3 research outputs found
New Efficient Organic Scintillators Derived from Pyrazoline
We
report on the synthesis, spectroscopic and scintillation properties
of three new pyrazoline core based fluorophores. Fluorescence properties
of the fluorophores have been studied both in a solution state and
in a solid polyvinyltoluene (PVT) resin matrix of different porosity.
The synthesized fluorophores were found to be promising candidates
for application in plastic scintillators for detection of ionizing
radiation (alpha, beta particles, γ rays and neutrons) and demonstrated
superior efficiency in comparison to the existing commercially used
fluorophores (2-(1-naphthyl)-5-phenyloxazole (αNPO), 9,10-diphenylanthracene,
etc.). Moreover, the suggested synthetic route allows functionalization
of the fluorophores with a vinyl group for further covalent bound
to the PVT or other vinyl polymer matrices, which dramatically improves
chemical stability of the system simultaneously improving the photoluminescence
quantum yield. Possible mechanisms of the enhanced scintillation properties
are discussed based on preliminary quantum mechanical calculations
and spectroscopic characteristics of the fluorophores under study
High-Resolution 4D Preclinical Single-Photon Emission Computed Tomography/X-ray Computed Tomography Imaging of Technetium Transport within a Heterogeneous Porous Media
A dynamic <sup>99m</sup>Tc tracer experiment was performed to investigate
the capabilities of combined preclinical single photon emission computed
tomography (SPECT) and X-ray computed tomography (CT) for investigating
transport in a heterogeneous porous medium. The experiment was conducted
by continuously injecting a <sup>99m</sup>Tc solution into a column
packed with eight layers (i.e., soil, silica gel, and 0.2–4
mm glass beads). Within the imaging results it was possible to correlate
observed features with objects as small as 2 mm for the SPECT and
0.2 mm for the CT. Time-lapse SPECT imaging results illustrated both
local and global nonuniform transport phenomena and the high-resolution
CT data were found to be useful for interpreting the cause of variations
in the <sup>99m</sup>Tc concentration associated with structural features
within the materials, such as macropores. The results of this study
demonstrate SPECT/CT as a novel tool for 4D (i.e., transient three-dimensional)
noninvasive imaging of fate and transport processes in porous media.
Despite its small scale, an experiment with such high resolution data
allows us to better understand the pore scale transport which can
then be used to inform larger scale studies
High-Resolution 4D Preclinical Single-Photon Emission Computed Tomography/X-ray Computed Tomography Imaging of Technetium Transport within a Heterogeneous Porous Media
A dynamic <sup>99m</sup>Tc tracer experiment was performed to investigate
the capabilities of combined preclinical single photon emission computed
tomography (SPECT) and X-ray computed tomography (CT) for investigating
transport in a heterogeneous porous medium. The experiment was conducted
by continuously injecting a <sup>99m</sup>Tc solution into a column
packed with eight layers (i.e., soil, silica gel, and 0.2–4
mm glass beads). Within the imaging results it was possible to correlate
observed features with objects as small as 2 mm for the SPECT and
0.2 mm for the CT. Time-lapse SPECT imaging results illustrated both
local and global nonuniform transport phenomena and the high-resolution
CT data were found to be useful for interpreting the cause of variations
in the <sup>99m</sup>Tc concentration associated with structural features
within the materials, such as macropores. The results of this study
demonstrate SPECT/CT as a novel tool for 4D (i.e., transient three-dimensional)
noninvasive imaging of fate and transport processes in porous media.
Despite its small scale, an experiment with such high resolution data
allows us to better understand the pore scale transport which can
then be used to inform larger scale studies