The extent of visual space inferred from perspective angles

PubMed Central

Erkelens, Casper J.

2015-01-01

Retinal images are perspective projections of the visual environment. Perspective projections do not explain why we perceive perspective in 3-D space. Analysis of underlying spatial transformations shows that visual space is a perspective transformation of physical space if parallel lines in physical space vanish at finite distance in visual space. Perspective angles, i.e., the angle perceived between parallel lines in physical space, were estimated for rails of a straight railway track. Perspective angles were also estimated from pictures taken from the same point of view. Perspective angles between rails ranged from 27% to 83% of their angular size in the retinal image. Perspective angles prescribe the distance of vanishing points of visual space. All computed distances were shorter than 6 m. The shallow depth of a hypothetical space inferred from perspective angles does not match the depth of visual space, as it is perceived. Incongruity between the perceived shape of a railway line on the one hand and the experienced ratio between width and length of the line on the other hand is huge, but apparently so unobtrusive that it has remained unnoticed. The incompatibility between perspective angles and perceived distances casts doubt on evidence for a curved visual space that has been presented in the literature and was obtained from combining judgments of distances and angles with physical positions. PMID:26034567

Zonal-flow dynamics from a phase-space perspective

NASA Astrophysics Data System (ADS)

Ruiz, D. E.; Parker, J. B.; Shi, E. L.; Dodin, I. Y.

2017-10-01

The wave kinetic equation (WKE) describing drift-wave (DW) turbulence is widely used in the studies of zonal flows (ZFs) emerging from DW turbulence. However, this formulation neglects the exchange of enstrophy between DWs and ZFs and also ignores effects beyond the geometrical-optics (GO) limit. Here we present a new theory that captures both of these effects, while still treating DW quanta (``driftons'') as particles in phase space. In this theory, the drifton dynamics is described by an equation of the Wigner-Moyal type, which is analogous to the phase-space formulation of quantum mechanics. The ``Hamiltonian'' and the ``dissipative'' parts of the DW-ZF interactions are clearly identified. Moreover, this theory can be interpreted as a phase-space representation of the second-order cumulant expansion (CE2). In the GO limit, this formulation features additional terms missing in the traditional WKE that ensure conservation of the total enstrophy of the system, in addition to the total energy, which is the only conserved invariant in previous theories based on the traditional WKE. Numerical simulations are presented to illustrate the importance of these additional terms. Supported by the U.S. DOE through Contract Nos. DE-AC02-09CH11466 and DE-AC52-07NA27344, by the NNSA SSAA Program through DOE Research Grant No. DE-NA0002948, and by the U.S. DOD NDSEG Fellowship through Contract No. 32-CFR-168a.

Space Station Freedom media handbook

NASA Technical Reports Server (NTRS)

1989-01-01

This handbook explains in lay terms, the work that is going on at the NASA Centers and contractors' plants in designing and developing the Space Station Freedom. It discusses the roles, responsibilities, and tasks required to build the Space Station Freedom's elements, systems, and components. New, required ground facilities are described, organized by NASA Center in order to provide a local angle for the media. Included are information on the historical perspective, international aspects, the utilization of the Space Station Freedom, a look at future possibilities, a description of the program, its management, program phases and milestones, and considerable information on the role of various NASA Centers, contractors and international partners. A list of abbreviations, a four-page glossary, and a list of NASA contacts are contained in the appendices.

Space-based optical image encryption.

PubMed

Chen, Wen; Chen, Xudong

2010-12-20

In this paper, we propose a new method based on a three-dimensional (3D) space-based strategy for the optical image encryption. The two-dimensional (2D) processing of a plaintext in the conventional optical encryption methods is extended to a 3D space-based processing. Each pixel of the plaintext is considered as one particle in the proposed space-based optical image encryption, and the diffraction of all particles forms an object wave in the phase-shifting digital holography. The effectiveness and advantages of the proposed method are demonstrated by numerical results. The proposed method can provide a new optical encryption strategy instead of the conventional 2D processing, and may open up a new research perspective for the optical image encryption.

Non-Archimedean reaction-ultradiffusion equations and complex hierarchic systems

NASA Astrophysics Data System (ADS)

Zúñiga-Galindo, W. A.

2018-06-01

We initiate the study of non-Archimedean reaction-ultradiffusion equations and their connections with models of complex hierarchic systems. From a mathematical perspective, the equations studied here are the p-adic counterpart of the integro-differential models for phase separation introduced by Bates and Chmaj. Our equations are also generalizations of the ultradiffusion equations on trees studied in the 1980s by Ogielski, Stein, Bachas, Huberman, among others, and also generalizations of the master equations of the Avetisov et al models, which describe certain complex hierarchic systems. From a physical perspective, our equations are gradient flows of non-Archimedean free energy functionals and their solutions describe the macroscopic density profile of a bistable material whose space of states has an ultrametric structure. Some of our results are p-adic analogs of some well-known results in the Archimedean setting, however, the mechanism of diffusion is completely different due to the fact that it occurs in an ultrametric space.

Classical and quantum entropy of parton distributions

NASA Astrophysics Data System (ADS)

Hagiwara, Yoshikazu; Hatta, Yoshitaka; Xiao, Bo-Wen; Yuan, Feng

2018-05-01

We introduce the semiclassical Wehrl entropy for the nucleon as a measure of complexity of the multiparton configuration in phase space. This gives a new perspective on the nucleon tomography. We evaluate the entropy in the small-x region and compare with the quantum von Neumann entropy. We also argue that the growth of entropy at small x is eventually slowed down due to the Pomeron loop effect.

The Space Optical Clock project: status and perspectives

NASA Astrophysics Data System (ADS)

Schiller, Stephan; Tino, Guglielmo M.; Sterr, Uwe; Lemonde, Pierre; Görlitz, Axel; Salomon, Christophe

The Space Optical Clocks project aims at operating lattice clocks on the ISS for tests of funda-mental physics and for providing high-accuracy comparisons of future terrestrial optical clocks. A pre-phase-A study (2007-10), funded partially by ESA and DLR, includes the implementa-tion of several optical lattice clock systems using Strontium and Ytterbium as atomic systems and their characterization. Subcomponents of clock demonstrators with the added specification of transportability and using techniques that are suitable for later space use, such as all-solid-state lasers, low power consumption, and compact dimensions, have been developed and are being validated. The talk will give a brief overview over the achieved results and outline future developments.

Perspective: Composition–structure–property mapping in high-throughput experiments: Turning data into knowledge

DOE PAGES

Hattrick-Simpers, Jason R.; Gregoire, John M.; Kusne, A. Gilad

2016-05-26

With their ability to rapidly elucidate composition-structure-property relationships, high-throughput experimental studies have revolutionized how materials are discovered, optimized, and commercialized. It is now possible to synthesize and characterize high-throughput libraries that systematically address thousands of individual cuts of fabrication parameter space. An unresolved issue remains transforming structural characterization data into phase mappings. This difficulty is related to the complex information present in diffraction and spectroscopic data and its variation with composition and processing. Here, we review the field of automated phase diagram attribution and discuss the impact that emerging computational approaches will have in the generation of phase diagrams andmore » beyond.« less

Space-time thermodynamics of the glass transition

NASA Astrophysics Data System (ADS)

Merolle, Mauro; Garrahan, Juan P.; Chandler, David

2005-08-01

We consider the probability distribution for fluctuations in dynamical action and similar quantities related to dynamic heterogeneity. We argue that the so-called “glass transition” is a manifestation of low action tails in these distributions where the entropy of trajectory space is subextensive in time. These low action tails are a consequence of dynamic heterogeneity and an indication of phase coexistence in trajectory space. The glass transition, where the system falls out of equilibrium, is then an order-disorder phenomenon in space-time occurring at a temperature Tg, which is a weak function of measurement time. We illustrate our perspective ideas with facilitated lattice models and note how these ideas apply more generally. Author contributions: M.M., J.P.G., and D.C. performed research and wrote the paper.

Quantum work in the Bohmian framework

NASA Astrophysics Data System (ADS)

Sampaio, R.; Suomela, S.; Ala-Nissila, T.; Anders, J.; Philbin, T. G.

2018-01-01

At nonzero temperature classical systems exhibit statistical fluctuations of thermodynamic quantities arising from the variation of the system's initial conditions and its interaction with the environment. The fluctuating work, for example, is characterized by the ensemble of system trajectories in phase space and, by including the probabilities for various trajectories to occur, a work distribution can be constructed. However, without phase-space trajectories, the task of constructing a work probability distribution in the quantum regime has proven elusive. Here we use quantum trajectories in phase space and define fluctuating work as power integrated along the trajectories, in complete analogy to classical statistical physics. The resulting work probability distribution is valid for any quantum evolution, including cases with coherences in the energy basis. We demonstrate the quantum work probability distribution and its properties with an exactly solvable example of a driven quantum harmonic oscillator. An important feature of the work distribution is its dependence on the initial statistical mixture of pure states, which is reflected in higher moments of the work. The proposed approach introduces a fundamentally different perspective on quantum thermodynamics, allowing full thermodynamic characterization of the dynamics of quantum systems, including the measurement process.

The Perspective Structure of Visual Space

PubMed Central

2015-01-01

Luneburg’s model has been the reference for experimental studies of visual space for almost seventy years. His claim for a curved visual space has been a source of inspiration for visual scientists as well as philosophers. The conclusion of many experimental studies has been that Luneburg’s model does not describe visual space in various tasks and conditions. Remarkably, no alternative model has been suggested. The current study explores perspective transformations of Euclidean space as a model for visual space. Computations show that the geometry of perspective spaces is considerably different from that of Euclidean space. Collinearity but not parallelism is preserved in perspective space and angles are not invariant under translation and rotation. Similar relationships have shown to be properties of visual space. Alley experiments performed early in the nineteenth century have been instrumental in hypothesizing curved visual spaces. Alleys were computed in perspective space and compared with reconstructed alleys of Blumenfeld. Parallel alleys were accurately described by perspective geometry. Accurate distance alleys were derived from parallel alleys by adjusting the interstimulus distances according to the size-distance invariance hypothesis. Agreement between computed and experimental alleys and accommodation of experimental results that rejected Luneburg’s model show that perspective space is an appropriate model for how we perceive orientations and angles. The model is also appropriate for perceived distance ratios between stimuli but fails to predict perceived distances. PMID:27648222

Legacy of the Space Shuttle from an Aerodynamic and Aerothermodynamic Perspective

NASA Technical Reports Server (NTRS)

Martin, Fred W.

2011-01-01

The development of the Space Shuttle Orbiter thermal protection system heating environment is described from a design stand point that began in the early 1970s. The desire for a light weight, reusable heat shield required the development of new technology, relative to previous manned spacecraft, and a systems approach to the design of the vehicle, entry guidance, and thermal protection system. Several unanticipated issues had to be resolved in both the entry and ascent phases of flight, which are discussed at a high level. During the life of the Program, significant improvements in computing power and numerical methods have been applied to Space Shuttle aerodynamic and aerothermodynamic issues, with the Shuttle Program often being the motivation, and or sponsor of the analysis development.

Spatiotemporal characterization of ultrashort optical vortex pulses

NASA Astrophysics Data System (ADS)

Miranda, Miguel; Kotur, Marija; Rudawski, Piotr; Guo, Chen; Harth, Anne; L'Huillier, Anne; Arnold, Cord L.

2017-12-01

We use a spiral phase plate to generate few-cycle optical vortices from an ultrafast titanium:sapphire oscillator and characterize them in the spatiotemporal domain with a recently introduced technique based on spatially resolved Fourier transform spectrometry. The performance of this simple approach to the generation of optical vortices is analysed from a wavelength-dependent perspective as well as in the spatiotemporal domain, allowing us to characterize ultrashort vortex pulses in space, frequency and time.

Projecting light beams with 3D waveguide arrays

NASA Astrophysics Data System (ADS)

Crespi, Andrea; Bragheri, Francesca

2017-01-01

Free-space light beams with complex intensity patterns, or non-trivial phase structure, are demanded in diverse fields, ranging from classical and quantum optical communications, to manipulation and imaging of microparticles and cells. Static or dynamic spatial light modulators, acting on the phase or intensity of an incoming light wave, are the conventional choices to produce beams with such non-trivial characteristics. However, interfacing these devices with optical fibers or integrated optical circuits often requires difficult alignment or cumbersome optical setups. Here we explore theoretically and with numerical simulations the potentialities of directly using the output of engineered three-dimensional waveguide arrays, illuminated with linearly polarized light, to project light beams with peculiar structures. We investigate through a collection of illustrative configurations the far field distribution, showing the possibility to achieve orbital angular momentum, or to produce elaborate intensity or phase patterns with several singularity points. We also simulate the propagation of the projected beam, showing the possibility to concentrate light. We note that these devices should be at reach of current technology, thus perspectives are open for the generation of complex free-space optical beams from integrated waveguide circuits.

The architect's perspective on the tour and map perspective.

PubMed

Papadopoulou, Athina

2015-09-01

Literature in linguistics suggests that when people are asked to provide an oral spatial description, they usually provide a body-centered narrative; they adopt a Tour Perspective, that is, an imaginary tour of the space rather than a Map Perspective, that is, a description focused on spatial relations as seen from above (Linde and Labov in Language 51(1):924-939, 1975; Howald in Discursive constraints on space in narrative: evidence from guilty plea discourse, eVox 3, 2009). I conducted a pilot experiment to address the following questions: Does the formal knowledge of architects--their familiarity with plan drawings and maps--override the tendency to adopt the tour perspective? Does the tour perspective depend on the actual experience of space? Twenty-two graduate students in architecture were asked to respond to the following questions: (1) "Can you describe the layout of your apartment?" (2) "Can you describe the layout of an ideal apartment?" In the responses to the first question most participants used the tour perspective. In the responses to the second question most participants used the map perspective. The results provide evidence that architects' formal knowledge does not override the preference of the tour perspective in descriptions of experienced space. Moreover, that the tour perspective is associated with the actual experience of space.

Freezing Coherent Field Growth in a Cavity by the Quantum Zeno Effect

NASA Astrophysics Data System (ADS)

Bernu, J.; Deléglise, S.; Sayrin, C.; Kuhr, S.; Dotsenko, I.; Brune, M.; Raimond, J. M.; Haroche, S.

2008-10-01

We have frozen the coherent evolution of a field in a cavity by repeated measurements of its photon number. We use circular Rydberg atoms dispersively coupled to the cavity mode for an absorption-free photon counting. These measurements inhibit the growth of a field injected in the cavity by a classical source. This manifestation of the quantum Zeno effect illustrates the backaction of the photon number determination onto the field phase. The residual growth of the field can be seen as a random walk of its amplitude in the two-dimensional phase space. This experiment sheds light onto the measurement process and opens perspectives for active quantum feedback.

Perspectives on Global and Regional Security and Implications of Nuclear and Space Technologies: U.S.-Brazil Strategic Dialogue, Phase 2 Report

DTIC Science & Technology

2014-10-01

its leadership of the regional opposition to the U.S.- Colombian anti-drug trafficking and terrorism partnership. Brazil has been critical of U.S... legislative action. There is no system for the President to push through legislation , as there is in the United States. All bills must go through both...the development of the defense industry. The political implications are that legislation can easily be halted or speeded along, based on the

Perspectives on the neuroscience of cognition and consciousness.

PubMed

Werner, Gerhard

2007-01-01

The origin and current use of the concepts of computation, representation and information in Neuroscience are examined and conceptual flaws are identified which vitiate their usefulness for addressing the problem of the neural basis of Cognition and Consciousness. In contrast, a convergence of views is presented to support the characterization of the Nervous System as a complex dynamical system operating in a metastable regime, and capable of evolving to configurations and transitions in phase space with potential relevance for Cognition and Consciousness.

Characterizing air quality data from complex network perspective.

PubMed

Fan, Xinghua; Wang, Li; Xu, Huihui; Li, Shasha; Tian, Lixin

2016-02-01

Air quality depends mainly on changes in emission of pollutants and their precursors. Understanding its characteristics is the key to predicting and controlling air quality. In this study, complex networks were built to analyze topological characteristics of air quality data by correlation coefficient method. Firstly, PM2.5 (particulate matter with aerodynamic diameter less than 2.5 μm) indexes of eight monitoring sites in Beijing were selected as samples from January 2013 to December 2014. Secondly, the C-C method was applied to determine the structure of phase space. Points in the reconstructed phase space were considered to be nodes of the network mapped. Then, edges were determined by nodes having the correlation greater than a critical threshold. Three properties of the constructed networks, degree distribution, clustering coefficient, and modularity, were used to determine the optimal value of the critical threshold. Finally, by analyzing and comparing topological properties, we pointed out that similarities and difference in the constructed complex networks revealed influence factors and their different roles on real air quality system.

Parts Selection for Space Systems - An Overview and Radiation Perspective

NASA Technical Reports Server (NTRS)

LaBel, Kenneth A.

2008-01-01

This viewgraph presentation describes the selection of electronic parts for aerospace systems from a space radiation perspective. The topics include: 1) The Trade Space Involved with Part Selection; 2) Understanding Risk; 3) Technical/Design Aspects; 4) Programmatic Overview; 5) Radiation Perspective; 6) Reliability Considerations; 7) An Example Ad hoc Battle; and 8) Sources of Radiation Data.

Technology Challenges and Opportunities for Very Large In-Space Structural Systems

NASA Technical Reports Server (NTRS)

Belvin, W. Keith; Dorsey, John T.; Watson, Judith J.

2009-01-01

Space solar power satellites and other large space systems will require creative and innovative concepts in order to achieve economically viable designs. The mass and volume constraints of current and planned launch vehicles necessitate highly efficient structural systems be developed. In addition, modularity and in-space deployment/construction will be enabling design attributes. While current space systems allocate nearly 20 percent of the mass to the primary structure, the very large space systems of the future must overcome subsystem mass allocations by achieving a level of functional integration not yet realized. A proposed building block approach with two phases is presented to achieve near-term solar power satellite risk reduction with accompanying long-term technology advances. This paper reviews the current challenges of launching and building very large space systems from a structures and materials perspective utilizing recent experience. Promising technology advances anticipated in the coming decades in modularity, material systems, structural concepts, and in-space operations are presented. It is shown that, together, the current challenges and future advances in very large in-space structural systems may provide the technology pull/push necessary to make solar power satellite systems more technically and economically feasible.

Comparing artistic and geometrical perspective depictions of space in the visual field

PubMed Central

Baldwin, Joseph; Burleigh, Alistair; Pepperell, Robert

2014-01-01

Which is the most accurate way to depict space in our visual field? Linear perspective, a form of geometrical perspective, has traditionally been regarded as the correct method of depicting visual space. But artists have often found it is limited in the angle of view it can depict; wide-angle scenes require uncomfortably close picture viewing distances or impractical degrees of enlargement to be seen properly. Other forms of geometrical perspective, such as fisheye projections, can represent wider views but typically produce pictures in which objects appear distorted. In this study we created an artistic rendering of a hemispherical visual space that encompassed the full visual field. We compared it to a number of geometrical perspective projections of the same space by asking participants to rate which best matched their visual experience. We found the artistic rendering performed significantly better than the geometrically generated projections. PMID:26034563

Comparing artistic and geometrical perspective depictions of space in the visual field.

PubMed

Baldwin, Joseph; Burleigh, Alistair; Pepperell, Robert

2014-01-01

Which is the most accurate way to depict space in our visual field? Linear perspective, a form of geometrical perspective, has traditionally been regarded as the correct method of depicting visual space. But artists have often found it is limited in the angle of view it can depict; wide-angle scenes require uncomfortably close picture viewing distances or impractical degrees of enlargement to be seen properly. Other forms of geometrical perspective, such as fisheye projections, can represent wider views but typically produce pictures in which objects appear distorted. In this study we created an artistic rendering of a hemispherical visual space that encompassed the full visual field. We compared it to a number of geometrical perspective projections of the same space by asking participants to rate which best matched their visual experience. We found the artistic rendering performed significantly better than the geometrically generated projections.

Exploring the free energy surface using ab initio molecular dynamics

NASA Astrophysics Data System (ADS)

Samanta, Amit; Morales, Miguel A.; Schwegler, Eric

2016-04-01

Efficient exploration of configuration space and identification of metastable structures in condensed phase systems are challenging from both computational and algorithmic perspectives. In this regard, schemes that utilize a set of pre-defined order parameters to sample the relevant parts of the configuration space [L. Maragliano and E. Vanden-Eijnden, Chem. Phys. Lett. 426, 168 (2006); J. B. Abrams and M. E. Tuckerman, J. Phys. Chem. B 112, 15742 (2008)] have proved useful. Here, we demonstrate how these order-parameter aided temperature accelerated sampling schemes can be used within the Born-Oppenheimer and the Car-Parrinello frameworks of ab initio molecular dynamics to efficiently and systematically explore free energy surfaces, and search for metastable states and reaction pathways. We have used these methods to identify the metastable structures and reaction pathways in SiO2 and Ti. In addition, we have used the string method [W. E, W. Ren, and E. Vanden-Eijnden, Phys. Rev. B 66, 052301 (2002); L. Maragliano et al., J. Chem. Phys. 125, 024106 (2006)] within the density functional theory to study the melting pathways in the high pressure cotunnite phase of SiO2 and the hexagonal closed packed to face centered cubic phase transition in Ti.

Phase-Retrieval Uncertainty Estimation and Algorithm Comparison for the JWST-ISIM Test Campaign

NASA Technical Reports Server (NTRS)

Aronstein, David L.; Smith, J. Scott

2016-01-01

Phase retrieval, the process of determining the exitpupil wavefront of an optical instrument from image-plane intensity measurements, is the baseline methodology for characterizing the wavefront for the suite of science instruments (SIs) in the Integrated Science Instrument Module (ISIM) for the James Webb Space Telescope (JWST). JWST is a large, infrared space telescope with a 6.5-meter diameter primary mirror. JWST is currently NASA's flagship mission and will be the premier space observatory of the next decade. ISIM contains four optical benches with nine unique instruments, including redundancies. ISIM was characterized at the Goddard Space Flight Center (GSFC) in Greenbelt, MD in a series of cryogenic vacuum tests using a telescope simulator. During these tests, phase-retrieval algorithms were used to characterize the instruments. The objective of this paper is to describe the Monte-Carlo simulations that were used to establish uncertainties (i.e., error bars) for the wavefronts of the various instruments in ISIM. Multiple retrieval algorithms were used in the analysis of ISIM phase-retrieval focus-sweep data, including an iterativetransform algorithm and a nonlinear optimization algorithm. These algorithms emphasize the recovery of numerous optical parameters, including low-order wavefront composition described by Zernike polynomial terms and high-order wavefront described by a point-by-point map, location of instrument best focus, focal ratio, exit-pupil amplitude, the morphology of any extended object, and optical jitter. The secondary objective of this paper is to report on the relative accuracies of these algorithms for the ISIM instrument tests, and a comparison of their computational complexity and their performance on central and graphical processing unit clusters. From a phase-retrieval perspective, the ISIM test campaign includes a variety of source illumination bandwidths, various image-plane sampling criteria above and below the Nyquist- Shannon critical sampling value, various extended object sizes, and several other impactful effects.

A spacefaring people: Perspectives on early spaceflight

NASA Technical Reports Server (NTRS)

Roland, A.

1985-01-01

The early years of space flight are discussed. An historical perspective is offered. Satellites and politics, management of large scale technology, the state of the literature of space, the domestic and international ramifications of space activity, and rationales for space exploration are discussed.

Galactic Observations of Terahertz C+ (GOT C+): Inner Galaxy Survey

NASA Astrophysics Data System (ADS)

Yorke, Harold; Langer, William; Velusamy, T.; Pineda, J. L.; Goldsmith, P. F.; Li, D.

To understand the lifecycle of the interstellar gas and star formation we need detailed information about the diffuse atomic and diffuse molecular gas cloud properties. The ionized carbon [CII] 1.9 THz fine structure line is an important tracer of the atomic gas in the diffuse regions and the interface regions of atomic gas to molecular clouds. Furthermore, C+ is a major ISM coolant and among the Galaxy's strongest far-IR emission lines, and thus controls the thermal conditions throughout large parts of the Galaxy. Until now our knowledge of interstellar gas has been limited to the diffuse atomic phase traced by HI and to the dense molecular H2 phase traced by CO. However, we are missing an important phase of the ISM, called "dark gas" in which there is no or little, HI, and mostly molecular hydrogen but with insufficient shielding of UV to allow CO to form. C+ emission and absorption lines at 1.9 THz have the potential to trace such cloud transitions and evolution. Galactic Observations of the Terahertz C+ Line (GOT C+) is a Herschel Space Observatory Open Time Key Program to study the diffuse interstellar medium by sampling [CII] 1.9 THz line emission throughout the Galactic disk. We discuss the broader perspective of this survey and the first results of GOT C+ obtained during the Science Demonstration Phase (SDP) and Priority Science Phase (PSP) of HIFI, which focus on approximately 100 lines of sight in the inner galaxy. These observations are being carried out with the Herschel Space Observatory, which is an ESA cornerstone mission, with contributions from NASA. This research was conducted at the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration. JLP is a Caltech-JPL Postdoctoral Associate.

Analysis, Implementation and Considerations for Liquid Crystals as a Reconfigurable Antennas Solution (LiCRAS) for Space

NASA Astrophysics Data System (ADS)

Doyle, Derek

The space industry has predominantly relied on high gain reflector dish antenna apertures for performing communications, but is constantly investing in phase array antenna concepts to provide increased signal flexibility at reduced system costs in terms of finances and system resources. The problem with traditional phased arrays remains the significantly greater program cost and complexity added to the satellite by integrating arrays of antenna elements with dedicated amplifier and phase shifters to perform adaptive beam forming. Liquid Crystal Reflectarrays (LiCRas) offer some of the electrical beam forming capability of a phased array system with the component and design complexity in lines with a traditional reflector antenna aperture but without the risks associated with mechanical steering systems. The final solution is believed to be a hybrid approach that performs in between the boundaries set by the two current disparate approaches. Practical reflectarrays have been developed since the 90's as a means to control reflection of incident radiation off a flat structure that is electrically curved based on radiating elements and their reflection characteristics with tailored element phase delay. In the last decade several methods have been proposed to enable tunable reflectarrays where the electrical shape of the reflector can be steered by controlling the resonating properties of the elements on the reflector using a DC bias. These approaches range from complex fast switching MEMS and ferroelectric devices, to more robust but slower chemical changes. The aim of this work is to investigate the feasibility of a molecular transition approach in the form of liquid crystals which change permittivity based on the electrical field they are subjected to. In this work, particular attention will be paid to the impact of space environment on liquid crystal reflectarray materials and reflector architectures. Of particular interest are the effects on performance induced by the temperature extremes of space and the electromagnetic particle environment. These two items tend to drive much of the research and development for various space technologies and based on these physical influences, assertions can be made toward the space worthiness of such a material approach and can layout future R&D; needs to make certain LC RF devices feasible for space use. Moreover, in this work the performance metrics of such a technology will be addressed along with methods of construction from a space perspective where specific design considerations must be made based on the extreme environment that a typical space asset must endure.

Role and regulation of sigma S in general resistance conferred by low-shear simulated microgravity in Escherichia coli.

PubMed

Lynch, S V; Brodie, E L; Matin, A

2004-12-01

Life on Earth evolved in the presence of gravity, and thus it is of interest from the perspective of space exploration to determine if diminished gravity affects biological processes. Cultivation of Escherichia coli under low-shear simulated microgravity (SMG) conditions resulted in enhanced stress resistance in both exponential- and stationary-phase cells, making the latter superresistant. Given that microgravity of space and SMG also compromise human immune response, this phenomenon constitutes a potential threat to astronauts. As low-shear environments are encountered by pathogens on Earth as well, SMG-conferred resistance is also relevant to controlling infectious disease on this planet. The SMG effect resembles the general stress response on Earth, which makes bacteria resistant to multiple stresses; this response is sigma s dependent, irrespective of the growth phase. However, SMG-induced increased resistance was dependent on sigma s only in stationary phase, being independent of this sigma factor in exponential phase. sigma s concentration was some 30% lower in exponential-phase SMG cells than in normal gravity cells but was twofold higher in stationary-phase SMG cells. While SMG affected sigma s synthesis at all levels of control, the main reasons for the differential effect of this gravity condition on sigma s levels were that it rendered the sigma protein less stable in exponential phase and increased rpoS mRNA translational efficiency. Since sigma s regulatory processes are influenced by mRNA and protein-folding patterns, the data suggest that SMG may affect these configurations.

High-order-harmonic generation from solids: The contributions of the Bloch wave packets moving at the group and phase velocities

NASA Astrophysics Data System (ADS)

Du, Tao-Yuan; Huang, Xiao-Huan; Bian, Xue-Bin

2018-01-01

We study numerically the Bloch electron wave-packet dynamics in periodic potentials to simulate laser-solid interactions. We introduce an alternative perspective in the coordinate space combined with the motion of the Bloch electron wave packets moving at group and phase velocities under the laser fields. This model interprets the origins of the two contributions (intra- and interband transitions) in the high-order harmonic generation (HHG) processes by investigating the local and global behaviours of the wave packets. It also elucidates the underlying physical picture of the HHG intensity enhancement by means of carrier-envelope phase, chirp, and inhomogeneous fields. It provides a deep insight into the emission of high-order harmonics from solids. This model is instructive for experimental measurements and provides an alternative avenue to distinguish mechanisms of the HHG from solids in different laser fields.

Femtoscopy as a tool for studying phase transition phenomena at STAR/BES energies in context of femtoscopic analysis at NICA

NASA Astrophysics Data System (ADS)

Wielanek, D.

2017-08-01

Femtoscopy is a tool to study the space-time evolution of hot and dense matter during high energy collision by using two-particle correlations. The femtoscopic and flow measurements at RHIC and LHC energies are well reproduced by the hydrodynamics models that contains equation of state (EoS) with crossover type transition from Quark-Gluon Plasma to hadron gas phase. Similar studies where performed at AGS and SPS accelerators and was performed in Beam Energy Scan (BES) program at Relativistic Heavy Ion Collider for exploring phase diagram of QCD matter. I present the femtoscopic observables calculated for Au-Au collisions at √sNN = 7:7 - 62:4 GeV calculated from viscous hydro + cascade model vHLLE+UrQMD with two types of EoSs - one that correspond to 1st order phase transition (PT) and second that correspond to crossover PT. I also discuss perspectives of femtoscopic measurements at NICA energy scale √sNN = 4 - 11 GeV.1

Mars Express Interplanetary Navigation from Launch to Mars Orbit Insertion: The JPL Experience

NASA Technical Reports Server (NTRS)

Han, Dongsuk; Highsmith, Dolan; Jah, Moriba; Craig, Diane; Border, James; Kroger, Peter

2004-01-01

The National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) played a significant role in supporting the safe arrival of the European Space Agency (ESA) Mars Express (MEX) orbiter to Mars on 25 December 2003. MEX mission is an international collaboration between member nations of the ESA and NASA, where NASA is supporting partner. JPL's involvement included providing commanding and tracking service with JPL's Deep Space Network (DSN), in addition to navigation assurance. The collaborative navigation effort between European Space Operations Centre (ESOC) and JPL is the first since ESA's last deep space mission, Giotto, and began many years before the MEX launch. This paper discusses the navigational experience during the cruise and final approach phase of the mission from JPL's perspective. Topics include technical challenges such as orbit determination using non-DSN tracking data and media calibrations, and modeling of spacecraft physical properties for accurate representation of non-gravitational dynamics. Also mentioned in this paper is preparation and usage of DSN Delta Differential Oneway Range ((Delta)DOR) measurements, a key element to the accuracy of the orbit determination.

Diamond cubic phase of monoolein and water as an amphiphilic matrix for electrophoresis of oligonucleotides.

PubMed

Carlsson, Nils; Winge, Ann-Sofie; Engström, Sven; Akerman, Björn

2005-10-06

We used a cubic liquid crystal formed by the nonionic monoglyceride monoolein and water as a porous matrix for the electrophoresis of oligonucleotides. The diamond cubic phase is thermodynamically stable when in contact with a water-rich phase, which we exploit to run the electrophoresis in the useful submarine mode. Oligonucleotides are separated according to size and secondary structure by migration through the space-filling aqueous nanometer pores of the regular liquid crystal, but the comparatively slow migration means the cubic phase will not be a replacement for the conventional DNA gels. However, our demonstration that the cubic phase can be used in submarine electrophoresis opens up the possibility for a new matrix for electrophoresis of amphiphilic molecules. From this perspective, the results on the oligonucleotides show that water-soluble particles of nanometer size, typical for the hydrophilic parts of membrane-bound proteins, may be a useful separation motif. A charged contamination in the commercial sample of monoolein, most likely oleic acid that arises from its hydrolysis, restricts useful buffer conditions to a pH below 5.6.

Micro- to macroscale perspectives on space plasmas

NASA Technical Reports Server (NTRS)

Eastman, Timothy E.

1993-01-01

The Earth's magnetosphere is the most accessible of natural collisionless plasma environments; an astrophysical plasma 'laboratory'. Magnetospheric physics has been in an exploration phase since its origin 35 years ago but new coordinated, multipoint observations, theory, modeling, and simulations are moving this highly interdisciplinary field of plasma science into a new phase of synthesis and understanding. Plasma systems are ones in which binary collisions are relatively negligible and collective behavior beyond the microscale emerges. Most readily accessible natural plasma systems are collisional and nearest-neighbor classical interactions compete with longer-range plasma effects. Except for stars, most space plasmas are collisionless, however, and the effects of electrodynamic coupling dominate. Basic physical processes in such collisionless plasmas occur at micro-, meso-, and macroscales that are not merely reducible to each other in certain crucial ways as illustrated for the global coupling of the Earth's magnetosphere and for the nonlinear dynamics of charged particle motion in the magnetotail. Such global coupling and coherence makes the geospace environment, the domain of solar-terrestrial science, the most highly coupled of all physical geospheres.

Perception of Peripersonal and Interpersonal Space in Patients with Restrictive-type Anorexia.

PubMed

Nandrino, Jean-Louis; Ducro, Claire; Iachini, Tina; Coello, Yann

2017-05-01

This study examines whether the perception of peripersonal action-space and interpersonal social-space is modified in patients with restrictive-type anorexia in two experimental conditions using videos. First, participants stopped the video of an approaching stimulus when they felt the distance to be comfortable for interacting with it (first-person perspective). Second, participants stopped the video when an observed individual approaching a stimulus, or being approached by it, was at a comfortable distance (third-person perspective). In the first-person perspective, the results showed an estimation of peripersonal space that did not differ from controls when an object was approaching and an increase in interpersonal space compared with controls when a male or female individual was approaching. In the third-person perspective, both individual-object and individual-individual distances were larger in anorexic patients. These results indicate a specific deficit in adjusting interpersonal distances in both the first-person and third-person perspectives. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

All-angle Negative Reflection with An Ultrathin Acoustic Gradient Metasurface: Floquet-Bloch Modes Perspective and Experimental Verification.

PubMed

Liu, Bingyi; Zhao, Jiajun; Xu, Xiaodong; Zhao, Wenyu; Jiang, Yongyuan

2017-10-23

Metasurface with gradient phase response offers new alternative for steering the propagation of waves. Conventional Snell's law has been revised by taking the contribution of local phase gradient into account. However, the requirement of momentum matching along the metasurface sets its nontrivial beam manipulation functionality within a limited-angle incidence. In this work, we theoretically and experimentally demonstrate that the acoustic gradient metasurface supports the negative reflection for all-angle incidence. The mode expansion theory is developed to help understand how the gradient metasurface tailors the incident beams, and the all-angle negative reflection occurs when the first negative order Floquet-Bloch mode dominates inside the metasurface slab. The coiling-up space structures are utilized to build desired acoustic gradient metasurface, and the all-angle negative reflections have been perfectly verified by experimental measurements. Our work offers the Floquet-Bloch modes perspective for qualitatively understanding the reflection behaviors of the acoustic gradient metasurface, and the all-angle negative reflection characteristic possessed by acoustic gradient metasurface could enable a new degree of the acoustic wave manipulating and be applied in the functional diffractive acoustic elements, such as the all-angle acoustic back reflector.

SPACE MEDICINE and Medical Operations Overview

NASA Technical Reports Server (NTRS)

Dervay, Joe

2009-01-01

This presentation is an overview of the function of the work of the Space Medicine & Health Care Systems Office. The objective of the medical operations is to ensure the health, safety and well being of the astronaut corps and ground support team during all phases of space flight. There are many issues that impact the health of the astronauts. Some of them are physiological, and others relate to behavior, psychological issues and issues of the environment of space itself. Reviews of the medical events that have affected both Russian, and Americans while in space are included. Some views of shuttle liftoff, and ascent, the medical training aboard NASA's KC-135 and training in weightlessness, the Shuttle Orbiter Medical system (SOMS), and some of the medical equipment are included. Also included are a graphs showing Fluid loading countermeasures, and vertical pursuit tracking with head and eye. The final views are representations of the future crew exploration vehicle (CEV) approaching the International Space Station, and the moon, and a series of perspective representations of the earth in comparison to the other planets and the Sun, the Sun in relation to other stars, and a view of where in the galaxy the Sun is.

Novel Perspectives on the Characterization of Species-Dependent Optical Signatures of Bacterial Colonies by Digital Holography.

PubMed

Buzalewicz, Igor; Kujawińska, Małgorzata; Krauze, Wojciech; Podbielska, Halina

2016-01-01

The use of light diffraction for the microbiological diagnosis of bacterial colonies was a significant breakthrough with widespread implications for the food industry and clinical practice. We previously confirmed that optical sensors for bacterial colony light diffraction can be used for bacterial identification. This paper is focused on the novel perspectives of this method based on digital in-line holography (DIH), which is able to reconstruct the amplitude and phase properties of examined objects, as well as the amplitude and phase patterns of the optical field scattered/diffracted by the bacterial colony in any chosen observation plane behind the object from single digital hologram. Analysis of the amplitude and phase patterns inside a colony revealed its unique optical properties, which are associated with the internal structure and geometry of the bacterial colony. Moreover, on a computational level, it is possible to select the desired scattered/diffracted pattern within the entire observation volume that exhibits the largest amount of unique, differentiating bacterial features. These properties distinguish this method from the already proposed sensing techniques based on light diffraction/scattering of bacterial colonies. The reconstructed diffraction patterns have a similar spatial distribution as the recorded Fresnel patterns, previously applied for bacterial identification with over 98% accuracy, but they are characterized by both intensity and phase distributions. Our results using digital holography provide new optical discriminators of bacterial species revealed in one single step in form of new optical signatures of bacterial colonies: digital holograms, reconstructed amplitude and phase patterns, as well as diffraction patterns from all observation space, which exhibit species-dependent features. To the best of our knowledge, this is the first report on bacterial colony analysis via digital holography and our study represents an innovative approach to the subject.

Novel Perspectives on the Characterization of Species-Dependent Optical Signatures of Bacterial Colonies by Digital Holography

PubMed Central

Buzalewicz, Igor; Kujawińska, Małgorzata; Krauze, Wojciech; Podbielska, Halina

2016-01-01

The use of light diffraction for the microbiological diagnosis of bacterial colonies was a significant breakthrough with widespread implications for the food industry and clinical practice. We previously confirmed that optical sensors for bacterial colony light diffraction can be used for bacterial identification. This paper is focused on the novel perspectives of this method based on digital in-line holography (DIH), which is able to reconstruct the amplitude and phase properties of examined objects, as well as the amplitude and phase patterns of the optical field scattered/diffracted by the bacterial colony in any chosen observation plane behind the object from single digital hologram. Analysis of the amplitude and phase patterns inside a colony revealed its unique optical properties, which are associated with the internal structure and geometry of the bacterial colony. Moreover, on a computational level, it is possible to select the desired scattered/diffracted pattern within the entire observation volume that exhibits the largest amount of unique, differentiating bacterial features. These properties distinguish this method from the already proposed sensing techniques based on light diffraction/scattering of bacterial colonies. The reconstructed diffraction patterns have a similar spatial distribution as the recorded Fresnel patterns, previously applied for bacterial identification with over 98% accuracy, but they are characterized by both intensity and phase distributions. Our results using digital holography provide new optical discriminators of bacterial species revealed in one single step in form of new optical signatures of bacterial colonies: digital holograms, reconstructed amplitude and phase patterns, as well as diffraction patterns from all observation space, which exhibit species-dependent features. To the best of our knowledge, this is the first report on bacterial colony analysis via digital holography and our study represents an innovative approach to the subject. PMID:26943121

A perspective on space robotics in Japan

NASA Technical Reports Server (NTRS)

Ohkami, Yoshiaki; Nakatani, Ichiro; Wakabayashi, Yasufumi; Iwata, Tsutomu

1994-01-01

This report summarizes the research and development status and perspective on space robotics in Japan. The R & D status emphasizes the current on-going projects at NASDA including the JEM Remote Manipulator System (JEMRMS) to be used on Space Station Freedom and the robotics experiments on Engineering Satellite 7 (ETS-7). As a future perspective, not only NASDA, but also ISAS and other government institutes have been promoting their own research in space robotics in order to support wide spread space activities in the future. Included in this future research is an autonomous satellite retrieval experiment, a dexterous robot experiment, an on-orbit servicing platform, an IVA robot, and several moon/planetary rovers proposed by NASDA or ISAS and other organizations.

Feasibility of a ring FEL at low emittance storage rings

NASA Astrophysics Data System (ADS)

Agapov, I.

2015-09-01

A scheme for generating coherent radiation at latest generation low emittance storage rings such as PETRA III at DESY (Balewski et al., 2004 [1]) is proposed. The scheme is based on focusing and subsequent defocusing of the electron beam in the longitudinal phase space at the undulator location. The expected performance characteristics are estimated for radiation in the wavelength range of 500-1500 eV. It is shown that the average brightness is increased by several orders of magnitude compared to spontaneous undulator radiation, which can open new perspectives for photon-hungry soft X-ray spectroscopy techniques.

Vehicle System Management Modeling in UML for Ares I

NASA Technical Reports Server (NTRS)

Pearson, Newton W.; Biehn, Bradley A.; Curry, Tristan D.; Martinez, Mario R.

2011-01-01

The Spacecraft & Vehicle Systems Department of Marshall Space Flight Center is responsible for modeling the Vehicle System Management for the Ares I vehicle which was a part of the now canceled Constellation Program. An approach to generating the requirements for the Vehicle System Management was to use the Unified Modeling Language technique to build and test a model that would fulfill the Vehicle System Management requirements. UML has been used on past projects (flight software) in the design phase of the effort but this was the first attempt to use the UML technique from a top down requirements perspective.

Fractional dynamics using an ensemble of classical trajectories

NASA Astrophysics Data System (ADS)

Sun, Zhaopeng; Dong, Hao; Zheng, Yujun

2018-01-01

A trajectory-based formulation for fractional dynamics is presented and the trajectories are generated deterministically. In this theoretical framework, we derive a new class of estimators in terms of confluent hypergeometric function (F11) to represent the Riesz fractional derivative. Using this method, the simulation of free and confined Lévy flight are in excellent agreement with the exact numerical and analytical results. In addition, the barrier crossing in a bistable potential driven by Lévy noise of index α is investigated. In phase space, the behavior of trajectories reveal the feature of Lévy flight in a better perspective.

Lessons Learned from the Advanced Topographic Laser Altimeter System

NASA Technical Reports Server (NTRS)

Garrison, Matt; Patel, Deepak; Bradshaw, Heather; Robinson, Frank; Neuberger, Dave

2016-01-01

The ICESat-2 Advanced Topographic Laser Altimeter System (ATLAS) instrument is an upcoming Earth Science mission focusing on the effects of climate change. The flight instrument passed all environmental testing at GSFC (Goddard Space Flight Center) and is now ready to be shipped to the spacecraft vendor for integration and testing. This presentation walks through the lessons learned from design, hardware, analysis and testing perspective. ATLAS lessons learned include general thermal design, analysis, hardware, and testing issues as well as lessons specific to laser systems, two-phase thermal control, and optical assemblies with precision alignment requirements.

Power of the Poincaré group: elucidating the hidden symmetries in focal conic domains.

PubMed

Alexander, Gareth P; Chen, Bryan Gin-Ge; Matsumoto, Elisabetta A; Kamien, Randall D

2010-06-25

Focal conic domains are typically the "smoking gun" by which smectic liquid crystalline phases are identified. The geometry of the equally spaced smectic layers is highly generic but, at the same time, difficult to work with. In this Letter we develop an approach to the study of focal sets in smectics which exploits a hidden Poincaré symmetry revealed only by viewing the smectic layers as projections from one-higher dimension. We use this perspective to shed light upon several classic focal conic textures, including the concentric cyclides of Dupin, polygonal textures, and tilt-grain boundaries.

Galactic Observations of Terahertz C+ (GOT C+): First Results: Inner Galaxy Survey

NASA Astrophysics Data System (ADS)

Langer, William; Velusamy, T.; Pineda, J. L.; Goldsmith, P. F.; Li, D.; Yorke, H. W.

2010-05-01

To understand the lifecycle of the interstellar gas and star formation we need detailed information about the diffuse atomic and diffuse molecular gas cloud properties. The ionized carbon [CII] 1.9 THz fine structure line is an important tracer of the atomic gas in the diffuse regions and the interface regions of atomic gas to molecular clouds. Furthermore, C+ is a major ISM coolant and among the Galaxy's strongest far-IR emission lines, and thus controls the thermal conditions throughout large parts of the Galaxy. Until now our knowledge of interstellar gas has been limited to the diffuse atomic phase traced by HI and to the dense molecular H2 phase traced by CO. However, we are missing an important phase of the ISM called "dark gas” in which there is no or little, HI, and mostly molecular hydrogen but with insufficient shielding of UV to allow CO to form. C+ emission and absorption lines at 1.9 THz have the potential to trace this gas. Galactic Observations of the Terahertz C+ Line (GOT C+) is a Herschel Space Observatory Open Time Key Program to study the diffuse interstellar medium by sampling [CII] 1.9 THz line emission throughout the Galactic disk. We discuss the broader perspective of this survey and the first results of GOT C+ obtained during the Science Demonstration Phase (SDP) and Priority Science Phase (PSP) of HIFI, which focus on approximately 100 lines of sight in the inner galaxy. This research was conducted at the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration.

Integrated Design Methodology for Highly Reliable Liquid Rocket Engine

NASA Astrophysics Data System (ADS)

Kuratani, Naoshi; Aoki, Hiroshi; Yasui, Masaaki; Kure, Hirotaka; Masuya, Goro

The Integrated Design Methodology is strongly required at the conceptual design phase to achieve the highly reliable space transportation systems, especially the propulsion systems, not only in Japan but also all over the world in these days. Because in the past some catastrophic failures caused some losses of mission and vehicle (LOM/LOV) at the operational phase, moreover did affect severely the schedule delays and cost overrun at the later development phase. Design methodology for highly reliable liquid rocket engine is being preliminarily established and investigated in this study. The sensitivity analysis is systematically performed to demonstrate the effectiveness of this methodology, and to clarify and especially to focus on the correlation between the combustion chamber, turbopump and main valve as main components. This study describes the essential issues to understand the stated correlations, the need to apply this methodology to the remaining critical failure modes in the whole engine system, and the perspective on the engine development in the future.

A spacefaring nation - Perspectives on American space history and policy

NASA Technical Reports Server (NTRS)

Collins, Martin J. (Editor); Fries, Sylvia D. (Editor)

1991-01-01

The present volume on perspectives on American space history and policy discusses decision-making, space science and scientific communities, postwar aeronautical research in the federal laboratory, and civilian and military remote sensing and reconnaissance. Attention is given to the interpenetration of science, technology, and politics; space 'sociology'; and space technology and planetary science from 1950 to 1985. Other topics addressed include the aeronautics infrastructure as it applies to aeronautics history, the Lewis Research Center and its transition to space, the relationship between NASA and the users of earth resources data, and methodology for researching a classified system for space reconnaissance.

A New 50 MHz Phased-Array Radar on Pohnpei: A Fresh Perspective on Equatorial Plasma Bubbles

NASA Astrophysics Data System (ADS)

Tsunoda, R. T.

2014-12-01

A new, phased-array antenna-steering capability has recently been added to an existing 50-MHz radar on Pohnpei, Federated States of Micronesia, in the central Pacific region. This radar, which we refer to as PAR-50, is capable of scanning in the vertical east-west plane, ±60° about the zenith. The alignment in the magnetic east-west direction allows detection of radar backscatter from small-scale irregularities that develop in the equatorial ionosphere, including those associated with equatorial plasma bubbles (EPBs). The coverage, about ±800 km in zonal distance, at an altitude of 500 km, is essentially identical to that provided by ALTAIR, a fully-steerable incoherent-scatter radar, which has been used in a number of studies of EPBs. Unlike ALTAIR, which has only been operated for several hours on a handful of selected nights, the PAR-50 has already been operated continuously, while performing repeated scans, since April 2014. In this presentation, we describe the PAR-50, then, compare it to ALTAIR and the Equatorial Atmospheric Radar (EAR); the latter is the only other phased-array system in use for equatorial studies. We then assess what we have learned about EPBs from backscatter radar measurements, and discuss how the PAR-50 can provide a fresh perspective to our understanding. Clearly, the ability to sort out the space-time ambiguities in EPB development from sequences of spatial maps of EPBs is crucial to our understanding of how EPBs develop.

Why It Is Hard to Make Use of New Learning Spaces: A Script Perspective

ERIC Educational Resources Information Center

Kollar, Ingo; Pilz, Florian; Fischer, Frank

2014-01-01

The authors argue that a script perspective can lead to a better understanding of learning in new learning spaces. Scripts can be understood as flexible, individual memory structures guiding our understanding and actions, but also as instructional interventions that help students use the affordances offered in new learning spaces. In study 1 (N =…

Challenges, developments and perspectives in intermittent ...

EPA Pesticide Factsheets

Although more than half the world's river networks comprise channels that periodically cease to flow and dry [intermittent rivers (IRs)], river ecology was largely developed from and for perennial systems. Ecological knowledge of IRs is rapidly increasing, so there is a need to synthesise this knowledge and deepen ecological understanding.In this Special Issue, we bring together 13 papers spanning observational case studies, field and laboratory experiments and reviews to guide research and management in this productive field of freshwater science. We summarise new developments in IR ecology, identify research gaps and needs, and address how the study of IRs as highly dynamic ecosystems informs ecological understanding more broadly.This series of articles reveals that contemporary IR ecology is a multifaceted and maturing field of research at the interface between aquatic and terrestrial ecology. This research contributes to fresh water and general ecology by testing concepts across a range of topics, including disturbance ecology, metacommunity ecology and coupled aquatic-terrestrial ecosystems.Drying affects flow continuity through time and flow connectivity across longitudinal, lateral and vertical dimensions of space, which aligns well with the recent emphasis of mainstream ecology on meta-system perspectives. Although most articles here focus on the wet phase, there is growing interest in dry phases, and in the terrestrial vegetation and invertebrate assemb

"Journal of Space Economics - theoretical and practical considerations"

NASA Astrophysics Data System (ADS)

Beldavs, VZ; Sommers, J.

2017-09-01

This paper will address theoretical and practical considerations for the emerging field of space economics and propose an editorial policy for a journal of space economics to provide a forum for the discussion of space economics issues. It is anticipated that initially the Journal of Space Economics will operate from two different nodes one offering a European perspective (University of Latvia) and the other a U.S. perspective (University of Wisconsin at Milwaukee). The first edition of the Journal of Space Economics will focus on issues likely to arise during the course of the International Lunar Decade 2020-2030.

Spacecraft Fire Safety: A Human Space Flight Program Perspective

NASA Technical Reports Server (NTRS)

Pedley, Michael D.

2003-01-01

This paper presents viewgraphs on the International Space Station's fire safety program from a human space flight perspective. The topics include: 1) Typical Manned Spacecraft Materials; 2) Typical Flammable Hardware Protection; 3) Materials Flammability; 4) Fire Retardants; 5) Nonflammable Foam Cushion Material; 6) Electrical Wire and Cable; 7) Russian Solid-Fuel Oxygen Generator (SFOG); 8) GOX Ignition Mechanisms; 9) Fire Detection; and 10) Fire Suppression.

Space solar cell technology development - A perspective

NASA Technical Reports Server (NTRS)

Scott-Monck, J.

1982-01-01

The developmental history of photovoltaics is examined as a basis for predicting further advances to the year 2000. Transistor technology was the precursor of solar cell development. Terrestrial cells were modified for space through changes in geometry and size, as well as the use of Ag-Ti contacts and manufacture of a p-type base. The violet cell was produced for Comsat, and involved shallow junctions, new contacts, and an enhanced antireflection coating for better radiation tolerance. The driving force was the desire by private companies to reduce cost and weight for commercial satellite power supplies. Liquid phase epitaxial (LPE) GaAs cells are the latest advancement, having a 4 sq cm area and increased efficiency. GaAs cells are expected to be flight ready in the 1980s. Testing is still necessary to verify production techniques and the resistance to electron and photon damage. Research will continue in CVD cell technology, new panel technology, and ultrathin Si cells.

Methane Hydrate in Confined Spaces: An Alternative Storage System.

PubMed

Borchardt, Lars; Casco, Mirian Elizabeth; Silvestre-Albero, Joaquin

2018-06-05

Methane hydrate inheres the great potential to be a nature-inspired alternative for chemical energy storage, as it allows to store large amounts of methane in a dense solid phase. The embedment of methane hydrate in the confined environment of porous materials can be capitalized for potential applications as its physicochemical properties, such as the formation kinetics or pressure and temperature stability, are significantly changed compared to the bulk system. We review this topic from a materials scientific perspective by considering porous carbons, silica, clays, zeolites, and polymers as host structures for methane hydrate formation. We discuss the contribution of advanced characterization techniques and theoretical simulations towards the elucidation of the methane hydrate formation and dissociation process within the confined space. We outline the scientific challenges this system is currently facing and look on possible future applications for this technology. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Magnetic conveyor belt for transporting and merging trapped atom clouds.

PubMed

Hänsel, W; Reichel, J; Hommelhoff, P; Hänsch, T W

2001-01-22

We demonstrate an integrated magnetic device which transports cold atoms near a surface with very high positioning accuracy. Time-dependent currents in a lithographic conductor pattern create a moving chain of potential wells; atoms are transported in these wells while remaining confined in all three dimensions. We achieve mean fluxes up to 10(6) s(-1) with a negligible heating rate. An extension of this device allows merging of atom clouds by unification of two Ioffe-Pritchard potentials. The unification, which we demonstrate experimentally, can be performed without loss of phase space density. This novel, all-magnetic atom manipulation offers exciting perspectives, such as trapped-atom interferometry.

Discovery.

ERIC Educational Resources Information Center

Smithsonian Institution, Washington, DC. National Air And Space Museum.

This material presents the historical perspectives of flight and student activities for grades K-3 prepared by the National Air and Space Museum (NASM) and National Aeronautics and Space Administration (NASA). Sections included are: (1) "Historical Perspective of Flight"; (2) "Discovery Vocabulary" (listing the terms found in the first section);…

Coiling of elastic rods from a geometric perspective

NASA Astrophysics Data System (ADS)

Jawed, Mohammad; Brun, Pierre-Thomas; Reis, Pedro

2015-03-01

We present results from a systematic numerical investigation of the pattern formation of coiling obtained when a slender elastic rod is deployed onto a moving substrate; a system known as the elastic sewing machine (ESM). The Discrete Elastic Rods method is employed to explore the parameter space, construct phase diagrams, identify their phase boundaries and characterize the morphology of the patterns. The nontrivial geometric nonlinearities are described in terms of the gravito-bending length and the deployment height. Our results are interpreted using a reduced geometric model for the evolution of the position of the contact point with the belt and the curvature of the rod in its neighborhood. This geometric model reproduces all of the coiling patterns of the ESM, which allows us to establish a universal link between our elastic problem and the analogous patterns obtained when depositing a viscous thread onto a moving surface; a well-known system referred to as the fluid mechanical sewing machine.

The eigenvalue problem in phase space.

PubMed

Cohen, Leon

2018-06-30

We formulate the standard quantum mechanical eigenvalue problem in quantum phase space. The equation obtained involves the c-function that corresponds to the quantum operator. We use the Wigner distribution for the phase space function. We argue that the phase space eigenvalue equation obtained has, in addition to the proper solutions, improper solutions. That is, solutions for which no wave function exists which could generate the distribution. We discuss the conditions for ascertaining whether a position momentum function is a proper phase space distribution. We call these conditions psi-representability conditions, and show that if these conditions are imposed, one extracts the correct phase space eigenfunctions. We also derive the phase space eigenvalue equation for arbitrary phase space distributions functions. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Cost of outpatient endoscopic sinus surgery from the perspective of the Canadian government: a time-driven activity-based costing approach.

PubMed

Au, Jennifer; Rudmik, Luke

2013-09-01

The time-driven activity-based costing (TD-ABC) method is a novel approach to quantify the costs of a complex system. The aim of this study was to apply the TD-ABC technique to define the overall cost of a routine outpatient endoscopic sinus surgery (ESS) from the perspective of the Canadian government payer. Costing perspective was the Canadian government payer. All monetary values are in Canadian dollars as of December 2012. Costs were obtained by contacting staff unions, reviewing purchasing databases and provincial physician fee schedules. Practical capacity time values were collected from the College and Association of Registered Nurses of Alberta. Capacity cost rates ($/min) were calculated for all staff, capital equipment, and hospital space. The overall cost for routine outpatient ESS was $3510.31. The cost per ESS case for each clinical pathway encounter was as follows: preoperative holding ($49.19); intraoperative ($3296.60); sterilization ($90.20); postanesthesia care unit ($28.64); and postoperative day ward ($45.68). The 3 major cost drivers were physician fees, disposable equipment, and nursing costs. The intraoperative phase contributed to 94.5% of the overall cost. This study applied the TD-ABC method to evaluate the cost of outpatient ESS from the perspective of the Canadian government payer and defined the overall cost to be $3510.31 per case. © 2013 ARS-AAOA, LLC.

