Outer noise

Outer noise - environmental eonditions sueh as temperature, humidity, different eustomer usage... 

Outer noise - environmental variables that affect the performance of a product. For example temperature, dust, humidity. 

COMPRESSOR WILL NOT START 1. Power supply failure. 2. Switchgear or starting panel. 3. Low oil pressure shut down switch. 4. Controi panel. NOISE IN CYLINDER 1. Loose piston. 2. Piston hitting outer head or frame end of cylinder. 3. Loose crosshead lock nut. 

Because of their cellular or open-matrix construction, most insulants have an inherent ability to absorb sound, act as panel dampers and reduce noise breakout from plant by their ability to be a flexible or discontinuous link between an acoustically active surface and the outer cladding. This secondary aspect of thermal insulation specification will gain more prominence when the UK adopts the EC Directive 86/1888, Protection of workers from the risks related to exposure to noise at work . 

Fig. 12b). Since practically the same spectral shape is obtained at Q-band (35 GHz) (Fig. 12c), the commonly used criterion stating that the shape of an interaction spectrum is frequency-dependent fails to apply in this case. Actually, outer lines arising from the exchange interaction are visible on the spectrum calculated at Q-band (Fig. 12c), but these lines would be hardly detectable in an experimental spectrum, because of their weak intensity and to the small signal-to-noise ratio inherent in Q-band experiments. In these circumstances, spectra recorded at higher frequency would be needed to allow detection and study of the spin-spin interactions. 

Taguchi uses fractional factorial designs to determine the first-order effects of both the control factors and the noise factors, but he separates the factors and the designs into an inner array (involving the control factors only) and an outer array (involving the noise factors only). The concept is shown geometrically in Figure 14.8 for three control factors and three noise factors. 

Figure 14.8. The inner array exists in the three-dimensional space of control factors x X2, and X3 these might represent temperature, flow rate, and pH, respectively. The outer array is represented by the small fractional factorial designs shown at each factor combination of the inner array. It is important to understand that this inner outer does not exist in the control factor space - it exists in a separate three-dimensional space of noise factors, designated for our purposes here as z Zj, and Z3 these might represent ambient humidity, source of raw material, and identity of process operator.

Suppose viscosity, y, is the quality response of interest. Then at one of the four factor combinations in the inner array (i.e., in the control factor space), experiments can be carried out at the four factor combinations in the outer array (i.e., in the noise factor space). Frequently the outer array experiments are adventitious experiments in the sense that the experimenter has to wait until, say, the ambient humidity approaches the desired value then the appropriate source of raw material and the appropriate process operator can be brought in and the experiment can be carried out. 

Taguchi realized that the effects of the noise factors might depend on the settings of the control factors. The four experiments of the outer array described in the... 

The relative intensities of the lines within each multiplet will be in the ratio of the binomial coefficients (Table 5.9). Note that, in the case of higher multiplets, the outside components of multiplets are relatively weak and may be lost in the instrumental noise, e.g. a septet may appear as a quintet if the outer lines are not elearly visible. The intensity relationship is the first to be significantly distorted in non-ideal cases, but this does not lead to serious errors in speetral analysis. 

From these two orthogonal arrays a cross-product design is constructed (see Table 4.2 for an example), for each setting of the control factors in the inner array the complete noise factor (outer) array has to be executed to determine the effect of the environmental factors. 

For a Taguchi approach to robustness the solvent composition is varied in the inner array, and the relative humidity and temperature in the outer array. The response is the resolution of noscapine and quinine. The data used in this example is a subset of the data set which is collected for this paper. The inner array consists of seven design points, the outer array of three. The three responses obtained at each setting of the inner array are combined to form a so-called signal-to-noise ratio. For maximization of the responses the following equation is [11] ... 

Each run of this matrix (inner array) is repeated nine times (outer array), following a CFD 3, for both noise factors. After all experiments were made in the laboratory, calculations were done to refer the concentration of the slurry extracts to the original sample. They are shown in Table 2.15. 

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