Mechanical noise

Cleveland J P, Schaffer T E and Hansma P K 1995 Probing oscillatory hydration potentials using thermal-mechanical noise in an atomic force microscope Rhys. Rev. B 52 R8692-5... 

To do this, the tower is therefore connected, through a 25 cm copper bar passing through the mixing chamber, to a stainless steel spring fixed at the 50 mK plate. This experimental configuration has appreciably reduced the mechanical noise on the detectors... 

The detection limit is generally limited by electronic and mechanical noise, thermal drift, light source instabilities and chemical noise. But the intrinsic reference channel of the interferometric devices offers the possibility of reducing common mode effects like temperature drifts and non-specific adsorptions. Detection limit of 10 in refractive index (or better) can be achieved with these devices which opens the possibility of development of highly sensitive devices, for example, for in-situ chemical and biologically harmful agent detection. 

Additionally, if the engine cooling system fails to effectively remove heat from the combustion chamber, knock may result. Also, at high speeds, knock can also occur, but may go unnoticed due to mechanical noise from the engine. 

B. Mechanical noise Is produced by the functioning of the weapon upon... 

Some noise also escapes through the unlocked breech area of these autos. A bolt action rMie will produce little if any mechanical noise when fired and no sound escapes from the breech area. 

The basis of this unit is a Ruger RST 22 autopistol with a 4-3/4 barrel. The Ruger was chosen for both its reliability.and relatively low mechanical noise. An earlier version of this design was used by the OSS in W 14 II and is still available to CXA and National Security Agency NSA personel. This early version was built on a High Standard pistol and contained a compressed stack of brass screen washers instead of threaded copper and fiberglass. 

Optical interferometer techniques can achieve resolution far beyond 1 nm. Because of this high sensitivity of the interferometer sensor, the direct detection of small molectdes at low concentrations should be possible [15]. Detection is generally limited by electronic and mechanical noise, thermal drift, light source instabilities, and chemiced noise. But interferometric devices have an intrinsic reference channel which ofiers the possibility of... 

The main apparent technical problems posed in relation with these types of potential noise barriers would be their noise abatement capability, structural performance, fire resistance, weatherability, chemical activity, and environmental effects. To assess the quality of new products of such materials, a series of mechanical, noise abatement, and flammability tests should be performed on a number of samples from the panels made of recycled rubber products. The primary function of these panels, i.e., their noise abatement capability is among the most important aspect of their performance. 

Finally, mechanical noise is the result of Brownian motion of gases around the proof mass. This noise component can be described by... 

Signals from the transducers and microphones are amplified, filtered, and analyzed. Typically, charge amplifiers are used for the microphones, and voltage amplifiers, for the transducers. High-pass filters are applied to the signals to eliminate low-frequency mechanical noise, such as pipe vibration. The signals are analyzed by either a true RMS voltmeter or a wide-band spectrum analyzer. 

Regarding the D.I. engines, noise reduction occurs through mechanical and combustion improvements. For mechanical noise the piston slap phenomenon (a vibration created by the piston to cylinder shock when the piston travels, near T.D.C., from left to riglit) decreases after better adjustment of clearance, shape... 

Likewise, mechanoreceptors in the skin can be made more sensitive by applying a small-amplitude random signal (Figure 8.2.21). By itself, this electrical or mechanical noise is less than the sensor threshold, and not detectable. When added to a small primary signal, however, some of the noise pulses exceed the threshold, and the sensor fires. Thus, the magnitude of the adequate stimulus has been made smaller. 

The mechanical properties of the tip-cantilever assembly are of central importance. Caused by the forces effective between the surface and tip, the cantilever is deformed. This deformation controls the overall performance of the microscope. The spring constant k and the resonance frequency coq of the cantilever are particularly important. In order to be insensitive to mechanical noise from the environment, a high... 

Mechanical problems in NIR instrumentation can be a real problem, especially for online instiument-ation where environmental noise may defect our ability to hear audible noise that would normally be detected in a quiet laboratory. Mechanical noise, causing the lamp filament to vibrate, can be transferred to the spectrum. Information in the Fourier spectrum is a good indicator of this type of noise. Because the power spectrum is easily computed from the following ... 

Figure 6.15a and Figure 6.15b gives the power spectrum of two Comp/Specs. Both systems were constructed identically. However, on examination of the power spectra of the two instruments a noise peak at index 757 was discovered for instrument 1, a peak that did not appear in the power spectrum of instrument 2. The peak at index 757 corresponds to a noise frequency of 4.8 Hz, a mechanical noise problem in one of the gears of the instrument. 

Dickinson MH. (1990) Linear and nonlinear encoding properties of an identified mechanoreceptor on the fly wing measured with mechanical noise stimuli. J Exp Biol 151 219-244. 

Downsizing the cantilever structure to a microscopic size results in fast response times at high sensitivity and a high resonant frequency, additionally such sensors are quite immune to external mechanical noise. 

Electromagnetic-mechanical noise from parasitic forces, which are caused by flux and current harmonic interactions, produce mechanical vibrations within the motor and contribute to an overall increase in sound power levels. This mechanism will usually become a problem when amplifled by mechanical resonances in the motor... 

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