• Title/Summary/Keyword: Critical Section

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The Dutch RE;MIND Design's Conceptual and Critical Aesthetics of Use (네덜란드 RE;MIND 디자인의 개념적·비평적 사용미학)

  • Park, Young-Tae
    • Korean Institute of Interior Design Journal
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    • v.23 no.2
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    • pp.51-61
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    • 2014
  • Aesthetics of use for modern people can be regarded as being weighted toward universal and rational function since it has focused on an 'automation and efficiency' and 'smartness' in terms of technological and human engineering position. Thus, aesthetics of use as an individual agent has remained in minimal level. This study attempts to seek conceptual model of design regarding the behavior of users from the systematization of critical theories about the usability. To do that, 'HERTZAIN TALES' written by Anthony Dune and the concept and system of Droog Design have been used as a core standard. In line with the various experiments by artist groups such as Fluxus, Memphis group and the work of product semantics, and inherent characteristics of Droog design, which has surfaced from the 1990s, concepts that has mentioned in the Hertzain tales have been organized into main texts. By overcoming cognitive bias inherent in the material culture and by overcoming an existing usability based on immateriality and dialectic solution, the autonomy of critical design and instrumentality of Droog design have been systemized. By interpreting the design aspect of 12 pieces that have been submitted to the RE;MIND section, the core of this study, it has been confirmed that conceptual and critical design's aesthetics of use From the interpretation of the design aspect of 12 pieces that have been submitted to the RE;MIND section, the core of this study, it has been confirmed that conceptual and critical design's aesthetics of use has established the autonomy and independence of the behavior of users, created functional articulation of materials and secured new conceptual model and thus, could be an effective methodical clue for creating an emergent design.

Improvement and application of DeCART/MUSAD for uncertainty analysis of HTGR neutronic parameters

  • Han, Tae Young;Lee, Hyun Chul;Cho, Jin Young;Jo, Chang Keun
    • Nuclear Engineering and Technology
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    • v.52 no.3
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    • pp.461-468
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    • 2020
  • The improvements of the DeCART/MUSAD code system for uncertainty analysis of HTGR neutronic parameters are presented in this paper. The function for quantifying an uncertainty of critical-spectrumweighted few group cross section was implemented using the generalized adjoint B1 equation solver. Though the changes between the infinite and critical spectra cause a considerable difference in the contribution by the graphite scattering cross section, it does not significantly affect the total uncertainty. To reduce the number of iterations of the generalized adjoint transport equation solver, the generalized adjoint B1 solution was used as the initial value for it and the number of iterations decreased to 50%. To reflect the implicit uncertainty, the correction factor was derived with the resonance integral. Moreover, an additional correction factor for the double heterogeneity was derived with the effective cross section of the DH region and it reduces the difference from the complete uncertainty. The code system was examined with the MHTGR-350 Ex.II-2 3D core benchmark. The keff uncertainty for Ex.II-2a with only the fresh fuel block was similar to that of the block and the uncertainty for Ex.II-2b with the fresh fuel and the burnt fuel blocks was smaller than that of the fresh fuel block.

Modeling of self-excited forces during multimode flutter: an experimental study

  • Siedziako, Bartosz;iseth, Ole O
    • Wind and Structures
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    • v.27 no.5
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    • pp.293-309
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    • 2018
  • The prediction of multimode flutter relies, to a larger extent than bimodal flutter, on accurate modeling of the self-excited forces since it is challenging to perform experimental validation by using aeroelastic tests for a multimode case. This paper sheds some light on the accuracy of predicted self-excited forces by comparing numerical predictions of self-excited forces with measured forces from wind tunnel tests considering the flutter vibration mode. The critical velocity and the corresponding flutter vibration mode of the Hardanger Bridge are first determined using the classical multimode approach. Then, a section model of the bridge is forced to undergo a motion corresponding to the flutter vibration mode at selected points along the bridge, during which the forces that act upon it are measured. The measured self-excited forces are compared with numerical predictions to assess the uncertainty involved in the modeling. The self-excited lift and pitching moment are captured in an excellent manner by the aerodynamic derivatives. The self-excited drag force is, on the other hand, not well represented since second-order effects dominate. However, the self-excited drag force is very small for the cross-section considered, making its influence on the critical velocity marginal. The self-excited drag force can, however, be of higher importance for other cross-sections.

Reynolds number and scale effects on aerodynamic properties of streamlined bridge decks

  • Ma, Tingting;Feng, Chaotian
    • Wind and Structures
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    • v.34 no.4
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    • pp.355-369
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    • 2022
  • Section model test, as the most commonly used method to evaluate the aerostatic and aeroelastic performances of long-span bridges, may be carried out under different conditions of incoming wind speed, geometric scale and wind tunnel facilities, which may lead to potential Reynolds number (Re) effect, model scaling effect and wind tunnel scale effect, respectively. The Re effect and scale effect on aerostatic force coefficients and aeroelastic characteristics of streamlined bridge decks were investigated via 1:100 and 1:60 scale section model tests. The influence of auxiliary facilities was further investigated by comparative tests between a bare deck section and the deck section with auxiliary facilities. The force measurement results over a Re region from about 1×105 to 4×105 indicate that the drag coefficients of both deck sections show obvious Re effect, while the pitching moment coefficients have weak Re dependence. The lift coefficients of the smaller scale models have more significant Re effect. Comparative tests of different scale models under the same Re number indicate that the static force coefficients have obvious scale effect, which is even more prominent than the Re effect. Additionally, the scale effect induced by lower model length to wind tunnel height ratio may produce static force coefficients with smaller absolute values, which may be less conservative for structural design. The results with respect to flutter stability indicate that the aerodynamic-damping-related flutter derivatives 𝘈*2 and 𝐴*1𝐻*3 have opposite scale effect, which makes the overall scale effect on critical flutter wind speed greatly weakened. The most significant scale effect on critical flutter wind speed occurs at +3° wind angle of attack, which makes the small-scale section models give conservative predictions.