Ethics case reflection sessions: Enablers and barriers.

PubMed

Bartholdson, Cecilia; Molewijk, Bert; Lützén, Kim; Blomgren, Klas; Pergert, Pernilla

2018-03-01

In previous research on ethics case reflection (ECR) sessions about specific cases, healthcare professionals in childhood cancer care were clarifying their perspectives on the ethical issue to resolve their main concern of consolidating care. When perspectives were clarified, consequences in the team included 'increased understanding', 'group strengthening' and 'decision grounding'. Additional analysis of the data was needed on conditions that could contribute to the quality of ECR sessions. The aim of this study was to explore conditions for clarifying perspectives during ECR sessions. Data were collected from observations and interviews and the results emerged from an inductive analysis using grounded theory. Participants and research context: Six observations during ECR sessions and 10 interviews were performed with healthcare professionals working in childhood cancer care and advanced paediatric homecare. Ethical considerations: The study was approved by a regional ethical review board. Participants were informed about their voluntary involvement and that they could withdraw their participation without explaining why. Two categories emerged: organizational enablers and barriers and team-related enablers and barriers. Organizational enablers and barriers included the following sub-categories: the timing of the ECR session, the structure during the ECR session and the climate during the ECR session. Sub-categories to team-related enablers and barriers were identified as space for inter-professional perspectives, varying levels of ethical skills and space for the patient's and the family's perspectives. Space for inter-professional perspectives included the dominance of a particular perspective that can result from hierarchical positions. The medical perspective is relevant for understanding the child's situation but should not dominate the ethical reflection. Conditions for ECR sessions have been explored and the new knowledge can be used when training facilitators as well as for those who organize/implement ECR sessions. Awareness of space for different perspectives, including the possible medical advantage over the nursing perspective, could reduce the somewhat unilateral attention and contribute to an inter-professionally shared reflection.

Anharmonic quantum mechanical systems do not feature phase space trajectories

NASA Astrophysics Data System (ADS)

Oliva, Maxime; Kakofengitis, Dimitris; Steuernagel, Ole

2018-07-01

Phase space dynamics in classical mechanics is described by transport along trajectories. Anharmonic quantum mechanical systems do not allow for a trajectory-based description of their phase space dynamics. This invalidates some approaches to quantum phase space studies. We first demonstrate the absence of trajectories in general terms. We then give an explicit proof for all quantum phase space distributions with negative values: we show that the generation of coherences in anharmonic quantum mechanical systems is responsible for the occurrence of singularities in their phase space velocity fields, and vice versa. This explains numerical problems repeatedly reported in the literature, and provides deeper insight into the nature of quantum phase space dynamics.

Orbital Debris: A Policy Perspective

NASA Technical Reports Server (NTRS)

Johnson, Nicholas L.

2007-01-01

A viewgraph presentation describing orbital debris from a policy perspective is shown. The contents include: 1) Voyage through near-Earth Space-animation; 2) What is Orbital Debris?; 3) Orbital Debris Detectors and Damage Potential; 4) Hubble Space Telescope; 5) Mir Space Station Solar Array; 6) International Space Station; 7) Space Shuttle; 8) Satellite Explosions; 9) Satellite Collisions; 10) NASA Orbital Debris Mitigation Guidelines; 11) International Space Station Jettison Policy; 12) Controlled/Uncontrolled Satellite Reentries; 13) Return of Space Objects; 14) Orbital Debris and U.S. National Space Policy; 15) U.S Government Policy Strategy; 16) Bankruptcy of the Iridium Satellite System; 17) Inter-Agency Space Debris Coordination Committee (IADC); 18) Orbital Debris at the United Nations; 19) Chinese Anti-satellite System; 20) Future Evolution of Satellite Population; and 21) Challenge of Orbital Debris

The perspectives of femtosecond imaging and spectroscopy of complex materials using electrons

NASA Astrophysics Data System (ADS)

Ruan, Chong-Yu; Duxbury, Phiilp M.; Berz, Martin

2014-09-01

The coexistence of various electronic and structural phases that are close in free-energy is a hallmark in strongly correlated electron systems with emergent properties, such as metal-insulator transition, colossal magnetoresistance, and high-temperature superconductivity. The cooperative phase transitions from one functional state to another can involve entanglements between the electronically and structurally ordered states, hence deciphering the fundamental mechanisms is generally difficult and remains very active in condensed matter physics and functional materials research. We outline the recent ultrafast characterizations of 2D charge-density wave materials, including the nonequilibrium electron dynamics unveiled by ultrafast optical spectroscopy-based techniques sensitive to the electronic order parameter. We also describe the most recent findings from ultrafast electron crystallography, which provide structural aspects to correlate lattice dynamics with electronic evolutions to address the two sides of a coin in the ultrafast switching of a cooperative state. Combining these results brings forth new perspectives and a fuller picture in understanding lightmatter interactions and various switching mechanisms in cooperative systems with many potential applications. We also discuss the prospects of implementing new ultrafast electron imaging as a local probe incorporated with femtosecond select-area diffraction, imaging and spectroscopy to provide a full scope of resolution to tackle the more challenging complex phase transitions on the femtosecond-nanometer scale all at once based on a recent understanding of the spacespace- charge-driven emittance limitation on the ultimate performance of these devices. The projection shows promising parameter space for conducting ultrafast electron micordiffraction at close to single-shot level, which is supported by the latest experimental characterization of such a system.

Using Pilots to Assess the Value and Approach of CMMI Implementation

NASA Technical Reports Server (NTRS)

Godfrey, Sara; Andary, James; Rosenberg, Linda

2002-01-01

At Goddard Space Flight Center (GSFC), we have chosen to use Capability Maturity Model Integrated (CMMI) to guide our process improvement program. Projects at GSFC consist of complex systems of software and hardware that control satellites, operate ground systems, run instruments, manage databases and data and support scientific research. It is a challenge to launch a process improvement program that encompasses our diverse systems, yet is manageable in terms of cost effectiveness. In order to establish the best approach for improvement, our process improvement effort was divided into three phases: 1) Pilot projects; 2) Staged implementation; and 3) Sustainment and continual improvement. During Phase 1 the focus of the activities was on a baselining process, using pre-appraisals in order to get a baseline for making a better cost and effort estimate for the improvement effort. Pilot pre-appraisals were conducted from different perspectives so different approaches for process implementation could be evaluated. Phase 1 also concentrated on establishing an improvement infrastructure and training of the improvement teams. At the time of this paper, three pilot appraisals have been completed. Our initial appraisal was performed in a flight software area, considering the flight software organization as the organization. The second appraisal was done from a project perspective, focusing on systems engineering and acquisition, and using the organization as GSFC. The final appraisal was in a ground support software area, again using GSFC as the organization. This paper will present our initial approach, lessons learned from all three pilots and the changes in our approach based on the lessons learned.

Do you see what I hear? Vantage point preference and visual dominance in a time-space synaesthete.

PubMed

Jarick, Michelle; Stewart, Mark T; Smilek, Daniel; Dixon, Michael J

2013-01-01

Time-space synaesthetes "see" time units organized in a spatial form. While the structure might be invariant for most synaesthetes, the perspective by which some view their calendar is somewhat flexible. One well-studied synaesthete L adopts different viewpoints for months seen vs. heard. Interestingly, L claims to prefer her auditory perspective, even though the month names are represented visually upside down. To verify this, we used a spatial-cueing task that included audiovisual month cues. These cues were either congruent with L's preferred "auditory" viewpoint (auditory-only and auditory + month inverted) or incongruent (upright visual-only and auditory + month upright). Our prediction was that L would show enhanced cueing effects (larger response time difference between valid and invalid targets) following the audiovisual congruent cues since both elicit the "preferred" auditory perspective. Also, when faced with conflicting cues, we predicted L would choose the preferred auditory perspective over the visual perspective. As we expected, L did show enhanced cueing effects following the audiovisual congruent cues that corresponded with her preferred auditory perspective, but that the visual perspective dominated when L was faced with both viewpoints simultaneously. The results are discussed with relation to the reification hypothesis of sequence space synaesthesia (Eagleman, 2009).

Do you see what I hear? Vantage point preference and visual dominance in a time-space synaesthete

PubMed Central

Jarick, Michelle; Stewart, Mark T.; Smilek, Daniel; Dixon, Michael J.

2013-01-01

Time-space synaesthetes “see” time units organized in a spatial form. While the structure might be invariant for most synaesthetes, the perspective by which some view their calendar is somewhat flexible. One well-studied synaesthete L adopts different viewpoints for months seen vs. heard. Interestingly, L claims to prefer her auditory perspective, even though the month names are represented visually upside down. To verify this, we used a spatial-cueing task that included audiovisual month cues. These cues were either congruent with L's preferred “auditory” viewpoint (auditory-only and auditory + month inverted) or incongruent (upright visual-only and auditory + month upright). Our prediction was that L would show enhanced cueing effects (larger response time difference between valid and invalid targets) following the audiovisual congruent cues since both elicit the “preferred” auditory perspective. Also, when faced with conflicting cues, we predicted L would choose the preferred auditory perspective over the visual perspective. As we expected, L did show enhanced cueing effects following the audiovisual congruent cues that corresponded with her preferred auditory perspective, but that the visual perspective dominated when L was faced with both viewpoints simultaneously. The results are discussed with relation to the reification hypothesis of sequence space synaesthesia (Eagleman, 2009). PMID:24137140

Theoretical injections: On the therapeutic aesthetics of medical spaces.

PubMed

Evans, Joshua D; Crooks, Valorie A; Kingsbury, Paul T

2009-09-01

In this paper we present a dialogue about the seemingly innocuous presence of environmental art in hospital settings as a way of furthering critical perspectives on the therapeutic landscapes concept and its application to medical spaces. We explicitly consider the potential utility of two perspectives, Foucaultian and Lacanian readings, for understanding the relationship between environmental art and the hospital waiting room. We use this paper as a vehicle to demonstrate how such theoretical perspectives can enhance critical scholarship on the therapeutic landscape concept, particularly as it is applied to settings such as health clinics and hospitals. A brief agenda for further critical engagements with the therapeutic nature of health care spaces is put forth in the conclusion.

Applications of Space-Time Duality

NASA Astrophysics Data System (ADS)

Plansinis, Brent W.

The concept of space-time duality is based on a mathematical analogy between paraxial diffraction and narrowband dispersion, and has led to the development of temporal imaging systems. The first part of this thesis focuses on the development of a temporal imaging system for the Laboratory for Laser Energetics. Using an electro-optic phase modulator as a time lens, a time-to-frequency converter is constructed capable of imaging pulses between 3 and 12 ps. Numerical simulations show how this system can be improved to image the 1-30 ps range used in OMEGA-EP. By adjusting the timing between the pulse and the sinusoidal clock of the phase modulator, the pulse spectrum can be selectively narrowed, broadened, or shifted. An experimental demonstration of this effect achieved spectral narrowing and broadening by a factor of 2. Numerical simulations show narrowing by a factor of 8 is possible with modern phase modulators. The second part of this thesis explores the space-time analog of reflection and refraction from a moving refractive index boundary. From a physics perspective, a temporal boundary breaks translational symmetry in time, requiring the momentum of the photon to remain unchanged while its energy may change. This leads to a shifting and splitting of the pulse spectrum as the boundary is crossed. Equations for the reflected and transmitted frequencies and a condition for total internal reflection are found. Two of these boundaries form a temporal waveguide, which confines the pulse to a narrow temporal window. These waveguides have a finite number of modes, which do not change during propagation. A single-mode waveguide can be created, allowing only a single pulse shape to form within the waveguide. Temporal reflection and refraction produce a frequency dependent phase shift on the incident pulse, leading to interference fringes between the incident light and the reflected light. In a waveguide, this leads to self-imaging, where the pulse shape reforms periodically at finite propagation lengths. Numerical simulations are performed for the specific case where the moving boundary is produced through cross-phase modulation. In this case, the Kerr nonlinearity causes the boundary to change during propagation, leading to unique temporal and spectral behavior.

The soft embodiment of culture: camera angles and motion through time and space.

PubMed

Leung, Angela K-y; Cohen, Dov

2007-09-01

Cultural assumptions about one's relation to others and one's place in the world can be literally embodied in the way one cognitively maps out one's position and motion in time and space. In three experiments, we examined the psychological perspective that Asian American and Euro-American participants embodied as they both comprehended and produced narratives and mapped out metaphors of time and space. In social situations, Euro-American participants were more likely to embody their own perspective and a sense of their own motion (rather than those of a friend), whereas Asian American participants were more likely to embody a friend's perspective and sense of motion (rather than their own). We discuss how these psychological perspectives represent the soft embodiment of culture by implicitly instantiating cultural injunctions (a) to think about how you look to others and to harmonize with them or (b) to know yourself, trust yourself, and act with confidence.

Phase-space networks of geometrically frustrated systems.

PubMed

Han, Yilong

2009-11-01

We illustrate a network approach to the phase-space study by using two geometrical frustration models: antiferromagnet on triangular lattice and square ice. Their highly degenerated ground states are mapped as discrete networks such that the quantitative network analysis can be applied to phase-space studies. The resulting phase spaces share some comon features and establish a class of complex networks with unique Gaussian spectral densities. Although phase-space networks are heterogeneously connected, the systems are still ergodic due to the random Poisson processes. This network approach can be generalized to phase spaces of some other complex systems.

Geospatial Perspective: Toward a Visual Political Literacy Project in Education, Health, and Human Services

ERIC Educational Resources Information Center

Hogrebe, Mark C.; Tate, William F., IV

2012-01-01

In this chapter, "geospatial" refers to geographic space that includes location, distance, and the relative position of things on the earth's surface. Geospatial perspective calls for the addition of a geographic lens that focuses on place and space as important contextual variables. A geospatial view increases one's understanding of…

Perspectives on energy storage wheels for space station application

NASA Technical Reports Server (NTRS)

Oglevie, R. E.

1984-01-01

Several of the issues of the workshop are addressed from the perspective of a potential Space Station developer and energy wheel user. Systems' considerations are emphasized rather than component technology. The potential of energy storage wheel (ESW) concept is discussed. The current status of the technology base is described. Justification for advanced technology development is also discussed. The study concludes that energy storage in wheels is an attractive concept for immediate technology development and future Space Station application.

Subliminal encoding and flexible retrieval of objects in scenes.

PubMed

Wuethrich, Sergej; Hannula, Deborah E; Mast, Fred W; Henke, Katharina

2018-04-27

Our episodic memory stores what happened when and where in life. Episodic memory requires the rapid formation and flexible retrieval of where things are located in space. Consciousness of the encoding scene is considered crucial for episodic memory formation. Here, we question the necessity of consciousness and hypothesize that humans can form unconscious episodic memories. Participants were presented with subliminal scenes, i.e., scenes invisible to the conscious mind. The scenes displayed objects at certain locations for participants to form unconscious object-in-space memories. Later, the same scenes were presented supraliminally, i.e., visibly, for retrieval testing. Scenes were presented absent the objects and rotated by 90°-270° in perspective to assess the representational flexibility of unconsciously formed memories. During the test phase, participants performed a forced-choice task that required them to place an object in one of two highlighted scene locations and their eye movements were recorded. Evaluation of the eye tracking data revealed that participants remembered object locations unconsciously, irrespective of changes in viewing perspective. This effect of gaze was related to correct placements of objects in scenes, and an intuitive decision style was necessary for unconscious memories to influence intentional behavior to a significant degree. We conclude that conscious perception is not mandatory for spatial episodic memory formation. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

Illustration of microphysical processes in Amazonian deep convective clouds in the gamma phase space: introduction and potential applications

NASA Astrophysics Data System (ADS)

Cecchini, Micael A.; Machado, Luiz A. T.; Wendisch, Manfred; Costa, Anja; Krämer, Martina; Andreae, Meinrat O.; Afchine, Armin; Albrecht, Rachel I.; Artaxo, Paulo; Borrmann, Stephan; Fütterer, Daniel; Klimach, Thomas; Mahnke, Christoph; Martin, Scot T.; Minikin, Andreas; Molleker, Sergej; Pardo, Lianet H.; Pöhlker, Christopher; Pöhlker, Mira L.; Pöschl, Ulrich; Rosenfeld, Daniel; Weinzierl, Bernadett

2017-12-01

The behavior of tropical clouds remains a major open scientific question, resulting in poor representation by models. One challenge is to realistically reproduce cloud droplet size distributions (DSDs) and their evolution over time and space. Many applications, not limited to models, use the gamma function to represent DSDs. However, even though the statistical characteristics of the gamma parameters have been widely studied, there is almost no study dedicated to understanding the phase space of this function and the associated physics. This phase space can be defined by the three parameters that define the DSD intercept, shape, and curvature. Gamma phase space may provide a common framework for parameterizations and intercomparisons. Here, we introduce the phase space approach and its characteristics, focusing on warm-phase microphysical cloud properties and the transition to the mixed-phase layer. We show that trajectories in this phase space can represent DSD evolution and can be related to growth processes. Condensational and collisional growth may be interpreted as pseudo-forces that induce displacements in opposite directions within the phase space. The actually observed movements in the phase space are a result of the combination of such pseudo-forces. Additionally, aerosol effects can be evaluated given their significant impact on DSDs. The DSDs associated with liquid droplets that favor cloud glaciation can be delimited in the phase space, which can help models to adequately predict the transition to the mixed phase. We also consider possible ways to constrain the DSD in two-moment bulk microphysics schemes, in which the relative dispersion parameter of the DSD can play a significant role. Overall, the gamma phase space approach can be an invaluable tool for studying cloud microphysical evolution and can be readily applied in many scenarios that rely on gamma DSDs.

Microbial Monitoring of Crewed Habitats in Space—Current Status and Future Perspectives

PubMed Central

Yamaguchi, Nobuyasu; Roberts, Michael; Castro, Sarah; Oubre, Cherie; Makimura, Koichi; Leys, Natalie; Grohmann, Elisabeth; Sugita, Takashi; Ichijo, Tomoaki; Nasu, Masao

2014-01-01

Previous space research conducted during short-term flight experiments and long-term environmental monitoring on board orbiting space stations suggests that the relationship between humans and microbes is altered in the crewed habitat in space. Both human physiology and microbial communities adapt to spaceflight. Microbial monitoring is critical to crew safety in long-duration space habitation and the sustained operation of life support systems on space transit vehicles, space stations, and surface habitats. To address this critical need, space agencies including NASA (National Aeronautics and Space Administration), ESA (European Space Agency), and JAXA (Japan Aerospace Exploration Agency) are working together to develop and implement specific measures to monitor, control, and counteract biological contamination in closed-environment systems. In this review, the current status of microbial monitoring conducted in the International Space Station (ISS) as well as the results of recent microbial spaceflight experiments have been summarized and future perspectives are discussed. PMID:25130885

Psychometric Analysis of the Life Perspectives Inventory and Implications for Assessing Characteristics of Adolescent Spirituality

ERIC Educational Resources Information Center

Sink, Christopher A.; Bultsma, Shawn A.

2014-01-01

The psychometric properties of the Life Perspectives Inventory (LPI-English language version), a new instrument designed to assess characteristics associated with nonreligious spirituality in high school-age adolescents, were examined in two phases. Phase 1 demonstrated the survey's factorial validity and internal consistency and the test-retest…

The Power of Poincaré: Elucidating the Hidden Symmetries in Focal Conic Domains

NASA Astrophysics Data System (ADS)

Matsumoto, Elisabetta A.; Alexander, Gareth P.; Chen, Bryan Gin-Ge; Kamien, Randall D.

2011-03-01

Focal conic domains are typically the ``smoking gun'' by which smectic liquid crystalline phases are identified. The geometry of the equally spaced smectic layers is highly generic but, at the same time, difficult to work with. We develop an approach to the study of focal sets in smectics which exploits a hidden Poincaré symmetry revealed only by viewing the smectic layers as projections from one-higher dimension. We use this perspective to shed light upon the concentric cyclides of Dupin and several classic focal conic textures which exhibit a more widespread level of geometric organization as in Friedel's law of corresponding cones, the networks and trellises expounded by Bouligand, or Apollonian packings.

Phase Space Exchange in Thick Wedge Absorbers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neuffer, David

The problem of phase space exchange in wedge absorbers with ionization cooling is discussed. The wedge absorber exchanges transverse and longitudinal phase space by introducing a position-dependent energy loss. In this paper we note that the wedges used with ionization cooling are relatively thick, so that single wedges cause relatively large changes in beam phase space. Calculation methods adapted to such “thick wedge” cases are presented, and beam phase-space transformations through such wedges are discussed.

Identity as "knowing your place": the narrative construction of space in a healthcare profession.

PubMed

van Vuuren, Mark; Westerhof, Gerben J

2015-03-01

The construction of space in which a story takes place can have important consequences for the evaluation of health interventions. In this article, we explore the ways professionals narratively position themselves in a situation, treating identity literally as "knowing one's place." More specifically, we explore the spatial language health professionals use to describe their work. Using descriptions of professionals in a drug habilitation organization, we illustrate how they use route (i.e., an active tour through the space), survey (i.e., a stationary viewpoint from above), and gaze perspectives (i.e. a stable viewpoint onto a place) to explain the work situations they encounter. Each of these perspectives facilitates a different mode of evaluation in terms of distance, emotion, and identity. We propose opportunities for research and implications of the ways in which spaces and spatial perspectives set the scene in the narratives of healthcare professionals. © The Author(s) 2015.

Phase-space topography characterization of nonlinear ultrasound waveforms.

PubMed

Dehghan-Niri, Ehsan; Al-Beer, Helem

2018-03-01

Fundamental understanding of ultrasound interaction with material discontinuities having closed interfaces has many engineering applications such as nondestructive evaluation of defects like kissing bonds and cracks in critical structural and mechanical components. In this paper, to analyze the acoustic field nonlinearities due to defects with closed interfaces, the use of a common technique in nonlinear physics, based on a phase-space topography construction of ultrasound waveform, is proposed. The central idea is to complement the "time" and "frequency" domain analyses with the "phase-space" domain analysis of nonlinear ultrasound waveforms. A nonlinear time series method known as pseudo phase-space topography construction is used to construct equivalent phase-space portrait of measured ultrasound waveforms. Several nonlinear models are considered to numerically simulate nonlinear ultrasound waveforms. The phase-space response of the simulated waveforms is shown to provide different topographic information, while the frequency domain shows similar spectral behavior. Thus, model classification can be substantially enhanced in the phase-space domain. Experimental results on high strength aluminum samples show that the phase-space transformation provides a unique detection and classification capabilities. The Poincaré map of the phase-space domain is also used to better understand the nonlinear behavior of ultrasound waveforms. It is shown that the analysis of ultrasound nonlinearities is more convenient and informative in the phase-space domain than in the frequency domain. Copyright © 2017 Elsevier B.V. All rights reserved.

Gymnastics in Phase Space

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chao, Alexander Wu; /SLAC

2012-03-01

As accelerator technology advances, the requirements on accelerator beam quality become increasingly demanding. Facing these new demands, the topic of phase space gymnastics is becoming a new focus of accelerator physics R&D. In a phase space gymnastics, the beam's phase space distribution is manipulated and precision tailored to meet the required beam qualities. On the other hand, all realization of such gymnastics will have to obey accelerator physics principles as well as technological limitations. Recent examples of phase space gymnastics include Emittance exchanges, Phase space exchanges, Emittance partitioning, Seeded FELs and Microbunched beams. The emittance related topics of this listmore » are reviewed in this report. The accelerator physics basis, the optics design principles that provide these phase space manipulations, and the possible applications of these gymnastics, are discussed. This fascinating new field promises to be a powerful tool of the future.« less

An Embodiment Perspective on Number-Space Mapping in 3.5-year-old Dutch Children

ERIC Educational Resources Information Center

Noordende, Jaccoline E.; Volman, M(Chiel). J. M.; Leseman, Paul P. M.; Kroesbergen, Evelyn H.

2017-01-01

Previous research suggests that block adding, subtracting and counting direction are early forms of number-space mapping. In this study, an embodiment perspective on these skills was taken. Embodiment theory assumes that cognition emerges through sensory-motor interaction with the environment. In line with this assumption, it was investigated if…

High Energy Scattering in the AdS/CFT Correspondence

NASA Astrophysics Data System (ADS)

Penedones, Joao

2007-12-01

This work explores the celebrated AdS/CFT correspondence in the regime of high energy scattering in Anti--de Sitter (AdS) spacetime. In particular, we develop the eikonal approximation to high energy scattering in AdS and explore its consequences for the dual Conformal Field Theory (CFT). Using position space Feynman rules, we rederive the eikonal approximation for high energy scattering in flat space. Following this intuitive position space perspective, we then generalize the eikonal approximation for high energy scattering in AdS and other spacetimes. Remarkably, we are able to resum, in terms of a generalized phase shift, ladder and cross ladder Witten diagrams associated to the exchange of an AdS spin j field, to all orders in the coupling constant. By the AdS/CFT correspondence, the eikonal amplitude in AdS is related to the four point function of CFT primary operators in the regime of large 't Hooft coupling, including all terms of the 1/N expansion. We then show that the eikonal amplitude determines the behavior of the CFT four point function for small values of the cross ratios in a Lorentzian regime and that this controls its high spin and dimension conformal partial wave decomposition. These results allow us to determine the anomalous dimension of high spin and dimension double trace primary operators, by relating it to the AdS eikonal phase shift. Finally we find that, at large energies and large impact parameters in AdS, the gravitational interaction dominates all other interactions, as in flat space. Therefore, the anomalous dimension of double trace operators, associated to graviton exchange in AdS, yields a universal prediction for CFT's with AdS gravitational duals.

The Development of Teacher Perspectives: Final Report.

ERIC Educational Resources Information Center

Tabachnick, B. Robert; Zeichner, Kenneth M.

This longitudinal study of the development of perspectives toward teaching consists of three major phases: (1) an examination of the impact of the student teaching experience on the development of teacher perspectives; (2) an examination of the continuing development of teacher perspectives during the first year of teaching; and (3) further…

Phase-space evolution of x-ray coherence in phase-sensitive imaging.

PubMed

Wu, Xizeng; Liu, Hong

2008-08-01

X-ray coherence evolution in the imaging process plays a key role for x-ray phase-sensitive imaging. In this work we present a phase-space formulation for the phase-sensitive imaging. The theory is reformulated in terms of the cross-spectral density and associated Wigner distribution. The phase-space formulation enables an explicit and quantitative account of partial coherence effects on phase-sensitive imaging. The presented formulas for x-ray spectral density at the detector can be used for performing accurate phase retrieval and optimizing the phase-contrast visibility. The concept of phase-space shearing length derived from this phase-space formulation clarifies the spatial coherence requirement for phase-sensitive imaging with incoherent sources. The theory has been applied to x-ray Talbot interferometric imaging as well. The peak coherence condition derived reveals new insights into three-grating-based Talbot-interferometric imaging and gratings-based x-ray dark-field imaging.

Transformations and representations supporting spatial perspective taking

PubMed Central

Yu, Alfred B.; Zacks, Jeffrey M.

2018-01-01

Spatial perspective taking is the ability to reason about spatial relations relative to another’s viewpoint. Here, we propose a mechanistic hypothesis that relates mental representations of one’s viewpoint to the transformations used for spatial perspective taking. We test this hypothesis using a novel behavioral paradigm that assays patterns of response time and variation in those patterns across people. The results support the hypothesis that people maintain a schematic representation of the space around their body, update that representation to take another’s perspective, and thereby to reason about the space around their body. This is a powerful computational mechanism that can support imitation, coordination of behavior, and observational learning. PMID:29545731

Role of CFD in propulsion design - Government perspective

NASA Technical Reports Server (NTRS)

Schutzenhofer, L. A.; Mcconnaughey, H. V.; Mcconnaughey, P. K.

1990-01-01

Various aspects of computational fluid dynamics (CFD), as it relates to design applications in rocket propulsion activities from the government perspective, are discussed. Specific examples are given that demonstrate the application of CFD to support hardware development activities, such as Space Shuttle Main Engine flight issues, and the associated teaming strategy used for solving such problems. In addition, select examples that delineate the motivation, methods of approach, goals and key milestones for several space flight progams are cited. An approach is described toward applying CFD in the design environment from the government perspective. A discussion of benchmark validation, advanced technology hardware concepts, accomplishments, needs, future applications, and near-term expectations from the flight-center perspective is presented.

Philosophical and Psychopathological Perspective of Exile: On Time and Space Experiences

PubMed Central

Silva Rojas, Matías; Armijo Nuñez, Julio; Nuñez Erices, Gonzalo

2015-01-01

This article addresses the experience of exile from an interdisciplinary perspective (philosophy and psychiatry). The main purpose is to try to understand the experience of exile by rehearsing a psychopathological perspective to address it, so it can help with the treatment of disorders that come with this experience. Furthermore, the article tries to explore the experience and reflection of philosophers and thinkers who, being exiled themselves, tried to understand and explain this radical human experience, focusing on the experience of time and space. PMID:26074825

Phase Transitions in Development of Writing Fluency from a Complex Dynamic Systems Perspective

ERIC Educational Resources Information Center

Baba, Kyoko; Nitta, Ryo

2014-01-01

This study explored patterns in L2 writing development by focusing on one of the linguistic features of texts (fluency) from a complex dynamic systems perspective. It investigated whether two English-as-a-foreign-language university students would experience discontinuous change (phase transition) in their writing fluency through repetition of a…

SLS Core Stage Simulator

NASA Image and Video Library

2015-02-02

CHRISTOPHER CRUMBLY, MANAGER OF THE SPACECRAFT PAYLOAD INTEGRATION AND EVOLUTION OFFICE, GAVE VISITORS AN INSIDER'S PERSPECTIVE ON THE CORE STAGE SIMULATOR AT MARSHALL AND ITS IMPORTANCE TO DEVELOPMENT OF THE SPACE LAUNCH SYSTEM. CHRISTOPHER CRUMBLY, MANAGER OF THE SPACECRAFT PAYLOAD INTEGRATION AND EVOLUTION OFFICE, GAVE VISITORS AN INSIDER'S PERSPECTIVE ON THE CORE STAGE SIMULATOR AT MARSHALL AND ITS IMPORTANCE TO DEVELOPMENT OF THE SPACE LAUNCH SYSTEM.

Tightly Coupled Mechanistic Study of Materials in the Extreme Space Environment

DTIC Science & Technology

2016-10-11

to examine spacecraft contamination issues from the perspective of non- equilibrium gas dynamics (Levin), material response at the atomistic level...Space Environment Group has worked to examine spacecraft contamination issues from the perspective of non- equilibrium gas dynamics (Levin...material response at the atomistic level (Rajan), high fidelity gas -surface chemistry models (van Duin), and experiments to characterize and test

A general formalism for phase space calculations

NASA Technical Reports Server (NTRS)

Norbury, John W.; Deutchman, Philip A.; Townsend, Lawrence W.; Cucinotta, Francis A.

1988-01-01

General formulas for calculating the interactions of galactic cosmic rays with target nuclei are presented. Methods for calculating the appropriate normalization volume elements and phase space factors are presented. Particular emphasis is placed on obtaining correct phase space factors for 2-, and 3-body final states. Calculations for both Lorentz-invariant and noninvariant phase space are presented.

Scanning Synchronization of Colliding Bunches for MEIC Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Derbenev, Yaroslav S.; Popov, V. P.; Chernousov, Yu D.

2015-09-01

Synchronization of colliding beams is one of the major issues of an electron-ion collider (EIC) design because of sensitivity of ion revolution frequency to beam energy. A conventional solution for this trouble is insertion of bent chicanes in the arcs space. In our report we consider a method to provide space coincidence of encountering bunches in the crab-crossing orbits Interaction Region (IR) while repetition rates of two beams do not coincide. The method utilizes pair of fast kickers realizing a bypass for the electron bunches as the way to equalize positions of the colliding bunches at the Interaction Point (IP).more » A dipole-mode warm or SRF cavities fed by the magnetron transmitters are used as fast kickers, allowing a broad-band phase and amplitude control. The proposed scanning synchronization method implies stabilization of luminosity at a maximum via a feedback loop. This synchronization method is evaluated as perspective for the Medium Energy Electron-Ion collider (MEIC) project of JLab with its very high bunch repetition rate.« less

Nonequilibrium life-cycles in Ocean Heat Content

NASA Astrophysics Data System (ADS)

Weiss, Jeffrey B.; Fox-Kemper, Baylor; Mandal, Dibyendu; Zia, Royce K. P.

2014-03-01

Natural climate variability can be considered as fluctuations in a nonequilibrium steady state. A fundamental property of nonequilibrium steady states is the phase space current which provides a preferred direction for fluctuations, and is manifested as preferred life-cycles for climate fluctuations. We propose a new quantity, the phase space angular momentum, to quantify the phase space rotation. In analogy with traditional angular momentum, which quantifies the rotation of mass in physical space, the phase space angular momentum quantifies the rotation of probability in phase space. It has the additional advantage that it is straightforward to calculate from a time series. We investigate the phase space angular momentum for fluctuations in ocean heat content in both observations and ocean general circulation models. We gratefully acknowledge financial support from the National Science Foundation (USA) under grant OCE 1245944.

Quantum mechanics on phase space: The hydrogen atom and its Wigner functions

NASA Astrophysics Data System (ADS)

Campos, P.; Martins, M. G. R.; Fernandes, M. C. B.; Vianna, J. D. M.

2018-03-01

Symplectic quantum mechanics (SQM) considers a non-commutative algebra of functions on a phase space Γ and an associated Hilbert space HΓ, to construct a unitary representation for the Galilei group. From this unitary representation the Schrödinger equation is rewritten in phase space variables and the Wigner function can be derived without the use of the Liouville-von Neumann equation. In this article the Coulomb potential in three dimensions (3D) is resolved completely by using the phase space Schrödinger equation. The Kustaanheimo-Stiefel(KS) transformation is applied and the Coulomb and harmonic oscillator potentials are connected. In this context we determine the energy levels, the amplitude of probability in phase space and correspondent Wigner quasi-distribution functions of the 3D-hydrogen atom described by Schrödinger equation in phase space.

Space station MSFC-DPD-235/DR no. MA-05 phase C/D program development plan. Volume 2: Phase C/D, programmatic requirements

NASA Technical Reports Server (NTRS)

1971-01-01

The design plan requirements define the design implementation and control requirements for Phase C/D of the Modular Space Station Project and specifically address the Initial Space Station phase of the Space Station Program (modular). It is based primarily on the specific objective of translating the requirements of the Space Station Program, Project, Interface, and Support Requirements and preliminary contract end x item specifications into detail design of the operational systems which comprise the initial space station. This document is designed to guide aerospace contractors in the planning and bidding for Phase C/D.

Fundamental Principles of Proper Space Kinematics

NASA Astrophysics Data System (ADS)

Wade, Sean

It is desirable to understand the movement of both matter and energy in the universe based upon fundamental principles of space and time. Time dilation and length contraction are features of Special Relativity derived from the observed constancy of the speed of light. Quantum Mechanics asserts that motion in the universe is probabilistic and not deterministic. While the practicality of these dissimilar theories is well established through widespread application inconsistencies in their marriage persist, marring their utility, and preventing their full expression. After identifying an error in perspective the current theories are tested by modifying logical assumptions to eliminate paradoxical contradictions. Analysis of simultaneous frames of reference leads to a new formulation of space and time that predicts the motion of both kinds of particles. Proper Space is a real, three-dimensional space clocked by proper time that is undergoing a densification at the rate of c. Coordinate transformations to a familiar object space and a mathematical stationary space clarify the counterintuitive aspects of Special Relativity. These symmetries demonstrate that within the local universe stationary observers are a forbidden frame of reference; all is in motion. In lieu of Quantum Mechanics and Uncertainty the use of the imaginary number i is restricted for application to the labeling of mass as either material or immaterial. This material phase difference accounts for both the perceived constant velocity of light and its apparent statistical nature. The application of Proper Space Kinematics will advance more accurate representations of microscopic, oscopic, and cosmological processes and serve as a foundation for further study and reflection thereafter leading to greater insight.

Geographical impacts on social networks from perspectives of space and place: an empirical study using mobile phone data

NASA Astrophysics Data System (ADS)

Shi, Li; Wu, Lun; Chi, Guanghua; Liu, Yu

2016-10-01

Space and place are two fundamental concepts in geography. Geographical factors have long been known as drivers of many aspects of people's social networks. But whether and how space and place affect social networks differently are still unclear. The widespread use of location-aware devices provides a novel source for distinguishing the mechanisms of their impacts on social networks. Using mobile phone data, this paper explores the effects of space and place on social networks. From the perspective of space, we confirm the distance decay effect in social networks, based on a comparison between synthetic social ties generated by a null model and actual social ties derived from real-world data. From the perspective of place, we introduce several measures to evaluate interactions between individuals and inspect the trio relationship including distance, spatio-temporal co-occurrence, and social ties. We found that people's interaction is a more important factor than spatial proximity, indicating that the spatial factor has a stronger impact on social networks in place compared to that in space. Furthermore, we verify the hypothesis that interactions play an important role in strengthening friendships.

Transportation and platforms perspective

NASA Technical Reports Server (NTRS)

Bennett, Gary L.

1992-01-01

The topics covered are presented in viewgraph form and include the following: Office of Aeronautics and Space Technology; space research and technology (R&T); space R&T mission statement; Space R&T program development; R&T strategy; Office of Space Science and Applications (OSSA) technology needs; transportation technology; and space platforms technology.

Computational Methods to Assess the Production Potential of Bio-Based Chemicals.

PubMed

Campodonico, Miguel A; Sukumara, Sumesh; Feist, Adam M; Herrgård, Markus J

2018-01-01

Elevated costs and long implementation times of bio-based processes for producing chemicals represent a bottleneck for moving to a bio-based economy. A prospective analysis able to elucidate economically and technically feasible product targets at early research phases is mandatory. Computational tools can be implemented to explore the biological and technical spectrum of feasibility, while constraining the operational space for desired chemicals. In this chapter, two different computational tools for assessing potential for bio-based production of chemicals from different perspectives are described in detail. The first tool is GEM-Path: an algorithm to compute all structurally possible pathways from one target molecule to the host metabolome. The second tool is a framework for Modeling Sustainable Industrial Chemicals production (MuSIC), which integrates modeling approaches for cellular metabolism, bioreactor design, upstream/downstream processes, and economic impact assessment. Integrating GEM-Path and MuSIC will play a vital role in supporting early phases of research efforts and guide the policy makers with decisions, as we progress toward planning a sustainable chemical industry.

Scanning the horizon for high value-add manufacturing science: Accelerating manufacturing readiness for the next generation of disruptive, high-value curative cell therapeutics.

PubMed

Hourd, Paul; Williams, David J

2018-05-01

Since the regenerative medicine sector entered the second phase of its development (RegenMed 2.0) more than a decade ago, there is increasing recognition that current technology innovation trajectories will drive the next translational phase toward the production of disruptive, high-value curative cell and gene-based regenerative medicines. To identify the manufacturing science problems that must be addressed to permit translation of these next generation therapeutics. In this short report, a long lens look within the pluripotent stem cell therapeutic space, both embryonic and induced, is used to gain early insights on where critical technology and manufacturing challenges may emerge. This report offers a future perspective on the development and innovation that will be needed within manufacturing science to add value in the production and commercialization of the next generation of advanced cell therapies and precision medicines. Copyright © 2018 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Space: The High Frontier in Perspective. Worldwatch Paper 50.

ERIC Educational Resources Information Center

Deudney, Daniel

This paper examines how the exploration of space has affected life on earth. Examined are milestones in space, war or peace in space, learning about earth from space, the satellite communications revolution, space industrialization, and the ownership of space. The real beginning of the Space Age was the October 1957 Soviet launch of a 184-pound…

Beyond the continuum: a multi-dimensional phase space for neutral-niche community assembly.

PubMed

Latombe, Guillaume; Hui, Cang; McGeoch, Melodie A

2015-12-22

Neutral and niche processes are generally considered to interact in natural communities along a continuum, exhibiting community patterns bounded by pure neutral and pure niche processes. The continuum concept uses niche separation, an attribute of the community, to test the hypothesis that communities are bounded by pure niche or pure neutral conditions. It does not accommodate interactions via feedback between processes and the environment. By contrast, we introduce the Community Assembly Phase Space (CAPS), a multi-dimensional space that uses community processes (such as dispersal and niche selection) to define the limiting neutral and niche conditions and to test the continuum hypothesis. We compare the outputs of modelled communities in a heterogeneous landscape, assembled by pure neutral, pure niche and composite processes. Differences in patterns under different combinations of processes in CAPS reveal hidden complexity in neutral-niche community dynamics. The neutral-niche continuum only holds for strong dispersal limitation and niche separation. For weaker dispersal limitation and niche separation, neutral and niche processes amplify each other via feedback with the environment. This generates patterns that lie well beyond those predicted by a continuum. Inferences drawn from patterns about community assembly processes can therefore be misguided when based on the continuum perspective. CAPS also demonstrates the complementary information value of different patterns for inferring community processes and captures the complexity of community assembly. It provides a general tool for studying the processes structuring communities and can be applied to address a range of questions in community and metacommunity ecology. © 2015 The Author(s).

Beyond the continuum: a multi-dimensional phase space for neutral–niche community assembly

PubMed Central

Latombe, Guillaume; McGeoch, Melodie A.

2015-01-01

Neutral and niche processes are generally considered to interact in natural communities along a continuum, exhibiting community patterns bounded by pure neutral and pure niche processes. The continuum concept uses niche separation, an attribute of the community, to test the hypothesis that communities are bounded by pure niche or pure neutral conditions. It does not accommodate interactions via feedback between processes and the environment. By contrast, we introduce the Community Assembly Phase Space (CAPS), a multi-dimensional space that uses community processes (such as dispersal and niche selection) to define the limiting neutral and niche conditions and to test the continuum hypothesis. We compare the outputs of modelled communities in a heterogeneous landscape, assembled by pure neutral, pure niche and composite processes. Differences in patterns under different combinations of processes in CAPS reveal hidden complexity in neutral–niche community dynamics. The neutral–niche continuum only holds for strong dispersal limitation and niche separation. For weaker dispersal limitation and niche separation, neutral and niche processes amplify each other via feedback with the environment. This generates patterns that lie well beyond those predicted by a continuum. Inferences drawn from patterns about community assembly processes can therefore be misguided when based on the continuum perspective. CAPS also demonstrates the complementary information value of different patterns for inferring community processes and captures the complexity of community assembly. It provides a general tool for studying the processes structuring communities and can be applied to address a range of questions in community and metacommunity ecology. PMID:26702047

Space Flight: The First 30 Years

NASA Technical Reports Server (NTRS)

1991-01-01

A history of space flight from Project Mercury to the Space Shuttle is told from the perspective of NASA flight programs. Details are given on Mercury missions, Gemini missions, Apollo missions, Skylab missions, the Apollo-Soyuz Test Project, and the Space Shuttle missions.

[Development of nursing key performance indicators for an intensive care unit by using a balanced scorecard].

PubMed

Choi, Yun Jeong; Lim, Ji Young; Lee, Young Whee; Kim, Hwa Soon

2008-10-01

The purpose of this study was to develop visions of nursing service, nursing strategies and key performance indicators (KPIs) for an intensive care unit (ICU) based on a Balanced Scorecard (BSC). This study was undertaken by using methodological research. The development process consisted of four phases; the first phase was to develop the vision of nursing in ICUs. The second phase was to develop strategies according to 4 perspectives of a BSC. The third phase was to develop KPIs according to the 4 perspectives of BSC and the final phase was to combine the nursing visions, strategies and KPIs of ICUs. Two main visions of nursing service for ICUs were established. These were 'realization of harmonized professional nursing with human respect' and 'recovery of health through specialized nursing' respectively. In order to reach the aim of developing nursing visions, thirteen practical strategies and nineteen KPIs were developed by four perspectives of the BSC. The results will be used as objective fundamental data to attain business outcomes for the achievement of nursing visions and strategies of ICUs.

TU-AB-BRC-07: Efficiency of An IAEA Phase-Space Source for a Low Energy X-Ray Tube Using Egs++

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watson, PGF; Renaud, MA; Seuntjens, J

Purpose: To extend the capability of the EGSnrc C++ class library (egs++) to write and read IAEA phase-space files as a particle source, and to assess the relative efficiency gain in dose calculation using an IAEA phase-space source for modelling a miniature low energy x-ray source. Methods: We created a new ausgab object to score particles exiting a user-defined geometry and write them to an IAEA phase-space file. A new particle source was created to read from IAEA phase-space data. With these tools, a phase-space file was generated for particles exiting a miniature 50 kVp x-ray tube (The INTRABEAM System,more » Carl Zeiss). The phase-space source was validated by comparing calculated PDDs with a full electron source simulation of the INTRABEAM. The dose calculation efficiency gain of the phase-space source was determined relative to the full simulation. The efficiency gain as a function of i) depth in water, and ii) job parallelization was investigated. Results: The phase-space and electron source PDDs were found to agree to 0.5% RMS, comparable to statistical uncertainties. The use of a phase-space source for the INTRABEAM led to a relative efficiency gain of greater than 20 over the full electron source simulation, with an increase of up to a factor of 196. The efficiency gain was found to decrease with depth in water, due to the influence of scattering. Job parallelization (across 2 to 256 cores) was not found to have any detrimental effect on efficiency gain. Conclusion: A set of tools has been developed for writing and reading IAEA phase-space files, which can be used with any egs++ user code. For simulation of a low energy x-ray tube, the use of a phase-space source was found to increase the relative dose calculation efficiency by factor of up to 196. The authors acknowledge partial support by the CREATE Medical Physics Research Training Network grant of the Natural Sciences and Engineering Research Council (Grant No. 432290).« less

Referential shift in Nicaraguan Sign Language: a transition from lexical to spatial devices

PubMed Central

Kocab, Annemarie; Pyers, Jennie; Senghas, Ann

2015-01-01

Even the simplest narratives combine multiple strands of information, integrating different characters and their actions by expressing multiple perspectives of events. We examined the emergence of referential shift devices, which indicate changes among these perspectives, in Nicaraguan Sign Language (NSL). Sign languages, like spoken languages, mark referential shift grammatically with a shift in deictic perspective. In addition, sign languages can mark the shift with a point or a movement of the body to a specified spatial location in the three-dimensional space in front of the signer, capitalizing on the spatial affordances of the manual modality. We asked whether the use of space to mark referential shift emerges early in a new sign language by comparing the first two age cohorts of deaf signers of NSL. Eight first-cohort signers and 10 second-cohort signers watched video vignettes and described them in NSL. Narratives were coded for lexical (use of words) and spatial (use of signing space) devices. Although the cohorts did not differ significantly in the number of perspectives represented, second-cohort signers used referential shift devices to explicitly mark a shift in perspective in more of their narratives. Furthermore, while there was no significant difference between cohorts in the use of non-spatial, lexical devices, there was a difference in spatial devices, with second-cohort signers using them in significantly more of their narratives. This suggests that spatial devices have only recently increased as systematic markers of referential shift. Spatial referential shift devices may have emerged more slowly because they depend on the establishment of fundamental spatial conventions in the language. While the modality of sign languages can ultimately engender the syntactic use of three-dimensional space, we propose that a language must first develop systematic spatial distinctions before harnessing space for grammatical functions. PMID:25713541

Referential shift in Nicaraguan Sign Language: a transition from lexical to spatial devices.

PubMed

Kocab, Annemarie; Pyers, Jennie; Senghas, Ann

2014-01-01

Even the simplest narratives combine multiple strands of information, integrating different characters and their actions by expressing multiple perspectives of events. We examined the emergence of referential shift devices, which indicate changes among these perspectives, in Nicaraguan Sign Language (NSL). Sign languages, like spoken languages, mark referential shift grammatically with a shift in deictic perspective. In addition, sign languages can mark the shift with a point or a movement of the body to a specified spatial location in the three-dimensional space in front of the signer, capitalizing on the spatial affordances of the manual modality. We asked whether the use of space to mark referential shift emerges early in a new sign language by comparing the first two age cohorts of deaf signers of NSL. Eight first-cohort signers and 10 second-cohort signers watched video vignettes and described them in NSL. Narratives were coded for lexical (use of words) and spatial (use of signing space) devices. Although the cohorts did not differ significantly in the number of perspectives represented, second-cohort signers used referential shift devices to explicitly mark a shift in perspective in more of their narratives. Furthermore, while there was no significant difference between cohorts in the use of non-spatial, lexical devices, there was a difference in spatial devices, with second-cohort signers using them in significantly more of their narratives. This suggests that spatial devices have only recently increased as systematic markers of referential shift. Spatial referential shift devices may have emerged more slowly because they depend on the establishment of fundamental spatial conventions in the language. While the modality of sign languages can ultimately engender the syntactic use of three-dimensional space, we propose that a language must first develop systematic spatial distinctions before harnessing space for grammatical functions.

Formations Near the Libration Points: Design Strategies Using Natural and Non-Natural Arcs

NASA Technical Reports Server (NTRS)

Howell, K. C.; Marchand, B. G.

2004-01-01

Space based observatory and interferometry missions, such as Terrestrial Planet Finder (TPF), Stellar Imager, and MAXIM, have sparked great interest in multi-spacecraft formation flight in the vicinity of the Sun-Earth/Moon (SEM) libration points. The initial phase of this research considered the formation keeping problem from the perspective of continuous control as applied to non-natural formations. In the present study, closer inspection of the flow, corresponding to the stable and center manifolds near the reference orbit, reveals some interesting natural relative motions as well as some discrete control strategies for deployment. A hybrid control strategy is also employed that combines both the natural formation dynamics with non-natural motions via input feedback linearization techniques.

Hierarchical relaxation dynamics in a tilted two-band Bose-Hubbard model

NASA Astrophysics Data System (ADS)

Cosme, Jayson G.

2018-04-01

We numerically examine slow and hierarchical relaxation dynamics of interacting bosons described by a tilted two-band Bose-Hubbard model. The system is found to exhibit signatures of quantum chaos within the spectrum and the validity of the eigenstate thermalization hypothesis for relevant physical observables is demonstrated for certain parameter regimes. Using the truncated Wigner representation in the semiclassical limit of the system, dynamics of relevant observables reveal hierarchical relaxation and the appearance of prethermalized states is studied from the perspective of statistics of the underlying mean-field trajectories. The observed prethermalization scenario can be attributed to different stages of glassy dynamics in the mode-time configuration space due to dynamical phase transition between ergodic and nonergodic trajectories.

Hierarchical versus degenerate 2HDM: The LHC run 1 legacy at the onset of run 2

NASA Astrophysics Data System (ADS)

Dorsch, G. C.; Huber, S. J.; Mimasu, K.; No, J. M.

2016-06-01

Current discussions of the allowed two-Higgs-doublet model parameter space after LHC run 1 and the prospects for run 2 are commonly phrased in the context of a quasidegenerate spectrum for the new scalars. Here, we discuss the generic situation of a two-Higgs-doublet model with a nondegenerate spectrum for the new scalars. This is highly motivated from a cosmological perspective since it naturally leads to a strongly first-order electroweak phase transition that could explain the matter-antimatter asymmetry in the Universe. While constraints from measurements of Higgs signal strengths do not change, those from searches of new scalar states get modified dramatically once a nondegenerate spectrum is considered.

Effect of friction stir welding parameters on defect formation

NASA Astrophysics Data System (ADS)

Tarasov, S. Yu.; Rubtsov, V. E.; Eliseev, A. A.; Kolubaev, E. A.; Filippov, A. V.; Ivanov, A. N.

2015-10-01

Friction stir welding is a perspective method for manufacturing automotive parts, aviation and space technology. One of the major problems is the formation of welding defects and weld around the welding zone. The formation of defect is the main reason failure of the joint. A possible way to obtain defect-free welded joints is the selection of the correct welding parameters. Experimental results describing the effect of friction stir welding process parameters on the defects of welded joints on aluminum alloy AMg5M have been shown. The weld joint defects have been characterized using the non-destructive radioscopic and ultrasound phase array methods. It was shown how the type and size of defects determine the welded joint strength.

CNO and pep solar neutrino measurements and perspectives in Borexino

NASA Astrophysics Data System (ADS)

Davini, S.; Agostini, M.; Appel, S.; Bellini, G.; Benziger, J.; Bick, D.; Bonfini, G.; Bravo, D.; Caccianiga, B.; Calaprice, F.; Caminata, A.; Cavalcante, P.; Chepurnov, A.; D'Angelo, D.; Derbin, A.; Di Noto, L.; Drachnev, I.; Etenko, A.; Fomenko, K.; Franco, D.; Gabriele, F.; Galbiati, C.; Ghiano, C.; Giammarchi, M.; Goeger-Neff, M.; Goretti, A.; Gromov, M.; Hagner, C.; Hungerford, E.; Ianni, Aldo; Ianni, Andrea; Jedrzejczak, K.; Kaiser, M.; Kobychev, V.; Korablev, D.; Korga, G.; Kryn, D.; Laubenstein, M.; Lehnert, B.; Litvinovich, E.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Lukyanchenko, G.; Machulin, I.; Manecki, S.; Maneschg, W.; Marcocci, S.; Meroni, E.; Meyer, M.; Miramonti, L.; Misiaszek, M.; Montuschi, M.; Mosteiro, P.; Muratova, V.; Neumair, B.; Oberauer, L.; Obolensky, M.; Ortica, F.; Pallavicini, M.; Papp, L.; Perasso, L.; Pocar, A.; Ranucci, G.; Razeto, A.; Re, A.; Romani, A.; Roncin, R.; Rossi, N.; Schönert, S.; Semenov, D.; Simgen, H.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sukhotin, S.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Thurn, J.; Toropova, M.; Unzhakov, E.; Vishneva, A.; Vogelaar, R. B.; von Feilitzsch, F.; Wang, H.; Weinz, S.; Winter, J.; Wojcik, M.; Wurm, M.; Yokley, Z.; Zaimidoroga, O.; Zavatarelli, S.; Zuber, K.; Zuzel, G.

2016-02-01

The detection of neutrinos emitted in the CNO reactions in the Sun is one of the ambitious goals of Borexino Phase-II. A measurement of CNO neutrinos would be a milestone in astrophysics, and would allow to solve serious issues in current solar models. A precise measurement of the rate of neutrinos from the pep reaction would allow to investigate neutrino oscillations in the MSW transition region. The pep and CNO solar neutrino physics, the measurement in Borexino Phase-I and the perspectives for the new phase are reviewed in this proceeding.

Assessment of urban green space structures and their quality from a multidimensional perspective.

PubMed

Daniels, Benjamin; Zaunbrecher, Barbara S; Paas, Bastian; Ottermanns, Richard; Ziefle, Martina; Roß-Nickoll, Martina

2018-02-15

Facing the growing amount of people living in cities and, at the same time, the need for a compact and sustainable urban development to mitigate urban sprawl, it becomes increasingly important that green spaces in compact cities are designed to meet the various needs within an urban environment. Urban green spaces have a multitude of functions: Maintaining ecological processes and resulting services, e.g. providing habitat for animals and plants, providing a beneficial city microclimate as well as recreational space for citizens. Regarding these requirements, currently existing assessment procedures for green spaces have some major shortcomings, which are discussed in this paper. It is argued why a more detailed spatial level as well as a distinction between natural and artificial varieties of structural elements is justified and needed and how the assessment of urban green spaces benefits from the multidimensional perspective that is applied. By analyzing a selection of structural elements from an ecological, microclimatic and social perspective, indicator values are derived and a new, holistic metrics 1 is proposed. The results of the integrated analysis led to two major findings: first, that for some elements, the evaluation differs to a great extent between the different perspectives (disciplines) and second, that natural and artificial varieties are, in most cases, evaluated considerably different from each other. The differences between the perspectives call for an integrative planning policy which acknowledges the varying contribution of a structural element to different purposes (ecological, microclimatic, social) as well as a discussion about the prioritization of those purposes. The differences in the evaluation of natural vs. artificial elements verify the assumption that indicators which consider only generic elements fail to account for those refinements and are thus less suitable for planning and assessment purposes. Implications, challenges and scenarios for the application of such a metrics are finally discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

An Architecture, System Engineering, and Acquisition Approach for Space System Software Resiliency

NASA Astrophysics Data System (ADS)

Phillips, Dewanne Marie

Software intensive space systems can harbor defects and vulnerabilities that may enable external adversaries or malicious insiders to disrupt or disable system functions, risking mission compromise or loss. Mitigating this risk demands a sustained focus on the security and resiliency of the system architecture including software, hardware, and other components. Robust software engineering practices contribute to the foundation of a resilient system so that the system "can take a hit to a critical component and recover in a known, bounded, and generally acceptable period of time". Software resiliency must be a priority and addressed early in the life cycle development to contribute a secure and dependable space system. Those who develop, implement, and operate software intensive space systems must determine the factors and systems engineering practices to address when investing in software resiliency. This dissertation offers methodical approaches for improving space system resiliency through software architecture design, system engineering, increased software security, thereby reducing the risk of latent software defects and vulnerabilities. By providing greater attention to the early life cycle phases of development, we can alter the engineering process to help detect, eliminate, and avoid vulnerabilities before space systems are delivered. To achieve this objective, this dissertation will identify knowledge, techniques, and tools that engineers and managers can utilize to help them recognize how vulnerabilities are produced and discovered so that they can learn to circumvent them in future efforts. We conducted a systematic review of existing architectural practices, standards, security and coding practices, various threats, defects, and vulnerabilities that impact space systems from hundreds of relevant publications and interviews of subject matter experts. We expanded on the system-level body of knowledge for resiliency and identified a new software architecture framework and acquisition methodology to improve the resiliency of space systems from a software perspective with an emphasis on the early phases of the systems engineering life cycle. This methodology involves seven steps: 1) Define technical resiliency requirements, 1a) Identify standards/policy for software resiliency, 2) Develop a request for proposal (RFP)/statement of work (SOW) for resilient space systems software, 3) Define software resiliency goals for space systems, 4) Establish software resiliency quality attributes, 5) Perform architectural tradeoffs and identify risks, 6) Conduct architecture assessments as part of the procurement process, and 7) Ascertain space system software architecture resiliency metrics. Data illustrates that software vulnerabilities can lead to opportunities for malicious cyber activities, which could degrade the space mission capability for the user community. Reducing the number of vulnerabilities by improving architecture and software system engineering practices can contribute to making space systems more resilient. Since cyber-attacks are enabled by shortfalls in software, robust software engineering practices and an architectural design are foundational to resiliency, which is a quality that allows the system to "take a hit to a critical component and recover in a known, bounded, and generally acceptable period of time". To achieve software resiliency for space systems, acquirers and suppliers must identify relevant factors and systems engineering practices to apply across the lifecycle, in software requirements analysis, architecture development, design, implementation, verification and validation, and maintenance phases.

