Search results for "Colori"

The b-chromatic number of power graphs

2003

The b-chromatic number of a graph G is defined as the maximum number k of colors that can be used to color the vertices of G, such that we obtain a proper coloring and each color i, with 1 ≤ i≤ k, has at least one representant x_i adjacent to a vertex of every color j, 1 ≤ j ≠ i ≤ k. In this paper, we discuss the b-chromatic number of some power graphs. We give the exact value of the b-chromatic number of power paths and power complete binary trees, and we bound the b-chromatic number of power cycles.

Detection and discrimination of organophosphorus pesticides in water by using a colorimetric probe array

2014

[EN] Detection and discrimination of several organophosphorus pesticides in water using a colorimetric probe array containing twelve dyes has been achieved. A clear discrimination for malathion, leptophos, dichlorvos, dibrom and diazinon was observed. The array was used to determine the concentration of diazinon in orange leaves

Colour assessment of milk and milk products using computer vision system and colorimeter

2021

Abstract A computer vision system (CVS) and a colorimeter were compared for their abilities to measure the colour of twenty-seven different milks and milk products. The frequency of similarity test showed that CVS-generated colour chips were similar to the actual sample colour in all trials (100%). The CVS-obtained colours were found to be more similar to the colour of sample visualised on the monitor, compared with colorimeter-generated colour chips, with values of 83.3–100.0% depending on the milk product. The third test showed that there was difference between colour measured by CVS and the colorimeter; colorimeter readings resulted in a darker and yellower colour based on average L∗a∗b∗…

Application Of Anamorphic Systems To Directional Pseudocolor Encoding

1988

An optical nonsymmetrical imaging system composed of two anamorphic spectrum analyzers in cascade is implemented. This system can provide an undistorted final image in spite of the geometrical distortion effects in the intermediate Fourier plane. The introduction of chromatic sector filters in this plane provides a real-time technique to pseudocolor encode the spatial frequency information of a black-and-white transparency. In this way, greater discrimination is achieved in the angular orientation of object details that generate the same spatial frequencies. Experimental pseudocolored images, obtained with a symmetrical system and a nonsymmetrical system, of a black-and-white transparency a…

Characterization of a digital camera as an absolute tristimulus colorimeter

2003

An algorithm is proposed for the spectral and colorimetric characterization of digital still cameras (DSC) which allows them to be used as tele-colorimeters with CIE-XYZ color output, in cd/m2. The spectral characterization consists in the calculation of the color-matching functions from the previously measured spectral sensitivities. The colorimetric characterization consists in trans- forming the raw RGB digital data into absolute tristimulus values CIE-XYZ (in cd/m2) under variable and unknown spectroradiometric conditions. Thus, in the first stage, a gray balance was applied over the raw RGB digital data to convert them into RGB relative colorimetric values. In the second stage, an algo…

Retracted Article: Differential detection and quantification of cyclic AMP and other adenosine phosphates in live cells

2017

A new naphthol-based rhodamine derivative (NpRD) has been developed for the selective and differential detection of adenosine 3′,5′-cyclic monophosphate (cAMP) and adenosine phosphates (APs) (ATP, ADP, and AMP) from other nucleotides. The simple detection and quantification of cAMP in human blood cells and in other samples based on the ‘turn on’ fluorescence properties of this chemosensor through colorimetry or fluorometry makes it unique for probable application in high throughput screening.

Influence of the presence of surfactants and humic acid in waters on the indophenol-type reaction method for ammonium determination.

2005

Abstract This work has evaluated the influence of humic acid and/or surfactants in the quantification of ammonium in waters with the indophenol-type reaction method. Thymol has been employed with the colorimetric method for sample ammonium concentrations between 0.25 and 1 mg L −1 . In addition, SPE/diffuse reflectance method has been used for quantification of ammonium at low concentrations (between 0.025 and 0.25 mg L −1 ). Matrix effect owing to humic substances were observed with the colorimetric method when the concentration was equal or higher than 25 mg L −1 . Lower concentrations of humic compounds produced matrix effects with the more sensitive SPE/diffuse reflectance method. Gener…

Supramolecular organic-inorganic hybrid assemblies with tunable particle size: interplay of three noncovalent interactions.

2013

Chemical Approach to Functional Artificial Opals

2007

Artificial opals are self-assembled colloidal crystals, which consist of a cubic dense packing (fcc) of hard (not film-forming) colloids with diameters ranging from 200 to 900 nm. Because of their periodic nanostructure the assemblies are able to reflect light that matches their periodicity, i.e., UV- to IR-radiation depending on the size of the colloids. Thus, they present a subgroup of 'photonic crystals'. While, originally, the chemistry inside the colloids and the resulting opals was of minor significance, nowadays the chemical variation of opals is becoming more and more important for the preparation of functional and patterned opals. The search for functional opals is, therefore, espe…

Die herstellung einiger gekennzeichneter, aliphatischer azoverbindungen und ihre anwendung als initiatoren der polymerisation

1970

Es wird die Herstellung von vier Azoverbindungen beschrieben, die sich zum Teil vom α.α′-Azo-(isobuttersaurenitril) ableiten. Zwei Verbindungen geben bei der Polymerisation von Methacrylsauremethylester und Styrol Endgruppen, die in den Polymeren photometrisch leicht zu bestimmen sind; fur eine wird gezeigt, das sie die Polymerisation von Styrol startet, ohne das storende Nebenreaktionen auftreten. Die beiden anderen Azoverbindungen sind wegen ihrer hohen Zersetzungspunkte geeignet, radikalische Polymerisationen bei hoheren Temperaturen auszulosen (160°C). The preparation of four derivatives of α.α′-azo-bis-isobutyronitrile is described. The polymerization of methylmethacrylate and styrene …