scholarly journals Structural Layers Origin Of The Blue Colour Reflections On The Wings Of The Junonia Orithya Madagascarensis

2016 ◽  
Vol 12 (24) ◽  
pp. 147
Author(s):  
Issaka Ouedraogo ◽  
Emmanuel Nanema ◽  
Bintou Ouedraogo ◽  
Alioune Ouedraogo ◽  
Priscilla Simonis ◽  
...  
Keyword(s):  
Reflectance Spectrum ◽  
Main Peak ◽  
Nanometer Scale ◽  
Blue Color ◽  
Artificial Reproduction ◽  
Blue Colour ◽  
Selective Reflection ◽  
Structural Coloration ◽  
Structural Nature

This article is devoted to the study of the structural layers origin of the blue reflections on the scales of the wings of the Junonia orithya madagascarensis, a butterfly of the Nymphalidae species. We proceed by spectrophotometry and scanning electron microscope (SEM) characterization of these layers to explain the origin of the blue color of the wings. We also made numerical calculations to simulate the structural nature of these layers which help to support the experimental results. Indeed, from the measurements using the spectrophotometer, a main peak of reflection was obtained at 483 nm. From our calculations results we get a 515 nm for the dominant length in reflection and 510 nm for the numerical reproduction of the reflectance spectrum, respectively. These results confirm that the multilayer structure is at the origin of the blue colour of the dorsal scales of the wings of the Junonia. A very thin membrane is responsible for it. This membrane diffuses sunlight at its upper and inner surface. Therefore, it is called structural coloration. It is possible to consider artificial reproduction for the multilayer through a process of deposits in order to manufacture materials at nanometer scale with selective reflection.

scholarly journals Reflectance Spectrum of a Color Blue Generated by Curved Multilayer and Iridescent of the Elytron of the Calidea Signata Bug

2016 ◽  
Vol 12 (36) ◽  
pp. 1
Author(s):  
Issaka Ouedraogo ◽  
Serge Wendsida Igo ◽  
Priscilla Simonis ◽  
Alioune Ouedraogo ◽  
Belkacem Zeghmati
Keyword(s):  
Multilayer Structure ◽  
Reflectance Spectrum ◽  
Main Peak ◽  
Blue Color ◽  
Transfer Matrices ◽  
Microscopy Characterization ◽  
Two Peaks ◽  
Second Peak ◽  
Scanning Electron Microscopy Characterization ◽  
Scanning Electron

This paper focuses on the study of the origins of blue iridescent reflections of the elytron of Calidea Signata, of the pentatomidae family which is commonly known as bug. Indeed, we use the spectrophotometry measurements, scanning electron microscopy characterization technique, and a ray tracing code program combined with the transfer matrices method, to explain the structure which is responsible for the color of the blue reflections and the iridescent effect. Thus, we noticed that the color of the bug as a result of two peaks. The first and main peak is located at 485.5 nm, corresponding to the blue color. The second peak, is less intense at 525 nm, corresponding to the green-blue color. The numerical reproduction of the reflectance spectrum gives 510.25 nm for the main peak, and 539.5 nm for the secondary peak. These results confirm that the multilayer structure is responsible for the blue color of the Calidea Signata bug. Lastly, the curve of the multilayer is responsible for the iridescence.

scholarly journals Identification of pigments in artworks by inverse tangent derivative of spectrum and a new filtering method

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
F. Fazlali ◽  
S. Gorji Kandi
Keyword(s):  
Reflectance Spectrum ◽  
Practical Method ◽  
Chemical Methods ◽  
Munk Function ◽  
Absorption Of Light ◽  
Spectrophotometric Data ◽  
First Time ◽  
Non Destructive ◽  
Derivatives Of

Abstract Employing an economical and non-destructive method for identifying pigments utilized in artworks is a significant aspect for preserving their antiquity value. One of the non-destructive methods for this purpose is spectrophotometry, which is based on the selected absorption of light. Mathematical descriptive methods such as derivatives of the reflectance spectrum, the Kubelka–Munk function and logarithm have been employed for the characterization of the peak features corresponding to the spectrophotometric data. In the present study, the mentioned mathematical descriptive methods were investigated with the aim to characterize the constituents of an Iranian artwork but were not efficient for the samples. Therefore, inverse tangent derivative equation was developed on spectral data for the first time, providing considerable details in the profile of reflectance curves. In the next part, to have a simpler and more practical method it was suggested to use filters made up of pure pigments. By using these filters and placing them on the samples, imaging was done. Then, images of samples with and without filter were evaluated and pure pigments were distinguished. The mentioned methods were also used to identify pigments in a modern Iranian painting specimen. The results confirmed these methods with reliable answers indicating that physical methods (alongside chemical methods) can also be effective in determining the types of pigments.