Health Disparities and Discrimination: Three Perspectives

PubMed Central

Ndiaye, Khadidiatou; Krieger, Janice R.; Warren, Jennifer R.; Hecht, Michael L.; Okuyemi, Kola

2010-01-01

This article presents three perspectives on health discrimination and disparities, organized around different conceptualizations of the way “space” perpetuates health disparities. The first two perspectives are grounded in conceptualizing space in a physical sense by exploring the manifestation of discrimination as a problem both among and within nations. The third perspective juxtaposes geographical space with cyberspace. The internet, with its ability to blur sense of place, social demarcations, and behavior is often considered a panacea that can eliminate the health disparities. The internet, however, may not be fulfilling its promise as an equal source of health information for all and disparities related to international and rural geography remain problematic. Solutions are proposed for reducing health disparities based on The Principle of Cultural Grounding (Hecht & Krieger, 2006; Hecht & Miller-Day, in press). PMID:20694161

New Perspectives on an Old Approach

ERIC Educational Resources Information Center

Rosania, MaryJo

2006-01-01

Since the Renaissance, artists have used one- and two-point perspective to describe space in their work. After the release of artist David Hockney's theory questioning the use of lenses and "Scientific America's" attempt to disprove Hockney's theories, perspective has gotten quite controversial. The art world's perplexity surrounding the concept…

Specific to Whose Body? Perspective-Taking and the Spatial Mapping of Valence

PubMed Central

Kominsky, Jonathan F.; Casasanto, Daniel

2013-01-01

People tend to associate the abstract concepts of “good” and “bad” with their fluent and disfluent sides of space, as determined by their natural handedness or by experimental manipulation (Casasanto, 2011). Here we investigated influences of spatial perspective taking on the spatialization of “good” and “bad.” In the first experiment, participants indicated where a schematically drawn cartoon character would locate “good” and “bad” stimuli. Right-handers tended to assign “good” to the right and “bad” to the left side of egocentric space when the character shared their spatial perspective, but when the character was rotated 180° this spatial mapping was reversed: good was assigned to the character’s right side, not the participant’s. The tendency to spatialize valence from the character’s perspective was stronger in the second experiment, when participants were shown a full-featured photograph of the character. In a third experiment, most participants not only spatialized “good” and “bad” from the character’s perspective, they also based their judgments on a salient attribute of the character’s body (an injured hand) rather than their own body. Taking another’s spatial perspective encourages people to compute space-valence mappings using an allocentric frame of reference, based on the fluency with which the other person could perform motor actions with their right or left hand. When people reason from their own spatial perspective, their judgments depend, in part, on the specifics of their bodies; when people reason from someone else’s perspective, their judgments may depend on the specifics of the other person’s body, instead. PMID:23717296

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akkelin, S.V.; Sinyukov, Yu.M.

A method allowing analysis of the overpopulation of phase space in heavy ion collisions in a model-independent way is proposed within the hydrodynamic approach. It makes it possible to extract a chemical potential of thermal pions at freeze-out, irrespective of the form of freeze-out (isothermal) hypersurface in Minkowski space and transverse flows on it. The contributions of resonance (with masses up to 2 GeV) decays to spectra, interferometry volumes, and phase-space densities are calculated and discussed in detail. The estimates of average phase-space densities and chemical potentials of thermal pions are obtained for SPS and RHIC energies. They demonstrate thatmore » multibosonic phenomena at those energies might be considered as a correction factor rather than as a significant physical effect. The analysis of the evolution of the pion average phase-space density in chemically frozen hadron systems shows that it is almost constant or slightly increases with time while the particle density and phase-space density at each space point decreases rapidly during the system's expansion. We found that, unlike the particle density, the average phase-space density has no direct link to the freeze-out criterion and final thermodynamic parameters, being connected rather to the initial phase-space density of hadronic matter formed in relativistic nucleus-nucleus collisions.« less

Prospective of Photon Propulsion for Interstellar Flight

NASA Astrophysics Data System (ADS)

Bae, Young K.

Mastering photon propulsion is proposed to be the key to overcoming the limit of the current propulsion technology based on conventional rocketry and potentially opening a new space era. A perspective on photon propulsion is presented here to elucidate that interstellar manned roundtrip flight could be achievable in a century within a frame of exiting scientific principles, once the required existing technologies are further developed. It is shown that the developmental pathway towards the interstellar flight demands not only technological breakthroughs, but consistent long-term world-scale economic interest and investment. Such interest and investment will result from positive financial returns from routine interstellar commutes that can transport highly valuable commodities in a profitable manner. The Photonic Railway, a permanent energy-efficient transportation structure based on the Beamed-Laser Propulsion (BLP) by Forward and the Photonic Laser Thruster (PLT) by the author, is proposed to enable such routine interstellar commutes via Spacetrains. A four-phased evolutionary developmental pathway towards the Interstellar Photonic Railway is proposed. Each phase poses evolutionary, yet daunting, technological and financial challenges that need to be overcome within each time frame of 20 _ 30 years, and is projected to generate multitudes of applications that would lead to sustainable reinvestment into its development. If successfully developed, the Photonic Railway would bring about a quantum leap in the human economic and social interests in space from explorations to terraforming, mining, colonization, and permanent habitation in exoplanets.

Disentangling the Cosmic Web with Lagrangian Submanifold

NASA Astrophysics Data System (ADS)

Shandarin, Sergei F.; Medvedev, Mikhail V.

2016-10-01

The Cosmic Web is a complicated highly-entangled geometrical object. Remarkably it has formed from practically Gaussian initial conditions, which may be regarded as the simplest departure from exactly uniform universe in purely deterministic mapping. The full complexity of the web is revealed neither in configuration no velocity spaces considered separately. It can be fully appreciated only in six-dimensional (6D) phase space. However, studies of the phase space is complicated by the fact that every projection of it on a three-dimensional (3D) space is multivalued and contained caustics. In addition phase space is not a metric space that complicates studies of geometry. We suggest to use Lagrangian submanifold i.e., x = x(q), where both x and q are 3D vectors instead of the phase space for studies the complexity of cosmic web in cosmological N-body dark matter simulations. Being fully equivalent in dynamical sense to the phase space it has an advantage of being a single valued and also metric space.

2004 Space Report: Environment and Strategy for Space Research at NATO’s Research and Technology Organisation (RTO) (Compte rendu Espace 2004 : Environnement et strat gie de la recherche spatiale de l’Organisation pour la recherche et la technologie de l’OTAN)

DTIC Science & Technology

2007-02-01

cost vs . return perspective that limits researcher participation in RTO forums. Organizational barriers to more focused attention on space research...AND TECHNOLOGY ORGANISATION ( RTO ) RTO -TM-SPD-001 3 than “open-ended basic research” leads to a cost vs . return perspective that limits free...NORTH ATLANTIC TREATY ORGANISATION RESEARCH AND TECHNOLOGY ORGANISATION AC/323(SPD-001)TP/01 www.rta.nato.int RTO TECHNICAL MEMORANDUM

International space research perspectives of commercialization for German industry

NASA Technical Reports Server (NTRS)

Jordan, H. L.

1985-01-01

A brief overview of space flight activities is presented. West German contributions to satellite mapping, communication satellites, navigation, Spacelab, diffusion under weightlessness, crystal growth in space, metal bonding, and biochemistry are described. The future of the research in the space station is analyzed.

Phase space methods in HMD systems

NASA Astrophysics Data System (ADS)

Babington, James

2017-06-01

We consider using phase space techniques and methods in analysing optical ray propagation in head mounted display systems. Two examples are considered that illustrate the concepts and methods. Firstly, a shark tooth freeform geometry, and secondly, a waveguide geometry that replicates a pupil in one dimension. Classical optics and imaging in particular provide a natural stage to employ phase space techniques, albeit as a constrained system. We consider how phase space provides a global picture of the physical ray trace data. As such, this gives a complete optical world history of all of the rays propagating through the system. Using this data one can look at, for example, how aberrations arise on a surface by surface basis. These can be extracted numerically from phase space diagrams in the example of a freeform imaging prism. For the waveguide geometry, phase space diagrams provide a way of illustrating how replicated pupils behave and what these imply for design considerations such as tolerances.

The ESA Herschel Space Observatory -first year achievements and early science highlights

NASA Astrophysics Data System (ADS)

Pilbratt, Göran

The Herschel Space Observatory was suc-cessfully launched on 14 May 2009, carried into space by an Ariane 5 ECA launcher together with the second passenger Planck, both spacecraft being injected into transfer orbits towards L2 with exquisite precision. Herschel is the most recent observatory mission in the European Space Agency (ESA) science programme. It carries a 3.5 metre diameter Cassegrain passively cooled monolithic silicon carbide telescope. The focal plane units of the science payload complement -two cameras/medium resolution imaging spectrometers, the Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging REceiver (SPIRE), and the very high resolution Heterodyne Instrument for the Far-Infrared (HIFI) spectrometer -are housed in a superfluid helium cryostat. Herschel is the first large aperture space infrared observatory, it builds on previous infrared space missions including the IRAS, ISO, AKARI, and Spitzer observatories, by offering a much larger telescope and pushes towards longer wavelengths. It will perform imaging photometry and spectroscopy in the far infrared and submillimetre part of the spectrum, covering approximately the 55-672 micron range. I will describe Herschel and its science capabilities putting it into perspective. Herschel is designed to observe the 'cool universe'; the key science objectives include star and galaxy formation and evolution, and in particular the physics, dynamics, and chemistry of the interstellar medium and its molecular clouds, the wombs of the stars and planets. Herschel is currently opening a new window to study how the universe has evolved to become the universe we see today, and how our star the sun, our planet the earth, and we ourselves fit in. I will outline the early inflight operations of Herschel and the transition from launch and early operational phases into the routine science phase. I will present the demonstrated science capabilities and provide examples of scientific highlights to date. Herschel has been designed to offer a minimum of 3 years of routine science observations. Nominally 20,000 hours will be available for astronomy, 32(OT) offered to the general astronomical community through a standard competitive proposal procedure. I will describe future observing opportunities.

Human migration to space: Alternative technological approaches for long-term adaptation to extraterrestrial environments and the implications for human evolution

NASA Astrophysics Data System (ADS)

Lockard, Elizabeth Song

As humans embark upon the next phase of Space exploration---establishing human outposts in low-Earth orbit, on the Moon, and on Mars---the scope of human factors must expand beyond the meager requirements for short-term missions to Space to include issues of comfort and well-being necessary for long-term durations. However, to habitate---to dwell in a place---implies more than creature comforts in order to adapt. Human factors research must also include a phenomenological perspective---an understanding of how we experience the places we live in---in order for a community to be robust and to thrive. The first phase of migration will be an especially tenuous one requiring intensive technological intervention. The modes by which those technologies are implemented will have significant bearing on the process of human adaptation: the nature of the mediation can be either one of domination, subordination, avoidance, or integration. Ultimately, adaptation is best ensured if symbiotic processes of negotiation and cooperation between subject and environment are espoused over acts of conquest or acquiescence. The adaptive mechanisms we choose to develop and employ will have wider implications for long-range human evolution. The transformations we will undergo will be influenced by both the initial decision to migrate to Space (technological), as well as the actual conditions of Space (environmental). Migration to extraterrestrial environments will be unequivocally the most profound catalyst for evolution in the history of humankind---not only for the human species itself but also for the new environments we will eventually inhabit. At the same time, we also find ourselves---via a new generation of bio-, nano-, and digital technologies---in the position to consciously and willfully direct our own evolution. Technology has always been transformative, but in the not-so-distant future, we will soon possess the capacity to radically re-invent ourselves in almost any way conceivable. The discourse on human evolution in Space must be situated in the confluence of these two variables.

Embedded Managers in Informal Learning Spaces

ERIC Educational Resources Information Center

Raisin, Victoria; Fennewald, Joseph

2016-01-01

Many universities have decided to invest in updating their informal learning spaces. One decision to be made in planning the space is how to staff it. The researchers carried out a qualitative case study to better understand the perspective of learning space managers who work in offices within their assigned space. The research generated six…

Current gaps in understanding and predicting space weather: An operations perspective

NASA Astrophysics Data System (ADS)

Murtagh, W. J.

2016-12-01

The NOAA Space Weather Prediction Center (SWPC), one of the nine National Weather Service (NWS) National Centers for Environmental Prediction, is the Nation's official source for space weather alerts and warnings. Space weather effects the technology that forms the backbone of global economic vitality and national security, including satellite and airline operations, communications networks, and the electric power grid. Many of SWPC's over 48,000 subscribers rely on space weather forecasts for critical decision making. But extraordinary gaps still exist in our ability to meet customer needs for accurate and timely space weather forecasts and warnings. The 2015 National Space Weather Strategy recognizes that it is imperative that we improve the fundamental understanding of space weather and increase the accuracy, reliability, and timeliness of space-weather observations and forecasts in support of the growing demands. In this talk we provide a broad perspective of the key challenges that currently limit the forecaster's ability to better understand and predict space weather. We also examine the impact of these limitations on the end-user community.

Husimi function and phase-space analysis of bilayer quantum Hall systems at ν = 2/λ

NASA Astrophysics Data System (ADS)

Calixto, M.; Peón-Nieto, C.

2018-05-01

We propose localization measures in phase space of the ground state of bilayer quantum Hall systems at fractional filling factors , to characterize the three quantum phases (shortly denoted by spin, canted and ppin) for arbitrary -isospin λ. We use a coherent state (Bargmann) representation of quantum states, as holomorphic functions in the 8-dimensional Grassmannian phase-space (a higher-dimensional generalization of the Haldane’s 2-dimensional sphere ). We quantify the localization (inverse volume) of the ground state wave function in phase-space throughout the phase diagram (i.e. as a function of Zeeman, tunneling, layer distance, etc, control parameters) with the Husimi function second moment, a kind of inverse participation ratio that behaves as an order parameter. Then we visualize the different ground state structure in phase space of the three quantum phases, the canted phase displaying a much higher delocalization (a Schrödinger cat structure) than the spin and ppin phases, where the ground state is highly coherent. We find a good agreement between analytic (variational) and numeric diagonalization results.

On the importance of an accurate representation of the initial state of the system in classical dynamics simulations

NASA Astrophysics Data System (ADS)

García-Vela, A.

2000-05-01

A definition of a quantum-type phase-space distribution is proposed in order to represent the initial state of the system in a classical dynamics simulation. The central idea is to define an initial quantum phase-space state of the system as the direct product of the coordinate and momentum representations of the quantum initial state. The phase-space distribution is then obtained as the square modulus of this phase-space state. The resulting phase-space distribution closely resembles the quantum nature of the system initial state. The initial conditions are sampled with the distribution, using a grid technique in phase space. With this type of sampling the distribution of initial conditions reproduces more faithfully the shape of the original phase-space distribution. The method is applied to generate initial conditions describing the three-dimensional state of the Ar-HCl cluster prepared by ultraviolet excitation. The photodissociation dynamics is simulated by classical trajectories, and the results are compared with those of a wave packet calculation. The classical and quantum descriptions are found in good agreement for those dynamical events less subject to quantum effects. The classical result fails to reproduce the quantum mechanical one for the more strongly quantum features of the dynamics. The properties and applicability of the phase-space distribution and the sampling technique proposed are discussed.

Experimental Evidence for a Structural-Dynamical Transition in Trajectory Space.

PubMed

Pinchaipat, Rattachai; Campo, Matteo; Turci, Francesco; Hallett, James E; Speck, Thomas; Royall, C Patrick

2017-07-14

Among the key insights into the glass transition has been the identification of a nonequilibrium phase transition in trajectory space which reveals phase coexistence between the normal supercooled liquid (active phase) and a glassy state (inactive phase). Here, we present evidence that such a transition occurs in experiments. In colloidal hard spheres, we find a non-Gaussian distribution of trajectories leaning towards those rich in locally favored structures (LFSs), associated with the emergence of slow dynamics. This we interpret as evidence for a nonequilibrium transition to an inactive LFS-rich phase. Reweighting trajectories reveals a first-order phase transition in trajectory space between a normal liquid and a LFS-rich phase. We also find evidence for a purely dynamical transition in trajectory space.

Body ownership and attention in the mirror: insights from somatoparaphrenia and the rubber hand illusion.

PubMed

Jenkinson, Paul M; Haggard, Patrick; Ferreira, Nicola C; Fotopoulou, Aikaterini

2013-07-01

The brain receives and synthesises information about the body from different modalities, coordinates and perspectives, and affords us with a coherent and stable sense of body ownership. We studied this sense in a somatoparaphrenic patient and three control patients, all with unilateral right-hemisphere lesions. We experimentally manipulated the visual perspective (direct- versus mirror-view) and spatial attention (drawn to peripersonal space versus extrapersonal space) in an experiment involving recognising one's own hand. The somatoparaphrenic patient denied limb ownership in all direct view trials, but viewing the hand via a mirror significantly increased ownership. The extent of this increase depended on spatial attention; when attention was drawn to the extrapersonal space (near-the-mirror) the patient showed a near perfect recognition of her arm in the mirror, while when attention was drawn to peripersonal space (near-the-body) the patient recognised her arm in only half the mirror trials. In a supplementary experiment, we used the Rubber Hand Illusion to manipulate the same factors in healthy controls. Ownership of the rubber hand occurred in both direct and mirror view, but shifting attention between peripersonal and extrapersonal space had no effect on rubber-hand ownership. We conclude that the isolation of visual perspectives on the body and the division of attention between two different locations is not sufficient to affect body ownership in healthy individuals and right hemisphere controls. However, in somatoparaphrenia, where first-person body ownership and stimulus-driven attention are impaired by lesions to a right-hemisphere ventral attentional-network, the body can nevertheless be recognised as one's own if perceived in a third-person visual perspective and particularly if top-down, spatial attention is directed away from peripersonal space. Copyright © 2013 Elsevier Ltd. All rights reserved.

The Role of Open Space in Urban Neighbourhoods for Health-Related Lifestyle

PubMed Central

Lestan, Katarina Ana; Eržen, Ivan; Golobič, Mojca

2014-01-01

The research reported in this paper addresses the relationship between quality of open space and health related lifestyle in urban residential areas. The research was performed in the residential developments in Ljubljana, Slovenia, dating from the time of political and economic changes in the early nineties. Compared to the older neighborhoods, these are typically single-use residential areas, with small open spaces and poor landscape design. The research is concerned with the quality of life in these areas, especially from the perspective of the vulnerable users, like the elderly and children. Both depend on easily accessible green areas in close proximity to their homes. The hypothesis is that the poor open space quality affects their health-related behavior and their perceived health status. The research has three methodological phases: (1) a comparison between urban residential areas by criteria describing their physical characteristics; (2) behavior observation and mapping and (3) a resident opinion survey. The results confirm differences between open spaces of the selected residential areas as well as their relation with outdoor activities: a lack of outdoor programs correlates with poor variety of outdoor activities, limited to transition type, less time spent outdoors and lower satisfaction with their home environment. The survey also disclosed a strong influence of a set of socio-economic variables such as education and economic status on physical activity and self-perceived health status of people. The results therefore confirm the hypothesis especially for less affluent and educated; i.e., vulnerable groups. PMID:25003173

Operational Space Weather Needs - Perspectives from SEASONS 2014

NASA Astrophysics Data System (ADS)

Comberiate, J.; Kelly, M. A.; Paxton, L. J.; Schaefer, R. K.; Bust, G. S.; Sotirelis, T.; Fox, N. J.

2014-12-01

A key challenge for the operational space weather community is the gap between the latest scientific data, models, methods, and indices and those that are currently used in operational systems. The November 2014 SEASONS (Space Environment Applications, Systems, and Operations for National Security) Workshop at JHU/APL in Laurel, Maryland, brings together representatives from the operational and scientific communities. The theme of SEASONS 2014 is "Beyond Climatology," with a focus on how space weather events threaten operational assets and disrupt missions. Here we present perspectives from SEASONS 2014 on new observations, models in development, and forecasting methods that are of interest to the operational space weather community. Highlighted topics include ionospheric data assimilation and forecasting models, HF propagation models, radiation belt observations, and energetic particle modeling. The SEASONS 2014 web site can be found at https://secwww.jhuapl.edu/SEASONS/

Future perspectives on space psychology: Recommendations on psychosocial and neurobehavioural aspects of human spaceflight

NASA Astrophysics Data System (ADS)

De La Torre, Gabriel G.; van Baarsen, Berna; Ferlazzo, Fabio; Kanas, Nick; Weiss, Karine; Schneider, Stefan; Whiteley, Iya

2012-12-01

Recently the psychological effects of space flight have gained in attention. In uncovering the psychological challenges that individuals and teams can face, we need research options that integrate psychosocial aspects with behavioral, performance, technical and environmental issues. Future perspectives in Space Psychology and Human Spaceflight are reviewed in this paper. The topics covered include psychosocial and neurobehavioural aspects, neurocognitive testing tools, decision making, autonomy and delayed communications, well being, mental health, situational awareness, and methodology. Authors were members of a European Space Agency (ESA) Research Topical Team on Psychosocial and Behavioral Aspects of Human Spaceflight. They discuss the different topics under a common perspective of a theoretical and practical framework, showing interactions, relationships and possible solutions for the different aspects and variables in play. Recommendations for every topic are offered and summarized for future research in the field. The different proposed research ideas can be accomplished using analogs and simulation experiments, short- and long-duration bed rest, and in-flight microgravity studies. These topics are especially important for future Moon and Mars mission design and training.

Phase-locked laser array having a non-uniform spacing between lasing regions

NASA Technical Reports Server (NTRS)

Ackley, Donald E. (Inventor)

1986-01-01

A phase-locked semiconductor array wherein the lasing regions of the array are spaced an effective distance apart such that the modes of oscillation of the different lasing regions are phase-locked to one another. The center-to-center spacing between the lasing regions is non-uniform. This variation in spacing perturbs the preferred 180.degree. phase difference between adjacent lasing regions thereby providing an increased yield of arrays exhibiting a single-lobed, far-field radiation pattern.

An effective method to accurately calculate the phase space factors for β - β - decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neacsu, Andrei; Horoi, Mihai

2016-01-01

Accurate calculations of the electron phase space factors are necessary for reliable predictions of double-beta decay rates and for the analysis of the associated electron angular and energy distributions. Here, we present an effective method to calculate these phase space factors that takes into account the distorted Coulomb field of the daughter nucleus, yet it allows one to easily calculate the phase space factors with good accuracy relative to the most exact methods available in the recent literature.

A Strategy To Infuse a Global Perspective into Consumer Education.

ERIC Educational Resources Information Center

McGregor, Sue L. T.; Bourbonniere, Katherine

2002-01-01

A four-phase plan for delivering consumer education from a global perspective involves teachers in gaining familiarity with (1) the conventional approach to consumer education; (2) the cultures of globalization, capitalism, and consumerism; (3) the global perspective; and (4) integration of the three to create a global curriculum. (Contains 50…

Definition of technology development missions for early Space Station satellite servicing. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1984-01-01

The Executive Summary volume 1, includes an overview of both phases of the Definition of Technology Development Missions for Early Space Station Satellite Servicing. The primary purpose of Phase 1 of the Marshall Space Flight Center (MSFC) Satellite Servicing Phase 1 study was to establish requirements for demonstrating the capability of performing satellite servicing activities on a permanently manned Space Station in the early 1990s. The scope of Phase 1 included TDM definition, outlining of servicing objectives, derivation of initial Space Station servicing support requirements, and generation of the associated programmatic schedules and cost. The purpose of phase 2 of the satellite servicing study was to expand and refine the overall understanding of how best to use the manned space station as a test bed for demonstration of satellite servicing capabilities.

Energy content of stormtime ring current from phase space mapping simulations

NASA Technical Reports Server (NTRS)

Chen, Margaret W.; Schulz, Michael; Lyons, Larry R.

1993-01-01

We perform a phase space mapping study to estimate the enhancement in energy content that results from stormtime particle transport in the equatorial magnetosphere. Our pre-storm phase space distribution is based on a steady-state transport model. Using results from guiding-center simulations of ion transport during model storms having main phases of 3 hr, 6 hr, and 12 hr, we map phase space distributions of ring current protons from the pre-storm distribution in accordance with Liouville's theorem. We find that transport can account for the entire ten to twenty-fold increase in magnetospheric particle energy content typical of a major storm if a realistic stormtime enhancement of the phase space density f is imposed at the nightside tail plasma sheet (represented by an enhancement of f at the neutral line in our model).

Space Medicine: Shuttle - Space Station Crew Health and Safety Challenges for Exploration

NASA Technical Reports Server (NTRS)

Dervay, Joseph

2010-01-01

This slide presentation combines some views of the shuttle take off, and the shuttle and space station on orbit, and some views of the underwater astronaut training , with a general discussion of Space Medicine. It begins with a discussion of the some of the physiological issues of space flight. These include: Space Motion Sickness (SMS), Cardiovascular, Neurovestibular, Musculoskeletal, and Behavioral/Psycho-social. There is also discussion of the space environment and the issues that are posed including: Radiation, Toxic products and propellants, Habitability, Atmosphere, and Medical events. Included also is a discussion of the systems and crew training. There are also artists views of the Constellation vehicles, the planned lunar base, and extended lunar settlement. There are also slides showing the size of earth in perspective to the other planets, and the sun and the sun in perspective to other stars. There is also a discussion of the in-flight changes that occur in neural feedback that produces postural imbalance and loss of coordination after return.

Research on natural lighting in reading spaces of university libraries in Jinan under the perspective of energy-efficiency

NASA Astrophysics Data System (ADS)

Yang, Zengzhang

2017-11-01

The natural lighting design in the reading spaces of university libraries not only influences physical and mental health of readers but also concerns the energy consumption of the libraries. The scientific and rational design of natural lighting is the key to the design of energy saving for physical environment of the reading space. The paper elaborates the present situation and existed problems of natural lighting in reading spaces of university libraries across Jinan region based on characteristics of light climate of Jinan region and concrete utilization of reading spaces in university libraries, and combining field measurement, survey, research and data analysis of reading spaces in Shandong Women’s University’s library. The paper, under the perspective of energy-efficiency, puts forward proposals to improve natural lighting in the reading spaces of university libraries from five aspects, such as adjustment of interior layout, optimization of outer windows design, employment of the reflector panel, design lighting windows on inner walls and utilization of adjustable sun shading facilities.

Marshall Space Flight Center Faculty Fellowship Program

NASA Technical Reports Server (NTRS)

Six, N. F.; Damiani, R. (Compiler)

2017-01-01

The 2017 Marshall Faculty Fellowship Program involved 21 faculty in the laboratories and departments at Marshall Space Flight Center. These faculty engineers and scientists worked with NASA collaborators on NASA projects, bringing new perspectives and solutions to bear. This Technical Memorandum is a compilation of the research reports of the 2017 Marshall Faculty Fellowship program, along with the Program Announcement (Appendix A) and the Program Description (Appendix B). The research affected the following six areas: (1) Materials (2) Propulsion (3) Instrumentation (4) Spacecraft systems (5) Vehicle systems (6) Space science The materials investigations included composite structures, printing electronic circuits, degradation of materials by energetic particles, friction stir welding, Martian and Lunar regolith for in-situ construction, and polymers for additive manufacturing. Propulsion studies were completed on electric sails and low-power arcjets for use with green propellants. Instrumentation research involved heat pipes, neutrino detectors, and remote sensing. Spacecraft systems research was conducted on wireless technologies, layered pressure vessels, and two-phase flow. Vehicle systems studies were performed on life support-biofilm buildup and landing systems. In the space science area, the excitation of electromagnetic ion-cyclotron waves observed by the Magnetospheric Multiscale Mission provided insight regarding the propagation of these waves. Our goal is to continue the Marshall Faculty Fellowship Program funded by Center internal project offices. Faculty Fellows in this 2017 program represented the following minority-serving institutions: Alabama A&M University and Oglala Lakota College.

Space Weathering Perspectives on Europa Amidst the Tempest of the Jupiter Magnetospheric System

NASA Technical Reports Server (NTRS)

Cooper, J. F.; Hartle, R. E.; Lipatov, A. S.; Sittler, E. C.; Cassidy, T. A.; Ip. W.-H.

2010-01-01

Europa resides within a "perfect storm" tempest of extreme external field, plasma, and energetic particle interactions with the magnetospheric system of Jupiter. Missions to Europa must survive, functionally operate, make useful measurements, and return critical science data, while also providing full context on this ocean moon's response to the extreme environment. Related general perspectives on space weathering in the solar system are applied to mission and instrument science requirements for Europa.

Space Weather Research: Indian perspective

NASA Astrophysics Data System (ADS)

Bhardwaj, Anil; Pant, Tarun Kumar; Choudhary, R. K.; Nandy, Dibyendu; Manoharan, P. K.

2016-12-01

Space weather, just like its meteorological counterpart, is of extreme importance when it comes to its impact on terrestrial near- and far-space environments. In recent years, space weather research has acquired an important place as a thrust area of research having implications both in space science and technology. The presence of satellites and other technological systems from different nations in near-Earth space necessitates that one must have a comprehensive understanding not only of the origin and evolution of space weather processes but also of their impact on technology and terrestrial upper atmosphere. To address this aspect, nations across the globe including India have been investing in research concerning Sun, solar processes and their evolution from solar interior into the interplanetary space, and their impact on Earth's magnetosphere-ionosphere-thermosphere system. In India, over the years, a substantial amount of work has been done in each of these areas by various agencies/institutions. In fact, India has been, and continues to be, at the forefront of space research and has ambitious future programs concerning these areas encompassing space weather. This review aims at providing a glimpse of this Indian perspective on space weather research to the reader and presenting an up-to-date status of the same.

PLÉIADES: Responsiveness, Flexibility, Reactivity

NASA Astrophysics Data System (ADS)

Gabriel-Robez, C.; Lees, R.; Bernard, M.

2012-08-01

By the end of 2011, Astrium GEO-Information Services launched Pléiades 1, the first of two identical optical imaging satellites that will be operated on a phased orbit. This satellite system, designed by the French Space Agency, CNES, based upon French Defense specifications, will provide 50-cm products in record time. The overall aim of this paper is to describe the benefits of the innovative features of Pléiades 1 and its operations, so as to assess their combined potential in emergency situations, crisis recovery, regular monitoring or large area mapping. Specific care will be brought to describe the reactivity enabled by the system. Based on real-life examples, the paper will lead the analysis on the two main components of the system. On the one hand, the space segment will be presented through the following characteristics: revisit capacity, agility, acquisition capacity and acquisition scenarios (target, single-pass mosaics, stereo, tristereo, linear monitoring, persistent surveillance). On the other hand, the flexibility of the ground segment will be assessed. The benefits of multiple tasking plans per day, direct tasking capacity, automated processing and on-line ordering and delivering will be illustrated, tested and qualified for applications requiring a high level of responsiveness and reactivity. The presentation will end with a summary of the benefits of the space segment features and the flexibility of the ground segment, fine-tuned to answer both military and civilian / commercial needs. The analysis will be extended in the perspective of the second Pléiades' launch, highlighting the advantages of having two satellites operating on a phased orbit, affording a daily revisit anywhere on Earth, with very high resolution.

Space-Based Telemetry and Range Safety Project Ku-Band and Ka-Band Phased Array Antenna

NASA Technical Reports Server (NTRS)

Whiteman, Donald E.; Valencia, Lisa M.; Birr, Richard B.

2005-01-01

The National Aeronautics and Space Administration Space-Based Telemetry and Range Safety study is a multiphase project to increase data rates and flexibility and decrease costs by using space-based communications assets for telemetry during launches and landings. Phase 1 used standard S-band antennas with the Tracking and Data Relay Satellite System to obtain a baseline performance. The selection process and available resources for Phase 2 resulted in a Ku-band phased array antenna system. Several development efforts are under way for a Ka-band phased array antenna system for Phase 3. Each phase includes test flights to demonstrate performance and capabilities. Successful completion of this project will result in a set of communications requirements for the next generation of launch vehicles.

Ku- and Ka-Band Phased Array Antenna for the Space-Based Telemetry and Range Safety Project

NASA Technical Reports Server (NTRS)

Whiteman, Donald E.; Valencia, Lisa M.; Birr, Richard B.

2005-01-01

The National Aeronautics and Space Administration Space-Based Telemetry and Range Safety study is a multiphase project to increase data rates and flexibility and decrease costs by using space-based communications assets for telemetry during launches and landings. Phase 1 used standard S-band antennas with the Tracking and Data Relay Satellite System to obtain a baseline performance. The selection process and available resources for Phase 2 resulted in a Ku-band phased array antenna system. Several development efforts are under way for a Ka-band phased array antenna system for Phase 3. Each phase includes test flights to demonstrate performance and capabilities. Successful completion of this project will result in a set of communications requirements for the next generation of launch vehicles.

Phase space quantum mechanics - Direct

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nasiri, S.; Sobouti, Y.; Taati, F.

2006-09-15

Conventional approach to quantum mechanics in phase space (q,p), is to take the operator based quantum mechanics of Schroedinger, or an equivalent, and assign a c-number function in phase space to it. We propose to begin with a higher level of abstraction, in which the independence and the symmetric role of q and p is maintained throughout, and at once arrive at phase space state functions. Upon reduction to the q- or p-space the proposed formalism gives the conventional quantum mechanics, however, with a definite rule for ordering of factors of noncommuting observables. Further conceptual and practical merits of themore » formalism are demonstrated throughout the text.« less

Classical-Quantum Correspondence by Means of Probability Densities

NASA Technical Reports Server (NTRS)

Vegas, Gabino Torres; Morales-Guzman, J. D.

1996-01-01

Within the frame of the recently introduced phase space representation of non relativistic quantum mechanics, we propose a Lagrangian from which the phase space Schrodinger equation can be derived. From that Lagrangian, the associated conservation equations, according to Noether's theorem, are obtained. This shows that one can analyze quantum systems completely in phase space as it is done in coordinate space, without additional complications.

Space Phase III - The commercial era dawns

NASA Technical Reports Server (NTRS)

Allnutt, R. F.

1983-01-01

After the 'Phase I' of space activities, the period bounded by Sputnik and Apollo, 'Phase II', has been entered, a phase in which concerns over the use and the protection of space assets which support national security predominate. However, it is only when the commercial motive becomes prominent that human activity in new regions truly prospers and enters periods of exponential growth. It is believed that there are increasing signs that such a period, called 'Space Phase III', may be coming soon. A description is presented of developments and results upon which this conclusion is based. Since 1980, there have been three developments of great importance for the future of space activities. Six highly successful flights have demonstrated that the Space Shuttle concept works. A series of Soviet missions are related to the emergence of a capability to construct and service modular space stations. Successful tests of the European Ariane 1 indicate an end to U.S. monopoly with respect to the provision of launch services to the Western World.

Phase-space reaction network on a multisaddle energy landscape: HCN isomerization.

PubMed

Li, Chun-Biu; Matsunaga, Yasuhiro; Toda, Mikito; Komatsuzaki, Tamiki

2005-11-08

By using the HCN/CNH isomerization reaction as an illustrative vehicle of chemical reactions on multisaddle energy landscapes, we give explicit visualizations of molecular motions associated with a straight-through reaction tube in the phase space inside which all reactive trajectories pass from one basin to another, with eliminating recrossing trajectories in the configuration space. This visualization provides us with a chemical intuition of how chemical species "walk along" the reaction-rate slope in the multidimensional phase space compared with the intrinsic reaction path in the configuration space. The distinct nonergodic features in the two different HCN and CNH wells can be easily demonstrated by a section of Poincare surface of section in those potential minima, which predicts in a priori the pattern of trajectories residing in the potential well. We elucidate the global phase-space structure which gives rise to the non-Markovian dynamics or the dynamical correlation of sequential multisaddle chemical reactions. The phase-space structure relevant to the controllability of the product state in chemical reactions is also discussed.

Expanding the term "Design Space" in high performance liquid chromatography (I).

PubMed

Monks, K E; Rieger, H-J; Molnár, I

2011-12-15

The current article presents a novel approach to applying Quality by Design (QbD) principles to the development of high pressure reversed phase liquid chromatography (HPLC) methods. Four common critical parameters in HPLC--gradient time, temperature, pH of the aqueous eluent, and stationary phase--are evaluated within the Quality by Design framework by the means of computer modeling software and a column database, to a satisfactory degree. This work proposes the establishment of two mutually complimentary Design Spaces to fully depict a chromatographic method; one Column Design Space (CDS) and one Eluent Design Space (EDS) to describe the influence of the stationary phase and of the mobile phase on the separation selectivity, respectively. The merge of both Design Spaces into one is founded on the continuous nature of the mobile phase influence on retention and the great variety of the stationary phases available. Copyright © 2011 Elsevier B.V. All rights reserved.

An approach for automated fault diagnosis based on a fuzzy decision tree and boundary analysis of a reconstructed phase space.

PubMed

Aydin, Ilhan; Karakose, Mehmet; Akin, Erhan

2014-03-01

Although reconstructed phase space is one of the most powerful methods for analyzing a time series, it can fail in fault diagnosis of an induction motor when the appropriate pre-processing is not performed. Therefore, boundary analysis based a new feature extraction method in phase space is proposed for diagnosis of induction motor faults. The proposed approach requires the measurement of one phase current signal to construct the phase space representation. Each phase space is converted into an image, and the boundary of each image is extracted by a boundary detection algorithm. A fuzzy decision tree has been designed to detect broken rotor bars and broken connector faults. The results indicate that the proposed approach has a higher recognition rate than other methods on the same dataset. © 2013 ISA Published by ISA All rights reserved.

Transverse emittance and phase space program developed for use at the Fermilab A0 Photoinjector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thurman-Keup, R.; Johnson, A.S.; Lumpkin, A.H.

2011-03-01

The Fermilab A0 Photoinjector is a 16 MeV high intensity, high brightness electron linac developed for advanced accelerator R&D. One of the key parameters for the electron beam is the transverse beam emittance. Here we report on a newly developed MATLAB based GUI program used for transverse emittance measurements using the multi-slit technique. This program combines the image acquisition and post-processing tools for determining the transverse phase space parameters with uncertainties. An integral part of accelerator research is a measurement of the beam phase space. Measurements of the transverse phase space can be accomplished by a variety of methods includingmore » multiple screens separated by drift spaces, or by sampling phase space via pepper pots or slits. In any case, the measurement of the phase space parameters, in particular the emittance, can be drastically simplified and sped up by automating the measurement in an intuitive fashion utilizing a graphical interface. At the A0 Photoinjector (A0PI), the control system is DOOCS, which originated at DESY. In addition, there is a library for interfacing to MATLAB, a graphically capable numerical analysis package sold by The Mathworks. It is this graphical package which was chosen as the basis for a graphical phase space measurement system due to its combination of analysis and display capabilities.« less

NASA Research Announcement Phase 1 Report and Phase 2 Proposal for the Development of a Power Assisted Space Suit Glove Assembly

NASA Technical Reports Server (NTRS)

Cadogan, Dave; Lingo, Bob

1996-01-01

In July of 1996, ILC Dover was awarded Phase 1 of a contract for NASA to develop a prototype Power Assisted Space Suit glove to enhance the performance of astronauts during Extra-Vehicular Activity (EVA). This report summarizes the work performed to date on Phase 1, and details the work to be conducted on Phase 2 of the program. Phase 1 of the program consisted of research and review of related technical sources, concept brainstorming, baseline design development, modeling and analysis, component mock-up testing, and test data analysis. ILC worked in conjunction with the University of Maryland's Space Systems Laboratory (SSL) to develop the power assisted glove. Phase 2 activities will focus on the design maturation and the manufacture of a working prototype system. The prototype will be tested and evaluated in conjunction with existing space suit glove technology to determine the performance enhancement anticipated with the implementation of the power assisted joint technology in space suit gloves.

Efficient characterization of phase space mapping in axially symmetric optical systems

NASA Astrophysics Data System (ADS)

Barbero, Sergio; Portilla, Javier

2018-01-01

Phase space mapping, typically between an object and image plane, characterizes an optical system within a geometrical optics framework. We propose a novel conceptual frame to characterize the phase mapping in axially symmetric optical systems for arbitrary object locations, not restricted to a specific object plane. The idea is based on decomposing the phase mapping into a set of bivariate equations corresponding to different values of the radial coordinate on a specific object surface (most likely the entrance pupil). These equations are then approximated through bivariate Chebyshev interpolation at Chebyshev nodes, which guarantees uniform convergence. Additionally, we propose the use of a new concept (effective object phase space), defined as the set of points of the phase space at the first optical element (typically the entrance pupil) that are effectively mapped onto the image surface. The effective object phase space provides, by means of an inclusion test, a way to avoid tracing rays that do not reach the image surface.

Families of vector-like deformations of relativistic quantum phase spaces, twists and symmetries

NASA Astrophysics Data System (ADS)

Meljanac, Daniel; Meljanac, Stjepan; Pikutić, Danijel

2017-12-01

Families of vector-like deformed relativistic quantum phase spaces and corresponding realizations are analyzed. A method for a general construction of the star product is presented. The corresponding twist, expressed in terms of phase space coordinates, in the Hopf algebroid sense is presented. General linear realizations are considered and corresponding twists, in terms of momenta and Poincaré-Weyl generators or gl(n) generators are constructed and R-matrix is discussed. A classification of linear realizations leading to vector-like deformed phase spaces is given. There are three types of spaces: (i) commutative spaces, (ii) κ -Minkowski spaces and (iii) κ -Snyder spaces. The corresponding star products are (i) associative and commutative (but non-local), (ii) associative and non-commutative and (iii) non-associative and non-commutative, respectively. Twisted symmetry algebras are considered. Transposed twists and left-right dual algebras are presented. Finally, some physical applications are discussed.

The Right Stuff: A Look Back at Three Decades of Flight Controller Training for Space Shuttle Mission Operations

NASA Technical Reports Server (NTRS)

Dittemore, Gary D.; Bertels, Christie

2010-01-01

This paper will summarize the thirty-year history of Space Shuttle operations from the perspective of training in NASA Johnson Space Center's Mission Control Center. It will focus on training and development of flight controllers and instructors, and how training practices have evolved over the years as flight experience was gained, new technologies developed, and programmatic needs changed. Operations of human spaceflight systems is extremely complex, therefore the training and certification of operations personnel is a critical piece of ensuring mission success. Mission Control Center (MCC-H), at the Lyndon B. Johnson Space Center, in Houston, Texas manages mission operations for the Space Shuttle Program, including the training and certification of the astronauts and flight control teams. This paper will give an overview of a flight control team s makeup and responsibilities during a flight, and details on how those teams are trained and certified. The training methodology for developing flight controllers has evolved significantly over the last thirty years, while the core goals and competencies have remained the same. In addition, the facilities and tools used in the control center have evolved. These changes have been driven by many factors including lessons learned, technology, shuttle accidents, shifts in risk posture, and generational differences. Flight controllers will share their experiences in training and operating the Space Shuttle throughout the Program s history. A primary method used for training Space Shuttle flight control teams is by running mission simulations of the orbit, ascent, and entry phases, to truly "train like you fly." The audience will learn what it is like to perform a simulation as a shuttle flight controller. Finally, we will reflect on the lessons learned in training for the shuttle program, and how those could be applied to future human spaceflight endeavors.

Self-dual phase space for (3 +1 )-dimensional lattice Yang-Mills theory

NASA Astrophysics Data System (ADS)

Riello, Aldo

2018-01-01

I propose a self-dual deformation of the classical phase space of lattice Yang-Mills theory, in which both the electric and magnetic fluxes take value in the compact gauge Lie group. A local construction of the deformed phase space requires the machinery of "quasi-Hamiltonian spaces" by Alekseev et al., which is reviewed here. The results is a full-fledged finite-dimensional and gauge-invariant phase space, the self-duality properties of which are largely enhanced in (3 +1 ) spacetime dimensions. This enhancement is due to a correspondence with the moduli space of an auxiliary noncommutative flat connection living on a Riemann surface defined from the lattice itself, which in turn equips the duality between electric and magnetic fluxes with a neat geometrical interpretation in terms of a Heegaard splitting of the space manifold. Finally, I discuss the consequences of the proposed deformation on the quantization of the phase space, its quantum gravitational interpretation, as well as its relevance for the construction of (3 +1 )-dimensional topological field theories with defects.

Adult Perspectives on Structured vs. Unstructured Play in Early Childhood Environmental Education

ERIC Educational Resources Information Center

Hunter, Joshua; Graves, Cherie; Bodensteiner, Anne

2017-01-01

In this research report, the authors explore an early childhood center as it transitions from a traditional playground to an outdoor classroom. Herein, the first phase of this qualitative research project is introduced and a central finding of adult perspectives is explored. The tension inherent in the various adult perspectives concerning the…

Video Perspectivity Meets Wild and Crazy Teens: A Design Ethnography

ERIC Educational Resources Information Center

Goldman, Ricki

2004-01-01

This article is a digital video design ethnography describing the first phase of introducing a perspectivity meme into a classroom. A meme is an idea that spreads throughout a system. A perspectivity meme is the idea that people who share their viewpoints and interpretations will gradually affect role changes in the learning environment. They will…

Longitudinal phase space tomography using a booster cavity at PITZ

NASA Astrophysics Data System (ADS)

Malyutin, D.; Gross, M.; Isaev, I.; Khojoyan, M.; Kourkafas, G.; Krasilnikov, M.; Marchetti, B.; Otevrel, M.; Stephan, F.; Vashchenko, G.

2017-11-01

The knowledge of the longitudinal phase space (LPS) of electron beams is of great importance for optimizing the performance of high brightness photo injectors. To get the longitudinal phase space of an electron bunch in a linear accelerator a tomographic technique can be used. The method is based on measurements of the bunch momentum spectra while varying the bunch energy chirp. The energy chirp can be varied by one of the RF accelerating structures in the accelerator and the resulting momentum distribution can be measured with a dipole spectrometer further downstream. As a result, the longitudinal phase space can be reconstructed. Application of the tomographic technique for reconstruction of the longitudinal phase space is introduced in detail in this paper. Measurement results from the PITZ facility are shown and analyzed.

A Phase-Space Approach to Collisionless Stellar Systems Using a Particle Method

NASA Astrophysics Data System (ADS)

Hozumi, Shunsuke

1997-10-01

A particle method for reproducing the phase space of collisionless stellar systems is described. The key idea originates in Liouville's theorem, which states that the distribution function (DF) at time t can be derived from tracing necessary orbits back to t = 0. To make this procedure feasible, a self-consistent field (SCF) method for solving Poisson's equation is adopted to compute the orbits of arbitrary stars. As an example, for the violent relaxation of a uniform density sphere, the phase-space evolution generated by the current method is compared to that obtained with a phase-space method for integrating the collisionless Boltzmann equation, on the assumption of spherical symmetry. Excellent agreement is found between the two methods if an optimal basis set for the SCF technique is chosen. Since this reproduction method requires only the functional form of initial DFs and does not require any assumptions to be made about the symmetry of the system, success in reproducing the phase-space evolution implies that there would be no need of directly solving the collisionless Boltzmann equation in order to access phase space even for systems without any special symmetries. The effects of basis sets used in SCF simulations on the reproduced phase space are also discussed.

Foundation-industry relationships--a new business model joint-venture philanthropy in therapy development.

PubMed

Bartek, Ronald J

2014-01-01

The business model for medical therapy development has changed drastically. Large companies that once conducted their own Research and Development (R&D) and funded all the preclinical studies, all phases of clinical development and marketing of the products are increasingly turning to others for more and more of the earlier work in hopes of being able to in-license a de-risked program well downstream, take it through the final phases of clinical development and into the marketplace. This new paradigm has required patient-advocacy foundations, especially in the rare-disease space, to become far more effective in building relationships with all the players along the therapy-development pathway -- academic scientists, government agencies, other foundations with overlapping interests, biotechs, small biopharmaceutical entities and even the larger industry companies. From the perspective of the patient-advocacy community, these increasingly essential public-private partnerships have taken on the nature of what could be called joint-venture philanthropy and involve a broad spectrum of collaborations and financial relationships between foundations and industry partners that are not without concerns about potential conflicts of interest.

Oxygen-enabled control of Dzyaloshinskii-Moriya Interaction in ultra-thin magnetic films.

PubMed

Belabbes, Abderrezak; Bihlmayer, Gustav; Blügel, Stefan; Manchon, Aurélien

2016-04-22

The search for chiral magnetic textures in systems lacking spatial inversion symmetry has attracted a massive amount of interest in the recent years with the real space observation of novel exotic magnetic phases such as skyrmions lattices, but also domain walls and spin spirals with a defined chirality. The electrical control of these textures offers thrilling perspectives in terms of fast and robust ultrahigh density data manipulation. A powerful ingredient commonly used to stabilize chiral magnetic states is the so-called Dzyaloshinskii-Moriya interaction (DMI) arising from spin-orbit coupling in inversion asymmetric magnets. Such a large antisymmetric exchange has been obtained at interfaces between heavy metals and transition metal ferromagnets, resulting in spin spirals and nanoskyrmion lattices. Here, using relativistic first-principles calculations, we demonstrate that the magnitude and sign of DMI can be entirely controlled by tuning the oxygen coverage of the magnetic film, therefore enabling the smart design of chiral magnetism in ultra-thin films. We anticipate that these results extend to other electronegative ions and suggest the possibility of electrical tuning of exotic magnetic phases.

Oxygen-enabled control of Dzyaloshinskii-Moriya Interaction in ultra-thin magnetic films

PubMed Central

Belabbes, Abderrezak; Bihlmayer, Gustav; Blügel, Stefan; Manchon, Aurélien

2016-01-01

The search for chiral magnetic textures in systems lacking spatial inversion symmetry has attracted a massive amount of interest in the recent years with the real space observation of novel exotic magnetic phases such as skyrmions lattices, but also domain walls and spin spirals with a defined chirality. The electrical control of these textures offers thrilling perspectives in terms of fast and robust ultrahigh density data manipulation. A powerful ingredient commonly used to stabilize chiral magnetic states is the so-called Dzyaloshinskii-Moriya interaction (DMI) arising from spin-orbit coupling in inversion asymmetric magnets. Such a large antisymmetric exchange has been obtained at interfaces between heavy metals and transition metal ferromagnets, resulting in spin spirals and nanoskyrmion lattices. Here, using relativistic first-principles calculations, we demonstrate that the magnitude and sign of DMI can be entirely controlled by tuning the oxygen coverage of the magnetic film, therefore enabling the smart design of chiral magnetism in ultra-thin films. We anticipate that these results extend to other electronegative ions and suggest the possibility of electrical tuning of exotic magnetic phases. PMID:27103448

Orbital angular momentum mode groups multiplexing transmission over 2.6-km conventional multi-mode fiber.

PubMed

Zhu, Long; Wang, Andong; Chen, Shi; Liu, Jun; Mo, Qi; Du, Cheng; Wang, Jian

2017-10-16

Twisted light carrying orbital angular momentum (OAM) is a special kind of structured light that has a helical phase front, a phase singularity, and a doughnut intensity profile. Beyond widespread developments in manipulation, microscopy, metrology, astronomy, nonlinear and quantum optics, OAM-carrying twisted light has seen emerging application of optical communications in free space and specially designed fibers. Instead of specialty fibers, here we show the direct use of a conventional graded-index multi-mode fiber (MMF) for OAM communications. By exploiting fiber-compatible mode exciting and filtering elements, we excite the first four OAM mode groups in an MMF. We demonstrate 2.6-km MMF transmission using four data-carrying OAM mode groups (OAM 0,1 , OAM +1,1 /OAM -1,1 , OAM +2,1 , OAM +3,1 ). Moreover, we demonstrate two data-carrying OAM mode groups multiplexing transmission over the 2.6-km MMF with low-level crosstalk free of multiple-input multiple-output digital signal processing (MIMO-DSP). The demonstrations may open up new perspectives to fiber-based OAM communication/non-communication applications using already existing conventional fibers.

Recent results from DAMA/LIBRA - phase1 and perspectives

NASA Astrophysics Data System (ADS)

Bernabei, R.; Belli, P.; d'Angelo, S.; Di Marco, A.; Montecchia, F.; d'Angelo, A.; Incicchitti, A.; Cappella, F.; Caracciolo, V.; Cerulli, R.; Dai, C. J.; He, H. L.; Kuang, H. H.; Ma, X. H.; Sheng, X. D.; Wang, R. G.; Ye, Z. P.

The DAMA/LIBRA{phase1 and the former DAMA/NaI data (cumulative exposure 1:33 ton x yr, corresponding to 14 annual cycles) give evidence at 9.3 σ C.L. for the presence of Dark Matter (DM) particles in the galactic halo, on the basis of the exploited model independent DM annual modulation signature by using highly radiopure NaI(Tl) target. Results and comparisons will be briefly recalled. Recent analyses on possible diurnal ects and on the Earth shadowing effect (the latter holds only for some DM candidates) will be mentioned. Finally, the perspectives of the running DAMA/LIBRA-phase2 will be mentioned.

War Gaming: Space Perspective

DTIC Science & Technology

2006-01-01

2006 2. REPORT TYPE 3. DATES COVERED 00-00-2006 to 00-00-2006 4. TITLE AND SUBTITLE War Gaming : Space Perspective 5a. CONTRACT NUMBER 5b. GRANT...Edition28 ’d like to discuss WAR GAMES , no, not that movie with Mathew Broderick where the super computer asks, “Would you like to play a game ?” No, I...want to talk about modern day real war games and how we use them to better prepare ourselves for the future. As the above quote suggests by asking

Evolution of Government and Industrial Partnerships to Open the Space Frontier

NASA Technical Reports Server (NTRS)

Martin, Gary L.

2008-01-01

If the logical extension of the current exploration program is to develop self-sustaining settlements on the Moon and Mars over the next few centuries, then there is a path that takes civilization from its current one planet existence to a multi-world future. By considering the far term goal of space settlements as a desired endpoint and using the current state as a starting point, the policy drivers and potential pathways to the goal of sustainable space settlements can be explored. This paper describes a three-phased evolution of government and industrial partnerships from current day relationships to a time when there are sustainable settlements in space. Phase I details the current state government-led exploration while Phase III describes a desired endpoint of self-sufficient settlements in space. Phase II is an important transition phase, which acts as a bridge between now and the future. This paper discusses the critical evolution that must take place in two key areas to ensure a thriving future in space; space transportation and the right to use space property and resources. This paper focuses on the enabling role of government necessary to achieve United States (U.S.) goals for space exploration and open the frontier.

From Order to Chaos in Earth Satellite Orbits

NASA Astrophysics Data System (ADS)

Gkolias, Ioannis; Daquin, Jérôme; Gachet, Fabien; Rosengren, Aaron J.

2016-11-01

We consider Earth satellite orbits in the range of semimajor axes where the perturbing effects of Earth’s oblateness and lunisolar gravity are of comparable order. This range covers the medium-Earth orbits (MEO) of the Global Navigation Satellite Systems and the geosynchronous orbits (GEO) of the communication satellites. We recall a secular and quadrupolar model, based on the Milankovitch vector formulation of perturbation theory, which governs the long-term orbital evolution subject to the predominant gravitational interactions. We study the global dynamics of this two-and-a-half degrees-of-freedom Hamiltonian system by means of the fast Lyapunov indicator (FLI), used in a statistical sense. Specifically, we characterize the degree of chaoticity of the action space using angle-averaged normalized FLI maps, thereby overcoming the angle dependencies of the conventional stability maps. Emphasis is placed upon the phase-space structures near secular resonances, which are of primary importance to the space debris community. We confirm and quantify the transition from order to chaos in MEO, stemming from the critical inclinations and find that highly inclined GEO orbits are particularly unstable. Despite their reputed normality, Earth satellite orbits can possess an extraordinarily rich spectrum of dynamical behaviors and, from a mathematical perspective, have all the complications that make them very interesting candidates for testing the modern tools of chaos theory.

Quantum Optics in Phase Space

NASA Astrophysics Data System (ADS)

Schleich, Wolfgang P.

