scholarly journals Analysis of red chalk drawings from the workshop of Giovanni Battista Piranesi using fiber optics reflectance spectroscopy

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Maria Krämer ◽  
Ute Henniges ◽  
Irene Brückle ◽  
Laura Lenfant ◽  
Kirsten Drüppel
Keyword(s):  
Electron Microscopy ◽  
Fiber Optics ◽  
Principal Component ◽  
Reflectance Spectroscopy ◽  
Spectral Features ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Town ◽  
Scanning Electron ◽  
Historical Samples

AbstractThe viability of fiber optics reflectance spectroscopy (FORS) for the differentiation of red chalk drawing media was investigated, focusing on the group of drawings from the workshop of Giovanni Battista Piranesi (1720–1778) at the Staatliche Kunsthalle Karlsruhe, Germany. The evaluation of spectra was supported by principal component analysis (PCA). The method was tested on mock-up drawings made with recently acquired natural and synthetic red chalks of known origin. It was possible to sort these mock-up drawings according to chalk type and application technique. The compositional differences of these reference chalks were confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Subsequent FORS analysis of selected original drawings revealed the existence of several closely grouped clusters, implying similarities on the basis of the underlying spectral features among the historical red chalks used in Rome. These similarities distinguished the historical drawings from the red chalk mock-up drawings, except for the drawings made with red chalk samples from the area near the town of Theley, Germany, which were shown to bear close similarities to those in the cluster of historical samples.

scholarly journals Analysis of Red Chalk Drawings from the Workshop of Giovanni Battista Piranesi using Fiber Optics Reflectance Spectroscopy

2021 ◽  
Author(s):  
Maria Krämer ◽  
Ute Henniges ◽  
Irene Brückle ◽  
Laura Lenfant ◽  
Kirsten Drüppel
Keyword(s):  
Electron Microscopy ◽  
Fiber Optics ◽  
Principal Component ◽  
Reflectance Spectroscopy ◽  
Spectral Features ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Town ◽  
Scanning Electron ◽  
Historical Samples

Abstract The viability of fiber optics reflectance spectroscopy (FORS) for the differentiation of red chalk drawing media was investigated, focusing on the group of drawings from the workshop of Giovanni Battista Piranesi (1720–1778) at the Staatliche Kunsthalle Karlsruhe, Germany. The evaluation of spectra was supported by principal component analysis. The method was tested on mockup drawings made with recently acquired natural and fabricated red chalks of known origin. It was possible to sort these mockup drawings according to chalk type and application technique. The compositional differences of these reference chalks were confirmed by X-ray diffraction and scanning electron microscopy. Subsequent FORS analysis of selected original drawings revealed the existence of several closely grouped clusters, implying similarities on the basis of the underlying spectral features among the historical red chalks used in Rome. These similarities distinguished the historical drawings from the red chalk mockup drawings, except for the drawings made with red chalk samples from the area near the town of Theley, Germany, which were shown to bear close similarities to those in the cluster of historical samples.

Synthesis and photocatalytic performance of Bi2S3/SnS2 heterojunction

2017 ◽  
Vol 10 (02) ◽  
pp. 1750004 ◽  
Author(s):  
LiZhen Ren ◽  
DongEn Zhang ◽  
Xiao Yun Hao ◽  
Xin Xiao ◽  
Jun Yan Gong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Diffuse Reflectance ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Reflectance Spectroscopy ◽  
Simulated Sunlight ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Bi2S3/SnS2 heterostructured photocatalysts were synthesized from BiOI, SnCl[Formula: see text]5H2O and NH2CSNH2 using an economic and simple hydrothermal method. The as-synthesized samples were characterized by X-ray diffraction, scanning electron microscopy and ultraviolet-visible diffuse reflectance spectroscopy. The photodegradation activities of the Bi2S3/SnS2 heterostructured photocatalysts were estimated by degrading rhodamine B under simulated sunlight supplied by irradiating with a 350[Formula: see text]W Xe lamp. Bi2S3/SnS2 photocatalysts were prepared using varying percentages of Bi2S3. The sample containing 13% Bi2S3 had the most efficient photocatalyst performance among the tested samples. The photocatalytic mechanism involves heterojunctions formed in the Bi2S3/SnS2, which promoted effective separation of photoinduced electrons and holes.

