Space station power system

The major requirements and guidelines that affect the space station configuration and power system are explained. The evolution of the space station power system from the NASA program development-feasibility phase through the current preliminary design phase is described. Several early station concepts are described and linked to the present concept. Trade study selections of photovoltaic system technologies are described in detail. A summary of present solar dynamic and power management and distribution systems is also given

Status of space station power system

The major requirements and guidelines that affect the manned space station configuration and the power systems are explained. The evolution of the space station power system from the NASA program development feasibility phase through the current preliminary design phase is described. Several early station concepts are described and linked to the present concept. The recently completed phase B tradeoff study selections of photovoltaic system technologies are described. The present solar dynamic and power management and distribution systems are also summarized for completeness

Space Station Freedom Solar Array design development

The Space Station Freedom Solar Array Program is required to provide a 75 kW power module that uses eight solar array (SA) wings over a four-year period in low Earth orbit (LEO). Each wing will be capable of providing 23.4 kW at the 4-year design point. Lockheed Missles and Space Company, Inc. (LMSC) is providing the flexible substrate SAs that must survive exposure to the space environment, including atomic oxygen, for an operating life of fifteen years. Trade studies and development testing, important for evolving any design to maturity, are presently underway at LMSC on the flexible solar array. The trade study and development areas being investigated include solar cell module size, solar cell weld pads, panel stiffener frames, materials inherently resistant to atomic oxygen, and weight reduction design alternatives

Memory effects in attenuation and amplification quantum processes

With increasing communication rates via quantum channels, memory effects become unavoidable whenever the use rate of the channel is comparable to the typical relaxation time of the channel environment. We introduce a model of a bosonic memory channel, describing correlated noise effects in quantum-optical processes via attenuating or amplifying media. To study such a channel model, we make use of a proper set of collective field variables, which allows us to unravel the memory effects, mapping the n-fold concatenation of the memory channel to a unitarily equivalent, direct product of n single-mode bosonic channels. We hence estimate the channel capacities by relying on known results for the memoryless setting. Our findings show that the model is characterized by two different regimes, in which the cross correlations induced by the noise among different channel uses are either exponentially enhanced or exponentially reduced.Comment: 10 pages, 7 figures, close to the published versio

Forgetfulness of continuous Markovian quantum channels

The notion of forgetfulness, used in discrete quantum memory channels, is slightly weakened in order to be applied to the case of continuous channels. This is done in the context of quantum memory channels with Markovian noise. As a case study, we apply the notion of weak-forgetfulness to a bosonic memory channel with additive noise. A suitable encoding and decoding unitary transformation allows us to unravel the effects of the memory, hence the channel capacities can be computed using known results from the memoryless setting.Comment: 6 pages, 2 figures, comments are welcome. Minor corrections and acknoledgment adde

Impacto de Guadua paraguayana sobre remanescente de Floresta Ombrófila Mista Aluvial: uma abordagem biogeoquímica.

Guadua paraguayana Döll, um bambu nativo da porção meridional da América do Sul particularmente agressivo, está invadindo áreas de preservação permanente no segundo planalto paranaense, com supressão da vegetação instalada e modificações nos padrões de sucessão local. Após estabelecer sua autoecologia, para melhor avaliar seu impacto sobre um dos últimos remanescentes da Floresta Ombrófila Mista Aluvial (FOMA), principalmente na ciclagem de nutrientes e no fluxo de carbono orgânico para o ambiente, estudou-se a composição química da espécie, a produção e decomposição de serapilheira e a distribuição das raízes. A área em estudo (25º 13?20,8? S e 50º04?26,8? W, Ponta Grossa/PR) é uma planície de inundação degradada às margens do rio Tibagi. Os valores anuais de produção de serapilheira de G. paraguayana foram estimados em 7.500 kg/ha, com meia vida superior a 260 dias para os limbos e 360 dias para as bainhas foliares. No período analisado, as folhas retornaram ao ambiente 164,27 kg/ha de macronutrientes. Com base na concentração de carbono da folha, o fluxo de carbono orgânico da vegetação para o solo foi estimado em 2.800 kg/ha/ano. Em comparação com os valores de FOMA melhor preservada, a presença dominante desse bambu reduz a quantidade de nutrientes e de carbono devolvidos ao meio

Architecture of collaborating frameworks: simulation, visualisation, user interface and analysis

The Anaphe project is an ongoing effort to provide an Object Oriented software environment for data analysis in HENP experiments. A range of commercial and public domain libraries is used to cover basic functionalities; on top of these libraries a set of HENP-specific C++ class libraries for histogram management, fitting, plotting and ntuple-like data analysis has been developed. In order to comply with the user requirements for a command-line driven tool, we have chosen to use a scripting language (Python) as the front-end for a data analysis tool. The loose coupling provided by the consequent use of (AIDA compliant) Abstract Interfaces for each component in combination with the use of shared libraries for their implementation provides an easy integration of existing libraries into modern scripting languages thus allowing for rapid application development. This integration is simplified even further using a specialised toolkit (SWIG) to create "shadow classes" for the Python language, which map the definitions of the Abstract Interfaces almost at a one-to-one level. This paper will give an overview of the architecture and design choices and will present the current status and future developments of the project

Using strong conflicts to detect quality issues in component-based complex systems

The mainstream adoption of free and open source software (FOSS) has widely popularised notions like software packages or plugins, maintained in a distributed fashion and evolving at a very quick pace. Each of these components is equipped with metadata, such as dependencies, which define the other components it needs to function properly, and the incompatible components it cannot work with. In this paper, we introduce the notion of strong conflicts, defined from the component dependencies, that can be effectively computed. It gives important insights on the quality issues faced when adding or upgrading components in a given component repository, which is one of the facets of the predictable assembly problem.Our work contains concrete examples drawn from the world of GNU/Linux distributions, that validate the proposed approach. It also shows that the measures defined can be easily applied to the Eclipse world, or to any other coarse-grained software component model

A map of OMC-1 in CO 9-8

The distribution of 12C16O J=9-8 (1.037 THz) emission has been mapped in OMC-1 at 35 points with 84" resolution. This is the first map of this source in this transition and only the second velocity-resolved ground-based observation of a line in the terahertz frequency band. There is emission present at all points in the map, a region roughly 4' by 6' in size, with peak antenna temperature dropping only near the edges. Away from the Orion KL outflow, the velocity structure suggests that most of the emission comes from the OMC-1 photon-dominated region, with a typical linewidthof 3-6 km/s. Large velocity gradient modeling of the emission in J=9-8 and six lower transitions suggests that the lines originate in regions with temperatures around 120 K and densities of at least 10^(3.5) cm^(-3) near theta^(1) C Ori and at the Orion Bar, and from 70 K gas at around 10^(4) cm^(-3) southeast and west of the bar. These observations are among the first made with the 0.8 m Smithsonian Astrophysical Observatory Receiver Lab Telescope, a new instrument designed to observe at frequencies above 1 THz from an extremely high and dry site in northern Chile.Comment: Minor changes to references, text to match ApJ versio