2001-04-01

Quantum Optics in Phase Space provides a concise introduction to the rapidly moving field of quantum optics from the point of view of phase space. Modern in style and didactically skillful, Quantum Optics in Phase Space prepares students for their own research by presenting detailed derivations, many illustrations and a large set of workable problems at the end of each chapter. Often, the theoretical treatments are accompanied by the corresponding experiments. An exhaustive list of references provides a guide to the literature. Quantum Optics in Phase Space also serves advanced researchers as a comprehensive reference book. Starting with an extensive review of the experiments that define quantum optics and a brief summary of the foundations of quantum mechanics the author Wolfgang P. Schleich illustrates the properties of quantum states with the help of the Wigner phase space distribution function. His description of waves ala WKB connects semi-classical phase space with the Berry phase. These semi-classical techniques provide deeper insight into the timely topics of wave packet dynamics, fractional revivals and the Talbot effect. Whereas the first half of the book deals with mechanical oscillators such as ions in a trap or atoms in a standing wave the second half addresses problems where the quantization of the radiation field is of importance. Such topics extensively discussed include optical interferometry, the atom-field interaction, quantum state preparation and measurement, entanglement, decoherence, the one-atom maser and atom optics in quantized light fields. Quantum Optics in Phase Space presents the subject of quantum optics as transparently as possible. Giving wide-ranging references, it enables students to study and solve problems with modern scientific literature. The result is a remarkably concise yet comprehensive and accessible text- and reference book - an inspiring source of information and insight for students, teachers and researchers alike.

Space Station Displays and Controls Technology Evolution

NASA Technical Reports Server (NTRS)

Blackburn, Greg C.

1990-01-01

Viewgraphs on space station displays and controls technology evolution are presented. Topics covered include: a historical perspective; major development objectives; current development activities; key technology areas; and technology evolution issues.

PERSPECTIVE VIEW LOOKING SOUTHEAST OF THE SATURN I TEST. NOTE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

PERSPECTIVE VIEW LOOKING SOUTHEAST OF THE SATURN I TEST. NOTE THE GANTRY CRANE USED TO MANEUVER ROCKETS INTO THE TEST STAND. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Reframing Children's Spaces

ERIC Educational Resources Information Center

Duncan, Sandra

2011-01-01

Like professional photographers, early childhood teachers can reframe their perspectives to create innovative and inspiring spaces for young children by concentrating on reframing two design elements: color and texture. When thinking about designing spaces for young children, one of the first considerations is the equipment and its arrangement.…

Latin-American Regional Developments in Space Technology and International Cooperation - Columbian Space Policy: An Approach to Create a National Space Agency

NASA Astrophysics Data System (ADS)

Arenales-Vergara, Oscar A.

2002-01-01

Space exploration is a great human adventure: culturally, scientifically, technologically and industrially. Since the earliest of times, civilizations have been united in their awe of, and inspiration by, the cosmos, as testified in particularly by the peoples and cultures of the Central and South American continent in pre-Columbian times. Today, space systems have become an essential tool for the scientific disciplines related to the knowledge of the universe, including our own planet and its close or its remote environment. The main objective of this research is to explain the way in which Colombia, rich in myths and secular legends connecting mankind to the universe, must in the present tackle the issue of its development of space activities. The context in which it could be carried out is also described, along with a perspective of the current state of science and technology in the space sector on a global scale. Any modern nation is concerned with its independence, whether political, economic, or intellectual. That is why we support the concept of countries in the process of development becoming actively involved in the international space scene. Indeed, having limitations in industrial and technological exchange, we feel excluded today from key fields for our tomorrow. This research thus proposes to demonstrate how in a time that can be regarded as one of the most serious crises in its history, Colombia could, in an atmosphere free from fratricidal conflicts, exploit its space matter capabilities. We do not limit our focus to the scientific field, but also consider the social, economic and cultural aspects. The results of this research delineate how Colombia could start a new optimistic phase of its development, joining the international space programs within the framework of agreements among the regional governments in Latin America.

Probing Structural and Electronic Dynamics with Ultrafast Electron Microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plemmons, DA; Suri, PK; Flannigan, DJ

In this Perspective, we provide an overview,of the field of ultrafast electron microscopy (UEM). We begin by briefly discussing the emergence of methods for probing ultrafast structural dynamics and the information that can be obtained. Distinctions are drawn between the two main types a probes for femtosecond (fs) dynamics fast electrons and X-ray photons and emphasis is placed on hour the nature of charged particles is exploited in ultrafast electron-based' experiments:. Following this, we describe the versatility enabled by the ease with which electron trajectories and velocities can be manipulated with transmission electron microscopy (TEM): hardware configurations, and we emphasizemore » how this is translated to the ability to measure scattering intensities in real, reciprocal, and energy space from presurveyed and selected rianoscale volumes. Owing to decades of ongoing research and development into TEM instrumentation combined with advances in specimen holder technology, comprehensive experiments can be conducted on a wide range of materials in various phases via in situ methods. Next, we describe the basic operating concepts, of UEM, and we emphasize that its development has led to extension of several of the formidable capabilities of TEM into the fs domain, dins increasing the accessible temporal parameter spade by several orders of magnitude. We then divide UEM studies into those conducted in real (imaging), reciprocal (diffraction), and energy (spectroscopy) spate. We begin each of these sections by providing a brief description of the basic operating principles and the types of information that can be gathered followed by descriptions of how these approaches are applied in UM, the type of specimen parameter space that can be probed, and an example of the types of dynamics that can be resolved. We conclude with an Outlook section, wherein we share our perspective on some future directions of the field pertaining to continued instrument development and application of the technique to solving seemingly intractable materials problems in addition to discovery-based research. Our goal with this Perspective is to bring the capabilities of TIEM to the-attention of materials scientists, chemists, physicists, and engineers in hopes that new,avenues of research emerge and to make clear the large parameter space that is opened by extending TEM, and the ability to readily manipulate electron trajectories and energies, into the ultrafast domain.« less

Effective increase in beam emittance by phase-space expansion using asymmetric Bragg diffraction.

PubMed

Chu, Chia-Hung; Tang, Mau-Tsu; Chang, Shih-Lin

2015-08-24

We propose an innovative method to extend the utilization of the phase space downstream of a synchrotron light source for X-ray transmission microscopy. Based on the dynamical theory of X-ray diffraction, asymmetrically cut perfect crystals are applied to reshape the position-angle-wavelength space of the light source, by which the usable phase space of the source can be magnified by over one hundred times, thereby "phase-space-matching" the source with the objective lens of the microscope. The method's validity is confirmed using SHADOW code simulations, and aberration through an optical lens such as a Fresnel zone plate is examined via matrix optics for nano-resolution X-ray images.

On the Longitudinal Morphology of Zonal Irregularity Drift Measured using Networks of GPS Scintillation Monitors

NASA Astrophysics Data System (ADS)

Carrano, C. S.; Groves, K. M.; Valladares, C. E.; Delay, S. H.

2014-12-01

A complete characterization of field-aligned ionospheric irregularities responsible for the scintillation of satellite signals includes not only their spectral properties (power spectral strength, spectral index, anisotropy ratio, and outer-scale) but also their horizontal drift velocity. From a system impacts perspective, the horizontal drift velocity is important in that it dictates the rate of signal fading and also, to an extent, the level of phase fluctuations encountered by the receiver. From a physics perspective, studying the longitudinal morphology of zonal irregularity may lead to an improved understanding of the F region dynamo and regional electrodynamics at low latitudes. The irregularity drift at low latitudes is predominantly zonal and is most commonly measured by cross-correlating observations of satellite signals made by a pair of closely-spaced antennas. The AFRL-SCINDA network operates a small number of VHF spaced-antenna systems at low latitude stations for this purpose. A far greater number of GPS scintillation monitors are operated by AFRL-SCINDA (25-30) and the Low Latitude Ionospheric Sensor Network (35-50), but the receivers are situated too far apart to monitor the drift using cross-correlation techniques. In this paper, we present an alternative approach that leverages the weak scatter scintillation theory (Rino, Radio Sci., 1979) to infer the zonal irregularity drift from single-station GPS measurements of S4, sigma-phi, and the propagation geometry alone. Unlike the spaced-receiver technique, this technique requires assumptions for the height of the scattering layer (which introduces a bias in the drift estimates) and the spectral index of the irregularities (which affects the spread of the drift estimates about the mean). Nevertheless, theory and experiment show that the ratio of sigma-phi to S4 is less sensitive to these parameters than it is to the zonal drift, and hence the zonal drift can be estimated with reasonable accuracy. In this talk, we first validate the technique using spaced VHF-antenna measurements of zonal irregularity drift from the AFRL-SCINDA network. Next, we discuss preliminary results from our investigation into the longitudinal morphology of zonal irregularity drift using the AFRL-SCINDA and LISN networks of GPS scintillation monitors.

Common View Time Transfer Using Worldwide GPS and DMA Monitor Stations

NASA Technical Reports Server (NTRS)

Reid, Wilson G.; McCaskill, Thomas B.; Oaks, Orville J.; Buisson, James A.; Warren, Hugh E.

1996-01-01

Analysis of the on-orbit Navstar clocks and the Global Positioning System (GPS) monitor station reference clocks is performed by the Naval Research Laboratory using both broadcast and postprocessed precise ephemerides. The precise ephemerides are produced by the Defense Mapping Agency (DMA) for each of the GPS space vehicles from pseudo-range measurements collected at five GPS and at five DMA monitor stations spaced around the world. Recently, DMA established an additional site co-located with the US Naval Observatory precise time site. The time reference for the new DMA site is the DoD Master Clock. Now, for the first time, it is possible to transfer time every 15 minutes via common view from the DoD Master Clock to the 11 GPS and DMA monitor stations. The estimated precision of a single common-view time transfer measurement taken over a 15-minute interval was between 1.4 and 2.7 nanoseconds. Using the measurements from all Navstar space vehicles in common view during the 15-minute interval, typically 3-7 space vehicles, improved the estimate of the precision to between 0.65 and 1.13 nanoseconds. The mean phase error obtained from closure of the time transfer around the world using the 11 monitor stations and the 25 space vehicle clocks over a period of 4 months had a magnitude of 31 picoseconds. Analysis of the low noise time transfer from the DoD Master Clock to each of the monitor stations yields not only the bias in the time of the reference clock, but also focuses attention on structure in the behaviour of the reference clock not previously seen. Furthermore, the time transfer provides a a uniformly sampled database of 15-minute measurements that make possible, for the first time, the direct and exhaustive computation of the frequency stability of the monitor station reference clocks. To lend perspective to the analysis, a summary is given of the discontinuities in phase and frequency that occurred in the reference clock at the Master Control Station during the period covered by the analysis.

Initial-value semiclassical propagators for the Wigner phase space representation: Formulation based on the interpretation of the Moyal equation as a Schrödinger equation.

PubMed

Koda, Shin-ichi

2015-12-28

We formulate various semiclassical propagators for the Wigner phase space representation from a unified point of view. As is shown in several studies, the Moyal equation, which is an equation of motion for the Wigner distribution function, can be regarded as the Schrödinger equation of an extended Hamiltonian system where its "position" and "momentum" correspond to the middle point of two points of the original phase space and the difference between them, respectively. Then we show that various phase-space semiclassical propagators can be formulated just by applying existing semiclassical propagators to the extended system. As a result, a phase space version of the Van Vleck propagator, the initial-value Van Vleck propagator, the Herman-Kluk propagator, and the thawed Gaussian approximation are obtained. In addition, we numerically compare the initial-value phase-space Van Vleck propagator, the phase-space Herman-Kluk propagator, and the classical mechanical propagation as approximation methods for the time propagation of the Wigner distribution function in terms of both accuracy and convergence speed. As a result, we find that the convergence speed of the Van Vleck propagator is far slower than others as is the case of the Hilbert space, and the Herman-Kluk propagator keeps its accuracy for a long period compared with the classical mechanical propagation while the convergence speed of the latter is faster than the former.

The State of Space Propulsion Research

NASA Technical Reports Server (NTRS)

Sackheim, R. L.; Cole, J. W.; Litchford, R. J.

2006-01-01

The current state of space propulsion research is assessed from both a historical perspective, spanning the decades since Apollo, and a forward-looking perspective, as defined by the enabling technologies required for a meaningful and sustainable human and robotic exploration program over the forthcoming decades. Previous research and technology investment approaches are examined and a course of action suggested for obtaining a more balanced portfolio of basic and applied research. The central recommendation is the establishment of a robust national Space Propulsion Research Initiative that would run parallel with systems development and include basic research activities. The basic framework and technical approach for this proposed initiative are defined and a potential implementation approach is recommended.

The role of fuel cells in NASA's space power systems

NASA Technical Reports Server (NTRS)

Been, J. F.

1979-01-01

A history of the fuel cell technology is presented and compared with NASA's increasing space power requirements. The role of fuel cells is discussed in perspective with other energy storage systems applicable for space using such criteria as type of mission, weight, reliability, costs, etc. Potential applications of space fuel cells with projected technology advances were examined.

High Frontier, The Journal for Space & Missile Professionals. Volume 3, Number 3, May 2007

DTIC Science & Technology

2007-05-01

Superiority in the 21st Century Mr. Elon Musk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27...progress new technologies. From the “Industry Perspective,” we’re fortunate to capture views from Mr. Elon Musk , CEO and CTO of Space Exploration...High Frontier Space Superiority in the 21st Century Mr. Elon Musk CEO and CTO Space

Ideas of home in palliative care research: A concept analysis.

PubMed

Tryselius, Kristina; Benzein, Eva; Persson, Carina

2018-04-23

To explore the concept of home and its' expressed spatialities in current palliative care research. Home is a central environment for living, caring, and dying. However, pure investigations of the sets of ideas linked to the concept seemed missing. Although identified as an important location, spatial perspectives expressed through the concept of home appeared unexplored. Rodgers' evolutionary concept analysis. Scientific articles published between January 2009 and September 2015. Rodgers' evolutionary concept analysis. Resulting attributes were explored from two geographically informed spatial perspectives. As main results, six attributes were identified and explored: Home as actor-capable of acting; emotional environment-something people have feelings for; place-a part of personal identity and a location; space-complex and relational spatial connections and a site for care; setting-passive background and absolute space; becoming-a fluid spatiality constantly folded. Examples of attributes and suggestions for further concept development were identified. The concept reflects various sets of ideas as well as expressing both relational and absolute perspectives of space. The most challenging for nursing research and practice seems to be investigation, operationalization, and testing the implementation of sets of ideas reflecting a relational thinking of space. © 2018 Wiley Periodicals, Inc.

Thermal protection in space technology

NASA Technical Reports Server (NTRS)

Salakhutdinov, G. M.

1982-01-01

The provision of heat protection for various elements of space flight apparata has great significance, particularly in the construction of manned transport vessels and orbital stations. A popular explanation of the methods of heat protection in rocket-space technology at the current stage as well as in perspective is provided.

De l'Espace du Dessin a Celui de l'Objet. Une Activite de Mises en Correspondances Entre des Dessins en Perspective Cavaliere et des Objets Reels.=From Drawing to Object Space. Analysis of Activities Connecting Objects with Their Perspective Drawings.

ERIC Educational Resources Information Center

Baldy, Rene

1988-01-01

The aim of this study was to gain a better understanding of the difficulties met by adults with lower levels of education on reading perspective drawings. Subjects were asked to describe verbally two perspective drawings of objects, then choose objects with defined spatial properties. Results indicated that success was an "all or…

PERSPECTIVE VIEW LOOKING NORTHEAST AT THE TEST STAND, NOTE THE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

PERSPECTIVE VIEW LOOKING NORTHEAST AT THE TEST STAND, NOTE THE SERVICE AND SUPPORT BUILDINGS TO THE LEFT AND RIGHT OF THE TEST STAND. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Space Fence PDR Concept Development Phase

NASA Astrophysics Data System (ADS)

Haines, L.; Phu, P.

2011-09-01

The Space Fence, a major Air Force acquisition program, will become the dominant low-earth orbit uncued sensor in the space surveillance network (SSN). Its primary objective is to provide a 24/7 un-cued capability to find, fix, and track small objects in low earth orbit to include emerging and evolving threats, as well as the rapidly growing population of orbital debris. Composed of up to two geographically dispersed large-scale S-band phased array radars, this new system-of-systems concept will provide comprehensive Space Situational Awareness through net-centric operations and integrated decision support. Additionally, this program will facilitate cost saving force structure changes in the SSN, specifically including the decommissioning of very-high frequency VHF Air Force Space Surveillance System (AFSSS). The Space Fence Program Office entered a Preliminary Design Review (PDR) concept development phase in January 2011 to achieve the delivery of the Initial Operational Capability (IOC) expected in FY17. Two contractors were awarded to perform preliminary system design, conduct radar performance analyses and evaluations, and develop a functional PDR radar system prototype. The key objectives for the Phase A PDR effort are to reduce Space Fence total program technical, cost, schedule, and performance risk. The overall program objective is to achieve a preliminary design that demonstrates sufficient technical and manufacturing maturity and that represents a low risk, affordable approach to meet the Space Fence Technical Requirements Document (TRD) requirements for the final development and production phase to begin in 3QFY12. This paper provides an overview of the revised Space Fence program acquisition strategy for the Phase-A PDR phase to IOC, the overall program milestones and major technical efforts. In addition, the key system trade studies and modeling/simulation efforts undertaken during the System Design Requirement (SDR) phase to address and mitigate technical challenges of the Space Fence System will also be discussed. Examples include radar system optimization studies, modeling and simulation for system performance assessment, investigation of innovative Astrodynamics algorithms for initial orbit determination and observation correlation.

de Vries liquid crystals based on a chiral 5-phenylpyrimidine benzoate core with a tri- and tetra-carbosilane backbone

NASA Astrophysics Data System (ADS)

Sreenilayam, S. P.; Rodriguez-Lojo, D.; Agra-Kooijman, D. M.; Vij, J. K.; Panov, V. P.; Panov, A.; Fisch, M. R.; Kumar, Satyendra; Stevenson, P. J.

2018-02-01

New chiral de Vries smectic liquid-crystalline compounds are designed, synthesized, and investigated for perspective applications in defect-free bistable surface-stabilized ferroelectric liquid-crystal displays. In these compounds, a 5-phenyl-pyrimidine benzoate core is terminated on one side by a tri- or tetra-carbosilane group linked through an alkoxy group and an alkyl spacer and on the opposite side terminated by a chiral 2-octanol group. The stereogenic center contains either a methyl or perfluoromethyl functional group. These compounds exhibit Iso-Sm A*-Sm C*-Sm X -Cr phases under cooling from the isotropic state. Measurements of the temperature-dependent smectic layer spacing by x-ray diffraction experiments combined with the measured apparent optical tilt angle and the birefringence reveal that Sm A* phase in these compounds is of the de Vries type. In addition, the chiral compound with a tetra-carbosilane backbone, DR277, exhibits good de Vries properties with the Sm C* phase exhibited over a wide temperature range. By varying the carbosilane end group, the de Vries properties are enhanced, that is, the layer shrinkage of ˜1.9 % for the tri-carbosilane DR276 is reduced to ˜0.9 % for tetra-carbosilane DR277 at 10°C below Sm A* to Sm C* transition temperature, TAC. For DR277, the reduction factor R ≈0.22 for T =(TAC-10 )°C is reasonably low and the apparent optical tilt angle θapp=35.1°, hence this compound is a "good de Vries smectic" LC. Therefore, synthesis of the chiral mesogen with an even higher number of carbosilane groups may lead to a further reduction or even zero-layer shrinkage exhibited at TAC with Sm C* phase extending over a wide temperature range close to the room temperature for perspective suitability in device applications. Our results for 5-phenyl-pyrimidine benzoate core-based compounds support a recently drawn conclusion by Schubert et al. [J. Mater. Chem. C 4, 8483 (2016), 10.1039/C6TC03120J] from a different compound, namely that a carbosilane backbone in chiral mesogens strongly influences the de Vries properties.

Explicit methods in extended phase space for inseparable Hamiltonian problems

NASA Astrophysics Data System (ADS)

Pihajoki, Pauli

2015-03-01

We present a method for explicit leapfrog integration of inseparable Hamiltonian systems by means of an extended phase space. A suitably defined new Hamiltonian on the extended phase space leads to equations of motion that can be numerically integrated by standard symplectic leapfrog (splitting) methods. When the leapfrog is combined with coordinate mixing transformations, the resulting algorithm shows good long term stability and error behaviour. We extend the method to non-Hamiltonian problems as well, and investigate optimal methods of projecting the extended phase space back to original dimension. Finally, we apply the methods to a Hamiltonian problem of geodesics in a curved space, and a non-Hamiltonian problem of a forced non-linear oscillator. We compare the performance of the methods to a general purpose differential equation solver LSODE, and the implicit midpoint method, a symplectic one-step method. We find the extended phase space methods to compare favorably to both for the Hamiltonian problem, and to the implicit midpoint method in the case of the non-linear oscillator.

Integrability and nonintegrability of quantum systems. II. Dynamics in quantum phase space

NASA Astrophysics Data System (ADS)

Zhang, Wei-Min; Feng, Da Hsuan; Yuan, Jian-Min

1990-12-01

Based on the concepts of integrability and nonintegrability of a quantum system presented in a previous paper [Zhang, Feng, Yuan, and Wang, Phys. Rev. A 40, 438 (1989)], a realization of the dynamics in the quantum phase space is now presented. For a quantum system with dynamical group scrG and in one of its unitary irreducible-representation carrier spaces gerhΛ, the quantum phase space is a 2MΛ-dimensional topological space, where MΛ is the quantum-dynamical degrees of freedom. This quantum phase space is isomorphic to a coset space scrG/scrH via the unitary exponential mapping of the elementary excitation operator subspace of scrg (algebra of scrG), where scrH (⊂scrG) is the maximal stability subgroup of a fixed state in gerhΛ. The phase-space representation of the system is realized on scrG/scrH, and its classical analogy can be obtained naturally. It is also shown that there is consistency between quantum and classical integrability. Finally, a general algorithm for seeking the manifestation of ``quantum chaos'' via the classical analogy is provided. Illustrations of this formulation in several important quantum systems are presented.

Phase-stepped fringe projection by rotation about the camera's perspective center.

PubMed

Huddart, Y R; Valera, J D; Weston, N J; Featherstone, T C; Moore, A J

2011-09-12

A technique to produce phase steps in a fringe projection system for shape measurement is presented. Phase steps are produced by introducing relative rotation between the object and the fringe projection probe (comprising a projector and camera) about the camera's perspective center. Relative motion of the object in the camera image can be compensated, because it is independent of the distance of the object from the camera, whilst the phase of the projected fringes is stepped due to the motion of the projector with respect to the object. The technique was validated with a static fringe projection system by moving an object on a coordinate measuring machine (CMM). The alternative approach, of rotating a lightweight and robust CMM-mounted fringe projection probe, is discussed. An experimental accuracy of approximately 1.5% of the projected fringe pitch was achieved, limited by the standard phase-stepping algorithms used rather than by the accuracy of the phase steps produced by the new technique.

Developing and Applying Synthesis Models of Emerging Space Systems

DTIC Science & Technology

2016-03-01

enables the exploration of small satellite physical trade -offs early in the conceptual design phase of the DOD space acquisition process. Early...provide trade space insights that can assist DOD space acquisition professionals in making better decisions in the conceptual design phase. More informed

Space station needs, attributes, and architectural options study. Volume 1: Missions and requirements

NASA Technical Reports Server (NTRS)

1983-01-01

Science and applications, NOAA environmental observation, commercial resource observations, commercial space processing, commercial communications, national security, technology development, and GEO servicing are addressed. Approach to time phasing of mission requirements, system sizing summary, time-phased user mission payload support, space station facility requirements, and integrated time-phased system requirements are also addressed.

Making "ethical safe space" in the translation of contested knowledge: the role of community debate in defining end-of-life decision ethics.

PubMed

Kaufert, Joseph; Schwartz, Karen; Wiebe, Rhonda; Derksen, Jim; Lutfiyya, Zana M; Richert, Dean

2013-04-01

The objectives of this article are, first, to document a unique process of research knowledge translation (KT), which the authors describe as the creation of "ethical safe space," and, second, to document the narratives of forum participants and describe their interaction in a dialogue about vulnerability, the authority of physicians, and the perspective of people with disabilities on the policy. Narrative data from qualitative interviews with individual key informants and focus groups were used to identify speakers with specific expertise on policy, disability perspectives, and bioethical issues, who were invited to participate in the Forum on Ethical Safe Space. The planning workgroup adopted a model for enabling representative participation in the public forum designed to reduce the impact of physical, sensory, financial, language, and professional status barriers. Using the transcripts and keynote speakers' printed texts, primary themes and patterns of interaction were identified reflecting the alternative perspectives. Through the development of a workshop on ethical, legal, and disability-related implications of professional policy guidelines developed by the College of Physicians and Surgeons of Manitoba, we provided a qualitative analysis of the discourse involving experts and disability community members supporting alternative positions on the impact of the policy statement, and discuss ethical, legal, and disability rights issues identified in the public debate. Contested policy and ethical frameworks for making decisions about withdrawing and withholding life supporting treatment may influence both the perspectives of palliative care providers and patients referred to palliative care facilities. An innovative model for KT using a public forum that enabled stakeholders with conflicting perspectives to engage with ethical and professional policy issues asserting the physician's authority in contested decisions involving withdrawing or withholding life-supporting treatment, was a successful way to engage stakeholders supporting alternative positions on the impact of the policy statement and to discuss ethical, legal, and disability rights issues identified in the public debate. Discussion during the forum revealed several benefits of creating ethical safe space. This model of workshop allows space for participation of stakeholders, who might not otherwise be able to interact in the same forum, to articulate their perspectives and debate with other presenters and audience members. Participants at the forum spoke of the creation of ethical safe space as a starting point for more dialogue on the issues raised by the policy statement. The forum was, therefore, seen as a potential starting point for building conversation that would facilitate revising the policy with broader consultation on its legal and ethical validity.

Asymptotically stable phase synchronization revealed by autoregressive circle maps

NASA Astrophysics Data System (ADS)

Drepper, F. R.

2000-11-01

A specially designed of nonlinear time series analysis is introduced based on phases, which are defined as polar angles in spaces spanned by a finite number of delayed coordinates. A canonical choice of the polar axis and a related implicit estimation scheme for the potentially underlying autoregressive circle map (next phase map) guarantee the invertibility of reconstructed phase space trajectories to the original coordinates. The resulting Fourier approximated, invertibility enforcing phase space map allows us to detect conditional asymptotic stability of coupled phases. This comparatively general synchronization criterion unites two existing generalizations of the old concept and can successfully be applied, e.g., to phases obtained from electrocardiogram and airflow recordings characterizing cardiorespiratory interaction.

The Ninth National Space Symposium

NASA Astrophysics Data System (ADS)

Lipskin, Beth Ann; Patterson, Sara; Brescia, David A.; Burk, Donna; Flannery, Jack; St. John, Pat; Zimkas, Chuck

Proceedings of the Ninth National Space Symposium held 13-16 April 1993 by the United States Space Foundation are presented. Presentations made at the symposium are included. Topics discussed include: Change, Challenge and Opportunity; Washington Insiders: National Space Policy and Budget Issues; Civil Space: a Vision for the Future; Space Power for an Expanded Vision; Unparalled Launch Vehicle Propulsion Capabilities; National Security Space Issues; Perspectives on the Air Force in Space; Future Technology: Space Propulsion, Earth Observation and International Cooperation; Achieving Efficient Space Transportation; the Future in Space Exploration; Kids, Parents and Teachers are into Space; and Public Congressional Forum on Space - International Space Issues.

Review of two-phase flow liquid metal MHD and turbine energy conversion concepts for space applications

NASA Technical Reports Server (NTRS)

Fabris, Gracio

1992-01-01

Two-phase energy conversion systems could be liquid metal magnetohydrodynamic (LMMHD) with no moving parts or two-phase turbines. Both of them are inherently simple and reliable devices which can operate in a wide range of temperatures. Their thermal efficiency is significantly higher than for conventional cycles due to reheat of vapor by liquid phase during the energy converting expansion. Often they can be more easily coupled to heat sources. These features make two-phase systems particularly promising for space application. Insufficient research has been done in the past. So far achieved LMMHD generator and two-phase turbine efficiencies are in the 40 to 45 percent range. However if certain fluid dynamic and design problems are resolved these efficiencies could be brought into the range of 70 percent. This would make two-phase systems extremely competitive as compared to present or other proposed conversion system for space. Accordingly, well directed research effort on potential space applications of two-phase conversion systems would be a wise investment.

Space commerce in a global economy - Comparison of international approaches to commercial space

NASA Technical Reports Server (NTRS)

Stone, Barbara A.; Kleber, Peter

1992-01-01

A historical perspective, current status, and comparison of national government/commercial space industry relationships in the United States and Europe are presented. It is noted that space technology has been developed and used primarily to meet the needs of civil and military government initiatives. Two future trends of space technology development include new space enterprises, and the national drive to achieve a more competitive global economic position.

Solar power satellite system definition study, phase 2.

NASA Technical Reports Server (NTRS)

1979-01-01

A program plan for the Solar Power Satellite Program is presented. The plan includes research, development, and evaluation phase, engineering and development and cost verification phase, prototype construction, and commercialization. Cost estimates and task requirements are given for the following technology areas: (1) solar arrays; (2) thermal engines and thermal systems; (3) power transmission (to earth); (4) large space structures; (5) materials technology; (6) system control; (7) space construction; (8) space transportation; (9) power distribution, and space environment effects.

Real-space Berry phases: Skyrmion soccer (invited)

NASA Astrophysics Data System (ADS)

Everschor-Sitte, Karin; Sitte, Matthias

2014-05-01

Berry phases occur when a system adiabatically evolves along a closed curve in parameter space. This tutorial-like article focuses on Berry phases accumulated in real space. In particular, we consider the situation where an electron traverses a smooth magnetic structure, while its magnetic moment adjusts to the local magnetization direction. Mapping the adiabatic physics to an effective problem in terms of emergent fields reveals that certain magnetic textures, skyrmions, are tailormade to study these Berry phase effects.

Real-space Berry phases: Skyrmion soccer (invited)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Everschor-Sitte, Karin, E-mail: karin@physics.utexas.edu; Sitte, Matthias

Berry phases occur when a system adiabatically evolves along a closed curve in parameter space. This tutorial-like article focuses on Berry phases accumulated in real space. In particular, we consider the situation where an electron traverses a smooth magnetic structure, while its magnetic moment adjusts to the local magnetization direction. Mapping the adiabatic physics to an effective problem in terms of emergent fields reveals that certain magnetic textures, skyrmions, are tailormade to study these Berry phase effects.

Senate Subcommittee on Space, Science, and Competitiveness Heari

NASA Image and Video Library

2018-05-16

Sen. Ted Cruz, R-Texas, chairman of the Senate Subcommittee on Space, Science, and Competitiveness speaks during a hearing titled "Examining the Future of the International Space Station: Administration Perspectives," Wednesday, May 16, 2018 in the Russell Senate Office Building on Capitol Hill in Washington. Photo Credit: (NASA/Joel Kowsky)

Senate Subcommittee on Space, Science, and Competitiveness Heari

NASA Image and Video Library

2018-05-16

NASA Inspector General Paul Martin testifies during a Senate Subcommittee on Space, Science, and Competitiveness hearing titled "Examining the Future of the International Space Station: Administration Perspectives" held on Wednesday, May 16, 2018 in the Russell Senate Office Building on Capitol Hill in Washington. Photo Credit: (NASA/Joel Kowsky)

Senate Subcommittee on Space, Science, and Competitiveness Heari

NASA Image and Video Library

2018-05-16

NASA Inspector General Paul Martin is seen during a Senate Subcommittee on Space, Science, and Competitiveness hearing titled "Examining the Future of the International Space Station: Administration Perspectives" Wednesday, May 16, 2018 in the Russell Senate Office Building on Capitol Hill in Washington. Photo Credit: (NASA/Joel Kowsky)

Automation and robotics for the Space Station - An ATAC perspective

NASA Technical Reports Server (NTRS)

Nunamaker, Robert R.

1989-01-01

The study of automation and robotics for the Space Station by the Advanced Technology Advisory Committee is surveyed. The formation of the committee and the methodology for the Space Station automation study are discussed. The committee's recommendations for automation and robotics research and development are listed.

An extensive phase space for the potential martian biosphere.

PubMed

Jones, Eriita G; Lineweaver, Charles H; Clarke, Jonathan D

2011-12-01

We present a comprehensive model of martian pressure-temperature (P-T) phase space and compare it with that of Earth. Martian P-T conditions compatible with liquid water extend to a depth of ∼310 km. We use our phase space model of Mars and of terrestrial life to estimate the depths and extent of the water on Mars that is habitable for terrestrial life. We find an extensive overlap between inhabited terrestrial phase space and martian phase space. The lower martian surface temperatures and shallower martian geotherm suggest that, if there is a hot deep biosphere on Mars, it could extend 7 times deeper than the ∼5 km depth of the hot deep terrestrial biosphere in the crust inhabited by hyperthermophilic chemolithotrophs. This corresponds to ∼3.2% of the volume of present-day Mars being potentially habitable for terrestrial-like life.

Mutually unbiased coarse-grained measurements of two or more phase-space variables

NASA Astrophysics Data System (ADS)

Paul, E. C.; Walborn, S. P.; Tasca, D. S.; Rudnicki, Łukasz

2018-05-01

Mutual unbiasedness of the eigenstates of phase-space operators—such as position and momentum, or their standard coarse-grained versions—exists only in the limiting case of infinite squeezing. In Phys. Rev. Lett. 120, 040403 (2018), 10.1103/PhysRevLett.120.040403, it was shown that mutual unbiasedness can be recovered for periodic coarse graining of these two operators. Here we investigate mutual unbiasedness of coarse-grained measurements for more than two phase-space variables. We show that mutual unbiasedness can be recovered between periodic coarse graining of any two nonparallel phase-space operators. We illustrate these results through optics experiments, using the fractional Fourier transform to prepare and measure mutually unbiased phase-space variables. The differences between two and three mutually unbiased measurements is discussed. Our results contribute to bridging the gap between continuous and discrete quantum mechanics, and they could be useful in quantum-information protocols.

Phase space manipulation in high-brightness electron beams

NASA Astrophysics Data System (ADS)

Rihaoui, Marwan M.

Electron beams have a wide range of applications, including discovery science, medicine, and industry. Electron beams can also be used to power next-generation, high-gradient electron accelerators. The performances of some of these applications could be greatly enhanced by precisely tailoring the phase space distribution of the electron beam. The goal of this dissertation is to explore some of these phase space manipulations. We especially focus on transformations capable of tailoring the beam current distribution. Specifically, we investigate a beamline exchanging phase space coordinates between the horizontal and longitudinal degrees of freedom. The key components necessary for this beamline were constructed and tested. The preliminary beamline was used as a singleshot phase space diagnostics and to produce a train of picoseconds electron bunches. We also investigate the use of multiple electron beams to control the transverse focusing. Our numerical and analytical studies are supplemented with experiments performed at the Argonne Wakefield Accelerator.

Workplace learning from a socio-cultural perspective: creating developmental space during the general practice clerkship.

PubMed

van der Zwet, J; Zwietering, P J; Teunissen, P W; van der Vleuten, C P M; Scherpbier, A J J A

2011-08-01

Workplace learning in undergraduate medical education has predominantly been studied from a cognitive perspective, despite its complex contextual characteristics, which influence medical students' learning experiences in such a way that explanation in terms of knowledge, skills, attitudes and single determinants of instructiveness is unlikely to suffice. There is also a paucity of research which, from a perspective other than the cognitive or descriptive one, investigates student learning in general practice settings, which are often characterised as powerful learning environments. In this study we took a socio-cultural perspective to clarify how students learn during a general practice clerkship and to construct a conceptual framework that captures this type of learning. Our analysis of group interviews with 44 fifth-year undergraduate medical students about their learning experiences in general practice showed that students needed developmental space to be able to learn and develop their professional identity. This space results from the intertwinement of workplace context, personal and professional interactions and emotions such as feeling respected and self-confident. These forces framed students' participation in patient consultations, conversations with supervisors about consultations and students' observation of supervisors, thereby determining the opportunities afforded to students to mind their learning. These findings resonate with other conceptual frameworks and learning theories. In order to refine our interpretation, we recommend that further research from a socio-cultural perspective should also explore other aspects of workplace learning in medical education.

Uncovering the nonadiabatic response of geosynchronous electrons to geomagnetic disturbance

USGS Publications Warehouse

Gannon, Jennifer; Elkington, Scot R.; Onsager, Terrance G.

2012-01-01

We describe an energy spectrum method for scaling electron integral flux, which is measured at a constant energy, to phase space density at a constant value of the first adiabatic invariant which removes much of the variation due to reversible adiabatic effects. Applying this method to nearly a solar cycle (1995 - 2006) of geosynchronous electron integral flux (E>2.0MeV) from the GOES satellites, we see that much of the diurnal variation in electron phase space density at constant energy can be removed by the transformation to phase space density at constant μ (4000 MeV/G). This allows us a clearer picture of underlying non-adiabatic electron population changes due to geomagnetic activity. Using scaled phase space density, we calculate the percentage of geomagnetic storms resulting in an increase, decrease or no change in geosynchronous electrons as 38%, 7%, and 55%, respectively. We also show examples of changes in the electron population that may be different than the unscaled fluxes alone suggest. These examples include sudden electron enhancements during storms which appear during the peak of negative Dst for μ-scaled phase space density, contrary to the slow increase seen during the recovery phase for unscaled phase space density for the same event.

Hierarchical phase space structure of dark matter haloes: Tidal debris, caustics, and dark matter annihilation

NASA Astrophysics Data System (ADS)

Afshordi, Niayesh; Mohayaee, Roya; Bertschinger, Edmund

2009-04-01

Most of the mass content of dark matter haloes is expected to be in the form of tidal debris. The density of debris is not constant, but rather can grow due to formation of caustics at the apocenters and pericenters of the orbit, or decay as a result of phase mixing. In the phase space, the debris assemble in a hierarchy that is truncated by the primordial temperature of dark matter. Understanding this phase structure can be of significant importance for the interpretation of many astrophysical observations and, in particular, dark matter detection experiments. With this purpose in mind, we develop a general theoretical framework to describe the hierarchical structure of the phase space of cold dark matter haloes. We do not make any assumption of spherical symmetry and/or smooth and continuous accretion. Instead, working with correlation functions in the action-angle space, we can fully account for the hierarchical structure (predicting a two-point correlation function ∝ΔJ-1.6 in the action space), as well as the primordial discreteness of the phase space. As an application, we estimate the boost to the dark matter annihilation signal due to the structure of the phase space within virial radius: the boost due to the hierarchical tidal debris is of order unity, whereas the primordial discreteness of the phase structure can boost the total annihilation signal by up to an order of magnitude. The latter is dominated by the regions beyond 20% of the virial radius, and is largest for the recently formed haloes with the least degree of phase mixing. Nevertheless, as we argue in a companion paper, the boost due to small gravitationally-bound substructure can dominate this effect at low redshifts.

Personal space regulation in childhood autism: Effects of social interaction and person's perspective.

PubMed

Candini, Michela; Giuberti, Virginia; Manattini, Alessandra; Grittani, Serenella; di Pellegrino, Giuseppe; Frassinetti, Francesca

2017-01-01

Studies in children with Typical Development (TD) and with Autism Spectrum Disorder (ASD) revealed that autism affects the personal space regulation, influencing both its size (permeability) and its changes depending on social interaction (flexibility). Here, we investigate how the nature of social interaction (Cooperative vs. Uncooperative) and the person perspective influence permeability and flexibility of interpersonal distance. Moreover, we tested whether the deficit observed in ASD children, reflects the social impairment (SI) in daily interactions. The stop-distance paradigm was used to measure the preferred distance between the participant and an unfamiliar adult (first-person perspective, Experiment 1), and between two other people (third-person perspective, Experiment 2). Interpersonal distance was measured before and after the interaction with a confederate. The Wing Subgroups Questionnaire was used to evaluate SI in everyday activities, and each ASD participant was accordingly assigned either to the lower (children with low social impairment [low-SI ASD]), or to the higher SI group (children with high social impairment [high-SI ASD]). We observed larger interpersonal distance (permeability) in both ASD groups compared to TD children. Moreover, depending on the nature of social interaction, a modulation of interpersonal distance (flexibility) was observed in TD children, both from the first- and third-person perspective. Similar findings were found in low-SI but not in high-SI ASD children, in Experiment 1. Conversely, in Experiment 2, no change was observed in both ASD groups. These findings reveal that SI severity and a person's perspective may account for the deficit observed in autism when flexibility, but not permeability, of personal space is considered. Autism Res 2017, 10: 144-154. © 2016 International Society for Autism Research, Wiley Periodicals, Inc. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

The Astrosociology of Space Colonies: Or the Social Construction of Societies in Space

NASA Astrophysics Data System (ADS)

Pass, Jim

2006-01-01

For a number of reasons, the construction of a single space colony represents a future social reality strongly likely to play itself out repeatedly as the twenty-first century advances. As early plans are considered, we must take into account that societies on Earth serve to carry out a variety of life functions and, in so doing, must meet the social needs of their citizens. While the proper engineering/construction of space habitats is necessary to ensure survivability of the inhabitants of a physical environment in space, it remains insufficient to ensure proper functioning of a social environment in space. This paper assumes that the physical environment is adequate to sustain life reliably (that is, to provide life support) and focuses instead on issues related to the sustainability of a society in space from primarily a sociological perspective. The astrosociological argument serving as a central theme here is that we must carefully consider research findings of Earth-based societies and their communities and apply the sociological lessons learned to the planning of space colonies. Moreover, the astrosociological perspective can serve to provide a formal mechanism for collaboration between social scientists and space scientists so that construction of a particular space colony proceeds based on the greatest level of understanding possible.

Discrete Dynamics Lab

NASA Astrophysics Data System (ADS)

Wuensche, Andrew

DDLab is interactive graphics software for creating, visualizing, and analyzing many aspects of Cellular Automata, Random Boolean Networks, and Discrete Dynamical Networks in general and studying their behavior, both from the time-series perspective — space-time patterns, and from the state-space perspective — attractor basins. DDLab is relevant to research, applications, and education in the fields of complexity, self-organization, emergent phenomena, chaos, collision-based computing, neural networks, content addressable memory, genetic regulatory networks, dynamical encryption, generative art and music, and the study of the abstract mathematical/physical/dynamical phenomena in their own right.

The Army and Space: Historic Perspectives on Future Prospects.

DTIC Science & Technology

1986-06-06

of the U.S. Army Command and General Staff College In partial fulfillment of the requirements for the dsgrecy MASTER OF MILITARY ART AND SCIENCE by...By__________ DDistribution/_ tAAvailnb’ility codes jAvail anId/oIr jDist Ispocial ýý 6R-tW rM.,W-MMM HO E ý- M WMM-7 MASTER OF MILITARY ART AND SCIENCE...PACU: HISTORICAL. PERSPECTIVES ON FUTURE PROSPECTS: An arialy .iy.s ,t thi. Ar ry’s early involvement in space to tind historical lessons to help guide

ARC-2009-ACD09-0143-011

NASA Image and Video Library

2009-07-17

International Space University (ISU - 2009) students participated in a Robotic Competition at NASA'A Ames Research Center, Moffett Field, Calif. This panel featured astronauts from four different space agencies with different areas of expertise and diverse perspectives.

BFV-BRST analysis of the classical and quantum q-deformations of the sl(2) algebra

NASA Astrophysics Data System (ADS)

Dayi, O. F.

1994-01-01

BFV--BRST charge for q-deformed algebras is not unique. Different constructions of it in the classical as well as in the quantum phase space for the $q$-deformed algebra sl_q(2) are discussed. Moreover, deformation of the phase space without deforming the generators of sl(2) is considered. $\\hbar$-q-deformation of the phase space is shown to yield the Witten's second deformation. To study the BFV--BRST cohomology problem when both the quantum phase space and the group are deformed, a two parameter deformation of sl(2) is proposed, and its BFV-BRST charge is given.

Space migrations: Anthropology and the humanization of space

NASA Technical Reports Server (NTRS)

Finney, Ben R.

1992-01-01

Because of its broad evolutionary perspective and its focus on both technology and culture, anthropology offers a unique view of why we are going into space and what leaving Earth will mean for humanity. In addition, anthropology could help in the humanization of space through (1) overcoming socioculture barriers to working and living in space, (2) designing societies appropriate for permanent space settlement, (3) promoting understanding among differentiated branches of humankind scattered through space, (4) deciphering the cultural systems of any extraterrestrial civilizations contacted.

Sensitivity of Space Shuttle Weight and Cost to Structure Subsystem Weights

NASA Technical Reports Server (NTRS)

Wedge, T. E.; Williamson, R. P.

1973-01-01

Quantitative relationships between changes in space shuttle weights and costs with changes in weight of various portions of space shuttle structural subsystems are investigated. These sensitivity relationships, as they apply at each of three points in the development program (preliminary design phase, detail design phase, and test/operational phase) have been established for five typical space shuttle designs, each of which was responsive to the missions in the NASA Shuttle RFP, and one design was that selected by NASA.

Scaled CMOS Reliability and Considerations for Spacecraft Systems: Bottom-Up and Top-Down Perspective

NASA Technical Reports Server (NTRS)

White, Mark

2012-01-01

New space missions will increasingly rely on more advanced technologies because of system requirements for higher performance, particularly in instruments and high-speed processing. Component-level reliability challenges with scaled CMOS in spacecraft systems from a bottom-up perspective have been presented. Fundamental Front-end and Back-end processing reliability issues with more aggressively scaled parts have been discussed. Effective thermal management from system-level to the componentlevel (top-down) is a key element in overall design of reliable systems. Thermal management in space systems must consider a wide range of issues, including thermal loading of many different components, and frequent temperature cycling of some systems. Both perspectives (top-down and bottom-up) play a large role in robust, reliable spacecraft system design.

Space Station - An integrated approach to operational logistics support

NASA Technical Reports Server (NTRS)

Hosmer, G. J.

1986-01-01

Development of an efficient and cost effective operational logistics system for the Space Station will require logistics planning early in the program's design and development phase. This paper will focus on Integrated Logistics Support (ILS) Program techniques and their application to the Space Station program design, production and deployment phases to assure the development of an effective and cost efficient operational logistics system. The paper will provide the methodology and time-phased programmatic steps required to establish a Space Station ILS Program that will provide an operational logistics system based on planned Space Station program logistics support.

Remote sensing at the NASA Kennedy Space Center: a perspective from the ground up

NASA Astrophysics Data System (ADS)

Huddleston, Lisa H.; Roeder, William P.; Morabito, David D.; D'Addario, Larry R.; Morgan, Jennifer G.; Barbré, Robert E.; Decker, Ryan K.; Geldzahler, Barry; Seibert, Mark A.; Miller, Michael J.

2014-10-01

This paper provides an overview of ground based operational remote sensing activities that enable a broad range of missions at the Eastern Range (ER), which includes the National Aeronautics and Space Administration (NASA) Kennedy Space Center (KSC) and U.S. Air Force Cape Canaveral Air Force Station (CCAFS). Many types of sensors are in use by KSC and across the ER. We examine remote sensors for winds, lightning and electric fields, precipitation and storm hazards. These sensors provide data that are used in real-time to evaluate launch commit criteria during space launches, major ground processing operations in preparation for space launches, issuing weather warnings/watches/advisories to protect over 25,000 people and facilities worth over $20 billion, and routine weather forecasts. The data from these sensors are archived to focus NASA launch vehicle design studies, to develop forecast techniques, and for incident investigation. The wind sensors include the 50-MHz and 915-MHz Doppler Radar Wind Profilers (DRWP) and the Doppler capability of the weather surveillance radars. The atmospheric electricity sensors include lightning aloft detectors, cloud-to-ground lightning detectors, and surface electric field mills. The precipitation and storm hazards sensors include weather surveillance radars. Next, we discuss a new type of remote sensor that may lead to better tracking of near-Earth asteroids versus current capabilities. The Ka Band Objects Observation and Monitoring (KaBOOM) is a phased array of three 12 meter (m) antennas being built as a technology demonstration for a future radar system that could be used to track deep-space objects such as asteroids. Transmissions in the Ka band allow for wider bandwidth than at lower frequencies, but the signals are also far more susceptible to de-correlation from turbulence in the troposphere, as well as attenuation due to water vapor, which is plentiful in the Central Florida atmosphere. If successful, KaBOOM will have served as the pathfinder for a larger and more capable instrument that will enable tracking 15 m asteroids up to 72 million kilometers (km) away, about half the distance to the Sun and five times further than we can track today. Finally, we explore the use of Site Test Interferometers (STI) as atmospheric sensors. The STI antennas continually observe signals emitted by geostationary satellites and produce measurements of the phase difference between the received signals. STIs are usually located near existing or candidate antenna array sites to statistically characterize atmospheric phase delay fluctuation effects for the site. An STI measures the fluctuations in the difference of atmospheric delay from an extraterrestrial source to two or more points on the Earth. There is a three-element STI located at the KaBOOM site at KSC.

Wavelets and the squeezed states of quantum optics

NASA Technical Reports Server (NTRS)

Defacio, B.

1992-01-01

Wavelets are new mathematical objects which act as 'designer trigonometric functions.' To obtain a wavelet, the original function space of finite energy signals is generalized to a phase-space, and the translation operator in the original space has a scale change in the new variable adjoined to the translation. Localization properties in the phase-space can be improved and unconditional bases are obtained for a broad class of function and distribution spaces. Operators in phase space are 'almost diagonal' instead of the traditional condition of being diagonal in the original function space. These wavelets are applied to the squeezed states of quantum optics. The scale change required for a quantum wavelet is shown to be a Yuen squeeze operator acting on an arbitrary density operator.

Surface Wave Propagation on a Laterally Heterogeneous Earth

NASA Astrophysics Data System (ADS)

Tromp, Jeroen

1992-01-01

Love and Rayleigh waves propagating on the surface of the Earth exhibit path, phase and amplitude anomalies as a result of the lateral heterogeneity of the mantle. In the JWKB approximation, these anomalies can be determined by tracing surface wave trajectories, and calculating phase and amplitude anomalies along them. A time- or frequency -domain JWKB analysis yields local eigenfunctions, local dispersion relations, and conservation laws for the surface wave energy. The local dispersion relations determine the surface wave trajectories, and the energy equations determine the surface wave amplitudes. On an anisotrophic Earth model the local dispersion relation and the local vertical eigenfunctions depend explicitly on the direction of the local wavevector. Apart from the usual dynamical phase, which is the integral of the local wavevector along a raypath, there is an additional variation is phase. This additional phase, which is an analogue of the Berry phase in adiabatic quantum mechanics, vanishes in a waveguide with a local vertical two-fold symmetry axis or a local horizontal mirror plane. JWKB theory breaks down in the vicinity of caustics, where neighboring rays merge and the surface wave amplitude diverges. Based upon a potential representation of the surface wave field, a uniformly valid Maslov theory can be obtained. Surface wave trajectories are determined by a system of four ordinary differential equations which define a three-dimensional manifold in four-dimensional phase space (theta,phi,k_theta,k _phi), where theta is colatitude, phi is longitude, and k_theta and k _phi are the covariant components of the wavevector. There are no caustics in phase space; it is only when the rays in phase space are projected onto configuration space (theta,phi), the mixed spaces (k_theta,phi ) and (theta,k_phi), or onto momentum space (k_theta,k _phi), that caustics occur. The essential strategy is to employ a mixed or momentum space representation of the wavefield in the vicinity of a configuration space caustic.

The making of the Chandra X-Ray Observatory: The project scientist’s perspective

PubMed Central

Weisskopf, Martin C.

2010-01-01

The history of the development of the Chandra X-Ray Observatory is reviewed from a personal perspective. This review is necessarily biased and limited by space because it attempts to cover a time span approaching five decades. PMID:20194740

Grain size dependent phase stabilities and presence of a monoclinic (Pm) phase in the morphotropic phase boundary region of (1-x)Bi(Mg1/2Ti1/2)O3-xPbTiO3 piezoceramics

NASA Astrophysics Data System (ADS)

Upadhyay, Ashutosh; Singh, Akhilesh Kumar

2015-04-01

Results of the room temperature structural studies on (1-x)Bi(Mg1/2Ti1/2)O3-xPbTiO3 ceramics using Rietveld analysis of the powder x-ray diffraction data in the composition range 0.28 ≤ x ≤ 0.45 are presented. The morphotropic phase boundary region exhibits coexistence of monoclinic (space group Pm) and tetragonal (space group P4 mm) phases in the composition range 0.33 ≤ x ≤ 0.40. The structure is nearly single phase monoclinic (space group Pm) in the composition range 0.28 ≤ x ≤ 0.32. The structure for the compositions with x ≥ 0.45 is found to be predominantly tetragonal with space group P4 mm. Rietveld refinement of the structure rules out the coexistence of rhombohedral and tetragonal phases in the morphotropic phase boundary region reported by earlier authors. The Rietveld structure analysis for the sample x = .35 calcined at various temperatures reveals that phase fraction of the coexisting phases in the morphotropic phase boundary region varies with grain size. The structural parameters of the two coexisting phases also change slightly with changing grain size.

The U.S. Space Grant College and Fellowship Program

NASA Technical Reports Server (NTRS)

Dasch, E. Julius; Schwartz, Elaine T.; Keffer, Lynne

1990-01-01

The U.S. NASA Space Grant College and Fellowship Program, congressionally mandated in 1987, consists of two phases. Phase I consisted of the designation of 21 university consortia as 'Space Grant Colleges/Consortia' which received support from NASA to conduct programs to achieve, maintain, and advance a balanced program of research capability, curriculum, and public service. Program descriptions for phase II are given. This phase is designed to broaden participation in the Space Grant Program by targeting states that currently are not as involved in NASA programs as are the states for which phase I was constructed. Under phase II, states will compete in either the Programs Grants or the Capability Enhancement Grants category. Only one proposal per state will be accepted with the state determining in which category it will compete. The amount of total award, $150,000, is the same in both categories and includes funds for university-administered fellowship programs.

Global Space Safety Regulations and Standards: The Conflicting Perspectives of the 'Merchants', the 'Guardians' and the 'Civilian' Space Agencies

NASA Astrophysics Data System (ADS)

Pelton, Joseph N.

2010-09-01

This article seek to explore the difference in viewpoint and approach to space safety that is now developing with regard to those that wish to exploit space commercially(i.e. the Merchants) versus those that see space as an extension of national defense and area of strategic interest(i.e. the Guardians), and those that pursue space as an area of civil governmental activity and oversight(i.e. the Civil Space Advocates ).1 These “actors” in the field of space and the key “definers” of space policy in future decades often see the purpose and goals related to outer space activities in fundamentally different ways. They also have quite different views as to how best to regulate and develop space safety standards and practices. With the recent shift in U.S. space policy toward commercial human flight development these issues become of even greater import to the future of space safety development and its regulation. New technological, political, defense and economic opportunities may well likely lead to increasing conflicts over best forms of management practices, appropriate regulations and standards, best ways to finance and implement new space initiatives, and even the best way to establish priorities for new projects and initiatives. This article seeks to analyze in some detail the differences in perspective and approach for all three types of actors in the field of space safety.

Space station experiment definition: Long-term cryogenic fluid storage

NASA Technical Reports Server (NTRS)

Jetley, R. L.; Scarlotti, R. D.

1987-01-01

The conceptual design of a space station Technology Development Mission (TDM) experiment to demonstrate and evaluate cryogenic fluid storage and transfer technologies is presented. The experiment will be deployed on the initial operational capability (IOC) space station for a four-year duration. It is modular in design, consisting of three phases to test the following technologies: passive thermal technologies (phase 1), fluid transfer (phase 2), and active refrigeration (phase 3). Use of existing hardware was a primary consideration throughout the design effort. A conceptual design of the experiment was completed, including configuration sketches, system schematics, equipment specifications, and space station resources and interface requirements. These requirements were entered into the NASA Space Station Mission Data Base. A program plan was developed defining a twelve-year development and flight plan. Program cost estimates are given.

Disequilibrium condensation environments in space - A frontier in thermodynamics

NASA Technical Reports Server (NTRS)

De, B. R.

1979-01-01

The thermal-disequilibrium aspect of the problem of dust-particle formation from a gas phase in an open space environment is discussed in an effort to draw attention to the space condensation environment as an interesting arena for application and extension of the ideas and formalisms of nonequilibrium thermodynamics. It is shown that quasi-steady states with a disequilibrium between the gas-phase kinetic temperature and the condensed-phase internal temperature appear to be the norm of condensation environments in space. Consideration of the case of condensation onto a bulk condensed phase indicates that these quasi-steady states may constitute Prigogine dissipative structures. It is suggested that a proper study of the process of condensation in a space environment should include any effects arising from thermal disequilibrium.

Characterization of cumulus cloud fields using trajectories in the center of gravity versus water mass phase space: 1. Cloud tracking and phase space description: CENTER OF GRAVITY VERSUS WATER MASS 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heiblum, Reuven H.; Altaratz, Orit; Koren, Ilan

We study the evolution of warm convective cloud fields using large eddy simulations of continental and trade cumulus. Individual clouds are tracked a posteriori from formation to dissipation using a 3D cloud tracking algorithm and results are presented in the phase- space of center of gravity altitude versus cloud liquid water mass (CvM space). The CvM space is shown to contain rich information on cloud field characteristics, cloud morphology, and common cloud development pathways, together facilitating a comprehensive understanding of the cloud field. In this part we show how the meteorological (thermodynamic) conditions that determine the cloud properties are projectedmore » on the CvM phase space and how changes in the initial conditions affect the clouds' trajectories in this space. This part sets the stage for a detailed microphysical analysis that will be shown in part II.« less

Transverse phase space diagnostics for ionization injection in laser plasma acceleration using permanent magnetic quadrupoles

NASA Astrophysics Data System (ADS)

Li, F.; Nie, Z.; Wu, Y. P.; Guo, B.; Zhang, X. H.; Huang, S.; Zhang, J.; Cheng, Z.; Ma, Y.; Fang, Y.; Zhang, C. J.; Wan, Y.; Xu, X. L.; Hua, J. F.; Pai, C. H.; Lu, W.; Mori, W. B.

