• Particle and aerosol research
• /
• v.8 no.2
• /
• pp.75-81
• /
• 2012

The strength of lumped cokes can be represented by some index numbers. Although some indexes are suggested, these indexes are not enough to enlighten fracture mechanism. To find essential mechanism, a computational way, discrete element method, is applied to the uniaxial compression test for cylindrical specimen. The cylindrical specimen is a kind of lumped particle mass with parallel bonding that will be broken when the normal stress and shear stress is over a critical value. It is revealed that the primary factors for cokes fracture are parallel spring constant, parallel bond strength, bonding radius and packing ratio the parallel bond strength and radius of the parallel combination the packing density. Especially, parallel spring constant is directly related with elastic constant and yield strength.

• Journal of Korean Society of Water and Wastewater
• /
• v.26 no.1
• /
• pp.13-20
• /
• 2012

In this paper, we present the result of an investigation pertaining to the pipe stiffness of buried flexible pipes. Pipe stiffness (PS) formula for the parallel plate loading condition is derived based on the elasticity theory. Vertical and horizontal displacements are also derived. Vertical deflection is always larger than the horizontal deflection because some of energy due to overburden load is stored in the pipe but the difference is negligibly small. In the study, mechanical properties of the flexible pipes produced in the domestic manufacturer are tested and the results are reported in this paper. In addition, pipe stiffness is determined by the parallel plate loading tests and the finite element analysis. The difference between test and analysis is less than 14% although there are significant variations in the mechanical properties of the pipe material. Therefore, it was found that the finite element analysis can be used to predict the pipe stiffness instead of conducting parallel plate loading test.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.53 no.12
• /
• pp.725-731
• /
• 2004

In this study, the three type hybrid interrupters according to the arrangement of the thermal expansion chamber and the puffer cylinder(they are called 'serial type', 'parallel/exchanged type', and 'parallel/separated type' respectively in this work) were designed and manufactured. This paper presents the tested results of the thermal recovery characteristics on the interrupters using a simplified synthetic test facility. The 'serial type' hybrid interrupter which is to obtain more easily the pressure rise for the thermal recovery compared with the others has the best capability in the thermal recovery characteristics. In order to investigate the stress on the operating mechanism, the distortion of the stroke wave in on-load test was examined to the stroke curve in no-load test. The biggest distortion was occurred in the 'parallel/exchanged type' hybrid interrupter. Finally, the small interruption capability on the three type interrupters was estimated by a theoretical form and the 'parallel/separated type' hybrid interrupter has the advantage of the others in the view of structure.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.17 no.7
• /
• pp.666-676
• /
• 1992

In this paper, algorithm and testable circuit to find all PSF(Pattern Sensitive Fault ) occured in RAM were proposed. Conventional test circuit and algorithm took much time in testing because consecutive test for RAM cells or f-dimensional memory struciure was not employed. In this paper, methodology for parallel RAM-testing was proposed by compensating additional circuit for test to conventional RAM circuit. Additional circuits are parallel comparator, error detector, group selector circuit and a modified decoder used for parallel testing. And also, the constructive method of Eulerian path to obtain efficient test pattern was performed. Consequently, If algorithm proposed in this paper Is used, the same operations as 32sxwor4 lines will be needed to test b x w=n matrix RAM. Circuit simulation was performerd, and 10 bits x :If words testable RAM was designed.

• Journal of the Korean Wood Science and Technology
• /
• v.50 no.4
• /
• pp.237-245
• /
• 2022

This study examined the structural performance of experimental parallel strand lumber (PSL) from a Larch veneer strand. The prototype of PSL from a Larch veneer strand was manufactured in the experimental laboratory and tested. The bending and dowel bearing strength were determined from the modulus of elasticity (MOE), modulus of rupture (MOR), and dowel bearing strength based on a 5% offset yield load. The test results indicated that the average MOR of PSL was higher than that of 2 × 4 dimension lumber, and the average MOE of PSL was lower than that of 2 × 4 dimension lumber. A linear relationship was observed between the MOR and MOE. The allowable bending stress of PSL was derived as specified in ASTM D2915 and compared with other research. The dowel bearing strength of PSL in parallel to the grain was approximately double that perpendicular to the grain of PSL. A comparison of several theoretical calculations based on each national code for the dowel bearing strength was conducted, and some theoretical equations produced results closer to the experimental results when it was parallel to the grain, but the difference was higher in the case perpendicular to the grain. The test results showed that PSL made with Japanese larch veneer strands appeared to be suitable for a raw material of structural composite lumber (SCL) appeared to be used as a raw material for SCL.

• Journal of computational fluids engineering
• /
• v.3 no.1
• /
• pp.22-29
• /
• 1998

Parallel implementation is conducted for a SIMPLER finite volume model. The present parallelism is based on domain decomposition and explicit message passing using MPI and SHMEM. Two parallel solvers to tridiagonal matrix equation are employed. The implementation is verified on the Cray T3E system for a benchmark problem of natural convection in a sidewall-heated cavity. The test results illustrate good scalability of the present parallel models. Performance issues are elaborated in view of convergence as well as conventional parallel overheads and single processor performance. The effectiveness of a localized matrix solution algorithm is demonstrated.

• Structural Engineering and Mechanics
• /
• v.14 no.1
• /
• pp.57-70
• /
• 2002

This work presents an iterative mesh partitioning approach to improve the efficiency of parallel substructure finite element computations. The proposed approach employs an iterative strategy with a set of empirical rules derived from the results of numerical experiments on a number of different finite element meshes. The proposed approach also utilizes state-of-the-art partitioning techniques in its iterative partitioning kernel, a cost function to estimate the computational cost of each submesh, and a mechanism that adjusts element weights to redistribute elements among submeshes during iterative partitioning to partition a mesh into submeshes (or substructures) with balanced computational workloads. In addition, actual parallel finite element structural analyses on several test examples are presented to demonstrate the effectiveness of the approach proposed herein. The results show that the proposed approach can effectively improve the efficiency of parallel substructure finite element computations.

• Journal of the Korean Wood Science and Technology
• /
• v.46 no.5
• /
• pp.425-436
• /
• 2018

This study was conducted to evaluate the planar (rolling) shear strength of OSB (oriented strand board) panels and domestic plywood through 5 point bending test method in ASTM D2718 standard. The test specimens were prepared in parallel and perpendicular direction to major axis (along the length of panels) and tested up to failure, and failure modes were also examined. From the test results, rolling shear strength were found to be $1.32{\sim}1.94N/mm^2$ in parallel to major axis, and $1.46{\sim}1.99N/mm^2$ in perpendicular to major axis respectively. Little difference was found between parallel and perpendicular direction of rolling shear strength. There were no statistically significant differences in rolling shear strength between Canadian OSB and domestic plywood in the parallel direction, and between Chilean OSB and domestic plywood in the perpendicular direction. The shear failure was observed in all tested OSB panels, whereas shear failure, glue line delamination, and bending combined with shear failure were observed in the domestic plywood.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.05a
• /
• pp.25-26
• /
• 2012

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1998.04a
• /
• pp.296-301
• /
• 1998

In this experiments of design, vibration evaluation, and test of vehicles, aircraft, and other mechanisms the development of vibration simulator that serves environment similar to real fields takes lots of advantages. Especially, in the real field test of vehicles it possesses the advantages of showing the dynamic characteristics of the vehicle. In this study, to investigate the validity and fitness of proposed 6DOF parallel link mechanism we simulated that mechanism.