Helios, and not FoxP3, is the marker of activated Tregs expressing GARP/LAP

PubMed Central

Elkord, Eyad; Abd Al Samid, May; Chaudhary, Belal

2015-01-01

Regulatory T cells (Tregs) are key players of immune regulation/dysregulation both in physiological and pathophysiological settings. Despite significant advances in understanding Treg function, there is still a pressing need to define reliable and specific markers that can distinguish different Treg subpopulations. Herein we show for the first time that markers of activated Tregs [latency associated peptide (LAP) and glycoprotein A repetitions predominant (GARP, or LRRC32)] are expressed on CD4+FoxP3− T cells expressing Helios (FoxP3−Helios+) in the steady state. Following TCR activation, GARP/LAP are up-regulated on CD4+Helios+ T cells regardless of FoxP3 expression (FoxP3+/−Helios+). We show that CD4+GARP+/−LAP+ Tregs make IL-10 immunosuppressive cytokine but not IFN-γ effector cytokine. Further characterization of FoxP3/Helios subpopulations showed that FoxP3+Helios+ Tregs proliferate in vitro significantly less than FoxP3+Helios− Tregs upon TCR stimulation. Unlike FoxP3+Helios− Tregs, FoxP3+Helios+ Tregs secrete IL-10 but not IFN-γ or IL-2, confirming they are bona fide Tregs with immunosuppressive characteristics. Taken together, Helios, and not FoxP3, is the marker of activated Tregs expressing GARP/LAP, and FoxP3+Helios+ Tregs have more suppressive characteristics, compared with FoxP3+Helios− Tregs. Our work implies that therapeutic modalities for treating autoimmune and inflammatory diseases, allergies and graft rejection should be designed to induce and/or expand FoxP3+Helios+ Tregs, while therapies against cancers or infectious diseases should avoid such expansion/induction. PMID:26343373

HELIOS dual swept frequency radiometer

NASA Technical Reports Server (NTRS)

White, J. R.

1975-01-01

The HELIOS dual swept frequency radiometer, used in conjunction with a dipole antenna, was designed to measure electromagnetic radiation in space. An engineering prototype was fabricated and tested on the HELIOS spacecraft. Two prototypes and two flight units were fabricated and three of the four units were integrated into the HELIOS spacecraft. Two sets of ground support equipment were provided for checkout of the radiometer.

Update and evaluation of decay data for spent nuclear fuel analyses

NASA Astrophysics Data System (ADS)

Simeonov, Teodosi; Wemple, Charles

2017-09-01

Studsvik's approach to spent nuclear fuel analyses combines isotopic concentrations and multi-group cross-sections, calculated by the CASMO5 or HELIOS2 lattice transport codes, with core irradiation history data from the SIMULATE5 reactor core simulator and tabulated isotopic decay data. These data sources are used and processed by the code SNF to predict spent nuclear fuel characteristics. Recent advances in the generation procedure for the SNF decay data are presented. The SNF decay data includes basic data, such as decay constants, atomic masses and nuclide transmutation chains; radiation emission spectra for photons from radioactive decay, alpha-n reactions, bremsstrahlung, and spontaneous fission, electrons and alpha particles from radioactive decay, and neutrons from radioactive decay, spontaneous fission, and alpha-n reactions; decay heat production; and electro-atomic interaction data for bremsstrahlung production. These data are compiled from fundamental (ENDF, ENSDF, TENDL) and processed (ESTAR) sources for nearly 3700 nuclides. A rigorous evaluation procedure of internal consistency checks and comparisons to measurements and benchmarks, and code-to-code verifications is performed at the individual isotope level and using integral characteristics on a fuel assembly level (e.g., decay heat, radioactivity, neutron and gamma sources). Significant challenges are presented by the scope and complexity of the data processing, a dearth of relevant detailed measurements, and reliance on theoretical models for some data.

Daddy, where did (PS)I come from?

PubMed

Baymann, F; Brugna, M; Mühlenhoff, U; Nitschke, W

2001-10-30

The reacton centre I (RCI)-type photosystems from plants, cyano-, helio- and green sulphur bacteria are compared and the essential properties of an archetypal RCI are deduced. Species containing RCI-type photosystems most probably cluster together on a common branch of the phylogenetic tree. The predicted branching order is green sulphur, helio- and cyanobacteria. Striking similarities between RCI- and RCII-type photosystems recently became apparent in the three-dimensional structures of photosystem I (PSI), PSII and RCII. The phylogenetic relationship between all presently known photosystems is analysed suggesting (a) RCI as the ancestral photosystem and (b) the descendence of PSII from RCI via gene duplication and gene splitting. An evolutionary model trying to rationalise available data is presented.

Mathematical Formulation used by MATLAB Code to Convert FTIR Interferograms to Calibrated Spectra

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

Armstrong, Derek Elswick

This report discusses the mathematical procedures used to convert raw interferograms from Fourier transform infrared (FTIR) sensors to calibrated spectra. The work discussed in this report was completed as part of the Helios project at Los Alamos National Laboratory. MATLAB code was developed to convert the raw interferograms to calibrated spectra. The report summarizes the developed MATLAB scripts and functions, along with a description of the mathematical methods used by the code. The first step in working with raw interferograms is to convert them to uncalibrated spectra by applying an apodization function to the raw data and then by performingmore » a Fourier transform. The developed MATLAB code also addresses phase error correction by applying the Mertz method. This report provides documentation for the MATLAB scripts.« less

The component-based architecture of the HELIOS medical software engineering environment.

PubMed

Degoulet, P; Jean, F C; Engelmann, U; Meinzer, H P; Baud, R; Sandblad, B; Wigertz, O; Le Meur, R; Jagermann, C

1994-12-01

The constitution of highly integrated health information networks and the growth of multimedia technologies raise new challenges for the development of medical applications. We describe in this paper the general architecture of the HELIOS medical software engineering environment devoted to the development and maintenance of multimedia distributed medical applications. HELIOS is made of a set of software components, federated by a communication channel called the HELIOS Unification Bus. The HELIOS kernel includes three main components, the Analysis-Design and Environment, the Object Information System and the Interface Manager. HELIOS services consist in a collection of toolkits providing the necessary facilities to medical application developers. They include Image Related services, a Natural Language Processor, a Decision Support System and Connection services. The project gives special attention to both object-oriented approaches and software re-usability that are considered crucial steps towards the development of more reliable, coherent and integrated applications.

Data reduction and analysis of HELIOS plasma wave data

NASA Technical Reports Server (NTRS)

Anderson, Roger R.

1988-01-01

Reduction of data acquired from the HELIOS Solar Wind Plasma Wave Experiments on HELIOS 1 and 2 was continued. Production of 24 hour survey plots of the HELIOS 1 plasma wave data were continued and microfilm copies were submitted to the National Space Science Data Center. Much of the effort involved the shock memory from both HELIOS 1 and 2. This data had to be deconvoluted and time ordered before it could be displayed and plotted in an organized form. The UNIVAX 418-III computer was replaced by a DEC VAX 11/780 computer. In order to continue the reduction and analysis of the data set, all data reduction and analysis computer programs had to be rewritten.

Characteristics of CMEs observed in the heliosphere using Helios photometer data. [coronal mass ejection

NASA Technical Reports Server (NTRS)

Webb, D. F.; Jackson, B. V.

1992-01-01

The zodiacal light photometers on the two Helios spacecraft have been used to detect and study mass ejections and other phenomena emanating from the sun and traversing the heliosphere within 1 AU. We have recently compiled a complete list of all of the significant white light transient events detected from the 90-deg photometers on both Helios spacecraft. This is a preliminary report on the long-term frequency of occurrence of these events; it emphasizes newly processed data from Helios-l from 1975 through 1982 and viewed south of the ecliptic. With the large Helios photometer data base, we will be able to identify the fraction of the 90 deg events which are heliospheric CMEs and determine their characteristics.

Instability of Helios-deficient Tregs is associated with conversion to a T-effector phenotype and enhanced antitumor immunity.

PubMed

Nakagawa, Hidetoshi; Sido, Jessica M; Reyes, Edwin E; Kiers, Valerie; Cantor, Harvey; Kim, Hye-Jung

2016-05-31

Expression of the transcription factor Helios by Tregs ensures stable expression of a suppressive and anergic phenotype in the face of intense inflammatory responses, whereas Helios-deficient Tregs display diminished lineage stability, reduced FoxP3 expression, and production of proinflammatory cytokines. Here we report that selective Helios deficiency within CD4 Tregs leads to enhanced antitumor immunity through induction of an unstable phenotype and conversion of intratumoral Tregs into T effector cells within the tumor microenvironment. Induction of an unstable Treg phenotype is associated with enhanced production of proinflammatory cytokines by tumor-infiltrating but not systemic Tregs and significantly delayed tumor growth. Ab-dependent engagement of Treg surface receptors that result in Helios down-regulation also promotes conversion of intratumoral but not systemic Tregs into T effector cells and leads to enhanced antitumor immunity. These findings suggest that selective instability and conversion of intratumoral CD4 Tregs through genetic or Ab-based targeting of Helios may represent an effective approach to immunotherapy.

Helios: Understanding Solar Evolution Through Text Analytics

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

Randazzese, Lucien

This proof-of-concept project focused on developing, testing, and validating a range of bibliometric, text analytic, and machine-learning based methods to explore the evolution of three photovoltaic (PV) technologies: Cadmium Telluride (CdTe), Dye-Sensitized solar cells (DSSC), and Multi-junction solar cells. The analytical approach to the work was inspired by previous work by the same team to measure and predict the scientific prominence of terms and entities within specific research domains. The goal was to create tools that could assist domain-knowledgeable analysts in investigating the history and path of technological developments in general, with a focus on analyzing step-function changes in performance,more » or “breakthroughs,” in particular. The text-analytics platform developed during this project was dubbed Helios. The project relied on computational methods for analyzing large corpora of technical documents. For this project we ingested technical documents from the following sources into Helios: Thomson Scientific Web of Science (papers), the U.S. Patent & Trademark Office (patents), the U.S. Department of Energy (technical documents), the U.S. National Science Foundation (project funding summaries), and a hand curated set of full-text documents from Thomson Scientific and other sources.« less

HelioScan: a software framework for controlling in vivo microscopy setups with high hardware flexibility, functional diversity and extendibility.

PubMed

Langer, Dominik; van 't Hoff, Marcel; Keller, Andreas J; Nagaraja, Chetan; Pfäffli, Oliver A; Göldi, Maurice; Kasper, Hansjörg; Helmchen, Fritjof

2013-04-30

Intravital microscopy such as in vivo imaging of brain dynamics is often performed with custom-built microscope setups controlled by custom-written software to meet specific requirements. Continuous technological advancement in the field has created a need for new control software that is flexible enough to support the biological researcher with innovative imaging techniques and provide the developer with a solid platform for quickly and easily implementing new extensions. Here, we introduce HelioScan, a software package written in LabVIEW, as a platform serving this dual role. HelioScan is designed as a collection of components that can be flexibly assembled into microscope control software tailored to the particular hardware and functionality requirements. Moreover, HelioScan provides a software framework, within which new functionality can be implemented in a quick and structured manner. A specific HelioScan application assembles at run-time from individual software components, based on user-definable configuration files. Due to its component-based architecture, HelioScan can exploit synergies of multiple developers working in parallel on different components in a community effort. We exemplify the capabilities and versatility of HelioScan by demonstrating several in vivo brain imaging modes, including camera-based intrinsic optical signal imaging for functional mapping of cortical areas, standard two-photon laser-scanning microscopy using galvanometric mirrors, and high-speed in vivo two-photon calcium imaging using either acousto-optic deflectors or a resonant scanner. We recommend HelioScan as a convenient software framework for the in vivo imaging community. Copyright © 2013 Elsevier B.V. All rights reserved.

Development and Implementation of a New HELIOS Diagnostic using a Fast Piezoelectric Valve on the Prototype Material Plasma Exposure eXperiment

NASA Astrophysics Data System (ADS)

Ray, Holly; Biewer, Theodore; Caneses, Juan; Green, Jonathan; Lindquist, Elizabeth; McQuown, Levon; Schmitz, Oliver

2017-10-01

A new helium line-ratio spectral monitoring (HELIOS) diagnostic, using a piezoelectric valve with high duty cycles (on/off times ms), allowing for good background correction, and measured particle flowrates on the order of 1020 particles/second is being implemented on Oak Ridge National Laboratory's (ORNL) Prototype Material Plasma Exposure eXperiment (Proto-MPEX). Built in collaboration with the University of Wisconsin - Madison, the HELIOS diagnostic communicates with a Labview program for controlled bursts of helium into the vessel. The open magnetic geometry of Proto-MPEX is ideal for testing and characterizing a HELIOS diagnostic. The circular cross-section with four ports allows for cross comparison between different diagnostics: 1) Helium injection with the piezoelectric puff valve, 2) HELIOS line-of-sight high-gain observation, 3) scan-able Double Langmuir probe, and 4) HELIOS 2D imaging observation. Electron density and temperature measurements from the various techniques will be compared. This work was supported by the US. D.O.E. contract DE-AC05-00OR22725 and DE-SC00013911.

Interplanetary Alfvenic fluctuations: A statistical study of the directional variations of the magnetic field

NASA Technical Reports Server (NTRS)

Bavassano, B.; Mariani, F.

1983-01-01

Magnetic field data from HELIOS 1 and 2 are used to test a stochastic model for Alfvenic fluctuations recently proposed. A reasonable matching between observations and predictions is found. A rough estimate of the correlation length of the observed fluctuations is inferred.

HELIOS Third Joint Working Group Meeting

NASA Technical Reports Server (NTRS)

Ousley, Gilbert; Kutzer, Ants

1970-01-01

During the past six months since the Second Helios Joint Working Group Meeting held 27-30 April 1970 at Goddard Space Flight Center, the TDS Sub-Group supported the Helios Project Office and the other Sub-Groups in the timely disposition of action items and the dissemination of information pertinent to the development of interface documentation. Of particular importance during this time period was the Project's decision to incorporate a single-channel telemetry system design aboard the spacecraft. The TDS Sub-Group participated actively in the process that led to this decision. Still under active study with TDS participation is the pending Project Office decision regarding the incorporation of a ranging capability within the telecommunications design. The TDS Sub-Group assisted the Mission Analysis and Operations Sub-Group in establishment of a study effort concerning the Near-Earth Sequence of Events from launch to launch plus 8 hours. This study, which will provide valuable data for the spacecraft telecommunications design, will include participation by the Experiment, Launch Vehicle, Spacecraft, as well as the TDS and MA&O Sub-Groups. Also during the past 6-month period, the TDS, in conjunction with the Spacecraft Sub-Group, initiated activity to develop the Helios Spacecraft/TDS Compatibility Test Plans and Procedures. Activity concerning the foregoing interface discussions has been and will continue to be based upon the "TDS Estimated Capabilities Document for the Helios Missions" (613-1), and the "DSN/Flight Project Interface Design Handbook" (810-5). These will continue to be considered TDS controlling documents until specific Helios Project/TDS interface documentation is generated and signed off by the respective parties. In addition to the above, the DSN continued the Helios Trainee Program with seven GfW/DFVLR trainees in residence at JPL. Two trainees will complete their year's residency concurrent with the Third Helios Joint Working Group Meeting, while four new trainees are expected to arrive following the Third Helios Joint Working Group Meeting. These and other activities are reported in detail in the paragraphs that follow.

Association of Regulatory T Cells with Diabetes Type-1 and Its Renal and Vascular Complications Based on the Expression of Forkhead Box Protein P3 (FoxP3), Helios and Neurophilin-1.

PubMed

Khamechian, Tahereh; Irandoust, Behnaz; Mohammadi, Hanieh; Nikoueinejad, Hassan; Akbari, Hossein

2018-04-01

In recent years, it has been recognized that regulatory T cells (Tregs) play a critical role in maintaining immune tolerance. Moreover, the expression of two markers named Helios and neurophilin-1 (NRP-1) has been highlighted in such cells. Helios, an intracellular transcription marker, largely differentiates twomost operative sub group of Tregs, namely naturally occurring (nTreg) and induced (iTreg) Tregs, and NRP-1 is reckoned as a membranous activity marker of Tregs. We aimed to count peripheral mononuclear cells expressing such markers in a group of type 1 diabetes patients to elucidate the possible role of Tregs in the pathogenesis of such disease and its complications. Blood samples from 61 adult patients with type 1 diabetes and 61 sex and age-matched healthy controls were tested to count two types of Tregs, namely naturally occurring and inducible types, according to the expression of cell surface markers of CD4/CD25/CD47-FITC/PE/APC and intracellular markers of FoxP3/Helios-PE-CY5/eFlour450 by flow cytometry, respectively.We also investigated the relation between expression of such markers with HbA1c, urine albumin/creatinine ratio (UACR), and common carotid intima thickness (CIMT). The circulatory frequency of both Helios+ and Helios- T-cells were significantly decreased in patients compared to those in healthy controls (p<0.001). There was also a significant decrease in circulatory frequency of Helios+ NRP-1+ and Helios- NRP-1+ cells in the patients compared to controls (p=0.029). According to expression of Helios and NRP-1 markers, the number and function of both Tregs were decreased in diabetic patients. Moreover, the neurophilin expression was inversely associated with complications of type 1 diabetes.

Tracking and data systems support for the Helios project. Volume 1: Project development through end of mission, phase 2

NASA Technical Reports Server (NTRS)

Goodwin, P. S.; Traxler, M. R.; Meeks, W. G.; Flanagan, F. M.

1976-01-01

The overall evolution of the Helios Project is summarized from its conception through to the completion of the Helios-1 mission phase 2. Beginning with the project objectives and concluding with the Helios-1 spacecraft entering its first superior conjunction (end of mission phase 2), descriptions of the project, the mission and its phases, international management and interfaces, and Deep Space Network-spacecraft engineering development in telemetry, tracking, and command systems to ensure compatibility between the U.S. Deep Space Network and the German-built spacecraft are included.

The effects of solarization on the performance of a gas turbine

NASA Astrophysics Data System (ADS)

Homann, Christiaan; van der Spuy, Johan; von Backström, Theodor

2016-05-01

Various hybrid solar gas turbine configurations exist. The Stellenbosch University Solar Power Thermodynamic (SUNSPOT) cycle consists of a heliostat field, solar receiver, primary Brayton gas turbine cycle, thermal storage and secondary Rankine steam cycle. This study investigates the effect of the solarization of a gas turbine on its performance and details the integration of a gas turbine into a solar power plant. A Rover 1S60 gas turbine was modelled in Flownex, a thermal-fluid system simulation and design code, and validated against a one-dimensional thermodynamic model at design input conditions. The performance map of a newly designed centrifugal compressor was created and implemented in Flownex. The effect of the improved compressor on the performance of the gas turbine was evident. The gas turbine cycle was expanded to incorporate different components of a CSP plant, such as a solar receiver and heliostat field. The solarized gas turbine model simulates the gas turbine performance when subjected to a typical variation in solar resource. Site conditions at the Helio100 solar field were investigated and the possibility of integrating a gas turbine within this system evaluated. Heat addition due to solar irradiation resulted in a decreased fuel consumption rate. The influence of the additional pressure drop over the solar receiver was evident as it leads to decreased net power output. The new compressor increased the overall performance of the gas turbine and compensated for pressure losses incurred by the addition of solar components. The simulated integration of the solarized gas turbine at Helio100 showed potential, although the solar irradiation is too little to run the gas turbine on solar heat alone. The simulation evaluates the feasibility of solarizing a gas turbine and predicts plant performance for such a turbine cycle.

ED03-0152-1

NASA Image and Video Library

2003-06-07

The first flight of a large aircraft to be powered by electric fuel cells began with a takeoff at 8:43 a.m. HST today from the Hawaiian island of Kauai. The Helios Prototype flying wing, built by AeroVironment, Inc., of Monrovia, Calif., as part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program, used solar panels to power its 10 electric motors for takeoff and during daylight portions of its planned 20-hour shakedown flight. As sunlight diminishes, Helios will switch to a fuel cell system to continue flight into the night. The takeoff set the stage for a two-day Helios endurance flight in the stratosphere planned for mid-July. The Helios wing, spanning 247 feet and weighing about 2,400 pounds, gave NASA and industry engineers confidence that remotely piloted aircraft would be able to stay aloft for weeks at a time, providing environmental monitoring capabilities and telecommunications relay services. Helios was an all-electric airplane. In addition to being non-polluting, Helios flew above storms, and used the power of the sun to stay aloft during daylight. Key to the success of this type of aircraft was the ability to fly in darkness, using fuel cells when sunlight cannot furnish energy. Helios flew over the Navy's Pacific Missile Range Facility where favorable sun exposure and test ranges closed to other air traffic benefited the NASA research effort. In 2003 the aircraft was lost to a crash.

Interplanetary baseline observations of type 3 solar radio bursts. [by Helios satellites

NASA Technical Reports Server (NTRS)

Weber, R. R.; Fitzenreiter, R. J.; Novaco, J. C.; Fainberg, J.

1977-01-01

Simultaneous observations of type III radio bursts using spacecraft separated by several tenths of an AU were made using the solar orbiters HELIOS-A and -B. The burst beginning at 1922 UT on March 28, 1976, was located from the intersection of the source directions measured at each spacecraft, and from the burst arrival time differences. Wide baseline observations give the radial distance of the source at each observing frequency. Consequently, coronal electron densities and exciter velocity were determined directly, without the need to assume a density model as is done with single spacecraft observations. The separation of HELIOS-A and -B also provided the first measurements of burst directivity at low frequencies. For the March 28 burst, the intensity observed from near the source longitude (HELIOS-B) was significantly greater than from 60 W of the source (HELIOS-A).

ED03-0152-60

NASA Image and Video Library

2003-06-07

The takeoff set the stage for a two-day Helios endurance flight in the stratosphere planned for mid-July. The Helios wing, spanning 247 feet and weighing about 2,400 pounds, is giving NASA and industry engineers confidence that remotely piloted aircraft will be able to stay aloft for weeks at a time, providing environmental monitoring capabilities and telecommunications relay services Helios is an all-electric airplane. In addition to being non-polluting, Helios can fly above storms, and use the power of the sun to stay aloft during daylight. Key to the success of this type of aircraft is the ability to fly in darkness, using fuel cells when sunlight cannot furnish energy. Helios flew over the Navy's Pacific Missile Range Facility where favorable sun exposure and test ranges closed to other air traffic benefited the NASA research effort. In 2003 the aircraft was lost to a crash.

Use Of Zernike Polynomials And Interferometry In The Optical Design And Assembly Of Large Carbon-Dioxide Laser Systems

NASA Astrophysics Data System (ADS)

Viswanathan, V. K.

1982-02-01

This paper describes the need for non-raytracing schemes in the optical design and analysis of large carbon-dioxide lasers like the Gigawatt,1 Gemini, 2 and Helios3 lasers currently operational at Los Alamos, and the Antares 4 laser fusion system under construction. The scheme currently used at Los Alamos involves characterizing the various optical components with a Zernike polynomial sets obtained by the digitization6 of experimentally produced interferograms of the components. A Fast Fourier Transform code then propagates the complex amplitude and phase of the beam through the whole system and computes the optical parameters of interest. The analysis scheme is illustrated through examples of the Gigawatt, Gemini, and Helios systems. A possible way of using the Zernike polynomials in optical design problems of this type is discussed. Comparisons between the computed values and experimentally obtained results are made and it is concluded that this appears to be a valid approach. As this is a review article, some previously published results are also used where relevant.

Tracking and data systems support for the Helios project. Volume 3: DSN support of Project Helios May 1976 - June 1977

NASA Technical Reports Server (NTRS)

Goodwin, P. S.; Jensen, W. N.; Flanagan, F. M.

1979-01-01

Spacecraft extended mission coverage does not generally carry a high priority, but Helios was fortunate in that a combination of separated viewperiods and unique utilization of the STDN Goldstone antenna have provided a considerable amount of additional science data return, particularly at key times such a perihelion and/or solar occultation.

ED03-0152-2

NASA Image and Video Library

2003-06-07

The first flight of a large aircraft to be powered by electric fuel cells began with a takeoff at 8:43 a.m. HST today from the Hawaiian island of Kauai. The Helios Prototype flying wing, built by AeroVironment, Inc., of Monrovia, Calif., as part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program, used solar panels to power its 10 electric motors for takeoff and during daylight portions of its planned 20-hour shakedown flight. As sunlight diminishes, Helios will switch to a fuel cell system to continue flight into the night. The takeoff set the stage for a two-day Helios endurance flight in the stratosphere planned for mid-July. The Helios wing, spanning 247 feet and weighing about 2,400 pounds, is giving NASA and industry engineers confidence that remotely piloted aircraft will be able to stay aloft for weeks at a time, providing environmental monitoring capabilities and telecommunications relay services. Helios is an all-electric airplane. In addition to being non-polluting, Helios can fly above storms, and use the power of the sun to stay aloft during daylight. Key to the success of this type of aircraft is the ability to fly in darkness, using fuel cells when sunlight cannot furnish energy. Helios flew over the Navy's Pacific Missile Range Facility where favorable sun exposure and test ranges closed to other air traffic benefited the NASA research effort. In 2003 the aircraft was lost to a crash.

ED03-0152-4

NASA Image and Video Library

2003-06-07

The first flight of a large aircraft to be powered by electric fuel cells began with a takeoff at 8:43 a.m. HST today from the Hawaiian island of Kauai. The Helios Prototype flying wing, built by AeroVironment, Inc., of Monrovia, Calif., as part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program, used solar panels to power its 10 electric motors for takeoff and during daylight portions of its planned 20-hour shakedown flight. As sunlight diminishes, Helios will switch to a fuel cell system to continue flight into the night. The takeoff set the stage for a two-day Helios endurance flight in the stratosphere planned for mid-July. The Helios wing, spanning 247 feet and weighing about 2,400 pounds, is giving NASA and industry engineers confidence that remotely piloted aircraft will be able to stay aloft for weeks at a time, providing environmental monitoring capabilities and telecommunications relay services. Helios is an all-electric airplane. In addition to being non-polluting, Helios can fly above storms, and use the power of the sun to stay aloft during daylight. Key to the success of this type of aircraft is the ability to fly in darkness, using fuel cells when sunlight cannot furnish energy. Helios flew over the Navy's Pacific Missile Range Facility where favorable sun exposure and test ranges closed to other air traffic benefited the NASA research effort. In 2003 the aircraft was lost to a crash.

ED03-0152-3

NASA Image and Video Library

2003-06-07

The first flight of a large aircraft to be powered by electric fuel cells began with a takeoff at 8:43 a.m. HST today from the Hawaiian island of Kauai. The Helios Prototype flying wing, built by AeroVironment, Inc., of Monrovia, Calif., as part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program, used solar panels to power its 10 electric motors for takeoff and during daylight portions of its planned 20-hour shakedown flight. As sunlight diminishes, Helios will switch to a fuel cell system to continue flight into the night. The takeoff set the stage for a two-day Helios endurance flight in the stratosphere planned for mid-July. The Helios wing, spanning 247 feet and weighing about 2,400 pounds, is giving NASA and industry engineers confidence that remotely piloted aircraft will be able to stay aloft for weeks at a time, providing environmental monitoring capabilities and telecommunications relay services. Helios is an all-electric airplane. In addition to being non-polluting, Helios can fly above storms, and use the power of the sun to stay aloft during daylight. Key to the success of this type of aircraft is the ability to fly in darkness, using fuel cells when sunlight cannot furnish energy. Helios flew over the Navy's Pacific Missile Range Facility where favorable sun exposure and test ranges closed to other air traffic benefited the NASA research effort. In 2003 the aircraft was lost to a crash.

ED03-0152-32

NASA Image and Video Library

2003-06-07

The first flight of a large aircraft to be powered by electric fuel cells began with a takeoff at 8:43 a.m. HST today from the Hawaiian island of Kauai. The Helios Prototype flying wing, built by AeroVironment, Inc., of Monrovia, Calif., as part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program, used solar panels to power its 10 electric motors for takeoff and during daylight portions of its planned 20-hour shakedown flight. As sunlight diminishes, Helios will switch to a fuel cell system to continue flight into the night. The takeoff set the stage for a two-day Helios endurance flight in the stratosphere planned for mid-July. The Helios wing, spanning 247 feet and weighing about 2,400 pounds, is giving NASA and industry engineers confidence that remotely piloted aircraft will be able to stay aloft for weeks at a time, providing environmental monitoring capabilities and telecommunications relay services. Helios is an all-electric airplane. In addition to being non-polluting, Helios can fly above storms, and use the power of the sun to stay aloft during daylight. Key to the success of this type of aircraft is the ability to fly in darkness, using fuel cells when sunlight cannot furnish energy. Helios flew over the Navy's Pacific Missile Range Facility where favorable sun exposure and test ranges closed to other air traffic benefited the NASA research effort. In 2003 the aircraft was lost to a crash.

The Helios Faraday Rotation Data Archive

NASA Astrophysics Data System (ADS)

Bird, M. K.; Volland, H.; Levy, G. S.; Stelzried, C. T.; Seidel, B. L.; Efimov, A. I.; Andreev, V. E.; Samoznaev, L. N.

2003-09-01

The Helios Faraday Rotation (FR) Experiment, a passive radio science investigation requiring no on-board hardware other than the existing spacecraft radio subsystem, was designed to study the dynamic and quiescent structure of the magnetic fields and electron density in the solar corona. Measurements of coronal Faraday rotation were derived from the linearly polarized S-band downlink carrier signal, which probed otherwise inaccessible regions of the corona in the radial range from 2 to 15 solar radii during the regularly recurring solar conjunctions. More than 1250 hours of Helios FR data were recorded over the duration of the Helios 1 (1974-84) and Helios 2 (1976-80) missions. The time scales of FR variations provide information on various physical phenomena: (a) slowly-varying rise and fall associated with the changing ray path offset, combined with the rotation of the quasi-static corona; (b) ubiquitous random oscillations with higher fluctuation amplitude at smaller solar offset distances, probably caused by coronal Alfvén waves; (c) occasional nearly discontinous jumps in the polarization angle, most likely caused by transient events such as coronal mass ejections (CMEs). The Helios FR data, aspects of which have been reported in more than forty publications to date, have now been systematically collected in a data archive for public dissemination. A brief review of the main results of the Helios FR Experiment are presented, together with some suggestions for possible use of the archive for continued solar wind research.

The Outdoor Atmospheric Simulation Chamber of Orleans-France (HELIOS)

NASA Astrophysics Data System (ADS)

Mellouki, A.; Véronique, D.; Grosselin, B.; Peyroux, F.; Benoit, R.; Ren, Y.; Idir, M.

2016-12-01

Atmospheric simulation chambers are among the most advanced tools for investigating the atmospheric processes to derive physico-chemical parameters which are required for air quality and climate models. Recently, the ICARE-CNRS at Orléans (France) has set up a new large outdoor simulation chamber, HELIOS. HELIOS is one of the most advanced simulation chambers in Europe. It is one of the largest outdoor chambers and is especially suited to processes studies performed under realistic atmospheric conditions. HELIOS is a large hemispherical outdoor simulation chamber (volume of 90 m3) positioned on the top of ICARE-CNRS building at Orléans (47°50'18.39N; 1°56'40.03E). The chamber is made of FEP film ensuring more than 90 % solar light transmission. The chamber is protected against severe meteorological conditions by a moveable "box" which contains a series of Xenon lamps enabling to conduct experiments using artificial light. This special design makes HELIOS a unique platform where experiments can be made using both types of irradiations. HELIOS is dedicated mainly to the investigation of the chemical processes under different conditions (sunlight, artificial light and dark). The platform allows conducting the same type of experiments under both natural and artificial light irradiation. The available large range of complementary and highly sensitive instruments allows investigating the radical chemistry, gas phase processes and aerosol formation under realistic conditions. The characteristics of HELIOS will be presented as well as the first series of experimental results obtained so far.

Titan/Centaur D-1TTC-5 Helios B flight data report

NASA Technical Reports Server (NTRS)

Adams, K. A.

1976-01-01

The fourth operational flight of the newest NASA unmanned launch vehicle is reported. The spacecraft was the Helios B, the second of two solar probes designed and built by the Federal Republic of Germany. The primary mission objective, to place the Helios spacecraft on a heliocentric orbit in the ecliptic plane with a perihelion distance of 0.29 AU, was successfully accomplished. After successful injection of the Helios spacecraft, a series of experiments were performed with the Centaur stage to demonstrate its operational capabilities. All objectives of the extended mission phase were successfully met. This report presents the analysis of the launch vehicle flight data for the primary mission phase of the TC-5 flight.

Interplanetary baseline observations of type III solar radio bursts

NASA Technical Reports Server (NTRS)

Weber, R. R.; Fitzenreiter, R. J.; Novaco, J. C.; Fainberg, J.

1977-01-01

Simultaneous observations of type III radio bursts from spacecraft separated by 0.43 AU have been made using the solar orbiters Helios-A and Helios-B. The burst beginning at 19:22 UT on March 28, 1976, has been located from the intersection of the source directions measured at each spacecraft and from burst arrival-time differences. The source positions range from 0.03 AU from the sun at 3000 kHz to 0.08 AU at 585 kHz. The electron density along the burst trajectory and the exciter velocity (0.13c) were determined directly without the need to assume a density model, as has been done with single-spacecraft observations. The separation of Helios-A and -B has also provided measurements of burst directivity at low frequencies. For the March 28 burst the intensity observed from near the source longitude (Helios-B) was 3-10dB greater than that from 60 deg west of the source (Helios-A)

A Single and Comprehensive Helios Data Archive

NASA Astrophysics Data System (ADS)

Salem, C. S.

2017-12-01

Helios 1 & 2 rank amoung the most important missions in Heliophysics, and the more-than 11 years of data returned by its spacecraft remain of paramount interests to researchers. Their unique trajectories which brought them closer to the Sun than any spaceccraft before or since, enabled their diverse suite of in-situ instruments to return measurements of unprecedented scientific richness. There is however no comprehensive public repository of all Helios in-situ data. Currently, most of the highest resolution data can be obtained from a variety of places, although highly processed and with very little documentation, especially on calibration. Analysis of this data set requires overcoming a number of technical and instrumental issues, knowledge and expertise of which is only possessed by the original PI's of the Helios experiments. We present here a work funded by NASA of aggregating, analyzing, evaluating, documenting and archiving the available Helios 1 and 2 in-situ data. This work at the UC Berkeley Space Sciences Laboratory is being undertaken in close collaboration with colleagues at the University of Koln, at the University of Kiel, at the Imperial College in London and at the Paris Observatory. A careful, detailed, analysis of the Helios fluxgate and search coil magnetic field data as well as plasma data has revealed numerous issues and problems with the available, processed, datasets, that we are still working to solve. We anticipate this comprehensive single archive of all Helios in-situ data, beyond its inherent scientific value, will also be an invaluable asset to the both the Solar Probe Plus and Solar Orbiter missions.

Displacement Theories for In-Flight Deformed Shape Predictions of Aerospace Structures

NASA Technical Reports Server (NTRS)

Ko, William L.; Richards, W. L.; Tran, Van t.

2007-01-01

Displacement theories are developed for a variety of structures with the goal of providing real-time shape predictions for aerospace vehicles during flight. These theories are initially developed for a cantilever beam to predict the deformed shapes of the Helios flying wing. The main structural configuration of the Helios wing is a cantilever wing tubular spar subjected to bending, torsion, and combined bending and torsion loading. The displacement equations that are formulated are expressed in terms of strains measured at multiple sensing stations equally spaced on the surface of the wing spar. Displacement theories for other structures, such as tapered cantilever beams, two-point supported beams, wing boxes, and plates also are developed. The accuracy of the displacement theories is successfully validated by finite-element analysis and classical beam theory using input-strains generated by finite-element analysis. The displacement equations and associated strain-sensing system (such as fiber optic sensors) create a powerful means for in-flight deformation monitoring of aerospace structures. This method serves multiple purposes for structural shape sensing, loads monitoring, and structural health monitoring. Ultimately, the calculated displacement data can be visually displayed to the ground-based pilot or used as input to the control system to actively control the shape of structures during flight.

Solar-wind predictions for the Parker Solar Probe orbit. Near-Sun extrapolations derived from an empirical solar-wind model based on Helios and OMNI observations

NASA Astrophysics Data System (ADS)

Venzmer, M. S.; Bothmer, V.

2018-03-01

Context. The Parker Solar Probe (PSP; formerly Solar Probe Plus) mission will be humanitys first in situ exploration of the solar corona with closest perihelia at 9.86 solar radii (R⊙) distance to the Sun. It will help answer hitherto unresolved questions on the heating of the solar corona and the source and acceleration of the solar wind and solar energetic particles. The scope of this study is to model the solar-wind environment for PSPs unprecedented distances in its prime mission phase during the years 2018 to 2025. The study is performed within the Coronagraphic German And US SolarProbePlus Survey (CGAUSS) which is the German contribution to the PSP mission as part of the Wide-field Imager for Solar PRobe. Aim. We present an empirical solar-wind model for the inner heliosphere which is derived from OMNI and Helios data. The German-US space probes Helios 1 and Helios 2 flew in the 1970s and observed solar wind in the ecliptic within heliocentric distances of 0.29 au to 0.98 au. The OMNI database consists of multi-spacecraft intercalibrated in situ data obtained near 1 au over more than five solar cycles. The international sunspot number (SSN) and its predictions are used to derive dependencies of the major solar-wind parameters on solar activity and to forecast their properties for the PSP mission. Methods: The frequency distributions for the solar-wind key parameters, magnetic field strength, proton velocity, density, and temperature, are represented by lognormal functions. In addition, we consider the velocity distributions bi-componental shape, consisting of a slower and a faster part. Functional relations to solar activity are compiled with use of the OMNI data by correlating and fitting the frequency distributions with the SSN. Further, based on the combined data set from both Helios probes, the parameters frequency distributions are fitted with respect to solar distance to obtain power law dependencies. Thus an empirical solar-wind model for the inner heliosphere confined to the ecliptic region is derived, accounting for solar activity and for solar distance through adequate shifts of the lognormal distributions. Finally, the inclusion of SSN predictions and the extrapolation down to PSPs perihelion region enables us to estimate the solar-wind environment for PSPs planned trajectory during its mission duration. Results: The CGAUSS empirical solar-wind model for PSP yields dependencies on solar activity and solar distance for the solar-wind parameters' frequency distributions. The estimated solar-wind median values for PSPs first perihelion in 2018 at a solar distance of 0.16 au are 87 nT, 340 km s-1, 214 cm-3, and 503 000 K. The estimates for PSPs first closest perihelion, occurring in 2024 at 0.046 au (9.86 R⊙), are 943 nT, 290 km s-1, 2951 cm-3, and 1 930 000 K. Since the modeled velocity and temperature values below approximately 20 R⊙appear overestimated in comparison with existing observations, this suggests that PSP will directly measure solar-wind acceleration and heating processes below 20 R⊙ as planned.

Modeling the Solar Dust Environment at 9.5 Solar Radii: Revealing Radiance Trends with MESSENGER Star Tracker Data

NASA Astrophysics Data System (ADS)

Strong, S. B.; Strikwerda, T.; Lario, D.; Raouafi, N.; Decker, R.

2010-12-01

The main components of interplanetary dust are created through destruction, erosion, and collision of asteroids and comets (e.g. Mann et al. 2006). Solar radiation forces distribute these interplanetary dust particles throughout the solar system. The percent contribution of these source particulates to the net interplanetary dust distribution can reveal information about solar nebula conditions, within which these objects are formed. In the absence of observational data (e.g. Helios, Pioneer), specifically at distances less than 0.3 AU, the precise dust distributions remain unknown and limited to 1 AU extrapolative models (e.g. Mann et al. 2003). We have developed a model suitable for the investigation of scattered dust and electron irradiance incident on a sensor for distances inward of 1 AU. The model utilizes the Grün et al. (1985) and Mann et al. (2004) dust distribution theory combined with Mie theory and Thomson electron scattering to determine the magnitude of solar irradiance scattered towards an optical sensor as a function of helio-ecliptic latitude and longitude. MESSENGER star tracker observations (launch to 2010) of the ambient celestial background combined with Helios data (Lienert et al. 1982) reveal trends in support of the model predictions. This analysis further emphasizes the need to characterize the inner solar system dust environment in anticipation of near-Solar missions.

Cost-Effective Additive Manufacturing in Space: HELIOS Technology Challenge Guide

NASA Technical Reports Server (NTRS)

DeVieneni, Alayna; Velez, Carlos Andres; Benjamin, David; Hollenbeck, Jay

2012-01-01

Welcome to the HELIOS Technology Challenge Guide. This document is intended to serve as a general road map for participants of the HELIOS Technology Challenge [HTC] Program and the associated inaugural challenge: HTC-01: Cost-Effective Additive Manufacturing in Space. Please note that this guide is not a rule book and is not meant to hinder the development of innovative ideas. Its primary goal is to highlight the objectives of the HTC-01 Challenge and to describe possible solution routes and pitfalls that such technology may encounter in space. Please also note that participants wishing to demonstrate any hardware developed under this program during any future HELIOS Technology Challenge showcase event(s) may be subject to event regulations to be published separately at a later date.

Advanced Test Reactor Core Modeling Update Project Annual Report for Fiscal Year 2012

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

David W. Nigg, Principal Investigator; Kevin A. Steuhm, Project Manager

Legacy computational reactor physics software tools and protocols currently used for support of Advanced Test Reactor (ATR) core fuel management and safety assurance, and to some extent, experiment management, are inconsistent with the state of modern nuclear engineering practice, and are difficult, if not impossible, to properly verify and validate (V&V) according to modern standards. Furthermore, the legacy staff knowledge required for application of these tools and protocols from the 1960s and 1970s is rapidly being lost due to staff turnover and retirements. In late 2009, the Idaho National Laboratory (INL) initiated a focused effort, the ATR Core Modeling Updatemore » Project, to address this situation through the introduction of modern high-fidelity computational software and protocols. This aggressive computational and experimental campaign will have a broad strategic impact on the operation of the ATR, both in terms of improved computational efficiency and accuracy for support of ongoing DOE programs as well as in terms of national and international recognition of the ATR National Scientific User Facility (NSUF). The ATR Core Modeling Update Project, targeted for full implementation in phase with the next anticipated ATR Core Internals Changeout (CIC) in the 2014-2015 time frame, began during the last quarter of Fiscal Year 2009, and has just completed its third full year. Key accomplishments so far have encompassed both computational as well as experimental work. A new suite of stochastic and deterministic transport theory based reactor physics codes and their supporting nuclear data libraries (HELIOS, KENO6/SCALE, NEWT/SCALE, ATTILA, and an extended implementation of MCNP5) has been installed at the INL under various licensing arrangements. Corresponding models of the ATR and ATRC are now operational with all five codes, demonstrating the basic feasibility of the new code packages for their intended purpose. Of particular importance, a set of as-run core depletion HELIOS calculations for all ATR cycles since August 2009, Cycle 145A through Cycle 151B, was successfully completed during 2012. This major effort supported a decision late in the year to proceed with the phased incorporation of the HELIOS methodology into the ATR Core Safety Analysis Package (CSAP) preparation process, in parallel with the established PDQ-based methodology, beginning late in Fiscal Year 2012. Acquisition of the advanced SERPENT (VTT-Finland) and MC21 (DOE-NR) Monte Carlo stochastic neutronics simulation codes was also initiated during the year and some initial applications of SERPENT to ATRC experiment analysis were demonstrated. These two new codes will offer significant additional capability, including the possibility of full-3D Monte Carlo fuel management support capabilities for the ATR at some point in the future. Finally, a capability for rigorous sensitivity analysis and uncertainty quantification based on the TSUNAMI system has been implemented and initial computational results have been obtained. This capability will have many applications as a tool for understanding the margins of uncertainty in the new models as well as for validation experiment design and interpretation.« less

IFNy+ and IFNy- Treg subsets with stable and unstable Foxp3 expression in kidney transplant recipients with good long-term graft function.

PubMed

Trojan, Karina; Unterrainer, Christian; Aly, Mostafa; Zhu, Li; Weimer, Rolf; Bulut, Nuray; Morath, Christian; Opelz, Gerhard; Daniel, Volker

2016-10-29

Treg are a heterogenous cell population. In the present study we attempted to identify Treg subsets that might contribute to stable and good long-term graft function. Lymphocyte and Treg subsets were studied in 136 kidney transplant recipients with good long-term graft function and in 52 healthy control individuals using eight-color-fluorescence flow cytometry. Foxp3 TSDR methylation status was investigated in enriched IFNy+ and IFNy- Treg preparations using high resolution melt analysis. Compared with healthy controls, patients showed strong associations of IFNy secreting Helios+ and Helios- Treg with Treg that co-expressed perforin and/or CTLA4 (CD152; p<0.01). Moreover they showed associations of IFNy-Helios+ Treg with Treg that produced TGFβ and/or perforin and of IFNy-Helios- Treg with TGFβ production (all p<0.01). Only in patients, but not in healthy controls, were IFNy- Helios+ and Helios- Treg associated with higher CD45+, CD3+, (CD4+), CD19+ lymphocyte counts (p<0.001). In addition IFNy-Helios+ Treg were associated with CD16+56+ lymphocytes (p<0.001). Enriched IFNy- Treg from female but not male patients showed an association of Foxp3 methylation with higher total Treg and higher Helios+IFNy-, CXCR3+Lselectin+ (CD183+CD62L+), CXCR3-Lselectin+ and CD28+HLADR+ Treg subsets (p<0.01). Enriched IFNy+ Treg from male patients showed an association of demethylated Foxp3 with total Treg and IL10-TFGβ+ Treg counts, and in enriched IFNy- Treg an association of methylated Foxp3 with APO1/FasR+FasL+ (CD95+CD178+) Treg (p<0.01). Kidney recipients with good long-term graft function possess IFNy+ and IFNy- Treg with stable and unstable Foxp3 expression in the blood. They co-express CD28, HLADR, CTLA4, CXCR3, Lselectin, TGFβ, perforin and FasL and might contribute to the establishment and maintenance of good long-term graft function. Copyright © 2016. Published by Elsevier B.V.

NASA's Helios Prototype aircraft taking off from the Pacific Missile Range Facility, Kauai, Hawaii,

NASA Technical Reports Server (NTRS)

2001-01-01

As a follow-on to the Centurion (and earlier Pathfinder and Pathfinder-Plus) aircraft, the solar-powered Helios Prototype is the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions in the stratosphere. Developed by AeroVironment, Inc., of Monrovia, California, under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the unique craft is intended to demonstrate two key missions: the ability to reach and sustain horizontal flight at 100,000 feet altitude on a single-day flight in 2001, and to maintain flight above 50,000 feet altitude for at least four days in 2003, with the aid of a regenerative fuel cell-based energy storage system now in development. Both of these missions will be powered by electricity derived from non-polluting solar energy. The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at NASA's Dryden Flight Research Center in late 1998. The craft has a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of its solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. The remotely piloted, electrically powered Helios Prototype went aloft on its maiden low-altitude checkout flight Sept. 8, 1999, over Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center in the Southern California desert. The initial flight series was flown on battery power as a risk-reduction measure. In all, six flights were flown in the Helios Protoype's initial development series. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved aerodynamic efficiency, allowing the Helios Prototype to fly higher, longer and with a larger payload than the smaller craft. In addition, project engineers added a differential Global Positioning Satellite (GPS) system to improve navigation, an extensive turbulence monitoring system payload to record structural loads on the aircraft both in the air and on the ground, and radiator plates to assist in cooling the avionics at high altitudes where there is little air to dissipate heat. During 2000, more than 65,000 solar cells in 1,800 groups were mounted on the upper surface of Helios' wing. Produced by SunPower, Inc., these bi-facial silicon cells are about 19 percent efficient in the flight regime in which the helios is designed to operate, converting about 19 percent of the solar energy they receive into electrical current. The entire array is capable of producing a maximum output of about 35 kw at high noon on a summer day. The mission to reach and sustain flight at 100,000 feet in 2001 requires use of all 14 motors and minimal ballast to save weight, with the aircraft weighing in at only a little more than 1,600 lbs. The four-day mission above 50,000 feet envisioned for the Helios Prototype in 2003will see only eight motors powering the craft and the addition of the regenerative energy storage system now in development. The system will increase the Helios Prototype's flight weight to a little over 2,000 lbs. Fewer motors are needed for the long-endurance mission due to the lesser altitude requirements, and the excess electrical energy generated by the solar arrays during the daytime will be diverted to the hydrogen-oxygen fuel cell energy storage system, which will release the electricity to power the Helios after dark. With other system reliability improvements, production versions of the Helios are expected to fly missions lasting months at a time, becoming true 'atmospheric satellites.'

The Helios Prototype aircraft during initial climb-out to the west over the Pacific Ocean.

NASA Technical Reports Server (NTRS)

2001-01-01

As a follow-on to the Centurion (and earlier Pathfinder and Pathfinder-Plus) aircraft, the solar-powered Helios Prototype is the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions in the stratosphere. Developed by AeroVironment, Inc., of Monrovia, California, under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the unique craft is intended to demonstrate two key missions: the ability to reach and sustain horizontal flight at 100,000 feet altitude on a single-day flight in 2001, and to maintain flight above 50,000 feet altitude for at least four days in 2003, with the aid of a regenerative fuel cell-based energy storage system now in development. Both of these missions will be powered by electricity derived from non-polluting solar energy. The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at NASA's Dryden Flight Research Center in late 1998. The craft has a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of its solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. The remotely piloted, electrically powered Helios Prototype went aloft on its maiden low-altitude checkout flight Sept. 8, 1999, over Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center in the Southern California desert. The initial flight series was flown on battery power as a risk-reduction measure. In all, six flights were flown in the Helios Protoype's initial development series. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved aerodynamic efficiency, allowing the Helios Prototype to fly higher, longer and with a larger payload than the smaller craft. In addition, project engineers added a differential Global Positioning Satellite (GPS) system to improve navigation, an extensive turbulence monitoring system payload to record structural loads on the aircraft both in the air and on the ground, and radiator plates to assist in cooling the avionics at high altitudes where there is little air to dissipate heat. During 2000, more than 65,000 solar cells in 1,800 groups were mounted on the upper surface of Helios' wing. Produced by SunPower, Inc., these bi-facial silicon cells are about 19 percent efficient in the flight regime in which the helios is designed to operate, converting about 19 percent of the solar energy they receive into electrical current. The entire array is capable of producing a maximum output of about 35 kw at high noon on a summer day. The mission to reach and sustain flight at 100,000 feet in 2001 requires use of all 14 motors and minimal ballast to save weight, with the aircraft weighing in at only a little more than 1,600 lbs. The four-day mission above 50,000 feet envisioned for the Helios Prototype in 2003will see only eight motors powering the craft and the addition of the regenerative energy storage system now in development. The system will increase the Helios Prototype's flight weight to a little over 2,000 lbs. Fewer motors are needed for the long-endurance mission due to the lesser altitude requirements, and the excess electrical energy generated by the solar arrays during the daytime will be diverted to the hydrogen-oxygen fuel cell energy storage system, which will release the electricity to power the Helios after dark. With other system reliability improvements, production versions of the Helios are expected to fly missions lasting months at a time, becoming true 'atmospheric satellites.'

The Helios Prototype aircraft in a northerly climb over Niihau Island, Hawaii, at about 8,000 feet a

NASA Technical Reports Server (NTRS)

2001-01-01

As a follow-on to the Centurion (and earlier Pathfinder and Pathfinder-Plus) aircraft, the solar-powered Helios Prototype is the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions in the stratosphere. Developed by AeroVironment, Inc., of Monrovia, California, under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the unique craft is intended to demonstrate two key missions: the ability to reach and sustain horizontal flight at 100,000 feet altitude on a single-day flight in 2001, and to maintain flight above 50,000 feet altitude for at least four days in 2003, with the aid of a regenerative fuel cell-based energy storage system now in development. Both of these missions will be powered by electricity derived from non-polluting solar energy. The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at NASA's Dryden Flight Research Center in late 1998. The craft has a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of its solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. The remotely piloted, electrically powered Helios Prototype went aloft on its maiden low-altitude checkout flight Sept. 8, 1999, over Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center in the Southern California desert. The initial flight series was flown on battery power as a risk-reduction measure. In all, six flights were flown in the Helios Protoype's initial development series. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved aerodynamic efficiency, allowing the Helios Prototype to fly higher, longer and with a larger payload than the smaller craft. In addition, project engineers added a differential Global Positioning Satellite (GPS) system to improve navigation, an extensive turbulence monitoring system payload to record structural loads on the aircraft both in the air and on the ground, and radiator plates to assist in cooling the avionics at high altitudes where there is little air to dissipate heat. During 2000, more than 65,000 solar cells in 1,800 groups were mounted on the upper surface of Helios' wing. Produced by SunPower, Inc., these bi-facial silicon cells are about 19 percent efficient in the flight regime in which the helios is designed to operate, converting about 19 percent of the solar energy they receive into electrical current. The entire array is capable of producing a maximum output of about 35 kw at high noon on a summer day. The mission to reach and sustain flight at 100,000 feet in 2001 requires use of all 14 motors and minimal ballast to save weight, with the aircraft weighing in at only a little more than 1,600 lbs. The four-day mission above 50,000 feet envisioned for the Helios Prototype in 2003will see only eight motors powering the craft and the addition of the regenerative energy storage system now in development. The system will increase the Helios Prototype's flight weight to a little over 2,000 lbs. Fewer motors are needed for the long-endurance mission due to the lesser altitude requirements, and the excess electrical energy generated by the solar arrays during the daytime will be diverted to the hydrogen-oxygen fuel cell energy storage system, which will release the electricity to power the Helios after dark. With other system reliability improvements, production versions of the Helios are expected to fly missions lasting months at a time, becoming true 'atmospheric satellites.'

Dissolved oxygen control and monitoring implementation in the liquid lead bismuth eutectic loop: HELIOS

NASA Astrophysics Data System (ADS)

Nam, Hyo On; Lim, Jun; Han, Dong Yoon; Hwang, Il Soon

2008-06-01

A 12 m tall LBE coolant loop, named as HELIOS, has been developed by thermal-hydraulic scaling of the PEACER-300MWe. Thermo-hydraulic experiment and materials test are the principal purposes of HELIOS operation. In this study, an yttria stabilized zirconia (YSZ) based oxygen sensor that was hermetically sealed for long-term applications using the electromagnetically swaged metal-ceramic joining method, have been developed for high temperature oxygen control application over a long period of time. The rugged electrode design has been calibrated to absolute metal-oxide equilibrium by using a first principle of detecting pure metal-oxide transition using electrochemical impedance spectroscopy (EIS). During the materials tests in HELIOS, dissolved oxygen concentration was administered at the intended condition of 10 -6 wt% by direct gas bubbling with Ar + 4%H 2, Ar + 5%O 2 and/or pure Ar while corrosion tests were conducted for up to 1000 h with inspection after each 333 h. During the total 1000 h corrosion test, oxygen concentration was measured by oxygen sensor. The result confirmed that the direct gas bubbling method is a viable and practical option for controlling oxygen concentration in large loops including HELIOS.

The Philosophy of User Interfaces in HELIO and the Importance of CASSIS

NASA Astrophysics Data System (ADS)

Bonnin, X.; Aboudarham, J.; Renié, C.; Csillaghy, A.; Messerotti, M.; Bentley, R. D.

2012-09-01

HELIO is a European project funded under FP7 (Project No. 238969). One of its goals as a Heliospheric Virtual Observatory is to provide an easy access to many datasets scattered all over the world, in the fields of Solar physics, Heliophysics, and Planetary magnetospheres. The efficiency of such a tool is very much related to the quality of the user interface. HELIO infrastructure is based on a Service Oriented Architecture (SOA), regrouping a network of standalone components, which allows four main types of interfaces: - HELIO Front End (HFE) is a browser-based user interface, which offers a centralized access to the HELIO main functionalities. Especially, it provides the possibility to reach data directly, or to refine selection by determination of observing characteristics, such as which instrument was observing at that time, which instrument was at this location, etc. - Many services/components provide their own standalone graphical user interface. While one can directly access individually each of these interfaces, they can also be connected together. - Most services also provide direct access for any tools through a public interface. A small java library, called Java API, simplifies this access by providing client stubs for services and shields the user from security, discovery and failover issues. - Workflows capabilities are available in HELIO, allowing complex combination of queries over several services. We want the user to be able to navigate easily, at his needs, through the various interfaces, and possibly use a specific one in order to make much-dedicated queries. We will also emphasize the importance of the CASSIS project (Coordination Action for the integration of Solar System Infrastructure and Science) in encouraging the interoperability necessary to undertake scientific studies that span disciplinary boundaries. If related projects follow the guidelines being developed by CASSIS then using external resources with HELIO will be greatly simplified.

Project Helios-A. [mission planning for solar probe

NASA Technical Reports Server (NTRS)

1974-01-01

The Helios-A solar probe which will fly within 28 million miles of the sun is described as a joint American and German project. The spacecraft and instrument designs, planned experiments, and mission are briefly discussed.

Helios: a tangible and augmented environment to learn optical phenomena in astronomy

NASA Astrophysics Data System (ADS)

Fleck, Stéphanie; Hachet, Martin

2015-10-01

France is among the few countries that have integrated astronomy in primary school levels. However, for fifteen years, a lot of studies have shown that children have difficulties in understanding elementary astronomic phenomena such as day/night alternation, seasons or moon phases' evolution. To understand these phenomena, learners have to mentally construct 3D perceptions of aster motions and to understand how light propagates from an allocentric point of view. Therefore, 4-5 grades children (8 to 11 years old), who are developing their spatial cognition, have many difficulties to assimilate geometric optical problems that are linked to astronomy. To make astronomical learning more efficient for young pupils, we have designed an Augmented Inquiry-Based Learning Environment (AIBLE): HELIOS. Because manipulations in astronomy are intrinsically not possible, we propose to manipulate the underlying model. With HELIOS, virtual replicas of the Sun, Moon and Earth are directly manipulated from tangible manipulations. This digital support combines the possibilities of Augmented Reality (AR) while maintaining intuitive interactions following the principles of didactic of sciences. Light properties are taken into account and shadows of Earth and Moon are directly produced by an omnidirectional light source associated to the virtual Sun. This AR environment provides users with experiences they would otherwise not be able to experiment in the physical world. Our main goal is that students can take active control of their learning, express and support their ideas, make predictions and hypotheses, and test them by conducting investigations.

The Heliophysics Integrated Observatory

NASA Astrophysics Data System (ADS)

Csillaghy, A.; Bentley, R. D.

2009-12-01

HELIO is a new Europe-wide, FP7-funded distributed network of services that will address the needs of a broad community of researchers in heliophysics. This new research field explores the “Sun-Solar System Connection” and requires the joint exploitation of solar, heliospheric, magnetospheric and ionospheric observations. HELIO will provide the most comprehensive integrated information system in this domain; it will coordinate access to the distributed resources needed by the community, and will provide access to services to mine and analyse the data. HELIO will be designed as a Service-oriented Architecture. The initial infrastructure will include services based on metadata and data servers deployed by the European Grid of Solar Observations (EGSO). We will extend these to address observations from all the disciplines of heliophysics; differences in the way the domains describe and handle the data will be resolved using semantic mapping techniques. Processing and storage services will allow the user to explore the data and create the products that meet stringent standards of interoperability. These capabilities will be orchestrated with the data and metadata services using the Taverna workflow tool. HELIO will address the challenges along the FP7 I3 activities model: (1) Networking: we will cooperate closely with the community to define new standards for heliophysics and the required capabilities of the HELIO system. (2) Services: we will integrate the services developed by the project and other groups to produce an infrastructure that can easily be extended to satisfy the growing and changing needs of the community. (3) Joint Research: we will develop search tools that span disciplinary boundaries and explore new types of user-friendly interfaces HELIO will be a key component of a worldwide effort to integrate heliophysics data and will coordinate closely with international organizations to exploit synergies with complementary domains.

Combining FoxP3 and Helios with GARP/LAP markers can identify expanded Treg subsets in cancer patients.

PubMed

Abd Al Samid, May; Chaudhary, Belal; Khaled, Yazan S; Ammori, Basil J; Elkord, Eyad

2016-03-22

Regulatory T cells (Tregs) comprise numerous heterogeneous subsets with distinct phenotypic and functional features. Identifying Treg markers is critical to investigate the role and clinical impact of various Treg subsets in pathological settings, and also for developing more effective immunotherapies. We have recently shown that non-activated FoxP3-Helios+ and activated FoxP3+/-Helios+ CD4+ T cells express GARP/LAP immunosuppressive markers in healthy donors. In this study we report similar observations in the peripheral blood of patients with pancreatic cancer (PC) and liver metastases from colorectal cancer (LICRC). Comparing levels of different Treg subpopulations in cancer patients and controls, we report that in PC patients, and unlike LICRC patients, there was no increase in Treg levels as defined by FoxP3 and Helios. However, defining Tregs based on GARP/LAP expression showed that FoxP3-LAP+ Tregs in non-activated and activated settings, and FoxP3+Helios+GARP+LAP+ activated Tregs were significantly increased in both groups of patients, compared with controls. This work implies that a combination of Treg-specific markers could be used to more accurately determine expanded Treg subsets and to understand their contribution in cancer settings. Additionally, GARP-/+LAP+ CD4+ T cells made IL-10, and not IFN-γ, and levels of IL-10-secreting CD4+ T cells were elevated in LICRC patients, especially with higher tumor staging. Taken together, our results indicate that investigations of Treg levels in different cancers should consider diverse Treg-related markers such as GARP, LAP, Helios, and others and not only FoxP3 as a sole Treg-specific marker.

