Post-Fisherian Experimentation: From Physical to Virtual

DOE PAGES

Jeff Wu, C. F.

2014-04-24

Fisher's pioneering work in design of experiments has inspired further work with broader applications, especially in industrial experimentation. Three topics in physical experiments are discussed: principles of effect hierarchy, sparsity, and heredity for factorial designs, a new method called CME for de-aliasing aliased effects, and robust parameter design. The recent emergence of virtual experiments on a computer is reviewed. Here, some major challenges in computer experiments, which must go beyond Fisherian principles, are outlined.

Dynamics and statics of nonaxisymmetric liquid bridges

NASA Technical Reports Server (NTRS)

Alexander, J. Iwan D.; Resnick, Andy; Zhang, Yiqiang; Fedoseyev, A.

1994-01-01

We finished the construction of the experimental apparatus and the design and testing of some of the visualization and data acquisition techniques. Experimental work focused on three areas: force measurements, loss of stability to nonaxisymmetric bridges, and vibration behavior. The experimental work is summarized in section 2. Selected results from our force measurement experiments are outlined in section 3. In addition we worked on the theory of the dynamic stability of axisymmetric bridges and undertook numerical simulation of the effects of inclined gravity vectors on the minimum volume stability limit for static bridges. The results and status of our theoretical work and numerical simulation are described in section 4. Papers published and in preparation, conference presentations, etc., are described in section 5. Work planned for the third year is discussed in section 6. References cited in the report are listed in section 7.

Proceedings of the Twentieth NASA Propagation Experimenters Meeting (NAPEX 20) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop

NASA Technical Reports Server (NTRS)

Golshan, Nasser (Editor)

1996-01-01

The NASA Propagation Experimenters (NAPEX) Meeting is convened each year to discuss studies supported by the NASA Propagation Program. Representatives from the satellite communications (satcom) industry, academia, and government who have an interest in space-ground radio wave propagation are invited to NAPEX meetings for discussions and exchange of information. The reports delivered at these meetings by program managers and investigators present recent activities and future plans. This forum provides an opportunity for peer discussion of work in progress, timely dissemination of propagation results, and close interaction with the satcom industry.

Centrifugal slurry pump wear and hydraulic studies. Phase II report. Experimental studies

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

Mistry, D.; Cooper, P.; Biswas, C.

1983-01-01

This report describes the work performed by Ingersoll-Rand Research, Inc., under Phase II, Experimental Studies for the contract entitled, Centrifugal Slurry Pump Wear and Hydraulic Studies. This work was carried out for the US Department of Energy under Contract No. DE-AC-82PC50035. The basic development approach pursued this phase is presented, followed by a discussion on wear relationships. The analysis, which resulted in the development of a mathematical wear model relating pump life to some of the key design and operating parameters, is presented. The results, observations, and conclusions of the experimental investigation on small scale pumps that led to themore » selected design features for the prototype pump are discussed. The material investigation was performed at IRRI, ORNL and Battelle. The rationale for selecting the materials for testing, the test methods and apparatus used, and the results obtained are presented followed by a discussion on materials for a prototype pump. In addition, the prototype pump test facility description, as well as the related design and equipment details, are presented. 20 references, 53 figures, 13 tables.« less

The use of plasma technology for the treatment of noxious waste

NASA Astrophysics Data System (ADS)

Wilman, Jonathan James

This thesis begins by describing the common types of air pollution and the main effects of these pollutants. Natural and man-made sources are discussed as well as the current types of technology used for reduction of common pollutants. The use of atmospheric pressure non-thermal plasma reactors for the control of pollutants is introduced at this stage. The second chapter describes the different types of atmospheric pressure non-thermal reactor designs and their modes of operation. The fundamental processes behind the production of plasmas are discussed and the chemistry of some simple discharges is also presented. The third chapter begins the experimental and modelling work done at Manchester on the destruction of volatile organic compounds (VOCs) using packed bed reactors and pulsed corona reactors. This chapter is concerned with the destruction of toluene and its behaviour as the oxygen content of the carrier gas, flowing through the reactor, is changed. Work using a pulsed corona reactor is also presented showing the destruction of toluene as a function of the applied specific energy. A model is constructed using mainly atmospheric reactions and the predictions are compared with experimental values. The fourth chapter discusses the destruction of dichloromethane (DCM) as a function of the oxygen content of the carrier gas. A model is constructed, again from mainly atmospheric reactions, and the predictions compared with the experimental data obtained. Methane is chosen as a molecule to study in the fifth chapter. A model is constructed and compared with experimental findings, showing that the chemistry of non-thermal plasmas can be effectively represented using neutral gas phase chemistry. Finally chapter six is concerned with the use of a large scale pulsed corona system for the reduction of NO[x] in industrial flue gas. This system has been tested on a modem incinerator, showing encouraging results. The workings of a modem incinerator are described together with those of the corona facility and any instruments used in these tests. Some experimental results are discussed. The aim of this chapter is to show that plasma reactors can be scaled up for industrial use. This section also discusses the difficulty of analysing and working with industrial gases and large scale apparatus as opposed to laboratory scale experiments.

Hamlet on the Macintosh: An Experimental Seminar That Worked.

ERIC Educational Resources Information Center

Strange, William C.

1987-01-01

Describes experimental college Shakespeare seminar that used Macintosh computers and software called ELIZA and ADVENTURE to develop character dialogs and adventure games based on Hamlet's characters and plots. Programming languages are examined, particularly their relationship to metaphor, and the use of computers in humanities is discussed. (LRW)

Adaptive Control of Four-Leg VSC Based DSTATCOM in Distribution System

NASA Astrophysics Data System (ADS)

Singh, Bhim; Arya, Sabha Raj

2014-01-01

This work discusses an experimental performance of a four-leg Distribution Static Compensator (DSTATCOM) using an adaptive filter based approach. It is used for estimation of reference supply currents through extracting the fundamental active power components of three-phase distorted load currents. This control algorithm is implemented on an assembled DSTATCOM for harmonics elimination, neutral current compensation and load balancing, under nonlinear loads. Experimental results are discussed, and it is noticed that DSTATCOM is effective solution to perform satisfactory performance under load dynamics.

Evaluating Computational Gene Ontology Annotations.

PubMed

Škunca, Nives; Roberts, Richard J; Steffen, Martin

2017-01-01

Two avenues to understanding gene function are complementary and often overlapping: experimental work and computational prediction. While experimental annotation generally produces high-quality annotations, it is low throughput. Conversely, computational annotations have broad coverage, but the quality of annotations may be variable, and therefore evaluating the quality of computational annotations is a critical concern.In this chapter, we provide an overview of strategies to evaluate the quality of computational annotations. First, we discuss why evaluating quality in this setting is not trivial. We highlight the various issues that threaten to bias the evaluation of computational annotations, most of which stem from the incompleteness of biological databases. Second, we discuss solutions that address these issues, for example, targeted selection of new experimental annotations and leveraging the existing experimental annotations.

Computer Simulation of Laboratory Experiments: An Unrealized Potential.

ERIC Educational Resources Information Center

Magin, D. J.; Reizes, J. A.

1990-01-01

Discussion of the use of computer simulation for laboratory experiments in undergraduate engineering education focuses on work at the University of New South Wales in the instructional design and software development of a package simulating a heat exchange device. The importance of integrating theory, design, and experimentation is also discussed.…

Effect of restriction of working memory on reported paranormal belief.

PubMed

Dudley, R T

1999-02-01

56 college students completed Tobacyk's 1988 Revised Paranormal Belief Scale and Watson, Clark, and Tellegen's 1988 Positive and Negative Affect Scale. Experimental group participants, but not control group participants, rehearsed a five-digit number while completing the Paranormal Belief Scale. Analysis showed higher reported paranormal belief for experimental group participants but no differences on the Positive and Negative Affect Scale. Results are discussed in terms of the effect of restriction in working memory on the critical evaluation of paranormal phenomena.

Proceedings of the Twenty-First NASA Propagation Experimenters Meeting (NAPEX XXI) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop

NASA Technical Reports Server (NTRS)

Golshan, Nasser (Editor)

1997-01-01

The NASA Propagation Experimenters (NAPEX) meeting is convened each year to discuss studies supported by the NASA Propagation Program. Representatives from the satellite communications industry, academia and government who have an interest in space-ground radio wave propagation are invited to NAPEX meetings for discussions and exchange of information. The reports delivered at this meeting by program managers and investigators present recent activities and future plans. This forum provides an opportunity for peer discussion of work in progress, timely dissemination of propagation results, and close interaction with the satellite communications industry.

At Odds: Reconciling Experimental and Theoretical Results in High School Physics

ERIC Educational Resources Information Center

Gates, Joshua

2009-01-01

For this experiment, students are divided into 2 groups and presented with a static equilibrium force-balance problem to solve. One group works entirely experimentally and the other group theoretically, using Newton's laws. The groups present their seemingly dissimilar results and must reconcile them through discussion. (Contains 3 figures.)

Novel into Film: An Experimental Course.

ERIC Educational Resources Information Center

Admussen, Richard L.; And Others

1978-01-01

A course studying narrative works from eight major French novelists, and the film adaptions of these works are described. Course discussions are directed toward a deeper understanding of the novel and a comparison of the structures, techniques, and limits of the two genres. Journal availability: Literature/Film Quarterly, Salisbury State College,…

Design and experimental investigation of an ejector in an air-conditioning and refrigeration system

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

AL-Khalidy, N.; Zayonia, A.

1995-12-31

This paper discusses the conservation of energy in a refrigerant ejector refrigerating machine using heat driven from the concentrator collectors. The working refrigerant was R-113. The design of an ejector operating in an air-conditioning and refrigerating system with a low thermal source (70 C to 100 C) is presented. The influence of three major parameters--boiler, condenser, and evaporator temperature--on ejector efficiency is discussed. Experimental results show that the condenser temperature is the major influence at a low evaporator temperature. The maximum ejector efficiency was 31%.

Flying qualities criteria for GA single pilot IFR operations

NASA Technical Reports Server (NTRS)

Bar-Gill, A.

1982-01-01

The flying qualities criteria in general aviation (GA) to decrease accidents are discussed. The following in-flight research is discussed: (1) identification of key aerodynamic configurations; (2) implementation of an in-flight simulator; (3) mission matrix design; (4) experimental systems; (5) data reduction; (6) optimal flight path reconstruction. Some of the accomplished work is reported: an integrated flight testing and flight path reconstruction methodology was developd, high accuracy in trajectory estimation was achieved with an experimental setup, and a part of the flight test series was flown.

Advanced Communications Technology Satellite (ACTS). Phase 1: Industrial/academic experimenters

NASA Technical Reports Server (NTRS)

Maisel, James E.; Nowlin, Robert W.

1992-01-01

This report presents the work done at Arizona State University under the ACTS Experimenters Program. The main thrust of the Program was to develop experiments to test, evaluate, and prove the commercial worthiness of the ACTS satellite which is scheduled for launch in 1993. To accomplish this goal, meetings were held with various governmental, industrial, and academic units to discuss the ACTS satellite and its technology and possible experiments that would generate industrial interest and support for ASU's efforts. Several local industries generated several experiments of their own. The investigators submitted several experiments of educational, medical, commercial, and technical value and interest. The disposition of these experimental proposals is discussed in this report.

Flow induction by pressure forces

NASA Technical Reports Server (NTRS)

Garris, C. A.; Toh, K. H.; Amin, S.

1992-01-01

A dual experimental/computational approach to the fluid mechanics of complex interactions that take place in a rotary-jet ejector is presented. The long-range goal is to perform both detailed flow mapping and finite element computational analysis. The described work represents an initial finding on the experimental mapping program. Test results on the hubless rotary-jet are discussed.

Towards adaptive, streaming analysis of x-ray tomography data

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

Thomas, Mathew; Kleese van Dam, Kerstin; Marshall, Matthew J.

2015-03-04

Temporal and spatial resolution of chemical imaging methodologies such as x-ray tomography are rapidly increasing, leading to more complex experimental procedures and fast growing data volumes. Automated analysis pipelines and big data analytics are becoming essential to effectively evaluate the results of such experiments. Offering those data techniques in an adaptive, streaming environment can further substantially improve the scientific discovery process, by enabling experimental control and steering based on the evaluation of emerging phenomena as they are observed by the experiment. Pacific Northwest National Laboratory (PNNL)’ Chemical Imaging Initiative (CII - http://imaging.pnnl.gov/ ) has worked since 2011 towards developing amore » framework that allows users to rapidly compose and customize high throughput experimental analysis pipelines for multiple instrument types. The framework, named ‘Rapid Experimental Analysis’ (REXAN) Framework [1], is based on the idea of reusable component libraries and utilizes the PNNL developed collaborative data management and analysis environment ‘Velo’, to provide a user friendly analysis and data management environment for experimental facilities. This article will, discuss the capabilities established for X-Ray tomography, discuss lessons learned, and provide an overview of our more recent work in the Analysis in Motion Initiative (AIM - http://aim.pnnl.gov/ ) at PNNL to provide REXAN capabilities in a streaming environment.« less

Tribute to the contribution of Gerard Lallenment to structural dynamics

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

Los Alamos National Laboratory

The Society for Experimental Mechanics and the International Modal Analysis Conference recognize the remarkable contribution to experimental mechanics, mechanical engineering and structural dynamics of Professor Gerard Lallement, from the University of Franche-Comte, France. A special session is organized during the IMAC-XX to outline the many achievements of Gerard Lallement in the fields of modal analysis, structural system identification, the theory and practice of structural modification, component mode synthesis and finite element model updating. The purpose of this publication is not to provide an exhaustive account of Gerard Lallement's contribution to structural dynamics. Numerous references are provided that should help themore » interested reader learn more about the many aspects of his work. Instead, the significance of this work is illustrated by discussing the role of structural dynamics in industrial applications and its future challenges. The technical aspects of Gerard Lallement's work are illustrated with a discussion of structural modification, modeling error localization and model updating.« less

Flora of the Fraser Experimental Forest, Colorado. Forest Service general technical report (Final)

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

Popovich, S.J.; Shepperd, W.D.; Reichert, D.W.

1993-08-01

The report lists 441 vascular plant taxa in 228 genera and 63 families encountered on the 9,300-ha Fraser Experimental Forest in central Colorado. Synonyms appearing in previous publications and other works pertaining to the Fraser Experimental Forest, as well as appropriate Colorado floras and less-technical field guides, are included. Plant communities and habitats are discussed, and a list of 54 lichens is also presented. A glossary of related terms is included.

A hierarchical structure for automatic meshing and adaptive FEM analysis

NASA Technical Reports Server (NTRS)

Kela, Ajay; Saxena, Mukul; Perucchio, Renato

1987-01-01

A new algorithm for generating automatically, from solid models of mechanical parts, finite element meshes that are organized as spatially addressable quaternary trees (for 2-D work) or octal trees (for 3-D work) is discussed. Because such meshes are inherently hierarchical as well as spatially addressable, they permit efficient substructuring techniques to be used for both global analysis and incremental remeshing and reanalysis. The global and incremental techniques are summarized and some results from an experimental closed loop 2-D system in which meshing, analysis, error evaluation, and remeshing and reanalysis are done automatically and adaptively are presented. The implementation of 3-D work is briefly discussed.

A survey of the alpha-nucleon interaction

NASA Astrophysics Data System (ADS)

Ali, S.; Ahmad, A. A. Z.; Ferdous, N.

1985-10-01

This paper gives a survey of the alpha-nucleon interaction and then describes experimental work on angular distributions of differential scattering cross sections and polarizations in proton-alpha and neutron-alpha scattering. The phenomenological approach, which includes the study of both local and nonlocal potentials reproducing the experimental alpha-nucleon scattering data, is discussed. Basic studies of the alpha-nucleon interaction attempting to build an interaction between an alpha particle and a nucleon from first principles are then described. The authors then present a critical discussion of the results with some concluding remarks suggesting the direction for further investigation.

HOLONET: a network for training holography

NASA Astrophysics Data System (ADS)

Pombo, Pedro; Santos, Emanuel

2014-07-01

Holography is an optics technique based on wave physics and lasers with several applications at our day life. The production of holograms involves experimental work based on hands-on activities and creativity. All these elements can contribute to the promotion of experimental teaching of optics and training on holography. The hologram itself acting as a final result from a long process of research and study can enable the engagement of high school students on physics and promote the stimulus on optics learning. Taking these assumptions into account a network of schools working on holography was built involving thirty schools from all country. Holography systems were developed and several hands-on activities were constructed. During last sixteen years students are working on laser optics and holography producing different kinds of holograms. This study presents all holography labs implemented at schools and it will analyzed the holography systems and materials developed for students. Training strategy will be discussed and holograms obtained by students will be presented. Results obtained show us that holography can be implemented as a strategy for promoting the learning of optics and it is a particular way to involve students on experimental work and lab research. Results obtained during this study will be presented in detail and analyzed with focus on students performance. Educational results, teachers training, prizes and other positive outcomes will be discussed and compared.

NOEC and LOEC as merely concessive expedients: two unambiguous alternatives and some criteria to maximize the efficiency of dose-response experimental designs.

PubMed

Murado, M A; Prieto, M A

2013-09-01

NOEC and LOEC (no and lowest observed effect concentrations, respectively) are toxicological concepts derived from analysis of variance (ANOVA), a not very sensitive method that produces ambiguous results and does not provide confidence intervals (CI) of its estimates. For a long time, despite the abundant criticism that such concepts have raised, the field of the ecotoxicology is reticent to abandon them (two possible reasons will be discussed), adducing the difficulty of clear alternatives. However, this work proves that a debugged dose-response (DR) modeling, through explicit algebraic equations, enables two simple options to accurately calculate the CI of substantially lower doses than NOEC. Both ANOVA and DR analyses are affected by the experimental error, response profile, number of observations and experimental design. The study of these effects--analytically complex and experimentally unfeasible--was carried out using systematic simulations with realistic data, including different error levels. Results revealed the weakness of NOEC and LOEC notions, confirmed the feasibility of the proposed alternatives and allowed to discuss the--often violated--conditions that minimize the CI of the parametric estimates from DR assays. In addition, a table was developed providing the experimental design that minimizes the parametric CI for a given set of working conditions. This makes possible to reduce the experimental effort and to avoid the inconclusive results that are frequently obtained from intuitive experimental plans. Copyright © 2013 Elsevier B.V. All rights reserved.

Transplantation of the heart: An overview of 40 years' clinical and research experience at Groote Schuur Hospital and the University of Cape Town: Part II. Laboratory research experience.

PubMed

Hassoulas, J

2012-03-29

Extensive experimental research on various aspects of heart transplantation was undertaken during the first 2 decades. An overview of this work is presented, and some still unpublished work has been included. Experimental laboratory investigation was an integral activity of the cardiac transplantation programme at the University of Cape Town over these years, and has remained so ever since. These studies provided invaluable fundamental information upon which future clinical work was based. It is therefore necessary to briefly mention and discuss this information, most of which has been published in detail by the various investigators concerned.

Experimental research on electric propulsion. Note 5: Experimental study of a magnetic field stabilized arc-jet

NASA Technical Reports Server (NTRS)

Robotti, A. C.; Oggero, M.

1984-01-01

The possibility of using an electric arc under the influence of a magnetic field in ambient air to transform the heat energy of the working fluid arc into the kinetic energy of the jet was investigated. A convergent-divergent type nozzle was used. Variation of specific thrust and chamber pressure are discussed. Nitrogen was the propellant used.

Irradiation Design for an Experimental Murine Model

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

Ballesteros-Zebadua, P.; Moreno-Jimenez, S.; Suarez-Campos, J. E.

2010-12-07

In radiotherapy and stereotactic radiosurgery, small animal experimental models are frequently used, since there are still a lot of unsolved questions about the biological and biochemical effects of ionizing radiation. This work presents a method for small-animal brain radiotherapy compatible with a dedicated 6MV Linac. This rodent model is focused on the research of the inflammatory effects produced by ionizing radiation in the brain. In this work comparisons between Pencil Beam and Monte Carlo techniques, were used in order to evaluate accuracy of the calculated dose using a commercial planning system. Challenges in this murine model are discussed.

Experimental Investigation and Demonstration of Rotary-Wing Technologies for Flight in the Atmosphere of Mars

NASA Technical Reports Server (NTRS)

Young, L. A.; Derby, M. R.; Demblewski, R.; Navarrete, J.

2002-01-01

This paper details ongoing work at NASA Ames Research Center as to experimental investigations and demonstrations related to rotary-wing technologies that might be applied to flight in the atmosphere of Mars. Such Mars rotorcraft would provide a 'three-dimensional mobility' to the exploration of the Red Planet. Preliminary results from isolated rotor testing in Mars-representative atmospheric densities, as well as progress towards coaxial test stand development are discussed. Additionally, work towards the development and use of surrogate flight vehicles -- in the terrestrial environment -- to demonstrate key technologies is also summarized.

A Most Rare Vision: Improvisations on "A Midsummer Night's Dream."

ERIC Educational Resources Information Center

Hakaim, Charles J., Jr.

1993-01-01

Describes one teacher's methods for introducing to secondary English students the concepts of improvisation, experimentation, and innovation. Discusses numerous techniques for fostering such skills when working with William Shakespeare's "A Midsummer Night's Dream." (HB)

Characterization of study focus of the Brazilian academic-scientific production about experimentation in Physics Teaching

NASA Astrophysics Data System (ADS)

Wesendonk, F. S.; Terrazzan, E. A.

2016-12-01

In this article, we presented a characterization of the recent academic and scientific literature on experiments in Physics Education in terms of focus and research intentions and results built through these investigations. For this, we used as a source of information 10 national Academic and Scientific Journals available on websites. By consulting these journals, we identified that 147 papers published from 2009 to 2013 had as their main focus the experimental research. We classified the Works in categories established a priori and subcategories established a posteriori. At the end, we found out that few articles deal with this issue (9%). Moreover, in most productions there is a superficial discussion of theoretical studies on the use of experimentation in teaching. This makes the contribution of these productions for the development of conceptual discussions about the potential and limited use of experimentation in Physics Education to be relatively small.

THERMODYNAMICS OF FE-CU ALLOYS AS DESCRIBED BY A CLASSIC POTENTIALS

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

Caro, A; Caro, M; Lopasso, E M

2005-04-14

The Fe-Cu system is of relevance to the nuclear industry because of the deleterious consequences of Cu precipitates in the mechanical properties of Fe. Several sets of classical potentials are used in molecular dynamics simulations studies of this system, in particular that proposed by Ludwig et al. (Modelling Simul. Mater. Sci. Eng. 6, 19 (1998)). In this work we extract thermodynamic information from this interatomic potentials. We obtain equilibrium phase diagram and find a reasonable agreement with the experimental phases in the regions of relevance to radiation damage studies. We compare the results with the predicted phase diagram based onmore » other potential, as calculated in previous work. We discuss the disagreements found between the phase diagram calculated here and experimental results, focusing on the pure components and discuss the applicability of these potentials; finally we suggest an approach to improve existing potentials for this system.« less

Can the experimental evolution programme help us elucidate the genetic basis of adaptation in nature?

PubMed

Bailey, Susan F; Bataillon, Thomas

2016-01-01

There have been a variety of approaches taken to try to characterize and identify the genetic basis of adaptation in nature, spanning theoretical models, experimental evolution studies and direct tests of natural populations. Theoretical models can provide formalized and detailed hypotheses regarding evolutionary processes and patterns, from which experimental evolution studies can then provide important proofs of concepts and characterize what is biologically reasonable. Genetic and genomic data from natural populations then allow for the identification of the particular factors that have and continue to play an important role in shaping adaptive evolution in the natural world. Further to this, experimental evolution studies allow for tests of theories that may be difficult or impossible to test in natural populations for logistical and methodological reasons and can even generate new insights, suggesting further refinement of existing theories. However, as experimental evolution studies often take place in a very particular set of controlled conditions--that is simple environments, a small range of usually asexual species, relatively short timescales--the question remains as to how applicable these experimental results are to natural populations. In this review, we discuss important insights coming from experimental evolution, focusing on four key topics tied to the evolutionary genetics of adaptation, and within those topics, we discuss the extent to which the experimental work compliments and informs natural population studies. We finish by making suggestions for future work in particular a need for natural population genomic time series data, as well as the necessity for studies that combine both experimental evolution and natural population approaches. © 2015 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

Work reservoirs in thermodynamics

NASA Astrophysics Data System (ADS)

Anacleto, Joaquim

2010-05-01

We stress the usefulness of the work reservoir in the formalism of thermodynamics, in particular in the context of the first law. To elucidate its usefulness, the formalism is then applied to the Joule expansion and other peculiar and instructive experimental situations, clarifying the concepts of configuration and dissipative work. The ideas and discussions presented in this study are primarily intended for undergraduate students, but they might also be useful to graduate students, researchers and teachers.

The Introduction of High-Throughput Experimentation Methods for Suzuki-Miyaura Coupling Reactions in University Education

ERIC Educational Resources Information Center

Hoogenboom, Richard; Meier, Michael A. R.; Schubert, Ulrich S.

2005-01-01

A laboratory project permits for the discussion of the reaction mechanism of the Suzuki-Miyaura coupling reaction. The practical part of the project makes the students familiar with working under inert atmosphere but if the appropriate equipment for working under inert atmosphere is not available in a laboratory, novel catalysts that do not…

Accurate Molecular Dimensions from Stearic Acid Monolayers.

ERIC Educational Resources Information Center

Lane, Charles A.; And Others

1984-01-01

Discusses modifications in the fatty acid monolayer experiment to reduce the inaccurate moleculary data students usually obtain. Copies of the experimental procedure used and a Pascal computer program to work up the data are available from the authors. (JN)

Wearable Learning Tools.

ERIC Educational Resources Information Center

Bowskill, Jerry; Dyer, Nick

1999-01-01

Describes wearable computers, or information and communication technology devices that are designed to be mobile. Discusses how such technologies can enhance computer-mediated communications, focusing on collaborative working for learning. Describes an experimental system, MetaPark, which explores communications, data retrieval and recording, and…

Discussion: ''toughness variations during the tempering of a plain carbon martensitic steel'' by J. E. King, R. F. Smith and J. F. Knott. Retained austenite and transgranular tempered martensite embrittlement

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

Rao, B.V.N.; Thomas, G.

Discussion is presented to substantiate, clarify and reinterpret some of the results of the above authors for the existence and origin of tempered martensite embrittlement (TME) in relation to retained austenite, with reference to the experimental steels worked at LBL for the past several years.

High efficiency silicon solar cell review

NASA Technical Reports Server (NTRS)

Godlewski, M. P. (Editor)

1975-01-01

An overview is presented of the current research and development efforts to improve the performance of the silicon solar cell. The 24 papers presented reviewed experimental and analytic modeling work which emphasizes the improvment of conversion efficiency and the reduction of manufacturing costs. A summary is given of the round-table discussion, in which the near- and far-term directions of future efficiency improvements were discussed.

Studies of Premixed Laminar and Turbulent Flames at Microgravity

NASA Technical Reports Server (NTRS)

Ronney, Paul D.

1993-01-01

The work of the Principal Investigator (PI) has encompassed four topics related to the experimental and theoretical study of combustion limits in premixed flames at microgravity, as discussed in the following sections. These topics include: (1) radiation effects on premixed gas flames; (2) flame structure and stability at low Lewis number; (3) flame propagation and extinction is cylindrical tubes; and (4) experimental simulation of combustion processes using autocatalytic chemical reactions.

Research and training activities of the Joint Institute for Aeronautics and Acoustics

NASA Technical Reports Server (NTRS)

Roberts, L.

1993-01-01

During the period October 1992 to September 1993 progress was made on each of the following tasks: (1) experimental studies of free shear flows; (2) analysis of conical flow; (3) experimental and theoretical studies of vortex flows; and (4) aircraft attitude control using active flow control devices. The details of this work was discussed with the technical and management staff at Ames Research Center.

Electrocaloric Refrigeration for Superconductors

DTIC Science & Technology

1977-02-01

Dielectric properties 40 3.3.2. Relation to capacitance thermometer manufacturing . . 42 3.4. SrTiO, Glass-Ceramic Multilayer Samples 42 3.4.1...Experimental Methods 66 3.6.1. Dielectric properties 66 3.6.2. Thermodynamic properties 7 0 3.6.3. Thermal conductivity. .... 80 3.7...Discussion of Experimental Results 143 3.8.1. Dielectric Troperties 143 3.8.2. Thermal Properties 150 3.8.3. Recommendations for further work

Supersonic Combustion Research at NASA

NASA Technical Reports Server (NTRS)

Drummond, J. P.; Danehy, Paul M.; Gaffney, Richard L., Jr.; Tedder, Sarah A.; Cutler, Andrew D.; Bivolaru, Daniel

2007-01-01

This paper discusses the progress of work to model high-speed supersonic reacting flow. The purpose of the work is to improve the state of the art of CFD capabilities for predicting the flow in high-speed propulsion systems, particularly combustor flowpaths. The program has several components including the development of advanced algorithms and models for simulating engine flowpaths as well as a fundamental experimental and diagnostic development effort to support the formulation and validation of the mathematical models. The paper will provide details of current work on experiments that will provide data for the modeling efforts along with the associated nonintrusive diagnostics used to collect the data from the experimental flowfield. Simulation of a recent experiment to partially validate the accuracy of a combustion code is also described.

Positron scattering from molecular hydrogen

NASA Astrophysics Data System (ADS)

Machacek, J. R.; Anderson, E. K.; Makochekanwa, C.; Buckman, S. J.; Sullivan, J. P.

2013-10-01

We present results for total and partial cross sections for positron scattering from H2. The total scattering and positronium formation cross sections are reported between 0.5 and 200 eV. Total quasielastic and inelastic scattering cross sections are reported for energies between the positronium formation threshold and 50 eV, with quasielastic differential scattering cross sections reported at 1, 3, 5, 7, and 10 eV. Our results are compared with previous work, both experimental and theoretical, with particular attention paid to the region below the positronium formation threshold, where there are apparent discrepancies in previous work. A discussion of possible reasons for discrepancies between this and previous work is presented, including a focus on known systematic effects in the experimental results.

Engineering science research issues in high power density transmission dynamics for aerospace applications. [rotorcraft geared rotors

NASA Technical Reports Server (NTRS)

Singh, Rajendra; Houser, Donald R.

1993-01-01

This paper discusses analytical and experimental approaches that will be needed to understand dynamic, vibro-acoustic and design characteristics of high power density rotorcraft transmissions. Complexities associated with mathematical modeling of such systems will be discussed. An overview of research work planned during the next several years will be presented, with emphasis on engineering science issues such as gear contact mechanics, multi-mesh drive dynamics, parameter uncertainties, vibration transmission through bearings, and vibro-acoustic characteristics of geared rotor systems and housing-mount structures. A few examples of work in progress are cited.

Quantitative surface topography determination by Nomarski reflection microscopy. 2: Microscope modification, calibration, and planar sample experiments

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

Hartman, J.S.; Gordon, R.L.; Lessor, D.L.

1980-09-01

The application of reflective Nomarski differential interference contrast microscopy for the determination of quantitative sample topography data is presented. The discussion includes a review of key theoretical results presented previously plus the experimental implementation of the concepts using a commercial Momarski microscope. The experimental work included the modification and characterization of a commercial microscope to allow its use for obtaining quantitative sample topography data. System usage for the measurement of slopes on flat planar samples is also discussed. The discussion has been designed to provide the theoretical basis, a physical insight, and a cookbook procedure for implementation to allow thesemore » results to be of value to both those interested in the microscope theory and its practical usage in the metallography laboratory.« less

Church acoustics: A state-of-the-art review after several decades of research

NASA Astrophysics Data System (ADS)

Girón, Sara; Álvarez-Morales, Lidia; Zamarreño, Teófilo

2017-12-01

This work describes and analyses the principal contributions to the acoustics of occidental Christian churches from the second half of the last century to the present day, mainly in ancient historical churches. After more than six decades of research, it seems appropriate to summarise the major pieces of work in this field, and, to this end, this paper aims to provide an up-to-date document of all the most relevant studies which describe the exhaustive investigations of acoustic characterisation in time-consuming experimental campaigns carried out by several groups of researchers in various European countries. The article presents, for the research into church acoustics developed in each country, the experimental procedures, the results, discussions, the theoretical interpretations of the sound propagation in these spaces, the subjective aspects in the listening experience, and the method of implementation of computer simulation techniques and their applications in these complex enclosures. Other contributions from Asian and American continents are also included. Findings and advances in each of these areas as well as perspectives on their future challenges are summarized and discussed in this work.

Arguments, contradictions, resistances, and conceptual change in students' understanding of atomic structure

NASA Astrophysics Data System (ADS)

Niaz, Mansoor; Aguilera, Damarys; Maza, Arelys; Liendo, Gustavo

2002-07-01

Most general chemistry courses and textbooks emphasize experimental details and lack a history and philosophy of science perspective. The objective of this study is to facilitate freshman general chemistry students' understanding of atomic structure based on the work of Thomson, Rutherford, and Bohr. It is hypothesized that classroom discussions based on arguments/counterarguments of the heuristic principles, on which these scientists based their atomic models, can facilitate students' conceptual understanding. This study is based on 160 freshman students enrolled in six sections of General Chemistry I (three sections formed part of the experimental group). All three models (Thomson, Rutherford, and Bohr) were presented to the experimental and control group students in the traditional manner, as found in most textbooks. After this, the three sections of the experimental group participated in the discussion of six items with alternative responses. Students were first asked to select a response and then participate in classroom discussions leading to arguments in favor or against the selected response and finally select a new response. Three weeks after having discussed the six items, both the experimental and control groups presented a monthly exam (based on the three models) and after another 3 weeks a semester exam. Results obtained show that given the opportunity to argue and discuss, students' understanding can go beyond the simple regurgitation of experimental details. Performance of the experimental group showed contradictions, resistances, and progressive conceptual change with considerable and consistent improvement in the last item. It is concluded that if we want our students to understand scientific progress and practice, then it is important that we include the experimental details not as a rhetoric of conclusions (Schwab, 1962, The teaching of science as enquiry, Cambridge, MA, Harward University Press; Schwab, 1974, Conflicting conceptions of curriculum, Berkeley, CA, McCutchan) but as heuristic principles (Lakatos, 1970, Criticism and the growth of knowledge, Cambridge, UK, Cambridge University Press, pp. 91-195), which were based on arguments, controversies, and interpretations of the scientists.

TRIANGLE-SHAPED DC CORONA DISCHARGE DEVICE FOR MOLECULAR DECOMPOSITION

EPA Science Inventory

The paper discusses the evaluation of electrostatic DC corona discharge devices for the application of molecular decomposition. A point-to-plane geometry corona device with a rectangular cross section demonstrated low decomposition efficiencies in earlier experimental work. The n...

Design and experimental investigations on a small scale traveling wave thermoacoustic engine

NASA Astrophysics Data System (ADS)

Chen, M.; Ju, Y. L.

2013-02-01

A small scale traveling wave or Stirling thermoacoustic engine with a resonator of only 1 m length was designed, constructed and tested by using nitrogen as working gas. The small heat engine achieved a steady working frequency of 45 Hz. The pressure ratio reached 1.189, with an average charge pressure of 0.53 MPa and a heating power of 1.14 kW. The temperature and the pressure characteristics during the onset and damping processes were also observed and discussed. The experimental results demonstrated that the small engine possessed the potential to drive a Stirling-type pulse tube cryocooler.

Recombination of cluster ions

NASA Technical Reports Server (NTRS)

Johnsen, Rainer

1993-01-01

Some of our recent work on molecular band emissions from recombination of molecular dimer ions (N4(+) and CO(+) CO) is discussed. Much of the experimental work was done by Y. S. Cao; the results on N4(+) recombination have been published. A brief progress report is given on our ongoing measurements of neutral products of recombination using the flowing-afterglow Langmuir-probe technique in conjunction with laser-induced fluorescence.

Identification and robust control of an experimental servo motor.

PubMed

Adam, E J; Guestrin, E D

2002-04-01

In this work, the design of a robust controller for an experimental laboratory-scale position control system based on a dc motor drive as well as the corresponding identification and robust stability analysis are presented. In order to carry out the robust design procedure, first, a classic closed-loop identification technique is applied and then, the parametrization by internal model control is used. The model uncertainty is evaluated under both parametric and global representation. For the latter case, an interesting discussion about the conservativeness of this description is presented by means of a comparison between the uncertainty disk and the critical perturbation radius approaches. Finally, conclusions about the performance of the experimental system with the robust controller are discussed using comparative graphics of the controlled variable and the Nyquist stability margin as a robustness measurement.

Elastic Instability of Members Having Sections Common in Aircraft Construction

NASA Technical Reports Server (NTRS)

Trayer, George W; March, H W

1932-01-01

Two fundamental problems of elastic stability are discussed in this report. In part one formulas are given for calculating the critical stress at which a thin, outstanding flange of a compression member will either wrinkle into several waves or form into a single half wave and twist the member about its longitudinal axis. A mathematical study of the problem, which together with experimental work has led to these formulas, is given in an appendix. Results of test substantiating the recommended formulas are also presented. In part two the lateral buckling of beams is discussed. The results of a number of mathematical studies of this phenomenon have been published prior to this writing, but very little experimentally determined information relating to the problem has been available heretofore. Experimental verification of the mathematical deductions is supplied.

Traveling Magnetic Field Applications for Materials Processing in Space

NASA Technical Reports Server (NTRS)

Grugel, R. N.; Mazuruk, K.; Curreri, Peter A. (Technical Monitor)

2001-01-01

Including the capability to induce a controlled fluid flow in the melt can significantly enrich research on solidification phenomena in a microgravity environment. The traveling magnetic field (TMF) is a promising technique to achieve this goal and is the aim of our ground-based project. In this presentation we will discuss new theoretical as well as experimental results recently obtained by our group. In particular, we experimentally demonstrated efficient mixing of metal alloys in long tubes subjected to TMF during processing. Application of this technique can provide an elegant solution to ensure melt homogenization prior to solidification in a microgravity environment where natural convection is generally absent. Results of our experimental work of applying the TMF technique to alloy melts will be presented. Possible applications of TMF on board the International Space Station will also be discussed.

Structural dynamic and aeroelastic considerations for hypersonic vehicles

NASA Technical Reports Server (NTRS)

Cazier, F. W., Jr.; Doggett, Robert V., Jr.; Ricketts, Rodney H.

1991-01-01

The specific geometrical, structural, and operational environment characteristics of hypersonic vehicles are discussed with particular reference to aerospace plane type configurations. A discussion of the structural dynamic and aeroelastic phenomena that must be addressed for this class of vehicles is presented. These phenomena are in the aeroservothermoelasticity technical area. Some illustrative examples of recent experimental and analytical work are given. Some examples of current research are pointed out.

Sebastien Philippe Discusses the Zero-Knowledge Protocol

ScienceCinema

Philippe, Sebastien

2018-06-12

A system that can compare physical objects while potentially protecting sensitive information about the objects themselves has been demonstrated experimentally at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL). This work, by researchers at Princeton University and PPPL, marks an initial confirmation of the application of a powerful cryptographic technique in the physical world. Graduate student Sébastien Philippe discusses the experiment.

Evaluation of experimental parameters for growth of homogeneous solid solutions

NASA Astrophysics Data System (ADS)

Scheel, Hans J.; Swendsen, Robert H.

2001-12-01

In this paper, we discuss the experimental conditions required to grow large two-component crystals from homogeneous solid solutions. Building on the work of Burton, Prim, and Slichter and that of Van Erk, we are able to establish that the concentration fluctuations for diffusion-limited growth are rather insensitive to hydrodynamic fluctuations. This enables a crystal grower to take advantage of forced convection to optimize growth rates without aggravating the striation problem.

A comparison of experimental and theoretical results for rotordynamic coefficients of four annular gas seals

NASA Technical Reports Server (NTRS)

Childs, D. W.; Nelson, C. C.; Elrod, D.; Nicks, C.

1985-01-01

The test facility and initial test program developed to experimentally measure the fluid forces induced by annular gas seals is described. A comparison of theoretically predicted and experimentally obtained data for smooth and honeycomb seals is provided. And a comparison of experimental data from the tests of three smooth-rotor/smooth-stator seals is provided. The leakage of the working fluid through the seal, the pressure gradient along the seal length, entrance pressure-loss data, and rotordynamic coefficients provide a basis for comparison. A short discussion on seal theory is included, and various rotordynamic coefficient identification schemes are described.

July 1999 working group meeting on heavy vehicle aerodynamic drag: presentations and summary of comments and conclusions

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

Brady, M; Browand, F; Flowers, D

A Working Group Meeting on Heavy Vehicle Aerodynamic Drag was held at University of Southern California, Los Angeles, California on July 30, 1999. The purpose of the meeting was to present technical details on the experimental and computational plans and approaches and provide an update on progress in obtaining experimental results, model developments, and simulations. The focus of the meeting was a review of University of Southern California's (USC) experimental plans and results and the computational results from Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories (SNL) for the integrated tractor-trailer benchmark geometry called the Sandia Model. Much ofmore » the meeting discussion involved the NASA Ames 7 ft x 10 ft wind tunnel tests and the need for documentation of the results. The present and projected budget and funding situation was also discussed. Presentations were given by representatives from the Department of Energy (DOE) Office of Transportation Technology Office of Heavy Vehicle Technology (OHVT), LLNL, SNL, USC, and California Institute of Technology (Caltech). This report contains the technical presentations (viewgraphs) delivered at the Meeting, briefly summarizes the comments and conclusions, and outlines the future action items.« less

MICRO- AND NANOSCALE MEASUREMENT METHODS FOR PHASE CHANGE HEAT TRANSFER ON PLANAR AND STRUCTURED SURFACES

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

Buongiorno, J; Cahill, DG; Hidrovo, CH

2014-07-23

In this opinion piece, we discuss recent advances in experimental methods for characterizing phase change heat transfer. We begin with a survey of techniques for high-resolution measurements of temperature and heat flux at the solid surface and in the working fluid. Next, we focus on diagnostic tools for boiling heat transfer and describe techniques for visualizing the temperature and velocity fields, as well as measurements at the single bubble level. Finally, we discuss techniques to probe the kinetics of vapor formation within a few molecular layers of the interface. We conclude with our outlook for future progress in experimental methodsmore » for phase change heat transfer.« less

Gear and Transmission Research at NASA Lewis Research Center

NASA Technical Reports Server (NTRS)

Townsend, Dennis P.

1997-01-01

This paper is a review of some of the research work of the NASA Lewis Research Center Mechanical Components Branch. It includes a brief review of the NASA Lewis Research Center and the Mechanical Components Branch. The research topics discussed are crack propagation of gear teeth, gear noise of spiral bevel and other gears, design optimization methods, methods we have investigated for transmission diagnostics, the analytical and experimental study of gear thermal conditions, the analytical and experimental study of split torque systems, the evaluation of several new advanced gear steels and transmission lubricants and the evaluation of various aircraft transmissions. The area of research needs for gearing and transmissions is also discussed.

Modeling Combustion in Supersonic Flows

NASA Technical Reports Server (NTRS)

Drummond, J. Philip; Danehy, Paul M.; Bivolaru, Daniel; Gaffney, Richard L.; Tedder, Sarah A.; Cutler, Andrew D.

2007-01-01

This paper discusses the progress of work to model high-speed supersonic reacting flow. The purpose of the work is to improve the state of the art of CFD capabilities for predicting the flow in high-speed propulsion systems, particularly combustor flow-paths. The program has several components including the development of advanced algorithms and models for simulating engine flowpaths as well as a fundamental experimental and diagnostic development effort to support the formulation and validation of the mathematical models. The paper will provide details of current work on experiments that will provide data for the modeling efforts along with with the associated nonintrusive diagnostics used to collect the data from the experimental flowfield. Simulation of a recent experiment to partially validate the accuracy of a combustion code is also described.

Materials Research Conducted Aboard the International Space Station: Facilities Overview, Operational Procedures, and Experimental Outcomes

NASA Technical Reports Server (NTRS)

Grugel, Richard N.; Luz, Paul; Smith, Guy; Spivey, Reggie; Jeter, Linda; Gillies, Donald; Hua, Fay; Anikumar, A. V.

2007-01-01

The Microgravity Science Glovebox (MSG) and Maintenance Work Area (MWA) are facilities aboard the International Space Station (ISS) that were used to successfully conduct experiments in support of, respectively, the Pore Formation and Mobility Investigation (PFMI) and the In-Space Soldering Investigation (ISSI). The capabilities of these facilities are briefly discussed and then demonstrated by presenting "real-time" and subsequently down-linked video-taped examples from the abovementioned experiments. Data interpretation, ISS telescience, some lessons learned, and the need of such facilities for conducting work in support of understanding materials behavior, particularly fluid processing and transport scenarios, in low-gravity environments is discussed.

Materials Research Conducted Aboard the International Space Station: Facilities Overview, Operational Procedures, and Experimental Outcomes

NASA Technical Reports Server (NTRS)

Grugel, R. N.; Luz, P.; Smith, G. A.; Spivey, R.; Jeter, L.; Gillies, D. C.; Hua, F.; Anilkumar, A. V.

2006-01-01

The Microgravity Science Glovebox (MSG) and Maintenance Work Area (MWA) are facilities aboard the International Space Station (ISS) that were used to successfully conduct experiments in support of, respectively, the Pore Formation and Mobility Investigation (PFMI) and the In-Space Soldering Investigation (ISSI). The capabilities of these facilities are briefly discussed and then demonstrated by presenting real-time and subsequently down-linked video-taped examples from the abovementioned experiments. Data interpretation, ISS telescience, some lessons learned, and the need of such facilities for conducting work in support of understanding materials behavior, particularly fluid processing and transport scenarios, in low-gravity environments is discussed.

Experimental Investigation of Turbojet Thrust Augmentation Using an Ejector

DTIC Science & Technology

2007-03-01

mechanisms in which a particle can exchange energy. Thrust augmenting devices can be divided into two categories: ones that exchange net work or heat and...two categories from the energy equation discussion above. Thrust augmentation is achieved through turbulent entrainment where work and/or heat is...front sustained by compression waves from a trailing reaction zone. A deflagration wave is a subsonic flame front sustained by heat transfer

On the Learning of Mathematics Through Conversation.

ERIC Educational Resources Information Center

Haroutunian-Gordan, Sophie; Tartakoff, David S.

1996-01-01

Describes an experimental mathematics course involving an interpretive discussion approach in which students and instructors work together to develop questions about the meaning of mathematical, philosophical, and musical texts. Appendix contains a cluster of questions for Euclid's proof of the infinity of prime numbers. (MKR)

Old Wine into New Bottles.

ERIC Educational Resources Information Center

Crandall, G. Douglas

1997-01-01

Discusses how traditional lab exercises can be converted into investigative exercises. Describes an exercise on seed germination that has students design their own experiments based on their initial results. Involves students in the scientific process and allows them to experience the joys and disappointments of experimental work. (JRH)

Supersonic flow with feeding of energy

NASA Technical Reports Server (NTRS)

Zaremba, W.

1985-01-01

The present work discusses the results of some experimental studies on the possibility of attenuating shock waves in a supersonic flow. The shock waves were formed by an external source of electrical energy. An electromechanical method is described that permits partial recovery of the expended energy.

Physiological responses to environmental factors related to space flight

NASA Technical Reports Server (NTRS)

Pace, N.

1972-01-01

The research is reported for establishing physiological base line data, and for developing procedures and instrumentation necessary for the automatic measurement of hemodynamic and metabolic parameters. The work in the following areas is discussed: biochemistry, bioinstrumentation, nutrition, physiology, experimental surgery, and animal colony.

(Boiling water reactor (BWR) CORA experiments)

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

Ott, L.J.

To participate in the 1990 CORA Workshop at Kernforschungszentrum Karlsruhe (KfK) GmbH, Karlsruhe, FRG, on October 1--4, and to participate in detailed discussions on October 5 with the KfK CORA Boiling Water Reactor (BWR) experiments. The traveler attended the 1990 CORA Workshop at KfK, FRG. Participation included the presentation of a paper on work performed by the Boiling Water Reactor Core Melt Progression Phenomena Program at Oak Ridge National Laboratory (ORNL) on posttest analyses of CORA BWR experiments. The Statement of Work (November 1989) for the BWR Core Melt Progression Phenomena Program provides for pretest and posttest analyses of themore » BWR CORA experiments performed at KfK. Additionally, it is intended that ORNL personnel participate in the planning process for future CORA BWR experiments. For these purposes, meetings were held with KfK staff to discuss such topics as (1) experimental test schedule, (2) BWR test conduct, (3) perceived BWR experimental needs, and (4) KfK operational staff needs with respect to ORNL support. 19 refs.« less

Structural Dynamics Experimental Activities in Ultra-Lightweight and Inflatable Space Structures

NASA Technical Reports Server (NTRS)

Pappa, Richard S.; Lassiter, John O.; Ross, Brian P.

2001-01-01

This paper reports recently completed structural dynamics experimental activities with new ultralightweight and inflatable space structures (a.k.a., "Gossamer" spacecraft) at NASA Langley Research Center, NASA Marshall Space Flight Center, and NASA Goddard Space Flight Center. Nine aspects of this work are covered, as follows: 1) inflated, rigidized tubes, 2) active control experiments, 3) photogrammetry, 4) laser vibrometry, 5) modal tests of inflatable structures, 6) in-vacuum modal tests, 7) tensioned membranes, 8) deployment tests, and 9) flight experiment support. Structural dynamics will play a major role in the design and eventual in-space deployment and performance of Gossamer spacecraft, and experimental R&D work such as this is required now to validate new analytical prediction methods. The activities discussed in the paper are pathfinder accomplishments, conducted on unique components and prototypes of future spacecraft systems.

A New Two-Step Approach for Hands-On Teaching of Gene Technology: Effects on Students' Activities During Experimentation in an Outreach Gene Technology Lab

NASA Astrophysics Data System (ADS)

Scharfenberg, Franz-Josef; Bogner, Franz X.

2011-08-01

Emphasis on improving higher level biology education continues. A new two-step approach to the experimental phases within an outreach gene technology lab, derived from cognitive load theory, is presented. We compared our approach using a quasi-experimental design with the conventional one-step mode. The difference consisted of additional focused discussions combined with students writing down their ideas (step one) prior to starting any experimental procedure (step two). We monitored students' activities during the experimental phases by continuously videotaping 20 work groups within each approach ( N = 131). Subsequent classification of students' activities yielded 10 categories (with well-fitting intra- and inter-observer scores with respect to reliability). Based on the students' individual time budgets, we evaluated students' roles during experimentation from their prevalent activities (by independently using two cluster analysis methods). Independently of the approach, two common clusters emerged, which we labeled as `all-rounders' and as `passive students', and two clusters specific to each approach: `observers' as well as `high-experimenters' were identified only within the one-step approach whereas under the two-step conditions `managers' and `scribes' were identified. Potential changes in group-leadership style during experimentation are discussed, and conclusions for optimizing science teaching are drawn.

Hydrogen as an atomic beam standard

NASA Technical Reports Server (NTRS)

Peters, H. E.

1972-01-01

After a preliminary discussion of feasibility, new experimental work with a hydrogen beam is described. A space focused magnetic resonance technique with separated oscillatory fields is used with a monochromatic beam of cold hydrogen atoms which are selected from a higher temperature source. The first resonance curves and other experimental results are presented. These results are interpreted from the point of view of accuracy potential and frequency stability, and are compared with hydrogen maser and cesium beam capabilities.

Animal experimentation in Spacelab - Present and future U.S. plans

NASA Technical Reports Server (NTRS)

Berry, W. E.; Dant, C. C.

1983-01-01

Current development of life-sciences hardware and experiments for the fourth Spacelab mission in the Life Sciences Flight Experiments Program at NASA Ames is reviewed. The research-animal holding facility, the general-purpose work station, and the life sciences laboratory equipment are characterized, and the 14 Ames projects accepted for the mission are listed and discussed. Several hardware systems and experimental procedures will be verified on the Spacelab-3 mission scheduled for late 1984.

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

Vonach, H.; Tagesen, S.