2018-04-01

We report the transverse phase space diagnostics for electron beams generated through ionization injection in a laser-plasma accelerator. Single-shot measurements of both ultimate emittance and Twiss parameters are achieved by means of permanent magnetic quadrupole. Beams with emittance of μm rad level are obtained in a typical ionization injection scheme, and the dependence on nitrogen concentration and charge density is studied experimentally and confirmed by simulations. A key feature of the transverse phase space, matched beams with Twiss parameter α T ≃ 0, is identified according to the measurement. Numerical simulations that are in qualitative agreement with the experimental results reveal that a sufficient phase mixing induced by an overlong injection length leads to the matched phase space distribution.

Transverse phase space diagnostics for ionization injection in laser plasma acceleration using permanent magnetic quadrupoles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, F.; Nie, Z.; Wu, Y. P.

We report the transverse phase space diagnostics for electron beams generated through ionization injection in a laser-plasma accelerator. Single-shot measurements of both ultimate emittance and Twiss parameters are achieved by means of permanent magnetic quadrupole. Beams with emittance of μm rad level are obtained in a typical ionization injection scheme, and the dependence on nitrogen concentration and charge density is studied experimentally and confirmed by simulations. A key feature of the transverse phase space, matched beams with Twiss parameter α T ≃ 0, is identified according to the measurement. Lastly, numerical simulations that are in qualitative agreement with the experimentalmore » results reveal that a sufficient phase mixing induced by an overlong injection length leads to the matched phase space distribution.« less

Solid-solid phase change thermal storage application to space-suit battery pack

NASA Astrophysics Data System (ADS)

Son, Chang H.; Morehouse, Jeffrey H.

1989-01-01

High cell temperatures are seen as the primary safety problem in the Li-BCX space battery. The exothermic heat from the chemical reactions could raise the temperature of the lithium electrode above the melting temperature. Also, high temperature causes the cell efficiency to decrease. Solid-solid phase-change materials were used as a thermal storage medium to lower this battery cell temperature by utilizing their phase-change (latent heat storage) characteristics. Solid-solid phase-change materials focused on in this study are neopentyl glycol and pentaglycerine. Because of their favorable phase-change characteristics, these materials appear appropriate for space-suit battery pack use. The results of testing various materials are reported as thermophysical property values, and the space-suit battery operating temperature is discussed in terms of these property results.

Transverse phase space diagnostics for ionization injection in laser plasma acceleration using permanent magnetic quadrupoles

DOE PAGES

Li, F.; Nie, Z.; Wu, Y. P.; ...

2018-02-22

We report the transverse phase space diagnostics for electron beams generated through ionization injection in a laser-plasma accelerator. Single-shot measurements of both ultimate emittance and Twiss parameters are achieved by means of permanent magnetic quadrupole. Beams with emittance of μm rad level are obtained in a typical ionization injection scheme, and the dependence on nitrogen concentration and charge density is studied experimentally and confirmed by simulations. A key feature of the transverse phase space, matched beams with Twiss parameter α T ≃ 0, is identified according to the measurement. Lastly, numerical simulations that are in qualitative agreement with the experimentalmore » results reveal that a sufficient phase mixing induced by an overlong injection length leads to the matched phase space distribution.« less

2002 Commercial Space Transportation Lecture Series, volumes 1,2, and 3

DOT National Transportation Integrated Search

2003-04-01

This document includes three presentations which are part of the 2002 Commercial Space Transportation Lecture Series: The Early Years, AST - A Historical Perspective; Approval of Reentry Vehicles; and, Setting Insurance Requirements: Maximum Probable...

Explaining Gibbsean phase space to second year students

NASA Astrophysics Data System (ADS)

Vesely, Franz J.

2005-03-01

A new approach to teaching introductory statistical physics is presented. We recommend making extensive use of the fact that even systems with a very few degrees of freedom may display chaotic behaviour. This permits a didactic 'bottom-up' approach, starting out with toy systems whose phase space may be depicted on a screen or blackboard, then proceeding to ever higher dimensions in Gibbsean phase space.

Interplanetary Supply Chain Risk Management

NASA Technical Reports Server (NTRS)

Galluzzi, Michael C.

2018-01-01

Emphasis on KSC ground processing operations, reduced spares up-mass lift requirements and campaign-level flexible path perspective for space systems support as Regolith-based ISM is achieved by; Network modeling for sequencing space logistics and in-space logistics nodal positioning to include feedstock. Economic modeling to assess ISM 3D printing adaption and supply chain risk.

Designing Informal Learning Spaces Using Student Perspectives

ERIC Educational Resources Information Center

Riddle, Matthew David; Souter, Kay

2012-01-01

This article describes the design of informal learning spaces at an Australian university that support students in the generation of knowledge. Recent learning space design projects at La Trobe have been informed by a number of pre-existing projects, including a small research project on student use of technologies, a national project on learning…

Farm Fair Voices, Space, History, the Middle Ground and "The Future" of Rural Communities

ERIC Educational Resources Information Center

Halsey, John

2011-01-01

This article is essentially written as two linked parts. The first part considers how space, spatiality and history can contribute to understanding and "doing something about" the sustainability of rural communities. This is done by extensive reference to Soja's (1989 & 1996) space and spatial theorising and selective perspectives of…

Senate Subcommittee on Space, Science, and Competitiveness Heari

NASA Image and Video Library

2018-05-16

Sen. Bill Nelson, D-Fla., ranking member of the Senate Subcommittee on Space, Science, and Competitiveness speaks during a hearing titled "Examining the Future of the International Space Station: Administration Perspectives" held on Wednesday, May 16, 2018 in the Russell Senate Office Building on Capitol Hill in Washington. Photo Credit: (NASA/Joel Kowsky)

Tending to Change: Toward a Situated Model of Affinity Spaces

ERIC Educational Resources Information Center

Bommarito, Dan

2014-01-01

The concept of affinity spaces, a theoretical construct used to analyze literate activity from a spatial perspective, has gained popularity among scholars of literacy studies and, particularly, video-game studies. This article seeks to expand current notions of affinity spaces by identifying key assumptions that have limited researchers'…

Psychology of Learning Spaces: Impact on Teaching and Learning

ERIC Educational Resources Information Center

Granito, Vincent J.; Santana, Mary E.

2016-01-01

New research is emerging that focuses on the role the physical classroom space plays in the teaching-learning dynamic. The purpose of this exploratory research is to describe the students' and instructors' perspectives of how the classroom space and environment impact teaching and learning. Focus groups were utilized with data points coming from…

Multiplexed phase-space imaging for 3D fluorescence microscopy.

PubMed

Liu, Hsiou-Yuan; Zhong, Jingshan; Waller, Laura

2017-06-26

Optical phase-space functions describe spatial and angular information simultaneously; examples of optical phase-space functions include light fields in ray optics and Wigner functions in wave optics. Measurement of phase-space enables digital refocusing, aberration removal and 3D reconstruction. High-resolution capture of 4D phase-space datasets is, however, challenging. Previous scanning approaches are slow, light inefficient and do not achieve diffraction-limited resolution. Here, we propose a multiplexed method that solves these problems. We use a spatial light modulator (SLM) in the pupil plane of a microscope in order to sequentially pattern multiplexed coded apertures while capturing images in real space. Then, we reconstruct the 3D fluorescence distribution of our sample by solving an inverse problem via regularized least squares with a proximal accelerated gradient descent solver. We experimentally reconstruct a 101 Megavoxel 3D volume (1010×510×500µm with NA 0.4), demonstrating improved acquisition time, light throughput and resolution compared to scanning aperture methods. Our flexible patterning scheme further allows sparsity in the sample to be exploited for reduced data capture.

Phase 0 trials: an industry perspective.

PubMed

Eliopoulos, Helen; Giranda, Vincent; Carr, Robert; Tiehen, Rita; Leahy, Terri; Gordon, Gary

2008-06-15

Worldwide, cancer is a leading cause of morbidity and mortality. An increased understanding of the disease and its process has resulted in a multitude of new targeted therapies. The costs as well as time from drug discovery to market, however, remain staggeringly high and protracted, with the majority of compounds never reaching phase III. The concept of an exploratory or phase 0 trial was introduced as a mechanism to enhance and accelerate the overall process of new oncologic drug development. Performance of a phase 0 study allows researchers to better understand the pharmacokinetic and pharmacodynamic properties of compounds in human subjects before initiation of phase I trials. Data gleaned from a phase 0 trial are beneficial not only in prioritizing promising compounds but also in allowing the modification of phase I study design before initiation. To date, few researchers have taken advantage of the potential benefits of phase 0 trials. This review focuses on the purpose as well as the potential merits of phase 0 trials from the perspective of a pharmaceutical company. The review summarizes the experience of a team of researchers with ABT-888, a novel poly (ADP-ribose) polymerase agent that inhibits an enzyme critical for repairing damage to DNA, which is one of the first compounds to be investigated using the phase 0 clinical trial design.

The spatial alignment of time: Differences in alignment of deictic and sequence time along the sagittal and lateral axes.

PubMed

Walker, Esther J; Bergen, Benjamin K; Núñez, Rafael

2017-04-01

People use space in a variety of ways to structure their thoughts about time. The present report focuses on the different ways that space is employed when reasoning about deictic (past/future relationships) and sequence (earlier/later relationships) time. In the first study, we show that deictic and sequence time are aligned along the lateral axis in a manner consistent with previous work, with past and earlier events associated with left space and future and later events associated with right space. However, the alignment of time with space is different along the sagittal axis. Participants associated future events and earlier events-not later events-with the space in front of their body and past and later events with the space behind, consistent with the sagittal spatial terms (e.g., ahead, in front of) that we use to talk about deictic and sequence time. In the second study, we show that these associations between sequence time and sagittal space are sensitive to person-perspective. This suggests that the particular space-time associations observed in English speakers are influenced by a variety of different spatial properties, including spatial location and perspective. Copyright © 2016. Published by Elsevier B.V.

Triple points and phase diagrams in the extended phase space of charged Gauss-Bonnet black holes in AdS space

NASA Astrophysics Data System (ADS)

Wei, Shao-Wen; Liu, Yu-Xiao

2014-08-01

We study the triple points and phase diagrams in the extended phase space of the charged Gauss-Bonnet black holes in d-dimensional anti-de Sitter space, where the cosmological constant appears as a dynamical pressure of the system and its conjugate quantity is the thermodynamic volume of the black holes. Employing the equation of state T=T(v,P), we demonstrate that the information of the phase transition and behavior of the Gibbs free energy are potential encoded in the T-v (T-rh) line with fixed pressure P. We get the phase diagrams for the charged Gauss-Bonnet black holes with different values of the charge Q and dimension d. The result shows that the small/large black hole phase transitions appear for any d, which is reminiscent of the liquid/gas transition of a Van der Waals type. Moreover, the interesting thermodynamic phenomena, i.e., the triple points and the small/intermediate/large black hole phase transitions are observed for d=6 and Q ∈(0.1705,0.1946).

Searches for extraterrestrial life in the solar system: Status and perspectives

NASA Astrophysics Data System (ADS)

Mitrofanov, I. G.

2017-04-01

The results of space studies of the Moon and Mars are considered from the perspective of questions related to the appearance and evolution of life, as presented in the monograph of I.S. Shklovskii "Universe, Life and Razum" (Vselennaya, Zhizn', Razum [in Russian]).

Interviewing Child Witnesses: A Developmental Perspective.

ERIC Educational Resources Information Center

Saywitz, Karen; Camparo, Lorinda

1998-01-01

Reviews suggestions derived from the clinical and experimental literatures for interviewing child witnesses to abuse. Guidelines for questioning children are provided and phases of a forensic interview are outlined in a step-by-step fashion. The suggestions presented highlight a developmental perspective designed to facilitate children's memory…

Transformative occupational therapy: We are wired to be transformers.

PubMed

Dubouloz, Claire-Jehanne

2014-10-01

Transformative learning involves critical self-reflection as the motor for transforming values, beliefs, knowledge, and feelings and discovering the new meaning of daily life following a catastrophic injury or illness. Transformation has been conceptualized in various disciplines as a transcendent experience, rebirth process, and meaning-making process and within occupational therapy as a meaning perspective process. This Muriel Driver lecture explores the concept of transformation and presents the newly developed Meaning Perspectives Transformation model, constructed from research conducted with several different rehabilitation client groups. The model is characterized by three phases: trigger, changing, and outcomes. A client's critical self-reflection acts as a catalyst for moving between the phases and is represented in the model as a moment of readiness for change leading to the development of alternative ways of performing. The Meaning Perspectives Transformation model provides a tool for being an effective occupational therapist, encouraging therapists to listen closely to their clients to identify their weakening and emerging meaning perspectives and enable their occupational evolution and transformation.

Space Situational Awareness: Difficult, Expensive and Necessary

DTIC Science & Technology

2014-12-01

Senior Leader Perspective November–December 2014 Air & Space Power Journal | 6 Space Situational Awareness Difficult, Expensive—and Necessary Dr...authors thank Gen William Shelton for his thoughtful and insightful comments. Disclaimer: The views and opinions expressed or implied in the Journal ...permission. If it is reproduced, the Air and Space Power Journal requests a courtesy line. Report Documentation Page Form ApprovedOMB No. 0704-0188

Effects of different space allowances on growth performance, blood profile and pork quality in a grow-to-finish production system.

PubMed

Jang, J C; Jin, X H; Hong, J S; Kim, Y Y

2017-12-01

This experiment was conducted to evaluate the optimal space allowance on growth performance, blood profile and pork quality of growing-finishing pigs. A total of ninety crossbred pigs [(Yorkshire×Landrace)×Duroc, 30.25±1.13 kg] were allocated into three treatments (0.96: four pigs/pen, 0.96 m2/pig; 0.80: five pigs/pen, 0.80 m2/pig; 0.69: six pigs/pen, 0.69 m2/pig) in a randomized complete block design. Pigs were housed in balanced sex and had free access to feed in all phases for 14 weeks (growing phase I, growing phase II, finishing phase I, and finishing phase II). There was no statistical difference in growing phase, but a linear decrease was observed on average daily gain (ADG, p<0.01), average daily feed intake (ADFI, p<0.01), and body weight (BW, p<0.01) with decreasing space allowance in late finishing phase. On the other hand, a quadratic effect was observed on gain to feed ratio in early finishing phase (p<0.03). Consequently, overall ADG, ADFI, and final BW linearly declined in response to decreased space allowance (p<0.01). The pH of pork had no significant difference in 1 hour after slaughter, whereas there was a linear decrease in 24 h after slaughter with decreasing space allowance. Floor area allowance did not affect pork colors, but shear force linearly increased as floor space decreased (p<0.01). There was a linear increase in serum cortisol concentration on 14 week (p<0.05) with decreased space allocation. Serum IgG was linearly ameliorated as space allowance increased on 10 week (p<0.05) and 14 week (p<0.01). Data from current study indicated that stress derived from reduced space allowance deteriorates the immune system as well as growth performance of pigs, resulting in poor pork quality. Recommended adequate space allowance in a grow-to-finish production system is more than 0.80 m2/pig for maximizing growth performance and production efficiency.

Multispacecraft Observations and 3D Structure of Electromagnetic Electron Phase-Space Holes

NASA Astrophysics Data System (ADS)

Holmes, J.; Ahmadi, N.; Ergun, R.; Wilder, F. D.; Newman, D. L.; Le Contel, O.; Torbert, R. B.; Burch, J. L.

2017-12-01

Electron phase-space holes are nonlinear plasma structures characterized by a unipolar trapping potential with a radial electric field. They commonly form from beam instabilities and other turbulent processes in many plasma environments. Due to their strong fields and long lifetimes, it has been hypothesized that phase-space holes can carry energy over long distances, contribute to large-scale currents, and accelerate individual particles to high energies. With electromagnetic field measurements at high cadence and precision on more than two spacecraft, we can compare the real 3D structure of electron phase-space holes to the models suggested by Andersson et al. (2009) and Treumann and Baumjohann (2012). In this case study, we consider a train of correlated electron phase-space holes observed by all four MMS spacecraft on the dusk flank within the magnetosphere. A number of the holes appear to pass directly through the 7 km tetrahedron formation. We use this data to compute the holes' phase velocity vector relative to the background magnetic field, and quantify their internal currents and associated magnetic moments. For these weak magnetic signatures, we find that the contribution from internal E×B0 currents is comparable to the v×E effect. This study will be interesting to compare with MMS observations in the magnetotail, which are expected to capture large, semi-relativistic phase-space holes with a strong magnetic component.

General post-Minkowskian expansion and application of the phase function

NASA Astrophysics Data System (ADS)

Qin, Cheng-Gang; Shao, Cheng-Gang

2017-07-01

The phase function is a useful tool to study all observations of space missions, since it can give all the information about light propagation in a gravitational field. For the extreme accuracy of the modern space missions, a precise relativistic modeling of observations is required. So, we develop a recursive procedure enabling us to expand the phase function into a perturbative series of ascending powers of the Newtonian gravitational constant. Any n th-order perturbation of the phase function can be determined by the integral along the straight line connecting two point events. To illustrate the result, we carry out the calculation of the phase function outside a static, spherically symmetric body up to the order of G2. Then, we develop a precise relativistic model that is able to calculate the phase function and the derivatives of the phase function in the gravitational field of rotating and uniformly moving bodies. This model allows the computing of the Doppler, radio science, and astrometric observables of the space missions in the Solar System. With the development of space technology, the relativistic corrections due to the motion of a planet's spin must be considered in the high-precision space missions in the near future. As an example, we give the estimates of the relativistic corrections on the observables about the space missions TianQin and BEACON.

System technology analysis of aeroassisted orbital transfer vehicles: Moderate lift/drag (0.75-1.5). Volume 3: Cost estimates and work breakdown structure/dictionary, phase 1 and 2

NASA Technical Reports Server (NTRS)

1985-01-01

Technology payoffs of representative ground based (Phase 1) and space based (Phase 2) mid lift/drag ratio aeroassisted orbit transfer vehicles (AOTV) were assessed and prioritized. A narrative summary of the cost estimates and work breakdown structure/dictionary for both study phases is presented. Costs were estimated using the Grumman Space Programs Algorithm for Cost Estimating (SPACE) computer program and results are given for four AOTV configurations. The work breakdown structure follows the standard of the joint government/industry Space Systems Cost Analysis Group (SSCAG). A table is provided which shows cost estimates for each work breakdown structure element.

Reflective mirrors: perspective-taking in autoscopic phenomena.

PubMed

Brugger, Peter

2002-08-01

''Autoscopic phenomena refer to different illusory reduplications of one's own body and self. This article proposes a phenomenological differentiation of autoscopic reduplication into three distinct classes, i.e., autoscopic hallucinations, heautoscopy, and out-of-body experiences (OBEs). Published cases are analysed with special emphasis on the subject's point of view from which the reduplication is observed. In an autoscopic hallucination the observer's perspective is clearly body-centred, and the visual image of one's own body appears as a mirror reversal. Heautoscopy (i.e., the encounter with an alter ego or doppelgänger), is defined as a reduplication not only of bodily appearance, but also of aspects of one's psychological self. The observer's perspective may alternate between egocentric and ''alter-ego-centred''. As a consequence of the projection of bodily feelings into the doppelgänger (implying a mental rotation of one's own body along the vertical axis), original and reduplicated bodies are not mirror images of one another. This also holds for OBEs, where one's self is not reduplicated but appears to be completely dissociated from the body and observing it from a location in extracorporeal space. It is argued that perspective-taking in a spatial sense may be meaningfully related to perspective-taking in a psychological sense. The mirror in the autoscopic hallucination is a ''cognitively nonreflective mirror'' (Jean Cocteau), both spatially and psychologically. The reflective abilities of the heautoscopic mirror are better developed, yet frequent shifts in the observer's spatial perspective render the nature of psychological interactions between self and alter ego highly unpredictable. The doppelgänger may serve a transitivistic (i.e., own suffering is transferred to the alter ego) or aggressive function when this behaviour is directed against a patient. The mirror in an OBE is always reflective: It allows the self to view both space and one's psychological state from a detached but stable perspective. Spatial perspective-taking should be more thoroughly assessed in patients reporting autoscopic phenomena. By elucidating the interactions between spatial phenomenology and psychological function, we may gain important insights into the relationships between the self, its body, and phenomenal space.

Cassava; African perspective on space agriculture

NASA Astrophysics Data System (ADS)

Katayama, Naomi; Njemanze, Philip; Nweke, Felix; Space Agriculture Task Force, J.; Katayama, Naomi; Yamashita, Masamichi

Looking on African perspective in space agriculture may contribute to increase diversity, and enforce robustness for advanced life support capability. Cassava, Manihot esculentaand, is one of major crop in Africa, and could be a candidate of space food materials. Since resource is limited for space agriculture in many aspects, crop yield should be high in efficiency, and robust as well. The efficiency is measured by farming space and time. Harvest yield of cassava is about 41 MJ/ m2 (70 ton/ha) after 11 months of farming. Among rice, wheat, potato, and sweet potato, cassava is ranked to the first place (40 m2 ) in terms of farming area required to supply energy of 5 MJ/day, which is recommended for one person. Production of cassava could be made under poor condition, such as acidic soil, shortage of fertilizer, draught. Laterite, similar to Martian regolith. Propagation made by stem cutting is an advantage of cassava in space agriculture avoiding entomophilous or anemophilous process to pollinate. Feature of crop storage capability is additional factor that determines the efficiency in the whole process of agriculture. Cassava root tuber can be left in soil until its consumption. Cassava might be an African contribution to space agriculture.

3D imaging of translucent media with a plenoptic sensor based on phase space optics

NASA Astrophysics Data System (ADS)

Zhang, Xuanzhe; Shu, Bohong; Du, Shaojun

2015-05-01

Traditional stereo imaging technology is not working for dynamical translucent media, because there are no obvious characteristic patterns on it and it's not allowed using multi-cameras in most cases, while phase space optics can solve the problem, extracting depth information directly from "space-spatial frequency" distribution of the target obtained by plenoptic sensor with single lens. This paper discussed the presentation of depth information in phase space data, and calculating algorithms with different transparency. A 3D imaging example of waterfall was given at last.

Cycle-Averaged Phase-Space States for the Harmonic and the Morse Oscillators, and the Corresponding Uncertainty Relations

ERIC Educational Resources Information Center

Nicolaides, Cleanthes A.; Constantoudis, Vasilios

2009-01-01

In Planck's model of the harmonic oscillator (HO) a century ago, both the energy and the phase space were quantized according to epsilon[subscript n] = nhv, n = 0, 1, 2..., and [double integral]dp[subscript x] dx = h. By referring to just these two relations, we show how the adoption of "cycle-averaged phase-space states" (CAPSSs) leads to the…

Optical sectioning for optical scanning holography using phase-space filtering with Wigner distribution functions.

PubMed

Kim, Hwi; Min, Sung-Wook; Lee, Byoungho; Poon, Ting-Chung

2008-07-01

We propose a novel optical sectioning method for optical scanning holography, which is performed in phase space by using Wigner distribution functions together with the fractional Fourier transform. The principle of phase-space optical sectioning for one-dimensional signals, such as slit objects, and two-dimensional signals, such as rectangular objects, is first discussed. Computer simulation results are then presented to substantiate the proposed idea.

Analysis of remote operating systems for space-based servicing operations, volume 1

NASA Technical Reports Server (NTRS)

1985-01-01

A two phase study was conducted to analyze and develop the requirements for remote operating systems as applied to space based operations for the servicing, maintenance, and repair of satellites. Phase one consisted of the development of servicing requirements to establish design criteria for remote operating systems. Phase two defined preferred system concepts and development plans which met the requirements established in phase one. The specific tasks in phase two were to: (1) identify desirable operational and conceptual approaches for selected mission scenarios; (2) examine the potential impact of remote operating systems incorporated into the design of the space station; (3) address remote operating systems design issues, such as mobility, which are effected by the space station configuration; and (4) define the programmatic approaches for technology development, testing, simulation, and flight demonstration.

Understanding the International Space Station Crew Perspective following Long-Duration Missions through Data Analytics & Visualization of Crew Feedback

NASA Technical Reports Server (NTRS)

Bryant, Cody; Meza, David; Schoenstein, Nicole; Schuh, Susan

2017-01-01

The International Space Station (ISS) first became a home and research laboratory for NASA and International Partner crewmembers over 16 years ago. Each ISS mission lasts approximately 6 months and consists of three to six crewmembers. After returning to Earth, most crewmembers participate in an extensive series of 30+ debriefs intended to further understand life onboard ISS and allow crews to reflect on their experiences. Examples of debrief data collected include ISS crew feedback about sleep, dining, payload science, scheduling and time planning, health & safety, and maintenance. The Flight Crew Integration (FCI) Operational Habitability (OpsHab) team, based at Johnson Space Center (JSC), is a small group of Human Factors engineers and one stenographer that has worked collaboratively with the NASA Astronaut office and ISS Program to collect, maintain, disseminate and analyze this data. The database provides an exceptional and unique resource for understanding the "crew perspective" on long duration space missions. Data is formatted and categorized to allow for ease of search, reporting, and ultimately trending, in order to understand lessons learned, recurring issues and efficiencies gained over time. Recently, the FCI OpsHab team began collaborating with the NASA JSC Knowledge Management team to provide analytical analysis and visualization of these over 75,000 crew comments in order to better ascertain the crew's perspective on long duration spaceflight and gain insight on changes over time. In this initial phase of study, a text mining framework was used to cluster similar comments and develop measures of similarity useful for identifying relevant topics affecting crew health or performance, locating similar comments when a particular issue or item of operational interest is identified, and providing search capabilities to identify information pertinent to future spaceflight systems and processes for things like procedure development and training. In addition, the comments were scored for sentiment using a polarity scoring algorithm to identify both positive and negative comments for particular groups and clusters, allowing the team to make analytically informed decisions regarding future hardware and operating procedures. The use of polarity scoring with time series analysis was used to provide insight into how crew health and habitability is changing throughout various spaceflight increments or the station lifecycle as a whole. Finally, a visualization framework was developed to address the needs of the end users to search for and analyze comments by user, category or mission. This paper will discuss how the use of an analytical framework in conjunction with the current human interface, improved the understanding of crew perspective and shortened the time for analysis allowing for more informed decisions and rapid development of improvements. These methods are significantly optimizing the way that this valuable data can be assessed and applied to current and future spaceflight design and development. This collaboration allows the FCI OpsHab team to effectively analyze and share data in a more automated and timely fashion. Trends are no longer derived manually and can be illustrated effectively and accurately with these evolving techniques to an ever growing group of human spaceflight end users.

Quantization of geometric phase with integer and fractional topological characterization in a quantum Ising chain with long-range interaction.

PubMed

Sarkar, Sujit

2018-04-12

An attempt is made to study and understand the behavior of quantization of geometric phase of a quantum Ising chain with long range interaction. We show the existence of integer and fractional topological characterization for this model Hamiltonian with different quantization condition and also the different quantized value of geometric phase. The quantum critical lines behave differently from the perspective of topological characterization. The results of duality and its relation to the topological quantization is presented here. The symmetry study for this model Hamiltonian is also presented. Our results indicate that the Zak phase is not the proper physical parameter to describe the topological characterization of system with long range interaction. We also present quite a few exact solutions with physical explanation. Finally we present the relation between duality, symmetry and topological characterization. Our work provides a new perspective on topological quantization.

Language Competence in Movement: A Child's Perspective

ERIC Educational Resources Information Center

Laursen, Helle Pia; Mogensen, Naja Dahlstrup

2016-01-01

This article examines how, in a multilingual perspective, language competence is experienced, talked about and practiced by language users themselves. By viewing children as active co-creators of the spaces in which language is used, this article contributes to a research tradition in which focus is shifted from viewing the individual's language…

International Doctoral Students' Becoming: A Dialogic Perspective

ERIC Educational Resources Information Center

Xu, Linlin; Grant, Barbara

2017-01-01

This paper takes up Bakhtin's dialogic perspective to explore the becoming of one Chinese international doctoral student's voices. We investigate how a single participant (from a wider study) assimilates the most transformative but "alien" voice of critical thinking in her supervision space by participating in dialogues with key speaking…

Theorising Participation in Urban Regeneration Partnerships: An Adult Education Perspective

ERIC Educational Resources Information Center

Galvin, Martin; Mooney Simmie, Geraldine

2017-01-01

While the policy approach in Urban Regeneration Partnership tends to be viewed as participatory governance using an urban studies lens, this article posits an alternative theorisation that takes an adult education perspective. We draw from Lefebvre's notion of "space", Engeström's "Cultural Historical Activity Theory" and…

Article Screening System

NASA Technical Reports Server (NTRS)

Fernandez, Kenneth R. (Inventor)

2004-01-01

During the last ten years patents directed to luggage scanning apparatus began to appear in the patent art. Absent from the variety of approaches in the art is stereoscopic imaging that entails exposing two or more images of the same object, each taken from a slightly different perspective. If the perspectives are too different, that is. if there is too much separation of the X-ray exposures, the image will look flat. Yet with a slight separation, a stereo separation, interference occurs. Herein a system is provided for the production of stereo pairs. One perspective, a left or a right perspective angle, is first established. Next, the other perspective angle is computed. Using these left and right perspectives the X-ray sources can then be spaced away from each other.

Space Environments and Effects Concept: Transitioning Research to Operations and Applications

NASA Technical Reports Server (NTRS)

Edwards, David L.; Spann, James; Burns, Howard D.; Schumacher, Dan

2012-01-01

The National Aeronautics and Space Administration (NASA) is embarking on a course to expand human presence beyond Low Earth Orbit (LEO) while expanding its mission to explore the solar system. Destinations such as Near Earth Asteroids (NEA), Mars and its moons, and the outer planets are but a few of the mission targets. NASA has established numerous offices specializing in specific space environments disciplines that will serve to enable these missions. To complement these existing discipline offices, a concept focusing on the development of space environment and effects application is presented. This includes space climate, space weather, and natural and induced space environments. This space environment and effects application is composed of 4 topic areas; characterization and modeling, engineering effects, prediction and operation, and mitigation and avoidance. These topic areas are briefly described below. Characterization and modeling of space environments will primarily focus on utilization during Program mission concept, planning, and design phases. Engineering effects includes materials testing and flight experiments producing data to be used in mission planning and design phases. Prediction and operation pulls data from existing sources into decision-making tools and empirical data sets to be used during the operational phase of a mission. Mitigation and avoidance will develop techniques and strategies used in the design and operations phases of the mission. The goal of this space environment and effects application is to develop decision-making tools and engineering products to support the mission phases of mission concept through operations by focusing on transitioning research to operations. Products generated by this space environments and effects application are suitable for use in anomaly investigations. This paper will outline the four topic areas, describe the need, and discuss an organizational structure for this space environments and effects application.

Independent-Cluster Parametrizations of Wave Functions in Model Field Theories III. The Coupled-Cluster Phase Spaces and Their Geometrical Structure

NASA Astrophysics Data System (ADS)

Arponen, J. S.; Bishop, R. F.

1993-11-01

In this third paper of a series we study the structure of the phase spaces of the independent-cluster methods. These phase spaces are classical symplectic manifolds which provide faithful descriptions of the quantum mechanical pure states of an arbitrary system. They are "superspaces" in the sense that the full physical many-body or field-theoretic system is described by a point of the space, in contrast to "ordinary" spaces for which the state of the physical system is described rather by the whole space itself. We focus attention on the normal and extended coupled-cluster methods (NCCM and ECCM). Both methods provide parametrizations of the Hilbert space which take into account in increasing degrees of completeness the connectivity properties of the associated perturbative diagram structure. This corresponds to an increasing incorporation of locality into the description of the quantum system. As a result the degree of nonlinearity increases in the dynamical equations that govern the temporal evolution and determine the equilibrium state. Because of the nonlinearity, the structure of the manifold becomes geometrically complicated. We analyse the neighbourhood of the ground state of the one-mode anharmonic bosonic field theory and derive the nonlinear expansion beyond the linear response regime. The expansion is given in terms of normal-mode amplitudes, which provide the best local coordinate system close to the ground state. We generalize the treatment to other nonequilibrium states by considering the similarly defined normal coordinates around the corresponding phase space point. It is pointed out that the coupled-cluster method (CCM) maps display such features as (an)holonomy, or geometric phase. For example, a physical state may be represented by a number of different points on the CCM manifold. For this reason the whole phase spaces in the NCCM or ECCM cannot be covered by a single chart. To account for this non-Euclidean nature we introduce a suitable pseudo-Riemannian metric structure which is compatible with an important subset of all canonical transformations. It is then shown that the phase space of the configuration-interaction method is flat, namely the complex Euclidean space; that the NCCM manifold has zero curvature even though its Reimann tensor does not vanish; and that the ECCM manifold is intrinsically curved. It is pointed out that with the present metrization many of the dimensions of the ECCM phase space are effectively compactified and that the overall topological structure of the space is related to the distribution of the zeros of the Bargmann wave function.

FROM ORDER TO CHAOS IN EARTH SATELLITE ORBITS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gkolias, Ioannis; Gachet, Fabien; Daquin, Jérôme

We consider Earth satellite orbits in the range of semimajor axes where the perturbing effects of Earth’s oblateness and lunisolar gravity are of comparable order. This range covers the medium-Earth orbits (MEO) of the Global Navigation Satellite Systems and the geosynchronous orbits (GEO) of the communication satellites. We recall a secular and quadrupolar model, based on the Milankovitch vector formulation of perturbation theory, which governs the long-term orbital evolution subject to the predominant gravitational interactions. We study the global dynamics of this two-and-a-half degrees-of-freedom Hamiltonian system by means of the fast Lyapunov indicator (FLI), used in a statistical sense. Specifically,more » we characterize the degree of chaoticity of the action space using angle-averaged normalized FLI maps, thereby overcoming the angle dependencies of the conventional stability maps. Emphasis is placed upon the phase-space structures near secular resonances, which are of primary importance to the space debris community. We confirm and quantify the transition from order to chaos in MEO, stemming from the critical inclinations and find that highly inclined GEO orbits are particularly unstable. Despite their reputed normality, Earth satellite orbits can possess an extraordinarily rich spectrum of dynamical behaviors and, from a mathematical perspective, have all the complications that make them very interesting candidates for testing the modern tools of chaos theory.« less

A Modified Kinematic Model of Neutral and Ionized Gas in Galactic Center

NASA Astrophysics Data System (ADS)

Krishnarao, Dhanesh; Benjamin, Robert A.; Haffner, L. Matthew

2018-01-01

Gas near the center of the Milky Way is very complex across all phases (cold, warm, neutral, ionized, atomic, molecular, etc.) and shows strong observational evidence for warping, lopsided orientations and strongly non-circular kinematics. Historically, the kinematic complexities were modeled with many discrete features involved with expulsive phenomena near Galactic Center. However, much of the observed emission can be explained with a single unified and smooth density structure when geometrical and perspective effects are accounted for. Here we present a new model for a tilted, elliptical disk of gas within the inner 2 kpc of Galactic center based on the series of models following Burton & Liszt (1978 - 1992, Papers I- V). Machine learning techniques such as the Histogram of Oriented Gradients image correlation statistic are used to optimize the geometry and kinematics of neutral and ionized gas in 3D observational space (position,position, velocity). The model successfully predicts emission from neutral gas as seen by HI (Hi4Pi) and explains anomalous ionized gas features in H-Alpha emission (Wisconsin H-Alpha Mapper) and UV absorption lines (Hubble Space Telescope - Space Telescope Imaging Spectrograph). The modeled distribution of this tilted gas disk along with its kinematics of elliptical x1 orbits can reveal new insight about the Galactic Bar, star formation, and high-velocity gas near Galactic Center and its relation with the Fermi Bubble.

NASA's First Atrial Fibrillation Case - Deke Slayton

NASA Technical Reports Server (NTRS)

Tarver, William J.

2010-01-01

Concerns about heart dysrhythmia have been present since the earliest days of the US manned space program. While information about an astronaut's health is general kept private, one of the original seven American astronaut's health status was played out in a very public forum. Donald "Deke" Slayton was removed from the second manned space flight when it was discovered he had idiopathic atrial fibrillation. Referencing the original medical documents, details of how this was discovered and managed from the medical perspective will be reviewed. This is NASA's first heart dysrhythmia case in an astronaut and it proves quite interesting when placed in historic perspective.

The connotation interpretation of high-efficiency agriculture under the perspective of a combined agriculture with tourism

NASA Astrophysics Data System (ADS)

Zhou, Jie; Zhang, Feng-tai; Gai, Yuan-jin; Deng, Bao-kun; Shao, Ji-xin; An, You-zhi

2017-08-01

Through literature review, the article points out that the existing of the high-efficiency agriculture definition is limited to results oriented thinking, apparently lack of process oriented thinking. Combined with the connotation of fusion agriculture and tourism, respectively from the time and space utilization efficiency, cash cost, elements of input and output form, etc, gives high-efficiency agriculture a new connotation. Under the perspective of a combined agriculture with tourism, efficient use of time and space, low realized cost, less costs and output form of agriculture, this is highly effective agriculture.

Space Station in the 21st century - A social perspective

NASA Technical Reports Server (NTRS)

Bluth, B. J.

1986-01-01

A human factors and sociological consideration of Space Station crew facilities and interactions is presented which attempts to place the experiences of astronaut communities in the larger context of late 20th century industrial, economic, and cultural trends. Attention is given to the relationship of Space Station communities to 'Information Society' - related historical developments.

Senate Subcommittee on Space, Science, and Competitiveness Heari

NASA Image and Video Library

2018-05-16

NASA Associate Administrator for the Human Exploration and Operations Mission Directorate William Gerstenmaier testifies during a Senate Subcommittee on Space, Science, and Competitiveness hearing titled "Examining the Future of the International Space Station: Administration Perspectives" held on Wednesday, May 16, 2018 in the Russell Senate Office Building on Capitol Hill in Washington. Photo Credit: (NASA/Joel Kowsky)

Biofilms On Orbit and On Earth: Current Methods, Future Needs

NASA Technical Reports Server (NTRS)

Vega, Leticia

2013-01-01

Biofilms have played a significant role on the effectiveness of life support hardware on the Space Shuttle and International Space Station (ISS). This presentation will discuss how biofilms impact flight hardware, how on orbit biofilms are analyzed from an engineering and research perspective, and future needs to analyze and utilize biofilms for long duration, deep space missions.

Changing Our Perspective on Space: Place Mathematics as a Human Endeavour

ERIC Educational Resources Information Center

Owens, Kay

2010-01-01

This paper collates some of the systematic ways that different cultural groups refer to space. In some cases, space is more strongly identified in terms of place than in school Indo-European mathematics approaches. The affinity to place does not reduce the efficient, abstract, mathematical system behind the reference but it does strengthen its…

Grassmann phase space theory and the Jaynes–Cummings model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dalton, B.J., E-mail: bdalton@swin.edu.au; Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne, Victoria 3122; Garraway, B.M.

2013-07-15

The Jaynes–Cummings model of a two-level atom in a single mode cavity is of fundamental importance both in quantum optics and in quantum physics generally, involving the interaction of two simple quantum systems—one fermionic system (the TLA), the other bosonic (the cavity mode). Depending on the initial conditions a variety of interesting effects occur, ranging from ongoing oscillations of the atomic population difference at the Rabi frequency when the atom is excited and the cavity is in an n-photon Fock state, to collapses and revivals of these oscillations starting with the atom unexcited and the cavity mode in a coherentmore » state. The observation of revivals for Rydberg atoms in a high-Q microwave cavity is key experimental evidence for quantisation of the EM field. Theoretical treatments of the Jaynes–Cummings model based on expanding the state vector in terms of products of atomic and n-photon states and deriving coupled equations for the amplitudes are a well-known and simple method for determining the effects. In quantum optics however, the behaviour of the bosonic quantum EM field is often treated using phase space methods, where the bosonic mode annihilation and creation operators are represented by c-number phase space variables, with the density operator represented by a distribution function of these variables. Fokker–Planck equations for the distribution function are obtained, and either used directly to determine quantities of experimental interest or used to develop c-number Langevin equations for stochastic versions of the phase space variables from which experimental quantities are obtained as stochastic averages. Phase space methods have also been developed to include atomic systems, with the atomic spin operators being represented by c-number phase space variables, and distribution functions involving these variables and those for any bosonic modes being shown to satisfy Fokker–Planck equations from which c-number Langevin equations are often developed. However, atomic spin operators satisfy the standard angular momentum commutation rules rather than the commutation rules for bosonic annihilation and creation operators, and are in fact second order combinations of fermionic annihilation and creation operators. Though phase space methods in which the fermionic operators are represented directly by c-number phase space variables have not been successful, the anti-commutation rules for these operators suggest the possibility of using Grassmann variables—which have similar anti-commutation properties. However, in spite of the seminal work by Cahill and Glauber and a few applications, the use of phase space methods in quantum optics to treat fermionic systems by representing fermionic annihilation and creation operators directly by Grassmann phase space variables is rather rare. This paper shows that phase space methods using a positive P type distribution function involving both c-number variables (for the cavity mode) and Grassmann variables (for the TLA) can be used to treat the Jaynes–Cummings model. Although it is a Grassmann function, the distribution function is equivalent to six c-number functions of the two bosonic variables. Experimental quantities are given as bosonic phase space integrals involving the six functions. A Fokker–Planck equation involving both left and right Grassmann differentiations can be obtained for the distribution function, and is equivalent to six coupled equations for the six c-number functions. The approach used involves choosing the canonical form of the (non-unique) positive P distribution function, in which the correspondence rules for the bosonic operators are non-standard and hence the Fokker–Planck equation is also unusual. Initial conditions, such as those above for initially uncorrelated states, are discussed and used to determine the initial distribution function. Transformations to new bosonic variables rotating at the cavity frequency enable the six coupled equations for the new c-number functions–that are also equivalent to the canonical Grassmann distribution function–to be solved analytically, based on an ansatz from an earlier paper by Stenholm. It is then shown that the distribution function is exactly the same as that determined from the well-known solution based on coupled amplitude equations. In quantum–atom optics theories for many atom bosonic and fermionic systems are needed. With large atom numbers, treatments must often take into account many quantum modes—especially for fermions. Generalisations of phase space distribution functions of phase space variables for a few modes to phase space distribution functionals of field functions (which represent the field operators, c-number fields for bosons, Grassmann fields for fermions) are now being developed for large systems. For the fermionic case, the treatment of the simple two mode problem represented by the Jaynes–Cummings model is a useful test case for the future development of phase space Grassmann distribution functional methods for fermionic applications in quantum–atom optics. -- Highlights: •Novel phase space theory of the Jaynes–Cummings model using Grassmann variables. •Fokker–Planck equations solved analytically. •Results agree with the standard quantum optics treatment. •Grassmann phase space theory applicable to fermion many-body problems.« less

Direct and accelerated parameter mapping using the unscented Kalman filter.

PubMed

Zhao, Li; Feng, Xue; Meyer, Craig H

2016-05-01

To accelerate parameter mapping using a new paradigm that combines image reconstruction and model regression as a parameter state-tracking problem. In T2 mapping, the T2 map is first encoded in parameter space by multi-TE measurements and then encoded by Fourier transformation with readout/phase encoding gradients. Using a state transition function and a measurement function, the unscented Kalman filter can describe T2 mapping as a dynamic system and directly estimate the T2 map from the k-space data. The proposed method was validated with a numerical brain phantom and volunteer experiments with a multiple-contrast spin echo sequence. Its performance was compared with a conjugate-gradient nonlinear inversion method at undersampling factors of 2 to 8. An accelerated pulse sequence was developed based on this method to achieve prospective undersampling. Compared with the nonlinear inversion reconstruction, the proposed method had higher precision, improved structural similarity and reduced normalized root mean squared error, with acceleration factors up to 8 in numerical phantom and volunteer studies. This work describes a new perspective on parameter mapping by state tracking. The unscented Kalman filter provides a highly accelerated and efficient paradigm for T2 mapping. © 2015 Wiley Periodicals, Inc.

Marriages of mathematics and physics: A challenge for biology.

PubMed

Islami, Arezoo; Longo, Giuseppe

2017-12-01

The human attempts to access, measure and organize physical phenomena have led to a manifold construction of mathematical and physical spaces. We will survey the evolution of geometries from Euclid to the Algebraic Geometry of the 20th century. The role of Persian/Arabic Algebra in this transition and its Western symbolic development is emphasized. In this relation, we will also discuss changes in the ontological attitudes toward mathematics and its applications. Historically, the encounter of geometric and algebraic perspectives enriched the mathematical practices and their foundations. Yet, the collapse of Euclidean certitudes, of over 2300 years, and the crisis in the mathematical analysis of the 19th century, led to the exclusion of "geometric judgments" from the foundations of Mathematics. After the success and the limits of the logico-formal analysis, it is necessary to broaden our foundational tools and re-examine the interactions with natural sciences. In particular, the way the geometric and algebraic approaches organize knowledge is analyzed as a cross-disciplinary and cross-cultural issue and will be examined in Mathematical Physics and Biology. We finally discuss how the current notions of mathematical (phase) "space" should be revisited for the purposes of life sciences. Copyright © 2017. Published by Elsevier Ltd.

Near-critical fluids under microgravity : status of the eseme program and perspectives for the iss

NASA Astrophysics Data System (ADS)

Beysens, D.; Garrabos, Y.

2001-03-01

Started 16 years ago, the ESEME program has led to a number of important findings. We note a simple and unified view of phase transitions, which has been applied to the development of biological patterns, and a very fast thermalization mode that we coined the "piston effect". This effect has been applied to control the cryogenic reservoirs of the Ariane 5 rocket. All these findings have been obtained thanks to the good coordination of the ESA and CNES space facilities and the construction of high technology experimental modules. The future of the program is linked to the CNES DECLIC facility and the ESA Fluid Science Laboratory (FSL). DECLIC has been designed to increase the temperature regulation above the critical point of water (550 K) so as to investigate chemical reactions under conditions of supercritical water, and in relation to the promising applications of waste treatment by supercritical oxidation. Thanks to the construction of a special vibrational Experiment Container for FSL, the thermal and mechanical behavior of fluids under forced vibration can be investigated. The results of such studies will help to estimate the effect of g-jitter on fluids, and control gases and liquids in space.

Full complex spatial filtering with a phase mostly DMD. [Deformable Mirror Device

NASA Technical Reports Server (NTRS)

Florence, James M.; Juday, Richard D.

1991-01-01

A new technique for implementing fully complex spatial filters with a phase mostly deformable mirror device (DMD) light modulator is described. The technique combines two or more phase-modulating flexure-beam mirror elements into a single macro-pixel. By manipulating the relative phases of the individual sub-pixels within the macro-pixel, the amplitude and the phase can be independently set for this filtering element. The combination of DMD sub-pixels into a macro-pixel is accomplished by adjusting the optical system resolution, thereby trading off system space bandwidth product for increased filtering flexibility. Volume in the larger dimensioned space, space bandwidth-complex axes count, is conserved. Experimental results are presented mapping out the coupled amplitude and phase characteristics of the individual flexure-beam DMD elements and demonstrating the independent control of amplitude and phase in a combined macro-pixel. This technique is generally applicable for implementation with any type of phase modulating light modulator.

Hearing on Space Situational Awareness:

NASA Image and Video Library

2018-06-22

NASA Administrator Jim Bridenstine testifies before the House Subcommittee on Strategic Forces during a hearing on Space Situational Awareness: Whole of Government Perspectives on Roles and Responsibilities, Friday, June 22, 2018 at the Rayburn House Office Building in Washington. Photo Credit: (NASA/Bill Ingalls)

Transverse Phase Space Reconstruction and Emittance Measurement of Intense Electron Beams using a Tomography Technique

NASA Astrophysics Data System (ADS)

Stratakis, D.; Kishek, R. A.; Li, H.; Bernal, S.; Walter, M.; Tobin, J.; Quinn, B.; Reiser, M.; O'Shea, P. G.

2006-11-01

Tomography is the technique of reconstructing an image from its projections. It is widely used in the medical community to observe the interior of the human body by processing multiple x-ray images taken at different angles, A few pioneering researchers have adapted tomography to reconstruct detailed phase space maps of charged particle beams. Some questions arise regarding the limitations of tomography technique for space charge dominated beams. For instance is the linear space charge force a valid approximation? Does tomography equally reproduce phase space for complex, experimentally observed, initial particle distributions? Does tomography make any assumptions about the initial distribution? This study explores the use of accurate modeling with the particle-in-cell code WARP to address these questions, using a wide range of different initial distributions in the code. The study also includes a number of experimental results on tomographic phase space mapping performed on the University of Maryland Electron Ring (UMER).

Bio-Adaption between Magnesium Alloy Stent and the Blood Vessel: A Review.

PubMed

Ma, Jun; Zhao, Nan; Betts, Lexxus; Zhu, Donghui

2016-09-01

Biodegradable magnesium (Mg) alloy stents are the most promising next generation of bio-absorbable stents. In this article, we summarized the progresses on the in vitro studies, animal testing and clinical trials of biodegradable Mg alloy stents in the past decades. These exciting findings led us to propose the importance of the concept "bio-adaption" between the Mg alloy stent and the local tissue microenvironment after implantation. The healing responses of stented blood vessel can be generally described in three overlapping phases: inflammation, granulation and remodeling. The ideal bio-adaption of the Mg alloy stent, once implanted into the blood vessel, needs to be a reasonable function of the time and the space/dimension. First, a very slow degeneration of mechanical support is expected in the initial four months in order to provide sufficient mechanical support to the injured vessels. Although it is still arguable whether full mechanical support in stented lesions is mandatory during the first four months after implantation, it would certainly be a safety design parameter and a benchmark for regulatory evaluations based on the fact that there is insufficient human in vivo data available, especially the vessel wall mechanical properties during the healing/remodeling phase. Second, once the Mg alloy stent being degraded, the void space will be filled by the regenerated blood vessel tissues. The degradation of the Mg alloy stent should be 100% completed with no residues, and the degradation products (e.g., ions and hydrogen) will be helpful for the tissue reconstruction of the blood vessel. Toward this target, some future research perspectives are also discussed.

Bio-Adaption between Magnesium Alloy Stent and the Blood Vessel: A Review

PubMed Central

Ma, Jun; Zhao, Nan; Betts, Lexxus; Zhu, Donghui

2016-01-01

Biodegradable magnesium (Mg) alloy stents are the most promising next generation of bio-absorbable stents. In this article, we summarized the progresses on the in vitro studies, animal testing and clinical trials of biodegradable Mg alloy stents in the past decades. These exciting findings led us to propose the importance of the concept “bio-adaption” between the Mg alloy stent and the local tissue microenvironment after implantation. The healing responses of stented blood vessel can be generally described in three overlapping phases: inflammation, granulation and remodeling. The ideal bio-adaption of the Mg alloy stent, once implanted into the blood vessel, needs to be a reasonable function of the time and the space/dimension. First, a very slow degeneration of mechanical support is expected in the initial four months in order to provide sufficient mechanical support to the injured vessels. Although it is still arguable whether full mechanical support in stented lesions is mandatory during the first four months after implantation, it would certainly be a safety design parameter and a benchmark for regulatory evaluations based on the fact that there is insufficient human in vivo data available, especially the vessel wall mechanical properties during the healing/remodeling phase. Second, once the Mg alloy stent being degraded, the void space will be filled by the regenerated blood vessel tissues. The degradation of the Mg alloy stent should be 100% completed with no residues, and the degradation products (e.g., ions and hydrogen) will be helpful for the tissue reconstruction of the blood vessel. Toward this target, some future research perspectives are also discussed. PMID:27698548

Quantum phase space with a basis of Wannier functions

NASA Astrophysics Data System (ADS)

Fang, Yuan; Wu, Fan; Wu, Biao

2018-02-01

A quantum phase space with Wannier basis is constructed: (i) classical phase space is divided into Planck cells; (ii) a complete set of Wannier functions are constructed with the combination of Kohn’s method and Löwdin method such that each Wannier function is localized at a Planck cell. With these Wannier functions one can map a wave function unitarily onto phase space. Various examples are used to illustrate our method and compare it to Wigner function. The advantage of our method is that it can smooth out the oscillations in wave functions without losing any information and is potentially a better tool in studying quantum-classical correspondence. In addition, we point out that our method can be used for time-frequency analysis of signals.

Multivariable Hermite polynomials and phase-space dynamics

NASA Technical Reports Server (NTRS)

Dattoli, G.; Torre, Amalia; Lorenzutta, S.; Maino, G.; Chiccoli, C.

1994-01-01

The phase-space approach to classical and quantum systems demands for advanced analytical tools. Such an approach characterizes the evolution of a physical system through a set of variables, reducing to the canonically conjugate variables in the classical limit. It often happens that phase-space distributions can be written in terms of quadratic forms involving the above quoted variables. A significant analytical tool to treat these problems may come from the generalized many-variables Hermite polynomials, defined on quadratic forms in R(exp n). They form an orthonormal system in many dimensions and seem the natural tool to treat the harmonic oscillator dynamics in phase-space. In this contribution we discuss the properties of these polynomials and present some applications to physical problems.

Gauging Spatial Symmetries and the Classification of Topological Crystalline Phases

NASA Astrophysics Data System (ADS)

Thorngren, Ryan; Else, Dominic V.

2018-01-01

We put the theory of interacting topological crystalline phases on a systematic footing. These are topological phases protected by space-group symmetries. Our central tool is an elucidation of what it means to "gauge" such symmetries. We introduce the notion of a crystalline topological liquid and argue that most (and perhaps all) phases of interest are likely to satisfy this criterion. We prove a crystalline equivalence principle, which states that in Euclidean space, crystalline topological liquids with symmetry group G are in one-to-one correspondence with topological phases protected by the same symmetry G , but acting internally, where if an element of G is orientation reversing, it is realized as an antiunitary symmetry in the internal symmetry group. As an example, we explicitly compute, using group cohomology, a partial classification of bosonic symmetry-protected topological phases protected by crystalline symmetries in (3 +1 ) dimensions for 227 of the 230 space groups. For the 65 space groups not containing orientation-reversing elements (Sohncke groups), there are no cobordism invariants that may contribute phases beyond group cohomology, so we conjecture that our classification is complete.

Acquisition of Skill Proficiency Over Multiple Sessions of a Novel Rover Simulation

NASA Technical Reports Server (NTRS)

Dean, S. L.; DeDios,Y. E.; MacDougall, H. G.; Moore, S. T.; Wood, S. J.

2011-01-01

Following long-duration exploration transits, adaptive changes in sensorimotor function may impair the crew's ability to safely perform manual control tasks such as operating pressurized rovers. Postflight performance will also be influenced by the level of preflight skill proficiency they have attained. The purpose of this study was to characterize the acquisition of skills in a motion-based rover simulation over multiple sessions, and to investigate the effects of varying the simulation scenarios. METHODS: Twenty healthy subjects were tested in 5 sessions, with 1-3 days between sessions. Each session consisted of a serial presentation of 8 discrete tasks to be completed as quickly and accurately as possible. Each task consisted of 1) perspective-taking, using a map that defined a docking target, 2) navigation toward the target around a Martian outpost, and 3) docking a side hatch of the rover to a visually guided target. The simulator utilized a Stewart-type motion base (CKAS, Australia), single-seat cabin with triple scene projection covering 150 deg horizontal by 50 deg vertical, and joystick controller. Subjects were randomly assigned to a control group (tasks identical in the first 4 sessions) or a varied-practice group. The dependent variables for each task included accuracy toward the target and time to completion. RESULTS: The greatest improvements in time to completion occurred during the docking phase. The varied-practice group showed more improvement in perspective-taking accuracy. Perspective-taking accuracy was also affected by the relative orientation of the rover to the docking target. Skill acquisition was correlated with self-ratings of previous gaming experience. DISCUSSION: Varying task selection and difficulty will optimize the preflight acquisition of skills when performing novel operational tasks. Simulation of operational manual control will provide functionally relevant evidence regarding the impact of sensorimotor adaptation on early surface operations and what countermeasures are needed. Learning Objective: The use of a motion-based simulation to investigate decrements in the proficiency to operate pressurized rovers during early surface operations of space exploration missions, along with the acquisition of skill proficiency needed during the preflight phase of the mission.

Phase operator problem and macroscopic extension of quantum mechanics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ozawa, M.

1997-06-01

To find the Hermitian phase operator of a single-mode electromagnetic field in quantum mechanics, the Schr{umlt o}dinger representation is extended to a larger Hilbert space augmented by states with infinite excitation by nonstandard analysis. The Hermitian phase operator is shown to exist on the extended Hilbert space. This operator is naturally considered as the controversial limit of the approximate phase operators on finite dimensional spaces proposed by Pegg and Barnett. The spectral measure of this operator is a Naimark extension of the optimal probability operator-valued measure for the phase parameter found by Helstrom. Eventually, the two promising approaches to themore » statistics of the phase in quantum mechanics are synthesized by means of the Hermitian phase operator in the macroscopic extension of the Schr{umlt o}dinger representation. {copyright} 1997 Academic Press, Inc.« less

Early Program Development

NASA Image and Video Library

1969-01-01

This 1969 artist's concept illustrates the use of three major elements of NASA's Integrated program, as proposed by President Nixon's Space Task Group. In Phases I and II, a Space Tug with a manipulator-equipped crew module removes a cargo module from an early Space Shuttle Orbiter and docks with it. In Phases III and IV, the Space Tug with attached cargo module flys toward a Nuclear Shuttle. As a result of the Space Task Group's recommendations for more commonality and integration in the American space program, Marshall Space Flight Center engineers studied many of the spacecraft depicted here.

Space Launch System Update

NASA Technical Reports Server (NTRS)

Cobb, Sharon

2017-01-01

NASA has a phased approach to ensure our nation's leadership in space exploration, beginning in Earth orbit, developing our skills in lunar space, and extending those skills and technologies to a human mission to Mars. We're currently in Phase 0, using the ISS to better understand living and working in space. You may have heard about our "twin study" with astronauts Scott and Mike Kelly that's giving us valuable information on the effects of microgravity environments on the human body during long stays in LEO. During Phase 1 in the 2020s, SLS will be used to lift the pieces of a "deep space gateway" outpost to lunar orbit. Developing and operating the gateway will get us to Mars in a step-by-step fashion, with lessons learned in each phase of the process informing the next steps. First step of moving humans farther into the solar system is completing and flying SLS and Orion.

