scholarly journals Measurement of Diffusion in Liquids within Porous Solids by X-Ray Microradiography: Determination of Errors and Optimization of Experimental Conditions

1995 ◽  
Vol 6 (2) ◽  
pp. 187-203 ◽  
Author(s):  
Stephanie E. P. Dowker ◽  
Paul Anderson ◽  
James C. Elliott
Keyword(s):  
Porous Solids ◽  
Experimental Conditions ◽  
X Ray ◽  
Diffusion In Liquids ◽  
Optimization Of Experimental Conditions

POSITRON FACILITIES TESTS OF THE X-RAYS PRODUCED BY CRYSTALLINE UNDULATORS

2005 ◽  
Vol 19 (03) ◽  
pp. 85-98 ◽  
Author(s):  
S. BELLUCCI
Keyword(s):  
Positron Beam ◽  
Precise Determination ◽  
X Rays ◽  
Experimental Conditions ◽  
X Ray ◽  
Accelerated Particles

One of the main involvements of the INFN-Laboratori Nazionali di Frascati group in channeling researches is described, i.e. the crystal undulator R & D, with the characterization of the crystal undulator prototypes with SEM and the positron beam. We consider a precise determination of the optimal experimental conditions for channeling of this kind of accelerated particles through such microstructured crystals, as promising candidates for producing X-ray beams.

Preparation of A Magnetic Nanosensor Based on Cobalt Ferrite Nanoparticles for The Electrochemical Determination of Methyldopa in The Presence of Uric Acid

2020 ◽  
Vol 23 (10) ◽  
pp. 1023-1031
Author(s):  
Khadijeh Najafi ◽  
Karim Asadpour-Zeynali ◽  
Fariba Mollarasouli
Keyword(s):  
Uric Acid ◽  
Electrochemical Sensor ◽  
Cobalt Ferrite ◽  
Electrochemical Determination ◽  
Ferrite Nanoparticles ◽  
Current Response ◽  
Experimental Conditions ◽  
X Ray ◽  
Cobalt Ferrite Nanoparticles

Aim and Objective: Methyldopa is one of the medications that is used for the treatment of hypertension. Therefore, the determination of methyldopa in the presence of other biological components is essential. In this work, a promising electrochemical sensor based on CoFe2O4 magnetic nanoparticles modified glassy carbon electrode (CoFe2O4/GCE) was developed for electrochemical determination of methyldopa in the presence of uric acid. Cobalt ferrite nanoparticles were synthesized via chemical method. Materials and Methods: Characterizing the CoFe2O4 was investigated by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), transmission electron microscope (TEM), and cyclic voltammetry techniques. Results: Under the optimal experimental conditions, the current response of the electrochemical sensor obtained with differential pulse voltammetry was increased linearly in the concentration range from 1.45 to 15.1 μmol L−1 with the detection limit of 1.07 μmol L−1 for methyldopa. Also, by using the proposed method, methyldopa and uric acid could be analyzed in a mixture independently. The difference in peak potential for analytes is about 150 mV. Conclusion: The present sensor was successfully applied for the determination of methyldopa in the presence of uric acid in biological samples and the pharmaceutical samples with satisfactory results.

Derivation of d-Values from Digitized X-ray and Synchrotron Diffraction Data

1989 ◽  
Vol 33 ◽  
pp. 295-303 ◽  
Author(s):  
T. C. Huang ◽  
W. Parrish ◽  
N. Masciocchi ◽  
P. W. Wang
Keyword(s):  
Diffraction Data ◽  
Practical Method ◽  
Xrd Analysis ◽  
Lattice Parameter ◽  
Lattice Parameters ◽  
Synchrotron Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
D Values

AbstractA precise and practical method for the determination of d-values and lattice parameters from digital diffraction data is described. Systematic errors are corrected mathematically during a d-spacing / lattice-parameter least-Squares refincment process making it unnecessary to use internal standards. X-ray and synchrotron diffraction data of an ICDD alumina plate obtained with a wide variety of experimental conditions and analysis parameters were used to study the precision in the derivation of d-values and the accuracy in the determination of lattice parameters. Results showed that the precision in determining d-values was high with |Δd/d|avg ranging from 2x105 to 4x10-5. Using the results obtained from the high precision XRD analysis as a reference standard, the accuracy in the lattice parameter determinations from the synchrotron diffraction data reached the l-2x10-6] range. Lattice parameters, with an accuracy in the high 10-5 range, were also obtained using parameters commonly used in a routine XRD analysis such as a wide RS (0.11°) for high intensity, peaks only in the front reflection region, no Kα2 stripping, and a Single 2θo parameter for systematic error corrections.

