Design, ancillary testing, analysis and fabrication data for the advanced composite stabilizer for Boeing 737 aircraft. Volume 1: Technical summary

The horizontal stabilizer of the 737 transport was redesigned. Five shipsets were fabricated using composite materials. Weight reduction greater than the 20% goal was achieved. Parts and assemblies were readily produced on production-type tooling. Quality assurance methods were demonstrated. Repair methods were developed and demonstrated. Strength and stiffness analytical methods were substantiated by comparison with test results. Cost data was accumulated in a semiproduction environment. FAA certification was obtained

Misfit strain relaxation and dislocation formation in supercritical strained silicon on virtual substrates

Relaxation of strained silicon on 20% linear graded virtual substrates was quantified using high resolution x-ray diffraction and a defect etching technique. The thickness of strained silicon was varied between 10 and 180 nm. Relaxation was observed in layers below the critical thickness but increased to only 2% relaxation in the thickest layers even with annealings up to 950 °C. Cross-sectional transmission electron microscopy revealed stacking faults present in layers thicker than 25 nm, and nucleated 90° Shockley partial dislocations forming microtwins in the thickest layer. These features are implicated in the impediment of the relaxation process

Observations of the Crab Nebula with H.E.S.S. Phase II

The High Energy Stereoscopic System (H.E.S.S.) phase I instrument was an array of four $100\,\mathrm{m}^2$ mirror area Imaging Atmospheric Cherenkov Telescopes (IACTs) that has very successfully mapped the sky at photon energies above $\sim 100\,$GeV. Recently, a $600\,\mathrm{m}^2$ telescope was added to the centre of the existing array, which can be operated either in standalone mode or jointly with the four smaller telescopes. The large telescope lowers the energy threshold for gamma-ray observations to several tens of GeV, making the array sensitive at energies where the Fermi-LAT instrument runs out of statistics. At the same time, the new telescope makes the H.E.S.S. phase II instrument. This is the first hybrid IACT array, as it operates telescopes of different size (and hence different trigger rates) and different field of view. In this contribution we present results of H.E.S.S. phase II observations of the Crab Nebula, compare them to earlier observations, and evaluate the performance of the new instrument with Monte Carlo simulations.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherland

Design, ancillary testing, analysis and fabrication data for the advanced composite stabilizer for Boeing 737 aircraft, volume 2

Results of tests conducted to demonstrate that composite structures save weight, possess long term durability, and can be fabricated at costs competitive with conventional metal structures are presented with focus on the use of graphite-epoxy in the design of a stabilizer for the Boeing 737 aircraft. Component definition, materials evaluation, material design properties, and structural elements tests are discussed. Fabrication development, as well as structural repair and inspection are also examined

On-the-fly memory compression for multibody algorithms.

Memory and bandwidth demands challenge developers of particle-based codes that have to scale on new architectures, as the growth of concurrency outperforms improvements in memory access facilities, as the memory per core tends to stagnate, and as communication networks cannot increase bandwidth arbitrary. We propose to analyse each particle of such a code to find out whether a hierarchical data representation storing data with reduced precision caps the memory demands without exceeding given error bounds. For admissible candidates, we perform this compression and thus reduce the pressure on the memory subsystem, lower the total memory footprint and reduce the data to be exchanged via MPI. Notably, our analysis and transformation changes the data compression dynamically, i.e. the choice of data format follows the solution characteristics, and it does not require us to alter the core simulation code

Detection of lithium in nearby young late-M dwarfs

Late M-type dwarfs in the solar neighborhood include a mixture of very low-mass stars and brown dwarfs which is difficult to disentangle due to the lack of constraints on their age such as trigonometric parallax, lithium detection and space velocity. We search for young brown dwarf candidates among a sample of 28 nearby late-M dwarfs with spectral types between M5.0 and M9.0, and we also search for debris disks around three of them. Based on theoretical models, we used the color $I-J$, the $J$-band absolute magnitude and the detection of the Li I 6708 $\AA$ doublet line as a strong constraint to estimate masses and ages of our targets. For the search of debris disks, we observed three targets at submillimeter wavelength of 850 $\mu$m. We report here the first clear detections of lithium absorption in four targets and a marginal detection in one target. Our mass estimates indicate that two of them are young brown dwarfs, two are young brown dwarf candidates and one is a young very low-mass star. The closest young field brown dwarf in our sample at only $\sim$15 pc is an excellent benchmark for further studying physical properties of brown dwarfs in the range 100$-$150 Myr. We did not detect any debris disks around three late-M dwarfs, and we estimated upper limits to the dust mass of debris disks around them.Comment: 10 pages, 5 figures, accepted for publication in Astronomy and Astrophysic

ELECTRON MICROSCOPY OF PLASMA-CELL TUMORS OF THE MOUSE : I. MPC-1 and X5563 Tumors

An electron microscope study was made of a series of transplanted MPC-1 plasma-cell tumors carried by BALB/c mice. Large numbers of particles similar in morphology to virus particles were present inside the endoplasmic reticulum of tumor plasma cells. Very few particles were seen outside the cells or in ultracentrifuged preparations of the plasma or ascites fluid. In very early tumors particles were occasionally seen free in the cytoplasm adjacent to finely granular material. In general, the distribution of these particles inside endoplasmic reticulum is similar in early and late tumors. A few transplanted X5563 tumors of C3H mice were also examined. Large numbers of particles were found in the region of the Golgi apparatus in late X5663 tumors. A newly described cytoplasmic structure of plasma cells, here called a "granular body," appears to be associated with the formation of the particles. Particles present in MPC-1 tumors are exclusively of a doughnut form, whereas some of those in the inclusions of the late X5563 tumors show a dense center. Normal plasma cells, produced by inoculation of a modified Freund adjuvant into BALB/c mice. have been compared morphologically with tumor plasma cells of both tumor lines