Technique Using Axicons For Generating Flat Top Laser Beam Profiles

NASA Astrophysics Data System (ADS)

Viswanathan, V. K.; Woodfin, G. L.; Stahl, D.; Carpenter, J. P.; Kyrala, G.

1983-11-01

In certain fusion experiments using CO2 lasers, like Helios, it is desired to produce a focal spot several times larger than the nominal focal spot, with a flat beam profile. The typical focal spot in Helios is roughly 70 μm and just defocussing the beam produces beam breakup, with several hot spots with roughly the original diameter, and a gaussian distribution. A number of schemes were tried to achieve a large spot with desired characteristics. These are described in the article. Axicons were found to produce spots with desired characteristics. Axicons are lenses or mirrors having a cone-shaped surface. The various schemes are described, as well as an. experiment in Helios which confirmed that axicons produced the spots with desirable characteristics. Helios is an 8-beam CO2 laser which produces 10 kJ at power in excess of 20 TW. It is currently being used for Laser Fusion studies at the Los Alamos National Laboratory.

Synoptic maps for the heliospheric Thomson scattering brightness as observed by the Helios photometers

NASA Technical Reports Server (NTRS)

Hick, P.; Jackson, B. V.; Schwenn, R.

1991-01-01

A method for displaying the electron Thomson scattering intensity in the inner heliosphere as observed by the zodiacal light photometers on board the Helios spacecraft in the form of synoptic maps is presented. The method is based on the assumption that the bulk of the scattering electrons along the line of sight is located near the point closest to the sun. Inner-heliospheric structures will generally be represented properly in these synoptic maps only if they are sufficiently long-lived (that is, a significant fraction of a solar rotation period). The examples of Helios synoptic maps discussed (from data in April 1976 and November 1978), indicate that it is possible to identify large-scale, long-lived density enhancements in the inner heliosphere. It is expected that the Helios synoptic maps will be particularly useful in the study of corotating structures (e.g., streamers), and the maps will be most reliable during periods when few transient featurs are present in the corona, i.e., during solar minimum.

Solar radiation pressure effects on the Helios spacecraft

NASA Technical Reports Server (NTRS)

Georgevic, R. M.

1976-01-01

A mathematical model of the solar radiation force and torques, developed for the Mariner 10 Venus/Mercury spacecraft mission, was used for a detailed analysis of the effects of solar light pressure on the Helios spacecraft. Due to the fact that the main body of the Helios spacecraft is a surface of enclosure, inside of which most of the reradiated thermal energy is lost, expressions for the portion of the solar radiation force, produced by the thermal reradiation, had to be given a different form. Hence the need for the derivation of a somewhat different theoretical model for the force acting on the main body of the spacecraft.

Helios High Altitude Long Endurance Mission Mishap

NASA Technical Reports Server (NTRS)

Henwood, Barton E.

2009-01-01

This slide presentation reviews the failure of the Helios solar aircraft failure. Included are pictures of the aircraft, inflight, and after the mishap, analysis of the root causes of the mishap, contributing factors, recommendations and lessons learned in respect to crew training, and assessing the level of risk.

Preliminary analysis of coronal electron content measurements from spacecraft Helios A around first solar occultation

NASA Technical Reports Server (NTRS)

Edenhofer, P.; Esposito, P. B.; Martin, W. L.; Zygielbaum, A. I.; Hansen, R. T.; Hansen, S. F.; Lueneburg, E.

1977-01-01

Steady-state and dynamical features of the electron density distribution in the solar corona emerge from a preliminary analysis of Helios A electron content measurements. There are strong indications that correlations can be established with earth-bound K-coronagraph measurements.

Development of a New 47-Group Library for the CASL Neutronics Simulators

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

Kim, Kang Seog; Williams, Mark L; Wiarda, Dorothea

The CASL core simulator MPACT is under development for the neutronics and thermal-hydraulics coupled simulation for the pressurized light water reactors. The key characteristics of the MPACT code include a subgroup method for resonance self-shielding, and a whole core solver with a 1D/2D synthesis method. The ORNL AMPX/SCALE code packages have been significantly improved to support various intermediate resonance self-shielding approximations such as the subgroup and embedded self-shielding methods. New 47-group AMPX and MPACT libraries based on ENDF/B-VII.0 have been generated for the CASL core simulator MPACT of which group structure comes from the HELIOS library. The new 47-group MPACTmore » library includes all nuclear data required for static and transient core simulations. This study discusses a detailed procedure to generate the 47-group AMPX and MPACT libraries and benchmark results for the VERA progression problems.« less

Process for Refining and Validating a Finite Element Model of an Experimental High-Altitude, Long-Endurance (HALE) Aircraft

DTIC Science & Technology

2011-06-01

7 Figure 4. Helios flying near the Hawaiian islands of Niihau and Lehua [15] ................... 8 Figure 5. Plan view of ERAST Program aircraft...Figure 4. Helios flying near the Hawaiian islands of Niihau and Lehua [15] 9 Figure 5. Plan view of ERAST Program aircraft

Comparison of CME masses and kinetic energies near the Sun and in the inner heliosphere

NASA Technical Reports Server (NTRS)

Webb, D. F.; Howard, R. A.; Jackson, B. V.

1995-01-01

Masses have now been determined for many of the CMEs observed in the inner heliosphere by the HELIOS 1 and 2 zodiacal light photometers. The speed of the brightest material of each CME has also been measured so that, for events having both mass and speed determinations, the kinetic energies of the CMEs are estimated. We compare the masses and kinetic energies of the individual CMEs measured in the inner heliosphere by HELIOS and near the Sun from observations by the SOLWIND (1979-1983) and SMM coronagraphs (1980). Where feasible we also compare the speeds of the same CMEs. We find that the HELIOS masses and energies tend to be somewhat larger by factors of 2-5 than those derived from the coronagraph data. We also compare the distribution of the masses and energies of the HELIOS and coronagraph CMEs over the solar cycle. These results provide an important baseline for observations of CMEs from coronagraphs, from the ISEE-3/ICE, WIND and Ulysses spacecraft and in the future from SOHO.

Synoptic maps of heliospheric Thomson scattering brightness from 1974-1985 as observed by the Helios photometers

NASA Technical Reports Server (NTRS)

Hick, P.; Jackson, B. V.; Schwenn, R.

1992-01-01

We display the electron Thomson scattering intensity of the inner heliosphere as observed by the zodiacal light photometers on board the Helios spacecraft in the form of synoptic maps. The technique extrapolates the brightness information from each photometer sector near the Sun and constructs a latitude/longitude map at a given solar height. These data are unique in that they give a determination of heliospheric structures out of the ecliptic above the primary region of solar wind acceleration. The spatial extent of bright, co-rotating heliospheric structures is readily observed in the data north and south of the ecliptic plane where the Helios photometer coverage is most complete. Because the technique has been used on the complete Helios data set from 1974 to 1985, we observe the change in our synoptic maps with solar cycle. Bright structures are concentrated near the heliospheric equator at solar minimum, while at solar maximum bright structures are found at far higher heliographic latitudes. A comparison of these maps with other forms of synoptic data are shown for two available intervals.

ED01-0230-1

NASA Image and Video Library

2001-08-13

NASA's Helios Prototype aircraft taking off from the Pacific Missile Range Facility, Kauai, Hawaii, for the record flight. As a follow-on to the Centurion (and earlier Pathfinder and Pathfinder-Plus) aircraft, the solar-powered Helios Prototype is the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions in the stratosphere. Developed by AeroVironment, Inc., of Monrovia, California, under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the unique craft is intended to demonstrate two key missions: the ability to reach and sustain horizontal flight at 100,000 feet altitude on a single-day flight in 2001, and to maintain flight above 50,000 feet altitude for at least four days in 2003, with the aid of a regenerative fuel cell-based energy storage system now in development. Both of these missions will be powered by electricity derived from non-polluting solar energy. The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at NASA's Dryden Flight Research Center in late 1998. The craft has a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of its solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. The remotely piloted, electrically powered Helios Prototype went aloft on its maiden low-altitude checkout flight Sept. 8, 1999, over Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center in the Southern California desert. The initial flight series was flown on battery power as a risk-reduction measure. In all, six flights were flown in the Helios Protoype's initial development series. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingsp

Evolución de estrellas enanas blancas de Helio de masa baja e intermedia

NASA Astrophysics Data System (ADS)

Althaus, L. G.; Benvenuto, O. G.

Numerosas observaciones realizadas particularmente en los últimos dos años parecen confirmar que las enanas blancas (EB) de helio de masa baja e intermedia son el resultado de la evolución de sistemas binarios cercanos. Con el objeto de realizar una adecuada interpretación de estos objetos son necesarios modelos de EBs de helio lo más detallado posibles. En este estudio presentamos cálculos detallados de la evolución de EBs de helio con masas entre M=0.1Msolar y M=0.5Msolar a intervalos de 0.05Msolar . Para ello, hemos tenido en cuenta los efectos de temperatura finita mediante un código de evolución estelar lo más actualizado posible. En particular, el transporte de energía es descripto en el marco del nuevo modelo para la convección turbulenta desarrollado por Canuto - Mazzitelli. Además hemos considerado la nueva ecuación de estado para plasmas de helio de Saumon et al. y nuevas opacidades radiativas OPAL. Las pérdidas por neutrinos fueron asimismo tenidas en cuenta. Excepto para las EBs más masivas, nuestros modelos iniciales están ubicados en las cercanías de la correspondiente línea de Hayashi para configuraciones de helio. Nuestros resultados muestran que existe una región prohibida en el diagrama observacional HR donde ninguna EB de helio puede encontrarse. Dicha región es para log{(L/Lsolar )}>= -0.25 and log{Teff} >= 4.45. Hemos encontrado también que los tracks evolutivos en el diagrama HR en el dominio de alta luminosidad (pre - EB) son fuertemente afectados por la eficiencia convectiva y que las pérdidas por neutrinos son importantes en los modelos más masivos. Finalmente hemos analizado la estructura de la zona convectiva externa encontrando que la teoría de Canuto - Mazzitelli conduce a un perfil convectivo muy diferente del dado por cualquier versión de la popular teoría de la mixing length. Si bién este comportamiento es decisivo en el contexto de las inestabilides pulsacionales, los radios y gravedades superficiales de los modelos no son afectados al incluir la nueva teoría de convección.

Modelling of the Gadolinium Fuel Test IFA-681 using the BISON Code

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

Pastore, Giovanni; Hales, Jason Dean; Novascone, Stephen Rhead

2016-05-01

In this work, application of Idaho National Laboratory’s fuel performance code BISON to modelling of fuel rods from the Halden IFA-681 gadolinium fuel test is presented. First, an overview is given of BISON models, focusing on UO2/UO2-Gd2O3 fuel and Zircaloy cladding. Then, BISON analyses of selected fuel rods from the IFA-681 test are performed. For the first time in a BISON application to integral fuel rod simulations, the analysis is informed by detailed neutronics calculations in order to accurately capture the radial power profile throughout the fuel, which is strongly affected by the complex evolution of absorber Gd isotopes. Inmore » particular, radial power profiles calculated at IFE–Halden Reactor Project with the HELIOS code are used. The work has been carried out in the frame of the collaboration between Idaho National Laboratory and Halden Reactor Project. Some slide have been added as an Appendix to present the newly developed PolyPole-1 algorithm for modeling of intra-granular fission gas release.« less

HELIO: The Heliophysics Integrated Observatory

NASA Technical Reports Server (NTRS)

Bentley, R. D.; Csillaghy, A.; Aboudarham, J.; Jacquey, C.; Hapgood, M. A.; Bocchialini, K.; Messerotti, M.; Brooke, J.; Gallagher, P.; Fox, P.;

Field-design optimization with triangular heliostat pods

NASA Astrophysics Data System (ADS)

Domínguez-Bravo, Carmen-Ana; Bode, Sebastian-James; Heiming, Gregor; Richter, Pascal; Carrizosa, Emilio; Fernández-Cara, Enrique; Frank, Martin; Gauché, Paul

2016-05-01

In this paper the optimization of a heliostat field with triangular heliostat pods is addressed. The use of structures which allow the combination of several heliostats into a common pod system aims to reduce the high costs associated with the heliostat field and therefore reduces the Levelized Cost of Electricity value. A pattern-based algorithm and two pattern-free algorithms are adapted to handle the field layout problem with triangular heliostat pods. Under the Helio100 project in South Africa, a new small-scale Solar Power Tower plant has been recently constructed. The Helio100 plant has 20 triangular pods (each with 6 heliostats) whose positions follow a linear pattern. The obtained field layouts after optimization are compared against the reference field Helio100.

Helios-1 Faraday rotation experiment - Results and interpretations of the solar occultations in 1975

NASA Technical Reports Server (NTRS)

Volland, H.; Bird, M. K.; Levy, G. S.; Stelzried, C. T.; Seidel, B. L.

1977-01-01

The first of two solar occultations of the satellite Helios-1 in 1975 occurred in April when the satellite's ray path approached the west limb of the sun to a minimum distance of 1.63 solar radii. The second occultation took place in late August/early September when Helios-1 was totally eclipsed by the photosphere. Measurements of the polarization angle of the linearly polarized telemetry signal were performed with automatic tracking polarimeters at the 64 m Goldstone Tracking Station in California and also at the 100 m radio telescope in Effelsberg, West Germany. The coronal Faraday rotation as a function of the solar offset for both occultations is shown in graphs. The theoretical significance of the observations is investigated.

Election Verifiability: Cryptographic Definitions and an Analysis of Helios and JCJ

DTIC Science & Technology

2015-08-06

SHA - 256 [98], we assume that H is a random oracle to prove Theorem 2. Moreover, we assume the sigma protocols used by Helios 4.0 satisfy the...Aspects in Security and Trust, volume 5491 of LNCS, pages 242– 256 . Springer, 2008. [68] Martin Hirt. Receipt-Free K-out-of-L Voting Based on ElGamal

West Europe Report

DTIC Science & Technology

1987-05-27

Helios, Syracuse II Satellite Programs Detailed ( Jean -Paul Croize; LE FIGARO, 3 Feb 87) "* Increased Competition, New Markets for Weapons Sales...LIBERATION, 7-8 Mar 87) Problems, Advantages _ South East Asian Market, by Jean Guisnel °" Socialist Policy Shift, Editorial by Pierre Briancon...12466 CSO: 3554/118 73 MILITARY FRANCE HELIOS, SYRACUSE II SATELLITE PROGRAMS DETAILED Paris LE FIGARO in French 3 Feb 87 p 10 ^TLrticle by Jean

The shape and location of the sector boundary surface in the inner solar system. [Helios observations

NASA Technical Reports Server (NTRS)

Villante, U.; Bruno, R.; Mariani, F.; Burlaga, L. F.; Ness, N. F.

1979-01-01

Simultaneous observations by Helios-1 and Helios-2 over four solar rotations were used to determine the latitudinal dependence of the polarity of the interplanetary magnetic field within plus or minus 7.23 deg of the solar equator and within 1 AU. The longitudinal and latitudinal positions of the sector boundary crossing are consistent with a warped sector boundary which extended from the sun to 1 AU and was inclined approximately 10 deg with respect to the heliographic equator. This is consistent with simultaneous Pioneer 11 observations, which showed unipolar fields at latitude approximately 16 deg at heliocentric distances greater than 3.5 AU. Two sectors were observed at southern latitudes; however, four sectors were observed at northern latitudes on two rotations, indicating a distortion from planarity of the sectory boundary surface.

Comparison of ENDF/B-VII.1 and JEFF-3.2 in VVER-1000 operational data calculation

NASA Astrophysics Data System (ADS)

Frybort, Jan

2017-09-01

Safe operation of a nuclear reactor requires an extensive calculational support. Operational data are determined by full-core calculations during the design phase of a fuel loading. Loading pattern and design of fuel assemblies are adjusted to meet safety requirements and optimize reactor operation. Nodal diffusion code ANDREA is used for this task in case of Czech VVER-1000 reactors. Nuclear data for this diffusion code are prepared regularly by lattice code HELIOS. These calculations are conducted in 2D on fuel assembly level. There is also possibility to calculate these macroscopic data by Monte-Carlo Serpent code. It can make use of alternative evaluated libraries. All calculations are affected by inherent uncertainties in nuclear data. It is useful to see results of full-core calculations based on two sets of diffusion data obtained by Serpent code calculations with ENDF/B-VII.1 and JEFF-3.2 nuclear data including also decay data library and fission yields data. The comparison is based directly on fuel assembly level macroscopic data and resulting operational data. This study illustrates effect of evaluated nuclear data library on full-core calculations of a large PWR reactor core. The level of difference which results exclusively from nuclear data selection can help to understand the level of inherent uncertainties of such full-core calculations.

Nanoscience at Work: Creating Energy from Sunlight (LBNL Science at the Theater)

ScienceCinema

Alivisatos, Paul [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2018-02-26

Paul Alivisatos, co-leader of Berkeley Lab's Helios Project, is the Associate Director for Physical Sciences and director of the Materials Sciences Division at Berkeley Lab. In the Helios Project, Alivisatos will use nanotechnology in the efficient capture of sunlight and its conversion to electricity to drive economical fuel production processes. He is an authority on artificial nanostructure synthesis and inventor of the quantum dot technology.

Automatic target alignment of the Helios laser system

NASA Astrophysics Data System (ADS)

Liberman, I.; Viswanathan, V. K.; Klein, M.; Seery, B. D.

1980-05-01

An automatic target-alignment technique for the Helios laser facility is reported and verified experimentally. The desired alignment condition is completely described by an autocollimation test. A computer program examines the autocollimated return pattern from the surrogate target and correctly describes any changes required in mirror orientation to yield optimum target alignment with either aberrated or misaligned beams. Automated on-line target alignment is thus shown to be feasible.

Analysis and prediction of Doppler noise during solar conjunctions

NASA Technical Reports Server (NTRS)

Berman, A. L.; Rockwell, S. T.

1975-01-01

The results of a study of Doppler data noise during solar conjunctions were presented. During the first half of 1975, a sizeable data base of Doppler data noise (estimates) for the Pioneer 10, Pioneer 11, and Helios 1 solar conjunctions was accumulated. To analyze this data, certain physical assumptions are made, leading to the development of a geometric parameter ("ISI") which correlates strongly with Doppler data noise under varying sun-earth-spacecraft geometries. Doppler noise models are then constructed from this parameter, resulting in the newfound ability to predict Doppler data noise during solar conjunctions, and hence to additionally be in a position to validate Doppler data acquired during solar conjunctions.

DoD High Performance Computing Modernization Program FY16 Annual Report

DTIC Science & Technology

2018-05-02

vortex shedding from rotor blade tips using adaptive mesh refinement gives Helios the unique capability to assess the interaction of these vortices...with the fuselage and nearby rotor blades . Helios provides all the benefits for rotary-winged aircraft that Kestrel does for fixed-wing aircraft...rotor blade upgrade of the CH-47F Chinook helicopter to achieve up to an estimated 2,000 pounds increase in hover thrust (~10%) with limited

Helios-2 Vela-Ariel-5 gamma-ray burst source position

NASA Technical Reports Server (NTRS)

Cline, T. L.; Trainor, J. H.; Desai, U. D.; Klebesadel, R. W.; Ricketts, M.; Heluken, H.

1979-01-01

The gamma-ray burst of 28 January 1976, one of 18 events thus far detected in interplanetary space with Helios-2, was also observed with the Vela-5A, -6A and the Ariel-5 satellites. A small source field is obtained from the intersection of the region derived from the observed time delays between Helios-2 and Vela-5A and -6A with the source region independently found with the Ariel-5 X-ray detector. This area contains neither any steady X-ray source as scanned by HEAO-A nor any previously catalogued X-ray, radio or infrared sources, X-ray transients, quasars, seyferts, globular clusters, flare stars, pulsars, white dwarfs or high energy gamma-ray sources. The region is however, within the source field of a gamma-ray transient observed in 1974, which exhibited nuclear gamma-ray line structure.

Helios1A EoL: A Success. For the first Time a Long Final Thrust Scenario, Respecting the French Law on Space Operations

NASA Astrophysics Data System (ADS)

Guerry, Agnes; Moussi, Aurelie; Sartine, Christian; Beaumet, Gregory

2013-09-01

HELIOS1A End Of Live (EOL) operations occurred in the early 2012. Through this EOL operation, CNES wanted to make an example of French Space Act compliance. Because the satellite wasn't natively designed for such an EOL phase, the operation was touchy and risky. It was organized as a real full project in order to assess every scenario details with dedicated Mission Analysis, to secure the operations through detailed risk analysis at system level and to consider the major failures that could occur during the EOL. A short scenario allowing to reach several objectives with benefits was eventually selected. The main objective of this project was to preserve space environment. The operations were led on a "best effort" basis. The French Space Operations Act (FSOA) requirements were met: HELIOS-1A EOL operations had been led successfully.

Overview of the Helios Version 2.0 Computational Platform for Rotorcraft Simulations

NASA Technical Reports Server (NTRS)

Sankaran, Venkateswaran; Wissink, Andrew; Datta, Anubhav; Sitaraman, Jayanarayanan; Jayaraman, Buvna; Potsdam, Mark; Katz, Aaron; Kamkar, Sean; Roget, Beatrice; Mavriplis, Dimitri;

Comportamiento del Helio en estrellas químicamente peculiares

NASA Astrophysics Data System (ADS)

Malaroda, S. M.; López García, Z.; Leone, F.; Catalano, F.

Las estrellas químicamente peculiares (CP) se caracterizan por tener deficiencias y sobreabundancias de algunos elementos químicos de hasta 106 veces la abundancia solar. Además presentan variaciones en las líneas espectrales. Se piensa que ello se debe a que los campos magnéticos presentes en este tipo de estrellas son principalmente dipolares, con un eje de simetría diferente del eje de rotación. La distribución de los elementos sobreabundantes y deficientes no es homogénea sobre la superficie estelar y las variaciones observadas serían una consecuencia directa de la rotación estelar. Entre los elementos con abundancia anómala se encuentra el Helio, cuyas líneas tienen intensidades que no son consistentes con una abundancia normal, que no puede ser determinada del modo usual, o sea, considerando una atmósfera con composición solar. Con el fin de determinar la abundancia de este elemento, se inició un estudio de estrellas anómalas de Helio, Hew y He strong. Además se determinarán las abundancias de otros elementos anómalos como ser el Si, Cr, Mg, Mn y Fe. Las mismas se determinan del modo tradicional, o sea: a) medida de los anchos equivalentes de las líneas de los distintos elementos analizados; b) adopción de la temperatura efectiva, gravedad y abundancia del Helio; c) cálculo del modelo de atmósfera d) comparación con las observaciones y reinicio de un proceso iterativo hasta lograr un acuerdo entre todos los parámetros analizados. Las observaciones se llevaron a cabo en el Complejo Astronómico El Leoncito. Se observaron setenta y ocho estrellas anómalas de Helio. En este momento se está procediendo a calcular las abundancias correspondientes a los distintos elementos químicos. Para ello se hace uso de los modelos de Kurucz, ATLAS9. Los cálculos NLTE de las líneas de Helio se llevan a cabo con el programa MULTI y se compararán con los realizados con el programa WIDTH9 de Kurucz (LTE), con el objeto de resaltar la importancia de los efectos NLTE.

TC-2 post Helios experiment data review. [postflight systems analysis of spacecraft performance

NASA Technical Reports Server (NTRS)

1975-01-01

Data are presented from a systems postflight analysis of the Centaur Launch Vehicle and Helios. Also given is a comparison of data from preflight analyses. Topics examined are: (1) propellant behavior; (2) helium usage; (3) propellant tank pressurization; (4) propellant tank thermodynamics; (5) component heating; thermal control; and thermal protection system; (6) main engine system; (7) H2O2 consumption; (8) boost pump post-meco performance; and (9) an overview of other systems.

The Faraday rotation experiment. [solar corona

NASA Technical Reports Server (NTRS)

Volland, H.; Levy, G. S.; Bird, M. K.; Stelzried, C. T.; Seidel, B. L.

1984-01-01

The magnetized plasma of the solar corona was remotely sounded using the Faraday rotation effect. The solar magnetic field together with the electrons of the coronal plasma cause a measurable Faraday rotation effect, since the radio waves of Helios are linearly polarized. The measurement is performed at the ground stations. Alfven waves traveling from the Sun's surface through the corona into interplanetary space are observed. Helios 2 signals penetrating through a region where coronal mass is ejected show wavelike structures.

Distinctive Regulatory T Cells and Altered Cytokine Profile Locally in the Airways of Young Smokers with Normal Lung Function

PubMed Central

Ostadkarampour, Mahyar; Müller, Malin; Öckinger, Johan; Kullberg, Susanna; Lindén, Anders; Eklund, Anders; Grunewald, Johan; Wahlström, Jan

2016-01-01

Smoking influences the immune system in different ways and, hypothetically, effects on pulmonary effector and regulatory T cells emerge as potentially detrimental. Therefore, we characterized the frequencies and characteristics of CD4+ and CD8+ T cell subsets in the blood and lungs of young tobacco smokers. Bronchoalveolar lavage (BAL) and peripheral blood were obtained from healthy moderate smokers (n = 18; 2–24 pack-years) and never-smokers (n = 15), all with normal lung function. Cells were stimulated ex vivo and key intracellular cytokines (IFNγ, IL-17, IL-10 and TNFα) and transcription factors (Foxp3, T-bet and Helios) were analyzed using flow cytometry. Our results indicate that smoking is associated with a decline in lung IL-17+ CD4+ T cells, increased IFNγ+ CD8+ T cells and these alterations relate to the history of daily cigarette consumption. There is an increased fraction of Foxp3+ regulatory T cells being Helios- in the lungs of smokers. Cytokine production is mainly confined to the Helios- T cells, both in regulatory and effector subsets. Moreover, we detected a decline of Helios+Foxp3- postulated regulatory CD8+ T cells in smokers. These alterations in the immune system are likely to increase risk for infection and may have implications for autoimmune processes initiated in the lungs among tobacco smokers. PMID:27798682

Helios Prototype on lakebed during ground check of electric motors

NASA Technical Reports Server (NTRS)

1999-01-01

The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at Dryden in late 1998. The craft has a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of its solar-powered Pathfinder flying wing, and longer than either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. Helios is one of several remotely-piloted aircraft-also known as uninhabited aerial vehicles or UAV's-being developed as technology demonstrators by several small airframe manufacturers under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project. Developed by AeroVironment, Inc., of Monrovia, Calif., the unique craft is intended to demonstrate two key missions: the ability to reach and sustain horizontal flight at 100,000 feet altitude on a single-day flight, and to maintain flight above 50,000 feet altitude for at least four days, both on electrical power derived from non-polluting solar energy. During later flights, AeroVironment's flight test team will evaluate new motor-control software which may allow the pitch of the aircraft-the nose-up or nose-down attitude in relation to the horizon-to be controlled entirely by the motors. If successful, productions versions of the Helios could eliminate the elevators on the wing's trailing edge now used for pitch control, saving weight and increasing the area of the wing available for installation of solar cells.

Evolución de estrellas de Helio

NASA Astrophysics Data System (ADS)

Panei, J. A.; Benvenuto, O. G.; Althaus, L. G.

Podríamos identificar a las estrellas de helio con estrellas Wolf-Rayet (WR) que han perdido su envoltura rica en hidrógeno ya sea porque las mismas pertenecen a sistemas binarios o a través de fuertes vientos estelares. Las WR representan una etapa evolucionaria normal de las estrellas masivas, cuya pérdida de masa es >= 3 × 10-5Msolar/yr y la cual es sufrida por la estrella en un tiempo de escala mucho menor que el tiempo en que se produce la quema del He. Esto garantiza la ``homogeneidad'' de las estrellas de helio para nuestros modelos. Este tipo de estrellas serían posibles progenitores de SN tipo Ib y Ic. Aquí presentamos un estudio sobre la evolución de estrellas de helio a partir de la secuencia principal de helio, pasando por el flash de carbono, hasta agotarlo en la región central; como así también la dependencia con la variable masa y con la pérdida de la misma para distintos tipos de masas. Para tal fin hemos utilizado un código de evolución estelar completo que realiza todas las reacciones de Fowler en forma simultánea. También se han tenido en cuenta los procesos de mezcla convectiva, los principales mecanismos de emisión de neutrinos y los efectos de la pérdida de masa. Las opacidades utilizadas fueron las de Rogers & Iglesias (1992). Debido a la pérdida de masa en este tipo de estrellas, hemos encontrado que los perfiles convectivos, la composición química, las condiciones centrales de temperatura y presión, luminosidad y temperatura efectiva dependen en forma esencial de la velocidad de pérdida de masa adoptada, lo que tendría profundas implicaciones en la evolución posterior de estos objetos.

A design approach for small vision-based autonomous vehicles

NASA Astrophysics Data System (ADS)

Edwards, Barrett B.; Fife, Wade S.; Archibald, James K.; Lee, Dah-Jye; Wilde, Doran K.

2006-10-01

This paper describes the design of a small autonomous vehicle based on the Helios computing platform, a custom FPGA-based board capable of supporting on-board vision. Target applications for the Helios computing platform are those that require lightweight equipment and low power consumption. To demonstrate the capabilities of FPGAs in real-time control of autonomous vehicles, a 16 inch long R/C monster truck was outfitted with a Helios board. The platform provided by such a small vehicle is ideal for testing and development. The proof of concept application for this autonomous vehicle was a timed race through an environment with obstacles. Given the size restrictions of the vehicle and its operating environment, the only feasible on-board sensor is a small CMOS camera. The single video feed is therefore the only source of information from the surrounding environment. The image is then segmented and processed by custom logic in the FPGA that also controls direction and speed of the vehicle based on visual input.

An embedded vision system for an unmanned four-rotor helicopter

NASA Astrophysics Data System (ADS)

Lillywhite, Kirt; Lee, Dah-Jye; Tippetts, Beau; Fowers, Spencer; Dennis, Aaron; Nelson, Brent; Archibald, James

2006-10-01

In this paper an embedded vision system and control module is introduced that is capable of controlling an unmanned four-rotor helicopter and processing live video for various law enforcement, security, military, and civilian applications. The vision system is implemented on a newly designed compact FPGA board (Helios). The Helios board contains a Xilinx Virtex-4 FPGA chip and memory making it capable of implementing real time vision algorithms. A Smooth Automated Intelligent Leveling daughter board (SAIL), attached to the Helios board, collects attitude and heading information to be processed in order to control the unmanned helicopter. The SAIL board uses an electrolytic tilt sensor, compass, voltage level converters, and analog to digital converters to perform its operations. While level flight can be maintained, problems stemming from the characteristics of the tilt sensor limits maneuverability of the helicopter. The embedded vision system has proven to give very good results in its performance of a number of real-time robotic vision algorithms.

Shock and statistical acceleration of energetic particles in the interplanetary medium

NASA Technical Reports Server (NTRS)

Valdes-Galicia, J. F.; Moussas, X.; Quenby, J. J.; Neubauer, F. M.; Schwenn, R.

1985-01-01

Definite evidence for particle acceleration in the solar wind came around a decade ago. Two likely sources are known to exist: particles may be accelerated by the turbulence resulting from the superposition of Alfven and Magnetosonic waves (Statistical Acceleration) or they may be accelerated directly at shock fronts formed by the interaction of fast and slow solar wind (CIR's) or by traveling shocks due to sporadic coronal mass ejections. Naurally both mechanisms may be operative. In this work the acceleration problem was tackled numerically using Helios 1 and 2 data to create a realistic representation of the Heliospheric plasma. Two 24 hour samples were used: one where there are only wave like fluctuations of the field (Day 90 Helios 1) and another with a shock present in it (Day 92 of Helios 2) both in 1976 during the STIP 2 interval. Transport coefficients in energy space have been calculated for particles injected in each sample and the effect of the shock studied in detail.

Time delay occultation data of the Helios spacecraft for probing the electron density distribution in the solar corona

NASA Technical Reports Server (NTRS)

Edenhofer, P.; Lueneburg, E.; Esposito, P. B.; Martin, W. L.; Zygielbaum, A. I.; Hansen, R. T.; Hansen, S. F.

1978-01-01

S-band time delay measurements were collected from the spacecraft Helios A and B during three solar occultations in 1975/76 within heliocentric distances of about 3 and 215 earth radius in terms of range, Doppler frequency shift, and electron content. Characteristic features of measurement and data processing are described. Typical data sets are discussed to probe the electron density distribution near the sun (west and east limb as well) including the outer and extended corona. Steady-state and dynamical aspects of the solar corona are presented and compared with earth-bound-K-coronagraph measurements. Using a weighted least squares estimation, parameters of an average coronal electron density profile are derived in a preliminary analysis to yield electron densities at r = 3, 65, 215 earth radius. Transient phenomena are discussed and a velocity of propagation v is nearly equal to 900 km/s is determined for plasma ejecta from a solar flare observed during an extraordinary set of Helios B electron content measurements.

AeroVironment technician checks a Helios solar cell panel

NASA Technical Reports Server (NTRS)

2000-01-01

A technician at AeroVironment's Design Development Center in Simi Valley, California, checks a panel of silicon solar cells for conductivity and voltage. The bi-facial cells, fabricated by SunPower, Inc., of Sunnyvale, California, are among 64,000 solar cells which have been installed on the Helios Prototype solar-powered aircraft to provide power to its 14 electric motors and operating systems. Developed by AeroVironment under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the Helios Prototype is the forerunner of a planned fleet of slow-flying, long duration, high-altitude aircraft which can perform atmospheric science missions and serve as telecommunications relay platforms in the stratosphere. Target goals set by NASA for the giant 246-foot span flying wing include reaching and sustaining subsonic horizontal flight at 100,000 feet altitude in 2001, and sustained continuous flight for at least four days and nights above 50,000 feet altitude with the aid of a regenerative fuel cell-based energy storage system now under development in 2003.

The solar-powered Helios Prototype flying wing frames two modified F-15 research aircraft in a hanga

NASA Technical Reports Server (NTRS)

2002-01-01

The solar-powered Helios Prototype flying wing frames two modified F-15 research aircraft in a hangar at NASA's Dryden flight Research Center, Edwards, California. The elongated 247-foot span lightweight aircraft, resting on its ground maneuvering dolly, stretched almost the full length of the 300-foot long hangar while on display during a visit of NASA Administrator Sean O'Keefe and other NASA officials on Jan. 31, 2002. The unique solar-electric flying wing reached an altitude of 96,863 feet during an almost 17-hour flight near Hawaii on Aug. 13, 2001, a world record for sustained horizontal flight by a non-rocket powered aircraft. Developed by AeroVironment, Inc., under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the Helios Prototype is the forerunner of a planned fleet of slow-flying, long duration, high-altitude uninhabited aerial vehicles (UAV) which can serve as 'atmospheric satellites,' performing Earth science missions or functioning as telecommunications relay platforms in the stratosphere.

Traceable Radiometry Underpinning Terrestrial- and Helio- Studies (TRUTHS)

USGS Publications Warehouse

Fox, N.; Aiken, J.; Barnett, J.J.; Briottet, X.; Carvell, R.; Frohlich, C.; Groom, S.B.; Hagolle, O.; Haigh, J.D.; Kieffer, H.H.; Lean, J.; Pollock, D.B.; Quinn, T.; Sandford, M.C.W.; Schaepman, M.; Shine, K.P.; Schmutz, W.K.; Teillet, P.M.; Thome, K.J.; Verstraete, M.M.; Zalewski, E.; ,

2002-01-01

The Traceable Radiometry Underpinning Terrestrial- and Helio- Studies (TRUTHS) mission offers a novel approach to the provision of key scientific data with unprecedented radiometric accuracy for Earth Observation (EO) and solar studies, which will also establish well-calibrated reference targets/standards to support other EO missions. This paper will present the TRUTHS mission and its objectives. TRUTHS will be the first satellite mission to calibrate its instrumentation directly to SI in orbit, overcoming the usual uncertainties associated with drifts of sensor gain and spectral shape by using an electrical rather than an optical standard as the basis of its calibration. The range of instruments flown as part of the payload will also provide accurate input data to improve atmospheric radiative transfer codes by anchoring boundary conditions, through simultaneous measurements of aerosols, particulates and radiances at various heights. Therefore, TRUTHS will significantly improve the performance and accuracy of Earth observation missions with broad global or operational aims, as well as more dedicated missions. The provision of reference standards will also improve synergy between missions by reducing errors due to different calibration biases and offer cost reductions for future missions by reducing the demands for on-board calibration systems. Such improvements are important for the future success of strategies such as Global Monitoring for Environment and Security (GMES) and the implementation and monitoring of international treaties such as the Kyoto Protocol. TRUTHS will achieve these aims by measuring the geophysical variables of solar and lunar irradiance, together with both polarised and un-polarised spectral radiance of the Moon, and the Earth and its atmosphere.

Traceable Radiometry Underpinning Terrestrial - and Helio- Studies (TRUTHS)

USGS Publications Warehouse

Fox, N.; Aiken, J.; Barnett, J.J.; Briottet, X.; Carvell, R.; Frohlich, C.; Groom, S.B.; Hagolle, O.; Haigh, J.D.; Kieffer, H.H.; Lean, J.; Pollock, D.B.; Quinn, T.; Sandford, M.C.W.; Schaepman, M.; Shine, K.P.; Schmutz, W.K.; Teillet, P.M.; Thome, K.J.; Verstraete, M.M.; Zalewski, E.

2003-01-01

The Traceable Radiometry Underpinning Terrestrial- and Helio- Studies (TRUTHS) mission offers a novel approach to the provision of key scientific data with unprecedented radiometric accuracy for Earth Observation (EO) and solar studies, which will also establish well-calibrated reference targets/standards to support other EO missions. This paper presents the TRUTHS mission and its objectives. TRUTHS will be the first satellite mission to calibrate its EO instrumentation directly to SI in orbit, overcoming the usual uncertainties associated with drifts of sensor gain and spectral shape by using an electrical rather than an optical standard as the basis of its calibration. The range of instruments flown as part of the payload will also provide accurate input data to improve atmospheric radiative transfer codes by anchoring boundary conditions, through simultaneous measurements of aerosols, particulates and radiances at various heights. Therefore, TRUTHS will significantly improve the performance and accuracy of EO missions with broad global or operational aims, as well as more dedicated missions. The provision of reference standards will also improve synergy between missions by reducing errors due to different calibration biases and offer cost reductions for future missions by reducing the demands for on-board calibration systems. Such improvements are important for the future success of strategies such as Global Monitoring for Environment and Security (GMES) and the implementation and monitoring of international treaties such as the Kyoto Protocol. TRUTHS will achieve these aims by measuring the geophysical variables of solar and lunar irradiance, together with both polarised and unpolarised spectral radiance of the Moon, Earth and its atmosphere. Published by Elsevier Ltd of behalf of COSPAR.

Effects of particle size, helium gas pressure and microparticle dose on the plasma concentration of indomethacin after bombardment of indomethacin-loaded poly-L-lactic acid microspheres using a Helios gun system.

PubMed

Uchida, Masaki; Natsume, Hideshi; Kobayashi, Daisuke; Sugibayashi, Kenji; Morimoto, Yasunori

2002-05-01

We investigated the effects of the particle size of indomethacin-loaded poly-L-lactic acid microspheres (IDM-loaded PLA MS), the helium pressure used to accelerate the particles, and the bombardment dose of PLA MS on the plasma concentration of IDM after bombarding with IDM-loaded PLA MS of different particle size ranges, 20-38, 44-53 and 75-100 microm, the abdomen of hairless rats using the Helios gene gun system (Helios gun system). Using larger particles and a higher helium pressure, produced an increase in the plasma IDM concentration and the area under the plasma concentration-time curve (AUC) and resultant F (relative bioavailability with respect to intracutaneous injection) of IDM increased by an amount depending on the particle size and helium pressure. Although a reduction in the bombardment dose led to a decrease in C(max) and AUC, F increased on decreasing the bombardment dose. In addition, a more efficient F was obtained after bombarding with IDM-loaded PLA MS of 75-100 microm in diameter at each low dose in different sites of the abdomen compared with that after bolus bombardment with a high dose (dose equivalent). These results suggest that the bombardment injection of drug-loaded microspheres by the Helios gun system is a very useful tool for delivering a variety of drugs in powder form into the skin and systemic circulation.

Relativity experiment on Helios - A status report

NASA Technical Reports Server (NTRS)

Anderson, J. D.; Melbourne, W. G.; Cain, D. L.; Lau, E. K.; Wong, S. K.; Kundt, W.

1975-01-01

The relativity experiment on Helios (Experiment 11) uses S-band and Doppler data, and spacecraft-solar-orbital data to measure the effects of general relativity in the solar system and the quadrupole moment in the solar gravitational field. Specifically, Experiment 11 is converned with measuring the following effects: (1) relativistic orbital corrections described by two parameters of the space-time metric which are both equal to unity in Einstein's theory; (2) orbital perturbations caused by a finite quadrupole moment of an oblate sun, described by zonal harmonics in the solar gravitational field.

The Energy Problem: What the Helios Project Can Do About it (LBNL Science at the Theater)

ScienceCinema

Chu, Steven

2018-06-15

The energy problem is one of the most important issues that science and technology has to solve. Nobel laureate and Berkeley Lab Director Steven Chu proposes an aggressive research program to transform the existing and future energy systems of the world away from technologies that emit greenhouse gases. Berkeley Lab's Helios Project concentrates on renewable fuels, such as biofuels, and solar technologies, including a new generation of solar photovoltaic cells and the conversion of electricity into chemical storage to meet future demand.

Disturbing effects of attitude control maneuvers on the orbital motion of the Helios spacecraft

NASA Technical Reports Server (NTRS)

Georgevic, R. M.

1976-01-01

The position of the spin axis of the Helios A spacecraft has been maintained and updated by a series of attitude control maneuvers, by means of a sequence of unbalanced jet forces which produce an additional disturbed motion of the spacecraft's center of mass. The character of this motion, its magnitude and direction was studied. For practical purposes of the orbit determination of the spacecraft, a computer program is given which shows how the components of the disturbing acceleration in the spacecraft-fixed reference frame can be easily computed.

The effects of 8 Helios observed solar proton events of interplanetary magnetic field fluctuations

NASA Technical Reports Server (NTRS)

ValdezGalicia, J. F.; Alexander, P.; Otaola, J. A.

1995-01-01

There have been recent suggestions that large fluxes during solar energetic particle events may produce their own turbulence. To verify this argument it becomes essential to find out whether these flows cause an enhancement of interplanetary magnetic field fluctuations. In the present work, power and helicity spectra of the IMF before, during and after 8 Helios-observed solar proton events in the range 0.3 - 1 AU are analyzed. In order to detect proton self generated waves, the time evolution of spectra are followed.

Generation of temperature anisotropy for alpha particle velocity distributions in solar wind at 0.3 AU: Vlasov simulations and Helios observations

NASA Astrophysics Data System (ADS)

Perrone, D.; Bourouaine, S.; Valentini, F.; Marsch, E.; Veltri, P.

2014-04-01

Solar wind "in situ" measurements from the Helios spacecraft in regions of the Heliosphere close to the Sun (˜0.3 AU), at which typical values of the proton plasma beta are observed to be lower than unity, show that the alpha particle distribution functions depart from the equilibrium Maxwellian configuration, displaying significant elongations in the direction perpendicular to the background magnetic field. In the present work, we made use of multi-ion hybrid Vlasov-Maxwell simulations to provide theoretical support and interpretation to the empirical evidences above. Our numerical results show that, at variance with the case of βp≃1 discussed in Perrone et al. (2011), for βp=0.1 the turbulent cascade in the direction parallel to the ambient magnetic field is not efficient in transferring energy toward scales shorter than the proton inertial length. Moreover, our numerical analysis provides new insights for the theoretical interpretation of the empirical evidences obtained from the Helios spacecraft, concerning the generation of temperature anisotropy in the particle velocity distributions.

Technician Marshall MacCready installs solar cells on the Helios Prototype

NASA Technical Reports Server (NTRS)

2000-01-01

Technician Marshall MacCready carefully lays a panel of solar cells into place on a wing section of the Helios Prototype flying wing at AeroVironment's Design Development Center in Simi Valley, California. The bi-facial cells, manufactured by SunPower, Inc., of Sunnyvale, California, are among 64,000 solar cells which have been installed on the solar-powered aircraft to provide electricity to its 14 motors and operating systems. Developed by AeroVironment under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the Helios Prototype is the forerunner of a planned fleet of slow-flying, long duration, high-altitude aircraft which can perform atmospheric science missions and serve as telecommunications relay platforms in the stratosphere. Target goals set by NASA for the giant 246-foot span flying wing include reaching and sustaining subsonic horizontal flight at 100,000 feet altitude in 2001, and sustained continuous flight for at least four days and nights above 50,000 feet altitude 2003 with the aid of a regenerative fuel cell-based energy storage system now being developed.

The 1976 Helios and Pioneer solar conjunctions-continuing corroboration of the link between Doppler noise and integrated signal path electron density

NASA Technical Reports Server (NTRS)

Berman, A. L.; Wackley, J. A.; Rockwell, S. T.

1976-01-01

Observed Doppler noise (rms phase jitter) from the 1976 solar conjunctions of the Helios 1 and 2 and the Pioneer 10 and 11 spacecraft was processed with a recently developed Doppler noise model ISEDB. Good agreement is obtained between the observed data and the model. Correlation is shown between deviations from the ISEDB model and sunspot activity, but it is insufficient to be modeled. Correlation is also shown between ISEDB model deviations for (spacecraft) signal paths on the same side of the sun.

Gaia, Helios, Selene and Ouranos: the three principal celestial bodies and the sky in the ancient Greek cosmogony

NASA Astrophysics Data System (ADS)

Theodossiou, Efstratios; Manimanis, Vassilios N.; Dimitrijević, Milan S.; Mantarakis, Petros

In this article we consider the role of the three principal celestial bodies, the Earth (Gaia), the Sun (Helios) and the Moon (Selene), as well as the Sky (Ouranos) in the ancient Greek cosmogony. This is done by the analysis of antique Greek texts like Orphic Hymns and the literary remains of the writers and philosophers like Aeschylus, (Pseudo) Apollodorus, Apollonius Rhodius, Aristotle, Euripides, Hesiod, Homer, Hyginus, Nonnus, Pausanias, Pindar and Sophocles, as well as by the analysis of texts of Roman writers like Cicero, Ovid and Pliny.

A model for sequential decoding overflow due to a noisy carrier reference. [communication performance prediction

NASA Technical Reports Server (NTRS)

Layland, J. W.

1974-01-01

An approximate analysis of the effect of a noisy carrier reference on the performance of sequential decoding is presented. The analysis uses previously developed techniques for evaluating noisy reference performance for medium-rate uncoded communications adapted to sequential decoding for data rates of 8 to 2048 bits/s. In estimating the ten to the minus fourth power deletion probability thresholds for Helios, the model agrees with experimental data to within the experimental tolerances. The computational problem involved in sequential decoding, carrier loop effects, the main characteristics of the medium-rate model, modeled decoding performance, and perspectives on future work are discussed.

Statistical properties of MHD fluctuations associated with high speed streams from HELIOS 2 observations

NASA Technical Reports Server (NTRS)

Bavassano, B.; Dobrowolny, H.; Fanfoni, G.; Mariani, F.; Ness, N. F.

1981-01-01

Helios 2 magnetic data were used to obtain several statistical properties of MHD fluctuations associated with the trailing edge of a given stream served in different solar rotations. Eigenvalues and eigenvectors of the variance matrix, total power and degree of compressibility of the fluctuations were derived and discussed both as a function of distance from the Sun and as a function of the frequency range included in the sample. The results obtained add new information to the picture of MHD turbulence in the solar wind. In particular, a dependence from frequency range of the radial gradients of various statistical quantities is obtained.

Data processing for a cosmic ray experiment onboard the solar probes Helios 1 and 2: Experiment 6

NASA Technical Reports Server (NTRS)

Mueller-Mellin, R.; Green, G.; Iwers, B.; Kunow, H.; Wibberenz, G.; Fuckner, J.; Hempe, H.; Witte, M.

1982-01-01

The data processing system for the Helios experiment 6, measuring energetic charged particles of solar, planetary and galactic origin in the inner solar system, is described. The aim of this experiment is to extend knowledge on origin and propagation of cosmic rays. The different programs for data reduction, analysis, presentation, and scientific evaluation are described as well as hardware and software of the data processing equipment. A chronological presentation of the data processing operation is given. Procedures and methods for data analysis which were developed can be used with minor modifications for analysis of other space research experiments.

Infrared Smartt Interferometer As An Alignment Tool For Carbon Dioxide Laser Fusion Systems

NASA Astrophysics Data System (ADS)

Viswanathan, V. K.; Bolen, P. D.

1980-11-01

It is essential to minimize the pointing and focusing errors at the focal plane for many applications involving infrared laser systems. In the case of the LASL CO2 laser fusion systems, with two beams in the Gemini System and eight beams in the Helios System, this is particularly important. The LASL Helios CO2 Laser Fusion System has eight 34-cm diameter beams emerging from the power amplifier and each beam is brought to focus by an off-aperture parabola (nearly 77.3-cm focal length) resulting in a nearly F/2.4 beam at the focal plane. The design tolerance at the focal plane for pointing accuracy is +/- 25 microns and for focusing accuracy is +/- 50 microns for this system. This paper describes an alignment scheme based on the use of the infrared Smartt interferometer' and compares the results obtained using this technique and the autocollimating Hartmann scheme2 in a laboratory setup duplicating the target chamber region of one of the beams of the Helios System. The results using the Smartt interferometer show that pointing accuracy of +/- 12.5 microns and focusing accuracies of ± 15 microns are obtained at the focal plane of the system.

A Review of Solar-Powered Aircraft Flight Activity at the Pacific Missile Range Test Facility, Kauai, Hawaii

NASA Technical Reports Server (NTRS)

Ehernberger, L. J.; Donohue, Casey; Teets, Edward H., Jr.

2004-01-01

A series of solar-powered aircraft have been designed and operated by AeroVironment, Inc. (Monrovia, CA) as a part of National Aeronautics and Space Administration (NASA) objectives to develop energy-efficient high-altitude long-endurance platforms for earth observations and communications applications. Flight operations have been conducted at NASA's Dryden Flight Research Center, Edwards CA and at the U.S. Navy Pacific Missile Range Facility (PMRF) at Barking Sands, Kauai, HI. These aircraft flown at PMRF are named Pathfinder , Pathfinder Plus and Helios . Sizes of these three aircraft range from 560 lb with a 99-ft wingspan to 2300 lb with a 247-ft wingspan. Available payload capacity reaches approximately 200 lb. Pathfinder uses six engines and propellers: Pathfinder Plus 8; and Helios 14. The 2003 Helios fuel cell configurations used 10 engines and propellers. The PMRF was selected as a base of operations because if offers optimal summertime solar exposure, low prevailing wind-speeds on the runway, modest upper-air wind-speeds and the availability of suitable airspace. Between 1997 and 2001, successive altitude records of 71,530 ft, 80,200 ft, and 96,863 ft were established. Flight durations extended to 18 hours.

Ion acoustic waves in the solar wind

NASA Technical Reports Server (NTRS)

Gurnett, D. A.; Frank, L. A.

1978-01-01

Plasma wave measurements on the Helios 1 and 2 spacecraft have revealed the occurrence of electric field turbulence in the solar wind at frequencies between the electron and ion plasma frequencies. Wavelength measurements with the Imp 6 spacecraft now provide strong evidence that these waves are shortwavelength ion acoustic waves which are Doppler-shifted upward in frequency by the motion of the solar wind. Comparison of the Helios results with measurements from the earth-orbiting Imp 6 and 8 spacecraft shows that the ion acoustic wave turbulence detected in interplanetary space has characteristics essentially identical to those of bursts of electrostatic turbulence generated by protons streaming into the solar wind from the earth's bow shock. In a few cases, enhanced ion acoustic wave intensities have been observed in direct association with abrupt increases in the anisotropy of the solar wind electron distribution. This relationship strongly suggests that the ion acoustic waves detected by Helios far from the earth are produced by an electron heat flux instability, as was suggested by Forslund. Possible related mechanisms which could explain the generation of ion acoustic waves by protons streaming into the solar wind from the earth's bow shock are also considered.

Real-time In-Flight Strain and Deflection Monitoring with Fiber Optic Sensors

NASA Technical Reports Server (NTRS)

Richards, Lance; Parker, Allen R.; Ko, William L.; Piazza, Anthony

2008-01-01

This viewgraph presentation reviews Dryden's efforts to develop in-flight monitoring based on Fiber Optics. One of the motivating factors for this development was the breakup of the Helios aircraft. On Ikhana the use of fiber optics for wing shape sensing is being developed. They are being used to flight validate fiber optic sensor measurements and real-time wing shape sensing predictions on NASA's Ikhana vehicle; validate fiber optic mathematical models and design tools; Assess technical viability and, if applicable, develop methodology and approach to incorporate wing shape measurements within the vehicle flight control system, and develop and flight validate advanced approaches to perform active wing shape control.

Interplanetary particles and fields, November 22 to December 6, 1977 - Helios, Voyager and Imp observations between 0.6 and 1.6 AU

NASA Technical Reports Server (NTRS)

Burlaga, L.; Lepping, R.; Weber, R.; Armstrong, T.; Goodrich, C.; Sullivan, J.; Gurnett, D.; Kellogg, P.; Keppler, E.; Mariani, F.

1980-01-01

The paper presents a wealth of data obtained at approximately 0.6, 1, and 1.6 AU by Helios 1 and 2, Voyager 1 and 2, and Imp 7 and 8, describing the evolution and interactions of particles, flows, and fields in the period 22 November to 6 December 1977. Three flow systems were observed in the period under consideration: (1) a corotating stream and a stream interface associated with a coronal hole; (2) a shock wave and an energetic particle event associated with a 2B flare; and (3) an isolated shock wave of uncertain origin. These phenomena are discussed in some detail.

Renewable Energy from Synthetic Biology (LBNL Science at the Theater)

ScienceCinema

Keasling, Jay [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2018-05-25

Jay Keasling, co-leader of Berkeley Lab's Helios Project, is a groundbreaking researcher in the new scientific field of synthetic biology. In Helios, he directs the biology program, incorporating a range of approaches to increasing the efficacy and economy of plants and cellulose-degrading microbes to make solar-based fuels. He is a UC Berkeley professor of Chemical and Bioengineering, and founder of Amyris Biotechnologies, a company that was honored as a Technology Pioneer for 2006 by the World Economic Forum. Keasling has succeeded in using synthetic biology to develop a yeast-based production scheme for precursors of the antimalarial drug artemisinin in work funded by the Bill & Melinda Gates Foundation.

Renewable Energy from Synthetic Biology (LBNL Science at the Theater)

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

Keasling, Jay

2007-06-04

Jay Keasling, co-leader of Berkeley Lab's Helios Project, is a groundbreaking researcher in the new scientific field of synthetic biology. In Helios, he directs the biology program, incorporating a range of approaches to increasing the efficacy and economy of plants and cellulose-degrading microbes to make solar-based fuels. He is a UC Berkeley professor of Chemical and Bioengineering, and founder of Amyris Biotechnologies, a company that was honored as a Technology Pioneer for 2006 by the World Economic Forum. Keasling has succeeded in using synthetic biology to develop a yeast-based production scheme for precursors of the antimalarial drug artemisinin in workmore » funded by the Bill & Melinda Gates Foundation.« less

Inner Structure of CME Shock Fronts Revealed by the Electromotive Force and Turbulent Transport Coefficients in Helios-2 Observations

NASA Astrophysics Data System (ADS)

Bourdin, Philippe-A.; Hofer, Bernhard; Narita, Yasuhito

2018-03-01

Electromotive force is an essential quantity in dynamo theory. During a coronal mass ejection (CME), magnetic helicity gets decoupled from the Sun and advected into the heliosphere with the solar wind. Eventually, a heliospheric magnetic transient event might pass by a spacecraft, such as the Helios space observatories. Our aim is to investigate the electromotive force, the kinetic helicity effect (α term), the turbulent diffusion (β term), and the cross-helicity effect (γ term) in the inner heliosphere below 1 au. We set up a one-dimensional model of the solar wind velocity and magnetic field for a hypothetic interplanetary CME. Because turbulent structures within the solar wind evolve much slower than this structure needs to pass by the spacecraft, we use a reduced curl operator to compute the current density and vorticity. We test our CME shock-front model against an observed magnetic transient that passes by the Helios-2 spacecraft. At the peak of the fluctuations in this event we find strongly enhanced α, β, and γ terms, as well as a strong peak in the total electromotive force. Our method allows us to automatically identify magnetic transient events from any in situ spacecraft observations that contain magnetic field and plasma velocity data of the solar wind.

Bioclimate and city planning - open space planning

NASA Astrophysics Data System (ADS)

Mertens, Elke

The planning and using of open spaces in urban areas very much depend on the shading of the surrounding building structures. This article presents a method for the investigation of the sunlight and the bioclimatic conditions in dependence on the surrounding buildings. It is illustrated for typical courtyards in Berlin, Germany, as one type of open spaces. The programme HelioDat determines the shading of any spot of an open space. It gives the possible duration of direct sunlight for the selected spot for each day of the year. The sunlight conditions in the courtyards differ from one another a lot in dependence on their size the tallness of the surrounding buildings. The calculation of the PMV on the basis of the results of the programme HelioDat determine the bioclimatic situation in the discussed courtyards. Although the results of HelioDat are only one input among the weather conditions and the personal characteristics of the test-person, the bioclimatic conditions correlate very much with the sunlight conditions. In a projected building structure, the sunlight conditions vary a lot between the present situation and the two architectural alternatives. Since the bioclimatic situation is correlated to the sunlight conditions, this example demonstrates the importance for the investigation of the sunlight conditions and the bioclimate already during the planning process of buildings.

Expression of TIGIT and FCRL3 is Altered in T Cells from Patients with Distinct Patterns of Chronic Autoimmune Thyroiditis.

PubMed

Štefanić, Mario; Tokić, Stana; Suver-Stević, Mirjana; Glavaš-Obrovac, Ljubica

2018-06-11

Co-inhibitory receptors (IR), such as TIGIT and FCRL3, provide a checkpoint against highly destructive immune responses. Co-expression of TIGIT and FCRL3, in particular, has been linked to the HELIOS + subset of regulatory CD4 + FOXP3 + T-cells. Of these, CD4 + FOXP3-exon(E)2 + cells have higher expression of IR and exhibit strongest suppressive properties. Nevertheless, how the expression of TIGIT, FCRL3, HELIOS, and FOXP3E2 is regulated in chronic autoimmune thyroiditis (AT), is not known. Thirty patients with AT [encompassing spontaneously euthyroid (euAT), hypothyroid-untreated and L-thyroxine-treated cases)] and 10 healthy controls (HC) were recruited. FCRL3, TIGIT, HELIOS and FOXP3E2 mRNA expression levels in peripheral blood (PB) T cells were measured via quantitative real-time PCR and compared to clinicopathological factors. The TIGIT and FCRL3 expression levels from T cells of AT cases were inversely related to the thyroid volume, and were significantly increased in hypothyroid patients (on+off L-thyroxine), but not euAT cases. The FCRL3 expression in PB T cells positively correlated with thyroid-peroxidase autoantibody levels; by contrast, T cells from aged AT patients and combined samples (AT+HC) accumulated more TIGIT mRNA. The patients with higher TIGIT mRNA levels had a greater prevalence of hypothyroidism, showing higher peak thyrotropin levels at diagnosis or at follow-up. Multiple IR, namely FCRL3 and TIGIT, but not the transcription factors HELIOS and FOXP3E2, showed increased mRNA levels in PB T cells from end-stage, long-standing and/or more aggressive AT, in proportion to disease severity. A relation with major clinical subphenotypes was observed, thereby identifying IR as potentially important players in AT. © Georg Thieme Verlag KG Stuttgart · New York.

Helios: a Multi-Purpose LIDAR Simulation Framework for Research, Planning and Training of Laser Scanning Operations with Airborne, Ground-Based Mobile and Stationary Platforms

NASA Astrophysics Data System (ADS)

Bechtold, S.; Höfle, B.

2016-06-01

In many technical domains of modern society, there is a growing demand for fast, precise and automatic acquisition of digital 3D models of a wide variety of physical objects and environments. Laser scanning is a popular and widely used technology to cover this demand, but it is also expensive and complex to use to its full potential. However, there might exist scenarios where the operation of a real laser scanner could be replaced by a computer simulation, in order to save time and costs. This includes scenarios like teaching and training of laser scanning, development of new scanner hardware and scanning methods, or generation of artificial scan data sets to support the development of point cloud processing and analysis algorithms. To test the feasibility of this idea, we have developed a highly flexible laser scanning simulation framework named Heidelberg LiDAR Operations Simulator (HELIOS). HELIOS is implemented as a Java library and split up into a core component and multiple extension modules. Extensible Markup Language (XML) is used to define scanner, platform and scene models and to configure the behaviour of modules. Modules were developed and implemented for (1) loading of simulation assets and configuration (i.e. 3D scene models, scanner definitions, survey descriptions etc.), (2) playback of XML survey descriptions, (3) TLS survey planning (i.e. automatic computation of recommended scanning positions) and (4) interactive real-time 3D visualization of simulated surveys. As a proof of concept, we show the results of two experiments: First, a survey planning test in a scene that was specifically created to evaluate the quality of the survey planning algorithm. Second, a simulated TLS scan of a crop field in a precision farming scenario. The results show that HELIOS fulfills its design goals.

Helios expression and Foxp3 TSDR methylation of IFNy+ and IFNy- Treg from kidney transplant recipients with good long-term graft function.

