This paper reports a tunable visual color filter based on a microfluidic transmission grating. The grating lines are formed by the microflows in an array of evenly spaced straight microchannels. In experimental study, the transmission of white light measures a shift of visual color from red to blue in the zeroth order diffraction in response to a change of the refractive index from 1.3290 to 1....

This paper reports new results regarding the usefulness of colour measurements in flotation process. Colour measurements coming simultaneously from RGB-camera and a spectrophotometer (and from the same measurement point) are compared. The measured variables are used to construct a partial least squares (PLS) model and a multilinear regression (MLR) model for the prediction of the zinc content i...

Serum alkaline phosphatase estimations by the Selected Method [Clin. Chem. 21, 1988 (1975)] are very sensitive to small errors in the wavelength setting of the spectrophotometer. With a setting error as small as 3 nm, results can be too low by as much as 23%. The product of the reaction, 4-nitrophenol, can be prepared in very pure form and can be used to check both the wavelength and absorbance...

This paper describes a robust and rapid procedure for measuring chlorophyll using a microplate reader. The procedure enables direct translation of any published equation developed on a 1-cm pathlength spectrophotometer to any format microplate with any sample volume. Chlorophylls were extracted with methanol because it is compatible with cheap polystyrene plates; however, the principles apply t...