• Earthquakes and Structures
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• v.9 no.2
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• pp.391-413
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• 2015

Damage of torsionally coupled buildings situated on soil sites has been reported in literature, however no site-specific studies are available for torsionally coupled buildings having site characteristics as a parameter. Effect of torsion is being accounted in seismic codes by the provision of design eccentricity where the dynamic to static eccentricity ratio is a parameter. In this paper, a methodology to determine dynamic to static eccentricity ratio of torsionally coupled buildings has been demonstrated for Delhi region for two torsionally coupled buildings on three soil sites. The variations of average and standard deviations of frame shears for stiff and flexible edges are studied for four eccentricity ratios for the two buildings for the three sites. From the limited studies made, it is observed that the dynamic to static eccentricity ratios observed for site-specific earthquakes are different from Indian seismic code specified value, hence a proposal is made to include a comment in Indian seismic code. Methodology proposed in this paper can be adopted for any region, for the estimation of dynamic to static eccentricity ratio for site specific earthquake.

• Computers and Concrete
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• v.10 no.3
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• pp.307-330
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• 2012

This work intends to contribute for the improvement of the procedure suggested by Brazilian Technical Code that takes into account the cracked concrete stiffness in the estimative of the displacement of reinforced concrete beams submitted to service loads. A damage constitutive model accounting for induced anisotropy, plastic deformations and bimodular elastic response is used in order to simulate the concrete behaviour, while an elastoplastic behaviour is admitted for the reinforcement. The constitutive models were implemented in a program for bars structures analysis with layered finite elements. Initially, the damage model is briefly presented as well as the parametric identification of the materials that have been used in the reinforced concrete beams. After that, beams with different geometries and reinforcement area are analyzed and a statistical method (ANOVA) is employed in order to identify the main variables in the problem. Soon after, the same procedure is used with another resistance of concrete, where the compression strength is changed. The numerical responses are compared with the ones obtained by Brazilian Technical Code and experimental tests in order to validate the use of the damage model. Finally, some remarks are discussed based on responses presented in this work.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.959-965
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• 2024

The High Temperature Test Unit (HTTU) was an experimental set-up to conduct separate and integral effects tests of the Pebble Bed Modular Reactor (PBMR) core. The annular core consisted of a randomly packed bed of uniform spheres. Natural convection tests using both nitrogen and helium, and forced convection tests using nitrogen, were conducted. The maximum material temperature achieved during forced convection testing was 1200 ℃. This paper presents the numerical analysis of the flow and temperature distribution for a forced convection test using 3D CFD as well as a 1D systems-CFD computer code. Several modelling approaches are possible, ranging from a fully explicit to a semi-implicit method that relies on correlations of their associated phenomena. For the comparison between codes, the analysis was performed using a porous media approach, where the conduction and radiative heat transfer were lumped together as an effective thermal conductivity and the convective heat transfer was correlated between the solid and gas phases. The results from both codes were validated against the experimental measurements. Favourable results were obtained, in particular by the systems-CFD code with minimal computational and time requirements.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2274-2281
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• 2024

RESRAD-ONSITE v7.2 code is used to assess the radiation effects on a farmer resident located in a hypothetical contaminated site planned for the first nuclear power plant project in Vietnam, namely Ninh Thuan 1, after decommissioning. Derived concentration guideline levels are preliminarily calculated for 17 radionuclides that are assumed to remain on a contaminated surface soil with an initial concentration of 1 pCi/g in the protected area of NPP site. For a reliable estimation, the site-specific conditions regarding the geological, hydrological, climate, and occupancy data gathered from the Feasibility Study Report (FSR) and relevant literatures for the Ninh Thuan 1 NPP site is employed as input parameters. The calculation results indicate that the peak of total exposure dose is estimated to be ca. 0.191 mSv/yr at the time of decommissioning, and then decrease over time. Furthermore, the protected site is assessed to be released at ca. 6.71 years after decommissioning under the regulation on radiation protection in Vietnam. Through this study, a radiation exposure model for residents living near the Ninh Thuan 1 NPP is preliminarily established by using the RESRAD-ONSITE code, which are expected to be useful for future implementation of the Ninh Thuan 1 NPP project in Vietnam.

• Geophysics and Geophysical Exploration
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• v.24 no.2
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• pp.35-44
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• 2021

As the execution speed of Python is slower than those of other programming languages (e.g., C, C++, and FORTRAN), Python is not considered to be efficient for writing numerical geodynamic code that requires numerous iterations. Recently, many computational techniques, such as the Just-In-Time (JIT) compiler, have been developed to enhance the calculation speed of Python. Here, we developed two-dimensional (2D) numerical geodynamic code that was optimized for the JIT compiler, based on Python. Our code simulates mantle convection by combining the Particle-In-Cell (PIC) scheme and the finite element method (FEM), which are both commonly used in geodynamic modeling. We benchmarked well-known mantle convection problems to evaluate the reliability of our code, which confirmed that the root mean square velocity and Nusselt number obtained from our numerical modeling were consistent with those of the mantle convection problems. The matrix assembly and PIC processes in our code, when run with the JIT compiler, successfully achieved a speed-up 30× and 258× faster than without the JIT compiler, respectively. Our Python-based FEM-PIC code shows the high potential of Python for geodynamic modeling cases that require complex computations.

