4,652 research outputs found

    Telerobotic research at NASA Langley Research Center

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    An overview of Automation Technology Branch facilities and research is presented. Manipulator research includes dual-arm coordination studies, space manipulator dynamics, end-effector controller development, automatic space structure assembly, and the development of a dual-arm master-slave telerobotic manipulator system. Sensor research includes gravity-compensated force control, real-time monovision techniques, and laser ranging. Artificial intelligence techniques are being explored for supervisory task control, collision avoidance, and connectionist system architectures. A high-fidelity dynamic simulation of robotic systems, ROBSIM, is being supported and extended. Cooperative efforts with Oak Ridge National Laboratory have verified the ability of teleoperators to perform complex structural assembly tasks, and have resulted in the definition of a new dual-arm master-slave telerobotic manipulator. A bibliography of research results and a list of technical contacts are included

    Behavioral networks as a model for intelligent agents

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    On-going work at NASA Langley Research Center in the development and demonstration of a paradigm called behavioral networks as an architecture for intelligent agents is described. This work focuses on the need to identify a methodology for smoothly integrating the characteristics of low-level robotic behavior, including actuation and sensing, with intelligent activities such as planning, scheduling, and learning. This work assumes that all these needs can be met within a single methodology, and attempts to formalize this methodology in a connectionist architecture called behavioral networks. Behavioral networks are networks of task processes arranged in a task decomposition hierarchy. These processes are connected by both command/feedback data flow, and by the forward and reverse propagation of weights which measure the dynamic utility of actions and beliefs

    CHANGES IN POSTURE OF MEN UNDER INFLUENCE OF LOAD

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    Automation and robotics considerations for a lunar base

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    An envisioned lunar outpost shares with other NASA missions many of the same criteria that have prompted the development of intelligent automation techniques with NASA. Because of increased radiation hazards, crew surface activities will probably be even more restricted than current extravehicular activity in low Earth orbit. Crew availability for routine and repetitive tasks will be at least as limited as that envisioned for the space station, particularly in the early phases of lunar development. Certain tasks are better suited to the untiring watchfulness of computers, such as the monitoring and diagnosis of multiple complex systems, and the perception and analysis of slowly developing faults in such systems. In addition, mounting costs and constrained budgets require that human resource requirements for ground control be minimized. This paper provides a glimpse of certain lunar base tasks as seen through the lens of automation and robotic (A&R) considerations. This can allow a more efficient focusing of research and development not only in A&R, but also in those technologies that will depend on A&R in the lunar environment

    Robust concurrent remote entanglement between two superconducting qubits

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    Entangling two remote quantum systems which never interact directly is an essential primitive in quantum information science and forms the basis for the modular architecture of quantum computing. When protocols to generate these remote entangled pairs rely on using traveling single photon states as carriers of quantum information, they can be made robust to photon losses, unlike schemes that rely on continuous variable states. However, efficiently detecting single photons is challenging in the domain of superconducting quantum circuits because of the low energy of microwave quanta. Here, we report the realization of a robust form of concurrent remote entanglement based on a novel microwave photon detector implemented in the superconducting circuit quantum electrodynamics (cQED) platform of quantum information. Remote entangled pairs with a fidelity of 0.57±0.010.57\pm0.01 are generated at 200200 Hz. Our experiment opens the way for the implementation of the modular architecture of quantum computation with superconducting qubits.Comment: Main paper: 7 pages, 4 figures; Appendices: 14 pages, 9 figure

    Full-disc 13^{13}CO(1-0) mapping across nearby galaxies of the EMPIRE survey and the CO-to-H2_2 conversion factor

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    Carbon monoxide (CO) provides crucial information about the molecular gas properties of galaxies. While 12^{12}CO has been targeted extensively, isotopologues such as 13^{13}CO have the advantage of being less optically thick and observations have recently become accessible across full galaxy discs. We present a comprehensive new dataset of 13^{13}CO(1-0) observations with the IRAM 30-m telescope of the full discs of 9 nearby spiral galaxies from the EMPIRE survey at a spatial resolution of ∼\sim1.5kpc. 13^{13}CO(1-0) is mapped out to 0.7−1r250.7-1r_{25} and detected at high signal-to-noise throughout our maps. We analyse the 12^{12}CO(1-0)-to-13^{13}CO(1-0) ratio (ℜ\Re) as a function of galactocentric radius and other parameters such as the 12^{12}CO(2-1)-to-12^{12}CO(1-0) intensity ratio, the 70-to-160μ\mum flux density ratio, the star-formation rate surface density, the star-formation efficiency, and the CO-to-H2_2 conversion factor. We find that ℜ\Re varies by a factor of 2 at most within and amongst galaxies, with a median value of 11 and larger variations in the galaxy centres than in the discs. We argue that optical depth effects, most likely due to changes in the mixture of diffuse/dense gas, are favored explanations for the observed ℜ\Re variations, while abundance changes may also be at play. We calculate a spatially-resolved 13^{13}CO(1-0)-to-H2_2 conversion factor and find an average value of 1.0×10211.0\times10^{21} cm−2^{-2} (K.km/s)−1^{-1} over our sample with a standard deviation of a factor of 2. We find that 13^{13}CO(1-0) does not appear to be a good predictor of the bulk molecular gas mass in normal galaxy discs due to the presence of a large diffuse phase, but it may be a better tracer of the mass than 12^{12}CO(1-0) in the galaxy centres where the fraction of dense gas is larger.Comment: accepted for publication in MNRA

