dependent changes in the crude saponin and the major natural and artifact ginsenosides contents during simmering. The results lead us to recommend (20S)- and (20R)-ginsenoside Rg3 as new reference materials to complement the current P. ginseng preparation reference materials ginsenoside Rb1 and Rg1. An attempt has also been made to establish validated qualitative and quantitative analytical procedures for these four compounds that meet International Conference of Harmonization (ICH) guidelines for specificity, linearity, range, accuracy, precision, detection limit, quantitation limit, robustness and system suitability. Based on these results, we suggest a validated analytical procedure which conforms to ICH guidelines and equally values the contents of ginsenosides in white and red ginseng preparations.

• Structural Engineering and Mechanics
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• v.78 no.4
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• pp.485-496
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• 2021

So far analytical methods on collapse assessment of three-dimensional (3-D) steel frames have mainly focused on a single-column-removal scenario. However, the collapse of the Federal Building in the US due to car bomb explosion indicated that the loss of multiple columns may occur in the real structures, wherein the structures are more vulnerable to collapse. Meanwhile, the General Services Administration (GSA) in the US suggested that the removal of side columns of the structure has a great possibility to cause collapse. Therefore, this paper analytically deals with the robustness of 3-D steel frames in a two-side-column-removal (TSCR) scenario. Analytical method is first proposed to determine the collapse resistance of the frame during this column-removal procedure. The reliability of the analytical method is verified by the finite element results. Moreover, a design-based methodology is proposed to quickly assess the robustness of the frame due to a TSCR scenario. It is found the analytical method can reasonably predict the resistance-displacement relationship of the frame in the TSCR scenario, with an error generally less than 10%. The parametric numerical analyses suggest that the slab thickness mainly affects the plastic bearing capacity of the frame. The rebar diameter mainly affects the capacity of the frame at large displacement. However, the steel beam section height affects both the plastic and ultimate bearing capacity of the frame. A case study on a six-storey steel frame shows that the design-based methodology provides a conservative prediction on the robustness of the frame.

• Computers and Concrete
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• v.31 no.4
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• pp.349-358
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• 2023

This paper describes an in-depth analysis on flexural strength of a girder-deck system experiencing a strand debonding damage with various strengthening systems, based on finite element software ABAQUS. A detailed finite element analysis (FEA) model was developed and verified against the relevant experimental data performed by other researchers. The proposed analytical model showed a good agreement with experimental data. Based on the verified FE model, over a hundred girder-deck systems were investigated with the consideration of following variables: 1) debonding level, 2) span-to-depth ratio (L/d), 3) strengthening type, 4) strengthening material thickness. Based on the data above, a new detailed analytical model was developed and proposed for estimating residual flexural strength of the strand-debonding damaged girder-deck system with strengthening systems. It was demonstrated that both finite element model and analysis model could be used to predict flexural behaviors for debonding damaged prestressed girder-deck systems. Since the strands are debonding from surrounding concrete over a certain zone over the length of the beam, the increase of strain in strands can be linked with a ratio ψ, which is L_p/c. The analytical model was proposed and developed regarding the ratio ψ. By conducting procedure of calculating ψ, the ψ value varies from 9.3 to 70.1. Multiple nonlinear regression analysis was performed in Software IBM SPSS Statistics 27.0.1 to derive equation of ψ. ψ equation was curved to be an exponential function, and the independent variable (X) is a linear function in terms of three variables of debonding level (λ), span length (L), and amount of strengthening material (A_s). The coefficient of determinate (R²) for curve fitting in nonlinear regression analysis is 0.8768. The developed analytical model was compared to the ultimate capacities computed by FEA model.

• Analytical Science and Technology
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• v.21 no.3
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• pp.174-182
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• 2008

The study on the development of rapid analytical method of PCBs containing waste was performed by considering the extraction, column cleanup process, analytical condition and so on. In the established method, new sample clean-up procedure, new quantification peaks and temperature program were introduced. Method detection limit of the method was 0.5 mg/L, and the method could save the total run time to 2/3, therefore save the analysis cost, The new rapid analytical method of transformer oil was suggested to the waste official test method.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.5
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• pp.19-28
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• 2014

Given the structure of Korean mountains, it is more appropriate to apply the relative elevation method than the absolute elevation method. However, so far there were not suitable quantitative methodologies to analyze relative elevation, these analytical concepts were difficult to be utilized in urban environmental planning. This study suggested three methods for analyzing relative elevation, and one method for setting the analytical scope of relative elevation by calculating terrain relief. The results showed that the procedure considering 500m radius of each point and standardizing to 30% of the 7th height ridge was the most effective method to extract the local topography. This methodology is the quantitative tool to be able to conserve local important hills and ridges, and apply to fields of urban environmental planning and ecological restoration, especially urban ecological network.

• Structural Engineering and Mechanics
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• v.7 no.2
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• pp.159-180
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• 1999

The present paper shows a new non-tensorial approach to derive basic equations for various structural analyses. It can be used directly in numerical computation procedures. The aim of the paper is, however, to show that the approach serves as an excellent tool for analytical purposes also, working as a link between analytical and numerical techniques. The paper gives a method to derive, at first, expressions for strains in general beam and shell analyses, and secondly, the governing equilibrium equations. The approach is based on the utilization of local fixed Cartesian coordinate systems. Applying these, all the definitions required are the simple basic ones, well-known from the analyses in common global coordinates. In addition, the familiar principle of virtual work has been adopted. The method will be, apparently, most powerful in teaching the theories of curved beam and shell structures for students not familiar with tensor analysis. The final results obtained have no novelty value in themselves, but the procedure developed opens through its systematic and graphic progress a new standpoint to theoretical considerations.