scholarly journals ACTIVATION ANALYSIS OF HISTORICAL SAMPLES AND NEUTRON SPECTRUM DETERMINATION AT VR-1 TRAINING REACTOR

2016 ◽  
Vol 4 ◽  
pp. 102
Author(s):  
Jan Šturma ◽  
Milan Štefánik
Keyword(s):  
Activation Analysis ◽  
Neutron Spectrum ◽  
Nuclear Reactors ◽  
Relative Method ◽  
Irradiation Channel ◽  
Copper Gold ◽  
Mass Fractions ◽  
The 19Th Century ◽  
Historical Samples

Vertical irradiation channel of the VR-1 training reactor of the Department of Nuclear Reactors CTU was used for activation analysis of historical samples from the 14th to the 19th century. For determination of mass fractions of materials such as copper, gold and silver in irradiated samples, the relative method of activation analysis was used. Further, a set of 24 activation detectors of 12 various materials served for the determination of neutron spectrum of the VR-1 reactor using analytical method; moreover the analytical solution was compared to unfolded spectrum obtained from SAND-II deconvolution program.

Determination of Hydrogen in Semiconductors and Related Materials by Cold Neutron Prompt Gamma-ray Activation Analysis

2004 ◽  
Vol 813 ◽  
Author(s):  
Rick L. Paul
Keyword(s):  
Activation Analysis ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Prompt Gamma ◽  
Porous Thin Films ◽  
Atomic Nuclei ◽  
High Purity Germanium ◽  
Mass Fractions ◽  
Hydrogen Mass

ABSTRACTAn instrument for prompt gamma-ray activation analysis (PGAA) at the NIST Center for Neutron Research has proven useful for the measurement of hydrogen and other elements in a variety of materials. The sample is irradiated by a beam of low energy neutrons. Gamma-rays emitted by atomic nuclei upon neutron capture are measured and elemental concentrations determined by comparison with appropriate standards. The detection limit for hydrogen is < 5 mg/kg in most materials, and 2 mg/kg for hydrogen measured in silicon. The instrument has been used to measure hydrogen mass fractions of < 100 mg/kg in high purity germanium, and < 10 mg/kg in quartz. More recently PGAA has been used to measure hydrogen in 1 μm thick porous thin films on a silicon substrate, and in crystals of silicon carbide and cerium aluminate.

scholarly journals Analysis of Aristolochia Longa L. Medicinal Plant from Algeria

2021 ◽  
Author(s):  
Zohra Lamari ◽  
Houria Negache
Keyword(s):  
Neutron Activation Analysis ◽  
Activation Analysis ◽  
Medicinal Plant ◽  
Recent Time ◽  
Z Score ◽  
The World ◽  
Mass Fractions ◽  
Five Elements ◽  
Certified Values

In recent time, the therapeutic use of medicinal plants has increased all over the world. The efficacy of herbs for curative purposes is often accounted of its mineral and organic constituents. Neutron activation analysis (INAA) has been applied to mineral determination of Aristolochia Longa (bereztem), medicinal plant used to cure some diseases observed in Algeria especially cancer. In this work the mass fractions of Cr (15.22 ± 3.5 μg/g), Na (269.98 ± 25.01 μg/g), La (0.478 ± 0.041 μg/g), K (1.33 ± 0.23 μg/g), Br (1.2 ± 0.19 μg/g), As (0.697 ± 0.038) and Sb (66.09 ± 11.24 μg/g), were determined. This herb was collected from Taourirt Aden Berber village situated in Northern Algeria. Five elements were quantified in certified AIEA standards IAEA-V10 and IAEA-SL1 for checking the accuracy of our procedure. It was noteworthy the values obtained from this work are in good agreement with the certified values, the Z-score values for all elements were |Z| < 3. We believe that herb is natural and harmless compared with chemical drugs. Unfortunately the potential toxicity due to the Aristolochia Acids content has required the analysis of Aristolochia Longa by CG/MS and HPLC to highlight this compound. The standard of Aristolochic Acid (Sigma A5512-25 mg Yellow powder lot # wxbb6331VPCODE) was used as reference.

scholarly journals Significance of the particle physical properties and the Geldart group in the use of correlations for the prediction of minimum fluidization velocity of biomass–sand binary mixtures

2021 ◽  
Author(s):  
Louis Edwards Cáceres-Martínez ◽  
Diana Carolina Guío-Pérez ◽  
Sonia Lucía Rincón-Prat
Keyword(s):  
Physical Properties ◽  
Binary Mixtures ◽  
Minimum Fluidization Velocity ◽  
Fluidization Velocity ◽  
Minimum Fluidization ◽  
Mass Fractions ◽  
Char Particle ◽  
Geldart Groups ◽  
Biomass Particles

AbstractThe present study explores the relevance of the physical properties of biomass particles on the determination of the minimum fluidization velocity (Umf) of binary mixtures. Fluidization experiments were performed in a cold flow unit with diverse biomasses mixed with sand in different mass fractions. Gas velocity and pressure drop across the bed were used to determine Umf. Different correlations reported in the literature were evaluated on their ability to accurately predict Umf of the mixtures. Results showed satisfactory predictions when appropriately identifying correlations according to the corresponding Geldart groups for the biomass particles. This perspective opens new possibilities toward the generalization of correlation factors and helps in improving the accuracy of the prediction for highly heterogeneous mixtures. The methodology also allows the analysis of mixtures for which the experimental approach is difficult, such as those including char particle, with the only requirement of carefully measuring the physical properties of the particles.

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