O-ring gasket test fixture

An apparatus is presented for testing O-ring gaskets under a variety of temperature, pressure, and dynamic loading conditions. Specifically, this apparatus has the ability to simulate a dynamic loading condition where the sealing surface in contact with the O-ring moves both away from and axially along the face of the O-ring

Ring for test of nonlinear integrable optics

Nonlinear optics is a promising idea potentially opening the path towards achieving super high beam intensities in circular accelerators. Creation of a tune spread reaching 50% of the betatron tune would provide strong Landau damping and make the beam immune to instabilities. Recent theoretical work has identified a possible way to implement stable nonlinear optics by incorporating nonlinear focusing elements into a specially designed machine lattice. In this report we propose the design of a test accelerator for a proof-of-principle experiment. We discuss possible studies at the machine, requirements on the optics stability and sensitivity to imperfections.Comment: 3 pp. Particle Accelerator, 24th Conference (PAC'11) 28 Mar - 1 Apr 2011: New York, US

On utilization of elliptical rings in assessing cracking tendency of concrete

A new experimental method by utilizing elliptical rings to replace circular rings recommended by ASTM and AASHTO was explored for assessing cracking potential of concrete and other cement-based materials under restrained condition. A series of thin and thick elliptical concrete rings were tested alongside circular ones until cracking. Cracking age, position, and propagation were carefully examined. It is found that thin elliptical rings with appropriate geometry can initiate cracks quicker than circular ones, which is desirable for accelerating the ring test. However, thick elliptical rings seem not to exhibit a desirable geometry effect of accelerating ring test compared with circular ones. There were multiple visible cracks that occurred in an elliptical ring and some cracks were initiated but did not propagate through the ring wall. In comparison, there was only one crack in the circular rings. Finally, the features of multiple cracks in restrained elliptical rings were examined and their impact on interpreting elliptical ring test results was elaborated. © 2014 4th International Conference on the Durability of Concrete Structures

Geodesics around Weyl-Bach's Ring Solution

We explore some of the gravitational features of a uniform ring both in the Newtonian potential theory and in General Relativity. We use a spacetime associated to a Weyl static solution of the vacuum Einstein's equations with ring like singularity. The Newtonian motion for a test particle in the gravitational field of the ring is studied and compared with the corresponding geodesic motion in the given spacetime. We have found a relativistic peculiar attraction: free falling particle geodesics are lead to the inner rim but never hit the ring.Comment: 8 figures, 14 pages. LaTeX w/ subfigure, graphic

The ring compression test: Analysis of dimensions and canonical geometry

The compression ring test is universally accepted as a perfectly valid method by which determine simply and reliably the adhesion friction factor in a plastic deformation process. Its methodology is based on the application of geometric changes as both the reduction in thickness as the decrease in bore inner diameter in the strained ring itself. In this paper the performance of that test is the basis for establishing the coefficient of friction on a forging process so that, given this, its application to Upper Bound Theorem (UBT) by model Triangular Rigid Zones (TRZ), enable the establishment an intercomparison with empirical force, reaching a cuasivalidation of this Theorem in a certain range.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Gravitomagnetic Field of Rotating Rings

In the framework of the so-called gravitoelectromagnetic formalism, according to which the equations of the gravitational field can be written in analogy with classical electromagnetism, we study the gravitomagnetic field of a rotating ring, orbiting around a central body. We calculate the gravitomagnetic component of the field, both in the intermediate zone between the ring and the central body, and far away from the ring and central body. We evaluate the impact of the gravitomagnetic field on the motion of test particles and, as an application, we study the possibility of using these results, together with the Solar System ephemeris, to infer information on the spin of ring-like structures.Comment: 8 pages, 2 figures; revised to match the version accepted for publication in Astrophysics and Space Scienc

Study of the Mechanical Strength Improvement of Wafers for EWT Solar Cells by Chemical Etching after the Drilling Process

Mechanical stability of EWT solar cells deteriorates when holes are created in the wafer. Nevertheless, the chemical etching after the hole generation process improves the mechanical strength by removing part of the damage produced in the drilling process. Several sets of wafers with alkaline baths of different duration have been prepared. The mechanical strength has been measured by the ring on ring bending test and the failure stresses have been obtained through a FE simulation of the test. This paper shows the comparison of these groups of wafers in order to obtain an optimum value of the decreased thickness produced by the chemical etchin

Fluctuations for analytic test functions in the Single Ring Theorem

We consider a non-Hermitian random matrix $A$ whose distribution is invariant under the left and right actions of the unitary group. The so-called Single Ring Theorem, proved by Guionnet, Krishnapur and Zeitouni, states that the empirical eigenvalue distribution of $A$ converges to a limit measure supported by a ring $S$. In this text, we establish the convergence in distribution of random variables of the type $Tr (f(A)M)$ where $f$ is analytic on $S$ and the Frobenius norm of $M$ has order $\sqrt{N}$. As corollaries, we obtain central limit theorems for linear spectral statistics of $A$ (for analytic test functions) and for finite rank projections of $f(A)$ (like matrix entries). As an application, we locate outliers in multiplicative perturbations of $A$.Comment: 29 pages, 1 figure. In Version v2, we slightly modified the assumptions, in order to fix a problem un the control of the tails (see Assumption 2.3). In v3, some minors typos were corrected. In v4, some explanations were added in the introduction and some typos were corrected. To appear in Indiana Univ. Math.

Experimental evaluation of the ring focus test for X-ray telescopes using AXAF's technology mirror assembly, MSFC CDDF Project No. H20

A test method particularly suited for X-ray telescopes was evaluated experimentally. The method makes use of a focused ring formed by an annular aperture when using a point source at a finite distance. This would supplement measurements of the best focus image which is blurred when the test source is at a finite distance. The telescope used was the Technology Mirror Assembly of the Advanced X-ray Astrophysis Facility (AXAF) program. Observed ring image defects could be related to the azimuthal location of their sources in the telescope even though in this case the predicted sharp ring was obscured by scattering, finite source size, and residual figure errors