Non-Abelian Einstein-Born-Infeld Black Holes

We construct regular and black hole solutions in SU(2) Einstein-Born-Infeld theory. These solutions have many features in common with the corresponding SU(2) Einstein-Yang-Mills solutions. In particular, sequences of neutral non-abelian solutions tend to magnetically charged limiting solutions, related to embedded abelian solutions. Thermodynamic properties of the black hole solutions are addressed.Comment: LaTeX, 14 pages, 6 postscript figures; typos corrected in reference

Inflation with a constant ratio of scalar and tensor perturbation amplitudes

The single scalar field inflationary models that lead to scalar and tensor perturbation spectra with amplitudes varying in direct proportion to one another are reconstructed by solving the Stewart-Lyth inverse problem to next-to-leading order in the slow-roll approximation. The potentials asymptote at high energies to an exponential form, corresponding to power law inflation, but diverge from this model at low energies, indicating that power law inflation is a repellor in this case. This feature implies that a fine-tuning of initial conditions is required if such models are to reproduce the observations. The required initial conditions might be set through the eternal inflation mechanism. If this is the case, it will imply that the spectral indices must be nearly constant, making the underlying model observationally indistinguishable from power law inflation.Comment: 20 pages, 7 figures. Major changes to the Introduction following referee's comments. One figure added. Some other minor changes. No conclusion was modifie

The Energy of Regular Black Hole in General Relativity Coupled to Nonlinear Electrodynamics

According to the Einstein, Weinberg, and M{\o}ller energy-momentum complexes, we evaluate the energy distribution of the singularity-free solution of the Einstein field equations coupled to a suitable nonlinear electrodynamics suggested by Ay\'{o}n-Beato and Garc\'{i}a. The results show that the energy associated with the definitions of Einstein and Weinberg are the same, but M{\o}ller not. Using the power series expansion, we find out that the first two terms in the expression are the same as the energy distributions of the Reissner-Nordstr\"{o}m solution, and the third term could be used to survey the factualness between numerous solutions of the Einstein field eqautions coupled to a nonlinear electrodynamics.Comment: 11 page

Residual stress and fracture in thick tetraethylorthosilicate (TEOS) and silane-based PECVD oxide films

This paper reports residual stress measurements and fracture analysis in thick tetraethylorthosilicate (TEOS) and silane-based plasma enhanced chemical vapor deposition (PECVD) oxide films. The measured residual stress depended strongly on thermal process parameters; dissolved hydrogen gases played an important role in governing intrinsic stress. The tendency to form cracks was found to be a strong function of film thickness and annealing temperature. Critical cracking temperature was predicted using mixed mode fracture mechanics, and the predictions provide a reasonable match to experimental observations. Finally, engineering solutions were demonstrated to overcome the problems caused by wafer bow and film cracks. The results of this study should be able to provide important insights for the design of fabrication processes for MEMS devices requiring high temperature processing of films

Multi-stack silicon-direct wafer bonding for 3D MEMS manufacturing

Multi-stack wafer bonding is one of the most promising fabrication techniques for creating three-dimensional (3D) microstructures. However, there are several bonding issues that have to be faced and overcome to build multilayered structures successfully. Among these are: (1) chemical residues on surfaces to be bonded originating from the fabrication processes prior to bonding; (2) increased stiffness due to multiple bonded wafers and/or thick wafers; (3) bonding tool effects; (4) defect propagation to other wafer-levels after high-temperature annealing cycles. The problems and the solutions presented here are readily applicable to any microelectromechanical systems project involving the fabrication of multi-stack structures of two or more wafers containing intricate geometries and large etched areas

Microfabrication of a high pressure bipropellant rocket engine

A high pressure bipropellant rocket engine has been successfully micromanufactured by fusion bonding a stack of six individually etched single crystal silicon wafers. In order to test the device, an innovative packaging technique was developed to deliver liquid coolant and gaseous propellants to the rocket chip at pressures in excess of 200 atm at temperatures above 300°C. Testing continues on the 1.2 g devices, which have been run to date at a chamber pressure of 12 atm, generating 1 N of thrust, and delivering a thrust power of 750 W