Vibrating reed technique

In the vibrating reed technique one end of a small sample is clamped in a gramophone record cutter head driven by a variable frequency oscillator. The amplitude of vibration is measured opto-electrically. enabling tan <5 to be calculated from the width of the resonance, sihce tan = Af. fr where f is the resonant frequency and A/ the bandwidth. 

B. S. Berry and W. C. Pritchet, Defect Studies of Thin Layers by the Vibrating-Reed Technique, J. de Physique 42 C5-1111 (1981). 

The specific heat of both polymers was measured with the heat pulse technique in semiadiabatic fashion. The thermal conductivity was measured with a top loading He refngerator using the standard procedure. The acoustic properties, sound velocity and attenuation, were measured with the vibrating reed technique [16] in the frequency range (0.2 3) kHz. 

Hz, and the S44 measurements at 1 Hz. Robertson and Buenker used the vibrating reed technique to obtain values in the range 100 00 Hz. 

The design and development of a novel vibrating reed technique for on-line measurement of the sedimentation kinetics of two-phase dispersions is described. The technique has been tested in conjunction with a variety of solid/liquid and liquid/liquid dispersions with dense phase concentrations in the range 0-50 % v/v. Typical output include settling velocities, solids flux profiles as well as solids throughputs. Additionally, the performance of a number of sedimentation kinetics models proposed for dilute systems (0 - 2.81 % v/v) are evaluated by comparison with data obtained using the device. 

In this study we report the design and development of a novel remote drive vibrating reed technique for the on-line monitoring of sedimentation kinetics that overcomes most of the above problems. The principle of operation of the device is simple and relies on the fact that the resonant fi-equency of a stiff reed performing simple harmonic motion in a fluid medium is directly related to the fluid hydrodynamic head. 

Resonance-Forced Vibration. Resonance-forced vibration devices drive the vibration of the specimen. This can be over a range of frequencies that includes the resonant frequency, which is detected as a maximum in the ampHtude, or the instmment can be designed to detect the resonant frequency and drive the specimen at that frequency. An example of the resonance-forced vibration technique is the vibrating reed. A specimen in... 

For measurements of ultraviolet light from a quartz mercury arc passes through a quartz monochromator, silica lens, and window, and is focused onto the crystal at an angle of incidence of about 45°. The saturated photocurrent is collected by the surrounding metal drum to determine ip by the Fowler method (4). A vacuum thermopile measures the light intensity. Photoelectric and diffraction currents are measured by a vibrating reed electrometer. Ultra-high-vacuum techniques are employed, which result in residual pressures of less than 10-9 mm. of Hg. 

Samples of poly(4-methyl-l-pentene) (P4MP1) prepared from mats of dilute solution-crystallized polymer have been investigated by NMR and dynamic mechanical techniques. Dynamic mechanical data for crystal mats of P4MP1 were obtained with a vibrating reed apparatus by J. A. E. Kail of Imperial Chemical Industries, Ltd., Plastics Division, on a... 

The vibration or twanging of a platinum loop used for the inoculation of a culture of organisms can also generate an aerosol and this technique is used to advantage in the vibrating reed aerosol generator which is capable of generating a monodisperse aerosol. 

With vibrating or oscillating techniques, the change of mass of a polymer sample is calculated from the resonance characteristics of a vibrating support, either a piezoelectric crystal [9, 10] or a metal reed [11], to which the polymer sample is fixed (very often this support is a spherical quartz resonator on which a thin polymer film is wrapped). Depending on the type of oscillator, the maximum pressure can be between 15 and 30 MPa. 

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