Starting with a discussion of the requirements and goals for high quality general-purpose evaluations the paper will describe the procedures chosen in our evaluation work for JEFF for producing new general evaluations with complete covariance information for all cross sections (file 3 data). Key problems essential for the goal of making the best possible use of the existing theoretical and experimental knowledge on neutron interactions with the respective nuclide will be addressed, especially the problem of assigning covariances to calculated cross sections, necessary checking procedures for all experimental data and various possibilities to amend the experimental database beyond the obviousmore » use of EXFOR data for the respective cross sections. In this respect both, the use of elemental cross sections in isotopic evaluations and the use of implicit cross-section data (that is data which can be converted into cross sections by simple methods) will be discussed in some detail.« less

The halogen bond: Nature and applications

NASA Astrophysics Data System (ADS)

Costa, Paulo J.

2017-10-01

The halogen bond, corresponding to an attractive interaction between an electrophilic region in a halogen (X) and a nucleophile (B) yielding a R-X⋯B contact, found applications in many fields such as supramolecular chemistry, crystal engineering, medicinal chemistry, and chemical biology. Their large range of applications also led to an increased interest in their study using computational methods aiming not only at understanding the phenomena at a fundamental level, but also to help in the interpretation of results and guide the experimental work. Herein, a succinct overview of the recent theoretical and experimental developments is given starting by discussing the nature of the halogen bond and the latest theoretical insights on this topic. Then, the effects of the surrounding environment on halogen bonds are presented followed by a presentation of the available method benchmarks. Finally, recent experimental applications where the contribution of computational chemistry was fundamental are discussed, thus highlighting the synergy between the lab and modeling techniques.

Eye Safety in Dentistry and Associated Liability.

PubMed

Arsenault, Peter; Tayebi, Amad

2016-01-01

The first objective of this article is to expressan experimental-work-supported opinion ofits authors regarding the inadequacy of thepresent dental mask and regular eyewearcombination for protecting dental care practitioners. Its second objective is to suggestamending OSHA Standard 1910.133(a)(1) tomandate effective eye protection for dentalcare practitioners by requiring the use ofeffective means for closing the bottom gapsbetween the lower rims of the lenses of theprotective eyewear and the upper edge ofthe mask worn by the practitioner.The various types and sources of dentalpractice eye occupational hazards and thepossible entry routes of dental debris towarddental practitioners'eyes are discussed.Experimental work, confirming theinadequacy of the present dental mask andeyewear combination for protecting dentalcare practitioners, is presented.

Happy Birthday, Thomas Edison!

ERIC Educational Resources Information Center

Dalton, Edward A.

1997-01-01

Discusses the work and inventions of Thomas Edison and their use in making teachers and students aware of the importance of electrotechnology in their lives and in their futures. Enables students to learn about science, experimentation, research, the process of invention, and the thrill of discovery. Describes educational resources available from…

Group-Level Formative Feedback and Metadiscourse

ERIC Educational Resources Information Center

Resendes, Monica; Scardamalia, Marlene; Bereiter, Carl; Chen, Bodong; Halewood, Cindy

2015-01-01

This research explores the ability of grade 2 students to engage in productive discussion about the state of their knowledge building using group-level feedback tools to support their metadiscourse. Two aspects of knowledge work were common to the comparison and experimental classes: "Knowledge Building talk" (KB talk) involving…

Teaching Classical Mechanics Concepts Using Visuo-Haptic Simulators

ERIC Educational Resources Information Center

Neri, Luis; Noguez, Julieta; Robledo-Rella, Victor; Escobar-Castillejos, David; Gonzalez-Nucamendi, Andres

2018-01-01

In this work, the design and implementation of several physics scenarios using haptic devices are presented and discussed. Four visuo-haptic applications were developed for an undergraduate engineering physics course. Experiments with experimental and control groups were designed and implemented. Activities and exercises related to classical…

PREP-T1 (Preteen Re-Education With Parents-Type 1 Diabetes) Feasibility Intervention Results.

PubMed

Sullivan-Bolyai, Susan; Crawford, Sybil; Johnson, Kim; Ramchandani, Neesha; Quinn, Diane; D'Alesandro, Bianca; Stern, Kailyn; Lipman, Terry; Melkus, Gail; Streisand, Randi

2016-11-01

There has been a 2% to 3% increase in Type 1 diabetes (T1D) in children below 11 years old. Preteens (9-12 years old) with T1D are often overlooked regarding future diabetes self-management (DSM) expectations because parents are still in the "driver's seat." The study purpose was to explore feasibility/ability to recruit and conduct a two-arm trial on reeducation, collaboration, and social support. One component of DSM was reviewed (hypoglycemia) with preteens (n = 22) and parents (n = 22). The experimental preteens discussed hypoglycemia management with a teen mentor and nurse educator using a human patient simulator for practice, and working collaboratively with parents. Concurrently, mothers met with a parent mentor and psychologist to discuss growth and development, and collaborative shared management. Comparison dyads discussed hypoglycemia management with a nurse. Preteens slightly improved in diabetes knowledge; the experimental arm had higher problem-solving scores. Parents in the experimental arm had higher self-efficacy scores. Findings will inform future research. © The Author(s) 2016.

Reducing physical size limits for low-frequency horn loudspeaker systems

NASA Astrophysics Data System (ADS)

Honeycutt, Richard Allison

From 1881 until the present day, many excellent scholars have studied acoustic horns. This dissertation begins by discussing over eighty results of such study. Next, the methods of modeling horn behavior are examined with an emphasis on the prediction of throat impedance. Because of the time constraints in a product-design environment, in which the results of this study may be used, boundary-element and cascaded-section types of analysis were not considered due to their time intensiveness. Of the methods studied, an analytical process based upon Olson's adaptation of Webster's analysis is selected as the most accurate of the rapid methods, although other good methods exist. Reasons and extent of inaccuracy are discussed. The concept of interleaved horn loading is introduced: it involves using two horns of different parameters, fed by a single driver, with a view toward interleaving and thus smoothing the impedance peaks of the separate horns to produce a smoother response. The validity of the technique is demonstrated both theoretically and practically. Then the reactance annulling technique is explained and tested experimentally. It is found to work well, but the exact parameter values involved are not found to be critical. Finally, the considerations involved in building a practical working system are discussed, and a preliminary working model reviewed. Future work could be directed toward finding the optimum parameter values for the two "parallel horns" whose impedances are to be interleaved, as well as the system parameters that determine these optimum values. Also, further experimental investigation or ported loading of the back air chamber would be useful.

Motor Control of Two Flywheels Enabling Combined Attitude Control and Bus Regulation

NASA Technical Reports Server (NTRS)

Kenny, Barbara H.

2004-01-01

This presentation discussed the flywheel technology development work that is ongoing at NASA GRC with a particular emphasis on the flywheel system control. The "field orientation" motor/generator control algorithm was discussed and explained. The position-sensorless angle and speed estimation algorithm was presented. The motor current response to a step change in command at low (10 kRPM) and high (60 kRPM) was discussed. The flywheel DC bus regulation control was explained and experimental results presented. Finally, the combined attitude control and energy storage algorithm that controls two flywheels simultaneously was presented. Experimental results were shown that verified the operational capability of the algorithm. shows high speed flywheel energy storage (60,000 RPM) and the successful implementation of an algorithm to simultaneously control both energy storage and a single axis of attitude with two flywheels. Overall, the presentation demonstrated that GRC has an operational facility that

NASA Lidar system support and MOPA technology demonstration

NASA Technical Reports Server (NTRS)

Laughman, L. M.; Capuano, B.; Wayne, R. J.

1986-01-01

A series of lidar design and technology demonstration tasks in support of a CO2 lidar program is discussed. The first of these tasks is discussed in Section VI of this report under the heading of NASA Optical Lidar Design and it consists of detailed recommendations for the layout of a CO2 Doppler lidar incorporating then existing NASA optical components and mounts. The second phase of this work consisted of the design, development, and delivery to NASA of a novel acousto-optic laser frequency stabilization system for use with the existing NASA ring laser transmitter. The second major task in this program encompasses the design and experimental demonstration of a master oscillator-power amplifier (MOPA) laser transmitter utilizing a commercially available laser as the amplifier. The MOPA design including the low chirp master oscillator is discussed in detail. Experimental results are given for one, two and three pass amplification. The report includes operating procedures for the MOPA system.

Ultrasonic geometrical characterization of periodically corrugated surfaces.

PubMed

Liu, Jingfei; Declercq, Nico F

2013-04-01

Accurate characterization of the characteristic dimensions of a periodically corrugated surface using ultrasonic imaging technique is investigated both theoretically and experimentally. The possibility of accurately characterizing the characteristic dimensions is discussed. The condition for accurate characterization and the quantitative relationship between the accuracy and its determining parameters are given. The strategies to avoid diffraction effects instigated by the periodical nature of a corrugated surface are also discussed. Major causes of erroneous measurements are theoretically discussed and experimentally illustrated. A comparison is made between the presented results and the optical measurements, revealing acceptable agreement. This work realistically exposes the capability of the proposed ultrasonic technique to accurately characterize the lateral and vertical characteristic dimensions of corrugated surfaces. Both the general principles developed theoretically as well as the proposed practical techniques may serve as useful guidelines to peers. Copyright © 2012 Elsevier B.V. All rights reserved.

The Observational Status of Cosmic Inflation After Planck

NASA Astrophysics Data System (ADS)

Martin, Jérôme

The observational status of inflation after the Planck 2013 and 2015 results and the BICEP2/Keck Array and Planck joint analysis is discussed. These pedagogical lecture notes are intended to serve as a technical guide filling the gap between the theoretical articles on inflation and the experimental works on astrophysical and cosmological data. After a short discussion of the central tenets at the basis of inflation (negative self-gravitating pressure) and its experimental verifications, it reviews how the most recent Cosmic Microwave Background (CMB) anisotropy measurements constrain cosmic inflation. The fact that vanilla inflationary models are, so far, preferred by the observations is discussed and the reason why plateau-like potential versions of inflation are favored within this subclass of scenarios is explained. Finally, how well the future measurements, in particular of B-Mode CMB polarization or primordial gravity waves, will help to improve our knowledge about inflation is also investigated.

High efficiency IR supercontinuum generation and applications: a review

NASA Astrophysics Data System (ADS)

Yin, Shizhuo; Ruffin, Paul; Brantley, Christina; Edwards, Eugene; Cheng, Jiping; Yao, Jimmy; Luo, Claire

2011-10-01

In this paper, we have reviewed our recent works on IR supercontinuum generation (SCG) and its applications. First, we provide a brief review on the physical mechanism of the supercontinuum generation and our previous works in this field. Second, the transmission characteristics of a new type of IR fibers is presented. Furthermore, the SCG generation in this new type of optical fiber is experimentally demonstrated. Finally, the suggestion for the future effort is discussed.

Engineering of Organic Nanocrystals by Electrocrystallization

NASA Astrophysics Data System (ADS)

Kilani, Mohamed

This work discusses the experimental and theoretical methods used to control the morphology of nanocrystals. The hypothesis of the thermodynamic/kinetic control of the morphology was verified. We applied the electrocrystallization to make K(def)TCP nanocrystals and we tuned the electrochemical parameters to determine their influence on the nanocrystals morphologies. The characterization was mainly performed with AFM and FE-SEM. We presented in this work the possibility to control the morphology of K(def)TCP using the electrochemical parameters. The obtained shapes ranged from nanorods to rhombohedral shape, which is reported for the first time. The observed growth behavior was modeled and simulated with a method based on Monte-Carlo techniques. The simulation results show a qualitative match with the experimental findings. This work contributes to the understanding of the crystal growth behavior and the thermodynamic/kinetic morphology transition using electrocrystallization.

Hardware Implementation of Maximum Power Point Tracking for Thermoelectric Generators

NASA Astrophysics Data System (ADS)

Maganga, Othman; Phillip, Navneesh; Burnham, Keith J.; Montecucco, Andrea; Siviter, Jonathan; Knox, Andrew; Simpson, Kevin

2014-06-01

This work describes the practical implementation of two maximum power point tracking (MPPT) algorithms, namely those of perturb and observe, and extremum seeking control. The proprietary dSPACE system is used to perform hardware in the loop (HIL) simulation whereby the two control algorithms are implemented using the MATLAB/Simulink (Mathworks, Natick, MA) software environment in order to control a synchronous buck-boost converter connected to two commercial thermoelectric modules. The process of performing HIL simulation using dSPACE is discussed, and a comparison between experimental and simulated results is highlighted. The experimental results demonstrate the validity of the two MPPT algorithms, and in conclusion the benefits and limitations of real-time implementation of MPPT controllers using dSPACE are discussed.

Heat transfer to the transpired turbulent boundary layer.

NASA Technical Reports Server (NTRS)

Kays, W. M.

1972-01-01

This paper contains a summarization of five years work on an investigation on heat transfer to the transpired turbulent boundary layer. Experimental results are presented for friction coefficient and Stanton number over a wide range of blowing and suction for the case of constant free-stream velocity, holding certain blowing parameters constant. The problem of the accelerated turbulent boundary layer with transpiration is considered, experimental data are presented and discussed, and theoretical models for solution of the momentum equation under these conditions are presented. Data on turbulent Prandtl number are presented so that solutions to the energy equation may be obtained. Some examples of boundary layer heat transfer and friction coefficient predictions are presented using one of the models discussed, employing a finite difference solution method.

Investigation of free-forced convection flows in cavity-type receivers. Final yearly report, 1979-1980

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

Humphrey, J.A.C.

1982-01-01

A summary is provided of the first of three years of experimental and theoretical research on free-forced convection flows in cavity-type solar receivers. New experimental and theoretical results are presented and discussed. The implication of these findings, with respect to the future thrust of the research program, is clarified as well as is possible at the present time. Following various related conclusions a summary and tentative schedule of work projected for year two of research are presented.

Breath air measurement using wide-band frequency tuning IR laser photo-acoustic spectroscopy

NASA Astrophysics Data System (ADS)

Kistenev, Yury V.; Borisov, Alexey V.; Kuzmin, Dmitry A.; Bulanova, Anna A.; Boyko, Andrey A.; Kostyukova, Nadezhda Y.; Karapuzikov, Alexey A.

2016-03-01

The results of measuring of biomarkers in breath air of patients with broncho-pulmonary diseases using wide-band frequency tuning IR laser photo-acoustic spectroscopy and the methods of data mining are presented. We will discuss experimental equipment and various methods of intellectual analysis of the experimental spectra in context of above task. The work was carried out with partial financial support of the FCPIR contract No 14.578.21.0082 (ID RFMEFI57814X0082).

Direct experimental observation of nonclassicality in ensembles of single-photon emitters

NASA Astrophysics Data System (ADS)

Moreva, E.; Traina, P.; Forneris, J.; Degiovanni, I. P.; Ditalia Tchernij, S.; Picollo, F.; Brida, G.; Olivero, P.; Genovese, M.

2017-11-01

In this work we experimentally demonstrate a recently proposed criterion addressed to detect nonclassical behavior in the fluorescence emission of ensembles of single-photon emitters. In particular, we apply the method to study clusters of nitrogen-vacancy centers in diamond characterized with single-photon-sensitive confocal microscopy. Theoretical considerations on the behavior of the parameter at any arbitrary order in the presence of Poissonian noise are presented and, finally, the opportunity of detecting manifold coincidences is discussed.

Experimental and analytical study of close-coupled ventral nozzles for ASTOVL aircraft

NASA Technical Reports Server (NTRS)

Mcardle, Jack G.; Smith, C. Frederic

1990-01-01

Flow in a generic ventral nozzle system was studied experimentally and analytically with a block version of the PARC3D computational fluid dynamics program (a full Navier-Stokes equation solver) in order to evaluate the program's ability to predict system performance and internal flow patterns. For the experimental work a one-third-size model tailpipe with a single large rectangular ventral nozzle mounted normal to the tailpipe axis was tested with unheated air at steady-state pressure ratios up to 4.0. The end of the tailpipe was closed to simulate a blocked exhaust nozzle. Measurements showed about 5 1/2 percent flow-turning loss, reasonable nozzle performance coefficients, and a significant aftward axial component of thrust due to flow turning loss, reasonable nozzle performance coefficients, and a significant aftward axial component of thrust due to flow turning more than 90 deg. Flow behavior into and through the ventral duct is discussed and illustrated with paint streak flow visualization photographs. For the analytical work the same ventral system configuration was modeled with two computational grids to evaluate the effect of grid density. Both grids gave good results. The finer-grid solution produced more detailed flow patterns and predicted performance parameters, such as thrust and discharge coefficient, within 1 percent of the measured values. PARC3D flow visualization images are shown for comparison with the paint streak photographs. Modeling and computational issues encountered in the analytical work are discussed.

Strategic directions and mechanisms in technology transfer

NASA Technical Reports Server (NTRS)

Mackin, Robert

1992-01-01

An outline summarizing the Working Panel discussion related to strategic directions for technology transfer is presented. Specific topics addressed include measuring success, management of technology, innovation and experimentation in the tech transfer process, integration of tech transfer into R&D planning, institutionalization of tech transfer, and policy/legislative resources.

Atmosphere, Science (Experimental): 5343.08.

ERIC Educational Resources Information Center

Reese, Sandra Kay

This unit of instruction deals with a study of the general atmosphere by layers with an emphasis on physical characteristics. The formation of layers in the atmosphere and the energy relationships that exist between them are also discussed. No requisites for prior course work, experience, or courses to be taken concurrently are required for…

General Physics as a Major

ERIC Educational Resources Information Center

Peckham, Donald C.; Romer, Alfred

1976-01-01

A three-year general physics program which uses a single text from which a sequence of one-year courses have been constructed is described. It is organized on a modified spiral approach and requires laboratory work culminating in an experimental project during the sixth semester. Discussion includes implementation and administration of the…

The e-Beam Sustained Laser Technology for Space-based Doppler Wind Lidar

NASA Technical Reports Server (NTRS)

Brown, M. J.; Holman, W.; Robinson, R. J.; Schwarzenberger, P. M.; Smith, I. M.; Wallace, S.; Harris, M. R.; Willetts, D. V.; Kurzius, S. C.

1992-01-01

An overview is presented of GEC Avionics activities relating to the Spaceborne Doppler Wind Lidar. In particular, the results of design studies into the use of an e-beam sustained CO2 laser for spaceborne applications, and experimental work on a test bed system are discussed.

An Integrated Strategy for an Apparel Design Curriculum

ERIC Educational Resources Information Center

Bye, Elizabeth; Labat, Karen L.

2005-01-01

The core of apparel design education is the studio experience. This article discusses an Integrated Apparel Design Curriculum model built on a foundation of creative and technical experimentation and learning which contributes to developing abstract thinking skills. Various learning styles are supported as students work through the design process…

On Generating Knowledge in Service to Society

ERIC Educational Resources Information Center

Schwandt, Thomas A.

2005-01-01

In the US debate over science-based educational research, experimentation is again coming to the fore as ideal for establishing an evidence base of what works in educational interventions thus contributing to the climate of accountability in educational research and practice. Mixed methods research is being positioned in this discussion as a…

75 FR 9590 - Environmental Management Site-Specific Advisory Board, Idaho National Laboratory

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-03

... current agenda): Progress to Cleanup. InSitu Grouting--Work Plan Follow-up Discussion. Experimental... meeting be announced in the Federal Register. DATES: Tuesday, March 16, 2010, 8 a.m.-5 p.m. Opportunities... in the areas of environmental restoration, waste management, and related activities. Tentative Topics...

Student decision making in large group discussion

NASA Astrophysics Data System (ADS)

Kustusch, Mary Bridget; Ptak, Corey; Sayre, Eleanor C.; Franklin, Scott V.

2015-04-01

It is increasingly common in physics classes for students to work together to solve problems and perform laboratory experiments. When students work together, they need to negotiate the roles and decision making within the group. We examine how a large group of students negotiates authority as part of their two week summer College Readiness Program at Rochester Institute of Technology. The program is designed to develop metacognitive skills in first generation and Deaf and hard-of-hearing (DHH) STEM undergraduates through cooperative group work, laboratory experimentation, and explicit reflection exercises. On the first full day of the program, the students collaboratively developed a sign for the word ``metacognition'' for which there is not a sign in American Sign Language. This presentation will focus on three aspects of the ensuing discussion: (1) how the instructor communicated expectations about decision making; (2) how the instructor promoted student-driven decision making rather than instructor-driven policy; and (3) one student's shifts in decision making behavior. We conclude by discussing implications of this research for activity-based physics instruction.

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

Mattsson, Ann E.

Density Functional Theory (DFT) based Equation of State (EOS) construction is a prominent part of Sandia’s capabilities to support engineering sciences. This capability is based on augmenting experimental data with information gained from computational investigations, especially in those parts of the phase space where experimental data is hard, dangerous, or expensive to obtain. A key part of the success of the Sandia approach is the fundamental science work supporting the computational capability. Not only does this work enhance the capability to perform highly accurate calculations but it also provides crucial insight into the limitations of the computational tools, providing highmore » confidence in the results even where results cannot be, or have not yet been, validated by experimental data. This report concerns the key ingredient of projector augmented-wave (PAW) potentials for use in pseudo-potential computational codes. Using the tools discussed in SAND2012-7389 we assess the standard Vienna Ab-initio Simulation Package (VASP) PAWs for Molybdenum.« less

Toward a multiscale modeling framework for understanding serotonergic function

PubMed Central

Wong-Lin, KongFatt; Wang, Da-Hui; Moustafa, Ahmed A; Cohen, Jeremiah Y; Nakamura, Kae

2017-01-01

Despite its importance in regulating emotion and mental wellbeing, the complex structure and function of the serotonergic system present formidable challenges toward understanding its mechanisms. In this paper, we review studies investigating the interactions between serotonergic and related brain systems and their behavior at multiple scales, with a focus on biologically-based computational modeling. We first discuss serotonergic intracellular signaling and neuronal excitability, followed by neuronal circuit and systems levels. At each level of organization, we will discuss the experimental work accompanied by related computational modeling work. We then suggest that a multiscale modeling approach that integrates the various levels of neurobiological organization could potentially transform the way we understand the complex functions associated with serotonin. PMID:28417684

Experimental micro mechanics methods for conventional and negative Poisson's ratio cellular solids as Cosserat continua

NASA Technical Reports Server (NTRS)

Lakes, R.

1991-01-01

Continuum representations of micromechanical phenomena in structured materials are described, with emphasis on cellular solids. These phenomena are interpreted in light of Cosserat elasticity, a generalized continuum theory which admits degrees of freedom not present in classical elasticity. These are the rotation of points in the material, and a couple per unit area or couple stress. Experimental work in this area is reviewed, and other interpretation schemes are discussed. The applicability of Cosserat elasticity to cellular solids and fibrous composite materials is considered as is the application of related generalized continuum theories. New experimental results are presented for foam materials with negative Poisson's ratios.

Fiber-Drawn Metamaterial for THz Waveguiding and Imaging

NASA Astrophysics Data System (ADS)

Atakaramians, Shaghik; Stefani, Alessio; Li, Haisu; Habib, Md. Samiul; Hayashi, Juliano Grigoleto; Tuniz, Alessandro; Tang, Xiaoli; Anthony, Jessienta; Lwin, Richard; Argyros, Alexander; Fleming, Simon C.; Kuhlmey, Boris T.

2017-09-01

In this paper, we review the work of our group in fabricating metamaterials for terahertz (THz) applications by fiber drawing. We discuss the fabrication technique and the structures that can be obtained before focusing on two particular applications of terahertz metamaterials, i.e., waveguiding and sub-diffraction imaging. We show the experimental demonstration of THz radiation guidance through hollow core waveguides with metamaterial cladding, where substantial improvements were realized compared to conventional hollow core waveguides, such as reduction of size, greater flexibility, increased single-mode operating regime, and guiding due to magnetic and electric resonances. We also report recent and new experimental work on near- and far-field THz imaging using wire array metamaterials that are capable of resolving features as small as λ/28.

Numerical Study of Tip Vortex Flows

NASA Technical Reports Server (NTRS)

Dacles-Mariani, Jennifer; Hafez, Mohamed

1998-01-01

This paper presents an overview and summary of the many different research work related to tip vortex flows and wake/trailing vortices as applied to practical engineering problems. As a literature survey paper, it outlines relevant analytical, theoretical, experimental and computational study found in literature. It also discusses in brief some of the fundamental aspects of the physics and its complexities. An appendix is also included. The topics included in this paper are: 1) Analytical Vortices; 2) Experimental Studies; 3) Computational Studies; 4) Wake Vortex Control and Management; 5) Wake Modeling; 6) High-Lift Systems; 7) Issues in Numerical Studies; 8) Instabilities; 9) Related Topics; 10) Visualization Tools for Vertical Flows; 11) Further Work Needed; 12) Acknowledgements; 13) References; and 14) Appendix.

Experimental liver fibrosis research: update on animal models, legal issues and translational aspects

PubMed Central

2013-01-01

Liver fibrosis is defined as excessive extracellular matrix deposition and is based on complex interactions between matrix-producing hepatic stellate cells and an abundance of liver-resident and infiltrating cells. Investigation of these processes requires in vitro and in vivo experimental work in animals. However, the use of animals in translational research will be increasingly challenged, at least in countries of the European Union, because of the adoption of new animal welfare rules in 2013. These rules will create an urgent need for optimized standard operating procedures regarding animal experimentation and improved international communication in the liver fibrosis community. This review gives an update on current animal models, techniques and underlying pathomechanisms with the aim of fostering a critical discussion of the limitations and potential of up-to-date animal experimentation. We discuss potential complications in experimental liver fibrosis and provide examples of how the findings of studies in which these models are used can be translated to human disease and therapy. In this review, we want to motivate the international community to design more standardized animal models which might help to address the legally requested replacement, refinement and reduction of animals in fibrosis research. PMID:24274743

Membrane Vibration Studies Using a Scanning Laser Vibrometer

NASA Technical Reports Server (NTRS)

Gaspar, James L.; Solter, Micah J.; Pappa, Richard S.

2001-01-01

This paper summarizes on-going experimental work at NASA Langley Research Center to measure the dynamics of a 1.016 m (40 in.) square polyimide film Kapton membrane. A fixed fully automated impact hammer and Polytec PSV-300-H scanning laser vibrometer were used for non-contact modal testing of the membrane with zero-mass-loading. The paper discusses the results obtained by testing the membrane at various tension levels and at various excitation locations. Results obtained by direct shaker excitation to the membrane are also discussed.

The Microscale Synthesis and Electrochemistry of Low-Valent Mononuclear Complexes (h3-C3H5)Fe(CO)3 X (X = I, Br, Cl)

NASA Astrophysics Data System (ADS)

Mocellin, Enrico; Russell, Richard; Ravera, Mauro

1998-06-01

The experimental content of this paper will appeal to pedagogues and students who might be looking for new ideas that have an element of challenge. By combining experimental procedures which place microscale, chemical synthesis, and an inclusive, unified, product characterization in perspective, we have afforded the student the scope to obtain progressive, disciplined results and the opportunity to discuss these in the subsequent reporting. By this process, it is our experience that the students often identify with the practical work that is being undertaken, and they develop considerable empathy during their contribution to the "discovery" process that this laboratory program offers. The experimental work can be abbreviated to a single compound, subdivided into synthesis or electrochemistry, or extended to macroscale and other instrumental techniques of characterization, thus offering opportunities to accommodate time constraints, class results combination and discussion, and individual student enthusiasm. We believe that having to accept and/or constructively criticize sequential experimental results, collected by fellow students, mimics more realistically the practice of chemistry at the workplace and can build enthusiasm and elicit contagious fellowship from the class. All of these aspects can simply be achieved by utilizing the listed journals and references therein. Most importantly, it affords the students the opportunity to extricate themselves as innocent bystanders from the conventional "single experiment" practical laboratory to a path of practice and achievement in the scientific method.

The Effectiveness of University Counselling for Improving Academic Outcomes and Well-Being

ERIC Educational Resources Information Center

Biasi, Valeria; Patrizi, Nazarena; Mosca, Mauro; De Vincenzo, Conny

2017-01-01

The work discusses the effectiveness of the counselling treatment to enhance student academic success. The participants were randomly assigned to either an experimental group (66 students who had completed counselling treatment) or a wait-list comparison group (44 students). The Adult Self Report (ASR) by Achenbach and Rescorla [2003. "Manual…

Collisional depopulation of rubidium Rydberg states by ND/sub 3/

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

Petitjean, L.; Gounand, F.; Fournier, P.R.

1986-02-01

This paper reports the measurement of the depopulation cross sections of the Rb(ns) and Rb(nd) states by ND/sub 3/ (23< or =n< or =50). The experimental data are discussed with reference to previous work done on collisions between Rb(ns) and Rb(nd) states and NH/sub 3/.

Policy Issues in Computer Education. Assessing the Cognitive Consequences of Computer Environments for Learning (ACCCEL).

ERIC Educational Resources Information Center

Linn, Marcia

This paper analyzes the capabilities of the computer learning environment identified by the Assessing the Cognitive Consequences of Computer Environments for Learning (ACCCEL) Project, augments the analysis with experimental work, and discusses how schools can implement policies which provide for the maximum potential of computers. The ACCCEL…

Teaching Public Goods Theory with a Classroom Game

ERIC Educational Resources Information Center

Pickhardt, Michael

2005-01-01

The author extends the work of Holt and Laury (1997) on a simple noncomputerized card game for teaching the essential aspects of public goods theory. He suggests a course of several lectures and discusses the behavior of subjects in various game sessions. Among other things, the results provide experimental evidence with respect to the private…

Historical review of C-5A lift distribution control systems

NASA Technical Reports Server (NTRS)

Disney, T. E.; Eckholdt, D. C.

1976-01-01

Analytical and experimental development work on various load alleviation systems for the C-5A is reviewed to trace the development of the technical and hardware concepts to the present time. Variations in system objectives, means of implementation and effects on loads and airplane performance, stability and control are discussed.

The Earth's Core: How Does It Work? Perspectives in Science. Number 1.

ERIC Educational Resources Information Center

Carnegie Institution of Washington, Washington, DC.

Various research studies designed to enhance knowledge about the earth's core are discussed. Areas addressed include: (1) the discovery of the earth's core; (2) experimental approaches used in studying the earth's core (including shock-wave experiments and experiments at high static pressures), the search for the core's light elements, the…

Measuring general relativity effects in a terrestrial lab by means of laser gyroscopes

NASA Astrophysics Data System (ADS)

Beverini, N.; Allegrini, M.; Beghi, A.; Belfi, J.; Bouhadef, B.; Calamai, M.; Carelli, G.; Cuccato, D.; Di Virgilio, A.; Maccioni, E.; Ortolan, A.; Porzio, A.; Santagata, R.; Solimeno, S.; Tartaglia, A.

2014-07-01

GINGER is a proposed tridimensional array of laser gyroscopes with the aim of measuring the Lense-Thirring effect, predicted by the general relativity theory, in a terrestrial laboratory environment. We discuss the required accuracy, the methods to achieve it, and the preliminary experimental work in this direction.

The influence of defects and impurities on the nucleation and growth of oriented films by evaporation

NASA Technical Reports Server (NTRS)

Green, A. K.

1973-01-01

The influence of substrate imperfections on the nucleation and growth of fcc metals on alkali halides is discussed. Films deposited on well characterized substrated under well defined vacuum evaporation conditions are investigated. The experimental results of this work are correlated with similar work by other investigators. Models which have been proposed by various authors to explain experimental results are critically examined and areas of difficulty are pointed out. The influence of defects on nucleation rate and the orientation of the film is emphasized. Specific examples of impurity effects, irradiation effects and the influence of amorphous layers are discussed in detail. Evidence is shown that the formation of multiply twinned particles is a result of coalescence and growth. The only consistent model for the orienting influence of impurities is shown to be a chemical reaction effect. It is demonstrated that an alkali metal impurity is very likely responsible for the orienting influence of both water vapor exposure and irradiation. A negative result is found for the reported possibility of an orienting influence being transmitted through an amorphous layer.

Feasibility of MHD submarine propulsion

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

Doss, E.D.; Sikes, W.C.

1992-09-01

This report describes the work performed during Phase 1 and Phase 2 of the collaborative research program established between Argonne National Laboratory (ANL) and Newport News Shipbuilding and Dry Dock Company (NNS). Phase I of the program focused on the development of computer models for Magnetohydrodynamic (MHD) propulsion. Phase 2 focused on the experimental validation of the thruster performance models and the identification, through testing, of any phenomena which may impact the attractiveness of this propulsion system for shipboard applications. The report discusses in detail the work performed in Phase 2 of the program. In Phase 2, a two Teslamore » test facility was designed, built, and operated. The facility test loop, its components, and their design are presented. The test matrix and its rationale are discussed. Representative experimental results of the test program are presented, and are compared to computer model predictions. In general, the results of the tests and their comparison with the predictions indicate that thephenomena affecting the performance of MHD seawater thrusters are well understood and can be accurately predicted with the developed thruster computer models.« less

Exploring the science of thinking independently together: Faraday Discussion Volume 204 - Complex Molecular Surfaces and Interfaces, Sheffield, UK, July 2017.

PubMed

Samperi, M; Hirsch, B E; Diaz Fernandez, Y A

2017-11-23

The 2017 Faraday Discussion on Complex Molecular Surfaces and Interfaces brought together theoreticians and experimentalists from both physical and chemical backgrounds to discuss the relevant applied and fundamental research topics within the broader field of chemical surface analysis and characterization. Main discussion topics from the meeting included the importance of "disordered" two-dimensional (2D) molecular structures and the utility of kinetically trapped states. An emerging need for new experimental tools to address dynamics and kinetic pathways involved in self-assembled systems, as well as the future prospects and current limitations of in silico studies were also discussed. The following article provides a brief overview of the work presented and the challenges discussed during the meeting.

Increasing work-time influence: consequences for flexibility, variability, regularity and predictability.

PubMed

Nabe-Nielsen, Kirsten; Garde, Anne Helene; Aust, Birgit; Diderichsen, Finn

2012-01-01

This quasi-experimental study investigated how an intervention aiming at increasing eldercare workers' influence on their working hours affected the flexibility, variability, regularity and predictability of the working hours. We used baseline (n = 296) and follow-up (n = 274) questionnaire data and interviews with intervention-group participants (n = 32). The work units in the intervention group designed their own intervention comprising either implementation of computerised self-scheduling (subgroup A), collection of information about the employees' work-time preferences by questionnaires (subgroup B), or discussion of working hours (subgroup C). Only computerised self-scheduling changed the working hours and the way they were planned. These changes implied more flexible but less regular working hours and an experience of less predictability and less continuity in the care of clients and in the co-operation with colleagues. In subgroup B and C, the participants ended up discussing the potential consequences of more work-time influence without actually implementing any changes. Employee work-time influence may buffer the adverse effects of shift work. However, our intervention study suggested that while increasing the individual flexibility, increasing work-time influence may also result in decreased regularity of the working hours and less continuity in the care of clients and co-operation with colleagues.

Planar LTCC transformers for high voltage flyback converters.

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

Schofield, Daryl; Schare, Joshua M.; Glass, Sarah Jill

This paper discusses the design and use of low-temperature (850 C to 950 C) co-fired ceramic (LTCC) planar magnetic flyback transformers for applications that require conversion of a low voltage to high voltage (> 100V) with significant volumetric constraints. Measured performance and modeling results for multiple designs showed that the LTCC flyback transformer design and construction imposes serious limitations on the achievable coupling and significantly impacts the transformer performance and output voltage. This paper discusses the impact of various design factors that can provide improved performance by increasing transformer coupling and output voltage. The experiments performed on prototype units demonstratedmore » LTCC transformer designs capable of greater than 2 kV output. Finally, the work investigated the effect of the LTCC microstructure on transformer insulation. Although this paper focuses on generating voltages in the kV range, the experimental characterization and discussion presented in this work applies to designs requiring lower voltage.« less

Exhaust turbine and jet propulsion systems

NASA Technical Reports Server (NTRS)

Leist, Karl; Knornschild, Eugen

1951-01-01

DVL experimental and analytical work on the cooling of turbine blades by using ram air as the working fluid over a sector or sectors of the turbine annulus area is summarized. The subsonic performance of ram-jet, turbo-jet, and turbine-propeller engines with both constant pressure and pulsating-flow combustion is investigated. Comparison is made with the performance of a reciprocating engine and the advantages of the gas turbine and jet-propulsion engines are analyzed. Nacelle installation methods and power-level control are discussed.

The space shuttle payload planning working groups. Volume 6: Communications and navigation

NASA Technical Reports Server (NTRS)

1973-01-01

The findings of the Communications and Navigation working group of the space shuttle payload planning activity are presented. The basic goals to be accomplished are to increase the use of space systems and to develop new space capabilities for providing communication and navigation services to the user community in the 1980 time period. Specific experiments to be conducted for improving space communication and navigation capabilities are defined. The characteristics of the experimental equipment required to accomplish the mission are discussed.

Polarization Dependence of Surface Enhanced Raman Scattering on a Single Dielectric Nanowire

DTIC Science & Technology

2012-01-01

original work is properly cited. Our measurements of surface enhanced Raman scattering (SERS) on Ga2O3 dielectric nanowires (NWs) core/silver composites...process has been widely discussed [15–21]. In this work, a highly effective SERS composite of dielectric Ga2O3 NWs core/silver was employed to investigate...self-assembled monolayer of active SERS molecules on the NWs may affect the SERS enhancement as well. 2. Experimental Details Random Ga2O3 NWs were

From Ion Current to Electroosmotic Flow Rectification in Asymmetric Nanopore Membranes

PubMed Central

Wu, Xiaojian

2017-01-01

Asymmetrically shaped nanopores have been shown to rectify the ionic current flowing through pores in a fashion similar to a p-n junction in a solid-state diode. Such asymmetric nanopores include conical pores in polymeric membranes and pyramidal pores in mica membranes. We review here both theoretical and experimental aspects of this ion current rectification phenomenon. A simple intuitive model for rectification, stemming from previously published more quantitative models, is discussed. We also review experimental results on controlling the extent and sign of rectification. It was shown that ion current rectification produces a related rectification of electroosmotic flow (EOF) through asymmetric pore membranes. We review results that show how to measure and modulate this EOF rectification phenomenon. Finally, EOF rectification led to the development of an electroosmotic pump that works under alternating current (AC), as opposed to the currently available direct current EOF pumps. Experimental results on AC EOF rectification are reviewed, and advantages of using AC to drive EOF are discussed. PMID:29240676

From Ion Current to Electroosmotic Flow Rectification in Asymmetric Nanopore Membranes.

PubMed

Experton, Juliette; Wu, Xiaojian; Martin, Charles R

2017-12-14

Asymmetrically shaped nanopores have been shown to rectify the ionic current flowing through pores in a fashion similar to a p-n junction in a solid-state diode. Such asymmetric nanopores include conical pores in polymeric membranes and pyramidal pores in mica membranes. We review here both theoretical and experimental aspects of this ion current rectification phenomenon. A simple intuitive model for rectification, stemming from previously published more quantitative models, is discussed. We also review experimental results on controlling the extent and sign of rectification. It was shown that ion current rectification produces a related rectification of electroosmotic flow (EOF) through asymmetric pore membranes. We review results that show how to measure and modulate this EOF rectification phenomenon. Finally, EOF rectification led to the development of an electroosmotic pump that works under alternating current (AC), as opposed to the currently available direct current EOF pumps. Experimental results on AC EOF rectification are reviewed, and advantages of using AC to drive EOF are discussed.

Fiber Bragg Grating Dilatometry in Extreme Magnetic Field and Cryogenic Conditions

PubMed Central

Corvalán Moya, Carolina; Weickert, Franziska; Zapf, Vivien; Balakirev, Fedor F.; Wartenbe, Mark; Rosa, Priscila F. S.; Betts, Jonathan B.; Crooker, Scott A.; Daou, Ramzy

2017-01-01

In this work, we review single mode SiO2 fiber Bragg grating techniques for dilatometry studies of small single-crystalline samples in the extreme environments of very high, continuous, and pulsed magnetic fields of up to 150 T and at cryogenic temperatures down to <1 K. Distinct millimeter-long materials are measured as part of the technique development, including metallic, insulating, and radioactive compounds. Experimental strategies are discussed for the observation and analysis of the related thermal expansion and magnetostriction of materials, which can achieve a strain sensitivity (ΔL/L) as low as a few parts in one hundred million (≈10−8). The impact of experimental artifacts, such as those originating in the temperature dependence of the fiber’s index of diffraction, light polarization rotation in magnetic fields, and reduced strain transfer from millimeter-long specimens, is analyzed quantitatively using analytic models available in the literature. We compare the experimental results with model predictions in the small-sample limit, and discuss the uncovered discrepancies. PMID:29117137

Fiber Bragg Grating Dilatometry in Extreme Magnetic Field and Cryogenic Conditions.

PubMed

Jaime, Marcelo; Corvalán Moya, Carolina; Weickert, Franziska; Zapf, Vivien; Balakirev, Fedor F; Wartenbe, Mark; Rosa, Priscila F S; Betts, Jonathan B; Rodriguez, George; Crooker, Scott A; Daou, Ramzy

2017-11-08

In this work, we review single mode SiO₂ fiber Bragg grating techniques for dilatometry studies of small single-crystalline samples in the extreme environments of very high, continuous, and pulsed magnetic fields of up to 150 T and at cryogenic temperatures down to <1 K. Distinct millimeter-long materials are measured as part of the technique development, including metallic, insulating, and radioactive compounds. Experimental strategies are discussed for the observation and analysis of the related thermal expansion and magnetostriction of materials, which can achieve a strain sensitivity ( ΔL/L ) as low as a few parts in one hundred million (≈10 -8 ). The impact of experimental artifacts, such as those originating in the temperature dependence of the fiber's index of diffraction, light polarization rotation in magnetic fields, and reduced strain transfer from millimeter-long specimens, is analyzed quantitatively using analytic models available in the literature. We compare the experimental results with model predictions in the small-sample limit, and discuss the uncovered discrepancies.

Experimental gas-fired pulse-combustion studies

NASA Technical Reports Server (NTRS)

Blomquist, C. A.

1982-01-01

Experimental studies conducted at Argonne National Laboratory on a gas-fired, water-cooled, Helmholtz-type pulse combustion burner are discussed. In addition to the experimental work, information is presented on the evolution of pulse combustion, the types of pulse combustion burners and their applications, and the types of fuels used. Also included is a survey of other pertinent studies of gas-fired pulse combustion. The burner used in the Argonne research effort was equipped with adjustable air and gas flapper valves and was operated stably over a heat-input range of 30,000 to 200,000 Btu/h. The burner's overall heat transfer in the pulsating mode was 22 to 31% higher than when the unit was operated in the steady mode. Important phenomena discussed include (1) effects on performance produced by inserting a corebustor to change tailpipe diameter, (2) effects observed following addition of an air-inlet decoupling chamber to the unit, and (3) occurrence of carbon monoxide in the exhaust gas.

Fiber Bragg Grating Dilatometry in Extreme Magnetic Field and Cryogenic Conditions

DOE PAGES

Jaime, Marcelo; Corvalán Moya, Carolina; Weickert, Franziska; ...

2017-11-08

In this work, we review single mode SiO 2 fiber Bragg grating techniques for dilatometry studies of small single-crystalline samples in the extreme environments of very high, continuous, and pulsed magnetic fields of up to 150 T and at cryogenic temperatures down to <1 K. Distinct millimeter-long materials are measured as part of the technique development, including metallic, insulating, and radioactive compounds. Experimental strategies are discussed for the observation and analysis of the related thermal expansion and magnetostriction of materials, which can achieve a strain sensitivity (ΔL/L) as low as a few parts in one hundred million (≈10 -8). Themore » impact of experimental artifacts, such as those originating in the temperature dependence of the fiber’s index of diffraction, light polarization rotation in magnetic fields, and reduced strain transfer from millimeter-long specimens, is analyzed quantitatively using analytic models available in the literature. We compare the experimental results with model predictions in the small-sample limit, and discuss the uncovered discrepancies.« less

Theory of simultaneous excitonic-superconductivity condensation II Experimental evidence and stoichiometric interpretations

NASA Astrophysics Data System (ADS)

Wong, K. W.; Ching, W. Y.

1989-04-01

We discuss a variety of experimental observations which are consistent with theory of the excitonic-enhancement model (EEM) presented earlier. The experimental works discussed are: (1) isotope substitution; (2) fluorinated YBa 2Cu 3O 7- x; (3) infrared optical spectra; (4) specific heat and tunneling gap; (5) Hall effect and nuclear spin relaxation; (6) positron annihilation; (7) utrasound velocity and sound attenuation; (8) Meissner effect and critical current; (9) antiferromagnetism and oxygen deficiency; (10) flux quantization; and (11) photoemission. A simple stoichiometric interpretation on the existing high temperature superconducting oxides based on the specific stacking of chemical subsystems is also presented. It is argued that according to EEM theory, a superconducting oxide must contain two stable oxides, one having excitonic levels such as Cu 2O; the other having intrinsic hole population at the top of the valence band such as CuO. A systematic search for other potential high Tc compounds is also suggested.

Methodology of Blade Unsteady Pressure Measurement in the NASA Transonic Flutter Cascade

NASA Technical Reports Server (NTRS)

Lepicovsky, J.; McFarland, E. R.; Capece, V. R.; Jett, T. A.; Senyitko, R. G.

2002-01-01

In this report the methodology adopted to measure unsteady pressures on blade surfaces in the NASA Transonic Flutter Cascade under conditions of simulated blade flutter is described. The previous work done in this cascade reported that the oscillating cascade produced waves, which for some interblade phase angles reflected off the wind tunnel walls back into the cascade, interfered with the cascade unsteady aerodynamics, and contaminated the acquired data. To alleviate the problems with data contamination due to the back wall interference, a method of influence coefficients was selected for the future unsteady work in this cascade. In this approach only one blade in the cascade is oscillated at a time. The majority of the report is concerned with the experimental technique used and the experimental data generated in the facility. The report presents a list of all test conditions for the small amplitude of blade oscillations, and shows examples of some of the results achieved. The report does not discuss data analysis procedures like ensemble averaging, frequency analysis, and unsteady blade loading diagrams reconstructed using the influence coefficient method. Finally, the report presents the lessons learned from this phase of the experimental effort, and suggests the improvements and directions of the experimental work for tests to be carried out for large oscillation amplitudes.

SPHERES: Synchronized, Position, Hold, Engage, Reorient, Experimental Satellites: SPHERES/Astrobee Working Group (SAWG)

NASA Technical Reports Server (NTRS)

Benavides, Jose

2017-01-01

SPHERES/Astrobee Working Group (SAWG) Quarterly meeting. Membership includes MIT, FIT, AFS, DARPA, CASIS, SJSU, and NASA (HQ, KSC, JSC, MSFC, and ARC)Face-to-Face, twice a year Purpose: Information sharing across the SPHERES community Program office shares National Lab Facility availability Status of resources (batteries, CO2 tanks, etc.), Overall Calendar (scheduled Test Sessions, up mass return), and Updates on new PD, Investigations, and ISS infrastructure. Provide the SPHERES community (PD, investigators, etc.) with up-to-date information to determine opportunities to use the NL Facility Discuss proposed changes updates to SPHERES Nat Lab which may be required to support a specific activity or research. Discuss specific support requests made to the ISS Office.

LES of propeller crashback

NASA Astrophysics Data System (ADS)

Kumar, Praveen; Mahesh, Krishnan

2014-11-01

Crashback is an operating condition to quickly stop a propelled vehicle, where the propeller is rotated in the reverse direction to yield a negative thrust. In crashback, the freestream interacts with the strong reverse flow from the propeller leading to massive flow separation and highly unsteady loads. We have used Large-Eddy Simulation (LES) in recent years to accurately simulate the flowfield in crashback around a stand-alone open propeller, hull-attached (posterior alone) open propeller and a ducted propeller with stator blades. This talk will discuss our work towards LES of crashback inclusive of the entire hull. The results will be compared to available experimental data, and the flow physics will be discussed. This work is supported by the Office of Naval Research.

Experimental study on a magnetofluid sealing liquid for propeller shaft

NASA Astrophysics Data System (ADS)

Zhao, Chang-Fa; Sun, Rong-Hua; Zheng, Jin-Xing

2003-06-01

The selecting and preparing method of the basic material of magnetic fluid was introduced. By using a chemical method, the magnetic micropowder Fe3O4 was successfully yielded, and an oil-base as a working carrier and dispersing agent was determined. The preparation process of the magnetic fluid and prescription of the oil-base magnetic fluid were discussed. The simulation experimental rig of magnetic fluid sealing for propeller shaft was designed. The sealing ability experiment was conducted and results were analyzed. The pressure of sealing is up to 2 MPa.

Experimental investigation of hypersonic aerodynamics

NASA Technical Reports Server (NTRS)

Heinemann, K.; Intrieri, Peter F.

1987-01-01

An extensive series of ballistic range tests are currently being conducted at the Ames Research Center. These tests are intended to investigate the hypersonic aerodynamic characteristics of two basic configurations, which are: the blunt-cone Galileo probe which is scheduled to be launched in late 1989 and will enter the atmosphere of Jupiter in 1994, and a generic slender cone configuration to provide experimental aerodynamic data including good flow-field definition which computational aerodynamicists could use to validate their computer codes. Some of the results obtained thus far are presented and work for the near future is discussed.

Reproducible model development in the cardiac electrophysiology Web Lab.

PubMed

Daly, Aidan C; Clerx, Michael; Beattie, Kylie A; Cooper, Jonathan; Gavaghan, David J; Mirams, Gary R

2018-05-26

The modelling of the electrophysiology of cardiac cells is one of the most mature areas of systems biology. This extended concentration of research effort brings with it new challenges, foremost among which is that of choosing which of these models is most suitable for addressing a particular scientific question. In a previous paper, we presented our initial work in developing an online resource for the characterisation and comparison of electrophysiological cell models in a wide range of experimental scenarios. In that work, we described how we had developed a novel protocol language that allowed us to separate the details of the mathematical model (the majority of cardiac cell models take the form of ordinary differential equations) from the experimental protocol being simulated. We developed a fully-open online repository (which we termed the Cardiac Electrophysiology Web Lab) which allows users to store and compare the results of applying the same experimental protocol to competing models. In the current paper we describe the most recent and planned extensions of this work, focused on supporting the process of model building from experimental data. We outline the necessary work to develop a machine-readable language to describe the process of inferring parameters from wet lab datasets, and illustrate our approach through a detailed example of fitting a model of the hERG channel using experimental data. We conclude by discussing the future challenges in making further progress in this domain towards our goal of facilitating a fully reproducible approach to the development of cardiac cell models. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Supporting Scientific Experimentation and Reasoning in Young Elementary School Students

NASA Astrophysics Data System (ADS)

Varma, Keisha

2014-06-01

Researchers from multiple perspectives have shown that young students can engage in the scientific reasoning involved in science experimentation. However, there is little research on how well these young students learn in inquiry-based learning environments that focus on using scientific experimentation strategies to learn new scientific information. This work investigates young children's science concept learning via inquiry-based instruction on the thermodynamics system in a developmentally appropriate, technology-supported learning environment. First- and third-grade students participate in three sets of guided experimentation activities that involve using handheld computers to measure change in temperature given different types of insulation materials. Findings from pre- and post-comparisons show that students at both grade levels are able to learn about the thermodynamics system through engaging in the guided experiment activities. The instruction groups outperformed the control groups on multiple measures of thermodynamics knowledge, and the older children outperform the younger children. Knowledge gains are discussed in the context of mental models of the thermodynamics system that include the individual concepts mentioned above and the relationships between them. This work suggests that young students can benefit from science instruction centered on experimentation activities. It shows the benefits of presenting complex scientific information authentic contexts and the importance of providing the necessary scaffolding for meaningful scientific inquiry and experimentation.

Proceedings of Small Power Systems Solar Electric Workshop. Volume 2: Invited papers

NASA Technical Reports Server (NTRS)

Ferber, R. (Editor)

1978-01-01

The focus of this work shop was to present the committment to the development of solar thermal power plants for a variety of applications including utility applications. Workshop activities included panel discussions, formal presentations, small group interactive discussions, question and answer periods, and informal gatherings. Discussion on topics include: (1) solar power technology options; (2) solar thermal power programs currently underway at the DOE, JPL, Electric Power Research Institute (EPRI), and Solar Energy Research Institute (SERI); (3) power options competing with solar; (4) institutional issues; (5) environmental and siting issues; (6) financial issues; (7) energy storage; (8) site requirements for experimental solar installations, and (9) utility planning.