Microscopic Phase-Space Exploration Modeling of ^{258}Fm Spontaneous Fission.

PubMed

Tanimura, Yusuke; Lacroix, Denis; Ayik, Sakir

2017-04-14

We show that the total kinetic energy (TKE) of nuclei after the spontaneous fission of ^{258}Fm can be well reproduced using simple assumptions on the quantum collective phase space explored by the nucleus after passing the fission barrier. Assuming energy conservation and phase-space exploration according to the stochastic mean-field approach, a set of initial densities is generated. Each density is then evolved in time using the nuclear time-dependent density-functional theory with pairing. This approach goes beyond the mean-field theory by allowing spontaneous symmetry breaking as well as a wider dynamical phase-space exploration leading to larger fluctuations in collective space. The total kinetic energy and mass distributions are calculated. New information on the fission process: fluctuations in scission time, strong correlation between TKE and collective deformation, as well as prescission particle emission, are obtained. We conclude that fluctuations of the TKE and mass are triggered by quantum fluctuations.

Geometric phase of mixed states for three-level open systems

NASA Astrophysics Data System (ADS)

Jiang, Yanyan; Ji, Y. H.; Xu, Hualan; Hu, Li-Yun; Wang, Z. S.; Chen, Z. Q.; Guo, L. P.

2010-12-01

Geometric phase of mixed state for three-level open system is defined by establishing in connecting density matrix with nonunit vector ray in a three-dimensional complex Hilbert space. Because the geometric phase depends only on the smooth curve on this space, it is formulated entirely in terms of geometric structures. Under the limiting of pure state, our approach is in agreement with the Berry phase, Pantcharatnam phase, and Aharonov and Anandan phase. We find that, furthermore, the Berry phase of mixed state correlated to population inversions of three-level open system.

Qubits in phase space: Wigner-function approach to quantum-error correction and the mean-king problem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paz, Juan Pablo; Roncaglia, Augusto Jose; Theoretical Division, LANL, MSB213, Los Alamos, New Mexico 87545

2005-07-15

We analyze and further develop a method to represent the quantum state of a system of n qubits in a phase-space grid of NxN points (where N=2{sup n}). The method, which was recently proposed by Wootters and co-workers (Gibbons et al., Phys. Rev. A 70, 062101 (2004).), is based on the use of the elements of the finite field GF(2{sup n}) to label the phase-space axes. We present a self-contained overview of the method, we give insights into some of its features, and we apply it to investigate problems which are of interest for quantum-information theory: We analyze the phase-spacemore » representation of stabilizer states and quantum error-correction codes and present a phase-space solution to the so-called mean king problem.« less

Scientific management of Space Telescope

NASA Technical Reports Server (NTRS)

Odell, C. R.

1981-01-01

A historical summay is given on the science management of the Space Telescope, the inception of which began in 1962, when scientists and engineers first recommended the development of a nearly diffraction limited substantial-size optical telescope. Phase A, the feasibility requirements generation phase, began in 1971 and consisted largely of NASA scientists and a NASA design. Phase B, the preliminary design phase, established a tiered structure of scientists, led by the Large Space Telescope operations and Management Work Group. A Mission Operations Working Group headed six instrument definition teams to develop the essential instrument definitions. Many changes took place during Phase B, before design and development, which began in 1978 and still continues today.

Copernicus Space Component: Status and Evolution

NASA Astrophysics Data System (ADS)

Jutz, Simon; Milagro Perez, Maria Pilar

2017-04-01

The Copernicus environment-monitoring programme with its fleet of Sentinel satellites forming the heart of the programme's space component, entered its operational phase in 2014 with the launch of the first dedicated satellite, Sentinel-1 A. In the meantime three more spacecraft have been launched in 2015 and 2016 and other three will be launched this year. To complete the caravan of Sentinel satellites, eight more spacecraft and 5 additional Sentinel instruments, embarked on European meteorological satellites, will be put in orbit and will cover all environmental domains. The data are distributed free of charge as part of a European policy seeking to stimulate downstream value-added Earth observation-related business. With this space configuration, an uninterrupted data delivery to users is guaranteed until at least 2030. Over 54000 users world-wide are accessing Sentinel data from several data access hubs developed by ESA. Over 13 PB of data have been already downloaded with an average of several TB of data products downloaded every day, making Copernicus a Big Data challenge. These figures will grow as new satellites will be put in orbit. In the meantime, and thinking of a near term future, new priorities have been introduced in the EU policies and new societal needs and challenges have arisen requiring new observations. This will lead to what has been called the Sentinels' expansion. The expansion of the Sentinel family is a joint EU-ESA endeavour which just started concerning the investigation of new domains/techniques for future satellite missions like a greenhouse gases emissions mission, polar ice/ocean interferometric altimetry, thermal Infrared, soil moisture or hyper-spectral land imaging. This presentation will therefore give an overview of the current status of the space component and corresponding data access, and some hints on the future perspectives of the Copernicus space component.

Space station program phase B definition: Nuclear reactor-powered space station cost and schedules

NASA Technical Reports Server (NTRS)

1971-01-01

Tabulated data are presented on the costs, schedules, and technical characteristics for the space station phases C and D program. The work breakdown structure, schedule data, program ground rules, program costs, cost-estimating rationale, funding schedules, and supporting data are included.

Momentum space topology of QCD

NASA Astrophysics Data System (ADS)

Zubkov, M. A.

2018-06-01

We discuss the possibility to consider quark matter as the topological material. We consider hadronic phase (HP), the quark-gluon plasma phase (QGP), and the hypothetical color-flavor locking (CFL) phase. In those phases we identify the relevant topological invariants in momentum space. The formalism is developed, which relates those invariants and massless fermions that reside on vortices and at the interphases. This formalism is illustrated by the example of vortices in the CFL phase.

Controlling quantum interference in phase space with amplitude.

PubMed

Xue, Yinghong; Li, Tingyu; Kasai, Katsuyuki; Okada-Shudo, Yoshiko; Watanabe, Masayoshi; Zhang, Yun

2017-05-23

We experimentally show a quantum interference in phase space by interrogating photon number probabilities (n = 2, 3, and 4) of a displaced squeezed state, which is generated by an optical parametric amplifier and whose displacement is controlled by amplitude of injected coherent light. It is found that the probabilities exhibit oscillations of interference effect depending upon the amplitude of the controlling light field. This phenomenon is attributed to quantum interference in phase space and indicates the capability of controlling quantum interference using amplitude. This remarkably contrasts with the oscillations of interference effects being usually controlled by relative phase in classical optics.

A phase space approach to imaging from limited data

NASA Astrophysics Data System (ADS)

Testorf, Markus E.

2015-09-01

The optical instrument function is used as the basis to develop optical system theory for imaging applications. The detection of optical signals is conveniently described as the overlap integral of the Wigner distribution functions of instrument and optical signal. Based on this framework various optical imaging systems, including plenoptic cameras, phase-retrieval algorithms, and Shack-Hartman sensors are shown to acquire information about a domain in phase-space, with finite extension and finite resolution. It is demonstrated how phase space optics can be used both to analyze imaging systems, as well as for designing methods for image reconstruction.

Optical cryptography topology based on a three-dimensional particle-like distribution and diffractive imaging.

PubMed

Chen, Wen; Chen, Xudong

2011-05-09

In recent years, coherent diffractive imaging has been considered as a promising alternative for information retrieval instead of conventional interference methods. Coherent diffractive imaging using the X-ray light source has opened up a new research perspective for the measurement of non-crystalline and biological specimens, and can achieve unprecedentedly high resolutions. In this paper, we show how a three-dimensional (3D) particle-like distribution and coherent diffractive imaging can be applied for a study of optical cryptography. An optical multiple-random-phase-mask encoding approach is used, and the plaintext is considered as a series of particles distributed in a 3D space. A topology concept is also introduced into the proposed optical cryptosystem. During image decryption, a retrieval algorithm is developed to extract the plaintext from the ciphertexts. In addition, security and advantages of the proposed optical cryptography topology are also analyzed. © 2011 Optical Society of America

An optimal general type-2 fuzzy controller for Urban Traffic Network.

PubMed

Khooban, Mohammad Hassan; Vafamand, Navid; Liaghat, Alireza; Dragicevic, Tomislav

2017-01-01

Urban traffic network model is illustrated by state-charts and object-diagram. However, they have limitations to show the behavioral perspective of the Traffic Information flow. Consequently, a state space model is used to calculate the half-value waiting time of vehicles. In this study, a combination of the general type-2 fuzzy logic sets and the Modified Backtracking Search Algorithm (MBSA) techniques are used in order to control the traffic signal scheduling and phase succession so as to guarantee a smooth flow of traffic with the least wait times and average queue length. The parameters of input and output membership functions are optimized simultaneously by the novel heuristic algorithm MBSA. A comparison is made between the achieved results with those of optimal and conventional type-1 fuzzy logic controllers. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Lorenz curve of a light beam: evaluating beam quality from a majorization perspective.

PubMed

Porras, Miguel A; Gonzalo, Isabel; Ahmir Malik, M

2017-08-01

We introduce a novel approach for the characterization of the quality of a laser beam that is not based on particular criteria for beam width definition. The Lorenz curve of a light beam is a sophisticated version of the so-called power-in-the-bucket curve, formed by the partial sums of discretized joint intensity distribution in the near and far fields, sorted in decreasing order. According to majorization theory, a higher Lorenz curve implies that all measures of spreading in phase space, and, in particular, all Rényi (and Shannon) entropy-based measures of the beam width products in near and far fields, are unanimously smaller, providing a strong assessment of a better beam quality. Two beams whose Lorenz curves intersect can be considered of relatively better or lower quality only according to specific criteria, which can be inferred from the plot of the respective Lorenz curves.

Direct weak localization signature with ultracold atoms: the CBS revival

NASA Astrophysics Data System (ADS)

Josse, Vincent

2016-05-01

Ultracold atomic systems in presence of disorder have attracted a lot of interest over the past decade, in particular to study the physics of Anderson localization (AL) in a renewed perspective. Landmark experiments have been demonstrated, in 1D and 3D geometries. However many challenges remain and new ideas have emerged, as for instance the search for original signatures of Anderson localization in momentum space. Here I will describe our progresses along that line where a weak localization effect has been directly observed, i.e. the Coherent Backscattering (CBS) phenomenon. In particular I will report on the recent observation of suppression and revival of CBS when a controlled dephasing kick is applied to the system. This observation demonstrates a novel and general method, introduced by T. Micklitz and coworkers, to study probe phase coherence in disordered systems by manipulating time reversal symmetry.

Hamiltonian analysis of higher derivative scalar-tensor theories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langlois, David; Noui, Karim, E-mail: langlois@apc.univ-paris7.fr, E-mail: karim.noui@lmpt.univ-tours.fr

2016-07-01

We perform a Hamiltonian analysis of a large class of scalar-tensor Lagrangians which depend quadratically on the second derivatives of a scalar field. By resorting to a convenient choice of dynamical variables, we show that the Hamiltonian can be written in a very simple form, where the Hamiltonian and the momentum constraints are easily identified. In the case of degenerate Lagrangians, which include the Horndeski and beyond Horndeski quartic Lagrangians, our analysis confirms that the dimension of the physical phase space is reduced by the primary and secondary constraints due to the degeneracy, thus leading to the elimination of themore » dangerous Ostrogradsky ghost. We also present the Hamiltonian formulation for nondegenerate theories and find that they contain four degrees of freedom, including a ghost, as expected. We finally discuss the status of the unitary gauge from the Hamiltonian perspective.« less

How Supervisor Experience Influences Trust, Supervision, and Trainee Learning: A Qualitative Study.

PubMed

Sheu, Leslie; Kogan, Jennifer R; Hauer, Karen E

2017-09-01

Appropriate trust and supervision facilitate trainees' growth toward unsupervised practice. The authors investigated how supervisor experience influences trust, supervision, and subsequently trainee learning. In a two-phase qualitative inductive content analysis, phase one entailed reviewing 44 internal medicine resident and attending supervisor interviews from two institutions (July 2013 to September 2014) for themes on how supervisor experience influences trust and supervision. Three supervisor exemplars (early, developing, experienced) were developed and shared in phase two focus groups at a single institution, wherein 23 trainees validated the exemplars and discussed how each impacted learning (November 2015). Phase one: Four domains of trust and supervision varying with experience emerged: data, approach, perspective, clinical. Early supervisors were detail oriented and determined trust depending on task completion (data), were rule based (approach), drew on their experiences as trainees to guide supervision (perspective), and felt less confident clinically compared with more experienced supervisors (clinical). Experienced supervisors determined trust holistically (data), checked key aspects of patient care selectively and covertly (approach), reflected on individual experiences supervising (perspective), and felt comfortable managing clinical problems and gauging trainee abilities (clinical). Phase two: Trainees felt the exemplars reflected their experiences, described their preferences and learning needs shifting over time, and emphasized the importance of supervisor flexibility to match their learning needs. With experience, supervisors differ in their approach to trust and supervision. Supervisors need to trust themselves before being able to trust others. Trainees perceive these differences and seek supervision approaches that align with their learning needs.

Lorenz, Gödel and Penrose: new perspectives on determinism and causality in fundamental physics

NASA Astrophysics Data System (ADS)

Palmer, T. N.

2014-07-01

Despite being known for his pioneering work on chaotic unpredictability, the key discovery at the core of meteorologist Ed Lorenz's work is the link between space-time calculus and state-space fractal geometry. Indeed, properties of Lorenz's fractal invariant set relate space-time calculus to deep areas of mathematics such as Gödel's Incompleteness Theorem. Could such properties also provide new perspectives on deep unsolved issues in fundamental physics? Recent developments in cosmology motivate what is referred to as the 'cosmological invariant set postulate': that the universe ? can be considered a deterministic dynamical system evolving on a causal measure-zero fractal invariant set ? in its state space. Symbolic representations of ? are constructed explicitly based on permutation representations of quaternions. The resulting 'invariant set theory' provides some new perspectives on determinism and causality in fundamental physics. For example, while the cosmological invariant set appears to have a rich enough structure to allow a description of (quantum) probability, its measure-zero character ensures it is sparse enough to prevent invariant set theory being constrained by the Bell inequality (consistent with a partial violation of the so-called measurement independence postulate). The primacy of geometry as embodied in the proposed theory extends the principles underpinning general relativity. As a result, the physical basis for contemporary programmes which apply standard field quantisation to some putative gravitational lagrangian is questioned. Consistent with Penrose's suggestion of a deterministic but non-computable theory of fundamental physics, an alternative 'gravitational theory of the quantum' is proposed based on the geometry of ?, with new perspectives on the problem of black-hole information loss and potential observational consequences for the dark universe.

The Space Shuttle in perspective

NASA Technical Reports Server (NTRS)

Hosenball, S. N.

1981-01-01

Commercial aspects of the Space Shuttle are examined, with attention given to charges to users, schedule of launches and reimbursement, kinds of payload and their selection, NASA authority, space allocation, and risk, liability, and insurance. It is concluded that insurance to reduce the risk, incentives that NASA is willing to make available to U.S. industry, and the demonstrated willingness of industry and the financial community to invest their funds in space ventures indicate that the new Shuttle capabilities will exponentially increase commercial activities in space during the 1980s.

Gradient Space under Orthography and Perspective

DTIC Science & Technology

1982-05-24

surfaceorientation to image geometry [8, 9, 10, 13, 15]. The descriptions of important gradient space properties, however, have been scattered throughout...Kanade, T. A Theory of Origami World. Artificial Intelligence 13:279-311, 1980. *[8] Kanade, T. and Kender, J. Mapping Image Properies into Shape

DSCOVR Featured Articles

Atmospheric Science Data Center

2017-01-11

...   An EPIC Eclipse: Natural Hazards  - The Deep Space Climate Observatory (DSCOVR) was built to provide a distinct perspective ... DSCOVR  - The journey has been a long one for the Deep Space Climate Observatory (DSCOVR).  An EPIC New View of Earth: Image of ...

Hearing on Space Situational Awareness:

NASA Image and Video Library

2018-06-22

Secretary of Commerce Wilbur Ross testifies before the House Subcommittee on Strategic Forces during a hearing on Space Situational Awareness: Whole of Government Perspectives on Roles and Responsibilities, Friday, June 22, 2018 at the Rayburn House Office Building in Washington. Photo Credit: (NASA/Bill Ingalls)

Dynamics of spacing adjustment and recovery mechanisms of ABAC-type growth pattern in ternary eutectic systems

NASA Astrophysics Data System (ADS)

Mohagheghi, Samira; Şerefoğlu, Melis

2017-07-01

In directionally solidified 2D samples at ternary eutectic compositions, the stable three-phase pattern is established to be lamellar structure with ABAC stacking, where A, B, and C are crystalline phases. Beyond the stability limits of the ABAC pattern, the system uses various spacing adjustment mechanisms to revert to the stable regime. In this study, the dynamics of spacing adjustment and recovery mechanisms of isotropic ABAC patterns were investigated using three-phase In-Bi-Sn alloy. Unidirectional solidification experiments were performed on 23.0 and 62.7 μm-thick samples, where solidification front was monitored in real-time from both sides of the sample using a particular microscopy system. At these thicknesses, the pattern was found to be 2D during steady-state growth, i.e. both top and bottom microstructures were the same. However, during spacing adjustment and recovery mechanisms, 3D features were observed. Dynamics of two major instabilities, lamellae branching and elimination, were quantified. After these instabilities, two key ABAC pattern recovery mechanisms, namely, phase invasion and phase exchange processes, were identified and analyzed. After elimination, ABAC pattern is recovered by either continuous eliminations of all phases or by phase exchange. After branching, the recovery mechanisms are established to be phase invasion and phase exchange.

Performance evaluation of digital phase-locked loops for advanced deep space transponders

NASA Technical Reports Server (NTRS)

Nguyen, T. M.; Hinedi, S. M.; Yeh, H.-G.; Kyriacou, C.

1994-01-01

The performances of the digital phase-locked loops (DPLL's) for the advanced deep-space transponders (ADT's) are investigated. DPLL's considered in this article are derived from the analog phase-locked loop, which is currently employed by the NASA standard deep space transponder, using S-domain to Z-domain mapping techniques. Three mappings are used to develop digital approximations of the standard deep space analog phase-locked loop, namely the bilinear transformation (BT), impulse invariant transformation (IIT), and step invariant transformation (SIT) techniques. The performance in terms of the closed loop phase and magnitude responses, carrier tracking jitter, and response of the loop to the phase offset (the difference between in incoming phase and reference phase) is evaluated for each digital approximation. Theoretical results of the carrier tracking jitter for command-on and command-off cases are then validated by computer simulation. Both theoretical and computer simulation results show that at high sampling frequency, the DPLL's approximated by all three transformations have the same tracking jitter. However, at low sampling frequency, the digital approximation using BT outperforms the others. The minimum sampling frequency for adequate tracking performance is determined for each digital approximation of the analog loop. In addition, computer simulation shows that the DPLL developed by BT provides faster response to the phase offset than IIT and SIT.

Being White in Black Spaces: Teaching and Learning at a Predominately Black Institution

ERIC Educational Resources Information Center

Harrington, Timothy E.; Thomas, Michael

2018-01-01

This paper serves as a beginning conversation of how two White males perspectives' were shaped and how those perspectives evolved while attending and teaching at a Predominately Black Institution (PBI). Their initial understandings of Whiteness are introduced. This is an ethnographic study that utilized personal narratives from a college professor…

State College Scavenger: Evaluating the Perspectives of Mobile Computing Interactions within Community Spaces

ERIC Educational Resources Information Center

Hoffman, Blaine

2013-01-01

This work focuses on the impact of mobile computing on individuals' perspectives of places within their community. A technological intervention is designed and deployed to augment the user experience of visiting different locations around town, physically exploring them while also interacting with an online tool. The tool-supported activity serves…

Views from inside the Shed: Young Children's Perspectives of the Outdoor Environment

ERIC Educational Resources Information Center

Clark, Alison

2007-01-01

This article examines messages from participatory research about young children's perspectives of early childhood environments and outdoor spaces in particular. The studies chosen have been carried out in England with children under six years old using the Mosaic approach and are compared with findings from an Icelandic study using the same…

Opening up "Spaces for Manoeuvre": English Teacher Perspectives on Learner Motivation

ERIC Educational Resources Information Center

Glas, Katharina

2016-01-01

This qualitative study explores teachers' perspectives on learner motivation for English in Chilean secondary schools. Drawing both on motivation theories and on concepts related to teacher cognition, autonomy and agency, the analysis of 19 semi-structured interviews with Chilean English teachers sheds light on the difficulties that many teachers…

A Spacefaring People: Perspectives on Early Spaceflight.

ERIC Educational Resources Information Center

Roland, Alex

A conference on the history of space activity was convened at Yale University in 1981 and perspectives from history, political science, journalism, politics, science, and literature were exchanged. The essays in this publication serve as the proceedings for that conference. The papers are presented in four major theme areas. These include: (1)…

PUS Services Software Building Block Automatic Generation for Space Missions

NASA Astrophysics Data System (ADS)

Candia, S.; Sgaramella, F.; Mele, G.

2008-08-01

The Packet Utilization Standard (PUS) has been specified by the European Committee for Space Standardization (ECSS) and issued as ECSS-E-70-41A to define the application-level interface between Ground Segments and Space Segments. The ECSS-E- 70-41A complements the ECSS-E-50 and the Consultative Committee for Space Data Systems (CCSDS) recommendations for packet telemetry and telecommand. The ECSS-E-70-41A characterizes the identified PUS Services from a functional point of view and the ECSS-E-70-31 standard specifies the rules for their mission-specific tailoring. The current on-board software design for a space mission implies the production of several PUS terminals, each providing a specific tailoring of the PUS services. The associated on-board software building blocks are developed independently, leading to very different design choices and implementations even when the mission tailoring requires very similar services (from the Ground operative perspective). In this scenario, the automatic production of the PUS services building blocks for a mission would be a way to optimize the overall mission economy and improve the robusteness and reliability of the on-board software and of the Ground-Space interactions. This paper presents the Space Software Italia (SSI) activities for the development of an integrated environment to support: the PUS services tailoring activity for a specific mission. the mission-specific PUS services configuration. the generation the UML model of the software building block implementing the mission-specific PUS services and the related source code, support documentation (software requirements, software architecture, test plans/procedures, operational manuals), and the TM/TC database. The paper deals with: (a) the project objectives, (b) the tailoring, configuration, and generation process, (c) the description of the environments supporting the process phases, (d) the characterization of the meta-model used for the generation, (e) the characterization of the reference avionics architecture and of the reference on- board software high-level architecture.

Time-dependent radiation dose estimations during interplanetary space flights

NASA Astrophysics Data System (ADS)

Dobynde, M. I.; Shprits, Y.; Drozdov, A.

2015-12-01

Time-dependent radiation dose estimations during interplanetary space flights 1,2Dobynde M.I., 2,3Drozdov A.Y., 2,4Shprits Y.Y.1Skolkovo institute of science and technology, Moscow, Russia 2University of California Los Angeles, Los Angeles, USA 3Lomonosov Moscow State University Skobeltsyn Institute of Nuclear Physics, Moscow, Russia4Massachusetts Institute of Technology, Cambridge, USASpace radiation is the main restriction for long-term interplanetary space missions. It induces degradation of external components and propagates inside providing damage to internal environment. Space radiation particles and induced secondary particle showers can lead to variety of damage to astronauts in short- and long- term perspective. Contribution of two main sources of space radiation- Sun and out-of-heliosphere space varies in time in opposite phase due to the solar activity state. Currently the only habituated mission is the international interplanetary station that flights on the low Earth orbit. Besides station shell astronauts are protected with the Earth magnetosphere- a natural shield that prevents significant damage for all humanity. Current progress in space exploration tends to lead humanity out of magnetosphere bounds. With the current study we make estimations of spacecraft parameters and astronauts damage for long-term interplanetary flights. Applying time dependent model of GCR spectra and data on SEP spectra we show the time dependence of the radiation in a human phantom inside the shielding capsule. We pay attention to the shielding capsule design, looking for an optimal geometry parameters and materials. Different types of particles affect differently on the human providing more or less harm to the tissues. Incident particles provide a large amount of secondary particles while propagating through the shielding capsule. We make an attempt to find an optimal combination of shielding capsule parameters, namely material and thickness, that will effectively decrease the incident particle energy, at the same time minimizing flow of secondary induced particles and minimizing most harmful particle types flows.

Psychophysiological aspects of increasing resistance to space motion sickness.

PubMed

Berezhnov, E S; Vorobjev, O A; Lapaev, E V

1993-02-01

One of the actual and difficulty solved problems of the adaptation period to microgravitation is space motion sickness (MS) that has the negative influence on well-being and performance of crewmembers in the initial and highly crucial phase of the orbital flight. Among the prophylactic measures for decrease of the unfavourable influence of space MS the preflight training is of great importance, and its role in perspective undoubtedly will grow in connection with increase of the number of crewmembers. During the last years several authors received experimental materials evidenced that as a base of more effective increase of resistance to space MS there may be used adequate modelling of the main physiological effects of the adaptation period to microgravitation. In the most investigations the main attention is paid to modelling of "conflicting" vestibular-visual (VV) impacts. In other hand, in connection with the contradictory materials about the role of hemodynamic component in the development of space MS this effect of microgravitation conditions, as a rule, is not modelled in the methods of resistance enhancement to space MS. Hence in this work there was put a task to investigate the efficiency of application of different combination of VV-impacts and creation of redistribution of liquid medium of an organism in the cranial direction for increase of man resistance to space MS. For resolving this task there was used the specially developed stand, made in two modifications. This stand provided redistribution of liquid medium of an organism in the cranial direction by putting the investigated individual into the antiorthostatic position (AOP). During the rotation around the vertical axis individual was placed in such supine position on the turn table that labyrinth of the inner ear should be displaced by 8-10 centimeters from the axis of rotation to the head edge of the turn table. This increased the adequacy of vestibular apparatus irritation by gravitation and inertia forces with regard to microgravitation conditions.

Simulations of phase space distributions of storm time proton ring current

NASA Technical Reports Server (NTRS)

Chen, Margaret W.; Lyons, Larry R.; Schulz, Michael

1994-01-01

We use results of guiding-center simulations of ion transport to map phase space densities of the stormtime proton ring current. We model a storm as a sequence of substorm-associated enhancements in the convection electric field. Our pre-storm phase space distribution is an analytical solution to a steady-state transport model in which quiet-time radial diffusion balances charge exchange. This pre-storm phase space spectra at L approximately 2 to 4 reproduce many of the features found in observed quiet-time spectra. Using results from simulations of ion transport during model storms having main phases of 3, 6, and 12 hr, we map phase space distributions from the pre-storm distribution in accordance with Liouville's theorem. We find stormtime enhancements in the phase space densities at energies E approximately 30-160 keV for L approximately 2.5 to 4. These enhancements agree well with the observed stormtime ring current. For storms with shorter main phases (approximately 3 hr), the enhancements are caused mainly by the trapping of ions injected from open night side trajectories, and diffusive transport of higher-energy (greater than or approximately 160 keV) ions contributes little to the stormtime ring current. However, the stormtime ring current is augmented also by the diffusive transport of higher-energy ions (E greater than or approximately 160 keV) durinng stroms having longer main phases (greater than or approximately 6 hr). In order to account for the increase in Dst associated with the formation of the stormtime ring current, we estimate the enhancement in particle-energy content that results from stormtime ion transport in the equatorial magnetosphere. We find that transport alone cannot account for the entire increase in absolute value of Dst typical of a major storm. However, we can account for the entire increase in absolute value of Dst by realistically increasing the stormtime outer boundary value of the phase space density relative to the quiet-time value. We compute the magnetic field produced by the ring current itself and find that radial profiles of the magnetic field depression resemble those obtained from observational data.

Phase III Simplified Integrated Test (SIT) results - Space Station ECLSS testing

NASA Technical Reports Server (NTRS)

Roberts, Barry C.; Carrasquillo, Robyn L.; Dubiel, Melissa Y.; Ogle, Kathryn Y.; Perry, Jay L.; Whitley, Ken M.

1990-01-01

During 1989, phase III testing of Space Station Freedom Environmental Control and Life Support Systems (ECLSS) began at Marshall Space Flight Center (MSFC) with the Simplified Integrated Test. This test, conducted at the MSFC Core Module Integration Facility (CMIF), was the first time the four baseline air revitalization subsystems were integrated together. This paper details the results and lessons learned from the phase III SIT. Future plans for testing at the MSFC CMIF are also discussed.

Peaks in Phase Space Density: A Survey of the Van Allen Probes Era

NASA Astrophysics Data System (ADS)

Boyd, A. J.; Turner, D. L.; Reeves, G. D.; Spence, H. E.

2017-12-01

One of the challenges of radiation belt studies is the differentiation between acceleration mechanisms, particularly local acceleration and radial diffusion. This is often done through careful examination of phase space density profiles in terms of adiabatic coordinates. In particular, local acceleration processes produce growing peaks in phase space density. Many previous studies have shown clear observations of these features for individual events. However, it remains unclear how often and where these growing peaks are observed over a long time period. With the availability of several years of high quality observations from multiple spacecraft, we now have an opportunity to quantify phase space density profiles not only for multiple events, but also across a wide range of energies. In this study, we examine phase space density from more than four years of data from the Van Allen Probes and THEMIS to determine the statistical properties of the observed peaks in phase space density. First, we determine how often growing peaks are observed. Second, we examine where the peaks are located in terms of the adiabatic invariants mu, K and L* and how these locations relate to geomagnetic indices, solar wind conditions and the plasmapause location. Third, we explore how these peaks evolve in time. Together, these results will reveal the relative importance of different acceleration processes and how these affect the various electron populations within the radiation belt.

Evaluating Trauma Sonography for Operational Use in the Microgravity Environment

NASA Technical Reports Server (NTRS)

Kirkpatrick, Andrew W.; Jones, Jeffrey A.; Sargsyan, Ashot; Hamilton, Douglas; Melton, Shannon; Beck, George; Nicolaou, Savvas; Campbell, Mark; Dulchavsky, Scott

2007-01-01

Sonography is the only medical imaging modality aboard the ISS, and is likely to remain the leading imaging modality in future human space flight programs. While trauma sonography (TS) has been well recognized for terrestrial trauma settings, the technique had to be evaluated for suitability in space flight prior to adopting it as an operational capability. The authors found the following four-phased evaluative approach applicable to this task: 1) identifying standard or novel terrestrial techniques for potential use in space medicine; 2) developing and testing these techniques with suggested modifications on the ground (1g) either in clinical settings or in animal models, as appropriate; 3) evaluating and refining the techniques in parabolic flight (0g); and 4) validating and implementing for clinical use in space. In Phase I of the TS project, expert opinion and literature review suggested TS to be a potential screening tool for trauma in space. In Phase II, animal models were developed and tested in ground studies, and clinical studies were carried out in collaborating trauma centers. In Phase III, animal models were flight-tested in the NASA KC-135 Reduced Gravity Laboratory. Preliminary results of the first three phases demonstrated potential clinical utility of TS in microgravity. Phase IV studies have begun to address crew training issues, on-board imaging protocols, and data transfer procedures necessary to offer the modified TS technique for space use.

White-light diffraction phase microscopy at doubled space-bandwidth product.

PubMed

Shan, Mingguang; Kandel, Mikhail E; Majeed, Hassaan; Nastasa, Viorel; Popescu, Gabriel

2016-12-12

White light diffraction microscopy (wDPM) is a quantitative phase imaging method that benefits from both temporal and spatial phase sensitivity, granted, respectively, by the common-path geometry and white light illumination. However, like all off-axis quantitative phase imaging methods, wDPM is characterized by a reduced space-bandwidth product compared to phase shifting approaches. This happens essentially because the ultimate resolution of the image is governed by the period of the interferogram and not just the diffraction limit. As a result, off-axis techniques generates single-shot, i.e., high time-bandwidth, phase measurements, at the expense of either spatial resolution or field of view. Here, we show that combining phase-shifting and off-axis, the original space-bandwidth is preserved. Specifically, we developed phase-shifting diffraction phase microscopy with white light, in which we measure and combine two phase shifted interferograms. Due to the white light illumination, the phase images are characterized by low spatial noise, i.e., <1nm pathlength. We illustrate the operation of the instrument with test samples, blood cells, and unlabeled prostate tissue biopsy.

Grassmann phase space theory and the Jaynes-Cummings model

NASA Astrophysics Data System (ADS)

Dalton, B. J.; Garraway, B. M.; Jeffers, J.; Barnett, S. M.

2013-07-01

The Jaynes-Cummings model of a two-level atom in a single mode cavity is of fundamental importance both in quantum optics and in quantum physics generally, involving the interaction of two simple quantum systems—one fermionic system (the TLA), the other bosonic (the cavity mode). Depending on the initial conditions a variety of interesting effects occur, ranging from ongoing oscillations of the atomic population difference at the Rabi frequency when the atom is excited and the cavity is in an n-photon Fock state, to collapses and revivals of these oscillations starting with the atom unexcited and the cavity mode in a coherent state. The observation of revivals for Rydberg atoms in a high-Q microwave cavity is key experimental evidence for quantisation of the EM field. Theoretical treatments of the Jaynes-Cummings model based on expanding the state vector in terms of products of atomic and n-photon states and deriving coupled equations for the amplitudes are a well-known and simple method for determining the effects. In quantum optics however, the behaviour of the bosonic quantum EM field is often treated using phase space methods, where the bosonic mode annihilation and creation operators are represented by c-number phase space variables, with the density operator represented by a distribution function of these variables. Fokker-Planck equations for the distribution function are obtained, and either used directly to determine quantities of experimental interest or used to develop c-number Langevin equations for stochastic versions of the phase space variables from which experimental quantities are obtained as stochastic averages. Phase space methods have also been developed to include atomic systems, with the atomic spin operators being represented by c-number phase space variables, and distribution functions involving these variables and those for any bosonic modes being shown to satisfy Fokker-Planck equations from which c-number Langevin equations are often developed. However, atomic spin operators satisfy the standard angular momentum commutation rules rather than the commutation rules for bosonic annihilation and creation operators, and are in fact second order combinations of fermionic annihilation and creation operators. Though phase space methods in which the fermionic operators are represented directly by c-number phase space variables have not been successful, the anti-commutation rules for these operators suggest the possibility of using Grassmann variables—which have similar anti-commutation properties. However, in spite of the seminal work by Cahill and Glauber and a few applications, the use of phase space methods in quantum optics to treat fermionic systems by representing fermionic annihilation and creation operators directly by Grassmann phase space variables is rather rare. This paper shows that phase space methods using a positive P type distribution function involving both c-number variables (for the cavity mode) and Grassmann variables (for the TLA) can be used to treat the Jaynes-Cummings model. Although it is a Grassmann function, the distribution function is equivalent to six c-number functions of the two bosonic variables. Experimental quantities are given as bosonic phase space integrals involving the six functions. A Fokker-Planck equation involving both left and right Grassmann differentiations can be obtained for the distribution function, and is equivalent to six coupled equations for the six c-number functions. The approach used involves choosing the canonical form of the (non-unique) positive P distribution function, in which the correspondence rules for the bosonic operators are non-standard and hence the Fokker-Planck equation is also unusual. Initial conditions, such as those above for initially uncorrelated states, are discussed and used to determine the initial distribution function. Transformations to new bosonic variables rotating at the cavity frequency enable the six coupled equations for the new c-number functions-that are also equivalent to the canonical Grassmann distribution function-to be solved analytically, based on an ansatz from an earlier paper by Stenholm. It is then shown that the distribution function is exactly the same as that determined from the well-known solution based on coupled amplitude equations. In quantum-atom optics theories for many atom bosonic and fermionic systems are needed. With large atom numbers, treatments must often take into account many quantum modes—especially for fermions. Generalisations of phase space distribution functions of phase space variables for a few modes to phase space distribution functionals of field functions (which represent the field operators, c-number fields for bosons, Grassmann fields for fermions) are now being developed for large systems. For the fermionic case, the treatment of the simple two mode problem represented by the Jaynes-Cummings model is a useful test case for the future development of phase space Grassmann distribution functional methods for fermionic applications in quantum-atom optics.

Introduction to Group Relations and Organizational Diagnosis.

DTIC Science & Technology

The perspective of Group Relations and Organizational Diagnosis did not emerge from a vacuum. It is rooted in a clinical perspective on the study of... diagnosis became a specialty in its own right. Earlier treatments of organizational diagnosis , like the initial studies of organizational behavior...to the potential advances suggested by an intergroup perspective. The earlier works also varied in the degree to which they contributed to the entry, data collection, or feedback phases of organizational diagnosis .

Oscillatory networks of high-level mental alignment: A perspective-taking MEG study.

PubMed

Seymour, R A; Wang, H; Rippon, G; Kessler, K

2018-08-15

Mentally imagining another's perspective is a high-level social process, reliant on manipulating internal representations of the self in an embodied manner. Recently Wang et al. (2016) showed that theta-band (3-7 Hz) brain oscillations within the right temporo-parietal junction (rTPJ) and brain regions coding for motor/body schema contribute to the process of perspective-taking. Using a similar paradigm, we set out to unravel the extended functional brain network in detail. Increasing the angle between self and other perspective was accompanied by longer reaction times and increases in theta power within rTPJ, right lateral prefrontal cortex (PFC) and right anterior cingulate cortex (ACC). Using Granger-causality, we showed that lateral PFC and ACC exert top-down influence over rTPJ, indicative of executive control processes required for managing conflicts between self and other perspectives. Finally, we quantified patterns of whole-brain phase coupling in relation to the rTPJ. Results suggest that rTPJ increases its theta-band phase synchrony with brain regions involved in mentalizing and regions coding for motor/body schema; whilst decreasing synchrony to visual regions. Implications for neurocognitive models are discussed, and it is proposed that rTPJ acts as a 'hub' to route bottom-up visual information to internal representations of the self during perspective-taking, co-ordinated by theta-band oscillations. Copyright © 2018 Elsevier Inc. All rights reserved.

A pilot study of river flow prediction in urban area based on phase space reconstruction

NASA Astrophysics Data System (ADS)

Adenan, Nur Hamiza; Hamid, Nor Zila Abd; Mohamed, Zulkifley; Noorani, Mohd Salmi Md

2017-08-01

River flow prediction is significantly related to urban hydrology impact which can provide information to solve any problems such as flood in urban area. The daily river flow of Klang River, Malaysia was chosen to be forecasted in this pilot study which based on phase space reconstruction. The reconstruction of phase space involves a single variable of river flow data to m-dimensional phase space in which the dimension (m) is based on the optimal values of Cao method. The results from the reconstruction of phase space have been used in the forecasting process using local linear approximation method. From our investigation, river flow at Klang River is chaotic based on the analysis from Cao method. The overall results provide good value of correlation coefficient. The value of correlation coefficient is acceptable since the area of the case study is influence by a lot of factors. Therefore, this pilot study may be proposed to forecast daily river flow data with the purpose of providing information about the flow of the river system in urban area.

Grain size dependent phase stabilities and presence of a monoclinic (Pm) phase in the morphotropic phase boundary region of (1−x)Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} piezoceramics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Upadhyay, Ashutosh; Singh, Akhilesh Kumar, E-mail: akhilesh-bhu@yahoo.com, E-mail: aksingh.mst@itbhu.ac.in

2015-04-14

Results of the room temperature structural studies on (1−x)Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} ceramics using Rietveld analysis of the powder x-ray diffraction data in the composition range 0.28 ≤ x ≤ 0.45 are presented. The morphotropic phase boundary region exhibits coexistence of monoclinic (space group Pm) and tetragonal (space group P4 mm) phases in the composition range 0.33 ≤ x ≤ 0.40. The structure is nearly single phase monoclinic (space group Pm) in the composition range 0.28 ≤ x ≤ 0.32. The structure for the compositions with x ≥ 0.45 is found to be predominantly tetragonal with space group P4 mm. Rietveld refinement of the structure rules out the coexistence of rhombohedral and tetragonal phases inmore » the morphotropic phase boundary region reported by earlier authors. The Rietveld structure analysis for the sample x = .35 calcined at various temperatures reveals that phase fraction of the coexisting phases in the morphotropic phase boundary region varies with grain size. The structural parameters of the two coexisting phases also change slightly with changing grain size.« less

Using the phase-space imager to analyze partially coherent imaging systems: bright-field, phase contrast, differential interference contrast, differential phase contrast, and spiral phase contrast

NASA Astrophysics Data System (ADS)

Mehta, Shalin B.; Sheppard, Colin J. R.

2010-05-01

Various methods that use large illumination aperture (i.e. partially coherent illumination) have been developed for making transparent (i.e. phase) specimens visible. These methods were developed to provide qualitative contrast rather than quantitative measurement-coherent illumination has been relied upon for quantitative phase analysis. Partially coherent illumination has some important advantages over coherent illumination and can be used for measurement of the specimen's phase distribution. However, quantitative analysis and image computation in partially coherent systems have not been explored fully due to the lack of a general, physically insightful and computationally efficient model of image formation. We have developed a phase-space model that satisfies these requirements. In this paper, we employ this model (called the phase-space imager) to elucidate five different partially coherent systems mentioned in the title. We compute images of an optical fiber under these systems and verify some of them with experimental images. These results and simulated images of a general phase profile are used to compare the contrast and the resolution of the imaging systems. We show that, for quantitative phase imaging of a thin specimen with matched illumination, differential phase contrast offers linear transfer of specimen information to the image. We also show that the edge enhancement properties of spiral phase contrast are compromised significantly as the coherence of illumination is reduced. The results demonstrate that the phase-space imager model provides a useful framework for analysis, calibration, and design of partially coherent imaging methods.

A social science perspective on the forest preserves: Seven virtues for connecting people and nature

Treesearch

Paul H. Gobster

2015-01-01

How do people perceive and value urban green space? In what ways do people's perceptions and values of urban nature affect their use and experience of parks, forest preserves, and other green space types? Knowing this information, how can green space planners, managers, and decision makers facilitate a better "fit" between people and nature in urban...

Moral Spaces in MySpace: Preservice Teachers' Perspectives about Ethical Issues in Social Networking

ERIC Educational Resources Information Center

Foulger, Teresa S.; Ewbank, Ann Dutton; Kay, Adam; Popp, Sharon Osborn; Carter, Heather Lynn

2009-01-01

MySpace and Facebook are innovative digital communication tools that surpass traditional means of social interaction. However, in some instances in which educators have used these tools, public reactions to them have resulted in sanctions. With the notion that traditional ideas of privacy and teacher conduct are not yet defined in online worlds,…

"Rise Up!": Literacies, Lived Experiences, and Identities within an In-School "Other Space"

ERIC Educational Resources Information Center

Wissman, Kelly K.

2011-01-01

In this article, I consider the literacy practices that emerged in an in-school elective course centered in the literacy tradition of African American women. Drawing from spatial perspectives (Leander& Sheehy, 2004), I explore what it means to consider this course an "Other space" (Foucault,1986), as a space created without the constraints of a…

Field Theoretical Methods in Cosmology

NASA Astrophysics Data System (ADS)

Singh, Anupam

1995-01-01

To optimally utilize all the exciting cosmological data coming in we need to sharpen also the theoretical tools available to cosmologists. One such indispensible tool to understand hot big bang cosmology is finite temperature field theory. We review and summarise the efforts made by us to use finite temperature field theory to address issues of current interest to cosmologists. An introduction to both the real time and the imaginary time formalisms is provided. The imaginary time formalism is illustrated by applying it to understand the interesting possibility of late Time Phase Transitions. Recent observations of the space distribution of quasars indicate a very notable peak in space density at a redshift of 2 to 3. It is pointed out that this may be the result of a phase transition which has a critical temperature of roughly a few meV (in the cosmological units, h = c = k = 1), which is natural in the context of massive neutrinos. In fact, the neutrino masses required for quasar production and those required to solve the solar neutrino problem by the MSW mechanism are consistent with each other. As a bonus, the cosmological constant implied by this model may also help resolve the discrepancy between the recently measured value of the Hubble Constant and the age of the universe. We illustrate the real time formalism by studying one of the most important time-dependent and non-equilibrium phenomena associated with phase transitions. The non-equilibrium dynamics of the first stage of the reheating process, that is dissipation via particle production is studied in scalar field theories. We show that a complete understanding of the mechanism of dissipation via particle production requires a non-perturbative resummation. We then study a Hartree approximation and clearly exhibit dissipative effects related to particle production. The effect of dissipation by Goldstone bosons is studied non-perturbatively in the large N limit in an O(N) theory. We also place our work in perspective and point out some of the related issues which clearly need further exploration.

Potential pressurized payloads: Fluid and thermal experiments

NASA Technical Reports Server (NTRS)

Swanson, Theodore D.

1992-01-01

Space Station Freedom (SSF) presents the opportunity to perform long term fluid and thermal experiments in a microgravity environment. This presentation provides perspective on the need for fluids/thermal experimentation in a microgravity environment, addresses previous efforts, identifies possible experiments, and discusses the capabilities of a proposed fluid physics/dynamics test facility. Numerous spacecraft systems use fluids for their operation. Thermal control, propulsion, waste management, and various operational processes are examples of such systems. However, effective ground testing is very difficult. This is because the effect of gravity induced phenomena, such as hydrostatic pressure, buoyant convection, and stratification, overcome such forces as surface tension, diffusion, electric potential, etc., which normally dominate in a microgravity environment. Hence, space experimentation is necessary to develop and validate a new fluid based technology. Two broad types of experiments may be performed on SSF: basic research and applied research. Basic research might include experiments focusing on capillary phenomena (with or without thermal and/or solutal gradients), thermal/solutal convection, phase transitions, and multiphase flow. Representative examples of applied research might include two-phase pressure drop, two-phase flow instabilities, heat transfer coefficients, fluid tank fill/drain, tank slosh dynamics, condensate removal enhancement, and void formation within thermal energy storage materials. In order to better support such fluid/thermal experiments on board SSF, OSSA has developed a conceptual design for a proposed Fluid Physics/Dynamics Facility (FP/DF). The proposed facility consists of one facility rack permanently located on SSF and one experimenter rack which is changed out as needed to support specific experiments. This approach will minimize the on-board integration/deintegration required for specific experiments. The FP/DF will have acceleration/vibration compensation, power and thermal interfaces, computer command/data collection, a video imaging system, and a portable glove box for operations. This facility will allow real-time astronaut interaction with the testing.

Perspectives from space: NASA classroom information and activities

NASA Technical Reports Server (NTRS)

1992-01-01

This booklet contains the information and classroom activities included on the backs of the eight poster series, 'Perspectives From Space'. The first series, Earth, An Integrated System, contains information on global ecology, remote sensing from space, data products, earth modeling, and international environmental treaties. The second series, Patterns Among Planets, contains information on the solar system, planetary processes, impacts and atmospheres, and a classroom activity on Jupiter's satellite system. The third series, Our Place In The Cosmos, contains information on the scale of the universe, origins of the universe, mission to the universe, and three classroom activities. The fourth series, Our Sun, The Nearest Star, contains information on the Sun. The fifth series, Oasis Of Life, contains information on the development of life, chemical and biological evolution on Earth and the search for other life in the universe. The sixth series, The Influence Of Gravity, contains information on Newton's Law of Gravity, space and microgravity, microgravity environment, and classroom activities on gravity. The seventh series, The Spirit Of Exploration, contains information on space exploration, the Apollo Program, future exploration activities, and two classroom activities. The eighth series, Global Cooperation, contains information on rocketry, the space race, and multi-nation exploration projects.

Earned Value Management Considering Technical Readiness Level and Its Application to New Space Launcher Program

NASA Astrophysics Data System (ADS)

Choi, Young-In; Ahn, Jaemyung

2018-04-01

Earned value management (EVM) is a methodology for monitoring and controlling the performance of a project based on a comparison between planned and actual cost/schedule. This study proposes a concept of hybrid earned value management (H-EVM) that integrates the traditional EVM metrics with information on the technology readiness level. The proposed concept can reflect the progress of a project in a sensitive way and provides short-term perspective complementary to the traditional EVM metrics. A two-dimensional visualization on the cost/schedule status of a project reflecting both of the traditional EVM (long-term perspective) and the proposed H-EVM (short-term perspective) indices is introduced. A case study on the management of a new space launch vehicle development program is conducted to demonstrate the effectiveness of the proposed H-EVM concept, associated metrics, and the visualization technique.

From phase space to integrable representations and level-rank duality

NASA Astrophysics Data System (ADS)

Chattopadhyay, Arghya; Dutta, Parikshit; Dutta, Suvankar

2018-05-01

We explicitly find representations for different large N phases of Chern-Simons matter theory on S 2 × S 1. These representations are characterised by Young diagrams. We show that no-gap and lower-gap phase of Chern-Simons-matter theory correspond to integrable representations of SU( N) k affine Lie algebra, where as upper-cap phase corresponds to integrable representations of SU( k - N) k affine Lie algebra. We use phase space description of [1] to obtain these representations and argue how putting a cap on eigenvalue distribution forces corresponding representations to be integrable. We also prove that the Young diagrams corresponding to lower-gap and upper-cap representations are related to each other by transposition under level-rank duality. Finally we draw phase space droplets for these phases and show how information about eigenvalue and Young diagram descriptions can be captured in topologies of these droplets in a unified way.

Space Station Freedom - A resource for aerospace education

NASA Technical Reports Server (NTRS)

Brown, Robert W.

1988-01-01

The role of the International Space Station in future U.S. aerospace education efforts is discussed from a NASA perspective. The overall design concept and scientific and technological goals of the Space Station are reviewed, and particular attention is given to education projects such as the Davis Planetarium Student Space Station, the Starship McCullough, the Space Habitat, the working Space Station model in Austin, TX, the Challenger Center for Space Life Education, Space M+A+X, and the Space Science Student Involvement Program. Also examined are learning-theory aspects of aerospace education: child vs adult learners, educational objectives, teaching methods, and instructional materials.

Perspectives of Light-Front Quantized Field Theory: Some New Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Srivastava, Prem P.

1999-08-13

A review of some basic topics in the light-front (LF) quantization of relativistic field theory is made. It is argued that the LF quantization is equally appropriate as the conventional one and that they lead, assuming the microcausality principle, to the same physical content. This is confirmed in the studies on the LF of the spontaneous symmetry breaking (SSB), of the degenerate vacua in Schwinger model (SM) and Chiral SM (CSM), of the chiral boson theory, and of the QCD in covariant gauges among others. The discussion on the LF is more economical and more transparent than that found inmore » the conventional equal-time quantized theory. The removal of the constraints on the LF phase space by following the Dirac method, in fact, results in a substantially reduced number of independent dynamical variables. Consequently, the descriptions of the physical Hilbert space and the vacuum structure, for example, become more tractable. In the context of the Dyson-Wick perturbation theory the relevant propagators in the front form theory are causal. The Wick rotation can then be performed to employ the Euclidean space integrals in momentum space. The lack of manifest covariance becomes tractable, and still more so if we employ, as discussed in the text, the Fourier transform of the fermionic field based on a special construction of the LF spinor. The fact that the hyperplanes x{sup {+-}} = 0 constitute characteristic surfaces of the hyperbolic partial differential equation is found irrelevant in the quantized theory; it seems sufficient to quantize the theory on one of the characteristic hyperplanes.« less

Signal Strength-Based Global Navigation Satellite System Performance Assessment in the Space Service Volume

NASA Technical Reports Server (NTRS)

Welch, Bryan W.

2016-01-01

NASA is participating in the International Committee on Global Navigation Satellite Systems (GNSS) (ICG)'s efforts towards demonstrating the benefits to the space user in the Space Service Volume (SSV) when a multi-GNSS solution space approach is utilized. The ICG Working Group: Enhancement of GNSS Performance, New Services and Capabilities has started a three phase analysis initiative as an outcome of recommendations at the ICG-10 meeting, in preparation for the ICG-11 meeting. The second phase of that increasing complexity and fidelity analysis initiative is based on augmenting the Phase 1 pure geometrical approach with signal strength-based limitations to determine if access is valid. The second phase of analysis has been completed, and the results are documented in this paper.

The nexus between climate change, ecosystem services and human health: Towards a conceptual framework.

PubMed

Chiabai, Aline; Quiroga, Sonia; Martinez-Juarez, Pablo; Higgins, Sahran; Taylor, Tim

2018-09-01

This paper addresses the impact that changes in natural ecosystems can have on health and wellbeing focusing on the potential co-benefits that green spaces could provide when introduced as climate change adaptation measures. Ignoring such benefits could lead to sub-optimal planning and decision-making. A conceptual framework, building on the ecosystem-enriched Driver, Pressure, State, Exposure, Effect, Action model (eDPSEEA), is presented to aid in clarifying the relational structure between green spaces and human health, taking climate change as the key driver. The study has the double intention of (i) summarising the literature with a special emphasis on the ecosystem and health perspectives, as well as the main theories behind these impacts, and (ii) modelling these findings into a framework that allows for multidisciplinary approaches to the underlying relations between human health and green spaces. The paper shows that while the literature based on the ecosystem perspective presents a well-documented association between climate, health and green spaces, the literature using a health-based perspective presents mixed evidence in some cases. The role of contextual factors and the exposure mechanism are rarely addressed. The proposed framework could serve as a multidisciplinary knowledge platform for multi-perspecitve analysis and discussion among experts and stakeholders, as well as to support the operationalization of quantitative assessment and modelling exercises. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Streamlined design and self reliant hardware for active control of precision space structures

NASA Technical Reports Server (NTRS)

Hyland, David C.; King, James A.; Phillips, Douglas J.

1994-01-01

Precision space structures may require active vibration control to satisfy critical performance requirements relating to line-of-sight pointing accuracy and the maintenance of precise, internal alignments. In order for vibration control concepts to become operational, it is necessary that their benefits be practically demonstrated in large scale ground-based experiments. A unique opportunity to carry out such demonstrations on a wide variety of experimental testbeds was provided by the NASA Control-Structure Integration (CSI) Guest Investigator (GI) Program. This report surveys the experimental results achieved by the Harris Corporation GI team on both Phases 1 and 2 of the program and provides a detailed description of Phase 2 activities. The Phase 1 results illustrated the effectiveness of active vibration control for space structures and demonstrated a systematic methodology for control design, implementation test. In Phase 2, this methodology was significantly streamlined to yield an on-site, single session design/test capability. Moreover, the Phase 2 research on adaptive neural control techniques made significant progress toward fully automated, self-reliant space structure control systems. As a further thrust toward productized, self-contained vibration control systems, the Harris Phase II activity concluded with experimental demonstration of new vibration isolation hardware suitable for a wide range of space-flight and ground-based commercial applications.The CSI GI Program Phase 1 activity was conducted under contract NASA1-18872, and the Phase 2 activity was conducted under NASA1-19372.

Practical Application of PRA as an Integrated Design Tool for Space Systems

NASA Technical Reports Server (NTRS)

Kalia, Prince; Shi, Ying; Pair, Robin; Quaney, Virginia; Uhlenbrock, John

2013-01-01

This paper presents the application of the first comprehensive Probabilistic Risk Assessment (PRA) during the design phase of a joint NASA/NOAA weather satellite program, Geostationary Operational Environmental Satellite Series R (GOES-R). GOES-R is the next generation weather satellite primarily to help understand the weather and help save human lives. PRA has been used at NASA for Human Space Flight for many years. PRA was initially adopted and implemented in the operational phase of manned space flight programs and more recently for the next generation human space systems. Since its first use at NASA, PRA has become recognized throughout the Agency as a method of assessing complex mission risks as part of an overall approach to assuring safety and mission success throughout project lifecycles. PRA is now included as a requirement during the design phase of both NASA next generation manned space vehicles as well as for high priority robotic missions. The influence of PRA on GOES-R design and operation concepts are discussed in detail. The GOES-R PRA is unique at NASA for its early implementation. It also represents a pioneering effort to integrate risks from both Spacecraft (SC) and Ground Segment (GS) to fully assess the probability of achieving mission objectives. PRA analysts were actively involved in system engineering and design engineering to ensure that a comprehensive set of technical risks were correctly identified and properly understood from a design and operations perspective. The analysis included an assessment of SC hardware and software, SC fault management system, GS hardware and software, common cause failures, human error, natural hazards, solar weather and infrastructure (such as network and telecommunications failures, fire). PRA findings directly resulted in design changes to reduce SC risk from micro-meteoroids. PRA results also led to design changes in several SC subsystems, e.g. propulsion, guidance, navigation and control (GNC), communications, mechanisms, and command and data handling (C&DH). The fault tree approach assisted in the development of the fault management system design. Human error analysis, which examined human response to failure, indicated areas where automation could reduce the overall probability of gaps in operation by half. In addition, the PRA brought to light many potential root causes of system disruptions, including earthquakes, inclement weather, solar storms, blackouts and other extreme conditions not considered in the typical reliability and availability analyses. Ultimately the PRA served to identify potential failures that, when mitigated, resulted in a more robust design, as well as to influence the program's concept of operations. The early and active integration of PRA with system and design engineering provided a well-managed approach for risk assessment that increased reliability and availability, optimized lifecyc1e costs, and unified the SC and GS developments.

Diffeomorphisms as symplectomorphisms in history phase space: Bosonic string model

NASA Astrophysics Data System (ADS)

Kouletsis, I.; Kuchař, K. V.

