• Title/Summary/Keyword: Critical technology elements

Search Result 222, Processing Time 0.023 seconds

Analysis of Science Social Emotions Learning on Secondary Science Curriculum Achievement Standards and Textbooks (과학과 교육과정 성취기준과 교과서의 사회정서학습 요소 분석)

  • Kim, Seo Young;Park, Hyun Ju
    • Journal of the Korean Chemical Society
    • /
    • v.66 no.2
    • /
    • pp.163-170
    • /
    • 2022
  • This study investigated and analyzed the social and emotional learning components of middle school science, and high school integrated science and science inquiry experiments, which are common subjects that all students must complete. The subjects of analysis were 139 achievement standards of science and curriculum and 496 activities included in textbooks. The research results are as follows. In the case of curriculum achievement standards, 'cultural understanding' was hardly included among the seven science and social-emotional learning elements, 'numeracy' and 'creative thinking' appeared high in middle school, 'critical thinking', 'social technology' and 'ethical understanding' were included with high frequency in high school. And in the case of textbook activity, the tendency of social-emotional learning elements in middle school and high school was similar. 'critical thinking', 'creative thinking', and 'social skills' were mainly provided, while 'ethical understanding' and 'cultural understanding' were reflected in a limited way. In order to cultivate the elements of overall social-emotional learning, it is necessary to specify the achievement standards of the curriculum or to supplement the textbook activities and teaching-learning process.

Performance comparison of shear walls with openings designed using elastic stress and genetic evolutionary structural optimization methods

  • Zhang, Hu Z.;Liu, Xia;Yi, Wei J.;Deng, Yao H.
    • Structural Engineering and Mechanics
    • /
    • v.65 no.3
    • /
    • pp.303-314
    • /
    • 2018
  • Shear walls are a typical member under a complex stress state and have complicated mechanical properties and failure modes. The separated-elements model Genetic Evolutionary Structural Optimization (GESO), which is a combination of an elastic-plastic stress method and an optimization method, has been introduced in the literature for designing such members. Although the separated-elements model GESO method is well recognized due to its stability, feasibility, and economy, its adequacy has not been experimentally verified. This paper seeks to validate the adequacy of the separated-elements model GESO method against experimental data and demonstrate its feasibility and advantages over the traditional elastic stress method. Two types of reinforced concrete shear wall specimens, which had the location of an opening in the middle bottom and the center region, respectively, were utilized for this study. For each type, two specimens were designed using the separated-elements model GESO method and elastic stress method, respectively. All specimens were subjected to a constant vertical load and an incremental lateral load until failure. Test results indicated that the ultimate bearing capacity, failure modes, and main crack types of the shear walls designed using the two methods were similar, but the ductility indexes including the stiffness degradation, deformability, reinforcement yielding, and crack development of the specimens designed using the separated-elements model GESO method were superior to those using the elastic stress method. Additionally, the shear walls designed using the separated-elements model GESO method, had a reinforcement layout which could closely resist the actual critical stress, and thus a reduced amount of steel bars were required for such shear walls.

Stability analysis of pump using finite element method (유한요소법에 의한 펌프축계의 안정성해석)

  • 양보석
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.10 no.4
    • /
    • pp.31-40
    • /
    • 1986
  • With the tendency toward high speed and high pressure in centrifugal pumps, the problem of sub-synchronous vibration has arisen, caused by the hydraulic forces of the working fluid, such as wearring, balance piston, impeller, etc.. These forces can drastically alter the rotor critical speeds and stability characteristics, and can be acted significant destabilizing forces. For preventing such self-excited vibration, the desing of the rotor system needs, which would secure the stability of the machine. In this paper, a procedure is presented for dynamic modeling of rotor-bearing-seal-impeller systems which consist of rigid disks, distributed parameter finite rotor elements and discrete bearings, seals and impellers. A finite element model including the effects of rotatory inertia and gyroscopic moments is developed using the consistent matrix approach. The technique of dynamic matrix reduction is applied to the shaft matrices to reduce them to a set of matrices of dynamic of significantly fewer degrees of freedom. The representation of bearing, seal and impeller elements is in term of linearized stiffness and damping matrices by reasonably small perturbations from equilibrium. The stability behavior of a typical double suction centrifugal pump is presented. Results show the influence of clearance and flow conditions on running speeds and stability characteristics.

