Studies of low frequency RF systems for muon cooling has led to a variety of new techniques for looking at dark currents, a new model of breakdown, and, ultimately, a model of RF cavity operation based on surface damage. We find that cavity behavior is strongly influenced by the spectrum of enhancement factors on field emission sites. Three different spectra are involved: one defining the initi...

The obtained Q0 value of a superconducting niobium cavity is known to depend on various factors like the RRR of the Niobium material, crystallinity, chemical treatment history, the high-pressure rinsing process, or effectiveness of the magnetic shielding. We have observed that spatial thermal gradients over the cavity length during cool-down appear to contribute to a degradation of Q0. Measurem...

Discontinuous velocity boundary data for the lid driven cavity flow has long been causing difficulties in both theoretical analysis and numerical simulations. In finite element methods, the variational form for the driven cavity flow is not valid since the velocity is not in H. Hence standard error estimates do not work. By using only W1,r (1 < r < 2) regularity and constructing a continuous ap...

We describe a cryogenic cavity-optomechanical system that combines Si3N4 membranes with a mechanically rigid Fabry–Perot cavity. The extremely high products of quality factor and frequency of the membranes allow us to cool a MHz mechanical mode to a phonon occupation of n̄ < 10, starting at a bath temperature of 5K. We show that even at cold temperatures thermally occupied mechanical modes of th...

This paper presents a kind of passive wireless pressure sensor comprised of a planar spiral inductor and a cavity parallel plate capacitor fabricated through low-temperature co-fired ceramic (LTCC) technology. The LTCC material with a low Young's modulus of ~65 GPa prepared by our laboratory was used to obtain high sensitivity. A three-step lamination process was applied to construct a high qua...

A model of a supersonic free-vortex aerodynamic window has been fabricated and tested. Aerodynamic performance studies show the effectiveness of the model in sealing the simulated laser cavity from higher pressure ambient surroundings. Good starting characteristics and stability of the supersonic window jet are obtained. Static pressure measurements and photographs of the flow fields clearly sh...

The interaction between fine grains and the surrounding interstitial gas in a granular bed can lead to qualitatively new phenomena not captured in a simple, single-fluid model of granular flows. This is demonstrated by the granular jet formed by the impact of a solid sphere into a bed of loose, fine sand. Unlike jets formed by impact in fluids, this jet is actually composed of two separate comp...

We report on experimental observation of radiation-pressure induced effects in a high-power optical cavity. These effects play an important role in next generation gravitational wave (GW) detectors, as well as in quantum non-demolition (QND) interferometers. We measure the properties of an optical spring, created by coupling of an intense laser field to the pendulum mode of a suspended mirror; ...

Fundoplication (FP) efficacy is a trade-off between protection against reflux and postoperative dysphagia from the surgically altered mechanical balance within the esophagogastric segment. The purpose of the study was to contrast quantitatively the mechanical balance between normal and post-FP esophageal emptying. Physiological data were combined with mathematical models based on the laws of me...

The research conducted in the paper highlights importance of pressure or holding mold cavity as a critical production parameter high-pressure die casting process for Al-Si alloys. experiments revealed direct correlation between and mechanical properties castings, including ultimate tensile strength, percentage share porosity, structure results showed that increasing led to an increase strength ...