Buckling analysis of semi-rigid gabled frames

  • Rezaiee-Pajand, Mohammad;Shahabian, Farzad;Bambaeechee, Mohsen
    • Structural Engineering and Mechanics
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    • v.55 no.3
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    • pp.605-638
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    • 2015
  • It is intended to perform buckling analysis of steel gabled frames with tapered members and flexible connections. The method is based on the exact solutions of the governing differential equations for stability of a gabled frame with I-section elements. Corresponding buckling load and subsequently effective length factor are obtained for practical use. For several popular frames, the influences of the shape factor, taper ratio, span ratio, flexibility of connections and elastic rotational and translational restraints on the critical load, and corresponding equivalent effective length coefficient are studied. Some of the outcomes are compared against available solutions, demonstrating the accuracy, efficiency and capabilities of the presented approach.

Flexural Adhesive Behavior of Full-scale RC Beams Strengthened by Carbon Fiber Sheets (실물모형 실험에 의한 탄소섬유쉬트 보강 RC 보의 휨 부착거동)

  • 최기선;류화성;최근도;이한승;유영찬;김긍환
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.1003-1008
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    • 2001
  • It is recently reported that bond failure can be initiated in the region where maximum bending moment and shear force is acted by accompanying shear deformation after flexural crack in full-scale RC beams strengthened by CFRP. Such a shear deformation effect causing bond failure is relatively little in the case of small-scale specimens. So, additional reinforcing details to the critical beam section where maximum moment and shear were acted is required to prevent the bond failure caused by the shear deformations. The U-type wrapping methods by CFRP to the critical beam section is proposed and tested in this paper. Also, the applicability of design bond strength derived from the tests of small-scale beam was investigated by the full-scale RC beam strengthened by CFRP.

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Experimental Study about Punching Shear Strength of Biaxial Hollow slab with Donut type Hollow Sphere (도넛형 중공형성체를 사용한 중공슬래브의 뚫림 전단 성능에 관한 실험적 연구)

  • Chung, Joo-Hong;Choi, Hyun-Ki;Lee, Seung-Chang;Choi, Chang-Sik
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.59-60
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    • 2010
  • This paper presents the flexural capacities of biaxial hollow slab with donut type hollow sphere. To verify the punching shear capacities of this biaxial hollow slab, punching shear tests were performed. The test parameter was the areas of critical section which were determined by the number of hollow spheres in critical section.

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A Fault-tolerant Mutual Exclusion Algorithm in Asynchronous Distributed Systems

  • Kim, Yoon
    • International Journal of Contents
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    • v.8 no.4
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    • pp.1-6
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    • 2012
  • Mutual Exclusion is one of the most studied topics in distributed systems where processes communicate by asynchronous message passing. It is often necessary for multiple processes at different sites to access a shared resource or data called a critical section (CS) in distributed systems. A number of algorithms have been proposed to solve the mutual exclusion problem in distributed systems. In this paper, we propose the new algorithm which is modified from Garg's algorithm[1] thus works properly in a fault-tolerant system. In our algorithm, after electing the token generator, the elected process generates a new token based on the information of the myreqlist which is kept by every process and the reqdone which is received during election. Consequently, proposed algorithm tolerates any number of process failures and also does even when only one process is alive.

NEUTRONICS MODELING AND SIMULATION OF SHARP FOR FAST REACTOR ANALYSIS

  • Yang, W.S.;Smith, M.A.;Lee, C.H.;Wollaber, A.;Kaushik, D.;Mohamed, A.S.
    • Nuclear Engineering and Technology
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    • v.42 no.5
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    • pp.520-545
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    • 2010
  • This paper presents the neutronics modeling capabilities of the fast reactor simulation system SHARP, which ANL is developing as part of the U.S. DOE's NEAMS program. We discuss the three transport solvers (PN2ND, SN2ND, and MOCFE) implemented in the UNIC code along with the multigroup cross section generation code $MC^2$-3. We describe the solution methods and modeling capabilities, and discuss the improvement needs for each solver, focusing on massively parallel computation. We present the performance test results against various benchmark problems and ZPR-6 and ZPPR critical experiments. We also discuss weak and strong scalability results for the SN2ND solver on the ZPR-6 critical assembly benchmarks.

Post-buckling behaviours of axially restrained steel columns in fire

  • Li, Guo-Qiang;Wang, Peijun;Hou, Hetao
    • Steel and Composite Structures
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    • v.9 no.2
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    • pp.89-101
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    • 2009
  • This paper presents a simplified model to study post-buckling behaviours of the axially restrained steel column at elevated temperatures in fire. The contribution of axial deformation to the curvature of column section is included in theoretical equations. The possible unloading at the convex side of the column when buckling occurs is considered in the stress-strain relationship of steel at elevated temperatures. Parameters that affect structural behaviours of the axial restrained column in fire are studied. The axial restraint cause an increase in the axial force before the column buckles; the buckling temperature of restrained columns will be lower than non-restrained steel columns. However, the axial force of a restrained column decreases after the column buckles with the elevation of temperatures, so make use of the post-buckling behaviour can increase the critical temperature of restrained columns. Columns with temperature gradient across the section will produce lower axial force at elevated temperatures.