• Title/Summary/Keyword: P-delta effects

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The Impact of Singing Bowl Healing on the Autonomic Nervous System and Brainwaves (싱잉볼 힐링이 자율신경계 반응과 뇌파에 미치는 영향)

  • Youn-Kyung Jun;Geo-Lyong Lee
    • Science of Emotion and Sensibility
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    • v.26 no.4
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    • pp.125-132
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    • 2023
  • This study investigated the effects of continuous Singing Bowl healing on brainwaves and autonomic nervous system responses. The variations in brainwaves were measured during 45-minute sessions in eight participants, before and after Singing Bowl healing sessions to assess the changes in brainwaves before and after five weeks of Singing Bowl healing treatment. BioBrain BIOS-S8 was used to obtain brainwave measurements. Electrodes were placed on six channels: F3, F4, T3, T4, P3, and P4. A standard limb lead I with electrodes was used for electrocardiogram (ECG) measurements. Using the collected brainwave data, changes in brain waves were observed before and after five weeks of Singing Bowl healing. Beta waves, alpha waves, and sensorimotor rhythm were found to have reduced, while theta waves, delta waves, and the standard deviation of normal-to-normal intervals in heart rate variability had increased. These results indicate that continuous Singing Bowl healing over five weeks can stabilize brainwaves, activate the autonomic nervous system, and increase the relaxation-inducing effects of the parasympathetic nervous system.

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SERS of Dithiocarbamate Pesticides Adsorbed on Silver Surface; Thiram

  • Kang, Jae-Soo;Hwang, Seon-Yeong;Lee, Chul-Jae;Lee, Mu-Sang
    • Bulletin of the Korean Chemical Society
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    • v.23 no.11
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    • pp.1604-1610
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    • 2002
  • In the present work, we studied thiram on silver surface by SERS. Investigations of disulfides with SERS revealed that the molecules undergo a surface reaction on silver, namely easy cleavage of the S-S bond. We believe that the two S atoms of resonance formed from the thiram may be chemisorbed strongly on Ag sol. This resonance form adheres perpendicularly to the Ag surface via the two S atoms, since the ${\delta}(CH3)$ and n (CN) mode perpendicular to the surface showed strong enhancement. The important roles of halide anion adsorption have been discussed and the pH effects of thiram on Ag sol in acidic, neutral, and alkaline conditions were examined.

Experimental Study of High Strength Concrete Beam-Column-Slab Connections subjected to cyclic loading (고강도 콘크리트 보-기둥-슬래브 접합부의 반복하중 실험)

  • 오영훈;오정근;장극관;김윤일
    • Proceedings of the Korea Concrete Institute Conference
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    • 1995.04a
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    • pp.339-344
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    • 1995
  • In the design of ductile moment-resisting frames (DMRFs) following the strong column-weak beam dsign philosophy, it is desirable that the joint and column remain essentially elastic in order to insure proper energy dissipation and lateral stability of the structure. The joint has been identified as the "weak link" in DMRFs because any stiffness or strength deterioration in this region can lead to substantial drifts and the possibility of collapse due to P-delta effects. Moreover, the engineer is faced with the difficult task of detailing an element whose size is determined by the framing members, but which must resist a set of loads very different from those used in the design of the beams and columns. Four 2/3-scale beam-column-slab joint assemblies were designed according to existing code requirements of ACI 318-89, representing interior joints of DMRFs with reinforced high strength concrete. The influence on aseismic behavior of beam-column joints due to monolithic slab, has been investigated.estigated.

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Dynamic Instability of Diagonally Braced Steel Frames under Seismic Excitation (대각선 철골 중심가새골조의 지질동하에서의 동적불안정 거동)

  • 김정재;이철호
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2004.10a
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    • pp.288-295
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    • 2004
  • Concentrically braced steel frames are considered as being quite pone to soft-story response due to the degradation in brace compressive resistance after buckling under severe ground motions. When combined with the system P-Delta effects, collapse of the concentrically brsced frames by dynamic instability becomes highly probable. In this stidy, a new, relatively simple dynamic instability coefficient was proposed for diagonally braced steel flames by explicitly considering the strength degradation of the brace after buckling. Nonlinear dynamic analysis results showed that the dynamic instability coefficient proposed in this study predicted collapse limit state more consistently than the conventional one which ignores the strength degradation of the brace.

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Dynamic Instability Behavior of Diagonally Braced Steel Frames under Seismic Excitation (지진하중을 받는 대각선 철골 중심가새골조의 동적 불안정 거동)

  • Lee, Cheol-Ho;Kim, Jung-Jae
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2005.03a
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    • pp.129-136
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    • 2005
  • Concentrically braced steel frames are considered as being quite prone to soft-story response due to the degradation in brace compressive resistance after buckling under severe ground motions. When combined with the system P-Delta effects, collapse of the concentrically braced frames by dynamic instability becomes a highly probable. In this study, a new, relatively simple dynamic instability coefficient was proposed for diagonally braced steel frames by considering the strength degradation of the brace after buckling. Nonlinear dynamic analysis was conducted to check the robustness of the proposed index based on simulated ground motions. The analysis results showed that the dynamic instability index proposed predicts the collapse potential more consistently than the conventional one. Dynamic instability was triggered when the index value was close to 0.7.