An X-Ray Analysis Database of Photoionization Cross Sections Including Variable Ionization

NASA Technical Reports Server (NTRS)

Wang, Ping; Cohen, David H.; MacFarlane, Joseph J.; Cassinelli, Joseph P.

1997-01-01

Results of research efforts in the following areas are discussed: review of the major theoretical and experimental data of subshell photoionization cross sections and ionization edges of atomic ions to assess the accuracy of the data, and to compile the most reliable of these data in our own database; detailed atomic physics calculations to complement the database for all ions of 17 cosmically abundant elements; reconciling the data from various sources and our own calculations; and fitting cross sections with functional approximations and incorporating these functions into a compact computer code.Also, efforts included adapting an ionization equilibrium code, tabulating results, and incorporating them into the overall program and testing the code (both ionization equilibrium and opacity codes) with existing observational data. The background and scientific applications of this work are discussed. Atomic physics cross section models and calculations are described. Calculation results are compared with available experimental data and other theoretical data. The functional approximations used for fitting cross sections are outlined and applications of the database are discussed.

Kinetic Behaviour of Failure Waves in a Filled Glass

NASA Astrophysics Data System (ADS)

Resnyansky, A. D.; Bourne, N. K.

2007-12-01

Experimental stress and velocity profiles in a lead filled glass demonstrate a pronounced kinetic behaviour for failure waves in the material during shock loading. The present work summarises the experimental proofs of the kinetic behaviour obtained with stress and velocity gauges. The work describes a model for this behaviour employing a kinetic description used earlier for fracture waves in Pyrex glass. This model is part of a family of two-phase, strain-rate sensitive models describing the behaviour of damaged brittle materials. The modelling results describe well both the stress decay of the failure wave precursor in the stress profiles and main pulse attenuation in the velocity profiles. The influences of the kinetic mechanisms and wave interactions within the test assembly on the reduction of this behaviour are discussed.

Windtunnel Rebuilding And Extrapolation To Flight At Transsonic Speed For ExoMars

NASA Astrophysics Data System (ADS)

Fertig, Markus; Neeb, Dominik; Gulhan, Ali

2011-05-01

The static as well as the dynamic behaviour of the EXOMARS vehicle in the transonic velocity regime has been investigated experimentally by the Supersonic and Hypersonic Technology Department of DLR in order to investigate the behaviour prior to parachute opening. Since the experimental work was performed in air, a numerical extrapolation to flight by means of CFD is necessary. At low supersonic speed this extrapolation to flight was performed by the Spacecraft Department of the Institute of Flow Technology of DLR employing the CFD code TAU. Numerical as well as experimental results for the wind tunnel test at Mach 1.2 will be compared and discussed for three different angles of attack.

Experimental and Numerical Study on Supersonic Ejectors Working with R-1234ze(E)

NASA Astrophysics Data System (ADS)

Kracik, Jan; Dvorak, Vaclav; Nguyen Van, Vu; Smierciew, Kamil

2018-06-01

These days, much effort is being put into lowering the consumption of electric energy and involving renewable energy sources. Many engineers and designers are trying to develop environment-friendly technologies worldwide. It is related to incorporating appropriate devices into such technologies. The object of this paper is to investigate these devices in connection with refrigeration systems. Ejectors can be considered such as these devices. The primary interest of this paper is to investigate the suitability of a numerical model for an ejector, which is incorporated into a refrigeration system. In the present paper, there have been investigated seven different test runs of working of the ejector with a working fluid R-1234ze(E). Some of the investigated cases seem to have a good agreement and there are no significant discrepancies between them, however, there are also cases that do not correspond to the experimental data at all. The ejector has been investigated in both on-design and off-design working modes. A comparison between the experimental and numerical data (CFD) performed by Ansys Fluent software is presented and discussed for both an ideal and a real gas model. In addition, an enhanced analytical model has been introduced for all runs of the ejector.

Designing and Implementing an "Intelligent" Multimedia Tutoring System for Repair Tasks: Final Report.

ERIC Educational Resources Information Center

Baggett, Patricia

1989-01-01

The first part of this document is the final report of a research project (1984-1989) on designing and implementing an intelligent multimedia tutoring system for repair tasks. The problem/goal and approach, equipment and implementation, experimental work, and results are discussed for three phases of research: (1) developing and testing an…

Analysis of short pulse laser altimetry data obtained over horizontal path

NASA Technical Reports Server (NTRS)

Im, K. E.; Tsai, B. M.; Gardner, C. S.

1983-01-01

Recent pulsed measurements of atmospheric delay obtained by ranging to the more realistic targets including a simulated ocean target and an extended plate target are discussed. These measurements are used to estimate the expected timing accuracy of a correlation receiver system. The experimental work was conducted using a pulsed two color laser altimeter.

Anisotropy of machine building materials

NASA Technical Reports Server (NTRS)

Ashkenazi, Y. K.

1981-01-01

The results of experimental studies of the anisotropy of elastic and strength characteristics of various structural materials, including pressure worked metals and alloys, laminated fiberglass plastics, and laminated wood plastics, are correlated and classified. Strength criteria under simple and complex stresses are considered as applied to anisotropic materials. Practical application to determining the strength of machine parts and structural materials is discussed.

NASA's Student Glovebox: An Inquiry-Based Technology Educator's Guide.

ERIC Educational Resources Information Center

Rosenberg, Carla B.; Rogers, Melissa J. B.

This inquiry-based activity discusses the development of a glovebox like those used on the International Space Station and Space Shuttle. A glovebox is a box used for experimentation in which the user inserts hands into gloved access holes in order to work in the box. Activities concerning the study of liquid droplets are included to give students…

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

Philippe, Sebastien

A system that can compare physical objects while potentially protecting sensitive information about the objects themselves has been demonstrated experimentally at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL). This work, by researchers at Princeton University and PPPL, marks an initial confirmation of the application of a powerful cryptographic technique in the physical world. Graduate student Sébastien Philippe discusses the experiment.

Running wheel training does not change neurogenesis levels or alter working memory tasks in adult rats

PubMed Central

Rojas, Manuel J.; Cardenas P., Fernando

2017-01-01

Background Exercise can change cellular structure and connectivity (neurogenesis or synaptogenesis), causing alterations in both behavior and working memory. The aim of this study was to evaluate the effect of exercise on working memory and hippocampal neurogenesis in adult male Wistar rats using a T-maze test. Methods An experimental design with two groups was developed: the experimental group (n = 12) was subject to a forced exercise program for five days, whereas the control group (n = 9) stayed in the home cage. Six to eight weeks after training, the rats’ working memory was evaluated in a T-maze test and four choice days were analyzed, taking into account alternation as a working memory indicator. Hippocampal neurogenesis was evaluated by means of immunohistochemistry of BrdU positive cells. Results No differences between groups were found in the behavioral variables (alternation, preference index, time of response, time of trial or feeding), or in the levels of BrdU positive cells. Discussion Results suggest that although exercise may have effects on brain structure, a construct such as working memory may require more complex changes in networks or connections to demonstrate a change at behavioral level. PMID:28503368

The impact of genetically modified crops on soil microbial communities.

PubMed

Giovannetti, Manuela; Sbrana, Cristiana; Turrini, Alessandra

2005-01-01

Genetically modified (GM) plants represent a potential benefit for environmentally friendly agriculture and human health. Though, poor knowledge is available on potential hazards posed by unintended modifications occurring during genetic manipulation. The increasing amount of reports on ecological risks and benefits of GM plants stresses the need for experimental works aimed at evaluating the impact of GM crops on natural and agro-ecosystems. Major environmental risks associated with GM crops include their potential impact on non-target soil microorganisms playing a fundamental role in crop residues degradation and in biogeochemical cycles. Recent works assessed the effects of GM crops on soil microbial communities on the basis of case-by-case studies, using multimodal experimental approaches involving different target and non-target organisms. Experimental evidences discussed in this review confirm that a precautionary approach should be adopted, by taking into account the risks associated with the unpredictability of transformation events, of their pleiotropic effects and of the fate of transgenes in natural and agro-ecosystems, weighing benefits against costs.

Positron-annihilation 2D-ACAR studies of disordered and defected alloys

NASA Astrophysics Data System (ADS)

Bansil, A.; Prasad, R.; Smedskjaer, L. C.; Benedek, R.; Mijnarends, P. E.

1987-09-01

Theoretical and experimental progess in connection with 2D-ACAR positron annihilation studies of ordered, disordered, and defected alloys is discussed. We present, in particular, some of the recent developments concerning the electronic structure of disordered alloys, and the work in the area of annihilation from positrons trapped at vacancy-type defects in metals and alloys. The electronic structure and properties of a number of compounds are also discussed briefly; we comment specifically on high T sub c ceramic superconductors, Heusler alloys, and transition-metal aluminides.

Shedding light on the puzzle of drug-membrane interactions: Experimental techniques and molecular dynamics simulations.

PubMed

Lopes, Daniela; Jakobtorweihen, Sven; Nunes, Cláudia; Sarmento, Bruno; Reis, Salette

2017-01-01

Lipid membranes work as barriers, which leads to inevitable drug-membrane interactions in vivo. These interactions affect the pharmacokinetic properties of drugs, such as their diffusion, transport, distribution, and accumulation inside the membrane. Furthermore, these interactions also affect their pharmacodynamic properties with respect to both therapeutic and toxic effects. Experimental membrane models have been used to perform in vitro assessment of the effects of drugs on the biophysical properties of membranes by employing different experimental techniques. In in silico studies, molecular dynamics simulations have been used to provide new insights at an atomistic level, which enables the study of properties that are difficult or even impossible to measure experimentally. Each model and technique has its advantages and disadvantages. Hence, combining different models and techniques is necessary for a more reliable study. In this review, the theoretical backgrounds of these (in vitro and in silico) approaches are presented, followed by a discussion of the pharmacokinetic and pharmacodynamic properties of drugs that are related to their interactions with membranes. All approaches are discussed in parallel to present for a better connection between experimental and simulation studies. Finally, an overview of the molecular dynamics simulation studies used for drug-membrane interactions is provided. Copyright © 2016 Elsevier Ltd. All rights reserved.

Computational Biochemistry-Enzyme Mechanisms Explored.

PubMed

Culka, Martin; Gisdon, Florian J; Ullmann, G Matthias

2017-01-01

Understanding enzyme mechanisms is a major task to achieve in order to comprehend how living cells work. Recent advances in biomolecular research provide huge amount of data on enzyme kinetics and structure. The analysis of diverse experimental results and their combination into an overall picture is, however, often challenging. Microscopic details of the enzymatic processes are often anticipated based on several hints from macroscopic experimental data. Computational biochemistry aims at creation of a computational model of an enzyme in order to explain microscopic details of the catalytic process and reproduce or predict macroscopic experimental findings. Results of such computations are in part complementary to experimental data and provide an explanation of a biochemical process at the microscopic level. In order to evaluate the mechanism of an enzyme, a structural model is constructed which can be analyzed by several theoretical approaches. Several simulation methods can and should be combined to get a reliable picture of the process of interest. Furthermore, abstract models of biological systems can be constructed combining computational and experimental data. In this review, we discuss structural computational models of enzymatic systems. We first discuss various models to simulate enzyme catalysis. Furthermore, we review various approaches how to characterize the enzyme mechanism both qualitatively and quantitatively using different modeling approaches. © 2017 Elsevier Inc. All rights reserved.

Oxygen demand of perfused heart preparations: how electromechanical function and inadequate oxygenation affect physiology and optical measurements.

PubMed

Kuzmiak-Glancy, Sarah; Jaimes, Rafael; Wengrowski, Anastasia M; Kay, Matthew W

2015-06-01

What is the topic of this review? This review discusses how the function and electrophysiology of isolated perfused hearts are affected by oxygenation and energy utilization. The impact of oxygenation on fluorescence measurements in perfused hearts is also discussed. What advances does it highlight? Recent studies have illuminated the inherent differences in electromechanical function, energy utilization rate and oxygen requirements between the primary types of excised heart preparations. A summary and analysis of how these variables affect experimental results are necessary to elevate the physiological relevance of these approaches in order to advance the field of whole-heart research. The ex vivo perfused heart recreates important aspects of in vivo conditions to provide insight into whole-organ function. In this review we discuss multiple types of ex vivo heart preparations, explain how closely each mimic in vivo function, and discuss how changes in electromechanical function and inadequate oxygenation of ex vivo perfused hearts may affect measurements of physiology. Hearts that perform physiological work have high oxygen demand and are likely to experience hypoxia when perfused with a crystalloid perfusate. Adequate myocardial oxygenation is critically important for obtaining physiologically relevant measurements, so when designing experiments the type of ex vivo preparation and the capacity of perfusate to deliver oxygen must be carefully considered. When workload is low, such as during interventions that inhibit contraction, oxygen demand is also low, which could dramatically alter a physiological response to experimental variables. Changes in oxygenation also alter the optical properties of cardiac tissue, an effect that may influence optical signals measured from both endogenous and exogenous fluorophores. Careful consideration of oxygen supply, working condition, and wavelengths used to acquire optical signals is critical for obtaining physiologically relevant measurements during ex vivo perfused heart studies. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.

Faculty Member for Research in an Undergraduate Institution Prize Talk: Research and Teaching through high-precision spectroscopy of heavy atoms

NASA Astrophysics Data System (ADS)

Majumder, Tiku

2017-04-01

In recent decades, substantial experimental effort has centered on heavy (high-Z) atomic and molecular systems for atomic-physics-based tests of standard model physics, through (for example) measurements of atomic parity nonconservation and searches for permanent electric dipole moments. In all of this work, a crucial role is played by atomic theorists, whose accurate wave function calculations are essential in connecting experimental observables to tests of relevant fundamental physics parameters. At Williams College, with essential contributions from dozens of undergraduate students, we have pursued a series of precise atomic structure measurements in heavy metal atoms such as thallium, indium, and lead. These include measurements of hyperfine structure, transition amplitudes, and atomic polarizability. This work, involving diode lasers, heated vapor cells, and an atomic beam apparatus, has both tested the accuracy and helped guide the refinement of new atomic theory calculations. I will discuss a number of our recent experimental results, emphasizing the role played by students and the opportunities that have been afforded for research-training in this undergraduate environment. Work supported by Research Corporation, the NIST Precision Measurement Grants program, and the National Science Foundation.

Cancer in light of experimental evolution.

PubMed

Sprouffske, Kathleen; Merlo, Lauren M F; Gerrish, Philip J; Maley, Carlo C; Sniegowski, Paul D

2012-09-11

Cancer initiation, progression, and the emergence of therapeutic resistance are evolutionary phenomena of clonal somatic cell populations. Studies in microbial experimental evolution and the theoretical work inspired by such studies are yielding deep insights into the evolutionary dynamics of clonal populations, yet there has been little explicit consideration of the relevance of this rapidly growing field to cancer biology. Here, we examine how the understanding of mutation, selection, and spatial structure in clonal populations that is emerging from experimental evolution may be applicable to cancer. Along the way, we discuss some significant ways in which cancer differs from the model systems used in experimental evolution. Despite these differences, we argue that enhanced prediction and control of cancer may be possible using ideas developed in the context of experimental evolution, and we point out some prospects for future research at the interface between these traditionally separate areas. Copyright © 2012 Elsevier Ltd. All rights reserved.

Improvements of the target lifetime in the RHIC polarimeter

NASA Astrophysics Data System (ADS)

Steski, D. B.; Huang, H.; Kewisch, J.; Sukhanova, L.; Zelenski, A.

2018-05-01

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) is the only collider in the world to collide polarized protons. It is critical to the RHIC experimental program that the polarization of the proton beam is measured. This is accomplished with the Coulomb Nuclear Interference (CNI) polarimeter. The targets used in the RHIC CNI polarimeter are 50 nm thick, 25 mm long and <10 µm wide. As the beam intensity in RHIC has increased and the beam size has decreased, the lifetime of these targets has decreased dramatically. During the 2013 polarized proton experimental run, the targets needed to be replaced twice. This resulted in additional work and lost beam time. Before the 2015 experimental run, metal shields were installed around the ends of the targets which greatly improved the target lifetime. The results from the 2015 experimental run and plans for the 2017 experimental run will be discussed.

Cancer in Light of Experimental Evolution

PubMed Central

Sprouffske, Kathleen; Merlo, Lauren M.F.; Gerrish, Philip J.; Maley, Carlo C.; Sniegowski, Paul D.

2012-01-01

Cancer initiation, progression, and the emergence of therapeutic resistance are evolutionary phenomena of clonal somatic cell populations. Studies in microbial experimental evolution and the theoretical work inspired by such studies are yielding deep insights into the evolutionary dynamics of clonal populations, yet there has been little explicit consideration of the relevance of this rapidly growing field to cancer biology. Here, we examine how the understanding of mutation, selection, and spatial structure in clonal populations that is emerging from experimental evolution may be applicable to cancer. Along the way, we discuss some significant ways in which cancer differs from the model systems used in experimental evolution. Despite these differences, we argue that enhanced prediction and control of cancer may be possible using ideas developed in the context of experimental evolution, and we point out some prospects for future research at the interface between these traditionally separate areas. PMID:22975007

Quantum-Like Representation of Non-Bayesian Inference

NASA Astrophysics Data System (ADS)

Asano, M.; Basieva, I.; Khrennikov, A.; Ohya, M.; Tanaka, Y.

2013-01-01

This research is related to the problem of "irrational decision making or inference" that have been discussed in cognitive psychology. There are some experimental studies, and these statistical data cannot be described by classical probability theory. The process of decision making generating these data cannot be reduced to the classical Bayesian inference. For this problem, a number of quantum-like coginitive models of decision making was proposed. Our previous work represented in a natural way the classical Bayesian inference in the frame work of quantum mechanics. By using this representation, in this paper, we try to discuss the non-Bayesian (irrational) inference that is biased by effects like the quantum interference. Further, we describe "psychological factor" disturbing "rationality" as an "environment" correlating with the "main system" of usual Bayesian inference.

Measuring reinforcement learning and motivation constructs in experimental animals: relevance to the negative symptoms of schizophrenia.

PubMed

Markou, Athina; Salamone, John D; Bussey, Timothy J; Mar, Adam C; Brunner, Daniela; Gilmour, Gary; Balsam, Peter

2013-11-01

The present review article summarizes and expands upon the discussions that were initiated during a meeting of the Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia (CNTRICS; http://cntrics.ucdavis.edu) meeting. A major goal of the CNTRICS meeting was to identify experimental procedures and measures that can be used in laboratory animals to assess psychological constructs that are related to the psychopathology of schizophrenia. The issues discussed in this review reflect the deliberations of the Motivation Working Group of the CNTRICS meeting, which included most of the authors of this article as well as additional participants. After receiving task nominations from the general research community, this working group was asked to identify experimental procedures in laboratory animals that can assess aspects of reinforcement learning and motivation that may be relevant for research on the negative symptoms of schizophrenia, as well as other disorders characterized by deficits in reinforcement learning and motivation. The tasks described here that assess reinforcement learning are the Autoshaping Task, Probabilistic Reward Learning Tasks, and the Response Bias Probabilistic Reward Task. The tasks described here that assess motivation are Outcome Devaluation and Contingency Degradation Tasks and Effort-Based Tasks. In addition to describing such methods and procedures, the present article provides a working vocabulary for research and theory in this field, as well as an industry perspective about how such tasks may be used in drug discovery. It is hoped that this review can aid investigators who are conducting research in this complex area, promote translational studies by highlighting shared research goals and fostering a common vocabulary across basic and clinical fields, and facilitate the development of medications for the treatment of symptoms mediated by reinforcement learning and motivational deficits. Copyright © 2013 Elsevier Ltd. All rights reserved.

Measuring reinforcement learning and motivation constructs in experimental animals: relevance to the negative symptoms of schizophrenia

PubMed Central

Markou, Athina; Salamone, John D.; Bussey, Timothy; Mar, Adam; Brunner, Daniela; Gilmour, Gary; Balsam, Peter

2013-01-01

The present review article summarizes and expands upon the discussions that were initiated during a meeting of the Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia (CNTRICS; http://cntrics.ucdavis.edu). A major goal of the CNTRICS meeting was to identify experimental procedures and measures that can be used in laboratory animals to assess psychological constructs that are related to the psychopathology of schizophrenia. The issues discussed in this review reflect the deliberations of the Motivation Working Group of the CNTRICS meeting, which included most of the authors of this article as well as additional participants. After receiving task nominations from the general research community, this working group was asked to identify experimental procedures in laboratory animals that can assess aspects of reinforcement learning and motivation that may be relevant for research on the negative symptoms of schizophrenia, as well as other disorders characterized by deficits in reinforcement learning and motivation. The tasks described here that assess reinforcement learning are the Autoshaping Task, Probabilistic Reward Learning Tasks, and the Response Bias Probabilistic Reward Task. The tasks described here that assess motivation are Outcome Devaluation and Contingency Degradation Tasks and Effort-Based Tasks. In addition to describing such methods and procedures, the present article provides a working vocabulary for research and theory in this field, as well as an industry perspective about how such tasks may be used in drug discovery. It is hoped that this review can aid investigators who are conducting research in this complex area, promote translational studies by highlighting shared research goals and fostering a common vocabulary across basic and clinical fields, and facilitate the development of medications for the treatment of symptoms mediated by reinforcement learning and motivational deficits. PMID:23994273

Recent radial turbine research at the NASA Lewis Research Center.

NASA Technical Reports Server (NTRS)

Rohlik, H. E.; Kofskey, M. G.

1972-01-01

The major results obtained in several recent experimental programs on small radial inflow turbines for space applications are presented and discussed. Specifically, experimental and analytical work associated with these systems that has included examination of blade-shroud clearance, blade loading, and exit diffuser design, is considered. Results indicate high efficiency over a wide range of specific speed, and also insensitivity to clearance and blade loading in the radial part of the rotor. The exit diffuser investigation indicated that a conventional conical outer wall may not provide the velocity variation consistent with minimum overall diffuser loss.

Quiet Clean Short-Haul Experimental Engine (QCSEE): Acoustic treatment development and design

NASA Technical Reports Server (NTRS)

Clemons, A.

1979-01-01

Acoustic treatment designs for the quiet clean short-haul experimental engines are defined. The procedures used in the development of each noise-source suppressor device are presented and discussed in detail. A complete description of all treatment concepts considered and the test facilities utilized in obtaining background data used in treatment development are also described. Additional supporting investigations that are complementary to the treatment development work are presented. The expected suppression results for each treatment configuration are given in terms of delta SPL versus frequency and in terms of delta PNdB.

Research on grid connection control technology of double fed wind generator

NASA Astrophysics Data System (ADS)

Ling, Li

2017-01-01

The composition and working principle of variable speed constant frequency doubly fed wind power generation system is discussed in this thesis. On the basis of theoretical analysis and control on the modeling, the doubly fed wind power generation simulation control system is designed based on a TMS320F2407 digital signal processor (DSP), and has done a large amount of experimental research, which mainly include, variable speed constant frequency, constant pressure, Grid connected control experiment. The running results show that the design of simulation control system is reasonable and can meet the need of experimental research.

Absolute rate of the reaction of C l(2P) with methane from 200-500 K

NASA Technical Reports Server (NTRS)

Whytock, D. A.; Lee, J. H.; Michael, J. V.; Payne, W. A.; Stief, L. J.

1976-01-01

Rate constants for the reaction of atomic chlorine with methane have been measured from 200-500K using the flash photolysis-resonance fluorescence technique. When the results from fourteen equally spaced experimental determinations are plotted in Arrhenius form a definite curvature is noted. The results are compared to previous work and are theoretically discussed.

The Path of Carbon in Photosynthesis VI.

DOE R&D Accomplishments Database

Calvin, M.

1949-06-30

This paper is a compilation of the essential results of our experimental work in the determination of the path of carbon in photosynthesis. There are discussions of the dark fixation of photosynthesis and methods of separation and identification including paper chromatography and radioautography. The definition of the path of carbon in photosynthesis by the distribution of radioactivity within the compounds is described.

The Use and Benefits of Computer Aided Learning in the Assessment of the Laboratory Exercise "Enzyme Induction in Escherichia coli".

ERIC Educational Resources Information Center

Pamula, F.; And Others

1995-01-01

Describes an interactive computer program written to provide accurate and immediate feedback to students while they are processing experimental data. Discusses the problems inherent in laboratory courses that led to the development of this program. Advantages of the software include allowing students to work at their own pace in a nonthreatening…

From a Post-Traumatic Culture toward the Cultural Trauma of Post-9/11

ERIC Educational Resources Information Center

Jabarouti, Roya; Mani, ManiMangai

2014-01-01

Over the past decade, the impact of the terroristic attacks of September 11, 2001 on American culture has been the prominent subject of various discussions. This has led to a large body of theoretical and experimental works known as "post-9/11", which provides evidence for what Smelser's believes to be the cultural trauma of 9/11. This…

Theoretical models of helicopter rotor noise

NASA Technical Reports Server (NTRS)

Hawkings, D. L.

1978-01-01

For low speed rotors, it is shown that unsteady load models are only partially successful in predicting experimental levels. A theoretical model is presented which leads to the concept of unsteady thickness noise. This gives better agreement with test results. For high speed rotors, it is argued that present models are incomplete and that other mechanisms are at work. Some possibilities are briefly discussed.

Effects of Thermal Cycling on Control and Irradiated EPC 2nd Generation GaN FETs

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Scheick, Leif; Lauenstein, Jean-Marie; Casey, Megan; Hammoud, Ahmad

2013-01-01

The power systems for use in NASA space missions must work reliably under harsh conditions including radiation, thermal cycling, and exposure to extreme temperatures. Gallium nitride semiconductors show great promise, but information pertaining to their performance is scarce. Gallium nitride N-channel enhancement-mode field effect transistors made by EPC Corporation in a 2nd generation of manufacturing were exposed to radiation followed by long-term thermal cycling in order to address their reliability for use in space missions. Results of the experimental work are presented and discussed.

Feasibility of MHD submarine propulsion. Phase II, MHD propulsion: Testing in a two Tesla test facility

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

Doss, E.D.; Sikes, W.C.

1992-09-01

This report describes the work performed during Phase 1 and Phase 2 of the collaborative research program established between Argonne National Laboratory (ANL) and Newport News Shipbuilding and Dry Dock Company (NNS). Phase I of the program focused on the development of computer models for Magnetohydrodynamic (MHD) propulsion. Phase 2 focused on the experimental validation of the thruster performance models and the identification, through testing, of any phenomena which may impact the attractiveness of this propulsion system for shipboard applications. The report discusses in detail the work performed in Phase 2 of the program. In Phase 2, a two Teslamore » test facility was designed, built, and operated. The facility test loop, its components, and their design are presented. The test matrix and its rationale are discussed. Representative experimental results of the test program are presented, and are compared to computer model predictions. In general, the results of the tests and their comparison with the predictions indicate that thephenomena affecting the performance of MHD seawater thrusters are well understood and can be accurately predicted with the developed thruster computer models.« less

Neighborhoods and health: where are we and were do we go from here?

PubMed Central

DIEZ-ROUX, A. V.

2007-01-01

Summary In recent years there has been an explosion of interest in neighborhood health effects. Most existing work has relied on secondary data analyses and has used administrative areas and aggregate census data to characterize neighborhoods. Important questions remain regarding whether the associations reported by these studies reflect causal processes. This paper reviews the major limitations of existing work and discusses areas for future development including (1) definition and measurement of area or ecologic attributes (2) consideration of spatial scale (3) cumulative exposures and lagged effects and (4) the complementary nature of observational, quasi-experimental, and experimental evidence. As is usually the case with complex research questions, consensus regarding the presence and magnitude of neighborhood health effects will emerge from the work of multiple disciplines, often with diverse methodological approaches, each with its strengths and its limitations. Partnership across disciplines, as well as among health researchers, communities, urban planners, and policy experts will be key. PMID:17320330

How to Study Thermal Applications of Open-Cell Metal Foam: Experiments and Computational Fluid Dynamics

PubMed Central

De Schampheleire, Sven; De Jaeger, Peter; De Kerpel, Kathleen; Ameel, Bernd; Huisseune, Henk; De Paepe, Michel

2016-01-01

This paper reviews the available methods to study thermal applications with open-cell metal foam. Both experimental and numerical work are discussed. For experimental research, the focus of this review is on the repeatability of the results. This is a major concern, as most studies only report the dependence of thermal properties on porosity and a number of pores per linear inch (PPI-value). A different approach, which is studied in this paper, is to characterize the foam using micro tomography scans with small voxel sizes. The results of these scans are compared to correlations from the open literature. Large differences are observed. For the numerical work, the focus is on studies using computational fluid dynamics. A novel way of determining the closure terms is proposed in this work. This is done through a numerical foam model based on micro tomography scan data. With this foam model, the closure terms are determined numerically. PMID:28787894

Experimental Study and Optimization of Thermoelectricity-Driven Autonomous Sensors for the Chimney of a Biomass Power Plant

NASA Astrophysics Data System (ADS)

Rodríguez, A.; Astrain, D.; Martínez, A.; Aranguren, P.

2014-06-01

In the work discussed in this paper a thermoelectric generator was developed to harness waste heat from the exhaust gas of a boiler in a biomass power plant and thus generate electric power to operate a flowmeter installed in the chimney, to make it autonomous. The main objective was to conduct an experimental study to optimize a previous design obtained after computational work based on a simulation model for thermoelectric generators. First, several places inside and outside the chimney were considered as sites for the thermoelectricity-driven autonomous sensor. Second, the thermoelectric generator was built and tested to assess the effect of the cold-side heat exchanger on the electric power, power consumption by the flowmeter, and transmission frequency. These tests provided the best configuration for the heat exchanger, which met the transmission requirements for different working conditions. The final design is able to transmit every second and requires neither batteries nor electric wires. It is a promising application in the field of thermoelectric generation.

Theoretical and experimental study on electron interactions with chlorobenzene: Shape resonances and differential cross sections

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

Barbosa, Alessandra Souza; Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica; Varella, Márcio T. do N.

2016-08-28

In this work, we report theoretical and experimental cross sections for elastic scattering of electrons by chlorobenzene (ClB). The theoretical integral and differential cross sections (DCSs) were obtained with the Schwinger multichannel method implemented with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR). The calculations with the SMCPP method were done in the static-exchange (SE) approximation, for energies above 12 eV, and in the static-exchange plus polarization approximation, for energies up to 12 eV. The calculations with the IAM-SCAR method covered energies up to 500 eV. The experimental differential cross sections were obtained in themore » high resolution electron energy loss spectrometer VG-SEELS 400, in Lisbon, for electron energies from 8.0 eV to 50 eV and angular range from 7{sup ∘} to 110{sup ∘}. From the present theoretical integral cross section (ICS) we discuss the low-energy shape-resonances present in chlorobenzene and compare our computed resonance spectra with available electron transmission spectroscopy data present in the literature. Since there is no other work in the literature reporting differential cross sections for this molecule, we compare our theoretical and experimental DCSs with experimental data available for the parent molecule benzene.« less

An experimental study of a turbulent boundary layer in the trailing edge region of a circulation-control airfoil

NASA Technical Reports Server (NTRS)

Heinemann, K.; Brown, Jeff

1992-01-01

This report discusses progress made on NASA Cooperative Agreement NCC2-545, 'An Experimental Study of a Turbulent Boundary Layer in the Trailing-Edge Region of a Circulation-Control Airfoil' during the period 9/1/91 through 9/30/92. The study features 2-component laser Doppler velocimeter (LDV) measurements in the trailing edge and wake regions of a generic 2-dimensional circulation-control model. The final experimental phase of the study will be carried out in the Ames High Reynolds Number Channel 2 (HRC2) transonic blow-down-facility. During the 13-month period covered by this report, work continued on the development of the near-wall laser Doppler velocimeter (LDV) described in previous reports.

Experimental confirmation of a PDE-based approach to design of feedback controls

NASA Technical Reports Server (NTRS)

Banks, H. T.; Smith, Ralph C.; Brown, D. E.; Silcox, R. J.; Metcalf, Vern L.

1995-01-01

Issues regarding the experimental implementation of partial differential equation based controllers are discussed in this work. While the motivating application involves the reduction of vibration levels for a circular plate through excitation of surface-mounted piezoceramic patches, the general techniques described here will extend to a variety of applications. The initial step is the development of a PDE model which accurately captures the physics of the underlying process. This model is then discretized to yield a vector-valued initial value problem. Optimal control theory is used to determine continuous-time voltages to the patches, and the approximations needed to facilitate discrete time implementation are addressed. Finally, experimental results demonstrating the control of both transient and steady state vibrations through these techniques are presented.

Characterizing new compositions of [001]C relaxor ferroelectric single crystals using a work-energy model

NASA Astrophysics Data System (ADS)

Gallagher, John A.

2016-04-01

The desired operating range of ferroelectric materials with compositions near the morphotropic phase boundary is limited by field induced phase transformations. In [001]C cut and poled relaxor ferroelectric single crystals the mechanically driven ferroelectric rhombohedral to ferroelectric orthorhombic phase transformation is hindered by antagonistic electrical loading. Instability around the phase transformation makes the current experimental technique for characterization of the large field behavior very time consuming. Characterization requires specialized equipment and involves an extensive set of measurements under combined electrical, mechanical, and thermal loads. In this work a mechanism-based model is combined with a more limited set of experiments to obtain the same results. The model utilizes a work-energy criterion that calculates the mechanical work required to induce the transformation and the required electrical work that is removed to reverse the transformation. This is done by defining energy barriers to the transformation. The results of the combined experiment and modeling approach are compared to the fully experimental approach and error is discussed. The model shows excellent predictive capability and is used to substantially reduce the total number of experiments required for characterization. This decreases the time and resources required for characterization of new compositions.

Los Alamos Science: The Human Genome Project. Number 20, 1992

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

Cooper, N G; Shea, N

1992-01-01

This article provides a broad overview of the Human Genome Project, with particular emphasis on work being done at Los Alamos. It tries to emphasize the scientific aspects of the project, compared to the more speculative information presented in the popular press. There is a brief introduction to modern genetics, including a review of classic work. There is a broad overview of the Genome Project, describing what the project is, what are some of its major five-year goals, what are major technological challenges ahead of the project, and what can the field of biology, as well as society expect tomore » see as benefits from this project. Specific results on the efforts directed at mapping chromosomes 16 and 5 are discussed. A brief introduction to DNA libraries is presented, bearing in mind that Los Alamos has housed such libraries for many years prior to the Genome Project. Information on efforts to do applied computational work related to the project are discussed, as well as experimental efforts to do rapid DNA sequencing by means of single-molecule detection using applied spectroscopic methods. The article introduces the Los Alamos staff which are working on the Genome Project, and concludes with brief discussions on ethical, legal, and social implications of this work; a brief glimpse of genetics as it may be practiced in the next century; and a glossary of relevant terms.« less

Los Alamos Science: The Human Genome Project. Number 20, 1992

DOE R&D Accomplishments Database

Cooper, N. G.; Shea, N. eds.

1992-01-01

This document provides a broad overview of the Human Genome Project, with particular emphasis on work being done at Los Alamos. It tries to emphasize the scientific aspects of the project, compared to the more speculative information presented in the popular press. There is a brief introduction to modern genetics, including a review of classic work. There is a broad overview of the Genome Project, describing what the project is, what are some of its major five-year goals, what are major technological challenges ahead of the project, and what can the field of biology, as well as society expect to see as benefits from this project. Specific results on the efforts directed at mapping chromosomes 16 and 5 are discussed. A brief introduction to DNA libraries is presented, bearing in mind that Los Alamos has housed such libraries for many years prior to the Genome Project. Information on efforts to do applied computational work related to the project are discussed, as well as experimental efforts to do rapid DNA sequencing by means of single-molecule detection using applied spectroscopic methods. The article introduces the Los Alamos staff which are working on the Genome Project, and concludes with brief discussions on ethical, legal, and social implications of this work; a brief glimpse of genetics as it may be practiced in the next century; and a glossary of relevant terms.

Neutron scattering studies of the RENi 2B 2C (RE = Lu, Y, Ho, Er): Lattice dynamics

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

Bullock, Max

1998-02-23

The first chapter gives a brief overview of the system discussed in this dissertation. Chapters 2-5 and Appendix B of this dissertation consist of papers that are published, or have been submitted, which show experimental data regarding the phonon softening of LuNi 2B 2C. These papers have been removed and processed separately. Chapter 6 will contain a summary of the conclusions up to date. Appendix A will consist of a brief derivation of χ(q) which is talked about in the introduction of the dissertation. Appendix B will contain a Born-von Karman model fit to the experimental LuNi 2B 2C datamore » and a comparison with experimental data. Appendix C will contain a brief summary of the work done on LuNi 2B 2C as well as a complete listing of experimental data taken on the crystals which may be needed later for theoretical models of this system. Appendix D will outline a brief introduction covering some of the field theory used in the theoretical work for this thesis.« less

Quantum memories with zero-energy Majorana modes and experimental constraints

NASA Astrophysics Data System (ADS)

Ippoliti, Matteo; Rizzi, Matteo; Giovannetti, Vittorio; Mazza, Leonardo

2016-06-01

In this work we address the problem of realizing a reliable quantum memory based on zero-energy Majorana modes in the presence of experimental constraints on the operations aimed at recovering the information. In particular, we characterize the best recovery operation acting only on the zero-energy Majorana modes and the memory fidelity that can be therewith achieved. In order to understand the effect of such restriction, we discuss two examples of noise models acting on the topological system and compare the amount of information that can be recovered by accessing either the whole system, or the zero modes only, with particular attention to the scaling with the size of the system and the energy gap. We explicitly discuss the case of a thermal bosonic environment inducing a parity-preserving Markovian dynamics in which the memory fidelity achievable via a read-out of the zero modes decays exponentially in time, independent from system size. We argue, however, that even in the presence of said experimental limitations, the Hamiltonian gap is still beneficial to the storage of information.

Experimental Investigations And Numerical Modelling of 210CR12 Steel in Semi-Solid State

NASA Astrophysics Data System (ADS)

Macioł, Piotr; Zalecki, Władysław; Kuziak, Roman; Jakubowicz, Aleksandra; Weglarczyk, Stanisław

2011-05-01

Experimental investigation, including hot compression and simple closed die filling was performed. Temperature range of tests was between 1225 °C and 1320 °C. Temperature selection was adequate with liquid fraction between 20 and 60%, which is typical for thixoforming processes. In the die filling test, steel dies with ceramic layer was used (highly refractory air-setting mortar JM 3300 manufactured by Thermal Ceramics). Experiments were carried out on the Gleeble 3800 physical simulator with MCU unit. In the paper, methodology of experimental investigation is described. Dependency of forming forces on temperature and forming velocities is analysed. Obtained results are discussed. The second part of the paper concerns numerical modelling of semi-solid forming. Numerical models for both sets of test were developed. Structural and Computational Fluid Dynamics models are compared. Initial works in microstructural modelling of 210CR12 steel behaviour are described. Lattice Boltzman Method model for thixotropic flows is introduced. Microscale and macroscale models were integrated into multiscale simulation of semi-solid forming. Some fundamental issues related to multiscale modelling of thixoforming are discussed.

What Skills Should Students of Undergraduate Biochemistry and Molecular Biology Programs Have Upon Graduation?

PubMed Central

White, Harold B.; Benore, Marilee A.; Sumter, Takita F.; Caldwell, Benjamin D.; Bell, Ellis

2014-01-01

Biochemistry and molecular biology (BMB) students should demonstrate proficiency in the foundational concepts of the discipline and possess the skills needed to practice as professionals. To ascertain the skills that should be required, groups of BMB educators met in several focused workshops to discuss the expectations with the ultimate goal of clearly articulating the skills required. The results of these discussions highlight the critical importance of experimental, mathematical, and interpersonal skills including collaboration, teamwork, safety, and ethics. The groups also found experimental design, data interpretation and analysiand the ability to communicate findings to diverse audience to be essential skills. To aid in the development of appropriate assessments these skills are grouped into three categories, 1) Process of Science, 2) Communication and Comprehension of Science, and 3) Community of Practice Aspects of Science. Finally, the groups worked to align these competencies with the best practices in both teaching and in skills assessment. PMID:24019246

STOL propulsion systems

NASA Technical Reports Server (NTRS)

Denington, R. J.; Koenig, R. W.; Vanco, M. R.; Sagerser, D. A.

1972-01-01

The selection and the characteristics of quiet, clean propulsion systems for STOL aircraft are discussed. Engines are evaluated for augmentor wing and externally blown flap STOL aircraft with the engines located both under and over the wings. Some supporting test data are presented. Optimum engines are selected based on achieving the performance, economic, acoustic, and pollution goals presently being considered for future STOL aircraft. The data and results presented were obtained from a number of contracted studies and some supporting NASA inhouse programs, most of which began in early 1972. The contracts include: (1) two aircraft and mission studies, (2) two propulsion system studies, (3) the experimental and analytic work on the augmentor wing, and (4) the experimental programs on Q-Fan. Engines are selected and discussed based on aircraft economics using the direct operating cost as the primary criterion. This cost includes the cost of the crew, fuel, aircraft, and engine maintenance and depreciation.

Traveling Magnetic Field Applications for Materials Processing in Space

NASA Technical Reports Server (NTRS)

Motakef, S.; Grugel, R. N.; Mazuruk, K.; Whitaker, Ann F. (Technical Monitor)

2001-01-01

Including the capability to induce a controlled fluid flow in the melt can significantly enrich research on solidification phenomena in a microgravity environment. The traveling magnetic field (TMF) is a promising technique to achieve this goal and is the aim of our ground-based project. In this presentation we will discuss new theoretical as well as experimental results recently obtained by our group. In particular, we experimentally demonstrated efficient mixing of metal alloys in long tubes subjected to TMF during processing. Application of this technique can be an elegant solution to ensure melt homogenization prior to solidification in a microgravity environment where natural convection is generally absent. Results of our theoretical work on TMF induced flows, such as convection control in Bridgman as well as in the Traveling Heater method, will be presented. Possible applications of TMF on board the ISS will also be discussed.

Use of an Expansion Tube to Examine Scramjet Combustion at Hypersonic Velocities

NASA Technical Reports Server (NTRS)

Rizkalla, Oussama; Bakos, Robert J.; Chinitz, Wallace; Pulsonetti, Maria V; Erdos, John I.

1989-01-01

Combustion testing at total enthalpy conditions corresponding to flight Math numbers in excess of 12 requires the use of impulse facilities. The expansion tube is the only operational facility of its size which can provide these conditions without excessive oxygen dissociation or driver gas contamination. Expansio tube operation is described herein and the operational parameters having the largest impact on its performance are determined. These are: driver-to-intermediate chamber pressure ratio, driver gas molecular weight and specific heat ratio, and driver gas temperature. Increases in the lase named parameter will markedly affect the test section static pressure. Preliminary calibration tests are discussed and test gas conditions which have been achieved are presented. Calculated and experimental test times are compared and the parameters affecting test time are discussed. The direction of future work using this important experimental tool is indicated.

Use of an expansion tube to examine scramjet combustion at hypersonic velocities

NASA Technical Reports Server (NTRS)

Rizkalla, O.; Bakos, R. J.; Pulsonetti, M.; Chinitz, Wallace; Erdos, John I.

1989-01-01

Combustion testing at total enthalpy conditions corresponding to flight Mach numbers in excess of 12 requires the use of impulse facilities. The expansion tube is the only operational facility of its size which can provide these conditions without excessive oxygen dissociation or driver gas contamination. Expansion tube operation is described herein and the operational parameters having the largest impact on its performance are determined. These are: driver-to-intermediate chamber pressure ratio, driver gas molecular weight and specific heat ratio, and driver gas temperature. Increases in the last-named parameter will markedly affect the test section static pressure. Preliminary calibration tests are discussed and test gas conditions which have been achieved are presented. Calculated and experimental test times are compared and the parameters affecting test time are discussed. The direction of future work using this important experimental tool is indicated.

Perspective on the prospects of a carrier multiplication nanocrystal solar cell.

PubMed

Nair, Gautham; Chang, Liang-Yi; Geyer, Scott M; Bawendi, Moungi G

2011-05-11

This article presents a perspective on the experimental and theoretical work to date on the efficiency of carrier multiplication (CM) in colloidal semiconductor nanocrystals (NCs). Early reports on CM in NCs suggested large CM efficiency enhancements. However, recent experiments have shown that CM in nanocrystalline samples is not significantly stronger, and often is weaker, than in the parent bulk when compared on an absolute photon energy basis. This finding is supported by theoretical consideration of the CM process and the competing intraband relaxation. We discuss the experimental artifacts that may have led to the apparently strong CM estimated in early reports. The finding of bulklike CM in NCs suggests that the main promise of quantum confinement is to boost the photovoltage at which carriers can be extracted. With this in mind, we discuss research directions that may result in effective use of CM in a solar cell.

Whole parasite blood stage malaria vaccines: a convergence of evidence.

PubMed

McCarthy, James S; Good, Michael F

2010-01-01

There is a growing realization of the limitations of recombinant protein-based malaria vaccines. This, coupled with a better understanding of the protective immunity to malaria, both in animal models and in naturally exposed human populations and experimentally infected volunteers, as well as the increased capacity to manipulate parasites provides new impetus to evaluate whole blood stage parasite approaches to malaria vaccine development. In this review previous studies in rodents and primates of whole killed and attenuated blood stage vaccines, and recent work on the effect of genetically attenuated parasites on immunity in rodent models of blood stage immunity are discussed. The relationship between these findings and what is now known about protective immunity in human populations, specifically against the blood stages of the parasite lifecycle is discussed and recent findings from human experimental infection are be reviewed. Finally, the prospect for and impediments to the development whole blood stage parasites are reviewed.

X-ray crystallography, an essential tool for the determination of thermodynamic relationships between crystalline polymorphs.

PubMed

Céolin, R; Rietveld, I-B

2016-01-01

After a short review of the controversies surrounding the discovery of crystalline polymorphism in relation to our present day understanding, the methods of how to solve the stability hierarchy of different polymorphs will be briefly discussed. They involve either theoretical calculations, or, more commonly, experimental methods based on classical thermodynamics. The experimental approach is mainly carried out using heat-exchange data associated to the transition of one form into another. It will be demonstrated that work-related data associated to the phase transition should be taken into account and the role of X-ray crystallography therein will be discussed. X-ray crystallography has become increasingly precise and can nowadays provide specific volumes and their differences as a function of temperature, and also as a function of pressure, humidity, and time. Copyright © 2015 Académie Nationale de Pharmacie. Published by Elsevier Masson SAS. All rights reserved.

Robust Online Hamiltonian Learning

NASA Astrophysics Data System (ADS)

Granade, Christopher; Ferrie, Christopher; Wiebe, Nathan; Cory, David

2013-05-01

In this talk, we introduce a machine-learning algorithm for the problem of inferring the dynamical parameters of a quantum system, and discuss this algorithm in the example of estimating the precession frequency of a single qubit in a static field. Our algorithm is designed with practicality in mind by including parameters that control trade-offs between the requirements on computational and experimental resources. The algorithm can be implemented online, during experimental data collection, or can be used as a tool for post-processing. Most importantly, our algorithm is capable of learning Hamiltonian parameters even when the parameters change from experiment-to-experiment, and also when additional noise processes are present and unknown. Finally, we discuss the performance of the our algorithm by appeal to the Cramer-Rao bound. This work was financially supported by the Canadian government through NSERC and CERC and by the United States government through DARPA. NW would like to acknowledge funding from USARO-DTO.

The effect of work-time influence on health and well-being: a quasi-experimental intervention study among eldercare workers.

PubMed

Nabe-Nielsen, Kirsten; Garde, Anne Helene; Diderichsen, Finn

2011-08-01

The aim of this study was to investigate the effect of work-time influence on stress and energy, work-family conflicts, lifestyle factors, and biomarkers of cardiovascular disease risk. The study was a quasi-experimental intervention study with a one-year follow-up among eldercare workers (baseline: n = 309; follow-up: n = 297). The nine work units in the intervention group designed their own intervention. We categorized these work units into three subgroups according to the interventions that they initiated: (A) self-scheduling via a computer program (n = 35), (B) setting up a task group that developed a questionnaire on work-time preference and participated in a one-day course on flexible working hours with the intention to increase employee influence on the fixed rota (n = 62), and (C) discussions of how employee work-time influence could be increased (n = 25). These subgroups were compared with a reference group consisting of ten work units (n = 187). Data consisted of questionnaires, blood samples, and measurements of waist and hip circumference. The employees in subgroup A became increasingly involved in the planning of their own work schedule. Nevertheless, we found no effect on health and well-being attributable to the intervention. The introduction of self-scheduling can successfully increase employee work-time influence. Yet, this study does not support the theory that increased work-time influence leads to better health and well-being.

Incubation and Intuition in Creative Problem Solving.

PubMed

Gilhooly, Kenneth J

2016-01-01

Creative problem solving, in which novel solutions are required, has often been seen as involving a special role for unconscious processes (Unconscious Work) which can lead to sudden intuitive solutions (insights) when a problem is set aside during incubation periods. This notion of Unconscious Work during incubation periods is supported by a review of experimental studies and particularly by studies using the Immediate Incubation paradigm. Other explanations for incubation effects, in terms of Intermittent Work or Beneficial Forgetting are considered. Some recent studies of divergent thinking, using the Alternative Uses task, carried out in my laboratory regarding Immediate vs. Delayed Incubation and the effects of resource competition from interpolated activities are discussed. These studies supported a role for Unconscious Work as against Intermittent Conscious work or Beneficial Forgetting in incubation.

Incubation and Intuition in Creative Problem Solving

PubMed Central

Gilhooly, Kenneth J.

2016-01-01

Creative problem solving, in which novel solutions are required, has often been seen as involving a special role for unconscious processes (Unconscious Work) which can lead to sudden intuitive solutions (insights) when a problem is set aside during incubation periods. This notion of Unconscious Work during incubation periods is supported by a review of experimental studies and particularly by studies using the Immediate Incubation paradigm. Other explanations for incubation effects, in terms of Intermittent Work or Beneficial Forgetting are considered. Some recent studies of divergent thinking, using the Alternative Uses task, carried out in my laboratory regarding Immediate vs. Delayed Incubation and the effects of resource competition from interpolated activities are discussed. These studies supported a role for Unconscious Work as against Intermittent Conscious work or Beneficial Forgetting in incubation. PMID:27499745

Group attributional training as an effective approach to human resource development under team work systems.

PubMed

Wang, Z M

1994-07-01

An experimental programme of group attributional training under team work system was conducted as part of human resource development in Chinese industrial enterprises. One hundred and ten shopfloor employees participated in the study. Among them, 58 employees took part in the factorial-designed experiment to find out the effects of attributions on performance, and 52 employees of ten work groups participated in the group attributional training programme twice a week for two months. The results showed that the group attributional training was effective in modifying employees' attributional patterns and enhancing group performance and satisfaction. On the basis of the results, an attributional model of work motivation is proposed, and its theoretical and practical implications for human resource management discussed.

Nuclear physics from Lattice QCD

NASA Astrophysics Data System (ADS)

Shanahan, Phiala

2017-09-01

I will discuss the current state and future scope of numerical Lattice Quantum Chromodynamics (LQCD) calculations of nuclear matrix elements. The goal of the program is to provide direct QCD calculations of nuclear observables relevant to experimental programs, including double-beta decay matrix elements, nuclear corrections to axial matrix elements relevant to long-baseline neutrino experiments and nuclear sigma terms needed for theory predictions of dark matter cross-sections at underground detectors. I will discuss the progress and challenges on these fronts, and also address recent work constraining a gluonic analogue of the EMC effect, which will be measurable at a future electron-ion collider.