    The Dense Molecular Gas and Nuclear Activity in the ULIRG IRAS 13120-5453

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    We present new ALMA Band 7 (∼340\sim340 GHz) observations of the dense gas tracers HCN, HCO+^+, and CS in the local, single-nucleus, ultraluminous infrared galaxy IRAS 13120-5453. We find centrally enhanced HCN (4-3) emission, relative to HCO+^+ (4-3), but do not find evidence for radiative pumping of HCN. Considering the size of the starburst (0.5 kpc) and the estimated supernovae rate of ∼1.2\sim1.2 yr−1^{-1}, the high HCN/HCO+^+ ratio can be explained by an enhanced HCN abundance as a result of mechanical heating by the supernovae, though the active galactic nucleus and winds may also contribute additional mechanical heating. The starburst size implies a high ΣIR\Sigma_{IR} of 4.7×10124.7\times10^{12} L⊙L_{\odot} kpc−2^{-2}, slightly below predictions of radiation-pressure limited starbursts. The HCN line profile has low-level wings, which we tentatively interpret as evidence for outflowing dense molecular gas. However, the dense molecular outflow seen in the HCN line wings is unlikely to escape the galaxy and is destined to return to the nucleus and fuel future star formation. We also present modeling of Herschel observations of the H2_2O lines and find a nuclear dust temperature of ∼40\sim40 K. IRAS 13120-5453 has a lower dust temperature and ΣIR\Sigma_{IR} than is inferred for the systems termed "compact obscured nuclei" (such as Arp 220 and Mrk 231). If IRAS 13120-5453 has undergone a compact obscured nucleus phase, we are likely witnessing it at a time when the feedback has already inflated the nuclear ISM and diluted star formation in the starburst/AGN core.Comment: accepted for publication in ApJ, 21 pages, 11 figure

    Spatially resolved CO SLED of the Luminous Merger Remnant NGC 1614 with ALMA

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    We present high-resolution (1".0) Atacama Large Millimeter/submillimeter Array (ALMA) observations of CO (1-0) and CO (2- 1) rotational transitions toward the nearby IR-luminous merger NGC 1614 supplemented with ALMA archival data of CO (3-2), and CO (6-5) transitions. The CO (6-5) emission arises from the starburst ring (central 590 pc in radius), while the lower-JJ CO lines are distributed over the outer disk (∼\sim 3.3 kpc in radius). Radiative transfer and photon dominated region (PDR) modeling reveal that the starburst ring has a single warmer gas component with more intense far-ultraviolet radiation field (nH2n_{\rm{H_2}} ∼\sim 104.6^{4.6} cm−3^{-3}, TkinT_{\rm{kin}} ∼\sim 42 K, and G0G_{\rm{0}} ∼\sim 102.7^{2.7}) relative to the outer disk (nH2n_{\rm{H_2}} ∼\sim 105.1^{5.1} cm−3^{-3}, TkinT_{\rm{kin}} ∼\sim 22 K, and G0G_{\rm{0}} ∼\sim 100.9^{0.9}). A two-phase molecular interstellar medium with a warm and cold (>> 70 K and ∼\sim 19 K) component is also an applicable model for the starburst ring. A possible source for heating the warm gas component is mechanical heating due to stellar feedback rather than PDR. Furthermore, we find evidence for non-circular motions along the north-south optical bar in the lower-JJ CO images, suggesting a cold gas inflow. We suggest that star formation in the starburst ring is sustained by the bar-driven cold gas inflow, and starburst activities radiatively and mechanically power the CO excitation. The absence of a bright active galactic nucleus can be explained by a scenario that cold gas accumulating on the starburst ring is exhausted as the fuel for star formation, or is launched as an outflow before being able to feed to the nucleus.Comment: 20 pages, 19 figures, 2 tables, accepted for publication in Ap

    World Heart Federation Briefing on Prevention: Coronavirus Disease 2019 (COVID-19) in low-income countries

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    In December 2019, the novel coronavirus Coronavirus Disease 2019 (COVID-19) outbreak started in Wuhan, the capital of Hubei province in China. Since then it has spread to many other regions, including low-income countries. Publisher's note: Due to the pressing nature of this report, we are offering a preliminary version of it while the final version of the manuscript is in editing. As soon as the final version is ready, this will be updated accordingly
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