PubMed

Trojan, Karina; Unterrainer, Christian; Weimer, Rolf; Bulut, Nuray; Morath, Christian; Aly, Mostafa; Zhu, Li; Opelz, Gerhard; Daniel, Volker

2017-01-01

There is circumstantial evidence that IFNy+ Treg might have clinical relevance in transplantation. IFNy+ Treg express IFNy receptors and are induced by IFNy. In the present study we investigated in kidney transplant recipients with good long-term stable graft function the absolute cell counts of IFNy+ Treg subsets and whether their expression of Foxp3 is stable or transient. Helios expression determined by eight-color-fluorescence flow cytometry and methylation status of the Foxp3 Treg specific demethylation region (TSDR) served as indicators for stability of Foxp3 expression. Methylation status was investigated in enriched IFNy+ and IFNy- Treg preparations originating from peripheral blood using high resolution melt analysis. A total of 136 transplant recipients and 52 healthy controls were studied. Proportions of IFNy+ Treg were similar in patients and healthy controls (0.05% and 0.04% of all CD4+ lymphocytes; p = n.s.). Patients also had similar absolute counts of IFNy producing Helios+ and Helios- Treg (p = n.s.). Most of the IFNy+ and IFNy- Treg in transplant recipients had a methylated Foxp3 TSDR, however, there was a sizeable proportion of IFNy+ and IFNy- Treg with demethylated Foxp3 TSDR. Male and female patients showed more frequently methylated IFNy+ and IFNy- Treg than male and female controls (all p<0.05). Kidney transplant recipients with good long-term stable graft function have similar levels of IFNy+ Treg as healthy controls. IFNy+ and IFNy- Treg subsets in patients consist of cells with stable and cells with transient Foxp3 expression; however, patients showed more frequently methylated IFNy+ and IFNy- Treg than controls. The data show increased levels of Treg subsets with stable as well as transient Foxp3 expression in patients with stable allograft acceptance compared to healthy controls.

Magnetic fields and flows between 1 AU and 0.3 AU during the primary mission of HELIOS 1

NASA Technical Reports Server (NTRS)

Burlaga, L. F.; Ness, N. F.; Mariani, F.; Bavassano, B.; Villante, U.; Rosenbauer, H.; Schwenn, R.; Harvey, J.

1978-01-01

The recurrent flow and field patterns observed by HELIOS 1, and the relation between these patterns and coronal holes are discussed. Four types of recurrent patterns were observed: a large recurrent stream, a recurrent slow (quiet) flow, a rapidly evolving flow, and a recurrent compound stream. There recurrent streams were not stationary, for although the sources recurred at approximately the same longitudes on successive rotations, the shapes and latitudinal patterns changed from one rotation to the next. A type of magnetic field and plasma structure characterized by a low ion temperature and a high magnetic field intensity is described as well as the structures of stream boundaries between the sun at approximately 0.3 AU.

The University of Iowa Helios solar wind plasma wave experiment /E 5a/. [using spectrum analyzer-electric field antenna system

NASA Technical Reports Server (NTRS)

Gurnett, D. A.; Anderson, R. R.; Odem, D. L.

1975-01-01

This document describes the University of Iowa solar wind plasma wave experiment for the Helios missions (Experiment 5a). The objective of this experiment is the investigation of naturally occurring plasma instabilities and electromagnetic waves in the solar wind. To carry out this investigation, the experiment consists primarily of a 16-channel spectrum analyzer connected to the electric field antennas. The spectrum analyzer covers the frequency range from 20 Hz to 200 kHz and has an amplitude dynamic range which extends from .3 microvolts/m to 30 mV/m per channel. This spectrum analyzer, the antenna potential measurements, the shock alarm system and the supporting electronics are discussed in detail.

Impulsive acceleration and scatter-free transport of about 1 MeV per nucleon ions in (He-3)-rich solar particle events

NASA Technical Reports Server (NTRS)

Mason, G. M.; Ng, C. K.; Klecker, B.; Green, G.

1989-01-01

Impulsive solar energetic particle (SEP) events are studied to: (1) describe a distinct class of SEP ion events observed in interplanetary space, and (2) test models of focused transport through detailed comparisons of numerical model prediction with the data. An attempt will also be made to describe the transport and scattering properties of the interplanetary medium during the times these events are observed and to derive source injection profiles in these events. ISEE 3 and Helios 1 magnetic field and plasma data are used to locate the approximate coronal connection points of the spacecraft to organize the particle anisotropy data and to constrain some free parameters in the modeling of flare events.

Fiber Optic Wing Shape Sensing on NASA's Ikhana UAV

NASA Technical Reports Server (NTRS)

Richards, Lance; Parker, Allen R.; Ko, William L.; Piazza, Anthony

2008-01-01

This document discusses the development of fiber optic wing shape sensing on NASA's Ikhana vehicle. The Dryden Flight Research Center's Aerostructures Branch initiated fiber-optic instrumentation development efforts in the mid-1990s. Motivated by a failure to control wing dihedral resulting in a mishap with the Helios aircraft, new wing displacement techniques were developed. Research objectives for Ikhana included validating fiber optic sensor measurements and real-time wing shape sensing predictions; the validation of fiber optic mathematical models and design tools; assessing technical viability and, if applicable, developing methodology and approaches to incorporate wing shape measurements within the vehicle flight control system; and, developing and flight validating approaches to perform active wing shape control using conventional control surfaces and active material concepts.

Quasi-heterogeneous efficient 3-D discrete ordinates CANDU calculations using Attila

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

Preeti, T.; Rulko, R.

2012-07-01

In this paper, 3-D quasi-heterogeneous large scale parallel Attila calculations of a generic CANDU test problem consisting of 42 complete fuel channels and a perpendicular to fuel reactivity device are presented. The solution method is that of discrete ordinates SN and the computational model is quasi-heterogeneous, i.e. fuel bundle is partially homogenized into five homogeneous rings consistently with the DRAGON code model used by the industry for the incremental cross-section generation. In calculations, the HELIOS-generated 45 macroscopic cross-sections library was used. This approach to CANDU calculations has the following advantages: 1) it allows detailed bundle (and eventually channel) power calculationsmore » for each fuel ring in a bundle, 2) it allows the exact reactivity device representation for its precise reactivity worth calculation, and 3) it eliminates the need for incremental cross-sections. Our results are compared to the reference Monte Carlo MCNP solution. In addition, the Attila SN method performance in CANDU calculations characterized by significant up scattering is discussed. (authors)« less

Possible helio-geomagnetic activity influence on cardiological cases

NASA Astrophysics Data System (ADS)

Katsavrias, Christos

Eruptive solar events as flares and coronal mass ejections (CMEs) occur during solar activ-ity periods. Energetic particles, fast solar wind plasma and electromagnetic radiation pass through interplanetary space, arrive on Earth's ionosphere-magnetosphere and produce various disturbances. It is well known the negative influence of geomagnetic substorms on the human technological applications on geospace. During the last 25 years, many studies concerning the possible influence on the human health are published. Increase of the Acute Coronary Syn-dromes and disorders of the Cardiac Rhythm, increase of accidents as well as neurological and psychological disorders (e.g. increase of suicides) during or near to the geomagnetic storms time interval are reported. In this study, we research the problem in Greece, focusing on patients with Acute Myocardial Infraction, hospitalized in the 2nd Cardiological Department of the General Hospital of Nikaea (Piraeus City), for the time interval 1997-2007 (23rd solar cycle) and also to the arrival of emergency cardiological cases to Emergency Department of two greek hospitals, the General Hospital of Lamia City and the General Hospital of Veria City during the selected months, with or without helio-geomagnetic activity, of the 23rd solar cycle. Increase of cases is recorded during the periods with increase helio-geomagnetic activity. The necessity of continuing the research for a longer period and with a bigger sample is high; so as to exact more secure conclusions.

HelioTrope: An innovative and efficient prototype for solar power production

NASA Astrophysics Data System (ADS)

Papageorgiou, George; Maimaris, Athanasios; Hadjixenophontos, Savvas; Ioannou, Petros

2014-12-01

The solar energy alternative could provide us with all the energy we need as it exist in vast quantities all around us. We only should be innovative enough in order to improve the efficiency of our systems in capturing and converting solar energy in usable forms of power. By making a case for the solar energy alternative, we identify areas where efficiency can be improved and thereby Solar Energy can become a competitive energy source. This paper suggests an innovative approach to solar energy power production, which is manifested in a prototype given the name HelioTrope. The Heliotrope Solar Energy Production prototype is tested on its' capabilities to efficiently covert solar energy to generation of electricity and other forms of energy for storage or direct use. HelioTrope involves an innovative Stirling engine design and a parabolic concentrating dish with a sun tracking system implementing a control algorithm to maximize the capturing of solar energy. Further, it utilizes a patent developed by the authors where a mechanism is designed for the transmission of reciprocating motion of variable amplitude into unidirectional circular motion. This is employed in our prototype for converting linear reciprocating motion into circular for electricity production, which gives a significant increase in efficiency and reduces maintenance costs. Preliminary calculations indicate that the Heliotrope approach constitutes a competitive solution to solar power production.

Meteorological Support of the Helios World Record High Altitude Flight to 96,863 Feet

NASA Technical Reports Server (NTRS)

Teets, Edward H., Jr.; Donohue, Casey J.; Wright, Patrick T.; DelFrate, John (Technical Monitor)

2002-01-01

In characterizing and understanding atmospheric behavior when conducting high altitude solar powered flight research flight planning engineers and meteorologists are able to maximize the use of available airspace and coordinate aircraft maneuvers with pilots to make the best use of changing sun elevation angles. The result of this cooperative research produced a new world record for absolute altitude of a non-rocket powered aircraft of 96,863 ft (29,531.4 m). The Helios prototype solar powered aircraft, with a wingspan of 247 ft (75.0m), reached this altitude on August 13, 2001, off the coast of Kauai, Hawaii. The analyses of the weather characterization, the planning efforts, and the weather-of-the-day summary that led to at record flight are described in this paper.

Structural Analysis of Helios Filament-Wound Tanks Subjected to Internal Pressure and Cooling

NASA Technical Reports Server (NTRS)

Ko, William L

2005-01-01

A finite-element stress analysis is performed on Helios filament-wound hydrogen tanks to examine the stress field and effect of end dome geometry on the stress field. Each tank is composed of a central circular cylindrical section with either geodesic or hemispherical end domes, which have metallic polar bosses. The tanks are subjected to combined and separate internal pressure and temperature loading conditions, and the stress contributions of each loading component are examined. The tank-wall-polar-boss interfacial meridional tensile stress in the hemispherical dome is found to be approximately 27 percent lower than that in the geodesic dome. The effects of both material anisotropy and the aluminum lining on the intensities of tensile meridional stress at the tank-wall-polar-boss bonding interface are examined.

A curious fact: Photic sneeze reflex. Autosomical dominant compelling helio-ophthalmic outburst syndrome.

PubMed

Sevillano, C; Parafita-Fernández, A; Rodriguez-Lopez, V; Sampil, M; Moraña, N; Viso, E; Cores, F J

2016-07-01

To assess ocular involvement in the pathophysiology of autosomal dominant compelling helio-ophthalmic outburst syndrome (ACHOOs). An interview was conducted with a Caucasian family that showed clinical features of ACHOOs. Twelve of them had photic reflex and were recruited. A complete eye evaluation was made. A dominant autosomal inheritance with mild penetrance was demonstrated, with 67% of the studied subjects showing some degree of prominent corneal nerves. No other eye changes were found. Prominent corneal nerves may be associated with ACHOOs. The other eye structures studied do not seem to play a role in ACHOOs. Further studies are needed to understand the physiology of the ACHOOs. Copyright © 2016 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

Possible detection of flare-generated positrons by Helios 1 on 3 Jun 1982

NASA Technical Reports Server (NTRS)

Kirsch, E.; Keppler, E.; Richter, K.

1985-01-01

The production of neutrons and gamma-ray lines by solar particles in the photosphere has been studied. The principal positron emiters which lead to the 0.51 MeV gamma-line are C-11 0-14, 0-15, N-13, Ne-19. The energies of the positrons form radioactive nuclei are of the order of few hundred keV. Positrons resulting from the pi(+) decay have energies of approx 10-100 MeV and cannot be measured by the MPAe-detector. Most of the positrons annihilate in the photosphere. A fraction however should be able to escape into the interplanetary space. Proton, electron and , for the first time, positron measurements (E = 152-546 keV) obtained by the MPAe-particle detector on board of Helios 1 are presented.

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

Martin, William R.; Lee, John C.; baxter, Alan

Information and measured data from the intial Fort St. Vrain (FSV) high temperature gas reactor core is used to develop a benchmark configuration to validate computational methods for analysis of a full-core, commercial HTR configuration. Large uncertainties in the geometry and composition data for the FSV fuel and core are identified, including: (1) the relative numbers of fuel particles for the four particle types, (2) the distribution of fuel kernel diameters for the four particle types, (3) the Th:U ratio in the initial FSV core, (4) and the buffer thickness for the fissile and fertile particles. Sensitivity studies were performedmore » to assess each of these uncertainties. A number of methods were developed to assist in these studies, including: (1) the automation of MCNP5 input files for FSV using Python scripts, (2) a simple method to verify isotopic loadings in MCNP5 input files, (3) an automated procedure to conduct a coupled MCNP5-RELAP5 analysis for a full-core FSV configuration with thermal-hydraulic feedback, and (4) a methodology for sampling kernel diameters from arbitrary power law and Gaussian PDFs that preserved fuel loading and packing factor constraints. A reference FSV fuel configuration was developed based on having a single diameter kernel for each of the four particle types, preserving known uranium and thorium loadings and packing factor (58%). Three fuel models were developed, based on representing the fuel as a mixture of kernels with two diameters, four diameters, or a continuous range of diameters. The fuel particles were put into a fuel compact using either a lattice-bsed approach or a stochastic packing methodology from RPI, and simulated with MCNP5. The results of the sensitivity studies indicated that the uncertainties in the relative numbers and sizes of fissile and fertile kernels were not important nor were the distributions of kernel diameters within their diameter ranges. The uncertainty in the Th:U ratio in the intial FSV core was found to be important with a crude study. The uncertainty in the TRISO buffer thickness was estimated to be unimportant but the study was not conclusive. FSV fuel compacts and a regular FSV fuel element were analyzed with MCNP5 and compared with predictions using a modified version of HELIOS that is capable of analyzing TRISO fuel configurations. The HELIOS analyses were performed by SSP. The eigenvalue discrepancies between HELIOS and MCNP5 are currently on the order of 1% but these are still being evaluated. Full-core FSV configurations were developed for two initial critical configurations - a cold, clean critical loading and a critical configuration at 70% power. MCNP5 predictions are compared to experimental data and the results are mixed. Analyses were also done for the pulsed neutron experiments that were conducted by GA for the initial FSV core. MCNP5 was used to model these experiments and reasonable agreement with measured results has been observed.« less

New meteoroid model predictions for directional impacts on LDEF

NASA Technical Reports Server (NTRS)

Divine, Neil; Agueero, Rene C.

1993-01-01

An extensive body of data, from meteors, zodiacal light, spacecraft-borne impact detectors (Helios, Pioneer, Galileo, Ulysses), and other sources, forms the basis of a new numerical model for the distributions of interplanetary meteoroids. For each of the five populations in this model it is possible to evaluate meteoroid concentration and flux for oriented surfaces or detectors having arbitrary position and velocity in interplanetary space. For a spacecraft in geocentric orbit the effects of gravitational focussing and shielding by the Earth have been newly derived with full attention to the directionality of the particles, both on approach (i.e., relative to a massless Earth) and at the target. This modeling approach was exercised to provide an estimate of meteoroid fluence for each of several oriented surfaces on LDEF.

Intermittency in heavy ion collisions

NASA Astrophysics Data System (ADS)

Murray, Michael; HELIOS Collaboration

1991-04-01

This paper describes a study of multiplicity and transverse energy fluctuations using factorial moments for sulphur collisions with silver — bromide emulsion and platinium targets at 200 GeV/A. The data were taken with the HELIOS experiment at CERN. Bialas and Peschanski [1] predicted a power law dependence of the moments on the rapidity bin size if the fluctuations are invariant over a range of scales. This pattern is known as intermittency in the theory of turbulence, and indicates a fractal structure. Fluctuations were studied for a range of pseudorapidity scales using scaled factorial moments. Correlated fluctuations were studied using correlated scaled factorial moments. For peripheral collisions the data are weakly intermittent and consistent with a simple cascading mechanism, the a model. For central collisions no clear signal of intermittency was seen.

Intermittency in heavy ion collisions

NASA Astrophysics Data System (ADS)

1991-04-01

This paper describes a study of multiplicity and transverse energy fluctuations using factorial moments for sulphur collisions with silver - bromide emulsion and platinium targets at 200 GeV/A. The data were taken with the HELIOS experiment at CERN. Bialas and Peschanski [1] predicted a power law dependence of the moments on the rapidity bin size if the fluctuations are invariant over a range of scales. This pattern is known as intermittency in the theory of turbulence, and indicates a fractal structure. Fluctuations were studied for a range of pseudorapidity scales using scaled factorial moments. Correlated fluctuations were studied using correlated scaled factorial moments. For peripheral collisions the data are weakly intermittent and consistent with a simple cascading mechanism, the a model. For central collisions no clear signal of intermittency was seen.

Particle Physics Masterclass

ScienceCinema

Helio Takai

2017-12-09

Students from six local high schools -- Farmingdale, Sachem East, Shoreham, Smithtown East, Ward Melville, and William Floyd -- came to Brookhaven National Laboratory to experience research with particle physicist Helio Takai. They were among more than 6,

Validation of Direct Normal Irradiance from Meteosat Second Generation

NASA Astrophysics Data System (ADS)

Meyer, Angela; Stöckli, Reto; Vuilleumier, Laurent; Wilbert, Stefan; Zarzalejo, Luis

2016-04-01

We present a validation study of Direct Normal Irradiance (DNI) derived from MSG/SEVIRI radiance measurements over the site of Plataforma Solar de Almeria (PSA), a solar power plant in Southern Spain. The 1 km x 1 km site of PSA hosts about a dozen pyrheliometers operated by the German Aerospace Centre (DLR) and the Centre for Energy, Environment and Technological Research (CIEMAT). They provide high-quality long-term measurements of surface DNI on a site of the scale of the MSG/SEVIRI pixel resolution. This makes the PSA DNI measurements a dataset particularly well suited for satellite validation purposes. The satellite-based surface DNI was retrieved from MSG/SEVIRI radiances by the HelioMont algorithm (Stöckli 2013) that forms part of the Heliosat algorithm family (e.g. Müller et al., 2004). We have assessed the accuracy of this DNI product for the PSA site by comparing with the in-situ measured DNIs of June 2014 - July 2015. Despite a generally good agreement, the HelioMont DNI exhibits a significant low bias at the PSA site, that is most pronounced during clear-sky periods. We present a bias correction method and discuss (1) the role of circumsolar diffuse radiation and (2) the role of climatological vs. reanalysis-based aerosol optical properties therein. We also characterize and assess the temporal variability of the HelioMont DNI as compared to the in situ measured DNIs, and will discuss and quantify the uncertainties in both DNI datasets.

Parametric instability, inverse cascade and the range of solar-wind turbulence

NASA Astrophysics Data System (ADS)

Chandran, Benjamin D. G.

2018-02-01

In this paper, weak-turbulence theory is used to investigate the nonlinear evolution of the parametric instability in three-dimensional low- plasmas at wavelengths much greater than the ion inertial length under the assumption that slow magnetosonic waves are strongly damped. It is shown analytically that the parametric instability leads to an inverse cascade of Alfvén wave quanta, and several exact solutions to the wave kinetic equations are presented. The main results of the paper concern the parametric decay of Alfvén waves that initially satisfy +\\gg e-$ , where +$ and -$ are the frequency ( ) spectra of Alfvén waves propagating in opposite directions along the magnetic field lines. If +$ initially has a peak frequency 0$ (at which +$ is maximized) and an `infrared' scaling p$ at smaller with , then +$ acquires an -1$ scaling throughout a range of frequencies that spreads out in both directions from 0$ . At the same time, -$ acquires an -2$ scaling within this same frequency range. If the plasma parameters and infrared +$ spectrum are chosen to match conditions in the fast solar wind at a heliocentric distance of 0.3 astronomical units (AU), then the nonlinear evolution of the parametric instability leads to an +$ spectrum that matches fast-wind measurements from the Helios spacecraft at 0.3 AU, including the observed -1$ scaling at -4~\\text{Hz}$ . The results of this paper suggest that the -1$ spectrum seen by Helios in the fast solar wind at -4~\\text{Hz}$ is produced in situ by parametric decay and that the -1$ range of +$ extends over an increasingly narrow range of frequencies as decreases below 0.3 AU. This prediction will be tested by measurements from the Parker Solar Probe.

ED01-0146-1

NASA Image and Video Library

2001-04-28

Ground crewmen maneuver AeroVironment's solar-powered Helios Prototype flying wing on its ground support dolly during functional checkouts prior to its first flights under solar power from the U.S. Navy's Pacific Missile Range Facility on Kaua'i, Hawaii.

ED01-0146-6

NASA Image and Video Library

2001-04-28

Ground crewmen maneuver AeroVironment's solar-powered Helios Prototype flying wing on its ground support dolly during functional checkouts prior to its first flights under solar power from the U.S. Navy's Pacific Missile Range Facility on Kaua'i, Hawaii.

ED01-0146-5

NASA Image and Video Library

2001-04-28

Ground crewmen maneuver AeroVironment's solar-powered Helios Prototype flying wing on its ground support dolly during functional checkouts prior to its first flights under solar power from the U.S. Navy's Pacific Missile Range Facility on Kaua'i, Hawaii.

ED01-0146-2

NASA Image and Video Library

2001-04-28

Ground crewmen maneuver AeroVironment's solar-powered Helios Prototype flying wing on its ground support dolly during functional checkouts prior to its first flights under solar power from the U.S. Navy's Pacific Missile Range Facility on Kaua'i, Hawaii.

Distributed Software for Observations in the Near Infrared

NASA Astrophysics Data System (ADS)

Gavryusev, V.; Baffa, C.; Giani, E.

We have developed an integrated system that performs astronomical observations in Near Infrared bands operating two-dimensional instruments at the Italian National Infrared Facility's \\htmllink{ARNICA}{http://helios.arcetri.astro.it:/home/idefix/Mosaic/ instr/arnica/arnica.html} and \\htmllink{LONGSP}{http://helios.arcetri.astro.it:/home/idefix/Mosaic/ instr/longsp/longsp.html}. This software consists of several communicating processes, generally executed across a network, as well as on a single computer. The user interface is organized as widget-based X11 client. The interprocess communication is provided by sockets and uses TCP/IP. The processes denoted for control of hardware (telescope and other instruments) should be executed currently on a PC dedicated for this task under DESQview/X, while all other components (user interface, tools for the data analysis, etc.) can also work under UNIX\\@. The hardware independent part of software is based on the Athena Widget Set and is compiled by GNU C to provide maximum portability.

Solar wind helium ions - Observations of the Helios solar probes between 0.3 and 1 AU

NASA Technical Reports Server (NTRS)

Marsch, E.; Rosenbauer, H.; Schwenn, R.; Muehlhaeuser, K.-H.; Neubauer, F. M.

1982-01-01

A Helios solar probe survey of solar wind helium ion velocity distributions and derived parameters between 0.3 and 1 AU is presented. Distributions in high-speed wind are found to generally have small total anisotropies, with some indication that, in the core part, the temperatures are greater parallel rather than perpendicular to the magnetic field. The anisotropy tends to increase with heliocentric radial distance, and the average dependence of helium ion temperatures on radial distance from the sun is described by a power law. Differential ion speeds with values of more than 150 km/sec are observed near perihelion, or 0.3 AU. The role of Coulomb collisions in limiting differential ion speeds and the ion temperature ratio is investigated, and it is found that collisions play a distinct role in low-speed wind, by limiting both differential ion velocity and temperature.

EC02-0031-6

NASA Image and Video Library

2002-02-01

The Helios Prototype flying wing stretches almost the full length of the 300-foot-long hangar at NASA's Dryden Flight Research Center, Edwards, California. The 247-foot span solar-powered aircraft, resting on its ground maneuvering dolly, was on display for a visit of NASA Administrator Sean O'Keefe and other NASA officials on January 31, 2002. The unique solar-electric flying wing reached an altitude of 96,863 feet during an almost 17-hour flight near Hawaii on August 13, 2001, a world record for sustained horizontal flight by a non-rocket powered aircraft. Developed by AeroVironment, Inc., under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the Helios Prototype is the forerunner of a planned fleet of slow-flying, long duration, high-altitude uninhabited aerial vehicles (UAV) which can serve as "atmospheric satellites," performing Earth science missions or functioning as telecommunications relay platforms in the stratosphere.

EC02-0031-7

NASA Image and Video Library

2002-02-01

The solar-powered Helios Prototype flying wing frames two modified F-15 research aircraft in a hangar at NASA's Dryden Flight Research Center, Edwards, California. The elongated 247-foot span lightweight aircraft, resting on its ground maneuvering dolly, stretched almost the full length of the 300-foot long hangar while on display during a visit of NASA Administrator Sean O'Keefe and other NASA officials on Jan. 31, 2002. The unique solar-electric flying wing reached an altitude of 96,863 feet during an almost 17-hour flight near Hawaii on Aug. 13, 2001, a world record for sustained horizontal flight by a non-rocket powered aircraft. Developed by AeroVironment, Inc., under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the Helios Prototype is the forerunner of a planned fleet of slow-flying, long duration, high-altitude uninhabited aerial vehicles (UAV) which can serve as "atmospheric satellites," performing Earth science missions or functioning as telecommunications relay platforms in the stratosphere.

Synoptic maps constructed from brightness observations of Thomson scattering by heliospheric electrons

NASA Technical Reports Server (NTRS)

Hick, P.; Jackson, B.; Schwenn, R.

1991-01-01

Observations of the Thomson scattering brightness by electrons in the inner heliosphere provide a means of probing the heliospheric electron distributions. An extensive data base of Thomson scattering observations, stretching over many years, is available from the zodiacal light photometers on board the two Helios spacecraft. A survey of these data is in progress, presenting these scattering intensities in the form of synoptic maps for successive Carrington rotations. The Thomson scattering maps reflect conditions at typically several tenths of an astronomical unit from the sun. Some representative examples from the survey in comparison with other solar/heliospheric data, such as in situ observations of the Helios plasma experiment and synoptic maps constructed from magnetic field, H alpha and K-coronameter data are presented. The comparison will provide some information about the extension of solar surface features into the inner heliosphere.

Proton and electron mean free paths: The Palmer consensus revisited

NASA Technical Reports Server (NTRS)

Bieber, John W.; Matthaeus, William H.; Smith, Charles W.; Wanner, Wolfgang; Kallenrode, May-Britt; Wibberenz, Gerd

1994-01-01

We present experimental and theoretical evidence suggesting that the mean free path of cosmic-ray electrons and protons may be fundamentally different at low to intermediate (less than 50 MV) rigidities. The experimental evidence is from Helios observations of solar energetic particles, which show that the mean free path of 1.4 MV electrons is often similar to that of 187 MV protons, even though proton mean free paths continue to decrease comparatively rapidly with decreasing rigidty down to the lowest channels (about 100 MV) observed. The theoretical evidence is from computations of particle scattering in dynamical magnetic turbulence, which predict that electrons will have a larger mean free path than protons of the same rigidity. In the light of these new results, 'consensus' ideas about cosmic-ray mean free paths may require drastic revision.

New meteoroid model predictions for directional impacts on LDEF

NASA Technical Reports Server (NTRS)

Divine, Neil; Aguero, Rene C.

1992-01-01

An extensive body of data, from meteors, zodiacal light, spacecraft-borne impact detectors (helios, Pioneer, Galileo, and Ulysses), and other sources, forms the basis of a new numerical model for the distributions of interplanetary meteoroids. For each of the five populations in this model it is possible to evaluate meteoroid concentration and flux for oriented surfaces or detectors having arbitrary position and velocity in interplanetary space (Divine, 1992, in preparation). For a spacecraft in geocentric orbit, the effects of gravitational focusing and shielding by the Earth were derived with full attention to the directionality of the particles, both on approach (i.e., relative to a massless Earth) and at the target. This modeling approach was exercised to provide an estimate of meteoroid fluence for each of several oriented surfaces on the Long Duration Exposure Facility (LDEF).

A 1-D Study of the Ignition Space for Magnetic Indirect (X-ray) Drive Targets

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

Cobble, James Allen; Sinars, Daniel Brian

The ICF program today is investigating three approaches to achieving multi-MJ fusion yields and ignition: (1) laser indirect (x-ray) drive on the National Ignition Facility (NIF), (2) laser direct drive (primarily on the Omega laser facility at the University of Rochester), and (3) magnetic direct drive on the Z pulsed power facility. In this white paper we briefly consider a fourth approach, magnetic indirect drive, in which pulsedpower- driven x-ray sources are used in place of laser driven sources. We first look at some of the x-ray sources studied on Z prior to 2007 before the pulsed power ICF programmore » shifted to magnetic direct drive. We then show results from a series of 1D Helios calculations of double-shell capsules that suggest that these sources, scaled to higher temperatures, could be a promising path to achieving multi-MJ fusion yields and ignition. We advocate here that more detailed design calculations with widely accepted 2D/3D ICF codes should be conducted for a better assessment of the prospects.« less

Information computer program for laser therapy and laser puncture

NASA Astrophysics Data System (ADS)

Badovets, Nadegda N.; Medvedev, Andrei V.

1995-03-01

An informative computer program containing laser therapy and puncture methods has been developed. It was used successfully in connection with the compact Russian medical laser apparatus HELIOS-O1M in laser treatment and the education process.

The French thermo-helio-electricity-KW parabolic dish program

NASA Technical Reports Server (NTRS)

Audibert, M.; Peri, G.

1982-01-01

The testing and development of parabolic dish solar thermal power plants to produce, thermal mechanical, or electrical energy are discussed. The design, construction, and experiments of prototype collectors to prove the feasibility of such collectors is described.

ED01-0146-4

NASA Image and Video Library

2001-04-28

Helios Prototype crew chief Marshall MacCready of AeroVironment, Inc., carefully monitors motor runs during ground checkout of the solar-powered flying wing prior to its first flight from the U.S. Navy's Pacific Missile Range Facility on Kaua'i, Hawaii.

ED01-0146-3

NASA Image and Video Library

2001-04-28

The 247-foot length of the Helios prototype wing is in evidence as the high-altitude, solar-powered flying wing rests on its ground dolly during pre-flight tests at the U.S. Navy's Pacific Missile Range Facility on Kaua'i, Hawaii.

Effects of helium ion implantation on the surface morphology of tungsten at high temperature for the first wall armor and divertor plates of fusion reactors

NASA Astrophysics Data System (ADS)

Zenobia, Samuel J.

Three devices at the University of Wisconsin-Madison Inertial Electrostatic Confinement (UW IEC) laboratory were used to implant W and W alloys with helium ions at high temperatures. These devices were HOMER, HELIOS, and the Materials Irradiation Experiment (MITE-E). The research presented in this thesis will focus on the experiments carried out utilizing the MITE-E. Early UW work in HOMER and HELIOS on silicon carbide, carbon velvet, W-coated carbon velvet, fine-grain W, nano-grain W, W needles, and single- and polycrystalline W showed that these materials were not resistant to He+ implantation above ˜800 °C. Unalloyed W developed a "coral-like" surface morphology after He+ implantation, but appeared to be the most robust material investigated. The MITE-E used an ion gun technology to implant tungsten with 30 keV He+. Tungsten specimens were implanted at 900 °C to total average fluences of 6x1016 -- 6x1018 He +/cm2. Other specimens were implanted to a total average fluence of 5x1018 He+/cm2 at temperatures between 500 and 900 °C. Micrographs of the implanted W specimens revealed the development of three distinct surface morphologies. These morphologies are classified as "blistering", "pitting", and "orientated ridges". Preferential sputtering of the W by the energetic He+ appears to be responsible for pitting and orientated ridges which developed at high fluences (1019 He+/cm2) in the MITE-E. While the orientated ridges were the dominant morphology on the W surface above 700 °C, the pitting was prevalent below 700 °C. The blister morphology was observed at all of the examined temperatures at fluences ≥5x1017 He+/cm2 but disappeared above fluences of 1019 He+/cm 2. The "coral-like" surface morphology on W inherent to He + implantation experiments in HOMER and HELIOS developed from a combination of sources: multiangular ion incidence, ion energy spread (softening), and electron field emission from nano-scale surface features induced by He + implantation. The HOMER and HELIOS devices were found to be better suited for simulation of magnetic fusion environments with off-normal particle incidences, and the MITE-E was found to be more suited for simulating the normal particle incidence of inertial fusion environments.

Vector Adaptive/Predictive Encoding Of Speech

NASA Technical Reports Server (NTRS)

Chen, Juin-Hwey; Gersho, Allen

1989-01-01

Vector adaptive/predictive technique for digital encoding of speech signals yields decoded speech of very good quality after transmission at coding rate of 9.6 kb/s and of reasonably good quality at 4.8 kb/s. Requires 3 to 4 million multiplications and additions per second. Combines advantages of adaptive/predictive coding, and code-excited linear prediction, yielding speech of high quality but requires 600 million multiplications and additions per second at encoding rate of 4.8 kb/s. Vector adaptive/predictive coding technique bridges gaps in performance and complexity between adaptive/predictive coding and code-excited linear prediction.

EC03-0058-2

NASA Image and Video Library

2003-03-04

Aerovironment technicians carefully line up attachments as a fuel cell electrical system is installed on the Helios Prototype solar powered flying wing. The fuel cell system will power the aircraft at night during NASA-sponsored long-endurance demonstration flight in the summer of 2003.

Helio Moutinho | NREL

Science.gov Websites

length in single grains and the effect of grain boundaries in CdTe, and the effects of defects on the diffraction of CdTe thin films: Effects of CdCl2 treatment, J. Vac. Sci. Technol. A 26, 1068 (2008). H.R

Automatic Commercial Permit Sets

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

Grana, Paul

Final report for Folsom Labs’ Solar Permit Generator project, which has successfully completed, resulting in the development and commercialization of a software toolkit within the cloud-based HelioScope software environment that enables solar engineers to automatically generate and manage draft documents for permit submission.

High energy neutron and gamma-radiation generated during the solar flares

NASA Technical Reports Server (NTRS)

Kocharov, G. E.; Mandzhavidze, N. Z.

1985-01-01

The problem of high energy neutrons and gamma rays generation in the solar conditions is considered. It is shown that due to a peculiarity of generation and propagation of neutrons corresponding solar flares should be localized at high helio-longitudes.

CAD-Based Modeling of Advanced Rotary Wing Structures for Integrated 3-D Aeromechanics Analysis

NASA Astrophysics Data System (ADS)

Staruk, William

This dissertation describes the first comprehensive use of integrated 3-D aeromechanics modeling, defined as the coupling of 3-D solid finite element method (FEM) structural dynamics with 3-D computational fluid dynamics (CFD), for the analysis of a real helicopter rotor. The development of this new methodology (a departure from how rotor aeroelastic analysis has been performed for 40 years), its execution on a real rotor, and the fundamental understanding of aeromechanics gained from it, are the key contributions of this dissertation. This work also presents the first CFD/CSD analysis of a tiltrotor in edgewise flight, revealing many of its unique loading mechanisms. The use of 3-D FEM, integrated with a trim solver and aerodynamics modeling, has the potential to enhance the design of advanced rotors by overcoming fundamental limitations of current generation beam-based analysis tools and offering integrated internal dynamic stress and strain predictions for design. Two primary goals drove this research effort: 1) developing a methodology to create 3-D CAD-based brick finite element models of rotors including multibody joints, controls, and aerodynamic interfaces, and 2) refining X3D, the US Army's next generation rotor structural dynamics solver featuring 3-D FEM within a multibody formulation with integrated aerodynamics, to model a tiltrotor in the edgewise conversion flight regime, which drives critical proprotor structural loads. Prior tiltrotor analysis has primarily focused on hover aerodynamics with rigid blades or forward flight whirl-flutter stability with simplified aerodynamics. The first goal was met with the development of a detailed methodology for generating multibody 3-D structural models, starting from CAD geometry, continuing to higher-order hexahedral finite element meshing, to final assembly of the multibody model by creating joints, assigning material properties, and defining the aerodynamic interface. Several levels of verification and validation were carried out systematically, covering formulation, model accuracy, and accuracy of the physics of the problem and the many complex coupled aeromechanical phenomena that characterize the behavior of a tiltrotor in the conversion corridor. Compatibility of the new structural analysis models with X3D is demonstrated using analytical test cases, including 90° twisted beams and thick composite plates, and a notional bearingless rotor. Prediction of deformations and stresses in composite beams and plates is validated and verified against experimental measurements, theory, and state-of-the-art beam models. The second goal was met through integrated analysis of the Tilt Rotor Aeroacoustic Model (TRAM) proprotor using X3D coupled to Helios--the US Army's next generation CFD framework featuring a high fidelity Reynolds-average Navier-Stokes (RANS) structured/unstructured overset solver--as well as low order aerodynamic models. Although development of CFD was not part of this work, coupling X3D with Helios was, including establishing consistent interface definitions for blade deformations (for CFD mesh motion), aerodynamic interfaces (for loads transfer), and rotor control angles (for trim). It is expected that this method and solver will henceforth be an integral part of the Helios framework, providing an equal fidelity of representation for fluids and structures in the development of future advanced rotor systems. Structural dynamics analysis of the TRAM model show accurate prediction of the lower natural frequencies, demonstrating the ability to model advanced rotors from first principles using 3-D structural dynamics, and a study of how joint properties affect these frequencies reveals how X3D can be used as a detailed design tool. The CFD/CSD analysis reveals accurate prediction of rotor performance and airloads in edgewise flight when compared to wind tunnel test data. Structural blade loads trends are well predicted at low thrust, but a 3/rev component of flap and lag bending moment appearing in test data at high thrust remains a mystery. Efficiently simulating a gimbaled rotor is not trivial; a time-domain method with only a single blade model is proposed and tested. The internal stress in the blade, particularly at its root where the gimbal action has major influence, is carefully examined, revealing complex localized loading patterns.

T cell responses in senior patients with community-acquired pneumonia related to disease severity.

PubMed

Bian, Lu-Qin; Bi, Ying; Zhou, Shao-Wei; Chen, Zi-Dan; Wen, Jun; Shi, Jin; Mao, Ling; Wang, Ling

2017-12-01

Senior individuals older than 65 years of age are at a disproportionally higher risk of developing pneumonia. Impaired capacity to defend against airway infections may be one of the reasons. It is generally believed that weaker regulatory T cell responses may be beneficial to host defense against pathogens. In senior patients with community-acquired bacterial pneumonia, we investigated the frequencies and functions of regulatory T cells. Interestingly, we found that compared to age- and sex-matched healthy controls, senior pneumonia patients presented lower frequencies of Foxp3-expressing and Helios-expressing CD4 + T cells. The quantity of Foxp3 and Helios being expressed, measured by their mRNA transcription levels, was also lower in CD4 + T cells from pneumonia patients. Furthermore, following TCR and TGF-β stimulation, pneumonia patients presented impaired capacity to upregulate Foxp3 and Helios. Functional analyses revealed that CD4 + T cells from pneumonia patients secreted lower amounts of IL-10 and TGF-β, two cytokines critical to regulatory T cell-mediated suppression. Also, the expression of granzyme B and perforin, which were cytolytic molecules potentially utilized by regulatory T cells to mediate the elimination of antigen-presenting cells and effector T cells, were reduced in CD4 + CD25 + T cells from senior pneumonia patients. In addition, the CD4 + CD25 + T cells from senior pneumonia patients presented reduced capacity to suppress effector CD4 + and CD8 + T cell proliferation. Moreover, the value of pneumonia severity index was inversely correlated with several parameters of regulatory T cell function. Together, our results demonstrated that senior pneumonia patients presented a counterintuitive impairment in regulatory T cell responses that was associated with worse prognosis. Copyright © 2017 Elsevier Inc. All rights reserved.

Faraday rotation fluctutation spectra observed during solar occultation of the Helios spacecraft

NASA Technical Reports Server (NTRS)

Andreev, V.; Efimov, A. I.; Samoznaev, L.; Bird, M. K.

1995-01-01

Faraday rotation (FR) measurements using linearly polarized radio signals from the two Helios spacecraft were carried out during the period from 1975 to 1984. This paper presents the results of a spectral analysis of the Helios S-band FR fluctuations observed at heliocentric distances from 2.6 to 15 solar radii during the superior conjunctions 1975-1983. The mean intensity of the FR fluctuations does not exceed the noise level for solar offsets greater than ca. 15 solar radii. The rms FR fluctuation amplitude increases rapidly as the radio ray path approaches the Sun, varying according to a power law (exponent: 2.85 +/- 0.15) at solar distances 4-12 solar radii. At distances inside 4 solar radii the increase is even steeper (exponent: 5.6 +/- 0.2). The equivalent two-dimensional FR fluctuation spectrum is well modeled by a single power-law over the frequency range from 5 to 50 mHz. For heliocentric distances larger than 4 solar radii the spectral index varies between 1.1 and 1.6 with a mean value of 1.4 +/- 0.2, corresponding to a 3-D spectral index p = 2.4. FR fluctuations thus display a somwhat lower spectral index compared with phase and amplitude fluctuations. Surprisingly high values of the spectral index were found for measurements inside 4 solar radii (p = 2.9 +/- 0.2). This may arise from the increasingly dominant effect of the magnetic field on radio wave propagation at small solar offsets. Finally, a quasiperiodic component, believed to be associated with Alfven waves, was discovered in some (but not all!) fluctuation spectra observed simultaneously at two ground stations. Characteristic periods and bulk velocities of this component were 240 +/- 30 sec and 300 +/- 60 km/s, respectively.

Radial evolution of power spectra of interplanetary Alfvenic turbulence

NASA Technical Reports Server (NTRS)

Bavassano, B.; Dobrowolny, M.; Mariani, F.; Ness, N. F.

1981-01-01

The radial evolution of the power spectra of the MHD turbulence within the trailing edge of high speed streams in the solar wind was investigated with the magnetic field data of Helios 1 and 2 for heliocentric distance between 0.3 and 0.9 AU. In the analyzed frequency range (.00028 Hz to .0083 Hz) the computed spectra have, near the Earth, values of the spectral index close to that predicted for an incompressible hydromagnetic turbulence in a stationary state. Approaching the Sun the spectral slope remains unchanged for frequencies f or approximately .00 Hz, whereas at lower frequencies, a clear evolution toward a less steep fall off with frequency is found. The radial gradient of the power in Alfvenic fluctuations depends on frequency and it increases upon increasing frequency. For frequencies f or approximately .00 Hz, however, the radial gradient remains approximately the same. Possible theoretical implications of the observational features are discussed.

The Deep Space Network, volume 39

NASA Technical Reports Server (NTRS)

1977-01-01

The functions, facilities, and capabilities of the Deep Space Network and its support of the Pioneer, Helios, and Viking missions are described. Progress in tracking and data acquisition research and technology, network engineering and modifications, as well as hardware and software implementation and operations are reported.

Summary of high efficiency silicon solar cell meeting held at NASA-Lewis

NASA Technical Reports Server (NTRS)

Bernatowicz, D. T.

1975-01-01

Attempts made to raise the efficiency of solar cells for space use are reported. The Helios, violet, and non-reflective cells were studied and it was concluded that the maximum practical efficiency of silicon solar cells is between 17 and 20%.

An engineer at AeroVironment's Design Development Center inspects a set of silicon solar cells for p

NASA Technical Reports Server (NTRS)

2000-01-01

An engineer at AeroVironment's Design Development Center in Simi Valley, California, closely inspects a set of silicon solar cells for potential defects. The cells, fabricated by SunPower, Inc., of Sunnyvale, California, are among 64,000 solar cells which have been installed on the Helios Prototype solar-powered aircraft to provide power to its 14 electric motors and operating systems. Developed by AeroVironment under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the Helios Prototype is the forerunner of a planned fleet of slow-flying, long duration, high-altitude aircraft which can perform atmospheric science missions and serve as telecommunications relay platforms in the stratosphere. Target goals set by NASA for the giant 246-foot span flying wing include reaching and sustaining subsonic horizontal flight at 100,000 feet altitude in 2001, and sustained continuous flight for at least four days and nights in 2003 with the aid of a regenerative fuel cell-based energy storage system now in development.

Measurement of the inertial properties of the Helios F-1 spacecraft

NASA Technical Reports Server (NTRS)

Gayman, W. H.

1975-01-01

A gravity pendulum method of measuring lateral moments of inertia of large structures with an error of less than 1% is outlined. The method is based on the fact that in a physical pendulum with a knife-edge support the distance from the axis of rotation to the system center of gravity determines the minimal period of oscillation and is equal to the system centroidal radius of gyration. The method is applied to results of a test procedure in which the Helios F-1 spacecraft was placed in a roll fixture with crossed flexure pivots as elastic constraints and system oscillation measurements were made with each of a set of added moment-of-inertia increments. Equations of motion are derived with allowance for the effect of the finite pivot radius and an error analysis is carried out to find the criterion for maximum accuracy in determining the square of the centroidal radius of gyration. The test procedure allows all measurements to be made with the specimen in upright position.

The mean coronal magnetic field determined from Helios Faraday rotation measurements

NASA Technical Reports Server (NTRS)

Patzold, M.; Bird, M. K.; Volland, H.; Levy, G. S.; Seidel, B. L.; Stelzried, C. T.

1987-01-01

Coronal Faraday rotation of the linearly polarized carrier signals of the Helios spacecraft was recorded during the regularly occurring solar occultations over almost a complete solar cycle from 1975 to 1984. These measurements are used to determine the average strength and radial variation of the coronal magnetic field at solar minimum at solar distances from 3-10 solar radii, i.e., the range over which the complex fields at the coronal base are transformed into the interplanetary spiral. The mean coronal magnetic field in 1975-1976 was found to decrease with radial distance according to r exp-alpha, where alpha = 2.7 + or - 0.2. The mean field magnitude was 1.0 + or - 0.5 x 10 to the -5th tesla at a nominal solar distance of 5 solar radii. Possibly higher magnetic field strengths were indicated at solar maximum, but a lack of data prevented a statistical determination of the mean coronal field during this epoch.

Solar corona electron density distribution

NASA Astrophysics Data System (ADS)

Esposito, P. B.; Edenhofer, P.; Lueneburg, E.

1980-07-01

The paper discusses the three and one-half months of single-frequency time delay data which were acquired from the Helios 2 spacecraft around the time of its solar occultation. The excess time delay due to integrated effect of free electrons along the signal's ray path could be separated and modeled following the determination of the spacecraft trajectory. An average solar corona and equatorial electron density profile during solar minimum were deduced from the time delay measurements acquired within 5-60 solar radii of the sun. As a point of reference at 10 solar radii from the sun, an average electron density was 4500 el/cu cm. However, an asymmetry was found in the electron density as the ray path moved from the west to east solar limb. This may be related to the fact that during entry into occultation the heliographic latitude of the ray path was about 6 deg, while during exit it was 7 deg. The Helios density model is compared with similar models deduced from different experimental techniques.

With or without you: predictive coding and Bayesian inference in the brain

PubMed Central

Aitchison, Laurence; Lengyel, Máté

2018-01-01

Two theoretical ideas have emerged recently with the ambition to provide a unifying functional explanation of neural population coding and dynamics: predictive coding and Bayesian inference. Here, we describe the two theories and their combination into a single framework: Bayesian predictive coding. We clarify how the two theories can be distinguished, despite sharing core computational concepts and addressing an overlapping set of empirical phenomena. We argue that predictive coding is an algorithmic / representational motif that can serve several different computational goals of which Bayesian inference is but one. Conversely, while Bayesian inference can utilize predictive coding, it can also be realized by a variety of other representations. We critically evaluate the experimental evidence supporting Bayesian predictive coding and discuss how to test it more directly. PMID:28942084

NASA Dryden Flight Research Center

NASA Technical Reports Server (NTRS)

Navarro, Robert

2009-01-01

This DVD has several short videos showing some of the work that Dryden is involved in with experimental aircraft. These are: shots showing the Active AeroElastic Wing (AAW) loads calibration tests, AAW roll maneuvers, AAW flight control surface inputs, Helios flight, and takeoff, and Pathfinder takeoff, flight and landing.

A review of predictive coding algorithms.

PubMed

Spratling, M W

2017-03-01

Predictive coding is a leading theory of how the brain performs probabilistic inference. However, there are a number of distinct algorithms which are described by the term "predictive coding". This article provides a concise review of these different predictive coding algorithms, highlighting their similarities and differences. Five algorithms are covered: linear predictive coding which has a long and influential history in the signal processing literature; the first neuroscience-related application of predictive coding to explaining the function of the retina; and three versions of predictive coding that have been proposed to model cortical function. While all these algorithms aim to fit a generative model to sensory data, they differ in the type of generative model they employ, in the process used to optimise the fit between the model and sensory data, and in the way that they are related to neurobiology. Copyright © 2016 Elsevier Inc. All rights reserved.

Parametric Instability, Inverse Cascade, and the 1/f Range of Solar-Wind Turbulence.

PubMed

Chandran, Benjamin D G

2018-02-01

In this paper, weak turbulence theory is used to investigate the nonlinear evolution of the parametric instability in 3D low- β plasmas at wavelengths much greater than the ion inertial length under the assumption that slow magnetosonic waves are strongly damped. It is shown analytically that the parametric instability leads to an inverse cascade of Alfvén wave quanta, and several exact solutions to the wave kinetic equations are presented. The main results of the paper concern the parametric decay of Alfvén waves that initially satisfy e + ≫ e - , where e + and e - are the frequency ( f ) spectra of Alfvén waves propagating in opposite directions along the magnetic field lines. If e + initially has a peak frequency f 0 (at which fe + is maximized) and an "infrared" scaling f p at smaller f with -1 < p < 1, then e + acquires an f -1 scaling throughout a range of frequencies that spreads out in both directions from f 0 . At the same time, e - acquires an f -2 scaling within this same frequency range. If the plasma parameters and infrared e + spectrum are chosen to match conditions in the fast solar wind at a heliocentric distance of 0.3 astronomical units (AU), then the nonlinear evolution of the parametric instability leads to an e + spectrum that matches fast-wind measurements from the Helios spacecraft at 0.3 AU, including the observed f -1 scaling at f ≳ 3 × 10 -4 Hz. The results of this paper suggest that the f -1 spectrum seen by Helios in the fast solar wind at f ≳ 3 × 10 -4 Hz is produced in situ by parametric decay and that the f -1 range of e + extends over an increasingly narrow range of frequencies as r decreases below 0.3 AU. This prediction will be tested by measurements from the Parker Solar Probe .

EC03-0058-6

NASA Image and Video Library

2003-03-04

Technicians for AeroVironment, Inc., jack up a pressure tank to the wing of the Helios Prototype solar-electric flying wing. The tank carries pressurized hydrogen to fuel an experimental fuel cell system that powered the aircraft at night during an almost two-day long-endurance flight demonstration in the summer of 2003.

Enhancing Co-operation between Mainstream and Special Education. Thematic Group 9. Helios II Programme.

ERIC Educational Resources Information Center

European Agency for Development in Special Needs Education, Middelfart (Denmark).

This booklet discusses mainstream and special education interaction through the experiences and conclusions of a working group of persons with disabilities, parents, administrators, mainstream teachers, teachers in special education, therapists, and professionals in special needs from 10 European countries. It focuses upon the special needs…

Anatomy of a bearing torque problem

NASA Technical Reports Server (NTRS)

Phinney, Damon D.

1987-01-01

In the early 1970s, an antenna despin drive was developed for MBB solar science satellite HELIOS. A problem with high bearing drag torque that was encountered on the two flight models of this drive, after successful tests were completed on twelve bearings, an engineering model, and the qualification unit is discussed.

Parametric Study of the Effect of Burnable Poison Rods for PWR Burnup Credit

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

Wagner, J.C.

2001-09-28

The Interim Staff Guidance on burnup credit (ISG-8) issued by the United States Nuclear Regulatory Commission's (U.S. NRC) Spent Fuel Project Office recommends restricting the use of burnup credit to assemblies that have not used burnable absorbers. This recommended restriction eliminates a large portion of the currently discharged spent fuel assemblies from cask loading, and thus severely limits the practical usefulness of burnup credit. In the absence of readily available information on burnable poison rod (BPR) design specifications and usage in U.S. pressurized-water-reactors (PWRs), and the subsequent reactivity effect of BPR exposure on discharged spent nuclear fuel (SNF), NRC staffmore » has indicated a need for additional information in these areas. In response, this report presents a parametric study of the effect of BPR exposure on the reactivity of SNF for various BPR designs, fuel enrichments, and exposure conditions, and documents BPR design specifications. Trends in the reactivity effects of BPRs are established with infinite pin-cell and assembly array calculations with the SCALE and HELIOS code packages, respectively. Subsequently, the reactivity effects of BPRs for typical initial enrichment and burnup combinations are quantified based on three-dimensional (3-D) KENO V.a Monte Carlo calculations with a realistic rail-type cask designed for burnup credit. The calculations demonstrate that the positive reactivity effect due to BPR exposure increases nearly linearly with burnup and is dependent on the number, poison loading, and design of the BPRs and the initial fuel enrichment. Expected typical reactivity increases, based on one-cycle BPR exposure, were found to be less than 1% {Delta}k. Based on the presented analysis, guidance is offered on an appropriate approach for calculating bounding SNF isotopic data for assemblies exposed to BPRs. Although the analyses do not address the issue of validation of depletion methods for assembly designs with BPRs, they do demonstrate that the effect of BPRs is generally well behaved and that independent codes and cross-section libraries predict similar results. The report concludes with a discussion of the issues for consideration and recommendations for inclusion of SNF assemblies exposed to BPRs in criticality safety analyses using burnup credit for dry cask storage and transport.« less

Solar Wind Proton Temperature Anisotropy: Linear Theory and WIND/SWE Observations

NASA Technical Reports Server (NTRS)

Hellinger, P.; Travnicek, P.; Kasper, J. C.; Lazarus, A. J.

2006-01-01

We present a comparison between WIND/SWE observations (Kasper et al., 2006) of beta parallel to p and T perpendicular to p/T parallel to p (where beta parallel to p is the proton parallel beta and T perpendicular to p and T parallel to p are the perpendicular and parallel proton are the perpendicular and parallel proton temperatures, respectively; here parallel and perpendicular indicate directions with respect to the ambient magnetic field) and predictions of the Vlasov linear theory. In the slow solar wind, the observed proton temperature anisotropy seems to be constrained by oblique instabilities, by the mirror one and the oblique fire hose, contrary to the results of the linear theory which predicts a dominance of the proton cyclotron instability and the parallel fire hose. The fast solar wind core protons exhibit an anticorrelation between beta parallel to c and T perpendicular to c/T parallel to c (where beta parallel to c is the core proton parallel beta and T perpendicular to c and T parallel to c are the perpendicular and parallel core proton temperatures, respectively) similar to that observed in the HELIOS data (Marsch et al., 2004).

Assessment of Current Jet Noise Prediction Capabilities

NASA Technical Reports Server (NTRS)

Hunter, Craid A.; Bridges, James E.; Khavaran, Abbas

2008-01-01

An assessment was made of the capability of jet noise prediction codes over a broad range of jet flows, with the objective of quantifying current capabilities and identifying areas requiring future research investment. Three separate codes in NASA s possession, representative of two classes of jet noise prediction codes, were evaluated, one empirical and two statistical. The empirical code is the Stone Jet Noise Module (ST2JET) contained within the ANOPP aircraft noise prediction code. It is well documented, and represents the state of the art in semi-empirical acoustic prediction codes where virtual sources are attributed to various aspects of noise generation in each jet. These sources, in combination, predict the spectral directivity of a jet plume. A total of 258 jet noise cases were examined on the ST2JET code, each run requiring only fractions of a second to complete. Two statistical jet noise prediction codes were also evaluated, JeNo v1, and Jet3D. Fewer cases were run for the statistical prediction methods because they require substantially more resources, typically a Reynolds-Averaged Navier-Stokes solution of the jet, volume integration of the source statistical models over the entire plume, and a numerical solution of the governing propagation equation within the jet. In the evaluation process, substantial justification of experimental datasets used in the evaluations was made. In the end, none of the current codes can predict jet noise within experimental uncertainty. The empirical code came within 2dB on a 1/3 octave spectral basis for a wide range of flows. The statistical code Jet3D was within experimental uncertainty at broadside angles for hot supersonic jets, but errors in peak frequency and amplitude put it out of experimental uncertainty at cooler, lower speed conditions. Jet3D did not predict changes in directivity in the downstream angles. The statistical code JeNo,v1 was within experimental uncertainty predicting noise from cold subsonic jets at all angles, but did not predict changes with heating of the jet and did not account for directivity changes at supersonic conditions. Shortcomings addressed here give direction for future work relevant to the statistical-based prediction methods. A full report will be released as a chapter in a NASA publication assessing the state of the art in aircraft noise prediction.

Titan/Centaur D-1T TC-2, Helios A flight data report. [of space missions

NASA Technical Reports Server (NTRS)

1975-01-01

Background data of spacecraft launching and flight are presented. A system analysis of the space vehicles is included, specifically on: (1) electronic equipment, (2) hydraulic equipment, (3) telemetry, (4) propulsion systems, (5) software (computers), and (6) guidance. Spacecraft and launch vehicle configurations are shown and described.

The Heinz Electronic Library Interactive On-line System (HELIOS): An Update.

ERIC Educational Resources Information Center

Galloway, Edward A.; Michalek, Gabrielle V.

1998-01-01

Describes a project at Carnegie Mellon University libraries to convert the congressional papers of the late Senator John Heinz to digital format and to create an online system to search and retrieve these papers. Highlights include scanning, optical character recognition, and a search engine utilizing natural language processing. (Author/LRW)

The deep space network, volume 12

NASA Technical Reports Server (NTRS)

1972-01-01

Progress in the development of the DSN is reported along with TDA research and technology, network engineering, hardware, and software implementation. Included are descriptions of the DSN function and facilities, Helios mission support, Mariner Venus/Mercury 1973 mission support, Viking mission support, tracking and ground-based navigation, communications, network control and data processing, and deep space stations.

An Online Information Skills Tutorial

ERIC Educational Resources Information Center

Christensen, Joanne; Morgan, Fawn; Kinikin, Janae

2013-01-01

Looking for new way to teach high school students how to use the library and library resources? The HeLIOS (Hemingway Library Information Online Skills) tutorial, an online tool designed specifically for high school students, may be the answer. For the past two years, students at home, in classrooms, and at libraries throughout Utah have used…

Comparison of GLIMPS and HFAST Stirling engine code predictions with experimental data

NASA Technical Reports Server (NTRS)

Geng, Steven M.; Tew, Roy C.

1992-01-01

Predictions from GLIMPS and HFAST design codes are compared with experimental data for the RE-1000 and SPRE free piston Stirling engines. Engine performance and available power loss predictions are compared. Differences exist between GLIMPS and HFAST loss predictions. Both codes require engine specific calibration to bring predictions and experimental data into agreement.

AeroVironment Technician Marshall MacCready carefully lays a panel of solar cells into place on a wi

NASA Technical Reports Server (NTRS)

2000-01-01

Technician Marshall MacCready carefully lays a panel of solar cells into place on a wing section of the Helios Prototype flying wing at AeroVironment's Design Development Center in Simi Valley, California. More than 1,800 panels containing some 64,000 bi-facial cells, fabricated by SunPower, Inc., of Sunnyvale, California, have been installed on the solar-powered aircraft to provide electricity to its 14 motors and operating systems. Developed by AeroVironment under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the Helios Prototype is the forerunner of a planned fleet of slow-flying, long duration, high-altitude aircraft which can perform atmospheric science missions and serve as telecommunications relay platforms in the stratosphere. Target goals set by NASA for the giant 246-foot span flying wing include reaching and sustaining subsonic horizontal flight at 100,000 feet altitude in 2001, and sustained continuous flight for at least four days and nights above 50,000 feet altitude 2003 with the aid of a regenerative fuel cell-based energy storage system now being developed.

Helios 1 energetic particle observations of the solar gamma-ray/neutron flare events of 1982 June 3 and 1980 June 21

NASA Technical Reports Server (NTRS)

Mcdonald, F. B.; Van Hollebeke, M. A. I.

1985-01-01

The characteristics of the energetic particles associated with the solar gamma-ray/neutron flare events of June 3, 1982 and June 21, 1980 observed by the Goddard cosmic-ray experiment on Helios 1 (at heliocentric distances of 0.57 and 0.54 AU, respectively) differ in several important respects from typical sonar particle increases. In particular, the June 3, 1982 event has a proton energy spectrum which fits a remarkable flat power law in kinetic energy with a spectral index of 1.2, an electron/proton ratio of 1 at 4 MeV, and a small but well-defined precursor event that began some 3 hr before the impulsive flare increase. Similar energetic particle precursors were observed for the gamma-ray associated 1980 June 21 and June 7 flare events. At energies less than about 40 MeV, the particle onset time measured for the June 3, 1982 event is anomalous, suggesting that these lower energy particles may have been released at the sun about 1-2 minutes before the higher energy particles.

The average solar wind in the inner heliosphere: Structures and slow variations

NASA Technical Reports Server (NTRS)

Schwenn, R.