Large-x connections of nuclear and high-energy physics

DOE PAGES

Accardi, Alberto

2013-11-20

I discuss how global QCD fits of parton distribution functions can make the somewhat separated fields of high-energy particle physics and lower energy hadronic and nuclear physics interact to the benefit of both. I review specific examples of this interplay from recent works of the CTEQ-Jefferson Lab collaboration, including hadron structure at large parton momentum and gauge boson production at colliders. Particular attention is devoted to quantifying theoretical uncertainties arising in the treatment of large partonic momentum contributions to deep inelastic scattering observables, and to discussing the experimental progress needed to reduce these.

Probing photocurrent generation mechanisms in hybrid IR-senstive quantum dot/conjugated polymer solar cells

NASA Astrophysics Data System (ADS)

Strein, Elisabeth

The work in this dissertation aims to improve the ability of hybrid polymer/quantum dot solar cells to harvest and utilize sunlight by contributing mechanistic insights into photocurrent generation. The mechanisms of charge transfer and energy transfer are explored spectroscopically in chapter three and both are found to contribute to photocurrent. Chapter four looks at excitation energy in excess of the bandgap and finds a rise in polaron yield which correlates with excess photon energy. Chapter two discusses details of the experimental techniques used to access the data discussed in the chapters that follow.

Mathematical outcomes and working memory in children with TBI and orthopedic injury.

PubMed

Raghubar, Kimberly P; Barnes, Marcia A; Prasad, Mary; Johnson, Chad P; Ewing-Cobbs, Linda

2013-03-01

This study compared mathematical outcomes in children with predominantly moderate to severe traumatic brain injury (TBI; n550) or orthopedic injury (OI; n547) at 2 and 24 months post-injury. Working memory and its contribution to math outcomes at 24 months post-injury was also examined. Participants were administered an experimental cognitive addition task and standardized measures of calculation, math fluency, and applied problems; as well as experimental measures of verbal and visual-spatial working memory. Although children with TBI did not have deficits in foundational math fact retrieval, they performed more poorly than OIs on standardized measures of math. In the TBI group, performance on standardized measures was predicted by age at injury, socioeconomic status, and the duration of impaired consciousness. Children with TBI showed impairments on verbal, but not visual working memory relative to children with OI. Verbal working memory mediated group differences on math calculations and applied problems at 24 months post-injury. Children with TBI have difficulties in mathematics, but do not have deficits in math fact retrieval, a signature deficit of math disabilities. Results are discussed with reference to models of mathematical cognition and disability and the role of working memory in math learning and performance for children with TBI.

Mathematical Outcomes and Working Memory in Children With TBI and Orthopedic Injury

PubMed Central

Raghubar, Kimberly P.; Barnes, Marcia A.; Prasad, Mary; Johnson, Chad P.; Ewing-Cobbs, Linda

2013-01-01

This study compared mathematical outcomes in children with predominantly moderate to severe traumatic brain injury (TBI; n =50) or orthopedic injury (OI; n=47) at 2 and 24 months post-injury. Working memory and its contribution to math outcomes at 24 months post-injury was also examined. Participants were administered an experimental cognitive addition task and standardized measures of calculation, math fluency, and applied problems; as well as experimental measures of verbal and visual-spatial working memory. Although children with TBI did not have deficits in foundational math fact retrieval, they performed more poorly than OIs on standardized measures of math. In the TBI group, performance on standardized measures was predicted by age at injury, socioeconomic status, and the duration of impaired consciousness. Children with TBI showed impairments on verbal, but not visual working memory relative to children with OI. Verbal working memory mediated group differences on math calculations and applied problems at 24 months post-injury. Children with TBI have difficulties in mathematics, but do not have deficits in math fact retrieval, a signature deficit of math disabilities. Results are discussed with reference to models of mathematical cognition and disability and the role of working memory in math learning and performance for children with TBI. PMID:23164058

Metacognitive and multimedia support of experiments in inquiry learning for science teacher preparation

NASA Astrophysics Data System (ADS)

Bruckermann, Till; Aschermann, Ellen; Bresges, André; Schlüter, Kirsten

2017-04-01

Promoting preservice science teachers' experimentation competency is required to provide a basis for meaningful learning through experiments in schools. However, preservice teachers show difficulties when experimenting. Previous research revealed that cognitive scaffolding promotes experimentation competency by structuring the learning process, while metacognitive and multimedia support enhance reflection. However, these support measures have not yet been tested in combination. Therefore, we decided to use cognitive scaffolding to support students' experimental achievements and supplement it by metacognitive and multimedia scaffolds in the experimental groups. Our research question is to what extent supplementing cognitive support by metacognitive and multimedia scaffolding further promotes experimentation competency. The intervention has been applied in a two-factorial design to a two-month experimental course for 63 biology teacher students in their first bachelor year. Pre-post-test measured experimentation competency in a performance assessment. Preservice teachers worked in groups of four. Therefore, measurement took place at group level (N = 16). Independent observers rated preservice teachers' group performance qualitatively on a theory-based system of categories. Afterwards, experimentation competency levels led to quantitative frequency analysis. The results reveal differing gains in experimentation competency but contrary to our hypotheses. Implications of combining scaffolding measures on promoting experimentation competency are discussed.

On the International Agency for Research on Cancer classification of glyphosate as a probable human carcinogen.

PubMed

Tarone, Robert E

2018-01-01

The recent classification by International Agency for Research on Cancer (IARC) of the herbicide glyphosate as a probable human carcinogen has generated considerable discussion. The classification is at variance with evaluations of the carcinogenic potential of glyphosate by several national and international regulatory bodies. The basis for the IARC classification is examined under the assumptions that the IARC criteria are reasonable and that the body of scientific studies determined by IARC staff to be relevant to the evaluation of glyphosate by the Monograph Working Group is sufficiently complete. It is shown that the classification of glyphosate as a probable human carcinogen was the result of a flawed and incomplete summary of the experimental evidence evaluated by the Working Group. Rational and effective cancer prevention activities depend on scientifically sound and unbiased assessments of the carcinogenic potential of suspected agents. Implications of the erroneous classification of glyphosate with respect to the IARC Monograph Working Group deliberative process are discussed.

An Investigation of the Effect of Surface Impurities on the Adsorption Kinetics of Hydrogen Chemisorbed onto Iron

NASA Technical Reports Server (NTRS)

Shanabarger, M. R.

1997-01-01

The original goal of this program was to investigate the effect surface impurities have on the heterogeneous kinetic processes of those molecular species which produce gaseous hydrogen degradation of the mechanical properties of metallic structural materials. However, shortly after the initiation of the original program, the program's NASA Technical Monitor, Dr. Howard Nelson, requested that the effort supported by this Co-operative Agreement be redirected to study more pressing materials issues associated to the development of the National Aero-Space Plane (NASP). The results of these efforts are outlined in this report. Detailed discussions of specific work, including experimental techniques and procedures, will be found in the publications listed with the subsection discussing that specific work as well and in Section 5. No inventions were generated or disclosed within this Agreement.

Discussion and theoretical summarization of the experimental data. [psychophysiology in human factors engineering

NASA Technical Reports Server (NTRS)

Mileryan, Y. A.

1975-01-01

A summary of research on psychological factors that cause substantial changes in the reliability indicators of an operators work is followed by a conclusion that strong moral-volitional qualities are the basic factors that make the human behavior under conditions of stress effective; emotional subcortical subdominants affect a person's conscious organization and self control in a man machine environment.

National Wind Tecnology Center Provides Dual Axis Resonant Blade Testing

ScienceCinema

Felker, Fort

2018-01-16

NREL's Structural Testing Laboratory at the National Wind Technology Center (NWTC) provides experimental laboratories, computer facilities for analytical work, space for assembling components and turbines for atmospheric testing as well as office space for industry researchers. Fort Felker, center director at the NWTC, discusses NREL's state-of-the-art structural testing capabilities and shows a flapwise and edgewise blade test in progress.

Core Ion Structures and Solvation Effects in Gas Phase [Sn(CO_{2})_{n}]^{-} Clusters

NASA Astrophysics Data System (ADS)

Thompson, Michael C.; Weber, J. Mathias

2017-06-01

We report infrared photodissociation spectra of [Sn(CO_{2})_{n}] (n=2-6) clusters. We explore core ion geometries through quantum chemical calculations and assign our experimental spectra through comparison with calculated vibrational frequencies. We discuss our results in the context of heterogeneous catalytic reduction of CO_{2}, and compare our results with previous work on other post-transition metal species.

Integrative Lifecourse and Genetic Analysis of Military Working Dogs

DTIC Science & Technology

2015-12-01

done as the samples are collected in order to avoid experimental variability and batch effects . Detailed description and discussion of this task...associated loss of power to detect all associations but those of large effect sizes) and latent variables (e.g., population structure – addressed in...processes associated with tissue development and maintenance are thus grouped with external environmental effects . This in turn suggests how those

Technology and equipment based on induction melters with ``cold'' crucible for reprocessing active metal waste

NASA Astrophysics Data System (ADS)

Pastushkov, V. G.; Molchanov, A. V.; Serebryakov, V. P.; Smelova, T. V.; Shestoperov, I. N.

2000-07-01

The paper discusses specific features of technology, equipment and control of a single stage RAMW decontamination and melting process in an induction furnace equipped with a "cold" crucible. The calculated and experimental data are given on melting high activity level stainless steel and Zr simulating high activity level metal waste. The work is under way in SSC RF VNIINM.

A Laser Based Fusion Test Facility

DTIC Science & Technology

2008-10-01

Nike laser have explored the intensities employed by these Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the...and best beam smoothing with KrF makes it the most resistant to such instability. As discussed above, recent experiments using the Nike facility...support this expectation. There is ongoing experimental and theoretical work on Nike , Omega, and eventually NIF to determine these intensity limits

Laboratory studies of the interaction of ions with condensed gases: Planetary applications

NASA Technical Reports Server (NTRS)

Boring, J. W.; Johnson, R. E.

1990-01-01

The work described is concerned with laboratory studies of the processes that produce the ejection of molecules from the surfaces of condensed gas solids, the change in the chemistry of the surface materials, and the relationship of these results to processes occurring in the solar system. Included is a discussion of the experimental techniques employed in making these laboratory measurements.

National Wind Tecnology Center Provides Dual Axis Resonant Blade Testing

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

Felker, Fort

2013-11-13

NREL's Structural Testing Laboratory at the National Wind Technology Center (NWTC) provides experimental laboratories, computer facilities for analytical work, space for assembling components and turbines for atmospheric testing as well as office space for industry researchers. Fort Felker, center director at the NWTC, discusses NREL's state-of-the-art structural testing capabilities and shows a flapwise and edgewise blade test in progress.

Enthalpy measurement of coal-derived liquids. Final report, April 1981-September 1983. [517 to 10342 kPa; 340 to 664 K

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

Kidnay, A.J.; Yesavage, V.F.

This report summarizes the results of experimental measurements of enthalpies for quinoline using a freon boil-off flow calorimeter, and an investigation of the applicability of cubic equations of state to correlating the enthalpy of coal-liquids. In Part A the compound quinoline is discussed. Process flow in the flow calorimeter, operational problems, and equipment modifications are described. Procedural modifications, including a new sample purification procedure, are described. Part B discusses the correlational effort. This includes a discussion of past correlational work and the difficulties associated with a general correlation for coal liquid enthalpy. In addition experimental data and computer generated predictionsmore » are presented. Three equations of state were used to predict vapor pressures and enthalpies for ten pure component systems previously studied in the lab. In general, the results were encouraging. All three equations were found to be effective in predicting both enthalpies and vapor pressures. In addition, the equations worked well when fit to mixture enthalpies. The Modified SRK equation was found to be superior to the other equations and modeled all properties for both associating and nonassociating systems well. The Modified SRK equation did have a drawback in that it was not readily generalized since it required two parameters which must be fit to data for best results. In sum, it was shown that a four parameter equation of state could be used successfully to correlate the enthalpy of coal-liquid model compounds.« less

Experimental instruction in photonics for high school students: approaches to managing problems faced

NASA Astrophysics Data System (ADS)

Choong, Zhengyang

2017-08-01

Student research projects are increasingly common at the K-12 level. However, students often face difficulties in the course of their school research projects such as setting realistic timelines and expectations, handling problems stemming from a lack of self-confidence, as well as being sufficiently disciplined for sustained communication and experimentation. In this work, we explore manifestations of these problems in the context of a photonics project, characterising the spectrum of the breakdown flash from Silicon Avalanche Photodiodes. We report on the process of planning and building the setup, data collection, analysis and troubleshooting, as well as the technical and human problems at each step. Approaches that were found to be helpful in managing the aforementioned problems are discussed, including an attention to detail during experimental work, as well as communicating in a forthcoming manner. Œe former allowed for clearer planning and the setting of quantifiable proximal goals; the latter helped in motivating discipline, and also helped in the understanding of research as an iterative learning process without a clear definition of success or failure.

Theoretical and experimental study of AC electrical conduction mechanism in the low temperature range of p-CuIn3Se5

NASA Astrophysics Data System (ADS)

Essaleh, L.; Amhil, S.; Wasim, S. M.; Marín, G.; Choukri, E.; Hajji, L.

2018-05-01

In the present work, an attempt has been made to study theoretically and experimentally the AC electrical conduction mechanism in disordered semiconducting materials. The key parameter considered in this analysis is the frequency exponent s(ω , T) =( ∂ln(σAC(ω , T))/∂ ln(ω)T , where σAC is the AC electrical conductivity that depends on angular frequency ω and temperature T. In the theoretical part of this work, the effect of the barrier hopping energy, the polaron radius and the characteristic relaxation time is considered. The theoretical models of Quantum Mechanical Tunneling (QMT), Non overlapping Small Polaron Tunneling (NSPT), Overlapping Large Polaron Tunneling (OLPT) and Correlated Barrier Hopping (CBH) are considered to fit experimental data of σAC in p-CuIn3Se5 (p-CIS135) in the low temperature range up to 96 K. Some important parameters, as the polaron radius, the localization length and the barrier hopping energies, are estimated and their temperature and frequency dependence discussed.

From Einstein-Podolsky-Rosen paradox to quantum nonlocality: experimental investigation of quantum correlations

NASA Astrophysics Data System (ADS)

Xu, Jin-Shi; Li, Chuan-Feng; Guo, Guang-Can

2016-11-01

In 1935, Einstein, Podolsky and Rosen published their influential paper proposing a now famous paradox (the EPR paradox) that threw doubt on the completeness of quantum mechanics. Two fundamental concepts: entanglement and steering, were given in the response to the EPR paper by Schrodinger, which both reflect the nonlocal nature of quantum mechanics. In 1964, John Bell obtained an experimentally testable inequality, in which its violation contradicts the prediction of local hidden variable models and agrees with that of quantum mechanics. Since then, great efforts have been made to experimentally investigate the nonlocal feature of quantum mechanics and many distinguished quantum properties were observed. In this work, along with the discussion of the development of quantum nonlocality, we would focus on our recent experimental efforts in investigating quantum correlations and their applications with optical systems, including the study of entanglement-assisted entropic uncertainty principle, Einstein-Podolsky-Rosen steering and the dynamics of quantum correlations.

Experimental study on flow boiling heat transfer of LNG in a vertical smooth tube

NASA Astrophysics Data System (ADS)

Chen, Dongsheng; Shi, Yumei

2013-10-01

An experimental apparatus is set up in this work to study the upward flow boiling heat transfer characteristics of LNG (liquefied natural gas) in vertical smooth tubes with inner diameters of 8 mm and 14 mm. The experiments were performed at various inlet pressures from 0.3 to 0.7 MPa. The results were obtained over the mass flux range from 16 to 200 kg m-2 s-1 and heat fluxes ranging from 8.0 to 32 kW m-2. The influences of quality, heat flux and mass flux, tube diameter on the heat transfer characteristic are examined and discussed. The comparisons of the experimental heat transfer coefficients with the predicted values from the existing correlations are analyzed. The correlation by Zou et al. [16] shows the best accuracy with the RMS deviation of 31.7% in comparison with the experimental data.

Vapor Phase Catalytic Ammonia Reduction

NASA Technical Reports Server (NTRS)

Flynn, Michael T.; Harper, Lynn D. (Technical Monitor)

1994-01-01

This paper discusses the development of a Vapor Phase Catalytic Ammonia Reduction (VPCAR) teststand and the results of an experimental program designed to evaluate the potential of the technology as a water purification process. In the experimental program the technology is evaluated based upon product water purity, water recovery rate, and power consumption. The experimental work demonstrates that the technology produces high purity product water and attains high water recovery rates at a relatively high specific power consumption. The experimental program was conducted in 3 phases. In phase I an Igepon(TM) soap and water mixture was used to evaluate the performance of an innovative Wiped-Film Rotating-Disk evaporator and associated demister. In phase II a phenol-water solution was used to evaluate the performance of the high temperature catalytic oxidation reactor. In phase III a urine analog was used to evaluate the performance of the combined distillation/oxidation functions of the processor.

Maternal employment and the health of low-income young children.

PubMed

Gennetian, Lisa A; Hill, Heather D; London, Andrew S; Lopoo, Leonard M

2010-05-01

This study examines whether maternal employment affects the health status of low-income, elementary-school-aged children using instrumental variables estimation and experimental data from a welfare-to-work program implemented in the early 1990s. Maternal report of child health status is predicted as a function of exogenous variation in maternal employment associated with random assignment to the experimental group. IV estimates show a modest adverse effect of maternal employment on children's health. Making use of data from another welfare-to-work program we propose that any adverse effect on child health may be tempered by increased family income and access to public health insurance coverage, findings with direct relevance to a number of current policy discussions. In a secondary analysis using fixed effects techniques on longitudinal survey data collected in 1998 and 2001, we find a comparable adverse effect of maternal employment on child health that supports the external validity of our primary result.

An investigation into electromagnetic force models: differences in global and local effects demonstrated by selected problems

NASA Astrophysics Data System (ADS)

Reich, Felix A.; Rickert, Wilhelm; Müller, Wolfgang H.

2018-03-01

This study investigates the implications of various electromagnetic force models in macroscopic situations. There is an ongoing academic discussion which model is "correct," i.e., generally applicable. Often, gedankenexperiments with light waves or photons are used in order to motivate certain models. In this work, three problems with bodies at the macroscopic scale are used for computing theoretical model-dependent predictions. Two aspects are considered, total forces between bodies and local deformations. By comparing with experimental data, insight is gained regarding the applicability of the models. First, the total force between two cylindrical magnets is computed. Then a spherical magnetostriction problem is considered to show different deformation predictions. As a third example focusing on local deformations, a droplet of silicone oil in castor oil is considered, placed in a homogeneous electric field. By using experimental data, some conclusions are drawn and further work is motivated.

Multi-scale mechanics of granular solids from grain-resolved X-ray measurements

NASA Astrophysics Data System (ADS)

Hurley, R. C.; Hall, S. A.; Wright, J. P.

2017-11-01

This work discusses an experimental technique for studying the mechanics of three-dimensional (3D) granular solids. The approach combines 3D X-ray diffraction and X-ray computed tomography to measure grain-resolved strains, kinematics and contact fabric in the bulk of a granular solid, from which continuum strains, grain stresses, interparticle forces and coarse-grained elasto-plastic moduli can be determined. We demonstrate the experimental approach and analysis of selected results on a sample of 1099 stiff, frictional grains undergoing multiple uniaxial compression cycles. We investigate the inter-particle force network, elasto-plastic moduli and associated length scales, reversibility of mechanical responses during cyclic loading, the statistics of microscopic responses and microstructure-property relationships. This work serves to highlight both the fundamental insight into granular mechanics that is furnished by combined X-ray measurements and describes future directions in the field of granular materials that can be pursued with such approaches.

A lateral dynamics of a wheelchair: identification and analysis of tire parameters.

PubMed

Silva, L C A; Corrêa, F C; Eckert, J J; Santiciolli, F M; Dedini, F G

2017-02-01

In vehicle dynamics studies, the tire behaviour plays an important role in planar motion of the vehicle. Therefore, a correct representation of tire is a necessity. This paper describes a mathematical model for wheelchair tire based on the Magic Formula model. This model is widely used to represent forces and moments between the tire and the ground; however some experimental parameters must be determined. The purpose of this work is to identify the tire parameters for the wheelchair tire model, implementing them in a dynamic model of the wheelchair. For this, we developed an experimental test rig to measure the tires parameters for the lateral dynamics of a wheelchair. This dynamic model was made using a multi-body software and the wheelchair behaviour was analysed and discussed according to the tire parameters. The result of this work is one step further towards the understanding of wheelchair dynamics.

The Sexual Offences (NI) Order 2008: implications for nurses.

PubMed

Daniels, Pauline; McAlinden, Orla

This article outlines the changes to the definition of sexual offences in Northern Ireland following the implementation of the Sexual Offences Northern Ireland Order 2008 in 2009, and its implications for nurses working with sexually active children in a range of clinical settings. The paper outlines the key changes for practice and addresses the needs of children in three different age groups with emphasis on children aged 13-15 years, and reviews mandatory reporting, the difference between the rights of children to consent and confidentiality, developmental sexual experimentation and sexual health protection. It reviews related policy and guidance and makes clear the differences between sexual abuse and exploitation, and experimentation. It seeks to advise the Safeguarding Committee of the Department of Health Northern Ireland on how best to support nurses working with sexually active children and when this activity should be discussed with line managers and safeguarding specialists or referred to the safeguarding authorities.

Review of the synergies between computational modeling and experimental characterization of materials across length scales

DOE PAGES

Dingreville, Rémi; Karnesky, Richard A.; Puel, Guillaume; ...

2015-11-16

With the increasing interplay between experimental and computational approaches at multiple length scales, new research directions are emerging in materials science and computational mechanics. Such cooperative interactions find many applications in the development, characterization and design of complex material systems. This manuscript provides a broad and comprehensive overview of recent trends in which predictive modeling capabilities are developed in conjunction with experiments and advanced characterization to gain a greater insight into structure–property relationships and study various physical phenomena and mechanisms. The focus of this review is on the intersections of multiscale materials experiments and modeling relevant to the materials mechanicsmore » community. After a general discussion on the perspective from various communities, the article focuses on the latest experimental and theoretical opportunities. Emphasis is given to the role of experiments in multiscale models, including insights into how computations can be used as discovery tools for materials engineering, rather than to “simply” support experimental work. This is illustrated by examples from several application areas on structural materials. In conclusion this manuscript ends with a discussion on some problems and open scientific questions that are being explored in order to advance this relatively new field of research.« less

A technique for plasma velocity-space cross-correlation

NASA Astrophysics Data System (ADS)

Mattingly, Sean; Skiff, Fred

2018-05-01

An advance in experimental plasma diagnostics is presented and used to make the first measurement of a plasma velocity-space cross-correlation matrix. The velocity space correlation function can detect collective fluctuations of plasmas through a localized measurement. An empirical decomposition, singular value decomposition, is applied to this Hermitian matrix in order to obtain the plasma fluctuation eigenmode structure on the ion distribution function. A basic theory is introduced and compared to the modes obtained by the experiment. A full characterization of these modes is left for future work, but an outline of this endeavor is provided. Finally, the requirements for this experimental technique in other plasma regimes are discussed.

Single wheel hub motor failures and their impact on vehicle and driver behaviour

NASA Astrophysics Data System (ADS)

Wanner, Daniel; Kreußlein, Maria; Augusto, Bruno; Drugge, Lars; Stensson Trigell, Annika

2016-10-01

This research work studies the impact of single wheel hub motor failures on the dynamic behaviour of electric vehicles and the corresponding driver reactions. An experimental study in a moving-base driving simulator is conducted to analyse the influence of single wheel hub motor failures for motorway speeds. Driver reaction times are derived from the measured data and discussed in their experimental context. The failure is rated objectively on the dynamic behaviour of the vehicle and compared to the subjective evaluation. Findings indicate that critical traffic situations impairing traffic safety can occur for motorway speeds. Clear counteractions by the drivers had to be taken.

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.

Combustion of LOX with H2(sub g) under subcritical, critical, and supercritical conditions (Task 1) and experimental observation of dense spray and mixing of impinging jets (Task 2)

NASA Technical Reports Server (NTRS)

Kuo, K. K.; Hsieh, W. H.; Cheung, F. B.; Yang, A. S.; Brown, J. J.; Woodward, R. D.; Kline, M. C.; Burch, R. L.

1992-01-01

The objective was to achieve a better understanding of the combustion processes of liquid oxygen and gaseous hydrogen under broad range of pressure covering subcritical, critical, and supercritical conditions. The scope of the experimental work falls into the following areas: (1) design of the overall experimental setup; (2) modification of an existing windowed high pressure chamber; (3) design of the LOX feeding system; (4) provision of the safety features in the test rig design; (5) LOX cleanliness requirements; (6) cold shock testing; (7) implementation of data acquisition systems; (8) preliminary tests for system checkout; (9) modification of LOX feeding system; and (10) evaporation tests. Progress in each area is discussed.

Benchmark of FDNS CFD Code For Direct Connect RBCC Test Data

NASA Technical Reports Server (NTRS)

Ruf, J. H.

2000-01-01

Computational Fluid Dynamics (CFD) analysis results are compared with experimental data from the Pennsylvania State University's (PSU) Propulsion Engineering Research Center (PERC) rocket based combined cycle (RBCC) rocket-ejector experiments. The PERC RBCC experimental hardware was in a direct-connect configuration in diffusion and afterburning (DAB) operation. The objective of the present work was to validate the Finite Difference Navier Stokes (FDNS) CFD code for the rocket-ejector mode internal fluid mechanics and combustion phenomena. A second objective was determine the best application procedures to use FDNS as a predictive/engineering tool. Three-dimensional CFD analysis was performed. Solution methodology and grid requirements are discussed. CFD results are compared to experimental data for static pressure, Raman Spectroscopy species distribution data and RBCC net thrust and specified impulse.

Near-Threshold Ionization of Argon by Positron Impact

NASA Astrophysics Data System (ADS)

Babij, T. J.; Machacek, J. R.; Murtagh, D. J.; Buckman, S. J.; Sullivan, J. P.

2018-03-01

The direct single-ionization cross section for Ar by positron impact has been measured in the region above the first ionization threshold. These measurements are compared to semiclassical calculations which give rise to a power law variation of the cross section in the threshold region. The experimental results appear to be in disagreement with extensions to the Wannier theory applied to positron impact ionization, with a smaller exponent than that calculated by most previous works. In fact, in this work, we see no difference in threshold behavior between the positron and electron cases. Possible reasons for this discrepancy are discussed.

Solid-state lasers for coherent communication and remote sensing

NASA Technical Reports Server (NTRS)

Byer, Robert L.

1991-01-01

Work in the stabilization of monolithic Nd:YAG lasers and the application of these lasers to nonlinear optical frequency conversion is discussed. The intrinsic stability of semiconductor diode laser pumped solid state lasers has facilitated a number of demonstration in external resonant cavity harmonic generation and stable optical parametric oscillation. Relative laser frequency stabilization of 0.3 Hz was achieved, and absolute stability of a few hundred hertz is anticipated. The challenge is now to reproduce this frequency stability in the output of tunable nonlinear optical devices. Theoretical and experimental work toward this goal are continuing.

The Intersection of Theory and Application in Elucidating Pattern Formation in Developmental Biology

PubMed Central

Othmer, Hans G.; Painter, Kevin; Umulis, David; Xue, Chuan

2009-01-01

We discuss theoretical and experimental approaches to three distinct developmental systems that illustrate how theory can influence experimental work and vice-versa. The chosen systems – Drosophila melanogaster, bacterial pattern formation, and pigmentation patterns – illustrate the fundamental physical processes of signaling, growth and cell division, and cell movement involved in pattern formation and development. These systems exemplify the current state of theoretical and experimental understanding of how these processes produce the observed patterns, and illustrate how theoretical and experimental approaches can interact to lead to a better understanding of development. As John Bonner said long ago ‘We have arrived at the stage where models are useful to suggest experiments, and the facts of the experiments in turn lead to new and improved models that suggest new experiments. By this rocking back and forth between the reality of experimental facts and the dream world of hypotheses, we can move slowly toward a satisfactory solution of the major problems of developmental biology.’ PMID:19844610

IYPT problems teach high school students about teamwork and the scientific method

NASA Astrophysics Data System (ADS)

Kochanski, K.; Klishin, A.

2015-12-01

Laboratory work is often STEM students' primary exposure to key creative and communicative skills in the sciences, including experimental design, trouble shooting, team work, and oral presentations. The International Young Physicists' Tournament (IYPT) teaches these skills by inviting high school students to investigate simple unsolved systems instead of reproducing familiar results. Students work in teams to form hypotheses, gather data, and present their results orally in a tournament format. The IYPT has published 17 questions yearly since 1988, and its archives are an efficient source of experimental problems for outreach programs and have also been used for first-year undergraduate project classes (Planisic, 2009). We present insights and outcomes from two schools in which we introduced a new extracurricular program based on the IYPT model. Twenty-four students worked in small teams for three hours per day for six weeks. Surprisingly, most teams chose problems in unfamiliar subject areas such as fluid dynamics, and tailored their approaches to take advantage of individual skills including soldering, photography, and theoretical analysis. As the program progressed, students developed an increasingly intuitive understanding of the scientific method. They began to discuss the repeatability of their experiments without prompting, and were increasingly willing to describe alternative hypotheses.

An Evaluation of Aviation Maintenance Fatigue Countermeasures Training

DTIC Science & Technology

2013-05-01

home and work), and reaction to the training experience . METHOD A quasi-experimental5 one - group pretest - posttest design with a follow-up assessment...the instructor led a group discussion and then reviewed the content with the class before conducting a check on understanding and knowledge with...Questionnaires were administered up to one week before training, at the end of training, and six weeks following training. The training was effective in

SEGR in SiO$${}_2$$ –Si$$_3$$ N$$_4$$ Stacks

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

Javanainen, Arto; Ferlet-Cavrois, Veronique; Bosser, Alexandre

2014-04-17

This work presents experimental SEGR data for MOS-devices, where the gate dielectrics are are made of stacked SiO 2–Si 3N 4 structures. Also a semi-empirical model for predicting the critical gate voltage in these structures under heavy-ion exposure is proposed. Then statistical interrelationship between SEGR cross-section data and simulated energy deposition probabilities in thin dielectric layers is discussed.

Structural response synthesis

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

Ozisik, H.; Keltie, R.F.

The open loop control technique of predicting a conditioned input signal based on a specified output response for a second order system has been analyzed both analytically and numerically to gain a firm understanding of the method. Differences between this method of control and digital closed loop control using pole cancellation were investigated as a follow up to previous experimental work. Application of the technique to diamond turning using a fast tool is also discussed.

Electroencephalographic studies of sleep

NASA Technical Reports Server (NTRS)

Webb, W. B.; Agnew, H. W., Jr.

1975-01-01

Various experimental studies on sleep are described. The following areas are discussed: (1) effect of altered day length on sleep, (2) effect of a partial loss of sleep on subsequent nocturnal sleep; (3) effect of rigid control over sleep-wake-up times; (4) sleep and wakefulness in a time-free environment; (5) distribution of spindles during a full night of sleep; and (6) effect on sleep and performance of swiftly changing shifts of work.

LOGIC NETS, THEIR CHARACTERIZATION, RELIABILITY, AND EFFICIENT SYNTHESIS.

DTIC Science & Technology

The report consists of two parts. The first discusses a problem in the dual-support approach to network synthesis using threshold gates, gives new...asymptotic results on the number of threshold gates and the size of threshold gate networks, and summarizes the work in threshold logic supported by...this contract, including programs to facilitate experimentation in the design of networks of threshold gates. The second summarizes CDL1 - Computer

Long term radiocesium contamination of fruit trees following the Chernobyl accident.

PubMed

Antonopoulos-Domis, M; Clouvas, A; Gagianas, A

1996-12-01

Radiocesium contamination from the Chernobyl accident of fruits and leaves from various fruit trees was systematically studied from 1990 to 1995 on two agricultural experimentation farms in Northern Greece. The results are discussed in the framework of a previously published model describing the long-term radiocesium contamination mechanism of deciduous fruit trees after a nuclear accident. The results of the present work qualitatively verify the model predictions.

Study of lnter-Molecular Dynamics within Alkylsiloxane Self-Assembled Monolayer and Elastomer Systems

NASA Astrophysics Data System (ADS)

Roman, Michael

In this work, molecular motion, and in particular, glassy relaxations are studied in two novel experimental systems. Both experimental systems offer a significant degree of control over molecule-molecule, or group-group (where group refers to a portion of a molecule), interactions by controlling density and the type of inter-molecular interaction. Both systems have rigid elements that decrease the tendency of bulk materials to spontaneously change their density with temperature. Thus, density can be maintained and controlled and the effect of density and temperature can be (at least in part) de-convolved. The goal of this work is to experimentally observe the transition from simple, local relaxations to glassy dynamics as density is increased and to understand how this transition differs as the inter-molecular interactions are altered. In both approaches, the system is fabricated from individual parts where the nature, spacing, and particular arrangement of the parts can be controlled and the resultant changes in molecular motion can be observed. Building up a custom system from parts enables fundamental investigation into the glass transition (as discussed above) and also makes possible the development of materials that have engineered responses as a function of temperature. As a short-hand, we refer to the two systems as the monolayer or SAM (short for Self-Assembled Monolayer) and elastomer approaches. In Chapters 4-7 we discuss results from the monolayer approach. Chapter 8 summarizes results from the elastomer approach. In particular, Chapter 4 introduces you to dielectric spectroscopy and briefly summarizes the previous work by former students in the Clarke group which identified the local and glass relaxations in silane monolayers of substituted alkyl chains as analogous to the local and glassy relaxations in polymeric systems containing phase segregated alkyl chains, and similar to the local and glass modes in poly(ethylene). The remainder of Chapter 4 summarizes my own work to clearly delineate the transition from non-interacting behavior at low density (a partially-filled monolayer) to glassy behavior (with or without the presence of a local mode) as density is increased. In Chapter 5, I determined that this transition is highly robust to sample preparation technique. In Chapter 6, the effect of different inter-molecular interactions (dipole strength) on this transition and the resultant glassy state is discussed. Chapter 7 discusses changes in the local modes and the distribution of local and glass modes in the system as a function of terminal dipole strength. In chapter 8, elastomers are studied and the effect of backbone composition and distance between crosslinks is shown. This elastomer system can serve as a new substrate on which similar experiments as conducted with mono layers can be undertaken.

Backward Dependencies and in-Situ wh-Questions as Test Cases on How to Approach Experimental Linguistics Research That Pursues Theoretical Linguistics Questions

PubMed Central

Pablos, Leticia; Doetjes, Jenny; Cheng, Lisa L.-S.

2018-01-01

The empirical study of language is a young field in contemporary linguistics. This being the case, and following a natural development process, the field is currently at a stage where different research methods and experimental approaches are being put into question in terms of their validity. Without pretending to provide an answer with respect to the best way to conduct linguistics related experimental research, in this article we aim at examining the process that researchers follow in the design and implementation of experimental linguistics research with a goal to validate specific theoretical linguistic analyses. First, we discuss the general challenges that experimental work faces in finding a compromise between addressing theoretically relevant questions and being able to implement these questions in a specific controlled experimental paradigm. We discuss the Granularity Mismatch Problem (Poeppel and Embick, 2005) which addresses the challenges that research that is trying to bridge the representations and computations of language and their psycholinguistic/neurolinguistic evidence faces, and the basic assumptions that interdisciplinary research needs to consider due to the different conceptual granularity of the objects under study. To illustrate the practical implications of the points addressed, we compare two approaches to perform linguistic experimental research by reviewing a number of our own studies strongly grounded on theoretically informed questions. First, we show how linguistic phenomena similar at a conceptual level can be tested within the same language using measurement of event-related potentials (ERP) by discussing results from two ERP experiments on the processing of long-distance backward dependencies that involve coreference and negative polarity items respectively in Dutch. Second, we examine how the same linguistic phenomenon can be tested in different languages using reading time measures by discussing the outcome of four self-paced reading experiments on the processing of in-situ wh-questions in Mandarin Chinese and French. Finally, we review the implications that our findings have for the specific theoretical linguistics questions that we originally aimed to address. We conclude with an overview of the general insights that can be gained from the role of structural hierarchy and grammatical constraints in processing and the existing limitations on the generalization of results. PMID:29375417

Backward Dependencies and in-Situ wh-Questions as Test Cases on How to Approach Experimental Linguistics Research That Pursues Theoretical Linguistics Questions.

PubMed

Pablos, Leticia; Doetjes, Jenny; Cheng, Lisa L-S

2017-01-01

The empirical study of language is a young field in contemporary linguistics. This being the case, and following a natural development process, the field is currently at a stage where different research methods and experimental approaches are being put into question in terms of their validity. Without pretending to provide an answer with respect to the best way to conduct linguistics related experimental research, in this article we aim at examining the process that researchers follow in the design and implementation of experimental linguistics research with a goal to validate specific theoretical linguistic analyses. First, we discuss the general challenges that experimental work faces in finding a compromise between addressing theoretically relevant questions and being able to implement these questions in a specific controlled experimental paradigm. We discuss the Granularity Mismatch Problem (Poeppel and Embick, 2005) which addresses the challenges that research that is trying to bridge the representations and computations of language and their psycholinguistic/neurolinguistic evidence faces, and the basic assumptions that interdisciplinary research needs to consider due to the different conceptual granularity of the objects under study. To illustrate the practical implications of the points addressed, we compare two approaches to perform linguistic experimental research by reviewing a number of our own studies strongly grounded on theoretically informed questions. First, we show how linguistic phenomena similar at a conceptual level can be tested within the same language using measurement of event-related potentials (ERP) by discussing results from two ERP experiments on the processing of long-distance backward dependencies that involve coreference and negative polarity items respectively in Dutch. Second, we examine how the same linguistic phenomenon can be tested in different languages using reading time measures by discussing the outcome of four self-paced reading experiments on the processing of in-situ wh -questions in Mandarin Chinese and French. Finally, we review the implications that our findings have for the specific theoretical linguistics questions that we originally aimed to address. We conclude with an overview of the general insights that can be gained from the role of structural hierarchy and grammatical constraints in processing and the existing limitations on the generalization of results.

AORTIC COARCTATION: RECENT DEVELOPMENTS IN EXPERIMENTAL AND COMPUTATIONAL METHODS TO ASSESS TREATMENTS FOR THIS SIMPLE CONDITION

PubMed Central

LaDisa, John F.; Taylor, Charles A.; Feinstein, Jeffrey A.

2010-01-01

Coarctation of the aorta (CoA) is often considered a relatively simple disease, but long-term outcomes suggest otherwise as life expectancies are decades less than in the average population and substantial morbidity often exists. What follows is an expanded version of collective work conducted by the authors’ and numerous collaborators that was presented at the 1st International Conference on Computational Simulation in Congenital Heart Disease pertaining to recent advances for CoA. The work begins by focusing on what is known about blood flow, pressure and indices of wall shear stress (WSS) in patients with normal vascular anatomy from both clinical imaging and the use of computational fluid dynamics (CFD) techniques. Hemodynamic alterations observed in CFD studies from untreated CoA patients and those undergoing surgical or interventional treatment are subsequently discussed. The impact of surgical approach, stent design and valve morphology are also presented for these patient populations. Finally, recent work from a representative experimental animal model of CoA that may offer insight into proposed mechanisms of long-term morbidity in CoA is presented. PMID:21152106

Experimental test of a hot water storage system including a macro-encapsulated phase change material (PCM)

NASA Astrophysics Data System (ADS)

Mongibello, L.; Atrigna, M.; Bianco, N.; Di Somma, M.; Graditi, G.; Risi, N.

2017-01-01

Thermal energy storage systems (TESs) are of fundamental importance for many energetic systems, essentially because they permit a certain degree of decoupling between the heat or cold production and the use of the heat or cold produced. In the last years, many works have analysed the addition of a PCM inside a hot water storage tank, as it can allow a reduction of the size of the storage tank due to the possibility of storing thermal energy as latent heat, and as a consequence its cost and encumbrance. The present work focuses on experimental tests realized by means of an indoor facility in order to analyse the dynamic behaviour of a hot water storage tank including PCM modules during a charging phase. A commercial bio-based PCM has been used for the purpose, with a melting temperature of 58°C. The experimental results relative to the hot water tank including the PCM modules are presented in terms of temporal evolution of the axial temperature profile, heat transfer and stored energy, and are compared with the ones obtained by using only water as energy storage material. Interesting insights, relative to the estimation of the percentage of melted PCM at the end of the experimental test, are presented and discussed.

Working Together: Contributions of Corpus Analyses and Experimental Psycholinguistics to Understanding Conversation.

PubMed

Meyer, Antje S; Alday, Phillip M; Decuyper, Caitlin; Knudsen, Birgit

2018-01-01

As conversation is the most important way of using language, linguists and psychologists should combine forces to investigate how interlocutors deal with the cognitive demands arising during conversation. Linguistic analyses of corpora of conversation are needed to understand the structure of conversations, and experimental work is indispensable for understanding the underlying cognitive processes. We argue that joint consideration of corpus and experimental data is most informative when the utterances elicited in a lab experiment match those extracted from a corpus in relevant ways. This requirement to compare like with like seems obvious but is not trivial to achieve. To illustrate this approach, we report two experiments where responses to polar (yes/no) questions were elicited in the lab and the response latencies were compared to gaps between polar questions and answers in a corpus of conversational speech. We found, as expected, that responses were given faster when they were easy to plan and planning could be initiated earlier than when they were harder to plan and planning was initiated later. Overall, in all but one condition, the latencies were longer than one would expect based on the analyses of corpus data. We discuss the implication of this partial match between the data sets and more generally how corpus and experimental data can best be combined in studies of conversation.

Flat plate solar collector for water pre-heating using concentrated solar power (CSP)

NASA Astrophysics Data System (ADS)

Peris, Leonard Sunny; Shekh, Md. Al Amin; Sarker, Imran

2017-12-01

Numerous attempt and experimental conduction on different methods to harness energy from renewable sources are being conducted. This study is a contribution to the purpose of harnessing solar energy as a renewable source by using flat plate solar collector medium to preheat water. Basic theory of solar radiation and heat convection in water (working fluid) has been combined with heat conduction process by using copper tubes and aluminum absorber plate in a closed conduit, covered with a glazed through glass medium. By this experimental conduction, a temperature elevation of 35°C in 10 minutes duration which is of 61.58% efficiency range (maximum) has been achieved. The obtained data and experimental findings are validated with the theoretical formulation and an experimental demonstration model. A cost effective and simple form of heat energy extraction method for space heating/power generation has been thoroughly discussed with possible industrial implementation possibilities. Under-developed and developing countries can take this work as an illustration for renewable energy utilization for sustainable energy prospect. Also a full structure based data to derive concentrated solar energy in any geographical location of Bangladesh has been outlined in this study. These research findings can contribute to a large extent for setting up any solar based power plant in Bangladesh irrespective of its installation type.

Trace elemental analysis of human breast cancerous blood by advanced PC-WDXRF technique

NASA Astrophysics Data System (ADS)

Singh, Ranjit; Kainth, Harpreet Singh; Prasher, Puneet; Singh, Tejbir

2018-03-01

The objective of this work is to quantify the trace elements of healthy and non-healthy blood samples by using advanced polychromatic source based wavelength dispersive X-ray fluorescence (PC-WDXRF) technique. The imbalances in trace elements present in the human blood directly or indirectly lead to the carcinogenic process. The trace elements 11Na, 12Mg, 15P, 16S, 17Cl, 19K, 20Ca, 26Fe, 29Cu and 30Zn are identified and their concentrations are estimated. The experimental results clearly discuss the variation and role of various trace elements present in the non-healthy blood samples relative to the healthy blood samples. These results establish future guidelines to probe the possible roles of essential trace elements in the breast carcinogenic processes. The instrumental sensitivity and detection limits for measuring the elements in the atomic range 11 ≤ Z ≤ 30 have also been discussed in the present work.

Extreme events in optics: Challenges of the MANUREVA project

NASA Astrophysics Data System (ADS)

Dudley, J. M.; Finot, C.; Millot, G.; Garnier, J.; Genty, G.; Agafontsev, D.; Dias, F.

2010-07-01

In this contribution we describe and discuss a series of challenges and questions relating to understanding extreme wave phenomena in optics. Many aspects of these questions are being studied in the framework of the MANUREVA project: a multidisciplinary consortium aiming to carry out mathematical, numerical and experimental studies in this field. The central motivation of this work is the 2007 results from optical physics [D. Solli et al., Nature 450, 1054 (2007)] that showed how a fibre-optical system can generate large amplitude extreme wave events with similar statistical properties to the infamous hydrodynamic rogue waves on the surface of the ocean. We review our recent work in this area, and discuss how this observation may open the possibility for an optical system to be used to directly study both the dynamics and statistics of extreme-value processes, a potential advance comparable to the introduction of optical systems to study chaos in the 1970s.

The use of instruments for gravity related research

NASA Astrophysics Data System (ADS)

van Loon, J. J. W.

The first experiments using machines and instruments to manipulate gravity and thus learn about the impact of gravity onto living systems were performed by T A Knight in 1806 exactly 2 centuries ago What have we learned from these experiments and in particular what have we leaned about the use of instruments to reveal the impact of gravity and rotation onto plants and other living systems In this overview paper I will introduce the use of various instruments for gravity related research From water wheel to Random Positioning Machine RPM from clinostat to Free Fall Machine FFM and Rotating Wall Vessel RWV the usefulness and working principles of these microgravity simulators will be discussed We will discuss the question whether the RPM is a useful microgravity simulator and how to interpret experimental results This work is supported by NWO-ALW-SRON grant MG-057

Demonstration Tokamak Hybrid Reactor (DTHR) blanket design study, December 1978

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

Not Available

1978-01-01

This work represents only the second iteration of the conceptual design of a DTHR blanket; consequently, a number of issues important to a detailed blanket design have not yet been evaluated. The most critical issues identified are those of two-phase flow maldistribution, flow instabilities, flow stratification for horizontal radial inflow of boiling water, fuel rod vibrations, corrosion of clad and structural materials by high quality steam, fretting and cyclic loads. Approaches to minimizing these problems are discussed and experimental testing with flow mock-ups is recommended. These implications on a commercial blanket design are discussed and critical data needs are identified.

The development of kilohertz planar laser diagnostics for applications in high power turbulent flames

NASA Astrophysics Data System (ADS)

Slabaugh, Carson Daniel

In modern gas-turbine combustors, flame stabilization is achieved by inducing exhaust gas circulation within the flame zone through swirl-induced vortex breakdown. Swirling flows exhibit strong shear regions resulting in high turbulence and effective mixing. In combustion, these flows are characterized by complex unsteady interactions between turbulent flow structures and chemical reactions. Developments in high-resolution, quantitative, experimental measurement techniques must continue to improve fundamental understanding and support modeling efforts. This work describes the development of a gas turbine combustion experiment to support the application of advanced optical measurement techniques in flames operating at realistic engine conditions. Facility requirements are addressed, including instrumentation and control needs for remote operation when working with high energy flows. The methodology employed in the design of the optically-accessible combustion chamber is elucidated, including window considerations and thermal management of the experimental hardware under extremely high heat loads. Experimental uncertainties are also quantified. The stable operation of the experiment is validated using multiple techniques and the boundary conditions are verified. The successful prediction of operating conditions by the design analysis is documented and preliminary data is shown to demonstrate the capability of the experiment to produce high-fidelity datasets for advanced combustion research. Building on this experimental infrastructure, simultaneous measurements of velocity and scalar fields were performed in turbulent nonpremixed flames at gas turbine engine operating conditions using 5 kHz Particle-Image Velocimetry (PIV) and OH Planar Laser Induced Fluorescence (OH-PLIF). The experimental systems and the challenges associated with acquiring useful data at high pressures and high thermal powers are discussed. The quality of the particle scattering images used in the two-dimensional, two-component velocity field measurements is discussed. The effects of high flame luminosity and particle defocusing on the signal-to-noise ratio are discussed. Laser sheet absorption effects, which have been reported to be severe in many previous high pressure OH-PLIF attempts, were not observed to be significant in this work. The time-averaged peak and (spatial) mean signal to noise ratios were 12.7 and 6.3, respectively, at the flame B operating condition; 550 kW total thermal power and 1.0 MPa combustion chamber pressure. Simultaneous 5 kHz PIV and OH-PLIF measurements showed good agreement between single-shot flow-flame interactions, but unresolved, out-of-plane velocity components restricted the interpretation of the temporal context. At a 5 kHz interrogation frequency, the temporal resolution of the measurements was found to be sufficient for only the largest scales within the turbulent flame. The development of an analysis library for the extraction of physical data from highly-resolved planar measurements is also described. The resolution of the measurements, in space and time, is described with respect to the integral scales of the flow. The mean flow structure and its resultant effect on flame behavior is discussed. A method to perform mass-weighted averaging of flow variables was developed for direct comparison of turbulent flow properties between experimental measurements and computations. Conditional statistical sampling and length-scale filtering were used to elucidate details of flow-flame interactions as they pertain to sub-grid modeling in large-eddy simulations.

Validation of Multi-Dimensional Stirling Engine Design Codes: Measurements in the 90-Degree Turn Test Section

NASA Technical Reports Server (NTRS)

Simon, Terrence W.; Adolfson, David

2006-01-01

The work to be presented herein was motivated largely by a desire to improve the understanding of oscillatory fluid mechanics inside a Stirling engine. To this end, a CFD project was undertaken at Cleveland State University with the goal of accurately predicting the fluid dynamics within an engine or engine component. Along with the CFD efforts, a code validation project was undertaken at the University of Minnesota. The material covered herein consists of four main parts. In section 1, an experimental investigation of a small aspect ratio impinging jet is discussed. Included in this discussion is a description of the test facilities and instrumentation. A presentation of the collected data is given and comments are made. Next, in section 2, a parallel experimental investigation is presented in which the same geometry as that of section 1 is used, but the flow conditions are changed from steady unidirectional flow to sinusoidally oscillating flow. In section Two, collected data are presented and comments are made. In section 3, a comparison is made between the results of sections 1 and 2, namely, sinusoidally oscillating flow results are compared to steady, unidirectional flow results from the same geometry. Finally, in section 4, a comparison is made between experimentally collected data (the main subject of this work) and CFD generated results. Furthermore, in appendix A, an introductory description of the primary measurement tool used in the experimental process the hot wire anemometer is given for the unfamiliar. The anemometer calibration procedure is described in appendix B. A portfolio of data reduction and data processing codes is provided in appendix C and lastly, a DVD and a roadmap of its contents is provided in an appendix D. 1.0 Unidirectional Flow Investigations 1.1 Introduction This unidirectional experimental program was undertaken to complement an oscillatory flow investigation conducted at the University of Minnesota. The oscillatory investigation is discussed thoroughly in section 2. We defer the description of the motivation behind these experiments until the introduction of section 2. The work that is discussed in this thesis began (chronologically) with oscillatory flow visualization experiments. It was decided that it would be valuable and important to investigate the flow under unidirectional conditions in the same geometry as that of the oscillatory experiments. The thought was that the unidirectional case would be less complicated to model with a CFD program (a moving boundary would be replaced with a steady state boundary condition). Thus, a series of unidirectional experiments were carried out to capture the important features of the flow within the test section. The purpose of these experiments was to provide a data set for comparison to CFD generated velocity fields. Hot-wire anemometry data were taken and flow visualization was conducted as a standard for code validation. The flow geometry was simple, such that it could be easily gridded in a CFD program. However, the geometry provided separation and transition zones, shear layers and recirculation zones. These characteristics made the flow complex and challenging for CFD computation. We comment that the order of experiments that produced this report is as follows: experimental flow visualization under oscillatory flow conditions was carried out; this was followed by unidirectional flow visualization and hot wire anemometry; finally, oscillatory hot wire anemometry was conducted. We present the results out of chronological order for the following reason: the unidirectional results are easier

Adaptive landscapes: Top-down and bottom-up perspectives

NASA Astrophysics Data System (ADS)

Kerr, Benjamin

Sewall Wright introduced the metaphor of the adaptive landscape, a map from genotype to fitness, more than 80 years ago to help describe his view of adaptive evolution. This metaphor has been immensely popular and has been used in a variety of incarnations. However, a systematic study of the genotype-fitness map presents significant problems. The space of possible genotypes is vast, and the mapping is likely dependent on both environment and the composition of genotypes in a population. In this talk, I will discuss some of these problems and present experimental strategies for uncovering features of adaptive landscapes. In particular, I will discuss how population structure can be used as an experimental variable to elucidate landscape topography and how a combination of experimental evolution and genetic engineering can reveal important landscape features in changing environments. I will also present some potential applications of this work to the problem of antibiotic resistance and potential implications for evolutionary rescue in the face of global climate change. For some of these topics, the classic notion of the adaptive landscape must itself be adapted; however, I propose that there are fruitful ways to continue to apply this metaphor.

