The inner surface of the ring vacuum chambers of the US Spallation Neutron Source (SNS) will be coated with ~100 nm of Titanium Nitride (TiN). This is to minimize the secondary electron yield (SEY) from the chamber wall, and thus avoid the so-called e-p instability caused by electron multipacting as observed in a few high-intensity proton storage rings. Both DC sputtering and DCmagnetron sputte...

This paper presents experimental and numerical results for fully-clamped square steel plates to elucidate how the deformation failure are affected by presence of pre-formed holes, holes’ geometry, under confined blast loading. The geometry holes will be shown play a crucial role in plate. Numerical simulations successfully predict inelastic crack propagation observed experiments; and, it that v...

Micromixers have important applications in various pharmaceutical and medical fields. In the present study, enhancement of mixing index electroosmotic micromixer with different geometries is investigated. The commercial software COMSOL Multiphysics 5.4 employed to solve mathematical models. SIMPLEC
 algorithm for coupling velocity pressure A second-order upwind scheme used reduce artificia...

In this paper we present a radial sample preconcentration strategy enabled by axisymmetric concentration polarization in a microfluidic chamber on a uniform nanoporous film. Sample analytes are focused into the centre, creating a concentrated plug that is injected vertically into the microfluidic analysis layer. No balancing pressure driven flows or tangential fields are required, and the proce...

The overall efficiency of a regenerative chamber for a glass furnace mainly relies on the thermo-fluid dynamics of air and waste gas alternatively flowing through stacks of refractory bricks (checkers) determining the heat recovery. A numerical approach could effectively support the design strategies in order to achieve a deeper understanding of the current technology and hopefully suggest new ...

Dynamic flow losses in the suction chamber are a significant factor in reducing screw compressor efficiency but can only be roughly estimated in compressor design due to the simplified methods of analysis used to account for them. Today, Computational Fluid Mechanics analysis may be used to estimate velocity, pressure, temperature and concentration fields within a screw compressor far more accu...

'3'CS y~ray sources, whic h have been proposed by the Pub lic Health Service as a subs titute for radium in th e treatme nt of ma lignant diseases, require suitab le calibration if cons is tency is to be achie ved in radiation treatme nt. Several '"'Cs so urces we re ca libra ted using a graphite cavi ty ionizat ion chambe r in an open·ai r geometry. The co ntribution of scatter from the room s...

A symplectic polarity of a building ∆ of type E6 is a polarity whose fixed point structure is a building of type F4 containing residues isomorphic to symplectic polar spaces. In this paper, we present two characterizations of such polarities among all dualities. Firstly, we prove that, if a duality θ of ∆ never maps a point to a neighbouring symp, and maps some element to a non-opposite element...

The synthesis of wurtzite gallium nitride (GaN) nanorods with triangular shape on c-Al2O3 substrates using a thermal chemical vapor deposition process was investigated. It was possible to control nanorod shape and growth mode of GaN nanorods by change of sample geometry in the chamber using a mixture of GaN powder and Ga metal with ammonia gas reaction. It was found that the GaN nanorods were g...

Even scientific grade optical glasses show birefringence when small external forces are applied to the sample. Stress-induced birefringence can be particularly detrimental to the state of polarization of light when a laser beam is transmitted through the glass. This is especially the case for glass windows of a vacuum chamber. Since compensation of spatially inhomogeneous birefringence is extre...