1983-01-01

Measurements from the HELIOS solar probes indicated that apart from solar activity related disturbances there exist two states of the solar wind which might result from basic differences in the acceleration process: the fast solar wind (v 600 kms(-)1) emanating from magnetically open regions in the solar corona and the "slow" solar wind (v 400 kms(-)1) correlated with the more active regions and its mainly closed magnetic structures. In a comprehensive study using all HELIOS data taken between 1974 and 1982 the average behavior of the basic plasma parameters were analyzed as functions of the solar wind speed. The long term variations of the solar wind parameters along the solar cycle were also determined and numerical estimates given. These modulations appear to be distinct though only minor. In agreement with earlier studies it was concluded that the major modulations are in the number and size of high speed streams and in the number of interplanetary shock waves caused by coronal transients. The latter ones usually cause huge deviations from the averages of all parameters.

THOR: an open-source exo-GCM

NASA Astrophysics Data System (ADS)

Grosheintz, Luc; Mendonça, João; Käppeli, Roger; Lukas Grimm, Simon; Mishra, Siddhartha; Heng, Kevin

2015-12-01

In this talk, I will present THOR, the first fully conservative, GPU-accelerated exo-GCM (general circulation model) on a nearly uniform, global grid that treats shocks and is non-hydrostatic. THOR will be freely available to the community as a standard tool.Unlike most GCMs THOR solves the full, non-hydrostatic Euler equations instead of the primitive equations. The equations are solved on a global three-dimensional icosahedral grid by a second order Finite Volume Method (FVM). Icosahedral grids are nearly uniform refinements of an icosahedron. We've implemented three different versions of this grid. FVM conserves the prognostic variables (density, momentum and energy) exactly and doesn't require a diffusion term (artificial viscosity) in the Euler equations to stabilize our solver. Historically FVM was designed to treat discontinuities correctly. Hence it excels at resolving shocks, including those present in hot exoplanetary atmospheres.Atmospheres are generally in near hydrostatic equilibrium. We therefore implement a well-balancing technique recently developed at the ETH Zurich. This well-balancing ensures that our FVM maintains hydrostatic equilibrium to machine precision. Better yet, it is able to resolve pressure perturbations from this equilibrium as small as one part in 100'000. It is important to realize that these perturbations are significantly smaller than the truncation error of the same scheme without well-balancing. If during the course of the simulation (due to forcing) the atmosphere becomes non-hydrostatic, our solver continues to function correctly.THOR just passed an important mile stone. We've implemented the explicit part of the solver. The explicit solver is useful to study instabilities or local problems on relatively short time scales. I'll show some nice properties of the explicit THOR. An explicit solver is not appropriate for climate study because the time step is limited by the sound speed. Therefore, we are working on the first fully implicit GCM. By ESS3, I hope to present results for the advection equation.THOR is part of the Exoclimes Simulation Platform (ESP), a set of open-source community codes for simulating and understanding the atmospheres of exoplanets. The ESP also includes tools for radiative transfer and retrieval (HELIOS), an opacity calculator (HELIOS-K), and a chemical kinetics solver (VULCAN). We expect to publicly release an initial version of THOR in 2016 on www.exoclime.org.

Empirical model for the electron density peak height disturbance in response to solar wind conditions

NASA Astrophysics Data System (ADS)

Blanch, E.; Altadill, D.

2009-04-01

Geomagnetic storms disturb the quiet behaviour of the ionosphere, its electron density and the electron density peak height, hmF2. Many works have been done to predict the variations of the electron density but few efforts have been dedicated to predict the variations the hmF2 under disturbed helio-geomagnetic conditions. We present the results of the analyses of the F2 layer peak height disturbances occurred during intense geomagnetic storms for one solar cycle. The results systematically show a significant peak height increase about 2 hours after the beginning of the main phase of the geomagnetic storm, independently of both the local time position of the station at the onset of the storm and the intensity of the storm. An additional uplift is observed in the post sunset sector. The duration of the uplift and the height increase are dependent of the intensity of the geomagnetic storm, the season and the local time position of the station at the onset of the storm. An empirical model has been developed to predict the electron density peak height disturbances in response to solar wind conditions and local time which can be used for nowcasting and forecasting the hmF2 disturbances for the middle latitude ionosphere. This being an important output for EURIPOS project operational purposes.

Low-delay predictive audio coding for the HIVITS HDTV codec

NASA Astrophysics Data System (ADS)

McParland, A. K.; Gilchrist, N. H. C.

1995-01-01

The status of work relating to predictive audio coding, as part of the European project on High Quality Video Telephone and HD(TV) Systems (HIVITS), is reported. The predictive coding algorithm is developed, along with six-channel audio coding and decoding hardware. Demonstrations of the audio codec operating in conjunction with the video codec, are given.

Overview of Recent Radiation Transport Code Comparisons for Space Applications

NASA Astrophysics Data System (ADS)

Townsend, Lawrence

Recent advances in radiation transport code development for space applications have resulted in various comparisons of code predictions for a variety of scenarios and codes. Comparisons among both Monte Carlo and deterministic codes have been made and published by vari-ous groups and collaborations, including comparisons involving, but not limited to HZETRN, HETC-HEDS, FLUKA, GEANT, PHITS, and MCNPX. In this work, an overview of recent code prediction inter-comparisons, including comparisons to available experimental data, is presented and discussed, with emphases on those areas of agreement and disagreement among the various code predictions and published data.

Bit selection using field drilling data and mathematical investigation

NASA Astrophysics Data System (ADS)

Momeni, M. S.; Ridha, S.; Hosseini, S. J.; Meyghani, B.; Emamian, S. S.

2018-03-01

A drilling process will not be complete without the usage of a drill bit. Therefore, bit selection is considered to be an important task in drilling optimization process. To select a bit is considered as an important issue in planning and designing a well. This is simply because the cost of drilling bit in total cost is quite high. Thus, to perform this task, aback propagation ANN Model is developed. This is done by training the model using several wells and it is done by the usage of drilling bit records from offset wells. In this project, two models are developed by the usage of the ANN. One is to find predicted IADC bit code and one is to find Predicted ROP. Stage 1 was to find the IADC bit code by using all the given filed data. The output is the Targeted IADC bit code. Stage 2 was to find the Predicted ROP values using the gained IADC bit code in Stage 1. Next is Stage 3 where the Predicted ROP value is used back again in the data set to gain Predicted IADC bit code value. The output is the Predicted IADC bit code. Thus, at the end, there are two models that give the Predicted ROP values and Predicted IADC bit code values.

Translations on Narcotics and Dangerous Drugs No. 305

DTIC Science & Technology

1977-06-17

Zuluaga, office clerk; Haidee de Ceballos Ruiz, delegate. Miguel Antonio Celin Gonzalez, cashier; Helio Celis Guarin , judge; Mario Cespedes...judge; Alberto Alvarez Zapata, assistant prison director; Tomas Amariz Perez , judge; Jose David Andrade Guzxan, court clerk; Hugo Andrade Pava, judge...Arbelaez Madrid, magistrate; Luis Jaime Arboleda de Angulo, judge; Augusto Arciniegas Perez , court clerk; Luis Ardila Quitian, court reporter

The Heinz Electronic Library Interactive Online System (HELIOS): Building a Digital Archive Using Imaging, OCR, and Natural Language Processing Technologies.

ERIC Educational Resources Information Center

Galloway, Edward A.; Michalek, Gabrielle V.

1995-01-01

Discusses the conversion project of the congressional papers of Senator John Heinz into digital format and the provision of electronic access to these papers by Carnegie Mellon University. Topics include collection background, project team structure, document processing, scanning, use of optical character recognition software, verification…

Concentrating Solar Power Projects - Helios II | Concentrating Solar Power

Science.gov Websites

(Ciudad Real) Owner(s): Caja Castilla La Mancha Corporación, S.A. (5%) Fundo de Capital de Risco Energias La Mancha Corporación, S.A. (5%) Fundo de Capital de Risco Energias Renováveis-Caixa Capital (5

EC00-0283-3

NASA Image and Video Library

2000-09-18

An engineer at AeroVironment's Design Development Center in Simi Valley, California, closely inspects a set of silicon solar cells for potential defects. The cells, fabricated by SunPower, Inc., of Sunnyvale, California, are among 64,000 solar cells which have been installed on the Helios Prototype solar-powered aircraft to provide power to its 14 electric motors and operating systems.

EC00-0283-9

NASA Image and Video Library

2000-09-18

A technician at AeroVironment's Design Development Center in Simi Valley, California, checks a panel of silicon solar cells for conductivity and voltage. The bi-facial cells, fabricated by SunPower, Inc., of Sunnyvale, California, are among 64,000 solar cells which have been installed on the Helios Prototype solar-powered aircraft to provide power to its 14 electric motors and operating systems.

Research in space physics at the University of Iowa

NASA Technical Reports Server (NTRS)

Vanallen, J. A.

1972-01-01

The research is reported for current projects. Topics discussed include: study and analysis of data from Explorer 40, 43, and small scientific satellites; and the planned missions for Helios, UK-4, Pioneer R and H, and Hawkeye satellites. The progress in the theoretical studies of electron density of the solar corona, spectrophotometry, and interferometry are also reported.

Comparison of Code Predictions to Test Measurements for Two Orifice Compensated Hydrostatic Bearings at High Reynolds Numbers

NASA Technical Reports Server (NTRS)

Keba, John E.

1996-01-01

Rotordynamic coefficients obtained from testing two different hydrostatic bearings are compared to values predicted by two different computer programs. The first set of test data is from a relatively long (L/D=1) orifice compensated hydrostatic bearing tested in water by Texas A&M University (TAMU Bearing No.9). The second bearing is a shorter (L/D=.37) bearing and was tested in a lower viscosity fluid by Rocketdyne Division of Rockwell (Rocketdyne 'Generic' Bearing) at similar rotating speeds and pressures. Computed predictions of bearing rotordynamic coefficients were obtained from the cylindrical seal code 'ICYL', one of the industrial seal codes developed for NASA-LeRC by Mechanical Technology Inc., and from the hydrodynamic bearing code 'HYDROPAD'. The comparison highlights the difference the bearing has on the accuracy of the predictions. The TAMU Bearing No. 9 test data is closely matched by the predictions obtained for the HYDROPAD code (except for added mass terms) whereas significant differences exist between the data from the Rocketdyne 'Generic' bearing the code predictions. The results suggest that some aspects of the fluid behavior in the shorter, higher Reynolds Number 'Generic' bearing may not be modeled accurately in the codes. The ICYL code predictions for flowrate and direct stiffness approximately equal those of HYDROPAD. Significant differences in cross-coupled stiffness and the damping terms were obtained relative to HYDROPAD and both sets of test data. Several observations are included concerning application of the ICYL code.

Theory of Mind: A Neural Prediction Problem

PubMed Central

Koster-Hale, Jorie; Saxe, Rebecca

2014-01-01

Predictive coding posits that neural systems make forward-looking predictions about incoming information. Neural signals contain information not about the currently perceived stimulus, but about the difference between the observed and the predicted stimulus. We propose to extend the predictive coding framework from high-level sensory processing to the more abstract domain of theory of mind; that is, to inferences about others’ goals, thoughts, and personalities. We review evidence that, across brain regions, neural responses to depictions of human behavior, from biological motion to trait descriptions, exhibit a key signature of predictive coding: reduced activity to predictable stimuli. We discuss how future experiments could distinguish predictive coding from alternative explanations of this response profile. This framework may provide an important new window on the neural computations underlying theory of mind. PMID:24012000

Prediction of plant lncRNA by ensemble machine learning classifiers.

PubMed

Simopoulos, Caitlin M A; Weretilnyk, Elizabeth A; Golding, G Brian

2018-05-02

In plants, long non-protein coding RNAs are believed to have essential roles in development and stress responses. However, relative to advances on discerning biological roles for long non-protein coding RNAs in animal systems, this RNA class in plants is largely understudied. With comparatively few validated plant long non-coding RNAs, research on this potentially critical class of RNA is hindered by a lack of appropriate prediction tools and databases. Supervised learning models trained on data sets of mostly non-validated, non-coding transcripts have been previously used to identify this enigmatic RNA class with applications largely focused on animal systems. Our approach uses a training set comprised only of empirically validated long non-protein coding RNAs from plant, animal, and viral sources to predict and rank candidate long non-protein coding gene products for future functional validation. Individual stochastic gradient boosting and random forest classifiers trained on only empirically validated long non-protein coding RNAs were constructed. In order to use the strengths of multiple classifiers, we combined multiple models into a single stacking meta-learner. This ensemble approach benefits from the diversity of several learners to effectively identify putative plant long non-coding RNAs from transcript sequence features. When the predicted genes identified by the ensemble classifier were compared to those listed in GreeNC, an established plant long non-coding RNA database, overlap for predicted genes from Arabidopsis thaliana, Oryza sativa and Eutrema salsugineum ranged from 51 to 83% with the highest agreement in Eutrema salsugineum. Most of the highest ranking predictions from Arabidopsis thaliana were annotated as potential natural antisense genes, pseudogenes, transposable elements, or simply computationally predicted hypothetical protein. Due to the nature of this tool, the model can be updated as new long non-protein coding transcripts are identified and functionally verified. This ensemble classifier is an accurate tool that can be used to rank long non-protein coding RNA predictions for use in conjunction with gene expression studies. Selection of plant transcripts with a high potential for regulatory roles as long non-protein coding RNAs will advance research in the elucidation of long non-protein coding RNA function.

Efficient temporal and interlayer parameter prediction for weighted prediction in scalable high efficiency video coding

NASA Astrophysics Data System (ADS)

Tsang, Sik-Ho; Chan, Yui-Lam; Siu, Wan-Chi

2017-01-01

Weighted prediction (WP) is an efficient video coding tool that was introduced since the establishment of the H.264/AVC video coding standard, for compensating the temporal illumination change in motion estimation and compensation. WP parameters, including a multiplicative weight and an additive offset for each reference frame, are required to be estimated and transmitted to the decoder by slice header. These parameters cause extra bits in the coded video bitstream. High efficiency video coding (HEVC) provides WP parameter prediction to reduce the overhead. Therefore, WP parameter prediction is crucial to research works or applications, which are related to WP. Prior art has been suggested to further improve the WP parameter prediction by implicit prediction of image characteristics and derivation of parameters. By exploiting both temporal and interlayer redundancies, we propose three WP parameter prediction algorithms, enhanced implicit WP parameter, enhanced direct WP parameter derivation, and interlayer WP parameter, to further improve the coding efficiency of HEVC. Results show that our proposed algorithms can achieve up to 5.83% and 5.23% bitrate reduction compared to the conventional scalable HEVC in the base layer for SNR scalability and 2× spatial scalability, respectively.

DRA/NASA/ONERA Collaboration on Icing Research. Part 2; Prediction of Airfoil Ice Accretion

NASA Technical Reports Server (NTRS)

Wright, William B.; Gent, R. W.; Guffond, Didier

1997-01-01

This report presents results from a joint study by DRA, NASA, and ONERA for the purpose of comparing, improving, and validating the aircraft icing computer codes developed by each agency. These codes are of three kinds: (1) water droplet trajectory prediction, (2) ice accretion modeling, and (3) transient electrothermal deicer analysis. In this joint study, the agencies compared their code predictions with each other and with experimental results. These comparison exercises were published in three technical reports, each with joint authorship. DRA published and had first authorship of Part 1 - Droplet Trajectory Calculations, NASA of Part 2 - Ice Accretion Prediction, and ONERA of Part 3 - Electrothermal Deicer Analysis. The results cover work done during the period from August 1986 to late 1991. As a result, all of the information in this report is dated. Where necessary, current information is provided to show the direction of current research. In this present report on ice accretion, each agency predicted ice shapes on two dimensional airfoils under icing conditions for which experimental ice shapes were available. In general, all three codes did a reasonable job of predicting the measured ice shapes. For any given experimental condition, one of the three codes predicted the general ice features (i.e., shape, impingement limits, mass of ice) somewhat better than did the other two. However, no single code consistently did better than the other two over the full range of conditions examined, which included rime, mixed, and glaze ice conditions. In several of the cases, DRA showed that the user's knowledge of icing can significantly improve the accuracy of the code prediction. Rime ice predictions were reasonably accurate and consistent among the codes, because droplets freeze on impact and the freezing model is simple. Glaze ice predictions were less accurate and less consistent among the codes, because the freezing model is more complex and is critically dependent upon unsubstantiated heat transfer and surface roughness models. Thus, heat transfer prediction methods used in the codes became the subject for a separate study in this report to compare predicted heat transfer coefficients with a limited experimental database of heat transfer coefficients for cylinders with simulated glaze and rime ice shapes. The codes did a good job of predicting heat transfer coefficients near the stagnation region of the ice shapes. But in the region of the ice horns, all three codes predicted heat transfer coefficients considerably higher than the measured values. An important conclusion of this study is that further research is needed to understand the finer detail of of the glaze ice accretion process and to develop improved glaze ice accretion models.

Flowfield Comparisons from Three Navier-Stokes Solvers for an Axisymmetric Separate Flow Jet

NASA Technical Reports Server (NTRS)

Koch, L. Danielle; Bridges, James; Khavaran, Abbas

2002-01-01

To meet new noise reduction goals, many concepts to enhance mixing in the exhaust jets of turbofan engines are being studied. Accurate steady state flowfield predictions from state-of-the-art computational fluid dynamics (CFD) solvers are needed as input to the latest noise prediction codes. The main intent of this paper was to ascertain that similar Navier-Stokes solvers run at different sites would yield comparable results for an axisymmetric two-stream nozzle case. Predictions from the WIND and the NPARC codes are compared to previously reported experimental data and results from the CRAFT Navier-Stokes solver. Similar k-epsilon turbulence models were employed in each solver, and identical computational grids were used. Agreement between experimental data and predictions from each code was generally good for mean values. All three codes underpredict the maximum value of turbulent kinetic energy. The predicted locations of the maximum turbulent kinetic energy were farther downstream than seen in the data. A grid study was conducted using the WIND code, and comments about convergence criteria and grid requirements for CFD solutions to be used as input for noise prediction computations are given. Additionally, noise predictions from the MGBK code, using the CFD results from the CRAFT code, NPARC, and WIND as input are compared to data.

Coding tools investigation for next generation video coding based on HEVC

NASA Astrophysics Data System (ADS)

Chen, Jianle; Chen, Ying; Karczewicz, Marta; Li, Xiang; Liu, Hongbin; Zhang, Li; Zhao, Xin

2015-09-01

The new state-of-the-art video coding standard, H.265/HEVC, has been finalized in 2013 and it achieves roughly 50% bit rate saving compared to its predecessor, H.264/MPEG-4 AVC. This paper provides the evidence that there is still potential for further coding efficiency improvements. A brief overview of HEVC is firstly given in the paper. Then, our improvements on each main module of HEVC are presented. For instance, the recursive quadtree block structure is extended to support larger coding unit and transform unit. The motion information prediction scheme is improved by advanced temporal motion vector prediction, which inherits the motion information of each small block within a large block from a temporal reference picture. Cross component prediction with linear prediction model improves intra prediction and overlapped block motion compensation improves the efficiency of inter prediction. Furthermore, coding of both intra and inter prediction residual is improved by adaptive multiple transform technique. Finally, in addition to deblocking filter and SAO, adaptive loop filter is applied to further enhance the reconstructed picture quality. This paper describes above-mentioned techniques in detail and evaluates their coding performance benefits based on the common test condition during HEVC development. The simulation results show that significant performance improvement over HEVC standard can be achieved, especially for the high resolution video materials.

Development and verification of NRC`s single-rod fuel performance codes FRAPCON-3 AND FRAPTRAN

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

Beyer, C.E.; Cunningham, M.E.; Lanning, D.D.

1998-03-01

The FRAPCON and FRAP-T code series, developed in the 1970s and early 1980s, are used by the US Nuclear Regulatory Commission (NRC) to predict fuel performance during steady-state and transient power conditions, respectively. Both code series are now being updated by Pacific Northwest National Laboratory to improve their predictive capabilities at high burnup levels. The newest versions of the codes are called FRAPCON-3 and FRAPTRAN. The updates to fuel property and behavior models are focusing on providing best estimate predictions under steady-state and fast transient power conditions up to extended fuel burnups (> 55 GWd/MTU). Both codes will be assessedmore » against a data base independent of the data base used for code benchmarking and an estimate of code predictive uncertainties will be made based on comparisons to the benchmark and independent data bases.« less

Influence of flowfield and vehicle parameters on engineering aerothermal methods

NASA Technical Reports Server (NTRS)

Wurster, Kathryn E.; Zoby, E. Vincent; Thompson, Richard A.

1989-01-01

The reliability and flexibility of three engineering codes used in the aerosphace industry (AEROHEAT, INCHES, and MINIVER) were investigated by comparing the results of these codes with Reentry F flight data and ground-test heat-transfer data for a range of cone angles, and with the predictions obtained using the detailed VSL3D code; the engineering solutions were also compared. In particular, the impact of several vehicle and flow-field parameters on the heat transfer and the capability of the engineering codes to predict these results were determined. It was found that entropy, pressure gradient, nose bluntness, gas chemistry, and angle of attack all affect heating levels. A comparison of the results of the three engineering codes with Reentry F flight data and with the predictions obtained of the VSL3D code showed a very good agreement in the regions of the applicability of the codes. It is emphasized that the parameters used in this study can significantly influence the actual heating levels and the prediction capability of a code.

The Cortical Organization of Speech Processing: Feedback Control and Predictive Coding the Context of a Dual-Stream Model

ERIC Educational Resources Information Center

Hickok, Gregory

2012-01-01

Speech recognition is an active process that involves some form of predictive coding. This statement is relatively uncontroversial. What is less clear is the source of the prediction. The dual-stream model of speech processing suggests that there are two possible sources of predictive coding in speech perception: the motor speech system and the…

A high temperature fatigue life prediction computer code based on the total strain version of StrainRange Partitioning (SRP)

NASA Technical Reports Server (NTRS)

Mcgaw, Michael A.; Saltsman, James F.

1993-01-01

A recently developed high-temperature fatigue life prediction computer code is presented and an example of its usage given. The code discussed is based on the Total Strain version of Strainrange Partitioning (TS-SRP). Included in this code are procedures for characterizing the creep-fatigue durability behavior of an alloy according to TS-SRP guidelines and predicting cyclic life for complex cycle types for both isothermal and thermomechanical conditions. A reasonably extensive materials properties database is included with the code.

Statistical Analysis of CFD Solutions from the Third AIAA Drag Prediction Workshop

NASA Technical Reports Server (NTRS)

Morrison, Joseph H.; Hemsch, Michael J.

2007-01-01

The first AIAA Drag Prediction Workshop, held in June 2001, evaluated the results from an extensive N-version test of a collection of Reynolds-Averaged Navier-Stokes CFD codes. The code-to-code scatter was more than an order of magnitude larger than desired for design and experimental validation of cruise conditions for a subsonic transport configuration. The second AIAA Drag Prediction Workshop, held in June 2003, emphasized the determination of installed pylon-nacelle drag increments and grid refinement studies. The code-to-code scatter was significantly reduced compared to the first DPW, but still larger than desired. However, grid refinement studies showed no significant improvement in code-to-code scatter with increasing grid refinement. The third Drag Prediction Workshop focused on the determination of installed side-of-body fairing drag increments and grid refinement studies for clean attached flow on wing alone configurations and for separated flow on the DLR-F6 subsonic transport model. This work evaluated the effect of grid refinement on the code-to-code scatter for the clean attached flow test cases and the separated flow test cases.

ED01-0209-1

NASA Image and Video Library

2001-07-14

The solar-electric Helios Prototype flying wing is shown moments after takeoff, beginning its first test flight on solar power from the U.S. Navy's Pacific Missile Range Facility on Kauai, Hawaii, July 14, 2001. The 18-hour flight was a functional checkout of the aircraft's systems and performance in preparation for an attempt to reach sustained flight at 100,000 feet altitude later this summer.

ED01-0209-3

NASA Image and Video Library

2001-07-14

The solar-electric Helios Prototype flying wing is shown over the Pacific Ocean during its first test flight on solar power from the U.S. Navy's Pacific Missile Range Facility on Kauai, Hawaii, July 14, 2001. The 18-hour flight was a functional checkout of the aircraft's systems and performance in preparation for an attempt to reach sustained flight at 100,000 feet altitude later this summer.

ED01-0209-2

NASA Image and Video Library

2001-07-14

The solar-electric Helios Prototype flying wing is shown over the Pacific Ocean during its first test flight on solar power from the U.S. Navy's Pacific Missile Range Facility on Kauai, Hawaii, July 14, 2001. The 18-hour flight was a functional checkout of the aircraft's systems and performance in preparation for an attempt to reach sustained flight at 100,000 feet altitude later this summer.

Gamma ray transients

NASA Technical Reports Server (NTRS)

Cline, Thomas L.

1987-01-01

The discovery of cosmic gamma ray bursts was made with systems designed at Los Alamos Laboratory for the detection of nuclear explosions beyond the atmosphere. HELIOS-2 was the first gamma ray burst instrument launched; its initial results in 1976, seemed to deepen the mystery around gamma ray transients. Interplanetary spacecraft data were reviewed in terms of explaining the behavior and source of the transients.

EC99-45140-12

NASA Image and Video Library

1999-08-18

The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at Dryden in late 1998. The craft has a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of its solar-powered Pathfinder flying wing, and longer than either the Boeing 747 jetliner or Lockheed C-5 transport aircraft.

EC99-45161-10

NASA Image and Video Library

1999-09-08

The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at Dryden in late 1998. The craft has a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of its solar-powered Pathfinder flying wing, and longer than either the Boeing 747 jetliner or Lockheed C-5 transport aircraft.

EC99-45140-2

NASA Image and Video Library

1999-08-18

The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at Dryden in late 1998. The craft has a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of its solar-powered Pathfinder flying wing, and longer than either the Boeing 747 jetliner or Lockheed C-5 transport aircraft.

EC99-45161-8

NASA Image and Video Library

1999-09-08

The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at Dryden in late 1998. The craft has a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of its solar-powered Pathfinder flying wing, and longer than either the Boeing 747 jetliner or Lockheed C-5 transport aircraft.

EC99-45161-9

NASA Image and Video Library

1999-09-08

The Helios Prototype is an enlarged version of the Centurion flying wing, which flew a series of test flights at Dryden in late 1998. The craft has a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of its solar-powered Pathfinder flying wing, and longer than either the Boeing 747 jetliner or Lockheed C-5 transport aircraft.

Development and manufacture of reactive-transfer-printed CIGS photovoltaic modules

NASA Astrophysics Data System (ADS)

Eldada, Louay; Sang, Baosheng; Lu, Dingyuan; Stanbery, Billy J.

2010-09-01

In recent years, thin-film photovoltaic (PV) companies started realizing their low manufacturing cost potential, and grabbing an increasingly larger market share from multicrystalline silicon companies. Copper Indium Gallium Selenide (CIGS) is the most promising thin-film PV material, having demonstrated the highest energy conversion efficiency in both cells and modules. However, most CIGS manufacturers still face the challenge of delivering a reliable and rapid manufacturing process that can scale effectively and deliver on the promise of this material system. HelioVolt has developed a reactive transfer process for CIGS absorber formation that has the benefits of good compositional control, high-quality CIGS grains, and a fast reaction. The reactive transfer process is a two stage CIGS fabrication method. Precursor films are deposited onto substrates and reusable print plates in the first stage, while in the second stage, the CIGS layer is formed by rapid heating with Se confinement. High quality CIGS films with large grains were produced on a full-scale manufacturing line, and resulted in high-efficiency large-form-factor modules. With 14% cell efficiency and 12% module efficiency, HelioVolt started to commercialize the process on its first production line with 20 MW nameplate capacity.

The Traceable Radiometry Underpinning Terrestrial and Helio Studies (TRUTHS) mission

NASA Astrophysics Data System (ADS)

Green, Paul D.; Fox, Nigel P.; Lobb, Daniel; Friend, Jonathan

2015-10-01

TRUTHS (Traceable Radiometry Underpinning Terrestrial- and Helio-Studies) is a proposed small satellite mission to enable a space-based climate observing system capable of delivering data of the quality needed to provide the information needed by policy makers to make robust mitigation and adaptation decisions. This is achieved by embedding trust and confidence in the data and derived information (tied to international standards) from both its own measurements and by upgrading the performance and interoperability of other EO platforms, such as the Sentinels by in-flight reference calibration. TRUTHS would provide measurements of incoming (total and spectrally resolved) and global reflected spectrally and spatially (50 m) solar radiation at the 0.3% uncertainty level. These fundamental climate data products can be convolved into the building blocks for many ECVs and EO applications as envisaged by the 2015 ESA science strategy; in a cost effective manner. We describe the scientific drivers for the TRUTHS mission and how the requirements for the climate benchmarking and cross-calibration reference sensor are both complementary and simply implemented, with a small additional complexity on top of heritage calibration schemes. The calibration scheme components and the route to SI-traceable Earth-reflected solar spectral radiance and solar spectral irradiance are described.

Publisher Correction: Discordant congenital Zika syndrome twins show differential in vitro viral susceptibility of neural progenitor cells.

PubMed

Caires-Júnior, Luiz Carlos; Goulart, Ernesto; Melo, Uirá Souto; Araujo, Bruno Henrique Silva; Alvizi, Lucas; Soares-Schanoski, Alessandra; de Oliveira, Danyllo Felipe; Kobayashi, Gerson Shigeru; Griesi-Oliveira, Karina; Musso, Camila Manso; Amaral, Murilo Sena; daSilva, Lucas Ferreira; Astray, Renato Mancini; Suárez-Patiño, Sandra Fernanda; Ventini, Daniella Cristina; da Silva, Sérgio Gomes; Yamamoto, Guilherme Lopes; Ezquina, Suzana; Naslavsky, Michel Satya; Telles-Silva, Kayque Alves; Weinmann, Karina; van der Linden, Vanessa; van der Linden, Helio; de Oliveira, João Ricardo Mendes; Arrais, Nivia Maria Rodrigues; Melo, Adriana; Figueiredo, Thalita; Santos, Silvana; Meira, Joanna Goes Castro; Passos, Saulo Duarte; de Almeida, Roque Pacheco; Bispo, Ana Jovina Barreto; Cavalheiro, Esper Abrão; Kalil, Jorge; Cunha-Neto, Edécio; Nakaya, Helder; Andreata-Santos, Robert; de Souza Ferreira, Luis Carlos; Verjovski-Almeida, Sergio; Ho, Paulo Lee; Passos-Bueno, Maria Rita; Zatz, Mayana

2018-03-13

The original PDF version of this Article contained errors in the spelling of Luiz Carlos Caires-Júnior, Uirá Souto Melo, Bruno Henrique Silva Araujo, Alessandra Soares-Schanoski, Murilo Sena Amaral, Kayque Alves Telles-Silva, Vanessa van der Linden, Helio van der Linden, João Ricardo Mendes de Oliveira, Nivia Maria Rodrigues Arrais, Joanna Goes Castro Meira, Ana Jovina Barreto Bispo, Esper Abrão Cavalheiro, and Robert Andreata-Santos, which were incorrectly given as Luiz Carlos de Caires Jr., UiráSouto Melo, Bruno Silva Henrique Araujo, Alessandra Soares Schanoski, MuriloSena Amaral, Kayque Telles Alves Silva, Vanessa Van der Linden, Helio Van der Linden, João Mendes Ricardo de Oliveira, Nivia Rodrigues Maria Arrais, Joanna Castro Goes Meira, Ana JovinaBarreto Bispo, EsperAbrão Cavalheiro, and Robert Andreata Santos. Furthermore, in both the PDF and HTML versions of the Article, the top panel of Fig. 3e was incorrectly labeled '10608-1' and should have been '10608-4', and financial support from CAPES and DECIT-MS was inadvertently omitted from the Acknowledgements section. These errors have now been corrected in both the PDF and HTML versions of the Article.

An MRI Scan of the nucleus

NASA Astrophysics Data System (ADS)

Hoffman, Calem

2017-09-01

In the pursuit of a global description of nuclei, extensive experimental studies on short-lived isotopes have provided a wealth of new empirical information. Such data has been used to test theoretical concepts and in the development of innovative ideas. More directly, a novel device at Argonne National Laboratory, the HELIcal Orbit Spectrometer (HELIOS), was focused on providing detailed single-particle information on the malleability of the nuclear magic numbers. Once thought as immovable pillars in nuclear structure, the shell-gaps in nuclei defining magic numbers of nucleons are now well-known to evolve as proton-to-neutron ratios change. And, determination of the underlying components of the nuclear force driving the evolution is at the forefront of nuclear structure research. Additionally, the HELIOS device mentioned above also carries its own aura being that it is formed by a decommissioned MRI solenoid magnet. In this talk recent highlights and advancements in our description of nuclear shell evolution will be the focus along with a few sidestepping comments on the life-cycle and interplay between basic research and the applications of nuclear physics. This material is based upon work supported by the U.S. Department of Energy, Office of Science, under Contract Number DE-AC02-06CH11357.

Helios: History and Anatomy of a Successful In-House Enterprise High-Throughput Screening and Profiling Data Analysis System.

PubMed

Gubler, Hanspeter; Clare, Nicholas; Galafassi, Laurent; Geissler, Uwe; Girod, Michel; Herr, Guy

2018-06-01

We describe the main characteristics of the Novartis Helios data analysis software system (Novartis, Basel, Switzerland) for plate-based screening and profiling assays, which was designed and built about 11 years ago. It has been in productive use for more than 10 years and is one of the important standard software applications running for a large user community at all Novartis Institutes for BioMedical Research sites globally. A high degree of automation is reached by embedding the data analysis capabilities into a software ecosystem that deals with the management of samples, plates, and result data files, including automated data loading. The application provides a series of analytical procedures, ranging from very simple to advanced, which can easily be assembled by users in very flexible ways. This also includes the automatic derivation of a large set of quality control (QC) characteristics at every step. Any of the raw, intermediate, and final results and QC-relevant quantities can be easily explored through linked visualizations. Links to global assay metadata management, data warehouses, and an electronic lab notebook system are in place. Automated transfer of relevant data to data warehouses and electronic lab notebook systems are also implemented.

New Measurements of Methyl Ethyl Ketone (MEK) Photolysis Rates and Their Relevance to Global Oxidative Capacity

NASA Astrophysics Data System (ADS)

Brewer, J.; Ravishankara, A. R.; Mellouki, A.; Fischer, E. V.; Kukui, A.; Véronique, D.; Ait-helal, W.; Leglise, J.; Ren, Y.

2017-12-01

Methyl ethyl ketone (MEK) is one of the most abundant ketones in the atmosphere. MEK can be emitted directly into the atmosphere from both anthropogenic and natural sources, and it is also formed during the gas-phase oxidation of volatile organic compounds (VOCs). MEK is lost via reaction with OH, photolysis and deposition to the surface. Similar to the other atmospheric ketones, the photolysis of MEK may represent a source of HOx (OH + HO2) radicals in the upper troposphere. The degradation of MEK also leads to the atmospheric formation of acetaldehyde and formaldehyde. This work presents a new analysis of the temperature dependence of MEK photolysis cross-sections and a quantification of MEK photolysis rates under surface pressures using the CNRS HELIOS outdoor atmospheric chamber (Chambre de simulation atmosphérique à irradiation naturelle d'Orléans; http://www.era-orleans.org/ERA-TOOLS/helios-project.html). Additionally, we use the GEOS-Chem 3-D CTM (version 10-01, www.geos-chem.org) to investigate the impact of these newly measured rates and cross-sections on the global distribution and seasonality of MEK, as well as its importance to the tropospheric oxidative capacity.

Attitude Dynamics, Stability, and Control of a Heliogyro Solar Sail

NASA Astrophysics Data System (ADS)

Pimienta-Penalver, Adonis Reinier

A heliogyro solar sail concept, dubbed `HELIOS', is proposed as an alternative to deep space missions without the need for on-board propellant. Although this type of solar sail has existed in concept for several decades, and some previous studies have investigated certain aspects of its operation, a significant amount of research is still needed to analyze the dynamic and control characteristics of the structure under the projected range of orbital conditions. This work presents an improvement upon the existing discrete-mass models of the heliogyro blade, and the extension of its application from a single membrane blade to a fully-coupled approximation of the dynamics of the HELIOS system with multiple spinning membrane blades around a central hub. The incorporation of structural stiffness and external forcing effects into the model is demonstrated to add a further degree of fidelity in simulating the stability properties of the system. Additionally, the approximated dynamics of multiple-blade heliogyro structures are examined under the effect of solar radiation pressure. Lastly, this study evaluates a control algorithm at each blade root to impose structural integrity and attitude control by coordinating well-known helicopter blade pitching profiles.

Statistical Analysis of the AIAA Drag Prediction Workshop CFD Solutions

NASA Technical Reports Server (NTRS)

Morrison, Joseph H.; Hemsch, Michael J.

2007-01-01

The first AIAA Drag Prediction Workshop (DPW), held in June 2001, evaluated the results from an extensive N-version test of a collection of Reynolds-Averaged Navier-Stokes CFD codes. The code-to-code scatter was more than an order of magnitude larger than desired for design and experimental validation of cruise conditions for a subsonic transport configuration. The second AIAA Drag Prediction Workshop, held in June 2003, emphasized the determination of installed pylon-nacelle drag increments and grid refinement studies. The code-to-code scatter was significantly reduced compared to the first DPW, but still larger than desired. However, grid refinement studies showed no significant improvement in code-to-code scatter with increasing grid refinement. The third AIAA Drag Prediction Workshop, held in June 2006, focused on the determination of installed side-of-body fairing drag increments and grid refinement studies for clean attached flow on wing alone configurations and for separated flow on the DLR-F6 subsonic transport model. This report compares the transonic cruise prediction results of the second and third workshops using statistical analysis.

Inter-view prediction of intra mode decision for high-efficiency video coding-based multiview video coding

NASA Astrophysics Data System (ADS)

da Silva, Thaísa Leal; Agostini, Luciano Volcan; da Silva Cruz, Luis A.

2014-05-01

Intra prediction is a very important tool in current video coding standards. High-efficiency video coding (HEVC) intra prediction presents relevant gains in encoding efficiency when compared to previous standards, but with a very important increase in the computational complexity since 33 directional angular modes must be evaluated. Motivated by this high complexity, this article presents a complexity reduction algorithm developed to reduce the HEVC intra mode decision complexity targeting multiview videos. The proposed algorithm presents an efficient fast intra prediction compliant with singleview and multiview video encoding. This fast solution defines a reduced subset of intra directions according to the video texture and it exploits the relationship between prediction units (PUs) of neighbor depth levels of the coding tree. This fast intra coding procedure is used to develop an inter-view prediction method, which exploits the relationship between the intra mode directions of adjacent views to further accelerate the intra prediction process in multiview video encoding applications. When compared to HEVC simulcast, our method achieves a complexity reduction of up to 47.77%, at the cost of an average BD-PSNR loss of 0.08 dB.

Transonic Drag Prediction on a DLR-F6 Transport Configuration Using Unstructured Grid Solvers

NASA Technical Reports Server (NTRS)

Lee-Rausch, E. M.; Frink, N. T.; Mavriplis, D. J.; Rausch, R. D.; Milholen, W. E.

2004-01-01

A second international AIAA Drag Prediction Workshop (DPW-II) was organized and held in Orlando Florida on June 21-22, 2003. The primary purpose was to inves- tigate the code-to-code uncertainty. address the sensitivity of the drag prediction to grid size and quantify the uncertainty in predicting nacelle/pylon drag increments at a transonic cruise condition. This paper presents an in-depth analysis of the DPW-II computational results from three state-of-the-art unstructured grid Navier-Stokes flow solvers exercised on similar families of tetrahedral grids. The flow solvers are USM3D - a tetrahedral cell-centered upwind solver. FUN3D - a tetrahedral node-centered upwind solver, and NSU3D - a general element node-centered central-differenced solver. For the wingbody, the total drag predicted for a constant-lift transonic cruise condition showed a decrease in code-to-code variation with grid refinement as expected. For the same flight condition, the wing/body/nacelle/pylon total drag and the nacelle/pylon drag increment predicted showed an increase in code-to-code variation with grid refinement. Although the range in total drag for the wingbody fine grids was only 5 counts, a code-to-code comparison of surface pressures and surface restricted streamlines indicated that the three solvers were not all converging to the same flow solutions- different shock locations and separation patterns were evident. Similarly, the wing/body/nacelle/pylon solutions did not appear to be converging to the same flow solutions. Overall, grid refinement did not consistently improve the correlation with experimental data for either the wingbody or the wing/body/nacelle pylon configuration. Although the absolute values of total drag predicted by two of the solvers for the medium and fine grids did not compare well with the experiment, the incremental drag predictions were within plus or minus 3 counts of the experimental data. The correlation with experimental incremental drag was not significantly changed by specifying transition. Although the sources of code-to-code variation in force and moment predictions for the three unstructured grid codes have not yet been identified, the current study reinforces the necessity of applying multiple codes to the same application to assess uncertainty.

Advanced turboprop noise prediction: Development of a code at NASA Langley based on recent theoretical results

NASA Technical Reports Server (NTRS)

Farassat, F.; Dunn, M. H.; Padula, S. L.

1986-01-01

The development of a high speed propeller noise prediction code at Langley Research Center is described. The code utilizes two recent acoustic formulations in the time domain for subsonic and supersonic sources. The structure and capabilities of the code are discussed. Grid size study for accuracy and speed of execution on a computer is also presented. The code is tested against an earlier Langley code. Considerable increase in accuracy and speed of execution are observed. Some examples of noise prediction of a high speed propeller for which acoustic test data are available are given. A brisk derivation of formulations used is given in an appendix.

CELFE/NASTRAN Code for the Analysis of Structures Subjected to High Velocity Impact

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1978-01-01

CELFE (Coupled Eulerian Lagrangian Finite Element)/NASTRAN Code three-dimensional finite element code has the capability for analyzing of structures subjected to high velocity impact. The local response is predicted by CELFE and, for large problems, the far-field impact response is predicted by NASTRAN. The coupling of the CELFE code with NASTRAN (CELFE/NASTRAN code) and the application of the code to selected three-dimensional high velocity impact problems are described.

Indexing sensory plasticity: Evidence for distinct Predictive Coding and Hebbian learning mechanisms in the cerebral cortex.

PubMed

Spriggs, M J; Sumner, R L; McMillan, R L; Moran, R J; Kirk, I J; Muthukumaraswamy, S D

2018-04-30

The Roving Mismatch Negativity (MMN), and Visual LTP paradigms are widely used as independent measures of sensory plasticity. However, the paradigms are built upon fundamentally different (and seemingly opposing) models of perceptual learning; namely, Predictive Coding (MMN) and Hebbian plasticity (LTP). The aim of the current study was to compare the generative mechanisms of the MMN and visual LTP, therefore assessing whether Predictive Coding and Hebbian mechanisms co-occur in the brain. Forty participants were presented with both paradigms during EEG recording. Consistent with Predictive Coding and Hebbian predictions, Dynamic Causal Modelling revealed that the generation of the MMN modulates forward and backward connections in the underlying network, while visual LTP only modulates forward connections. These results suggest that both Predictive Coding and Hebbian mechanisms are utilized by the brain under different task demands. This therefore indicates that both tasks provide unique insight into plasticity mechanisms, which has important implications for future studies of aberrant plasticity in clinical populations. Copyright © 2018 Elsevier Inc. All rights reserved.

Correlation approach to identify coding regions in DNA sequences

NASA Technical Reports Server (NTRS)

Ossadnik, S. M.; Buldyrev, S. V.; Goldberger, A. L.; Havlin, S.; Mantegna, R. N.; Peng, C. K.; Simons, M.; Stanley, H. E.

1994-01-01

Recently, it was observed that noncoding regions of DNA sequences possess long-range power-law correlations, whereas coding regions typically display only short-range correlations. We develop an algorithm based on this finding that enables investigators to perform a statistical analysis on long DNA sequences to locate possible coding regions. The algorithm is particularly successful in predicting the location of lengthy coding regions. For example, for the complete genome of yeast chromosome III (315,344 nucleotides), at least 82% of the predictions correspond to putative coding regions; the algorithm correctly identified all coding regions larger than 3000 nucleotides, 92% of coding regions between 2000 and 3000 nucleotides long, and 79% of coding regions between 1000 and 2000 nucleotides. The predictive ability of this new algorithm supports the claim that there is a fundamental difference in the correlation property between coding and noncoding sequences. This algorithm, which is not species-dependent, can be implemented with other techniques for rapidly and accurately locating relatively long coding regions in genomic sequences.

Calibration and comparison of the NASA Lewis free-piston Stirling engine model predictions with RE-1000 test data

NASA Technical Reports Server (NTRS)

Geng, Steven M.

1987-01-01

A free-piston Stirling engine performance code is being upgraded and validated at the NASA Lewis Research Center under an interagency agreement between the Department of Energy's Oak Ridge National Laboratory and NASA Lewis. Many modifications were made to the free-piston code in an attempt to decrease the calibration effort. A procedure was developed that made the code calibration process more systematic. Engine-specific calibration parameters are often used to bring predictions and experimental data into better agreement. The code was calibrated to a matrix of six experimental data points. Predictions of the calibrated free-piston code are compared with RE-1000 free-piston Stirling engine sensitivity test data taken at NASA Lewis. Reasonable agreement was obtained between the code prediction and the experimental data over a wide range of engine operating conditions.

Calibration and comparison of the NASA Lewis free-piston Stirling engine model predictions with RE-1000 test data

NASA Technical Reports Server (NTRS)

Geng, Steven M.

1987-01-01

A free-piston Stirling engine performance code is being upgraded and validated at the NASA Lewis Research Center under an interagency agreement between the Department of Energy's Oak Ridge National Laboratory and NASA Lewis. Many modifications were made to the free-piston code in an attempt to decrease the calibration effort. A procedure was developed that made the code calibration process more systematic. Engine-specific calibration parameters are often used to bring predictions and experimental data into better agreement. The code was calibrated to a matrix of six experimental data points. Predictions of the calibrated free-piston code are compared with RE-1000 free-piston Stirling engine sensitivity test data taken at NASA Lewis. Resonable agreement was obtained between the code predictions and the experimental data over a wide range of engine operating conditions.

Predictive codes of familiarity and context during the perceptual learning of facial identities

NASA Astrophysics Data System (ADS)

Apps, Matthew A. J.; Tsakiris, Manos

2013-11-01

Face recognition is a key component of successful social behaviour. However, the computational processes that underpin perceptual learning and recognition as faces transition from unfamiliar to familiar are poorly understood. In predictive coding, learning occurs through prediction errors that update stimulus familiarity, but recognition is a function of both stimulus and contextual familiarity. Here we show that behavioural responses on a two-option face recognition task can be predicted by the level of contextual and facial familiarity in a computational model derived from predictive-coding principles. Using fMRI, we show that activity in the superior temporal sulcus varies with the contextual familiarity in the model, whereas activity in the fusiform face area covaries with the prediction error parameter that updated facial familiarity. Our results characterize the key computations underpinning the perceptual learning of faces, highlighting that the functional properties of face-processing areas conform to the principles of predictive coding.

Prediction task guided representation learning of medical codes in EHR.

PubMed

Cui, Liwen; Xie, Xiaolei; Shen, Zuojun

2018-06-18

There have been rapidly growing applications using machine learning models for predictive analytics in Electronic Health Records (EHR) to improve the quality of hospital services and the efficiency of healthcare resource utilization. A fundamental and crucial step in developing such models is to convert medical codes in EHR to feature vectors. These medical codes are used to represent diagnoses or procedures. Their vector representations have a tremendous impact on the performance of machine learning models. Recently, some researchers have utilized representation learning methods from Natural Language Processing (NLP) to learn vector representations of medical codes. However, most previous approaches are unsupervised, i.e. the generation of medical code vectors is independent from prediction tasks. Thus, the obtained feature vectors may be inappropriate for a specific prediction task. Moreover, unsupervised methods often require a lot of samples to obtain reliable results, but most practical problems have very limited patient samples. In this paper, we develop a new method called Prediction Task Guided Health Record Aggregation (PTGHRA), which aggregates health records guided by prediction tasks, to construct training corpus for various representation learning models. Compared with unsupervised approaches, representation learning models integrated with PTGHRA yield a significant improvement in predictive capability of generated medical code vectors, especially for limited training samples. Copyright © 2018. Published by Elsevier Inc.

Helios Dynamics A Potential Future Power Source for the Greek Islands

DTIC Science & Technology

2007-06-01

offer an apparent understanding of the capabilities of the emerging Photovoltaic Power Converter (PVPC) technology used in panels for electricity... powering method that uses fueled generators and the alternative option is photovoltaic panels with the Atira technology embedded. This analysis is... POWER SOURCE FOR THE GREEK ISLANDS ABSTRACT The use of Alternative Renewable Energy Sources is becoming an increasing possibility to

Bi-directional streaming of halo electrons in interplanetary plasma clouds observed between 0.3 and 1 AU

NASA Technical Reports Server (NTRS)

Ivory, K.; Schwenn, R.

1995-01-01

The solar wind data obtained from the two Helios solar probes in the years 1974 to 1986 were systematically searched for the occurrence of bi-directional electron events. Most often these events are found in conjunction with shock associated magnetic clouds. The implications of these observations for the topology of interplanetary plasma clouds are discussed.

EC00-0283-4

NASA Image and Video Library

2000-09-18

Technician Marshall MacCready carefully lays a panel of solar cells into place on a wing section of the Helios Prototype flying wing at AeroVironment's Design Development Center in Simi Valley, California. The bi-facial cells, manufactured by SunPower, Inc., of Sunnyvale, California, are among 64,000 solar cells which have been installed on the solar-powered aircraft to provide electricity to its 14 motors and operating systems.

EC00-0283-5

NASA Image and Video Library

2000-09-18

Technician Marshall MacCready carefully lays a panel of solar cells into place on a wing section of the Helios Prototype flying wing at AeroVironment's Design Development Center in Simi Valley, California. More than 1,800 panels containing some 64,000 bi-facial cells, fabricated by SunPower, Inc., of Sunnyvale, California, have been installed on the solar-powered aircraft to provide electricity to its 14 motors and operating systems.

The deep space network, volume 13

NASA Technical Reports Server (NTRS)

1973-01-01

The objectives, functions, and organization of the Deep Space Network are summarized. The deep space instrumentation facility, the ground communications facility, and the network control system are described. Other areas reported include: Helios Mission support, DSN support of the Mariner Mars 1971 extended mission, Mariner Venus/Mercury 1973 mission support, Viking mission support, radio science, tracking and ground-based navigation, network control and data processing, and deep space stations.

ED01-0209-5

NASA Image and Video Library

2001-07-14

The solar-electric Helios Prototype flying wing is shown near the Hawaiian islands of Niihau and Lehua during its first test flight on solar power from the U.S. Navy's Pacific Missile Range Facility on Kauai, Hawaii, July 14, 2001. The 18-hour flight was a functional checkout of the aircraft's systems and performance in preparation for an attempt to reach sustained flight at 100,000 feet altitude later this summer.

ED01-0209-7

NASA Image and Video Library

2001-07-14

The solar-electric Helios Prototype flying wing is shown near the Hawaiian island of Niihau during its first test flight on solar power from the U.S. Navy's Pacific Missile Range Facility on Kauai, Hawaii, July 14, 2001. The 18-hour flight was a functional checkout of the aircraft's systems and performance in preparation for an attempt to reach sustained flight at 100,000 feet altitude later this summer.

ED01-0209-4

NASA Image and Video Library

2001-07-14

The solar-electric Helios Prototype flying wing is shown near the Hawaiian island of Niihau during its first test flight on solar power from the U.S. Navy's Pacific Missile Range Facility on Kauai, Hawaii, July 14, 2001. The 18-hour flight was a functional checkout of the aircraft's systems and performance in preparation for an attempt to reach sustained flight at 100,000 feet altitude later this summer.

ED01-0209-6

NASA Image and Video Library

2001-07-14

The solar-electric Helios Prototype flying wing is shown near the Hawaiian islands of Niihau and Lehua during its first test flight on solar power from the U.S. Navy's Pacific Missile Range Facility on Kauai, Hawaii, July 14, 2001. The 18-hour flight was a functional checkout of the aircraft's systems and performance in preparation for an attempt to reach sustained flight at 100,000 feet altitude later this summer.

Space Physics Cosmic & Heliospheric Data Evaluation Panel Report

NASA Technical Reports Server (NTRS)

McGuiere, R. E.; Cooper, J.; Gazis, P.; Kurth, W.; Lazarus, A.; McDonald, F.; McNutt, R.; Pyle, R.; Tsurutani, B. T.

1995-01-01

This Cosmic and Heliospheric (C&H) Data Evaluation Panel was charged with the task of identifying and prioritizing important C&H data sets. It was requested to provide C&H community input to the Space Physics Division for a program of revitalizing data holdings. Details and recommendations are provided. Highest C&H priority is assigned to Voyager, Pioneer, Helios, IMP-8, and ISEE-3 data.

78 FR 7466 - Notice of Applications for Deregistration Under Section 8(f) of the Investment Company Act of 1940

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-01

... declaring that it has ceased to be an investment company. The applicant has transferred its assets to Daily... Date: The application was filed on January 9, 2013. Applicant's Address: 7 Times Sq., 21st Floor, New.... The applicant has transferred its assets to Helios Total Return Fund Inc. and, on April 2, 2012, made...

Advanced Subsonic Technology (AST) Area of Interest (AOI) 6: Develop and Validate Aeroelastic Codes for Turbomachinery

NASA Technical Reports Server (NTRS)

Gardner, Kevin D.; Liu, Jong-Shang; Murthy, Durbha V.; Kruse, Marlin J.; James, Darrell

1999-01-01

AlliedSignal Engines, in cooperation with NASA GRC (National Aeronautics and Space Administration Glenn Research Center), completed an evaluation of recently-developed aeroelastic computer codes using test cases from the AlliedSignal Engines fan blisk and turbine databases. Test data included strain gage, performance, and steady-state pressure information obtained for conditions where synchronous or flutter vibratory conditions were found to occur. Aeroelastic codes evaluated included quasi 3-D UNSFLO (MIT Developed/AE Modified, Quasi 3-D Aeroelastic Computer Code), 2-D FREPS (NASA-Developed Forced Response Prediction System Aeroelastic Computer Code), and 3-D TURBO-AE (NASA/Mississippi State University Developed 3-D Aeroelastic Computer Code). Unsteady pressure predictions for the turbine test case were used to evaluate the forced response prediction capabilities of each of the three aeroelastic codes. Additionally, one of the fan flutter cases was evaluated using TURBO-AE. The UNSFLO and FREPS evaluation predictions showed good agreement with the experimental test data trends, but quantitative improvements are needed. UNSFLO over-predicted turbine blade response reductions, while FREPS under-predicted them. The inviscid TURBO-AE turbine analysis predicted no discernible blade response reduction, indicating the necessity of including viscous effects for this test case. For the TURBO-AE fan blisk test case, significant effort was expended getting the viscous version of the code to give converged steady flow solutions for the transonic flow conditions. Once converged, the steady solutions provided an excellent match with test data and the calibrated DAWES (AlliedSignal 3-D Viscous Steady Flow CFD Solver). However, efforts expended establishing quality steady-state solutions prevented exercising the unsteady portion of the TURBO-AE code during the present program. AlliedSignal recommends that unsteady pressure measurement data be obtained for both test cases examined for use in aeroelastic code validation.

Background-Modeling-Based Adaptive Prediction for Surveillance Video Coding.

PubMed

Zhang, Xianguo; Huang, Tiejun; Tian, Yonghong; Gao, Wen

2014-02-01

The exponential growth of surveillance videos presents an unprecedented challenge for high-efficiency surveillance video coding technology. Compared with the existing coding standards that were basically developed for generic videos, surveillance video coding should be designed to make the best use of the special characteristics of surveillance videos (e.g., relative static background). To do so, this paper first conducts two analyses on how to improve the background and foreground prediction efficiencies in surveillance video coding. Following the analysis results, we propose a background-modeling-based adaptive prediction (BMAP) method. In this method, all blocks to be encoded are firstly classified into three categories. Then, according to the category of each block, two novel inter predictions are selectively utilized, namely, the background reference prediction (BRP) that uses the background modeled from the original input frames as the long-term reference and the background difference prediction (BDP) that predicts the current data in the background difference domain. For background blocks, the BRP can effectively improve the prediction efficiency using the higher quality background as the reference; whereas for foreground-background-hybrid blocks, the BDP can provide a better reference after subtracting its background pixels. Experimental results show that the BMAP can achieve at least twice the compression ratio on surveillance videos as AVC (MPEG-4 Advanced Video Coding) high profile, yet with a slightly additional encoding complexity. Moreover, for the foreground coding performance, which is crucial to the subjective quality of moving objects in surveillance videos, BMAP also obtains remarkable gains over several state-of-the-art methods.

Predicting the Performance of an Axial-Flow Compressor

NASA Technical Reports Server (NTRS)

Steinke, R. J.

1986-01-01

Stage-stacking computer code (STGSTK) developed for predicting off-design performance of multi-stage axial-flow compressors. Code uses meanline stagestacking method. Stage and cumulative compressor performance calculated from representative meanline velocity diagrams located at rotor inlet and outlet meanline radii. Numerous options available within code. Code developed so user modify correlations to suit their needs.

Advanced turboprop noise prediction based on recent theoretical results

NASA Technical Reports Server (NTRS)

Farassat, F.; Padula, S. L.; Dunn, M. H.

1987-01-01

The development of a high speed propeller noise prediction code at Langley Research Center is described. The code utilizes two recent acoustic formulations in the time domain for subsonic and supersonic sources. The structure and capabilities of the code are discussed. Grid size study for accuracy and speed of execution on a computer is also presented. The code is tested against an earlier Langley code. Considerable increase in accuracy and speed of execution are observed. Some examples of noise prediction of a high speed propeller for which acoustic test data are available are given. A brisk derivation of formulations used is given in an appendix.

Comparison of Space Shuttle Hot Gas Manifold analysis to air flow data

NASA Technical Reports Server (NTRS)

Mcconnaughey, P. K.

1988-01-01

This paper summarizes several recent analyses of the Space Shuttle Main Engine Hot Gas Manifold and compares predicted flow environments to air flow data. Codes used in these analyses include INS3D, PAGE, PHOENICS, and VAST. Both laminar (Re = 250, M = 0.30) and turbulent (Re = 1.9 million, M = 0.30) results are discussed, with the latter being compared to data for system losses, outer wall static pressures, and manifold exit Mach number profiles. Comparison of predicted results for the turbulent case to air flow data shows that the analysis using INS3D predicted system losses within 1 percent error, while the PHOENICS, PAGE, and VAST codes erred by 31, 35, and 47 percent, respectively. The INS3D, PHOENICS, and PAGE codes did a reasonable job of predicting outer wall static pressure, while the PHOENICS code predicted exit Mach number profiles with acceptable accuracy. INS3D was approximately an order of magnitude more efficient than the other codes in terms of code speed and memory requirements. In general, it is seen that complex internal flows in manifold-like geometries can be predicted with a limited degree of confidence, and further development is necessary to improve both efficiency and accuracy of codes if they are to be used as design tools for complex three-dimensional geometries.

Light transport feature for SCINFUL.

PubMed

Etaati, G R; Ghal-Eh, N

2008-03-01

An extended version of the scintillator response function prediction code SCINFUL has been developed by incorporating PHOTRACK, a Monte Carlo light transport code. Comparisons of calculated and experimental results for organic scintillators exposed to neutrons show that the extended code improves the predictive capability of SCINFUL.

Dopamine reward prediction error coding.

PubMed

Schultz, Wolfram

2016-03-01

Reward prediction errors consist of the differences between received and predicted rewards. They are crucial for basic forms of learning about rewards and make us strive for more rewards-an evolutionary beneficial trait. Most dopamine neurons in the midbrain of humans, monkeys, and rodents signal a reward prediction error; they are activated by more reward than predicted (positive prediction error), remain at baseline activity for fully predicted rewards, and show depressed activity with less reward than predicted (negative prediction error). The dopamine signal increases nonlinearly with reward value and codes formal economic utility. Drugs of addiction generate, hijack, and amplify the dopamine reward signal and induce exaggerated, uncontrolled dopamine effects on neuronal plasticity. The striatum, amygdala, and frontal cortex also show reward prediction error coding, but only in subpopulations of neurons. Thus, the important concept of reward prediction errors is implemented in neuronal hardware.

Dopamine reward prediction error coding

PubMed Central

Schultz, Wolfram

2016-01-01

Reward prediction errors consist of the differences between received and predicted rewards. They are crucial for basic forms of learning about rewards and make us strive for more rewards—an evolutionary beneficial trait. Most dopamine neurons in the midbrain of humans, monkeys, and rodents signal a reward prediction error; they are activated by more reward than predicted (positive prediction error), remain at baseline activity for fully predicted rewards, and show depressed activity with less reward than predicted (negative prediction error). The dopamine signal increases nonlinearly with reward value and codes formal economic utility. Drugs of addiction generate, hijack, and amplify the dopamine reward signal and induce exaggerated, uncontrolled dopamine effects on neuronal plasticity. The striatum, amygdala, and frontal cortex also show reward prediction error coding, but only in subpopulations of neurons. Thus, the important concept of reward prediction errors is implemented in neuronal hardware. PMID:27069377

Characterizing the Properties of a Woven SiC/SiC Composite Using W-CEMCAN Computer Code

NASA Technical Reports Server (NTRS)

Murthy, Pappu L. N.; Mital, Subodh K.; DiCarlo, James A.

