Passive damping

Selection from existing or innovative Construction Methods, Schedules and Designs to Adapt projects to the Latest Understanding of the Changing Risks due to Climate at each individual site (e.g., the passive damping system at the Taipei Financial Center). 

Chan KW, Liao WH, Shen lY (2008) Precision positirai-ing of hard disk drives using piezoelectric actuators with passive damping. IEEE Trans Mechatron 13(1) 147-151... 

Gas Spring Invention to increase the restoring forces ofTLCGD by the compressibiUty ofthe gas. Passive Damping with Dynamic Absorber ... 

Alhan, C., Gavin, H. (2004). A parametric study of linear and nonlinear passively damped seismic isolation system for buildings. Engineering Structures, 24, 485-497. doi 10.1016/j. engstmct.2003.11.004... 

In Fig. 2, a schematic view of the well-known passive damped oscillator is drawn. A mass m is fixed to one end of a spring of elastic constant L The other end of the spring is fixed to a frame anchored to the ground. The motion is mechanically limited to the horizontal axis shown. When the ground moves a displacement... 

The wash primer is a special type of vinyl coating. This material contains a poly(vinyl butyral) resin, zinc chromate, and phosphoric acid in an alcohol-water solvent. The coating is so thin it is HteraUy washed onto a freshly blasted steel surface, where it passivates the metal surface by converting it to a thin iron phosphate-chromate coating. The alcohol solvent makes it possible to apply the coating over damp surfaces. The coating forms the first coat of... 

The passivating action of an aqueous solution within porous concrete can be changed by various factors (see Section 5.3.2). The passive film can be destroyed by penetration of chloride ions to the reinforcing steel if a critical concentration of ions is reached. In damp concrete, local corrosion can occur even in the presence of the alkaline water absorbed in the porous concrete (see Section 2.3.2). The Cl content is limited to 0.4% of the cement mass in steel-concrete structures [6] and to 0.2% in prestressed concrete structures [7]. 

Little information is available about the corrosion of metals in concrete, although it seems likely that all Portland cements, slag cement and high-alumina cement behave similarly Concrete provides an alkaline environment and, under damp conditions, the metals behave generally as would be expected e.g. zinc, aluminium and lead will react, copper is unaffected, while iron is passivated by concrete. 

Careful sealing of the floor-to-wall joints and of the ground floor walls was unsuccessful in reducing pressure-driven flow of radon from the subsoil. This merely diverted the flow of radon up through the internal walls of the dwelling and into upstairs rooms. The problem arose in this old dwelling because it has very porous walls and no damp proof course, thus allowing radon to by-pass the sealed floor. Incorporation of a passive radon barrier into the floor of a modern house with less porous walls is likely to be effective. 

V0/V/ (fti), to the analytical expression with recovery of the complete quartz impedance near resonance (admittance, conductance and impedance). Although the voltage divider method does not measure the transfer function phase and hence it is not possible to demonstrate the validity of BVD circuit, it has the advantage of speed. Also passive methods like TFM can be applied under high viscous damping so that the shear wave phase never crosses zero and the EQCM no longer resonates. 

Some of what we see as the principal properties and characteristics of import in the development and selection of viscoelastic materials for structural damping are listed below. Table IV notes "passive" properties and characteristics, that is, those that pertain to the material itself and to its performance in the specified operating conditions. Somewhat in contrast. Table V lists "Active or Interactive" properties and characteristics that concern the interaction of the viscoelastic material with other materials and with the environment of the treatment. These tabulations are surely incomplete, but are intended to suggest the breadth of considerations that may be involved in material selection. 

Table IV. Viscoelastic Materials for Damping. Passive Properties and Characteristics...

AFM operation requires a minimum of vibrations. These vibrations refer to not only building vibrations, but also vibrations caused by airflow, persons walking in the lab, and equipment, such as personal computers, the AFM controller, etc. To damp out vibrations, AFM scan units are typically placed on passive and/or active vibration damping systems, such as ... 

Eckhardt B, Schumacher J (2004) Turbulence and passive scalar transport in a free slip surface. Physical Review E, 64 016314 Foss M (2001) Wave damping and momentum transfer. Doctoral thesis, University of Tromso, Norway... 

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