• Journal of Food Hygiene and Safety
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• v.10 no.3
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• pp.175-180
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• 1995

The distribution of bacteria in kimbab and its ingredients have been investigated. The total bacterial counts were over 3$\times$106/g(n=30) when the kimbabs were delivered to restaurant and it exceeded the legal level 1$\times$106/g defined by the Code of Food Standard in 1991. The gram-negative coliforms were also detected 1.9$\times$105. In order to study the cause of bacterial contamination in kimbabs, the ingredients used in kimbabs were examined. The bacterial counts were found 104-108/gfor kim (laver), 104-108/g for sausage, 104-106/g for boiled-spinach, 103-107/g for carrot, and 104-106/g for Danmuji, respectively. From these results it could be concluded that the bacterial contamination in Kimbabs was caused mainly by the ingredients such as kim, boiled-spinach, carrot, and sausage. Therefore, this suggested that the sanitary manufacture of kim, the storage at refrigerator temperature of the ingredients for kimbabs, and the proper treatment of equipments should be maintained in order to reduce the bacterial contamination for kimbabs. Furthermore, it should be required to obtain the basal data for establishment of the sanitary standard of kim and kimbab.

• Journal of Food Hygiene and Safety
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• v.26 no.2
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• pp.182-185
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• 2011

This study was conducted to develop an appropriated management for safety of children snacks sold around school. Total 598 items as targeted food were collected; 66 biscuits, 320 candies, 57 chocolates, 40 ice creams and 115 beverages. Microbiological hazards such as total aerobic bacteria, Coliforms, Escherichia coli, Bacillus ceruse, Yeasts & molds were measured by analytical method in Korean food code. Total aerobic bacteria and Yeasts & molds were detected in cookies at the level of less than 2.69 and 2.65 $log_{10}$ CFU/g and the detection rates were 54.55 and 62.12%, respectively. Bacillus cereus was detected in 1 snack only at the level of 1.39 $log_{10}$ CFU/g but it was less than Korean microbial standards and specifications (3 $log_{10}$ CFU/g). Total aerobic bacteria and Yeasts & molds were detected in candies less than 2.86, 3.36 $log_{10}$ CFU/g and the detection rates were 46,8% respectively. Total aerobic bacteria, Yeast & mold were detected in chocolates at the levels less than 2.52 and 1.87 $log_{10}$ CFU/g and the detection rates were 33 and 22% respectively. Total aerobic bacteria in both ice creams and beverages were detected at the levels less than 3.39 and 1.35 $log_{10}$ CFU/g and the detection rates were 82 and 5% respectively. Coliforms were found in one ice cream (1.39 $log_{10}$ CFU/g) only. The result of this study indicated that all children snacks around school were suitable for microbial standard and specifications in Korean Food Code. However, since most children snacks around school are circulated without proper storage temperature and handing condition, consistent microbial management for children snacks are needed.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2901-2906
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• 2007

A solver for icing and condensation of water has been developed. The phase change process was solved by the enthalpy method. For the code validation, the temperature and the phase change from water to ice of the driven cavity were calculated. Also, the melting process of the frost on the windshield glass of an automobile has been simulated. The calculation showed a good agreement with analytical solution and other numerical results. Using the present validated code, the condensation of water vapor has been first tried. The computed results provided some physical features of condensation phenomena even though experimental data and other numerical data were not available. For future work, it is recommended to throughly investigate the effects of boundary conditions on the solution.

• Wind and Structures
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• v.23 no.5
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• pp.421-447
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• 2016

Wind-induced and earthquake-induced excitations on tall structures can be effectively controlled by Tuned Liquid Damper (TLD). This work presents a numerical simulation procedure to study the performance of tuned liquid tank- structure system through ${\sigma}$-transformation based fluid-structure coupled solver. For this, a 'C' based computational code is developed. Structural equations are coupled with fluid equations in order to achieve the transfer of sloshing forces to structure for damping. Structural equations are solved by fourth order Runge-Kutta method while fluid equations are solved using finite difference based sigma transformed algorithm. Code is validated with previously published results. The minimum displacement of structure is observed when the resonance condition of the coupled system is satisfied through proper tuning of TLD. Since real-time excitations are random in nature, the performance study of TLD under random excitation is also carried out in which the Bretschneider spectrum is used to generate the random input wave.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.89-92
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• 2001

A rigid-viscoplastic finite element code for superplastic forming processes has been developed The material is assumed to be isotropic and a modified Coulomb friction law is adopted to explain contact between tool and sheet. This code uses the triangular element based on the membrane approximation and a hierarchical contact searching method is implemented The optimum pressure-time relationships for target strain rate are calculated by several pressure control algorithms. By the analysis, optimum pressure-time curves and deformation behavior are predicted.