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In 1979 Philip W. Kuchel published a paper  in the Mathematical Gazette on using curved mirrors as a means of demonstrating the transformation known as inversion in a circle. He called the mirrors ‘anamorphoscopes’ since he came to the idea as a special case of the conical mirror anamorphosis which was a popular optical toy from the seventeenth century onwards . In this paper we revisit his ideas with current technology and provide some extensions to Kuchel's derivation.
We study fluctuations in the drag force resisting the motion of an object being pulled through a dense spherical granular medium. These fluctuations are stick-slip in nature due to the jamming and reorganization of the grains. The fluctuations in the force are periodic at small depths, but they become “stepped” at large depths. We interpret this transition as a consequence of the long-range nature of the force chains.
Advancements in nanotechnology for material processing have spurred the development of superalloys that provide improved protection against corrosion and wear. Nano-scale reactant particles offer unique thermal properties and increased homogeneity that may improve the microstructural features and macroscopic properties of the final product. In this study up to 10-wt% nano-scale molybdenum tri-oxide (MoO3) particles were added to micron scale nickel (Ni) and aluminum (Al). The goal was to produce a superalloy by generating excessively high heating rates and adding an oxidizer that would produce small quantities of Al2O3 (a strengthening agent) within the microstructure of the alloy. Experiments were performed on pellets pressed to 60% theoretical maximum density. Ignition and flame propagation were examined using a CO2 laser and imaging diagnostics that include a copper-vapor laser coupled with a high-speed camera. Product microstructure was examined using scanning electron microscopy. Abrasion testing was performed to evaluate the wear resistance properties of the superalloy. Results show that adding MoO3 increases the flame temperature and produces greater ignition sensitivity. Also, small quantities of MoO3 produce a more homogeneous microstructure and increase the overall wear resistance of the product.
Advancements in nanotechnology for material processing via combustion synthesis have spurred the development of superalloys that provide improved protective properties. Nanoscale reactant particles offer unique thermal properties and increased homogeneity that improve the microstructural features and macroscopic properties of the synthesized product. In this study nanoscale molybdenum trioxide (MoO3) particles were added to micron scale nickel (Ni) and aluminum (Al). The goal was to incorporate a nanoscale additive within the reactant matrix that would produce a superalloy by generating excessively high heating rates and creating controlled quantities of Al2O3 (a strengthening agent) within the microstructure of the alloy. Ignition and flame propagation were examined using a CO2 laser and imaging diagnostics that include a copper-vapor laser coupled with a high-speed camera. Product microstructure was examined using micro-x-ray diffraction analysis and scanning electron microscopy. Abrasion testing was performed to evaluate the wear resistance properties of the superalloy. Results show that adding MoO3 increases the flame temperature, results in greater ignition sensitivity, produces a more homogeneous microstructure, and increases the overall wear resistance of the product.
The mechanism by which the type Iα regulatory
subunit (RIα) of cAMP-dependent protein kinase is localized
to cell membranes is unknown. To determine if structural
modification of RIα is important for membrane association,
both beef skeletal muscle cytosolic RI and beef heart membrane-associated
RI were characterized by electrospray ionization mass spectrometry.
Total sequence coverage was 98% for both the membrane-associated
and cytosolic forms of RI after digestion with AspN protease
or trypsin. Sequence data indicated that membrane-associated
and cytosolic forms of RI were the same RIα gene product.
A single RIα phosphorylation site was identified at
Ser81 located near the autoinhibitory domain of both membrane-associated
and cytosolic RIα. Because both R subunit preparations
were 30–40% phosphorylated, this post-translational
modification could not be responsible for the membrane
compartmentation of the majority of RIα. Mass spectrometry
also indicated that membrane-associated RIα had a higher
extent of disulfide bond formation in the amino-terminal
dimerization domain. No other structural differences between
cytosolic and membrane-associated RIα were detected.
Consistent with these data, masses of the intact proteins
were identical by LCQ mass spectrometry. Lack of detectable
structural differences between membrane-associated and
cytosolic RIα strongly suggests an interaction between
RIα and anchoring proteins or membrane lipids as more
likely mechanisms for explaining RIα membrane association
in the heart.
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