Computational Analyses in Support of Sub-scale Diffuser Testing for the A-3 Facility. Part 3; Aero-Acoustic Analyses and Experimental Validation

NASA Technical Reports Server (NTRS)

Allgood, Daniel C.; Graham, Jason S.; McVay, Greg P.; Langford, Lester L.

2008-01-01

A unique assessment of acoustic similarity scaling laws and acoustic analogy methodologies in predicting the far-field acoustic signature from a sub-scale altitude rocket test facility at the NASA Stennis Space Center was performed. A directional, point-source similarity analysis was implemented for predicting the acoustic far-field. In this approach, experimental acoustic data obtained from "similar" rocket engine tests were appropriately scaled using key geometric and dynamic parameters. The accuracy of this engineering-level method is discussed by comparing the predictions with acoustic far-field measurements obtained. In addition, a CFD solver was coupled with a Lilley's acoustic analogy formulation to determine the improvement of using a physics-based methodology over an experimental correlation approach. In the current work, steady-state Reynolds-averaged Navier-Stokes calculations were used to model the internal flow of the rocket engine and altitude diffuser. These internal flow simulations provided the necessary realistic input conditions for external plume simulations. The CFD plume simulations were then used to provide the spatial turbulent noise source distributions in the acoustic analogy calculations. Preliminary findings of these studies will be discussed.

Information flow dynamics in the brain

NASA Astrophysics Data System (ADS)

Rabinovich, Mikhail I.; Afraimovich, Valentin S.; Bick, Christian; Varona, Pablo

2012-03-01

Timing and dynamics of information in the brain is a hot field in modern neuroscience. The analysis of the temporal evolution of brain information is crucially important for the understanding of higher cognitive mechanisms in normal and pathological states. From the perspective of information dynamics, in this review we discuss working memory capacity, language dynamics, goal-dependent behavior programming and other functions of brain activity. In contrast with the classical description of information theory, which is mostly algebraic, brain flow information dynamics deals with problems such as the stability/instability of information flows, their quality, the timing of sequential processing, the top-down cognitive control of perceptual information, and information creation. In this framework, different types of information flow instabilities correspond to different cognitive disorders. On the other hand, the robustness of cognitive activity is related to the control of the information flow stability. We discuss these problems using both experimental and theoretical approaches, and we argue that brain activity is better understood considering information flows in the phase space of the corresponding dynamical model. In particular, we show how theory helps to understand intriguing experimental results in this matter, and how recent knowledge inspires new theoretical formalisms that can be tested with modern experimental techniques.

Practical use of a framework for network science experimentation

NASA Astrophysics Data System (ADS)

Toth, Andrew; Bergamaschi, Flavio

2014-06-01

In 2006, the US Army Research Laboratory (ARL) and the UK Ministry of Defence (MoD) established a collaborative research alliance with academia and industry, called the International Technology Alliance (ITA)1 In Network and Information Sciences, to address fundamental issues concerning Network and Information Sciences that will enhance decision making for coalition operations and enable rapid, secure formation of ad hoc teams in coalition environments and enhance US and UK capabilities to conduct coalition warfare. Research conducted under the ITA was extended through collaboration between ARL and IBM UK to characterize and dene a software stack and tooling that has become the reference framework for network science experimentation in support for validation of theoretical research. This paper discusses the composition of the reference framework for experimentation resulting from the ARL/IBM UK collaboration and its use, by the Network Science Collaborative Technology Alliance (NS CTA)2 , in a recent network science experiment conducted at ARL. It also discusses how the experiment was modeled using the reference framework, the integration of two new components, the Apollo Fact-Finder3 tool and the Medusa Crowd Sensing4 application, the limitations identified and how they shall be addressed in future work.

Different views on ethics: how animal ethics is situated in a committee culture.

PubMed

Ideland, M

2009-04-01

Research that includes non-human animal experimentation is fundamentally a dilemmatic enterprise. Humans use other animals in research to improve life for their own species. Ethical principles are established to deal with this dilemma. But despite this ethical apparatus, people who in one way or another work with animal experimentation have to interpret and understand the principles from their individual points of view. In interviews with members of Swedish animal ethics committees, different views on what the term ethics really means were articulated. For one member, the difficult ethical dilemma of animal experimentation is the lack of enriched cages for mice. For another, the ethical problem lies in regulations restraining research. A third member talks about animals' right not to be used for human interests. These different views on "ethics" intersect once a month in the animal ethics committee meetings. There is no consensus on what constitutes the ethical problem that the members should be discussing. Therefore, personal views on what ethics means, and hierarchies among committee members, characterise the meetings. But committee traditions and priorities of interpretation as well are important to the decisions. The author discusses how "ethics" becomes situated and what implications this may have for committees' decisions.

DNA in the material world: electrical properties and nano-applications.

PubMed

Triberis, Georgios P; Dimakogianni, Margarita

2009-01-01

Contradictory experimental findings and theoretical interpretations have spurred intense debate over the electrical properties of the DNA double helix. In the present review article the various factors responsible for these divergences are discussed. The enlightenment of this issue could improve long range chemistry of oxidative DNA damage and repair processes, monitoring protein-DNA interactions and possible applications in nano-electronic circuit technology. The update experimental situation concerning measurements of the electrical conductivity is given. The character of the carriers responsible for the electrical conductivity measured in DNA is investigated. A theoretical model for the temperature dependence of the electrical conductivity of DNA is presented, based on microscopic models and percolation theoretical arguments. The theoretical results, excluding or including correlation effects, are applied to recent experimental findings for DNA, considering it as a one dimensional molecular wire. The results indicate that correlation effects are probably responsible for large hopping distances in DNA samples. Other theoretical conductivity models proposed for the interpretation of the responsible transport mechanism are also reviewed. Some of the most known and pioneering works on DNA's nano-applications, future developments and perspectives along with current technological limitations and patents are presented and discussed.

Copper-Substituted Lead Perovskite Materials Constructed with Different Halides for Working (CH3NH3)2CuX4-Based Perovskite Solar Cells from Experimental and Theoretical View.

PubMed

Elseman, Ahmed Mourtada; Shalan, Ahmed Esmail; Sajid, Sajid; Rashad, Mohamed Mohamed; Hassan, Ali Mostafa; Li, Meicheng

2018-04-11

Toxicity and chemical instability issues of halide perovskites based on organic-inorganic lead-containing materials still remain as the main drawbacks for perovskite solar cells (PSCs). Herein, we discuss the preparation of copper (Cu)-based hybrid materials, where we replace lead (Pb) with nontoxic Cu metal for lead-free PSCs, and investigate their potential toward solar cell applications based on experimental and theoretical studies. The formation of (CH 3 NH 3 ) 2 CuX 4 [(CH 3 NH 3 ) 2 CuCl 4 , (CH 3 NH 3 ) 2 CuCl 2 I 2 , and (CH 3 NH 3 ) 2 CuCl 2 Br 2 ] was discussed in details. Furthermore, it was found that chlorine (Cl - ) in the structure is critical for the stabilization of the formed compounds. Cu-based perovskite-like materials showed attractive absorbance features extended to the near-infrared range, with appropriate band gaps. Green photoluminescence of these materials was obtained because of Cu + ions. The power conversion efficiency was measured experimentally and estimated theoretically for different architectures of solar cell devices.

Inclusion of quasi-experimental studies in systematic reviews of health systems research.

PubMed

Rockers, Peter C; Røttingen, John-Arne; Shemilt, Ian; Tugwell, Peter; Bärnighausen, Till

2015-04-01

Systematic reviews of health systems research commonly limit studies for evidence synthesis to randomized controlled trials. However, well-conducted quasi-experimental studies can provide strong evidence for causal inference. With this article, we aim to stimulate and inform discussions on including quasi-experiments in systematic reviews of health systems research. We define quasi-experimental studies as those that estimate causal effect sizes using exogenous variation in the exposure of interest that is not directly controlled by the researcher. We incorporate this definition into a non-hierarchical three-class taxonomy of study designs - experiments, quasi-experiments, and non-experiments. Based on a review of practice in three disciplines related to health systems research (epidemiology, economics, and political science), we discuss five commonly used study designs that fit our definition of quasi-experiments: natural experiments, instrumental variable analyses, regression discontinuity analyses, interrupted times series studies, and difference studies including controlled before-and-after designs, difference-in-difference designs and fixed effects analyses of panel data. We further review current practices regarding quasi-experimental studies in three non-health fields that utilize systematic reviews (education, development, and environment studies) to inform the design of approaches for synthesizing quasi-experimental evidence in health systems research. Ultimately, the aim of any review is practical: to provide useful information for policymakers, practitioners, and researchers. Future work should focus on building a consensus among users and producers of systematic reviews regarding the inclusion of quasi-experiments. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The trials and tribulations of a practitioner-researcher: challenges and lessons learned through testing a feminist-cognitive-relational social work model of practice.

PubMed

Dombo, Eileen A; Bass, Ami P

2014-01-01

In practice with adult women who survived childhood sexual abuse, the field of social work currently lacks an evidence-based intervention. The current interventions, from the 1990s, come primarily from psychologists. The hypothesis that the Feminist-Cognitive-Relational Social Work Model and Intervention will be more effective in decreasing cognitive distortions, and increasing intimacy and relational health when compared to the standard agency intervention was tested in a quasi-experimental study. The challenges in carrying out the study in small, non-profit organizations are explored to highlight the difficulties in developing evidence-based interventions. Changes to implementation that resulted from the research findings are discussed.

Propagation effects for land mobile satellite systems: Overview of experimental and modeling results

NASA Technical Reports Server (NTRS)

Goldhirsh, Julius; Vogel, Wolfhard J.

1992-01-01

Models developed and experiments performed to characterize the propagation environment associated with land mobile communication using satellites are discussed. Experiments were carried out with transmitters on stratospheric balloons, remotely piloted aircraft, helicopters, and geostationary satellites. This text is comprised of compiled experimental results for the expressed use of communications engineers, designers of planned Land Mobile Satellite Systems (LMSS), and modelers of propagation effects. The results presented here are mostly derived from systematic studies of propagation effects for LMSS geometries in the United States associated with rural and suburban regions. Where applicable, the authors also draw liberally from the results of other related investigations in Canada, Europe, and Australia. Frequencies near 1500 MHz are emphasized to coincide with frequency bands allocated for LMSS by the International Telecommunication Union, although earlier experimental work at 870 MHz is also included.

Experimental analysis of Nd-YAG laser cutting of sheet materials - A review

NASA Astrophysics Data System (ADS)

Sharma, Amit; Yadava, Vinod

2018-01-01

Cutting of sheet material is considered as an important process due to its relevance among products of everyday life such as aircrafts, ships, cars, furniture etc. Among various sheet cutting processes (ASCPs), laser beam cutting is one of the most capable ASCP to create complex geometries with stringent design requirements in difficult-to-cut sheet materials. Based on the recent research work in the area of sheet cutting, it is found that the Nd-YAG laser is used for cutting of sheet material in general and reflective sheet material in particular. This paper reviews the experimental analysis of Nd-YAG laser cutting process, carried out to study the influence of laser cutting parameters on the process performance index. The significance of experimental modeling and different optimization approaches employed by various researchers has also been discussed in this study.

Historical review of missile aerodynamic developments

NASA Technical Reports Server (NTRS)

Spearman, M. Leroy

1989-01-01

The development of missiles from early history up to about 1970 is discussed. Early unpowered missiles beyond the rock include the spear, the bow and arrow, the gun and bullet, and the cannon and projectile. Combining gunpowder with projectiles resulted in the first powered missiles. In the early 1900's, the development of guided missiles was begun. Significant advances in missile technology were made by German scientists during World War II. The dispersion of these advances to other countries following the war resulted in accelerating the development of guided missiles. In the late 1940's and early 1950's there was a proliferation in the development of missile systems in many countries. These developments were based primarily on experimental work and on relatively crude analytical techniques. Discussed here are some of the missile systems that were developed up to about 1970; some of the problems encountered; the development of an experimental data base for use with missiles; and early efforts to develop analytical methods applicable to missiles.

Issues in Turbulence Simulation for Experimental Comparison

NASA Astrophysics Data System (ADS)

Ross, D. W.; Bravenec, R. V.; Dorland, W.; Beer, M. A.; Hammett, G. W.

1999-11-01

Studies of the sensitivity of fluctuation spectra and transport fluxes to local plasma parameters and gradients(D. W. Ross et al.), Bull. Am. Phys. Soc. 43, 1760 (1998); D. W. Ross et al., Transport Task Force Workshop, Portland, Oregon, (1999). are continued using nonlinear gyrofluid simulation(M. A. Beer et al.), Phys. Plasmas 2, 2687 (1995). on the T3E at NERSC. Parameters that are characteristic of discharges in DIII-D and Alcator C-Mod are employed. In the previous work, the gradients of Z_eff, n_e, and Te were varied within the experimental uncertainty. Amplitudes and fluxes are quite sensitive to dZ_eff/dr. Here, these studies are continued and extended to variation of other parameters, including T_e/T_i, and dT_i/dr, which are important for ion temperature gradient modes. The role of electric field shear is discussed. Implications for comparison with experiment, including transient perturbations, are discussed, with the goal of quantifying the accuracy of profile data needed to verify the turbulence theory.

Vortex/boundary-layer interactions: Data report, volume 1

NASA Technical Reports Server (NTRS)

Cutler, A. D.; Bradshaw, P.

1987-01-01

This report summarizes the work done under NASA Grant NAGw-581, Vortex/Boundary Layer Interactions. The experimental methods are discussed in detail and numerical results are presented, but are not fully interpreted. This report should be useful to anyone who wishes to make further use of the data (available on floppy disc or magnetic tape) for the development of turbulence models or the validation of predictive methods. Journal papers are in course of preparation.

Aqua-vanadyl ion interaction with Nafion® membranes

DOE PAGES

Vijayakumar, Murugesan; Govind, Niranjan; Li, Bin; ...

2015-03-23

Lack of comprehensive understanding about the interactions between Nafion membrane and battery electrolytes prevents the straightforward tailoring of optimal materials for redox flow battery applications. In this work, we analyzed the interaction between aqua-vanadyl cation and sulfonic sites within the pores of Nafion membranes using combined theoretical and experimental X-ray spectroscopic methods. Molecular level interactions, namely, solvent share and contact pair mechanisms are discussed based on Vanadium and Sulfur K-edge spectroscopic analysis.

Theoretical and experimental study on reabsorption effect and temperature characteristic of a quasi-three-level 946nm Nd:YAG laser

NASA Astrophysics Data System (ADS)

Huang, Jing; Wan, Yuan; Chen, Weibiao

2015-02-01

The influence of temperature and incident pump power on reabsorption loss is theoretically discussed. Temperature characteristic and reabsorption loss rate of a diode-pumped quasi-three-level 946 nm Nd:YAG laser are investigated. Reabsorption effect has a significant impact on laser performance. The results indicate that reabsorption loss increases as the working temperature rises and decreases with the increased incident pump power.

High efficiency IR supercontinuum generation and applications

NASA Astrophysics Data System (ADS)

Yin, Stuart (Shizhuo); Ruffin, Paul; Brantley, Christina; Edwards, Eugene; Yang, Chia-En; Luo, Claire

2010-08-01

In this paper, we have reviewed our recent works on IR supercontinuum generation (SCG) and its applications. First, we provide a brief review on the physical mechanism of the supercontinuum generation. Second, the advance of SCG in single crystal sapphire fibers is reviewed and introduced. In particular, we discussed how to fabricate thinned sapphire fiber and use it for high efficiency SCG. Finally, experimental results of chemical analysis with supercontinuum source are reviewed.

Multipli-Entangled Photons from a Spontaneous Parametric Down-Conversion Source

DTIC Science & Technology

2011-01-01

Alsing, Corey J. Peters (AFRL/RITA); Enrique J. Galvez ( Colgate University, Hamilton, NY) 5d. PROJECT NUMBER QIS0 5e. TASK NUMBER PR 5f...and Enrique J. Galvez Colgate University, Hamilton, NY (USA) 1. ABSTRACT In this work, we discuss a novel compact source that generates six...single pair of entangled photons per pass in conventional SPDC-based sources. We first describe the experimental testbed used for evaluation and

Error enhancement in geomagnetic models derived from scalar data

NASA Technical Reports Server (NTRS)

Stern, D. P.; Bredekamp, J. H.

1975-01-01

An investigation conducted by Backus (1970) regarding the possible existence of two harmonic functions of certain characteristics in three-dimensional space is considered. The derivation of a model of the main geomagnetic field from scalar data is discussed along with a numerical simulation study. It is found that experimental discrepancies between vector field observations and the predictions of the model may have a mathematical origin, related to the work of Backus.

Strategies for "wiring" redox-active proteins to electrodes and applications in biosensors, biofuel cells, and nanotechnology.

PubMed

Nöll, Tanja; Nöll, Gilbert

2011-07-01

In this tutorial review the basic approaches to establish electrochemical communication between redox-active proteins and electrodes are elucidated and examples for applications in electrochemical biosensors, biofuel cells and nanotechnology are presented. The early stage of protein electrochemistry is described giving a short overview over electron transfer (ET) between electrodes and proteins, followed by a brief introduction into experimental procedures for studying proteins at electrodes and possible applications arising thereof. The article starts with discussing the electrochemistry of cytochrome c, the first redox-active protein, for which direct reversible ET was obtained, under diffusion controlled conditions and after adsorption to electrodes. Next, examples for the electrochemical study of redox enzymes adsorbed on electrodes and modes of immobilization are discussed. Shortly the experimental approach for investigating redox-active proteins adsorbed on electrodes is outlined. Possible applications of redox enzymes in electrochemical biosensors and biofuel cells working by direct ET (DET) and mediated ET (MET) are presented. Furthermore, the reconstitution of redox active proteins at electrodes using molecular wire-like units in order to "wire" the proteins to the electrode surface and possible applications in nanotechnology are discussed.

Defects and Small Polarons on Oxide Surfaces

NASA Astrophysics Data System (ADS)

Janotti, Anderson

The presence and behavior of defects on the surface of oxides are central in many research areas, including catalysis, photochemistry, solar cells, and surface science in general. Experimental characterization of individual defects and their activities are challenging and often requires special preparations of the surface. First-principles calculations based on density functional theory are a powerful tool to study surfaces and defects, often providing information on properties that are difficult to access experimentally. Here we discuss the behavior of defects on oxide surfaces from the perspective on first-principles calculations. We use the oxygen vacancy on TiO2 surface as example, a system that has been extensively reported in the literature. Using DFT with a hybrid function, we discuss surface states induced by the defect and localization of the excess charge in the form of small polarons. We then discuss the effects of hydrogen and compare the behavior of these defects on the surface with that in the bulk. We also compare our recent results with previous theoretical studies and experiments. Finally, we generalize the findings on TiO2 to the surfaces of other oxides. This work was supported by the NSF.

Physical principles of intracellular organization via active and passive phase transitions

NASA Astrophysics Data System (ADS)

Berry, Joel; Brangwynne, Clifford P.; Haataja, Mikko

2018-04-01

Exciting recent developments suggest that phase transitions represent an important and ubiquitous mechanism underlying intracellular organization. We describe key experimental findings in this area of study, as well as the application of classical theoretical approaches for quantitatively understanding these data. We also discuss the way in which equilibrium thermodynamic driving forces may interface with the fundamentally out-of-equilibrium nature of living cells. In particular, time and/or space-dependent concentration profiles may modulate the phase behavior of biomolecules in living cells. We suggest future directions for both theoretical and experimental work that will shed light on the way in which biological activity modulates the assembly, properties, and function of viscoelastic states of living matter.

Observation of extremely strong shock waves in solids launched by petawatt laser heating

DOE PAGES

Lancaster, K. L.; Robinson, A. P. L.; Pasley, J.; ...

2017-08-25

Understanding hydrodynamic phenomena driven by fast electron heating is important for a range of applications including fast electron collimation schemes for fast ignition and the production and study of hot, dense matter. In this work, detailed numerical simulations modelling the heating, hydrodynamic evolution, and extreme ultra-violet (XUV) emission in combination with experimental XUV images indicate shock waves of exceptional strength (200 Mbar) launched due to rapid heating of materials via a petawatt laser. In conclusion, we discuss in detail the production of synthetic XUV images and how they assist us in interpreting experimental XUV images captured at 256 eV usingmore » a multi-layer spherical mirror.« less

Hypervelocity sub 10-micron impacts into aluminium foil: new experimental data and implications for comet 81P/Wild-2's dust fluence

NASA Astrophysics Data System (ADS)

Price, Mark C.; Kearsley, Anton T.; Burchell, Mark J.; Horz, Friedrich; Cole, Mike J.

2009-06-01

Recent experimental work (Price, M. C. et. al., LPSC XXXX, #1564, 2009) has shown that the lip-to-lip diameter of hypervelocity impact craters at micron-scales (Dp< 10 microns) is a non-linear function of the impactor's diameter (Dp). We present data for monodisperse silica projectiles impacting aluminium-1100 and elemental aluminium at 6.1 kmsec and discuss the implications of this effect for the Stardust fluence calibration for micron-scale particles (which make up the majority of the impactor flux). Hydrocodes have been used to investigate the potential causes of the phenomena and the results are presented.

Accuracy of Reaction Cross Section for Exotic Nuclei in Glauber Model Based on MCMC Diagnostics

NASA Astrophysics Data System (ADS)

Rueter, Keiti; Novikov, Ivan

2017-01-01

Parameters of a nuclear density distribution for an exotic nuclei with halo or skin structures can be determined from the experimentally measured reaction cross-section. In the presented work, to extract parameters such as nuclear size information for a halo and core, we compare experimental data on reaction cross-sections with values obtained using expressions of the Glauber Model. These calculations are performed using a Markov Chain Monte Carlo algorithm. We discuss the accuracy of the Monte Carlo approach and its dependence on k*, the power law turnover point in the discreet power spectrum of the random number sequence and on the lag-1 autocorrelation time of the random number sequence.

Physical principles of intracellular organization via active and passive phase transitions.

PubMed

Berry, Joel; Brangwynne, Clifford P; Haataja, Mikko

2018-04-01

Exciting recent developments suggest that phase transitions represent an important and ubiquitous mechanism underlying intracellular organization. We describe key experimental findings in this area of study, as well as the application of classical theoretical approaches for quantitatively understanding these data. We also discuss the way in which equilibrium thermodynamic driving forces may interface with the fundamentally out-of-equilibrium nature of living cells. In particular, time and/or space-dependent concentration profiles may modulate the phase behavior of biomolecules in living cells. We suggest future directions for both theoretical and experimental work that will shed light on the way in which biological activity modulates the assembly, properties, and function of viscoelastic states of living matter.

Linear system identification via backward-time observer models

NASA Technical Reports Server (NTRS)

Juang, Jer-Nan; Phan, Minh

1993-01-01

This paper presents an algorithm to identify a state-space model of a linear system using a backward-time approach. The procedure consists of three basic steps. First, the Markov parameters of a backward-time observer are computed from experimental input-output data. Second, the backward-time observer Markov parameters are decomposed to obtain the backward-time system Markov parameters (backward-time pulse response samples) from which a backward-time state-space model is realized using the Eigensystem Realization Algorithm. Third, the obtained backward-time state space model is converted to the usual forward-time representation. Stochastic properties of this approach will be discussed. Experimental results are given to illustrate when and to what extent this concept works.

Representativeness of direct observations selected using a work-sampling equation.

PubMed

Sharp, Rebecca A; Mudford, Oliver C; Elliffe, Douglas

2015-01-01

Deciding on appropriate sampling to obtain representative samples of behavior is important but not straightforward, because the relative duration of the target behavior may affect its observation in a given sampling interval. Work-sampling methods, which offer a way to adjust the frequency of sampling according to a priori or ongoing estimates of the behavior to achieve a preselected level of representativeness, may provide a solution. Full-week observations of 7 behaviors were conducted for 3 students with autism spectrum disorder and intellectual disabilities. Work-sampling methods were used to select momentary time samples from the full time-of-interest, which produced representative samples. However, work sampling required impractically high numbers of time samples to obtain representative samples. More practical momentary time samples produced less representative samples, particularly for low-duration behaviors. The utility and limits of work-sampling methods for applied behavior analysis are discussed. © Society for the Experimental Analysis of Behavior.

Scratching the surface of ice: Interfacial phase transitions and their kinetic implications

NASA Astrophysics Data System (ADS)

Limmer, David

The surface structure of ice maintains a high degree of disorder down to surprisingly low temperatures. This is due to a number of underlying interfacial phase transitions that are associated with incremental changes in broken symmetry relative to the bulk crystal. In this talk I summarize recent work attempting to establish the nature and locations of these different phase transitions as well as how they depend on external conditions and nonequilibrium driving. The implications of this surface disorder is discussed in the context of simple kinetic processes that occur at these interfaces. Recent experimental work on the roughening transition is highlighted.

Effects of Severe Mental Illness Education on MSW Student Attitudes About Schizophrenia

PubMed Central

Eack, Shaun M.; Newhill, Christina E.; Watson, Amy C.

2013-01-01

Social work students (n = 60) in a master’s-level course on severe mental illness participated in a quasi-experimental study examining the degree to which increased knowledge about and contact with individuals with schizophrenia during the course would impact their attitudes toward people with the disorder. Results revealed significant improvement in student knowledge and general attitudes after the course, and indicated that increased knowledge about schizophrenia was only related to general attitudinal improvement when accompanied by increased personal social contact. Implications for education on severe mental illnesses, and value and attitude development in social work education are discussed PMID:24465119

Pre-equilibrium Longitudinal Flow in the IP-Glasma Framework for Pb+Pb Collisions at the LHC

NASA Astrophysics Data System (ADS)

McDonald, Scott; Shen, Chun; Fillion-Gourdeau, François; Jeon, Sangyong; Gale, Charles

2017-08-01

In this work, we debut a new implementation of IP-Glasma and quantify the pre-equilibrium longitudinal flow in the IP-Glasma framework. The saturation physics based IP-Glasma model naturally provides a non-zero initial longitudinal flow through its pre-equilibrium Yang-Mills evolution. A hybrid IP-Glasma+MUSIC+UrQMD frame-work is employed to test this new implementation against experimental data and to make further predictions about hadronic flow observables in Pb+Pb collisions at 5.02 TeV. Finally, the non-zero pre-equilibrium longitudinal flow of the IP-Glasma model is quantified, and its origin is briefly discussed.

Computational imaging with a single-pixel detector and a consumer video projector

NASA Astrophysics Data System (ADS)

Sych, D.; Aksenov, M.

2018-02-01

Single-pixel imaging is a novel rapidly developing imaging technique that employs spatially structured illumination and a single-pixel detector. In this work, we experimentally demonstrate a fully operating modular single-pixel imaging system. Light patterns in our setup are created with help of a computer-controlled digital micromirror device from a consumer video projector. We investigate how different working modes and settings of the projector affect the quality of reconstructed images. We develop several image reconstruction algorithms and compare their performance for real imaging. Also, we discuss the potential use of the single-pixel imaging system for quantum applications.

An analytical approach to test and design upper limb prosthesis.

PubMed

Veer, Karan

2015-01-01

In this work the signal acquiring technique, the analysis models and the design protocols of the prosthesis are discussed. The different methods to estimate the motion intended by the amputee from surface electromyogram (SEMG) signals based on time and frequency domain parameters are presented. The experiment proposed that the used techniques can help significantly in discriminating the amputee's motions among four independent activities using dual channel set-up. Further, based on experimental results, the design and working of an artificial arm have been covered under two constituents--the electronics design and the mechanical assembly. Finally, the developed hand prosthesis allows the amputated persons to perform daily routine activities easily.

Thermal Cycling and High Temperature Reverse Bias Testing of Control and Irradiated Gallium Nitride Power Transistors

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Boomer, Kristen T.; Scheick, Leif; Lauenstein, Jean-Marie; Casey, Megan; Hammoud, Ahmad

2014-01-01

The power systems for use in NASA space missions must work reliably under harsh conditions including radiation, thermal cycling, and exposure to extreme temperatures. Gallium nitride semiconductors show great promise, but information pertaining to their performance is scarce. Gallium nitride N-channel enhancement-mode field effect transistors made by EPC Corporation in a 2nd generation of manufacturing were exposed to radiation followed by long-term thermal cycling and testing under high temperature reverse bias conditions in order to address their reliability for use in space missions. Result of the experimental work are presented and discussed.

Beyond the hypothesis: Theory's role in the genesis, opposition, and pursuit of the Higgs boson

NASA Astrophysics Data System (ADS)

Wells, James D.

2018-05-01

The centrally recognized theoretical achievement that enabled the Higgs boson discovery in 2012 was the hypothesis of its existence, made by Peter Higgs in 1964. Nevertheless, there is a significant body of comparably important theoretical work prior to and after the Higgs boson hypothesis. In this article we present an additional perspective of how crucial theory work was to the genesis of the Higgs boson hypothesis, especially emphasizing its roots in Landau's theory of phase transitions and subsequent theoretical work on superconductivity. A detailed description is then given of the opposition to the Higgs boson hypothesis by many researchers, giving evidence to its speculative nature. And finally, it is discussed the importance of theory work in the decades after the hypothesis in order to make possible the experimental discovery of the Higgs boson.

Ethnographic study of ICT-supported collaborative work routines in general practice

PubMed Central

2010-01-01

Background Health informatics research has traditionally been dominated by experimental and quasi-experimental designs. An emerging area of study in organisational sociology is routinisation (how collaborative work practices become business-as-usual). There is growing interest in the use of ethnography and other in-depth qualitative approaches to explore how collaborative work routines are enacted and develop over time, and how electronic patient records (EPRs) are used to support collaborative work practices within organisations. Methods/design Following Feldman and Pentland, we will use 'the organisational routine' as our unit of analysis. In a sample of four UK general practices, we will collect narratives, ethnographic observations, multi-modal (video and screen capture) data, documents and other artefacts, and analyse these to map and compare the different understandings and enactments of three common routines (repeat prescribing, coding and summarising, and chronic disease surveillance) which span clinical and administrative spaces and which, though 'mundane', have an important bearing on quality and safety of care. In a detailed qualitative analysis informed by sociological theory, we aim to generate insights about how complex collaborative work is achieved through the process of routinisation in healthcare organisations. Discussion Our study offers the potential not only to identify potential quality failures (poor performance, errors, failures of coordination) in collaborative work routines but also to reveal the hidden work and workarounds by front-line staff which bridge the model-reality gap in EPR technologies and via which "automated" safety features have an impact in practice. PMID:21190583

Simulation of solid-liquid flows in a stirred bead mill based on computational fluid dynamics (CFD)

NASA Astrophysics Data System (ADS)

Winardi, S.; Widiyastuti, W.; Septiani, E. L.; Nurtono, T.

2018-05-01

The selection of simulation model is an important step in computational fluid dynamics (CFD) to obtain an agreement with experimental work. In addition, computational time and processor speed also influence the performance of the simulation results. Here, we report the simulation of solid-liquid flow in a bead mill using Eulerian model. Multiple Reference Frame (MRF) was also used to model the interaction between moving (shaft and disk) and stationary (chamber exclude shaft and disk) zones. Bead mill dimension was based on the experimental work of Yamada and Sakai (2013). The effect of shaft rotation speed of 1200 and 1800 rpm on the particle distribution and the flow field was discussed. For rotation speed of 1200 rpm, the particles spread evenly throughout the bead mill chamber. On the other hand, for the rotation speed of 1800 rpm, the particles tend to be thrown to the near wall region resulting in the dead zone and found no particle in the center region. The selected model agreed well to the experimental data with average discrepancies less than 10%. Furthermore, the simulation was run without excessive computational cost.

Architectures for Quantum Simulation Showing a Quantum Speedup

NASA Astrophysics Data System (ADS)

Bermejo-Vega, Juan; Hangleiter, Dominik; Schwarz, Martin; Raussendorf, Robert; Eisert, Jens

2018-04-01

One of the main aims in the field of quantum simulation is to achieve a quantum speedup, often referred to as "quantum computational supremacy," referring to the experimental realization of a quantum device that computationally outperforms classical computers. In this work, we show that one can devise versatile and feasible schemes of two-dimensional, dynamical, quantum simulators showing such a quantum speedup, building on intermediate problems involving nonadaptive, measurement-based, quantum computation. In each of the schemes, an initial product state is prepared, potentially involving an element of randomness as in disordered models, followed by a short-time evolution under a basic translationally invariant Hamiltonian with simple nearest-neighbor interactions and a mere sampling measurement in a fixed basis. The correctness of the final-state preparation in each scheme is fully efficiently certifiable. We discuss experimental necessities and possible physical architectures, inspired by platforms of cold atoms in optical lattices and a number of others, as well as specific assumptions that enter the complexity-theoretic arguments. This work shows that benchmark settings exhibiting a quantum speedup may require little control, in contrast to universal quantum computing. Thus, our proposal puts a convincing experimental demonstration of a quantum speedup within reach in the near term.

Molecular Dynamics Studies of Proton Transport in Hydrogenase and Hydrogenase Mimics.

PubMed

Ginovska, B; Raugei, S; Shaw, W J

2016-01-01

There is extensive interest in hydrogenases based on their ability to rapidly and efficiently interconvert H2 with protons and electrons, and their (typically) superior function relative to molecular mimics. Understanding the function of enzymes is one approach to implementing design features to make better catalysts and is an approach we have implemented in our work. In this review, we will discuss our efforts to develop design principles from enzymes, with specific focus on proton transport. We will also present computational studies of the mimics we have investigated with similar methodologies. We will discuss the mechanisms used by small scaffolds on molecular mimics which in many cases are surprisingly similar to those used by nature, while in other cases, computational analysis allowed us to reveal an unexpected role. Computational methods provide one of the best ways, and in some cases, the only way, to gain insight into the mechanistic details of enzymes. In this review, we illustrate the general computational strategy we used to study the proton pathway of [FeFe]-hydrogenase, and the similar strategy to investigate small molecules. We present the main results we obtained and how our computational work stimulated or worked in concert with experimental investigations. We also focus on estimation of errors and convergence of properties in the simulations. These studies demonstrate the powerful results that can be obtained by the close pairing of experimental and theoretical approaches. Copyright © 2016 Elsevier Inc. All rights reserved. Battelle, operator of PNNL, under Contract No: DE-AC05-76RL01830 with US DoE.

Using a Paradigm Shift to Teach Neurobiology and the Nature of Science-a C.R.E.A.T.E.-based Approach.

PubMed

Hoskins, Sally G

2008-01-01

Decades ago, classic experiments established the phenomenon of "neural induction" (Spemann and Mangold, 1924; Holtfreter, 1933). It appeared clear that amphibian ectoderm was pre-programmed to form epidermis, and that the neural phenotype was induced by a chemical signal from mesoderm. The "ectoderm makes skin, unless induced to make nervous system" model appeared in many textbooks. This interpretation, however, was not simply incorrect but 180 degrees out of alignment with the actual situation. As subsequently demonstrated, the default state of amphibian ectoderm is neuronal, and the expression of the epidermal phenotype requires cell signaling (Hemmati-Brivanlou and Melton, 1992; 1994; 1997). In this activity, students are presented with key experiments in a stepwise fashion. At several points, they work in groups to devise models that explain particular experimental results. The stepwise presentation of results mirrors the history of discoveries in this experimental system. Eventually, faced with seemingly contradictory data, students must revise their models substantially and in doing so, experience the paradigm shift. The lesson also examines the history of this paradigm shift. Data inconsistent with the "epidermal default" model were published years before the "neural default" model was proposed, but the significance of the surprising new data was underemphasized by the scientists who made the discovery. Discussing this situation provides insight into how science works and highlights the possibility that working scientists may become entrenched in prevailing paradigms. Such "nature of science" discussions emphasize research as a human activity, and help to dispel student misconceptions about science and scientists.

Techniques and Technology to Revise Content Delivery and Model Critical Thinking in the Neuroscience Classroom

PubMed Central

Illig, Kurt R.

2015-01-01

Undergraduate neuroscience courses typically involve highly interdisciplinary material, and it is often necessary to use class time to review how principles of chemistry, math and biology apply to neuroscience. Lecturing and Socratic discussion can work well to deliver information to students, but these techniques can lead students to feel more like spectators than participants in a class, and do not actively engage students in the critical analysis and application of experimental evidence. If one goal of undergraduate neuroscience education is to foster critical thinking skills, then the classroom should be a place where students and instructors can work together to develop them. Students learn how to think critically by directly engaging with course material, and by discussing evidence with their peers, but taking classroom time for these activities requires that an instructor find a way to provide course materials outside of class. Using technology as an on-demand provider of course materials can give instructors the freedom to restructure classroom time, allowing students to work together in small groups and to have discussions that foster critical thinking, and allowing the instructor to model these skills. In this paper, I provide a rationale for reducing the use of traditional lectures in favor of more student-centered activities, I present several methods that can be used to deliver course materials outside of class and discuss their use, and I provide a few examples of how these techniques and technologies can help improve learning outcomes. PMID:26240525

Techniques and Technology to Revise Content Delivery and Model Critical Thinking in the Neuroscience Classroom.

PubMed

Illig, Kurt R

2015-01-01

Undergraduate neuroscience courses typically involve highly interdisciplinary material, and it is often necessary to use class time to review how principles of chemistry, math and biology apply to neuroscience. Lecturing and Socratic discussion can work well to deliver information to students, but these techniques can lead students to feel more like spectators than participants in a class, and do not actively engage students in the critical analysis and application of experimental evidence. If one goal of undergraduate neuroscience education is to foster critical thinking skills, then the classroom should be a place where students and instructors can work together to develop them. Students learn how to think critically by directly engaging with course material, and by discussing evidence with their peers, but taking classroom time for these activities requires that an instructor find a way to provide course materials outside of class. Using technology as an on-demand provider of course materials can give instructors the freedom to restructure classroom time, allowing students to work together in small groups and to have discussions that foster critical thinking, and allowing the instructor to model these skills. In this paper, I provide a rationale for reducing the use of traditional lectures in favor of more student-centered activities, I present several methods that can be used to deliver course materials outside of class and discuss their use, and I provide a few examples of how these techniques and technologies can help improve learning outcomes.

Experimental and numerical study of control of flow separation of a symmetric airfoil with trapped vortex cavity

NASA Astrophysics Data System (ADS)

Shahid, Abdullah Bin; Mashud, Mohammad

2017-06-01

This paper summarizes the experimental campaign and numerical analysis performed aimed to analyze the potential benefit available employing a trapping vortex cell system on a high thickness symmetric aero-foil without steady suction or injection mass flow. In this work, the behavior of a two dimensional model equipped with a span wise adjusted circular cavity has been researched. Pressure distribution on the model surface and inside and the complete flow field round the model have been measured. Experimental tests have been performed varying the wind tunnel speed and also the angle of attack. For numerical analysis the two dimensional model of the airfoil and the mesh is formed through ANSYS Meshing that is run in Fluent for numerical iterate solution. In the paper the performed test campaign, the airfoil design, the adopted experimental set-up, the numerical analysis, the data post process and the results description are reported, compared a discussed.

On the assessment of biological life support system operation range

NASA Astrophysics Data System (ADS)

Bartsev, Sergey

Biological life support systems (BLSS) can be used in long-term space missions only if well-thought-out assessment of the allowable operating range is obtained. The range has to account both permissible working parameters of BLSS and the critical level of perturbations of BLSS stationary state. Direct approach to outlining the range by statistical treatment of experimental data on BLSS destruction seems to be not applicable due to ethical, economical, and saving time reasons. Mathematical model is the unique tool for the generalization of experimental data and the extrapolation of the revealed regularities beyond empirical experience. The problem is that the quality of extrapolation depends on the adequacy of corresponding model verification, but good verification requires wide range of experimental data for fitting, which is not achievable for manned experimental BLSS. Possible way to improve the extrapolation quality of inevitably poorly verified models of manned BLSS is to extrapolate general tendency obtained from unmanned LSS theoretical-experiment investigations. Possibilities and limitations of such approach are discussed.

Broadband frequency and angular response of a sinusoidal bull’s eye antenna

NASA Astrophysics Data System (ADS)

Beaskoetxea, U.; Navarro-Cía, M.; Beruete, M.

2016-07-01

A thorough experimental study of the frequency and beaming angle response of a metallic leaky-wave bull’s eye antenna working at 77 GHz with a sinusoidally corrugated profile is presented. The beam scanning property of these antennas as frequency is varied is experimentally demonstrated and corroborated through theoretical and numerical results. From the experimental results the dispersion diagram of the n  =  -1 and n  =  -2 space harmonics is extracted, and the operation at different frequency regimes is identified and discussed. In order to show the contribution of each half of the antenna, numerical examples of the near-field behavior are also displayed. Overall, experimental results are in good qualitative and quantitative agreement with theoretical and numerical calculations. Finally, an analysis of the beamwidth as a function of frequency is performed, showing that it can achieve values below 1.5° in a fractional bandwidth of 4% around the operation frequency, which is an interesting frequency-stable broadside radiation.

Research designs for studies evaluating the effectiveness of change and improvement strategies.

PubMed

Eccles, M; Grimshaw, J; Campbell, M; Ramsay, C

2003-02-01

The methods of evaluating change and improvement strategies are not well described. The design and conduct of a range of experimental and non-experimental quantitative designs are considered. Such study designs should usually be used in a context where they build on appropriate theoretical, qualitative and modelling work, particularly in the development of appropriate interventions. A range of experimental designs are discussed including single and multiple arm randomised controlled trials and the use of more complex factorial and block designs. The impact of randomisation at both group and individual levels and three non-experimental designs (uncontrolled before and after, controlled before and after, and time series analysis) are also considered. The design chosen will reflect both the needs (and resources) in any particular circumstances and also the purpose of the evaluation. The general principle underlying the choice of evaluative design is, however, simple-those conducting such evaluations should use the most robust design possible to minimise bias and maximise generalisability.

Shortcuts to Adiabaticity in Transport of a Single Trapped Ion

NASA Astrophysics Data System (ADS)

An, Shuoming; Lv, Dingshun; Campo, Adolfo Del; Kim, Kihwan

2015-05-01

We report an experimental study on shortcuts to adiabaticity in the transport of a single 171Yb+ ion trapped in a harmonic potential. In these driving schemes, the application of a force induces a nonadiabatic dynamics in which excitations are tailored so as to preserve the ion motional state in the ground state upon completion of the process. We experimentally apply the laser induced force and realize three different protocols: (1) a transitionless driving with a counterdiabatic term out of phase with the displacement force, (2) a classical protocol assisted by counterdiabatic fields in phase with the main force, (3) and an engineered transport protocol based on the Fourier transform of the trap acceleration. We experimentally compare and discuss the robustness of these protocols under given experimental limitations such as trap frequency drifts. This work was supported by the National Basic Research Program of China under Grants No. 2011CBA00300 (No. 2011CBA00301), the National Natural Science Foundation of China 11374178, and the University of Massachusetts Boston (No. P20150000029279).

Experimental and Numerical Investigation of Local Scour Around Submarine Piggyback Pipeline Under Steady Current

NASA Astrophysics Data System (ADS)

Zhao, Enjin; Shi, Bing; Qu, Ke; Dong, Wenbin; Zhang, Jing

2018-04-01

As a new type of submarine pipeline, the piggyback pipeline has been gradually adopted in engineering practice to enhance the performance and safety of submarine pipelines. However, limited simulation work and few experimental studies have been published on the scour around the piggyback pipeline under steady current. This study numerically and experimentally investigates the local scour of the piggyback pipe under steady current. The influence of prominent factors such as pipe diameter, inflow Reynolds number, and gap between the main and small pipes, on the maximum scour depth have been examined and discussed in detail. Furthermore, one formula to predict the maximum scour depth under the piggyback pipeline has been derived based on the theoretical analysis of scour equilibrium. The feasibility of the proposed formula has been effectively calibrated by both experimental data and numerical results. The findings drawn from this study are instructive in the future design and application of the piggyback pipeline.

Effects of thermal annealing and reirradiation on toughness of reactor pressure vessel steels

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

Nanstad, R.K.; Iskander, S.K.; Sokolov, M.A.

1997-02-01

One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPV) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. This paper summarizes recent experimental results from work performed at the Oak Ridge National Laboratory (ORNL) to study the annealing response, or {open_quotes}recovery,{close_quotes} of several irradiated RPV steels; it also includes recent results from both ORNL and the Russian Research Center-Kurchatov Institute (RRC-KI) on a cooperative program of irradiation, annealing and reirradiation of both U.S. and Russian RPV steels. The cooperative program was conducted under the auspices ofmore » Working Group 3, U.S./Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS). The materials investigated are an RPV plate and various submerged-arc welds, with tensile, Charpy impact toughness, and fracture toughness results variously determined. Experimental results are compared with applicable prediction guidelines, while observed differences in annealing responses and reirradiation rates are discussed.« less

Stability Limits and Dynamics of Nonaxisymmetric Liquid Bridges

NASA Technical Reports Server (NTRS)

Alexander, J. Iwan D.; Slobozhanin, Lev A.; Resnick, Andrew H.; Ramus, Jean-Francois; Delafontaine, Sylvie

1999-01-01

Liquid bridges have been the focus of numerous theoretical and experimental investigations since the early work by Plateau more than a century ago. More recently, motivated by interest in their physical behavior and their occurrence in a variety of technological situations, there has been a resurgence of interest in the static and dynamic behavior of liquid bridges. Furthermore, opportunities to carry out experiments in the near weightless environment of a low-Earth-orbit spacecraft have also led to a number of low-gravity experiments involving large liquid bridges. In this paper, we present selected results from our work concerning the stability of nonaxisymmetric liquid bridges, the bifurcation of weightless bridges in the neighborhood of the maximum volume stability limit, isorotating axisymmetric bridges contained between equidimensional disks, and bridges contained between unequal disks. For the latter, we discuss both theoretical and experimental results. Finally, we present results concerning the stability of axisymmetric equilibrium configurations for a capillary liquid partly contained in a closed circular cylinder.

Nano-Al Based Energetics: Rapid Heating Studies and a New Preparation Technique

NASA Astrophysics Data System (ADS)

Sullivan, Kyle; Kuntz, Josh; Gash, Alex; Zachariah, Michael

2011-06-01

Nano-Al based thermites have become an attractive alternative to traditional energetic formulations due to their increased energy density and high reactivity. Understanding the intrinsic reaction mechanism has been a difficult task, largely due to the lack of experimental techniques capable of rapidly and uniform heating a sample (~104- 108 K/s). The current work presents several studies on nano-Al based thermites, using rapid heating techniques. A new mechanism termed a Reactive Sintering Mechanism is proposed for nano-Al based thermites. In addition, new experimental techniques for nanocomposite thermite deposition onto thin Pt electrodes will be discussed. This combined technique will offer more precise control of the deposition, and will serve to further our understanding of the intrinsic reaction mechanism of rapidly heated energetic systems. An improved mechanistic understanding will lead to the development of optimized formulations and architectures. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

A Simple Experimental Setup for Teaching Additive Colors with Arduino

NASA Astrophysics Data System (ADS)

Carvalho, Paulo Simeão; Hahn, Marcelo

2016-04-01

The result of additive colors is always fascinating to young students. When we teach this topic to 14- to 16-year-old students, they do not usually notice we use maximum light quantities of red (R), green (G), and blue (B) to obtain yellow, magenta, and cyan colors in order to build the well-known additive color diagram of Fig. 1. But how about using different light intensities for R, G, and B? What colors do we get? This problem of color mixing has been intensively discussed for decades by several authors, as pointed out by Ruiz's "Color Addition and Subtraction Apps" work and the references included therein. An early LED demonstrator for additive color mixing dates back to 1985, and apps to illustrate color mixing are available online. In this work, we describe an experimental setup making use of a microcontroller device: the Arduino Uno. This setup is designed as a game in order to improve students' understanding of color mixing.

Experimental Study of under-platform Damper Kinematics in Presence of Blade Dynamics

NASA Astrophysics Data System (ADS)

Botto, D.; Gastaldi, C.; Gola, M. M.; Umer, M.

2018-01-01

Among the different devices used in the aerospace industries under-platform dampers are widely used in turbo engines to mitigate the blade vibration. Nevertheless, the damper behaviour is not easy to simulate and engineers have been working in order to improve the accuracy with which theoretical contact models predict the damper behaviour. Majority of the experimental setups collect experimental data in terms of blade amplitude reduction which do not increase the knowledge about the damper dynamics and therefore the uncertainty on the damper behaviour remains a big issue. In this paper, a novel test rig has been purposely designed to accommodate a single blade and two under-platform dampers to deeply investigate the damper-blade interactions. In this test bench, a contact force measuring system was designed to extensively measure the damper contact forces. Damper kinematics is rebuilt by using the relative displacement measured between damper and blade. This paper describes the concept behind the new approach, shows the details of new test rig and discusses experimental results by comparing with previously measured results on an old experimental setup.

Does safety climate moderate the influence of staffing adequacy and work conditions on nurse injuries?

PubMed

Mark, Barbara A; Hughes, Linda C; Belyea, Michael; Chang, Yunkyung; Hofmann, David; Jones, Cheryl B; Bacon, Cynthia T

2007-01-01

Hospital nurses have one of the highest work-related injury rates in the United States. Yet, approaches to improving employee safety have generally focused on attempts to modify individual behavior through enforced compliance with safety rules and mandatory participation in safety training. We examined a theoretical model that investigated the impact on nurse injuries (back injuries and needlesticks) of critical structural variables (staffing adequacy, work engagement, and work conditions) and further tested whether safety climate moderated these effects. A longitudinal, non-experimental, organizational study, conducted in 281 medical-surgical units in 143 general acute care hospitals in the United States. Work engagement and work conditions were positively related to safety climate, but not directly to nurse back injuries or needlesticks. Safety climate moderated the relationship between work engagement and needlesticks, while safety climate moderated the effect of work conditions on both needlesticks and back injuries, although in unexpected ways. DISCUSSION AND IMPACT ON INDUSTRY: Our findings suggest that positive work engagement and work conditions contribute to enhanced safety climate and can reduce nurse injuries.

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

Andronov, V.A.; Zhidov, I.G.; Meskov, E.E.

This report describes an extensive program of investigations conducted at Arzamas-16 in Russia over the past several decades. The focus of the work is on material interface instability and the mixing of two materials. Part 1 of the report discusses analytical and computational studies of hydrodynamic instabilities and turbulent mixing. The EGAK codes are described and results are illustrated for several types of unstable flow. Semiempirical turbulence transport equations are derived for the mixing of two materials, and their capabilities are illustrated for several examples. Part 2 discusses the experimental studies that have been performed to investigate instabilities and turbulentmore » mixing. Shock-tube and jelly techniques are described in considerable detail. Results are presented for many circumstances and configurations.« less

Smart sensorless prediction diagnosis of electric drives

NASA Astrophysics Data System (ADS)

Kruglova, TN; Glebov, NA; Shoshiashvili, ME

2017-10-01

In this paper, the discuss diagnostic method and prediction of the technical condition of an electrical motor using artificial intelligent method, based on the combination of fuzzy logic and neural networks, are discussed. The fuzzy sub-model determines the degree of development of each fault. The neural network determines the state of the object as a whole and the number of serviceable work periods for motors actuator. The combination of advanced techniques reduces the learning time and increases the forecasting accuracy. The experimental implementation of the method for electric drive diagnosis and associated equipment is carried out at different speeds. As a result, it was found that this method allows troubleshooting the drive at any given speed.

Surface roughness influences on the behaviour of flow inside microchannels

NASA Astrophysics Data System (ADS)

Farias, M. H.; Castro, C. S.; Garcia, D. A.; Henrique, J. S.

