Mechanical quality factor

FIG. 10-164 Longitudinal and spiral-weld joint factor E. NOTE It is not permitted to increase tlie joint quality factor by additional examination for joints 1, 2, and 4a. (EjLtracted from ANSI B31.3—19S0, with petmission of the publisher, theAmetican Society of Mechanical Engineets, New York.)... 

Abstract The self-organized and molecularly smooth surface on liquid microdroplets makes them attractive as optical cavities with very high quality factors. This chapter describes the basic theory of optical modes in spherical droplets. The mechanical properties including vibrational excitation are also described, and their implications for microdroplet resonator technology are discussed. Optofluidic implementations of microdroplet resonators are reviewed with emphasis on the basic optomechanical properties. 

Mechanical quality factors Resistance to failure V V V Tensile strength... 

The information about the losses in the material under investigation lies within the unloaded quality factor. In case of measurements at low levels of rf power weak coupling (Qexti, Qext2 Ql) resulting in Qo Ql is of common use. For measurements of the power dependence matched input coupling (Qexti Qo) and weak output coupling conditions should be adjusted (e.g. by a mechanical adjustment of coupling antennae position inside a cavity resonator). 

Provided that the mechanical quality factor (see Fig. 5.34 for analogy) for the resonator is sufficiently high (Qm 100) the approximations apply. 

According to this definition, the quality of mechanical or electrical energy is equal to unity and that of thermal energy at a temperature, T, is equal to the Carnot factor, 1 - TQ/T. For chemical reactions, the exergy ratio (a-) represents that fraction of the delivered energy that could be converted to thermodynamic work by a reversible process and has a value most often (but not always) between zero and unity. 

A major degradation mechanism of modules is the decrease in fill factor. This is caused by an increase in the diode quality factor of the cells making up the module and by an increase in series resistance. The former is related more to the absorber and heterojunction properties and less to the ZnO properties. The series resistance increases because the conductivity of the ZnO drops and because the interconnects are deteriorating. Wennerberg et al. have assessed the individual contributions to increased series resistance [50]. Klaer et al. [52,53] have described a transmission-line test structure that allows to separate the contributions of contact and sheet resistance, respectively. The test structure is prepared by the same scribing techniques as those used in module manufacturing. 

The quality factor, or Q-factor, is a general dimensionless parameter, used in mechanical, electrical, electromagnetic, and optical contexts. Given some signal intensity S(co) as a function of frequency m, the Q-factor is defined as the resonance frequency divided by the bandwidth A (see Fig. 9.4) ... 

Second, we use an additional set of provided buried electrodes to stimulate an out-of-plane (see-saw) motion on the device level. From the drive voltage and the corresponding signal response of this BITE, we could calculate the electrical sensitivity if the mechanical sensitivity were known. However, the mechanical sensitivity is not directly accessible and is therefore calculated from in-plane and out-of-plane resonance frequencies and the in-plane quality factor. 

This approach to a quadrature test comprises acquisition of 7 directly accessible electrical measurands and a 5-step modeling sequence. As a multiple functional parameter test of considerable breadth and expense, it delivers control of resonant quality factors, rate offsets, and mechanical and electrical sensitivities, in addition to quadrature-induced offsets. 

There are various operation modes for piezoelectric sensors, depending on the crystallographic orientation of the plate and the material [1]. These modes include transversal compression, thickness or longitudinal compression, thickness shear action and face shear action. Also available are piezoelectric polymeric films, which are very thin, lightweight and pliant, such as polyvinylidene fluoride (PVDF) [3,4]. These films can be cut easily and adapted to uneven surfaces. Resonance applications are not possible with PVDFs because of their low mechanical quality factor. However, they can be used in acoustical broad-band applications for microphones and loudspeakers. 

Compliance is the reciprocal of the modulus and favored by some scientists, and the ceramicists have used Q, the mechanical quality factor or cot delta (= 1/ tan 5). 

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