Vacuum Pressure MOVCD Growth and Characterization of AlN Films On MgO(100), Sapphire, and Si

1997 ◽  
Vol 482 ◽  
Author(s):  
A. D. Serra ◽  
N. P. Magtoto ◽  
D. C. Ingram ◽  
H. H. Richardson
Keyword(s):  
Electron Microscopy ◽  
Reflectance Spectroscopy ◽  
Vacuum Pressure ◽  
Ex Situ ◽  
Infrared Reflectance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Substrate Temperatures ◽  
Scanning Electron

abstractFilms of AlN were grown on MgO(100), Al2O3, and Si under vacuum pressure (10-3 to 10-4 Torr) at different substrate temperatures. They were examined ex situ with infrared reflectance spectroscopy, scanning electron microscopy, x-ray diffraction and rutherford backscattering spectroscopy. Highly oriented smooth films were grown at film thicknesses below 1 μm. Thicker films showed significantly more roughness but remained oriented with respect to the substrate. AIN growth was faster on Si than MgO(100) or Al2O3 and Si was the only substrate that growth was observed at 500°C.

Sonochemical Decolourisation of Reactive Blue 21 and Acid Red 114 in the Presence of TiO2 and Rare Earths

2012 ◽  
Vol 734 ◽  
pp. 237-246 ◽  
Author(s):  
Pankaj ◽  
Shikha Goyal
Keyword(s):  
Electron Microscopy ◽  
Rare Earths ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Amorphous Phases ◽  
Scanning Electron

The ultrasonic decolourisation of two commonly used textile dyes, Acid Red 114 (AR 114) and Reactive Blue 21 (RB 21), with different chromophoric groups, azo and phthalocyanine respectively, has been studied using TiO2 (consisting of mixture of crystalline and amorphous phases) in the presence of rare earths ions (Pr3+, Ce4+). The characterisation of TiO2 has been done through X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, diffuse reflectance spectroscopy (DRS) and N2 adsorption techniques. The decolourisation of AR 114 was faster than for RB 21 under all the experimental conditions. Almost complete decolourisation of both dyes was achieved in 5 min in the presence of US+TiO2+Ce. Ce4+ was found to be more effective than Pr3+. The decolourisation reaction followed second order kinetics. The effects of initial dye concentration and amount of TiO2 on the decolourisation of dyes have been found to be in the order; US+TiO2+Ce > US+TiO2+Pr > US+Ce > US+Pr > US+TiO2 > TiO2 >US. The decolourisation rate increased with increase in TiO2 amount and decreased with increase in initial dye concentration.

The Facile Hydrothermal Preparation of WO3 and its Photocatalytic Performance under Visible-Light Irradiation

2014 ◽  
Vol 936 ◽  
pp. 347-351 ◽  
Author(s):  
Fen Fen Li ◽  
Hong Tao Gao ◽  
Guang Jun Liu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Photocatalytic Performance ◽  
Uv Light ◽  
Hydrothermal Process ◽  
Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Hydrothermal Preparation ◽  
X Ray ◽  
Scanning Electron

The orthorhombic WO3 nanoplates were fabricated via a hydrothermal process, using HBF4 as the acid source. They were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-vis diffused reflectance spectroscopy (UV-Vis DRS), respectively. The WO3 nanoplates exhibited nice UV-light driven photocatalytic performance in the degradation of Rhodamine B (RhB).