Determination of Structure, Shape and Sizes of Clusters Using Radial Distribution Functions (RDF) Method

1992 ◽  
Vol 272 ◽  
Author(s):  
Pavel E. Kolosov ◽  
A. V. Bubnov
Keyword(s):  
Distribution Functions ◽  
Structure Characterization ◽  
Radial Distribution Functions ◽  
Experimental Conditions ◽  
Interatomic Distances ◽  
X Ray ◽  
Molybdenum Sulfides ◽  
X Ray Scattering

ABSTRACTThe theoretical reduced intensity of X-ray scattering i(S) may be calculated for a cluster of any structure using Debye's formula. The comparison of both experimental determination and model calculation of the RDF or i(S) allows, to make a conclusions about structure of materials in a wide region of interatomic distances. This is a very important for direct structure characterization of giant clusters, dispersed molybdenum sulfides etc.. The simple formula for the upper limit of interatomic distances when the data are collected at equidistant step on S – scatterinrg vector, may be used for the optimal experimental conditions selection.

scholarly journals Investigation of zinc stannate synthesis using photoacoustic spectroscopy

2007 ◽  
Vol 39 (2) ◽  
pp. 153-160 ◽  
Author(s):  
T. Ivetic ◽  
M.V. Nikolic ◽  
P.M. Nikolic ◽  
V. Blagojevic ◽  
S. Djuric ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Ball Mill ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Microstructure Characteristics ◽  
Amplitude Spectra ◽  
Scanning Electron

Mixtures of ZnO and SnO2 powders, with molar ratio of 2:1, were mechanically activated for 40, 80 and 160 minutes in a planetary ball mill. The resulting powders were compacted into pellets and non-isothermally sintered up to 1200?C with a heating rate of 5?C/min. X-ray diffraction analysis of obtained powders and sintered samples was performed in order to investigate changes of the phase composition. The microstructure of sintered samples was examined by scanning electron microscopy. The photoacoustic phase and amplitude spectra of sintered samples were measured as a function of the laser beam modulating frequency using a transmission detection configuration. Fitting of experimental data enabled determination of photoacoustic properties including thermal diffusivity. Based on the results obtained a correlation between thermal diffusivity and experimental conditions as well the samples microstructure characteristics was discussed. .

Determination Of The Content Of Hf In Zirconium Alloys With Using A Wide Band X-Ray Emission Filter

2018 ◽  
pp. 153-159
Author(s):  
O.P. Omelnyk ◽  
V.V. Levenets ◽  
A.Yu. Lonin ◽  
I.V. Shevchenko ◽  
A.O. Shchur
Keyword(s):  
Pyrolytic Graphite ◽  
Zirconium Alloys ◽  
Analytical Signal ◽  
Wide Band ◽  
Optimal Conditions ◽  
Experimental Conditions ◽  
X Ray ◽  
Method Of Determination ◽  
Non Destructive

The possibilities of a non-destructive method of determination of the content of hafnium in zirconium alloys are studied. The method is based on excitation of the characteristic X-ray emission of the atoms of the object of interest, including the L-series of atom of Hf, by external beam of protons accelerated up to 2 MeV. The excited emission is modified by a wide band X-ray emission filter, which is made from pyrolytic graphite plates and measured by a Si-PIN detector. Optimal conditions for measurement of analytical signal were determined after experimental studying. It was shown that under the selected experimental conditions and the measurement time of 10 minutes, the detection limit of Hf in the zirconium matrix is equal 20 ppm. The ways for improving of the metrological characteristics of the technique in the presence of interfering elements are proposed. The content of hafnium and uniformity of its distribution in the cladding of nuclear fuel rod made from the alloy Zr1% Nb was determined.

scholarly journals Synthesis of barium-zinc-titanate ceramics

2012 ◽  
Vol 44 (1) ◽  
pp. 65-71 ◽  
Author(s):  
N. Obradovic ◽  
M.V. Nikolic ◽  
N. Nikolic ◽  
S. Filipovic ◽  
M. Mitric ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Zinc Titanate ◽  
X Ray ◽  
Microstructure Characteristics ◽  
Amplitude Spectra ◽  
Titanate Ceramics

Mixtures of BaCO3, ZnO and TiO2 powders, with molar ratio of 1:2:4, were mechanically activated for 20, 40 and minutes in a planetary ball mill. The resulting powders were compacted into pellets and isothermally sintered at 1250?C for 2h with a heating rate of 10?C/min. X-ray diffraction analysis of obtained powders and sintered samples was performed in order to investigate changes of the phase composition. The microstructure of sintered samples was examined by scanning electron microscopy. The photoacoustic phase and amplitude spectra of sintered samples were measured as a function of the laser beam modulating frequency using a transmission detection configuration. Fitting of experimental data enabled determination of photoacoustic properties including thermal diffusivity. Based on the results obtained correlation between thermal diffusivity and experimental conditions, as well the samples microstructure characteristics, was discussed.

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