Noise isolation pads

The other major source of noise is vibration from the environment. The entire measuring system is, of course, mounted on appropriate rubber isolation pads. However, these are not adequate for the level of accuracy required. The residual vibration is eliminated from the signal by mounting the lower part of the optical reflection system on a spring which is driven by servo electronics that detects its movement. An effective free period for the spring of up to 60 s can be achieved in this way, and virtually all environmental vibration is eliminated from the measured signal. 

A pn-junction layer 1 of HgCdTe, which has a passivation layer 12, is bonded to a silicon multiplexer chip 2 by a bonding layer 4. The lower layer 9 of the heterojunction I is p-type and the upper layer 10 is n-type. Holes 8 are ion-etched right through the semiconductor layer to contact pads 6. The regions of the layer 9 forming the walls of the holes are converted to n-type by the ion beam. A homojunction is thus formed in parallel with the heterojunction. The compositions are selected so that the heterojunctions determine the infrared response and noise characteristics and the homojunctions act as noiseless isolation devices. 

Sanitary protection industry can be broadly classified into three main categories sanitary pads, tampons, and menstmal cups. Functions of sanitary napkins are to absorb and retain menstmal fluid and isolate menstmal fluids from the body. Important/ desired properties are no leakage, no unaesthetic appearance or colour, no odour, no noise, stay in place, comfortable to wear (thin body shape), hygiene. 

These screens are set at an angle with respect to the horizontal. The vibration occurs at a right angle to the screen by the rotation of unbalanced counterweights on a shaft above the screen. Vibration can also be induced by electromagnets and oscillating currents. Vibration levels are high and the screens must be mounted on vibration isolation rubber pads. These screens are extremely noisy and exceed 100 dBA levels of noise, nevertheless, they are the most widely used. 

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