The Growth of Tin Oxide Aerogels: Theoretical Modeling and Experimental Characterizations

2015 ◽  
Vol 1731 ◽  
Author(s):  
Carlo Requião da Cunha ◽  
Fábio Dias da Silva ◽  
Renzo Morales
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Scanning Electron Microscopy ◽  
Tin Oxide ◽  
Oxygen Vacancies ◽  
Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fixed Charges ◽  
Scanning Electron

ABSTRACTTin oxide aerogels were synthesized using the epoxide-assisted technique and characterized with X-ray diffraction, diffusive reflectance spectroscopy, particle-induced X-ray emission and scanning electron microscopy. Our results indicate that the material is electrically semi-insulating as the result of oxygen vacancies that appear as fixed charges at the bottom of the conduction band. A modification of the technique with the addition of hydrogen peroxide is proposed to reduce the levels of defects and enhance the optical transparency of the material.

Synthesis of Eu-Doped Bi2O3/CeO2 Composite with Enhanced Photocatalytic Activity by a Facile Sol–Gel–Calcination Route

2015 ◽  
Vol 68 (10) ◽  
pp. 1562 ◽  
Author(s):  
Fengjun Zhang ◽  
Guosheng Xiao ◽  
Wei Lu ◽  
Tianye Wang ◽  
Limin Xuan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uv Visible ◽  
Scanning Electron

Eu-Doped Bi2O3/CeO2 composites were successfully synthesized by a facile sol–gel–calcination route. The as-prepared composites were prepared with different molar ratios of Bi/Ce/Eu by the sol–gel route, and then calcined at 500°C for 2 h. The photocatalytic efficiencies of all composites were tested by degradation of methyl orange (MO) under visible light irradiation. The result suggested that the best composite is the one that was prepared with a Bi/Ce/Eu mole ratio of 8 : 8 : 1, and achieved a MO degradation rate of nearly 98.5 % within 2 h of irradiation. The as-prepared composites were characterized by X-ray diffraction, scanning electron microscopy, inductively coupled plasma mass spectrometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV-visible diffuse reflectance spectroscopy, and photoluminescence spectroscopy. The X-ray diffraction and scanning electron microscopy results suggested that Eu doping may have led to some lattice distortion and particle aggregation that enhanced the photocatalytic activity of the photocatalyst. The UV-visible diffuse reflectance spectroscopy and photoluminescence spectroscopy results showed that Eu-doped Bi2O3/CeO2 exhibited higher visible light response properties and enhanced separation of the photogenerated electron–hole pairs, which is the main reason for the higher photocatalytic activity. In general, this study could provide a facile route to synthesize Eu-doped Bi2O3/CeO2 composites with enhanced photocatalytic activity by a sol–gel–calcination route for environmental purification.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

1992 ◽  
Vol 50 (2) ◽  
pp. 1322-1323
Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Calcium Salts ◽  
Cholesterol Gallstones ◽  
X Ray ◽  
Ca Carbonate ◽  
Scanning Electron

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

Photocatalytic activity of TiO2 synthesized by anodization and anodic spark deposition

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3141-3152
Author(s):  
Alma C. Chávez-Mejía ◽  
Génesis Villegas-Suárez ◽  
Paloma I. Zaragoza-Sánchez ◽  
Rafael Magaña-López ◽  
Julio C. Morales-Mejía ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Surface Characteristics ◽  
Amorphous Solids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Anodic Spark Oxidation ◽  
Porous Surfaces ◽  
Scanning Electron

AbstractSeveral photocatalysts, based on titanium dioxide, were synthesized by spark anodization techniques and anodic spark oxidation. Photocatalytic activity was determined by methylene blue oxidation and the catalytic activities of the catalysts were evaluated after 70 hours of reaction. Scanning Electron Microscopy and X Ray Diffraction analysis were used to characterize the catalysts. The photocatalyst prepared with a solution of sulfuric acid and 100 V presented the best performance in terms of oxidation of the dye (62%). The electric potential during the synthesis (10 V, low potential; 100 V, high potential) affected the surface characteristics: under low potential, catalyst presented smooth and homogeneous surfaces with spots (high TiO2 concentration) of amorphous solids; under low potential, catalyst presented porous surfaces with crystalline solids homogeneously distributed.

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