2018-03-01

This work discusses influence of the surface roughness on the behavior of liquids flowing inside microchannels. By measuring the flow profile using the micro-PIV technique, the flow of water inside two rectangular microchannels of different wall roughness and in a circular smooth microchannel was studied. Comparisons were made among the experimental results, showing that a metrological approach concerning surface characteristics of microdevices is required to ensure reliability of the measurements for flow analyses in microfluidic processes.

Comments on theoretical foundation of "EM Drive"

NASA Astrophysics Data System (ADS)

Wu, C.-W.

2018-03-01

The concept of EM Drive has attracted much attention and groups of work have been conducted to prove or verify it, of which the published experimental outcome is criticized in great details while the theoretical foundation has not been discussed. The present essay investigates on the theoretical derivations of the net thrust in the "EM drive" and reveals the self-contradiction arising at the very start, when the law of conservation of momentum was utilized and opposed simultaneously.

Enhanced Photoresponse in Metasurface-Integrated Organic Photodetectors.

PubMed

Xu, Xin; Kwon, Hoyeong; Gawlik, Brian; Mohammadi Estakhri, Nasim; Alù, Andrea; Sreenivasan, S V; Dodabalapur, Ananth

2018-06-13

In this work, we experimentally demonstrate metasurface-enhanced photoresponse in organic photodetectors. We have designed and integrated a metasurface with broadband functionality into an organic photodetector, with the goal of significantly increasing the absorption of light and generated photocurrent from 560 up to 690 nm. We discuss how the metasurface can be integrated with the fabrication of an organic photodiode. Our results show large gains in responsivity from 1.5× to 2× between 560 and 690 nm.

Planned experiments and corpus based research play a complementary role. Comment on "Dependency distance: A new perspective on syntactic patterns in natural languages" by Haitao Liu et al.

NASA Astrophysics Data System (ADS)

Vasishth, Shravan

2017-07-01

This interesting and informative review by Liu and colleagues [17] in this issue covers the full spectrum of research on the idea that in natural language, dependency distance tends to be small. The authors discuss two distinct research threads: experimental work from psycholinguistics on online processes in comprehension and production, and text-corpus studies of dependency length distributions.

EMMA, a Recoil Mass Spectrometer for TRIUMF's ISAC-II Facility

NASA Astrophysics Data System (ADS)

Davids, Barry; EMMA Collaboration

2016-09-01

EMMA is a recoil mass spectrometer for TRIUMF's ISAC-II facility in the final stages of installation and commissioning. In this talk I will briefly review the spectrometer's design capabilities, describe recent progress in its installation and commissioning, and discuss plans for its initial experimental program. This work was supported by the Natural Sciences and Engineering Council of Canada. TRIUMF receives federal funds through a contribution agreement with the National Research Council of Canada.

Analysis of transverse field distributions in Porro prism resonators

NASA Astrophysics Data System (ADS)

Litvin, Igor A.; Burger, Liesl; Forbes, Andrew

2007-05-01

A model to describe the transverse field distribution of the output beam from porro prism resonators is proposed. The model allows the prediction of the output transverse field distribution by assuming that the main areas of loss are located at the apexes of the porro prisms. Experimental work on a particular system showed some interested correlations between the time domain behavior of the resonator and the transverse field output. These findings are presented and discussed.

Quartz Crystal Microbalance Based System for High-Sensitivity Differential Sputter Yield Measurements (Preprint)

DTIC Science & Technology

2009-08-20

at low ion energies require appropriate ion sources. For example, past work using QCM sensors employed a magnetron as an ion source 32,33 . The...and for data logging. Detailed discussion of the QCM sensor is provided in Section IID. Figure 1. Schematic diagram of the experimental set-up...mass flow rate of 0.5 sccm. The PBN was biased negatively relative to ground potential. D. QCM Sensor and Temperature Control In deposition mode

The fundamental surface science of wurtzite gallium nitride

NASA Astrophysics Data System (ADS)

Bermudez, V. M.

2017-09-01

A review is presented that covers the experimental and theoretical literature relating to the preparation, electronic structure and chemical and physical properties of the surfaces of the wurtzite form of GaN. The discussion includes the adsorption of various chemical elements and of inorganic, organometallic and organic species. The focus is on work that contributes to a microscopic, atomistic understanding of GaN surfaces and interfaces, and the review concludes with an assessment of possible future directions.

Empowering nurses for work engagement and health in hospital settings.

PubMed

Laschinger, Heather K Spence; Finegan, Joan

2005-10-01

Employee empowerment has become an increasingly important factor in determining employee health and wellbeing in restructured healthcare settings. The authors tested a theoretical model which specified the relationships among structural empowerment, 6 areas of worklife that promote employee engagement, and staff nurses' physical and mental health. A predictive, non-experimental design was used to test the model in a random sample of staff nurses. The authors discuss their findings and the implication for nurse administrators.

Delivering Integrated Care to the Frail Elderly: The Impact on Professionals’ Objective Burden and Job Satisfaction

PubMed Central

Huijsman, Robbert; de Kuyper, Ruben Dennis Maurice; Fabbricotti, Isabelle Natalina

2016-01-01

Background: The impact of integrated working on professionals’ objective burden and job satisfaction was examined. An evidence-based intervention targeting frail elderly patients was implemented in the Walcheren region of the Netherlands in 2010. The intervention involved the primary care practice as a single entry point, and included proactive frailty screening, a comprehensive assessment of patient needs, case management, multidisciplinary teams, care plans and protocols, task delegation and task specialisation, a shared information system, a geriatric care network and integrated funding. Methods: A quasi-experimental design with a control group was used. Data regarding objective burden involved the professionals’ time investments over a 12-month period that were collected from patient medical records (n = 377) time registrations, transcripts of meetings and patient questionnaires. Data regarding job satisfaction were collected using questionnaires that were distributed to primary care and home-care professionals (n = 180) after the intervention’s implementation. Within- and between-groups comparisons and regression analyses were performed. Results: Non-patient related time was significantly higher in the experimental group than in the control group, whereas patient-related time did not differ. Job satisfaction remained unaffected by the intervention. Conclusion and Discussion: Integrated working is likely to increase objective burden as it requires professionals to perform additional activities that are largely unrelated to actual patient care. Implications for research and practice are discussed. [Current Controlled Trials ISRCTN05748494]. PMID:28413364

Co-Creating the Cities of the Future

PubMed Central

Gutiérrez, Verónica; Theodoridis, Evangelos; Mylonas, Georgios; Shi, Fengrui; Adeel, Usman; Diez, Luis; Amaxilatis, Dimitrios; Choque, Johnny; Camprodom, Guillem; McCann, Julie; Muñoz, Luis

2016-01-01

In recent years, the evolution of urban environments, jointly with the progress of the Information and Communication sector, have enabled the rapid adoption of new solutions that contribute to the growth in popularity of Smart Cities. Currently, the majority of the world population lives in cities encouraging different stakeholders within these innovative ecosystems to seek new solutions guaranteeing the sustainability and efficiency of such complex environments. In this work, it is discussed how the experimentation with IoT technologies and other data sources form the cities can be utilized to co-create in the OrganiCity project, where key actors like citizens, researchers and other stakeholders shape smart city services and applications in a collaborative fashion. Furthermore, a novel architecture is proposed that enables this organic growth of the future cities, facilitating the experimentation that tailors the adoption of new technologies and services for a better quality of life, as well as agile and dynamic mechanisms for managing cities. In this work, the different components and enablers of the OrganiCity platform are presented and discussed in detail and include, among others, a portal to manage the experiment life cycle, an Urban Data Observatory to explore data assets, and an annotations component to indicate quality of data, with a particular focus on the city-scale opportunistic data collection service operating as an alternative to traditional communications. PMID:27886069

Co-Creating the Cities of the Future.

PubMed

Gutiérrez, Verónica; Theodoridis, Evangelos; Mylonas, Georgios; Shi, Fengrui; Adeel, Usman; Diez, Luis; Amaxilatis, Dimitrios; Choque, Johnny; Camprodom, Guillem; McCann, Julie; Muñoz, Luis

2016-11-23

In recent years, the evolution of urban environments, jointly with the progress of the Information and Communication sector, have enabled the rapid adoption of new solutions that contribute to the growth in popularity of Smart Cities. Currently, the majority of the world population lives in cities encouraging different stakeholders within these innovative ecosystems to seek new solutions guaranteeing the sustainability and efficiency of such complex environments. In this work, it is discussed how the experimentation with IoT technologies and other data sources form the cities can be utilized to co-create in the OrganiCity project, where key actors like citizens, researchers and other stakeholders shape smart city services and applications in a collaborative fashion. Furthermore, a novel architecture is proposed that enables this organic growth of the future cities, facilitating the experimentation that tailors the adoption of new technologies and services for a better quality of life, as well as agile and dynamic mechanisms for managing cities. In this work, the different components and enablers of the OrganiCity platform are presented and discussed in detail and include, among others, a portal to manage the experiment life cycle, an Urban Data Observatory to explore data assets, and an annotations component to indicate quality of data, with a particular focus on the city-scale opportunistic data collection service operating as an alternative to traditional communications.

Liquid droplet radiator development status

NASA Technical Reports Server (NTRS)

White, K. Alan, III

1987-01-01

Development of the Liquid Droplet Radiator (LDR) is described. Significant published results of previous investigators are presented, and work currently in progress is discussed. Several proposed LDR configurations are described, and the rectangular and triangular configurations currently of most interest are examined. Development of the droplet generator, collector, and auxiliary components are discussed. Radiative performance of a droplet sheet is considered, and experimental results are seen to be in very good agreement with analytical predictions. The collision of droplets in the droplet sheet, the charging of droplets by the space plasma, and the effect of atmospheric drag on the droplet sheet are shown to be of little consequence, or can be minimized by proper design. The LDR is seen to be less susceptible than conventional technology to the effects of micrometeoroids or hostile threats. The identification of working fluids which are stable in the orbital environments of interest is also made. Methods for reducing spacecraft contamination from an LDR to an acceptable level are discussed. Preliminary results of microgravity testing of the droplet generator are presented. Possible future NASA and Air Force missions enhanced or enabled by a LDR are also discussed. System studies indicate that the LDR is potentially less massive than heat pipe radiators. Planned microgravity testing aboard the Shuttle or space station is seen to be a logical next step in LDR development.

Natural dye extracted from karkadah and its application in dye-sensitized solar cells: experimental and density functional theory study.

PubMed

Reda, S M; Soliman, K A

2016-02-01

This work presents an experimental and theoretical study of cyanidin natural dye as a sensitizer for ZnO dye-sensitized solar cells. ZnO nanoparticles were prepared using ammonia and oxalic acid as a capping agent. The calculated average size of the synthesized ZnO with different capping agents was found to be 32.1 nm. Electronic properties of cyanidin and delphinidin dye were studied using density functional theory (DFT) and time-dependent DFT with a B3LYP/6-31G(d,p) level. By comparing the theoretical results with the experimental data, the cyanidin dye can be used as a sensitizer in dye-sensitized solar cells. An efficiency of 0.006% under an AM-1.5 illumination at 100  mW/cm(2) was attained. The influence of dye adsorption time on the solar cell performance is discussed.

Proton deflectometry of laser-driven relativistic electron jet from thin foil target

NASA Astrophysics Data System (ADS)

Huang, Chengkun; Palaniyappan, S.; Gautier, D. C.; Johnson, R. P.; Shimada, T.; Fernandez, J. C.; Tsung, F. S.; Mori, W. B.

2017-10-01

Near critical density relativistic electron jets from laser solid interaction carry currents approaching the Alfvén-limit and tens of kilo-Tesla magnetic fields. Such jets are often found in kinetic simulations with low areal density targets, but have not been confirmed experimentally. They may be used for X/gamma-ray generation and is also important for the understanding of post-transparency plasma dynamics. With a short-pulse probe beam at the Trident laser facility, we employed proton deflectometry to infer the jet's properties, structure and the long-time dynamics. We develop corresponding GEANT4 simulation model of the proton deflectometry, with input from the kinetic PIC simulations in 2D and quasi-3D geometry, to compare with the experimental radiography images. Detail comparison of the experimental and simulation features in the deflectometry will be discussed. Work supported by the LDRD program at LANL.

An introduction to photocatalysis through methylene blue photodegradation

NASA Astrophysics Data System (ADS)

Petit, Matthieu; Michez, Lisa; Raimundo, Jean-Manuel; Malinowski, Tuhiti; Dumas, Philippe

2016-11-01

We described a simple experimental set-up for lab work on the photocatalytic degradation of methylene blue by TiO2 nanoparticles. The photocatalysis process can be used for many applications. Treatments for diluted wastewater industries, air purifying in underground car parks, and preventing fouling on glass surfaces, are some of the potential applications of this phenomenon. The described experiment is easy to perform and the interpretation can be easily adapted to different levels of students, from high school students demonstrating their interest in sustainable development, to students obtaining a Masters in science departments who want to propose a full explanation for all phenomena of the photocatalytic process. Starting with a description of the experimental set-up, we analysed the photocatalyst nanoparticles and applied the Langmuir-Hinshelwood model to our experimental data. Finally we briefly discussed the respective energetic levels of the photocatalyst semiconductor and methylene blue.

Exploiting single-cell variability to infer the dynamics of immune responses

NASA Astrophysics Data System (ADS)

Höfer, Thomas

Cell division, differentiation, migration and death determine the dynamics of immune responses. These processes are regulated by a multitude of biochemical signals which, at present, cannot faithfully be reconstituted outside the living organism. However, quantitative measurements in living organisms have been limited. In recent years experimental techniques for the ``fate mapping'' of single immune cells have been developed that allow performing parallel single-cell experiments in an experimental animal. The resulting data are more informative about underlying biological processes than traditional measurements. I will show how the theory of stochastic dynamical systems can be used to infer the topology and dynamics of cell differentiation pathways from such data. The focus will be on joint theoretical and experimental work addressing: (i) the development of immune cells during hematopoiesis, and (ii) T cell responses to diverse pathogens. I will discuss questions on the nature of cellular variability that are posed by these new findings.

Observing Ambipolar Behavior and Bandgap Engineering of MoS2 with Transport Measurements

NASA Astrophysics Data System (ADS)

Morris, Rachael; Wilson, Cedric; Hamblin, Glen; Tsuchikawa, Ryuichi; Deshpande, Vikram V.

Molybdenum disulfide is a transition metal semiconductor with a relatively large bandgap about 1.8 eV. In MoS2\\ it is expected that the bandgap is layer dependent and changes with the application of strain. In this talk I will outline our attempt to make simple field effect transistors with thin MoS2 on flexible substrates. Our aim was to see the bandgap of MoS2 directly via transport measurements using electrolytic gating, then apply uniaxial strain to a single layer MoS2 device to see the bandgap change. This was to be one way of confirming theoretical expectations, as well as compare with experimental results already obtained through photoluminescence spectroscopy. Though we did not obtain our target result with this stage of the experiment, future experimental work is planned. I will discuss the experimental method, the challenges of obtaining data and the results we obtained.

PsyGlass: Capitalizing on Google Glass for naturalistic data collection.

PubMed

Paxton, Alexandra; Rodriguez, Kevin; Dale, Rick

2015-09-01

As commercial technology moves further into wearable technologies, cognitive and psychological scientists can capitalize on these devices to facilitate naturalistic research designs while still maintaining strong experimental control. One such wearable technology is Google Glass (Google, Inc.: www.google.com/glass), which can present wearers with audio and visual stimuli while tracking a host of multimodal data. In this article, we introduce PsyGlass, a framework for incorporating Google Glass into experimental work that is freely available for download and community improvement over time (www.github.com/a-paxton/PsyGlass). As a proof of concept, we use this framework to investigate dual-task pressures on naturalistic interaction. The preliminary study demonstrates how designs from classic experimental psychology may be integrated in naturalistic interactive designs with emerging technologies. We close with a series of recommendations for using PsyGlass and a discussion of how wearable technology more broadly may contribute to new or adapted naturalistic research designs.

In-flight measured and predicted ambient dose equivalent and latitude differences on effective dose estimates.

PubMed

Saez Vergara, J C; Romero Gutiérrez, A M; Rodriguez Jiménez, R; Dominguez-Mompell Román, R

2004-01-01

The results from 2 years (2001-2002) of experimental measurements of in-board radiation doses received at IBERIA commercial flights are presented. The routes studied cover the most significant destinations and provide a good estimate of the route doses as required by the new Spanish regulations on air crew radiation protection. Details on the experimental procedures and calibration methods are given. The experimental measurements from the different instruments (Tissue Equivalent Proportional Counter and the combination of a high pressure ion chamber and a high-energy neutron compensated rem-counter) and their comparison with the predictions from some route-dose codes (CARI-6, EPCARD 3.2) are discussed. In contrast with the already published data, which are mainly focused on North latitudes over parallel 50, many of the data presented in this work have been obtained for routes from Spain to Central and South America.

Electrical-thermal-structural finite element simulation and experimental study of a plasma ion source for the production of radioactive ion beams

NASA Astrophysics Data System (ADS)

Manzolaro, M.; Meneghetti, G.; Andrighetto, A.; Vivian, G.

2016-03-01

The production target and the ion source constitute the core of the selective production of exotic species (SPES) facility. In this complex experimental apparatus for the production of radioactive ion beams, a 40 MeV, 200 μA proton beam directly impinges a uranium carbide target, generating approximately 1013 fissions per second. The transfer line enables the unstable isotopes generated by the 238U fissions in the target to reach the ion source, where they can be ionized and finally accelerated to the subsequent areas of the facility. In this work, the plasma ion source currently adopted for the SPES facility is analyzed in detail by means of electrical, thermal, and structural numerical models. Next, theoretical results are compared with the electric potential difference, temperature, and displacement measurements. Experimental tests with stable ion beams are also presented and discussed.

Working Together: Contributions of Corpus Analyses and Experimental Psycholinguistics to Understanding Conversation

PubMed Central

Meyer, Antje S.; Alday, Phillip M.; Decuyper, Caitlin; Knudsen, Birgit

2018-01-01

As conversation is the most important way of using language, linguists and psychologists should combine forces to investigate how interlocutors deal with the cognitive demands arising during conversation. Linguistic analyses of corpora of conversation are needed to understand the structure of conversations, and experimental work is indispensable for understanding the underlying cognitive processes. We argue that joint consideration of corpus and experimental data is most informative when the utterances elicited in a lab experiment match those extracted from a corpus in relevant ways. This requirement to compare like with like seems obvious but is not trivial to achieve. To illustrate this approach, we report two experiments where responses to polar (yes/no) questions were elicited in the lab and the response latencies were compared to gaps between polar questions and answers in a corpus of conversational speech. We found, as expected, that responses were given faster when they were easy to plan and planning could be initiated earlier than when they were harder to plan and planning was initiated later. Overall, in all but one condition, the latencies were longer than one would expect based on the analyses of corpus data. We discuss the implication of this partial match between the data sets and more generally how corpus and experimental data can best be combined in studies of conversation. PMID:29706919

Using the Git Software Tool on the Peregrine System | High-Performance

Science.gov Websites

branch workflow. Create a local branch called "experimental" based on the current master... git branch experimental Use your branch (start working on that experimental branch....) git checkout experimental git pull origin experimental # work, work, work, commit.... Send local branch to the repo git push

Weak Localization and Antilocalization in Topological Materials with Impurity Spin-Orbit Interactions

PubMed Central

Hankiewicz, Ewelina M.; Culcer, Dimitrie

2017-01-01

Topological materials have attracted considerable experimental and theoretical attention. They exhibit strong spin-orbit coupling both in the band structure (intrinsic) and in the impurity potentials (extrinsic), although the latter is often neglected. In this work, we discuss weak localization and antilocalization of massless Dirac fermions in topological insulators and massive Dirac fermions in Weyl semimetal thin films, taking into account both intrinsic and extrinsic spin-orbit interactions. The physics is governed by the complex interplay of the chiral spin texture, quasiparticle mass, and scalar and spin-orbit scattering. We demonstrate that terms linear in the extrinsic spin-orbit scattering are generally present in the Bloch and momentum relaxation times in all topological materials, and the correction to the diffusion constant is linear in the strength of the extrinsic spin-orbit. In topological insulators, which have zero quasiparticle mass, the terms linear in the impurity spin-orbit coupling lead to an observable density dependence in the weak antilocalization correction. They produce substantial qualitative modifications to the magnetoconductivity, differing greatly from the conventional Hikami-Larkin-Nagaoka formula traditionally used in experimental fits, which predicts a crossover from weak localization to antilocalization as a function of the extrinsic spin-orbit strength. In contrast, our analysis reveals that topological insulators always exhibit weak antilocalization. In Weyl semimetal thin films having intermediate to large values of the quasiparticle mass, we show that extrinsic spin-orbit scattering strongly affects the boundary of the weak localization to antilocalization transition. We produce a complete phase diagram for this transition as a function of the mass and spin-orbit scattering strength. Throughout the paper, we discuss implications for experimental work, and, at the end, we provide a brief comparison with transition metal dichalcogenides. PMID:28773167

Summary of the 6th asia-pacific transport working group (APTWG) meeting

NASA Astrophysics Data System (ADS)

Jhang, Hogun; Ghim, Y.-c.; Wang, Zheng-Xiong; Kwon, J. M.; Tamura, N.

2017-08-01

This report summarizes the contributions to, and discussions at, the 6th Asia-Pacific Transport Working Group (APTWG) meeting, held on 21-25 June 2016 at Korea University, Seoul, Republic of Korea. The objective of the meeting was to develop an integrated understanding of transport phenomena in magnetically confined plasmas. To accomplish this objective, four technical working groups were organized under the headings: (1) turbulence suppression and transport bifurcation, (2) effect of magnetic topology on transport and magnetohydrodynamics-turbulence interaction, (3) nonlocality and non-diffusive transport, and (4) Energetic particles and particle/impurity transport. A summary is also given of the three plenary review talks on impurity transport, the magnetohydrodynamics relaxation process in reversed field pinch, and recent experimental and modelling results on the quiescent H-mode operation.

Fuel-Air Mixing and Combustion in Scramjets

NASA Technical Reports Server (NTRS)

Drummond, J. P.; Diskin, Glenn S.; Cutler, A. D.

2002-01-01

Activities in the area of scramjet fuel-air mixing and combustion associated with the Research and Technology Organization Working Group on Technologies for Propelled Hypersonic Flight are described. Work discussed in this paper has centered on the design of two basic experiments for studying the mixing and combustion of fuel and air in a scramjet. Simulations were conducted to aid in the design of these experiments. The experimental models were then constructed, and data were collected in the laboratory. Comparison of the data from a coaxial jet mixing experiment and a supersonic combustor experiment with a combustor code were then made and described. This work was conducted by NATO to validate combustion codes currently employed in scramjet design and to aid in the development of improved turbulence and combustion models employed by the codes.

GFORCE-PD still going strong in 2016

PubMed Central

Parmar, Malin; Takahashi, Jun; Studer, Lorenz; Barker, Roger A

2017-01-01

In 2014, a new initiative was undertaken by groups working on plans for the transplantation of stem-cell-based derived dopaminergic neurons for treating Parkinson’s disease patients. This GForce-PD group held its annual meeting on 18–19 April 2016 in Chicago at Rush University to discuss their progress and the challenges that the translation of this experimental therapy still faces. Over 2 days, the key issues were discussed around the cell lines that will be used, the differentiation protocols, preclinical testing, GMP-adaptation, and cell manufacturing to allow first in human clinical trials, which are anticipated to start in 2017–2018. GForce-PD members also discussed how they can improve outreach and be of better service to the Parkinson's disease (PD) community and help them to make the best possible decisions when pursuing stem cell treatments.

Relativity in the Global Positioning System.

PubMed

Ashby, Neil

2003-01-01

The Global Positioning System (GPS) uses accurate, stable atomic clocks in satellites and on the ground to provide world-wide position and time determination. These clocks have gravitational and motional frequency shifts which are so large that, without carefully accounting for numerous relativistic effects, the system would not work. This paper discusses the conceptual basis, founded on special and general relativity, for navigation using GPS. Relativistic principles and effects which must be considered include the constancy of the speed of light, the equivalence principle, the Sagnac effect, time dilation, gravitational frequency shifts, and relativity of synchronization. Experimental tests of relativity obtained with a GPS receiver aboard the TOPEX/POSEIDON satellite will be discussed. Recently frequency jumps arising from satellite orbit adjustments have been identified as relativistic effects. These will be explained and some interesting applications of GPS will be discussed.

Stanovich's arguments against the "adaptive rationality" project: An assessment.

PubMed

Polonioli, Andrea

2015-02-01

This paper discusses Stanovich's appeal to individual differences in reasoning and decision-making to undermine the "adaptive rationality" project put forth by Gigerenzer and his co-workers. I discuss two different arguments based on Stanovich's research. First, heterogeneity in the use of heuristics seems to be at odds with the adaptationist background of the project. Second, the existence of correlations between cognitive ability and susceptibility to cognitive bias suggests that the "standard picture of rationality" (Stein, 1996, 4) is normatively adequate. I argue that, as matters stand, none of the arguments can be seen as fully compelling. Nevertheless, my discussion is not only critical of Stanovich's research, as I also show that (and how) his research can push forward the so-called "rationality debate" by encouraging greater theoretical and experimental work. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimizing Experimental Design for Comparing Models of Brain Function

PubMed Central

Daunizeau, Jean; Preuschoff, Kerstin; Friston, Karl; Stephan, Klaas

2011-01-01

This article presents the first attempt to formalize the optimization of experimental design with the aim of comparing models of brain function based on neuroimaging data. We demonstrate our approach in the context of Dynamic Causal Modelling (DCM), which relates experimental manipulations to observed network dynamics (via hidden neuronal states) and provides an inference framework for selecting among candidate models. Here, we show how to optimize the sensitivity of model selection by choosing among experimental designs according to their respective model selection accuracy. Using Bayesian decision theory, we (i) derive the Laplace-Chernoff risk for model selection, (ii) disclose its relationship with classical design optimality criteria and (iii) assess its sensitivity to basic modelling assumptions. We then evaluate the approach when identifying brain networks using DCM. Monte-Carlo simulations and empirical analyses of fMRI data from a simple bimanual motor task in humans serve to demonstrate the relationship between network identification and the optimal experimental design. For example, we show that deciding whether there is a feedback connection requires shorter epoch durations, relative to asking whether there is experimentally induced change in a connection that is known to be present. Finally, we discuss limitations and potential extensions of this work. PMID:22125485

The Role of Photographs and Films in Kettlewell's Popularizations of the Phenomenon of Industrial Melanism

NASA Astrophysics Data System (ADS)

Wÿss Rudge, David

H.B.D. Kettlewell's investigations on the phenomenon of industrial melanism are generally referred to in textbooks and other popularizations of science as the classic demonstration of natural selection (Majerus 1989). A central question for historians of this episode is accounting for why public perceptions of the importance of Kettlewell's work have diverged from those of researchers who actually work on the phenomenon. In a recent paper published in Biology and Philosophy, Joel Hagen draws attention to the role Kettlewell and his colleagues played in idealizing his investigations as an example of controlled experimentation in their several retrospective popular accounts. The present essay discusses the important role photographic and film depictions of differential bird predation played in Kettlewell's popularizations. This analysis supports Hagen's contentions that Kettlewell deftly and strategically used these visual representations to command assent to his interpretation of the phenomenon and shore up claims about the scientific legitimacy and importance of his work. It nevertheless disputes that these images were intended to portray Kettlewell's experiments as an example of controlled experimentation. In a concluding section, the essay draws several morals from this analysis regarding the use of popularized articles and visual images to teach science.

The evolved psychological mechanisms of fertility motivation: hunting for causation in a sea of correlation

PubMed Central

McAllister, Lisa S.; Pepper, Gillian V.; Virgo, Sandra

2016-01-01

Cultural, ecological, familial and physiological factors consistently influence fertility behaviours, however, the proximate psychological mechanisms underlying fertility decisions in humans are poorly understood. Understanding the psychological mechanisms underlying human fertility may illuminate the final processes by which some of these known predictors have their influence. To date, research into the psychological mechanisms underlying fertility has been fragmented. Aspects of reproductive psychology have been examined by researchers in a range of fields, but the findings have not been systematically integrated in one review. We provide such a review, examining current theories and research on psychological mechanisms of fertility. We examine the methods and populations used in the research, as well as the disciplines and theoretical perspectives from which the work has come. Much of the work that has been done to date is methodologically limited to examining correlations between ecological, social and economic factors and fertility. We propose, and support with examples, the use of experimental methods to differentiate causal factors from correlates. We also discuss weaknesses in the experimental research, including limited work with non-WEIRD (western, educated, industrialized, rich and democratic) populations. PMID:27022078

Heat strain models applicable for protective clothing: Comparison of core temperature response. Technical report

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

Gonzalez, R.R.; McLellan, T.M.; Withey, W.R.

This report represents the results of TTCP-UTP6 efforts on modeling aspects when chemical protective ensembles are worn which need to be considered in warm environments. Since 1983, a significant data base has been collected using human experimental studies and wide clothing systems from which predictive modeling equations have been developed with individuals working in temperate and hot environments, but few comparisons of the -- results from various model outputs have ever been carried out. This initial comparison study was part of a key technical area (KIA) project for The Technical Cooperation Program (TTCP) UTP-6 working party. A modeling workshop wasmore » conducted in Toronto, Canada on 9-10 June 1994 to discuss the data reduction and results acquired in an initial clothing analysis study of TTCP using various chemical protective garments. To our knowledge, no comprehensive study to date has ever focused on comparing experimental results using an international standardized heat stress procedure matched to physiological outputs from various model predictions in individuals dressed in chemical protective clothing systems. This is the major focus of this TTCP key technical study. This technical report covers one aspect of the working party`s results.« less

Numerical investigation of exact coherent structures in turbulent small-aspect-ratio Taylor-Couette flow

NASA Astrophysics Data System (ADS)

Krygier, Michael; Crowley, Christopher J.; Schatz, Michael F.; Grigoriev, Roman O.

2017-11-01

As suggested by recent theoretical and experimental studies, fluid turbulence can be described as a walk between neighborhoods of unstable nonchaotic solutions of the Navier-Stokes equation known as exact coherent structures (ECS). Finding ECS in an experimentally-accessible setting is the first step toward rigorous testing of the dynamical role of ECS in 3D turbulence. We found several ECS (both relative periodic orbits and relative equilibria) in a weakly turbulent regime of small-aspect-ratio Taylor-Couette flow with counter-rotating cylinders. This talk will discuss how the geometry of these solutions guides the evolution of turbulent flow in the simulations. This work is supported by the Army Research Office (Contract # W911NF-15-1-0471).

Effects of a spin-flavour-dependent interaction on light-flavoured baryon helicity amplitudes

NASA Astrophysics Data System (ADS)

Ronniger, Michael; Metsch, Bernard Ch.

2013-01-01

This paper is a continuation of a previous work about the effects of a phenomenological flavour-dependent force in a relativistically covariant constituent quark model based on the Salpeter equation on the structure of light-flavoured baryon resonances. Here the longitudinal and transverse helicity amplitudes as studied experimentally in the electro-excitation of nucleon- and Δ-resonances are calculated. In particular the amplitudes for the excitation of three- and four-star resonances as calculated in a previous model A are compared to those of the novel model C as well as to existing and partially new experimental data such as, e.g., determined by the CB-ELSA Collaboration. A brief discussion on some improvements to model C is given after the introduction.

Superposing pure quantum states with partial prior information

NASA Astrophysics Data System (ADS)

Dogra, Shruti; Thomas, George; Ghosh, Sibasish; Suter, Dieter

2018-05-01

The principle of superposition is an intriguing feature of quantum mechanics, which is regularly exploited in many different circumstances. A recent work [M. Oszmaniec et al., Phys. Rev. Lett. 116, 110403 (2016), 10.1103/PhysRevLett.116.110403] shows that the fundamentals of quantum mechanics restrict the process of superimposing two unknown pure states, even though it is possible to superimpose two quantum states with partial prior knowledge. The prior knowledge imposes geometrical constraints on the choice of input states. We discuss an experimentally feasible protocol to superimpose multiple pure states of a d -dimensional quantum system and carry out an explicit experimental realization for two single-qubit pure states with partial prior information on a two-qubit NMR quantum information processor.

Physical and mathematical modelling of ladle metallurgy operations. [steelmaking

NASA Technical Reports Server (NTRS)

El-Kaddah, N.; Szekely, J.

1982-01-01

Experimental measurements are reported, on the velocity fields and turbulence parameters on a water model of an argon stirred ladle. These velocity measurements are complemented by direct heat transfer measurements, obtained by studying the rate at which ice rods immersed into the system melt, at various locations. The theoretical work undertaken involved the use of the turbulence Navier-Stokes equations in conjunction with the kappa-epsilon model to predict the local velocity fields and the maps of the turbulence parameters. Theoretical predictions were in reasonably good agreement with the experimentally measured velocity fields; the agreement between the predicted and the measured turbulence parameters was less perfect, but still satisfactory. The implications of these findings to the modelling of ladle metallurgical operations are discussed.

PERF - A new approach to the experimental study of radiative aerodynamic heating and radiative blockage by ablation products

NASA Technical Reports Server (NTRS)

Walberg, G.

1974-01-01

The present work describes a facility designed to validate the various aspects of radiative flow field theory, including the absorption of shock layer radiation by ablation products. The facility is capable of producing radiation with a spectrum similar to that of an entry vehicle shock layer and is designed to allow measurements at vacuum ultraviolet wavelengths where the most significant absorption by ablation products is predicted to occur. The design concept of the facility is presented along with results of theoretical analyses carried out to assess its research potential. Experimental data obtained during tests that simulated earth and Venusian entry and in which simulated ablation products were injected into the stagnation region flow field are discussed.

Nanopores formed by DNA origami: a review.

PubMed

Bell, Nicholas A W; Keyser, Ulrich F

2014-10-01

Nanopores have emerged over the past two decades to become an important technique in single molecule experimental physics and biomolecule sensing. Recently DNA nanotechnology, in particular DNA origami, has been used for the formation of nanopores in insulating materials. DNA origami is a very attractive technique for the formation of nanopores since it enables the construction of 3D shapes with precise control over geometry and surface functionality. DNA origami has been applied to nanopore research by forming hybrid architectures with solid state nanopores and by direct insertion into lipid bilayers. This review discusses recent experimental work in this area and provides an outlook for future avenues and challenges. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

An Overview of an Experimental Demonstration Aerotow Program

NASA Technical Reports Server (NTRS)

Murray, James E.; Bowers, Albion H.; Lokos, William A.; Peters, Todd L.; Gera, Joseph

1998-01-01

An overview of an experimental demonstration of aerotowing a delta-wing airplane with low-aspect ratio and relatively high wing loading is presented. Aerotowing of future space launch configurations is a new concept, and the objective of the work described herein is to demonstrate the aerotow operation using an airplane configuration similar to conceptual space launch vehicles. Background information on the use of aerotow for a space launch vehicle is presented, and the aerotow system used in this demonstration is described. The ground tests, analytical studies, and flight planning used to predict system behavior and to enhance flight safety are detailed. The instrumentation suite and flight test maneuvers flown are discussed, preliminary performance is assessed, and flight test results are compared with the preflight predictions.

Dynamics of microtubules: highlights of recent computational and experimental investigations

NASA Astrophysics Data System (ADS)

Barsegov, Valeri; Ross, Jennifer L.; Dima, Ruxandra I.

2017-11-01

Microtubules are found in most eukaryotic cells, with homologs in eubacteria and archea, and they have functional roles in mitosis, cell motility, intracellular transport, and the maintenance of cell shape. Numerous efforts have been expended over the last two decades to characterize the interactions between microtubules and the wide variety of microtubule associated proteins that control their dynamic behavior in cells resulting in microtubules being assembled and disassembled where and when they are required by the cell. We present the main findings regarding microtubule polymerization and depolymerization and review recent work about the molecular motors that modulate microtubule dynamics by inducing either microtubule depolymerization or severing. We also discuss the main experimental and computational approaches used to quantify the thermodynamics and mechanics of microtubule filaments.

Laser-ion accelerators: State-of-the-art and scaling laws

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

Borghesi, M.; Kar, S.; Margarone, D.

2013-07-26

A significant amount of experimental work has been devoted over the last decade to the development and optimization of proton acceleration based on the so-called Target Normal Sheath acceleration mechanism. Several studies have been dedicated to the determination of scaling laws for the maximum energy of the protons as a function of the parameters of the irradiating pulses, studies based on experimental results and on models of the acceleration process. We briefly summarize the state of the art in this area, and review some of the scaling studies presented in the literature. We also discuss some recent results, and projectedmore » scalings, related to a different acceleration mechanism for ions, based on the Radiation Pressure of an ultraintense laser pulse.« less

State variable theories based on Hart's formulation

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

Korhonen, M.A.; Hannula, S.P.; Li, C.Y.

In this paper a review of the development of a state variable theory for nonelastic deformation is given. The physical and phenomenological basis of the theory and the constitutive equations describing macroplastic, microplastic, anelastic and grain boundary sliding enhanced deformation are presented. The experimental and analytical evaluation of different parameters in the constitutive equations are described in detail followed by a review of the extensive experimental work on different materials. The technological aspects of the state variable approach are highlighted by examples of the simulative and predictive capabilities of the theory. Finally, a discussion of general capabilities, limitations and futuremore » developments of the theory and particularly the possible extensions to cover an even wider range of deformation or deformation-related phenomena is presented.« less

Resonant electron tunneling spectroscopy of antibonding states in a Dirac semimetal

NASA Astrophysics Data System (ADS)

Marques, Y.; Yudin, D.; Shelykh, I. A.; Seridonio, A. C.

2018-06-01

Recently, it was shown both theoretically and experimentally that certain three-dimensional (3D) materials have Dirac points in the Brillouin zone, thus being 3D analogs of graphene. Moreover, it was suggested that under specific conditions a pair of localized impurities placed inside a three-dimensional Dirac semimetal may lead to the formation of an unusual antibonding state. In the meantime, the effect of vibrational degrees of freedom which are present in any realistic system has avoided attention. In this work, we address the influence of phonons on characteristic features of (anti)bonding state, and discuss how these results can be tested experimentally via local probing, namely, inelastic electron tunneling spectroscopy curve obtained in STM measurements.

Crystal plasticity modeling of irradiation growth in Zircaloy-2

DOE PAGES

Patra, Anirban; Tome, Carlos; Golubov, Stanislav I.

2017-05-10

A reaction-diffusion based mean field rate theory model is implemented in the viscoplastic self-consistent (VPSC) crystal plasticity framework to simulate irradiation growth in hcp Zr and its alloys. A novel scheme is proposed to model the evolution (both number density and radius) of irradiation-induced dislocation loops that can be informed directly from experimental data of dislocation density evolution during irradiation. This framework is used to predict the irradiation growth behavior of cold-worked Zircaloy-2 and trends compared to available experimental data. The role of internal stresses in inducing irradiation creep is discussed. Effects of grain size, texture, and external stress onmore » the coupled irradiation growth and creep behavior are also studied.« less

Crystal plasticity modeling of irradiation growth in Zircaloy-2

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

Patra, Anirban; Tome, Carlos; Golubov, Stanislav I.

A reaction-diffusion based mean field rate theory model is implemented in the viscoplastic self-consistent (VPSC) crystal plasticity framework to simulate irradiation growth in hcp Zr and its alloys. A novel scheme is proposed to model the evolution (both number density and radius) of irradiation-induced dislocation loops that can be informed directly from experimental data of dislocation density evolution during irradiation. This framework is used to predict the irradiation growth behavior of cold-worked Zircaloy-2 and trends compared to available experimental data. The role of internal stresses in inducing irradiation creep is discussed. Effects of grain size, texture, and external stress onmore » the coupled irradiation growth and creep behavior are also studied.« less

Non-Newtonian fluids: Frictional pressure loss prediction for fully-developed flow in straight pipes

NASA Astrophysics Data System (ADS)

1991-10-01

ESDU 91025 discusses models used to describe the rheology of time independent pseudohomogeneous non-Newtonian fluids (power-law, Bingham, Herschel-Bulkley and a generalized model due to Metzner and Reed); they are used to calculate the laminar flow pressure drop (which is independent of pipe roughness in this regime). Values of a generalized Reynolds number are suggested to define transitional and turbulent flow. For turbulent flow in smooth pipes, pressure loss is estimated on the basis of an experimentally determined rheogram using either the Dodge-Metzner or Bowen approach depending on the available measurements. Bowen requires results for at least two pipe diameters. The choice of Dodge-Metzner when data are limited is discussed; seven possible methods are assessed against five sets of experimental results drawn from the literature. No method is given for transitional flow, which it is suggested should be avoided, but the turbulent correlation is recommended because it will yield an overestimate. Suggestions are made for the treatment of roughness effects. Several worked examples illustrate the use of the methods and a flowchart guides the user through the process from experimentally characterizing the behavior of the fluid to determining the pressure drop. A computer program, ESDUpac A9125, is also provided.

Ignition of Cellulosic Paper at Low Radiant Fluxes

NASA Technical Reports Server (NTRS)

White, K. Alan

1996-01-01

The ignition of cellulosic paper by low level thermal radiation is investigated. Past work on radiative ignition of paper is briefly reviewed. No experimental study has been reported for radiative ignition of paper at irradiances below 10 Watts/sq.cm. An experimental study of radiative ignition of paper at these low irradiances is reported. Experimental parameters investigated and discussed include radiant power levels incident on the sample, the method of applying the radiation (focussed vs. diffuse Gaussian source), the presence and relative position of a separate pilot ignition source, and the effects of natural convection (buoyancy) on the ignition process in a normal gravity environment. It is observed that the incident radiative flux (in W/sq.cm) has the greatest influence on ignition time. For a given flux level, a focussed Gaussian source is found to be advantageous to a more diffuse, lower amplitude, thermal source. The precise positioning of a pilot igniter relative to gravity and to the fuel sample affects the ignition process, but the precise effects are not fully understood. Ignition was more readily achieved and sustained with a horizontal fuel sample, indicating the buoyancy plays a role in the ignition process of cellulosic paper. Smoldering combustion of doped paper samples was briefly investigated, and results are discussed.

[Historical materials of Chinese food hygiene (1927-1949)].

PubMed

Li, X; Wang, X

1997-01-01

The author discusses the situation on the work of food hygiene from 1928 to 1949 in China. During this period, the Health and Epidemic Prevention Bureau under the Ministry of Health were all in charge of food hygiene work. They formulated a series of standards, laws and rules on food hygiene which were carried out by hygienic policemen of the Bureau of Public Security. There were two ways for the education of food hygiene: Short-term course teaching class for food hygiene in medical college. The inspection and research work of food hygiene were performed by the Central Testing House of Hygiene, The Central Experimental Office of Hygienic Facilities and the Central Office of Epidemic Prevention and Nutritional Institute of the Health Office. After anti-Japanese war was broken out in 1937, food hygiene work were carried out mainly in the service in the war.

Nuclear fission: a review of experimental advances and phenomenology

NASA Astrophysics Data System (ADS)

Andreyev, A. N.; Nishio, K.; Schmidt, K.-H.

2018-01-01

In the last two decades, through technological, experimental and theoretical advances, the situation in experimental fission studies has changed dramatically. With the use of advanced production and detection techniques both much more detailed and precise information can now be obtained for the traditional regions of fission research and, crucially, new regions of nuclei have become routinely accessible for fission studies. This work first of all reviews the recent developments in experimental fission techniques, in particular the resurgence of transfer-induced fission reactions with light and heavy ions, the emerging use of inverse-kinematic approaches, both at Coulomb and relativistic energies, and of fission studies with radioactive beams. The emphasis on the fission-fragment mass and charge distributions will be made in this work, though some of the other fission observables, such as prompt neutron and γ-ray emission will also be reviewed. A particular attention will be given to the low-energy fission in the so far scarcely explored nuclei in the very neutron-deficient lead region. They recently became the focus for several complementary experimental studies, such as β-delayed fission with radioactive beams at ISOLDE(CERN), Coulex-induced fission of relativistic secondary beams at FRS(GSI), and several prompt fusion–fission studies. The synergy of these approaches allows a unique insight in the new region of asymmetric fission around {\\hspace{0pt}}180 Hg, recently discovered at ISOLDE. Recent extensive theoretical efforts in this region will also be outlined. The unprecedented high-quality data for fission fragments, completely identified in Z and A, by means of reactions in inverse kinematics at FRS(GSI) and VAMOS(GANIL) will be also reviewed. These experiments explored an extended range of mercury-to-californium elements, spanning from the neutron-deficient to neutron-rich nuclides, and covering both asymmetric, symmetric and transitional fission regions. Some aspects of heavy-ion induced fusion–fission and quasifission reactions will be also discussed, which reveal their dynamical features, such as the fission time scale. The crucial role of the multi-chance fission, probed by means of multinucleon-transfer induced fission reactions, will be highlighted. The review will conclude with the discussion of the new experimental fission facilities which are presently being brought into operation, along with promising ‘next-generation’ fission approaches, which might become available within the next decade.

String theory--the physics of string-bending and other electric guitar techniques.

PubMed

Grimes, David Robert

2014-01-01

Electric guitar playing is ubiquitous in practically all modern music genres. In the hands of an experienced player, electric guitars can sound as expressive and distinct as a human voice. Unlike other more quantised instruments where pitch is a discrete function, guitarists can incorporate micro-tonality and, as a result, vibrato and sting-bending are idiosyncratic hallmarks of a player. Similarly, a wide variety of techniques unique to the electric guitar have emerged. While the mechano-acoustics of stringed instruments and vibrating strings are well studied, there has been comparatively little work dedicated to the underlying physics of unique electric guitar techniques and strings, nor the mechanical factors influencing vibrato, string-bending, fretting force and whammy-bar dynamics. In this work, models for these processes are derived and the implications for guitar and string design discussed. The string-bending model is experimentally validated using a variety of strings and vibrato dynamics are simulated. The implications of these findings on the configuration and design of guitars is also discussed.

Influence of boundary conditions on the existence and stability of minimal surfaces of revolution made of soap films

NASA Astrophysics Data System (ADS)

Salkin, Louis; Schmit, Alexandre; Panizza, Pascal; Courbin, Laurent

2014-09-01

Because of surface tension, soap films seek the shape that minimizes their surface energy and thus their surface area. This mathematical postulate allows one to predict the existence and stability of simple minimal surfaces. After briefly recalling classical results obtained in the case of symmetric catenoids that span two circular rings with the same radius, we discuss the role of boundary conditions on such shapes, working with two rings having different radii. We then investigate the conditions of existence and stability of other shapes that include two portions of catenoids connected by a planar soap film and half-symmetric catenoids for which we introduce a method of observation. We report a variety of experimental results including metastability—an hysteretic evolution of the shape taken by a soap film—explained using simple physical arguments. Working by analogy with the theory of phase transitions, we conclude by discussing universal behaviors of the studied minimal surfaces in the vicinity of their existence thresholds.

A Module Experimental Process System Development Unit (MEPSDU)

NASA Technical Reports Server (NTRS)

1981-01-01

Design work for a photovoltaic module, fabricated using single crystal silicon dendritic web sheet material, resulted in the identification of surface treatment to the module glass superstrate which improved module efficiencies. A final solar module environmental test, a simulated hailstone impact test, was conducted on full size module superstrates to verify that the module's tempered glass superstrate can withstand specified hailstone impacts near the corners and edges of the module. Process sequence design work on the metallization process selective, liquid dopant investigation, dry processing, and antireflective/photoresist application technique tasks, and optimum thickness for Ti/Pd are discussed. A noncontact cleaning method for raw web cleaning was identified and antireflective and photoresist coatings for the dendritic webs were selected. The design of a cell string conveyor, an interconnect feed system, rolling ultrasonic spot bonding heat, and the identification of the optimal commercially available programmable control system are also discussed. An economic analysis to assess cost goals of the process sequence is also given.

String Theory - The Physics of String-Bending and Other Electric Guitar Techniques

PubMed Central

Grimes, David Robert

2014-01-01

Electric guitar playing is ubiquitous in practically all modern music genres. In the hands of an experienced player, electric guitars can sound as expressive and distinct as a human voice. Unlike other more quantised instruments where pitch is a discrete function, guitarists can incorporate micro-tonality and, as a result, vibrato and sting-bending are idiosyncratic hallmarks of a player. Similarly, a wide variety of techniques unique to the electric guitar have emerged. While the mechano-acoustics of stringed instruments and vibrating strings are well studied, there has been comparatively little work dedicated to the underlying physics of unique electric guitar techniques and strings, nor the mechanical factors influencing vibrato, string-bending, fretting force and whammy-bar dynamics. In this work, models for these processes are derived and the implications for guitar and string design discussed. The string-bending model is experimentally validated using a variety of strings and vibrato dynamics are simulated. The implications of these findings on the configuration and design of guitars is also discussed. PMID:25054880

Explosively produced fracture of oil shale

NASA Astrophysics Data System (ADS)

Morris, W. A.

1982-05-01

Rock fragmentation research in oil shale to develop the blasting technologies and designs required to prepare a rubble bed for a modified in situ retort is reported. Experimental work is outlined, proposed studies in explosive characterization are detailed and progress in numerical calculation techniques to predict fracture of the shale is described. A detailed geologic characterization of two Anvil Points experiment sites is related to previous work at Colony Mine. The second section focuses on computer modeling and theory. The latest generation of the stress wave code SHALE, its three dimensional potential, and the slide line package for it are described. A general stress rate equation that takes energy dependence into account is discussed.

Sounding ruins: reflections on the production of an 'audio drift'.

PubMed

Gallagher, Michael

2015-07-01

This article is about the use of audio media in researching places, which I term 'audio geography'. The article narrates some episodes from the production of an 'audio drift', an experimental environmental sound work designed to be listened to on a portable MP3 player whilst walking in a ruinous landscape. Reflecting on how this work functions, I argue that, as well as representing places, audio geography can shape listeners' attention and bodily movements, thereby reworking places, albeit temporarily. I suggest that audio geography is particularly apt for amplifying the haunted and uncanny qualities of places. I discuss some of the issues raised for research ethics, epistemology and spectral geographies.

Sounding ruins: reflections on the production of an ‘audio drift’

PubMed Central

Gallagher, Michael

2014-01-01

This article is about the use of audio media in researching places, which I term ‘audio geography’. The article narrates some episodes from the production of an ‘audio drift’, an experimental environmental sound work designed to be listened to on a portable MP3 player whilst walking in a ruinous landscape. Reflecting on how this work functions, I argue that, as well as representing places, audio geography can shape listeners’ attention and bodily movements, thereby reworking places, albeit temporarily. I suggest that audio geography is particularly apt for amplifying the haunted and uncanny qualities of places. I discuss some of the issues raised for research ethics, epistemology and spectral geographies. PMID:29708107

Analysis on ultrashort-pulse laser ablation for nanoscale film of ceramics

NASA Astrophysics Data System (ADS)

Ho, C. Y.; Tsai, Y. H.; Chiou, Y. J.

2017-06-01

This paper uses the dual-phase-lag model to study the ablation characteristics of femtosecond laser processing for nanometer-sized ceramic films. In ultrafast process and ultrasmall size where the two lags occur, a dual-phase-lag can be applied to analyse the ablation characteristics of femtosecond laser processing for materials. In this work, the ablation rates of nanometer-sized lead zirconate titanate (PZT) ceramics are investigated using a dual-phase-lag and the model is solved by Laplace transform method. The results obtained from this work are validated by the available experimental data. The effects of material thermal properties on the ablation characteristics of femtosecond laser processing for ceramics are also discussed.

NOSTOS: a paper-based ubiquitous computing healthcare environment to support data capture and collaboration.

PubMed

Bång, Magnus; Larsson, Anders; Eriksson, Henrik

2003-01-01

In this paper, we present a new approach to clinical workplace computerization that departs from the window-based user interface paradigm. NOSTOS is an experimental computer-augmented work environment designed to support data capture and teamwork in an emergency room. NOSTOS combines multiple technologies, such as digital pens, walk-up displays, headsets, a smart desk, and sensors to enhance an existing paper-based practice with computer power. The physical interfaces allow clinicians to retain mobile paper-based collaborative routines and still benefit from computer technology. The requirements for the system were elicited from situated workplace studies. We discuss the advantages and disadvantages of augmenting a paper-based clinical work environment.

