Linear-acoustic effects of asymmetrical undercutting of toneholes of woodwind instruments.

The influence of the presence and magnitude of asymmetrical undercutting of the toneholes of woodwind instruments on the change in their effective radius and the corresponding shift of the eigenfrequencies of the air duct is considered. Within the framework of the electro-acoustic analogy, a tonehole with an asymmetrical undercutting along the axis of the main bore is presented as a cascade connection of two holes with different radii (undercutting and not undercutting parts of the hole), and with a sideway undercutting-in the form of a parallel connection. Formulas for numerical calculations are given that make it possible to determine the effective radius of such holes for the open state in the low-frequency approximation.

Nafion: New and Old Insights into Structure and Function.

The work reports a number of results on the dynamics of swelling and inferred nanostructure of the ion-exchange polymer membrane Nafion in different aqueous solutions. The techniques used were photoluminescent and Fourier transform IR (FTIR) spectroscopy. The centers of photoluminescence were identified as the sulfonic groups localized at the ends of the perfluorovinyl ether (Teflon) groups that form the backbone of Nafion.

Inelastic Deformation of Coronary Stents: Two-Level Model.

This study describes the internal structure of materials used to produce medical stents. A two-level elastoviscoplastic mathematical model, which sets the parameters and describes the processes at the grain level, was developed and numerically implemented. A separate study was conducted to identify the most dangerous deformation modes in the balloon-expandable stent placement using the finite-element method in COMSOL Multiphysics.

Measurement of the two-photon exchange contribution to the elastic e(±)p scattering cross sections at the VEPP-3 storage ring.

The ratio of the elastic e(+)p to e(-)p scattering cross sections has been measured precisely, allowing the determination of the two-photon exchange contribution to these processes. This neglected contribution is believed to be the cause of the discrepancy between the Rosenbluth and polarization transfer methods of measuring the proton electromagnetic form factors. The experiment was performed at the VEPP-3 storage ring at beam energies of 1.

[Telemetric shock-wave lithotripsy on a new Russia LGK-Kompakt 9701U lithotriptor].

During clinical tests of a new Russian [symbol: see text]K-Kom[symbol: see text]akt 9701[symbol: see text] lithotriptor, the Urological Unit of the Moscow Regional Research and Clinical Institute performed 73 sessions of telemetric shock-wave lithotripsy (TIWL) in 43 patients with urolithiasis (20 females and 23 males whose age ranged from 23 to 78 years). The tests indicated that the new device meets all present medical and engineering requirements for lithotriptors having an ultrasound stone-picking-up system and has some advantages over the analogues made in foreign countries in both medical and engineering indices. The device provides good images of renal calculi and destroys them effectively, of peripelvic and intramural portions of the ureter, and the urinary bladder.