1999-01-01

A micromechanics based computer code to predict the thermal and mechanical properties of woven ceramic matrix composites (CMC) is developed. This computer code, W-CEMCAN (Woven CEramic Matrix Composites ANalyzer), predicts the properties of two-dimensional woven CMC at any temperature and takes into account various constituent geometries and volume fractions. This computer code is used to predict the thermal and mechanical properties of an advanced CMC composed of 0/90 five-harness (5 HS) Sylramic fiber which had been chemically vapor infiltrated (CVI) with boron nitride (BN) and SiC interphase coatings and melt-infiltrated (MI) with SiC. The predictions, based on the bulk constituent properties from the literature, are compared with measured experimental data. Based on the comparison. improved or calibrated properties for the constituent materials are then developed for use by material developers/designers. The computer code is then used to predict the properties of a composite with the same constituents but with different fiber volume fractions. The predictions are compared with measured data and a good agreement is achieved.

Centaur Standard Shroud (CSS) Heated Altitude Jettison Tests

NASA Technical Reports Server (NTRS)

1975-01-01

Altitude jettison tests, at a pressure of 20 torr (0.39 psia), were performed on the Centaur Standard Shroud (CSS) in a 100-foot diameter vacuum chamber. These jettison tests were part of a series of flight qualification tests which were performed on the new CSS system in preparation for the Helios and Viking missions. The first two tests subjected the CSS to a thermal cycle which simulated aerodynamic heating during ascent flight and the third test was performed at altitude pressure and in ambient temperature conditions. The purpose of the ambient temperature test was to provide base line data by which the separate machanical and thermal factors that influence jettison performance could be evaluated individually. The CSS was successfully jettisoned in each of the three tests. Also, thermal, stress, and structural deflection data were obtained which verified the analytical predictions of CSS response to flight environmental conditions and performance during jettison. In addition, much important information was obtained on critical CSS-to-payload clearance losses due to shell motions prior to and during jettison. The effectiveness of the separation system was successfully demonstrated at maximum flight temperatures.

Proton core-beam system in the expanding solar wind: Hybrid simulations

NASA Astrophysics Data System (ADS)

Hellinger, Petr; Trávníček, Pavel M.

2011-11-01

Results of a two-dimensional hybrid expanding box simulation of a proton beam-core system in the solar wind are presented. The expansion with a strictly radial magnetic field leads to a decrease of the ratio between the proton perpendicular and parallel temperatures as well as to an increase of the ratio between the beam-core differential velocity and the local Alfvén velocity creating a free energy for many different instabilities. The system is indeed most of the time marginally stable with respect to the parallel magnetosonic, oblique Alfvén, proton cyclotron and parallel fire hose instabilities which determine the system evolution counteracting some effects of the expansion and interacting with each other. Nonlinear evolution of these instabilities leads to large modifications of the proton velocity distribution function. The beam and core protons are slowed with respect to each other and heated, and at later stages of the evolution the two populations are not clearly distinguishable. On the macroscopic level the instabilities cause large departures from the double adiabatic prediction leading to an efficient isotropization of effective proton temperatures in agreement with Helios observations.

Use of the International Classification of Diseases, 9th revision, coding in identifying chronic hepatitis B virus infection in health system data: implications for national surveillance.

PubMed

Mahajan, Reena; Moorman, Anne C; Liu, Stephen J; Rupp, Loralee; Klevens, R Monina

2013-05-01

With increasing use electronic health records (EHR) in the USA, we looked at the predictive values of the International Classification of Diseases, 9th revision (ICD-9) coding system for surveillance of chronic hepatitis B virus (HBV) infection. The chronic HBV cohort from the Chronic Hepatitis Cohort Study was created based on electronic health records (EHR) of adult patients who accessed services from 2006 to 2008 from four healthcare systems in the USA. Using the gold standard of abstractor review to confirm HBV cases, we calculated the sensitivity, specificity, positive and negative predictive values using one qualifying ICD-9 code versus using two qualifying ICD-9 codes separated by 6 months or greater. Of 1 652 055 adult patients, 2202 (0.1%) were confirmed as having chronic HBV. Use of one ICD-9 code had a sensitivity of 83.9%, positive predictive value of 61.0%, and specificity and negative predictive values greater than 99%. Use of two hepatitis B-specific ICD-9 codes resulted in a sensitivity of 58.4% and a positive predictive value of 89.9%. Use of one or two hepatitis B ICD-9 codes can identify cases with chronic HBV infection with varying sensitivity and positive predictive values. As the USA increases the use of EHR, surveillance using ICD-9 codes may be reliable to determine the burden of chronic HBV infection and would be useful to improve reporting by state and local health departments.

Data integration of structured and unstructured sources for assigning clinical codes to patient stays

PubMed Central

Luyckx, Kim; Luyten, Léon; Daelemans, Walter; Van den Bulcke, Tim

2016-01-01

Objective Enormous amounts of healthcare data are becoming increasingly accessible through the large-scale adoption of electronic health records. In this work, structured and unstructured (textual) data are combined to assign clinical diagnostic and procedural codes (specifically ICD-9-CM) to patient stays. We investigate whether integrating these heterogeneous data types improves prediction strength compared to using the data types in isolation. Methods Two separate data integration approaches were evaluated. Early data integration combines features of several sources within a single model, and late data integration learns a separate model per data source and combines these predictions with a meta-learner. This is evaluated on data sources and clinical codes from a broad set of medical specialties. Results When compared with the best individual prediction source, late data integration leads to improvements in predictive power (eg, overall F-measure increased from 30.6% to 38.3% for International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnostic codes), while early data integration is less consistent. The predictive strength strongly differs between medical specialties, both for ICD-9-CM diagnostic and procedural codes. Discussion Structured data provides complementary information to unstructured data (and vice versa) for predicting ICD-9-CM codes. This can be captured most effectively by the proposed late data integration approach. Conclusions We demonstrated that models using multiple electronic health record data sources systematically outperform models using data sources in isolation in the task of predicting ICD-9-CM codes over a broad range of medical specialties. PMID:26316458

Software Design Strategies for Multidisciplinary Computational Fluid Dynamics

DTIC Science & Technology

2012-07-01

on the left-hand-side of Figure 3. The resulting unstructured grid system does a good job of representing the flowfield locally around the solid... Laboratory [16–19]. It uses Cartesian block structured grids, which lead to a substantially more efficient computational execution compared to the...including blade sectional lift and pitching moment. These Helios-computed airloads show good agreement with the experimental data. Many of the

Concentrating Solar Power Projects - Helios I | Concentrating Solar Power |

Science.gov Websites

Real) Owner(s): Caja Castilla La Mancha Corporación, S.A. (5%) Fundo de Capital de Risco Energias Country: Spain City: Puerto Lápice Region: Ciudad Real Lat/Long Location: 39°14' 24.0" North, 3°28 Start Production: June 2012 Construction Job-Years: 600 Annual O&M Jobs: 40 PPA/Tariff Type: Real

Election Verifiability: Cryptographic Definitions and an Analysis of Helios and JCJ

DTIC Science & Technology

2015-04-01

anonymous credentials. In CSF’14: 27th Computer Security Foundations Symposium. IEEE Computer Society, 2014. To appear. [22] David Chaum . Untraceable...electronic mail, return addresses, and digital pseudonyms. Communications of the ACM, 24(2):84–88, 1981. [23] David Chaum . Secret-ballot receipts...True voter-verifiable elections. IEEE Security and Privacy, 2(1):38–47, 2004. [24] David Chaum , Richard Carback, Jeremy Clark, Aleksander Essex, Stefan

Establishment of Models and Data Tracking for Small UAV Reliability

DTIC Science & Technology

2004-06-01

The development of solar powered UAVs is also being supported and funded by NASA. The idea, development, and construction was initiated by the...Aerovironment company, which has been involved in the construction of solar -powered aircraft for 20 years. Solar Challenger, HALSOL, Talon, Pathfinder...Centurion, and Helios with a wingspan of 247 feet, were among the solar -powered UAVs during those efforts.28 New technologies like regenerative fuel

The deep space network

NASA Technical Reports Server (NTRS)

1975-01-01

The objectives, functions, and organization of the Deep Space Network are summarized along with deep space station, ground communication, and network operations control capabilities. Mission support of ongoing planetary/interplanetary flight projects is discussed with emphasis on Viking orbiter radio frequency compatibility tests, the Pioneer Venus orbiter mission, and Helios-1 mission status and operations. Progress is also reported in tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations.

The Grog. A Journal of Navy Medical History and Culture. Issue 44

DTIC Science & Technology

2016-01-01

medical observation before being sent to sea. All Sailors would now have to undergo physical examination before being transferred or before they could...Wieber. carefully balanced rations, ventilation aboard ships, systematic physical ex- ercise, and general personal hygiene of all men in the Navy...cases helio (light) and occupational therapies . Below are some of the more notable sanitariums that still exist in the United States. Adirondack

The Deep Space Network

NASA Technical Reports Server (NTRS)

1974-01-01

The objectives, functions, and organization, of the Deep Space Network are summarized. Deep Space stations, ground communications, and network operations control capabilities are described. The network is designed for two-way communications with unmanned spacecraft traveling approximately 1600 km from earth to the farthest planets in the solar system. It has provided tracking and data acquisition support for the following projects: Ranger, Surveyor, Mariner, Pioneer, Apollo, Helios, Viking, and the Lunar Orbiter.

Two Moments of School Architecture in Sao Paulo: Ramos de Azevedo and His Republican Pioneering Schools/Helio Duarte and the "Educational Agreement"

ERIC Educational Resources Information Center

Lima, Ana Gabriela Godinho

2005-01-01

There are two peculiar moments in the history of the "struggle for national education", which, specifically in the city of Sao Paulo, capital of the State of Sao Paulo, one of the major and richest cities in Brazil, produced very interesting results in school architecture. The first moment happened in the period called the "First…

On the deficit problem of mass and energy of solar coronal mass ejections connected with interplanetary shocks

NASA Technical Reports Server (NTRS)

Ivanchuk, V. I.; Pishkalo, N. I.

1995-01-01

Mean values of a number of parameters of the most powerful coronal mass ejections (CMEs) and interplanetary shocks generated by these ejections are estimated using an analysis of data obtained by the cosmic coronagraphs and spacecrafts, and geomagnetic storm measurements. It was payed attention that the shock mass and mechanical energy, averaging 5 x 10(exp 16) grm and 2 x 10(exp 32) erg respectively, are nearly 10 times larger than corresponding parameters of the ejections. So, the CME energy deficit problem seems to exist really. To solve this problem one can make an assumption that the process of the mass and energy growth of CMEs during their propagation out of the Sun observed in the solar corona is continued in supercorona too up to distances of 10-30 solar radii. This assumption is confirmed by the data analysis of five events observed using zodiacal light photometers of the HELIOS- I and HELIOS-2 spacecrafts. The mass growth rate is estimated to be equal to (1-7) x 10(exp 11) grm/sec. It is concluded that the CME contribution to mass and energy flows in the solar winds probably, is larger enough than the value of 3-5% adopted usually.

Full parabolic trough qualification from prototype to demonstration loop

NASA Astrophysics Data System (ADS)

Janotte, Nicole; Lüpfert, Eckhard; Pottler, Klaus; Schmitz, Mark

2017-06-01

On the example of the HelioTrough® collector development the full accompanying and supporting qualification program for large-scale parabolic trough collectors for solar thermal power plants is described from prototype to demonstration loop scale. In the evaluation process the actual state and the optimization potential are assessed. This includes the optical and geometrical performance determined by concentrator shape, deformation, assembly quality and local intercept factor values. Furthermore, its mechanical performance in terms of tracking accuracy and torsional stiffness and its thermal system performance on the basis of the overall thermal output and heat loss are evaluated. Demonstration loop tests deliver results of collector modules statistical slope deviation of 1.9 to 2.6 mrad, intercept factor above 98%, peak optical performance of 81.6% and heat loss coefficients from field tests. The benefit of such a closely monitored development lies in prompt feedback on strengths, weaknesses and potential improvements on the new product at any development stage from first module tests until demonstration loop evaluation. The product developer takes advantage of the achieved technical maturity, already before the implementation in a commercial power plant. The well-understood performance characteristics allow the reduction of safety margins making the new HelioTrough collector competitive from the start.

Helio-geomagnetic influence in cardiological cases

NASA Astrophysics Data System (ADS)

Katsavrias, Ch.; Preka-Papadema, P.; Moussas, X.; Apostolou, Th.; Theodoropoulou, A.; Papadima, Th.

2013-01-01

The effects of the energetic phenomena of the Sun, flares and coronal mass ejections (CMEs) on the Earth's ionosphere-magnetosphere, through the solar wind, are the sources of the geomagnetic disturbances and storms collectively known as Space Weather. The research on the influence of Space Weather on biological and physiological systems is open. In this work we study the Space Weather impact on Acute Coronary Syndromes (ACS) distinguishing between ST-segment elevation acute coronary syndromes (STE-ACS) and non-ST-segment elevation acute coronary syndromes (NSTE-ACS) cases. We compare detailed patient records from the 2nd Cardiologic Department of the General Hospital of Nicaea (Piraeus, Greece) with characteristics of geomagnetic storms (DST), solar wind speed and statistics of flares and CMEs which cover the entire solar cycle 23 (1997-2007). Our results indicate a relationship of ACS to helio-geomagnetic activity as the maximum of the ACS cases follows closely the maximum of the solar cycle. Furthermore, within very active periods, the ratio NSTE-ACS to STE-ACS, which is almost constant during periods of low to medium activity, changes favouring the NSTE-ACS. Most of the ACS cases exhibit a high degree of association with the recovery phase of the geomagnetic storms; a smaller, yet significant, part was found associated with periods of fast solar wind without a storm.

Low-Density Parity-Check (LDPC) Codes Constructed from Protographs

NASA Astrophysics Data System (ADS)

Thorpe, J.

2003-08-01

We introduce a new class of low-density parity-check (LDPC) codes constructed from a template called a protograph. The protograph serves as a blueprint for constructing LDPC codes of arbitrary size whose performance can be predicted by analyzing the protograph. We apply standard density evolution techniques to predict the performance of large protograph codes. Finally, we use a randomized search algorithm to find good protographs.

High Speed Research Noise Prediction Code (HSRNOISE) User's and Theoretical Manual

NASA Technical Reports Server (NTRS)

Golub, Robert (Technical Monitor); Rawls, John W., Jr.; Yeager, Jessie C.

2004-01-01

This report describes a computer program, HSRNOISE, that predicts noise levels for a supersonic aircraft powered by mixed flow turbofan engines with rectangular mixer-ejector nozzles. It fully documents the noise prediction algorithms, provides instructions for executing the HSRNOISE code, and provides predicted noise levels for the High Speed Research (HSR) program Technology Concept (TC) aircraft. The component source noise prediction algorithms were developed jointly by Boeing, General Electric Aircraft Engines (GEAE), NASA and Pratt & Whitney during the course of the NASA HSR program. Modern Technologies Corporation developed an alternative mixer ejector jet noise prediction method under contract to GEAE that has also been incorporated into the HSRNOISE prediction code. Algorithms for determining propagation effects and calculating noise metrics were taken from the NASA Aircraft Noise Prediction Program.

Vibration Response Models of a Stiffened Aluminum Plate Excited by a Shaker

NASA Technical Reports Server (NTRS)

Cabell, Randolph H.

2008-01-01

Numerical models of structural-acoustic interactions are of interest to aircraft designers and the space program. This paper describes a comparison between two energy finite element codes, a statistical energy analysis code, a structural finite element code, and the experimentally measured response of a stiffened aluminum plate excited by a shaker. Different methods for modeling the stiffeners and the power input from the shaker are discussed. The results show that the energy codes (energy finite element and statistical energy analysis) accurately predicted the measured mean square velocity of the plate. In addition, predictions from an energy finite element code had the best spatial correlation with measured velocities. However, predictions from a considerably simpler, single subsystem, statistical energy analysis model also correlated well with the spatial velocity distribution. The results highlight a need for further work to understand the relationship between modeling assumptions and the prediction results.

Analysis of view synthesis prediction architectures in modern coding standards

NASA Astrophysics Data System (ADS)

Tian, Dong; Zou, Feng; Lee, Chris; Vetro, Anthony; Sun, Huifang

2013-09-01

Depth-based 3D formats are currently being developed as extensions to both AVC and HEVC standards. The availability of depth information facilitates the generation of intermediate views for advanced 3D applications and displays, and also enables more efficient coding of the multiview input data through view synthesis prediction techniques. This paper outlines several approaches that have been explored to realize view synthesis prediction in modern video coding standards such as AVC and HEVC. The benefits and drawbacks of various architectures are analyzed in terms of performance, complexity, and other design considerations. It is hence concluded that block-based VSP prediction for multiview video signals provides attractive coding gains with comparable complexity as traditional motion/disparity compensation.

Ex-Vessel Core Melt Modeling Comparison between MELTSPREAD-CORQUENCH and MELCOR 2.1

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

Robb, Kevin R.; Farmer, Mitchell; Francis, Matthew W.

System-level code analyses by both United States and international researchers predict major core melting, bottom head failure, and corium-concrete interaction for Fukushima Daiichi Unit 1 (1F1). Although system codes such as MELCOR and MAAP are capable of capturing a wide range of accident phenomena, they currently do not contain detailed models for evaluating some ex-vessel core melt behavior. However, specialized codes containing more detailed modeling are available for melt spreading such as MELTSPREAD as well as long-term molten corium-concrete interaction (MCCI) and debris coolability such as CORQUENCH. In a preceding study, Enhanced Ex-Vessel Analysis for Fukushima Daiichi Unit 1: Meltmore » Spreading and Core-Concrete Interaction Analyses with MELTSPREAD and CORQUENCH, the MELTSPREAD-CORQUENCH codes predicted the 1F1 core melt readily cooled in contrast to predictions by MELCOR. The user community has taken notice and is in the process of updating their systems codes; specifically MAAP and MELCOR, to improve and reduce conservatism in their ex-vessel core melt models. This report investigates why the MELCOR v2.1 code, compared to the MELTSPREAD and CORQUENCH 3.03 codes, yield differing predictions of ex-vessel melt progression. To accomplish this, the differences in the treatment of the ex-vessel melt with respect to melt spreading and long-term coolability are examined. The differences in modeling approaches are summarized, and a comparison of example code predictions is provided.« less

Tiltrotor Aeroacoustic Code (TRAC) Prediction Assessment and Initial Comparisons with Tram Test Data

NASA Technical Reports Server (NTRS)

Burley, Casey L.; Brooks, Thomas F.; Charles, Bruce D.; McCluer, Megan

1999-01-01

A prediction sensitivity assessment to inputs and blade modeling is presented for the TiltRotor Aeroacoustic Code (TRAC). For this study, the non-CFD prediction system option in TRAC is used. Here, the comprehensive rotorcraft code, CAMRAD.Mod1, coupled with the high-resolution sectional loads code HIRES, predicts unsteady blade loads to be used in the noise prediction code WOPWOP. The sensitivity of the predicted blade motions, blade airloads, wake geometry, and acoustics is examined with respect to rotor rpm, blade twist and chord, and to blade dynamic modeling. To accomplish this assessment, an interim input-deck for the TRAM test model and an input-deck for a reference test model are utilized in both rigid and elastic modes. Both of these test models are regarded as near scale models of the V-22 proprotor (tiltrotor). With basic TRAC sensitivities established, initial TRAC predictions are compared to results of an extensive test of an isolated model proprotor. The test was that of the TiltRotor Aeroacoustic Model (TRAM) conducted in the Duits-Nederlandse Windtunnel (DNW). Predictions are compared to measured noise for the proprotor operating over an extensive range of conditions. The variation of predictions demonstrates the great care that must be taken in defining the blade motion. However, even with this variability, the predictions using the different blade modeling successfully capture (bracket) the levels and trends of the noise for conditions ranging from descent to ascent.

Tiltrotor Aeroacoustic Code (TRAC) Prediction Assessment and Initial Comparisons With TRAM Test Data

NASA Technical Reports Server (NTRS)

Burley, Casey L.; Brooks, Thomas F.; Charles, Bruce D.; McCluer, Megan

1999-01-01

A prediction sensitivity assessment to inputs and blade modeling is presented for the TiltRotor Aeroacoustic Code (TRAC). For this study, the non-CFD prediction system option in TRAC is used. Here, the comprehensive rotorcraft code, CAMRAD.Mod 1, coupled with the high-resolution sectional loads code HIRES, predicts unsteady blade loads to be used in the noise prediction code WOPWOP. The sensitivity of the predicted blade motions, blade airloads, wake geometry, and acoustics is examined with respect to rotor rpm, blade twist and chord, and to blade dynamic modeling. To accomplish this assessment. an interim input-deck for the TRAM test model and an input-deck for a reference test model are utilized in both rigid and elastic modes. Both of these test models are regarded as near scale models of the V-22 proprotor (tiltrotor). With basic TRAC sensitivities established, initial TRAC predictions are compared to results of an extensive test of an isolated model proprotor. The test was that of the TiltRotor Aeroacoustic Model (TRAM) conducted in the Duits-Nederlandse Windtunnel (DNW). Predictions are compared to measured noise for the proprotor operating over an extensive range of conditions. The variation of predictions demonstrates the great care that must be taken in defining the blade motion. However, even with this variability, the predictions using the different blade modeling successfully capture (bracket) the levels and trends of the noise for conditions ranging from descent to ascent.

Monitoring Cosmic Radiation Risk: Comparisons between Observations and Predictive Codes for Naval Aviation

DTIC Science & Technology

2009-01-01

proton PARMA PHITS -based Analytical Radiation Model in the Atmosphere PCAIRE Predictive Code for Aircrew Radiation Exposure PHITS Particle and...radiation transport code utilized is called PARMA ( PHITS based Analytical Radiation Model in the Atmosphere) [36]. The particle fluxes calculated from the...same dose equivalent coefficient regulations from the ICRP-60 regulations. As a result, the transport codes utilized by EXPACS ( PHITS ) and CARI-6

Monitoring Cosmic Radiation Risk: Comparisons Between Observations and Predictive Codes for Naval Aviation

DTIC Science & Technology

2009-07-05

proton PARMA PHITS -based Analytical Radiation Model in the Atmosphere PCAIRE Predictive Code for Aircrew Radiation Exposure PHITS Particle and Heavy...transport code utilized is called PARMA ( PHITS based Analytical Radiation Model in the Atmosphere) [36]. The particle fluxes calculated from the input...dose equivalent coefficient regulations from the ICRP-60 regulations. As a result, the transport codes utilized by EXPACS ( PHITS ) and CARI-6 (PARMA

Centurion on Lakebed during Functional Checkout

NASA Technical Reports Server (NTRS)

1998-01-01

A close-up view of the 14 wide-bladed propellers and electric motors on the Centurion solar-powered, remotely piloted flying wing. This photo was taken during a functional checkout of the aircraft prior to its first test flights at NASA's Dryden Flight Research Center, Edwards, California, in late 1998. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Centurion in Flight with Internal Wing Structure Visible

NASA Technical Reports Server (NTRS)

1998-01-01

The lightweight wing structure and covering of the Centurion remotely piloted flying wing can be clearly seen in this photo of the plane during one of its initial low-altitude, battery-powered test flights in late 1998 at NASA's Dryden Flight Research Center, Edwards, California. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Centurion Quarter-scale Prototype Pre-flight Taxi Test

NASA Technical Reports Server (NTRS)

1997-01-01

As crewmen jog and cycle alongside, a battery-powered, quarter-scale prototype of the remotely-piloted Centurion flying wing rolls across the El Mirage Dry Lake during pre-flight taxi tests. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Centurion Quarter-scale Prototype Pre-flight Checkout

NASA Technical Reports Server (NTRS)

1997-01-01

Technicians perform pre-test checks of a battery-powered quarter-scale prototype of the remotely-piloted Centurion flying wing during taxi tests In March 1997 at California's El Mirage Dry Lake. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing in Flight during Firs

NASA Technical Reports Server (NTRS)

1997-01-01

Illuminated by early-morning sunlight, a quarter-scale model of the Solar-powered, remotely piloted Centurion ultra-high-altitude flying wing demonstrates its abilities during a March 1997 test flight. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing in Flight during Firs

NASA Technical Reports Server (NTRS)

1997-01-01

Silhouetted under a bright blue sky, a quarter-scale model of the Centurion solar-powered flying wing shows off its long, narrow wing as it flies over the broad expanse of El Mirage Dry Lake in Southern California during a March 1997 test flight. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing Landing during First

NASA Technical Reports Server (NTRS)

1997-01-01

A quarter-scale model of the future Centurion solar-powered high-altitude research aircraft settles in for landing after a March 1997 test flight at El Mirage Dry Lake, California. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing in Flight during Firs

NASA Technical Reports Server (NTRS)

1997-01-01

Illuminated by early-morning sunlight, a quarter-scale model of the solar-powered, remotely piloted Centurion ultra-high-altitude flying wing soars over California's Mojave Desert on a March 1997 test flight. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing in Flight during Firs

NASA Technical Reports Server (NTRS)

1997-01-01

With the snow-covered San Gabriel Mountains as a backdrop and a motorcycle-mounted chase crew alongside, a quarter-scale model of the Centurion solar-powered flying wing soars over El Mirage Dry Lake on an early test flight in March 1997. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing in Flight during Firs

NASA Technical Reports Server (NTRS)

1997-01-01

Framed by wispy contrails left by passing jets high above, a quarter-scale model of the Centurion solar-electric flying wing shows off its graceful lines during a March 1997 test flight at El Mirage Dry Lake in California's Mojave Desert. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing in Flight during Firs

NASA Technical Reports Server (NTRS)

1997-01-01

Trailed by a van carrying the remote pilot and observers, a radio-controlled quarter-scale model of the Centurion solar-electric flying wing makes a low pass over El Mirage Dry Lake in Southern California during a March 1997 test flight. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing on Lakebed

NASA Technical Reports Server (NTRS)

1997-01-01

A quarter-scale model of the Centurion solar-powered flying wing rests on the clay of El Mirage Dry Lake in Southern California's high desert after completion of of a March 1997 flight test. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing in Flight during Firs

NASA Technical Reports Server (NTRS)

1997-01-01

Silhouetted under a bright blue sky, a quarter-scale model of the Centurion solar-powered flying wing shows off its internal rib structure as it floats over the El Mirage Dry Lake in Southern California during a March 1997 test flight. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Quarter-scale Model of Solar-powered Centurion Ultra-high-altitude Flying Wing on Lakebed

NASA Technical Reports Server (NTRS)

1997-01-01

A quarter-scale model of the Centurion solar-powered flying wing rests on the clay of El Mirage Dry Lake in Southern California's high desert after completion of a March 1997 test flight. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Centurion in Flight over Lakebed

NASA Technical Reports Server (NTRS)

1998-01-01

The Centurion remotely piloted flying wing during an early morning test flight over the Rogers Dry Lake adjacent to at NASA's Dryden Flight Research Center, Edwards, California. The flight was one of an initial series of low-altitude, battery-powered test flights conducted in late 1998. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Numerical predictions of EML (electromagnetic launcher) system performance

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

Schnurr, N.M.; Kerrisk, J.F.; Davidson, R.F.

1987-01-01

The performance of an electromagnetic launcher (EML) depends on a large number of parameters, including the characteristics of the power supply, rail geometry, rail and insulator material properties, injection velocity, and projectile mass. EML system performance is frequently limited by structural or thermal effects in the launcher (railgun). A series of computer codes has been developed at the Los Alamos National Laboratory to predict EML system performance and to determine the structural and thermal constraints on barrel design. These codes include FLD, a two-dimensional electrostatic code used to calculate the high-frequency inductance gradient and surface current density distribution for themore » rails; TOPAZRG, a two-dimensional finite-element code that simultaneously analyzes thermal and electromagnetic diffusion in the rails; and LARGE, a code that predicts the performance of the entire EML system. Trhe NIKE2D code, developed at the Lawrence Livermore National Laboratory, is used to perform structural analyses of the rails. These codes have been instrumental in the design of the Lethality Test System (LTS) at Los Alamos, which has an ultimate goal of accelerating a 30-g projectile to a velocity of 15 km/s. The capabilities of the individual codes and the coupling of these codes to perform a comprehensive analysis is discussed in relation to the LTS design. Numerical predictions are compared with experimental data and presented for the LTS prototype tests.« less

Bayesian decision support for coding occupational injury data.

PubMed

Nanda, Gaurav; Grattan, Kathleen M; Chu, MyDzung T; Davis, Letitia K; Lehto, Mark R

2016-06-01

Studies on autocoding injury data have found that machine learning algorithms perform well for categories that occur frequently but often struggle with rare categories. Therefore, manual coding, although resource-intensive, cannot be eliminated. We propose a Bayesian decision support system to autocode a large portion of the data, filter cases for manual review, and assist human coders by presenting them top k prediction choices and a confusion matrix of predictions from Bayesian models. We studied the prediction performance of Single-Word (SW) and Two-Word-Sequence (TW) Naïve Bayes models on a sample of data from the 2011 Survey of Occupational Injury and Illness (SOII). We used the agreement in prediction results of SW and TW models, and various prediction strength thresholds for autocoding and filtering cases for manual review. We also studied the sensitivity of the top k predictions of the SW model, TW model, and SW-TW combination, and then compared the accuracy of the manually assigned codes to SOII data with that of the proposed system. The accuracy of the proposed system, assuming well-trained coders reviewing a subset of only 26% of cases flagged for review, was estimated to be comparable (86.5%) to the accuracy of the original coding of the data set (range: 73%-86.8%). Overall, the TW model had higher sensitivity than the SW model, and the accuracy of the prediction results increased when the two models agreed, and for higher prediction strength thresholds. The sensitivity of the top five predictions was 93%. The proposed system seems promising for coding injury data as it offers comparable accuracy and less manual coding. Accurate and timely coded occupational injury data is useful for surveillance as well as prevention activities that aim to make workplaces safer. Copyright © 2016 Elsevier Ltd and National Safety Council. All rights reserved.

Weighted bi-prediction for light field image coding

NASA Astrophysics Data System (ADS)

Conti, Caroline; Nunes, Paulo; Ducla Soares, Luís.

2017-09-01

Light field imaging based on a single-tier camera equipped with a microlens array - also known as integral, holoscopic, and plenoptic imaging - has currently risen up as a practical and prospective approach for future visual applications and services. However, successfully deploying actual light field imaging applications and services will require developing adequate coding solutions to efficiently handle the massive amount of data involved in these systems. In this context, self-similarity compensated prediction is a non-local spatial prediction scheme based on block matching that has been shown to achieve high efficiency for light field image coding based on the High Efficiency Video Coding (HEVC) standard. As previously shown by the authors, this is possible by simply averaging two predictor blocks that are jointly estimated from a causal search window in the current frame itself, referred to as self-similarity bi-prediction. However, theoretical analyses for motion compensated bi-prediction have suggested that it is still possible to achieve further rate-distortion performance improvements by adaptively estimating the weighting coefficients of the two predictor blocks. Therefore, this paper presents a comprehensive study of the rate-distortion performance for HEVC-based light field image coding when using different sets of weighting coefficients for self-similarity bi-prediction. Experimental results demonstrate that it is possible to extend the previous theoretical conclusions to light field image coding and show that the proposed adaptive weighting coefficient selection leads to up to 5 % of bit savings compared to the previous self-similarity bi-prediction scheme.

TFaNS Tone Fan Noise Design/Prediction System. Volume 2; User's Manual; 1.4

NASA Technical Reports Server (NTRS)

Topol, David A.; Eversman, Walter

1999-01-01

TFaNS is the Tone Fan Noise Design/Prediction System developed by Pratt & Whitney under contract to NASA Lewis (presently NASA Glenn). The purpose of this system is to predict tone noise emanating from a fan stage including the effects of reflection and transmission by the rotor and stator and by the duct inlet and nozzle. These effects have been added to an existing annular duct/isolated stator noise prediction capability. TFaNS consists of: the codes that compute the acoustic properties (reflection and transmission coefficients) of the various elements and write them to files. CUP3D: Fan Noise Coupling Code that reads these files, solves the coupling problem, and outputs the desired noise predictions. AWAKEN: CFD/Measured Wake Postprocessor which reformats CFD wake predictions and/or measured wake data so it can be used by the system. This volume of the report provides information on code input and file structure essential for potential users of TFANS. This report is divided into three volumes: Volume 1. System Description, CUP3D Technical Documentation, and Manual for Code Developers; Volume 2. User's Manual, TFANS Vers. 1.4; Volume 3. Evaluation of System Codes.

TFaNS Tone Fan Noise Design/Prediction System. Volume 3; Evaluation of System Codes

NASA Technical Reports Server (NTRS)

Topol, David A.

1999-01-01

TFANS is the Tone Fan Noise Design/Prediction System developed by Pratt & Whitney under contract to NASA Lewis (presently NASA Glenn). The purpose of this system is to predict tone noise emanating from a fan stage including the effects of reflection and transmission by the rotor and stator and by the duct inlet and nozzle. These effects have been added to an existing annular duct/isolated stator noise prediction capability. TFANS consists of: The codes that compute the acoustic properties (reflection and transmission coefficients) of the various elements and write them to files. Cup3D: Fan Noise Coupling Code that reads these files, solves the coupling problem, and outputs the desired noise predictions. AWAKEN: CFD/Measured Wake Postprocessor which reformats CFD wake predictions and/or measured wake data so it can be used by the system. This volume of the report evaluates TFANS versus full-scale and ADP 22" fig data using the semi-empirical wake modelling in the system. This report is divided into three volumes: Volume 1: System Description, CUP3D Technical Documentation, and Manual for Code Developers; Volume II: User's Manual, TFANS Version 1.4; Volume III: Evaluation of System Codes.

Role of N-Methyl-D-Aspartate Receptors in Action-Based Predictive Coding Deficits in Schizophrenia.

PubMed

Kort, Naomi S; Ford, Judith M; Roach, Brian J; Gunduz-Bruce, Handan; Krystal, John H; Jaeger, Judith; Reinhart, Robert M G; Mathalon, Daniel H

2017-03-15

Recent theoretical models of schizophrenia posit that dysfunction of the neural mechanisms subserving predictive coding contributes to symptoms and cognitive deficits, and this dysfunction is further posited to result from N-methyl-D-aspartate glutamate receptor (NMDAR) hypofunction. Previously, by examining auditory cortical responses to self-generated speech sounds, we demonstrated that predictive coding during vocalization is disrupted in schizophrenia. To test the hypothesized contribution of NMDAR hypofunction to this disruption, we examined the effects of the NMDAR antagonist, ketamine, on predictive coding during vocalization in healthy volunteers and compared them with the effects of schizophrenia. In two separate studies, the N1 component of the event-related potential elicited by speech sounds during vocalization (talk) and passive playback (listen) were compared to assess the degree of N1 suppression during vocalization, a putative measure of auditory predictive coding. In the crossover study, 31 healthy volunteers completed two randomly ordered test days, a saline day and a ketamine day. Event-related potentials during the talk/listen task were obtained before infusion and during infusion on both days, and N1 amplitudes were compared across days. In the case-control study, N1 amplitudes from 34 schizophrenia patients and 33 healthy control volunteers were compared. N1 suppression to self-produced vocalizations was significantly and similarly diminished by ketamine (Cohen's d = 1.14) and schizophrenia (Cohen's d = .85). Disruption of NMDARs causes dysfunction in predictive coding during vocalization in a manner similar to the dysfunction observed in schizophrenia patients, consistent with the theorized contribution of NMDAR hypofunction to predictive coding deficits in schizophrenia. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

TFaNS Tone Fan Noise Design/Prediction System. Volume 1; System Description, CUP3D Technical Documentation and Manual for Code Developers

NASA Technical Reports Server (NTRS)

Topol, David A.

1999-01-01

TFaNS is the Tone Fan Noise Design/Prediction System developed by Pratt & Whitney under contract to NASA Lewis (presently NASA Glenn). The purpose of this system is to predict tone noise emanating from a fan stage including the effects of reflection and transmission by the rotor and stator and by the duct inlet and nozzle. These effects have been added to an existing annular duct/isolated stator noise prediction capability. TFaNS consists of: The codes that compute the acoustic properties (reflection and transmission coefficients) of the various elements and write them to files. Cup3D: Fan Noise Coupling Code that reads these files, solves the coupling problem, and outputs the desired noise predictions. AWAKEN: CFD/Measured Wake Postprocessor which reformats CFD wake predictions and/or measured wake data so it can be used by the system. This volume of the report provides technical background for TFaNS including the organization of the system and CUP3D technical documentation. This document also provides information for code developers who must write Acoustic Property Files in the CUP3D format. This report is divided into three volumes: Volume I: System Description, CUP3D Technical Documentation, and Manual for Code Developers; Volume II: User's Manual, TFaNS Vers. 1.4; Volume III: Evaluation of System Codes.

Structured Set Intra Prediction With Discriminative Learning in a Max-Margin Markov Network for High Efficiency Video Coding

PubMed Central

Dai, Wenrui; Xiong, Hongkai; Jiang, Xiaoqian; Chen, Chang Wen

2014-01-01

This paper proposes a novel model on intra coding for High Efficiency Video Coding (HEVC), which simultaneously predicts blocks of pixels with optimal rate distortion. It utilizes the spatial statistical correlation for the optimal prediction based on 2-D contexts, in addition to formulating the data-driven structural interdependences to make the prediction error coherent with the probability distribution, which is desirable for successful transform and coding. The structured set prediction model incorporates a max-margin Markov network (M3N) to regulate and optimize multiple block predictions. The model parameters are learned by discriminating the actual pixel value from other possible estimates to maximize the margin (i.e., decision boundary bandwidth). Compared to existing methods that focus on minimizing prediction error, the M3N-based model adaptively maintains the coherence for a set of predictions. Specifically, the proposed model concurrently optimizes a set of predictions by associating the loss for individual blocks to the joint distribution of succeeding discrete cosine transform coefficients. When the sample size grows, the prediction error is asymptotically upper bounded by the training error under the decomposable loss function. As an internal step, we optimize the underlying Markov network structure to find states that achieve the maximal energy using expectation propagation. For validation, we integrate the proposed model into HEVC for optimal mode selection on rate-distortion optimization. The proposed prediction model obtains up to 2.85% bit rate reduction and achieves better visual quality in comparison to the HEVC intra coding. PMID:25505829

Microinstabilities in the pedestal region

NASA Astrophysics Data System (ADS)

Dickinson, David; Dudson, Benjamin; Wilson, Howard; Roach, Colin

2014-10-01

The regulation of transport at the pedestal top is important for the inter-ELM pedestal dynamics. Linear gyrokinetic analysis of the pedestal region during an ELM cycle on MAST has shown kinetic ballooning modes to be unstable at the knee of the pressure profile and in the steep pedestal region whilst microtearing modes (MTMs) dominate in the shallow gradient region inboard of the pedestal top. The transition between these instabilities at the pedestal knee has been observed in low and high collisionality MAST pedestals, and is likely to play an important role in the broadening of the pedestal. Nonlinear simulations are needed in this region to understand the microturbulence, the corresponding transport fluxes, and to gain further insight into the processes underlying the pedestal evolution. Such gyrokinetic simulations are numerically challenging and recent upgrades to the GS2 gyrokinetic code help improve their feasibility. We are also exploring reduced models that capture the relevant physics using the plasma simulation framework BOUT + + . An electromagnetic gyrofluid model has recently been implemented with BOUT + + that has significantly reduced computational cost compared to the gyrokinetic simulations against which it will be benchmarked. This work was funded by the RCUK Energy programme, EURATOM and a EUROFusion fellowship WP14-FRF-CCFE/Dickinson and was carried out using: HELIOS at IFERC, Japan; ARCHER (EPSRC Grant No. EP/L000237/1); HECToR (EPSRC Grant No. EP/H002081/1).

User's manual for the ALS base heating prediction code, volume 2

NASA Technical Reports Server (NTRS)

Reardon, John E.; Fulton, Michael S.

1992-01-01

The Advanced Launch System (ALS) Base Heating Prediction Code is based on a generalization of first principles in the prediction of plume induced base convective heating and plume radiation. It should be considered to be an approximate method for evaluating trends as a function of configuration variables because the processes being modeled are too complex to allow an accurate generalization. The convective methodology is based upon generalizing trends from four nozzle configurations, so an extension to use the code with strap-on boosters, multiple nozzle sizes, and variations in the propellants and chamber pressure histories cannot be precisely treated. The plume radiation is more amenable to precise computer prediction, but simplified assumptions are required to model the various aspects of the candidate configurations. Perhaps the most difficult area to characterize is the variation of radiation with altitude. The theory in the radiation predictions is described in more detail. This report is intended to familiarize a user with the interface operation and options, to summarize the limitations and restrictions of the code, and to provide information to assist in installing the code.

Content Coding of Psychotherapy Transcripts Using Labeled Topic Models.

PubMed

Gaut, Garren; Steyvers, Mark; Imel, Zac E; Atkins, David C; Smyth, Padhraic

2017-03-01

Psychotherapy represents a broad class of medical interventions received by millions of patients each year. Unlike most medical treatments, its primary mechanisms are linguistic; i.e., the treatment relies directly on a conversation between a patient and provider. However, the evaluation of patient-provider conversation suffers from critical shortcomings, including intensive labor requirements, coder error, nonstandardized coding systems, and inability to scale up to larger data sets. To overcome these shortcomings, psychotherapy analysis needs a reliable and scalable method for summarizing the content of treatment encounters. We used a publicly available psychotherapy corpus from Alexander Street press comprising a large collection of transcripts of patient-provider conversations to compare coding performance for two machine learning methods. We used the labeled latent Dirichlet allocation (L-LDA) model to learn associations between text and codes, to predict codes in psychotherapy sessions, and to localize specific passages of within-session text representative of a session code. We compared the L-LDA model to a baseline lasso regression model using predictive accuracy and model generalizability (measured by calculating the area under the curve (AUC) from the receiver operating characteristic curve). The L-LDA model outperforms the lasso logistic regression model at predicting session-level codes with average AUC scores of 0.79, and 0.70, respectively. For fine-grained level coding, L-LDA and logistic regression are able to identify specific talk-turns representative of symptom codes. However, model performance for talk-turn identification is not yet as reliable as human coders. We conclude that the L-LDA model has the potential to be an objective, scalable method for accurate automated coding of psychotherapy sessions that perform better than comparable discriminative methods at session-level coding and can also predict fine-grained codes.

Content Coding of Psychotherapy Transcripts Using Labeled Topic Models

PubMed Central

Gaut, Garren; Steyvers, Mark; Imel, Zac E; Atkins, David C; Smyth, Padhraic

2016-01-01

Psychotherapy represents a broad class of medical interventions received by millions of patients each year. Unlike most medical treatments, its primary mechanisms are linguistic; i.e., the treatment relies directly on a conversation between a patient and provider. However, the evaluation of patient-provider conversation suffers from critical shortcomings, including intensive labor requirements, coder error, non-standardized coding systems, and inability to scale up to larger data sets. To overcome these shortcomings, psychotherapy analysis needs a reliable and scalable method for summarizing the content of treatment encounters. We used a publicly-available psychotherapy corpus from Alexander Street press comprising a large collection of transcripts of patient-provider conversations to compare coding performance for two machine learning methods. We used the Labeled Latent Dirichlet Allocation (L-LDA) model to learn associations between text and codes, to predict codes in psychotherapy sessions, and to localize specific passages of within-session text representative of a session code. We compared the L-LDA model to a baseline lasso regression model using predictive accuracy and model generalizability (measured by calculating the area under the curve (AUC) from the receiver operating characteristic (ROC) curve). The L-LDA model outperforms the lasso logistic regression model at predicting session-level codes with average AUC scores of .79, and .70, respectively. For fine-grained level coding, L-LDA and logistic regression are able to identify specific talk-turns representative of symptom codes. However, model performance for talk-turn identification is not yet as reliable as human coders. We conclude that the L-LDA model has the potential to be an objective, scaleable method for accurate automated coding of psychotherapy sessions that performs better than comparable discriminative methods at session-level coding and can also predict fine-grained codes. PMID:26625437

PARC Navier-Stokes code upgrade and validation for high speed aeroheating predictions

NASA Technical Reports Server (NTRS)

Liver, Peter A.; Praharaj, Sarat C.; Seaford, C. Mark

1990-01-01

Applications of the PARC full Navier-Stokes code for hypersonic flowfield and aeroheating predictions around blunt bodies such as the Aeroassist Flight Experiment (AFE) and Aeroassisted Orbital Transfer Vehicle (AOTV) are evaluated. Two-dimensional/axisymmetric and three-dimensional perfect gas versions of the code were upgraded and tested against benchmark wind tunnel cases of hemisphere-cylinder, three-dimensional AFE forebody, and axisymmetric AFE and AOTV aerobrake/wake flowfields. PARC calculations are in good agreement with experimental data and results of similar computer codes. Difficulties encountered in flowfield and heat transfer predictions due to effects of grid density, boundary conditions such as singular stagnation line axis and artificial dissipation terms are presented together with subsequent improvements made to the code. The experience gained with the perfect gas code is being currently utilized in applications of an equilibrium air real gas PARC version developed at REMTECH.

Optical Analysis And Alignment Applications Using The Infrared Smartt Interferometer

NASA Astrophysics Data System (ADS)

Viswanathan, V. K.; Bolen, P. D.; Liberman, I.; Seery, B. D.

1981-12-01

The possiblility of using the infrared Smartt interferometer for optical analysis and alignment of infrared laser systems has been discussed previously. In this paper, optical analysis of the Gigawatt Test Facility at Los Alamos, as well as a deformable mirror manufactured by Rocketdyne, are discussed as examples of the technique. The possibility of optically characterizing, as well as aligning, pulsed high energy laser systems like Helios and Antares is discussed in some detail.

Optical analysis and alignment applications using the infrared Smartt interferometer

NASA Astrophysics Data System (ADS)

Viswanathan, V. K.; Bolen, P. D.; Liberman, I.; Seery, B. D.

The possibility of using the infrared Smartt interferometer for optical analysis and alignment of infrared laser systems has been discussed previously. In this paper, optical analysis of the Gigawatt Test Facility at Los Alamos, as well as a deformable mirror manufactured by Rocketdyne, are discussed as examples of the technique. The possibility of optically characterizing, as well as aligning, pulsed high energy laser systems like Helios and Antares is discussed in some detail.

A Fixed-Wing Aircraft Simulation Tool for Improving the efficiency of DoD Acquisition

DTIC Science & Technology

2015-10-05

simulation tool , CREATETM-AV Helios [12-14], a high fidelity rotary wing vehicle simulation tool , and CREATETM-AV DaVinci [15-16], a conceptual through...05/2015 Oct 2008-Sep 2015 A Fixed-Wing Aircraft Simulation Tool for Improving the Efficiency of DoD Acquisition Scott A. Morton and David R...multi-disciplinary fixed-wing virtual aircraft simulation tool incorporating aerodynamics, structural dynamics, kinematics, and kinetics. Kestrel allows

Energy Systems Integration Partnerships: NREL + Cogent Energy Systems

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

Berdahl, Sonja E

2017-08-09

NREL is collaborating with Cogent Energy Systems (Cogent) to introduce small-scale waste-to-energy technology in microgrids.The focus of the project is to test and demonstrate the feasibility, reliability, and usefulness of integrating electricity generated using a simulated syngas composition matching the syngas stream to be produced by a HelioStorm-based WTE gasifier to power a microgrid as a means of addressing and complementing the intermittency of other sources of electricity.

Computer programs to predict induced effects of jets exhausting into a crossflow

NASA Technical Reports Server (NTRS)

Perkins, S. C., Jr.; Mendenhall, M. R.

1984-01-01

A user's manual for two computer programs was developed to predict the induced effects of jets exhausting into a crossflow. Program JETPLT predicts pressures induced on an infinite flat plate by a jet exhausting at angles to the plate and Program JETBOD, in conjunction with a panel code, predicts pressures induced on a body of revolution by a jet exhausting normal to the surface. Both codes use a potential model of the jet and adjacent surface with empirical corrections for the viscous or nonpotential effects. This program manual contains a description of the use of both programs, instructions for preparation of input, descriptions of the output, limitations of the codes, and sample cases. In addition, procedures to extend both codes to include additional empirical correlations are described.

Implicit Coupling Approach for Simulation of Charring Carbon Ablators

NASA Technical Reports Server (NTRS)

Chen, Yih-Kanq; Gokcen, Tahir

2013-01-01

This study demonstrates that coupling of a material thermal response code and a flow solver with nonequilibrium gas/surface interaction for simulation of charring carbon ablators can be performed using an implicit approach. The material thermal response code used in this study is the three-dimensional version of Fully Implicit Ablation and Thermal response program, which predicts charring material thermal response and shape change on hypersonic space vehicles. The flow code solves the reacting Navier-Stokes equations using Data Parallel Line Relaxation method. Coupling between the material response and flow codes is performed by solving the surface mass balance in flow solver and the surface energy balance in material response code. Thus, the material surface recession is predicted in flow code, and the surface temperature and pyrolysis gas injection rate are computed in material response code. It is demonstrated that the time-lagged explicit approach is sufficient for simulations at low surface heating conditions, in which the surface ablation rate is not a strong function of the surface temperature. At elevated surface heating conditions, the implicit approach has to be taken, because the carbon ablation rate becomes a stiff function of the surface temperature, and thus the explicit approach appears to be inappropriate resulting in severe numerical oscillations of predicted surface temperature. Implicit coupling for simulation of arc-jet models is performed, and the predictions are compared with measured data. Implicit coupling for trajectory based simulation of Stardust fore-body heat shield is also conducted. The predicted stagnation point total recession is compared with that predicted using the chemical equilibrium surface assumption

Analysis and recognition of 5′ UTR intron splice sites in human pre-mRNA

PubMed Central

Eden, E.; Brunak, S.

2004-01-01

Prediction of splice sites in non-coding regions of genes is one of the most challenging aspects of gene structure recognition. We perform a rigorous analysis of such splice sites embedded in human 5′ untranslated regions (UTRs), and investigate correlations between this class of splice sites and other features found in the adjacent exons and introns. By restricting the training of neural network algorithms to ‘pure’ UTRs (not extending partially into protein coding regions), we for the first time investigate the predictive power of the splicing signal proper, in contrast to conventional splice site prediction, which typically relies on the change in sequence at the transition from protein coding to non-coding. By doing so, the algorithms were able to pick up subtler splicing signals that were otherwise masked by ‘coding’ noise, thus enhancing significantly the prediction of 5′ UTR splice sites. For example, the non-coding splice site predicting networks pick up compositional and positional bias in the 3′ ends of non-coding exons and 5′ non-coding intron ends, where cytosine and guanine are over-represented. This compositional bias at the true UTR donor sites is also visible in the synaptic weights of the neural networks trained to identify UTR donor sites. Conventional splice site prediction methods perform poorly in UTRs because the reading frame pattern is absent. The NetUTR method presented here performs 2–3-fold better compared with NetGene2 and GenScan in 5′ UTRs. We also tested the 5′ UTR trained method on protein coding regions, and discovered, surprisingly, that it works quite well (although it cannot compete with NetGene2). This indicates that the local splicing pattern in UTRs and coding regions is largely the same. The NetUTR method is made publicly available at www.cbs.dtu.dk/services/NetUTR. PMID:14960723

Aeroacoustic Prediction Codes

NASA Technical Reports Server (NTRS)

Gliebe, P; Mani, R.; Shin, H.; Mitchell, B.; Ashford, G.; Salamah, S.; Connell, S.; Huff, Dennis (Technical Monitor)

2000-01-01

This report describes work performed on Contract NAS3-27720AoI 13 as part of the NASA Advanced Subsonic Transport (AST) Noise Reduction Technology effort. Computer codes were developed to provide quantitative prediction, design, and analysis capability for several aircraft engine noise sources. The objective was to provide improved, physics-based tools for exploration of noise-reduction concepts and understanding of experimental results. Methods and codes focused on fan broadband and 'buzz saw' noise and on low-emissions combustor noise and compliment work done by other contractors under the NASA AST program to develop methods and codes for fan harmonic tone noise and jet noise. The methods and codes developed and reported herein employ a wide range of approaches, from the strictly empirical to the completely computational, with some being semiempirical analytical, and/or analytical/computational. Emphasis was on capturing the essential physics while still considering method or code utility as a practical design and analysis tool for everyday engineering use. Codes and prediction models were developed for: (1) an improved empirical correlation model for fan rotor exit flow mean and turbulence properties, for use in predicting broadband noise generated by rotor exit flow turbulence interaction with downstream stator vanes: (2) fan broadband noise models for rotor and stator/turbulence interaction sources including 3D effects, noncompact-source effects. directivity modeling, and extensions to the rotor supersonic tip-speed regime; (3) fan multiple-pure-tone in-duct sound pressure prediction methodology based on computational fluid dynamics (CFD) analysis; and (4) low-emissions combustor prediction methodology and computer code based on CFD and actuator disk theory. In addition. the relative importance of dipole and quadrupole source mechanisms was studied using direct CFD source computation for a simple cascadeigust interaction problem, and an empirical combustor-noise correlation model was developed from engine acoustic test results. This work provided several insights on potential approaches to reducing aircraft engine noise. Code development is described in this report, and those insights are discussed.

Efficient depth intraprediction method for H.264/AVC-based three-dimensional video coding

NASA Astrophysics Data System (ADS)

Oh, Kwan-Jung; Oh, Byung Tae

2015-04-01

We present an intracoding method that is applicable to depth map coding in multiview plus depth systems. Our approach combines skip prediction and plane segmentation-based prediction. The proposed depth intraskip prediction uses the estimated direction at both the encoder and decoder, and does not need to encode residual data. Our plane segmentation-based intraprediction divides the current block into biregions, and applies a different prediction scheme for each segmented region. This method avoids incorrect estimations across different regions, resulting in higher prediction accuracy. Simulation results demonstrate that the proposed scheme is superior to H.264/advanced video coding intraprediction and has the ability to improve the subjective rendering quality.

Numerical simulation of experiments in the Giant Planet Facility

NASA Technical Reports Server (NTRS)

Green, M. J.; Davy, W. C.

1979-01-01

Utilizing a series of existing computer codes, ablation experiments in the Giant Planet Facility are numerically simulated. Of primary importance is the simulation of the low Mach number shock layer that envelops the test model. The RASLE shock-layer code, used in the Jupiter entry probe heat-shield design, is adapted to the experimental conditions. RASLE predictions for radiative and convective heat fluxes are in good agreement with calorimeter measurements. In simulating carbonaceous ablation experiments, the RASLE code is coupled directly with the CMA material response code. For the graphite models, predicted and measured recessions agree very well. Predicted recession for the carbon phenolic models is 50% higher than that measured. This is the first time codes used for the Jupiter probe design have been compared with experiments.

Fast bi-directional prediction selection in H.264/MPEG-4 AVC temporal scalable video coding.

PubMed

Lin, Hung-Chih; Hang, Hsueh-Ming; Peng, Wen-Hsiao

2011-12-01

In this paper, we propose a fast algorithm that efficiently selects the temporal prediction type for the dyadic hierarchical-B prediction structure in the H.264/MPEG-4 temporal scalable video coding (SVC). We make use of the strong correlations in prediction type inheritance to eliminate the superfluous computations for the bi-directional (BI) prediction in the finer partitions, 16×8/8×16/8×8 , by referring to the best temporal prediction type of 16 × 16. In addition, we carefully examine the relationship in motion bit-rate costs and distortions between the BI and the uni-directional temporal prediction types. As a result, we construct a set of adaptive thresholds to remove the unnecessary BI calculations. Moreover, for the block partitions smaller than 8 × 8, either the forward prediction (FW) or the backward prediction (BW) is skipped based upon the information of their 8 × 8 partitions. Hence, the proposed schemes can efficiently reduce the extensive computational burden in calculating the BI prediction. As compared to the JSVM 9.11 software, our method saves the encoding time from 48% to 67% for a large variety of test videos over a wide range of coding bit-rates and has only a minor coding performance loss. © 2011 IEEE

A 3D-CFD code for accurate prediction of fluid flows and fluid forces in seals

NASA Technical Reports Server (NTRS)

Athavale, M. M.; Przekwas, A. J.; Hendricks, R. C.

1994-01-01

Current and future turbomachinery requires advanced seal configurations to control leakage, inhibit mixing of incompatible fluids and to control the rotodynamic response. In recognition of a deficiency in the existing predictive methodology for seals, a seven year effort was established in 1990 by NASA's Office of Aeronautics Exploration and Technology, under the Earth-to-Orbit Propulsion program, to develop validated Computational Fluid Dynamics (CFD) concepts, codes and analyses for seals. The effort will provide NASA and the U.S. Aerospace Industry with advanced CFD scientific codes and industrial codes for analyzing and designing turbomachinery seals. An advanced 3D CFD cylindrical seal code has been developed, incorporating state-of-the-art computational methodology for flow analysis in straight, tapered and stepped seals. Relevant computational features of the code include: stationary/rotating coordinates, cylindrical and general Body Fitted Coordinates (BFC) systems, high order differencing schemes, colocated variable arrangement, advanced turbulence models, incompressible/compressible flows, and moving grids. This paper presents the current status of code development, code demonstration for predicting rotordynamic coefficients, numerical parametric study of entrance loss coefficients for generic annular seals, and plans for code extensions to labyrinth, damping, and other seal configurations.

TAS: A Transonic Aircraft/Store flow field prediction code

NASA Technical Reports Server (NTRS)

Thompson, D. S.

1983-01-01

A numerical procedure has been developed that has the capability to predict the transonic flow field around an aircraft with an arbitrarily located, separated store. The TAS code, the product of a joint General Dynamics/NASA ARC/AFWAL research and development program, will serve as the basis for a comprehensive predictive method for aircraft with arbitrary store loadings. This report described the numerical procedures employed to simulate the flow field around a configuration of this type. The validity of TAS code predictions is established by comparison with existing experimental data. In addition, future areas of development of the code are outlined. A brief description of code utilization is also given in the Appendix. The aircraft/store configuration is simulated using a mesh embedding approach. The computational domain is discretized by three meshes: (1) a planform-oriented wing/body fine mesh, (2) a cylindrical store mesh, and (3) a global Cartesian crude mesh. This embedded mesh scheme enables simulation of stores with fins of arbitrary angular orientation.

Modification of codes NUALGAM and BREMRAD, Volume 1

NASA Technical Reports Server (NTRS)

Steyn, J. J.; Huang, R.; Firstenberg, H.

1971-01-01

The NUGAM2 code predicts forward and backward angular energy differential and integrated distributions for gamma photons and fluorescent radiation emerging from finite laminar transport media. It determines buildup and albedo data for scientific research and engineering purposes; it also predicts the emission characteristics of finite radioisotope sources. The results are shown to be in very good agreement with available published data. The code predicts data for many situations in which no published data is available in the energy range up to 5 MeV. The NUGAM3 code predicts the pulse height response of inorganic (NaI and CsI) scintillation detectors to gamma photons. Because it allows the scintillator to be clad and mounted on a photomultiplier as in the experimental or industrial application, it is a more practical and thus useful code than others previously reported. Results are in excellent agreement with published Monte Carlo and experimental data in the energy range up to 4.5 MeV.

Dream to Predict? REM Dreaming as Prospective Coding

PubMed Central

Llewellyn, Sue

2016-01-01

The dream as prediction seems inherently improbable. The bizarre occurrences in dreams never characterize everyday life. Dreams do not come true! But assuming that bizarreness negates expectations may rest on a misunderstanding of how the predictive brain works. In evolutionary terms, the ability to rapidly predict what sensory input implies—through expectations derived from discerning patterns in associated past experiences—would have enhanced fitness and survival. For example, food and water are essential for survival, associating past experiences (to identify location patterns) predicts where they can be found. Similarly, prediction may enable predator identification from what would have been only a fleeting and ambiguous stimulus—without prior expectations. To confront the many challenges associated with natural settings, visual perception is vital for humans (and most mammals) and often responses must be rapid. Predictive coding during wake may, therefore, be based on unconscious imagery so that visual perception is maintained and appropriate motor actions triggered quickly. Speed may also dictate the form of the imagery. Bizarreness, during REM dreaming, may result from a prospective code fusing phenomena with the same meaning—within a particular context. For example, if the context is possible predation, from the perspective of the prey two different predators can both mean the same (i.e., immediate danger) and require the same response (e.g., flight). Prospective coding may also prune redundancy from memories, to focus the image on the contextually-relevant elements only, thus, rendering the non-relevant phenomena indeterminate—another aspect of bizarreness. In sum, this paper offers an evolutionary take on REM dreaming as a form of prospective coding which identifies a probabilistic pattern in past events. This pattern is portrayed in an unconscious, associative, sensorimotor image which may support cognition in wake through being mobilized as a predictive code. A particular dream illustrates. PMID:26779078

Advanced propeller noise prediction in the time domain

NASA Technical Reports Server (NTRS)

Farassat, F.; Dunn, M. H.; Spence, P. L.

1992-01-01

The time domain code ASSPIN gives acousticians a powerful technique of advanced propeller noise prediction. Except for nonlinear effects, the code uses exact solutions of the Ffowcs Williams-Hawkings equation with exact blade geometry and kinematics. By including nonaxial inflow, periodic loading noise, and adaptive time steps to accelerate computer execution, the development of this code becomes complete.

Great Expectations: Is there Evidence for Predictive Coding in Auditory Cortex?