NOSTOS: A Paper–Based Ubiquitous Computing Healthcare Environment to Support Data Capture and Collaboration

PubMed Central

Bång, Magnus; Larsson, Anders; Eriksson, Henrik

2003-01-01

In this paper, we present a new approach to clinical workplace computerization that departs from the window–based user interface paradigm. NOSTOS is an experimental computer–augmented work environment designed to support data capture and teamwork in an emergency room. NOSTOS combines multiple technologies, such as digital pens, walk–up displays, headsets, a smart desk, and sensors to enhance an existing paper–based practice with computer power. The physical interfaces allow clinicians to retain mobile paper–based collaborative routines and still benefit from computer technology. The requirements for the system were elicited from situated workplace studies. We discuss the advantages and disadvantages of augmenting a paper–based clinical work environment. PMID:14728131

Sex differences in visual-spatial working memory: A meta-analysis.

PubMed

Voyer, Daniel; Voyer, Susan D; Saint-Aubin, Jean

2017-04-01

Visual-spatial working memory measures are widely used in clinical and experimental settings. Furthermore, it has been argued that the male advantage in spatial abilities can be explained by a sex difference in visual-spatial working memory. Therefore, sex differences in visual-spatial working memory have important implication for research, theory, and practice, but they have yet to be quantified. The present meta-analysis quantified the magnitude of sex differences in visual-spatial working memory and examined variables that might moderate them. The analysis used a set of 180 effect sizes from healthy males and females drawn from 98 samples ranging in mean age from 3 to 86 years. Multilevel meta-analysis was used on the overall data set to account for non-independent effect sizes. The data also were analyzed in separate task subgroups by means of multilevel and mixed-effects models. Results showed a small but significant male advantage (mean d = 0.155, 95 % confidence interval = 0.087-0.223). All the tasks produced a male advantage, except for memory for location, where a female advantage emerged. Age of the participants was a significant moderator, indicating that sex differences in visual-spatial working memory appeared first in the 13-17 years age group. Removing memory for location tasks from the sample affected the pattern of significant moderators. The present results indicate a male advantage in visual-spatial working memory, although age and specific task modulate the magnitude and direction of the effects. Implications for clinical applications, cognitive model building, and experimental research are discussed.

Stretching the Traditional Notion of Experiment in Computing: Explorative Experiments.

PubMed

Schiaffonati, Viola

2016-06-01

Experimentation represents today a 'hot' topic in computing. If experiments made with the support of computers, such as computer simulations, have received increasing attention from philosophers of science and technology, questions such as "what does it mean to do experiments in computer science and engineering and what are their benefits?" emerged only recently as central in the debate over the disciplinary status of the discipline. In this work we aim at showing, also by means of paradigmatic examples, how the traditional notion of controlled experiment should be revised to take into account a part of the experimental practice in computing along the lines of experimentation as exploration. Taking inspiration from the discussion on exploratory experimentation in the philosophy of science-experimentation that is not theory-driven-we advance the idea of explorative experiments that, although not new, can contribute to enlarge the debate about the nature and role of experimental methods in computing. In order to further refine this concept we recast explorative experiments as socio-technical experiments, that test new technologies in their socio-technical contexts. We suggest that, when experiments are explorative, control should be intended in a posteriori form, in opposition to the a priori form that usually takes place in traditional experimental contexts.

Modeling of Transient Flow Mixing of Streams Injected into a Mixing Chamber

NASA Technical Reports Server (NTRS)

Voytovych, Dmytro M.; Merkle, Charles L.; Lucht, Robert P.; Hulka, James R.; Jones, Gregg W.

2006-01-01

Ignition is recognized as one the critical drivers in the reliability of multiple-start rocket engines. Residual combustion products from previous engine operation can condense on valves and related structures thereby creating difficulties for subsequent starting procedures. Alternative ignition methods that require fewer valves can mitigate the valve reliability problem, but require improved understanding of the spatial and temporal propellant distribution in the pre-ignition chamber. Current design tools based mainly on one-dimensional analysis and empirical models cannot predict local details of the injection and ignition processes. The goal of this work is to evaluate the capability of the modern computational fluid dynamics (CFD) tools in predicting the transient flow mixing in pre-ignition environment by comparing the results with the experimental data. This study is a part of a program to improve analytical methods and methodologies to analyze reliability and durability of combustion devices. In the present paper we describe a series of detailed computational simulations of the unsteady mixing events as the cold propellants are first introduced into the chamber as a first step in providing this necessary environmental description. The present computational modeling represents a complement to parallel experimental simulations' and includes comparisons with experimental results from that effort. A large number of rocket engine ignition studies has been previously reported. Here we limit our discussion to the work discussed in Refs. 2, 3 and 4 which is both similar to and different from the present approach. The similarities arise from the fact that both efforts involve detailed experimental/computational simulations of the ignition problem. The differences arise from the underlying philosophy of the two endeavors. The approach in Refs. 2 to 4 is a classical ignition study in which the focus is on the response of a propellant mixture to an ignition source, with emphasis on the level of energy needed for ignition and the ensuing flame propagation issues. Our focus in the present paper is on identifying the unsteady mixing processes that provide the propellant mixture in which the ignition source is to be placed. In particular, we wish to characterize the spatial and temporal mixture distribution with a view toward identifying preferred spatial and temporal locations for the ignition source. As such, the present work is limited to cold flow (pre-ignition) conditions

Selenium nanomaterials: applications in electronics, catalysis and sensors.

PubMed

Chaudhary, Savita; Mehta, S K

2014-02-01

This review provides insights into the synthesis, functionalization, and applications of selenium nanoparticles in electronics, optics, catalysis and sensors. The variation of physicochemical properties such as particle size, surface area, and shape of the selenium nanoparticles and the effect of experimental conditions has also been discussed. An overview has also been provided on the fundamental electrical and optical properties of selenium nanomaterials as well as their utilization in different research fields. The work presents an insight on selenium nanoparticles with interesting properties and their future applications.

Measurement and Characterization of the Acceleration Environment on Board the Space Station

NASA Technical Reports Server (NTRS)

Baugher, Charles R. (Editor)

1990-01-01

This workshop provides a comprehensive overview of the work and status of each of these areas to provide a basis for establishing a systematic approach to the challenge of avoiding these difficulties during the Space Station era of materials experimentation. The discussions were arranged in the order of: the scientific understanding of the requirements for a micro-gravity environment, a history of acceleration measurements on spacecraft, the state of accelerometer technology, and the current understanding of the predicted Space Station environment.

Radiation hazards to man

NASA Technical Reports Server (NTRS)

Curtis, S. B.; Wilkinson, M. C.

1971-01-01

The secondary dose contribution expected from the heavy primaries of the galactic cosmic rays was evaluated by a calculational technique developed in this study. Improvements in the solar and galactic cosmic ray environments made possible by recent experimental and theoretical work are discussed and presented. The recommendations of the National Academy of Sciences' space radiation study panel, are used in conjunction with a shielding analysis, to evaluate the radiation status of an astronaut during the triple solar particle event of 10, 14, 16 July 1959.

ABC of kink kinetics and density in a complex solution

DOE PAGES

Chernov, A. A.; DeYoreo, J. J.; Rashkovich, L. N.

2007-06-14

This tutorial lecture explains the ways supersaturation in complex solutions may be introduced to be most relevant to describe experimental data on kink and step kinetics. To do so, we express the kink rate via the frequencies of attachment and detachment of the building units and then link these frequencies to the measurable activities of these units in solution. Furthermore, possible reasons for violation of the Gibbs–Thomson law are also briefly discussed with reference to our earlier work.

System Theory and Physiological Processes.

PubMed

Jones, R W

1963-05-03

Engineers and physiologists working together in experimental and theoretical studies predict that the application of system analysis to biological processes will increase understanding of these processes and broaden the base of system theory. Richard W. Jones, professor of electrical engineering at Northwestern University, Evanston, Illinois, and John S. Gray, professor of physiology at Northwestern's Medical School, discuss these developments. Their articles are adapted from addresses delivered in Chicago in November 1962 at the 15th Annual Conference on Engineering in Medicine and Biology.

Comment on "Properties of (26)Mg and (26)Si in the sd shell model and the determination of the (25)Al(p,gamma) (26) Si reaction rate"

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

Chipps, K.; Bardayan, Daniel W; Liang, J Felix

2011-01-01

A recent discussion of theoretical work on the {sup 25}Al(p,{gamma}){sup 26}Si astrophysical reaction rate [W.A. Richter, B. Alex Brown, A. Signoracci and M. Wiescher Phys. Rev. C 83 065803 (2011)] omits some current and relevant experimental information in forming its scientific conclusions. Accounting for this new information has the potential to significantly alter the reaction rate derived in the paper.

Unfolding and unfoldability of digital pulses in the z-domain

NASA Astrophysics Data System (ADS)

Regadío, Alberto; Sánchez-Prieto, Sebastián

2018-04-01

The unfolding (or deconvolution) technique is used in the development of digital pulse processing systems applied to particle detection. This technique is applied to digital signals obtained by digitization of analog signals that represent the combined response of the particle detectors and the associated signal conditioning electronics. This work describes a technique to determine if the signal is unfoldable. For unfoldable signals the characteristics of the unfolding system (unfolder) are presented. Finally, examples of the method applied to real experimental setup are discussed.

Computational modeling of the cell-autonomous mammalian circadian oscillator.

PubMed

Podkolodnaya, Olga A; Tverdokhleb, Natalya N; Podkolodnyy, Nikolay L

2017-02-24

This review summarizes various mathematical models of cell-autonomous mammalian circadian clock. We present the basics necessary for understanding of the cell-autonomous mammalian circadian oscillator, modern experimental data essential for its reconstruction and some special problems related to the validation of mathematical circadian oscillator models. This work compares existing mathematical models of circadian oscillator and the results of the computational studies of the oscillating systems. Finally, we discuss applications of the mathematical models of mammalian circadian oscillator for solving specific problems in circadian rhythm biology.

Mechanotransduction and the Cytoskeleton

NASA Technical Reports Server (NTRS)

Pickard, Barbara G.

1996-01-01

Two intellectual developments in the lab suggested a more powerful approach to the problem defined in the original statement. These were discussed with the "Program Chief', who agreed that an alteration of approach was desirable. Second expansion of our work was on the computational optical sectioning microscope (COSM). Additionally, we hoped to visualize the channels with respect to cytoskeletal entities. We have identified major here-to-fore unknown cytoskeletal structure in our representative experimental system, the onion epidermal cell, and have named this structure the endomembrane grant.

Wave propagation downstream of a high power helicon in a dipolelike magnetic field

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

Prager, James; Winglee, Robert; Roberson, B. Race

2010-01-15

The wave propagating downstream of a high power helicon source in a diverging magnetic field was investigated experimentally. The magnetic field of the wave has been measured both axially and radially. The three-dimensional structure of the propagating wave is observed and its wavelength and phase velocity are determined. The measurements are compared to predictions from helicon theory and that of a freely propagating whistler wave. The implications of this work on the helicon as a thruster are also discussed.

BMC Blood Disorders becomes BMC Hematology: evolving along with the hematology field.

PubMed

Chap, Christna

2013-04-10

This Editorial marks the launch of BMC Hematology, formerly known as BMC Blood Disorders, within the BMC series of journals published by BioMed Central. The scope of BMC Hematology encompasses basic, experimental and clinical research related to hematology. In this Editorial we will discuss the rationale behind this relaunch and how, as an open access journal providing unrestricted and free access to scientific and scholarly work, BMC Hematology will help disseminate research in the hematology field in a freely-accessible manner.

On the relationship between collisionless shock structure and energetic particle acceleration

NASA Technical Reports Server (NTRS)

Kennel, C. F.

1983-01-01

Recent experimental research on bow shock structure and theoretical studies of quasi-parallel shock structure and shock acceleration of energetic particles were reviewed, to point out the relationship between structure and particle acceleration. The phenomenological distinction between quasi-parallel and quasi-perpendicular shocks that has emerged from bow shock research; present efforts to extend this work to interplanetary shocks; theories of particle acceleration by shocks; and particle acceleration to shock structures using multiple fluid models were discussed.

Experimental analysis of 7.62 mm hydrodynamic ram in containers

NASA Astrophysics Data System (ADS)

Deletombe, E.; Fabis, J.; Dupas, J.; Mortier, J. M.

2013-02-01

The design of fuel tanks with a reduced vulnerability with respect to hydrodynamic ram pressure (HRAM) effects is of an increasing need in the Civil (e.g. the Concorde accident), and Defence (military aircraft, unmanned vehicle systems) aircraft industries. The presented work concerns experimental research which aims at observing two hydraulic ram events - both induced by a 7.62 mm bullet shot in very different containers - throughout their various steps until the final collapse of the generated cavity, in order to study the nature of HRAM, the influence of the containers geometry, and to measure original dynamic data for numerical modelling developments and validation. For that purpose, test configurations and experimental results are described, documented and discussed. They concern two types of firing tests that were performed at ONERA using the NATO 7.62 mm projectile, respectively in the frame of ONERA (pool) and EUCLID (caisson) funded research projects. The authors concentrate on two topics: on the one hand, digital image analysis to measure the cavity geometry during its growth and collapse phases and, on the other hand, pressure measurements that catch the transient shock wave. The originality of the work consists in the fact that - compared with other published works - the phenomenon is studied up to tens of milliseconds in a very large pool for theoretical analysis of the bullet/liquid interactions only, and in a realistic fuel tank specimen to consider influence of boundary conditions onto the cavity characteristics (geometry, dynamics).

New method for detecting singularities in experimental incompressible flows

NASA Astrophysics Data System (ADS)

Kuzzay, Denis; Saw, Ewe-Wei; Martins, Fabio J. W. A.; Faranda, Davide; Foucaut, Jean-Marc; Daviaud, François; Dubrulle, Bérengère

2017-06-01

We introduce two new criteria based on the work of Duchon and Robert (2000 Nonlinearity 13 249) and Eyink (2006 Phys. Rev. E 74 066302), which allow for the local detection of Navier-Stokes singularities in experimental flows. We discuss the difference between non-dissipative or dissipative Euler quasi-singularities and genuine Navier-Stokes dissipative singularites, and classify them with respect to their Hölder exponent h. We show that our criteria allow us to detect areas in a flow where the velocity field is no more regular than Hölder continuous with some Hölder exponent h ≤slant 1/2 . We illustrate our discussion using classical tomographic particle image velocimetry (TPIV) measurements obtained inside a high Reynolds number flow generated in the boundary layer of a wind tunnel. Our study shows that, in order to detect singularities or quasi-singularities, one does not need to have access to the whole velocity field inside a volume, but can instead look for them from stereoscopic PIV data on a plane. We also provide a discussion about the link between areas detected by our criteria and areas corresponding to large vorticity. We argue that this link might provide either a clue about the genesis of these quasi-singularities or a way to discriminate dissipative Euler quasi-singularities and genuine Navier-Stokes singularities.

Scaffolding scientific discussion using socially relevant representations in networked multimedia

NASA Astrophysics Data System (ADS)

Hoadley, Christopher M.

1999-11-01

How do students make use of social cues when learning on the computer? This work examines how students in a middle-school science course learned through on-line peer discussion. Cognitive accounts of collaboration stress interacting with ideas, while socially situated accounts stress the interpersonal context. The design of electronic environments allows investigation into the interrelation of cognitive and social dimensions. I use on-line peer discussion to investigate how socially relevant representations in interfaces can aid learning. First, I identify some of the variables that affect individual participation in on-line discussion, including interface features. Individual participation is predicted by student attitudes towards learning from peers. Second, I describe the range of group outcomes for these on-line discussions. There is a large effect of discussion group on learning outcomes which is not reducible to group composition or gross measures of group process. Third, I characterize how students (individually) construct understanding from these group discussions. Learning in the on-line discussions is shown to be a result of sustained interaction over time, not merely encountering or expressing ideas. Experimental manipulations in the types of social cues available to students suggest that many students do use socially relevant representations to support their understanding of multiple viewpoints and science reasoning. Personalizing scientific disputes can afford reflection on the nature of scientific discovery and advance. While there are many individual differences in how social representations are used by students in learning, overall learning benefits for certain social representations can be shown. This work has profound implications for design of collaborative instructional methods, equitable access to science learning, design of instructional technology, and understanding of learning and cognition in social settings.

Development of a Proof of Concept Low Temperature Superfluid Magnetic Pump with Applications

NASA Astrophysics Data System (ADS)

Jahromi, Amir E.

State of the art particle and photon detectors such as Transition Edge Sensors (TES) and Microwave Kinetic Inductance Detectors (MKID) use large arrays of sensors or detectors for space science missions. As the size of these space science detectors increases, future astrophysics missions will require sub-Kelvin coolers over larger areas. This leads to not only increased cooling power requirements, but also a requirement for distributed sub-Kelvin cooling. Development of a proof of concept Superfluid Magnetic Pump is discussed in this work. This novel low temperature, no moving part pump can replace the existing bellows-piston driven 4He or 3He- 4He mixture compressor/circulators used in various sub Kelvin refrigeration systems such as dilution, Superfluid pulse tube, or active magnetic regenerative refrigerators. Due to its superior thermal transport properties this pump can also be used as a simple circulator of sub-Lambda 4He to distribute cooling over large surface areas. The pump discussed in this work was experimentally shown to produce a maximum flow rate of 440 mg/s (averaged over cycle), 665 mg/s (peak) and produced a maximum pressure difference of 2323 Pascal. This pump worked in an "ideal" thermodynamic state: The experimental results matched with the theoretical values predicted by a computer model. Pump curves were developed to map the performance of this pump. This successful demonstration will enable this novel pump to be put to test in suitable sub Kelvin refrigeration systems. Numerical modeling of an Active Magnetic Regenerative Refrigerator (AMRR) that uses the Superfluid Magnetic Pump (SMP) to circulate liquid 3He-4He through a magnetic regenerator is presented as a potential application of such a pump.

Impact characteristics for high-pressure large-flow water-based emulsion pilot operated check valve reverse opening

NASA Astrophysics Data System (ADS)

Liu, Lei; Huang, Chuanhui; Yu, Ping; Zhang, Lei

2017-10-01

To improve the dynamic characteristics and cavitation characteristics of large-flow pilot operated check valve, consider the pilot poppet as the research object, analyses working principle and design three different kinds of pilot poppets. The vibration characteristics and impact characteristics are analyzed. The simulation model is established through flow field simulation software. The cavitation characteristics of large-flow pilot operated check valve are studied and discussed. On this basis, high-pressure large-flow impact experimental system is used for impact experiment, and the cavitation index is discussed. Then optimal structure is obtained. Simulation results indicate that the increase of pilot poppet half cone angle can effectively reduce the cavitation area, reducing the generation of cavitation. Experimental results show that the pressure impact is not decreasing with increasing of pilot poppet half cone angle in process of unloading, but the unloading capacity, response speed and pilot poppet half cone angle are positively correlated. The impact characteristics of 60° pilot poppet, and its cavitation index is lesser, which indicates 60° pilot poppet is the optimal structure, with the theory results are basically identical.

Determination of the temperature distribution in a minichannel using ANSYS CFX and a procedure based on the Trefftz functions

NASA Astrophysics Data System (ADS)

Maciejewska, Beata; Błasiak, Sławomir; Piasecka, Magdalena

This work discusses the mathematical model for laminar-flow heat transfer in a minichannel. The boundary conditions in the form of temperature distributions on the outer sides of the channel walls were determined from experimental data. The data were collected from the experimental stand the essential part of which is a vertical minichannel 1.7 mm deep, 16 mm wide and 180 mm long, asymmetrically heated by a Haynes-230 alloy plate. Infrared thermography allowed determining temperature changes on the outer side of the minichannel walls. The problem was analysed numerically through either ANSYS CFX software or special calculation procedures based on the Finite Element Method and Trefftz functions in the thermal boundary layer. The Trefftz functions were used to construct the basis functions. Solutions to the governing differential equations were approximated with a linear combination of Trefftz-type basis functions. Unknown coefficients of the linear combination were calculated by minimising the functional. The results of the comparative analysis were represented in a graphical form and discussed.

Dynamic causal modelling: a critical review of the biophysical and statistical foundations.

PubMed

Daunizeau, J; David, O; Stephan, K E

2011-09-15

The goal of dynamic causal modelling (DCM) of neuroimaging data is to study experimentally induced changes in functional integration among brain regions. This requires (i) biophysically plausible and physiologically interpretable models of neuronal network dynamics that can predict distributed brain responses to experimental stimuli and (ii) efficient statistical methods for parameter estimation and model comparison. These two key components of DCM have been the focus of more than thirty methodological articles since the seminal work of Friston and colleagues published in 2003. In this paper, we provide a critical review of the current state-of-the-art of DCM. We inspect the properties of DCM in relation to the most common neuroimaging modalities (fMRI and EEG/MEG) and the specificity of inference on neural systems that can be made from these data. We then discuss both the plausibility of the underlying biophysical models and the robustness of the statistical inversion techniques. Finally, we discuss potential extensions of the current DCM framework, such as stochastic DCMs, plastic DCMs and field DCMs. Copyright © 2009 Elsevier Inc. All rights reserved.

Quantitative Aspects of Single Molecule Microscopy

PubMed Central

Ober, Raimund J.; Tahmasbi, Amir; Ram, Sripad; Lin, Zhiping; Ward, E. Sally

2015-01-01

Single molecule microscopy is a relatively new optical microscopy technique that allows the detection of individual molecules such as proteins in a cellular context. This technique has generated significant interest among biologists, biophysicists and biochemists, as it holds the promise to provide novel insights into subcellular processes and structures that otherwise cannot be gained through traditional experimental approaches. Single molecule experiments place stringent demands on experimental and algorithmic tools due to the low signal levels and the presence of significant extraneous noise sources. Consequently, this has necessitated the use of advanced statistical signal and image processing techniques for the design and analysis of single molecule experiments. In this tutorial paper, we provide an overview of single molecule microscopy from early works to current applications and challenges. Specific emphasis will be on the quantitative aspects of this imaging modality, in particular single molecule localization and resolvability, which will be discussed from an information theoretic perspective. We review the stochastic framework for image formation, different types of estimation techniques and expressions for the Fisher information matrix. We also discuss several open problems in the field that demand highly non-trivial signal processing algorithms. PMID:26167102

Solution of mixed convection heat transfer from isothermal in-line fins

NASA Technical Reports Server (NTRS)

Khalilollahi, Amir

1993-01-01

Transient and steady state combined natural and forced convective flows over two in-line finite thickness fins (louvers) in a vertical channel are numerically solved using two methods. The first method of solution is based on the 'Simple Arbitrary Lagrangian Eulerian' (SALE) technique which incorporates mainly two computational phases: (1) a Lagrangian phase in which the velocity field is updated by the effects of all forces, and (2) an Eulerian phase that executes all advective fluxes of mass, momentum and energy. The second method of solution uses the finite element code entitled FIDAP. In the first part, comparison of the results by FIDAP, SALE, and available experimental work were done and discussed for steady state forced convection over louvered fins. Good agreements were deduced between the three sets of results especially for the flow over a single fin. In the second part and in the absence of experimental literature, the numerical predictions were extended to the transient transports and to the opposing flow where pressure drop is reversed. Results are presented and discussed for heat transfer and pressure drop in assisting and opposing mixed convection flows.

Experimental investigations of turbulent temperature fluctuations and phase angles in ASDEX Upgrade

NASA Astrophysics Data System (ADS)

Freethy, Simon

2017-10-01

A complete experimental understanding of the turbulent fluctuations in tokamak plasmas is essential for providing confidence in the extrapolation of heat transport models to future experimental devices and reactors. Guided by ``predict first'' nonlinear gyrokinetic simulations with the GENE code, two new turbulence diagnostics were designed and have been installed on ASDEX Upgrade (AUG) to probe the fundamentals of ion-scale turbulent electron heat transport. The first, a 30-channel correlation ECE (CECE) radiometer, measures radial profiles (0.5

Quantum simulations and many-body physics with light.

PubMed

Noh, Changsuk; Angelakis, Dimitris G

2017-01-01

In this review we discuss the works in the area of quantum simulation and many-body physics with light, from the early proposals on equilibrium models to the more recent works in driven dissipative platforms. We start by describing the founding works on Jaynes-Cummings-Hubbard model and the corresponding photon-blockade induced Mott transitions and continue by discussing the proposals to simulate effective spin models and fractional quantum Hall states in coupled resonator arrays (CRAs). We also analyse the recent efforts to study out-of-equilibrium many-body effects using driven CRAs, including the predictions for photon fermionisation and crystallisation in driven rings of CRAs as well as other dynamical and transient phenomena. We try to summarise some of the relatively recent results predicting exotic phases such as super-solidity and Majorana like modes and then shift our attention to developments involving 1D nonlinear slow light setups. There the simulation of strongly correlated phases characterising Tonks-Girardeau gases, Luttinger liquids, and interacting relativistic fermionic models is described. We review the major theory results and also briefly outline recent developments in ongoing experimental efforts involving different platforms in circuit QED, photonic crystals and nanophotonic fibres interfaced with cold atoms.

GPS survey of the western Tien Shan

NASA Technical Reports Server (NTRS)

Hager, Bradford H.; Molnar, Peter H.; Hamburger, Michael W.; Reilinger, Robert E.

1995-01-01

There were two major developments in 1994 in our collaborative GPS experiment in the Tien Shan of the Former Soviet Union (FSU). Both were motivated by our expectation that we will ultimately obtain better science at lower cost if we involve our colleagues in the FSU more deeply in (1) the collection and (2) the analysis of data. As an experimental test of the concept of having our local collaborators carry out the field work semi-autonomously, we sent 6 MIT receivers to the Tien Shan for a period of 3 months. To enable our collaborators to have the capability for data analysis, we provided computers for two data analysis centers and organized a two-week training session. This report emphasizes the rationale for deeper involvement of FSU scientists, describes the training sessions, discusses the data collection, and presents the results. We also discuss future plans. More detailed discussion of background, general scientific objectives, discussions with collaborators, and results for the campaigns in 1992 and 1993 have been given in previous reports.

Metallurgical Research Relating to the Development of Metals and Alloys for Use in the High-Temperature Components of Jet-Engines, Gas Turbines and Other Aircraft Propulsion Systems

NASA Technical Reports Server (NTRS)

1948-01-01

Considerable work has been done on report preparation. All items listed in the March program report will be reported during July. Fundamental studies are in progress to establish the fundamental processes by which treatments and composition control properties of commercial alloys at high temperatures. As yet work has been confined to Low-Carbon N155 alloy and progress has been reported twice previously. The work is divided into two sections: studies of solution treated and aged material and studies of rolled structures. Electron microscopic work has been started as an additional technique for the studies. Brief descriptions of experimental techniques used, results, and interpretation of the data obtained since the last report covering this field are summarized below. Since the work outlined is to a large extent still in progress, the discussion given is to be considered tentative and subject to further modification as additional data becomes available.

Theoretical studies of the transport properties in compound semiconductors

NASA Technical Reports Server (NTRS)

Segall, Benjamin

1994-01-01

This final report is an overview of the work done on Cooperative Agreement NCC 3-55 with the Solid State Technology Branch of the NASA-Lewis Research Center (LeRC). Over the period of time that the agreement was in effect, the principal investigator and, in the last three years, the co-principal investigator worked on a significant number of projects and interacted with members of the Solid State Technology (SST) branch in a number of different ways. For the purpose of this report, these efforts will be divided into five categories: 1) work directly with experimental electrical transport studies conducted by members of the SST branch; 2) theoretical work on electrical transport in compound semiconductors; 3) electronic structure calculations which are relevant to the electrical transport in polytypes of SiC and SiC-AlN alloys; 4) the electronic structure calculations of polar interfaces; and 5) consultative and supportive activities related to experiments and other studies carried out by SST branch members. Work in these categories is briefly discussed.

Flow field and friction factor of slush nitrogen in a horizontal circular pipe

NASA Astrophysics Data System (ADS)

Jin, Tao; Li, Yijian; Wu, Shuqin; Wei, Jianjian

2018-04-01

Slush nitrogen is the low-temperature two-phase fluid with solid nitrogen particle suspended in the liquid nitrogen. The flow characteristics of slush nitrogen in a horizontal pipe with the diameter of 16 mm have been experimentally and numerically investigated, under the operating conditions with the inlet flow velocity of 0-4 m/s and the solid volume fraction of 0-23%. The numerical results for pressure drop agree well with those of the experiments, with the relative errors of ±5%. The experimental and numerical results both show that the pressure drop of slush nitrogen is greater than that of subcooled liquid nitrogen and rises with the increasing particle concentration, under the working conditions in present work. Based on the simulation result, the flow pattern evolution of slush nitrogen with the increasing slush Reynolds number has been discussed, which can be classified into homogenous flow, heterogeneous flow and moving bed. The slush effective viscosity and the slush Reynolds number are calculated with Cheng & Law formula, which includes the effects of particle shape, size and type and has a high accuracy for high concentration slurries. Based on the slush Reynolds number, an experimental empirical correlation considering particle conditions for the friction factor of slush nitrogen flow is obtained.

Is the kinetoplast DNA a percolating network of linked rings at its critical point?

NASA Astrophysics Data System (ADS)

Michieletto, Davide; Marenduzzo, Davide; Orlandini, Enzo

2015-05-01

In this work we present a computational study of the kinetoplast genome, modelled as a large number of semiflexible unknotted loops, which are allowed to link with each other. As the DNA density increases, the systems shows a percolation transition between a gas of unlinked rings and a network of linked loops which spans the whole system. Close to the percolation transition, we find that the mean valency of the network, i.e. the average number of loops which are linked to any one loop, is around three, as found experimentally for the kinetoplast DNA (kDNA). Even more importantly, by simulating the digestion of the network by a restriction enzyme, we show that the distribution of oligomers, i.e. structures formed by a few loops which remain linked after digestion, quantitatively matches experimental data obtained from gel electrophoresis, provided that the density is, once again, close to the percolation transition. With respect to previous work, our analysis builds on a reduced number of assumptions, yet can still fully explain the experimental data. Our findings suggest that the kDNA can be viewed as a network of linked loops positioned very close to the percolation transition, and we discuss the possible biological implications of this remarkable fact.

Stable isotopes and elasmobranchs: tissue types, methods, applications and assumptions.

PubMed

Hussey, N E; MacNeil, M A; Olin, J A; McMeans, B C; Kinney, M J; Chapman, D D; Fisk, A T

2012-04-01

Stable-isotope analysis (SIA) can act as a powerful ecological tracer with which to examine diet, trophic position and movement, as well as more complex questions pertaining to community dynamics and feeding strategies or behaviour among aquatic organisms. With major advances in the understanding of the methodological approaches and assumptions of SIA through dedicated experimental work in the broader literature coupled with the inherent difficulty of studying typically large, highly mobile marine predators, SIA is increasingly being used to investigate the ecology of elasmobranchs (sharks, skates and rays). Here, the current state of SIA in elasmobranchs is reviewed, focusing on available tissues for analysis, methodological issues relating to the effects of lipid extraction and urea, the experimental dynamics of isotopic incorporation, diet-tissue discrimination factors, estimating trophic position, diet and mixing models and individual specialization and niche-width analyses. These areas are discussed in terms of assumptions made when applying SIA to the study of elasmobranch ecology and the requirement that investigators standardize analytical approaches. Recommendations are made for future SIA experimental work that would improve understanding of stable-isotope dynamics and advance their application in the study of sharks, skates and rays. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Mutual solubility of water and structural/positional isomers of N-alkylpyridinium-based ionic liquids.

PubMed

Freire, Mara G; Neves, Catarina M S S; Shimizu, Karina; Bernardes, Carlos E S; Marrucho, Isabel M; Coutinho, João A P; Canongia Lopes, José N; Rebelo, Luís Paulo N

2010-12-09

Despite many previous important contributions to the characterization of the liquid-liquid phase behavior of ionic liquids (ILs) plus water systems, a gap still exists as far as the effect of isomers (of ILs) is concerned. Therefore, in this work, a comprehensive study of the liquid-liquid equilibria between water and isomeric pyridinium-based ionic liquids has been performed. Atmospheric pressure mutual solubilities between water and pyridinium-based ionic liquids combined with the common anion bis[(trifluoromethyl)sulfonyl]imide were experimentally determined between (288.15 and 318.15) K. The main goal of this work is to study the isomeric effects on the pyridinium-based cation, namely, the structural and positional isomerism, as well as the alkyl side chain length. To the best of our knowledge, the influence of both structural and positional isomerism on the liquid-liquid behavior in ionic-liquid-water-containing systems is an unexplored field and is here assessed for the first time. Moreover, from the experimental solubility data, several infinite dilution molar thermodynamic functions of solution, namely, the Gibbs energy, the enthalpy, and the entropy, were estimated and discussed. In addition, aiming at gathering a broader picture of the underlying thermodynamic solvation phenomenon, molecular dynamics simulations were also carried out for the same experimental systems.

ORBIT modelling of fast particle redistribution induced by sawtooth instability

NASA Astrophysics Data System (ADS)

Kim, Doohyun; Podestà, Mario; Poli, Francesca; Princeton Plasma Physics Laboratory Team

2017-10-01

Initial tests on NSTX-U show that introducing energy selectivity for sawtooth (ST) induced fast ion redistribution improves the agreement between experimental and simulated quantities, e.g. neutron rate. Thus, it is expected that a proper description of the fast particle redistribution due to ST can improve the modelling of ST instability and interpretation of experiments using a transport code. In this work, we use ORBIT code to characterise the redistribution of fast particles. In order to simulate a ST crash, a spatial and temporal displacement is implemented as ξ (ρ , t , θ , ϕ) = ∑ξmn (ρ , t) cos (mθ + nϕ) to produce perturbed magnetic fields from the equilibrium field B-> , δB-> = ∇ × (ξ-> × B->) , which affect the fast particle distribution. From ORBIT simulations, we find suitable amplitudes of ξ for each ST crash to reproduce the experimental results. The comparison of the simulation and the experimental results will be discussed as well as the dependence of fast ion redistribution on fast ion phase space variables (i.e. energy, magnetic moment and toroidal angular momentum). Work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences under Contract Number DE-AC02-09CH11466.

Photonic crystal Fano resonances for realizing optical switches, lasers, and non-reciprocal elements

NASA Astrophysics Data System (ADS)

Bekele, Dagmawi A.; Yu, Yi; Hu, Hao; Ding, Yunhong; Sakanas, Aurimas; Ottaviano, Luisa; Semenova, Elizaveta; Oxenløwe, Leif K.; Yvind, Kresten; Mork, Jesper

2017-08-01

We present our work on photonic crystal membrane devices exploiting Fano resonance between a line-defect waveguide and a side coupled nanocavity. Experimental demonstration of fast and compact all-optical switches for wavelength-conversion is reported. It is shown how the use of an asymmetric structure in combination with cavity-enhanced nonlinearity can be used to realize non-reciprocal transmission at ultra-low power and with large bandwidth. A novel type of laser structure, denoted a Fano laser, is discussed in which one of the mirrors is based on a Fano resonance. Finally, the design, fabrication and characterization of grating couplers for efficient light coupling in and out of the indium phosphide photonic crystal platform is discussed.

Optical analysis of high power free electron laser resonators

NASA Astrophysics Data System (ADS)

Knapp, C. E.; Viswanathan, V. K.; Appert, Q. D.; Bender, S. C.; McVey, B. D.

1987-06-01

The first part of this paper briefly describes the optics code used at Los Alamos National Laboratory to do optical analyses of various components of a free electron laser. The body of the paper then discusses the recent results in modeling low frequency gratings and ripple on the surfaces of liquid-cooled mirrors. The ripple is caused by structural/thermal effects in the mirror surface due to heating by optical absorption in high power resonators. Of interest is how much ripple can be permitted before diffractive losses or optical mode distortions become unacceptable. Preliminary work is presented involving classical diffraction problems to support the ripple study. The limitations of the techniques are discussed and the results are compared to experimental results where available.

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

Berkelbach, Timothy C., E-mail: tcb2112@columbia.edu; Reichman, David R., E-mail: drr2103@columbia.edu; Hybertsen, Mark S., E-mail: mhyberts@bnl.gov

We extend our previous work on singlet exciton fission in isolated dimers to the case of crystalline materials, focusing on pentacene as a canonical and concrete example. We discuss the proper interpretation of the character of low-lying excited states of relevance to singlet fission. In particular, we consider a variety of metrics for measuring charge-transfer character, conclusively demonstrating significant charge-transfer character in the low-lying excited states. The impact of this electronic structure on the subsequent singlet fission dynamics is assessed by performing real-time master-equation calculations involving hundreds of quantum states. We make direct comparisons with experimental absorption spectra and singletmore » fission rates, finding good quantitative agreement in both cases, and we discuss the mechanistic distinctions that exist between small isolated aggregates and bulk systems.« less

Entanglement dynamics in itinerant fermionic and bosonic systems

NASA Astrophysics Data System (ADS)

Pillarishetty, Durganandini

2017-04-01

The concept of quantum entanglement of identical particles is fundamental in a wide variety of quantum information contexts involving composite quantum systems. However, the role played by particle indistinguishabilty in entanglement determination is being still debated. In this work, we study, theoretically, the entanglement dynamics in some itinerant bosonic and fermionic systems. We show that the dynamical behaviour of particle entanglement and spatial or mode entanglement are in general different. We also discuss the effect of fermionic and bosonic statistics on the dynamical behaviour. We suggest that the different dynamical behaviour can be used to distinguish between particle and mode entanglement in identical particle systems and discuss possible experimental realizations for such studies. I acknowledge financial support from DST, India through research Grant.

RRAM-based hardware implementations of artificial neural networks: progress update and challenges ahead

NASA Astrophysics Data System (ADS)

Prezioso, M.; Merrikh-Bayat, F.; Chakrabarti, B.; Strukov, D.

2016-02-01

Artificial neural networks have been receiving increasing attention due to their superior performance in many information processing tasks. Typically, scaling up the size of the network results in better performance and richer functionality. However, large neural networks are challenging to implement in software and customized hardware are generally required for their practical implementations. In this work, we will discuss our group's recent efforts on the development of such custom hardware circuits, based on hybrid CMOS/memristor circuits, in particular of CMOL variety. We will start by reviewing the basics of memristive devices and of CMOL circuits. We will then discuss our recent progress towards demonstration of hybrid circuits, focusing on the experimental and theoretical results for artificial neural networks based on crossbarintegrated metal oxide memristors. We will conclude presentation with the discussion of the remaining challenges and the most pressing research needs.

Weyl magnons in breathing pyrochlore antiferromagnets

PubMed Central

Li, Fei-Ye; Li, Yao-Dong; Kim, Yong Baek; Balents, Leon; Yu, Yue; Chen, Gang

2016-01-01

Frustrated quantum magnets not only provide exotic ground states and unusual magnetic structures, but also support unconventional excitations in many cases. Using a physically relevant spin model for a breathing pyrochlore lattice, we discuss the presence of topological linear band crossings of magnons in antiferromagnets. These are the analogues of Weyl fermions in electronic systems, which we dub Weyl magnons. The bulk Weyl magnon implies the presence of chiral magnon surface states forming arcs at finite energy. We argue that such antiferromagnets present a unique example, in which Weyl points can be manipulated in situ in the laboratory by applied fields. We discuss their appearance specifically in the breathing pyrochlore lattice, and give some general discussion of conditions to find Weyl magnons, and how they may be probed experimentally. Our work may inspire a re-examination of the magnetic excitations in many magnetically ordered systems. PMID:27650053

Weyl magnons in breathing pyrochlore antiferromagnets

DOE PAGES

Li, Fei-Ye; Li, Yao-Dong; Kim, Yong Baek; ...

2016-09-21

Frustrated quantum magnets not only provide exotic ground states and unusual magnetic structures, but also support unconventional excitations in many cases. Using a physically relevant spin model for a breathing pyrochlore lattice, we discuss the presence of topological linear band crossings of magnons in antiferromagnets. These are the analogues of Weyl fermions in electronic systems, which we dub Weyl magnons. The bulk Weyl magnon implies the presence of chiral magnon surface states forming arcs at finite energy. We argue that such antiferromagnets present a unique example, in which Weyl points can be manipulated in situ in the laboratory by appliedmore » fields. We discuss their appearance specifically in the breathing pyrochlore lattice, and give some general discussion of conditions to find Weyl magnons, and how they may be probed experimentally. Our work may inspire a re-examination of the magnetic excitations in many magnetically ordered systems.« less

Stochastic memory: getting memory out of noise

NASA Astrophysics Data System (ADS)

Stotland, Alexander; di Ventra, Massimiliano

2011-03-01

Memory circuit elements, namely memristors, memcapacitors and meminductors, can store information without the need of a power source. These systems are generally defined in terms of deterministic equations of motion for the state variables that are responsible for memory. However, in real systems noise sources can never be eliminated completely. One would then expect noise to be detrimental for memory. Here, we show that under specific conditions on the noise intensity memory can actually be enhanced. We illustrate this phenomenon using a physical model of a memristor in which the addition of white noise into the state variable equation improves the memory and helps the operation of the system. We discuss under which conditions this effect can be realized experimentally, discuss its implications on existing memory systems discussed in the literature, and also analyze the effects of colored noise. Work supported in part by NSF.

On the relative utility of infrared (IR) versus terahertz (THz) for optical sensors

NASA Astrophysics Data System (ADS)

Johnson, T. J.; Valentine, N. B.; Gassman, P. L.; Atkinson, D. A.; Sharpe, S. W.; Williams, Steven D.

2007-09-01

Pacific Northwest National Laboratory (PNNL) has active programs investigating the optical absorption strengths of several types of molecules including toxic industrial chemicals (TICs), microbiological threats such as bacteria, as well as explosives such as RDX, PETN and TNT. While most of our work has centered on the mid-infrared domain (600 to 6,500 cm-1), more recent work has also included work in the far-infrared, also called the terahertz (THz) region (500 to ~8 cm-1). Using Fourier transform infrared spectroscopy, we have been able to compare the relative, and in some cases absolute, IR/THz cross sections of a number of species in the solid and liquid phases. The relative band strengths of a number of species of interest are discussed in terms of both experimental and computational results.

Wet Work and Barrier Function.

PubMed

Fartasch, Manigé

2016-01-01

Wet work defined as unprotected exposure to humid environments/water; high frequencies of hand washing procedures or prolonged glove occlusion is believed to cause irritant contact dermatitis in a variety of occupations. This review considers the recent studies on wet-work exposure and focuses on its influence on barrier function. There are different methods to study the effect of wet work on barrier function. On the one hand, occupational cohorts at risk can be monitored prospectively by skin bioengineering technology and clinical visual scoring systems; on the other hand, experimental test procedures with defined application of water, occlusion and detergents are performed in healthy volunteers. Both epidemiological studies and the results of experimental procedures are compared and discussed. A variety of epidemiological studies analyze occupational cohorts at risk. The measurement of transepidermal water loss, an indicator of the integrity of the epidermal barrier, and clinical inspection of the skin have shown that especially the frequencies of hand washing and water contact/contact to aqueous mixtures seem to be the main factors for the occurrence of barrier alterations. On the other hand, in a single cross-sectional study, prolonged glove wearing (e.g. occlusion for 6 h per shift in clean-room workers) without exposure to additional hazardous substances seemed not to affect the skin negatively. But regarding the effect of occlusion, there is experimental evidence that previously occluded skin challenged with sodium lauryl sulfate leads to an increased susceptibility to the irritant with an aggravation of the irritant reaction. These findings might have relevance for the real-life situation in so far as after occupational glove wearing, the skin is more susceptible to potential hazards to the skin even during leisure hours. © 2016 S. Karger AG, Basel.

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

Perl, M.L.

This paper is based upon lectures in which I have described and explored the ways in which experimenters can try to find answers, or at least clues toward answers, to some of the fundamental questions of elementary particle physics. All of these experimental techniques and directions have been discussed fully in other papers, for example: searches for heavy charged leptons, tests of quantum chromodynamics, searches for Higgs particles, searches for particles predicted by supersymmetric theories, searches for particles predicted by technicolor theories, searches for proton decay, searches for neutrino oscillations, monopole searches, studies of low transfer momentum hadron physics atmore » very high energies, and elementary particle studies using cosmic rays. Each of these subjects requires several lectures by itself to do justice to the large amount of experimental work and theoretical thought which has been devoted to these subjects. My approach in these tutorial lectures is to describe general ways to experiment beyond the standard model. I will use some of the topics listed to illustrate these general ways. Also, in these lectures I present some dreams and challenges about new techniques in experimental particle physics and accelerator technology, I call these Experimental Needs. 92 references.« less

Experimental Characterization of Piezoelectric Radial Field Diaphragms for Fluidic Control

NASA Technical Reports Server (NTRS)

Bryant, R. G.; Kavli, S. E.; Thomas, R. A., Jr.; Darji, K. J.; Mossi, K. M.

2004-01-01

NASA has recently developed a new piezoelectric actuator, the Radial Field Diaphragm or RFD. This actuator uses a radially-directed electric field to generate concentric out-of-plane (Z-axis) motion that allows this packaged device to be used as a pump or valve diaphragm. In order to efficiently use this new active device, experimental determination of pressure, flow rate, mechanical work, power consumption and overall efficiency needs to be determined by actually building a pump. However, without an optimized pump design, it is difficult to assess the quality of the data, as these results are inherent to the actual pump. Hence, separate experiments must be conducted in order to generate independent results to help guide the design criteria and pump quality. This paper focuses on the experiments used to generate the RFD's operational parameters and then compares these results to the experimentally determined results of several types of ball pumps. Also discussed are how errors are inherently introduced into the experiments, the pump design, experimental hardware and their effects on the overall system efficiency.

TGT for chemistry learning to enhance students' achievement and critical thinking skills

NASA Astrophysics Data System (ADS)

Bolhassan, Norlailatulakma; Taha, Hafsah

2017-05-01

The form of cooperative learning known as Teams-Games-Tournament (TGT) in this study favors the use of teams work and learning tools combined with student play and practice to foster students' achievement and critical thinking skills. Using this paradigm, this study incorporates Teams-Games-Tournament and Flash Cards Games Kit during an 8-weeks experimental instruction period that includes 67 Form Four students; 34 students in the experimental group and 33 in the control group. The learning design in experimental group emphasizes scaffolding, guided practices, cooperative learning, and active participation in learning. While the experimental group experienced the TGT approach, the control group encountered the conventional teaching approach of chemistry drills. An achievement chemistry test and Watson Glaser Critical Thinking Appraisal (WGCTA) were used for the pretest and posttest. The finding indicates that TGT learning was more effective than drills in promoting chemistry performance, and the playful competiveness among students promotes students' critical thinking. In addition, TGT cooperative learning also creates an active learning environment in solving problems and discussions among students and teachers.

Evaluation of Test Methods for Triaxially Braided Composites using a Meso-Scale Finite Element Model

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

Zhang, Chao

The characterization of triaxially braided composite is complicate due to the nonuniformity of deformation within the unit cell as well as the possibility of the freeedge effect related to the large size of the unit cell. Extensive experimental investigation has been conducted to develop more accurate test approaches in characterizing the actual mechanical properties of the material we are studying. In this work, a meso-scale finite element model is utilized to simulate two complex specimens: notched tensile specimen and tube tensile specimen, which are designed to avoid the free-edge effect and free-edge effect induced premature edge damage. The full fieldmore » strain data is predicted numerically and compared with experimental data obtained by Digit Image Correlation. The numerically predicted tensile strength values are compared with experimentally measured results. The discrepancy between numerically predicted and experimentally measured data, the capability of different test approaches are analyzed and discussed. The presented numerical model could serve as assistance to the evaluation of different test methods, and is especially useful in identifying potential local damage events.« less

Quantitative Determination of Isotope Ratios from Experimental Isotopic Distributions

PubMed Central

Kaur, Parminder; O’Connor, Peter B.

2008-01-01

Isotope variability due to natural processes provides important information for studying a variety of complex natural phenomena from the origins of a particular sample to the traces of biochemical reaction mechanisms. These measurements require high-precision determination of isotope ratios of a particular element involved. Isotope Ratio Mass Spectrometers (IRMS) are widely employed tools for such a high-precision analysis, which have some limitations. This work aims at overcoming the limitations inherent to IRMS by estimating the elemental isotopic abundance from the experimental isotopic distribution. In particular, a computational method has been derived which allows the calculation of 13C/12C ratios from the whole isotopic distributions, given certain caveats, and these calculations are applied to several cases to demonstrate their utility. The limitations of the method in terms of the required number of ions and S/N ratio are discussed. For high-precision estimates of the isotope ratios, this method requires very precise measurement of the experimental isotopic distribution abundances, free from any artifacts introduced by noise, sample heterogeneity, or other experimental sources. PMID:17263354

Biotic games and cloud experimentation as novel media for biophysics education

NASA Astrophysics Data System (ADS)

Riedel-Kruse, Ingmar; Blikstein, Paulo

2014-03-01

First-hand, open-ended experimentation is key for effective formal and informal biophysics education. We developed, tested and assessed multiple new platforms that enable students and children to directly interact with and learn about microscopic biophysical processes: (1) Biotic games that enable local and online play using galvano- and photo-tactic stimulation of micro-swimmers, illustrating concepts such as biased random walks, Low Reynolds number hydrodynamics, and Brownian motion; (2) an undergraduate course where students learn optics, electronics, micro-fluidics, real time image analysis, and instrument control by building biotic games; and (3) a graduate class on the biophysics of multi-cellular systems that contains a cloud experimentation lab enabling students to execute open-ended chemotaxis experiments on slimemolds online, analyze their data, and build biophysical models. Our work aims to generate the equivalent excitement and educational impact for biophysics as robotics and video games have had for mechatronics and computer science, respectively. We also discuss how scaled-up cloud experimentation systems can support MOOCs with true lab components and life-science research in general.

Determinants of shortened, disrupted, and mistimed sleep and associated metabolic health consequences in healthy humans.

PubMed

Cedernaes, Jonathan; Schiöth, Helgi B; Benedict, Christian

2015-04-01

Recent increases in the prevalence of obesity and type 2 diabetes mellitus (T2DM) in modern societies have been paralleled by reductions in the time their denizens spend asleep. Epidemiological studies have shown that disturbed sleep-comprising short, low-quality, and mistimed sleep-increases the risk of metabolic diseases, especially obesity and T2DM. Supporting a causal role of disturbed sleep, experimental animal and human studies have found that sleep loss can impair metabolic control and body weight regulation. Possible mechanisms for the observed changes comprise sleep loss-induced changes in appetite-signaling hormones (e.g., higher levels of the hunger-promoting hormone ghrelin) or hedonic brain responses, altered responses of peripheral tissues to metabolic signals, and changes in energy intake and expenditure. Even though the overall consensus is that sleep loss leads to metabolic perturbations promoting the development of obesity and T2DM, experimental evidence supporting the validity of this view has been inconsistent. This Perspective aims at discussing molecular to behavioral factors through which short, low-quality, and mistimed sleep may threaten metabolic public health. In this context, possible factors that may determine the extent to which poor sleep patterns increase the risk of metabolic pathologies within and across generations will be discussed (e.g., timing and genetics). © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Pressure Scalings and Influence Region Research

DTIC Science & Technology

2018-01-01

the results are briefly discussed. Additionally, updated experimental results are presented along with discussion of collaborative research efforts...with upstream and downstream influence, where the influence lengths are defined in terms of a-priori quantities (freestream conditions and...governing equations and the result is briefly discussed. Additionally, updated experimental results are presented along with discussion of

Evolution of sex: Using experimental genomics to select among competing theories.

PubMed

Sharp, Nathaniel P; Otto, Sarah P

2016-08-01

Few topics have intrigued biologists as much as the evolution of sex. Understanding why sex persists despite its costs requires not just rigorous theoretical study, but also empirical data on related fundamental issues, including the nature of genetic variance for fitness, patterns of genetic interactions, and the dynamics of adaptation. The increasing feasibility of examining genomes in an experimental context is now shedding new light on these problems. Using this approach, McDonald et al. recently demonstrated that sex uncouples beneficial and deleterious mutations, allowing selection to proceed more effectively with sex than without. Here we discuss the insights provided by this study, along with other recent empirical work, in the context of the major theoretical models for the evolution of sex. © 2016 WILEY Periodicals, Inc.

