Recently there is an increasing need
for experiments that can be
conducted remotely. In this sense, this paper presents three experiments
about materials science and an X-ray diffraction (XRD) technique that
can be taught and performed entirely remotely. The first experiment
is about the calculation of lattice parameters, atomic radii, and
densities of metallic elements with a body-centered cubic (BCC) structure.
The second experiment is about the calculation of lattice parameters,
axial ratios, unit cell volumes, and densities of yttria-stabilized
zirconia (YSZ) solid solutions. The third experiment is about applying
the Rietveld refinement technique to distinguish the enantiomers of
the pharmaceutical molecule naproxen and determine the hydration degree
of commercial naproxen sodium pills. For the first two experiments,
students worked with simulated data, whereas for the third one, they
worked with experimental data collected and provided by the Instructor.
Besides the materials science and XRD concepts, students were introduced
to the operation of the free softwares Vesta and GSAS II and to the
Crystallography Open Database, a free database for structural data
of organic and inorganic compounds. The paper explains the background,
goals, and results obtained by the students in each one of the experiments.
Detailed information about the experimental procedures and their implementation
is complemented by the Supporting Information file and Supporting
Videos. Although the experiments were presented in an increasing level
of difficulty, they are independent of each other, allowing the instructors
to apply them according to their needs and learning objectives.
Photocatalytic membrane reactor (PMR) is a promising treatment technology for degradation of the organic compounds discharged from wastewater treatment facilities. This review presents information about the TiO2 nanoparticles, which is...
The properties of ideal tri-functional dendrimers with forty-five, ninety-three and one hundred and eighty-nine branches are investigated. Three methods are employed to calculate the mean-square radius of gyration, g-ratios, asphericity, shape parameters and form factor. These methods include a Kirchhoff matrix eigenvalue technique, the graph theory approach of Benhamou et al. (2004), and Monte Carlo simulations using a growth algorithm. A novel technique for counting paths in the graph representation of the dendrimers is presented. All the methods are in excellent agreement with each other and with available theoretical predictions. Dendrimers become more symmetrical as the generation and the number of branches increase.
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