2002-06-01

The structure of the history phase space G of a covariant field system and its history group (in the sense of Isham and Linden) is analyzed on an example of a bosonic string. The history space G includes the time map T from the spacetime manifold (the two-sheet) Y to a one-dimensional time manifold T as one of its configuration variables. A canonical history action is posited on G such that its restriction to the configuration history space yields the familiar Polyakov action. The standard Dirac-ADM action is shown to be identical with the canonical history action, the only difference being that the underlying action is expressed in two different coordinate charts on G. The canonical history action encompasses all individual Dirac-ADM actions corresponding to different choices T of foliating Y. The history Poisson brackets of spacetime fields on G induce the ordinary Poisson brackets of spatial fields in the instantaneous phase space G0 of the Dirac-ADM formalism. The canonical history action is manifestly invariant both under spacetime diffeomorphisms Diff Y and temporal diffeomorphisms Diff T. Both of these diffeomorphisms are explicitly represented by symplectomorphisms on the history phase space G. The resulting classical history phase space formalism is offered as a starting point for projection operator quantization and consistent histories interpretation of the bosonic string model.

The Many Dimensions of Program Management

NASA Technical Reports Server (NTRS)

Dean, Edwin B.

1992-01-01

For the purposes of this paper, program refers to a collection of activities or projects which must be performed according to a plan or schedule. The Space Exploration Initiative within the National Aeronautics and Space Administration (NASA) is an example. Dimensionality refers to both the various perspectives of a program and to the components within that perspective. It is, thus, appropriate to think of dimensions of dimensionality. For example, one dimension or perspective of a program is the projects which perform the program. Within the project dimension, the individual projects are the components of that dimensionality. The number of projects defines the spatial dimensionality of the project dimension. Thus, each perspective or dimension has a dimensionality of its own. The structure and associated values of all the various perspectives of a program define the program. A project refers to the collection of activities required to conceive, sell, design, develop, evaluate, produce, operate, support, evolve, and retire a given system. A project thus effects the life cycle of given system. A project is, thus, the system to conceive, sell, design, develop, evaluate, produce, operate, support, evolve, and retire a system. A program, thus, effects the life cycle of the collection of projects required to effect the collection of systems required to implement the program.

Implications of acceleration environments on scaling materials processing in space to production

NASA Technical Reports Server (NTRS)

Demel, Ken

1990-01-01

Some considerations regarding materials processing in space are covered from a commercial perspective. Key areas include power, proprietary data, operational requirements (including logistics), and also the center of gravity location, and control of that location with respect to materials processing payloads.

The James Webb Space Telescope Integrated Science Instrument Module

NASA Technical Reports Server (NTRS)

Greenhouse, Matthew A.; Sullivan, Pamela C.; Boyce, Leslye A.; Glazer, Stuart D.; Johnson, Eric L.; McCloskey, John C.; Voyton, Mark F.

2004-01-01

The Integrated Science Instrument Module of the James Webb Space Telescope is described from a systems perspective with emphasis on unique and advanced technology aspects. The major subsystems of this flight element are described including: structure, thermal, command and data handling, and software.

AIR EMISSIONS FROM RESIDENTIAL HEATING: THE WOOD HEATING OPTION PUT INTO ENVIRONMENTAL PERSPECTIVE

EPA Science Inventory

The paper compares the national scale (rather than local) air quality impacts of the various residential space heating options. Specifically, it compares the relative contribution of the space heating options to fine particulate emissions, greenhouse gas emissions, and acid preci...

Hearing on Space Situational Awareness:

NASA Image and Video Library

2018-06-22

Commander, U.S. Strategic Command, General John Hyten testifies before the House Subcommittee on Strategic Forces during a hearing on Space Situational Awareness: Whole of Government Perspectives on Roles and Responsibilities, Friday, June 22, 2018 at the Rayburn House Office Building in Washington. Photo Credit: (NASA/Bill Ingalls)

Hearing on Space Situational Awareness:

NASA Image and Video Library

2018-06-22

Secretary of Commerce Wilbur Ross prepares to testify before the House Subcommittee on Strategic Forces during a hearing on Space Situational Awareness: Whole of Government Perspectives on Roles and Responsibilities, Friday, June 22, 2018 at the Rayburn House Office Building in Washington. Photo Credit: (NASA/Bill Ingalls)

Campaign-level dynamic network modelling for spaceflight logistics for the flexible path concept

NASA Astrophysics Data System (ADS)

Ho, Koki; de Weck, Olivier L.; Hoffman, Jeffrey A.; Shishko, Robert

2016-06-01

This paper develops a network optimization formulation for dynamic campaign-level space mission planning. Although many past space missions have been designed mainly from a mission-level perspective, a campaign-level perspective will be important for future space exploration. In order to find the optimal campaign-level space transportation architecture, a mixed-integer linear programming (MILP) formulation with a generalized multi-commodity flow and a time-expanded network is developed. Particularly, a new heuristics-based method, a partially static time-expanded network, is developed to provide a solution quickly. The developed method is applied to a case study containing human exploration of a near-Earth object (NEO) and Mars, related to the concept of the Flexible Path. The numerical results show that using the specific combinations of propulsion technologies, in-situ resource utilization (ISRU), and other space infrastructure elements can reduce the initial mass in low-Earth orbit (IMLEO) significantly. In addition, the case study results also show that we can achieve large IMLEO reduction by designing NEO and Mars missions together as a campaign compared with designing them separately owing to their common space infrastructure pre-deployment. This research will be an important step toward efficient and flexible campaign-level space mission planning.

Asking to Listen: Towards a Youth Perspective on Sexual Health Education and Needs

ERIC Educational Resources Information Center

MacDonald, Jo-Ann; Gagnon, Anita J.; Mitchell, Claudia; Di Meglio, Giuseppina; Rennick, Janet E.; Cox, Joseph

2011-01-01

In this three-phase exploratory study, we used participatory approaches with youth in a small Canadian province. Through iterative focus groups in school settings, we examined young men and women's perspectives regarding factors important to taking control of their sexual health behaviour. Youth aged 15-17 discussed sexual health through…

Community Development: A Quiet Evolution from Rhodesia to Zimbabwe.

ERIC Educational Resources Information Center

Madondo, B. B. S.

1985-01-01

Because of the importance of community development in development strategies, both in Rhodesia and, more recently, Zimbabwe, this article looks at the concept in a historical perspective. In this perspective, three major phases can be identified: the period between 1890 and 1962; the period between 1962 and 1979; and 1980 to the present. (CT)

Phase space holes and synchronized BGK modes in autoresonantly driven, Penning-trapped electron clouds

NASA Astrophysics Data System (ADS)

Friedland, Lazar; Fajans, Joel; Bertsche, Will; Wurtele, Jonathan

2003-10-01

We study excitation and control of BGK modes in pure electron plasmas in a Penning trap. We apply an oscillating external potential with a negatively chirped frequency. This drive resonates with, and phase-locks to, a group of axially bouncing electrons in the trap. All initially phase-locked electrons remain phase-locked during the chirp (the autoresonance phenomenon), while some new particles are added to the resonant group, as the bucket moves through the phase space. This creates an oscillating in space and slowly evolving in energy hole in the phase space distribution of the electrons. The electron density perturbation associated with this evolving hole yields a BGK mode synchronized with the drive. The local depth of the hole in phase space, and, thus, the amplitude of the mode are controlled by the external parameter (the driving frequency). The process is reversible, so that the BGK mode can be returned to its nearly initial state, by reversing the direction of variation of the driving frequency. A kinetic theory of this excitation process is developed. The theory uses results on passage through, and capture into, bounce resonance in the system from Monte Carlo simulations of resonant bucket dynamics. We discuss the dependence of the excited BGK mode on the drive frequency chirp rate and other plasma parameters and compare these predictions with experiments.

How Long Can the Hubble Space Telescope Operate Reliably? A Total Dose Perspective

NASA Technical Reports Server (NTRS)

Xapsos, M. A.; Stauffer, C.; Jordan, T.; Poivey, C.; Haskins, D. N.; Lum, G.; Pergosky, A. M.; Smith, D. C.; LaBel, K. A.

2014-01-01

The Hubble Space Telescope has been at the forefront of discoveries in the field of astronomy for more than 20 years. It was the first telescope designed to be serviced in space and the last such servicing mission occurred in May 2009. The question of how much longer this valuable resource can continue to return science data remains. In this paper a detailed analysis of the total dose exposure of electronic parts at the box level is performed using solid angle sectoring/3-dimensional ray trace and Monte Carlo radiation transport simulations. Results are related to parts that have been proposed as possible total dose concerns. The spacecraft subsystem that appears to be at the greatest risk for total dose failure is identified. This is discussed with perspective on the overall lifetime of the spacecraft.

Spaced-antenna wind estimation using an X-band active phased-array weather radar

NASA Astrophysics Data System (ADS)

Venkatesh, Vijay

Over the past few decades, several single radar methods have been developed to probe the kinematic structure of storms. All these methods trade angular-resolution to retrieve the wind-field. To date, the spaced-antenna method has been employed for profiling the ionosphere and the precipitation free lower atmosphere. This work focuses on applying the spaced-antenna method on an X-band active phased-array radar for high resolution horizontal wind-field retrieval from precipitation echoes. The ability to segment the array face into multiple displaced apertures allows for flexible spaced-antenna implementations. The methodology employed herein comprises of Monte-Carlo simulations to optimize the spaced-antenna system design and analysis of real data collected with the designed phased-array system. The contribution that underpins this dissertation is the demonstration of qualitative agreement between spaced-antenna and Doppler beam swinging retrievals based on real data. First, simulations of backscattered electric fields at the antenna array elements are validated using theoretical expressions. Based on the simulations, the degrees of freedom in the spaced-antenna system design are optimized for retrieval of mean baseline wind. We show that the designed X-band spaced-antenna system has lower retrieval uncertainty than the existing S-band spaced-antenna implementation on the NWRT. This is because of the flexibility to synthesize small overlapping apertures and the ability to obtain statistically independent samples at a faster rate at X-band. We then demonstrate a technique to make relative phase-center displacement measurements based on simulations and real data from the phased-array spaced-antenna system. This simple method uses statistics of precipitation echoes and apriori beamwidth measurements to make field repeatable phase-center displacement measurements. Finally, we test the hypothesis that wind-field curvature effects are common to both the spaced-antenna and Doppler beam swinging methods. Based on a close-range winter storm data set, we find that the spaced-antenna and fine-resolution Doppler beam swinging retrievals are in qualitative agreement. The correlation between the spaced-antenna and fine-resolution Doppler beam swinging retrievals was 0.57. The lowered correlation coefficient was, in part, due to the high standard deviation of the DBS retrievals. At high wind-speeds, the spaced-antenna retrievals significantly departed from variational retrievals of mean baseline wind.

International Space Station (ISS)

NASA Image and Video Library

1995-04-17

This computer generated scene of the International Space Station (ISS) represents the first addition of hardware following the completion of Phase II. The 8-A Phase shows the addition of the S-9 truss.

Spiral computed tomography phase-space source model in the BEAMnrc/EGSnrc Monte Carlo system: implementation and validation.

PubMed

Kim, Sangroh; Yoshizumi, Terry T; Yin, Fang-Fang; Chetty, Indrin J

2013-04-21

Currently, the BEAMnrc/EGSnrc Monte Carlo (MC) system does not provide a spiral CT source model for the simulation of spiral CT scanning. We developed and validated a spiral CT phase-space source model in the BEAMnrc/EGSnrc system. The spiral phase-space source model was implemented in the DOSXYZnrc user code of the BEAMnrc/EGSnrc system by analyzing the geometry of spiral CT scan-scan range, initial angle, rotational direction, pitch, slice thickness, etc. Table movement was simulated by changing the coordinates of the isocenter as a function of beam angles. Some parameters such as pitch, slice thickness and translation per rotation were also incorporated into the model to make the new phase-space source model, designed specifically for spiral CT scan simulations. The source model was hard-coded by modifying the 'ISource = 8: Phase-Space Source Incident from Multiple Directions' in the srcxyznrc.mortran and dosxyznrc.mortran files in the DOSXYZnrc user code. In order to verify the implementation, spiral CT scans were simulated in a CT dose index phantom using the validated x-ray tube model of a commercial CT simulator for both the original multi-direction source (ISOURCE = 8) and the new phase-space source model in the DOSXYZnrc system. Then the acquired 2D and 3D dose distributions were analyzed with respect to the input parameters for various pitch values. In addition, surface-dose profiles were also measured for a patient CT scan protocol using radiochromic film and were compared with the MC simulations. The new phase-space source model was found to simulate the spiral CT scanning in a single simulation run accurately. It also produced the equivalent dose distribution of the ISOURCE = 8 model for the same CT scan parameters. The MC-simulated surface profiles were well matched to the film measurement overall within 10%. The new spiral CT phase-space source model was implemented in the BEAMnrc/EGSnrc system. This work will be beneficial in estimating the spiral CT scan dose in the BEAMnrc/EGSnrc system.

Spiral computed tomography phase-space source model in the BEAMnrc/EGSnrc Monte Carlo system: implementation and validation

NASA Astrophysics Data System (ADS)

Kim, Sangroh; Yoshizumi, Terry T.; Yin, Fang-Fang; Chetty, Indrin J.

2013-04-01

Currently, the BEAMnrc/EGSnrc Monte Carlo (MC) system does not provide a spiral CT source model for the simulation of spiral CT scanning. We developed and validated a spiral CT phase-space source model in the BEAMnrc/EGSnrc system. The spiral phase-space source model was implemented in the DOSXYZnrc user code of the BEAMnrc/EGSnrc system by analyzing the geometry of spiral CT scan—scan range, initial angle, rotational direction, pitch, slice thickness, etc. Table movement was simulated by changing the coordinates of the isocenter as a function of beam angles. Some parameters such as pitch, slice thickness and translation per rotation were also incorporated into the model to make the new phase-space source model, designed specifically for spiral CT scan simulations. The source model was hard-coded by modifying the ‘ISource = 8: Phase-Space Source Incident from Multiple Directions’ in the srcxyznrc.mortran and dosxyznrc.mortran files in the DOSXYZnrc user code. In order to verify the implementation, spiral CT scans were simulated in a CT dose index phantom using the validated x-ray tube model of a commercial CT simulator for both the original multi-direction source (ISOURCE = 8) and the new phase-space source model in the DOSXYZnrc system. Then the acquired 2D and 3D dose distributions were analyzed with respect to the input parameters for various pitch values. In addition, surface-dose profiles were also measured for a patient CT scan protocol using radiochromic film and were compared with the MC simulations. The new phase-space source model was found to simulate the spiral CT scanning in a single simulation run accurately. It also produced the equivalent dose distribution of the ISOURCE = 8 model for the same CT scan parameters. The MC-simulated surface profiles were well matched to the film measurement overall within 10%. The new spiral CT phase-space source model was implemented in the BEAMnrc/EGSnrc system. This work will be beneficial in estimating the spiral CT scan dose in the BEAMnrc/EGSnrc system.

Compactification on phase space

NASA Astrophysics Data System (ADS)

Lovelady, Benjamin; Wheeler, James

2016-03-01

A major challenge for string theory is to understand the dimensional reduction required for comparison with the standard model. We propose reducing the dimension of the compactification by interpreting some of the extra dimensions as the energy-momentum portion of a phase-space. Such models naturally arise as generalized quotients of the conformal group called biconformal spaces. By combining the standard Kaluza-Klein approach with such a conformal gauge theory, we may start from the conformal group of an n-dimensional Euclidean space to form a 2n-dimensional quotient manifold with symplectic structure. A pair of involutions leads naturally to two n-dimensional Lorentzian manifolds. For n = 5, this leaves only two extra dimensions, with a countable family of possible compactifications and an SO(5) Yang-Mills field on the fibers. Starting with n=6 leads to 4-dimensional compactification of the phase space. In the latter case, if the two dimensions each from spacetime and momentum space are compactified onto spheres, then there is an SU(2)xSU(2) (left-right symmetric electroweak) field between phase and configuration space and an SO(6) field on the fibers. Such a theory, with minor additional symmetry breaking, could contain all parts of the standard model.

Wigner functions for evanescent waves.

PubMed

Petruccelli, Jonathan C; Tian, Lei; Oh, Se Baek; Barbastathis, George

2012-09-01

We propose phase space distributions, based on an extension of the Wigner distribution function, to describe fields of any state of coherence that contain evanescent components emitted into a half-space. The evanescent components of the field are described in an optical phase space of spatial position and complex-valued angle. Behavior of these distributions upon propagation is also considered, where the rapid decay of the evanescent components is associated with the exponential decay of the associated phase space distributions. To demonstrate the structure and behavior of these distributions, we consider the fields generated from total internal reflection of a Gaussian Schell-model beam at a planar interface.

50th Anniversary Perspective: A Perspective on Polyelectrolyte Solutions

PubMed Central

2017-01-01

From the beginning of life with the information-containing polymers until the present era of a plethora of water-based materials in health care industry and biotechnology, polyelectrolytes are ubiquitous with a broad range of structural and functional properties. The main attribute of polyelectrolyte solutions is that all molecules are strongly correlated both topologically and electrostatically in their neutralizing background of charged ions in highly polarizable solvent. These strong correlations and the necessary use of numerous variables in experiments on polyelectrolytes have presented immense challenges toward fundamental understanding of the various behaviors of charged polymeric systems. This Perspective presents the author’s subjective summary of several conceptual advances and the remaining persistent challenges in the contexts of charge and size of polymers, structures in homogeneous solutions, thermodynamic instability and phase transitions, structural evolution with oppositely charged polymers, dynamics in polyelectrolyte solutions, kinetics of phase separation, mobility of charged macromolecules between compartments, and implications to biological systems. PMID:29296029

Molecular quantum control landscapes in von Neumann time-frequency phase space

NASA Astrophysics Data System (ADS)

Ruetzel, Stefan; Stolzenberger, Christoph; Fechner, Susanne; Dimler, Frank; Brixner, Tobias; Tannor, David J.

2010-10-01

Recently we introduced the von Neumann representation as a joint time-frequency description for femtosecond laser pulses and suggested its use as a basis for pulse shaping experiments. Here we use the von Neumann basis to represent multidimensional molecular control landscapes, providing insight into the molecular dynamics. We present three kinds of time-frequency phase space scanning procedures based on the von Neumann formalism: variation of intensity, time-frequency phase space position, and/or the relative phase of single subpulses. The shaped pulses produced are characterized via Fourier-transform spectral interferometry. Quantum control is demonstrated on the laser dye IR140 elucidating a time-frequency pump-dump mechanism.

Molecular quantum control landscapes in von Neumann time-frequency phase space.

PubMed

Ruetzel, Stefan; Stolzenberger, Christoph; Fechner, Susanne; Dimler, Frank; Brixner, Tobias; Tannor, David J

2010-10-28

Recently we introduced the von Neumann representation as a joint time-frequency description for femtosecond laser pulses and suggested its use as a basis for pulse shaping experiments. Here we use the von Neumann basis to represent multidimensional molecular control landscapes, providing insight into the molecular dynamics. We present three kinds of time-frequency phase space scanning procedures based on the von Neumann formalism: variation of intensity, time-frequency phase space position, and/or the relative phase of single subpulses. The shaped pulses produced are characterized via Fourier-transform spectral interferometry. Quantum control is demonstrated on the laser dye IR140 elucidating a time-frequency pump-dump mechanism.

Marital satisfaction and depression among couples following men's acute coronary syndrome: testing dyadic dynamics in a longitudinal design.

PubMed

Dekel, Rachel; Vilchinsky, Noa; Liberman, Gabriel; Leibowitz, Morton; Khaskia, Abed; Mosseri, Morris

2014-05-01

The current study examined the contribution of marital satisfaction to symptoms of depression among patients with acute coronary syndrome (ACS) and their partners. The sample comprised of 91 ACS male patients and their female partners. Data were collected at the time of initial hospitalization and 6 months later. Patients' and partners' assessments of marital satisfaction were measured using the ENRICH scale. Symptoms of depression were measured using the Brief Symptoms Inventory (BSI). Dyadic analysis applying the Actor-Partner Inter-dependence Model (APIM) was used. Different patterns emerged for the two phases. In the acute phase, only the Actor effect was significant: for both patients and partners, one's greater marital satisfaction was associated with one's lower levels of depression. In the chronic phase, both Actor and Partner effects were significant, while different trends were found for patients and partners. Partners' marital satisfaction was associated with their own and the patients' decreased depression symptoms, whereas among patients, higher levels of marital satisfaction were associated with elevated levels of depression both for themselves and for their partners. A dyadic perspective and phases of illness have to be taken into account in understanding adjustment and developing interventions following ACS. What is already known on this subject? The contribution of marital satisfaction to psychological adjustment following cardiac illness has been explored, but mainly from the perspective of one partner only. Different phases of an illness present different challenges for both patients and family members. What does this study add? A dyadic perspective on recovery from cardiac illness. The partner's contribution during the different phases of the illness. © 2013 The British Psychological Society.

Propulsion Control Technology Development in the United States A Historical Perspective

NASA Technical Reports Server (NTRS)

Jaw, Link C.a; Garg, Sanjay

2005-01-01

This paper presents a historical perspective of the advancement of control technologies for aircraft gas turbine engines. The paper primarily covers technology advances in the United States in the last 60 years (1940 to approximately 2002). The paper emphasizes the pioneering technologies that have been tested or implemented during this period, assimilating knowledge and experience from industry experts, including personal interviews with both current and retired experts. Since the first United States-built aircraft gas turbine engine was flown in 1942, engine control technology has evolved from a simple hydro-mechanical fuel metering valve to a full-authority digital electronic control system (FADEC) that is common to all modern aircraft propulsion systems. At the same time, control systems have provided engine diagnostic functions. Engine diagnostic capabilities have also evolved from pilot observation of engine gauges to the automated on-board diagnostic system that uses mathematical models to assess engine health and assist in post-flight troubleshooting and maintenance. Using system complexity and capability as a measure, we can break the historical development of control systems down to four phases: (1) the start-up phase (1942 to 1949), (2) the growth phase (1950 to 1969), (3) the electronic phase (1970 to 1989), and (4) the integration phase (1990 to 2002). In each phase, the state-of-the-art control technology is described and the engines that have become historical landmarks, from the control and diagnostic standpoint, are identified. Finally, a historical perspective of engine controls in the last 60 years is presented in terms of control system complexity, number of sensors, number of lines of software (or embedded code), and other factors.

The fault monitoring and diagnosis knowledge-based system for space power systems: AMPERES, phase 1

NASA Technical Reports Server (NTRS)

Lee, S. C.

1989-01-01

The objective is to develop a real time fault monitoring and diagnosis knowledge-based system (KBS) for space power systems which can save costly operational manpower and can achieve more reliable space power system operation. The proposed KBS was developed using the Autonomously Managed Power System (AMPS) test facility currently installed at NASA Marshall Space Flight Center (MSFC), but the basic approach taken for this project could be applicable for other space power systems. The proposed KBS is entitled Autonomously Managed Power-System Extendible Real-time Expert System (AMPERES). In Phase 1 the emphasis was put on the design of the overall KBS, the identification of the basic research required, the initial performance of the research, and the development of a prototype KBS. In Phase 2, emphasis is put on the completion of the research initiated in Phase 1, and the enhancement of the prototype KBS developed in Phase 1. This enhancement is intended to achieve a working real time KBS incorporated with the NASA space power system test facilities. Three major research areas were identified and progress was made in each area. These areas are real time data acquisition and its supporting data structure; sensor value validations; development of inference scheme for effective fault monitoring and diagnosis, and its supporting knowledge representation scheme.

The space station assembly phase: Flight telerobotic servicer feasibility, volume 1

NASA Technical Reports Server (NTRS)

Smith, Jeffrey H.; Gyamfi, Max A.; Volkmer, Kent; Zimmerman, Wayne F.

1987-01-01

The question is addressed which was raised by the Critical Evaluation Task Force (CETF) analysis of the space station: if a Flight Telerobotic Servicer (FTS) of a given technical risk could be built for use during space station assembly, could it save significant extravehicular (EVA) resources. Key issues and trade-offs associated with using an FTS to aid in space station assembly phase tasks such as construction and servicing are identified. A methodology is presented that incorporates assessment of candidate assembly phase tasks, telerobotics performance capabilities, development costs, operational constraints (STS and proximity operations), maintenance, attached payloads, and polar platforms. A discussion of the issues is presented with focus on potential FTS roles: (1) as a research-oriented test bed to learn more about space usage of telerobotics; (2) as a research-based test bed with an experimental demonstration orientation and limited assembly and servicing applications; or (3) as an operational system to augment EVA, to aid the construction of the space station, and to reduce the programmatic (schedule) risk by increasing the flexibility of mission operations. During the course of the study, the baseline configuration was modified into Phase 1 (a station assembled in 12 flights), and Phase 2 (a station assembled over a 30 flight period) configuration.

Velocity Space Degrees of Freedom of Plasma Fluctuations

NASA Astrophysics Data System (ADS)

Mattingly, Sean

2017-10-01

Small scale wave modes are becoming more important in plasma physics. Examples include turbulent cascades in the solar wind, the energetics of fusion plasma electrostatic turbulence and transport, and low temperature basic plasma physics experiments. In order to improve our understanding of these modes, I present an advance in experimental plasma diagnostics and use it to show the first measurement of a plasma ion velocity-space cross-correlation matrix. From this matrix I determine the eigenmodes of fluctuations on the ion distribution function as a function of frequency. I also determine the relative strengths of these modes - these are the velocity space degrees of freedom of plasma fluctuations. This measurement can detect the aforementioned smaller scale modes in plasmas through a localized measurement. The locality of this measurement means that it may be applied to plasmas in which a single - point velocity sensitive diagnostic is available and multipoint measurements may be difficult. Examples include in situ measurements of space plasmas, fusion plasmas, trapped plasmas, and laser cooled plasmas. This fact, combined with the new perspective it can give on small scale plasma fluctuations, means it may be used to further research on the above cited subjects. Much work remains on fully understanding this measurement. This measurement opens a velocity space interpretation of small scale plasma wave modes, and understanding this perspective from theory requires the application or invention of new mathematical tools. I discuss open problems to follow up on, which include questions from experimental, theoretical, and instrumentation perspectives. NSF-DOE Program Grant DE-FG02-99ER54543.

Organisational Barriers for Women in Senior Management: A Comparison of Turkish and New Zealand Universities

ERIC Educational Resources Information Center

Neale, Jenny; Ozkanli, Ozlem

2010-01-01

This paper reports on the second phase of a multi-country study examining cross-cultural perspectives of gender and management in universities. The first phase of this research with eight countries found that the representation of women was consistently low, especially at Rector/Vice Chancellor level. In the second phase interviews were conducted…

Cost effective management of space venture risks

NASA Technical Reports Server (NTRS)

Giuntini, Ronald E.; Storm, Richard E.

1986-01-01

The development of a model for the cost-effective management of space venture risks is discussed. The risk assessment and control program of insurance companies is examined. A simplified system development cycle which consists of a conceptual design phase, a preliminary design phase, a final design phase, a construction phase, and a system operations and maintenance phase is described. The model incorporates insurance safety risk methods and reliability engineering, and testing practices used in the development of large aerospace and defense systems.

Space ventures and society long-term perspectives

NASA Technical Reports Server (NTRS)

Brown, W. M.

1985-01-01

A futuristic evaluation of mankind's potential long term future in space is presented. Progress in space will not be inhibited by shortages of the Earth's physical resources, since long term economic growth will be focused on ways to constrain industrial productivity by changing social values, management styles, or government competence. Future technological progress is likely to accelerate with an emphasis on international cooperation, making possible such large joint projects as lunar colonies or space stations on Mars. The long term future in space looks exceedingly bright even in relatively pessimistic scenarios. The principal driving forces will be technological progress, commercial and public-oriented satellites, space industrialization, space travel, and eventually space colonization.

Definition and preliminary design of the LAWS (Laser Atmospheric Wind Sounder). Volume 1, phase 2: Executive summary

NASA Technical Reports Server (NTRS)

1992-01-01

The objective of phase 1 of the LAWS study was to define and perform a preliminary design for the Laser Atmospheric Wind Sounder (LAWS) instrument. The definition phase consisted of identifying realistic concepts for LAWS and analyzing them in sufficient detail to be able to choose the most promising one for the LAWS application. System and subsystem configurations were then developed for the chosen concept. The concept and subsequent configurations were to be compatible with two prospective platforms--the Japanese Polar Orbiting Platform (JPOP) and as an attached payload on the Space Station Freedom. After a thorough and objective concept selection process, we chose a heterodyne detection Doppler lidar using a CO2 laser transmitter operating at 9.1 microns over a 2.1 micron solid state system. The choice of the CO2 approach over solid-state reflects the advanced state of development of CO2 lasers, its maturity in ground-based systems and the eased subsystem requirements associated with the longer wavelength. The CO2 lidar concept was then analyzed in detail to arrive at a configuration for the instrument and its major subsystems. Our approach throughout the configuration design was to take a systems perspective and trade requirements between subsystems, wherever possible, to arrive at configurations which made maximum use of existing, proven technology or relatively straightforward extensions to existing technology to reduce risk and cost. At the conclusion of Phase 1 we arrived at a configuration for LAWS which meets the performance requirements, yet which is less complex than previous designs of space-based wind sensors (e.g. Windsat), employs lightweight technologies to meet its weight goals (less than 800kg) and sufficiently flexible to offer various operational scenarios with power requirements from about 2 kW to 3 kW. The Phase 1 Final Report was released in March 1990. The 21-month Phase 2 began in October 1990. The requirement to accommodate LAWS as an attached payload on Space Station Freedom was deleted and the orbit altitude for the Japanese polar orbiting platform was changed from 824 km to 705 km. The power allocated to LAWS was reduced to 2.2 kW from 3 kW. Subsequently the availability of a Japanese Polar Orbiting Platform was called into question and LAWS accommodation studies were continued using a conceptual, ATLAS-launched platform supplied by MSFC. In March 1991 a modification to the original contracts was funded to provide a LAWS laser breadboard which could demonstrate all the performance requirements of the LAWS laser. Also funded as part of the same contract extension was a lifetest demonstration using an existing laser at STI. The breadboard extension was an eighteen month effort and the period of performance was therefore extended to September 30, 1992.

TRW Video News: Chandra X-ray Observatory

NASA Technical Reports Server (NTRS)

1999-01-01

This NASA Kennedy Space Center sponsored video release presents live footage of the Chandra X-ray Observatory prior to STS-93 as well as several short animations recreating some of its activities in space. These animations include a Space Shuttle fly-by with Chandra, two perspectives of Chandra's deployment from the Shuttle, the Chandra deployment orbit sequence, the Initial Upper Stage (IUS) first stage burn, and finally a "beauty shot", which represents another animated view of Chandra in space.

Manned spaceflight in the nineties: The European perspective

NASA Technical Reports Server (NTRS)

Finke, W.

1985-01-01

The inaugural speech for the international space travel symposium which took place in Bad Godesberg, West Germany on 2 Oct. 1985 explains why Europe must take an active part in all aspects of manned space travel for the nineties, including the development of the space station itself and the development of its own reusable space transport and supporting ground equipment to proceed on an equal share basis with the US and Japan while maintaining close international cooperation.

Analysing Finnish Steering System from the Perspective of Social Space: The Case of the "Campus University"

ERIC Educational Resources Information Center

Treuthardt, Leena; Valimaa, Jussi

2008-01-01

The present study analyses Finnish higher education steering system, management by results, from the perspective of higher education institutions. We ask what happens inside a higher education institution, called here the "Campus University", during the actual negotiations related to the national steering system. We analyse not only the…

Feminist Scholarship: Cross-Disciplinary Connections for Cultivating a Critical Perspective in Kinesiology

ERIC Educational Resources Information Center

Reifsteck, Erin J.

2014-01-01

Kinesiology has not been a particularly inviting space for feminist critical analysis. In this article, as a graduate student in the field, I argue that feminist scholarship from women and gender studies can be applied to kinesiology issues to promote a critical perspective that is often missing in kinesiology. I draw connections between feminist…

Distinctive Features of Spatial Perspective-Taking in the Elderly

ERIC Educational Resources Information Center

Watanabe, Masayuki

2011-01-01

This study aimed to ascertain the characteristics of spatial perspective-taking ability--assumed to be a form of imaginary body movement in three-dimensional space--in the elderly. A new task was devised to evaluate the development of this function: 20 children, 20 university students, and 20 elderly people (each group comprising 10 men and 10…

The Role of Perspective Taking in How Children Connect Reference Frames When Explaining Astronomical Phenomena

ERIC Educational Resources Information Center

Plummer, Julia D.; Bower, Corinne A.; Liben, Lynn S.

2016-01-01

This study investigates the role of perspective-taking skills in how children explain spatially complex astronomical phenomena. Explaining many astronomical phenomena, especially those studied in elementary and middle school, requires shifting between an Earth-based description of the phenomena and a space-based reference frame. We studied 7- to…

A Feminist Post-Structuralist Analysis of an Exemplar South African School History Text

ERIC Educational Resources Information Center

Fardon, Jill; Schoeman, Sonja

2010-01-01

A feminist post-structuralist perspective offers an alternative paradigm for the study of gender bias in History texts. It focuses on multiple perspectives and open interpretation, opens up space for female voices of the past and present, and deconstructs realist historical narrative. Our aim in this article is to discuss feminist…

Paul Pintrich: A Once and Continuing Influence

ERIC Educational Resources Information Center

Maehr, Martin L.

2005-01-01

This article provides an integrative perspective on the articles presented in this special issue. It is also a very personal perspective. In such small space it is impossible to do justice fully to Paul's work or to the reflections on that work. What this final article attempts is a statement that emphasizes the scope and depth of this work as…

A Perspective on Education's Importance for Urban Development

ERIC Educational Resources Information Center

Joshi, Priyadarshani

2017-01-01

The 21st century has been called the "age of the city". The concentration of human activity is what makes cities such an important space of opportunity and challenge. This article views urban development challenges from an education perspective and argues that education must be viewed as an important intermediary for capitalising on the…

Systematic Technology Planning: GSFC Perspective

NASA Technical Reports Server (NTRS)

Steiner, Mark

2004-01-01

This viewgraph presentation describes the experiences of Goddard Space Flight Center (GSFC) in integrating systematic technology investment planning into the process of architecting NASA space missions. The presentation uses the assessment of a lidar mission as a case study, and illustrates integration strategies through flow charts and dynamic systems models.

Resistance to Extreme Stresses in the Tardigrada: Experiments on Earth and in Space and Astrobiological Perspectives

NASA Astrophysics Data System (ADS)

Rebecchi, L.; Altiero, T.; Guidetti, R.; Cesari, M.; Rizzo, A. M.; Bertolani, R.

2010-04-01

The ability of tardigrades to enter cryptobiosis al-lows them to resist to extreme stresses: very low or high temperatures, chemicals, high pressure, ionizing and UV radiations This has lead to propose tardigrades as suitable model in space research.

Hearing on Space Situational Awareness:

NASA Image and Video Library

2018-06-22

Rep. Mike Rogers, R-Alabama, Chairman of the Strategic Forces Subcommittee is seen during the House Subcommittee on Strategic Forces hearing on Space Situational Awareness: Whole of Government Perspectives on Roles and Responsibilities, Friday, June 22, 2018 at the Rayburn House Office Building in Washington. Photo Credit: (NASA/Bill Ingalls)

The consumer quality index anthroposophic healthcare: a construction and validation study.

PubMed

Koster, Evi B; Ong, Rob R S; Heybroek, Rachel; Delnoij, Diana M J; Baars, Erik W

2014-04-02

Accounting for the patients' perspective on quality of care has become increasingly important in the development of Evidence Based Medicine as well as in governmental policies. In the Netherlands the Consumer Quality (CQ) Index has been developed to measure the quality of care from the patients' perspective in different healthcare sectors in a standardized manner. Although the scientific accountability of anthroposophic healthcare as a form of integrative medicine is growing, patient experiences with anthroposophic healthcare have not been measured systematically. In addition, the specific anthroposophic aspects are not measured by means of existing CQ Indexes. To enable accountability of quality of the anthroposophic healthcare from the patients' perspective the aim of this study is the construction and validation of a CQ Index for anthroposophic healthcare. Construction in three phases: Phase 1. Determining anthroposophic quality aspects: literature study and focus groups. Phase 2. Adding new questions and validating the new questionnaire. Research population: random sample from 7910 patients of 22 anthroposophic GPs. survey, mixed mode by means of the Dillman method. Measuring instrument: experience questionnaire: CQ Index General Practice (56 items), added with 27 new anthroposophic items added and an item-importance questionnaire (anthroposophic items only). Factor analysis, scale construction, internal consistency (Chronbach's Alpha), inter-item-correlation, discriminative ability (Intra Class Correlation) and inter-factor-correlations. Phase 3. Modulation and selection of new questions based on results. Criteria of retaining items: general: a limited amount of items, statistical: part of a reliable scale and inter-item-correlation <0,7, and theoretical. Phase 1. 27 anthroposophic items. Phase 2. Two new anthroposophic scales: Scale AntroposophicTreatmentGP: seven items, Alpha=0,832, ICC=4,2 Inter-factor-correlation with existing GP-scales range from r=0,24 (Accessibility) to r=0,56 (TailoredCare). Scale InteractionalStyleGP: five items, Alpha=0,810, ICC=5,8, Inter-factor-correlation with existing GP-scales range from r=0,32 (Accessibility) to r=0,76 (TailoredCare). Inter-factor-correlation between new scales: r=0,50. Phase 3: Adding both scales and four single items. Removing eleven items and reformulating two items. The CQ Index Anthroposophic Healthcare measures patient experiences with anthroposophic GP's validly and reliably. Regarding the inter-factor-correlations anthroposophic quality aspects from the patients' perspective are mostly associated with individually tailored care and patient centeredness.

By the Numbers: Expedition 53

NASA Image and Video Library

2017-12-15

If there’s one thing we at NASA love more than acronyms, it’s numbers—we count pretty much everything. Now that the International Space Station’s Expedition 53 has concluded, we gathered up a few of the pertinent numbers to put this mission in perspective. _______________________________________ FOLLOW THE SPACE STATION! Twitter: https://twitter.com/Space_Station Facebook: https://www.facebook.com/ISS Instagram: https://instagram.com/iss/

Octahedral deformations and cationic displacements in the ferroelectric PbHf(0.8)Ti(0.2)O(3): a neutron powder diffraction study from 10 to 770 K

PubMed

Muller; Baudour; Bedoya; Bouree; Soubeyroux; Roubin

2000-02-01

Neutron powder diffraction data, collected over the temperature range 10-770 K, have been analysed in order to make a detailed characterization of the sequence of phase transitions occurring in the Hf-rich ferroelectric PbHf(0.8)Ti(0.2)O3, titanium hafnium lead oxide. Over the whole temperature range this compound undergoes two phase transitions, which involve cationic displacements and octahedral deformations (tilt and/or distortion) leading to strongly distorted perovskite-type structures. The first transition appears around 415 K between two ferroelectric rhombohedral phases: a low-temperature nonzero-tilt phase F(RL) (space group R3c) and an intermediate zero-tilt phase FRH (space group R3m). The second one, detected around 520 K, is associated with a ferroelectric to-paraelectric transition between the FRH phase and the Pc cubic phase (space group Pm3m). From high-resolution neutron powder diffraction data (diffractometer 3T2-LLB, Saclay, France, lambda = 1.2251 A), the crystallographic structure of the three successive phases has been accurately determined at the following temperatures: T = 10 K (FRL): space group R3c, Z = 6, a(hex) = 5.7827 (1), c(hex) = 14.2702 (4) A, V(hex) = 413.26 (2) A3; T = 150 K (F(RL)): space group R3c, Z = 6, a(hex) = 5.7871 (1), C(hex) = 14.2735 (4) A, V(hex) = 413.98 (3) A3; T = 290 K (FRL): space group R3c, Z = 6, a(hex) = 5.7943 (1), C(hex) = 14.2742 (5) A, V(hex) = 415.04 (3) A3; T = 440 K (F(RH)): space group R3c, Z = 6, a(hex) = 5.8025 (1), c(hex) = 14.2648 (4) A, V(hex) = 415.94 (3) A3; T = 520 K (Pc): space group Pm3m, Z = 1, a(cub) = 4.1072 (2) A, V(cub) = 69.29 (1) A3. In addition, a neutron powder thermodiffractometry experiment, performed between 290 and 770 K (diffractometer D1B-ILL, Grenoble, France, lambda = 2.533 A), has been used to study in situ the temperature-induced phase transitions. From sequential Rietveld refinements, the temperature dependence of the cation displacements and the rotation and/or distortion of oxygen octahedra was derived.

Neutral line chaos and phase space structure

NASA Technical Reports Server (NTRS)

Burkhart, Grant R.; Speiser, Theodore W.; Martin, Richard F., Jr.; Dusenbery, Paul B.

1991-01-01

Phase space structure and chaos near a neutral line are studied with numerical surface-of-section (SOS) techniques and analytic methods. Results are presented for a linear neutral line model with zero crosstail electric field. It was found that particle motion can be divided into three regimes dependening on the value of the conserved canonical momentum, Py, and the conserved Hamiltonian, h. The phase space structure, using Poincare SOS plots, is highly sensitive to bn = Bn/B0 variations, but not to h variations. It is verified that the slow motion preserves the action, Jz, as evaluated by Sonnerup (1971), when the period of the fast motion is smaller than the time scale of the slow motion. Results show that the phase space structure and particle chaos depend sensitively upon Py and bn, but are independent of h.

Quantum mechanics on phase space and the Coulomb potential

NASA Astrophysics Data System (ADS)

Campos, P.; Martins, M. G. R.; Vianna, J. D. M.

2017-04-01

Symplectic quantum mechanics (SMQ) makes possible to derive the Wigner function without the use of the Liouville-von Neumann equation. In this formulation of the quantum theory the Galilei Lie algebra is constructed using the Weyl (or star) product with Q ˆ = q ⋆ = q +iħ/2∂p , P ˆ = p ⋆ = p -iħ/2∂q, and the Schrödinger equation is rewritten in phase space; in consequence physical applications involving the Coulomb potential present some specific difficulties. Within this context, in order to treat the Schrödinger equation in phase space, a procedure based on the Levi-Civita (or Bohlin) transformation is presented and applied to two-dimensional (2D) hydrogen atom. Amplitudes of probability in phase space and the correspondent Wigner quasi-distribution functions are derived and discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosales-Zarate, Laura E. C.; Drummond, P. D.

We calculate the quantum Renyi entropy in a phase-space representation for either fermions or bosons. This can also be used to calculate purity and fidelity, or the entanglement between two systems. We show that it is possible to calculate the entropy from sampled phase-space distributions in normally ordered representations, although this is not possible for all quantum states. We give an example of the use of this method in an exactly soluble thermal case. The quantum entropy cannot be calculated at all using sampling methods in classical symmetric (Wigner) or antinormally ordered (Husimi) phase spaces, due to inner-product divergences. Themore » preferred method is to use generalized Gaussian phase-space methods, which utilize a distribution over stochastic Green's functions. We illustrate this approach by calculating the reduced entropy and entanglement of bosonic or fermionic modes coupled to a time-evolving, non-Markovian reservoir.« less

Historical Perspectives in the Care of Patients with Enterocutaneous Fistula

DTIC Science & Technology

2010-09-01

correct hypercatabolism and cachexia that are frequently present. Phase 2, or the investigational phase, involves imaging such as a fistulo- gram and...fluid losses, electrolytes, or nutrients, although they highlight how far we have come. The adverse results of malnutrition to include cachexia

ColDICE: A parallel Vlasov–Poisson solver using moving adaptive simplicial tessellation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sousbie, Thierry, E-mail: tsousbie@gmail.com; Department of Physics, The University of Tokyo, Tokyo 113-0033; Research Center for the Early Universe, School of Science, The University of Tokyo, Tokyo 113-0033

2016-09-15

Resolving numerically Vlasov–Poisson equations for initially cold systems can be reduced to following the evolution of a three-dimensional sheet evolving in six-dimensional phase-space. We describe a public parallel numerical algorithm consisting in representing the phase-space sheet with a conforming, self-adaptive simplicial tessellation of which the vertices follow the Lagrangian equations of motion. The algorithm is implemented both in six- and four-dimensional phase-space. Refinement of the tessellation mesh is performed using the bisection method and a local representation of the phase-space sheet at second order relying on additional tracers created when needed at runtime. In order to preserve in the bestmore » way the Hamiltonian nature of the system, refinement is anisotropic and constrained by measurements of local Poincaré invariants. Resolution of Poisson equation is performed using the fast Fourier method on a regular rectangular grid, similarly to particle in cells codes. To compute the density projected onto this grid, the intersection of the tessellation and the grid is calculated using the method of Franklin and Kankanhalli [65–67] generalised to linear order. As preliminary tests of the code, we study in four dimensional phase-space the evolution of an initially small patch in a chaotic potential and the cosmological collapse of a fluctuation composed of two sinusoidal waves. We also perform a “warm” dark matter simulation in six-dimensional phase-space that we use to check the parallel scaling of the code.« less

Characterization of Dynamical Phase Transitions in Quantum Jump Trajectories Beyond the Properties of the Stationary State

NASA Astrophysics Data System (ADS)

Lesanovsky, Igor; van Horssen, Merlijn; Guţă, Mădălin; Garrahan, Juan P.

2013-04-01

We describe how to characterize dynamical phase transitions in open quantum systems from a purely dynamical perspective, namely, through the statistical behavior of quantum jump trajectories. This approach goes beyond considering only properties of the steady state. While in small quantum systems dynamical transitions can only occur trivially at limiting values of the controlling parameters, in many-body systems they arise as collective phenomena and within this perspective they are reminiscent of thermodynamic phase transitions. We illustrate this in open models of increasing complexity: a three-level system, the micromaser, and a dissipative version of the quantum Ising model. In these examples dynamical transitions are accompanied by clear changes in static behavior. This is however not always the case, and, in general, dynamical phases need to be uncovered by observables which are strictly dynamical, e.g., dynamical counting fields. We demonstrate this via the example of a class of models of dissipative quantum glasses, whose dynamics can vary widely despite having identical (and trivial) stationary states.

Characterization of dynamical phase transitions in quantum jump trajectories beyond the properties of the stationary state.

PubMed

Lesanovsky, Igor; van Horssen, Merlijn; Guţă, Mădălin; Garrahan, Juan P

2013-04-12

We describe how to characterize dynamical phase transitions in open quantum systems from a purely dynamical perspective, namely, through the statistical behavior of quantum jump trajectories. This approach goes beyond considering only properties of the steady state. While in small quantum systems dynamical transitions can only occur trivially at limiting values of the controlling parameters, in many-body systems they arise as collective phenomena and within this perspective they are reminiscent of thermodynamic phase transitions. We illustrate this in open models of increasing complexity: a three-level system, the micromaser, and a dissipative version of the quantum Ising model. In these examples dynamical transitions are accompanied by clear changes in static behavior. This is however not always the case, and, in general, dynamical phases need to be uncovered by observables which are strictly dynamical, e.g., dynamical counting fields. We demonstrate this via the example of a class of models of dissipative quantum glasses, whose dynamics can vary widely despite having identical (and trivial) stationary states.

Perspectives and Open Problems in the Early Phases of Left-Right Patterning

PubMed Central

Vandenberg, Laura N.; Levin, Michael

2009-01-01

Summary Embryonic left-right (LR) patterning is a fascinating aspect of embryogenesis. The field currently faces important questions about the origin of LR asymmetry, the mechanisms by which consistent asymmetry is imposed on the scale of the whole embryo, and the degree of conservation of early phases of LR patterning among model systems. Recent progress on planar cell polarity and cellular asymmetry in a variety of tissues and species provides a new perspective on the early phases of LR patterning. Despite the huge diversity in body-plans over which consistent LR asymmetry is imposed, and the apparent divergence in molecular pathways that underlie laterality, the data reveal conservation of physiological modules among phyla and a basic scheme of cellular chirality amplified by a planar cell polarity-like pathway over large cell fields. PMID:19084609

Experimental demonstration of electron longitudinal-phase-space linearization by shaping the photoinjector laser pulse.

PubMed

Penco, G; Danailov, M; Demidovich, A; Allaria, E; De Ninno, G; Di Mitri, S; Fawley, W M; Ferrari, E; Giannessi, L; Trovó, M

2014-01-31

Control of the electron-beam longitudinal-phase-space distribution is of crucial importance in a number of accelerator applications, such as linac-driven free-electron lasers, colliders and energy recovery linacs. Some longitudinal-phase-space features produced by nonlinear electron beam self- fields, such as a quadratic energy chirp introduced by geometric longitudinal wakefields in radio-frequency (rf) accelerator structures, cannot be compensated by ordinary tuning of the linac rf phases nor corrected by a single high harmonic accelerating cavity. In this Letter we report an experimental demonstration of the removal of the quadratic energy chirp by properly shaping the electron beam current at the photoinjector. Specifically, a longitudinal ramp in the current distribution at the cathode linearizes the longitudinal wakefields in the downstream linac, resulting in a flat electron current and energy distribution. We present longitudinal-phase-space measurements in this novel configuration compared to those typically obtained without longitudinal current shaping at the FERMI linac.

LCA in space - current status and future development

NASA Astrophysics Data System (ADS)

Ko, Nathanael; Betten, Thomas; Schestak, Isabel; Gantner, Johannes

2018-06-01

This paper represents the first stage of extending the scope of LCA to space and is intended as a discussion starter. Based on the assumption, that the future and outlast of humanity lies within the exploration and colonisation of space, the LCA methodology as of today, is discussed with regards to its capabilities to cover the impact of human activities in space. Based on this assessment, ideas whether and how LCA can be extended are outlined. Initially, an understanding of additional environmental impacts which occur in space compared to Earth is built up by the means of literature research. The state of the art of space regulations and availability of LCAs in space and for astronautics is clarified as well. Further literature research was conducted on the LCA subtopic of regionalization. Based on this and assumptions regarding future space travel, the suitability of LCA as an assessment method is validated. Afterwards, different potential development phases of LCA towards its applicability in space are defined. For activities in space, the regarded environmental impacts have to be expanded (e.g. space debris, extra-terrestrial life toxicity, etc.). Space regulations, if in place, cover only impacts of space activities on Earth so far. LCAs for space activities are not widespread yet. One reason for this is that the state of the art LCA methodology has not been expanded and existing regionalisation approaches are not easily transferable to space. Critical issues are faced in all phases of an LCA and include widening of boundaries, definition of space regions, finding suitable reference units and ethical problems. As a result, four LCA development phases are suggested: Earth-bound, solar system-bound, transition phase and intergalactic. Each phase involves different activities and goals, which result in different system boundaries and impact categories and widen the scope of LCA subsequently. It is a long way for humanity to populate space and so, it is for enabling LCA to assess these activities. The methodology of LCA is flexible and capable to make this adaptation. This paper can be seen as a starting point of a discussion opening up many questions. Some of these questions can only be answered in the future with more certainty about the development of space colonialization.

Earth-to-Orbit Rocket Propulsion

NASA Technical Reports Server (NTRS)

Beaurain, Andre; Souchier, Alain; Moravie, Michel; Sackheim, Robert L.; Cikanek, Harry A., III

2003-01-01

The Earth-to-orbit (ETO) phase of access to space is and always will be the first and most critical phase of all space missions. This first phase of all space missions has unique characteristics that have driven space launcher propulsion requirements for more than half a century. For example, the need to overcome the force of the Earth s gravity in combination with high levels of atmospheric drag to achieve the initial orbital velocity; i.e., Earth parking orbit or =9 km/s, will always require high thrust- to-weight (TN) propulsion systems. These are necessary with a T/W ratio greater than one during the ascent phase. The only type of propulsion system that can achieve these high T/W ratios are those that convert thermal energy to kinetic energy. There are only two basic sources of onboard thermal energy: chemical combustion-based systems or nuclear thermal-based systems (fission, fusion, or antimatter). The likelihood of advanced open-cycle, nuclear thermal propulsion being developed for flight readiness or becoming environmentally acceptable during the next century is extremely low. This realization establishes that chemical propulsion for ET0 launchers will be the technology of choice for at least the next century, just as it has been for the last half century of rocket flight into space. The world s space transportation propulsion requirements have evolved through several phases over the history of the space program, as has been necessitated by missions and systems development, technological capabilities available, and the growth and evolution of the utilization of space for economic, security, and science benefit. Current projections for the continuing evolution of requirements and concepts may show how future space transportation system needs could be addressed. The evolution and projections will be described in detail in this manuscript.

Resonance controlled transport in phase space

NASA Astrophysics Data System (ADS)

Leoncini, Xavier; Vasiliev, Alexei; Artemyev, Anton

2018-02-01

We consider the mechanism of controlling particle transport in phase space by means of resonances in an adiabatic setting. Using a model problem describing nonlinear wave-particle interaction, we show that captures into resonances can be used to control transport in momentum space as well as in physical space. We design the model system to provide creation of a narrow peak in the distribution function, thus producing effective cooling of a sub-ensemble of the particles.

Space-charge-sustained microbunch structure in the Los Alamos Proton Storage Ring

NASA Astrophysics Data System (ADS)

Cousineau, S.; Danilov, V.; Holmes, J.; Macek, R.

2004-09-01

We present experimental data from the Los Alamos Proton Storage Ring (PSR) showing long-lived linac microbunch structure during beam storage with no rf bunching. Analysis of the experimental data and particle-in-cell simulations of the experiments indicate that space charge, coupled with energy spread effects, is responsible for the sustained microbunch structure. The simulated longitudinal phase space of the beam reveals a well-defined separatrix in the phase space between linac microbunches, with particles executing unbounded motion outside of the separatrix. We show that the longitudinal phase space of the beam was near steady state during the PSR experiments, such that the separatrix persisted for long periods of time. Our simulations indicate that the steady state is very sensitive to the experimental conditions. Finally, we solve the steady-state problem in an analytic, self-consistent fashion for a set of periodic longitudinal space-charge potentials.

Rocket experiment METS Microwave Energy Transmission in Space

NASA Astrophysics Data System (ADS)

Kaya, N.; Matsumoto, H.; Akiba, R.

A METS (Microwave Energy Transmission in Space) rocket experiment is being planned by the SPS (Solar Power Satellite) Working Group at the Institute of Space and Astronautical Science (ISAS) in Japan for the forthcoming International Space Year (ISY), 1992. The METS experiment is an advanced version of our MINIX rocket experiment. This paper describes the conceptual design for the METS rocket experiment. Aims are to verify the feasibility of a newly developed microwave energy transmission system designed for use in space and to study nonlinear effects of the microwave energy beam on space plasma. A high power microwave (936 W) will be transmitted by a new phase-array antenna from a mother rocket to a separate target (daughter rocket) through the Earth's ionospheric plasma. The active phased-array system has the capability of being able to focus the microwave energy at any spatial point by individually controlling the digital phase shifters.

Rocket experiment METS - Microwave Energy Transmission in Space

NASA Astrophysics Data System (ADS)

Kaya, N.; Matsumoto, H.; Akiba, R.

A Microwave Energy Transmission in Space (METS) rocket experiment is being planned by the Solar Power Satellite Working Group at the Institute of Space and Astronautical Science in Japan for the forthcoming International Space Year, 1992. The METS experiment is an advanced version of the previous MINIX rocket experiment (Matsumoto et al., 1990). This paper describes a conceptual design of the METS rocket experiment. It aims at verifying a newly developed microwave energy transmission system for space use and to study nonlinear effects of the microwave energy beam in the space plasma environment. A high power microwave of 936 W will be transmitted by the new phased-array antenna from a mother rocket to a separated target (daughter rocket) through the ionospheric plasma. The active phased-array system has a capability of focusing the microwave energy around any spatial point by controlling the digital phase shifters individually.

Dual Phase-space Cascades in 3D Hybrid-Vlasov–Maxwell Turbulence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cerri, S. S.; Kunz, M. W.; Califano, F.

To explain energy dissipation via turbulence in collisionless, magnetized plasmas, the existence of a dual real- and velocity-space cascade of ion-entropy fluctuations below the ion gyroradius has been proposed. Such a dual cascade, predicted by the gyrokinetic theory, has previously been observed in gyrokinetic simulations of two-dimensional, electrostatic turbulence. For the first time we show evidence for a dual phase-space cascade of ion-entropy fluctuations in a three-dimensional simulation of hybrid-kinetic, electromagnetic turbulence. Some of the scalings observed in the energy spectra are consistent with a generalized theory for the cascade that accounts for the spectral anisotropy of critically balanced, intermittent,more » sub-ion-Larmor-scale fluctuations. Also, the observed velocity-space cascade is anisotropic with respect to the magnetic-field direction, with linear phase mixing along magnetic-field lines proceeding mainly at spatial scales above the ion gyroradius and nonlinear phase mixing across magnetic-field lines proceeding at perpendicular scales below the ion gyroradius. Such phase-space anisotropy could be sought in heliospheric and magnetospheric data of solar-wind turbulence and has far-reaching implications for the dissipation of turbulence in weakly collisional astrophysical plasmas.« less

Quantum-field-theoretical approach to phase-space techniques: Generalizing the positive-P representation

NASA Astrophysics Data System (ADS)

Plimak, L. I.; Fleischhauer, M.; Olsen, M. K.; Collett, M. J.

2003-01-01

We present an introduction to phase-space techniques (PST) based on a quantum-field-theoretical (QFT) approach. In addition to bridging the gap between PST and QFT, our approach results in a number of generalizations of the PST. First, for problems where the usual PST do not result in a genuine Fokker-Planck equation (even after phase-space doubling) and hence fail to produce a stochastic differential equation (SDE), we show how the system in question may be approximated via stochastic difference equations (SΔE). Second, we show that introducing sources into the SDE’s (or SΔE’s) generalizes them to a full quantum nonlinear stochastic response problem (thus generalizing Kubo’s linear reaction theory to a quantum nonlinear stochastic response theory). Third, we establish general relations linking quantum response properties of the system in question to averages of operator products ordered in a way different from time normal. This extends PST to a much wider assemblage of operator products than are usually considered in phase-space approaches. In all cases, our approach yields a very simple and straightforward way of deriving stochastic equations in phase space.

