BACKGROUND This study was designed to investigate the effects of the vitamins C and B12 on the regulation of human nasal ciliary beat frequency (CBF). METHODS Human nasal mucosa was removed endoscopically and nasal ciliated cell culture was established. Changes of CBF in response to different concentrations of vitamin C or vitamin B12 were quantified by using high-speed (240 frames per second...

Abstract A computational study was conducted to examine the seismic performance of steel moment‐resisting frames (MRFs) provided with chevron concentric braces. Such systems are widely used for buildings in Japan. Nonlinear finite‐element‐method models were validated against data and observations from previously tested chevron‐braced MRF specimens. The conduct a parametric understand how cyclic...

Abstract Shear dampers are known as famous seismic passive energy devices due to their suitable performance against loading improve the behavior of Concentrically Braced Frames (CBFs). The CBF system suffers from low ductility its compression member's susceptibility buckling. By adding shear directly diagonal element members CBF, prevent bucking and system. Although pertain high dissipation cap...

plate heat exchangers are widely used in industries due to their special characteristics, such as high thermal efficiency, small size, light weight, easy installation, maintenance, and cleaning. the purpose of this study is to consider the effect of depth, angle, and pitch of hemispheric chevrons on the convective heat transfer coefficient and pressure drop. in the simulation of the heat exchan...

Shaoyi Jiang,† Rawls Frazier,‡ Elaine S. Yamaguchi,§ Mario Blanco,† Siddharth Dasgupta,† Yanhua Zhou,† Tahir Cagin,† Yongchun Tang,| and William A. Goddard, III*,† Materials and Process Simulation Center, Beckman Institute (139-74), DiVision of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, CheVron Research and Technology Company, 100 CheVron...

the knee bracing steel frame (kbf) is a new type of energy dissipating frame which enjoys exceptional ductility and lateral stiffness. rather than the beam-column joint, one end of the diagonal brace in kbf is attached to the knee element. indeed, the knee element as a hysteretic damper is designed and detailed to behave like a structural fuse by sustaining controlled inelastic deformations as ...

cast connections. ABSTRACT: Diagonal bracings are extremely popular elements for lateral load resistance in steel-framed buildings. In turn, the most common shape used for bracing members is the hollow structural section. While the design of such members is straight-forward, the design of gusset-plate connections at the member ends is controversial. This paper reviews the current ‘state-of-the-...

Due to low stiffness of braces after yielding, the structures with buckling-restrained braces (BRBs) experience high residual drifts during an earthquake, which can be intensified by aftershocks and causes considerable damages to structures. Also, due to poor distribution of stiffness, this problem is exacerbated for irregular structures. Recently, the yielding brace system (YBS) has been intro...

In this work, a general method for the design of concentric braced steel frames (CBF) with active tension diagonal bracings, applicable to single- and multi-storey structures, is presented. The based on use an elastic modal analysis response spectrum, which carried out using appropriate modified stiffness bracings. reliability proposed validated through significant case studies, making series n...

hysteretic dampers as the most practical passive control methods have improved the seismic performance of steel structures through energy dissipation induced by large inelastic deformations. among them in this paper, kbf (knee braced frames), a special form of braced frames having a diagonal brace connected to a knee element instead of beam-column joint, is investigated. in such systems, the kn...