scholarly journals Scattering of light by dust-free air, with artificial reproduction of the blue sky.—Preliminary note

1918 ◽  
Vol 94 (662) ◽  
pp. 453-459 ◽  
Keyword(s):  
Sea Level ◽  
Suspended Particles ◽  
Artificial Reproduction ◽  
Blue Colour ◽  
Foreign Matter ◽  
Preliminary Note ◽  
Scattering Of Light ◽  
Free Air

It is now well established that the luminosity and blue colour of the sky on very clear days and at considerable altitudes above the sea-level can almost be accounted for by the scattering of light by the molecules of air, without postulating suspended particles of foreign matter, such as were thought necessary by the earlier writers. This conclusion depends on the measured opacity of the atmosphere, deduced from observations such as those of Abbot and Fowle of the sun’s radiation at various zenith distances. The opacities measured at Mount Wilson for different wave-lengths are found to be nearly in agreement with what would be expected if scattering by the molecules were alone operative; leaving little room for the action of larger particles.

The Experimental of Low Temperature Color Slip for Decorative on Earthenware Body

2016 ◽  
Vol 690 ◽  
pp. 282-285
Author(s):  
Soravich Mulinta
Keyword(s):  
Low Temperature ◽  
Physical Properties ◽  
Manganese Oxide ◽  
Ferric Oxide ◽  
Potassium Feldspar ◽  
Raw Material ◽  
Blue Color ◽  
X Ray ◽  
Yellow Color

The purpose of the study was to investigate the effects of dolomite body, frit and potassium feldspar on the properties of color slip for decorative method of color slip on earthen ware production. The characterization of raw material was analyzed by X-ray fluorescence (XRF). The experiment started with triaxial blend of dolomite body, frit and potassium feldspar in the defined ratio and then to painting of color slips on earthenware production. After that, firing specimens at 950 °C in oxidation atmosphere. Finally, the specimens were tested microstructure and physical properties. The results showed that the ratio of 50% dolomite body, 40% frit and 10% potassium feldspar were optimum properties for decorative on earthenware body. In color slip consisting of blue color added Cobalt oxide 1% ,Green colors added chromic oxide 10% , Gray color added manganese oxide 10% ,yellow color added stain 2225 10% and hazel color added ferric oxide 2 wt %.

scholarly journals Characterization of native and oxidized starches of two varieties of Peruvian carrot (Arracacia xanthorrhiza, B.) from two production areas of Paraná state, Brazil

2009 ◽  
Vol 52 (3) ◽  
pp. 701-713 ◽  
Author(s):  
Luciana Shizue Matsuguma ◽  
Luiz Gustavo Lacerda ◽  
Egon Schnitzler ◽  
Marco Aurélio da Silva Carvalho Filho ◽  
Célia Maria Landi Franco ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Reducing Power ◽  
Blue Color ◽  
Carboxyl Content ◽  
Modified Starches ◽  
Physicochemical Methods ◽  
Partial Degradation ◽  
Almost All ◽  
Production Areas

Two commercial varieties of Peruvian carrot ('Amarela de Carandaí' and 'Senador Amaral') were processed into flour, starch and bagasse and chemically evaluated. The starch was extracted, modified with H2O2 and characterized by the physicochemical methods. By using the methylene blue dyeing, the granules of the modified starches showed intense blue color. The carboxyl content, the reducing power and the amount of the water liberated from the pastes after the freeze-thawing were higher for the oxidized starches and their pastes were clearer than those of the native starches of the two varieties from the two production areas. The RVA viscoamylography showed that the modified starches had lower viscosities with differences between the varieties. In the thermal analysis, the temperatures of the pyrolysis were higher for the native (310.37, 299.08, 311.18 ºC) than for the modified starches (294.16, 296.65 e 293.29 ºC) for both the varieties. This difference could be related with the larger surface of the granules due to the partial degradation promoted by the chemical modification. In almost all results, the differences were evident between the varieties but not for the cultivation places.

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