  • PDF

Industrial Feature of Rare Metals in Electronic Components (전자부품산업에서의 희소금속의 산업적 특징)

  • Kim, Taek-Soo;Lee, Min-Ha;Kim, Bum-Sung;Choi, Han-Shin;Kim, Yong-Hwan;Lee, Hyo-Soo
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.18 no.2
    • /
    • pp.1-9
    • /
    • 2011
  • Rare metals, called as vitamins of industry, are defined as the elements which are very few in the earth and are difficult to extract from ores. The requirements for total amounts of rare metals have increased as the global economics grows and the function of electronic components varies considerably. The rare metals have been maldistributed to America, CIS(Commonwealth of Independent States), China, Australia, Canada as about 80% of total natural resources, which also lead to unequal materials flow or distribution. Therefore, it was needed to investigate the feature of rare metals in terms of industry as well as technology. We could identify the industrial issues associated with the supply of critical rare elements in electronic components.

Determination of Carbon Equivalent Equation by Using Neural Network for Roll Force Prediction in hot Strip Mill (신경망을 이용한 열간 압연하중 예측용 탄소당량식의 개발)

  • 김필호;문영훈;이준정
    • Transactions of Materials Processing
    • /
    • v.6 no.6
    • /
    • pp.482-488
    • /
    • 1997
  • New carbon equivalent equation for the better prediction for the better prediction of roll force in a continuous hot strip mill has been formulated by applying a neural network method. In predicting roll force of steel strip, carbon equivalent equation which normalize the effects of various alloying elements by a carbon equivalent content is very critical for the accurate prediction of roll force. To overcome the complex relationships between alloying elements and operational variables such as temperature, strain, strain rate and so forth, a neural network method which is effective for multi-variable analysis was adopted in the present work as a tool to determine a proper carbon equivalent equation. The application of newly formulated carbon equivalent equation has increased prediction accuracy of roll force significantly and the effectiveness of neural network method is well confirmed in this study.

  • PDF

DESIGN GUIDELINE FOR BIOSAFETY LABORATORY CONSTRUCTION

  • Tzu-Ping Lo;Sy-Jye Guo
    • International conference on construction engineering and project management
    • /
    • 2005.10a
    • /
    • pp.587-591
    • /
    • 2005
  • The case of laboratory-acquired SARS Corona virus infection in Taiwan has revealed a number of weaknesses in management, construction, and oversight of laboratories. Also, with the increased demands for bio-safety laboratory, there is an urgent need to develop a uniform and comprehensive guidance for architects and construction engineers in the preparation of design and construction. This research investigates the key elements for designers, engineers, and potential owners in biosafety laboratory design and construction. It defines key elements and determines major relationships and standards that should be adhered to when developing site layout. In addition to layout planning and design guidance of biosafety laboratory, this research also interviews the perspective of architects and survey the state-of-the-art technology in Taiwan. It represents the portraits by site investigation. The purpose of the research is to provide guideline of design and avoid potential future conflict to ensure the critical continuity of functions.

  • PDF

Evaluation of Thermal Deformation Model for BGA Packages Using Moire Interferometry

  • Joo, Jinwon;Cho, Seungmin
    • Journal of Mechanical Science and Technology
    • /
    • v.18 no.2
    • /
    • pp.230-239
    • /
    • 2004
  • A compact model approach of a network of spring elements for elastic loading is presented for the thermal deformation analysis of BGA package assembly. High-sensitivity moire interferometry is applied to evaluate and calibrated the model quantitatively. Two ball grid array (BGA) package assemblies are employed for moire experiments. For a package assembly with a small global bending, the spring model can predict the boundary conditions of the critical solder ball excellently well. For a package assembly with a large global bending, however, the relative displacements determined by spring model agree well with that by experiment after accounting for the rigid-body rotation. The shear strain results of the FEM with the input from the calibrated compact spring model agree reasonably well with the experimental data. The results imply that the combined approach of the compact spring model and the local FE analysis is an effective way to predict strains and stresses and to determine solder damage of the critical solder ball.

