146 research outputs found
RSRM-11 (36OW011) ballistics mass properties (STS-35)
The propulsion performance and reconstructed mass properties data from Thiolol's RSRM-11 motors which were assigned to the STS-35 launch are contained. The Thiokol manufacturing designations for the motors were 360W011A/360W011B, which are referred to as RSRM-11A and RSRM-B, respectively. The launch of STS-35 occurred on 2 December 1990 at the Eastern Test Range (ETR). The data contained herein was input to the STS-35 Flight Evaluation Report. The SRM propellant, TP-H1148, is a composite type solid propellants, formulated of polybutediene acrylic acid, acryonitrile terpolymer binder, epoxy curing agent, ammonium perchlorate oxidizer, and aluminum powder fuel. A small amount of burning rate catalyst (iron oxide) was added to achieve the desired propellant burn rate. The propellant evaluation and raw material information for the RSRM-11 are included. The ballistic performance presented was based on the Operational Flight Instrumentation (OFI) 12.5 sample per second pressure data for the steady state and tail off portion of the pressure trace. Recent studies have shown that the transducers are affected by the measuring system at KSC and temperature gradients created by the igniter heaters. Therefore, an adjustment to the data from each transducer is made to make the initial reading match the atmospheric pressure at the time of launch
A multifactor approach to modelling the impact of wind energy on electricity spot prices
We introduce a three-factor model of electricity spot prices, consisting of a determinis- tic seasonality and trend function as well as short- and long-term stochastic components, and derive a formula for futures prices. The long-term component is modelled as a L ́evy process with increments belonging to the class of generalised hyperbolic distributions. We de- scribe the short-term factor by L ́evy semistationary processes: we start from a CARMA(2,1), i.e. a continous-time ARMA model, and generalise it by adding a short-memory stochastic volatility. We further modify the model by including the information about the wind energy production as an exogenous variable. We fit our models to German and Austrian data in- cluding spot and futures prices as well as the wind energy production and total load data. Empirical studies reveal that taking into account the impact of the wind energy generation on the prices improves the goodness of fit
Reflecting diffusions and hyperbolic Brownian motions in multidimensional spheres
Diffusion processes moving inside
spheres and reflecting orthogonally on their
surfaces are considered. The stochastic differential equations
governing the reflecting diffusions are presented and their kernels and
distributions explicitly derived. Reflection is obtained by means of the
inversion with respect to the sphere . The particular cases of
Ornstein-Uhlenbeck process and Brownian motion are examined in detail.
The hyperbolic Brownian motion on the Poincar\`e half-space is
examined in the last part of the paper and its reflecting counterpart within
hyperbolic spheres is studied. Finally a section is devoted to reflecting
hyperbolic Brownian motion in the Poincar\`e disc within spheres concentric
with
Spectrally stable nitrogen-vacancy centers in diamond formed by carbon implantation into thin microstructures
The nitrogen-vacancy center (NV) in diamond, with its exceptional spin
coherence and convenience in optical spin initialization and readout, is
increasingly used both as a quantum sensor and as a building block for quantum
networks. Employing photonic structures for maximizing the photon collection
efficiency in these applications typically leads to broadened optical
linewidths for the emitters, which are commonly created via nitrogen ion
implantation. With studies showing that only native nitrogen atoms contribute
to optically coherent NVs, a natural conclusion is to either avoid implantation
completely, or substitute nitrogen implantation by an alternative approach to
vacancy creation. Here, we demonstrate that implantation of carbon ions yields
a similar yield of NVs as implantation of nitrogen ions, and that it results in
NV populations with narrow optical linewidths and low charge-noise levels even
in thin diamond microstructures. We measure a median NV linewidth of 150 MHz
for structures thinner than 5 m, with no trend of increasing linewidths
down to the thinnest measured structure of 1.9 m. We propose a modified NV
creation procedure in which the implantation is carried out after instead of
before the diamond fabrication processes, and confirm our results in multiple
samples implanted with different ion energies and fluences
Random walks in the space of conformations of toy proteins
Monte Carlo dynamics of the lattice 48 monomers toy protein is interpreted as
a random walk in an abstract (discrete) space of conformations. To test the
geometry of this space, we examine the return probability , which is the
probability to find the polymer in the native state after Monte Carlo
steps, provided that it starts from the native state at the initial moment.
Comparing computational data with the theoretical expressions for for
random walks in a variety of different spaces, we show that conformational
spaces of polymer loops may have non-trivial dimensions and exhibit negative
curvature characteristic of Lobachevskii (hyperbolic) geometry.Comment: 4 pages, 3 figure
GREENET - An Early Stage Training Network in Enabling Technologies for Green Radio
International audienceIn this paper, we describe GREENET (an early stage training network in enabling technologies for green radio), which is a new project recently funded by the European Commission under the auspices of the 2010 Marie Curie People Programme. Through the recruitment and personalized training of 17 Early Stage Researchers (ESRs), in GREENET we are committed to the development of new disruptive technologies to address all aspects of energy efficiency in wireless networks, from the user devices to the core network infrastructure, along with the ways the devices and equipment interact with one another. Novel techniques at the physical, link, and network layers to reduce the energy consumption and carbon footprint of 4G devices will be investigated, such as Spatial Modulation (SM) for Multiple-Input-Multiple-Output (MIMO) systems, Cooperative Automatic Repeat reQuest (C-ARQ) protocols, and Network Coding (NC) for lossy networks. Furthermore, cooperation and cognition paradigms will be exploited as additional assets to improve the energy efficiency of wireless networks with the challenging but indispensable constraint of optimizing the system capacity without degrading the user's Quality-of-Service (QoS)
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