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Seismic performance of low and medium-rise RC buildings with wide-beam and ribbed-slab

  • Turker, Kaan;Gungor, Ilhan
    • Earthquakes and Structures
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    • v.15 no.4
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    • pp.383-393
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    • 2018
  • In this study, seismic performance of low and medium-rise RC buildings with wide-beam and ribbed-slab were evaluated numerically. Moment resisting systems consisting of moment and dual frame were selected as structural system of the buildings. Sufficiency of moment resisting wide-beam frames designed with high ductility requirements were evaluated. Upon necessity frames were stiffen with shear-walls. The buildings were designed in accordance with the Turkish Earthquake Code (TEC 2007) and were evaluated by using the strain-based nonlinear static method specified in TEC. Second order (P-delta) effects on the lateral load capacity of the buildings were also assessed in the study. The results indicated that the predicted seismic performances were achieved for the low-rise (4-story) building with the high ductility requirements. However, the moment resisting frame with high ductility was not adequate for the medium-rise building. Addition of sufficient amount of shear-walls to the system proved to be efficient way of providing the target performance of structure.

A Study on the Flexibility of Semi-Rigid Steel Frames under Lateral Loadings( II ) (횡하중을 받는 반강접 철골 골조의 유연도에 관한 연구( II ) -골조 해석모형을 중심으로-)

  • Kang, Cheol Kyu;Han, Young Cheol;Lee, Gab Jo
    • Journal of Korean Society of Steel Construction
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    • v.8 no.4 s.29
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    • pp.121-131
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    • 1996
  • Semi-rigid frames are frames for whcih the connections joining the beam and column are neither fully rigid nor perfectly pinned. In reality, all steel frames are semi-rigid in nature as all connections exhibit a certain degree of flexibility under loads. For semi-rigid frmaed structures, it is tended to reduce more rigidity of the member for the nonlinear behavior of connections and the P-delta effects of framed structure. To predict the actual behavior of semi-rigid steel frames, a more realistic analysis methods which explicitly takes into account the effect of connection flexibility should be used. In this research, the effect of connection flexibility in the semi-rigid structure has been investigated. To predict the response of flexibility connected frames, the algorithm of semi-rigid steel frame is developed using connection model having nonlinear spring on end of beam.

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Genetic algorithm based optimum design of non-linear steel frames with semi-rigid connections

  • Hayalioglu, M.S.;Degertekin, S.O.
    • Steel and Composite Structures
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    • v.4 no.6
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    • pp.453-469
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    • 2004
  • In this article, a genetic algorithm based optimum design method is presented for non-linear steel frames with semi-rigid connections. The design algorithm obtains the minimum weight frame by selecting suitable sections from a standard set of steel sections such as European wide flange beams (i.e., HE sections). A genetic algorithm is employed as optimization method which utilizes reproduction, crossover and mutation operators. Displacement and stress constraints of Turkish Building Code for Steel Structures (TS 648, 1980) are imposed on the frame. The algorithm requires a large number of non-linear analyses of frames. The analyses cover both the non-linear behaviour of beam-to-column connection and $P-{\Delta}$ effects of beam-column members. The Frye and Morris polynomial model is used for modelling of semi-rigid connections. Two design examples with various type of connections are presented to demonstrate the application of the algorithm. The semi-rigid connection modelling results in more economical solutions than rigid connection modelling, but it increases frame drift.

Optimum design of steel frames with semi-rigid connections using Big Bang-Big Crunch method

  • Rafiee, A.;Talatahari, S.;Hadidi, A.
    • Steel and Composite Structures
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    • v.14 no.5
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    • pp.431-451
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    • 2013
  • The Big Bang-Big Crunch (BB-BC) optimization algorithm is developed for optimal design of non-linear steel frames with semi-rigid beam-to-column connections. The design algorithm obtains the minimum total cost which comprises total member plus connection costs by selecting suitable sections. Displacement and stress constraints together with the geometry constraints are imposed on the frame in the optimum design procedure. In addition, non-linear analyses considering the P-${\Delta}$ effects of beam-column members are performed during the optimization process. Three design examples with various types of connections are presented and the results show the efficiency of using semi-rigid connection models in comparing to rigid connections. The obtained optimum semi-rigid frames are more economical solutions and lead to more realistic predictions of response and strength of the structure.

Characterization of Cinnamaldehyde-Supplemented Soy Protein Isolate Films

  • Kim, Ki-Myong;Hanna, Milford A.;Weller, Curtis L.;Cho, Sung-Hwan;Choi, Sung-Gil
    • Food Science and Biotechnology
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    • v.15 no.4
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    • pp.631-634
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    • 2006
  • Soy protein isolate (SPI) films were supplemented with cinnamaldehyde (CA) at concentrations of 0.1-0.5 mL/5 g SPI. The effects of CA on film color, tensile strength (TS), percent elongation at break (E, %) and water vapor permeability (WVP) of SPI films were investigated. Generally, total color difference (${\Delta}E$), WVP, and TS of SPI films increased gradually, while E and TSM decreased significantly (p<0.05) as the amount of cinnamaldehyde in the SPI films increased. Cinnamaldehyde can be used as a potential cross-linking agent for preparing SPI films by improving mechanical strength and water resistant properties.