PubMed

Heilbron, Micha; Chait, Maria

2017-08-04

Predictive coding is possibly one of the most influential, comprehensive, and controversial theories of neural function. While proponents praise its explanatory potential, critics object that key tenets of the theory are untested or even untestable. The present article critically examines existing evidence for predictive coding in the auditory modality. Specifically, we identify five key assumptions of the theory and evaluate each in the light of animal, human and modeling studies of auditory pattern processing. For the first two assumptions - that neural responses are shaped by expectations and that these expectations are hierarchically organized - animal and human studies provide compelling evidence. The anticipatory, predictive nature of these expectations also enjoys empirical support, especially from studies on unexpected stimulus omission. However, for the existence of separate error and prediction neurons, a key assumption of the theory, evidence is lacking. More work exists on the proposed oscillatory signatures of predictive coding, and on the relation between attention and precision. However, results on these latter two assumptions are mixed or contradictory. Looking to the future, more collaboration between human and animal studies, aided by model-based analyses will be needed to test specific assumptions and implementations of predictive coding - and, as such, help determine whether this popular grand theory can fulfill its expectations. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Metaworkflows and Workflow Interoperability for Heliophysics

NASA Astrophysics Data System (ADS)

Pierantoni, Gabriele; Carley, Eoin P.

2014-06-01

Heliophysics is a relatively new branch of physics that investigates the relationship between the Sun and the other bodies of the solar system. To investigate such relationships, heliophysicists can rely on various tools developed by the community. Some of these tools are on-line catalogues that list events (such as Coronal Mass Ejections, CMEs) and their characteristics as they were observed on the surface of the Sun or on the other bodies of the Solar System. Other tools offer on-line data analysis and access to images and data catalogues. During their research, heliophysicists often perform investigations that need to coordinate several of these services and to repeat these complex operations until the phenomena under investigation are fully analyzed. Heliophysicists combine the results of these services; this service orchestration is best suited for workflows. This approach has been investigated in the HELIO project. The HELIO project developed an infrastructure for a Virtual Observatory for Heliophysics and implemented service orchestration using TAVERNA workflows. HELIO developed a set of workflows that proved to be useful but lacked flexibility and re-usability. The TAVERNA workflows also needed to be executed directly in TAVERNA workbench, and this forced all users to learn how to use the workbench. Within the SCI-BUS and ER-FLOW projects, we have started an effort to re-think and re-design the heliophysics workflows with the aim of fostering re-usability and ease of use. We base our approach on two key concepts, that of meta-workflows and that of workflow interoperability. We have divided the produced workflows in three different layers. The first layer is Basic Workflows, developed both in the TAVERNA and WS-PGRADE languages. They are building blocks that users compose to address their scientific challenges. They implement well-defined Use Cases that usually involve only one service. The second layer is Science Workflows usually developed in TAVERNA. They- implement Science Cases (the definition of a scientific challenge) by composing different Basic Workflows. The third and last layer,Iterative Science Workflows, is developed in WSPGRADE. It executes sub-workflows (either Basic or Science Workflows) as parameter sweep jobs to investigate Science Cases on large multiple data sets. So far, this approach has proven fruitful for three Science Cases of which one has been completed and two are still being tested.

Verification of intensity modulated radiation therapy beams using a tissue equivalent plastic scintillator dosimetry system

NASA Astrophysics Data System (ADS)

Petric, Martin Peter

This thesis describes the development and implementation of a novel method for the dosimetric verification of intensity modulated radiation therapy (IMRT) fields with several advantages over current techniques. Through the use of a tissue equivalent plastic scintillator sheet viewed by a charge-coupled device (CCD) camera, this method provides a truly tissue equivalent dosimetry system capable of efficiently and accurately performing field-by-field verification of IMRT plans. This work was motivated by an initial study comparing two IMRT treatment planning systems. The clinical functionality of BrainLAB's BrainSCAN and Varian's Helios IMRT treatment planning systems were compared in terms of implementation and commissioning, dose optimization, and plan assessment. Implementation and commissioning revealed differences in the beam data required to characterize the beam prior to use with the BrainSCAN system requiring higher resolution data compared to Helios. This difference was found to impact on the ability of the systems to accurately calculate dose for highly modulated fields, with BrainSCAN being more successful than Helios. The dose optimization and plan assessment comparisons revealed that while both systems use considerably different optimization algorithms and user-control interfaces, they are both capable of producing substantially equivalent dose plans. The extensive use of dosimetric verification techniques in the IMRT treatment planning comparison study motivated the development and implementation of a novel IMRT dosimetric verification system. The system consists of a water-filled phantom with a tissue equivalent plastic scintillator sheet built into the top surface. Scintillation light is reflected by a plastic mirror within the phantom towards a viewing window where it is captured using a CCD camera. Optical photon spread is removed using a micro-louvre optical collimator and by deconvolving a glare kernel from the raw images. Characterization of this new dosimetric verification system indicates excellent dose response and spatial linearity, high spatial resolution, and good signal uniformity and reproducibility. Dosimetric results from square fields, dynamic wedged fields, and a 7-field head and neck IMRT treatment plan indicate good agreement with film dosimetry distributions. Efficiency analysis of the system reveals a 50% reduction in time requirements for field-by-field verification of a 7-field IMRT treatment plan compared to film dosimetry.

The NASA-LeRC wind turbine sound prediction code

NASA Technical Reports Server (NTRS)

Viterna, L. A.

1981-01-01

Development of the wind turbine sound prediction code began as part of an effort understand and reduce the noise generated by Mod-1. Tone sound levels predicted with this code are in good agreement with measured data taken in the vicinity Mod-1 wind turbine (less than 2 rotor diameters). Comparison in the far field indicates that propagation effects due to terrain and atmospheric conditions may amplify the actual sound levels by 6 dB. Parametric analysis using the code shows that the predominant contributors to Mod-1 rotor noise are (1) the velocity deficit in the wake of the support tower, (2) the high rotor speed, and (3) off-optimum operation.

Navier-Stokes and Comprehensive Analysis Performance Predictions of the NREL Phase VI Experiment

NASA Technical Reports Server (NTRS)

Duque, Earl P. N.; Burklund, Michael D.; Johnson, Wayne

2003-01-01

A vortex lattice code, CAMRAD II, and a Reynolds-Averaged Navier-Stoke code, OVERFLOW-D2, were used to predict the aerodynamic performance of a two-bladed horizontal axis wind turbine. All computations were compared with experimental data that was collected at the NASA Ames Research Center 80- by 120-Foot Wind Tunnel. Computations were performed for both axial as well as yawed operating conditions. Various stall delay models and dynamics stall models were used by the CAMRAD II code. Comparisons between the experimental data and computed aerodynamic loads show that the OVERFLOW-D2 code can accurately predict the power and spanwise loading of a wind turbine rotor.

Progressive Dictionary Learning with Hierarchical Predictive Structure for Scalable Video Coding.

PubMed

Dai, Wenrui; Shen, Yangmei; Xiong, Hongkai; Jiang, Xiaoqian; Zou, Junni; Taubman, David

2017-04-12

Dictionary learning has emerged as a promising alternative to the conventional hybrid coding framework. However, the rigid structure of sequential training and prediction degrades its performance in scalable video coding. This paper proposes a progressive dictionary learning framework with hierarchical predictive structure for scalable video coding, especially in low bitrate region. For pyramidal layers, sparse representation based on spatio-temporal dictionary is adopted to improve the coding efficiency of enhancement layers (ELs) with a guarantee of reconstruction performance. The overcomplete dictionary is trained to adaptively capture local structures along motion trajectories as well as exploit the correlations between neighboring layers of resolutions. Furthermore, progressive dictionary learning is developed to enable the scalability in temporal domain and restrict the error propagation in a close-loop predictor. Under the hierarchical predictive structure, online learning is leveraged to guarantee the training and prediction performance with an improved convergence rate. To accommodate with the stateof- the-art scalable extension of H.264/AVC and latest HEVC, standardized codec cores are utilized to encode the base and enhancement layers. Experimental results show that the proposed method outperforms the latest SHVC and HEVC simulcast over extensive test sequences with various resolutions.

Capstone: A Geometry-Centric Platform to Enable Physics-Based Simulation and Design of Systems

DTIC Science & Technology

2015-10-05

foundation for the air-vehicle early design tool DaVinci being developed by CREATETM-AV project to enable development of associative models of air...CREATETM-AV solvers Kestrel [11] and Helios [16,17]. Furthermore, it is the foundation for the CREATETM-AV’s DaVinci [9] tool that provides a... Tools and Environments (CREATETM) program [6] aimed at developing a suite of high- performance physics-based computational tools addressing the needs

Coronal propagation of flare associated electrons and protons

NASA Technical Reports Server (NTRS)

Schellert, G.; Wibberenz, G.; Kunow, H.

1985-01-01

A statistical study of characteristic times and intensities of 36 solar particle events observed between 1977 and 1979 by the Kiel Cosmic Ray Experiment on board HELIOS-1 and -2 has been carried out. For approx. 0.5 MeV electrons we order the times of maximum and the absolute intensities with respect to angular distance from the parent flare. Discussion of coronal parameters in terms of Reid's model leads to typical time constants for coronal diffusion and escape.

Evolution of the south Pacific helium plume over the past three decades

NASA Astrophysics Data System (ADS)

Lupton, J. E.; Jenkins, W. J.

2017-05-01

The recent GEOTRACES Eastern Pacific Zonal Transect in 2013 crossed the East Pacific Rise at 15°S following the same track as the 1987 Helios Expedition along the core of the mid-depth helium plume that spreads westward from the East Pacific Rise (EPR) axis. The fact that several stations were co-located with the earlier Helios stations has allowed a detailed comparison of the changes in the helium plume over the intervening 26 years. While the plume in many areas is unchanged, there is a marked decrease in plume intensity at longitude 120°W in the 2013 data which was not present in 1987. Recent radioisotope measurements along the plume track suggest that this decrease is due to the intrusion of a different water mass into the plume, rather than a modulation of hydrothermal input on the EPR axis. Analysis of GEOTRACES hydrographic data shows excess heat present in the plume up to 0.04°C, corresponding to a 3He/heat ratio of ˜2.5 × 10-18 mol J-1, similar to that found in mature hydrothermal vents. RAFOS floats deployed in 1987 indicate an average westward transport of ˜0.3 cm s-1 at 2500 m depth in the off-axis plume, in agreement with recent estimates of ˜0.4 cm s-1 based on "aging" of the plume from 227Ac/3He ratios.

Neural dynamics of reward probability coding: a Magnetoencephalographic study in humans

PubMed Central

Thomas, Julie; Vanni-Mercier, Giovanna; Dreher, Jean-Claude

2013-01-01

Prediction of future rewards and discrepancy between actual and expected outcomes (prediction error) are crucial signals for adaptive behavior. In humans, a number of fMRI studies demonstrated that reward probability modulates these two signals in a large brain network. Yet, the spatio-temporal dynamics underlying the neural coding of reward probability remains unknown. Here, using magnetoencephalography, we investigated the neural dynamics of prediction and reward prediction error computations while subjects learned to associate cues of slot machines with monetary rewards with different probabilities. We showed that event-related magnetic fields (ERFs) arising from the visual cortex coded the expected reward value 155 ms after the cue, demonstrating that reward value signals emerge early in the visual stream. Moreover, a prediction error was reflected in ERF peaking 300 ms after the rewarded outcome and showing decreasing amplitude with higher reward probability. This prediction error signal was generated in a network including the anterior and posterior cingulate cortex. These findings pinpoint the spatio-temporal characteristics underlying reward probability coding. Together, our results provide insights into the neural dynamics underlying the ability to learn probabilistic stimuli-reward contingencies. PMID:24302894

Maneuvering Rotorcraft Noise Prediction: A New Code for a New Problem

NASA Technical Reports Server (NTRS)

Brentner, Kenneth S.; Bres, Guillaume A.; Perez, Guillaume; Jones, Henry E.

2002-01-01

This paper presents the unique aspects of the development of an entirely new maneuver noise prediction code called PSU-WOPWOP. The main focus of the code is the aeroacoustic aspects of the maneuver noise problem, when the aeromechanical input data are provided (namely aircraft and blade motion, blade airloads). The PSU-WOPWOP noise prediction capability was developed for rotors in steady and transient maneuvering flight. Featuring an object-oriented design, the code allows great flexibility for complex rotor configuration and motion (including multiple rotors and full aircraft motion). The relative locations and number of hinges, flexures, and body motions can be arbitrarily specified to match the any specific rotorcraft. An analysis of algorithm efficiency is performed for maneuver noise prediction along with a description of the tradeoffs made specifically for the maneuvering noise problem. Noise predictions for the main rotor of a rotorcraft in steady descent, transient (arrested) descent, hover and a mild "pop-up" maneuver are demonstrated.

Mode-dependent templates and scan order for H.264/AVC-based intra lossless coding.

PubMed

Gu, Zhouye; Lin, Weisi; Lee, Bu-Sung; Lau, Chiew Tong; Sun, Ming-Ting

2012-09-01

In H.264/advanced video coding (AVC), lossless coding and lossy coding share the same entropy coding module. However, the entropy coders in the H.264/AVC standard were original designed for lossy video coding and do not yield adequate performance for lossless video coding. In this paper, we analyze the problem with the current lossless coding scheme and propose a mode-dependent template (MD-template) based method for intra lossless coding. By exploring the statistical redundancy of the prediction residual in the H.264/AVC intra prediction modes, more zero coefficients are generated. By designing a new scan order for each MD-template, the scanned coefficients sequence fits the H.264/AVC entropy coders better. A fast implementation algorithm is also designed. With little computation increase, experimental results confirm that the proposed fast algorithm achieves about 7.2% bit saving compared with the current H.264/AVC fidelity range extensions high profile.

Performing aggressive code optimization with an ability to rollback changes made by the aggressive optimizations

DOEpatents

Gschwind, Michael K

2013-07-23

Mechanisms for aggressively optimizing computer code are provided. With these mechanisms, a compiler determines an optimization to apply to a portion of source code and determines if the optimization as applied to the portion of source code will result in unsafe optimized code that introduces a new source of exceptions being generated by the optimized code. In response to a determination that the optimization is an unsafe optimization, the compiler generates an aggressively compiled code version, in which the unsafe optimization is applied, and a conservatively compiled code version in which the unsafe optimization is not applied. The compiler stores both versions and provides them for execution. Mechanisms are provided for switching between these versions during execution in the event of a failure of the aggressively compiled code version. Moreover, predictive mechanisms are provided for predicting whether such a failure is likely.

Improved lossless intra coding for H.264/MPEG-4 AVC.

PubMed

Lee, Yung-Lyul; Han, Ki-Hun; Sullivan, Gary J

2006-09-01

A new lossless intra coding method based on sample-by-sample differential pulse code modulation (DPCM) is presented as an enhancement of the H.264/MPEG-4 AVC standard. The H.264/AVC design includes a multidirectional spatial prediction method to reduce spatial redundancy by using neighboring samples as a prediction for the samples in a block of data to be encoded. In the new lossless intra coding method, the spatial prediction is performed based on samplewise DPCM instead of in the block-based manner used in the current H.264/AVC standard, while the block structure is retained for the residual difference entropy coding process. We show that the new method, based on samplewise DPCM, does not have a major complexity penalty, despite its apparent pipeline dependencies. Experiments show that the new lossless intra coding method reduces the bit rate by approximately 12% in comparison with the lossless intra coding method previously included in the H.264/AVC standard. As a result, the new method is currently being adopted into the H.264/AVC standard in a new enhancement project.

Predictive value of the present-on-admission indicator for hospital-acquired venous thromboembolism.

PubMed

Khanna, Raman R; Kim, Sharon B; Jenkins, Ian; El-Kareh, Robert; Afsarmanesh, Nasim; Amin, Alpesh; Sand, Heather; Auerbach, Andrew; Chia, Catherine Y; Maynard, Gregory; Romano, Patrick S; White, Richard H

2015-04-01

Hospital-acquired venous thromboembolic (HA-VTE) events are an important, preventable cause of morbidity and death, but accurately identifying HA-VTE events requires labor-intensive chart review. Administrative diagnosis codes and their associated "present-on-admission" (POA) indicator might allow automated identification of HA-VTE events, but only if VTE codes are accurately flagged "not present-on-admission" (POA=N). New codes were introduced in 2009 to improve accuracy. We identified all medical patients with at least 1 VTE "other" discharge diagnosis code from 5 academic medical centers over a 24-month period. We then sampled, within each center, patients with VTE codes flagged POA=N or POA=U (insufficient documentation) and POA=Y or POA=W (timing clinically uncertain) and abstracted each chart to clarify VTE timing. All events that were not clearly POA were classified as HA-VTE. We then calculated predictive values of the POA=N/U flags for HA-VTE and the POA=Y/W flags for non-HA-VTE. Among 2070 cases with at least 1 "other" VTE code, we found 339 codes flagged POA=N/U and 1941 flagged POA=Y/W. Among 275 POA=N/U abstracted codes, 75.6% (95% CI, 70.1%-80.6%) were HA-VTE; among 291 POA=Y/W abstracted events, 73.5% (95% CI, 68.0%-78.5%) were non-HA-VTE. Extrapolating from this sample, we estimated that 59% of actual HA-VTE codes were incorrectly flagged POA=Y/W. POA indicator predictive values did not improve after new codes were introduced in 2009. The predictive value of VTE events flagged POA=N/U for HA-VTE was 75%. However, sole reliance on this flag may substantially underestimate the incidence of HA-VTE.

Some practical universal noiseless coding techniques, part 3, module PSl14,K+

NASA Technical Reports Server (NTRS)

Rice, Robert F.

1991-01-01

The algorithmic definitions, performance characterizations, and application notes for a high-performance adaptive noiseless coding module are provided. Subsets of these algorithms are currently under development in custom very large scale integration (VLSI) at three NASA centers. The generality of coding algorithms recently reported is extended. The module incorporates a powerful adaptive noiseless coder for Standard Data Sources (i.e., sources whose symbols can be represented by uncorrelated non-negative integers, where smaller integers are more likely than the larger ones). Coders can be specified to provide performance close to the data entropy over any desired dynamic range (of entropy) above 0.75 bit/sample. This is accomplished by adaptively choosing the best of many efficient variable-length coding options to use on each short block of data (e.g., 16 samples) All code options used for entropies above 1.5 bits/sample are 'Huffman Equivalent', but they require no table lookups to implement. The coding can be performed directly on data that have been preprocessed to exhibit the characteristics of a standard source. Alternatively, a built-in predictive preprocessor can be used where applicable. This built-in preprocessor includes the familiar 1-D predictor followed by a function that maps the prediction error sequences into the desired standard form. Additionally, an external prediction can be substituted if desired. A broad range of issues dealing with the interface between the coding module and the data systems it might serve are further addressed. These issues include: multidimensional prediction, archival access, sensor noise, rate control, code rate improvements outside the module, and the optimality of certain internal code options.

TRAC-PF1 code verification with data from the OTIS test facility. [Once-Through Intergral System

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

Childerson, M.T.; Fujita, R.K.

1985-01-01

A computer code (TRAC-PF1/MOD1) developed for predicting transient thermal and hydraulic integral nuclear steam supply system (NSSS) response was benchmarked. Post-small break loss-of-coolant accident (LOCA) data from a scaled, experimental facility, designated the One-Through Integral System (OTIS), were obtained for the Babcock and Wilcox NSSS and compared to TRAC predictions. The OTIS tests provided a challenging small break LOCA data set for TRAC verification. The major phases of a small break LOCA observed in the OTIS tests included pressurizer draining and loop saturation, intermittent reactor coolant system circulation, boiler-condenser mode, and the initial stages of refill. The TRAC code wasmore » successful in predicting OTIS loop conditions (system pressures and temperatures) after modification of the steam generator model. In particular, the code predicted both pool and auxiliary-feedwater initiated boiler-condenser mode heat transfer.« less

Predictions of Supersonic Jet Mixing and Shock-Associated Noise Compared With Measured Far-Field Data

NASA Technical Reports Server (NTRS)

Dahl, Milo D.

2010-01-01

Codes for predicting supersonic jet mixing and broadband shock-associated noise were assessed using a database containing noise measurements of a jet issuing from a convergent nozzle. Two types of codes were used to make predictions. Fast running codes containing empirical models were used to compute both the mixing noise component and the shock-associated noise component of the jet noise spectrum. One Reynolds-averaged, Navier-Stokes-based code was used to compute only the shock-associated noise. To enable the comparisons of the predicted component spectra with data, the measured total jet noise spectra were separated into mixing noise and shock-associated noise components. Comparisons were made for 1/3-octave spectra and some power spectral densities using data from jets operating at 24 conditions covering essentially 6 fully expanded Mach numbers with 4 total temperature ratios.

Development of Tripropellant CFD Design Code

NASA Technical Reports Server (NTRS)

Farmer, Richard C.; Cheng, Gary C.; Anderson, Peter G.

1998-01-01

A tripropellant, such as GO2/H2/RP-1, CFD design code has been developed to predict the local mixing of multiple propellant streams as they are injected into a rocket motor. The code utilizes real fluid properties to account for the mixing and finite-rate combustion processes which occur near an injector faceplate, thus the analysis serves as a multi-phase homogeneous spray combustion model. Proper accounting of the combustion allows accurate gas-side temperature predictions which are essential for accurate wall heating analyses. The complex secondary flows which are predicted to occur near a faceplate cannot be quantitatively predicted by less accurate methodology. Test cases have been simulated to describe an axisymmetric tripropellant coaxial injector and a 3-dimensional RP-1/LO2 impinger injector system. The analysis has been shown to realistically describe such injector combustion flowfields. The code is also valuable to design meaningful future experiments by determining the critical location and type of measurements needed.

Ducted-Fan Engine Acoustic Predictions using a Navier-Stokes Code

NASA Technical Reports Server (NTRS)

Rumsey, C. L.; Biedron, R. T.; Farassat, F.; Spence, P. L.

1998-01-01

A Navier-Stokes computer code is used to predict one of the ducted-fan engine acoustic modes that results from rotor-wake/stator-blade interaction. A patched sliding-zone interface is employed to pass information between the moving rotor row and the stationary stator row. The code produces averaged aerodynamic results downstream of the rotor that agree well with a widely used average-passage code. The acoustic mode of interest is generated successfully by the code and is propagated well upstream of the rotor; temporal and spatial numerical resolution are fine enough such that attenuation of the signal is small. Two acoustic codes are used to find the far-field noise. Near-field propagation is computed by using Eversman's wave envelope code, which is based on a finite-element model. Propagation to the far field is accomplished by using the Kirchhoff formula for moving surfaces with the results of the wave envelope code as input data. Comparison of measured and computed far-field noise levels show fair agreement in the range of directivity angles where the peak radiation lobes from the inlet are observed. Although only a single acoustic mode is targeted in this study, the main conclusion is a proof-of-concept: Navier-Stokes codes can be used both to generate and propagate rotor/stator acoustic modes forward through an engine, where the results can be coupled to other far-field noise prediction codes.

Studying the influence of strong meteorological disturbances in the Earth's lower atmosphere on variations of ionospheric parameters in the Asian region of Russia

NASA Astrophysics Data System (ADS)

Chernigovskaya, Marina; Kurkin, Vladimir; Orlov, Igor; Oinats, Alexey; Sharkov, Eugenii

2010-05-01

Short-period temporal variations of ionospheric parameters were analyzed to study probabilities of manifestation of strong meteorological disturbances in the Earth's lower atmosphere in variations of upper atmosphere parameters in a zone far removed from a disturbance source. In the analysis, we used data on maximum observed frequencies (MOF) of oblique sounding (OS) signals along Norilsk-Irkutsk, Magadan-Irkutsk, and Khabarovsk-Irkutsk paths in East Siberia and the Far East. These data were obtained during solar minimum at equinoxes (March, September) in 2008-2009. Analyzing effects of wave disturbances in ionospheric parameters, we take into account helio-geomagnetic and meteorological conditions in regions under study to do an effective separation between disturbances associated with magnetospheric-ionospheric coupling and those induced by the influence of the lower atmosphere on the upper one. The frequency analysis we conducted revealed time intervals with higher intensity of short-period oscillations which may have been interpreted as manifestation of large-scale traveling ionospheric disturbances (TIDs) whose sources were internal gravity waves (IGWs) with periods of 1-5 hours. The complex analysis of helio-geomagnetic, ionospheric, and atmospheric data as well as data on tropical cyclones established that the detected TIDs were unrelated to helio-geomagnetic disturbances (2008-2009 exhibited solar minimum and quiet geomagnetic conditions). The analysis of other potential sources of the observed short-period wave disturbances shows that observed TIDs do not always coincide in time with passage of local meteorological fronts through the region of subionospheric points of OS paths and are not associated with passage of solar terminator. An attempt was made to connect a number of detected TIDs with ionospheric responses to tropical cyclones (TC) which were in active phase in the north-west of the Pacific Ocean during the periods considered. A considerable increase in energy of short-period wave disturbances was observed along Khabarovsk-Irkutsk, Magadan-Irkutsk, and Norilsk-Irkutsk paths during the active tropical cyclogenesis in September 2008-2009. Intensity of the observed TIDs decreased as midpoints of OS paths moved westward away from potential IGW sources. Ionospheric responses to wave disturbance propagation from the same IGW sources differ in the OS paths under analysis. This must be associated with different geometry of the OS paths as well as with the fact that the IGW source under consideration changes in intensity and its coordinates (stages and motion paths of tropical cyclones) during TC development. Thus there is an angular dependence between the wave disturbance propagation direction and the line connecting midpoints of the OS paths. Velocities of wave disturbance propagation (~90-170 m/s) were measured from the delay period of TIDs passage in regions of midpoints of spaced-apart OS paths. Short-period TIDs can also be observed at spring equinox in March 2008-2009 under quiet helio-geomagnetic conditions and in the absence of active tropical cyclones in the north-west of the Pacific Ocean, but TIDs energy is much lower than that in autumn. Authors note it was not possible to identify potential IGW sources for some TIDs within the scope of this work. These TIDs may be related to ionospheric responses to seasonal transitions in the upper atmosphere dynamic regime during the equinoxes under study. Further systematic investigations in this area of study are required to store statistics of observations of ionospheric responses to strong meteorological disturbances. The study was supported by the RFBR grant № 09-05-00760.

Centurion in Flight over Lakebed with STS Mate-DeMate Device in Background

NASA Technical Reports Server (NTRS)

1998-01-01

The Centurion remotely piloted flying wing in flight during an initial series of low-altitude, battery-powered test flights in late 1998 at NASA's Dryden Flight Research Center, Edwards, California. The special Mate-DeMate structure used by NASA to attach Space Shuttle orbiters to the back of modified Boeing 747s for transport to other locations can be seen in the background of this photo. Centurion was a unique remotely piloted, solar-powered airplane developed under NASA's Environmental Research Aircraft and Sensor (ERAST) Program at the Dryden Flight Research Center, Edwards, California. Dryden joined with AeroVironment, Inc., Monrovia, California, under an ERAST Joint Sponsored Research Agreement, to design, develop, manufacture, and conduct flight development tests for the Centurion. The airplane was believed to be the first aircraft designed to achieve sustained horizontal flight at altitudes of 90,000 to 100,000 feet. Achieving this capability would meet the ERAST goal of developing an ultrahigh-altitude airplane that could meet the needs of the science community to perform upper-atmosphere environmental data missions. Much of the technology leading to the Centurion was developed during the Pathfinder and Pathfinder-Plus projects. However, in the course of its development, the Centurion became a prototype technology demonstration aircraft designed to validate the technology for the Helios, a planned future high-altitude, solar-powered aircraft that could fly for weeks or months at a time on science or telecommunications missions. Centurion had 206-foot-long wings and used batteries to supply power to the craft's 14 electric motors and electronic systems. Centurion first flew at Dryden Nov. 10, 1998, and followed up with a second test flight Nov. 19. On its third and final flight on Dec. 3, the craft was aloft for 31 minutes and reached an altitude of about 400 feet. All three flights were conducted over a section of Rogers Dry Lake adjacent to Dryden. For its third flight, the Centurion carried a simulated payload of more than 600 pounds--almost half the lightweight aircraft's empty weight. John Del Frate, Dryden's project manager for solar-powered aircraft, said he was impressed to see how well the aircraft handled the large weight increase from an initial payload of 150 pounds to one of 600 pounds. During 1999, Centurion gave way to the Helios Prototype, the latest and largest example of a slow-flying ultralight flying wing designed for long-duration, high-altitude Earth science or telecommunications relay missions. This was an enlarged version of the Centurion flying wing with a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the solar-powered Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft. In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section and a fifth landing gear pod, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved its lifting capability. This allows the Helios Prototype to carry a regenerative fuel-cell-based energy storage system that will enable flight at night, while still meeting the performance goals originally established for the Centurion.

Development of advanced structural analysis methodologies for predicting widespread fatigue damage in aircraft structures

NASA Technical Reports Server (NTRS)

Harris, Charles E.; Starnes, James H., Jr.; Newman, James C., Jr.

1995-01-01

NASA is developing a 'tool box' that includes a number of advanced structural analysis computer codes which, taken together, represent the comprehensive fracture mechanics capability required to predict the onset of widespread fatigue damage. These structural analysis tools have complementary and specialized capabilities ranging from a finite-element-based stress-analysis code for two- and three-dimensional built-up structures with cracks to a fatigue and fracture analysis code that uses stress-intensity factors and material-property data found in 'look-up' tables or from equations. NASA is conducting critical experiments necessary to verify the predictive capabilities of the codes, and these tests represent a first step in the technology-validation and industry-acceptance processes. NASA has established cooperative programs with aircraft manufacturers to facilitate the comprehensive transfer of this technology by making these advanced structural analysis codes available to industry.

Analytical modeling of intumescent coating thermal protection system in a JP-5 fuel fire environment

NASA Technical Reports Server (NTRS)

Clark, K. J.; Shimizu, A. B.; Suchsland, K. E.; Moyer, C. B.

1974-01-01

The thermochemical response of Coating 313 when exposed to a fuel fire environment was studied to provide a tool for predicting the reaction time. The existing Aerotherm Charring Material Thermal Response and Ablation (CMA) computer program was modified to treat swelling materials. The modified code is now designated Aerotherm Transient Response of Intumescing Materials (TRIM) code. In addition, thermophysical property data for Coating 313 were analyzed and reduced for use in the TRIM code. An input data sensitivity study was performed, and performance tests of Coating 313/steel substrate models were carried out. The end product is a reliable computational model, the TRIM code, which was thoroughly validated for Coating 313. The tasks reported include: generation of input data, development of swell model and implementation in TRIM code, sensitivity study, acquisition of experimental data, comparisons of predictions with data, and predictions with intermediate insulation.

HART-II Acoustic Predictions using a Coupled CFD/CSD Method

NASA Technical Reports Server (NTRS)

Boyd, D. Douglas, Jr.

2009-01-01

This paper documents results to date from the Rotorcraft Acoustic Characterization and Mitigation activity under the NASA Subsonic Rotary Wing Project. The primary goal of this activity is to develop a NASA rotorcraft impulsive noise prediction capability which uses first principles fluid dynamics and structural dynamics. During this effort, elastic blade motion and co-processing capabilities have been included in a recent version of the computational fluid dynamics code (CFD). The CFD code is loosely coupled to computational structural dynamics (CSD) code using new interface codes. The CFD/CSD coupled solution is then used to compute impulsive noise on a plane under the rotor using the Ffowcs Williams-Hawkings solver. This code system is then applied to a range of cases from the Higher Harmonic Aeroacoustic Rotor Test II (HART-II) experiment. For all cases presented, the full experimental configuration (i.e., rotor and wind tunnel sting mount) are used in the coupled CFD/CSD solutions. Results show good correlation between measured and predicted loading and loading time derivative at the only measured radial station. A contributing factor for a typically seen loading mean-value offset between measured data and predictions data is examined. Impulsive noise predictions on the measured microphone plane under the rotor compare favorably with measured mid-frequency noise for all cases. Flow visualization of the BL and MN cases shows that vortex structures generated in the prediction method are consist with measurements. Future application of the prediction method is discussed.

Evaluation of Spanwise Variable Impedance Liners with Three-Dimensional Aeroacoustics Propagation Codes

NASA Technical Reports Server (NTRS)

Jones, M. G.; Watson, W. R.; Nark, D. M.; Schiller, N. H.

2017-01-01

Three perforate-over-honeycomb liner configurations, one uniform and two with spanwise variable impedance, are evaluated based on tests conducted in the NASA Grazing Flow Impedance Tube (GFIT) with a plane-wave source. Although the GFIT is only 2" wide, spanwise impedance variability clearly affects the measured acoustic pressure field, such that three-dimensional (3D) propagation codes are required to properly predict this acoustic pressure field. Three 3D propagation codes (CHE3D, COMSOL, and CDL) are used to predict the sound pressure level and phase at eighty-seven microphones flush-mounted in the GFIT (distributed along all four walls). The CHE3D and COMSOL codes compare favorably with the measured data, regardless of whether an exit acoustic pressure or anechoic boundary condition is employed. Except for those frequencies where the attenuation is large, the CDL code also provides acceptable estimates of the measured acoustic pressure profile. The CHE3D and COMSOL predictions diverge slightly from the measured data for frequencies away from resonance, where the attenuation is noticeably reduced, particularly when an exit acoustic pressure boundary condition is used. For these conditions, the CDL code actually provides slightly more favorable comparison with the measured data. Overall, the comparisons of predicted and measured data suggest that any of these codes can be used to understand data trends associated with spanwise variable-impedance liners.

New higher-order Godunov code for modelling performance of two-stage light gas guns

NASA Technical Reports Server (NTRS)

Bogdanoff, D. W.; Miller, R. J.

1995-01-01

A new quasi-one-dimensional Godunov code for modeling two-stage light gas guns is described. The code is third-order accurate in space and second-order accurate in time. A very accurate Riemann solver is used. Friction and heat transfer to the tube wall for gases and dense media are modeled and a simple nonequilibrium turbulence model is used for gas flows. The code also models gunpowder burn in the first-stage breech. Realistic equations of state (EOS) are used for all media. The code was validated against exact solutions of Riemann's shock-tube problem, impact of dense media slabs at velocities up to 20 km/sec, flow through a supersonic convergent-divergent nozzle and burning of gunpowder in a closed bomb. Excellent validation results were obtained. The code was then used to predict the performance of two light gas guns (1.5 in. and 0.28 in.) in service at the Ames Research Center. The code predictions were compared with measured pressure histories in the powder chamber and pump tube and with measured piston and projectile velocities. Very good agreement between computational fluid dynamics (CFD) predictions and measurements was obtained. Actual powder-burn rates in the gun were found to be considerably higher (60-90 percent) than predicted by the manufacturer and the behavior of the piston upon yielding appears to differ greatly from that suggested by low-strain rate tests.

Development of code evaluation criteria for assessing predictive capability and performance

NASA Technical Reports Server (NTRS)

Lin, Shyi-Jang; Barson, S. L.; Sindir, M. M.; Prueger, G. H.

1993-01-01

Computational Fluid Dynamics (CFD), because of its unique ability to predict complex three-dimensional flows, is being applied with increasing frequency in the aerospace industry. Currently, no consistent code validation procedure is applied within the industry. Such a procedure is needed to increase confidence in CFD and reduce risk in the use of these codes as a design and analysis tool. This final contract report defines classifications for three levels of code validation, directly relating the use of CFD codes to the engineering design cycle. Evaluation criteria by which codes are measured and classified are recommended and discussed. Criteria for selecting experimental data against which CFD results can be compared are outlined. A four phase CFD code validation procedure is described in detail. Finally, the code validation procedure is demonstrated through application of the REACT CFD code to a series of cases culminating in a code to data comparison on the Space Shuttle Main Engine High Pressure Fuel Turbopump Impeller.

NASA Lewis Stirling engine computer code evaluation

NASA Technical Reports Server (NTRS)

Sullivan, Timothy J.

1989-01-01

In support of the U.S. Department of Energy's Stirling Engine Highway Vehicle Systems program, the NASA Lewis Stirling engine performance code was evaluated by comparing code predictions without engine-specific calibration factors to GPU-3, P-40, and RE-1000 Stirling engine test data. The error in predicting power output was -11 percent for the P-40 and 12 percent for the Re-1000 at design conditions and 16 percent for the GPU-3 at near-design conditions (2000 rpm engine speed versus 3000 rpm at design). The efficiency and heat input predictions showed better agreement with engine test data than did the power predictions. Concerning all data points, the error in predicting the GPU-3 brake power was significantly larger than for the other engines and was mainly a result of inaccuracy in predicting the pressure phase angle. Analysis into this pressure phase angle prediction error suggested that improvements to the cylinder hysteresis loss model could have a significant effect on overall Stirling engine performance predictions.

Improved Helicopter Rotor Performance Prediction through Loose and Tight CFD/CSD Coupling

NASA Astrophysics Data System (ADS)

Ickes, Jacob C.

Helicopters and other Vertical Take-Off or Landing (VTOL) vehicles exhibit an interesting combination of structural dynamic and aerodynamic phenomena which together drive the rotor performance. The combination of factors involved make simulating the rotor a challenging and multidisciplinary effort, and one which is still an active area of interest in the industry because of the money and time it could save during design. Modern tools allow the prediction of rotorcraft physics from first principles. Analysis of the rotor system with this level of accuracy provides the understanding necessary to improve its performance. There has historically been a divide between the comprehensive codes which perform aeroelastic rotor simulations using simplified aerodynamic models, and the very computationally intensive Navier-Stokes Computational Fluid Dynamics (CFD) solvers. As computer resources become more available, efforts have been made to replace the simplified aerodynamics of the comprehensive codes with the more accurate results from a CFD code. The objective of this work is to perform aeroelastic rotorcraft analysis using first-principles simulations for both fluids and structural predictions using tools available at the University of Toledo. Two separate codes are coupled together in both loose coupling (data exchange on a periodic interval) and tight coupling (data exchange each time step) schemes. To allow the coupling to be carried out in a reliable and efficient way, a Fluid-Structure Interaction code was developed which automatically performs primary functions of loose and tight coupling procedures. Flow phenomena such as transonics, dynamic stall, locally reversed flow on a blade, and Blade-Vortex Interaction (BVI) were simulated in this work. Results of the analysis show aerodynamic load improvement due to the inclusion of the CFD-based airloads in the structural dynamics analysis of the Computational Structural Dynamics (CSD) code. Improvements came in the form of improved peak/trough magnitude prediction, better phase prediction of these locations, and a predicted signal with a frequency content more like the flight test data than the CSD code acting alone. Additionally, a tight coupling analysis was performed as a demonstration of the capability and unique aspects of such an analysis. This work shows that away from the center of the flight envelope, the aerodynamic modeling of the CSD code can be replaced with a more accurate set of predictions from a CFD code with an improvement in the aerodynamic results. The better predictions come at substantially increased computational costs between 1,000 and 10,000 processor-hours.

Open Rotor Noise Prediction Methods at NASA Langley- A Technology Review

NASA Technical Reports Server (NTRS)

Farassat, F.; Dunn, Mark H.; Tinetti, Ana F.; Nark, Douglas M.

2009-01-01

Open rotors are once again under consideration for propulsion of the future airliners because of their high efficiency. The noise generated by these propulsion systems must meet the stringent noise standards of today to reduce community impact. In this paper we review the open rotor noise prediction methods available at NASA Langley. We discuss three codes called ASSPIN (Advanced Subsonic-Supersonic Propeller Induced Noise), FW - Hpds (Ffowcs Williams-Hawkings with penetrable data surface) and the FSC (Fast Scattering Code). The first two codes are in the time domain and the third code is a frequency domain code. The capabilities of these codes and the input data requirements as well as the output data are presented. Plans for further improvements of these codes are discussed. In particular, a method based on equivalent sources is outlined to get rid of spurious signals in the FW - Hpds code.

Quasi-steady solar wind dynamics

NASA Technical Reports Server (NTRS)

Pizzo, V. J.

1983-01-01

Progress in understanding the large scale dynamics of quasisteady, corotating solar wind structure was reviewed. The nature of the solar wind at large heliocentric distances preliminary calculations from a 2-D MHD model are used to demonstrate theoretical expectations of corotating structure out to 30 AU. It is found that the forward and reverse shocks from adjacent CIR's begin to interact at about 10 AU, producing new shock pairs flanking secondary CIR's. These sawtooth secondary CIR's interact again at about 20 AU and survive as visible entities to 30 AU. The model predicts the velocity jumps at the leading edge of the secondary CIR's at 30 AU should be very small but there should still be sizable variations in the thermodynamic and magnetic parameters. The driving dynamic mechanism in the distant solar wind is the relaxation of pressure gradients. The second topic is the influence of weak, nonimpulsive time dependence in quasisteady dynamics. It is suggested that modest large scale variations in the coronal flow speed on periods of several hours to a day may be responsible for many of the remaining discrepancies between theory and observation. Effects offer a ready explanation for the apparent rounding of stream fronts between 0.3 and 1.0 AU discovered by Helios.

The Effect of Inhomogeneities on High-Frequency, Low-1 p-Modes: DIFOS Experiment on CORONAS-I

NASA Technical Reports Server (NTRS)

Kalkofen, Wolfgang

1998-01-01

The investigation of the effects of inhomogeneities of the acoustic modes of the global solar oscillation spectrum has two parts, the first dealing with the prediction of wave fluxes in magnetic flux tubes due to the excitation of longitudinal (i.e. pressure) modes, and the second part, concerning the effects of radiation damping on the p-modes themselves. Part 1 of this work, in collaboration with S.S. Hasan (Indian Institute of Astro- physics, Bangalore), is complete and has resulted in a publication titled Excitation of Longitudinal Modes in Solar Magnetic Flux Tubes, By S.S. Hasan & WK. It is in press in the ASP conference series, containing the proceedings of the Cool Stars conference of 1997, R.A. Donahue and J.A. Bookbinder, editors; publication is expected in 1998. Part 2, in collaboration with Y. Zhugzhda (Izmiran, Moscow) and J. Staude (Sonnenobservatorium Einsteinturm, Potsdam) is in progress and is expected to result in a paper in the forthcoming Boston conference on Helio- and Asteroseismology in June, 1998. A fuller accounting of the work done under the grant will be given when the work started with funding from the grant is complete.

Protons and alpha particles in the expanding solar wind: Hybrid simulations

NASA Astrophysics Data System (ADS)

Hellinger, Petr; Trávníček, Pavel M.

2013-09-01

We present results of a two‒dimensional hybrid expanding box simulation of a plasma system with three ion populations, beam and core protons, and alpha particles (and fluid electrons), drifting with respect to each other. The expansion with a strictly radial magnetic field leads to a decrease of the ion perpendicular to parallel temperature ratios as well as to an increase of the ratio between the ion relative velocities and the local Alfvén velocity creating a free energy for many different instabilities. The system is most of the time marginally stable with respect to kinetic instabilities mainly due to the ion relative velocities; these instabilities determine the system evolution counteracting some effects of the expansion. Nonlinear evolution of these instabilities leads to large modifications of the ion velocity distribution functions. The beam protons and alpha particles are decelerated with respect to the core protons and all the populations are cooled in the parallel direction and heated in the perpendicular one. On the macroscopic level, the kinetic instabilities cause large departures of the system evolution from the double adiabatic prediction and lead to perpendicular heating and parallel cooling rates which are comparable to the heating rates estimated from the Helios observations.

Using Near Space Vehicles in the Pursuit of Persistent C3ISR

DTIC Science & Technology

2005-06-01

point are unmanned. Even so, this paper defines UAVs as aircraft. This section summarizes the Global Hawk, Theseus , Proteus, and Helios, which...reduced altitude and endurance.85 Theseus , built by Aurora Flight Sciences, is a moderately capable HALE. A traditional Honeywell TPE331-14F turboprop...propels the 7,900 lb aircraft up to 60,000 ft (just below near space). Theseus generates 6 kVa to power up to 1,800 lbs of sensors. Two

Contributions to the Fourth Solar Wind Conference. [interplanetary magnetic fields and medium

NASA Technical Reports Server (NTRS)

Acuna, M. H.; Behannon, K. W.; Burlaga, L. F.; Lepping, R.; Ness, N.; Ogilvie, K.; Pizzo, J.

1979-01-01

Recent results in interplanetary physics are examined. These include observations of shock waves and post-shock magnetic fields made by Voyager 1, 2; observations of the electron temperature as a function of distance between 1.36 AU and 2.25 AU; and observations of the structure of sector boundaries observed by Helios 1. A theory of electron energy transport in the collisionless solar wind is presented, and compared with observations. Alfven waves and Alvenic fluctuations in the solar wind are also discussed.

The Goddard program of gamma ray transient astronomy

NASA Technical Reports Server (NTRS)

Cline, T. L.; Desai, U. D.; Teegarden, B. J.

1980-01-01

Gamma ray burst studies are reviewed. The past results, present status and future expectations are outlined regarding endeavors using experiments on balloons, IMP-6 and -7, OGO-3, ISEE-1 and -3, Helios-2, Solar Maximum Mission, the Einstein Observatory, Solar Polar and the Gamma Ray Observatory, and with the interplanetary gamma ray burst networks, to which some of these spacecraft sensors contribute. Additional emphasis is given to the recent discovery of a new type of gamma ray transient, detected on 1979 March 5.

Peak-Flux-Density Spectra of Large Solar Radio Bursts and Proton Emission from Flares.

DTIC Science & Technology

1985-08-19

of the microwave peak (Z 1000 sfu in U-bursts) served as an indicator that the energy release during the impulsive phase was sufficient to produce a... energy or wave- length tends to be prominent in all, and cautions about over-interpreting associa- tions/correlations observed in samples of big flares...Sung, L. S., and McDonald, F. B. (1975) The variation of solar proton energy spectra and size distribution with helio- longitude, Sol. Phys. 41: 189. 28

Transcription Factor Binding Profiles Reveal Cyclic Expression of Human Protein-coding Genes and Non-coding RNAs

PubMed Central

Cheng, Chao; Ung, Matthew; Grant, Gavin D.; Whitfield, Michael L.

2013-01-01

Cell cycle is a complex and highly supervised process that must proceed with regulatory precision to achieve successful cellular division. Despite the wide application, microarray time course experiments have several limitations in identifying cell cycle genes. We thus propose a computational model to predict human cell cycle genes based on transcription factor (TF) binding and regulatory motif information in their promoters. We utilize ENCODE ChIP-seq data and motif information as predictors to discriminate cell cycle against non-cell cycle genes. Our results show that both the trans- TF features and the cis- motif features are predictive of cell cycle genes, and a combination of the two types of features can further improve prediction accuracy. We apply our model to a complete list of GENCODE promoters to predict novel cell cycle driving promoters for both protein-coding genes and non-coding RNAs such as lincRNAs. We find that a similar percentage of lincRNAs are cell cycle regulated as protein-coding genes, suggesting the importance of non-coding RNAs in cell cycle division. The model we propose here provides not only a practical tool for identifying novel cell cycle genes with high accuracy, but also new insights on cell cycle regulation by TFs and cis-regulatory elements. PMID:23874175

Real coded genetic algorithm for fuzzy time series prediction

NASA Astrophysics Data System (ADS)

Jain, Shilpa; Bisht, Dinesh C. S.; Singh, Phool; Mathpal, Prakash C.

2017-10-01

Genetic Algorithm (GA) forms a subset of evolutionary computing, rapidly growing area of Artificial Intelligence (A.I.). Some variants of GA are binary GA, real GA, messy GA, micro GA, saw tooth GA, differential evolution GA. This research article presents a real coded GA for predicting enrollments of University of Alabama. Data of Alabama University is a fuzzy time series. Here, fuzzy logic is used to predict enrollments of Alabama University and genetic algorithm optimizes fuzzy intervals. Results are compared to other eminent author works and found satisfactory, and states that real coded GA are fast and accurate.

Computer program for prediction of the deposition of material released from fixed and rotary wing aircraft

NASA Technical Reports Server (NTRS)

Teske, M. E.

1984-01-01

This is a user manual for the computer code ""AGDISP'' (AGricultural DISPersal) which has been developed to predict the deposition of material released from fixed and rotary wing aircraft in a single-pass, computationally efficient manner. The formulation of the code is novel in that the mean particle trajectory and the variance about the mean resulting from turbulent fluid fluctuations are simultaneously predicted. The code presently includes the capability of assessing the influence of neutral atmospheric conditions, inviscid wake vortices, particle evaporation, plant canopy and terrain on the deposition pattern.

Prediction of the Reactor Antineutrino Flux for the Double Chooz Experiment

NASA Astrophysics Data System (ADS)

Jones, Chirstopher LaDon

This thesis benchmarks the deterministic lattice code, DRAGON, against data, and then applies this code to make a prediction for the antineutrino flux from the Chooz Bl and B2 reactors. Data from the destructive assay of rods from the Takahama-3 reactor and from the SONGS antineutrino detector are used for comparisons. The resulting prediction from the tuned DRAGON code is then compared to the first antineutrino event spectra from Double Chooz. Use of this simulation in nuclear nonproliferation studies is discussed. (Copies available exclusively from MIT Libraries, libraries.mit.edu/docs - docs@mit.edu)

An Assessment of Current Fan Noise Prediction Capability

NASA Technical Reports Server (NTRS)

Envia, Edmane; Woodward, Richard P.; Elliott, David M.; Fite, E. Brian; Hughes, Christopher E.; Podboy, Gary G.; Sutliff, Daniel L.

2008-01-01

In this paper, the results of an extensive assessment exercise carried out to establish the current state of the art for predicting fan noise at NASA are presented. Representative codes in the empirical, analytical, and computational categories were exercised and assessed against a set of benchmark acoustic data obtained from wind tunnel tests of three model scale fans. The chosen codes were ANOPP, representing an empirical capability, RSI, representing an analytical capability, and LINFLUX, representing a computational aeroacoustics capability. The selected benchmark fans cover a wide range of fan pressure ratios and fan tip speeds, and are representative of modern turbofan engine designs. The assessment results indicate that the ANOPP code can predict fan noise spectrum to within 4 dB of the measurement uncertainty band on a third-octave basis for the low and moderate tip speed fans except at extreme aft emission angles. The RSI code can predict fan broadband noise spectrum to within 1.5 dB of experimental uncertainty band provided the rotor-only contribution is taken into account. The LINFLUX code can predict interaction tone power levels to within experimental uncertainties at low and moderate fan tip speeds, but could deviate by as much as 6.5 dB outside the experimental uncertainty band at the highest tip speeds in some case.

The Design and Implementation of a Read Prediction Buffer

DTIC Science & Technology

1992-12-01

City, State, and ZIP Code) 7b ADDRESS (City, State. and ZIP Code) 8a. NAME OF FUNDING /SPONSORING 8b. OFFICE SYMBOL 9 PROCUREMENT INSTRUMENT... 9 E. THESIS STRUCTURE.. . .... ............... 9 II. READ PREDICTION ALGORITHM AND BUFFER DESIGN 10 A. THE READ PREDICTION ALGORITHM...29 Figure 9 . Basic Multiplexer Cell .... .......... .. 30 Figure 10. Block Diagram Simulation Labels ......... 38 viii I. INTRODUCTION A

Adapting hierarchical bidirectional inter prediction on a GPU-based platform for 2D and 3D H.264 video coding

NASA Astrophysics Data System (ADS)

Rodríguez-Sánchez, Rafael; Martínez, José Luis; Cock, Jan De; Fernández-Escribano, Gerardo; Pieters, Bart; Sánchez, José L.; Claver, José M.; de Walle, Rik Van

2013-12-01

The H.264/AVC video coding standard introduces some improved tools in order to increase compression efficiency. Moreover, the multi-view extension of H.264/AVC, called H.264/MVC, adopts many of them. Among the new features, variable block-size motion estimation is one which contributes to high coding efficiency. Furthermore, it defines a different prediction structure that includes hierarchical bidirectional pictures, outperforming traditional Group of Pictures patterns in both scenarios: single-view and multi-view. However, these video coding techniques have high computational complexity. Several techniques have been proposed in the literature over the last few years which are aimed at accelerating the inter prediction process, but there are no works focusing on bidirectional prediction or hierarchical prediction. In this article, with the emergence of many-core processors or accelerators, a step forward is taken towards an implementation of an H.264/AVC and H.264/MVC inter prediction algorithm on a graphics processing unit. The results show a negligible rate distortion drop with a time reduction of up to 98% for the complete H.264/AVC encoder.

Grid-Adapted FUN3D Computations for the Second High Lift Prediction Workshop

NASA Technical Reports Server (NTRS)

Lee-Rausch, E. M.; Rumsey, C. L.; Park, M. A.

2014-01-01

Contributions of the unstructured Reynolds-averaged Navier-Stokes code FUN3D to the 2nd AIAA CFD High Lift Prediction Workshop are described, and detailed comparisons are made with experimental data. Using workshop-supplied grids, results for the clean wing configuration are compared with results from the structured code CFL3D Using the same turbulence model, both codes compare reasonably well in terms of total forces and moments, and the maximum lift is similarly over-predicted for both codes compared to experiment. By including more representative geometry features such as slat and flap brackets and slat pressure tube bundles, FUN3D captures the general effects of the Reynolds number variation, but under-predicts maximum lift on workshop-supplied grids in comparison with the experimental data, due to excessive separation. However, when output-based, off-body grid adaptation in FUN3D is employed, results improve considerably. In particular, when the geometry includes both brackets and the pressure tube bundles, grid adaptation results in a more accurate prediction of lift near stall in comparison with the wind-tunnel data. Furthermore, a rotation-corrected turbulence model shows improved pressure predictions on the outboard span when using adapted grids.

Contrasting Five Different Theories of Letter Position Coding: Evidence from Orthographic Similarity Effects

ERIC Educational Resources Information Center

Davis, Colin J.; Bowers, Jeffrey S.

2006-01-01

Five theories of how letter position is coded are contrasted: position-specific slot-coding, Wickelcoding, open-bigram coding (discrete and continuous), and spatial coding. These theories make different predictions regarding the relative similarity of three different types of pairs of letter strings: substitution neighbors,…

Comparison of Predicted and Measured Attenuation of Turbine Noise from a Static Engine Test

NASA Technical Reports Server (NTRS)

Chien, Eugene W.; Ruiz, Marta; Yu, Jia; Morin, Bruce L.; Cicon, Dennis; Schwieger, Paul S.; Nark, Douglas M.

2007-01-01

Aircraft noise has become an increasing concern for commercial airlines. Worldwide demand for quieter aircraft is increasing, making the prediction of engine noise suppression one of the most important fields of research. The Low-Pressure Turbine (LPT) can be an important noise source during the approach condition for commercial aircraft. The National Aeronautics and Space Administration (NASA), Pratt & Whitney (P&W), and Goodrich Aerostructures (Goodrich) conducted a joint program to validate a method for predicting turbine noise attenuation. The method includes noise-source estimation, acoustic treatment impedance prediction, and in-duct noise propagation analysis. Two noise propagation prediction codes, Eversman Finite Element Method (FEM) code [1] and the CDUCT-LaRC [2] code, were used in this study to compare the predicted and the measured turbine noise attenuation from a static engine test. In this paper, the test setup, test configurations and test results are detailed in Section II. A description of the input parameters, including estimated noise modal content (in terms of acoustic potential), and acoustic treatment impedance values are provided in Section III. The prediction-to-test correlation study results are illustrated and discussed in Section IV and V for the FEM and the CDUCT-LaRC codes, respectively, and a summary of the results is presented in Section VI.

Prediction of Acoustic Loads Generated by Propulsion Systems

NASA Technical Reports Server (NTRS)

Perez, Linamaria; Allgood, Daniel C.

2011-01-01

NASA Stennis Space Center is one of the nation's premier facilities for conducting large-scale rocket engine testing. As liquid rocket engines vary in size, so do the acoustic loads that they produce. When these acoustic loads reach very high levels they may cause damages both to humans and to actual structures surrounding the testing area. To prevent these damages, prediction tools are used to estimate the spectral content and levels of the acoustics being generated by the rocket engine plumes and model their propagation through the surrounding atmosphere. Prior to the current work, two different acoustic prediction tools were being implemented at Stennis Space Center, each having their own advantages and disadvantages depending on the application. Therefore, a new prediction tool was created, using NASA SP-8072 handbook as a guide, which would replicate the same prediction methods as the previous codes, but eliminate any of the drawbacks the individual codes had. Aside from replicating the previous modeling capability in a single framework, additional modeling functions were added thereby expanding the current modeling capability. To verify that the new code could reproduce the same predictions as the previous codes, two verification test cases were defined. These verification test cases also served as validation cases as the predicted results were compared to actual test data.

Euler Technology Assessment for Preliminary Aircraft Design: Compressibility Predictions by Employing the Cartesian Unstructured Grid SPLITFLOW Code

NASA Technical Reports Server (NTRS)

Finley, Dennis B.; Karman, Steve L., Jr.

1996-01-01

The objective of the second phase of the Euler Technology Assessment program was to evaluate the ability of Euler computational fluid dynamics codes to predict compressible flow effects over a generic fighter wind tunnel model. This portion of the study was conducted by Lockheed Martin Tactical Aircraft Systems, using an in-house Cartesian-grid code called SPLITFLOW. The Cartesian grid technique offers several advantages, including ease of volume grid generation and reduced number of cells compared to other grid schemes. SPLITFLOW also includes grid adaption of the volume grid during the solution to resolve high-gradient regions. The SPLITFLOW code predictions of configuration forces and moments are shown to be adequate for preliminary design, including predictions of sideslip effects and the effects of geometry variations at low and high angles-of-attack. The transonic pressure prediction capabilities of SPLITFLOW are shown to be improved over subsonic comparisons. The time required to generate the results from initial surface data is on the order of several hours, including grid generation, which is compatible with the needs of the design environment.

Statistical Analysis of CFD Solutions from 2nd Drag Prediction Workshop

NASA Technical Reports Server (NTRS)

Hemsch, M. J.; Morrison, J. H.

2004-01-01

In June 2001, the first AIAA Drag Prediction Workshop was held to evaluate results obtained from extensive N-Version testing of a series of RANS CFD codes. The geometry used for the computations was the DLR-F4 wing-body combination which resembles a medium-range subsonic transport. The cases reported include the design cruise point, drag polars at eight Mach numbers, and drag rise at three values of lift. Although comparisons of the code-to-code medians with available experimental data were similar to those obtained in previous studies, the code-to-code scatter was more than an order-of-magnitude larger than expected and far larger than desired for design and for experimental validation. The second Drag Prediction Workshop was held in June 2003 with emphasis on the determination of installed pylon-nacelle drag increments and on grid refinement studies. The geometry used was the DLR-F6 wing-body-pylon-nacelle combination for which the design cruise point and the cases run were similar to the first workshop except for additional runs on coarse and fine grids to complement the runs on medium grids. The code-to-code scatter was significantly reduced for the wing-body configuration compared to the first workshop, although still much larger than desired. However, the grid refinement studies showed no sign$cant improvement in code-to-code scatter with increasing grid refinement.

Dopamine Modulates Adaptive Prediction Error Coding in the Human Midbrain and Striatum.

PubMed

Diederen, Kelly M J; Ziauddeen, Hisham; Vestergaard, Martin D; Spencer, Tom; Schultz, Wolfram; Fletcher, Paul C

2017-02-15

Learning to optimally predict rewards requires agents to account for fluctuations in reward value. Recent work suggests that individuals can efficiently learn about variable rewards through adaptation of the learning rate, and coding of prediction errors relative to reward variability. Such adaptive coding has been linked to midbrain dopamine neurons in nonhuman primates, and evidence in support for a similar role of the dopaminergic system in humans is emerging from fMRI data. Here, we sought to investigate the effect of dopaminergic perturbations on adaptive prediction error coding in humans, using a between-subject, placebo-controlled pharmacological fMRI study with a dopaminergic agonist (bromocriptine) and antagonist (sulpiride). Participants performed a previously validated task in which they predicted the magnitude of upcoming rewards drawn from distributions with varying SDs. After each prediction, participants received a reward, yielding trial-by-trial prediction errors. Under placebo, we replicated previous observations of adaptive coding in the midbrain and ventral striatum. Treatment with sulpiride attenuated adaptive coding in both midbrain and ventral striatum, and was associated with a decrease in performance, whereas bromocriptine did not have a significant impact. Although we observed no differential effect of SD on performance between the groups, computational modeling suggested decreased behavioral adaptation in the sulpiride group. These results suggest that normal dopaminergic function is critical for adaptive prediction error coding, a key property of the brain thought to facilitate efficient learning in variable environments. Crucially, these results also offer potential insights for understanding the impact of disrupted dopamine function in mental illness. SIGNIFICANCE STATEMENT To choose optimally, we have to learn what to expect. Humans dampen learning when there is a great deal of variability in reward outcome, and two brain regions that are modulated by the brain chemical dopamine are sensitive to reward variability. Here, we aimed to directly relate dopamine to learning about variable rewards, and the neural encoding of associated teaching signals. We perturbed dopamine in healthy individuals using dopaminergic medication and asked them to predict variable rewards while we made brain scans. Dopamine perturbations impaired learning and the neural encoding of reward variability, thus establishing a direct link between dopamine and adaptation to reward variability. These results aid our understanding of clinical conditions associated with dopaminergic dysfunction, such as psychosis. Copyright © 2017 Diederen et al.

Is phonology bypassed in normal or dyslexic development?

