Measurement of the Proton Structure Function F2F_2 and the Extraction of the Gluon Density at Small xx

In the following article we describe our measurement of the proton structure function $F_2$ and of the gluon momentum density $xg$ in $ep$ collisions with the ZEUS detector at HERA in 1993. The results for $F_2$ confirm our measurement from the previous year but with much higher statistics and show a strong rise towards small $x$. The gluon momentum density $xg$ is measured for the first time in a range from $4 \cdot 10^{-4} < x < 10^{-2}$ at a value of $Q^2 = 20$~GeV$^2$.Comment: 7 pages uuencode-gzipped postscript. LaTeX and individual figures can be found on http://ppewww.ph.gla.ac.uk/preprints/95/01/fleck.shtm

Tungsten wire/FeCrAlY matrix turbine blade fabrication study

The objective was to establish a viable FRS monotape technology base to fabricate a complex, advanced turbine blade. All elements of monotape fabrication were addressed. A new process for incorporation of the matrix, including bi-alloy matrices, was developed. Bonding, cleaning, cutting, sizing, and forming parameters were established. These monotapes were then used to fabricate a 48 ply solid JT9D-7F 1st stage turbine blade. Core technology was then developed and first a 12 ply and then a 7 ply shell hollow airfoil was fabricated. As the fabrication technology advanced, additional airfoils incorporated further elements of sophistication, by introducing in sequence bonded root blocks, cross-plying, bi-metallic matrix, tip cap, trailing edge slots, and impingement inserts

Tungsten wire-reinforced superalloys for 1093 C (2000 F) turbine blade applications

Various combinations of fiber and matrix materials were fabricated and evaluated for the purpose of selecting a specific combination that exhibited the best overall properties for a turbine blade application. A total of seven matrix alloys, including Hastelloy X, Nimonic 80A, Inconel 600, Inconel 625, IN-102, FeCrA1Y, were investigated reinforced with either 218CS tungsten, or W-Hf-C fibers. Based on preliminary screening studies, FeCrA1Y, Inconel 600 and Inconel 625 matrix composites systems were selected for extended thermal cycle tests and for property evaluations which included stress rupture, impact, and oxidation resistance. Of those investigated, the FeCrA1Y matrix composite system exhibited the best overall properties required for a turbine blade application. The W-Hf-C/FeCrA1Y system was selected for further property evaluation. Tensile strength values of up to 724 MPa (105,000 psi) were obtained for this material at 982 C and 607 MPa at 1093 C

Channeling 5-min photospheric oscillations into the solar outer atmosphere through small-scale vertical magnetic flux tubes

We report two-dimensional MHD simulations which demonstrate that photospheric 5-min oscillations can leak into the chromosphere inside small-scale vertical magnetic flux tubes. The results of our numerical experiments are compatible with those inferred from simultaneous spectropolarimetric observations of the photosphere and chromosphere obtained with the Tenerife Infrared Polarimeter (TIP) at 10830 A. We conclude that the efficiency of energy exchange by radiation in the solar photosphere can lead to a significant reduction of the cut-off frequency and may allow for the propagation of the 5 minutes waves vertically into the chromosphere.Comment: accepted by ApJ

Additive Manufacturing of Energetic Materials and Its Uses in Various Applications

The work discussed in this document seeks to utilize traditional additive manufacturing techniques to selectively deposit energetic materials. The goal was to gain a fundamental understanding of how to use commonplace 2D inkjet printing and 3D fused deposition technology to selectively deposit reactive materials. Doing so provides the ability to manipulate the geometry, as well as composition, of the energetic material during the manufacturing process. Achieving this level manipulation and control has shown to be nontrivial, if not impossible, using traditional manufacturing methods. The ability to change the geometry of the energetic material at will greatly increases the ability of these energetic materials to be integrated with a wide range of systems, such as transient electronics. To create a transient electronic device, a destruction mechanism and an initiation system need to be integrated with electronic components. Experiments in this document investigate nanothermites for their ability to serve as this destruction mechanism. Nanothermites were prepared at various equivalence ratios and syringe deposited onto silicon substrates. The resultant destruction was shown to vary with the equivalence ratio of the material. A wide range of substrate destruction was demonstrated, varying from disintegration to only charring the wafer. Materials prepared near stoichiometric conditions were shown to disintegrate the silicon substrates completely. As the equivalence ratio was raised, less severe destruction was observed. The ability inkjet print these nanothermites provides the geometric control necessary to incorporate them into electronic components. An ink formulation process was explored in an attempt to create a fuel and an oxidizer ink, which could be inkjet printed simultaneously to create a nanothermite. Separate inks allow for the equivalence ratio, and therefore the resultant destruction, to be selectively tuned during the additive manufacturing process. Additionally, this gives the advantage of only needing two largely inert, shelf stable inks, instead of having to develop a new ink for every desired destruction level. Various candidate inks were formulated using different loadings and combinations of surfactants. Polyvinylpyrrolidone was shown to be the surfactant best suited for holding both aluminum and copper (II) oxide nanoparticles in suspension over time. These inks both showed reasonable shelf stability as well as viable reactivity when stoichiometric nanothermite samples were prepared using on-chip mixing. With respect to 3D printed energetic materials, fused deposition methods were used to print a fluoropolymer based energetic material which could be used as a multifunctional reactive structure. A reactive filament comprising of a polyvinylidene fluoride (PVDF) binder with 20% mass loading of aluminum (Al) was prepared using a commercial filament extruder and printed using a Makerbot Replicator 2X. The printing performance of the energetic samples was compared with standard 3D printing materials using metrics such as bead-to-bead adhesion and the surface quality of the printed samples. The reactivity and burning rates of the filaments and the printed samples were shown to be comparable. This result is imperative for fused deposition modeling to be used as a viable manufacturing method of energetic materials. In total, this document lays some of the groundwork necessary for additive manufacturing to be adopted as a viable method for the selective deposition of energetic materials. Going forward these methods can be used to integrate energetic materials in a manner not possible using traditional manufacturing methods