Study on the Requirement, Consideration, and Critical Baseline in SAR Design Process for the IFSAR Technique (IFSAR 기법 활용을 위해 SAR 설계시 요구조건, 고려사항 및 최대 베이스라인 연구)

  • 홍인표;박한규
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.26 no.11A
    • /
    • pp.1858-1863
    • /
    • 2001
  • SAR data consist of magnitude and phase, and IFSAR technique using phase data is very useful high technology Producing fee height information. To use IFSAR technique effectively in the operation of SAR, this paper suggests the essential requirement and main consideration during SAR design process. Also the critical baseline, one of the principal elements, is derived, and it proposes applicable method through the simulation and discussion to the E-SAR.

  • PDF

Bidirectional Quasi-Cuk DC/DC Converter with Reduced Voltage Stress on Capacitor and Capability of Changing the Output Polarity

  • Asl, Elias Shokati;Sabahi, Mehran
    • Journal of Electrical Engineering and Technology
    • /
    • v.12 no.3
    • /
    • pp.1108-1113
    • /
    • 2017
  • In this paper, a bidirectional topology for quasi-Cuk dc/dc converter with capability of zero-voltage and zero-current-switching (ZVZCS) is proposed. The bidirectional quasi-Cuk (BQ-Cuk) converter has different voltage and current transfer ratio, reduced voltage stress on capacitor and capability of changing the output polarity in comparison with conventional bidirectional Cuk converter. In this paper, steady-state analysis of the quasi-Cuk converter with capability of ZVZCS in turn-on is presented. Then, critical inductances for transient from this operation to two new operations are calculated. Next, besides values designing of used elements, maximum and minimum value of their current and voltage are calculated. Finally, experimental results to verify the accuracy of the proposed converter in different operating modes are presented.

Seismic torsional vibration in elevated tanks

  • Dutta, Sekhar Chandra;Murty, C.V.R.;Jain, Sudhir K.
    • Structural Engineering and Mechanics
    • /
    • v.9 no.6
    • /
    • pp.615-636
    • /
    • 2000
  • Some elevated water tanks have failed due to torsional vibrations in past earthquakes. The overall axisymmetric structural geometry and mass distribution of such structures may leave only a small accidental eccentricity between centre of stiffness and centre of mass. Such a small accidental eccentricity is not expected to cause a torsional failure. This paper studies the possibility of amplified torsional behaviour of elevated water tanks due to such small accidental eccentricity in the elastic as well as inelastic range; using two simple idealized systems with two coupled lateral-torsional degrees of freedom. The systems are capable of retaining the characteristics of two extreme categories of water tanks namely, a) tanks on staging with less number of columns and panels and b) tanks on staging with large number of columns and panels. The study shows that the presence of a small eccentricity may lead to large displacement of the staging edge in the elastic range, if the torsional-to-lateral time period ratio $({\tau})$ of the elevated tanks lies within a critical range of 0.7< ${\tau}$ <1.25. Inelastic behaviour study reveals that such excessive displacement in some of the reinforced concrete staging elements may cause unsymmetric yielding. This may lead to progressive strength deterioration through successive yielding in same elements under cyclic loading during earthquakes. Such localized strength drop progressively develop large strength eccentricity resulting in large localized inelastic displacement and ductility demand, leading to failure. So, elevated water tanks should have ${\tau}$ outside the said critical range to avoid amplified torsional response. The tanks supported on staging with less number of columns and panels are found to have greater torsional vulnerability. Tanks located near faults seem to have torsional vulnerability for large ${\tau}$.