Dual Phase-space Cascades in 3D Hybrid-Vlasov–Maxwell Turbulence

DOE PAGES

Cerri, S. S.; Kunz, M. W.; Califano, F.

2018-03-23

To explain energy dissipation via turbulence in collisionless, magnetized plasmas, the existence of a dual real- and velocity-space cascade of ion-entropy fluctuations below the ion gyroradius has been proposed. Such a dual cascade, predicted by the gyrokinetic theory, has previously been observed in gyrokinetic simulations of two-dimensional, electrostatic turbulence. For the first time we show evidence for a dual phase-space cascade of ion-entropy fluctuations in a three-dimensional simulation of hybrid-kinetic, electromagnetic turbulence. Some of the scalings observed in the energy spectra are consistent with a generalized theory for the cascade that accounts for the spectral anisotropy of critically balanced, intermittent,more » sub-ion-Larmor-scale fluctuations. Also, the observed velocity-space cascade is anisotropic with respect to the magnetic-field direction, with linear phase mixing along magnetic-field lines proceeding mainly at spatial scales above the ion gyroradius and nonlinear phase mixing across magnetic-field lines proceeding at perpendicular scales below the ion gyroradius. Such phase-space anisotropy could be sought in heliospheric and magnetospheric data of solar-wind turbulence and has far-reaching implications for the dissipation of turbulence in weakly collisional astrophysical plasmas.« less

A technique for generating phase-space-based Monte Carlo beamlets in radiotherapy applications.

PubMed

Bush, K; Popescu, I A; Zavgorodni, S

2008-09-21

As radiotherapy treatment planning moves toward Monte Carlo (MC) based dose calculation methods, the MC beamlet is becoming an increasingly common optimization entity. At present, methods used to produce MC beamlets have utilized a particle source model (PSM) approach. In this work we outline the implementation of a phase-space-based approach to MC beamlet generation that is expected to provide greater accuracy in beamlet dose distributions. In this approach a standard BEAMnrc phase space is sorted and divided into beamlets with particles labeled using the inheritable particle history variable. This is achieved with the use of an efficient sorting algorithm, capable of sorting a phase space of any size into the required number of beamlets in only two passes. Sorting a phase space of five million particles can be achieved in less than 8 s on a single-core 2.2 GHz CPU. The beamlets can then be transported separately into a patient CT dataset, producing separate dose distributions (doselets). Methods for doselet normalization and conversion of dose to absolute units of Gy for use in intensity modulated radiation therapy (IMRT) plan optimization are also described.

Dual Phase-space Cascades in 3D Hybrid-Vlasov–Maxwell Turbulence

NASA Astrophysics Data System (ADS)

Cerri, S. S.; Kunz, M. W.; Califano, F.

2018-03-01

To explain energy dissipation via turbulence in collisionless, magnetized plasmas, the existence of a dual real- and velocity-space cascade of ion-entropy fluctuations below the ion gyroradius has been proposed. Such a dual cascade, predicted by the gyrokinetic theory, has previously been observed in gyrokinetic simulations of two-dimensional, electrostatic turbulence. For the first time, we show evidence for a dual phase-space cascade of ion-entropy fluctuations in a three-dimensional simulation of hybrid-kinetic, electromagnetic turbulence. Some of the scalings observed in the energy spectra are consistent with a generalized theory for the cascade that accounts for the spectral anisotropy of critically balanced, intermittent, sub-ion-Larmor-scale fluctuations. The observed velocity-space cascade is also anisotropic with respect to the magnetic-field direction, with linear phase mixing along magnetic-field lines proceeding mainly at spatial scales above the ion gyroradius and nonlinear phase mixing across magnetic-field lines proceeding at perpendicular scales below the ion gyroradius. Such phase-space anisotropy could be sought in heliospheric and magnetospheric data of solar-wind turbulence and has far-reaching implications for the dissipation of turbulence in weakly collisional astrophysical plasmas.

Space transfer concepts and analysis for exploration missions

NASA Technical Reports Server (NTRS)

1991-01-01

Covered here is the second phase of a broad scoped and systematic study of space transfer concepts for human lunar and Mars missions. The study addressed issues that were raised during Phase 1, developed generic Mars missions profile analysis data, and conducted preliminary analysis of the Mars in-space transportation requirements and implementation from the Stafford Committee Synthesis Report.

Theoretical calculations of high-pressure phases of NiF2: An ab initio constant-pressure study

NASA Astrophysics Data System (ADS)

Kürkçü, Cihan; Merdan, Ziya; Öztürk, Hülya

2016-12-01

We have studied the structural properties of the antiferromagnetic NiF2 tetragonal structure with P42/ mnm symmetry using density functional theory (DFT) under rapid hydrostatic pressure up to 400 GPa. For the exchange correlation energy we used the local density approximation (LDA) of Ceperley and Alder (CA). Two phase transformations are successfully observed through the simulations. The structures of XF2-type compounds crystallize in rutile-type structure. NiF2 undergoes phase transformations from the tetragonal rutile-type structure with space group P42/ mnm to orthorhombic CaCl2-type structure with space group Pnnm and from this orthorhombic phase to monoclinic structure with space group C2/ m at 152 GPa and 360 GPa, respectively. These phase changes are also studied by total energy and enthalpy calculations. According to these calculations, we perdict these phase transformations at about 1.85 and 30 GPa.

Phase change references for in-flight recalibration of orbital thermometry

NASA Astrophysics Data System (ADS)

Topham, T. S.; Latvakoski, H.; Watson, M.

2013-09-01

Several critical questions need to be answered to determine the potential utility of phase change materials as long-term orbital references: How accurate and repeatable will phase change reference implementations be after incorporating necessary design trade-offs to accommodate launch and the space environment? How can the temperature of phase transitions be transferred to something useful for calibration such as a black body. How, if at all, will the microgravity environment affect the phase transitions? To help answer some of these questions, three experiments will be conducted on the International Space Station (ISS). The experiments will test melts and freezes of three different phase change materials in various containment apparatus. This paper addresses the current status of the ISS experiments, as well as results from ground testing of several concepts for space application of PCM recalibration systems in the CORSAIR (Calibration Observations of Radiance Spectra in the far Infrared) black body.

Constellation Program Thermal and Environmental Control and Life Support System Status: 2009 - 2010

NASA Technical Reports Server (NTRS)

Williams, David E.; Carrasquillo, Robyn L.; Bagdigian, Robert M.

2009-01-01

The Constellation Program (CxP) consists of spacecrafts, launch vehicles, and support systems to execute the Exploration Architecture. The Program is currently divided into three distinct phases. The first phase is to develop a vehicle to provide limited cargo resupply capability and allow crew member rotation to the International Space Station (ISS). The second phase is to support the return of humans to the moon. The final phase is currently envisioned to allow the delivery of humans and cargo to Mars for an extended time. To implement this phased approach the CxP is currently working on the first vehicle and support systems to replace the Space Shuttle and allow continued access to space. This paper provides a summary of the CxP Thermal and Environmental Control and Life Support (ECLS) work that that has occurred across the different parts of the Program in support of these three phases over the past year.

How to Assess Professional Competencies in Education for Sustainability?: An Approach from a Perspective of Complexity

ERIC Educational Resources Information Center

Garcia, Maria Rosa; Junyent, Mercè; Fonolleda, Marta

2017-01-01

Purpose: This study aims to contribute to the professional competency approach in Education for Sustainability (ES) from the perspective of complexity and to the assessment of these competencies. Design/methodology/approach: A qualitative research process was used, which consisted of two main phases--a documentary analysis of the internationally…

Understanding Personal Learning Environment Perspectives of Thai International Tourism and Hospitality Higher Education Students

ERIC Educational Resources Information Center

Tanyong, Siriwan; Sharafuddin, Mohamed Ali

2016-01-01

This paper is part of a periodic research conducted in developing a personal learning environment for Thailand's higher education students with English as medium of instruction. The objective of the first phase in this research was to understand the personal learning environment perspectives of Thai International tourism and hospitality higher…

Exploring Links between Empowerment and Community-Based Arts and Cultural Practices: Perspectives from Barcelona Practitioners

ERIC Educational Resources Information Center

Carrasco, Ruben David Fernández; Monferrer, Moisés Carmona; Tarditi, Andrés Di Masso

2016-01-01

In this paper, we reflect on the development of community-based arts and cultural (CBAC) practices to promote psychosocial, group/organisational and community changes from the perspective of empowerment. We draw on findings from an initial exploratory phase of an ongoing action-research project in Spain about creative tools that empower artists…

Using the Space Glove to Teach Spatial Thinking

NASA Technical Reports Server (NTRS)

Lord, Peter

2008-01-01

The challenge of extending students' skills in spatial thinking to astronomical scales was the central focus of our K-8 curriculum development. When the project's lead teacher requested a curriculum that cumulatively built on each prior year's learning in a spiral fashion, I knew exactly what the school was asking for. Second and third graders began by noticing the cyclical patters that the sun, moon, and stars make in the sky. Fourth graders explored the phases of the moon by taking turns modeling and sketching them in their classroom and then comparing them to the real sky. Sixth !graders used real telescopes to observe a moving model of our solar system and walked a scale model of the planets' orbits. The curriculum is designed to expand students' capacity to visualize space in a hierarchical fashion that asks them to imagine themselves from a broader number of spatial perspectives through hands-on activities. The "situational awareness" Peter's story describes is a hallmark of high-performance engineering and innovation. Keeping in mind the potential outcomes of multiple paths of pursuit from multiple perspectives while keeping track of their relative merits and performance requirements is a demanding spatial task. What made it possible for Peter to transform the failure of his first glove into triumph was the mental space in which that failure provided exactly the information needed for a new breakthrough. In at least two cases, Peter could immediately "see" the full implications of what his hands were telling him. He tells the story of how putting his hands in a Phase VI astronaut glove instantly transformed his understanding of the glove challenge. Six months into his development, the failure of circumferentially wrapped cords to produce a sufficiently flexible glove again forced him to abandon his assumptions. His situational awareness was so clear and compelling it became a gut-level response. Peter's finely developed spatial skills enabled him to almost instinctively focus his full energy on a carefully constructed set of experiments. The finger's ability to sense pressure, force, and work gave him the immediate feedback required to solve this one central problem. Once properly understood, his failure quickly led to the magical "Aha!" moment of discovery; the rest is history. Just as children need opportunities to develop hands-on understanding, engineers need to explore new possibilities through incremental hands-on failure. High-performance innovation is all about learning to make maximum use of thinking spatially to direct this process. Peter Homer's glove also reminds us that efficient engineering decisions need to be made as close to the hardware as possible. Whether we're doing hands-on education or hands-on engineering, it is when we trust in our ability to "feel our way" through failure that we reach our highest potential.

Reliability and the design process at Honeywell Avionics Division

NASA Technical Reports Server (NTRS)

Bezat, A.

1981-01-01

The division's philosophy for designed-in reliability and a comparison of reliability programs for space, manned military aircraft, and commercial aircraft, are presented. Topics include: the reliability interface with design and production; the concept phase through final proposal; the design, development, test and evaluation phase; the production phase; and the commonality among space, military, and commercial avionics.

A phase one AR/C system design

NASA Technical Reports Server (NTRS)

Kachmar, Peter M.; Polutchko, Robert J.; Matusky, Martin; Chu, William; Jackson, William; Montez, Moises

1991-01-01

The Phase One AR&C System Design integrates an evolutionary design based on the legacy of previous mission successes, flight tested components from manned Rendezvous and Proximity Operations (RPO) space programs, and additional AR&C components validated using proven methods. The Phase One system has a modular, open architecture with the standardized interfaces proposed for Space Station Freedom system architecture.

A cognitive computational model inspired by the immune system response.

PubMed

Abdo Abd Al-Hady, Mohamed; Badr, Amr Ahmed; Mostafa, Mostafa Abd Al-Azim

2014-01-01

The immune system has a cognitive ability to differentiate between healthy and unhealthy cells. The immune system response (ISR) is stimulated by a disorder in the temporary fuzzy state that is oscillating between the healthy and unhealthy states. However, modeling the immune system is an enormous challenge; the paper introduces an extensive summary of how the immune system response functions, as an overview of a complex topic, to present the immune system as a cognitive intelligent agent. The homogeneity and perfection of the natural immune system have been always standing out as the sought-after model we attempted to imitate while building our proposed model of cognitive architecture. The paper divides the ISR into four logical phases: setting a computational architectural diagram for each phase, proceeding from functional perspectives (input, process, and output), and their consequences. The proposed architecture components are defined by matching biological operations with computational functions and hence with the framework of the paper. On the other hand, the architecture focuses on the interoperability of main theoretical immunological perspectives (classic, cognitive, and danger theory), as related to computer science terminologies. The paper presents a descriptive model of immune system, to figure out the nature of response, deemed to be intrinsic for building a hybrid computational model based on a cognitive intelligent agent perspective and inspired by the natural biology. To that end, this paper highlights the ISR phases as applied to a case study on hepatitis C virus, meanwhile illustrating our proposed architecture perspective.

A Cognitive Computational Model Inspired by the Immune System Response

PubMed Central

Abdo Abd Al-Hady, Mohamed; Badr, Amr Ahmed; Mostafa, Mostafa Abd Al-Azim

2014-01-01

The immune system has a cognitive ability to differentiate between healthy and unhealthy cells. The immune system response (ISR) is stimulated by a disorder in the temporary fuzzy state that is oscillating between the healthy and unhealthy states. However, modeling the immune system is an enormous challenge; the paper introduces an extensive summary of how the immune system response functions, as an overview of a complex topic, to present the immune system as a cognitive intelligent agent. The homogeneity and perfection of the natural immune system have been always standing out as the sought-after model we attempted to imitate while building our proposed model of cognitive architecture. The paper divides the ISR into four logical phases: setting a computational architectural diagram for each phase, proceeding from functional perspectives (input, process, and output), and their consequences. The proposed architecture components are defined by matching biological operations with computational functions and hence with the framework of the paper. On the other hand, the architecture focuses on the interoperability of main theoretical immunological perspectives (classic, cognitive, and danger theory), as related to computer science terminologies. The paper presents a descriptive model of immune system, to figure out the nature of response, deemed to be intrinsic for building a hybrid computational model based on a cognitive intelligent agent perspective and inspired by the natural biology. To that end, this paper highlights the ISR phases as applied to a case study on hepatitis C virus, meanwhile illustrating our proposed architecture perspective. PMID:25003131

The War on Democratic Public Space: A Perspective from the United States

ERIC Educational Resources Information Center

Hill, Robert J.

2006-01-01

There is a crisis in democratic public space in the USA. This essay explores key areas that are either causes or effects of the present predicament: post-9-11 fear, neoliberalisation/globalisation, migrating populations, and the growing power of right-wing fundamentalism, among others. (Contains 6 notes.)

La politique scientifique comme mise en espace-temps de la recherche= Science Policy as Placed in the Space-Time Relationship of Research.

ERIC Educational Resources Information Center

Turmel, Andre

1986-01-01

The language used by scientists to discuss their work and the social logic underlying scientific research is examined, and viewed from the perspective and as an extension of the space-time continuum that scientists study. (Author/MSE)

Multimodal Self-Authoring across Bi/Multilingual Educator and Student Learning Spaces

ERIC Educational Resources Information Center

Valdez, Verónica E.; Omerbašic, Delila

2015-01-01

Drawing on sociocultural perspectives, this article illustrates the potential for extending figured worlds through cultural artifacts. Using thematic and multimodal analysis, the authors first compare how spaces of authoring were produced in two professional development settings: Proyecto Bilingüe and Critical Education Studies. Following one…

Spatial Theorizing in Comparative and International Education Research

ERIC Educational Resources Information Center

Larsen, Marianne A.; Beech, Jason

2014-01-01

The authors argue for a critical spatial perspective in comparative and international education. We briefly summarize how time and space have been conceptualized within our field. We then review mainstream social science literature that reflects a metanarrative, which we critique for contributing to false dichotomies between space and place and…

Constructing Relational Space in Early Childhood Education

ERIC Educational Resources Information Center

Vuorisalo, Mari; Rutanen, Niina; Raittila, Raija

2015-01-01

This paper examines early childhood education (ECE) by applying and developing relational-spatial perspectives on everyday life in educational institutions for young children. The aim is to investigate the dynamic process of construction of space and to illustrate with selected empirical episodes how this process occurs in ECE. Drawing on authors…

Creating Spaces for Children's Agency: "I Wonder…" Formulations in Teacher-Child Interactions

ERIC Educational Resources Information Center

Houen, Sandy; Danby, Susan; Farrell, Ann; Thorpe, Karen

2016-01-01

Affording children's agency is an important pedagogical underpinning of a high-quality early childhood program. Yet little is known about how teachers' interactions create spaces for children's agency. From the perspectives of ethnomethodology and conversation analysis, this paper investigates how teachers and children navigate agency through…

Designing Computer-Based Assessments: Multidisciplinary Findings and Student Perspectives

ERIC Educational Resources Information Center

Dembitzer, Leah; Zelikovitz, Sarah; Kettler, Ryan J.

2017-01-01

A partnership was created between psychologists and computer programmers to develop a computer-based assessment program. Psychometric concerns of accessibility, reliability, and validity were juxtaposed with core development concepts of usability and user-centric design. Phases of development were iterative, with evaluation phases alternating with…

Interaction geometry: an ecological perspective.

Treesearch

Rolfe A. Leary

1976-01-01

A new mathematical coordinate system results from a unique combination of two frameworks long used by ecologists: the phase plane and coaction cross-tabulation. The resulting construct combines the classifying power of the cross-tabulation and discriminating power of the phase plane. It may be used for analysis and synthesis.

Dynamics of the Trapped Electron Phase Space Density in Relation to the Wave Activity in the Inner Magnetosphere

NASA Astrophysics Data System (ADS)

Vassiliadis, D.; Green, J.

2008-05-01

The phase space density fe of the radiation belt electron population is reconstructed based on measurements made by POLAR/HIST. The density peaks in invariant space (mu, K, L*) are shown to be responding to changes in the solar wind velocity and density, and the interplanetary magnetic field. We have associated specific types of storms with the appearance of peaks thereby producing a climatology of fe. We will report on comparing the phase space density changes during these storms to the ULF wave power in the inner magnetosphere remote- sensed by the IMAGE magnetometer array and related properties of the wave environment.

Pre-Service Perspectives on E-Teaching: Assessing E-Teaching Using the EPEC Hierarchy of Conditions for E-Learning/Teaching Competence

ERIC Educational Resources Information Center

Sisco, Ashley; Woodcock, Stuart; Eady, Michelle

2015-01-01

This article reports on the findings of phase two of a larger study, which examines pre-service teacher experiences engaging with a synchronous (live-time) platform as a part of their training. While phase one focused on pre-service experiences "e-learning" with this synchronous platform (Woodcock, Sisco, & Eady, 2015), phase two…

Earth Observation

NASA Image and Video Library

2014-09-04

ISS040-E-125332 (4 Sept. 2014) --- Palm Jumeirah, protruding off the Persian Gulf Coast of Dubai in the United Arab Emirates, is featured in this 800mm photograph, taken by one of the Expedition 40 crew members aboard the International Space Station. The municipality of Dubai is the largest city of the Persian Gulf emirate of the same name, and has built a global reputation for large-scale developments and architectural works. Among the most visible of these developments ? particularly from the perspective of crew members onboard the space station ? are three man-made archipelagos. The two Palm Islands (Palm Jumeirah and Palm Jebel Ali, which is not in this frame) appear as stylized palm trees when viewed from above. The World Islands evoke a rough map of the world from an air- or space-borne perspective. A very small part of the World Islands is seen in upper left corner.

Megawatt level electric propulsion perspectives

NASA Technical Reports Server (NTRS)

Jahn, Robert G.; Kelly, Arnold J.

1987-01-01

For long range space missions, deliverable payload fraction is an inverse exponential function of the propellant exhaust velocity or specific impulse of the propulsion system. The exhaust velocity of chemical systems are limited by their combustion chemistry and heat transfer to a few km/s. Nuclear rockets may achieve double this range, but are still heat transfer limited and ponderous to develop. Various electric propulsion systems can achieve exhaust velocities in the 10 km/s range, at considerably lower thrust densities, but require an external electrical power source. A general overview is provided of the currently available electric propulsion systems from the perspective of their characteristics as a terminal load for space nuclear systems. A summary of the available electric propulsion options is shown and generally characterized in the power vs. exhaust velocity plot. There are 3 general classes of electric thruster devices: neutral gas heaters, plasma devices, and space charge limited electrostatic or ion thrusters.

Grassmann phase space methods for fermions. II. Field theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dalton, B.J., E-mail: bdalton@swin.edu.au; Jeffers, J.; Barnett, S.M.

In both quantum optics and cold atom physics, the behaviour of bosonic photons and atoms is often treated using phase space methods, where mode annihilation and creation operators are represented by c-number phase space variables, with the density operator equivalent to a distribution function of these variables. The anti-commutation rules for fermion annihilation, creation operators suggests the possibility of using anti-commuting Grassmann variables to represent these operators. However, in spite of the seminal work by Cahill and Glauber and a few applications, the use of Grassmann phase space methods in quantum-atom optics to treat fermionic systems is rather rare, thoughmore » fermion coherent states using Grassmann variables are widely used in particle physics. This paper presents a phase space theory for fermion systems based on distribution functionals, which replace the density operator and involve Grassmann fields representing anti-commuting fermion field annihilation, creation operators. It is an extension of a previous phase space theory paper for fermions (Paper I) based on separate modes, in which the density operator is replaced by a distribution function depending on Grassmann phase space variables which represent the mode annihilation and creation operators. This further development of the theory is important for the situation when large numbers of fermions are involved, resulting in too many modes to treat separately. Here Grassmann fields, distribution functionals, functional Fokker–Planck equations and Ito stochastic field equations are involved. Typical applications to a trapped Fermi gas of interacting spin 1/2 fermionic atoms and to multi-component Fermi gases with non-zero range interactions are presented, showing that the Ito stochastic field equations are local in these cases. For the spin 1/2 case we also show how simple solutions can be obtained both for the untrapped case and for an optical lattice trapping potential.« less

High-order continuum kinetic method for modeling plasma dynamics in phase space

DOE PAGES

Vogman, G. V.; Colella, P.; Shumlak, U.

2014-12-15

Continuum methods offer a high-fidelity means of simulating plasma kinetics. While computationally intensive, these methods are advantageous because they can be cast in conservation-law form, are not susceptible to noise, and can be implemented using high-order numerical methods. Advances in continuum method capabilities for modeling kinetic phenomena in plasmas require the development of validation tools in higher dimensional phase space and an ability to handle non-cartesian geometries. To that end, a new benchmark for validating Vlasov-Poisson simulations in 3D (x,v x,v y) is presented. The benchmark is based on the Dory-Guest-Harris instability and is successfully used to validate a continuummore » finite volume algorithm. To address challenges associated with non-cartesian geometries, unique features of cylindrical phase space coordinates are described. Preliminary results of continuum kinetic simulations in 4D (r,z,v r,v z) phase space are presented.« less

Classical phase space and Hadamard states in the BRST formalism for gauge field theories on curved spacetime

NASA Astrophysics Data System (ADS)

Wrochna, Michał; Zahn, Jochen

We investigate linearized gauge theories on globally hyperbolic spacetimes in the BRST formalism. A consistent definition of the classical phase space and of its Cauchy surface analogue is proposed. We prove that it is isomorphic to the phase space in the ‘subsidiary condition’ approach of Hack and Schenkel in the case of Maxwell, Yang-Mills, and Rarita-Schwinger fields. Defining Hadamard states in the BRST formalism in a standard way, their existence in the Maxwell and Yang-Mills case is concluded from known results in the subsidiary condition (or Gupta-Bleuler) formalism. Within our framework, we also formulate criteria for non-degeneracy of the phase space in terms of BRST cohomology and discuss special cases. These include an example in the Yang-Mills case, where degeneracy is not related to a non-trivial topology of the Cauchy surface.

Formation and interaction of multiple coherent phase space structures in plasma

NASA Astrophysics Data System (ADS)

Kakad, Amar; Kakad, Bharati; Omura, Yoshiharu

2017-06-01

The head-on collision of multiple counter-propagating coherent phase space structures associated with the ion acoustic solitary waves (IASWs) in plasmas composed of hot electrons and cold ions is studied here by using one-dimensional Particle-in-Cell simulation. The chains of counter-propagating IASWs are generated in the plasma by injecting the Gaussian perturbations in the equilibrium electron and ion densities. The head-on collisions of the counter-propagating electron and ion phase space structures associated with IASWs are allowed by considering the periodic boundary condition in the simulation. Our simulation shows that the phase space structures are less significantly affected by their collision with each other. They emerge out from each other by retaining their characteristics, so that they follow soliton type behavior. We also find that the electrons trapped within these IASW potentials are accelerated, while the ions are decelerated during the course of their collisions.

Augmenting Phase Space Quantization to Introduce Additional Physical Effects

NASA Astrophysics Data System (ADS)

Robbins, Matthew P. G.

Quantum mechanics can be done using classical phase space functions and a star product. The state of the system is described by a quasi-probability distribution. A classical system can be quantized in phase space in different ways with different quasi-probability distributions and star products. A transition differential operator relates different phase space quantizations. The objective of this thesis is to introduce additional physical effects into the process of quantization by using the transition operator. As prototypical examples, we first look at the coarse-graining of the Wigner function and the damped simple harmonic oscillator. By generalizing the transition operator and star product to also be functions of the position and momentum, we show that additional physical features beyond damping and coarse-graining can be introduced into a quantum system, including the generalized uncertainty principle of quantum gravity phenomenology, driving forces, and decoherence.

EXTERIOR PERSPECTIVE OF TOWER HOUSE, LOOKING SOUTHWEST. (The building’s interior ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

EXTERIOR PERSPECTIVE OF TOWER HOUSE, LOOKING SOUTHWEST. (The building’s interior space is divided into three rooms: the workshop, the mill room, and the tank house. In the tower, the original wood tank that fed water to the Harmon house and the milk house still remains.) - Engle Farm, Tank House, 89 South Ebey Road, Coupeville, Island County, WA

Spaces of Inclusion: Investigating Place, Positioning and Perspective in Educational Settings through Photo-Elicitation

ERIC Educational Resources Information Center

Dunne, Linda; Hallett, Fiona; Kay, Virginia; Woolhouse, Clare

2018-01-01

This paper presents findings from a collaborative research study which sought to explore perspectives and understandings of the concept of inclusion, as played out in schools and colleges in northwest England, via the use of images. The research had two parts: in the first part, children and young people took photographs in their school setting…

Looking Backward, Looking Forward: Forty Years of US Human Spaceflight Symposium

NASA Technical Reports Server (NTRS)

Garber, Stephen J. (Editor); Launius, Roger (Technical Monitor)

2001-01-01

This symposium reflects on forty years of U.S. Human Spaceflight, its role over the next four decades and beyond. The topics include: 1) Perspectives on the Past Forty Years of Human Spaceflight; 2) The Experience of Spaceflight; 3) Perspectives on the Next Forty Years of Human Spaceflight; and 4) The International Space Station and the Future of Human Spaceflight.

NASA's commercial research plans and opportunities

NASA Technical Reports Server (NTRS)

Arnold, Ray J.

1992-01-01

One of the primary goals of the National Aeronautics and Space Administration's (NASA) commercial space development plan is to encourage the development of space-based products and markets, along with the infrastructure and transportation that will support those products and markets. A three phased program has been instituted to carry out this program. The first phase utilizes government grants through the Centers for the Commercial Development of Space (CCDS) for space-related, industry driven research; the development of a technology data base; and the development of commercial space transportation and infrastructure. The second phase includes the development of these technologies by industry for new commercial markets, and features unique industry/government collaborations such as Joint Endeavor Agreements. The final phase will feature technical applications actually brought to the marketplace. The government's role will be to support industry required infrastructure to encourage start-up markets and industries through follow-on development agreements such as the Space Systems Development Agreement. The Office of Commercial Programs has an aggressive flight program underway on the Space Shuttle, suborbital rockets, orbital expendable launch vehicles, and the Commercial Middeck Accommodation Module with SPACEHAB Inc. The Office of Commercial Program's has been allocated 35 percent of the U.S. share of the Space Station Freedom resources for 1997 utilization. A utilization plan has been developed with the Centers for the Commercial Development of Space and has identified eleven materials processing and biotechnology payloads occupying 5 double racks in the pressurized module as well as two payloads external to the module in materials exposure and environment monitoring. The Office of Commercial Programs will rely on the Space Station Freedom to provide the long duration laboratory component for space-based commercial research.

NASA's commercial research plans and opportunities

NASA Astrophysics Data System (ADS)

Arnold, Ray J.

One of the primary goals of the National Aeronautics and Space Administration's (NASA) commercial space development plan is to encourage the development of space-based products and markets, along with the infrastructure and transportation that will support those products and markets. A three phased program has been instituted to carry out this program. The first phase utilizes government grants through the Centers for the Commercial Development of Space (CCDS) for space-related, industry driven research; the development of a technology data base; and the development of commercial space transportation and infrastructure. The second phase includes the development of these technologies by industry for new commercial markets, and features unique industry/government collaborations such as Joint Endeavor Agreements. The final phase will feature technical applications actually brought to the marketplace. The government's role will be to support industry required infrastructure to encourage start-up markets and industries through follow-on development agreements such as the Space Systems Development Agreement. The Office of Commercial Programs has an aggressive flight program underway on the Space Shuttle, suborbital rockets, orbital expendable launch vehicles, and the Commercial Middeck Accommodation Module with SPACEHAB Inc. The Office of Commercial Program's has been allocated 35 percent of the U.S. share of the Space Station Freedom resources for 1997 utilization. A utilization plan has been developed with the Centers for the Commercial Development of Space and has identified eleven materials processing and biotechnology payloads occupying 5 double racks in the pressurized module as well as two payloads external to the module in materials exposure and environment monitoring. The Office of Commercial Programs will rely on the Space Station Freedom to provide the long duration laboratory component for space-based commercial research.

Development of a Ground Test and Analysis Protocol to Support NASA's NextSTEP Phase 2 Habitation Concepts

NASA Technical Reports Server (NTRS)

Beaton, Kara H.; Chappell, Steven P.; Bekdash, Omar S.; Gernhardt, Michael L.

2018-01-01

The NASA Next Space Technologies for Exploration Partnerships (NextSTEP) program is a public-private partnership model that seeks commercial development of deep space exploration capabilities to support extensive human spaceflight missions around and beyond cislunar space. NASA first issued the Phase 1 NextSTEP Broad Agency Announcement to U.S. industries in 2014, which called for innovative cislunar habitation concepts that leveraged commercialization plans for low Earth orbit. These habitats will be part of the Deep Space Gateway (DSG), the cislunar space station planned by NASA for construction in the 2020s. In 2016, Phase 2 of the NextSTEP program selected five commercial partners to develop ground prototypes. A team of NASA research engineers and subject matter experts have been tasked with developing the ground test protocol that will serve as the primary means by which these Phase 2 prototype habitats will be evaluated. Since 2008, this core test team has successfully conducted multiple spaceflight analog mission evaluations utilizing a consistent set of operational products, tools, methods, and metrics to enable the iterative development, testing, analysis, and validation of evolving exploration architectures, operations concepts, and vehicle designs. The purpose of implementing a similar evaluation process for the NextSTEP Phase 2 Habitation Concepts is to consistently evaluate the different commercial partner ground prototypes to provide data-driven, actionable recommendations for Phase 3.

Phase space interrogation of the empirical response modes for seismically excited structures

NASA Astrophysics Data System (ADS)

Paul, Bibhas; George, Riya C.; Mishra, Sudib K.

2017-07-01

Conventional Phase Space Interrogation (PSI) for structural damage assessment relies on exciting the structure with low dimensional chaotic waveform, thereby, significantly limiting their applicability to large structures. The PSI technique is presently extended for structure subjected to seismic excitations. The high dimensionality of the phase space for seismic response(s) are overcome by the Empirical Mode Decomposition (EMD), decomposing the responses to a number of intrinsic low dimensional oscillatory modes, referred as Intrinsic Mode Functions (IMFs). Along with their low dimensionality, a few IMFs, retain sufficient information of the system dynamics to reflect the damage induced changes. The mutually conflicting nature of low-dimensionality and the sufficiency of dynamic information are taken care by the optimal choice of the IMF(s), which is shown to be the third/fourth IMFs. The optimal IMF(s) are employed for the reconstruction of the Phase space attractor following Taken's embedding theorem. The widely referred Changes in Phase Space Topology (CPST) feature is then employed on these Phase portrait(s) to derive the damage sensitive feature, referred as the CPST of the IMFs (CPST-IMF). The legitimacy of the CPST-IMF is established as a damage sensitive feature by assessing its variation with a number of damage scenarios benchmarked in the IASC-ASCE building. The damage localization capability, remarkable tolerance to noise contamination and the robustness under different seismic excitations of the feature are demonstrated.

A solvable model of Vlasov-kinetic plasma turbulence in Fourier-Hermite phase space

NASA Astrophysics Data System (ADS)

Adkins, T.; Schekochihin, A. A.

2018-02-01

A class of simple kinetic systems is considered, described by the one-dimensional Vlasov-Landau equation with Poisson or Boltzmann electrostatic response and an energy source. Assuming a stochastic electric field, a solvable model is constructed for the phase-space turbulence of the particle distribution. The model is a kinetic analogue of the Kraichnan-Batchelor model of chaotic advection. The solution of the model is found in Fourier-Hermite space and shows that the free-energy flux from low to high Hermite moments is suppressed, with phase mixing cancelled on average by anti-phase-mixing (stochastic plasma echo). This implies that Landau damping is an ineffective route to dissipation (i.e. to thermalisation of electric energy via velocity space). The full Fourier-Hermite spectrum is derived. Its asymptotics are -3/2$ at low wavenumbers and high Hermite moments ( ) and -1/2k-2$ at low Hermite moments and high wavenumbers ( ). These conclusions hold at wavenumbers below a certain cutoff (analogue of Kolmogorov scale), which increases with the amplitude of the stochastic electric field and scales as inverse square of the collision rate. The energy distribution and flows in phase space are a simple and, therefore, useful example of competition between phase mixing and nonlinear dynamics in kinetic turbulence, reminiscent of more realistic but more complicated multi-dimensional systems that have not so far been amenable to complete analytical solution.

Implementing Effective Mission Systems Engineering Practices During Early Project Formulation Phases

NASA Technical Reports Server (NTRS)

Moton, Tryshanda

2016-01-01

Developing and implementing a plan for a NASA space mission can be a complicated process. The needs, goals, and objectives of any proposed mission or technology must be assessed early in the Project Life Cycle. The key to successful development of a space mission or flight project is the inclusion of systems engineering in early project formulation, namely during Pre-phase A, Phase A, and Phase B of the NASA Project Life Cycle. When a space mission or new technology is in pre-development, or "pre-Formulation", feasibility must be determined based on cost, schedule, and risk. Inclusion of system engineering during project formulation is key because in addition to assessing feasibility, design concepts are developed and alternatives to design concepts are evaluated. Lack of systems engineering involvement early in the project formulation can result in increased risks later in the implementation and operations phases of the project. One proven method for effective systems engineering practice during the pre-Formulation Phase is the use of a mission conceptual design or technology development laboratory, such as the Mission Design Lab (MDL) at NASA's Goddard Space Flight Center (GSFC). This paper will review the engineering process practiced routinely in the MDL for successful mission or project development during the pre-Formulation Phase.

Transcranial direct current stimulation (tDCS) of the inferior frontal cortex affects the "social scaling" of extrapersonal space depending on perspective-taking ability.

PubMed

Fini, Chiara; Bardi, Lara; Epifanio, Alessandra; Committeri, Giorgia; Moors, Agnes; Brass, Marcel

2017-03-01

When we have to judge the distance between another person and an object (social condition), we judge this distance as being smaller compared to judging the distance between two objects (nonsocial condition). It has been suggested that this compression is mediated by the attribution of a motor potential to the reference frame (other person vs. object). In order to explore the neural basis of this effect, we investigated whether the modulation of activity in the inferior frontal cortex (IFC) of the left hemisphere (recruited during visuospatial processes with a social component) changes the way we categorize space in a social compared with a nonsocial condition. We applied transcranial direct current stimulation to the left IFC, with different polarities (anodal, cathodal, and sham) while subjects performed an extrapersonal space categorization task. Interestingly, anodal stimulation of IFC induced an higher compression of space in the social compared to nonsocial condition. By contrast, cathodal stimulation induced the opposite effect. Furthermore, we found that this effect is modulated by interindividual differences in cognitive perspective taking. Our data support the idea that IFC is recruited during the social categorization of space.

Generation Y Perspectives

NASA Technical Reports Server (NTRS)

Fitzpatrick, Garret; Painting, Kristen; Barrera, Aaron; Skytland, Nick

2008-01-01

Are you familiar with the famed Generation Y, or "Gen Yers?" Generation Y is projected to be 47 percent of the workforce by 2014. They were born roughly between 1977 and 2000, but that is definitely not their only defining factor. But who is this group, and what do they have to do with the future of the space program and the Johnson Space Center (JSC)? During 2007, a group of Gen Yers at JSC participated on a committee to address the NASA Headquarters strategic communications plan. Fitzpatrick, along with his co-authors, created a presentation to share the Gen Yers' perspective on their generation in conjunction with the strategic communications strategy released. This knowledge capture (KC) event is that presentation.

The Solar Dynamic radiator with a historical perspective

NASA Technical Reports Server (NTRS)

Mclallin, K. L.; Fleming, M. L.; Hoehn, F. W.; Howerton, R.

1988-01-01

A historical perspective on pumped loop space radiators provides a basis for the design of the Space Station Solar Dynamic (SD) power module radiator. SD power modules, capable of generating 25 kWe each, are planned for growth Station power requirements. The Brayton (cycle) SD module configuration incorporates a pumped loop radiator that must reject up to 99 kW. The thermal/hydraulic design conditions in combination with required radiator orientation and packaging envelope form a unique set of constraints as compared to previous pumped loop radiator systems. Nevertheless, past program successes have demonstrated a technology base which can be applied to the SD radiator development program to ensure a low risk, low cost system.

NASA's attack on costs

NASA Technical Reports Server (NTRS)

Low, George M.

1994-01-01

This article's concern is regarding the high costs of space travel and the need to minimize or reduce these costs in order to effectively provide the continuation of the space programs and space exploration needs of the future. Discussed is the possibility and need to optimize payloads in order to lower the costs associated with them. Design phase principles and implementation phase points are discussed.

Non-geometric fluxes, quasi-Hopf twist deformations, and nonassociative quantum mechanics

NASA Astrophysics Data System (ADS)

Mylonas, Dionysios; Schupp, Peter; Szabo, Richard J.

2014-12-01

We analyse the symmetries underlying nonassociative deformations of geometry in non-geometric R-flux compactifications which arise via T-duality from closed strings with constant geometric fluxes. Starting from the non-abelian Lie algebra of translations and Bopp shifts in phase space, together with a suitable cochain twist, we construct the quasi-Hopf algebra of symmetries that deforms the algebra of functions and the exterior differential calculus in the phase space description of nonassociative R-space. In this setting, nonassociativity is characterised by the associator 3-cocycle which controls non-coassociativity of the quasi-Hopf algebra. We use abelian 2-cocycle twists to construct maps between the dynamical nonassociative star product and a family of associative star products parametrized by constant momentum surfaces in phase space. We define a suitable integration on these nonassociative spaces and find that the usual cyclicity of associative noncommutative deformations is replaced by weaker notions of 2-cyclicity and 3-cyclicity. Using this star product quantization on phase space together with 3-cyclicity, we formulate a consistent version of nonassociative quantum mechanics, in which we calculate the expectation values of area and volume operators, and find coarse-graining of the string background due to the R-flux.

Space Station Furnace Facility. Volume 2: Requirements definition and conceptual design study

NASA Technical Reports Server (NTRS)

1992-01-01

The Space Station Freedom Furnace (SSFF) Project is divided into two phases: phase 1, a definition study phase, and phase 2, a design and development phase. TBE was awarded a research study entitled, 'Space Station Furnace Facility Requirements Definition and Conceptual Design Study' on June 2, 1989. This report addresses the definition study phase only. Phase 2 is to be complete after completion of phase 1. The contract encompassed a requirements definition study and culminated in hardware/facility conceptual designs and hardware demonstration development models to test these conceptual designs. The study was divided into two parts. Part 1 (the basic part of the effort) encompassed preliminary requirements definition and assessment; conceptional design of the SSFF Core; fabrication of mockups; and preparation for the support of a conceptional design review (CoDR). Part 2 (the optional part of the effort) included detailed definition of the engineering and design requirements, as derived from the science requirements; refinement of the conceptual design of the SSFF Core; fabrication and testing of the 'breadboards' or development models; and preparation for and support of a requirements definition review.

Access from Space: A New Perspective on NASA's Space Transportation Technology Requirements and Opportunities

NASA Technical Reports Server (NTRS)

Rasky, Daniel J.

2004-01-01

The need for robust and reliable access from space is clearly demonstrated by the recent loss of the Space Shuttle Columbia; as well as the NASA s goals to get the Shuttle re-flying and extend its life, build new vehicles for space access, produce successful robotic landers and s a q k retrr? llisrions, and maximize the science content of ambitious outer planets missions that contain nuclear reactors which must be safe for re-entry after possible launch aborts. The technology lynch pin of access from space is hypersonic entry systems such the thermal protection system, along with navigation, guidance and control (NG&C). But it also extends to descent and landing systems such as parachutes, airbags and their control systems. Current space access technology maturation programs such as NASA s Next Generation Launch Technology (NGLT) program or the In-Space Propulsion (ISP) program focus on maturing laboratory demonstrated technologies for potential adoption by specific mission applications. A key requirement for these programs success is a suitable queue of innovative technologies and advanced concepts to mature, including mission concepts enabled by innovative, cross cutting technology advancements. When considering space access, propulsion often dominates the capability requirements, as well as the attention and resources. From the perspective of access from space some new cross cutting technology drivers come into view, along with some new capability opportunities. These include new miniature vehicles (micro, nano, and picosats), advanced automated systems (providing autonomous on-orbit inspection or landing site selection), and transformable aeroshells (to maximize capabilities and minimize weight). This paper provides an assessment of the technology drivers needed to meet future access from space mission requirements, along with the mission capabilities that can be envisioned from innovative, cross cutting access from space technology developments.

Evaluating Uncertainty in GHG Emission Scenarios: Mapping IAM Outlooks With an Energy System Phase Space

NASA Astrophysics Data System (ADS)

Ritchie, W. J.; Dowlatabadi, H.

2017-12-01

Climate change modeling relies on projections of future greenhouse gas emissions and other phenomena leading to changes in planetary radiative forcing (RF). Pathways for long-run fossil energy use that map to total forcing outcomes are commonly depicted with integrated assessment models (IAMs). IAMs structure outlooks for 21st-century emissions with various theories for developments in demographics, economics, land-use, energy markets and energy service demands. These concepts are applied to understand global changes in two key factors relevant for scenarios of carbon emissions: total energy use (E) this century and the carbon intensity of that energy (F/E). A simple analytical and graphical approach can also illustrate the full range of outcomes for these variables to determine if IAMs provide sufficient coverage of the uncertainty space for future energy use. In this talk, we present a method for understanding uncertainties relevant to RF scenario components in a phase space. The phase space of a dynamic system represents significant factors as axes to capture the full range of physically possible states. A two-dimensional phase space of E and F/E presents the possible system states that can lead to various levels of total 21st-century carbon emissions. Once defined in this way, a phase space of these energy system coordinates allows for rapid characterization of large IAM scenario sets with machine learning techniques. This phase space method is applied to the levels of RF described by the Representative Concentration Pathways (RCPs). The resulting RCP phase space identifies characteristics of the baseline energy system outlooks provided by IAMs for IPCC Working Group III. We conduct a k-means cluster analysis to distinguish the major features of IAM scenarios for each RCP range. Cluster analysis finds the IAM scenarios in AR5 illustrate RCPs with consistent combinations of energy resources. This suggests IAM scenarios understate uncertainty ranges for future fossil energy combustion and are overly constrained, implying it is likely easier to achieve a 1.5˚ climate policy goal than previously demonstrated.

Natural environment design criteria for the space station program definition phase

NASA Technical Reports Server (NTRS)

Vaughan, W. W.

1984-01-01

The natural environment design criteria requirements for use in the Space Station and its Elements (SSPE) definition phase studies are presented. The atmospheric dynamic and thermodynamic environments, meteoroids, radiation, physical constants are addressed. It is intended to enable all groups involved in the definition phase studies to proceed with a common and consistent set of natural environment criteria requirements.

TRICHLOROETHYLENE ADSORPTION BY FIBROUS AND GRANULAR ACTIVATED CARBONS: AQUEOUS PHASE, GAS PHASE AND WATER VAPOR ADSORPTION STUDIES. (R828157)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Consumer Fraud: An Empirical Perspective. Summary.

ERIC Educational Resources Information Center

Schubert, Jane G.; And Others

The American Institutes for Research (AIR) and the National Consumer Law Center (NCLC) studied consumer fraud and assessed possible intervention. Phase I produced an AIR description of the nature, scope, and characteristics of consumer fraud and an NCLC compilation of the laws and regulations which control it. In Phase II AIR developed…

Adolescent Perspectives on Phase I Cancer Research

PubMed Central

Miller, Victoria A.; Baker, Justin N.; Leek, Angela C.; Hizlan, Sabahat; Rheingold, Susan R.; Yamokoski, Amy D.; Drotar, Dennis; Kodish, Eric

2012-01-01

Background The aim of this study was to examine adolescent patients’ perspectives on their understanding and decision making about a pediatric Phase I cancer study. Procedure Participants included adolescents ages 14-21 years with cancer (N = 20), all of whom attended a Phase I study consent conference. Participants responded to closed- and open-ended questions on a verbally administered structured interview, which assessed aspects of understanding and decision making about the Phase I study. Results All participants decided to enroll in the Phase I study. The majority of participants understood that participation was voluntary, entailed risks, and that they could withdraw. Most also believed that participation in the Phase I study would increase the length of their lives. The most frequent reasons for enrolling were positive clinical benefit, needing an option, impact on quality of life, and few side effects or fewer than those of current or past treatments. Eighty-five percent of participants reported that they themselves made the final decision about enrollment in the Phase I study. Conclusions Most participants hoped or expected that the Phase I study would provide a direct benefit (increased survival time or cure) and reported that they themselves were the final decision-maker about enrollment. Clinicians may underestimate the role of adolescents, especially if they believe that parents typically make such decisions. Future research should assess the actual participation of children and adolescents during the informed consent process and explore the role of hope in their decision making about Phase I studies. PMID:23034985

Phase-space methods for the spin dynamics in condensed matter systems

PubMed Central

Hurst, Jérôme; Manfredi, Giovanni

2017-01-01

Using the phase-space formulation of quantum mechanics, we derive a four-component Wigner equation for a system composed of spin- fermions (typically, electrons) including the Zeeman effect and the spin–orbit coupling. This Wigner equation is coupled to the appropriate Maxwell equations to form a self-consistent mean-field model. A set of semiclassical Vlasov equations with spin effects is obtained by expanding the full quantum model to first order in the Planck constant. The corresponding hydrodynamic equations are derived by taking velocity moments of the phase-space distribution function. A simple closure relation is proposed to obtain a closed set of hydrodynamic equations. This article is part of the themed issue ‘Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces’. PMID:28320903

Wigner Functions for the Bateman System on Noncommutative Phase Space

NASA Astrophysics Data System (ADS)

Heng, Tai-Hua; Lin, Bing-Sheng; Jing, Si-Cong

2010-09-01

We study an important dissipation system, i.e. the Bateman model on noncommutative phase space. Using the method of deformation quantization, we calculate the Exp functions, and then derive the Wigner functions and the corresponding energy spectra.

Flow Boiling and Condensation Experiment (FBCE) for the International Space Station

NASA Technical Reports Server (NTRS)

Mudawar, Issam; Hasan, Mohammad M.; Kharangate, Chirag; O'Neill, Lucas; Konishi, Chris; Nahra, Henry; Hall, Nancy; Balasubramaniam, R.; Mackey, Jeffrey

2015-01-01

The proposed research aims to develop an integrated two-phase flow boiling/condensation facility for the International Space Station (ISS) to serve as primary platform for obtaining two-phase flow and heat transfer data in microgravity.

Responses of Cloud Type Distributions to the Large-Scale Dynamical Circulation: Water Budget-Related Dynamical Phase Space and Dynamical Regimes

NASA Technical Reports Server (NTRS)

Wong, Sun; Del Genio, Anthony; Wang, Tao; Kahn, Brian; Fetzer, Eric J.; L'Ecuyer, Tristan S.

2015-01-01

Goals: Water budget-related dynamical phase space; Connect large-scale dynamical conditions to atmospheric water budget (including precipitation); Connect atmospheric water budget to cloud type distributions.

Phase A design study of microgravity fluoride fiber puller

NASA Technical Reports Server (NTRS)

Workman, Gary L.; Smith, Guy A.; Kosten, Susan

1994-01-01

Improved transmission properties for fluoride fibers due to space processing has great potential for commercial benefits. Phase A design study will determine conceptual feasibility and provide initial definition of the technical requirements and design issues for space.

Use of social media and online tools for participative space education and citizen science in India: Perspectives of future space leaders

NASA Astrophysics Data System (ADS)

Khan, Aafaque; Sridhar, Apoorva

2012-07-01

The previous decade saw the emergence of internet in the new avatar popularly known as Web 2.0. After its inception, Internet (also known as Web 1.0) remained centralized and propriety controlled; the information was displayed in form of static pages and users could only browse through these pages connected via URLs (Unique Resource Locator), links and search engines. Web 2.0, on the other hand, has features and tools that allow users to engage in dialogue, interact and contribute to the content on the World Wide Web. As a Result, Social Media has become the most widely accepted medium of interactive and participative dialogue around the world. Social Media is not just limited to Social Networking; it extends from podcasts, webcasts, blogs, micro-blogs, wikis, forums to crowd sourcing, cloud storage, cloud computing and Voice over Internet Protocol. World over, there is a rising trend of using Social Media for Space Education and Outreach. Governments, Space Agencies, Universities, Industry and Organizations have realized the power of Social Media to communicate advancement of space science and technology, updates on space missions and their findings to the common man as well as to the researchers, scientists and experts around the world. In this paper, the authors intend to discuss, the perspectives, of young students and professionals in the space industry on various present and future possibilities of using Social Media in space outreach and citizen science, especially in India and other developing countries. The authors share a vision for developing Social Media platforms to communicate space science and technology, along innovative ideas on participative citizen science projects for various space based applications such as earth observation and space science. Opinions of various young students and professionals in the space industry from different parts of the world are collected and reflected through a comprehensive survey. Besides, a detailed study and review with various examples of present existing projects such as Open NASA, Zooniverse, SETI, Google Earth etc. Support these perspectives. Further, the authors put light on how developing countries can benefit from Space outreach and citizen science through Social Media to connect with the society. The paper concludes with various innovative ideas that are derived from the survey and discussions with these prospective space leaders, along with the insights of the authors on future strategies for such approaches in India and other developing nations. Demographically, youth provides the largest user-base to the Social Media and these young future space leaders are expert at using Social Media in their daily life. Thus, it is important that their collective and shared opinion is presented to the present policymakers and leaders of space agencies and industry.

Probabilistic risk assessment of the Space Shuttle. Phase 3: A study of the potential of losing the vehicle during nominal operation. Volume 5: Auxiliary shuttle risk analyses

NASA Technical Reports Server (NTRS)

Fragola, Joseph R.; Maggio, Gaspare; Frank, Michael V.; Gerez, Luis; Mcfadden, Richard H.; Collins, Erin P.; Ballesio, Jorge; Appignani, Peter L.; Karns, James J.

1995-01-01

Volume 5 is Appendix C, Auxiliary Shuttle Risk Analyses, and contains the following reports: Probabilistic Risk Assessment of Space Shuttle Phase 1 - Space Shuttle Catastrophic Failure Frequency Final Report; Risk Analysis Applied to the Space Shuttle Main Engine - Demonstration Project for the Main Combustion Chamber Risk Assessment; An Investigation of the Risk Implications of Space Shuttle Solid Rocket Booster Chamber Pressure Excursions; Safety of the Thermal Protection System of the Space Shuttle Orbiter - Quantitative Analysis and Organizational Factors; Space Shuttle Main Propulsion Pressurization System Probabilistic Risk Assessment, Final Report; and Space Shuttle Probabilistic Risk Assessment Proof-of-Concept Study - Auxiliary Power Unit and Hydraulic Power Unit Analysis Report.

Space transfer vehicle concepts and requirements study. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

Weber, Gary A.

1991-01-01

A description of the study in terms of background, objectives, and issues is provided. NASA is currently studying new initiatives of space exploration involving both piloted and unpiloted missions to destinations throughout the solar system. Many of these missions require substantial improvements in launch vehicle and upper stage capabilities. This study provides a focused examination of the Space Transfer Vehicles (STV) required to perform these missions using the emerging national launch vehicle definition, the Space Station Freedom (SSF) definition, and the latest mission scenario requirements. The study objectives are to define preferred STV concepts capable of accommodating future exploration missions in a cost-effective manner, determine the technology development (if any) required to perform these missions, and develop a decision database of various programmatic approaches for the development of the STV family of vehicles. Special emphasis was given to examining space basing (stationing reusable vehicles at a space station), examining the piloted lunar mission as a primary design mission, and restricting trade studies to the high-performance, near-term cryogenics (LO2/LH2) as vehicle propellant. The study progressed through three distinct 6-month phases. The first phase concentrated on supporting a NASA 3 month definition of exploration requirements (the '90-day study') and during this phase developed and optimized the space-based point-of-departure (POD) 2.5-stage lunar vehicle. The second phase developed a broad decision database of 95 different vehicle options and transportation architectures. The final phase chose the three most cost-effective architectures and developed point designs to carry to the end of the study. These reference vehicle designs are mutually exclusive and correspond to different national choices about launch vehicles and in-space reusability. There is, however, potential for evolution between concepts.

Personality Disorder Patients' Perspectives on the Introduction of Imagery within Schema Therapy: A Qualitative Study of Patients' Experiences

ERIC Educational Resources Information Center

ten Napel-Schutz, Marieke C.; Abma, Tineke A.; Bamelis, Lotte; Arntz, Arnoud

2011-01-01

A qualitative study was done on patients' perspectives on the first phases of imagery work in the context of schema therapy (ST) for personality disorders. Patients participated in a multi-center randomized controlled study of the effectiveness of ST. Patients' experiences and opinions were collected with semistructured in-depth interviews at the…

Professor as Facilitator: Shaping an Emerging, Living System of Shared Leadership in the Classroom

ERIC Educational Resources Information Center

Bright, David S.; Turesky, Elizabeth Fisher; Putzel, Roger; Stang, Thomas

2012-01-01

From the perspective of emergence, professors can facilitate and shape a class as a complex, adaptive, and living system. A case study illustrates phases of emergence in the classroom by tracing how a professor may use this perspective to empower students to share in the leadership of the classroom. Instead of presenting lessons, the professor…

Extended Quantum Field Theory, Index Theory, and the Parity Anomaly

NASA Astrophysics Data System (ADS)

Müller, Lukas; Szabo, Richard J.

2018-06-01

We use techniques from functorial quantum field theory to provide a geometric description of the parity anomaly in fermionic systems coupled to background gauge and gravitational fields on odd-dimensional spacetimes. We give an explicit construction of a geometric cobordism bicategory which incorporates general background fields in a stack, and together with the theory of symmetric monoidal bicategories we use it to provide the concrete forms of invertible extended quantum field theories which capture anomalies in both the path integral and Hamiltonian frameworks. Specialising this situation by using the extension of the Atiyah-Patodi-Singer index theorem to manifolds with corners due to Loya and Melrose, we obtain a new Hamiltonian perspective on the parity anomaly. We compute explicitly the 2-cocycle of the projective representation of the gauge symmetry on the quantum state space, which is defined in a parity-symmetric way by suitably augmenting the standard chiral fermionic Fock spaces with Lagrangian subspaces of zero modes of the Dirac Hamiltonian that naturally appear in the index theorem. We describe the significance of our constructions for the bulk-boundary correspondence in a large class of time-reversal invariant gauge-gravity symmetry-protected topological phases of quantum matter with gapless charged boundary fermions, including the standard topological insulator in 3 + 1 dimensions.

Exploring Life Support Architectures for Evolution of Deep Space Human Exploration

NASA Technical Reports Server (NTRS)

Anderson, Molly S.; Stambaugh, Imelda C.

2015-01-01

Life support system architectures for long duration space missions are often explored analytically in the human spaceflight community to find optimum solutions for mass, performance, and reliability. But in reality, many other constraints can guide the design when the life support system is examined within the context of an overall vehicle, as well as specific programmatic goals and needs. Between the end of the Constellation program and the development of the "Evolvable Mars Campaign", NASA explored a broad range of mission possibilities. Most of these missions will never be implemented but the lessons learned during these concept development phases may color and guide future analytical studies and eventual life support system architectures. This paper discusses several iterations of design studies from the life support system perspective to examine which requirements and assumptions, programmatic needs, or interfaces drive design. When doing early concept studies, many assumptions have to be made about technology and operations. Data can be pulled from a variety of sources depending on the study needs, including parametric models, historical data, new technologies, and even predictive analysis. In the end, assumptions must be made in the face of uncertainty. Some of these may introduce more risk as to whether the solution for the conceptual design study will still work when designs mature and data becomes available.