PubMed

Pennington, B F; Lefly, D L; Van Orden, G C; Bookman, M O; Smith, S D

1987-01-01

A pervasive assumption in most accounts of normal reading and spelling development is that phonological coding is important early in development but is subsequently superseded by faster, orthographic coding which bypasses phonology. We call this assumption, which derives from dual process theory, the developmental bypass hypothesis. The present study tests four specific predictions of the developmental bypass hypothesis by comparing dyslexics and nondyslexics from the same families in a cross-sectional design. The four predictions are: 1) That phonological coding skill develops early in normal readers and soon reaches asymptote, whereas orthographic coding skill has a protracted course of development; 2) that the correlation of adult reading or spelling performance with phonological coding skill is considerably less than the correlation with orthographic coding skill; 3) that dyslexics who are mainly deficient in phonological coding skill should be able to bypass this deficit and eventually close the gap in reading and spelling performance; and 4) that the greatest differences between dyslexics and developmental controls on measures of phonological coding skill should be observed early rather than late in development.None of the four predictions of the developmental bypass hypothesis were upheld. Phonological coding skill continued to develop in nondyslexics until adulthood. It accounted for a substantial (32-53 percent) portion of the variance in reading and spelling performance in adult nondyslexics, whereas orthographic coding skill did not account for a statistically reliable portion of this variance. The dyslexics differed little across age in phonological coding skill, but made linear progress in orthographic coding skill, surpassing spelling-age (SA) controls by adulthood. Nonetheless, they didnot close the gap in reading and spelling performance. Finally, dyslexics were significantly worse than SA (and Reading Age [RA]) controls in phonological coding skill only in adulthood.

Computation of Sound Generated by Flow Over a Circular Cylinder: An Acoustic Analogy Approach

NASA Technical Reports Server (NTRS)

Brentner, Kenneth S.; Cox, Jared S.; Rumsey, Christopher L.; Younis, Bassam A.

1997-01-01

The sound generated by viscous flow past a circular cylinder is predicted via the Lighthill acoustic analogy approach. The two dimensional flow field is predicted using two unsteady Reynolds-averaged Navier-Stokes solvers. Flow field computations are made for laminar flow at three Reynolds numbers (Re = 1000, Re = 10,000, and Re = 90,000) and two different turbulent models at Re = 90,000. The unsteady surface pressures are utilized by an acoustics code that implements Farassat's formulation 1A to predict the acoustic field. The acoustic code is a 3-D code - 2-D results are found by using a long cylinder length. The 2-D predictions overpredict the acoustic amplitude; however, if correlation lengths in the range of 3 to 10 cylinder diameters are used, the predicted acoustic amplitude agrees well with experiment.

High-Level Prediction Signals in a Low-Level Area of the Macaque Face-Processing Hierarchy.

PubMed

Schwiedrzik, Caspar M; Freiwald, Winrich A

2017-09-27

Theories like predictive coding propose that lower-order brain areas compare their inputs to predictions derived from higher-order representations and signal their deviation as a prediction error. Here, we investigate whether the macaque face-processing system, a three-level hierarchy in the ventral stream, employs such a coding strategy. We show that after statistical learning of specific face sequences, the lower-level face area ML computes the deviation of actual from predicted stimuli. But these signals do not reflect the tuning characteristic of ML. Rather, they exhibit identity specificity and view invariance, the tuning properties of higher-level face areas AL and AM. Thus, learning appears to endow lower-level areas with the capability to test predictions at a higher level of abstraction than what is afforded by the feedforward sweep. These results provide evidence for computational architectures like predictive coding and suggest a new quality of functional organization of information-processing hierarchies beyond pure feedforward schemes. Copyright © 2017 Elsevier Inc. All rights reserved.

A Measurement and Simulation Based Methodology for Cache Performance Modeling and Tuning

NASA Technical Reports Server (NTRS)

Waheed, Abdul; Yan, Jerry; Saini, Subhash (Technical Monitor)

1998-01-01

We present a cache performance modeling methodology that facilitates the tuning of uniprocessor cache performance for applications executing on shared memory multiprocessors by accurately predicting the effects of source code level modifications. Measurements on a single processor are initially used for identifying parts of code where cache utilization improvements may significantly impact the overall performance. Cache simulation based on trace-driven techniques can be carried out without gathering detailed address traces. Minimal runtime information for modeling cache performance of a selected code block includes: base virtual addresses of arrays, virtual addresses of variables, and loop bounds for that code block. Rest of the information is obtained from the source code. We show that the cache performance predictions are as reliable as those obtained through trace-driven simulations. This technique is particularly helpful to the exploration of various "what-if' scenarios regarding the cache performance impact for alternative code structures. We explain and validate this methodology using a simple matrix-matrix multiplication program. We then apply this methodology to predict and tune the cache performance of two realistic scientific applications taken from the Computational Fluid Dynamics (CFD) domain.

Three-dimensional turbopump flowfield analysis

NASA Technical Reports Server (NTRS)

Sharma, O. P.; Belford, K. A.; Ni, R. H.

1992-01-01

A program was conducted to develop a flow prediction method applicable to rocket turbopumps. The complex nature of a flowfield in turbopumps is described and examples of flowfields are discussed to illustrate that physics based models and analytical calculation procedures based on computational fluid dynamics (CFD) are needed to develop reliable design procedures for turbopumps. A CFD code developed at NASA ARC was used as the base code. The turbulence model and boundary conditions in the base code were modified, respectively, to: (1) compute transitional flows and account for extra rates of strain, e.g., rotation; and (2) compute surface heat transfer coefficients and allow computation through multistage turbomachines. Benchmark quality data from two and three-dimensional cascades were used to verify the code. The predictive capabilities of the present CFD code were demonstrated by computing the flow through a radial impeller and a multistage axial flow turbine. Results of the program indicate that the present code operated in a two-dimensional mode is a cost effective alternative to full three-dimensional calculations, and that it permits realistic predictions of unsteady loadings and losses for multistage machines.

Off-design computer code for calculating the aerodynamic performance of axial-flow fans and compressors

NASA Technical Reports Server (NTRS)

Schmidt, James F.

1995-01-01

An off-design axial-flow compressor code is presented and is available from COSMIC for predicting the aerodynamic performance maps of fans and compressors. Steady axisymmetric flow is assumed and the aerodynamic solution reduces to solving the two-dimensional flow field in the meridional plane. A streamline curvature method is used for calculating this flow-field outside the blade rows. This code allows for bleed flows and the first five stators can be reset for each rotational speed, capabilities which are necessary for large multistage compressors. The accuracy of the off-design performance predictions depend upon the validity of the flow loss and deviation correlation models. These empirical correlations for the flow loss and deviation are used to model the real flow effects and the off-design code will compute through small reverse flow regions. The input to this off-design code is fully described and a user's example case for a two-stage fan is included with complete input and output data sets. Also, a comparison of the off-design code predictions with experimental data is included which generally shows good agreement.

Decision-making in schizophrenia: A predictive-coding perspective.

PubMed

Sterzer, Philipp; Voss, Martin; Schlagenhauf, Florian; Heinz, Andreas

2018-05-31

Dysfunctional decision-making has been implicated in the positive and negative symptoms of schizophrenia. Decision-making can be conceptualized within the framework of hierarchical predictive coding as the result of a Bayesian inference process that uses prior beliefs to infer states of the world. According to this idea, prior beliefs encoded at higher levels in the brain are fed back as predictive signals to lower levels. Whenever these predictions are violated by the incoming sensory data, a prediction error is generated and fed forward to update beliefs encoded at higher levels. Well-documented impairments in cognitive decision-making support the view that these neural inference mechanisms are altered in schizophrenia. There is also extensive evidence relating the symptoms of schizophrenia to aberrant signaling of prediction errors, especially in the domain of reward and value-based decision-making. Moreover, the idea of altered predictive coding is supported by evidence for impaired low-level sensory mechanisms and motor processes. We review behavioral and neural findings from these research areas and provide an integrated view suggesting that schizophrenia may be related to a pervasive alteration in predictive coding at multiple hierarchical levels, including cognitive and value-based decision-making processes as well as sensory and motor systems. We relate these findings to decision-making processes and propose that varying degrees of impairment in the implicated brain areas contribute to the variety of psychotic experiences. Copyright © 2018 Elsevier Inc. All rights reserved.

Illusory Motion Reproduced by Deep Neural Networks Trained for Prediction

PubMed Central

Watanabe, Eiji; Kitaoka, Akiyoshi; Sakamoto, Kiwako; Yasugi, Masaki; Tanaka, Kenta

2018-01-01

The cerebral cortex predicts visual motion to adapt human behavior to surrounding objects moving in real time. Although the underlying mechanisms are still unknown, predictive coding is one of the leading theories. Predictive coding assumes that the brain's internal models (which are acquired through learning) predict the visual world at all times and that errors between the prediction and the actual sensory input further refine the internal models. In the past year, deep neural networks based on predictive coding were reported for a video prediction machine called PredNet. If the theory substantially reproduces the visual information processing of the cerebral cortex, then PredNet can be expected to represent the human visual perception of motion. In this study, PredNet was trained with natural scene videos of the self-motion of the viewer, and the motion prediction ability of the obtained computer model was verified using unlearned videos. We found that the computer model accurately predicted the magnitude and direction of motion of a rotating propeller in unlearned videos. Surprisingly, it also represented the rotational motion for illusion images that were not moving physically, much like human visual perception. While the trained network accurately reproduced the direction of illusory rotation, it did not detect motion components in negative control pictures wherein people do not perceive illusory motion. This research supports the exciting idea that the mechanism assumed by the predictive coding theory is one of basis of motion illusion generation. Using sensory illusions as indicators of human perception, deep neural networks are expected to contribute significantly to the development of brain research. PMID:29599739

Illusory Motion Reproduced by Deep Neural Networks Trained for Prediction.

PubMed

Watanabe, Eiji; Kitaoka, Akiyoshi; Sakamoto, Kiwako; Yasugi, Masaki; Tanaka, Kenta

2018-01-01

The cerebral cortex predicts visual motion to adapt human behavior to surrounding objects moving in real time. Although the underlying mechanisms are still unknown, predictive coding is one of the leading theories. Predictive coding assumes that the brain's internal models (which are acquired through learning) predict the visual world at all times and that errors between the prediction and the actual sensory input further refine the internal models. In the past year, deep neural networks based on predictive coding were reported for a video prediction machine called PredNet. If the theory substantially reproduces the visual information processing of the cerebral cortex, then PredNet can be expected to represent the human visual perception of motion. In this study, PredNet was trained with natural scene videos of the self-motion of the viewer, and the motion prediction ability of the obtained computer model was verified using unlearned videos. We found that the computer model accurately predicted the magnitude and direction of motion of a rotating propeller in unlearned videos. Surprisingly, it also represented the rotational motion for illusion images that were not moving physically, much like human visual perception. While the trained network accurately reproduced the direction of illusory rotation, it did not detect motion components in negative control pictures wherein people do not perceive illusory motion. This research supports the exciting idea that the mechanism assumed by the predictive coding theory is one of basis of motion illusion generation. Using sensory illusions as indicators of human perception, deep neural networks are expected to contribute significantly to the development of brain research.

Security Concepts for Satellite Links

NASA Astrophysics Data System (ADS)

Tobehn, C.; Penné, B.; Rathje, R.; Weigl, A.; Gorecki, Ch.; Michalik, H.

2008-08-01

The high costs to develop, launch and maintain a satellite network makes protecting the assets imperative. Attacks may be passive such as eavesdropping on the payload data. More serious threat are active attacks that try to gain control of the satellite, which may lead to the total lost of the satellite asset. To counter these threats, new satellite and ground systems are using cryptographic technologies to provide a range of services: confidentiality, entity & message authentication, and data integrity. Additionally, key management cryptographic services are required to support these services. This paper describes the key points of current satellite control and operations, that are authentication of the access to the satellite TMTC link and encryption of security relevant TM/TC data. For payload data management the key points are multi-user ground station access and high data rates both requiring frequent updates and uploads of keys with the corresponding key management methods. For secure satellite management authentication & key negotiation algorithms as HMAC-RIPEMD160, EC- DSA and EC-DH are used. Encryption of data uses algorithms as IDEA, AES, Triple-DES, or other. A channel coding and encryption unit for payload data provides download data rates up to Nx250 Mbps. The presented concepts are based on our experience and heritage of the security systems for all German MOD satellite projects (SATCOMBw2, SAR-Lupe multi- satellite system and German-French SAR-Lupe-Helios- II systems inter-operability) as well as for further international (KOMPSAT-II Payload data link system) and ESA activities (TMTC security and GMES).

FUN3D and CFL3D Computations for the First High Lift Prediction Workshop

NASA Technical Reports Server (NTRS)

Park, Michael A.; Lee-Rausch, Elizabeth M.; Rumsey, Christopher L.

2011-01-01

Two Reynolds-averaged Navier-Stokes codes were used to compute flow over the NASA Trapezoidal Wing at high lift conditions for the 1st AIAA CFD High Lift Prediction Workshop, held in Chicago in June 2010. The unstructured-grid code FUN3D and the structured-grid code CFL3D were applied to several different grid systems. The effects of code, grid system, turbulence model, viscous term treatment, and brackets were studied. The SST model on this configuration predicted lower lift than the Spalart-Allmaras model at high angles of attack; the Spalart-Allmaras model agreed better with experiment. Neglecting viscous cross-derivative terms caused poorer prediction in the wing tip vortex region. Output-based grid adaptation was applied to the unstructured-grid solutions. The adapted grids better resolved wake structures and reduced flap flow separation, which was also observed in uniform grid refinement studies. Limitations of the adaptation method as well as areas for future improvement were identified.

A FORTRAN code for the calculation of probe volume geometry changes in a laser anemometry system caused by window refraction

NASA Technical Reports Server (NTRS)

Owen, Albert K.

1987-01-01

A computer code was written which utilizes ray tracing techniques to predict the changes in position and geometry of a laser Doppler velocimeter probe volume resulting from refraction effects. The code predicts the position change, changes in beam crossing angle, and the amount of uncrossing that occur when the beams traverse a region with a changed index of refraction, such as a glass window. The code calculates the changes for flat plate, cylinder, general axisymmetric and general surface windows and is currently operational on a VAX 8600 computer system.

New Tool Released for Engine-Airframe Blade-Out Structural Simulations

NASA Technical Reports Server (NTRS)

Lawrence, Charles

2004-01-01

Researchers at the NASA Glenn Research Center have enhanced a general-purpose finite element code, NASTRAN, for engine-airframe structural simulations during steady-state and transient operating conditions. For steady-state simulations, the code can predict critical operating speeds, natural modes of vibration, and forced response (e.g., cabin noise and component fatigue). The code can be used to perform static analysis to predict engine-airframe response and component stresses due to maneuver loads. For transient response, the simulation code can be used to predict response due to bladeoff events and subsequent engine shutdown and windmilling conditions. In addition, the code can be used as a pretest analysis tool to predict the results of the bladeout test required for FAA certification of new and derivative aircraft engines. Before the present analysis code was developed, all the major aircraft engine and airframe manufacturers in the United States and overseas were performing similar types of analyses to ensure the structural integrity of engine-airframe systems. Although there were many similarities among the analysis procedures, each manufacturer was developing and maintaining its own structural analysis capabilities independently. This situation led to high software development and maintenance costs, complications with manufacturers exchanging models and results, and limitations in predicting the structural response to the desired degree of accuracy. An industry-NASA team was formed to overcome these problems by developing a common analysis tool that would satisfy all the structural analysis needs of the industry and that would be available and supported by a commercial software vendor so that the team members would be relieved of maintenance and development responsibilities. Input from all the team members was used to ensure that everyone's requirements were satisfied and that the best technology was incorporated into the code. Furthermore, because the code would be distributed by a commercial software vendor, it would be more readily available to engine and airframe manufacturers, as well as to nonaircraft companies that did not previously have access to this capability.

CFD Modeling of Free-Piston Stirling Engines

NASA Technical Reports Server (NTRS)

Ibrahim, Mounir B.; Zhang, Zhi-Guo; Tew, Roy C., Jr.; Gedeon, David; Simon, Terrence W.

2001-01-01

NASA Glenn Research Center (GRC) is funding Cleveland State University (CSU) to develop a reliable Computational Fluid Dynamics (CFD) code that can predict engine performance with the goal of significant improvements in accuracy when compared to one-dimensional (1-D) design code predictions. The funding also includes conducting code validation experiments at both the University of Minnesota (UMN) and CSU. In this paper a brief description of the work-in-progress is provided in the two areas (CFD and Experiments). Also, previous test results are compared with computational data obtained using (1) a 2-D CFD code obtained from Dr. Georg Scheuerer and further developed at CSU and (2) a multidimensional commercial code CFD-ACE+. The test data and computational results are for (1) a gas spring and (2) a single piston/cylinder with attached annular heat exchanger. The comparisons among the codes are discussed. The paper also discusses plans for conducting code validation experiments at CSU and UMN.

RACE, CODE OF THE STREET, AND VIOLENT DELINQUENCY: A MULTILEVEL INVESTIGATION OF NEIGHBORHOOD STREET CULTURE AND INDIVIDUAL NORMS OF VIOLENCE*

PubMed Central

Stewart, Eric A.; Simons, Ronald L.

2011-01-01

The study outlined in this article drew on Elijah Anderson’s (1999) code of the street perspective to examine the impact of neighborhood street culture on violent delinquency. Using data from more than 700 African American adolescents, we examined 1) whether neighborhood street culture predicts adolescent violence above and beyond an adolescent’s own street code values and 2) whether neighborhood street culture moderates individual-level street code values on adolescent violence. Consistent with Anderson’s hypotheses, neighborhood street culture significantly predicts violent delinquency independent of individual-level street code effects. Additionally, neighborhood street culture moderates individual-level street code values on violence in neighborhoods where the street culture is widespread. In particular, the effect of street code values on violence is enhanced in neighborhoods where the street culture is endorsed widely. PMID:21666759

Predicted and experimental aerodynamic forces on the Darrieus rotor

NASA Astrophysics Data System (ADS)

Paraschivoiu, I.

1983-12-01

The present paper compares the aerodynamic loads predicted by a double-multiple-streamtube model with wind tunnel measurements for a straight-bladed Darrieus rotor. Thus the CARDAA computer code uses two constant-interference factors in the induced velocity for estimating the aerodynamic loads. This code has been improved by considering the variation in the upwind and downwind induced velocities as a function of the blade position, and, in this case, the CARDAAV code is used. The Boeing-Vertol dynamic-stall model is incorporated in both the CARDAA and CARDAAV codes, and a better approach is obtained. The transient normal- and tangential-force coefficients predicted with and without dynamic-stall effects are compared with wind tunnel data for one and two NACA 0018 straight-bladed rotors. The results are given for a rotor with a large solidity (chord-to-radius ratio of 0.20) at two tip-speed ratios (X = 1.5 and 3.0) and at a low Reynolds number of 3.8 x 10 to the 4th. The comparisons between experimental data and theoretical results show the CARDAAV predictions to be more accurate than those estimated by the CARDAA code.

Prediction of effects of wing contour modifications on low-speed maximum lift and transonic performance for the EA-6B aircraft

NASA Technical Reports Server (NTRS)

Allison, Dennis O.; Waggoner, E. G.

1990-01-01

Computational predictions of the effects of wing contour modifications on maximum lift and transonic performance were made and verified against low speed and transonic wind tunnel data. This effort was part of a program to improve the maneuvering capability of the EA-6B electronics countermeasures aircraft, which evolved from the A-6 attack aircraft. The predictions were based on results from three computer codes which all include viscous effects: MCARF, a 2-D subsonic panel code; TAWFIVE, a transonic full potential code; and WBPPW, a transonic small disturbance potential flow code. The modifications were previously designed with the aid of these and other codes. The wing modifications consists of contour changes to the leading edge slats and trailing edge flaps and were designed for increased maximum lift with minimum effect on transonic performance. The prediction of the effects of the modifications are presented, with emphasis on verification through comparisons with wind tunnel data from the National Transonic Facility. Attention is focused on increments in low speed maximum lift and increments in transonic lift, pitching moment, and drag resulting from the contour modifications.

An integrative approach to predicting the functional effects of small indels in non-coding regions of the human genome

PubMed Central

Ferlaino, Michael; Rogers, Mark F.; Shihab, Hashem A.; Mort, Matthew; Cooper, David N.; Gaunt, Tom R.; Campbell, Colin

2018-01-01

Background Small insertions and deletions (indels) have a significant influence in human disease and, in terms of frequency, they are second only to single nucleotide variants as pathogenic mutations. As the majority of mutations associated with complex traits are located outside the exome, it is crucial to investigate the potential pathogenic impact of indels in non-coding regions of the human genome. Results We present FATHMM-indel, an integrative approach to predict the functional effect, pathogenic or neutral, of indels in non-coding regions of the human genome. Our method exploits various genomic annotations in addition to sequence data. When validated on benchmark data, FATHMM-indel significantly outperforms CADD and GAVIN, state of the art models in assessing the pathogenic impact of non-coding variants. FATHMM-indel is available via a web server at indels.biocompute.org.uk. Conclusions FATHMM-indel can accurately predict the functional impact and prioritise small indels throughout the whole non-coding genome. PMID:28985712

Dynamic Divisive Normalization Predicts Time-Varying Value Coding in Decision-Related Circuits

PubMed Central

LoFaro, Thomas; Webb, Ryan; Glimcher, Paul W.

2014-01-01

Normalization is a widespread neural computation, mediating divisive gain control in sensory processing and implementing a context-dependent value code in decision-related frontal and parietal cortices. Although decision-making is a dynamic process with complex temporal characteristics, most models of normalization are time-independent and little is known about the dynamic interaction of normalization and choice. Here, we show that a simple differential equation model of normalization explains the characteristic phasic-sustained pattern of cortical decision activity and predicts specific normalization dynamics: value coding during initial transients, time-varying value modulation, and delayed onset of contextual information. Empirically, we observe these predicted dynamics in saccade-related neurons in monkey lateral intraparietal cortex. Furthermore, such models naturally incorporate a time-weighted average of past activity, implementing an intrinsic reference-dependence in value coding. These results suggest that a single network mechanism can explain both transient and sustained decision activity, emphasizing the importance of a dynamic view of normalization in neural coding. PMID:25429145

An integrative approach to predicting the functional effects of small indels in non-coding regions of the human genome.

PubMed

Ferlaino, Michael; Rogers, Mark F; Shihab, Hashem A; Mort, Matthew; Cooper, David N; Gaunt, Tom R; Campbell, Colin

2017-10-06

Small insertions and deletions (indels) have a significant influence in human disease and, in terms of frequency, they are second only to single nucleotide variants as pathogenic mutations. As the majority of mutations associated with complex traits are located outside the exome, it is crucial to investigate the potential pathogenic impact of indels in non-coding regions of the human genome. We present FATHMM-indel, an integrative approach to predict the functional effect, pathogenic or neutral, of indels in non-coding regions of the human genome. Our method exploits various genomic annotations in addition to sequence data. When validated on benchmark data, FATHMM-indel significantly outperforms CADD and GAVIN, state of the art models in assessing the pathogenic impact of non-coding variants. FATHMM-indel is available via a web server at indels.biocompute.org.uk. FATHMM-indel can accurately predict the functional impact and prioritise small indels throughout the whole non-coding genome.

Data Assimilation - Advances and Applications

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

Williams, Brian J.

2014-07-30

This presentation provides an overview of data assimilation (model calibration) for complex computer experiments. Calibration refers to the process of probabilistically constraining uncertain physics/engineering model inputs to be consistent with observed experimental data. An initial probability distribution for these parameters is updated using the experimental information. Utilization of surrogate models and empirical adjustment for model form error in code calibration form the basis for the statistical methodology considered. The role of probabilistic code calibration in supporting code validation is discussed. Incorporation of model form uncertainty in rigorous uncertainty quantification (UQ) analyses is also addressed. Design criteria used within a batchmore » sequential design algorithm are introduced for efficiently achieving predictive maturity and improved code calibration. Predictive maturity refers to obtaining stable predictive inference with calibrated computer codes. These approaches allow for augmentation of initial experiment designs for collecting new physical data. A standard framework for data assimilation is presented and techniques for updating the posterior distribution of the state variables based on particle filtering and the ensemble Kalman filter are introduced.« less

Probabilistic Analysis of Aircraft Gas Turbine Disk Life and Reliability

NASA Technical Reports Server (NTRS)

Melis, Matthew E.; Zaretsky, Erwin V.; August, Richard

1999-01-01

Two series of low cycle fatigue (LCF) test data for two groups of different aircraft gas turbine engine compressor disk geometries were reanalyzed and compared using Weibull statistics. Both groups of disks were manufactured from titanium (Ti-6Al-4V) alloy. A NASA Glenn Research Center developed probabilistic computer code Probable Cause was used to predict disk life and reliability. A material-life factor A was determined for titanium (Ti-6Al-4V) alloy based upon fatigue disk data and successfully applied to predict the life of the disks as a function of speed. A comparison was made with the currently used life prediction method based upon crack growth rate. Applying an endurance limit to the computer code did not significantly affect the predicted lives under engine operating conditions. Failure location prediction correlates with those experimentally observed in the LCF tests. A reasonable correlation was obtained between the predicted disk lives using the Probable Cause code and a modified crack growth method for life prediction. Both methods slightly overpredict life for one disk group and significantly under predict it for the other.

Development of a cryogenic mixed fluid J-T cooling computer code, 'JTMIX'

NASA Technical Reports Server (NTRS)

Jones, Jack A.

1991-01-01

An initial study was performed for analyzing and predicting the temperatures and cooling capacities when mixtures of fluids are used in Joule-Thomson coolers and in heat pipes. A computer code, JTMIX, was developed for mixed gas J-T analysis for any fluid combination of neon, nitrogen, various hydrocarbons, argon, oxygen, carbon monoxide, carbon dioxide, and hydrogen sulfide. When used in conjunction with the NIST computer code, DDMIX, it has accurately predicted order-of-magnitude increases in J-T cooling capacities when various hydrocarbons are added to nitrogen, and it predicts nitrogen normal boiling point depressions to as low as 60 K when neon is added.

Evaluation of COBRA III-C and SABRE-I (wire wrap version) computational results by comparison with steady-state data from a 19-pin internally guard heated sodium cooled bundle with a six-channel central blockage (THORS bundle 3C). [LMFBR

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

Dearing, J F; Rose, S D; Nelson, W R

The predicted computational results of two well-known sub-channel analysis codes, COBRA-III-C and SABRE-I (wire wrap version), have been evaluated by comparison with steady state temperature data from the THORS Facility at ORNL. Both codes give good predictions of transverse and axial temperatures when compared with wire wrap thermocouple data. The crossflow velocity profiles predicted by these codes are similar which is encouraging since the wire wrap models are based on different assumptions.

More About Vector Adaptive/Predictive Coding Of Speech

NASA Technical Reports Server (NTRS)

Jedrey, Thomas C.; Gersho, Allen

1992-01-01

Report presents additional information about digital speech-encoding and -decoding system described in "Vector Adaptive/Predictive Encoding of Speech" (NPO-17230). Summarizes development of vector adaptive/predictive coding (VAPC) system and describes basic functions of algorithm. Describes refinements introduced enabling receiver to cope with errors. VAPC algorithm implemented in integrated-circuit coding/decoding processors (codecs). VAPC and other codecs tested under variety of operating conditions. Tests designed to reveal effects of various background quiet and noisy environments and of poor telephone equipment. VAPC found competitive with and, in some respects, superior to other 4.8-kb/s codecs and other codecs of similar complexity.

Role of Meteorology in Flights of a Solar-Powered Airplane

NASA Technical Reports Server (NTRS)

Donohue, Casey

2004-01-01

In the summer of 2001, the Helios prototype solar-powered uninhabited aerial vehicle (UAV) [a lightweight, remotely piloted airplane] was deployed to the Pacific Missile Range Facility (PMRF), at Kauai, Hawaii, in an attempt to fly to altitudes above 100,000 ft (30.48 km). The goal of flying a UAV to such high altitudes has been designated a level-I milestone of the NASA Environmental Research Aircraft and Sensor Technology (ERAST) program. In support of this goal, meteorologists from NASA Dryden Flight Research Center were sent to PMRF, as part of the flight crew, to provide current and forecast weather information to the pilots, mission directors, and planners. Information of this kind is needed to optimize flight conditions for peak aircraft performance and to enable avoidance of weather conditions that could adversely affect safety. In general, the primary weather data of concern for ground and flight operations are wind speeds (see Figure 1). Because of its long wing span [247 ft (.75 m)] and low weight [1,500 to 1,600 lb (about 680 to 726 kg)], the Helios airplane is sensitive to wind speeds exceeding 7 kn (3.6 m/s) at the surface. Also, clouds are of concern because they can block sunlight needed to energize an array of solar photovoltaic cells that provide power to the airplane. Vertical wind shear is very closely monitored in order to prevent damage or loss of control due to turbulence.

Latitudinal variation of speed and mass flux in the acceleration region of the solar wind inferred from spectral broadening measurements

NASA Technical Reports Server (NTRS)

Woo, Richard; Goldstein, Richard M.

1994-01-01

Spectral broadening measurements conducted at S-band (13-cm wavelength) during solar minimum conditions in the heliocentric distance range of 3-8 R(sub O) by Mariner 4, Pioneer 10, Mariner 10, Helios 1, Helios 2, and Viking have been combined to reveal a factor of 2.6 reduction in bandwidth from equator to pole. Since spectral broadening bandwidth depends on electron density fluctuation and solar wind speed, and latitudinal variation of the former is available from coherence bandwidth measurements, the remote sensing spectral broadening measurements provide the first determination of the latitudinal variation of solar wind speed in the acceleration region. When combined with electron density measurements deduced from white-light coronagraphs, this result also leads to the first determination of the latitudinal variation of mass flux in the acceleration region. From equator to pole, solar wind speed increases by a factor of 2.2, while mass flux decreases by a factor of 2.3. These results are consistent with measurements of solar wind speed by multi-station intensity scintillation measurements, as well as measurements of mass flux inferred from Lyman alpha observations, both of which pertain to the solar wind beyond 0.5 AU. The spectral broadening observations, therefore, strengthen earlier conclusions about the latitudinal variation of solar wind speed and mass flux, and reinforce current solar coronal models and their implications for solar wind acceleration and solar wind modeling.

Promoting access to and use of seismic data in a large scientific community. SpaceInn data handling and archiving

NASA Astrophysics Data System (ADS)

Michel, Eric; Belkacem, Kevin; Samadi, Reza; Assis Peralta, Raphael de; Renié, Christian; Abed, Mahfoudh; Lin, Guangyuan; Christensen-Dalsgaard, Jørgen; Houdek, Günter; Handberg, Rasmus; Gizon, Laurent; Burston, Raymond; Nagashima, Kaori; Pallé, Pere; Poretti, Ennio; Rainer, Monica; Mistò, Angelo; Panzera, Maria Rosa; Roth, Markus

2017-10-01

The growing amount of seismic data available from space missions (SOHO, CoRoT, Kepler, SDO,…) but also from ground-based facilities (GONG, BiSON, ground-based large programmes…), stellar modelling and numerical simulations, creates new scientific perspectives such as characterizing stellar populations in our Galaxy or planetary systems by providing model-independent global properties of stars such as mass, radius, and surface gravity within several percent accuracy, as well as constraints on the age. These applications address a broad scientific community beyond the solar and stellar one and require combining indices elaborated with data from different databases (e.g. seismic archives and ground-based spectroscopic surveys). It is thus a basic requirement to develop a simple and effcient access to these various data resources and dedicated tools. In the framework of the European project SpaceInn (FP7), several data sources have been developed or upgraded. The Seismic Plus Portal has been developed, where synthetic descriptions of the most relevant existing data sources can be found, as well as tools allowing to localize existing data for given objects or period and helping the data query. This project has been developed within the Virtual Observatory (VO) framework. In this paper, we give a review of the various facilities and tools developed within this programme. The SpaceInn project (Exploitation of Space Data for Innovative Helio- and Asteroseismology) has been initiated by the European Helio- and Asteroseismology Network (HELAS).

Number density structures in the inner heliosphere

NASA Astrophysics Data System (ADS)

Stansby, D.; Horbury, T. S.

2018-06-01

Aims: The origins and generation mechanisms of the slow solar wind are still unclear. Part of the slow solar wind is populated by number density structures, discrete patches of increased number density that are frozen in to and move with the bulk solar wind. In this paper we aimed to provide the first in-situ statistical study of number density structures in the inner heliosphere. Methods: We reprocessed in-situ ion distribution functions measured by Helios in the inner heliosphere to provide a new reliable set of proton plasma moments for the entire mission. From this new data set we looked for number density structures measured within 0.5 AU of the Sun and studied their properties. Results: We identified 140 discrete areas of enhanced number density. The structures occurred exclusively in the slow solar wind and spanned a wide range of length scales from 50 Mm to 2000 Mm, which includes smaller scales than have been previously observed. They were also consistently denser and hotter that the surrounding plasma, but had lower magnetic field strengths, and therefore remained in pressure balance. Conclusions: Our observations show that these structures are present in the slow solar wind at a wide range of scales, some of which are too small to be detected by remote sensing instruments. These structures are rare, accounting for only 1% of the slow solar wind measured by Helios, and are not a significant contribution to the mass flux of the solar wind.

Evaluation of the constant pressure panel method (CPM) for unsteady air loads prediction

NASA Technical Reports Server (NTRS)

Appa, Kari; Smith, Michael J. C.

1988-01-01

This paper evaluates the capability of the constant pressure panel method (CPM) code to predict unsteady aerodynamic pressures, lift and moment distributions, and generalized forces for general wing-body configurations in supersonic flow. Stability derivatives are computed and correlated for the X-29 and an Oblique Wing Research Aircraft, and a flutter analysis is carried out for a wing wind tunnel test example. Most results are shown to correlate well with test or published data. Although the emphasis of this paper is on evaluation, an improvement in the CPM code's handling of intersecting lifting surfaces is briefly discussed. An attractive feature of the CPM code is that it shares the basic data requirements and computational arrangements of the doublet lattice method. A unified code to predict unsteady subsonic or supersonic airloads is therefore possible.

Enhancement of the CAVE computer code

NASA Astrophysics Data System (ADS)

Rathjen, K. A.; Burk, H. O.

1983-12-01

The computer code CAVE (Conduction Analysis via Eigenvalues) is a convenient and efficient computer code for predicting two dimensional temperature histories within thermal protection systems for hypersonic vehicles. The capabilities of CAVE were enhanced by incorporation of the following features into the code: real gas effects in the aerodynamic heating predictions, geometry and aerodynamic heating package for analyses of cone shaped bodies, input option to change from laminar to turbulent heating predictions on leading edges, modification to account for reduction in adiabatic wall temperature with increase in leading sweep, geometry package for two dimensional scramjet engine sidewall, with an option for heat transfer to external and internal surfaces, print out modification to provide tables of select temperatures for plotting and storage, and modifications to the radiation calculation procedure to eliminate temperature oscillations induced by high heating rates. These new features are described.

Mass transfer effects in a gasification riser

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

Breault, Ronald W.; Li, Tingwen; Nicoletti, Phillip

2013-07-01

In the development of multiphase reacting computational fluid dynamics (CFD) codes, a number of simplifications were incorporated into the codes and models. One of these simplifications was the use of a simplistic mass transfer correlation for the faster reactions and omission of mass transfer effects completely on the moderate speed and slow speed reactions such as those in a fluidized bed gasifier. Another problem that has propagated is that the mass transfer correlation used in the codes is not universal and is being used far from its developed bubbling fluidized bed regime when applied to circulating fluidized bed (CFB) risermore » reactors. These problems are true for the major CFD codes. To alleviate this problem, a mechanistic based mass transfer coefficient algorithm has been developed based upon an earlier work by Breault et al. This fundamental approach uses the local hydrodynamics to predict a local, time varying mass transfer coefficient. The predicted mass transfer coefficients and the corresponding Sherwood numbers agree well with literature data and are typically about an order of magnitude lower than the correlation noted above. The incorporation of the new mass transfer model gives the expected behavior for all the gasification reactions evaluated in the paper. At the expected and typical design values for the solid flow rate in a CFB riser gasifier an ANOVA analysis has shown the predictions from the new code to be significantly different from the original code predictions. The new algorithm should be used such that the conversions are not over predicted. Additionally, its behaviors with changes in solid flow rate are consistent with the changes in the hydrodynamics.« less

Automating annotation of information-giving for analysis of clinical conversation.

PubMed

Mayfield, Elijah; Laws, M Barton; Wilson, Ira B; Penstein Rosé, Carolyn

2014-02-01

Coding of clinical communication for fine-grained features such as speech acts has produced a substantial literature. However, annotation by humans is laborious and expensive, limiting application of these methods. We aimed to show that through machine learning, computers could code certain categories of speech acts with sufficient reliability to make useful distinctions among clinical encounters. The data were transcripts of 415 routine outpatient visits of HIV patients which had previously been coded for speech acts using the Generalized Medical Interaction Analysis System (GMIAS); 50 had also been coded for larger scale features using the Comprehensive Analysis of the Structure of Encounters System (CASES). We aggregated selected speech acts into information-giving and requesting, then trained the machine to automatically annotate using logistic regression classification. We evaluated reliability by per-speech act accuracy. We used multiple regression to predict patient reports of communication quality from post-visit surveys using the patient and provider information-giving to information-requesting ratio (briefly, information-giving ratio) and patient gender. Automated coding produces moderate reliability with human coding (accuracy 71.2%, κ=0.57), with high correlation between machine and human prediction of the information-giving ratio (r=0.96). The regression significantly predicted four of five patient-reported measures of communication quality (r=0.263-0.344). The information-giving ratio is a useful and intuitive measure for predicting patient perception of provider-patient communication quality. These predictions can be made with automated annotation, which is a practical option for studying large collections of clinical encounters with objectivity, consistency, and low cost, providing greater opportunity for training and reflection for care providers.

A thermal NO(x) prediction model - Scalar computation module for CFD codes with fluid and kinetic effects

NASA Technical Reports Server (NTRS)

Mcbeath, Giorgio; Ghorashi, Bahman; Chun, Kue

1993-01-01

A thermal NO(x) prediction model is developed to interface with a CFD, k-epsilon based code. A converged solution from the CFD code is the input to the postprocessing model for prediction of thermal NO(x). The model uses a decoupled analysis to estimate the equilibrium level of (NO(x))e which is the constant rate limit. This value is used to estimate the flame (NO(x)) and in turn predict the rate of formation at each node using a two-step Zeldovich mechanism. The rate is fixed on the NO(x) production rate plot by estimating the time to reach equilibrium by a differential analysis based on the reaction: O + N2 = NO + N. The rate is integrated in the nonequilibrium time space based on the residence time at each node in the computational domain. The sum of all nodal predictions yields the total NO(x) level.

Experimental evaluation of a flat wake theory for predicting rotor inflow-wake velocities

NASA Technical Reports Server (NTRS)

Wilson, John C.

1992-01-01

The theory for predicting helicopter inflow-wake velocities called flat wake theory was correlated with several sets of experimental data. The theory was developed by V. E. Baskin of the USSR, and a computer code known as DOWN was developed at Princeton University to implement the theory. The theory treats the wake geometry as rigid without interaction between induced velocities and wake structure. The wake structure is assumed to be a flat sheet of vorticity composed of trailing elements whose strength depends on the azimuthal and radial distributions of circulation on a rotor blade. The code predicts the three orthogonal components of flow velocity in the field surrounding the rotor. The predictions can be utilized in rotor performance and helicopter real-time flight-path simulation. The predictive capability of the coded version of flat wake theory provides vertical inflow patterns similar to experimental patterns.

RBind: computational network method to predict RNA binding sites.

PubMed

Wang, Kaili; Jian, Yiren; Wang, Huiwen; Zeng, Chen; Zhao, Yunjie

2018-04-26

Non-coding RNA molecules play essential roles by interacting with other molecules to perform various biological functions. However, it is difficult to determine RNA structures due to their flexibility. At present, the number of experimentally solved RNA-ligand and RNA-protein structures is still insufficient. Therefore, binding sites prediction of non-coding RNA is required to understand their functions. Current RNA binding site prediction algorithms produce many false positive nucleotides that are distance away from the binding sites. Here, we present a network approach, RBind, to predict the RNA binding sites. We benchmarked RBind in RNA-ligand and RNA-protein datasets. The average accuracy of 0.82 in RNA-ligand and 0.63 in RNA-protein testing showed that this network strategy has a reliable accuracy for binding sites prediction. The codes and datasets are available at https://zhaolab.com.cn/RBind. yjzhaowh@mail.ccnu.edu.cn. Supplementary data are available at Bioinformatics online.

FILM-30: A Heat Transfer Properties Code for Water Coolant

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

MARSHALL, THERON D.

2001-02-01

A FORTRAN computer code has been written to calculate the heat transfer properties at the wetted perimeter of a coolant channel when provided the bulk water conditions. This computer code is titled FILM-30 and the code calculates its heat transfer properties by using the following correlations: (1) Sieder-Tate: forced convection, (2) Bergles-Rohsenow: onset to nucleate boiling, (3) Bergles-Rohsenow: partially developed nucleate boiling, (4) Araki: fully developed nucleate boiling, (5) Tong-75: critical heat flux (CHF), and (6) Marshall-98: transition boiling. FILM-30 produces output files that provide the heat flux and heat transfer coefficient at the wetted perimeter as a function ofmore » temperature. To validate FILM-30, the calculated heat transfer properties were used in finite element analyses to predict internal temperatures for a water-cooled copper mockup under one-sided heating from a rastered electron beam. These predicted temperatures were compared with the measured temperatures from the author's 1994 and 1998 heat transfer experiments. There was excellent agreement between the predicted and experimentally measured temperatures, which confirmed the accuracy of FILM-30 within the experimental range of the tests. FILM-30 can accurately predict the CHF and transition boiling regimes, which is an important advantage over current heat transfer codes. Consequently, FILM-30 is ideal for predicting heat transfer properties for applications that feature high heat fluxes produced by one-sided heating.« less

PLncPRO for prediction of long non-coding RNAs (lncRNAs) in plants and its application for discovery of abiotic stress-responsive lncRNAs in rice and chickpea

PubMed Central

Singh, Urminder; Rajkumar, Mohan Singh; Garg, Rohini

2017-01-01

Abstract Long non-coding RNAs (lncRNAs) make up a significant portion of non-coding RNAs and are involved in a variety of biological processes. Accurate identification/annotation of lncRNAs is the primary step for gaining deeper insights into their functions. In this study, we report a novel tool, PLncPRO, for prediction of lncRNAs in plants using transcriptome data. PLncPRO is based on machine learning and uses random forest algorithm to classify coding and long non-coding transcripts. PLncPRO has better prediction accuracy as compared to other existing tools and is particularly well-suited for plants. We developed consensus models for dicots and monocots to facilitate prediction of lncRNAs in non-model/orphan plants. The performance of PLncPRO was quite better with vertebrate transcriptome data as well. Using PLncPRO, we discovered 3714 and 3457 high-confidence lncRNAs in rice and chickpea, respectively, under drought or salinity stress conditions. We investigated different characteristics and differential expression under drought/salinity stress conditions, and validated lncRNAs via RT-qPCR. Overall, we developed a new tool for the prediction of lncRNAs in plants and showed its utility via identification of lncRNAs in rice and chickpea. PMID:29036354

Validity of Principal Diagnoses in Discharge Summaries and ICD-10 Coding Assessments Based on National Health Data of Thailand.

PubMed

Sukanya, Chongthawonsatid

2017-10-01

This study examined the validity of the principal diagnoses on discharge summaries and coding assessments. Data were collected from the National Health Security Office (NHSO) of Thailand in 2015. In total, 118,971 medical records were audited. The sample was drawn from government hospitals and private hospitals covered by the Universal Coverage Scheme in Thailand. Hospitals and cases were selected using NHSO criteria. The validity of the principal diagnoses listed in the "Summary and Coding Assessment" forms was established by comparing data from the discharge summaries with data obtained from medical record reviews, and additionally, by comparing data from the coding assessments with data in the computerized ICD (the data base used for reimbursement-purposes). The summary assessments had low sensitivities (7.3%-37.9%), high specificities (97.2%-99.8%), low positive predictive values (9.2%-60.7%), and high negative predictive values (95.9%-99.3%). The coding assessments had low sensitivities (31.1%-69.4%), high specificities (99.0%-99.9%), moderate positive predictive values (43.8%-89.0%), and high negative predictive values (97.3%-99.5%). The discharge summaries and codings often contained mistakes, particularly the categories "Endocrine, nutritional, and metabolic diseases", "Symptoms, signs, and abnormal clinical and laboratory findings not elsewhere classified", "Factors influencing health status and contact with health services", and "Injury, poisoning, and certain other consequences of external causes". The validity of the principal diagnoses on the summary and coding assessment forms was found to be low. The training of physicians and coders must be strengthened to improve the validity of discharge summaries and codings.

Euler flow predictions for an oscillating cascade using a high resolution wave-split scheme

NASA Technical Reports Server (NTRS)

Huff, Dennis L.; Swafford, Timothy W.; Reddy, T. S. R.

1991-01-01

A compressible flow code that can predict the nonlinear unsteady aerodynamics associated with transonic flows over oscillating cascades is developed and validated. The code solves the two dimensional, unsteady Euler equations using a time-marching, flux-difference splitting scheme. The unsteady pressures and forces can be determined for arbitrary input motions, although only harmonic pitching and plunging motions are addressed. The code solves the flow equations on a H-grid which is allowed to deform with the airfoil motion. Predictions are presented for both flat plate cascades and loaded airfoil cascades. Results are compared to flat plate theory and experimental data. Predictions are also presented for several oscillating cascades with strong normal shocks where the pitching amplitudes, cascade geometry and interblade phase angles are varied to investigate nonlinear behavior.

Aeroacoustic Codes for Rotor Harmonic and BVI Noise. CAMRAD.Mod1/HIRES: Methodology and Users' Manual

NASA Technical Reports Server (NTRS)

Boyd, D. Douglas, Jr.; Brooks, Thomas F.; Burley, Casey L.; Jolly, J. Ralph, Jr.

1998-01-01

This document details the methodology and use of the CAMRAD.Mod1/HIRES codes, which were developed at NASA Langley Research Center for the prediction of helicopter harmonic and Blade-Vortex Interaction (BVI) noise. CANMAD.Mod1 is a substantially modified version of the performance/trim/wake code CANMAD. High resolution blade loading is determined in post-processing by HIRES and an associated indicial aerodynamics code. Extensive capabilities of importance to noise prediction accuracy are documented, including a new multi-core tip vortex roll-up wake model, higher harmonic and individual blade control, tunnel and fuselage correction input, diagnostic blade motion input, and interfaces for acoustic and CFD aerodynamics codes. Modifications and new code capabilities are documented with examples. A users' job preparation guide and listings of variables and namelists are given.

Modification and Validation of Conceptual Design Aerodynamic Prediction Method HASC95 With VTXCHN

NASA Technical Reports Server (NTRS)

Albright, Alan E.; Dixon, Charles J.; Hegedus, Martin C.

1996-01-01

A conceptual/preliminary design level subsonic aerodynamic prediction code HASC (High Angle of Attack Stability and Control) has been improved in several areas, validated, and documented. The improved code includes improved methodologies for increased accuracy and robustness, and simplified input/output files. An engineering method called VTXCHN (Vortex Chine) for prediciting nose vortex shedding from circular and non-circular forebodies with sharp chine edges has been improved and integrated into the HASC code. This report contains a summary of modifications, description of the code, user's guide, and validation of HASC. Appendices include discussion of a new HASC utility code, listings of sample input and output files, and a discussion of the application of HASC to buffet analysis.

An emulator for minimizing computer resources for finite element analysis

NASA Technical Reports Server (NTRS)

Melosh, R.; Utku, S.; Islam, M.; Salama, M.

1984-01-01

A computer code, SCOPE, has been developed for predicting the computer resources required for a given analysis code, computer hardware, and structural problem. The cost of running the code is a small fraction (about 3 percent) of the cost of performing the actual analysis. However, its accuracy in predicting the CPU and I/O resources depends intrinsically on the accuracy of calibration data that must be developed once for the computer hardware and the finite element analysis code of interest. Testing of the SCOPE code on the AMDAHL 470 V/8 computer and the ELAS finite element analysis program indicated small I/O errors (3.2 percent), larger CPU errors (17.8 percent), and negligible total errors (1.5 percent).

The problem with brain GUTs: conflation of different senses of "prediction" threatens metaphysical disaster.

PubMed

Anderson, Michael L; Chemero, Tony

2013-06-01

Clark appears to be moving toward epistemic internalism, which he once rightly rejected. This results from a double over-interpretation of predictive coding's significance. First, Clark argues that predictive coding offers a Grand Unified Theory (GUT) of brain function. Second, he over-reads its epistemic import, perhaps even conflating causal and epistemic mediators. We argue instead for a plurality of neurofunctional principles.

The Influence of Viscous Effects on Ice Accretion Prediction and Airfoil Performance Predictions

NASA Technical Reports Server (NTRS)

Kreeger, Richard E.; Wright, William B.

2005-01-01

A computational study was conducted to evaluate the effectiveness of using a viscous flow solution in an ice accretion code and the resulting accuracy of aerodynamic performance prediction. Ice shapes were obtained for one single-element and one multi-element airfoil using both potential flow and Navier-Stokes flowfields in the LEWICE ice accretion code. Aerodynamics were then calculated using a Navier-Stokes flow solver.

Anisotropic connectivity implements motion-based prediction in a spiking neural network.

PubMed

Kaplan, Bernhard A; Lansner, Anders; Masson, Guillaume S; Perrinet, Laurent U

2013-01-01

Predictive coding hypothesizes that the brain explicitly infers upcoming sensory input to establish a coherent representation of the world. Although it is becoming generally accepted, it is not clear on which level spiking neural networks may implement predictive coding and what function their connectivity may have. We present a network model of conductance-based integrate-and-fire neurons inspired by the architecture of retinotopic cortical areas that assumes predictive coding is implemented through network connectivity, namely in the connection delays and in selectiveness for the tuning properties of source and target cells. We show that the applied connection pattern leads to motion-based prediction in an experiment tracking a moving dot. In contrast to our proposed model, a network with random or isotropic connectivity fails to predict the path when the moving dot disappears. Furthermore, we show that a simple linear decoding approach is sufficient to transform neuronal spiking activity into a probabilistic estimate for reading out the target trajectory.

PopCORN: Hunting down the differences between binary population synthesis codes

NASA Astrophysics Data System (ADS)

Toonen, S.; Claeys, J. S. W.; Mennekens, N.; Ruiter, A. J.

2014-02-01

Context. Binary population synthesis (BPS) modelling is a very effective tool to study the evolution and properties of various types of close binary systems. The uncertainty in the parameters of the model and their effect on a population can be tested in a statistical way, which then leads to a deeper understanding of the underlying (sometimes poorly understood) physical processes involved. Several BPS codes exist that have been developed with different philosophies and aims. Although BPS has been very successful for studies of many populations of binary stars, in the particular case of the study of the progenitors of supernovae Type Ia, the predicted rates and ZAMS progenitors vary substantially between different BPS codes. Aims: To understand the predictive power of BPS codes, we study the similarities and differences in the predictions of four different BPS codes for low- and intermediate-mass binaries. We investigate the differences in the characteristics of the predicted populations, and whether they are caused by different assumptions made in the BPS codes or by numerical effects, e.g. a lack of accuracy in BPS codes. Methods: We compare a large number of evolutionary sequences for binary stars, starting with the same initial conditions following the evolution until the first (and when applicable, the second) white dwarf (WD) is formed. To simplify the complex problem of comparing BPS codes that are based on many (often different) assumptions, we equalise the assumptions as much as possible to examine the inherent differences of the four BPS codes. Results: We find that the simulated populations are similar between the codes. Regarding the population of binaries with one WD, there is very good agreement between the physical characteristics, the evolutionary channels that lead to the birth of these systems, and their birthrates. Regarding the double WD population, there is a good agreement on which evolutionary channels exist to create double WDs and a rough agreement on the characteristics of the double WD population. Regarding which progenitor systems lead to a single and double WD system and which systems do not, the four codes agree well. Most importantly, we find that for these two populations, the differences in the predictions from the four codes are not due to numerical differences, but because of different inherent assumptions. We identify critical assumptions for BPS studies that need to be studied in more detail. Appendices are available in electronic form at http://www.aanda.org

NASA Solar Array Demonstrates Commercial Potential

NASA Technical Reports Server (NTRS)

Creech, Gray

2006-01-01

A state-of-the-art solar-panel array demonstration site at NASA's Dryden Flight Research Center provides a unique opportunity for studying the latest in high-efficiency solar photovoltaic cells. This five-kilowatt solar-array site (see Figure 1) is a technology-transfer and commercialization success for NASA. Among the solar cells at this site are cells of a type that was developed in Dryden Flight Research Center s Environmental Research Aircraft and Sensor Technology (ERAST) program for use in NASA s Helios solar-powered airplane. This cell type, now denoted as A-300, has since been transferred to SunPower Corporation of Sunnyvale, California, enabling mass production of the cells for the commercial market. High efficiency separates these advanced cells from typical previously commercially available solar cells: Whereas typical previously commercially available cells are 12 to 15 percent efficient at converting sunlight to electricity, these advanced cells exhibit efficiencies approaching 23 percent. The increase in efficiency is due largely to the routing of electrical connections behind the cells (see Figure 2). This approach to increasing efficiency originated as a solution to the problem of maximizing the degree of utilization of the limited space available atop the wing of the Helios airplane. In retrospect, the solar cells in use at this site could be used on Helios, but the best cells otherwise commercially available could not be so used, because of their lower efficiencies. Historically, solar cells have been fabricated by use of methods that are common in the semiconductor industry. One of these methods includes the use of photolithography to define the rear electrical-contact features - diffusions, contact openings, and fingers. SunPower uses these methods to produce the advanced cells. To reduce fabrication costs, SunPower continues to explore new methods to define the rear electrical-contact features. The equipment at the demonstration site includes two fixed-angle solar arrays and one single-axis Sun-tracking array. One of the fixed arrays contains typical less-efficient commercial solar cells and is being used as a baseline for comparison of the other fixed array, which contains the advanced cells. The Sun-tracking array tilts to follow the Sun, using an advanced, real-time tracking device rather than customary pre-programmed mechanisms. Part of the purpose served by the demonstration is to enable determination of any potential advantage of a tracking array over a fixed array. The arrays are monitored remotely on a computer that displays pertinent information regarding the functioning of the arrays.

Coastal Processes: Challenges for Monitoring and Prediction

DTIC Science & Technology

2009-01-01

Code 1008.3 ADOR/Director NCST E. R. Franchi , 7000 Public Affairs (Unclassified/ Unlimited Only). Code 703o 4 Division, Code Author, Code n...Research Global and the Fondazione Cassa di Risparmio di La Spezia for the financial support provided for the conference and the special issue.

Predictive Coding: A Possible Explanation of Filling-In at the Blind Spot

PubMed Central

Raman, Rajani; Sarkar, Sandip

2016-01-01

Filling-in at the blind spot is a perceptual phenomenon in which the visual system fills the informational void, which arises due to the absence of retinal input corresponding to the optic disc, with surrounding visual attributes. It is known that during filling-in, nonlinear neural responses are observed in the early visual area that correlates with the perception, but the knowledge of underlying neural mechanism for filling-in at the blind spot is far from complete. In this work, we attempted to present a fresh perspective on the computational mechanism of filling-in process in the framework of hierarchical predictive coding, which provides a functional explanation for a range of neural responses in the cortex. We simulated a three-level hierarchical network and observe its response while stimulating the network with different bar stimulus across the blind spot. We find that the predictive-estimator neurons that represent blind spot in primary visual cortex exhibit elevated non-linear response when the bar stimulated both sides of the blind spot. Using generative model, we also show that these responses represent the filling-in completion. All these results are consistent with the finding of psychophysical and physiological studies. In this study, we also demonstrate that the tolerance in filling-in qualitatively matches with the experimental findings related to non-aligned bars. We discuss this phenomenon in the predictive coding paradigm and show that all our results could be explained by taking into account the efficient coding of natural images along with feedback and feed-forward connections that allow priors and predictions to co-evolve to arrive at the best prediction. These results suggest that the filling-in process could be a manifestation of the general computational principle of hierarchical predictive coding of natural images. PMID:26959812

The rhythms of predictive coding? Pre-stimulus phase modulates the influence of shape perception on luminance judgments

PubMed Central

Han, Biao; VanRullen, Rufin

2017-01-01

Predictive coding is an influential model emphasizing interactions between feedforward and feedback signals. Here, we investigated the temporal dynamics of these interactions. Two gray disks with different versions of the same stimulus, one enabling predictive feedback (a 3D-shape) and one impeding it (random-lines), were simultaneously presented on the left and right of fixation. Human subjects judged the luminance of the two disks while EEG was recorded. The choice of 3D-shape or random-lines as the brighter disk was used to assess the influence of feedback signals on sensory processing in each trial (i.e., as a measure of post-stimulus predictive coding efficiency). Independently of the spatial response (left/right), we found that this choice fluctuated along with the pre-stimulus phase of two spontaneous oscillations: a ~5 Hz oscillation in contralateral frontal electrodes and a ~16 Hz oscillation in contralateral occipital electrodes. This pattern of results demonstrates that predictive coding is a rhythmic process, and suggests that it could take advantage of faster oscillations in low-level areas and slower oscillations in high-level areas. PMID:28262824

Poly(A) code analyses reveal key determinants for tissue-specific mRNA alternative polyadenylation

PubMed Central

Weng, Lingjie; Li, Yi; Xie, Xiaohui; Shi, Yongsheng

2016-01-01

mRNA alternative polyadenylation (APA) is a critical mechanism for post-transcriptional gene regulation and is often regulated in a tissue- and/or developmental stage-specific manner. An ultimate goal for the APA field has been to be able to computationally predict APA profiles under different physiological or pathological conditions. As a first step toward this goal, we have assembled a poly(A) code for predicting tissue-specific poly(A) sites (PASs). Based on a compendium of over 600 features that have known or potential roles in PAS selection, we have generated and refined a machine-learning algorithm using multiple high-throughput sequencing-based data sets of tissue-specific and constitutive PASs. This code can predict tissue-specific PASs with >85% accuracy. Importantly, by analyzing the prediction performance based on different RNA features, we found that PAS context, including the distance between alternative PASs and the relative position of a PAS within the gene, is a key feature for determining the susceptibility of a PAS to tissue-specific regulation. Our poly(A) code provides a useful tool for not only predicting tissue-specific APA regulation, but also for studying its underlying molecular mechanisms. PMID:27095026

Premotor neural correlates of predictive motor timing for speech production and hand movement: evidence for a temporal predictive code in the motor system.

PubMed

Johari, Karim; Behroozmand, Roozbeh

2017-05-01

The predictive coding model suggests that neural processing of sensory information is facilitated for temporally-predictable stimuli. This study investigated how temporal processing of visually-presented sensory cues modulates movement reaction time and neural activities in speech and hand motor systems. Event-related potentials (ERPs) were recorded in 13 subjects while they were visually-cued to prepare to produce a steady vocalization of a vowel sound or press a button in a randomized order, and to initiate the cued movement following the onset of a go signal on the screen. Experiment was conducted in two counterbalanced blocks in which the time interval between visual cue and go signal was temporally-predictable (fixed delay at 1000 ms) or unpredictable (variable between 1000 and 2000 ms). Results of the behavioral response analysis indicated that movement reaction time was significantly decreased for temporally-predictable stimuli in both speech and hand modalities. We identified premotor ERP activities with a left-lateralized parietal distribution for hand and a frontocentral distribution for speech that were significantly suppressed in response to temporally-predictable compared with unpredictable stimuli. The premotor ERPs were elicited approximately -100 ms before movement and were significantly correlated with speech and hand motor reaction times only in response to temporally-predictable stimuli. These findings suggest that the motor system establishes a predictive code to facilitate movement in response to temporally-predictable sensory stimuli. Our data suggest that the premotor ERP activities are robust neurophysiological biomarkers of such predictive coding mechanisms. These findings provide novel insights into the temporal processing mechanisms of speech and hand motor systems.

Application of TURBO-AE to Flutter Prediction: Aeroelastic Code Development

NASA Technical Reports Server (NTRS)

Hoyniak, Daniel; Simons, Todd A.; Stefko, George (Technical Monitor)

2001-01-01

The TURBO-AE program has been evaluated by comparing the obtained results to cascade rig data and to prediction made from various in-house programs. A high-speed fan cascade, a turbine cascade, a turbine cascade and a fan geometry that shower flutter in torsion mode were analyzed. The steady predictions for the high-speed fan cascade showed the TURBO-AE predictions to match in-house codes. However, the predictions did not match the measured blade surface data. Other researchers also reported similar disagreement with these data set. Unsteady runs for the fan configuration were not successful using TURBO-AE .

TEMPEST code simulations of hydrogen distribution in reactor containment structures. Final report

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

Trent, D.S.; Eyler, L.L.

The mass transport version of the TEMPEST computer code was used to simulate hydrogen distribution in geometric configurations relevant to reactor containment structures. Predicted results of Battelle-Frankfurt hydrogen distribution tests 1 to 6, and 12 are presented. Agreement between predictions and experimental data is good. Best agreement is obtained using the k-epsilon turbulence model in TEMPEST in flow cases where turbulent diffusion and stable stratification are dominant mechanisms affecting transport. The code's general analysis capabilities are summarized.

Initial Integration of Noise Prediction Tools for Acoustic Scattering Effects

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Burley, Casey L.; Tinetti, Ana; Rawls, John W.