Re-designing a mechanism for higher speed: A case history from textile machinery

NASA Astrophysics Data System (ADS)

Douglas, S. S.; Rooney, G. T.

The generation of general mechanism design software which is the formulation of suitable objective functions is discussed. There is a consistent drive towards higher speeds in the development of industrial sewing machines. This led to experimental analyses of dynamic performance and to a search for improved design methods. The experimental work highlighted the need for smoothness of motion at high speed, component inertias, and frame structural stiffness. Smoothness is associated with transmission properties and harmonic analysis. These are added to other design requirements of synchronization, mechanism size, and function. Some of the mechanism trains in overedte sewing machines are shown. All these trains are designed by digital optimization. The design software combines analysis of the sewing machine mechanisms, formulation of objectives innumerical terms, and suitable mathematical optimization ttechniques.

Advanced electric propulsion research, 1989

NASA Technical Reports Server (NTRS)

Wilbur, Paul J.

1990-01-01

Results of an experimental study of the characteristics of ion thruster hollow cathodes operating at high discharge currents (up to 60 A) are presented in a companion report. This work shows that ions produced near the cathode orifice can acquire sufficient energy to induce the high sputter erosion rates on cathode potential surfaces that have been observed in ion thrusters. A mechanism by which these ions could be produced is also described. A second, brief study showing how a discharge chamber model developed previously can be applied to determine optimal values for one or more discharge chamber design parameters is presented. The experimental approach being used to study the plasma potential field and charge-exchange ion production rate downstream of the accelerator grid of an ion thruster is discussed and preliminary results are presented.

Structure and properties of CaMnO3/SrMnO3/BaMnO3 superlattices from first principles

NASA Astrophysics Data System (ADS)

Li, Shen; Oh, Seongshik; Rabe, Karin

2008-03-01

Previous theoretical and experimental studies have shown that three-component, or ``tri-color'' superlattices can exhibit intrinsic electric polarization due to inversion-symmetry breaking in the layer sequence. In ferromagnetic inversion-symmetry-breaking superlattices, controlled symmetry lowering is similarly expected to lead to interesting new and tunable properties. Here, we present results of first-principles density-functional-theory calculations for short-period CaMnO3/SrMnO3/BaMnO3 superlattices, using VASP. The ground state structure, magnetic ordering, polarization and dielectric response will be presented. The role of epitaxial strain in the individual layers and the role of layer sequence will be explored. Connections to experimental studies and prospects for future work will be discussed.

Torque Transient of Magnetically Drive Flow for Viscosity Measurement

NASA Technical Reports Server (NTRS)

Ban, Heng; Li, Chao; Su, Ching-Hua; Lin, Bochuan; Scripa, Rosalia N.; Lehoczky, Sandor L.

2004-01-01

Viscosity is a good indicator of structural changes for complex liquids, such as semiconductor melts with chain or ring structures. This paper discusses the theoretical and experimental results of the transient torque technique for non-intrusive viscosity measurement. Such a technique is essential for the high temperature viscosity measurement of high pressure and toxic semiconductor melts. In this paper, our previous work on oscillating cup technique was expanded to the transient process of a magnetically driven melt flow in a damped oscillation system. Based on the analytical solution for the fluid flow and cup oscillation, a semi-empirical model was established to extract the fluid viscosity. The analytical and experimental results indicated that such a technique has the advantage of short measurement time and straight forward data analysis procedures

Large area sheet task: Advanced dendritic web growth development

NASA Technical Reports Server (NTRS)

Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Hopkins, R. H.; Meier, D.; Schruben, J.

1981-01-01

The growth of silicon dendritic web for photovoltaic applications was investigated. The application of a thermal model for calculating buckling stresses as a function of temperature profile in the web is discussed. Lid and shield concepts were evaluated to provide the data base for enhancing growth velocity. An experimental web growth machine which embodies in one unit the mechanical and electronic features developed in previous work was developed. In addition, evaluation of a melt level control system was begun, along with preliminary tests of an elongated crucible design. The economic analysis was also updated to incorporate some minor cost changes. The initial applications of the thermal model to a specific configuration gave results consistent with experimental observation in terms of the initiation of buckling vs. width for a given crystal thickness.

A technique for measurement of instantaneous heat transfer in steady-flow ambient-temperature facilities

NASA Technical Reports Server (NTRS)

O'Brien, James E.

1990-01-01

An experimental technique is described for obtaining time-resolved heat flux measurements with high-frequency response (up to 100 kHz) in a steady-flow ambient-temperature facility. The heat transfer test object is preheated and suddenly injected into an established steady flow. Thin-film gages deposited on the test surface detect the unsteady substrate surface temperature. Analog circuitry designed for use in short-duration facilities and based on one-dimensional semiinfinite heat conduction is used to perform the temperature/heat flux transformation. A detailed description of substrate properties, instrumentation, experimental procedure, and data reduction is given, along with representative results obtained in the stagnation region of a circular cylinder subjected to a wake-dominated unsteady flow. An in-depth discussion of related work is also provided.

Numerical and experimental investigation of melting with internal heat generation within cylindrical enclosures

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

Amber Shrivastava; Brian Williams; Ali S. Siahpush

2014-06-01

There have been significant efforts by the heat transfer community to investigate the melting phenomenon of materials. These efforts have included the analytical development of equations to represent melting, numerical development of computer codes to assist in modeling the phenomena, and collection of experimental data. The understanding of the melting phenomenon has application in several areas of interest, for example, the melting of a Phase Change Material (PCM) used as a thermal storage medium as well as the melting of the fuel bundle in a nuclear power plant during an accident scenario. The objective of this research is two-fold. Firstmore » a numerical investigation, using computational fluid dynamics (CFD), of melting with internal heat generation for a vertical cylindrical geometry is presented. Second, to the best of authors knowledge, there are very limited number of engineering experimental results available for the case of melting with Internal Heat Generation (IHG). An experiment was performed to produce such data using resistive, or Joule, heating as the IHG mechanism. The numerical results are compared against the experimental results and showed favorable correlation. Uncertainties in the numerical and experimental analysis are discussed. Based on the numerical and experimental analysis, recommendations are made for future work.« less

Achievement goals, self-handicapping, and performance: a 2 x 2 achievement goal perspective.

PubMed

Ntoumanis, Nikos; Thøgersen-Ntoumani, Cecilie; Smith, Alison L

2009-11-01

Elliot and colleagues (2006) examined the effects of experimentally induced achievement goals, proposed by the trichotomous model, on self-handicapping and performance in physical education. Our study replicated and extended the work of Elliot et al. by experimentally promoting all four goals proposed by the 2 x 2 model (Elliot & McGregor, 2001), measuring the participants' own situational achievement goals, using a relatively novel task, and testing the participants in a group setting. We used a randomized experimental design with four conditions that aimed to induce one of the four goals advanced by the 2 x 2 model. The participants (n = 138) were undergraduates who engaged in a dart-throwing task. The results pertaining to self-handicapping partly replicated Elliot and colleagues' findings by showing that experimentally promoted performance-avoidance goals resulted in less practice. In contrast, the promotion of mastery-avoidance goals did not result in less practice compared with either of the approach goals. Dart-throwing performance did not differ among the four goal conditions. Personal achievement goals did not moderate the effects of experimentally induced goals on self-handicapping and performance. The extent to which mastery-avoidance goals are maladaptive is discussed, as well as the interplay between personal and experimentally induced goals.

Experimental observation of magnetoelectricity in spin ice Dy 2Ti 2O 7

DOE PAGES

Lin, L.; Xie, Y. L.; Wen, J. -J.; ...

2015-12-14

The intrinsic noncollinear spin patterns in rare-earth pyrochlore are physically interesting, due to their many emergent properties (e.g., spin-ice and monopole-type excitation). Recent works have suggested that the magnetic monopole excitation of spin-ice systems is magnetoelectric active, but this fact has rarely been confirmed via experiment. In this work, we performed a systematic experimental investigation on the magnetoelectricity of Dy 2Ti 2O 7 by probing the ferroelectricity, spin dynamics, and dielectric behaviors. Two ferroelectric transitions at T c1 = 25 K and T c2 =13 K were observed. Remarkable magnetoelectric coupling was identified below the lower transition temperature, with significantmore » suppression of the electric polarization on applied magnetic field. Our results show that the lower ferroelectric transition temperature coincides with the Ising-spin paramagnetic transition point, below which the quasi-particle-like monopoles are populated, which indicates implicit correlation between electric dipoles and spin moments. The possible magnetoelectric mechanisms are discussed. Our findings can be used for more investigations to explore multiferroicity in these spin-ice systems and other frustrated magnets.« less

OH-initiated transformation and hydrolysis of aspirin in AOPs system: DFT and experimental studies.

PubMed

He, Lin; Sun, Xiaomin; Zhu, Fanping; Ren, Shaojie; Wang, Shuguang

2017-08-15

Advanced oxidation processes (AOPs) are widely used in wastewater treatment of pharmaceutical and personal care products (PPCPs). In this work, the OH-initiated transformation as well as the hydrolysis of a typical PPCPs, aspirin, was investigated using density functional theory (DFT) calculations and laboratory experiments. For DFT calculations, the frontier electron densities and bond dissociation energies were analyzed. Profiles of the potential energy surface were constructed, and all the possible pathways were discussed. Additionally, rate constants for each pathway were calculated with transition state theory (TST) method. UV/H 2 O 2 experiments of aspirin were performed and degradation intermediates were identified by UPLC-MS-MS analysis. Different findings from previous experimental works were reported that the H-abstraction pathways at methyl position were dominated and OH-addition pathways on benzene ring were also favored. Meantime, hydroxyl ASA was confirmed as the main stable intermediate. Moreover, it was the first time to use DFT method to investigate the hydrolysis mechanisms of organic ester compound. Copyright © 2017 Elsevier B.V. All rights reserved.

Size-of-source Effect in Infrared Thermometers with Direct Reading of Temperature

NASA Astrophysics Data System (ADS)

Manoi, A.; Saunders, P.

2017-07-01

The size-of-source effect (SSE) for six infrared (IR) thermometers with direct reading of temperature was measured in this work. The alternative direct method for SSE determination, where the aperture size is fixed and the measurement distance is varied, was used in this study. The experimental equivalence between the usual and the alternative direct methods is presented. The magnitudes of the SSE for different types of IR thermometers were investigated. The maxima of the SSE were found to be up to 5 %, 8 %, and 28 % for focusable, closed-focus, and open-focus thermometers, respectively. At 275°C, an SSE of 28 % corresponds to 52°C, indicating the severe effect on the accuracy of this type of IR thermometer. A method to realize the calibration conditions used by the manufacturer, in terms of aperture size and measurement distance, is discussed and validated by experimental results. This study would be of benefit to users in choosing the best IR thermometer to match their work and for calibration laboratories in selecting the technique most suitable for determining the SSE.

Effectiveness of working memory training among children with dyscalculia: evidence for transfer effects on mathematical achievement-a pilot study.

PubMed

Layes, Smail; Lalonde, Robert; Bouakkaz, Yamina; Rebai, Mohamed

2017-12-22

We examined whether the working memory (WM) capacity of developmentally dyscalculic children can be improved by a WM training program and whether outcomes relate to mathematical performance. The experimental design comprised two groups with developmental dyslexia with grade 4 schooling: an experimental group (n = 14; mean age = 129.74 months) and a control group (n = 14; mean age = 126.9 months). All participants were assessed on measures of WM, mathematic attainment, and nonverbal mental ability (Raven test) before and after training. The WM training program focused on manipulating and maintaining arithmetic information. The results show that both WM and mathematical performances improved significantly after intervention, indicating a strong relationship between these two constructs. The control group improved slightly in Raven's progressive matrices and a reading number task. These findings are discussed in terms of near and far transfer toward trained and untrained skills and stress the positive impact of WM training on learning mathematics in children with dyscalculia.

Modeling Shock Train Leading Edge Detection in Dual-Mode Scramjets

NASA Astrophysics Data System (ADS)

Ladeinde, Foluso; Lou, Zhipeng; Li, Wenhai

2016-11-01

The objective of this study is to accurately model the detection of shock train leading edge (STLE) in dual-mode scramjet (DMSJ) engines intended for hypersonic flight in air-breathing propulsion systems. The associated vehicles have applications in military warfare and intelligence, and there is commercial interest as well. Shock trains are of interest because they play a significant role in the inability of a DMSJ engine to develop the required propulsive force. The experimental approach to STLE detection has received some attention; as have numerical calculations. However, virtually all of the numerical work focus on mechanically- (i.e., pressure-) generated shock trains, which are much easier to model relative to the phenomenon in the real system where the shock trains are generated by combustion. A focus on combustion, as in the present studies, enables the investigation of the effects of equivalence ratio, which, together with the Mach number, constitutes an important parameter determining mode transition. The various numerical approaches implemented in our work will be reported, with result comparisons to experimental data. The development of an STLE detection procedure in an a priori manner will also be discussed.

Effects of erectable glossal hairs on a honeybee's nectar-drinking strategy

NASA Astrophysics Data System (ADS)

Yang, Heng; Wu, Jianing; Yan, Shaoze

2014-06-01

With the use of a scanning electron microscope, we observe specific microstructures of the mouthpart of the Italian bee (Apis mellifera ligustica), especially the distribution and dimensions of hairs on its glossa. Considering the erection of glossal hairs for trapping nectar modifies the viscous dipping model in analyzing the drinking strategy of a honeybee. Theoretical estimations of volume intake rates with respect to sucrose solutions of different concentrations agree with experimental data, which indicates that erectable hairs can significantly increase the ability of a bee to acquire nectar efficiently. The comparison with experimental results also indicates that a honeybee may continuously augment its pumping power, rather than keep it constant, to drink nectar with sharply increasing viscosity. Under the modified assumption of increasing working power, we introduce the rate at which working power increases with viscosity and discuss the nature-preferred nectar concentration of 35% by theoretically calculating optimal concentration maximizing energetic intake rates under varying increasing rates. Finally, the ability of the mouthparts of the honeybee to transfer viscous nectar may inspire a concept for transporting microfluidics with a wide range of viscosities.

Isoform switching facilitates period control in the Neurospora crassa circadian clock.

PubMed

Akman, Ozgur E; Locke, James C W; Tang, Sanyi; Carré, Isabelle; Millar, Andrew J; Rand, David A

2008-01-01

A striking and defining feature of circadian clocks is the small variation in period over a physiological range of temperatures. This is referred to as temperature compensation, although recent work has suggested that the variation observed is a specific, adaptive control of period. Moreover, given that many biological rate constants have a Q(10) of around 2, it is remarkable that such clocks remain rhythmic under significant temperature changes. We introduce a new mathematical model for the Neurospora crassa circadian network incorporating experimental work showing that temperature alters the balance of translation between a short and long form of the FREQUENCY (FRQ) protein. This is used to discuss period control and functionality for the Neurospora system. The model reproduces a broad range of key experimental data on temperature dependence and rhythmicity, both in wild-type and mutant strains. We present a simple mechanism utilising the presence of the FRQ isoforms (isoform switching) by which period control could have evolved, and argue that this regulatory structure may also increase the temperature range where the clock is robustly rhythmic.

Evolutionary Maps: A new model for the analysis of conceptual development, with application to the diurnal cycle

NASA Astrophysics Data System (ADS)

Navarro, Manuel

2014-05-01

This paper presents a model of how children generate concrete concepts from perception through processes of differentiation and integration. The model informs the design of a novel methodology (evolutionary maps or emaps), whose implementation on certain domains unfolds the web of itineraries that children may follow in the construction of concrete conceptual knowledge and pinpoints, for each conception, the architecture of the conceptual change that leads to the scientific concept. Remarkably, the generative character of its syntax yields conceptions that, if unknown, amount to predictions that can be tested experimentally. Its application to the diurnal cycle (including the sun's trajectory in the sky) indicates that the model is correct and the methodology works (in some domains). Specifically, said emap predicts a number of exotic trajectories of the sun in the sky that, in the experimental work, were drawn spontaneously both on paper and a dome. Additionally, the application of the emaps theoretical framework in clinical interviews has provided new insight into other cognitive processes. The field of validity of the methodology and its possible applications to science education are discussed.

A Novel Soft Pneumatic Artificial Muscle with High-Contraction Ratio.

PubMed

Han, Kwanghyun; Kim, Nam-Ho; Shin, Dongjun

2018-06-20

There is a growing interest in soft actuators for human-friendly robotic applications. However, it is very challenging for conventional soft actuators to achieve both a large working distance and high force. To address this problem, we present a high-contraction ratio pneumatic artificial muscle (HCRPAM), which has a novel actuation concept. The HCRPAM can contract substantially while generating a large force suitable for a wide range of robotic applications. Our proposed prototyping method allows for an easy and quick fabrication, considering various design variables. We derived a mathematical model using a virtual work principle, and validated the model experimentally. We conducted simulations for the design optimization using this model. Our experimental results show that the HCRPAM has a 183.3% larger contraction ratio and 37.1% higher force output than the conventional pneumatic artificial muscle (McKibben muscle). Furthermore, the actuator has a compatible position tracking performance of 1.0 Hz and relatively low hysteresis error of 4.8%. Finally, we discussed the controllable bending characteristics of the HCRPAM, which uses heterogeneous materials and has an asymmetrical structure to make it comfortable for a human to wear.

Experiments on the Dynamics of Molecular Processes: a Chronicle of Fifty Years

NASA Astrophysics Data System (ADS)

Boato, Giovanni; Volpi, Gian Gualberto

1999-10-01

This paper reviews the way in which, in the Italy of the years immediately after World War II, interest in the dynamics of molecular processes was awakened. The narrative begins with the work of a small number of chemists and physicists who, in the initial stage, interacted closely. In the course of the years, their interests diverged and younger people joined the newly formed groups. Even now, after half a century, a common approach can still to be seen regarding how to attack problems and perform experiments. Experimental work is discussed, bringing out the common viewpoint of fields as diverse as mass spectrometry, isotope effects, chemical kinetics, molecular beams, molecule-molecule interactions, molecule-ion interactions, molecule-surface interactions, and plasma chemistry.

Impact of Total Ionizing Dose Radiation Testing and Long-Term Thermal Cycling on the Operation of CMF20120D Silicon Carbide Power MOSFET

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Scheidegger, Robert J.; Lauenstein, Jean-Marie; Casey, Megan; Scheick, Leif; Hammoud, Ahmad

2013-01-01

Power systems designed for use in NASA space missions are required to work reliably under harsh conditions including radiation, thermal cycling, and extreme temperature exposures. Silicon carbide devices show great promise for use in future power electronics systems, but information pertaining to performance of the devices in the space environment is very scarce. A silicon carbide N-channel enhancement-mode power MOSFET called the CMF20120 is of interest for use in space environments. Samples of the device were exposed to radiation followed by long-term thermal cycling to address their reliability for use in space applications. The results of the experimental work are presentd and discussed.

Comparing DNS and Experiments of Subcritical Flow Past an Isolated Surface Roughness Element

NASA Astrophysics Data System (ADS)

Doolittle, Charles; Goldstein, David

2009-11-01

Results are presented from computational and experimental studies of subcritical roughness within a Blasius boundary layer. This work stems from discrepancies presented by Stephani and Goldstein (AIAA Paper 2009-585) where DNS results did not agree with hot-wire measurements. The near wake regions of cylindrical surface roughness elements corresponding to roughness-based Reynolds numbers Rek of about 202 are of specific concern. Laser-Doppler anemometry and flow visualization in water, as well as the same spectral DNS code used by Stephani and Goldstein are used to obtain both quantitative and qualitative comparisons with previous results. Conclusions regarding previous studies will be presented alongside discussion of current work including grid resolution studies and an examination of vorticity dynamics.

Cosmology: from Pomeranchuk to the present day

NASA Astrophysics Data System (ADS)

Dolgov, A. D.

2014-02-01

A review of half a century of cosmology is presented for an intended audience of elementary particle physicists. The review is based on a half-hour seminar talk (at the Institute of Theoretical and Experimental Physics, ITEP) and is therefore brief and superficial. The introductory historical section is mostly devoted to the fundamental work done in, but not always known outside, Russia (USSR). Foundational works and astronomical observations instrumental in shaping the field are discussed, as are inflation, baryosynthesis, dark matter and dark energy, vacuum energy, large-scale gravity modifications, and microwave background angular fluctuations. The presentation is admittedly not entirely objective but rather is given from the Russian (ITEP) perspective and is influenced by the author's personal views and biases.

Determination of work of adhesion of gelatin hydrogels on a glass substrate

NASA Astrophysics Data System (ADS)

Thakre, Avinash A.; Singh, Arun K.

2018-04-01

In this article, work of adhesion (w adh ) of soft gelatin hydrogels on a smooth glass substrate is determined experimentally using the wedge adhesion test. The results showed that w adh decreases with the increase in gelatin concentration in the hydrogels but the same is found to be independent of thickness of hydrogel specimen. These results are used further for establishing a scaling law between w adh and mesh size (ξ) of the three dimensional structure present in the hydrogel as w adh ∼ ξ 8.6. Finite element analysis is also carried out for validating the fracture stability of wedge test in view of analytical prediction. At the end, practical significance of the present study is also discussed.

Separator plugs for liquid helium

NASA Technical Reports Server (NTRS)

Lee, J. M.; Yuan, S. W. K.; Hepler, W. A.; Frederking, T. H. K.

1984-01-01

Work performed during Summer 1984 (from June to Sept. 30) in the area of porous media for use in low temperature applications is discussed. Recent applications are in the area of vapor - liquid phase separation, pumping based on the fountain effect and related subsystems. Areas of potential applications of the latter are outlined in supplementary work. Experimental data have been developed. The linear equations of the two-fluid model are inspected critically in the light of forced convection evidence reported recently. It is emphasized that the Darcy permeability is a unique throughput quantity in the porous media application areas whose use will permit meaningful comparisons of data not only in one lab but also within a group of labs doing porous plug studies.

An experimental and theoretical study of radiative extinction of diffusion flames

NASA Technical Reports Server (NTRS)

Wichman, Indrek S.; Atreya, A.

1994-01-01

Our work was primarily theoretical and numerical. We investigated the simplified modeling of heat losses in diffusion flames, then we 'ramped up' the level of complexity in each successive study until the final chapter discussed the general problem of soot/flame interaction. With regard to the specific objective of studying radiative extinction, we conclude that in the steady case a self-extinguishing zero-g flame is unlikely to occur. The soot volume fractions are too small. On the other hand, our work does provide rational means for assessing the mixture of chemical energy release and radiative heat release. It also provides clues for suitable 'tailoring' this balance. Thus heat fluxes to surrounding surfaces can be substantially increased by exploiting and modifying its sooting capability.

Fisher in Adelaide.

PubMed

Mayo, Oliver

2014-06-01

R. A. Fisher spent much of his final 3 years of life in Adelaide. It was a congenial place to live and work, and he was much in demand as a speaker, in Australia and overseas. It was, however, a difficult time for him because of the sustained criticism of fiducial inference from the early 1950s onwards. The article discusses some of Fisher's work on inference from an Adelaide perspective. It also considers some of the successes arising from this time, in the statistics of field experimentation and in evolutionary genetics. A few personal recollections of Fisher as houseguest are provided. This article is the text of a article presented on August 31, 2012 at the 26th International Biometric Conference, Kobe, Japan. © 2014, The International Biometric Society.

Earth based approaches to enhancing the health and safety of space operations

NASA Technical Reports Server (NTRS)

Koller, A. M., Jr.

1985-01-01

This paper provides an overview of the current state of our earth based knowledge of space safety hazards; identification of several key areas of concern for space operations; and proposed approaches to providing technology enhancement and information needed to improve the health and safety to those conducting space operations. Included are a review of the identified hazards for space oeprations by hazard classification; a summarization of the information currently available on space experiences and an assessment of potential hazards for long duration spaceflight; a discussion of potential failure modes and their significance for Space Station work: and an assessment of current work which indicates additional research and experimentation which can only be accomplished in actual space missions.

Modeling and strain gauging of eddy current repulsion deicing systems

NASA Technical Reports Server (NTRS)

Smith, Samuel O.

1993-01-01

Work described in this paper confirms and extends work done by Zumwalt, et al., on a variety of in-flight deicing systems that use eddy current repulsion for repelling ice. Two such systems are known as electro-impulse deicing (EIDI) and the eddy current repulsion deicing strip (EDS). Mathematical models for these systems are discussed for their capabilities and limitations. The author duplicates a particular model of the EDS. Theoretical voltage, current, and force results are compared directly to experimental results. Dynamic strain measurements results are presented for the EDS system. Dynamic strain measurements near EDS or EIDI coils are complicated by the high magnetic fields in the vicinity of the coils. High magnetic fields induce false voltage signals out of the gages.

Analysis of reaction cross-section production in neutron induced fission reactions on uranium isotope using computer code COMPLET.

PubMed

Asres, Yihunie Hibstie; Mathuthu, Manny; Birhane, Marelgn Derso

2018-04-22

This study provides current evidence about cross-section production processes in the theoretical and experimental results of neutron induced reaction of uranium isotope on projectile energy range of 1-100 MeV in order to improve the reliability of nuclear stimulation. In such fission reactions of 235 U within nuclear reactors, much amount of energy would be released as a product that able to satisfy the needs of energy to the world wide without polluting processes as compared to other sources. The main objective of this work is to transform a related knowledge in the neutron-induced fission reactions on 235 U through describing, analyzing and interpreting the theoretical results of the cross sections obtained from computer code COMPLET by comparing with the experimental data obtained from EXFOR. The cross section value of 235 U(n,2n) 234 U, 235 U(n,3n) 233 U, 235 U(n,γ) 236 U, 235 U(n,f) are obtained using computer code COMPLET and the corresponding experimental values were browsed by EXFOR, IAEA. The theoretical results are compared with the experimental data taken from EXFOR Data Bank. Computer code COMPLET has been used for the analysis with the same set of input parameters and the graphs were plotted by the help of spreadsheet & Origin-8 software. The quantification of uncertainties stemming from both experimental data and computer code calculation plays a significant role in the final evaluated results. The calculated results for total cross sections were compared with the experimental data taken from EXFOR in the literature, and good agreement was found between the experimental and theoretical data. This comparison of the calculated data was analyzed and interpreted with tabulation and graphical descriptions, and the results were briefly discussed within the text of this research work. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Impact of the Intensive Program of Emotional Intelligence (IPEI) on work supervisors.

PubMed

Rodríguez García, Gustavo A; López-Pérez, Belén; Férreo Cruzado, Manuel A; Fernández Carrascoso, María E; Fernández, Juan

2017-11-01

This study aimed to evaluate the effect of the Intensive Program of Emotional Intelligence (IPEI; Fernández, 2016; Férreo, 2016) on middle managers’ emotional intelligence, as this variable may have a significant impact on personal satisfaction, task performance, and the work environment. The intervention was applied to work team supervisors in a large call center, as it is an overlooked sector in this topic. Two-hundred and eighty-two supervisors from a Madrid-based, Spanish multinational (51.4% men and 48.6% women) participated in this study. Participants were assigned to the experimental group (n = 190) or the control group (n = 92) by availability, according to management decision. All supervisors filled in two questionnaires to evaluate the different components of intrapersonal emotional intelligence (i.e., attention, clarity, and repair; TMMS-24; Fernández-Berrocal, Extremera, & Ramos, 2004) and cognitive and affective empathy (i.e., perspective taking, emotion understanding, empathic joy, and personal distress; TECA; López-Pérez, Fernández, & Abad, 2008). The findings showed an increase in the studied variables for the experimental group. The results obtained support middle managers’ training in emotional competences through short, efficient, economic programs. Potential limitations and implications of the results are discussed.

Interaction and Correlation Effects in Quasi Two-dimensional Materials

NASA Astrophysics Data System (ADS)

Louie, Steven G.

2015-03-01

Experimental and theoretical studies of atomically thin quasi two-dimensional materials (typically related to some parent van der Waals layered crystals) and their nanostructures have revealed that these systems can exhibit highly unusual behaviors. In this talk, we discuss some theoretical studies of the electronic, transport and optical properties of such systems. We present results on graphene and graphene nanostructures as well as other quasi-2D systems such as monolayer and few-layer transition metal dichalcogenides (e.g., MoS2, MoSe2, WS2, and WSe2) and metal monochalcogenides (such as GaSe and FeSe). Owing to their reduced dimensionality, these systems present opportunities for unusual manifestation of concepts and phenomena that may not be so prominent or have not been seen in bulk materials. Symmetry and many-body interaction effects often play a critical role in shaping qualitatively and quantitatively their properties. Several quantum phenomena are discussed, including novel and dominant exciton effects, tunable magnetism, electron supercollimation by disorder, unusual plasmon behaviors, and possible enhanced superconductivity in some of these systems. We investigate their physical origins and compare theoretical predictions with experimental data. This work was supported by DOE under Contract No. DE-AC02-05CH11231 and by NSF under Grant No. DMR10-1006184. I would like to acknowledge collaborations with members of the Louie group and the experimental groups of Crommie, Heinz, Wang, and Zhang.

Combustion Characterization and Model Fuel Development for Micro-tubular Flame-assisted Fuel Cells.

PubMed

Milcarek, Ryan J; Garrett, Michael J; Baskaran, Amrish; Ahn, Jeongmin

2016-10-02

Combustion based power generation has been accomplished for many years through a number of heat engine systems. Recently, a move towards small scale power generation and micro combustion as well as development in fuel cell research has created new means of power generation that combine solid oxide fuel cells with open flames and combustion exhaust. Instead of relying upon the heat of combustion, these solid oxide fuel cell systems rely on reforming of the fuel via combustion to generate syngas for electrochemical power generation. Procedures were developed to assess the combustion by-products under a wide range of conditions. While theoretical and computational procedures have been developed for assessing fuel-rich combustion exhaust in these applications, experimental techniques have also emerged. The experimental procedures often rely upon a gas chromatograph or mass spectrometer analysis of the flame and exhaust to assess the combustion process as a fuel reformer and means of heat generation. The experimental techniques developed in these areas have been applied anew for the development of the micro-tubular flame-assisted fuel cell. The protocol discussed in this work builds on past techniques to specify a procedure for characterizing fuel-rich combustion exhaust and developing a model fuel-rich combustion exhaust for use in flame-assisted fuel cell testing. The development of the procedure and its applications and limitations are discussed.

Lorentz violation and gravity

NASA Astrophysics Data System (ADS)

Bailey, Quentin G.

2007-08-01

This work explores the theoretical and experimental aspects of Lorentz violation in gravity. A set of modified Einstein field equations is derived from the general Lorentz-violating Standard-Model Extension (SME). Some general theoretical implications of these results are discussed. The experimental consequences for weak-field gravitating systems are explored in the Earth- laboratory setting, the solar system, and beyond. The role of spontaneous Lorentz-symmetry breaking is discussed in the context of the pure-gravity sector of the SME. To establish the low-energy effective Einstein field equations, it is necessary to take into account the dynamics of 20 coefficients for Lorentz violation. As an example, the results are compared with bumblebee models, which are general theories of vector fields with spontaneous Lorentz violation. The field equations are evaluated in the post- newtonian limit using a perfect fluid description of matter. The post-newtonian metric of the SME is derived and compared with some standard test models of gravity. The possible signals for Lorentz violation due to gravity-sector coefficients are studied. Several new effects are identified that have experimental implications for current and future tests. Among the unconventional effects are a new type of spin precession for a gyroscope in orbit and a modification to the local gravitational acceleration on the Earth's surface. These and other tests are expected to yield interesting sensitivities to dimensionless gravity- sector coefficients.

Modelling the structure of Zr-rich Pb(Zr1-xTix)O3, x = 0.4 by a multiphase approach.

PubMed

Bogdanov, Alexander; Mysovsky, Andrey; Pickard, Chris J; Kimmel, Anna V

2016-10-12

Solid solution perovskite Pb(Zr 1-x Ti x )O 3 (PZT) is an industrially important material. Despite the long history of experimental and theoretical studies, the structure of this material is still under intensive discussion. In this work, we have applied structure searching coupled with density functional theory methods to provide a multiphase description of this material at x = 0.4. We demonstrate that the permutational freedom of B-site cations leads to the stabilisation of a variety of local phases reflecting a relatively flat energy landscape of PZT. Using a set of predicted local phases we reproduce the experimental pair distribution function (PDF) profile with high accuracy. We introduce a complex multiphase picture of the structure of PZT and show that additional monoclinic and rhombohedral phases account for a better description of the experimental PDF profile. We propose that such a multiphase picture reflects the entropy reached in the sample during the preparation process.

Comparing the influence of physical and virtual manipulatives in the context of the Physics by Inquiry curriculum: The case of undergraduate students' conceptual understanding of heat and temperature

NASA Astrophysics Data System (ADS)

Zacharia, Zacharias C.; Constantinou, Constantinos P.

2008-04-01

We compare the effect of experimenting with physical or virtual manipulatives on undergraduate students' conceptual understanding of heat and temperature. A pre-post comparison study design was used to replicate all aspects of a guided inquiry classroom except the mode in which students performed their experiments. This study is the first on physical and virtual manipulative experimentation in physics in which the curriculum, method of instruction, and resource capabilities were explicitly controlled. The participants were 68 undergraduates in an introductory course and were randomly assigned to an experimental or a control group. Conceptual tests were administered to both groups to assess students' understanding before, during, and after instruction. The result indicates that both modes of experimentation are equally effective in enhancing students' conceptual understanding. This result is discussed in the context of an ongoing debate on the relative importance of virtual and real laboratory work in physics education.

Studies on absorption coefficient near edge of multi elements

NASA Astrophysics Data System (ADS)

Eisa, M. H.; Shen, H.; Yao, H. Y.; Mi, Y.; Zhou, Z. Y.; Hu, T. D.; Xie, Y. N.

2005-12-01

X-ray absorption near edge structure (XANES) was used to study the near edge mass-absorption coefficients of seven elements, such as, Ti, V, Fe, Co, Ni, Cu and Zn. It is well known that, on the near edge absorption of element, when incident X-ray a few eV change can make the absorption coefficient an order magnitude alteration. So that, there are only a few points mass-absorption coefficient at the near edge absorption and that always average value in published table. Our results showed a wide range of data, the total measured data of mass-absorption coefficient of the seven elements was about 505. The investigation confirmed that XANES is useful technique for multi-element absorption coefficient measurement. Details of experimental methods and results are given and discussed. The experimental work has been performed at Beijing Synchrotron Radiation Facility. The measured values were compared with the published data. Good agreement between experimental results and published data is obtained.

Crystal plasticity modeling of irradiation growth in Zircaloy-2

NASA Astrophysics Data System (ADS)

Patra, Anirban; Tomé, Carlos N.; Golubov, Stanislav I.

2017-08-01

A physically based reaction-diffusion model is implemented in the visco-plastic self-consistent (VPSC) crystal plasticity framework to simulate irradiation growth in hcp Zr and its alloys. The reaction-diffusion model accounts for the defects produced by the cascade of displaced atoms, their diffusion to lattice sinks and the contribution to crystallographic strain at the level of single crystals. The VPSC framework accounts for intergranular interactions and irradiation creep, and calculates the strain in the polycrystalline ensemble. A novel scheme is proposed to model the simultaneous evolution of both, number density and radius, of irradiation-induced dislocation loops directly from experimental data of dislocation density evolution during irradiation. This framework is used to predict the irradiation growth behaviour of cold-worked Zircaloy-2 and trends compared to available experimental data. The role of internal stresses in inducing irradiation creep is discussed. Effects of grain size, texture and external stress on the coupled irradiation growth and creep behaviour are also studied and compared with available experimental data.

A century of cell adhesion: from the blastomere to the clinic part 1: conceptual and experimental foundations and the pre-molecular era.

PubMed

Grunwald, Gerald B

2013-12-01

The historical roots of cell adhesion research stretch back over a hundred years, commencing with fundamental questions from the advent of experimental embryology in the late nineteenth century. The transition of embryology from a descriptive to an experimentally driven and mechanistic branch of the biological sciences included investigations focused on the interactions of the first cells of the newly developing embryo, the blastomeres, and followed the movement, interactions and fate of these cells as the tissues and organs of the growing embryo took form. Of special interest to early investigators were cell-cell contacts, which were obviously dynamic but of an obscure nature. This historical review, the first of a series, explores the early years of the cell adhesion field, including the work of Roux, Wilson, Galtsoff, Just and Holtfreter, and discusses the classical experiments, observations and conceptual developments that formed the cornerstone of cell adhesion research during its premolecular era.

Effectiveness of Student Learning during Experimental Work in Primary School.

PubMed

Logar, Ana; Peklaj, Cirila; Ferk Savec, Vesna

2017-09-01

The aim of the research was to optimize the effectiveness of student learning based on experimental work in chemistry classes in Slovenian primary schools. To obtain evidence about how experimental work is implemented during regular chemistry classes, experimental work was videotaped during 19 units of chemistry lessons at 12 Slovenian primary schools from the pool of randomly selected schools. Altogether 332 eight-grade students were involved in the investigation, with an average age of 14.2 years. Students were videotaped during chemistry lessons, and their worksheets were collected afterward. The 12 chemistry teachers, who conducted lessons in these schools, were interviewed before the lessons; their teaching plans were also collected. The collected data was analyzed using qualitative methods. The results indicate that many teachers in Slovenian primary schools are not fully aware of the potential of experimental work integrated into chemistry lessons for the development of students' experimental competence. Further research of the value of different kinds of training to support teachers for the use of experimental work in chemistry teaching is needed.

Modeling Core Collapse Supernovae

NASA Astrophysics Data System (ADS)

Mezzacappa, Anthony

2017-01-01

Core collapse supernovae, or the death throes of massive stars, are general relativistic, neutrino-magneto-hydrodynamic events. The core collapse supernova mechanism is still not in hand, though key components have been illuminated, and the potential for multiple mechanisms for different progenitors exists. Core collapse supernovae are the single most important source of elements in the Universe, and serve other critical roles in galactic chemical and thermal evolution, the birth of neutron stars, pulsars, and stellar mass black holes, the production of a subclass of gamma-ray bursts, and as potential cosmic laboratories for fundamental nuclear and particle physics. Given this, the so called ``supernova problem'' is one of the most important unsolved problems in astrophysics. It has been fifty years since the first numerical simulations of core collapse supernovae were performed. Progress in the past decade, and especially within the past five years, has been exponential, yet much work remains. Spherically symmetric simulations over nearly four decades laid the foundation for this progress. Two-dimensional modeling that assumes axial symmetry is maturing. And three-dimensional modeling, while in its infancy, has begun in earnest. I will present some of the recent work from the ``Oak Ridge'' group, and will discuss this work in the context of the broader work by other researchers in the field. I will then point to future requirements and challenges. Connections with other experimental, observational, and theoretical efforts will be discussed, as well.

Development of Methods to Predict the Effects of Test Media in Ground-Based Propulsion Testing

NASA Technical Reports Server (NTRS)

Drummond, J. Philip; Danehy, Paul M.; Gaffney, Richard L., Jr.; Parker, Peter A.; Tedder, Sarah A.; Chelliah, Harsha K.; Cutler, Andrew D.; Bivolaru, Daniel; Givi, Peyman; Hassan, Hassan A.

2009-01-01

This report discusses work that began in mid-2004 sponsored by the Office of the Secretary of Defense (OSD) Test & Evaluation/Science & Technology (T&E/S&T) Program. The work was undertaken to improve the state of the art of CFD capabilities for predicting the effects of the test media on the flameholding characteristics in scramjet engines. The program had several components including the development of advanced algorithms and models for simulating engine flowpaths as well as a fundamental experimental and diagnostic development effort to support the formulation and validation of the mathematical models. This report provides details of the completed work, involving the development of phenomenological models for Reynolds averaged Navier-Stokes codes, large-eddy simulation techniques and reduced-kinetics models. Experiments that provided data for the modeling efforts are also described, along with with the associated nonintrusive diagnostics used to collect the data.

Predicting the Effects of Test Media in Ground-Based Propulsion Testing

NASA Technical Reports Server (NTRS)

Drummond, J. Philip; Danehy, Paul M.; Bivolaru, Daniel; Gaffney, Richard L.; Parker, Peter A.; Chelliah, Harsha K.; Cutler, Andrew D.; Givi, Peyman; Hassan, Hassan, A.

2006-01-01

This paper discusses the progress of work which began in mid-2004 sponsored by the Office of the Secretary of Defense (OSD) Test & Evaluation/Science & Technology (T&E/S&T) Program. The purpose of the work is to improve the state of the art of CFD capabilities for predicting the effects of the test media on the flameholding characteristics in scramjet engines. The program has several components including the development of advance algorithms and models for simulating engine flowpaths as well as a fundamental experimental and diagnostic development effort to support the formulation and validation of the mathematical models. The paper will provide details of current work involving the development of phenomenological models for Reynolds averaged Navier-Stokes codes, large-eddy simulation techniques and reduced-kinetics models. Experiments that will provide data for the modeling efforts will also be described, along with with the associated nonintrusive diagnostics used to collect the data.

Neural Effects of Short-Term Training on Working Memory

PubMed Central

Buschkuehl, Martin; Garcia, Luis Hernandez; Jaeggi, Susanne M.; Bernard, Jessica A.; Jonides, John

2014-01-01

Working memory training has been the focus of intense research interest. Despite accumulating behavioral work, knowledge about the neural mechanisms underlying training effects is scarce. Here we show that seven days of training on an n back task lead to substantial performance improvements in the trained task; furthermore, the experimental group shows cross modal transfer as compared to an active control group. In addition, there are two neural effects that emerged as a function of training: first, increased perfusion during task performance in selected regions, reflecting a neural response to cope with high task demand; second, increased blood flow at rest in regions where training effects were apparent. We also found that perfusion at rest was correlated with task proficiency, probably reflecting an improved neural readiness to perform. Our findings are discussed within the context of the available neuroimaging literature on n back training. PMID:24496717

EMC effect: Past, Present, and Future

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

Fomin, Nadia

2015-09-01

Since the discovery of the EMC effect over 30 years ago, it has been of great theoretical interest and studied in several experimental measurements. No unified picture arose to explain the underlying cause of per nucleon structure function modification in nuclei. Precise measurements on light nuclei from JLab’s 6 GeV era revitalized this research by showing that traditional A or density dependent models of this nuclear modification do not work. The measurements will be reviewed, discussed and preliminary data on heavy targets from JLab’s E03-103 will be presented.

An overview of the nonequilibrium behavior of polymer glasses

NASA Technical Reports Server (NTRS)

Tant, M. R.; Wilkes, G. L.

1981-01-01

It is pointed out that research efforts are at present being directed in two areas, one comprising experimental studies of this phenomenon in various glassy polymer systems and the other involving the development of a quantitative theory capable of satisfactorily predicting aging behavior for a variety of polymer materials under different conditions. Recent work in both these areas is surveyed. The basic principles of nonequilibrium behavior are outlined, with emphasis placed on changes in material properties with annealing below the glass transition temperature. Free volume theory and thermodynamic theory are discussed.

Experimental Investigation of Nozzle/Plume Aerodynamics at Hypersonic Speeds

NASA Technical Reports Server (NTRS)

Heinemann, K.; Bogdanoff, David W.; Cambier, Jean-Luc

1992-01-01

The work performed by D. W. Bogdanoff and J.-L. Cambier during the period of 1 Feb. - 31 Oct. 1992 is presented. The following topics are discussed: (1) improvement in the operation of the facility; (2) the wedge model; (3) calibration of the new test section; (4) combustor model; (5) hydrogen fuel system for combustor model; (6) three inch calibration/development tunnel; (7) shock tunnel unsteady flow; (8) pulse detonation wave engine; (9) DCAF flow simulation; (10) high temperature shock layer simulation; and (11) the one dimensional Godunov CFD code.

Actin-based motility of Listeria: Right-handed helical trajectories

NASA Astrophysics Data System (ADS)

Rangarajan, Murali

2012-06-01

Bacteria such as Listeria monocytogenes recruit cellular machinery to move in and between cells. Understanding the mechanism of motility, including force and torque generation and the resultant displacements, holds keys to numerous applications in medicine and biosensing. In this work, a simple back-of-the-envelope calculation is presented to illustrate that a biomechanical model of actin-based motility of a rigid surface through persistently attached filaments propelled by affinity-modulated molecular motors can produce a right-handed helical trajectory consistent with experimental observations. The implications of the mechanism to bacterial motility are discussed.

Experimental Optimization Methods for Multi-Element Airfoils

NASA Technical Reports Server (NTRS)

Landman, Drew; Britcher, Colin P.

1996-01-01

A modern three element airfoil model with a remotely activated flap was used to investigate optimum flap testing position using an automated optimization algorithm in wind tunnel tests. Detailed results for lift coefficient versus flap vertical and horizontal position are presented for two angles of attack: 8 and 14 degrees. An on-line first order optimizer is demonstrated which automatically seeks the optimum lift as a function of flap position. Future work with off-line optimization techniques is introduced and aerodynamic hysteresis effects due to flap movement with flow on are discussed.

RSVP: An experimental organization.

PubMed

Oram, P G

1967-09-01

RSVP is a volunteer organization of psychologists formed to facilitate participation in community activities. Its first venture was in working with 10 tutoring programs in the Boston area. Emphasis in the first year was on discovering areas in which psychologists could be helpful. Projects included group discussion leadership, workshops, and recruitment of tutors and professionals. At present the organization is attempting to broaden the number and kind of activities in which it is engaged and is facing a number of questions relative to future programs. The members consider that RSVP has been a successful experiment.

Collective gradient sensing and chemotaxis: modeling and recent developments

NASA Astrophysics Data System (ADS)

Camley, Brian A.

2018-06-01

Cells measure a vast variety of signals, from their environment’s stiffness to chemical concentrations and gradients; physical principles strongly limit how accurately they can do this. However, when many cells work together, they can cooperate to exceed the accuracy of any single cell. In this topical review, I will discuss the experimental evidence showing that cells collectively sense gradients of many signal types, and the models and physical principles involved. I also propose new routes by which experiments and theory can expand our understanding of these problems.

Skylab parasol material evaluation

NASA Technical Reports Server (NTRS)

Jacobs, S.

1975-01-01

Results of experimental work to evaluate the degradation rate of a parasol that was used as a means of alleviating thermal problems encountered soon after the launch of the Skylab 1 space vehicle are presented. Material selection criteria are discussed; the material chosen is described, and results of tests performed after environmental exposure at five facilities are given. The facilities used for exposure to ultraviolet radiation/thermal-vacuum environments and the equipment used for testing physical properties before and after exposure are described. Comparisons of ground test and flight test data are included.

The built-in environment: the role of personality and physical activity.

PubMed

Rhodes, Ryan E

2006-04-01

Personality trait psychology has seen a reemergence in recent years, and researchers are beginning to apply personality models to understand health behavior habits. This review features recent research on personality correlates of physical activity (PA) and the integration of personality with PA-related social cognition. The current definition and status of general personality work is introduced followed by a review and discussion of the evidence for personality and PA relations. The review concludes with recommendations for personality-matched PA marketing and experimental and longitudinal designs.

Development of a sensitive superconducting gravity gradiometer for geological and navigational applications

NASA Technical Reports Server (NTRS)

Paik, H. J.; Richard, J. P.

1986-01-01

A sensitive and stable gravity gradiometer would provide high resolution gravity measurements from space. The instrument could also provide precision tests of fundamental laws of physics and be applied to inertial guidance systems of the future. This report describes research on the superconducting gravity gradiometer program at the University of Maryland from July 1980 to July 1985. The report describes the theoretical and experimental work on a prototype superconducting gravity gradiometer. The design of an advanced three-axis superconducting gravity gradiometer is also discussed.

BMC Blood Disorders becomes BMC Hematology: evolving along with the hematology field

PubMed Central

2013-01-01

This Editorial marks the launch of BMC Hematology, formerly known as BMC Blood Disorders, within the BMC series of journals published by BioMed Central. The scope of BMC Hematology encompasses basic, experimental and clinical research related to hematology. In this Editorial we will discuss the rationale behind this relaunch and how, as an open access journal providing unrestricted and free access to scientific and scholarly work, BMC Hematology will help disseminate research in the hematology field in a freely-accessible manner. PMID:24499661

The Development of a Physician Vitality Program: A Brief Report.

PubMed

Hernandez, Barbara Couden; Thomas, Tamara L

2015-10-01

We describe the development of an innovative program to support physician vitality. We provide the context and process of program delivery which includes a number of experimental support programs. We discuss a model for intervention and methods used to enhance physician resilience, support work-life balance, and change the culture to one that explicitly addresses the physician's biopsychosocial-spiritual needs. Recommendations are given for marriage and family therapists (MFTs) who wish to develop similar support programs for healthcare providers. Video Abstract. © 2014 American Association for Marriage and Family Therapy.

Current Results and Proposed Activities in Microgravity Fluid Dynamics

NASA Technical Reports Server (NTRS)

Polezhaev, V. I.

1996-01-01

The Institute for Problems in Mechanics' Laboratory work in mathematical and physical modelling of fluid mechanics develops models, methods, and software for analysis of fluid flow, instability analysis, direct numerical modelling and semi-empirical models of turbulence, as well as experimental research and verification of these models and their applications in technological fluid dynamics, microgravity fluid mechanics, geophysics, and a number of engineering problems. This paper presents an overview of the results in microgravity fluid dynamics research during the last two years. Nonlinear problems of weakly compressible and compressible fluid flows are discussed.

GPR application on construction foundation study

NASA Astrophysics Data System (ADS)

Amran, T. S. T.; Ismail, M. P.; Ismail, M. A.; Amin, M. S. M.; Ahmad, M. R.; Basri, N. S. M.

2017-11-01

Extensive researches and studies have been carried on radar system for commercialisation of ground penetrating radar (GPR) technology pioneered in construction, and thus claimed its rightful place in the vision of future. The application of ground penetrating radar in construction study is briefly reviewed. Based on previous experimentation and studies, this paper is focus on reinforcement bar (rebar) investigation on construction. The various data through previous references used to discuss and analyse the capability of ground penetrating radar for further improvement in construction projects especially in rebar placement in works.

Design of a CO2 laser power control system for a Spacelab microgravity experiment

NASA Technical Reports Server (NTRS)

Wenzler, Carl J.; Eichenberg, Dennis J.

1990-01-01

The surface tension driven convection experiment (STDCE) is a Space Transportation System flight experiment manifested to fly aboard the USML-1 Spacelab mission. A CO2 laser is used to heat a spot on the surface of silicone oil contained inside a test chamber. Several CO2 laser control systems were evaluated and the selected system will be interfaced with the balance of the experimental hardware to constitute a working engineering model. Descriptions and a discussion of these various design approaches are presented.

System software for the finite element machine

NASA Technical Reports Server (NTRS)

Crockett, T. W.; Knott, J. D.

1985-01-01

The Finite Element Machine is an experimental parallel computer developed at Langley Research Center to investigate the application of concurrent processing to structural engineering analysis. This report describes system-level software which has been developed to facilitate use of the machine by applications researchers. The overall software design is outlined, and several important parallel processing issues are discussed in detail, including processor management, communication, synchronization, and input/output. Based on experience using the system, the hardware architecture and software design are critiqued, and areas for further work are suggested.

Experiment Definition Using the Space Laboratory, Long Duration Exposure Facility, and Space Transportation System Shuttle

NASA Technical Reports Server (NTRS)

Sheppard, Albert P.; Wood, Joan M.

1976-01-01

Candidate experiments designed for the space shuttle transportation system and the long duration exposure facility are summarized. The data format covers: experiment title, Experimenter, technical abstract, benefits/justification, technical discussion of experiment approach and objectives, related work and experience, experiment facts space properties used, environmental constraints, shielding requirements, if any, physical description, and sketch of major elements. Information was also included on experiment hardware, research required to develop experiment, special requirements, cost estimate, safety considerations, and interactions with spacecraft and other experiments.