Multi-angle measurements

The resolution of PCS can be improved by the simultaneous analysis of data collected at more than one scattering angle, combined with the 

Multi-angle instruments are also available to generate the angular variation of scattered light intensity for derivation of molecular weight, radius of gyration, translational and rotational diffusion coefficients and other molecular properties [300]. 

Beckman/Coulter N4 Plus Fiber optics multi-angle 

Otsuka Photol DLS-700 (Munhall) Fiber optics multi-angle 

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In a plot of K c/R(Q) vs. sin2(0/2), Mw can be obtained from the intercept and the radius of gyration from the slope. A multi-angle measurement provides additional information. 

Recent advances have greatly decreased the difficulties raised by these cautionary points. In particular, on-line viscosimetry and multi-angle lightscattering make it possible to determine the molecular weight and viscosity of samples as a function of elution volume. With such detectors, effects of solute-column packing interactions become unimportant, since the properties of narrow fractions can be measured. These detectors will be discussed in greater detail below. 

Organic carbon (OC) and elemental carbon (EC) concentrations in smoke aerosol can be measured by using a semicontinuous thermal-optical OC/EC instruments [18]. Water-soluble organic carbon (WSOC) and water-soluble ions can be detected in smoke plumes with a PILS combined with a total organic carbon analyzer [30] and IC [19]. Besides smoke-specific tracers, the HR-ToF-AMS enables to study the concentrations of organic matter (OM), nitrate, ammonium, sulfate, and chloride in smoke particles [30]. Black carbon (BC) can be measured in real-time with several instruments, e.g., with aethalometer [19], multi-angle absorption photometer [29], and particle soot absorption photometer [25]. 

Multi-angle PCS was also preferred by Bryant et.al. [320,321] for measuring multi-modal PSD s, and they showed that accuracy increased with increasing number of angles. 

The parameter Ir lf at a given value of 9 is called the Rayleigh ratio, Rq. Modern multi-angle laser light scattering equipment (MALLS) simultaneously measures scattered intensity at several values of 9. Therefore, a typical static light-scattering experiment involves the measurement at a matrix of values of 9 and c the polymer concentration. 

In many remote-sensing applications the number of measurements Nf exceeds the number of retrieved parameters This is characteristic of new advanced sensors with multi-spectral, multi-angle [20-23, etc.], and polarimetric... 

When considering an instrument for color measurement three main geometries of color instrumentation need to be reviewed. These are the 0/45, or 45/0 sphere (d/8) and multi-angle. Each geometry is designed to measure specific samples for color of color and appearance attributes. 

Reduction in standard variation can be investigated by using the multi-angle spectrophotometer and one of the following measurement methods. The first is to have a single standard that paint suppliers, assembly plants and other part suppliers all can measure. They each measure the one standard, usually iixtured, and retain the numerical value of that standard measured by their multi-angle spectrophotometer. 

Multi-angle color measurement is an essential tool in identifying and reducing color variation in processes that use metallic, pearlescent and special effects color. There are also several options available in using the instrument to reduce the variation amongst standards, the key be-... 

In 1994, we decided to evaluate a multi-angle spectrophotometer from X-rite Incorporated, to see if the instrument would be able to measure and thus better characterize what we see visually. We felt that if we could measure color at the flop angles we could compare various submissions and formulate better matches with regards to both flop and color travel. 

When we started this work, we had hoped to address the correlation of illumination/mea-surement geometry for the multi-angle instrument versus the visual evaluation conditions. This was suggested to us by the fact that we had customers with different conditions for visual assessment as many molders still utilize the conventional light booth. The two systems have different illumination geometiys and intensity levels and we have seen this affect visual assessment in the past. This work would require precise measurement of the angles involved and we concluded this was beyond the scope of our work. In the end, we came to view the multi-angle unit as a tool to measure differences and help us correct those that we saw as visually important. ... 

We studied the effect of texture on multi-angle readings by measuring various textures of OEM master plaques. Not surprisingly, texture which effects the way light is reflected... 

Gloss, texture and measurement orientation can produce large differences in readings obtained from the multi-angle spectrophotometer. Care must be taken to make sure that samples are comparable for texture and gloss. Even though this is not always as easy as it sounds. 

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