2008-01-01

This effort provides an initial glimpse at NASA capabilities available in predicting the scattering of fan noise from a non-conventional aircraft configuration. The Aircraft NOise Prediction Program, Fast Scattering Code, and the Rotorcraft Noise Model were coupled to provide increased fidelity models of scattering effects on engine fan noise sources. The integration of these codes led to the identification of several keys issues entailed in applying such multi-fidelity approaches. In particular, for prediction at noise certification points, the inclusion of distributed sources leads to complications with the source semi-sphere approach. Computational resource requirements limit the use of the higher fidelity scattering code to predict radiated sound pressure levels for full scale configurations at relevant frequencies. And, the ability to more accurately represent complex shielding surfaces in current lower fidelity models is necessary for general application to scattering predictions. This initial step in determining the potential benefits/costs of these new methods over the existing capabilities illustrates a number of the issues that must be addressed in the development of next generation aircraft system noise prediction tools.

The NASA-LeRC wind turbine sound prediction code

NASA Technical Reports Server (NTRS)

Viterna, L. A.

1981-01-01

Since regular operation of the DOE/NASA MOD-1 wind turbine began in October 1979 about 10 nearby households have complained of noise from the machine. Development of the NASA-LeRC with turbine sound prediction code began in May 1980 as part of an effort to understand and reduce the noise generated by MOD-1. Tone sound levels predicted with this code are in generally good agreement with measured data taken in the vicinity MOD-1 wind turbine (less than 2 rotor diameters). Comparison in the far field indicates that propagation effects due to terrain and atmospheric conditions may be amplifying the actual sound levels by about 6 dB. Parametric analysis using the code has shown that the predominant contributions to MOD-1 rotor noise are: (1) the velocity deficit in the wake of the support tower; (2) the high rotor speed; and (3) off column operation.

Enhancement of the CAVE computer code. [aerodynamic heating package for nose cones and scramjet engine sidewalls

NASA Technical Reports Server (NTRS)

Rathjen, K. A.; Burk, H. O.

1983-01-01

The computer code CAVE (Conduction Analysis via Eigenvalues) is a convenient and efficient computer code for predicting two dimensional temperature histories within thermal protection systems for hypersonic vehicles. The capabilities of CAVE were enhanced by incorporation of the following features into the code: real gas effects in the aerodynamic heating predictions, geometry and aerodynamic heating package for analyses of cone shaped bodies, input option to change from laminar to turbulent heating predictions on leading edges, modification to account for reduction in adiabatic wall temperature with increase in leading sweep, geometry package for two dimensional scramjet engine sidewall, with an option for heat transfer to external and internal surfaces, print out modification to provide tables of select temperatures for plotting and storage, and modifications to the radiation calculation procedure to eliminate temperature oscillations induced by high heating rates. These new features are described.

Probability of coding of a DNA sequence: an algorithm to predict translated reading frames from their thermodynamic characteristics.

PubMed Central

Tramontano, A; Macchiato, M F

1986-01-01

An algorithm to determine the probability that a reading frame codifies for a protein is presented. It is based on the results of our previous studies on the thermodynamic characteristics of a translated reading frame. We also develop a prediction procedure to distinguish between coding and non-coding reading frames. The procedure is based on the characteristics of the putative product of the DNA sequence and not on periodicity characteristics of the sequence, so the prediction is not biased by the presence of overlapping translated reading frames or by the presence of translated reading frames on the complementary DNA strand. PMID:3753761

Jet Measurements for Development of Jet Noise Prediction Tools

NASA Technical Reports Server (NTRS)

Bridges, James E.

2006-01-01

The primary focus of my presentation is the development of the jet noise prediction code JeNo with most examples coming from the experimental work that drove the theoretical development and validation. JeNo is a statistical jet noise prediction code, based upon the Lilley acoustic analogy. Our approach uses time-average 2-D or 3-D mean and turbulent statistics of the flow as input. The output is source distributions and spectral directivity.

Interplanetary particles and fields, November 22 - December 6, 1977: Helios, Voyager, and IMP observations between 0.6 AU and 1.6 AU

NASA Technical Reports Server (NTRS)

Burlaga, L. F.; Lepping, R. P.; Weber, R.; Armstrong, T.; Goodrich, C.; Sullivan, J.; Gurnett, D.; Kellogg, P.; Keppler, E.; Mariani, F.

1979-01-01

The principal interplanetary events observed are described and analyzed. Three flow systems were observed: (1) a corotating stream and a stream interface associated with a coronal hole; (2) a shock wave and an energetic particle event associated with a 2-B flare; and (3) an isolated shock wave of uncertain origin. Data from 28 experiments and 6 spacecraft provide measurements of solar wind plasma, magnetic fields, plasma waves, radio waves, energetic electrons, and low energy protons.

Turbulent Flow Validation in the Helios Strand Solver

DTIC Science & Technology

2014-01-07

usual (̄) notation is omitted for simplicity). The pressure is obtained from the ideal gas equation of state given as: P = (γ−1) [ Et − 1 2 ρ ( u2 + v2...2. SA-RANS System The state vector and flux vectors including those of the SA model equation for three-dimensional flow are explicitly given as: u...number, PrT is the turbulent Prandtl number, and T is the temperature. The ideal gas equation of state , p = ρRT is used to close the equations . IV.A

Recent advances in hypersonic technology

NASA Technical Reports Server (NTRS)

Dwoyer, Douglas L.

1990-01-01

This paper will focus on recent advances in hypersonic aerodynamic prediction techniques. Current capabilities of existing numerical methods for predicting high Mach number flows will be discussed and shortcomings will be identified. Physical models available for inclusion into modern codes for predicting the effects of transition and turbulence will also be outlined and their limitations identified. Chemical reaction models appropriate to high-speed flows will be addressed, and the impact of their inclusion in computational fluid dynamics codes will be discussed. Finally, the problem of validating predictive techniques for high Mach number flows will be addressed.

An evaluation of a computer code based on linear acoustic theory for predicting helicopter main rotor noise

NASA Astrophysics Data System (ADS)

Davis, S. J.; Egolf, T. A.

1980-07-01

Acoustic characteristics predicted using a recently developed computer code were correlated with measured acoustic data for two helicopter rotors. The analysis, is based on a solution of the Ffowcs-Williams-Hawkings (FW-H) equation and includes terms accounting for both the thickness and loading components of the rotational noise. Computations are carried out in the time domain and assume free field conditions. Results of the correlation show that the Farrassat/Nystrom analysis, when using predicted airload data as input, yields fair but encouraging correlation for the first 6 harmonics of blade passage. It also suggests that although the analysis represents a valuable first step towards developing a truly comprehensive helicopter rotor noise prediction capability, further work remains to be done identifying and incorporating additional noise mechanisms into the code.

Application of a Two-dimensional Unsteady Viscous Analysis Code to a Supersonic Throughflow Fan Stage

NASA Technical Reports Server (NTRS)

Steinke, Ronald J.

1989-01-01

The Rai ROTOR1 code for two-dimensional, unsteady viscous flow analysis was applied to a supersonic throughflow fan stage design. The axial Mach number for this fan design increases from 2.0 at the inlet to 2.9 at the outlet. The Rai code uses overlapped O- and H-grids that are appropriately packed. The Rai code was run on a Cray XMP computer; then data postprocessing and graphics were performed to obtain detailed insight into the stage flow. The large rotor wakes uniformly traversed the rotor-stator interface and dispersed as they passed through the stator passage. Only weak blade shock losses were computerd, which supports the design goals. High viscous effects caused large blade wakes and a low fan efficiency. Rai code flow predictions were essentially steady for the rotor, and they compared well with Chima rotor viscous code predictions based on a C-grid of similar density.

High-fidelity plasma codes for burn physics

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

Cooley, James; Graziani, Frank; Marinak, Marty

Accurate predictions of equation of state (EOS), ionic and electronic transport properties are of critical importance for high-energy-density plasma science. Transport coefficients inform radiation-hydrodynamic codes and impact diagnostic interpretation, which in turn impacts our understanding of the development of instabilities, the overall energy balance of burning plasmas, and the efficacy of self-heating from charged-particle stopping. Important processes include thermal and electrical conduction, electron-ion coupling, inter-diffusion, ion viscosity, and charged particle stopping. However, uncertainties in these coefficients are not well established. Fundamental plasma science codes, also called high-fidelity plasma codes, are a relatively recent computational tool that augments both experimental datamore » and theoretical foundations of transport coefficients. This paper addresses the current status of HFPC codes and their future development, and the potential impact they play in improving the predictive capability of the multi-physics hydrodynamic codes used in HED design.« less

Toward a CFD nose-to-tail capability - Hypersonic unsteady Navier-Stokes code validation

NASA Technical Reports Server (NTRS)

Edwards, Thomas A.; Flores, Jolen

1989-01-01

Computational fluid dynamics (CFD) research for hypersonic flows presents new problems in code validation because of the added complexity of the physical models. This paper surveys code validation procedures applicable to hypersonic flow models that include real gas effects. The current status of hypersonic CFD flow analysis is assessed with the Compressible Navier-Stokes (CNS) code as a case study. The methods of code validation discussed to beyond comparison with experimental data to include comparisons with other codes and formulations, component analyses, and estimation of numerical errors. Current results indicate that predicting hypersonic flows of perfect gases and equilibrium air are well in hand. Pressure, shock location, and integrated quantities are relatively easy to predict accurately, while surface quantities such as heat transfer are more sensitive to the solution procedure. Modeling transition to turbulence needs refinement, though preliminary results are promising.

Mechanistic prediction of fission-gas behavior during in-cell transient heating tests on LWR fuel using the GRASS-SST and FASTGRASS computer codes

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

Rest, J; Gehl, S M

1979-01-01

GRASS-SST and FASTGRASS are mechanistic computer codes for predicting fission-gas behavior in UO/sub 2/-base fuels during steady-state and transient conditions. FASTGRASS was developed in order to satisfy the need for a fast-running alternative to GRASS-SST. Althrough based on GRASS-SST, FASTGRASS is approximately an order of magnitude quicker in execution. The GRASS-SST transient analysis has evolved through comparisons of code predictions with the fission-gas release and physical phenomena that occur during reactor operation and transient direct-electrical-heating (DEH) testing of irradiated light-water reactor fuel. The FASTGRASS calculational procedure is described in this paper, along with models of key physical processes included inmore » both FASTGRASS and GRASS-SST. Predictions of fission-gas release obtained from GRASS-SST and FASTGRASS analyses are compared with experimental observations from a series of DEH tests. The major conclusions is that the computer codes should include an improved model for the evolution of the grain-edge porosity.« less

Signal Prediction With Input Identification

NASA Technical Reports Server (NTRS)

Juang, Jer-Nan; Chen, Ya-Chin

1999-01-01

A novel coding technique is presented for signal prediction with applications including speech coding, system identification, and estimation of input excitation. The approach is based on the blind equalization method for speech signal processing in conjunction with the geometric subspace projection theory to formulate the basic prediction equation. The speech-coding problem is often divided into two parts, a linear prediction model and excitation input. The parameter coefficients of the linear predictor and the input excitation are solved simultaneously and recursively by a conventional recursive least-squares algorithm. The excitation input is computed by coding all possible outcomes into a binary codebook. The coefficients of the linear predictor and excitation, and the index of the codebook can then be used to represent the signal. In addition, a variable-frame concept is proposed to block the same excitation signal in sequence in order to reduce the storage size and increase the transmission rate. The results of this work can be easily extended to the problem of disturbance identification. The basic principles are outlined in this report and differences from other existing methods are discussed. Simulations are included to demonstrate the proposed method.

Comparisons of survival predictions using survival risk ratios based on International Classification of Diseases, Ninth Revision and Abbreviated Injury Scale trauma diagnosis codes.

PubMed

Clarke, John R; Ragone, Andrew V; Greenwald, Lloyd

2005-09-01

We conducted a comparison of methods for predicting survival using survival risk ratios (SRRs), including new comparisons based on International Classification of Diseases, Ninth Revision (ICD-9) versus Abbreviated Injury Scale (AIS) six-digit codes. From the Pennsylvania trauma center's registry, all direct trauma admissions were collected through June 22, 1999. Patients with no comorbid medical diagnoses and both ICD-9 and AIS injury codes were used for comparisons based on a single set of data. SRRs for ICD-9 and then for AIS diagnostic codes were each calculated two ways: from the survival rate of patients with each diagnosis and when each diagnosis was an isolated diagnosis. Probabilities of survival for the cohort were calculated using each set of SRRs by the multiplicative ICISS method and, where appropriate, the minimum SRR method. These prediction sets were then internally validated against actual survival by the Hosmer-Lemeshow goodness-of-fit statistic. The 41,364 patients had 1,224 different ICD-9 injury diagnoses in 32,261 combinations and 1,263 corresponding AIS injury diagnoses in 31,755 combinations, ranging from 1 to 27 injuries per patient. All conventional ICD-9-based combinations of SRRs and methods had better Hosmer-Lemeshow goodness-of-fit statistic fits than their AIS-based counterparts. The minimum SRR method produced better calibration than the multiplicative methods, presumably because it did not magnify inaccuracies in the SRRs that might occur with multiplication. Predictions of survival based on anatomic injury alone can be performed using ICD-9 codes, with no advantage from extra coding of AIS diagnoses. Predictions based on the single worst SRR were closer to actual outcomes than those based on multiplying SRRs.

TRAP/SEE Code Users Manual for Predicting Trapped Radiation Environments

NASA Technical Reports Server (NTRS)

Armstrong, T. W.; Colborn, B. L.

2000-01-01

TRAP/SEE is a PC-based computer code with a user-friendly interface which predicts the ionizing radiation exposure of spacecraft having orbits in the Earth's trapped radiation belts. The code incorporates the standard AP8 and AE8 trapped proton and electron models but also allows application of an improved database interpolation method. The code treats low-Earth as well as highly-elliptical Earth orbits, taking into account trajectory perturbations due to gravitational forces from the Moon and Sun, atmospheric drag, and solar radiation pressure. Orbit-average spectra, peak spectra per orbit, and instantaneous spectra at points along the orbit trajectory are calculated. Described in this report are the features, models, model limitations and uncertainties, input and output descriptions, and example calculations and applications for the TRAP/SEE code.

Fast H.264/AVC FRExt intra coding using belief propagation.

PubMed

Milani, Simone

2011-01-01

In the H.264/AVC FRExt coder, the coding performance of Intra coding significantly overcomes the previous still image coding standards, like JPEG2000, thanks to a massive use of spatial prediction. Unfortunately, the adoption of an extensive set of predictors induces a significant increase of the computational complexity required by the rate-distortion optimization routine. The paper presents a complexity reduction strategy that aims at reducing the computational load of the Intra coding with a small loss in the compression performance. The proposed algorithm relies on selecting a reduced set of prediction modes according to their probabilities, which are estimated adopting a belief-propagation procedure. Experimental results show that the proposed method permits saving up to 60 % of the coding time required by an exhaustive rate-distortion optimization method with a negligible loss in performance. Moreover, it permits an accurate control of the computational complexity unlike other methods where the computational complexity depends upon the coded sequence.

An Interoceptive Predictive Coding Model of Conscious Presence

PubMed Central

Seth, Anil K.; Suzuki, Keisuke; Critchley, Hugo D.

2011-01-01

We describe a theoretical model of the neurocognitive mechanisms underlying conscious presence and its disturbances. The model is based on interoceptive prediction error and is informed by predictive models of agency, general models of hierarchical predictive coding and dopaminergic signaling in cortex, the role of the anterior insular cortex (AIC) in interoception and emotion, and cognitive neuroscience evidence from studies of virtual reality and of psychiatric disorders of presence, specifically depersonalization/derealization disorder. The model associates presence with successful suppression by top-down predictions of informative interoceptive signals evoked by autonomic control signals and, indirectly, by visceral responses to afferent sensory signals. The model connects presence to agency by allowing that predicted interoceptive signals will depend on whether afferent sensory signals are determined, by a parallel predictive-coding mechanism, to be self-generated or externally caused. Anatomically, we identify the AIC as the likely locus of key neural comparator mechanisms. Our model integrates a broad range of previously disparate evidence, makes predictions for conjoint manipulations of agency and presence, offers a new view of emotion as interoceptive inference, and represents a step toward a mechanistic account of a fundamental phenomenological property of consciousness. PMID:22291673

Fan Noise Prediction System Development: Source/Radiation Field Coupling and Workstation Conversion for the Acoustic Radiation Code

NASA Technical Reports Server (NTRS)

Meyer, H. D.

1993-01-01

The Acoustic Radiation Code (ARC) is a finite element program used on the IBM mainframe to predict far-field acoustic radiation from a turbofan engine inlet. In this report, requirements for developers of internal aerodynamic codes regarding use of their program output an input for the ARC are discussed. More specifically, the particular input needed from the Bolt, Beranek and Newman/Pratt and Whitney (turbofan source noise generation) Code (BBN/PWC) is described. In a separate analysis, a method of coupling the source and radiation models, that recognizes waves crossing the interface in both directions, has been derived. A preliminary version of the coupled code has been developed and used for initial evaluation of coupling issues. Results thus far have shown that reflection from the inlet is sufficient to indicate that full coupling of the source and radiation fields is needed for accurate noise predictions ' Also, for this contract, the ARC has been modified for use on the Sun and Silicon Graphics Iris UNIX workstations. Changes and additions involved in this effort are described in an appendix.

Dynamic divisive normalization predicts time-varying value coding in decision-related circuits.

PubMed

Louie, Kenway; LoFaro, Thomas; Webb, Ryan; Glimcher, Paul W

2014-11-26

Normalization is a widespread neural computation, mediating divisive gain control in sensory processing and implementing a context-dependent value code in decision-related frontal and parietal cortices. Although decision-making is a dynamic process with complex temporal characteristics, most models of normalization are time-independent and little is known about the dynamic interaction of normalization and choice. Here, we show that a simple differential equation model of normalization explains the characteristic phasic-sustained pattern of cortical decision activity and predicts specific normalization dynamics: value coding during initial transients, time-varying value modulation, and delayed onset of contextual information. Empirically, we observe these predicted dynamics in saccade-related neurons in monkey lateral intraparietal cortex. Furthermore, such models naturally incorporate a time-weighted average of past activity, implementing an intrinsic reference-dependence in value coding. These results suggest that a single network mechanism can explain both transient and sustained decision activity, emphasizing the importance of a dynamic view of normalization in neural coding. Copyright © 2014 the authors 0270-6474/14/3416046-12$15.00/0.

Aeroacoustic Codes For Rotor Harmonic and BVI Noise--CAMRAD.Mod1/HIRES

NASA Technical Reports Server (NTRS)

Brooks, Thomas F.; Boyd, D. Douglas, Jr.; Burley, Casey L.; Jolly, J. Ralph, Jr.

1996-01-01

This paper presents a status of non-CFD aeroacoustic codes at NASA Langley Research Center for the prediction of helicopter harmonic and Blade-Vortex Interaction (BVI) noise. The prediction approach incorporates three primary components: CAMRAD.Mod1 - a substantially modified version of the performance/trim/wake code CAMRAD; HIRES - a high resolution blade loads post-processor; and WOPWOP - an acoustic code. The functional capabilities and physical modeling in CAMRAD.Mod1/HIRES will be summarized and illustrated. A new multi-core roll-up wake modeling approach is introduced and validated. Predictions of rotor wake and radiated noise are compared with to the results of the HART program, a model BO-105 windtunnel test at the DNW in Europe. Additional comparisons are made to results from a DNW test of a contemporary design four-bladed rotor, as well as from a Langley test of a single proprotor (tiltrotor) three-bladed model configuration. Because the method is shown to help eliminate the necessity of guesswork in setting code parameters between different rotor configurations, it should prove useful as a rotor noise design tool.

Overview of NASA Multi-dimensional Stirling Convertor Code Development and Validation Effort

NASA Technical Reports Server (NTRS)

Tew, Roy C.; Cairelli, James E.; Ibrahim, Mounir B.; Simon, Terrence W.; Gedeon, David

2002-01-01

A NASA grant has been awarded to Cleveland State University (CSU) to develop a multi-dimensional (multi-D) Stirling computer code with the goals of improving loss predictions and identifying component areas for improvements. The University of Minnesota (UMN) and Gedeon Associates are teamed with CSU. Development of test rigs at UMN and CSU and validation of the code against test data are part of the effort. The one-dimensional (1-D) Stirling codes used for design and performance prediction do not rigorously model regions of the working space where abrupt changes in flow area occur (such as manifolds and other transitions between components). Certain hardware experiences have demonstrated large performance gains by varying manifolds and heat exchanger designs to improve flow distributions in the heat exchangers. 1-D codes were not able to predict these performance gains. An accurate multi-D code should improve understanding of the effects of area changes along the main flow axis, sensitivity of performance to slight changes in internal geometry, and, in general, the understanding of various internal thermodynamic losses. The commercial CFD-ACE code has been chosen for development of the multi-D code. This 2-D/3-D code has highly developed pre- and post-processors, and moving boundary capability. Preliminary attempts at validation of CFD-ACE models of MIT gas spring and "two space" test rigs were encouraging. Also, CSU's simulations of the UMN oscillating-flow fig compare well with flow visualization results from UMN. A complementary Department of Energy (DOE) Regenerator Research effort is aiding in development of regenerator matrix models that will be used in the multi-D Stirling code. This paper reports on the progress and challenges of this

Survey of adaptive image coding techniques

NASA Technical Reports Server (NTRS)

Habibi, A.

1977-01-01

The general problem of image data compression is discussed briefly with attention given to the use of Karhunen-Loeve transforms, suboptimal systems, and block quantization. A survey is then conducted encompassing the four categories of adaptive systems: (1) adaptive transform coding (adaptive sampling, adaptive quantization, etc.), (2) adaptive predictive coding (adaptive delta modulation, adaptive DPCM encoding, etc.), (3) adaptive cluster coding (blob algorithms and the multispectral cluster coding technique), and (4) adaptive entropy coding.

Does the Holland Code Predict Job Satisfaction and Productivity in Clothing Factory Workers?

ERIC Educational Resources Information Center

Heesacker, Martin; And Others

1988-01-01

Administered Self-Directed Search to sewing machine operators to determine Holland code, and assessed work productivity, job satisfaction, absenteeism, and insurance claims. Most workers were of the Social code. Social subjects were the most satisfied, Conventional and Realistic subjects next, and subjects of other codes less so. Productivity of…

Supplementing Public Health Inspection via Social Media

PubMed Central

Schomberg, John P.; Haimson, Oliver L.; Hayes, Gillian R.; Anton-Culver, Hoda

2016-01-01

Foodborne illness is prevented by inspection and surveillance conducted by health departments across America. Appropriate restaurant behavior is enforced and monitored via public health inspections. However, surveillance coverage provided by state and local health departments is insufficient in preventing the rising number of foodborne illness outbreaks. To address this need for improved surveillance coverage we conducted a supplementary form of public health surveillance using social media data: Yelp.com restaurant reviews in the city of San Francisco. Yelp is a social media site where users post reviews and rate restaurants they have personally visited. Presence of keywords related to health code regulations and foodborne illness symptoms, number of restaurant reviews, number of Yelp stars, and restaurant price range were included in a model predicting a restaurant’s likelihood of health code violation measured by the assigned San Francisco public health code rating. For a list of major health code violations see (S1 Table). We built the predictive model using 71,360 Yelp reviews of restaurants in the San Francisco Bay Area. The predictive model was able to predict health code violations in 78% of the restaurants receiving serious citations in our pilot study of 440 restaurants. Training and validation data sets each pulled data from 220 restaurants in San Francisco. Keyword analysis of free text within Yelp not only improved detection of high-risk restaurants, but it also served to identify specific risk factors related to health code violation. To further validate our model we applied the model generated in our pilot study to Yelp data from 1,542 restaurants in San Francisco. The model achieved 91% sensitivity 74% specificity, area under the receiver operator curve of 98%, and positive predictive value of 29% (given a substandard health code rating prevalence of 10%). When our model was applied to restaurant reviews in New York City we achieved 74% sensitivity, 54% specificity, area under the receiver operator curve of 77%, and positive predictive value of 25% (given a prevalence of 12%). Model accuracy improved when reviews ranked highest by Yelp were utilized. Our results indicate that public health surveillance can be improved by using social media data to identify restaurants at high risk for health code violation. Additionally, using highly ranked Yelp reviews improves predictive power and limits the number of reviews needed to generate prediction. Use of this approach as an adjunct to current risk ranking of restaurants prior to inspection may enhance detection of those restaurants participating in high risk practices that may have gone previously undetected. This model represents a step forward in the integration of social media into meaningful public health interventions. PMID:27023681

Supplementing Public Health Inspection via Social Media.

PubMed

Schomberg, John P; Haimson, Oliver L; Hayes, Gillian R; Anton-Culver, Hoda

2016-01-01

Foodborne illness is prevented by inspection and surveillance conducted by health departments across America. Appropriate restaurant behavior is enforced and monitored via public health inspections. However, surveillance coverage provided by state and local health departments is insufficient in preventing the rising number of foodborne illness outbreaks. To address this need for improved surveillance coverage we conducted a supplementary form of public health surveillance using social media data: Yelp.com restaurant reviews in the city of San Francisco. Yelp is a social media site where users post reviews and rate restaurants they have personally visited. Presence of keywords related to health code regulations and foodborne illness symptoms, number of restaurant reviews, number of Yelp stars, and restaurant price range were included in a model predicting a restaurant's likelihood of health code violation measured by the assigned San Francisco public health code rating. For a list of major health code violations see (S1 Table). We built the predictive model using 71,360 Yelp reviews of restaurants in the San Francisco Bay Area. The predictive model was able to predict health code violations in 78% of the restaurants receiving serious citations in our pilot study of 440 restaurants. Training and validation data sets each pulled data from 220 restaurants in San Francisco. Keyword analysis of free text within Yelp not only improved detection of high-risk restaurants, but it also served to identify specific risk factors related to health code violation. To further validate our model we applied the model generated in our pilot study to Yelp data from 1,542 restaurants in San Francisco. The model achieved 91% sensitivity 74% specificity, area under the receiver operator curve of 98%, and positive predictive value of 29% (given a substandard health code rating prevalence of 10%). When our model was applied to restaurant reviews in New York City we achieved 74% sensitivity, 54% specificity, area under the receiver operator curve of 77%, and positive predictive value of 25% (given a prevalence of 12%). Model accuracy improved when reviews ranked highest by Yelp were utilized. Our results indicate that public health surveillance can be improved by using social media data to identify restaurants at high risk for health code violation. Additionally, using highly ranked Yelp reviews improves predictive power and limits the number of reviews needed to generate prediction. Use of this approach as an adjunct to current risk ranking of restaurants prior to inspection may enhance detection of those restaurants participating in high risk practices that may have gone previously undetected. This model represents a step forward in the integration of social media into meaningful public health interventions.

Neural Elements for Predictive Coding.

PubMed

Shipp, Stewart

2016-01-01

Predictive coding theories of sensory brain function interpret the hierarchical construction of the cerebral cortex as a Bayesian, generative model capable of predicting the sensory data consistent with any given percept. Predictions are fed backward in the hierarchy and reciprocated by prediction error in the forward direction, acting to modify the representation of the outside world at increasing levels of abstraction, and so to optimize the nature of perception over a series of iterations. This accounts for many 'illusory' instances of perception where what is seen (heard, etc.) is unduly influenced by what is expected, based on past experience. This simple conception, the hierarchical exchange of prediction and prediction error, confronts a rich cortical microcircuitry that is yet to be fully documented. This article presents the view that, in the current state of theory and practice, it is profitable to begin a two-way exchange: that predictive coding theory can support an understanding of cortical microcircuit function, and prompt particular aspects of future investigation, whilst existing knowledge of microcircuitry can, in return, influence theoretical development. As an example, a neural inference arising from the earliest formulations of predictive coding is that the source populations of forward and backward pathways should be completely separate, given their functional distinction; this aspect of circuitry - that neurons with extrinsically bifurcating axons do not project in both directions - has only recently been confirmed. Here, the computational architecture prescribed by a generalized (free-energy) formulation of predictive coding is combined with the classic 'canonical microcircuit' and the laminar architecture of hierarchical extrinsic connectivity to produce a template schematic, that is further examined in the light of (a) updates in the microcircuitry of primate visual cortex, and (b) rapid technical advances made possible by transgenic neural engineering in the mouse. The exercise highlights a number of recurring themes, amongst them the consideration of interneuron diversity as a spur to theoretical development and the potential for specifying a pyramidal neuron's function by its individual 'connectome,' combining its extrinsic projection (forward, backward or subcortical) with evaluation of its intrinsic network (e.g., unidirectional versus bidirectional connections with other pyramidal neurons).

Neural Elements for Predictive Coding

PubMed Central

Shipp, Stewart

2016-01-01

Predictive coding theories of sensory brain function interpret the hierarchical construction of the cerebral cortex as a Bayesian, generative model capable of predicting the sensory data consistent with any given percept. Predictions are fed backward in the hierarchy and reciprocated by prediction error in the forward direction, acting to modify the representation of the outside world at increasing levels of abstraction, and so to optimize the nature of perception over a series of iterations. This accounts for many ‘illusory’ instances of perception where what is seen (heard, etc.) is unduly influenced by what is expected, based on past experience. This simple conception, the hierarchical exchange of prediction and prediction error, confronts a rich cortical microcircuitry that is yet to be fully documented. This article presents the view that, in the current state of theory and practice, it is profitable to begin a two-way exchange: that predictive coding theory can support an understanding of cortical microcircuit function, and prompt particular aspects of future investigation, whilst existing knowledge of microcircuitry can, in return, influence theoretical development. As an example, a neural inference arising from the earliest formulations of predictive coding is that the source populations of forward and backward pathways should be completely separate, given their functional distinction; this aspect of circuitry – that neurons with extrinsically bifurcating axons do not project in both directions – has only recently been confirmed. Here, the computational architecture prescribed by a generalized (free-energy) formulation of predictive coding is combined with the classic ‘canonical microcircuit’ and the laminar architecture of hierarchical extrinsic connectivity to produce a template schematic, that is further examined in the light of (a) updates in the microcircuitry of primate visual cortex, and (b) rapid technical advances made possible by transgenic neural engineering in the mouse. The exercise highlights a number of recurring themes, amongst them the consideration of interneuron diversity as a spur to theoretical development and the potential for specifying a pyramidal neuron’s function by its individual ‘connectome,’ combining its extrinsic projection (forward, backward or subcortical) with evaluation of its intrinsic network (e.g., unidirectional versus bidirectional connections with other pyramidal neurons). PMID:27917138

Orbitofrontal Cortex Signals Expected Outcomes with Predictive Codes When Stable Contingencies Promote the Integration of Reward History

PubMed Central

Shapiro, Matthew L.

2017-01-01

Memory can inform goal-directed behavior by linking current opportunities to past outcomes. The orbitofrontal cortex (OFC) may guide value-based responses by integrating the history of stimulus–reward associations into expected outcomes, representations of predicted hedonic value and quality. Alternatively, the OFC may rapidly compute flexible “online” reward predictions by associating stimuli with the latest outcome. OFC neurons develop predictive codes when rats learn to associate arbitrary stimuli with outcomes, but the extent to which predictive coding depends on most recent events and the integrated history of rewards is unclear. To investigate how reward history modulates OFC activity, we recorded OFC ensembles as rats performed spatial discriminations that differed only in the number of rewarded trials between goal reversals. The firing rate of single OFC neurons distinguished identical behaviors guided by different goals. When >20 rewarded trials separated goal switches, OFC ensembles developed stable and anticorrelated population vectors that predicted overall choice accuracy and the goal selected in single trials. When <10 rewarded trials separated goal switches, OFC population vectors decorrelated rapidly after each switch, but did not develop anticorrelated firing patterns or predict choice accuracy. The results show that, whereas OFC signals respond rapidly to contingency changes, they predict choices only when reward history is relatively stable, suggesting that consecutive rewarded episodes are needed for OFC computations that integrate reward history into expected outcomes. SIGNIFICANCE STATEMENT Adapting to changing contingencies and making decisions engages the orbitofrontal cortex (OFC). Previous work shows that OFC function can either improve or impair learning depending on reward stability, suggesting that OFC guides behavior optimally when contingencies apply consistently. The mechanisms that link reward history to OFC computations remain obscure. Here, we examined OFC unit activity as rodents performed tasks controlled by contingencies that varied reward history. When contingencies were stable, OFC neurons signaled past, present, and pending events; when contingencies were unstable, past and present coding persisted, but predictive coding diminished. The results suggest that OFC mechanisms require stable contingencies across consecutive episodes to integrate reward history, represent predicted outcomes, and inform goal-directed choices. PMID:28115481

Analysis Code - Data Analysis in 'Leveraging Multiple Statistical Methods for Inverse Prediction in Nuclear Forensics Applications' (LMSMIPNFA) v. 1.0

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

Lewis, John R

R code that performs the analysis of a data set presented in the paper ‘Leveraging Multiple Statistical Methods for Inverse Prediction in Nuclear Forensics Applications’ by Lewis, J., Zhang, A., Anderson-Cook, C. It provides functions for doing inverse predictions in this setting using several different statistical methods. The data set is a publicly available data set from a historical Plutonium production experiment.

Demonstration of Hybrid DSMC-CFD Capability for Nonequilibrium Reacting Flow

DTIC Science & Technology

2018-02-09

Lens-XX facility. This flow was chosen since a recent blind-code validation exercise revealed differences in CFD predictions and experimental data... experimental data that could be due to rarefied flow effects. The CFD solutions (using the US3D code) were run with no-slip boundary conditions and with...excellent agreement with that predicted by CFD. This implies that the dif- ference between CFD predictions and experimental data is not due to rarefied

The power induced effects module: A FORTRAN code which estimates lift increments due to power induced effects for V/STOL flight

NASA Technical Reports Server (NTRS)

Sandlin, Doral R.; Howard, Kipp E.

1991-01-01

A user friendly FORTRAN code that can be used for preliminary design of V/STOL aircraft is described. The program estimates lift increments, due to power induced effects, encountered by aircraft in V/STOL flight. These lift increments are calculated using empirical relations developed from wind tunnel tests and are due to suckdown, fountain, ground vortex, jet wake, and the reaction control system. The code can be used as a preliminary design tool along with NASA Ames' Aircraft Synthesis design code or as a stand-alone program for V/STOL aircraft designers. The Power Induced Effects (PIE) module was validated using experimental data and data computed from lift increment routines. Results are presented for many flat plate models along with the McDonnell Aircraft Company's MFVT (mixed flow vectored thrust) V/STOL preliminary design and a 15 percent scale model of the YAV-8B Harrier V/STOL aircraft. Trends and magnitudes of lift increments versus aircraft height above the ground were predicted well by the PIE module. The code also provided good predictions of the magnitudes of lift increments versus aircraft forward velocity. More experimental results are needed to determine how well the code predicts lift increments as they vary with jet deflection angle and angle of attack. The FORTRAN code is provided in the appendix.

Radiation from advanced solid rocket motor plumes

NASA Technical Reports Server (NTRS)

Farmer, Richard C.; Smith, Sheldon D.; Myruski, Brian L.

1994-01-01

The overall objective of this study was to develop an understanding of solid rocket motor (SRM) plumes in sufficient detail to accurately explain the majority of plume radiation test data. Improved flowfield and radiation analysis codes were developed to accurately and efficiently account for all the factors which effect radiation heating from rocket plumes. These codes were verified by comparing predicted plume behavior with measured NASA/MSFC ASRM test data. Upon conducting a thorough review of the current state-of-the-art of SRM plume flowfield and radiation prediction methodology and the pertinent data base, the following analyses were developed for future design use. The NOZZRAD code was developed for preliminary base heating design and Al2O3 particle optical property data evaluation using a generalized two-flux solution to the radiative transfer equation. The IDARAD code was developed for rapid evaluation of plume radiation effects using the spherical harmonics method of differential approximation to the radiative transfer equation. The FDNS CFD code with fully coupled Euler-Lagrange particle tracking was validated by comparison to predictions made with the industry standard RAMP code for SRM nozzle flowfield analysis. The FDNS code provides the ability to analyze not only rocket nozzle flow, but also axisymmetric and three-dimensional plume flowfields with state-of-the-art CFD methodology. Procedures for conducting meaningful thermo-vision camera studies were developed.

User's manual for the time-dependent INERTIA code

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

Bailey, A.W.; Bennett, R.B.

1985-01-01

The time-dependent INERTIA code is described. This code models the effects of neutral beam momentum input in tokamaks as predicted by the time-dependent formulation of the Stacey-Sigmar formalism. The operation and architecture of the code are described, as are the supplementary plotting and impurity line radiation routines. A short description of the steady-state version of the INERTIA code is also provided.

Validity of the International Classification of Diseases 10th revision code for hospitalisation with hyponatraemia in elderly patients

PubMed Central

Gandhi, Sonja; Shariff, Salimah Z; Fleet, Jamie L; Weir, Matthew A; Jain, Arsh K; Garg, Amit X

2012-01-01

Objective To evaluate the validity of the International Classification of Diseases, 10th Revision (ICD-10) diagnosis code for hyponatraemia (E87.1) in two settings: at presentation to the emergency department and at hospital admission. Design Population-based retrospective validation study. Setting Twelve hospitals in Southwestern Ontario, Canada, from 2003 to 2010. Participants Patients aged 66 years and older with serum sodium laboratory measurements at presentation to the emergency department (n=64 581) and at hospital admission (n=64 499). Main outcome measures Sensitivity, specificity, positive predictive value and negative predictive value comparing various ICD-10 diagnostic coding algorithms for hyponatraemia to serum sodium laboratory measurements (reference standard). Median serum sodium values comparing patients who were code positive and code negative for hyponatraemia. Results The sensitivity of hyponatraemia (defined by a serum sodium ≤132 mmol/l) for the best-performing ICD-10 coding algorithm was 7.5% at presentation to the emergency department (95% CI 7.0% to 8.2%) and 10.6% at hospital admission (95% CI 9.9% to 11.2%). Both specificities were greater than 99%. In the two settings, the positive predictive values were 96.4% (95% CI 94.6% to 97.6%) and 82.3% (95% CI 80.0% to 84.4%), while the negative predictive values were 89.2% (95% CI 89.0% to 89.5%) and 87.1% (95% CI 86.8% to 87.4%). In patients who were code positive for hyponatraemia, the median (IQR) serum sodium measurements were 123 (119–126) mmol/l and 125 (120–130) mmol/l in the two settings. In code negative patients, the measurements were 138 (136–140) mmol/l and 137 (135–139) mmol/l. Conclusions The ICD-10 diagnostic code for hyponatraemia differentiates between two groups of patients with distinct serum sodium measurements at both presentation to the emergency department and at hospital admission. However, these codes underestimate the true incidence of hyponatraemia due to low sensitivity. PMID:23274673

Polymerization of non-complementary RNA: systematic symmetric nucleotide exchanges mainly involving uracil produce mitochondrial RNA transcripts coding for cryptic overlapping genes.

PubMed

Seligmann, Hervé

2013-03-01

Usual DNA→RNA transcription exchanges T→U. Assuming different systematic symmetric nucleotide exchanges during translation, some GenBank RNAs match exactly human mitochondrial sequences (exchange rules listed in decreasing transcript frequencies): C↔U, A↔U, A↔U+C↔G (two nucleotide pairs exchanged), G↔U, A↔G, C↔G, none for A↔C, A↔G+C↔U, and A↔C+G↔U. Most unusual transcripts involve exchanging uracil. Independent measures of rates of rare replicational enzymatic DNA nucleotide misinsertions predict frequencies of RNA transcripts systematically exchanging the corresponding misinserted nucleotides. Exchange transcripts self-hybridize less than other gene regions, self-hybridization increases with length, suggesting endoribonuclease-limited elongation. Blast detects stop codon depleted putative protein coding overlapping genes within exchange-transcribed mitochondrial genes. These align with existing GenBank proteins (mainly metazoan origins, prokaryotic and viral origins underrepresented). These GenBank proteins frequently interact with RNA/DNA, are membrane transporters, or are typical of mitochondrial metabolism. Nucleotide exchange transcript frequencies increase with overlapping gene densities and stop densities, indicating finely tuned counterbalancing regulation of expression of systematic symmetric nucleotide exchange-encrypted proteins. Such expression necessitates combined activities of suppressor tRNAs matching stops, and nucleotide exchange transcription. Two independent properties confirm predicted exchanged overlap coding genes: discrepancy of third codon nucleotide contents from replicational deamination gradients, and codon usage according to circular code predictions. Predictions from both properties converge, especially for frequent nucleotide exchange types. Nucleotide exchanging transcription apparently increases coding densities of protein coding genes without lengthening genomes, revealing unsuspected functional DNA coding potential. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Analysis of film cooling in rocket nozzles

NASA Technical Reports Server (NTRS)

Woodbury, Keith A.

1992-01-01

Computational Fluid Dynamics (CFD) programs are customarily used to compute details of a flow field, such as velocity fields or species concentrations. Generally they are not used to determine the resulting conditions at a solid boundary such as wall shear stress or heat flux. However, determination of this information should be within the capability of a CFD code, as the code supposedly contains appropriate models for these wall conditions. Before such predictions from CFD analyses can be accepted, the credibility of the CFD codes upon which they are based must be established. This report details the progress made in constructing a CFD model to predict the heat transfer to the wall in a film cooled rocket nozzle. Specifically, the objective of this work is to use the NASA code FDNS to predict the heat transfer which will occur during the upcoming hot-firing of the Pratt & Whitney 40K subscale nozzle (1Q93). Toward this end, an M = 3 wall jet is considered, and the resulting heat transfer to the wall is computed. The values are compared against experimental data available in Reference 1. Also, FDNS's ability to compute heat flux in a reacting flow will be determined by comparing the code's predictions against calorimeter data from the hot firing of a 40K combustor. The process of modeling the flow of combusting gases through the Pratt & Whitney 40K subscale combustor and nozzle is outlined. What follows in this report is a brief description of the FDNS code, with special emphasis on how it handles solid wall boundary conditions. The test cases and some FDNS solution are presented next, along with comparison to experimental data. The process of modeling the flow through a chamber and a nozzle using the FDNS code will also be outlined.

A transonic wind tunnel wall interference prediction code

NASA Technical Reports Server (NTRS)

Phillips, Pamela S.; Waggoner, Edgar G.

1988-01-01

A small disturbance transonic wall interference prediction code has been developed that is capable of modeling solid, open, perforated, and slotted walls as well as slotted and solid walls with viscous effects. This code was developed by modifying the outer boundary conditions of an existing aerodynamic wing-body-pod-pylon-winglet analysis code. The boundary conditions are presented in the form of equations which simulate the flow at the wall, as well as finite difference approximations to the equations. Comparisons are presented at transonic flow conditions between computational results and experimental data for a wing alone in a solid wall wind tunnel and wing-body configurations in both slotted and solid wind tunnels.

Functional dissociation of stimulus intensity encoding and predictive coding of pain in the insula

PubMed Central

Geuter, Stephan; Boll, Sabrina; Eippert, Falk; Büchel, Christian

2017-01-01

The computational principles by which the brain creates a painful experience from nociception are still unknown. Classic theories suggest that cortical regions either reflect stimulus intensity or additive effects of intensity and expectations, respectively. By contrast, predictive coding theories provide a unified framework explaining how perception is shaped by the integration of beliefs about the world with mismatches resulting from the comparison of these beliefs against sensory input. Using functional magnetic resonance imaging during a probabilistic heat pain paradigm, we investigated which computations underlie pain perception. Skin conductance, pupil dilation, and anterior insula responses to cued pain stimuli strictly followed the response patterns hypothesized by the predictive coding model, whereas posterior insula encoded stimulus intensity. This novel functional dissociation of pain processing within the insula together with previously observed alterations in chronic pain offer a novel interpretation of aberrant pain processing as disturbed weighting of predictions and prediction errors. DOI: http://dx.doi.org/10.7554/eLife.24770.001 PMID:28524817

Aircraft noise prediction

NASA Astrophysics Data System (ADS)

Filippone, Antonio

2014-07-01

This contribution addresses the state-of-the-art in the field of aircraft noise prediction, simulation and minimisation. The point of view taken in this context is that of comprehensive models that couple the various aircraft systems with the acoustic sources, the propagation and the flight trajectories. After an exhaustive review of the present predictive technologies in the relevant fields (airframe, propulsion, propagation, aircraft operations, trajectory optimisation), the paper addresses items for further research and development. Examples are shown for several airplanes, including the Airbus A319-100 (CFM engines), the Bombardier Dash8-Q400 (PW150 engines, Dowty R408 propellers) and the Boeing B737-800 (CFM engines). Predictions are done with the flight mechanics code FLIGHT. The transfer function between flight mechanics and the noise prediction is discussed in some details, along with the numerical procedures for validation and verification. Some code-to-code comparisons are shown. It is contended that the field of aircraft noise prediction has not yet reached a sufficient level of maturity. In particular, some parametric effects cannot be investigated, issues of accuracy are not currently addressed, and validation standards are still lacking.

Prediction of the explosion effect of aluminized explosives

NASA Astrophysics Data System (ADS)

Zhang, Qi; Xiang, Cong; Liang, HuiMin

2013-05-01

We present an approach to predict the explosion load for aluminized explosives using a numerical calculation. A code to calculate the species of detonation products of high energy ingredients and those of the secondary reaction of aluminum and the detonation products, velocity of detonation, pressure, temperature and JWL parameters of aluminized explosives has been developed in this study. Through numerical calculations carried out with this code, the predicted JWL parameters for aluminized explosives have been compared with those measured by the cylinder test. The predicted JWL parameters with this code agree with those measured by the cylinder test. Furthermore, the load of explosion for the aluminized explosive was calculated using the numerical simulation by using the JWL equation of state. The loads of explosion for the aluminized explosive obtained using the predicted JWL parameters have been compared with those using the measured JWL parameters. Both of them are almost the same. The numerical results using the predicted JWL parameters show that the explosion air shock wave is the strongest when the mass fraction of aluminum powder in the explosive mixtures is 30%. This result agrees with the empirical data.

Automated Concurrent Blackboard System Generation in C++

NASA Technical Reports Server (NTRS)

Kaplan, J. A.; McManus, J. W.; Bynum, W. L.

1999-01-01

In his 1992 Ph.D. thesis, "Design and Analysis Techniques for Concurrent Blackboard Systems", John McManus defined several performance metrics for concurrent blackboard systems and developed a suite of tools for creating and analyzing such systems. These tools allow a user to analyze a concurrent blackboard system design and predict the performance of the system before any code is written. The design can be modified until simulated performance is satisfactory. Then, the code generator can be invoked to generate automatically all of the code required for the concurrent blackboard system except for the code implementing the functionality of each knowledge source. We have completed the port of the source code generator and a simulator for a concurrent blackboard system. The source code generator generates the necessary C++ source code to implement the concurrent blackboard system using Parallel Virtual Machine (PVM) running on a heterogeneous network of UNIX(trademark) workstations. The concurrent blackboard simulator uses the blackboard specification file to predict the performance of the concurrent blackboard design. The only part of the source code for the concurrent blackboard system that the user must supply is the code implementing the functionality of the knowledge sources.

Integration of a supersonic unsteady aerodynamic code into the NASA FASTEX system

NASA Technical Reports Server (NTRS)

Appa, Kari; Smith, Michael J. C.

1987-01-01

A supersonic unsteady aerodynamic loads prediction method based on the constant pressure method was integrated into the NASA FASTEX system. The updated FASTEX code can be employed for aeroelastic analyses in subsonic and supersonic flow regimes. A brief description of the supersonic constant pressure panel method, as applied to lifting surfaces and body configurations, is followed by a documentation of updates required to incorporate this method in the FASTEX code. Test cases showing correlations of predicted pressure distributions, flutter solutions, and stability derivatives with available data are reported.

A Predictive Coding Account of Psychotic Symptoms in Autism Spectrum Disorder

ERIC Educational Resources Information Center

van Schalkwyk, Gerrit I.; Volkmar, Fred R.; Corlett, Philip R.

2017-01-01

The co-occurrence of psychotic and autism spectrum disorder (ASD) symptoms represents an important clinical challenge. Here we consider this problem in the context of a computational psychiatry approach that has been applied to both conditions--predictive coding. Some symptoms of schizophrenia have been explained in terms of a failure of top-down…

The Prediction of Performance in Navy Signalman Class "A" School. TAEG Report No. 90.

ERIC Educational Resources Information Center

Mew, Dorothy V.

A study designed to develop a selection model for the prediction of Signalman performance in sending and receiving Morse code and to evaluate training strategies was conducted with 180 Navy and Coast Guard enlisted men. Trainees were taught to send Morse code using innovative training materials (mnemonics and guided practice). High and average…

Three-dimensional water droplet trajectory code validation using an ECS inlet geometry

NASA Technical Reports Server (NTRS)

Breer, Marlin D.; Goodman, Mark P.

1993-01-01

A task was completed under NASA contract, the purpose of which was to validate a three-dimensional particle trajectory code with existing test data obtained from the Icing Research Tunnel at NASA-LeRC. The geometry analyzed was a flush-mounted environmental control system (ECS) inlet. Results of the study indicated good overall agreement between analytical predictions and wind tunnel test results at most flight conditions. Difficulties were encountered when predicting impingement characteristics of the droplets less than or equal to 13.5 microns in diameter. This difficulty was corrected to some degree by modifications to a module of the particle trajectory code; however, additional modifications will be required to accurately predict impingement characteristics of smaller droplets.

Comparison of FDNS liquid rocket engine plume computations with SPF/2

NASA Technical Reports Server (NTRS)

Kumar, G. N.; Griffith, D. O., II; Warsi, S. A.; Seaford, C. M.

1993-01-01

Prediction of a plume's shape and structure is essential to the evaluation of base region environments. The JANNAF standard plume flowfield analysis code SPF/2 predicts plumes well, but cannot analyze base regions. Full Navier-Stokes CFD codes can calculate both zones; however, before they can be used, they must be validated. The CFD code FDNS3D (Finite Difference Navier-Stokes Solver) was used to analyze the single plume of a Space Transportation Main Engine (STME) and comparisons were made with SPF/2 computations. Both frozen and finite rate chemistry models were employed as well as two turbulence models in SPF/2. The results indicate that FDNS3D plume computations agree well with SPF/2 predictions for liquid rocket engine plumes.

An evaluation of a computer code based on linear acoustic theory for predicting helicopter main rotor noise. [CH-53A and S-76 helicopters

NASA Technical Reports Server (NTRS)

Davis, S. J.; Egolf, T. A.

1980-01-01

Acoustic characteristics predicted using a recently developed computer code were correlated with measured acoustic data for two helicopter rotors. The analysis, is based on a solution of the Ffowcs-Williams-Hawkings (FW-H) equation and includes terms accounting for both the thickness and loading components of the rotational noise. Computations are carried out in the time domain and assume free field conditions. Results of the correlation show that the Farrassat/Nystrom analysis, when using predicted airload data as input, yields fair but encouraging correlation for the first 6 harmonics of blade passage. It also suggests that although the analysis represents a valuable first step towards developing a truly comprehensive helicopter rotor noise prediction capability, further work remains to be done identifying and incorporating additional noise mechanisms into the code.

A study on multiresolution lossless video coding using inter/intra frame adaptive prediction

NASA Astrophysics Data System (ADS)

Nakachi, Takayuki; Sawabe, Tomoko; Fujii, Tetsuro

2003-06-01

Lossless video coding is required in the fields of archiving and editing digital cinema or digital broadcasting contents. This paper combines a discrete wavelet transform and adaptive inter/intra-frame prediction in the wavelet transform domain to create multiresolution lossless video coding. The multiresolution structure offered by the wavelet transform facilitates interchange among several video source formats such as Super High Definition (SHD) images, HDTV, SDTV, and mobile applications. Adaptive inter/intra-frame prediction is an extension of JPEG-LS, a state-of-the-art lossless still image compression standard. Based on the image statistics of the wavelet transform domains in successive frames, inter/intra frame adaptive prediction is applied to the appropriate wavelet transform domain. This adaptation offers superior compression performance. This is achieved with low computational cost and no increase in additional information. Experiments on digital cinema test sequences confirm the effectiveness of the proposed algorithm.

Wake coupling to full potential rotor analysis code

NASA Technical Reports Server (NTRS)

Torres, Francisco J.; Chang, I-Chung; Oh, Byung K.

1990-01-01

The wake information from a helicopter forward flight code is coupled with two transonic potential rotor codes. The induced velocities for the near-, mid-, and far-wake geometries are extracted from a nonlinear rigid wake of a standard performance and analysis code. These, together with the corresponding inflow angles, computation points, and azimuth angles, are then incorporated into the transonic potential codes. The coupled codes can then provide an improved prediction of rotor blade loading at transonic speeds.

Chromosome preference of disease genes and vectorization for the prediction of non-coding disease genes.

PubMed

Peng, Hui; Lan, Chaowang; Liu, Yuansheng; Liu, Tao; Blumenstein, Michael; Li, Jinyan

2017-10-03

Disease-related protein-coding genes have been widely studied, but disease-related non-coding genes remain largely unknown. This work introduces a new vector to represent diseases, and applies the newly vectorized data for a positive-unlabeled learning algorithm to predict and rank disease-related long non-coding RNA (lncRNA) genes. This novel vector representation for diseases consists of two sub-vectors, one is composed of 45 elements, characterizing the information entropies of the disease genes distribution over 45 chromosome substructures. This idea is supported by our observation that some substructures (e.g., the chromosome 6 p-arm) are highly preferred by disease-related protein coding genes, while some (e.g., the 21 p-arm) are not favored at all. The second sub-vector is 30-dimensional, characterizing the distribution of disease gene enriched KEGG pathways in comparison with our manually created pathway groups. The second sub-vector complements with the first one to differentiate between various diseases. Our prediction method outperforms the state-of-the-art methods on benchmark datasets for prioritizing disease related lncRNA genes. The method also works well when only the sequence information of an lncRNA gene is known, or even when a given disease has no currently recognized long non-coding genes.

Chromosome preference of disease genes and vectorization for the prediction of non-coding disease genes

PubMed Central

Peng, Hui; Lan, Chaowang; Liu, Yuansheng; Liu, Tao; Blumenstein, Michael; Li, Jinyan

2017-01-01

Disease-related protein-coding genes have been widely studied, but disease-related non-coding genes remain largely unknown. This work introduces a new vector to represent diseases, and applies the newly vectorized data for a positive-unlabeled learning algorithm to predict and rank disease-related long non-coding RNA (lncRNA) genes. This novel vector representation for diseases consists of two sub-vectors, one is composed of 45 elements, characterizing the information entropies of the disease genes distribution over 45 chromosome substructures. This idea is supported by our observation that some substructures (e.g., the chromosome 6 p-arm) are highly preferred by disease-related protein coding genes, while some (e.g., the 21 p-arm) are not favored at all. The second sub-vector is 30-dimensional, characterizing the distribution of disease gene enriched KEGG pathways in comparison with our manually created pathway groups. The second sub-vector complements with the first one to differentiate between various diseases. Our prediction method outperforms the state-of-the-art methods on benchmark datasets for prioritizing disease related lncRNA genes. The method also works well when only the sequence information of an lncRNA gene is known, or even when a given disease has no currently recognized long non-coding genes. PMID:29108274

Edge-diffraction effects in RCS predictions and their importance in systems analysis

NASA Astrophysics Data System (ADS)

Friess, W. F.; Klement, D.; Ruppel, M.; Stein, Volker

1996-06-01

In developing RCS prediction codes a variety of physical effects such as the edge diffraction effect have to be considered with the consequence that the computer effort increases considerably. This fact limits the field of application of such codes, especially if the RCS data serve as input parameters for system simulators which very often need these data for a high number of observation angles and/or frequencies. Vice versa the issues of a system analysis can be used to estimate the relevance of physical effects under system viewpoints and to rank them according to their magnitude. This paper tries to evaluate the importance of RCS predictions containing an edge diffracted field for systems analysis. A double dihedral with a strong depolarizing behavior and a generic airplane design containing many arbitrarily oriented edges are used as test structures. Data of the scattered field are generated by the RCS computer code SIGMA with and without including edge diffraction effects. These data are submitted to the code DORA to determine radar range and radar detectibility and to a SAR simulator code to generate SAR imagery. In both cases special scenarios are assumed. The essential features of the computer codes in their current state are described, the results are presented and discussed under systems viewpoints.

DARTAB: a program to combine airborne radionuclide environmental exposure data with dosimetric and health effects data to generate tabulations of predicted health impacts

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

Begovich, C.L.; Eckerman, K.F.; Schlatter, E.C.

1981-08-01

The DARTAB computer code combines radionuclide environmental exposure data with dosimetric and health effects data to generate tabulations of the predicted impact of radioactive airborne effluents. DARTAB is independent of the environmental transport code used to generate the environmental exposure data and the codes used to produce the dosimetric and health effects data. Therefore human dose and risk calculations need not be added to every environmental transport code. Options are included in DARTAB to permit the user to request tabulations by various topics (e.g., cancer site, exposure pathway, etc.) to facilitate characterization of the human health impacts of the effluents.more » The DARTAB code was written at ORNL for the US Environmental Protection Agency, Office of Radiation Programs.« less

Do In Situ Observations Contain Signatures of Intermittent Fast Solar Wind Acceleration?

NASA Astrophysics Data System (ADS)

Matteini, L.; Horbury, T. S.; Stansby, D.

2017-12-01

Disentangling local plasma properties and Solar origin structures in in situ data is a crucial aspect for the understanding of solar wind acceleration and evolution. This is particularly challenging at 1 AU and beyond, where structures of various origin have had time to interact and merge, smoothing out their main characteristics. Observations of more pristine plasma closer to the Sun are therefore needed. In preparation of the forthcoming Solar Orbiter and Parker Solar Probe missions, Helios observations as close as to 0.3 AU - although old, not yet fully exploited - can be used to test our expectations and make new predictions. Recent observations (Matteini et al. 2014, 2015) have outlined the presence of intense (up to 1000km/s) and short-living velocity peaks that ubiquitously characterize the typical profile of the fast solar wind at 0.3 AU, suggesting that these features could be remnants of processes occurring in the Solar atmosphere and a signature of intermittent solar wind acceleration from coronal holes. We discuss results about statistics of these events, characterizing their physical properties and trying to link them with typical Solar temporal and spatial scales. Finally we also discuss how these velocity peaks will likely affect the future in situ exploration of the inner heliosphere by Solar Orbiter and the Parker Solar Probe.

Manual versus automated coding of free-text self-reported medication data in the 45 and Up Study: a validation study.

PubMed

Gnjidic, Danijela; Pearson, Sallie-Anne; Hilmer, Sarah N; Basilakis, Jim; Schaffer, Andrea L; Blyth, Fiona M; Banks, Emily

2015-03-30

Increasingly, automated methods are being used to code free-text medication data, but evidence on the validity of these methods is limited. To examine the accuracy of automated coding of previously keyed in free-text medication data compared with manual coding of original handwritten free-text responses (the 'gold standard'). A random sample of 500 participants (475 with and 25 without medication data in the free-text box) enrolled in the 45 and Up Study was selected. Manual coding involved medication experts keying in free-text responses and coding using Anatomical Therapeutic Chemical (ATC) codes (i.e. chemical substance 7-digit level; chemical subgroup 5-digit; pharmacological subgroup 4-digit; therapeutic subgroup 3-digit). Using keyed-in free-text responses entered by non-experts, the automated approach coded entries using the Australian Medicines Terminology database and assigned corresponding ATC codes. Based on manual coding, 1377 free-text entries were recorded and, of these, 1282 medications were coded to ATCs manually. The sensitivity of automated coding compared with manual coding was 79% (n = 1014) for entries coded at the exact ATC level, and 81.6% (n = 1046), 83.0% (n = 1064) and 83.8% (n = 1074) at the 5, 4 and 3-digit ATC levels, respectively. The sensitivity of automated coding for blank responses was 100% compared with manual coding. Sensitivity of automated coding was highest for prescription medications and lowest for vitamins and supplements, compared with the manual approach. Positive predictive values for automated coding were above 95% for 34 of the 38 individual prescription medications examined. Automated coding for free-text prescription medication data shows very high to excellent sensitivity and positive predictive values, indicating that automated methods can potentially be useful for large-scale, medication-related research.

Influence of geomagnetic activity and earth weather changes on heart rate and blood pressure in young and healthy population

NASA Astrophysics Data System (ADS)

Ozheredov, V. A.; Chibisov, S. M.; Blagonravov, M. L.; Khodorovich, N. A.; Demurov, E. A.; Goryachev, V. A.; Kharlitskaya, E. V.; Eremina, I. S.; Meladze, Z. A.

2017-05-01

There are many references in the literature related to connection between the space weather and the state of human organism. The search of external factors influence on humans is a multi-factor problem and it is well known that humans have a meteo-sensitivity. A direct problem of finding the earth weather conditions, under which the space weather manifests itself most strongly, is discussed in the present work for the first time in the helio-biology. From a formal point of view, this problem requires identification of subset (magnetobiotropic region) in three-dimensional earth's weather parameters such as pressure, temperature, and humidity, corresponding to the days when the human body is the most sensitive to changes in the geomagnetic field variations and when it reacts by statistically significant increase (or decrease) of a particular physiological parameter. This formulation defines the optimization of the problem, and the solution of the latter is not possible without the involvement of powerful metaheuristic methods of searching. Using the algorithm of differential evolution, we prove the existence of magnetobiotropic regions in the earth's weather parameters, which exhibit magneto-sensitivity of systolic, diastolic blood pressure, and heart rate of healthy young subjects for three weather areas (combinations of atmospheric temperature, pressure, and humidity). The maximum value of the correlation confidence for the measurements attributable to the days of the weather conditions that fall into each of three magnetobiotropic areas is an order of 0.006, that is almost 10 times less than the confidence, equal to 0.05, accepted in many helio-biological researches.