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[en] In solving partial differential equations using finite element method, the great parts of the computing time is taken to calculate the local element matrices. Also the much programming efforts are taken for the local element matrices calculations. To reduce the computing time and the efforts of programming, local elements matrices are calculated by symbolic manipulation method. In this study, symbolic manipulation code REDUCE 3.2 is used. As a results, Fortran subroutine form of local element matrices package is obtained. Using this package, programming efforts would be much reduced. Also the computing time is greatly reduced using the developed package. As a conclusion, it can be said that the developed method can be used to solve the partial differential equation with the less computing times and the less programming efforts than the conventional method
[en] An analytical model is developed to predict the heat transfer coefficient and the friction factor in the inverted annular film boiling. The developed model is based on two-fluid mass, momentum and energy balance equations and a theoretical velocity profile. The predictions of the proposed model are compared with the experimental data and the well-established correlations. For the heat transfer coefficient, they agree with the experimental data and are more promising than those of Bromely and Berenson correlations. The present model also accounts the effects of the mass flux and subcooling on the heat transfer. The friction factor predictions agree qualitatively with the experimental measurements, while some cases show a similar behavior with those of the post-CHF dispersed flow obtained from Beattie's correlation
[en] A new simple correlation for subcooled and two-phase critical flow discharge coefficient has been developed by stepwise regression technique. The new discharge coefficient has three independent variables and they are length to hydraulic diameter ratio, degree of subcooling, and stagnation temperature. The new discharge coefficient is applied as a multiplier to homogeneous equilibrium model and Abauf's single phase critical mass flux calculation equation. This method has been tested for its accuracy by comparing with experimental data. Results of the comparison show that the agreement between the predictions with new correlation and the experimental data is good for pipes and nozzles with vertical upward flow for subcooled upstream condition and nozzles with horizontal configuration for two-phase upstream condition
[en] The contents of this book are birth of VE, development of VE in Korea, management of VE and other thing, applied field of VE, basic thinking method of VE, value, definition of VE, practice of VE activity, steps of VE, collection of data, selection of theme of target follow-up after VE proposal, preparation of meeting and progression method, and propel method of VE like data collection, definition, arrangement, assessment of function, making and proposal.
[en] This book introduces WAVE method with finding theme, finding role, finding idea and finishing. It tells of the methods of finding introducing arranging the phenomenon on checklist, checking the place problems are selecting the theme, setting goal to improve and deciding the theme, confirming the target of theme which was decided, asking question on what for, finding the answer for the question, choosing a good idea and thinking back the activity.
[en] This book first gives descriptions of using of this hand book and contents. It tells of steel such as bar steel, section steel, and steel sheet which are steel for general structure and steel for pressure vessel, a steel pipe, carbon steel for machine structure and alloy steel, steel for special things, stainless steel, heat resisting steel, tool steel, spring steel, forging, steel casting, nonferrous metal such as aluminium and aluminium alloy, casting, list of similar steel per metal, list of steel like ASTM, AISI per number, and list of collecting standard per metal material.
[en] This book introduces spur gear including helical gear, bevel gear like straight bevel gear and spiral bevel gear, warm gear, hypoid gear, precautions of design of toothed gear, belt, rope and chain, cam and urgent screw, uniform rotary machine, speed change machine, machine for back and forth motion like machine by screw, belt, mangle gear, and chain, brake machine, such as clutch, and escape of spring, feed machine, curvilinear motion machine and measuring machine.
[en] This book introduces scientific technique and national development such as opportunity of jump, the future of Korean science, a balanced development of scientific technique system, and the role of scientific technique advisory conference, train of brain resource for advancement like preparation for lead generation in the 2000s and advancement and brain resource, the role of university and promotion of basic studying such as characteristic of basic research and the role of Korea Science and Engineering Foundation and establishment of group research system, consolidation of interface function for technical innovation and dream of scientist for the 21 century.
[en] Ultrasonic testing is one of the most useful NDT method for detection of microdefect in the opaque materials. Recently, many applications of the ultrasonic techniques have been extended widely in the new field like electron is and advanced materials. From the result of the experiment, we have hardly found out a crack in the internal parts of the resin and a delamination between chip and resin because of poor performance of the system
[en] This paper presents the ultrasonic characteristics of weldment and detectability of defects of weldment in Austenitic Stainless Steel Type 304 that is composed of mostly coolant piping system in nuclear power plants. The results of this experiment show as follows: 1. When the ultrasonic beam detects the defects on the side of base metal and on the opposite side of weldment, the indications which was detected on the screen show different amplitude and different metal path each. 2. The ultrasonically estimated notch depth is generally oversized than actual notch depth. 3. It is easy for the false indication to show up on the screen because of columnar structure of weldment in austenitic stainless steel. 4. The higher frequencies of transducer have more difficulties to detect the defects of the opposite side of weldment because of ultrasonic attenuation in weldment and the longitudinal transmitter-receiver transducer is the most effective in detecting the opposite side defects of weldment